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Sample records for adenosine disodium triphosphate

  1. Determination of adenosine disodium triphosphate using prulifloxacin-terbium(III) as a fluorescence probe by spectrofluorimetry

    International Nuclear Information System (INIS)

    Yu Fengshan; Li Lin; Chen Fang

    2008-01-01

    A new spectrofluorimetric method is developed for determination of adenosine disodium triphosphate (ATP). The interactions between prulifloxacin (PUFX)-Tb 3+ complex and adenosine disodium triphosphate has been studied by using UV-vis absorption and fluorescence spectra. Using prulifloxacin-Tb 3+ as a fluorescence probe, under the optimum conditions, ATP can remarkably enhance the fluorescence intensity of the prulifloxacin-Tb 3+ complex at λ = 545 nm and the enhanced fluorescence intensity is in proportion to the concentration of ATP. Optimum conditions for the determination of ATP were also investigated. The dynamic range for the determination of ATP is 4.0 x 10 -7 to 2.0 x 10 -5 mol L -1 , and the detection limit (3 σ/k) is 1.7 x 10 -8 mol L -1 . This method is simple, practical and relatively free interference from coexisting substances and can be successfully applied to determination of ATP in real pharmaceutical samples. The mechanism of fluorescence enhancement of prulifloxacin-Tb 3+ complex by ATP was also discussed

  2. Spectroscopic study of the interaction between adenosine disodium triphosphate and gatifloxacin-Al3+ complex and its analytical application.

    Science.gov (United States)

    Kamruzzaman, Mohammad; Faruqui, A Nayeem; Hossain, Mohammed Ifteker; Lee, Sang Hak

    2015-11-01

    A new and sensitive spectrofluorimetric method has been proposed to determine trace amount of adenosine disodium triphosphate (ATP). The method is based on the fluorimetric interaction between gatifloxacin (GFLX)-aluminium (III) (Al(3+) ) complex and ATP and studied using UV-visible and fluorescence spectroscopy. Weak luminescence spectra of Al(3+) were enhanced after complexation with GFLX at 423 nm upon excitation at 272 nm due to energy transfer from the ligand to the Al(3+) ion. It was observed that the FL emission spectrum of GFLX-Al(3+) was enhanced significantly by the addition of ATP. Under the optimal conditions, the enhancement of FL intensity at 423 nm was responded linearly with the concentration of ATP in the range 1.3 × 10(-10) - 1.0 × 10(-8) mol L(-1) with correlation coefficient (r) of 0.9981. The limit of detection (LOD) was found to be 1.1 × 10(-11) mol L(-1) for ATP with the standard deviation (RSD) of 1.21% for five repeated measurement of 2.3 × 10(-8) mol L(-1) ATP. The presented method is simple, sensitive, free from coexisting interferents and can be applied successfully to determine ATP in the real samples. Copyright © 2015 John Wiley & Sons, Ltd.

  3. Yolk-Shell Porous Microspheres of Calcium Phosphate Prepared by Using Calcium L-Lactate and Adenosine 5'-Triphosphate Disodium Salt: Application in Protein/Drug Delivery.

    Science.gov (United States)

    Ding, Guan-Jun; Zhu, Ying-Jie; Qi, Chao; Sun, Tuan-Wei; Wu, Jin; Chen, Feng

    2015-06-26

    A facile and environmentally friendly approach has been developed to prepare yolk-shell porous microspheres of calcium phosphate by using calcium L-lactate pentahydrate (CL) as the calcium source and adenosine 5'-triphosphate disodium salt (ATP) as the phosphate source through the microwave-assisted hydrothermal method. The effects of the concentration of CL, the microwave hydrothermal temperature, and the time on the morphology and crystal phase of the product are investigated. The possible formation mechanism of yolk-shell porous microspheres of calcium phosphate is proposed. Hemoglobin from bovine red cells (Hb) and ibuprofen (IBU) are used to explore the application potential of yolk-shell porous microspheres of calcium phosphate in protein/drug loading and delivery. The experimental results indicate that the as-prepared yolk-shell porous microspheres of calcium phosphate have relatively high protein/drug loading capacity, sustained protein/drug release, favorable pH-responsive release behavior, and a high biocompatibility in the cytotoxicity test. Therefore, the yolk-shell porous microspheres of calcium phosphate have promising applications in various biomedical fields such as protein/drug delivery. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Sensitive determination of adenosine disodium triphosphate in soil, milk, and pharmaceutical formulation by enoxacin–europium (III) fluorescence complex in solution

    International Nuclear Information System (INIS)

    Alam, Al-Mahmnur; Kamruzzaman, Mohammad; Hak Lee, Sang; Ho Kim, Young; Jin Jo, Hae; Hong Kim, Sung; Park, Sang-Ryoul

    2012-01-01

    A new spectroflurometric method for the determination of adenosine disodium triphosphate (ATP) is developed. Fluorometric interaction between ATP and enoxacin (ENX)–Eu 3+ complex was studied using UV–vis and fluorescence spectroscopy. Weak luminescence spectra of Eu 3+ were enhanced after complexation with ENX at 589 nm and 614 nm upon excitation at 395 nm due to energy transfer from the ligand to the lanthanide ion. It was observed that luminescence spectrum of Eu 3+ was strongly enhanced further at 614 nm after incorporation of ATP into the ENX–Eu 3+ complex. Under optimal conditions, the enhancement of luminescence at 614 nm was responded linearly with the concentration of ATP. The linearity was maintained in the range of 1.5×10 −10 –1.15×10 −8 M (R=0.9973) with the limit of detection (3σ) of 4.71×10 −11 M. The relative standard deviation (RSD) for 9 repeated measurements of 1×10 −9 M ATP was 1.25%. Successful determinations of ATP in soil, milk, and a pharmaceutical formulation with the proposed method were demonstrated. - Highlights: ► Weak luminescence of Eu 3+ was enhanced at 614 nm after formation of complex with ENX. ► Energy transfer occurs through FRET from ENX to Eu 3+ upon excitation. ► Luminescence signal was further enhanced when ATP conjugates with ENX–Eu 3+ complex. ► Luminescence intensity of Eu 3+ at 614 nm was correlated with concentration of ATP. ► The method was applied to determine ATP in soil, milk, and pharmaceutical samples.

  5. Oral sucrose for heel lance enhances adenosine triphosphate use in preterm neonates with respiratory distress.

    Science.gov (United States)

    Angeles, Danilyn M; Asmerom, Yayesh; Boskovic, Danilo S; Slater, Laurel; Bacot-Carter, Sharon; Bahjri, Khaled; Mukasa, Joseph; Holden, Megan; Fayard, Elba

    2015-01-01

    To examine the effects of oral sucrose on procedural pain, and on biochemical markers of adenosine triphosphate utilization and oxidative stress in preterm neonates with mild to moderate respiratory distress. Preterm neonates with a clinically required heel lance that met study criteria (n = 49) were randomized into three groups: (1) control (n = 24), (2) heel lance treated with placebo and non-nutritive sucking (n = 15) and (3) heel lance treated with sucrose and non-nutritive sucking (n = 10). Plasma markers of adenosine triphosphate degradation (hypoxanthine, xanthine and uric acid) and oxidative stress (allantoin) were measured before and after the heel lance. Pain was measured using the Premature Infant Pain Profile. Data were analyzed using repeated measures analysis of variance, chi-square and one-way analysis of variance. We found that in preterm neonates who were intubated and/or were receiving ⩾30% FiO2, a single dose of oral sucrose given before a heel lance significantly increased markers of adenosine triphosphate use. We found that oral sucrose enhanced adenosine triphosphate use in neonates who were intubated and/or were receiving ⩾30% FiO2. Although oral sucrose decreased pain scores, our data suggest that it also increased energy use as evidenced by increased plasma markers of adenosine triphosphate utilization. These effects of sucrose, specifically the fructose component, on adenosine triphosphate metabolism warrant further investigation.

  6. 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 (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7040...

  7. Synthesis of high specific activity tritium labelled [2-3H]-adenosine-5'-triphosphate

    International Nuclear Information System (INIS)

    Jaiswal, D.K.; Morimoto, H.; Trump, E.L.; Williams, P.G.; Wemmer, D.E.

    1996-01-01

    A procedure for high level tritium labelling at the C2-H position of adenosine 5'-triphosphate ([2- 3 H]-ATP, 1), based on the tritiodehalogenation reaction of 2-bromoadenosine 5'-triphosphate (2) has been elaborated. This precursor was prepared in a six-step synthesis from guanosine. The tritiodehalogenation of (2) for three hours over palladium oxide in phosphate buffer yielded tritium labelled ATP with high specific activity, in good chemical yield. (author)

  8. 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

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

    International Nuclear Information System (INIS)

    Hung, Szu-Ying; Shih, Ya-Chen; Tseng, Wei-Lung

    2015-01-01

    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

  10. Microcontroller-assisted compensation of adenosine triphosphate levels: instrument and method development.

    Science.gov (United States)

    Hu, Jie-Bi; Chen, Ting-Ru; Chen, Yu-Chie; Urban, Pawel L

    2015-01-30

    In order to ascertain optimum conditions for biocatalytic processes carried out in vitro, we have designed a bio-opto-electronic system which ensures real-time compensation for depletion of adenosine triphosphate (ATP) in reactions involving transfer of phosphate groups. The system covers ATP concentration range of 2-48 μM. The report demonstrates feasibility of the device operation using apyrase as the ATP-depleting enzyme.

  11. Synthesis of adenosine triphosphate tritiated in position 2 and 8

    International Nuclear Information System (INIS)

    Cossery, Jean-Michel

    1986-01-01

    Adenosine triphosphate or ATP is an important molecule present at the cellular level in many fundamental biochemical mechanism, and the study of its metabolism is therefore of particular interest. In this thesis for pharmacy graduation, the author first describes the different steps of synthesis and purification leading to chloride-2-ATP, a precursor of the final tritiated molecule. Then, the author explains the tritiation of this molecule to obtain an ATP tritiated in position 2 and in position 8 [fr

  12. Spectral studies of lanthanide-nucleic acid component interaction: complexes of adenine, adenosine, adenosine 5'-mono-, adenosine 5'-di- and adenosine 5' tri-phosphates with praseodymium(III)

    International Nuclear Information System (INIS)

    Joseph, George; Anjaiah, K.; Misra, S.N.

    1990-01-01

    The interactions of adenine, adenosine, adenosine 5'-mono-, adenosine 5'-di-and adenosine 5'-tri-phosphates with praseodymium(III) have been studied in different stoichiometries and at varying hydrogen ion concentrations by absorption spectral studies. The sharp bands in the spectra have been individually analysed by Gaussian curve analysis, and various spectral parameters have been computed using partial and multiple regression methods on an HP-1000/45 computer. The changes in and the magnitudes of these parameters have been correlated with the degrees of outer- and inner-sphere coordination around praseodymium(III). Crystalline complexes of the type: Pr(nucleotide) 2 (H 2 O) 2 (where nucleotide = AMP, ADP and ATP) have been characterized on the basis of analytical, IR and 1 H NMR spectral data. These studies indicate that the binding of the nucleotide is through phosphoric oxygen. These complexes in aqueous medium show significant ionization which supports the observed weak 4f-4f bands, lower values of nephelauxetic effect and the parameters derived from coulombic and spin-orbit interactions. (author). 3 t abs., 28 refs

  13. In vivo effects of adenosine 5´-triphosphate on rat preneoplastic liver

    Directory of Open Access Journals (Sweden)

    Ana V. Frontini

    2011-04-01

    Full Text Available The utilization of adenosine 5´-triphosphate (ATP infusions to inhibit the growth of some human and animals tumors was based on the anticancer activity observed in in vitro and in vivo experiments, but contradictory results make the use of ATP in clinical practice rather controversial. Moreover, there is no literature regarding the use of ATP infusions to treat hepatocarcinomas. The purpose of this study was to investigate whether ATP prevents in vivo oncogenesis in very-early-stage cancer cells in a well characterized two-stage model of hepatocarcinogenesis in the rat. As we could not preclude the possible effect due to the intrinsic properties of adenosine, a known tumorigenic product of ATP hydrolysis, the effect of the administration of adenosine was also studied. Animals were divided in groups: rats submitted to the two stage preneoplasia initiation/promotion model of hepatocarcinogenesis, rats treated with intraperitoneal ATP or adenosine during the two phases of the model and appropriate control groups. The number and volume of preneoplastic foci per liver identified by the expression of glutathione S-transferase placental type and the number of proliferating nuclear antigen positive cells significantly increased in ATP and adenosine treated groups. Taken together, these results indicate that in this preneoplastic liver model, ATP as well as adenosine disturb the balance between apoptosis and proliferation contributing to malignant transformation.

  14. Visual and Plasmon Resonance Absorption Sensor for Adenosine Triphosphate Based on the High Affinity between Phosphate and Zr(IV).

    Science.gov (United States)

    Qi, Wenjing; Liu, Zhongyuan; Zhang, Wei; Halawa, Mohamed Ibrahim; Xu, Guobao

    2016-10-12

    Zr(IV) can form phosphate and Zr(IV) (-PO₃ 2- -Zr 4+ -) complex owing to the high affinity between Zr(IV) with phosphate. Zr(IV) can induce the aggregation of gold nanoparticles (AuNPs), while adenosine triphosphate(ATP) can prevent Zr(IV)-induced aggregation of AuNPs. Herein, a visual and plasmon resonance absorption (PRA)sensor for ATP have been developed using AuNPs based on the high affinity between Zr(IV)with ATP. AuNPs get aggregated in the presence of certain concentrations of Zr(IV). After the addition of ATP, ATP reacts with Zr(IV) and prevents AuNPs from aggregation, enabling the detection of ATP. Because of the fast interaction of ATP with Zr(IV), ATP can be detected with a detection limit of 0.5 μM within 2 min by the naked eye. Moreover, ATP can be detected by the PRA technique with higher sensitivity. The A 520nm / A 650nm values in PRA spectra increase linearly with the concentrations of ATP from 0.1 μM to 15 μM (r = 0.9945) with a detection limit of 28 nM. The proposed visual and PRA sensor exhibit good selectivity against adenosine, adenosine monophosphate, guanosine triphosphate, cytidine triphosphate and uridine triphosphate. The recoveries for the analysis of ATP in synthetic samples range from 95.3% to 102.0%. Therefore, the proposed novel sensor for ATP is promising for real-time or on-site detection of ATP.

  15. Visual and Plasmon Resonance Absorption Sensor for Adenosine Triphosphate Based on the High Affinity between Phosphate and Zr(IV

    Directory of Open Access Journals (Sweden)

    Wenjing Qi

    2016-10-01

    Full Text Available Zr(IV can form phosphate and Zr(IV (–PO32−–Zr4+– complex owing to the high affinity between Zr(IV with phosphate. Zr(IV can induce the aggregation of gold nanoparticles (AuNPs, while adenosine triphosphate(ATP can prevent Zr(IV-induced aggregation of AuNPs. Herein, a visual and plasmon resonance absorption (PRAsensor for ATP have been developed using AuNPs based on the high affinity between Zr(IVwith ATP. AuNPs get aggregated in the presence of certain concentrations of Zr(IV. After the addition of ATP, ATP reacts with Zr(IV and prevents AuNPs from aggregation, enabling the detection of ATP. Because of the fast interaction of ATP with Zr(IV, ATP can be detected with a detection limit of 0.5 μM within 2 min by the naked eye. Moreover, ATP can be detected by the PRA technique with higher sensitivity. The A520nm/A650nm values in PRA spectra increase linearly with the concentrations of ATP from 0.1 μM to 15 μM (r = 0.9945 with a detection limit of 28 nM. The proposed visual and PRA sensor exhibit good selectivity against adenosine, adenosine monophosphate, guanosine triphosphate, cytidine triphosphate and uridine triphosphate. The recoveries for the analysis of ATP in synthetic samples range from 95.3% to 102.0%. Therefore, the proposed novel sensor for ATP is promising for real-time or on-site detection of ATP.

  16. 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%.

  17. 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

    2015-12-07

    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 × 10(6) 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%.

  18. Extracellular adenosine 5'-triphosphate concentrations changes in rat spinal cord associated with the activation of urinary bladder afferents. A microdialysis study.

    Science.gov (United States)

    Rocha, Jeová Nina

    2016-01-01

    To determine adenosine 5'-triphosphate levels in the interstice of spinal cord L6-S1 segment, under basal conditions or during mechanical and chemical activation of urinary bladder afferents. A microdialysis probe was transversally implanted in the dorsal half of spinal cord L6-S1 segment in female rats. Microdialysate was collected at 15 minutes intervals during 135 minutes, in anesthetized animals. Adenosine 5'-triphosphate concentrations were determined with a bioluminescent assay. In one group of animals (n=7) microdialysate samples were obtained with an empty bladder during a 10-minutes bladder distension to 20 or 40cmH2O with either saline, saline with acetic acid or saline with capsaicin. In another group of animals (n=6) bladder distention was performed and the microdialysis solution contained the ectonucleotidase inhibitor ARL 67156. Basal extracellular adenosine triphosphate levels were 110.9±35.34fmol/15 minutes, (mean±SEM, n=13), and bladder distention was associated with a significant increase in adenosine 5'-triphosphate levels which was not observed after bladder distention with saline solution containing capsaicin (10µM). Microdialysis with solution containing ARL 67156 (1mM) was associated with significantly higher extracellular adenosine 5'-triphosphate levels and no further increase in adenosine 5'-triphosphate was observed during bladder distension. Adenosine 5'-triphosphate was present in the interstice of L6-S1 spinal cord segments, was degraded by ectonucleotidase, and its concentration increased following the activation of bladder mechanosensitive but not of the chemosensitive afferents fibers. Adenosine 5'-triphosphate may originate either from the central endings of bladder mechanosensitive primary afferent neurons, or most likely from intrinsic spinal neurons, or glial cells and its release appears to be modulated by capsaicin activated bladder primary afferent or by adenosine 5'-triphosphate itself. Determinar as concentra

  19. Mechanism of adenylate kinase. Dose adenosine 5'-triphosphate bind to the adenosine 5'-monophosphate site

    Energy Technology Data Exchange (ETDEWEB)

    Shyy, Y.J.; Tian, G.; Tsai, M.D.

    1987-10-06

    Although the subtrate binding properties of adenylate kinase (AK) have been studied extensively by various biochemical and biophysical techniques, it remains controversial whether uncomplexed adenosine 5'-triphosphate (ATP) binds to the adenosine 5'-monophosphate (AMP) site of AK. The authors present two sets of experiments which argue against binding of ATP to the AMP site. (a) /sup 31/P nuclear magnetic resonance titration of ATP with AK indicated a 1:1 stoichiometry on the basis of changes in coupling constants and line widths. This ruled out binding of ATP to both sites. (b) ATP and MgATP were found to behave similarly by protecting AK from spontaneous inactivation while AMP showed only a small degree of protection. Such inactivation could also be protected or reversed by dithioerythritol and is most likely due to oxidation of sulfhydryl groups, one of which (cysteine-25) is located near the MgATP site. The results support binding of ATP to the MgATP site predominantly, instead of the AMP site, in the absence of Mg/sup 2 +/.

  20. Effects of adenosine triphosphate concentration on motor force regulation during skeletal muscle contraction

    Science.gov (United States)

    Wei, J.; Dong, C.; Chen, B.

    2017-04-01

    We employ a mechanical model of sarcomere to quantitatively investigate how adenosine triphosphate (ATP) concentration affects motor force regulation during skeletal muscle contraction. Our simulation indicates that there can be negative cross-bridges resisting contraction within the sarcomere and higher ATP concentration would decrease the resistance force from negative cross-bridges by promoting their timely detachment. It is revealed that the motor force is well regulated only when ATP concentration is above a certain level. These predictions may provide insights into the role of ATP in regulating coordination among multiple motors.

  1. 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.

  2. Adenosine triphosphate levels during anaphylactic histamine release in rat mast cells in vitro. Effects of glycolytic and respiratory inhibitors

    DEFF Research Database (Denmark)

    Johansen, Torben

    1979-01-01

    The adenosine triphosphate (ATP) content of rat mast cells was studied during and after anaphylactic histamine release. The almost identical time course of ATP decrease from mast cells treated with either glycolytic or respiratory inhibitors supports the view that the ATP depletion was largely re...

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

    Energy Technology Data Exchange (ETDEWEB)

    Pai, Moon Sun; Park, Chan H.; Yoon, Seok Nam; Kim, Won; Kim, Han Soo [College of Medicine, Ajou Univ., Suwon (Korea, Republic of)

    1998-08-01

    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.

  4. 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)

    Pai, Moon Sun; Park, Chan H.; Yoon, Seok Nam; Kim, Won; Kim, Han Soo

    1998-01-01

    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

  5. Mitochondrially-Encoded Adenosine Triphosphate Synthase 6 Gene Haplotype Variation among World Population during 2003-2013

    OpenAIRE

    Steven Steven; Yoni F Syukriani; Julius B Dewanto

    2016-01-01

    Background: Adaptation and natural selection serve as an important part of evolution. Adaptation in molecular level can lead to genetic drift which causes mutation of genetic material; one of which is polymorphism of mitochondrial DNA (mtDNA). The aim of this study is to verify the polymorphism of mitochondrially-encoded Adenosine Triphosphate synthase6gene (MT-ATP6) as one of mtDNA building blocks among tropic, sub-tropic, and polar areas. Methods: This descriptive quantitative research used...

  6. 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

  7. Peculiarities of different-ligand complexing of rare earths with nitrilotriacetate and adenosine-5'-triphosphate according to the mathematical simulation data

    International Nuclear Information System (INIS)

    Svetlova, I.E.; Dobrynina, N.A.; Smirnova, N.S.; Martynenko, L.I.; Evseev, A.M.

    1988-01-01

    By the method of pH-metric titration using mathematical simulation different-ligand complexing of rare earths with nitrilotriacetate and adenosine-5'-triphosphate is studied. It is shown that the ligands interact with the formation of protonated associates. The composition of different complexes is determined, their stability constants are calculated, their existence regions are found

  8. Artificial oxygen carrier with pharmacologic actions of adenosine-5'-triphosphate, adenosine, and reduced glutathione formulated to treat an array of medical conditions.

    Science.gov (United States)

    Simoni, Jan; Simoni, Grace; Moeller, John F; Feola, Mario; Wesson, Donald E

    2014-08-01

    Effective artificial oxygen carriers may offer a solution to tackling current transfusion medicine challenges such as blood shortages, red blood cell storage lesions, and transmission of emerging pathogens. These products, could provide additional therapeutic benefits besides oxygen delivery for an array of medical conditions. To meet these needs, we developed a hemoglobin (Hb)-based oxygen carrier, HemoTech, which utilizes the concept of pharmacologic cross-linking. It consists of purified bovine Hb cross-linked intramolecularly with open ring adenosine-5'-triphosphate (ATP) and intermolecularly with open ring adenosine, and conjugated with reduced glutathione (GSH). In this composition, ATP prevents Hb dimerization, and adenosine promotes formation of Hb polymers as well as counteracts the vasoconstrictive and pro-inflammatory properties of Hb via stimulation of adenosine receptors. ATP also serves as a regulator of vascular tone through activation of purinergic receptors. GSH blocks Hb's extravasation and glomerular filtration by lowering the isoelectric point, as well as shields heme from nitric oxide and reactive oxygen species. HemoTech and its manufacturing technology have been broadly tested, including viral and prion clearance validation studies and various nonclinical pharmacology, toxicology, genotoxicity, and efficacy tests. The clinical proof-of-concept was carried out in sickle cell anemia subjects. The preclinical and clinical studies indicate that HemoTech works as a physiologic oxygen carrier and has efficacy in treating: (i) acute blood loss anemia by providing a temporary oxygen bridge while stimulating an endogenous erythropoietic response; (ii) sickle cell disease by counteracting vaso-occlusive/inflammatory episodes and anemia; and (iii) ischemic vascular diseases particularly thrombotic and restenotic events. The pharmacologic cross-linking of Hb with ATP, adenosine, and GSH showed usefulness in designing an artificial oxygen carrier for

  9. A G-quadruplex-based Label-free Fluorometric Aptasensor for Adenosine Triphosphate Detection.

    Science.gov (United States)

    Li, Li Juan; Tian, Xue; Kong, Xiang Juan; Chu, Xia

    2015-01-01

    A G-quadruplex-based, label-free fluorescence assay was demonstrated for the detection of adenosine triphosphate (ATP). A double-stranded DNA (dsDNA), hybridized by ATP-aptamer and its complementary sequence, was employed as a substrate for ATP binding. SYBR Green I (SG I) was a fluorescent probe and exonuclease III (Exo III) was a nuclease to digest the dsDNA. Consequently, in the absence of ATP, the dsDNA was inset with SG I and was digested by Exo III, resulting in a low background signal. In the presence of ATP, the aptamer in dsDNA folded into a G-quadruplex structure that resisted the digestion of Exo III. SG I was inserted into the structure, showing high fluorescence. Owing to a decrease of the background noise, a high signal-to-noise ratio could be obtained. This sensor can detect ATP with a concentration ranging from 50 μM to 5 mM, and possesses a capacity for the sensitive determination of other targets.

  10. Nitrogen and phosphorus co-doped graphene quantum dots: synthesis from adenosine triphosphate, optical properties, and cellular imaging.

    Science.gov (United States)

    Ananthanarayanan, Arundithi; Wang, Yue; Routh, Parimal; Sk, Mahasin Alam; Than, Aung; Lin, Ming; Zhang, Jie; Chen, Jie; Sun, Handong; Chen, Peng

    2015-05-07

    Graphene quantum dots (GQDs) are emerging zero-dimensional materials promising a wide spectrum of applications, particularly, as superior fluorescent reporters for bio-imaging and optical sensing. Heteroatom doping can endow GQDs with new or improved photoluminescence properties. Here, we demonstrate a simple strategy for the synthesis of nitrogen and phosphorus co-doped GQDs from a single biomolecule precursor (adenosine triphosphate - ATP). Such ATP-GQDs exhibit high fluorescence quantum yield, strong two-photon upconversion, small molecular weight, high photostability, and good biocompatibility. Furthermore, transferrin conjugated ATP-GQDs have been used for imaging and real-time tracking of transferrin receptors in live cells.

  11. On the structure of thorium and americium adenosine triphosphate complexes

    International Nuclear Information System (INIS)

    Mostapha, Sarah; Berton, Laurence; Boubals, Nathalie; Zorz, Nicole; Charbonnel, Marie-Christine; Fontaine-Vive, Fabien; Den Auwer, Christophe; Solari, Pier Lorenzo

    2014-01-01

    The actinides are chemical poisons and radiological hazards. One challenge to better appraise their toxicity and develop countermeasures in case of exposure of living organisms is to better assess pathways of contamination. Because of the high chemical affinity of those actinide elements for phosphate groups and the ubiquity of such chemical functions in biochemistry, nucleotides and in particular adenosine triphosphate nucleotide (ATP) may be considered critical target building blocks for actinides. Combinations of spectroscopic techniques (Fourier transformed Infra Red [FTIR], Electro-spray Ionization Mass Spectrometry [ESI-MS], and Extended X-ray Absorption Fine Structure [EXAFS]) with quantum chemical calculations have been implemented in order to assess the actinides coordination arrangement with ATP. We describe and compare herein the interaction of ATP with thorium and americium; thorium(IV) as a representative of actinide(IV) like plutonium(IV) and americium(III) as a representative of all heavier actinides. In the case of thorium, an insoluble complex is readily formed. In the case of americium, a behavior identical to that described previously for lutetium has been observed with insoluble and soluble complexes. The comparative study of ATP complexation with Th(IV) and Am(III) shows their ability to form insoluble complexes for which a structural model has been proposed by analogy with previously described Lu(III) complexes. (authors)

  12. On the structure of thorium and americium adenosine triphosphate complexes.

    Science.gov (United States)

    Mostapha, Sarah; Fontaine-Vive, Fabien; Berthon, Laurence; Boubals, Nathalie; Zorz, Nicole; Solari, Pier Lorenzo; Charbonnel, Marie Christine; Den Auwer, Christophe

    2014-11-01

    The actinides are chemical poisons and radiological hazards. One challenge to better appraise their toxicity and develop countermeasures in case of exposure of living organisms is to better assess pathways of contamination. Because of the high chemical affinity of those actinide elements for phosphate groups and the ubiquity of such chemical functions in biochemistry, nucleotides and in particular adenosine triphosphate nucleotide (ATP) may be considered critical target building blocks for actinides. Combinations of spectroscopic techniques (Fourier transformed Infra Red [FTIR], Electrospray Ionization Mass Spectrometry [ESI-MS], and Extended X-ray Absorption Fine Structure [EXAFS]) with quantum chemical calculations have been implemented in order to assess the actinides coordination arrangement with ATP. We describe and compare herein the interaction of ATP with thorium and americium; thorium(IV) as a representative of actinide(IV) like plutonium(IV) and americium(III) as a representative of all heavier actinides. In the case of thorium, an insoluble complex is readily formed. In the case of americium, a behavior identical to that described previously for lutetium has been observed with insoluble and soluble complexes. The comparative study of ATP complexation with Th(IV) and Am(III) shows their ability to form insoluble complexes for which a structural model has been proposed by analogy with previously described Lu(III) complexes.

  13. The effect of experimental gastric dilatation-volvulus on adenosine triphosphate content and conductance of the canine gastric and jejunal mucosa

    OpenAIRE

    Peycke, Laura E.; Hosgood, Giselle; Davidson, Jacqueline R.; Tetens, Joanne; Taylor, H. Wayne

    2005-01-01

    The objective of this study was to determine if experimental gastric dilatation volvulus (GDV) would decrease adenosine triphosphate (ATP) concentration and increase membrane conductance of the canine gastric and jejunal mucosa. Male dogs (n = 15) weighing between 20 and 30 kg were used. Dogs were randomly assigned to 1 of 3 equal groups: Group 1 was control, group 2 was GDV, and group 3 was ischemia. All dogs were anesthetized for 210 min. Group 1 had no manipulation. Group 2 had GDV experim...

  14. Visual and Plasmon Resonance Absorption Sensor for Adenosine Triphosphate Based on the High Affinity between Phosphate and Zr(IV)

    OpenAIRE

    Qi, Wenjing; Liu, Zhongyuan; Zhang, Wei; Halawa, Mohamed Ibrahim; Xu, Guobao

    2016-01-01

    Zr(IV) can form phosphate and Zr(IV) (?PO3 2??Zr4+?) complex owing to the high affinity between Zr(IV) with phosphate. Zr(IV) can induce the aggregation of gold nanoparticles (AuNPs), while adenosine triphosphate(ATP) can prevent Zr(IV)-induced aggregation of AuNPs. Herein, a visual and plasmon resonance absorption (PRA)sensor for ATP have been developed using AuNPs based on the high affinity between Zr(IV)with ATP. AuNPs get aggregated in the presence of certain concentrations of Zr(IV). Aft...

  15. A novel conductometric biosensor based on hexokinase for determination of adenosine triphosphate.

    Science.gov (United States)

    Kucherenko, I S; Kucherenko, D Yu; Soldatkin, O O; Lagarde, F; Dzyadevych, S V; Soldatkin, A P

    2016-04-01

    The paper presents a simple and inexpensive reusable biosensor for determination of the concentration of adenosine-5'-triphosphate (ATP) in aqueous samples. The biosensor is based on a conductometric transducer which contains two pairs of gold interdigitated electrodes. An enzyme hexokinase was immobilized onto one pair of electrodes, and bovine serum albumin-onto another pair (thus, a differential mode of measurement was used). Conditions of hexokinase immobilization on the transducer by cross-linking via glutaraldehyde were optimized. Influence of experimental conditions (concentration of magnesium ions, ionic strength and concentration of the working buffer) on the biosensor work was studied. The reproducibility of biosensor responses and operational stability of the biosensor were checked during one week. Dry storage at -18 °C was shown to be the best conditions to store the biosensor. The biosensor was successfully applied for measurements of ATP concentration in pharmaceutical samples. The proposed biosensor may be used in future for determination of ATP and/or glucose in water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Damage to adenosine-triphosphate induced by monochromatic X rays around the K shell absorption edge of phosphorus

    International Nuclear Information System (INIS)

    Watanabe, Ritsuko; Ishikawa, Mitsuo; Takakura, Kaoru; Kobayashi, Katsumi

    1992-01-01

    Adenosine-triphosphate (ATP) is well known to have an important role in the energy metabolism in biological systems. The purpose of this study is to clarify the radiation effects on ATP specific to inner shell ionization. ATP, in concentrated aqueous solution, was irradiated with monochromatic X rays having energies of the resonance absorption peak of the phosphorus K shell, 2.153 keV, and slightly below and above the peak, 2.145 keV and 2.160 keV, selected from synchrotron radiation. Adenine, Adenosine 5'monophosphate (5'AMP) and Adenosine 5'diphosphate (5'ADP) were obtained as radioproducts by the method of high performance liquid chromatography (HPLC). G values of these products were calculated on the basis of the absorbed energy. When the ATP solution of 0.282 mol/l was irradiated with 2.160 keV X rays which can ionize the K shell of phosphorus, G values of Adenine, 5'AMP and 5'ADP were estimated to be 1.4, 0.40 and 0.46, respectively. These values were respectively 1.3, 2.9 and 3.8 times higher than those obtained upon irradiation with 2.146 keV X rays which cannot ionize the K shell of phosphorus. These energy dependent enhancements may reflect the difference in energy absorption processes, especially the Auger cascade in phosphorus may be suspected to play an important role in these enhancements

  17. Rapid photolytic release of adenosine 5'-triphosphate from a protected analogue: utilization by the Na:K pump of human red blood cell ghosts

    International Nuclear Information System (INIS)

    Kaplan, J.H.; Forbush, B. III; Hoffman, J.F.

    1978-01-01

    2-Nitrobenzyl phosphate and 1-(2-nitro)phenylethyl phosphate have been synthesized and demonstrated to be suitable as photolabile sources of inorganic phosphate. The same protecting groups were attached to the terminal phosphate of adenosine 5'-triphosphate. These caged ATP compounds released adenosine 5'-triphosphate on illumination at 340 nm in aqueous solution and P 3 -1-(2-nitro)phenylethyl-ATP gave about a 70 percent yield in under 30 s. The unphotolyzed caged ATP was neither a substrate nor inhibitor of purified renal Na,K-ATPase (EC 3.61.3). Following photolysis in the presence of the enzyme, the liberated ATP was hydrolyzed but at an inhibited rate. The photo-dependent inhibition could be eliminated by prior addition of glutathione or bisulfite to the irradiated solution. Caged ATP was incorporated into resealed human erythrocyte ghosts prepared from red blood cells depleted of internal energy stores. While the NA : K pump was unable to use incorporated caged ATP as a substrate, the ATP liberated by photolysis activated the pump as evidenced by measurements of K-dependent, ouabain-sensitive Na efflux. Thus the caged ATP can be used as a stable source of ATP unmetabolizable by intracellular ATPases until the ATP is released following photolytic irradiation

  18. Adenosine triphosphate-guided pulmonary vein isolation for atrial fibrillation: the UNmasking Dormant Electrical Reconduction by Adenosine TriPhosphate (UNDER-ATP) trial.

    Science.gov (United States)

    Kobori, Atsushi; Shizuta, Satoshi; Inoue, Koichi; Kaitani, Kazuaki; Morimoto, Takeshi; Nakazawa, Yuko; Ozawa, Tomoya; Kurotobi, Toshiya; Morishima, Itsuro; Miura, Fumiharu; Watanabe, Tetsuya; Masuda, Masaharu; Naito, Masaki; Fujimoto, Hajime; Nishida, Taku; Furukawa, Yoshio; Shirayama, Takeshi; Tanaka, Mariko; Okajima, Katsunori; Yao, Takenori; Egami, Yasuyuki; Satomi, Kazuhiro; Noda, Takashi; Miyamoto, Koji; Haruna, Tetsuya; Kawaji, Tetsuma; Yoshizawa, Takashi; Toyota, Toshiaki; Yahata, Mitsuhiko; Nakai, Kentaro; Sugiyama, Hiroaki; Higashi, Yukei; Ito, Makoto; Horie, Minoru; Kusano, Kengo F; Shimizu, Wataru; Kamakura, Shiro; Kimura, Takeshi

    2015-12-07

    Most of recurrent atrial tachyarrhythmias after pulmonary vein isolation (PVI) for atrial fibrillation (AF) are due to reconnection of PVs. The aim of the present study was to evaluate whether elimination of adenosine triphosphate (ATP)-induced dormant PV conduction by additional energy applications during the first ablation procedure could reduce the incidence of recurrent atrial tachyarrhythmias. We randomly assigned 2113 patients with paroxysmal, persistent, or long-lasting AF to either ATP-guided PVI (1112 patients) or conventional PVI (1001 patients). The primary endpoint was recurrent atrial tachyarrhythmias lasting for >30 s or those requiring repeat ablation, hospital admission, or usage of Vaughan Williams class I or III antiarrhythmic drugs at 1 year with the blanking period of 90 days post ablation. Among patients assigned to ATP-guided PVI, 0.4 mg/kg body weight of ATP provoked dormant PV conduction in 307 patients (27.6%). Additional radiofrequency energy applications successfully eliminated dormant conduction in 302 patients (98.4%). At 1 year, 68.7% of patients in the ATP-guided PVI group and 67.1% of patients in the conventional PVI group were free from the primary endpoint, with no significant difference (adjusted hazard ratio [HR] 0.89; 95% confidence interval [CI] 0.74-1.09; P = 0.25). The results were consistent across all the prespecified subgroups. Also, there was no significant difference in the 1-year event-free rates from repeat ablation for any atrial tachyarrhythmia between the groups (adjusted HR 0.83; 95% CI 0.65-1.08; P = 0.16). In the catheter ablation for AF, we found no significant reduction in the 1-year incidence of recurrent atrial tachyarrhythmias by ATP-guided PVI compared with conventional PVI. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

  19. Direct growth of graphene on quartz substrates for label-free detection of adenosine triphosphate

    International Nuclear Information System (INIS)

    Xu, Shicai; Man, Baoyuan; Jiang, Shouzhen; Yue, Weiwei; Yang, Cheng; Liu, Mei; Chen, Chuansong; Zhang, Chao

    2014-01-01

    We demonstrate that continuous, uniform graphene films can be directly synthesized on quartz substrates using a two-temperature-zone chemical vapor deposition system and that their layers can be controlled by adjusting the precursor partial pressure. Raman spectroscopy and transmission electron microscopy confirm the formation of monolayer graphene with a grain size of ∼100 nm. Hall measurements show a room-temperature carrier mobility above 1500 cm 2  V −1  s −1 . The optical transmittance and conductance of the graphene films are comparable to those of transferred metal-catalyzed graphene. The method avoids the complicated and skilled post-growth transfer process and allows the graphene to be directly incorporated into a fully functional biosensor for label-free detection of adenosine triphosphate (ATP). This device shows a fast response time of a few milliseconds and achieves a high sensitivity to ATP molecules over a very wide range from 0.002 to 5 mM. (paper)

  20. Direct growth of graphene on quartz substrates for label-free detection of adenosine triphosphate.

    Science.gov (United States)

    Xu, Shicai; Man, Baoyuan; Jiang, Shouzhen; Yue, Weiwei; Yang, Cheng; Liu, Mei; Chen, Chuansong; Zhang, Chao

    2014-04-25

    We demonstrate that continuous, uniform graphene films can be directly synthesized on quartz substrates using a two-temperature-zone chemical vapor deposition system and that their layers can be controlled by adjusting the precursor partial pressure. Raman spectroscopy and transmission electron microscopy confirm the formation of monolayer graphene with a grain size of ∼100 nm. Hall measurements show a room-temperature carrier mobility above 1500 cm2 V(-1) s(-1). The optical transmittance and conductance of the graphene films are comparable to those of transferred metal-catalyzed graphene. The method avoids the complicated and skilled post-growth transfer process and allows the graphene to be directly incorporated into a fully functional biosensor for label-free detection of adenosine triphosphate (ATP). This device shows a fast response time of a few milliseconds and achieves a high sensitivity to ATP molecules over a very wide range from 0.002 to 5 mM.

  1. Application of firefly luciferase assay for adenosine triphosphate (ATP) to antimicrobial drug sensitivity testing

    Science.gov (United States)

    Picciolo, G. L.; Tuttle, S. A.; Schrock, C. G.; Deming, J. W.; Barza, M. J.; Wienstein, L.; Chappelle, E. W.

    1977-01-01

    The development of a rapid method for determining microbial susceptibilities to antibiotics using the firefly luciferase assay for adenosine triphosphate (ATP) is documented. The reduction of bacterial ATP by an antimicrobial agent was determined to be a valid measure of drug effect in most cases. The effect of 12 antibiotics on 8 different bacterial species gave a 94 percent correlation with the standard Kirby-Buer-Agar disc diffusion method. A 93 percent correlation was obtained when the ATP assay method was applied directly to 50 urine specimens from patients with urinary tract infections. Urine samples were centrifuged first to that bacterial pellets could be suspended in broth. No primary isolation or subculturing was required. Mixed cultures in which one species was predominant gave accurate results for the most abundant organism. Since the method is based on an increase in bacterial ATP with time, the presence of leukocytes did not interfere with the interpretation of results. Both the incubation procedure and the ATP assays are compatible with automation.

  2. Determination of ATP as a fluorescence probe with europium(III)-doxycycline.

    Science.gov (United States)

    Hou, Faju; Wang, Xiaolei; Jiang, Chongqiu

    2005-03-01

    A new spectrofluorimetric method has been developed for the determination of adenosine disodium triphosphate (ATP). We studied the interactions between the doxycycline (DC)-Eu3+ complex and adenosine disodium triphosphate (ATP) by using UV-visible absorption and fluorescence spectra. Using doxycycline (DC)-Eu3+ as a fluorescence probe, under the optimum conditions, ATP could remarkably enhance the fluorescence intensity of the DC-Eu3+ complex at lambda = 612 nm. The enhanced fluorescence intensity of the Eu3+ ion was in proportion to the concentration of ATP. The optimum conditions for the determination of ATP were also investigated. The linear ranges for ATP were 1.00 x 10(-7) - 2.00 x 10(-6) mol L(-1) with detection limits of 4.07 x 10(-8) mol L(-1). This method is simple, practical and relatively free of interference from coexisting substances, and can be successfully applied to the determination of ATP in samples. The mechanism of fluorescence enhancement between the doxycycline (DC)-Eu3+ complex and ATP was also studied.

  3. A label-free fluorescent adenosine triphosphate biosensor via overhanging aptamer-triggered enzyme protection and target recycling amplification.

    Science.gov (United States)

    Wang, Zhaoyin; Zhao, Jian; Dai, Zhihui

    2016-06-20

    Herein, a label-free fluorescent adenosine triphosphate (ATP) aptasensor is fabricated with a DNA hairpin and an overhanging aptamer. In the presence of ATP, the overhanging sequences of the aptamer may form preferred substrates of exo III, and thus trigger the enzyme-assisted amplification, which results in the release of G-rich sequences. Free G-rich sequences subsequently generate an enhanced flourescent signal by binding with thioflavin T. However, if ATP is absent, the overhanging sequence can induce steric hindrance and protect the DNA hairpin against the digestion of exo III, significantly reducing the noise of this biosensor. Accordingly, the signal-to-noise ratio of the sensing system is greatly improved, which ensures the desirable analytical performance of the proposed aptasensor both in pure samples and real samples.

  4. 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.

  5. Effects of caffeine on fractional flow reserve values measured using intravenous adenosine triphosphate.

    Science.gov (United States)

    Nakayama, Masafumi; Chikamori, Taishiro; Uchiyama, Takashi; Kimura, Yo; Hijikata, Nobuhiro; Ito, Ryosuke; Yuhara, Mikio; Sato, Hideaki; Kobori, Yuichi; Yamashina, Akira

    2018-04-01

    We investigated the effects of caffeine intake on fractional flow reserve (FFR) values measured using intravenous adenosine triphosphate (ATP) before cardiac catheterization. Caffeine is a competitive antagonist for adenosine receptors; however, it is unclear whether this antagonism affects FFR values. Patients were evenly randomized into 2 groups preceding the FFR study. In the caffeine group (n = 15), participants were given coffee containing 222 mg of caffeine 2 h before the catheterization. In the non-caffeine group (n = 15), participants were instructed not to take any caffeine-containing drinks or foods for at least 12 h before the catheterization. FFR was performed in patients with more than intermediate coronary stenosis using the intravenous infusion of ATP at 140 μg/kg/min (normal dose) and 170 μg/kg/min (high dose), and the intracoronary infusion of papaverine. FFR was followed for 30 s after maximal hyperemia. In the non-caffeine group, the FFR values measured with ATP infusion were not significantly different from those measured with papaverine infusion. However, in the caffeine group, the FFR values were significantly higher after ATP infusion than after papaverine infusion (P = 0.002 and P = 0.007, at normal and high dose ATP vs. papaverine, respectively). FFR values with ATP infusion were significantly increased 30 s after maximal hyperemia (P = 0.001 and P < 0.001 for normal and high dose ATP, respectively). The stability of the FFR values using papaverine showed no significant difference between the 2 groups. Caffeine intake before the FFR study affected FFR values and their stability. These effects could not be reversed by an increased ATP dose.

  6. Enzymatic properties of Staphylococcus aureus adenosine synthase (AdsA)

    Science.gov (United States)

    2011-01-01

    Background Staphylococcus aureus is a human pathogen that produces extracellular adenosine to evade clearance by the host immune system, an activity attributed to the 5'-nucleotidase activity of adenosine synthase (AdsA). In mammals, conversion of adenosine triphosphate to adenosine is catalyzed in a two-step process: ecto-nucleoside triphosphate diphosphohydrolases (ecto-NTDPases) hydrolyze ATP and ADP to AMP, whereas 5'-nucleotidases hydrolyze AMP to adenosine. NTPDases harbor apyrase conserved regions (ACRs) that are critical for activity. Results NTPDase ACR motifs are absent in AdsA, yet we report here that recombinant AdsA hydrolyzes ADP and ATP in addition to AMP. Competition assays suggest that hydrolysis occurs following binding of all three substrates at a unique site. Alanine substitution of two amino acids, aspartic acid 127 and histidine 196 within the 5'-nucleotidase signature sequence, leads to reduced AMP or ADP hydrolysis but does not affect the binding of these substrates. Conclusion Collectively, these results provide insight into the unique ability of AdsA to produce adenosine through the consecutive hydrolysis of ATP, ADP and AMP, thereby endowing S. aureus with the ability to modulate host immune responses. PMID:22035583

  7. 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...... 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...

  8. Clinical characteristics in patients showing ischemic electrocardiographic changes during adenosine triphosphate loading single-photon emission computed tomography

    International Nuclear Information System (INIS)

    Ohtaki, Yuka; Chikamori, Taishiro; Hida, Satoshi; Tanaka, Hirokazu; Igarashi, Yuko; Hatano, Tsuguhisa; Usui, Yasuhiro; Miyagi, Manabu; Yamashina, Akira

    2010-01-01

    Although ischemic electrocardiographic (ECG) changes during dipyridamole or adenosine infusion have been reported as a marker for severe coronary artery disease (CAD), few studies have focused on ST-segment changes with adenosine triphosphate (ATP)-loading myocardial single-photon emission computed tomography (SPECT). Between January 2003 and August 2008, 4650 consecutive patients underwent ATP-loading SPECT. After 1412 patients with left bundle branch block, pacemaker rhythm, or previous coronary revascularization were excluded, 16 out of 3238 patients (0.5%) showed ischemic ST-segment depression during ATP-loading myocardial SPECT. They were aged 67±11 years; 10 were men and 6 women. Of these patients, 8 demonstrated perfusion abnormalities, whereas the remaining 8 showed normal myocardial perfusion imaging. In 6 of the 8 patients with abnormal SPECT, coronary angiography was performed, revealing left main trunk disease in 1 patient, 3-vessel disease in 4, 1-vessel disease with proximal left ascending artery occlusion in 1, and an insignificant lesion in 1. By contrast, no major cardiac event was observed in the 8 patients with normal SPECT during follow-up for an average of 2 years. The prevalence of ischemic ST-segment changes during ATP loading is very rare. However, this finding should be taken into account since almost half of the patients, particularly those with perfusion abnormalities, may have severe CAD which requires coronary revascularization. (author)

  9. Adsorption characteristics of 14C-labeled alanine, aspartic acid and adenosine triphosphate by metal-chelating resins

    International Nuclear Information System (INIS)

    Ishiyama, Toshio; Matsunami, Tadao; Shibata, Setsuko; Honda, Yoshihide.

    1987-01-01

    (1) Adsorption properties of 14 C-alanine, 14 C-ATP (adenosine triphosphate) and 14 C-aspartic acid on the metal-chelating resins were determined and found that the Cu(II)-Chelex 100 and Fe(III)-Unicellex UR10, Fe(III)-Chelex 100 chelating resins were highly effective for the adsorption of 14 C-alanine and 14 C-ATP, respectively. (2) Desorption rate of 14 C-ATP from the Fe(III)-Unicellex UR10 and Fe(III)-Chelex 100 resins was somewhat higher than the case of 14 C-alanine, probably because the coordination bonds of Cu-alanine might be stronger than those of Fe-ATP. Thus, 14 C-labeled organic compounds such as 14 C-alanine and 14 C-ATP of a low activity concentration (3.7 mBq/ml) (1 x 10 -7 μCi/ml) in aqueous solution may be measured with liquid scintillation counter after pre-concentration by use of the Fe(III)- and Cu(II)-chelating resin columns. (author)

  10. Photoinduced electron transfer between Fe(III) and adenosine triphosphate-BODIPY conjugates: Application to alkaline-phosphatase-linked immunoassay.

    Science.gov (United States)

    Lin, Jia-Hui; Yang, Ya-Chun; Shih, Ya-Chen; Hung, Szu-Ying; Lu, Chi-Yu; Tseng, Wei-Lung

    2016-03-15

    Fluorescent boron dipyrromethene (BODIPY) analogs are often used as sensors for detecting various species because of their relatively high extinction coefficients, outstanding fluorescence quantum yields, photostability, and pH-independent fluorescence. However, there is little-to-no information in the literature that describes the use of BODIPY analogs for detecting alkaline phosphatase (ALP) activity and inhibition. This study discovered that the fluorescence of BODIPY-conjugated adenosine triphosphate (BODIPY-ATP) was quenched by Fe(III) ions through photoinduced electron transfer. The ALP-catalyzed hydrolysis of BODIPY-ATP resulted in the formation of BODIPY-adenosine and phosphate ions. The fluorescence of the generated BODIPY-adenosine was insensitive to the change in the concentration of Fe(III) ions. Thus, the Fe(III)-induced fluorescence quenching of BODIPY-ATP can be paired with its ALP-mediated dephosphorylation to design a turn-on fluorescence probe for ALP sensing. A method detection limit at a signal-to-noise ratio of 3 for ALP was estimated to be 0.02 units/L (~6 pM; 1 ng/mL). This probe was used for the screening of ALP inhibitors, including Na3VO4, imidazole, and arginine. Because ALP is widely used in enzyme-linked immunosorbent assays, the probe was coupled to an ALP-linked immunosorbent assay for the sensitive and selective detection of immunoglobulin G (IgG). The lowest detectable concentration for IgG in this system was 5 ng/mL. Compared with the use of 3,6-fluorescein diphosphate as a signal reporter in an ALP-linked immunosorbent assay, the proposed system provided comparable sensitivity, large linear range, and high stability over temperature and pH changes. Copyright © 2015 Elsevier B.V. All rights reserved.

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

    International Nuclear Information System (INIS)

    Yao Zhiming; He Qing; Qu Wanying; Yu Xue; Han Lijun; Yu Zhiguo; Li Wei; Zeng Xuezhai; Zhu Ming; Zhao Hongshan

    2002-01-01

    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

  12. Influence of morphology and topography on potentiometric response of magnesium and calcium sensitive PEDOT films doped with adenosine triphosphate (ATP)

    International Nuclear Information System (INIS)

    Paczosa-Bator, B.; Peltonen, J.; Bobacka, J.; Lewenstam, A.

    2006-01-01

    Poly(3,4-ethylenedioxythiophene) (PEDOT) films doped with adenosine triphosphate (ATP) are used to study the biologically relevant competitive magnesium and calcium ion-exchange at ATP membrane sites. It is shown, by atomic force microscopy (AFM) and scanning electron microscopy (SEM), that the surface topography and morphology of the PEDOT-ATP films determines the quality of their potentiometric response. More smooth and less rough films result in better potentiometric characteristics, particularly in a faster response. The topography/morphology of the PEDOT-ATP films is influenced by conditions during electrodeposition (electrochemical method of deposition, pH, concentration of electrolytes) and post-deposition soaking (including net-time of soaking), as evidenced by X-ray photoelectron spectroscopy (XPS) and energy dispersive analysis of X-rays (EDAX)

  13. Heterogeneity of tumor chemosensitivity in ovarian epithelial cancer revealed using the adenosine triphosphate-tumor chemosensitivity assay.

    Science.gov (United States)

    Zhang, Jin; Li, Hongxia

    2015-05-01

    Ovarian cancer has a poor prognosis, primarily due to the heterogeneity in chemosensitivity among patients. In the present study, this heterogeneity was evaluated in ovarian epithelial cancer (OEC) using an in vitro adenosine triphosphate tumor chemosensitivity assay (ATP-TCA). Specimens were collected from 80 patients who underwent cytoreductive surgery. Viable ovarian cancer cells obtained from malignant tissues were tested for sensitivity to paclitaxel (PTX), carboplatin (CBP), topotecan (TPT), gemcitabine (GEM), docetaxel (TXT), etoposide, bleomycin and 4-hydroperoxycyclophosphamide using ATP-TCA. The sensitivity, specificity, positive predictive value and negative predictive value for the clinical chemotherapy sensitivity of OEC were 88.6, 77.8, 83 and 84.8%, respectively. PTX demonstrated the highest sensitivity of all agents tested (82.5% in all specimens, 85.7% in recurrent specimens), followed by CBP (58.8 and 60.7%, respectively). The sensitivities to PTX and docetaxel (PIII) or low-differentiated specimens, respectively. The present study indicated that ATP-TCA is an effective method for guiding the choice of chemotherapy drugs. Notable heterogeneity of chemosensitivity was observed in the OEC specimens.

  14. Intracellular and extracellular adenosine triphosphate in regulation of insulin secretion from pancreatic β cells (β).

    Science.gov (United States)

    Wang, Chunjiong; Geng, Bin; Cui, Qinghua; Guan, Youfei; Yang, Jichun

    2014-03-01

    Adenosine triphosphate (ATP) synthesis and release in mitochondria play critical roles in regulating insulin secretion in pancreatic β cells. Mitochondrial dysfunction is mainly characterized by a decrease in ATP production, which is a central event in the progression of pancreatic β cell dysfunction and diabetes. ATP has been demonstrated to regulate insulin secretion via several pathways: (i) Intracellular ATP directly closes ATP-sensitive potassium channel to open L-type calcium channel, leading to an increase in free cytosolic calcium levels and exocytosis of insulin granules; (ii) A decrease in ATP production is always associated with an increase in production of reactive oxygen species, which exerts deleterious effects on pancreatic β cell survival and insulin secretion; and (iii) ATP can be co-secreted with insulin from pancreatic β cells, and the released ATP functions as an autocrine signal to modulate insulin secretory process via P2 receptors on the cell membrane. In this review, the recent findings regarding the role and mechanism of ATP synthesis and release in regulation of insulin secretion from pancreatic β cells will be summarized and discussed. © 2013 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and Wiley Publishing Asia Pty Ltd.

  15. Effects of 5 Thio-D-Glucose on cellular adenosine triphosphate levels and deoxyribonucleic acid rejoining in hypoxic and aerobic Chinese hamster cells

    International Nuclear Information System (INIS)

    Nagle, W.A.; Moss, A.J. Jr.; Roberts, H.G. Jr.; Baker, M.L.

    1980-01-01

    Intracellular adenosine triphosphate (ATP) levels were measured in both hypoxic and aerobic cultures of V79 Chinese hamster cells treated with 5-thio-D-glucose (5-SH-D-Glc). This glucose analog, a known inhibitor of D-glucose transport and metabolism, reduced ATP in cell cultures allowed to become hypoxic by cell metabolism, but not in aerobic cultures treated similarly. Cells depleted of ATP were unable to rejoin x-ray induced deoxyribonucleic acid (DNA) strand breaks as measured by the alkaline sucrose gradient sedimentation technique. The inference for radiation therapy is that inhibition of glucose metabolism selectively depletes energy reserves in hypoxic cells, rendering these cells more radiosensitive and leading to a more effective tumor treatment

  16. Prolonged Atrioventricular Block and Ventricular Standstill Following Adenosine Triphosphate Injection in a Patient Taking Dipyridamole and Antiarrhythmic Agents: A Case Report

    Directory of Open Access Journals (Sweden)

    Kotaro Oe, MD

    2009-01-01

    Full Text Available An 83-year-old woman was admitted to our hospital because of palpitation. She had hypertension and paroxysmal atrial fibrillation, treated with digoxin and cibenzoline, and took dipyridamole for microalbuminuria. Before admission, she had taken pilsicainide pills in addition. On admission, electrocardiogram showed regular tachycardia with mildly prolonged QRS width. For the purpose of terminating tachycardia, 10 mg of adenosine triphosphate (ATP was rapidly injected. About 20 sec later, atrioventricular block and ventricular standstill occurred. She presented loss of consciousness and convulsion, and chest compression was performed. About 30 sec later, the QRS complex reappeared, and she became alert. Serum concentration of digoxin, cibenzoline and pilsicainide was within therapeutic level, respectively. We should be cautious in using ATP for a patient taking dipyridamole and antiarrhythmic agents.

  17. 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.

  18. Cloning and bacterial expression of adenosine-5'-triphosphate sulfurylase from the enteric protozoan parasite Entamoeba histolytica.

    Science.gov (United States)

    Nozaki, T; Arase, T; Shigeta, Y; Asai, T; Leustek, T; Takeuchi, T

    1998-12-08

    A gene encoding adenosine-5'-triphosphate sulfurylase (AS) was cloned from the enteric protozoan parasite Entamoeba histolytica by polymerase chain reaction using degenerate oligonucleotide primers corresponding to conserved regions of the protein from a variety of organisms. The deduced amino acid sequence of E. histolytica AS revealed a calculated molecular mass of 47925 Da and an unusual basic pI of 9.38. The amebic protein sequence showed 23-48% identities with AS from bacteria, yeasts, fungi, plants, and animals with the highest identities being to Synechocystis sp. and Bacillus subtilis (48 and 44%, respectively). Four conserved blocks including putative sulfate-binding and phosphate-binding regions were highly conserved in the E. histolytica AS. The upstream region of the AS gene contained three conserved elements reported for other E. histolytica genes. A recombinant E. histolytica AS revealed enzymatic activity, measured in both the forward and reverse directions. Expression of the E. histolytica AS complemented cysteine auxotrophy of the AS-deficient Escherichia coli strains. Genomic hybridization revealed that the AS gene exists as a single copy gene. In the literature, this is the first description of an AS gene in Protozoa.

  19. Oral sucrose for heel lance increases adenosine triphosphate use and oxidative stress in preterm neonates.

    Science.gov (United States)

    Asmerom, Yayesh; Slater, Laurel; Boskovic, Danilo S; Bahjri, Khaled; Holden, Megan S; Phillips, Raylene; Deming, Douglas; Ashwal, Stephen; Fayard, Elba; Angeles, Danilyn M

    2013-07-01

    To examine the effects of sucrose on pain and biochemical markers of adenosine triphosphate (ATP) degradation and oxidative stress in preterm neonates experiencing a clinically required heel lance. Preterm neonates that met study criteria (n = 131) were randomized into 3 groups: (1) control; (2) heel lance treated with placebo and non-nutritive sucking; and (3) heel lance treated with sucrose and non-nutritive sucking. Plasma markers of ATP degradation (hypoxanthine, xanthine, and uric acid) and oxidative stress (allantoin) were measured before and after the heel lance. Pain was measured with the Premature Infant Pain Profile. Data were analyzed by the use of repeated-measures ANOVA and Spearman rho. We found significant increases in plasma hypoxanthine and uric acid over time in neonates who received sucrose. We also found a significant negative correlation between pain scores and plasma allantoin concentration in a subgroup of neonates who received sucrose. A single dose of oral sucrose, given before heel lance, significantly increased ATP use and oxidative stress in premature neonates. Because neonates are given multiple doses of sucrose per day, randomized trials are needed to examine the effects of repeated sucrose administration on ATP degradation, oxidative stress, and cell injury. Copyright © 2013 Mosby, Inc. All rights reserved.

  20. 21 CFR 73.2120 - Disodium EDTA-copper.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Disodium EDTA-copper. 73.2120 Section 73.2120 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2120 Disodium EDTA-copper. (a) Identity. The color additive disodium EDTA-copper is disodium [[N,N′- 1,2- ethanediylbis[N - (carboxymethyl) glycinato...

  1. Fluorescence detection of DNA, adenosine-5'-triphosphate (ATP), and telomerase activity by zinc(II)-protoporphyrin IX/G-quadruplex labels.

    Science.gov (United States)

    Zhang, Zhanxia; Sharon, Etery; Freeman, Ronit; Liu, Xiaoqing; Willner, Itamar

    2012-06-05

    The zinc(II)-protoporphyrin IX (ZnPPIX) fluorophore binds to G-quadruplexes, and this results in the enhanced fluorescence of the fluorophore. This property enabled the development of DNA sensors, aptasensors, and a sensor following telomerase activity. The DNA sensor is based on the design of a hairpin structure that includes a "caged" inactive G-quadruplex sequence. Upon opening the hairpin by the analyte DNA, the resulting fluorescence of the ZnPPIX/G-quadruplex provides the readout signal for the sensing event (detection limit 5 nM). Addition of Exonuclease III to the system allows the recycling of the analyte and its amplified analysis (detection limit, 200 pM). The association of the ZnPPIX to G-quadruplex aptamer-substrate complexes allowed the detection of adenosine-5'-triphosphate (ATP, detection limit 10 μM). Finally, the association of ZnPPIX to the G-quadruplex repeat units of telomers allowed the detection of telomerase activity originating from 380 ± 20 cancer 293T cell extract.

  2. Adenosine triphosphate hydrolysis reduces neutrophil infiltration and necrosis in partial-thickness scald burns in mice.

    Science.gov (United States)

    Bayliss, Jill; Delarosa, Sara; Wu, Jianfeng; Peterson, Jonathan R; Eboda, Oluwatobi N; Su, Grace L; Hemmila, Mark; Krebsbach, Paul H; Cederna, Paul S; Wang, Stewart C; Xi, Chuanwu; Levi, Benjamin

    2014-01-01

    Extracellular adenosine triphosphate (ATP), present in thermally injured tissue, modulates the inflammatory response and causes significant tissue damage. The authors hypothesize that neutrophil infiltration and ensuing tissue necrosis would be mitigated by removing ATP-dependent signaling at the burn site. Mice were subjected to 30% TBSA partial-thickness scald burn by dorsal skin immersion in a water bath at 60 or 20°C (nonburn controls). In the treatment arm, an ATP hydrolyzing enzyme, apyrase, was applied directly to the site immediately after injury. Skin was harvested after 24 hours and 5 days for hematoxylin and eosin stain, elastase, and Ki-67 staining. Tumor necrosis factor (TNF)-α and interferon (IFN)-β expression were measured through quantitative real-time polymerase chain reaction. At 24 hours, the amount of neutrophil infiltration was different between the burn and burn + apyrase groups (P burn group at 24 hours and 5 days. TNF-α and IFN-β expression at 24 hours in the apyrase group was lower than in the burn group (P burn site allays the neutrophil response to thermal injury and reduces tissue necrosis. This decrease in inflammation and tissue necrosis is at least partially because of TNF-α and IFN-β signaling. Apyrase could be used as topical inflammatory regulators to quell the injury caused by inflammation.

  3. Thiamin diphosphate in biological chemistry: new aspects of thiamin metabolism, especially triphosphate derivatives acting other than as cofactors.

    Science.gov (United States)

    Bettendorff, Lucien; Wins, Pierre

    2009-06-01

    Prokaryotes, yeasts and plants synthesize thiamin (vitamin B1) via complex pathways. Animal cells capture the vitamin through specific high-affinity transporters essential for internal thiamin homeostasis. Inside the cells, thiamin is phosphorylated to higher phosphate derivatives. Thiamin diphosphate (ThDP) is the best-known thiamin compound because of its role as an enzymatic cofactor. However, in addition to ThDP, at least three other thiamin phosphates occur naturally in most cells: thiamin monophosphate, thiamin triphosphate (ThTP) and the recently discovered adenosine thiamin triphosphate. It has been suggested that ThTP has a specific neurophysiological role, but recent data favor a much more basic metabolic function. During amino acid starvation, Escherichia coli accumulate ThTP, possibly acting as a signal involved in the adaptation of the bacteria to changing nutritional conditions. In animal cells, ThTP can phosphorylate some proteins, but the physiological significance of this mechanism remains unknown. Adenosine thiamin triphosphate, recently discovered in E. coli, accumulates during carbon starvation and might act as an alarmone. Among the proteins involved in thiamin metabolism, thiamin transporters, thiamin pyrophosphokinase and a soluble 25-kDa thiamin triphosphatase have been characterized at the molecular level, in contrast to thiamin mono- and diphosphatases whose specificities remain to be proven. A soluble enzyme catalyzing the synthesis of adenosine thiamin triphosphate from ThDP and ADP or ATP has been partially characterized in E. coli, but the mechanism of ThTP synthesis remains elusive. The data reviewed here illustrate the complexity of thiamin biochemistry, which is not restricted to the cofactor role of ThDP.

  4. A quantitative analysis of the effects of 2,3-diphosphoglycerate, adenosine triphosphate and inositol hexaphosphate on the oxygen dissociation curve of human haemoglobin.

    Science.gov (United States)

    Goodford, P J; St-Louis, J; Wootton, R

    1978-01-01

    1. Oxygen dissociation curves have been measured for human haemoglobin solutions with different concentrations of the allosteric effectors 2,3-diphosphoglycerate, adenosine triphosphate and inositol hexaphosphate. 2. Each effector produces a concentration dependent right shift of the oxygen dissociation curve, but a point is reached where the shift is maximal and increasing the effector concentration has no further effect. 3. Mathematical models based on the Monod, Wyman & Changeux (1965) treatment of allosteric proteins have been fitted to the data. For each compound the simple two-state model and its extension to take account of subunit inequivalence were shown to be inadequate, and a better fit was obtained by allowing the effector to lower the oxygen affinity of the deoxy conformational state as well as binding preferentially to this conformation. PMID:722582

  5. Use of adenosine triphosphate to audit reprocessing of flexible endoscopes with an elevator mechanism.

    Science.gov (United States)

    Quan, Erik; Mahmood, Rizwan; Naik, Amar; Sargon, Peter; Shastri, Nikhil; Venu, Mukund; Parada, Jorge P; Gupta, Neil

    2018-05-21

    There have been reported outbreaks of carbapenem-resistant Enterobacteriaceae infections linked to endoscopes with elevator mechanisms. Adenosine triphosphate (ATP) testing has been used as a marker for bioburden and monitoring manual cleaning for flexible endoscopes with and without an elevator mechanism. The objective of this study was to determine whether routine ATP testing could identify areas of improvement in cleaning of endoscopes with an elevator mechanism. ATP testing after manual cleaning of TJF-Q180V duodenoscopes and GF-UCT180 linear echoendoscopes (Olympus America Inc, Center Valley, PA) was implemented. Samples were tested from the distal end, the elevator mechanism, and water flushed through the lumen of the biopsy channel. Data were recorded and compared by time point, test point, and reprocessing technician. Overall failure rate was 6.99% (295 out of 4,219). The highest percentage of failed ATP tests (17.05%) was reported in the first quarter of routine testing, with an overall decrease in rates over time. The elevator mechanism and working channel lumen had higher failure rates than the distal end. Quality of manual cleaning between reprocessing technicians showed variation. ATP testing is effective in identifying residual organic material and improving quality of manual cleaning of endoscopes with an elevator mechanism. Cleaning efficacy is influenced by reprocessing technicians and location tested on the endoscope. Close attention to the working channel and elevator mechanism during manual cleaning is warranted. Copyright © 2018 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  6. A novel fluorescent biosensor for Adenosine Triphosphate detection based on the polydopamine nanospheres integrating with enzymatic recycling amplification.

    Science.gov (United States)

    Ji, Xiaoting; Yi, Bingqing; Xu, Yujuan; Zhao, Yanan; Zhong, Hua; Ding, Caifeng

    2017-07-01

    Based on the protective performance of polydopamine nanospheres (PDANSs) for DNA against nuclease digestion and the specific recognition characteristic of aptamer, we have developed an enzymatic recycling signal amplification method for highly sensitive and selective detection of adenosine triphosphate (ATP). Fluorescence measurements were carried out to verify the DNA polymerase and exonuclease III (Exo III) assisted target recycling process and fluorescence signal amplification. In the absence of the ATP, initially, the signal DNA-PDANSs complex was in the "off" state due to the efficient fluorescence quenching of 6-carboxyfluorescein (FAM) adjacent to the surface of PDANSs. Due to the binding of the aptamer by ATP, it trigger DNA polymerase and Exo III assisted target recycling process by the product of release, the complex would change into the "on" state as a result of the dissociation of the FAM from the surface of PDANSs, thus providing greatly enhanced fluorescence emission intensity. The method allows quantitative detection of ATP in the range of 20-600nM with a detection limit of 8.32nM. This biosensor requires no complex operations, and is a new high efficiency method for ATP detection. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Measurement of adenosine triphosphate and 2,3-diphosphoglycerate in stored blood with 31P nuclear magnetic resonance spectroscopy.

    Science.gov (United States)

    Ambruso, D R; Hawkins, B; Johnson, D L; Fritzberg, A R; Klingensmith, W C; McCabe, E R

    1986-06-01

    Conditions for blood storage are chosen to assure adequate levels of adenosine triphosphate (ATP) and 2,3-diphosphoglycerate (2,3-DPG). Because of the invasive nature of the techniques, biochemical assays are not routinely used to measure levels of these compounds in stored blood. However, 31P NMR spectroscopy measures phosphorylated intermediates in intact cells and could be used without disruption of the storage pack. We compared levels of ATP and 2,3-DPG measured by 31P spectroscopy and standard enzyme-linked biochemical assays in whole blood (WB) and packed red blood cells (PRBCs) at weekly intervals during a 35-day storage period. NMR demonstrated a marked decrease in 2,3-DPG and an increase in inorganic phosphate after the first week of storage. No significant differences in ATP concentrations were seen in WB during the storage period, but a significant decrease in ATP in PRBCs was documented. There was good agreement in levels of ATP and 2,3-DPG measured by NMR and biochemical techniques. 31P NMR spectroscopy is a noninvasive technique for measuring ATP and 2,3-DPG which has a potential use in quality assurance of stored blood.

  8. Photoaffinity labeling of myosin subfragment-one-with 3'(2')-O-(4-benzoyl)benzoyl adenosine 5'-triphosphate

    International Nuclear Information System (INIS)

    Mahmood, R.

    1985-01-01

    The photoaffinity analogue 3'(2')-O-(4-benzoyl)benzoyl adenosine 5'-triphosphate (Bz 2 ATP) contains the photoreactive benzophenone group esterified at the 2' or 3' hydroxyl groups of ribose. MgBz 2 ADP has a single binding site on skeletal myosin chymotryptic subfragment-one (SF 1 ) with a binding constant of 3.2 x 10 5 M -1 . Bz 2 ATP is also a substrate for the ATPase activity of SF 1 in the presence of different cations. The irradiation of SF 1 with [ 3 H]Bz 2 ATP photoinactivates the ATPase activity with concomitant incorporation of the analogue into the enzyme. Polyacrylamide gel electrophoresis of photolabeled SF 1 after milk trypsin digestion shows that all three tryptic peptides, 25 K, 50K, and 20 K, and both light chains are labeled. The presence of ATP during irradiation reduces labeling of the 50 K peptide only indicating that the other peptides are non-specifically labeled. To reduce the non-specific labeling [ 3 H]Bz 2 ATP is trapped on SF 1 by cross-linking the two reactive thiols, SH 1 and SH 2 , by N,N'-p-phenylene dimaleimide or Co(II)/Co(III) phenanthroline complexes. The Co(II)/Co(III) phenanthroline modified [ 14 C]Bz 2 ATP-SF 1 , after proteolytic digestion, yields five labeled peptides which were purified by gel filtration and high performance liquid chromatography

  9. Antifouling aptasensor for the detection of adenosine triphosphate in biological media based on mixed self-assembled aptamer and zwitterionic peptide.

    Science.gov (United States)

    Wang, Guixiang; Su, Xiaoli; Xu, Qingjun; Xu, Guiyun; Lin, Jiehua; Luo, Xiliang

    2018-03-15

    Direct detection of targets in complex biological media with conventional biosensors is an enormous challenge due to the nonspecific adsorption and severe biofouling. In this work, a facile strategy for sensitive and low fouling detection of adenosine triphosphate (ATP) is developed through the construction of a mixed self-assembled biosensing interface, which was composed of zwitterionic peptide (antifouling material) and ATP aptamer (bio-recognition element). The peptide and aptamer (both containing thiol groups) were simultaneously self-assembled onto gold electrode surface electrodeposited with gold nanoparticles. The developed aptasensor possessed high selectivity and sensitivity for ATP, and it showed a wide linear response range towards ATP from 0.1pM to 5nM. Owing to the presence of peptide with excellent antifouling property in the biosensing interface, the aptasensor can detect ATP in complex biological media with remarkably reduced biofouling or nonspecific adsorption effect. Moreover, it can directly detect ATP in 1% human whole blood without suffering from any significant interference, indicating its great potential for practical assaying of ATP in biological samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Enzyme-free and label-free ultrasensitive electrochemical detection of DNA and adenosine triphosphate by dendritic DNA concatamer-based signal amplification.

    Science.gov (United States)

    Liu, Shufeng; Lin, Ying; Liu, Tao; Cheng, Chuanbin; Wei, Wenji; Wang, Li; Li, Feng

    2014-06-15

    Hybridization chain reaction (HCR) strategy has been well developed for the fabrication of various biosensing platforms for signal amplification. Herein, a novel enzyme-free and label-free ultrasensitive electrochemical DNA biosensing platform for the detection of target DNA and adenosine triphosphate (ATP) was firstly proposed, in which three auxiliary DNA probes were ingeniously designed to construct the dendritic DNA concatamer via HCR strategy and used as hexaammineruthenium(III) chloride (RuHex) carrier for signal amplification. With the developed dendritic DNA concatamer-based signal amplification strategy, the DNA biosensor could achieve an ultrasensitive electrochemical detection of DNA and ATP with a superior detection limit as low as 5 aM and 20 fM, respectively, and also demonstrate a high selectivity for DNA and ATP detection. The currently proposed dendritic DNA concatamer opens a promising direction to construct ultrasensitive DNA biosensing platform for biomolecular detection in bioanalysis and clinical biomedicine, which offers the distinct advantages of simplicity and cost efficiency owing to no need of any kind of enzyme, chemical modification or labeling. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Ternary Interactions and Energy Transfer between Fluorescein Isothiocyanate, Adenosine Triphosphate, and Graphene Oxide Nanocarriers.

    Science.gov (United States)

    Ratajczak, Katarzyna; Stobiecka, Magdalena

    2017-07-20

    The interactions of fluorescent probes and biomolecules with nanocarriers are of key importance to the emerging targeted drug delivery systems. Graphene oxide nanosheets (GONs) as the nanocarriers offer biocompatibility and robust drug binding capacity. The interactions of GONs with fluorophores lead to strong fluorescence quenching, which may interfere with fluorescence bioimaging and biodetection. Herein, we report on the interactions and energy transfers in a model ternary system: GONs-FITC-ATP, where FITC is a model fluorophore (fluorescein isothiocyanate) and ATP is a common biomolecule (adenosine-5'-triphosphate). We have found that FITC fluorescence is considerably quenched by ATP (the quenching constant K SV = 113 ± 22 M -1 ). The temperature coefficient of K SV is positive (α T = 4.15 M -1 deg -1 ). The detailed analysis of a model for internal self-quenching of FITC indicates that the temperature dependence of the net quenching efficiency η for the FITC-ATP pair is dominated by FITC internal self-quenching modes with their contribution estimated at 79%. The quenching of FITC by GONs is much stronger (K SV = 598 ± 29 M -1 ) than that of FITC-ATP and is associated with the formation of supramolecular assemblies bound with hydrogen bonding and π-π stacking interactions. For the analysis of the complex behavior of the ternary system GONs-FITC-ATP, a model of chemisorption of ATP on GONs, with partial blocking of FITC quenching, has been developed. Our results indicate that ATP acts as a moderator for FITC quenching by GONs. The interactions between ATP, FITC, and GONs have been corroborated using molecular dynamics and quantum mechanical calculations.

  12. Visual and surface plasmon resonance sensor for zirconium based on zirconium-induced aggregation of adenosine triphosphate-stabilized gold nanoparticles.

    Science.gov (United States)

    Qi, Wenjing; Zhao, Jianming; Zhang, Wei; Liu, Zhongyuan; Xu, Min; Anjum, Saima; Majeed, Saadat; Xu, Guobao

    2013-07-17

    Owing to its high affinity with phosphate, Zr(IV) can induce the aggregation of adenosine 5'-triphosphate (ATP)-stabilized AuNPs, leading to the change of surface plasmon resonance (SPR) absorption spectra and color of ATP-stabilized AuNP solutions. Based on these phenomena, visual and SPR sensors for Zr(IV) have been developed for the first time. The A(660 nm)/A(518 nm) values of ATP-stabilized AuNPs in SPR absorption spectra increase linearly with the concentrations of Zr(IV) from 0.5 μM to 100 μM (r=0.9971) with a detection limit of 95 nM. A visual Zr(IV) detection is achieved with a detection limit of 30 μM. The sensor shows excellent selectivity against other metal ions, such as Cu(2+), Fe(3+), Cd(2+), and Pb(2+). The recoveries for the detection of 5 μM, 10 μM, 25 μM and 75 μM Zr(IV) in lake water samples are 96.0%, 97.0%, 95.6% and 102.4%, respectively. The recoveries of the proposed SPR method are comparable with those of ICP-OES method. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Increased activity of vascular adenosine deaminase in atherosclerosis and therapeutic potential of its inhibition.

    Science.gov (United States)

    Kutryb-Zajac, Barbara; Mateuszuk, Lukasz; Zukowska, Paulina; Jasztal, Agnieszka; Zabielska, Magdalena A; Toczek, Marta; Jablonska, Patrycja; Zakrzewska, Agnieszka; Sitek, Barbara; Rogowski, Jan; Lango, Romuald; Slominska, Ewa M; Chlopicki, Stefan; Smolenski, Ryszard T

    2016-11-01

    Extracellular nucleotides and adenosine that are formed or degraded by membrane-bound ecto-enzymes could affect atherosclerosis by regulating the inflammation and thrombosis. This study aimed to evaluate a relation between ecto-enzymes that convert extracellular adenosine triphosphate to adenine dinucleotide phosphate, adenosine monophosphate, adenosine, and inosine on the surface of the vessel wall with the severity or progression of experimental and clinical atherosclerosis. Furthermore, we tested whether the inhibition of adenosine deaminase will block the development of experimental atherosclerosis. Vascular activities of ecto-nucleoside triphosphate diphosphohydrolase 1, ecto-5'-nucleotidase, and ecto-adenosine deaminase (eADA) were measured in aortas of apolipoprotein E-/- low density lipoprotein receptor (ApoE-/-LDLR-/-) and wild-type mice as well as in human aortas. Plaques were analysed in the entire aorta, aortic root, and brachiocephalic artery by Oil-Red O and Orcein Martius Scarlet Blue staining and vascular accumulation of macrophages. The cellular location of ecto-enzymes was analysed by immunofluorescence. The effect of eADA inhibition on atherosclerosis progression was studied by a 2-month deoxycoformycin treatment of ApoE-/-LDLR-/- mice. The vascular eADA activity prominently increased in ApoE-/-LDLR-/- mice when compared with wild type already at the age of 1 month and progressed along atherosclerosis development, reaching a 10-fold difference at 10 months. The activity of eADA correlated with atherosclerotic changes in human aortas. High abundance of eADA in atherosclerotic vessels originated from activated endothelial cells and macrophages. There were no changes in ecto-nucleoside triphosphate diphosphohydrolase 1 activity, whereas ecto-5'-nucleotidase was moderately decreased in ApoE-/-LDLR-/- mice. Deoxycoformycin treatment attenuated plaque development in aortic root and brachiocephalic artery of ApoE-/-LDLR-/- mice, suppressed vascular

  14. Kinetic, spectroscopic and chemical modification study of iron release from transferrin; iron(III) complexation to adenosine triphosphate

    International Nuclear Information System (INIS)

    Thompson, C.P.

    1985-01-01

    Amino acids other than those that serve as ligands have been found to influence the chemical properties of transferrin iron. The catalytic ability of pyrophosphate to mediate transferrin iron release to a terminal acceptor is largely quenched by modification non-liganded histine groups on the protein. The first order rate constants of iron release for several partially histidine modified protein samples were measured. A statistical method was employed to establish that one non-liganded histidine per metal binding domain was responsible for the reduction in rate constant. These results imply that the iron mediated chelator, pyrophosphate, binds directly to a histidine residue on the protein during the iron release process. EPR spectroscopic results are consistent with this interpretation. Kinetic and amino acid sequence studies of ovotransferrin and lactoferrin, in addition to human serum transferrin, have allowed the tentative assignment of His-207 in the N-terminal domain and His-535 in the C-terminal domain as the groups responsible for the reduction in rate of iron release. The above concepts have been extended to lysine modified transferrin. Complexation of iron(II) to adenosine triphosphate (ATP) was also studied to gain insight into the nature of iron-ATP species present at physiological pH. 31 P NMR spectra are observed when ATP is presented in large excess

  15. Carbon quantum dots-based recyclable real-time fluorescence assay for alkaline phosphatase with adenosine triphosphate as substrate.

    Science.gov (United States)

    Qian, Zhaosheng; Chai, Lujing; Tang, Cong; Huang, Yuanyuan; Chen, Jianrong; Feng, Hui

    2015-03-03

    A convenient, reliable, and highly sensitive real-time assay for alkaline phosphatase (ALP) activity in the continuous and recyclable way is established on the basis of aggregation and disaggregation of carbon quantum dots (CQDs) through the competitive assay approach. CQDs and adenosine triphosphate (ATP) were used as the fluorescent indicator and substrate for ALP activity assessment, respectively. Richness of carboxyl groups on the surface of CQDs enables their severe aggregation triggered by cerium ions, which results in effective fluorescence quenching. Under the catalytic hydrolysis of ALP, ATP can be rapidly transformed to phosphate ions. Stronger affinity of phosphate ions to cerium ions than carboxyl groups is taken advantage of to achieve fluorescence recovery induced by redispersion of CQDs in the presence of ALP and ATP. Quantitative evaluation of ALP activity in a broad range from 4.6 to 383.3 U/L with the detection limit of 1.4 U/L can be realized in this way, which endows the assay with high enough sensitivity for practical detection in human serum. The assay can be used in a recyclable way for more than three times since the generated product CePO4 as a precipitate can be easily removed from the standard assay system. This strategy broadens the sensing application of fluorescent CQDs with excellent biocompatibility and provides an example based on disaggregation in optical probe development.

  16. Rapid detection of Escherichia coli and enterococci in recreational water using an immunomagnetic separation/adenosine triphosphate technique

    Science.gov (United States)

    Bushon, R.N.; Brady, A.M.; Likirdopulos, C.A.; Cireddu, J.V.

    2009-01-01

    Aims: The aim of this study was to examine a rapid method for detecting Escherichia coli and enterococci in recreational water. Methods and Results: Water samples were assayed for E. coli and enterococci by traditional and immunomagnetic separation/adenosine triphosphate (IMS/ATP) methods. Three sample treatments were evaluated for the IMS/ATP method: double filtration, single filtration, and direct analysis. Pearson's correlation analysis showed strong, significant, linear relations between IMS/ATP and traditional methods for all sample treatments; strongest linear correlations were with the direct analysis (r = 0.62 and 0.77 for E. coli and enterococci, respectively). Additionally, simple linear regression was used to estimate bacteria concentrations as a function of IMS/ATP results. The correct classification of water-quality criteria was 67% for E. coli and 80% for enterococci. Conclusions: The IMS/ATP method is a viable alternative to traditional methods for faecal-indicator bacteria. Significance and Impact of the Study: The IMS/ATP method addresses critical public health needs for the rapid detection of faecal-indicator contamination and has potential for satisfying US legislative mandates requiring methods to detect bathing water contamination in 2 h or less. Moreover, IMS/ATP equipment is considerably less costly and more portable than that for molecular methods, making the method suitable for field applications. ?? 2009 The Authors.

  17. Endogenous adenosine produced during hypoxia attenuates neutrophil accumulation: coordination by extracellular nucleotide metabolism.

    Science.gov (United States)

    Eltzschig, Holger K; Thompson, Linda F; Karhausen, Jorn; Cotta, Richard J; Ibla, Juan C; Robson, Simon C; Colgan, Sean P

    2004-12-15

    Hypoxia is a well-documented inflammatory stimulus and results in tissue polymorphonuclear leukocyte (PMN) accumulation. Likewise, increased tissue adenosine levels are commonly associated with hypoxia, and given the anti-inflammatory properties of adenosine, we hypothesized that adenosine production via adenine nucleotide metabolism at the vascular surface triggers an endogenous anti-inflammatory response during hypoxia. Initial in vitro studies indicated that endogenously generated adenosine, through activation of PMN adenosine A(2A) and A(2B) receptors, functions as an antiadhesive signal for PMN binding to microvascular endothelia. Intravascular nucleotides released by inflammatory cells undergo phosphohydrolysis via hypoxia-induced CD39 ectoapyrase (CD39 converts adenosine triphosphate/adenosine diphosphate [ATP/ADP] to adenosine monophosphate [AMP]) and CD73 ecto-5'-nucleotidase (CD73 converts AMP to adenosine). Extensions of our in vitro findings using cd39- and cd73-null animals revealed that extracellular adenosine produced through adenine nucleotide metabolism during hypoxia is a potent anti-inflammatory signal for PMNs in vivo. These findings identify CD39 and CD73 as critical control points for endogenous adenosine generation and implicate this pathway as an innate mechanism to attenuate excessive tissue PMN accumulation.

  18. Label-free fluorescence strategy for sensitive detection of adenosine triphosphate using a loop DNA probe with low background noise.

    Science.gov (United States)

    Lin, Chunshui; Cai, Zhixiong; Wang, Yiru; Zhu, Zhi; Yang, Chaoyong James; Chen, Xi

    2014-07-15

    A simple, rapid, label-free, and ultrasensitive fluorescence strategy for adenosine triphosphate (ATP) detection was developed using a loop DNA probe with low background noise. In this strategy, a loop DNA probe, which is the substrate for both ligation and digestion enzyme reaction, was designed. SYBR green I (SG I), a double-stranded specific dye, was applied for the readout fluorescence signal. Exonuclease I (Exo I) and exonuclease III (Exo III), sequence-independent nucleases, were selected to digest the loop DNA probe in order to minimize the background fluorescence signal. As a result, in the absence of ATP, the loop DNA was completely digested by Exo I and Exo III, leading to low background fluorescence owing to the weak electrostatic interaction between SG I and mononucleotides. On the other hand, ATP induced the ligation of the nicking site, and the sealed loop DNA resisted the digestion of Exo I and ExoIII, resulting in a remarkable increase of fluorescence response. Upon background noise reduction, the sensitivity of the ATP determination was improved significantly, and the detection limitation was found to be 1.2 pM, which is much lower than that in almost all the previously reported methods. This strategy has promise for wide application in the determination of ATP.

  19. Adenosine triphosphate-based chemotherapy response assay (ATP-CRA)-guided versus empirical chemotherapy in unresectable non-small cell lung cancer.

    Science.gov (United States)

    Moon, Yong Wha; Sohn, Joo Hyuk; Kim, Yong Tai; Chang, Hyun; Jeong, Jae Heon; Lee, Young Joo; Chang, Joon; Kim, Se Kyu; Jung, Minkyu; Hong, Soojung; Choi, Sung Ho; Kim, Joo-Hang

    2009-10-01

    We retrospectively compared adenosine triphosphate-based chemotherapy response assay (ATP-CRA)-guided and empirical chemotherapies for unresectable non-small cell lung cancer (NSCLC) in this case-control study. Unresectable NSCLC patients receiving ATP-CRA-guided platinum-based doublets as first-line therapy were enrolled as cases (n=27; 14 platinum-sensitive and 13 platinum-resistant patients). Performance status, stage, and chemotherapeutic regimen-matched patients receiving empirical chemotherapy were selected from the retrospective database as controls (n=93) in a case to control ratio of approximately 1:3. Response rate and survival (progression-free; overall) in both groups were not significantly different. However, the platinum-sensitive subgroup by ATP-CRA showed a higher response rate than the empirical group (71 versus 38%; p=0.023) with a trend toward longer progression-free survival (8.7 versus 4.8 months for platinum-sensitive versus empirical; p=0.223) and overall survival (not reached versus 12.6 months for platinum-sensitive versus empirical for p=0.134). ATP-CRA may be helpful in selecting platinum-responsive patients in unresectable NSCLC. We consider that nonplatinum doublets in platinum-resistant patients by ATP-CRA may be a more adapted approach than platinum-based doublets in future clinical trials.

  20. A feasibility study of adenosine triphosphate-based chemotherapy response assay (ATP-CRA) as a chemosensitivity test for lung cancer.

    Science.gov (United States)

    Kang, Shin Myung; Park, Moo Suk; Chang, Joon; Kim, Se Kyu; Kim, Haeryoung; Shin, Dong-Hwan; Chung, Kyung Young; Kim, Dae Joon; Sohn, Joo Hyuk; Choi, Sung Ho; Kim, Jeongmi; Yoon, Eun Jin; Kim, Joo-Hang

    2005-08-01

    A chemosensitivity test can reflect the differences in responses of individual cancer patients to chemotherapeutic agents. The adenosine triphosphate-based chemotherapy response assay (ATP-CRA) is an accurate method, which does not require a large amount of tissue specimen. So far, no studies have evaluated the utility of the ATP-CRA in Korea. Therefore, we investigated the clinical usefulness of the ATP-CRA in 53 patients with lung cancer. Tumor tissues were obtained from bronchoscopic biopsies or surgical resections. The validity of ATP-CRA was assessed focusing on the success rate, experimental error level (intraassay mean coefficient of variation [CV]) and reproducibility. The overall success rate of ATP-CRA was 90.6% (48/53). Normal cells were effectively eliminated from the tumor tissues with the use of ficoll gradient centrifugation and immunomagnetic separation, which was confirmed using loss of heterozygosity analysis of the 3p deletion. The mean CV of ATP assays was 10.5+/-4.6%. The reproducibility of ATP assays was 94+/-3.8%. The results of the ATP assays were reported to physicians within 7 days of specimen collection. More than 6 anticancer drugs were tested on the tumor specimens obtained from bronchoscopic biopsies. The ATP-CRA is a stable, accurate and potentially practical chemosensitivity test in patients with lung cancer.

  1. Gravity loading induces adenosine triphosphate release and phosphorylation of extracellular signal-regulated kinases in human periodontal ligament cells.

    Science.gov (United States)

    Ito, Mai; Arakawa, Toshiya; Okayama, Miki; Shitara, Akiko; Mizoguchi, Itaru; Takuma, Taishin

    2014-11-01

    The periodontal ligament (PDL) receives mechanical stress (MS) from dental occlusion or orthodontic tooth movement. Mechanical stress is thought to be a trigger for remodeling of the PDL and alveolar bone, although its signaling mechanism is still unclear. So we investigated the effect of MS on adenosine triphosphate (ATP) release and extracellular signal-regulated kinases (ERK) phosphorylation in PDL cells. Mechanical stress was applied to human PDL cells as centrifugation-mediated gravity loading. Apyrase, Ca(2+)-free medium and purinergic receptor agonists and antagonists were utilized to analyze the contribution of purinergic receptors to ERK phosphorylation. Gravity loading and ATP increased ERK phosphorylation by 5 and 2.5 times, respectively. Gravity loading induced ATP release from PDL cells by tenfold. Apyrase and suramin diminished ERK phosphorylation induced by both gravity loading and ATP. Under Ca(2+)-free conditions the phosphorylation by gravity loading was partially decreased, whereas ATP-induced phosphorylation was unaffected. Receptors P2Y4 and P2Y6 were prominently expressed in the PDL cells. Gravity loading induced ATP release and ERK phosphorylation in PDL fibroblasts, and ATP signaling via P2Y receptors was partially involved in this phosphorylation, which in turn would enhance gene expression for the remodeling of PDL tissue during orthodontic tooth movement. © 2013 Wiley Publishing Asia Pty Ltd.

  2. Interlaboratory validation of the modified murine local lymph node assay based on adenosine triphosphate measurement.

    Science.gov (United States)

    Omori, Takashi; Idehara, Kenji; Kojima, Hajime; Sozu, Takashi; Arima, Kazunori; Goto, Hirohiko; Hanada, Tomohiko; Ikarashi, Yoshiaki; Inoda, Taketo; Kanazawa, Yukiko; Kosaka, Tadashi; Maki, Eiji; Morimoto, Takashi; Shinoda, Shinsuke; Shinoda, Naoki; Takeyoshi, Masahiro; Tanaka, Masashi; Uratani, Mamoru; Usami, Masahito; Yamanaka, Atsushi; Yoneda, Tomofumi; Yoshimura, Isao; Yuasa, Atsuko

    2008-01-01

    The murine local lymph node assay (LLNA) is a well-established alternative to the guinea pig maximization test (GPMT) or Buehler test (BT) for the assessment of the skin sensitizing ability of drugs and chemicals. Daicel Chemical Industries Ltd. has developed a modified LLNA based on the adenosine triphosphate (ATP) content (LLNA-DA). We conducted 2 interlaboratory validation studies to evaluate the reliability and relevance of LLNA-DA. The experiment involved 17 laboratories, wherein 14 chemicals were examined under blinded conditions. In the first study, 3 chemicals were examined in 10 laboratories and the remaining 9 were examined in 3 laboratories. In the second study, 1 chemical was examined in 7 laboratories and the remaining 4 chemicals were examined in 4 laboratories. The data were expressed as the ATP content for each chemical-treated group, and the stimulation index (SI) for each chemical-treated group was determined as the increase in the ATP content relative to the concurrent vehicle control group. An SI of 3 was set as the cut-off value for exhibiting skin sensitization activity. The results of the first study obtained in the experiments conducted for the 3 chemicals that were examined in all the 10 laboratories and for 5 of the remaining 9 chemicals were sufficiently consistent with small variations in their SI values. The sensitivity, specificity, and accuracy of LLNA-DA against those of GPMT/BT were 7/8 (87.5%), 3/3 (100%), and 10/11 (90.9%), respectively. In the second study, all the 5 chemicals studied demonstrated acceptably small interlaboratory variations. In the first study, a large variation was observed for 2 chemicals; in the second study, this variation was small. It was attributed to the application of dimethylsulfoxide as the solvent for the metallic salts. In conclusion, these 2 studies provide good evidence for the reliability of the LLNA-DA.

  3. Role of hemolysis in red cell adenosine triphosphate release in simulated exercise conditions in vitro.

    Science.gov (United States)

    Mairbäurl, Heimo; Ruppe, Florian A; Bärtsch, Peter

    2013-10-01

    Specific adenosine triphosphate (ATP) release from red blood cells has been discussed as a possible mediator controlling microcirculation in states of decreased tissue oxygen. Because intravascular hemolysis might also contribute to plasma ATP, we tested in vitro which portion of ATP release is due to hemolysis in typical exercise-induced strains to the red blood cells (shear stress, deoxygenation, and lactic acidosis). Human erythrocytes were suspended in dextran-containing media (hematocrit 10%) and were exposed to shear stress in a rotating Couette viscometer at 37°C. Desaturation (oxygen saturation of hemoglobin ∼20%) was achieved by tonometry with N2 before shear stress exposure. Cells not exposed to shear stress were used as controls. Na lactate (15 mM), lactic acid (15 mM, pH 7.0), and HCl (pH 7.0) were added to simulate exercise-induced lactic acidosis. After incubation, extracellular hemoglobin was measured to quantify hemolysis. ATP was measured with the luciferase assay. Shear stress increased extracellular ATP in a stress-related and time-dependent manner. Hypoxia induced a ∼10-fold increase in extracellular ATP in nonsheared cells and shear stress-exposed cells. Lactic acid had no significant effect on ATP release and hemolysis. In normoxic cells, approximately 20%-50% of extracellular ATP was due to hemolysis. This proportion decreased to less than 10% in hypoxic cells. Our results indicate that when exposing red blood cells to typical strains they encounter when passing through capillaries of exercising skeletal muscle, ATP release from red blood cells is caused mainly by deoxygenation and shear stress, whereas lactic acidosis had only a minor effect. Hemolysis effects were decreased when hemoglobin was deoxygenated. Together, by specific release and hemolysis, extracellular ATP reaches values that have been shown to cause local vasodilatation.

  4. Prolonged maintenance of 2,3-diphosphoglycerate acid and adenosine triphosphate in red blood cells during storage.

    Science.gov (United States)

    de Korte, Dirk; Kleine, Mya; Korsten, Herbert G H; Verhoeven, Arthur J

    2008-06-01

    Current additive solutions (ASs) for red cells (RBCs) do not maintain a constant level of critical metabolites such as adenosine triphosphate (ATP) and 2,3-diphosphoglycerate acid (2,3-DPG) during cold storage. From the literature it is known that the intracellular pH is an important determinant of RBC metabolism. Therefore, a new, alkaline, AS was developed with the aim to allow cold storage of RBCs with stable product characteristics. Whole blood-derived RBCs (leukoreduced) were resuspended in experimental medium phosphate-adenine-guanosine-glucose-gluconate-mannitol (PAGGG-M; pH 8.2) with and without washing in the same medium. During cold storage several in vitro variables, such as intracellular pH, 2,3-DPG, ATP, and hemolysis, were analyzed. During cold storage, RBCs resuspended in PAGGG-M showed a constant ATP level (approx. 6 mumol/g Hb) and a very limited hemolysis (level), followed by a slow decrease, with at Day 35 still 100 percent of the initial level. RBCs washed in PAGGG-M even showed a continuous increase of 2,3-DPG during 35 days, with a maximum level of 200 percent of the initial value. The effect of PAGGG-M appears to be related to long-lasting effects of the initial intracellular pH shortly after production. Resuspension of RBCs in our alkaline medium PAGGG-M resulted in a RBC unit of high quality during storage for up to at least 35 days, with 2,3-DPG levels of higher than 10 mumol per g Hb, hemolysis of less than 0.2 percent, and ATP levels of higher than 5 mumol per g Hb.

  5. A High Affinity Adenosine Kinase from Anopheles gambiae

    Science.gov (United States)

    Cassera, María B.; Ho, Meng-Chiao; Merino, Emilio F.; Burgos, Emmanuel S.; Rinaldo-Matthis, Agnes; Almo, Steven C.; Schramm, Vern L.

    2011-01-01

    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 (Km 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 Ap4A (2.0 Å resolution) reveals interactions for adenosine, ATP and the geometry for phosphoryl transfer. The polyphosphate charge is partly neutralized by a bound Mg2+ ion and an ion pair to a catalytic site Arg. The AgAK structure consists of a large catalytic core in a three-layered α/β/α sandwich, and a small cap domain in contact with adenosine. The specificity and tight-binding for adenosine arises 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 human adenosine kinase (48% identity) than to AK from Toxoplasma gondii (31% identity). With this extraordinary affinity for AgAK, adenosine is efficiently captured and converted to AMP at near the diffusion limit, suggesting an important role of this enzyme to maintain the adenine nucleotide pool. mRNA analysis verifies that AgAK transcripts are produced in the adult insects. PMID:21247194

  6. 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.

  7. Determination of adenosine phosphates in rat gastrocnemius at various postmortem intervals using high performance liquid chromatography.

    Science.gov (United States)

    Huang, Hong; Yan, Youyi; Zuo, Zhong; Yang, Lin; Li, Bin; Song, Yu; Liao, Linchuan

    2010-09-01

    Although the change in adenosine phosphate levels in muscles may contribute to the development of rigor mortis, the relationship between their levels and the onset and development of rigor mortis has not been well elucidated. In the current study, levels of the adenosine phosphates including adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP) in gastrocnemius at various postmortem intervals of 180 rats from different death modes were detected by high performance liquid chromatography. The results showed that the levels of ATP and ADP significantly decreased along with the postmortem period of rats from different death mode whereas the AMP level remained the same. In addition, it was found that changes in the ATP levels in muscles after death correlated well with the development of rigor mortis. Therefore, the ATP level could serve as a reference parameter for the deduction of rigor mortis in forensic science.

  8. Feasibility of gadoxetate disodium-enhanced MR cholangiography in chronic cholestatic biliary disease

    International Nuclear Information System (INIS)

    Kühn, J.-P.; Spoerl, M.; Nassif, A.; Mester, M.; Weitschies, W.; Siegmund, W.; Hosten, N.; Mensel, B.

    2014-01-01

    Aim: To investigate the feasibility of gadoxetate disodium-enhanced magnetic resonance (MR) cholangiography in chronic obstructive cholestatic biliary disease in the clinical setting. Materials and methods: Twenty-three patients with dilated bile duct trees and ten volunteers underwent gadoxetate disodium-enhanced liver MR cholangiography and were enrolled in the present retrospective study. Gadoxetate disodium was given in a standardized manner as a bolus injection at a dose of 0.25 mmol/kg of body weight (0.1 ml/kg). Region of interest-based measurement of mean enhancement of the dilated bile ducts was performed in series before gadoxetate disodium administration and during hepatobiliary phases. Results: Direct comparison of mean bile duct enhancement during hepatobiliary phases in the clinical imaging window between healthy volunteers [4.7 ± 2.2 arbitrary units (au)] and patients with dilated bile ducts (0.1 ± 0.3 au) revealed significantly lower or absent enhancement in dilated bile ducts (p = 0.001). Conclusion: Standard clinical gadoxetate disodium-enhanced MR cholangiography is not a reliable technique for the evaluation of the biliary trees, because of altered biliary gadoxetate disodium elimination in patients with chronic obstructive biliary diseases. - Highlights: • Biliary excretion of gadoxetic disodium is impaired in subjects with chronic central or segmental bile duct obstruction. • MR cholangiography using gadoxetic disodium is not feasible in patients with chronic cholestatic bile duct disease. • Gadoxetic disodium enhanced MRI is a potential biomarker to measure hepatobiliary transporter function

  9. Mechanism of action of minoxidil in the treatment of androgenetic alopecia is likely mediated by mitochondrial adenosine triphosphate synthase-induced stem cell differentiation.

    Science.gov (United States)

    Goren, A; Naccarato, T; Situm, M; Kovacevic, M; Lotti, T; McCoy, J

    2017-01-01

    Topical minoxidil is the only topical drug approved by the US Food and Drug Administration (FDA) for the treatment of androgenetic alopecia. However, the exact mechanism by which minoxidil stimulates anagen phase and promotes hair growth is not fully understood. In the late telegen phase of the hair follicle growth cycle, stem cells located in the bulge region differentiate and re-enter anagen phase, a period of growth lasting 2-6 years. In androgenetic alopecia, the anagen phase is shortened and a progressive miniaturization of hair follicles occurs, eventually leading to hair loss. Several studies have demonstrated that minoxidil increases the amount of intracellular Ca2+, which has been shown to up-regulate the enzyme adenosine triphosphate (ATP) synthase. A recent study demonstrated that ATP synthase, independent of its role in ATP synthesis, promotes stem cell differentiation. As such, we propose that minoxidil induced Ca2+ influx can increase stem cell differentiation and may be a key factor in the mechanism by which minoxidil facilitates hair growth. Based on our theory, we provide a roadmap for the development of a new class of drugs for the treatment of androgenetic alopecia.

  10. Inotropic responses of the frog ventricle to adenosine triphosphate and related changes in endogenous cyclic nucleotides.

    Science.gov (United States)

    Flitney, F W; Singh, J

    1980-07-01

    1. A study has been made of a well documented but poorly understood response of the isolated frog ventricle to treatment with exogenous adenosine 5' triphosphate (ATP). Measurements of membrane potential, isometric twitch tension and levels of endogenous 3',5'-cyclic nucleotides have been made at various times during the ATP-induced response. 2. ATP elicits a characteristic triphasic response, which comprises an initial, abrupt increase in contractility, rising to a maximum within a few beats (first phase); followed by a period when the twitch amplitude falls, sometimes to below the control level (second phase); and superceded by a more slowly developing and longer-lasting increase in contractile force (third phase). The response is unaffected by atropine, propranolol or phentolamine. However, the prostaglandin synthetase inhibitor indomethacin depresses the first phase and entirely suppresses the third phase. 3. The inotropic effects of ATP are accompanied by changes in the shape of the action potential. These effects are dose-related. The duration of the action potential (D-30mV) and its positive overshoot (O) are increased during all phases of the response, for [ATP]o's up to 10(-5) M. However, at higher [ATP]o's, D-30mV and O ar both reduced during the second phase (but not the first or third phase), when isometric twitch tension is also depressed. The relationship between action potential duration and twitch tension (P) for different [ATP]o's is linear for all three phases of the response, but the slopes of the curves (delta P/delta D) are markedly different, indicating that the sensitivity of the contractile system to membrane depolarization is not constant, but varies continuously throughout the response. 4. ATP has a potent stimulatory effect on the metabolism of endogenous 3',5'-cyclic nucleotides. The time courses of the changes in adenosine 3','5-cyclic monophosphate (3',5'-cyclic AMP) and guanosine 3',5'-cyclic monophosphate (3',5'-cyclic GMP) are

  11. [A prospective study of adenosine triphosphate-tumor chemosensitivity assay directed chemotherapy in patients with recurrent ovarian cancer].

    Science.gov (United States)

    Gao, Yu-tao; Wu, Ling-ying; Zhang, Wei; Zhao, Dan; Li, Ning; Tian, Hai-mei; Wang, Xiao-bing; Li, Mo; Sun, Yang-chun; Li, Nan; Li, Xiao-guang

    2013-05-01

    To investigate the efficacy of adenosine triphosphate (ATP)-tumor chemosensitivity assay (TCA) directed chemotherapy in patients with recurrent epithelial ovarian cancer. From August 2010 to June 2012, recurrent epithelial ovarian cancer patients were prospectively enrollmented in Cancer Hospital, Peking Union Medical College,Chinese Academy of Medical Sciences.The entry criteria are as follows: (1) Histologically proven to be epithelial ovarian cancer. (2) Patients of recurrent ovarian cancer with bidimensionally measurable tumor, or ascitic or pleural fluid for testing. (3) Karnofsky performance status > 60. (4) A life expectancy of at least more than 6 months.According to patients desires, they were assigned into two groups: assay-directed therapy group and physician's-choice therapy group, patients' clinical and pathological characteristics, response rate to chemotherapy and progression-free survival (PFS) were compared between two groups. A total of 113 patients with recurrent epithelial ovarian cancer were prospectively enrollmented to assay-directed chemotherapy (n = 56) or physician's-choice chemotherapy (n = 57).There was no difference in median age,types of recurrence, surgical-pathological stage, pathological type, tumor grade, times of recurrence, residual disease at secondary cytoreductive surgery between assay-directed group and physician's-choice group. The overall response rate (ORR) and median PFS in the ATP-TCA group was 66% (37/56) and 7 months, while the ORR in the control group was 46% (26/57, P = 0.037), the median PFS was 4 months (P = 0.040). For platinum-resistant patients, the ORR between ATP-TCA directed chemotherapy 59% (16/27) and control group 25% (7/28) were significantly different (P = 0.010), and the median PFS between two groups were also significantly different (5 months and 2 months, respectively, P = 0.003). ATP-TCA directed chemotherapy could improve ORR and PFS in patients with recurrent epithelial ovarian cancer, especially

  12. Comparison of myocardial blood flow induced by adenosine triphosphate and dipyridamole in patients with coronary artery disease

    International Nuclear Information System (INIS)

    Mamede, M.; Tadamura, Eiji; Hosokawa, Ryohei

    2005-01-01

    Myocardial perfusion imaging with adenosine triphosphate (ATP) has been used increasingly to diagnose coronary artery disease (CAD) and assess risk for this disease. This study compared absolute myocardial blood flow (MBF) and myocardial flow reserve index (MFR) with ATP and dipyridamole (DIP) in patients with CAD. MBF was quantified by 15 O-H 2 O PET in 21 patients with CAD (17 male, 4 female), aged 55 to 81 years. MBF was measured at rest, during intravenous injection of ATP (0.16 mg/kg/min), and again after DIP infusion (0.56 mg/kg). Regions of interest were drawn in nonischemic and ischemic segments based on findings from thallium-201 ( 201 Tl) scintigraphy and coronary angiography (CAG). Absolute MBF values and indexes of MFR were calculated in nonischemic and ischemic segments. Intravenous injection of ATP and DIP significantly increased MBF in nonischemic (2.4±0.9 and 2.1±0.8 ml/g/min, respectively; p<0.01, for both) and in ischemic segments (1.3±0.4 and 1.5±0.4 ml/g/min, respectively; p<0.01, for both). There was a significant difference in MBF values between ATP and DIP in nonischemic segments (p<0.05), which was not observed in ischemic segments. In nonischemic segments, ATP produced higher MFR than DIP (2.1±0.8 and 1.8±0.7, respectively; p<0.05), while no significant difference was observed in ischemic segments (1.5±0.6 and 1.7±0.3, respectively). ATP produced a greater hyperemia than DIP between the ischemic and nonischemic myocardium in patients with CAD. ATP is as effective as DIP for the diagnosis of CAD. (author)

  13. An incubation medium for the elevation of adenosine triphosphate and 2,3-diphosphoglycerate in fresh and long-preserved human erythrocytes.

    Science.gov (United States)

    Rubinstein, D; Warrendorf, E

    1975-06-01

    The levels of adenosine triphosphate (ATP) and 2,3-diphosphoglycerate in freshly drawn human erythrocytes can be tripled by a 2 h incubation at 37 degrees C in a medium containing 21 mM glucose, 1.8 mM adenine, 5 mM pyruvate, 10 mM inosine, and 96 mM phosphate. Similar incubation conditions will restore the levels of ATP and 2,3-diphosphoglycerate in erythrocytes from blood levels preserved for 12 and 15 weeks, respectively, to those of fresh cells. Omission of pyruvate from the incubation medium further increases the level of ATP slightly, but there is little elevation of 2,3-diphosphoglycerate. Under these conditions labelled pyruvate and lactate production from [14-C]glucose or [14-C]inosine is not diminished, but labelled fructose 1,6-diphosphate, rather than 2,3-diphosphoglycerate, accumulates. In addition, omission of pyruvate from the incubation medium, with a concomitant decrease in accumulation of 2,3-diphosphoglycerate, diminishes the concentration of inorganic phosphate required for optimal ATP elevation. A 5 h incubation in the glucose-adenine-pyruvate-inosine-phosphate medium elevates the levels of ATP and 2,3-diphosphoglycerate in erythrocytes from blood preserved in the cold for 15 weeks to twice that of fresh cells, indicating that the cells retain their metabolic potential even after prolonged storage at 2 degrees C. The medium may provide a method of rejuvenating 10-12 week cold-preserved erythrocytes for transfusion purposes, by a 1 h incubation at 37 degrees C.

  14. 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.

  15. Extracellular adenosine generation in the regulation of pro-inflammatory responses and pathogen colonization.

    Science.gov (United States)

    Alam, M Samiul; Costales, Matthew G; Cavanaugh, Christopher; Williams, Kristina

    2015-05-05

    Adenosine, an immunomodulatory biomolecule, is produced by the ecto-enzymes CD39 (nucleoside triphosphate dephosphorylase) and CD73 (ecto-5'-nucleotidase) by dephosphorylation of extracellular ATP. CD73 is expressed by many cell types during injury, infection and during steady-state conditions. Besides host cells, many bacteria also have CD39-CD73-like machinery, which helps the pathogen subvert the host inflammatory response. The major function for adenosine is anti-inflammatory, and most recent research has focused on adenosine's control of inflammatory mechanisms underlying various autoimmune diseases (e.g., colitis, arthritis). Although adenosine generated through CD73 provides a feedback to control tissue damage mediated by a host immune response, it can also contribute to immunosuppression. Thus, inflammation can be a double-edged sword: it may harm the host but eventually helps by killing the invading pathogen. The role of adenosine in dampening inflammation has been an area of active research, but the relevance of the CD39/CD73-axis and adenosine receptor signaling in host defense against infection has received less attention. Here, we review our recent knowledge regarding CD73 expression during murine Salmonellosis and Helicobacter-induced gastric infection and its role in disease pathogenesis and bacterial persistence. We also explored a possible role for the CD73/adenosine pathway in regulating innate host defense function during infection.

  16. 40 CFR 721.7000 - Polymer of disodium maleate, allyl ether, and ethylene oxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polymer of disodium maleate, allyl... New Uses for Specific Chemical Substances § 721.7000 Polymer of disodium maleate, allyl ether, and... substance identified generically as a polymer of disodium maleate, allyl ether, and ethylene oxide (P-91...

  17. The opposing effects of calmodulin, adenosine 5 prime -triphosphate, and pertussis toxin on phorbol ester induced inhibition of atrial natriuretic factor stimulated guanylate cyclase in SK-NEP-1 cells

    Energy Technology Data Exchange (ETDEWEB)

    Sekiya, M.; Frohlich, E.D.; Cole, F.E. (Alton Ochsner Medical Foundation, New Orleans, LA (USA))

    1991-01-01

    In the present study, we investigated the effects of calmodulin, adenosine 5{prime}-triphosphate (ATP) and pertussis toxin (PT) on phorbol ester (PMA) induced inhibition of ANF-stimulated cyclic GMP formation in cells from the human renal cell line, SK-NEP-1. PMA inhibited ANF-stimulated guanylate cyclase activity in particulate membranes by about 65%. Calmodulin reversed this inhibition in a dose dependent manner. ATP potentiated Mg++ but not Mn++ supported guanylate cyclase activity. In PMA treated membranes, ATP potentiating effects were abolished. PMA also inhibited ANF-stimulated cGMP accumulation, but pretreatment with PT prevented this PMA inhibition. PT did not affect basal or ANF-stimulated cGMP accumulation. In conclusion, these results demonstrated that PMA inhibited ANF stimulation of particulate guanylate cyclase in opposition to the activating effects of calmodulin or ATP in SK-NEP-1 cells. The protein kinase C inhibitory effects appeared to be mediated via a PT-sensitive G protein.

  18. Troubleshooting arterial-phase MR images of gadoxetate disodium-enhanced liver

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Ji Mi; Kim, So Yeon; Lee, Seung Soo; Kim, Kyoung Won [Dept. of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Yeh, Benjamin M.; Wang, Z. Jane [Dept. of Radiologyand Biomedical Imaging, University of California San Francisco, San Francisco (United States); Wu, En Haw [Dept. of Medical Imaging and Intervention, Chang Gung Memorial Hospital, Linkou and Chang Gung University College of Medicine, Taoyuan (China); Zhao, Li Qin [Beijing Friendship Hospital, Capital Medical University, Beijing (China); Chang, Wei Chou [Tri-Service General Hospital and National Defense Medical Center, Taipei (China)

    2015-12-15

    Gadoxetate disodium is a widely used magnetic resonance (MR) contrast agent for liver MR imaging, and it provides both dynamic and hepatobiliary phase images. However, acquiring optimal arterial phase images at liver MR using gadoxetate disodium is more challenging than using conventional extracellular MR contrast agent because of the small volume administered, the gadolinium content of the agent, and the common occurrence of transient severe motion. In this article, we identify the challenges in obtaining high-quality arterial-phase images of gadoxetate disodium-enhanced liver MR imaging and present strategies for optimizing arterial-phase imaging based on the thorough review of recent research in this field.

  19. Troubleshooting arterial-phase MR images of gadoxetate disodium-enhanced liver

    International Nuclear Information System (INIS)

    Huh, Ji Mi; Kim, So Yeon; Lee, Seung Soo; Kim, Kyoung Won; Yeh, Benjamin M.; Wang, Z. Jane; Wu, En Haw; Zhao, Li Qin; Chang, Wei Chou

    2015-01-01

    Gadoxetate disodium is a widely used magnetic resonance (MR) contrast agent for liver MR imaging, and it provides both dynamic and hepatobiliary phase images. However, acquiring optimal arterial phase images at liver MR using gadoxetate disodium is more challenging than using conventional extracellular MR contrast agent because of the small volume administered, the gadolinium content of the agent, and the common occurrence of transient severe motion. In this article, we identify the challenges in obtaining high-quality arterial-phase images of gadoxetate disodium-enhanced liver MR imaging and present strategies for optimizing arterial-phase imaging based on the thorough review of recent research in this field

  20. Phosphorus Partitioning of Soybean Lines Containing Different Mutant Alleles of Two Soybean Seed-Specific Adenosine Triphosphate-Binding Cassette Phytic Acid Transporter Paralogs

    Directory of Open Access Journals (Sweden)

    Jason D. Gillman

    2013-03-01

    Full Text Available Seed phytate is a repository of P and minerals in soybean [ (L. Merr.] seeds that limits P and mineral bioavailability for monogastric animals (e.g., humans, swine [], and poultry [especially chicken, ] due to insufficient digestive tract phytase activity. We previously identified epistatic recessive mutations affecting two paralogous adenosine triphosphate-binding cassette phytic acid transporter genes (one a nonsense mutation in and the other a missense mutation in as the molecular genetic basis in the ethyl methanesulfonate (EMS-induced mutant low phytate soybean line M153. An additional mutant low phytate line, M766, contained one single nucleotide polymorphism within the ninth intron of the locus as well as a nonsense mutation in . The objectives of this research were to clarify the genetics underlying the low phytate phenotype in line M766 and to determine P partitioning in new combinations of mutant alleles from M766 and M153. Inheritance of nonsense alleles affecting both ( genes (one from M153 and one from M766 led to the production of viable seeds that contained transgressive reductions in total seed phytate and significantly higher levels of inorganic phosphate than has been reported for nontransgenic soybean material and will allow efficient molecular selection of soybeans with even greater reductions of phytate for improved quality soybean meal.

  1. 5' adenosine monophosphate-activated protein kinase, metabolism and exercise.

    Science.gov (United States)

    Aschenbach, William G; Sakamoto, Kei; Goodyear, Laurie J

    2004-01-01

    The 5' adenosine monophosphate-activated protein kinase (AMPK) is a member of a metabolite-sensing protein kinase family that functions as a metabolic 'fuel gauge' in skeletal muscle. AMPK is a ubiquitous heterotrimeric protein, consisting of an alpha catalytic, and beta and gamma regulatory subunits that exist in multiple isoforms and are all required for full enzymatic activity. During exercise, AMPK becomes activated in skeletal muscle in response to changes in cellular energy status (e.g. increased adenosine monophosphate [AMP]/adenosine triphosphate [ATP] and creatine/phosphocreatine ratios) in an intensity-dependent manner, and serves to inhibit ATP-consuming pathways, and activate pathways involved in carbohydrate and fatty-acid metabolism to restore ATP levels. Recent evidence shows that although AMPK plays this key metabolic role during acute bouts of exercise, it is also an important component of the adaptive response of skeletal muscles to endurance exercise training because of its ability to alter muscle fuel reserves and expression of several exercise-responsive genes. This review discusses the putative roles of AMPK in acute and chronic exercise responses, and suggests avenues for future AMPK research in exercise physiology and biochemistry.

  2. Monitoring of intracellular adenosine triphosphate in CD4(+) T cells to predict the occurrence of cytomegalovirus disease in kidney transplant recipients.

    Science.gov (United States)

    Pérez-Jacoiste Asín, María Asunción; Fernández-Ruiz, Mario; López-Medrano, Francisco; Aquilino, Carolina; González, Esther; Ruiz-Merlo, Tamara; Gutiérrez, Eduardo; San Juan, Rafael; Paz-Artal, Estela; Andrés, Amado; Aguado, José Maria

    2016-10-01

    The measurement of intracellular concentrations of adenosine triphosphate (iATP) in phytohemagglutinin-stimulated CD4(+) T cells constitutes a surrogate marker for post-transplant cell-mediated immunity (CMI). This assay has shown suboptimal accuracy for predicting infection after kidney transplantation (KT). We hypothesize that its predictive capacity depends on the specific contribution of the CMI to host-pathogen interactions. We assessed iATP levels in 100 KT recipients at baseline and months 1, 3, and 6 (363 measurements). No association was found between iATP at month 1 and the risk for overall or bacterial infection, although such association was evident for cytomegalovirus (CMV) disease (multivariate-adjusted hazard ratio [per 50-unit increment]: 0.83; P-value = 0.048). There were no significant differences in mean iATP between stable patients (319.4 ng/ml) and those developing overall (304.1 ng/ml) or bacterial infection (346.9 ng/ml) over the 45 days following monitoring. However, iATP was significantly lower in patients who developed CMV disease (223.5 ng/ml; P-values <0.002). The optimal cutoff (265 ng/ml) for predicting CMV disease in patients not receiving antiviral prophylaxis yielded sensitivity, specificity, positive, and negative predictive values of 85.7%, 68.3%, 15.2%, and 98.6%, respectively. In conclusion, a non-pathogen-specific monitoring of CMI by means of iATP informs the risk of CMV disease in KT recipients. © 2016 Steunstichting ESOT.

  3. Visual and surface plasmon resonance sensor for zirconium based on zirconium-induced aggregation of adenosine triphosphate-stabilized gold nanoparticles

    International Nuclear Information System (INIS)

    Qi, Wenjing; Zhao, Jianming; Zhang, Wei; Liu, Zhongyuan; Xu, Min; Anjum, Saima; Majeed, Saadat; Xu, Guobao

    2013-01-01

    Graphical abstract: Visual and surface plasmon resonance (SPR) sensor for Zr(IV) has been developed for the first time based on Zr(IV)-induced change of SPR absorption spectra of ATP-stabilized AuNP solutions. -- Highlights: •Visual and SPR absorption Zr 4+ sensors have been developed for the first time. •The high affinity between Zr 4+ and ATP makes sensor highly sensitive and selective. •A fast response to Zr 4+ within 4 min. -- Abstract: Owing to its high affinity with phosphate, Zr(IV) can induce the aggregation of adenosine 5′-triphosphate (ATP)-stabilized AuNPs, leading to the change of surface plasmon resonance (SPR) absorption spectra and color of ATP-stabilized AuNP solutions. Based on these phenomena, visual and SPR sensors for Zr(IV) have been developed for the first time. The A 660 nm /A 518 nm values of ATP-stabilized AuNPs in SPR absorption spectra increase linearly with the concentrations of Zr(IV) from 0.5 μM to 100 μM (r = 0.9971) with a detection limit of 95 nM. A visual Zr(IV) detection is achieved with a detection limit of 30 μM. The sensor shows excellent selectivity against other metal ions, such as Cu 2+ , Fe 3+ , Cd 2+ , and Pb 2+ . The recoveries for the detection of 5 μM, 10 μM, 25 μM and 75 μM Zr(IV) in lake water samples are 96.0%, 97.0%, 95.6% and 102.4%, respectively. The recoveries of the proposed SPR method are comparable with those of ICP-OES method

  4. 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

    2014-08-07

    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.

  5. On the use of X-ray absorption spectroscopy to elucidate the structure of lutetium adenosine mono- and triphosphate complexes.

    Science.gov (United States)

    Mostapha, S; Berthon, C; Fontaine-Vive, F; Gaysinski, M; Guérin, L; Guillaumont, D; Massi, L; Monfardini, I; Solari, P L; Thomas, O P; Charbonnel, M C; Den Auwer, C

    2014-02-01

    Although the physiological impact of the actinide elements as nuclear toxicants has been widely investigated for half a century, a description of their interactions with biological molecules remains limited. It is however of primary importance to better assess the determinants of actinide speciation in cells and more generally in living organisms to unravel the molecular processes underlying actinide transport and deposition in tissues. The biological pathways of this family of elements in case of accidental contamination or chronic natural exposure (in the case of uranium rich soils for instance) are therefore a crucial issue of public health and of societal impact. Because of the high chemical affinity of those actinide elements for phosphate groups and the ubiquity of such chemical functions in biochemistry, phosphate derivatives are considered as probable targets of these cations. Among them, nucleotides and in particular adenosine mono- (AMP) and triphosphate (ATP) nucleotides occur in more chemical reactions than any other compounds on the earth's surface, except water, and are therefore critical target molecules. In the present study, we are interested in trans-plutonium actinide elements, in particular americium and curium that are more rarely considered in environmental and bioaccumulation studies than early actinides like uranium, neptunium and plutonium. A first step in this strategy is to work with chemical analogues like lanthanides that are not radioactive and therefore allow extended physical chemical characterization to be conducted that are difficult to perform with radioactive materials. We describe herein the interaction of lutetium(III) with adenosine AMP and ATP. With AMP and ATP, insoluble amorphous compounds have been obtained with molar ratios of 1:2 and 1:1, respectively. With an excess of ATP, with 1:2 molar ratio, a soluble complex has been obtained. A combination of spectroscopic techniques (IR, NMR, ESI-MS, EXAFS) together with quantum

  6. Crystal structures of T. b. rhodesiense adenosine kinase complexed with inhibitor and activator: implications for catalysis and hyperactivation.

    Directory of Open Access Journals (Sweden)

    Sabine Kuettel

    2011-05-01

    Full Text Available BACKGROUND: The essential purine salvage pathway of Trypanosoma brucei bears interesting catalytic enzymes for chemotherapeutic intervention of Human African Trypanosomiasis. Unlike mammalian cells, trypanosomes lack de novo purine synthesis and completely rely on salvage from their hosts. One of the key enzymes is adenosine kinase which catalyzes the phosphorylation of ingested adenosine to form adenosine monophosphate (AMP utilizing adenosine triphosphate (ATP as the preferred phosphoryl donor. METHODS AND FINDINGS: Here, we present the first structures of Trypanosoma brucei rhodesiense adenosine kinase (TbrAK: the structure of TbrAK in complex with the bisubstrate inhibitor P(1,P(5-di(adenosine-5'-pentaphosphate (AP5A at 1.55 Å, and TbrAK complexed with the recently discovered activator 4-[5-(4-phenoxyphenyl-2H-pyrazol-3-yl]morpholine (compound 1 at 2.8 Å resolution. CONCLUSIONS: The structural details and their comparison give new insights into substrate and activator binding to TbrAK at the molecular level. Further structure-activity relationship analyses of a series of derivatives of compound 1 support the observed binding mode of the activator and provide a possible mechanism of action with respect to their activating effect towards TbrAK.

  7. Poly(adenosine 5'-diphosphate) ribose polymerase activation as a cause of metabolic dysfunction in critical illness.

    Science.gov (United States)

    Liaudet, Lucas

    2002-03-01

    Poly(adenosine 5'-diphosphate) ribose polymerase is a nuclear enzyme activated in response to genotoxic stress induced by a variety of DNA damaging agents. Several oxygen and nitrogen-centered free radicals, notably peroxynitrite, are strong inducers of DNA damage and poly(adenosine 5'-diphosphate) ribose polymerase activation in vitro and in vivo. Activation of this nuclear enzyme depletes the intracellular stores of its substrate nicotinamide adenine dinucleotide, slowing the rate of glycolysis, mitochondrial electron transport and adenosine triphosphate formation. This process triggers a severe energetic crisis within the cell, leading to acute cell dysfunction and cell necrosis. Poly(adenosine 5'-diphosphate) ribose polymerase also plays an important role in the regulation of inflammatory cascades, through a functional association with various transcription factors and transcription co-activators. Recent works identified this enzyme as a critical mediator of cellular metabolic dysfunction, inflammatory injury, and organ damage in conditions associated with overwhelming oxidative stress, including systemic inflammation, circulatory shock, and ischemia-reperfusion. Accordingly, pharmacological inhibitors of poly(adenosine 5'-diphosphate) ribose polymerase protect against cell death and tissue injury in such conditions, and may therefore represent novel therapeutic tools to limit multiple organ damage and dysfunction in critically ill patients.

  8. Reconsideration of the sequence of rigor mortis through postmortem changes in adenosine nucleotides and lactic acid in different rat muscles.

    Science.gov (United States)

    Kobayashi, M; Takatori, T; Iwadate, K; Nakajima, M

    1996-10-25

    We examined the changes in adenosine triphosphate (ATP), lactic acid, adenosine diphosphate (ADP) and adenosine monophosphate (AMP) in five different rat muscles after death. Rigor mortis has been thought to occur simultaneously in dead muscles and hence to start in small muscles sooner than in large muscles. In this study we found that the rate of decrease in ATP was significantly different in each muscle. The greatest drop in ATP was observed in the masseter muscle. These findings contradict the conventional theory of rigor mortis. Similarly, the rates of change in ADP and lactic acid, which are thought to be related to the consumption or production of ATP, were different in each muscle. However, the rate of change of AMP was the same in each muscle.

  9. Adenosine Monophosphate (AMP)-Activated Protein Kinase: A New Target for Nutraceutical Compounds.

    Science.gov (United States)

    Marín-Aguilar, Fabiola; Pavillard, Luis E; Giampieri, Francesca; Bullón, Pedro; Cordero, Mario D

    2017-01-29

    Adenosine monophosphate-activated protein kinase (AMPK) is an important energy sensor which is activated by increases in adenosine monophosphate (AMP)/adenosine triphosphate (ATP) ratio and/or adenosine diphosphate (ADP)/ATP ratio, and increases different metabolic pathways such as fatty acid oxidation, glucose transport and mitochondrial biogenesis. In this sense, AMPK maintains cellular energy homeostasis by induction of catabolism and inhibition of ATP-consuming biosynthetic pathways to preserve ATP levels. Several studies indicate a reduction of AMPK sensitivity to cellular stress during aging and this could impair the downstream signaling and the maintenance of the cellular energy balance and the stress resistance. However, several diseases have been related with an AMPK dysfunction. Alterations in AMPK signaling decrease mitochondrial biogenesis, increase cellular stress and induce inflammation, which are typical events of the aging process and have been associated to several pathological processes. In this sense, in the last few years AMPK has been identified as a very interesting target and different nutraceutical compounds are being studied for an interesting potential effect on AMPK induction. In this review, we will evaluate the interaction of the different nutraceutical compounds to induce the AMPK phosphorylation and the applications in diseases such as cancer, type II diabetes, neurodegenerative diseases or cardiovascular diseases.

  10. Hybridization chain reaction-based colorimetric aptasensor of adenosine 5'-triphosphate on unmodified gold nanoparticles and two label-free hairpin probes.

    Science.gov (United States)

    Gao, Zhuangqiang; Qiu, Zhenli; Lu, Minghua; Shu, Jian; Tang, Dianping

    2017-03-15

    This work designs a new label-free aptasensor for the colorimetric determination of small molecules (adenosine 5'-triphosphate, ATP) by using visible gold nanoparticles as the signal-generation tags, based on target-triggered hybridization chain reaction (HCR) between two hairpin DNA probes. The assay is carried out referring to the change in the color/absorbance by salt-induced aggregation of gold nanoparticles after the interaction with hairpins, gold nanoparticles and ATP. To construct such an assay system, two hairpin DNA probes with a short single-stranded DNA at the sticky end are utilized for interaction with gold nanoparticles. In the absence of target ATP, the hairpin DNA probes can prevent gold nanoparticles from the salt-induced aggregation through the interaction of the single-stranded DNA at the sticky end with gold nanoparticles. Upon target ATP introduction, the aptamer-based hairpin probe is opened to expose a new sticky end for the strand-displacement reaction with another complementary hairpin, thus resulting in the decreasing single-stranded DNA because of the consumption of hairpins. In this case, gold nanoparticles are uncovered owing to the formation of double-stranded DNA, which causes their aggregation upon addition of the salt, thereby leading to the change in the red-to-blue color. Under the optimal conditions, the HCR-based colorimetric assay presents good visible color or absorbance responses for the determination of target ATP at a concentration as low as 1.0nM. Importantly, the methodology can be further extended to quantitatively or qualitatively monitor other small molecules or biotoxins by changing the sequence of the corresponding aptamer. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Effects of chronic digitalization on cardiac and renal Na+ + K+-dependent adenosine triphosphate activity and circulating catecholamines in the dog.

    Science.gov (United States)

    Nechay, B R; Jackson, R E; Ziegler, M G; Neldon, S L; Thompson, J D

    1981-09-01

    To extend our understanding of the mechanism of action of digitalis drugs, we studied electrocardiograms (ECGs), renal function, plasma concentrations of catecholamines, and myocardial and renal Na+ + K+-dependent adenosine triphosphate (Na+ + K+ ATPase) activity in chronically digitalized dogs. Five healthy, male, mongrel dogs received a therapeutic regimen of digoxin (0.1 mg/kg on day 1 in three divided doses followed by 0.025 mg/kg per day) orally for 2-4 months. This resulted in plasma digoxin concentrations of 1.1 to 4.7 ng/ml as determined by radioimmunoassay. Six control dogs received daily gelatin capsules by mouth. ECGs monitored throughout the study showed no changes. Digitalized dogs had elevated plasma norepinephrine concentrations (347 vs. 137 pg/ml in controls) and no change in plasma epinephrine concentrations. Digitalized dogs had elevated glomerular filtration rates (0.74 vs. 0.94 ml/min per g of kidney) without significant changes in renal handling of electrolytes and water. All of the above studies were done without the aid of restraining drugs or infusions. The animals were killed with an overdose of pentobarbital for in vitro studies. In digitalized dogs, microsomal Na+ + K+ ATPase-specific activity was 26 to 33% lower in the renal cortex, medulla, and papilla, and 46% lower in the cardiac left ventricle than in control dogs. Digitalization did not alter the osmolalities of renal tissues. We conclude that chronic reduction Na+ + K+ ATPase activity by one-third dose does not cause abnormalities in renal handling of electrolytes and water, and inhibition of Na+ + K+ ATPase in the left ventricular muscle by one-half is associated with no obvious ECG changes in the dog. Further, elevated plasma norepinephrine concentrations may contribute to both the therapeutic and the toxic effects of digitalis.

  12. 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.

  13. Adenosine triphosphate-based chemotherapy response assay (ATP-CRA)-guided platinum-based 2-drug chemotherapy for unresectable nonsmall-cell lung cancer.

    Science.gov (United States)

    Moon, Yong Wha; Choi, Sung Ho; Kim, Yong Tai; Sohn, Joo Hyuk; Chang, Joon; Kim, Se Kyu; Park, Moo Suk; Chung, Kyung Young; Lee, Hyoun Ju; Kim, Joo-Hang

    2007-05-01

    The study investigated correlations between adenosine triphosphate / chemotherapy response assay (ATP-CRA) and clinical outcomes after ATP-CRA-guided platinum-based chemotherapy for unresectable nonsmall-cell lung cancer (NSCLC). The authors performed an in vitro chemosensitivity test, ATP-CRA, to evaluate the chemosensitivities of anticancer drugs such as cisplatin, carboplatin, paclitaxel, docetaxel, gemcitabine, and vinorelbine for chemonaive, unresectable NSCLC. The cell death rate was determined by measuring the intracellular ATP levels of drug-exposed cells compared with untreated controls. A sensitive drug was defined as a drug producing 30% or more reduction in ATP compared with untreated controls. Assay-guided platinum-based 2-drug chemotherapy was given to patients with pathologically confirmed NSCLC. Thirty-four patients were enrolled. Thirty tumor specimens were obtained by bronchoscopic biopsies and 4 obtained surgically. The median age was 61 years and 27 patients had an Eastern Cooperative Oncology Group (ECOG) performance status of 0-1. The response rate was 43.8%. At a median follow-up period of 16.9 months, the median progression-free and overall survivals were 3.6 and 11.2 months, respectively. Patients were dichotomized into the platinum-sensitive (S; 20 patients) and resistant (R; 14 patients) groups. The positive/negative predictive values were 61.1% and 78.6% with a predictive accuracy of 68.8%. Although without significant differences in pretreatment parameters, the S-group showed better clinical response (P=.036), longer progression-free survival (P=.060), and longer overall survival (P=.025). Despite using bronchoscopic biopsied specimens, ATP-CRA and clinical outcomes correlated well after assay-guided platinum-based 2-drug chemotherapy for unresectable NSCLC. There was a favorable response and survival in the platinum-sensitive vs resistant groups. Copyright (c) 2007 American Cancer Society

  14. The effect of experimental gastric dilatation-volvulus on adenosine triphosphate content and conductance of the canine gastric and jejunal mucosa.

    Science.gov (United States)

    Peycke, Laura E; Hosgood, Giselle; Davidson, Jacqueline R; Tetens, Joanne; Taylor, H Wayne

    2005-07-01

    The objective of this study was to determine if experimental gastric dilatation volvulus (GDV) would decrease adenosine triphosphate (ATP) concentration and increase membrane conductance of the canine gastric and jejunal mucosa. Male dogs (n = 15) weighing between 20 and 30 kg were used. Dogs were randomly assigned to 1 of 3 equal groups: Group 1 was control, group 2 was GDV, and group 3 was ischemia. All dogs were anesthetized for 210 min. Group 1 had no manipulation. Group 2 had GDV experimentally induced for 120 min followed by decompression, derotation, and reperfusion for 90 min. Group 3 had GDV experimentally induced for 210 min. Gastric (fundus and pylorus) and jejunal tissue was taken at 0, 120, and 210 min from all of the dogs. Tissue was analyzed for ATP concentration, mucosal conductance, and microscopic changes. The ATP concentration in the fundus did not change significantly from baseline in group 2, but decreased significantly below baseline at 210 min in group 3. The ATP concentration in the jejunum decreased significantly below baseline in groups 2 and 3 at 120 min, remaining significantly decreased in group 3 but returning to baseline at 210 min in group 2. Mucosal conductance of the fundus did not change significantly in any dog. Mucosal conductance of the jejunum increased at 120 min in groups 2 and 3, and became significantly increased above baseline at 210 min. The jejunal mucosa showed more profound cellular changes than the gastric mucosa. The jejunum showed substantial decreases in ATP concentration with an increase in mucosal conductance, suggesting cell membrane dysfunction. Dogs sustaining a GDV are likely to have a change in the activity of mucosal cells in the jejunum, which may be important in the pathophysiology of GDV.

  15. 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

  16. 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.

    Science.gov (United States)

    Burger, Patrick; Korsten, Herbert; De Korte, Dirk; Rombout, Eva; Van Bruggen, Robin; Verhoeven, Arthur J

    2010-11-01

    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), both 2,3-DPG and ATP could be maintained throughout storage for 35 days. In this study, the mechanism underlying the effect of PAGGGM on RBC storage was studied in more detail. By using double-erythrocytapheresis units (leukoreduced), a direct comparison could be made between the current AS saline-adenine-glucose-mannitol (SAGM) and the experimental solution PAGGGM. During cold storage, several in vitro characteristics were analyzed. In agreement with our previous findings with single RBCs, PAGGGM maintained 2,3-DPG and ATP levels for 35 days of cold storage. Furthermore, glucose consumption and lactate production were higher in PAGGGM units during the first 21 days of cold storage. Fructose-1,6-diphophate and dihydroxyacetone phosphate levels were also increased during the first 21 days of storage in PAGGGM units. These results indicate that it is likely that phosphofructokinase (PFK) activity is enhanced in PAGGGM units relative to SAGM units. After 21 days, PFK activity also decreases in PAGGGM units, but sufficient metabolic reserve in these units prevents depletion of 2,3-DPG and ATP. © 2010 American Association of Blood Banks.

  17. Colorimetric sensor for triphosphates and their application as a viable staining agent for prokaryotes and eukaryotes.

    Science.gov (United States)

    Ghosh, Amrita; Shrivastav, Anupama; Jose, D Amilan; Mishra, Sanjiv K; Chandrakanth, C K; Mishra, Sandhya; Das, Amitava

    2008-07-15

    The chromogenic complex 1 x Zn (where 1 is (E)-4-(4-dimethylamino-phenylazo)-N,N-bispyridin-2-ylmethyl-benzenesulfonamide) showed high affinity toward the phosphate ion in tetrabutylammonium phosphate in acetonitrile solution and could preferentially bind to adenosine triphosphate (ATP) in aqueous solution at physiological pH. This binding caused a visual change in color, whereas no such change was noticed with other related anions (adenosine monophosphate, adenosine diphosphate, pyrophosphate, and phosphate) of biological significance. Thus, 1 x Zn could be used as a staining agent for different biological cells through binding to the ATP, generated in situ by the mitochondria (in eukaryotes). For prokaryotes (bacteria) the cell membrane takes care of the cells' energy conversion, since they lack mitochondria. ATP is produced in their unique cell structure on the cell membrane, which is not found in any eukaryotes. These stained cells could be viewed with normal light microscopy. This reagent could even be used for distinguishing the gram-positive and the gram-negative bacteria (prokaryotes). This dye was found to be nonlipophilic in nature and nontoxic to living microbes (eukaryotes and prokaryotes). Further, stained cells were found to grow in their respective media, and this confirmed the maintenance of viability of the microbes even after staining, unlike with many other dyes available commercially.

  18. 21 CFR 172.135 - Disodium EDTA.

    Science.gov (United States)

    2010-04-01

    ..., other than black-eyed peas) 165 Promote color retention. Mayonnaise 75 Preservative. Ready-to-eat cereal... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Disodium EDTA. 172.135 Section 172.135 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN...

  19. Regulation of Maltodextrin Phosphorylase Synthesis in Escherichia coli by Cyclic Adenosine 3′, 5′-Monophosphate and Glucose1

    Science.gov (United States)

    Chao, Julie; Weathersbee, Carolyn J.

    1974-01-01

    Cyclic adenosine 3′, 5′-monophosphate (AMP) stimulates maltodextrin phosphorylase synthesis in Escherichia coli cells induced with maltose. A maximal effect occurs at 2 to 3 mM cyclic AMP. The action of cyclic AMP is specific, inasmuch as adenosine triphosphate, 3′-AMP, 5′-AMP, adenosine, and dibutyryl cyclic AMP are inactive. Glucose, α-methyl glucoside, 2-deoxyglucose, and pyridoxal 5′-phosphate repress maltodextrin phosphorylase synthesis. This repression is reversed by cyclic AMP. The action of cyclic AMP appears to be at the transcriptional level, since cyclic AMP fails to stimulate phosphorylase production in induced cells in which messenger ribonucleic acid synthesis has been arrested by rifampin or by inducer removal. The two other enzymes involved in the metabolism of maltose, amylomaltase and maltose permease, are also induced in this strain of E. coli and affected by glucose and cyclic AMP in a manner similar to phosphorylase. PMID:4358043

  20. Comparison of transient severe motion in gadoxetate disodium and gadopentetate dimeglumine-enhanced MRI. Effect of modified breath-holding method

    International Nuclear Information System (INIS)

    Song, Ji Soo; Choi, Eun Jung; Park, Eun Hae; Lee, Ju-Hyung

    2018-01-01

    To compare the occurrence of transient severe motion (TSM) between gadoxetate disodium- and gadopentetate dimeglumine-enhanced MRI and between gadoxetate disodium-enhanced MRI scans obtained with and without the application of a modified breath-holding technique. We reviewed 80 patients who underwent two magnetic resonance examinations (gadoxetate disodium-enhanced MRI and gadopentetate dimeglumine-enhanced MRI) with the application of a modified breath-holding technique (dual group). This group was compared with 100 patients who underwent gadoxetate disodium-enhanced MRI without the application of the modified breath-holding technique (single group). Patient risk factors and motion scores (1 [none] to 5 [non-diagnostic]) for each dynamic-phase imaging were analysed. In the dual group, mean motion scores did not differ significantly between gadoxetate disodium- and gadopentetate dimeglumine-enhanced MRI (p=0.096-0.807) in any phase. However, in all phases except the late dynamic phase, mean motion scores of the dual group were significantly lower than those in the single group. TSM incidence did not differ significantly between gadoxetate disodium- and gadopentetate dimeglumine-enhanced MRI in the dual group (3.8% vs. 1.3%, p=0.620). With proper application of the modified breath-holding technique, TSM occurrence with gadoxetate disodium-enhanced MRI was comparable to that associated with gadopentetate dimeglumine-enhanced MRI. (orig.)

  1. Comparison of transient severe motion in gadoxetate disodium and gadopentetate dimeglumine-enhanced MRI. Effect of modified breath-holding method

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ji Soo; Choi, Eun Jung; Park, Eun Hae [Chonbuk National University Medical School and Hospital, Department of Radiology, Jeonju (Korea, Republic of); Research Institute of Clinical Medicine of Chonbuk National University, Jeonju (Korea, Republic of); Biomedical Research Institute of Chonbuk National University Hospital, Jeonju (Korea, Republic of); Lee, Ju-Hyung [Chonbuk National University Medical School, Department of Preventive Medicine, Jeonju (Korea, Republic of)

    2018-03-15

    To compare the occurrence of transient severe motion (TSM) between gadoxetate disodium- and gadopentetate dimeglumine-enhanced MRI and between gadoxetate disodium-enhanced MRI scans obtained with and without the application of a modified breath-holding technique. We reviewed 80 patients who underwent two magnetic resonance examinations (gadoxetate disodium-enhanced MRI and gadopentetate dimeglumine-enhanced MRI) with the application of a modified breath-holding technique (dual group). This group was compared with 100 patients who underwent gadoxetate disodium-enhanced MRI without the application of the modified breath-holding technique (single group). Patient risk factors and motion scores (1 [none] to 5 [non-diagnostic]) for each dynamic-phase imaging were analysed. In the dual group, mean motion scores did not differ significantly between gadoxetate disodium- and gadopentetate dimeglumine-enhanced MRI (p=0.096-0.807) in any phase. However, in all phases except the late dynamic phase, mean motion scores of the dual group were significantly lower than those in the single group. TSM incidence did not differ significantly between gadoxetate disodium- and gadopentetate dimeglumine-enhanced MRI in the dual group (3.8% vs. 1.3%, p=0.620). With proper application of the modified breath-holding technique, TSM occurrence with gadoxetate disodium-enhanced MRI was comparable to that associated with gadopentetate dimeglumine-enhanced MRI. (orig.)

  2. Extracellular Adenosine Triphosphate Associated with Amphibian Erythrocytes: Inhibition of ATP Release by Anion Channel Blockers.

    Science.gov (United States)

    1986-01-01

    Paddle and Burnstock (326), Williams and Forrester (463), Forrester and Williams (151) and Clemens and Forrester (82) provide evidence that hypoxia may...an ATp4 - receptor. Fed. Proc. 45:208, 1986. (abstr) 99. Dahlen , S.E. and Hedqvist, P. ATP, B,y-methylene ATP andN adenosine inhibit non-cholinergic...regulation of skeletal muscle blood low. Circ Res. 29:375-384, 1971. 117. Dodd, J., Jahr, C.E., Hamilton, P.N., Heath, M.J., Matthew , W.P., and Jessell, T.M

  3. Respiratory motion artefacts in dynamic liver MRI: a comparison using gadoxetate disodium and gadobutrol

    Energy Technology Data Exchange (ETDEWEB)

    Luetkens, Julian A.; Kupczyk, Patrick A.; Doerner, Jonas; Willinek, Winfried A.; Schild, Hans H.; Kukuk, Guido M. [University of Bonn, Department of Radiology, Bonn (Germany); Fimmers, Rolf [University of Bonn, Department of Medical Biometry, Informatics, and Epidemiology, Bonn (Germany)

    2015-11-15

    Our aim was to retrospectively evaluate the occurrence of respiratory motion artefacts in patients undergoing dynamic liver magnetic resonance (MR) either with gadoxetate disodium or gadobutrol. Two hundred and thirty liver MR studies (115 with gadobutrol, 115 with gadoxetate disodium) were analysed. Respiratory motion artefacts on dynamic 3D T1-weighted MR images (pre-contrast, arterial, venous, and late-dynamic phase) were assessed using a five-point rating scale. Severe motion was defined as a score ≥ 4. Mean motion scores were compared with the Mann-Whitney-U-test. The chi-squared-test was used for dichotomous comparisons. Mean motion scores for gadoxetate disodium and gadobutrol showed no relevant differences for each phase of the dynamic contrast series (pre-contrast: 1.85 ± 0.70 vs. 1.88 ± 0.57, arterial: 1.85 ± 0.81 vs. 1.87 ± 0.74, venous: 1.82 ± 0.67 vs. 1.74 ± 0.64, late-dynamic: 1.75 ± 0.62 vs. 1.79 ± 0.63; p = 0.469, 0.557, 0.382 and 0.843, respectively). Severe motion artefacts had a similar incidence using gadoxetate disodium and gadobutrol (11/460 [2.4 %] vs. 7/460 [1.5 %]; p = 0.341). Gadoxetate disodium is associated with equivalent motion scores compared to gadobutrol in dynamic liver MRI. In addition, both contrast agents demonstrated a comparable and acceptable rate of severe respiratory motion artefacts. (orig.)

  4. A continuous spectrophotometric assay for monitoring adenosine 5'-monophosphate production.

    Science.gov (United States)

    First, Eric A

    2015-08-15

    A number of biologically important enzymes release adenosine 5'-monophosphate (AMP) as a product, including aminoacyl-tRNA synthetases, cyclic AMP (cAMP) phosphodiesterases, ubiquitin and ubiquitin-like ligases, DNA ligases, coenzyme A (CoA) ligases, polyA deadenylases, and ribonucleases. In contrast to the abundance of assays available for monitoring the conversion of adenosine 5'-triphosphate (ATP) to ADP, there are relatively few assays for monitoring the conversion of ATP (or cAMP) to AMP. In this article, we describe a homogeneous assay that continuously monitors the production of AMP. Specifically, we have coupled the conversion of AMP to inosine 5'-monophosphate (IMP) (by AMP deaminase) to the oxidation of IMP (by IMP dehydrogenase). This results in the reduction of oxidized nicotine adenine dinucleotide (NAD(+)) to reduced nicotine adenine dinucleotide (NADH), allowing AMP formation to be monitored by the change in the absorbance at 340 nm. Changes in AMP concentrations of 5 μM or more can be reliably detected. The ease of use and relatively low expense make the AMP assay suitable for both high-throughput screening and kinetic analyses. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. ABC gene expression profiles have clinical importance and possibly form a new hallmark of cancer.

    Science.gov (United States)

    Dvorak, Pavel; Pesta, Martin; Soucek, Pavel

    2017-05-01

    Adenosine triphosphate-binding cassette proteins constitute a large family of active transporters through extracellular and intracellular membranes. Increased drug efflux based on adenosine triphosphate-binding cassette protein activity is related to the development of cancer cell chemoresistance. Several articles have focused on adenosine triphosphate-binding cassette gene expression profiles (signatures), based on the expression of all 49 human adenosine triphosphate-binding cassette genes, in individual tumor types and reported connections to established clinicopathological features. The aim of this study was to test our theory about the existence of adenosine triphosphate-binding cassette gene expression profiles common to multiple types of tumors, which may modify tumor progression and provide clinically relevant information. Such general adenosine triphosphate-binding cassette profiles could constitute a new attribute of carcinogenesis. Our combined cohort consisted of tissues from 151 cancer patients-breast, colorectal, and pancreatic carcinomas. Standard protocols for RNA isolation and quantitative real-time polymerase chain reaction were followed. Gene expression data from individual tumor types as well as a merged tumor dataset were analyzed by bioinformatics tools. Several general adenosine triphosphate-binding cassette profiles, with differences in gene functions, were established and shown to have significant relations to clinicopathological features such as tumor size, histological grade, or clinical stage. Genes ABCC7, A3, A8, A12, and C8 prevailed among the most upregulated or downregulated ones. In conclusion, the results supported our theory about general adenosine triphosphate-binding cassette gene expression profiles and their importance for cancer on clinical as well as research levels. The presence of ABCC7 (official symbol CFTR) among the genes with key roles in the profiles supports the emerging evidence about its crucial role in various

  6. Identification of the A2 adenosine receptor binding subunit by photoaffinity crosslinking

    International Nuclear Information System (INIS)

    Barrington, W.W.; Jacobson, K.A.; Hutchison, A.J.; Williams, M.; Stiles, G.L.

    1989-01-01

    A high-affinity iodinated agonist radioligand for the A2 adenosine receptor has been synthesized to facilitate studies of the A2 adenosine receptor binding subunit. The radioligand 125I-labeled PAPA-APEC (125I-labeled 2-[4-(2-[2-[(4- aminophenyl)methylcarbonylamino]ethylaminocarbonyl]- ethyl)phenyl]ethylamino-5'-N-ethylcarboxamidoadenosine) was synthesized and found to bind to the A2 adenosine receptor in bovine striatal membranes with high affinity (Kd = 1.5 nM) and A2 receptor selectivity. Competitive binding studies reveal the appropriate A2 receptor pharmacologic potency order with 5'-N-ethylcarboxamidoadenosine (NECA) greater than (-)-N6-[(R)-1-methyl- 2-phenylethyl]adenosine (R-PIA) greater than (+)-N6-[(S)-1-methyl-2- phenylethyl]adenosine (S-PIA). Adenylate cyclase assays, in human platelet membranes, demonstrate a dose-dependent stimulation of cAMP production. PAPA-APEC (1 microM) produces a 43% increase in cAMP production, which is essentially the same degree of increase produced by 5'-N- ethylcarboxamidoadenosine (the prototypic A2 receptor agonist). These findings combined with the observed guanine nucleotide-mediated decrease in binding suggest that PAPA-APEC is a full A2 agonist. The A2 receptor binding subunit was identified by photoaffinity-crosslinking studies using 125I-labeled PAPA-APEC and the heterobifunctional crosslinking agent N-succinimidyl 6-(4'-azido-2'-nitrophenylamino)hexanoate (SANPAH). After covalent incorporation, a single specifically radiolabeled protein with an apparent molecular mass of 45 kDa was observed on NaDodSO4/PAGE/autoradiography. Incorporation of 125I-labeled PAPA-APEC into this polypeptide is blocked by agonists and antagonists with the expected potency for A2 receptors and is decreased in the presence of 10(-4) M guanosine 5'-[beta, gamma-imido]triphosphate

  7. 40 CFR 180.1121 - Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Boric acid and its salts, borax... salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate, boric oxide (boric anhydride... its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate, boric oxide (boric...

  8. Transient severe respiratory motion artifacts after application of gadoxetate disodium. What we currently know

    International Nuclear Information System (INIS)

    Well, Lennart; Weinrich, Julius Matthias; Adam, Gerhard; Bannas, Peter

    2018-01-01

    Gadoxetate disodium is an intracellular contrast agent for magnetic resonance imaging (MRI) of the liver. Recent publications revealed that injection of gadoxetate disodium can lead to imaging artifacts due to transient severe motion (TSM) in the arterial phase of contrast-enhanced liver MRI. In this review we present and discuss published frequencies of TSM, contrast injection and image acquisition protocols, potential risk factors, and proposed strategies to avoid or minimize the effects of TSM. Two reviewers independently searched the PubMed search engine for ''transient severe motion artifact'' and related terms. Reference lists of retrieved articles were also searched. The two reviewers selected in consensus nine studies that reported both frequencies of TSM and potential risk factors. Study data were extracted by both reviewers, and disagreement was resolved by consensus. TSM is caused by impaired breath-hold ability after gadoxetate disodium injection and occurs in 5 -22% of patients. The dose of applied contrast agent, repeated exposure to gadoxetate disodium, high BMI and pulmonary disease have been described as potential risk factors for TSM. However, there are only few concordant results on this topic and the pathophysiology of TSM has not been identified. Proposed strategies for the prevention of TSM are slow injection rates and low doses of diluted gadoxetate disodium. Accelerated and free-breathing MRI sequence protocols and breath-hold training may minimize the effects of TSM. Further prospective studies are needed to confirm these strategies and to identify the underlying mechanism of TSM.

  9. Transient severe respiratory motion artifacts after application of gadoxetate disodium. What we currently know

    Energy Technology Data Exchange (ETDEWEB)

    Well, Lennart; Weinrich, Julius Matthias; Adam, Gerhard; Bannas, Peter [Univ. Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Diagnostic and Interventional Radiology and Nuclear Medicince

    2018-01-15

    Gadoxetate disodium is an intracellular contrast agent for magnetic resonance imaging (MRI) of the liver. Recent publications revealed that injection of gadoxetate disodium can lead to imaging artifacts due to transient severe motion (TSM) in the arterial phase of contrast-enhanced liver MRI. In this review we present and discuss published frequencies of TSM, contrast injection and image acquisition protocols, potential risk factors, and proposed strategies to avoid or minimize the effects of TSM. Two reviewers independently searched the PubMed search engine for ''transient severe motion artifact'' and related terms. Reference lists of retrieved articles were also searched. The two reviewers selected in consensus nine studies that reported both frequencies of TSM and potential risk factors. Study data were extracted by both reviewers, and disagreement was resolved by consensus. TSM is caused by impaired breath-hold ability after gadoxetate disodium injection and occurs in 5 -22% of patients. The dose of applied contrast agent, repeated exposure to gadoxetate disodium, high BMI and pulmonary disease have been described as potential risk factors for TSM. However, there are only few concordant results on this topic and the pathophysiology of TSM has not been identified. Proposed strategies for the prevention of TSM are slow injection rates and low doses of diluted gadoxetate disodium. Accelerated and free-breathing MRI sequence protocols and breath-hold training may minimize the effects of TSM. Further prospective studies are needed to confirm these strategies and to identify the underlying mechanism of TSM.

  10. New Polymorphic Forms of Pemetrexed Diacid and Their Use for the Preparation of Pharmaceutically Pure Amorphous and Hemipentahydrate Forms of Pemetrexed Disodium

    OpenAIRE

    Michalak, Olga; Łaszcz, Marta; Jatczak, Kamil; Witkowska, Anna; Bujak, Iwona; Groman, Aleksandra; Cybulski, Marcin

    2015-01-01

    The preparation of stable amorphous pemetrexed disodium of pharmaceutical purity as well as the process optimization for the preparation of the hemipentahydrate form of pemetrexed disodium are described. Analytical methods for the polymorphic and chemical purity studies of pemetrexed disodium and pemetrexed diacid forms were developed. The physicochemical properties of the amorphous and hydrate forms of pemetrexed disodium, as well as new forms of pemetrexed diacid (a key synthetic intermedia...

  11. New Polymorphic Forms of Pemetrexed Diacid and Their Use for the Preparation of Pharmaceutically Pure Amorphous and Hemipentahydrate Forms of Pemetrexed Disodium

    Directory of Open Access Journals (Sweden)

    Olga Michalak

    2015-07-01

    Full Text Available The preparation of stable amorphous pemetrexed disodium of pharmaceutical purity as well as the process optimization for the preparation of the hemipentahydrate form of pemetrexed disodium are described. Analytical methods for the polymorphic and chemical purity studies of pemetrexed disodium and pemetrexed diacid forms were developed. The physicochemical properties of the amorphous and hydrate forms of pemetrexed disodium, as well as new forms of pemetrexed diacid (a key synthetic intermediate were studied by thermal analysis and powder X-ray diffraction. High-performance liquid chromatography and gas chromatography methods were used for the chemical purity and residual solvents determination. In order to study the polymorphic and chemical stability of the amorphous and hemipentahydrate forms, a hygroscopicity test (25 °C, 80% RH was performed. Powder diffraction and high-performance liquid chromatography analyses revealed that the amorphous character and high chemical purity were preserved after the hygroscopicity test. The hemipentahydrate form transformed completely to the heptahydrate form of pemetrexed disodium. Both pemetrexed disodium forms were produced with high efficiency and pharmaceutical purity in a small commercial scale. Amorphous pemetrexed disodium was selected for further pharmaceutical development. Two new polymorphs (forms 1 and 2 of pemetrexed diacid were used for the preparation of high purity amorphous pemetrexed disodium.

  12. Biotin increases glucokinase expression via soluble guanylate cyclase/protein kinase G, adenosine triphosphate production and autocrine action of insulin in pancreatic rat islets.

    Science.gov (United States)

    Vilches-Flores, Alonso; Tovar, Armando R; Marin-Hernandez, Alvaro; Rojas-Ochoa, Alberto; Fernandez-Mejia, Cristina

    2010-07-01

    Besides its role as a carboxylase prosthetic group, biotin has important effects on gene expression. However, the molecular mechanisms through which biotin exerts these effects are largely unknown. We previously found that biotin increases pancreatic glucokinase expression. We have now explored the mechanisms underlying this effect. Pancreatic islets from Wistar rats were treated with biotin, in the presence or absence of different types of inhibitors. Glucokinase mRNA and 18s rRNA abundance were determined by real-time PCR. Adenosine triphosphate (ATP) content was analyzed by fluorometry. Biotin treatment increased glucokinase mRNA abundance approximately one fold after 2 h; the effect was sustained up to 24 h. Inhibition of soluble guanylate cyclase or protein kinase G (PKG) signalling suppressed biotin-induced glucokinase expression. The cascade of events downstream of PKG in biotin-mediated gene transcription is not known. We found that inhibition of insulin secretion with diazoxide or nifedipine prevented biotin-stimulated glucokinase mRNA increase. Biotin treatment increased islet ATP content (control: 4.68+/-0.28; biotin treated: 6.62+/-0.26 pmol/islet) at 30 min. Inhibition of PKG activity suppressed the effects of biotin on ATP content. Insulin antibodies or inhibitors of phosphoinositol-3-kinase/Akt insulin signalling pathway prevented biotin-induced glucokinase expression. The nucleotide 8-Br-cGMP mimicked the biotin effects. We propose that the induction of pancreatic glucokinase mRNA by biotin involves guanylate cyclase and PKG activation, which leads to an increase in ATP content. This induces insulin secretion via ATP-sensitive potassium channels. Autocrine insulin, in turn, activates phosphoinositol-3-kinase/Akt signalling. Our results offer new insights into the pathways that participate in biotin-mediated gene expression. (c) 2010 Elsevier Inc. All rights reserved.

  13. Adenosine 5′-Triphosphate Metabolism in Red Blood Cells as a Potential Biomarker for Post-Exercise Hypotension and a Drug Target for Cardiovascular Protection

    Directory of Open Access Journals (Sweden)

    Pollen K. Yeung

    2018-05-01

    Full Text Available The importance of adenosine and ATP in regulating many biological functions has long been recognized, especially for their effects on the cardiovascular system, which may be used for management of hypertension and cardiometabolic diseases. In response to ischemia and cardiovascular injury, ATP is broken down to release adenosine. The effect of adenosine is very short lived because it is rapidly taken up by erythrocytes (RBCs, myocardial and endothelial cells, and also rapidly catabolized to oxypurine metabolites. Intracellular adenosine is phosphorylated back to adenine nucleotides via a salvage pathway. Extracellular and intracellular ATP is broken down rapidly to ADP and AMP, and finally to adenosine by 5′-nucleotidase. These metabolic events are known to occur in the myocardium, endothelium as well as in RBCs. Exercise has been shown to increase metabolism of ATP in RBCs, which may be an important mechanism for post-exercise hypotension and cardiovascular protection. The post-exercise effect was greater in hypertensive than in normotensive rats. The review summarizes current evidence in support of ATP metabolism in the RBC as a potential surrogate biomarker for cardiovascular protection and toxicities. It also discusses the opportunities, challenges, and obstacles of exploiting ATP metabolism in RBCs as a target for drug development and precision medicine.

  14. Comparative in vitro studies on disodium EDTA effect with and without Proteus mirabilis on the crystallization of carbonate apatite and struvite

    Science.gov (United States)

    Prywer, Jolanta; Olszynski, Marcin; Torzewska, Agnieszka; Mielniczek-Brzóska, Ewa

    2014-06-01

    Effect of disodium EDTA (salt of ethylenediamine tetraacetic acid) on the crystallization of struvite and carbonate apatite was studied. To evaluate such an effect we performed an experiment of struvite and carbonate apatite growth from artificial urine. The crystallization process was induced by Proteus mirabilis to mimic the real urinary tract infection, which usually leads to urinary stone formation. The results demonstrate that disodium EDTA exhibits the effect against P. mirabilis retarding the activity of urease - an enzyme produced by these microorganisms. The spectrophotometric results demonstrate that, with and without P. mirabilis, the addition of disodium EDTA increases the induction time and decreases the growth efficiency compared to the baseline (without disodium EDTA). These results are discussed from the standpoint of speciation of complexes formed in the solution of artificial urine in the presence of disodium EDTA. The size of struvite crystals was found to decrease in the presence of disodium EDTA. However, struvite crystals are larger in the presence of bacteria while the crystal morphology and habit remain unchanged.

  15. 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...

  16. Comparative enzymology of the adenosine triphosphate sulfurylases from leaf tissue of selenium-accumulator and non-accumulator plants

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, W H; Anderson, J W

    1974-01-01

    ATP sulfurylases were partially purified (20-40-fold) from leaf tissue of Astragalus bisulcatus, Astragalus racemosus (selenium-accumulator species) and Astragalus hamosus and Astragalus sinicus (non-accumulator species). Activity was measured by sulfate-dependent PP/sub 1/-ATP exchange. The enzymes were separated from pyrophosphatase and adenosine triphosphatase activities. The properties of the Astragalus ATP sulfurylases were similar to the spinach enzyme. The ATP sulfurylases from both selenium-accumulator and non-accumulator species catalyzed selenate-dependent PP/sub 1/-ATP exchange; selenate competed with sulfate. The ratio of V(selenate)/V(sulfate) and K/sub m/ (selenate)/K/sub m/(sulfate) was approximately the same for the enzyme from each species. Sulfate-dependent PP/sub 1/-ATP exchange was inhibited by ADP, chlorate and nitrate. The kinetics of the inhibition for each enzyme were consistent with an ordered reaction mechanisms, in which ATP is the first substrate to react with the enzyme and PP/sub 1/ is the first product released. Synthesis of adenosine 5'-(/sup 35/S)sulfatophosphate from (/sup 35/S)sulfate was demonstrated by coupling the Astrgalus ATP sulfurylases with Mg/sup 2 +/-dependent pyrophosphatase; the reaction was inhibited by selenate. An analogous reaction using (/sup 75/Se)selenate as substrate could not be demonstrated.

  17. Adenosine and preeclampsia.

    Science.gov (United States)

    Salsoso, Rocío; Farías, Marcelo; Gutiérrez, Jaime; Pardo, Fabián; Chiarello, Delia I; Toledo, Fernando; Leiva, Andrea; Mate, Alfonso; Vázquez, Carmen M; Sobrevia, Luis

    2017-06-01

    Adenosine is an endogenous nucleoside with pleiotropic effects in different physiological processes including circulation, renal blood flow, immune function, or glucose homeostasis. Changes in adenosine membrane transporters, adenosine receptors, and corresponding intracellular signalling network associate with development of pathologies of pregnancy, including preeclampsia. Preeclampsia is a cause of maternal and perinatal morbidity and mortality affecting 3-5% of pregnancies. Since the proposed mechanisms of preeclampsia development include adenosine-dependent biological effects, adenosine membrane transporters and receptors, and the associated signalling mechanisms might play a role in the pathophysiology of preeclampsia. Preeclampsia associates with increased adenosine concentration in the maternal blood and placental tissue, likely due to local hypoxia and ischemia (although not directly demonstrated), microthrombosis, increased catecholamine release, and platelet activation. In addition, abnormal expression and function of equilibrative nucleoside transporters is described in foetoplacental tissues from preeclampsia; however, the role of adenosine receptors in the aetiology of this disease is not well understood. Adenosine receptors activation may be related to abnormal trophoblast invasion, angiogenesis, and ischemia/reperfusion mechanisms in the placenta from preeclampsia. These mechanisms may explain only a low fraction of the associated abnormal transformation of spiral arteries in preeclampsia, triggering cellular stress and inflammatory mediators release from the placenta to the maternal circulation. Although increased adenosine concentration in preeclampsia may be a compensatory or adaptive mechanism favouring placental angiogenesis, a poor angiogenic state is found in preeclampsia. Thus, preeclampsia-associated complications might affect the cell response to adenosine due to altered expression and activity of adenosine receptors, membrane transporters

  18. Actinides and rare earths complexation with adenosine phosphate nucleotides

    International Nuclear Information System (INIS)

    Mostapha, Sarah

    2013-01-01

    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

  19. Molecular studies on di-sodium tartrate molecule

    Science.gov (United States)

    Divya, P.; Jayakumar, S.; George, Preethamary; Shubashree, N. S.; Ahmed. M, Anees

    2015-06-01

    Structural characterization is important for the development of new material. The acoustical parameters such as Free Length, Internal Pressure have been measured from ultrasonic velocity, density for di sodium tartrate an optically active molecule at different temperatures using ultrasonic interferometer of frequency (2MHZ). The ultrasonic velocity increases with increase in concentration there is an increase in solute-solvent interaction. The stability constant had been calculated. SEM with EDAX studies has been done for Di-sodium tartrate an optically active molecule.

  20. Microwave-Assisted Hydrothermal Synthesis of Cellulose/Hydroxyapatite Nanocomposites

    Directory of Open Access Journals (Sweden)

    Lian-Hua Fu

    2016-09-01

    Full Text Available In this paper, we report a facile, rapid, and green strategy for the synthesis of cellulose/hydroxyapatite (HA nanocomposites using an inorganic phosphorus source (sodium dihydrogen phosphate dihydrate (NaH2PO4·2H2O, or organic phosphorus sources (adenosine 5′-triphosphate disodium salt (ATP, creatine phosphate disodium salt tetrahydrate (CP, or D-fructose 1,6-bisphosphate trisodium salt octahydrate (FBP through the microwave-assisted hydrothermal method. The effects of the phosphorus sources, heating time, and heating temperature on the phase, size, and morphology of the products were systematically investigated. The experimental results revealed that the phosphate sources played a critical role on the phase, size, and morphology of the minerals in the nanocomposites. For example, the pure HA was obtained by using NaH2PO4·2H2O as phosphorus source, while all the ATP, CP, and FBP led to the byproduct, calcite. The HA nanostructures with various morphologies (including nanorods, pseudo-cubic, pseudo-spherical, and nano-spherical particles were obtained by varying the phosphorus sources or adjusting the reaction parameters. In addition, this strategy is surfactant-free, avoiding the post-treatment procedure and cost for the surfactant removal from the product. We believe that this work can be a guidance for the green synthesis of cellulose/HA nanocomposites in the future.

  1. Stimulation of Escherichia coli DNA photoreactivating enzyme activity by adenosine 5'-triphosphate

    International Nuclear Information System (INIS)

    Koka, P.

    1984-01-01

    A purification procedure consisting of Biorex-70, single-stranded DNA-agarose, and ultraviolet (UV) light irradiated DNA-cellulose chromatography has been adopted for the Escherichia coli photoreactivating enzyme, to obtain enzyme preparations that are free of extraneous nucleic acid or nucleotides. The purification yields high specific activities (75 000 pmol h -1 mg -1 ) with a 50% recovery. Enzyme preparations have also been obtained from UV-irradiated DNA-cellulose by exposure to visible light. These enzyme preparations contain oligoribonucleotides, up to 26 nucleotides in length in relation to DNA size markers, but these are not essential for enzymatic activity. When the enzyme is preincubated with exogenous ATP a 10-fold stimulation in the enzyme activity has been observed. It has been determined by polyacrylamide gel electrophoresis and high-voltage diethylaminoethyl paper electrophoresis that the light-released enzyme samples from a preincubated and washed mixture of the enzyme, [γ- 32 P]ATP, and UV-irradiated DNA-cellulose contained exogenous [γ- 32 P], which eluted with the enzyme-containing fractions when subjected to Bio-Gel P-30 chromatography. GTP caused a slight enhancement of the enzyme activity while ADP strongly inhibited photoreactivation, at the same concentration and conditions. Higher (X5) concentrations of ADP and adenosine 5'-(β, γ-methylenetriphosphate) totally inhibited the enzyme activity. Dialysis of a photoreactivating enzyme preparation against a buffer solution containing 1 mM ATP caused a 9-fold stimulation of the enzyme activity. In addition, there is an apparent hydrolysis of ATP during photoreactivation as measured by the release of 32 P from [γ- 32 P]ATP

  2. Kinetic mechanism of Toxoplasma gondii adenosine kinase and the highly efficient utilization of adenosine

    Science.gov (United States)

    Naguib, Fardos N. M.; Rais, Reem H.; Al Safarjalani, Omar N.; el Kouni, Mahmoud H.

    2015-01-01

    Toxoplasma gondii has an extraordinarily ability to utilize adenosine (Ado) as the primary source of all necessary purines in this parasite which lacks de novo purine biosynthesis. The activity of T. gondii adenosine kinase (TgAK, EC 2.7.1.20) is responsible for this efficient salvage of Ado in T. gondii. To fully understand this remarkable efficiency of TgAK in the utilization of Ado, complete kinetic parameters of this enzyme are necessary. Initial velocity and product inhibition studies of TgAK demonstrated that the basic mechanism of this enzyme is a hybrid random bi-uni ping-pong uni-bi. Initial velocity studies showed an intersecting pattern, consistent with substrate-enzyme-co-substrate complex formation and a binding pattern indicating that binding of the substrate interferes with the binding of the co-substrate and vice versa. Estimated kinetic parameters were KAdo = 0.002 ± 0.0002 mM, KATP = 0.05 ± 0.008 mM, and Vmax = 920 ± 35 μmol/min/mg protein. Ado exhibited substrate inhibition suggesting the presence of more than one binding site for Ado on the enzyme. ATP relieved substrate inhibition by Ado. Thus, Ado also binds to the ATP binding site. AMP was competitive with ATP, inferring that AMP binds to the same site as ATP. AMP, ADP and ATP were non-competitive with Ado, therefore, none of these nucleotides binds to the Ado binding site. Combining ATP with ADP was additive. Therefore, the binding of either ATP or ADP does not interfere with the binding of the other. It is concluded that for every ATP consumed, TgAK generates three new AMPs. These findings along with the fact that a wide range of nucleoside 5′-mono, di, and triphosphates could substitute for ATP as phosphate donors in this reaction may explain the efficient and central role played by TgAK in the utilization of Ado as the major source from which all other purines can be synthesized in T. gondii. PMID:26112826

  3. Crystal structure studies on plate/shelf like disodium ditungstate

    Indian Academy of Sciences (India)

    Inorganic materials; disodium ditungstate; crystal structure; scanning electron microscopy; X-ray ... generation, and horizontal electric furnace with quartz tube ... Unit cell dimensions: a = 7·22192(11) Е, b = 11·91559(17) Е, c = 14·74755(23) Е. Cell content: 8 Na2W2O7). Atom. Position. X(σ(X)). Y(σ(Y)). Z(σ(Z)). B(σ(B)). W (1).

  4. Partial separation of platelet and placental adenosine receptors from adenosine A2-like binding protein

    International Nuclear Information System (INIS)

    Zolnierowicz, S.; Work, C.; Hutchison, K.; Fox, I.H.

    1990-01-01

    The ubiquitous adenosine A2-like binding protein obscures the binding properties of adenosine receptors assayed with 5'-N-[ 3 H]ethylcarboxamidoadenosine [( 3 H]NECA). To solve this problem, we developed a rapid and simple method to separate adenosine receptors from the adenosine A2-like binding protein. Human platelet and placental membranes were solubilized with 1% 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate. The soluble platelet extract was precipitated with polyethylene glycol and the fraction enriched in adenosine receptors was isolated from the precipitate by differential centrifugation. The adenosine A2-like binding protein was removed from the soluble placental extract with hydroxylapatite and adenosine receptors were precipitated with polyethylene glycol. The specificity of the [ 3 H]NECA binding is typical of an adenosine A2 receptor for platelets and an adenosine A1 receptor for placenta. This method leads to enrichment of adenosine A2 receptors for platelets and adenosine A1 receptors for placenta. This provides a useful preparation technique for pharmacologic studies of adenosine receptors

  5. Edetate Disodium-Based Treatment for Secondary Prevention in Post-Myocardial Infarction Patients.

    Science.gov (United States)

    Lamas, Gervasio A; Issa, Omar M

    2016-02-01

    An abundance of data, known for decades, is available linking metals, such as lead and cadmium, with cardiovascular disease. However, the idea that these toxic metals could be a modifiable risk factor for atherosclerosis did not become apparent clinically until the completion of the Trial to Assess Chelation Therapy in 2012. This pivotal study was the first double-blind, randomized, controlled trial of its kind to demonstrate a clear improvement in cardiovascular outcomes with edetate disodium therapy in a secondary prevention, post-myocardial infarction population. This effect size was most striking in diabetic patients, where the efficacy of edetate disodium was comparable, if not superior, to that of current guideline-based therapies. Given the economic burden of diabetes and cardiovascular disease, the potential impact of this therapy could be enormous if the results of this study are replicated.

  6. Research on garlic capsule and selenium-vitamin A, vitamin B, vitamin C applied in therapy of acute hepatocellular damage in a rat model

    Directory of Open Access Journals (Sweden)

    Jacob Kehinde Akintunde

    2015-10-01

    Conclusions: Collectively, the results suggest that therapeutic dose of lisinopril elicits toxicity in male rats through induction of oxidative damage and depletion of cellular adenosine triphosphate. The reversal effects of GAR and SACE during lisinopril treatment suggest that these antioxidants may find clinical application in cellular damage involving ROS and adenosine triphosphate.

  7. Assessment of arterial hypervascularity of hepatocellular carcinoma: comparison of contrast-enhanced US and gadoxetate disodium-enhanced MR imaging

    International Nuclear Information System (INIS)

    Sugimoto, Katsutoshi; Moriyasu, Fuminori; Taira, Junichi; Imai, Yasuharu; Shiraishi, Junji; Saito, Kazuhiro; Saguchi, Toru

    2012-01-01

    To compare contrast-enhanced (CE) ultrasound with gadoxetate disodium-enhanced magnetic resonance (MR) imaging in the assessment of arterial hypervascularity of hepatocellular carcinoma (HCC) and dysplastic nodule (DN), with CT during hepatic arteriography (CTHA) as the reference standard. This study included 54 consecutively diagnosed patients, with 57 histologically confirmed HCCs and 3 DNs (high-grade). All patients underwent CE ultrasound, gadoxetate disodium-enhanced MR imaging and CTHA. Two trained diagnostic radiologists interpreted the CTHA images and rated the degree of intratumoral arterial vascularity by consensus using a five-point confidence scale as the reference standard. In the observer study, the degrees of vascularity on CE ultrasound and gadoxetate disodium-enhanced MR images were qualitatively analysed by four independent readers using a five-point confidence scale. Diagnostic accuracy was analysed by receiver-operating characteristic (ROC) analysis. The diagnostic accuracies of the average area under the ROC curve (AUC) were significantly greater with CE ultrasound (average AUC: 0.94; 95% confidence interval [CI]: 0.88-1.00) than with gadoxetate disodium-enhanced MR imaging (average AUC 0.84, 95% CI 0.74-0.93, P = 0.0014). Contrast-enhanced ultrasound yields a significantly higher AUC value than gadoxetate disodium-enhanced MR imaging in the assessment of arterial hypervascularity of HCC and DN. Key Points circle Arterial hypervascularity is an important feature determining treatment options in hepatocellular carcinoma. circle It can be assessed by contrast-enhanced (CE) ultrasound or magnetic resonance (MR) imaging. circle CE ultrasound was more accurate than Gd-EOB-DTPA MRI in assessing intratumoral vascularity. circle Hypovascular hepatic nodules should be further investigated using CE ultrasound. (orig.)

  8. Radiorestoring activity of few nucleotides on normal tissues of Jerusalem Artichoke after an irradiation with γ rays of 60Co

    International Nuclear Information System (INIS)

    Jonard, Robert; Bayonove, Jacqueline; Riedel, Michel.

    1978-01-01

    The nucleotides tested: adenosine triphosphate (ATP) and cyclic adenosine 3',5'-monophosphate (3',5'-cAMP), guanosine triphosphate (GTP) and cyclic guanosine 3',5'-monophosphate (3',5'-cGMP), are able to restore proliferation to irradiated (γ irradiation, 3,000 rad) Jesusalem Artichoke tissue. The 3',5'-cGMP shows the greater radiorestoring activity [fr

  9. Hypervascular hepatocellular carcinomas: detection with gadoxetate disodium-enhanced MR imaging and multiphasic multidetector CT

    Energy Technology Data Exchange (ETDEWEB)

    Onishi, Hiromitsu; Kim, Tonsok; Hori, Masatoshi; Nakaya, Yasuhiro; Tsuboyama, Takahiro; Nakamoto, Atsushi; Tatsumi, Mitsuaki; Tomiyama, Noriyuki [Osaka University Graduate School of Medicine, Department of Radiology, Suita, Osaka (Japan); Imai, Yasuharu [Ikeda Municipal Hospital, Department of Gastroenterology, Ikeda, Osaka (Japan); Nagano, Hiroaki [Osaka University Graduate School of Medicine, Department of Surgery, Suita, Osaka (Japan); Kumano, Seishi; Okada, Masahiro; Murakami, Takamichi [Kinki University School of Medicine, Department of Radiology, Osakasayama, Osaka (Japan); Takamura, Manabu [Ikeda Municipal Hospital, Department of Radiology, Ikeda, Osaka (Japan); Wakasa, Kenichi [Osaka City University Graduate School of Medicine, Department of Diagnostic Pathology, Osaka, Osaka (Japan)

    2012-04-15

    To retrospectively compare the accuracy of detection of hypervascular hepatocellular carcinoma (HCC) by multiphasic multidetector CT and by gadoxetate disodium-enhanced MR imaging. After ethical approval, we analysed a total of 73 hypervascular HCC lesions from 31 patients suspected of having HCC, who underwent both gadoxetate disodium-enhanced MR imaging and multiphasic multidetector CT. Five blinded observers independently reviewed CT images, as well as dynamic MR images alone and combined with hepatobiliary phase MR images. Diagnostic accuracy (Az values), sensitivities and positive predictive values were compared by using the Scheffe post hoc test. The mean Az value for dynamic and hepatobiliary phase MR combined (0.81) or dynamic MR images alone (0.78) was significantly higher than that for CT images (0.67, P < 0.001, 0.005, respectively). The mean sensitivity of the combined MR images (0.67) was significantly higher than that of dynamic MR alone (0.52, P < 0.05) or CT images (0.44, P < 0.05). The mean positive predictive values were 0.96, 0.95 and 0.94, for CT, dynamic MR alone and combined MR images, respectively. Compared with multiphasic multidetector CT, gadoxetate disodium-enhanced MR imaging combining dynamic and hepatobiliary phase images results in significantly improved sensitivity and diagnostic accuracy for detection of hypervascular HCC. (orig.)

  10. Involvement of A1 adenosine receptors and neural pathways in adenosine-induced bronchoconstriction in mice.

    Science.gov (United States)

    Hua, Xiaoyang; Erikson, Christopher J; Chason, Kelly D; Rosebrock, Craig N; Deshpande, Deepak A; Penn, Raymond B; Tilley, Stephen L

    2007-07-01

    High levels of adenosine can be measured from the lungs of asthmatics, and it is well recognized that aerosolized 5'AMP, the precursor of adenosine, elicits robust bronchoconstriction in patients with this disease. Characterization of mice with elevated adenosine levels secondary to the loss of adenosine deaminase (ADA) expression, the primary metabolic enzyme for adenosine, further support a role for this ubiquitous mediator in the pathogenesis of asthma. To begin to identify pathways by which adenosine can alter airway tone, we examined adenosine-induced bronchoconstriction in four mouse lines, each lacking one of the receptors for this nucleoside. We show, using direct measures of airway mechanics, that adenosine can increase airway resistance and that this increase in resistance is mediated by binding the A(1) receptor. Further examination of this response using pharmacologically, surgically, and genetically manipulated mice supports a model in which adenosine-induced bronchoconstriction occurs indirectly through the activation of sensory neurons.

  11. Mitochondrial deoxyribonucleoside triphosphate pools in thymidine kinase 2 deficiency.

    Science.gov (United States)

    Saada, Ann; Ben-Shalom, Efrat; Zyslin, Rivka; Miller, Chaya; Mandel, Hanna; Elpeleg, Orly

    2003-10-24

    Deficiency of mitochondrial thymidine kinase (TK2) is associated with mitochondrial DNA (mtDNA) depletion and manifests by severe skeletal myopathy in infancy. In order to elucidate the pathophysiology of this condition, mitochondrial deoxyribonucleoside triphosphate (dNTP) pools were determined in patients' fibroblasts. Despite normal mtDNA content and cytochrome c oxidase (COX) activity, mitochondrial dNTP pools were imbalanced. Specifically, deoxythymidine triphosphate (dTTP) content was markedly decreased, resulting in reduced dTTP:deoxycytidine triphosphate ratio. These findings underline the importance of balanced mitochondrial dNTP pools for mtDNA synthesis and may serve as the basis for future therapeutic interventions.

  12. Transient Severe Motion Artifact Related to Gadoxetate Disodium-Enhanced Liver MRI: Frequency and Risk Evaluation at a German Institution.

    Science.gov (United States)

    Well, Lennart; Rausch, Vanessa Hanna; Adam, Gerhard; Henes, Frank Oliver; Bannas, Peter

    2017-07-01

    Purpose  Varying frequencies (5 - 18 %) of contrast-related transient severe motion (TSM) imaging artifacts during gadoxetate disodium-enhanced arterial phase liver MRI have been reported. Since previous reports originated from the United States and Japan, we aimed to determine the frequency of TSM at a German institution and to correlate it with potential risk factors and previously published results. Materials and Methods  Two age- and sex-matched groups were retrospectively selected (gadoxetate disodium n = 89; gadobenate dimeglumine n = 89) from dynamic contrast-enhanced MRI examinations in a single center. Respiratory motion-related artifacts in non-enhanced and dynamic phases were assessed independently by two readers blinded to contrast agents on a 4-point scale. Scores of ≥ 3 were considered as severe motion artifacts. Severe motion artifacts in arterial phases were considered as TSM if scores in all other phases were risk factors for TSM were evaluated via logistic regression analysis. Results  For gadoxetate disodium, the mean score for respiratory motion artifacts was significantly higher in the arterial phase (2.2 ± 0.9) compared to all other phases (1.6 ± 0.7) (p risk factors (all p > 0.05). Conclusion  We revealed a high frequency of TSM after injection of gadoxetate disodium at a German institution, substantiating the importance of a diagnosis-limiting phenomenon that so far has only been reported from the United States and Japan. In accordance with previous studies, we did not identify associated risk factors for TSM. Key Points:   · Gadoxetate disodium causes TSM in a relevant number of patients.. · The frequency of TSM is similar between the USA, Japan and Germany.. · To date, no validated risk factors for TSM could be identified.. Citation Format · Well L, Rausch VH, Adam G et al. Transient Severe Motion Artifact Related to Gadoxetate Disodium-Enhanced Liver MRI: Frequency and Risk Evaluation at a

  13. Adenosine receptor desensitization and trafficking.

    Science.gov (United States)

    Mundell, Stuart; Kelly, Eamonn

    2011-05-01

    As with the majority of G-protein-coupled receptors, all four of the adenosine receptor subtypes are known to undergo agonist-induced regulation in the form of desensitization and trafficking. These processes can limit the ability of adenosine receptors to couple to intracellular signalling pathways and thus reduce the ability of adenosine receptor agonists as well as endogenous adenosine to produce cellular responses. In addition, since adenosine receptors couple to multiple signalling pathways, these pathways may desensitize differentially, while the desensitization of one pathway could even trigger signalling via another. Thus, the overall picture of adenosine receptor regulation can be complex. For all adenosine receptor subtypes, there is evidence to implicate arrestins in agonist-induced desensitization and trafficking, but there is also evidence for other possible forms of regulation, including second messenger-dependent kinase regulation, heterologous effects involving G proteins, and the involvement of non-clathrin trafficking pathways such as caveolae. In this review, the evidence implicating these mechanisms is summarized for each adenosine receptor subtype, and we also discuss those issues of adenosine receptor regulation that remain to be resolved as well as likely directions for future research in this field. Copyright © 2010 Elsevier B.V. All rights reserved.

  14. Transient severe motion artifact related to gadoxetate disodium-enhanced liver MRI. Frequency and risk evaluation at a German institution

    Energy Technology Data Exchange (ETDEWEB)

    Well, Lennart; Rausch, Vanessa Hanna; Adam, Gerhard; Henes, Frank Oliver; Bannas, Peter [Univ. Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. for Diagnostic and Interventional Radiology and Nuclear Medicine

    2017-07-15

    Varying frequencies (5 - 18%) of contrast-related transient severe motion (TSM) imaging artifacts during gadoxetate disodium-enhanced arterial phase liver MRI have been reported. Since previous reports originated from the United States and Japan, we aimed to determine the frequency of TSM at a German institution and to correlate it with potential risk factors and previously published results. Two age- and sex-matched groups were retrospectively selected (gadoxetate disodium n = 89; gadobenate dimeglumine n = 89) from dynamic contrast-enhanced MRI examinations in a single center. Respiratory motion-related artifacts in non-enhanced and dynamic phases were assessed independently by two readers blinded to contrast agents on a 4-point scale. Scores of ≥3 were considered as severe motion artifacts. Severe motion artifacts in arterial phases were considered as TSM if scores in all other phases were < 3. Potential risk factors for TSM were evaluated via logistic regression analysis. For gadoxetate disodium, the mean score for respiratory motion artifacts was significantly higher in the arterial phase (2.2 ± 0.9) compared to all other phases (1.6 ± 0.7) (p < 0.05). The frequency of TSM was significantly higher with gadoxetate disodium (n = 19; 21.1 %) than with gadobenate dimeglumine (n = 1; 1.1%) (p < 0.001). The frequency of TSM at our institution is similar to some, but not all previously published findings. Logistic regression analysis did not show any significant correlation between TSM and risk factors (all p>0.05). We revealed a high frequency of TSM after injection of gadoxetate disodium at a German institution, substantiating the importance of a diagnosis-limiting phenomenon that so far has only been reported from the United States and Japan. In accordance with previous studies, we did not identify associated risk factors for TSM.

  15. AMP and adenosine are both ligands for adenosine 2B receptor signaling.

    Science.gov (United States)

    Holien, Jessica K; Seibt, Benjamin; Roberts, Veena; Salvaris, Evelyn; Parker, Michael W; Cowan, Peter J; Dwyer, Karen M

    2018-01-15

    Adenosine is considered the canonical ligand for the adenosine 2B receptor (A 2B R). A 2B R is upregulated following kidney ischemia augmenting post ischemic blood flow and limiting tubular injury. In this context the beneficial effect of A 2B R signaling has been attributed to an increase in the pericellular concentration of adenosine. However, following renal ischemia both kidney adenosine monophosphate (AMP) and adenosine levels are substantially increased. Using computational modeling and calcium mobilization assays, we investigated whether AMP could also be a ligand for A 2B R. The computational modeling suggested that AMP interacts with more favorable energy to A 2B R compared with adenosine. Furthermore, AMPαS, a non-hydrolyzable form of AMP, increased calcium uptake by Chinese hamster ovary (CHO) cells expressing the human A 2B R, indicating preferential signaling via the G q pathway. Therefore, a putative AMP-A 2B R interaction is supported by the computational modeling data and the biological results suggest this interaction involves preferential G q activation. These data provide further insights into the role of purinergic signaling in the pathophysiology of renal IRI. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. 40 CFR 721.3820 - L-Glutamic acid, N-(1-oxododecyl)-, disodium salt.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false L-Glutamic acid, N-(1-oxododecyl... Specific Chemical Substances § 721.3820 L-Glutamic acid, N-(1-oxododecyl)-, disodium salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as L-Glutamic...

  17. 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.; Regan, John M.

    2015-01-01

    © 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.

  18. 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.

  19. Piracetam prevents scopolamine-induced memory impairment and decrease of NTPDase, 5'-nucleotidase and adenosine deaminase activities.

    Science.gov (United States)

    Marisco, Patricia C; Carvalho, Fabiano B; Rosa, Michelle M; Girardi, Bruna A; Gutierres, Jessié M; Jaques, Jeandre A S; Salla, Ana P S; Pimentel, Víctor C; Schetinger, Maria Rosa C; Leal, Daniela B R; Mello, Carlos F; Rubin, Maribel A

    2013-08-01

    Piracetam improves cognitive function in animals and in human beings, but its mechanism of action is still not completely known. In the present study, we investigated whether enzymes involved in extracellular adenine nucleotide metabolism, adenosine triphosphate diphosphohydrolase (NTPDase), 5'-nucleotidase and adenosine deaminase (ADA) are affected by piracetam in the hippocampus and cerebral cortex of animals subjected to scopolamine-induced memory impairment. Piracetam (0.02 μmol/5 μL, intracerebroventricular, 60 min pre-training) prevented memory impairment induced by scopolamine (1 mg/kg, intraperitoneal, immediately post-training) in the inhibitory avoidance learning and in the object recognition task. Scopolamine reduced the activity of NTPDase in hippocampus (53 % for ATP and 53 % for ADP hydrolysis) and cerebral cortex (28 % for ATP hydrolysis). Scopolamine also decreased the activity of 5'-nucleotidase (43 %) and ADA (91 %) in hippocampus. The same effect was observed in the cerebral cortex for 5'-nucleotidase (38 %) and ADA (68 %) activities. Piracetam fully prevented scopolamine-induced memory impairment and decrease of NTPDase, 5'-nucleotidase and adenosine deaminase activities in synaptosomes from cerebral cortex and hippocampus. In vitro experiments show that piracetam and scopolamine did not alter enzymatic activity in cerebral cortex synaptosomes. Moreover, piracetam prevented scopolamine-induced increase of TBARS levels in hippocampus and cerebral cortex. These results suggest that piracetam-induced improvement of memory is associated with protection against oxidative stress and maintenance of NTPDase, 5'-nucleotidase and ADA activities, and suggest the purinergic system as a putative target of piracetam.

  20. Purinergic signaling pathways in endocrine system.

    Science.gov (United States)

    Bjelobaba, Ivana; Janjic, Marija M; Stojilkovic, Stanko S

    2015-09-01

    Adenosine-5'-triphosphate is released by neuroendocrine, endocrine, and other cell types and acts as an extracellular agonist for ligand-gated P2X cationic channels and G protein-coupled P2Y receptors in numerous organs and tissues, including the endocrine system. The breakdown of ATP by ectonucleotidases not only terminates its extracellular messenger functions, but also provides a pathway for the generation of two additional agonists: adenosine 5'-diphosphate, acting via some P2Y receptors, and adenosine, a native agonist for G protein-coupled adenosine receptors, also expressed in the endocrine system. This article provides a review of purinergic signaling pathways in the hypothalamic magnocellular neurosecretory cells and neurohypophysis, hypothalamic parvocellular neuroendocrine system, adenohypophysis, and effector glands organized in five axes: hypothalamic-pituitary-gonadal, hypothalamic-pituitary-thyroid, hypothalamic-pituitary-adrenal, hypothalamic-pituitary-growth hormone, and hypothalamic-pituitary-prolactin. We attempted to summarize current knowledge of purinergic receptor subtypes expressed in the endocrine system, including their roles in intracellular signaling, hormone secretion, and other cell functions. We also briefly review the release mechanism for adenosine-5'-triphosphate by neuroendocrine, endocrine and surrounding cells, the enzymes involved in adenosine-5'-triphosphate hydrolysis to adenosine-5'-diphosphate and adenosine, and the relevance of this pathway for sequential activation of receptors and termination of signaling. Published by Elsevier B.V.

  1. Purinergic Signaling Pathways in Endocrine System

    Science.gov (United States)

    Bjelobaba, Ivana; Janjic, Marija M.; Stojilkovic, Stanko S.

    2015-01-01

    Adenosine-5′-triphosphate is released by neuroendocrine, endocrine, and other cell types and acts as an extracellular agonist for ligand-gated P2X cationic channels and G protein-coupled P2Y receptors in numerous organs and tissues, including the endocrine system. The breakdown of ATP by ectonucleotidases not only terminates its extracellular messenger functions, but also provides a pathway for the generation of two additional agonists: adenosine 5′-diphosphate, acting via some P2Y receptors, and adenosine, a native agonist for G protein-coupled adenosine receptors, also expressed in the endocrine system. This article provides a review of purinergic signaling pathways in the hypothalamic magnocellular neurosecretory cells and neurohypophysis, hypothalamic parvocellular neuroendocrine system, adenohypophysis, and effector glands organized in five axes: hypothalamic-pituitary-gonadal, hypothalamic-pituitary-thyroid, hypothalamic-pituitary-adrenal, hypothalamic-pituitary-growth hormone, and hypothalamic-pituitary-prolactin. We attempted to summarize current knowledge of purinergic receptor subtypes expressed in the endocrine system, including their roles in intracellular signaling, hormone secretion, and other cell functions. We also briefly review the release mechanism for adenosine-5′-triphosphate by neuroendocrine, endocrine and surrounding cells, the enzymes involved in adenosine-5′-triphosphate hydrolysis to adenosine-5′-diphosphate and adenosine, and the relevance of this pathway for sequential activation of receptors and termination of signaling. PMID:25960051

  2. Metabolic factors affecting enhanced phosphorus uptake by activated sludge.

    Science.gov (United States)

    Boughton, W H; Gottfried, R J; Sinclair, N A; Yall, I

    1971-10-01

    Activated sludges obtained from the Rilling Road plant located at San Antonio, Tex., and from the Hyperion treatment plant located at Los Angeles, Calif., have the ability to remove all of the orthophosphate normally present in Tucson sewage within 3 hr after being added to the waste water. Phosphorus removal was independent of externally supplied sources of energy and ions, since orthophosphate and (32)P radioactivity were readily removed from tap water, glass-distilled water, and deionized water. Phosphorus uptake by Rilling sludge in the laboratory appears to be wholly biological, as it has an optimum pH range (7.7 to 9.7) and an optimum temperature range (24 to 37 C). It was inhibited by HgCl(2), iodoacetic acid, p-chloromercuribenzoic acid, NaN(3), and 2, 4-dinitrophenol (compounds that affect bacterial membrane permeability, sulfhydryl enzymes, and adenosine triphosphate synthesis). Uptake was inhibited by 1% NaCl but was not affected by 10(-3)m ethylenediaminetetraacetic acid disodium salt (a chelating agent for many metallic ions).

  3. [Treatment of Paget's disease with diphosphonate (disodium ethydronate)].

    Science.gov (United States)

    Caniggia, A; Gennari, C; Guideri, R; Vattimo, A; Nardi, P

    1976-01-07

    16 patients suffering from Paget's disease were studied before, during and after 3 or 6 month treatment with disodium ethydronate (EHDP) per os. An appreciable improvement in pain symptomatology was noted and at times an evident improvement in audiometry; from the metabolic viewpoint there was a fall in serum alkaline phosphatase and urinary excretion of calcium and hydroxyproline. A study of radiocalcium kinetics demonstrated a reduction in the exchangeable calcium pool and the fractional turnover rate. Histological examination following needle biopsy of the iliac crest showed evident diminution in the active bone cell population (osteoclasts, osteoblasts) and, in certain cases, appearance of osteoid borders.

  4. Adenosine Receptors and Wound Healing

    Directory of Open Access Journals (Sweden)

    Bruce N. Cronstein

    2004-01-01

    Full Text Available Recent studies have demonstrated that application of topical adenosine A2A receptor agonists promotes more rapid wound closure and clinical studies are currently underway to determine the utility of topical A2A adenosine receptor agonists in the therapy of diabetic foot ulcers. The effects of adenosine A2A receptors on the cells and tissues of healing wounds have only recently been explored. We review here the known effects of adenosine A2A receptor occupancy on the cells involved in wound healing.

  5. 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. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. Adenosine and sleep

    International Nuclear Information System (INIS)

    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 1 receptors, 3 H-L-PIA binding was measured. The Bmax values for 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 3 H-L-PIA binding resulted from REM sleep deprivation and not from stress

  7. Investigation on molecular interaction of amino acids in aqueous disodium hydrogen phosphate solutions with reference to volumetric and compressibility measurements

    International Nuclear Information System (INIS)

    Kumar, Harsh; Singla, Meenu; Jindal, Rajeev

    2014-01-01

    Highlights: • Densities and speeds of sound of amino acids in aqueous disodium hydrogen phosphate. • Partial molar volumes and compressibility of transfer. • Positive values of transfer volume indicates interactions between ions of amino acids and TSC. • Ion–hydrophilic and hydrophilic–hydrophilic interactions are present. • Pair-wise interactions are dominant in the mixtures. -- Abstract: The interactions of amino acids glycine (Gly), L-alanine (Ala), and L-valine (Val) with disodium hydrogen phosphate (DSHP) as a function of temperature have been investigated by combination of volumetric and acoustic measurements. Densities (ρ) and speeds of sound (u) of amino acids in aqueous solutions of disodium hydrogen phosphate have been measured at T = (288.15, 293.15, 298.15, 303.15 and 308.15) K and atmospheric pressure. The apparent molar volume (V ϕ ), the partial molar volume (V ϕ 0 ) and standard partial molar volumes of transfer (ΔV ϕ 0 ) for amino acids from water to aqueous disodium hydrogen phosphate solutions have been calculated from density data. Partial molar adiabatic compressibility (κ ϕ,s ) and partial molar adiabatic compressibility of transfer (Δκ ϕ,S 0 ) have been calculated from speed of sound data. The pair (V AB , κ AB ) and triplet (V ABB , κ ABB ) interaction coefficient have been calculated from both the properties. The results have been explained based on competing patterns of interactions of co-solvents and the solute

  8. Nephrogenic Systemic Fibrosis Risk After Liver Magnetic Resonance Imaging With Gadoxetate Disodium in Patients With Moderate to Severe Renal Impairment

    Science.gov (United States)

    Lauenstein, Thomas; Ramirez-Garrido, Francisco; Kim, Young Hoon; Rha, Sung Eun; Ricke, Jens; Phongkitkarun, Sith; Boettcher, Joachim; Gupta, Rajan T.; Korpraphong, Pornpim; Tanomkiat, Wiwatana; Furtner, Julia; Liu, Peter S.; Henry, Maren; Endrikat, Jan

    2015-01-01

    Objective The objective of this study was to assess the risk of gadoxetate disodium in liver imaging for the development of nephrogenic systemic fibrosis (NSF) in patients with moderate to severe renal impairment. Materials and Methods We performed a prospective, multicenter, nonrandomized, open-label phase 4 study in 35 centers from May 2009 to July 2013. The study population consisted of patients with moderate to severe renal impairment scheduled for liver imaging with gadoxetate disodium. All patients received a single intravenous bolus injection of 0.025-mmol/kg body weight of liver-specific gadoxetate disodium. The primary target variable was the number of patients who develop NSF within a 2-year follow-up period. Results A total of 357 patients were included, with 85 patients with severe and 193 patients with moderate renal impairment, which were the clinically most relevant groups. The mean time period from diagnosis of renal disease to liver magnetic resonance imaging (MRI) was 1.53 and 5.46 years in the moderate and severe renal impairment cohort, respectively. Overall, 101 patients (28%) underwent additional contrast-enhanced MRI with other gadolinium-based MRI contrast agents within 12 months before the start of the study or in the follow-up. No patient developed symptoms conclusive of NSF within the 2-year follow-up. Conclusions Gadoxetate disodium in patients with moderate to severe renal impairment did not raise any clinically significant safety concern. No NSF cases were observed. PMID:25756684

  9. Circadian variations of adenosine and of its metabolism. Could adenosine be a molecular oscillator for circadian rhythms?

    Science.gov (United States)

    Chagoya de Sánchez, V

    1995-03-01

    The present review describes the biological implications of the periodic changes of adenosine concentrations in different tissues of the rat. Adenosine is a purine molecule that could have been formed in the prebiotic chemical evolution and has been preserved. The rhythmicity of this molecule, as well as its metabolism and even the presence of specific receptors, suggests a regulatory role in eukaryotic cells and in multicellular organisms. Adenosine may be considered a chemical messenger and its action could take place at the level of the same cell (autocrine), the same tissue (paracrine), or on separate organs (endocrine). Exploration of the circadian variations of adenosine was planned considering the liver as an important tissue for purine formation, the blood as a vehicle among tissues, and the brain as the possible acceptor for hepatic adenosine or its metabolites. The rats used in these studies were adapted to a dark-light cycle of 12 h with an unrestrained feeding and drinking schedule. The metabolic control of adenosine concentration in the different tissues studied through the 24-h cycle is related to the activity of adenosine-metabolizing enzyme: 5'-nucleotidase adenosine deaminase, adenosine kinase, and S-adenosylhomocysteine hydrolase. Some possibilities of the factors modulating the activity of these enzymes are commented upon. The multiphysiological action of adenosine could be mediated by several actions: (i) by interaction with extracellular and intracellular receptors and (ii) through its metabolism modulating the methylation pathway, possibly inducing physiological lipoperoxidation, or participating in the energetic homeostasis of the cell. The physiological meaning of the circadian variations of adenosine and its metabolism was focused on: maintenance of the energetic homeostasis of the tissues, modulation of membrane structure and function, regulation of fasting and feeding metabolic pattern, and its participation in the sleep-wake cycle. From

  10. Evaluation of calcium di-sodium EDTA intramuscular injection using gamma scintigraphy against heavy metal poisoning

    International Nuclear Information System (INIS)

    Kumar, N.; Soni, S.; Mehra, L.; Mittal, G.; Nishad, D.K.; Bhatnagar, A.; Singh, T.; Ahmad, F.J.

    2010-01-01

    Full text: Heavy metals become toxic when they are not metabolized by the body and accumulate in soft tissues. These metals may enter the body through food, water, air or absorption through skin when an individual is exposed to areas with high heavy metal content such as agriculture, pharmaceutical manufacturing, paint and heavy metal industries or residential settings. Majority of population commonly get affected by heavy metal poisoning. Heavy metal poisoning is more likely to result through inhalation or ingestion route. Aim of the present study is to provide an easy, effective and controlled chelating therapy against heavy metal using Ca-disodium EDTA intramuscular injection. Ca-disodium-EDTA and Sesame oil were procured from Merck, India and Sigma Aldrich, USA respectively. Ca-Na 2 EDTA radiolabeling with 99m Tc-pertechnetate was standardized using stannous ions as reducing agent. The hypothesis of present work is to maintain effective concentration of chelating agent in blood for prolong time period. To test this hypothesis, we studied 1% Ca-Na 2 EDTA blood bioavailability after intramuscular depot administration in new zealand white rabbit. The optimized radiolabeled intramuscular formulation was evaluated for its dissolution and permeation studies in isotonic buffer solution were envisaged through radiometry. Sub-acute toxicity studies were performed after a single dose intramuscular administration of 1% Ca-Na 2 EDTA in Sprague Dawley rats. Radiolabeled Ca-disodium-EDTA (>95% labeled) was found to be fairly stable up to 24 h in physiological solution (Serum) as well as in normal saline with negligible degradation of 2.5% and 5.0% respectively, thereby indicating high stability of radiolabeled product. In-vitro data indicates that control release pattern (Cmax 24 hrs) with effective concentration up to seven days. 99m Tc-CaNa 2 EDTA retention at depot site was estimated up to 3 days by scintigraphy. Subacute toxicity studies done by histopathological

  11. Carrier-free 8-azidoadenosine 5'-[γ-32P]triphosphate

    International Nuclear Information System (INIS)

    Sabbatini, G.P.; Holt, C. von

    1987-01-01

    The authors found 8-azidoadenosine 5'-diphosphate to be a phosphoryl acceptor in the enzymatic conversion of 1,3-diphosphoglyceric acid to 3-phosphoglycerate. This has allowed the synthesis in a single-step procedure carrier-free 8-azidoadenosine 5'-[γ- 32 P]triphosphate, requiring no further purification of the end product. The synthesized 8-azidoadenosine 5'-[γ- 32 P]triphosphate has been characterized and shown to meet all the criteria for a specific photoreactive ATP analogue. 14 refs.; 4 figs.; 1 table

  12. 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

  13. Three-dimensional structure of the large cytoplasmic H-4-H-5 loop of Na(+)/K(+)-ATPase deduced by restraint-based comparative modeling shows only one ATP binding site

    Czech Academy of Sciences Publication Activity Database

    Ettrich, Rüdiger; Melicherčík, M.; Teisinger, Jan; Ettrichová, Olga; Krumscheid, R.; Hofbauerová, Kateřina; Kvasnička, P.; Schoner, W.; Amler, Evžen

    2001-01-01

    Roč. 7, č. 6 (2001), s. 184-192 ISSN 0948-5023 R&D Projects: GA MŠk VS961410; GA ČR GA204/98/0468; GA AV ČR IAA7011801; GA ČR GA204/98/0416 Grant - others:IWTZ(DE) TSR-088-97; Volkswagen Foundation(DE) I/74679 Institutional research plan: CEZ:AV0Z5011922 Keywords : Sodium potassium adenosine triphosphate * tertiary structure * adenosine triphosphate binding site Subject RIV: BO - Biophysics Impact factor: 1.011, year: 2001

  14. Functional coupling between adenosine A1 receptors and G-proteins in rat and postmortem human brain membranes determined with conventional guanosine-5'-O-(3-[35S]thio)triphosphate ([35S]GTPγS) binding or [35S]GTPγS/immunoprecipitation assay.

    Science.gov (United States)

    Odagaki, Yuji; Kinoshita, Masakazu; Ota, Toshio; Meana, J Javier; Callado, Luis F; Matsuoka, Isao; García-Sevilla, Jesús A

    2018-06-01

    Adenosine signaling plays a complex role in multiple physiological processes in the brain, and its dysfunction has been implicated in pathophysiology of neuropsychiatric diseases such as schizophrenia and affective disorders. In the present study, the coupling between adenosine A 1 receptor and G-protein was assessed by means of two [ 35 S]GTPγS binding assays, i.e., conventional filtration method and [ 35 S]GTPγS binding/immunoprecipitation in rat and human brain membranes. The latter method provides information about adenosine A 1 receptor-mediated Gα i-3 activation in rat as well as human brain membranes. On the other hand, adenosine-stimulated [ 35 S]GTPγS binding determined with conventional assay derives from functional activation of Gα i/o proteins (not restricted only to Gα i-3 ) coupled to adenosine A 1 receptors. The determination of adenosine concentrations in the samples used in the present study indicates the possibility that the assay mixture under our experimental conditions contains residual endogenous adenosine at nanomolar concentrations, which was also suggested by the results on the effects of adenosine receptor antagonists on basal [ 35 S]GTPγS binding level. The effects of adenosine deaminase (ADA) on basal binding also support the presence of adenosine. Nevertheless, the varied patterns of ADA discouraged us from adding ADA into assay medium routinely. The concentration-dependent increases elicited by adenosine were determined in 40 subjects without any neuropsychiatric disorders. The increases in %E max values determined by conventional assay according to aging and postmortem delay should be taken into account in future studies focusing on the effects of psychiatric disorders on adenosine A 1 receptor/G-protein interaction in postmortem human brain tissue.

  15. Characterization of cardiac adenosine receptors using N6-phenyladenosines and a new radioligand, [125I]-(m-aminophenyl)adenosine

    International Nuclear Information System (INIS)

    Kwatra, M.M.; Hosey, M.M.; Green, R.

    1986-01-01

    The chick heart contains adenosine receptors with characteristics similar to the R adenosine receptors found in the CNS. They have synthesized several N 6 -phenyladenosines and tested their potencies for inhibiting the binding of [ 125 I](p-aminobenzyl)adenosine {[ 125 I]ABA) to chick heart membranes. Of the 12 compounds tested, N 6 -(p-aminobenzyl) adenosine (ABA) was the least potent (IC 50 ∼ 40 nM) while N 6 -(m-nitrophenyl)adenosine(MNPA) was the most potent (IC 50 ∼ 1 nM). The IC 50 of N 6 -(m-aminophenyl)adenosine(MAPA) was greater than that of N 6 -phenyladenosine(PA) while that of MNPA was less than that of PA. The effects of these electron-releasing (-NH 2 ) and electron-withdrawing (-NO 2 ) groups along with data obtained with other phenyl-substituted N 6 -phenyladenosines suggest that the electron density of the N 6 -nitrogen may affect the affinities of these compounds for the cardiac adenosine receptor. MAPA can be iodinated to produce a new ligand, [ 125 I]MAPA. This iodination, like that of ABA, increases the affinity of the compound and produces a ligand with good affinity and low nonspecific binding suitable for studies on tissues with low concentrations of adenosine receptors

  16. A quick look at biochemistry : Carbohydrate metabolism

    NARCIS (Netherlands)

    Dashty, Monireh

    2013-01-01

    In mammals, there are different metabolic pathways in cells that break down fuel molecules to transfer their energy into high energy compounds such as adenosine-5'-triphosphate (ATP), guanosine-5'-triphosphate (GTP), reduced nicotinamide adenine dinucleotide (NADH2), reduced flavin adenine

  17. Hepatoblastoma imaging with gadoxetate disodium-enhanced MRI - typical, atypical, pre- and post-treatment evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Meyers, Arthur B. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Medical College of Wisconsin, Department of Radiology, Milwaukee, WI (United States); Children' s Hospital of Wisconsin, Department of Pediatric Imaging, Milwaukee, WI (United States); Towbin, Alexander J.; Podberesky, Daniel J. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Geller, James I. [Cincinnati Children' s Hospital Medical Center, Department of Hematology/Oncology, Cincinnati, OH (United States)

    2012-07-15

    Gadoxetate disodium (Gd-EOB-DTPA) is a hepatobiliary MRI contrast agent widely used in adults for characterization of liver tumors and increasingly used in children. Hepatoblastoma is the most common primary hepatic malignancy of childhood. In this review, we describe our experience with this agent both before and after initiating therapy in children with hepatoblastoma. (orig.)

  18. Reaction of ammonium triphosphate with gadolinium nitrate in aqueous solution at 273K

    International Nuclear Information System (INIS)

    Rodicheva, G.V.; Tananaev, I.V.; Romanova, N.M.

    1982-01-01

    The solubility in the system (NW 4 ) 5 P 3 O 10 -Gd(NO 3 ) 3 - H 2 O (273 K) is studied. Depending on the reagent ratio formation of the compounds Gd 5 (P 3 O 10 ) 3 x22H 2 O, NH 4 Gd 3 (P 3 O 10 ) 2 x12H 2 O and (NH 4 ) 3 Gd 4 (P 3 O 10 ) 3 x14H 2 O is established. Gadolinium triphosphates, separated from solution, are studied using the methods of paper chromatography, X-ray diffractometry, thermography. Simultaneously with thermal dehydration of gadolinium triphosphates the processes of triphosphate decomposition and phosphate anion condensation take place. A mixture of crystalline ortho-phosphate and long- chain polyphosphate of gadolinium is the final product of thermal decomposition (1063 K) of normal and doubl e ammonium- containing gadolinium triphosphates [ru

  19. A terbium(III)-organic framework for highly selective sensing of cytidine triphosphate.

    Science.gov (United States)

    Zhao, Xi Juan; He, Rong Xing; Li, Yuan Fang

    2012-11-21

    Highly selective sensing of cytidine triphosphate (CTP) against other triphosphate nucleosides including ATP, GTP and UTP is successfully achieved with a luminescent terbium(III)-organic framework (TbOF) of [Tb(2)(2,3-pzdc)(2)(ox)(H(2)O)(2)](n) (2,3-pzdc(2-) = 2,3-pyrazinedicarboxylate, ox(2-) = oxalate).

  20. Identification and Characterization of Novel Plant Adenylate Cyclases – The Arabidopsis Thaliana Potassium Uptake Permeases

    KAUST Repository

    Al-Younis, Inas

    2018-01-01

    Adenylyl Cyclases (ACs) catalyze the formation of the key universal second messenger adenosine 3’, 5’-cyclic monophosphate (cAMP) from adenosine 5’- triphosphate. Cyclic AMP participates in several signal transduction pathways and is present

  1. The examination of urine samples for pathogenic microbes by the luciferase assay for ATP. 1: The effect of the presence of fungi, fungal like bacteria and kidney cells in urine samples

    Science.gov (United States)

    Bush, V. N.

    1973-01-01

    A method for accurately determining urinary tract infections in man is introduced. The method is based on adenosine triphosphate (ATP) concentration in urine samples after removing nonbacterial ATP. Adenosine triphosphate concentration is measured from the bioluminescent reaction of luciferase when mixed with ATP. An examination was also made of the effectiveness of rupturing agents on monkey kidney cells Candia albicans, a Rhodotorula species, and a Streptomyces species in determining whether these cells could contribute ATP to the bacterial ATP value of a urine sample.

  2. Gadoxetate disodium-induced tachypnoea and the effect of dilution method. A proof-of-concept study in mice

    Energy Technology Data Exchange (ETDEWEB)

    Akai, Hiroyuki; Yasaka, Koichiro; Kunimatsu, Akira [University of Tokyo, Department of Radiology, Institute of Medical Science, Tokyo (Japan); Nojima, Masanori [University of Tokyo, Division of Advanced Medicine Promotion, The Advanced Clinical Research Centre, Institute of Medical Science, Tokyo (Japan); Inoue, Yusuke [Kitasato University School of Medicine, Department of Diagnostic Radiology, Sagamihara, Kanagawa (Japan); Abe, Osamu [University of Tokyo, Department of Radiology, Graduate School of Medicine, Tokyo (Japan); Ohtomo, Kuni [International University of Health and Welfare, Ohtawara, Tochigi (Japan); Kiryu, Shigeru [International University of Health and Welfare Hospital, Department of Radiology, Nasushiobara, Tochigi (Japan)

    2018-02-15

    To directly investigate the rapid respiratory effect of gadoxetate disodium in an experimental study using mice. After confirming the steady respiratory state under general anaesthesia, eight mice were injected with all test agents in the following order: phosphate-buffered saline (A, control group), 1.25 mmol/kg of gadoteridol (B) or gadopentetate dimeglumine (C), or 0.31 mmol/kg of gadoxetate disodium (D, E). The experimenter was not blinded to the agents. The injection dose was fixed as 100 μL for Groups A-D and 50 μL for Group E. We continuously monitored and recorded respiratory rate (RR), peripheral oxygen saturation (SpO{sub 2}), and heart rate. The time-series changes from 0 to 30 s were compared by the linear mixed method Groups D and E showed the largest RR increase (20.6 and 20.3 breaths/min, respectively) and were significantly larger compared to Group A (3.36 breaths/min, both P<0.001). RR change of Groups D and E did not differ. RR change of Groups B and C was smaller (0.72 and 12.4 breaths/min, respectively) and did not differ statistically with Group A. Significant bradycardia was observed only in Group C (P<0.001). SpO{sub 2} was constant in all groups. Gadoxetate disodium causes a rapid tachypnoea without significant change of SpO{sub 2} and heart rate regardless of the dilution method. (orig.)

  3. AMP is an adenosine A1 receptor agonist.

    Science.gov (United States)

    Rittiner, Joseph E; Korboukh, Ilia; Hull-Ryde, Emily A; Jin, Jian; Janzen, William P; Frye, Stephen V; Zylka, Mark J

    2012-02-17

    Numerous receptors for ATP, ADP, and adenosine exist; however, it is currently unknown whether a receptor for the related nucleotide adenosine 5'-monophosphate (AMP) exists. Using a novel cell-based assay to visualize adenosine receptor activation in real time, we found that AMP and a non-hydrolyzable AMP analog (deoxyadenosine 5'-monophosphonate, ACP) directly activated the adenosine A(1) receptor (A(1)R). In contrast, AMP only activated the adenosine A(2B) receptor (A(2B)R) after hydrolysis to adenosine by ecto-5'-nucleotidase (NT5E, CD73) or prostatic acid phosphatase (PAP, ACPP). Adenosine and AMP were equipotent human A(1)R agonists in our real-time assay and in a cAMP accumulation assay. ACP also depressed cAMP levels in mouse cortical neurons through activation of endogenous A(1)R. Non-selective purinergic receptor antagonists (pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid and suramin) did not block adenosine- or AMP-evoked activation. Moreover, mutation of His-251 in the human A(1)R ligand binding pocket reduced AMP potency without affecting adenosine potency. In contrast, mutation of a different binding pocket residue (His-278) eliminated responses to AMP and to adenosine. Taken together, our study indicates that the physiologically relevant nucleotide AMP is a full agonist of A(1)R. In addition, our study suggests that some of the physiological effects of AMP may be direct, and not indirect through ectonucleotidases that hydrolyze this nucleotide to adenosine.

  4. AMP Is an Adenosine A1 Receptor Agonist*

    Science.gov (United States)

    Rittiner, Joseph E.; Korboukh, Ilia; Hull-Ryde, Emily A.; Jin, Jian; Janzen, William P.; Frye, Stephen V.; Zylka, Mark J.

    2012-01-01

    Numerous receptors for ATP, ADP, and adenosine exist; however, it is currently unknown whether a receptor for the related nucleotide adenosine 5′-monophosphate (AMP) exists. Using a novel cell-based assay to visualize adenosine receptor activation in real time, we found that AMP and a non-hydrolyzable AMP analog (deoxyadenosine 5′-monophosphonate, ACP) directly activated the adenosine A1 receptor (A1R). In contrast, AMP only activated the adenosine A2B receptor (A2BR) after hydrolysis to adenosine by ecto-5′-nucleotidase (NT5E, CD73) or prostatic acid phosphatase (PAP, ACPP). Adenosine and AMP were equipotent human A1R agonists in our real-time assay and in a cAMP accumulation assay. ACP also depressed cAMP levels in mouse cortical neurons through activation of endogenous A1R. Non-selective purinergic receptor antagonists (pyridoxalphosphate-6-azophenyl-2′,4′-disulfonic acid and suramin) did not block adenosine- or AMP-evoked activation. Moreover, mutation of His-251 in the human A1R ligand binding pocket reduced AMP potency without affecting adenosine potency. In contrast, mutation of a different binding pocket residue (His-278) eliminated responses to AMP and to adenosine. Taken together, our study indicates that the physiologically relevant nucleotide AMP is a full agonist of A1R. In addition, our study suggests that some of the physiological effects of AMP may be direct, and not indirect through ectonucleotidases that hydrolyze this nucleotide to adenosine. PMID:22215671

  5. 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

    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.

  6. Signal intensity change on unenhanced T1-weighted images in dentate nucleus and globus pallidus after multiple administrations of gadoxetate disodium: an intraindividual comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Conte, Giorgio; Minotti, Marta; De Piano, Francesca [Universita degli Studi di Milano, Postgraduation School in Radiodiagnostics, Milan (Italy); Preda, Lorenzo [Universita degli Studi di Pavia, Department of Clinical-Surgical Diagnostic and Pediatric Sciences, Pavia (Italy); National Center of Oncological Hadrontherapy (CNAO Foundation), Division of Radiology, Pavia (Italy); Cocorocchio, Emilia; Ferrucci, Pier Francesco [European Institute of Oncology, Melanoma and Sarcoma Medical Oncology Division, Milan (Italy); Raimondi, Sara [European Institute of Oncology, Division of Epidemiology and Biostatistics, Milan (Italy); Giannitto, Caterina; Petralia, Giuseppe [European Institute of Oncology, Division of Radiology, Milan (Italy); Bellomi, Massimo [European Institute of Oncology, Division of Radiology, Milan (Italy); Universita degli Studi di Milano, Oncology and Haematology/Oncology Department, Milan (Italy)

    2017-10-15

    To investigate whether there is an increased signal intensity (SI) of dentate nucleus (DN) and globus pallidus (GP) on unenhanced T1-weighted magnetic resonance imaging (MRI), in patients who had undergone multiple administrations of gadoxetate disodium. We retrospectively included stage III melanoma patients, who had been previously enrolled in a trial of adjuvant therapy and who had undergone whole-body contrast-enhanced MRIs with gadoxetate disodium every three months for their follow-up. The SI ratios of DN-to-pons and GP-to-thalamus on unenhanced T1-weighted images were calculated. The difference in SI ratios between the first and the last MRI examinations was assessed and a linear mixed model was performed to detect how SI ratios varied with the number of administrations. Eighteen patients were included in our study. The number of gadoxetate disodium administrations ranged from 2 to 18. Paired t-test did not show any significant difference in DN-to-pons (p=0.21) and GP-to-thalamus (p=0.09) SI ratios by the end of the study. DN-to-pons SI ratio and GP-to-thalamus SI ratio did not significantly increase with increasing the number of administrations (p=0.14 and p=0.06, respectively). Multiple administrations of gadoxetate disodium are not associated with increased SI in DN and GP in the brain. (orig.)

  7. A2A adenosine receptor ligand binding and signalling is allosterically modulated by adenosine deaminase.

    Science.gov (United States)

    Gracia, Eduard; Pérez-Capote, Kamil; Moreno, Estefanía; Barkešová, Jana; Mallol, Josefa; Lluís, Carme; Franco, Rafael; Cortés, Antoni; Casadó, Vicent; Canela, Enric I

    2011-05-01

    A2ARs (adenosine A2A receptors) are highly enriched in the striatum, which is the main motor control CNS (central nervous system) area. BRET (bioluminescence resonance energy transfer) assays showed that A2AR homomers may act as cell-surface ADA (adenosine deaminase; EC 3.5.4.4)-binding proteins. ADA binding affected the quaternary structure of A2ARs present on the cell surface. ADA binding to adenosine A2ARs increased both agonist and antagonist affinity on ligand binding to striatal membranes where these proteins are co-expressed. ADA also increased receptor-mediated ERK1/2 (extracellular-signal-regulated kinase 1/2) phosphorylation. Collectively, the results of the present study show that ADA, apart from regulating the concentration of extracellular adenosine, may behave as an allosteric modulator that markedly enhances ligand affinity and receptor function. This powerful regulation may have implications for the physiology and pharmacology of neuronal A2ARs.

  8. Measurement of plasma adenosine concentration: methodological and physiological considerations

    International Nuclear Information System (INIS)

    Gewirtz, H.; Brown, P.; Most, A.S.

    1987-01-01

    This study tested the hypothesis that measurements of plasma adenosine concentration made on samples of blood obtained in dipyridamole and EHNA (i.e., stopping solution) may be falsely elevated as a result of ongoing in vitro production and accumulation of adenosine during sample processing. Studies were performed with samples of anticoagulated blood obtained from anesthesized domestic swine. Adenosine concentration of ultra filtrated plasma was determined by HPLC. The following parameters were evaluated: (i) rate of clearance of [ 3 H]adenosine added to plasma, (ii) endogenous adenosine concentration of matched blood samples obtained in stopping solution alone, stopping solution plus EDTA, and perchloric acid (PCA), (iii) plasma and erythrocyte endogenous adenosine concentration in nonhemolyzed samples, and (iv) plasma adenosine concentration of samples hemolyzed in the presence of stopping solution alone or stopping solution plus EDTA. We observed that (i) greater than or equal to 95% of [ 3 H]adenosine added to plasma is removed from it by formed elements of the blood in less than 20 s, (ii) plasma adenosine concentration of samples obtained in stopping solution alone is generally 10-fold greater than that of matched samples obtained in stopping solution plus EDTA, (iii) deliberate mechanical hemolysis of blood samples obtained in stopping solution alone resulted in substantial augmentation of plasma adenosine levels in comparison with matched nonhemolyzed specimens--addition of EDTA to stopping solution prevented this, and (iv) adenosine content of blood samples obtained in PCA agreed closely with the sum of plasma and erythrocyte adenosine content of samples obtained in stopping solution plus EDTA

  9. The impact of adenosine pharmacologic stress combined with low-level exercise in patients undergoing myocardial perfusion imaging (BIWAKO adenosine-Ex trial)

    International Nuclear Information System (INIS)

    Monzen, Hajime; Hara, Masatake; Hirata, Makoto

    2011-01-01

    The combination of adenosine infusion with low-level exercise has become a common approach for inducing stress during stress myocardial perfusion imaging (MPI). We investigated stress MPI performed by combined low-level exercise and adenosine infusion. This combined protocol can decrease adverse reactions and reduce the effect of scattered rays from the liver. Subjects were clinically referred for a 53-min rest-stress Tc-99m Sestamibi MPI procedure using BIWAKO PROTOCOL. Ninety-eight patients (44.5%) underwent adenosine infusion with ergometer exercise testing and 122 patients (55.5%) underwent adenosine infusion without exercise testing. We evaluated the liver/heart (L/H) uptake ratio, background activity in the upper mediastinum, and adverse reactions. The L/H ratio and background activity were lower in the adenosine-exercise group than in the adenosine-non-exercise group (1.8±0.54 vs. 2.1±0.62, P<0.0056; 43.1±12.2 vs. 61.5±15.4, P<0.0001). The adenosine-exercise group had fewer adverse reactions than the adenosine-non-exercise group (11.2 vs. 19.7%). All of the adverse reactions were minor, with the exception of severe back pain in one case. The incidence of adverse reactions in our study was lower than that in previous studies for unknown reason. Adenosine infusion in combination with low-level exercise seems to result in higher-quality images and fewer adverse reactions than adenosine infusion without exercise. The combined protocol decreases adverse reactions and improves the quality of myocardial perfusion images by decreasing background activity. (author)

  10. Adenosine: a putative mediator of bronchoconstriction in asthma

    Energy Technology Data Exchange (ETDEWEB)

    Mann, J.S.

    1987-01-01

    The protective effect of a muscarinic cholinergic antagonists, ipratropium bromide (IB) from inhaled adenosine- and methacholine-induced bronchoconstriction in asthma was studied. Inhaled IB protected from methacholine- but not adenosine-induced bronchoconstriction. Parasympathetically mediated bronchoconstriction is therefore unlikely to account for adenosine's airway effect in asthma. The capacity of theophylline, a bronchodilator and a competitive antagonist of adenosine at its cell surface receptors, to protect asthmatic subjects from adenosine- and histamine-induced bronchoconstriction was determined. Asthmatic airways are infiltrated with inflammatory cells. Human leucocytes prelabeled with (/sup 3/H)-adenine when activated with the calcium ionophore A23187 released labelled hypoxanthine, inosine and adenosine which was associated with a dose-related release of histamine. The chemotactic peptide f-MLP while inducing histamine release had an inconstant effect on release of label. In four of five experiments f-MLP produced a transient early increase in label release but in the remaining experiment no significant release was observed. Anti-human IgE failed to induce significant label release despite releasing histamine. Activated leucocytes are therefore a potential source of adenosine in asthma.

  11. Method for enzyme synthesis of radioactive thymine 5'-deoxyribonucleotides

    International Nuclear Information System (INIS)

    Nejedly, Z.; Ekl, J.; Hybs, K.; Kolina, J.; Filip, J.; Votruba, I.; Skoda, J.

    1978-01-01

    The enzyme synthesis is described for thymidine-5'-monophosphate, thymidine-5'-diphosphate and thymidine-5'-triphosphate specifically or nonspecifically labelled with 14 C or 3 H. The anabolic transformation of radioactive thymine to radioactive thymine 5'-deoxyribonucleotides is catalyzed by the action of enzyme preparations separated from Escherichia coli bacteria. It is achieved by the action of nonpurified cell-free extracts on special auxotrophic mutants of the thymine-dependent Escherichia coli SPT - strain in the presence of deoxyriboso-1-phosphate and adenosine-5'-triphosphate. The radioactive thymidine-5'-monophosphate may further be phosphorylated. In reaction mixtures, radioactive thymine, deoxyriboso-1-phosphate and adenosine-5'-triphosphate are used in molar ratios of 1:1:2 to 1:10:100, the optimum molar ratio being 1:5:10. (B.S.)

  12. Enhanced vasculotoxic metal excretion in post-myocardial infarction patients following a single edetate disodium-based infusion.

    Science.gov (United States)

    Arenas, Ivan A; Navas-Acien, Ana; Ergui, Ian; Lamas, Gervasio A

    2017-10-01

    Toxic metals have been associated with cardiovascular mortality and morbidity. We have hypothesized that enhanced excretion of vasculotoxic metals might explain the positive results of the Trial to Assess Chelation Therapy (TACT). The purpose of this study was to determine whether a single infusion of the edetate disodium- based infusion used in TACT led to enhanced excretion of toxic metals known to be associated with cardiovascular events. Twenty six patients (post-MI, age > 50 years, serum creatinine ≤ 2.0mg/dL) were enrolled in this open-label study. Urinary levels of 20 toxic metals normalized to urinary creatinine concentrations were measured at baseline in overnight urine collections, for 6h following a placebo infusion of 500mL normal saline and 1.2% dextrose, and for 6h following a 3g edetate disodium-based infusion. Self-reported metal exposure, smoking status, food frequency, occupational history, drinking water source, housing and hobbies were collected at baseline by a metal exposure questionnaire. The mean age was 65 years (range 51-81 years). All patients were male. 50% had diabetes mellitus and 58% were former smokers. Mean (SD) serum creatinine was 0.95 (0.31) mg/dL. Toxic metals were detected in the baseline urine of >80% of patients. After placebo infusion there were no significant changes in total urinary metal levels. After edetate infusion, total urinary metal level increased by 71% compared to baseline (1500 vs. 2580µg/g creatinine; P<0.0001). The effect of edetate was particularly large for lead (3835% increase) and cadmium (633% increase). Edetate disodium-based infusions markedly enhanced the urinary excretion of lead and cadmium, toxic metals with established epidemiologic evidence and mechanisms linking them to coronary and vascular events. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. 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.

  14. Age-associated metabolic and morphologic changes in mitochondria of individual mouse and hamster oocytes.

    Directory of Open Access Journals (Sweden)

    Fatma Simsek-Duran

    Full Text Available BACKGROUND: In human oocytes, as in other mammalian ova, there is a significant variation in the pregnancy potential, with approximately 20% of oocyte-sperm meetings resulting in pregnancies. This frequency of successful fertilization decreases as the oocytes age. This low proportion of fruitful couplings appears to be influenced by changes in mitochondrial structure and function. In this study, we have examined mitochondrial biogenesis in both hamster (Mesocricetus auratus and mouse (Mus musculus ova as models for understanding the effects of aging on mitochondrial structure and energy production within the mammalian oocyte. METHODOLOGY/PRINCIPAL FINDINGS: Individual metaphase II oocytes from a total of 25 young and old mice and hamsters were collected from ovarian follicles after hormone stimulation and prepared for biochemical or structural analysis. Adenosine triphosphate levels and mitochondrial DNA number were determined within individual oocytes from young and old animals. In aged hamsters, oocyte adenosine triphosphate levels and mitochondrial DNA molecules were reduced 35.4% and 51.8%, respectively. Reductions of 38.4% and 44% in adenosine triphosphate and mitochondrial genomes, respectively, were also seen in aged mouse oocytes. Transmission electron microscopic (TEM analysis showed that aged rodent oocytes had significant alterations in mitochondrial and cytoplasmic lamellae structure. CONCLUSIONS/SIGNIFICANCE: In both mice and hamsters, decreased adenosine triphosphate in aged oocytes is correlated with a similar decrease in mtDNA molecules and number of mitochondria. Mitochondria in mice and hamsters undergo significant morphological change with aging including mitochondrial vacuolization, cristae alterations, and changes in cytoplasmic lamellae.

  15. Ischaemic tolerance in aged mouse myocardium: the role of adenosine and effects of A1 adenosine receptor overexpression

    Science.gov (United States)

    Headrick, John P; Willems, Laura; Ashton, Kevin J; Holmgren, Kirsten; Peart, Jason; Matherne, G Paul

    2003-01-01

    The genesis of the ischaemia intolerant phenotype in aged myocardium is poorly understood. We tested the hypothesis that impaired adenosine-mediated protection contributes to ischaemic intolerance, and examined whether this is countered by A1 adenosine receptor (A1AR) overexpression. Responses to 20 min ischaemia and 45 min reperfusion were assessed in perfused hearts from young (2–4 months) and moderately aged (16–18 months) mice. Post-ischaemic contractility was impaired by ageing with elevated ventricular diastolic (32 ± 2 vs. 18 ± 2 mmHg in young) and reduced developed (37 ± 3 vs. 83 ± 6 mmHg in young) pressures. Lactate dehydrogenase (LDH) loss was exaggerated (27 ± 2 vs. 16 ± 2 IU g−1in young) whereas the incidence of tachyarrhythmias was similar in young (15 ± 1 %) and aged hearts (16 ± 1 %). Functional analysis confirmed equipotent effects of 50 μm adenosine at A1 and A2 receptors in young and aged hearts. Nonetheless, while 50 μm adenosine improved diastolic (5 ± 1 mmHg) and developed pressures (134 ± 7 mmHg) and LDH loss (6 ± 2 IU g−1) in young hearts, it did not alter these variables in the aged group. Adenosine did attenuate arrhythmogenesis for both ages (to ∼10 %). In contrast to adenosine, 50 μm diazoxide reduced ischaemic damage and arrhythmogenesis for both ages. Contractile and anti-necrotic effects of adenosine were limited by 100 μm 5-hydroxydecanoate (5-HD) and 3 μm chelerythrine. Anti-arrhythmic effects were limited by 5-HD but not chelerythrine. Non-selective (100 μm 8-sulfophenyltheophylline) and A1-selective (150 nm 8-cyclopentyl-1,3-dipropylxanthine) adenosine receptor antagonism impaired ischaemic tolerance in young but not aged hearts. Quantitative real-time PCR and radioligand analysis indicated that impaired protection is unrelated to changes in A1AR mRNA transcription, or receptor density (∼8 fmol mg−1 protein in both age groups). However, A1AR overexpression improved tolerance for both ages, restoring

  16. Mechanism-specific effects of adenosine on ventricular tachycardia.

    Science.gov (United States)

    Lerman, Bruce B; Ip, James E; Shah, Bindi K; Thomas, George; Liu, Christopher F; Ciaccio, Edward J; Wit, Andrew L; Cheung, Jim W; Markowitz, Steven M

    2014-12-01

    There is no universally accepted method by which to diagnose clinical ventricular tachycardia (VT) due to cAMP-mediated triggered activity. Based on cellular and clinical data, adenosine termination of VT is thought to be consistent with a diagnosis of triggered activity. However, a major gap in evidence mitigates the validity of this proposal, namely, defining the specificity of adenosine response in well-delineated reentrant VT circuits. To this end, we systematically studied the effects of adenosine in a model of canine reentrant VT and in human reentrant VT, confirmed by 3-dimensional, pace- and substrate mapping. Adenosine (12 mg [IQR 12-24]) failed to terminate VT in 31 of 31 patients with reentrant VT due to structural heart disease, and had no effect on VT cycle length (age, 67 years [IQR 53-74]); ejection fraction, 35% [IQR 20-55]). In contrast, adenosine terminated VT in 45 of 50 (90%) patients with sustained focal right or left outflow tract tachycardia. The sensitivity of adenosine for identifying VT due to triggered activity was 90% (95% CI, 0.78-0.97) and its specificity was 100% (95% CI, 0.89-1.0). Additionally, reentrant circuits were mapped in the epicardial border zone of 4-day-old infarcts in mongrel dogs. Adenosine (300-400 μg/kg) did not terminate sustained VT or have any effect on VT cycle length. These data support the concept that adenosine's effects on ventricular myocardium are mechanism specific, such that termination of VT in response to adenosine is diagnostic of cAMP-mediated triggered activity. © 2014 Wiley Periodicals, Inc.

  17. Enhancement patterns and pseudo-washout of hepatic haemangiomas on gadoxetate disodium-enhanced liver MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bohyun [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea, Republic of); Ajou University School of Medicine, Department of Radiology, Suwon (Korea, Republic of); Byun, Jae Ho; Kim, Hyoung Jung; Won, Hyung Jin; Kim, So Yeon; Shin, Yong Moon; Kim, Pyo Nyun [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea, Republic of)

    2016-01-15

    To compare the enhancement patterns and prevalence of pseudo-washout between rapidly and slowly enhancing hepatic haemangiomas on gadoxetate disodium-enhanced MRI in patients with chronic liver disease (CLD) and healthy liver (HL). On gadoxetate disodium-enhanced MRI, the extent of intralesional arterial enhancement >50 % and ≤50 % of lesions was defined as rapid and slow enhancement, respectively. The enhancement patterns and presence of pseudo-washout during the portal venous phase (PVP) and transitional phase (TP) of 74 hepatic haemangiomas were retrospectively evaluated in the CLD and HL groups. Sequential changes of signal-to-noise ratio (SNR) were measured in unenhanced phase, PVP and TP. Irrespective of hepatic health status, pseudo-washout in TP was significantly more common in the rapidly enhancing haemangiomas (p ≤ 0.026). In both groups, rapidly enhancing haemangiomas showed complete or progressive incomplete enhancement in PVP, which either lasted or transformed to pseudo-washout in TP, whereas slowly enhancing haemangiomas showed progressive incomplete enhancement in PVP and TP. SNR of hepatic parenchyma continued to rise until TP, whereas that of portal vein and haemangioma falls in TP. Regardless of CLD, pseudo-washout in TP was more common in rapidly than in slowly enhancing haemangiomas, with enhancement patterns differing in the two subgroups. (orig.)

  18. Enhancement patterns and pseudo-washout of hepatic haemangiomas on gadoxetate disodium-enhanced liver MRI

    International Nuclear Information System (INIS)

    Kim, Bohyun; Byun, Jae Ho; Kim, Hyoung Jung; Won, Hyung Jin; Kim, So Yeon; Shin, Yong Moon; Kim, Pyo Nyun

    2016-01-01

    To compare the enhancement patterns and prevalence of pseudo-washout between rapidly and slowly enhancing hepatic haemangiomas on gadoxetate disodium-enhanced MRI in patients with chronic liver disease (CLD) and healthy liver (HL). On gadoxetate disodium-enhanced MRI, the extent of intralesional arterial enhancement >50 % and ≤50 % of lesions was defined as rapid and slow enhancement, respectively. The enhancement patterns and presence of pseudo-washout during the portal venous phase (PVP) and transitional phase (TP) of 74 hepatic haemangiomas were retrospectively evaluated in the CLD and HL groups. Sequential changes of signal-to-noise ratio (SNR) were measured in unenhanced phase, PVP and TP. Irrespective of hepatic health status, pseudo-washout in TP was significantly more common in the rapidly enhancing haemangiomas (p ≤ 0.026). In both groups, rapidly enhancing haemangiomas showed complete or progressive incomplete enhancement in PVP, which either lasted or transformed to pseudo-washout in TP, whereas slowly enhancing haemangiomas showed progressive incomplete enhancement in PVP and TP. SNR of hepatic parenchyma continued to rise until TP, whereas that of portal vein and haemangioma falls in TP. Regardless of CLD, pseudo-washout in TP was more common in rapidly than in slowly enhancing haemangiomas, with enhancement patterns differing in the two subgroups. (orig.)

  19. Method for extending the useful shelf-life of refrigerated red blood cells by flushing with inert gas

    Science.gov (United States)

    Bitensky, Mark W.; Yoshida, Tatsuro

    1997-01-01

    Method using oxygen removal for extending the useful shelf-life of refrigerated red blood cells. A cost-effective, 4.degree. C. storage procedure that preserves red cell quality and prolongs post-transfusion in vivo survival is described. Preservation of adenosine triphosphate levels and reduction in hemolysis and in membrane vesicle production of red blood cells stored at 4.degree. C. for prolonged periods of time is achieved by removing oxygen therefrom at the time of storage; in particular, by flushing with an inert gas. Adenosine triphosphate levels of the stored red blood cells are boosted in some samples by addition of ammonium phosphate.

  20. 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

  1. Effects of adenosine infusion into renal interstitium on renal hemodynamics

    International Nuclear Information System (INIS)

    Pawlowska, D.; Granger, J.P.; Knox, F.G.

    1987-01-01

    This study was designed to investigate the hemodynamic effects of exogenous adenosine in the interstitium of the rat kidney. Adenosine or its analogues were infused into the renal interstitium by means of chronically implanted capsules. In fusion of adenosine decreased glomerular filtration rate (GFR) from 0.81 +/- 0.06 to 0.37 +/- 0.06 ml/min while having no effect on renal blood flow (RBF). The metabolically stable analogue, 2-chloradenosine (2-ClAdo), decreased GFR from 0.73 +/- 0.07 to 021 +/- 0.06 ml/min. Interstitial infusion of theophylline, an adenosine receptor antagonist, completely abolished the effects of adenosine and 2-ClAdo on GFR. The distribution of adenosine, when infused into the renal interstitium, was determined using radiolabeled 5'-(N-ethyl)-carboxamidoadenosine (NECA), a metabolically stable adenosine agonist. After continuous infusion, [ 3 H]NECA was distributed throughout the kidney. The effects of NECA to reduce GFR were similar to those of adenosine and 2-ClAdo. They conclude that increased levels of adenosine in the renal interstitium markedly decrease GFR without affecting RBF in steady-state conditions. The marked effects of adenosine agonists during their infusion into the renal interstitium and the complete blockade of these effects by theophylline suggest an extracellular action of adenosine

  2. Role of adenosine receptors in caffeine tolerance

    International Nuclear Information System (INIS)

    Holtzman, S.G.; Mante, S.; Minneman, K.P.

    1991-01-01

    Caffeine is a competitive antagonist at adenosine receptors. Receptor up-regulation during chronic drug treatment has been proposed to be the mechanism of tolerance to the behavioral stimulant effects of caffeine. This study reassessed the role of adenosine receptors in caffeine tolerance. Separate groups of rats were given scheduled access to drinking bottles containing plain tap water or a 0.1% solution of caffeine. Daily drug intake averaged 60-75 mg/kg and resulted in complete tolerance to caffeine-induced stimulation of locomotor activity, which could not be surmounted by increasing the dose of caffeine. 5'-N-ethylcarboxamidoadenosine (0.001-1.0 mg/kg) dose dependently decreased the locomotor activity of caffeine-tolerant rats and their water-treated controls but was 8-fold more potent in the latter group. Caffeine (1.0-10 mg/kg) injected concurrently with 5-N-ethylcarboxamidoadenosine antagonized the decreases in locomotor activity comparably in both groups. Apparent pA2 values for tolerant and control rats also were comparable: 5.05 and 5.11. Thus, the adenosine-antagonist activity of caffeine was undiminished in tolerant rats. The effects of chronic caffeine administration on parameters of adenosine receptor binding and function were measured in cerebral cortex. There were no differences between brain tissue from control and caffeine-treated rats in number and affinity of adenosine binding sites or in receptor-mediated increases (A2 adenosine receptor) and decreases (A1 adenosine receptor) in cAMP accumulation. These results are consistent with theoretical arguments that changes in receptor density should not affect the potency of a competitive antagonist. Experimental evidence and theoretical considerations indicate that up-regulation of adenosine receptors is not the mechanism of tolerance to caffeine-induced stimulation of locomotor activity

  3. Role of adenosine receptors in caffeine tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Holtzman, S.G.; Mante, S.; Minneman, K.P. (Emory Univ. School of Medicine, Atlanta, GA (USA))

    1991-01-01

    Caffeine is a competitive antagonist at adenosine receptors. Receptor up-regulation during chronic drug treatment has been proposed to be the mechanism of tolerance to the behavioral stimulant effects of caffeine. This study reassessed the role of adenosine receptors in caffeine tolerance. Separate groups of rats were given scheduled access to drinking bottles containing plain tap water or a 0.1% solution of caffeine. Daily drug intake averaged 60-75 mg/kg and resulted in complete tolerance to caffeine-induced stimulation of locomotor activity, which could not be surmounted by increasing the dose of caffeine. 5'-N-ethylcarboxamidoadenosine (0.001-1.0 mg/kg) dose dependently decreased the locomotor activity of caffeine-tolerant rats and their water-treated controls but was 8-fold more potent in the latter group. Caffeine (1.0-10 mg/kg) injected concurrently with 5-N-ethylcarboxamidoadenosine antagonized the decreases in locomotor activity comparably in both groups. Apparent pA2 values for tolerant and control rats also were comparable: 5.05 and 5.11. Thus, the adenosine-antagonist activity of caffeine was undiminished in tolerant rats. The effects of chronic caffeine administration on parameters of adenosine receptor binding and function were measured in cerebral cortex. There were no differences between brain tissue from control and caffeine-treated rats in number and affinity of adenosine binding sites or in receptor-mediated increases (A2 adenosine receptor) and decreases (A1 adenosine receptor) in cAMP accumulation. These results are consistent with theoretical arguments that changes in receptor density should not affect the potency of a competitive antagonist. Experimental evidence and theoretical considerations indicate that up-regulation of adenosine receptors is not the mechanism of tolerance to caffeine-induced stimulation of locomotor activity.

  4. Turnover of adenosine in plasma of human and dog blood

    International Nuclear Information System (INIS)

    Moeser, G.H.S.; Schrader, J.; Deussen, A.

    1989-01-01

    To determine half-life and turnover of plasma adenosine, heparinized blood from healthy volunteers was incubated with radiolabeled adenosine in the physiological concentration range of 0.1-1 microM. Plasma levels of adenosine in vitro were 82 +/- 14 nM and were similar to those determined immediately after blood collection with a ''stopping solution.'' Dipyridamole (83 microM) and erythro-9(2-hydroxynon-3yl)-adenine (EHNA) (8 microM) did not measurably alter basal adenosine levels but completely blocked the uptake of added adenosine. Inhibition of ecto-5'-nucleotidase with 100 microM alpha, beta-methyleneadenosine 5'-diphosphate (AOPCP) reduced plasma adenosine to 22 +/- 6 nM. For the determination of adenosine turnover, the decrease in specific radioactivity of added [ 3 H]adenosine was measured using a dipyridamole-containing stopping solution. Without altering basal adenosine levels, the half-life was estimated to be 0.6 s. Similar experiments were carried out with washed erythrocytes or in the presence of AOPCP, yielding half-lives of 0.7 and 0.9 s, respectively. When the initial adenosine concentration was 1 microM, its specific activity decreased by only 11% within 5 s, whereas total plasma adenosine exponentially decreased with a half-life of 1.5 s. Venous plasma concentrations were measured after relief of a 3-min forearm ischemia. Changes in plasma adenosine did not correlate well with changes in blood flow but were augmented in the presence of dipyridamole

  5. Labelled radioactive adenosinphosphates for the determination of toxic action

    International Nuclear Information System (INIS)

    Tahbaz, Z.

    1983-01-01

    Normal house-flies had been fed with carrier free radiophosphate (phosphorus). Many phosphorous containing substances in the tissue of the housefly are labelled with radiophosphorus by this procedure. Radiophosphorus is also found in the nucleotides of the housefly after applying radioactive phosphate. Suitable methods for processing and separation had been selected and worked out to isolate 32 P-adenosin-triphosphate 32 P-adenosin-diphosphate, 32 P-adenosin-monophosphate and 32 P-phosphate. Working at low temperature prevents chemical changes of the nucleotides. Extraction and thin layer chromatorgraphy turned out to be effective separation procedures for preparing samples for radioactivity measurement of the nucleotides. Autoradiographic techniques, scanning and liquid scitillation counting had been used for radioactivity measurements of the radioactive zones at the chromatograms. The results of these measurements provide information concerning the normal composition of adenosin-phosphates in the tissues of the housefly. If the animals are exposed to toxic chemicals, to insecticides, the composition of the phosphate containing compounds is changing. The concentration of adenosin-triphosphate is decreasing and the concentration of phosphate is increasing. This can be very easily shown by scanning the chromatograms of the extracts of the muscles of houseflies after feeding the animals with radioactive phosphate. Using this method, it is possible to show the toxic action of insecticides upon the metabolism of adenosin-phosphates. The decrease of the radioactivity at the zone of the adenosin-triphosphate and the increase of the radioactivity at the phosphate zone corresponds to the toxic action of foreign chemicals like insecticides. By using this tracer technique, it may be possible to investigate the toxic action of several toxic chemicals, if they are applied at the same time, thus investigating synergetic actions of environmental poisons. (Author)

  6. An Adenosine-Mediated Glial-Neuronal Circuit for Homeostatic Sleep.

    Science.gov (United States)

    Bjorness, Theresa E; Dale, Nicholas; Mettlach, Gabriel; Sonneborn, Alex; Sahin, Bogachan; Fienberg, Allen A; Yanagisawa, Masashi; Bibb, James A; Greene, Robert W

    2016-03-30

    Sleep homeostasis reflects a centrally mediated drive for sleep, which increases during waking and resolves during subsequent sleep. Here we demonstrate that mice deficient for glial adenosine kinase (AdK), the primary metabolizing enzyme for adenosine (Ado), exhibit enhanced expression of this homeostatic drive by three independent measures: (1) increased rebound of slow-wave activity; (2) increased consolidation of slow-wave sleep; and (3) increased time constant of slow-wave activity decay during an average slow-wave sleep episode, proposed and validated here as a new index for homeostatic sleep drive. Conversely, mice deficient for the neuronal adenosine A1 receptor exhibit significantly decreased sleep drive as judged by these same indices. Neuronal knock-out of AdK did not influence homeostatic sleep need. Together, these findings implicate a glial-neuronal circuit mediated by intercellular Ado, controlling expression of homeostatic sleep drive. Because AdK is tightly regulated by glial metabolic state, our findings suggest a functional link between cellular metabolism and sleep homeostasis. The work presented here provides evidence for an adenosine-mediated regulation of sleep in response to waking (i.e., homeostatic sleep need), requiring activation of neuronal adenosine A1 receptors and controlled by glial adenosine kinase. Adenosine kinase acts as a highly sensitive and important metabolic sensor of the glial ATP/ADP and AMP ratio directly controlling intracellular adenosine concentration. Glial equilibrative adenosine transporters reflect the intracellular concentration to the extracellular milieu to activate neuronal adenosine receptors. Thus, adenosine mediates a glial-neuronal circuit linking glial metabolic state to neural-expressed sleep homeostasis. This indicates a metabolically related function(s) for this glial-neuronal circuit in the buildup and resolution of our need to sleep and suggests potential therapeutic targets more directly related to

  7. Adenosine contribution to normal renal physiology and chronic kidney disease.

    Science.gov (United States)

    Oyarzún, Carlos; Garrido, Wallys; Alarcón, Sebastián; Yáñez, Alejandro; Sobrevia, Luis; Quezada, Claudia; San Martín, Rody

    2017-06-01

    Adenosine is a nucleoside that is particularly interesting to many scientific and clinical communities as it has important physiological and pathophysiological roles in the kidney. The distribution of adenosine receptors has only recently been elucidated; therefore it is likely that more biological roles of this nucleoside will be unveiled in the near future. Since the discovery of the involvement of adenosine in renal vasoconstriction and regulation of local renin production, further evidence has shown that adenosine signaling is also involved in the tubuloglomerular feedback mechanism, sodium reabsorption and the adaptive response to acute insults, such as ischemia. However, the most interesting finding was the increased adenosine levels in chronic kidney diseases such as diabetic nephropathy and also in non-diabetic animal models of renal fibrosis. When adenosine is chronically increased its signaling via the adenosine receptors may change, switching to a state that induces renal damage and produces phenotypic changes in resident cells. This review discusses the physiological and pathophysiological roles of adenosine and pays special attention to the mechanisms associated with switching homeostatic nucleoside levels to increased adenosine production in kidneys affected by CKD. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Radio-chromatographic determination of plasmatic adenosine deaminase (A.D.); Determination radiochromatographique de l'adenosine deaminase (A.D.)

    Energy Technology Data Exchange (ETDEWEB)

    Chivot, J J; Depernet, D; Caen, J [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes

    1970-07-01

    We were able, by using a radio-chromatographic method, to measure an adenosine deaminase activity in normal human heparinized platelet-poor plasma, which can degrade 0.016 {mu}M adenosine. This activity suppressed by heating 56 C for 30 minutes is inhibited by high concentrations of urea and is proportional to the amount of plasma, source of enzyme, in the systems. (authors) [French] Nous avons pu, en utilisant une methode radiochromatographique, mesurer une activite adenosine deaminasique dans le plasma humain pauvre en plaquettes heparine qui peut degrader 0,016 {mu}M d'adenosine. Cette activite qui est supprimee par chauffage a 56 degres pendant 30 minutes, est reduite par conservation a -20 C pendant une semaine, est inhibee par d'importantes concentrations d'uree et ne l'est pas, ni par le dipyridamol, ni par le pHMB. Cette activite est proportionnelle a la quantite de plasma, source d'enzyme, mise dans les differents systemes reactifs. (auteur)

  9. Adenosine A2A receptors in the nucleus accumbens bi-directionally alter cocaine seeking in rats.

    Science.gov (United States)

    O'Neill, Casey E; LeTendre, McKenzie L; Bachtell, Ryan K

    2012-04-01

    Repeated cocaine administration enhances dopamine D(2) receptor sensitivity in the mesolimbic dopamine system, which contributes to drug relapse. Adenosine A(2A) receptors are colocalized with D(2) receptors on nucleus accumbens (NAc) medium spiny neurons where they antagonize D(2) receptor activity. Thus, A(2A) receptors represent a target for reducing enhanced D(2) receptor sensitivity that contributes to cocaine relapse. The aim of these studies were to determine the effects of adenosine A(2A) receptor modulation in the NAc on cocaine seeking in rats that were trained to lever press for cocaine. Following at least 15 daily self-administration sessions and 1 week of abstinence, lever pressing was extinguished in daily extinction sessions. We subsequently assessed the effects of intra-NAc core microinjections of the A(2A) receptor agonist, CGS 21680 (4-[2-[[6-amino-9-(N-ethyl-b-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzenepropanoic acid hydrochloride), and the A(2A) receptor antagonist, MSX-3 (3,7-dihydro-8-[(1E)-2-(3-methoxyphenyl)ethenyl]-7-methyl-3-[3-(phosphonooxy)propyl-1-(2-propynyl)-1H-purine-2,6-dione disodium salt hydrate), in modulating cocaine- and quinpirole-induced reinstatement to cocaine seeking. Intra-NAc pretreatment of CGS 21680 reduced both cocaine- and quinpirole-induced reinstatement. These effects were specific to cocaine reinstatement as intra-NAc CGS 21680 had no effect on sucrose seeking in rats trained to self-administer sucrose pellets. Intra-NAc treatment with MSX-3 modestly reinstated cocaine seeking when given alone, and exacerbated both cocaine- and quinpirole-induced reinstatement. Interestingly, the exacerbation of cocaine seeking produced by MSX-3 was only observed at sub-threshold doses of cocaine and quinpirole, suggesting that removing tonic A(2A) receptor activity enables behaviors mediated by dopamine receptors. Taken together, these findings suggest that A(2A) receptor stimulation reduces, while A(2A) blockade

  10. Adenosine A2A Receptors in the Nucleus Accumbens Bi-Directionally Alter Cocaine Seeking in Rats

    Science.gov (United States)

    O'Neill, Casey E; LeTendre, Mckenzie L; Bachtell, Ryan K

    2012-01-01

    Repeated cocaine administration enhances dopamine D2 receptor sensitivity in the mesolimbic dopamine system, which contributes to drug relapse. Adenosine A2A receptors are colocalized with D2 receptors on nucleus accumbens (NAc) medium spiny neurons where they antagonize D2 receptor activity. Thus, A2A receptors represent a target for reducing enhanced D2 receptor sensitivity that contributes to cocaine relapse. The aim of these studies were to determine the effects of adenosine A2A receptor modulation in the NAc on cocaine seeking in rats that were trained to lever press for cocaine. Following at least 15 daily self-administration sessions and 1 week of abstinence, lever pressing was extinguished in daily extinction sessions. We subsequently assessed the effects of intra-NAc core microinjections of the A2A receptor agonist, CGS 21680 (4-[2-[[6-amino-9-(N-ethyl-b--ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzenepropanoic acid hydrochloride), and the A2A receptor antagonist, MSX-3 (3,7-dihydro-8-[(1E)-2-(3-methoxyphenyl)ethenyl]-7-methyl-3-[3-(phosphonooxy)propyl-1-(2-propynyl)-1H-purine-2,6-dione disodium salt hydrate), in modulating cocaine- and quinpirole-induced reinstatement to cocaine seeking. Intra-NAc pretreatment of CGS 21680 reduced both cocaine- and quinpirole-induced reinstatement. These effects were specific to cocaine reinstatement as intra-NAc CGS 21680 had no effect on sucrose seeking in rats trained to self-administer sucrose pellets. Intra-NAc treatment with MSX-3 modestly reinstated cocaine seeking when given alone, and exacerbated both cocaine- and quinpirole-induced reinstatement. Interestingly, the exacerbation of cocaine seeking produced by MSX-3 was only observed at sub-threshold doses of cocaine and quinpirole, suggesting that removing tonic A2A receptor activity enables behaviors mediated by dopamine receptors. Taken together, these findings suggest that A2A receptor stimulation reduces, while A2A blockade amplifies, D2 receptor

  11. Adenosine receptors and caffeine in retinopathy of prematurity.

    Science.gov (United States)

    Chen, Jiang-Fan; Zhang, Shuya; Zhou, Rong; Lin, Zhenlang; Cai, Xiaohong; Lin, Jing; Huo, Yuqing; Liu, Xiaoling

    2017-06-01

    Retinopathy of prematurity (ROP) is a major cause of childhood blindness in the world and is caused by oxygen-induced damage to the developing retinal vasculature, resulting in hyperoxia-induced vaso-obliteration and subsequent delayed retinal vascularization and hypoxia-induced pathological neovascularization driven by vascular endothelial growth factor (VEGF) signaling pathway in retina. Current anti-VEGF therapy has shown some effective in a clinical trial, but is associated with the unintended effects on delayed eye growth and retinal vasculature development of preterm infants. Notably, cellular responses to hypoxia are characterized by robust increases in extracellular adenosine production and the markedly induced adenosine receptors, which provide a novel target for preferential control of pathological angiogenesis without affecting normal vascular development. Here, we review the experimental evidence in support of adenosine receptor-based therapeutic strategy for ROP, including the aberrant adenosine signaling in oxygen-induced retinopathy and the role of three adenosine receptor subtypes (A 1 R, A 2A R, A 2B R) in development and treatment of ROP using oxygen-induced retinopathy models. The clinical and initial animal evidence that implicate the therapeutic effect of caffeine (a non-selective adenosine receptor antagonist) in treatment of ROP are highlighted. Lastly, we discussed the translational potential as well therapeutic advantage of adenosine receptor- and caffeine-based therapy for ROR and possibly other proliferative retinopathy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Stability of [5-3H]uridine-5'-triphosphate

    International Nuclear Information System (INIS)

    Brabec, D.

    1980-01-01

    The effect of temperature, the solvent systems, evaporation, volume reduction, etc. on the decomposition rate of [5- 3 H]uridine-5'-triphosphate was investigated. The decomposition rates and optimum storage conditions were established. The possibility of reducing the duration of the purification and separation process was examined. (author)

  13. Application of the newly developed Japanese adenosine normal database for adenosine stress myocardial scintigraphy.

    Science.gov (United States)

    Harata, Shingo; Isobe, Satoshi; Morishima, Itsuro; Suzuki, Susumu; Tsuboi, Hideyuki; Sone, Takahito; Ishii, Hideki; Murohara, Toyoaki

    2015-10-01

    The currently available Japanese normal database (NDB) in stress myocardial perfusion scintigraphy recommended by the Japanese Society of Nuclear Medicine (JSNM-NDB) is created based on the data from exercise tests. The newly developed adenosine normal database (ADS-NDB) remains to be validated for patients undergoing adenosine stress test. We tested whether the diagnostic accuracy of adenosine stress test is improved by the use of ADS-NDB (Kanazawa University). Of 233 consecutive patients undergoing (99m)Tc-MIBI adenosine stress test, 112 patients were tested. The stress/rest myocardial (99m)Tc-MIBI single-photon emission computed tomography (SPECT) images were analyzed by AutoQUANT 7.2 with both ADS-NDB and JSNM-NDB. The summed stress score (SSS) and summed difference score (SDS) were calculated. The agreements of the post-stress defect severity between ADS-NDB and JSNM-NDB were assessed using a weighted kappa statistic. In all patients, mean SSSs of all, right coronary artery (RCA), left anterior descending (LAD), and left circumflex (LCx) territories were significantly lower with ADS-NDB than those with JSNM-NDB. Mean SDSs in all, RCA, and LAD territories were significantly lower with ADS-NDB than those with JSNM-NDB. In 28 patients with significant coronary stenosis, the mean SSS in the RCA territory was significantly lower with ADS-NDB than that with JSNM-NDB. In 84 patients without ischemia, both mean SSSs and SDSs in all, RCA, LAD, and LCx territories were significantly lower with ADS-NDB than those with JSNM-NDB. Weighted kappa values of all patients, patients with significant stenosis, and patients without ischemia were 0.89, 0.83, and 0.92, respectively. Differences were observed between results from ADS-NDB and JSNM-NDB. The diagnostic accuracy of adenosine stress myocardial perfusion scintigraphy may be improved by reducing false-positive results.

  14. Simultaneous (68)Ga-DOTA-TOC PET/MRI with gadoxetate disodium in patients with neuroendocrine tumor.

    Science.gov (United States)

    Hope, Thomas A; Pampaloni, Miguel Hernandez; Nakakura, Eric; VanBrocklin, Henry; Slater, James; Jivan, Salma; Aparici, Carina Mari; Yee, Judy; Bergsland, Emily

    2015-08-01

    To evaluate a simultaneous PET/MRI approach to imaging patients with neuroendocrine tumor using a combination of (68)Ga-DOTA-TOC as a PET contrast agent and gadoxetate disodium as a hepatobiliary MRI contrast agent. Ten patients with neuroendocrine tumor with known or suspected hepatic disease were imaged using a (68)Ga-DOTA-TOC PET/CT immediately followed by a 3.0T time-of-flight PET/MRI, using a combined whole body and liver specific imaging. The presence of lesions and DOTA-TOC avidity were assessed on CT, PET from PET/CT, diffusion weighted imaging, hepatobiliary phase imaging (HBP), and PET from PET/MRI. Maximum standardized uptake values (SUVmax) in hepatic lesions and nodal metastases were compared between PET/CT and PET/MRI, as were detection rates using each imaging approach. A total of 101 hepatic lesions were identified, 47 of which were DOTA-TOC avid and able to be individually measured on both PET/CT and PET/MRI. HBP imaging had a higher sensitivity for detection of hepatic lesions compared to CT or PET (99% vs. 46% and 64%, respectively; p values TOC and gadoxetate disodium was successful in whole body staging of patients with neuroendocrine tumor. HBP imaging had an increased detection rate for hepatic metastases.

  15. Complexing of lanthanides with adenosine-5'-triphosphate

    International Nuclear Information System (INIS)

    Svetlova, I.E.; Smirnova, N.S.; Dobrynina, N.A.; Martynenko, L.I.; Evseev, A.M.

    1988-01-01

    REE complexing with adenozine-5-triphosphoric acid in aqueous solutions at 25 deg C is studied by the method of pH metric titration using mathematical simulation. Ranges of existence are found, the composition is determined, stability constants of complexes of different composition are calculated

  16. Method for extending the useful shelf-life of refrigerated red blood cells by flushing with inert gas

    Science.gov (United States)

    Bitensky, M.W.; Yoshida, Tatsuro

    1997-04-29

    A method is disclosed using oxygen removal for extending the useful shelf-life of refrigerated red blood cells. A cost-effective, 4 C storage procedure that preserves red cell quality and prolongs post-transfusion in vivo survival is described. Preservation of adenosine triphosphate levels and reduction in hemolysis and in membrane vesicle production of red blood cells stored at 4 C for prolonged periods of time is achieved by removing oxygen from the red blood cells at the time of storage; in particular, by flushing with an inert gas. Adenosine triphosphate levels of the stored red blood cells are boosted in some samples by addition of ammonium phosphate. 4 figs.

  17. ANALYSIS OF BETAMETHASONE DISODIUM PHOSPHATE INJECTION AND OPHTHALMIC SOLUTION BY HPLC, KINETIC INTERPRETATION AND DETERMINATION OF SHELF LIFE

    Directory of Open Access Journals (Sweden)

    A. Ghanbarpour

    1994-07-01

    Full Text Available Corticosteroids are widely used in therapeutics in different formulations. Betamethasone disodium phosphate is one of the most soluble of the adrenocorticosteroidal agents. It is therefore very suitable for intravenous use and particularly for ophthalmic formulations."nAcceleration method is used to determine expiration date of aqueous formulations manufactured in Iran.

  18. Comparison of diagnostic value of coronary artery disease between ATP-stress and exercise-stress thallium myocardial SPECT images

    International Nuclear Information System (INIS)

    Suzuki, Shigeo

    1994-01-01

    A study was made between adenosine triphosphate disodium (ATP)-stress thallium myocardial scintigrams and exercise-stress scintigrams to compare their respective extents and degree of defects. The subjects of the study were 33 ischemic heart disease patients, who received ATP stress and treadmill exercise stress with a mean interval of 25 days. ATP was infused for 5 minutes with an infusion rate of 0.16 or 0.18 mg per kg of body weight per minute. Thallium was injected three minutes after infusion. The percent-defect index (percentage of the extent and degree of the defects for all 33 patients), was calculated with visual scoring using a five-zone myocardial division method and semi-quantitative four-grade representation method for both the ATP and exercise SPECT images. The extent of the defects in ATP- and exercise-stress images was 51.5% and 44.2%, and that in redistribution images was 36.4% and 33.9%, respectively. The degree of defects in ATP- and exercise-stress images was 35.8% and 32.3%, while that in redistribution images was 20.8% and 17.2%, respectively (p=NS in all cases). In conclusion, the image quality of thallium SPECT with ATP stress was equivalent that of exercise stress, indicating identical diagnostic values for coronary lesions. (author)

  19. Extracellular adenosine controls NKT-cell-dependent hepatitis induction.

    Science.gov (United States)

    Subramanian, Meenakshi; Kini, Radhika; Madasu, Manasa; Ohta, Akiko; Nowak, Michael; Exley, Mark; Sitkovsky, Michail; Ohta, Akio

    2014-04-01

    Extracellular adenosine regulates inflammatory responses via the A2A adenosine receptor (A2AR). A2AR deficiency results in much exaggerated acute hepatitis, indicating nonredundancy of adenosine-A2AR pathway in inhibiting immune activation. To identify a critical target of immunoregulatory effect of extracellular adenosine, we focused on NKT cells, which play an indispensable role in hepatitis. An A2AR agonist abolished NKT-cell-dependent induction of acute hepatitis by concanavalin A (Con A) or α-galactosylceramide in mice, corresponding to downregulation of activation markers and cytokines in NKT cells and of NK-cell co-activation. These results show that A2AR signaling can downregulate NKT-cell activation and suppress NKT-cell-triggered inflammatory responses. Next, we hypothesized that NKT cells might be under physiological control of the adenosine-A2AR pathway. Indeed, both Con A and α-galactosylceramide induced more severe hepatitis in A2AR-deficient mice than in WT controls. Transfer of A2AR-deficient NKT cells into A2AR-expressing recipients resulted in exaggeration of Con A-induced liver damage, suggesting that NKT-cell activation is controlled by endogenous adenosine via A2AR, and this physiological regulatory mechanism of NKT cells is critical in the control of tissue-damaging inflammation. The current study suggests the possibility to manipulate NKT-cell activity in inflammatory disorders through intervention to the adenosine-A2AR pathway. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Photoreaction of 4,5',8-trimethylpsoralen with adenosine

    International Nuclear Information System (INIS)

    Sangchul Shim; Seungju Choi

    1990-01-01

    The near-UV induced photoreaction of 4,5',8-trimethylpsoralen (TMP) with adenosine was investigated in a dry film state. Four major photoadducts were isolated and purified by reverse-phase liquid chromatography. The structures of the photoproducts were elucidated on the basis of spectroscopic methods, including UV, FT-IR, mass spectrometry (FAB and EI methods) and 1 H-NMR analysis. These photoproducts were characterized to be TMP-adenosine 1:1 adducts, which resulted from the covalent bond formation between the carbon C(4) of TMP and ribose 1' or 5' carbon of adenosine. Of the photoadducts, one photoadduct (V) was the major product, reflecting some selectivity in the photoreaction of TMP with adenosine in the solid state. (author)

  1. Involvement of adenosine in the antiinflammatory action of ketamine.

    Science.gov (United States)

    Mazar, Julia; Rogachev, Boris; Shaked, Gad; Ziv, Nadav Y; Czeiger, David; Chaimovitz, Cidio; Zlotnik, Moshe; Mukmenev, Igor; Byk, Gerardo; Douvdevani, Amos

    2005-06-01

    Ketamine is an anesthetic drug. Subanesthetic doses of ketamine have been shown to reduce interleukin-6 concentrations after surgery and to reduce mortality and the production of tumor necrosis factor alpha and interleukin 6 in septic animals. Similarly, adenosine was shown to reduce tumor necrosis factor alpha and mortality of septic animals. The aim of this study was to determine whether adenosine mediates the antiinflammatory effects of ketamine. Sepsis was induced in mice by lipopolysaccharide or Escherichia coli inoculation. Leukocyte recruitment and cytokine concentrations were used as inflammation markers. Adenosine concentrations were assayed by high-performance liquid chromatography, and the involvement of adenosine in the effects of ketamine was demonstrated by adenosine receptor agonists and antagonists. Ketamine markedly reduced mortality from sepsis, leukocyte recruitment, and tumor necrosis factor-alpha and interleukin-6 concentrations. Ketamine administration in mice and rats was associated with a surge at 20-35 min of adenosine in serum (up to 5 microm) and peritoneal fluid. The adenosine A2A receptor agonist CGS-21680 mimicked the effect of ketamine in peritonitis, whereas the A2A receptor antagonists DMPX and ZM 241385 blocked its antiinflammatory effects. In contrast, A1 and A3 receptor antagonists had no effect. ZM 241385 reversed the beneficial effect of ketamine on survival from bacterial sepsis. The current data suggest that the sepsis-protective antiinflammatory effects of ketamine are mediated by the release of adenosine acting through the A2A receptor.

  2. Labeling of thymine with 99m technetium: a suggestion of a chemical model

    International Nuclear Information System (INIS)

    Gutfilen, Bianca; Silva, Claudia Ribeiro da; Bernardo Filho, Mario; Ribeiro, Barbara Luzia Almeida; Mattos, Maura Ferreira

    1996-01-01

    Successful targeting of diagnose but also to stage cancer. It has been shown that certain tumor cells are permeable to low level of exogenous adenosine-diphosphate and adenosine-triphosphate nucleotides, that are incorporated into intracellular pools. We present the labeling of a nucleotide precursor, a base, thymine technetium-99m ( 99m Tc). (author)

  3. Labeling of thymine with {sup 99m} technetium: a suggestion of a chemical model

    Energy Technology Data Exchange (ETDEWEB)

    Gutfilen, Bianca; Silva, Claudia Ribeiro da; Bernardo Filho, Mario [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Biologia. Dept. de Biofisica e Biometria; Ribeiro, Barbara Luzia Almeida [Instituto Nacional do Cancer, Rio de Janeiro, RJ (Brazil). Centro de Pesquisa Basica; Mattos, Maura Ferreira [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Quimica

    1996-03-01

    Successful targeting of diagnose but also to stage cancer. It has been shown that certain tumor cells are permeable to low level of exogenous adenosine-diphosphate and adenosine-triphosphate nucleotides, that are incorporated into intracellular pools. We present the labeling of a nucleotide precursor, a base, thymine technetium-99m ({sup 99m} Tc). (author)

  4. Detrimental effects of adenosine signaling in sickle cell disease

    Science.gov (United States)

    Zhang, Yujin; Dai, Yingbo; Wen, Jiaming; Zhang, Weiru; Grenz, Almut; Sun, Hong; Tao, Lijian; Lu, Guangxiu; Alexander, Danny C; Milburn, Michael V; Carter-Dawson, Louvenia; Lewis, Dorothy E; Zhang, Wenzheng; Eltzschig, Holger K; Kellems, Rodney E; Blackburn, Michael R; Juneja, Harinder S; Xia, Yang

    2016-01-01

    Hypoxia can act as an initial trigger to induce erythrocyte sickling and eventual end organ damage in sickle cell disease (SCD). Many factors and metabolites are altered in response to hypoxia and may contribute to the pathogenesis of the disease. Using metabolomic profiling, we found that the steady-state concentration of adenosine in the blood was elevated in a transgenic mouse model of SCD. Adenosine concentrations were similarly elevated in the blood of humans with SCD. Increased adenosine levels promoted sickling, hemolysis and damage to multiple tissues in SCD transgenic mice and promoted sickling of human erythrocytes. Using biochemical, genetic and pharmacological approaches, we showed that adenosine A2B receptor (A2BR)-mediated induction of 2,3-diphosphoglycerate, an erythrocyte-specific metabolite that decreases the oxygen binding affinity of hemoglobin, underlies the induction of erythrocyte sickling by excess adenosine both in cultured human red blood cells and in SCD transgenic mice. Thus, excessive adenosine signaling through the A2BR has a pathological role in SCD. These findings may provide new therapeutic possibilities for this disease. PMID:21170046

  5. The alterations in adenosine nucleotides and lactic acid in striated muscles of rats during Rigor mortis following death with drowning or cervical dislocation.

    Science.gov (United States)

    Pençe, Halime Hanim; Pençe, Sadrettin; Kurtul, Naciye; Yilmaz, Necat; Kocoglu, Hasan; Bakan, Ebubekir

    2003-01-01

    In this study, adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP) and lactic acid in the muscles of masseter, triceps, and quadriceps obtained from right and left sides of Spraque-Dawley rats following death were investigated. The samples were taken immediately and 120 minutes after death occurred. The rats were killed either by cervical dislocation or drowning. ATP concentrations in the muscles of masseter, triceps, and quadriceps were lower in samples obtained 120 minutes after death than in those obtained immediately after death. ADP, AMP, and lactic acid concentrations in these muscles were higher in samples obtained 120 minutes after death than those obtained immediately after death. A positive linear correlation was determined between ATP and ADP concentrations in quadriceps muscles of the rats killed with cervical dislocation and in triceps muscles of the rats killed with drowning. When rats killed with cervical dislocation and with drowning were compared, ADP, AMP, and lactic acid concentrations were lower in the former than in the latter for both times (immediately and 120 minutes after death occurred). In the case of drowning, ATP is consumed faster because of hard exercise or severe physical activity, resulting in a faster rigor mortis. Higher lactic acid levels were determined in muscles of the rats killed with drowning than the other group. In the control and electric shock rats, ATP decreased in different levels in the three different muscle types mentioned above in control group, being much decline in masseter and then in quadriceps. This may be caused by lower mass and less glycogen storage of masseter. No different ATP levels were measured in drowning group with respect to the muscle type possibly because of the severe activity of triceps and quadriceps and because of smaller mass of masseter. One can conclude that the occurrence of rigor mortis is closely related to the mode of death.

  6. Elevated placental adenosine signaling contributes to the pathogenesis of preeclampsia.

    Science.gov (United States)

    Iriyama, Takayuki; Sun, Kaiqi; Parchim, Nicholas F; Li, Jessica; Zhao, Cheng; Song, Anren; Hart, Laura A; Blackwell, Sean C; Sibai, Baha M; Chan, Lee-Nien L; Chan, Teh-Sheng; Hicks, M John; Blackburn, Michael R; Kellems, Rodney E; Xia, Yang

    2015-02-24

    Preeclampsia is a prevalent hypertensive disorder of pregnancy and a leading cause of maternal and neonatal morbidity and mortality worldwide. This pathogenic condition is speculated to be caused by placental abnormalities that contribute to the maternal syndrome. However, the specific factors and signaling pathways that lead to impaired placentas and maternal disease development remain elusive. Using 2 independent animal models of preeclampsia (genetically engineered pregnant mice with elevated adenosine exclusively in placentas and a pathogenic autoantibody-induced preeclampsia mouse model), we demonstrated that chronically elevated placental adenosine was sufficient to induce hallmark features of preeclampsia, including hypertension, proteinuria, small fetuses, and impaired placental vasculature. Genetic and pharmacological approaches revealed that elevated placental adenosine coupled with excessive A₂B adenosine receptor (ADORA2B) signaling contributed to the development of these features of preeclampsia. Mechanistically, we provided both human and mouse evidence that elevated placental CD73 is a key enzyme causing increased placental adenosine, thereby contributing to preeclampsia. We determined that elevated placental adenosine signaling is a previously unrecognized pathogenic factor for preeclampsia. Moreover, our findings revealed the molecular basis underlying the elevation of placental adenosine and the detrimental role of excess placental adenosine in the pathophysiology of preeclampsia, and thereby, we highlight novel therapeutic targets. © 2014 American Heart Association, Inc.

  7. Reentry Tachycardia in Children: Adenosine Can Make It Worse.

    Science.gov (United States)

    Hien, Maximilian D; Benito Castro, Fernando; Fournier, Philippe; Filleron, Anne; Tran, Tu-Anh

    2016-10-08

    We report on a rare but severe complication of adenosine use in a child with reentry tachycardia. Treatment with adenosine, which is the standard medical therapy of atrioventricular reentry tachycardia, led to the development of an irregular wide complex tachycardia, caused by rapid ventricular response to atrial fibrillation. The girl was finally stabilized with electrical cardioversion. We analyze the pathomechanism and discuss possible treatment options. Atrial fibrillation, as well as its conduction to the ventricles, can be caused by adenosine. Rapid ventricular response in children with Wolff-Parkinson-White syndrome is more frequent than previously believed. A patient history of atrial fibrillation is a contraindication for cardioversion with adenosine and needs to be assessed in children with reentry tachycardia. High-risk patients may potentially profit from prophylactic comedication with antiarrhythmic agents, such as flecainide, ibutilide, or vernakalant, before adenosine administration.

  8. Insulin and adenosine regulate the phosphatidylcholine concentration in isolated rat adipocyte plasma membranes.

    Science.gov (United States)

    Kiechle, F L; Sykes, E; Artiss, J D

    1995-01-01

    Blockade of adenosine receptors by 3-isobutyl-1-methylxanthine or degradation of endogenous adenosine with adenosine deaminase increased the phosphatidylcholine concentration in isolated rat adipocyte plasma membranes, an effect which was suppressed by the phosphatidylethanolamine methyltransferase inhibitor, S-adenosyl-L-homocysteine, and reversed by the adenosine analogue, N6-(L-phenylisopropyl)-adenosine. For example, the addition of N6-(L-phenylisopropyl)-adenosine to adenosine deaminase pretreated plasma membranes rapidly lowered the concentration of phosphatidylcholine by 171 nmol/mg at 30 seconds compared to control. Insulin-induced stimulation of phospholipid methylation in membranes treated with 3-isobutyl-1-methylxanthine or adenosine deaminase was achieved only after the addition of N6-(L-phenylisopropyl)-adenosine. These results suggest that adenosine receptor occupancy inhibits phospholipid methylation, is required for insulin stimulation of phospholipid methylation, and may perhaps activate a phosphatidylcholine-specific phospholipase C or phospholipase D.

  9. Influence of Proton and Salt Concentration on the Chromonic Liquid Crystal Phase Diagram of Disodium Cromoglycate Solutions: Prospects and Limitations of a Host for DNA Nanostructures.

    Science.gov (United States)

    Zhang, Bingru; Kitzerow, Heinz-S

    2016-03-31

    Lyotropic chromonic liquid crystals have recently been suggested for use as a self-organized host for dispersing and aligning self-organized DNA origami nanostructures. However, an appropriate pH value and a suitable cation concentration are necessary to stabilize such nanostructures and to avoid unfolding of the DNA. The present study shows that the nematic and columnar liquid crystal phases appearing in aqueous solutions of disodium cromoglycate are robust against the replacement of deionized water by a neutral or alkaline buffer solution. However, disodium cromoglycate precipitates when an acidic buffer is used or when the concentration of magnesium cations exceeds a critical concentration of about 0.6-0.7 mmol/L.

  10. Metabolic changes of cultured DRG neurons induced by adenosine using confocal microscopy imaging

    Science.gov (United States)

    Zheng, Liqin; Huang, Yimei; Chen, Jiangxu; Wang, Yuhua; Yang, Hongqin; Zhang, Yanding; Xie, Shusen

    2012-12-01

    Adenosine exerts multiple effects on pain transmission in the peripheral nervous system. This study was performed to use confocal microscopy to evaluate whether adenosine could affect dorsal root ganglia (DRG) neurons in vitro and test which adenosine receptor mediates the effect of adenosine on DRG neurons. After adding adenosine with different concentration, we compared the metabolic changes by the real time imaging of calcium and mitochondria membrane potential using confocal microscopy. The results showed that the effect of 500 μM adenosine on the metabolic changes of DRG neurons was more significant than others. Furthermore, four different adenosine receptor antagonists were used to study which receptor mediated the influences of adenosine on the cultured DRG neurons. All adenosine receptor antagonists especially A1 receptor antagonist (DPCPX) had effect on the Ca2+ and mitochondria membrane potential dynamics of DRG neurons. The above studies demonstrated that the effect of adenosine which may be involved in the signal transmission on the sensory neurons was dose-dependent, and all the four adenosine receptors especially the A1R may mediate the transmission.

  11. The value of gadoxetate disodium-enhanced MR imaging for predicting posthepatectomy liver failure after major hepatic resection: A preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Seung Hyun, E-mail: shcho2405@gmail.com [Department of Radiology, Daegu Fatima Hospital, 576-31 Sinam-dong, Dong-gu, Daegu 701-600 (Korea, Republic of); Kang, Ung Rae, E-mail: tadtail@hanmail.net [Department of Radiology, Catholic University of Daegu, School of Medicine, 3056-6 Daemyung-4-dong, Nam-gu, Daegu 705-718 (Korea, Republic of); Kim, Joo Dong, E-mail: milledr@naver.com [Department of Surgery, Catholic University of Daegu, School of Medicine, 3056-6 Daemyung-4-dong, Nam-gu, Daegu 705-718 (Korea, Republic of); Han, Young Seok, E-mail: gshyskhk@hanmail.net [Department of Surgery, Catholic University of Daegu, School of Medicine, 3056-6 Daemyung-4-dong, Nam-gu, Daegu 705-718 (Korea, Republic of); Choi, Dong Lak, E-mail: dnchoi@cu.ac.kr [Department of Surgery, Catholic University of Daegu, School of Medicine, 3056-6 Daemyung-4-dong, Nam-gu, Daegu 705-718 (Korea, Republic of)

    2011-11-15

    Purpose: To investigate whether preoperative gadoxetate-disodium-enhanced MR imaging predicts posthepatectomy liver failure (PHLF) in patients who underwent major hepatic resection. Materials and methods: Twenty nine patients who underwent preoperative gadoxetate-disodium-enhanced MR imaging and following major hepatic resection were enrolled. Hepatic parenchymal signal intensity (SI) on pre-contrast T1-weighted imaging and 20 min hepatocyte phase was measured at each of the four liver segments by two observers using region of interest measurements. The mean value was calculated and used at each phase. The relative contrast enhancement index (RCEI) was calculated: (20 min hepatocyte phase SI - pre-contrast SI)/pre-contrast SI. PHLF was determined by the International Study Group of Liver Surgery 2011 guidelines. Correlation analysis was performed between preoperative liver function test and RCEI. Diagnostic accuracy of RCEI for predicting PHLF was calculated with receiver operating characteristic curve analysis. The reproducibility of the RCEI measurement was evaluated. Results: There was a significant correlation between preoperative albumin (r = 0.496, P = 0.006), T-bilirubin (r = -0.383, P = 0.041), and RCEI. Seven patients (24%) experienced PHLF, and one of these patients (3%) died. The diagnostic accuracy of RCEI was 0.838 (sensitivity 85.7%, specificity 77.3%, cut-off value: 0.7508, 95% confidence interval: 0.654, 0.947). The 95% limits of agreement and ICC between repeated RCEI measurements were 18.4% of the mean and 0.94, respectively, and between RCEI measurements by the two observers were 21.7% and 0.929, respectively. Conclusion: Our results show that preoperative gadoxetate-disodium-enhanced MR imaging can predict PHLF in patients who underwent major hepatic resection.

  12. Ethanol-induced increase in portal blood glow: Role of adenosine

    International Nuclear Information System (INIS)

    Orrego, H.; Carmichael, F.J.; Saldivia, V.; Giles, H.G.; Sandrin, S.; Israel, Y.

    1988-01-01

    The mechanism by which ethanol induces an increase in portal vein blood flow was studied in rats using radiolabeled microspheres. Ethanol by gavage resulted in an increase of 50-70% in portal vein blood flow. The ethanol-induced increase in portal blood flow was suppressed by the adenosine receptor blocker 8-phenyltheophylline. By itself, 8-phenyltheophylline was without effect on cardiac output or portal blood flow. Adenosine infusion resulted in a dose-dependent increase in portal blood flow. This adenosine-induced increase in portal blood flow was inhibited by 8-phenyltheophylline in a dose-dependent manner. Both alcohol and adenosine significantly reduced preportal vascular resistance by 40% and 60%, respectively. These effects were fully suppressed by 8-phenyltheophylline. It is concluded that adenosine is a likely candidate to mediate the ethanol-induced increase in portal vein blood flow. It is suggested that an increase in circulating acetate and liver hypoxia may mediate the effects of alcohol by increasing tissue and interstitial adenosine levels

  13. Adenosine signaling promotes regeneration of pancreatic β-cells in vivo

    Science.gov (United States)

    Andersson, Olov; Adams, Bruce A.; Yoo, Daniel; Ellis, Gregory C.; Gut, Philipp; Anderson, Ryan M.; German, Michael S.; Stainier, Didier Y. R.

    2012-01-01

    Diabetes can be controlled with insulin injections, but a curative approach that restores the number of insulin-producing β-cells is still needed. Using a zebrafish model of diabetes, we screened ~7000 small molecules to identify enhancers of β-cell regeneration. The compounds we identified converge on the adenosine signaling pathway and include exogenous agonists and compounds that inhibit degradation of endogenously produced adenosine. The most potent enhancer of β-cell regeneration was the adenosine agonist 5′-N-Ethylcarboxamidoadenosine (NECA), which acting through the adenosine receptor A2aa increased β-cell proliferation and accelerated restoration of normoglycemia in zebrafish. Despite markedly stimulating β-cell proliferation during regeneration, NECA had only a modest effect during development. The proliferative and glucose-lowering effect of NECA was confirmed in diabetic mice, suggesting an evolutionarily conserved role for adenosine in β-cell regeneration. With this whole-organism screen, we identified components of the adenosine pathway that could be therapeutically targeted for the treatment of diabetes. PMID:22608007

  14. A rapid enzymatic assay for high-throughput screening of adenosine-producing strains

    Science.gov (United States)

    Dong, Huina; Zu, Xin; Zheng, Ping; Zhang, Dawei

    2015-01-01

    Adenosine is a major local regulator of tissue function and industrially useful as precursor for the production of medicinal nucleoside substances. High-throughput screening of adenosine overproducers is important for industrial microorganism breeding. An enzymatic assay of adenosine was developed by combined adenosine deaminase (ADA) with indophenol method. The ADA catalyzes the cleavage of adenosine to inosine and NH3, the latter can be accurately determined by indophenol method. The assay system was optimized to deliver a good performance and could tolerate the addition of inorganic salts and many nutrition components to the assay mixtures. Adenosine could be accurately determined by this assay using 96-well microplates. Spike and recovery tests showed that this assay can accurately and reproducibly determine increases in adenosine in fermentation broth without any pretreatment to remove proteins and potentially interfering low-molecular-weight molecules. This assay was also applied to high-throughput screening for high adenosine-producing strains. The high selectivity and accuracy of the ADA assay provides rapid and high-throughput analysis of adenosine in large numbers of samples. PMID:25580842

  15. Regioselective 1-N-Alkylation and Rearrangement of Adenosine Derivatives.

    Science.gov (United States)

    Oslovsky, Vladimir E; Drenichev, Mikhail S; Mikhailov, Sergey N

    2015-01-01

    Several methods for the preparation of some N(6)-substituted adenosines based on selective 1-N-alkylation with subsequent Dimroth rearrangement were developed. The proposed methods seem to be effective for the preparation of natural N(6)-isopentenyl- and N(6)-benzyladenosines, which are known to possess pronounced biological activities. Direct 1-N-alkylation of 2',3',5'-tri-O-acetyladenosine and 3',5'-di-O-acetyl-2'-deoxyadenosine with alkyl halides in N,N-dimethylformamide (DMF) in the presence of BaCO3 and KI gave 1-N-substituted derivatives with quantitative yields, whereas 1-N-alkylation of adenosine was accompanied by significant O-alkylation. Moreover, the reaction of trimethylsilyl derivatives of N(6)-acetyl-2',3',5'-tri-O-acetyladenosine and N(6)-acetyl-3',5'-di-O-acetyl-2'-deoxyadenosine with alkyl halides leads to the formation of the stable 1-N-substituted adenosines. Dimroth rearrangement of 1-N-substituted adenosines in aqueous ammonia yields pure N(6)-substituted adenosines.

  16. Adenosine induced ventricular arrhythmias in the emergency room

    NARCIS (Netherlands)

    Tan, H. L.; Spekhorst, H. H.; Peters, R. J.; Wilde, A. A.

    2001-01-01

    While adenosine effectively terminates most supraventricular tachycardias (SVT), rare case reports have demonstrated its proarrhythmic potential, including induction of ventricular tachycardia (VT). The aim of this study was to define the proarrhythmic effects of adenosine in a large, unselected

  17. TOR induced resistance to toxic adenosine analogs in Leishmania brought about by the internalization and degradation of the adenosine permease

    Science.gov (United States)

    Detke, Siegfried

    2007-01-01

    TOR is an atypical multidrug resistance protein present in the human protozoan parasite, Leishmania. Resistance to the toxic adenosine analog tubercidin was brought about by redirecting the adenosine permease from the plasma membrane to the multivesicular tubule lysosome. The cells became resistant to tubercidin because they were unable to take up and accumulate this toxic purine. The domain which was recognized by TOR in this internalization pathway was identified by expressing portions of this transporter in Leishmania and assessing whether they were capable of hindering the multidrug resistance capability of TOR. This approach identified the adenosine permease region spanning Met289 to Trp305. This region was also the epitope recognized by the internalization mechanism. An internal deletion mutant lacking Met289-Trp305 was functionally active but could no longer be internalized in cells with high TOR levels. The internalization and altered trafficking of the adenosine permease by TOR was observed in yeast and human embryonic kidney cells co-expressing these two Leishmania proteins indicating that the internalization process was conserved in evolutionary diverse organisms. The inability of Saccharomyces with a temperature sensitive ubiquitin ligase to internalize adenosine permease suggested that ubiquitination was involved in this altered trafficking. PMID:17428463

  18. Mechanism of A2 adenosine receptor activation. I. Blockade of A2 adenosine receptors by photoaffinity labeling

    International Nuclear Information System (INIS)

    Lohse, M.J.; Klotz, K.N.; Schwabe, U.

    1991-01-01

    It has previously been shown that covalent incorporation of the photoreactive adenosine derivative (R)-2-azido-N6-p-hydroxy-phenylisopropyladenosine [(R)-AHPIA] into the A1 adenosine receptor of intact fat cells leads to a persistent activation of this receptor, resulting in a reduction of cellular cAMP levels. In contrast, covalent incorporation of (R)-AHPIA into human platelet membranes, which contain only stimulatory A2 adenosine receptors, reduces adenylate cyclase stimulation via these receptors. This effect of (R)-AHPIA is specific for the A2 receptor and can be prevented by the adenosine receptor antagonist theophylline. Binding studies indicate that up to 90% of A2 receptors can be blocked by photoincorporation of (R)-AHPIA. However, the remaining 10-20% of A2 receptors are sufficient to mediate an adenylate cyclase stimulation of up to 50% of the control value. Similarly, the activation via these 10-20% of receptors occurs with a half-life that is only 2 times longer than that in control membranes. This indicates the presence of a receptor reserve, with respect to both the extent and the rate of adenylate cyclase stimulation. These observations require a modification of the models of receptor-adenylate cyclase coupling

  19. Molecular vibration-activity relationship in the agonism of adenosine receptors.

    Science.gov (United States)

    Chee, Hyun Keun; Oh, S June

    2013-12-01

    The molecular vibration-activity relationship in the receptor-ligand interaction of adenosine receptors was investigated by structure similarity, molecular vibration, and hierarchical clustering in a dataset of 46 ligands of adenosine receptors. The resulting dendrogram was compared with those of another kind of fingerprint or descriptor. The dendrogram result produced by corralled intensity of molecular vibrational frequency outperformed four other analyses in the current study of adenosine receptor agonism and antagonism. The tree that was produced by clustering analysis of molecular vibration patterns showed its potential for the functional classification of adenosine receptor ligands.

  20. Model Linking Plasma and Intracellular Tenofovir/Emtricitabine with Deoxynucleoside Triphosphates.

    Directory of Open Access Journals (Sweden)

    Xinhui Chen

    Full Text Available The coformulation of the nucleos(tide analogs (NA tenofovir (TFV disoproxil fumarate (TDF and emtricitabine (FTC is approved for HIV-infection treatment and prevention. Plasma TFV and FTC undergo complicated hybrid processes to form, accumulate, and retain as their active intracellular anabolites: TFV-diphosphate (TFV-DP and FTC-triphosphate (FTC-TP. Such complexities manifest in nonlinear intracellular pharmacokinetics (PK. In target cells, TFV-DP/FTC-TP compete with endogenous deoxynucleoside triphosphates (dNTP at the active site of HIV reverse transcriptase, underscoring the importance of analog:dNTP ratios for antiviral efficacy. However, NA such as TFV and FTC have the potential to disturb the dNTP pool, which could augment or reduce their efficacies. We conducted a pharmacokinetics-pharmacodynamics (PKPD study among forty subjects receiving daily TDF/FTC (300 mg/200 mg from the first-dose to pharmacological intracellular steady-state (30 days. TFV/FTC in plasma, TFV-DP/FTC-TP and dNTPs in peripheral blood mononuclear cells (PBMC were quantified using validated LC/MS/MS methodologies. Concentration-time data were analyzed using nonlinear mixed effects modeling (NONMEM. Formations and the accumulation of intracellular TFV-DP/FTC-TP was driven by plasma TFV/FTC, which was described by a hybrid of first-order formation and saturation. An indirect response link model described the interplay between TFV-DP/FTC-TP and the dNTP pool change. The EC50 (interindividual variability, (%CV of TFV-DP and FTC-TP on the inhibition of deoxyadenosine triphosphate (dATP and deoxycytidine triphosphate (dCTP production were 1020 fmol/106 cells (130% and 44.4 pmol/106 cells (82.5%, resulting in (90% prediction interval 11% (0.45%, 53% and 14% (2.6%, 35% reductions. Model simulations of analog:dNTP molar ratios using IPERGAY dosing suggested that FTC significantly contributes to the protective effect of preexposure prophylaxis (PrEP. Simulation

  1. Studies on the control of development: isolation of Bacillus subtilis mutants blocked early in sporulation and defective in synthesis of highly phosphorylated nucleotides.

    Science.gov (United States)

    Rhaese, H J; Hoch, J A; Groscurth, R

    1977-03-01

    To test our model on the mechanism of initiation of differentiation in Bacillus subtilis, we tested early blocked (stage 0) sporulation mutants for their ability to synthesize highly phosphorylated nucleotides. We also isolated early blocked asporogenous mutants with the aid of the intercalating drug tilorone. Among all mutants tested we found that the spo0F-bearing strain was unable to synthesize adenosine 3'(2')-triphosphate 5'-triphosphate, pppAppp. A revertant of this mutant regained the ability to both sporulate and synthesize pppAppp. Ribosomes of the asporogenous mutant isolated at T2 (2 hr after the end of logarithmic growth) of sporulation, in contrast to the wild type, do not synthesize adenosine 3'(2')-diphosphate 5'-diphosphate, ppApp, or adenosine 3'(2')-diphosphate 5'-triphosphate, pppApp, but synthesize guanosine 3'(2')-diphosphate 5'-diphosphate, ppGpp, and guanosine 3'(2')-diphosphate 5'-triphosphate, pppGpp. This behavior is characteristic of ribosomes from vegetative, not sporulating, cells. Ribosomes from the sporogenous revertant behave like those of the wild type. The results suggest that the spo0F mutation may be a mutation in the structural gene for pppAppp synthetase. The inability to synthesize pppAppp in this strain also prevents the formation of "sporulation-specific ribosomes," i.e., ribosomes that synthetize ppApp and pppApp. The present experiments suggest that the nucleotide pppAppp participates in the initiation of sporulation by triggering a sequencies of events required for the production of heat-resistant spores.

  2. Molecular Vibration-Activity Relationship in the Agonism of Adenosine Receptors

    Directory of Open Access Journals (Sweden)

    Hyun Keun Chee

    2013-12-01

    Full Text Available The molecular vibration-activity relationship in the receptor-ligand interaction of adenosine receptors was investigated by structure similarity, molecular vibration, and hierarchical clustering in a dataset of 46 ligands of adenosine receptors. The resulting dendrogram was compared with those of another kind of fingerprint or descriptor. The dendrogram result produced by corralled intensity of molecular vibrational frequency outperformed four other analyses in the current study of adenosine receptor agonism and antagonism. The tree that was produced by clustering analysis of molecular vibration patterns showed its potential for the functional classification of adenosine receptor ligands.

  3. Adenosine for postoperative analgesia: A systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Xin Jin

    Full Text Available Perioperative infusion of adenosine has been suggested to reduce the requirement for inhalation anesthetics, without causing serious adverse effects in humans. We conducted a meta-analysis of randomized controlled trials evaluating the effect of adenosine on postoperative analgesia.We retrieved articles in computerized searches of Scopus, Web of Science, PubMed, EMBASE, and Cochrane Library databases, up to July 2016. We used adenosine, postoperative analgesia, and postoperative pain(s as key words, with humans, RCT, and CCT as filters. Data of eligible studies were extracted, which included pain scores, cumulative opioid consumption, adverse reactions, and vital signs. Overall incidence rates, relative risk (RR, and 95% confidence intervals (CI were calculated employing fixed-effects or random-effects models, depending on the heterogeneity of the included trials.In total, 757 patients from 9 studies were included. The overall effect of adenosine on postoperative VAS/VRS scores and postoperative opioid consumption was not significantly different from that of controls (P >0.1. The occurrence of PONV and pruritus was not statistically significantly different between an adenosine and nonremifentanil subgroup (P >0.1, but the rate of PONV occurrence was greater in the remifentanil subgroup (P 0.1.Adenosine has no analgesic effect or prophylactic effect against PONV, but reduce systolic blood pressure and heart rates. Adenosine may benefit patients with hypertension, ischemic heart disease, and tachyarrhythmia, thereby improving cardiac function.

  4. Skeletal muscle expresses the extracellular cyclic AMP–adenosine pathway

    Science.gov (United States)

    Chiavegatti, T; Costa, V L; Araújo, M S; Godinho, R O

    2007-01-01

    Background and purpose: cAMP is a key intracellular signalling molecule that regulates multiple processes of the vertebrate skeletal muscle. We have shown that cAMP can be actively pumped out from the skeletal muscle cell. Since in other tissues, cAMP efflux had been associated with extracellular generation of adenosine, in the present study we have assessed the fate of interstitial cAMP and the existence of an extracellular cAMP-adenosine signalling pathway in skeletal muscle. Experimental approach: cAMP efflux and/or its extracellular degradation were analysed by incubating rat cultured skeletal muscle with exogenous cAMP, forskolin or isoprenaline. cAMP and its metabolites were quantified by radioassay or HPLC, respectively. Key results: Incubation of cells with exogenous cAMP was followed by interstitial accumulation of 5′-AMP and adenosine, a phenomenon inhibited by selective inhibitors of ecto-phosphodiesterase (DPSPX) and ecto-nucleotidase (AMPCP). Activation of adenylyl cyclase (AC) in cultured cells with forskolin or isoprenaline increased cAMP efflux and extracellular generation of 5′-AMP and adenosine. Extracellular cAMP-adenosine pathway was also observed after direct and receptor-dependent stimulation of AC in rat extensor muscle ex vivo. These events were attenuated by probenecid, an inhibitor of ATP binding cassette family transporters. Conclusions and implications: Our results show the existence of an extracellular biochemical cascade that converts cAMP into adenosine. The functional relevance of this extracellular signalling system may involve a feedback modulation of cellular response initiated by several G protein-coupled receptor ligands, amplifying cAMP influence to a paracrine mode, through its metabolite, adenosine. PMID:18157164

  5. Primary adenosine monophosphate (AMP) deaminase deficiency in a hypotonic infant.

    Science.gov (United States)

    Castro-Gago, Manuel; Gómez-Lado, Carmen; Pérez-Gay, Laura; Eirís-Puñal, Jesús; Martínez, Elena Pintos; García-Consuegra, Inés; Martín, Miguel Angel

    2011-06-01

    The spectrum of the adenosine monophosphate (AMP) deaminase deficiency ranges from asymptomatic carriers to patients who manifest exercise-induced muscle pain, occasionally rhabdomyolysis, and idiopathic hyperCKemia. However, previous to the introduction of molecular techniques, rare cases with congenital weakness and hypotonia have also been reported. We report a 6-month-old girl with the association of congenital muscle weakness and hypotonia, muscle deficiency of adenosine monophosphate deaminase, and the homozygous C to T mutation at nucleotide 34 of the adenosine monophosphate deaminase-1 gene. This observation indicates the possible existence of a primary adenosine monophosphate deaminase deficiency manifested by congenital muscle weakness and hypotonia.

  6. Molecular Vibration-Activity Relationship in the Agonism of Adenosine Receptors

    OpenAIRE

    Chee, Hyun Keun; Oh, S. June

    2013-01-01

    The molecular vibration-activity relationship in the receptor-ligand interaction of adenosine receptors was investigated by structure similarity, molecular vibration, and hierarchical clustering in a dataset of 46 ligands of adenosine receptors. The resulting dendrogram was compared with those of another kind of fingerprint or descriptor. The dendrogram result produced by corralled intensity of molecular vibrational frequency outperformed four other analyses in the current study of adenosine ...

  7. Adenylate kinase 1 knockout mice have normal thiamine triphosphate levels.

    NARCIS (Netherlands)

    Makarchikov, A.F.; Wins, P.; Janssen, E.E.W.; Wieringa, B.; Grisar, T.; Bettendorff, L.

    2002-01-01

    Thiamine triphosphate (ThTP) is found at low concentrations in most animal tissues and it may act as a phosphate donor for the phosphorylation of proteins, suggesting a potential role in cell signaling. Two mechanisms have been proposed for the enzymatic synthesis of ThTP. A thiamine diphosphate

  8. 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?.

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

    International Nuclear Information System (INIS)

    Andersson, Olov

    2014-01-01

    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?

  10. Activation of Adenylyl Cyclase Causes Stimulation of Adenosine Receptors

    Directory of Open Access Journals (Sweden)

    Thomas Pleli

    2018-03-01

    Full Text Available Background/Aims: Signaling of Gs protein-coupled receptors (GsPCRs is accomplished by stimulation of adenylyl cyclase, causing an increase of the intracellular cAMP concentration, activation of the intracellular cAMP effectors protein kinase A (PKA and Epac, and an efflux of cAMP, the function of which is still unclear. Methods: Activation of adenylyl cyclase by GsPCR agonists or cholera toxin was monitored by measurement of the intracellular cAMP concentration by ELISA, anti-phospho-PKA substrate motif phosphorylation by immunoblotting, and an Epac-FRET assay in the presence and absence of adenosine receptor antagonists or ecto-nucleotide phosphodiesterase/pyrophosphatase2 (eNPP2 inhibitors. The production of AMP from cAMP by recombinant eNPP2 was measured by HPLC. Extracellular adenosine was determined by LC-MS/MS, extracellular ATP by luciferase and LC-MS/MS. The expression of eNPP isoenzymes 1-3 was examined by RT-PCR. The expression of multidrug resistance protein 4 was suppressed by siRNA. Results: Here we show that the activation of GsPCRs and the GsPCRs-independent activation of Gs proteins and adenylyl cyclase by cholera toxin induce stimulation of cell surface adenosine receptors (A2A or A2B adenosine receptors. In PC12 cells stimulation of adenylyl cyclase by GsPCR or cholera toxin caused activation of A2A adenosine receptors by an autocrine signaling pathway involving cAMP efflux through multidrug resistance protein 4 and hydrolysis of released cAMP to AMP by eNPP2. In contrast, in PC3 cells cholera toxin- and GsPCR-induced stimulation of adenylyl cyclase resulted in the activation of A2B adenosine receptors. Conclusion: Our findings show that stimulation of adenylyl cyclase causes a remarkable activation of cell surface adenosine receptors.

  11. Integrated approach to characterize fouling on a flat sheet membrane gravity driven submerged membrane bioreactor

    KAUST Repository

    Fortunato, Luca; Jeong, Sanghyun; Wang, Yiran; Behzad, Ali Reza; Leiknes, TorOve

    2016-01-01

    of different analytical tools, including optical coherence tomography (OCT), liquid chromatography with organic carbon detection (LC-OCD), total organic carbon (TOC), flow cytometer (FCM), adenosine triphosphate analysis (ATP) and scanning electron microscopy

  12. Treatment of out-of-hospital supraventricular tachycardia: adenosine vs verapamil.

    Science.gov (United States)

    Brady, W J; DeBehnke, D J; Wickman, L L; Lindbeck, G

    1996-06-01

    To compare the use of adenosine and the use of verapamil as out-of-hospital therapy for supraventricular tachycardia (SVT). A period of prospective adenosine use (March 1993 to February 1994) was compared with a historical control period of verapamil use (March 1990 to February 1991) for SVT. Data were obtained for SVT patients treated in a metropolitan, fire-department-based paramedic system serving a population of approximately 1 million persons. Standard drug protocols were used and patient outcomes (i.e., conversion rates, complications, and recurrences) were monitored. During the adenosine treatment period, 105 patients had SVT; 87 (83%) received adenosine, of whom 60 (69%) converted to a sinus rhythm (SR). Vagal maneuvers (VM) resulted in restoration of SR in 8 patients (7.6%). Some patients received adenosine for non-SVT rhythms: 7 sinus tachycardia, 18 atrial fibrilation, 7 wide-complex tachycardia (WCT), and 2 ventricular tachycardia; no non-SVT rhythm converted to SR and none of these patients experienced an adverse effect. Twenty-five patients were hemodynamically unstable (systolic blood pressure fibrillation). Recurrence of SVT was noted in 2 adenosine patients and 2 verapamil patients in the out-of-hospital setting and in 23 adenosine patients and 15 verapamil patients after ED arrival, necessitating additional therapy (p = 0.48 and 0.88, for recurrence rates and types of additional therapies, respectively). Hospital diagnoses, outcomes, and ED dispositions were similar for the 2 groups. Adenosine and verapamil were equally successful in converting out-of-hospital SVT in patients with similar etiologies responsible for the SVT. Recurrence of SVT occurred at similar rates for the 2 medications. Rhythm misidentification remains a common issue in out-of-hospital cardiac care in this emergency medical services system.

  13. Regulation of adenosine deaminase (ADA) on induced mouse experimental autoimmune uveitis (EAU) ?

    OpenAIRE

    Liang, Dongchun; Zuo, Aijun; Zhao, Ronglan; Shao, Hui; Kaplan, Henry J.; Sun, Deming

    2016-01-01

    Adenosine is an important regulator of the immune response and adenosine deaminase (ADA) inhibits this regulatory effect by converting adenosine into functionally inactive molecules. Studies have shown that adenosine receptor (AR) agonists can be either anti- or pro-inflammatory. Clarification of the mechanisms that cause these opposing effects should provide a better guide for therapeutic intervention. In this study, we investigated the effect of ADA on the development of experimental autoim...

  14. Adenosine receptor modulation of seizure susceptibility in rats

    International Nuclear Information System (INIS)

    Szot, P.

    1987-01-01

    Adenosine is considered to be a neuromodulator or cotransmitter in the periphery and CNS. This neuromodulatory action of adenosine may be observed as an anticonvulsant effect. Dose-response curves for R-phenylisopropyladenosine (PIA), cycohexyladenosine (CHA), 2-chloroadenosine (2-ClAdo), N-ethylcarboxamidoadenosine (NECA) and S-PIA were generated against PTZ seizure thresholds in the rat. The rank order of potency for adenosine agonists to elevate PTZ seizure threshold was R-PIA > 2-ClAdo > NECA > CHA > S-PIA. R-PIA was approximately 80-fold more potent than S-PIA. This 80-fold difference in potency between the diasteriomers of PIA was consistent with an A 1 adenoise receptor-mediated response. The anticonvulsant action of 2-ClAdo was reversed by pretreatment with theoplylline. Chronic administration of theophylline significantly increased the specific binding of 3 H-cyclohexyladenosine in membranes of the cerebral cortex and cerebellum of the rat. Chronic exposure to theophylline produced a significant increase in the densities of both the high- and low-affinity forms of A 1 adenosine receptors in the cerebral cortex

  15. Safety of adenosine in stress cerebral perfusion imaging

    International Nuclear Information System (INIS)

    Hu Pengcheng; Gu Yushen; Liu Wenguan; Xiu Yan; Zhu Weimin; Chen Shuguang; Shi Hongcheng

    2009-01-01

    Objective: To evaluate the safety of adenosine as pharmacological stress agents in stress cerebral perfusion imaging. Methods: Eighty patients under investigation for suspected cerebral vessel disease were recruited. Each had a resting scan and a stress scan on different days. The adenosine stress protocol was as same as the protocol used in adenosine stress myocardial perfusion imaging. Subjective and objective side-effects were investigated during pharmacological stress procedure. Results: All patients completed the 6 min infusion protocol without premature termination on safety criteria or due to intolerable symptoms. 46 patients had mild side effects. 20 patients (25%) had dizziness, 12 patients (15%) had palpitation, 1 patient (1%) was hypotensive, 7 patients (9%) had dyspnoea, 4 patients (5%) felt hot, 3 patients (4%) had sweat, 4 patients (5%) had nausea, 6 patients (8%) had flushing, 19 patients (24%) had chest pain, 6 patients (8%) had abdomen pain, 3 patients (4%) had abnormal taste and 1 patient (1%) were thirsty. Transient ST change occurred in only 1 patient. Conclusion: Adenosine stress cerebral perfusion imaging is a safe diagnostic method with mild side effects. (authors)

  16. The Adverse Events and Hemodynamic Effects of Adenosine-Based Cardiac MRI

    International Nuclear Information System (INIS)

    Voigtlander, Thomas; Magedanz, Annett; Schmermund, Axel; Bramlage, Peter; Elsaesser, Amelie; Kauczor, Hans-Ulrich; Mohrs, Oliver K.

    2011-01-01

    We wanted to prospectively assess the adverse events and hemodynamic effects associated with an intravenous adenosine infusion in patients with suspected or known coronary artery disease and who were undergoing cardiac MRI. One hundred and sixty-eight patients (64 ± 9 years) received adenosine (140 μg/kg/min) during cardiac MRI. Before and during the administration, the heart rate, systemic blood pressure, and oxygen saturation were monitored using a MRI-compatible system. We documented any signs and symptoms of potential adverse events. In total, 47 out of 168 patients (28%) experienced adverse effects, which were mostly mild or moderate. In 13 patients (8%), the adenosine infusion was discontinued due to intolerable dyspnea or chest pain. No high grade atrioventricular block, bronchospasm or other life-threatening adverse events occurred. The hemodynamic measurements showed a significant increase in the heart rate during adenosine infusion (69.3 ± 11.7 versus 82.4 ± 13.0 beats/min, respectively; p < 0.001). A significant but clinically irrelevant increase in oxygen saturation occurred during adenosine infusion (96 ± 1.9% versus 97 ± 1.3%, respectively; p < 0.001). The blood pressure did not significantly change during adenosine infusion (systolic: 142.8 ± 24.0 versus 140.9 ± 25.7 mmHg; diastolic: 80.2 ± 12.5 mmHg versus 78.9 ± 15.6, respectively). This study confirms the safety of adenosine infusion during cardiac MRI. A considerable proportion of all patients will experience minor adverse effects and some patients will not tolerate adenosine infusion. However, all adverse events can be successfully managed by a radiologist. The increased heart rate during adenosine infusion highlights the need to individually adjust the settings according to the patient, e.g., the number of slices of myocardial perfusion imaging.

  17. Role of Adenosine Receptor A2A in Traumatic Optic Neuropathies (Addendum)

    Science.gov (United States)

    2016-03-01

    diabetic retinopathy . Life Sci. 2013 Jul 30;93(2-3):78-88. doi: 10.1016/j.lfs.2013.05.024. Epub 2013 Jun 12.PMID:23770229 7 AIMS: This study was...undertaken to determine the effect of an adenosine kinase inhibitor (AKI) in diabetic retinopathy (DR). We have shown previously that adenosine signaling...reported recently that adenosine kinase upregulated in retinal tissue of diabetic retinopathy (Elsherbiny et al., 2013). Adenosine kinase (ADK) converts

  18. Long-term performance and fouling analysis of full-scale direct nanofiltration (NF) installations treating anoxic groundwater

    KAUST Repository

    Beyer, Florian; Rietman, Bas M.; Zwijnenburg, Arie; Van Den Brink, Paula J.; Vrouwenvelder, Johannes S.; Jarzembowska, Monika; Laurinonyte, Judita; Stams, Alfons JM M; Plugge, Caroline M.

    2014-01-01

    . Investigations using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), total organic carbon (TOC) and adenosine triphosphate (ATP) measurements revealed a complex mixture of organic, biological and inorganic materials. The fouling

  19. BCX4430 - A broad-spectrum antiviral adenosine nucleoside analog under development for the treatment of Ebola virus disease.

    Science.gov (United States)

    Taylor, Raymond; Kotian, Pravin; Warren, Travis; Panchal, Rekha; Bavari, Sina; Julander, Justin; Dobo, Sylvia; Rose, Angela; El-Kattan, Yahya; Taubenheim, Brian; Babu, Yarlagadda; Sheridan, William P

    2016-01-01

    The adenosine nucleoside analog BCX4430 is a direct-acting antiviral drug under investigation for the treatment of serious and life-threatening infections from highly pathogenic viruses, such as the Ebola virus. Cellular kinases phosphorylate BCX4430 to a triphosphate that mimics ATP; viral RNA polymerases incorporate the drug's monophosphate nucleotide into the growing RNA chain, causing premature chain termination. BCX4430 is active in vitro against many RNA viral pathogens, including the filoviruses and emerging infectious agents such as MERS-CoV and SARS-CoV. In vivo, BCX4430 is active after intramuscular, intraperitoneal, and oral administration in a variety of experimental infections. In nonclinical studies involving lethal infections with Ebola virus, Marburg virus, Rift Valley fever virus, and Yellow Fever virus, BCX4430 has demonstrated pronounced efficacy. In experiments conducted in several models, both a reduction in the viral load and an improvement in survival were found to be related to the dose of BCX4430. A Phase 1 clinical trial of intramuscular administration of BCX4430 in healthy subjects is currently ongoing. Copyright © 2016 King Saud Bin Abdulaziz University for Health Sciences. All rights reserved.

  20. Molecular Evidence of Adenosine Deaminase Linking Adenosine A2A Receptor and CD26 Proteins.

    Science.gov (United States)

    Moreno, Estefanía; Canet, Júlia; Gracia, Eduard; Lluís, Carme; Mallol, Josefa; Canela, Enric I; Cortés, Antoni; Casadó, Vicent

    2018-01-01

    Adenosine is an endogenous purine nucleoside that acts in all living systems as a homeostatic network regulator through many pathways, which are adenosine receptor (AR)-dependent and -independent. From a metabolic point of view, adenosine deaminase (ADA) is an essential protein in the regulation of the total intracellular and extracellular adenosine in a tissue. In addition to its cytosolic localization, ADA is also expressed as an ecto-enzyme on the surface of different cells. Dipeptidyl peptidase IV (CD26) and some ARs act as binding proteins for extracellular ADA in humans. Since CD26 and ARs interact with ADA at opposite sites, we have investigated if ADA can function as a cell-to-cell communication molecule by bridging the anchoring molecules CD26 and A 2A R present on the surfaces of the interacting cells. By combining site-directed mutagenesis of ADA amino acids involved in binding to A 2A R and a modification of the bioluminescence resonance energy transfer (BRET) technique that allows detection of interactions between two proteins expressed in different cell populations with low steric hindrance (NanoBRET), we show direct evidence of the specific formation of trimeric complexes CD26-ADA-A 2A R involving two cells. By dynamic mass redistribution assays and ligand binding experiments, we also demonstrate that A 2A R-NanoLuc fusion proteins are functional. The existence of this ternary complex is in good agreement with the hypothesis that ADA could bridge T-cells (expressing CD26) and dendritic cells (expressing A 2A R). This is a new metabolic function for ecto-ADA that, being a single chain protein, it has been considered as an example of moonlighting protein, because it performs more than one functional role (as a catalyst, a costimulator, an allosteric modulator and a cell-to-cell connector) without partitioning these functions in different subunits.

  1. Molecular Evidence of Adenosine Deaminase Linking Adenosine A2A Receptor and CD26 Proteins

    Directory of Open Access Journals (Sweden)

    Estefanía Moreno

    2018-02-01

    Full Text Available Adenosine is an endogenous purine nucleoside that acts in all living systems as a homeostatic network regulator through many pathways, which are adenosine receptor (AR-dependent and -independent. From a metabolic point of view, adenosine deaminase (ADA is an essential protein in the regulation of the total intracellular and extracellular adenosine in a tissue. In addition to its cytosolic localization, ADA is also expressed as an ecto-enzyme on the surface of different cells. Dipeptidyl peptidase IV (CD26 and some ARs act as binding proteins for extracellular ADA in humans. Since CD26 and ARs interact with ADA at opposite sites, we have investigated if ADA can function as a cell-to-cell communication molecule by bridging the anchoring molecules CD26 and A2AR present on the surfaces of the interacting cells. By combining site-directed mutagenesis of ADA amino acids involved in binding to A2AR and a modification of the bioluminescence resonance energy transfer (BRET technique that allows detection of interactions between two proteins expressed in different cell populations with low steric hindrance (NanoBRET, we show direct evidence of the specific formation of trimeric complexes CD26-ADA-A2AR involving two cells. By dynamic mass redistribution assays and ligand binding experiments, we also demonstrate that A2AR-NanoLuc fusion proteins are functional. The existence of this ternary complex is in good agreement with the hypothesis that ADA could bridge T-cells (expressing CD26 and dendritic cells (expressing A2AR. This is a new metabolic function for ecto-ADA that, being a single chain protein, it has been considered as an example of moonlighting protein, because it performs more than one functional role (as a catalyst, a costimulator, an allosteric modulator and a cell-to-cell connector without partitioning these functions in different subunits.

  2. Erythrocytic Adenosine Monophosphate as an Alternative Purine Source in Plasmodium falciparum*

    Science.gov (United States)

    Cassera, María B.; Hazleton, Keith Z.; Riegelhaupt, Paul M.; Merino, Emilio F.; Luo, Minkui; Akabas, Myles H.; Schramm, Vern L.

    2008-01-01

    Plasmodium falciparum is a purine auxotroph, salvaging purines from erythrocytes for synthesis of RNA and DNA. Hypoxanthine is the key precursor for purine metabolism in Plasmodium. Inhibition of hypoxanthine-forming reactions in both erythrocytes and parasites is lethal to cultured P. falciparum. We observed that high concentrations of adenosine can rescue cultured parasites from purine nucleoside phosphorylase and adenosine deaminase blockade but not when erythrocyte adenosine kinase is also inhibited. P. falciparum lacks adenosine kinase but can salvage AMP synthesized in the erythrocyte cytoplasm to provide purines when both human and Plasmodium purine nucleoside phosphorylases and adenosine deaminases are inhibited. Transport studies in Xenopus laevis oocytes expressing the P. falciparum nucleoside transporter PfNT1 established that this transporter does not transport AMP. These metabolic patterns establish the existence of a novel nucleoside monophosphate transport pathway in P. falciparum. PMID:18799466

  3. Purification and properties of adenosine kinase from rat brain.

    Science.gov (United States)

    Yamada, Y; Goto, H; Ogasawara, N

    1980-12-04

    Adenosine kinase (ATP:adenosine 5'-phosphotransferase, EC 2.7.1.20) has been purified to apparent homogeneity from rat brain by (NH4)2SO4 fractionation, affinity chromatography on AMP-Sepharose 4B, gel filtration with Sephadex G-100, and DE-52 cellulose column chromatography. The yield was 56% of the initial activity with a final specific activity of 7.8 mumol/min per mg protein. The molecular weight was estimated as 38 000 by gel filtration with Sephadex G-100 and 41 000 by acrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS). The enzyme catalyzed the phosphorylation of adenosine, deoxyadenosine, arabinoadenosine, inosine and ribavirin. The activity of deoxyadenosine phosphorylation was 20% that of adenosine phosphorylation. The pH optimum profile was biphasic; a sharp pH optimum at pH 5.5 and a broad pH optimum at pH 7.5-8.5. The Km value for adenosine was 0.2 microM and the maximum activity was observed at 0.5 microM. At higher concentrations of adenosine, the activity was strongly inhibited. The Km value for ATP was 0.02 mM and that for Mg2+ was 0.1 mM. GTP, dGTP, dATP and UTP were also proved to be effective phosphate donors. Co2+ was as effective as Mg2+, and Ca2+, Mn2+ or Ni2+ showed about 50% of the activity for Mg2+. The kinase is quite unstable, but stable in the presence of a high concentration of salt; e.g., 0.15 M KCl.

  4. Physical mechanisms of biological molecular motors

    International Nuclear Information System (INIS)

    Miller, John H. Jr.; Vajrala, Vijayanand; Infante, Hans L.; Claycomb, James R.; Palanisami, Akilan; Fang Jie; Mercier, George T.

    2009-01-01

    Biological motors generally fall into two categories: (1) those that convert chemical into mechanical energy via hydrolysis of a nucleoside triphosphate, usually adenosine triphosphate, regarded as life's chemical currency of energy and (2) membrane bound motors driven directly by an ion gradient and/or membrane potential. Here we argue that electrostatic interactions play a vital role for both types of motors and, therefore, the tools of physics can greatly contribute to understanding biological motors

  5. O-alkylation of disodium salt of diethyl 3,4-dihydroxythiophene-2,5-dicarboxylate with 1,2-dichloroethane catalyzed by ionic type phase transfer catalyst and potassium iodide

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Huasheng; Yin, Hengbo; Wang, Aili; Shen, Jun; Yan, Xiaobo; Liu, Yumin; Zhang, Changhua [Jiangsu University, Zhenjiang (China)

    2014-01-15

    Diethyl 3,4-ethylenedioxy thiophene-2,5-dicarboxylate was efficiently synthesized via the O-alkylation of disodium salt of diethyl 3,4-dihydroxy thiophene-2,5-dicarboxylate with 1,2-dichloroethane over ionic type phase transfer catalysts, such as tetrabutyl ammonium bromide and benzyl triethyl ammonium chloride. The ionic type phase transfer catalysts showed higher catalytic activities than the nonionic type phase transfer catalysts, such as triethylamine, pyridine, 18-crown-6, and polyethylene glycol 400/600, in the O-alkylation reaction. The conversion of the disodium salt of more than 97% and the selectivity of diethyl 3,4-ethylenedioxy thiophene-2,5-dicarboxylate of more than 98% were achieved when the O-alkylation reaction was synergistically catalyzed by tetrabutyl ammonium bromide and potassium iodide.

  6. Cyclic adenosine 3:5-monophosphate binding proteins in Hartmannella culbertsoni

    International Nuclear Information System (INIS)

    Verma, A.K.; Krishna Murti, C.R.

    1976-01-01

    When 100, 000 g supernatant fractions of homogenates of Hartmannella culbertsoni were incubated with ('- 3 H)-cyclic adenosine 3 : 5 monophosphate and passed through a sephadex G-100 column, radioactivity appeared with protein fractions eluted after the void colume. About 75% radioactivity bound to these fractions was recovered as cyclic adenosine 3 : 5 monophosphate. Unlabelled cAMP diluted the amount of radioactivity bound. Adenosine, deoxyadenosine, 5-AMP, 3-AMP, ADP and ATP did not inhibit binding. (author)

  7. You Are What You Eat

    Science.gov (United States)

    ... by generating adenosine triphosphate, or ATP, the main currency of metabolism. In addition to providing and storing ... wafer-like chips similar in size to those used in computers. Amino acids link head-to-tail ...

  8. Dietary strategies to treat hyperhomocysteinaemia based on the ...

    African Journals Online (AJOL)

    2014-01-13

    Jan 13, 2014 ... of a methyl group and the purine base, adenine (from adenosine triphosphate or ..... rat liver betaine‑homocysteine methyltransferase gene expression and organization of the .... Betaine rescue of an animal model with.

  9. Evidence for evoked release of adenosine and glutamate from cultured cerebellar granule cells

    International Nuclear Information System (INIS)

    Schousboe, A.; Frandsen, A.; Drejer, J.

    1989-01-01

    Evoked release of [ 3 H]-D-aspartate which labels the neurotransmitter glutamate pool in cultured cerebellar granule cells was compared with evoked release of adenosine from similar cultures. It was found that both adenosine and [3H]-D-aspartate could be released from the neurons in a calcium dependent manner after depolarization of the cells with either 10-100 microM glutamate or 50 mM KCl. Cultures of cerebellar granule cells treated with 50 microM kainate to eliminate GABAergic neurons behaved in the same way. This together with the observation that cultured astrocytes did not exhibit a calcium dependent, potassium stimulated adenosine release strongly suggest that cerebellar granule cells release adenosine in a neurotransmitter-like fashion together with glutamate which is the classical neurotransmitter of these neurons. Studies of the metabolism of adenosine showed that in the granule cells adenosine is rapidly metabolized to ATP, ADP, and AMP, but in spite of this, adenosine was found to be released preferential to ATP

  10. Freeze-Dried Human Red Blood Cells

    Science.gov (United States)

    1992-04-15

    period in the liquid state. 2. The levels of glycolytic intermediates (ATP, adenosine 5’triphosphate; 2,3-DPG 2, 3- diphosphoglycerate ) in rehydrated...8217 diphosphate, ADP; adenosine 5 monophosphate, AMP; 2,3- diphosphoglycerate . 2.3-DPG and lactate: (2) measurement of cell indices (mean cell volume (MCV), mean...monophosphate: 2,3-DPG. 2.3- diphosphoglycerate : MCV. Mean Cell Volume: MCH, Mean Cell Hemoglobin: MCHC, Mean Cell Hemoglobin Concentrations. ** Lactate levels

  11. 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

    hamster or rat. However, the role of adenosine in human BAT is unknown. Here we show that adenosine activates human and murine brown adipocytes at low nanomolar concentrations. Adenosine is released in BAT during stimulation of sympathetic nerves as well as from brown adipocytes. The adenosine A2A...

  12. [Effects of pamidronate disodium (Bonin) combined with chemotherapy on bone pain in multiple myeloma].

    Science.gov (United States)

    Leng, Yun; Chen, Shi-lun; Shi, Hong-zhi

    2002-10-01

    Objective. To evaluate the therapeutic effects of Disodium Pamidronate (Bonin) on bone pain in multiple myeloma. Method. 18 patients received only chemotherapy and 16 patients with addition of Bonin were compared. Result. The bone pain was significantly relieved both in chemotherapy alone group and in the combination group of Bonin with chemotherapy after treatment (P<0.01, as compared with before therapy). However, the effects of combination group were more dramatical than that of the other group (P<0.05). No obvious side-effects were observed except mild fever in one patient in the combination group. Conclusion. Bonin, as a safe and effective Bisphosphonates preparation, could relieve bone pain in multiple myeloma more effectively when combined with chemotherapy.

  13. Astrocyte-derived adenosine is central to the hypnogenic effect of glucose

    Science.gov (United States)

    Scharbarg, Emeric; Daenens, Marion; Lemaître, Frédéric; Geoffroy, Hélène; Guille-Collignon, Manon; Gallopin, Thierry; Rancillac, Armelle

    2016-01-01

    Sleep has been hypothesised to maintain a close relationship with metabolism. Here we focus on the brain structure that triggers slow-wave sleep, the ventrolateral preoptic nucleus (VLPO), to explore the cellular and molecular signalling pathways recruited by an increase in glucose concentration. We used infrared videomicroscopy on ex vivo brain slices to establish that glucose induces vasodilations specifically in the VLPO via the astrocytic release of adenosine. Real-time detection by in situ purine biosensors further revealed that the adenosine level doubles in response to glucose, and triples during the wakefulness period. Finally, patch-clamp recordings uncovered the depolarizing effect of adenosine and its A2A receptor agonist, CGS-21680, on sleep-promoting VLPO neurons. Altogether, our results provide new insights into the metabolically driven release of adenosine. We hypothesise that adenosine adjusts the local energy supply to local neuronal activity in response to glucose. This pathway could contribute to sleep-wake transition and sleep intensity. PMID:26755200

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

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yimin; Long, Mary C.; Ranganathan, Senthil; Escuyer, Vincent; Parker, William B.; Li, Rongbao, E-mail: li@sri.org [Southern Research Institute, 2000 Ninth Avenue South, Birmingham, Alabama 35205 (United States)

    2005-06-01

    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 P3{sub 1}21, 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.

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

    International Nuclear Information System (INIS)

    Wang, Yimin; Long, Mary C.; Ranganathan, Senthil; Escuyer, Vincent; Parker, William B.; Li, Rongbao

    2005-01-01

    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 P3 1 21, 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

  16. Traditional Acupuncture Triggers a Local Increase in Adenosine in Human Subjects

    OpenAIRE

    Takano, Takahiro; Chen, Xiaolin; Luo, Fang; Fujita, Takumi; Ren, Zeguang; Goldman, Nanna; Zhao, Yuanli; Markman, John D.; Nedergaard, Maiken

    2012-01-01

    Acupuncture is a form of Eastern medicine that has been practiced for centuries. Despite its long history and worldwide application, the biological mechanisms of acupuncture in relieving pain have been poorly defined. Recent studies in mice, however, demonstrate that acupuncture triggers increases in interstitial adenosine, which reduces the severity of chronic pain through adenosine A1 receptors, suggesting that adenosine-mediated antinociception contributes to the clinical benefits of acupu...

  17. 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

    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.......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...

  18. Oral tremor induced by the muscarinic agonist pilocarpine is suppressed by the adenosine A2A antagonists MSX-3 and SCH58261, but not the adenosine A1 antagonist DPCPX.

    Science.gov (United States)

    Collins, Lyndsey E; Galtieri, Daniel J; Brennum, Lise T; Sager, Thomas N; Hockemeyer, Jörg; Müller, Christa E; Hinman, James R; Chrobak, James J; Salamone, John D

    2010-02-01

    Tremulous jaw movements in rats, which can be induced by dopamine (DA) antagonists, DA depletion, and cholinomimetics, have served as a useful model for studies of tremor. Although adenosine A(2A) antagonists can reduce the tremulous jaw movements induced by DA antagonists and DA depletion, there are conflicting reports about the interaction between adenosine antagonists and cholinomimetic drugs. The present studies investigated the ability of adenosine antagonists to reverse the tremorogenic effect of the muscarinic agonist pilocarpine. While the adenosine A(2A) antagonist MSX-3 was incapable of reversing the tremulous jaw movements induced by the 4.0mg/kg dose of pilocarpine, both MSX-3 and the adenosine A(2A) antagonist SCH58261 reversed the tremulous jaw movements elicited by 0.5mg/kg pilocarpine. Systemic administration of the adenosine A(1) antagonist DPCPX failed to reverse the tremulous jaw movements induced by either an acute 0.5mg/kg dose of the cholinomimetic pilocarpine or the DA D2 antagonist pimozide, indicating that the tremorolytic effects of adenosine antagonists may be receptor subtype specific. Behaviorally active doses of MSX-3 and SCH 58261 showed substantial in vivo occupancy of A(2A) receptors, but DPCPX did not. The results of these studies support the use of adenosine A(2A) antagonists for the treatment of tremor. Copyright 2009 Elsevier Inc. All rights reserved.

  19. Physical mechanisms of biological molecular motors

    Energy Technology Data Exchange (ETDEWEB)

    Miller, John H. Jr. [Department of Physics and Texas Center for Superconductivity, University of Houston, 4800 Calhoun Road, Ste. 617 SR1 Houston, TX 77204-5005 (United States)], E-mail: jhmiller@uh.edu; Vajrala, Vijayanand; Infante, Hans L. [Department of Physics and Texas Center for Superconductivity, University of Houston, 4800 Calhoun Road, Ste. 617 SR1 Houston, TX 77204-5005 (United States); Claycomb, James R. [Department of Physics and Texas Center for Superconductivity, University of Houston, 4800 Calhoun Road, Ste. 617 SR1 Houston, TX 77204-5005 (United States); Department of Mathematics and Physics, Houston Baptist University, 7502 Fondren Road, Houston, TX 77074-3298 (United States); Palanisami, Akilan; Fang Jie; Mercier, George T. [Department of Physics and Texas Center for Superconductivity, University of Houston, 4800 Calhoun Road, Ste. 617 SR1 Houston, TX 77204-5005 (United States)

    2009-03-01

    Biological motors generally fall into two categories: (1) those that convert chemical into mechanical energy via hydrolysis of a nucleoside triphosphate, usually adenosine triphosphate, regarded as life's chemical currency of energy and (2) membrane bound motors driven directly by an ion gradient and/or membrane potential. Here we argue that electrostatic interactions play a vital role for both types of motors and, therefore, the tools of physics can greatly contribute to understanding biological motors.

  20. Effects of ketamine and its isomers on ischemic preconditioning in the isolated rat heart

    NARCIS (Netherlands)

    Molojavyi, A.; Preckel, B.; Comfère, T.; Müllenheim, J.; Thämer, V.; Schlack, W.

    2001-01-01

    BACKGROUND: Ischemic preconditioning protects the heart against subsequent ischemia. Opening of the adenosine triphosphate-sensitive potassium (KATP) channel is a key mechanism of preconditioning. Ketamine blocks KATP channels of isolated cardiomyocytes. The authors investigated the effects of

  1. Creatine kinase activity is associated with blood pressure

    NARCIS (Netherlands)

    Brewster, Lizzy M.; Mairuhu, Gideon; Bindraban, Navin R.; Koopmans, Richard P.; Clark, Joseph F.; van Montfrans, Gert A.

    2006-01-01

    BACKGROUND: We previously hypothesized that high activity of creatine kinase, the central regulatory enzyme of energy metabolism, facilitates the development of high blood pressure. Creatine kinase rapidly provides adenosine triphosphate to highly energy-demanding processes, including cardiovascular

  2. Elevated Adenosine Induces Placental DNA Hypomethylation Independent of A2B Receptor Signaling in Preeclampsia.

    Science.gov (United States)

    Huang, Aji; Wu, Hongyu; Iriyama, Takayuki; Zhang, Yujin; Sun, Kaiqi; Song, Anren; Liu, Hong; Peng, Zhangzhe; Tang, Lili; Lee, Minjung; Huang, Yun; Ni, Xin; Kellems, Rodney E; Xia, Yang

    2017-07-01

    Preeclampsia is a prevalent pregnancy hypertensive disease with both maternal and fetal morbidity and mortality. Emerging evidence indicates that global placental DNA hypomethylation is observed in patients with preeclampsia and is linked to altered gene expression and disease development. However, the molecular basis underlying placental epigenetic changes in preeclampsia remains unclear. Using 2 independent experimental models of preeclampsia, adenosine deaminase-deficient mice and a pathogenic autoantibody-induced mouse model of preeclampsia, we demonstrate that elevated placental adenosine not only induces hallmark features of preeclampsia but also causes placental DNA hypomethylation. The use of genetic approaches to express an adenosine deaminase minigene specifically in placentas, or adenosine deaminase enzyme replacement therapy, restored placental adenosine to normal levels, attenuated preeclampsia features, and abolished placental DNA hypomethylation in adenosine deaminase-deficient mice. Genetic deletion of CD73 (an ectonucleotidase that converts AMP to adenosine) prevented the elevation of placental adenosine in the autoantibody-induced preeclampsia mouse model and ameliorated preeclampsia features and placental DNA hypomethylation. Immunohistochemical studies revealed that elevated placental adenosine-mediated DNA hypomethylation predominantly occurs in spongiotrophoblasts and labyrinthine trophoblasts and that this effect is independent of A2B adenosine receptor activation in both preeclampsia models. Extending our mouse findings to humans, we used cultured human trophoblasts to demonstrate that adenosine functions intracellularly and induces DNA hypomethylation without A2B adenosine receptor activation. Altogether, both mouse and human studies reveal novel mechanisms underlying placental DNA hypomethylation and potential therapeutic approaches for preeclampsia. © 2017 American Heart Association, Inc.

  3. Using optical tweezers to relate the chemical and mechanical cross-bridge cycles.

    OpenAIRE

    Steffen, Walter; Sleep, John

    2004-01-01

    In most current models of muscle contraction there are two translational steps, the working stroke, whereby an attached myosin cross-bridge moves relative to the actin filament, and the repriming step, in which the cross-bridge returns to its original orientation. The development of single molecule methods has allowed a more detailed investigation of the relationship of these mechanical steps to the underlying biochemistry. In the normal adenosine triphosphate cycle, myosin.adenosine diphosph...

  4. Ecto-5′-Nucleotidase: A Candidate Virulence Factor in Streptococcus sanguinis Experimental Endocarditis

    OpenAIRE

    Fan, Jingyuan; Zhang, Yongshu; Chuang-Smith, Olivia N.; Frank, Kristi L.; Guenther, Brian D.; Kern, Marissa; Schlievert, Patrick M.; Herzberg, Mark C.

    2012-01-01

    Streptococcus sanguinis is the most common cause of infective endocarditis (IE). Since the molecular basis of virulence of this oral commensal bacterium remains unclear, we searched the genome of S. sanguinis for previously unidentified virulence factors. We identified a cell surface ecto-5′-nucleotidase (Nt5e), as a candidate virulence factor. By colorimetric phosphate assay, we showed that S. sanguinis Nt5e can hydrolyze extracellular adenosine triphosphate to generate adenosine. Moreover, ...

  5. Synthesis of carbon-11 labelled cyclopentyltheophylline: A radioligand for PET studies of adenosine receptors

    International Nuclear Information System (INIS)

    Yorke, J.C.; Prenant, C.; Crouzel, C.

    1990-01-01

    Adenosine is presently considered as a neuromodulator, and an adenosine system has been described including secretory neurons, with a diffused distribution, specific receptors and a re-uptake system distributed heterogeneously in different anatomic areas. In order to localize the adenosine receptors in vivo by PET, the authors have synthesized the carbon-11 labelled 8-cyclopentyltheophylline, a known adenosine antagonist of A 1 receptors

  6. 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

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

    International Nuclear Information System (INIS)

    Bajaj, Mamta; Moriyama, Hideaki

    2007-01-01

    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 1 2 1 2 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 M of 1.8 Å 3 Da −1

  8. Red blood cell phosphate concentration and osmotic resistance during dietary phosphate depletion in dairy cows

    NARCIS (Netherlands)

    Grünberg, W; Mol, J A; Teske, E

    BACKGROUND: Hypophosphatemia in early lactating dairy cows has been implicated as primary cause for postparturient hemoglobinuria in cattle. Decreased availability of phosphorus has been proposed to reduce adenosine triphosphate synthesis of erythrocytes and thereby reduce osmotic resistance of

  9. Rapid detection of E. Coli O157:H7 by IFAST and ATP bioluminescence assay for water analysis

    CSIR Research Space (South Africa)

    Ngamsom, B

    2016-10-01

    Full Text Available The present investigation reports isolation and detection of E. coli O157:H7 employing a simple and portable microfluidic device based on immiscible filtration assisted by surface tension (IFAST) and adenosine triphosphate (ATP) bioluminescence...

  10. Structure of the orthorhombic form of human inosine triphosphate pyrophosphatase

    International Nuclear Information System (INIS)

    Porta, Jason; Kolar, Carol; Kozmin, Stanislav G.; Pavlov, Youri I.; Borgstahl, Gloria E. O.

    2006-01-01

    X-ray crystallographic analysis of human inosine triphosphate pyrophosphohydrolase provided the secondary structure and active-site structure at 1.6 Å resolution in an orthorhombic crystal form. The structure gives a framework for future structure–function studies employing site-directed mutagenesis and for the identification of substrate/product-binding sites. The structure of human inosine triphosphate pyrophosphohydrolase (ITPA) has been determined using diffraction data to 1.6 Å resolution. ITPA contributes to the accurate replication of DNA by cleansing cellular dNTP pools of mutagenic nucleotide purine analogs such as dITP or dXTP. A similar high-resolution unpublished structure has been deposited in the Protein Data Bank from a monoclinic and pseudo-merohedrally twinned crystal. Here, cocrystallization of ITPA with a molar ratio of XTP appears to have improved the crystals by eliminating twinning and resulted in an orthorhombic space group. However, there was no evidence for bound XTP in the structure. Comparison with substrate-bound NTPase from a thermophilic organism predicts the movement of residues within helix α1, the loop before α6 and helix α7 to cap off the active site when substrate is bound

  11. Squalenoyl adenosine nanoparticles provide neuroprotection after stroke and spinal cord injury

    Science.gov (United States)

    Gaudin, Alice; Yemisci, Müge; Eroglu, Hakan; Lepetre-Mouelhi, Sinda; Turkoglu, Omer Faruk; Dönmez-Demir, Buket; Caban, Seçil; Sargon, Mustafa Fevzi; Garcia-Argote, Sébastien; Pieters, Grégory; Loreau, Olivier; Rousseau, Bernard; Tagit, Oya; Hildebrandt, Niko; Le Dantec, Yannick; Mougin, Julie; Valetti, Sabrina; Chacun, Hélène; Nicolas, Valérie; Desmaële, Didier; Andrieux, Karine; Capan, Yilmaz; Dalkara, Turgay; Couvreur, Patrick

    2014-12-01

    There is an urgent need to develop new therapeutic approaches for the treatment of severe neurological trauma, such as stroke and spinal cord injuries. However, many drugs with potential neuropharmacological activity, such as adenosine, are inefficient upon systemic administration because of their fast metabolization and rapid clearance from the bloodstream. Here, we show that conjugation of adenosine to the lipid squalene and the subsequent formation of nanoassemblies allows prolonged circulation of this nucleoside, providing neuroprotection in mouse stroke and rat spinal cord injury models. The animals receiving systemic administration of squalenoyl adenosine nanoassemblies showed a significant improvement of their neurologic deficit score in the case of cerebral ischaemia, and an early motor recovery of the hindlimbs in the case of spinal cord injury. Moreover, in vitro and in vivo studies demonstrated that the nanoassemblies were able to extend adenosine circulation and its interaction with the neurovascular unit. This Article shows, for the first time, that a hydrophilic and rapidly metabolized molecule such as adenosine may become pharmacologically efficient owing to a single conjugation with the lipid squalene.

  12. Deprotonated imidodiphosphate in AMPPNP-containing protein structures

    International Nuclear Information System (INIS)

    Dauter, Miroslawa; Dauter, Zbigniew

    2011-01-01

    In certain AMPPNP-containing protein structures, the nitrogen bridging the two terminal phosphate groups can be deprotonated. Many different proteins utilize the chemical energy provided by the cofactor adenosine triphosphate (ATP) for their proper function. A number of structures in the Protein Data Bank (PDB) contain adenosine 5′-(β,γ-imido)triphosphate (AMPPNP), a nonhydrolysable analog of ATP in which the bridging O atom between the two terminal phosphate groups is substituted by the imido function. Under mild conditions imides do not have acidic properties and thus the imide nitrogen should be protonated. However, an analysis of protein structures containing AMPPNP reveals that the imide group is deprotonated in certain complexes if the negative charges of the phosphate moieties in AMPPNP are in part neutralized by coordinating divalent metals or a guanidinium group of an arginine

  13. 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.

  14. 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

    ) 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......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...

  15. Effects of high doses of intracoronary adenosine on the assessment of fractional flow reserve

    Directory of Open Access Journals (Sweden)

    Ahmed Khashaba

    2014-03-01

    Conclusions: Intracoronary adenosine, at doses higher than currently suggested, lows obtaining FFR values similar to IV adenosine. Intravenous adenosine, which remains the gold standard, might thus be reserved for those lesions with equivocal FFR values.

  16. Radio-chromatographic determination of plasmatic adenosine deaminase (A.D.)

    International Nuclear Information System (INIS)

    Chivot, J.J.; Depernet, D.; Caen, J.

    1970-01-01

    We were able, by using a radio-chromatographic method, to measure an adenosine deaminase activity in normal human heparinized platelet-poor plasma, which can degrade 0.016 μM adenosine. This activity suppressed by heating 56 C for 30 minutes is inhibited by high concentrations of urea and is proportional to the amount of plasma, source of enzyme, in the systems. (authors) [fr

  17. The diagnostic value of immunohistochemically detected methylthioadenosine phosphorylase deficiency in malignant pleural mesotheliomas

    DEFF Research Database (Denmark)

    Zimling, Zarah Glad; Jørgensen, Anne; Santoni-Rugiu, Eric

    2012-01-01

      Malignant pleural mesothelioma (MPM) often causes diagnostic difficulties for pathologists. We assessed whether loss of methylthioadenosine phosphorylase (MTAP), a key enzyme in the intracellular recycling of adenosine triphosphate (ATP) often deleted in MPM, could be detected with immunohistoc...

  18. Hypoxia-induced tumor cell resistance is overcome by synergistic GAPDH-siRNA and chemotherapy co-delivered by long-circulating and cationic-interior liposomes

    NARCIS (Netherlands)

    Guan, J.; Sun, J.; Sun, F.; Lou, B.; Zhang, D.; Mashayekhi, V.; Sadeghi, N.; Storm, G.; Mastrobattista, E.; He, Z.

    2017-01-01

    Chemotherapeutic drug resistance of tumor cells under hypoxic conditions is caused by the inhibition of apoptosis by autophagy and drug efflux via adenosine triphosphate (ATP)-dependent transporter activation, among other factors. Here, we demonstrate that disrupting glyceraldehyde-3-phosphate

  19. Homogeneous electrochemical aptamer-based ATP assay with signal amplification by exonuclease III assisted target recycling.

    Science.gov (United States)

    Liu, Shufeng; Wang, Ying; Zhang, Chengxin; Lin, Ying; Li, Feng

    2013-03-21

    A novel and homogeneous electrochemical aptamer-based adenosine triphosphate (ATP) assay was demonstrated with signal amplification by exonuclease III-assisted target recycling. A superior detection limit of 1 nM toward ATP with an excellent selectivity could be achieved.

  20. A case of severe methylenetetrahydrofolate reductase deficiency presenting as neonatal encephalopathy, seizures, microcephaly and central hypoventilation

    NARCIS (Netherlands)

    Balasubramaniam, S.; Salomons, G.S.; Blom, H.J.

    2013-01-01

    Methylenetetrahydrofolate reductase (MTHFR) is a key regulatory enzyme in the remethylation of homocysteine to methionine. S-adenosylmethionine, formed from methionine and adenosine triphosphate, is the methyl donor in crucial reactions for brain development and function. MTHFR deficiency is the

  1. Nonequilibrium structure and dynamics in a microscopic model of thin-film active gels

    NARCIS (Netherlands)

    Head, D.A.; Briels, Willem J.; Gompper, G.

    2014-01-01

    In the presence of adenosine triphosphate, molecular motors generate active force dipoles that drive suspensions of protein filaments far from thermodynamic equilibrium, leading to exotic dynamics and pattern formation. Microscopic modeling can help to quantify the relationship between individual

  2. Amyotrophic Lateral Sclerosis (ALS and Adenosine Receptors

    Directory of Open Access Journals (Sweden)

    Ana M. Sebastião

    2018-04-01

    Full Text Available In the present review we discuss the potential involvement of adenosinergic signaling, in particular the role of adenosine receptors, in amyotrophic lateral sclerosis (ALS. Though the literature on this topic is not abundant, the information so far available on adenosine receptors in animal models of ALS highlights the interest to continue to explore the role of these receptors in this neurodegenerative disease. Indeed, all motor neurons affected in ALS are responsive to adenosine receptor ligands but interestingly, there are alterations in pre-symptomatic or early symptomatic stages that mirror those in advanced disease stages. Information starts to emerge pointing toward a beneficial role of A2A receptors (A2AR, most probably at early disease states, and a detrimental role of caffeine, in clear contrast with what occurs in other neurodegenerative diseases. However, some evidence also exists on a beneficial action of A2AR antagonists. It may happen that there are time windows where A2AR prove beneficial and others where their blockade is required. Furthermore, the same changes may not occur simultaneously at the different synapses. In line with this, it is not fully understood if ALS is a dying back disease or if it propagates in a centrifugal way. It thus seems crucial to understand how motor neuron dysfunction occurs, how adenosine receptors are involved in those dysfunctions and whether the early changes in purinergic signaling are compensatory or triggers for the disease. Getting this information is crucial before starting the design of purinergic based strategies to halt or delay disease progression.

  3. Fractional Flow Reserve: Intracoronary versus intravenous adenosine induced maximal coronary hyperemia

    Directory of Open Access Journals (Sweden)

    P.S. Sandhu

    2013-03-01

    Conclusions: This study suggests that IC adenosine is equivalent to IV infusion for the determination of FFR. The administration of IC adenosine is easy to use, cost effective, safe and associated with fewer systemic events.

  4. Presynaptic inhibition of GABAergic synaptic transmission by adenosine in mouse hypothalamic hypocretin neurons.

    Science.gov (United States)

    Xia, J X; Xiong, J X; Wang, H K; Duan, S M; Ye, J N; Hu, Z A

    2012-01-10

    Hypocretin neurons in the lateral hypothalamus, a new wakefulness-promoting center, have been recently regarded as an important target involved in endogenous adenosine-regulating sleep homeostasis. The GABAergic synaptic transmissions are the main inhibitory afferents to hypocretin neurons, which play an important role in the regulation of excitability of these neurons. The inhibitory effect of adenosine, a homeostatic sleep-promoting factor, on the excitatory glutamatergic synaptic transmissions in hypocretin neurons has been well documented, whether adenosine also modulates these inhibitory GABAergic synaptic transmissions in these neurons has not been investigated. In this study, the effect of adenosine on inhibitory postsynaptic currents (IPSCs) in hypocretin neurons was examined by using perforated patch-clamp recordings in the acute hypothalamic slices. The findings demonstrated that adenosine suppressed the amplitude of evoked IPSCs in a dose-dependent manner, which was completely abolished by 8-cyclopentyltheophylline (CPT), a selective antagonist of adenosine A1 receptor but not adenosine A2 receptor antagonist 3,7-dimethyl-1-(2-propynyl) xanthine. A presynaptic origin was suggested as following: adenosine increased paired-pulse ratio as well as reduced GABAergic miniature IPSC frequency without affecting the miniature IPSC amplitude. Further findings demonstrated that when the frequency of electrical stimulation was raised to 10 Hz, but not 1 Hz, a time-dependent depression of evoked IPSC amplitude was detected in hypocretin neurons, which could be partially blocked by CPT. However, under a higher frequency at 100 Hz stimulation, CPT had no action on the depressed GABAergic synaptic transmission induced by such tetanic stimulation in these hypocretin neurons. These results suggest that endogenous adenosine generated under certain stronger activities of synaptic transmissions exerts an inhibitory effect on GABAergic synaptic transmission in hypocretin

  5. The advantage of channeling nucleotides for very processive functions [version 2; referees: 3 approved

    Directory of Open Access Journals (Sweden)

    Diana Zala

    2017-07-01

    Full Text Available Nucleoside triphosphate (NTPs, like ATP (adenosine 5’-triphosphate and GTP (guanosine 5’-triphosphate, have long been considered sufficiently concentrated and diffusible to fuel all cellular ATPases (adenosine triphosphatases and GTPases (guanosine triphosphatases in an energetically healthy cell without becoming limiting for function. However, increasing evidence for the importance of local ATP and GTP pools, synthesised in close proximity to ATP- or GTP-consuming reactions, has fundamentally challenged our view of energy metabolism. It has become evident that cellular energy metabolism occurs in many specialised ‘microcompartments’, where energy in the form of NTPs is transferred preferentially from NTP-generating modules directly to NTP-consuming modules. Such energy channeling occurs when diffusion through the cytosol is limited, where these modules are physically close and, in particular, if the NTP-consuming reaction has a very high turnover, i.e. is very processive. Here, we summarise the evidence for these conclusions and describe new insights into the physiological importance and molecular mechanisms of energy channeling gained from recent studies. In particular, we describe the role of glycolytic enzymes for axonal vesicle transport and nucleoside diphosphate kinases for the functions of dynamins and dynamin-related GTPases.

  6. 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.

  7. Human adenosine deaminase: properties and turnover in cultured T and B lymphoblasts

    International Nuclear Information System (INIS)

    Daddona, P.E.

    1981-01-01

    In this study, the properties and rate of turnover of adenosine deaminase are compared in cultured human T and B lymphoblast cell lines. 1) Relative to B lymphoblasts, the level of adenosine deaminase activity in extracts of T lymphoblast cell lines (MOLT-4, RPMI-8402, CCRF-CEM, and CCRF-HSB-2) is elevated 7-14-fold and differs by 2-fold between the C cell lines. 2) In both T and B lymphoblast extracts, the enzyme is apparently identical, based on K/sub m/ for adenosine and deoxyadenosine, K/sub i/ for inosine, V/sub max/ for adenosine, /sub S20,w/, isoelectric pH, and heat stability. Furthermore, by radioimmunoassay, the quantity of adenosine deaminase-immunocreative protein is proportional to the level of enzyme activity in all cell lines studies. 3) Using a purification and selective immunoprecipitation technique, the enzyme turnover could be assessed in cell lines labeled with [ 35 S]methionine. The apparent rate of adenosine deaminase synthesis, relative to total protein, is 2-fold faster in both T cell lines (RPMI-8402 and CCRF-CEM) than in the B cell lines (MGL-8 and GM-130). The apparent half-life (tsub1/2) for the enzyme degradation is 19 and 39 h, respectively, in CCFR-CEM and RPMI-8402, while the tsub1/2 in both B cell lines is 7-9 h. From the net rate of synthesis and degradation, the T cell lines, respectively, exhibit approximately a 6- and 12-fold difference in adenosine deaminase turnover relative to B cells, consistent with the observed differences in enzyme activity. This study suggests that while adenosine deaminase is apparently identical in both T and B lymphoblast cell lines, alterations in both the rate of enzyme synthesis and degradation contribute to its high steady state level in T cells

  8. 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}.

  9. Studies on Transcriptional Incorporation of 5'-N-Triphosphates of 5'-Amino-5'-Deoxyribonucleosides.

    Directory of Open Access Journals (Sweden)

    Weronika Kotkowiak

    Full Text Available In this study, several RNA polymerases were used for the first time to examine the possibility of transcriptional incorporation of 5'-N-triphosphates of 5'-amino-5'-deoxyribonucleosides (5'NH NTPs. The T3, T7, Sp6 and T7 Y639F RNA polymerases were employed to show that the full-length transcript cannot be synthesized. The results suggest that the application of 5'NH NTPs could decrease transcription reaction rates. What is more, the modification of transcription conditions had no influence on the rate of 5'NH NTPs incorporation. Based on experimental data it is postulated that 5'NH NTPs can be used as potential transcription inhibitors. Our findings expand the knowledge on suitable uses of the 5'-N-triphosphates of 5'-amino-5'-deoxyribonucleoside and the exact mechanism of transcriptional inhibition.

  10. Excessive extracellular ATP desensitizes P2Y2 and P2X4 ATP receptors provoking surfactant impairment ending in ventilation-induced lung injury

    NARCIS (Netherlands)

    D. Hasan (Djo); Satalin, J. (Joshua); van der Zee, P. (Philip); Kollisch-Singule, M. (Michaela); P. Blankman (Paul); Shono, A. (Atsuko); P. Somhorst (Peter); C.A. den Uil (Corstiaan); H.J. Meeder (Han); Kotani, T. (Toru); G.F. Nieman (Gary F.)

    2018-01-01

    textabstractStretching the alveolar epithelial type I (AT I) cells controls the intercellular signaling for the exocytosis of surfactant by the AT II cells through the extracellular release of adenosine triphosphate (ATP) (purinergic signaling). Extracellular ATP is cleared by extracellular ATPases,

  11. Short-term increase of plasma free fatty acids does not interfere with intrinsic mitochondrial function in healthy young men

    NARCIS (Netherlands)

    Brands, Myrte; Hoeks, Joris; Sauerwein, Hans P.; Ackermans, Mariette T.; Ouwens, Margriet; Lammers, Nicolette M.; van der Plas, Mart N.; Schrauwen, Patrick; Groen, Albert K.; Serlie, Mireille J.

    2011-01-01

    Free fatty acid (FFA)- and obesity-induced insulin resistance has been associated with disturbed mitochondrial function. Elevated plasma FFA can impair insulin-induced increase of adenosine triphosphate synthesis and downregulate the expression of genes important in the biogenesis of mitochondria in

  12. A magnetic nanoparticle-clustering biosensor for blu-ray based optical detection of small-molecules

    DEFF Research Database (Denmark)

    Yang, Jaeyoung; Donolato, Marco; Antunes, Paula Soares Martins

    2014-01-01

    MNP-clustering facilitates high-resolution small-molecule assays. For experiments, aptamer-functionalized MNPs (Apt-MNPs) were first incubated with adenosine-5'-triphosphate (ATP) followed by adding MNPs with linker strands (linker-MNPs). The linker hybridizes with a region of aptamer sequences...

  13. Structural basis of the substrate specificity of Bacillus cereus adenosine phosphorylase

    Energy Technology Data Exchange (ETDEWEB)

    Dessanti, Paola [Cornell University, Ithaca, NY 14853-1301 (United States); Università di Sassari, (Italy); Zhang, Yang [Cornell University, Ithaca, NY 14853-1301 (United States); Allegrini, Simone [Università di Sassari, (Italy); Tozzi, Maria Grazia [Università di Pisa, (Italy); Sgarrella, Francesco [Università di Sassari, (Italy); Ealick, Steven E., E-mail: see3@cornell.edu [Cornell University, Ithaca, NY 14853-1301 (United States)

    2012-03-01

    Adenosine phosphorylase from B. cereus shows a strong preference for adenosine over other 6-oxopurine nucleosides. Mutation of Asp204 to asparagine reduces the efficiency of adenosine cleavage but does not affect inosine cleavage, effectively reversing the substrate specificity. The structures of D204N complexes explain these observations. Purine nucleoside phosphorylases catalyze the phosphorolytic cleavage of the glycosidic bond of purine (2′-deoxy)nucleosides, generating the corresponding free base and (2′-deoxy)ribose 1-phosphate. Two classes of PNPs have been identified: homotrimers specific for 6-oxopurines and homohexamers that accept both 6-oxopurines and 6-aminopurines. Bacillus cereus adenosine phosphorylase (AdoP) is a hexameric PNP; however, it is highly specific for 6-aminopurines. To investigate the structural basis for the unique substrate specificity of AdoP, the active-site mutant D204N was prepared and kinetically characterized and the structures of the wild-type protein and the D204N mutant complexed with adenosine and sulfate or with inosine and sulfate were determined at high resolution (1.2–1.4 Å). AdoP interacts directly with the preferred substrate through a hydrogen-bond donation from the catalytically important residue Asp204 to N7 of the purine base. Comparison with Escherichia coli PNP revealed a more optimal orientation of Asp204 towards N7 of adenosine and a more closed active site. When inosine is bound, two water molecules are interposed between Asp204 and the N7 and O6 atoms of the nucleoside, thus allowing the enzyme to find alternative but less efficient ways to stabilize the transition state. The mutation of Asp204 to asparagine led to a significant decrease in catalytic efficiency for adenosine without affecting the efficiency of inosine cleavage.

  14. Caffeine, Adenosine Receptors and Estrogen in Toxin Models of Parkinson's Disease

    National Research Council Canada - National Science Library

    Schwarzschild, Michael A; Xu, Kui

    2008-01-01

    ...) that are leading candidate modulators of PD risk. In Year 4 we have obtained and reported evidence that the adenosine receptor blocker caffeine as well as specific genetic depletion of the A2A subtype of adenosine receptor...

  15. Topical adenosine increases thick hair ratio in Japanese men with androgenetic alopecia.

    Science.gov (United States)

    Watanabe, Y; Nagashima, T; Hanzawa, N; Ishino, A; Nakazawa, Y; Ogo, M; Iwabuchi, T; Tajima, M

    2015-12-01

    Hair thickness is more important than hair density in the appearance of baldness in male with androgenetic alopecia (AGA). Adenosine improves hair loss by stimulating hair growth and by thickening hair shafts in women. The objective of this study was to evaluate the hair growth efficacy and safety of topical adenosine in men with AGA. A lotion containing either adenosine or niacinamide was administered to the scalps of 102 Japanese men twice daily for 6 months in a double-blind, randomized study. Efficacy was evaluated by dermatologists who assessed the quality of the hair and by calculating the percentages of vellus-like and thick hairs among the vertex hairs, as well as hair density. Adenosine was significantly (P < 0.05) superior to niacinamide in terms of global improvement of AGA, increase in the percentage of thick hairs (at least 60 μm) and self-assessment of hair thickness by the study participants. No causal adverse event due to the adenosine lotion was observed. These data indicate that adenosine increases thick hair ratio in Japanese men with AGA, and this compound is useful for the improvement of AGA. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  16. Sustained Elevated Adenosine via ADORA2B Promotes Chronic Pain through Neuro-immune Interaction

    Directory of Open Access Journals (Sweden)

    Xia Hu

    2016-06-01

    Full Text Available The molecular mechanisms of chronic pain are poorly understood and effective mechanism-based treatments are lacking. Here, we report that mice lacking adenosine deaminase (ADA, an enzyme necessary for the breakdown of adenosine, displayed unexpected chronic mechanical and thermal hypersensitivity due to sustained elevated circulating adenosine. Extending from Ada−/− mice, we further discovered that prolonged elevated adenosine contributed to chronic pain behaviors in two additional independent animal models: sickle cell disease mice, a model of severe pain with limited treatment, and complete Freund’s adjuvant paw-injected mice, a well-accepted inflammatory model of chronic pain. Mechanistically, we revealed that activation of adenosine A2B receptors on myeloid cells caused nociceptor hyperexcitability and promoted chronic pain via soluble IL-6 receptor trans-signaling, and our findings determined that prolonged accumulated circulating adenosine contributes to chronic pain by promoting immune-neuronal interaction and revealed multiple therapeutic targets.

  17. Time Window Is Important for Adenosine Preventing Cold-induced Injury to the Endothelium.

    Science.gov (United States)

    Li, Yan; Hu, Xiao-Xia; Fu, Li; Chen, Jing; Lu, Li-He; Liu, Xiang; Xu, Zhe; Zhou, Li; Wang, Zhi-Ping; Zhang, Xi; Ou, Zhi-Jun; Ou, Jing-Song

    2017-06-01

    Cold cardioplegia is used to induce heart arrest during cardiac surgery. However, endothelial function may be compromised after this procedure. Accordingly, interventions such as adenosine, that mimic the effects of preconditioning, may minimize endothelial injury. Herein, we investigated whether adenosine prevents cold-induced injury to the endothelium. Cultured human cardiac microvascular endothelial cells were treated with adenosine for different durations. Phosphorylation and expression of endothelial nitric oxide synthase (eNOS), p38MAPK, ERK1/2, and p70S6K6 were measured along with nitric oxide (NO) production using diaminofluorescein-2 diacetate (DAF-2DA) probe. Cold-induced injury by hypothermia to 4°C for 45 minutes to mimic conditions of cold cardioplegia during open heart surgery was induced in human cardiac microvascular endothelial cells. Under basal conditions, adenosine stimulated NO production, eNOS phosphorylation at serine 1177 from 5 minutes to 4 hours and inhibited eNOS phosphorylation at threonine 495 from 5 minutes to 6 hours, but increased phosphorylation of ERK1/2, p38MAPK, and p70S6K only after exposure for 5 minutes. Cold-induced injury inhibited NO production and the phosphorylation of the different enzymes. Importantly, adenosine prevented these effects of hypothermic injury. Our data demonstrated that adenosine prevents hypothermic injury to the endothelium by activating ERK1/2, eNOS, p70S6K, and p38MAPK signaling pathways at early time points. These findings also indicated that 5 minutes after administration of adenosine or release of adenosine is an important time window for cardioprotection during cardiac surgery.

  18. Adenosine-loaded dissolving microneedle patches to improve skin wrinkles, dermal density, elasticity and hydration.

    Science.gov (United States)

    Kang, G; Tu, T N T; Kim, S; Yang, H; Jang, M; Jo, D; Ryu, J; Baek, J; Jung, H

    2018-04-01

    Although dissolving microneedle patches have been widely studied in the cosmetics field, no comparisons have been drawn with the topical applications available for routine use. In this study, two wrinkle-improving products, adenosine-loaded dissolving microneedle patches and an adenosine cream, were evaluated for efficacy, with respect to skin wrinkling, dermal density, elasticity, and hydration, and safety in a clinical test on the crow's feet area. Clinical efficacy and safety tests were performed for 10 weeks on 22 female subjects with wrinkles around their eyes. The adenosine-loaded dissolving microneedle patch was applied once every 3 days, in the evening, for 8 weeks to the designated crow's feet area. The adenosine cream was applied two times per day, in the morning and evening, for 8 weeks to the other crow's feet area. Skin wrinkling, dermal density, elasticity, and hydration were measured by using PRIMOS ® premium, Dermascan ® C, Cutometer ® MPA580, and Corneometer ® CM 825, respectively. In addition, subjective skin irritation was evaluated by self-observation, and objective skin irritation was assessed through expert interviews. The adenosine-loaded dissolving microneedle patches had a similar or better efficacy than the adenosine cream. Both groups showed statistically significant efficacy for almost all parameters (P hydration efficacy (P skin-improvement parameters, adenosine-loaded dissolving microneedle patches showed the same or better effect than the adenosine cream, although the weekly adenosine dose was 140 times lower. The dissolving microneedle patches caused no adverse reactions. These adenosine-loaded dissolving microneedle patches are expected to be safe, effective, and novel cosmetics for skin improvement. © 2018 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  19. Fospropofol Disodium for Sedation in Elderly Patients Undergoing Flexible Bronchoscopy.

    Science.gov (United States)

    Silvestri, Gerard A; Vincent, Brad D; Wahidi, Momen M

    2011-01-01

    BACKGROUND: Fospropofol disodium is a water-soluble prodrug of propofol. A subset analysis was undertaken of elderly patients (≥65 y) undergoing flexible bronchoscopy, who were part of a larger multicenter, randomized, double-blind study. METHODS: Patients received fentanyl citrate (50 mcg) followed by fospropofol at initial (4.88mg/kg) and supplemental (1.63mg/kg) doses. The primary end point was sedation success (3 consecutive Modified Observer's Assessment of Alertness/Sedation scores of ≤4 and procedure completion without alternative sedative or assisted ventilation). Treatment success, time to fully alert, patient and physician satisfaction, and safety/tolerability were also evaluated. RESULTS: In the elderly patients subset (n=61), sedation success was 92%, the mean time to fully alert was 8.0±10.9 min, and memory retention was 72% during recovery, and these were comparable with the younger patients subgroup (age, Sedation-related adverse events occurred in 23% of the elderly and 18% of the younger patients (age, sedation, rapid time to fully alert, and high satisfaction in this elderly subset undergoing flexible bronchoscopy, which was comparable with outcomes in younger patients.

  20. Adenosine as an adjunct to thrombolytic therapy for acute myocardial infarction: results of a multicenter, randomized, placebo-controlled trial: the Acute Myocardial Infarction STudy of ADenosine (AMISTAD) trial.

    Science.gov (United States)

    Mahaffey, K W; Puma, J A; Barbagelata, N A; DiCarli, M F; Leesar, M A; Browne, K F; Eisenberg, P R; Bolli, R; Casas, A C; Molina-Viamonte, V; Orlandi, C; Blevins, R; Gibbons, R J; Califf, R M; Granger, C B

    1999-11-15

    The Acute Myocardial Infarction STudy of ADenosine (AMISTAD) trial was designed to test the hypothesis that adenosine as an adjunct to thrombolysis would reduce myocardial infarct size. Reperfusion therapy for acute myocardial infarction (MI) has been shown to reduce mortality, but reperfusion itself also may have deleterious effects. The AMISTAD trial was a prospective, open-label trial of thrombolysis with randomization to adenosine or placebo in 236 patients within 6 h of infarction onset. The primary end point was infarct size as determined by Tc-99 m sestamibi single-photon emission computed tomography (SPECT) imaging 6+/-1 days after enrollment based on multivariable regression modeling to adjust for covariates. Secondary end points were myocardial salvage index and a composite of in-hospital clinical outcomes (death, reinfarction, shock, congestive heart failure or stroke). In all, 236 patients were enrolled. Final infarct size was assessed in 197 (83%) patients. There was a 33% relative reduction in infarct size (p = 0.03) with adenosine. There was a 67% relative reduction in infarct size in patients with anterior infarction (15% in the adenosine group vs. 45.5% in the placebo group) but no reduction in patients with infarcts located elsewhere (11.5% for both groups). Patients randomized to adenosine tended to reach the composite clinical end point more often than those assigned to placebo (22% vs. 16%; odds ratio, 1.43; 95% confidence interval, 0.71 to 2.89). Many agents thought to attenuate reperfusion injury have been unsuccessful in clinical investigation. In this study, adenosine resulted in a significant reduction in infarct size. These data support the need for a large clinical outcome trial.

  1. Adenosine A(2A) receptor dynamics studied with the novel fluorescent agonist Alexa488-APEC.

    Science.gov (United States)

    Brand, Frank; Klutz, Athena M; Jacobson, Kenneth A; Fredholm, Bertil B; Schulte, Gunnar

    2008-08-20

    G protein-coupled receptors, such as the adenosine A(2A) receptor, are dynamic proteins, which undergo agonist-dependent redistribution from the cell surface to intracellular membranous compartments, such as endosomes. In order to study the kinetics of adenosine A(2A) receptor redistribution in living cells, we synthesized a novel fluorescent agonist, Alexa488-APEC. Alexa488-APEC binds to adenosine A(2A) (K(i)=149+/-27 nM) as well as A(3) receptors (K(i)=240+/-160 nM) but not to adenosine A(1) receptors. Further, we characterized the dose-dependent increase in Alexa488-APEC-induced cAMP production as well as cAMP response element binding (CREB) protein phosphorylation, verifying the ligand's functionality at adenosine A(2A) but not A(2B) receptors. In live-cell imaging studies, Alexa488-APEC-induced adenosine A(2A) receptor internalization, which was blocked by the competitive reversible antagonist ZM 241385 and hyperosmolaric sucrose. Further, internalized adenosine A(2A) receptors co-localized with clathrin and Rab5, indicating that agonist stimulation promotes adenosine A(2A) receptor uptake through a clathrin-dependent mechanism to Rab5-positive endosomes. The basic characterization of Alexa488-APEC described here showed that it provides a useful tool for tracing adenosine A(2A) receptors in vitro.

  2. Adenosine: an activity-dependent axonal signal regulating MAP kinase and proliferation in developing Schwann cells.

    Science.gov (United States)

    Stevens, Beth; Ishibashi, Tomoko; Chen, Jiang-Fan; Fields, R Douglas

    2004-02-01

    Nonsynaptic release of ATP from electrically stimulated dorsal root gangion (DRG) axons inhibits Schwann cell (SC) proliferation and arrests SC development at the premyelinating stage, but the specific types of purinergic receptor(s) and intracellular signaling pathways involved in this form of neuron-glia communication are not known. Recent research shows that adenosine is a neuron-glial transmitter between axons and myelinating glia of the CNS. The present study investigates the possibility that adenosine might have a similar function in communicating between axons and premyelinating SCs. Using a combination of pharmacological and molecular approaches, we found that mouse SCs in culture express functional adenosine receptors and ATP receptors, a far more complex array of purinergic receptors than thought previously. Adenosine, but not ATP, activates ERK/MAPK through stimulation of cAMP-linked A2(A) adenosine receptors. Both ATP and adenosine inhibit proliferation of SCs induced by platelet-derived growth factor (PDGF), via mechanisms that are partly independent. In contrast to ATP, adenosine failed to inhibit the differentiation of SCs to the O4+ stage. This indicates that, in addition to ATP, adenosine is an activity-dependent signaling molecule between axons and premyelinating Schwann cells, but that electrical activity, acting through adenosine, has opposite effects on the differentiation of myelinating glia in the PNS and CNS.

  3. Alterations in electrocardiogram of adenosine test for 99Tcm-MIBI myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Xie Boqia; Tian Yueqin; Zheng Lihui

    2011-01-01

    Objective: To analyze alterations in electrocardiogram (ECG) of adenosine test in 99 Tc m -MIBI myocardial perfusion imaging(MPI)SPECT study. Methods: A total of 641 patients were included in the study. The patients each underwent 99 Tc m -MIBI MPI with adenosine test. The ECGs were taken before, during, and after adenosine infusion. Results: In all, abnormal ECGs were found in 205(32.0%) patients. During adenosine infusion, 20.6%(132/641) of patients suffered from arrhythmia, 29.5%(39/132) had atrial premature beats, 34.1% (45/132) had premature ventricular beats, and 6.1% (8/132) had sinoatrial block. In addition, 5.3% (7/132) had first-, 24.2% (32/132) had second-, and 0.8% (1/132) had third-degree atrioventricular block (AVB). After adenosine infusion, 4.4%( 28/641) of patients suffered from arrhythmia, 57.1% (16/28) had atrial premature beats, 39.3% (11/28) had premature ventricular beats, and 3.6% (1/28) had sinoatrial block. The perfusion images showed ischemia in 36 patients and infarction in 8 patients. Adenosine infusion was terminated in 39 patients (6.1%) because of poorly tolerated side effects. However, no death or acute myocardial infarction occurred in the study. Conclusions: Adenosine pharmacologic test for 99 Tc m -MIBI MPI may result in relatively high incidence of arrhythmia in ECG monitoring. (authors)

  4. Age-dependent changes of presynaptic neuromodulation via A1-adenosine receptors in rat hippocampal slices.

    Science.gov (United States)

    Sperlágh, B; Zsilla, G; Baranyi, M; Kékes-Szabó, A; Vizi, E S

    1997-10-01

    The presynaptic neuromodulation of stimulation-evoked release of [3H]-acetylcholine by endogenous adenosine, via A1-adenosine receptors, was studied in superfused hippocampal slices taken from 4-, 12- and 24-month-old rats. 8-Cyclopentyl-1,3-dimethylxanthine (0.25 microM), a selective A1-receptor antagonist, increased significantly the electrical field stimulation-induced release of [3H]-acetylcholine in slices prepared from 4- and 12-month-old rats, showing a tonic inhibitory action of endogenous adenosine via stimulation of presynaptic A1-adenosine receptors. In contrast, 8-cyclopentyl-1,3-dimethylxanthine had no effect in 24-month-old rats. 2-Chloroadenosine (10 microM), an adenosine receptor agonist decreased the release of [3H]-acetylcholine in slices taken from 4- and 12-month-old rats, and no significant change was observed in slices taken from 24-month-old rats. In order to show whether the number/or affinity of the A1-receptors was affected in aged rats, [3H]-8-cyclopentyl-1,3-dimethylxanthine binding was studied in hippocampal membranes prepared from rats of different ages. Whereas the Bmax value was significantly lower in 2-year-old rats than in younger counterparts, the dissociation constant (Kd) was not affected by aging, indicating that the density rather than the affinity of adenosine receptors was altered. Endogenous adenosine levels present in the extracellular space were also measured in the superfusate by high performance liquid chromatography (HPLC) coupled with ultraviolet detection, and an age-related increase in the adenosine level was found. In summary, our results indicate that during aging the level of adenosine in the extracellular fluid is increased in the hippocampus. There is a downregulation and reduced responsiveness of presynaptic adenosine A1-receptors, and it seems likely that these changes are due to the enhanced adenosine level in the extracellular space.

  5. Adenosine deaminase-related growth factors stimulate cell proliferation in Drosophila by depleting extracellular adenosine

    Czech Academy of Sciences Publication Activity Database

    Žurovec, Michal; Doležal, Tomáš; Gaži, Michal; Pavlová, Eva; Bryant, P. J.

    2002-01-01

    Roč. 99, č. 7 (2002), s. 4403-4408 ISSN 0027-8424 R&D Projects: GA ČR GA204/01/1022; GA AV ČR IAA5007107 Institutional research plan: CEZ:AV0Z5007907 Keywords : adenosine daminase * minimal medium Subject RIV: CE - Biochemistry Impact factor: 10.701, year: 2002

  6. Actions of p-synephrine on hepatic enzyme activities linked to carbohydrate metabolism and ATP levels in vivo and in the perfused rat liver.

    Science.gov (United States)

    Maldonado, Marcos Rodrigues; Bracht, Lívia; de Sá-Nakanishi, Anacharis Babeto; Corrêa, Rúbia Carvalho Gomes; Comar, Jurandir Fernando; Peralta, Rosane Marina; Bracht, Adelar

    2018-01-01

    p-Synephrine is one of the main active components of the fruit of Citrus aurantium (bitter orange). Extracts of the bitter orange and other preparations containing p-synephrine have been used worldwide to promote weight loss and for sports performance. The purpose of the study was to measure the action of p-synephrine on hepatic enzyme activities linked to carbohydrate and energy metabolism and the levels of adenine mononucleotides. Enzymes and adenine mononucleotides were measured in the isolated perfused rat liver and in vivo after oral administration of the drug (50 and 300 mg/kg) by using standard techniques. p-Synephrine increased the activity of glycogen phosphorylase in vivo and in the perfused liver. It decreased, however, the activities of pyruvate kinase and pyruvate dehydrogenase also in vivo and in the perfused liver. p-Synephrine increased the hepatic pools of adenosine diphosphate and adenosine triphosphate. Stimulation of glycogen phosphorylase is consistent with the reported increased glycogenolysis in the perfused liver and increased glycemia in rats. The decrease in the pyruvate dehydrogenase activity indicates that p-synephrine is potentially capable of inhibiting the transformation of carbohydrates into lipids. The capability of increasing the adenosine triphosphate-adenosine diphosphate pool indicates a beneficial effect of p-synephrine on the cellular energetics. Copyright © 2017 John Wiley & Sons, Ltd.

  7. Application of DBNPA dosage for biofouling control in spiral wound membrane systems

    KAUST Repository

    Siddiqui, Amber; Pinel, I.; Prest, E.I.; Bucs, Szilard; van Loosdrecht, M.C.M.; Kruithof, J.C.; Vrouwenvelder, Johannes S.

    2017-01-01

    in MFS was quantified by adenosine triphosphate (ATP) and total organic carbon (TOC) analysis. Continuous dosage of DBNPA (1 mg/L) prevented pressure drop increase and biofilm accumulation in the MFSs during a run time of 7 d, showing that biofouling can

  8. Promotion of mitochondrial membrane complex assembly by a proteolytically inactive yeast Lon

    NARCIS (Netherlands)

    Rep, M; van Dijl, J M; Suda, K; Schatz, G; Grivell, L A; Suzuki, C K

    1996-01-01

    Afg3p and Rca1p are adenosine triphosphate (ATP)-dependent metalloproteases in yeast mitochondria. Cells lacking both proteins exhibit defects in respiration-dependent growth, degradation of mitochondrially synthesized proteins, and assembly of inner-membrane complexes. Defects in growth and protein

  9. Role of breast cancer resistance protein in the bioavailability and fetal penetration of topotecan

    NARCIS (Netherlands)

    Jonker, JW; Smit, JW; Brinkhuis, RF; Maliepaard, M; Beijnen, JH; Schellens, JHM; Schinkel, AH

    2000-01-01

    Background and Methods: Breast cancer resistance protein (BCRP/MXR/ABCP) is a multidrug-resistance protein that is a member of the adenosine triphosphate-binding cassette family of drug transporters. BCRP can render tumor cells resistant to the anticancer drugs topotecan, mitoxantrone, doxorubicin,

  10. Quantitative biofouling diagnosis in full scale nanofiltration and reverse osmosis installations

    NARCIS (Netherlands)

    Vrouwenvelder, J.S.; Manolarakis, S.A.; van der Hoek, J.P.; van Paassen, J.A.M.; van der Meer, Walterus Gijsbertus Joseph; van Agtmaal, J.M.C.; Prummel, H.D.M.; Kruithof, J.C.; Loosdrecht, M.C.M.

    2008-01-01

    Biofilm accumulation in nanofiltration and reverse osmosis membrane elements results in a relative increase of normalised pressure drop (ΔNPD). However, an increase in ΔNPD is not exclusively linked to biofouling. In order to quantify biofouling, the biomass parameters adenosine triphosphate (ATP),

  11. The chromatin-remodeling factor CHD4 coordinates signaling and repair after DNA damage

    DEFF Research Database (Denmark)

    Larsen, Dorthe Helena; Poinsignon, Catherine; Gudjonsson, Thorkell

    2010-01-01

    In response to ionizing radiation (IR), cells delay cell cycle progression and activate DNA repair. Both processes are vital for genome integrity, but the mechanisms involved in their coordination are not fully understood. In a mass spectrometry screen, we identified the adenosine triphosphate...

  12. Free-energy carriers in human cultured muscle cells

    NARCIS (Netherlands)

    Bolhuis, P. A.; de Zwart, H. J.; Ponne, N. J.; de Jong, J. M.

    1985-01-01

    Creatine phosphate (CrP), adenosine triphosphate (ATP), creatine kinase (CK), adenylate kinase (AK), protein, and DNA were quantified in human muscle cell cultures undergoing transition from dividing myoblasts to multinucleate myotubes. CrP is negligible in cultures grown in commonly applied media

  13. The regulation of aortic endothelial cells by purines and pyrimidines involves co-existing P2y-purinoceptors and nucleotide receptors linked to phospholipase C.

    OpenAIRE

    Wilkinson, G. F.; Purkiss, J. R.; Boarder, M. R.

    1993-01-01

    1. We have examined the phospholipase C responses in bovine aortic endothelial cells to purines (ATP, ADP and analogues) and the pyrimidine, uridine triphosphate (UTP). 2. The cells responded to purines in a manner consistent with the presence of P2y purinoceptors; both 2-methylthioadenosine 5'-triphosphate (2MeSATP) and adenosine 5'-0-(2-thiodiphosphate) (ADP beta S) were potent agonists (EC50 0.41 microM and 0.85 microM respectively) while beta, gamma-methylene ATP at 300 microM was not. 3....

  14. The effect of nucleotides and adenosine on stimulus-evoked glutamate release from rat brain cortical slices.

    Science.gov (United States)

    Bennett, G C; Boarder, M R

    2000-10-01

    Evidence has previously been presented that P1 receptors for adenosine, and P2 receptors for nucleotides such as ATP, regulate stimulus-evoked release of biogenic amines from nerve terminals in the brain. Here we investigated whether adenosine and nucleotides exert presynaptic control over depolarisation-elicited glutamate release. Slices of rat brain cortex were perfused and stimulated with pulses of 46 mM K(+) in the presence of the glutamate uptake inhibitor L-trans-pyrrolidine-2,4-dicarboxylic acid (0.2 mM). High K(+) substantially increased efflux of glutamate from the slices. Basal glutamate release was unchanged by the presence of nucleotides or adenosine at concentrations of 300 microM. Adenosine, ATP, ADP and adenosine 5'-O-(3-thiotriphoshate) at 300 microM attenuated depolarisation-evoked release of glutamate. However UTP, 2-methylthio ATP, 2-methylthio ADP, and alpha,beta-methylene ATP at 300 microM had no effect on stimulated glutamate efflux. Adenosine deaminase blocked the effect of adenosine, but left the response to ATP unchanged. The A(1) antagonist 8-cyclopentyl-1, 3-dipropylxanthine antagonised the inhibitory effect of both adenosine and ATP. Cibacron blue 3GA inhibited stimulus-evoked glutamate release when applied alone. When cibacron blue 3GA was present with ATP, stimulus-evoked glutamate release was almost eliminated. However, this P2 antagonist had no effect on the inhibition by adenosine. These results show that the release of glutamate from depolarised nerve terminals of the rat cerebral cortex is inhibited by adenosine and ATP. ATP appears to act directly and not through conversion to adenosine.

  15. Role of P2X7 on steroid synthesis in murine luteal cells

    Directory of Open Access Journals (Sweden)

    Chunping Zhang

    2016-03-01

    Full Text Available The extracellular adenosine triphosphate (ATP regulates different cellular functions through activating purinergic receptors as a signalling molecule or neurotransmitter. P2X7 is highly expressed in murine small luteal cells. In this study, murine luteal cells were cultured in vitro and treated with P2X7 agonists – ATP and 2′(3′-O-(4-benzoyl-benzoyl-adenosine 50-triphosphate (BzATP and with P2X7 antagonist – brilliant blue G (BBG. We found that ATP and BzATP increased the production of progesterone and had no influence on the production of estradiol. BBG reversed the effect of BzATP and ATP. Further studies demonstrated that ATP and BzATP promoted the expression of CYP11A. These results revealed that P2X7 receptor activation is involved in the steroid synthesis in corpus luteum.

  16. The stochastic chemomechanics of the F(1)-ATPase molecular motor.

    Science.gov (United States)

    Gaspard, P; Gerritsma, E

    2007-08-21

    We report a theoretical study of the F(1)-ATPase molecular rotary motor experimentally studied by R. Yasuda, H. Noji, M. Yoshida, K. Kinosita Jr., H. Itoh [Nature 410 (2001) 898]. The motor is modeled as a stochastic process for the angle of its shaft and the chemical state of its catalytic sites. The stochastic process is ruled by six coupled Fokker-Planck equations for the biased diffusion of the angle and the random jumps between the chemical states. The model reproduces the experimental observations that the motor proceeds by substeps and the rotation rate saturates at high concentrations of adenosine triphosphate or at low values of the friction coefficient. Moreover, predictions are made about the dependence of the rotation rate on temperature, and about the behavior of the F(1) motor under the effect of an external torque, especially, in the regime of synthesis of adenosine triphosphate.

  17. Adenosine triphosphate stimulates Aquifex aeolicus MutL endonuclease activity.

    Directory of Open Access Journals (Sweden)

    Jerome Mauris

    2009-09-01

    Full Text Available 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.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.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.

  18. Adenosine A2A Receptor Modulates the Activity of Globus Pallidus Neurons in Rats

    Directory of Open Access Journals (Sweden)

    Hui-Ling Diao

    2017-11-01

    Full Text Available The globus pallidus is a central nucleus in the basal ganglia motor control circuit. Morphological studies have revealed the expression of adenosine A2A receptors in the globus pallidus. To determine the modulation of adenosine A2A receptors on the activity of pallidal neurons in both normal and parkinsonian rats, in vivo electrophysiological and behavioral tests were performed in the present study. The extracellular single unit recordings showed that micro-pressure administration of adenosine A2A receptor agonist, CGS21680, regulated the pallidal firing activity. GABAergic neurotransmission was involved in CGS21680-induced modulation of pallidal neurons via a PKA pathway. Furthermore, application of two adenosine A2A receptor antagonists, KW6002 or SCH442416, mainly increased the spontaneous firing of pallidal neurons, suggesting that endogenous adenosine system modulates the activity of pallidal neurons through adenosine A2A receptors. Finally, elevated body swing test (EBST showed that intrapallidal microinjection of adenosine A2A receptor agonist/antagonist induced ipsilateral/contralateral-biased swing, respectively. In addition, the electrophysiological and behavioral findings also revealed that activation of dopamine D2 receptors by quinpirole strengthened KW6002/SCH442416-induced excitation of pallidal activity. Co-application of quinpirole with KW6002 or SCH442416 alleviated biased swing in hemi-parkinsonian rats. Based on the present findings, we concluded that pallidal adenosine A2A receptors may be potentially useful in the treatment of Parkinson's disease.

  19. Use of image processing techniques to assess effect of disodium pamidronate in conjunction with radiotherapy in patients with bone metastases

    International Nuclear Information System (INIS)

    Kouloulias, Vassilios E.; Dardoufas, Costas E.; Kouvaris, John R.; Antypas, Christos E.; Sandilos, Panagiotis H.; Matsopoulos, George K.; Vlahos, Lambros J.

    2002-01-01

    The aim of this study was radiographically to monitor the effect of disodium pamidronate on metastatic bone disease, using image-processing techniques. Eighteen patients with osteolytic metastases from breast cancer received an intravenous infusion of 180 mg disodium pamidronate every 4 weeks for a period of 6 months. The first session of intravenous infusions was given concurrently with external beam radiotherapy with a 6 MV linear accelerator (total dose 30 Gy in 10 fractions). Radiographs of osteolytic lesions were obtained at every session of the treatment, retaining the same settings for each modality. The analysis of the attributes of the images was based on measuring the first-order statistics of the gray-level histogram in terms of mean value (MVGLH) and energy (EGLH). The measurements showed significant differences for MVGLH and EGLH values (p<0.05, Wilcoxon test). Analytically, there was an 11.08% (95% CI=10.21, 11.93) mean reduction of EGLH and an 11.63% (95% CI=10.96, 12.29) mean increase of MVGLH of the x-ray images, before and after the combined treatment protocol. The changes in the image-processing indices were also highly correlated with the reduction of the patient's pain score. These findings indicate an important increase in bone mass and bone formation, which the radiologists found difficult to identify visually

  20. Use of image processing techniques to assess effect of disodium pamidronate in conjunction with radiotherapy in patients with bone metastases

    Energy Technology Data Exchange (ETDEWEB)

    Kouloulias, Vassilios E.; Dardoufas, Costas E.; Kouvaris, John R.; Antypas, Christos E.; Sandilos, Panagiotis H.; Matsopoulos, George K.; Vlahos, Lambros J. [Areteion Univ. Hospital Athens (Greece). Radiotherapy Dept.

    2002-04-01

    The aim of this study was radiographically to monitor the effect of disodium pamidronate on metastatic bone disease, using image-processing techniques. Eighteen patients with osteolytic metastases from breast cancer received an intravenous infusion of 180 mg disodium pamidronate every 4 weeks for a period of 6 months. The first session of intravenous infusions was given concurrently with external beam radiotherapy with a 6 MV linear accelerator (total dose 30 Gy in 10 fractions). Radiographs of osteolytic lesions were obtained at every session of the treatment, retaining the same settings for each modality. The analysis of the attributes of the images was based on measuring the first-order statistics of the gray-level histogram in terms of mean value (MVGLH) and energy (EGLH). The measurements showed significant differences for MVGLH and EGLH values (p<0.05, Wilcoxon test). Analytically, there was an 11.08% (95% CI=10.21, 11.93) mean reduction of EGLH and an 11.63% (95% CI=10.96, 12.29) mean increase of MVGLH of the x-ray images, before and after the combined treatment protocol. The changes in the image-processing indices were also highly correlated with the reduction of the patient's pain score. These findings indicate an important increase in bone mass and bone formation, which the radiologists found difficult to identify visually.

  1. Polymorphisms in adenosine receptor genes are associated with infarct size in patients with ischemic cardiomyopathy.

    Science.gov (United States)

    Tang, Z; Diamond, M A; Chen, J-M; Holly, T A; Bonow, R O; Dasgupta, A; Hyslop, T; Purzycki, A; Wagner, J; McNamara, D M; Kukulski, T; Wos, S; Velazquez, E J; Ardlie, K; Feldman, A M

    2007-10-01

    The goal of this experiment was to identify the presence of genetic variants in the adenosine receptor genes and assess their relationship to infarct size in a population of patients with ischemic cardiomyopathy. Adenosine receptors play an important role in protecting the heart during ischemia and in mediating the effects of ischemic preconditioning. We sequenced DNA samples from 273 individuals with ischemic cardiomyopathy and from 203 normal controls to identify the presence of genetic variants in the adenosine receptor genes. Subsequently, we analyzed the relationship between the identified genetic variants and infarct size, left ventricular size, and left ventricular function. Three variants in the 3'-untranslated region of the A(1)-adenosine gene (nt 1689 C/A, nt 2206 Tdel, nt 2683del36) and an informative polymorphism in the coding region of the A3-adenosine gene (nt 1509 A/C I248L) were associated with changes in infarct size. These results suggest that genetic variants in the adenosine receptor genes may predict the heart's response to ischemia or injury and might also influence an individual's response to adenosine therapy.

  2. Cytidine triphosphate synthase activity and mRNA expression in normal human blood cells

    NARCIS (Netherlands)

    Verschuur, A. C.; van Gennip, A. H.; Muller, E. J.; Voûte, P. A.; Vreken, P.; van Kuilenburg, A. B.

    1999-01-01

    Cytidine triphosphate (CTP) synthase is one of the key enzymes in pyrimidine nucleotide anabolic pathways. The activity of this enzyme is elevated in various malignancies including acute lymphocytic leukemia (ALL). In this study we investigated the activity of CTP synthase in various human blood

  3. Quenching characteristics of bathocuproinedisulfonic acid, disodium salt in aqueous solution and copper sulfate plating solution

    Science.gov (United States)

    Koga, Toshiaki; Hirakawa, Chieko; Takeshita, Michinori; Terasaki, Nao

    2018-04-01

    Bathocuproinedisulfonic acid, disodium salt (BCS) is generally used to detect Cu(I) through a color reaction. We newly found BCS fluorescence in the visible blue region in an aqueous solution. However, the fluorescence mechanism of BCS is not well known, so we should investigate its fundamental information. We confirmed that the characteristics of fluorescence are highly dependent on the molecular concentration and solvent properties. In particular, owing to the presence of the copper compound, the fluorescence intensity extremely decreases. By fluorescence quenching, we observed that a copper compound concentration of 10-6 mol/L or less could easily be measured in an aqueous solution. We also observed BCS fluorescence in copper sulfate plating solution and the possibility of detecting monovalent copper by fluorescence reabsorption.

  4. Gadoxetate disodium-enhanced MR imaging: Differentiation between early-enhancing non-tumorous lesions and hypervascular hepatocellular carcinomas

    Energy Technology Data Exchange (ETDEWEB)

    Goshima, Satoshi, E-mail: gossy@par.odn.ne.jp [Department of Radiology, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1193 (Japan); Kanematsu, Masayuki [Department of Radiology, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1193 (Japan); Department of Radiology Services, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1193 (Japan); Watanabe, Haruo; Kondo, Hiroshi; Mizuno, Nozomi; Kawada, Hiroshi [Department of Radiology, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1193 (Japan); Shiratori, Yoshimune [Department of Medical Informatics, Gifu University School of Medicine, Gifu (Japan); Onozuka, Minoru [Department of Physiology and Neuroscience, Kanagawa Dental College, Yokosuka (Japan); Moriyama, Noriyuki [Research Center for Cancer Prevention and Screening, National Cancer Center Hospital, Tsukiji (Japan); Bae, Kyongtae T. [Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, PA (United States)

    2011-08-15

    Purpose: To retrospectively assess imaging features that help differentiate early-enhancing non-tumorous (EN) hepatic lesions from hepatocellular carcinomas (HCCs) on gadoxetate disodium-enhanced MR imaging. Materials and methods: Our institutional review board approved this retrospective study. We reviewed the studies of 158 patients (92 men and 65 women; age range: 29-91; mean age: 65.6 years) with chronic liver damage, who underwent gadoxetate disodium-enhanced MR imaging at 3T MR scanner. Hypervascular lesions identified during the hepatic artery phase were selected for a study cohort. The location, shape, size (maximum diameter and maximum area), and contrast enhancement signal intensity characteristics of the lesions were evaluated, then compared between the EN and HCC lesions. Results: A total of 65 EN lesions (range: 3-60 mm, mean: 13.6 {+-} 10.6 mm) from 35 patients and 33 HCCs (range: 9-61 mm, mean: 19.3 {+-} 12.6 mm) from 20 patients were identified. Lesions were more frequently round or oval in shape for HCCs (n = 29; 88%) than ENs (n = 26; 40%) (P < 0.01). Unexpectedly, some ENs (n = 12; 18%) showed hypointensity on hepatocyte-phase, and 6 (50%) of them were T2 hyperintense. For lesions smaller than 2 cm (9 ENs and 21 HCCs) on hepatic arterial-phase images, the mean area of hypointensity in hepatocyte-phase (54.2 {+-} 33.1 mm{sup 2}) was significantly smaller than those of the corresponding hyperintensity in hepatic arterial-phase (97.1 {+-} 42.0 mm{sup 2}) for EN lesions (P = 0.019), whereas no significant difference in area was found for HCCs. Conclusion: EN lesions may occasionally present with hypointensity during the hepatocyte-phase; presenting a diagnostic dilemma. In this situation, EN lesions may be differentiated from HCCs when a hypointense area in hepatocyte-phase is smaller than the corresponding hypervascular area in hepatic-arterial phase.

  5. Three minute versus six minute adenosine infusion in myocardial perfusion scintigraphy

    International Nuclear Information System (INIS)

    Gopinath, G.; Naojee, S.A.; Croasdale, J.; Johnson, G.; Hilson, A.J.W.; Buscombe, J.R.

    2003-01-01

    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)

  6. Purinergic signaling modulates the cerebral inflammatory response in experimentally infected fish with Streptococcus agalactiae: an attempt to improve the immune response.

    Science.gov (United States)

    Souza, Carine F; Baldissera, Matheus D; Bottari, Nathiele B; Moreira, Karen L S; da Rocha, Maria Izabel U M; da Veiga, Marcelo L; Santos, Roberto C V; Baldisserotto, Bernardo

    2018-06-01

    Appropriate control of the immune response is a critical determinant of fish health, and the purinergic cascade has an important role in the immune and inflammatory responses. This cascade regulates the levels of adenosine triphosphate (ATP), adenosine diphosphate, adenosine monophosphate and adenosine (Ado), molecules involved in physiological or pathological events as inflammatory and anti-inflammatory mediators. Thus, the aim of this study was to evaluate whether purinergic signaling, through the activities of nucleoside triphosphate diphosphohydrolase (NTPDase), 5'-nucleotidase, and adenosine deaminase (ADA), is capable of modulating the cerebral immune and inflammatory responses in silver catfish that is experimentally infected with Streptococcus agalactiae. Cerebral NTPDase (with ATP as substrate) and 5'-nucleotidase activities increased, while ADA activity decreased in silver catfish that is experimentally infected with S. agalactiae, compared to the control group. Moreover, the cerebral levels of ATP and Ado increased in infected animals compared to the uninfected control group. Brain histopathology in infected animals revealed inflammatory demyelination (the presence of occasional bubbly collections), increased cellular density in the area near to pia-mater and intercellular edema. Based on this evidence, the modulation of the purinergic cascade by the enzymes NTPDase, 5'-nucleotidase, and ADA exerts an anti-inflammatory profile due to the regulation of ATP and Ado levels. This suggests involvement of purinergic enzymes on streptococcosis pathogenesis, through regulating cerebral ATP and Ado levels, molecules known to participate in physiological or pathological events as inflammatory and anti-inflammatory mediators, respectively. In summary, the modulation of the cerebral purinergic cascade exerts an anti-inflammatory profile in an attempt to reduce inflammatory damage.

  7. 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

  8. Extracellular adenosine-induced Rac1 activation in pulmonary endothelium: Molecular mechanisms and barrier-protective role.

    Science.gov (United States)

    Kovacs-Kasa, Anita; Kim, Kyung Mi; Cherian-Shaw, Mary; Black, Stephen M; Fulton, David J; Verin, Alexander D

    2018-08-01

    We have previously shown that Gs-coupled adenosine receptors (A2a) are primarily involved in adenosine-induced human pulmonary artery endothelial cell (HPAEC) barrier enhancement. However, the downstream events that mediate the strengthening of the endothelial cell (EC) barrier via adenosine signaling are largely unknown. In the current study, we tested the overall hypothesis that adenosine-induced Rac1 activation and EC barrier enhancement is mediated by Gs-dependent stimulation of cAMP-dependent Epac1-mediated signaling cascades. Adenoviral transduction of HPAEC with constitutively-active (C/A) Rac1 (V12Rac1) significantly increases transendothelial electrical resistance (TER) reflecting an enhancement of the EC barrier. Conversely, expression of an inactive Rac1 mutant (N17Rac1) decreases TER reflecting a compromised EC barrier. The adenosine-induced increase in TER was accompanied by activation of Rac1, decrease in contractility (MLC dephosphorylation), but not Rho inhibition. Conversely, inhibition of Rac1 activity attenuates adenosine-induced increase in TER. We next examined the role of cAMP-activated Epac1 and its putative downstream targets Rac1, Vav2, Rap1, and Tiam1. Depletion of Epac1 attenuated the adenosine-induced Rac1 activation and the increase in TER. Furthermore, silencing of Rac1 specific guanine nucleotide exchange factors (GEFs), Vav2 and Rap1a expression significantly attenuated adenosine-induced increases in TER and activation of Rac1. Depletion of Rap1b only modestly impacted adenosine-induced increases in TER and Tiam1 depletion had no effect on adenosine-induced Rac1 activation and TER. Together these data strongly suggest that Rac1 activity is required for adenosine-induced EC barrier enhancement and that the activation of Rac1 and ability to strengthen the EC barrier depends, at least in part, on cAMP-dependent Epac1/Vav2/Rap1-mediated signaling. © 2017 Wiley Periodicals, Inc.

  9. Altered sarco(endo)plasmic reticulum calcium adenosine triphosphatase 2a content: Targets for heart failure therapy.

    Science.gov (United States)

    Liu, Gang; Li, Si Qi; Hu, Ping Ping; Tong, Xiao Yong

    2018-05-01

    Sarco(endo)plasmic reticulum calcium adenosine triphosphatase is responsible for transporting cytosolic calcium into the sarcoplasmic reticulum and endoplasmic reticulum to maintain calcium homeostasis. Sarco(endo)plasmic reticulum calcium adenosine triphosphatase is the dominant isoform expressed in cardiac tissue, which is regulated by endogenous protein inhibitors, post-translational modifications, hormones as well as microRNAs. Dysfunction of sarco(endo)plasmic reticulum calcium adenosine triphosphatase is associated with heart failure, which makes sarco(endo)plasmic reticulum calcium adenosine triphosphatase a promising target for heart failure therapy. This review summarizes current approaches to ameliorate sarco(endo)plasmic reticulum calcium adenosine triphosphatase function and focuses on phospholamban, an endogenous inhibitor of sarco(endo)plasmic reticulum calcium adenosine triphosphatase, pharmacological tools and gene therapies.

  10. Exploiting Chemical Libraries, Structure, and Genomics in the Search for Kinase Inhibitors

    NARCIS (Netherlands)

    Gray, Nathanael S.; Wodicka, Lisa; Thunnissen, Andy-Mark W.H.; Norman, Thea C.; Kwon, Soojin; Espinoza, F. Hernan; Morgan, David O.; Barnes, Georjana; LeClerc, Sophie; Meijer, Laurent; Kim, Sung-Hou; Lockhart, David J.; Schultz, Peter G.

    1998-01-01

    Selective protein kinase inhibitors were developed on the basis of the unexpected binding mode of 2,6,9-trisubstituted purines to the adenosine triphosphate-binding site of the human cyclin-dependent kinase 2 (CDK2). By iterating chemical library synthesis and biological screening, potent inhibitors

  11. Contractile responses to ergotamine and dihydroergotamine in the perfused middle cerebral artery of rat

    DEFF Research Database (Denmark)

    Tfelt-Hansen, Peer; Nilsson, Elisabeth; Edvinsson, Lars

    2007-01-01

    mmHg and luminally perfused. All vessels used attained spontaneous contractile tone (34.9+/-1.8% of resting tone) and responded to luminal adenosine triphosphate (ATP) with dilatation (24.1+/-4.0%), which showed functioning endothelium. Luminally added ergotamine or DHE induced maximal contractions...

  12. Duration of Red Blood Cell Storage Is Associated with Increased Incidence of Deep Vein Thrombosis and in Hospital Mortality in Patients with Traumatic Injuries

    Science.gov (United States)

    2009-09-22

    Verhoeven AJ: Prolonged maintenance of 2, 3- diphosphoglycerate acid and adenosine triphosphate in red blood cells during storage. Transfusion 2008...ABO blood group geno- type and factor VIII levels as independent risk factors for venous thromboembolism. Thromb Haemost 2005, 93(3):468-474. 41. Koch

  13. Rejuvenation of stored human red blood cells reverses the renal microvascular oxygenation deficit in an isovolemic transfusion model in rats

    NARCIS (Netherlands)

    Raat, Nicolaas J. H.; Hilarius, Petra M.; Johannes, Tanja; de Korte, Dirk; Ince, Can; Verhoeven, Arthur J.

    2009-01-01

    BACKGROUND: Storage of red blood cells (RBCs) results in various biochemical changes, including a decrease in cellular adenosine triphosphate and 2,3-diphosphoglycerate acid. Previously it was shown that stored human RBCs show a deficit in the oxygenation of the microcirculation in the gut of

  14. Adenosine metabolism in Toxoplasma gondii: potential targets for chemotherapy.

    Science.gov (United States)

    el Kouni, Mahmoud H

    2007-01-01

    Toxoplasma gondii is an intracellular parasitic protozoan that infects approximately a billion people worldwide. Infection with T. gondii represents a major health problem for immunocompromised individuals, such as AIDS patients, organ transplant recipients, and the unborn children of infected mothers. Currently available drugs usually do not eradicate infection and as many as 50% of the patients do not respond to this therapy. Furthermore, they are ineffective against T. gondii tissue cysts. In addition, prolonged exposure to these drugs induces serious host toxicity forcing the discontinuation of the therapy. Finally, there is no effective vaccine currently available for the treatment of toxoplasmosis. Therefore, it is necessary to develop new and effective drugs for the treatment and management of toxoplasmosis. The rational design of a drug depends on the exploitation of fundamental biochemical or physiological differences between pathogens and their host. Some of the most striking differences between T. gondii and their mammalian host are found in purine metabolism. T. gondii, like most parasites studied, lack the ability to synthesize purines do novo and depend on the salvage of purines from their host to satisfy their requirements of purines. In this respect, the salvage of adenosine is the major source of purines in T. gondii. Therefore, interference with adenosine uptake and metabolism in T. gondii can be selectively detrimental to the parasite. The host cells, on the other hand, can still obtain their purine requirements by their de novo pathways. This review will focus on the broad aspects of the adenosine transport and the enzyme adenosine kinase (EC 2.7.1.20) which are the two primary routes for adenosine utilization in T. gondii, in an attempt to illustrate their potentials as targets for chemotherapy against this parasite.

  15. Intercalation of gaseous thiols and sulfides into Ag+ ion-exchanged aluminum dihydrogen triphosphate.

    Science.gov (United States)

    Hayashi, Aki; Saimen, Hiroki; Watanabe, Nobuaki; Kimura, Hitomi; Kobayashi, Ayumi; Nakayama, Hirokazu; Tsuhako, Mitsutomo

    2005-08-02

    Ag(+) ion-exchanged layered aluminum dihydrogen triphosphate (AlP) with the interlayer distance of 0.85 nm was synthesized by the ion-exchange of proton in triphosphate with Ag(+) ion. The amount of exchanged Ag(+) ion depended on the concentration of AgNO(3) aqueous solution. Ag(+) ion-exchanged AlP adsorbed gaseous thiols and sulfides into the interlayer region. The adsorption amounts of thiols were more than those of sulfides, thiols with one mercapto group > thiol with two mercapto groups > sulfides, and depended on the amount of exchanged Ag(+) ion in the interlayer region. The thiols with one mercapto group were intercalated to expand the interlayer distance of Ag(+) ion-exchanged AlP, whereas there was no expansion in the adsorption of sulfide. In the case of thiol with two mercapto groups, there was observed contraction of the interlayer distance through the bridging with Ag(+) ions of the upper and lower sides of the interlayer region.

  16. Safety of adenosine stress myocardial perfusion imaging by a one-route infusion protocol

    International Nuclear Information System (INIS)

    Kawai, Yuko; Kishino, Koh

    2006-01-01

    When adenosine stress testing is performed, a vein is generally accessed in each arm. To determine whether the one-route infusion protocol, that is, infusion via one upper arm vein, is safe, myocardial perfusion imaging was performed during adenosine stress testing in patients with angina pectoris. Sixty-six consecutive patients (43 men, 68±11 years of age) with suspected coronary artery disease were enrolled in this study. For the stress test, adenosine was injected at 120 μg/kg/min for 6 minutes. Systolic blood pressure, diastolic blood pressure, and heart rate did not show any significant changes after injection of the adenosine and radioisotope (RI) tracer. Adverse events during infusion of the adenosine were seen in 42 (64%) patients and included chest discomfort/oppression in 17 (26%) and dyspnea/throat discomfort in 15 (23%). On the other hand, adverse events just after infusion of the RI tracer occurred in 5 (8%) patients and included chest oppression in 2 (3%) and dyspnea in 1 (2%). Almost all adverse events disappeared quickly without treatment. Therefore, we concluded that adenosine stress myocardial perfusion imaging using a one-route infusion protocol is safe and useful to do for patients unable to secure veins in both arms. (author)

  17. Protection against methamphetamine-induced neurotoxicity to neostriatal dopaminergic neurons by adenosine receptor activation.

    Science.gov (United States)

    Delle Donne, K T; Sonsalla, P K

    1994-12-01

    Methamphetamine (METH)-induced neurotoxicity to nigrostriatal dopaminergic neurons in experimental animals appears to have a glutamatergic component because blockade of N-methyl-D-aspartate receptors prevents the neuropathologic consequences. Because adenosine affords neuroprotection against various forms of glutamate-mediated neuronal damage, the present studies were performed to investigate whether adenosine plays a protective role in METH-induced toxicity. METH-induced decrements in neostriatal dopamine content and tyrosine hydroxylase activity in mice were potentiated by concurrent treatment with caffeine, a nonselective adenosine antagonist that blocks both A1 and A2 adenosine receptors. In contrast, chronic treatment of mice with caffeine through their drinking water for 4 weeks, which increased the number of adenosine A1 receptors in the neostriatum and frontal cortex, followed by drug washout, prevented the neurochemical changes produced by the treatment of mice with METH treatment. In contrast, this treatment did not prevent 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine-induced dopaminergic neurotoxicity. Furthermore, concurrent administration of cyclopentyladenosine, an adenosine A1 receptor agonist, attenuated the METH-induced neurochemical changes. This protection by cyclopentyladenosine was blocked by cyclopentyltheophylline, an A1 receptor antagonist. These results indicate that activation of A1 receptors can protect against METH-induced neurotoxicity in mice.

  18. Ethanol-induced increase in portal blood flow: Role of acetate and A1- and A2-adenosine receptors

    International Nuclear Information System (INIS)

    Carmichael, F.J.; Saldivia, V.; Varghese, G.A.; Israel, Y.; Orrego, H.

    1988-01-01

    The increase in portal blood flow induced by ethanol appears to be adenosine mediated. Acetate, which is released by the liver during ethanol metabolism, is known to increase adenosine levels in tissues and in blood. The effects of acetate on portal blood flow were investigated in rats using the microsphere technique. The intravenous infusion of acetate resulted in vasodilation of the preportal vasculature and in a dose-dependent increase in portal blood flow. This acetate-induced increase in portal blood flow was suppressed by the adenosine receptor blocker, 8-phenyltheophylline. Using the A 1 -adenosine receptor agonist N-6-cyclohexyl adenosine and the A 2 -agonist 5'-N-ethylcarboxamido adenosine, we demonstrate that the effect of adenosine on the preportal vasculature is mediated by the A 2 -subtype of adenosine receptors. In conclusion, these data support the hypothesis that the increase in portal blood flow after ethanol administration results from a preportal vasodilatory effect of adenosine formed from acetate metabolism in extrahepatic tissues

  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

    , it was found that 58% of PANC-1 cells responded to adenosine, whereas only 9% of CFPAC-1 cells responded. Adenosine elicited Ca(2+) signals only in a few rat and human duct cells, which did not seem to correlate with Cl(-) signals. A(2A) receptors were localized in the luminal membranes of rat pancreatic ducts......, plasma membrane of many PANC-1 cells, but only a few CFPAC-1 cells. Taken together, our data indicate that A(2A) receptors open Cl(-) channels in pancreatic ducts cells with functional CFTR. We propose that adenosine can stimulate pancreatic secretion and, thereby, is an active player in the acini...

  20. The role of glial adenosine receptors in neural resilience and the neurobiology of mood disorders

    NARCIS (Netherlands)

    Calker, D; Biber, K

    2005-01-01

    Adenosine receptors were classified into A(1)- and A(2)-receptors in the laboratory of Bernd Hamprecht more than 25 years ago. Adenosine receptors are instrumental to the neurotrophic effects of glia cells. Both microglia and astrocytes release after stimulation via adenosine receptors factors that

  1. Synthesis of disodium [benzene-U-{sup 14}C]-(4-chlorophenylthio)methylenediphosphonate, [benzene-U-{sup 14}C]-tiludronate

    Energy Technology Data Exchange (ETDEWEB)

    Burgos, Alain; Ellames, G.J. [Alnwick Research Centre (United Kingdom). Dept. of Metabolism and Pharmacokinetics

    1995-12-31

    Disodium [benzene-U-{sup 14}C]-(4-chlorophenylithio)methylenediphosphonate, [benzene-{sup 14}C]-Tiludronate, 2, has been prepared in six steps from [benzene-U-{sup 14}C]-acetanilide in an overall radiochemical yield of 41%. A key step in this transformation was the efficient conversion of [U-{sup 14}C]-4-chloroaniline to [benzene-U-{sup 14}C]-4-chlorophenylthiocyanate, 5, in 83% yield by treatment of the corresponding diazonium salt, 9 with iron(111) thiocyanate. It should be noted that formation of the isomeric [benzene-U-{sup 14}C]-4-chlorophenylisothiocyanate, 11, as a byproduct, was observed in only {approx} 1% yield. (author).

  2. 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.

  3. Effects of adenosine on pressure-flow relationships in an in vitro model of compartment syndrome.

    Science.gov (United States)

    Shrier, I; Baratz, A; Magder, S

    1997-03-01

    Blood flow through skeletal muscle is best modeled with a vascular waterfall at the arteriolar level. Under these conditions, flow is determined by the difference between perfusion pressure (Pper) and the waterfall pressure (Pcrit), divided by the arterial resistance (Ra). By pump perfusing an isolated canine gastrocnemius muscle (n = 6) after it was placed within an airtight box, with and without adenosine infusion, we observed an interaction between the pressure surrounding a muscle (as occurs in compartment syndrome) and baseline vascular tone. We titrated adenosine concentration to double baseline flow. We measured Pcrit and Ra at box pressures (Pbox), which resulted in 100 (Pbox = 0), 90, 75, and 50% flow without adenosine; and 200, 180, 150, 100, and 50% flow with adenosine. Without adenosine, each 10% decline in flow was associated with a 5.7 mmHg increase in Pcrit (P 0.9). We conclude that increases in pressure surrounding a muscle limit flow primarily through changes in Pcrit with and without adenosine-induced vasodilation. The interaction between Pbox and adenosine with respect to Pcrit but not Ra suggests that Pbox affects the tone of the vessels responsible for Pcrit but not Ra.

  4. Adenosine Inhibits the Excitatory Synaptic Inputs to Basal Forebrain Cholinergic, GABAergic and Parvalbumin Neurons in mice

    Directory of Open Access Journals (Sweden)

    Chun eYang

    2013-06-01

    Full Text Available Coffee and tea contain the stimulants caffeine and theophylline. These compounds act as antagonists of adenosine receptors. Adenosine promotes sleep and its extracellular concentration rises in association with prolonged wakefulness, particularly in the basal forebrain (BF region involved in activating the cerebral cortex. However, the effect of adenosine on identified BF neurons, especially non-cholinergic neurons, is incompletely understood. Here we used whole-cell patch-clamp recordings in mouse brain slices prepared from two validated transgenic mouse lines with fluorescent proteins expressed in GABAergic or parvalbumin (PV neurons to determine the effect of adenosine. Whole-cell recordings were made BF cholinergic neurons and from BF GABAergic & PV neurons with the size (>20 µm and intrinsic membrane properties (prominent H-currents corresponding to cortically projecting neurons. A brief (2 min bath application of adenosine (100 μM decreased the frequency but not the amplitude of spontaneous excitatory postsynaptic currents in all groups of BF cholinergic, GABAergic and PV neurons we recorded. In addition, adenosine decreased the frequency of miniature EPSCs in BF cholinergic neurons. Adenosine had no effect on the frequency of spontaneous inhibitory postsynaptic currents in cholinergic neurons or GABAergic neurons with large H-currents but reduced them in a group of GABAergic neurons with smaller H-currents. All effects of adenosine were blocked by a selective, adenosine A1 receptor antagonist, cyclopentyltheophylline (CPT, 1 μM. Adenosine had no postsynaptic effects. Taken together, our work suggests that adenosine promotes sleep by an A1-receptor mediated inhibition of glutamatergic inputs to cortically-projecting cholinergic and GABA/PV neurons. Conversely, caffeine and theophylline promote attentive wakefulness by inhibiting these A1 receptors in BF thereby promoting the high-frequency oscillations in the cortex required for

  5. Transient Delivery of Adenosine as a Novel Therapy to Prevent Epileptogenesis

    Science.gov (United States)

    2015-10-01

    Chemother 6:98–101. Bukoski RD, Sparks HV, and Mela -Riker LM (1986) A role for mitochondria in myocardial adenosine production. Adv Exp Med Biol 194:157–167...Bukoski RD, Sparks HV, and Mela LM (1983) Rat heart mitochondria release adenosine. Biochem Biophys Res Commun 113:990–995. Burnstock G, Fredholm BB

  6. A quantitative assay for lysosomal acidification rates in human osteoclasts

    DEFF Research Database (Denmark)

    Jensen, Vicki Kaiser; Nosjean, Olivier; Dziegiel, Morten Hanefeld

    2011-01-01

    The osteoclast initiates resorption by creating a resorption lacuna. The ruffled border surrounding the lacunae arises from exocytosis of lysosomes. To dissolve the inorganic phase of the bone, the vacuolar adenosine triphosphatase, located in the ruffled border, pumps protons into the resorption...... assay with respect to lysosomal acidification and assess whether it is a reliable test of a compound's ability to inhibit acidification. Investigated were the expression levels of the lysosomal acidification machinery, the activation of the assay by adenosine triphosphate, H(+) and Cl(-) dependency...

  7. Estimation of the rate of energy production of rat mast cells in vitro

    DEFF Research Database (Denmark)

    Johansen, Torben

    1983-01-01

    Rat mast cells were treated with glycolytic and respiratory inhibitors. The rate of adenosine triphosphate depletion of cells incubated with both types of inhibitors and the rate of lactate produced in presence of antimycin A and glucose were used to estimate the rate of oxidative and glycolytic...

  8. Heavy Metals, Cardiovascular Disease, and the Unexpected Benefits of Edetate Disodium Chelation Therapy

    Science.gov (United States)

    Lamas, Gervasio A.; Navas-Acien, Ana; Mark, Daniel B.; Lee, Kerry L.

    2016-01-01

    This review summarizes evidence from 2 lines of research previously thought unrelated: the unexpectedly positive results of the Trial to Assess Chelation Therapy (TACT), and a body of epidemiological data showing that accumulation of biologically active metals, such as lead and cadmium, is an important risk factor for cardiovascular disease. Considering these 2 areas of work together may lead to the identification of new, modifiable risk factors for atherosclerotic cardiovascular disease. We examine the history of chelation up through the report of TACT. We then describe work connecting higher metal levels in the body with the future risk of cardiovascular disease. We conclude by presenting a brief overview of a newly planned National Institutes of Health trial, TACT2, in which we will attempt to replicate the findings of TACT and to establish that removal of toxic metal stores from the body is a plausible mechanistic explanation for the benefits of edetate disodium treatment. PMID:27199065

  9. A Simple and Rapid Determination of ATP, ADP and AMP Concentrations in Pericarp Tissue of Litchi Fruit by High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Weibo Jiang

    2006-01-01

    Full Text Available A simple and rapid method using high performance liquid chromatography (HPLC was developed to determine levels of adenosine triphosphate (ATP, adenosine diphosphate (ADP and adenosine monophosphate (AMP in litchi fruit pericarp tissue. This HPLC method used acetonitrile gradient elution and shortened the time required for determinations of adenosine phosphates. This analysis exhibited good repeatability (coefficients of variation 1.28–1.80 % and recovery rate (94.7–97.1 %. The correlation coefficients of ATP, ADP and AMP with their peak areas at a range of 0–80 ng were 0.9946, 0.9994 and 0.9974, respectively. This method was applied to determine levels of adenosine phosphates in pericarp tissue of litchi fruit at harvest. There were 27.4 μg/g of ATP, 35.4 μg/g of ADP and 7.9 μg/g of AMP on a fresh mass basis.

  10. 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

    2012-01-04

    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.

  11. DNA sensor cGAS-mediated immune recognition

    Directory of Open Access Journals (Sweden)

    Pengyan Xia

    2016-09-01

    Full Text Available Abstract The host takes use of pattern recognition receptors (PRRs to defend against pathogen invasion or cellular damage. Among microorganism-associated molecular patterns detected by host PRRs, nucleic acids derived from bacteria or viruses are tightly supervised, providing a fundamental mechanism of host defense. Pathogenic DNAs are supposed to be detected by DNA sensors that induce the activation of NFκB or TBK1-IRF3 pathway. DNA sensor cGAS is widely expressed in innate immune cells and is a key sensor of invading DNAs in several cell types. cGAS binds to DNA, followed by a conformational change that allows the synthesis of cyclic guanosine monophosphate–adenosine monophosphate (cGAMP from adenosine triphosphate and guanosine triphosphate. cGAMP is a strong activator of STING that can activate IRF3 and subsequent type I interferon production. Here we describe recent progresses in DNA sensors especially cGAS in the innate immune responses against pathogenic DNAs.

  12. Optimisation of ATP determination in drinking water

    DEFF Research Database (Denmark)

    Corfitzen, Charlotte B.; Albrechtsen, Hans-Jørgen

    Adenosine Triphosphate (ATP) can be used as a relative measure of cell activity, and is measured by the light output from the reaction between luciferin and ATP catalyzed by firefly luciferase. The measurement has potential as a monitoring and surveillance tool within drinking water distribution,...... be separated from the water phase by filtration.......Adenosine Triphosphate (ATP) can be used as a relative measure of cell activity, and is measured by the light output from the reaction between luciferin and ATP catalyzed by firefly luciferase. The measurement has potential as a monitoring and surveillance tool within drinking water distribution...... and an Advance Coupe luminometer. The investigations showed a 60 times higher response of the PCP-kit, making it more suitable for measurement of samples with low ATP content. ATP-standard dilutions prepared in tap water were stable for at least 15 months when stored frozen at -80ºC, and storage of large...

  13. Creatine phosphate disodium salt protects against Dox-induced cardiotoxicity by increasing calumenin.

    Science.gov (United States)

    Wang, Yu; Sun, Ying; Guo, Xin; Fu, Yao; Long, Jie; Wei, Cheng-Xi; Zhao, Ming

    2018-06-01

    Inhibiting endoplasmic reticulum stress (ERS)-induced apoptosis may be a new therapeutic target in cardiovascular diseases. Creatine phosphate disodium salt (CP) has been reported to have cardiovascular protective effect, but its effects on ERS are unknown. The aim of this study was to identify the mechanism by which CP exerts its cardioprotection in doxorubicin (Dox)-induced cardiomyocytes injury. In our study, neonatal rats cardiomyocytes (NRC) was randomly divided into control group, model group, and treatment group. The cell viability and apoptosis were detected. grp78, grp94, and calumenin of the each group were monitored. To investigate the role of calumenin, Dox-induced ERS was compared in control and down-regulated calumenin cardiomyocytes. Our results showed that CP decreased Dox-induced apoptosis and relieved ERS. We found calumenin increased in Dox-induced apoptosis with CP. ERS effector C/EBP homologous protein was down-regulated by CP and it was influenced by calumenin. CP could protect NRC by inhibiting ERS, this mechanisms may be associated with its increasing of calumenin.

  14. Effects of adenosine on the organ injury and dysfunction caused by hemorrhagic shock

    International Nuclear Information System (INIS)

    Soliman, M.M.

    2009-01-01

    Objectives: Adenosine has been shown in animal and human studies to decrease the post-ischemic myocardial injury by lowering the levels of tumor necrosis factor-a. The objectives of the study was to examine the protective effects of adenosine on the organ injury (liver, kidney, pancreas) associated with hemorrhagic shock in rats. Methodology: The study was conducted at Cardiovascular Physiology laboratory, King Saud University, Riyadh in 2007-2008. Anesthetized male Sprague- Dawley rats were assigned to hemorrhage and resuscitation treated with 20mM adenosine , untreated, or similar time matched control groups (n=6 per group). Rats were hemorrhaged for one hour using a reservoir model. Arterial blood pressure was monitored for one hour, and maintained at a mean arterial blood pressure of 40 mmHg. Adenosine 20mM was injected intra-arterially, before resuscitation in the adenosine treated group. Resuscitation was performed by re infusion of the sheded blood for 30 minutes. Arterial blood samples were analyzed for biochemical indicators of multiple organ injury: 1) liver function: aspartate aminotransferase (AST), alanine aminotransferase (ALT), 2) renal function: urea and creatinine, 3) pancreatic function: amylase. Results: In the control group there was no significant rise in the serum levels of (i) urea and creatinine, (ii) aspartate aminotransferase (AST) and alanine aminotransferase (ALT), (iii) amylase. While in the adenosine treated group, resuscitation from one hour of hemorrhagic shock resulted in significant rises in the serum levels of (i) urea and creatinine, (ii) aspartate aminotransferase (AST) and alanine aminotransferase (ALT), (iii) amylase. Treatment of rats with 20mM adenosine before resuscitation following one hour of hemorrhagic shock decreased the multiple organ injury and dysfunction caused by hemorrhagic shock. Conclusion: Adenosine attenuated the renal, liver and pancreatic injury caused by hemorrhagic shock and resuscitation in rats. Thus

  15. Adenosine Receptor Stimulation Improves Glucocorticoid-Induced Osteoporosis in a Rat Model

    Directory of Open Access Journals (Sweden)

    Gabriele Pizzino

    2017-09-01

    Full Text Available Glucocorticoid-induced osteoporosis (GIO is a secondary cause of bone loss. Bisphosphonates approved for GIO, might induce jaw osteonecrosis; thus additional therapeutics are required. Adenosine receptor agonists are positive regulators of bone remodeling, thus the efficacy of adenosine receptor stimulation for treating GIO was tested. In a preventive study GIO was induced in Sprague-Dawley rats by methylprednisolone (MP for 60 days. Animals were randomly assigned to receive polydeoxyribonucleotide (PDRN, an adenosine A2 receptor agonist, or PDRN and DMPX (3,7-dimethyl-1-propargylxanthine, an A2 antagonist, or vehicle (0.9% NaCl. Another set of animals was used for a treatment study, following the 60 days of MP-induction rats were randomized to receive (for additional 60 days PDRN, or PDRN and DMPX (an adenosine A2 receptor antagonist, or zoledronate (as control for gold standard treatment, or vehicle. Control animals were administered with vehicle for either 60 or 120 days. Femurs were analyzed after treatments for histology, imaging, and breaking strength analysis. MP treatment induced severe bone loss, the concomitant use of PDRN prevented the developing of osteoporosis. In rats treated for 120 days, PDRN restored bone architecture and bone strength; increased b-ALP, osteocalcin, osteoprotegerin and stimulated the Wnt canonical and non-canonical pathway. Zoledronate reduced bone resorption and ameliorated the histological features, without significant effects on bone formation. Our results suggest that adenosine receptor stimulation might be useful for preventing and treating GIO.

  16. 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.

  17. Adenosine deaminase organic effect in normal and abnormal cerebrospinal fluid

    International Nuclear Information System (INIS)

    Hamad, A.M.; Samarai, M.A.

    2007-01-01

    To study the effect of the organic substances on adenosine deaminase (ADA) activity in normal and abnormal cerebrospinal fluid (CSF). Various concentrations of 2-mercaptopurine, Ame-tycine, Adenosine analogues (Guanine, Thymine) and ATP were tested to see their effect on ADA activity in normal and abnormal CSF. ADA activity in normal and abnormal CSF was remarkably decreased with the increasing of concentrations of substances tested. These effects may have important therapeutic implications. (author)

  18. Synthesis and study of the triphosphate salt LiSr2P3O10·8H2O

    International Nuclear Information System (INIS)

    Sotnikova-Yuzhik, V.A.; Peslyak, G.V.

    1995-01-01

    Lithium triphosphate interaction with strontium nitrate in aqueous solution at 0.3 mole% concentration and 20 deg C is studied. Formation of crystal hydrate LiSr 2 P 3 O 10 ·8H 2 O and amorphous phase of variable composition Li 2,5-0,5x P 3 O 10 ·6H 2 O (0.20≤x≤0.55) is determined. Data on the stability of binary lithium-strontium triphosphate at storage, sequence of chemical and phase transitions under heating are obtained. 5 refs., 4 figs., 3 tabs

  19. Analysis of larger than tetrameric poly(adenosine diphosphoribose) by a radioimmunoassay in nuclei separated in organic solvents

    International Nuclear Information System (INIS)

    Ferro, A.M.; Minaga, T.; Piper, W.N.; Kun, E.

    1978-01-01

    Antibodies were prepared against poly(adenosine diphosphoribose) of an average chain length of 40 adenosine diphosphoribose units by repeated injection of the polymer mixed with methylated albumin and adjuvants into rabbits. The antibody was present mainly in the 7 S fraction of the immunoglobulins. A membrane binding assay was developed, and its specificity determined for the detection of (adenosine diphosphoribose) (n>4) in organs. The method is suitable for the study of the variation of the polymer content of nuclei. The size recognition of the anti-poly(adenosine diphosphoribose) globulin fraction was the same for polymers composed of 4-40 adenosine diphosphoribose units, but smaller oligomers were not detectible. A quantitative extraction technique was developed and applied for radioimmunoassay of nuclear (adenosine diphosphoribose) n>4. Organs were freeze-clamped, freeze dried, broken into subcellular fragments in a colloid mill, and the nuclear fraction was subsequently separated in organic solvents in order to preserve the polymer. Nicotinamide and nicotinic acid, when administered in vivo, augmented the (adenosine diphosphoribose) (n>4) content of rat liver and heart. Tissues of infant pigeons contained larger quantities of (adenosine diphosphoribose) (n>4) than tissues of adult rates. (Auth.)

  20. Metabolic Recruitment and Directed Evolution of Nucleoside Triphosphate Uptake in Escherichia coli.

    Science.gov (United States)

    Pezo, Valérie; Hassan, Camille; Louis, Dominique; Sargueil, Bruno; Herdewijn, Piet; Marlière, Philippe

    2018-05-18

    We report the design and elaboration of a selection protocol for importing a canonical substrate of DNA polymerase, thymidine triphosphate (dTTP) in Escherichia coli. Bacterial strains whose growth depend on dTTP uptake, through the action of an algal plastid transporter expressed from a synthetic gene inserted in the chromosome, were constructed and shown to withstand the simultaneous loss of thymidylate synthase and thymidine kinase. Such thyA tdk dual deletant strains provide an experimental model of tight nutritional containment for preventing dissemination of microbial GMOs. Our strains transported the four canonical dNTPs, in the following order of preference: dCTP > dATP ≥ dGTP > dTTP. Prolonged cultivation under limitation of exogenous dTTP led to the enhancement of dNTP transport by adaptive evolution. We investigated the uptake of dCTP analogues with altered sugar or nucleobase moieties, which were found to cause a loss of cell viability and an increase of mutant frequency, respectively. E. coli strains equipped with nucleoside triphosphate transporters should be instrumental for evolving organisms whose DNA genome is morphed chemically by fully substituting its canonical nucleotide components.

  1. An Analysis of Responses to Defibrotide in the Pulmonary Vascular Bed of the Cat.

    Science.gov (United States)

    Kaye, Alan D; Skonieczny, Brendan D; Kaye, Aaron J; Harris, Zoey I; Luk, Eric J

    2016-01-01

    Defibrotide is a polydisperse mixture of single-stranded oligonucleotides with many pharmacologic properties and multiple actions on the vascular endothelium. Responses to defibrotide and other vasodepressor agents were evaluated in the pulmonary vascular bed of the cat under conditions of controlled pulmonary blood flow and constant left atrial pressure. Lobar arterial pressure was increased to a high steady level with the thromboxane A2 analog U-46619. Under increased-tone conditions, defibrotide caused dose-dependent decreases in lobar arterial pressure without altering systemic arterial and left atrial pressures. Responses to defibrotide were significantly attenuated after the administration of the cyclooxygenase inhibitor sodium meclofenamate. Responses to defibrotide were also significantly attenuated after the administration of both the adenosine 1 and 2 receptor antagonists 8-cyclopentyl-1,3-dimethylxanthine and 8-(3-chlorostyryl)caffeine. Responses to defibrotide were not altered after the administration of the vascular selective adenosine triphosphate-sensitive potassium channel blocker U-37883A, or after the administration of the nitric oxide synthase inhibitor L-N-(1-iminoethyl)-ornithine. These data show that defibrotide has significant vasodepressor activity in the pulmonary vascular bed of the cat. They also suggest that pulmonary vasodilator responses to defibrotide are partially dependent on both the activation of the cyclooxygenase enzyme and adenosine 1 and 2 receptor pathways and independent of the activation of adenosine triphosphate-sensitive potassium channels or the synthesis of nitric oxide in the pulmonary vascular bed of the cat.

  2. Modulation of short-term social memory in rats by adenosine A1 and A(2A) receptors.

    Science.gov (United States)

    Prediger, Rui D S; Takahashi, Reinaldo N

    2005-03-16

    The recognition of an unfamiliar juvenile rat by an adult rat has been shown to imply short-term memory processes. The present study was designed to examine the role of adenosine receptors in the short-term social memory of rats using the social recognition paradigm. Adenosine (5.0-10.0 mg/kg), the selective adenosine A1 receptor agonist 2-chloro-N6-cyclopentyladenosine (CCPA, 0.025-0.05 mg/kg) and the selective adenosine A(2A) receptor agonist N6-[2-(3,5-dimethoxyphenyl)-2-(2-methylphenyl)ethyl]adenosine (DPMA, 1.0-5.0 mg/kg), given by i.p. route 30 min before the test, disrupted the juvenile recognition ability of adult rats. This negative effect of adenosine (5.0 mg/kg, i.p.) on social memory was prevented by pretreatment with the non-selective adenosine receptor antagonist caffeine (10.0 mg/kg, i.p.), the adenosine A1 antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, 1.0 mg/kg, i.p.) and the adenosine A(2A) antagonist 4-(2-[7-amino-2-{2-furyl}{1,2,4}triazolo-{2,3-a}{1,3,5}triazin-5-yl-amino]ethyl)phenol (ZM241385, 1.0 mg/kg, i.p.). Furthermore, acute administration of caffeine (10.0-30.0 mg/kg, i.p.), DPCPX (1.0-3.0 mg/kg, i.p.) or ZM241385 (0.5-1.0 mg/kg, i.p.) improved the short-term social memory in a specific manner. These results indicate that adenosine modulates the short-term social memory in rats by acting on both A1 and A(2A) receptors, with adenosine receptor agonists and antagonists, respectively, disrupting and enhancing the social memory.

  3. Conidiation of Neurospora crassa induced by treatment with natrium fluoride in submerged culture

    Energy Technology Data Exchange (ETDEWEB)

    Timberlake, W E; Turian, G

    1975-01-01

    A transient treatment of pregerminated conidia of Neurospora crassa with NaF induced young, submerged cultures to prematurely differentiate conidia. The inductive treatment decreased the rate of respiration (with lower RQ), reduced the relative concentration of nucleoside triphosphates, and inhibited leucine incorporation into protein and adenosine incorporation into RNA.

  4. Visualization of ATP release in pancreatic acini in response to cholinergic stimulus. Use of fluorescent probes and confocal microscopy

    DEFF Research Database (Denmark)

    Sørensen, Christiane Elisabeth; Novak, Ivana

    2001-01-01

    of this reaction in confocal microscopy, we monitored luciferin fluorescence as a sign of ATP release by single acini. In addition we used quinacrine to mark ATP stores, which were similar to those marked with fluorescent ATP, 2'-(or-3')-O-(N-methylanthraniloyl) adenosine 5'-triphosphate, but only partially...

  5. Effect of Inoculating Bradyrhizobium on Phosphorus Use Efficiency ...

    African Journals Online (AJOL)

    3 School of Natural Resources Management and Environmental Sciences, ..... was produced per unit of P applied by un-inoculated, SB6B1 and Legumefix ... meet the high energy costs for adenosine triphosphate (ATP) synthesis .... Kumar and Kairon (1980) also determined an apparent P .... Prentice Hall, New Jersey.

  6. Optimum outlier model for potential improvement of environmental cleaning and disinfection.

    Science.gov (United States)

    Rupp, Mark E; Huerta, Tomas; Cavalieri, R J; Lyden, Elizabeth; Van Schooneveld, Trevor; Carling, Philip; Smith, Philip W

    2014-06-01

    The effectiveness and efficiency of 17 housekeepers in terminal cleaning 292 hospital rooms was evaluated through adenosine triphosphate detection. A subgroup of housekeepers was identified who were significantly more effective and efficient than their coworkers. These optimum outliers may be used in performance improvement to optimize environmental cleaning.

  7. Investigations into the origin of the molecular recognition of several adenosine deaminase inhibitors.

    Science.gov (United States)

    Gillerman, Irina; Fischer, Bilha

    2011-01-13

    Inhibitors of adenosine deaminase (ADA, EC 3.5.4.4) are potential therapeutic agents for the treatment of various health disorders. Several highly potent inhibitors were previously identified, yet they exhibit unacceptable toxicities. We performed a SAR study involving a series of C2 or C8 substituted purine-riboside analogues with a view to discover less potent inhibitors with a lesser toxicity. We found that any substitution at C8 position of nebularine resulted in total loss of activity toward calf intestinal ADA. However, several 2-substituted-adenosine, 8-aza-adenosine, and nebularine analogues exhibited inhibitory activity. Specifically, 2-Cl-purine riboside, 8-aza-2-thiohexyl adenosine, 2-thiohexyl adenosine, and 2-MeS-purine riboside were found to be competitive inhibitors of ADA with K(i) values of 25, 22, 6, and 3 μM, respectively. We concluded that electronic parameters are not major recognition determinants of ADA but rather steric parameters. A C2 substituent which fits ADA hydrophobic pocket and improves H-bonding with the enzyme makes a good inhibitor. In addition, a gg rotamer about C4'-C5' bond is apparently an important recognition determinant.

  8. Emerging therapies for the management of decompensated heart failure: from bench to bedside.

    Science.gov (United States)

    deGoma, Emil M; Vagelos, Randall H; Fowler, Michael B; Ashley, Euan A

    2006-12-19

    While pharmaceutical innovation has been highly successful in reducing mortality in chronic heart failure, this has not been matched by similar success in decompensated heart failure syndromes. Despite outstanding issues over definitions and end points, we argue in this paper that an unprecedented wealth of pharmacologic innovation may soon transform the management of these challenging patients. Agents that target contractility, such as cardiac myosin activators and novel adenosine triphosphate-dependent transmembrane sodium-potassium pump inhibitors, provide inotropic support without arrhythmogenic increases in cytosolic calcium or side effects of more traditional agents. Adenosine receptor blockade may improve glomerular filtration and diuresis by exerting a direct beneficial effect on glomerular blood flow while vasopressin antagonists promote free water excretion without compromising renal function and may simultaneously inhibit myocardial remodeling. Urodilatin, the renally synthesized isoform of atrial natriuretic peptide, may improve pulmonary congestion via vasodilation and enhanced diuresis. Finally, metabolic modulators such as perhexiline may optimize myocardial energy utilization by shifting adenosine triphosphate production from free fatty acids to glucose, a unique and conceptually appealing approach to the management of heart failure. These advances allow optimism not only for the advancement of our understanding and management of decompensated heart failure syndromes but for the translational research effort in heart failure biology in general.

  9. 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

    of 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...... was abolished by IAA-94. Furthermore, the vasoconstriction caused by adenosine was significantly inhibited by 5 microM nifedipine (control 8.3 +/- 0.2 microM, ado 3.6 +/- 0.6 microM, ado + nifedipine 6.8 +/- 0.2 microM) suggesting involvement of voltage-dependent calcium channels. CONCLUSION: We conclude...

  10. Dynamic 31P-MR-spectroscopy of the quadriceps muscle. Influence of sex and age on spectroscopic results

    International Nuclear Information System (INIS)

    Schunk, K.; Romaneehsen, B.; Kessler, S.; Schadmand-Fischer, S.; Thelen, M.

    1999-01-01

    Purpose: 31 P-MRS is used to assess the influence of sex and age on quadriceps muscle metabolism before and after exercise. Materials and Methods: 32 healthy volunteers (15 women, 17 men; mean age: 38±17 yrs.) were examined by dynamic phosphorus-31 ( 31 P) magnetic resonance spectroscopy (MRS). In the magnet, the quadriceps muscle was stressed by an isometric and an isotonic form of exercise until exhaustion, respectively. Results: Resting conditions: With increasing subjects' age, the ratio β-adenosine triphosphate/total phosphate decreased (r=-0.37; p=0.02). With increasing subjects' age, the ratios inorganic phosphate/phosphocreatine (r=0.79; p=5x10 -8 ), phosphomonoester/β-adenosine triphosphate (r=0.74; p=10 -6 ) and phosphodiester/β-adenosine triphosphate (r=0.62; p=10 -4 ) increased. The pH was the only one of the evaluated spectroscopic parameters which showed a sex-dependence: Female subjects had a significantly lower pH (7.03±0.02) than male subjects (7.05±0.03; p=0,01). Exercise: With increasing age, the maxima of inorganic phosphate/phosphocreatine were less extreme during both of the exercises (r=-0.42; p=0.0005). Likewise, the exercise-induced acidosis was less severe with increasing age (r=0.53; p=6x10 -6 ). After the end of the exercise, the times of half recovery of inorganic phosphate/phosphocreatine and the pH correlated neither with the subjects' age nor with sex or cross-sectional area of the quadriceps muscle. Conclusion: Sex and age of volunteers affect spectroscopic results. This influence has to be considered in the interpretation of spectroscopic studies. (orig.) [de

  11. Effectiveness of current disinfection procedures against biofilm on contaminated GI endoscopes.

    Science.gov (United States)

    Neves, Marcelo S; da Silva, Marlei Gomes; Ventura, Grasiella M; Côrtes, Patrícia Barbur; Duarte, Rafael Silva; de Souza, Heitor S

    2016-05-01

    Attention to patient safety has increased recently due to outbreaks of nosocomial infections associated with GI endoscopy. The aim of this study was to evaluate current cleaning and disinfection procedures of endoscope channels with high bioburden and biofilm analysis, including the use of resistant mycobacteria associated with postsurgical infections in Brazil. Twenty-seven original endoscope channels were contaminated with organic soil containing 10(8) colony-forming units/mL of Pseudomonas aeruginosa, Staphylococcus aureus, or Mycobacterium abscessus subsp bolletii. Biofilms with the same microorganisms were developed on the inner surface of channels with the initial inoculum of 10(5) colony-forming units/mL. Channels were reprocessed following current protocol, and samples from cleaning and disinfection steps were analyzed by bioluminescence for adenosine triphosphate, cultures for viable microorganisms, and confocal microscopy. After contamination, adenosine triphosphate levels increased dramatically, and high bacterial growth was observed in all cultures. After cleaning, adenosine triphosphate levels decreased to values comparable to precontamination levels, and bacterial growth was demonstrated in 5 of 27 catheters, 2 with P aeruginosa and 3 with M abscessus. With regard to induced biofilm, a remarkable reduction occurred after cleaning, but significant microbial growth inhibition occurred only after disinfection. Nevertheless, viable microorganisms within the biofilm were still detected by confocal microscopy, more so with glutaraldehyde than with peracetic acid or O-phataladehyde. After the complete disinfection procedure, viable microorganisms could still be detected within the biofilm on endoscope channels. Prevention of biofilm development within endoscope channels should be a priority in disinfection procedures, particularly for ERCP and EUS. Copyright © 2016 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights

  12. Effects of targeted deletion of A1 adenosine receptors on postischemic cardiac function and expression of adenosine receptor subtypes.

    Science.gov (United States)

    Morrison, R Ray; Teng, Bunyen; Oldenburg, Peter J; Katwa, Laxmansa C; Schnermann, Jurgen B; Mustafa, S Jamal

    2006-10-01

    To examine ischemic tolerance in the absence of A(1) adenosine receptors (A(1)ARs), isolated wild-type (WT) and A(1)AR knockout (A(1)KO) murine hearts underwent global ischemia-reperfusion, and injury was measured in terms of functional recovery and efflux of lactate dehydrogenase (LDH). Hearts were analyzed by real-time RT-PCR both at baseline and at intervals during ischemia-reperfusion to determine whether compensatory expression of other adenosine receptor subtypes occurs with either A(1)AR deletion and/or ischemia-reperfusion. A(1)KO hearts had higher baseline coronary flow (CF) and left ventricular developed pressure (LVDP) than WT hearts, whereas heart rate was unchanged by A(1)AR deletion. After 20 min of ischemia, CF was attenuated in A(1)KO compared with WT hearts, and this reduction persisted throughout reperfusion. Final recovery of LVDP was decreased in A(1)KO hearts (54.4 +/- 5.1 vs. WT 81.1 +/- 3.4% preischemic baseline) and correlated with higher diastolic pressure during reperfusion. Postischemic efflux of LDH was greater in A(1)KO compared with WT hearts. Real-time RT-PCR demonstrated the absence of A(1)AR transcript in A(1)KO hearts, and the message for A(2A), A(2B), and A(3) adenosine receptors was similar in uninstrumented A(1)KO and WT hearts. Ischemia-reperfusion increased A(2B) mRNA expression 2.5-fold in both WT and A(1)KO hearts without changing A(1) or A(3) expression. In WT hearts, ischemia transiently doubled A(2A) mRNA, which returned to preischemic level upon reperfusion, a pattern not observed in A(1)KO hearts. Together, these data affirm the cardioprotective role of A(1)ARs and suggest that induced expression of other adenosine receptor subtypes may participate in the response to ischemia-reperfusion in isolated murine hearts.

  13. Aberrant Bone Density in Aging Mice Lacking the Adenosine Transporter ENT1

    Science.gov (United States)

    Hinton, David J.; McGee-Lawrence, Meghan E.; Lee, Moonnoh R.; Kwong, Hoi K.; Westendorf, Jennifer J.; Choi, Doo-Sup

    2014-01-01

    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. PMID:24586402

  14. 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.

  15. Ability of γδ T cells to modulate the Foxp3 T cell response is dependent on adenosine.

    Directory of Open Access Journals (Sweden)

    Dongchun Liang

    Full Text Available Whether γδ T cells inhibit or enhance the Foxp3 T cell response depends upon their activation status. The critical enhancing effector in the supernatant is adenosine. Activated γδ T cells express adenosine receptors at high levels, which enables them to deprive Foxp3+ T cells of adenosine, and to inhibit their expansion. Meanwhile, cell-free supernatants of γδ T cell cultures enhance Foxp3 T cell expansion. Thus, inhibition and enhancement by γδ T cells of Foxp3 T cell response are a reflection of the balance between adenosine production and absorption by γδ T cells. Non-activated γδ T cells produce adenosine but bind little, and thus enhance the Foxp3 T cell response. Activated γδ T cells express high density of adenosine receptors and have a greatly increased ability to bind adenosine. Extracellular adenosine metabolism and expression of adenosine receptor A2ARs by γδ T cells played a major role in the outcome of γδ and Foxp3 T cell interactions. A better understanding of the functional conversion of γδ T cells could lead to γδ T cell-targeted immunotherapies for related diseases.

  16. Differences in activity of cytochrome C oxidase in brain between sleep and wakefulness.

    Science.gov (United States)

    Nikonova, Elena V; Vijayasarathy, Camasamudram; Zhang, Lin; Cater, Jacqueline R; Galante, Raymond J; Ward, Stephen E; Avadhani, Narayan G; Pack, Allan I

    2005-01-01

    Increased mRNA level of subunit 1 cytochrome c oxidase (COXI) during wakefulness and after short-term sleep deprivation has been described in brain. We hypothesized that this might contribute to increased activity of cytochrome oxidase (COX) enzyme during wakefulness, as part of the mechanisms to provide sufficient amounts of adenosine triphosphate to meet increased neuronal energy demands. COX activity was measured in isolated mitochondria from different brain regions in groups of rats with 3 hours of spontaneous sleep, 3 hours of spontaneous wake, and 3 hours of sleep deprivation. The group with 3 hours of spontaneous wake was added to delineate the circadian component of changes in the enzyme activity. Northern blot analysis was performed to examine the mRNA levels of 2 subunits of the enzyme COXI and COXIV, encoded by mitochondrial and nuclear DNA, respectively. Laboratory of Biochemistry, Department of Animal Biology, and Center for Sleep and Respiratory Neurobiology, University of Pennsylvania. 2-month-old male Fischer rats (N = 21) implanted for polygraphic recording. For COX activity, there was a main effect by analysis of variance of experimental group (P sleep-deprived groups as compared to the sleep group. A main effect of brain region was also significant (P sleep. There is an increase in COX activity after both 3 hours of spontaneous wake and 3 hours of sleep deprivation as compared with 3 hours of spontaneous sleep in diverse brain regions, which could be, in part, explained by the increased levels of bigenomic transcripts of the enzyme. This likely contributes to increased adenosine triphosphate production during wakefulness. ADP, adenosine diphosphate; ATP, adenosine triphosphate; COXI, cytochrome c oxidase subunit 1 mRNA; COX, cytochrome c oxidase (protein); CREB, cyclic AMP response element binding protein; DNA, deoxyribonucleic acid; EDTA, ethylenediaminetetraacetic acid; EEG, electroencephalography; EMG, electromyography; GABP, GA binding

  17. Evaluation of usefulness of pleural fluid adenosine deaminase in diagnosing tuberculous pleural effusion from empyema

    Directory of Open Access Journals (Sweden)

    Vijetha Shenoy

    2014-02-01

    Full Text Available Objective: To evaluate the utility of adenosine deaminase activity in the pleural fluid for the diagnosis of tuberculous pleural effusion from empyema of non-tubercular origin. Method: A retrospective analysis of data was performed on patients who were diagnosed to have tuberculous pleural effusion and empyema of non tubercular origin. Among 46 patients at Kasturba Hospital, Manipal University, Manipal, Karnataka, India, from November 201 2 to February 2013 who underwent pleural fluid adenosine deaminase estimation, 25 patients with tuberculous pleural effusion and 21 patients with empyema were diagnosed respectively. Adenosine deaminase in pleural fluid is estimated using colorimetric, Galanti and Guisti method. Results: Pleural fluid Adenosine Deaminase levels among tuberculous pleural effusion(109.38依 53.83 , empyema (141.20依71.69 with P=0.27. Conclusion: Pleural fluid adenosine deaminase alone cannot be used as a marker for the diagnosis of tuberculous pleural effusion.

  18. Adenosine Receptor Heteromers and their Integrative Role in Striatal Function

    Directory of Open Access Journals (Sweden)

    Sergi Ferré

    2007-01-01

    Full Text Available By analyzing the functional role of adenosine receptor heteromers, we review a series of new concepts that should modify our classical views of neurotransmission in the central nervous system (CNS. Neurotransmitter receptors cannot be considered as single functional units anymore. Heteromerization of neurotransmitter receptors confers functional entities that possess different biochemical characteristics with respect to the individual components of the heteromer. Some of these characteristics can be used as a “biochemical fingerprint” to identify neurotransmitter receptor heteromers in the CNS. This is exemplified by changes in binding characteristics that are dependent on coactivation of the receptor units of different adenosine receptor heteromers. Neurotransmitter receptor heteromers can act as “processors” of computations that modulate cell signaling, sometimes critically involved in the control of pre- and postsynaptic neurotransmission. For instance, the adenosine A1-A2A receptor heteromer acts as a concentration-dependent switch that controls striatal glutamatergic neurotransmission. Neurotransmitter receptor heteromers play a particularly important integrative role in the “local module” (the minimal portion of one or more neurons and/or one or more glial cells that operates as an independent integrative unit, where they act as processors mediating computations that convey information from diverse volume-transmitted signals. For instance, the adenosine A2A-dopamine D2 receptor heteromers work as integrators of two different neurotransmitters in the striatal spine module.

  19. A comparison of adenosine and arbutamine for myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Anagnostopoulos, C.; Pennell, D.; Francis, J.; Serup-Hansen, K.; Davies, G.; Underwood, R.

    1998-01-01

    We have compared our standard stress protocol (adenosine combined with exercise) with the new stress agent arbutamine, for thallium-201 myocardial perfusion imaging (MPI) in order to assess the comparative value of arbutamine. We studied 23 patients referred for MPI, and each patient had two studies (18 males, median age 66 years, five with previous myocardial infarction). Uptake scores were assigned to each of nine segments, and the extent and severity of defects were measured using a polar plot. Haemodynamic changes were greater with arbutamine (rate-pressure product increase 78% vs 51%, P = 0.003). Symptoms were experienced by 21 patients with arbutamine and 16 with adenosine (P = 0.07). Agreement between the techniques for classification of patients as normal or as having reversible, fixed or mixed defects was good (19 of 23 studies, 83%, κ = 0.76). Agreement for similar classification of segments was also good (82%, κ = 0.71). Segmental agreement for stress scores was good (86%, κ = 0.77). However, mean size of stress defect was larger with adenosine (83±52 pixels vs 65±48 pixels, P<0.05), though severity and reversibility were similar (P = NS). We conclude that arbutamine provides comparable results to those obtained with adenosine and exercise and that the observed differences are not clinically significant. (orig.)

  20. Circadian rhythm in adenosine A1 receptor of mouse cerebral cortex

    Energy Technology Data Exchange (ETDEWEB)

    Florio, C.; Rosati, A.M.; Traversa, U.; Vertua, R. (Univ. of Trieste (Italy))

    1991-01-01

    In order to investigate diurnal variation in adenosine A1 receptors binding parameters, Bmax and Kd values of specifically bound N6-cyclohexyl-({sup 3}H)adenosine were determined in the cerebral cortex of mice that had been housed under controlled light-dark cycles for 4 weeks. Significant differences were found for Bmax values measured at 3-hr intervals across a 24-h period, with low Bmax values during the light period and high Bmax values during the dark period. The amplitude between 03.00 and 18.00 hr was 33%. No substantial rhythm was found in the Kd values. It is suggested that the changes in the density of A1 receptors could reflect a physiologically-relevant mechanism by which adenosine exerts its modulatory role in the central nervous system.

  1. Circadian rhythm in adenosine A1 receptor of mouse cerebral cortex

    International Nuclear Information System (INIS)

    Florio, C.; Rosati, A.M.; Traversa, U.; Vertua, R.

    1991-01-01

    In order to investigate diurnal variation in adenosine A1 receptors binding parameters, Bmax and Kd values of specifically bound N6-cyclohexyl-[ 3 H]adenosine were determined in the cerebral cortex of mice that had been housed under controlled light-dark cycles for 4 weeks. Significant differences were found for Bmax values measured at 3-hr intervals across a 24-h period, with low Bmax values during the light period and high Bmax values during the dark period. The amplitude between 03.00 and 18.00 hr was 33%. No substantial rhythm was found in the Kd values. It is suggested that the changes in the density of A1 receptors could reflect a physiologically-relevant mechanism by which adenosine exerts its modulatory role in the central nervous system

  2. Antinociceptive effect of purine nucleotides.

    Science.gov (United States)

    Mello, C F; Begnini, J; De-La-Vega, D D; Lopes, F P; Schwartz, C C; Jimenez-Bernal, R E; Bellot, R G; Frussa-Filho, R

    1996-10-01

    The antinociceptive effect of purine nucleotides administered systematically (sc) was determined using the formalin and writhing tests in adult male albino mice. The mechanisms underlying nucleotide-induced antinociception were investigated by preinjecting the animals (sc) with specific antagonists for opioid (naloxone, 1 mg/kg), purinergic P1 (caffeine, 5, 10, of 30 mg/kg); theophylline, 10 mg/kg) or purinergic P2 receptors (suramin, 100 mg/kg; Coomassie blue, 30-300 mg/kg; quinidine, 10 mg/kg). Adenosine, adenosine monophosphate (AMP), diphosphate (ADP) and triphosphate (ATP) caused a reduction in the number of writhes and in the time of licking the formalin-injected paw. Naloxone had no effect on adenosine- or adenine nucleotide-induced antinociception. Caffeine (30 mg/kg) and theophylline (10 mg/kg) reversed the antinociceptive action of adenosine and adenine nucleotide derivatives in both tests. P2 antagonists did not reverse adenine nucleotide-induced antinociception. These results suggest that antinociceptive effect of adenine nucleotides is mediated by adenosine.

  3. Microchannel conductivity measurements in microchip for on line monitoring of dephosphorylation rates of organic phosphates using paramagnetic-beads linked alkaline phosphatase.

    Science.gov (United States)

    Kechadi, Mohammed; Sotta, Bruno; Gamby, Jean

    2015-01-01

    This paper presents the use of polymer coated microelectrodes for the realtime conductivity monitoring in a microchannel photoablated through the polymer without contact. Based on this strategy, a small conductometry sensor has been developed to record in time conductivity variation when an enzymatic reaction occurs through the channel. The rate constant determination, k2, for the dephosphorylation of organic phosphate-alkaline phosphatase-superparamagnetic beads complex using chemically different substrates such as adenosine monoesterphosphate, adenosine diphosphate and adenosine triphosphate was taken as an example to demonstrate selectivity and sensivity of the detection scheme. The k2 value measured for each adenosine phosphate decreases from 39 to 30 s(-1) in proportion with the number (3, 2 and 1) of attached phosphate moiety, thus emphasizing the steric hindrance effect on kinetics. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Small-animal PET study of adenosine A(1) receptors in rat brain: blocking receptors and raising extracellular adenosine.

    Science.gov (United States)

    Paul, Soumen; Khanapur, Shivashankar; Rybczynska, Anna A; Kwizera, Chantal; Sijbesma, Jurgen W A; Ishiwata, Kiichi; Willemsen, Antoon T M; Elsinga, Philip H; Dierckx, Rudi A J O; van Waarde, Aren

    2011-08-01

    Activation of adenosine A(1) receptors (A(1)R) in the brain causes sedation, reduces anxiety, inhibits seizures, and promotes neuroprotection. Cerebral A(1)R can be visualized using 8-dicyclopropylmethyl-1-(11)C-methyl-3-propyl-xanthine ((11)C-MPDX) and PET. This study aims to test whether (11)C-MPDX can be used for quantitative studies of cerebral A(1)R in rodents. (11)C-MPDX was injected (intravenously) into isoflurane-anesthetized male Wistar rats (300 g). A dynamic scan of the central nervous system was obtained, using a small-animal PET camera. A cannula in a femoral artery was used for blood sampling. Three groups of animals were studied: group 1, controls (saline-treated); group 2, animals pretreated with the A(1)R antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, 1 mg, intraperitoneally); and group 3, animals pretreated (intraperitoneally) with a 20% solution of ethanol in saline (2 mL) plus the adenosine kinase inhibitor 4-amino-5-(3-bromophenyl)-7-(6-morpholino-pyridin-3-yl)pyrido[2,3-d] pyrimidine dihydrochloride (ABT-702) (1 mg). DPCPX is known to occupy cerebral A(1)R, whereas ethanol and ABT-702 increase extracellular adenosine. In groups 1 and 3, the brain was clearly visualized. High uptake of (11)C-MPDX was noted in striatum, hippocampus, and cerebellum. In group 2, tracer uptake was strongly suppressed and regional differences were abolished. The treatment of group 3 resulted in an unexpected 40%-45% increase of the cerebral uptake of radioactivity as indicated by increases of PET standardized uptake value, distribution volume from Logan plot, nondisplaceable binding potential from 2-tissue-compartment model fit, and standardized uptake value from a biodistribution study performed after the PET scan. The partition coefficient of the tracer (K(1)/k(2) from the model fit) was not altered under the study conditions. (11)C-MPDX shows a regional distribution in rat brain consistent with binding to A(1)R. Tracer binding is blocked by the selective A

  5. ADENOSINE DEAMINASE ACTIVITY IN TYPE 2 DIABETES MELLITUS

    Directory of Open Access Journals (Sweden)

    Farija Peruvankuzhiyil

    2017-01-01

    Full Text Available BACKGROUND Altered blood levels of adenosine deaminase may help in predicting immunological dysfunction in diabetic individuals. But very few studies exist on ADA activity in type 2 diabetes mellitus. Aim of this study is to compare serum adenosine deaminase activity in type 2 diabetic patients with non-diabetic control. MATERIALS AND METHODS A comparative study design was used in data collection process. The study was conducted in 40 type 2 diabetes mellitus patients attending diabetic clinic or admitted in the medicine ward for metabolic control of diabetes in medical college, Calicut from January 2011 to January 2012. The adenosine deaminase (ADA level in the serum is measured by endpoint method in these patients. The results were expressed as mean and standard deviation. The statistical significance of the differences between the values was assessed by ANOVA. RESULTS Among 40 diabetic patients, mean ADA level in the serum is 38.56, SD±6.72 (min 30, max 53. Mean ADA level in the serum in the control group is 22.04±4.625 (min 13, max 29. CONCLUSION ADA level in the serum is found to be increased indicating its role as an important immunoenzyme marker in the aetiopathology of type 2 diabetes mellitus.

  6. Intracellular phosphorylation of benzyladenosine is related to apoptosis induction in tobacco BY-2 cells

    Czech Academy of Sciences Publication Activity Database

    Mlejnek, P.; Doležel, Jaroslav; Procházka, S.

    2003-01-01

    Roč. 26, č. 10 (2003), s. 1723-1735 ISSN 0140-7791 R&D Projects: GA MŠk LN00A081 Institutional research plan: CEZ:AV0Z5038910 Keywords : adenosine 5'-triphosphate * cytokinin * N6-benzyladenine 9-riboside Subject RIV: ED - Physiology Impact factor: 3.613, year: 2003

  7. Bioluminometric assay of ATP in mouse brain

    Indian Academy of Sciences (India)

    Firefly luciferase bioluminescence (FLB) is a highly sensitive and specific method for the analysis of adenosine-5-triphosphate (ATP) in biological samples. Earlier attempts to modify the FLB test for enhanced sensitivity have been typically based on in vitro cell systems. This study reports an optimized FLB procedure for the ...

  8. A futile cycle, formed between two ATP-dependant γ-glutamyl cycle ...

    Indian Academy of Sciences (India)

    Cystinosis, an inherited disease caused by a defect in the lysosomal cystine transporter (CTNS), is characterized by renal proximal tubular dysfunction. Adenosine triphosphate (ATP) depletion appears to be a key event in the pathophysiology of the disease, even though the manner in which ATP depletion occurs is still a ...

  9. Targeting Adenosine Signaling in Parkinson's Disease: From Pharmacological to Non-pharmacological Approaches

    Directory of Open Access Journals (Sweden)

    Luiza R. Nazario

    2017-11-01

    Full Text Available Parkinson's disease (PD is one of the most prevalent neurodegenerative disease displaying negative impacts on both the health and social ability of patients and considerable economical costs. The classical anti-parkinsonian drugs based in dopaminergic replacement are the standard treatment, but several motor side effects emerge during long-term use. This mini-review presents the rationale to several efforts from pre-clinical and clinical studies using adenosine receptor antagonists as a non-dopaminergic therapy. As several studies have indicated that the monotherapy with adenosine receptor antagonists reaches limited efficacy, the usage as a co-adjuvant appeared to be a promising strategy. The formulation of multi-targeted drugs, using adenosine receptor antagonists and other neurotransmitter systems than the dopaminergic one as targets, have been receiving attention since Parkinson's disease presents a complex biological impact. While pharmacological approaches to cure or ameliorate the conditions of PD are the leading strategy in this area, emerging positive aspects have arisen from non-pharmacological approaches and adenosine function inhibition appears to improve both strategies.

  10. Adenosine concentration in the porcine coronary artery wall and A2A receptor involvement in hypoxia-induced vasodilatation.

    Science.gov (United States)

    Frøbert, Ole; Haink, Gesine; Simonsen, Ulf; Gravholt, Claus H; Levin, Max; Deussen, Andreas

    2006-01-15

    We tested whether hypoxia-induced coronary artery dilatation could be mediated by an increase in adenosine concentration within the coronary artery wall or by an increase in adenosine sensitivity. Porcine left anterior descendent coronary arteries, precontracted with prostaglandin F(2alpha) (10(-5) M), were mounted in a pressure myograph and microdialysis catheters were inserted into the tunica media. Dialysate adenosine concentrations were analysed by HPLC. Glucose, lactate and pyruvate were measured by an automated spectrophotometric kinetic enzymatic analyser. The exchange fraction of [(14)C]adenosine over the microdialysis membrane increased from 0.32 +/- 0.02 to 0.46 +/- 0.02 (n = 4, P lactate/pyruvate ratio was significantly increased in hypoxic arteries but did not correlate with adenosine concentration. We conclude that hypoxia-induced coronary artery dilatation is not mediated by increased adenosine produced within the artery wall but might be facilitated by increased adenosine sensitivity at the A(2A) receptor level.

  11. Structural Mapping of Adenosine Receptor Mutations

    DEFF Research Database (Denmark)

    Jespers, Willem; Schiedel, Anke C; Heitman, Laura H

    2018-01-01

    The four adenosine receptors (ARs), A1, A2A, A2B, and A3, constitute a subfamily of G protein-coupled receptors (GPCRs) with exceptional foundations for structure-based ligand design. The vast amount of mutagenesis data, accumulated in the literature since the 1990s, has been recently supplemente...

  12. 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...... rest (0.13+/-0.03, 0.07+/-0.03, and 0.07+/-0.02 micromol/L, respectively) to exercise (10 W; 2.00+/-1.32, 2.08+/-1.23, and 1.65+/-0.50 micromol/L, respectively; Pskeletal muscle...... and demonstrates that adenosine and its precursors increase in the exercising muscle interstitium, at a rate associated with intensity of muscle contraction and the magnitude of muscle blood flow....

  13. Limitation of Infarct Size and No-Reflow by Intracoronary Adenosine Depends Critically on Dose and Duration.

    Science.gov (United States)

    Yetgin, Tuncay; Uitterdijk, André; Te Lintel Hekkert, Maaike; Merkus, Daphne; Krabbendam-Peters, Ilona; van Beusekom, Heleen M M; Falotico, Robert; Serruys, Patrick W; Manintveld, Olivier C; van Geuns, Robert-Jan M; Zijlstra, Felix; Duncker, Dirk J

    2015-12-28

    In the absence of effective clinical pharmacotherapy for prevention of reperfusion-mediated injury, this study re-evaluated the effects of intracoronary adenosine on infarct size and no-reflow in a porcine model of acute myocardial infarction using clinical bolus and experimental high-dose infusion regimens. Despite the clear cardioprotective effects of adenosine, when administered prior to ischemia, studies on cardioprotection by adenosine when administered at reperfusion have yielded contradictory results in both pre-clinical and clinical settings. Swine (54 ± 1 kg) were subjected to a 45-min mid-left anterior descending artery occlusion followed by 2 h of reperfusion. In protocol A, an intracoronary bolus of 3 mg adenosine injected over 1 min (n = 5) or saline (n = 10) was administered at reperfusion. In protocol B, an intracoronary infusion of 50 μg/kg/min adenosine (n = 15) or saline (n = 21) was administered starting 5 min prior to reperfusion and continued throughout the 2-h reperfusion period. In protocol A, area-at-risk, infarct size, and no-reflow were similar between groups. In protocol B, risk zones were similar, but administration of adenosine resulted in significant reductions in infarct size from 59 ± 3% of the area-at-risk in control swine to 46 ± 4% (p = 0.02), and no-reflow from 49 ± 6% of the infarct area to 26 ± 6% (p = 0.03). During reperfusion, intracoronary adenosine can limit infarct size and no-reflow in a porcine model of acute myocardial infarction. However, protection was only observed when adenosine was administered via prolonged high-dose infusion, and not via short-acting bolus injection. These findings warrant reconsideration of adenosine as an adjuvant therapy during early reperfusion. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  14. Inhibition of synaptically evoked cortical acetylcholine release by adenosine: an in vivo microdialysis study in the rat.

    Science.gov (United States)

    Materi, L M; Rasmusson, D D; Semba, K

    2000-01-01

    The release of cortical acetylcholine from the intracortical axonal terminals of cholinergic basal forebrain neurons is closely associated with electroencephalographic activity. One factor which may act to reduce cortical acetylcholine release and promote sleep is adenosine. Using in vivo microdialysis, we examined the effect of adenosine and selective adenosine receptor agonists and antagonists on cortical acetylcholine release evoked by electrical stimulation of the pedunculopontine tegmental nucleus in urethane anesthetized rats. All drugs were administered locally within the cortex by reverse dialysis. None of the drugs tested altered basal release of acetylcholine in the cortex. Adenosine significantly reduced evoked cortical acetylcholine efflux in a concentration-dependent manner. This was mimicked by the adenosine A(1) receptor selective agonist N(6)-cyclopentyladenosine and blocked by the selective A(1) receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX). The A(2A) receptor agonist 2-[p-(2-carboxyethyl)-phenethylamino]-5'-N-ethylcarboxamidoadenosi ne hydrochloride (CGS 21680) did not alter evoked cortical acetylcholine release even in the presence of DPCPX. Administered alone, neither DPCPX nor the non-selective adenosine receptor antagonist caffeine affected evoked cortical acetylcholine efflux. Simultaneous delivery of the adenosine uptake inhibitors dipyridamole and S-(4-nitrobenzyl)-6-thioinosine significantly reduced evoked cortical acetylcholine release, and this effect was blocked by the simultaneous administration of caffeine. These data indicate that activation of the A(1) adenosine receptor inhibits acetylcholine release in the cortex in vivo while the A(2A) receptor does not influence acetylcholine efflux. Such inhibition of cortical acetylcholine release by adenosine may contribute to an increased propensity to sleep during prolonged wakefulness.

  15. 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.

  16. Ecto-ATPase inhibition: ATP and adenosine release under physiological and ischemic in vivo conditions in the rat striatum.

    Science.gov (United States)

    Melani, Alessia; Corti, Francesca; Stephan, Holger; Müller, Christa E; Donati, Chiara; Bruni, Paola; Vannucchi, Maria Giuliana; Pedata, Felicita

    2012-01-01

    In the central nervous system (CNS) ATP and adenosine act as transmitters and neuromodulators on their own receptors but it is still unknown which part of extracellular adenosine derives per se from cells and which part is formed from the hydrolysis of released ATP. In this study extracellular concentrations of adenosine and ATP from the rat striatum were estimated by the microdialysis technique under in vivo physiological conditions and after focal ischemia induced by medial cerebral artery occlusion. Under physiological conditions, adenosine and ATP concentrations were in the range of 130 nmol/L and 40 nmol/L, respectively. In the presence of the novel ecto-ATPase inhibitor, PV4 (100 nmol/L), the extracellular concentration of ATP increased 12-fold to ~360 nmol/L but the adenosine concentration was not altered. This demonstrates that, under physiological conditions, adenosine is not a product of extracellular ATP. In the first 4h after ischemia, adenosine increased to ~690 nmol/L and ATP to ~50 nmol/L. In the presence of PV4 the extracellular concentration of ATP was in the range of 450 nmol/L and a significant decrease in extracellular adenosine (to ~270 nmol/L) was measured. The contribution of extracellular ATP to extracellular adenosine was maximal in the first 20 min after ischemia onset. Furthermore we demonstrated, by immunoelectron microscopy, the presence of the concentrative nucleoside transporter CNT2 on plasma and vesicle membranes isolated from the rat striatum. These results are in favor that adenosine is transported in vesicles and is released in an excitation-secretion manner under in vivo physiological conditions. Early after ischemia, extracellular ATP is hydrolyzed by ecto-nucleotidases which significantly contribute to the increase in extracellular adenosine. To establish the contribution of extracellular ATP to adenosine might constitute the basis for devising a correct putative purinergic strategy aimed at protection from ischemic damage

  17. A comparison of N-methyl-D-aspartate-evoked release of adenosine and [3H]norepinephrine from rat cortical slices

    International Nuclear Information System (INIS)

    Hoehn, K.; Craig, C.G.; White, T.D.

    1990-01-01

    Tetrodotoxin reduced N-methyl-D-aspartate (NMDA)-evoked release of adenosine by 35% but virtually abolished [3H]norepinephrine release. Although [3H]norepinephrine release from rat cortical slices evoked by 500 microM NMDA was abolished by 1.2 mM Mg++, which produces a voltage-sensitive, uncompetitive block of NMDA-channels, adenosine release was increased in the presence of Mg++. Partial depolarization with 12 mM K+ relieved the Mg++ block of 500 microM NMDA-evoked [3H]norepinephrine release but did not affect adenosine release, indicating that a Mg++ requirement for the adenosine release process per se cannot account for this discrepancy. NMDA was 33 times more potent in releasing adenosine than [3H]norepinephrine. At submaximal concentrations of NMDA (10 and 20 microM), adenosine release was augmented in Mg+(+)-free medium. Although a high concentration of the uncompetitive NMDA antagonist MK-801 [(+)-5-methyl-10,11,dihydro-5H-dibenzo[a,d]cyclohepten-5-10-imine maleate] (3 microM) blocked NMDA-evoked release of [3H]norepinephrine and adenosine, a lower concentration (300 nM) decreased NMDA-evoked [3H]norepinephrine release by 66% without affecting adenosine release. These findings suggest that maximal adenosine release occurs when relatively few NMDA receptors are activated, raising the possibility that spare receptors exist for NMDA-evoked adenosine release. Rather than acting as a protectant against excessive NMDA excitation, released adenosine might provide an inhibitory threshold which must be overcome for NMDA-mediated neurotransmission to proceed

  18. 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

  19. Adenosine 5'-Monophosphate Aerosol Challenge Does Not Provoke Airflow Limitation in Healthy Cats

    Directory of Open Access Journals (Sweden)

    K. Vondráková

    2006-01-01

    Full Text Available The purpose of our study was to investigate the effects of nebulized adenosine 5'- monophosphate on airflow limitation in healthy cats determined by barometric whole body plethysmography (BWBP, in comparison to the effects of carbachol. Ten healthy 4- to 6-year-old domestic shorthair cats were included in the study. Each cat was placed in a BWBP plexiglass chamber (volume 38 l. Changes in box pressure were measured at baseline and after nebulization of vehicle and increasing concentrations of carbachol and adenosine 5'- monophosphate. Airway responsiveness was monitored as increases in enhanced pause (PENH, a unitless variable derived from dose-response curves estimating airflow limitation. The chosen endpoint was the agonist concentration which increased PENH to 300% of the value obtained after saline nebulization (PCPENH 300. Inter-day repeatability of measurements was assessed by repeated bronchoprovocations with both agonists 2-3 days apart. For carbachol, PCPENH300 was reached in all cats and correlated significantly between days (mean ± SD; 0.54 ± 0.42 mg/ml and 0.64 ± 0.45 mg/ml respectively; r = 0.58, p < 0.05 In contrast, we found no reaction to adenosine 5'- monophosphate even with the highest concentration nebulized during both measurements. At baseline, mean ± SD PENH was 0.47 ± 0.18 and 0.58 ± 0.24 (measurements 1 and 2, whereas PENH after 500 mg/ml adenosine 5'- monophosphate was 0.46 ± 0.20 and 0.71 ± 0.37. All bronchoprovocation tests were well tolerated by the cats. We conclude that healthy airways in cats do not demonstrate airway responsiveness to inhaled adenosine 5'- monophosphate. This is in agreement with observations in humans as well as our previous findings in dogs, where adenosine 5'- monophosphate had no effect on healthy canine airways, but caused significant airflow limitation after induction of acute bronchitis. To define the value of bronchoprovocation testing with adenosine 5'- monophosphate in the feline

  20. High-performance sodium-organic battery by realizing four-sodium storage in disodium rhodizonate

    Science.gov (United States)

    Lee, Minah; Hong, Jihyun; Lopez, Jeffrey; Sun, Yongming; Feng, Dawei; Lim, Kipil; Chueh, William C.; Toney, Michael F.; Cui, Yi; Bao, Zhenan

    2017-11-01

    Sodium-ion batteries (SIBs) for grid-scale applications need active materials that combine a high energy density with sustainability. Given the high theoretical specific capacity 501 mAh g-1, and Earth abundance of disodium rhodizonate (Na2C6O6), it is one of the most promising cathodes for SIBs. However, substantially lower reversible capacities have been obtained compared with the theoretical value and the understanding of this discrepancy has been limited. Here, we reveal that irreversible phase transformation of Na2C6O6 during cycling is the origin of the deteriorating redox activity of Na2C6O6. The active-particle size and electrolyte conditions were identified as key factors to decrease the activation barrier of the phase transformation during desodiation. On the basis of this understanding, we achieved four-sodium storage in a Na2C6O6 electrode with a reversible capacity of 484 mAh g-1, an energy density of 726 Wh kg-1cathode, an energy efficiency above 87% and a good cycle retention.

  1. Lack of adenosine A(3) receptors causes defects in mouse peripheral blood parameters

    Czech Academy of Sciences Publication Activity Database

    Hofer, Michal; Pospíšil, Milan; Dušek, L.; Hoferová, Zuzana; Komůrková, Denisa

    2014-01-01

    Roč. 10, č. 3 (2014), s. 509-514 ISSN 1573-9538 R&D Projects: GA ČR(CZ) GAP303/11/0128 Institutional support: RVO:68081707 Keywords : Adenosine A(3) receptor * Adenosine A(3) receptor knockout mice * Hematopoiesis Subject RIV: BO - Biophysics Impact factor: 3.886, year: 2014

  2. Acute rejection after kidney transplantation promotes graft fibrosis with elevated adenosine level in rat.

    Directory of Open Access Journals (Sweden)

    Mingliang Li

    Full Text Available Chronic allograft nephropathy is a worldwide issue with the major feature of progressive allograft fibrosis, eventually ending with graft loss. Adenosine has been demonstrated to play an important role in process of fibrosis. Our study aimed to investigate the relationship between adenosine and fibrosis in renal allograft acute rejection in rat.Wistar rats and SD rats were selected as experimental animals. Our study designed two groups. In the allograft transplantation group, kidneys of Wistar rats were orthotopically transplanted into SD rat recipients, the same species but not genetically identical, to induce acute rejection. Kidney transplantations of SD rats to SD rats which were genetically identical were served as the control. We established rat models and detected a series of indicators. All data were analyzed statistically. P<0.05 was considered statistically significant.Compared with the control group, levels of adenosine increased significantly in the allograft transplantation group, in which acute rejection was induced (P<0.05. Progressive allograft fibrosis as well as collagen deposition were observed.These findings suggested that level of adenosine was upregulated in acute rejection after kidney allograft transplantation in rat. Acute rejection may promote renal allograft fibrosis via the adenosine signaling pathways.

  3. An adenylyl cyclase gene (NlAC9) influences growth and fecundity in the brown planthopper, Nilaparvata lugens (Stål) (Hemiptera: Delphacidae)

    Science.gov (United States)

    The cAMP/PKA intracellular signaling pathway is launched by adenylyl cyclase (AC) conversion of adenosine triphosphate (ATP) to 3', 5'-cyclic AMP (cAMP) and cAMP-dependent activation of PKA. Although this pathway is very well known in insect physiology, there is little to no information on it in som...

  4. Association of P2Y(2) receptor SNPs with bone mineral density and osteoporosis risk in a cohort of Dutch fracture patients

    DEFF Research Database (Denmark)

    Wesselius, Anke; Bours, Martijn J L; Henriksen, Zanne

    2013-01-01

    The P2Y(2) receptor is a G-protein-coupled receptor with adenosine 5'-triphosphate (and UTP) as natural ligands. It is thought to be involved in bone physiology in an anti-osteogenic manner. As several non-synonymous single nucleotide polymorphisms (SNPs) have been identified within the P2Y(2) re...

  5. An Anthropologist Looks at Malaria | Tobias | South African Medical ...

    African Journals Online (AJOL)

    Also, malaria may be associated with the lower levels of ATP (adenosine triphosphate) in the red blood cells of Blacks. Man's cultural evolution and especially the adoption of agriculture - may have played a big part in the establishment of areas of malarial hyperendemicity. Thus, indirectly, malaria may have helped the early ...

  6. Biotechnological storage and utilization of entrapped solar energy.

    Science.gov (United States)

    Bhattacharya, Sumana; Schiavone, Marc; Nayak, Amiya; Bhattacharya, Sanjoy K

    2005-03-01

    Our laboratory has recently developed a device employing immobilized F0F1 adenosine triphosphatase (ATPase) that allows synthesis of adenosine triphosphate (ATP) from adenosine 5'-diphosphate and inorganic phosphate using solar energy. We present estimates of total solar energy received by Earth's land area and demonstrate that its efficient capture may allow conversion of solar energy and storage into bonds of biochemicals using devices harboring either immobilized ATPase or NADH dehydrogenase. Capture and storage of solar energy into biochemicals may also enable fixation of CO2 emanating from polluting units. The cofactors ATP and NADH synthesized using solar energy could be used for regeneration of acceptor D-ribulose-1,5-bisphosphate from 3-phosphoglycerate formed during CO2 fixation.

  7. A cell wall-bound adenosine nucleosidase is involved in the salvage of extracellular ATP in Solanum tuberosum.

    Science.gov (United States)

    Riewe, David; Grosman, Lukasz; Fernie, Alisdair R; Zauber, Henrik; Wucke, Cornelia; Geigenberger, Peter

    2008-10-01

    Extracellular ATP (eATP) has recently been demonstrated to play a crucial role in plant development and growth. To investigate the fate of eATP within the apoplast, we used intact potato (Solanum tuberosum) tuber slices as an experimental system enabling access to the apoplast without interference of cytosolic contamination. (i) Incubation of intact tuber slices with ATP led to the formation of ADP, AMP, adenosine, adenine and ribose, indicating operation of apyrase, 5'-nucleotidase and nucleosidase. (ii) Measurement of apyrase, 5'-nucleotidase and nucleosidase activities in fractionated tuber tissue confirmed the apoplastic localization for apyrase and phosphatase in potato and led to the identification of a novel cell wall-bound adenosine nucleosidase activity. (iii) When intact tuber slices were incubated with saturating concentrations of adenosine, the conversion of adenosine into adenine was much higher than adenosine import into the cell, suggesting a potential bypass of adenosine import. Consistent with this, import of radiolabeled adenine into tuber slices was inhibited when ATP, ADP or AMP were added to the slices. (iv) In wild-type plants, apyrase and adenosine nucleosidase activities were found to be co-regulated, indicating functional linkage of these enzymes in a shared pathway. (v) Moreover, adenosine nucleosidase activity was reduced in transgenic lines with strongly reduced apoplastic apyrase activity. When taken together, these results suggest that a complete ATP salvage pathway is present in the apoplast of plant cells.

  8. Generation of adenosine tri-phosphate in Leishmania donovani amastigote forms.

    Science.gov (United States)

    Mondal, Subhasish; Roy, Jay Jyoti; Bera, Tanmoy

    2014-03-01

    Leishmania, the causative agent of various forms of leishmaniasis, is the significant cause of morbidity and mortality. Regarding energy metabolism, which is an essential factor for the survival, parasites adapt to the environment under low oxygen tension in the host using metabolic systems which are very different from that of the host mammals. We carried out the study of susceptibilities to different inhibitors of mitochondrial electron transport chain and studies on substrate level phosphorylation in wild-type L. donovani. The amastigote forms of L. donovani are independent on oxidative phosphorylation for ATP production. Indeed, its cell growth was not inhibited by excess oligomycin and dicyclohexylcarbodiimide, which are the most specific inhibitors of the mitochondrial Fo/F1-ATP synthase. In contrast, mitochondrial complex I inhibitor rotenone and complex III inhibitor antimycin A inhibited amastigote cell growth, suggesting the role of complex I and complex III in cell survival. Complex II appeared to have no role in cell survival. To further investigate the site of ATP production, we studied the substrate level phosphorylation, which was involved in the synthesis of ATP. Succinate-pyruvate couple showed the highest substrate level phosphorylation in amastigotes whereas NADH-fumarate and NADH-pyruvate couples failed to produce ATP. In contrast, NADPH-fumarate showed the highest rate of ATP formation in promastigotes. Therefore, we can conclude that substrate level phosphorylation is essential for the survival of amastigote forms of Leishmania donovani.

  9. Paul D. Boyer, Adenosine Triphosphate (ATP), and the Binding Change

    Science.gov (United States)

    Mechanism RSS Archive Videos XML DOE R&D Accomplishments DOE R&D Accomplishments searchQuery × Find searchQuery x Find DOE R&D Acccomplishments Navigation dropdown arrow The Basics Stories Snapshots R&D Nuggets Database dropdown arrow Search Tag Cloud Browse Reports Database Help

  10. Adenosine Deaminase Inhibitor EHNA Exhibits a Potent Anticancer Effect Against Malignant Pleural Mesothelioma

    Directory of Open Access Journals (Sweden)

    Yasuhiro Nakajima

    2015-01-01

    Full Text Available Background/Aims: Malignant pleural mesothelioma (MPM is an aggressive malignant tumor and an effective therapy has been little provided as yet. The present study investigated the possibility for the adenosine deaminase (ADA inhibitor EHNA as a target of MPM treatment. Methods: MTT assay, TUNEL staining, monitoring of intracellular adenosine concentrations, and Western blotting were carried out in cultured human MPM cell lines without and with knocking-down ADA. The in vivo effect of EHNA was assessed in mice inoculated with NCI-H2052 MPM cells. Results: EHNA induced apoptosis of human MPM cell lines in a concentration (0.01-1 mM- and treatment time (24-48 h-dependent manner, but such effect was not obtained with another ADA inhibitor pentostatin. EHNA increased intracellular adenosine concentrations in a treatment time (3-9 h-dependent manner. EHNA-induced apoptosis of MPM cells was mimicked by knocking-down ADA, and the effect was neutralized by the adenosine kinase inhibitor ABT-702. EHNA clearly suppressed tumor growth in mice inoculated with NCI-H2052 MPM cells. Conclusion: The results of the present study show that EHNA induces apoptosis of MPM cells by increasing intracellular adenosine concentrations, to convert to AMP, and effectively prevents MPM cell proliferation. This suggests that EHNA may be useful for treatment of the tragic neoplasm MPM.

  11. Progress towards novel adenosine receptor therapeutics gleaned from the recent patent literature.

    Science.gov (United States)

    Press, Neil J; Fozard, John R

    2010-08-01

    The principle of treating disease with selective adenosine receptor ligands has been demonstrated with drugs on the market, while the lesser understood receptor subtypes are still being probed with new and drug-like pharmaceutical tools. The field of adenosine receptor research is, therefore, highly important as an emerging and proven point of intervention in disease. From 2008 to 2009, > 120 primary patent applications have claimed adenosine receptor ligands, which we analyze by applicant and target. Particularly significant disclosures are described in detail, paying particular attention to the biological data marshalled to support the case. The first published disclosure of new compounds, compound uses or drug targets is often in the patent literature, which can be difficult to trawl, interpret and verify as it is not subject to peer review. We have critically reviewed this area and share our conclusions regarding progress, trends and identification of early tool compounds or compounds of potential clinical significance ahead of peer-reviewed publication. Adenosine receptor research is a thriving field with continuing claims of exciting new compounds with high specificity and intriguing examples of new uses for such ligands.

  12. Determination of Zidovudine Triphosphate Intracellular Concentrations in Peripheral Blood Mononuclear Cells from Human Immunodeficiency Virus-Infected Individuals by Tandem Mass Spectrometry

    Science.gov (United States)

    Font, Eva; Rosario, Osvaldo; Santana, Jorge; García, Hermes; Sommadossi, Jean-Pierre; Rodriguez, Jose F.

    1999-01-01

    Nucleoside reverse transcriptase inhibitors (NRTIs) used against the human immunodeficiency virus (HIV) need to be activated intracellularly to their triphosphate moiety to inhibit HIV replication. Intracellular concentrations of these NRTI triphosphates, especially zidovudine triphosphate (ZDV-TP), are relatively low (low numbers of femtomoles per 106 cells) in HIV-infected patient peripheral blood mononuclear cells. Recently, several methods have used either high-performance liquid chromatography (HPLC) or solid-phase extraction (SPE) coupled with radioimmunoassay to obtain in vivo measurements of ZDV-TP. The limit of detection (LOD) by these methods ranged from 20 to 200 fmol/106 cells. In this report, we describe the development of a method to determine intracellular ZDV-TP concentrations in HIV-infected patients using SPE and HPLC with tandem mass spectrometry for analysis. The LOD by this method is 4.0 fmol/106 cells with a linear concentration range of at least 4 orders of magnitude from 4.0 to 10,000 fmol/106 cells. In hispanic HIV-infected patients, ZDV-TP was detectable even when the sampling time after drug administration was 15 h. Intracellular ZDV-TP concentrations in these patients ranged from 41 to 193 fmol/106 cells. The low LOD obtained with this method will provide the opportunity for further in vivo pharmacokinetic studies of intracellular ZDV-TP in different HIV-infected populations. Furthermore, this methodology could be used to perform simultaneous detection of two or more NRTIs, such as ZDV-TP and lamivudine triphosphate. PMID:10582890

  13. Tolerance and diagnostic accuracy of an abbreviated adenosine infusion for myocardial scintigraphy: a randomized, prospective study.

    Science.gov (United States)

    Treuth, M G; Reyes, G A; He, Z X; Cwajg, E; Mahmarian, J J; Verani, M S

    2001-01-01

    The objectives of this study were 2-fold: (1) to determine the tolerance of adenosine perfusion tomography with the use of an abbreviated (3-minute) infusion in comparison to the standard (6-minute) infusion, and (2) to assess the relative diagnostic accuracy of a 3-minute adenosine infusion in patients referred for arteriography. An abbreviated adenosine infusion may decrease the frequency and duration of side effects and be a more cost-effective alternative. We prospectively randomized 599 patients undergoing adenosine myocardial perfusion tomography to either a 3-minute or 6-minute adenosine infusion at 140 microg/kg per minute. Among the 599 enrolled patients, 142 subsequently underwent coronary angiography. Patients randomized to the 3-minute adenosine infusion tolerated the procedure better than those randomized to the standard infusion (P <.01). Flushing, headache, neck pain, and atrioventricular block were all significantly less frequent (P <.01) with the abbreviated infusion. Moreover, patients receiving the abbreviated infusion had less hypotension and tachycardia (P <.05). The sensitivity of the test for detection of coronary artery disease was 88% for both the 3- and 6-minute infusions. In patients with abnormal scan results, perfusion defect size was slightly larger in those receiving a 6-minute infusion versus those receiving a 3-minute infusion (P =.05). An abbreviated 3-minute adenosine infusion, in combination with perfusion tomography, has similar sensitivity for detection of coronary artery disease and is better tolerated than the standard 6-minute infusion.

  14. Prospective Study of Adenosine on Atrioventricular Nodal Conduction in Pediatric and Young Adult Patients After Heart Transplantation.

    Science.gov (United States)

    Flyer, Jonathan N; Zuckerman, Warren A; Richmond, Marc E; Anderson, Brett R; Mendelsberg, Tamar G; McAllister, Jennie M; Liberman, Leonardo; Addonizio, Linda J; Silver, Eric S

    2017-06-20

    Supraventricular tachycardia is common after heart transplantation. Adenosine, the standard therapy for treating supraventricular tachycardia in children and adults without transplantation, is relatively contraindicated after transplantation because of a presumed risk of prolonged atrioventricular block in denervated hearts. This study tested whether adenosine caused prolonged asystole after transplantation and if it was effective in blocking atrioventricular nodal conduction in these patients. This was a single-center prospective clinical study including healthy heart transplant recipients 6 months to 25 years of age presenting for routine cardiac catheterization during 2015 to 2016. After catheterization, a transvenous pacing catheter was placed and adenosine was given following a dose-escalation protocol until atrioventricular block was achieved. The incidence of clinically significant asystole (≥12 seconds after adenosine) was quantified. The effects of patient characteristics on adenosine dose required to produce atrioventricular block and duration of effect were also measured. Eighty patients completed adenosine testing. No patient (0%; 95% confidence interval, 0-3) required rescue ventricular pacing. Atrioventricular block was observed in 77 patients (96%; 95% confidence interval, 89-99). The median longest atrioventricular block was 1.9 seconds (interquartile range, 1.4-3.2 seconds), with a mean duration of adenosine effect of 4.3±2.0 seconds. No patient characteristic significantly predicted the adenosine dose to produce atrioventricular block or duration of effect. Results were similar across patient weight categories. Adenosine induces atrioventricular block in healthy pediatric and young adult heart transplant recipients with minimal risk when low initial doses are used (25 μg/kg; 1.5 mg if ≥60 kg) and therapy is gradually escalated. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02462941. © 2017 American Heart Association, Inc.

  15. 2′-O Methylation of Internal Adenosine by Flavivirus NS5 Methyltransferase

    Science.gov (United States)

    Dong, Hongping; Chang, David C.; Hua, Maggie Ho Chia; Lim, Siew Pheng; Chionh, Yok Hian; Hia, Fabian; Lee, Yie Hou; Kukkaro, Petra; Lok, Shee-Mei; Dedon, Peter C.; Shi, Pei-Yong

    2012-01-01

    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 (m7GpppAm) 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. [Monocarboxylate transporter 1 enhances the sensitivity of breast cancer cells to 3-bromopyruvate in vitro].

    Science.gov (United States)

    Li, Qi-Xiang; Zhang, Pei; Liu, Fang; Wang, Xian-Zhi; Li, Lu; Wang, Zhong-Kun; Jiang, Chen-Chen; Zheng, Hai-Lun; Liu, Hao

    2017-05-20

    To investigate the role of monocarboxylate transporter 1 (MCT1) in enhancing the sensitivity of breast cancer cells to 3-bromopyruvate (3-BrPA). The inhibitory effect of 3-BrPA on the proliferation of breast cancer cells was assessed with MTT assay, and brominated propidium bromide single staining flow cytometry was used for detecting the cell apoptosis. An ELISA kit was used to detect the intracellular levels of hexokinase II, lactate dehydrogenase, lactate, and adenosine triphosphate, and Western blotting was performed to detect the expression of MCT1. MDA-MB-231 cells were transiently transfected with MCT1 cDNA for over-expressing MCT1, and the effect of 3-BrPA on the cell proliferation and adenosine triphosphate level was deteced. 3-BrPA did not produce significant effects on the proliferation and apoptosis of MDA-MB-231 cells, and the cells treated with 200 µmol/L 3-BrPA for 24 h showed an inhibition rate and an apoptosis rate of only 8.72% and 7.8%, respectively. The same treatment, however, produced an inhibition rate and an apoptosis rate of 84.6% and 82.3% in MCF-7 cells, respectively. In MDA-MB-231 cells with MCT1 overexpression, 200 µmol/L 3-BrPA resulted in an inhibition rate of 72.44%, significantly higher than that in the control cells (P<0.05); treatment of the cells with 25, 50, 100, and 200 µmol/L 3-BrPA for 6 h resulted in intracellular adenosine triphosphate levels of 96.98%, 88.44%, 43.3% and 27.56% relative to the control level respectively. MCT1 can enhance the sensitivity of breast cancer cells to 3-BrPA possibly by transporting 3-BrPA into cells to inhibit cell glycolysis.

  17. Timescale of silver nanoparticle transformation in neural cell cultures impacts measured cell response

    International Nuclear Information System (INIS)

    Hume, Stephanie L.; Chiaramonti, Ann N.; Rice, Katherine P.; Schwindt, Rani K.; MacCuspie, Robert I.; Jeerage, Kavita M.

    2015-01-01

    Both serum protein concentration and ionic strength are important factors in nanoparticle transformation within cell culture environments. However, silver nanoparticles are not routinely tracked at their working concentration in the specific medium used for in vitro toxicology studies. Here we evaluated the transformation of electrostatically stabilized citrate nanoparticles (C-AgNPs) and sterically stabilized polyvinylpyrrolidone nanoparticles (PVP-AgNPs) in a low-serum (∼ 0.2 mg/mL bovine serum albumin) culture medium, while measuring the response of rat cortex neural progenitor cells, which differentiate in this culture environment. After 24 h, silver nanoparticles at concentrations up to 10 µg/mL did not affect adenosine triphosphate levels, whereas silver ions decreased adenosine triphosphate levels at concentrations of 1.1 µg/mL or higher. After 240 h, both silver nanoparticles, as well as silver ion, unambiguously decreased adenosine triphosphate levels at concentrations of 1 and 1.1 µg/mL, respectively, suggesting particle dissolution. Particle transformation was investigated in 1:10 diluted, 1:2 diluted, or undiluted differentiation medium, all having an identical protein concentration, to separate the effect of serum protein stabilization from ionic strength destabilization. Transmission electron microscopy images indicated that particles in 1:10 medium were not surrounded by proteins, whereas particles became clustered within a non-crystalline protein matrix after 24 h in 1:2 medium and at 0 h in undiluted medium. Despite evidence for a protein corona, particles were rapidly destabilized by high ionic strength media. Polyvinylpyrrolidone increased the stability of singly dispersed particles compared to citrate ligands; however, differences were negligible after 4 h in 1:2 medium or after 1 h in undiluted medium. Thus low-serum culture environments do not provide sufficient colloidal stability for long-term toxicology studies with citrate

  18. Timescale of silver nanoparticle transformation in neural cell cultures impacts measured cell response

    Energy Technology Data Exchange (ETDEWEB)

    Hume, Stephanie L.; Chiaramonti, Ann N.; Rice, Katherine P.; Schwindt, Rani K. [National Institute of Standards and Technology (NIST), Applied Chemicals and Materials Division (United States); MacCuspie, Robert I. [National Institute of Standards and Technology (NIST), Materials Measurement Science Division (United States); Jeerage, Kavita M., E-mail: jeerage@boulder.nist.gov [National Institute of Standards and Technology (NIST), Applied Chemicals and Materials Division (United States)

    2015-07-15

    Both serum protein concentration and ionic strength are important factors in nanoparticle transformation within cell culture environments. However, silver nanoparticles are not routinely tracked at their working concentration in the specific medium used for in vitro toxicology studies. Here we evaluated the transformation of electrostatically stabilized citrate nanoparticles (C-AgNPs) and sterically stabilized polyvinylpyrrolidone nanoparticles (PVP-AgNPs) in a low-serum (∼ 0.2 mg/mL bovine serum albumin) culture medium, while measuring the response of rat cortex neural progenitor cells, which differentiate in this culture environment. After 24 h, silver nanoparticles at concentrations up to 10 µg/mL did not affect adenosine triphosphate levels, whereas silver ions decreased adenosine triphosphate levels at concentrations of 1.1 µg/mL or higher. After 240 h, both silver nanoparticles, as well as silver ion, unambiguously decreased adenosine triphosphate levels at concentrations of 1 and 1.1 µg/mL, respectively, suggesting particle dissolution. Particle transformation was investigated in 1:10 diluted, 1:2 diluted, or undiluted differentiation medium, all having an identical protein concentration, to separate the effect of serum protein stabilization from ionic strength destabilization. Transmission electron microscopy images indicated that particles in 1:10 medium were not surrounded by proteins, whereas particles became clustered within a non-crystalline protein matrix after 24 h in 1:2 medium and at 0 h in undiluted medium. Despite evidence for a protein corona, particles were rapidly destabilized by high ionic strength media. Polyvinylpyrrolidone increased the stability of singly dispersed particles compared to citrate ligands; however, differences were negligible after 4 h in 1:2 medium or after 1 h in undiluted medium. Thus low-serum culture environments do not provide sufficient colloidal stability for long-term toxicology studies with citrate

  19. Comparison of adenosine and treadmill exercise thallium-201 stress tests for the detection of coronary artery disease

    International Nuclear Information System (INIS)

    Abe, Shinya; Takeishi, Yasuchika; Chiba, Junya; Ikeda, Kozue; Tomoike, Hitonobu

    1993-01-01

    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<0.001), systolic blood pressure (124 vs 164 mmHg, p<0.001), diastolic blood pressure (70 vs 86 mmHg, p<0.01) and rate 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. (author)

  20. Magnesium - distribution and basic metabolism | Olhaberry | South ...

    African Journals Online (AJOL)

    Magnesium is extensively distributed in soil, water and plants. It is essential for ehzymatic reactions requiring adenosine triphosphate, and the recommended dietary allowance in man is 5 - 10 mg/kg/d. About 50% of magnesium in man is stored in bone, where it is regulated by parathyroid hormone'and 1,25(OH)2-D3.

  1. Regulation of adenosine deaminase (ADA) on induced mouse experimental autoimmune uveitis (EAU) ‡

    Science.gov (United States)

    Liang, Dongchun; Zuo, Aijun; Zhao, Ronglan; Shao, Hui; Kaplan, Henry J.; Sun, Deming

    2016-01-01

    Adenosine is an important regulator of the immune response and adenosine deaminase (ADA) inhibits this regulatory effect by converting adenosine into functionally inactive molecules. Studies have shown that adenosine receptor (AR) agonists can be either anti- or pro-inflammatory. Clarification of the mechanisms that cause these opposing effects should provide a better guide for therapeutic intervention. In this study, we investigated the effect of ADA on the development of experimental autoimmune uveitis (EAU) induced by immunizing EAU-prone mice with a known uveitogenic peptide, IRBP1–20. Our results showed that the effective time to administer a single dose of ADA to suppress induction of EAU was 8–14 days post-immunization, shortly before EAU expression, but ADA treatment at other time points exacerbated disease. ADA preferentially inhibited Th17 responses and this effect was γδ T cell-dependent. Our results demonstrated that the existing immune status strongly influences the anti- or proinflammatory effects of ADA. Our observations should help improve the design of ADA- and AR-targeted therapies. PMID:26856700

  2. Energy status of pig donor organs after ischemia is independent of donor type.

    Science.gov (United States)

    Stadlbauer, Vanessa; Stiegler, Philipp; Taeubl, Philipp; Sereinigg, Michael; Puntschart, Andreas; Bradatsch, Andrea; Curcic, Pero; Seifert-Held, Thomas; Zmugg, Gerda; Stojakovic, Tatjana; Leopold, Barbara; Blattl, Daniela; Horki, Vera; Mayrhauser, Ursula; Wiederstein-Grasser, Iris; Leber, Bettina; Jürgens, Günther; Tscheliessnigg, Karlheinz; Hallström, Seth

    2013-04-01

    Literature is controversial whether organs from living donors have a better graft function than brain dead (BD) and non-heart-beating donor organs. Success of transplantation has been correlated with high-energy phosphate (HEP) contents of the graft. HEP contents in heart, liver, kidney, and pancreas from living, BD, and donation after cardiac death in a pig model (n=6 per donor type) were evaluated systematically. BD was induced under general anesthesia by inflating a balloon in the epidural space. Ten hours after confirmation, organs were retrieved. Cardiac arrest was induced by 9V direct current. After 10min of ventricular fibrillation without cardiac output, mechanical and medical reanimation was performed for 30min before organ retrieval. In living donors, organs were explanted immediately. Freeze-clamped biopsies were taken before perfusion with Celsior solution (heart) or University of Wisconsin solution (abdominal organs) in BD and living donors or with Histidine-Tryptophan-Ketoglutaric solution (all organs) in non-heart-beating donors, after perfusion, and after cold ischemia (4h for heart, 6h for liver and pancreas, and 12h for kidney). HEPs (adenosine triphosphate, adenosine diphosphate, adenosine monophosphate, and phosphocreatine), xanthine, and hypoxanthine were measured by high-performance liquid chromatography. Energy charge and adenosine triphosphate-to-adenosine diphosphate ratio were calculated. After ischemia, organs from different donor types showed no difference in energy status. In all organs, a decrease of HEP and an increase in hypoxanthine contents were observed during perfusion and ischemia, irrespective of the donor type. Organs from BD or non-heart-beating donors do not differ from living donor organs in their energy status after average tolerable ischemia. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Characteristics of high affinity and low affinity adenosine binding sites in human cerebral cortex

    International Nuclear Information System (INIS)

    John, D.; Fox, I.V.

    1986-01-01

    The binding characteristics of human brain cortical membrane fractions were evaluated to test the hypothesis that there are A 1 and A 2 adenosine binding sites. The ligands used were 2-chloro(8- 3 H) adenosine and N 6 -(adenine-2, 8- 3 H) cyclohexayladenosine. Binding of chloroadenosine to human brain cortical membranes was time dependent, reversible and concentration dependent. The kinetic constant determinations from binding studies of the adenosine receptor are presented. Utilizing tritium-cyclohexyladenosine as ligand the authors observed evidence for a high affinity binding site in human brain cortical membranes with a kd of 5 nM

  4. A new s-adenosylhomocysteine hydrolase-linked method for adenosine detection based on DNA-templated fluorescent Cu/Ag nanoclusters.

    Science.gov (United States)

    Ahn, Jun Ki; Kim, Hyo Yong; Baek, Songyi; Park, Hyun Gyu

    2017-07-15

    We herein describe a novel fluorescent method for the rapid and selective detection of adenosine by utilizing DNA-templated Cu/Ag nanoclusters (NCs) and employing s-adenosylhomocysteine hydrolase (SAHH). SAHH is allowed to promote hydrolysis reaction of s-adenosylhomocysteine (SAH) and consequently produces homocysteine, which would quench the fluorescence signal from DNA-templated Cu/Ag nanoclusters employed as a signaling probe in this study. On the other hand, adenosine significantly inhibits the hydrolysis reaction and prevent the formation of homocysteine. Consequently, highly enhanced fluorescence signal from DNA-Cu/Ag NCs is retained, which could be used to identify the presence of adenosine. By employing this design principle, adenosine was sensitively detected down to 19nM with high specificity over other adenosine analogs such as AMP, ADP, ATP, cAMP, guanosine, cytidine, and urine. Finally, the diagnostic capability of this method was successfully verified by reliably detecting adenosine present in a real human serum sample. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Activation of adenosine receptors and inhibition of cyclooxygenases: two recent pharmacological approaches to modulation of radiation suppressed hematopoiesis

    International Nuclear Information System (INIS)

    Hofer, M.; Pospisil, M.; Vacek, A.; Hola, J.; Weiterova, L.; Streitova, D.; Znojil, V.

    2008-01-01

    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

  6. 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......− 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 (Vte......) 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 Vte, an equivalent short-circuit current (Isc), and whole-cell Cl− currents were inhibited...

  7. Intraerythrocytic organic phosphates and hemoglobins of skua - Catharacta maccormicki (Stercoraridae: at two different stages of the year in relation to Antartic migration

    Directory of Open Access Journals (Sweden)

    Gustavo Fraga Landini

    2013-08-01

    Full Text Available Catharacta maccormicki blood samples were collected in the winter (October and in the summer (February in order to study the intraerythrocytic organic phosphates, hemoglobin (Hb electrophoretic patterns, oxygen blood equilibrium and stripped Hbs, as well as the effect of 2,3-biphosphoglycerate (BPG and inositol hexaphosphate (IHP on oxygen affinity. All the samples (five from the winter and five from the summer showed the same electrophoretic pattern: one minor fast component and one major slow one. No differences in oxygen affinity and Bohr effect in the samples collected in the winter and in the summer were found. Oxygen affinity was higher in the stripped Hb than in the blood. BPG seemed to have no effect on the functional properties of skua Hb while IHP does. No BPG was found in any sample. Both inositol pentaphosphate (IP5 and IHP were found in all the samples. The IP5/IHP ratio in the winter samples was 3.0 while in summer 3.5. Adenosine diphosphate (ADP was found in samples from both the seasons. Adenosine monophosphate (AMP and adenosine triphosphate (ATP were present only in the summer samples while guanosine triphosphate (GTP was found in the winter samples. Since IP5 and IHP are very powerful HB allosteric effectors, ATP and GTP might function as other protein modulators.

  8. Determination of pKa constants of hypericin in aqueous solution of the anti-allergic hydrotropic drug Cromolyn disodium salt

    Science.gov (United States)

    Keša, Peter; Antalík, Marián

    2017-05-01

    In this work we established three from altogether six proton dissociation constants (pKa) of hydroxyl groups of hypericin in its monomeric form. The monomeric state of hypericin (5.0 × 10-6 mol·L-1) in aqueous solution was stabilised by the presence of hydrotropic drug Cromolyn disodium salt (6.0 × 10-2 mol·L-1). Data show that one acid-base transition occurs with the pKa of 7.8 and the other two are characterised by the apparent single pKa of 11.5. The spectral changes of hypericin above pH 13 indicate that the last two hydroxyls are deporotonized at this high pH values.

  9. Extracellular adenosine production by ecto-5′-nucleotidase (CD73) enhances radiation-induced lung fibrosis

    Science.gov (United States)

    Wirsdörfer, Florian; de Leve, Simone; Cappuccini, Federica; Eldh, Therese; Meyer, Alina V.; Gau, Eva; Thompson, Linda F.; Chen, Ning-Yuan; Karmouty-Quintana, Harry; Fischer, Ute; Kasper, Michael; Klein, Diana; Ritchey, Jerry W.; Blackburn, Michael R.; Westendorf, Astrid M.; Stuschke, Martin; Jendrossek, Verena

    2016-01-01

    Radiation-induced pulmonary fibrosis is a severe side effect of thoracic irradiation, but its pathogenesis remains poorly understood and no effective treatment is available. In this study, we investigated the role of the extracellular adenosine as generated by the ecto-5'-nucleotidase CD73 in fibrosis development after thoracic irradiation. Exposure of wild-type C57BL/6 mice to a single dose (15 Gray) of whole thorax irradiation triggered a progressive increase in CD73 activity in the lung between 3 and 30 weeks post-irradiation. In parallel, adenosine levels in bronchoalveolar lavage fluid (BALF) were increased by approximately three-fold. Histological evidence of lung fibrosis was observed by 25 weeks after irradiation. Conversely, CD73-deficient mice failed to accumulate adenosine in BALF and exhibited significantly less radiation-induced lung fibrosis (P<0.010). Furthermore, treatment of wild-type mice with pegylated adenosine deaminase (PEG-ADA) or CD73 antibodies also significantly reduced radiation-induced lung fibrosis. Taken together, our findings demonstrate that CD73 potentiates radiation-induced lung fibrosis, suggesting that existing pharmacological strategies for modulating adenosine may be effective in limiting lung toxicities associated with the treatment of thoracic malignancies. PMID:26921334

  10. Adenosine deaminase production by an endophytic bacterium (Lysinibacillus sp.) from Avicennia marina.

    Science.gov (United States)

    Kathiresan, Kandasamy; Saravanakumar, Kandasamy; Sahu, Sunil Kumar; Sivasankaran, Muthu

    2014-06-01

    The present study was carried out with the following objectives: (1) to isolate the endophytic bacilli strains from the leaves of mangrove plant Avicennia marina, (2) to screen the potential strains for the production of adenosine deaminase, (3) to statistically optimize the factors that influence the enzyme activity in the potent strain, and (4) to identify the potent strain using 16S rRNA sequence and construct its phylogenetic tree. The bacterial strains isolated from the fresh leaves of a mangrove A. marina were assessed for adenosine deaminase activity by plating method. Optimization of reaction process was carried out using response surface methodology of central composite design. The potent strain was identified based on 16S rRNA sequencing and phylogeny. Of five endophytic strains, EMLK1 showed a significant deaminase activity over other four strains. The conditions for maximum activity of the isolated adenosine deaminase are described. The potent strain EMLK1 was identified as Lysinibacillus sp. (JQ710723) being the first report as a mangrove endophyte. Mangrove-derived endophytic bacillus strain Lysinibacillus sp. EMLK1 is proved to be a promising source for the production of adenosine deaminase and this enzyme deserves further studies for purification and its application in disease diagnosis.

  11. The adenosine-triphosphatase system responsible for cation transport in electric organ: exclusion of phospholipids as intermediates

    Science.gov (United States)

    Glynn, I. M.; Slayman, Carolyn W.; Eichberg, J.; Dawson, R. M. C.

    1965-01-01

    1. Subcellular fractions were prepared from the electric organs of Electrophorus and Torpedo and assayed for adenosine-triphosphatase activity. 2. Treatment of the `low-speed' fraction from Torpedo with m-urea gave an adenosine-triphosphatase preparation that was almost completely (98%) inhibited by ouabain (0·1mg./ml.) and dependent on the simultaneous presence of Na+ and K+. 3. The adenosine-triphosphatase preparations were exposed to [γ-32P]ATP for 30sec. in the presence of (i) Na+, (ii) K+, (iii) Na++K+ and (iv) Na++K++ouabain. No significant labelling of phosphatidic acid, triphosphoinositide or any other phospholipid was observed. 4. The results suggest that phospholipids do not act as phosphorylated intermediates in the `transport adenosine-triphosphatase' system of electric organ. PMID:14340060

  12. Shifting the paradigm

    DEFF Research Database (Denmark)

    Kiss, Katalin; Brozik, Anna; Kucsma, Nora

    2012-01-01

    ABCB6, a member of the adenosine triphosphate-binding cassette (ABC) transporter family, has been proposed to be responsible for the mitochondrial uptake of porphyrins. Here we show that ABCB6 is a glycoprotein present in the membrane of mature erythrocytes and in exosomes released from reticuloc...... paradigm linking the expression and function of ABCB6 to mitochondria....

  13. 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

    1. The present study examined the capacity for adenosine formation, uptake and metabolism in contracting primary rat muscle cells and in microvascular endothelial cells in culture. 2. Strong and moderate electrical simulation of skeletal muscle cells led to a significantly greater increase....... 3. Addition of microvascular endothelial cells to the cultured skeletal muscle cells enhanced the contraction-induced accumulation of extracellular adenosine (P Skeletal muscle cells were...... 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 contracted, but not in the moderately contracted muscle cells...

  14. Structural basis of the substrate specificity of Bacillus cereus adenosine phosphorylase

    Energy Technology Data Exchange (ETDEWEB)

    Dessanti, Paola; Zhang, Yang; Allegrini, Simone; Tozzi, Maria Grazia; Sgarrella, Francesco; Ealick, Steven E. (Cornell); (Sassari); (Pisa)

    2012-10-08

    Purine nucleoside phosphorylases catalyze the phosphorolytic cleavage of the glycosidic bond of purine (2{prime}-deoxy)nucleosides, generating the corresponding free base and (2{prime}-deoxy)ribose 1-phosphate. Two classes of PNPs have been identified: homotrimers specific for 6-oxopurines and homohexamers that accept both 6-oxopurines and 6-aminopurines. Bacillus cereus adenosine phosphorylase (AdoP) is a hexameric PNP; however, it is highly specific for 6-aminopurines. To investigate the structural basis for the unique substrate specificity of AdoP, the active-site mutant D204N was prepared and kinetically characterized and the structures of the wild-type protein and the D204N mutant complexed with adenosine and sulfate or with inosine and sulfate were determined at high resolution (1.2-1.4 {angstrom}). AdoP interacts directly with the preferred substrate through a hydrogen-bond donation from the catalytically important residue Asp204 to N7 of the purine base. Comparison with Escherichia coli PNP revealed a more optimal orientation of Asp204 towards N7 of adenosine and a more closed active site. When inosine is bound, two water molecules are interposed between Asp204 and the N7 and O6 atoms of the nucleoside, thus allowing the enzyme to find alternative but less efficient ways to stabilize the transition state. The mutation of Asp204 to asparagine led to a significant decrease in catalytic efficiency for adenosine without affecting the efficiency of inosine cleavage.

  15. Thallium-201 myocardial perfusion imaging during adenosine-induced coronary vasodilation in patients with ischemic heart disease

    International Nuclear Information System (INIS)

    Takeishi, Yasuchika; Chiba, Junya; Abe, Shinya

    1992-01-01

    Thallium-201 ( 201 Tl) 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 201 Tl was administered in a separate vein at the end of third minutes 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 spical levels and a vertical long axis image at the mid left ventricle were used. The regions with decreased 201 Tl 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 201 Tl myocardial imaging during adenosine infusion was considered to be safe and useful for evaluating the patients with ischemic heart disease. (author)

  16. 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.

  17. Isozyme-specific enzyme inhibitors. 14. 5'(R)-C-[(L-homocystein-S-yl)methyl]adenosine 5'-(beta,gamma-imidotriphosphate), a potent inhibitor of rat methionine adenosyltransferases.

    Science.gov (United States)

    Kappler, F; Vrudhula, V M; Hampton, A

    1987-09-01

    The title compound is a covalent adduct of L-methionine (Met) and beta,gamma-imido-ATP. In its synthesis the N-Boc derivative of 5'(R)-C-(aminomethyl)-N6-benzoyl-5'-O-tosyl-2',3'-O- isopropylidenadenosine was converted by the successive actions of CF3CO2H and HNO2 into the corresponding 5'(R)-C-hydroxymethyl derivative. Treatment of this with disodium L-homocysteinate led to attack of sulfur at C6', apparently via a 5',6'-epoxide, and to total stereoselective inversion at C5' to furnish, after debenzoylation, 5'(R)-C-(L-homocystein-S-ylmethyl)-2',3'-O-isopropylidene ade nosine. The 5' configuration was established by conversion of this into the known 5'(S)-C-methyl-2',3'-O-isopropylidene adenosine with Raney nickel. The alpha-amino acid residue was protected as an N-Boc methyl ester, after which the 5'-hydroxyl was phosphorylated with benzyl phosphate and dicyclohexylcarbodiimide. The phosphoanhydride bond with inorganic imidodiphosphate was then created by established methods. Finally, blocking groups were removed under conditions that gave the desired adduct with no racemization of its L-methionine residue. It was a potent inhibitor [KM(ATP)/Ki = 1080; KM(Met)/Ki = 7.7] of the M-2 (normal tissue) form of rat methionine adenosyltransferase and of the M-T (hepatoma tissue) form [KM(ATP)/Ki = 670; KM(Met)/Ki = 22]. Inhibitions were competitive with respect to ATP or to L-methionine, indicating a dual substrate site mode of binding to the enzyme forms.

  18. Intracellular ATP influences synaptic plasticity in area CA1 of rat hippocampus via metabolism to adenosine and activity-dependent activation of adenosine A1 receptors.

    Science.gov (United States)

    zur Nedden, Stephanie; Hawley, Simon; Pentland, Naomi; Hardie, D Grahame; Doney, Alexander S; Frenguelli, Bruno G

    2011-04-20

    The extent to which brain slices reflect the energetic status of the in vivo brain has been a subject of debate. We addressed this issue to investigate the recovery of energetic parameters and adenine nucleotides in rat hippocampal slices and the influence this has on synaptic transmission and plasticity. We show that, although adenine nucleotide levels recover appreciably within 10 min of incubation, it takes 3 h for a full recovery of the energy charge (to ≥ 0.93) and that incubation of brain slices at 34°C results in a significantly higher ATP/AMP ratio and a threefold lower activity of AMP-activated protein kinase compared with slices incubated at room temperature. Supplementation of artificial CSF with d-ribose and adenine (Rib/Ade) increased the total adenine nucleotide pool of brain slices, which, when corrected for the influence of the dead cut edges, closely approached in vivo values. Rib/Ade did not affect basal synaptic transmission or paired-pulse facilitation but did inhibit long-term potentiation (LTP) induced by tetanic or weak theta-burst stimulation. This decrease in LTP was reversed by strong theta-burst stimulation or antagonizing the inhibitory adenosine A(1) receptor suggesting that the elevated tissue ATP levels had resulted in greater activity-dependent adenosine release during LTP induction. This was confirmed by direct measurement of adenosine release with adenosine biosensors. These observations provide new insight into the recovery of adenine nucleotides after slice preparation, the sources of loss of such compounds in brain slices, the means by which to restore them, and the functional consequences of doing so.

  19. The Use of Adenosine Agonists to Treat Nerve Agent-Induced Seizure and Neuropathology

    Science.gov (United States)

    2016-09-01

    not be cited for purposes of advertisement . REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public reporting burden for this...survivability. That was an important step to clinical relevancy as it was feared that ADO’s depression of cardiovascular output would exacerbate...kainate, adenosine and neuropeptide Y receptors. Neurochemical Research. 28: 1501-1515. 23. Bjorness, T. E. & R. W. Greene . 2009. Adenosine and sleep

  20. Autoradiographic localization of adenosine receptors in rat brain using [3H]cyclohexyladenosine

    International Nuclear Information System (INIS)

    Goodman, R.R.; Synder, S.H.

    1982-01-01

    Adenosine (A1) receptor binding sites have been localized in rat brain by an in vitro light microscopic autoradiographic method. The binding of [ 3 H]N6-cyclohexyladenosine to slide-mounted rat brain tissue sections has the characteristics of A1 receptors. It is saturable with high affinity and has appropriate pharmacology and stereospecificity. The highest densities of adenosine receptors occur in the molecular layer of the cerebellum, the molecular and polymorphic layers of the hippocampus and dentate gyrus, the medial geniculate body, certain thalamic nuclei, and the lateral septum. High densities also are observed in certain layers of the cerebral cortex, the piriform cortex, the caudate-putamen, the nucleus accumbens, and the granule cell layer of the cerebellum. Most white matter areas, as well as certain gray matter areas, such as the hypothalamus, have negligible receptor concentrations. These localizations suggest possible central nervous system sites of action of adenosine

  1. Adenosine-deaminase (ADA activity in Psoriasis (A Preliminary Study

    Directory of Open Access Journals (Sweden)

    S D Chaudhry

    1988-01-01

    Full Text Available Study of adenosine-deaminase activity ′in 23 patients hav-mg psoriasis compared with an equal number of healthy controls revealed significantly high ADA-activity in the psotiatic patients.

  2. Mechanism of protection of adenosine from sulphate radical anion ...

    Indian Academy of Sciences (India)

    Unknown

    Keywords. Repair by caffeic acid; repair of adenosine radicals; oxidation by sulphate radical anions. ... known that hydroxycinnamic acids are natural anti- oxidants ... acid. 2. Experimental ..... ously and independently under kinetic conditions at.

  3. Comparative study of adenosine and exercise 201Tl myocardial perfusion tomographic imaging for detection of coronary heart disease

    International Nuclear Information System (INIS)

    Wang Xiong

    1997-01-01

    To compare diagnostic accuracy of adenosine and exercise 201 Tl myocardial perfusion tomographic imaging for detection of coronary heart disease (CHD) in patients with a normal rest ECG and no history of myocardial infarction, 81 patients with CHD and 10 normal control subjects underwent adenosine myocardial perfusion imaging, exercise nuclide myocardial perfusion imaging was performed in 117 patients with CHD and 16 normal control subjects, two groups also had coronary arteriography. Both exercise and adenosine testing parameters were analysed. It is shown: 1) The sensitivity and specificity for detection of CHD were 79% vs 80% for adenosine group and 81% vs 81% for exercise myocardial perfusion imaging group respectively. There was no significant difference in comparison with two matched groups (χ 2 = 1.13, χ 2 = 0.18, χ 2 = 0.12, P>0.05). 2) Side effects induced by adenosine accounted for 89% of patients, all symptoms were mild and disappeared quickly after the termination of the study except in 2 cases withdrawal of infusion needed because of severe angina pectoris. Adenosine myocardial perfusion imaging is a safe and sensitive method for detection of CHD. The diagnostic value of adenosine test is similar to that of exercise myocardial perfusion imaging and particularly useful in evaluating patients unable to perform exercise test or achieve adequate level of exercise

  4. Contributory role of adenosine deaminase in metabolic syndrome ...

    African Journals Online (AJOL)

    Adenosine deaminase (ADA) is an enzyme of purine metabolism commonly associated with severe combined immunodeficiency disease and believed to modulate bioactivity of insulin. Its contributory role in patients with metabolic syndrome (having features such as obesity, insulin resistance, fasting hyperglycaemia, lipid ...

  5. 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

    2015-08-05

    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. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. A3 Adenosine Receptors Modulate Hypoxia-inducible Factor-1a Expression in Human A375 Melanoma Cells

    Directory of Open Access Journals (Sweden)

    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.

  7. A2BR Adenosine Receptor Modulates Sweet Taste in Circumvallate Taste Buds

    Science.gov (United States)

    Yang, Dan; Shultz, Nicole; Vandenbeuch, Aurelie; Ravid, Katya; Kinnamon, Sue C.; Finger, Thomas E.

    2012-01-01

    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. PMID:22253866

  8. A2BR adenosine receptor modulates sweet taste in circumvallate taste buds.

    Science.gov (United States)

    Kataoka, Shinji; Baquero, Arian; Yang, Dan; Shultz, Nicole; Vandenbeuch, Aurelie; Ravid, Katya; Kinnamon, Sue C; Finger, Thomas E

    2012-01-01

    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.

  9. Abnormalities in the Polysomnographic, Adenosine and Metabolic Response to Sleep Deprivation in an Animal Model of Hyperammonemia

    Directory of Open Access Journals (Sweden)

    Selena Marini

    2017-08-01

    Full Text Available Patients with liver cirrhosis can develop hyperammonemia and hepatic encephalopathy (HE, accompanied by pronounced daytime sleepiness. Previous studies with healthy volunteers show that experimental increase in blood ammonium levels increases sleepiness and slows the waking electroencephalogram. As ammonium increases adenosine levels in vitro, and adenosine is a known regulator of sleep/wake homeostasis, we hypothesized that the sleepiness-inducing effect of ammonium is mediated by adenosine. Eight adult male Wistar rats were fed with an ammonium-enriched diet for 4 weeks; eight rats on standard diet served as controls. Each animal was implanted with electroencephalography/electromyography (EEG/EMG electrodes and a microdialysis probe. Sleep EEG recording and cerebral microdialysis were carried out at baseline and after 6 h of sleep deprivation. Adenosine and metabolite levels were measured by high-performance liquid chromatography (HPLC and targeted LC/MS metabolomics, respectively. Baseline adenosine and metabolite levels (12 of 16 amino acids, taurine, t4-hydroxy-proline, and acetylcarnitine were lower in hyperammonemic animals, while putrescine was higher. After sleep deprivation, hyperammonemic animals exhibited a larger increase in adenosine levels, and a number of metabolites showed a different time-course in the two groups. In both groups the recovery period was characterized by a significant decrease in wakefulness/increase in NREM and REM sleep. However, while control animals exhibited a gradual compensatory effect, hyperammonemic animals showed a significantly shorter recovery phase. In conclusion, the adenosine/metabolite/EEG response to sleep deprivation was modulated by hyperammonemia, suggesting that ammonia affects homeostatic sleep regulation and its metabolic correlates.

  10. 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 hum...

  11. Antitumor effect of cordycepin (3'-deoxyadenosine) on mouse melanoma and lung carcinoma cells involves adenosine A3 receptor stimulation.

    Science.gov (United States)

    Nakamura, Kazuki; Yoshikawa, Noriko; Yamaguchi, Yu; Kagota, Satomi; Shinozuka, Kazumasa; Kunitomo, Masaru

    2006-01-01

    An attempt was made to elucidate the molecular targetfor the antitumor effects of cordycepin (3'-deoxyadenosine) using non-selective and selective adenosine A1, A2a, A2b and A3 receptor agonists and antagonists. Although adenosine and 2'-deoxyadenosine (up to 100 microM) had no effect, cordycepin showed remarkable inhibitory effects on the growth curves of B16-BL6 mouse melanoma (IC50= 39 microM) and mouse Lewis lung carcinoma (IC50 = 48 microM) cell lines in vitro. Among the adenosine receptor agonists and antagonists used (up to 100 microM), only 2-chloro-N6-(3-iodobenzyl)-adenosine-5'-N-methyluronamide (Cl-IB-MECA), a selective adenosine A3 receptor agonist, notably inhibited the growth of both mouse tumor cell lines (B16-BL6; IC50 = 5 microM, LLC; 14 microM). In addition, the tumor growth inhibitory effect of cordycepin was antagonized by 3-ethyl 5-benzyl 2-methyl-6-phenyl-4-phenylethynyl-1,4-(+/-)-dihydropyridine-3,5-dicarboxylate (MRS1191), a selective adenosine A3 receptor antagonist. These results suggest that cordycepin exerts inhibitory effects on the growth of mouse melanoma and lung carcinoma cells by stimulating adenosine A3 receptors on tumor cells.

  12. Caffeine and Selective Adenosine Receptor Antagonists as New Therapeutic Tools for the Motivational Symptoms of Depression

    Directory of Open Access Journals (Sweden)

    Laura López-Cruz

    2018-06-01

    Full Text Available Major depressive disorder is one of the most common and debilitating psychiatric disorders. Some of the motivational symptoms of depression, such anergia (lack of self-reported energy and fatigue are relatively resistant to traditional treatments such as serotonin uptake inhibitors. Thus, new pharmacological targets are being investigated. Epidemiological data suggest that caffeine consumption can have an impact on aspects of depressive symptomatology. Caffeine is a non-selective adenosine antagonist for A1/A2A receptors, and has been demonstrated to modulate behavior in classical animal models of depression. Moreover, selective adenosine receptor antagonists are being assessed for their antidepressant effects in animal studies. This review focuses on how caffeine and selective adenosine antagonists can improve different aspects of depression in humans, as well as in animal models. The effects on motivational symptoms of depression such as anergia, fatigue, and psychomotor slowing receive particular attention. Thus, the ability of adenosine receptor antagonists to reverse the anergia induced by dopamine antagonism or depletion is of special interest. In conclusion, although further studies are needed, it appears that caffeine and selective adenosine receptor antagonists could be therapeutic agents for the treatment of motivational dysfunction in depression.

  13. Value of adenosine infusion for infarct size determination using real-time myocardial contrast echocardiography

    Directory of Open Access Journals (Sweden)

    da Luz Protásio

    2006-02-01

    Full Text Available Abstract Background Myocardial contrast echocardiography has been used for determination of infarct size (IS in experimental models. However, with intermittent harmonic imaging, IS seems to be underestimated immediately after reperfusion due to areas with preserved, yet dysfunctional, microvasculature. The use of exogenous vasodilators showed to be useful to unmask these infarcted areas with depressed coronary flow reserve. This study was undertaken to assess the value of adenosine for IS determination in an open-chest canine model of coronary occlusion and reperfusion, using real-time myocardial contrast echocardiography (RTMCE. Methods Nine dogs underwent 180 minutes of coronary occlusion followed by reperfusion. PESDA (Perfluorocarbon-Exposed Sonicated Dextrose Albumin was used as contrast agent. IS was determined by RTMCE before and during adenosine infusion at a rate of 140 mcg·Kg-1·min-1. Post-mortem necrotic area was determined by triphenyl-tetrazolium chloride (TTC staining. Results IS determined by RTMCE was 1.98 ± 1.30 cm2 and increased to 2.58 ± 1.53 cm2 during adenosine infusion (p = 0.004, with good correlation between measurements (r = 0.91; p 2 and showed no significant difference with IS determined by RTMCE before or during hyperemia. A slight better correlation between RTMCE and TTC measurements was observed during adenosine (r = 0.99; p Conclusion RTMCE can accurately determine IS in immediate period after acute myocardial infarction. Adenosine infusion results in a slight better detection of actual size of myocardial damage.

  14. Protective effect of ketotifen and disodium cromoglycate against bronchoconstriction induced by aspirin, benzoic acid or tartrazine in intolerant asthmatics.

    Science.gov (United States)

    Wüthrich, B

    1979-01-01

    Oral challenge tests with acetylsalicylic acid, tartrazine or benzoic acid were performed in 7 intolerant asthmatic patients after a 3-day treatment with either orally taken ketotifen (1 mg twice daily) or inhaled disodium cromoglycate (20 mg four times daily) at random. Protection was noted with ketotifen in 5, with DSCG in 3 patients. On the evaluation of the mean percentage of the maximum decline in the forced expiratory volume in 1 sec (FEV1) only ketotifen afforded significant protection statistically (p less than 0.05). All the intolerant asthmatics studies showed, as an immunological abnormity, a slight, but significant decrease of the C1-inhibitor levels. Moreover, in three out of these the alpha 1-antitrypsin serum values were under the lower normal range.

  15. D-ribose--an additive with caffeine.

    Science.gov (United States)

    Herrick, Jim; Shecterle, L M; St Cyr, J A

    2009-05-01

    Caffeine acts as a stimulant, in which approximately 90% of people in the United States consume daily. Besides its beneficial effects, many individuals have experienced unpleasant reactions following the consumption of caffeine: such as insomnia, an increase in heart rate, feelings of nervousness, headaches, occasional lightheadedness, a state of "jitters," and a potential "crash" state following its metabolism. Researchers have proposed mechanisms responsible for caffeine's interactions, which include its blocking capacity of adenosine receptors, its role with the pituitary gland, increasing levels of dopamine, and its role with the intracellular release of calcium from the sarcoplasmic reticulum, which is dependent on intracellular adenosine triphosphate levels. Specific substrates have been investigated to lessen the undesirable effects of caffeine and still preserve its stimulatory benefits. The results of these investigations have produced no positive consensus. However, D-ribose, an important pentose carbohydrate in the energy molecule of adenosine triphosphate, as well as our genetic code and other cellular processes, could offer such a solution to this problem. D-ribose could potentially aid in maintaining or potentially lowering extra-cellular adenosine concentrations, aid in the flux of intracellular calcium, aid in intracellular energy production, and potentially lessen the perceived "crash" state felt by many. Every cell requires adequate levels of energy to maintain its integrity and function. Caffeine has the potential to task this energy equilibrium. D-ribose with caffeine may be the substrate to aid in the potential intracellular energy demand, aid in lessening the perceived unpleasant side effects of caffeine, and still preserving the desired benefits of this stimulant consumed by all of us daily.

  16. Metabolic consequences of DNA damage: The role of poly (ADP-ribose) polymerase as mediator of the suicide response

    International Nuclear Information System (INIS)

    Berger, N.A.; Berger, S.J.

    1986-01-01

    Recent studies show that DNA damage can produce rapid alterations in steady state levels of deoxynucleoside triphosphate pools, for example, MNNG or uv-irradiation cause rapid increases in dATP and dTTP pools without significant changes in dGTP or dCTP pools. In vitro, studies with purified eukaryotic DNA polymerases show that the frequency of nucleotide misincorporation was affected by alterations in relative concentrations of the deoxynucleoside triphosphates. Thus the alterations in dNTP pool sizes that occur consequent to DNA damage may contribute to an increased mutagenic frequency. Poly(ADP-ribose) polymerase mediated suicide mechanism may participate in the toxicity of adenosine deaminase deficiency and severe combined immune deficiency disease in humans. Individuals with this disease suffer severe lymphopenia due to the toxic effects of deoxyadenosine. The lymphocytotoxic effect of adenosine deaminase deficiency can be simulated in lymphocyte cell lines from normal individuals by incubating them with the adenosine deaminase inhibitor, deoxycoformycin. Incubation of such leukocytes with deoxycoformycin and deoxyadenosine results in the gradual accumulation of DNA strand breaks and the depletion of NAD + leading to cell death over a period of several days. This depletion of NAD and loss of cell viability were effectively blocked by nicotinamide or 3-amino benzamide. Thus, persistent activation of poly(ADP-ribose) polymerase by unrepaired or recurrent DNA strand breaks may activate the suicide mechanism of cell death. This study provides a basis for the interesting suggestion that treatment with nicotinamide could block the persistent activity of poly(ADP-ribose) polymerase and may help preserve lymphocyte function in patients with adenosine deaminase deficiency. 16 refs., 3 figs., 2 tabs

  17. Prostatic acid phosphatase is an ectonucleotidase and suppresses pain by generating adenosine

    Science.gov (United States)

    Zylka, Mark J.; Sowa, Nathaniel A.; Taylor-Blake, Bonnie; Twomey, Margaret A.; Herrala, Annakaisa; Voikar, Vootele; Vihko, Pirkko

    2008-01-01

    SUMMARY Thiamine monophosphatase (TMPase, also known as Fluoride-Resistant Acid Phosphatase) is a classic histochemical marker of small-diameter dorsal root ganglia neurons. The molecular identity of TMPase is currently unknown. We found that TMPase is identical to the transmembrane isoform of Prostatic Acid Phosphatase (PAP), an enzyme with unknown molecular and physiological functions. We then found that PAP knockout mice have normal acute pain sensitivity but enhanced sensitivity in chronic inflammatory and neuropathic pain models. In gain-of-function studies, intraspinal injection of PAP protein has potent anti-nociceptive, anti-hyperalgesic and anti-allodynic effects that last longer than the opioid analgesic morphine. PAP suppresses pain by functioning as an ecto-5’-nucleotidase. Specifically, PAP dephosphorylates extracellular adenosine monophosphate (AMP) to adenosine and activates A1-adenosine receptors in dorsal spinal cord. Our studies reveal molecular and physiological functions for PAP in purine nucleotide metabolism and nociception and suggest a novel use for PAP in the treatment of chronic pain. PMID:18940592

  18. Roles of the adenosine receptor and CD73 in the regulatory effect of γδ T cells.

    Directory of Open Access Journals (Sweden)

    Dongchun Liang

    Full Text Available The adenosine A2A receptor (A2AR, the main functional adenosine receptor on murine T cells, plays a unique role in the attenuation of inflammation and tissue damage in vivo. Here, we showed that, of the immune cell types tested, activated γδ T cells expressed the highest levels of A2AR mRNA and that A2AR ligation inhibited αβ T cell activation, but enhanced γδ T cell activation. We also showed that the inhibitory effect of an adenosine receptor agonist on autoreactive T cells was prevented by addition of a low percentage of activated γδ T cells. Furthermore, compared to resting cells, activated γδ T cells expressed significantly lower levels of CD73, an enzyme involved in the generation of extracellular adenosine. Exogenous AMP had a significant inhibitory effect on autoreactive T cell responses, but only in the presence of CD73+ γδ T cells, and this effect was abolished by a CD73 inhibitor. Our results show that expression of increased amounts of A2AR allows γδ T cells to bind adenosine and thereby attenuate its suppressive effect, while decreased expression of CD73 results in less generation of adenosine in the inflammatory site. Together, these events allow activated γδ T cells to acquire increased proinflammatory activity, leading to augmented autoimmune responses.

  19. Comparison of effects of ATP-MgCl2 and adenosine-MgCl2 on renal function following ischemia

    International Nuclear Information System (INIS)

    Sumpio, B.E.; Hull, M.J.; Baue, A.E.; Chaudry, I.H.

    1987-01-01

    ATO-MgCl 2 administration had been shown to accelerate the recovery of renal function following warm ischemia. However, since the major breakdown product of ATP is adenosine, the relative contribution of ATP vs. adenosine in improving renal function following ischemia remains to be determined. To study this, kidneys were subjected to 45 min of normothermic ischemia and then perfused at 100 mmHg with oxygenated Krebs-HCO 3 buffer containing albumin, [ 3 H]inulin, substrates, and either 0.3 mM ATP-MgCl 2 or adenosine-MgCl 2 for 110 min. Perfusate and timed urine samples were collected and analyzed for radioactivity and [Na + ]. The functional parameters indicated that although adenosine-MgCl 2 treatment provided a transient improvement, it failed to provided a sustained improvement in renal function or attain control valued compared with ATP-MgCl 2 treatment. Thus, the salutary effects of ATP-MgCl 2 following warm ischemia in the kidney are not mediated by adenosine

  20. Comparison of fractional flow reserve measurements using intracoronary adenosine versus intracoronary sodium nitroprusside infusions in moderately stenotic coronary artery lesions

    Energy Technology Data Exchange (ETDEWEB)

    Safi, Morteza; Namazi, Mohammad Hasan; Fooladi, Esfandiar; Vakili, Hossein; Parsa, Saeed Alipour; Khaheshi, Isa [Cardiovascular Research Center, Modarres hospital, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Abbasi, Mohammad Amin [Department of Internal Medicine, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Movahed, Mohammad Reza, E-mail: rmova@aol.com [CareMore, Arizona, Tucson, AZ (United States); University of Arizona, Sarver Heart Center, Tucson, AZ (United States)

    2016-10-15

    Introduction: The aim of this study was to investigate the efficacy and safety of intracoronary (IC) sodium nitroprusside infusion in comparison to IC adenosine for fractional flow reserve (FFR) measurement in moderately diseased coronary artery lesions for functional assessment. Methods: During a nine month period, a consecutive of 98 patients with suspected or known coronary artery disease with moderate stenosis found during angiography (40% to 70% stenosis), were enrolled in this study. Hyperemia was induced by bolus doses of IC adenosine followed by sodium nitroprusside for FFR measurement. Results: Both IC adenosine and IC sodium nitroprusside induced similar and significant reduction in FFR. There was no statistically difference in FFR values between adenosine vs sodium nitroprusside infusions (mean FFR 84.3 ± 6.3 vs 85.7 ± 6.2, p = 0.1) respectively. Furthermore, comparing different FFR cut-off points between the groups (FFR < 0.75, 0.75–0.8 and > 0.8) showed no significant differences (p value = 0.7). Conclusion: An IC bolus of sodium nitroprusside (0.6 μg/kg) infusion induces a similar degree of hyperemia to IC bolus of 100–300 μg of adenosine. Therefore, IC sodium nitroprusside could be considered as an alternative drug to adenosine for FFR measurement with lower side effect profile. - Highlights: • Intracoronary (IC) sodium nitroprusside was compared with IC adenosine for FFR test. • IC adenosine and IC sodium nitroprusside induced similar reduction in FFR. • Different FFR cut-off points between the groups showed no significant differences. • IC sodium nitroprusside could be considered as an alternative to adenosine for FFR.

  1. 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.

  2. Plasma Adenosine Deaminase Enzyme Reduces with Treatment of ...

    African Journals Online (AJOL)

    olayemitoyin

    Plasma Adenosine Deaminase Enzyme Reduces with Treatment of Pulmonary Tuberculosis in Nigerian Patients: Indication for. Diagnosis and Treatment Monitoring. Ige O.a, Edem V.F.b and Arinola O.G.b,*. aDepartment of Medicine, University of Ibadan, Ibadan, Nigeria b Department of Chemical Pathology,. University of ...

  3. Contributory role of adenosine deaminase in metabolic syndrome

    African Journals Online (AJOL)

    olayemitoyin

    Cytokine balance was also changed in diet induced obese mice (Mito and Hiyosin, 2002). Although Mito et al (2000) ... immunity in man (Sadasivudu et al, 1982) adenosine deaminase modulates cell growth (Lelieuve et al, .... Colgiuri, S. (2002) The Carnivore Connection- evolution aspect of insulin resistance. Eur. J. Clin.

  4. Moonlighting adenosine deaminase: a target protein for drug development.

    Science.gov (United States)

    Cortés, Antoni; Gracia, Eduard; Moreno, Estefania; Mallol, Josefa; Lluís, Carme; Canela, Enric I; Casadó, Vicent

    2015-01-01

    Interest in adenosine deaminase (ADA) in the context of medicine has mainly focused on its enzymatic activity. This is justified by the importance of the reaction catalyzed by ADA not only for the intracellular purine metabolism, but also for the extracellular purine metabolism as well, because of its capacity as a regulator of the concentration of extracellular adenosine that is able to activate adenosine receptors (ARs). In recent years, other important roles have been described for ADA. One of these, with special relevance in immunology, is the capacity of ADA to act as a costimulator, promoting T-cell proliferation and differentiation mainly by interacting with the differentiation cluster CD26. Another role is the ability of ADA to act as an allosteric modulator of ARs. These receptors have very general physiological implications, particularly in the neurological system where they play an important role. Thus, ADA, being a single chain protein, performs more than one function, consistent with the definition of a moonlighting protein. Although ADA has never been associated with moonlighting proteins, here we consider ADA as an example of this family of multifunctional proteins. In this review, we discuss the different roles of ADA and their pathological implications. We propose a mechanism by which some of their moonlighting functions can be coordinated. We also suggest that drugs modulating ADA properties may act as modulators of the moonlighting functions of ADA, giving them additional potential medical interest. © 2014 Wiley Periodicals, Inc.

  5. Comparison of adenosine and exercise stress 201Tl myocardial perfusion imaging for diagnosing coronary heart disease in women

    International Nuclear Information System (INIS)

    Li Jiangjin; Ma Shuren; Meng Tao; Bao Zhi; Cui Jianhe

    2011-01-01

    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 χ 2 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); χ 2 =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)

  6. The immediate nucleotide precursor, guanosine triphosphate, in the riboflavin biosynthetic pathway

    International Nuclear Information System (INIS)

    Mitsuda, Hisateru; Nakajima, Kenji; Nadamoto, Tomonori

    1977-01-01

    In the present paper, the nucleotide precursor of riboflavin was investigated by experiments with labeled purines using non-growing cells of Eremothecium ashbyii. The added purines, at 10 -4 M, were effectively incorporated into riboflavin at an early stage of riboflavin biosynthesis under the experimental conditions. In particular, both labeled xanthine and labeled guanine were specifically transported to guanosine nucleotides, GMP, GDP, GDP-Mannose and GTP, in the course of the riboflavin biosynthesis. A comparison of specific activities of labeled guanosine nucleotides and labeled riboflavin indicated that the nucleotide precursor of riboflavin is guanosine triphosphate. From the results obtained, a biosynthetic pathway of riboflavin is proposed. (auth.)

  7. Carborane-linked 2'-deoxyuridine 5'-O-triphosphate as building block for polymerase synthesis of carborane-modified DNA.

    Science.gov (United States)

    Balintová, Jana; Simonova, Anna; Białek-Pietras, Magdalena; Olejniczak, Agnieszka; Lesnikowski, Zbigniew J; Hocek, Michal

    2017-11-01

    5-[(p-Carborane-2-yl)ethynyl]-2'-deoxyuridine 5'-O-triphosphate was synthesized and used as a good substrate in enzymatic construction of carborane-modified DNA or oligonucleotides containing up to 21 carborane moieties in primer extension reactions by DNA polymerases. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Safety of pyrroloquinoline quinone disodium salt as a novel food pursuant to Regulation (EC) No 258/97

    DEFF Research Database (Denmark)

    Sjödin, Anders Mikael

    2017-01-01

    Following a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver an opinion on pyrroloquinoline quinone disodium salt (PQQ), trade name BioPQQTM, as a novel food pursuant to Regulation (EC) No 258/97. PQQ is produced...... by fermentation using Hyphomicrobium denitrificans CK-275 and purification process. PQQ has a minimum purity of 99.0%. The information provided on the composition, specifications, batch-to-batch variability, stability and production process of PQQ is sufficient and does not raise safety concerns. The applicant...... intends to market PQQ for use in food supplements for healthy adults, except pregnant and lactating women, at a maximum proposed level of consumption of 20 mg/day (corresponding to 0.29 mg/kg bw per day for a 70-kg person). The proposed level of consumption is at least 250 times higher than the estimated...

  9. Basal and adenosine receptor-stimulated levels of cAMP are reduced in lymphocytes from alcoholic patients

    International Nuclear Information System (INIS)

    Diamond, I.; Wrubel, B.; Estrin, W.; Gordon, A.

    1987-01-01

    Alcoholism causes serious neurologic disease that may be due, in part, to the ability of ethanol to interact with neural cell membranes and change neuronal function. Adenosine receptors are membrane-bound proteins that appear to mediate some of the effects of ethanol in the brain. Human lymphocytes also have adenosine receptors, and their activation causes increases in cAMP levels. To test the hypothesis that basal and adenosine receptor-stimulated cAMP levels in lymphocytes might be abnormal in alcoholism, the authors studied lymphocytes from 10 alcoholic subjects, 10 age- and sex-matched normal individuals, and 10 patients with nonalcoholic liver disease. Basal and adenosine receptor-stimulated cAMP levels were reduced 75% in lymphocytes from alcoholic subjects. Also, there was a 76% reduction in ethanol stimulation of cAMP accumulation in lymphocytes from alcoholics. Similar results were demonstrable in isolated T cells. Unlike other laboratory tests examined, these measurements appeared to distinguish alcoholics from normal subjects and from patients with nonalcoholic liver disease. Reduced basal and adenosine receptor-stimulated levels of cAMP in lymphocytes from alcoholics may reflect a change in cell membranes due either to chronic alcohol abuse or to a genetic predisposition unique to alcoholic subjects

  10. No Effect of Nutritional Adenosine Receptor Antagonists on Exercise Performance in the Heat

    Science.gov (United States)

    2008-11-01

    358–363, 1996. 11. Cook NC, Samman S. Flavonoids —chemistry, metabolism, cardiopro- tective effects, and dietary sources. Nutr Biochem 7: 66–76, 1996...metabolism and health effects of dietary flavonoids in man. Biomed Pharmacother 51: 305–310, 1997. R400 ADENOSINE RECEPTOR ANTAGONISM AND EXERCISE IN THE HEAT...Interactions of flavonoids with adenosine receptors. J Med Chem 39: 781–788, 1996. 35. MacRae HS, Mefferd KM. Dietary antioxidant supplementation com

  11. Cerebral A1 adenosine receptors (A1AR) in liver cirrhosis

    International Nuclear Information System (INIS)

    Boy, Christian; Meyer, Philipp T.; Kircheis, Gerald; Haussinger, Dieter; Holschbach, Marcus H.; Coenen, Heinz H.; Herzog, Hans; Elmenhorst, David; Kaiser, Hans J.; Zilles, Karl; Bauer, Andreas

    2008-01-01

    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 1 adenosine receptors (A 1 AR), is likely to be involved. The present study investigates changes of cerebral A 1 AR binding in cirrhotic patients by means of positron emission tomography (PET) and [ 18 F]CPFPX, a novel selective A 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 max /K D ). Cortical and subcortical regions showed lower A 1 AR binding in cirrhotic patients than in controls. The aBP changes reached statistical significance vs healthy controls (p 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 1 AR density or affinity, as well as blockade of the A 1 AR by endogenous adenosine or exogenous xanthines. (orig.)

  12. Adenosine Receptors Differentially Regulate the Expression of Regulators of G-Protein Signalling (RGS 2, 3 and 4 in Astrocyte-Like Cells.

    Directory of Open Access Journals (Sweden)

    Till Nicolas Eusemann

    Full Text Available The "regulators of g-protein signalling" (RGS comprise a large family of proteins that limit by virtue of their GTPase accelerating protein domain the signal transduction of G-protein coupled receptors. RGS proteins have been implicated in various neuropsychiatric diseases such as schizophrenia, drug abuse, depression and anxiety and aggressive behaviour. Since conditions associated with a large increase of adenosine in the brain such as seizures or ischemia were reported to modify the expression of some RGS proteins we hypothesized that adenosine might regulate RGS expression in neural cells. We measured the expression of RGS-2,-3, and -4 in both transformed glia cells (human U373 MG astrocytoma cells and in primary rat astrocyte cultures stimulated with adenosine agonists. Expression of RGS-2 mRNA as well as RGS2 protein was increased up to 30-fold by adenosine agonists in astrocytes. The order of potency of agonists and the blockade by the adenosine A2B-antagonist MRS1706 indicated that this effect was largely mediated by adenosine A2B receptors. However, a smaller effect was observed due to activation of adenosine A2A receptors. In astrocytoma cells adenosine agonists elicited an increase in RGS-2 expression solely mediated by A2B receptors. Expression of RGS-3 was inhibited by adenosine agonists in both astrocytoma cells and astrocytes. However while this effect was mediated by A2B receptors in astrocytoma cells it was mediated by A2A receptors in astrocytes as assessed by the order of potency of agonists and selective blockade by the specific antagonists MRS1706 and ZM241385 respectively. RGS-4 expression was inhibited in astrocytoma cells but enhanced in astrocytes by adenosine agonists.

  13. The Role of Adenosine Receptors in Psychostimulant Addiction

    Directory of Open Access Journals (Sweden)

    Inmaculada Ballesteros-Yáñez

    2018-01-01

    Full Text Available Adenosine receptors (AR are a family of G-protein coupled receptors, comprised of four members, named A1, A2A, A2B, and A3 receptors, found widely distributed in almost all human body tissues and organs. To date, they are known to participate in a large variety of physiopathological responses, which include vasodilation, pain, and inflammation. In particular, in the central nervous system (CNS, adenosine acts as a neuromodulator, exerting different functions depending on the type of AR and consequent cellular signaling involved. In terms of molecular pathways and second messengers involved, A1 and A3 receptors inhibit adenylyl cyclase (AC, through Gi/o proteins, while A2A and A2B receptors stimulate it through Gs proteins. In the CNS, A1 receptors are widely distributed in the cortex, hippocampus, and cerebellum, A2A receptors are localized mainly in the striatum and olfactory bulb, while A2B and A3 receptors are found at low levels of expression. In addition, AR are able to form heteromers, both among themselves (e.g., A1/A2A, as well as with other subtypes (e.g., A2A/D2, opening a whole range of possibilities in the field of the pharmacology of AR. Nowadays, we know that adenosine, by acting on adenosine A1 and A2A receptors, is known to antagonistically modulate dopaminergic neurotransmission and therefore reward systems, being A1 receptors colocalized in heteromeric complexes with D1 receptors, and A2A receptors with D2 receptors. This review documents the present state of knowledge of the contribution of AR, particularly A1 and A2A, to psychostimulants-mediated effects, including locomotor activity, discrimination, seeking and reward, and discuss their therapeutic relevance to psychostimulant addiction. Studies presented in this review reinforce the potential of A1 agonists as an effective strategy to counteract psychostimulant-induced effects. Furthermore, different experimental data support the hypothesis that A2A/D2 heterodimers are

  14. PET imaging of adenosine A2A receptors

    NARCIS (Netherlands)

    Zhou, Xiaoyun

    2017-01-01

    This thesis describes the development and evaluation of [11C]preladenant as a novel radioligand for in vivo imaging of adenosine A2A receptors in the brain with positron-emission tomography (PET). The 11C-labeled drug [11C]preladenant was produced with high radiochemical yield and specific activity.