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Sample records for adenosine triphosphate

  1. Imaging Adenosine Triphosphate (ATP).

    Science.gov (United States)

    Rajendran, Megha; Dane, Eric; Conley, Jason; Tantama, Mathew

    2016-08-01

    Adenosine triphosphate (ATP) is a universal mediator of metabolism and signaling across unicellular and multicellular species. There is a fundamental interdependence between the dynamics of ATP and the physiology that occurs inside and outside the cell. Characterizing and understanding ATP dynamics provide valuable mechanistic insight into processes that range from neurotransmission to the chemotaxis of immune cells. Therefore, we require the methodology to interrogate both temporal and spatial components of ATP dynamics from the subcellular to the organismal levels in live specimens. Over the last several decades, a number of molecular probes that are specific to ATP have been developed. These probes have been combined with imaging approaches, particularly optical microscopy, to enable qualitative and quantitative detection of this critical molecule. In this review, we survey current examples of technologies available for visualizing ATP in living cells, and identify areas where new tools and approaches are needed to expand our capabilities.

  2. Optical Aptasensors for Adenosine Triphosphate

    Science.gov (United States)

    Ng, Stella; Lim, Hui Si; Ma, Qian; Gao, Zhiqiang

    2016-01-01

    Nucleic acids are among the most researched and applied biomolecules. Their diverse two- and three-dimensional structures in conjunction with their robust chemistry and ease of manipulation provide a rare opportunity for sensor applications. Moreover, their high biocompatibility has seen them being used in the construction of in vivo assays. Various nucleic acid-based devices have been extensively studied as either the principal element in discrete molecule-like sensors or as the main component in the fabrication of sensing devices. The use of aptamers in sensors - aptasensors, in particular, has led to improvements in sensitivity, selectivity, and multiplexing capacity for a wide verity of analytes like proteins, nucleic acids, as well as small biomolecules such as glucose and adenosine triphosphate (ATP). This article reviews the progress in the use of aptamers as the principal component in sensors for optical detection of ATP with an emphasis on sensing mechanism, performance, and applications with some discussion on challenges and perspectives. PMID:27446501

  3. Adenosine triphosphate inhibition of yeast trehalase.

    Science.gov (United States)

    Panek, A D

    1969-09-01

    Yeast trehalase has been found to be inhibited non-competitively by adenosine triphosphate. Such a biological control could explain the accumulation of trehalose during the stationary phase of the growth curve. PMID:5370287

  4. Chemoelectrical energy conversion of adenosine triphosphate

    Science.gov (United States)

    Sundaresan, Vishnu Baba; Sarles, Stephen Andrew; Leo, Donald J.

    2007-04-01

    Plant and animal cell membranes transport charged species, neutral molecules and water through ion pumps and channels. The energy required for moving species against established concentration and charge gradients is provided by the biological fuel - adenosine triphosphate (ATP) -synthesized within the cell. The adenosine triphosphatase (ATPases) in a plant cell membrane hydrolyze ATP in the cell cytoplasm to pump protons across the cell membrane. This establishes a proton gradient across the membrane from the cell exterior into the cell cytoplasm. This proton motive force stimulates ion channels that transport nutrients and other species into the cell. This article discusses a device that converts the chemical energy stored in adenosine triphosphate into electrical power using a transporter protein, ATPase. The V-type ATPase proteins used in our prototype are extracted from red beet(Beta vulgaris) tonoplast membranes and reconstituted in a bilayer lipid membrane or BLM formed from POPC and POPS lipids. A pH7 medium that can support ATP hydrolysis is provided on both sides of the membrane and ATP is dissolved in the pH7 buffer on one side of the membrane. Hydrolysis of ATP results in the formation of a phosphate ion and adenosine diphosphate. The energy from the reaction activates ATPase in the BLM and moves a proton across the membrane. The charge gradient established across the BLM due to the reaction and ion transport is converted into electrical current by half-cell reference electrodes. The prototype ATPase cell with an effective BLM area of 4.15 mm2 carrying 15 μl of ATPase proteins was observed to develop a steady state peak power output of 70 nW, which corresponds to a specific power of 1.69 μW/cm2 and a current density of 43.4 μA/cm2 of membrane area.

  5. 21 CFR 864.7040 - Adenosine triphosphate release assay.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Adenosine triphosphate release assay. 864.7040 Section 864.7040 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... disorders. (b) Classification. Class I (general controls)....

  6. Treatment of paroxysmal supraventricular tachycardia with intravenous injection of adenosine triphosphate.

    OpenAIRE

    Saito, D.; Ueeda, M; Abe, Y.; Tani, H; Nakatsu, T.; Yoshida, H.; Haraoka, S; Nagashima, H

    1986-01-01

    Intravenous adenosine triphosphate rapidly terminated all 11 episodes of paroxysmal supraventricular tachycardia in 10 patients. Eight patients reported side effects but these resolved within 20 seconds and did not require treatment. Adenosine triphosphate is a suitable agent for the rapid termination of paroxysmal supraventricular tachycardia.

  7. Autophagy occurs within an hour of adenosine triphosphate treatment after nerve cell damage:the neuroprotective effects of adenosine triphosphate against apoptosis

    Institute of Scientific and Technical Information of China (English)

    Na Lu; Baoying Wang; Xiaohui Deng; Honggang Zhao; Yong Wang; Dongliang Li

    2014-01-01

    After hypoxia, ischemia, or inlfammatory injuries to the central nervous system, the damaged cells release a large amount of adenosine triphosphate, which may cause secondary neuronal death. Autophagy is a form of cell death that also has neuroprotective effects. Cell Counting Kit assay, monodansylcadaverine staining, lfow cytometry, western blotting, and real-time PCR were used to determine the effects of exogenous adenosine triphosphate treatment at different concentrations (2, 4, 6, 8, 10 mmol/L) over time (1, 2, 3, and 6 hours) on the apoptosis and autophagy of SH-SY5Y cells. High concentrations of extracellular adenosine triphosphate induced autophagy and apoptosis of SH-SY5Y cells. The enhanced autophagy ifrst appeared, and peaked at 1 hour after treatment with adenosine triphosphate. Cell apoptosis peaked at 3 hours, and persisted through 6 hours. With prolonged exposure to the adenosine triphosphate treatment, the fraction of apoptotic cells increased. These data suggest that the SH-SY5Y neural cells initiated autophagy against apoptosis within an hour of adenosine triphosphate treatment to protect themselves against injury.

  8. Electroacupuncture improves neuropathic pain Adenosine,adenosine 5'-triphosphate disodium and their receptors perhaps change simultaneously

    Institute of Scientific and Technical Information of China (English)

    Wen Ren; Wenzhan Tu; Songhe Jiang; Ruidong Cheng; Yaping Du

    2012-01-01

    Applying a stimulating current to acupoints through acupuncture needles-known as electroacupuncture-has the potential to produce analgesic effects in human subjects and experimental animals.When acupuncture was applied in a rat model,adenosine 5'-triphosphate disodium in the extracellular space was broken down into adenosine,which in turn inhibited pain transmission by means of an adenosine A1 receptor-dependent process.Direct injection of an adenosine A1 receptor agonist enhanced the analgesic effect of acupuncture.The analgesic effect of acupuncture appears to be mediated by activation of A1 receptors located on ascending nerves.In neuropathic pain,there is upregulation of P2X purinoceptor 3(P2X3)receptor expression in dorsal root ganglion neurons.Conversely,the onset of mechanical hyperalgesia was diminished and established hyperalgesia was significantly reversed when P2X3 receptor expression was downregulated.The pathways upon which electroacupuncture appear to act are interwoven with pain pathways,and electroacupuncture stimuli converge with impulses originating from painful areas.Electroacupuncture may act via purinergic A1 and P2X3 receptors simultaneously to induce an analgesic effect on neuropathic pain.

  9. Laboratory procedures manual for the firefly luciferase assay for adenosine triphosphate (ATP)

    Science.gov (United States)

    Chappelle, E. W.; Picciolo, G. L.; Curtis, C. A.; Knust, E. A.; Nibley, D. A.; Vance, R. B.

    1975-01-01

    A manual on the procedures and instruments developed for the adenosine triphosphate (ATP) luciferase assay is presented. Data cover, laboratory maintenance, maintenance of bacterial cultures, bacteria measurement, reagents, luciferase procedures, and determination of microbal susceptibility to antibiotics.

  10. Cyclization of the phosphate side chain of adenosine triphosphate: formation of monoadenosine 5'-trimetaphosphate.

    Science.gov (United States)

    Glonek, T; Kleps, R A; Myers, T C

    1974-07-26

    Monoadenosine 5'-trimetaphosphate has been prepared from adeno-sine 5'-triphosphate by a carbodiimide-mediated condensation. The molecule was characterized by (3l)P nuclear magnetic resonance, and its (31)P spectrum was simulated through the assumption of a three-phosphorus spin system. The molecule is highly reactive and is rapidly converted to adenosine triphosphate upon contact with water. PMID:4834364

  11. Adenosine triphosphate inhibits melatonin synthesis in the rat pineal gland.

    Science.gov (United States)

    Souza-Teodoro, Luis Henrique; Dargenio-Garcia, Letícia; Petrilli-Lapa, Camila Lopes; Souza, Ewerton da Silva; Fernandes, Pedro A C M; Markus, Regina P; Ferreira, Zulma S

    2016-03-01

    Adenosine triphosphate (ATP) is released onto the pinealocyte, along with noradrenaline, from sympathetic neurons and triggers P2Y1 receptors that enhance β-adrenergic-induced N-acetylserotonin (NAS) synthesis. Nevertheless, the biotransformation of NAS into melatonin, which occurs due to the subsequent methylation by acetylserotonin O-methyltransferase (ASMT; EC 2.1.1.4), has not yet been evaluated in the presence of purinergic stimulation. We therefore evaluated the effects of purinergic signaling on melatonin synthesis induced by β-adrenergic stimulation. ATP increased NAS levels, but, surprisingly, inhibited melatonin synthesis in an inverse, concentration-dependent manner. Our results demonstrate that enhanced NAS levels, which depend on phospholipase C (PLC) activity (but not the induction of gene transcription), are a post-translational effect. By contrast, melatonin reduction is related to an ASMT inhibition of expression at both the gene transcription and protein levels. These results were independent of nuclear factor-kappa B (NF-kB) translocation. Neither the P2Y1 receptor activation nor the PLC-mediated pathway was involved in the decrease in melatonin, indicating that ATP regulates pineal metabolism through different mechanisms. Taken together, our data demonstrate that purinergic signaling differentially modulates NAS and melatonin synthesis and point to a regulatory role for ATP as a cotransmitter in the control of ASMT, the rate-limiting enzyme in melatonin synthesis. The endogenous production of melatonin regulates defense responses; therefore, understanding the mechanisms involving ASMT regulation might provide novel insights into the development and progression of neurological disorders since melatonin presents anti-inflammatory, neuroprotective, and neurogenic effects. PMID:26732366

  12. Behavior and stability of adenosine triphosphate (ATP) during chlorine disinfection.

    Science.gov (United States)

    Nescerecka, Alina; Juhna, Talis; Hammes, Frederik

    2016-09-15

    Adenosine triphosphate (ATP) analysis is a cultivation-independent alternative method for the determination of bacterial viability in both chlorinated and non-chlorinated water. Here we investigated the behavior and stability of ATP during chlorination in detail. Different sodium hypochlorite doses (0-22.4 mg-Cl2 L(-1); 5 min exposure) were applied to an Escherichia coli pure culture suspended in filtered river water. We observed decreasing intracellular ATP with increasing chlorine concentrations, but extracellular ATP concentrations only increased when the chlorine dose exceeded 0.35 mg L(-1). The release of ATP from chlorine-damaged bacteria coincided with severe membrane damage detected with flow cytometry (FCM). The stability of extracellular ATP was subsequently studied in different water matrixes, and we found that extracellular ATP was stable in sterile deionized water and also in chlorinated water until extremely high chlorine doses (≤11.2 mg-Cl2 L(-1); 5 min exposure). In contrast, ATP decreased relatively slowly (k = 0.145 h(-1)) in 0.1 μm filtered river water, presumably due to degradation by either extracellular enzymes or the fraction of bacteria that were able to pass through the filter. Extracellular ATP decreased considerably faster (k = 0.368 h(-1)) during batch growth of a river water bacterial community. A series of growth potential tests showed that extracellular ATP molecules were utilized as a phosphorus source during bacteria proliferation. From the combined data we conclude that ATP released from bacteria at high chlorine doses could promote bacteria regrowth, contributing to biological instability in drinking water distribution systems. PMID:27295623

  13. Behavior and stability of adenosine triphosphate (ATP) during chlorine disinfection.

    Science.gov (United States)

    Nescerecka, Alina; Juhna, Talis; Hammes, Frederik

    2016-09-15

    Adenosine triphosphate (ATP) analysis is a cultivation-independent alternative method for the determination of bacterial viability in both chlorinated and non-chlorinated water. Here we investigated the behavior and stability of ATP during chlorination in detail. Different sodium hypochlorite doses (0-22.4 mg-Cl2 L(-1); 5 min exposure) were applied to an Escherichia coli pure culture suspended in filtered river water. We observed decreasing intracellular ATP with increasing chlorine concentrations, but extracellular ATP concentrations only increased when the chlorine dose exceeded 0.35 mg L(-1). The release of ATP from chlorine-damaged bacteria coincided with severe membrane damage detected with flow cytometry (FCM). The stability of extracellular ATP was subsequently studied in different water matrixes, and we found that extracellular ATP was stable in sterile deionized water and also in chlorinated water until extremely high chlorine doses (≤11.2 mg-Cl2 L(-1); 5 min exposure). In contrast, ATP decreased relatively slowly (k = 0.145 h(-1)) in 0.1 μm filtered river water, presumably due to degradation by either extracellular enzymes or the fraction of bacteria that were able to pass through the filter. Extracellular ATP decreased considerably faster (k = 0.368 h(-1)) during batch growth of a river water bacterial community. A series of growth potential tests showed that extracellular ATP molecules were utilized as a phosphorus source during bacteria proliferation. From the combined data we conclude that ATP released from bacteria at high chlorine doses could promote bacteria regrowth, contributing to biological instability in drinking water distribution systems.

  14. Unexpected Discovery of Dichloroacetate Derived Adenosine Triphosphate Competitors Targeting Pyruvate Dehydrogenase Kinase To Inhibit Cancer Proliferation.

    Science.gov (United States)

    Zhang, Shao-Lin; Hu, Xiaohui; Zhang, Wen; Tam, Kin Yip

    2016-04-14

    Pyruvate dehydrogenase kinases (PDKs) have recently emerged as an attractive target for cancer therapy. Herein, we prepared a series of compounds derived from dichloroacetate (DCA) which inhibited cancer cells proliferation. For the first time, we have successfully developed DCA derived inhibitors that preferentially bind to the adenosine triphosphate (ATP) pocket of PDK isoform 1 (PDK1).

  15. Comparison of the novel vasodilator uridine triphosphate and adenosine for the measurement of fractional flow reserve

    DEFF Research Database (Denmark)

    Sivertsen, Jacob; Jensen, Jan Skov; Galatius, Søren;

    2014-01-01

    AIM: Examination of the fractional flow reserve (FFR) responses of intravenous (IV) adenosine with increasing doses of intracoronary (IC) adenosine versus IC uridine triphosphate (UTP) in patients with coronary artery disease. METHODS AND RESULTS: We measured FFR in 25 patients during continuous IV...... and IC infusion (using a microcatheter in the coronary ostium). Standard IV adenosine infusion (140 μg/kg/min) was compared to 8 equimolar incremental doses of IC UTP and IC adenosine (20, 40, 60, 80, 160, 240, 320 and 640 μg/min) in a randomized order. Across all doses, ΔFFR[IC UTP - IC adenosine......] was -0.038 ± 0.008, Pdose of IC UTP, FFR was significantly lower (FFR[IC UTP] = 0.62 ± 0.04) than during IV adenosine (FFR[IV adenosine] = 0.72 ± 0.05; P=.02) and IC adenosine (FFR[IC adenosine] = 0.68 ± 0.05; P=.03). Furthermore, UTP had significantly fewer side effects compared...

  16. Randomized clinical trial of adenosine 5'-triphosphate in patients with advanced non-small-cell lung cancer

    NARCIS (Netherlands)

    H.J. Agteresch; P.C. Dagnelie (Pieter); A. van der Gaast (Ate); Th. Stijnen (Theo); J.H.P. Wilson (Paul)

    2000-01-01

    textabstractBACKGROUND: Extracellular adenosine 5'-triphosphate (ATP) is involved in the regulation of a variety of biologic processes, including neurotransmission, muscle contraction, and liver glucose metabolism, via purinergic receptors. In nonrandomized studies invo

  17. Regulation of adenosine triphosphate-sensitive potassium channels suppresses the toxic effects of amyloid-beta peptide (25-35)

    Institute of Scientific and Technical Information of China (English)

    Min Kong; Maowen Ba; Hui Liang; Peng Shao; Tianxia Yu; Ying Wang

    2013-01-01

    In this study, we treated PC12 cells with 0-20 μM amyloid-β peptide (25-35) for 24 hours to induce cytotoxicity, and found that 5-20 μM amyloid-β peptide (25-35) decreased PC12 cell viability, but adenosine triphosphate-sensitive potassium channel activator diazoxide suppressed the decrease reactive oxygen species levels. These protective effects were reversed by the selective mitochondrial adenosine triphosphate-sensitive potassium channel blocker 5-hydroxydecanoate. An inducible nitric oxide synthase inhibitor, Nω-nitro-L-arginine, also protected PC12 cells from intracellular reactive oxygen species levels. However, the H2O2-degrading enzyme catalase could that the increases in both mitochondrial membrane potential and reactive oxygen species levels adenosine triphosphate-sensitive potassium channels and nitric oxide. Regulation of adenosine triphosphate-sensitive potassium channels suppresses PC12 cell cytotoxicity induced by amyloid-β

  18. Possible regulation of the Salmonella typhimurium histidine operon by adenosine triphosphate phosphoribosyltransferase: large metabolic effects.

    OpenAIRE

    Goitein, R K; Parsons, S. M.

    1980-01-01

    An effort to find growth conditions leading to conditional regulation of the histidine operon of Salmonella typhimurium by the allosteric first enzyme of the pathway, adenosine triphosphate phosphoribosyltransferase (EC 2.4.2.17), is reported. A strain deleting the enzyme, TR3343, behaved simply and predictably under all growth conditions, whereas histidine auxotrophs containing active enzyme behaved in complicated ways dependent upon the location of the histidine pathway lesion. hisE strains...

  19. Interaction of Divalent Metal Ions with the Adenosine Triphosphate Measured Using Nuclear Magnetic Resonance

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The interaction of adenosine triphosphate with divalent metal ions is important in biochemical functions. The effects of pH and metal ions Mg2+, Ca2+, Zn2+, Mn2+, and Co2+ on the chemical shift of the phosphate group of ATP have been studied using Nuclear Magnetic Resonance. The chemical shift of the β-phosphate of ATP is the most sensitive to pH. Ca2+ and Mg2+ bind with the α- and β-phosphate groups of ATP. Zn2+ binds to the adenosine ring hydrogen as well as to phosphate. The paramagnetic ions Mn2+ and Co2+ do not cause chemical shifts of the phosphate or proton peak. Mn2+ and Co2+ broaden the resonance peak only.

  20. Tween 20-stabilized gold nanoparticles combined with adenosine triphosphate-BODIPY conjugates for the fluorescence detection of adenosine with more than 1000-fold selectivity

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Szu-Ying; Shih, Ya-Chen [Department of Chemistry, National Sun Yat-sen University, Taiwan (China); Tseng, Wei-Lung, E-mail: tsengwl@mail.nsysu.edu.tw [Department of Chemistry, National Sun Yat-sen University, Taiwan (China); School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Taiwan (China); Center for Nanoscience and Nanotechnology, National Sun Yat-sen University, Taiwan (China); Center for Stem Cell Research, Kaohsiung Medical University, Taiwan (China)

    2015-02-01

    Graphical abstract: A simple, enzyme-free, label-free, sensitive and selective system was developed for detecting adenosine based on the use of Tween 20-stabilized gold nanoparticles as an efficient quencher for boron dipyrromethene-conjugated adenosine 5′-triphosphate and as a recognition element for adenosine. - Highlights: • The proposed method can detect adenosine with more than 1000-fold selectivity. • The analysis of adenosine is rapid (∼6 min) using the proposed method. • This method provided better sensitivity for adenosine as compared to aptamer-based sensors. • This method can be applied for the determination of adenosine in urine. - Abstract: This study describes the development of a simple, enzyme-free, label-free, sensitive, and selective system for detecting adenosine based on the use of Tween 20-stabilized gold nanoparticles (Tween 20-AuNPs) as an efficient fluorescence quencher for boron dipyrromethene-conjugated adenosine 5′-triphosphate (BODIPY-ATP) and as a recognition element for adenosine. BODIPY-ATP can interact with Tween 20-AuNPs through the coordination between the adenine group of BODIPY-ATP and Au atoms on the NP surface, thereby causing the fluorescence quenching of BODIPY-ATP through the nanometal surface energy transfer (NSET) effect. When adenosine attaches to the NP surface, the attached adenosine exhibits additional electrostatic attraction to BODIPY-ATP. As a result, the presence of adenosine enhances the efficiency of AuNPs in fluorescence quenching of BODIPY-ATP. The AuNP-induced fluorescence quenching of BODIPY-ATP progressively increased with an increase in the concentration of adenosine; the detection limit at a signal-to-noise ratio of 3 for adenosine was determined to be 60 nM. The selectivity of the proposed system was more than 1000-fold for adenosine over any adenosine analogs and other nucleotides. The proposed system combined with a phenylboronic acid-containing column was successfully applied to the

  1. Adenosine triphosphate concentration in relation to microbial biomass in aquatic systems

    Energy Technology Data Exchange (ETDEWEB)

    Cunningham, H.W. Jr.

    1977-01-01

    Analyses of adenosine triphosphate (ATP) extracted from a sediment community of an aquatic ecosystem by the sulfuric acid method are complicated by inhibitions from inorganic and organic compounds. Inhibitions by inorganic compounds are reversible while those by organic compounds are irreversible. The primary inhibition by organic compounds results by complexing with acid-soluble fulvic acids which will prevent the detection of as much as 80% of the ATP present in a sample by the luciferin-luciferase reaction. Analytical techniques were developed to partially circumvent such interferences. Biomass interpretations from ATP concentrations in aquatic systems are complicated by the diversity of the microbiota and by the variability in the carbon to ATP ratio caused by environmental conditions. However, when levels of ATP are considered as a physiological condition of a sedimentary community, this data provides a means to interpret community metabolism not available hitherto.

  2. Genetics and complementation of Haemophilus influenzae mutants deficient in adenosine 5'-triphosphate-dependent nuclease

    Energy Technology Data Exchange (ETDEWEB)

    Kooistra, J.; Small, G.D.; Setlow, J.K.; Shapanka, R.

    1976-04-01

    Eight different mutations in Haemophilus influenzae leading to deficiency in adenosine 5'-triphosphate (ATP)-dependent nuclease have been investigated in strains in which the mutations of the originally mutagenized strains have been transferred into the wild type. Sensitivity to mitomycin C and deoxycholate and complementation between extracts and deoxyribonucleic acid (DNA)-dependent ATPase activity have been measured. Genetic crosses have provided information on the relative position of the mutations on the genome. There are three complementation groups, corresponding to three genetic groups. The strains most sensitive to mitomycin and deoxycholate, derived from mutants originally selected on the basis of sensitivity to mitomycin C or methyl methanesulfonate, are in one group. Apparently all these sensitive strains lack DNA-dependent ATPase activity, as does a strain intermediate in sensitivity to deoxycholate, which is the sole representative of another group. There are four strains that are relatively resistant to deoxycholate and mitomycin C, and all of these contain the ATPase activity.

  3. Hybrid integrated biological-solid-state system powered with adenosine triphosphate

    Science.gov (United States)

    Roseman, Jared M.; Lin, Jianxun; Ramakrishnan, Siddharth; Rosenstein, Jacob K.; Shepard, Kenneth L.

    2015-12-01

    There is enormous potential in combining the capabilities of the biological and the solid state to create hybrid engineered systems. While there have been recent efforts to harness power from naturally occurring potentials in living systems in plants and animals to power complementary metal-oxide-semiconductor integrated circuits, here we report the first successful effort to isolate the energetics of an electrogenic ion pump in an engineered in vitro environment to power such an artificial system. An integrated circuit is powered by adenosine triphosphate through the action of Na+/K+ adenosine triphosphatases in an integrated in vitro lipid bilayer membrane. The ion pumps (active in the membrane at numbers exceeding 2 × 106 mm-2) are able to sustain a short-circuit current of 32.6 pA mm-2 and an open-circuit voltage of 78 mV, providing for a maximum power transfer of 1.27 pW mm-2 from a single bilayer. Two series-stacked bilayers provide a voltage sufficient to operate an integrated circuit with a conversion efficiency of chemical to electrical energy of 14.9%.

  4. Detection of adenosine triphosphate through polymerization-induced aggregation of actin-conjugated gold/silver nanorods

    Science.gov (United States)

    Liao, Yu-Ju; Shiang, Yen-Chun; Chen, Li-Yi; Hsu, Chia-Lun; Huang, Chih-Ching; Chang, Huan-Tsung

    2013-11-01

    We have developed a simple and selective nanosensor for the optical detection of adenosine triphosphate (ATP) using globular actin-conjugated gold/silver nanorods (G-actin-Au/Ag NRs). By simply mixing G-actin and Au/Ag NRs (length ˜56 nm and diameter ˜12 nm), G-actin-Au/Ag NRs were prepared which were stable in physiological solutions (25 mM Tris-HCl, 150 mM NaCl, 5.0 mM KCl, 3.0 mM MgCl2 and 1.0 mM CaCl2; pH 7.4). Introduction of ATP into the G-actin-Au/Ag NR solutions in the presence of excess G-actin induced the formation of filamentous actin-conjugated Au/Ag NR aggregates through ATP-induced polymerization of G-actin. When compared to G-actin-modified spherical Au nanoparticles having a size of 13 nm or 56 nm, G-actin-Au/Ag NRs provided better sensitivity for ATP, mainly because the longitudinal surface plasmon absorbance of the Au/Ag NR has a more sensitive response to aggregation. This G-actin-Au/Ag NR probe provided high sensitivity (limit of detection 25 nM) for ATP with remarkable selectivity (>10-fold) over other adenine nucleotides (adenosine, adenosine monophosphate and adenosine diphosphate) and nucleoside triphosphates (guanosine triphosphate, cytidine triphosphate and uridine triphosphate). It also allowed the determination of ATP concentrations in plasma samples without conducting tedious sample pretreatments; the only necessary step was simple dilution. Our experimental results are in good agreement with those obtained from a commercial luciferin-luciferase bioluminescence assay. Our simple, sensitive and selective approach appears to have a practical potential for the clinical diagnosis of diseases (e.g. cystic fibrosis) associated with changes in ATP concentrations.

  5. Diastolic Dysfunction Induced by a High-Fat Diet Is Associated with Mitochondrial Abnormality and Adenosine Triphosphate Levels in Rats

    OpenAIRE

    Kang, Ki-Woon; Kim, Ok-Soon; Chin, Jung Yeon; Kim, Won Ho; Park, Sang Hyun; Choi, Yu Jeong; Shin, Jong Ho; Jung, Kyung Tae; Lim, Do-Seon; Lee, Seong-Kyu

    2015-01-01

    Background Obesity is well-known as a risk factor for heart failure, including diastolic dysfunction. However, this mechanism in high-fat diet (HFD)-induced obese rats remain controversial. The purpose of this study was to investigate whether cardiac dysfunction develops when rats are fed with a HFD for 10 weeks; additionally, we sought to investigate the association between mitochondrial abnormalities, adenosine triphosphate (ATP) levels and cardiac dysfunction. Methods We examined myocardia...

  6. A Graphene and Aptamer Based Liquid Gated FET-Like Electrochemical Biosensor to Detect Adenosine Triphosphate.

    Science.gov (United States)

    Mukherjee, Souvik; Meshik, Xenia; Choi, Min; Farid, Sidra; Datta, Debopam; Lan, Yi; Poduri, Shripriya; Sarkar, Ketaki; Baterdene, Undarmaa; Huang, Ching-En; Wang, Yung Yu; Burke, Peter; Dutta, Mitra; Stroscio, Michael A

    2015-12-01

    Here we report successful demonstration of a FET-like electrochemical nano-biosensor to accurately detect ultralow concentrations of adenosine triphosphate. As a 2D material, graphene is a promising candidate due to its large surface area, biocompatibility, and demonstrated surface binding chemistries and has been employed as the conducting channel. A short 20-base DNA aptamer is used as the sensing element to ensure that the interaction between the analyte and the aptamer occurs within the Debye length of the electrolyte (PBS). Significant increase in the drain current with progressive addition of ATP is observed whereas for control experiments, no distinct change in the drain current occurs. The sensor is found to be highly sensitive in the nanomolar (nM) to micromolar ( μM) range with a high sensitivity of 2.55 μA (mM) (-1), a detection limit as low as 10 pM, and it has potential application in medical and biological settings to detect low traces of ATP. This simplistic design strategy can be further extended to efficiently detect a broad range of other target analytes.

  7. Leptin suppresses adenosine triphosphate-induced impairment of spinal cord astrocytes.

    Science.gov (United States)

    Li, Baoman; Qi, Shuang; Sun, Guangfeng; Yang, Li; Han, Jidong; Zhu, Yue; Xia, Maosheng

    2016-10-01

    Spinal cord injury (SCI) causes long-term disability and has no clinically effective treatment. After SCI, adenosine triphosphate (ATP) may be released from neuronal cells and astrocytes in large amounts. Our previous studies have shown that the extracellular release of ATP increases the phosphorylation of cytosolic phospholipase A2 (cPLA2 ) and triggers the rapid release of arachidonic acid (AA) and prostaglandin E2 (PGE2) via the stimulation of epidermal growth factor receptor (EGFR) and the downstream phosphorylation of extracellular-regulated protein kinases 1 and 2. Leptin, a glycoprotein, induces the activation of the Janus kinase (JAK2)/signal transducers and activators of transcription-3 (Stat3) pathway via the leptin receptor. In this study, we found that 1) prolonged leptin treatment suppressed the ATP-stimulated release of AA and PGE2 from cultured spinal cord astrocytes; 2) leptin elevated the expression of caveolin-1 (Cav-1) via the JAK2/Stat3 signaling pathway; 3) Cav-1 blocked the interaction between Src and EGFR, thereby inhibiting the phosphorylation of EGFR and cPLA2 and attenuating the release of AA or PGE2; 4) pretreatment with leptin decreased ;he level of apoptosis and the release of interleukin-6 from cocultured neurons and astrocytes; and 5) leptin improved the recovery of locomotion in mice after SCI. Our results highlight leptin as a promising therapeutic agent for SCI. © 2016 Wiley Periodicals, Inc. PMID:27316329

  8. The clinical value of adenosine triphosphate stress myocardial perfusion tomography for detecting coronary artery disease

    International Nuclear Information System (INIS)

    Objective: To study the clinical value of adenosine triphosphate stress myocardial perfusion tomography imaging (ATP-MPI) in detection of coronary artery disease (CAD). Methods: There were 278 patients underwent ATP-MPI, 51 patients of them also underwent coronary angiography (CAG). Seventy-three patients underwent stress-rest myocardial perfusion tomography imaging with multi-stage submaximal exercise test (ST-MPI) and CAG serving as control group. Results: 1) Side effects: there were 11 different symptoms and atrioventricular conduction block (10 patients), sinoatrial conduction block (2 patients) occurred during ATP stress. Allopathy or interruption of ATP stress did not happen. 2) The sensitivity and specificity of ATP-MPI in detection of CAD were 97.1% and 82.4%, respectively, and those in detection of ≥50% narrowing coronary artery were 91.0% and 94.7%, respectively. 3) In patients without myocardial infarction, the sensitivity and specificity of ATP-MPI in detection of myocardial ischemia were comparable to those of ST-MPI. Conclusion: ATP-MPI is an accurate, safe modality and is comparable to ST-MPI in the detection of CAD

  9. Measurement and interpretation of microbial adenosine tri-phosphate (ATP) in aquatic environments.

    Science.gov (United States)

    Hammes, Frederik; Goldschmidt, Felix; Vital, Marius; Wang, Yingying; Egli, Thomas

    2010-07-01

    There is a widespread need for cultivation-free methods to quantify viability of natural microbial communities in aquatic environments. Adenosine tri-phosphate (ATP) is the energy currency of all living cells, and therefore a useful indicator of viability. A luminescence-based ATP kit/protocol was optimised in order to detect ATP concentrations as low as 0.0001 nM with a standard deviation of water samples from a variety of aquatic environments (drinking water, groundwater, bottled water, river water, lake water and wastewater effluent) were analysed for extracellular ATP and microbial ATP in comparison with flow-cytometric (FCM) parameters. Microbial ATP concentrations ranged between 3% and 97% of total ATP concentrations, and correlated well (R(2)=0.8) with the concentrations of intact microbial cells (after staining with propidium iodide). From this correlation, we calculated an average ATP-per-cell value of 1.75x10(-10)nmol/cell. An even better correlation (R(2)=0.88) was observed between intact biovolume (derived from FCM scatter data) and microbial ATP concentrations, and an average ATP-per-biovolume value of 2.95x10(-9)nmol/microm(3) was calculated. These results support the use of ATP analysis for both routine monitoring and research purposes, and contribute towards a better interpretation of ATP data. PMID:20605621

  10. INHIBITORY EFFECTS OF ADENOSINE 5' -TRIPHOSPHATE ON COCHLEAR FUNCTION OF GUINEA PIG

    Institute of Scientific and Technical Information of China (English)

    杨军; 李吉平; 钱敏飞; 徐秀玲; 王家东; 丁大连

    2005-01-01

    Objective To study effects of adenosine 5'-triphosphate (ATP) on cochlear function of guinea pig. Methods After perfusion of ATP into perilymphatic spaces of the guinea pig cochlea, summating potential (SP), cochlear microphonic (CM) , auditory nerve compound action potential ( CAP ) , distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) were measured. Results The results showed concentration-dependent effect of ATP on the response alterations of bioelectric activity in cochlea. Administration of lmmol/L ATP caused an increase both in the amplitude of the SP and in the threshold of ABR, a decrease in amplitude of the CAP and DPOAE. In addition, response alterations of the CAP and DPOAE showed in an intensity- and frequency-dependent manner, respectively. At levels of 20 -70dB nHL sound intensity, lmmol/L ATP caused a significant decrease in the CAP amplitude, while at moderate and high frequency ranges of 2 -8kHz it reduced DPOAE amplitude significantly. 330μmol/L ATP also increased the threshold of ABR. Conclusion ATP through perilymphatic perfusion could inhibit cochlear function of guinea pig.

  11. Bond cleavages of adenosine 5'-triphosphate induced by monochromatic soft X-rays

    International Nuclear Information System (INIS)

    To investigate which type of bond is likely to be cleaved by soft X-ray exposure to an adenosine 5'-triphosphate (ATP), we observed spectral changes in X-ray absorption near edge structure (XANES) around nitrogen and oxygen K-edge of an ATP film by soft X-ray irradiation. Experiments were performed at a synchrotron soft X-ray beamline at SPring-8, Japan. The XANES spectra around the nitrogen and oxygen .K-edge slightly varied by exposure to 560 eV soft X-rays. These changes are originated from the cleavage of C-N bonds between a sugar and a nucleobase site and of C-O, P-O or O-H bond of sugar and phosphate site. From the comparison between the change in XANES intensity of σ* peak at nitrogen and that at oxygen K-edges, it is inferred that the C-O, P-O or O-H bond of sugar and phosphate is much efficiently cleaved than the C-N of N-glycoside bond by the exposure of 560 eV soft X-ray to ATP film.

  12. Amperometric biosensor system for simultaneous determination of adenosine-5'-triphosphate and glucose.

    Science.gov (United States)

    Kucherenko, Ivan S; Didukh, Daria Yu; Soldatkin, Oleksandr O; Soldatkin, Alexei P

    2014-06-01

    The majority of biosensors for adenosine-5'-triphosphate (ATP) determination are based on cascades of enzymatic reactions; therefore, they are sensitive to glucose or glycerol (depending on the enzymatic system) as well as to ATP. The presence of unknown concentrations of these substances in the sample greatly complicates the determination of ATP. To overcome this disadvantage of known biosensors, we developed a biosensor system consisting of two biosensors: the first one is based on glucose oxidase and is intended for measuring glucose concentration, and the second one is based on glucose oxidase and hexokinase and is sensitive toward both glucose and ATP. Using glucose concentration measured by the first biosensor, we can analyze the total response to glucose and ATP obtained by the second biosensor. Platinum disc electrodes were used as amperometric transducers. The polyphenilenediamine membrane was deposited onto the surface of platinum electrodes to avoid the response to electroactive substances. The effect of glucose concentration on biosensor determination of ATP was studied. The reproducibility of biosensor responses to glucose and ATP during a day was tested (relative standard deviation, RSD, of responses to glucose was 3-6% and to ATP was 8-12%) as well as storage stability of the biosensors (no decrease of glucose responses and 43% drop of ATP responses during 50 days). The measurements of ATP and glucose in pharmaceutical vials (including mixtures of ATP and glucose) were carried out. It was shown that the developed biosensor system can be used for simultaneous analysis of glucose and ATP concentrations in water solutions. PMID:24810180

  13. Adenosine 5′-Triphosphate Flux Through the North Inlet Marsh System †

    Science.gov (United States)

    Chrzanowski, Thomas H.; Stevenson, L. Harold; Kjerfve, Bjorn

    1979-01-01

    The distribution, fluctuation, and short-term transport of total microbial biomass (measured as adenosine 5′-triphosphate [ATP]) was investigated in a large salt marsh creek. Hourly samples were collected synoptically for 25 h from 10 boats positioned across the 320-m width of the creek. Samples were collected from three depths ranging from 0.2 to 8.0 m. Hourly data obtained from each station were graphed, plotting depth against ATP. Subsequently, interpolated ATP values were generated for every one-tenth depth from the surface to the bottom with the use of an 11-point proportional divider. A total of 2,750 values were generated, and a mean value of 0.865 mg of ATP per m3 was determined. Maximum levels of ATP were found at high tide and minimal values were found at low tide. The distribution of ATP concentrations was found to be complex, with no suggestion of vertical stratification; however, horizontal divisions were apparent. ATP values corrected for direction of flow or velocity indicated two ebb-directed channels; however, when considered in total, there was a net import of ATP through the interface. The total import of ATP for this 25-h sampling period was calculated to be 3.58 kg, corresponding to a net transport of 39.8 mg of ATP per s through the cross section. Results suggest that detailed characterization of a creek transect in terms of ATP or any similar parameter requires the simultaneous measurements of both the concentration of the parameter in question and the velocity at the time and point from which the sample was taken. PMID:16345382

  14. Adenosine-5'-triphosphate release by Mannheimia haemolytica, lipopolysaccharide, and interleukin-1 stimulated bovine pulmonary epithelial cells.

    Science.gov (United States)

    Craddick, Michael; Patel, Rakhi; Lower, Amanda; Highlander, Sarah; Ackermann, Mark; McClenahan, David

    2012-09-15

    Mannheimia haemolytica, one of the agents associated with bovine respiratory disease complex, can cause severe lung pathology including the leakage of vascular products into the airways and alveoli. Previous work by this laboratory has demonstrated that bovine lung endothelial and epithelial cells undergo dramatic permeability increases when exposed to adenosine-5'-triphosphate (ATP). Therefore, we wanted to determine if ATP levels were elevated in bronchoalveolar lavage (BAL) samples from calves experimentally infected with M. haemolytica. In addition, cultured bovine pulmonary epithelial (BPE) cells were stimulated with heat-killed and live M. haemolytica bacteria, lipopolysaccharide (LPS), lipoteichoic acid (LTA), interleukin-1 (IL-1), and zymosan activated plasma (ZAP) to determine whether they might release extracellular ATP during in vitro infection. Calves experimentally exposed to M. haemolytica had an approximately 2-fold higher level of ATP in their BAL samples compared to control. BPE cells exposed to increasing numbers of heat-killed or live M. haemolytica had significantly increased levels of ATP release as compared to time-matched controls. Finally, BPE cells treated with several concentrations of LPS and IL-1 had increases in ATP release as compared to time-matched controls. This increase appeared to be a result of active ATP secretion by the cells, as cell viability was similar between treated and non-treated cells. Neither ZAP nor LTA induced any ATP release by the cells. In conclusion, ATP levels are elevated in lung secretions from calves infected with M. haemolytica. In addition, lung epithelial cells can actively release ATP when exposed to heat-killed or live M. haemolytica, LPS or IL-1. PMID:22771196

  15. Dielectric spectra broadening as a signature for dipole-matrix interaction. III. Water in adenosine monophosphate/adenosine-5'-triphosphate solutions.

    Science.gov (United States)

    Puzenko, Alexander; Levy, Evgeniya; Shendrik, Andrey; Talary, Mark S; Caduff, Andreas; Feldman, Yuri

    2012-11-21

    In this, the third part of our series on the dielectric spectrum symmetrical broadening of water, we consider the nucleotide aqueous solutions. Where in Parts I [E. Levy et al., J. Chem. Phys. 136, 114502 (2012)] and II [E. Levy et al., J. Chem. Phys. 136, 114503 (2012)], the dipole-dipole or ion-dipole interaction had a dominant feature, now the interplay between these two types of dipole-matrix interactions will be considered. We present the results of high frequency dielectric measurements of different concentrations of adenosine monophosphate/adenosine-5'-triphosphate aqueous solutions. We observed the Cole-Cole broadening of the main relaxation peak of the solvent in the solutions. Moreover, depending on the nucleotide concentration, we observed both types of dipole-matrix interaction. The 3D trajectory approach (described in detail in Part I) is applied in order to highlight the differences between the two types of interaction.

  16. Dielectric spectra broadening as a signature for dipole-matrix interaction. III. Water in adenosine monophosphate/adenosine-5'-triphosphate solutions.

    Science.gov (United States)

    Puzenko, Alexander; Levy, Evgeniya; Shendrik, Andrey; Talary, Mark S; Caduff, Andreas; Feldman, Yuri

    2012-11-21

    In this, the third part of our series on the dielectric spectrum symmetrical broadening of water, we consider the nucleotide aqueous solutions. Where in Parts I [E. Levy et al., J. Chem. Phys. 136, 114502 (2012)] and II [E. Levy et al., J. Chem. Phys. 136, 114503 (2012)], the dipole-dipole or ion-dipole interaction had a dominant feature, now the interplay between these two types of dipole-matrix interactions will be considered. We present the results of high frequency dielectric measurements of different concentrations of adenosine monophosphate/adenosine-5'-triphosphate aqueous solutions. We observed the Cole-Cole broadening of the main relaxation peak of the solvent in the solutions. Moreover, depending on the nucleotide concentration, we observed both types of dipole-matrix interaction. The 3D trajectory approach (described in detail in Part I) is applied in order to highlight the differences between the two types of interaction. PMID:23181321

  17. Molecular structure of tetraaqua adenosine 5'-triphosphate aluminium(III) complex: A study involving Raman spectroscopy, theoretical DFT and potentiometry

    Science.gov (United States)

    Tenório, Thaís; Silva, Andréa M.; Ramos, Joanna Maria; Buarque, Camilla D.; Felcman, Judith

    2013-03-01

    The Alzheimer's disease is one of the most common neurodegenerative diseases that affect elderly population, due to the formation of β-amyloid protein aggregate and several symptoms, especially progressive cognitive decline. The result is a decrease in capture of glucose by cells leading to obliteration, meddling in the Krebs cycle, the principal biochemical route to the energy production leading to a decline in the levels of adenosine 5'-triphosphate. Aluminium(III) is connected to Alzheimer's and its ion provides raise fluidity of the plasma membrane, decrease cell viability and aggregation of amyloid plaques. Studies reveal that AlATP complex promotes the formation of reactive fibrils of β-amyloid protein and independent amyloidogenic peptides, suggesting the action of the complex as a chaperone in the role pathogenic process. In this research, one of complexes formed by Al(III) and adenosine 5'-triphosphate in aqueous solution is analyzed by potentiometry, Raman spectroscopy and ab initio calculations. The value of the log KAlATP found was 9.21 ± 0.01 and adenosine 5'-triphosphate should act as a bidentate ligand in the complex. Raman spectroscopy and potentiometry indicate that donor atoms are the oxygen of the phosphate β and the oxygen of the phosphate γ, the terminal phosphates. Computational calculations using Density Functional Theory, with hybrid functions B3LYP and 6-311++G(d,p) basis set regarding water solvent effects, have confirmed the results. Frontier molecular orbitals, electrostatic potential contour surface, electrostatic potential mapped and Mulliken charges of the title molecule were also investigated.

  18. Molecular structure of tetraaqua adenosine 5'-triphosphate aluminium(III) complex: a study involving Raman spectroscopy, theoretical DFT and potentiometry.

    Science.gov (United States)

    Tenório, Thaís; Silva, Andréa M; Ramos, Joanna Maria; Buarque, Camilla D; Felcman, Judith

    2013-03-15

    The Alzheimer's disease is one of the most common neurodegenerative diseases that affect elderly population, due to the formation of β-amyloid protein aggregate and several symptoms, especially progressive cognitive decline. The result is a decrease in capture of glucose by cells leading to obliteration, meddling in the Krebs cycle, the principal biochemical route to the energy production leading to a decline in the levels of adenosine 5'-triphosphate. Aluminium(III) is connected to Alzheimer's and its ion provides raise fluidity of the plasma membrane, decrease cell viability and aggregation of amyloid plaques. Studies reveal that AlATP complex promotes the formation of reactive fibrils of β-amyloid protein and independent amyloidogenic peptides, suggesting the action of the complex as a chaperone in the role pathogenic process. In this research, one of complexes formed by Al(III) and adenosine 5'-triphosphate in aqueous solution is analyzed by potentiometry, Raman spectroscopy and ab initio calculations. The value of the logK(AlATP) found was 9.21±0.01 and adenosine 5'-triphosphate should act as a bidentate ligand in the complex. Raman spectroscopy and potentiometry indicate that donor atoms are the oxygen of the phosphate β and the oxygen of the phosphate γ, the terminal phosphates. Computational calculations using Density Functional Theory, with hybrid functions B3LYP and 6-311++G(d,p) basis set regarding water solvent effects, have confirmed the results. Frontier molecular orbitals, electrostatic potential contour surface, electrostatic potential mapped and Mulliken charges of the title molecule were also investigated.

  19. An improved red blood cell additive solution maintains 2,3-diphosphoglycerate and adenosine triphosphate levels by an enhancing effect on phosphofructokinase activity during cold storage

    NARCIS (Netherlands)

    P. Burger; H. Korsten; D. de Korte; E. Rombout; R. van Bruggen; A.J. Verhoeven

    2010-01-01

    BACKGROUND: Current additive solutions (ASs) for red blood cells (RBCs) do not maintain constant 2,3-diphosphoglycerate (DPG) and adenosine triphosphate (ATP) levels during cold storage We have previously shown that with a new AS called phosphate-adenine-glucose-guanosine-gluconate-mannitol (PAGGGM)

  20. Plaque retention by self-ligating vs elastomeric orthodontic brackets: quantitative comparison of oral bacteria and detection with adenosine triphosphate-driven bioluminescence.

    NARCIS (Netherlands)

    Pellegrini, P.; Sauerwein, R.W.; Finlayson, T.; McLeod, J.; Covell, D.A.; Maier, T.; Machida, C.A.

    2009-01-01

    INTRODUCTION: Enamel decalcification is a common problem in orthodontics. The objectives of this randomized clinical study were to enumerate and compare plaque bacteria surrounding 2 bracket types, self-ligating (SL) vs elastomeric ligating (E), and to determine whether adenosine triphosphate (ATP)-

  1. Sterol transporter adenosine triphosphate-binding cassette transporter G8, gallstones, and biliary cancer in 62,000 individuals from the general population

    DEFF Research Database (Denmark)

    Stender, Stefan; Frikke-Schmidt, Ruth; Nordestgaard, Børge G;

    2011-01-01

    Gallstone disease, a risk factor for biliary cancer, has a strong heritable component, but the underlying genes are largely unknown. To test the hypothesis that ABCG8 (adenosine triphosphate-binding cassette transporter G8) Asp19His (D19H) genotype predicted risk of gallstones and biliary cancer ...

  2. Adenosine 5 '-triphosphate (ATP) supplements are not orally bioavailable: a randomized, placebo-controlled cross-over trial in healthy humans

    NARCIS (Netherlands)

    Arts, I.C.W.; Coolen, E.J.C.M.; Bours, M.J.L.; Huyghebaert, N.; Cohen Stuart, M.A.; Bast, A.; Dagnelie, P.C.

    2012-01-01

    Background: Nutritional supplements designed to increase adenosine 5'-triphosphate (ATP) concentrations are commonly used by athletes as ergogenic aids. ATP is the primary source of energy for the cells, and supplementation may enhance the ability to maintain high ATP turnover during high-intensity

  3. A rapid method for the determination of microbial susceptibility using the firefly luciferase assay for adenosine triphosphate (ATP)

    Science.gov (United States)

    Vellend, H.; Tuttle, S. A.; Barza, M.; Weinstein, L.; Picciolo, G. L.; Chappelle, E. W.

    1975-01-01

    Luciferase assay for adenosine triphosphate (ATP) was optimized for pure bacteria in broth in order to evaluate if changes in bacterial ATP content could be used as a rapid measure of antibiotic effect on microorganisms. Broth cultures of log phase bacteria were incubated at 310 K (37 C) for 2.5 hours at antimicrobial concentrations which resulted in the best discrimination between sensitive and resistant strains. Eighty-seven strains of 11 bacterial species were studied for their susceptibility to 12 commonly used antimicrobial agents: ampicillin, Penicillin G, nafcillin, carbenicillin, cephalothin, tetracycline, erythromycin, clindamycin, gentamicin, nitrofurantoin, colistin, and chloramplenicol. The major advantage of the ATP system over existing methods of rapid microbial susceptibility testing is that the assay can be made specific for bacterial ATP.

  4. Evidence for a "metabolically inactive" inorganic phosphate pool in adenosine triphosphate synthase reaction using localized 31P saturation transfer magnetic resonance spectroscopy in the rat brain at 11.7 T.

    Science.gov (United States)

    Tiret, Brice; Brouillet, Emmanuel; Valette, Julien

    2016-09-01

    With the increased spectral resolution made possible at high fields, a second, smaller inorganic phosphate resonance can be resolved on (31)P magnetic resonance spectra in the rat brain. Saturation transfer was used to estimate de novo adenosine triphosphate synthesis reaction rate. While the main inorganic phosphate pool is used by adenosine triphosphate synthase, the second pool is inactive for this reaction. Accounting for this new pool may not only help us understand (31)P magnetic resonance spectroscopy metabolic profiles better but also better quantify adenosine triphosphate synthesis.

  5. A modified method for synthesis of [γ-32P] labelled adenosine triphosphate

    International Nuclear Information System (INIS)

    Production of [γ-32P]-ATP using three glycolysis enzymatic reaction i.e. glyceraldehyde 3-phosphate dehydrogenase, 3-phosphoglyceric phosphokinase and lactate dehydrogenase has been conducted. dl-glyceraldehyde 3-phosphate, Adenosine Diphosphate and H332PO4 was used as precursors for this reaction. Purification of [γ-32P]-ATP was performed by using DEAE-Sephadex column chromatography. The result suggested that this simple method could be used for producing [γ-32P]-ATP to support the provision of radiolabeled nucleotide for biotechnology research in Indonesia. (author)

  6. Application of Adenosine Triphosphate Affinity Probe and Scheduled Multiple-Reaction Monitoring Analysis for Profiling Global Kinome in Human Cells in Response to Arsenite Treatment

    OpenAIRE

    Guo, Lei; Xiao, Yongsheng; Wang, Yinsheng

    2014-01-01

    Phosphorylation of cellular components catalyzed by kinases plays important roles in cell signaling and proliferation. Quantitative assessment of perturbation in global kinome may provide crucial knowledge for elucidating the mechanisms underlying the cytotoxic effects of environmental toxicants. Here, we utilized an adenosine triphosphate (ATP) affinity probe coupled with stable isotope labeling by amino acids in cell culture (SILAC) to assess quantitatively the arsenite-induced alteration o...

  7. Adenosine 5 '-triphosphate (ATP) supplements are not orally bioavailable: a randomized, placebo-controlled cross-over trial in healthy humans

    OpenAIRE

    Arts Ilja CW; Coolen Erik JCM; Bours Martijn JL; Huyghebaert Nathalie; Stuart Martien A; Bast Aalt; Dagnelie Pieter C

    2012-01-01

    Abstract Background Nutritional supplements designed to increase adenosine 5′-triphosphate (ATP) concentrations are commonly used by athletes as ergogenic aids. ATP is the primary source of energy for the cells, and supplementation may enhance the ability to maintain high ATP turnover during high-intensity exercise. Oral ATP supplements have beneficial effects in some but not all studies examining physical performance. One of the remaining questions is whether orally administered ATP is bioav...

  8. Utilization of adenosine triphosphate in rat mast cells during histamine release induced by the ionophore A23187

    DEFF Research Database (Denmark)

    Johansen, Torben

    1979-01-01

    The role of endogenous adenosine triphosphate (ATP) in histamine release from rat mast cells induced by the ionophore A23187 in vitro has been studied. 2 The amount of histamine released by calcium from rat mast cells primed with the ionophore A23187 was dependent on the ATP content of the mast c...... cells. 3 In aerobic experiments a drastic reduction in mast cell ATP content was found during the time when histamine release induced by A23187 takes place. 4 Anaerobic experiments were performed with metabolic inhibitors (antimycin A, oligomycin, and carbonyl cyanide p......-trifluorometroxyphenylnydrazone), which are known to block the energy-dependent calcium uptake by isolated mitochondria. The mast cell ATP content was reduced during A23187-induced histamine release under anaerobic conditions in the presence of glucose. This indicates an increased utilization of ATP during the release process. 5...... The observations are consistent with the view that energy requiring processes are involved in ionophore-induced histamine release from rat mast cells although part of the ATP reduction in the aerobic experiments may be due to an uncoupling effect of calcium on the oxidative phosphorylation....

  9. Diagnostic value of adenosine-triphosphate radionuclide ventriculography in coronary artery disease. Comparison with conventional exercise stress method

    International Nuclear Information System (INIS)

    The purpose of this study was to assess the effect of adenosine-triphosphate (ATP) on hemodynamics and left ventricular (LV) function, and to examine the value of ATP radionuclide-ventriculography (RNVG) for detecting coronary artery disease (CAD) in comparison with standard exercise RNVG. Thirty-eight consecutive patients with suspected CAD underwent ATP (0.18 mg/Kg/min) RNVG and symptom-limited exercise RNVG. Coronary angiography revealed 27 patients with CAD (Group S) and 11 without CAD (Group N). In group S, exercise induced an increase in LV end-diastolic volume (LVEDV) and LV end-systolic volume (LVESV), and a decrease in LV ejection fraction (LVEF). In contrast, ATP infusion caused LVESV to decrease in both groups, improving LVEF. Only 14 of 39 segments whose wall motion was deteriorated by exercise showed worsening regional wall motion during ATP infusion. The sensitivity and specificity of ATP RNVG for detecting CAD were 22. 2% and 100%, while those of exercise RNVG were 77.8% and 81.8%, respectively. Although ATP induced a depression of peak filling rate in group S as compared with group N, the deterioration of systolic function was not apparent with this method. ATP RNVG was not adequate for detecting CAD because of its lower sensitivity compared with exercise RNVG. (author)

  10. Calcium and adenosine triphosphate control of cellular pathology: asparaginase-induced pancreatitis elicited via protease-activated receptor 2.

    Science.gov (United States)

    Peng, Shuang; Gerasimenko, Julia V; Tsugorka, Tatiana; Gryshchenko, Oleksiy; Samarasinghe, Sujith; Petersen, Ole H; Gerasimenko, Oleg V

    2016-08-01

    Exocytotic secretion of digestive enzymes from pancreatic acinar cells is elicited by physiological cytosolic Ca(2+) signals, occurring as repetitive short-lasting spikes largely confined to the secretory granule region, that stimulate mitochondrial adenosine triphosphate (ATP) production. By contrast, sustained global cytosolic Ca(2+) elevations decrease ATP levels and cause necrosis, leading to the disease acute pancreatitis (AP). Toxic Ca(2+) signals can be evoked by products of alcohol and fatty acids as well as bile acids. Here, we have investigated the mechanism by which l-asparaginase evokes AP. Asparaginase is an essential element in the successful treatment of acute lymphoblastic leukaemia, the most common type of cancer affecting children, but AP is a side-effect occurring in about 5-10% of cases. Like other pancreatitis-inducing agents, asparaginase evoked intracellular Ca(2+) release followed by Ca(2+) entry and also substantially reduced Ca(2+) extrusion because of decreased intracellular ATP levels. The toxic Ca(2+) signals caused extensive necrosis. The asparaginase-induced pathology depended on protease-activated receptor 2 and its inhibition prevented the toxic Ca(2+) signals and necrosis. We tested the effects of inhibiting the Ca(2+) release-activated Ca(2+) entry by the Ca(2+) channel inhibitor GSK-7975A. This markedly reduced asparaginase-induced Ca(2+) entry and also protected effectively against the development of necrosis.This article is part of the themed issue 'Evolution brings Ca(2+) and ATP together to control life and death'. PMID:27377732

  11. Campylobacter jejuni adenosine triphosphate phosphoribosyltransferase is an active hexamer that is allosterically controlled by the twisting of a regulatory tail.

    Science.gov (United States)

    Mittelstädt, Gerd; Moggré, Gert-Jan; Panjikar, Santosh; Nazmi, Ali Reza; Parker, Emily J

    2016-08-01

    Adenosine triphosphate phosphoribosyltransferase (ATP-PRT) catalyzes the first committed step of the histidine biosynthesis in plants and microorganisms. Here, we present the functional and structural characterization of the ATP-PRT from the pathogenic ε-proteobacteria Campylobacter jejuni (CjeATP-PRT). This enzyme is a member of the long form (HisGL ) ATP-PRT and is allosterically inhibited by histidine, which binds to a remote regulatory domain, and competitively inhibited by AMP. In the crystalline form, CjeATP-PRT was found to adopt two distinctly different hexameric conformations, with an open homohexameric structure observed in the presence of substrate ATP, and a more compact closed form present when inhibitor histidine is bound. CjeATP-PRT was observed to adopt only a hexameric quaternary structure in solution, contradicting previous hypotheses favoring an allosteric mechanism driven by an oligomer equilibrium. Instead, this study supports the conclusion that the ATP-PRT long form hexamer is the active species; the tightening of this structure in response to remote histidine binding results in an inhibited enzyme. PMID:27191057

  12. Influence of Thromboxane A2 on the Regulation of Adenosine Triphosphate-Sensitive Potassium Channels in Mouse Ventricular Myocytes

    Science.gov (United States)

    Jeong, In Seok; Cho, Hwa Jin; Cho, Jeong Gwan; Kim, Sang Hyung; Na, Kook Joo

    2016-01-01

    Background and Objectives Adenosine triphosphate (ATP)-sensitive potassium (KATP) channels play an important role in myocardial protection. We examined the effects of thromboxane A2 on the regulation of KATP channel activity in single ventricular myocytes. Subjects and Methods Single ventricular myocytes were isolated from the hearts of adult Institute of Cancer Research (ICR) mice by enzymatic digestion. Single channel activity was recorded by excised inside-out and cell-attached patch clamp configurations at −60 mV holding potential during the perfusion of an ATP-free K-5 solution. Results In the excised inside-out patches, the thromboxane A2 analog, U46619, decreased the KATP channel activity in a dose-dependent manner; however, the thromboxane A2 receptor antagonist, SQ29548, did not significantly attenuate the inhibitory effect of U46619. In the cell-attached patches, U46619 inhibited dinitrophenol (DNP)-induced KATP channel activity in a dose-dependent manner, and SQ29548 attenuated the inhibitory effects of U46619 on DNP-induced KATP channel activity. Conclusion Thromboxane A2 may inhibit KATP channel activity, and may have a harmful effect on ischemic myocardium. PMID:27482267

  13. Calcium and adenosine triphosphate control of cellular pathology: asparaginase-induced pancreatitis elicited via protease-activated receptor 2

    Science.gov (United States)

    Peng, Shuang; Gerasimenko, Julia V.; Tsugorka, Tatiana; Gryshchenko, Oleksiy; Samarasinghe, Sujith; Gerasimenko, Oleg V.

    2016-01-01

    Exocytotic secretion of digestive enzymes from pancreatic acinar cells is elicited by physiological cytosolic Ca2+ signals, occurring as repetitive short-lasting spikes largely confined to the secretory granule region, that stimulate mitochondrial adenosine triphosphate (ATP) production. By contrast, sustained global cytosolic Ca2+ elevations decrease ATP levels and cause necrosis, leading to the disease acute pancreatitis (AP). Toxic Ca2+ signals can be evoked by products of alcohol and fatty acids as well as bile acids. Here, we have investigated the mechanism by which l-asparaginase evokes AP. Asparaginase is an essential element in the successful treatment of acute lymphoblastic leukaemia, the most common type of cancer affecting children, but AP is a side-effect occurring in about 5–10% of cases. Like other pancreatitis-inducing agents, asparaginase evoked intracellular Ca2+ release followed by Ca2+ entry and also substantially reduced Ca2+ extrusion because of decreased intracellular ATP levels. The toxic Ca2+ signals caused extensive necrosis. The asparaginase-induced pathology depended on protease-activated receptor 2 and its inhibition prevented the toxic Ca2+ signals and necrosis. We tested the effects of inhibiting the Ca2+ release-activated Ca2+ entry by the Ca2+ channel inhibitor GSK-7975A. This markedly reduced asparaginase-induced Ca2+ entry and also protected effectively against the development of necrosis. This article is part of the themed issue ‘Evolution brings Ca2+ and ATP together to control life and death’. PMID:27377732

  14. Serine-324 of myosin's heavy chain is photoaffinity-labeled by 3'(2')-O-(4-benzoylbenzoyl)adenosine triphosphate

    International Nuclear Information System (INIS)

    A portion of the active site of rabbit skeletal myosin near the ribose ring of ATP can be labeled by the photoaffinity analogue 3'(2')-O-(4-benzoylbenzoyl)adenosine triphosphate (Bz2ATP). The specificity of the photolabeling was assured by first trapping [14C]Bz2ATP at the active site by use of thiol cross-linking agents. Five radioactive peptides were isolated by high-performance liquid chromatography after extensive trypsin and subtilisin digestion of photolabeled myosin subfragment 1. Four of these peptides were sequenced by Edman techniques, and all originated from a region with the sequence Gly-Glu-Ile-Thr-Val-Pro-Ser-Ile-Asp-Asp-Gln, which corresponds to rabbit myosin heavy chain residues 312-328. The fifth labeled peptide had an amino acid composition appropriate for residues 312-328. Amino acid composition, radiochemical analysis, and sequence data indicate that Ser-324 is the major amino acid residue photolabeled by Bz2ATP. Spectrophotometric evidence indicates that the benzophenone carbonyl group has inserted into a C-H bond from either the α- or β-carbon of serine. These results place Ser-324 at a distance of 6-7 angstrom from the 3'(2') ribose oxygens of ATP bound at the active site of myosin

  15. Supplementation of exogenous adenosine 5'-triphosphate enhances mechanical properties of 3D cell-agarose constructs for cartilage tissue engineering.

    Science.gov (United States)

    Gadjanski, Ivana; Yodmuang, Supansa; Spiller, Kara; Bhumiratana, Sarindr; Vunjak-Novakovic, Gordana

    2013-10-01

    Formation of tissue-engineered cartilage is greatly enhanced by mechanical stimulation. However, direct mechanical stimulation is not always a suitable method, and the utilization of mechanisms underlying mechanotransduction might allow for a highly effective and less aggressive alternate means of stimulation. In particular, the purinergic, adenosine 5'-triphosphate (ATP)-mediated signaling pathway is strongly implicated in mechanotransduction within the articular cartilage. We investigated the effects of transient and continuous exogenous ATP supplementation on mechanical properties of cartilaginous constructs engineered using bovine chondrocytes and human mesenchymal stem cells (hMSCs) encapsulated in an agarose hydrogel. For both cell types, we have observed significant increases in equilibrium and dynamic compressive moduli after transient ATP treatment applied in the fourth week of cultivation. Continuous ATP treatment over 4 weeks of culture only slightly improved the mechanical properties of the constructs, without major changes in the total glycosaminoglycan (GAG) and collagen content. Structure-function analyses showed that transiently ATP-treated constructs, and in particular those based on hMSCs, had the highest level of correlation between compositional and mechanical properties. Transiently treated groups showed intense staining of the territorial matrix for GAGs and collagen type II. These results indicate that transient ATP treatment can improve functional mechanical properties of cartilaginous constructs based on chondrogenic cells and agarose hydrogels, possibly by improving the structural organization of the bulk phase and territorial extracellular matrix (ECM), that is, by increasing correlation slopes between the content of the ECM components (GAG, collagen) and mechanical properties of the construct.

  16. Adenosine triphosphate-competitive mTOR inhibitors: a new class of immunosuppressive agents that inhibit allograft rejection.

    Science.gov (United States)

    Rosborough, B R; Raïch-Regué, D; Liu, Q; Venkataramanan, R; Turnquist, H R; Thomson, A W

    2014-09-01

    The mechanistic/mammalian target of rapamycin (mTOR) is inhibited clinically to suppress T cell function and prevent allograft rejection. mTOR is the kinase subunit of two mTOR-containing complexes, mTOR complex (mTORC) 1 and 2. Although mTORC1 is inhibited by the macrolide immunosuppressant rapamycin (RAPA), its efficacy may be limited by its inability to block mTORC1 completely and its limited effect on mTORC2. Adenosine triphosphate (ATP)-competitive mTOR inhibitors are an emerging class of mTOR inhibitors that compete with ATP at the mTOR active site and inhibit any mTOR-containing complex. Since this class of compounds has not been investigated for their immunosuppressive potential, our goal was to determine the influence of a prototypic ATP-competitive mTOR inhibitor on allograft survival. AZD8055 proved to be a potent suppressor of T cell proliferation. Moreover, a short, 10-day course of the agent successfully prolonged murine MHC-mismatched, vascularized heart transplant survival. This therapeutic effect was associated with increased graft-infiltrating regulatory T cells and reduced CD4(+) and CD8(+) T cell interferon-γ production. These studies establish for the first time, that ATP-competitive mTOR inhibition can prolong organ allograft survival and warrant further investigation of this next generation mTOR inhibitors. PMID:25307040

  17. Adenosine Triphosphate (ATP Is a Candidate Signaling Molecule in the Mitochondria-to-Nucleus Retrograde Response Pathway

    Directory of Open Access Journals (Sweden)

    Zhengchang Liu

    2013-03-01

    Full Text Available Intracellular communication from the mitochondria to the nucleus is achieved via the retrograde response. In budding yeast, the retrograde response, also known as the RTG pathway, is regulated positively by Rtg1, Rtg2, Rtg3 and Grr1 and negatively by Mks1, Lst8 and two 14-3-3 proteins, Bmh1/2. Activation of retrograde signaling leads to activation of Rtg1/3, two basic helix-loop-helix leucine zipper transcription factors. Rtg1/3 activation requires Rtg2, a cytoplasmic protein with an N-terminal adenosine triphosphate (ATP binding domain belonging to the actin/Hsp70/sugar kinase superfamily. The critical regulatory step of the retrograde response is the interaction between Rtg2 and Mks1. Rtg2 binds to and inactivates Mks1, allowing for activation of Rtg1/3 and the RTG pathway. When the pathway is inactive, Mks1 has dissociated from Rtg2 and bound to Bmh1/2, preventing activation of Rtg1/3. What signals association or disassociation of Mks1 and Rtg2 is unknown. Here, we show that ATP at physiological concentrations dissociates Mks1 from Rtg2 in a highly cooperative fashion. We report that ATP-mediated dissociation of Mks1 from Rtg2 is conserved in two other fungal species, K. lactis and K. waltii. Activation of Rtg1/3 upregulates expression of genes encoding enzymes catalyzing the first three reactions of the Krebs cycle, which is coupled to ATP synthesis through oxidative phosphorylation. Therefore, we propose that the retrograde response is an ATP homeostasis pathway coupling ATP production with ATP-mediated repression of the retrograde response by releasing Mks1 from Rtg2.

  18. A cascade amplification strategy based on rolling circle amplification and hydroxylamine amplified gold nanoparticles enables chemiluminescence detection of adenosine triphosphate.

    Science.gov (United States)

    Wang, Ping; Zhang, Tonghuan; Yang, Taoyi; Jin, Nan; Zhao, Yanjun; Fan, Aiping

    2014-08-01

    A highly sensitive and selective chemiluminescent (CL) biosensor for adenosine triphosphate (ATP) was developed by taking advantage of the ATP-dependent enzymatic reaction (ATP-DER), the powerful signal amplification capability of rolling circle amplification (RCA), and hydroxylamine-amplified gold nanoparticles (Au NPs). The strategy relies on the ability of ATP, a cofactor of T4 DNA ligase, to trigger the ligation-RCA reaction. In the presence of ATP, the T4 DNA ligase catalyzes the ligation reaction between the two ends of the padlock probe, producing a closed circular DNA template that initiates the RCA reaction with phi29 DNA polymerase and dNTP. Therein, many complementary copies of the circular template can be generated. The ATP-DER is eventually converted into a detectable CL signal after a series of processes, including gold probe hybridization, hydroxylamine amplification, and oxidative gold metal dissolution coupled with a simple and sensitive luminol CL reaction. The CL signal is directly proportional to the ATP level. The results showed that the detection limit of the assay is 100 pM of ATP, which compares favorably with those of other ATP detection techniques. In addition, by taking advantage of ATP-DER, the proposed CL sensing system exhibits extraordinary specificity towards ATP and could distinguish the target molecule ATP from its analogues. The proposed method provides a new and versatile platform for the design of novel DNA ligation reaction-based CL sensing systems for other cofactors. This novel ATP-DER based CL sensing system may find wide applications in clinical diagnosis as well as in environmental and biomedical fields.

  19. Preferential binding of Escherichia coli RecF protein to gapped DNA in the presence of adenosine (gamma-thio) triphosphate.

    OpenAIRE

    Hegde, S P; Rajagopalan, M; Madiraju, M V

    1996-01-01

    Escherichia coli RecF protein binds, but does not hydrolyze, ATP. To determine the role that ATP binding to RecF plays in RecF protein-mediated DNA binding, we have determined the interaction between RecF protein and single-stranded (ss)DNA, double-stranded (ds)DNA, and dsDNA containing ssDNA regions (gapped [g]DNA) either alone or in various combinations both in the presence and in the absence of adenosine (gamma-thio) triphosphate, gamma-S-ATP, a nonhydrolyzable ATP analog. Protein-DNA comp...

  20. Comparison of plate counts, Petrifilm, dipslides, and adenosine triphosphate bioluminescence for monitoring bacteria in cooling-tower waters.

    Science.gov (United States)

    Mueller, Sherry A; Anderson, James E; Kim, Byung R; Ball, James C

    2009-04-01

    Effective bacterial control in cooling-tower systems requires accurate and timely methods to count bacteria. Plate-count methods are difficult to implement on-site, because they are time- and labor-intensive and require sterile techniques. Several field-applicable methods (dipslides, Petrifilm, and adenosine triphosphate [ATP] bioluminescence) were compared with the plate count for two sample matrices--phosphate-buffered saline solution containing a pure culture of Pseudomonas fluorescens and cooling-tower water containing an undefined mixed bacterial culture. For the pure culture, (1) counts determined on nutrient agar and plate-count agar (PCA) media and expressed as colony-forming units (CFU) per milliliter were equivalent to those on R2A medium (p = 1.0 and p = 1.0, respectively); (2) Petrifilm counts were not significantly different from R2A plate counts (p = 0.99); (3) the dipslide counts were up to 2 log units higher than R2A plate counts, but this discrepancy was not statistically significant (p = 0.06); and (4) a discernable correlation (r2 = 0.67) existed between ATP readings and plate counts. For cooling-tower water samples (n = 62), (1) bacterial counts using R2A medium were higher (but not significant; p = 0.63) than nutrient agar and significantly higher than tryptone-glucose yeast extract (TGE; p = 0.03) and PCA (p < 0.001); (2) Petrifilm counts were significantly lower than nutrient agar or R2A (p = 0.02 and p < 0.001, respectively), but not statistically different from TGE, PCA, and dipslides (p = 0.55, p = 0.69, and p = 0.91, respectively); (3) the dipslide method yielded bacteria counts 1 to 3 log units lower than nutrient agar and R2A (p < 0.001), but was not significantly different from Petrifilm (p = 0.91), PCA (p = 1.00) or TGE (p = 0.07); (4) the differences between dipslides and the other methods became greater with a 6-day incubation time; and (5) the correlation between ATP readings and plate counts varied from system to system, was poor

  1. Radioimmunoassay for guanosin-5'-diphosphate-3'-diphosphate and adenosine-5'-triphosphate-3'-diphosphate

    Energy Technology Data Exchange (ETDEWEB)

    Hamagishi, Y.; Oki, T.; Tone, H.; Inui, T. (Sanraku-Ocean Co. Ltd., Fujisawa, Kanagawa (Japan). Central Research Lab.)

    1980-12-01

    A radioimmunoassay for guanosine-5'-diphosphate-3'-diphosphate (ppGpp) and adenosine-5'-triphosphate-3'-diphosphate (pppApp) has been developed. The assay method is based on competition of an unlabeled highly phosphorylated nucleotide with /sup 3/H-labeled highly phosphorylated nucleotide for binding sites on a specific antibody. Antibodies to ppGpp and pppApp were obtained by immunizing rabbits with the antigen prepared by conjugating ppGpp with human serum albumin using 1-ethyl-3-(3-dimethylaminoprophyl)carbodiimide, and with the antigen prepared by conjugating 8-(6-aminohexyl)amino-adenosine-5'-triphosphate-3'-diphosphate with human serum albumin using glutaraldehyde, respectively. Antibody-bound /sup 3/H-labeled highly phosphorylated nucleotides were separated from the free /sup 3/H-labeled highly phosphorylated nucleotides by selective adsorption on dextran-coated charcoal. Displacement plots were linear over a concentration range of 5 - 1,000 pmol/assay tube in a log-probit percentage plot. Application of this method to biological systems offers improved accuracy and convenience compared with the previous /sup 32/PO/sub 4/-labeling technique.

  2. Effects of oral adenosine 5'-triphosphate and adenosine in enteric-coated capsules on indomethacin-induced permeability changes in the human small intestine: a randomized cross-over study

    Directory of Open Access Journals (Sweden)

    Bours Martijn JL

    2007-06-01

    Full Text Available Abstract Background It is well-known that nonsteroidal anti-inflammatory drugs (NSAIDs can cause damage to the small bowel associated with disruption of mucosal barrier function. In healthy human volunteers, we showed previously that topical administration of adenosine 5'-triphosphate (ATP by naso-intestinal tube attenuated a rise in small intestinal permeability induced by short-term challenge with the NSAID indomethacin. This finding suggested that ATP may be involved in the preservation of intestinal barrier function. Our current objective was to corroborate the favourable effect of ATP on indomethacin-induced permeability changes in healthy human volunteers when ATP is administered via enteric-coated capsules, which is a more practically feasible mode of administration. Since ATP effects may have been partly mediated through its breakdown to adenosine, effects of encapsulated adenosine were tested also. Methods By ingesting a test drink containing 5 g lactulose and 0.5 g L-rhamnose followed by five-hour collection of total urine, small intestinal permeability was assessed in 33 healthy human volunteers by measuring the urinary lactulose/rhamnose excretion ratio. Urinary excretion of lactulose and L-rhamnose was determined by fluorescent detection high-pressure liquid chromatography (HPLC. Basal permeability of the small intestine was assessed as a control condition (no indomethacin, no ATP/adenosine. As a model of increased small intestinal permeability, two dosages of indomethacin were ingested at 10 h (75 mg and 1 h (50 mg before ingesting the lactulose/rhamnose test drink. At 1.5 h before indomethacin ingestion, two dosages of placebo, ATP (2 g per dosage or adenosine (1 g per dosage were administered via enteric-coated hydroxypropyl methylcellulose (HPMC capsules with Eudragit© L30D-55. Results Median urinary lactulose/rhamnose excretion ratio (g/g in the control condition was 0.032 (interquartile range: 0.022–0.044. Compared to the

  3. Macroscopic and Fluorescent Discrimination of Adenosine Triphosphate via Selective Metallo-hydrogel Formation: A Visual, Practical, and Reliable Rehearsal toward Cellular Imaging.

    Science.gov (United States)

    Fang, Weiwei; Liu, Cong; Yu, Fabiao; Liu, Yaoqi; Li, Zhenhua; Chen, Lingxin; Bao, Xiaoling; Tu, Tao

    2016-08-17

    With use of simple terpyridine zinc nitrate complexes, intriguing visual recognition of adenosine triphosphate (ATP) via selective coordination assembly leading to two-component metallo-hydrogel formation has been realized. With intensive fluorescent study and density functional theory calculations, it may be inferred, besides the selective metal-ligand interaction between Zn center and phosphate groups, the intramolecular π-stacking between the planar nucleobases of ATP and the metal-hybrid aromatic ring of pincer complex strongly affected the geometry of the coordinated adducts and possible molecular self-assembly process, which constitute a completely new sensing strategy in comparison with the conventional approaches. Furthermore, in light of extreme sensitivity of pincer zinc complexes toward ATP at micromolar scale (1.85 μM) and remarkable fluorescent enhancement (ca. 44-fold) upon ATP addition, the feasibility of the low cytotoxicity pincer zinc complexes in monitoring ATP in HeLa cells has been fulfilled with confocal fluorescence microscopy. PMID:27420773

  4. Interaction of Beta-Hydroxy-Beta-Methylbutyrate Free Acid and Adenosine Triphosphate on Muscle Mass, Strength, and Power in Resistance Trained Individuals.

    Science.gov (United States)

    Lowery, Ryan P; Joy, Jordan M; Rathmacher, John A; Baier, Shawn M; Fuller, John C; Shelley, Mack C; Jäger, Ralf; Purpura, Martin; Wilson, Stephanie M C; Wilson, Jacob M

    2016-07-01

    Lowery, RP, Joy, JM, Rathmacher, JA, Baier, SM, Fuller, JC Jr, Shelley, MC II, Jäger, R, Purpura, M, Wilson, SMC, and Wilson, JM. Interaction of beta-hydroxy-beta-methylbutyrate free acid and adenosine triphosphate on muscle mass, strength, and power in resistance trained individuals. J Strength Cond Res 30(7): 1843-1854, 2016-Adenosine-5'-triphosphate (ATP) supplementation helps maintain performance under high fatiguing contractions and with greater fatigue recovery demands also increase. Current evidence suggests that the free acid form of β-hydroxy-β-methylbutyrate (HMB-FA) acts by speeding regenerative capacity of skeletal muscle after high-intensity or prolonged exercise. Therefore, we investigated the effects of 12 weeks of HMB-FA (3 g) and ATP (400 mg) administration on lean body mass (LBM), strength, and power in trained individuals. A 3-phase double-blind, placebo-, and diet-controlled study was conducted. Phases consisted of an 8-week periodized resistance training program (phase 1), followed by a 2-week overreaching cycle (phase 2), and a 2-week taper (phase 3). Lean body mass was increased by a combination of HMB-FA/ATP by 12.7% (p power were increased in the HMB-FA/ATP-supplemented group compared with the placebo-supplemented group, and the 12-week increases were 21.5 and 23.7%, respectively. During the overreaching cycle, strength and power declined in the placebo group (4.3-5.7%), whereas supplementation with HMB-FA/ATP resulted in continued strength gains (1.3%). In conclusion, HMB-FA and ATP in combination with resistance exercise training enhanced LBM, power, and strength. In addition, HMB-FA plus ATP blunted the typical response to overreaching, resulting in a further increase in strength during that period. It seems that the combination of HMB-FA/ATP could benefit those who continuously train at high levels such as elite athletes or military personnel.

  5. Simple, Fast and Selective Detection of Adenosine Triphosphate at Physiological pH Using Unmodified Gold Nanoparticles as Colorimetric Probes and Metal Ions as Cross-Linkers

    Directory of Open Access Journals (Sweden)

    Huan Pang

    2012-11-01

    Full Text Available We report a simple, fast and selective colorimetric assay of adenosine triphosphate (ATP using unmodified gold nanoparticles (AuNPs as probes and metal ions as cross-linkers. ATP can be assembled onto the surface of AuNPs through interaction between the electron-rich nitrogen atoms and the electron-deficient surface of AuNPs. Accordingly, Cu2+ ions induce a change in the color and UV/Vis absorbance of AuNPs by coordinating to the triphosphate groups and a ring nitrogen of ATP. A detection limit of 50 nM was achieved, which is comparable to or lower than that achievable by the currently used electrochemical, spectroscopic or chromatographic methods. The theoretical simplicity and high selectivity reported herein demonstrated that AuNPs-based colorimetric assay could be applied in a wide variety of fields by rationally designing the surface chemistry of AuNPs. In addition, our results indicate that ATP-modified AuNPs are less stable in Cu2+, Cd2+ or Zn2+-containing solutions due to the formation of the corresponding dimeric metal-ATP complexes.

  6. Fluorescence detection of adenosine-5'-triphosphate and alkaline phosphatase based on the generation of CdS quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Siyu; Wang, Xinyan; Pang, Shu; Na, Weidan; Yan, Xu; Su, Xingguang, E-mail: suxg@jlu.edu.cn

    2014-05-01

    Highlights: • Cd²⁺ reacts with S²⁻ to generate fluorescent CdS QDs with ATP. • ATP can be hydrolyzed by the enzymatic dephosphorylation of ALP. • Fluorescent CdS QDs could not be generated in the presence of ALP. • The analysis system was successfully applied to assay ATP and ALP. Abstract: We have developed an analytical method to detect adenosine-5'-triphosphate (ATP) and alkaline phosphatase (ALP) based on the generation of CdS quantum dots (QDs). We demonstrated that Cd²⁺ cation reacts with S²⁻anion to generate fluorescent CdS QDs in the presence of some certain amount of ATP. With increase in the ATP concentration, the fluorescence intensity of CdS QDs was also enhanced. ATP can be converted into adenosine by the dephosphorylation of ALP, so that the generation of CdS QDs would be inhibited in the presence of ALP. Therefore, this novel analysis system could be applied to assay ATP and ALP based on the growth of fluorescent CdS QDs.

  7. Reduced rate of adenosine triphosphate synthesis by in vivo 31P nuclear magnetic resonance spectroscopy and downregulation of PGC-1beta in distal skeletal muscle following burn.

    Science.gov (United States)

    Tzika, A Aria; Mintzopoulos, Dionyssios; Padfield, Katie; Wilhelmy, Julie; Mindrinos, Michael N; Yu, Hongue; Cao, Haihui; Zhang, Qunhao; Astrakas, Loukas G; Zhang, Jiangwen; Yu, Yong-Ming; Rahme, Laurence G; Tompkins, Ronald G

    2008-02-01

    Using a mouse model of burn trauma, we tested the hypothesis that severe burn trauma corresponding to 30% of total body surface area (TBSA) causes reduction in adenosine triphosphate (ATP) synthesis in distal skeletal muscle. We employed in vivo 31P nuclear magnetic resonance (NMR) in intact mice to assess the rate of ATP synthesis, and characterized the concomitant gene expression patterns in skeletal muscle in burned (30% TBSA) versus control mice. Our NMR results showed a significantly reduced rate of ATP synthesis and were complemented by genomic results showing downregulation of the ATP synthase mitochondrial F1 F0 complex and PGC-1beta gene expression. Our findings suggest that inflammation and muscle atrophy in burns are due to a reduced ATP synthesis rate that may be regulated upstream by PGC-1beta. These findings implicate mitochondrial dysfunction in distal skeletal muscle following burn injury. That PGC-1beta is a highly inducible factor in most tissues and responds to common calcium and cyclic adenosine monophosphate (cAMP) signaling pathways strongly suggests that it may be possible to develop drugs that can induce PGC-1beta.

  8. Clinical Observation on Adenosine Triphosphate Treatment of Paroxysmal Supraventricular Tachycardia%三磷酸腺苷治疗阵发性室上心动过速的临床观察

    Institute of Scientific and Technical Information of China (English)

    王宝金

    2014-01-01

    目的:探讨三磷酸腺苷对于治疗阵发性室上心动过速的临床效果。方法将我院接受治疗的40例患有阵发性室上心动过速的患者通过肘静脉注射三磷酸腺苷药物进行治疗,观察疗效。结果通过一段时间治疗观察发现,三磷酸腺苷对患有阵发性室上心动过速有很好的治疗效果,第一次转复成功达到92.5%。第二次转复成功,达到66.7%。结论临床研究表明,三磷酸腺苷对于PSVT有较强的治疗作用。%Objective To explore the clinical efficacy of the treatment of Paroxysmal Supraventricular Tachycardi awith Adenosine Triphosphate. Method The patients were treated in our hospital on 40 patients suffering from Paroxysmal Supraventricular Tachycardia treated by intravenous Adenosine Triphosphate elbow drugs, observing the effective.Results Treatment period of observation by finding, Adenosine Triphosphate on the body with Paroxysmal Supraventricular Tachycardia have a good therapeutic effect for the first time a successful cardioversion,it has reached 92.5%.e second cardioversion success, it has reached 66.7%.Conclusion Clinical studies have shown that adenosine triphosphate for PSVT has a strong therapeutic effect.

  9. Adenosine triphosphate-sensitive potassium channel opener protects PC12 cells against hypoxia-induced apoptosis through PI3K/Akt and Bcl-2 signaling pathways

    Institute of Scientific and Technical Information of China (English)

    Hong Zhang; Chunhong Jia; Danyang Zhao; Yang Lu; Runling Wang; Jia Li

    2010-01-01

    Although previous studies have shown the neuroprotective effects of the adenosine triphosphate (ATP)-sensitive potassium (KATP) channel opener against ischemic neuronal damage, little is known about the mechanisms involved. Phosphatidylinositol-3 kinase (PI3K)/v-akt murine thy-moma viral oncogene homolog (Akt) and Bcl-2 are thought to be important factors that mediate neuroprotection. The present study investigated the effects of KATP openers on hypoxia-induced PC12 cell apoptosis, as well as mRNA and protein expression of Akt and Bcl-2. Results demon-strated that pretreatment of PC12 cells with pinacidil, a KATP opener, resulted in decreased PC12 cell apoptosis following hypoxia, as detected by Annexin-V fluorescein isothiocyanate/ propidium iodide double staining flow cytometry. In addition, mRNA and protein expression of phosphorylated Akt (p-Akt) and Bcl-2 increased, as detected by immunofluorescence, Western blot analysis, and reverse-transcription polymerase chain reaction. The protective effect of this preconditioning was attenuated by glipizide, a selective KATP blocker. These results demonstrate for the first time that the protective mechanisms of KATP openers on PC12 cell apoptosis following hypoxia could result from activation of the PI3K/Akt signaling pathway, which further activates expression of the downstream Bcl-2 gene.

  10. Flow cytometry and adenosine tri-phosphate analysis: alternative possibilities to evaluate major bacteriological changes in drinking water treatment and distribution systems.

    Science.gov (United States)

    Vital, Marius; Dignum, Marco; Magic-Knezev, Aleksandra; Ross, Petra; Rietveld, Luuk; Hammes, Frederik

    2012-10-01

    An ever-growing need exists for rapid, quantitative and meaningful methods to quantify and characterize the effect of different treatment steps on the microbiological processes and events that occur during drinking water treatment and distribution. Here we compared cultivation-independent flow cytometry (FCM) and adenosine tri-phosphate (ATP) analysis with conventional cultivation-based microbiological methods, on water samples from two full-scale treatment and distribution systems. The two systems consist of nearly identical treatment trains, but their raw water quality and pre-treatment differed significantly. All of the drinking water treatment processes affected the microbiological content of the water considerably, but once treated, the finished water remained remarkably stable throughout the distribution system. Both the FCM and ATP data were able to describe the microbiology of the systems accurately, providing meaningful process data when combined with other parameters such as dissolved organic carbon analysis. Importantly, the results highlighted a complimentary value of the two independent methods: while similar trends were mostly observed, variations in ATP-per-cell values between water samples were adequately explained by differences in the FCM fingerprints of the samples. This work demonstrates the value of alternative microbial methods for process/system control, optimization and routine monitoring of the general microbial quality of water during treatment and distribution. PMID:22763289

  11. Use of a Sampling Area-Adjusted Adenosine Triphosphate Bioluminescence Assay Based on Digital Image Quantification to Assess the Cleanliness of Hospital Surfaces

    Science.gov (United States)

    Ho, Yu-Huai; Wang, Lih-Shinn; Jiang, Hui-Li; Chang, Chih-Hui; Hsieh, Chia-Jung; Chang, Dan-Chi; Tu, Hsin-Yu; Chiu, Tan-Yun; Chao, Huei-Jen; Tseng, Chun-Chieh

    2016-01-01

    Contaminated surfaces play an important role in the transmission of pathogens. We sought to establish a criterion that could indicate “cleanliness” using a sampling area–adjusted adenosine triphosphate (ATP) assay. In the first phase of the study, target surfaces were selected for swab sampling before and after daily cleaning; then, an aerobic colony count (ACC) plate assay of bacteria and antibiotic-resistant bacteria was conducted. ATP swabs were also tested, and the ATP readings were reported as relative light units (RLUs). The results of the ACC and ATP assays were adjusted according to the sampling area. During the second phase of the study, a new cleaning process employing sodium dichloroisocyanurate (NaDCC) was implemented for comparison. Using the criterion of 2.5 colony-forming units (CFU)/cm2, 45% of the sampled sites were successfully cleaned during phase one of the study. During phase two, the pass rates of the surface samples (64%) were significantly improved, except under stringent (5 RLU/cm2) and lax (500 RLU) ATP criteria. Using receiver-operating characteristic curve analysis, the best cut-off point for an area-adjusted ATP level was 7.34 RLU/cm2, which corresponded to culture-assay levels of <2.5 CFU/cm2. An area adjustment of the ATP assay improved the degree of correlation with the ACC-assay results from weak to moderate. PMID:27294944

  12. Proline modulates the effect of bisphosphonate on calcium levels and adenosine triphosphate production in cell lines derived from bovine Echinococcus granulosus protoscoleces.

    Science.gov (United States)

    Fuchs, A G; Echeverría, C I; Pérez Rojo, F G; Prieto González, E A; Roldán, E J A

    2014-12-01

    Bisphosphonates have been proposed as pharmacological agents against parasite and cancer cell growth. The effect of these compounds on helminthic cell viability and acellular compartment morphology, however, has not yet been studied. The effects of different types of bisphosphonates, namely etidronate (EHDP), pamidronate (APD), alendronate (ABP), ibandronate (IB) and olpadronate (OPD), and their interaction with amiloride, 1,25-dihydroxycholecalciferol (D3) and proline were evaluated on a cell line derived from bovine Echinococcus granulousus protoscoleces (EGPE) that forms cystic colonies in agarose. The EGPE cell line allowed testing the effect of bisphosphonates alone and in association with other compounds that could modulate calcium apposition/deposition, and were useful in measuring the impact of these compounds on cell growth, cystic colony formation and calcium storage. Decreased cell growth and cystic colony formation were found with EHDP, IB and OPD, and increased calcium storage with EHDP only. Calcium storage in EGPE cells appeared to be sensitive to the effect of amiloride, D3 and proline. Proline decreased calcium storage and increased colony formation. Changes in calcium storage may be associated with degenerative changes of the cysts, as shown in the in vitro colony model and linked to an adenosine triphosphate (ATP) decrease. In conclusion, bisphosphonates could be suitable tempering drugs to treat cestode infections.

  13. Use of a Sampling Area-Adjusted Adenosine Triphosphate Bioluminescence Assay Based on Digital Image Quantification to Assess the Cleanliness of Hospital Surfaces.

    Science.gov (United States)

    Ho, Yu-Huai; Wang, Lih-Shinn; Jiang, Hui-Li; Chang, Chih-Hui; Hsieh, Chia-Jung; Chang, Dan-Chi; Tu, Hsin-Yu; Chiu, Tan-Yun; Chao, Huei-Jen; Tseng, Chun-Chieh

    2016-01-01

    Contaminated surfaces play an important role in the transmission of pathogens. We sought to establish a criterion that could indicate "cleanliness" using a sampling area-adjusted adenosine triphosphate (ATP) assay. In the first phase of the study, target surfaces were selected for swab sampling before and after daily cleaning; then, an aerobic colony count (ACC) plate assay of bacteria and antibiotic-resistant bacteria was conducted. ATP swabs were also tested, and the ATP readings were reported as relative light units (RLUs). The results of the ACC and ATP assays were adjusted according to the sampling area. During the second phase of the study, a new cleaning process employing sodium dichloroisocyanurate (NaDCC) was implemented for comparison. Using the criterion of 2.5 colony-forming units (CFU)/cm², 45% of the sampled sites were successfully cleaned during phase one of the study. During phase two, the pass rates of the surface samples (64%) were significantly improved, except under stringent (5 RLU/cm²) and lax (500 RLU) ATP criteria. Using receiver-operating characteristic curve analysis, the best cut-off point for an area-adjusted ATP level was 7.34 RLU/cm², which corresponded to culture-assay levels of <2.5 CFU/cm². An area adjustment of the ATP assay improved the degree of correlation with the ACC-assay results from weak to moderate. PMID:27294944

  14. In Vitro Adenosine Triphosphate-Based Chemotherapy Response Assay as a Predictor of Clinical Response to Fluorouracil-Based Adjuvant Chemotherapy in Stage II Colorectal Cancer

    Science.gov (United States)

    Kwon, Hye Youn; Kim, Im-kyung; Kang, Jeonghyun; Sohn, Seung-Kook; Lee, Kang Young

    2016-01-01

    Purpose We evaluated the usefulness of the in vitro adenosine triphosphate-based chemotherapy response assay (ATP-CRA) for prediction of clinical response to fluorouracil-based adjuvant chemotherapy in stage II colorectal cancer. Materials and Methods Tumor specimens of 86 patients with pathologically confirmed stage II colorectal adenocarcinoma were tested for chemosensitivity to fluorouracil. Chemosensitivity was determined by cell death rate (CDR) of drug-exposed cells, calculated by comparing the intracellular ATP level with that of untreated controls. Results Among the 86 enrolled patients who underwent radical surgery followed by fluorouracil-based adjuvant chemotherapy, recurrence was found in 11 patients (12.7%). The CDR ≥ 20% group was associated with better disease-free survival than the CDR < 20% group (89.4% vs. 70.1%, p=0.027). Multivariate analysis showed that CDR < 20% and T4 stage were poor prognostic factors for disease-free survival after fluorouracil-based adjuvant chemotherapy. Conclusion In stage II colorectal cancer, the in vitro ATP-CRA may be useful in identifying patients likely to benefit from fluorouracil-based adjuvant chemotherapy. PMID:26511802

  15. Comparison of immunomagnetic separation/adenosine triphosphate rapid method to traditional culture-based method for E. coli and enterococci enumeration in wastewater.

    Science.gov (United States)

    Bushon, Rebecca N; Likirdopulos, Christina A; Brady, Amie M G

    2009-11-01

    Untreated wastewater samples from California, North Carolina, and Ohio were analyzed by the immunomagnetic separation/adenosine triphosphate (IMS/ATP) method and the traditional culture-based method for E. coli and enterococci concentrations. The IMS/ATP method concentrates target bacteria by immunomagnetic separation and then quantifies captured bacteria by measuring bioluminescence induced by release of ATP from the bacterial cells. Results from this method are available within 1h from the start of sample processing. Significant linear correlations were found between the IMS/ATP results and results from traditional culture-based methods for E. coli and enterococci enumeration for one location in California, two locations in North Carolina, and one location in Ohio (r values ranged from 0.87 to 0.97). No significant linear relation was found for a second location in California that treats a complex mixture of residential and industrial wastewater. With the exception of one location, IMS/ATP showed promise as a rapid method for the quantification of faecal-indicator organisms in wastewater.

  16. Comparison of immunomagnetic separation/adenosine triphosphate rapid method to traditional culture-based method for E. coli and enterococci enumeration in wastewater

    Science.gov (United States)

    Bushon, R.N.; Likirdopulos, C.A.; Brady, A.M.G.

    2009-01-01

    Untreated wastewater samples from California, North Carolina, and Ohio were analyzed by the immunomagnetic separation/adenosine triphosphate (IMS/ATP) method and the traditional culture-based method for E. coli and enterococci concentrations. The IMS/ATP method concentrates target bacteria by immunomagnetic separation and then quantifies captured bacteria by measuring bioluminescence induced by release of ATP from the bacterial cells. Results from this method are available within 1 h from the start of sample processing. Significant linear correlations were found between the IMS/ATP results and results from traditional culture-based methods for E. coli and enterococci enumeration for one location in California, two locations in North Carolina, and one location in Ohio (r??values ranged from 0.87 to 0.97). No significant linear relation was found for a second location in California that treats a complex mixture of residential and industrial wastewater. With the exception of one location, IMS/ATP showed promise as a rapid method for the quantification of faecal-indicator organisms in wastewater.

  17. An ultrasensitive quantum dots fluorescent polarization immunoassay based on the antibody modified Au nanoparticles amplifying for the detection of adenosine triphosphate.

    Science.gov (United States)

    He, Yanlong; Tian, Jianniao; Hu, Kun; Zhang, Juanni; Chen, Sheng; Jiang, Yixuan; Zhao, Yanchun; Zhao, Shulin

    2013-11-13

    In this work, an ultrasensitive fluorescent polarization immunoassay (FPIA) method based on the quantum dot/aptamer/antibody/gold nanoparticles ensemble has been developed for the detection of adenosine triphosphate (ATP). DNA hybridization is formed when ATP is present in the PBS solution containing the DNA-conjugated quantum dots (QDs) and antibody-AuNPs. The substantial sensitivity improvement of the antibody-AuNPs-enhanced method is mainly attributed to the slower rotation of fluorescent unit when QDs-labeled oligonucleotides hybridize with antibody modified the gold nanoparticle. As a result, the fluorescent polarization (FP) values of the system increase significantly. Under the optimal conditions, a linear response with ATP concentration is ranged from 8×10(-12) M to 2.40×10(-4) M. The detection limit reached as low as 1.8 pM. The developed work provides a sensitive and selective immunoassay protocol for ATP detection, which could be applied in more bioanalytical systems. PMID:24176506

  18. An ultrasensitive quantum dots fluorescent polarization immunoassay based on the antibody modified Au nanoparticles amplifying for the detection of adenosine triphosphate

    International Nuclear Information System (INIS)

    Graphical abstract: A new fluorescent polarization immunoassay (FPIA) method for ATP was structured. The fluorescence polarization method has ultrahigh sensitivity and good selectivity. The method could be applied for the ATP detection in bioanalysis. -- Highlights: •A new fluorescent polarization immunoassay (FPIA) method for ATP was structured. •The fluorescence polarization method has ultrahigh sensitivity and good selectivity. •The method could be applied for the ATP detection in bioanalysis. -- Abstract: In this work, an ultrasensitive fluorescent polarization immunoassay (FPIA) method based on the quantum dot/aptamer/antibody/gold nanoparticles ensemble has been developed for the detection of adenosine triphosphate (ATP). DNA hybridization is formed when ATP is present in the PBS solution containing the DNA-conjugated quantum dots (QDs) and antibody-AuNPs. The substantial sensitivity improvement of the antibody-AuNPs-enhanced method is mainly attributed to the slower rotation of fluorescent unit when QDs-labeled oligonucleotides hybridize with antibody modified the gold nanoparticle. As a result, the fluorescent polarization (FP) values of the system increase significantly. Under the optimal conditions, a linear response with ATP concentration is ranged from 8 × 10−12 M to 2.40 × 10−4 M. The detection limit reached as low as 1.8 pM. The developed work provides a sensitive and selective immunoassay protocol for ATP detection, which could be applied in more bioanalytical systems

  19. An ultrasensitive quantum dots fluorescent polarization immunoassay based on the antibody modified Au nanoparticles amplifying for the detection of adenosine triphosphate

    Energy Technology Data Exchange (ETDEWEB)

    He, Yanlong; Tian, Jianniao, E-mail: birdtjn@sina.com; Hu, Kun; Zhang, Juanni; Chen, Sheng; Jiang, Yixuan; Zhao, Yanchun, E-mail: yanchunzh@sina.com; Zhao, Shulin

    2013-11-13

    Graphical abstract: A new fluorescent polarization immunoassay (FPIA) method for ATP was structured. The fluorescence polarization method has ultrahigh sensitivity and good selectivity. The method could be applied for the ATP detection in bioanalysis. -- Highlights: •A new fluorescent polarization immunoassay (FPIA) method for ATP was structured. •The fluorescence polarization method has ultrahigh sensitivity and good selectivity. •The method could be applied for the ATP detection in bioanalysis. -- Abstract: In this work, an ultrasensitive fluorescent polarization immunoassay (FPIA) method based on the quantum dot/aptamer/antibody/gold nanoparticles ensemble has been developed for the detection of adenosine triphosphate (ATP). DNA hybridization is formed when ATP is present in the PBS solution containing the DNA-conjugated quantum dots (QDs) and antibody-AuNPs. The substantial sensitivity improvement of the antibody-AuNPs-enhanced method is mainly attributed to the slower rotation of fluorescent unit when QDs-labeled oligonucleotides hybridize with antibody modified the gold nanoparticle. As a result, the fluorescent polarization (FP) values of the system increase significantly. Under the optimal conditions, a linear response with ATP concentration is ranged from 8 × 10{sup −12} M to 2.40 × 10{sup −4} M. The detection limit reached as low as 1.8 pM. The developed work provides a sensitive and selective immunoassay protocol for ATP detection, which could be applied in more bioanalytical systems.

  20. Safety and feasibility of thallium-201 myocardial SPECT with intravenous infusion of disodium adenosine triphosphate (ATP) in the diagnosis of coronary artery disease

    International Nuclear Information System (INIS)

    ATP (adenosine triphosphate) is a potent coronary vasodilator with a rapid onset of action and a very short half-life. Myocardial perfusion scintigraphy with intravenous ATP has not yet bee sufficiently proven in the diagnosis, follow-up, and risk stratification of coronary artery disease. The purpose of this study was to evaluate the safety, feasibility and diagnostic accuracy of pharmacologic stress thallium-102 myocardial SPECT using an intravenous ATP infusion in patients with suspected coronary artery disease. Thallium-201 myocardial SPECT in 319 patients with suspected coronary artery disease were performed after the infusion of ATP (0.08 mg/min for 6 min). The adverse effects were carefully monitored. Coronary angiography was also performed within 3 weeks. Although 76.5% of he patients had some adverse effects, they were transient, mild, and well tolerated. In all patients, the ATP infusion protocol was completed and only 2 patients required aminophylline. The adverse effects were dyspnea in 63%, headache in 31%, flushing in 21%, chest pain in 14% and abdominal discomfort in 5% of the patients. The sensitivity and specificity were 80% and 90% respectively. Thallium-201 myocardial SPECT after 6 min-infusion of ATP at a rate of 0.08 mg/kg/min is safe and has a diagnostic value in detecting coronary artery disease

  1. Adenosine Triphosphate (ATP) Inhibits Voltage-Sensitive Potassium Currents in Isolated Hensen’s Cells and Nifedipine Protects Against Noise-Induced Hearing Loss in Guinea Pigs

    Science.gov (United States)

    Ye, Rui; Liu, Jun; Jia, Zhiying; Wang, Hongyang; Wang, YongAn; Sun, Wei; Wu, Xuan; Zhao, Zhifei; Niu, Baolong; Li, Xingqi; Dai, Guanghai; Li, Jianxiong

    2016-01-01

    Background There is increasing evidence that adenosine triphosphate (ATP), a well-known neurotransmitter and neuromodulator in the central nervous system, plays an important role as an extracellular chemical messenger in the cochlea. Material/Methods Using a whole-cell recording technique, we studied the effects of ATP on isolated Hensen’s cells, which are supporting cells in the cochlea, to determine if they are involved in the transduction of ions with hair cells. Results ATP (0.1–10 μM) reduced the potassium current (IK+) in the majority of the recorded Hensen’s cells (21 out of 25 cells). An inward current was also induced by high concentrations of ATP (100 μM to 10 mM), which was reversibly blocked by 100 μM suramin (a purinergic antagonist) and blocked by nifedipine (an L-type calcium channel blocker). After the cochleas were perfused with artificial perilymph solutions containing nifedipine and exposed to noise, the amplitude increase in the compound action potential (CAP) threshold and the reduction in cochlear microphonics was lower than when they were exposed to noise alone. Conclusions Our results suggest that ATP can block IK+ channels at a low concentration and induce an inward Ca2+ current at high concentrations, which is reversed by purinergic receptors. Nifedipine may have a partially protective effect on noise-induced hearing loss (NIHL). PMID:27292522

  2. Inactivation efficiency of Escherichia coli and autochthonous bacteria during ozonation of municipal wastewater effluents quantified with flow cytometry and adenosine tri-phosphate analyses.

    Science.gov (United States)

    Lee, Yunho; Imminger, Stefanie; Czekalski, Nadine; von Gunten, Urs; Hammes, Frederik

    2016-09-15

    Inactivation kinetics of autochthonous bacteria during ozonation of wastewater effluents were investigated using cultivation-independent flow cytometry (FCM) with total cell count (TCC) and intact cell count (ICC) and intracellular adenosine triphosphate (ATP) analysis. The principles of the methods including ozone inactivation kinetics were demonstrated with laboratory-cultured Escherichia coli spiked into filtered and sterilized wastewater effluent. Both intracellular ATP and ICC decreased with increasing ozone doses, with ICC being the more conservative parameter. The log-inactivation levels (-log(N/N0) of E. coli reached the method detection limits for FCM (∼3) and ATP (∼1.7) at specific ozone doses of ≥0.5 gO3/gDOC. During ozonation of four real wastewater effluents, the log-inactivation of autochthonous bacteria with FCM ICC was 0.3-1.0 for 0.25 gO3/gDOC and increased to 1.1-2.1 for 0.5 gO3/gDOC, but remained at a similar level of 1.5-2.8 for a further increase of the specific ozone doses to 1.0 and 1.5 gO3/gDOC. The FCM data also showed that autochthonous bacteria were composed of communities with high and low ozone reactivity. The inactivation levels measured with intracellular ATP were reasonably correlated to ICC (r(2) = 0.8). Overall, FCM and ATP measurements were demonstrated to be useful tools to monitor the inactivation of autochthonous bacteria during ozonation of municipal wastewater effluents. PMID:27322566

  3. Using an Adenosine Triphosphate Bioluminescent Assay to Determine Effective Antibiotic Combinations against Carbapenem-Resistant Gram Negative Bacteria within 24 Hours.

    Directory of Open Access Journals (Sweden)

    Yiying Cai

    Full Text Available Current in vitro combination testing methods involve enumeration by bacterial plating, which is labor-intensive and time-consuming. Measurement of bioluminescence, released when bacterial adenosine triphosphate binds to firefly luciferin-luciferase, has been proposed as a surrogate for bacterial counts. We developed an ATP bioluminescent combination testing assay with a rapid turnaround time of 24h to determine effective antibiotic combinations.100 strains of carbapenem-resistant (CR GNB [30 Acinetobacter baumannii (AB, 30 Pseudomonas aeruginosa (PA and 40 Klebsiella pneumoniae (KP] were used. Bacterial suspensions (105 CFU/ml were added to 96-well plates containing clinically achievable concentrations of multiple single and two-antibiotic combinations. At 24h, the luminescence intensity of each well was measured. Receiver operator characteristic curves were plotted to determine optimal luminescence threshold (TRLU to discriminate between inhibitory/non-inhibitory combinations when compared to viable plating. The unweighted accuracy (UA [(sensitivity + specificity/2] of TRLU values was determined. External validation was further done using 50 additional CR-GNB.Predictive accuracies of TRLU were high for when all antibiotic combinations and species were collectively analyzed (TRLU = 0.81, UA = 89%. When individual thresholds for each species were determined, UA remained high. Predictive accuracy was highest for KP (TRLU = 0.81, UA = 91%, and lowest for AB (TRLU = 0.83, UA = 87%. Upon external validation, high overall accuracy (91% was observed. The assay distinguished inhibitory/non-inhibitory combinations with UA of 80%, 94% and 93% for AB, PA and KP respectively.We developed an assay that is robust at identifying useful combinations with a rapid turn-around time of 24h, and may be employed to guide the timely selection of effective antibiotic combinations.

  4. Construction of deletion mutants in the phosphotransferase transport system and adenosine triphosphate-binding cassette transporters in Listeria monocytogenes and analysis of their growth under different stress conditions

    Directory of Open Access Journals (Sweden)

    Marina Ceruso

    2013-10-01

    Full Text Available Functional genomics approaches enable us to investigate the biochemical, cellular, and physiological properties of each gene product and are nowadays applied to enhance food safety by understanding microbial stress responses in food and host-pathogen interactions. Listeria monocytogenes is a food-borne pathogen that causes listeriosis and is difficult to eliminate this pathogen since it can survive under multiple stress conditions such as low pH and low temperature. Detailed studies are needed to determine its mode of action and to understand the mechanisms that protect the pathogen when it is subjected to stress. In this study, deletion mutants of phosphotransferase transport system genes (PTS and adenosine triphosphate(ATP-binding cassette transporters (ABC of Listeria monocytogenes F2365 were created using molecular techniques. These mutants and the wild-type were tested under different stress conditions, such as in solutions with different NaCl concentration, pH value and for nisin resistance. Results demonstrate that the behaviour of these deletion mutants is different from the wild type. In particular, deleted genes may be involved in L. monocytogenes resistance to nisin and to acid and salt concentrations. Functional genomics research on L. monocytogenes allows a better understanding of the genes related to stress responses and this knowledge may help in intervention strategies to control this food-borne pathogen. Furthermore, specific gene markers can be used to identify and subtype L. monocytogenes. Thus, future development of this study will focus on additional functional analyses of important stress response-related genes, as well as on methods for rapid and sensitive detection of L. monocytogenes such as using DNA microarrays.

  5. Effects of repetitive transcranial magnetic stimulation on adenosine triphosphate content and microtubule associated protein-2 expression after cerebral ischemia-reperfusion injury in rat brain

    Institute of Scientific and Technical Information of China (English)

    FENG Hong-lin; YAN Li; CUI Li-ying

    2008-01-01

    Background Repetitive transcranial magnetic stimulation (rTMS) research has mainly been focused on the therapeutic effect of psychiatric disorders and Parkinson's disease. A few studies have shown that rTMS might protect against delayed neuronal death induced by transient ischemia, enhance long-term potentiation in ischemic conditions and affect regional brain blood flow and metabolism. The aim of this study was to determine the effects of repetitive transcranial magnetic stimulation (rTMS) on adenosine triphosphate (ATP) content and microtubule associated protein-2 (MAP-2) expression in rat brain after middle cerebral artery occlusion (MCAO)/reperfusion.Methods To study the effects of different timecourses of rTMS on ATP content and MAP-2 expression, 90 rats were randomly divided into three groups (30 rats in each group). To study the effects of multiple rTMS parameters on ATP content and MAP-2 expression, the rats in each group were further divided into six subgroups (five rats each). The rats were sacrificr, 24-hour and 48-hour intervals after reperfusion, and the brain tissues were collected for the detection of ATP and MAP-2.Results rTMS could significantly increase ATP content and MAP-2 expression in the left brain following ischemic insult (P<0.01) and different rTMS parameters had different effects on the ATP level and the MAP-2 expression in the left striatum. A high-frequency rTMS played an important role in MAP-2 expression and ATP preservation.Conclusions This study revealed that rTMS induced significant increase of ATP content and MAP-2 expression in the injured area of the brain, suggesting that the regulation of both ATP and MAP-2 may be involved in the biological mechanism of the effect of rTMS on neural recovery. Therefore, rTMS may become a potential adjunctive therapy for ischemic cerebrovascular disease.

  6. Electrochemical oxidation of adenosine-5 Prime -triphosphate on a chitosan-graphene composite modified carbon ionic liquid electrode and its determination

    Energy Technology Data Exchange (ETDEWEB)

    Sun Wei, E-mail: swyy26@hotmail.com [College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou, 571158 (China); College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Liu Jun; Wang Xiuzhen; Li Tongtong; Li Guangjiu; Wu Jie [College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Zhang Liqi [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2012-10-01

    In this paper a new electrochemical method was proposed for the determination of adenosine-5 Prime -triphosphate (ATP) based on a chitosan (CTS) and graphene (GR) composite film modified carbon ionic liquid electrode (CTS-GR/CILE). CILE was fabricated by using ionic liquid 1-butyl-3-methylimidazolium dihydrogen phosphate ([BMIM]H{sub 2}PO{sub 4}) as the binder, which was further modified by GR and CTS composite. The modified electrode exhibited an excellent electrocatalytic activity toward the oxidation of ATP with the increase of the oxidation peak current and the decrease of the oxidation peak potential. The electrochemical parameters of ATP on CTS-GR/CILE were calculated with the electron transfer coefficient ({alpha}) as 0.329, the electron transfer number (n) as 2.15, the apparent heterogeneous electron transfer rate constant (ks) as 3.705 Multiplication-Sign 10{sup -5} s{sup -1} and the surface coverage ({Gamma}{sub T}) as 9.33 Multiplication-Sign 10{sup -10} mol cm{sup -2}. Under the optimal conditions the oxidation peak current was proportional to ATP concentration in the range from 1.0 Multiplication-Sign 10{sup -6} to 1.0 Multiplication-Sign 10{sup -3} M with the detection limit of 0.311 {mu}M (S/N = 3). The proposed electrode showed excellent reproducibility, stability, anti-interference ability and further successfully applied to the ATP injection sample detection. - Highlights: Black-Right-Pointing-Pointer Ionic liquid [BMIM]H{sub 2}PO{sub 4} based carbon ionic liquid electrode (CILE) was prepared. Black-Right-Pointing-Pointer Graphene modified CILE was fabricated for the sensitive electrochemical detection of ATP. Black-Right-Pointing-Pointer Good electrocatalytic ability to the ATP oxidation was achieved. Black-Right-Pointing-Pointer Detection of 5 Prime -ATP in commercial injection samples with satisfactory results.

  7. 运动与ATP-敏感型钾离子通道%Exercise and adenosine triphosphate-sensitive potassium channel

    Institute of Scientific and Technical Information of China (English)

    张如江; 宋永晶

    2014-01-01

    背景:在运动生理状态下,KATP 在调节冠状动脉张力、运动诱导心肌保护效应和延缓骨骼肌疲劳等多个方面具有重要作用。目的:对KATP在运动中的作用进行了综述和探讨,以期为深入了解运动调节机体代谢提供理论参考。方法:检索1991年1月至2014年6月 PubMed数据库及维普中文科技数据库文献。英文检索词为“KATP Channels;Adenosine Triphosphate;Sports;Myocardium;Ion Channels”,中文检索词为“KATP通道;三磷酸腺苷;运动;心肌;离子通道”。选择与KATP分子结构、生物学功能及调控相关,以及KATP与冠状动脉、心肌、骨骼肌疲劳及运动能力相关的文献42篇文献进行探讨。结果与结论:ATP敏感性钾离子通道可以偶联细胞内能量代谢和细胞膜兴奋性,在应对各种生理和病理应激时是保护心肌的效应器之一。长期的耐力训练则会增加骨骼肌和心肌KATP的表达,可能是心肌和骨骼肌对运动应激产生的一种适应性表现。KATP 可能参与冠状动脉血流量的调节。在运动诱导的减轻心肌缺血再灌注损伤的保护效应中,心肌KATP具有重要作用。当骨骼肌疲劳发生时,KATP的激活有利于防止ATP的过度消耗而造成肌纤维损伤和细胞死亡,有利于疲劳的快速恢复。关于KATP与运动能力的关系仍需进一步的研究。%BACKGROUND:In the condition of exercise physiology, adenosine triphosphate-sensitive potassium (KATP) channel plays an important role in many aspects, such as regulation of coronary artery tension, exercise-induced myocardial protection effect and delay of skeletal muscle fatigue. OBJECTIVE:To review and investigate the role of KATP in exercise in order to provide theoretical reference for understanding mechanism underlying exercise regulation of body’s metabolism. METHODS: A computer-based online search of PubMed and VIP databases was performed for articles

  8. Clinical significance of high-density lipoproteins and the development of atherosclerosis: focus on the role of the adenosine triphosphate-binding cassette protein A1 transporter.

    Science.gov (United States)

    Brewer, H Bryan; Santamarina-Fojo, Silvia

    2003-08-21

    Low levels of high-density lipoprotein (HDL) cholesterol constitute a risk factor for coronary artery disease, and there is evidence that increasing HDL cholesterol levels reduces cardiovascular risk. The phenotype of low HDL cholesterol with or without elevated triglycerides is at least as common in patients hospitalized for cardiovascular disease as is hypercholesterolemia, and it is characteristic of diabetes and the metabolic syndrome, conditions associated with increased cardiovascular risk. Recent studies have elucidated mechanisms by which HDL acts to reduce cardiovascular risk, bolstering the rationale for targeting of HDL in lipid-modifying therapy. In particular, HDL (1) carries excess cholesterol from peripheral cells to the liver for removal in the process termed reverse cholesterol transport, (2) reduces oxidative modification of low-density lipoproteins (LDL), and (3) inhibits cytokine-induced expression of cellular adhesion molecules on endothelial cells. Studies of the newly described adenosine triphosphate-binding cassette protein A1 (ABCA1) transporter have established a crucial role for this transporter in modulating the levels of plasma HDL and intracellular cholesterol in the liver as well as in peripheral cells. Elevated levels of intracellular cholesterol stimulate the liver X receptor pathway, enhancing the expression of ABCA1, which increases intracellular trafficking of excess cholesterol to the cell surface for interaction with lipid-poor apolipoprotein A-I to form nascent HDL. Nascent HDL facilitates the removal of additional excess cellular cholesterol, which is esterified by lecithin-cholesterol acyltransferase with conversion of the nascent HDL to mature spherical HDL. Overexpression of ABCA1 in mice on a regular chow or Western diet results in a marked increase in plasma HDL, increased LDL, and increased transport of cholesterol to the liver. On a high cholesterol/cholate diet, transgenic mice overexpressing ABCA1 have increased HDL

  9. Adenosine 5′-triphosphate (ATP supplements are not orally bioavailable: a randomized, placebo-controlled cross-over trial in healthy humans

    Directory of Open Access Journals (Sweden)

    Arts Ilja CW

    2012-04-01

    Full Text Available Abstract Background Nutritional supplements designed to increase adenosine 5′-triphosphate (ATP concentrations are commonly used by athletes as ergogenic aids. ATP is the primary source of energy for the cells, and supplementation may enhance the ability to maintain high ATP turnover during high-intensity exercise. Oral ATP supplements have beneficial effects in some but not all studies examining physical performance. One of the remaining questions is whether orally administered ATP is bioavailable. We investigated whether acute supplementation with oral ATP administered as enteric-coated pellets led to increased concentrations of ATP or its metabolites in the circulation. Methods Eight healthy volunteers participated in a cross-over study. Participants were given in random order single doses of 5000 mg ATP or placebo. To prevent degradation of ATP in the acidic environment of the stomach, the supplement was administered via two types of pH-sensitive, enteric-coated pellets (targeted at release in the proximal or distal small intestine, or via a naso-duodenal tube. Blood ATP and metabolite concentrations were monitored by HPLC for 4.5 h (naso-duodenal tube or 7 h (pellets post-administration. Areas under the concentration vs. time curve were calculated and compared by paired-samples t-tests. Results ATP concentrations in blood did not increase after ATP supplementation via enteric-coated pellets or naso-duodenal tube. In contrast, concentrations of the final catabolic product of ATP, uric acid, were significantly increased compared to placebo by ~50% after administration via proximal-release pellets (P = 0.003 and naso-duodenal tube (P = 0.001, but not after administration via distal-release pellets. Conclusions A single dose of orally administered ATP is not bioavailable, and this may explain why several studies did not find ergogenic effects of oral ATP supplementation. On the other hand, increases in uric acid after release of

  10. Quantitative circumferential strain analysis using adenosine triphosphate-stress/rest 3-T tagged magnetic resonance to evaluate regional contractile dysfunction in ischemic heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Masashi, E-mail: m.nakamura1230@gmail.com [Department of Radiology, Ehime University Graduate School of Medicine, Shitsukawa, Toon-city, Ehime 791-0295 (Japan); Kido, Tomoyuki [Department of Radiology, Saiseikai Matsuyama Hospital, Ehime 791-0295 (Japan); Kido, Teruhito; Tanabe, Yuki; Matsuda, Takuya; Nishiyama, Yoshiko; Miyagawa, Masao; Mochizuki, Teruhito [Department of Radiology, Ehime University Graduate School of Medicine, Shitsukawa, Toon-city, Ehime 791-0295 (Japan)

    2015-08-15

    Highlights: • Infarcted segments could be differentiated from non-ischemic and ischemic segments with high sensitivity and specificity under at rest conditions. • The time-to-peak circumferential strain values in infarcted segments were more significantly delayed than those in non-ischemic and ischemic segments. • Both circumferential strain and circumferential systolic strain rate values under ATP-stress conditions were significantly lower in ischemic segments than in non-ischemic segments. • Subtracting stress and rest circumferential strain had a higher diagnostic capability for ischemia relative to only utilizing rest or ATP-stress circumferential strain values. • A circumferential strain analysis using tagged MR can quantitatively assess contractile dysfunction in ischemic and infarcted myocardium. - Abstract: Purpose: We evaluated whether a quantitative circumferential strain (CS) analysis using adenosine triphosphate (ATP)-stress/rest 3-T tagged magnetic resonance (MR) imaging can depict myocardial ischemia as contractile dysfunction during stress in patients with suspected coronary artery disease (CAD). We evaluated whether it can differentiate between non-ischemia, myocardial ischemia, and infarction. We assessed its diagnostic performance in comparison with ATP-stress myocardial perfusion MR and late gadolinium enhancement (LGE)-MR imaging. Methods: In 38 patients suspected of having CAD, myocardial segments were categorized as non-ischemic (n = 485), ischemic (n = 74), or infarcted (n = 49) from the results of perfusion MR and LGE-MR. The peak negative CS value, peak circumferential systolic strain rate (CSR), and time-to-peak CS were measured in 16 segments. Results: A cutoff value of −12.0% for CS at rest allowed differentiation between infarcted and other segments with a sensitivity of 79%, specificity of 76%, accuracy of 76%, and an area under the curve (AUC) of 0.81. Additionally, a cutoff value of 477.3 ms for time-to-peak CS at rest

  11. Comparison of the Immunomagnetic Separation/Adenosine Triphosphate Rapid Method and the Modified mTEC Membrane-Filtration Method for Enumeration of Escherichia coli

    Science.gov (United States)

    Brady, Amie M.G.; Bushon, Rebecca N.; Bertke, Erin E.

    2009-01-01

    Water quality at beaches is monitored for fecal indicator bacteria by traditional, culture-based methods that can take 18 to 24 hours to obtain results. A rapid detection method that provides estimated concentrations of fecal indicator bacteria within 1 hour from the start of sample processing would allow beach managers to post advisories or close the beach when the conditions are actually considered unsafe instead of a day later, when conditions may have changed. A rapid method that couples immunomagnetic separation with adenosine triphosphate detection (IMS/ATP rapid method) was evaluated through monitoring of Escherichia coli (E. coli) at three Lake Erie beaches in Ohio (Edgewater and Villa Angela in Cleveland and Huntington in Bay Village). Beach water samples were collected between 4 and 5 days per week during the recreational seasons (May through September) of 2006 and 2007. Composite samples were created in the lab from two point samples collected at each beach and were shown to be comparable substitutes for analysis of two individual samples. E. coli concentrations in composite samples, as determined by the culture-based method, ranged from 4 to 24,000 colony-forming units per 100 milliliters during this study across all beaches. Turbidity also was measured for each sample and ranged from 0.8 to 260 neophelometric turbidity ratio units. Environmental variables were noted at the time of sampling, including number of birds at the beach and wave height. Rainfall amounts were measured at National Weather Service stations at local airports. Turbidity, rainfall, and wave height were significantly related to the culture-based method results each year and for both years combined at each beach. The number of birds at the beach was significantly related to the culture-based method results only at Edgewater during 2006 and during both years combined. Results of the IMS/ATP method were compared to results of the culture-based method for samples by year for each beach

  12. 基于共面薄膜金电极的三磷酸腺苷适体传感器%An Aptamer-based Amperometric Biosensor for Adenosine Triphosphate Detection Based on Coplanar Thin-film Gold Electrode

    Institute of Scientific and Technical Information of China (English)

    姜利英; 王芬芬; 胡杰; 岳保磊; 闫艳霞; 陈青华

    2014-01-01

    Thin-film gold electrodes were fabricated based on MEMS technology. Adenosine triphosphate with mercapto-group was immobilized on a surface of gold electrode via self-assembly. An aptamer-based amperometric biosensor was constructed to measure the concentration of the ATP that using aptamer as the recognition element based on coplanar thin-film gold electrode. Adenosine triphosphate was detected by the characteristic impedance changes based on phosphate backbone of nucleic with negatively charge that electrostatic reject [ Fe( CN) 6 ] 3-/4-. Firstly, under the conditions of bare gold electrode and before and after ATP was added and whether 6-mercapto-1-hexanol was closed on electrode and the different self-assembly time (3, 8, 15, 24 and 30 h),the electrode of impedance changes in electrochemical impedance solution was researched with electrochemical Impedance Spectroscopy. The experiments show that the measurable linearity range of adenosine triphosphate is 1-500 nmol/L, the detection limit is 1 nmol/L and the correlation coefficient was 0 . 9842 when the time of the self-assembly was 24 h and closed gold electrode with 6-mercapto-hexanol. This electrochemical aptasensor was simplicity and has low detection limit and good repeatability.%为了检测三磷酸腺苷( ATP)的浓度,利用微系统( MEMS)技术小批量加工薄膜金电极,采用自组装法将巯基修饰的三磷酸腺苷适体固定到金电极表面,以三磷酸腺苷适体作为识别元件,构建了一种基于共面薄膜金电极的三磷酸腺苷适体传感器。依据核酸磷酸骨架荷负电特性静电排斥[Fe(CN)6]3-/4-所引起的阻抗变化实现对ATP浓度的检测。首先采用电化学阻抗谱法研究了裸金电极及ATP加入前后、6-巯基己醇封闭电极前后以及不同自组装时间(3,8,15,24和30 h)条件下,电极在电化学阻抗溶液中阻抗值变化。然后研究了不同浓度ATP适体传感器的电化学阻抗谱以及适体传感器的线性度和

  13. Oral administration of amino acidic supplements improves protein and energy profiles in skeletal muscle of aged rats: elongation of functional performance and acceleration of mitochondrial recovery in adenosine triphosphate after exhaustive exertion.

    Science.gov (United States)

    Chen Scarabelli, Carol; McCauley, Roy B; Yuan, Zhaokan; Di Rezze, Justin; Patel, David; Putt, Jeff; Raddino, Riccardo; Allebban, Zuhair; Abboud, John; Scarabelli, Gabriele M; Chilukuri, Karuna; Gardin, Julius; Saravolatz, Louis; Faggian, Giuseppe; Mazzucco, Alessandro; Scarabelli, Tiziano M

    2008-06-01

    Sarcopenia is an inevitable age-related degenerative process chiefly characterized by decreased synthesis of muscle proteins and impaired mitochondrial function, leading to progressive loss of muscle mass. Here, we sought to probe whether long-term administration of oral amino acids (AAs) can increase protein and adenosine triphosphate (ATP) content in the gastrocnemius muscle of aged rats, enhancing functional performance. To this end, 6- and 24-month-old male Fisher 344 rats were divided into 3 groups: group A (6-month-old rats) and group B (24-month-old rats) were used as adult and senescent control group, respectively, while group C (24-month-old rats) was used as senescent treated group and underwent 1-month oral treatment with a mixture of mainly essential AAs. Untreated senescent animals exhibited a 30% reduction in total and fractional protein content, as well as a 50% reduction in ATP content and production, compared with adult control rats (p supplementation with mixed AAs significantly improved protein and high-energy phosphate content, as well as the rate of mitochondrial ATP production, conforming their values to those of adult control animals (p energy substrates in the gastrocnemius muscle of treated aged rats paralleled a significant enhancement in functional performance assessed by swim test, with dramatic elongation of maximal exertion times compared with untreated senescent rats (p supplementation with oral AAs improved protein and energy profiles in the gastrocnemius of treated rats, enhancing functional performance and accelerating high-energy phosphate recovery after exhaustive exertion.

  14. The application of adenosine triphosphate bioluminescence assay in the diagnosis of multidrug-resistant ;Mycobacterium tuberculosis%三磷酸腺苷发光法在耐多药结核分枝杆菌诊断中的运用

    Institute of Scientific and Technical Information of China (English)

    刘君; 胡嘉波; 裴豪; 蒯守刚; 陈丽艳

    2013-01-01

    目的:通过与罗氏固体培养法比较,评估三磷酸腺苷发光法检测耐多药结核分枝杆菌的可行性。方法采用三磷酸腺苷发光法与罗氏固体培养法同时检测和分析149例临床分离的结核分枝杆菌。结果三磷酸腺苷发光法与罗氏固体培养法的一致率为92.6%(138/149),差异无统计学意义(χ2=0.57,P=0.45)。三磷酸腺苷发光法检测时间为(6.6±2.1)d,明显快于传统罗氏固体培养法的28 d(t=422.7,P<0.001)。结论与常规检测方法比较,三磷酸腺苷发光法具有快速、简便、准确性高等优点,对耐多药结核患者的早期诊断和耐药结核分枝杆菌流行的控制有很大帮助,适合实验室开展。%Objective To compare with Roche solid culture method,and to evaluate the feasibility of adenosine triphosphate bioluminescence assay for detecting multidrug-resistant Mycobacterium tuberculosis.Methods By Roche solid culture method and adenosine triphosphate bioluminescence assay,149 clinical isolates of Mycobacterium tuber-culosis were determined and analyzed.Results The coincidence rate of adenosine triphosphate bioluminescence assay with Roche solid culture method was 92.6%(138/149),and the difference had no statistical significance (χ2 =0.57, P=0.45).The detection time of adenosine triphosphate bioluminescence assay was (6.6 ±2.1)d,which was faster than that of Roche solid culture method (28 d,t=422.7,P<0.001).Conclusions Compared with the conventional detection methods,adenosine triphosphate bioluminescence assay is simple,rapid and accurate.It is helpful for detecting multidrug-resistant tuberculosis patients and controlling the prevalence of Mycobacterium tuberculosis.It is suitable for clinical laboratory.

  15. Effect of coriaria lactone on adenosine triphosphate-sensitive potassium channels in pyramidal neurons%马桑内酯对锥体神经元三磷酸腺苷敏感钾通道的作用

    Institute of Scientific and Technical Information of China (English)

    邹晓毅; 周华; 周树舜

    2005-01-01

    BACKGROUND: Abnormal neuronal discharge arose from the activation of cell membrane ion channels and transmembrane ion transport. The electric activity of the cells is associated with cell metabolism fundamentally through adenosine triphosphate (ATP)-sensitive potassium(KATP) channels.Currently the involvement of KATP channels in the pathogenesis of epilepsy and the regulation of KATP channels by coriaria lacton (EL) remain unknown.OBJETCIVE: To investigate the changes of cell membrane KATP channels in rat hippocampal neurons in response to CL as an epilepsy-inducing agent, and explore the role of KATP channels in the pathogenesis of epilepsy.DESIGN: Randomized controlled experiment.SETTING: Department of Neurology, West China Hospital Affiliated to Sichuan University, and Teaching and Research Section of Physiology,West China College of Preclinical Medicine and Forensic Medicine of Sichuan University.MATERIALS: This experiment was carried out at Luzhou Medical College between May and December 2000. Hippocampus pyramidal neurons were obtained from neonatal Wistar rats and randomized into normal control group, tetraethylammonium chloride (TEA) group, DNP group, CL group, and electric conductance and dynamics group.METHODS: The hippocampus of newborn Wistar rats was separated under aseptic condition and cultured for 24 hours prior to treatment with 10 μmol/L cytarabine for selective cell culture for 7-10 days. The cells in good growth exhibiting typical morphology of pyramidal neurons were then selected for patch-clamp experiment. The cells in the normal control group were treated with normal saline, which was replaced by 5 mmol/L TEA in TEA group, by 30 μmol/L DNP then 0.5 mol/L ATP in DNP group, and by 1.0 mL/L CL then 1 μmol/L glibenclamide in CL group. In electric conductance and dynamics group, the clamp voltage was firstly adjusted to investigate the channel opening before CL was added to the cells.MAIN OUTCOME MEASURES: ① Activity and curve of neuronal

  16. Effects of Adenosine Triphosphate on Recovered Left Atrium_pulmonary Veins Conduction after Circumferential Pulmonary ;Vein Isolation for Paroxysmal Atrial Fibrillation%ATP对阵发性心房颤动环肺静脉电隔离术后疗效判断的价值

    Institute of Scientific and Technical Information of China (English)

    夏云兵; 黄卫斌

    2014-01-01

    Objective To explore the effects of adenosine triphosphate on recovered left atrium_pulmonary veins conduction after cir-cumferential pulmonary vein isolation (CPVI) for paroxysmal atrial fibrillation.Methods Adenosine triphosphate was injected twice to 75 patients with paroxysmal atrial fibrillation after CPVI in order to induce pulmonary vein conduction recovery.If pulmonary vein po-tential had recovered ,ablation was carried out to reach pulmonary vein isolation again .84 patients with paroxysmal atrial fibrillation after CPVI considered as control group had not been induced.Recurrence rate of atrial fibrillation of two groups were compared.Re-sults Recurrence rates of atrial fibrillation of test group and control group were 21.33% and 30.95% respectively ( P<0.05).Con-clusions Additional ablation for ATP_induced pulmonary vein conduction gaps after CPVI can reduce recurrence rate of paroxysmal a-trial fibrillation.%目的探讨三磷酸腺苷(ATP)对阵发性心房颤动患者环肺静脉电隔离(CPVI)术后左房-肺静脉电传导恢复的影响。方法75例阵发性心房颤动患者在完成消融术后两次给予三磷酸腺苷诱导肺静脉电传导恢复,对肺静脉电位恢复者补充消融重新到达肺静脉隔离。另有对照组84例阵发性心房颤动患者常规完成消融术后不做诱导试验。比较两组患者心房颤动术后复发率。结果试验组心房颤动复发率21.33%,对照组心房颤动复发率30.95%,差异有统计学意义( P<0.05)。结论补充消融三磷酸腺苷“暴露”的肺静脉电传导间隙,可减少阵发性心房颤动的复发率。

  17. Adenosine Triphosphate Stimulates Aquifex aeolicus MutL Endonuclease Activity

    OpenAIRE

    Jerome Mauris; Thomas C Evans

    2009-01-01

    BACKGROUND: Human PMS2 (hPMS2) homologues act to nick 5' and 3' to misincorporated nucleotides during mismatch repair in organisms that lack MutH. Mn(++) was previously found to stimulate the endonuclease activity of these homologues. ATP was required for the nicking activity of hPMS2 and yPMS1, but was reported to inhibit bacterial MutL proteins from Thermus thermophilus and Aquifex aeolicus that displayed homology to hPMS2. Mutational analysis has identified the DQHA(X)(2)E(X)(4)E motif pre...

  18. Adenosine triphosphate stimulates Aquifex aeolicus MutL endonuclease activity.

    Directory of Open Access Journals (Sweden)

    Jerome Mauris

    Full Text Available BACKGROUND: Human PMS2 (hPMS2 homologues act to nick 5' and 3' to misincorporated nucleotides during mismatch repair in organisms that lack MutH. Mn(++ was previously found to stimulate the endonuclease activity of these homologues. ATP was required for the nicking activity of hPMS2 and yPMS1, but was reported to inhibit bacterial MutL proteins from Thermus thermophilus and Aquifex aeolicus that displayed homology to hPMS2. Mutational analysis has identified the DQHA(X(2E(X(4E motif present in the C-terminus of PMS2 homologues as important for endonuclease activity. METHODOLOGIES/PRINCIPAL FINDINGS: We examined the effect ATP had on the Mn(++ induced nicking of supercoiled pBR322 by full-length and mutant A. aeolicus MutL (Aae MutL proteins. Assays were single time point, enzyme titration experiments or reaction time courses. The maximum velocity for MutL nicking was determined to be 1.6+/-0.08x10(-5 s(-1 and 4.2+/-0.3x10(-5 s(-1 in the absence and presence of ATP, respectively. AMPPNP stimulated the nicking activity to a similar extent as ATP. A truncated Aae MutL protein composed of only the C-terminal 123 amino acid residues was found to nick supercoiled DNA. Furthermore, mutations in the conserved C-terminal DQHA(X(2E(X(4E and CPHGRP motifs were shown to abolish Aae MutL endonuclease activity. CONCLUSIONS: ATP stimulated the Mn(++ induced endonuclease activity of Aae MutL. Experiments utilizing AMPPNP implied that the stimulation did not require ATP hydrolysis. A mutation in the DQHA(X(2E(X(4E motif of Aae MutL further supported the role of this region in endonclease activity. For the first time, to our knowledge, we demonstrate that changing the histidine residue in the conserved CPHGRP motif abolishes endonucleolytic activity of a hPMS2 homologue. Finally, the C-terminal 123 amino acid residues of Aae MutL were sufficient to display Mn(++ induced nicking activity.

  19. Determination of adenosine triphosphate in yeast and blood

    NARCIS (Netherlands)

    Steyn-Parvé, Elizabeth P.

    1953-01-01

    A method is described for the determination of ATP in yeast and blood, in which use is made of the decomposition of ATP by myosin adenosinetriphosphatase. ATP is extracted without injury by one minute's boiling at pH 2.5 to 3. Yeast extracts contain myokinase. To destroy this enzyme they are treat

  20. Adenosine triphosphate turnover in humans. Decreased degradation during relative hyperphosphatemia

    International Nuclear Information System (INIS)

    The regulation of ATP metabolism by inorganic phosphate (Pi) was examined in five normal volunteers through measurements of ATP degradation during relative Pi depletion and repletion states. Relative Pi depletion was achieved through dietary restriction and phosphate binders, whereas a Pi-repleted state was produced by oral Pi supplementation. ATP was radioactively labeled by the infusion of [8(14C)]adenine. Fructose infusion was used to produce rapid ATP degradation during Pi depletion and repletion states. Baseline measurements indicated a significant decrease of Pi levels during phosphate depletion and no change in serum or urinary purines. Serum values of Pi declined 20 to 26% within 15 min after fructose infusion in all states. Urine measurements of ATP degradation products showed an eightfold increase within 15 min after fructose infusion in both Pi-depleted and -supplemented states. Urinary radioactive ATP degradation products were fourfold higher and urinary purine specific activity was more than threefold higher during Pi depletion as compared with Pi repletion. Our data indicate that there is decreased ATP degradation to purine end products during a relative phosphate repletion state as compared to a relative phosphate depletion state. These data show that ATP metabolism can be altered through manipulation of the relative Pi state in humans

  1. Adenosine triphosphate-dependent copper transport in human liver

    NARCIS (Netherlands)

    vandenBerg, GJ; Wolters, H; Veld, GI; Slooff, MJH; Heymans, GSA; Kuipers, F; Vonk, RJ

    1996-01-01

    Background/Aim: The recent cloning and sequencing of the Wilson disease gene indicates that hepatic copper (Cu) transport is mediated by a P-type ATPase. The location of this Cu-transporting protein within the hepatocyte is not known; in view of its proposed function and current concepts of hepatic

  2. Effect of adenosine triphosphate on the functional recovery of rats spinal cord injury after transplantation of bone marrow-mesenchymal stem cells%三磷酸腺苷对骨髓间充质干细胞促进脊髓损伤后肢体功能恢复的影响

    Institute of Scientific and Technical Information of China (English)

    刘文忠; 陈永刚; 王栓科; 董平; 马延超

    2013-01-01

    目的 观察三磷酸腺苷(ATP)对骨髓间充质干细胞(BMSCs)促进脊髓损伤(SCI)后肢体功能恢复的影响.方法 将48只体重为240~260 g的SD雌性大鼠,采用改良Allen's打击法制备T12节段SCI模型后,随机分为4组,每组12只,A组(ATP+BMSCs联合移植组)、B组(BMSCs移植组)、C组(ATP移植组)、D组(空白对照组).术后观察大鼠一般情况,于1、3、7、14、21、28d采用Tarlov评分评价后肢功能恢复程度;28 d处死大鼠后取材进行SP染色观察SCI修复情况.结果 术后各组大鼠均出现后肢瘫痪症状,2~3周开始有不同程度恢复,以A组为最快,B、C组次之,D组最差.术后14、21、28 d各组改良Tarlov评分除B、C组比较差异无统计学意义外,其他各组比较差异均有统计学意义(P<0.05).术后28 d SP染色观察显示,A、B组可见存活的BrdU标记阳性BMSCs,A组BrdU阳性细胞数多于B组,差异有统计学意义(P<0.05);C、D组未见BrdU标记阳性细胞.结论 ATP对BMSCs移植修复SCI后肢体功能的恢复具有协同促进作用.%Objective To study the effect of adenosine triphosphate (ATP) in aiding the functional recovery in rats spinal cord injury (SCI) after transplantation of bone marrow-mesenchymal stem cells (BMSCs) delivery on lesion site. Methods 48 experimental adult female Sprague dawley rats (weighing 240~260 g) were made SCI models at Ti2 levels according to the improved Allen's method and were divided into 4 groups randomly. Group A, ATP (40 mg/kg) and BMSCs (6 μL) were injected to the SCI; group B, only BMSCs were injected; group C, only ATP was injected; group D, only laminectomy. The general conditions and their motility of hind limb were regularly scored using the improved Tarlov scale on 1, 3, 7, 14, 21 and 28 days after operation. After 4 weeks, rats were sacrificed, and their spinal cords were examined for 5-bromo-2-deoxy uridine labeled BMSCs by immunostainings. Results Paralysis symptom in hind limb occurred in

  3. Effects of adenosine triphosphate on the proliferation of muscle-derived stem cells in vitro and its mechanism%三磷酸腺苷促进肌源性干细胞增殖的作用及机制研究

    Institute of Scientific and Technical Information of China (English)

    陈燕花; 陈振兵; 翁雨雄; 李涛; 丛晓斌; 王旸; 彭云龙

    2011-01-01

    Objective To investigate the effect of adenosine triphosphate (ATP) on the proliferation of muscle-derived stem cells (MDSCs) in vitro and explore its mechanism.Methods The MDSCs were obtained from mouse skeletal muscle by preplate technique.The cells in the experimental group were cultured in the medium containing ATP( 100 μmol/L),while the cells in the control group were cultured in the medium without ATP.The cell cycle of MDSCs was determined by flow cytometry.The expression of P2Y1 receptor mRNA was detected by RT-PCR.Results After treatment with ATP,the number of cells in the experimental group was much higher than that in the control group at the 3rd day.The G1 % in experimental group was markedly decreased,while S% and PrI value were significantly increased as compared with those in the control group.The time in G1,S and GaM phases in MDSCs were 21.5 hours,4.4 hours and 10.8 hours,respectively,in the experimental group,and were 27.1 hours,9.6 hours and 13.5 hours in the control group.The expression of P2Y1 receptor mRNA was up-regulated after the MDSCs were treated with ATP.The expression level reached the peak at the 3rd day and then it began to decrease,but still remained at high level.Conclusion ATP can stimulate the proliferation of muscle-derived stem cells through P2Y1 receptor,which may be completed by accelerating the transition from G1 to S phase and shorting the time of G1 and S phase.%目的 研究三磷酸腺苷(ATP)促进肌源性干细胞(MDSCs)增殖的作用机制.方法 采用差速贴壁法分离出小鼠MDSCs,将细胞分为两组:实验组(100 μmol/L ATP)和对照组,观察MDSCs的生长情况,用流式细胞仪检测细胞周期,RT-PCR检测MDSCs中ATP受体的表达.结果 ATP作用3d后,实验组的细胞数显著多于对照组.与对照组相比,实验组的G1%(处于G1期的细胞百分率)降低,S%(处于S期的细胞百分率)和PrI值(增殖指数)升高.实验组MDSCs各亚周期(G1期、S期和G2M期)时间分别为21

  4. Quantification of adenosine triphosphate, adenosine diphosphate, and creatine phosphate in sterlet spermatozoa during maturation.

    Science.gov (United States)

    Fedorov, P; Dzyuba, B; Fedorova, G; Grabic, R; Cosson, J; Rodina, M

    2015-11-01

    Sturgeon spermatozoa maturation during their passage through the kidney is a prerequisite for initiation of motility. Samples of sterlet () testicular sperm (TS) were matured in vitro by incubation in seminal fluid (SF) or in SF supplemented with carbonyl cyanide -chlorophenyl hydrazone (CCCP; a respiration uncoupling agent). Sperm was diluted in activation medium (AM) containing 10 m Tris-HCl buffer (pH 8.5) and 0.25% Pluronic, and spermatozoon motility was assessed. Samples were taken and fixed in 3 perchloric acid at 3 points in the incubation process. Quantification of ATP, ADP, and creatine phosphate (CrP) was conducted using liquid chromatography/high-resolution mass spectrometry. We observed a significant decrease in CrP during artificial maturation of TS in SF. In contrast, ATP and ADP were not significantly affected. Addition of CCCP to SF halted maturation and led to significantly lower CrP whereas ADP significantly increased and ATP was unaffected. Dilution of matured and immature TS with AM led to a significant decrease of ATP and CrP and an increase of ADP compared with their levels before dilution, although immature TS were not motile. Energy dependency of TS maturation in sturgeon was confirmed, which suggests that mitochondrial oxidative phosphorylation is needed for maturation of sturgeon TS. PMID:26641041

  5. Evaluation of 99m Tc-MIBI myocardial perfusion imaging with intravenous infusion of adenosine triphosphate in diagnosis of coronary artery disease%静脉注射三磷酸腺苷99mTc-MIBI心肌灌注显像诊断冠心病的评价

    Institute of Scientific and Technical Information of China (English)

    何青; 姚稚明; 于雪; 屈婉莹; 孙福成; 季福绥; 许锋; 钱贻简

    2002-01-01

    目的评价三磷酸腺苷(ATP)药物负荷99mTc-MIBI 心肌灌注断层显像在诊断冠心病中的可行性、安全性和特异性.方法共263例临床诊断为冠心病的病人.所有病人都行ATP负荷的99mTc-MIBI心肌灌注显像(0.16 mg/kg/min, 5 min)检查. 在静脉注射ATP 3分钟时静脉注射20 mCi的99mTc-MIBI, 60分钟后行心肌断层显像.再于48小时后静脉注射99mTc-MIBI 20 mCi, 行静息心肌灌注断层显像.51例病人在2周内行冠状动脉造影以评价ATP介入心肌灌注断层显像诊断冠心病的准确性.在静脉注射ATP的过程中仔细地观察心脏的和非心脏的反应.结果所有病人都完成整个ATP负荷试验.尽管有58.9% 的病人有不同类型的副作用发生,但其程度都不严重.无任何病人需要氨茶碱.最为严重的副作用是II度II型房室传导阻滞(4/263 ),但其持续时间均短暂.ATP介入心肌灌注断层显像诊断冠心病的敏感性和特异性分别为97.1%和82.4%.结论对于不能完成运动试验的病人,ATP负荷心肌灌注断层显像是安全、可行的诊断冠心病的影像学技术.%Objective To evaluate the feasibility, safety and diagnostic accuracy of pharmacologic stress of 99m Technetium-MIBI single-photon emission computed tomography (SPECT) with intravenous adenosine triphosphate (ATP) in patients with suspected coronary artery disease.Methods The study group included 263 patients who were suspected of having coronary artery disease. All patients underwent 99m Tc-MIBI myocardial perfusion imaging with ATP infusion (0.16 mg/kg body weight per min for 5 min). 20 mCi of 99m Tc-MIBI were injected 3 minutes after the start of ATP infusion. Myocardial SPECT images were obtained 60 minutes later. Then, two days later, 20 mCi of 99m Tc-MIBI were administered at rest and myocardial SPECT was repeated. 51 patients also underwent coronary angiography within two weeks for evaluation of sensitivity and specificity of ATP-myocardial perfusion

  6. Expression and clinical significance of thymidylate synthase and adenosine triphosphate-binding cassette superfamily G member protein in advanced gastric carcinoma%进展期胃癌胸苷酸合成酶和三磷酸腺苷结合转运蛋白G超家族成员2的表达及意义

    Institute of Scientific and Technical Information of China (English)

    程浩; 贾喜花; 郑淑君; 张晓伟; 张金库

    2013-01-01

    目的 检测胸苷酸合成酶(TS)和三磷酸腺苷结合转运蛋白G超家族成员2(ABCG2)在进展期胃癌中的表达,探讨其与临床病理特征的关系.方法 收集80例进展期胃癌患者的手术标本,采用免疫组织化学方法,在胃癌组织和相应癌旁正常组织中检测TS和ABCG2的表达,在胃癌组织中检测P-糖蛋白的表达.分析TS、ABCG2表达与临床病理特征、P-糖蛋白表达的相关性.两组间比较行x2检验,多组间比较行Kruskal-Wallis H检验.结果 胃癌组织中TS和ABCG2的总阳性率[85.0%(68/80)和90.0% (72/80)]均高于癌旁正常组织[62.5%(50/80)和78.7% (63/80)],差异均有统计学意义(x2=11.466和16.463,P=0.009和0.001).TS和ABCG2在胃癌组织中的表达水平均与肿瘤TNM分期、分化程度、浸润深度密切相关(TS的x2=30.686、49.823、40.545,ABCG2的x2=48.192、64.722、47.512;P均<0.01),肿瘤分期越晚、分化程度越差、浸润越深,二者的表达水平越高.胃癌组织中TS和ABCG2的表达水平均与P-糖蛋白表达水平相关(x2=43.977和29.509,P均<0.01).结论 TS和ABCG2有可能成为判断胃癌恶性程度、进展、耐药及预后的指标.%Objective To investigate the expressions of thymidylate synthase (TS) and adenosine triphosphate (ATP)-binding cassette superfamily G member 2 (ABCG2) in advanced gastric cancer (GC) and to explore their correlation with clinical pathological features.Methods A total of 80surgical specimens of advanced gastric cancer patients were collected.The expressions of TS and ABCG2 in gastric cancer tissues and adjacent normal gastric tissues were detected by immunohistochemical method.The expression of P-glycoprotein in gastric cancer tissues was also examined.The correlations between TS,ABCG2 and clinical pathological features and P-glycoprotein were analyzed.Chi-square test was performed for two groups comparison and Kruskal-Wallis H test were used for multi-groups comparison.Results The positive rates

  7. Dynamic changes of adenosine triphosphate enzyme activity in encephalon tissue of rat with posttraumatic stress disorder psycho and behaviour abnormity%创伤后应激障碍样情感行为异常大鼠脑组织ATP酶活性的动态变化

    Institute of Scientific and Technical Information of China (English)

    肖凯

    2004-01-01

    AIM:To discuss the pathophysiology basis of posttraumatic stress disorder(PTSD like) psycho and behaviour abnormity in attempt to provide a new method in treatments. METHODS:Seventy two male Wistar rats were randomly divided into three groups:hippocampus under threshold electric stimulation group(SE,n=32),hippocampus electrode burying control group(CE,n=32) and normal control group(NC,n=8).Hippocampus were continuously stimulated by constant monopulse electricity,with 25 Hz frequency,1 ms wave length,10 s cluster length,7 min cluster interval and 100 μ A strength under eclampsia threshold. The enzymatic activity changes of Na+ K+ adenosine triphosphate enzyme(ATPase) and Ca2+ ATPase in hippocampal homogenate of the experimental animals and mitochondria were detected in quantitation.RESULTS:The enzymatic activity of Na+-K+-ATPase in hippocampus mitochondria decreased obviously(0.56±0.15)mmol/(kg·s)(F=4.348,P<0.01) in under-threshold electric stimulation group atfer 12 hours of electric timulations as well as(0.61±0.17) mmol/(kg·s) (P<0.05) after 48 hours,which were significantly lower than NC group (0.84±0.22) mmol/(kg·s) the enzymatic activity of Ca2+-ATPase in hippocampus mitochondria also decreased obviously into (0.53±0.14) mmol/(kg·s) (F=4.999,P<0.05) after 24 hours of electric stimulations as well as (0.60±0.16) mmol/(kg·s) after 72 hours, which were significantly lower than NC group (0.83±0.22) mmol/(kg·s).CONCLUSION:Functional damages of the hippocampus, especially the Na K pump and Ca2+ pump in hippocampal mitochondria may have an important significance in the occurrence and development of long term PTSD like psycho and behaviour abnormity in experimental animals.%目的:探讨创伤后应激障碍( posttraumatic stress disorder,PTSD)样精神与行为异常的病理生理基础,为其治疗途径提供新思路. 方法:将 72只雄性 Wistar大鼠随机分组为海马阈下电刺激组( SE, n=32)、海马电极埋植对照组( CE, n=32)

  8. Prolonged donor hearts preservation with pinacidil: the role of mitochondria anti mitochondrial adenosine triphosphate-sensitive potassium channels%含钾通道开放剂的HTK液对大鼠心功能以及线粒体结构和功能的影响

    Institute of Scientific and Technical Information of China (English)

    杨柳青; 喻田; 刘兴奎; 余志豪

    2009-01-01

    5HD group), (4) the group of HTK solution containing pinacidil, Hoechst-Marion-Roussel 1098 (HMR1098, a selective sarcolemmal KATP channel blocker, the 1098 group),and (5) the group of HTK solution containing pinacidil, 5HD and HMR1098 (the 5HD + 1098 group). The Langendorff perfusion models were established. All hearts were arrested with the above-mentioned five preservation solutions in a Langendorff apparatus respectively and subsequently dipped into the same solution for 8 h at 4 ℃ followed by 60 min of reperfusion. The hemodynamics,mitochondrial respiratory function,ATP levels,cardiac troponin Ⅰ release and myocardial uttrastructure were examined. Results Compared with the other groups, heart performance parameters, mitochondria]respiratory enzyme activity and myocardial ATP contents in the Pi group were significantly improved as well as the myocardial mitochondria Flameng score. The protection was almost abolished by the addition of 5HD and moderately decreased by HMR1098. Conclusion Pinacidil may further improve the myocardial protection efficacy of donor heart preservation. Energy status preservation is one of important mechanisms of pinacidil and the effect depends more on mitochondrial than on sarcolemmal potassium adenosine triphosphate channels.

  9. Adenosine and adenosine receptors: Newer therapeutic perspective

    Directory of Open Access Journals (Sweden)

    Manjunath S

    2009-01-01

    Full Text Available Adenosine, a purine nucleoside has been described as a ′retaliatory metabolite′ by virtue of its ability to function in an autocrine manner and to modify the activity of a range of cell types, following its extracellular accumulation during cell stress or injury. These effects are largely protective and are triggered by binding of adenosine to any of the four adenosine receptor subtypes namely A1, A2a, A2b, A3, which have been cloned in humans, and are expressed in most of the organs. Each is encoded by a separate gene and has different functions, although overlapping. For instance, both A1 and A2a receptors play a role in regulating myocardial oxygen consumption and coronary blood flow. It is a proven fact that adenosine plays pivotal role in different physiological functions, such as induction of sleep, neuroprotection and protection against oxidative stress. Until now adenosine was used for certain conditions like paroxysmal supraventricular tachycardia (PSVT and Wolff Parkinson White (WPW syndrome. Now there is a growing evidence that adenosine receptors could be promising therapeutic targets in a wide range of conditions including cardiac, pulmonary, immunological and inflammatory disorders. After more than three decades of research in medicinal chemistry, a number of selective agonists and antagonists of adenosine receptors have been discovered and some have been clinically evaluated, although none has yet received regulatory approval. So this review focuses mainly on the newer potential role of adenosine and its receptors in different clinical conditions.

  10. 神经生长因子及三磷酸腺苷联合应用修复大鼠周围神经损伤及对失神经肌肉的作用%Combined used of nerve growth factor and adenosine triphosphate for repair of peripheral nerve injury and its influence on the denervated muscle

    Institute of Scientific and Technical Information of China (English)

    何爱咏; 闫振升; 王如成

    2010-01-01

    Objective To investigate the unification effect of rat nerve growth factor(NGF)and adenosine triphosphate(ATP)on repair of the peripheral nerve injury and the denervated muscle.Methods Ninety-six healthy SD rats weighing(250±15)g were randomly divided into NGF+ATP group,NGF group,ATP group and NS group.The sciatic nerves were cut for 3 mm,and were connected with silicone tube to create the nerve regeneration room.Then,all rats were intraperitoneally injected with NS0.4ml,ATP0.4ml(1 mg/ml),NGF 0.4 ml(0.2 μg/ml),NGF+ATP 0.4 ml(ATP1 mg/ml,NGF 0.2 μg/ml)separately once every three days.Six rats from each group were selected at 2,4,6 and 8 weeks after operation for sciatic nerve index(SFI)detection,gross observation and electrophysiological test;the specimens were obtained from the sacrificed rats for nerve regeneration,gastrocnemius muscle wet weight,fiber diameter and cross-sectional area of the gastrocnemius muscle(by HE staining).ResultsAt 2,4,6 and 8 weeks after operation,every six rats were chosen to be tested.The SFI,nerve conduction velocity and wet weight of the muscle of NGF+ATP group were better than those of the other three groups(P < 0.05).The swelling of the rat toes of NGF+ATP group was slighter than that of NGF group and ATP group,with no loss of toes found in NGF+ATP group.At the 2nd week after operation,new nerve fibers were observed in the regeneration room,with no connection of the nerve fibers.The nerve fibers crossed the regeneration room at 4,6 and 8 weeks after operation.Compared with other three groups,the nerve growth condition was better in NGF+ATP group,with slighter adhesion and inflammation of nerve fibers.The growth condition of the nerve fibers of NGF group was better than ATP group,and that of NGF group and ATP group was better than NS group.At 2,4,6 and 8 weeks after operation,the electrophysiological condition and wet weight of muscle in NGF group was better than those in ATP group.While the SFI,the cross area and diameter of the

  11. A High-Affinity Adenosine Kinase from Anopheles Gambiae

    Energy Technology Data Exchange (ETDEWEB)

    M Cassera; M Ho; E Merino; E Burgos; A Rinaldo-Matthis; S Almo; V Schramm

    2011-12-31

    Genome analysis revealed a mosquito orthologue of adenosine kinase in Anopheles gambiae (AgAK; the most important vector for the transmission of Plasmodium falciparum in Africa). P. falciparum are purine auxotrophs and do not express an adenosine kinase but rely on their hosts for purines. AgAK was kinetically characterized and found to have the highest affinity for adenosine (K{sub m} = 8.1 nM) of any known adenosine kinase. AgAK is specific for adenosine at the nucleoside site, but several nucleotide triphosphate phosphoryl donors are tolerated. The AgAK crystal structure with a bound bisubstrate analogue Ap{sub 4}A (2.0 {angstrom} resolution) reveals interactions for adenosine and ATP and the geometry for phosphoryl transfer. The polyphosphate charge is partly neutralized by a bound Mg{sup 2+} ion and an ion pair to a catalytic site Arg. The AgAK structure consists of a large catalytic core in a three-layer {alpha}/{beta}/{alpha} sandwich, and a small cap domain in contact with adenosine. The specificity and tight binding for adenosine arise from hydrogen bond interactions of Asn14, Leu16, Leu40, Leu133, Leu168, Phe168, and Thr171 and the backbone of Ile39 and Phe168 with the adenine ring as well as through hydrogen bond interactions between Asp18, Gly64, and Asn68 and the ribosyl 2'- and 3'-hydroxyl groups. The structure is more similar to that of human adenosine kinase (48% identical) than to that of AK from Toxoplasma gondii (31% identical). With this extraordinary affinity for AgAK, adenosine is efficiently captured and converted to AMP at near the diffusion limit, suggesting an important role for this enzyme in the maintenance of the adenine nucleotide pool. mRNA analysis verifies that AgAK transcripts are produced in the adult insects.

  12. Differential modulation of ATP-induced calcium signalling by A1 and A2 adenosine receptors in cultured cortical astrocytes

    OpenAIRE

    Alloisio, Susanna; Cugnoli, Carlo; Ferroni, Stefano; Nobile, Mario

    2004-01-01

    Despite the accumulating evidence that under various pathological conditions the extracellular elevation of adenine-based nucleotides and nucleosides plays a key role in the control of astroglial reactivity, how these signalling molecules interact in the regulation of astrocyte function is still largely elusive.The action of the nucleoside adenosine in the modulation of the intracellular calcium signalling ([Ca2+]i) elicited by adenosine 5′-triphosphate (ATP)-induced activation of P2 purinoce...

  13. Adenosine Receptors and Asthma

    OpenAIRE

    Wilson, Constance N; Nadeem, Ahmed; Spina, Domenico; Brown, Rachel; Page, Clive P.; Jamal Mustafa, S.

    2009-01-01

    The pathophysiological processes underlying respiratory diseases like asthma are complex, resulting in an overwhelming choice of potential targets for the novel treatment of this disease. Despite this complexity, asthmatic subjects are uniquely sensitive to a range of substances like adenosine, thought to act indirectly to evoke changes in respiratory mechanics and in the underlying pathology, and thereby to offer novel insights into the pathophysiology of this disease. Adenosine is of partic...

  14. Effects of paeonol on lipopolysaccharide/adenosine 5′-triphosphate induced NLRP3 inflammasome activation in primary rat microglia%丹皮酚对脂多糖/三磷酸腺苷诱导的小胶质细胞NLRP3炎症小体激活的影响

    Institute of Scientific and Technical Information of China (English)

    王伟; 戴敏; 徐忠东

    2014-01-01

    目的:观察丹皮酚( Pae)对脂多糖( LPS)与三磷酸腺苷( ATP)诱导大鼠原代小胶质细胞NLRP3炎症小体激活的影响,探讨Pae对小胶质细胞炎症反应的抑制作用及其具体机制。方法采用白细胞分化抗原11b(CD11b)免疫荧光染色法鉴定小胶质细胞;采用ELISA法测定培养液中白细胞介素-1β( IL-1β)的水平;采用Western blot检测细胞NLRP3、ASC和caspase-1蛋白表达水平;采用2′,7′-二氯二氢荧光素二乙酯( DCFH-DA)为荧光探针检测细胞内活性氧( ROS)的水平。结果 LPS(0.5 mg·L-1)/ATP(5 mmol·L-1)能增加小胶质细胞ROS及上清液IL-1β水平,上调细胞NLRP3、ASC和caspase-1蛋白水平;Pae能减少细胞 ROS和上清液IL-1β水平,抑制LPS和ATP双信号上调的NLRP3、ASC和caspase-1蛋白水平。结论 Pae能抑制LPS/ATP激活的小胶质细胞NLRP3炎症小体,减少细胞上清液IL-1β水平,Pae对NLRP3炎症小体抑制作用可能与其下调小胶质细胞ROS水平有关。%Aim To investigate the effects of paeonol on lipopolysaccharide ( LPS) and adenosine 5′-triphos-phate ( ATP) induced NLRP3 inflammasome activation in primary rat microglia and the mechanisms responsi-ble for this anti-inflammatory effects. Methods Pri-mary rat microglia were identified immunohistochemi-cally using the cluster of differentiation 11 b ( CD11 b ) antibody. Proinflammatory cytokine IL-1β was deter-mined by ELISA. Western blot was performed to ob-serve the protein expression of NLRP3 , ASC and caspase-1 in cultured primary rat microglia. The level of intracellular reactive oxygen species ( ROS) was mo-nitored by using the fluorescent probe 2′, 7′-dichlo-rofluorescein diacetate ( DCFH-DA ) . Results LPS (0. 5 mg · L-1 )/ATP ( 5 mmol · L-1 ) significantly increased intracellular ROS level and IL-1β secretion and upregulated NLRP3 , ASC and caspase-1 protein expression in primary rat microglia. Paeonol signifi-cantly decreased intracellular ROS level and

  15. Adenosine and sleep

    International Nuclear Information System (INIS)

    Behavioral and biochemical approaches have been used to determine the relative contribution of endogenous adenosine and adenosine receptors to the sleep-wake cycle in the rat. Adenosine concentrations in specific areas of the rat brain were not affected by 24 hours of total sleep deprivation, or by 24 or 48 hours of REM sleep deprivation. In order to assess the effect of REM sleep deprivation on adenosine A1 receptors, 3H-L-PIA binding was measured. The Bmax values for 3H-L-PIA binding to membrane preparations of the cortices and corpus striata from 48 hour REM sleep-deprived animals were increased 14.8% and 23%, respectively. These increases were not maintained following the cessation of sleep deprivation and recovered within 2 hours. The results of a 96 hour REM deprivation experiment were similar to those of the 48 hour REM sleep deprivation experiment. However, these increases were not evident in similar structures taken from stress control animals, and conclusively demonstrated that the changes in 3H-L-PIA binding resulted from REM sleep deprivation and not from stress

  16. Adenosine and sleep

    Energy Technology Data Exchange (ETDEWEB)

    Yanik, G.M. Jr.

    1987-01-01

    Behavioral and biochemical approaches have been used to determine the relative contribution of endogenous adenosine and adenosine receptors to the sleep-wake cycle in the rat. Adenosine concentrations in specific areas of the rat brain were not affected by 24 hours of total sleep deprivation, or by 24 or 48 hours of REM sleep deprivation. In order to assess the effect of REM sleep deprivation on adenosine A/sub 1/ receptors, /sup 3/H-L-PIA binding was measured. The Bmax values for /sup 3/H-L-PIA binding to membrane preparations of the cortices and corpus striata from 48 hour REM sleep-deprived animals were increased 14.8% and 23%, respectively. These increases were not maintained following the cessation of sleep deprivation and recovered within 2 hours. The results of a 96 hour REM deprivation experiment were similar to those of the 48 hour REM sleep deprivation experiment. However, these increases were not evident in similar structures taken from stress control animals, and conclusively demonstrated that the changes in /sup 3/H-L-PIA binding resulted from REM sleep deprivation and not from stress.

  17. Adenosine and Sleep

    OpenAIRE

    Bjorness, Theresa E.; Greene, Robert W.

    2009-01-01

    Over the last several decades the idea that adenosine (Ado) plays a role in sleep control was postulated due in large part to pharmacological studies that showed the ability of Ado agonists to induce sleep and Ado antagonists to decrease sleep. A second wave of research involving in vitro cellular analytic approaches and subsequently, the use of neurochemical tools such as microdialysis, identified a population of cells within the brainstem and basal forebrain arousal centers, with activity t...

  18. Vasodilator effects of adenosine on retinal arterioles in streptozotocin-induced diabetic rats.

    Science.gov (United States)

    Nakazawa, Taisuke; Mori, Asami; Saito, Maki; Sakamoto, Kenji; Nakahara, Tsutomu; Ishii, Kunio

    2008-02-01

    Adenosine is a potent vasodilator of retinal blood vessels and is implicated to be a major regulator of retinal blood flow during metabolic stress, but little is known about the impact of diabetes on the role of adenosine in regulation of retinal hemodynamics. Therefore, we examined how diabetes affects adenosine-induced vasodilation of retinal arterioles. Male Wistar rats were treated with streptozotocin (80 mg/kg, intraperitoneally), and experiments were performed 6-8 weeks later. Rats were treated with tetrodotoxin (50 microg/kg, intravenously [i.v.]) to eliminate any nerve activity and prevent movement of the eye and infused with methoxamine continuously to maintain adequate systemic circulation. Fundus images were captured with a digital camera that was equipped with a special objective lens, and diameters of retinal arterioles were measured. Adenosine increased diameters of retinal arterioles and decreased systemic blood pressure. These responses were significantly attenuated by the nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (30 mg/kg, i.v.) and the adenosine triphosphate-dependent K+ (K(ATP)) channel blocker glibenclamide (20 mg/kg, i.v.). The depressor responses to adenosine were reduced in diabetic rats, whereas diabetes did not alter vasodilation of retinal arterioles to adenosine. In contrast, both depressor response and vasodilation of retinal arteriole to acetylcholine were reduced in diabetic rats. The retinal vasodilator responses to adenosine and acetylcholine observed in diabetic rats were diminished by N(G)-nitro-L-arginine methyl ester. There were no differences in the responses to pinacidil, a K(ATP) channel opener, between the diabetic and nondiabetic rats. These results suggest that both the activation of nitric oxide synthase and opening of K(ATP) channels contribute to the vasodilator effects of adenosine in rats in vivo. However, diabetes has no significant impact on the vasodilation mediated by these mechanisms in

  19. Adenosine receptors in rat and human pancreatic ducts stimulate chloride transport

    DEFF Research Database (Denmark)

    Novak, Ivana; Hede, Susanne; Hansen, Mette

    2007-01-01

    Previously, we have shown that pancreatic acini release adenosine triphosphate (ATP) and ATP-handling enzymes, and pancreatic ducts express various purinergic P2 receptors. The aim of the present study was to establish whether pancreatic ducts also express adenosine receptors and whether...... these could be involved in secretory processes, which involve cystic fibrosis transmembrane regulator (CFTR) Cl(-) channels or Ca(2+)-activated Cl(-) channels and [Formula: see text] transporters. Reverse transcriptase polymerase chain reaction analysis on rat pancreatic ducts and human duct cell......) for duct cell lines. Whole-cell patch-clamp recordings on rat pancreatic ducts showed that, in about half of the recordings, adenosine depolarized the membrane voltage, and this was because of the opening of Cl(-) channels. Using a Cl(-)-sensitive fluorophore and single-cell imaging on duct cell lines...

  20. CHARACTERISTICS AND OPTIMAL WORKING CONDITIONS OF AMPEROMETRIC BIOSENSOR FOR ADENOSINE TRIPHOSPHATE DETERMINATION

    Directory of Open Access Journals (Sweden)

    Kucherenko I. S.

    2014-02-01

    Full Text Available Analytical characteristics of a biosensor based on glucose oxidase and hexokinase and intended for ATP determination were studied. Platinum disc electrodes were used as amperometric transducers. Range of working potentials for biosensor functioning was shown. An optimal time of enzymes immobilization was determined. Optimal conditions for biosensor functioning during work with biological fluids were selected. Biosensor work in three buffer solutions (PBS, tris and HEPES was investigated and it was shown that it was possible to obtain various operational characteristics of the biosensor depending on tasks that are assigned to it by varying the composition of sample. Reproducibility of biosensor responses to ATP and glucose during a day and of biosensor preparation was shown. The proposed biosensor can be further used for analysis of glucose and ATP content in water solutions.

  1. An adenosine triphosphate-dependent calcium uptake pump in human neutrophil lysosomes.

    OpenAIRE

    Klemper, M S

    1985-01-01

    Regulation of the cytosolic free calcium concentration is important to neutrophil function. In these studies, an ATP-dependent calcium uptake pump has been identified in human neutrophil lysosomes. This energy-dependent Ca++ uptake pump has a high affinity for Ca++ (Michaelis constant [Km] Ca++ = 107 nM) and a maximum velocity (Vmax) of 5.3 pmol/mg of protein per min. ATP was the only nucleotide that supported Ca++ uptake by lysosomes. The Km for ATP was 177 microM. ATP-dependent Ca++ uptake ...

  2. Adenosine triphosphate-dependent calcium pump in the plasma membrane of guinea pig and human neutrophils.

    OpenAIRE

    Lagast, H; Lew, P D; Waldvogel, F A

    1984-01-01

    Changes in cytosolic free Ca may function as a second messenger in neutrophils. Since the plasma membrane seems to be a major regulator of intracellular Ca in many cells, we characterized an energy-dependent Ca transport system in plasma membrane-enriched fractions ("podosomes") from phorbol myristate acetate-stimulated guinea pig and human neutrophils. The active Ca transport system in guinea pig podosomes exhibited a high affinity for Ca (Michaelis constant [Km]Ca 280 +/- 120 nM) and a maxi...

  3. Sperm morphology, adenosine triphosphate (ATP) concentration and swimming velocity: unexpected relationships in a passerine bird.

    Science.gov (United States)

    Bennison, Clair; Hemmings, Nicola; Brookes, Lola; Slate, Jon; Birkhead, Tim

    2016-08-31

    The relationship between sperm energetics and sperm function is poorly known, but is central to our understanding of the evolution of sperm traits. The aim of this study was to examine how sperm morphology and ATP content affect sperm swimming velocity in the zebra finch Taeniopygia guttata We exploited the high inter-male variation in this species and created extra experimental power by increasing the number of individuals with very long or short sperm through artificial selection. We found a pronounced quadratic relationship between total sperm length and swimming velocity, with velocity increasing with length up to a point, but declining in the very longest sperm. We also found an unexpected negative association between midpiece length and ATP content: sperm with a short midpiece generally contained the highest concentration of ATP. Low intracellular ATP is therefore unlikely to explain reduced swimming velocity among the very longest sperm (which tend to have a shorter midpiece). PMID:27559067

  4. Adsorption of nucleotides on biomimetic apatite: The case of adenosine 5‧ triphosphate (ATP)

    Science.gov (United States)

    Hammami, Khaled; El-Feki, Hafed; Marsan, Olivier; Drouet, Christophe

    2016-01-01

    ATP is a well-known energy supplier in cells. The idea to associate ATP to pharmaceutical formulations/biotechnological devices to promote cells activity by potentially modulating their microenvironment thus appears as an appealing novel approach. Since biomimetic nanocrystalline apatites have shown great promise for biomedical applications (bone regeneration, cells diagnostics/therapeutics, …), thanks to a high surface reactivity and an intrinsically high biocompatibility, the present contribution was aimed at exploring ATP/apatite interactions. ATP adsorption on a synthetic carbonated nanocrystalline apatite preliminarily characterized (by XRD, FTIR, Raman, TG-DTA and SEM-EDX) was investigated in detail, pointing out a good agreement with Sips isothermal features. Adsorption characteristics were compared to those previously obtained on monophosphate nucleotides (AMP, CMP), unveiling some specificities. ATP was found to adsorb effectively onto biomimetic apatite: despite smaller values of the affinity constant KS and the exponential factor m, larger adsorbed amounts were reached for ATP as compared to AMP for any given concentration in solution. m tissue engineering, intracellular drug delivery, …).

  5. Cellular and biophysical evidence for interactions between adenosine triphosphate and P-glycoprotein substrates

    DEFF Research Database (Denmark)

    Abraham, E H; Shrivastav, B; Salikhova, A Y;

    2001-01-01

    P-glycoprotein is involved with the removal of drugs, most of them cations, from the plasma membrane and cytoplasm. Pgp is also associated with movement of ATP, an anion, from the cytoplasm to the extracellular space. The central question of this study is whether drug and ATP transport associated...... with the expression of Pgp are in any way coupled. We have measured the stoichiometry of transport coupling between drug and ATP release. The drug and ATP transport that is inhibitable by the sulfonylurea compound, glyburide (P. E. Golstein, A. Boom, J. van Geffel, P. Jacobs, B. Masereel, and R. Beauwens, Pfluger...

  6. The pathway of inorganic-phosphate efflux from isolated liver mitochondria during adenosine triphosphate hydrolysis.

    Science.gov (United States)

    Tyler, D D

    1980-12-15

    1. The distribution of P(i) between mitochondria and suspending medium during uncoupler-stimulated hydrolysis of ATP by rat liver mitochondria [Tyler (1969) Biochem. J.111, 665-678] has been reinvestigated, by using either mersalyl or N-ethylmaleimide as inhibitors of P(i) transport and either buffered sucrose/EDTA or LiCl/EGTA solutions as suspending medium. More than 75% of the total P(i) liberated was retained in mitochondria treated with either inhibitor at all ATP concentrations tested (0.2-2.5mm). With low ATP concentrations and mersalyl-treated mitochondria incubated in sucrose/EDTA, virtually all the P(i) liberated was retained in the mitochondria. 2. Larger amounts of P(i) appeared in the suspending medium during ATPase activity, despite the presence of N-ethylmaleimide, when LiCl/EGTA was used as suspending medium compared with sucrose/EDTA. Two sources of this P(i) were identified: (a) a slow efflux of P(i) from mitochondria to suspending medium despite the presence of N-ethylmaleimide; (b) a slow ATPase activity insensitive to carboxyatractyloside, which was stimulated by added Mg(2+), partially inhibited by oligomycin or efrapeptin and strongly inhibited by EDTA. 3. It is concluded that liver mitochondria preparations contain two distinct forms of ATPase activity. The major activity is associated with coupled mitochondria of controlled permeability to adenine nucleotides and P(i) and is stimulated strongly by uncoupling agents. The minor activity is associated with mitochondria freely permeable to adenine nucleotides and P(i), is unaffected by uncoupling agents and is activated by endogenous or added Mg(2+). 4. When mitochondria treated with mersalyl were incubated in buffered sucrose solution, almost all the P(i) liberated was recovered in the suspending medium, unless inhibitors of P(i)-induced large-amplitude swelling such as EDTA, EGTA, antimycin, rotenone, nupercaine or Mg(2+) were added. Thus the loss of the specific permeability properties of the mitochondrial inner membrane associated with large-amplitude swelling also influences the extent of P(i) retention during ATPase activity. 5. The results confirm the previous conclusion (Tyler, 1969) that the P(i) transporter provides the sole pathway for P(i) efflux during uncoupler-stimulated ATP hydrolysis by mitochondria. It is concluded that more recent hypotheses concerning the influence of Mg(2+) on mersalyl inhibition of the P(i) transporter [Siliprandi, Toninello, Zoccaroto & Bindoli (1975) FEBS Lett. 51, 15-17] and a postulated role of the adenine nucleotide exchange carrier in P(i) efflux [Reynafarje & Lehninger (1978) Proc. Natl. Acad. Sci. U.S.A.75, 4788-4792] are erroneous and should be discarded. PMID:6453587

  7. ADENOSINE TRIPHOSPHATE-DEPENDENT COPPER TRANSPORT IN ISOLATED RAT-LIVER PLASMA-MEMBRANES

    NARCIS (Netherlands)

    INTVELD, G; VANDENBERG, GJ; MULLER, M; KUIPERS, F; VONK, RJ

    1995-01-01

    The process of hepatobiliary copper (Cu) secretion is still poorly understood: Cu secretion as a complex with glutathione and transport via a lysosomal pathway have been proposed. The recent cloning and sequencing of the gene for Wilson disease indicates that Cu transport in liver cells may be media

  8. Studies on adenosine triphosphate transphosphorylases. Amino acid sequence of rabbit muscle ATP-AMP transphosphorylase.

    Science.gov (United States)

    Kuby, S A; Palmieri, R H; Frischat, A; Fischer, A H; Wu, L H; Maland, L; Manship, M

    1984-05-22

    The total amino acid sequence of rabbit muscle adenylate kinase has been determined, and the single polypeptide chain of 194 amino acid residues starts with N-acetylmethionine and ends with leucyllysine at its carboxyl terminus, in agreement with the earlier data on its amino acid composition [Mahowald, T. A., Noltmann, E. A., & Kuby, S. A. (1962) J. Biol. Chem. 237, 1138-1145] and its carboxyl-terminus sequence [Olson, O. E., & Kuby, S. A. (1964) J. Biol. Chem. 239, 460-467]. Elucidation of the primary structure was based on tryptic and chymotryptic cleavages of the performic acid oxidized protein, cyanogen bromide cleavages of the 14C-labeled S-carboxymethylated protein at its five methionine sites (followed by maleylation of peptide fragments), and tryptic cleavages at its 12 arginine sites of the maleylated 14C-labeled S-carboxymethylated protein. Calf muscle myokinase, whose sequence has also been established, differs primarily from the rabbit muscle myokinase's sequence in the following: His-30 is replaced by Gln-30; Lys-56 is replaced by Met-56; Ala-84 and Asp 85 are replaced by Val-84 and Asn-85. A comparison of the four muscle-type adenylate kinases, whose covalent structures have now been determined, viz., rabbit, calf, porcine, and human [for the latter two sequences see Heil, A., Müller, G., Noda, L., Pinder, T., Schirmer, H., Schirmer, I., & Von Zabern, I. (1974) Eur. J. Biochem. 43, 131-144, and Von Zabern, I., Wittmann-Liebold, B., Untucht-Grau, R., Schirmer, R. H., & Pai, E. F. (1976) Eur. J. Biochem. 68, 281-290], demonstrates an extraordinary degree of homology.(ABSTRACT TRUNCATED AT 250 WORDS)

  9. Lactate and Adenosine Triphosphate in the Extender Enhance the Cryosurvival of Rat Epididymal Sperm

    OpenAIRE

    Yamashiro, Hideaki; Toyomizu, Masaaki; Kikusato, Motoi; Toyama, Natsuki; Sugimura, Satoshi; Hoshino, Yumi; Abe, Hiroyuki; Moisyadi, Stefan; Sato, Eimei

    2010-01-01

    We evaluated the cryosurvival of rat epididymal sperm preserved in raffinose–modified Krebs-Ringer bicarbonate–egg yolk extender supplemented with various energy-yielding substrates (glucose, pyruvate, lactate, and ATP) and assessed the effect on sperm oxygen consumption. The incubation of sperm at 37 °C for 10 min in lactate-free extender decreased sperm motility and oxygen consumption before and after thawing compared with those of sperm in glucose- and pyruvate-free mediums. We then focuse...

  10. Synthesis and degradation of adenosine triphosphate in cod ( Gadus morhua ) at subzero temperatures

    DEFF Research Database (Denmark)

    Cappeln, Gertrud; Nielsen, Jette; Jessen, Flemming

    1999-01-01

    This study has demonstrated that the extraction step is very important when analysing ATP and its degradation products. An important factor is whether the sample is fresh, frozen or thawed when homogenised since thawing of the sample will lead to rapid loss of ATP. During frozen storage it was...... degrees C. Furthermore, it was found that in whole cod ATP could be synthesised at a significant rate at -7 degrees C. (C) 1999 Society of Chemical Industry....

  11. Allosteric activation of brain hexokinase by magnesium ions and by magnesium ion--adenosine triphosphate complex.

    Science.gov (United States)

    Bachelard, H S

    1971-11-01

    1. Substrate-saturation curves of brain hexokinase for MgATP(2-) were sigmoidal at sub-saturating concentrations of glucose when the Mg(2+)/ATP ratio was maintained at 1:1. Under identical conditions, except that Mg(2+) was present in excess, hyperbolic curves were observed. 2. The number of binding sites (calculated from Hill plots) is 1.8 at a Mg(2+)/ATP ratio 1:1, and 1.0 with excess of Mg(2+). The apparent K(m) for MgATP(2-) is 6.5x10(-4)m at a Mg(2+)/ATP ratio 1:1, and 3.5x10(-4)m with excess of Mg(2+). 3. Interdependence between substrate-binding sites was indicated by the effects of varying the concentration of glucose. The sigmoidality and deviation from Michaelis-Menten kinetics at a Mg(2+)/ATP ratio 1:1 became less pronounced with increasing glucose concentration. Also, although substrate-saturation curves for glucose were hyperbolic when the Mg(2+)/ATP ratio was 1:1, reciprocal plots were non-linear. These were linear with excess of Mg(2+). 4. High concentrations of Mg(2+) (Mg(2+)/ATP ratios above 5:1) were inhibitory. 5. The results are taken to indicate homotropic co-operative binding of MgATP(2-) and that Mg(2+) is an allosteric activator. Possible implications in regulation are discussed.

  12. Adenosine and the adenosine A2A receptor agonist, CGS21680, upregulate CD39 and CD73 expression through E2F-1 and CREB in regulatory T cells isolated from septic mice.

    Science.gov (United States)

    Bao, Rui; Shui, Xianqi; Hou, Jiong; Li, Jinbao; Deng, Xiaoming; Zhu, Xiaoyan; Yang, Tao

    2016-09-01

    The number of regulatory T cells (Treg cells) and the expression of ectonucleoside triphosphate diphosphohydrolase 1 (ENTPD1; also known as CD39) and 5'-ectonucleotidase (NT5E; also known as CD73) on the Treg cell surface are increased during sepsis. In this study, to determine the factors leading to the high expression of CD39 and CD73, and the regulation of the CD39/CD73/adenosine pathway in Treg cells under septic conditions, we constructed a mouse model of sepsis and separated the Treg cells using a flow cytometer. The Treg cells isolated from the peritoneal lavage and splenocytes of the mice were treated with adenosine or the specific adenosine A2A receptor agonist, CGS21680, and were transfected with specific siRNA targeting E2F transcription factor 1 (E2F-1) or cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB), which are predicted transcription regulatory factors of CD39 or CD73. The regulatory relationships among these factors were then determined by western blot analysis and dual-luciferase reporter assay. In addition, changes in adenosine metabolism were measured in the treated cells. The results revealed that adenosine and CGS21680 significantly upregulated CD39 and CD73 expression (PTreg cell surface during sepsis. Adenosine and its A2A receptor agonist served as the signal transducer factors of the CD39/CD73/adenosine pathway, accelerating adenosine generation. Our study may benefit further research on adenosine metabolism for the treatment of sepsis. PMID:27430240

  13. Ecto-nucleoside triphosphate diphosphohydrolase 2 modulates local ATP-induced calcium signaling in human HaCaT keratinocytes.

    Directory of Open Access Journals (Sweden)

    Chia-Lin Ho

    Full Text Available Keratinocytes are the major building blocks of the human epidermis. In many physiological and pathophysiological conditions, keratinocytes release adenosine triphosphate (ATP as an autocrine/paracrine mediator that regulates cell proliferation, differentiation, and migration. ATP receptors have been identified in various epidermal cell types; therefore, extracellular ATP homeostasis likely determines its long-term, trophic effects on skin health. We investigated the possibility that human keratinocytes express surface-located enzymes that modulate ATP concentration, as well as the corresponding receptor activation, in the pericellular microenvironment. We observed that the human keratinocyte cell line HaCaT released ATP and hydrolyzed extracellular ATP. Interestingly, ATP hydrolysis resulted in adenosine diphosphate (ADP accumulation in the extracellular space. Pharmacological inhibition by ARL 67156 or gene silencing of the endogenous ecto-nucleoside triphosphate diphosphohydrolase (NTPDase isoform 2 resulted in a 25% reduction in both ATP hydrolysis and ADP formation. Using intracellular calcium as a reporter, we found that although NTPDase2 hydrolyzed ATP and generated sustainable ADP levels, only ATP contributed to increased intracellular calcium via P2Y2 receptor activation. Furthermore, knocking down NTPDase2 potentiated the nanomolar ATP-induced intracellular calcium increase, suggesting that NTPDase2 globally attenuates nucleotide concentration in the pericellular microenvironment as well as locally shields receptors in the vicinity from being activated by extracellular ATP. Our findings reveal an important role of human keratinocyte NTPDase2 in modulating nucleotide signaling in the extracellular milieu of human epidermis.

  14. An Effector of Hemoglobin Structure: The Guanosine 3', 5'-Triphosphate

    OpenAIRE

    Rezaei-Zarchi, Saeed; Imani, Saber; Soufian, Safieh; Panahi, Yunes; Saboury, Ali Akbar; Arefi, Mohammad Reza

    2012-01-01

    The effect of guanosine 3', 5'-triphosphate (GTP) on the hemoglobin structure was studied by UV-visible, fluorescence and circular dichroism (CD) spectroscopies, and cyclic voltammetry. UV-visible absorption spectra showed an increase in absorbance in the regions of 420 nm and 280 nm. Fluorescence spectra showed that the Trp fluorescence intensity increased upon excitation at 280 nm, when guanosine 3', 5'-triphosphate concentration was increased in hemoglobin solution. Along with the increase...

  15. Regulation of adenosine levels during cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    Stephanie CHU; Wei XIONG; Dali ZHANG; Hanifi SOYLU; Chao SUN; Benedict C ALBENSI; Fiona E PARKINSON

    2013-01-01

    Adenosine is a neuromodulator with its level increasing up to 100-fold during ischemic events,and attenuates the excitotoxic neuronal injury.Adenosine is produced both intracellularly and extracellularly,and nucleoside transport proteins transfer adenosine across plasma membranes.Adenosine levels and receptor-mediated effects of adenosine are regulated by intracellular ATP consumption,cellular release of ATP,metabolism of extracellular ATP (and other adenine nucleotides),adenosine influx,adenosine efflux and adenosine metabolism.Recent studies have used genetically modified mice to investigate the relative contributions of intra-and extracellular pathways for adenosine formation.The importance of cortical or hippocampal neurons as a source or a sink of adenosine under basal and hypoxic/ischemic conditions was addressed through the use of transgenic mice expressing human equilibrative nucleoside transporter 1 (hENT1) under the control of a promoter for neuron-specific enolase.From these studies,we conclude that ATP consumption within neurons is the primary source of adenosine in neuronal cultures,but not in hippocampal slices or in vivo mice exposed to ischemic conditions.

  16. Five putative nucleoside triphosphate diphosphohydrolase genes are expressed in Trichomonas vaginalis.

    Science.gov (United States)

    Frasson, Amanda Piccoli; Dos Santos, Odelta; Meirelles, Lúcia Collares; Macedo, Alexandre José; Tasca, Tiana

    2016-01-01

    Trichomonas vaginalis is a protozoan that parasitizes the human urogenital tract causing trichomoniasis, the most common non-viral sexually transmitted disease. The parasite has unique genomic characteristics such as a large genome size and expanded gene families. Ectonucleoside triphosphate diphosphohydrolase (E-NTPDase) is an enzyme responsible for hydrolyzing nucleoside tri- and diphosphates and has already been biochemically characterized in T. vaginalis. Considering the important role of this enzyme in the production of extracellular adenosine for parasite uptake, we evaluated the gene expression of five putative NTPDases in T. vaginalis. We showed that all five putative TvNTPDase genes (TvNTPDase1-5) were expressed by both fresh clinical and long-term grown isolates. The amino acid alignment predicted the presence of the five crucial apyrase conserved regions, transmembrane domains, signal peptides, phosphorylation and catalytic sites. Moreover, a phylogenetic analysis showed that TvNTPDase sequences make up a clade with NTPDases intracellularly located. Biochemical NTPDase activity (ATP and ADP hydrolysis) is responsive to the serum-restrictive conditions and the gene expression of TvNTPDases was mostly increased, mainly TvNTPDase2 and TvNTPDase4, although there was not a clear pattern of expression among them. In summary, the present report demonstrates the gene expression patterns of predicted NTPDases in T. vaginalis.

  17. Upregulation of nucleoside triphosphate diphosphohydrolase-1 and ecto-5'-nucleotidase in rat hippocampus after repeated low-dose dexamethasone administration.

    Science.gov (United States)

    Drakulić, Dunja; Stanojlović, Miloš; Nedeljković, Nadežda; Grković, Ivana; Veličković, Nataša; Guševac, Ivana; Mitrović, Nataša; Buzadžić, Ivana; Horvat, Anica

    2015-04-01

    Although dexamethasone (DEX), a synthetic glucocorticoid receptor (GR) analog with profound effects on energy metabolism, immune system, and hypothalamic-pituitary-adrenal axis, is widely used therapeutically, its impact on the brain is poorly understood. The aim of the present study was to explore the effect of repeated low-dose DEX administration on the activity and expression of the ectonucleotidase enzymes which hydrolyze and therefore control extracellular ATP and adenosine concentrations in the synaptic cleft. Ectonucleotidases tested were ectonucleoside triphosphate diphosphohydrolase 1-3 (NTPDase1-3) and ecto-5'-nucleotidase (eN), whereas the effects were evaluated in two brain areas that show different sensitivity to glucocorticoid action, hippocampus, and cerebral cortex. In the hippocampus, but not in cerebral cortex, modest level of neurodegenerative changes as well as increase in ATP, ADP, and AMP hydrolysis and upregulation of NTPDase1 and eN mRNA expression ensued under the influence of DEX. The observed pattern of ectonucleotidase activation, which creates tissue volume with enhanced capacity for adenosine formation, is the hallmark of the response after different insults to the brain.

  18. Adenosine, Energy Metabolism, and Sleep

    Directory of Open Access Journals (Sweden)

    Tarja Porkka-Heiskanen

    2003-01-01

    Full Text Available While the exact function of sleep remains unknown, it is evident that sleep was developed early in phylogenesis and represents an ancient and vital strategy for survival. Several pieces of evidence suggest that the function of sleep is associated with energy metabolism, saving of energy, and replenishment of energy stores. Prolonged wakefulness induces signs of energy depletion in the brain, while experimentally induced, local energy depletion induces increase in sleep, similarly as would a period of prolonged wakefulness. The key molecule in the induction of sleep appears to be adenosine, which induces sleep locally in the basal forebrain.

  19. Actinides and rare earths complexation with adenosine phosphate nucleotides

    International Nuclear Information System (INIS)

    Organophosphorus compounds are important molecules in both nuclear industry and living systems fields. Indeed, several extractants of organophosphorus compounds (such as TBP, HDEHP) are used in the nuclear fuel cycle reprocessing and in the biological field. For instance, the nucleotides are organophosphates which play a very important role in various metabolic processes. Although the literature on the interactions of actinides with inorganic phosphate is abundant, published studies with organophosphate compounds are generally limited to macroscopic and / or physiological approaches. The objective of this thesis is to study the structure of several organophosphorus compounds with actinides to reach a better understanding and develop new specific buildings blocks. The family of the chosen molecules for this procedure consists of three adenine nucleotides mono, bi and triphosphate (AMP, adenosine monophosphate - ADP, adenosine diphosphate - ATP, adenosine triphosphate) and an amino-alkylphosphate (AEP O-phosphoryl-ethanolamine). Complexes synthesis was conducted in aqueous and weakly acidic medium (2.8-4) for several lanthanides (III) (Lu, Yb, Eu) and actinides (U (VI), Th (IV) and Am (III)). Several analytical and spectroscopic techniques have been used to describe the organization of the synthesized complexes: spectrometric analysis performed by FTIR and NMR were used to identify the functional groups involved in the complexation, analysis by ESI-MS and pH-metric titration were used to determine the solution speciation and EXAFS analyzes were performed on Mars beamline of the SOLEIL synchrotron, have described the local cation environment, for both solution and solid compounds. Some theoretical approaches of DFT were conducted to identify stable structures in purpose of completing the experimental studies. All solid complexes (AMP, ADP, ATP and AEP) have polynuclear structures, while soluble ATP complexes are mononuclear. For all synthesized complexes, it has been

  20. Synergistic myoprotection of L-arginine and adenosine in a canine model of global myocardial ischaemic reperfusion injury

    Institute of Scientific and Technical Information of China (English)

    DU Lei; DIAN Ke; CHEN Hui-jiao; AN Qi; JIA Meng-xing; YANG Ping-liang; WANG Wei; DENG Shuo-zeng; LIU Jin

    2007-01-01

    Background Endogenous nitric oxide and adenosine increase simultaneously to keep the balance of energy demand and supply when the oxygen supply is insufficient, which suggests that nitric oxide and adenosine might exert a synergistic myoprotection during tissue hypoxia. In this study, we tested this hypothesis utilizing a canine model of prolonged global myocardial ischaemic reperfusion injury.Methods In this double blind, controlled study, the hearts of 24 anaesthetized mongrel dogs were arrested for 2 hours with aortic cross clamping and blood cardioplegia. The treatment groups were those supplemented with 2 mmol/L L-arginine (ARG), supplemented with 1 mmol/L adenosine (ADO), ARG + ADO supplemented with both, and no supplementation (control) (n=6 in each group). Haemodynamics, biochemical indices, adenosine triphosphate (ATP) content and myeloperoxidase activities of myocardium were determined to evaluate myocardial injury. Statistical comparison was performed by two way ANOVA.Results Although the requirements for inotropic supports were higher, the cardiac outputs were lower in control group than in ARG, ADO and the combination groups. Plasma cardiac troponin I levels were higher and the areas of hydropic changes were larger in control group than in ARG and ADO groups. Combination of arginine and adenosine provided further myoprotection with respect to better cardiac performance, lower release of cardiac troponin I, and smaller areas of hydropic changes compared with ARG and ADO groups. ATP content was higher, but myeloperoxidase activities of myocardium were significantly lower in the combination group than in control, ARG and ADO groups (P<0.05).Conclusions Combination of L-arginine and adenosine provides synergistic myoprotection in a canine model of global myocardial ischaemia. Thus, the combination is recommended when the heart is exposed to a prolonged ischaemia during cardiac surgery.

  1. Running out of time: the decline of channel activity and nucleotide activation in adenosine triphosphate-sensitive K-channels.

    Science.gov (United States)

    Proks, Peter; Puljung, Michael C; Vedovato, Natascia; Sachse, Gregor; Mulvaney, Rachel; Ashcroft, Frances M

    2016-08-01

    KATP channels act as key regulators of electrical excitability by coupling metabolic cues-mainly intracellular adenine nucleotide concentrations-to cellular potassium ion efflux. However, their study has been hindered by their rapid loss of activity in excised membrane patches (rundown), and by a second phenomenon, the decline of activation by Mg-nucleotides (DAMN). Degradation of PI(4,5)P2 and other phosphoinositides is the strongest candidate for the molecular cause of rundown. Broad evidence indicates that most other determinants of rundown (e.g. phosphorylation, intracellular calcium, channel mutations that affect rundown) also act by influencing KATP channel regulation by phosphoinositides. Unfortunately, experimental conditions that reproducibly prevent rundown have remained elusive, necessitating post hoc data compensation. Rundown is clearly distinct from DAMN. While the former is associated with pore-forming Kir6.2 subunits, DAMN is generally a slower process involving the regulatory sulfonylurea receptor (SUR) subunits. We speculate that it arises when SUR subunits enter non-physiological conformational states associated with the loss of SUR nucleotide-binding domain dimerization following prolonged exposure to nucleotide-free conditions. This review presents new information on both rundown and DAMN, summarizes our current understanding of these processes and considers their physiological roles.This article is part of the themed issue 'Evolution brings Ca(2+) and ATP together to control life and death'. PMID:27377720

  2. Rosuvastatin lowers coenzyme Q10 levels, but not mitochondrial adenosine triphosphate synthesis, in children with familial hypercholesterolemia

    NARCIS (Netherlands)

    H.J. Avis; I.P. Hargreaves; J.P.N. Ruiter; J.M. Land; R.J. Wanders; F.A. Wijburg

    2011-01-01

    To investigate whether statin therapy affects coenzyme Q10 (CoQ10) status in children with heterozygous familial hypercholesterolemia (FH). Samples were obtained at baseline (treatment naïve) and after dose titration with rosuvastatin, aiming for a low-density lipoprotein cholesterol level of 110 mg

  3. Comparison of Activities and Properties of Pyrophosphate and Adenosine Triphosphate-Dependent Phosphofructokinases of Black Gram (Phaseolus mungo) Seeds.

    Science.gov (United States)

    Ashihara, H; Stupavska, S

    1984-09-01

    Both pyrophosphate-dependent phosphofructokinase (PPi-PFKase, EC 2.7.1.90) and ATPdependent phosphofructokinase (ATP-PFKase, EC 2.7. 1.11) were present in dry and germinated black gram seeds. In the absence of fructose-2,6-biphosphate (F2,6BP), the activity of PPi-PFKase expressed as nmol · min(-1) · (pair of cotyledons)(-1) was much lower than that of ATP-PFKase in both dry and germinated seeds. However, PPi-PFKase was activated by F2,6BP and its activity reached the same level as ATP-PFKase activity. ATP-PFKase showed sigmoidal kinetics respective to fructose-6-phosphate (F6P), while PPi-PFKase exhibited hyperbolic kinetics in the presence of F2,6BP. The F6P concentration for half maximal activity of ATP-PFKase (1.5 mM) was nearly 5 times lower than that of PPi-PFKase (7.1 mM). The apparent Km values of PPi-PFKase for PPi and that of ATP-PFKase for ATP were 0.29 mM and 0.23 mM, respectively. Phosphoenolpyruvate (PEP) and citrate inhibited ATP-PFKase activity, but they did not affect PPi-PFKase activity. The activity of PPi-PFKase was inhibited by Pi, while only a little Pi inhibition was observed in the case of ATP-PFKase. These results suggest that the control mechanism of PPi-PFKase and that of ATP-PFKase are quite different. In contrast to pineapple leaves (Carnal, N. W. and C. C. Black, Biochem. Biophys. Res. Commun. 86, 20-26, 1979) and caster bean seedlings (Krugar et al., FEBS Lett. 153, 409-412, 1983), PPi-PFKase is not the predominant PFKase activity in black gram seeds.

  4. Adenosine 5'triphosphate transport and accumulation during the cold preservation of rat hepatocytes in University of Wisconsin solution

    Institute of Scientific and Technical Information of China (English)

    María E. Mamprin; Félix Vega; Joaquín V. Rodriguez

    2005-01-01

    AIM: We used isolated hepatocytes to investigate how different concentrations of ATP in the University of Wisconsin (UW) solution affected both cellular ATP content and cell viability during the cold storage and the rewarming step. The mechanism involved in ATP transport and accumulation in hypothermia was also determined.METHODS: The cells were preserved up to 72 h in different conditions: UW solution without ATP (a-group),UW+5 mmol/L ATP (b-group), and UW+10 mmol/L ATP (c-group). The ATP content and the cell viability (LDH release) were determined during the cold storage and the rewarming step. In the groups a and c, the respiratory function of the cells at rewarming was studied. In addition,the cell volume of hepatocytes and the mechanism involved in ATP transport and accumulation were assessed. The extracellular degradation of exogenous nucleotides during transport experiments was investigated by a HPLC technique.RESULTS: After three days of cold storage a loss of cellular ATP content was observed in hepatocytes preserved either without nucleotides (a-group) or with 5 mmol/L ATP (b-group). In contrast, 10 mmol/L ATP (c-group) was able to maintain a normal ATP cellular content, with only a 6% diminution after 72 h of cold storage. The respiratory function was significantly different in hepatocytes preserved with 10 mmol/L ATP than without ATP. No significant change was detected for the three groups in cellular volume during the cold storage. We also report that the time course accumulation of [3H]-ATP by cold stored hepatocytes is a rapid process that is completed after 180 s with linear dependence on the extracellular ATP concentration (linear fitting results in a slope of 0.5624±0.1179 mmol/L ATP intracell/mmol/L ATP extracell).CONCLUSION: Our results show that, during hypothermic storage in UW solution, hepatocytes are permeable to ATP by a diffusive mechanism. Also, we found that it is ATP the main extracellular nucleotide available for transport and it is not the breakdown products.

  5. Potassium and sodium ions in the glycerinated skeletal muscle. Distribution changes induced by adenosine triphosphate and nondissociable anesthetic substances.

    Science.gov (United States)

    Dragomir, C T; Barbier, A; Ungureanu, D; Ionescu, V; Pausescu, E; Chirvasie, R; Ghitescu, D; Filipescu, G

    1975-01-01

    Investigation of the ionic behavior of glycerinated muscle fibers showed that the residual structures of this biologic cellular material, lacking functional membranes, are able to discriminate between alkaline ions. The characteristics of the ionic selectivity of the glycerinated fibers change with their functional state and with the presence in the medium of certain nonionic substances. Among the more important features of ionic distribution between the membrane-free fibers and the medium are the following: (1) There is evident adsorption of potassium on the fibers, in the absence of ATP. (2) This adsorption increases in contraction and decreases in relaxation. (3) At high ionic concentrations, in contrast to what occurs at low potassium concentrations, the glycerinated muscle prefers sodium to potassium, but even under these conditions both ions are accumulated in the fibers to far greater levels than in the medium. This strongly suggests a Donnan ionic equilibrium developing parallel to the adsorption process. (4) Nonionic substances of the general anesthetic group markedly alter the ionic selectivity of the glycerinated fibers, probably by their action on the water's physical state. A mechanism is proposed for the observed ionic adsorption specific of the muscle-a mechanism in which actin-myosin coupling plays the cardinal adsorption role. In the general interpretation of the data a synthetic concept is advanced according to which an entire set of processes and factors concurs with the distribution of ions between the muscle and the medium.

  6. Synthesis and Enzymatic Incorporation of Modified Deoxyuridine Triphosphates

    Directory of Open Access Journals (Sweden)

    Erkai Liu

    2015-07-01

    Full Text Available To expand the chemical functionality of DNAzymes and aptamers, several new modified deoxyuridine triphosphates have been synthesized. An important precursor that enables this aim is 5-aminomethyl dUTP, whereby the pendent amine serves as a handle for further synthetic functionalization. Five functional groups were conjugated to 5-aminomethyl dUTP. Incorporation assays were performed on several templates that demand 2–5 sequential incorporation events using several commercially available DNA polymerases. It was found that Vent (exo- DNA polymerase efficiently incorporates all five modified dUTPs. In addition, all nucleoside triphosphates were capable of supporting a double-stranded exponential PCR amplification. Modified PCR amplicons were PCR amplified into unmodified DNA and sequenced to verify that genetic information was conserved through incorporation, amplification, and reamplification. Overall these modified dUTPs represent new candidate substrates for use in selections using modified nucleotide libraries.

  7. Modified Nucleoside Triphosphates for in-vitro Selection Techniques

    Science.gov (United States)

    Iribarren, Adolfo; Dellafiore, María; Montserrat, Javier

    2016-05-01

    The development of SELEX (Selective Enhancement of Ligands by Exponential Enrichment) provides a powerful tool for the search of functional oligonucleotides with the ability to bind ligands with high affinity and selectivity (aptamers) and for the discovery of nucleic acid sequences with diverse enzymatic activities (ribozymes and DNAzymes). This technique has been extensively applied to the selection of natural DNA or RNA molecules but, in order to improve chemical and structural diversity as well as for particular applications where further chemical or biological stability is necessary, the extension of this strategy to modified oligonucleotides is desirable. Taking into account these needs, this review intends to collect the research carried out during the past years, focusing mainly on the use of modified nucleotides in SELEX and the development of mutant enzymes for broadening nucleoside triphosphates acceptance. In addition, comments regarding the synthesis of modified nucleoside triphosphate will be briefly discussed.

  8. Mast cell adenosine receptors function: a focus on the A3 adenosine receptor and inflammation

    Directory of Open Access Journals (Sweden)

    Noam eRudich

    2012-06-01

    Full Text Available Adenosine is a metabolite, which has long been implicated in a variety of inflammatory processes. Inhaled adenosine provokes bronchoconstriction in asthmatics or chronic obstructive pulmonary disease (COPD patients, but not in non-asthmatics. This hyper responsiveness to adenosine appears to be mediated by mast cell activation. These observations have marked the receptor that mediates the bronchoconstrictor effect of adenosine on mast cells, as an attractive drug candidate. Four subtypes (A1, A2a, A2b and A3 of adenosine receptors have been cloned and shown to display distinct tissue distributions and functions. Animal models have firmly established the ultimate role of the A3 adenosine receptor (A3R in mediating hyper responsiveness to adenosine in mast cells, although the influence of the A2b adenosine receptor was confirmed as well. In contrast, studies of the A3R in humans have been controversial. In this review, we summarize data on the role of different adenosine receptors in mast cell regulation of inflammation and pathology, with a focus on the common and distinct functions of the A3R in rodent and human mast cells. The relevance of mouse studies to the human is discussed.

  9. Electrocardiographic profile of adenosine pharmacological stress testing

    OpenAIRE

    Sun, Hao; TIAN, YUEQIN; ZHENG, LIHUI; Pan, Qingrong; XIE, BOQIA

    2015-01-01

    Adenosine stress testing in conjunction with radionuclide myocardial perfusion imaging has become a common approach for the detection of coronary artery diseases in patients who are unable to perform adequate levels of exercise. However, specific electrocardiographic alterations during the test have been rarely described. Using a Chinese population, the aim of the present study was to provide a detailed electrocardiographic profile of adenosine stress testing. The study population included 1,...

  10. Polyadenylation inhibition by the triphosphates of deoxyadenosine analogues

    OpenAIRE

    Chen, Lisa S.; Plunkett, William; Gandhi, Varsha

    2008-01-01

    The nucleotide substrate specificity of yeast poly(A) polymerase (yPAP) was examined with various ATP analogues of clinical relevance. The triphosphate derivatives of cladribine (2-Cl-dATP), clofarabine (Cl-F-ara-ATP), fludarabine (F-ara-ATP), and related derivatives were incubated with yPAP and 32P-radiolabeled RNA oligonucleotide primers in the absence of ATP to assay polyadenylation. While 2-Cl-ATP resulted in primer elongation, ara-ATP and F-ara-ATP were poor substrates for yPAP. In contr...

  11. Adenosine modulation of [Ca2+]i in cerebellar granular cells: multiple adenosine receptors involved.

    Science.gov (United States)

    Vacas, Javier; Fernández, Mercedes; Ros, Manuel; Blanco, Pablo

    2003-12-01

    Elimination of adenosine by addition of adenosine deaminase (ADA) to the media leads to alterations in intracellular free calcium concentration ([Ca(2+)](i)) in cerebellar granular cells. Adenosine deaminase brings about increases or decreases in [Ca(2+)](i) depending on the previous activation state of the cell. These effects are dependent on the catalytic activity of adenosine deaminase, since its previous catalytic inactivation with Hg(2+) prevents the above-mentioned changes in intracellular calcium. Extracellular calcium is required for the increase in [Ca(2+)](i) promoted by ADA. This rise is insensitive to thapsigargin, but sensitive to micromolar concentrations of Ni(2+). Toxins specific for L, N and P/Q calcium channels do not overtly reduce this effect. N(6)-Cyclopentyl adenosine (CPA), an A(1) receptor agonist, produces a partial reversion of ADA effects, while CGS21680, A(2A)/A(2B) receptor agonist, slightly enhances them. Expression of A(1), A(2A), A(2B) and A(3) adenosine receptor mRNAs was detected in cerebellar granular cell cultures. These results suggest that adenosine modulate [Ca(2+)](i) in cerebellar granule cells through different adenosine receptor subtypes which, at least in part, seem to act through R-type calcium channels.

  12. Adenosine stress protocols for myocardial perfusion imaging

    Directory of Open Access Journals (Sweden)

    Baškot Branislav

    2008-01-01

    Full Text Available Background/Aim. Treadmill test combined with myocardial perfusion scintigraphy (MPS is a commonly used technique in the assessment of coronary artery disease. There are many patients, however, who may not be able to undergo treadmill test. Such patients would benefit from pharmacological stress procedures combined with MPS. The most commonly used pharmacological agents for cardiac stress are coronary vasodilatators (adenosine, dipyridamol and catecholamines. Concomitant low-level treadmill exercise with adenosine pharmacologic stress (AdenoEX during MPS has become commonly used in recent years. A number of studies have demonstrated a beneficial impact of AdenoEX protocol. The aim of the study was, besides introducing into practice the two types of protocols of pharmatological stress test with adenosine, as a preparation for MPS, to compare and monitor the frequency of their side effects to quality, acquisition, as well as to standardize the onset time of acquisition (diagnostic imaging for both protocols. Methods. A total of 130 patients underwent pharmacological stress test with adenosine (vasodilatator. In 108 of the patients we performed concomitant exercise (AdenoEX of low level (50W by a bicycle ergometar. In 28 of the patients we performed Adenosine abbreviated protocol (AdenoSCAN. Side effects of adenosine were followed and compared between the two kinds of protocols AdenoEX and AdenoSCAN. Also compared were image quality and suggested time of acquisition after the stress test. Results. Numerous side effects were found, but being short-lived they did not require any active interventions. The benefit of AdenoEX versus AdenoSCAN included decreased side effects (62% vs 87%, improved safety and patients tolerance, improved target-to-background ratios because of less subdiaphragmatic activity, earlier acquisition, and improved sensitivity. Conclusion. The safety and efficacy of adenosine pharmacological stress is even better with concomitant

  13. Growth inhibitory effect and apoptosis induced by extracellular ATP and adenosine on human gastric carcinoma cells: involvement of intracellular uptake of adenosine

    Institute of Scientific and Technical Information of China (English)

    Ming-xia WANG; Lei-ming REN

    2006-01-01

    Aim: To study the growth inhibitory and apoptotic effects of adenosine triphosphate (ATP) and adenosine (ADO) on human gastric carcinoma (HGC)-27 cells in vitro and the mechanisms related to the actions of ATP and ADO. Methods: MTT assay was used to determine the reduction of cell viability. The morphological changes of HGC-27 cells induced by ATP or ADO were observed under fluorescence light microscope by acridine orange/ethidium bromide double-stained cells. The internucleosomal fragmentation of genomic DNA was detected by agarose gel electrophoresis. The apoptotic rate and cell-cycle analysis after treatment with ATP or ADO was determined by flow cytometry. Results: ATP, ADO and the intermediate metabolites, ADP and AMP, and the agonist of purinergic receptors, reduced cell viability of HGC-27 cells at doses of 0.3 and 1.0 mmol·L-1. The distribution of cell cycle phase and proliferation index (PI) value of HGC-27 cells changed when exposed to ATP or ADO at the concentrations of 0.1,0.3 and 1 mmol/L for 48 h. ATP and ADO both altered the distribution of cell cycle phase via Go/G1-phase arrest and significantly decreased PI value. Under light microscope, the tumor cells exposed to 0.3 mmol·L-1 ATP or ADO displayed morphological changes of apoptosis; a ladder-like pattern of DNA fragmentation obtained from HGC-27 cells treated with 0.1-1 mmol·L-1 ATP or ADO appeared in agarose gel electrophoresis; ATP and ADO induced the apoptosis of HGC-27 cells in a dose-dependent manner at concentrations between 0.03-1 mmol·L-1. The maximum apoptotic rate of HGC-27 cells exposed to ATP or ADO for 48 h was 13.53% or 15.9%, respectively. HGC-27 cell death induced by ATP or ADO was significantly inhibited by dipy-ridamole (10 mmol·L-1), an inhibitor of adenosine transporter, but was not affected by aminophylline, a broad inhibitor of PI receptors and pyridoxal-phosphate-6-azophenyl-2, 4-disulphonic acid tetrasodium salt (30 nmol·L-1), a non-selective antagonist of P2

  14. Determination of adenosine effects and adenosine receptors in murine corpus cavernosum.

    Science.gov (United States)

    Tostes, Rita C; Giachini, Fernanda R C; Carneiro, Fernando S; Leite, Romulo; Inscho, Edward W; Webb, R Clinton

    2007-08-01

    This study tested the hypothesis that adenosine, in murine corpora cavernosa, produces direct relaxation of smooth muscle cells and inhibition of contractile responses mediated by sympathetic nerve stimulation. Penes were excised from anesthetized male C57BL/6 mice, dissected, and cavernosal strips were mounted to record isometric force. Adenosine, 2-chloroadenosine (stable analog of adenosine), and 2-phenylaminoadenosine (CV1808) (A2(A)/A2(B) agonist) produced concentration-dependent relaxations of phenylephrine-contracted tissues. Relaxation to 2-chloroadenosine was inhibited, in a concentration-dependent manner, by 2-(2-furanyl)-7-(2-phenylethyl)-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine (SCH58261; A2(A) antagonist; 10(-9)-10(-6) M) and N-(4-acetylphenyl)-2-[4-(2,3,6,7-tetrahydro-2,6-dioxo-1,3-dipropyl-1H-purin-8-yl)phenoxy]acetamida (MRS1706; A2(B) antagonist; 10(-8)-10(-6) M). The combination of both antagonists abrogated 2-chloroadenosine-induced relaxation. Electrical field stimulation (EFS; 1-32 Hz) of adrenergic nerves produced frequency-dependent contractions that were inhibited by compounds that increase adenosine levels, such as 5'-iodotubercidin (adenosine kinase inhibitor), erythro-9-(2-hydroxy-3-nonyl)adenine (adenosine deaminase inhibitor), and dipyridamole (inhibitor of adenosine transport). The adenosine A1 receptor agonist N(6)-cyclopentyladenosine (C8031) right-shifted contractile responses to EFS, with a significant inhibitory effect at 10(-6) M. Blockade of adenosine A1 receptors with 8-cyclopentyl-1,3-dipropylxanthine (C101) (10(-7) M) enhanced contractile responses to EFS and eliminated the inhibitory effects of 5'-iodotubercidin. Dipyridamole and 5'-iodotubercidin had no effect on adenosine-mediated relaxation. In summary, adenosine directly relaxes cavernosal smooth muscle cells, by the activation of A2(A)/A2(B) receptor subtypes. In addition, adenosine negatively modulates sympathetic neurotransmission, by A1 receptor

  15. Internalization and desensitization of adenosine receptors.

    NARCIS (Netherlands)

    Klaasse, E.C.; IJzerman, A.P.; Grip, W.J. de; Beukers, M.W.

    2008-01-01

    Until now, more than 800 distinct G protein-coupled receptors (GPCRs) have been identified in the human genome. The four subtypes of the adenosine receptor (A(1), A(2A), A(2B) and A(3) receptor) belong to this large family of GPCRs that represent the most widely targeted pharmacological protein clas

  16. WBC27, an Adenosine Tri-phosphate-binding Cassette Protein, Controls Pollen Wall Formation and Patterning in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Xiao-Ying Dou; Ke-Zhen Yang; Yi Zhang; Wei Wang; Xiao-Lei Liu; Li-Qun Chen; Xue-Qin Zhang; De Ye

    2011-01-01

    In flowering plants, the exine components are derived from tapetum. Despite its importance to sexual plant reproduction, little is known about the translocation of exine materials from tapetum to developing microspores. Here we report functional characterization of the arabidopsis WBC27 gene. WBC27 encodes an adenosine tri-phosphate binding cassette (ABC) transporter and is expressed preferentially in tapetum. Mutation of WBC27 disrupted the exine formation. The wbc27 mutant microspores began to degenerate once released from tetrads and most of the microspores collapsed at the uninucleate stage. Only a small number of wbc27-1 microspores could develop into tricellular pollen grains. These survival pollen grains lacked exine and germinated in the anther before anthesis. All of these results suggest that the ABC transporter, WBC27 plays important roles in the formation of arabidopsis exine, possibly by translocation of lipidic precursors of sporopollenin from tapetum to developing microspores.

  17. Adenosine: An immune modulator of inflammatory bowel diseases

    Institute of Scientific and Technical Information of China (English)

    Jeff Huaqing Ye; Vazhaikkurichi M Rajendran

    2009-01-01

    Inflammatory bowel disease (IBD) is a common and lifelong disabling gastrointestinal disease. Emerging treatments are being developed to target inflammatory cytokines which initiate and perpetuate the immune response. Adenosine is an important modulator of inflammation and its anti-inflammatory effects have been well established in humans as well as in animal models. High extracellular adenosine suppresses and resolves chronic inflammation in IBD models. High extracellular adenosine levels could be achieved by enhanced adenosine absorption and increased de novo synthesis. Increased adenosine concentration leads to activation of the A2a receptor on the cell surface of immune and epithelial cells that would be a potential therapeutic target for chronic intestinal inflammation. Adenosine is transported via concentrative nucleoside transporter and equilibrative nucleoside transporter transporters that are localized in apical and basolateral membranes of intestinal epithelial cells, respectively. Increased extracellular adenosine levels activate the A2a receptor, which would reduce cytokines responsible for chronic inflammation.

  18. Adenosine receptors and asthma in humans

    OpenAIRE

    Wilson, C N

    2008-01-01

    According to an executive summary of the GINA dissemination committee report, it is now estimated that approximately 300 million people (5% of the global population or 1 in 20 persons) have asthma. Despite the scientific progress made over the past several decades toward improving our understanding of the pathophysiology of asthma, there is still a great need for improved therapies, particularly oral therapies that enhance patient compliance and that target new mechanisms of action. Adenosine...

  19. Aminopyrimidine derivatives as adenosine antagonists / Janke Kleynhans

    OpenAIRE

    Kleynhans, Janke

    2013-01-01

    Aims of this project - The aim of this study was to design and synthesise novel 2-aminopyrimidine derivatives as potential adenosine A1 and A2A receptor antagonists. Background and rationale - Parkinson’s disease is the second most common neurodegenerative disorder (after Alzheimer’s disease) and is characterised by the selective death of the dopaminergic neurons of the nigro-striatal pathway. Distinctive motor symptoms include bradykinesia, muscle rigidity and tremor, while non-m...

  20. Association of Thymidylate Synthase Gene Polymorphisms with Stavudine Triphosphate Intracellular Levels and Lipodystrophy▿

    OpenAIRE

    Domingo, Pere (Domingo Pedrol); Cabeza, M. Carmen; Pruvost, Alain; Torres, Ferran; Salazar, Juliana; del Mar Gutierrez, M.; Mateo, M. Gracia; Fontanet, Angels; Fernandez, Irene; Domingo, Joan C.; Villarroya, Francesc; Vidal, Francesc; Baiget, Montserrat

    2011-01-01

    The antiviral activity and toxicity of stavudine (d4T) depend on its triphosphate metabolite, stavudine triphosphate (d4T-TP). Therefore, modifications in intracellular levels of d4T-TP may change the toxicity profile of stavudine. d4T-TP intracellular levels in peripheral blood mononuclear cells were determined with a prominence liquid chromatograph connected to a triple-quadruple mass spectrometer. Polymorphisms in the thymidylate synthase (TS), methylenetetrahydrofolate reductase (MTHFR), ...

  1. [The involvement of adenosine and adenosine deaminase in experimental myocardial infarct].

    Science.gov (United States)

    Stratone, A; Busuioc, A; Roşca, V; Bazgan, L; Popa, M; Hăulică, I

    1989-01-01

    By the ligature of the left coronary artery in the rat anesthetized with nembutal (10 mg/100 i.p.) a significant increase of the 5'-nucleotidase activity (Wooton method) was noticed 10 minutes after the left ventricle infarction (from an average value of 1038.5 +/- 187 mU/g tissue to 1537 +/- 225 mU/g fresh tissue). The adenosine desaminase levels spectrophotometrically determined by Denstedt technique, do not appear significantly modified 10 or 30 minutes after the left ventricle infarction. The chromatographically determined adenosine levels, by HPLC technique, decrease from the average value of 11.63 +/- 1.4 micrograms/mg PT to 8.60 +/- 1.0 micrograms/mg PT 30 minutes after infarction. The observed changes are explained by the conditions of hypoxia in the infarcted ventricle which lead to the raise in adenosine levels by activating the 5'-nucleotidase and their depression by a very fast metabolism of the same substance.

  2. Transcriptional activation of the nitrogenase promoter in vitro: adenosine nucleotides are required for inhibition of NIFA activity by NIFL.

    Science.gov (United States)

    Eydmann, T; Söderbäck, E; Jones, T; Hill, S; Austin, S; Dixon, R

    1995-03-01

    The enhancer-binding protein NIFA is required for transcriptional activation of nif promoters by the alternative holoenzyme form of RNA polymerase, which contains the sigma factor sigma 54 (sigma N). NIFA hydrolyzes nucleoside triphosphates to catalyze the isomerization of closed promoter complexes to transcriptionally competent open complexes. The activity of NIFA is antagonized by the regulatory protein NIFL in response to oxygen and fixed nitrogen in vivo. We have investigated the requirement for nucleotides in the formation and stability of open promoter complexes by NIFA and inhibition of its activity by NIFL at the Klebsiella pneumoniae nifH promoter. Open complexes formed by sigma 54-containing RNA polymerase are considerably more stable to heparin challenge in the presence of GTP than in the presence of ATP. This differential stability is most probably a consequence of GTP being the initiating nucleotide at this promoter. Adenosine nucleosides are specifically required for Azotobacter vinelandii NIFL to inhibit open complex formation by native NIFA, and the nucleoside triphosphatase activity of NIFA is strongly inhibited by NIFL under these conditions. We propose a model in which NIFL modulates the activity of NIFA via an adenosine nucleotide switch. PMID:7868590

  3. N6-(2-Hydroxyethyl)-Adenosine Exhibits Insecticidal Activity against Plutella xylostella via Adenosine Receptors

    Science.gov (United States)

    Fang, Ming; Chai, Yiqiu; Chen, Guanjv; Wang, Huidong; Huang, Bo

    2016-01-01

    The diamondback moth, Plutella xylostella, is one of the most important pests of cruciferous crops. We have earlier shown that N6-(2-hydroxyethyl)-adenosine (HEA) exhibits insecticidal activity against P. xylostella. In the present study we investigated the possible mechanism of insecticidal action of HEA on P. xylostella. HEA is a derivative of adenosine, therefore, we speculated whether it acts via P. xylostella adenosine receptor (PxAdoR). We used RNAi approach to silence PxAdoR gene and used antagonist of denosine receptor (AdoR) to study the insecticidal effect of HEA. We cloned the whole sequence of PxAdoR gene. A BLAST search using NCBI protein database showed a 61% identity with the Drosophila adenosine receptor (DmAdoR) and a 32–35% identity with human AdoR. Though the amino acids sequence of PxAdoR was different compared to other adenosine receptors, most of the amino acids that are known to be important for adenosine receptor ligand binding and signaling were present. However, only 30% binding sites key residues was similar between PxAdoR and A1R. HEA, at a dose of 1 mg/mL, was found to be lethal to the second-instar larvae of P. xylostella, and a significant reduction of mortality and growth inhibition ratio were obtained when HEA was administered to the larvae along with PxAdoR-dsRNA or antagonist of AdoR (SCH58261) for 36, 48, or 60 h. Especially at 48 h, the rate of growth inhibition of the PxAdoR knockdown group was 3.5-fold less than that of the HEA group, and the corrected mortality of SCH58261 group was reduced almost 2-fold compared with the HEA group. Our findings show that HEA may exert its insecticidal activity against P. xylostella larvae via acting on PxAdoR. PMID:27668428

  4. Effects of adenosine agonist R-phenylisopropyl-adenosine on halothane anesthesia and antinociception in rats

    Institute of Scientific and Technical Information of China (English)

    Hai-chun MA; Yan-fen WANG; Chun-sheng FENG; Hua ZHAO; Shuji DOHI

    2005-01-01

    Aim: To investigate the antinociceptive effect of adenosine agonist Rphenylisopropyl-adenosine (R-PIA) given to conscious rats by intracerebroventricular (ICV) and intrathecal (IT), and identify the effect of R-PIA on minimum alveolar concentration (MAC) of halothane with pretreatment of A1 receptor an tagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) or K+ channel blocker 4-aminopyridine (4-AP). Methods: Sprague-Dawley rats were implanted with 24 gauge stainless steel guide cannula using stereotaxic apparatus and ICV method, and an IT catheter (PE-10, 8.5 cm) was inserted into the lumbar subarachnoid space, while the rats were under pentobarbital anesthesia. After one week of recovery from surgery, rats were randomly assigned to one of the following protocols: MAC of halothane, or tail-flick latency. All measurements were performed after R-PIA (0.8-2.0 μg) microinjection into ICV and IT with or without pretreatment of DPCPX or 4-AP. Results: Microinjection of adenosine agonist R PIA in doses of 0.8-2.0 μg into ICV and IT produced a significant dose- and time dependent antinociceptive action as reflected by increasing latency times and ICV administration of adenosine agonist R-PIA (0.8 μg) reducing halothane anes thetic requirements (by 29%). The antinociception and reducing halothane requirements effected by adenosine agonist R-PIA was abolished by DPCPX and 4-AP. Conclusion: ICV and IT administration of adenosine agonist R-PIA produced an antinociceptive effect in a dose-dependent manner and decreased hal othane MAC with painful stimulation through activation of A1 receptor subtype, and the underlying mechanism involves K+ channel activation.

  5. A metabolic immune checkpoint: adenosine in tumor microenvironment

    Directory of Open Access Journals (Sweden)

    Akio eOhta

    2016-03-01

    Full Text Available Within tumors, some areas are less oxygenated than others. Since their home ground is under chronic hypoxia, tumor cells adapt to this condition by activating aerobic glycolysis; however, this hypoxic environment is very harsh for incoming immune cells. Deprivation of oxygen limits availability of energy sources and induces accumulation of extracellular adenosine in tumors. Extracellular adenosine, upon binding with adenosine receptors on the surface of various immune cells, suppresses pro-inflammatory activities. In addition, signaling through adenosine receptors upregulates a number of anti-inflammatory molecules and immunoregulatory cells, leading to the establishment of a long-lasting immunosuppressive environment. Thus, due to hypoxia and adenosine, tumors can discourage anti-tumor immune responses no matter how the response was induced, whether it was spontaneous or artificially introduced with a therapeutic intention. Preclinical studies have shown the significance of adenosine in tumor survival strategy by demonstrating tumor regression after inactivation of adenosine receptors, inhibition of adenosine-producing enzymes or reversal of tissue hypoxia. These promising results indicate a potential use of the inhibitors of the hypoxia-adenosine pathway for cancer immunotherapy.

  6. Pretreatment with adenosine and adenosine A1 receptor agonist protects against intestinal ischemia-reperfusion injury in rat

    Institute of Scientific and Technical Information of China (English)

    V Haktan Ozacmak; Hale Sayan

    2007-01-01

    AIM: To examine the effects of adenosine and A1 receptor activation on reperfusion-induced small intestinal injury.METHODS: Rats were randomized into groups with sham operation, ischemia and reperfusion, and systemic treatments with either adenosine or 2-chloro-N6-cyclopentyladenosine, A1 receptor agonist or 8-cyclopentyl-1,3-dipropylxanthine, A1 receptor antagonist, plus adenosine before ischemia. Following reperfusion, contractions of ileum segments in response to KCl, carbachol and substance P were recorded. Tissue myeloperoxidase,malondialdehyde, and reduced glutathione levels were measured.RESULTS: Ischemia significantly decreased both contraction and reduced glutathione level which were ameliorated by adenosine and agonist administration. Treatment also decreased neutrophil infiltration and membrane lipid peroxidation. Beneficial effects of adenosine were abolished by pretreatment with A1 receptor antagonist.CONCLUSION: The data suggest that adenosine and A1 receptor stimulation attenuate ischemic intestinal injury via decreasing oxidative stress, lowering neutrophil infiltration, and increasing reduced glutathione content.

  7. Mechanism of protection of adenosine from sulphate radical anion and repair of adenosine radicals by caffeic acid in aqueous solution

    Indian Academy of Sciences (India)

    M Sudha Swaraga; L Charitha; M Adinarayana

    2005-07-01

    The photooxidation of adenosine in presence of peroxydisulphate (PDS) has been studied by spectrophotometrically measuring the absorbance of adenosine at 260 nm. The rates of oxidation of adenosine by sulphate radical anion have been determined in the presence of different concentrations of caffeic acid. Increase in [caffeic acid] is found to decrease the rate of oxidation of adenosine suggesting that caffeic acid acts as an efficient scavenger of $SO_{4}^{\\bullet-}$ and protects adenosine from it. Sulphate radical anion competes for adenosine as well as for caffeic acid. The quantum yields of photooxidation of adenosine have been calculated from the rates of oxidation of adenosine and the light intensity absorbed by PDS at 254 nm, the wavelength at which PDS is activated to sulphate radical anion. From the results of experimentally determined quantum yields (exptl) and the quantum yields calculated (cal) assuming caffeic acid acting only as a scavenger of $SO_{4}^{\\bullet-}$ show that exptl values are lower than cal values. The ' values, which are experimentally found quantum yield values at each caffeic acid concentration and corrected for $SO_{4}^{\\bullet-}$ scavenging by caffeic acid, are also found to be greater than exptl values. These observations suggest that the transient adenosine radicals are repaired by caffeic acid in addition to scavenging of sulphate radical anions.

  8. High-dose adenosine overcomes the attenuation of myocardial perfusion reserve caused by caffeine.

    OpenAIRE

    Reyes, E.; Loong, C Y; Harbinson, Mark; Donovan, J; Anagnostopoulos, C.; Underwood, S. R.

    2008-01-01

    Objectives:We studied whether an increase in adenosine dose overcomes caffeine antagonism on adenosine-mediated coronary vasodilation.Background:Caffeine is a competitive antagonist at the adenosine receptors, but it is unclear whether caffeine in coffee alters the actions of exogenous adenosine, and whether the antagonism can be surmounted by increasing the adenosine dose.Methods:Myocardial perfusion scintigraphy (MPS) was used to assess adenosine-induced hyperemia in 30 patients before (bas...

  9. Effect of calcium triphosphate cement on proximal humeral fracture osteosynthesis: a finite element analysis.

    Science.gov (United States)

    Kennedy, Jim; Feerick, Emer; McGarry, Patrick; FitzPatrick, David; Mullett, Hannan

    2013-08-01

    PURPOSE. To measure the effect of void-filling calcium triphosphate cement on the loads at the implant-bone interface of a proximal humeral fracture osteosynthesis using a finite element analysis. METHODS. Finite element models of a 3-part proximal humeral fracture fixed with a plate with and without calcium triphosphate cement augmentation were generated from a quantitative computed tomography dataset of an intact proximal humerus. Material properties were assigned to bone fragments using published expressions relating Young's modulus to local Hounsfield number. Boundary conditions were then applied to the model to replicate the physiological loads. The effect of void-filling calcium triphosphate cement was analysed. RESULTS. When the void was filled with calcium triphosphate cement, the pressure gradient of the bone surrounding the screws in the medial fracture fragment decreased 97% from up to 21.41 to 0.66 MPa. Peak pressure of the fracture planes decreased 95% from 6.10 to 0.30 MPa and occurred along the medial aspect. The mean stress in the screw locking mechanisms decreased 78% from 71.23 to 15.92 MPa. The angled proximal metaphyseal screw had the highest stress. CONCLUSION. Augmentation with calcium triphosphate cement improves initial stability and reduces stress on the implant-bone interface. PMID:24014777

  10. Comorbidities in Neurology: Is Adenosine the Common Link?

    Science.gov (United States)

    Boison, Detlev; Aronica, Eleonora

    2015-01-01

    Comorbidities in Neurology represent a major conceptual and therapeutic challenge. For example, temporal lobe epilepsy (TLE) is a syndrome comprised of epileptic seizures and comorbid symptoms including memory and psychiatric impairment, depression, and sleep dysfunction. Similarly, Alzheimer’s disease (AD), Parkinson’s disease (PD), and Amyotrophic Lateral Sclerosis (ALS) are accompanied by various degrees of memory dysfunction. Patients with AD have an increased likelihood for seizures, whereas all four conditions share certain aspects of psychosis, depression, and sleep dysfunction. This remarkable overlap suggests common pathophysiological mechanisms, which include synaptic dysfunction and synaptotoxicity, as well as glial activation and astrogliosis. Astrogliosis is linked to synapse function via the tripartite synapse, but astrocytes also control the availability of gliotransmitters and adenosine. Here we will specifically focus on the ‘adenosine hypothesis of comorbidities’ implying that astrocyte activation, via overexpression of adenosine kinase (ADK), induces a deficiency in the homeostatic tone of adenosine. We present evidence from patient-derived samples showing astrogliosis and overexpression of ADK as common pathological hallmark of epilepsy, AD, PD, and ALS. We discuss a transgenic ‘comorbidity model’, in which brain-wide overexpression of ADK and resulting adenosine deficiency produces a comorbid spectrum of seizures, altered dopaminergic function, attentional impairment, and deficits in cognitive domains and sleep regulation. We conclude that dysfunction of adenosine signaling is common in neurological conditions, that adenosine dysfunction can explain comorbid phenotypes, and that therapeutic adenosine augmentation might be effective for the treatment of comorbid symptoms in multiple neurological conditions. PMID:25979489

  11. Changes in phosphorylation of adenosine phosphate and redox state of nicotinamide-adenine dinucleotide (phosphate) in Geobacter sulfurreducens in response to electron acceptor and anode potential variation

    KAUST Repository

    Rose, Nicholas D.

    2015-12-01

    © 2015 Elsevier B.V. Geobacter sulfurreducens is one of the dominant bacterial species found in biofilms growing on anodes in bioelectrochemical systems. The intracellular concentrations of reduced and oxidized forms of nicotinamide-adenine dinucleotide (NADH and NAD+, respectively) and nicotinamide-adenine dinucleotide phosphate (NADPH and NADP+, respectively) as well as adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP) were measured in G. sulfurreducens using fumarate, Fe(III)-citrate, or anodes poised at different potentials (110, 10, -90, and -190mV (vs. SHE)) as the electron acceptor. The ratios of CNADH/CNAD+ (0.088±0.022) and CNADPH/CNADP+ (0.268±0.098) were similar under all anode potentials tested and with Fe(III)-citrate (reduced extracellularly). Both ratios significantly increased with fumarate as the electron acceptor (0.331±0.094 for NAD and 1.96±0.37 for NADP). The adenylate energy charge (the fraction of phosphorylation in intracellular adenosine phosphates) was maintained near 0.47 under almost all conditions. Anode-growing biofilms demonstrated a significantly higher molar ratio of ATP/ADP relative to suspended cultures grown on fumarate or Fe(III)-citrate. These results provide evidence that the cellular location of reduction and not the redox potential of the electron acceptor controls the intracellular redox potential in G. sulfurreducens and that biofilm growth alters adenylate phosphorylation.

  12. 微波-超声波辅助合成聚乙烯亚胺包覆Mn掺杂ZnS量子点用于室温磷光检测三磷酸鸟苷%Microwave and Ultrasonic-assisted Synthesis of PEI-capped Mn-doped ZnS QDs for Room Temperature Phosphorescence Detection of Guanosine 5'-triphosphate

    Institute of Scientific and Technical Information of China (English)

    任呼博; 杨成雄; 严秀平

    2012-01-01

    High quality PEI-capped Mn-doped ZnS QDs were prepared via a microwave and ultrasonic-assisted synthesis for room temperature phosphorescence detection of guanosine 5 ' -triphosphate ( GTP). Such QDs showed high selectivity and sensitivity for GTP, and could distinguish GTP from adenosine triphosphate ( ATP ) , cytidine triphosphate ( CTP ) , uridine triphosphate ( UTP) , adeno-sine diphosphate ( ADP) and adenosine monophosphate ( AMP ) . The room temperature phosphorescence response of the PEI-capped Mn-doped ZnS QDs for GTP reached equilibrium in 3 min. PEI-capped Mn-doped ZnS QDs gave a detection limit(3s) of 0. 6 (xmol/L for GTP. The developed phosphorescence probe favors biological applications since the interference from scattering light and au-tofluorescence can be effectively eliminated. The developed method has been successfully applied for the room temperature phosphorescence detection of GTP in cancer cell extract.%利用微波-超声波辅助方法合成了水溶性聚乙烯亚胺包覆Mn掺杂ZnS量子点,并建立了基于该量子点的室温磷光检测三磷酸鸟苷(GTP)的新方法.该量子点对GTP具有较高的灵敏度和选择性,能区分GTP与其结构类似物三磷酸腺苷(ATP)、三磷酸胞苷(CTP)、三磷酸尿苷(UTP)、二磷酸腺苷(ADP)和一磷酸腺苷(AMP).该量子点的室温磷光对GTP的响应在3 min内达到平衡,其磷光增强值与GTP浓度呈良好的线性关系,对GTP的检出限为0.6μmol/L.该方法成功应用于癌细胞提取液中GTP的检测,为GTP的检测提供了新方法.

  13. The role of adenosine receptors and endogenous adenosine in citalopram-induced cardiovascular toxicity

    OpenAIRE

    Kubilay Oransay; Nil Hocaoglu; Mujgan Buyukdeligoz; Yesim Tuncok; Sule Kalkan

    2014-01-01

    Aim: We investigated the role of adenosine in citalopram-induced cardiotoxicity. Materials and Methods: Protocol 1: Rats were randomized into four groups. Sodium cromoglycate was administered to rats. Citalopram was infused after the 5% dextrose, 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX; A 1 receptor antagonist), 8-(-3-chlorostyryl)-caffeine (CSC; A 2a receptor antagonist), or dimethyl sulfoxide (DMSO) administrations. Protocol 2: First group received 5% dextrose intraperitoneally 1 hour...

  14. Further observations on the utilization of adenosine triphosphate in rat mast cells during histamine release induced by the ionophore A23187

    DEFF Research Database (Denmark)

    Johansen, Torben

    1980-01-01

    1 The relation between A23187-induced histamine release and the energy metabolism of the rat mast cells has been studied. 2 Ethacrynic acid was used as an inhibitor of calcium-induced histamine release from mast cells primed with the ionophore A23187, and to study calcium-induced changes in the a......1 The relation between A23187-induced histamine release and the energy metabolism of the rat mast cells has been studied. 2 Ethacrynic acid was used as an inhibitor of calcium-induced histamine release from mast cells primed with the ionophore A23187, and to study calcium-induced changes...... demand of energy for exocytosis was estimated to be equivalent to 0.14 pmol of ATP pr 10(3) mast cells....

  15. The accuracy and side effects of pharmacologic stress thallium myocardial scintigraphy with adenosine triphosphate disodium (ATP) infusion in the diagnosis of coronary artery disease

    International Nuclear Information System (INIS)

    The diagnostic accuracy and side effects of pharmacologic stress thallium myocardial scintigraphy with ATP infusion were studied in 172 patients with or without coronary artery disease. ATP was infused for five minutes at a rate of 0.16 mg/kg/min (group A) or 0.18 mg/kg/min (group B) via antecubital vein. One hundred and eleven (67 of group A, 44 of group B) of 172 patients underwent coronary arteriography (CAG). In 111 patients received CAG, overall sensitivity, specificity and accuracy of this method were 88%, 84% and 87%, respectively. In 67 patients of group A, these were 92%, 81% and 90%. In 44 patients of group B, 79%, 87% and 82% were documented (NS, between groups A and B). Chest pain, flushing, bradycardia and ST depression were included in side effects caused by ATP infusion. At least one of these side effects were observed in 84% of the all 172 patients, 89% of group A and 75% of group B (NS). But, all of the side effects were spontaneously alleviated within two minutes without any therapy. In conclusion, pharmacologic stress myocardial scintigraphy with ATP infusion is very accurate and safe, and infusion rate of 0.16 mg/kg/min is optimal for this purpose. (author)

  16. Construction of deletion mutants in the phosphotransferase transport system and adenosine triphosphate-binding cassette transporters in Listeria monocytogenes and analysis of their growth under different stress conditions

    OpenAIRE

    Marina Ceruso; Pina Fratamico; Claudia Chirollo; Rosanna Taglialatela; Maria Luisa Cortesi; Tiziana Pepe

    2013-01-01

    Functional genomics approaches enable us to investigate the biochemical, cellular, and physiological properties of each gene product and are nowadays applied to enhance food safety by understanding microbial stress responses in food and host-pathogen interactions. Listeria monocytogenes is a food-borne pathogen that causes listeriosis and is difficult to eliminate this pathogen since it can survive under multiple stress conditions such as low pH and low temperature. Detailed studies are neede...

  17. Conservation of Complete Trimethylation of Lysine-43 in the Rotor Ring of c-Subunits of Metazoan Adenosine Triphosphate (ATP) Synthases*

    Science.gov (United States)

    Walpole, Thomas B.; Palmer, David N.; Jiang, Huibing; Ding, Shujing; Fearnley, Ian M.; Walker, John E.

    2015-01-01

    The rotors of ATP synthases turn about 100 times every second. One essential component of the rotor is a ring of hydrophobic c-subunits in the membrane domain of the enzyme. The rotation of these c-rings is driven by a transmembrane proton-motive force, and they turn against a surface provided by another membrane protein, known as subunit a. Together, the rotating c-ring and the static subunit a provide a pathway for protons through the membrane in which the c-ring and subunit a are embedded. Vertebrate and invertebrate c-subunits are well conserved. In the structure of the bovine F1-ATPase-c-ring subcomplex, the 75 amino acid c-subunit is folded into two transmembrane α-helices linked by a short loop. Each bovine rotor-ring consists of eight c-subunits with the N- and C-terminal α-helices forming concentric inner and outer rings, with the loop regions exposed to the phospholipid head-group region on the matrix side of the inner membrane. Lysine-43 is in the loop region and its ε-amino group is completely trimethylated. The role of this modification is unknown. If the trimethylated lysine-43 plays some important role in the functioning, assembly or degradation of the c-ring, it would be expected to persist throughout vertebrates and possibly invertebrates also. Therefore, we have carried out a proteomic analysis of c-subunits across representative species from different classes of vertebrates and from invertebrate phyla. In the twenty-nine metazoan species that have been examined, the complete methylation of lysine-43 is conserved, and it is likely to be conserved throughout the more than two million extant metazoan species. In unicellular eukaryotes and prokaryotes, when the lysine is conserved it is unmethylated, and the stoichiometries of c-subunits vary from 9–15. One possible role for the trimethylated residue is to provide a site for the specific binding of cardiolipin, an essential component of ATP synthases in mitochondria. PMID:25608518

  18. Increased Na+/K(+)-pump activity and adenosine triphosphate utilization after compound 48/80-induced histamine secretion from rat mast cells

    DEFF Research Database (Denmark)

    Johansen, Torben; Praetorius, Birger Hans

    1994-01-01

    -production were measured by the bioluminescence technique (firefly lantern) and by measurement of the lactate production under anaerobic conditions (antimycin A, oligomycin), respectively. There was an increased requirement for ATP after the secretory response associated with an increased activity of the Na...

  19. Effect of adenosine triphosphate on triggers arrhythmias%三磷酸腺苷对触发性心律失常的影响

    Institute of Scientific and Technical Information of China (English)

    李家殊; 余更生; 钱永如

    2003-01-01

    目的研究三磷酸腺苷(ATP)对正常和存在触发活动的心脏电生理作用,以探讨ATP致室性心律失常的机制.方法应用接触电极记录心内膜单相动作电位(MAP)技术,观察ATP静脉快速注射对正常心脏MAP变化和氯化铯(CsCl)诱发触发活动时观察应用ATP对心脏的影响.结果 ATP对正常心脏的MAP振幅(MAPA)和0相最大上升速率(Vmax)影响不大,在初期心率减慢不明显,MAP时程(MAPD90)明显延长,并能诱发早期后除极(EAD),后期心率明显抑制,EAD消失,而对存在氯化铯(CsCl)诱发出EAD的心脏,具有双重作用,在作用初期对后除极(EAD或DAD)具有短暂促进作用,而后迅速抑制.结论 ATP对不同心脏状态,有不同作用,表现为兴奋和抑制双重作用,并具有剂量相关性,值得临床重视.

  20. [The adenosine-5'-triphosphate (ATP) test: a diagnostic tool in the management of syncope of unknown origin. Basic and clinical aspects].

    Science.gov (United States)

    Flammang, D; Benditt, D; Pelleg, A

    2005-06-01

    The prevalence of syncope increases in elderly population. An inappropriate reflex reaction of the autonomous nervous system in specific circumstances is responsible for symptoms in more than 50% of cases. These neurocardiogenic or vasovagal syncopes are due to a vasoplegia or to a cardio-inhibitory reflex or to the association of both mechanisms. Reproducing the symptoms may contribute to identify the responsible mechanism of syncope; this objective is partly reached by the head-up tilt test--a provocative test--which reproduces symptoms in about half of the cases, mainly by provoking a severe vasodilation with fall of blood pressure. On the opposite, the ATP test (20 mg i.v. bolus)--a descriptive test--provokes a strong cardio-inhibitory reflex independent from external factors like body position but it must be undertaken in a calm environment for preventing any anticipative sympathetic reaction. The test is considered positive if ATP produces a cardiac pause longer than 10 seconds and related symptoms are not taken into account for assessing the final result. ATP test positivity increases with age and with the presence of cardiac diseases. Permanent dual chamber pacing at 70 bpm has been shown to reduce significantly the syncope recurrences in patients with positive ATP test and to have no influence on patients with a negative test. The use of ATP test should be extended to all syncope screening. Its positivity identifies a group of patients in whom the mechanism of the syncope is susceptible to be improved by a permanent dual chamber pacing. PMID:15991471

  1. PREDICTING BIOTRANSFORMATIONS IN THE SUBSURFACE: RELATIONSHIP BETWEEN THE ATP (ADENOSINE TRIPHOSPHATE) CONTENT OF SUBSURFACE MATERIAL AND THE CAPACITY OF SUBSURFACE ORGANISMS TO DEGRADE TOLUENE

    Science.gov (United States)

    Deeper subsurface material was collected in a manner that prevented contamination by surface microorganisms. This material was analyzed for ATP content, and for its capacity to degrade toluene, a common organic contaminant of ground water originating from release of petroleum pro...

  2. Studies on adenosine triphosphate transphosphorylases. Human isoenzymes of adenylate kinase: isolation and physicochemical comparison of the crystalline human ATP-AMP transphosphorylases from muscle and liver.

    Science.gov (United States)

    Kuby, S A; Fleming, G; Frischat, A; Cress, M C; Hamada, M

    1983-02-10

    Procedures are described for the isolation, in crystalline form, of the adenylate kinases from autopsy samples of human muscle and from human liver. Weight average molecular weights were determined by sedimentation equilibrium to be 22,000 (+/- 700) and 25,450 (+/- 160) for the human muscle and liver isoenzymes, respectively. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis, their molecular weights were estimated to be 21,700 and 26,500 for the muscle and liver enzymes, respectively. Both isoenzymes are accordingly monomeric proteins in their native state. Amino acid analyses are reported here for the normal human liver, calf liver, and rabbit liver adenylate kinases and compared with the normal human muscle, calf muscle, and rabbit muscle myokinases. The liver types as a group and the muscle types as a group show a great deal of homology, but some distinct differences are evident between the liver and muscle enzyme groups, especially in the number of residues of His, Pro, half-cystine, and the presence of tryptophan in the liver enzymes. The normal human liver adenylate kinase, as isolated in this report, has proved to be similar in its properties, if not identical, to the adenylate kinase isolated directly from human liver mitochondria (Hamada, M., Sumida, M., Okuda, H., Watanabe, T., Nojima, M., and Kuby, S. A. (1982) J. Biol. Chem. 257, 13120-13128). Therefore, the liver-type adenylate kinase may be considered a mitochondrial type.

  3. Increased deoxythymidine triphosphate levels is a feature of relative cognitive decline

    DEFF Research Database (Denmark)

    Madsen, Claus Desler; Frederiksen, Jane H; Olsen, Maria Nathalie Angleys;

    2015-01-01

    PBMC content of deoxythymidine-triphosphate (dTTP) (20%), but not mitochondrial bioenergetics parameters measured in this study or mitochondrial ROS. Levels of dTTP in PBMCs are indicators of relative cognitive change suggesting a role of deoxyribonucleotides in the etiology of AD....

  4. Guanosine triphosphate cyclohydrolase 1 promoter deletion causes dopa-responsive dystonia

    NARCIS (Netherlands)

    Theuns, Jessie; Crosiers, David; Debaene, Luc; Nuytemans, Karen; Meeus, Bram; Sleegers, Kristel; Goossens, Dirk; Corsmit, Ellen; Elinck, Ellen; Peeters, Karin; Mattheijssens, Maria; Pickut, Barbara; Del-Favero, Jurgen; Engelborghs, Sebastiaan; De Deyn, Peter Paul; Cras, Patrick; Van Broeckhoven, Christine

    2012-01-01

    Background: Autosomal dominant dopa-responsive dystonia (AD-DRD) is caused by a biochemical defect primarily resulting from guanosine triphosphate cyclohydrolase 1 gene (GCH1) mutations. Few families have been reported without mutations in GCH1. Methods: Genome-wide linkage analysis and positional c

  5. Modulation of bladder function by luminal adenosine turnover and A1 receptor activation

    OpenAIRE

    Prakasam, H. Sandeep; Herrington, Heather; Roppolo, James R.; Jackson, Edwin K.; Apodaca, Gerard

    2012-01-01

    The bladder uroepithelium transmits information to the underlying nervous and musculature systems, is under constant cyclical strain, expresses all four adenosine receptors (A1, A2A, A2B, and A3), and is a site of adenosine production. Although adenosine has a well-described protective effect in several organs, there is a lack of information about adenosine turnover in the uroepithelium or whether altering luminal adenosine concentrations impacts bladder function or overactivity. We observed ...

  6. Inhibition of uptake of adenosine into human blood platelets

    NARCIS (Netherlands)

    Lips, J.P.M.; Sixma, J.J.; Trieschnigg, A.C.

    1980-01-01

    Adenosine transport into human blood platelets is mediated by two independent systems with different affinities. Both systems transport only purine nucleosides and no pyrimidine nucleosides. In experiments with differently substituted purine nucleosides, purines and analogues, differences in carrier

  7. Distribution of adenosine receptors in human sclera fibroblasts

    OpenAIRE

    Cui, Dongmei; Trier, Klaus; Chen, Xiang; Zeng, Junwen; Yang, Xiao; Hu, Jianmin; Ge, Jian

    2008-01-01

    Purpose Systemic treatment with adenosine receptor antagonists has been reported to affect the biochemistry and ultrastructure of rabbit sclera. This study was conducted to determine whether adenosine receptors (ADORs) are present in human scleral fibroblasts (HSF). Methods Primary HSF were cultured in vitro and identified with anti-vimentin, anti-keratin, anti-desmin, and anti-S-100 antibodies. Confocal fluorescence microscopy was used to study the distribution of ADORs in the HSF cell lines...

  8. Structural basis and evolution of redox regulation in plant adenosine-5;#8242;-phosphosulfate kinase

    Energy Technology Data Exchange (ETDEWEB)

    Ravilious, Geoffrey E.; Nguyen, Amelia; Francois, Julie A.; Jez, Joseph M. (WU)

    2012-05-08

    Adenosine-5'-phosphosulfate (APS) kinase (APSK) catalyzes the phosphorylation of APS to 3'-phospho-APS (PAPS). In Arabidopsis thaliana, APSK is essential for reproductive viability and competes with APS reductase to partition sulfate between the primary and secondary branches of the sulfur assimilatory pathway; however, the biochemical regulation of APSK is poorly understood. The 1.8-{angstrom} resolution crystal structure of APSR from A. thaliana (AtAPSK) in complex with {beta},{gamma}-imidoadenosine-5'-triphosphate, Mg{sup 2+}, and APS provides a view of the Michaelis complex for this enzyme and reveals the presence of an intersubunit disulfide bond between Cys86 and Cys119. Functional analysis of AtAPSK demonstrates that reduction of Cys86-Cys119 resulted in a 17-fold higher kcat/Km and a 15-fold increase in Ki for substrate inhibition by APS compared with the oxidized enzyme. The C86A/C119A mutant was kinetically similar to the reduced WT enzyme. Gel- and activity-based titrations indicate that the midpoint potential of the disulfide in AtAPSK is comparable to that observed in APS reductase. Both cysteines are invariant among the APSK from plants, but not other organisms, which suggests redox-control as a unique regulatory feature of the plant APSK. Based on structural, functional, and sequence analyses, we propose that the redox-sensitive APSK evolved after bifurcation of the sulfur assimilatory pathway in the green plant lineage and that changes in redox environment resulting from oxidative stresses may affect partitioning of APS into the primary and secondary thiol metabolic routes by having opposing effects on APSK and APS reductase in plants.

  9. Role of A3 adenosine receptor in diabetic neuropathy.

    Science.gov (United States)

    Yan, Heng; Zhang, Enshui; Feng, Chang; Zhao, Xin

    2016-10-01

    Neuropathy is the most common diabetic complication. Although the A1 and A2A adenosine receptors are important pharmacological targets in alleviating diabetic neuropathy, the role of the A3 adenosine receptor remains unknown. Because the A3 adenosine receptor regulates pain induced by chronic constriction injury or chemotherapy, its stimulation might also attenuate diabetic neuropathy. This study examines the effects of systemic treatment with the A3 adenosine receptor agonist 1-deoxy-1-[6-[[(3-iodophenyl)methyl]amino]-9H-purin-9-yl]-N-methyl-β-d-ribofuranuronamide (IB-MECA) on diabetic neuropathy and explores the putative mechanisms underlying its pharmacological effects. We show that IB-MECA alleviated mechanical hyperalgesia and thermal hypoalgesia in mice 2 weeks but not 4 weeks after streptozocin (STZ) treatment. Furthermore, IB-MECA prevented the reduction in sciatic motor nerve conduction velocity and sensory nerve conduction velocity in diabetic mice 2 weeks but not 4 weeks after STZ treatment. Similarly, IB-MECA inhibited the activation of nuclear factor-κB and decreased the generation of tumor necrosis factor-α in the spinal cord of mice 2 weeks but not 4 weeks after STZ treatment. These phenomena were associated with reduction of A3 adenosine receptor expression in the spinal cord after long-term diabetes. Our results suggest that the A3 adenosine receptor plays a critical role in regulating diabetic neuropathy and that reduction in A3 adenosine receptor expression/function might contribute to the progression of diabetic neuropathy. © 2016 Wiley Periodicals, Inc.

  10. Purification, crystallization and preliminary crystallographic analysis of deoxyuridine triphosphate nucleotidohydrolase from Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Bajaj, Mamta [School of Biological Sciences, University of Nebraska-Lincoln, Manter Hall, Lincoln, Nebraska 68588-0304 (United States); Moriyama, Hideaki, E-mail: hmoriyama2@unl.edu [Department of Chemistry, e-Toxicology and Biotechnology, University of Nebraska-Lincoln, Hamilton Hall, Lincoln, Nebraska 68588-0304 (United States); School of Biological Sciences, University of Nebraska-Lincoln, Manter Hall, Lincoln, Nebraska 68588-0304 (United States)

    2007-05-01

    The first crystallization of deoxyuridine triphosphate nucleotidohydrolase from plant, Arabidopsis thaliana, has been performed. An additive, taurine, was effective in producing the single crystal. The deoxyuridine triphosphate nucleotidohydrolase gene from Arabidopsis thaliana was expressed and the gene product was purified. Crystallization was performed by the hanging-drop vapour-diffusion method at 298 K using 2 M ammonium sulfate as the precipitant. X-ray diffraction data were collected to 2.2 Å resolution using Cu Kα radiation. The crystal belongs to the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 69.90, b = 70.86 Å, c = 75.55 Å. Assuming the presence of a trimer in the asymmetric unit, the solvent content was 30%, with a V{sub M} of 1.8 Å{sup 3} Da{sup −1}.

  11. Description of a novel eukaryotic deoxyuridine 5'-triphosphate nucleotidohydrolase in Leishmania major

    DEFF Research Database (Denmark)

    Camacho, A; Arrebola, R; Pena Diaz, Javier;

    1997-01-01

    . None of the characteristic motifs were readily identifiable and the sequence encoded a larger polypeptide. However, the products of the reaction were dUMP and PPi, competition experiments with other deoxyribonucleoside triphosphates showed that the reaction is specific for dUTP, and the protozoan gene...... of recombinant enzyme in large quantities will now permit detailed mechanistic and structural studies, which might contribute to a rational design of specifically targeted inhibitors against dUTPase from L. major....

  12. Intracoronary adenosine improves myocardial perfusion in late reperfused myocardial infarction

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Background Myocardial perfusion associates with clinical syndromes and prognosis.Adenosine could improve myocardial perfusion of acute myocardial infarction within 6 hours,but few data are available on late perfusion of myocardial infarction (MI).This study aimed at quantitatively evaluating the value of intracoronary adenosine improving myocardial perfusion in late reperfused MI with myocardial contrast echocardiography(MCE).Methods Twenty-six patients with anterior wall infarcts were divided randomly into 2 groups:adenosine group(n=12) and normal saline group(n=14).Their history of myocardial infarction was about 3-12 weeks.Adenosine or normalsaline was given when the guiding wire crossed the lesion through percutaneous coronary intervention(PCI),then the balloon was dilated and stent(Cypher/Cypher select)was implanted at the lesion.Contrast pulse sequencing MCE with Sonovue contrast via the coronary route was done before PCI and 30 minutes after PCI.Video densitometry and contrast filled-blank area were calculated with the CUSQ off-line software.Heart function and cardiac events were followed up within 30 days.Results Perfusion in the segments of the criminal occlusive coronary artery in the adenosine group was better than that in the saline group(5.71±0.29 vs 4.95±1.22,P<0.05).Ischemic myocardial segment was deminished significantly afterPCI,but the meliorated area was bigger in the adenosine group than in the saline group((1.56±0.60)cm2 vs(1.02±0.56) cm2,P<0.05).The video densitometry in critical segments was also improved significantly in the adenosine group (5.53±0.36 vs 5.26±0.35,P<0.05).Left ventricular ejection fraction(LVEF)was improved in all patients after PCI,but EF was not significant between the two groups((67±6)% vs(62±7)%,P>0.05).There was no in-hospital or 30-day major adverse cardiac event(MACE)in the adenosine group but 3 MACE in the saline group in 30 days after PCI.Conclusions Adenosine could improve myocardial microvascular

  13. Antagonism by theophylline of respiratory inhibition induced by adenosine.

    Science.gov (United States)

    Eldridge, F L; Millhorn, D E; Kiley, J P

    1985-11-01

    The effects on respiration of an analogue of adenosine, L-2-N6-(phenylisopropyl)adenosine (PIA), and of the methylxanthine, theophylline, were determined in 19 vagotomized glomectomized cats whose end-tidal PCO2 was kept constant by means of a servo-controlled ventilator. Integrated phrenic nerve activity was used to represent respiratory output. Our results show that PIA, whether given systemically or into the third cerebral ventricle, depressed respiration. Systemically administered theophylline stimulated respiration. Theophylline given intravenously, or into the third ventricle not only reversed the depressive effects of previously administered PIA but caused further increases of respiration above the control level. Prior systemic administration of theophylline blocked both respiratory and hypotensive effects of subsequently administered PIA. Effects of either agent on medullary extracellular fluid pH did not explain the results. We conclude that the adenosine analogue PIA, acts to inhibit neurons in the brain that are involved in the control of respiration and that its effects are blocked by theophylline. We suggest that adenosine acts as a tonic modulator of respiration and that theophylline stimulates breathing by competitive antagonism of adenosine at neuronal receptor sites. PMID:4066573

  14. Adenosine A1 receptor agonists inhibit trigeminovascular nociceptive transmission

    DEFF Research Database (Denmark)

    Goadsby, P J; Hoskin, K L; Storer, R J;

    2002-01-01

    There is a considerable literature to suggest that adenosine A1 receptor agonists may have anti-nociceptive effects, and we sought to explore the role of adenosine A1 receptors in a model of trigeminovascular nociceptive transmission. Cats were anaesthetized (alpha-chloralose 60 mg/kg, intraperit......There is a considerable literature to suggest that adenosine A1 receptor agonists may have anti-nociceptive effects, and we sought to explore the role of adenosine A1 receptors in a model of trigeminovascular nociceptive transmission. Cats were anaesthetized (alpha-chloralose 60 mg...... from the external jugular vein to determine levels of calcitonin gene-related peptide (CGRP) release before and after drug administration. Intravenous administration of the highly selective adenosine A1 receptor agonist, GR79236 (3-100 microg/kg) had a dose-dependent inhibitory effect on SSS...... 33 +/- 2 pmol/l (n = 6) to 64 +/- 3 pmol/l, an effect substantially reduced by pre-treatment with GR79236 (30 microg/kg; P agonist, GR190178 (30-1000 microg/kg i.v.), also inhibited SSS-evoked neuronal activity in a dose-dependent fashion...

  15. Modulating effect of adenosine deaminase on function of adenosine A1receptors

    Institute of Scientific and Technical Information of China (English)

    Wan-chun SUN; Yan CAO; Lei JIN; Li-zhen WANG; Fan MENG; Xing-zu ZHU

    2005-01-01

    Aim: To study the modulating effect of adenosine deaminase (ADA) on yhe adenosine A1 receptor (A1R) in HEK293 cells stably expressing the human A1R.Methods: cDNA was amplified by RT-PCR using total RNA from human embryo brain tissue as the template. The PCR products were subcloned into the plasmid pcDNA3 and cloned into the plasmid pcDNA3.1. The cloned A1R cDNA was sequenced and stably expressed in HEK293 cells. The modulating effect of adenosine deaminase on A1R was studied by using [3H]DPCPX binding assay and an intracellular calcium assay. Results: HEK293 cells stably expressing human A1R were obtained. Saturation studies showed that the KD value and Bmax value of [3H]DPCPX were 1.6±0.2 nmol/L and 1.819±0.215 nmol/g of protein respectively, in the absence of ecto-ADA respectively, and 1.3±0.2 nmol/L and 1.992±0.130 nmol/g of protein in the presence of ecto-ADA respectively, suggesting that the KD value and Bmax value of [3H]DPCPX were unaffected by ecto-ADA. In the case of [3H]DPCPX competition curves obtained from intact cells or membranes, A1R agonist CCPA/[3H]DPCPX competition curve could be fitted well to a one-site model in the absence of ecto-ADA and a two-site model in the presence of ecto ADA with a KH value of 0.74 (0.11-4.8) nmol/L (intact cells) or 1.8 (0.25-10) nmol/L (membrane) and a KL value of 0.94 (0.62-1.41) μmol/L (intact cells) or 0.77 (0.29-0.99) μmol/L (membrane). The KL value is not significantly different from the IC50 value of 0.84(0.57-1.23) μmol/L (intact cells) or 0.84 (0.63-1.12) μmol/L (membrane) obtained in the absence of ecto-ADA. Similar results were obtained from the CPA/[3H]DPCPX competition curve in the absence or presence of ecto-ADA on intact cells or membranes. Intracellular calcium assay demonstrated that the EC50 value of CPA were 10 (5-29) nmol/L and 94 (38-229) nmol/L in the presence or absence of ecto-ADA, respectively. Conclusion: A1R stably expressed in the HEK293 cells display a low affinity for agonists in

  16. Thallium-201 scintigraphy of the myocardium in connection with adenosine

    International Nuclear Information System (INIS)

    It is shown that thallium-201 SPECT studies of the myocardium performed subsequent to intravenous infusion of adenosine provide results at least as valuable as those from exercise thallium-201 scintigraphy in the diagnosis of coronary artery disease. The infusion of adenosine offers great advantages over exercise studies in that it is a standardized procedure uninfluenced by a patient's physical fitness, which can thus be used in all cases. There are quite a number of clinically tolerable untoward reactions that may be associated with discomfort but do not warrant discontinuation of the procedure. Serious, verifiable side-effects are rare and disappear immediately on termination of the infusion. The most recent research in this field has shown that newly developed compounds of 99mTc are also suitable for radionuclide studies of the myocardium with adenosine vasodilation. (orig.)

  17. Role of adenosine as adjunctive therapy in acute myocardial infarction.

    Science.gov (United States)

    Forman, Mervyn B; Stone, Gregg W; Jackson, Edwin K

    2006-01-01

    Although early reperfusion and maintained patency is the mainstay therapy for ST elevation myocardial infarction, experimental studies demonstrate that reperfusion per se induces deleterious effects on viable ischemic cells. Thus "myocardial reperfusion injury" may compromise the full potential of reperfusion therapy and may account for unfavorable outcomes in high-risk patients. Although the mechanisms of reperfusion injury are complex and multifactorial, neutrophil-mediated microvascular injury resulting in a progressive decrease in blood flow ("no-reflow" phenomenon) likely plays an important role. Adenosine is an endogenous nucleoside found in large quantities in myocardial and endothelial cells. It activates four well-characterized receptors producing various physiological effects that attenuate many of the proposed mechanisms of reperfusion injury. The cardio-protective effects of adenosine are supported by its role as a mediator of pre- and post-conditioning. In experimental models, administration of adenosine in the peri-reperfusion period results in a marked reduction in infarct size and improvement in ventricular function. The cardioprotective effects in the canine model have a narrow time window with the drug losing its effect following three hours of ischemia. Several small clinical studies have demonstrated that administration of adenosine with reperfusion therapy reduces infarct size and improves ventricular function. In the larger AMISTAD and AMISTAD II trials a 3-h infusion of adenosine as an adjunct to reperfusion resulted in a striking reduction in infarct size (55-65%). Post hoc analysis of AMISTAD II showed that this was associated with significantly improved early and late mortality in patients treated within 3.17 h of symptoms. An intravenous infusion of adenosine for 3 h should be considered as adjunctive therapy in high risk-patients undergoing reperfusion therapy. PMID:16961725

  18. Investigating real-time activation of adenosine receptors by bioluminescence resonance energy transfer technique

    Science.gov (United States)

    Huang, Yimei; Yang, Hongqin; Zheng, Liqin; Chen, Jiangxu; Wang, Yuhua; Li, Hui; Xie, Shusen

    2013-02-01

    Adenosine receptors play important roles in many physiological and pathological processes, for example regulating myocardial oxygen consumption and the release of neurotransmitters. The activations of adenosine receptors have been studied by some kinds of techniques, such as western blot, immunohistochemistry, etc. However, these techniques cannot reveal the dynamical response of adenosine receptors under stimulation. In this paper, bioluminescence resonance energy transfer technique was introduced to study the real-time activation of adenosine receptors by monitoring the dynamics of cyclic adenosine monophosphate (cAMP) level. The results showed that there were significant differences between adenosine receptors on real-time responses under stimulation. Moreover, the dynamics of cAMP level demonstrated that competition between adenosine receptors existed. Taken together, our study indicates that monitoring the dynamics of cAMP level using bioluminescence resonance energy transfer technique could be one potential approach to investigate the mechanism of competitions between adenosine receptors.

  19. Phosphorylation of adenosine with trimetaphosphate under simulated prebiotic conditions.

    Science.gov (United States)

    Cheng, Changmei; Fan, Chang; Wan, Rong; Tong, Chunyuan; Miao, Zhiwei; Chen, Jing; Zhao, Yufen

    2002-06-01

    The phosphorylation of adenosine with trimetaphosphate in solution, in solid phase and using wet-dry cycles was carried out and it was found that wet-dry cycles were the most efficient. The catalytic effects of some metal ions on the phosphorylation were also studied and it was discovered that Ni(II) is the most effective. The combination of wet-dry cycles (4 cycles) and catalysis by Ni(II) led to an unprecedented high conversion of adenosine to phosphorylated products (30%) near neutral pH. The main phosphorylated products were 2',3'-cyclic AMP (10.4%) and 5'-ATP (13.0%). PMID:12227426

  20. No role of interstitial adenosine in insulin-mediated vasodilation

    DEFF Research Database (Denmark)

    Dela, F; Stallknecht, B

    1999-01-01

    healthy subjects (H) and in four subjects with a complete, high (C5-C6/7) spinal cord injury (SCI) a hyperinsulinaemic (480 mU min-1 kg-1), isoglycaemic clamp was performed. SCI subjects were included as it has been proposed that adenosine and adenine nucleotides may be released from nerve endings in the...... skeletal muscle. Adenosine concentrations in the extracellular fluid (ECF) of skeletal muscle in the thigh were measured by means of the microdialysis technique. Leg blood flow (LBF) was measured by termodilution. In response to insulin infusion, LBF always increased (P < 0.05) (from 228 +/- 25 and 318...

  1. Why do premature newborn infants display elevated blood adenosine levels?

    Science.gov (United States)

    Panfoli, Isabella; Cassanello, Michela; Bruschettini, Matteo; Colella, Marina; Cerone, Roberto; Ravera, Silvia; Calzia, Daniela; Candiano, Giovanni; Ramenghi, Luca

    2016-05-01

    Our preliminary data show high levels of adenosine in the blood of very low birth weight (VLBW) infants, positively correlating to their prematurity (i.e. body weight class). This prompted us to look for a mechanism promoting such impressive adenosine increase. We hypothesized a correlation with oxygen challenge. In fact, it is recognized that either oxygen lack or its excess contribute to the pathogenesis of the injuries of prematurity, such as retinopathy (ROP) and periventricular white matter lesions (PWMI). The optimal concentration of oxygen for resuscitation of VLBW infants is currently under revision. We propose that the elevated adenosine blood concentrations of VLBW infants recognizes two sources. The first could be its activity-dependent release from unmyelinated brain axons. Adenosine in this respect would be an end-product of the hypometabolic VLBW newborn unmyelinated axon intensely firing in response to the environmental stimuli consequent to premature birth. Adenosine would be eventually found in the blood due to blood-brain barrier immaturity. In fact, adenosine is the primary activity-dependent signal promoting differentiation of premyelinating oligodendrocyte progenitor cells (OPC) into myelinating cells in the Central Nervous System, while inhibiting their proliferation and inhibiting synaptic function. The second, would be the ecto-cellular ATP synthesized by the endothelial cell plasmalemma exposed to ambient oxygen concentrations due to premature breathing, especially in lung. ATP would be rapidly transformed into adenosine by the ectonucleotidase activities such as NTPDase I (CD39), and NT5E (CD73). An ectopic extra-mitochondrial aerobic ATP synthetic ability was reported in many cell plasma-membranes, among which endothelial cells. The potential implications of the cited hypotheses for the neonatology area would be great. The amount of oxygen administration for reviving of newborns would find a molecular basis for its assessment. VLBW

  2. Cytotoxic purine nucleoside analogues bind to A1, A2A and A3 adenosine receptors

    OpenAIRE

    Jensen, Kyle; Johnson, L’Aurelle A.; Jacobson, Pamala A.; Kachler, Sonja; Kirstein, Mark N.; Lamba, Jatinder; Klotz, Karl-Norbert

    2012-01-01

    Fludarabine, clofarabine and cladribine are anti-cancer agents which are analogues of the purine nucleoside adenosine. These agents have been associated with cardiac and neurological toxicities. Because these agents are analogues of adenosine, they may act through adenosine receptors to elicit their toxic effects. The objective of this study was to evaluate the ability of cytotoxic nucleoside analogues to bind and activate adenosine receptor subtypes (A1, A2A, A2B, and A3). Radioligand bindin...

  3. Development of coronary vasospasm during adenosine-stress myocardial perfusion CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Jeong Gu; Choi, Seong Hoon; Kang, Byeong Seong; Bang, Min Aeo; Kwon, Woon Jeong [Dept. of Radiology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan (Korea, Republic of)

    2015-06-15

    Adenosine is a short-acting coronary vasodilator, and it is widely used during pharmacological stress myocardial perfusion imaging. It has a well-established safety profile, and most of its side effects are known to be mild and transient. Until now, coronary vasospasm has been rarely reported as a side effect of adenosine during or after adenosine stress test. This study reports a case of coronary vasospasm which was documented on stress myocardial perfusion CT imaging during adenosine stress test.

  4. The adenosine metabolite inosine is a functional agonist of the adenosine A2A receptor with a unique signaling bias.

    Science.gov (United States)

    Welihinda, Ajith A; Kaur, Manmeet; Greene, Kelly; Zhai, Yongjiao; Amento, Edward P

    2016-06-01

    Inosine is an endogenous purine nucleoside that is produced by catabolism of adenosine. Adenosine has a short half-life (approximately 10s) and is rapidly deaminated to inosine, a stable metabolite with a half-life of approximately 15h. Resembling adenosine, inosine acting through adenosine receptors (ARs) exerts a wide range of anti-inflammatory and immunomodulatory effects in vivo. The immunomodulatory effects of inosine in vivo, at least in part, are mediated via the adenosine A2A receptor (A2AR), an observation that cannot be explained fully by in vitro pharmacological characterization of inosine at the A2AR. It is unclear whether the in vivo effects of inosine are due to inosine or a metabolite of inosine engaging the A2AR. Here, utilizing a combination of label-free, cell-based, and membrane-based functional assays in conjunction with an equilibrium agonist-binding assay we provide evidence for inosine engagement at the A2AR and subsequent activation of downstream signaling events. Inosine-mediated A2AR activation leads to cAMP production with an EC50 of 300.7μM and to extracellular signal-regulated kinase-1 and -2 (ERK1/2) phosphorylation with an EC50 of 89.38μM. Our data demonstrate that inosine produces ERK1/2-biased signaling whereas adenosine produces cAMP-biased signaling at the A2AR, highlighting pharmacological differences between these two agonists. Given the in vivo stability of inosine, our data suggest an additional, previously unrecognized, mechanism that utilizes inosine to functionally amplify and prolong A2AR activation in vivo. PMID:26903141

  5. DMPD: Shaping of monocyte and macrophage function by adenosine receptors. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17056121 Shaping of monocyte and macrophage function by adenosine receptors. Hasko ...tml) (.csml) Show Shaping of monocyte and macrophage function by adenosine receptors. PubmedID 17056121 Titl...e Shaping of monocyte and macrophage function by adenosine receptors. Authors Has

  6. Searching Inhibitors of Adenosine Kinase by Simulation Methods

    Institute of Scientific and Technical Information of China (English)

    ZHU Rui-Xin; ZHANG Xing-Long; DONG Xi-Cheng; CHEN Min-Bo

    2006-01-01

    Searching new inhibitors of adenosine kinase (AK) is still drawing attention of experimental scientists. A better and solid model is here proposed by means of simulation methods from different ways, the direct analysis of receptor itself, the conventional 3D-QSAR methods and the integration of docking method and the conventional QSAR analysis.

  7. Vasoconstrictor and vasodilator effects of adenosine in the kidney

    DEFF Research Database (Denmark)

    Hansen, Pernille B; Schnermann, Jurgen

    2003-01-01

    that the steady-state response to the increase of plasma adenosine levels above normal resulting from the infusion is global renal vasorelaxation that is the result of A2AR activation in most parts of the renal vasculature, including larger renal arteries, juxtamedullary afferent arterioles, efferent arterioles...

  8. Fluorescent Structural DNA Nanoballs Functionalized With Phosphate-Linked Nucleotide Triphosphates

    Science.gov (United States)

    Anderson, Jon P.; Reynolds, Bambi L.; Baum, Kristin; Williams, John G.

    2010-01-01

    Highly labeled DNA nanoballs functionalized with phosphate-linked nucleotide triphosphates (dNTPs) were developed as a source of dNTPs for DNA polymerase. The particles were prepared by strand-displacement polymerization from a self-complementary circular template. Imaged by atomic force microscopy, these functionalized particles appear as condensed fuzzy balls with diameters between 50–150 nm. They emit a bright fluorescent signal, detected in 2 msec exposures with a signal-to-noise of 25 when imaged using a TIR fluorescence microscope. PMID:20158249

  9. Synthesis of Nucleoside Triphosphates from 2'-3'-Protected Nucleosides Using Trimetaphosphate.

    Science.gov (United States)

    Mohamady, Samy; Taylor, Scott D

    2016-02-01

    Chemists have been attempting to triphosphorylate nucleosides and other alcohols using trimetaphosphate (TriMP) since the 1960s. However, this route appears to have been abandoned due to poor yields. The first practical syntheses of nucleoside triphosphates (NTPs) are reported using TriMP as the key reagent. This was achieved by reacting the tetrabutylammonium salt of TriMP with mesitylenesulfonyl chloride in the presence of DABCO in pyridine followed by the addition of an appropriately protected nucleoside and phthalimide. Quenching the reaction with aqueous buffer followed by hydrolysis of the OH protecting groups gave the NTPs in good yield. PMID:26759914

  10. Chloride permeability of rat brain membrane vesicles correlates with thiamine triphosphate content.

    Science.gov (United States)

    Bettendorff, L; Hennuy, B; De Clerck, A; Wins, P

    1994-07-25

    Incubation of rat brain homogenates with thiamine or thiamine diphosphate (TDP) leads to a synthesis of thiamine triphosphate (TTP). In membrane vesicles subsequently prepared from the homogenates, increased TTP content correlates with increased 36Cl- uptake. A hyperbolic relationship was obtained with a K0.5 of 0.27 nmol TTP/mg protein. In crude mitochondrial fractions from the brains of animals previously treated with thiamine or sulbutiamine, a positive correlation between 36Cl- uptake and TTP content was found. These results, together with other results previously obtained with the patch-clamp technique, suggest that TTP is an activator of chloride channels having a large unit conductance. PMID:7953714

  11. Feed-Forward Inhibition of CD73 and Upregulation of Adenosine Deaminase Contribute to the Loss of Adenosine Neuromodulation in Postinflammatory Ileitis

    Directory of Open Access Journals (Sweden)

    Cátia Vieira

    2014-01-01

    Full Text Available Purinergic signalling is remarkably plastic during gastrointestinal inflammation. Thus, selective drugs targeting the “purinome” may be helpful for inflammatory gastrointestinal diseases. The myenteric neuromuscular transmission of healthy individuals is fine-tuned and controlled by adenosine acting on A2A excitatory receptors. Here, we investigated the neuromodulatory role of adenosine in TNBS-inflamed longitudinal muscle-myenteric plexus of the rat ileum. Seven-day postinflammation ileitis lacks adenosine neuromodulation, which may contribute to acceleration of gastrointestinal transit. The loss of adenosine neuromodulation results from deficient accumulation of the nucleoside at the myenteric synapse despite the fact that the increases in ATP release were observed. Disparity between ATP outflow and adenosine deficit in postinflammatory ileitis is ascribed to feed-forward inhibition of ecto-5′-nucleotidase/CD73 by high extracellular ATP and/or ADP. Redistribution of NTPDase2, but not of NTPDase3, from ganglion cell bodies to myenteric nerve terminals leads to preferential ADP accumulation from released ATP, thus contributing to the prolonged inhibition of muscle-bound ecto-5′-nucleotidase/CD73 and to the delay of adenosine formation at the inflamed neuromuscular synapse. On the other hand, depression of endogenous adenosine accumulation may also occur due to enhancement of adenosine deaminase activity. Both membrane-bound and soluble forms of ecto-5′-nucleotidase/CD73 and adenosine deaminase were detected in the inflamed myenteric plexus. These findings provide novel therapeutic targets for inflammatory gut motility disorders.

  12. The Rickettsia prowazekii invasion gene homolog (invA) encodes a Nudix hydrolase active on adenosine (5')-pentaphospho-(5')-adenosine.

    Science.gov (United States)

    Gaywee, Jariyanart; Xu, WenLian; Radulovic, Suzana; Bessman, Maurice J; Azad, Abdu F

    2002-03-01

    The genomic sequence of Rickettsia prowazekii, the obligate intracellular bacterium responsible for epidemic typhus, reveals an uncharacterized invasion gene homolog (invA). The deduced protein of 18,752 Da contains a Nudix signature, the specific motif found in the Nudix hydrolase family. To characterize the function of InvA, the gene was cloned and overexpressed in Escherichia coli. The expressed protein was purified to near homogeneity and subsequently tested for its enzymatic activity against a series of nucleoside diphosphate derivatives. The purified InvA exhibits hydrolytic activity toward dinucleoside oligophosphates (Np(n)N; n > or = 5), a group of cellular signaling molecules. At optimal pH 8.5, the enzyme actively degrades adenosine (5')-pentaphospho-(5')-adenosine into ATP and ADP with a K(m) of 0.1 mM and k(cat) of 1.9 s(-1). Guanosine (5')-pentaphospho-(5')-guanosine and adenosine-(5')-hexaphospho (5')-adenosine are also substrates. Similar to other Nudix hydrolases, InvA requires a divalent metal cation, Mg(2+) or Zn(2+), for optimal activity. These data suggest that the rickettsial invasion protein likely plays a role in controlling the concentration of stress-induced dinucleoside oligophosphates following bacterial invasion.

  13. Discovery of β-D-2'-deoxy-2'-α-fluoro-4'-α-cyano-5-aza-7,9-dideaza adenosine as a potent nucleoside inhibitor of respiratory syncytial virus with excellent selectivity over mitochondrial RNA and DNA polymerases.

    Science.gov (United States)

    Clarke, Michael O; Mackman, Richard; Byun, Daniel; Hui, Hon; Barauskas, Ona; Birkus, Gabriel; Chun, Byoung-Kwon; Doerffler, Edward; Feng, Joy; Karki, Kapil; Lee, Gary; Perron, Michel; Siegel, Dustin; Swaminathan, Swami; Lee, William

    2015-06-15

    Novel 4'-substituted β-d-2'-deoxy-2'-α-fluoro (2'd2'F) nucleoside inhibitors of respiratory syncytial virus (RSV) are reported. The introduction of 4'-substitution onto 2'd2'F nucleoside analogs resulted in compounds demonstrating potent cell based RSV inhibition, improved inhibition of the RSV polymerase by the nucleoside triphosphate metabolites, and enhanced selectivity over incorporation by mitochondrial RNA and DNA polymerases. Selectivity over the mitochondrial polymerases was found to be extremely sensitive to the specific 4'-substitution and not readily predictable. Combining the most potent and selective 4'-groups from N-nucleoside analogs onto a 2'd2'F C-nucleoside analog resulted in the identification of β-D-2'-deoxy-2'-α-fluoro-4'-α-cyano-5-aza-7,9-dideaza adenosine as a promising nucleoside lead for RSV.

  14. Scope and Limitations of Typical Copper-Free Bioorthogonal Reactions with DNA: Reactive 2'-Deoxyuridine Triphosphates for Postsynthetic Labeling.

    Science.gov (United States)

    Merkel, Marcus; Arndt, Stefanie; Ploschik, Damian; Cserép, Gergely B; Wenge, Ulrike; Kele, Péter; Wagenknecht, Hans-Achim

    2016-09-01

    Four triphosphates of 2'-deoxyuridine that carried the following bioorthogonally reactive groups were synthesized by organic-chemical methods. Two triphosphates with tetrazines and one with a cyclopropene moiety were designed for Diels-Alder reactions with inverse electron demand, and one triphosphate with a tetrazole core was designed for the "photoclick" cycloaddition. These triphosphates were not only successfully applied for oligonucleotide preparation by standard DNA polymerases, including Hemo KlenTaq, Vent, and Deep Vent, but also bypassed for full length primer extension products. Fluorescent labeling of the primer extension products was achieved by fluorophores with reactive counterparts and analyzed by polyacrylamide gel electrophoresis mobility shifts. The tetrazine-oligonucleotide conjugates were reacted with carboxymethylmonobenzocyclooctyne- and bicyclononyne-modified fluorophores. The yield of these postsynthetic reactions could significantly be improved by a more stable but still reactive nicotinic acid-derived tetrazine and by changing the key experimental conditions, mainly the pH of 7.2 and the temperature of 45-55 °C. The cyclopropene-oligonucleotide conjugate could be successfully labeled with a tetrazine-modified rhodamine in very good yields. The "photoclick" cycloaddition between tetrazole-oligonucleotide conjugates and a maleimide-modified dye worked quantitatively. The combination of primer extension, bypass, and bioorthogonal modification works also for double and triple labeling using the cyclopropene-modified 2'-deoxyuridine triphosphate. PMID:27513089

  15. Adenosine contributes to blood flow regulation in the exercising human leg by increasing prostaglandin and nitric oxide formation

    DEFF Research Database (Denmark)

    Mortensen, Stefan; Nyberg, Michael; Thaning, Pia;

    2009-01-01

    Adenosine can induce vasodilation in skeletal muscle, but to what extent adenosine exerts its effect via formation of other vasodilators and whether there is redundancy between adenosine and other vasodilators remain unclear. We tested the hypothesis that adenosine, prostaglandins, and NO act in...

  16. Adenosine-mediated modulation of ventral horn interneurons and spinal motoneurons in neonatal mice.

    Science.gov (United States)

    Witts, Emily C; Nascimento, Filipe; Miles, Gareth B

    2015-10-01

    Neuromodulation allows neural networks to adapt to varying environmental and biomechanical demands. Purinergic signaling is known to be an important modulatory system in many parts of the CNS, including motor control circuitry. We have recently shown that adenosine modulates the output of mammalian spinal locomotor control circuitry (Witts EC, Panetta KM, Miles GB. J Neurophysiol 107: 1925-1934, 2012). Here we investigated the cellular mechanisms underlying this adenosine-mediated modulation. Whole cell patch-clamp recordings were performed on ventral horn interneurons and motoneurons within in vitro mouse spinal cord slice preparations. We found that adenosine hyperpolarized interneurons and reduced the frequency and amplitude of synaptic inputs to interneurons. Both effects were blocked by the A1-type adenosine receptor antagonist DPCPX. Analysis of miniature postsynaptic currents recorded from interneurons revealed that adenosine reduced their frequency but not amplitude, suggesting that adenosine acts on presynaptic receptors to modulate synaptic transmission. In contrast to interneurons, recordings from motoneurons revealed an adenosine-mediated depolarization. The frequency and amplitude of synaptic inputs to motoneurons were again reduced by adenosine, but we saw no effect on miniature postsynaptic currents. Again these effects on motoneurons were blocked by DPCPX. Taken together, these results demonstrate differential effects of adenosine, acting via A1 receptors, in the mouse spinal cord. Adenosine has a general inhibitory action on ventral horn interneurons while potentially maintaining motoneuron excitability. This may allow for adaptation of the locomotor pattern generated by interneuronal networks while helping to ensure the maintenance of overall motor output. PMID:26311185

  17. Adenosine receptors and stress : Studies using methylmercury, caffeine and hypoxia

    OpenAIRE

    Björklund, Olga

    2008-01-01

    Brain development is a precisely organized process that can be disturbed by various stress factors present in the diet (e.g. exposure to xenobiotics) as well as insults such as decreased oxygen supply. The consequent adverse changes in nervous system function may not necessarily be apparent until a critical age when neurodevelopmental defects may be unmasked by a subsequent challenge. Adenosine and its receptors (AR) (A1, A2A, A2B and A3) which participate in the brain stres...

  18. Myocardial energy metabolism in ischemic preconditioning, role of adenosine catabolism

    OpenAIRE

    Kavianipour, Mohammad

    2002-01-01

    Brief episodes of ischemia and reperfusion render the myocardium more resistant to necrosis from a subsequent, otherwise lethal ischemic insult. This phenomenon is called ischemic preconditioning(IP). Today, much is known about the signalling pathways involved in IP; however, the details of the final steps leading to cardioprotection, remain elusive. Adenosine (a catabolite of ATP) plays a major role in the signalling pathways of IP. Following IP there is an unexplained discrepancy between an...

  19. Pharmacology of the Adenosine A3 Receptor in the Vasculature and Essential Hypertension

    Science.gov (United States)

    Ho, Ming-Fen; Low, Leanne M.; Rose’Meyer, Roselyn B.

    2016-01-01

    Background Essential hypertension is considered to be a multifactorial disorder and its aetiology has yet to be clearly identified. As the adenosine receptors have a significant role in mediating vasodilation, alterations in their structures or signalling pathways may be involved in the development of hypertension. This study aimed to measure the expression of adenosine A3 receptors in a range of cardiovascular tissues and determine whether they could be altered with essential hypertension, and to functionally test responses to adenosine A3 receptor agonists in coronary blood vessels using the isolated perfused heart preparation. Methods mRNA samples from cardiovascular tissues and a range of blood vessels were collected from 10 week old male spontaneously hypertensive rats and age-gender matched Wistar rats (n = 8). The Langendorff heart perfusion preparation was used to characterise adenosine A3 receptor mediated coronary vasodilation in the rat heart. Results Adenosine A3 receptor agonists induced coronary vasodilation. The expression of adenosine A3 receptors in cardiovascular tissues was altered in a tissue-specific pattern. Specifically, down-regulation of adenosine A3 receptor expression occurred in hypertensive hearts, which might be associated with attenuated vasodilator responses observed in coronary vessels to adenosine A3 receptor agonists. Conclusions This study demonstrated alterations in the expression of adenosine A3 receptors occurred in a tissue specific mode, and reduced adenosine A3 receptor mediated coronary vasodilation in hearts from spontaneously hypertensive rats. Our findings with regard to changes in the adenosine A3 receptor in hypertensive hearts suggest that adenosine A3 receptor might play a role in the physiopathology of essential hypertension and potentially open the way to pharmacologic manipulation of vasomotor activity by the use of adenosine A3 receptor agonists. PMID:26907173

  20. Uridine triphosphate prolongs action potential duration of guinea pig papillary muscles via P2Y2 purinoceptors%尿苷三磷酸通过P2Y2尿嘌呤受体延长豚鼠乳头状肌动作电位时程

    Institute of Scientific and Technical Information of China (English)

    秦葵; 任雷鸣; 赵丁

    2001-01-01

    AIM: To study the electrophysiologic effects of uridine triphosphate (UrrP) on the guinea pig papillary muscles in vitro and purinoceptors related with the action of UTP. METHODS: Intracellular microelectrode method was used to record action potentials (AP) in guinea pig papillary muscles. RESULTS: UTP, adenosine triphosphate (ATP), and adenosine diphosphate (ADP) prolonged the action potential duration (APD) concentration-dependently in guinea pig papillary muscles. The potency order was UTP=ATP>ADP. There was cross-desensitization between the response to ATP and that to UTP, and neither Ado nor a, β-MeATP caused great change in AP of the papillary muscles. The prolongation of APD by UTP was not affected by sustained perfusion with aminophylline. As an osmotic pressure control equivalent to UTP 3 mmol/L, ceftriaxonum 3 mmol/L or NaC1 9 mmol/L induced a marked but slight prolongation of APD. CONCLUSION: UTP produced APD prolongation through specific and nonspecific actions, and the specific response to UTP was mediated by P2Y2 purinoceptors.%目的:研究尿苷三磷酸(UTP)对豚鼠乳头状肌的电生理作用,及UTP作用的相关受体.方法:利用细胞内微电极技术记录豚鼠乳头状肌跨膜电位.结果:UTP、ATP和ADP均可浓度依赖性延长豚鼠乳头状肌动作电位时程(APD).激动剂的效应强度序列为UTP=ATP>ADP,且UTP和ATP的作用存在交叉脱敏现象.Adenosine(Ado)和α,β-methylene ATP(α,β-MeATP)对豚鼠乳头状肌动作电位各参数均无影响,氨茶碱持续灌流亦不影响UTP的作用.与UTP 3 mmol/L等渗的ceftriaxonum(3 mmoL/L)或NaCI(9 mmol/L)可显著但轻微地延长APD.结论:UTP延长豚鼠乳头状肌APD的作用由特异性和非特异性两种作用组成,前者与P2Y2受体有关.

  1. Intracellular signalling pathways in the vasoconstrictor response of mouse afferent arterioles to adenosine

    DEFF Research Database (Denmark)

    Hansen, Pernille B. Lærkegaard; Friis, Ulla Glenert; Uhrenholt, Torben Rene;

    2007-01-01

    calcium from the sarcoplasmic reticulum (SR), stimulated presumably by IP(3), is involved in the adenosine contraction mechanism of the afferent arteriole. In agreement with this notion is the observation that 2 aminoethoxydiphenyl borate (100 microM) blocked the adenosine-induced constriction whereas the...... protein kinase C inhibitor calphostin C had no effect. The calcium-activated chloride channel inhibitor IAA-94 (30 microM) inhibited the adenosine-mediated constriction. Patch clamp experiments showed that adenosine treatment induced a depolarizing current in preglomerular smooth muscle cells which was....... METHODS AND RESULTS: Adenosine (10(-7) M) significantly increased the intracellular calcium concentration in mouse isolated afferent arterioles measured by fura-2 fluorescence. Pre-treatment with thapsigargin (2 microM) blocked the vasoconstrictor action of adenosine (10(-7) M) indicating that release of...

  2. [Effects of dopamine and adenosine on regulation of water-electrolyte exchange in Amoeba proteus].

    Science.gov (United States)

    Bagrov, Ia Iu; Manusova, N B

    2014-01-01

    Dopamine and adenosine both regulate transport of sodium chloride in the renal tubules in mammals. We have studied the effect of dopamine and adenosine on spontaneous activity of contractile vacuole of Amoeba proteous. Both substances stimulated contractile vacuole. The effect of dopamine was suppressed by D2 receptor antagonist, haloperidol, but not by D1 antagonist, SCH 39166. Adenylate cyclase inhibitor, 2.5-dideoxyadenosine, suppressed the effect of dopamine, but not of adenosine. Inhibitor of protein kinase C, staurosporine, in contrast, blocked the effect of adenosine, but not dopamine. Notably, dopamine opposed effect of adenosine and vice versa. These results suggest that similar effects of dopamine and adenosine could be mediated by different intracellulare mechanisms.

  3. Acute hyperammonemia and systemic inflammation is associated with increased extracellular brain adenosine in rats

    DEFF Research Database (Denmark)

    Bjerring, Peter Nissen; Dale, Nicholas; Larsen, Fin Stolze

    2015-01-01

    Acute liver failure (ALF) can lead to brain edema, cerebral hyperperfusion and intracranial hypertension. These complications are thought to be mediated by hyperammonemia and inflammation leading to altered brain metabolism. As increased levels of adenosine degradation products have been found...... in brain tissue of patients with ALF we investigated whether hyperammonemia could induce adenosine release in brain tissue. Since adenosine is a potent vasodilator and modulator of cerebral metabolism we furthermore studied the effect of adenosine receptor ligands on intracranial pressure (ICP......) and cerebral blood flow (CBF). We measured the adenosine concentration with biosensors in rat brain slices exposed to ammonia and in a rat model with hyperammonemia and systemic inflammation. Exposure to ammonia in concentrations from 0.15-10 mM led to increases in the cortical adenosine concentration up to 18...

  4. Contraction induced secretion of VEGF from skeletal muscle cells is mediated by adenosine

    DEFF Research Database (Denmark)

    Høier, Birgitte; Olsen, Karina; Nyberg, Michael Permin;

    2010-01-01

    The role of adenosine and contraction for secretion of VEGF in skeletal muscle was investigated in human subjects and rat primary skeletal muscle cells. Microdialysis probes were inserted into the thigh muscle of seven male subjects and dialysate was collected at rest, during infusion of adenosine...... and contraction caused secretion of VEGF (pcontraction induced secretion of VEGF protein was abolished by the A(2B) antagonist enprofyllin and markedly reduced by inhibition of PKA or MAPK. The results demonstrate that adenosine causes secretion of VEGF from human skeletal muscle cells...... and that the contraction induced secretion of VEGF is partially mediated via adenosine acting on A(2B) adenosine receptors. Moreover, the contraction induced secretion of VEGF protein from muscle is dependent on both PKA and MAPK activation, but only the MAPK pathway appears to be adenosine dependent....

  5. A sensitive LC-MS/MS method for quantifying clofarabine triphosphate concentrations in human peripheral blood mononuclear cells.

    Science.gov (United States)

    Tu, Xiaowei; Lu, Youming; Zhong, Dafang; Zhang, Yifan; Chen, Xiaoyan

    2014-08-01

    Clofarabine triphosphate is an intracellular active metabolite of clofarabine. In the present study, we developed and validated a rapid, sensitive, and selective liquid chromatography-tandem mass spectrometry method (LC-MS/MS) for quantifying clofarabine triphosphate concentrations in human peripheral blood mononuclear cells (PBMCs). PBMCs were isolated from blood using the Ficoll gradient centrifugation method. Chromatographic separation was performed on a CN column using an isocratic mobile phase comprising acetonitrile/5mM ammonium acetate with 0.001% ammonium hydroxide (20/80, v/v) at a flow rate of 0.60 mL/min. Detection was carried out by MS/MS in the multiple reaction monitoring mode using a negative electrospray ionization interface. The method was validated in concentration ranges of 1.25-100 ng/10(7) cells with acceptable accuracy and precision using 50 μL of cell extract. Clofarabine triphosphate was stable in a series of stability studies with bench-top, auto-sampler, and repeated freeze-thaw cycles. The validated method was successfully used to measure the concentrations of clofarabine triphosphate in PBMCs from cancer patients treated with clofarabine. PMID:24529342

  6. Topical adenosine increases the proportion of thick hair in Caucasian men with androgenetic alopecia.

    Science.gov (United States)

    Iwabuchi, Tokuro; Ideta, Ritsuro; Ehama, Ritsuko; Yamanishi, Haruyo; Iino, Masato; Nakazawa, Yosuke; Kobayashi, Takashi; Ohyama, Manabu; Kishimoto, Jiro

    2016-05-01

    Adenosine is an effective treatment for androgenetic alopecia (AGA) in Japanese men and women. Adenosine exerts its effects by significantly increasing the proportion of thick hair. In this study, we assessed the clinical outcome of adenosine treatment for 6 months in 38 Caucasian men. The change in proportion of thick hair (≥60 μm) compared with baseline in the adenosine group was significantly higher than that in the placebo group (P thick hair in Caucasian men with AGA as well as in Japanese men and women.

  7. Structure of the nucleotide-binding subunit B of the energy producer A1A0 ATP synthase in complex with adenosine diphosphate.

    Science.gov (United States)

    Kumar, Anil; Manimekalai, Malathy Sony Subramanian; Grüber, Gerhard

    2008-11-01

    A1A0 ATP synthases are the major energy producers in archaea. Like the related prokaryotic and eukaryotic F1F0 ATP synthases, they are responsible for most of the synthesis of adenosine triphosphate. The catalytic events of A1A0 ATP synthases take place inside the A3B3 hexamer of the A1 domain. Recently, the crystallographic structure of the nucleotide-free subunit B of Methanosarcina mazei Gö1 A1A0 ATP synthase has been determined at 1.5 A resolution. To understand more about the nucleotide-binding mechanism, a protocol has been developed to crystallize the subunit B-ADP complex. The crystallographic structure of this complex has been solved at 2.7 A resolution. The ADP occupies a position between the essential phosphate-binding loop and amino-acid residue Phe149, which are involved in the binding of the antibiotic efrapeptin in the related F1F0 ATP synthases. This trapped ADP location is about 13 A distant from its final binding site and is therefore called the transition ADP-binding position. In the trapped ADP position the structure of subunit B adopts a different conformation, mainly in its C-terminal domain and also in the final nucleotide-binding site of the central alphabeta-domain. This atomic model provides insight into how the substrate enters into the nucleotide-binding protein and thereby into the catalytic A3B3 domain. PMID:19020348

  8. Adenosine diphosphate ribosylation of dinitrogenase reductase and adenylylation of glutamine synthetase control ammonia excretion in ethylenediamine-resistant mutants of Azospirillum brasilense Sp7.

    Science.gov (United States)

    Srivastava, A; Tripathi, A K

    2006-10-01

    Azospirillum brasilense is a nitrogen-fixing, root-colonizing bacterium that brings about plant-growth-promoting effects mainly because of its ability to produce phytohormones. Ethylenediamine (EDA)-resistant mutants of A. brasilense were isolated and screened for their higher ability to decrease acetylene and release ammonia in the medium. One of the mutants showed considerably higher levels of acetylene decrease and ammonia excretion. Nitrogenase activity of this mutant was relatively resistant to inhibition by NH(4)Cl. Adenosine triphosphate ribosylation of dinitrogenase reductase in the mutant did not increase even in presence of 10 mM NH(4)Cl. Although the mutant showed decreased glutamine synthetase (GS) activity, neither the levels of GS synthesized by the mutant nor the NH (4) (+) -binding site in the GS differed from those of the parent. The main reason for the release of ammonia by the mutant seems to be the fixation of higher levels of nitrogen than its GS can assimilate, as well as higher levels of adenylylation of GS, which may decrease ammonia assimilation.

  9. Genetically Controlled Upregulation of Adenosine A(1) Receptor Expression Enhances the Survival of Primary Cortical Neurons

    NARCIS (Netherlands)

    Serchov, Tsvetan; Atas, Hasan-Cem; Normann, Claus; van Calker, Dietrich; Biber, Knut

    2012-01-01

    Adenosine has a key endogenous neuroprotective role in the brain, predominantly mediated by the adenosine A(1) receptor (A(1)R). This has been mainly explored using pharmacological tools and/or receptor knockout mice strains. It has long been suggested that the neuroprotective effects of A(1)R are i

  10. Activation of A(2) adenosine receptors dilates cortical efferent arterioles in mouse

    DEFF Research Database (Denmark)

    Al-Mashhadi, Rozh H; Skøtt, Ole; Vanhoutte, Paul M;

    2009-01-01

    that the adenosine-induced vasodilatation was inhibited by the A(2)-specific receptor blocker 3,7-dimethyl-1-propargylxanthine. In the presence of this inhibitor, adenosine failed to alter the basal vessel diameter of quiescent efferent arterioles. Using primer-specific polymerase chain reaction we found...

  11. Adenosine receptors in COPD and asymptomatic smokers : effects of smoking cessation

    NARCIS (Netherlands)

    Versluis, Mieke; ten Hacken, Nick; Postma, Dirkje; Barroso, Begona; Rutgers, Bea; Geerlings, Marie; Willemse, Brigitte; Timens, Wim; Hylkema, Machteld

    2009-01-01

    Our group has shown that 1-year smoking cessation persisted or increased airway inflammation in chronic obstructive pulmonary disease (COPD). We compared adenosine and adenosine receptor (AR) expression in COPD and asymptomatic smokers (AS) before and after 1-year smoking cessation. Sputum cytospins

  12. Role of adenosine in regulating the heterogeneity of skeletal muscle blood flow during exercise in humans

    DEFF Research Database (Denmark)

    Heinonen, Ilkka; Nesterov, Sergey V; Kemppainen, Jukka;

    2007-01-01

    Evidence from both animal and human studies suggests that adenosine plays a role in the regulation of exercise hyperemia in skeletal muscle. We tested whether adenosine also plays a role in the regulation of blood flow (BF) distribution and heterogeneity among and within quadriceps femoris (QF...

  13. Adenosine signaling and the energetic costs of induced immunity.

    Directory of Open Access Journals (Sweden)

    Brian P Lazzaro

    2015-04-01

    Full Text Available Life history theory predicts that trait evolution should be constrained by competing physiological demands on an organism. Immune defense provides a classic example in which immune responses are presumed to be costly and therefore come at the expense of other traits related to fitness. One strategy for mitigating the costs of expensive traits is to render them inducible, such that the cost is paid only when the trait is utilized. In the current issue of PLOS Biology, Bajgar and colleagues elegantly demonstrate the energetic and life history cost of the immune response that Drosophila melanogaster larvae induce after infection by the parasitoid wasp Leptopilina boulardi. These authors show that infection-induced proliferation of defensive blood cells commands a diversion of dietary carbon away from somatic growth and development, with simple sugars instead being shunted to the hematopoetic organ for rapid conversion into the raw energy required for cell proliferation. This metabolic shift results in a 15% delay in the development of the infected larva and is mediated by adenosine signaling between the hematopoietic organ and the central metabolic control organ of the host fly. The adenosine signal thus allows D. melanogaster to rapidly marshal the energy needed for effective defense and to pay the cost of immunity only when infected.

  14. Adenosine Amine Congener as a Cochlear Rescue Agent

    Directory of Open Access Journals (Sweden)

    Srdjan M. Vlajkovic

    2014-01-01

    Full Text Available We have previously shown that adenosine amine congener (ADAC, a selective A1 adenosine receptor agonist, can ameliorate noise- and cisplatin-induced cochlear injury. Here we demonstrate the dose-dependent rescue effects of ADAC on noise-induced cochlear injury in a rat model and establish the time window for treatment. Methods. ADAC (25–300 μg/kg was administered intraperitoneally to Wistar rats (8–10 weeks old at intervals (6–72 hours after exposure to traumatic noise (8–16 kHz, 110 dB sound pressure level, 2 hours. Hearing sensitivity was assessed using auditory brainstem responses (ABR before and 12 days after noise exposure. Pharmacokinetic studies investigated ADAC concentrations in plasma after systemic (intravenous administration. Results. ADAC was most effective in the first 24 hours after noise exposure at doses >50 μg/kg, providing up to 21 dB protection (averaged across 8–28 kHz. Pharmacokinetic studies demonstrated a short (5 min half-life of ADAC in plasma after intravenous administration without detection of degradation products. Conclusion. Our data show that ADAC mitigates noise-induced hearing loss in a dose- and time-dependent manner, but further studies are required to establish its translation as a clinical otological treatment.

  15. Novel trypanocidal analogs of 5'-(methylthio)-adenosine.

    Science.gov (United States)

    Sufrin, Janice R; Spiess, Arthur J; Marasco, Canio J; Rattendi, Donna; Bacchi, Cyrus J

    2008-01-01

    The purine nucleoside 5'-deoxy-5'-(hydroxyethylthio)-adenosine (HETA) is an analog of the polyamine pathway metabolite 5'-deoxy-5'-(methylthio)-adenosine (MTA). HETA is a lead structure for the ongoing development of selectively targeted trypanocidal agents. Thirteen novel HETA analogs were synthesized and examined for their in vitro trypanocidal activities against bloodstream forms of Trypanosoma brucei brucei LAB 110 EATRO and at least one drug-resistant Trypanosoma brucei rhodesiense clinical isolate. New compounds were also assessed in a cell-free assay for their activities as substrates of trypanosome MTA phosphorylase. The most potent analog in this group was 5'-deoxy-5'-(hydroxyethylthio)-tubercidin, whose in vitro cytotoxicity (50% inhibitory concentration [IC50], 10 nM) is 45 times greater than that of HETA (IC50, 450 nM) against pentamidine-resistant clinical isolate KETRI 269. Structure-activity analyses indicate that the enzymatic cleavage of HETA analogs by trypanosome MTA phosphorylase is not an absolute requirement for trypanocidal activity. This suggests that additional biochemical mechanisms are associated with the trypanocidal effects of HETA and its analogs.

  16. Distribution of adenosine receptors in human sclera fibroblasts

    Science.gov (United States)

    Cui, Dongmei; Trier, Klaus; Chen, Xiang; Zeng, Junwen; Yang, Xiao; Hu, Jianmin

    2008-01-01

    Purpose Systemic treatment with adenosine receptor antagonists has been reported to affect the biochemistry and ultrastructure of rabbit sclera. This study was conducted to determine whether adenosine receptors (ADORs) are present in human scleral fibroblasts (HSF). Methods Primary HSF were cultured in vitro and identified with anti-vimentin, anti-keratin, anti-desmin, and anti-S-100 antibodies. Confocal fluorescence microscopy was used to study the distribution of ADORs in the HSF cell lines and in the frozen human scleral sections. ADOR protein expression in HSF and human sclera was confirmed by western blot analysis of cell lysates. Results ADORs were expressed in both HSF and human sclera. This was confirmed by western blot. ADORA1 expression was concentrated in the nucleus. ADORA2A was concentrated mainly in one side of the cytoplasm, and ADORA2B was found both in the nucleus and the cytoplasm. ADORA3 was expressed weakly in the cytoplasm. Conclusions All four subtypes of ADOR were found in HSF and may play a role in scleral remodeling. PMID:18385786

  17. Feed-Forward Inhibition of CD73 and Upregulation of Adenosine Deaminase Contribute to the Loss of Adenosine Neuromodulation in Postinflammatory Ileitis

    OpenAIRE

    Cátia Vieira; Maria Teresa Magalhães-Cardoso; Fátima Ferreirinha; Isabel Silva; Ana Sofia Dias; Julie Pelletier; Jean Sévigny; Paulo Correia-de-Sá

    2014-01-01

    Purinergic signalling is remarkably plastic during gastrointestinal inflammation. Thus, selective drugs targeting the “purinome” may be helpful for inflammatory gastrointestinal diseases. The myenteric neuromuscular transmission of healthy individuals is fine-tuned and controlled by adenosine acting on A2A excitatory receptors. Here, we investigated the neuromodulatory role of adenosine in TNBS-inflamed longitudinal muscle-myenteric plexus of the rat ileum. Seven-day postinflammation ileitis ...

  18. Cloning, expression and pharmacological characterization of rabbit adenosine A1 and A3 receptors.

    Science.gov (United States)

    Hill, R J; Oleynek, J J; Hoth, C F; Kiron, M A; Weng, W; Wester, R T; Tracey, W R; Knight, D R; Buchholz, R A; Kennedy, S P

    1997-01-01

    The role of adenosine A1 and A3 receptors in mediating cardioprotection has been studied predominantly in rabbits, yet the pharmacological characteristics of rabbit adenosine A1 and A3 receptor subtypes are unknown. Thus, the rabbit adenosine A3 receptor was cloned and expressed, and its pharmacology was compared with that of cloned adenosine A1 receptors. Stable transfection of rabbit A1 or A3 cDNAs in Chinese hamster ovary-K1 cells resulted in high levels of expression of each of the receptors, as demonstrated by high-affinity binding of the A1/A3 adenosine receptor agonist N6-(4-amino-3-[125I]iodobenzyl)adenosine (125I-ABA). For both receptors, binding of 125I-ABA was inhibited by the GTP analog 5'-guanylimidodiphosphate, and forskolin-stimulated cyclic AMP accumulation was inhibited by the adenosine receptor agonist (R)-phenylisopropyladenosine. The rank orders of potency of adenosine receptor agonists for inhibition of 125I-ABA binding were as follows: rabbit A1, N6-cyclopentyladenosine = (R)-phenylisopropyladenosine > N-ethylcarboxamidoadenosine > or = I-ABA > or = N6-2-(4-aminophenyl) ethyladenosine > > N6-(3-iodobenzyl)adenosine-5'-N-methyluronamide > N6-(4-amino-3-benzyl)adenosine; rabbit A3, N6-(3-iodobenzyl)adenosine-5'-N-methyluronamide > or = I-ABA > > N-ethylcarboxamidoadenosine > N6-2-(4-aminophenyl) ethyladenosine = N6-cyclopentyladenosine = (R)-phenylisopropyladenosine > N6-(4-amino-3-benzyl)adenosine. The adenosine receptor antagonist rank orders were as follow: rabbit A1, 8-cyclopentyl-1,3-dipropylxanthine > 1,3- dipropyl-8-(4-acrylate)phenylxanthine > or = xanthine amine congener > > 8-(p-sulfophenyl)theophylline; rabbit A3, xanthine amine congener > 1,3-dipropyl-8-(4-acrylate)phenylxanthine > or = 8-cyclopentyl-1,3-dipropylxanthine > > 8-(p-sulfophenyl)theophylline. These observations confirm the identity of the expressed proteins as A1 and A3 receptors. The results will facilitate further in-depth studies of the roles of A1 and A3 receptors in

  19. Distinct Roles for the A2B Adenosine Receptor in Acute and Chronic Stages of Bleomycin-Induced Lung Injury

    OpenAIRE

    Yang ZHOU; Schneider, Daniel J.; Morschl, Eva; Song, Ling; Pedroza, Mesias; Karmouty-Quintana, Harry; Le, Thuy.; Sun, Chun-Xiao; Blackburn, Michael R.

    2010-01-01

    Adenosine is an extracellular signaling molecule that is generated in response to cell injury where it orchestrates tissue protection and repair. Whereas adenosine is best known for promoting anti-inflammatory activities during acute injury responses, prolonged elevations can enhance destructive tissue remodeling processes associated with chronic disease states. The generation of adenosine and the subsequent activation of the adenosine 2B receptor (A2BR) is an important processes in the regul...

  20. Reconstruction of the adenosine system by bone marrow-derived mesenchymal stem cell transplantation

    Institute of Scientific and Technical Information of China (English)

    Huicong Kang; Qi Hu; Xiaoyan Liu; Yinhe Liu; Feng Xu; Xiang Li; Suiqiang Zhu

    2012-01-01

    In the present study, we transplanted bone marrow-derived mesenchymal stem cells into the CA3 area of the hippocampus of chronic epilepsy rats kindled by lithium chloride-pilocarpine. Immunofluorescence and western blotting revealed an increase in adenosine A1 receptor expression and a decrease in adenosine A2a receptor expression in the brain tissues of epileptic rats 3 months after transplantation. Moreover, the imbalance in the A1 adenosine receptor/A2a adenosine receptor ratio was improved. Electroencephalograms showed that frequency and amplitude of spikes in the hippocampus and frontal lobe were reduced. These results suggested that mesenchymal stem cell transplantation can reconstruct the normal function of the adenosine system in the brain and greatly improve epileptiform discharges.

  1. Comparison of exogenous adenosine and voluntary exercise on human skeletal muscle perfusion and perfusion heterogeneity

    DEFF Research Database (Denmark)

    Heinonen, Ilkka H.A.; Kemppainen, Jukka; Kaskinoro, Kimmo;

    2010-01-01

    Adenosine is a widely used pharmacological agent to induce a 'high flow' control condition to study the mechanisms of exercise hyperemia, but it is not known how well adenosine infusion depicts exercise-induced hyperemia especially in terms of blood flow distribution at the capillary level in human...... muscle. Additionally, it remains to be determined what proportion of adenosine-induced flow elevation is specifically directed to muscle only. In the present study we measured thigh muscle capillary nutritive blood flow in nine healthy young men using positron emission tomography at rest and during...... femoral artery infusion of adenosine (1 mg * min(-1) * litre thigh volume(-1)), which has previously been shown to induce maximal whole thigh blood flow of ~8 L/min. This response was compared to the blood flow induced by moderate-high intensity one-leg dynamic knee extension exercise. Adenosine increased...

  2. Adenosine stimulates DNA fragmentation in human thymocytes by Ca(2+)-mediated mechanisms.

    Science.gov (United States)

    Szondy, Z

    1994-12-15

    Incubation of human thymocytes with an optimum concentration of adenosine and its receptor site agonist, 2-chloroadenosine, induced increases in intracellular cyclic AMP (cAMP) (from a resting 0.6 +/- 0.1 to 4.1 +/- 0.2 pmol/10(7) cells within 5 min) and Ca2+ (from the resting 85 +/- 7 nM to a peak of 210 +/- 25 nM) levels and resulted in internucleosomal DNA fragmentation and cell death (apoptosis). Other adenosine analogues were also effective at inducing DNA fragmentation, the order of potency being 2-p-(carboxyethylphenylethylamino)-5'-carboxyamidoadenosine 13399-13402], at 60 ng/ml concentration also prevented adenosine-induced DNA fragmentation when added prior to adenosine. This suggested a complex cross-talk between the adenosine-triggered signal transduction cascade and the activation state of protein kinase C in regulating apoptosis of human thymocytes. PMID:7818494

  3. Adenosine formation in contracting primary rat skeletal muscle cells and endothelial cells in culture

    DEFF Research Database (Denmark)

    Hellsten, Ylva; Frandsen, Ulrik

    1997-01-01

    in the extracellular adenosine concentration (421 +/- 91 and 235 +/- 30 nmol (g protein)-1, respectively; P muscle cells (161 +/- 20 nmol (g protein)-1). The ATP concentration was lower (18%; P muscle cells...... found to have ecto-forms of several enzymes involved in nucleotide metabolism, including ATPases capable of converting extracellular ATP to ADP and AMP. 5. Adenosine added to the cell medium was taken up by muscle cells and incorporated into the adenine nucleotide pool so that after 30 min of incubation......, over 95% of the adenosine label was present in ATP, ADP and AMP. A similar extent of incorporation of adenosine into the nucleotide pool was evident in the endothelial cells. 6. The present data suggest that contracting muscle cells induce an elevation in the extracellular adenosine concentration...

  4. 2-(1-Hexyn-1-yl)adenosine-induced intraocular hypertension is mediated via K+ channel opening through adenosine A2A receptor in rabbits.

    Science.gov (United States)

    Konno, Takashi; Uchibori, Takehiro; Nagai, Akihiko; Kogi, Kentaro; Nakahata, Norimichi

    2005-08-22

    The present study was performed to clarify the mechanism of change in intraocular pressure by 2-(1-hexyn-1-yl)adenosine (2-H-Ado), a selective adenosine A2 receptor agonist, in rabbits. 2-H-Ado (0.1%, 50 microl)-induced ocular hypertension (E(max): 7.7 mm Hg) was inhibited by an adenosine A2A receptor antagonist 1,3,7-trimethyl-8-(3-chlorostyryl)xanthine, ATP-sensitive K+ channel blocker glibenclamide or 5-hydroxydecanoic acid, but not by an adenosine A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine, an adenosine A2B receptor antagonist alloxazine or a cyclooxygenase inhibitor indomethacin. The outflow facility induced by 2-H-Ado seems to be independent of increase in intraocular pressure or ATP-sensitive K+ channel. In contrast, the recovery rate in intraocular pressure decreased by hypertonic saline was accelerated by 2-H-Ado, and this response was dependent on ATP-sensitive K+ channel. These results suggest that 2-H-Ado-induced ocular hypertension is mediated via K+ channel opening through adenosine A2A receptor, and this is probably due to aqueous formation, but independent of change in outflow facility or prostaglandin production.

  5. 2-(1-Hexyn-1-yl)adenosine-induced intraocular hypertension is mediated via K+ channel opening through adenosine A2A receptor in rabbits.

    Science.gov (United States)

    Konno, Takashi; Uchibori, Takehiro; Nagai, Akihiko; Kogi, Kentaro; Nakahata, Norimichi

    2005-08-22

    The present study was performed to clarify the mechanism of change in intraocular pressure by 2-(1-hexyn-1-yl)adenosine (2-H-Ado), a selective adenosine A2 receptor agonist, in rabbits. 2-H-Ado (0.1%, 50 microl)-induced ocular hypertension (E(max): 7.7 mm Hg) was inhibited by an adenosine A2A receptor antagonist 1,3,7-trimethyl-8-(3-chlorostyryl)xanthine, ATP-sensitive K+ channel blocker glibenclamide or 5-hydroxydecanoic acid, but not by an adenosine A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine, an adenosine A2B receptor antagonist alloxazine or a cyclooxygenase inhibitor indomethacin. The outflow facility induced by 2-H-Ado seems to be independent of increase in intraocular pressure or ATP-sensitive K+ channel. In contrast, the recovery rate in intraocular pressure decreased by hypertonic saline was accelerated by 2-H-Ado, and this response was dependent on ATP-sensitive K+ channel. These results suggest that 2-H-Ado-induced ocular hypertension is mediated via K+ channel opening through adenosine A2A receptor, and this is probably due to aqueous formation, but independent of change in outflow facility or prostaglandin production. PMID:16023100

  6. Age-associated repression of type 1 inositol 1, 4, 5-triphosphate receptor impairs muscle regeneration

    Science.gov (United States)

    Lee, Bora; Lee, Seung-Min; Bahn, Young Jae; Lee, Kwang-Pyo; Kang, Moonkyung; Kim, Yeon-Soo; Woo, Sun-Hee; Lim, Jae-Young; Kim, Eunhee; Kwon, Ki-Sun

    2016-01-01

    Skeletal muscle mass and power decrease with age, leading to impairment of mobility and metabolism in the elderly. Ca2+ signaling is crucial for myoblast differentiation as well as muscle contraction through activation of transcription factors and Ca2+-dependent kinases and phosphatases. Ca2+ channels, such as dihydropyridine receptor (DHPR), two-pore channel (TPC) and inositol 1,4,5-triphosphate receptor (ITPR), function to maintain Ca2+ homeostasis in myoblasts. Here, we observed a significant decrease in expression of type 1 IP3 receptor (ITPR1), but not types 2 and 3, in aged mice skeletal muscle and isolated myoblasts, compared with those of young mice. ITPR1 knockdown using shRNA-expressing viruses in C2C12 myoblasts and tibialis anterior muscle of mice inhibited myotube formation and muscle regeneration after injury, respectively, a typical phenotype of aged muscle. This aging phenotype was associated with repression of muscle-specific genes and activation of the epidermal growth factor receptor (EGFR)-Ras-extracellular signal-regulated kinase (ERK) pathway. ERK inhibition by U0126 not only induced recovery of myotube formation in old myoblasts but also facilitated muscle regeneration after injury in aged muscle. The conserved decline in ITPR1 expression in aged human skeletal muscle suggests utility as a potential therapeutic target for sarcopenia, which can be treated using ERK inhibition strategies. PMID:27658230

  7. Involvement of adenosine A2a receptor in intraocular pressure decrease induced by 2-(1-octyn-1-yl)adenosine or 2-(6-cyano-1-hexyn-1-yl)adenosine.

    Science.gov (United States)

    Konno, Takashi; Murakami, Akira; Uchibori, Takehiro; Nagai, Akihiko; Kogi, Kentaro; Nakahata, Norimichi

    2005-04-01

    The aim of the present study is to clarify the mechanism for the decrease in intraocular pressure by 2-alkynyladenosine derivatives in rabbits. The receptor binding analysis revealed that 2-(1-octyn-1-yl)adenosine (2-O-Ado) and 2-(6-cyano-1-hexyn-1-yl)adenosine (2-CN-Ado) selectively bound to the A(2a) receptor with a high affinity. Ocular hypotensive responses to 2-O-Ado and 2-CN-Ado were inhibited by the adenosine A(2a)-receptor antagonist 1,3,7-trimethyl-8-(3-chlorostyryl)xanthine (CSC), but not by the adenosine A(1)-receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) or the adenosine A(2b)-receptor antagonist alloxazine. In addition, 2-O-Ado and 2-CN-Ado caused an increase in outflow facility, which was inhibited by CSC, but not by DPCPX or alloxazine. Moreover, 2-O-Ado and 2-CN-Ado increased cAMP in the aqueous humor, and the 2-O-Ado-induced an increase in cAMP was inhibited by CSC. These results suggest that 2-O-Ado and 2-CN-Ado reduced intraocular pressure via an increase in outflow facility. The ocular hypotension may be mainly mediated through the activation of adenosine A(2a) receptor, although a possible involvement of adenosine A(1) receptor cannot be completely ruled out. 2-O-Ado and 2-CN-Ado are useful lead compounds for the treatment of glaucoma.

  8. Involvement of adenosine A2a receptor in intraocular pressure decrease induced by 2-(1-octyn-1-yl)adenosine or 2-(6-cyano-1-hexyn-1-yl)adenosine.

    Science.gov (United States)

    Konno, Takashi; Murakami, Akira; Uchibori, Takehiro; Nagai, Akihiko; Kogi, Kentaro; Nakahata, Norimichi

    2005-04-01

    The aim of the present study is to clarify the mechanism for the decrease in intraocular pressure by 2-alkynyladenosine derivatives in rabbits. The receptor binding analysis revealed that 2-(1-octyn-1-yl)adenosine (2-O-Ado) and 2-(6-cyano-1-hexyn-1-yl)adenosine (2-CN-Ado) selectively bound to the A(2a) receptor with a high affinity. Ocular hypotensive responses to 2-O-Ado and 2-CN-Ado were inhibited by the adenosine A(2a)-receptor antagonist 1,3,7-trimethyl-8-(3-chlorostyryl)xanthine (CSC), but not by the adenosine A(1)-receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) or the adenosine A(2b)-receptor antagonist alloxazine. In addition, 2-O-Ado and 2-CN-Ado caused an increase in outflow facility, which was inhibited by CSC, but not by DPCPX or alloxazine. Moreover, 2-O-Ado and 2-CN-Ado increased cAMP in the aqueous humor, and the 2-O-Ado-induced an increase in cAMP was inhibited by CSC. These results suggest that 2-O-Ado and 2-CN-Ado reduced intraocular pressure via an increase in outflow facility. The ocular hypotension may be mainly mediated through the activation of adenosine A(2a) receptor, although a possible involvement of adenosine A(1) receptor cannot be completely ruled out. 2-O-Ado and 2-CN-Ado are useful lead compounds for the treatment of glaucoma. PMID:15821340

  9. Real-time monitoring of extracellular adenosine using enzyme-linked microelectrode arrays.

    Science.gov (United States)

    Hinzman, Jason M; Gibson, Justin L; Tackla, Ryan D; Costello, Mark S; Burmeister, Jason J; Quintero, Jorge E; Gerhardt, Greg A; Hartings, Jed A

    2015-12-15

    Throughout the central nervous system extracellular adenosine serves important neuroprotective and neuromodulatory functions. However, current understanding of the in vivo regulation and effects of adenosine is limited by the spatial and temporal resolution of available measurement techniques. Here, we describe an enzyme-linked microelectrode array (MEA) with high spatial (7500 µm(2)) and temporal (4 Hz) resolution that can selectively measure extracellular adenosine through the use of self-referenced coating scheme that accounts for interfering substances and the enzymatic breakdown products of adenosine. In vitro, the MEAs selectively measured adenosine in a linear fashion (r(2)=0.98±0.01, concentration range=0-15 µM, limit of detection =0.96±0.5 µM). In vivo the limit of detection was 0.04±0.02 µM, which permitted real-time monitoring of the basal extracellular concentration in rat cerebral cortex (4.3±1.5 µM). Local cortical injection of adenosine through a micropipette produced dose-dependent transient increases in the measured extracellular concentration (200 nL: 6.8±1.8 µM; 400 nL: 19.4±5.3 µM) [P<0.001]. Lastly, local injection of dipyridamole, which inhibits transport of adenosine through equilibrative nucleoside transporter, raised the measured extracellular concentration of adenosine by 120% (5.6→12.3 µM) [P<0.001]. These studies demonstrate that MEAs can selectively measure adenosine on temporal and spatial scales relevant to adenosine signaling and regulation in normal and pathologic states. PMID:26183072

  10. Specificity of synergistic coronary flow enhancement by adenosine and pulsatile perfusion in the dog.

    Science.gov (United States)

    Pagliaro, P; Senzaki, H; Paolocci, N; Isoda, T; Sunagawa, G; Recchia, F A; Kass, D A

    1999-10-01

    1. Coronary flow elevation from enhanced perfusion pulsatility is synergistically amplified by adenosine. This study determined the specificity of this interaction and its potential mechanisms. 2. Mean and phasic coronary flow responses to increasing pulsatile perfusion were assessed in anaesthetized dogs, with the anterior descending coronary artery servoperfused to regulate real-time physiological flow pulsatility at constant mean pressure. Pulsatility was varied between 40 and 100 mmHg. Hearts ejected into the native aorta whilst maintaining stable loading. 3. Increasing pulsatility elevated mean coronary flow +11.5 +/- 1.7 % under basal conditions. Co-infusion of adenosine sufficient to raise baseline flow 66 % markedly amplified this pulsatile perfusion response (+82. 6 +/- 14.3 % increase in mean flow above adenosine baseline), due to a leftward shift of the adenosine-coronary flow response curve at higher pulsatility. Flow augmentation with pulsatility was not linked to higher regional oxygen consumption, supporting direct rather than metabolically driven mechanisms. 4. Neither bradykinin, acetylcholine nor verapamil reproduced the synergistic amplification of mean flow by adenosine and higher pulsatility, despite being administered at doses matching basal flow change with adenosine. 5. ATP-sensitive potassium (KATP) activation (pinacidil) amplified the pulse-flow response 3-fold, although this remained significantly less than with adenosine. Co-administration of the phospholipase A2 inhibitor quinacrine virtually eliminated adenosine-induced vasodilatation, yet synergistic interaction between adenosine and pulse perfusion persisted, albeit at a reduced level. 6. Thus, adenosine and perfusion pulsatility specifically interact to enhance coronary flow. This synergy is partially explained by KATP agonist action and additional non-flow-dependent mechanisms, and may be important for modulating flow reserve during exercise or other high output states where

  11. Overexpression, purification and crystallographic analysis of a unique adenosine kinase from Mycobacterium tuberculosis

    International Nuclear Information System (INIS)

    Adenosine kinase from M. tuberculosis has been overexpressed, purified and crystallized in the presence of adenosine. Structure determination using molecular replacement with diffraction data collected at 2.2 Å reveals a dimeric structure. Adenosine kinase from Mycobacterium tuberculosis is the only prokaryotic adenosine kinase that has been isolated and characterized. The enzyme catalyzes the phosphorylation of adenosine to adenosine monophosphate and is involved in the activation of 2-methyladenosine, a compound that has demonstrated selective activity against M. tuberculosis. The mechanism of action of 2-methyladenosine is likely to be different from those of current tuberculosis treatments and this compound (or other adenosine analogs) may prove to be a novel therapeutic intervention for this disease. The M. tuberculosis adenosine kinase was overexpressed in Escherichia coli and the enzyme was purified with activity comparable to that reported previously. The protein was crystallized in the presence of adenosine using the vapour-diffusion method. The crystals diffracted X-rays to high resolution and a complete data set was collected to 2.2 Å using synchrotron radiation. The crystal belonged to space group P3121, with unit-cell parameters a = 70.2, c = 111.6 Å, and contained a single protein molecule in the asymmetric unit. An initial structural model of the protein was obtained by the molecular-replacement method, which revealed a dimeric structure. The monomers of the dimer were related by twofold crystallographic symmetry. An understanding of how the M. tuberculosis adenosine kinase differs from the human homolog should aid in the design of more potent and selective antimycobacterial agents that are selectively activated by this enzyme

  12. Identification of an Alternative Nucleoside Triphosphate: 5′-Deoxyadenosylcobinamide Phosphate Nucleotidyltransferase in Methanobacterium thermoautotrophicum ΔH

    OpenAIRE

    Michael G Thomas; Escalante-Semerena, Jorge C.

    2000-01-01

    Computer analysis of the archaeal genome databases failed to identify orthologues of all of the bacterial cobamide biosynthetic enzymes. Of particular interest was the lack of an orthologue of the bifunctional nucleoside triphosphate (NTP):5′-deoxyadenosylcobinamide kinase/GTP:adenosylcobinamide-phosphate guanylyltransferase enzyme (CobU in Salmonella enterica). This paper reports the identification of an archaeal gene encoding a new nucleotidyltransferase, which is proposed to be the nonorth...

  13. HPLC–MS/MS method for the intracellular determination of ribavirin monophosphate and ribavirin triphosphate in CEMss cells

    OpenAIRE

    Meléndez, Margarita; Rosario, Osvaldo; Zayas, Beatriz; Rodríguez, José F.

    2009-01-01

    A sensitive and specific method using high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) for the determination of ribavirin monophosphate (RBV-MP) and ribavirin triphosphate (RBV-TP) in cells has been developed and validated. In this method, ribavirin phosphorylated metabolites were extracted and separated by anion exchange solid phase extraction (SPE). The RBV-MP and RBV-TP fractions were dephosphorylated using acid phosphatase and further purified by phenyl boronat...

  14. Assays To Detect the Formation of Triphosphates of Unnatural Nucleotides: Application to Escherichia coli Nucleoside Diphosphate Kinase.

    Science.gov (United States)

    Matsuura, Mariko F; Shaw, Ryan W; Moses, Jennifer D; Kim, Hyo-Joong; Kim, Myong-Jung; Kim, Myong-Sang; Hoshika, Shuichi; Karalkar, Nilesh; Benner, Steven A

    2016-03-18

    One frontier in synthetic biology seeks to move artificially expanded genetic information systems (AEGIS) into natural living cells and to arrange the metabolism of those cells to allow them to replicate plasmids built from these unnatural genetic systems. In addition to requiring polymerases that replicate AEGIS oligonucleotides, such cells require metabolic pathways that biosynthesize the triphosphates of AEGIS nucleosides, the substrates for those polymerases. Such pathways generally require nucleoside and nucleotide kinases to phosphorylate AEGIS nucleosides and nucleotides on the path to these triphosphates. Thus, constructing such pathways focuses on engineering natural nucleoside and nucleotide kinases, which often do not accept the unnatural AEGIS biosynthetic intermediates. This, in turn, requires assays that allow the enzyme engineer to follow the kinase reaction, assays that are easily confused by ATPase and other spurious activities that might arise through "site-directed damage" of the natural kinases being engineered. This article introduces three assays that can detect the formation of both natural and unnatural deoxyribonucleoside triphosphates, assessing their value as polymerase substrates at the same time as monitoring the progress of kinase engineering. Here, we focus on two complementary AEGIS nucleoside diphosphates, 6-amino-5-nitro-3-(1'-β-D-2'-deoxyribofuranosyl)-2(1H)-pyridone and 2-amino-8-(1'-β-D-2'-deoxyribofuranosyl)-imidazo[1,2-a]-1,3,5-triazin-4(8H)-one. These assays provide new ways to detect the formation of unnatural deoxyribonucleoside triphosphates in vitro and to confirm their incorporation into DNA. Thus, these assays can be used with other unnatural nucleotides. PMID:26829203

  15. Effect of adenosine and adenosine receptor antagonist on Müller cell potassium channel in Rat chronic ocular hypertension models.

    Science.gov (United States)

    Yang, Zijian; Huang, Ping; Liu, Xiaohong; Huang, Shouyue; Deng, Lianfu; Jin, Zhe; Xu, Shuo; Shen, Xi; Luo, Xunda; Zhong, Yisheng

    2015-01-01

    Müller cells are principal glial cells in rat retina and have attracted much attention in glaucoma studies. However, it is not clear whether adenosine and adenosine receptor (AR) antagonists play any roles in the regulation of potassium channels in Müller cells and subsequently in the promotion of glutamine synthetase (GS) and L-Glutamate/L-Aspartate Transporter (GLAST) functions. We found that chronic ocular hypertension (COH) in rat down-regulated Müller cells Kir2.1, Kir4.1, TASK-1, GS and GLAST expressions and attenuated the peak of inward potassium current. Retinal ganglion cells (RGC) count was lower in the COH rats than that in the sham operation animals. Intravitreal injection of selective A2A AR antagonist SCH442416 up-regulated Müller cell Kir4.1, TASK-1, GS and GLAST expressions and enhanced inward potassium currents compared with those in the COH rats with vehicle control. Meanwhile, the RGC count was higher following intravitreal injection of SCH442416 in the COH rats than that after vehicle injection. The fact that PKA inhibitor H-89 blocked these SCH442416 effects suggested that the PKA signaling pathway was involved in the observed ocular responses following the intravitreal SCH442416 injection. PMID:26063641

  16. Adenosine, ketogenic diet and epilepsy: the emerging therapeutic relationship between metabolism and brain activity.

    Science.gov (United States)

    Masino, S A; Kawamura, M; Wasser, C D; Wasser, C A; Pomeroy, L T; Ruskin, D N

    2009-09-01

    For many years the neuromodulator adenosine has been recognized as an endogenous anticonvulsant molecule and termed a "retaliatory metabolite." As the core molecule of ATP, adenosine forms a unique link between cell energy and neuronal excitability. In parallel, a ketogenic (high-fat, low-carbohydrate) diet is a metabolic therapy that influences neuronal activity significantly, and ketogenic diets have been used successfully to treat medically-refractory epilepsy, particularly in children, for decades. To date the key neural mechanisms underlying the success of dietary therapy are unclear, hindering development of analogous pharmacological solutions. Similarly, adenosine receptor-based therapies for epilepsy and myriad other disorders remain elusive. In this review we explore the physiological regulation of adenosine as an anticonvulsant strategy and suggest a critical role for adenosine in the success of ketogenic diet therapy for epilepsy. While the current focus is on the regulation of adenosine, ketogenic metabolism and epilepsy, the therapeutic implications extend to acute and chronic neurological disorders as diverse as brain injury, inflammatory and neuropathic pain, autism and hyperdopaminergic disorders. Emerging evidence for broad clinical relevance of the metabolic regulation of adenosine will be discussed. PMID:20190967

  17. Role of adenosine signalling and metabolism in β-cell regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Olov, E-mail: olov.andersson@ki.se

    2014-02-01

    Glucose homeostasis, which is controlled by the endocrine cells of the pancreas, is disrupted in both type I and type II diabetes. Deficiency in the number of insulin-producing β cells – a primary cause of type I diabetes and a secondary contributor of type II diabetes – leads to hyperglycemia and hence an increase in the need for insulin. Although diabetes can be controlled with insulin injections, a curative approach is needed. A potential approach to curing diabetes involves regenerating the β-cell mass, e.g. by increasing β-cell proliferation, survival, neogenesis or transdifferentiation. The nucleoside adenosine and its cognate nucleotide ATP have long been known to affect insulin secretion, but have more recently been shown to increase β-cell proliferation during homeostatic control and regeneration of the β-cell mass. Adenosine is also known to have anti-inflammatory properties, and agonism of adenosine receptors can promote the survival of β-cells in an inflammatory microenvironment. In this review, both intracellular and extracellular mechanisms of adenosine and ATP are discussed in terms of their established and putative effects on β-cell regeneration. - Highlights: • A potential way to cure diabetes is to regenerate the β-cell mass by promoting cell survival, proliferation or neogenesis. • Adenosine may promote β-cell regeneration through several cellular mechanisms. • Adenosine and its cognate nucleotide ATP can each promote β-cell proliferation. • Do adenosine and ATP interact in promoting β-cell proliferation?.

  18. Susceptibility to seizure-induced sudden death in DBA/2 mice is altered by adenosine.

    Science.gov (United States)

    Faingold, Carl L; Randall, Marc; Kommajosyula, Srinivasa P

    2016-08-01

    Sudden unexpected death in epilepsy (SUDEP) is rare but is an important public health burden due to the number of patient years lost. Respiratory dysfunction following generalized convulsive seizure is a common sequence of events in witnessed SUDEP cases. The DBA/2 mouse model of SUDEP exhibits generalized convulsive audiogenic seizures (AGSz), which result in seizure-induced respiratory arrest (S-IRA) in ∼75% of these animals, while the remaining DBA/2 mice exhibit AGSz without S-IRA. SUDEP induction may involve actions of adenosine, which is released during generalized seizures in animals and patients and is known to depress respiration. This study examined the effects of systemic administration of agents that alter the actions of adenosine on the incidence of S-IRA in DBA/2 mice. DBA/2 mice that consistently exhibited AGSz without S-IRA showed a significantly increased incidence of S-IRA following treatment with 5-iodotubercidin, which blocks adenosine metabolism. Treatment of DBA/2 mice that consistently exhibited AGSz followed by S-IRA with a non-selective adenosine antagonist, caffeine, or an A2A adenosine receptor subtype-selective antagonist (SCH 442416) significantly reduced S-IRA incidence. By contrast, an A1 adenosine receptor antagonist (DPCPX) was not effective in reducing S-IRA incidence. These findings suggest that preventative approaches for SUDEP should consider agents that reduce the actions of adenosine. PMID:27259068

  19. Identification of an alternative nucleoside triphosphate: 5'-deoxyadenosylcobinamide phosphate nucleotidyltransferase in Methanobacterium thermoautotrophicum delta H.

    Science.gov (United States)

    Thomas, M G; Escalante-Semerena, J C

    2000-08-01

    Computer analysis of the archaeal genome databases failed to identify orthologues of all of the bacterial cobamide biosynthetic enzymes. Of particular interest was the lack of an orthologue of the bifunctional nucleoside triphosphate (NTP):5'-deoxyadenosylcobinamide kinase/GTP:adenosylcobinamide-phosphate guanylyltransferase enzyme (CobU in Salmonella enterica). This paper reports the identification of an archaeal gene encoding a new nucleotidyltransferase, which is proposed to be the nonorthologous replacement of the S. enterica cobU gene. The gene encoding this nucleotidyltransferase was identified using comparative genome analysis of the sequenced archaeal genomes. Orthologues of the gene encoding this activity are limited at present to members of the domain Archaea. The corresponding ORF open reading frame from Methanobacterium thermoautotrophicum Delta H (MTH1152; referred to as cobY) was amplified and cloned, and the CobY protein was expressed and purified from Escherichia coli as a hexahistidine-tagged fusion protein. This enzyme had GTP:adenosylcobinamide-phosphate guanylyltransferase activity but did not have the NTP:AdoCbi kinase activity associated with the CobU enzyme of S. enterica. NTP:adenosylcobinamide kinase activity was not detected in M. thermoautotrophicum Delta H cell extract, suggesting that this organism may not have this activity. The cobY gene complemented a cobU mutant of S. enterica grown under anaerobic conditions where growth of the cell depended on de novo adenosylcobalamin biosynthesis. cobY, however, failed to restore adenosylcobalamin biosynthesis in cobU mutants grown under aerobic conditions where de novo synthesis of this coenzyme was blocked, and growth of the cell depended on the assimilation of exogenous cobinamide. These data strongly support the proposal that the relevant cobinamide intermediates during de novo adenosylcobalamin biosynthesis are adenosylcobinamide-phosphate and adenosylcobinamide-GDP, not adenosylcobinamide

  20. Coxsackievirus cloverleaf RNA containing a 5' triphosphate triggers an antiviral response via RIG-I activation.

    Science.gov (United States)

    Feng, Qian; Langereis, Martijn A; Olagnier, David; Chiang, Cindy; van de Winkel, Roel; van Essen, Peter; Zoll, Jan; Hiscott, John; van Kuppeveld, Frank J M

    2014-01-01

    Upon viral infections, pattern recognition receptors (PRRs) recognize pathogen-associated molecular patterns (PAMPs) and stimulate an antiviral state associated with the production of type I interferons (IFNs) and inflammatory markers. Type I IFNs play crucial roles in innate antiviral responses by inducing expression of interferon-stimulated genes and by activating components of the adaptive immune system. Although pegylated IFNs have been used to treat hepatitis B and C virus infections for decades, they exert substantial side effects that limit their use. Current efforts are directed toward the use of PRR agonists as an alternative approach to elicit host antiviral responses in a manner similar to that achieved in a natural infection. RIG-I is a cytosolic PRR that recognizes 5' triphosphate (5'ppp)-containing RNA ligands. Due to its ubiquitous expression profile, induction of the RIG-I pathway provides a promising platform for the development of novel antiviral agents and vaccine adjuvants. In this study, we investigated whether structured RNA elements in the genome of coxsackievirus B3 (CVB3), a picornavirus that is recognized by MDA5 during infection, could activate RIG-I when supplied with 5'ppp. We show here that a 5'ppp-containing cloverleaf (CL) RNA structure is a potent RIG-I inducer that elicits an extensive antiviral response that includes induction of classical interferon-stimulated genes, as well as type III IFNs and proinflammatory cytokines and chemokines. In addition, we show that prophylactic treatment with CVB3 CL provides protection against various viral infections including dengue virus, vesicular stomatitis virus and enterovirus 71, demonstrating the antiviral efficacy of this RNA ligand. PMID:24759703

  1. CaMKII Regulation of Cardiac Ryanodine Receptors and Inositol Triphosphate Receptors

    Directory of Open Access Journals (Sweden)

    Emmanuel eCamors

    2014-05-01

    Full Text Available Ryanodine receptors (RyRs and inositol triphosphate receptors (InsP3Rs are structurally related intracellular calcium release channels that participate in multiple primary or secondary amplified Ca2+ signals, triggering muscle contraction and oscillatory Ca2+ waves, or activating transcription factors. In the heart, RyRs play an indisputable role in the process of excitation-contraction coupling as the main pathway for Ca2+ release from sarcoplasmic reticulum (SR, and a less prominent role in the process of excitation-transcription coupling. Conversely, InsP3Rs are believed to contribute in subtle ways, only, to contraction of the heart, and in more important ways to regulation of transcription factors. Because uncontrolled activity of either RyRs or InsP3Rs may elicit life-threatening arrhythmogenic and/or remodeling Ca2+ signals, regulation of their activity is of paramount importance for normal cardiac function. Due to their structural similarity, many regulatory factors, accessory proteins, and posttranslational processes are equivalent for RyRs and InsP3Rs. Here we discuss regulation of RyRs and InsP3Rs by CaMKII phosphorylation, but touch on other kinases whenever appropriate. CaMKII is emerging as a powerful modulator of RyR and InsP3R activity but interestingly, some of the complexities and controversies surrounding phosphorylation of RyRs also apply to InsP3Rs, and a clear-cut effect of CaMKII on either channel eludes investigators for now. Nevertheless, some effects of CaMKII on global cellular activity, such as SR Ca2+ leak or force-frequency potentiation, appear clear now, and this constrains the limits of the controversies and permits a more tractable approach to elucidate the effects of phosphorylation at the single channel level.

  2. Coxsackievirus cloverleaf RNA containing a 5' triphosphate triggers an antiviral response via RIG-I activation.

    Directory of Open Access Journals (Sweden)

    Qian Feng

    Full Text Available Upon viral infections, pattern recognition receptors (PRRs recognize pathogen-associated molecular patterns (PAMPs and stimulate an antiviral state associated with the production of type I interferons (IFNs and inflammatory markers. Type I IFNs play crucial roles in innate antiviral responses by inducing expression of interferon-stimulated genes and by activating components of the adaptive immune system. Although pegylated IFNs have been used to treat hepatitis B and C virus infections for decades, they exert substantial side effects that limit their use. Current efforts are directed toward the use of PRR agonists as an alternative approach to elicit host antiviral responses in a manner similar to that achieved in a natural infection. RIG-I is a cytosolic PRR that recognizes 5' triphosphate (5'ppp-containing RNA ligands. Due to its ubiquitous expression profile, induction of the RIG-I pathway provides a promising platform for the development of novel antiviral agents and vaccine adjuvants. In this study, we investigated whether structured RNA elements in the genome of coxsackievirus B3 (CVB3, a picornavirus that is recognized by MDA5 during infection, could activate RIG-I when supplied with 5'ppp. We show here that a 5'ppp-containing cloverleaf (CL RNA structure is a potent RIG-I inducer that elicits an extensive antiviral response that includes induction of classical interferon-stimulated genes, as well as type III IFNs and proinflammatory cytokines and chemokines. In addition, we show that prophylactic treatment with CVB3 CL provides protection against various viral infections including dengue virus, vesicular stomatitis virus and enterovirus 71, demonstrating the antiviral efficacy of this RNA ligand.

  3. Severe hemorrhage attenuates cardiopulmonary chemoreflex control of regional sympathetic outputs via NTS adenosine receptors.

    Science.gov (United States)

    Minic, Zeljka; Li, Cailian; O'Leary, Donal S; Scislo, Tadeusz J

    2014-09-15

    Selective stimulation of inhibitory A1 and facilitatory A2a adenosine receptor subtypes located in the nucleus of the solitary tract (NTS) powerfully inhibits cardiopulmonary chemoreflex (CCR) control of regional sympathetic outputs via different mechanisms: direct inhibition of glutamate release and facilitation of an inhibitory neurotransmitter release, respectively. However, it remains unknown whether adenosine naturally released into the NTS has similar inhibitory effects on the CCR as the exogenous agonists do. Our previous study showed that adenosine is released into the NTS during severe hemorrhage and contributes to reciprocal changes of renal (decreases) and adrenal (increases) sympathetic nerve activity observed in this setting. Both A1 and A2a adenosine receptors are involved. Therefore, we tested the hypothesis that, during severe hemorrhage, CCR control of the two sympathetic outputs is attenuated by adenosine naturally released into the NTS. We compared renal and adrenal sympathoinhibitory responses evoked by right atrial injections of 5HT3 receptor agonist phenylbiguanide (2-8 μg/kg) under control conditions, during hemorrhage, and during hemorrhage preceded by blockade of NTS adenosine receptors with bilateral microinjections of 8-(p-sulfophenyl) theophylline (1 nmol/100 nl) in urethane/chloralose anesthetized rats. CCR-mediated inhibition of renal and adrenal sympathetic activity was significantly attenuated during severe hemorrhage despite reciprocal changes in the baseline activity levels, and this attenuation was removed by bilateral blockade of adenosine receptors in the caudal NTS. This confirmed that adenosine endogenously released into the NTS has a similar modulatory effect on integration of cardiovascular reflexes as stimulation of NTS adenosine receptors with exogenous agonists. PMID:25063794

  4. Adenosine Modulates the Oocyte Developmental Competence by Exposing Stages and Synthetic Blocking during In Vitro Maturation.

    Science.gov (United States)

    Cheon, Yong-Pil

    2016-06-01

    Purine metabolism is known factor for nuclear maturation of oocytes through both follicle cells and oocyte itself. However, it is largely unknown the roles of purine metabolism in the oocyte competence for fertilization and early development. In this study, the effects of adenosine in oocyte competence for development were examined using adenosine and its synthetic inhibitors. Adenosine treatment from GV intact stage for 18 hr (fGV) caused of decrease the fertilization rate but of increase the cleavage rate compared from the other stage treatment groups. Hadacidin did not effect on fertilization rate but increased cleavage rate without stage specificity. Adenosine did not block the effects of hadacidin with the exception of fGV group. By the inhibition of purine synthetic pathways the fertilization rate was decreased in the fGV and fGVB groups but increased in the fMII group. Exogenous adenosine caused of decrease fertilization rate in the fGVB group but increase in the fMII group. Cleavage rate was dramatically increased in the adenosine treatment with synthetic inhibitors. It means that the metabolism of purine has stage specific effects on fertilization and cleavage. Exogenous adenosine had only can improve oocyte developmental competence when it treated at GV intact stage. On the other hand, endogenous synthesis in all maturation stage caused of increase the cleavage rate without effects on fertilization. These data suggest that adenosine at GV stage as a paracrine fashion and inhibitions of endogenous adenosine in all stage improve oocyte developmental competence.. PMID:27660830

  5. Severe hemorrhage attenuates cardiopulmonary chemoreflex control of regional sympathetic outputs via NTS adenosine receptors.

    Science.gov (United States)

    Minic, Zeljka; Li, Cailian; O'Leary, Donal S; Scislo, Tadeusz J

    2014-09-15

    Selective stimulation of inhibitory A1 and facilitatory A2a adenosine receptor subtypes located in the nucleus of the solitary tract (NTS) powerfully inhibits cardiopulmonary chemoreflex (CCR) control of regional sympathetic outputs via different mechanisms: direct inhibition of glutamate release and facilitation of an inhibitory neurotransmitter release, respectively. However, it remains unknown whether adenosine naturally released into the NTS has similar inhibitory effects on the CCR as the exogenous agonists do. Our previous study showed that adenosine is released into the NTS during severe hemorrhage and contributes to reciprocal changes of renal (decreases) and adrenal (increases) sympathetic nerve activity observed in this setting. Both A1 and A2a adenosine receptors are involved. Therefore, we tested the hypothesis that, during severe hemorrhage, CCR control of the two sympathetic outputs is attenuated by adenosine naturally released into the NTS. We compared renal and adrenal sympathoinhibitory responses evoked by right atrial injections of 5HT3 receptor agonist phenylbiguanide (2-8 μg/kg) under control conditions, during hemorrhage, and during hemorrhage preceded by blockade of NTS adenosine receptors with bilateral microinjections of 8-(p-sulfophenyl) theophylline (1 nmol/100 nl) in urethane/chloralose anesthetized rats. CCR-mediated inhibition of renal and adrenal sympathetic activity was significantly attenuated during severe hemorrhage despite reciprocal changes in the baseline activity levels, and this attenuation was removed by bilateral blockade of adenosine receptors in the caudal NTS. This confirmed that adenosine endogenously released into the NTS has a similar modulatory effect on integration of cardiovascular reflexes as stimulation of NTS adenosine receptors with exogenous agonists.

  6. Possible therapeutic benefits of adenosine-potentiating drugs in reducing age-related degenerative disease in dogs and cats.

    Science.gov (United States)

    Scaramuzzi, R J; Baker, D J

    2003-10-01

    Adenosine is a ubiquitous, biologically important molecule that is a precursor of other biologically active molecules. It also is a component of some co-factors and has distinct physiological actions in its own right. Levels are maintained by synthesis from dietary precursors and re-cycling. The daily turnover of adenosine is very high. Adenosine can act either as a hormone by binding to adenosine receptors, four adenosine receptor subtypes have been identified, and as an intracellular modulator, after transport into the cell by membrane transporter proteins. One of the principal intracellular actions of adenosine is inhibition of the enzyme phosphodiesterase. Extracellular adenosine also has specific neuromodulatory actions on dopamine and glutamate. Selective and nonselective agonists and antagonists of adenosine are available. The tasks of developing, evaluating and exploiting the therapeutic potential of these compounds is still in its infancy. Adenosine has actions in the central nervous system (CNS), heart and vascular system, skeletal muscle and the immune system and the presence of receptors suggests potential actions in the gonads and other organs. Adenosine agonists improve tissue perfusion through actions on vascular smooth muscle and erythrocyte fluidity and they can be used to improve the quality of life in aged dogs. This article reviews the therapeutic potential of adenosine-potentiating drugs in the treatment of age-related conditions in companion animals, some of which may be exacerbated by castration or spaying at an early age. PMID:14633184

  7. Receptor crosstalk: haloperidol treatment enhances A2A adenosine receptor functioning in a transfected cell model

    OpenAIRE

    Trincavelli, Maria Letizia; Cuboni, Serena; Catena Dell’Osso, Mario; Maggio, Roberto; Klotz, Karl-Norbert; Novi, Francesca; Panighini, Anna; Daniele, Simona; Martini, Claudia

    2010-01-01

    A2A adenosine receptors are considered an excellent target for drug development in several neurological and psychiatric disorders. It is noteworthy that the responses evoked by A2A adenosine receptors are regulated by D2 dopamine receptor ligands. These two receptors are co-expressed at the level of the basal ganglia and interact to form functional heterodimers. In this context, possible changes in A2A adenosine receptor functional responses caused by the chronic blockade/activation of D2 dop...

  8. Adenosine concentrations in the interstitium of resting and contracting human skeletal muscle

    DEFF Research Database (Denmark)

    Hellsten, Ylva; Maclean, D.; Rådegran, G.;

    1998-01-01

    BACKGROUND: Adenosine has been proposed to be a locally produced regulator of blood flow in skeletal muscle. However, the fundamental questions of to what extent adenosine is formed in skeletal muscle tissue of humans, whether it is present in the interstitium, and where it exerts its vasodilatory...... effect remain unanswered. METHODS AND RESULTS: The interstitial adenosine concentration was determined in the vastus lateralis muscle of healthy humans via dialysis probes inserted in the muscle. The probes were perfused with buffer, and the dialysate samples were collected at rest and during graded knee...... concentration and a higher FaBF (2.22+/-0.18 L/min; PATP, ADP, and AMP increased from...

  9. The role of adenosine A2A receptors on neuromuscular transmission upon ageing

    OpenAIRE

    Pousinha, Paula Isabel Antunes, 1978-

    2012-01-01

    Tese de doutoramento, Ciências Biomédicas (Neurociências), Universidade de Lisboa, Faculdade de Medicina, 2012 Adenosine is a neuromodulator with important actions in the nervous system. The activation of adenosine A2A receptors has been shown to modulate the action of other receptors. Considering that it was observed an interaction between adenosine A2A receptors and TrkB receptors in hippocampus, I hypothesized that the activation of A2A receptors could also facilitate BDNF actions on ne...

  10. The adenosine A2B receptor is involved in anion secretion in human pancreatic duct Capan-1 epithelial cells

    DEFF Research Database (Denmark)

    Hayashi, M.; Inagaki, A.; Novak, Ivana;

    2016-01-01

    Adenosine modulates a wide variety of biological processes via adenosine receptors. In the exocrine pancreas, adenosine regulates transepithelial anion secretion in duct cells and is considered to play a role in acini-to-duct signaling. To identify the functional adenosine receptors and Cl− chann...

  11. Adenosine A2A receptor binding profile of two antagonists, ST1535 and KW6002: consideration on the presence of atypical adenosine A2A binding sites

    Directory of Open Access Journals (Sweden)

    Teresa Riccioni

    2010-08-01

    Full Text Available Adenosine A2A receptors seem to exist in typical (more in striatum and atypical (more in hippocampus and cortex subtypes. In the present study, we investigated the affinity of two adenosine A2A receptor antagonists, ST1535 [2 butyl -9-methyl-8-(2H-1,2,3-triazol 2-yl-9H-purin-6-xylamine] and KW6002 [(E-1,3-diethyl-8-(3,4-dimethoxystyryl-7-methyl-3,7-dihydro-1H-purine-2,6,dione] to the “typical” and “atypical” A2A binding sites. Affinity was determined by radioligand competition experiments in membranes from rat striatum and hippocampus. Displacement of the adenosine analog [3H]CGS21680 [2-p-(2-carboxyethylphenethyl-amino-5’-N-ethylcarbox-amidoadenosine] was evaluated in the absence or in the presence of either CSC [8-(3-chlorostyryl-caffeine], an adenosine A2A antagonist that pharmacologically isolates atypical binding sites, or DPCPX (8-cyclopentyl-1,3-dipropylxanthine, an adenosine A1 receptor antagonist that pharmacologically isolates typical binding site. ZM241385 [84-(2-[7-amino-2-(2-furyl [1,2,4]-triazol[2,3-a][1,3,5]triazin-5-yl amino]ethyl phenol] and SCH58261 [(5-amino-7-(β-phenylethyl-2-(8-furylpyrazolo(4,3-e-1,2,4-triazolo(1,5-c pyrimidine], two other adenosine A2A receptor antagonists, which were reported to differently bind to atypical and typical A2A receptors, were used as reference compounds. ST1535, KW6002, ZM241385 and SCH58261 displaced [3H]CGS21680 with higher affinity in striatum than in hippocampus. In hippocampus, no typical adenosine A2A binding was detected, and ST1535 was the only compound that occupied atypical A2A adenosine receptors. Present data are explained in terms of heteromeric association among adenosine A2A, A2B and A1 receptors, rather than with the presence of atypical A2A receptor subtype.

  12. The role of carotid chemoreceptors in the sympathetic activation by adenosine in humans.

    NARCIS (Netherlands)

    Timmers, H.J.L.M.; Rongen, G.A.P.J.M.; Karemaker, J.M.; Wieling, W.; Marres, H.A.M.; Lenders, J.W.M.

    2004-01-01

    The direct vasodilatory and negative chronotropic effects of adenosine in humans are counterbalanced by a reflex increase in sympathetic nerve traffic. A suggested mechanism for this reflex includes peripheral chemoreceptor activation. We, therefore, assessed the contribution of carotid chemorecepto

  13. Influence of the adenosine A1 receptor on blood pressure regulation and renin release

    DEFF Research Database (Denmark)

    Brown, Russell D.; Thorén, Peter; Steege, Andreas;

    2006-01-01

    The present study was performed to investigate the role of adenosine A1 receptors in regulating blood pressure in conscious mice. Adenosine A1-receptor knockout (A1R-/-) mice and their wild-type (A1R+/+) littermates were placed on standardized normal-salt (NS), high-salt (HS), or salt-deficient (SD...... in sodium excretion between the two genotypes on the HS diet. Even on the SD diet, A1R-/- mice had an increased sodium excretion compared with A1R+/+ mice. An abolished tubuloglomerular feedback response and reduced tubular reabsorption can account for the elevated salt excretion found in A1R-/- animals....... The elevated plasma renin concentrations found in the A1R-/- mice could also result in increased blood pressure. Our results confirm that adenosine, acting through the adenosine A1 receptor, plays an important role in regulating blood pressure, renin release, and sodium excretion....

  14. The effect of circulating adenosine on cerebral haemodynamics and headache generation in healthy subjects

    DEFF Research Database (Denmark)

    Birk, S; Petersen, K.A.; Kruuse, Christina Rostrup;

    2005-01-01

    Adenosine is an endogenous neurotransmitter that is released from the brain during hypoxia and relaxes isolated human cerebral arteries. Many cerebral artery dilators cause migraine attacks. However, the effect of intravenous adenosine on headache and cerebral artery diameter has not previously...... been investigated in man and reports regarding the effect of intravenous adenosine on cerebral blood flow are conflicting. Twelve healthy participants received adenosine 80, 120 microg kg(-1) min(-1) and placebo intravenously for 20 min, in a double-blind, three-way, crossover, randomized design....... Headache was rated on a verbal scale (0-10). Regional cerebral blood flow (rCBF) with 133Xe inhalation and single-photon emission computed tomography (SPECT) and MCA flow velocity (V(MCA)) with transcranial Doppler, were measured in direct sequence. Six participants developed headache during 80 microg kg...

  15. Probing the ATP Site of GRP78 with Nucleotide Triphosphate Analogs.

    Directory of Open Access Journals (Sweden)

    Scott J Hughes

    Full Text Available GRP78, a member of the ER stress protein family, can relocate to the surface of cancer cells, playing key roles in promoting cell proliferation and metastasis. GRP78 consists of two major functional domains: the ATPase and protein/peptide-binding domains. The protein/peptide-binding domain of cell-surface GRP78 has served as a novel functional receptor for delivering cytotoxic agents (e.g., a apoptosis-inducing peptide or taxol across the cell membrane. Here, we report our study on the ATPase domain of GRP78 (GRP78ATPase, whose potential as a transmembrane delivery system of cytotoxic agents (e.g., ATP-based nucleotide triphosphate analogs remains unexploited. As the binding of ligands (ATP analogs to a receptor (GRP78ATPase is a pre-requisite for internalization, we determined the binding affinities and modes of GRP78ATPase for ADP, ATP and several ATP analogs using surface plasmon resonance and x-ray crystallography. The tested ATP analogs contain one of the following modifications: the nitrogen at the adenine ring 7-position to a carbon atom (7-deazaATP, the oxygen at the β-γ bridge position to a carbon atom (AMPPCP, or the removal of the 2'-OH group (2'-deoxyATP. We found that 7-deazaATP displays an affinity and a binding mode that resemble those of ATP regardless of magnesium ion (Mg++ concentration, suggesting that GRP78 is tolerant to modifications at the 7-position. By comparison, AMPPCP's binding affinity was lower than ATP and Mg++-dependent, as the removal of Mg++ nearly abolished binding to GRP78ATPase. The AMPPCP-Mg++ structure showed evidence for the critical role of Mg++ in AMPPCP binding affinity, suggesting that while GRP78 is sensitive to modifications at the β-γ bridge position, these can be tolerated in the presence of Mg++. Furthermore, 2'-deoxyATP's binding affinity was significantly lower than those for all other nucleotides tested, even in the presence of Mg++. The 2'-deoxyATP structure showed the conformation of the

  16. Probing the ATP Site of GRP78 with Nucleotide Triphosphate Analogs.

    Science.gov (United States)

    Hughes, Scott J; Antoshchenko, Tetyana; Chen, Yun; Lu, Hua; Pizarro, Juan C; Park, Hee-Won

    2016-01-01

    GRP78, a member of the ER stress protein family, can relocate to the surface of cancer cells, playing key roles in promoting cell proliferation and metastasis. GRP78 consists of two major functional domains: the ATPase and protein/peptide-binding domains. The protein/peptide-binding domain of cell-surface GRP78 has served as a novel functional receptor for delivering cytotoxic agents (e.g., a apoptosis-inducing peptide or taxol) across the cell membrane. Here, we report our study on the ATPase domain of GRP78 (GRP78ATPase), whose potential as a transmembrane delivery system of cytotoxic agents (e.g., ATP-based nucleotide triphosphate analogs) remains unexploited. As the binding of ligands (ATP analogs) to a receptor (GRP78ATPase) is a pre-requisite for internalization, we determined the binding affinities and modes of GRP78ATPase for ADP, ATP and several ATP analogs using surface plasmon resonance and x-ray crystallography. The tested ATP analogs contain one of the following modifications: the nitrogen at the adenine ring 7-position to a carbon atom (7-deazaATP), the oxygen at the β-γ bridge position to a carbon atom (AMPPCP), or the removal of the 2'-OH group (2'-deoxyATP). We found that 7-deazaATP displays an affinity and a binding mode that resemble those of ATP regardless of magnesium ion (Mg++) concentration, suggesting that GRP78 is tolerant to modifications at the 7-position. By comparison, AMPPCP's binding affinity was lower than ATP and Mg++-dependent, as the removal of Mg++ nearly abolished binding to GRP78ATPase. The AMPPCP-Mg++ structure showed evidence for the critical role of Mg++ in AMPPCP binding affinity, suggesting that while GRP78 is sensitive to modifications at the β-γ bridge position, these can be tolerated in the presence of Mg++. Furthermore, 2'-deoxyATP's binding affinity was significantly lower than those for all other nucleotides tested, even in the presence of Mg++. The 2'-deoxyATP structure showed the conformation of the bound

  17. Reduced striatal ecto-nucleotidase activity in schizophrenia patients supports the “adenosine hypothesis”

    OpenAIRE

    Aliagas, Elisabet; Villar-Menéndez, Izaskun; Sévigny, Jean; Roca, Mercedes; Romeu, Miriam; Ferrer, Isidre; Martín-Satué, Mireia; Barrachina, Marta

    2013-01-01

    Schizophrenia (SZ) is a major chronic neuropsychiatric disorder characterized by a hyperdopaminergic state. The hypoadenosinergic hypothesis proposes that reduced extracellular adenosine levels contribute to dopamine D2 receptor hyperactivity. ATP, through the action of ecto-nucleotidases, constitutes a main source of extracellular adenosine. In the present study, we examined the activity of ecto-nucleotidases (NTPDases, ecto-5′-nucleotidase, and alkaline phosphatase) in the postmortem putame...

  18. Severe hemorrhage attenuates cardiopulmonary chemoreflex control of regional sympathetic outputs via NTS adenosine receptors

    OpenAIRE

    Minic, Zeljka; Li, Cailian; O'Leary, Donal S.; Scislo, Tadeusz J.

    2014-01-01

    Selective stimulation of inhibitory A1 and facilitatory A2a adenosine receptor subtypes located in the nucleus of the solitary tract (NTS) powerfully inhibits cardiopulmonary chemoreflex (CCR) control of regional sympathetic outputs via different mechanisms: direct inhibition of glutamate release and facilitation of an inhibitory neurotransmitter release, respectively. However, it remains unknown whether adenosine naturally released into the NTS has similar inhibitory effects on the CCR as th...

  19. Effect of insulin and glucose on adenosine metabolizing enzymes in human B lymphocytes.

    Science.gov (United States)

    Kocbuch, Katarzyna; Sakowicz-Burkiewicz, Monika; Grden, Marzena; Szutowicz, Andrzej; Pawelczyk, Tadeusz

    2009-01-01

    In diabetes several aspects of immunity are altered, including the immunomodulatory action of adenosine. Our study was undertaken to investigate the effect of different glucose and insulin concentrations on activities of adenosine metabolizing enzymes in human B lymphocytes line SKW 6.4. The activity of adenosine deaminase in the cytosolic fraction was very low and was not affected by different glucose concentration, but in the membrane fraction of cells cultured with 25 mM glucose it was decreased by about 35% comparing to the activity in cells maintained in 5 mM glucose, irrespective of insulin concentration. The activities of 5'-nucleotidase (5'-NT) and ecto-5'-NT in SKW 6.4 cells depended on insulin concentration, but not on glucose. Cells cultured with 10(-8) M insulin displayed an about 60% lower activity of cytosolic 5'-NT comparing to cells maintained at 10(-11) M insulin. The activity of ecto-5'-NT was decreased by about 70% in cells cultured with 10(-8) M insulin comparing to cells grown in 10(-11) M insulin. Neither insulin nor glucose had an effect on adenosine kinase (AK) activity in SKW 6.4 cells or in human B cells isolated from peripheral blood. The extracellular level of adenosine and inosine during accelerated catabolism of cellular ATP depended on glucose, but not on insulin concentration. Concluding, our study demonstrates that glucose and insulin differentially affect the activities of adenosine metabolizing enzymes in human B lymphocytes, but changes in those activities do not correlate with the adenosine level in cell media during accelerated ATP catabolism, implying that nucleoside transport is the primary factor determining the extracellular level of adenosine.

  20. Methotrexate inhibits neutrophil function by stimulating adenosine release from connective tissue cells.

    OpenAIRE

    Cronstein, B. N.; Eberle, M A; Gruber, H E; Levin, R I

    1991-01-01

    Although commonly used to control a variety of inflammatory diseases, the mechanism of action of a low dose of methotrexate remains a mystery. Methotrexate accumulates intracellularly where it may interfere with purine metabolism. Therefore, we determined whether a 48-hr pretreatment with methotrexate affected adenosine release from [14C]adenine-labeled human fibroblasts and umbilical vein endothelial cells. Methotrexate significantly increased adenosine release by fibroblasts from 4 +/- 1% t...

  1. Regulation of aggregate size and pattern by adenosine and caffeine in cellular slime molds

    OpenAIRE

    Jaiswal Pundrik; Soldati Thierry; Thewes Sascha; Baskar Ramamurthy

    2012-01-01

    Abstract Background Multicellularity in cellular slime molds is achieved by aggregation of several hundreds to thousands of cells. In the model slime mold Dictyostelium discoideum, adenosine is known to increase the aggregate size and its antagonist caffeine reduces the aggregate size. However, it is not clear if the actions of adenosine and caffeine are evolutionarily conserved among other slime molds known to use structurally unrelated chemoattractants. We have examined how the known factor...

  2. Enzymatic Recognition of 2′‐Modified Ribonucleoside 5′‐Triphosphates: Towards the Evolution of Versatile Aptamers

    DEFF Research Database (Denmark)

    Lauridsen, Lasse Holm; Rothnagel, Joseph A.; Veedu, Rakesh N.

    2012-01-01

    The quest for effective, selective and nontoxic nucleic‐acid‐based drugs has led to designing modifications of naturally occurring nucleosides. A number of modified nucleic acids have been made in the past decades in the hope that they would prove useful in target‐validation studies and therapeutic...... of aptamers containing naturally occurring nucleotides, chemically modified nucleotides have to be used. In order to apply modified nucleotides in aptamer drug development, their enzyme‐recognition capabilities must be understood. For this purpose, several modified nucleoside 5′‐triphosphates were synthesized...

  3. Cross-linked polymeric nanogel formulations of 5'-triphosphates of nucleoside analogues: role of the cellular membrane in drug release.

    Science.gov (United States)

    Vinogradov, Serguei V; Kohli, Ekta; Zeman, Arin D

    2005-01-01

    Activation of cytotoxic nucleoside analogues in vivo depends primarily on their cell-specific phosphorylation. Anticancer chemotherapy using nucleoside analogues may be significantly enhanced by intracellular administration of active phosphorylated drugs. However, the cellular transport of anionic compounds is very ineffective and restricted by many drug efflux transporters. Recently developed cationic nanogel carriers can encapsulate large amounts of nucleoside 5'-triphosphates that form polyionic complexes with protonated amino groups on the polyethylenimine backbone of the nanogels. In this paper, the 5'-triphosphate of an antiviral nucleoside analogue, 3'-azido-2',3'-dideoxythymidine (AZT), was efficiently synthesized and its complexes with nanogels were obtained and evaluated as potential cytotoxic drug formulations for treatment of human breast carcinoma cells. A selective phosphorylating reagent, tris-imidazolylphosphate, was used to convert AZT into the nucleoside analogue 5'-triphosphate using a one-pot procedure. The corresponding 3'-azido-2',3'-dideoxythymidine 5'-triphosphate (AZTTP) was isolated with high yield (75%). Nanogels encapsulated up to 30% of AZTTP by weight by mixing solutions of the carrier and the drug. The AZTTP/nanogel formulation showed enhanced cytotoxicity in two breast cancer cell lines, MCF-7 and MDA-MB-231, demonstrating IC50 values 130-200 times lower than those values for AZT alone. The exact mechanism of drug release from nanogels remains unclear. One mechanism could involve interaction with negatively charged counterions. A high affinity of nanogels to isolated cellular membranes has been observed, especially for nanogels made of amphiphilic block copolymer, Pluronic P85. Cellular trafficking of nanogel particles, contrasted by polyethylenimine-coordinated copper(II) ions, was studied by transmission electron microscopy (TEM), which revealed membranotropic properties of nanogels. A substantial release of encapsulated drug was

  4. Aptamer-based Electrochemical Biosensors for Highly Selective and Quantitative Detection of Adenosine

    Institute of Scientific and Technical Information of China (English)

    ZHENG Fan; WU Zai-sheng; ZHANG Song-bai; GUO Meng-meng; CHEN Chen-rui; SHEN Guo-li; YU Ru-qin

    2008-01-01

    A new adenosine biosensor based on aptamer probe is introduced in this article.An amino-labeled aptamer probe was immobilized on the gold electrode modified with an o-phenylenediamine electropolymerized film.When adenosine is bound specifically to the aptamer probe,the interface of the biosensor is changed,resulting in the decrement of the peak current.The response current is proportional to the amount of adenosine in sample.The used electrode can be easily regenerated in hot water.The proposed biosensor represents a linear response to adenosine over a concentration range of 1.0×10-7-1.0×10-4 mol/L with a detection limit of 1.0×10-8 mol/L.The presented biosensor exhibits a nice specificity towards adenosine.It offers a promising approach for adenosine assay due to its excellent electrochemical properties that are believed to be very attractive for electrochemical studies and electroanalytical applications.

  5. Label-Free Sensing of Adenosine Based on Force Variations Induced by Molecular Recognition

    Directory of Open Access Journals (Sweden)

    Jingfeng Li

    2015-03-01

    Full Text Available We demonstrate a simple force-based label-free strategy for the highly sensitive sensing of adenosine. An adenosine ssDNA aptamer was bound onto an atomic force microscopy (AFM probe by covalent modification, and the molecular-interface adsorption force between the aptamer and a flat graphite surface was measured by single-molecule force spectroscopy (SMFS. In the presence of adenosine, the molecular recognition between adenosine and the aptamer resulted in the formation of a folded, hairpin-like DNA structure and hence caused a variation of the adsorption force at the graphite/water interface. The sensitive force response to molecular recognition provided an adenosine detection limit in the range of 0.1 to 1 nM. The addition of guanosine, cytidine, and uridine had no significant interference with the sensing of adenosine, indicating a strong selectivity of this sensor architecture. In addition, operational parameters that may affect the sensor, such as loading rate and solution ionic strength, were investigated.

  6. Methotrexate inhibits neutrophil function by stimulating adenosine release from connective tissue cells

    International Nuclear Information System (INIS)

    Although commonly used to control a variety of inflammatory diseases, the mechanism of action of a low dose of methotrexate remains a mystery. Methotrexate accumulates intracellularly where it may interfere with purine metabolism. Therefore, the authors determined whether a 48-hr pretreatment with methotrexate affected adenosine release from [14C]adenine-labeled human fibroblasts and umbilical vein endothelial cells. Methotrexate significantly increased adenosine release by fibroblasts. The effect of methotrexate on adenosine release was not due to cytotoxicity since cells treated with maximal concentrations of methotrexate took up [14C]adenine and released 14C-labeled purine (a measure of cell injury) in a manner identical to control cells. Methotrexate treatment of fibroblasts dramatically inhibited adherence to fibroblasts by both unstimulated neutrophils and stimulated neutrophils. One hypothesis that explains the effect of methotrexate on adenosine release is that, by inhibition of 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) transformylase, methotrexate induces the accumulation of AICAR, the nucleoside precursor of which has previously been shown to cause adenosine release from ischemic cardiac tissue. The observation that the antiinflammatory actions of methotrexate are due to the capacity of methotrexate to induce adenosine release may form the basis for the development of an additional class of antiinflammatory drugs

  7. Serum adenosine deaminase as oxidative stress marker in type 2 diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Shashikala Magadi Dasegowda

    2015-05-01

    Results: The study observed an increased level of serum adenosine deaminase, malondialdehyde and decreased levels of total antioxidant capacity in type 2 diabetes mellitus compared to controls. Serum adenosine deaminase levels in type 2 diabetics were 50.77 +/- 6.95 and in controls was 17.86 +/- 4.04. Serum Malondialdehyde levels in type 2 diabetics was 512.13 +/- 70.15 and in controls was 239.32 +/- 23.97. Serum total antioxidant levels in type 2 diabetics was 0.39+/-0.15 and in controls was 1.66+/-0.25. Positive correlation was seen between serum adenosine deaminase and malondialdehyde and it was statistically significant. Statistically significant negative correlation was seen between serum adenosine deaminase and total antioxidant capacity. Conclusion: Adenosine deaminase can be used as oxidative stress marker. Their increased levels indicate oxidative stress in type 2 diabetes mellitus. Therefore, estimation of serum adenosine deaminase levels help in early prediction and prevention of long term complications occurring due to oxidative stress in diabetics, thereby decreasing the mortality and morbidity in them. [Int J Res Med Sci 2015; 3(5.000: 1195-1198

  8. Suppression of adenosine-activated chloride transport by ethanol in airway epithelia.

    Directory of Open Access Journals (Sweden)

    Sammeta V Raju

    Full Text Available Alcohol abuse is associated with increased lung infections. Molecular understanding of the underlying mechanisms is not complete. Airway epithelial ion transport regulates the homeostasis of airway surface liquid, essential for airway mucosal immunity and lung host defense. Here, air-liquid interface cultures of Calu-3 epithelial cells were basolaterally exposed to physiologically relevant concentrations of ethanol (0, 25, 50 and 100 mM for 24 hours and adenosine-stimulated ion transport was measured by Ussing chamber. The ethanol exposure reduced the epithelial short-circuit currents (I(SC in a dose-dependent manner. The ion currents activated by adenosine were chloride conductance mediated by cystic fibrosis transmembrane conductance regulator (CFTR, a cAMP-activated chloride channel. Alloxazine, a specific inhibitor for A(2B adenosine receptor (A(2BAR, largely abolished the adenosine-stimulated chloride transport, suggesting that A(2BAR is a major receptor responsible for regulating the chloride transport of the cells. Ethanol significantly reduced intracellular cAMP production upon adenosine stimulation. Moreover, ethanol-suppression of the chloride secretion was able to be restored by cAMP analogs or by inhibitors to block cAMP degradation. These results imply that ethanol exposure dysregulates CFTR-mediated chloride transport in airways by suppression of adenosine-A(2BAR-cAMP signaling pathway, which might contribute to alcohol-associated lung infections.

  9. Functional proteomics of adenosine triphosphatase system in the rat striatum during aging

    Institute of Scientific and Technical Information of China (English)

    Roberto Federico Villa; Federica Ferrari; Antonella Gorini

    2012-01-01

    The maximum rates of adenosine triphosphatase (ATPase) systems related to energy consumption were systematically evaluated in synaptic plasma membranes isolated from the striata of male Wistar rats aged 2, 6, 12, 18, and 24 months, because of their key role in presynaptic nerve ending homeostasis. The following enzyme activities were evaluated: sodium-potassium-magnesium adenosine triphosphatase (Na+, K+, Mg2+-ATPase); ouabain-insensitive magnesium adenosine triphosphatase (Mg2+-ATPase); sodium-potassium adenosine triphosphatase (Na+, K+-ATPase); direct magnesium adenosine triphosphatase (Mg2+-ATPase); calcium-magnesium adenosine triphosphatase (Ca2+, Mg2+-ATPase); and acetylcholinesterase. The results showed that Na+, K+-ATPase decreased at 18 and 24 months, Ca2+, Mg2+-ATPase and acetylcholinesterase decreased from 6 months, while Mg2+-ATPase was unmodified. Therefore, ATPases vary independently during aging, suggesting that the ATPase enzyme systems are of neuropathological and pharmacological importance. This could be considered as an experimental model to study regeneration processes, because of the age-dependent modifications of specific synaptic plasma membranes. ATPases cause selective changes in some cerebral functions, especially bioenergetic systems. This could be of physiopathological significance, particularly in many central nervous system diseases, where, during regenerative processes, energy availability is essential.

  10. The Dynamics of the Microbial Population as Measured by the Quantification of adenosine 5'-triphosphate (ATP) at Three Sampling Locations Within the North Inlet Estuary, Georgetown, SC: 1981-1985.

    Data.gov (United States)

    Baruch Institute for Marine and Coastal Sciences, Univ of South Carolina — Water samples were collected daily at approximately 10:00 AM, from a depth of 50 cm at three stations, and transported immediately to the laboratory. The three...

  11. Profil Kinetik dan Efektivitas Enrofloksasin yang Dikombinasikan dengan BioATP dalam Mengatasi Coxiella burnetii (KINETIC PROFILE AND EFFECTIVITY OF ENROFLOXACINE WITH BIO ADENOSIN TRIPHOSPHATE SUPPLEMENTATION AGAINST COXIELLA BURNETII

    Directory of Open Access Journals (Sweden)

    Andriyanto .

    2013-11-01

    Full Text Available Coxiella burnetii belongs to rikettsia group living obligate intracellularly and as the agent of zoonosisQ fever. Enrofloxacine is an antibiotic in quinolon group used to treat infection of C. burnetii in chicken,goat, calve, pig, dog, cat,  and horse. From ruminant practical experience, enrofloxacine if combined withBioATP  can enhance the enrofloxacine activity. Research for the effecivity of enrofloxacine and BioATP totreat C. burnetii has never been carried out. The research was conducted to explore effect of enrofloxacinewith supplementation BioATP against C. burnetii. Enrofloxacine pharmacokinetic study was carried outby using simental beef as an experimental animals. The effectivity of BioATP supplementation onenrofloxacine activity to treat C. burnetii was tested by using Vero cell tissue culture. The results showedthat combination of enrofloxacine and BioATP increased kinetic profile of enrofloxacine in term of onset,duration, pharmacology intensity, and bioavailaibility. Enrofloxacine had activity to treat C. burnetii withvalue of minimal inhibitory concentration (MIC at 1-2 ppm and value of minimal bactericidal concentrationat 4 ppm. Supplementation of BioATP improved the effectivity of enrofloxacine in treating C. burnetii.

  12. 三磷酸腺苷致室性心律失常的机制研究%A study on the mechanism of ventricular arrhythmias induced by adenosine triphosphate

    Institute of Scientific and Technical Information of China (English)

    余更生; 钱永如; 田杰; 张德蓉; 钟家蓉; 刘晓燕

    2002-01-01

    目的:研究三磷酸腺苷(ATP)对正常和存在触发活动的兔在体心脏电生理作用,以探讨ATP致室性心律失常的机制.方法:应用接触电极记录心内膜单相动作电位(MAP)技术,观察ATP静脉快速注射对正常心脏MAP变化和氯化铯(CsCl)诱发触发活动时使用ATP对心脏的影响.结果:ATP对正常心脏的MAP振幅(MAPA)和0相最大上升速率(Vmax)影响不大,在初期心率减慢不明显,MAP时程(MAPD90)明显延长,并能诱发早期后除极(EAD),后期心率明显抑制,EAD消失,而对存在氯化铯(CsCi)诱发出EAD的心脏,具有双重作用,在作用初期对后除极(EAD或DAD)具有短暂促进作用,尔后迅速抑制.结论:ATP对不同心脏状态,有不同作用机制,表现为兴奋和抑制双重作用,并具有剂量相关性,值得临床使用上重视.

  13. Effect of adenosine triphosphate on detrusor muscle from unstable bladder of rat%ATP对大鼠逼尿肌不稳定膀胱的作用研究

    Institute of Scientific and Technical Information of China (English)

    郭建军; 方强; 宋波; 李龙坤; 李为兵

    2007-01-01

    目的 初步探讨ATP对大鼠逼尿肌不稳定膀胱的作用.方法 建立雌性SD大鼠BOO DI 模型,以正常雌性逼尿肌稳定(detrusor stability, DS)大鼠作对照,制作离体膀胱并Krebs液孵育,膀胱内分别给予0.9%NaCl、ATP、PPADS液后用0.9% NaCl液以0.1 ml/min的速度灌注膀胱,同法灌注膀胱时向浴液中加入ATP以及先浴液中加入PPADS孵育膀胱10 min后再灌注膀胱,并向浴液中加入ATP,记录灌注膀胱和停止灌注后各4 min内的膀胱压力曲线,测量20 s、50 s、4 min、8 min时的膀胱压力值.结果 离体膀胱内给予NaCl、ATP、PPADS后,2组大鼠膀胱压力曲线形态和组内和组间各时间点膀胱压无显著性差别(P>0.05).灌注时浴液中加入ATP,离体膀胱出现膀胱收缩,50 s时DS组膀胱压高于BOO DI组;先PPADS孵育膀胱后再加入ATP,膀胱收缩幅度显著降低,50 s时组间膀胱压无差别.结论 膀胱内给予或膀胱上皮细胞释放的ATP通过神经反射引起尿频和参与逼尿肌不稳定收缩,支配逼尿肌的嘌呤能神经释放的ATP可直接作用于逼尿肌引起收缩.

  14. 腺苷三磷酸对大鼠离体胃平滑肌运动的影响%Effects of adenosine triphosphate on motility of isolated gastric smooth muscle in rats

    Institute of Scientific and Technical Information of China (English)

    王秒; 赵丁; 赵庆华; 任雷鸣

    2005-01-01

    目的观察腺苷三磷酸(ATP)对大鼠离体胃平滑肌运动的调节作用.方法制备大鼠离体胃体纵行肌、胃体环行肌、胃窦纵行肌、胃窦环行肌标本,观察ATP(0.1,1,10,100 μmol·L-1和1 mmol·L-1)的作用.结果在胃体纵行肌标本,ATP诱发微弱的舒张反应,继而出现收缩反应;在高钾预收缩条件下,ATP则引起较大舒张反应后续较小的收缩反应.ATP对胃体环行肌诱发单相收缩反应.1~100 μmol·L-1 ATP抑制胃窦纵行肌的自发性收缩幅度,同时加快收缩频率;1 mmol·L-1 ATP则完全抑制自发性收缩反应;在高钾预收缩条件下,ATP产生浓度依赖性舒张反应.1~10 μmol·L-1 ATP先增大后减低胃窦环行肌的自发性收缩幅度,同时加快收缩频率; 100 μmol·L-1~1 mmol·L-1 ATP则抑制自发性收缩反应.结论本文首次报道了ATP影响大鼠离体胃体纵行肌、胃体环行肌、胃窦纵行肌、胃窦环行肌四种平滑肌的运动,且对各种标本的作用特点互不相同,提示ATP在生理条件下对大鼠胃的运动功能发挥重要的调节作用.

  15. Evaluation of Adenosine Triphosphate-Binding Cassette Transporter A1 (ABCA1) R219K and C-Reactive Protein Gene (CRP) +1059G/C Gene Polymorphisms in Susceptibility to Coronary Heart Disease.

    Science.gov (United States)

    Li, Jing-Fang; Peng, Dian-Ying; Ling, Mei; Yin, Yong

    2016-01-01

    BACKGROUND This meta-analysis investigated the correlation of ABCA1 R219K and C-Reactive Protein Gene (CRP) +1059G/C gene polymorphisms with susceptibility to coronary heart disease (CHD). MATERIAL AND METHODS We searched PubMed, Springer link, Wiley, EBSCO, Ovid, Wanfang database, VIP database, and China National Knowledge Infrastructure (CNKI) databases to retrieve published studies by keyword. Searches were filtered using our stringent inclusion and exclusion criteria. Resultant high-quality data collected from the final selected studies were analyzed using Comprehensive Meta-analysis 2.0 software. Eleven case-control studies involving 3053 CHD patients and 3403 healthy controls met our inclusion criteria. Seven studies were conducted in Asian populations, 3 studies were done in Caucasian populations, and 1 was in an African population. RESULTS Our major finding was that ABCA1 R219K polymorphism increased susceptibility to CHD in allele model (OR=0.729, 95% CI=0.559~0.949, P=0.019) and dominant model (OR=0.698, 95% CI=0.507~0.961, P=0.027). By contrast, we were unable to find any significant association between the CRP +1059G/C polymorphism and susceptibility to CHD (allele model: OR=1.170, 95% CI=0.782~1.751, P=0.444; dominant model: OR=1.175, 95% CI=0.768~1.797, P=0.457). CONCLUSIONS This meta-analysis provides convincing evidence that polymorphism of ABCA1 R219K is associated with susceptibility to CHD while the CRP +1059G/C polymorphism appears to have no correlation with susceptibility to CHD. PMID:27560308

  16. Evaluation of Adenosine Triphosphate-Binding Cassette Transporter A1 (ABCA1) R219K and C-Reactive Protein Gene (CRP) +1059G/C Gene Polymorphisms in Susceptibility to Coronary Heart Disease.

    Science.gov (United States)

    Li, Jing-Fang; Peng, Dian-Ying; Ling, Mei; Yin, Yong

    2016-08-25

    BACKGROUND This meta-analysis investigated the correlation of ABCA1 R219K and C-Reactive Protein Gene (CRP) +1059G/C gene polymorphisms with susceptibility to coronary heart disease (CHD). MATERIAL AND METHODS We searched PubMed, Springer link, Wiley, EBSCO, Ovid, Wanfang database, VIP database, and China National Knowledge Infrastructure (CNKI) databases to retrieve published studies by keyword. Searches were filtered using our stringent inclusion and exclusion criteria. Resultant high-quality data collected from the final selected studies were analyzed using Comprehensive Meta-analysis 2.0 software. Eleven case-control studies involving 3053 CHD patients and 3403 healthy controls met our inclusion criteria. Seven studies were conducted in Asian populations, 3 studies were done in Caucasian populations, and 1 was in an African population. RESULTS Our major finding was that ABCA1 R219K polymorphism increased susceptibility to CHD in allele model (OR=0.729, 95% CI=0.559~0.949, P=0.019) and dominant model (OR=0.698, 95% CI=0.507~0.961, P=0.027). By contrast, we were unable to find any significant association between the CRP +1059G/C polymorphism and susceptibility to CHD (allele model: OR=1.170, 95% CI=0.782~1.751, P=0.444; dominant model: OR=1.175, 95% CI=0.768~1.797, P=0.457). CONCLUSIONS This meta-analysis provides convincing evidence that polymorphism of ABCA1 R219K is associated with susceptibility to CHD while the CRP +1059G/C polymorphism appears to have no correlation with susceptibility to CHD.

  17. Evaluation of Adenosine Triphosphate-Binding Cassette Transporter A1 (ABCA1) R219K and C-Reactive Protein Gene (CRP) +1059G/C Gene Polymorphisms in Susceptibility to Coronary Heart Disease

    Science.gov (United States)

    Li, Jing-Fang; Peng, Dian-Ying; Ling, Mei; Yin, Yong

    2016-01-01

    Background This meta-analysis investigated the correlation of ABCA1 R219K and CRP +1059G/C gene polymorphisms with susceptibility to coronary heart disease (CHD). Material/Methods We searched PubMed, Springer link, Wiley, EBSCO, Ovid, Wanfang database, VIP database, and China National Knowledge Infrastructure (CNKI) databases to retrieve published studies by keyword. Searches were filtered using our stringent inclusion and exclusion criteria. Resultant high-quality data collected from the final selected studies were analyzed using Comprehensive Meta-analysis 2.0 software. Eleven case-control studies involving 3053 CHD patients and 3403 healthy controls met our inclusion criteria. Seven studies were conducted in Asian populations, 3 studies were done in Caucasian populations, and 1 was in an African population. Results Our major finding was that ABCA1 R219K polymorphism increased susceptibility to CHD in allele model (OR=0.729, 95% CI=0.559~0.949, P=0.019) and dominant model (OR=0.698, 95% CI=0.507~0.961, P=0.027). By contrast, we were unable to find any significant association between the CRP +1059G/C polymorphism and susceptibility to CHD (allele model: OR=1.170, 95% CI=0.782~1.751, P=0.444; dominant model: OR=1.175, 95% CI=0.768~1.797, P=0.457). Conclusions This meta-analysis provides convincing evidence that polymorphism of ABCA1 R219K is associated with susceptibility to CHD while the CRP +1059G/C polymorphism appears to have no correlation with susceptibility to CHD. PMID:27560308

  18. Studies on adenosine triphosphate transphosphorylases. XVIII. Synthesis and preparation of peptides and peptide fragments of rabbit muscle ATP-AMP transphosphorylase (adenylate kinase) and their nucleotide-binding properties.

    Science.gov (United States)

    Kuby, S A; Hamada, M; Johnson, M S; Russell, G A; Manship, M; Palmieri, R H; Fleming, G; Bredt, D S; Mildvan, A S

    1989-08-01

    Two peptide fragments, derived from the head and tail of rabbit muscle myokinase, were found to possess remarkable and specific ligand-binding properties (Hamada et al., 1979). By initiating systematic syntheses and measurements of equilibrium substrate-binding properties of these two sets of peptides, or portions thereof, which encompass the binding sites for (a) the magnesium complexes of the nucleotide substrates (MgATP2- and MgADP-) and (b) the uncomplexed nucleotide substrates (ADP3- and AMP2-) of rabbit muscle myokinase, some of the requirements for binding of the substrates to ATP-AMP transphosphorylase are being deduced and chemically outlined. One requirement for tight nucleotide binding appears to be a minimum peptide length of 15-25 residues. In addition, Lys-172 and/or Lys-194 may be involved in the binding of epsilon AMP. The syntheses are described as a set of peptides corresponding to residues 31-45, 20-45, 5-45, and 1-45, and a set of peptides corresponding to residues 178-192, 178-194, and 172-194 of rabbit muscle adenylate kinase. The ligand-binding properties of the first set of synthetic peptides to the fluorescent ligands: epsilon MgATP/epsilon ATP and epsilon MgADP/epsilon ADP are quantitatively presented in terms of their intrinsic dissociation constants (K'd) and values of N (maximal number of moles bound per mole of peptide); and compared with the peptide fragment MT-I (1-44) obtained from rabbit muscle myokinase (Kuby et al., 1984) and with the native enzyme (Hamada et al., 1979). In addition, the values of N and K'd are given for the second set of synthetic peptides to the fluorescent ligands epsilon AMP and epsilon ADP as well as for the peptide fragments MT-XII(172-194) and CB-VI(126-194) (Kuby et al., 1984) and, in turn, compared with the native enzyme. A few miscellaneous dissociation constants which had been derived kinetically are also given for comparison (e.g., the Ki for epsilon AMP and the value of KMg epsilon ATP obtained for the native enzyme) (Hamada and Kuby, 1978), and the K'd measured for Cr3+ ATP [corrected] and the synthetic peptide I1-45 (Fry et al., 1985b).

  19. Adenosine Deaminase Activity in Chronic Lymphocytic Leukemia and Healthy Subjects

    Science.gov (United States)

    Ghaderi, Bayazid; Amini, Sabrieh; Maroofi, Farzad; Jalali, Chiya; Javanmardi, Mitra; Roshani, Daem; Abdi, Mohammad

    2016-01-01

    Background B cell chronic lymphocytic leukemia is one of the most frequent hematologic malignancies in the world. Cellular surface CD markers and serum Beta-2-microglobulin may be used as a prognostic tool in CLL patients. Objectives In the present study we introduce serum adenosine deaminase as a diagnostic marker in CLL. Materials and Methods Blood samples were collected from B-CLL and healthy subjects. White blood cell, red blood cell and platelet count and blood Erythrocyte sedimentation rate was recorded and serum Beta-2-microglobulin, Lactate dehydrogenase and total ADA enzyme activity were determined. Results Serum ADA activity was significantly higher in patients group than that of controls. ADA had a significant and direct correlation with B2M, WBC, LDH and ESR. However, there was not any relation between ADA and the stages of disease. Diagnostic cut-off, sensitivity and specificity of the serum ADA test were 27.97 U/L, 91% and 94%, respectively. Conclusions A higher ADA activity in patients group and its correlation with CLL markers were seen in our study. High diagnostic value of serum ADA in our study suggests that it might be considered as a useful screening tool among the other markers in CLL.

  20. An adenosine nucleoside analogue NITD008 inhibits EV71 proliferation.

    Science.gov (United States)

    Shang, Luqing; Wang, Yaxin; Qing, Jie; Shu, Bo; Cao, Lin; Lou, Zhiyong; Gong, Peng; Sun, Yuna; Yin, Zheng

    2014-12-01

    Enterovirus 71 (EV71), one of the major causative agents of Hand-Foot-Mouth Disease (HFMD), causes severe pandemics and hundreds of deaths in the Asia-Pacific region annually and is an enormous public health threat. However, effective therapeutic antiviral drugs against EV71 are rare. Nucleoside analogues have been successfully used in the clinic for the treatment of various viral infections. We evaluated a total of 27 nucleoside analogues and discovered that an adenosine nucleoside analogue NITD008, which has been reported to be an antiviral reagent that specifically inhibits flaviviruses, effectively suppressed the propagation of different strains of EV71 in RD, 293T and Vero cells with a relatively high selectivity index. Triphosphorylated NITD008 (ppp-NITD008) functions as a chain terminator to directly inhibit the RNA-dependent RNA polymerase activity of EV71, and it does not affect the EV71 VPg uridylylation process. A significant synergistic anti-EV71 effect of NITD008 with rupintrivir (AG7088) (a protease inhibitor) was documented, supporting the potential combination therapy of NITD008 with other inhibitors for the treatment of EV71 infections.

  1. Adenosine deaminase complexing protein (ADCP) immunoreactivity in colorectal adenocarcinoma.

    Science.gov (United States)

    ten Kate, J; van den Ingh, H F; Khan, P M; Bosman, F T

    1986-04-15

    Immunoreactive adenosine deaminase complexing protein (ADCP) was studied in 91 human colorectal adenocarcinomas. The expression of ADCP was correlated with that of secretory component (SC) and carcinoembryonic antigen (CEA), with the histological grade and the Dukes' stage of the carcinomas. The histological grade was scored semi-quantitatively according to 5 structural and 4 cytological variables. ADCP expression was observed in 3 different staining patterns, namely: (1) diffuse cytoplasmic (77% of the carcinomas); (2) granular cytoplasmic (13%); and (3) membrane-associated (66%). These patterns were observed alone or in combination. Eleven percent of the carcinomas exhibited no ADCP immunoreactivity. Linear regression analysis showed that the expression of ADCP correlates with that of SC and CEA. However, no significant correlation emerged between the histological parameters or the Dukes' stage and any of the immunohistological parameters. Comparison of the histological characteristics of carcinomas exhibiting little or no ADCP immunoreactivity with those showing extensive immunoreactivity, showed that membranous ADCP immunoreactivity occurs more frequently in well-differentiated carcinomas. Structural parameters showed a better correlation with membranous ADCP expression than the cytological variables. It is concluded that membranous expression of ADCP and CEA are indicators of a high level of differentiation as reflected primarily in the structural characteristics of the tumor. PMID:3957458

  2. Distribution of adenosine deaminase complexing protein (ADCP) in human tissues.

    Science.gov (United States)

    Dinjens, W N; ten Kate, J; van der Linden, E P; Wijnen, J T; Khan, P M; Bosman, F T

    1989-12-01

    The normal distribution of adenosine deaminase complexing protein (ADCP) in the human body was investigated quantitatively by ADCP-specific radioimmunoassay (RIA) and qualitatively by immunohistochemistry. In these studies we used a specific rabbit anti-human ADCP antiserum. In all 19 investigated tissues, except erythrocytes, ADCP was found by RIA in the soluble and membrane fractions. From all tissues the membrane fractions contained more ADCP (expressed per mg protein) than the soluble fractions. High membrane ADCP concentrations were found in skin, renal cortex, gastrointestinal tract, and prostate. Immunoperoxidase staining confirmed the predominant membrane-associated localization of the protein. In serous sweat glands, convoluted tubules of renal cortex, bile canaliculi, gastrointestinal tract, lung, pancreas, prostate gland, salivary gland, gallbladder, mammary gland, and uterus, ADCP immunoreactivity was found confined to the luminal membranes of the epithelial cells. These data demonstrate that ADCP is present predominantly in exocrine glands and absorptive epithelia. The localization of ADCP at the secretory or absorptive apex of the cells suggests that the function of ADCP is related to the secretory and/or absorptive process. PMID:2573631

  3. Adenosine to Inosine editing frequency controlled by splicing efficiency.

    Science.gov (United States)

    Licht, Konstantin; Kapoor, Utkarsh; Mayrhofer, Elisa; Jantsch, Michael F

    2016-07-27

    Alternative splicing and adenosine to inosine (A to I) RNA-editing are major factors leading to co- and post-transcriptional modification of genetic information. Both, A to I editing and splicing occur in the nucleus. As editing sites are frequently defined by exon-intron basepairing, mRNA splicing efficiency should affect editing levels. Moreover, splicing rates affect nuclear retention and will therefore also influence the exposure of pre-mRNAs to the editing-competent nuclear environment. Here, we systematically test the influence of splice rates on RNA-editing using reporter genes but also endogenous substrates. We demonstrate for the first time that the extent of editing is controlled by splicing kinetics when editing is guided by intronic elements. In contrast, editing sites that are exclusively defined by exonic structures are almost unaffected by the splicing efficiency of nearby introns. In addition, we show that editing levels in pre- and mature mRNAs do not match. This phenomenon can in part be explained by the editing state of an RNA influencing its splicing rate but also by the binding of the editing enzyme ADAR that interferes with splicing. PMID:27112566

  4. Adenosine, type 1 receptors: role in proximal tubule Na+ reabsorption.

    Science.gov (United States)

    Welch, W J

    2015-01-01

    Adenosine type 1 receptor (A1 -AR) antagonists induce diuresis and natriuresis in experimental animals and humans. Much of this effect is due to inhibition of A1 -ARs in the proximal tubule, which is responsible for 60-70% of the reabsorption of filtered Na(+) and fluid. Intratubular application of receptor antagonists indicates that A1 -AR mediates a portion of Na(+) uptake in PT and PT cells, via multiple transport systems, including Na(+) /H(+) exchanger-3 (NHE3), Na(+) /PO4(-) co-transporter and Na(+) -dependent glucose transporter, SGLT. Renal microperfusion and recollection studies have shown that fluid reabsorption is reduced by A1 -AR antagonists and is lower in A1 -AR KO mice, compared to WT mice. Absolute proximal reabsorption (APR) measured by free-flow micropuncture is equivocal, with studies that show either lower APR or similar APR in A1 -AR KO mice, compared to WT mice. Inhibition of A1 -ARs lowers elevated blood pressure in models of salt-sensitive hypertension, partially due to their effects in the proximal tubule. PMID:25345761

  5. In Vitro Functional Study of Rice Adenosine 5'-Phosphosulfate Kinase

    Institute of Scientific and Technical Information of China (English)

    WANG De-zhen; CHEN Guo-guo; LU Lu-jia; JIANG Zhao-jun; RAO Yu-chun; SUN Mei-hao

    2016-01-01

    Sulfate can be activated by ATP sulfurylase and adenosine 5'-phosphosulfate kinase (APSK)in vivo. Recent studies suggested that APSK inArabidopsis thaliana regulated the partition between APS reduction and phosphorylation and its activity can be modulated by cellular redox status. In order to study regulation of APSK in rice (OsAPSK),OsAPSK1 gene was cloned and its activity was analyzed. OsAPSK1 C36 and C69 were found to be the conserved counterparts of C86 and C119, which involved in disulfide formation in AtAPSK.C36A/C69A OsAPSK1 double mutation was made by site directed mutagenesis. OsAPSK1 and its mutant were prokaryotically over-expressed and purified, and then assayed for APS phosphorylation activity. OsAPSK1 activity was depressed by oxidized glutathione, while the activity of its mutantwas not. Further studies in the case that oxidative stress will fluctuatein vivo3'-phosphoadenosine-5'-phosphosulfate content, and all APSK isoenzymes have similar regulation patterns are necessary to be performed.

  6. Cyclic adenosine monophosphate signal pathway in targeted therapy of lymphoma

    Institute of Scientific and Technical Information of China (English)

    DOU Ai-xia; WANG Xin

    2010-01-01

    Objective To review the role of cyclic adenosine monophosphate (cAMP) signal pathway in the pathogenesis oflymphoma and explore a potential lymphoma therapy targeted on this signaling pathway.Data sources The data cited in this review were mainly obtained from the articles listed in Medline and PubMed,published from January 1995 to June 2009. The search terms were "cAMP" and "lymphoma".Study selection Articles regarding the role of the cAMP pathway in apoptosis of lymphoma and associated cells and itspotential role in targeted therapy of lymphoma.Results In the transformation of lymphocytic malignancies, several signal pathways are involved. Among of them, thecAMP pathway has attracted increasing attention because of its apoptosis-inducing role in several lymphoma cells. cAMPpathway impairment is found to influence the prognosis of lymphoma. Targeted therapy to the cAMP pathway seems tobe a new direction for lymphoma treatment, aiming at restoring the cAMP function.Conclusions cAMP signal pathway has different effects on various lymphoma cells. cAMP analogues andphosphodiesterase 4B (PDE4B) inhibitors have potential clinical significance. However, many challenges remain inunderstanding the various roles of such agents.

  7. Feasibility and safety of high-dose adenosine perfusion cardiovascular magnetic resonance

    Directory of Open Access Journals (Sweden)

    Holloway Cameron J

    2010-11-01

    Full Text Available Abstract Introduction Adenosine is the most widely used vasodilator stress agent for Cardiovascular Magnetic Resonance (CMR perfusion studies. With the standard dose of 140 mcg/kg/min some patients fail to demonstrate characteristic haemodynamic changes: a significant increase in heart rate (HR and mild decrease in systolic blood pressure (SBP. Whether an increase in the rate of adenosine infusion would improve peripheral and, likely, coronary vasodilatation in those patients is unknown. The aim of the present study was to assess the tolerance and safety of a high-dose adenosine protocol in patients with inadequate haemodynamic response to the standard adenosine protocol when undergoing CMR perfusion imaging. Methods 98 consecutive patients with known or suspected coronary artery disease (CAD underwent CMR perfusion imaging at 1.5 Tesla. Subjects were screened for contraindications to adenosine, and an electrocardiogram was performed prior to the scan. All patients initially received the standard adenosine protocol (140 mcg/kg/min for at least 3 minutes. If the haemodynamic response was inadequate (HR increase Results All patients successfully completed the CMR scan. Of a total of 98 patients, 18 (18% did not demonstrate evidence of a significant increase in HR or decrease in SBP under the standard adenosine infusion rate. Following the increase in the rate of infusion, 16 out of those 18 patients showed an adequate haemodynamic response. One patient of the standard infusion group and two patients of the high-dose group developed transient advanced AV block. Significantly more patients complained of chest pain in the high-dose group (61% vs. 29%, p = 0.009. On multivariate analysis, age > 65 years and ejection fraction Conclusions A substantial number of patients do not show adequate peripheral haemodynamic response to standard-dose adenosine stress during perfusion CMR imaging. Age and reduced ejection fraction are predictors of inadequate

  8. Characterization of nucleoside triphosphate diphosphohydrolase activity in Trichomonas gallinae and the influence of penicillin and streptomycin in extracellular nucleotide hydrolysis.

    Science.gov (United States)

    Borges, Fernanda Pires; de Brum Vieira, Patrícia; Wiltuschnig, Renata C M; Tasca, Tiana; De Carli, Geraldo Attilio; Bonan, Carla Denise

    2008-06-01

    Here we described an nucleoside triphosphate diphosphohydrolase (NTPDase) activity in living trophozoites of Trichomonas gallinae. The enzyme hydrolyzes a variety of purine and pyrimidine nucleoside di- and triphosphates in an optimum pH range of 6.0-8.0. This enzyme activity was activated by high concentrations of divalent cations, such as calcium and magnesium. Contaminant activities were ruled out because the enzyme was not inhibited by classical inhibitors of ATPases (ouabain, 5.0 mM sodium azide, oligomycin) and alkaline phosphatases (levamisole). A significant inhibition of ATP hydrolysis (38%) was observed in the presence of 20 mM sodium azide. Sodium orthovanadate inhibited ATP and ADP hydrolysis (24% and 78%), respectively. The apparent K(M) (Michaelis constant) values were 667.62+/-13 microM for ATP and 125+/-5.3 microM for ADP. V(max) (maximum velocity) values were 0.44+/-0.007 nmol Pi min(-1) per 10(6) trichomonads and 0.91+/-0.12 nmol Pi min(-1) per 10(6) trichomonads for ATP and ADP, respectively. Moreover, we showed a marked decrease in ATP, ADP and AMP hydrolysis when the parasites were grown in the presence of penicillin and streptomycin. The existence of an NTPDase activity in T. gallinae may be involved in pathogenicity, protecting the parasite from the cytolytic effects of the extracellular nucleotides. PMID:18422631

  9. Crystallization and preliminary X-ray structural analysis of nucleoside triphosphate hydrolases from Neospora caninum and Toxoplasma gondii

    International Nuclear Information System (INIS)

    Recombinant nucleoside triphosphate hydrolases from N. caninum and T. gondii have been purified and crystallized for X-ray structure analysis. The nucleoside triphosphate hydrolases that are produced by Neospora caninum (NcNTPase) and Toxoplasma gondii (TgNTPase-I) have a different physiological function from the ubiquitous ecto-ATPases. The recombinant enzymes were crystallized at 293 K using polyethylene glycol 3350 as a precipitant and X-ray diffraction data sets were collected for NcNTPase (to 2.8 Å resolution) and TgNTPase-I (to 3.1 Å resolution) at 100 K using synchrotron radiation. The crystals of NcNTPase and TgNTPase-I belonged to the orthorhombic space group I222 (unit-cell parameters a = 93.6, b = 140.8, c = 301.1 Å) and the monoclinic space group P21 (unit-cell parameters a = 87.1, b = 123.5, c = 120.2 Å, β = 96.6°), respectively, with two NcNTPase (VM = 3.7 Å3 Da−1) and four TgNTPase-I (VM = 2.7 Å3 Da−1) molecules per asymmetric unit. SAD phasing trials using a data set (λ = 0.97904 Å) collected from a crystal of selenomethionylated NcNTPase gave an initial electron-density map of sufficient quality to build a molecular model of NcNTPase

  10. Adenosine preconditioning attenuates hepatic reperfusion injury in the rat by preventing the down-regulation of endothelial nitric oxide synthase

    Science.gov (United States)

    Serracino-Inglott, Ferdinand; Virlos, Ioannis T; Habib, Nagy A; Williamson, Robin CN; Mathie, Robert T

    2002-01-01

    Background Previous work has suggested that in the liver, adenosine preconditioning is mediated by nitric oxide. Whether the endothelial isoform of nitric oxide synthase plays a part in this mechanism has however not yet been investigated. Methods Wistar rats were used (6 in each group) – Groups: (1) sham, (2) ischemia-reperfusion, (3) adenosine + ischemia-reperfusion, (4) endothelial isoform inhibitor + adenosine + ischemia-reperfusion. Results Using immunohistochemistry, this study has revealed a decrease in the expression of endothelial nitric oxide synthase following hepatic ischemia-reperfusion. This was prevented by adenosine pre-treatment. When an inhibitor of endothelial nitric oxide synthase was administered prior to adenosine pre-treatment, pre-conditioning did not occur despite normal expression of endothelial nitric oxide synthase. Conclusions These findings suggest that adenosine attenuates hepatic injury by preventing the downregulation of endothelial nitric oxide synthase that occurs during ischemia-reperfusion. PMID:12241560

  11. Adenosine elicits an eNOS-independent reduction in arterial blood pressure in conscious mice that involves adenosine A(2A) receptors

    DEFF Research Database (Denmark)

    Andersen, Henrik; Jaff, Mohammad G; Høgh, Ditte;

    2011-01-01

    Aims:  Adenosine plays an important role in the regulation of heart rate and vascular reactivity. However, the mechanisms underlying the acute effect of adenosine on arterial blood pressure in conscious mice are unclear. Therefore, the present study investigated the effect of the nucleoside on mean...... arterial blood pressure (MAP) and heart rate (HR) in conscious mice. Methods:  Chronic indwelling catheters were placed in C57Bl/6J (WT) and endothelial nitric oxide synthase knock-out (eNOS(-/-) ) mice for continuous measurements of MAP and HR. Using PCR and myograph analysis involment of adenosine...... receptors was investigated in human and mouse renal blood vessels Results:  Bolus infusion of 0.5 mg/kg adenosine elicited significant transient decreases in MAP (99.3±2.3 to 70.4±4.5 mmHg) and HR (603.2±18.3 to 364.3±49.2 min(-1) ) which were inhibited by the A(2A) receptor antagonist ZM 241385. Activation...

  12. Chronic hypoxia enhances adenosine release in rat PC12 cells by altering adenosine metabolism and membrane transport.

    Science.gov (United States)

    Kobayashi, S; Zimmermann, H; Millhorn, D E

    2000-02-01

    Acute exposure to hypoxia causes a release of adenosine (ADO) that is inversely related to the O2 levels in oxygen-sensitive pheochromocytoma (PC12) cells. In the current study, chronic exposure (48 h) of PC12 cells to moderate hypoxia (5% O2) significantly enhanced the release of ADO during severe, acute hypoxia (1% O2). Investigation into the intra- and extracellular mechanisms underpinning the secretion of ADO in PC12 cells chronically exposed to hypoxia revealed changes in gene expression and activities of several key enzymes associated with ADO production and metabolism, as well as the down-regulation of a nucleoside transporter. Decreases in the enzymatic activities of ADO kinase and ADO deaminase accompanied by an increase in those of cytoplasmic and ecto-5'-nucleotidases bring about an increased capacity to produce intra- and extracellular ADO. This increased potential to generate ADO and decreased capacity to metabolize ADO indicate that PC12 cells shift toward an ADO producer phenotype during hypoxia. The reduced function of the rat equilibrative nucleoside transporter rENT1 also plays a role in controlling extracellular ADO levels. The hypoxia-induced alterations in the ADO metabolic enzymes and the rENT1 transporter seem to increase the extracellular concentration of ADO. The biological significance of this regulation is unclear but is likely to be associated with modulating cellular activity during hypoxia. PMID:10646513

  13. Comparative study of adenosine deaminase activity, insulin resistance and lipoprotein(a) among smokers and healthy non-smokers

    OpenAIRE

    Ramesh Ramasamy; Sathish Babu Murugaiyan; Arulkumaran U.; Sathiya R.; Kuzhandai Velu V.; Niranjan Gopal

    2016-01-01

    Background: Adenosine deaminase also known as adenosine aminohydrolase involved in purine metabolism. Its primary function is development and maintenance of immune system. The main objective of the study was to estimate adenosine deaminase (ADA) enzyme and find its correlation with lipoprotein(a) and insulin resistance among smokers and healthy non-smokers. Methods: Fifty smokers and fifty healthy non-smokers were selected based on WHO definition. ADA, lipid profile and glucose was estimat...

  14. Sleep-wake sensitive mechanisms of adenosine release in the basal forebrain of rodents: an in vitro study.

    Directory of Open Access Journals (Sweden)

    Robert Edward Sims

    Full Text Available Adenosine acting in the basal forebrain is a key mediator of sleep homeostasis. Extracellular adenosine concentrations increase during wakefulness, especially during prolonged wakefulness and lead to increased sleep pressure and subsequent rebound sleep. The release of endogenous adenosine during the sleep-wake cycle has mainly been studied in vivo with microdialysis techniques. The biochemical changes that accompany sleep-wake status may be preserved in vitro. We have therefore used adenosine-sensitive biosensors in slices of the basal forebrain (BFB to study both depolarization-evoked adenosine release and the steady state adenosine tone in rats, mice and hamsters. Adenosine release was evoked by high K(+, AMPA, NMDA and mGlu receptor agonists, but not by other transmitters associated with wakefulness such as orexin, histamine or neurotensin. Evoked and basal adenosine release in the BFB in vitro exhibited three key features: the magnitude of each varied systematically with the diurnal time at which the animal was sacrificed; sleep deprivation prior to sacrifice greatly increased both evoked adenosine release and the basal tone; and the enhancement of evoked adenosine release and basal tone resulting from sleep deprivation was reversed by the inducible nitric oxide synthase (iNOS inhibitor, 1400 W. These data indicate that characteristics of adenosine release recorded in the BFB in vitro reflect those that have been linked in vivo to the homeostatic control of sleep. Our results provide methodologically independent support for a key role for induction of iNOS as a trigger for enhanced adenosine release following sleep deprivation and suggest that this induction may constitute a biochemical memory of this state.

  15. Adenosine deaminase regulates Treg expression in autologous T cell-dendritic cell cocultures from patients infected with HIV-1.

    Science.gov (United States)

    Naval-Macabuhay, Isaac; Casanova, Víctor; Navarro, Gemma; García, Felipe; León, Agathe; Miralles, Laia; Rovira, Cristina; Martinez-Navio, José M; Gallart, Teresa; Mallol, Josefa; Gatell, José M; Lluís, Carme; Franco, Rafael; McCormick, Peter J; Climent, Núria

    2016-02-01

    Regulatory T cells have an important role in immune suppression during HIV-1 infection. As regulatory T cells produce the immunomodulatory molecule adenosine, our aim here was to assess the potential of adenosine removal to revert the suppression of anti-HIV responses exerted by regulatory T cells. The experimental setup consisted of ex vivo cocultures of T and dendritic cells, to which adenosine deaminase, an enzyme that hydrolyzes adenosine, was added. In cells from healthy individuals, adenosine hydrolysis decreased CD4(+)CD25(hi) regulatory T cells. Addition of 5'-N-ethylcarboxamidoadenosine, an adenosine receptor agonist, significantly decreased CD4(+)CD25(lo) cells, confirming a modulatory role of adenosine acting via adenosine receptors. In autologous cocultures of T cells with HIV-1-pulsed dendritic cells, addition of adenosine deaminase led to a significant decrease of HIV-1-induced CD4(+)CD25(hi) forkhead box p3(+) cells and to a significant enhancement of the HIV-1-specific CD4(+) responder T cells. An increase in the effector response was confirmed by the enhanced production of CD4(+) and CD8(+) CD25(-)CD45RO(+) memory cell generation and secretion of Th1 cytokines, including IFN-γ and IL-15 and chemokines MIP-1α/CCL3, MIP-1β/CCL4, and RANTES/CCL5. These ex vivo results show, in a physiologically relevant model, that adenosine deaminase is able to enhance HIV-1 effector responses markedly. The possibility to revert regulatory T cell-mediated inhibition of immune responses by use of adenosine deaminase, an enzyme that hydrolyzes adenosine, merits attention for restoring T lymphocyte function in HIV-1 infection. PMID:26310829

  16. A2A adenosine receptor-mediated increase in coronary flow in hyperlipidemic APOE–knockout mice

    OpenAIRE

    Teng, Bunyen

    2011-01-01

    Bunyen Teng, S Jamal MustafaDepartment of Physiology and Pharmacology and Center for Cardiovascular and Respiratory Sciences, West Virginia University, Morgantown, WV, USAAbstract: Adenosine-induced coronary vasodilation is predominantly A2A adenosine receptor (AR)-mediated, whereas A1 AR is known to negatively modulate the coronary flow (CF). However, the coronary responses to adenosine in hyperlipidemia and atherosclerosis are not well understood. Using hyperlipidemic/atherosclerotic apolip...

  17. In vivo adenosine A(2B) receptor desensitization in guinea-pig airway smooth muscle: implications for asthma.

    Science.gov (United States)

    Breschi, Maria Cristina; Blandizzi, Corrado; Fogli, Stefano; Martinelli, Cinzia; Adinolfi, Barbara; Calderone, Vincenzo; Camici, Marcella; Martinotti, Enrica; Nieri, Paola

    2007-12-01

    This study was aimed at characterizing the role of adenosine receptor subtypes in the contractility modulation of guinea-pig airway smooth muscle in normal and pathological settings. In vitro and in vivo experiments were performed by testing selective agonists and antagonists on isolated tracheal smooth muscle preparations and pulmonary inflation pressure, respectively, under normal conditions or following ovalbumin-induced allergic sensitization. In normal and sensitized animals, the adenosine A(2A)/A(2B) receptor agonist, NECA, evoked relaxing responses of isolated tracheal preparations precontracted with histamine, and such an effect was reversed by the adenosine A(2B) antagonist, MRS 1706, in the presence or in the absence of epithelium. The expression of mRNA coding for adenosine A(2B) receptors was demonstrated in tracheal specimens. In vitro desensitization with 100 microM NECA markedly reduced the relaxing effect of the agonist. In vivo NECA or adenosine administration to normal animals inhibited histamine-mediated bronchoconstriction, while these inhibitory effects no longer occurred in sensitized guinea-pigs. Adenosine plasma levels were significantly higher in sensitized than normal animals. In conclusion, our data demonstrate that: (i) adenosine A(2B) receptors are responsible for the relaxing effects of adenosine on guinea-pig airways; (ii) these receptors can undergo rapid adaptive changes that may affect airway smooth muscle responsiveness to adenosine; (iii) ovalbumin-induced sensitization promotes a reversible inactivation of adenosine A(2B) receptors which can be ascribed to homologous desensitization. These findings can be relevant to better understand adenosine functions in airways as well as mechanisms of action of asthma therapies targeting the adenosine system.

  18. Ion-Pairing Liquid Chromatography Coupled with Mass Spectrometry for the Simultaneous Determination of Nucleosides and Nucleotides%离子对液相色谱-质谱应用于核苷和核苷酸的同时测定

    Institute of Scientific and Technical Information of China (English)

    蔡宗苇; 钱天秀; 杨斯敏

    2004-01-01

    Adenosine and its corresponding nucleotides adenosine 5'-monophosphate (AMP), adenosine 5'-diphosphate ( ADP ) and adenosine 5'-triphos-phate (ATP) are important biomolecules that provide energy and substrates for various cellular bio-chemical processes. There have been strong

  19. Adenosine enhances sweet taste through A2B receptors in the taste bud.

    Science.gov (United States)

    Dando, Robin; Dvoryanchikov, Gennady; Pereira, Elizabeth; Chaudhari, Nirupa; Roper, Stephen D

    2012-01-01

    Mammalian taste buds use ATP as a neurotransmitter. Taste Receptor (type II) cells secrete ATP via gap junction hemichannels into the narrow extracellular spaces within a taste bud. This ATP excites primary sensory afferent fibers and also stimulates neighboring taste bud cells. Here we show that extracellular ATP is enzymatically degraded to adenosine within mouse vallate taste buds and that this nucleoside acts as an autocrine neuromodulator to selectively enhance sweet taste. In Receptor cells in a lingual slice preparation, Ca(2+) mobilization evoked by focally applied artificial sweeteners was significantly enhanced by adenosine (50 μM). Adenosine had no effect on bitter or umami taste responses, and the nucleoside did not affect Presynaptic (type III) taste cells. We also used biosensor cells to measure transmitter release from isolated taste buds. Adenosine (5 μM) enhanced ATP release evoked by sweet but not bitter taste stimuli. Using single-cell reverse transcriptase (RT)-PCR on isolated vallate taste cells, we show that many Receptor cells express the adenosine receptor, Adora2b, while Presynaptic (type III) and Glial-like (type I) cells seldom do. Furthermore, Adora2b receptors are significantly associated with expression of the sweet taste receptor subunit, Tas1r2. Adenosine is generated during taste stimulation mainly by the action of the ecto-5'-nucleotidase, NT5E, and to a lesser extent, prostatic acid phosphatase. Both these ecto-nucleotidases are expressed by Presynaptic cells, as shown by single-cell RT-PCR, enzyme histochemistry, and immunofluorescence. Our findings suggest that ATP released during taste reception is degraded to adenosine to exert positive modulation particularly on sweet taste.

  20. Three minute versus six minute adenosine infusion in myocardial perfusion scintigraphy

    International Nuclear Information System (INIS)

    Pharmacological stress imaging techniques are used widely in clinical nuclear cardiology for evaluation of ischemic heart disease. Adenosine is often used but is expensive and causes significant side effects .The aim of this retrospective review was to study the tolerance and efficacy, of adenosine infusion of a 3 minute (min) versus the conventional 6 min stress protocol and to assess the cost efficiency of the 3 min protocol. Three hundred thirty one patients had myocardial scintigraphy using adenosine as a stressing agent. Blood pressure, heart rate and ECG were recorded at baseline and during the test. Symptoms (flushing, headache, chest pain, dyspnoea, neck pain) were recorded throughout the adenosine infusion. All the patients had had either 6 min or 3 min adenosine infusion at 140 mg/kg per minute. 169 of them had side effects. Flushing (32% at 3 min vs 50 % at 6 min, p<0.05), headache (11.5% at 3 min vs 7 % at 6 min p-not significant-ns), chest pain (8% at 3 min vs 13 % at 6 min, ns), dyspnoea (7% at 3 min vs %10 at 6 min, ns), ECG changes (10% at 3 min vs 28% at 6 min, p<0.05), neck pain (4.5% at 3 min vs 9% at 6 min, ns), abdominal discomfort (3% at 3 min vs 3% at 6 min, ns) and fall in blood pressure (6% at 3 min vs 8.5% at 6 min, ns). The change in heart rate was not significant with either protocol. The 6 min and 3 min infusions of adenosine had similar accuracy (73% vs 70%) for the detection of coronary artery disease. The patients tolerated the 3 min protocol better with only 40% of the patients having minimal side effects compared with 60% for the 6 mon protocol. The 3 min protocol is also cost effective as it uses less adenosine and therefore reduces total costs by 40 US$ per patient. (author)

  1. Impairment of ATP hydrolysis decreases adenosine A1 receptor tonus favoring cholinergic nerve hyperactivity in the obstructed human urinary bladder.

    Science.gov (United States)

    Silva-Ramos, M; Silva, I; Faria, M; Magalhães-Cardoso, M T; Correia, J; Ferreirinha, F; Correia-de-Sá, P

    2015-12-01

    This study was designed to investigate whether reduced adenosine formation linked to deficits in extracellular ATP hydrolysis by NTPDases contributes to detrusor neuromodulatory changes associated with bladder outlet obstruction in men with benign prostatic hyperplasia (BPH). The kinetics of ATP catabolism and adenosine formation as well as the role of P1 receptor agonists on muscle tension and nerve-evoked [(3)H]ACh release were evaluated in mucosal-denuded detrusor strips from BPH patients (n = 31) and control organ donors (n = 23). The neurogenic release of ATP and [(3)H]ACh was higher (P bladders. Relaxation of detrusor contractions induced by acetylcholine required 30-fold higher concentrations of adenosine. Despite VAChT-positive cholinergic nerves exhibiting higher A(1) immunoreactivity in BPH bladders, the endogenous adenosine tonus revealed by adenosine deaminase is missing. Restoration of A1 inhibition was achieved by favoring (1) ATP hydrolysis with apyrase (2 U mL(-1)) or (2) extracellular adenosine accumulation with dipyridamole or EHNA, as these drugs inhibit adenosine uptake and deamination, respectively. In conclusion, reduced ATP hydrolysis leads to deficient adenosine formation and A(1) receptor-mediated inhibition of cholinergic nerve activity in the obstructed human bladder. Thus, we propose that pharmacological manipulation of endogenous adenosine levels and/or A(1) receptor activation might be useful to control bladder overactivity in BPH patients. PMID:26521170

  2. Rapid tolerance against focal cerebral ischemia induced by isoflurane anesthesia is attenuated by adenosine A1 receptor antagonist in rats

    Institute of Scientific and Technical Information of China (English)

    刘艳红; 熊利泽

    2003-01-01

    The brief anesthesia with isoflurane induces rapid tolerance against focal cerebral ischemia in rats and adenosine A1 receptor antagonist, DPCPX, attenuates the beneficial effect of isoflurane preconditioning.

  3. CSF ADENOSINE DEAMINASE (ADA ACTIVITY IN PATIENTS WITH MENINGITIS

    Directory of Open Access Journals (Sweden)

    Justin

    2016-05-01

    Full Text Available Meningitis is inflammation of the meninges (pia, arachnoid and dura mater covering the brain and the spinal cord. ADA is an enzyme in the purine salvage pathway which is found in abundance in active T-lymphocytes. Hence, an attempt was made to estimate the CSF ADA level in patients with suspected meningitis and throw light on its use in differentiating the various types of meningitis. AIMS AND OBJECTIVES To estimate the level of CSF adenosine deaminase level in different types of meningitis. To assess its usefulness in differentiating the various types (bacterial, viral and tuberculous of meningitis. MATERIALS AND METHODS The study was conducted at the medical wards of Govt. Rajaji Hospital, Madurai, a prospective analytical study from a period of April 2012 to September 2012. OBSERVATION AND RESULTS Tuberculous meningitis occurred more in the age group of 21–40 years. Bacterial meningitis was seen mainly in patients < 20 years of age. Viral meningitis was seen in all age groups. CSF ADA level was highest in tuberculous meningitis, the mean value being 24.5 U/L. The mean value of ADA in bacterial meningitis was 4.54 U/L and viral meningitis patients had lowest mean ADA value of 2.65 U/L. CONCLUSION In our study, 50 patients with meningitis admitted in Government Rajaji Hospital from April 2012 to September 2012 were evaluated. Meningitis predominantly affected people in the age group of 20-40 years in our study with a male: female ratio of 1.9:1. Cases of tuberculous meningitis constituted 48% of the study group and bacterial and viral meningitis were 26% each. CSF protein values were higher and sugar values lower in patients with tuberculous and bacterial meningitis. CSF cell counts were higher in patients with bacterial meningitis.

  4. Biochemistry of an olfactory purinergic system: dephosphorylation of excitatory nucleotides and uptake of adenosine

    Energy Technology Data Exchange (ETDEWEB)

    Trapido-Rosenthal, H.G.; Carr, W.E.; Gleeson, R.A.

    1987-10-01

    The olfactory organ of the spiny lobster, Panulirus argus, is composed of chemosensory sensilla containing the dendrites of primary chemosensory neurons. Receptors on these dendrites are activated by the nucleotides AMP, ADP, and ATP but not by the nucleoside adenosine. It is shown here that the lobster chemosensory sensilla contain enzymes that dephosphorylate excitatory nucleotides and an uptake system that internalizes the nonexcitatory dephosphorylated product adenosine. The uptake of (/sup 3/H)-adenosine is saturable with increasing concentration, linear with time for up to 3 h, sodium dependent, insensitive to moderate pH changes and has a Km of 7.1 microM and a Vmax of 5.2 fmol/sensillum/min (573 fmol/micrograms of protein/min). Double-label experiments show that sensilla dephosphorylate nucleotides extracellularly; /sup 3/H from adenine-labeled AMP or ATP is internalized, whereas 32P from phosphate-labeled nucleotides is not. The dephosphorylation of AMP is very rapid; /sup 3/H from AMP is internalized at the same rate as /sup 3/H from adenosine. Sensillar 5'-ectonucleotidase activity is inhibited by ADP and the ADP analog alpha, beta-methylene ADP. Collectively, these results indicate that the enzymes and the uptake system whereby chemosensory sensilla of the lobster inactivate excitatory nucleotides and clear adenosine from extracellular spaces are very similar to those present in the internal tissues of vertebrates, where nucleotides have many neuroactive effects.

  5. Comparative transcriptome analysis of Bacillus subtilis responding to dissolved oxygen in adenosine fermentation.

    Directory of Open Access Journals (Sweden)

    Wen-Bang Yu

    Full Text Available Dissolved oxygen (DO is an important factor for adenosine fermentation. Our previous experiments have shown that low oxygen supply in the growth period was optimal for high adenosine yield. Herein, to better understand the link between oxygen supply and adenosine productivity in B. subtilis (ATCC21616, we sought to systematically explore the effect of DO on genetic regulation and metabolism through transcriptome analysis. The microarrays representing 4,106 genes were used to study temporal transcript profiles of B. subtilis fermentation in response to high oxygen supply (agitation 700 r/min and low oxygen supply (agitation 450 r/min. The transcriptome data analysis revealed that low oxygen supply has three major effects on metabolism: enhance carbon metabolism (glucose metabolism, pyruvate metabolism and carbon overflow, inhibit degradation of nitrogen sources (glutamate family amino acids and xanthine and purine synthesis. Inhibition of xanthine degradation was the reason that low oxygen supply enhanced adenosine production. These provide us with potential targets, which can be modified to achieve higher adenosine yield. Expression of genes involved in energy, cell type differentiation, protein synthesis was also influenced by oxygen supply. These results provided new insights into the relationship between oxygen supply and metabolism.

  6. Aberrant bone density in aging mice lacking the adenosine transporter ENT1.

    Directory of Open Access Journals (Sweden)

    David J Hinton

    Full Text Available Adenosine is known to regulate bone production and resorption in humans and mice. Type 1 equilibrative nucleoside transporter (ENT1 is responsible for the majority of adenosine transport across the plasma membrane and is ubiquitously expressed in both humans and mice. However, the contribution of ENT1-mediated adenosine levels has not been studied in bone remodeling. With the recent identification of the importance of adenosine signaling in bone homeostasis, it is essential to understand the role of ENT1 to develop novel therapeutic compounds for bone disorders. Here we examined the effect of ENT1 deletion on bone density using X-ray, dual energy X-ray absorptiometry and micro-computerized tomography analysis. Our results show that bone density and bone mineral density is reduced in the lower thoracic and lumbar spine as well as the femur of old ENT1 null mice (>7 months compared to wild-type littermates. Furthermore, we found increased mRNA expression of tartrate-resistant acid phosphatase (TRAP, an osteoclast marker, in isolated long bones from 10 month old ENT1 null mice compared to wild-type mice. In addition, aged ENT1 null mice displayed severe deficit in motor coordination and locomotor activity, which might be attributed to dysregulated bone density. Overall, our study suggests that ENT1-regulated adenosine signaling plays an essential role in lumbar spine and femur bone density.

  7. Clofarabine 5′-di and -triphosphates inhibit human ribonucleotide reductase by altering the quaternary structure of its large subunit

    OpenAIRE

    Aye, Yimon; Stubbe, JoAnne

    2011-01-01

    Human ribonucleotide reductases (hRNRs) catalyze the conversion of nucleotides to deoxynucleotides and are composed of α- and β-subunits that form active αnβm (n, m = 2 or 6) complexes. α binds NDP substrates (CDP, UDP, ADP, and GDP, C site) as well as ATP and dNTPs (dATP, dGTP, TTP) allosteric effectors that control enzyme activity (A site) and substrate specificity (S site). Clofarabine (ClF), an adenosine analog, is used in the treatment of refractory leukemias. Its mode of cytotoxicity is...

  8. The adenosine A2B receptor is involved in anion secretion in human pancreatic duct Capan-1 epithelial cells.

    Science.gov (United States)

    Hayashi, M; Inagaki, A; Novak, I; Matsuda, H

    2016-07-01

    Adenosine modulates a wide variety of biological processes via adenosine receptors. In the exocrine pancreas, adenosine regulates transepithelial anion secretion in duct cells and is considered to play a role in acini-to-duct signaling. To identify the functional adenosine receptors and Cl(-) channels important for anion secretion, we herein performed experiments on Capan-1, a human pancreatic duct cell line, using open-circuit Ussing chamber and gramicidin-perforated patch-clamp techniques. The luminal addition of adenosine increased the negative transepithelial potential difference (V te) in Capan-1 monolayers with a half-maximal effective concentration value of approximately 10 μM, which corresponded to the value obtained on whole-cell Cl(-) currents in Capan-1 single cells. The effects of adenosine on V te, an equivalent short-circuit current (I sc), and whole-cell Cl(-) currents were inhibited by CFTRinh-172, a cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel inhibitor. The adenosine A2B receptor agonist, BAY 60-6583, increased I sc and whole-cell Cl(-) currents through CFTR Cl(-) channels, whereas the A2A receptor agonist, CGS 21680, had negligible effects. The A2B receptor antagonist, PSB 603, inhibited the response of I sc to adenosine. Immunohistochemical analysis showed that the A2A and A2B receptors colocalized with Ezrin in the luminal membranes of Capan-1 monolayers and in rat pancreatic ducts. Adenosine elicited the whole-cell Cl(-) currents in guinea pig duct cells. These results demonstrate that luminal adenosine regulates anion secretion by activating CFTR Cl(-) channels via adenosine A2B receptors on the luminal membranes of Capan-1 cells. The present study endorses that purinergic signaling is important in the regulation of pancreatic secretion. PMID:26965147

  9. An Escherichia coli strain deficient for both exonuclease V and deoxycytidine triphosphate deaminase shows enhanced sensitivity to ionizing radiation.

    Science.gov (United States)

    Estèvenon, A M; Kooistra, J; Sicard, N

    1995-02-20

    An Escherichia coli mutant lacking deoxycytidine triphosphate deaminase (Dcd) activity and an unknown function encoded by a gene designated ior exhibits sensitivity to ionizing radiation whereas dcd mutants themselves are not sensitive. A DNA fragment from an E. coli genomic library that restores the wild type level of UV and gamma ray resistance to this mutant has been cloned in the multicopy vector pBR322. Comparison of its restriction map with the physical map of the E. coli chromosome revealed complete identity to the recBD genes. ior affects ATP-dependent exonuclease activity, suggesting that it is an allele of recB. This mutation alone does not confer sensitivity to UV and gamma radiation, indicating that lack of Dcd activity is also required for expression of radiation sensitivity.

  10. Crystal Structure of a Legionella pneumophila Ecto -Triphosphate Diphosphohydrolase, A Structural and Functional Homolog of the Eukaryotic NTPDases

    Energy Technology Data Exchange (ETDEWEB)

    Vivian, Julian P.; Riedmaier, Patrice; Ge, Honghua; Le Nours, Jérôme; Sansom, Fiona M.; Wilce, Matthew C.J.; Byres, Emma; Dias, Manisha; Schmidberger, Jason W.; Cowan, Peter J.; d' Apice, Anthony J.F.; Hartland, Elizabeth L.; Rossjohn, Jamie; Beddoe, Travis (Monash); (Melbourne)

    2010-04-19

    Many pathogenic bacteria have sophisticated mechanisms to interfere with the mammalian immune response. These include the disruption of host extracellular ATP levels that, in humans, is tightly regulated by the nucleoside triphosphate diphosphohydrolase family (NTPDases). NTPDases are found almost exclusively in eukaryotes, the notable exception being their presence in some pathogenic prokaryotes. To address the function of bacterial NTPDases, we describe the structures of an NTPDase from the pathogen Legionella pneumophila (Lpg1905/Lp1NTPDase) in its apo state and in complex with the ATP analog AMPPNP and the subtype-specific NTPDase inhibitor ARL 67156. Lp1NTPDase is structurally and catalytically related to eukaryotic NTPDases and the structure provides a basis for NTPDase-specific inhibition. Furthermore, we demonstrate that the activity of Lp1NTPDase correlates directly with intracellular replication of Legionella within macrophages. Collectively, these findings provide insight into the mechanism of this enzyme and highlight its role in host-pathogen interactions.

  11. Role of adenosine in the antiepileptic effects of deep brain stimulation

    Science.gov (United States)

    Miranda, Maisa F.; Hamani, Clement; de Almeida, Antônio-Carlos G.; Amorim, Beatriz O.; Macedo, Carlos E.; Fernandes, Maria José S.; Nobrega, José N.; Aarão, Mayra C.; Madureira, Ana Paula; Rodrigues, Antônio M.; Andersen, Monica L.; Tufik, Sergio; Mello, Luiz E.; Covolan, Luciene

    2014-01-01

    Despite the effectiveness of anterior thalamic nucleus (AN) deep brain stimulation (DBS) for the treatment of epilepsy, mechanisms responsible for the antiepileptic effects of this therapy remain elusive. As adenosine modulates neuronal excitability and seizure activity in animal models, we hypothesized that this nucleoside could be one of the substrates involved in the effects of AN DBS. We applied 5 days of stimulation to rats rendered chronically epileptic by pilocarpine injections and recorded epileptiform activity in hippocampal slices. We found that slices from animals given DBS had reduced hippocampal excitability and were less susceptible to develop ictal activity. In live animals, AN DBS significantly increased adenosine levels in the hippocampus as measured by microdialysis. The reduced excitability of DBS in vitro was completely abolished in animals pre-treated with A1 receptor antagonists and was strongly potentiated by A1 receptor agonists. We conclude that some of the antiepileptic effects of DBS may be mediated by adenosine. PMID:25324724

  12. Downregulation of adenosine and P2X receptor-mediated cardiovascular responses in heart failure rats

    DEFF Research Database (Denmark)

    Zhao, Xin; Sun, X Y; Erlinge, D;

    2000-01-01

    Neurohormonal changes in congestive heart failure (CHF) include an enhanced peripheral sympathetic nerve activity which results in increased release of noradrenaline, neuropeptide Y and ATP. To examine if such changes in CHF would modulate peripheral pre- and postsynaptic receptors of ATP and its...... effects mediated by the endothelial P2Y receptors are unaffected in CHF. Moreover, the adenosine-mediated inhibitory effects on heart rate and blood pressure were also attenuated in the CHF rats. The most important changes in adenosine and P2-receptor function induced by ischaemic CHF were the reduced...... pressor effect mediated by the P2X receptor and the increased heart rate due to an attenuated inhibitory effect of adenosine....

  13. AN ESCHERICHIA-COLI STRAIN DEFICIENT FOR BOTH EXONUCLEASE-V AND DEOXYCYTIDINE TRIPHOSPHATE DEAMINASE SHOWS ENHANCED SENSITIVITY TO IONIZING-RADIATION

    NARCIS (Netherlands)

    ESTEVENON, AM; KOOISTRA, J; SICARD, N

    1995-01-01

    An Escherichia coli mutant lacking deoxycytidine triphosphate deaminase (Dcd) activity and an unknown function encoded by a gene designated ior exhibits sensitivity to ionizing radiation whereas dcd mutants themselves are not sensitive. A DNA fragment from an E. coli genomic library that restores th

  14. Magnetically assisted fluorescence ratiometric assays for adenosine deaminase using water-soluble conjusated polymers

    Institute of Scientific and Technical Information of China (English)

    HE Fang; YU MingHui; WANG Shu

    2009-01-01

    A magnetically assisted fluorescence ratiometric technique has been developed for adenosine deami-nase assays with high sensitivity using water-soluble cationic conjugated polymers (CCPs).The assay contains three elements:a biotin-labeled aptamer of adenosine (biotin-aptamer),a signaling probe single-stranded DNA-tagged fiuorescein at terminus (ssDNA-FI) and a CCP.The specific binding of adenosine to biotin-aptamer makes biotin-aptamer and ssDNA-FI unhybridized,and the ssDNA-FI is washed out after streptavidin-coated magnetic beads are added and separated from the assay solution under magnetic field.In this case,after the addition of CCP to the magnetic beads solution,the fluo-rescence resonance energy transfer (FRET) from CCP to fluorescein is inefficient.Upon adding adenosine deaminase,the adenosine is converted into inosine,and the biotin-aptamer is hybridized with ssDNA-FI to form doubled stranded DNA (biotin-dsDNA-FI).The ssONA-FI is attached to the mag-netic beads at the separation step,and the addition of CCP to the magnetic beads solution leads to efficient FRET from CCP to fluorescein.Thus the adenosine deaminase activity can be monitored by fluorescence spectra in view of the intensity decrease of CCP emission or the increase of fluorescein emission in aqueous solutions.The assay integrates surface-functionalized magnetic particles with significant amplification of detection signal of water-soluble cationic conjugated polymers.

  15. 2'-O methylation of internal adenosine by flavivirus NS5 methyltransferase.

    Directory of Open Access Journals (Sweden)

    Hongping Dong

    Full Text Available RNA modification plays an important role in modulating host-pathogen interaction. Flavivirus NS5 protein encodes N-7 and 2'-O methyltransferase activities that are required for the formation of 5' type I cap (m(7GpppAm of viral RNA genome. Here we reported, for the first time, that flavivirus NS5 has a novel internal RNA methylation activity. Recombinant NS5 proteins of West Nile virus and Dengue virus (serotype 4; DENV-4 specifically methylates polyA, but not polyG, polyC, or polyU, indicating that the methylation occurs at adenosine residue. RNAs with internal adenosines substituted with 2'-O-methyladenosines are not active substrates for internal methylation, whereas RNAs with adenosines substituted with N⁶-methyladenosines can be efficiently methylated, suggesting that the internal methylation occurs at the 2'-OH position of adenosine. Mass spectroscopic analysis further demonstrated that the internal methylation product is 2'-O-methyladenosine. Importantly, genomic RNA purified from DENV virion contains 2'-O-methyladenosine. The 2'-O methylation of internal adenosine does not require specific RNA sequence since recombinant methyltransferase of DENV-4 can efficiently methylate RNAs spanning different regions of viral genome, host ribosomal RNAs, and polyA. Structure-based mutagenesis results indicate that K61-D146-K181-E217 tetrad of DENV-4 methyltransferase forms the active site of internal methylation activity; in addition, distinct residues within the methyl donor (S-adenosyl-L-methionine pocket, GTP pocket, and RNA-binding site are critical for the internal methylation activity. Functional analysis using flavivirus replicon and genome-length RNAs showed that internal methylation attenuated viral RNA translation and replication. Polymerase assay revealed that internal 2'-O-methyladenosine reduces the efficiency of RNA elongation. Collectively, our results demonstrate that flavivirus NS5 performs 2'-O methylation of internal adenosine of

  16. Adenosine receptor antagonists alter the stability of human epileptic GABAA receptors

    Science.gov (United States)

    Roseti, Cristina; Martinello, Katiuscia; Fucile, Sergio; Piccari, Vanessa; Mascia, Addolorata; Di Gennaro, Giancarlo; Quarato, Pier Paolo; Manfredi, Mario; Esposito, Vincenzo; Cantore, Gianpaolo; Arcella, Antonella; Simonato, Michele; Fredholm, Bertil B.; Limatola, Cristina; Miledi, Ricardo; Eusebi, Fabrizio

    2008-01-01

    We examined how the endogenous anticonvulsant adenosine might influence γ-aminobutyric acid type A (GABAA) receptor stability and which adenosine receptors (ARs) were involved. Upon repetitive activation (GABA 500 μM), GABAA receptors, microtransplanted into Xenopus oocytes from neurosurgically resected epileptic human nervous tissues, exhibited an obvious GABAA-current (IGABA) run-down, which was consistently and significantly reduced by treatment with the nonselective adenosine receptor antagonist CGS15943 (100 nM) or with adenosine deaminase (ADA) (1 units/ml), that inactivates adenosine. It was also found that selective antagonists of A2B (MRS1706, 10 nM) or A3 (MRS1334, 30 nM) receptors reduced IGABA run-down, whereas treatment with the specific A1 receptor antagonist DPCPX (10 nM) was ineffective. The selective A2A receptor antagonist SCH58261 (10 nM) reduced or potentiated IGABA run-down in ≈40% and ≈20% of tested oocytes, respectively. The ADA-resistant, AR agonist 2-chloroadenosine (2-CA) (10 μM) potentiated IGABA run-down but only in ≈20% of tested oocytes. CGS15943 administration again decreased IGABA run-down in patch-clamped neurons from either human or rat neocortex slices. IGABA run-down in pyramidal neurons was equivalent in A1 receptor-deficient and wt neurons but much larger in neurons from A2A receptor-deficient mice, indicating that, in mouse cortex, GABAA-receptor stability is tonically influenced by A2A but not by A1 receptors. IGABA run-down from wt mice was not affected by 2-CA, suggesting maximal ARs activity by endogenous adenosine. Our findings strongly suggest that cortical A2–A3 receptors alter the stability of GABAA receptors, which could offer therapeutic opportunities. PMID:18809912

  17. Caffeine's Attenuation of Cocaine-Induced Dopamine Release by Inhibition of Adenosine.

    Science.gov (United States)

    Malave, Lauren B; Broderick, Patricia A

    2014-06-01

    Background: It is well known that the reinforcing properties of cocaine addiction are caused by the sharp increase of dopamine (DA) in the reward areas of the brain. However, other mechanisms have been speculated to contribute to the increase. Adenosine is one system that is associated with the sleep-wake cycle and is most important in regulating neuronal activity. Thus, more and more evidence is pointing to its involvement in regulating DA release. The current study set out to examine the role of adenosine in cocaine-induced DA release. Methods: Increasing doses of cocaine, caffeine, and their combination, as well as, 8-cyclopentyltheophylline (CPT), an adenosine A1 antagonist (alone and in combination with cocaine) were used to denote a response curve. A novel biosensor, the BRODERICK PROBE(®) was implanted in the nucleus accumbens to image the drug-induced surge of DA release in vivo, in the freely moving animal in real time. Results: Combinations of cocaine and caffeine were observed to block the increased release of DA moderately after administration of the low dose (2.5 mg/kg cocaine and 12.5 mg/kg caffeine) and dramatically after administration of the high dose (10 mg/kg cocaine and 50 mg/kg caffeine), suggesting neuroprotection. Similarly, CPT and cocaine showed a decreased DA surge when administered in combination. Thus, the low and high dose of a nonselective adenosine antagonist, caffeine, and a moderate dose of a selective adenosine antagonist, CPT, protected against the cocaine-induced DA release. Conclusions: These results show a significant interaction between adenosine and DA release and suggest therapeutic options for cocaine addiction and disorders associated with DA dysfunction. PMID:25054079

  18. Plasma concentrations of the cyclic nucleotides, adenosine 3',5'-monophosphate and guanosine 3'.5'-monophosphate, in healthy adults treated with theophylline

    DEFF Research Database (Denmark)

    Fenger, M; Eriksen, P B; Andersen, O;

    1982-01-01

    Plasma concentrations of cyclic adenosine monophosphate and cyclic guanosine monophosphate were measured in 10 health adults before, during and after periods of theophylline administration. Cyclic adenosine monophosphate concentrations did not change significantly, but cyclic guanosine monophosph...

  19. Interleukin-6-type cytokines in neuroprotection and neuromodulation: Oncostatin M, but not leukemia inhibitory factor, requires neuronal Adenosine A1 receptor function

    NARCIS (Netherlands)

    Moidunny, S.; Dias, R.; Van Calker, D.; Boddeke, H.; Sebastiao, A.; Biber, K.

    2010-01-01

    Objective: Adenosine is a neuromodulator in the central nervous system exhibiting anticonvulsive, neuroprotective and sedating/sleep regulating properties. A pathophysiological importance of adenosine in various neuropsychiatric diseases (e.g. epilepsy, neurodegenerative disorders, apoplexia and moo

  20. Adenosine inhibits neutrophil vascular endothelial growth factor release and transendothelial migration via A2B receptor activation.

    LENUS (Irish Health Repository)

    Wakai, A

    2012-02-03

    The effects of adenosine on neutrophil (polymorphonuclear neutrophils; PMN)-directed changes in vascular permeability are poorly characterized. This study investigated whether adenosine modulates activated PMN vascular endothelial growth factor (vascular permeability factor; VEGF) release and transendothelial migration. PMN activated with tumour necrosis factor-alpha (TNF-alpha, 10 ng\\/mL) were incubated with adenosine and its receptor-specific analogues. Culture supernatants were assayed for VEGF. PMN transendothelial migration across human umbilical vein endothelial cell (HUVEC) monolayers was assessed in vitro. Adhesion molecule receptor expression was assessed flow cytometrically. Adenosine and some of its receptor-specific analogues dose-dependently inhibited activated PMN VEGF release. The rank order of potency was consistent with the affinity profile of human A2B receptors. The inhibitory effect of adenosine was reversed by 3,7-dimethyl-1-propargylxanthine, an A2 receptor antagonist. Adenosine (100 microM) or the A2B receptor agonist 5\\'-N-ethylcarboxamidoadenosine (NECA, 100 microM) significantly reduced PMN transendothelial migration. However, expression of activated PMN beta2 integrins and HUVEC ICAM-1 were not significantly altered by adenosine or NECA. Adenosine attenuates human PMN VEGF release and transendothelial migration via the A2B receptor. This provides a novel target for the modulation of PMN-directed vascular hyperpermeability in conditions such as the capillary leak syndrome.

  1. Chronic hypoxia increases arterial blood pressure and reduces adenosine and ATP induced vasodilatation in skeletal muscle in healthy humans

    DEFF Research Database (Denmark)

    Calbet, J A L; Boushel, Robert Christopher; Robach, P;

    2014-01-01

    AIMS: To determine the role played by adenosine, ATP and chemoreflex activation on the regulation of vascular conductance in chronic hypoxia. METHODS: The vascular conductance response to low and high doses of adenosine and ATP was assessed in ten healthy men. Vasodilators were infused into the f...

  2. Separation of effects of adenosine on energy metabolism from those on cyclic AMP in rat thymic lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Nordeen, S.K.; Young, D.A.

    1977-08-10

    In rat thymic lymphocytes incubated for 2 h without exogenous energy-providing substrate, adenosine may be substituted for glucose as a means of maximally restoring energy metabolism and those cellular functions whose rates are sensitive to small changes in the energy balance, such as protein synthesis and uridine utilization for RNA synthesis. Since effects of adenosine in thymocytes and other cells have frequently been attributed to changes in cyclic AMP, this report investigates its possible involvement in these glucose-like restorative actions of adenosine. Although the same range of doses of adenosine effective at raising cyclic AMP also elicit roughly parallel stimulations of protein synthesis and uridine utilization, further results dissociate the restorative actions from those on cyclic AMP. (a) Other purine nucleosides mimic the glucose-like actions of adenosine without increasing cyclic AMP; (b) conversely, prostaglandin E/sub 1/ mimics the cyclic AMP response without restoring energy metabolism or energy-dependent functions; and (c) potentiation of the cyclic AMP response, either by inhibiting phosphodiesterase or adenosine deaminase, does not enhance the restorative response to a range of doses of adenosine. Finally, cyclic AMP-mediated glycogenolysis cannot account for the glucose-like effects since addition of adenosine increases, not decreases, levels of glycogen.

  3. Determination of the onset of beta-methyl-digoxin action by potentiation of the adenosine response in guinea pigs.

    Directory of Open Access Journals (Sweden)

    Fukuda,Tamotsu

    1985-06-01

    Full Text Available The onset of beta-methyl-digoxin action was investigated by the potentiation of the adenosine response in guinea pigs and rats, and compared with that of digoxin and dipyridamole. A number of i.v. infusions of adenosine were given to determine the mean control adenosine response and its 95% confidence limits. After oral administration of the drugs, successive infusions of adenosine were continued until a drug-induced potentiation of the adenosine response was observed. The time of appearance of the potentiated adenosine response was marked as the onset of action of the drugs. The onset of action in guinea pigs was 9 to 12 min for 0.2 to 0.4 mg/kg of beta-methyl-digoxin, 90 to 100 min for 0.2 mg/kg of digoxin and 25 min for 5 mg/kg of dipyridamole. The maximal potentiation was 48.8 to 53.8% at 18 to 21 min for beta-methyl-digoxin, 74.5% at 130 min for digoxin and 74.8% at 80 min for dipyridamole. Adenosine infused i.v. into rats produced heart block, as in guinea pigs. However, in rats, the adenosine response was not potentiated by beta-methyl-digoxin and digoxin. Dipyridamole at a dose as high as 200 mg/kg produced 25.8% potentiation at 36 min after oral administration to rats.

  4. Comparison of adenosine and treadmill exercise thallium-201 stress tests for the detection of coronary artery disease.

    Science.gov (United States)

    Abe, S; Takeishi, Y; Chiba, J; Ikeda, K; Tomoike, H

    1993-12-01

    To determine the clinical usefulness of adenosine Tl-201 imaging for the evaluation of coronary artery disease, 22 patients with suspected coronary artery disease who underwent adenosine and exercise Tl-201 single photon emission computed tomography (SPECT) were studied. The peak levels of heart rate (83 vs 123 bpm, p pressure products (10220 vs 20410 bpm x mmHg, p < 0.001) were markedly smaller during adenosine infusion than during exercise. Segmental agreements between adenosine and exercise tests were 90% (218 of 242 segments) regarding the presence of perfusion defects and 89% (215 of 242 segments) regarding the presence of redistribution. Regional Tl-201 uptake (r = 0.85, p < 0.001) and the extent (r = 0.75, p < 0.001) and intensity (r = 0.83, p < 0.001) of Tl-201 defects during adenosine testing were closely correlated with those of exercise testing. Adenosine and exercise tests showed similar sensitivities for the identification of individual coronary stenosis (85% vs 78%). However, in patients who were unable to perform adequate exercise (maximal heart rate < 120 bpm), the sensitivity of adenosine imaging tended to be higher than that of exercise imaging (92% vs 69%, p = 0.07). Adenosine Tl-201 imaging is an alternative to the exercise test for assessing the severity and loci of coronary artery disease, especially in patients who are unable to perform adequate physical exercise. PMID:8283603

  5. Caffeine intake inverts the effect of adenosine on myocardial perfusion during stress as measured by T1 mapping

    NARCIS (Netherlands)

    Kuijpers, Dirkjan; Prakken, Niek H.; Vliegenthart, Rozemarijn; van Dijkman, Paul R. M.; van der Harst, Pim; Oudkerk, Matthijs

    2016-01-01

    Caffeine intake before adenosine stress myocardial perfusion imaging may cause false negative findings. We hypothesized that the antagonistic effect of caffeine can be measured by T1 relaxation times in rest and adenosine stress cardiac magnetic resonance imaging (CMR), as T1 mapping techniques are

  6. NTS adenosine A2a receptors inhibit the cardiopulmonary chemoreflex control of regional sympathetic outputs via a GABAergic mechanism.

    Science.gov (United States)

    Minic, Zeljka; O'Leary, Donal S; Scislo, Tadeusz J

    2015-07-01

    Adenosine is a powerful central neuromodulator acting via opposing A1 (inhibitor) and A2a (activator) receptors. However, in the nucleus of the solitary tract (NTS), both adenosine receptor subtypes attenuate cardiopulmonary chemoreflex (CCR) sympathoinhibition of renal, adrenal, and lumbar sympathetic nerve activity and attenuate reflex decreases in arterial pressure and heart rate. Adenosine A1 receptors inhibit glutamatergic transmission in the CCR pathway, whereas adenosine A2a receptors most likely facilitate release of an unknown inhibitory neurotransmitter, which, in turn, inhibits the CCR. We hypothesized that adenosine A2a receptors inhibit the CCR via facilitation of GABA release in the NTS. In urethane-chloralose-anesthetized rats (n = 51), we compared regional sympathetic responses evoked by stimulation of the CCR with right atrial injections of the 5-HT3 receptor agonist phenylbiguanide (1-8 μg/kg) before and after selective stimulation of NTS adenosine A2a receptors [microinjections into the NTS of CGS-21680 (20 pmol/50 nl)] preceded by blockade of GABAA or GABAB receptors in the NTS [bicuculline (10 pmol/100 nl) or SCH-50911 (1 nmol/100 nl)]. Blockade of GABAA receptors virtually abolished adenosine A2a receptor-mediated inhibition of the CCR. GABAB receptors had much weaker but significant effects. These effects were similar for the different sympathetic outputs. We conclude that stimulation of NTS adenosine A2a receptors inhibits CCR-evoked hemodynamic and regional sympathetic reflex responses via a GABA-ergic mechanism. PMID:25910812

  7. NTS adenosine A2a receptors inhibit the cardiopulmonary chemoreflex control of regional sympathetic outputs via a GABAergic mechanism.

    Science.gov (United States)

    Minic, Zeljka; O'Leary, Donal S; Scislo, Tadeusz J

    2015-07-01

    Adenosine is a powerful central neuromodulator acting via opposing A1 (inhibitor) and A2a (activator) receptors. However, in the nucleus of the solitary tract (NTS), both adenosine receptor subtypes attenuate cardiopulmonary chemoreflex (CCR) sympathoinhibition of renal, adrenal, and lumbar sympathetic nerve activity and attenuate reflex decreases in arterial pressure and heart rate. Adenosine A1 receptors inhibit glutamatergic transmission in the CCR pathway, whereas adenosine A2a receptors most likely facilitate release of an unknown inhibitory neurotransmitter, which, in turn, inhibits the CCR. We hypothesized that adenosine A2a receptors inhibit the CCR via facilitation of GABA release in the NTS. In urethane-chloralose-anesthetized rats (n = 51), we compared regional sympathetic responses evoked by stimulation of the CCR with right atrial injections of the 5-HT3 receptor agonist phenylbiguanide (1-8 μg/kg) before and after selective stimulation of NTS adenosine A2a receptors [microinjections into the NTS of CGS-21680 (20 pmol/50 nl)] preceded by blockade of GABAA or GABAB receptors in the NTS [bicuculline (10 pmol/100 nl) or SCH-50911 (1 nmol/100 nl)]. Blockade of GABAA receptors virtually abolished adenosine A2a receptor-mediated inhibition of the CCR. GABAB receptors had much weaker but significant effects. These effects were similar for the different sympathetic outputs. We conclude that stimulation of NTS adenosine A2a receptors inhibits CCR-evoked hemodynamic and regional sympathetic reflex responses via a GABA-ergic mechanism.

  8. Isoform-specific regulation of the Na+-K+ pump by adenosine in guinea pig ventricular myocytes

    Institute of Scientific and Technical Information of China (English)

    Zhe ZHANG; Hui-cai GUO; Li-nan ZHANG; Yong-li WANG

    2009-01-01

    Aim: The present study investigated the effect of adenosine on Na+-K+ pumps in acutely isolated guinea pig (C, avia sp.) ven-tricular myocytes.Methods: The whole-cell, patch-damp technique was used to record the Na+-K+ pump current (Ip) in acutely isolated guinea pig ventricular myocytes.Results: Adenosine inhibited the high DHO-affinity pump current (Ih) in a concentration-dependent manner, which was blocked by the selective adenosine A1 receptor antagonist DPCPX and the general protein kinase C (PKC) antagonists stau-rosporine, GF 109203X or the specific δ isoform antagonist rottlerin. In addition, the inhibitory action of adenosine was mimicked by a selective A1 receptor agonist CCPA and a specific activator peptide of PKC-δ, PP114. In contrast, the selec-tive A2A receptor agonist CGS21680 and A3 receptor agonist Cl-IB-MECA did not affect lb. Application of the selective A2A receptor antagonist SCH58261 and A3 receptor antagonist MRS1191 also failed to block the effect of adenosine. Further-more, H89, a selective protein kinase A (PKA) antagonist, did not exert any effect on adenosine-induced Ih inhibition.Conclusion: The present study provides the electrophysiological evidence that adenosine can induce significant inhibition of Ih via adenosine A1 receptors and the PKC-δ isoform.

  9. Wound Healing Is Accelerated by Agonists of Adenosine A2 (Gα s-linked) Receptors

    OpenAIRE

    Montesinos, M. Carmen; Gadangi, Pratap; Longaker, Michael; Sung, Joanne; Levine, Jamie; Nilsen, Diana; Reibman, Joan; Min LI; Jiang, Chuan-Kui; Hirschhorn, Rochelle; Recht, Phoebe A.; Ostad, Edward; Levin, Richard I.; Cronstein, Bruce N.

    1997-01-01

    The complete healing of wounds is the final step in a highly regulated response to injury. Although many of the molecular mediators and cellular events of healing are known, their manipulation for the enhancement and acceleration of wound closure has not proven practical as yet. We and others have established that adenosine is a potent regulator of the inflammatory response, which is a component of wound healing. We now report that ligation of the Gαs-linked adenosine receptors on the cells o...

  10. Investigation of the Interaction between Adenosine and Human Serum Albumin by Fluorescent Spectroscopy and Molecular Modeling

    Institute of Scientific and Technical Information of China (English)

    CUI Feng-Ling; WANG Jun-Li; LI Fang; FAN Jing; QU Gui-Rong; YAO Xiao-Jun; LEI Bei-Lei

    2008-01-01

    The binding interaction of adenosine with human serum albumin (HSA) was investigated under simulative physiological conditions by fluorescence spectroscopy in combination with a molecular modeling method. A strong fluorescence quenching reaction of adenosine to HSA was observed and the quenching mechanism was suggested as static quenching according to the Stern-Volmer equation. The binding constants (K) at different temperatures as well as thermodynamic parameters, enthalpy change (ΔH) and entropy change (ΔS), were calculated according to relevant fluorescent data and Vant'Hoff equation. The hydrophobic interaction was a predominant intermolecular force in order to stabilize the complex, which was in agreement with the results of molecular modeling study.

  11. Adenosine as a signaling molecule in the retina: biochemical and developmental aspects

    Directory of Open Access Journals (Sweden)

    ROBERTO PAES-DE-CARVALHO

    2002-09-01

    Full Text Available The nucleoside adenosine plays an important role as a neurotransmitter or neuromodulator in the central nervous system, including the retina. In the present paper we review compelling evidence showing that adenosine is a signaling molecule in the developing retina. In the chick retina, adenosine transporters are present since early stages of development before the appearance of adenosine A1 receptors modulating dopamine-dependent adenylate cyclase activity or A2 receptors that directly activate the enzyme. Experiments using retinal cell cultures revealed that adenosine is taken up by specific cell populations that when stimulated by depolarization or neurotransmitters such as dopamine or glutamate, release the nucleoside through calcium-dependent transporter-mediated mechanisms. The presence of adenosine in the extracellular medium and the long-term activation of adenosine receptors is able to regulate the survival of retinal neurons and blocks glutamate excitoxicity. Thus, adenosine besides working as a neurotransmitter or neuromodulator in the mature retina, is considered as an important signaling molecule during retinal development having important functions such as regulation of neuronal survival and differentiation.O nucleosídeo adenosina apresenta um importante papel como neurotransmissor ou neuromodulador no sistema nervoso central, inclusive na retina. Neste artigo apresentamos uma revisão das evidências que mostram que a adenosina é uma molécula sinalizadora na retina em desenvolvimento. Na retina de pinto, transportadores de adenosina estão presentes desde estágios precoces do desenvolvimento, antes do aparecimento dos receptores A1 que modulam a atividade adenilato ciclase dependente de dopamina ou dos receptores A2 que ativam diretamente a enzima. Experimentos usando culturas de células de retina revelaram que a adenosina é captada por populações celulares específicas que, quando estimuladas por despolarização ou por

  12. Adenosine modulates hypoxia-induced responses in rat PC12 cells via the A2A receptor.

    Science.gov (United States)

    Kobayashi, S; Conforti, L; Pun, R Y; Millhorn, D E

    1998-04-01

    1. The present study was undertaken to determine the role of adenosine in mediating the cellular responses to hypoxia in rat phaeochromocytoma (PC12) cells, an oxygen-sensitive clonal cell line. 2. Reverse transcriptase polymerase chain reaction studies revealed that PC12 cells express adenosine deaminase (the first catalysing enzyme of adenosine degradation) and the A2A and A2B adenosine receptors, but not the A1 or A3 adenosine receptors. 3. Whole-cell current- and voltage-clamp experiments showed that adenosine attenuated the hypoxia-induced membrane depolarization. The hypoxia-induced suppression of the voltage-sensitive potassium current (IK(V)) was markedly reduced by adenosine. Furthermore, extracellularly applied adenosine increased the peak amplitudes of IK(V) in a concentration-dependent manner. This increase was blocked by pretreatment not only with a non-specific adenosine receptor antagonist, 8-phenyltheophylline (8-PT), but also with a selective A2A receptor antagonist, ZM241385. 4. Ca2+ imaging studies using fura-2 acetoxymethyl ester (fura-2 AM) revealed that the increase in intracellular free Ca2+ during hypoxic exposure was attenuated significantly by adenosine. Voltage-clamp studies showed that adenosine inhibited the voltage-dependent Ca2+ currents (ICa) in a concentration-dependent fashion. This inhibition was also abolished by both 8-PT and ZM241385. 5. The modulation of both IK(V) and ICa by adenosine was prevented by intracellular application of an inhibitor of protein kinase A (PKA), PKA inhibitor fragment (6-22) amide. In addition, the effect of adenosine on either IK(V) or ICa was absent in PKA-deficient PC12 cells. 6. These results indicate that the modulatory effects of adenosine on the hypoxia-induced membrane responses of PC12 cells are likely to be mediated via activation of the A2A receptor, and that the PKA pathway is required for these modulatory actions. We propose that this modulation serves to regulate membrane excitability in

  13. Systemic administration of the adenosine A2A agonist CGS 21680 induces sedation at doses that suppress lever pressing and food intake

    OpenAIRE

    Mingote, Susana; Pereira, Mariana; Farrar, Andrew M.; McLaughlin, Peter J.; Salamone, John D.

    2008-01-01

    Adenosine A2A receptors are involved in the regulation of several behavioral functions. Adenosine A2A antagonists exert antiparkinsonian effects in animal models, and adenosine A2A agonists suppress locomotion and impair various aspects of motor control. The present experiments were conducted to study the effects of low doses of the adenosine A2A agonist CGS 21680 on lever pressing, specific parameters of food intake, and sedation. In the first experiment, the effects of CGS 21680 on fixed ra...

  14. Development of a human-specific B. thetaiotaomicron IMS/ATP assay for measuring viable human contamination in surface waters in Baja California, Mexico

    Science.gov (United States)

    Immunomagnetic separation/adenosine triphosphate (IMS/ATP) assays utilize paramagnetic beads and target-specific antibodies to isolate target organisms. Following isolation, adenosine tri-phosphate (ATP) is extracted from the target population and quantified. An inversely-couple...

  15. Muscle 3243A -> G mutation load and capacity of the mitochondrial energy-generating system

    NARCIS (Netherlands)

    Janssen, Antoon J. M.; Schuelke, Markus; Smeitink, Jan A. M.; Trijbels, Frans J. M.; Sengers, Rob C. A.; Lucke, Barbara; Wintjes, Liesbeth T. M.; Morava, Eva; van Engelen, Baziel G. M.; Struts, Bart W.; Hol, Frans A.; Siers, Marloes H.; ter Laak, Henk; van der Knaap, Marjo S.; van Spronsen, Francjan J.; Rodenburg, Richard J. T.; van den Heuvel, Lambert P.

    2008-01-01

    Objective: The mitochondrial energy-generating system (MEGS) encompasses the mitochondrial enzymatic reactions from oxidation of pyruvate to the export of adenosine triphosphate. It is investigated in intact muscle mitochondria by measuring the pyruvate oxidation and adenosine triphosphate productio

  16. Muscle 3243A-->G mutation load and capacity of the mitochondrial energy-generating system.

    NARCIS (Netherlands)

    Janssen, A.J.; Schuelke, M.; Smeitink, J.A.M.; Trijbels, F.J.; Sengers, R.C.; Lucke, B.; Wintjes, L.T.; Morava, E.; Engelen, B.G.M. van; Smits, B.W.; Hol, F.A.; Siers, M.H.; Laak, H. ter; Knaap, M.S. van der; Spronsen, F.J. van; Rodenburg, R.J.; Heuvel, L.P.v.d.

    2008-01-01

    OBJECTIVE: The mitochondrial energy-generating system (MEGS) encompasses the mitochondrial enzymatic reactions from oxidation of pyruvate to the export of adenosine triphosphate. It is investigated in intact muscle mitochondria by measuring the pyruvate oxidation and adenosine triphosphate productio

  17. The Safety of an Adenosine A(1)-Receptor Antagonist, Rolofylline, in Patients with Acute Heart Failure and Renal Impairment Findings from PROTECT

    NARCIS (Netherlands)

    Teerlink, John R.; Iragui, Vicente J.; Mohr, Jay P.; Carson, Peter E.; Hauptman, Paul J.; Lovett, David H.; Miller, Alan B.; Pina, Ileana L.; Thomson, Scott; Varosy, Paul D.; Zile, Michael R.; Cleland, John G. F.; Givertz, Michael M.; Metra, Marco; Ponikowski, Piotr; Voors, Adriaan A.; Davison, Beth A.; Cotter, Gad; Wolko, Denise; DeLucca, Paul; Salerno, Christina M.; Mansoor, George A.; Dittrich, Howard; O'Connor, Christopher M.; Massi, Barry M.

    2012-01-01

    Background: Adenosine exerts actions in multiple organ systems, and adenosine receptors are a therapeutic target in many development programmes. Objective: The aim of this analysis was to evaluate the safety of rolofylline, an adenosine A(1)-receptor antagonist, in patients with acute heart failure.

  18. Adenosine A(1) Receptors in the Central Nervous System : Their Functions in Health and Disease, and Possible Elucidation by PET Imaging

    NARCIS (Netherlands)

    Paul, S.; Elsinga, P. H.; Ishiwata, K.; Dierckx, R. A. J. O.; van Waarde, A.

    2011-01-01

    Adenosine is a neuromodulator with several functions in the central nervous system (CNS), such as inhibition of neuronal activity in many signaling pathways. Most of the sedating, anxiolytic, seizure-inhibiting and protective actions of adenosine are mediated by adenosine A(1) receptors (A(1)R) on t

  19. Recent developments in A2B adenosine receptor ligands.

    Science.gov (United States)

    Kalla, Rao V; Zablocki, Jeff; Tabrizi, Mojgan Aghazadeh; Baraldi, Pier Giovanni

    2009-01-01

    A selective, high-affinity A(2B) adenosine receptor (AR) antagonist will be useful as a pharmacological tool to help determine the role of the A(2B)AR in inflammatory diseases and angiogenic diseases. Based on early A(2B)AR-selective ligands with nonoptimal pharmaceutical properties, such as 15 (MRS 1754: K(i)(hA(2B)) = 2 nM; K(i)(hA(1)) = 403 nM; K(i)(hA(2A)) = 503 NM, and K(i)(hA(3)) = 570 nM), several groups have discovered second-generation A(2B)AR ligands that are suitable for development. Scientists at CV Therapeutics have discovered the selective, high-affinity A(2B)AR antagonist 22, a 8-(4-pyrazolyl)-xanthine derivative, (CVT-6883, K(i)(hA(2B)) = 22 nM; K(i)(hA(1)) = 1,940 nM; K(i)(hA(2A)) = 3,280; and K(i)(hA(3)) = 1,070 nM). Compound 22 has demonstrated favorable pharmacokinetic (PK) properties (T(1/2) = 4 h and F > 35% rat), and it is a functional antagonist at the A(2B)AR(K (B) = 6 nM). In a mouse model of asthma, compound 22 demonstrated a dose-dependent efficacy supporting the role of the A(2B)AR in asthma. In two Phase I clinical trails, 22 (CVT-6883) was found to be safe, well tolerated, and suitable for once-daily dosing. Baraldi et al. have independently discovered a selective, high-affinity A(2B)AR antagonist, 30 (MRE2029F20), 8-(5-pyrazolyl)-xanthine (K(i)(hA(2B)) = 5.5 nM; K(i)(hA(1)) = 200 nM; K(i)(hA(2A), A(3)) > 1,000, that has been selected for development in conjunction with King Pharmaceuticals. Compound 30 has been demonstrated to be a functional antagonist of the A(2B)AR, and it has been radiolabeled for use in pharmacological studies. A third compound, 58 (LAS-38096), is a 2-aminopyrimidine derivative (discovered by the Almirall group) that has high A(2B)AR affinity and selectivity (K(i)(hA(2B)) = 17 nM; K(i)(hA(1)) > 1,000 nM; K(i)(hA(2A)) > 2,500; and K(i)(hA(3)) > 1,000 nM), and 58 has been moved into preclinical safety testing. A fourth selective, high-affinity A(2B)AR antagonist, 54 (OSIP339391 K(i))(hA(2B)) = 0.5 nM; K(i))(hA(1

  20. REPRODUCTIVE CONDITION, GLOMERULAR ADENOSINE DIPHOSPHATASE ACTIVITY, AND PLATELET-AGGREGATION IN THE RAT - EFFECT OF ENDOTOXIN

    NARCIS (Netherlands)

    VISSCHER, CA; FAAS, MM; BAKKER, WW; SCHUILING, GA

    1993-01-01

    In experiment A, the activity of the glomerular antithrombotic enzyme adenosine diphosphatase (ADPase) and the sensitivity of this enzyme for endotoxin (1.0 mug/kg BW) in various reproductive conditions of female rats were studied through use of enzyme histochemical methods. In experiment B, the eff

  1. High fetal plasma adenosine concentration: a role for the fetus in preeclampsia?

    LENUS (Irish Health Repository)

    Espinoza, Jimmy

    2012-02-01

    OBJECTIVE: Clinical observations suggest a role for the fetus in the maternal manifestations of preeclampsia, but the possible signaling mechanisms remain unclear. This study compares the fetal plasma concentrations of adenosine from normal pregnancies with those from preeclampsia. STUDY DESIGN: This secondary data analysis included normal pregnancies (n = 27) and patients with preeclampsia (n = 39). Patients with preeclampsia were subclassified into patients with (n = 25) and without (n = 14) abnormal uterine artery Doppler velocimetry (UADV). RESULTS: Fetal plasma concentrations of adenosine were significantly higher in patients with preeclampsia (1.35 +\\/- 0.09 mumol\\/L) than in normal pregnancies (0.52 +\\/- 0.06 mumol\\/L; P < .0001). Fetal plasma concentrations of adenosine in patients with preeclampsia with abnormal UADV (1.78 +\\/- 0.15 mumol\\/L), but not with normal UADV (0.58 +\\/- 0.14 mumol\\/L), were significantly higher than in normal pregnancies (P < .0001). CONCLUSION: Patients with preeclampsia with sonographic evidence of chronic uteroplacental ischemia have high fetal plasma concentrations of adenosine.

  2. Adenosine A2A Receptors Modulate Acute Injury and Neuroinflammation in Brain Ischemia

    Directory of Open Access Journals (Sweden)

    Felicita Pedata

    2014-01-01

    Full Text Available The extracellular concentration of adenosine in the brain increases dramatically during ischemia. Adenosine A2A receptor is expressed in neurons and glial cells and in inflammatory cells (lymphocytes and granulocytes. Recently, adenosine A2A receptor emerged as a potential therapeutic attractive target in ischemia. Ischemia is a multifactorial pathology characterized by different events evolving in the time. After ischemia the early massive increase of extracellular glutamate is followed by activation of resident immune cells, that is, microglia, and production or activation of inflammation mediators. Proinflammatory cytokines, which upregulate cell adhesion molecules, exert an important role in promoting recruitment of leukocytes that in turn promote expansion of the inflammatory response in ischemic tissue. Protracted neuroinflammation is now recognized as the predominant mechanism of secondary brain injury progression. A2A receptors present on central cells and on blood cells account for important effects depending on the time-related evolution of the pathological condition. Evidence suggests that A2A receptor antagonists provide early protection via centrally mediated control of excessive excitotoxicity, while A2A receptor agonists provide protracted protection by controlling massive blood cell infiltration in the hours and days after ischemia. Focus on inflammatory responses provides for adenosine A2A receptor agonists a wide therapeutic time-window of hours and even days after stroke.

  3. Outcome of hematopoietic stem cell transplantation for adenosine deaminase-deficient severe combined immunodeficiency

    NARCIS (Netherlands)

    Hassan, Amel; Booth, Claire; Brightwell, Alex; Allwood, Zoe; Veys, Paul; Rao, Kanchan; Hoenig, Manfred; Friedrich, Wilhelm; Gennery, Andrew; Slatter, Mary; Bredius, Robbert; Finocchi, Andrea; Cancrini, Caterina; Aiuti, Alessandro; Porta, Fulvio; Lanfranchi, Arnalda; Ridella, Michela; Steward, Colin; Filipovich, Alexandra; Marsh, Rebecca; Bordon, Victoria; Al-Muhsen, Saleh; Al-Mousa, Hamoud; Alsum, Zobaida; Al-Dhekri, Hasan; Al Ghonaium, Abdulaziz; Speckmann, Carsten; Fischer, Alain; Mahlaoui, Nizar; Nichols, Kim E.; Grunebaum, Eyal; Al Zahrani, Daifulah; Roifman, Chaim M.; Boelens, Jaap; Davies, E. Graham; Cavazzana-Calvo, Marina; Notarangelo, Luigi; Gaspar, H. Bobby

    2012-01-01

    Deficiency of the purine salvage enzyme adenosine deaminase leads to SCID (ADA-SCID). Hematopoietic cell transplantation (HCT) can lead to a permanent cure of SCID; however, little data are available on outcome of HCT for ADA-SCID in particular. In this multicenter retrospective study, we analyzed o

  4. A2BR adenosine receptor modulates sweet taste in circumvallate taste buds.

    Directory of Open Access Journals (Sweden)

    Shinji Kataoka

    Full Text Available In response to taste stimulation, taste buds release ATP, which activates ionotropic ATP receptors (P2X2/P2X3 on taste nerves as well as metabotropic (P2Y purinergic receptors on taste bud cells. The action of the extracellular ATP is terminated by ectonucleotidases, ultimately generating adenosine, which itself can activate one or more G-protein coupled adenosine receptors: A1, A2A, A2B, and A3. Here we investigated the expression of adenosine receptors in mouse taste buds at both the nucleotide and protein expression levels. Of the adenosine receptors, only A2B receptor (A2BR is expressed specifically in taste epithelia. Further, A2BR is expressed abundantly only in a subset of taste bud cells of posterior (circumvallate, foliate, but not anterior (fungiform, palate taste fields in mice. Analysis of double-labeled tissue indicates that A2BR occurs on Type II taste bud cells that also express Gα14, which is present only in sweet-sensitive taste cells of the foliate and circumvallate papillae. Glossopharyngeal nerve recordings from A2BR knockout mice show significantly reduced responses to both sucrose and synthetic sweeteners, but normal responses to tastants representing other qualities. Thus, our study identified a novel regulator of sweet taste, the A2BR, which functions to potentiate sweet responses in posterior lingual taste fields.

  5. Pyrazolo Derivatives as Potent Adenosine Receptor Antagonists: An Overview on the Structure-Activity Relationships

    Directory of Open Access Journals (Sweden)

    Siew Lee Cheong

    2011-01-01

    Full Text Available In the past few decades, medicinal chemistry research towards potent and selective antagonists of human adenosine receptors (namely, A1, A2A, A2B, and A3 has been evolving rapidly. These antagonists are deemed therapeutically beneficial in several pathological conditions including neurological and renal disorders, cancer, inflammation, and glaucoma. Up to this point, many classes of compounds have been successfully synthesized and identified as potent human adenosine receptor antagonists. In this paper, an overview of the structure-activity relationship (SAR profiles of promising nonxanthine pyrazolo derivatives is reported and discussed. We have emphasized the SAR for some representative structures such as pyrazolo-[4,3-e]-1,2,4-triazolo-[1,5-c]pyrimidines; pyrazolo-[3,4-c] or -[4,3-c]quinolines; pyrazolo-[4,3-d]pyrimidinones; pyrazolo-[3,4-d]pyrimidines and pyrazolo-[1,5-a]pyridines. This overview not only clarifies the structural requirements deemed essential for affinity towards individual adenosine receptor subtypes, but it also sheds light on the rational design and optimization of existing structural templates to allow us to conceive new, more potent adenosine receptor antagonists.

  6. Passive targeting of ischemic-reperfused myocardium with adenosine-loaded silica nanoparticles

    Directory of Open Access Journals (Sweden)

    Galagudza M

    2012-04-01

    Full Text Available Michael Galagudza1, Dmitry Korolev1, Viktor Postnov2, Elena Naumisheva2, Yulia Grigorova3, Ivan Uskov1, Eugene Shlyakhto11Institute of Experimental Medicine, VA Almazov Federal Heart, Blood and Endocrinology Center, 2Chemical Faculty, St Petersburg State University, 3Department of Pathophysiology, IP Pavlov State Medical University, St Petersburg, Russian FederationAbstract: Pharmacological agents suggested for infarct size limitation have serious side effects when used at cardioprotective doses which hinders their translation into clinical practice. The solution to the problem might be direct delivery of cardioprotective drugs into ischemic-reperfused myocardium. In this study, we explored the potential of silica nanoparticles for passive delivery of adenosine, a prototype cardioprotective agent, into ischemic-reperfused heart tissue. In addition, the biodegradation of silica nanoparticles was studied both in vitro and in vivo. Immobilization of adenosine on the surface of silica nanoparticles resulted in enhancement of adenosine-mediated infarct size limitation in the rat model. Furthermore, the hypotensive effect of adenosine was attenuated after its adsorption on silica nanoparticles. We conclude that silica nanoparticles are biocompatible materials that might potentially be used as carriers for heart-targeted drug delivery.Keywords: silica nanoparticles, targeted drug delivery, myocardium, ischemia, reperfusion

  7. Therapeutic efficacy of the adenosine A1 receptor agonist N6-cyclopentyladenosine (CPA) against organophosphate intoxication

    NARCIS (Netherlands)

    Bueters, T.J.H.; Groen, B.; Danhof, M.; IJzerman, A.P.; Helden, H.P.M. van

    2002-01-01

    The objective of the present study was to investigate whether reduction of central acetylcholine (ACh) accumulation by adenosine receptor agonists could serve as a generic treatment against organophosphate (OP) poisoning. The OPs studied were tabun (O-ethyl-N-dimethylphosphoramidocyanidate), sarin (

  8. SIGNIFICANCE OF ADENOSINE DEAMINASE SERUM CONCENTRATIONS IN THE DIAGNOSIS OF EXTRA-PULMONARY TUBERCULOSIS

    Directory of Open Access Journals (Sweden)

    Stevanovic G,

    2011-06-01

    Full Text Available Extra pulmonary tuberculosis (EPTB is a growing problem worldwide. Due to the nature of the disease, the diversity of clinical pictures as well as its minor epidemiological importance, the diagnosis is difficult and often late.In addition to standard TB diagnostic techniques use of new biochemical (surrogate markers are increased. With this work we wanted to examine the usefulness of serum adenosine deaminase levels as a diagnostic parameter for EPTB.The work included 116 patients with fever of unknown origin in which tuberculosis or infectious mononucleosis was not proven and 51 person who had proven EPTB. Correlated adenosine deaminase levels between these two groups we obtained significantly higher values ​​in patients with EPTB. The calculated sensitivity was 0.56, specificity 0.89, positive predictive value 0.80 and negative predictive value 0.72. Certain reducing of the values observed during anti TB therapy. In previous studies the diagnostic importance of adenosine deaminase in the diagnosis of tuberculosis serosityes was demonstrated. The significance of serum levels in diagnosis is rarely evaluated during EPTB. Our findings are similar to the results of authors who have conducted such testing in the pediatric population.Increased concentrations of serum adenosine deaminase have shown the potential of usable screening test and can be used as an indicative EPTB parameter. To fully assess its diagnostic significance require future clinical research.

  9. Ischemic nucleotide breakdown increases during cardiac development due to drop in adenosine anabolism/catabolism ratio

    NARCIS (Netherlands)

    J.W. de Jong (Jan Willem); E. Keijzer (Elisabeth); T. Huizer (Tom); B. Schoutsen

    1990-01-01

    markdownabstractAbstract Our earlier work on reperfusion showed that adult rat hearts released almost twice as much purine nucleosides and oxypurines as newborn hearts did [Am J Physiol 254 (1988) H1091]. A change in the ratio anabolism/catabolism of adenosine could be responsible for this effect.

  10. Role of nitric oxide in adenosine-induced vasodilation in humans

    Science.gov (United States)

    Costa, F.; Biaggioni, I.; Robertson, D. (Principal Investigator)

    1998-01-01

    Vasodilation is one of the most prominent effects of adenosine and one of the first to be recognized, but its mechanism of action is not completely understood. In particular, there is conflicting information about the potential contribution of endothelial factors. The purpose of this study was to explore the role of nitric oxide in the vasodilatory effect of adenosine. Forearm blood flow responses to intrabrachial adenosine infusion (125 microg/min) were assessed with venous occlusion plethysmography during intrabrachial infusion of saline or the nitric oxide synthase inhibitor NG-monomethyl-L-arginine (L-NMMA) (12.5 mg/min). Intrabrachial infusions of acetylcholine (50 microg/min) and nitroprusside (3 microg/min) were used as a positive and negative control, respectively. These doses were chosen to produce comparable levels of vasodilation. In a separate study, a second saline infusion was administered instead of L-NMMA to rule out time-related effects. As expected, pretreatment with L-NMMA reduced acetylcholine-induced vasodilation; 50 microg/min acetylcholine increased forearm blood flow by 150+/-43% and 51+/-12% during saline and L-NMMA infusion, respectively (P<.01, n=6). In contrast, L-NMMA did not affect the increase in forearm blood flow produced by 3 microg/min nitroprusside (165+/-30% and 248+/-41% during saline and L-NMMA, respectively) or adenosine (173+/-48% and 270+/-75% during saline and L-NMMA, respectively). On the basis of our observations, we conclude that adenosine-induced vasodilation is not mediated by nitric oxide in the human forearm.

  11. Nucleus tractus solitarii A(2a) adenosine receptors inhibit cardiopulmonary chemoreflex control of sympathetic outputs.

    Science.gov (United States)

    Minic, Zeljka; O'Leary, Donal S; Scislo, Tadeusz J

    2014-02-01

    Previously we have shown that stimulation of inhibitory A1 adenosine receptors located in the nucleus tractus solitarii (NTS) attenuates cardiopulmonary chemoreflex (CCR) evoked inhibition of renal, adrenal and lumbar sympathetic nerve activity and reflex decreases in arterial pressure and heart rate. Activation of facilitatory A2a adenosine receptors, which dominate over A1 receptors in the NTS, contrastingly alters baseline activity of regional sympathetic outputs: it decreases renal, increases adrenal and does not change lumbar nerve activity. Considering that NTS A2a receptors may facilitate release of inhibitory transmitters we hypothesized that A2a receptors will act in concert with A1 receptors differentially inhibiting regional sympathetic CCR responses (adrenal>lumbar>renal). In urethane/chloralose anesthetized rats (n=38) we compared regional sympathetic responses evoked by stimulation of the CCR with right atrial injections of serotonin 5HT3 receptor agonist, phenylbiguanide, (1-8μg/kg) before and after selective stimulation, blockade or combined blockade and stimulation of NTS A2a adenosine receptors (microinjections into the NTS of CGS-21680 0.2-20pmol/50nl, ZM-241385 40pmol/100nl or ZM-241385+CGS-21680, respectively). We found that stimulation of A2a adenosine receptors uniformly inhibited the regional sympathetic and hemodynamic reflex responses and this effect was abolished by the selective blockade of NTS A2a receptors. This indicates that A2a receptor triggered inhibition of CCR responses and the contrasting shifts in baseline sympathetic activity are mediated via different mechanisms. These data implicate that stimulation of NTS A2a receptors triggers unknown inhibitory mechanism(s) which in turn inhibit transmission in the CCR pathway when adenosine is released into the NTS during severe hypotension. PMID:24216055

  12. Insights into the molecular mechanism of inhibition and drug resistance for HIV-1 RT with carbovir triphosphate.

    Science.gov (United States)

    Ray, Adrian S; Yang, Zhenjun; Shi, Junxing; Hobbs, Ann; Schinazi, Raymond F; Chu, Chung K; Anderson, Karen S

    2002-04-23

    Abacavir (1592U89, or Ziagen) is a powerful and selective inhibitor of HIV-1 viral replication that has been approved by the FDA for treatment of acquired immunodeficiency syndrome. Abacavir is metabolized to the active compound carbovir triphosphate (CBVTP). This compound is a guanosine analogue containing a 2',3'-unsaturation in its planar carbocyclic deoxyribose ring that acts on HIV-1 reverse transcriptase (RT(WT)) as a molecular target, resulting in chain termination of DNA synthesis. A single amino acid change from methionine 184 to valine in HIV-1 RT (RT(M184V)) has been observed clinically in response to abacavir treatment. The ability of the natural substrate, dGTP, or CBVTP to be utilized during DNA- and RNA-directed polymerization by RT(WT) and RT(M184V) was defined by pre-steady-state kinetic parameters. In the case of RT(WT), CBVTP was found to be a surprisingly poor substrate relative to dGTP. In both DNA- and RNA-directed polymerization, a decrease in the efficiency of CBVTP utilization with respect to dGTP was found with RT(M184V), suggesting that this mutation confers resistance at the level of CBVMP incorporation. The relatively low incorporation efficiency for RT(WT) was unanticipated considering earlier studies showing that the triphosphate form of a thymidine nucleoside analogue containing a planar 2',3'-unsaturated ribose ring, D4TTP, was incorporated with high efficiency relative to the natural substrate, dTTP. The difference may be related to the isosteric replacement of oxygen in the deoxyribose ring with carbon. This hypothesis was tested by synthesizing and evaluating D4GTP (the planar 2',3'-unsaturated deoxyribose guanosine analogue that is complementary to D4TTP). In contrast to CBVTP, D4GTP was found to be an excellent substrate for RT(WT) and no resistance was conferred by the M184V mutation, thus providing novel insight into structure-activity relationships for nucleoside-based inhibitors. In this work, we illustrate how an

  13. Leishmania infantum ecto-nucleoside triphosphate diphosphohydrolase-2 is an apyrase involved in macrophage infection and expressed in infected dogs.

    Directory of Open Access Journals (Sweden)

    Raphael De Souza Vasconcellos

    2014-11-01

    Full Text Available Visceral leishmaniasis is an important tropical disease, and Leishmania infantum chagasi (synonym of Leishmania infantum is the main pathogenic agent of visceral leishmaniasis in the New World. Recently, ecto-nucleoside triphosphate diphosphohydrolases (E-NTPDases were identified as enablers of infection and virulence factors in many pathogens. Two putative E-NTPDases (∼70 kDa and ∼45 kDa have been found in the L. infantum genome. Here, we studied the ∼45 kDa E-NTPDase from L. infantum chagasi to describe its natural occurrence, biochemical characteristics and influence on macrophage infection.We used live L. infantum chagasi to demonstrate its natural ecto-nucleotidase activity. We then isolated, cloned and expressed recombinant rLicNTPDase-2 in bacterial system. The recombinant rLicNTPDase-2 hydrolyzed a wide variety of triphosphate and diphosphate nucleotides (GTP> GDP  =  UDP> ADP> UTP  =  ATP in the presence of calcium or magnesium. In addition, rLicNTPDase-2 showed stable activity over a pH range of 6.0 to 9.0 and was partially inhibited by ARL67156 and suramin. Microscopic analyses revealed the presence of this protein on cell surfaces, vesicles, flagellae, flagellar pockets, kinetoplasts, mitochondria and nuclei. The blockade of E-NTPDases using antibodies and competition led to lower levels of parasite adhesion and infection of macrophages. Furthermore, immunohistochemistry showed the expression of E-NTPDases in amastigotes in the lymph nodes of naturally infected dogs from an area of endemic visceral leishmaniasis.In this work, we cloned, expressed and characterized the NTPDase-2 from L. infantum chagasi and demonstrated that it functions as a genuine enzyme from the E-NTPDase/CD39 family. We showed that E-NTPDases are present on the surface of promastigotes and in other intracellular locations. We showed, for the first time, the broad expression of LicNTPDases in naturally infected dogs. Additionally, the blockade of

  14. Electrochemical aptasensor for the detection of adenosine by using PdCu@MWCNTs-supported bienzymes as labels.

    Science.gov (United States)

    Wu, Dan; Ren, Xiang; Hu, Lihua; Fan, Dawei; Zheng, Yang; Wei, Qin

    2015-12-15

    A highly sensitive electrochemical adenosine aptasensor was fabricated by covalently immobilizing 3'-NH2-terminated capture probe (SSDNA1) and thionine (TH) on Au-GS modified glassy carbon electrode. 3'-SH-terminated adenosine aptamer (SSDNA2) was adsorbed onto palladium/copper alloyed supported on MWCNTs (PdCu@MWCNTs)-conjugated multiple bienzymes, glucose oxidase (GOx), and horseradish peroxidase (HRP) (SSDNA2/PdCu@MWCNTs/HRP/GOx). Then, it was immobilized onto the electrode surface through the hybridization between the adenosine aptamer and the capture probe. The signal was amplified based on the gradual electrocatalytic reduction of GOx-generated hydrogen peroxide by the multiple HRP through the mediating ability of the loaded multiple TH. However, the peak current of TH decreased in the presence of adenosine because the interaction between adenosine and its aptamer made SSDNA2/PdCu@MWCNTs/HRP/GOx release from the modified electrode. Various experimental parameters have been optimized for the detection of adenosine and tests for selectivity, reproducibility and stability have also been performed. Under the optimal condition, the proposed aptasensor displayed a wide linear range (10-400 nM) with the low detection limit (2.5 nM), which has been applied in human serum samples with satisfactory results. Thus, the combination of Au-GS as a sensor platform and PdCu@MWCNTs/HRP/GOx as labels can be a promising amplification strategy for highly sensitive adenosine detection. PMID:26164010

  15. Activation of adenosine receptors and inhibition of cyclooxygenases: two recent pharmacological approaches to modulation of radiation suppressed hematopoiesis

    International Nuclear Information System (INIS)

    Searching for drugs conforming to requirements for protection and/or treatment of radiation-induced damage belongs to the most important tasks of current radiobiology. In the Laboratory of Experimental Hematology, Institute of Biophysics, v.v.i., Academy of Sciences of the Czech Republic, Brno, Czech Republic, two original approaches for stimulation of radiation-suppressed hematopoiesis have been tested in recent years, namely activation of adenosine receptors and inhibition of cyclooxygenases. Non-selective activation of adenosine receptors, induced by combined administration of dipyridamole, a drug preventing adenosine uptake and supporting thus its extracellular receptor-mediated action, and adenosine monophosphate, an adenosine prodrug, has been found to stimulate hematopoiesis when the drugs were given either pre- or post-irradiation. When synthetic adenosine receptor agonists selective for individual adenosine receptor subtypes were tested, stimulatory effects in myelosuppressed mice have been found after administration of IB-MECA, a selective adenosine A3 receptor agonist. Non-selective cyclooxygenase inhibitors, inhibiting both cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2), indomethacin, diclofenac, or flurbiprofen, have been observed to act positively on radiation-perturbed hematopoiesis in sublethally irradiated mice. However, their undesirable gastrointestinal side effects have been found to negatively influence survival of lethally irradiated animals. Recently tested selective COX-2 inhibitor meloxicam, preserving protective action of COX-1-synthesized prostaglandins in the gastrointestinal tissues, has been observed to retain the hematopoiesis-stimulating effects of non-selective cyclooxygenase inhibitors and to improve the survival of animals exposed to lethal radiation doses. These findings bear evidence for the possibility to use selective adenosine A3 receptor agonists and selective COX-2 inhibitors in human practice for treatment of

  16. Light-driven artificial enzymes for selective oxidation of guanosine triphosphate using water-soluble POSS network polymers.

    Science.gov (United States)

    Jeon, Jong-Hwan; Tanaka, Kazuo; Chujo, Yoshiki

    2014-09-01

    The light-driven artificial enzymes were constructed to realize unnatural reactions concerning bio-significant molecules. In this manuscript, the guanosine triphosphate (GTP)-selective oxidation is reported using the network polymers composed of polyhedral oligomeric silsesquioxane (POSS). We synthesized the water-soluble POSS network polymer containing the naphthyridine ligands to capture GTP inside the networks and the ruthenium complexes to oxidize the captured GTP under light irradiation. Initially, the binding affinities of the guanosine nucleosides to the naphthyridine ligand inside the POSS network polymer were evaluated from the emission quenching experiments. Accordingly, it was observed that the naphthyridine ligand can form the stable complex only with GTP (K(a) = 5.5 × 10(6) M(-1)). These results indicate that only GTP can be captured by the network polymer. Next, the photo-catalytic activity of the ruthenium complex-modified POSS network polymer was investigated. Finally, it was revealed that the network polymer can decompose GTP efficiently under light irradiation. This is the first example, to the best of our knowledge, to offer not only the GTP-selective host polymers but also the light-driven artificial enzyme for GTP oxidation. PMID:25026217

  17. Binding of Mn-deoxyribonucleoside Triphosphates to the Active Site of the DNA Polymerase of Bacteriophage T7

    Energy Technology Data Exchange (ETDEWEB)

    B Akabayov; C Richardson

    2011-12-31

    Divalent metal ions are crucial as cofactors for a variety of intracellular enzymatic activities. Mg{sup 2+}, as an example, mediates binding of deoxyribonucleoside 5'-triphosphates followed by their hydrolysis in the active site of DNA polymerase. It is difficult to study the binding of Mg{sup 2+} to an active site because Mg{sup 2+} is spectroscopically silent and Mg{sup 2+} binds with low affinity to the active site of an enzyme. Therefore, we substituted Mg{sup 2+} with Mn{sup 2+}:Mn{sup 2+} that is not only visible spectroscopically but also provides full activity of the DNA polymerase of bacteriophage T7. In order to demonstrate that the majority of Mn{sup 2+} is bound to the enzyme, we have applied site-directed titration analysis of T7 DNA polymerase using X-ray near edge spectroscopy. Here we show how X-ray near edge spectroscopy can be used to distinguish between signal originating from Mn{sup 2+} that is free in solution and Mn{sup 2+} bound to the active site of T7 DNA polymerase. This method can be applied to other enzymes that use divalent metal ions as a cofactor.

  18. Leishmania (Viannia) braziliensis nucleoside triphosphate diphosphohydrolase (NTPDase 1): localization and in vitro inhibition of promastigotes growth by polyclonal antibodies.

    Science.gov (United States)

    Porcino, Gabriane Nascimento; Carvalho-Campos, Cristiane; Maia, Ana Carolina Ribeiro Gomes; Detoni, Michelle Lima; Faria-Pinto, Priscila; Coimbra, Elaine Soares; Marques, Marcos José; Juliano, Maria Aparecida; Juliano, Luiz; Diniz, Vanessa Álvaro; Corte-Real, Suzana; Vasconcelos, Eveline Gomes

    2012-10-01

    Nucleoside triphosphate diphosphohydrolase (NTPDase) activity was recently characterized in Leishmania (Viannia) braziliensis promastigotes (Lb), and an antigenic conserved domain (r82-121) from the specific NTPDase 1 isoform was identified. In this work, mouse polyclonal antibodies produced against two synthetic peptides derived from this domain (LbB1LJ, r82-103; LbB2LJ, r102-121) were used. The anti-LbB1LJ or anti-LbB2LJ antibodies were immobilized on protein A-sepharose and immunoprecipitated the NTPDase 1 of 48 kDa and depleted approximately 40% of the phosphohydrolytic activity from detergent-homogenized Lb preparation. Ultrastructural immunocytochemical microscopy identified the NTPDase 1 on the parasite surface and in its subcellular cytoplasmic vesicles, mitochondria, kinetoplast and nucleus. The ATPase and ADPase activities of detergent-homogenized Lb preparation were partially inhibited by anti-LbB1LJ antibody (43-79%), which was more effective than that inhibition (18-47%) by anti-LbB2LJ antibody. In addition, the immune serum anti-LbB1LJ (67%) or anti-LbB2LJ (33%) was cytotoxic, significantly reducing the promastigotes growth in vitro. The results appoint the conserved domain from the L. braziliensis NTPDase as an important target for inhibitor design and the potential application of these biomolecules in experimental protocols of disease control. PMID:22921497

  19. 腺苷和睡眠觉醒调节%Adenosine and Sleep-Wake Regulation

    Institute of Scientific and Technical Information of China (English)

    曲卫敏; 孙宇; 许奇; 黄志力

    2011-01-01

    腺苷作为神经调质,调节多种神经生物学功能.随觉醒时间延长,动物脑内腺苷水平逐渐增高,在睡眠期显著降低.因此,腺苷被认为是调节睡眠的内稳态因子之一.腺苷受体(receptor,R)有A1R、A2AR、A2BR和A3R四种亚型,其中A1R和A2AR与诱导睡眠相关.激活A1R可抑制促觉醒神经元诱导睡眠,也可抑制促眠神经元导致觉醒,其作用存在脑区依赖性.A2AR介导内源性前列素D:的促眠作用,A2AR激动剂具有最强的促眠效应,阻断A2AR引起觉醒,在睡眠觉醒调节中扮演重要角色.本文综述腺苷调节睡眠和觉醒的研究进展,讨论腺苷受体激动剂和拮抗剂在睡眠疾病治疗中的潜在价值及存在问题.%Adenosine may function as a neuromodulator in the central nervous system. The extracellular concentration of adenosine increases in the brain during prolonged wakefulness and decreases during the sleep recovery penod. Therefore, adenosine is proposed to act as one of homeostatic regulators of sleep.There are four adenosine receptor subtypes, adenosine A1 receptor (A1R), A2AR, A2BR and A3R. Both the adenosine A1R and A2AR are demonstrated to be involved in sleep induction. Inhibition of wake-promoting neurons via the A1R mediates the sleep-inducing effects of adenosine, whereas activation of A1R in sleep-promoting neurons induces wakefulness, suggesting that A1R regulates the sleep-wake cycle in a site-dependent manner. On the other hand, the A2AR mediates the somnogenic effects of endogenous PGD2.A2AR agonist induces the most potent sleep similar to physiological sleep among somnogens reported so far,whereas blockade of A2AR induces wakefulness. Among adenosine receptors responsible for sleep induction,the role of A2AR is predominant. This paper presents an overview of the current knowledge about the role of adenosine in the sleep-wake regulation and briefly discusses the potential therapeutic applications of agonists and antagonists of these

  20. Regulation of aggregate size and pattern by adenosine and caffeine in cellular slime molds

    Directory of Open Access Journals (Sweden)

    Jaiswal Pundrik

    2012-01-01

    Full Text Available Abstract Background Multicellularity in cellular slime molds is achieved by aggregation of several hundreds to thousands of cells. In the model slime mold Dictyostelium discoideum, adenosine is known to increase the aggregate size and its antagonist caffeine reduces the aggregate size. However, it is not clear if the actions of adenosine and caffeine are evolutionarily conserved among other slime molds known to use structurally unrelated chemoattractants. We have examined how the known factors affecting aggregate size are modulated by adenosine and caffeine. Result Adenosine and caffeine induced the formation of large and small aggregates respectively, in evolutionarily distinct slime molds known to use diverse chemoattractants for their aggregation. Due to its genetic tractability, we chose D. discoideum to further investigate the factors affecting aggregate size. The changes in aggregate size are caused by the effect of the compounds on several parameters such as cell number and size, cell-cell adhesion, cAMP signal relay and cell counting mechanisms. While some of the effects of these two compounds are opposite to each other, interestingly, both compounds increase the intracellular glucose level and strengthen cell-cell adhesion. These compounds also inhibit the synthesis of cAMP phosphodiesterase (PdsA, weakening the relay of extracellular cAMP signal. Adenosine as well as caffeine rescue mutants impaired in stream formation (pde4- and pdiA- and colony size (smlA- and ctnA- and restore their parental aggregate size. Conclusion Adenosine increased the cell division timings thereby making large number of cells available for aggregation and also it marginally increased the cell size contributing to large aggregate size. Reduced cell division rates and decreased cell size in the presence of caffeine makes the aggregates smaller than controls. Both the compounds altered the speed of the chemotactic amoebae causing a variation in aggregate size

  1. Crystal structure of Escherichia coli cytidine triphosphate synthetase, a nucleotide-regulated glutamine amidotransferase/ATP-dependent amidoligase fusion protein and homologue of anticancer and antiparasitic drug targets.

    Science.gov (United States)

    Endrizzi, James A; Kim, Hanseong; Anderson, Paul M; Baldwin, Enoch P

    2004-06-01

    Cytidine triphosphate synthetases (CTPSs) produce CTP from UTP and glutamine, and regulate intracellular CTP levels through interactions with the four ribonucleotide triphosphates. We solved the 2.3-A resolution crystal structure of Escherichia coli CTPS using Hg-MAD phasing. The structure reveals a nearly symmetric 222 tetramer, in which each bifunctional monomer contains a dethiobiotin synthetase-like amidoligase N-terminal domain and a Type 1 glutamine amidotransferase C-terminal domain. For each amidoligase active site, essential ATP- and UTP-binding surfaces are contributed by three monomers, suggesting that activity requires tetramer formation, and that a nucleotide-dependent dimer-tetramer equilibrium contributes to the observed positive cooperativity. A gated channel that spans 25 A between the glutamine hydrolysis and amidoligase active sites provides a path for ammonia diffusion. The channel is accessible to solvent at the base of a cleft adjoining the glutamine hydrolysis active site, providing an entry point for exogenous ammonia. Guanine nucleotide binding sites of structurally related GTPases superimpose on this cleft, providing insights into allosteric regulation by GTP. Mutations that confer nucleoside drug resistance and release CTP inhibition map to a pocket that neighbors the UTP-binding site and can accommodate a pyrimidine ring. Its location suggests that competitive feedback inhibition is affected via a distinct product/drug binding site that overlaps the substrate triphosphate binding site. Overall, the E. coli structure provides a framework for homology modeling of other CTPSs and structure-based design of anti-CTPS therapeutics. PMID:15157079

  2. Crystal Structure of Escherichia coli Cytidine Triphosphate Synthetase, a Nucleotide-Regulated Glutamine Amidotransferase/ATP-Dependent Amidoligase Fusion Protein and Homologue of Anticancer and Antiparasitic Drug Targets†,‡

    OpenAIRE

    Endrizzi, James A.; Kim, Hanseong; Anderson, Paul M; Baldwin, Enoch P.

    2004-01-01

    Cytidine triphosphate synthetases (CTPSs) produce CTP from UTP and glutamine, and regulate intracellular CTP levels through interactions with the four ribonucleotide triphosphates. We solved the 2.3-Å resolution crystal structure of Escherichia coli CTPS using Hg-MAD phasing. The structure reveals a nearly symmetric 222 tetramer, in which each bifunctional monomer contains a dethiobiotin synthetase-like amidoligase N-terminal domain and a Type 1 glutamine amidotransferase C-terminal domain. F...

  3. Protective effects of inhibition of adenosine monophosphate activated protein kinase activity against cerebral ischemia-reperfusion injury in mice

    Institute of Scientific and Technical Information of China (English)

    补娟

    2013-01-01

    Objective To observe the effect of inhibition of adenosine monophosphate activated protein kinase (AMPK) on shape,function and inflammatory factor of microglia for mice after cerebral ischemia-reperfusion

  4. Analgesic effects of adenosine in syndrome X are counteracted by theophylline: a double-blind placebo-controlled study.

    Science.gov (United States)

    Eriksson, B E; Sadigh, B; Svedenhag, J; Sylvén, C

    2000-01-01

    It has been proposed that adenosine mediates ischaemic pain in humans. Patients with cardiac Syndrome X are hypersensitive to potential pain stimuli, including adenosine. On the other hand, recent findings suggest that low-dose adenosine infusion may have analgesic effects. Our aim was to test two hypotheses: (1) that the analgesic effect of adenosine is peripheral in origin, and (2) that part of the hypersensitivity to pain of patients with cardiac Syndrome X results from a disturbed mechanism of adenosine analgesia. A total of 12 female Syndrome X patients and eight healthy age-matched female controls were studied in a randomized, double-blind and placebo-controlled study. Adenosine (70 microg/min) or placebo was infused into the forearm via an intra-arterial catheter. After 15 min of infusion, a tourniquet on the upper arm was inflated to 225 mmHg to ensure arterial occlusion. The patient then carried out dynamic handgrip work at 60 Hz. Pain or discomfort in the forearm was estimated continuously according to the Borg CR-10 scale. After the first test, theophylline was infused for 10 min intravenously at a dose of 5 mg/kg body weight. The ischaemic forearm test was then repeated. On a second occasion, the procedure was repeated with the opposite treatment (adenosine/placebo). Only six of 12 Syndrome X patients completed the protocol because of pain during the catheterization procedure or an inability to establish an intra-arterial line. The time to onset of pain in the working, ischaemic forearm was greater for subjects treated with adenosine than for those treated with placebo, both in those Syndrome X patients who tolerated catheterization (49+/-27 s compared with 32+/-18 s; P600654

  5. Ischemic preconditioning protects post-ischemic renal function in anesthetized dogs: role of adenosine and adenine nucleotides

    Institute of Scientific and Technical Information of China (English)

    Fan-zhu LI; Shoji KIMURA; Akira NISHIYAMA; Matlubur RAHMAN; Guo-xing ZHANG; Youichi ABE

    2005-01-01

    Aim: To investigate the effects of renal ischemic preconditioning (IPC) on both renal hemodynamics and the renal interstitial concentrations of adenosine and adenine nucleotides induced by ischemia-reperfusion injury.Methods: Renal hemodynamics responses to ischemia-reperfusion injury in mongrel dog models were determined with or without multiple brief renal ischemic preconditioning treatments, as well as the adenosine A1 receptor antagonist (KW-3902),respectively.The renal interstitial concentrations of adenosine and adenine nucleotides in response to ischemia-reperfusion injury, either following 1-3 cycles of IPC or not, were measured simultaneously using microdialysis sampling technology.Results: One 10-min IPC, adenosine A1 receptor antagonist (KW3902) also shortened the recovery time of renal blood flow (RBF) and urine flow (UF), as well as mean blood pressure (BP).Advanced renal IPC attenuated the increment of adenosine and adenine nucleotides, as well as recovery time during the 60-min reperfusion which followed the 60-min renal ischemia.All of these recovery times were dependent on the cycles of 10-min IPC.The renal interstitial concentrations of adenosine and adenine nucleotides increased and decreased during renal ischemia and reperfusion, respectively.Conclusion: A significant relativity in dog models exists between the cycles of 10-min renal IPC and the recovery time of BP, UF, and RBF during the 60-min renal reperfusion following 60-min renal ischemia, respectively.Renal IPC can protect against ischemiareperfusion injury and the predominant effect of endogenous adenosine induced by prolonged renal ischemia; renal adenosine A1 receptor activation during the renal ischemia-reperfusion injury is detrimental to renal function.

  6. Impairment of ATP hydrolysis decreases adenosine A1 receptor tonus favoring cholinergic nerve hyperactivity in the obstructed human urinary bladder

    OpenAIRE

    Silva-Ramos, M.; Silva, I; Faria, M.; Magalhães-Cardoso, M. T.; Correia, J.; Ferreirinha, F; Correia-de-Sá, P.

    2015-01-01

    This study was designed to investigate whether reduced adenosine formation linked to deficits in extracellular ATP hydrolysis by NTPDases contributes to detrusor neuromodulatory changes associated with bladder outlet obstruction in men with benign prostatic hyperplasia (BPH). The kinetics of ATP catabolism and adenosine formation as well as the role of P1 receptor agonists on muscle tension and nerve-evoked [3H]ACh release were evaluated in mucosal-denuded detrusor strips from BPH patients (n...

  7. Efficient, low-cost protein factories: expression of human adenosine deaminase in baculovirus-infected insect larvae.

    OpenAIRE

    Medin, J A; Hunt, L; Gathy, K; Evans, R K; Coleman, M S

    1990-01-01

    Human adenosine deaminase (EC 3.5.4.4), a key purine salvage enzyme essential for immune competence, has been overproduced in Spodoptera frugiperda cells and in Trichoplusia ni (cabbage looper) larvae infected with recombinant baculovirus. The coding sequence of human adenosine deaminase was recombined into a baculovirus immediately downstream from the strong polyhedrin gene promoter. Approximately 60 hr after infection of insect cells with the recombinant virus, maximal levels of intracellul...

  8. Nucleoside-Derived Antagonists to A3 Adenosine Receptors Lower Mouse Intraocular Pressure and Act across Species

    OpenAIRE

    Wang, Zhao; Do, Chi Wai; Avila, Marcel Y.; Peterson-Yantorno, Kim; Stone, Richard A.; Gao, Zhan-Guo; Joshi, Bhalchandra; Besada, Pedro; Jeong, Lak Shin; Jacobson, Kenneth A.; Civan, Mortimer M.

    2009-01-01

    The purpose of the study was to determine whether novel, selective antagonists of human A3 adenosine receptors (ARs) derived from the A3-selective agonist Cl-IB-MECA lower intraocular pressure (IOP) and act across species. IOP was measured invasively with a micropipette by the Servo-Null Micropipette System (SNMS) and by non-invasive pneumotonometry during topical drug application. Antagonist efficacy was also assayed by measuring inhibition of adenosine-triggered shrinkage of native bovine n...

  9. Activation of NTS A(1) adenosine receptors inhibits regional sympathetic responses evoked by activation of cardiopulmonary chemoreflex.

    Science.gov (United States)

    Ichinose, Tomoko K; Minic, Zeljka; Li, Cailian; O'Leary, Donal S; Scislo, Tadeusz J

    2012-09-01

    Previously we have shown that adenosine operating via the A(1) receptor subtype may inhibit glutamatergic transmission in the baroreflex arc within the nucleus of the solitary tract (NTS) and differentially increase renal (RSNA), preganglionic adrenal (pre-ASNA), and lumbar (LSNA) sympathetic nerve activity (ASNA>RSNA≥LSNA). Since the cardiopulmonary chemoreflex and the arterial baroreflex are mediated via similar medullary pathways, and glutamate is a primary transmitter in both pathways, it is likely that adenosine operating via A(1) receptors in the NTS may differentially inhibit regional sympathetic responses evoked by activation of cardiopulmonary chemoreceptors. Therefore, in urethane-chloralose-anesthetized rats (n = 37) we compared regional sympathoinhibition evoked by the cardiopulmonary chemoreflex (activated with right atrial injections of serotonin 5HT(3) receptor agonist phenylbiguanide, PBG, 1-8 μg/kg) before and after selective stimulation of NTS A(1) adenosine receptors [microinjections of N(6)-cyclopentyl adenosine (CPA), 0.033-330 pmol/50 nl]. Activation of cardiopulmonary chemoreceptors evoked differential, dose-dependent sympathoinhibition (RSNA>ASNA>LSNA), and decreases in arterial pressure and heart rate. These differential sympathetic responses were uniformly attenuated in dose-dependent manner by microinjections of CPA into the NTS. Volume control (n = 11) and blockade of adenosine receptor subtypes in the NTS via 8-(p-sulfophenyl)theophylline (8-SPT, 1 nmol in 100 nl) (n = 9) did not affect the reflex responses. We conclude that activation of NTS A(1) adenosine receptors uniformly inhibits neural and cardiovascular cardiopulmonary chemoreflex responses. A(1) adenosine receptors have no tonic modulatory effect on this reflex under normal conditions. However, when adenosine is released into the NTS (i.e., during stress or severe hypotension/ischemia), it may serve as negative feedback regulator for depressor and sympathoinhibitory reflexes

  10. Adenosine kinase deficiency with neurodevelopemental delay and recurrent hepatic dysfunction: A case report

    Science.gov (United States)

    Shakiba, Marjan; Mahjoub, Fatemeh; Fazilaty, Hassan; Rezagholizadeh, Fereshteh; Shakiba, Arghavan; Ziadlou, Maryam; Gahl, William A.; Behnam, Babak

    2016-01-01

    Hypermethioninemia may be benign, present as a nonspecific sign of nongenetic conditions such as liver failure and prematurity, or a severe, progressive inborn error of metabolism. Genetic causes of hypermethioninemia include mitochondrial depletion syndromes caused by mutations in the MPV17 and DGUOK genes and deficiencies of cystathionine β-synthase, methionine adenosyltransferase types I and III, glycine N-methyltransferase, S-adenosylhomocysteine hydrolase, citrin, fumarylacetoacetate hydrolase, and adenosine kinase. Here we present a 3-year old girl with a history of poor feeding, irritability, respiratory infections, cholestasis, congenital heart disease, neurodevelopmental delay, hypotonia, sparse hair, facial dysmorphisms, liver dysfunction, severe hypermethioninemia and mild homocystinemia. Genetic analysis of the adenosine kinase (ADK) gene revealed a previously unreported variant (c.479–480 GA>TG) resulting in a stop codon (p.E160X) in ADK. A methionine-restricted diet normalized the liver function test results and improved her hypotonia. PMID:27500280

  11. Alteration of membrane phospholipid methylation by adenosine analogs does not affect T lymphocyte activation

    International Nuclear Information System (INIS)

    Membrane phospholipid methylation has been described during activation of various immune cells. Moreover recent data indicated modulation of immune cells functions by adenosine. As S-adenosyl-methionine and S-adenosyl-homocysteine are adenosine analogs and modulators of transmethylation reactions, the effects of SAH and SAM were investigated on membrane phospholipid methylation and lymphocyte activation. SAM was shown to induce the membrane phospholipid methylation as assessed by the 3Hmethyl-incorporation in membrane extract. This effect was inhibited by SAH. In contrast SAM and SAH did not affect the phytohemagglutinin-induced proliferative response of peripheral blood mononuclear cells. SAH neither modified the early internalization of membrane CD3 antigens nor did it prevent the late expression of HLA-DR antigens on lymphocytes activated by phytohemagglutinin. These results indicate that in vitro alteration of phospholipid methylation does not affect subsequent steps of human T lymphocyte activation and proliferation

  12. Synthesis and Pharmacological Evaluation of Modified Adenosines Joined to Mono-Functional Platinum Moieties

    Directory of Open Access Journals (Sweden)

    Stefano D'Errico

    2014-07-01

    Full Text Available The synthesis of four novel platinum complexes, bearing N6-(6-amino-hexyladenosine or a 1,6-di(adenosin-N6-yl-hexane respectively, as ligands of mono-functional cisplatin or monochloro(ethylendiamineplatinum(II, is reported. The chemistry exploits the high affinity of the charged platinum centres towards the N7 position of the adenosine base system and a primary amine of an alkyl chain installed on the C6 position of the purine. The cytotoxic behaviour of the synthesized complexes has been studied in A549 adenocarcinomic human alveolar basal epithelial and MCF7 human breast adenocarcinomic cancer cell lines, in order to investigate their effects on cell viability and proliferation.

  13. Platelet aggregation and serum adenosine deaminase (ADA) activity in pregnancy associated with diabetes, hypertension and HIV.

    Science.gov (United States)

    Leal, Claudio A M; Leal, Daniela B R; Adefegha, Stephen A; Morsch, Vera M; da Silva, José E P; Rezer, João F P; Schrekker, Clarissa M L; Abdalla, Faida H; Schetinger, Maria R C

    2016-07-01

    Platelet aggregation and adenosine deaminase (ADA) activity were evaluated in pregnant women living with some disease conditions including hypertension, diabetes mellitus and human immunodeficiency virus infection. The subject population is consisted of 15 non-pregnant healthy women [control group (CG)], 15 women with normal pregnancy (NP), 7 women with hypertensive pregnancy (HP), 10 women with gestational diabetes mellitus (GDM) and 12 women with human immunodeficiency virus-infected pregnancy (HIP) groups. The aggregation of platelets was checked using an optical aggregometer, and serum ADA activity was determined using the colorimetric method. After the addition of 5 µM of agonist adenosine diphosphate, the percentage of platelet aggregation was significantly (p pregnancy and pregnancy-associated diseases suggest that platelet aggregation and ADA activity could serve as peripheral markers for the development of effective therapy in the maintenance of homeostasis and some inflammatory process in these pathophysiological conditions. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27273565

  14. Adenosine A2B receptor: from cell biology to human diseases

    Science.gov (United States)

    Sun, Ying; Huang, Pingbo

    2016-08-01

    Extracellular adenosine is a ubiquitous signaling molecule that modulates a wide array of biological processes. Recently, significant advances have been made in our understanding of A2B adenosine receptor (A2BAR). In this review, we first summarize some of the general characteristics of A2BAR, and then we describe the multiple binding partners of the receptor, such as newly identified α-actinin-1 and p105, and discuss how these associated proteins could modulate A2BAR’s functions, including certain seemingly paradoxical functions of the receptor. Growing evidence indicates a critical role of A2BAR in cancer, renal disease, and diabetes, in addition to its importance in the regulation of vascular diseases and lung disease. Here, we also discuss the role of A2BAR in cancer, renal disease, and diabetes and the potential of the receptor as a target for treating these three diseases.

  15. A Case of Hypogammaglobulinemia with Enteroviral Meningoencephalitis, Associated with Increased Adenosine Deaminase in Cerebrospinal Fluid

    Directory of Open Access Journals (Sweden)

    Alborizi Abdolvahab

    2009-06-01

    Full Text Available We describe the development of enterovirus meningoencephalitis associated with increased adenosine deaminase in cerebrospinal fluid of a 12-year-old boy, a known case of hypogamaglobulinemia despite monthly replacement of IVIg.The patient was referred to our center with fever, headache and vomiting for 10 days. CSF analysis was compatible with aseptic meningoencephalitis but high CSF protein (>200mg/dl and high level of adenosine deaminase in CSF (30IU/L were against the diagnosis of simple viral meningoencephalitis. Nested PCR of CSF for entrovirus was positive. Treatment with daily high-dose IVIg was commenced, with significant clinical improvement. For patients with increased ADA and lymphocytic pleocytosis in CSF, differential diagnoses should include enteroviral meningitis. Antibodies, although crucial, cannot on their own prevent enteroviral infection in some hypogamaglbulinemic patients.

  16. Adenosine deaminase complexing protein (ADCP): a transformation sensitive protein with potentials of a cancer marker.

    Science.gov (United States)

    Herbschleb-Voogt, E; Ten Kate, J; Meera Khan, P

    1983-01-01

    Several observations by independent investigators in the past have indicated that adenosine deaminase complexing protein (ADCP), present in considerable quantities in certain human tissues, was absent or decreased in the cancers originated from them. During the present study, electrophoretic analysis of adenosine deaminase (ADA) isozymes and radioimmunoassay for ADCP in the primary fibroblasts and the transformed as well as certain tumor derived cell lines have demonstrated that ADCP present in large quantities in the primary cells was absent or nearly absent in the transformed or tumor-derived cell lines. Though the mechanisms involved are not yet clear, the above observations indicate that ADCP has the potentials of a useful marker in the studies on transformed cells and cancer tissues. PMID:6133497

  17. GIRK channel activation via adenosine or muscarinic receptors has similar effects on rat atrial electrophysiology

    DEFF Research Database (Denmark)

    Wang, Xiaodong; Liang, Bo; Skibsbye, Lasse;

    2013-01-01

    and compare the electrophysiological effects of acetylcholine (ACh) and adenosine on GIRK channels in rat atria. Action potential duration at 90% repolarization (APD90), effective refractory period (ERP), and resting membrane potential (RMP) were investigated in isolated rat atria by intracellular recordings....... Both the adenosine analog N6-cyclopentyladenosine (CPA) and ACh profoundly shortened APD90 and ERP and hyperpolarized the RMP. No additive or synergistic effect of CPA and ACh coapplication was observed. To antagonize GIRK channel activation, the specific inhibitor rTertiapin Q (TTQ) was applied....... The coapplication of TTQ reversed the CPA and ACh-induced effects. When TTQ was applied without exogenous receptor activator, both APD90 and ERP were prolonged and RMP was depolarized, confirming a basal activity of the GIRK current. The results reveal that activation of A1 and M2 receptors has a profound and equal...

  18. Tumour necrosis factor-α and adenosine in endotoxin shockleading related cardiovascular symptoms

    Directory of Open Access Journals (Sweden)

    S. Sipka

    1995-01-01

    Full Text Available We have observed uncontrollable cardiogenic shock as a cardiovascular manifestation of systemic inflammatory response syndrome (SIRS leading to death in a 62-year-old woman. The diagnosis of SIRS was based on the demonstration of endotoxinaemia, and highly elevated plasma levels of tumour necrosis factor (TNF-α, and interleukin (IL-10. We suggest that these cytokines may contribute to the terminal SIRS-related arrythmias, impaired myocardial contractility, as well as increased vascular permeability. In addition, the increased production of adenosine, a counter-regulatory mediator of inflammation, may also play a role in cardiodepression. We suggest a relationship between the action of TNF-α , IL-10 and adenosine in the pathogenesis of circulatory symptoms described above.

  19. Molecular Pathways of Disturbed Sleep and Depression: Studies on Adenosine and Gene Expression Patterns

    OpenAIRE

    Gass, Natalia

    2010-01-01

    Background: Adenosine is a potent sleep-promoting substance, and one of its targets is the basal forebrain. Fairly little is known about its mechanism of action in the basal forebrain and about the receptor subtype mediating its regulating effects on sleep homeostasis. Homeostatic deficiency might be one of the causes of the profoundly disturbed sleep pattern in major depressive disorder, which could explain the reduced amounts of delta-activity-rich stages 3 and 4. Since major depression has...

  20. Respiratory activity in medulla oblongata and its modulation by adenosine and opioids

    OpenAIRE

    Herlenius, Eric

    1998-01-01

    From the moment of birth the complex neuronal networks generating breathing has to function continuously and adapt to the new postnatal environmental demands. This thesis aims at studying the perinatal development of respiratory control and its modulation by adenosine and opioids. Respiratory activity was studied in vitro using brainstem spinal cord preparations and in vivo with a barometric plethysmograph. In vitro whole-cell patch clamp recordings of respiratory related ne...

  1. Adenosine receptors in the immature brain : with special reference to their role in hypoxic ischemia

    OpenAIRE

    Ådén, Ulrika

    2001-01-01

    Although the newborn brain tolerates a much longer period of oxygen deprivation and ischemia than does the adult brain, perinatal hypoxic ischemia probably is an important cause of neurological dysfunction, cerebral palsy and epilepsy later in life. Hence it is important to investigate the mechanisms that modulate the extent of perinatal ischernic brain damage. There is good evidence that endogenous adenosine acts as a neuroprotective agent in models of ischemia in the m...

  2. A Review of Tandem Mass Spectrometry Characterization of Adenosine Diphosphate-Ribosylated Peptides

    OpenAIRE

    Hengel, Shawna M.; Goodlett, David R.

    2011-01-01

    The use of tandem mass spectrometry to identify and characterize sites of protein adenosine diphosphate (ADP) ribosylation will be reviewed. Specifically, we will focus on data acquisition schemes and fragmentation techniques that provide peptide sequence and modification site information. Also discussed are uses of synthetic standards to aid characterization, and an enzymatic method that converts ADP-ribosylated peptides into ribosyl mono phosphorylated peptides making identification amenabl...

  3. Autoimmune dysregulation and purine metabolism in adenosine deaminase (ADA)-deficiency

    OpenAIRE

    Aisha Vanessa Sauer; Immacolata eBrigida; Nicola eCarriglio; Alessandro eAiuti

    2012-01-01

    Genetic defects in the adenosine deaminase (ADA) gene are among the most common causes for severe combined immunodeficiency (SCID). ADA-SCID patients suffer from lymphopenia, severely impaired cellular and humoral immunity, failure to thrive and recurrent infections. Currently available therapeutic options for this otherwise fatal disorder include bone marrow transplantation (BMT), enzyme replacement therapy with bovine ADA (PEG-ADA) or hematopoietic stem cell gene therapy (HSC-GT). Although ...

  4. Adenosine kinase inhibition protects against cranial radiation-induced cognitive dysfunction

    Directory of Open Access Journals (Sweden)

    Munjal M Acharya

    2016-06-01

    Full Text Available Clinical radiation therapy for the treatment of CNS cancers leads to unintended and debilitating impairments in cognition. Radiation-induced cognitive dysfunction is long lasting, however, the underlying molecular and cellular mechanisms are still not well established. Since ionizing radiation causes microglial and astroglial activation, we hypothesized that maladaptive changes in astrocyte function might be implicated in radiation-induced cognitive dysfunction. Among other gliotransmitters, astrocytes control the availability of adenosine, an endogenous neuroprotectant and modulator of cognition, via metabolic clearance through adenosine kinase (ADK. Adult rats exposed to cranial irradiation (10 Gy showed significant declines in performance of hippocampal-dependent cognitive function tasks (novel place recognition, novel object recognition, and contextual fear conditioning 1 month after exposure to ionizing radiation using a clinically relevant regimen. Irradiated rats spent less time exploring a novel place or object. Cranial irradiation also led to reduction in freezing behavior compared to controls in the fear conditioning task. Importantly, immunohistochemical analyses of irradiated brains showed significant elevation of ADK immunoreactivity in the hippocampus that was related to astrogliosis and increased expression of glial fibrillary acidic protein (GFAP. Conversely, rats treated with the ADK inhibitor 5-iodotubercidin (5-ITU, 3.1 mg/kg, i.p., for 6 days prior to cranial irradiation showed significantly improved behavioral performance in all cognitive tasks 1 month post exposure. Treatment with 5-ITU attenuated radiation-induced astrogliosis and elevated ADK immunoreactivity in the hippocampus. These results confirm an astrocyte-mediated mechanism where preservation of extracellular adenosine can exert neuroprotection also against radiation-induced pathology. These innovative findings link radiation-induced changes in cognition and CNS

  5. The effects of adenosine on plasma homocysteine levels and some other biochemical parameters

    OpenAIRE

    Turgut, Günfer; Rota, Simin; Aybek, Hülya; Turgut, Sebahat; Sert, Seelahattin; Genç, Osman

    2009-01-01

    Süleyman Demirel Üniversitesi TIP FAKÜLTESİ DERGİSİ: 2007 Aralık; 14(4) The effects of adenosine on plasma homocysteine levels and some other biochemical parameters Günfer Turgut*, Simin Rota**, Hülya Aybek**, Sebahat Turgut*, Selahattin Sert**, Osman Genç* *Pamukkale University Faculty of Medicine Departments of Physiology, Denizli, Turkey **Pamukkale University,Faculty of Medicine, Departments of Biochemistry Denizl...

  6. CD73-mediated adenosine production promotes stem cell-like properties in mouse Tc17 cells.

    Science.gov (United States)

    Flores-Santibáñez, Felipe; Fernández, Dominique; Meza, Daniel; Tejón, Gabriela; Vargas, Leonardo; Varela-Nallar, Lorena; Arredondo, Sebastián; Guixé, Victoria; Rosemblatt, Mario; Bono, María Rosa; Sauma, Daniela

    2015-12-01

    The CD73 ectonucleotidase catalyses the hydrolysis of AMP to adenosine, an immunosuppressive molecule. Recent evidence has demonstrated that this ectonucleotidase is up-regulated in T helper type 17 cells when generated in the presence of transforming growth factor-β (TGF-β), and hence CD73 expression is related to the acquisition of immunosuppressive potential by these cells. TGF-β is also able to induce CD73 expression in CD8(+) T cells but the function of this ectonucleotidase in CD8(+) T cells is still unknown. Here, we show that Tc17 cells present high levels of the CD73 ectonucleotidase and produce adenosine; however, they do not suppress the proliferation of CD4(+) T cells. Interestingly, we report that adenosine signalling through A2A receptor favours interleukin-17 production and the expression of stem cell-associated transcription factors such as tcf-7 and lef-1 but restrains the acquisition of Tc1-related effector molecules such as interferon-γ and Granzyme B by Tc17 cells. Within the tumour microenvironment, CD73 is highly expressed in CD62L(+) CD127(+) CD8(+) T cells (memory T cells) and is down-regulated in GZMB(+) KLRG1(+) CD8(+) T cells (terminally differentiated T cells), demonstrating that CD73 is expressed in memory/naive cells and is down-regulated during differentiation. These data reveal a novel function of CD73 ectonucleotidase in arresting CD8(+) T-cell differentiation and support the idea that CD73-driven adenosine production by Tc17 cells may promote stem cell-like properties in Tc17 cells. PMID:26331349

  7. [Concentration of prostaglandins and cyclic adenosine-3',5'-monophosphate in the tissues of rats].

    Science.gov (United States)

    Komissarenko, V P; Slavnov, V N; Epsheĭn, E V; Malinkovich, V D

    1977-04-01

    The content of prostaglandines (PG) and cyclic 3',5'-adenosine monphosphate (cAMP) was investigated in rat tissues by the radioisotopic method of competitive binding. Maximum quantities of both PG and cAMP were revealed in the same most actively functioning organs: the brain, incretory glands, small intestine. Fatty tissue showed minimum quantities of these substances. Results indicate a close functional relationship between the PG synthesis and adenylatecyclase activity in the body tissues.

  8. Molecular structural investigation of adenosine using spectroscopic and quantum computational calculations

    Science.gov (United States)

    Bakkiyaraj, D.; Periandy, S.; Xavier, S.

    2016-09-01

    In this study; spectroscopic investigation of adenosine having clinical importance was studied computationally and obtained results were compared with experimental ones. In this scope, geometric optimization and conformational analysis were studied and vibrational spectroscopic properties were studied on the most stable form. NMR and TD-DFT studies on the title compound were conducted with its experimental data. In addition atomic charge distribution, NBO, frontier molecular analysis, thermodynamic analysis and hyperpolarization features were studied.

  9. Photophysical processes of the spectroscopic RNA probe 2-(1-ethynylpyrene-adenosine (PyA

    Directory of Open Access Journals (Sweden)

    Engels J.

    2013-03-01

    Full Text Available We examine the photoinduced excited state dynamics of pyrene modified adenosine, a versatile probe for folding and hybridization of ribonucleic acids. Measurements in different solvents revealed complex ultrafast dynamics, but high robustness since the overall fluorescence quantum yield (Φf is hardly affected. The result is a strong fluorescent RNA-probe whose spectral properties change in a defined way upon environmental changes.

  10. Adenosine activates brown adipose tissue and recruits beige adipocytes via A2A receptors

    DEFF Research Database (Denmark)

    Gnad, Thorsten; Scheibler, Saskia; von Kügelgen, Ivar;

    2014-01-01

    Brown adipose tissue (BAT) is specialized in energy expenditure, making it a potential target for anti-obesity therapies. Following exposure to cold, BAT is activated by the sympathetic nervous system with concomitant release of catecholamines and activation of β-adrenergic receptors. Because BAT...... that adenosine-A2A signalling plays an unexpected physiological role in sympathetic BAT activation and protects mice from diet-induced obesity. Those findings reveal new possibilities for developing novel obesity therapies....

  11. Development of gene therapy: potential in severe combined immunodeficiency due to adenosine deaminase deficiency.

    OpenAIRE

    Montiel-Equihua, Claudia A; Thrasher, Adrian J.; Bobby Gaspar, H

    2009-01-01

    Claudia A Montiel-Equihua, Adrian J Thrasher, H Bobby GasparCentre for Immunodeficiency, Molecular Immunology Unit, UCL Institute of Child Health, London, UKAbstract: The history of stem cell gene therapy is strongly linked to the development of gene therapy for severe combined immunodeficiencies (SCID) and especially adenosine deaminase (ADA)-deficient SCID. Here we discuss the developments achieved in over two decades of clinical and laboratory research that led to the establishment of a pr...

  12. Development of gene therapy: potential in severe combined immunodeficiency due to adenosine deaminase deficiency

    OpenAIRE

    Thrasher, Adrian

    2009-01-01

    Claudia A Montiel-Equihua, Adrian J Thrasher, H Bobby GasparCentre for Immunodeficiency, Molecular Immunology Unit, UCL Institute of Child Health, London, UKAbstract: The history of stem cell gene therapy is strongly linked to the development of gene therapy for severe combined immunodeficiencies (SCID) and especially adenosine deaminase (ADA)-deficient SCID. Here we discuss the developments achieved in over two decades of clinical and laboratory research that led to the establishment of a pr...

  13. The in vivo respiratory phenotype of the adenosine A1 receptor knockout mouse.

    Science.gov (United States)

    Heitzmann, Dirk; Buehler, Philipp; Schweda, Frank; Georgieff, Michael; Warth, Richard; Thomas, Joerg

    2016-02-01

    The nucleoside adenosine has been implicated in the regulation of respiration, especially during hypoxia in the newborn. In this study the role of adenosine A1 receptors for the control of respiration was investigated in vivo. To this end, respiration of unrestrained adult and neonatal adenosine A1 receptor knockout mice (A1R(-/-)) was measured in a plethysmographic device. Under control conditions (21% O2) and mild hypoxia (12-15% O2) no difference of respiratory parameters was observed between adult wildtype (A1R(+/+)) and A1R(-/-) mice. Under more severe hypoxia (6-10% O2) A1R(+/+) mice showed, after a transient increase of respiration, a decrease of respiration frequency (fR) and tidal volume (VT) leading to a decrease of minute volume (MV). This depression of respiration during severe hypoxia was absent in A1R(-/-) mice which displayed a stimulated respiration as indicated by the enhancement of MV by some 50-60%. During hypercapnia-hyperoxia (3-10% CO2/97-90 % O2), no obvious differences in respiration of A1R(-/-) and A1R(+/+) was observed. In neonatal mice, the respiratory response to hypoxia was surprisingly similar in both genotypes. However, neonatal A1R(-/-) mice appeared to have more frequently periods of apnea during hypoxia and in the post-hypoxic control period. In conclusion, these data indicate that the adenosine A1 receptor is an important molecular component mediating hypoxic depression in adult mice and it appears to stabilize respiration of neonatal mice. PMID:26593641

  14. Inhibition of adenosine deaminase (ADA)-mediated metabolism of cordycepin by natural substances

    OpenAIRE

    Li, Gen; Nakagome, Izumi; Hirono, Shuichi; Itoh, Tomoo; Fujiwara, Ryoichi

    2015-01-01

    Cordycepin, which is an analogue of a nucleoside adenosine, exhibits a wide variety of pharmacological activities including anticancer effects. In this study, ADA1- and ADA2-expressing HEK293 cells were established to determine the major ADA isoform responsible for the deamination of cordycepin. While the metabolic rate of cordycepin deamination was similar between ADA2-expressing and Mock cells, extensive metabolism of cordycepin was observed in the ADA1-expressing cells with K m and V max v...

  15. Pulmonary Vascular Capacitance as a Predictor of Vasoreactivity in Idiopathic Pulmonary Arterial Hypertension Tested by Adenosine

    OpenAIRE

    Shafie, Davood; Dohaei, Abolfazl; AMIN, Ahmad; Taghavi, Sepideh; Naderi, Nasim

    2015-01-01

    Background: Acute pulmonary vasoreactivity testing has been recommended in the diagnostic work-up of patients with idiopathic pulmonary arterial hypertension (IPAH). Pulmonary arteriolar capacitance (Cp) approximated by stroke volume divided by pulmonary pulse pressure (SV/PP) is considered as an independent predictor of mortality in patients with IPAH. Objectives: We sought to evaluate any differences in baseline and adenosine Cp between vasoreactive and non-vasoreactive IPAH patients tested...

  16. Adenosine Preconditioning versus Ischemic Preconditioning in Patients undergoing Off-Pump Coronary Artery Bypass (OPCAB

    Directory of Open Access Journals (Sweden)

    SeyedKhalil Forouzannia

    2015-10-01

    Full Text Available Background: During off-pump coronary artery bypass (OPCAB, the heart is subjected to ischemic and reperfusion injury. Preconditioning is a mechanism that permits the heart to tolerate myocardial ischemia. The aim of this study was to compare the effects of Adenosine preconditioning with ischemic preconditioning on the global ejection fraction (EF in patients undergoing OPCAB.Methods: In this single-blind, randomized controlled trial, sixty patients undergoing OPCAB were allocated into three equally-numbered groups through simple randomization: Adenosine group, ischemic group, and control group. The patients in the Adenosine group received an infusion of Adenosine. In the ischemic group, ischemic preconditioning was induced by the temporary occlusion of the left anterior descending coronary artery twice for a 2-minute period, followed by 3-minute reperfusion before bypass grafting of the first coronary vessel. The control group received an intravenous infusion of 0.9% saline. Blood samples at different times were sent for the measurement of creatine kinase isoenzyme MB (CK-MB and cardiac troponin I (cTnI. We also recorded electrocardiographic indices and clinical parameters, including postoperative use of inotropic drugs and preoperative and postoperative EF.Results: History of myocardial infarction, hyperlipidemia, diabetes mellitus, kidney disease, preoperative arrhythmias, and utilization of postoperative inotrope was the same between the three groups. The incidence of postoperative arrhythmias was not significant between the three groups. Also, there were no significant differences in preoperative and postoperative EF and the serum levels of enzymes (cTnI and CK-MB between the groups.Conclusion: Based on the findings of this study, there was no significant difference in the postoperative EF between the groups. Although the incidence of arrhythmias was higher in the ischemic preconditioning group than in the other groups, the difference

  17. Outcome of Patients With Adenosine-Induced ST Segment Depression and Normal Myocardial Perfusion

    International Nuclear Information System (INIS)

    The aim of the present study was to determine the outcome of patients with normal MPS and adenosine-induced ST segment depression. A total of 1867 patients underwent adenosine Tc99m-tetrofosmin MPS in nuclear medicine unit in Saudi German Hospital, Saudi Arabia, between January 2004 and May 2008. Their ECGs were checked for ST segment depression during adenosine infusion. All patients with ≥ 1 mm horizontal or down-sloping ST segment depression or≥ 1.5 mm up-sloping ST segment depression were included in the study. Fifty-six patients met our inclusion criteria, of which 45 (80%) were females. During the follow-up period, a total of 15 of patients ended up doing coronary angiography, either for high clinical suspicion or following a second positive MPS performed 6-18 months after the first study. Seven of them were positive for coronary artery disease and were subsequently treated with revascularization procedure, and 8 returned either normal angiography or non-obstructive coronary artery disease. Male diabetic smoking patients were more prevalent and underwent revascularization. The patients were followed up for a mean of 22.8 ±7.8 months. No cardiac deaths or myocardial infarctions were reported. It could be concluded that adenosine-induced ST segment depression in patients with normal myocardial perfusion was a benign finding and did not increase the very low risk of cardiac events in those patients. However, male smokers and/or diabetics might need further investigation. This suggestion needs further evaluation

  18. Cellular mechanisms for the treatment of chronic heart failure: the nitric oxide- and adenosine-dependent pathways.

    Science.gov (United States)

    Minamino, Tetsuo; Kitakaze, Masafumi

    2002-05-01

    Accumulated evidence suggests that several drugs proven to improve survival in patients with chronic heart failure (CHF) enhance endogenous nitric oxide (NO)- and/or adenosine-dependent pathways. Indeed, we and others have demonstrated that: i) antagonists of either renin-angiotensin-aldosterone or beta-adrenergic systems enhance NO-dependent pathways; ii) although carvedilol and amlodipine belong to different drug classes, both of them can increase cardiac adenosine levels; iii) increased adenosine levels by dipyridamole are associated with the improvement of CHF. Interestingly, both NO and adenosine have multifactorial beneficial actions in cardiovascular systems. First of all, both of them induce vasodilation and decrease myocardial hypercontractility, which may contribute to a reduction in the severity of myocardial ischaemia. Both adenosine and NO are also involved in cardioprotection attributable to acute and late phases of ischaemic preconditioning, respectively. Secondly, they can modulate the neurohormonal systems that contribute to the progression of CHF. Thus, we propose that enhancement of endogenous NO and/or adenosine as potential therapeutic targets in a new strategy for the treatment for CHF. PMID:15989539

  19. [Thallium-201 myocardial perfusion imaging during adenosine-induced coronary vasodilation in patients with ischemic heart disease].

    Science.gov (United States)

    Takeishi, Y; Chiba, J; Abe, S; Ikeda, K; Tonooka, I; Komatani, A; Takahashi, K; Nakagawa, Y; Shiraishi, T; Tomoike, H

    1992-09-01

    201Tl myocardial perfusion imaging during adenosine infusion was performed in consecutive 55 patients with suspected coronary artery disease. Adenosine was infused intravenously at a rate of 0.14 mg/kg/min for 6 minutes and a dose of 111 MBq of 201Tl was administered in a separate vein at the end of third minute of infusion. Myocardial SPECT imaging was begun 5 minutes and 3 hours after the end of adenosine infusion. For evaluating the presence of perfusion defects, 2 short axis images at the basal and apical levels and a vertical long axis image at the mid left ventricle were used. The regions with decreased 201Tl uptake were assessed semi-quantitatively. Adenosine infusion caused a slight reduction in systolic blood pressure and an increase in heart rate. The rate pressure products increased slightly (9314 +/- 2377 vs. 10360 +/- 2148, p < 0.001). Chest pain (24%) and headache (13%) were the frequent side effects. The second-degree atrioventricular block was developed in 11 of 55 (20%) patients. All symptoms and hemodynamic changes were well tolerated and disappeared within 1 or 2 minutes after discontinuing adenosine infusion. The sensitivity and specificity for the detection of patients with coronary artery disease were 100% (31/31) and 88% (7/8), respectively. 201Tl myocardial imaging during adenosine infusion was considered to be safe and useful for evaluating the patients with ischemic heart disease. PMID:1453559

  20. Effect of 2-(6-cyano-1-hexyn-1-yl)adenosine on ocular blood flow in rabbits.

    Science.gov (United States)

    Konno, Takashi; Uchibori, Takehiro; Nagai, Akihiko; Kogi, Kentaro; Nakahata, Norimichi

    2007-02-27

    Previously, we reported that a relatively selective adenosine A(2A) receptor agonist 2-(6-cyano-1-hexyn-1-yl)adenosine (2-CN-Ado) elicited ocular hypotension in rabbits (Journal of Pharmacological Sciences 2005;97:501-509). In the present study, we investigated the effect of 2-CN-Ado on ocular blood flow in rabbit eyes. An intravitreal injection of 2-CN-Ado increased ocular blood flow, measured by a non-contact laser flowmeter. 2-CN-Ado-induced increase in ocular blood flow was accompanied with the retinal vasodilation. The increase in ocular blood flow was inhibited by an adenosine A(2A) receptor antagonist 1,3,7-trimethyl-8-(3-chlorostyryl)xanthine, but not by an adenosine A(2B) receptor antagonist alloxazine or an adenosine A(1) receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine. The repetitive applications of topical 2-CN-Ado twice a day for 7 days produced a persistent increase in ocular blood flow with ocular hypotension. These results suggest that 2-CN-Ado increases the ocular blood flow mainly via adenosine A(2A) receptor, and that the topical application of 2-CN-Ado for several days not only increases the ocular blood flow but also prolong ocular hypotension, indicating that 2-CN-Ado may be a useful lead compound for the treatment of ischemic retinal diseases such as glaucoma.

  1. Comparison of adenosine and exercise stress 201Tl myocardial perfusion imaging for diagnosing coronary heart disease in women

    International Nuclear Information System (INIS)

    Objective: To compare the diagnostic value of adenosine and exercise stress myocardial perfusion imaging (MPI) for detecting coronary heart disease (CHD) in women. Methods: One hundred and thirty-eight patients with CHD were randomly divided into two groups: adenosine stress group (n=69)and exercise stress group (n=69). All patients underwent myocardial SPECT evaluation. Coronary angiography (CAG), referred as 'gold standard' , was performed in each patient within 1 week before or after MPI. The diagnostic value of the two stress MPI was compared with χ2 test or Fisher's exact test. Results: In adenosine stress group, the sensitivity, negative predictive value and accuracy were 88.2% (45/51), 72.7% (16/22), 88.4% (61/69), respectively, which were not significantly different from those of the exercise stress group (91.7% (44/48), 66.7% (8/12), 81.2% (52/64); χ2 =0.571, 0.714, 0.249, P>0.05). However, the false positive rate of adenosine stress (11.1%, 2/18) was significantly lower than that of exercise stress (50.0%, 8/16), P=0.023. Conclusions: Adenosine and exercise stress MPI have similar value for CHD diagnosis in women, however, adenosine stress MPI may have an advantage of low false positive rate. (authors)

  2. Value of the adenosine test for diagnosis of dual AV nodal physiology in patients with AV nodal reentrant tachycardia

    Institute of Scientific and Technical Information of China (English)

    周斌全; 胡申江; 鲁端; 王建安

    2002-01-01

    Objectives: This study was aimed at assessing the value of the adenosine test for noninvasive diagnosis of dual AV nodal physiology(DAVNP) in patients with AV nodal reentrant tachycardia (AVNRT). Methods: 53 patients with paroxysmal supraventricular tachycardia (PSVT) were given incremental doses of adenosine intravenously during sinus rhythm before electrophysiological study. The adenosine test was repeated on a subset of 18 patients with AVNRT after radiofrequency catheter ablation. Results: Sudden increments of PR interval of more than 60 msec between two consecutive beats were observed in 26(83.9%) of 31 patients with typical AVNRT and 2 (9.1%) of 22 patients with AVRT and AT (P<0.01). The maximal PR increment between 2 consecutive beats in the AVNRT group(105±45ms) was significantly greater than that in the AVRT and AT group (20±13ms) (P<0.01).In postablation adenosine test, DAVNP was eliminated in all 8 patients who underwent slow pathway abolition that EPS showed the slow pathway disappeared and 4 of 10 patients who underwent slow pathway modification that EPS showed the slow pathway persisted. Six of 10 patients who exhibited persistent duality showed a marked reduction in the number of beats conducted in the slow pathway after adenosine injection(P<0.01).Conclusions: Administration of adenosine during sinus rhythm may be a useful bedside test for diagnosis of DAVNP in high percentage of patients with typical AVNRT and additionally for evaluating the effects of radiofrequency ablation.

  3. Effect of 2-(6-cyano-1-hexyn-1-yl)adenosine on ocular blood flow in rabbits.

    Science.gov (United States)

    Konno, Takashi; Uchibori, Takehiro; Nagai, Akihiko; Kogi, Kentaro; Nakahata, Norimichi

    2007-02-27

    Previously, we reported that a relatively selective adenosine A(2A) receptor agonist 2-(6-cyano-1-hexyn-1-yl)adenosine (2-CN-Ado) elicited ocular hypotension in rabbits (Journal of Pharmacological Sciences 2005;97:501-509). In the present study, we investigated the effect of 2-CN-Ado on ocular blood flow in rabbit eyes. An intravitreal injection of 2-CN-Ado increased ocular blood flow, measured by a non-contact laser flowmeter. 2-CN-Ado-induced increase in ocular blood flow was accompanied with the retinal vasodilation. The increase in ocular blood flow was inhibited by an adenosine A(2A) receptor antagonist 1,3,7-trimethyl-8-(3-chlorostyryl)xanthine, but not by an adenosine A(2B) receptor antagonist alloxazine or an adenosine A(1) receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine. The repetitive applications of topical 2-CN-Ado twice a day for 7 days produced a persistent increase in ocular blood flow with ocular hypotension. These results suggest that 2-CN-Ado increases the ocular blood flow mainly via adenosine A(2A) receptor, and that the topical application of 2-CN-Ado for several days not only increases the ocular blood flow but also prolong ocular hypotension, indicating that 2-CN-Ado may be a useful lead compound for the treatment of ischemic retinal diseases such as glaucoma. PMID:17239401

  4. An enzyme-free strategy for ultrasensitive detection of adenosine using a multipurpose aptamer probe and malachite green.

    Science.gov (United States)

    Zhao, Hui; Wang, Yong-Sheng; Tang, Xian; Zhou, Bin; Xue, Jin-Hua; Liu, Hui; Liu, Shan-Du; Cao, Jin-Xiu; Li, Ming-Hui; Chen, Si-Han

    2015-08-01

    We report on an enzyme-free and label-free strategy for the ultrasensitive determination of adenosine. A novel multipurpose adenosine aptamer (MAAP) is designed, which serves as an effective target recognition probe and a capture probe for malachite green. In the presence of adenosine, the conformation of the MAAP is converted from a hairpin structure to a G-quadruplex. Upon addition of malachite green into this solution, a noticeable enhancement of resonance light scattering was observed. The signal response is directly proportional to the concentration of adenosine ranging from 75 pM to 2.2 nM with a detection limit of 23 pM, which was 100-10,000 folds lower than those obtained by previous reported methods. Moreover, this strategy has been applied successfully for detecting adenosine in human urine and blood samples, further proving its reliability. The mechanism of adenosine inducing MAAP to form a G-quadruplex was demonstrated by a series of control experiments. Such a MAAP probe can also be used to other strategies such as fluorescence or spectrophotometric ones. We suppose that this strategy can be expanded to develop a universal analytical platform for various target molecules in the biomedical field and clinical diagnosis.

  5. A3 Adenosine Receptors Modulate Hypoxia-inducible Factor-1a Expression in Human A375 Melanoma Cells

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    Stefania Merighi

    2005-10-01

    Full Text Available Hypoxia-inducible factor-1 (HIF-1 is a key regulator of genes crucial to many aspects of cancer biology. The purine nucleoside, adenosine, accumulates within many tissues under hypoxic conditions, including that of tumors. Because the levels of both HIF-1 and adenosine are elevated within the hypoxic environment of solid tumors, we investigated whether adenosine may regulate HIF-1. Here we show that, under hypoxic conditions (< 2% 02, adenosine upregulates HIF-1α protein expression in a dose-dependent and timedependent manner, exclusively through the A3 receptor subtype. The response to adenosine was generated at the cell surface because the inhibition of A3 receptor expression, by using small interfering RNA, abolished nucleoside effects. A3 receptor stimulation in hypoxia also increases angiopoietin-2 (Ang-2 protein accumulation through the induction of HIF-1α. In particular, we found that A3 receptor stimulation activates p44/p42 and p38 mitogen-activated protein kinases, which are required for A3-induced increase of HIF-1a and Ang-2. Collectively, these results suggest a cooperation between hypoxic and adenosine signals that ultimately may lead to the increase in HIF-1-mediated effects in cancer cells.

  6. Cordycepin Increases Nonrapid Eye Movement Sleep via Adenosine Receptors in Rats

    Directory of Open Access Journals (Sweden)

    Zhenzhen Hu

    2013-01-01

    Full Text Available Cordycepin (3′-deoxyadenosine is a naturally occurring adenosine analogue and one of the bioactive constituents isolated from Cordyceps militaris/Cordyceps sinensis, species of the fungal genus Cordyceps. It has traditionally been a prized Chinese folk medicine for the human well-being. Because of similarity of chemical structure of adenosine, cordycepin has been focused on the diverse effects of the central nervous systems (CNSs, like sleep regulation. Therefore, this study was undertaken to know whether cordycepin increases the natural sleep in rats, and its effect is mediated by adenosine receptors (ARs. Sleep was recorded using electroencephalogram (EEG for 4 hours after oral administration of cordycepin in rats. Sleep architecture and EEG power spectra were analyzed. Cordycepin reduced sleep-wake cycles and increased nonrapid eye movement (NREM sleep. Interestingly, cordycepin increased θ (theta waves power density during NREM sleep. In addition, the protein levels of AR subtypes (A1, A2A, and A2B were increased after the administration of cordycepin, especially in the rat hypothalamus which plays an important role in sleep regulation. Therefore, we suggest that cordycepin increases theta waves power density during NREM sleep via nonspecific AR in rats. In addition, this experiment can provide basic evidence that cordycepin may be helpful for sleep-disturbed subjects.

  7. Voltammetric determination of adenosine and guanosine using fullerene-C(60)-modified glassy carbon electrode.

    Science.gov (United States)

    Goyal, Rajendra N; Gupta, Vinod K; Oyama, Munetaka; Bachheti, Neeta

    2007-02-28

    A fullerene-C(60)-modified glassy carbon electrode (GCE) is used for the simultaneous determination of adenosine and guanosine by differential pulse voltammetry. Compared to a bare glassy carbon electrode, the modified electrode exhibits an apparent shift of the oxidation potentials in the cathodic direction and a marked enhancement in the voltammetric peak current response for both the biomolecules. Linear calibration curves are obtained over the concentration range 0.5muM-1.0mM in 0.1M phosphate buffer solution at pH 7.2 with a detection limit of 3.02x10(-7)M and 1.45x10(-7)M for individual determination of adenosine and guanosine, respectively. The interference studies showed that the fullerene-C(60)-modified glassy carbon electrode exhibited excellent selectivity in the presence of hypoxanthine, xanthine, uric acid and ascorbic acid. The proposed procedure was successfully applied to detect adenosine and guanosine in human blood plasma and urine, without any preliminary pre-treatment. PMID:19071420

  8. Effect of caffeine and adenosine on G2 repair: mitotic delay and chromosome damage.

    Science.gov (United States)

    González-Fernández, A; Hernández, P; López-Sáez, J F

    1985-04-01

    Proliferating plant cells treated during the late S period with 5-aminouracil (AU), give the typical response that DNA-damaging agents induce, characterized by: an important mitotic delay, and a potentiation of the chromosome damage by caffeine post-treatment. The study of labelled prophases, after a tritiated thymidine pulse, allowed evaluation of the mitotic delay induced by AU as well as its reversion by caffeine, while chromosome damage was estimated by the percentage of anaphases and telophases showing chromosomal aberrations. Post-treatment with adenosine alone has shown no effect on mitotic delay or chromosomal damage. However, when cells after AU were incubated in caffeine plus adenosine, the chromosome damage potentiation was abolished without affecting the caffeine action on mitotic delay. As a consequence, we postulate that caffeine could have two effects on G2 cells with damaged DNA: the first, to cancel their mitotic delay and the second to inhibit some DNA-repair pathway(s). Only this last effect could be reversed by adenosine.

  9. GIRK channel activation via adenosine or muscarinic receptors has similar effects on rat atrial electrophysiology.

    Science.gov (United States)

    Wang, Xiaodong; Liang, Bo; Skibsbye, Lasse; Olesen, Søren-Peter; Grunnet, Morten; Jespersen, Thomas

    2013-08-01

    G protein-coupled inwardly rectifying K⁺ channels (GIRK) are important in the regulation of heart rate and atrial electrophysiology. GIRK channels are activated by G protein-coupled receptors, including muscarinic M₂ receptors and adenosine A₁ receptors. The aim of this study was to characterize and compare the electrophysiological effects of acetylcholine (ACh) and adenosine on GIRK channels in rat atria. Action potential duration at 90% repolarization (APD₉₀), effective refractory period (ERP), and resting membrane potential (RMP) were investigated in isolated rat atria by intracellular recordings. Both the adenosine analog N6-cyclopentyladenosine (CPA) and ACh profoundly shortened APD₉₀ and ERP and hyperpolarized the RMP. No additive or synergistic effect of CPA and ACh coapplication was observed. To antagonize GIRK channel activation, the specific inhibitor rTertiapin Q (TTQ) was applied. The coapplication of TTQ reversed the CPA and ACh-induced effects. When TTQ was applied without exogenous receptor activator, both APD₉₀ and ERP were prolonged and RMP was depolarized, confirming a basal activity of the GIRK current. The results reveal that activation of A₁ and M₂ receptors has a profound and equal effect on the electrophysiology in rat atrium. This effect is to a major extent mediated through GIRK channels. Furthermore, these results support the notion that atrial GIRK currents from healthy hearts have a basal component and additional activation can be mediated via at least 2 different receptor mechanisms. PMID:23609329

  10. 2-Aminopyrimidines as dual adenosine A1/A2A antagonists.

    Science.gov (United States)

    Robinson, Sarel J; Petzer, Jacobus P; Terre'Blanche, Gisella; Petzer, Anél; van der Walt, Mietha M; Bergh, Jacobus J; Lourens, Anna C U

    2015-11-01

    In this study thirteen 2-aminopyrimidine derivatives were synthesised and screened as potential antagonists of adenosine A1 and A2A receptors in order to further investigate the structure activity relationships of this class of compounds. 4-(5-Methylfuran-2-yl)-6-[3-(piperidine-1-carbonyl)phenyl]pyrimidin-2-amine (8m) was identified as a compound with high affinities for both receptors, with an A2AKi value of 6.34 nM and an A1Ki value of 9.54 nM. The effect of selected compounds on the viability of cultured cells was assessed and preliminary results indicate low cytotoxicity. In vivo efficacy at A2A receptors was illustrated for compounds 8k and 8m since these compounds attenuated haloperidol-induced catalepsy in rats. A molecular docking study revealed that the interactions between the synthesised compounds and the adenosine A2A binding site most likely involve Phe168 and Asn253, interactions which are similar for structurally related adenosine A2A receptor antagonists. PMID:26462195

  11. Structural and functional insights into DR2231 protein, the MazG-like nucleoside triphosphate pyrophosphohydrolase from Deinococcus radiodurans.

    Science.gov (United States)

    Gonçalves, Ana Maria D; de Sanctis, Daniele; McSweeney, Sean M

    2011-09-01

    Deinococcus radiodurans is among the very few bacterial species extremely resistant to ionizing radiation, UV light, oxidizing agents, and cycles of prolonged desiccation. The proteome of D. radiodurans reflects the evolutionary pressure exerted by chronic exposure to (nonradioactive) forms of DNA and protein damage. A clear example of this adaptation is the overrepresentation of protein families involved in the removal of non-canonical nucleoside triphosphates (NTPs) whose incorporation into nascent DNA would promote mutagenesis and DNA damage. The three-dimensional structure of the DR2231 protein has been solved at 1.80 Å resolution. This protein had been classified as an all-α-helical MazG-like protein. The present study confirms that it holds the basic structural module characteristic of the MazG superfamily; two helices form a rigid domain, and two helices form a mobile domain and connecting loops. Contrary to what is known of MazG proteins, DR2231 protein shows a functional affinity with dUTPases. Enzymatic and isothermal calorimetry assays have demonstrated high specificity toward dUTP but an inability to hydrolyze dTTP, a typical feature of dUTPases. Co-crystallization with the product of hydrolysis, dUMP, in the presence of magnesium or manganese cations, suggests similarities with the dUTP/dUDP hydrolysis mechanism reported for dimeric dUTPases. The genome of D. radiodurans encodes for all enzymes required for dTTP synthesis from dCMP, thus bypassing the need of a dUTPase. We postulate that DR2231 protein is not essential to D. radiodurans and rather performs "house-cleaning" functions within the framework of oxidative stress response. We further propose DR2231 protein as an evolutionary precursor of dimeric dUTPases.

  12. Analysis of the Endogenous Deoxynucleoside Triphosphate Pool in HIV-Positive and -Negative Individuals Receiving Tenofovir-Emtricitabine.

    Science.gov (United States)

    Chen, Xinhui; Castillo-Mancilla, Jose R; Seifert, Sharon M; McAllister, Kevin B; Zheng, Jia-Hua; Bushman, Lane R; MaWhinney, Samantha; Anderson, Peter L

    2016-09-01

    Tenofovir (TFV) disoproxil fumarate (TDF) and emtricitabine (FTC), two nucleos(t)ide analogs (NA), are coformulated as an anti-HIV combination tablet for treatment and preexposure prophylaxis (PrEP). TDF/FTC may have effects on the deoxynucleoside triphosphate (dNTP) pool due to their similar structures and similar metabolic pathways. We carried out a comprehensive clinical study to characterize the effects of TDF/FTC on the endogenous dNTP pool, from baseline to 30 days of TDF/FTC therapy, in both treatment-naive HIV-positive and HIV-negative individuals. dATP, dCTP, dGTP, and TTP were quantified in peripheral blood mononuclear cells (PBMC) with a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) methodology. Forty individuals (19 HIV-positive) were enrolled and underwent a baseline visit and then received TDF/FTC for at least 30 days. Longitudinal measurements were analyzed using mixed-model segmented linear regression analysis. The dNTPs were reduced by 14% to 37% relative to the baseline level within 3 days in both HIV-negative and HIV-positive individuals (P ≤ 0.003). These reductions persisted to various degrees at day 30. These findings indicate that dNTP pools are influenced by TDF/FTC therapy. This may alter cellular homeostasis and could increase the antiviral effect through a more favorable analog/dNTP ratio. Further work is needed to elucidate mechanisms, to evaluate the clinical significance of these findings, and to further probe differences between HIV-negative and HIV-positive individuals. (This study has been registered at ClinicalTrials.gov under identifier NCT01040091.). PMID:27353267

  13. Magnetic nanoformulation of azidothymidine 5’-triphosphate for targeted delivery across the blood–brain barrier

    Directory of Open Access Journals (Sweden)

    Zainulabedin M Saiyed

    2010-03-01

    Full Text Available Zainulabedin M Saiyed, Nimisha H Gandhi, Madhavan PN Nair1Department of Immunology, College of Medicine, Florida International University, Miami, FL, USAAbstract: Despite significant advances in highly active antiretroviral therapy (HAART, the prevalence of neuroAIDS remains high. This is mainly attributed to inability of antiretroviral therapy (ART to cross the blood–brain barrier (BBB, thus resulting in insufficient drug concentration within the brain. Therefore, development of an active drug targeting system is an attractive strategy to increase the efficacy and delivery of ART to the brain. We report herein development of magnetic azidothymidine 5’-triphosphate (AZTTP liposomal nanoformulation and its ability to transmigrate across an in vitro BBB model by application of an external magnetic field. We hypothesize that this magnetically guided nanoformulation can transverse the BBB by direct transport or via monocyte-mediated transport. Magnetic AZTTP liposomes were prepared using a mixture of phosphatidyl choline and cholesterol. The average size of prepared liposomes was about 150 nm with maximum drug and magnetite loading efficiency of 54.5% and 45.3%, respectively. Further, magnetic AZTTP liposomes were checked for transmigration across an in vitro BBB model using direct or monocyte-mediated transport by application of an external magnetic field. The results show that apparent permeability of magnetic AZTTP liposomes was 3-fold higher than free AZTTP. Also, the magnetic AZTTP liposomes were efficiently taken up by monocytes and these magnetic monocytes showed enhanced transendothelial migration compared to normal/non-magnetic monocytes in presence of an external magnetic field. Thus, we anticipate that the developed magnetic nanoformulation can be used for targeting active nucleotide analog reverse transcriptase inhibitors to the brain by application of an external magnetic force and thereby eliminate the brain HIV reservoir and help

  14. Inhibition of DNA replication, DNA repair synthesis, and DNA polymerases α and δ by butylphenyl deoxyguanosine triphosphate

    International Nuclear Information System (INIS)

    Semiconservative DNA replication in growing mammalian cells and ultraviolet (UV)-induced DNA repair synthesis in nongrowing mammalian cells are mediated by one or both of the aphidicolin-sensitive DNA polymerases, α and/or δ. They have studied the inhibition of replication and repair synthesis in permeable human cells by N2 (p-n-butylphenyl)-2'-deoxyguanosine-5'-triphosphate (BuPh dGTP), an agent which inhibits polymerase α strongly and polymerase δ weakly. Both processes are inhibited by BuPh-dGTP in competition with dGTP. The K/sub i/'s are, for replication, 2-3 μM and, for repair synthesis, 3-4 μM, consistent with the involvement of the same DNA polymerase in both processes. Inhibition of isolated human polymerase α by BuPh-dGTP is also competitive with dGTP, but the K/sub i/ is approximately 10 nM, several hundred-fold lower than the K/sub i/'s of replication and repair synthesis. Isolated polymerase δ is inhibited by BuPh-dGTP at doses similar to those which inhibit replication and repair synthesis, however, attempts to determine the K/sub i/ of polymerase δ were hampered by the finding that the dependence of δ activity on deoxyribunucleotide concentration is parabolic at low doses. This behavior differs from the behavior of polymerase α and of cellular DNA replication and repair synthesis, all of which show a simple, hyperbolic relationship between activity and deoxyribonucleotide concentration. Thus, inhibition of DNA replication and UV induced DNA repair synthesis by BuPh dGTP is quantitatively similar to DNA polymerase δ, but some other characteristics of the cellular processes are more similar to those of polymerase α

  15. Role of adipokinetic hormone and adenosine in the anti-stress response in Drosophila melanogaster.

    Science.gov (United States)

    Zemanová, Milada; Stašková, Tereza; Kodrík, Dalibor

    2016-01-01

    The role of adipokinetic hormone (AKH) and adenosine in the anti-stress response was studied in Drosophila melanogaster larvae and adults carrying a mutation in the Akh gene (Akh(1)), the adenosine receptor gene (AdoR(1)), or in both of these genes (Akh(1) AdoR(1) double mutant). Stress was induced by starvation or by the addition of an oxidative stressor paraquat (PQ) to food. Mortality tests revealed that the Akh(1) mutant was the most resistant to starvation, while the AdoR(1) mutant was the most sensitive. Conversely, the Akh(1) AdoR(1) double mutant was more sensitive to PQ toxicity than either of the single mutants. Administration of PQ significantly increased the Drome-AKH level in w(1118) and AdoR(1) larvae; however, this was not accompanied by a simultaneous increase in Akh gene expression. In contrast, PQ significantly increased the expression of the glutathione S-transferase D1 (GstD1) gene. The presence of both a functional adenosine receptor and AKH seem to be important for the proper control of GstD1 gene expression under oxidative stress, however, the latter appears to play more dominant role. On the other hand, differences in glutathione S-transferase (GST) activity among the strains, and between untreated and PQ-treated groups were minimal. In addition, the glutathione level was significantly lower in all untreated AKH- or AdoR-deficient mutant flies as compared with the untreated control w(1118) flies and further declined following treatment with PQ. All oxidative stress characteristics modified by mutations in Akh gene were restored or even improved by 'rescue' mutation in flies which ectopically express Akh. Thus, the results of the present study demonstrate the important roles of AKH and adenosine in the anti-stress response elicited by PQ in a D. melanogaster model, and provide the first evidence for the involvement of adenosine in the anti-oxidative stress response in insects. PMID:27374982

  16. Caffeine acts via A1 adenosine receptors to disrupt embryonic cardiac function.

    Directory of Open Access Journals (Sweden)

    Daniela L Buscariollo

    Full Text Available BACKGROUND: Evidence suggests that adenosine acts via cardiac A1 adenosine receptors (A1ARs to protect embryos against hypoxia. During embryogenesis, A1ARs are the dominant regulator of heart rate, and A1AR activation reduces heart rate. Adenosine action is inhibited by caffeine, which is widely consumed during pregnancy. In this study, we tested the hypothesis that caffeine influences developing embryos by altering cardiac function. METHODOLOGY/PRINCIPAL FINDINGS: Effects of caffeine and adenosine receptor-selective antagonists on heart rate were studied in vitro using whole murine embryos at E9.5 and isolated hearts at E12.5. Embryos were examined in room air (21% O(2 or hypoxic (2% O(2 conditions. Hypoxia decreased heart rates of E9.5 embryos by 15.8% and in E12.5 isolated hearts by 27.1%. In room air, caffeine (200 µM had no effect on E9.5 heart rates; however, caffeine increased heart rates at E12.5 by 37.7%. Caffeine abolished hypoxia-mediated bradycardia at E9.5 and blunted hypoxia-mediated bradycardia at E12.5. Real-time PCR analysis of RNA from isolated E9.5 and E12.5 hearts showed that A1AR and A2aAR genes were expressed at both ages. Treatment with adenosine receptor-selective antagonists revealed that SCH-58261 (A2aAR-specific antagonist had no affects on heart function, whereas DPCPX (A1AR-specific antagonist had effects similar to caffeine treatment at E9.5 and E12.5. At E12.5, embryonic hearts lacking A1AR expression (A1AR-/- had elevated heart rates compared to A1AR+/- littermates, A1AR-/- heart rates failed to decrease to levels comparable to those of controls. Caffeine did not significantly affect heart rates of A1AR-/- embryos. CONCLUSIONS/SIGNIFICANCE: These data show that caffeine alters embryonic cardiac function and disrupts the normal cardiac response to hypoxia through blockade of A1AR action. Our results raise concern for caffeine exposure during embryogenesis, particularly in pregnancies with increased risk of

  17. Pharmacological prevention of reperfusion injury in acute myocardial infarction. A potential role for adenosine as a therapeutic agent.

    Science.gov (United States)

    Quintana, Miguel; Kahan, Thomas; Hjemdahl, Paul

    2004-01-01

    The concept of reperfusion injury, although first recognized from animal studies, is now recognized as a clinical phenomenon that may result in microvascular damage, no-reflow phenomenon, myocardial stunning, myocardial hibernation and ischemic preconditioning. The final consequence of this event is left ventricular (LV) systolic dysfunction leading to increased morbidity and mortality. The typical clinical case of reperfusion injury occurs in acute myocardial infarction (MI) with ST segment elevation in which an occlusion of a major epicardial coronary artery is followed by recanalization of the artery. This may occur either spontaneously or by means of thrombolysis and/or by primary percutaneous coronary intervention (PCI) with efficient platelet inhibition by aspirin (acetylsalicylic acid), clopidogrel and glycoprotein IIb/IIIa inhibitors. Although the pathophysiology of reperfusion injury is complex, the major role that neutrophils play in this process is well known. Neutrophils generate free radicals, degranulation products, arachidonic acid metabolites and platelet-activating factors that interact with endothelial cells, inducing endothelial injury and neutralization of nitrous oxide vasodilator capacity. Adenosine, through its multi-targeted pharmacological actions, is able to inhibit some of the above-mentioned detrimental effects. The net protective of adenosine in in vivo models of reperfusion injury is the reduction of the infarct size, the improvement of the regional myocardial blood flow and of the regional function of the ischemic area. Additionally, adenosine preserves the post-ischemic coronary flow reserve, coronary blood flow and the post-ischemic regional contractility. In small-scale studies in patients with acute MI, treatment with adenosine has been associated with smaller infarcts, less no-reflow phenomenon and improved LV function. During elective PCI adenosine reduced ST segment shifts, lactate production and ischemic symptoms. During the

  18. Pooled comparison of regadenoson versus adenosine for measuring fractional flow reserve and coronary flow in the catheterization laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Stolker, Joshua M., E-mail: jstolker@yahoo.com [Mercy Heart and Vascular, 901 Patients First Drive, Washington, MO 63090 (United States); Saint Louis University, 3635 Vista Ave, St. Louis, MO 63110 (United States); Lim, Michael J., E-mail: limmj@slu.edu [Saint Louis University, 3635 Vista Ave, St. Louis, MO 63110 (United States); Shavelle, David M., E-mail: david.shavelle@med.usc.edu [University of Southern California, 1510 San Pablo St, Suite 322, Los Angeles, CA 90033 (United States); Morris, D. Lynn, E-mail: morrisdl@einstein.edu [Albert Einstein Medical Center, 5501 Old York Rd, Philadelphia, PA 19141 (United States); Angiolillo, Dominick J., E-mail: dominick.angiolillo@jax.ufl.edu [University of Florida Health-Jacksonville, 655 West 8th St, Jacksonville, FL 32209 (United States); Guzman, Luis A., E-mail: luis.guzman@jax.ufl.edu [University of Florida Health-Jacksonville, 655 West 8th St, Jacksonville, FL 32209 (United States); Kennedy, Kevin F., E-mail: kfkennedy@saint-lukes.org [Saint Luke' s Mid America Heart Institute, 4401 Wornall Road, Kansas City, MO 64111 (United States); Weber, Elizabeth, E-mail: eweber1@slu.edu [Saint Louis University, 3635 Vista Ave, St. Louis, MO 63110 (United States); Zareh, Meena, E-mail: meena.zareh@med.usc.edu [University of Southern California, 1510 San Pablo St, Suite 322, Los Angeles, CA 90033 (United States); Neumayr, Robert H., E-mail: robneumayr@gmail.com [Mercy Heart and Vascular, 901 Patients First Drive, Washington, MO 63090 (United States); Saint Louis University, 3635 Vista Ave, St. Louis, MO 63110 (United States); Zenni, Martin M., E-mail: martin.zenni@jax.ufl.edu [University of Florida Health-Jacksonville, 655 West 8th St, Jacksonville, FL 32209 (United States)

    2015-07-15

    Background: Adenosine is the gold standard for augmenting coronary flow during fractional flow reserve (FFR) testing of intermediate coronary stenoses. However, intravenous infusion is time-consuming and intracoronary injection is subject to variability. Regadenoson is a newer adenosine alternative administered as a single intravenous bolus during nuclear stress testing, but its efficacy and safety during FFR testing have been evaluated only in small, single-center studies. Methods: We pooled data from 5 academic hospitals, in which patients undergoing clinically-indicated FFR prospectively underwent comparison of intravenous adenosine infusion (140–175 mcg/kg/min) versus regadenoson bolus (400 mcg). Hemodynamics and symptoms with adenosine were recorded until maximal hyperemia occurred, and after returning to baseline hemodynamics, regadenoson was administered and monitoring was repeated. In a subset of patients with coronary flow data, average peak velocity (APV) at the distal flow sensor was recorded. Results: Of 149 patients enrolled, mean age was 59 ± 9 years, 76% were male, and 54% underwent testing of the left anterior descending artery. Mean adenosine-FFR and regadenoson-FFR were identical (0.82 ± 0.10) with excellent correlation of individual values (r = 0.96, p < 0.001) and no difference in patient-reported symptoms. Four patients (2.6%) had discrepancies between the 2 drugs for the clinical decision-making cutoff of FFR ≤ 0.80. Coronary flow responses to adenosine and regadenoson were similar (APV at maximal hyperemia 36 cm/s for both, p = 0.81). Conclusions: Regadenoson single-bolus administration has comparable FFR, symptoms, and coronary flow augmentation when compared with standard intravenous adenosine infusion. With its greater ease of administration, regadenoson may be a more “user-friendly” option for invasive ischemic testing.

  19. Effects of AMP579 and adenosine on L-type Ca2+ current in isolated rat ventricular myocytes

    Institute of Scientific and Technical Information of China (English)

    Xiong WANG; Bo-wei WU; Dong-mei WU

    2005-01-01

    Aim: To compare the effects of AMP579 and adenosine on L-type Ca2+ current (ICa- L) in rat ventricular myocytes and explore the mechanism by which AMP579 acts on ICa-L. Methods: ICa-L was recorded by patch-clamp technique in whole-cell configuration. Results: Adenosine (10 nmol/L to 50 μmol/L) showed no effect on basal ICa- L, but it inhibited the ICa-L induced by isoproterenol 10 nmol/L in a concen tration-dependent manner with the IC50 of 13.06 μmol/L. Similar to adenosine,AMP579 also showed an inhibitory effect on the ICa-L induced by isoproterenol.AMP579 and adenosine (both in 10 μmol/L) suppressed isoproterenol-induced ICa-L by 11.1% and 5.2%, respectively. In addition, AMP579 had a direct inhibitory effect on basal ICa-L in a concentration-dependent manner with IC50 (1.17 μmol/L).PD116948 (30 μmol/L), an adenosine A1 receptor blocker, showed no action on the inhibitory effect of AMP579 on basal ICa-L. However, GF109203X (0.4 μmol/L), a special protein kinase C (PKC) blocker, could abolish the inhibitory effect of AMP579 on basal ICa-L. So the inhibitory effect of AMP579 on basal ICa-L was induced through activating PKC, but not linked to adenosine A1 receptor. Conclusion:AMP579 shows a stronger inhibitory effect than adenosine on the ICa-L induced by isoproterenol. AMP579 also has a strong inhibitory effect on basal ICa-L in rat ventricular myocytes. Activation of PKC is involved in the inhibitory effect of AMP579 on basal ICa-L at downstream-mechanism.

  20. Pooled comparison of regadenoson versus adenosine for measuring fractional flow reserve and coronary flow in the catheterization laboratory

    International Nuclear Information System (INIS)

    Background: Adenosine is the gold standard for augmenting coronary flow during fractional flow reserve (FFR) testing of intermediate coronary stenoses. However, intravenous infusion is time-consuming and intracoronary injection is subject to variability. Regadenoson is a newer adenosine alternative administered as a single intravenous bolus during nuclear stress testing, but its efficacy and safety during FFR testing have been evaluated only in small, single-center studies. Methods: We pooled data from 5 academic hospitals, in which patients undergoing clinically-indicated FFR prospectively underwent comparison of intravenous adenosine infusion (140–175 mcg/kg/min) versus regadenoson bolus (400 mcg). Hemodynamics and symptoms with adenosine were recorded until maximal hyperemia occurred, and after returning to baseline hemodynamics, regadenoson was administered and monitoring was repeated. In a subset of patients with coronary flow data, average peak velocity (APV) at the distal flow sensor was recorded. Results: Of 149 patients enrolled, mean age was 59 ± 9 years, 76% were male, and 54% underwent testing of the left anterior descending artery. Mean adenosine-FFR and regadenoson-FFR were identical (0.82 ± 0.10) with excellent correlation of individual values (r = 0.96, p < 0.001) and no difference in patient-reported symptoms. Four patients (2.6%) had discrepancies between the 2 drugs for the clinical decision-making cutoff of FFR ≤ 0.80. Coronary flow responses to adenosine and regadenoson were similar (APV at maximal hyperemia 36 cm/s for both, p = 0.81). Conclusions: Regadenoson single-bolus administration has comparable FFR, symptoms, and coronary flow augmentation when compared with standard intravenous adenosine infusion. With its greater ease of administration, regadenoson may be a more “user-friendly” option for invasive ischemic testing

  1. The effect of eplerenone on adenosine formation in humans in vivo: a double-blinded randomised controlled study.

    Directory of Open Access Journals (Sweden)

    T N A van den Berg

    Full Text Available It has been suggested that mineralocorticoid receptor antagonists have direct cardioprotective properties, because these drugs reduce mortality in patients with heart failure. In murine models of myocardial infarction, mineralocorticoid receptor antagonists reduce infarct size. Using gene deletion and pharmacological approaches, it has been shown that extracellular formation of the endogenous nucleoside adenosine is crucial for this protective effect. We now aim to translate this finding to humans, by investigating the effects of the selective mineralocorticoid receptor antagonist eplerenone on the vasodilator effect of the adenosine uptake inhibitor dipyridamole, which is a well-validated surrogate marker for extracellular adenosine formation.In a randomised, double-blinded, placebo-controlled, cross-over study we measured the forearm blood flow response to the intrabrachial administration of dipyridamole in 14 healthy male subjects before and after treatment with placebo or eplerenone (50 mg bid for 8 days. The forearm blood flow during administration of dipyridamole (10, 30 and 100 µg·min(-1·dl(-1 was 1.63 (0.60, 2.13 (1.51 and 2.71 (1.32 ml·dl(-1·min(-1 during placebo use, versus 2.00 (1.45, 2.68 (1.87 and 3.22 (1.94 ml·dl(-1·min(-1 during eplerenone treatment (median (interquartile range; P = 0.51. Concomitant administration of the adenosine receptor antagonist caffeine attenuated dipyridamole-induced vasodilation to a similar extent in both groups. The forearm blood flow response to forearm ischemia, as a stimulus for increased formation of adenosine, was similar during both conditions.In a dosage of 50 mg bid, eplerenone does not augment extracellular adenosine formation in healthy human subjects. Therefore, it is unlikely that an increased extracellular adenosine formation contributes to the cardioprotective effect of mineralocorticoid receptor antagonists.ClinicalTrials.gov, NCT01837108.

  2. The comparison of two gated SPET protocols: adenosine Tc-99m tetrafosmin and treadmill exercise Tc-99m MIBI

    International Nuclear Information System (INIS)

    The effect of adenosine and exercise on gated SPET left ventricular ejection fraction (LVEF), end diastolic volume (EDV) and end systolic volume (ESV) has not been fully investigated. The aim of the study was to compare functional measurements obtained in one-day adenosine rest and two-day stress-rest protocols in relation to ischaemia. Out of 226 consecutive patients examined with submaximal treadmill stress-rest 700 MBq Tc-99m MIBI, 26 were chosen to match those subjected to adenosine (140 μg/kg/min) enhanced by a low level exercise protocol (300 MBq and 700 MBq Tc-99m tetrofosmin for stress and rest respectively). All images were acquired on a double head system and were gated using 8 frames, 25 s per frame. ED and ES volumes increased after adenosine but decreased after treadmill resulting in the post-stress LVEF being significantly greater than after adenosine, 60 ± 11 v. 51 ± 13% (p < 0.01). This was caused by the smaller post-stress ESV in the treadmill group 40 ± 20 v. 51 ± 34, p < 0.05. In non-ischaemic scans the LVEF was greater (61± 8 v. 51 ± 14, p < 0.01) and EDV and ESV smaller after both stress and rest. The adenosine test may have an opposite influence on the EDV and ESV in comparison to the submaximal treadmill test and therefore the left ventricular function measurements after adenosine infusion should be interpreted carefully and may not represent those acquired after physical exercise. In the gated SPET scans showing ischaemia the post-stress EDV and ESV may be greater and the LVEF lower than at rest. (author)

  3. Plasma concentrations of the cyclic nucleotides, adenosine 3',5'-monophosphate and guanosine 3'.5'-monophosphate, in healthy adults treated with theophylline

    DEFF Research Database (Denmark)

    Fenger, M; Eriksen, P B; Andersen, O;

    1982-01-01

    Plasma concentrations of cyclic adenosine monophosphate and cyclic guanosine monophosphate were measured in 10 health adults before, during and after periods of theophylline administration. Cyclic adenosine monophosphate concentrations did not change significantly, but cyclic guanosine monophosph......Plasma concentrations of cyclic adenosine monophosphate and cyclic guanosine monophosphate were measured in 10 health adults before, during and after periods of theophylline administration. Cyclic adenosine monophosphate concentrations did not change significantly, but cyclic guanosine...... monophosphate concentrations decreased by 29% on average when theophylline was administered. The change in cyclic guanosine monophosphate was not correlated to the plasma concentration of theophylline in the range studied....

  4. Sequencing, functional expression and characterization of rat NTPDase6, a nucleoside diphosphatase and novel member of the ecto-nucleoside triphosphate diphosphohydrolase family.

    Science.gov (United States)

    Braun, N; Fengler, S; Ebeling, C; Servos, J; Zimmermann, H

    2000-11-01

    We have isolated and characterized the cDNA encoding nucleoside triphosphate diphosphohydrolase 6 (NTPDase6), a novel member of the ecto-nucleoside triphosphate diphosphohydrolase family. The rat-brain-derived cDNA has an open reading frame of 1365 bp encoding a protein of 455 amino acid residues, a calculated molecular mass of 49971 Da and a predicted N-terminal hydrophobic sequence. It shares 86% sequence identity with the human CD39L2 sequence and 48% and 51% identity respectively with sequences of the two related human and murine nucleoside diphosphatases (CD39L4, NTPDase5/ER-UDPase). The mRNA was expressed in all tissues investigated, revealing two major transcripts with differing abundances. PCR analysis suggests a single open reading frame. A Myc-His-tagged NTPDase6 was expressed in Chinese hamster ovary (CHO) and PC12 cells for immunological analysis and protein isolation. The protein was contained in membrane fractions of transfected CHO cells and occurred in a soluble form in the cell culture supernatants. NTPDase6 preferentially hydrolysed nucleoside 5'-diphosphates. With different substrates the order of activity was GDP>IDP>UDP,CDP>ADP. Nucleoside 5'-triphosphates were hydrolysed only to a minor extent and no hydrolysis of nucleoside 5'-monophosphates was observed. The enzyme was strongly and equally activated by Ca(2+) and Mg(2+) and had a K(m) for GDP of 211 microM. The immunohistochemical analysis of transfected CHO and PC12 cells suggests that NTPDase6 is associated with the Golgi apparatus and to a small extent also with the plasma membrane. The enzyme might support glycosylation reactions in the Golgi apparatus and, when released from cells, might catalyse the hydrolysis of extracellular nucleotides. PMID:11042118

  5. Dihydrothymidine and thymidine glycol triphosphates as substrates for DNA polymerases: differential recognition of thymine C5-C6 bond saturation and sequence specificity of incorporation.

    OpenAIRE

    Ide, H; Wallace, S. S.

    1988-01-01

    The ability of dihydrothymidine (DHdTTP) and thymidine glycol (dTTP-GLY) 5'-triphosphates to serve as substrates for different DNA polymerases was investigated. DHdTTP but not dTTP-GLY was used as a substrate by E. coli DNA polymerase I (Pol I). Within the detection limit of the assay used, neither T4 DNA polymerase nor avian myeloblastosis virus (AMV) reverse transcriptase used DHdTTP or dTTP-GLY as substrates. The ability of DHdTTP and dTTP-GLY to undergo enzyme-catalyzed turnover to the mo...

  6. Comparison of Hemodynamic Effects and Negative Predictive Value of Normal Adenosine Gated Myocardial Perfusion Scan With or Without Caffeine Abstinence.

    Science.gov (United States)

    Uz Zaman, Maseeh; Fatima, Nosheen; Zaman, Areeba; Zaman, Unaiza; Tahseen, Rabia

    2016-09-01

    For vasodilator stress, myocardial perfusion imaging (MPI) with at least 12-h caffeine abstinence is recommended, as it attenuates cardiovascular hyperemic response of adenosine and dipyridamole. However, many published conflicting results have shown no significant effect upon perfusion abnormalities in MPI performed without caffeine abstinence. The aim of this study was to compare the hemodynamic changes and negative predictive value (NPV) of normal MPIs with adenosine stress performed with or without caffeine abstinence. This was a prospective study that accrued 50 patients from May 2013 till September 2013 and followed till November 2014. These patients had a normal adenosine-gated MPI (GMPI) with technetium-99m methoxy isobutyl isonitrile ((99m)Tc-MIBI) after 12-h caffeine abstinence (no-caffeine). Next day, all patients had a repeat adenosine stress within 60 min after ingestion of a cup of coffee (about 80 mg of caffeine) followed by no MPI in 30 patients due to concern about radiation dose (prior-caffeine adenosine-no MPI; group A). Twenty patients opted for a repeat MPI (prior-caffeine adenosine-MPI; group B). Adenosine-induced hemodynamic response and NPV of the normal MPI with no-caffeine and prior-caffeine protocols were compared. The mean age of the study cohort was 57 ± 9 years with a male-to-female ratio of 76:24% and mean body mass index (BMI) of 26.915 ± 4.121 kg/m(2). Prevalence of hypertension, diabetes, dyslipidemia, and positive family history were 76%, 20%, 22%, and 17%, respectively. Comparison of group A with group B revealed no significant difference in demographic parameters, hemodynamic or electrocardiography (ECG) parameters, or left ventricular (LV) function parameters during adenosine intervention with prior-caffeine and no-caffeine protocols. During the follow-up, no fatal myocardial infarction (MI) was reported but 6 nonfatal MIs were reported based upon the history of short hospitalization for chest pain but without biochemical or

  7. Extracellular Adenosine Protects against Streptococcus pneumoniae Lung Infection by Regulating Pulmonary Neutrophil Recruitment.

    Science.gov (United States)

    Bou Ghanem, Elsa N; Clark, Stacie; Roggensack, Sara E; McIver, Sally R; Alcaide, Pilar; Haydon, Philip G; Leong, John M

    2015-08-01

    An important determinant of disease following Streptococcus pneumoniae (pneumococcus) lung infection is pulmonary inflammation mediated by polymorphonuclear leukocytes (PMNs). We found that upon intratracheal challenge of mice, recruitment of PMNs into the lungs within the first 3 hours coincided with decreased pulmonary pneumococci, whereas large numbers of pulmonary PMNs beyond 12 hours correlated with a greater bacterial burden. Indeed, mice that survived infection largely resolved inflammation by 72 hours, and PMN depletion at peak infiltration, i.e. 18 hours post-infection, lowered bacterial numbers and enhanced survival. We investigated host signaling pathways that influence both pneumococcus clearance and pulmonary inflammation. Pharmacologic inhibition and/or genetic ablation of enzymes that generate extracellular adenosine (EAD) (e.g. the ectoenzyme CD73) or degrade EAD (e.g. adenosine deaminase) revealed that EAD dramatically increases murine resistance to S. pneumoniae lung infection. Moreover, adenosine diminished PMN movement across endothelial monolayers in vitro, and although inhibition or deficiency of CD73 had no discernible impact on PMN recruitment within the first 6 hours after intratracheal inoculation of mice, these measures enhanced PMN numbers in the pulmonary interstitium after 18 hours of infection, culminating in dramatically elevated numbers of pulmonary PMNs at three days post-infection. When assessed at this time point, CD73-/- mice displayed increased levels of cellular factors that promote leukocyte migration, such as CXCL2 chemokine in the murine lung, as well as CXCR2 and β-2 integrin on the surface of pulmonary PMNs. The enhanced pneumococcal susceptibility of CD73-/- mice was significantly reversed by PMN depletion following infection, suggesting that EAD-mediated resistance is largely mediated by its effects on PMNs. Finally, CD73-inhibition diminished the ability of PMNs to kill pneumococci in vitro, suggesting that EAD alters

  8. Cerebral A{sub 1} adenosine receptors (A{sub 1}AR) in liver cirrhosis

    Energy Technology Data Exchange (ETDEWEB)

    Boy, Christian [Research Centre Juelich, Brain Imaging Centre West, Institute of Medicine, Juelich (Germany); University Hospital Essen, Department of Nuclear Medicine, Essen (Germany); Meyer, Philipp T. [Research Centre Juelich, Brain Imaging Centre West, Institute of Medicine, Juelich (Germany); University Hospital Aachen, Department of Nuclear Medicine, Aachen (Germany); Kircheis, Gerald; Haussinger, Dieter [University of Duesseldorf, Clinic for Gastroenterology, Hepatology and Infectiology, Duesseldorf (Germany); Holschbach, Marcus H.; Coenen, Heinz H. [Research Centre Juelich, Institute of Nuclear Chemistry, Juelich (Germany); Herzog, Hans; Elmenhorst, David [Research Centre Juelich, Brain Imaging Centre West, Institute of Medicine, Juelich (Germany); Kaiser, Hans J. [University Hospital Aachen, Department of Nuclear Medicine, Aachen (Germany); Zilles, Karl [Research Centre Juelich, Brain Imaging Centre West, Institute of Medicine, Juelich (Germany); C. and O. Vogt Institute of Brain Research, Duesseldorf (Germany); Bauer, Andreas [Research Centre Juelich, Brain Imaging Centre West, Institute of Medicine, Juelich (Germany); University of Duesseldorf, Department of Neurology, Duesseldorf (Germany)

    2008-03-15

    The cerebral mechanisms underlying hepatic encephalopathy (HE) are poorly understood. Adenosine, a neuromodulator that pre- and postsynaptically modulates neuronal excitability and release of classical neurotransmitters via A{sub 1} adenosine receptors (A{sub 1}AR), is likely to be involved. The present study investigates changes of cerebral A{sub 1}AR binding in cirrhotic patients by means of positron emission tomography (PET) and [{sup 18}F]CPFPX, a novel selective A{sub 1}AR antagonist. PET was performed in cirrhotic patients (n = 10) and healthy volunteers (n = 10). Quantification of in vivo receptor density was done by Logan's non-invasive graphical analysis (pons as reference region). The outcome parameter was the apparent binding potential (aBP, proportional to B{sub max}/K{sub D}). Cortical and subcortical regions showed lower A{sub 1}AR binding in cirrhotic patients than in controls. The aBP changes reached statistical significance vs healthy controls (p < 0.05, U test with Bonferroni-Holm adjustment for multiple comparisons) in cingulate cortex (-50.0%), precentral gyrus (-40.9%), postcentral gyrus (-38.6%), insular cortex (-38.6%), thalamus (-32.9%), parietal cortex (-31.7%), frontal cortex (-28.6), lateral temporal cortex (-28.2%), orbitofrontal cortex (-27.9%), occipital cortex (-24.6), putamen (-22.7%) and mesial temporal lobe (-22.4%). Regional cerebral adenosinergic neuromodulation is heterogeneously altered in cirrhotic patients. The decrease of cerebral A{sub 1}AR binding may further aggravate neurotransmitter imbalance at the synaptic cleft in cirrhosis and hepatic encephalopathy. Different pathomechanisms may account for these alterations including decrease of A{sub 1}AR density or affinity, as well as blockade of the A{sub 1}AR by endogenous adenosine or exogenous xanthines. (orig.)

  9. Adenosine-induced coronary flow reserve in Watanabe heritable hyperlipidemic rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Shimada, Kazuhiro; Yoshida, Katsuya [Chiba Univ. (Japan). School of Medicine; Tadokoro, Hiroyuki [and others

    2000-12-01

    The Watanabe heritable hyperlipidemic (WHHL) rabbit develops coronary atherosclerosis and hypercholesterolemia because of a genetic deficiency of low-density lipoprotein receptors and is therefore a good animal model for studying the relationships of coronary atherosclerosis, hypercholesterolemia and coronary flow reserve. The aim of the present study was to assess myocardial perfusion at baseline and during adenosine infusion (0.2 mg{center_dot}kg{sup -1}{center_dot}min{sup -1}) in 8 WHHL rabbits (13.8{+-}0.5 months) with {sup 13}N-ammonia, small-animal positron emission tomography (PET) and colored microspheres. Results were compared with those from 6 age-matched Japanese white rabbits. Plaque distribution was also examined in the extramural coronary arteries. All 8 WHHL rabbits had coronary plaques, with 6 showing multiple plaques. Mean global myocardial blood flow (ml{center_dot}min{sup -1}{center_dot}g{sup -1}) did not differ significantly between control and WHHL groups both at baseline (3.67{+-}0.72 vs 4.26{+-}1.12 ml{center_dot}min{sup -1}{center_dot}g{sup -1}, p=NS) and with adenosine (7.92{+-}2.00 vs 9.27{+-}2.91 ml{center_dot}min{sup -1}{center_dot}g{sup -1}, p=NS), nor did coronary flow reserve (2.16{+-}0.37 vs 2.18{+-}0.41, p=NS). None showed evidence of regional perfusion abnormalities by visual and semiquantitative analyses of PET images. It was concluded that WHHL rabbits preserve adenosine-induced coronary flow reserve despite coronary atherosclerosis and hypercholesterolemia, suggesting that a compensatory mechanism develops in this animal model. (author)

  10. Adenosine-induced coronary flow reserve in Watanabe heritable hyperlipidemic rabbits

    International Nuclear Information System (INIS)

    The Watanabe heritable hyperlipidemic (WHHL) rabbit develops coronary atherosclerosis and hypercholesterolemia because of a genetic deficiency of low-density lipoprotein receptors and is therefore a good animal model for studying the relationships of coronary atherosclerosis, hypercholesterolemia and coronary flow reserve. The aim of the present study was to assess myocardial perfusion at baseline and during adenosine infusion (0.2 mg·kg-1·min-1) in 8 WHHL rabbits (13.8±0.5 months) with 13N-ammonia, small-animal positron emission tomography (PET) and colored microspheres. Results were compared with those from 6 age-matched Japanese white rabbits. Plaque distribution was also examined in the extramural coronary arteries. All 8 WHHL rabbits had coronary plaques, with 6 showing multiple plaques. Mean global myocardial blood flow (ml·min-1·g-1) did not differ significantly between control and WHHL groups both at baseline (3.67±0.72 vs 4.26±1.12 ml·min-1·g-1, p=NS) and with adenosine (7.92±2.00 vs 9.27±2.91 ml·min-1·g-1, p=NS), nor did coronary flow reserve (2.16±0.37 vs 2.18±0.41, p=NS). None showed evidence of regional perfusion abnormalities by visual and semiquantitative analyses of PET images. It was concluded that WHHL rabbits preserve adenosine-induced coronary flow reserve despite coronary atherosclerosis and hypercholesterolemia, suggesting that a compensatory mechanism develops in this animal model. (author)

  11. [Mast cells, their adenosine receptors and reactive oxygen species in chronic inflammatory pathologies of childhood].

    Science.gov (United States)

    Renke, Joanna; Popadiuk, Stefan; Wozniak, Michał; Szlagatys-Sidorkiewicz, Agnieszka; Hansdorfer-Korzon, Rita

    2006-01-01

    Mast cells were described by Erhlich at the end of XIX-th century. Their role was deeply investigated in asthma and allergy. The massive degranulation of mast cells in allergy can lead to anaphylactic shock. Recently, mast cells have been recognized again as a very interesting topic for investigation, due to their possible role in chronic inflammation. Moreover, through adenosine receptors, mast cells can be activated or inactivated. That is why these cells are regarded as a potential target of new drugs. It has been reported, that mast cells generate intracellular reactive oxygen species (ROS) in response to stimulation with divergent physiologically relevant stimulants. The intensification of ROS production may be measured by the level of carbonyl groups, as a marker of protein peroxidation. However, the role of mast cells in other than asthma diseases with chronic inflammation needs further investigation. It was found out that the information about mast cell distribution in colonic mucosa may serve as help in differentiation between inflammatory bowel disease and collagenous colitis. Moreover, its accumulation in focal active gastritis was confirmed in patients with Crohn's disease. An important role in regulation of inflammatory process seems to be reserved for adenosine receptors present on mastocytes. The activation of mast cells through the adenosine receptor is connected with 11-8 release, which stimulate the migration of leukocytes and oxidation reactions. The detection of mast cells in tissues should not be limited only to the simple histologic examination. It should be completed by the detection of products of degranulation, e.g. tryptase. This is the way to find out their actual function and state of activation. PMID:17203808

  12. Dyspnea and Wheezing after Adenosine Injection in a Patient with Eosinophilic Bronchitis

    Directory of Open Access Journals (Sweden)

    Rodrigo Cartin-Ceba

    2009-01-01

    Full Text Available A 58-year-old nonsmoker female was referred for evaluation of chronic cough of 13 months duration. After an initial work-up, the patient was diagnosed to have chronic cough due to eosinophilic bronchitis. The diagnostic work-up for eosinophilic bronchitis and bronchial biopsy is discussed. Eosinophilic bronchitis is differentiated from asthma. In addition, the patient developed dyspnea, flushing, and wheezing after the administration of adenosine during a cardiac stress test in spite of a negative methacholine challenge. This indirect stimulus of airway hyperresponsiveness suggests the possible involvement of mast cells in eosinophilic bronchitis.

  13. Stimulation of NTS A1 adenosine receptors differentially resets baroreflex control of regional sympathetic outputs.

    Science.gov (United States)

    Scislo, Tadeusz J; Ichinose, Tomoko K; O'Leary, Donal S

    2008-01-01

    Previously we showed that pressor and differential regional sympathoexcitatory responses (adrenal > renal >/= lumbar) evoked by stimulation of A(1) adenosine receptors located in the nucleus of the solitary tract (NTS) were attenuated/abolished by baroreceptor denervation or blockade of glutamatergic transmission in the NTS, suggesting A(1) receptor-elicited inhibition of glutamatergic transmission in baroreflex pathways. Therefore we tested the hypothesis that stimulation of NTS A(1) adenosine receptors differentially inhibits/resets baroreflex responses of preganglionic adrenal (pre-ASNA), renal (RSNA), and lumbar (LSNA) sympathetic nerve activity. In urethane-chloralose-anesthetized male Sprague-Dawley rats (n = 65) we compared baroreflex-response curves (iv nitroprusside and phenylephrine) evoked before and after bilateral microinjections into the NTS of A(1) adenosine receptor agonist (N(6)-cyclopentyladenosine, CPA; 0.033-330 pmol/50 nl). CPA evoked typical dose-dependent pressor and differential sympathoexcitatory responses and similarly shifted baroreflex curves for pre-ASNA, RSNA, and LSNA toward higher mean arterial pressure (MAP) in a dose-dependent manner; the maximal shifts were 52.6 +/- 2.8, 48.0 +/- 3.6, and 56.8 +/- 6.7 mmHg for pre-ASNA, RSNA, and LSNA, respectively. These shifts were not a result of simple baroreceptor resetting because they were two to three times greater than respective increases in baseline MAP evoked by CPA. Baroreflex curves for pre-ASNA were additionally shifted upward: the maximal increases of upper and lower plateaus were 41.8 +/- 16.4% and 45.3 +/- 8.7%, respectively. Maximal gain (%/mmHg) measured before vs. after CPA increased for pre-ASNA (3.0 +/- 0.6 vs. 4.9 +/- 1.3), decreased for RSNA (4.1 +/- 0.6 vs. 2.3 +/- 0.3), and remained unaltered for LSNA (2.1 +/- 0.2 vs. 2.0 +/- 0.1). Vehicle control did not alter the baroreflex curves. We conclude that the activation of NTS A(1) adenosine receptors differentially inhibits

  14. High-frequency Electrocardiogram Analysis in the Ability to Predict Reversible Perfusion Defects during Adenosine Myocardial Perfusion Imaging

    Science.gov (United States)

    Tragardh, Elin; Schlegel, Todd T.; Carlsson, Marcus; Pettersson, Jonas; Nilsson, Klas; Pahlm, Olle

    2007-01-01

    Background: A previous study has shown that analysis of high-frequency QRS components (HF-QRS) is highly sensitive and reasonably specific for detecting reversible perfusion defects on myocardial perfusion imaging (MPI) scans during adenosine. The purpose of the present study was to try to reproduce those findings. Methods: 12-lead high-resolution electrocardiogram recordings were obtained from 100 patients before (baseline) and during adenosine Tc-99m-tetrofosmin MPI tests. HF-QRS were analyzed regarding morphology and changes in root mean square (RMS) voltages from before the adenosine infusion to peak infusion. Results: The best area under the curve (AUC) was found in supine patients (AUC=0.736) in a combination of morphology and RMS changes. None of the measurements, however, were statistically better than tossing a coin (AUC=0.5). Conclusion: Analysis of HF-QRS was not significantly better than tossing a coin for determining reversible perfusion defects on MPI scans.

  15. Increased level of soluble adenosine deaminase in bone marrow of visceral leishmaniasis patients: an inverse relation with parasite load.

    Science.gov (United States)

    Rai, Ambak K; Kumar, Prabin; Saini, Sheetal; Thakur, Chandreshwar P; Seth, Tulika; Mitra, Dipendra K

    2016-09-01

    Adenosine deaminase (ADA) which degrades adenosine to inosine, is known to be pro-inflammatory molecule in many diseases. Adenosine suppresses the functioning of the immune system and thus promotes dissemination of the parasite. In our previous finding, the level of soluble ADA in serum of visceral leishmaniasis (VL) was found to be increased as compared to healthy controls. However, it cannot be fairly interpreted unless their level is demonstrated at the disease site, where the parasite resides. We designed this study to correlate the level of soluble ADA (sADA) with parasitic load at the disease site i.e. bone marrow (BM). We found increased levels of sADA in BM as compared to the unaffected BM. Furthermore, a significant inverse correlation is observed between the parasite load and level of sADA at the disease site. PMID:27447233

  16. Adenosine is required for sustained inflammasome activation via the A2A receptor and the HIF-1α pathway

    Science.gov (United States)

    Ouyang, Xinshou; Ghani, Ayaz; Malik, Ahsan; Wilder, Tuere; Colegio, Oscar Rene; Flavell, Richard Anthony; Cronstein, Bruce Neil; Mehal, Wajahat Zafar

    2013-12-01

    Inflammasome pathways are important in chronic diseases; however, it is not known how the signalling is sustained after initiation. Inflammasome activation is dependent on stimuli such as lipopolysaccharide (LPS) and ATP that provide two distinct signals resulting in rapid production of interleukin (IL)-1β, with the lack of response to repeat stimulation. Here we report that adenosine is a key regulator of inflammasome activity, increasing the duration of the inflammatory response via the A2A receptor. Adenosine does not replace signals provided by stimuli such as LPS or ATP but sustains inflammasome activity via a cAMP/PKA/CREB/HIF-1α pathway. In the setting of the lack of IL-1β responses after previous exposure to LPS, adenosine can supersede this tolerogenic state and drive IL-1β production. These data reveal that inflammasome activity is sustained, after initial activation, by A2A receptor-mediated signalling.

  17. Fluorometric determination of 2'-beta-fluoro-2',3'-dideoxyadenosine 5'-triphosphate, the active metabolite of a new anti-human immunodeficiency virus drug, in human lymphocytes.

    Science.gov (United States)

    Dai, F; Kelley, J A; Zhang, H; Malinowski, N; Kavlick, M F; Lietzau, J; Welles, L; Yarchoan, R; Ford, H

    2001-01-01

    A sensitive precolumn derivatization method has been developed to measure the 5'-triphosphate of 2'-beta-fluoro-2',3'-dideoxyadenosine (F-ddA, lodenosine), a new anti-HIV drug, in human lymphocytes by HPLC using fluorescence detection. Reaction of chloroacetaldehyde with F-ddA triphosphate in extracts from human lymphocytes produces a highly fluorescent etheno adduct. This derivative is then separated and quantitated by reverse-phase paired-ion chromatography. Degradation of natural nucleic acid ribosides, such as ATP, using periodate oxidation simplifies the chromatogram and minimizes interference with detection of the target analyte. This method, modeled using cultured MOLT-4 T-lymphocytes, achieves a linear detector response for peak area measurements over the range 2.5 to 22.5 pmol (50-450 nM using 50 microl sample). Analyte recovery is greater than 90%, and the method achieves a limit of detection and limit of quantitation of 1.4 and 2.5 pmol per HPLC injection (50 microl sample containing cellular extract from 2.5 x 10(6) cells), respectively. Application of this method to measure F-ddATP in peripheral blood mononuclear cells from HIV-infected patients treated with F-ddA at 3.2 mg/kg twice daily for 22 days shows F-ddATP levels which range from 1.5 to 3.5 pmol/10(6) cells. PMID:11141306

  18. Isolation of a gene encoding a developmentally regulated T cell-specific protein with a guanine nucleotide triphosphate-binding motif

    Energy Technology Data Exchange (ETDEWEB)

    Carlow, D.A.; Teh, H.S.; Marth, J. [Univ. of British Columbia, Vancouver (Canada)] [and others

    1995-02-15

    In this study, we describe a novel full length cDNA clone designated Tgtp that encodes a predicted 415-amino acid a T cell-specific guanine nucleotide triphosphate-binding protein (TGTP) bearing the characteristic motifs of a guanine nucleotide triphosphate (GTP) binding protein. Tgtp is expressed preferentially, if not exclusively, in T cells, and is up-regulated in both unfractionated and in purified CD4{sup +}8{sup +} thymocytes upon TCR cross-linking. In contrast, expression of Tgtp in peripheral T cells is maintained at relatively high levels and is not grossly affected by TCR cross-linking. Antiserum generated against synthetic peptides from the predicted TGTP amino acid sequence recognized a single protein with a molecular mass of {approx}50 kDa, corresponding well with the computed molecular mass of 47 kDa. The only known relative of Tgtp is MUSGTP, which is reportedly expressed in B cells and bears a GTP binding motif. Thus, the discovery of Tgtp resolves a subfamily of molecules with GTP binding motifs and apparent lymphoid lineage-restricted expression. Given the restricted expression pattern in T cells, the up-regulated expression observed in response to TCR signaling in immature thymocytes, and the presence of the motifs characteristic of GTP binding proteins, we suggest that TGTP may have an important function in T cell development and/or T cell activation. 51 refs., 6 figs.

  19. Pharmacogenetic research progress of inosine triphosphate pyrophosphatase%三磷酸肌苷焦磷酸酶药理遗传学的研究进展

    Institute of Scientific and Technical Information of China (English)

    李兴军

    2013-01-01

    嘌呤类药物主要用于治疗自身免疫性疾病、器官移植、急性淋巴细胞白血病等,其不良反应的发生率为15% ~28%,严重影响了药物在临床中的应用.三磷酸肌苷焦磷酸酶(inosine triphosphate pyrophosphatase,ITPA)存在个体间的差异,ITPA缺陷的患者在应用嘌呤类药物时会发生一定的不良反应,因此,有必要了解ITPA对嘌呤类药物临床应用的影响,该文综述了ⅡPA的药理遗传学方面的研究进展.%Purine drugs are for the treatment of autoimmune diseases,organ transplantation,acute lymphoblastic leukemia.The adverse reaction rate is 15% ~ 28%,which impacts on the clinical application in recent years.Studies have shown that inosine triphosphate pyrophosphatase (ITPA) are different between individuals,and there are adverse reactions in patients with defects of ITPA when purine drugs are used.This paper reviewes the ITPA pharmacogenetic research progresses.

  20. Regional differences in the electrically stimulated release of endogenous and radioactive adenosine and purine derivatives from rat brain slices.

    Science.gov (United States)

    Pedata, F; Pazzagli, M; Tilli, S; Pepeu, G

    1990-10-01

    The release of both radioactive and endogenous purines was investigated in rat brain cortical, hippocampal and striatal slices at rest and following stimulation with electrical fields. Purines were labelled by incubating the slices with 3H-adenine. The purine efflux at rest and that evoked by electrical stimulation (10 Hz. 5 min) was analyzed by HPLC with ultraviolet absorbance detection. Both radioactive and endogenous purines in the effluent consisted mainly of hypoxanthine, xanthine, inosine and adenosine. No qualitative differences in the composition of the released purines were found in the three areas investigated. Electrical stimulation evoked a net increase in both radioactive and endogenous purine release. However the increase in 3H-adenosine following electrical stimulation was twice as large as that of endogenous adenosine. The electrically evoked release of both radioactive and endogenous purines was greatest in hippocampal slices and progressively smaller in cortical and striatal slices. In the three areas the addition of 0.5 microM tetrodotoxin to the superfusing Krebs solution brought about a similar (83-100%) reduction in evoked 3H-purine and endogenous purine release. Superfusion of the slices with calcium-free Krebs solution containing 0.5 mM EGTA reduced evoked release of 3H-purines by 58-60% and that of endogenous purine components by 54-89%. The results demonstrate similar characteristics for both radioactive and endogenous purine release but indicate that the most recently synthetized adenosine is the most readily available for release. The features of the electrically evoked purine release support a neuronal origin of adenosine and derivatives and are consistent with the hypothesis of discrete regional differences in adenosine neuromodulation. PMID:2255336

  1. Stabilizing effects of G protein on the active conformation of adenosine A1 receptor differ depending on G protein type.

    Science.gov (United States)

    Tateyama, Michihiro; Kubo, Yoshihiro

    2016-10-01

    G protein coupled receptors (GPCRs) trigger various cellular and physiological responses upon the ligand binding. The ligand binding induces conformational change in GPCRs which allows G protein to interact with the receptor. The interaction of G protein also affects the active conformation of GPCRs. In this study, we have investigated the effects of Gαi1, Gαo and chimeric Gαqi5 on the active conformation of the adenosine A1 receptor, as each Gα showed difference in the interaction with adenosine A1 receptor. The conformational changes in the adenosine A1 receptor were detected as the agonist-induced decreases in efficiency of Förster resonance energy transfer (FRET) between fluorescent proteins (FPs) fused at the two intracellular domains of the adenosine A1 receptor. Amplitudes of the agonist-induced FRET decreases were subtle when the FP-tagged adenosine A1 receptor was expressed alone, whereas they were significantly enhanced when co-expressed with Gαi1Gβ1Gγ22 (Gi1) or Gαqi5Gβ1Gγ22 (Gqi5) but not with GαοGβ1Gγ22 (Go). The enhancement of the agonist-induced FRET decrease in the presence of Gqi5 was significantly larger than that of Gi1. Furthermore, the FRET recovery upon the agonist removal in the presence of Gqi5 was significantly slower than that of Gi1. From these results it was revealed that the agonist-bound active conformation of adenosine A1 receptor is unstable without the binding of G protein and that the stabilizing effects of G protein differ depending on the types of G protein.

  2. Interactions of adenosine, prostaglandins and nitric oxide in hypoxia-induced vasodilatation: in vivo and in vitro studies

    Science.gov (United States)

    Ray, Clare J; Abbas, Mark R; Coney, Andrew M; Marshall, Janice M

    2002-01-01

    Adenosine, prostaglandins (PG) and nitric oxide (NO) have all been implicated in hypoxia-evoked vasodilatation. We investigated whether their actions are interdependent. In anaesthetised rats, the PG synthesis inhibitors diclofenac or indomethacin reduced muscle vasodilatation evoked by systemic hypoxia or adenosine, but not that evoked by iloprost, a stable analogue of prostacyclin (PGI2), or by an NO donor. After diclofenac, the A1 receptor agonist CCPA evoked no vasodilatation: we previously showed that A1, but not A2A, receptors mediate the hypoxia-induced muscle vasodilatation. Further, in freshly excised rat aorta, adenosine evoked a release of NO, detected with an NO-sensitive electrode, that was abolished by NO synthesis inhibition, or endothelium removal, and reduced by ≈50 % by the A1 antagonist DPCPX, the remainder being attenuated by the A2A antagonist ZM241385. Diclofenac reduced adenosine-evoked NO release by ≈50 % under control conditions, abolished that evoked in the presence of ZM241385, but did not affect that evoked in the presence of DPCPX. Adenosine-evoked NO release was also abolished by the adenyl cyclase inhibitor 2′,5′-dideoxyadenosine, while dose-dependent NO release was evoked by iloprost. Finally, stimulation of A1, but not A2A, receptors caused a release of PGI2 from rat aorta, assessed by radioimmunoassay of its stable metabolite, 6-keto PGF1α, that was abolished by diclofenac. These results suggest that during systemic hypoxia, adenosine acts on endothelial A1 receptors to increase PG synthesis, thereby generating cAMP, which increases the synthesis and release of NO and causes muscle vasodilatation. This pathway may be important in other situations involving these autocoids. PMID:12356892

  3. Granulocyte colony-stimulating factor and drugs elevating extracellular adenosine synergize to enhance haematopoietic reconstitution in irradiated mice

    Energy Technology Data Exchange (ETDEWEB)

    Pospisil, M.; Hofer, M.; Netikova, J.; Hola, J.; Vacek, A. [Academy of Sciences of the Czech Republic, Inst. of Biophysics, Brno (Czech Republic); Znojil, V.; Vacha, J. [Masaryk Univ., Medical Faculty, Brno (Czech Republic)

    1998-03-01

    The activation of adenosine receptors has recently been demonstrated to stimulate haematopoiesis. In the present study, we investigated the ability of drugs elevating extracellular adenosine to influence curative effects of granulocyte colony-stimulating factor (G-CSF) in mice exposed to a sublethal dose of 4 Gy of {sup 60}Co radiation. Elevation of extracellular adenosine in mice was induced by the combined administration of dipyridamole, a drug inhibiting the cellular uptake of adenosine, and adenosine monophosphate (AMP), an adenosine prodrug. The effects of dipyridamole plus AMP, and G-CSF, administered either alone or in combination, were evaluated. The drugs were injected to mice in a 4-d treatment regimen starting on d 3 after irradiation and the haematopoietic response was evaluated on d 7, 10, 14, 18 and 24 after irradiation. While the effects of G-CSF on the late maturation stages of blood cells, appearing shortly after the completion of the treatment, were not influenced by dipyridamole plus AMP, positive effects of the combination therapy occurred in the post-irradiation recovery phase which is dependent on the repopulation of haematopoietic stem cells. This was indicated by the significant elevation of counts of granulocyte-macrophage progenitor cells (GM-CFC) and granulocytic cells in the bone marrow (d 14), of GM-CFC (d 14), granulocytic and erythroid cells (d 14 and 18) in the spleen, and of neutrophils (d 18), monocytes (d 14 and 18) and platelets (d 18) in the peripheral blood. These effects suggest that the repopulation potential of the combination therapy lies in a common multi-lineage cell population. The results of this study implicate the promising possibility to enhance the curative effects of G-CSF under conditions of myelosuppressive state induced by radiation exposure. (au) 43 refs.

  4. Value of the adenosine test for diagnosis of dual AV nodal physiology in patients with AV nodal reentrant tachycardia

    Institute of Scientific and Technical Information of China (English)

    周斌全; 胡申江; 等

    2002-01-01

    Objectives:This study was aimed at assessing the value of the adenosine test for noninvasive diagnosis of dual AV nodal physiology(DAVNP) in patients with AV nodal reentrant tachycardia(VANRT).Methods:53 patients with paroxysmal supraventricular tachycardia(PSVT) were given incremental doses of adenosine intravenously during sinus rhythm before electrophysiological study.The adenosine test was repeated on a subset of 18 patients with AVNRT after radiofrequency catheter ablation.Results:Sudden increments of PR interval of more than 60 msec between two consecutive beats were observed in 26(83.9%) of 31 patients with typical AVNRT and 2(9.1%) of 22 patients with AVRT and AT(P<0.01),The maximal PR increment between 2 consecutive beats in the AVNRT group(105±45ms) was significantly greater than that in the AVRT and AT group[(20±13ms) (P<0.01),In postablation adenosine test,DAVNP was eliminated in all 8 patients who underwent slow pathway abolition that EPS showed the slow pathway disappeared and 4 of 10 patients who underwent slow pathway modification that EPS showed the slow pathway disappeared and 4 of 10 patients who underwent slow pathway modification that EPS whosed the slow pathway persisted.Six of 10 patients whw exhibited persistent duality showed a marked reduction in the number of beats conducted in the slow pathway after adenosine injection(P<0.01),COnclusions:Administration of adenosine during sinus rhythm may be a useful bedside test for diagnosis of DAVNP in high percentage of patients with typical AVNRT and additionally for evaluating the effects of radiofrequency ablation.

  5. Decreased extracellular adenosine levels lead to loss of hypoxia-induced neuroprotection after repeated episodes of exposure to hypoxia.

    Directory of Open Access Journals (Sweden)

    Mei Cui

    Full Text Available Achieving a prolonged neuroprotective state following transient ischemic attacks (TIAs is likely to effectively reduce the brain damage and neurological dysfunction associated with recurrent stroke. HPC is a phenomenon in which advanced exposure to mild hypoxia reduces the stroke volume produced by a subsequent TIA. However, this neuroprotection is not long-lasting, with the effects reaching a peak after 3 days. Therefore, in this study, we investigated the use of multiple episodes of hypoxic exposure at different time intervals to induce longer-term protection in a mouse stroke model. C57BL/6 mice were subjected to different hypoxic preconditioning protocols: a single episode of HPC or five identical episodes at intervals of 3 days (E3d HPC or 6 days (E6d HPC. Three days after the last hypoxic exposure, temporary middle cerebral artery occlusion (MCAO was induced. The effects of these HPC protocols on hypoxia-inducible factor (HIF regulated gene mRNA expression were measured by quantitative PCR. Changes in extracellular adenosine concentrations, known to exert neuroprotective effects, were also measured using in vivo microdialysis and high pressure liquid chromatography (HPLC. Neuroprotection was provided by E6d HPC but not E3d HPC. HIF-regulated target gene expression increased significantly following all HPC protocols. However, E3d HPC significantly decreased extracellular adenosine and reduced cerebral blood flow in the ischemic region with upregulated expression of the adenosine transporter, equilibrative nucleoside transporter 1 (ENT1. An ENT1 inhibitor, propentofylline increased the cerebral blood flow and re-established neuroprotection in E3d HPC. Adenosine receptor specific antagonists showed that adenosine mainly through A1 receptor mediates HPC induced neuroprotection. Our data indicate that cooperation of HIF-regulated genes and extracellular adenosine is necessary for HPC-induced neuroprotection.

  6. The Quintiles Prize Lecture 2004. The identification of the adenosine A2B receptor as a novel therapeutic target in asthma.

    Science.gov (United States)

    Holgate, Stephen T

    2005-08-01

    Adenosine is a powerful bronchoconstrictor of asthmatic, but not normal, airways. In vitro studies on isolated human mast cells and basophils revealed that adenosine and selective analogues augmented inflammatory mediator release from mast cells by stimulating A(2) receptors. Pharmacological blockade of mast cell mediator release in vivo also attenuated adenosine-induced bronchoconstriction, as did theophylline, by adenosine A(2) receptor antagonism. Further in vitro studies revealed that the asthmatic response to adenosine is likely to be mediated via the A(2B) subtype which is selectively antagonised by enprofylline. Studies in animal models, especially mice, have shown a close synergistic interaction between adenosine, Th2 and airway remodelling responses. The recent description of A(2B) receptors on human airway smooth muscle cells that mediate cytokine and chemokine release and induce differentiation of fibroblasts into myofibroblasts strengthens the view that adenosine maybe more than an inflammatory mediator in asthma but also participates in airway wall remodelling in this disease. These data have provided a firm basis for developing adenosine A(2B) receptor antagonists as a new therapeutic approach to this disease. PMID:15980878

  7. The Quintiles Prize Lecture 2004: The identification of the adenosine A2B receptor as a novel therapeutic target in asthma

    Science.gov (United States)

    Holgate, Stephen T

    2005-01-01

    Adenosine is a powerful bronchoconstrictor of asthmatic, but not normal, airways. In vitro studies on isolated human mast cells and basophils revealed that adenosine and selective analogues augmented inflammatory mediator release from mast cells by stimulating A2 receptors. Pharmacological blockade of mast cell mediator release in vivo also attenuated adenosine-induced bronchoconstriction, as did theophylline, by adenosine A2 receptor antagonism. Further in vitro studies revealed that the asthmatic response to adenosine is likely to be mediated via the A2B subtype which is selectively antagonised by enprofylline. Studies in animal models, especially mice, have shown a close synergistic interaction between adenosine, Th2 and airway remodelling responses. The recent description of A2B receptors on human airway smooth muscle cells that mediate cytokine and chemokine release and induce differentiation of fibroblasts into myofibroblasts strengthens the view that adenosine maybe more than an inflammatory mediator in asthma but also participates in airway wall remodelling in this disease. These data have provided a firm basis for developing adenosine A2B receptor antagonists as a new therapeutic approach to this disease. PMID:15980878

  8. The Quintiles Prize Lecture 2004. The identification of the adenosine A2B receptor as a novel therapeutic target in asthma.

    Science.gov (United States)

    Holgate, Stephen T

    2005-08-01

    Adenosine is a powerful bronchoconstrictor of asthmatic, but not normal, airways. In vitro studies on isolated human mast cells and basophils revealed that adenosine and selective analogues augmented inflammatory mediator release from mast cells by stimulating A(2) receptors. Pharmacological blockade of mast cell mediator release in vivo also attenuated adenosine-induced bronchoconstriction, as did theophylline, by adenosine A(2) receptor antagonism. Further in vitro studies revealed that the asthmatic response to adenosine is likely to be mediated via the A(2B) subtype which is selectively antagonised by enprofylline. Studies in animal models, especially mice, have shown a close synergistic interaction between adenosine, Th2 and airway remodelling responses. The recent description of A(2B) receptors on human airway smooth muscle cells that mediate cytokine and chemokine release and induce differentiation of fibroblasts into myofibroblasts strengthens the view that adenosine maybe more than an inflammatory mediator in asthma but also participates in airway wall remodelling in this disease. These data have provided a firm basis for developing adenosine A(2B) receptor antagonists as a new therapeutic approach to this disease.

  9. Measuring the dynamics of cyclic adenosine monophosphate level in living cells induced by low-level laser irradiation using bioluminescence resonance energy transfer

    Science.gov (United States)

    Huang, Yimei; Zheng, Liqin; Yang, Hongqin; Chen, Jiangxu; Wang, Yuhua; Li, Hui; Xie, Shusen; Zeng, Haishan

    2015-05-01

    Several studies demonstrated that the cyclic adenosine monophosphate (cAMP), an important second messenger, is involved in the mechanism of low-level laser irradiation (LLLI) treatment. However, most of these studies obtained the cAMP level in cell culture extracts or supernatant. In this study, the cAMP level in living cells was measured with bioluminescence resonance energy transfer (BRET). The effect of LLLI on cAMP level in living cells with adenosine receptors blocked was explored to identify the role of adenosine receptors in LLLI. The results showed that LLLI increased the cAMP level. Moreover, the rise of cAMP level was light dose dependent but wavelength independent for 658-, 785-, and 830-nm laser light. The results also exhibited that the adenosine receptors, a class of G protein-coupled receptor (GPCR), modulated the increase of cAMP level induced by LLLI. The cAMP level increased more significantly when the A3 adenosine receptors (A3R) were blocked by A3R antagonist compared with A1 adenosine receptor or A2a adenosine receptor blocked in HEK293T cells after LLLI, which was in good agreement with the adenosine receptors' expressions. All these results suggested that measuring the cAMP level with BRET could be a useful technique to study the role of GPCRs in living cells under LLLI.

  10. Plasma membrane Ca2+ pumping plays a prominent role in adenosine A(1) receptor mediated changes in [Ca2+](i) in DDT1 MF-2 cells

    NARCIS (Netherlands)

    Sipma, H; Fredholm, BB; DenHertog, A; Nelemans, A

    1996-01-01

    Adenosine A(1) receptor mediated formation of inositol 1,4,5-trisphosphate (Ins(1,4,5)P-3) and accumulation of cytoplasmic Ca2+ ([Ca2+](i)) were investigated in DDT1 MF-2 smooth muscle cells. A strong reduction of the adenosine and N-6-cyclopentyladenosine (CPA) induced rise in [Ca2+](i) was observe

  11. CF102 an A3 Adenosine Receptor Agonist Mediates Anti-Tumor and Anti-Inflammatory Effects in the Liver

    OpenAIRE

    Cohen, S.; Stemmer, S M; ZOZULYA, G.; Ochaion, A.; PATOKA, R.; Barer, F.; BAR-YEHUDA, S.; RATH-WOLFSON, L.; Jacobson, K. A.; Fishman, P

    2011-01-01

    The Gi protein-associated A3 adenosine receptor (A3AR) is a member of the adenosine receptor family. Selective agonists at the A3AR, such as CF101 and CF102 were found to induce anti-inflammatory and anti-cancer effects. In this study, we examined the differential effect of CF102 in pathological conditions of the liver. The anti-inflammatory protective effect of CF101 was tested in a model of liver inflammation induced by Concanavalin A (Con. A) and the anti-cancer effect of CF102 was examine...

  12. Icariin upregulates phosphorylated cyclic adenosine monophosphate response element binding protein levels in the hippocampus of the senescence- accelerated mouse

    Institute of Scientific and Technical Information of China (English)

    Zhanwei Zhang; Ting Zhang; Keli Dong

    2012-01-01

    At 8 weeks after intragastric administration of icariin to senescence-accelerated mice (P8 strain), Morris water maze results showed that escape latency was shortened, and the number of platform crossings was increased. Immunohistochemical staining and western blot assay detected signifi-cantly increased levels of cyclic adenosine monophosphate response element binding protein. These results suggest that icariin upregulates phosphorylated cyclic adenosine monophosphate response element binding protein levels and improves learning and memory functions in hippo-campus of the senescence-accelerated mouse.

  13. Adenosine receptors located in the NTS contribute to renal sympathoinhibition during hypotensive phase of severe hemorrhage in anesthetized rats.

    Science.gov (United States)

    Scislo, Tadeusz J; O'Leary, Donal S

    2006-11-01

    Stimulation of nucleus of the solitary tract (NTS) A(2a)-adenosine receptors elicits cardiovascular responses quite similar to those observed with rapid, severe hemorrhage, including bradycardia, hypotension, and inhibition of renal but activation of preganglionic adrenal sympathetic nerve activity (RSNA and pre-ASNA, respectively). Because adenosine levels in the central nervous system increase during severe hemorrhage, we investigated to what extent these responses to hemorrhage may be due to activation of NTS adenosine receptors. In urethane- and alpha-chloralose-anesthetized male Sprague-Dawley rats, rapid hemorrhage was performed before and after bilateral nonselective or selective blockade of NTS adenosine-receptor subtypes [A(1)- and A(2a)-adenosine-receptor antagonist 8-(p-sulfophenyl)theophylline (1 nmol/100 nl) and A(2a)-receptor antagonist ZM-241385 (40 pmol/100 nl)]. The nonselective blockade reversed the response in RSNA (-21.0 +/- 9.6 Delta% vs. +7.3 +/- 5.7 Delta%) (where Delta% is averaged percent change from baseline) and attenuated the average heart rate response (change of -14.8 +/- 4.8 vs. -4.4 +/- 3.4 beats/min). The selective blockade attenuated the RSNA response (-30.4 +/- 5.2 Delta% vs. -11.1 +/- 7.7 Delta%) and tended to attenuate heart rate response (change of -27.5 +/- 5.3 vs. -15.8 +/- 8.2 beats/min). Microinjection of vehicle (100 nl) had no significant effect on the responses. The hemorrhage-induced increases in pre-ASNA remained unchanged with either adenosine-receptor antagonist. We conclude that adenosine operating in the NTS via A(2a) and possibly A(1) receptors may contribute to posthemorrhagic sympathoinhibition of RSNA but not to the sympathoactivation of pre-ASNA. The differential effects of NTS adenosine receptors on RSNA vs. pre-ASNA responses to hemorrhage supports the hypothesis that these receptors are differentially located/expressed on NTS neurons/synaptic terminals controlling different sympathetic outputs.

  14. Moderate exercise training promotes adaptations in coronary blood flow and adenosine production in normotensive rats

    Directory of Open Access Journals (Sweden)

    Fernanda R. Roque

    2011-01-01

    Full Text Available OBJECTIVES: Aerobic exercise training prevents cardiovascular risks. Regular exercise promotes functional and structural adaptations that are associated with several cardiovascular benefits. The aim of this study is to investigate the effects of swimming training on coronary blood flow, adenosine production and cardiac capillaries in normotensive rats. METHODS: Wistar rats were randomly divided into two groups: control (C and trained (T. An exercise protocol was performed for 10 weeks and 60 min/day with a tail overload of 5% bodyweight. Coronary blood flow was quantified with a color microsphere technique, and cardiac capillaries were quantified using light microscopy. Adenine nucleotide hydrolysis was evaluated by enzymatic activity, and protein expression was evaluated by western blot. The results are presented as the means ± SEMs (p<0.05. RESULTS: Exercise training increased the coronary blood flow and the myocardial capillary-to-fiber ratio. Moreover, the circulating and cardiac extracellular adenine nucleotide hydrolysis was higher in the trained rats than in the sedentary rats due to the increased activity and protein expression of enzymes, such as E-NTPDase and 59- nucleotidase. CONCLUSIONS: Swimming training increases coronary blood flow, number of cardiac capillaries, and adenine nucleotide hydrolysis. Increased adenosine production may be an important contributor to the enhanced coronary blood flow and angiogenesis that were observed in the exercise-trained rats; collectively, these results suggest improved myocardial perfusion.

  15. Modulatory effect of iron chelators on adenosine deaminase activity and gene expression in Trichomonas vaginalis.

    Science.gov (United States)

    Primon-Barros, Muriel; Rigo, Graziela Vargas; Frasson, Amanda Piccoli; Santos, Odelta dos; Smiderle, Lisiane; Almeida, Silvana; Macedo, Alexandre José; Tasca, Tiana

    2015-11-01

    Trichomonas vaginalis is a flagellate protozoan that parasitises the urogenital human tract and causes trichomoniasis. During the infection, the acquisition of nutrients, such as iron and purine and pyrimidine nucleosides, is essential for the survival of the parasite. The enzymes for purinergic signalling, including adenosine deaminase (ADA), which degrades adenosine to inosine, have been characterised in T. vaginalis. In the evaluation of the ADA profile in different T. vaginalis isolates treated with different iron sources or with limited iron availability, a decrease in activity and an increase in ADA gene expression after iron limitation by 2,2-bipyridyl and ferrozine chelators were observed. This supported the hypothesis that iron can modulate the activity of the enzymes involved in purinergic signalling. Under bovine serum limitation conditions, no significant differences were observed. The results obtained in this study allow for the assessment of important aspects of ADA and contribute to a better understanding of the purinergic system in T. vaginalis and the role of iron in establishing infection and parasite survival.

  16. A 24-Year Enzyme Replacement Therapy in an Adenosine-deaminase-Deficient Patient.

    Science.gov (United States)

    Tartibi, Hana M; Hershfield, Michael S; Bahna, Sami L

    2016-01-01

    Severe combined immunodeficiency (SCID) is a fatal childhood disease unless immune reconstitution is performed early in life, with either hematopoietic stem cell transplantation or gene therapy. One of its subtypes is caused by adenosine deaminase (ADA) enzyme deficiency, which leads to the accumulation of toxic metabolites that impair lymphocyte development and function. With the development of polyethylene glycol-conjugated adenosine deaminase (PEG-ADA) enzyme replacement therapy, many ADA-deficient children with SCID who could not receive a hematopoietic stem cell transplantation or gene therapy survived and had longer and healthier lives. We report a 24-year course of treatment in a patient who was diagnosed with ADA deficiency at 4 months of age. The patient was treated with PEG-ADA, which was the only therapy available for him. The patient's plasma ADA level was regularly monitored and the PEG-ADA dose adjusted accordingly. This treatment has resulted in near-normalization of lymphocyte counts, and his clinical course has been associated with only minor to moderate infections. Thus far, he has had no manifestations of autoimmune or lymphoproliferative disorders. This patient is among the longest to be maintained on PEG-ADA enzyme replacement therapy. PMID:26684479

  17. Robust aptamer sol-gel solid phase microextraction of very polar adenosine from human plasma.

    Science.gov (United States)

    Mu, Li; Hu, Xiangang; Wen, Jianping; Zhou, Qixing

    2013-03-01

    Conventional solid phase microextraction (SPME) has a limited capacity to extract very polar analytes, such as adenosine. To solve this problem, aptamer conjugating sol-gel methodology was coupled with an SPME fiber. According to the authors' knowledge, this is the first reported use of aptamer SPME. The fiber of aptamer sol-gel SPME with a mesoporous structure has high porosity, large surface area, and small water contact angle. Rather than employing direct entrapment, covalent immobilization was the dominant method of aptamer loading in sol-gel. Aptamer sol-gel fiber captured a specified analyte from among the analog molecules, thereby, exhibiting an excellent selective property. Compared with commercial SPME fibers, this aptamer fiber was suitable for extracting adenosine, presenting an extraction efficiency higher than 20-fold. The values of repeatability and reproducibility expressed by relative standard deviation were low (9.4%). Interestingly, the sol-gel network enhanced the resistance of aptamer SPME to both nuclease and nonspecific proteins. Furthermore, the aptamer sol-gel fiber was applied in human plasma with LOQ 1.5 μg/L, which is an acceptable level. This fiber also demonstrates durability and regeneration over 20-cycles without significant loss of efficiency. Given the various targets (from metal ions to biomacromolecules and cells) of aptamers, this methodology will extend the multi-domain applications of SPME.

  18. Cross sectional PET study of cerebral adenosine A1 receptors in premanifest and manifest Huntington's disease

    International Nuclear Information System (INIS)

    To study cerebral adenosine receptors (AR) in premanifest and manifest stages of Huntington's disease (HD). We quantified the cerebral binding potential (BPND) of the A1AR in carriers of the HD CAG trinucleotide repeat expansion using the radioligand [18 F]CPFPX and PET. Four groups were investigated: (i) premanifest individuals far (preHD-A; n = 7) or (ii) near (preHD-B; n = 6) to the predicted symptom onset, (iii) manifest HD patients (n = 8), and (iv) controls (n = 36). Cerebral A1AR values of preHD-A subjects were generally higher than those of controls (by up to 31 %, p 1AR BPND was observed to the levels of controls in preHD-B and undercutting controls in manifest HD by down to 25 %, p 1AR BPND and years to onset. Before onset of HD, the assumed annual rates of change of A1AR density were -1.2 % in the caudatus, -1.7 % in the thalamus and -3.4 % in the amygdala, while the corresponding volume losses amounted to 0.6 %, 0.1 % and 0.2 %, respectively. Adenosine receptors switch from supra to subnormal levels during phenoconversion of HD. This differential regulation may play a role in the pathophysiology of altered energy metabolism. (orig.)

  19. [Modification of phenylalanyl-tRNA-synthetase from Escherichia coli MRE600 by adenosine-5'-trimetaphosphate].

    Science.gov (United States)

    Khodyreva, S N; Nevinskiĭ, G A; Ankilova, V N; Lavrik, O I

    1983-01-01

    Modification of phenylalanyl-tRNA synthetase from E. coli MRE600 by adenosine-5'-trimetaphosphate, phosphorylating analog of ATP was shown to bring about the enzyme inactivation in the reactions of tRNA aminoacylation and ATP-[32P]pyrophosphate exchange. ATP when added in the reaction mixture protects the enzyme against inactivation in both reactions and decreases the level of covalent attachment of the analog. Phenylalanine has no protective effect. tRNA exhibits slight protective effect. Adenosine-5'-trimetaphosphate modifies both types (alpha and beta) of subunits of phenylalanyl-tRNA synthetase which is of alpha 2 beta 2 structure. ATP protects both types of the enzyme subunits against the covalent attachment of the analog. Disposition of the ATP-binding centers in the contact region of the nonequivalent subunits of the enzyme was proposed. The level of covalent attachment of the analog to the enzyme exceeds the number of the enzyme active sites that may be a consequence of the other nucleotide-binding center labeling. PMID:6361520

  20. The efficacy of a novel adenosine agonist (WAG 994) in postoperative dental pain

    Science.gov (United States)

    Seymour, R A; Hawkesford, J E; Hill, C M; Frame, J; Andrews, C

    1999-01-01

    Aims To determine the comparative efficacy of a new novel adenosine agonist (WAG 994) in postoperative pain after third molar surgery. Methods One hundred and twenty-two patients with postoperative pain after third molar surgery were randomised in a placebo double-blind trial with an active control group. In the early postoperative period patients received either a single dose of WAG 994 1 mg, ibuprofen 400 mg or matched placebos. Pain intensity score was recorded on serial visual analogue scales over a 6 h investigation period. Similarly, pain relief was completed on a 4 point categorical scale at each evaluation point. Patients had access to escape analgesic and if these were taken, the time and dosage were recorded. A sparse sampling technique was used to investigate the relationship between analgesic effects and plasma concentrations of WAG 994. Results All three treatment groups were matched for various demographic variables. For all efficacy measures, WAG 994 was not significantly different from placebo (P > 0.05), whereas ibuprofen 400 mg was significantly superior to placebo (P < 0.001). No significant relationships (P < 0.05) were found between WAG 994 pharmacokinetic variables and efficacy measures. Conclusion WAG 994, an adenosine agonist, did not show efficacy in the management of postoperative pain after third molar surgery. Although this pain responds well to nonsteroidal anti-inflammatory drugs, it appears to be resistant to compounds that interact with purinergic receptors. PMID:10383546

  1. Adenosine deaminase activity in serum and lymphocytes of rats infected with Sporothrix schenckii.

    Science.gov (United States)

    Castro, Verônica S P; Pimentel, Victor C; Da Silva, Aleksandro S; Thomé, Gustavo R; Wolkmer, Patrícia; Castro, Jorge L C; Costa, Márcio M; da Silva, Cássia B; Oliveira, Daniele C; Alves, Sydney H; Schetinger, Maria R C; Lopes, Sonia T A; Mazzanti, Cinthia M

    2012-07-01

    Sporotrichosis is a fungal infection of subcutaneous or chronic evolution, inflammatory lesions characterized by their pyogranulomatous aspect, caused by the dimorphic fungus Sporothrix schenckii. Adenosine deaminase (ADA) is a "key" enzyme in the purine metabolism, promoting the deamination of adenosine, an important anti-inflammatory molecule. The increase in ADA activity has been demonstrated in several inflammatory conditions; however, there are no data in the literature associated with this fungal infection. The objective of this study was to evaluate the activity of serum ADA (S-ADA) and lymphocytes (L-ADA) of rats infected with S. schenckii. We used seventy-eight rats divided into two groups. In the first experiment, rats were infected subcutaneously and in the second experiment, infected intraperitoneally. Blood samples for hematologic evaluation and activities of S-ADA and L-ADA were performed at days 15, 30, and 40 post-infection (PI) to assess disease progression. In the second experiment, it was observed an acute decrease in activity of S-ADA and L-ADA (P schenckii alters the activities of S-ADA in experimentally infected rats, demonstrating the involvement of this enzyme in the pathogenesis of sporotrichosis.

  2. Adenosine and Hypoxia-Inducible Factor Signaling in Intestinal Injury and Recovery

    Science.gov (United States)

    Eltzschig, Holger K.

    2013-01-01

    The gastrointestinal mucosa has proven to be an interesting tissue in which to investigate disease-related metabolism. In this review, we outline some of the evidence that implicates hypoxia-mediated adenosine signaling as an important signature within both healthy and diseased mucosa. Studies derived from cultured cell systems, animal models, and human patients have revealed that hypoxia is a significant component of the inflammatory microenvironment. These studies have revealed a prominent role for hypoxia-induced factor (HIF) and hypoxia signaling at several steps along the adenine nucleotide metabolism and adenosine receptor signaling pathways. Likewise, studies to date in animal models of intestinal inflammation have demonstrated an almost uniformly beneficial influence of HIF stabilization on disease outcomes. Ongoing studies to define potential similarities with and differences between innate and adaptive immune responses will continue to teach us important lessons about the complexity of the gastrointestinal tract. Such information has provided new insights into disease pathogenesis and, importantly, will provide insights into new therapeutic targets. PMID:21942704

  3. Development of gene therapy: potential in severe combined immunodeficiency due to adenosine deaminase deficiency

    Directory of Open Access Journals (Sweden)

    Claudia A Montiel-Equihua

    2009-12-01

    Full Text Available Claudia A Montiel-Equihua, Adrian J Thrasher, H Bobby GasparCentre for Immunodeficiency, Molecular Immunology Unit, UCL Institute of Child Health, London, UKAbstract: The history of stem cell gene therapy is strongly linked to the development of gene therapy for severe combined immunodeficiencies (SCID and especially adenosine deaminase (ADA-deficient SCID. Here we discuss the developments achieved in over two decades of clinical and laboratory research that led to the establishment of a protocol for the autologous transplant of retroviral vector-mediated gene-modified hematopoietic stem cells, which has proved to be both successful and, to date, safe. Patients in trials in three different countries have shown long-term immunological and metabolic correction. Nevertheless, improvements to the safety profile of viral vectors are underway and will undoubtedly reinforce the position of stem cell gene therapy as a treatment option for ADA-SCID.Keywords: adenosine deaminase, severe combined immunodeficiency, gene therapy, hematopoietic stem cell, retrovirus, clinical trial

  4. Formation of guanine ribonucleotidyl-(3'-5')-adenosine in a flavinogenic strain of Eremothecium ashbyii.

    Science.gov (United States)

    Mitsuda, H; Nishikawa, Y; Nakajima, K

    1976-01-01

    The addition of caffeine caused the accumulation of a new nucleotide compound simultaneously with the rigid inhibition of ribofalvin production in non-growing cells of Eremothecium ashbyii. In the present study we tried to identify the structure of the nucleotide compound using non-growing cells of the mold. 1) It became possible to obtain a large amount of mycelia by masscultivation in a reagent tank. 2) A new nucleotide compound, referred to as compound A in the paper, was extracted with perchloric acid solution and purified by the following subsequent procedures: 1) Dowex 1 x 2 (HCOO-) column, 2) charcoal treatment, 3) DEAE-Sephadex A25 (CI-) column, 4) Dowex 1 x 2 (C1-) column, and 5) DEAE-Sephadex A25 (HCO3-) column. 3) The structure of the new nucleotide compound was proved to be guanine ribonucleotidyl-(3'-5')-adenosine (GpA) from the results of the following analyses: 1) alkaline degradation, 2) UV-spectra, IR-spectra and NMR-spectra, and 3) enzymatic treatments with RNase T2 and phosphodiesterase. 4) The roles of caffeine and guanine ribonucleotidyl-(3'-5')-adenosine in connection with flavinogenesis of this mold were discussed. PMID:182940

  5. Uneven distribution of nucleoside transporters and intracellular enzymatic degradation prevent transport of intact [14C] adenosine across the sheep choroid plexus epithelium as a monolayer in primary culture

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    Misirlic Dencic Sonja T

    2006-03-01

    Full Text Available Abstract Background Efflux transport of adenosine across the choroid plexus (CP epithelium might contribute to the homeostasis of this neuromodulator in the extracellular fluids of the brain. The aim of this study was to explore adenosine transport across sheep CP epithelial cell monolayers in primary culture. Methods To explore transport of adenosine across the CP epithelium, we have developed a method for primary culture of the sheep choroid plexus epithelial cells (CPEC on plastic permeable supports and analysed [14C] adenosine transport across this cellular layer, [14C] adenosine metabolism inside the cells, and cellular uptake of [14C] adenosine from either of the chambers. The primary cell culture consisted of an enriched epithelial cell fraction from the sheep fourth ventricle CP and was grown on laminin-precoated filter inserts. Results and conclusion CPEC grew as monolayers forming typical polygonal islands, reaching optical confluence on the third day after the seeding. Transepithelial electrical resistance increased over the time after seeding up to 85 ± 9 Ω cm2 at day 8, while permeability towards [14C] sucrose, a marker of paracellular diffusion, simultaneously decreased. These cells expressed some features typical of the CPEC in situ, including three nucleoside transporters at the transcript level that normally mediate adenosine transport across cellular membranes. The estimated permeability of these monolayers towards [14C] adenosine was low and the same order of magnitude as for the markers of paracellular diffusion. However, inhibition of the intracellular enzymes, adenosine kinase and adenosine deaminase, led to a significant increase in transcellular permeability, indicating that intracellular phosphorylation into nucleotides might be a reason for the low transcellular permeability. HPLC analysis with simultaneous detection of radioactivity revealed that [14C] radioactivity which appeared in the acceptor chamber after the

  6. The pharmacological activation of adenosine A1 and A3 receptors does not modulate the long- or short-term repopulating ability of hematopoietic stem and multipotent progenitor cells in mice

    OpenAIRE

    Hofer, Michal; Pospíšil, Milan; Hoferová, Zuzana; Komůrková, Denisa; Páral, Petr; Savvulidi, Filipp; Šefc, Luděk

    2012-01-01

    This study continues our earlier findings on the hematopoiesis-modulating effects of adenosine A1 and A3 receptor agonists that were performed on committed hematopoietic progenitor and precursor cell populations. In the earlier experiments, N6-cyclopentyladenosine (CPA), an adenosine A1 receptor agonist, was found to inhibit proliferation in the above-mentioned hematopoietic cell systems, whereas N6-(3-iodobenzyl)adenosine-5′-N-methyluronamide (IB-MECA), an adenosine A3 receptor agonist, was ...

  7. Functional expression of adenosine A2A and A3 receptors in the mouse dendritic cell line XS-106.

    Science.gov (United States)

    Dickenson, John M; Reeder, Steve; Rees, Bob; Alexander, Steve; Kendall, Dave

    2003-08-01

    There is increasing evidence to suggest that adenosine receptors can modulate the function of cells involved in the immune system. For example, human dendritic cells derived from blood monocytes have recently been described to express functional adenosine A1, A2A and A3 receptors. Therefore, in the present study, we have investigated whether the recently established murine dendritic cell line XS-106 expresses functional adenosine receptors. The selective adenosine A3 receptor agonist 1-[2-chloro-6[[(3-iodophenyl)methyl]amino]-9H-purin-9-yl]-1-deoxy-N-methyl-beta-D-ribofuranuronamide (2-Cl-IB-MECA) inhibited forskolin-mediated [3H]cyclic AMP accumulation and stimulated concentration-dependent increases in p42/p44 mitogen-activated protein kinase (MAPK) phosphorylation. The selective adenosine A2A receptor agonist 4-[2-[[-6-amino-9-(N-ethyl-beta-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzene-propanoic acid (CGS 21680) stimulated a robust increase in [3H]cyclic AMP accumulation and p42/p44 MAPK phosphorylation. In contrast, the selective adenosine A1 receptor agonist CPA (N6-cyclopentyladenosine) did not inhibit forskolin-mediated [3H]cyclic AMP accumulation or stimulate increases in p42/p44 MAPK phosphorylation. These observations suggest that XS-106 cells express functional adenosine A2A and A3 receptors. The non-selective adenosine receptor agonist 5'-N-ethylcarboxamidoadenosine (NECA) inhibited lipopolysaccharide-induced tumour necrosis factor-alpha (TNF-alpha) release from XS-106 cells in a concentration-dependent fashion. Furthermore, treatment with Cl-IB-MECA (1 microM) or CGS 21680 (1 microM) alone produced a partial inhibition of lipopolysaccharide-induced TNF-alpha release (when compared to NECA), whereas a combination of both agonists resulted in the inhibition of TNF-alpha release comparable to that observed with NECA alone. Treatment of cells with the adenosine A2A receptor selective antagonists 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a

  8. Reproducibility of adenosine stress cardiovascular magnetic resonance in multi-vessel symptomatic coronary artery disease

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    Feneley Michael P

    2010-07-01

    Full Text Available Abstract Purpose First-pass perfusion cardiovascular magnetic resonance (CMR is increasingly being utilized in both clinical practice and research. However, the reproducibility of this technique remains incompletely evaluated, particularly in patients with severe coronary artery disease (CAD. The purpose of this study was to determine the inter-study reproducibility of adenosine stress CMR in patients with symptomatic multi-vessel CAD and those at low risk for CAD. Methods Twenty patients (10 with CAD, 10 low risk CAD underwent two CMR scans 8 ± 2 days apart. Basal, mid and apical left ventricular short axis slices were acquired using gadolinium 0.05 mmol/kg at peak stress (adenosine, 140 μ/kg/min, 4 min and rest. Myocardial perfusion was evaluated qualitatively by assessing the number of ischemic segments, and semi-quantitatively by determining the myocardial perfusion reserve index (MPRi using a normalized upslope method. Inter-study and observer reproducibility were assessed--the latter being defined by the coefficient of variation (CoV, which was calculated from the standard deviation of the differences of the measurements, divided by the mean. Additionally, the percentage of myocardial segments with perfect agreement and inter- and intra-observer MPRi correlation between studies, were also determined. Results The CoV for the number of ischemic segments was 31% with a mean difference of -0.15 ± 0.88 segments and 91% perfect agreement between studies. MPRi was lower in patients with CAD (1.13 ± 0.21 compared to those with low risk CAD (1.59 ± 0.58, p = 0.02. The reproducibility of MPRi was 19% with no significant difference between patients with CAD and those with low risk CAD (p = 0.850. Observer reproducibility for MPRi was high: inter-observer CoV 9%, r = 0.93 and intra-observer CoV 5%, r = 0.94. For trials using perfusion CMR as an endpoint, an estimated sample size of 12 subjects would be required to detect a two-segment change in

  9. Comparative study of adenosine deaminase activity, insulin resistance and lipoprotein(a among smokers and healthy non-smokers

    Directory of Open Access Journals (Sweden)

    Ramesh Ramasamy

    2016-06-01

    Conclusions: Adenosine deaminase activity was increased in patients in response to nicotine which is the key component of cigarette smoke. These findings indicate that nicotine and carbon monoxide can alter lipoprotein synthesis and also modify LDL to oxidized form which can lead to ischemic heart disease. [Int J Res Med Sci 2016; 4(6.000: 1950-1953

  10. Simultaneous determination of adenine,uridine and adenosine in cordyceps sinensis and its substitutes by LC/ESI-MS

    Institute of Scientific and Technical Information of China (English)

    黄兰芳; 吴名剑; 孙贤军; 郭方遒; 梁逸曾; 李晓如

    2004-01-01

    A simple, sensitive and reproducible high performance liquid chromatography-mass spectrometry coupled with electrospray ionization method for simultaneous separation and determination of adenine, adenosine and uridine was developed. The analytical column is a 2.0 mm× 150 mm Shimadzu VP-ODS column and volume fraction of the mobile phase is 86.5 %water, 12.0%methanol and 1.5%formic acid. 2-chloroadenosine was used as internal standard. Selective ion monitoring mode and selective ion monitoring ions at ratio of mass to electric charge of 136 for adenine, 268 for adenosine and 267 for uridine were chosen for quantitative analysis of the three active components. The results show that the regression equations and linear range are Y=0. 062X+0. 005 and 2.0 - 140.0μg · mL 1for adenine, Y=0. 049X+0. 004 and 4. 0 - 115.0 μg · mL-1 for uridine, Y=0. 154X+0. 014 and 1.0 - 125.0 μg · mL 1 for adenosine. The limits of detection are 0.6 μg · mL 1 for adenine, 1.0μg · mL-1 for uri dine and 0.2 μg · mL 1 for adenosine.The recoveries of the three constituents are from 96.6% to 103.2%.

  11. Synthesis and Properties of a New Water-Soluble Prodrug of the Adenosine A2A Receptor Antagonist MSX-2

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    Christa E. Müller

    2008-02-01

    Full Text Available The compound L-valine-3-{8-[(E-2-[3-methoxyphenylethenyl]-7-methyl-1-propargylxanthine-3-yl}propyl ester hydrochloride (MSX-4 was synthesized as an aminoacid ester prodrug of the adenosine A2A receptor antagonist MSX-2. It was found to bestable in artificial gastric acid, but readily cleaved by pig liver esterase.

  12. A3 Adenosine Receptor Allosteric Modulator Induces an Anti-Inflammatory Effect: In Vivo Studies and Molecular Mechanism of Action

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    Shira Cohen

    2014-01-01

    Full Text Available The A3 adenosine receptor (A3AR is overexpressed in inflammatory cells and in the peripheral blood mononuclear cells of individuals with inflammatory conditions. Agonists to the A3AR are known to induce specific anti-inflammatory effects upon chronic treatment. LUF6000 is an allosteric compound known to modulate the A3AR and render the endogenous ligand adenosine to bind to the receptor with higher affinity. The advantage of allosteric modulators is their capability to target specifically areas where adenosine levels are increased such as inflammatory and tumor sites, whereas normal body cells and tissues are refractory to the allosteric modulators due to low adenosine levels. LUF6000 administration induced anti-inflammatory effect in 3 experimental animal models of rat adjuvant induced arthritis, monoiodoacetate induced osteoarthritis, and concanavalin A induced liver inflammation in mice. The molecular mechanism of action points to deregulation of signaling proteins including PI3K, IKK, IκB, Jak-2, and STAT-1, resulting in decreased levels of NF-κB, known to mediate inflammatory effects. Moreover, LUF6000 induced a slight stimulatory effect on the number of normal white blood cells and neutrophils. The anti-inflammatory effect of LUF6000, mechanism of action, and the differential effects on inflammatory and normal cells position this allosteric modulator as an attractive and unique drug candidate.

  13. Elevation of extracellular adenosine enhances haemopoiesis-stimulating effects of G-CSF in normal and gamma-irradiated mice

    Energy Technology Data Exchange (ETDEWEB)

    Hofer, M.; Pospisil, M.; Netikiva, J.; Hola, J. [Institute of Biophysics, Academy of Sciences of the Czech Republic (Czech Republic)

    1997-03-01

    Effects of combined treatment with drugs elevating extracellular adenosine (dipyridamole /DP/, inhibiting the extracellular uptake of adenosine, and adenosine monophosphate /AMP/, an adenosine pro-drug), and G-CSF (granulocyte colony-stimulating factor) on haemopoiesis of normal and gamma-irradiated mice were ascertained. The agents were administered alone or in combination in a 4-day regimen. In normal, unirradiated animals, the haematological endpoints were determined 24 hours after the completion of the treatment. It was shown that the effects of G-CSF, i.e., increases in peripheral blood neutrophils, granulocyte-macrophage progenitor cells (GM-CFC) and morphologically recognizable granulocyte cells in femoral marrow and a decrease in the marrow erythroid cells, can be enhanced by the combination of DP plus AMP administrated 30 minutes before G-CSF. Furthermore, it was found that the stimulatory action of DP plus AMP was expressed particularly at lower doses of G-CSF (1.5, 3, and 4.5 {mu}g/d). In experiments with irradiated mice, when the 4-day therapeutic regimen was applied on days 3 to 6 following irradiation with the dose of 4 Gy, analogical stimulation of granulopoiesis was observed in the recovery phase on days 14 and 18 after irradiation. As example, see Fig. 1 for counts of granulocyte cells in femoral bone marrow. (authors)

  14. Microwave-assisted Green and Efficient Synthesis of N6-(2-Hydroxyethyl)adenosine and its Analogues

    Institute of Scientific and Technical Information of China (English)

    Gui Rong QU; Ming Wei GENG; Su Hui HAN; Zhi Guang ZHANG; Feng XUE

    2006-01-01

    An efficient protocol for the synthesis of N6-(2-Hydroxyethyl)adenosine and its analogues through nucleophilic substitution was developed. All the reactions were completed in 10 min under microwave irradiation. Using water as solvent makes our method eco-friendly and easy to handle with.

  15. Determination of serum adenosine deaminase and xanthine oxidase levels in patients with crimean-congo hemorrhagic fever

    Directory of Open Access Journals (Sweden)

    V. Kenan Celik

    2010-01-01

    Full Text Available OBJECTIVE: Crimean-Congo hemorrhagic fever is an acute viral hemorrhagic fever with a high mortality rate. Despite increasing knowledge about hemorrhagic fever viruses, little is known about the pathogenesis of Crimean-Congo hemorrhagic fever. In this study, we measured serum adenosine deaminase and xanthine oxidase levels in Crimean-Congo hemorrhagic fever patients. METHODS: Serum adenosine deaminase levels were measured with a sensitive colorimetric method described by Giusti and xanthine oxidase levels by the method of Worthington in 30 consecutive hospitalized patients (mean age 42.6 ± 21.0. Laboratory tests confirmed their diagnoses of Crimean-Congo hemorrhagic fever. Thirty-five subjects (mean age 42.9 ± 19.1 served as the control group. RESULTS: There was a significant difference in adenosine deaminase and xanthine oxidase levels between cases and controls (p0.05. CONCLUSION: Adenosine deaminase and xanthine oxidase levels were increased in patients with Crimean-Congo hemorrhagic fever. Elevated serum xanthine oxidase activity in patients with Crimean-Congo hemorrhagic fever may be associated with reactive oxygen species generated by the xanthine/xanthine oxidase system during inflammatory responses. In addition, elevated lipid peroxidation may contribute to cell damage and hemorrhage. The association of cell damage and hemorrhage with xanthine oxidase activity should be further investigated in large-scale studies.

  16. Elevation of extracellular adenosine enhances haemopoiesis-stimulating effects of G-CSF in normal and gamma-irradiated mice

    International Nuclear Information System (INIS)

    Effects of combined treatment with drugs elevating extracellular adenosine (dipyridamole /DP/, inhibiting the extracellular uptake of adenosine, and adenosine monophosphate /AMP/, an adenosine pro-drug), and G-CSF (granulocyte colony-stimulating factor) on haemopoiesis of normal and gamma-irradiated mice were ascertained. The agents were administered alone or in combination in a 4-day regimen. In normal, unirradiated animals, the haematological endpoints were determined 24 hours after the completion of the treatment. It was shown that the effects of G-CSF, i.e., increases in peripheral blood neutrophils, granulocyte-macrophage progenitor cells (GM-CFC) and morphologically recognizable granulocyte cells in femoral marrow and a decrease in the marrow erythroid cells, can be enhanced by the combination of DP plus AMP administrated 30 minutes before G-CSF. Furthermore, it was found that the stimulatory action of DP plus AMP was expressed particularly at lower doses of G-CSF (1.5, 3, and 4.5 μg/d). In experiments with irradiated mice, when the 4-day therapeutic regimen was applied on days 3 to 6 following irradiation with the dose of 4 Gy, analogical stimulation of granulopoiesis was observed in the recovery phase on days 14 and 18 after irradiation. As example, see Fig. 1 for counts of granulocyte cells in femoral bone marrow. (authors)

  17. DNA-templated silver nanoclusters based label-free fluorescent molecular beacon for the detection of adenosine deaminase.

    Science.gov (United States)

    Zhang, Kai; Wang, Ke; Xie, Minhao; Zhu, Xue; Xu, Lan; Yang, Runlin; Huang, Biao; Zhu, Xiaoli

    2014-02-15

    A general and reliable fluorescent molecular beacon is proposed in this work utilizing DNA-templated silver nanoclusters (AgNCs). The fluorescent molecular beacon has been employed for sensitive determination of the concentration of adenosine deaminase (ADA) and its inhibition. A well-designed oligonucleotide containing three functional regions (an aptamer region for adenosine assembly, a sequence complementary to the region of the adenosine aptamer, and an inserted six bases cytosine-loop) is adopted as the core element in the strategy. The enzymatic reaction of adenosine catalyzed by ADA plays a key role as well in the regulation of the synthesis of the DNA-templated AgNCs, i.e. the signal indicator. The intensity of the fluorescence signal may thereby determine the concentration of the enzyme and its inhibitor. The detection limit of the ADA can be lowered to 0.05 UL(-1). Also, 100 fM of a known inhibitor erythro-9-(2-hydroxy-3-nonyl) adenine hydrochloride (EHNA) is enough to present distinguishable fluorescence emission. Moreover, since the fluorescent signal indicator is not required to be bound with the oligonucleotide, this fluorescent molecular beacon may integrate the advantages of both the label-free and signal-on strategies.

  18. Bronchial responsiveness to adenosine 5 '-monophosphate (AMP) and methacholine differ in their relationship with airway allergy and baseline FEV

    NARCIS (Netherlands)

    De Meer, G; Heederik, D; Postma, DS

    2002-01-01

    Bronchial hyperresponsiveness (BHR) and inflammation are central hallmarks of asthma. Studies in patients with asthma suggest that BHR to adenosine 5'-monophosphate (AMP) is a better marker of bronchial inflammation than BHR to methacholine. The association between markers of airway inflammation and

  19. Comparison of interferon-gamma release assays and adenosine deaminase of pleural fluid for the diagnosis of pleural tuberculosis

    Institute of Scientific and Technical Information of China (English)

    刘菲

    2014-01-01

    Objective To compare the diagnostic performance of interferon gamma releasing assays(T-SPOT.TB)and adenosine deaminase(ADA)in pleural tuberculosis,and therefore to evaluate the value of T-SPOT.TB in a high tuberculosis burden country.Methods From June 2011to November 2012,111 patients with pleural fluid in Beijing Chest Hospital,Capital Medical University were

  20. Diagnostic Accuracy of Adenosine Stress Cardiovascular Magnetic Resonance Following Acute ST-segment Elevation Myocardial Infarction Post Primary Angioplasty

    Directory of Open Access Journals (Sweden)

    Wong Dennis TL

    2011-10-01

    Full Text Available Abstract Background Adenosine stress cardiovascular magnetic resonance (CMR has been proven an effective tool in detection of reversible ischemia. Limited evidence is available regarding its accuracy in the setting of acute coronary syndromes, particularly in evaluating the significance of non-culprit vessel ischaemia. Adenosine stress CMR and recent advances in semi-quantitative image analysis may prove effective in this area. We sought to determine the diagnostic accuracy of semi-quantitative versus visual assessment of adenosine stress CMR in detecting ischemia in non-culprit territory vessels early after primary percutaneous coronary intervention (PCI for ST-segment elevation myocardial infarction (STEMI. Methods Patients were prospectively enrolled in a CMR imaging protocol with rest and adenosine stress perfusion, viability and cardiac functional assessment 3 days after successful primary-PCI for STEMI. Three short axis slices each divided into 6 segments on first pass adenosine perfusion were visually and semi-quantitatively analysed. Diagnostic accuracy of both methods was compared with non-culprit territory vessels utilising quantitative coronary angiography (QCA with significant stenosis defined as ≥70%. Results Fifty patients (age 59 ± 12 years admitted with STEMI were evaluated. All subjects tolerated the adenosine stress CMR imaging protocol with no significant complications. The cohort consisted of 41% anterior and 59% non anterior infarctions. There were a total of 100 non-culprit territory vessels, identified on QCA. The diagnostic accuracy of semi-quantitative analysis was 96% with sensitivity of 99%, specificity of 67%, positive predictive value (PPV of 97% and negative predictive value (NPV of 86%. Visual analysis had a diagnostic accuracy of 93% with sensitivity of 96%, specificity of 50%, PPV of 97% and NPV of 43%. Conclusion Adenosine stress CMR allows accurate detection of non-culprit territory stenosis in patients