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Sample records for functional radiotracer studies

  1. Multidrug resistance mediated by ABC transporters in osteosarcoma cell lines: mRNA analysis and functional radiotracer studies

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    Gomes, Celia Maria Freitas [Department of Pathology, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Faculty of Medicine, Institute of Biophysics/Biomathematics, IBILI, 3000-354 Coimbra (Portugal)]. E-mail: cgomes@ibili.uc.pt; van Paassen, Heidi [Department of Pathology, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Romeo, Salvatore [Department of Pathology, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Welling, Mick M. [Department of Radiology, Section of Nuclear Medicine, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Feitsma, R.I.J. [Department of Radiology, Section of Nuclear Medicine, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Abrunhosa, Antero J. [Faculty of Medicine, Institute of Biophysics/Biomathematics, IBILI, 3000-354 Coimbra (Portugal); Botelho, M. Filomena [Faculty of Medicine, Institute of Biophysics/Biomathematics, IBILI, 3000-354 Coimbra (Portugal); Hogendoorn, Pancras C.W. [Department of Pathology, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Pauwels, Ernest [Department of Radiology, Section of Nuclear Medicine, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Cleton-Jansen, Anne Marie [Department of Pathology, Leiden University Medical Center, 2300 RC Leiden (Netherlands)

    2006-10-15

    Drug resistance remains a significant impediment to successful chemotherapy and constitutes a major prognostic factor in osteosarcoma (OS) patients. This study was designed to identify the role and prognostic significance of multidrug-resistance (MDR)-related transporters, such as multidrug resistance protein 1 (MDR1), multidrug-resistance-associated protein (MRP1) and breast-cancer-related protein (BCRP), in OS using cationic lipophilic radiotracers. We evaluated the chemosensitivity of four OS cell lines (Saos-2, 143B, MNNG/HOS and U-2OS) to doxorubicin (DOX), cisplatin (CIS) and methotrexate. The expression of MDR-related transporters was analyzed at mRNA level by quantitative polymerase chain reaction and at functional level by {sup 99m}Tc sestamibi and {sup 99m}Tc tetrofosmin. The effectiveness of MDR modulators [cyclosporin A (CsA) and imatinib] on transporter inhibition and on the reversal of resistance was also assessed. MNNG/HOS and U-2OS cells expressing high levels of MDR1 were highly resistant to DOX and showed reduced accumulation and higher efflux for radiotracers. Although MRP1 was uniformly expressed in all cells, only U-2OS was resistant to CIS. CsA restored sensitivity to DOX and CIS, and enhanced the accumulation and efflux half-life of radiotracers in MDR1-expressing cell lines. The chemosensitivity of OS cells to DOX was strongly dependent on mRNA MDR1 expression and could be circumvented by adding CsA. The kinetic parameters of radiotracers correlated with MDR1 expression levels, hence predicting DOX resistance. We concluded that sensitivity to chemotherapy is strongly dependent on the expression of MDR1 transporter and that radiotracer studies could prove clinically useful in predicting chemotherapy response and in evaluating the efficacy of MDR-reversing agents.

  2. Radiotracers for PET and SPECT studies of neurotransmitter systems

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    Fowler, J.S.

    1991-01-01

    The study of neurotransmitter systems is one of the major thrusts in emission tomography today. The current generation of Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT) radiotracers examines neurotransmitter properties from a number of different perspectives including their pre and post synaptic sites and the activity of the enzymes which regulate their concentration. Although the dopamine system has been the most extensively investigated, other neurotransmitter systems including the acetylcholine muscarine, serotonin, benzodiazepine, opiate, NMDA and others are also under intensive development. Enzymes involved in the synthesis and regulation of neurotransmitter concentration, for example monoamine oxidase and amino acid decarboxylase has also been probed in vivo. Medical applications range from the study of normal function and the characterization of neurotransmitter activity in neurological and psychiatric diseases and in heart disease and cancer to the study of the binding of therapeutic drugs and substances of abuse. This chapter will provide an overview of the current generation of radiotracers for PET and SPECT studies of neurotransmitter systems including radiotracer design, synthesis localization mechanisms and applications in emission tomography. 60 refs., 1 tab.

  3. Biodistribution studies of bee venom and spider toxin using radiotracers

    Directory of Open Access Journals (Sweden)

    C. M. Yonamine

    2005-03-01

    Full Text Available The use of radiotracers allows the understanding of the bioavailability process, biodistribution, and kinetics of any molecule labelled with an isotope, which does not alter the molecule's biological properties. In this work, technetium-99m and iodine-125 were chosen as radiotracers for biodistribution studies in mice using bee (Apis mellifera venom and a toxin (PnTX2-6 from the Brazilian "armed" spider (Phoneutria nigriventer venom. Incorporated radioactivity was measured in the blood, brain, heart, lung, liver, kidney, adrenal gland, spleen, stomach, testicle, intestine, muscle, and thyroid gland. Results provided the blood kinetic parameter, and different organs distribution rates.

  4. MONOAMINE OXIDASE: RADIOTRACER DEVELOPMENT AND HUMAN STUDIES.

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    FOWLER,J.S.; LOGAN,J.; VOLKOW,N.D.; WANG,G.J.; MACGREGOR,R.R.; DING,Y.S.

    2000-09-28

    PET is uniquely capable of providing information on biochemical transformations in the living human body. Although most of the studies of monoamine oxidase (MAO) have focused on measurements in the brain, the role of peripheral MAO as a phase 1 enzyme for the metabolism of drugs and xenobiotics is gaining attention (Strolin Benedetti and Tipton, 1998; Castagnoli et al., 1997.). MAO is well suited for this role because its concentration in organs such as kidneys, liver and digestive organs is high sometimes exceeding that in the brain. Knowledge of the distribution of the MAO subtypes within different organs and different cells is important in determining which substrates (and which drugs and xenobiotics) have access to which MAO subtypes. The highly variable subtype distribution with different species makes human studies even more important. In addition, the deleterious side effects of combining MAO inhibitors with other drugs and with foodstuffs makes it important to know the MAO inhibitory potency of different drugs both in the brain and in peripheral organs (Ulus et al., 2000). Clearly PET can play a role in answering these questions, in drug research and development and in discovering some of the factors which contribute to the highly variable MAO levels in different individuals.

  5. Hydrophilic actinide complexation studied by solvent extraction radiotracer technique

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    Rydberg, J. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Nuclear Chemistry and Radiochemistry Consultant Group, Vaestra Froelunda (Sweden)

    1996-10-01

    Actinide migration in the ground water is enhanced by the formation of water soluble complexes. It is essential to the risk analysis of a wet repository to know the concentration of central atoms and the ligands in the ground water, and the stability of complexes formed between them. Because the chemical behavior at trace concentrations often differ from that at macro concentrations, it is important to know the chemical behavior of actinides at trace concentrations in ground water. One method used for such investigations is the solvent extraction radiotracer (SXRT) technique. This report describes the SXRT technique in some detail. A particular reason for this analysis is the claim that complex formation constants obtained by SXRT are less reliable than results obtained by other techniques. It is true that several difficulties are encountered in the application of SXRT technique to actinide solution, such as redox instability, hydrophilic complexation by side reactions and sorption, but it is also shown that a careful application of the SXRT technique yields results as reliable as by any other technique. The report contains a literature survey on solvent extraction studies of actinide complexes formed in aqueous solutions, particularly by using the organic reagent thenoyltrifluoroacetone (TTA) dissolved in benzene or chloroform. Hydrolysis constants obtained by solvent extraction are listed as well as all actinide complexes studied by SX with inorganic and organic ligands. 116 refs, 11 tabs.

  6. Functional investigation of bone implant viability using radiotracers in a new model of osteonecrosis

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    Luis Schiper

    Full Text Available OBJECTIVES: Conventional imaging methods are excellent for the morphological characterization of the consequences of osteonecrosis; however, only specialized techniques have been considered useful for obtaining functional information. To explore the affinity of radiotracers for severely devascularized bone, a new mouse model of isolated femur implanted in a subcutaneous abdominal pocket was devised. To maintain animal mobility and longevity, the femur was harvested from syngeneic donors. Two technetium-99m-labeled tracers targeting angiogenesis and bone matrix were selected. METHODS: Medronic acid and a homodimer peptide conjugated with RGDfK were radiolabeled with technetium-99m, and biodistribution was evaluated in Swiss mice. The grafted and control femurs were evaluated after 15, 30 and 60 days, including computed tomography (CT and histological analysis. RESULTS: Radiolabeling achieved high (>95% radiochemical purity. The biodistribution confirmed good blood clearance 1 hour after administration. For 99mTc-hydrazinonicotinic acid (HYNIC-E-[c(RGDfK2, remarkable renal excretion was observed compared to 99mTc-methylene diphosphonate (MDP, but the latter, as expected, revealed higher bone uptake. The results obtained in the control femur were equal at all time points. In the implanted femur, 99mTc-HYNIC-E-[c(RGDfK2 uptake was highest after 15 days, consistent with early angiogenesis. Regarding 99mTc-MDP in the implant, similar uptake was documented at all time points, consistent with sustained bone viability; however, the uptake was lower than that detected in the control femur, as confirmed by histology. CONCLUSIONS: 1 Graft viability was successfully diagnosed using radiotracers in severely ischemic bone at all time points. 2 Analogously, indirect information about angiogenesis could be gathered using 999mTc-HYNIC-E-[c(RGDfK2. 3 These techniques appear promising and warrant further studies to determine their potential clinical applications.

  7. Functional investigation of bone implant viability using radiotracers in a new model of osteonecrosis

    Science.gov (United States)

    Schiper, Luis; Faintuch, Bluma Linkowski; da Silva Badaró, Roberto José; de Oliveira, Erica Aparecida; Chavez, Victor E. Arana; Chinen, Elisangela; Faintuch, Joel

    2016-01-01

    OBJECTIVES: Conventional imaging methods are excellent for the morphological characterization of the consequences of osteonecrosis; however, only specialized techniques have been considered useful for obtaining functional information. To explore the affinity of radiotracers for severely devascularized bone, a new mouse model of isolated femur implanted in a subcutaneous abdominal pocket was devised. To maintain animal mobility and longevity, the femur was harvested from syngeneic donors. Two technetium-99m-labeled tracers targeting angiogenesis and bone matrix were selected. METHODS: Medronic acid and a homodimer peptide conjugated with RGDfK were radiolabeled with technetium-99m, and biodistribution was evaluated in Swiss mice. The grafted and control femurs were evaluated after 15, 30 and 60 days, including computed tomography (CT) and histological analysis. RESULTS: Radiolabeling achieved high (>95%) radiochemical purity. The biodistribution confirmed good blood clearance 1 hour after administration. For 99mTc-hydrazinonicotinic acid (HYNIC)-E-[c(RGDfK)2, remarkable renal excretion was observed compared to 99mTc-methylene diphosphonate (MDP), but the latter, as expected, revealed higher bone uptake. The results obtained in the control femur were equal at all time points. In the implanted femur, 99mTc-HYNIC-E-[c(RGDfK)2 uptake was highest after 15 days, consistent with early angiogenesis. Regarding 99mTc-MDP in the implant, similar uptake was documented at all time points, consistent with sustained bone viability; however, the uptake was lower than that detected in the control femur, as confirmed by histology. CONCLUSIONS: 1) Graft viability was successfully diagnosed using radiotracers in severely ischemic bone at all time points. 2) Analogously, indirect information about angiogenesis could be gathered using 999mTc-HYNIC-E-[c(RGDfK)2. 3) These techniques appear promising and warrant further studies to determine their potential clinical applications.

  8. Functional investigation of bone implant viability using radiotracers in a new model of osteonecrosis

    OpenAIRE

    Luis Schiper; Bluma Linkowski Faintuch; Roberto José da Silva Badaró; Erica Aparecida de Oliveira; Arana Chavez, Victor E.; Elisangela Chinen; Joel Faintuch

    2016-01-01

    OBJECTIVES: Conventional imaging methods are excellent for the morphological characterization of the consequences of osteonecrosis; however, only specialized techniques have been considered useful for obtaining functional information. To explore the affinity of radiotracers for severely devascularized bone, a new mouse model of isolated femur implanted in a subcutaneous abdominal pocket was devised. To maintain animal mobility and longevity, the femur was harvested from syngeneic donors. Two ...

  9. A study of residence time distribution using radiotracer technique in the large scale plant facility

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    Wetchagarun, S.; Tippayakul, C.; Petchrak, A.; Sukrod, K.; Khoonkamjorn, P.

    2017-06-01

    As the demand for troubleshooting of large industrial plants increases, radiotracer techniques, which have capability to provide fast, online and effective detections to plant problems, have been continually developed. One of the good potential applications of the radiotracer for troubleshooting in a process plant is the analysis of Residence Time Distribution (RTD). In this paper, the study of RTD in a large scale plant facility using radiotracer technique was presented. The objective of this work is to gain experience on the RTD analysis using radiotracer technique in a “larger than laboratory” scale plant setup which can be comparable to the real industrial application. The experiment was carried out at the sedimentation tank in the water treatment facility of Thailand Institute of Nuclear Technology (Public Organization). Br-82 was selected to use in this work due to its chemical property, its suitable half-life and its on-site availability. NH4Br in the form of aqueous solution was injected into the system as the radiotracer. Six NaI detectors were placed along the pipelines and at the tank in order to determine the RTD of the system. The RTD and the Mean Residence Time (MRT) of the tank was analysed and calculated from the measured data. The experience and knowledge attained from this study is important for extending this technique to be applied to industrial facilities in the future.

  10. Principles of radiotracer methodology

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    Kisieleski, W.E.

    1975-06-01

    Information is presented on the properties of radioisotopes and radiations, methods and equipment for radiation detection, safety in handling radioactive materials, the biological effects of radiation, and the design of radiotracer studies. (LCL)

  11. Radiotracer studies on ion-selective membranes based on poly(vinyl chloride) matrices.

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    Jaber, A M; Moody, G J; Thomas, J D; Willcox, A

    1977-10-01

    Radiotracer studies with (45)Ca, (89)Sr and (133)Ba have provided evidence that the permeation of magnesium, strontium and barium ions through PVC membranes containing Orion 92-20-02 liquid ion-exchanger is inhibited by their low affinity for the liquid ion-exchanger sites. Experiments with (7)Be indicate a strong affinity of the membrane for beryllium ions with corresponding inhibition of permeation. When acid is present in the solution on one side of the membrane, preferential permeation by protons may lead to transport of ions against their concentration gradient in order to maintain the balance of charge.

  12. Evaluation of [18F]MC225 as a PET radiotracer for measuring P-glycoprotein function at the blood-brain barrier in rats: Kinetics, metabolism, and selectivity.

    NARCIS (Netherlands)

    Savolainen, Heli; Windhorst, Albert D.; Elsinga, Philip H.; Cantore, Mariangela; Colabufo, Nicola A.; Willemsen, Antoon T.M.; Luurtsema, Geert

    2016-01-01

    P-glycoprotein is a protective efflux transporter at the blood-brain barrier showing altered function in many neurological disorders. The purpose of this study was to validate [18F]MC225 as a radiotracer for measuring P-glycoprotein function with positron emission tomography. Three groups of Sprague

  13. A radiotracer for In vivo studies of acetylcholinesterase: p-[{sup 18}F]fluorodonepezil

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    Lee, S. Y.; Choi, Y. S.; Choi, Y.; Kim, S. E.; Lee, K. H.; Kim, B. T. [Samsung Medical Center, Seoul (Korea, Republic of); Lee, J. W. [Seoul National Univ., Seoul (Korea, Republic of)

    1999-05-01

    Alzheimer's disease (AD) is one of senile dementia caused by lack of acetylcholine in central nervous system, and in vivo studies of acetylcholinesterase (AChE) have been carried out using many radiolabeled AChE inhibitors (donepezil, tacrine, physostigmine, CP-126,998, etc). Donepezil, a FDA approved drug for AD is now in clinical use. Therefore, we synthesized and evaluated p-[{sup 18}F]fluorodonepezil in mice. Biodistribution studies demonstrated that p-[{sup 18}F]fluorodonepezil binds non-specifically in vivo and does not suffer from metabolism in mouse brain. This study suggests that radioligands with higher binding affinity may be required to visualize AChE in vivo and further studies are needed to develop better radiotracers.

  14. Applications of radiotracer techniques for the pharmacology and toxicology studies of nanomaterials

    Institute of Scientific and Technical Information of China (English)

    ZHANG ZhiYong; ZHAO YuLiang; CHAI ZhiFang

    2009-01-01

    With the rapid development of nanosciences and nanotechnology, a wide variety of manufactured nanomaterials are now used in commodities, pharmaceutics, cosmetics, biomedical products, and in-dustries. While nanomaterials possess more novel and unique physicochemical properties than bulk materials, they also have an unpredictable impact on human health. In the pharmacology and toxicol-ogy studies of nanomaterials, it is essential to know the basic behavior in vivo, i.e. absorption, distri-bution, metabolism, and excretion (ADME) of these newly designed materials. Radiotracer techniques are especially well suited to such studies and have got the chance to demonstrate their enchantment.In this paper, radiolabeling methods for carbon nanomaterials, metallic and metal oxide nanoparticles,etc. are summarized and the applications of the radiolabeled nanomaterials in pharmacology and toxicology studies are outlined.

  15. Radiotracer studies on calcium ion-selective electrode membranes based on poly(vinyl chloride) matrices.

    Science.gov (United States)

    Craggs, A; Moody, G J; Thomas, J D; Willcox, A

    Radiotracer studies with (45)Ca and (36)Cl demonstrate that PVC matrix membranes containing Orion 92-20-02 liquid calcium ion-exchanger are permselective to counter-cations. Diffusion coefficients are quoted for the migration of (45)Ca between pairs of calcium solutions and are discussed in terms of solution concentration, membrane thickness and concentration level of sensor in the membrane. Migration of calcium ions from calcium chloride solution to a Group (II) metal chloride solution through a PVC membrane containing calcium liquid ion-exchanger is discussed in terms of solvent extraction and electrode selectivity coefficient parameters. Thus, magnesium, strontium and barium ions appear to inhibit migration through the membrane by their low affinity for the membrane liquid ion-exchanger sites, while the inhibition by beryllium ions is attributed to site blockage by the strong affinity of dialkylphosphate sites for beryllium.

  16. 2'[(18)F]-fluoroethylrhodamine B is a promising radiotracer to measure P-glycoprotein function.

    Science.gov (United States)

    Trencsényi, György; Kertész, István; Krasznai, Zoárd T; Máté, Gábor; Szalóki, Gábor; Szabó Judit, P; Kárpáti, Levente; Krasznai, Zoltán; Márián, Teréz; Goda, Katalin

    2015-07-10

    In vivo detection of the emergence of P-glycoprotein (Pgp) mediated multidrug resistance in tumors could be beneficial for patients treated with anticancer drugs. PET technique in combination with appropriate radiotracers could be the most convenient method for detection of Pgp function. Rhodamine derivatives are validated fluorescent probes for measurement of mitochondrial membrane potential and also Pgp function. The aim of this study was to investigate whether 2'[(18)F]-fluoroethylrhodamine B ((18)FRB) a halogenated rhodamine derivative previously synthesized for PET assessment of myocardial perfusion preserved its Pgp substrate character. ATPase assay as well as accumulation experiments carried out using Pgp(+) and Pgp(-) human gynecologic (A2780/A2780(AD) and KB-3-1/KB-V1) and a mouse fibroblast cell pairs (NIH 3T3 and NIH 3T3 MDR1) were applied to study the interaction of (18)FRB with Pgp. ATPase assay proved that (18)FRB is a high affinity substrate of Pgp. Pgp(-) cells accumulated the (18)FRB rapidly in accordance with its lipophilic character. Dissipation of the mitochondrial proton gradient by a proton ionophore CCCP decreased the accumulation of rhodamine 123 (R123) and (18)FRB into Pgp(-) cells. Pgp(+) cells exhibited very low R123 and (18)FRB accumulation (around 1-8% of the Pgp(-) cell lines) which was not sensitive to the mitochondrial proton gradient; rather it was increased by the Pgp inhibitor cyclosporine A (CsA). Based on the above data we conclude that (18)FRB is a high affinity Pgp substrate and consequently a potential PET tracer to detect multidrug resistant tumors as well as the function of physiological barriers expressing Pgp.

  17. Challenges in the development of dopamine D2- and D3-selective radiotracers for PET imaging studies.

    Science.gov (United States)

    Mach, Robert H; Luedtke, Robert R

    2017-08-31

    The dopamine D2-like receptors (ie, D2/3 receptors) have been the most extensively studied CNS receptor with Positron Emission Tomography (PET). The 3 different radiotracers that have been used in these studies are [(11) C]raclopride, [(18) F]fallypride, and [(11) C]PHNO. Because these radiotracers have a high affinity for both dopamine D2 and D3 receptors, the density of dopamine receptors in the CNS is reported as the D2/3 binding potential, which reflects a measure of the density of both receptor subtypes. Although the development of D2- and D3-selective PET radiotracers has been an active area of research for many years, this by and large presents an unmet need in the area of translational PET imaging studies. This article discusses some of the challenges that have inhibited progress in this area of research and the current status of the development of subtype selective radiotracers for imaging D3 and D2 dopamine receptors with PET. Copyright © 2017 John Wiley & Sons, Ltd.

  18. An efficient in vitro method for metabolism studies of F-18 labeled radiotracers using mouse liver S9 fraction

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, E. K.; Choi, Y. S.; Kim, D. H.; Ko, B. H.; Lee, K. H.; Choi, Y.; Kim, B. T. [Samsung Medical Center, Seoul (Korea, Republic of)

    2005-07-01

    Metabolism studies are prerequisite for characterization of novel radiotracers. In this study, in vitro metabolism method using mouse liver S9 fraction was established and evaluated using model radiotracers, and the results were compared with those of in vivo method and in vitro method using liver microsomes. 1-(4-[F-18] fluoro methylbenzyl)- ([F-18]1) and 1-(4-[F-18]fluorobenzyl)-4-phen ylpiperazine ([F-18]2) were synthesized and purified by HPLC. Liver S9 fraction and microsomes were prepared from mice. In the in vivo method, mice were injected with the radiotracer, and the bone and blood were collected at 1, 5, 15, 30 and 60 min postinjection. In the in vitro method, the radiotracer was incubated with either S9 fraction or microsomes in the presence of NADPH. The metabolites were analyzed by radio-TLC. Metabolic defluorination was also measured from the incubation of the metabolites with calcium phosphate. [F-18]1 and [F-18]2 were synthesized in 25-35% yield. In the in vivo method, [F-18]1 underwent severe metabolic defluorination based on the increase of bone uptake with time and appearance of [F-18]fluoride ion on radio-TLC in the blood samples. This result was consistent with the in vitro metabolism using either S9 fraction or microsomes, which showed a significant uptake by calcium phosphate. [F-18]2 was converted into unidentified polar metabolites both in vivo and in vitro. There was no increasing uptake by either bone or calcium phosphate with time. The in vitro metabolism of these radiotracers using S9 fraction gave the similar patterns to those using the blood as well as microsomes. This result demonstrated that liver S9 fraction can be used in place of microsomes as well as the blood for the metabolism studies of radiotracers. Moreover, the use of liver S9 fraction has advantages in that it is easily obtained during the early stage of liver microsomal preparation and contains both microsomal and cytosolic fractions.

  19. Injected radiotracer techniques in hydrology

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    Rao, S. M.

    1984-08-01

    Radioactive tracers which have several advantages over conventional tracers made significant contributions to the development of the injected tracer method in hydrology. A review of the nuclear and the physico-chemical characteristics of the possible radiotracer compounds leads us to conclude that the most effective groundwater tracers are tritiated water (HTO),82Br- and58Co or60Co as a hexacyanocobaltate complex. A discussion of the various case studies in India and abroad covering the three groups of applications mentioned helps us to conclude that well established radiotracer methods with associated interpretational techniques are available for many short range studies in surface and subsurface hydrology.

  20. A radiotracer method to study efflux transport of iodide liberated from thyroid hormones via deiodination metabolism in the brain.

    Science.gov (United States)

    Okamura, Toshimitsu; Igarashi, Jun; Kikuchi, Tatsuya; Fukushi, Kiyoshi; Arano, Yasushi; Irie, Toshiaki

    2009-06-05

    Thyroid hormones (TH) play an important role in the development and functional maintenance of the central nervous system. The purpose of this study was to develop a radiotracer method for studying the in vivo efflux transport of iodide liberated by the TH metabolism in the brain. The rationale of our method is as follows: a radioiodinated compound can enter the brain and rapidly release iodide in situ; the iodide efflux rate can be estimated from the clearance of brain radioactivity after disappearance of the iodinated compound. 6-[(125)I]Iodo-9-pentylpurine ([(125)I]9Pe6IP) was designed to enter the brain and release (125)I(-) by the reaction with glutathione and synthesized from the corresponding bromo derivative in a Br/(125)I exchange reaction. The brain kinetics of radioactivity and radioactive metabolites were investigated after intravenous injection of [(125)I]9Pe6IP into mice. The iodide efflux rate was estimated in mice pretreated with perchlorate, an inhibitor of iodide transport from the brain. High brain uptake (5.3% injected dose/g) was observed at 1 min, and almost complete conversion of [(125)I]9Pe6IP to (125)I(-) occurred 10 min after injection. The (125)I(-) uptake from the blood was negligible. (125)I(-) was eliminated from the brain along a single-exponential curve with a half-life of 6.0 min. Furthermore, dose-dependent inhibition of (125)I(-) efflux was observed in mice pretreated with perchlorate. We conclude that 9Pe6IP labeled with (124)I (positron emitter) or (123)I (single-photon emitter) may be useful for studying the in vivo efflux transport of iodide in the brain using nuclear medicine imaging devices.

  1. A philosophy for CNS radiotracer design.

    Science.gov (United States)

    Van de Bittner, Genevieve C; Ricq, Emily L; Hooker, Jacob M

    2014-10-21

    Decades after its discovery, positron emission tomography (PET) remains the premier tool for imaging neurochemistry in living humans. Technological improvements in radiolabeling methods, camera design, and image analysis have kept PET in the forefront. In addition, the use of PET imaging has expanded because researchers have developed new radiotracers that visualize receptors, transporters, enzymes, and other molecular targets within the human brain. However, of the thousands of proteins in the central nervous system (CNS), researchers have successfully imaged fewer than 40 human proteins. To address the critical need for new radiotracers, this Account expounds on the decisions, strategies, and pitfalls of CNS radiotracer development based on our current experience in this area. We discuss the five key components of radiotracer development for human imaging: choosing a biomedical question, selection of a biological target, design of the radiotracer chemical structure, evaluation of candidate radiotracers, and analysis of preclinical imaging. It is particularly important to analyze the market of scientists or companies who might use a new radiotracer and carefully select a relevant biomedical question(s) for that audience. In the selection of a specific biological target, we emphasize how target localization and identity can constrain this process and discuss the optimal target density and affinity ratios needed for binding-based radiotracers. In addition, we discuss various PET test-retest variability requirements for monitoring changes in density, occupancy, or functionality for new radiotracers. In the synthesis of new radiotracer structures, high-throughput, modular syntheses have proved valuable, and these processes provide compounds with sites for late-stage radioisotope installation. As a result, researchers can manage the time constraints associated with the limited half-lives of isotopes. In order to evaluate brain uptake, a number of methods are available

  2. Crystallographic study of PET radiotracers in clinical evaluation for early diagnosis of Alzheimers

    Directory of Open Access Journals (Sweden)

    Angela Altomare

    2014-11-01

    Full Text Available The title compound, C24H25NO3·2CH3OH, which crystallized as a methanol disolvate, has applications as a PET radiotracer in the early diagnosis of Alzheimer's disease. The dihedral angle between the biphenyl rings is 8.2 (2° and the heterocyclic ring adopts a half-chair conformation with the N atom adopting a pyramidal geometry (bond-angle sum = 327.6°. The C atoms of both methoxy groups lie close to the plane of their attached ring [deviations = 0.107 (6 and 0.031 (6 Å]. In the crystal, the components are linked by O—H...O and O—H...N hydrogen bonds, generating [010] chains. C—H...O interactions are also observed.

  3. Radiotracers for medical applications

    Energy Technology Data Exchange (ETDEWEB)

    Rayudu, G.A.S.

    1983-01-01

    This book discusses the medical applications of radiotracers. Diagnostic uses and pharmacokinetics of isotopes and radiopharmaceuticals is emphasized. The volume one covers the following topics: Radiohalogenated compounds, including radioiodine; Tc-labeled compounds; and in-house prepared radiopharmaceuticals. The charge particle range vs. energy in every element is tabulated for protons for cyclotrons users. Discussions are also provided on nonimaging radiotracer methods; /sup 11/C, /sup 13/N, /sup 15/O, /sup 67/Ga. /sup 111/In, /sup 75/Se, /sup 123m/Te compounds; radioactive noble gases; and miscellaneous radiotracers for imaging. Vol. II: Pertinent nuclear science data such as radiation dosimetry, radionuclide production modes, radionuclides for therapy, human experimentation regulations and consent forms, and radiotracer laboratory designs are presented. 272 pp., 7 x 10, 1983, ISBN-0-8493-6016-1.

  4. Efficient Removal of Ce(III and Eu(III Ions from Aqueous Solutions by Local Clay -A Radiotracer Study

    Directory of Open Access Journals (Sweden)

    Som Shankar Dubey

    2011-01-01

    Full Text Available Radiotracer technique has been used to study the removal behavior of Ce(III and Eu(III ions from aqueous solutions by local clay. Adsorptive concentration (10-4–10-6 mol dm-3, pH (ca 2.0-9.0 and temperature (303-333 K were examined for assessing optimal conditions for removal of these ions. The adsorption phenomenon was highly dependent on the amount of the adsorbent concentrations. The uptake of ions, which fitted well for Freundlich isotherm, increased with increase in the temperature and no significant desorption took place in the studied temperature range. The energy of adsorption process for the both cations indicates that the adsorption phenomenon is of chemisorption type. The rate kinetics of the adsorption followed the first order rate kinetics.

  5. Radiotracer method for residence time distribution study in multiphase flow system

    Energy Technology Data Exchange (ETDEWEB)

    Sugiharto, S. [Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Jl. Ganesha 10, Bandung 40132 (Indonesia); Center for the Application of Isotopes and Radiation Technology - National Nuclear Energy Agency, Jl Lebak Bulus No. 49, Jakarta 12440 (Indonesia)], E-mail: sugi@batan.go.id; Su' ud, Z. [Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Jl. Ganesha 10, Bandung 40132 (Indonesia)], E-mail: szaki@fi.itb.ac.id; Kurniadi, R. [Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Jl. Ganesha 10, Bandung 40132 (Indonesia); Wibisono, W.; Abidin, Z. [Center for the Application of Isotopes and Radiation Technology - National Nuclear Energy Agency, Jl Lebak Bulus No. 49, Jakarta 12440 (Indonesia)

    2009-07-15

    [{sup 131}I] isotope in different chemical compounds have been injected into 24 in hydrocarbon transmission pipeline containing approximately 95% water, 3% crude oil, 2% gas and negligible solid material, respectively. The system is operated at the temperature around 70 deg. C enabling fluids flow is easier in the pipeline. The segment of measurement was chosen far from the junction point of the pipeline, therefore, it was reasonably to assume that the fluids in such multiphase system were separated distinctively. Expandable tubing of injector was used to ensure that the isotopes were injected at the proper place in the sense that [{sup 131}I]Na isotope was injected into water layer and iodo-benzene, {sup [131]}IC{sub 6}H{sub 5,} was injected into crude oil regime. The radiotracer selection was based on the compatibility of radiotracer with each of fluids under investigation. [{sup 131}I]Na was used for measuring flow of water while iodo-benzene, {sup [131]}IC{sub 6}H{sub 5,} was used for measuring flow of crude oil. Two scintillation detectors were used and they are put at the distances 80 and 100 m, respectively, from injection point. The residence time distribution data were utilized for calculation water and crude oil flows. Several injections were conducted in the experiments. Although the crude oil density is lighter than the density of water, the result of measurement shows that the water flow is faster than the crude oil flow. As the system is water-dominated, water may act as carrier and the movement of crude oil is slowed due to friction between crude oil with water and crude oil with gas at top layer. Above of all, this result was able to give answer on the question why crude oil always arrives behind water as it is checked at gathering station. In addition, the flow patterns of the water in the pipeline calculated by Reynolds number and predicted by simple tank-in-series model is turbulence in character.

  6. Imaging in hearing using radiotracers

    Directory of Open Access Journals (Sweden)

    Berding Georg

    2017-09-01

    Full Text Available Radiotracers offer unique options for brain imaging of functional and molecular processes related to hearing. Such imaging can be applied in a broad spectrum of situations from preclinical research to clinical patient care. Functional imaging to assess activation in brain regions and networks involved in auditory processing uses markers of blood flow or energy-metabolism in well-defined conditions with and without auditory stimulation. Molecular markers can be used in hearing research for example to study changes in inhibitory neurotransmission systems related to hearing loss. For imaging either positron emission tomography (PET or single-photon emission computed tomography (SPECT are employed. Data analysis can encompasses voxel-wise statistical analysis of activation and calculation of quantitative parameters like receptor binding-potentials based on bio-kinetic modeling. Functional imaging has been frequently used in the context of auditory implantation. Before implantation it aims to assess intactness of the central auditory pathway and prognosis. After implantation it is used to improve understanding of the outcome with respect to auditory function and finally speech understanding, e.g. by measuring correlates of central auditory processing and neuroplasticity.

  7. Preclinical Comparative Study of (68)Ga-Labeled DOTA, NOTA, and HBED-CC Chelated Radiotracers for Targeting PSMA.

    Science.gov (United States)

    Ray Banerjee, Sangeeta; Chen, Zhengping; Pullambhatla, Mrudula; Lisok, Ala; Chen, Jian; Mease, Ronnie C; Pomper, Martin G

    2016-06-15

    (68)Ga-labeled, low-molecular-weight imaging agents that target the prostate-specific membrane antigen (PSMA) are increasingly used clinically to detect prostate and other cancers with positron emission tomography (PET). The goal of this study was to compare the pharmacokinetics of three PSMA-targeted radiotracers: (68)Ga-1, using DOTA-monoamide as the chelating agent; (68)Ga-2, containing the macrocyclic chelating agent p-SCN-Bn-NOTA; and (68)Ga-DKFZ-PSMA-11, currently in clinical trials, which uses the acyclic chelating agent, HBED-CC. The PSMA-targeting scaffold for all three agents utilized a similar Glu-urea-Lys-linker construct. Each radiotracer enabled visualization of PSMA+ PC3 PIP tumor, kidney, and urinary bladder as early as 15 min post-injection using small animal PET/computed tomography (PET/CT). (68)Ga-2 demonstrated the fastest rate of clearance from all tissues in this series and displayed higher uptake in PSMA+ PC3 PIP tumor compared to (68)Ga-1 at 1 h post-injection. There was no significant difference in PSMA+ PC3 PIP tumor uptake for the three agents at 2 and 3 h post-injection. (68)Ga-DKFZ-PSMA-11 demonstrated the highest uptake and retention in normal tissues, including kidney, blood, spleen, and salivary glands and PSMA-negative PC3 flu tumors up to 3 h post-injection. In this preclinical evaluation (68)Ga-2 had the most advantageous characteristics for PSMA-targeted PET imaging.

  8. Novel methodology for the study of mercury methylation and reduction in sediments and water using {sup 197}Hg radiotracer

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro Guevara, Sergio; Perez Catan, Soledad [Centro Atomico Bariloche, Laboratorio de Analisis por Activacion Neutronica, Bariloche (Argentina); Zizek, Suzana; Repinc, Urska; Jacimovic, Radojko; Horvat, Milena [Jozef Stefan Institute, Department of Environmental Sciences, Ljubljana (Slovenia)

    2007-03-15

    Mercury tracers are powerful tools that can be used to study mercury transformations in environmental systems, particularly mercury methylation, demethylation and reduction in sediments and water. However, mercury transformation studies using tracers can be subject to error, especially when used to assess methylation potential. The organic mercury extracted can be as low as 0.01% of the endogenous labeled mercury, and artefacts and contamination present during methylmercury (MeHg) extraction processes can cause interference. Solvent extraction methods based on the use of either KBr/H{sub 2}SO{sub 4} or HCl were evaluated in freshwater sediments using {sup 197}Hg radiotracer. Values obtained for the {sup 197}Hg tracer in the organic phase were up to 25-fold higher when HCl was used, which is due to the coextraction of {sup 197}Hg{sup 2+} into the organic phase during MeHg extraction. Evaluations of the production of MeHg gave similar results with both MeHg extraction procedures, but due to the higher Hg{sup 2+} contamination of the controls, the uncertainty in the determination was higher when HCl was used. The Hg{sup 2+} contamination of controls in the HCl extraction method showed a nonlinear correlation with the humic acid content of sediment pore water. Therefore, use of the KBr/H{sub 2}SO{sub 4} method is recommended, since it is free from these interferences. {sup 197}Hg radiotracer (T{sub 1/2} = 2.673 d) has a production rate that is about 50 times higher than that of {sup 203}Hg (T{sub 1/2} = 46.595 d), the most frequently used mercury radiotracer. Hence it is possible to obtain a similar level of performance to {sup 203}Hg when it is used it in short-term experiments and produced by the irradiation of {sup 196}Hg with thermal neutrons, using mercury targets with the natural isotopic composition. However, if the 0.15% natural abundance of the {sup 196}Hg isotope is increased, the specific activity of the {sup 197}Hg tracer can be significantly improved. In

  9. Novel methodology for the study of mercury methylation and reduction in sediments and water using 197Hg radiotracer.

    Science.gov (United States)

    Ribeiro Guevara, Sergio; Zizek, Suzana; Repinc, Urska; Pérez Catán, Soledad; Jaćimović, Radojko; Horvat, Milena

    2007-03-01

    Mercury tracers are powerful tools that can be used to study mercury transformations in environmental systems, particularly mercury methylation, demethylation and reduction in sediments and water. However, mercury transformation studies using tracers can be subject to error, especially when used to assess methylation potential. The organic mercury extracted can be as low as 0.01% of the endogenous labeled mercury, and artefacts and contamination present during methylmercury (MeHg) extraction processes can cause interference. Solvent extraction methods based on the use of either KBr/H2SO4 or HCl were evaluated in freshwater sediments using 197Hg radiotracer. Values obtained for the 197Hg tracer in the organic phase were up to 25-fold higher when HCl was used, which is due to the coextraction of 197Hg2+ into the organic phase during MeHg extraction. Evaluations of the production of MeHg gave similar results with both MeHg extraction procedures, but due to the higher Hg2+ contamination of the controls, the uncertainty in the determination was higher when HCl was used. The Hg2+ contamination of controls in the HCl extraction method showed a nonlinear correlation with the humic acid content of sediment pore water. Therefore, use of the KBr/H2SO4 method is recommended, since it is free from these interferences. 197Hg radiotracer (T1/2=2.673 d) has a production rate that is about 50 times higher than that of 203Hg (T1/2=46.595 d), the most frequently used mercury radiotracer. Hence it is possible to obtain a similar level of performance to 203Hg when it is used it in short-term experiments and produced by the irradiation of 196Hg with thermal neutrons, using mercury targets with the natural isotopic composition. However, if the 0.15% natural abundance of the 196Hg isotope is increased, the specific activity of the 197Hg tracer can be significantly improved. In the present work, 197Hg tracer was produced from mercury 51.58% enriched in the 196Hg isotope, and a 340-fold

  10. Iodine-124 labelled Annexin-V as a potential radiotracer to study apoptosis using positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Glaser, Matthias E-mail: m.glaser@csc.mrc.ac.uk; Collingridge, D.R.; Aboagye, E.O.; Bouchier-Hayes, Lisa; Hutchinson, O. Clyde; Martin, S.J.; Price, Pat; Brady, Frank; Luthra, S.K

    2003-01-01

    Annexin-V is a calcium-dependent protein that binds with high affinity to phosphaditylserine exposed during apoptosis. The aim of this study was to radiolabel annexin-V with iodine-124 for use as a potential probe of apoptosis by positron emission tomography. Annexin-V was radioiodinated directly using the cyclotron-produced positron emitter iodine-124 by the chloramine-T (CAT) method and indirectly by the pre-labelled reagent N-succinimidyl 3-[{sup 124}I]iodobenzoate ([{sup 124}I]m-SIB). Some reaction parameters of the CAT method such as reaction time and pH were optimised to give radiochemical yields of 22.3{+-}2.6% (n=3, gel-filtration). After incubation with [{sup 124}I]m-SIB, radiolabelled annexin-V was obtained in 14% and 25% yield by FPLC and gel-filtration, respectively. The radiochemical purities from direct and indirect labelling were 97.7{+-}1.0% (n=3) and 96.7{+-}2.1% (n=3), respectively. The new radiotracers could be stored for up to four days without significant de-iodination. The biological activity of radiolabelled annexin-V was tested in control and camptothecin-treated (i.e. apoptotic) human leukaemic HL60 cells. A significantly higher (21%) binding in treated cells was observed with [{sup 125}I]m-SIB-annexin-V. The binding of [{sup 125}I]m-SIB labelled annexin-V to camptothecin treated cells was blocked (68%) by a 100-fold excess of unlabelled annexin-V. Abbreviations: Fast protein liquid chromatography (FPLC), Instant thin layer chromatography (ITLC), Sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE), 3-iodobenzoate (m-IBA), N-succinimidyl 3-(trimethylstannyl)benzoate (m-MeATE)

  11. Applicability and sensitivity of gamma transmission and radiotracer techniques for mineral scaling studies

    Energy Technology Data Exchange (ETDEWEB)

    Bjoernstad, Tor; Stamatakis, Emanuel

    2006-05-15

    Mineral scaling in petroleum and geothermal production systems creates a substantial problem of flow impairment. It is a priority to develop methods for scale inhibition. To study scaling rates and mechanisms in laboratory flow experiments under simulated reservoir conditions two nuclear methods have been introduced and tested. The first applies the principle of gamma transmission to measure mass increase. Here, we use a 30 MBq source of 133Ba. The other method applies radioactive tracers of one or more of the scaling components. We have used the study of CaC03-precipitation, as an example of the applicability of the method where the main tracer used is 47Ca2+. While the first method must be regarded as an indirect method, the latter is a direct method where the reactions of specific components may be studied. Both methods are on-line, continuous and non-destructive, and capable to study scaling of liquids with saturation ratios as low as SR=1.5 or lower. A lower limit of detection for the transmission method in sand-packed columns with otherwise reasonable experimental parameters is less than 1 mg CaC03 in a 1 cm section of the tube packed with silica sand SiO2. A lower limit of detection for the tracer method with reasonable experimental parameters is less than 1 microgram in the same tube section. (author) (tk)

  12. UV-photochemical vapor generation of selenium for atomic absorption spectrometry: Optimization and 75Se radiotracer efficiency study

    Science.gov (United States)

    Rybínová, Marcela; Musil, Stanislav; Červený, Václav; Vobecký, Miloslav; Rychlovský, Petr

    2016-09-01

    Volatile selenium compounds were generated UV-photochemically in the continuous flow mode using four UV-photoreactors differing in the material of the reaction coil; Teflon tubing and quartz tubes with various inner diameters and wall thicknesses were tested. Atomic absorption spectrometry with an externally heated quartz furnace atomizer was employed as the detector. The relevant experimental generation parameters were optimized and the basic analytical characteristics were determined. Using formic acid as the photochemical agent, limits of detection achieved for selenium were in the range 46-102 ng L- 1 in dependence on the type of UV-photoreactor employed. When nitric acid was also added to the photochemical agent, the limits of detection were reduced to 27-44 ng L- 1. The repeatability did not exceed 2.4% (5 μg L- 1 Se(IV), n = 10). Experiments with 75Se radiotracer have been performed for the first time to quantify the efficiency of UV-photochemical vapor generation (UV-PVG) of selenium. The highest efficiency of 67 ± 1% was obtained for a UV-photoreactor containing a quartz reaction coil (2.0 mm i.d., 4.0 mm o.d.). The generation efficiency of 61 ± 1% was obtained for a Teflon reaction coil (1.0 mm i.d., 1.4 mm o.d.). Mapping of the radiotracer distribution in the individual parts of the apparatus did not reveal substantial transport losses of the analyte in the UV-PVG system.

  13. Model studies using supercritical carbon dioxide fluid (SF CO{sub 2}) as a reaction medium for radiotracer synthesis and purification

    Energy Technology Data Exchange (ETDEWEB)

    Ferrieri, R.A.; Fowler, J.S.; Wolf, A.P. [Brookhaven National Lab., Upton, NY (United States)

    1994-05-01

    Supercritical fluids (SFs) have found widespread use in the analytical field as solvents for compound purification, and initial results on their use for radiotracer synthesis have been reported. SF`s possess the unique feature that their solvating strength can be altered drastically through small changes in pressure and temperature of the fluid within the supercritical regime. We have modified a SF chromatograph to allow us to investigate its use in radiotracer synthesis and purification. The solubility of several PET radiotracers was measured in SF CO{sub 2} at 5000 psi and 55{degrees}C and showed the following: raclopride, 68 {mu}g/mL{sup 2}; (L)-deprenyl, 85 {mu}g/mL; flumazenil, 61 {mu}g/mL; (-)cocaine, 108 {mu}g/mL; ritalin, 45 {mu}g/Ml; and cogentin, 250 {mu}g/mL. Analytical separations were achieved on 30 to 50 {mu}g amounts of (L)-deprenyl (3.9 min RT) and nor-deprenyl (4.7 min RT), as well as raclopride (10.8 min RT) and nor-raclopride (10.3 min RT) using 250 mm x 4.5 mm i.d. Ultracarb 5 ODS (30), and 75 mm x 4.5 mm i.d. silica columns, respectively, and pure SF CO{sub 2} as the mobile phase. Model studies on simple N-alkylation reactions were also carried out using pur SF CO{sub 2} as the reaction medium on a modified alumina support. (L)-Deprenyl was synthesized from only 100 {mu}g of the starting labelling substrate using 500 mg of alumina impregnated with triphenylphosphine diiodide (20% by wt.) and maintained at 170{degrees}C. The methylating agent, methyl iodide, was generated in situ from methanol, but was always present in excess of the substrate. Studies are in progress to reduce methanol amounts. Pressure studies of SF CO{sub 2} ranging from 3000 to 6000 psi showed an 80% increase in the methylation reaction relative to the amount of starting substrate suggesting an effect of the fluid density. Temperature was also a critical parameter here as the reaction did not proceed at 80{degrees}C for similiar pressures.

  14. Study of axial mixing, holdup and slip velocity of dispersed phase in a pulsed sieve plate extraction column using radiotracer technique

    Energy Technology Data Exchange (ETDEWEB)

    Ghiyas Ud Din [Department of Nuclear Engineering, Pakistan Institute of Engineering and Applied Sciences -PIEAS, P.O Nilore, Islamabad (Pakistan); Isotope Application Division, Pakistan Institute of Nuclear Science and Technology - PINSTECH, P.O Nilore, Islamabad (Pakistan)], E-mail: fac192@pieas.edu.pk; Imran Rafiq Chughtai; Mansoor Hameed Inayat [Department of Chemical and Materials Engineering, Pakistan Institute of Engineering and Applied Sciences - PIEAS, P.O Nilore, Islamabad (Pakistan); Iqbal Hussain Khan [Isotope Application Division, Pakistan Institute of Nuclear Science and Technology - PINSTECH, P.O Nilore, Islamabad (Pakistan)

    2009-07-15

    Axial mixing, holdup and slip velocity of dispersed phase which are parameters of fundamental importance in the design and operation of liquid-liquid extraction pulsed sieve plate columns have been investigated. Experiments for residence time distribution (RTD) analysis have been carried out for a range of pulsation frequency and amplitude in a liquid-liquid extraction pulsed sieve plate column with water as dispersed and kerosene as continuous phase using radiotracer technique. The column was operated in emulsion region and {sup 99m}Tc in the form of sodium pertechnetate eluted from a {sup 99}Mo/{sup 99m}Tc generator was used to trace the dispersed phase. Axial dispersed plug flow model with open-open boundary condition and two points measurement method was used to simulate the hydrodynamics of dispersed phase. It has been observed that the axial mixing and holdup of dispersed phase increases with increase in pulsation frequency and amplitude until a maximum value is achieved while slip velocity decreases with increase in pulsation frequency and amplitude until it approaches a minimum value. Short lived and low energy radiotracer {sup 99m}Tc in the form of sodium pertechnetate was found to be a good water tracer to study the hydrodynamics of a liquid-liquid extraction pulsed sieve plate column operating with two immiscible liquids, water and kerosene. Axial dispersed plug flow model with open-open boundary condition was found to be a suitable model to describe the hydrodynamics of dispersed phase in the pulsed sieve plate extraction column.

  15. Pharmacokinetic evaluation of the tau PET radiotracer [18F]T807 ([18F]AV-1451) in human subjects.

    Science.gov (United States)

    Wooten, Dustin; Guehl, Nicolas J; Verwer, Eline E; Shoup, Timothy M; Yokell, Daniel L; Zubcevik, Nevena; Vasdev, Neil; Zafonte, Ross D; Johnson, Keith A; El Fakhri, Georges; Normandin, Marc David

    2016-09-22

    [(18)F]T807 is a PET radiotracer developed for imaging tau protein aggregates, which are implicated in neurological disorders including Alzheimer's disease (AD) and traumatic brain injury (TBI). The current study characterizes [(18)F]T807 pharmacokinetics in human subjects using dynamic PET imaging and metabolite-corrected arterial input functions.

  16. Synthesis and evaluation of inhaled [11C]butane and intravenously injected [11C]acetone as potential radiotracers for studying inhalant abuse.

    Science.gov (United States)

    Gerasimov, Madina R; Ferrieri, Richard A; Pareto, Deborah; Logan, Jean; Alexoff, David; Ding, Yu-Shin

    2005-02-01

    The phenomenon of inhalant abuse is a growing problem in the US and many countries around the world. Yet, relatively little is known about the pharmacokinetic properties of inhalants that underlie their abuse potential. While the synthesis of 11C-labeled toluene, acetone and butane has been proposed in the literature, none of these compounds has been developed as radiotracers for PET studies. In the present report we extend our previous studies with [11C]toluene to include [11C]acetone and [11C]butane with the goal of comparing the pharmacokinetic profiles of these three volatile abused substances. Both [11C]toluene and [11C]acetone were administered intravenously and [11C]butane was administered via inhalation to anesthesized baboons. Rapid and efficient uptake of radiolabeled toluene and acetone into the brain was followed by fast clearance in the case of toluene and slower kinetics in the case of acetone. [11C]Butane was detected in the blood and brain following inhalation, but the levels of radioactivity in both tissues dropped to half of the maximal values over the period of less than a minute. To our knowledge, this is the first reported study of the in vivo brain pharmacokinetics of labeled acetone and butane in nonhuman primates. These data provide insight into the pharmacokinetic features possibly associated with the abuse liability of toluene, acetone and butane.

  17. Radiotracers for PETT: new developments and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, J.S.; Wolf, A.P.

    1983-01-01

    Radiotracer development with positron emitters has its major focus on problems in the neurosciences. Progress is reviewed for high-level isotope production and labelled precurser synthesis with the medical cyclotron. The study of regional brain glucose metabolism represented the first extension of one of the methods of neurochemical autoradiography to humans and the study of brain protein synthesis and neurotransmitter receptors followed. In a more general sense, one PETT instrumentation will provide resolution in the 5 mm range is already emerging. Research status is reviewed. 103 references. (PSB)

  18. Radiotracer studies on the uptake of strontium by poly(styrene-DVB) resins containing iminodiacetic acid groups

    Energy Technology Data Exchange (ETDEWEB)

    Samanta, S.K. [Process Development Div., Bhabha Atomic Research Centre, Trombay, Mumbai (India)

    1999-07-01

    The uptake of strontium has been studied using two commercially available chelating resins containing iminodiacetic acid functional groups. The resins have been characterized with respect to moisture content, swelling behaviour, ion exchange and chelating capacities. The effect of pH, sodium and strontium concentrations on the uptake of strontium has been determined by carrying out batch equilibration tests. The suitability of using such a resin for removal of radiostrontium from radioactive waste solutions has also been tested in laboratory-scale column experiments. (orig.)

  19. The Heritage of Radiotracers for PET

    Science.gov (United States)

    Fowler, J. S.; Wolf, A. P.

    1988-05-01

    The history of PET research clearly demonstrates that it is advances in chemistry coupled with a detailed examination of the biochemistry of new radiotracers which has allowed the PET method to be applied to new areas of biology and medicine. Radiotracers whose regional distribution reflects glucose metabolism, neutrotransmitter activity and enzyme activity have all required the development of rapid synthetic methods for the radiotracers themselves and the characterization of their biochemical behavior. This article traces some of the advances in the production of labeled precursors and in radiotracer synthesis and evaluation which have shaped the rapidly expanding application of PET to problems in the neurosciences, in cardiology and in oncology.

  20. Investigation of liquid phase axial dispersion in Taylor bubble flow by radiotracer residence time distribution analysis

    Directory of Open Access Journals (Sweden)

    Jin J.H.

    2013-05-01

    Full Text Available A gas-liquid Taylor bubble flow occurs in small diameter channels in which gas bubbles are separated by slugs of pure liquid. This type of flow regime is well suited for solid catalyzed gas-liquid reactors in which the reaction efficiency is a strong function of axial dispersion in the regions of pure liquid. This paper presents an experimental study of liquid phase axial dispersion in a Taylor bubble flow developed in a horizontal tube using high speed photography and radiotracer residence time distribution (RTD analysis. A parametric dependence of axial dispersion on average volume fraction of gas phase was also investigated by varying the relative volumetric flow rates of the two phases. 137mBa produced from a 137Cs/137mBa radionuclide generator was used as radiotracer and measurements were made using the NaI(Tl scintillation detectors. Validation of 137mBa in the form of barium chloride as aqueous phase radiotracer was also carried out. Axial Dispersion Model (ADM was used to simulate the hydrodynamics of the system and the results of the experiment are presented. It was observed that the system is characterized by very high values of Peclet Number (Pe∼102 which reveals an approaching plug type flow. The experimental and model estimated values of mean residence times were observed in agreement with each other.

  1. Radiotracers in PETT: strategies for in vivo receptor activity, Schizophernia, and Alzheimer's Dementia studies

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, A.P.

    1984-01-01

    Using /sup 18/F-spiperone, a one compartment system with a driving function as model, blocking agents such as butaclamol and ketanserin, assay of the live adult female baboon striatum over the 8 h period, and assay of the parent compound in plasma, it is apparent that residence times in the living tissue and those estimated from in vitro tritium data are at variance. Occupancy rises to a maximum for /sup 18/F benperidol and /sup 18/F haloperidol after approx. 25 minutes and for /sup 18/F spiperone after approx. 75 minutes, but the striatum concentration of /sup 18/F-spiperone and benperiodol remain nearly constant over an eight hour period whereas /sup 18/F haloperidol concentration starts falling almost immediately to half its maximum value at 8 hrs. The best fit to our current data gives a preliminary off rate constant of 0.0057 min/sup -1/.

  2. Preclinical Testing of Novel Radiotracers for Positron Emission Tomography (PET)

    NARCIS (Netherlands)

    van Waarde, Aren; Sijbesma, Jurgen; Doorduin, Janine; Elsinga, Philippus; de Vries, Erik; Glaudemans, Andor; Medema, Jitze; van Zanten, Annie K; Dierckx, Rudi; Ahaus, Cees T B

    2017-01-01

    Preclinical tests of novel radiotracers in experimental animals are required to move tracer candidates from the stage of in vitro testing to the stage of toxicity testing and finally studies in human volunteers. Such preclinical tests are aimed at demonstrating: (1) specific in vivo interaction of

  3. Radiotracer study in a distillation tower with Na-24; Estudio de radiotrazado en una torre de destilacion con Na-24

    Energy Technology Data Exchange (ETDEWEB)

    Vizuet G, J.; Molina, G.; Angeles C, A.; Garcia M, T.; Ruiz C, M. A.; Benitez S, J. A.; Flores M, J., E-mail: Jorge.vizuet@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2013-10-15

    The present summary describes the carried out work of the application of the techniques of gamma profiling in a distillation tower, for the oil industry in Mexico. The study consisted on the application of the gamma profiling technique. An arrangement detector source aligned in a horizontal way was collocated to make a vertical scanning along the tower, in such a way that the signal obtained by this technique allows see the interior of the same one, with the objective of being able to diagnose its operation conditions. According to the applied technique, the height of the signal obtained in the graphs depends on the attenuation of the source radiation, in such a way that if crosses areas of more or small density, the width of the signal decreases or is increased and starting from these results a diagnostic was interpreted. For the profiling service of the distillation tower, Na-24 source and radiation detection equipment coupled to a system of data acquisition was used. Relative to radiological protection a controlled area was defined where the radioactive source was used to avoid unnecessary exhibitions to the plant personnel. Relative to the technique use, in this case stands out the use of Na-24 like source since they required this way the conditions of thickness and diameter of the tower. At the end of the study satisfactory results were obtained. (Author)

  4. Design, synthesis and evaluation of [(3)H]PF-7191, a highly specific nociceptin opioid peptide (NOP) receptor radiotracer for in vivo receptor occupancy (RO) studies.

    Science.gov (United States)

    Zhang, Lei; Drummond, Elena; Brodney, Michael A; Cianfrogna, Julie; Drozda, Susan E; Grimwood, Sarah; Vanase-Frawley, Michelle A; Villalobos, Anabella

    2014-11-15

    Herein we report the identification of (+)-N-(2-((1H-pyrazol-1-yl)methyl)-3-((1R,3r,5S)-6'-fluoro-8-azaspiro[bicyclo[3.2.1]octane-3,1'-isochroman]-8-yl)propyl)-N-[(3)H]-methylacetamide {[(3)H]PF-7191 [(+)-11]} as a promising radiotracer for the nociceptin opioid peptide (NOP) receptor. (+)-11 demonstrated high NOP binding affinity (Ki = 0.1 nM), excellent selectivity over other opioid receptors (>1000×) and good brain permeability in rats (C(b,u)/C(p,u) = 0.29). Subsequent characterization of [(3)H](+)-11 showed a high level of specific binding and a brain bio-distribution pattern consistent with known NOP receptor expression. Furthermore, the in vivo brain binding of [(3)H](+)-11 in rats was inhibited by a selective NOP receptor antagonist in a dose-responsive manner. This overall favorable profile indicated that [(3)H](+)-11 is a robust radiotracer for pre-clinical in vivo receptor occupancy (RO) measurements and a possible substrate for carbon-11 labeling for positron emission tomography (PET) imaging in higher species. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. First ex vivo study demonstrating that {sup 99m}Tc-NTP 15-5 radiotracer binds to human articular cartilage

    Energy Technology Data Exchange (ETDEWEB)

    Cachin, Florent; Culot, Damien [Jean Perrin Cancer Centre, Nuclear Medicine Department, Clermont-Ferrand (France); Universite d' Auvergne, UMR 990 INSERM, Clermont-Ferrand (France); Boisgard, Stephane [Gabriel Montpied University Hospital, Orthopaedic Surgery, Clermont-Ferrand (France); Universite d' Auvergne, UMR 990 INSERM, Clermont-Ferrand (France); Vidal, Aurelien; Auzeloux, Philippe; Madelmont, Jean-Claude; Chezal, Jean-Michel; Miot-Noirault, Elisabeth [Universite d' Auvergne, UMR 990 INSERM, Clermont-Ferrand (France); Filaire, Marc [Universite d' Auvergne, Anatomy Laboratory, Clermont-Ferrand (France); Askienazy, Serge [Cyclopharma Laboratoire, Saint-Beauzire (France)

    2011-11-15

    Preclinical data pointed to {sup 99m}Tc-NTP 15-5 as a good candidate for single photon emission computed tomography (SPECT) imaging of cartilaginous disease. We set out to investigate and quantify {sup 99m}Tc-NTP 15-5 ex vivo uptake by human articular cartilage relative to bone {sup 99m}Tc-hydroxymethylene diphosphonate (HMDP) radiotracer. Three osteoarthritic human tibial plateaux and four tibiofemoral joints were incubated with {sup 99m}Tc-NTP 15-5 and {sup 99m}Tc-HMDP for 2 h. Affinity of tracers for cartilage was determined by visual analysis of SPECT/CT acquisitions and measurement of cartilage to cortical bone uptake ratios. Cartilage to cortical bone uptake ratios were 3.90 {+-} 2.35 and 0.76 {+-} 0.24, respectively, for {sup 99m}Tc-NTP 15-5 and {sup 99m}Tc-HMDP radiotracers. Visual analysis of fused SPECT/CT slices showed selective, intense {sup 99m}Tc-NTP 15-5 accumulation in articular cartilage, whereas {sup 99m}Tc-HMDP binding was low. Interestingly, a cartilage defect visualized on CT was clearly associated with focal decreased uptake of {sup 99m}Tc-NTP 15-5. The tracer {sup 99m}Tc-NTP 15-5 is of major interest for human cartilage molecular imaging and could find clinical applications in osteoarthritis staging and monitoring. (orig.)

  6. PET Radiotracers for Imaging the Proliferation Status of Breast Tumors

    Science.gov (United States)

    2004-12-01

    The mice were implanted in the scapular region 7 days prior to the study. Animals were injected with 100-150 gCi of the "iC-labeled radiotracer and...preparative HPLC using 17.5 % THF/82.5 % of 0.1M ammonium formate (with 0.1% formic acid) buffer at pH = 4.0 as the mobile phase (flow rate = 4.0 mL/min

  7. Diagnosing plant pipeline system performance using radiotracer techniques

    Energy Technology Data Exchange (ETDEWEB)

    Kasban, H.; Ali, Elsayed H.; Arafa, H. [Engineering Department, Nuclear Research Center, Atomic Energy Authority, Inshas (Egypt)

    2017-02-15

    This study presents an experimental work in a petrochemical company for scanning a buried pipeline using Tc{sup 99m} radiotracer based on the measured velocity changes, in order to determine the flow reduction along a pipeline. In this work, Tc{sup 99m} radiotracer was injected into the pipeline and monitored by sodium iodide scintillation detectors located at several positions along the pipeline. The flow velocity has been calculated between every two consecutive detectors along the pipeline. Practically, six experiments have been carried out using two different data acquisition systems, each of them being connected to four detectors. During the fifth experiment, a bypass was discovered between the scanned pipeline and another buried parallel pipeline connected after the injection point. The results indicate that the bypass had a bad effect on the volumetric flow rate in the scanned pipeline.

  8. Radiotracers for SPECT imaging. Current scenario and future prospects

    Energy Technology Data Exchange (ETDEWEB)

    Adak, S.; Vijaya Raj, K.K.; Mandal, S. [GE Healthcare Medical Diagnostics, John F. Welch Technology Center, Bangalore (India).; Bhalla, R.; Pickett, R.; Luthra, S.K. [GE Healthcare Medical Diagnostics, The Grove Centre, Amersham (United Kingdom)

    2012-07-01

    Single photon emission computed tomography (SPECT) has been the cornerstone of nuclear medicine and today it is widely used to detect molecular changes in cardiovascular, neurological and oncological diseases. While SPECT has been available since the 1980s, advances in instrumentation hardware, software and the availability of new radiotracers that are creating a revival in SPECT imaging are reviewed in this paper. The biggest change in the last decade has been the fusion of CT with SPECT, which has improved attenuation correction and image quality. Advances in collimator design, replacement of sodium iodide crystals in the detectors with cadmium zinc telluride (CZT) detectors as well as advances in software and reconstruction algorithms have all helped to retain SPECT as a much needed and used technology. Today, a wide spectrum of radiotracers is available for use in cardiovascular, neurology and oncology applications. The development of several radiotracers for neurological disorders is briefly described in this review, including [{sup 123}I]FP-CIT (DaTSCAN trademark) available for Parkinson's disease. In cardiology, while technetium-99m labeled tetrofosmin and technetium-99m labeled sestamibi have been well known for myocardial perfusion imaging, we describe a recently completed multicenter clinical study on the use of [{sup 123}I]mIBG (AdreView trademark) for imaging in chronic heart failure patients. For oncology, while bone scanning has been prevalent, newer radiotracers that target cancer mechanisms are being developed. Technetium-99m labeled RGD peptides have been reported in the literature that can be used for imaging angiogenesis, while technetium-99m labeled duramycin has been used to image apoptosis. While PET/CT is considered to be the more advanced technology particularly for oncology applications, SPECT continues to be the modality of choice and the workhorse in many hospitals and nuclear medicine centers. The cost of SPECT instruments also

  9. Microleakage Evaluation at Implant-Abutment Interface Using Radiotracer Technique

    Directory of Open Access Journals (Sweden)

    Hakimeh Siadat

    2016-10-01

    Full Text Available Objectives: Microbial leakage through the implant-abutment (I-A interface results in bacterial colonization in two-piece implants. The aim of this study was to compare microleakage rates in three types of Replace abutments namely Snappy, GoldAdapt, and customized ceramic using radiotracing.Materials and Methods: Three groups, one for each abutment type, of five implants and one positive and one negative control were considered (a total of 17 regular body implants. A torque of 35 N/cm was applied to the abutments. The samples were immersed in thallium 201 radioisotope solution for 24 hours to let the radiotracers leak through the I-A interface. Then, gamma photons received from the radiotracers were counted using a gamma counter device. In the next phase, cyclic fatigue loading process was applied followed by the same steps of immersion in the radioactive solution and photon counting.Results: Rate of microleakage significantly increased (P≤0.05 in all three types of abutments (i.e. Snappy, GoldAdapt, and ceramic after cyclic loading. No statistically significant differences were observed between abutment types after cyclic loading.Conclusions: Microleakage significantly increases after cyclic loading in all three Replace abutments (GoldAdapt, Snappy, ceramic. Lowest microleakage before and after cyclic loading was observed in GoldAdapt followed by Snappy and ceramic.Keywords: Dental Implants; Dental Implant-Abutment Design; Thallium Chloride

  10. A Mn-54 Radiotracer Study of Mn Isotope Solid-Liquid Exchange during Reductive Transformation of Vernadite (δ-MnO₂) by Aqueous Mn(II)

    Energy Technology Data Exchange (ETDEWEB)

    Elzinga, Evert J.; Kustka, Adam B. [Rutgers

    2015-04-09

    We employed Mn-54 radiotracers to characterize the extent and dynamics of Mn atom exchange between aqueous Mn(II) and vernadite (δ-Mn(IV)O2) at pH 7.5 under anoxic conditions. Exchange of Mn atoms between the solid and liquid phase is rapid, reaching dynamic equilibrium in 2–4 days. We propose that during the initial stages of reaction, Mn atom exchange occurs through consecutive comproportionation-disproportionation reactions where interfacial electron transfer from adsorbed Mn(II) to lattice Mn(IV) generates labile Mn(III) cations that rapidly disproportionate to reform aqueous Mn(II) and solid-phase Mn(IV). Following nucleation of Mn(III)OOH phases, additional exchange likely occurs through electron transfer from aqueous Mn(II) to solid-phase Mn(III). Our results provide evidence for the fast and extensive production of transient Mn(III) species at the vernadite surface upon contact of this substrate with dissolved Mn(II). We further show that HEPES buffer is a reductant of lattice Mn(IV) in the vernadite structure in our experiments. The methods and results presented here introduce application of Mn-54 tracers as a facile tool to further investigate the formation kinetics of labile Mn(III) surface species and their impacts on Mn-oxide structure and reactivity over a range of environmentally relevant geochemical conditions.

  11. Distributed Microprocessor Automation Network for Synthesizing Radiotracers Used in Positron Emission Tomography [PET

    Science.gov (United States)

    Russell, J. A. G.; Alexoff, D. L.; Wolf, A. P.

    1984-09-01

    This presentation describes an evolving distributed microprocessor network for automating the routine production synthesis of radiotracers used in Positron Emission Tomography. We first present a brief overview of the PET method for measuring biological function, and then outline the general procedure for producing a radiotracer. The paper identifies several reasons for our automating the syntheses of these compounds. There is a description of the distributed microprocessor network architecture chosen and the rationale for that choice. Finally, we speculate about how this network may be exploited to extend the power of the PET method from the large university or National Laboratory to the biomedical research and clinical community at large. (DT)

  12. 用放射性示踪法研究分离铀和铅、铋%A study on the extraction and separation of lead and bismuth from uranium by radiotracer method

    Institute of Scientific and Technical Information of China (English)

    秦芝; 郭俊盛; 甘再国; 马桃桃; 王秀英

    2001-01-01

    用放射性示踪法研究了TBP-苯体系对铀和铅、铋的萃取分离。实验结果表明,在6mol/LHNO3介质中用TBP-苯作为萃取剂可使铀和铅、铋达到定量分离。阴离子交换法对铀进一步纯化后,利用分子电镀法制得厚度为500μg/cm2的233U同位素靶。%The extraction and separation of uranium from lead and bismuthwith TBP-benzene was studied by radiotracer technique. The experimental results demonstrated that using TBP-benzene as an extracting solvent in 6mol/L HNO3 could quantitatively remove the impurities of lead and bismuth from uranium。After purification of uranium, 233U isotopic target with thickness of 500μg/cm2 was obtained by means of molecular electrodeposition.

  13. Radiotracer Imaging of Sediment Columns

    Science.gov (United States)

    Moses, W. W.; O'Neil, J. P.; Boutchko, R.; Nico, P. S.; Druhan, J. L.; Vandehey, N. T.

    2010-12-01

    Nuclear medical PET and SPECT cameras routinely image radioactivity concentration of gamma ray emitting isotopes (PET - 511 keV; SPECT - 75-300 keV). We have used nuclear medical imaging technology to study contaminant transport in sediment columns. Specifically, we use Tc-99m (T1/2 = 6 h, Eγ = 140 keV) and a SPECT camera to image the bacteria mediated reduction of pertechnetate, [Tc(VII)O4]- + Fe(II) → Tc(IV)O2 + Fe(III). A 45 mL bolus of Tc-99m (32 mCi) labeled sodium pertechnetate was infused into a column (35cm x 10cm Ø) containing uranium-contaminated subsurface sediment from the Rifle, CO site. A flow rate of 1.25 ml/min of artificial groundwater was maintained in the column. Using a GE Millennium VG camera, we imaged the column for 12 hours, acquiring 44 frames. As the microbes in the sediment were inactive, we expected most of the iron to be Fe(III). The images were consistent with this hypothesis, and the Tc-99m pertechnetate acted like a conservative tracer. Virtually no binding of the Tc-99m was observed, and while the bolus of activity propagated fairly uniformly through the column, some inhomogeneity attributed to sediment packing was observed. We expect that after augmentation by acetate, the bacteria will metabolically reduce Fe(III) to Fe(II), leading to significant Tc-99m binding. Imaging sediment columns using nuclear medicine techniques has many attractive features. Trace quantities of the radiolabeled compounds are used (micro- to nano- molar) and the half-lives of many of these tracers are short (Image of Tc-99m distribution in a column containing Rifle sediment at four times.

  14. Comparison of two peptide radiotracers for prostate carcinoma targeting

    Directory of Open Access Journals (Sweden)

    Bluma Linkowski Faintuch

    2012-01-01

    Full Text Available OBJECTIVES: Scintigraphy is generally not the first choice treatment for prostate cancer, although successful studies using bombesin analog radiopeptides have been performed. Recently, a novel peptide obtained using a phage display library demonstrated an affinity for prostate tumor cells. The aim of this study was to compare the use of a bombesin analog to that of a phage display library peptide (DUP-1 radiolabeled with technetium-99m for the treatment of prostate carcinoma. The peptides were first conjugated to S-acetyl-MAG3 with a 6-carbon spacer, namely aminohexanoic acid. METHODS: The technetium-99m labeling required a sodium tartrate buffer. Radiochemical evaluation was performed using ITLC and was confirmed by high-performance liquid chromatography. The coefficient partition was determined, and in vitro studies were performed using human prostate tumor cells. Biodistribution was evaluated in healthy animals at various time points and also in mice bearing tumors. RESULTS: The radiochemical purity of both radiotracers was greater than 95%. The DUP-1 tracer was more hydrophilic (log P = -2.41 than the bombesin tracer (log P = -0.39. The biodistribution evaluation confirmed this hydrophilicity by revealing the greater kidney uptake of DUP-1. The bombesin concentration in the pancreas was greater than that of DUP-1 due to specific gastrin-releasing peptide receptors. Bombesin internalization occurred for 78.32% of the total binding in tumor cells. The DUP-1 tracer showed very low binding to tumor cells during the in vitro evaluation, although tumor uptake for both tracers was similar. The tumors were primarily blocked by DUP1 and the bombesin radiotracer primarily targeted the pancreas. CONCLUSION: Further studies with the radiolabeled DUP-1 peptide are recommended. With further structural changes, this molecule could become an efficient alternative tracer for prostate tumor diagnosis.

  15. A method based on Monte Carlo simulations and voxelized anatomical atlases to evaluate and correct uncertainties on radiotracer accumulation quantitation in beta microprobe studies in the rat brain

    Science.gov (United States)

    Pain, F.; Dhenain, M.; Gurden, H.; Routier, A. L.; Lefebvre, F.; Mastrippolito, R.; Lanièce, P.

    2008-10-01

    The β-microprobe is a simple and versatile technique complementary to small animal positron emission tomography (PET). It relies on local measurements of the concentration of positron-labeled molecules. So far, it has been successfully used in anesthetized rats for pharmacokinetics experiments and for the study of brain energetic metabolism. However, the ability of the technique to provide accurate quantitative measurements using 18F, 11C and 15O tracers is likely to suffer from the contribution of 511 keV gamma rays background to the signal and from the contribution of positrons from brain loci surrounding the locus of interest. The aim of the present paper is to provide a method of evaluating several parameters, which are supposed to affect the quantification of recordings performed in vivo with this methodology. We have developed realistic voxelized phantoms of the rat whole body and brain, and used them as input geometries for Monte Carlo simulations of previous β-microprobe reports. In the context of realistic experiments (binding of 11C-Raclopride to D2 dopaminergic receptors in the striatum; local glucose metabolic rate measurement with 18F-FDG and H2O15 blood flow measurements in the somatosensory cortex), we have calculated the detection efficiencies and corresponding contribution of 511 keV gammas from peripheral organs accumulation. We confirmed that the 511 keV gammas background does not impair quantification. To evaluate the contribution of positrons from adjacent structures, we have developed β-Assistant, a program based on a rat brain voxelized atlas and matrices of local detection efficiencies calculated by Monte Carlo simulations for several probe geometries. This program was used to calculate the 'apparent sensitivity' of the probe for each brain structure included in the detection volume. For a given localization of a probe within the brain, this allows us to quantify the different sources of beta signal. Finally, since stereotaxic accuracy is

  16. STUDY ON THE PHYSIOLOGY OF ENVIRONMENT POLLUTION AND THE EFFECT OF HEATING ON THE MALATHION RESIDUE ANALYZED USING THE RADIOTRACER METHOD

    Directory of Open Access Journals (Sweden)

    Razak Achmad Hamzah

    2011-04-01

    Full Text Available The aim of this study is to determine, the comparison of absorption by aquatic plants Hydrilla verticillata and Waterhyacinth (Eichhomia crassipes of malathion insecticide residues in water and comparison of malathion concentrationin tissues of fish fed with of contaminated water plants (Water hyacinth with tissues of fish, which was not fedcontaminated water plant. The effect of heating the contaminated fish tissue, on its level in tissues of rats that consumeit. For the first experiment (aquarium filled with 3 litre of water + H. verticillata 100 gr + Water hyacinth 100 gr + 20uci 14C-labeled malathion; for the second experiment (the first aquarium filled with 3 litre of water + 30 tails ofgoldfish + 20 uci 14C-labeled malathion; second aquarium filled with 3 litre of water + Water hyacinth 100 gr + 30 tailof goldfist + 20 uci 14C –labeled malathion. For the third experiment (most of contaminated fish tissue in the secondexperiment was dried at room temperature and then given to 30 mice and partly heated and then given to another 30mice. Malathion levels were then analyzed by using a liquid scintillation counter LSC-753 (Aloka. The results of alltreatments were compared using the Student t-test. It can be concluded, H. verticillata was more efficient compared tothe enceng gondok in absorbing the insecticide malathion residues in water; malathion concentration in the tissues offish fed Water hyacinth was higher than those of fish not fed Water hyacinth; contaminated fish tissue residues ofmalathion, although be heated, can not be lowered significantly, levels in the tissue.

  17. Long-Circulating and pH-Sensitive Liposome Preparation Trapping a Radiotracer for Inflammation Site Detection.

    Science.gov (United States)

    Mota, Luciene Das Graças; de Barros, André Luís Branco; Fuscaldi, Leonardo Lima; de Oliveira, Mônica Cristina; Cardoso, Valbert Nascimento

    2015-06-01

    Inflammatory and infectious diseases are one of the most common causes of mortality and morbidity. This paper aimed to prepare and to evaluate the ability of long-circulating and pH-sensitive liposomes, trapping a radiotracer, to identify inflamed focus. The physicochemical characterization of freeze-dried liposomes, using glucose as cryoprotectant, showed 80% of the vesicles with adequate mean diameter and good vesicle size homogeneity. Radiotracer encapsulation percentage in liposomes was 10.65%, of which 4.88% was adsorbed on the surface of the vesicles. Furthermore, liposomes presented positive zeta potential. Freeze-dried liposomes, stored for 180 days at 4 degrees C, did not show significant changes in the mean diameter, indicating good stability. Free radiotracer and radiolabeled liposomes were injected into inflammation focus-bearing rats, and ex-vivo biodistribution studies and scintigraphic images were performed. Results showed that radiopharmaceutical, free and encapsulated into liposomes, were able to identify the inflamed site. Target/non-target ratios, obtained by scintigraphic images, were greater than 1.5 at all investigated times. Data did not show significant differences between the free radiotracer and radiolabeled liposomes. Results suggest that this liposomal preparation could be employed as an alternative procedure for inflamed site detection by means of scintigraphic images. However, as the radiotracer is adsorbed onto the liposome surface by electrostatic forces, it is suggested that a neutral radiopharmaceutical be used to confirm the potential of this formulation as a scintigraphic probe for inflammation/infection detection.

  18. Study of water flowrate using time transient and cross-correlation techniques with {sup 82}Br radiotracer; Estudo da vazao da agua utilizando as tecnicas de transiente de tempo e cross-correlacao com 82-Bromine como radiotracador

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, William L., E-mail: william.otero@hotmail.com [Instituto Federal do Rio de Janeiro (IFRJ), Rio de Janeiro, RJ (Brazil); Brandao, Luiz E.B., E-mail: brandao@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    This paper aims to determinate the water flowrate using Time Transient and Cross-Correlation techniques. The detection system uses two NaI (T1) detectors adequately positioned on the outside of pipe and a gamma-ray source ({sup 82}Br radiotracer). The water flowrate measurements using Time Transient and Cross-Correlation techniques were compared to invasive conventional measurements of the flowrate previously installed in pipeline. Discrepancies between Time Transient and Cross-Correlation techniques flowmeter previously installed in pipeline. Discrepancies between Time Transient and Cross-Correlation techniques flowrate values were found to be less than 3% in relation to conventional ones. (author)

  19. Radiotracers For Lipid Signaling Pathways In Biological Systems

    Energy Technology Data Exchange (ETDEWEB)

    Gatley, S. J. [Northeastern Univ., Boston, MA (United States)

    2016-09-26

    The primary focus of this project continues to be the development of radiotracers and radiotracer methodology for studying physiology and biochemistry. The compounds that have been labeled areacylethanolamines and acylglycerols that are, as classes, represented in both in plants and in animals. In the latter, some of these act as ligands for cannabinoid receptors and they are therefore known as endocannabinoids. Cannabinoid receptors are not found in plant genomes so that plants must contain other receptors and signaling systems that use acylethanolamines. Relatively little work has been done on that issue, though acylethanolamines do modulate plant growth and stress resistance, thus possessing obvious relevance to agriculture and energy production. Progress has been described in five peer-reviewed papers and seven meeting abstracts. Preparation of 2-acylglycerol lipid messengers in high purity. A novel enzymatic synthesis was developedthat gave pure 2-acylglycerols free of any rearrrangement to the thermodynamically more stable 1(3)-acylglycerol byproducts. The method utilized 1,3-dibutyryl-2-acylglycerol substrate ethanolysis by a resinimobilized lipase. Thus, pure radiolabeled 2-acylglycerols can now be conveniently prepared just prior to their utilization. These synthetic studies were published in the Journal of Medicinal Chemistry, 2011. Diacylglycerol lipase assay methodology. Diacylglycerol lipases (DAGLs) generate 2- acylglycerols, and are thus potential targets for disease- or growth-modifying agents, by means of reducing formation of 2-acylglycerols. A radioTLC assay of the hydrolysis of radiolabeled diglyceride substrate [1''-carbon-14]2-arachidonoyl-1-stearoyl-sn-glycerol has been implemented, and used to validate a novel, potentially highthroughput fluorescence resonance energy transfer (FRET) based assay. A number of new DAGL inhibitors that have selectivity for DAGLs were synthesized and screened. This work was very recently published in

  20. In situ lithium diffusion measurement in solid ionic conductors using short-lived radiotracer beam of {sup 8}Li

    Energy Technology Data Exchange (ETDEWEB)

    Ishiyama, H. [Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Jeong, S.C., E-mail: sunchan.jeong@kek.jp [Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Watanabe, Y.X.; Hirayama, Y.; Imai, N.; Miyatake, H.; Oyaizu, M. [Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Osa, A.; Otokawa, Y.; Matsuda, M.; Nishio, K.; Makii, H.; Sato, T.K. [Japan Atomic Energy Agency (JAEA), Shirane 2-4, Tokai, Ibaraki 319-1195 (Japan); Kuwata, N.; Kawamura, J. [Institute of Multidisciplinary Research for Advance Materials, Tohoku University, Sendai 980-8577 (Japan); Nakao, A.; Ueno, H. [Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan); Kim, Y.H. [Seoul National University, Gwanak-ro, Gwanak-gu, Seoul 151-747 (Korea, Republic of); Kimura, S.; Mukai, M. [University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan)

    2015-07-01

    We developed an in situ radiotracer method for diffusion studies in solids using short-lived α-emitting {sup 8}Li tracer. In the method, while implanting a pulsed {sup 8}Li beam into a solid material of interest, the α particles emitted into the implantation side of the sample surface were detected as a function of time. By changing the implantation depth and the detection angle against the sample surface according to lithium diffusivity (deep implantation and large angle with a large solid angle, or shallow implantation and small angle with a narrow solid angle), the method can be sensitive to a wide range of diffusion length ranging from micrometer scale to nanometer scale per second. The feasibility of the method was demonstrated by measuring the lithium diffusion coefficients to the order of 10{sup −12} cm{sup 2}/s in lithium ionic conductors.

  1. Prediction of Separation Length of Turbulent Multiphase Flow Using Radiotracer and Computational Fluid Dynamics Simulation

    Directory of Open Access Journals (Sweden)

    S. Sugiharto1

    2013-04-01

    Full Text Available Multiphase flow modeling presents great challenges due to its extreme importance in various industrial and environmental applications. In the present study, prediction of separation length of multiphase flow is examined experimentally by injection of two kinds of iodine-based radiotracer solutions into a hydrocarbon transport pipeline (HCT having an inner diameter of 24 in (60,96 m. The main components of fluids in the pipeline are water 95%, crude oil 3% and gas 2%. A radiotracing experiment was carried out at the segment of pipe which is located far from branch points with assumptions that stratified flows in such segment were achieved. Two radiation detectors located at 80 and 100 m from injection point were used to generate residence time distribution (RTD curve resulting from injection of radiotracer solutions. Multiphase computational fluid dynamics (CFD simulations using Eulerian-Eulerian control volume and commercial CFD package Fluent 6.2 were employed to simulate separation length of multiphase flow. The results of study shows that the flow velocity of water is higher than the flow rate of crude oil in water-dominated system despite the higher density of water than the density of the crude oil. The separation length in multiphase flow predicted by Fluent mixture model is approximately 20 m, measured from injection point. This result confirms that the placement of the first radiation detector at the distance 80 m from the injection point was correct

  2. The uses of radiotracers in the life sciences

    Science.gov (United States)

    Ruth, Thomas J.

    2009-01-01

    Radionuclides have been used to follow physical, chemical and biological processes almost from the time of their discovery. Probably the application with the biggest impact has been in the medical field where radionuclides have been incorporated into biologically active molecules and used to diagnose a wide variety of diseases and to treat many disorders. Other uses in the life sciences, in general, are related to using a radioactive isotope as marker for an existing species such as nitrogen-13 in plant studies or copper-67 to track copper catalysts in phytoplankton. This review describes in general terms these uses as well as providing the reader with the background related to the physical properties of radioactive decay, the concepts associated with the production of radionuclides using reactors or accelerators and the fundamentals of imaging radioactivity. The advances in imaging technology in recent years has had a profound impact on the use of radionuclides in positron emission tomography and the coupling of other imaging modalities to provide very precise insights into human disease. The variety of uses for radiotracers in science is almost boundless dependent only upon ones imagination.

  3. Accumulation of 99m TC-methylene diphosphonate radiotracer in ...

    African Journals Online (AJOL)

    Accumulation of 99m TC-methylene diphosphonate radiotracer in rat's forelimb. ... by gamma camera 2 h after the injection of 99mTc-MDP via the tail vein. ... can be used for survey radioactivity examination in different bones of the forelimb.

  4. The Expanding Reach of Environmental Radiotracers - New Chronometers And More Sensitive Measurements

    Science.gov (United States)

    Aalseth, C.

    2015-12-01

    Radiotracers in the environment provide powerful tools for understanding environmental processes. Viewed as an age continuum, methods using shorter-lived radionuclides (1,000 y) like 10Be, 14C, 36Cl, and 81Kr generally rely on atom-counting measurements such as accelerator mass spectrometry. Significant challenges exist in the age range between 100 and 1,000 years where useful radiotracers are difficult to measure by either method and can have very low abundance. These challenges are being addressed with more sensitive measurements using both atom counting and radioactive decay, extending the reach of established radiotracers as well as adding new chronometers. Improvements in atom-counting methods will be reviewed; the practicality of using 81Kr (abundance ~5×10-13 in atmospheric krypton) for age-dating old aquifers has been established and current work focuses on improving sample utilization efficiency to allow smaller samples to be measured. Better efficiency also brings lower-abundance isotopes within reach, for example 39Ar. Improvements in radioactive decay counting will be reviewed; these take advantage of ultra-pure materials to achieve lower backgrounds and are adding new age-dating reach to the environmental science tool-set with intermediate half-life radionuclides, for example 32Si for sediment cores. These methods also improve sensitivity for established radiotracers like 3H and will allow smaller samples to be measured, allowing specific processes to be traced. For example, using 3H as an indicator of carbon cycling through organic compounds in soil systems. Progress in both atom counting and decay counting is expanding the use of 39Ar for age-dating aquifers, measuring ocean mixing, and age-dating younger glacial ice. Argon-39 is a challenging intermediate-age radiotracer (269-year half-life) with low abundance (~8×10-16 in atmospheric argon). New decay counting capabilities have expanded worldwide capacity for 39Ar aquifer measurements, while

  5. Receptor-binding radiotracers: a class of potential radiopharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    Eckelman, W.C.; Reba, R.C.; Gibson, R.E.; Rzeszotarski, W.J.; Vieras, F.; Mazaitis, J.K.; Francis, B.

    1979-04-01

    To date no radiopharmaceutical is routinely used to study changes in receptor concentration. Frequently changes in receptor concentration, or the appearance of receptors in tumors, indicates a specific pathologic state. With a receptor-binding radiotracer, in vivo studies of these changes will be possible. A reversible bimolecular model and in vitro tests were used to determine equilibrium constants and maximal target-to-blood ratios for new derivatives. Theoretical calculations showed that derivatives binding to the estrogen receptor, the beta adrenoceptor, or the cholinergic receptor are capable of achieving satisfactory target-to-blood ratios. Using in vitro tests, the apparent affinity constant was determined for five iodinated estrogen derivatives and five derivatives of beta blockers. Results of the in vitro study with derivatives of beta blockers. Results of the in vitro study with derivatives of beta blockers, and in vivo displacement studies using propranolol, indicated that the high heart-to-blood ratios (5 to 20) obtained with the new derivatives were not the result of a specific interaction with the receptor. In this instance factors other than receptor binding control the in vivo distribution. The in vitro assay using estrogen receptors showed that of the five derivatives, iodohexestrol and 17-alpha-iodoethynylestradiol bind to the receptor with the highest affinity. In vivo studies confirmed these results; iodohexestrol gave a uterus-to-blood ratio of 10 in immature rats when plasma-protein binding was blocked. With a tritiated muscarinic cholinergic blocking agent, heart-to-blood ratios near the theoretical maximum were obtained. This compound most closely follows the mechanism described by the model. Use of the theoretical model in conjunction with in vitro assays can greatly aid in the design of this new class of receptor-binding radiopharmaceuticals.

  6. Radiotracers For Lipid Signaling Pathways In Biological Systems

    Energy Technology Data Exchange (ETDEWEB)

    Gatley, S. J. [Northeastern Univ., Boston, MA (United States)

    2016-09-26

    The primary focus of this project continues to be the development of radiotracers and radiotracer methodology for studying physiology and biochemistry. The compounds that have been labeled areacylethanolamines and acylglycerols that are, as classes, represented in both in plants and in animals. In the latter, some of these act as ligands for cannabinoid receptors and they are therefore known as endocannabinoids. Cannabinoid receptors are not found in plant genomes so that plants must contain other receptors and signaling systems that use acylethanolamines. Relatively little work has been done on that issue, though acylethanolamines do modulate plant growth and stress resistance, thus possessing obvious relevance to agriculture and energy production. Progress has been described in five peer-reviewed papers and seven meeting abstracts. Preparation of 2-acylglycerol lipid messengers in high purity. A novel enzymatic synthesis was developedthat gave pure 2-acylglycerols free of any rearrrangement to the thermodynamically more stable 1(3)-acylglycerol byproducts. The method utilized 1,3-dibutyryl-2-acylglycerol substrate ethanolysis by a resinimobilized lipase. Thus, pure radiolabeled 2-acylglycerols can now be conveniently prepared just prior to their utilization. These synthetic studies were published in the Journal of Medicinal Chemistry, 2011. Diacylglycerol lipase assay methodology. Diacylglycerol lipases (DAGLs) generate 2- acylglycerols, and are thus potential targets for disease- or growth-modifying agents, by means of reducing formation of 2-acylglycerols. A radioTLC assay of the hydrolysis of radiolabeled diglyceride substrate [1''-carbon-14]2-arachidonoyl-1-stearoyl-sn-glycerol has been implemented, and used to validate a novel, potentially highthroughput fluorescence resonance energy transfer (FRET) based assay. A number of new DAGL inhibitors that have selectivity for DAGLs were synthesized and screened. This work was very recently published in

  7. Biosorptive behaviour of Mango (Mangifera indica) and Neem (Azadirachta indica) bark for Hg{sup 2+}, Cr{sup 3+} and Cd{sup 2+} toxic ions from aqueous solutions: a radiotracer study

    Energy Technology Data Exchange (ETDEWEB)

    Tiwari, Diwakar; Mishra, Shuddhodan P. [Nuclear and Radiochemistry Laboratory, Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi (India); Mishra, Manisha; Dubey, R.S. [Department of Biochemistry, Faculty of Science, Banaras Hindu University, Varanasi (India)

    1999-04-01

    Biosorption of Hg{sup 2+} and Cr{sup 3+} on dead biomass Mango (Mangifera indica) and Neem (Azadirachta indica) bark has been assessed at micro to tracer level concentrations from aqueous solutions employing the 'radiotracer technique'. A high level of uptake of metal ions on these solid surfaces occurs within ca. 4 h of contact time reaching apparent saturation. The increase of sorptive concentration (10{sup -8} to 10{sup -2} mol dm{sup -3}), temperature (293-323 K) and pH (ca. 3 to 10) favoured the removal process of these ions; but in the case of Hg{sup 2+} on Neem bark, there was seemingly no temperature effect. The uptake process follows first order rate law and obeys the Freundlich adsorption isotherm. Added anions and cations in the bulk solution inhibit to some extent the removal of these toxic ions. Similarly the inhibition in the uptake was also observed when both biomasses were irradiated by neutron and {gamma}-rays prior to being employed as sorbents. No significant sorption of Cd{sup 2+} was observed on these dead biomass solid surfaces under various physical-chemical conditions.

  8. Ultrasonography of the testis: correlation with radiotracer perfusion. [/sup 99m/Tc-pertechnetate

    Energy Technology Data Exchange (ETDEWEB)

    Winston, M.A.; Handler, S.J.; Pritchard, J.H.

    1978-06-01

    Ultrasonic study of testicular disease and paratesticular masses was carried out in 20 cases. In eight of these comparison was made with pertechnetate perfusion studies performed concurrently. Testicular torsion was well revealed by both techniques. Acute orchitis, in the early stages, was shown more clearly by radiotracer, unless there was associated epididymal swelling or hydrocele. Chronic complications of inflammation, particularly abscess formation, were seen best by ultrasonography. Paratesticular masses could be studied only by ultrasound. These included both solid and cystic masses due to chronic epididymitis.

  9. Prediction of water vapor transport rates across polyvinylchloride packaging systems using a novel radiotracer method

    Energy Technology Data Exchange (ETDEWEB)

    Wood, R.W.; Mulski, M.J.; Kuu, W.Y. (Baxter Healthcare Corporation, Round Lake, IL (USA))

    1990-09-01

    A radiotracer method is used to study the transport properties of water vapor in polyvinylchloride (PVC), a plastic commonly used in the packaging of parenteral solutions. Water vapor transport across a PVC film appears to be Fickian in nature. Using the steady-state solution of Fick's second law and the permeability coefficient of water vapor across the PVC film obtained using the described method, the predicted water vapor transport rate (WVTR) for a parenteral solution packaged in PVC is in reasonable agreement with actual WVTR as determined by weight loss under precisely controlled conditions.

  10. Cross-Coupling Reactions as Valuable Tool for the Preparation of PET Radiotracers

    Directory of Open Access Journals (Sweden)

    Marc Pretze

    2011-01-01

    Full Text Available The increasing application of positron emission tomography (PET in nuclear medicine has stimulated the extensive development of a multitude of new radiotracers and novel radiolabeling procedures with the most prominent short-lived positron emitters carbon-11 and fluorine-18. Radiolabeling with these radionuclides represents a remarkable challenge. Special attention has to be paid to synthesis time and specific labeling techniques due to the short physical half life of the respective radionuclides 11C (t1/2 = 20.4 min and 18F (t1/2 = 109.8 min. In the past, numerous transition metal-catalyzed reactions were employed in organic chemistry, even though only a handful of these coupling reactions were adopted in radiochemical practice. Thus, the implementation of modern synthesis methods like cross-coupling reactions offers the possibility to develop a wide variety of novel radiotracers. The introduction of catalysts based on transition metal complexes bears a high potential for rapid, efficient, highly selective and functional group-tolerating incorporation of carbon-11 and fluorine-18 into target molecules. This review deals with design, application and improvement of transition metal-mediated carbon-carbon as well as carbon-heteroatom cross-coupling reactions as a labeling feature with the focus on the preparation of radiolabeled compounds for molecular imaging.

  11. Non-invasive radiotracer imaging as a tool for drug development.

    Science.gov (United States)

    Gibson, R E; Burns, H D; Hamill, T G; Eng, W S; Francis, B E; Ryan, C

    2000-07-01

    Non-Invasive Radiotracer Imaging (NIRI) uses either short-lived positron-emitting isotopes, such as 11C and 18F, for Positron Emis ion Tomography (PET) or single photon emitting nuclides, e.g., 123I, which provide images using planar imaging or Single-Photon Emission Computed Tomography (SPECT). These high-resolution imaging modalities provide anatomical distribution and localization of radiolabeled drugs, which can be used to generate real time receptor occupancy and off-rate studies in humans. This can be accomplished by either isotopically labeling a potential new drug (usually with 11C), or indirectly by studying how the unlabelled drug inhibits specific radioligand binding in vivo. Competitive blockade studies can be accomplished using a radiolabeled analogue which binds to the site of interest, rather than a radiolabeled version of the potential drug. Imaging, particularly PET imaging, can be used to demonstrate the effect of a drug through a biochemical marker of processes such as glucose metabolism or blood flow. NIRI as a development tool in the pharmaceutical industry is gaining increased acceptance as its unique ability to provide such critical information in human subjects is recognized. This section will review recent examples that illustrate the utility of NIRI, principally PET, in drug development, and the potential of imaging advances in the development of cancer drugs and gene therapy. Finally, we provide a brief overview of the design of new radiotracers for novel targets.

  12. Chemistry and biology of radiotracers that target changes in sympathetic and parasympathetic nervous systems in heart disease.

    Science.gov (United States)

    Eckelman, William C; Dilsizian, Vasken

    2015-06-01

    Following the discovery of the sympathetic and parasympathetic nervous system, numerous adrenoceptor drugs were radiolabeled and potent radioligands were prepared in order to image the β-adrenergic and the muscarinic systems. But the greatest effort has been in preparing noradrenaline analogs, such as norepinephrine, (11)C-metahydroxyephedrine, and (123)I-metaiodobenzylguanidine that measure cardiac sympathetic nerve varicosities. Given the technical and clinical challenges in designing and validating targeted adrenoceptor-binding radiotracers, namely the heavily weighted flow dependence and relatively low target-to-background ratio, both requiring complicated mathematic analysis, and the inability of targeted adrenoceptor radioligands to have an impact on clinical care of heart disease, the emphasis has been on radioligands monitoring the norepinephrine pathway. The chemistry and biology of such radiotracers, and the clinical and prognostic impact of these innervation imaging studies in patients with heart disease, are examined. © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

  13. Establishment of a trimodality analytical platform for tracing, imaging and quantification of gold nanoparticles in animals by radiotracer techniques.

    Science.gov (United States)

    Chen, Chien-Hung; Lin, Fong-Sian; Liao, Wei-Neng; Liang, Sanching L; Chen, Min-Hua; Chen, Yo-Wen; Lin, Wan-Yu; Hsu, Ming-Hua; Wang, Mei-Ya; Peir, Jinn-Jer; Chou, Fong-In; Chen, Ching-Ya; Chen, Sih-Yu; Huang, Su-Chin; Yang, Mo-Hsiung; Hueng, Dueng-Yuan; Hwu, Yeukuang; Yang, Chung-Shi; Chen, Jen-Kun

    2015-01-06

    This study aims to establish a (198)Au-radiotracer technique for in vivo tracing, rapid quantification, and ex vivo visualization of PEGylated gold nanoparticles (GNPs) in animals, organs and tissue dissections. The advantages of GNPs lie in its superior optical property, biocompatibility and versatile conjugation chemistry, which are promising to develop diagnostic probes and drug delivery systems. (198)Au is used as a radiotracer because it simultaneously emits beta and gamma radiations with proper energy and half-life; therefore, (198)Au can be used for bioanalytical purposes. The (198)Au-tagged radioactive gold nanoparticles ((198)Au-GNPs) were prepared simply by irradiating the GNPs in a nuclear reactor through the (197)Au(n,γ)(198)Au reaction and subsequently the (198)Au-GNPs were subjected to surface modification with polyethylene glycol to form PEGylated (198)Au-GNPs. The (198)Au-GNPs retained physicochemical properties that were the same as those of GNP before neutron irradiation. Pharmacokinetic and biodisposition studies were performed by intravenously injecting three types of (198)Au-GNPs with or without PEGylation into mice; the γ radiation in blood specimens and dissected organs was then measured. The (198)Au-radiotracer technique enables rapid quantification freed from tedious sample preparation and shows more than 95% recovery of injected GNPs. Clinical gamma scintigraphy was proved feasible to explore spatial- and temporal-resolved biodisposition of (198)Au-GNPs in living animals. Moreover, autoradiography, which recorded beta particles from (198)Au, enabled visualizing the heterogeneous biodisposition of (198)Au-GNPs in different microenvironments and tissues. In this study, the (198)Au-radiotracer technique facilitated creating a trimodality analytical platform for tracing, quantifying and imaging GNPs in animals.

  14. In-vivo imaging characteristics of two fluorinated flumazenil radiotracers in the rat

    Energy Technology Data Exchange (ETDEWEB)

    Dedeurwaerdere, Stefanie [University of Melbourne, Department of Medicine (RMH), Parkville, VIC (Australia); ANSTO, Radiopharmaceuticals Research Institute, Sydney (Australia); Gregoire, Marie-Claude; Fookes, Christopher; Greguric, Ivan; Pham, Tien; Loc' h, Christian; Katsifis, Andrew [ANSTO, Radiopharmaceuticals Research Institute, Sydney (Australia); Vivash, Lucy; O' Brien, Terence J.; Myers, Damian E. [University of Melbourne, Department of Medicine (RMH), Parkville, VIC (Australia); Roselt, Peter; Binns, David; Hicks, Rodney J. [Peter MacCallum Cancer Centre, Centre for Molecular Imaging, Melbourne (Australia)

    2009-06-15

    [{sup 11}C]Flumazenil shows promise as a clinical and research PET radiotracer to image changes in GABA{sub A} central benzodiazepine receptor (cBZR), but its widespread use has been limited by practical limitations of [{sup 11}C]. This study evaluated the imaging characteristics of two fluorinated PET radiotracers in rats in vivo: [{sup 18}F]fluoroflumazenil ([{sup 18}F]FFMZ) and [{sup 18}F]flumazenil ([{sup 18}F]FMZ). PET acquisitions were performed on a small-animal scanner following injection of [{sup 18}F]FFMZ in nine rats and [{sup 18}F]FMZ in eight rats. The following treatments were investigated: (1) injection of the tracer dose, (2) presaturation then injection of the tracer dose, and (3) injection of the tracer dose followed by a displacement injection. Unchanged tracer was measured in plasma and brain structures in four animals 10 and 30 min after injection, and ex-vivo autoradiography was also performed. For both [{sup 18}F]FFMZ and [{sup 18}F]FMZ maximal brain activity peaked rapidly, and was highest in the hippocampus (1.12{+-}0.06 SUV, 1.24{+-}0.10 SUV, respectively), and lowest in the pons (1.00{+-}0.07 SUV, 1.03{+-}0.09 SUV, respectively). By 50 min after injection, maximal uptake for [{sup 18}F]FFMZ and [{sup 18}F]FMZ had decreased in the hippocampus to 18{+-}3% and 80{+-}1% (p<0.01), respectively. The presaturation and displacement studies showed a higher nonspecific component for [{sup 18}F]FFMZ than for [{sup 18}F]FMZ. Metabolite studies showed that at 30 min only 10% of the signal was from [{sup 18}F]FFMZ in the brain. This nonspecific binding was apparent on autoradiography. In contrast, [{sup 18}F]FMZ accounted for >70% of the signal in the brain, which resulted in well-defined regional binding on autoradiography. These results demonstrate that [{sup 18}F]FMZ is a superior radiotracer to [{sup 18}F]FFMZ for in-vivo PET imaging of the GABA{sub A}/cBZR, having slower metabolism and leading to lower concentrations of metabolites in the brain

  15. Nuclear emission-based imaging in the study of brain function

    Science.gov (United States)

    Sossi, Vesna

    2016-09-01

    Nuclear emission - based imaging has been used in medicine for decades either in the form of Single Photon Emission Computerized Tomography (SPECT) or Positron Emission Tomography (PET). Both techniques are based on radiolabelling molecules of biological interest (radiotracers) with either a gamma (SPECT) or a positron (PET) emitting radionuclide. By detecting radiation from the radiolabels and reconstructing the acquired data it is possible to form an image of the radiotracer distribution in the body and thus obtain information on the biological process that the radiotracer is tagging. While most of the clinical applications of PET are in oncology, where the glucose analogue 18F-flurodeoxyglocose (FDG) is the most commonly used radiotracer, the importance of PET imaging for brain applications is rapidly increasing. Numerous radiotracers exist that can tag different neurotransmitter systems as well as abnormal protein aggregations that are known to underlie several brain diseases: amyloid deposition, a characteristic of Alzheimer's, and, more recently, tau deposition, which is deemed abnormal not only in dementia, but also in Parkinson's syndrome and traumatic brain injury. Imaging has shown that may brain diseases start decades before clinical symptoms, in part explaining the difficulty of developing adequate treatments. This talk will briefly summarize the role of PET imaging in the study of neurodegeneration and discuss the upcoming hybrid PET/MRI imaging instrumentation. NSERC, CIHR, MJFF.

  16. Experimental observation of silver and gold penetration into dental ceramic by means of a radiotracer technique

    Energy Technology Data Exchange (ETDEWEB)

    Moya, F.; Payan, J.; Bernardini, J.; Moya, E.G.

    1987-12-01

    A radiotracer technique was used to study silver and gold diffusion into dental porcelain under experimental conditions close to the real conditions in prosthetic laboratories for porcelain bakes. It was clearly shown that these non-oxidizable elements were able to diffuse into the ceramic as well as oxidizable ones. The penetration depth varied widely according to the element. The ratio DAg/DAu was about 10(3) around 850 degrees C. In contrast to gold, the silver diffusion rate was high enough to allow silver, from the metallic alloy, to be present at the external ceramic surface after diffusion into the ceramic. Hence, the greening of dental porcelains baked on silver-rich alloys could be explained mainly by a solid-state diffusion mechanism.

  17. Radiotracer diffusion in semiconductors and metallic compounds using short-lived isotopes

    CERN Multimedia

    Deicher, M; Kronenberg, J; Wagner, F E

    The transport of atoms in solids is of central importance for solid state physics, chemistry, metallurgy, and material sciences. Since the mobility of atoms in solids contributes to many physical phenomena the study of diffusion processes is of fundamental interest for solid state physics. Diffusion processes were frequently investigated using radioactive isotopes (radiotracers). The application of short-lived isotopes delivered at ISOLDE extends substantially the possibilities of investigating diffusion processes in solids. In particular, a new experimental set-up to be installed at ISOLDE in this year will enable the use of radioactive isotopes with half-lives down to minutes. Alternatively, in special cases diffusion processes can be investigated with help of hyperfine techniques on an atomic scale, like by perturbed $\\gamma \\gamma$-angular correlation (PAC). Here, the motion of the atom of interest becomes visible directly via characteristic changes in the measured PAC spectra.

  18. Radiotracer evaluation of laterite and coal-ash dust discharged into the environment

    Energy Technology Data Exchange (ETDEWEB)

    Thereska, J.; Cuci, T.; Spahiu, P.; Plasari, E. [Institute of Nuclear Physics, Tirane (Albania). Tracer Section

    1993-12-31

    In Elbasan steel plant a large quantity of dust is discharged into the environment by laterite fluidized bed calciner and the coal boiler for steam production. By means of radiotracers the erosion of the laterite in the fluidized bed calciner was estimated experimentally. Based on the experimental data a mathematical model has been constructed for the erosion, which permits calculation of the mass of the dust deriving from erosion when the granulometric composition of the mineral on entry to the calciner is known. The efficiency of two types of cyclones in laterite calciner and coal boiler, for three granulometric classes of laterite dust and coal-ash was studied. Ways of reducing the quantity of dust discharged into environment are proposed.

  19. Memory Networks in Tinnitus: A Functional Brain Image Study

    Science.gov (United States)

    Laureano, Maura Regina; Onishi, Ektor Tsuneo; Bressan, Rodrigo Affonseca; Castiglioni, Mario Luiz Vieira; Batista, Ilza Rosa; Reis, Marilia Alves; Garcia, Michele Vargas; de Andrade, Adriana Neves; de Almeida, Roberta Ribeiro; Garrido, Griselda J.; Jackowski, Andrea Parolin

    2014-01-01

    Tinnitus is characterized by the perception of sound in the absence of an external auditory stimulus. The network connectivity of auditory and non-auditory brain structures associated with emotion, memory and attention are functionally altered in debilitating tinnitus. Current studies suggest that tinnitus results from neuroplastic changes in the frontal and limbic temporal regions. The objective of this study was to use Single-Photon Emission Computed Tomography (SPECT) to evaluate changes in the cerebral blood flow in tinnitus patients with normal hearing compared with healthy controls. Methods: Twenty tinnitus patients with normal hearing and 17 healthy controls, matched for sex, age and years of education, were subjected to Single Photon Emission Computed Tomography using the radiotracer ethylenedicysteine diethyl ester, labeled with Technetium 99 m (99 mTc-ECD SPECT). The severity of tinnitus was assessed using the “Tinnitus Handicap Inventory” (THI). The images were processed and analyzed using “Statistical Parametric Mapping” (SPM8). Results: A significant increase in cerebral perfusion in the left parahippocampal gyrus (pFWE <0.05) was observed in patients with tinnitus compared with healthy controls. The average total THI score was 50.8+18.24, classified as moderate tinnitus. Conclusion: It was possible to identify significant changes in the limbic system of the brain perfusion in tinnitus patients with normal hearing, suggesting that central mechanisms, not specific to the auditory pathway, are involved in the pathophysiology of symptoms, even in the absence of clinically diagnosed peripheral changes. PMID:24516567

  20. Memory networks in tinnitus: a functional brain image study.

    Directory of Open Access Journals (Sweden)

    Maura Regina Laureano

    Full Text Available Tinnitus is characterized by the perception of sound in the absence of an external auditory stimulus. The network connectivity of auditory and non-auditory brain structures associated with emotion, memory and attention are functionally altered in debilitating tinnitus. Current studies suggest that tinnitus results from neuroplastic changes in the frontal and limbic temporal regions. The objective of this study was to use Single-Photon Emission Computed Tomography (SPECT to evaluate changes in the cerebral blood flow in tinnitus patients with normal hearing compared with healthy controls.Twenty tinnitus patients with normal hearing and 17 healthy controls, matched for sex, age and years of education, were subjected to Single Photon Emission Computed Tomography using the radiotracer ethylenedicysteine diethyl ester, labeled with Technetium 99 m (99 mTc-ECD SPECT. The severity of tinnitus was assessed using the "Tinnitus Handicap Inventory" (THI. The images were processed and analyzed using "Statistical Parametric Mapping" (SPM8.A significant increase in cerebral perfusion in the left parahippocampal gyrus (pFWE <0.05 was observed in patients with tinnitus compared with healthy controls. The average total THI score was 50.8+18.24, classified as moderate tinnitus.It was possible to identify significant changes in the limbic system of the brain perfusion in tinnitus patients with normal hearing, suggesting that central mechanisms, not specific to the auditory pathway, are involved in the pathophysiology of symptoms, even in the absence of clinically diagnosed peripheral changes.

  1. The function genomics study

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Genomics is a biology term appeared ten years ago, used to describe the researches of genomic mapping, sequencing, and structure analysis, etc. Genomics, the first journal for publishing papers on genomics research was born in 1986. In the past decade, the concept of genomics has been widely accepted by scientists who are engaging in biology research. Meanwhile, the research scope of genomics has been extended continuously, from simple gene mapping and sequencing to function genomics study. To reflect the change, genomics is divided into two parts now, the structure genomics and the function genomics.

  2. Imaging Atherosclerotic Plaque Inflammation via Folate Receptor Targeting Using a Novel 18F-Folate Radiotracer

    Directory of Open Access Journals (Sweden)

    Adrienne Müller

    2014-03-01

    Full Text Available Folate receptor β (FR-β is overexpressed on activated, but not resting, macrophages involved in a variety of inflammatory and autoimmune diseases. A pivotal step in atherogenesis is the subendothelial accumulation of macrophages. In nascent lesions, they coordinate the scavenging of lipids and cellular debris to define the likelihood of plaque inflammation and eventually rupture. In this study, we determined the presence of FR-β-expressing macrophages in atherosclerotic lesions by the use of a fluorine-18-labeled folate-based radiotracer. Human endarterectomized specimens were used to measure gene expression levels of FR-β and CD68. Increased FR-β and CD68 levels were found in atherosclerotic plaques compared to normal artery walls by quantitative real-time polymerase chain reaction. Western blotting and immunohistochemistry demonstrated prominent FR-β protein levels in plaques. FR- β-positive cells colocalized with activated macrophages (CD68 in plaque tissue. Carotid sections incubated with 3′-aza-2′- [18F]fluorofolic acid displayed increased accumulation in atherosclerotic plaques through in vitro autoradiography. Specific binding of the radiotracer correlated with FR-β-expressing macrophages. These results demonstrate high FR-β expression in atherosclerotic lesions of human carotid tissue correlating with CD68-positive macrophages. Areas of high 3′-aza-2′-[18F]fluorofolic acid binding within the lesions represented FR-β-expressing macrophages. Selectively targeting FR-β-positive macrophages through folate-based radiopharmaceuticals may be useful for noninvasive imaging of plaque inflammation.

  3. Amyloid PET imaging in Alzheimer's disease: a comparison of three radiotracers

    Energy Technology Data Exchange (ETDEWEB)

    Landau, S.M.; Jagust, W.J. [University of California, Berkeley, Helen Wills Neuroscience Institute, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Life Sciences Division, Berkeley, CA (United States); Thomas, B.A. [University College London, Institute of Nuclear Medicine, London (United Kingdom); Thurfjell, L. [GE Healthcare, Uppsala (Sweden); Schmidt, M. [Janssen Pharmaceutica, NV, Beerse (Belgium); Margolin, R. [Janssen Alzheimer Immunotherapy, South San Francisco, CA (United States); Mintun, M.; Pontecorvo, M. [Avid Radiopharmaceuticals, Inc., Philadelphia, PA (United States); Baker, S.L. [Lawrence Berkeley National Laboratory, Life Sciences Division, Berkeley, CA (United States); Collaboration: The Alzheimer' s Disease Neuroimaging Initiative

    2014-07-15

    The increasing use of amyloid PET in Alzheimer's disease research and clinical trials has motivated efforts to standardize methodology. We compared retention of the {sup 11}C radiotracer Pittsburgh Compound B (PiB) and that of two {sup 18}F amyloid radiotracers (florbetapir and flutemetamol) using two study populations. We also examined the feasibility of converting between tracer-specific measures, using PiB as the common link between the two {sup 18}F tracers. One group of 40 subjects underwent PiB and flutemetamol imaging sessions and a separate group of 32 subjects underwent PiB and florbetapir imaging sessions. We compared cortical and white matter retention for each {sup 18}F tracer relative to that of PiB, as well as retention in several reference regions and image analysis methods. Correlations between tracer pairs were used to convert tracer-specific threshold values for amyloid positivity between tracers. Cortical retention for each pair of tracers was strongly correlated regardless of reference region (PiB-flutemetamol, ρ = 0.84-0.99; PiB-florbetapir, ρ = 0.83-0.97) and analysis method (ρ = 0.90-0.99). Compared to PiB, flutemetamol had higher white matter retention, while florbetapir had lower cortical retention. Two previously established independent thresholds for amyloid positivity were highly consistent when values were converted between tracer pairs. Despite differing white and grey matter retention characteristics, cortical retention for each {sup 18}F tracer was highly correlated with that of PiB, enabling conversion of thresholds across tracer measurement scales with a high level of internal consistency. Standardization of analysis methods and measurement scales may facilitate the comparison of amyloid PET data obtained using different tracers. (orig.)

  4. [{sup 11}C]CURB: Evaluation of a novel radiotracer for imaging fatty acid amide hydrolase by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Alan A., E-mail: alan.wilson@camhpet.c [PET Centre, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada); Human Neurochemical Pathology Laboratory, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada); Garcia, Armando; Parkes, Jun [PET Centre, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada); Houle, Sylvain [PET Centre, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada); Human Neurochemical Pathology Laboratory, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada); Tong, Junchao [Department of Psychiatry, University of Toronto, Toronto, Ontario, M5T 1R8 (Canada); Vasdev, Neil [PET Centre, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada); Human Neurochemical Pathology Laboratory, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada)

    2011-02-15

    Introduction: Fatty acid amide hydrolase (FAAH) is the enzyme responsible for metabolising the endogenous cannabinoid, anandamide, and thus represents an important target for molecular imaging. To date, no radiotracer has been shown to be useful for imaging of FAAH using either positron emission tomography (PET) or single photon emission computed tomography (SPECT). We here determine the suitability of a novel carbon-11-labeled inhibitor of FAAH via ex vivo biodistribution studies in rat brain in conjunction with pharmacological challenges. Methods: A potent irreversible inhibitor of FAAH, URB694, radiolabeled with carbon-11 in the carbonyl position ([{sup 11}C]CURB), was administered to male rats via tail-vein injection. Rats were sacrificed at various time points postinjection, and tissue samples were dissected, counted and weighed. Specific binding to FAAH was investigated by pretreatment of animals with URB694 or URB597. For metabolism and mechanism of binding studies, whole brains were excised post-radiotracer injection, homogenised and extracted exhaustively with 80% aq. acetonitrile to determine the time course and fraction of radioactivity that was irreversibly bound to brain parenchyma. Results: Upon intravenous injection into rats, [{sup 11}C]CURB showed high brain uptake [standard uptake value (SUV) of 1.6-2.4 at 5 min] with little washout over time, which is characteristic of irreversible binding. Highest uptake of radioactivity was seen in the cortex, intermediate in the cerebellum and lowest in the hypothalamus, reflecting the reported distribution of FAAH. Brain uptake of radioactivity was decreased in a dose-dependent manner by pretreatment with increasing amounts of URB694, demonstrating that binding was saturable. Pretreatment with the well-characterised FAAH inhibitor, URB597, reduced binding in all brain regions by 70-80%. Homogenised brain extraction experiments demonstrated unequivocally that [{sup 11}C]CURB was irreversibly bound to FAAH

  5. The host plant Pinus pinaster exerts specific effects on phosphate efflux and polyphosphate metabolism of the ectomycorrhizal fungus Hebeloma cylindrosporum: a radiotracer, cytological staining and (31) P NMR spectroscopy study.

    Science.gov (United States)

    Torres-Aquino, Margarita; Becquer, Adeline; Le Guernevé, Christine; Louche, Julien; Amenc, Laurie K; Staunton, Siobhan; Quiquampoix, Hervé; Plassard, Claude

    2017-02-01

    Ectomycorrhizal (ECM) association can improve plant phosphorus (P) nutrition. Polyphosphates (polyP) synthesized in distant fungal cells after P uptake may contribute to P supply from the fungus to the host plant if they are hydrolyzed to phosphate in ECM roots then transferred to the host plant when required. In this study, we addressed this hypothesis for the ECM fungus Hebeloma cylindrosporum grown in vitro and incubated without plant or with host (Pinus pinaster) and non-host (Zea mays) plants, using an experimental system simulating the symbiotic interface. We used (32) P labelling to quantify P accumulation and P efflux and in vivo and in vitro nuclear magnetic resonance (NMR) spectroscopy and cytological staining to follow the fate of fungal polyP. Phosphate supply triggered a massive P accumulation as newly synthesized long-chain polyP in H. cylindrosporum if previously grown under P-deficient conditions. P efflux from H. cylindrosporum towards the roots was stimulated by both host and non-host plants. However, the host plant enhanced (32) P release compared with the non-host plant and specifically increased the proportion of short-chain polyP in the interacting mycelia. These results support the existence of specific host plant effects on fungal P metabolism able to provide P in the apoplast of ectomycorrhizal roots.

  6. Improving phosphorus availability from Patos phosphate rock for Eucalyptus: a study with 32P radiotracer; Melhorando a disponibilidade de fosforo da rocha fosforica de Patos para eucalipto: um estudo com radiotracador 32P

    Energy Technology Data Exchange (ETDEWEB)

    Villanueva, Felipe Carlos Alvarez [Instituto de Investigaciones Fundamentales en Agriculturea Tropical (INIFAT), Santiago de las Vegas, La Habana (Cuba)]. E-mail: falvarez@cena.usp.br; Muraoka, Takashi; Trevizam, Anderson Ricardo [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de Fertilidade do Solo; Franzini, Vinicius Ide [Sao Paulo Univ., Piracicaba, SP (Brazil). Escola Superior de Agricultura Luiz de Queiroz. Programa de Pos-graduacao em Solos e Nutricao de Plantas; Rocha, Alexandre Prado [Escola de Engenharia de Piracicaba, SP (Brazil)

    2006-01-15

    Eucalyptus plantation in Brazil is generally set on low fertility soils, therefore phosphorus (P) fertilization is mandatory and increases the cost of plantation operation. Using species that more efficiently uptake phosphorus from less soluble sources is an interesting option. However, little is known about eucalyptus regarding its ability of using less soluble forms of phosphorus. The use of P by eucalyptus (E. urophylla, E. grandis, and E. urophylla E. grandis) was studied in greenhouse using a loamy-textured, hipodystrophic Typic Haplustox from the Cerrado region, and 32P isotopic method. The P sources tested were triple superphosphate (TSP), phosphate rock (PR) and the triple superphosphate mixed with PR (TSP+PR). The effectiveness of P sources in terms of increasing dry matter yield was TSP = (TSP + PR) > PR, and the P uptake followed the order (TSP + PR) > TSP > PR for both species plus the hybrid. The increase in P uptake from PR due to TSP influence was 217.3% for E. urophylla, 235.7% for E. grandis, and 28.7% for E. urophylla E. grandis, indicating an enhancement effect of TSP on the effectiveness of PR. The hybrid E. urophylla E. grandis was the most efficient genotype on P soil use and E. grandis most exigent in P fertilizer. (author)

  7. Radiotracer Methods for Targeted Imaging of the Epidermal Growth Factor Receptor

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Kyung Ho; Lee, Kyung Han [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2008-06-15

    While indirect targeting strategies using reporter-genes are taking center stage in current molecular imaging research, another vital strategy has long involved direct imaging of specific receptors using radiolabeled ligands. Recently, there is renewal of immense interest in this area with particular attention to the epidermal growth factor receptor (EGFR), a transmembrane glycoprotein critically involved in the regulation of many cellular functions and malignancies. Recently, two novel classes of EGFR-targeting anticancer drugs have entered clinical trials with great expectations. These are monoclonal antibodies such as cetuximab that target the extracellular domain, and small molecule tyrosine kinase inhibitors such as gefitinib (Iressa) and erlotinib (Tarceva) that target the catalytic domain of the receptor. However, early results have showed disappointing survival benefits, disclosing a major challenge for this therapeutic strategy; namely, the need to identify tumors that are most likely to respond to the agents. To address this important clinical issue, several noninvasive imaging techniques are under investigation including radiolabeled probes based on small molecule tyrosine kinase inhibitors, anti-EGFR antibodies, and EGF peptides. This review describes the current status, limitations, and future prospects in the development of radiotracer methods for EGFR imaging.

  8. Development of Tyrosine-Based Radiotracer Tc99m-N4-Tyrosine for Breast Cancer Imaging

    Directory of Open Access Journals (Sweden)

    Fan-Lin Kong

    2012-01-01

    Full Text Available The purpose of this study was to develop an efficient way to synthesize Tc99m-O-[3-(1,4,8,11-tetraazabicyclohexadecane-propyl]-tyrosine (Tc99m-N4-Tyrosine, a novel amino acid-based radiotracer, and evaluate its potential in breast cancer gamma imaging. Precursor N4-Tyrosine was synthesized using a 5-step procedure, and its total synthesis yield was 38%. It was successfully labeled with Tc99m with high radiochemical purity (>95%. Cellular uptake of Tc99m-N4-Tyrosine was much higher than that of Tc99m-N4 and the clinical gold standard 18F-2-deoxy-2-fluoro-glucose (18F-FDG in rat breast tumor cells in vitro. Tissue uptake and dosimetry estimation in normal rats revealed that Tc99m-N4-Tyrosine could be safely administered to humans. Evaluation in breast tumor-bearing rats showed that although Tc99m-N4-Tyrosine appeared to be inferior to 18F-FDG in distinguishing breast tumor tissue from chemical-induced inflammatory tissue, it had high tumor-to-muscle uptake ratios and could detect breast tumors clearly by planar scintigraphic imaging. Tc99m-N4-Tyrosine could thus be a useful radiotracer for use in breast tumor diagnostic imaging.

  9. Novel (99m)Tc(III) Complexes [(99m)TcCl(CDO)(CDOH)2B-R] (CDOH2 = Cyclohexanedione Dioxime) Useful as Radiotracers for Heart Imaging.

    Science.gov (United States)

    Liu, Min; Fang, Wei; Liu, Shuang

    2016-11-16

    In this study, we evaluated seven new (99m)Tc(III) complexes [(99m)TcCl(CDO)(CDOH)2B-R] ((99m)Tc-2Fboroxime: R = 2-formylfuran-3-yl (2F); (99m)Tc-3Fboroxime: R = furan-3-yl (3F); (99m)Tc-5Fboroxime: R = 5-formyfuran-2-yl (5F); (99m)Tc-HPboroxime: R = 6-hydroxylpyridin-2-yl (HP); (99m)Tc-MPYboroxime: R = 5-methoxypyridin-3-yl (MPY); (99m)Tc-PMboroxime: R = 1,5-pyrimidin-3-yl (PM); and (99m)Tc-4PYboroxime: R = pyridin-4-yl (4PY)) for their potential as heart imaging agents. All new (99m)Tc(III) radiotracers except (99m)Tc-2Fboroxime were prepared with high radiochemical purity (RCP > 95%). The low RCP (∼75%) for (99m)Tc-2Fboroxime is most likely caused by steric hindrance from the 3-formyl group. Biodistribution and imaging studies were performed in SD rats. Planar image quantification was performed to compare their myocardial retention times. We found that the myocardial washout curves of new (99m)Tc(III) radiotracers were best fitted the biexponential decay function. The AUC (area under the curve) values followed the general trend: (99m)Tc-5Fboroxime (129 ± 6) > (99m)Tc-3Fboroxime (114 ± 11) > (99m)Tc-Teboroxime (104 ± 16) > (99m)Tc-MPYboroxime (92 ± 18) > (99m)Tc-4PYboroxime (77 ± 10) > (99m)Tc-PMboroxime (68 ± 14) ≈ (99m)Tc-HPboroxime (62 ± 14). The 2 min heart uptake values from biodistribution studies follow the ranking order of (99m)Tc-5Fboroxime (3.75 ± 0.15%ID/g) ≈ (99m)Tc-MPYboroxime (3.73 ± 0.24%ID/g) > (99m)Tc-PMboroxime (3.47 ± 0.15%ID/g) ≈ (99m)Tc-3Fboroxime ≈ (3.25 ± 0.77%ID/g). The 5 min heart uptake of (99m)Tc-5Fboroxime (3.91 ± 0.09%ID/g) was almost identical to its 2 min heart uptake (3.75 ± 0.15%ID/g), and its 15 min heart uptake value (2.83 ± 0.08%ID/g) compared well to the 2 min heart uptake of (99m)Tc-Teboroxime (3.00 ± 0.37%ID/g). It took ∼5 min for (99m)Tc-5Fboroxime to approach the 1 min heart uptake value of (99m)Tc-Teboroxime (∼3.5% ID/g) and ∼9.5 min to reach the 2 min heart uptake value of (99m

  10. Development of a fluidized-bed method for on-line evaluation of radiotracers in vitro; Entwicklung einer Fliessbettechnik zur Bewertung von Radiopharmaka an Zellkulturen

    Energy Technology Data Exchange (ETDEWEB)

    Noll, T.

    1999-05-01

    This study presents the development of a continuously operating fluidized-bed bioreactor for on-line evaluation of radiotracers in vitro, which combines tissue-like three-dimensional cell cultivation in open porous microcarriers with a technique for on-line radioactivity detection. The long time stability of steady-state permits a large number of experiments using the same culture. All relevant parameters (O{sub 2}, pH, T, etc.) can be adjusted according to the experimental requirements. The flux of the circulating medium can be adapted to the blood flow of the corresponding organism, while the input function of the radiotracer is freely adjustable for simulation of in vivo conditions. Sampling and examination of the immobilized cells care possible at any time. Using this system, the kinetics of 2-[{sup 18}F]fluoro-2-deoxyglucose (FDG) in human glioma cells (86HG39) were studied and it was shown that the dependence of the lumped constant (LC) for FDG on the medium glucose concentration is similar to that obtained in the rat brain. For normoglycemic concentrations the LC was determined to be in the range of 0.7, while in hypoglycemia it increased progressively up to a value of 1.22 at a glucose concentration of 3 mM. The rate constants in the three compartment model were found to be similar to those obtained in vivo using PET; indicating the validity of the system for tracer evaluation. Furthermore the kinetics of both diastereomeric forms of 4-[{sup 18}F]fluoro-proline was investigated and found that both diastereomeres were not metabolized and reached an identical intracellular steady state concentration. The trans-form was transported three times faster than the cis-diastereomere, indicated by the rate constants. (orig.) [German] Diese Arbeit beschreibt die Entwicklung eines kontinuierlich betriebenen Wirbelschichtreaktors zur on-line Bewertung von Radiotracern an Zellkulturen. Der Bioreaktor kombiniert eine gewebeaehnliche, dreidimensionale Zellkultivierung in

  11. Synthesis and characterization of (68)Ga-labeled curcumin and curcuminoid complexes as potential radiotracers for imaging of cancer and Alzheimer's disease.

    Science.gov (United States)

    Asti, Mattia; Ferrari, Erika; Croci, Stefania; Atti, Giulia; Rubagotti, Sara; Iori, Michele; Capponi, Pier C; Zerbini, Alessandro; Saladini, Monica; Versari, Annibale

    2014-05-19

    Curcumin (CUR) and curcuminoids complexes labeled with fluorine-18 or technetium-99m have recently shown their potential as diagnostic tools for Alzheimer's disease. Gallium-68 is a positron-emitting, generator-produced radionuclide, and its properties can be exploited in situ in medical facilities without a cyclotron. Moreover, CUR showed a higher uptake in tumor cells compared to normal cells, suggesting potential diagnostic applications in this field. In spite of this, no studies using labeled CUR have been performed in this direction, so far. Herein, (68)Ga-labeled complexes with CUR and two curcuminoids, namely diacetyl-curcumin (DAC) and bis(dehydroxy)curcumin (bDHC), were synthesized and characterized by means of experimental and theoretical approaches. Moreover, a first evaluation of their affinity to synthetic β-amyloid fibrils and uptake by A549 lung cancer cells was performed to show the potential application of these new labeled curcuminoids in these diagnostic fields. The radiotracers were prepared by reacting (68)Ga(3+) obtained from a (68)Ge/(68)Ga generator with 1 mg/mL curcuminoids solutions. Reaction parameters (precursor amount, reaction temperature, and pH) were optimized to obtain high and reproducible radiochemical yield and purity. Stoichiometry and formation of the curcuminoid complexes were investigated by matrix-assisted laser desorption ionization time-of-flight mass spectrometry, NMR, ultraviolet-visible, and fluorescence spectroscopy on the equivalent (nat)Ga-curcuminoids (nat = natural) complexes, and their structure was computed by theoretical density functional theory calculations. The analyses evidenced that CUR, DAC, and bDHC were predominantly in the keto-enol form and attested to Ga(L)2(+) species formation. Identity of the (68)Ga(L)2(+) complexes was confirmed by coelution with the equivalent (nat)Ga(L)2(+) complexes in ultrahigh-performance liquid chromatography analyses.(68)Ga(CUR)2(+), (68)Ga(DAC)2(+), and (68)Ga(bDHC)2

  12. Development of a system for real-time measurements of metabolite transport in plants using short-lived positron-emitting radiotracers

    Science.gov (United States)

    Kiser, Matthew R.

    be introduced to plants as biologically active molecules such as 11CO2, N13O-3, 18F--[H2O], and H152O . Plants for these studies are grown in controlled-environment chambers at the Phytotron. The chambers offer an array of control for temperature, humidity, atmospheric CO2 concentration, and light intensity. Additionally, the Phytotron houses one large reach-in growth chamber that is dedicated to this project for radioisotope labeling measurements. There are several important properties of short-lived positron-emitting radio-tracers that make them well suited for use in investigating metabolite transport in plants. First, because the molecular mass of a radioisotope-tagged compound is only minutely different from the corresponding stable compound, radiotracer substances should be metabolized and transported in plants the same as their non-radioactive counterparts. Second, because the relatively high energy gamma rays emitted from electron-positron annihilation are attenuated very little by plant tissue, the real-time distribution of a radiotracer can be measured in vivo in plants. Finally, the short radioactive half-lives of these isotopes allow for repeat measurements on the same plant in a short period of time. For example, in studies of short-term environmental changes on plant metabolite dynamics, a single plant can be labeled multiple times to measure its responses to different, environmental conditions. Also, different short-lived radiotracers can be applied to the same plant over a short period of time to investigate the transport and allocation of various metabolites. This newly developed system provides the capabilities for production of 11CO2 at TUNL, transfer of the 11CO 2 gas from the target area at TUNL to a radiation-shielded cryogenic trap at the Phytotron, labeling of photoassimilates with 11C, and in vivo gamma-ray detection for real-time measurements of the radiotracer distribution in small plants. The experimental techniques and instrumentation

  13. Investigating phosphorus uptake in anoxic and sulfidic surface sediments with 33P radiotracer experiments

    Science.gov (United States)

    Dijkstra, Nikki; Kraal, Peter; Gonzalez, Santiago; Slomp, Caroline

    2016-04-01

    Phosphorus (P) is a key nutrient for marine organisms. Enhanced P availability in the water column can fuel algal blooms and the development of bottom water anoxia. Recently, it was suggested that micro-organisms in sediments overlain by anoxic and sulfidic bottom waters might take up dissolved P and form Fe(II)-P minerals, thereby enhancing P removal. In this study, we investigated the uptake of P in surface sediments with 33P radiotracer experiments. The sediments were recovered from the anoxic and sulfidic deep basin of the Black Sea and, for comparison, from the adjacent oxic shelf. Results suggest a very fast sedimentary uptake of 33P at all sites but in particular for sediments from the oxic shelf. At all sites, most 33P was sequestered in the citrate-dithionite-bicarbonate-(CDB)-extractable sediment P fraction. No significant differences with abiotic controls were observed, implying that micro-organisms were not directly involved in the P uptake. Whereas 33P uptake by the oxic shelf sediment was likely controlled by sorption of 33P to iron(Fe)-(oxyhydr)oxides, the nature of the CDB-extractable P fraction in the deep basin sediments remains unclear. We discuss whether authigenic formation of Fe(II)-P minerals or fast adsorption of P to calcites may explain our findings.

  14. Determination of oil reservoir radiotracer (S{sup 14}CN{sup -}) in a single step using a plastic scintillator extractive resin

    Energy Technology Data Exchange (ETDEWEB)

    Bagan, H.; Tarancon, A. [Departament de Quimica Analitica, Universitat de Barcelona, Diagonal 645, E-08028 Barcelona (Spain); Stavsetra, L. [Department for Reservoir and Exploration Technology, Institute for Energy Technology (IFE), Instituttveien 18, N-2027 Kjeller (Norway); Rauret, G. [Departament de Quimica Analitica, Universitat de Barcelona, Diagonal 645, E-08028 Barcelona (Spain); Garcia, J.F., E-mail: jfgarcia@ub.edu [Departament de Quimica Analitica, Universitat de Barcelona, Diagonal 645, E-08028 Barcelona (Spain)

    2012-07-29

    Highlights: Black-Right-Pointing-Pointer A new procedure for S{sup 14}CN{sup -} radiotracer determination using PS resin was established. Black-Right-Pointing-Pointer The minimum detectable activity for a 100 mL sample is 0.08 Bq L{sup -1}. Black-Right-Pointing-Pointer The minimum quantifiable activity for a 100 mL sample is 0.31 Bq L{sup -1}. Black-Right-Pointing-Pointer PS resin is capable to quantify S{sup 14}CN{sup -} radiotracer samples with errors lower than 5%. Black-Right-Pointing-Pointer PS resin is also capable to quantify complex matrices obtained from oil reservoirs. - Abstract: The analysis of radiotracers is important in the study of oil reservoir dynamics. One of the most widely used radiotracer is S{sup 14}CN{sup -}. Prior to activity measurements by Liquid Scintillation (LS), routine determinations require the pretreatment steps of purification and concentration of the samples using anion exchange columns. The final elution media produces samples with high salt concentration that may lead to problems with phase separation during the LS measurement. Plastic Scintillation (PS) is an alternative technique that provides a solid surface that can be used as a platform for the immobilisation of selective extractants to obtain a PS resin. The proposed procedure unifies chemical separation and sample measurement preparation in a single step, serving to reduce the number of reagents needed and manpower required for the analysis while also avoiding mixed waste production by LS. The objective of this study is to develop a PS resin for the determination of {sup 14}C-labelled thiocyanate radiotracer in water samples. For this purpose, the immobilisation procedure was optimised, including optimisation of the proportion of PS microspheres:extractant and the use of a control blank to monitor the PS resin immobilisation process. The breakthrough volume was studied and the detection and quantification limits for 100 mL of sample were determined to be 0.08 Bq L{sup -1

  15. Brain SPECT imaging and whole-body biodistribution with [{sup 123}I]ADAM - a serotonin transporter radiotracer in healthy human subjects

    Energy Technology Data Exchange (ETDEWEB)

    Lin, K.-J. [Graduate Institute of Clinical Medical Sciences, Chang-Gung University, Tao-Yuan 333, Taiwan (China); Molecular Imaging Center, Chang-Gung Memorial Hospital, Tao-Yuan 333, Taiwan (China); Department of Nuclear Medicine, Chang-Gung Memorial Hospital, Tao-Yuan 333, Taiwan (China); Liu, C.-Y. [Neuroscience Research Center, Chang-Gung Memorial Hospital, Tao-Yuan 333, Taiwan (China); Department of Psychiatry, Chang-Gung Memorial Hospital, Tao-Yuan 333, Taiwan (China); Wey, S.-P. [Molecular Imaging Center, Chang-Gung Memorial Hospital, Tao-Yuan 333, Taiwan (China); Department of Medical Imaging and Radiological Sciences, Chang-Gung University, Tao-Yuan 333, Taiwan (China); Hsiao, I.-T. [Molecular Imaging Center, Chang-Gung Memorial Hospital, Tao-Yuan 333, Taiwan (China); Department of Medical Imaging and Radiological Sciences, Chang-Gung University, Tao-Yuan 333, Taiwan (China); Wu, Jay [Health Physics Divisions, Atomic Energy Council, Institute of Nuclear Energy Research, Tao-Yuan 325, Taiwan (China); Fu, Y.-K. [Atomic Energy Council, Institute of Nuclear Energy Research, Tao-Yuan 325, Taiwan (China); Yen, T.-C. [Molecular Imaging Center, Chang-Gung Memorial Hospital, Tao-Yuan 333, Taiwan (China) and Department of Nuclear Medicine, Chang-Gung Memorial Hospital, Tao-Yuan 333, Taiwan (China)]. E-mail: yen1110@adm.cgmh.org.tw

    2006-02-15

    Introduction: [{sup 123}I]-2-((2-((dimethylamino)methyl)phenyl)thio)-5-iodophenylamine ([{sup 123}I]ADAM), a novel radiotracer, has promising application in the imaging of the serotonin transporter (SERT) in the human brain. In this study, the optimal scanning time for acquiring brain single photon emission computed tomography (SPECT) images was determined by performing dynamic SPECT studies at intervals from 0 to 6 h postinjection of [{sup 123}I]ADAM. Additionally, radiation-absorbed doses were determined for three healthy human subjects using attenuation-corrected images. Methods: Twelve subjects were randomized into one of three study groups as follows: whole-body distribution imaging (n=3), dynamic SPECT imaging (n=3) and brain SPECT imaging (n=6). The radiation-absorbed dose was calculated using MIRDOSE 3.0 software with attenuation-corrected data. The specific binding (SB) ratio of the brain stem was measured from dynamic SPECT images to determine the optimal scanning time. Results: Dynamic SPECT images showed that the SB of the brain stem gradually increased to a maximum 4 h postinjection. Single photon emission computed tomography images at 4 h postinjection showed a high uptake of the radiotracer (SB) in the hypothalamus (1.40{+-}0.12), brain stem (1.44{+-}0.16), pons (1.13{+-}0.14) and medial temporal lobe (0.59{+-}0.10). The mean adult male value of effective dose was 3.37x10{sup -2} mSv/MBq with a 4.8-h urine-voiding interval. Initial high uptake in SERT-rich sites was demonstrated in the lung and brain. A prominent washout of the radiotracer from the lung further increased brain radioactivity that reached a peak value of 5.03% of injected dose 40 min postinjection. Conclusions: [{sup 123}I]ADAM is a promising radiotracer for SPECT imaging of SERT in humans with acceptable dosimetry and high uptake in SERT-rich regions. Brain SPECT images taken within 4 h following injection show optimal levels of radiotracer uptake in known SERT sites. However, dynamic

  16. Evaluation of bone-seeking novel radiotracer {sup 68}Ga-NO2AP-Bisphosphonate for the detection of skeletal metastases in carcinoma breast

    Energy Technology Data Exchange (ETDEWEB)

    Passah, Averilicia; Tripathi, Madhavi; Ballal, Sanjana; Yadav, Madhav Prasad; Kumar, Rajeev; Chakraborty, Partha Sarathi; Bal, Chandrasekhar [All India Institute of Medical Sciences, Department of Nuclear Medicine, Ansari Nagar, New Delhi (India); Roesch, Frank; Meckel, Marian [Johannes-Gutenberg-University, Nuclear Chemistry, Mainz (Germany)

    2017-01-15

    The successful labelling of bisphosphonates (BP) with {sup 68}Ga using macrocyclic chelators such as the based triazacyclononane (NO2AP) is a step forward in the in-house availability of a novel bone-seeking PET radiopharmaceutical with dual advantage of PET/CT imaging and generator production. In this study, we compared the novel generator-based skeletal radiotracer {sup 68}Ga-1,4,7-triazacyclonone-1,4-diacetic acid ({sup 68}Ga-NO2AP-BP) with sodium fluoride ({sup 18}F-NaF) for the detection of skeletal metastases in breast cancer patients. In addition, dosimetric analysis of {sup 68}Ga-NO2AP-BP was performed in a subset of patients. This was a prospective study of histopathologically proven cases of breast cancer patients who were referred for bone scintigraphy and underwent positron emission tomography/computed tomography (PET/CT) with {sup 18}F-NaF and {sup 68}Ga-NO2AP-BP within a week in random order. The scans of each patient were compared both qualitatively for image quality and quantitatively for number of lesions and SUVmax of lesions. Dosimetric analysis was performed in five patients. Their PET/CT scans were acquired at multiple time points and urine and blood samples were collected. Dosimetric calculations were performed using OLINDA/EXM 1.1 software. Statistical analysis was done using Stata 13 (StataCorp) software package. An agreement analysis regarding number of lesions detected with the two skeletal radiotracers was carried out. The image quality of {sup 68}Ga-NO2AP-BP PET/CT scans were comparable to that of {sup 18}F-NaF. There was no statistically significant difference in the SUVmax of lesions, normal bone and lesion to background ratio between the two skeletal radiotracers. There was good agreement in the number of lesions detected by both skeletal radiotracers. The mean whole body effective dose for {sup 68}Ga-NO2AP-BP was 0.00583 mSv/MBq and the effective dose equivalent was 0.0086 mSv/MBq. The excellent lesion detection agreement between

  17. Evaluation of bone-seeking novel radiotracer (68)Ga-NO2AP-Bisphosphonate for the detection of skeletal metastases in carcinoma breast.

    Science.gov (United States)

    Passah, Averilicia; Tripathi, Madhavi; Ballal, Sanjana; Yadav, Madhav Prasad; Kumar, Rajeev; Roesch, Frank; Meckel, Marian; Sarathi Chakraborty, Partha; Bal, Chandrasekhar

    2017-01-01

    The successful labelling of bisphosphonates (BP) with (68)Ga using macrocyclic chelators such as the based triazacyclononane (NO2AP) is a step forward in the in-house availability of a novel bone-seeking PET radiopharmaceutical with dual advantage of PET/CT imaging and generator production. In this study, we compared the novel generator-based skeletal radiotracer (68)Ga-1,4,7-triazacyclonone-1,4-diacetic acid ((68)Ga-NO2AP-BP) with sodium fluoride ((18)F-NaF) for the detection of skeletal metastases in breast cancer patients. In addition, dosimetric analysis of (68)Ga-NO2AP-BP was performed in a subset of patients. This was a prospective study of histopathologically proven cases of breast cancer patients who were referred for bone scintigraphy and underwent positron emission tomography/computed tomography (PET/CT) with (18)F-NaF and (68)Ga-NO2AP-BP within a week in random order. The scans of each patient were compared both qualitatively for image quality and quantitatively for number of lesions and SUVmax of lesions. Dosimetric analysis was performed in five patients. Their PET/CT scans were acquired at multiple time points and urine and blood samples were collected. Dosimetric calculations were performed using OLINDA/EXM 1.1 software. Statistical analysis was done using Stata 13 (StataCorp) software package. An agreement analysis regarding number of lesions detected with the two skeletal radiotracers was carried out. The image quality of (68)Ga-NO2AP-BP PET/CT scans were comparable to that of (18)F-NaF. There was no statistically significant difference in the SUVmax of lesions, normal bone and lesion to background ratio between the two skeletal radiotracers. There was good agreement in the number of lesions detected by both skeletal radiotracers. The mean whole body effective dose for (68)Ga-NO2AP-BP was 0.00583 mSv/MBq and the effective dose equivalent was 0.0086 mSv/MBq. The excellent lesion detection agreement between (68)Ga-NO2AP-BP and (18)F-NaF favours the

  18. Development of new folate-based PET radiotracers: preclinical evaluation of {sup 68}Ga-DOTA-folate conjugates

    Energy Technology Data Exchange (ETDEWEB)

    Fani, Melpomeni; Maecke, Helmut R. [University Hospital Basel, Division of Radiological Chemistry, Basel (Switzerland); University Hospital Freiburg, Clinic for Nuclear Medicine, Freiburg (Germany); Wang, Xuejuan [University Hospital Basel, Division of Radiological Chemistry, Basel (Switzerland); Nicolas, Guillaume [University Hospital Basel, Department of Nuclear Medicine, Basel (Switzerland); Medina, Christelle; Raynal, Isabelle; Port, Marc [Guerbet, Research Department, Aulnay-sous-Bois (France)

    2011-01-15

    A number of {sup 111}In- and {sup 99m}Tc-folate-based tracers have been evaluated as diagnostic agents for imaging folate receptor (FR)-positive tumours. A {sup 68}Ga-folate-based radiopharmaceutical would be of great interest, combining the advantages of PET technology and the availability of {sup 68}Ga from a generator. The aim of the study was to develop a new {sup 68}Ga-folate-based PET radiotracer. Two new DOTA-folate conjugates, named P3026 and P1254, were synthesized using the 1,2-diaminoethane and 3-{l_brace}2-[2-(3-amino-propoxy)-ethoxy]-ethoxy{r_brace}-propylamine as a spacer, respectively. Both conjugates were labelled with {sup 67/68}Ga. Binding affinity, internalization and externalization studies were performed using the FR-positive KB cell line. Biodistribution and PET/CT imaging studies were performed in nude mice, on a folate-deficient diet, bearing KB and HT1080 (FR-negative) tumours, concurrently. The new radiotracers were evaluated comparatively to the reference molecule {sup 111}In-DTPA-folate ({sup 111}In-P3139). The K{sub d} values of {sup 67/68}Ga-P3026 (4.65 {+-} 0.82 nM) and {sup 67/68}Ga-P1254 (4.27 {+-} 0.42 nM) showed high affinity for the FR. The internalization rate followed the order {sup 67/68}Ga-P3026 >{sup 67/68}Ga-P1254 >{sup 111}In-P3139, while almost double cellular retention was found for {sup 67/68}Ga-P3026 and {sup 67/68}Ga-P1254, compared to {sup 111}In-P3139. The biodistribution data of {sup 67/68}Ga-DOTA-folates showed high and receptor-mediated uptake on the FR-positive tumours and kidneys, with no significant differences compared to {sup 111}In-P3139. PET/CT images, performed with {sup 68}Ga-P3026, showed high uptake in the kidneys and clear visualization of the FR-positive tumours. The DOTA-folate conjugates can be efficiently labelled with {sup 68}Ga in labelling yields and specific activities which allow clinical application. The characteristics of the {sup 67/68}Ga-DOTA-folates are comparable to {sup 111}In

  19. Use of supercritical carbon dioxide fluid as a solvent for the purification of pet radiotracers

    Energy Technology Data Exchange (ETDEWEB)

    Ferrieri, R.A.; Fowler, J.S.; Wolf, A.P.

    1993-12-31

    We have identified superfluid chromatography (SFC) as a promising method which could offer advantages in radiotracer purification through rapid separation, as well as, improved recovery and purity of labeled product. Using SF CO{sub 2} as the mobile phase for chromatographic separation of labeled product would eliminate the need for solvent removal from product prior to delivery.

  20. Increasing the accuracy of radiotracer monitoring in one-dimensional flow using polynomial deconvolution correction.

    Science.gov (United States)

    Gholipour Peyvandi, Reza; Taheri, Ali

    2016-01-01

    Factors such as type of fluid movement and gamma-ray scattering may decrease the precision of the radiotracer monitoring as the response to a short tracer injection. Practical experiences using polynomial deconvolution techniques are presented. These techniques were successfully applied for correcting the obtained experimental results and increasing the time resolution of the method. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. PET imaging of HSV1-tk mutants with acquired specificity toward pyrimidine- and acycloguanosine-based radiotracers

    Energy Technology Data Exchange (ETDEWEB)

    Likar, Yury; Dobrenkov, Konstantin; Olszewska, Malgorzata; Shenker, Larissa; Hricak, Hedvig; Ponomarev, Vladimir [Memorial Sloan-Kettering Cancer Center, Molecular Imaging Laboratory, Department of Radiology, New York, NY (United States); Cai, Shangde [Memorial Sloan-Kettering Cancer Center, Radiochemistry/Cyclotron Core Facility, New York, NY (United States)

    2009-08-15

    The aim of this study was to create an alternative mutant of the herpes simplex virus type 1 thymidine kinase (HSV1-tk) reporter gene with reduced phosphorylation capacity for acycloguanosine derivatives, but not pyrimidine-based compounds that will allow for successful PET imaging. A new mutant of HSV1-tk reporter gene, suitable for PET imaging using pyrimidine-based radiotracers, was developed. The HSV1-tk mutant contains an arginine-to-glutamine substitution at position 176 (HSV1-R176Qtk) of the nucleoside binding region of the enzyme. The mutant-gene product showed favorable enzymatic characteristics toward pyrimidine-based nucleosides, while exhibiting reduced activity with acycloguanosine derivatives. In order to enhance HSV1-R176Qtk reporter activity with pyrimidine-based radiotracers, we introduced the R176Q substitution into the more active HSV1-sr39tk mutant. U87 human glioma cells transduced with the HSV1-R176Qsr39tk double mutant reporter gene showed high {sup 3}H-FEAU pyrimidine nucleoside and low {sup 3}H-penciclovir acycloguanosine analog uptake in vitro. PET imaging also demonstrated high {sup 18}F-FEAU and low {sup 18}F-FHBG accumulation in HSV1-R176Qsr39tk+ xenografts. The feasibility of imaging two independent nucleoside-specific HSV1-tk mutants in the same animal with PET was demonstrated. Two opposite xenografts expressing the HSV1-R176Qsr39tk reporter gene and the previously described acycloguanosine-specific mutant of HSV1-tk, HSV1-A167Ysr39tk reporter gene, were imaged using a short-lived pyrimidine-based {sup 18}F-FEAU and an acycloguanosine-based {sup 18}F-FHBG radiotracer, respectively, administered on 2 consecutive days. We conclude that in combination with acycloguanosine-specific HSV1-A167Ysr39tk reporter gene, a HSV1-tk mutant containing the R176Q substitution could be used for PET imaging of two different cell populations or concurrent molecular biological processes in the same living subject. (orig.)

  2. Effect of cyclosporin A on the uptake of D{sub 3}-selective PET radiotracers in rat brain

    Energy Technology Data Exchange (ETDEWEB)

    Tu Zhude; Li Shihong; Xu Jinbin; Chu Wenhua; Jones, Lynne A. [Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110 (United States); Luedtke, Robert R. [Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107 (United States); Mach, Robert H., E-mail: rhmach@mir.wustl.edu [Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110 (United States); Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110 (United States); Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110 (United States)

    2011-07-15

    Introduction: Four benzamide analogs having a high affinity and selectivity for D{sub 3} versus D{sub 2} receptors were radiolabeled with {sup 11}C or {sup 18}F for in vivo evaluation. Methods: Precursors were synthesized, and the four D{sub 3} selective benzamide analogs were radiolabeled. The tissue distribution and brain uptake of the four compounds were evaluated in control rats and rats pretreated with cyclosporin A, a modulator of P-glycoprotein and an inhibitor of other ABC efflux transporters that contribute to the blood brain barrier. Micro-positron emission tomographic (PET) imaging was carried out for [{sup 11}C]6 in a control and a cyclosporin A pretreated rat. Results: All four compounds showed low brain uptake in control rats at 5 and 30 min post-injection; despite recently reported rat behavioral studies conducted on analogs 6 (WC-10) and 7 (WC-44). Following administration of cyclosporin A, increased brain uptake was observed with all four PET radiotracers at both 5 and 30 min post-intravenous injection. An increase in brain uptake following modulation/inhibition of the ABC transporters was also observed in the microPET study. Conclusions: These data suggest that D3 selective conformationally-flexible benzamide analogs which contain a N-2-methoxyphenylpiperazine moiety are substrates for P-glycoprotein or other adenosine triphosphate (ATP)-binding cassette transporters expressed at the blood-brain barrier, and that PET radiotracers containing this pharmacophore may display low brain uptake in rodents due to the action of these efflux transporters.

  3. Comparison of In Vitro Assays in Selecting Radiotracers for In Vivo P-Glycoprotein PET Imaging

    Directory of Open Access Journals (Sweden)

    Renske M. Raaphorst

    2017-09-01

    Full Text Available Positron emission tomography (PET imaging of P-glycoprotein (P-gp in the blood-brain barrier can be important in neurological diseases where P-gp is affected, such as Alzheimer´s disease. Radiotracers used in the imaging studies are present at very small, nanomolar, concentration, whereas in vitro assays where these tracers are characterized, are usually performed at micromolar concentration, causing often discrepant in vivo and in vitro data. We had in vivo rodent PET data of [11C]verapamil, (R-N-[18F]fluoroethylverapamil, (R-O-[18F]fluoroethyl-norverapamil, [18F]MC225 and [18F]MC224 and we included also two new molecules [18F]MC198 and [18F]KE64 in this study. To improve the predictive value of in vitro assays, we labeled all the tracers with tritium and performed bidirectional substrate transport assay in MDCKII-MDR1 cells at three different concentrations (0.01, 1 and 50 µM and also inhibition assay with P-gp inhibitors. As a comparison, we used non-radioactive molecules in transport assay in Caco-2 cells at a concentration of 10 µM and in calcein-AM inhibition assay in MDCKII-MDR1 cells. All the P-gp substrates were transported dose-dependently. At the highest concentration (50 µM, P-gp was saturated in a similar way as after treatment with P-gp inhibitors. Best in vivo correlation was obtained with the bidirectional transport assay at a concentration of 0.01 µM. One micromolar concentration in a transport assay or calcein-AM assay alone is not sufficient for correct in vivo prediction of substrate P-gp PET ligands.

  4. Synthesis of carbon-11, fluorine-18, and nitrogen-13 labeled radiotracers for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, J.S.; Wolf, A.P.

    1981-01-01

    A number of reviews, many of them recent, have appeared on various aspects of /sup 11/C, /sup 18/F and /sup 13/N-labeled radiotracers. This monograph treats the topic principally from the standpoint of synthetic organic chemistry while keeping in perspective the necessity of integrating the organic chemistry with the design and ultimate application of the radiotracer. Where possible, recent examples from the literature of organic synthesis are introduced to suggest potentially new routes which may be applied to problems in labeling organic molecules with the short-lived positron emitters, carbon-11, fluorine-18, and nitrogen-13. The literature survey of carbon-11, fluorine-18 and nitrogen-13 labeled compounds presented are of particular value to scientists working in this field. Two appendices are also included to provide supplementary general references. A subject index concludes this volume.

  5. (68) Ga-labeled Ciprofloxacin Conjugates as Radiotracers for Targeting Bacterial Infection.

    Science.gov (United States)

    Satpati, Drishty; Arjun, Chanda; Krishnamohan, Repaka; Samuel, Grace; Banerjee, Sharmila

    2016-05-01

    With an aim of developing a bacteria-specific molecular imaging agent, ciprofloxacin has been modified with a propylamine spacer and linked to two common bifunctional chelators, p-SCN-Bz-DOTA and p-SCN-Bz-NOTA. The two ciprofloxacin conjugates, CP-PA-SCN-Bz-DOTA (1) and CP-PA-SCN-Bz-NOTA (2), were radiolabeled with (68)Ga in >90% radiochemical yield and were moderately stable in vitro for 4 h. The efficacy of (68)Ga-1 and (68)Ga-2 has been investigated in vitro in Staphylococcus aureus cells where bacterial binding of the radiotracers (0.9-1.0% for (68)Ga-1 and 1.6-2.3% for (68)Ga-2) could not be blocked in the presence of excess amount of unlabeled ciprofloxacin. However, uptake of radiotracers in live bacterial cells was significantly higher (p 68)Ga-1 and (68)Ga-2 was tested in vivo in rats where the infected muscle-to-inflamed muscle ((68)Ga-1: 2 ± 0.2, (68)Ga-2: 3 ± 0.5) and infected muscle-to-normal muscle ratios ((68)Ga-1: 3 ± 0.4, (68)Ga-2: 6.6 ± 0.8) were found to improve at 120 min p.i. Fast blood clearance and renal excretion was observed for both the radiotracers. The two (68)Ga-labeled infection targeting radiotracers could discriminate between bacterial infection and inflammation in vivo and are worthy of further detailed investigation as infection imaging agents at the clinical level.

  6. Environmental biochemistry of current environmental levels of heavy metals: preparation of radiotracers with very high specific radioactivity for metallobiochemical experiments on laboratory animals.

    Science.gov (United States)

    Sabbioni, E; Goetz, L; Birattari, C; Bonardi, M

    1981-03-01

    Environmental toxicology research on dose-response relationships of heavy metals requires experiments on laboratory animals exposed to "low doses" of trace elements which should reflect "present or actual environmental levels" characteristic of polluted environments. Unfortunately no criteria exist to establish the "low doses" to which laboratory animals must be exposed, in practice the choice of the level used is made in an almost arbitrary manner. In order to define the "present environmental levels" of heavy metals which should be administered to laboratory animals an approach is suggested, based upon knowledge of the concentrations of trace elements in the diet, air and food as well as the fractions absorbed. Today daily intakes of trace elements by man are of the order of few micrograms or nanograms thus requiring the use of extremely sensitive analytical techniques to determine the very low amounts of heavy metals in tissues and cellular components. In these fields of research the use of radiotracers with very high specific radioactivity appears particularly advantageous but requires considerable care during their preparation and use. The first part of this paper deals with a definition of the ranges of concentrations of trace elements which should be used for metabolic studies on laboratory animals when they are exposed via different routes such as ingestion, inhalation in injection; the second part describes the production of radiotracers with very high specific radioactivity by proton activation in the cyclotron and by neutron irradiation in the nuclear reactor. Their use to label present levels of heavy metals under conditions adapted for biochemical purposes, as well as the preparation of different metal-labelled chemical species is also reported. Particular attention is directed to quality control of the radiotracer solutions which are administered to the animals including those of radioactivity concentrations, radioisotopic purity, radiochemical purity

  7. Synthesis and Biological Evaluation of Thiophene-Based Cannabinoid Receptor Type 2 Radiotracers for PET Imaging

    Directory of Open Access Journals (Sweden)

    Ahmed Haider

    2016-07-01

    Full Text Available Over the past two decades, our understanding of the endocannabinoid system has greatly improved due to the wealth of results obtained from exploratory studies. Currently, two cannabinoid receptor subtypes have been well characterized. The cannabinoid receptor type 1 (CB1 is widely expressed in the central nervous system, while the levels of the cannabinoid receptor type 2 (CB2 in the brain and spinal cord of healthy individuals are relatively low. However, recent studies demonstrated a CB2 upregulation on activated microglia upon neuroinflammation, an indicator of neurodegeneration. Our research group aims to develop a suitable positron emission tomography (PET tracer to visualize the CB2 receptor in patients suffering from neurodegenerative diseases. Herein we report two novel thiophene-based 11C-labeled PET ligands designated [11C]AAT-015 and [11C]AAT-778. The reference compounds were synthesized using Gewald reaction conditions to obtain the aminothiophene intermediates, followed by amide formation. Saponification of the esters provided their corresponding precursors. Binding affinity studies revealed Ki values of 3.3 ± 0.5 nM (CB2 and 1.0 ± 0.2 µM (CB1 for AAT-015. AAT-778 showed similar Ki values of 4.3 ± 0.7 nM (CB2 and 1.1 ± 0.1 µM (CB1. Radiosynthesis was carried out under basic conditions using [11C]iodomethane as methylating agent. After semi-preparative HPLC purification both radiolabeled compounds were obtained in 99% radiochemical purity and the radiochemical yields ranged from 12 to 37%. Specific activity was between 96 - 449 GBq/µmol for both tracers. In order to demonstrate CB2 specificity of [11C]AAT-015 and [11C]AAT-778, we carried out autoradiography studies using CB2-positive mouse/rat spleen tissues. The obtained results revealed unspecific binding in spleen tissue that was not blocked by an excess of CB2-specific ligand GW402833. For in vivo analysis, [11C]AAT-015 was administered to healthy rats via tail

  8. Synthesis and Biological Evaluation of Thiophene-Based Cannabinoid Receptor Type 2 Radiotracers for PET Imaging

    Science.gov (United States)

    Haider, Ahmed; Müller Herde, Adrienne; Slavik, Roger; Weber, Markus; Mugnaini, Claudia; Ligresti, Alessia; Schibli, Roger; Mu, Linjing; Mensah Ametamey, Simon

    2016-01-01

    Over the past two decades, our understanding of the endocannabinoid system has greatly improved due to the wealth of results obtained from exploratory studies. Currently, two cannabinoid receptor subtypes have been well-characterized. The cannabinoid receptor type 1 (CB1) is widely expressed in the central nervous system, while the levels of the cannabinoid receptor type 2 (CB2) in the brain and spinal cord of healthy individuals are relatively low. However, recent studies demonstrated a CB2 upregulation on activated microglia upon neuroinflammation, an indicator of neurodegeneration. Our research group aims to develop a suitable positron emission tomography (PET) tracer to visualize the CB2 receptor in patients suffering from neurodegenerative diseases. Herein we report two novel thiophene-based 11C-labeled PET ligands designated [11C]AAT-015 and [11C]AAT-778. The reference compounds were synthesized using Gewald reaction conditions to obtain the aminothiophene intermediates, followed by amide formation. Saponification of the esters provided their corresponding precursors. Binding affinity studies revealed Ki-values of 3.3 ± 0.5 nM (CB2) and 1.0 ± 0.2 μM (CB1) for AAT-015. AAT-778 showed similar Ki-values of 4.3 ± 0.7 nM (CB2) and 1.1 ± 0.1 μM (CB1). Radiosynthesis was carried out under basic conditions using [11C]iodomethane as methylating agent. After semi-preparative HPLC purification both radiolabeled compounds were obtained in 99% radiochemical purity and the radiochemical yields ranged from 12 to 37%. Specific activity was between 96 and 449 GBq/μmol for both tracers. In order to demonstrate CB2 specificity of [11C]AAT-015 and [11C]AAT-778, we carried out autoradiography studies using CB2-positive mouse/rat spleen tissues. The obtained results revealed unspecific binding in spleen tissue that was not blocked by an excess of CB2-specific ligand GW402833. For in vivo analysis, [11C]AAT-015 was administered to healthy rats via tail-vein injection

  9. Synthesis of n. c. a. PET-radiotracers with carbon-11. Zur Synthese traegerarme PET-Radiotracer mit Kohlenstoff-11

    Energy Technology Data Exchange (ETDEWEB)

    Schirbel, A.

    1998-11-01

    Carbon-11 offers the unique possibility of authentic labelling of molecules as radioindicators for non invasive and quantitative determination of physiological functions via positron emission tomography (PET). Therefore, the goal of this thesis was to synthesize of different n.c.a. [sup 11]C-labelled pharmaceuticals for in vivo distribution studies with PET. For the determination of the pharmacokinetics of [1-[sup 11]C]acetate in porcine myocardium during prolonged ischemia, n.c.a. [1-[sup 11]C]acetate was synthesized via carboxylation of methylmagnesium bromide with in target produced n.c.a. [[sup 11]C]CO[sub 2] with a radiochemical yield (RCY) of 68 [+-] 7%. The fast (18 min) and reliable radiosynthesis allowed for repeated tracer administration at short intervals (<20 min). In order to study the pharmacokinetics and metabolism of acetylsalicylic acid (Aspirin[sup R]c) in humans, [1-[sup 11]C]acetylsalicylic acid, acetyl-[carboxy-[sup 11]C]salicylic acid and [carboxy-[sup 11]C]salicylic acid were prepared. N.c.a. [1-[sup 11]C]acetylsalicylic acid was synthesized via the reaction of [1-[sup 11]C]acetylchloride with salicylic acid salts. The use of the silver salt proved to be superior to the sodium salt and resulted in radiochemical yields of 32 [+-] 5%. Base-line (clean) separation of the labelled product was achieved using radio-HPLC. With regard to the preparation of n.c.a. [carboxy-[sup 11]C]salicylic acid, several protected and unprotected phenol derivates were metallated and subsequently carboxylated using n.c.a. [[sup 11]C]CO[sub 2]. Best results (87 [+-] 3% RCY) could be achieved with 2-(methoxymethoxy)-phenylmagnesium iodide as a precursor and subsequent quantitative cleavage of the MOM-group. Acetylation of n.c.a. [carboxy-[sup 11]C]salicylic acid to acetyl-[carboxy-[sup 11]C]salicylic acid was performed using acetylchloride in CH[sub 2]Cl[sub 2] with a radiochemical yield of 65 [+-] 4%. (orig.)

  10. Mercury methylation and reduction potentials in marine water: An improved methodology using {sup 197}Hg radiotracer

    Energy Technology Data Exchange (ETDEWEB)

    Koron, Neza [National Institute of Biology, Marine Biology Station, Fornace 41, 6330 Piran (Slovenia); Bratkic, Arne [Department of Environmental Sciences, ' Jozef Stefan' Institute, Jamova 39, 1000 Ljubljana (Slovenia); Ribeiro Guevara, Sergio, E-mail: ribeiro@cab.cnea.gov.ar [Laboratorio de Analisis por Activacion Neutronica, Centro Atomico Bariloche, Av. Bustillo km 9.5, 8400 Bariloche (Argentina); Vahcic, Mitja; Horvat, Milena [Department of Environmental Sciences, ' Jozef Stefan' Institute, Jamova 39, 1000 Ljubljana (Slovenia)

    2012-01-15

    A highly sensitive laboratory methodology for simultaneous determination of methylation and reduction of spiked inorganic mercury (Hg{sup 2+}) in marine water labelled with high specific activity radiotracer ({sup 197}Hg prepared from enriched {sup 196}Hg stable isotope) was developed. A conventional extraction protocol for methylmercury (CH{sub 3}Hg{sup +}) was modified in order to significantly reduce the partitioning of interfering labelled Hg{sup 2+} into the final extract, thus allowing the detection of as little as 0.1% of the Hg{sup 2+} spike transformed to labelled CH{sub 3}Hg{sup +}. The efficiency of the modified CH{sub 3}Hg{sup +} extraction procedure was assessed by radiolabelled CH{sub 3}Hg{sup +} spikes corresponding to concentrations of methylmercury between 0.05 and 4 ng L{sup -1}. The recoveries were 73.0{+-}6.0% and 77.5{+-}3.9% for marine and MilliQ water, respectively. The reduction potential was assessed by purging and trapping the radiolabelled elemental Hg in a permanganate solution. The method allows detection of the reduction of as little as 0.001% of labelled Hg{sup 2+} spiked to natural waters. To our knowledge, the optimised methodology is among the most sensitive available to study the Hg methylation and reduction potential, therefore allowing experiments to be done at spikes close to natural levels (1-10 ng L{sup -1}). - Highlights: Black-Right-Pointing-Pointer Inorganic mercury methylation and reduction in marine water were studied. Black-Right-Pointing-Pointer High specific activity {sup 197}Hg was used to label Hg{sup 2+} spikes at natural levels. Black-Right-Pointing-Pointer Methylmercury extraction had 73% efficiency for 0.05-4 ng L{sup -1} levels. Black-Right-Pointing-Pointer High sensibility to assess methylation potentials, below 0.1% of the spike. Black-Right-Pointing-Pointer High sensibility also for reduction potentials, as low as 0.001% of the spike.

  11. Applications of Beta Particle Detection for Synthesis and Usage of Radiotracers Developed for Positron Emission Tomography

    Science.gov (United States)

    Dooraghi, Alex Abreu

    Positron Emission Tomography (PET) is a noninvasive molecular imaging tool that requires the use of a radioactive compound or radiotracer which targets a molecular pathway of interest. We have developed and employed three beta particle radiation detection systems to advance PET. Specifically, the goals of these systems are to: 1. Automate dispensing of solutions containing a positron emitting isotope. 2. Monitor radioactivity on-chip during synthesis of a positron emitting radiotracer. 3. Assay cellular uptake on-chip of a positron emitting radiotracer. Automated protocols for measuring and dispensing solutions containing radioisotopes are essential not only for providing an optimum environment for radiation workers, but also to ensure a quantitatively accurate workflow. For the first project, we describe the development and performance of a system for automated radioactivity distribution of beta particle emitting radioisotopes such as fluorine-18 (F-18). Key to the system is a radiation detector in-line with a peristaltic pump. The system demonstrates volume accuracy within 5 % for volumes of 20 muL or greater. When considering volumes of 20 muL or greater, delivered radioactivity is in agreement with the requested radioactivity as measured with the dose calibrator. The integration of the detector and pump leads to a flexible system that can accurately dispense solutions containing F-18 in radioactivity concentrations directly produced from a cyclotron (~ 0.1-1 mCi/muL), to low activity concentrations intended for preclinical mouse scans (~ 1-10 muCi/muL), and anywhere in between. Electrowetting on dielectric (EWOD) is an attractive microfluidic platform for batch synthesis of PET radiotracers. Visualization of radioisotopes on-chip is critical for synthesis optimization and technological development. For the second project, we describe the development and performance of a Cerenkov/real-time imaging system for PET radiotracer synthesis on EWOD. We also investigate

  12. Transmutation products may influence radiotracer diffusion rates in an ionic solid.

    Science.gov (United States)

    Wei, G C; Wuensch, B J

    1977-07-08

    An inherent aspect of radiotracer diffusion is that alpha, beta(+), or beta(-) emission produces a daughter element of different ionization state. This process must either cause a change in the vacancy concentrations or create space charge, depending on the effectiveness of the internal sources or sinks. Four coupled equations established to model the kinetics, when solved by numerical methods, predict that the apparent tracer diffusion rate may easily be in error by a factor of 2 or 3 and, under certain conditions, by as much as an order of magnitude.

  13. New starch-based radiotracer for lung perfusion scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Lacoeuille, Franck; Couturier, Olivier; Le Jeune, Jean Jacques [University of Angers, Inserm U646, Angers (France); University Hospital of Angers, Nuclear Medicine Department, Angers (France); Hindre, Francois; Denizot, Benoit; Benoit, Jean Pierre [University of Angers, Inserm U646, Angers (France); Bouchet, Francis [University Hospital of Angers, Nuclear Medicine Department, Angers (France); Legras, Pierre [University of Angers, SCAHU, UFR Medecine, Angers (France); Askienazy, Serge [Biopole Clermont Limagne, Cyclopharma Laboratoires, F-63 Saint-Beauzire (France)

    2010-01-15

    In order to avoid the microbiological risks linked to human serum albumin macroaggregates (MAA) used for lung perfusion scintigraphy, we developed a new starch-based Tc-99m potential radiopharmaceutical. Microparticles were prepared from oxidised starch coupled to natural polyamine for Tc-99m complexation. Suspensions were formulated as ready-to-use kits for easy one-step labelling procedures. Particle-size analysis, electron microscopy, and confocal microscopy were performed for microparticle characterisation, and gave a typical size distribution ranging from 7 to 63 {mu}m, with a homogenous population of spherical or oval-shaped microparticles. Radiochemical purity exceeded 95%, and was stable for at least 8 h. When challenged with histidine and human plasma, labelling was also stable. Dynamic scintigraphic acquisitions and biodistribution studies conducted on healthy Wistar rats showed a tracer accumulation with more than 80% of the ID in the lungs after 15 min. With clinically significant characteristics such as a lung half-life of 3 h, a lung-to-vascular ratio of 900, and a lung-to-liver ratio of 90, starch-based microparticles exhibit all the qualities for an effective new lung perfusion agent. (orig.)

  14. Comparison of DMSA Scan 99 m and EC Scan 99 m in Diagnosis of Cortical Defect and Differential Renal Function

    OpenAIRE

    Mohammadi-Fallah, M.; Alizadeh, M.; Lavin, T. Ahmadi

    2014-01-01

    Introduction: Diagnosis of renal cortical lesions by radioisotopes in nuclear medicine is one of the most common techniques and procedures can be performed by different radiotracer. However, all these materials are accurate in determining kidney function, but there are differences between them in the field. The purpose of this study was to evaluate the effectiveness of EC scans compared with DMSA scan in the detection of cortical lesions and DRF. Methods: 65 cases, which have been referred fo...

  15. Managing Lymphoma with Non-FDG Radiotracers: Current Clinical and Preclinical Applications

    Directory of Open Access Journals (Sweden)

    Fan-Lin Kong

    2013-01-01

    Full Text Available Nuclear medicine imaging modalities such as positron emission tomography (PET and single-photon emission computed tomography (SPECT have played a prominent role in lymphoma management. PET with [18F]Fluoro-2-deoxy-D-glucose (FDG is the most commonly used tool for lymphoma imaging. However, FDG-PET has several limitations that give the false positive or false negative diagnosis of lymphoma. Therefore, development of new radiotracers with higher sensitivity, specificity, and different uptake mechanism is in great demand in the management of lymphoma. This paper reviews non-FDG radiopharmaceuticals that have been applied for PET and SPECT imaging in patients with different types of lymphoma, with attention to diagnosis, staging, therapy response assessment, and surveillance for disease relapse. In addition, we introduce three radiolabeled anti-CD20 antibodies for radioimmunotherapy, which is another important arm for lymphoma treatment and management. Finally, the relatively promising radiotracers that are currently under preclinical development are also discussed in this paper.

  16. [(18)F]6-fluoro-3,4-dihydroxy-L-phenylalanine--recent modern syntheses for an elusive radiotracer.

    Science.gov (United States)

    Edwards, Richard; Wirth, Thomas

    2015-05-15

    [(18)F]6-fluoro-3,4-dihydroxy-L-phenylalanine ([(18)F]F-DOPA) has been known to be a useful radiotracer for over 30 years. Its widespread clinical use has been hampered by the lack of a robust, high yielding synthesis. This review summarises new developments in radiochemistry that are providing solutions to long standing problems involved in the synthesis of this important but elusive radiotracer. Considerable advances in nucleophilic synthesis have been achieved by optimising multistep strategies and using both hypervalent iodine chemistry and transition metal-mediated fluorinations allowing for the production of high specific activity [(18)F]F-DOPA.

  17. Potential therapeutic radiotracers: preparation, biodistribution and metabolic characteristics of 177Lu-labeled cyclic RGDfK dimer.

    Science.gov (United States)

    Shi, Jiyun; Liu, Zhaofei; Jia, Bing; Yu, Zilin; Zhao, Huiyun; Wang, Fan

    2010-06-01

    In this study, we reported the preparation and evaluation of (177)Lu-DOTA-RGD2, (177)Lu-DOTA-Bz-RGD2 and (177)Lu-DTPA-Bz-RGD2 (RGD2 = E[c(RGDfK)](2)) as a potential therapeutic radiotracers for the treatment of integrin alpha(v)beta(3)-positive tumors. The BALB/c nude mice bearing the U87MG human glioma xenografts were used to evaluate the biodistribution characteristics and excretion kinetics of (177)Lu-DOTA-RGD2, (177)Lu-DOTA-Bz-RGD2 and (177)Lu-DTPA-Bz-RGD2. It was found that there were no major differences in their lipophilicity and biodistribution characteristics, particularly at latter time points. A major advantage of using DTPA-Bz as the bifunctional chelator (BFC) was its high radiolabeling efficiency (fast and high yield radiolabeling) at room temperature. Using DOTA and DOTA-Bz as BFCs, the radiolabeling kinetics was slow, and heating at 100 degrees C and higher DOTA-conjugate concentration were needed for successful (177)Lu-labeling. Therefore, DTPA-Bz is an optimal BFC for routine preparation of (177)Lu-labeled cyclic RGDfK peptides, and (177)Lu-DTPA-Bz-RGD2 is worthy of further investigation for targeted radiotherapy of integrin alpha(v)beta(3)-positive tumors.

  18. Optimizing tumor targeting of the lipophilic EGFR-binding radiotracer SKI 243 using a liposomal nanoparticle delivery system.

    Science.gov (United States)

    Medina, Oula Penate; Pillarsetty, Nagavarakishore; Glekas, Athanasios; Punzalan, Blesida; Longo, Valerie; Gönen, Mithat; Zanzonico, Pat; Smith-Jones, Peter; Larson, Steven M

    2011-02-10

    Positron emission tomography (PET) of epidermal growth factor receptor (EGFR) kinase-specific radiolabeled tracers could provide a means for non-invasively characterizing EGFR expression and signaling activity in patients' tumors before, during, and after therapy with EGFR inhibitors. Towards this goal, our group has developed PET tracers which irreversibly bind to EGFR. However, tumor uptake is relatively low because of both the lipophilicity of such tracers (e.g. the morpholino-[124I]-IPQA [SKI 212243]), with octanol-to-water partition coefficients of up to 4, and a short dwell time in the blood and significant hepatobiliary clearance and intestinal reuptake. Liposomal nanoparticle delivery systems may favorably alter the pharmacokinetic profile and improve tumor targeting of highly lipophilic but otherwise promising cancer imaging tracers, such as the EGFR inhibitor SKI 243. SKI 243 is therefore an interesting model molecule for incorporation into lipid-based nanoparticles, as it would not only improve their solubility but also increase the circulation time, availability and, potentially, targeting of tumors. In the current study, we compared the pharmacokinetics and tumor targeting of the bare EGFR kinase-targeting radiotracer SKI 212243 (SKI 243) with that of the same tracer embedded in liposomes. SKI 243 and liposomal SKI 243 are both taken up by tumor xenografts but liposomal SKI 243 remained in the blood longer and consequently exhibited a 3- to 6-fold increase in uptake in the tumor among several other organs.

  19. Functional Disorders in Neurology : Case Studies

    NARCIS (Netherlands)

    Stone, Jon; Hoeritzauer, Ingrid; Gelauff, Jeannette; Lehn, Alex; Gardiner, Paula; van Gils, Anne; Carson, Alan

    Functional, often called psychogenic, disorders are common in neurological practice. We illustrate clinical issues and highlight some recent research findings using six case studies of functional neurological disorders. We discuss dizziness as a functional disorder, describing the relatively new

  20. A Density Functional Theory Study

    KAUST Repository

    Lim, XiaoZhi

    2011-12-11

    Complexes with pincer ligand moieties have garnered much attention in the past few decades. They have been shown to be highly active catalysts in several known transition metal-catalyzed organic reactions as well as some unprecedented organic transformations. At the same time, the use of computational organometallic chemistry to aid in the understanding of the mechanisms in organometallic catalysis for the development of improved catalysts is on the rise. While it was common in earlier studies to reduce computational cost by truncating donor group substituents on complexes such as tertbutyl or isopropyl groups to hydrogen or methyl groups, recent advancements in the processing capabilities of computer clusters and codes have streamlined the time required for calculations. As the full modeling of complexes become increasingly popular, a commonly overlooked aspect, especially in the case of complexes bearing isopropyl substituents, is the conformational analysis of complexes. Isopropyl groups generate a different conformer with each 120 ° rotation (rotamer), and it has been found that each rotamer typically resides in its own potential energy well in density functional theory studies. As a result, it can be challenging to select the most appropriate structure for a theoretical study, as the adjustment of isopropyl substituents from a higher-energy rotamer to the lowest-energy rotamer usually does not occur during structure optimization. In this report, the influence of the arrangement of isopropyl substituents in pincer complexes on calculated complex structure energies as well as a case study on the mechanism of the isomerization of an iPrPCP-Fe complex is covered. It was found that as many as 324 rotamers can be generated for a single complex, as in the case of an iPrPCP-Ni formato complex, with the energy difference between the global minimum and the highest local minimum being as large as 16.5 kcalmol-1. In the isomerization of a iPrPCP-Fe complex, it was found

  1. Improving the stability of peptidic radiotracers by the introduction of artificial scaffolds: which structure element is most useful?

    Science.gov (United States)

    Bacher, Lisa; Fischer, Gabriel; Litau, Shanna; Schirrmacher, Ralf; Wängler, Björn; Baller, Marko; Wängler, Carmen

    2015-08-01

    Peptidic radiotracers are highly potent substances for the specific in vivo imaging of various biological targets with Single Photon Emission Computed Tomography and Positron Emission Tomography. However, some radiolabeled peptides such as bombesin analogs were shown to exhibit only a limited stability, hampering a successful target visualization. One option to positively influence the stability of radiolabeled peptides is the introduction of certain artificial molecular scaffolds. In order to comparatively assess the influence of different structure elements on the stability of radiolabeled peptides and to identify those structure elements being most useful for peptide radiotracer stabilization, several monomeric and dimeric bombesin derivatives were synthesized, exhibiting differing molecular designs and the chelator NODAGA for (68) Ga-labeling. The radiolabeled peptides were evaluated regarding their in vitro stability in human serum to determine the influence of the introduced molecular scaffolds on the peptides' serum stabilities. The results of the evaluations showed that the introduction of scaffold structures and the overall molecular design have a substantial impact on the stabilities of the resulting peptidic radiotracers. But besides some general trends found using certain scaffold structures, the obtained results point to the necessity to empirically assess their influence on stability for each susceptible peptidic radiotracer individually.

  2. Metabolite identification of a radiotracer by electrochemistry coupled to liquid chromatography with mass spectrometric and radioactivity detection.

    Science.gov (United States)

    Baumann, Anne; Faust, Andreas; Law, Marylin P; Kuhlmann, Michael T; Kopka, Klaus; Schäfers, Michael; Karst, Uwe

    2011-07-01

    Radioligands, which specifically bind to a receptor or enzyme (target), enable molecular imaging of the target expression by positron emission tomography (PET). One very promising PET tracer is (S)-1-(4-(2-[(18)F]-fluoroethoxy)benzyl)-5-[1-(2-methoxymethylpyrrolidinyl)sulfonyl]isatin (isatin), a caspase-3 inhibitor, which has been developed at the University Hospital of Münster to image cell death (apoptosis). The translation of this novel tracer from preclinical evaluation to clinical examinations requires biodistribution studies, which characterize the pharmakodynamics and metabolic fate of the compound. This information is used to further optimize the radioligands and to interpret radioactive signals from tissues upon injection of the radioligand in vivo with respect to their specificity. The analysis of the metabolism of radioligands is hampered by the low amount of the compound being typically injected (nano/picomolar amount per injection). In the present study, electrochemistry (EC) is applied to elucidate the oxidative metabolism pathway of the radiotracer. Previous studies have demonstrated that EC can be utilized as a complementary tool to conventional in vitro approaches in drug metabolism studies. Thereby, potential oxidative metabolites of the isatin are determined by EC coupled to electrospray ionization mass spectrometry (EC/ESI-MS). Moreover, using EC/liquid chromatography (LC) and ESI-ion trap MS(n), structural elucidation of the oxidation products is performed. Comparatively to EC, in vitro metabolism studies with rat liver microsomes are conducted. Finally, the developed LC/ESI-MS method is applied to determine metabolites in body fluids and cell extracts from in vivo studies with the nonradioactive ((19)F) and radioactive isatin ((18)F). On the basis of the electrochemically generated oxidation products of the radioligand, the major radioactive metabolite occurring in vivo was successfully identified.

  3. Predicting future morphological changes of lesions from radiotracer uptake in 18F-FDG-PET images.

    Directory of Open Access Journals (Sweden)

    Ulas Bagci

    Full Text Available We introduce a novel computational framework to enable automated identification of texture and shape features of lesions on (18F-FDG-PET images through a graph-based image segmentation method. The proposed framework predicts future morphological changes of lesions with high accuracy. The presented methodology has several benefits over conventional qualitative and semi-quantitative methods, due to its fully quantitative nature and high accuracy in each step of (i detection, (ii segmentation, and (iii feature extraction. To evaluate our proposed computational framework, thirty patients received 2 (18F-FDG-PET scans (60 scans total, at two different time points. Metastatic papillary renal cell carcinoma, cerebellar hemongioblastoma, non-small cell lung cancer, neurofibroma, lymphomatoid granulomatosis, lung neoplasm, neuroendocrine tumor, soft tissue thoracic mass, nonnecrotizing granulomatous inflammation, renal cell carcinoma with papillary and cystic features, diffuse large B-cell lymphoma, metastatic alveolar soft part sarcoma, and small cell lung cancer were included in this analysis. The radiotracer accumulation in patients' scans was automatically detected and segmented by the proposed segmentation algorithm. Delineated regions were used to extract shape and textural features, with the proposed adaptive feature extraction framework, as well as standardized uptake values (SUV of uptake regions, to conduct a broad quantitative analysis. Evaluation of segmentation results indicates that our proposed segmentation algorithm has a mean dice similarity coefficient of 85.75 ± 1.75%. We found that 28 of 68 extracted imaging features were correlated well with SUV(max (p<0.05, and some of the textural features (such as entropy and maximum probability were superior in predicting morphological changes of radiotracer uptake regions longitudinally, compared to single intensity feature such as SUV(max. We also found that integrating textural features with

  4. H-CRRETAWAC-OH, a Lead Structure for the Development of Radiotracer Targeting Integrin α5β1?

    Directory of Open Access Journals (Sweden)

    Roland Haubner

    2014-01-01

    Full Text Available Imaging of angiogenic processes is of great interest in preclinical research as well as in clinical settings. The most commonly addressed target structure for imaging angiogenesis is the integrin αvβ3. Here we describe the synthesis and evaluation of [18F]FProp-Cys*-Arg-Arg-Glu-Thr-Ala-Trp-Ala-Cys*-OH, a radiolabelled peptide designed to selectively target the integrin α5β1. Conjugation of 4-nitrophenyl-(RS-2-[18F]fluoropropionate provided [18F]FProp-Cys*-Arg-Arg-Glu-Thr-Ala-Trp-Ala-Cys*-OH in high radiochemical purity (>95% and a radiochemical yield of approx. 55%. In vitro evaluation showed α5β1 binding affinity in the nanomolar range, whereas affinity to αvβ3 and αIIbβ3 was >50 μM. Cell uptake studies using human melanoma M21 (αvβ3-positive and α5β1-negative, human melanoma M21-L (αvβ3-negative and α5β1-negative, and human prostate carcinoma DU145 (αvβ3-negative and α5β1-positive confirmed receptor-specific binding. The radiotracer was stable in human serum and showed low protein binding. Biodistribution studies showed tumour uptake ranging from 2.5 to 3.5% ID/g between 30 and 120 min post-injection. However, blocking studies and studies using mice bearing α5β1-negative M21 tumours did not confirm receptor-specific uptake of [18F]FProp-Cys*-Arg-Arg-Glu-Thr-Ala-Trp-Ala-Cys*-OH, although this radiopeptide revealed high affinity and substantial selectivity to α5β1 in vitro. Further experiments are needed to study the in vivo metabolism of this peptide and to develop improved radiopeptide candidates suitable for PET imaging of α5β1 expression in vivo.

  5. Radioiodinated 2-hydroxy-3-(4-iodophenyl)-1-(4-phenylpiperidinyl)propane: potential radiotracer for mapping central cholinergic innervation in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Efange, S.M.N.; Dutta, A.K.; Michelson, R.H.; Thomas, J.R.; Boudreau, R.J. (Minnesota Univ., Minneapolis, MN (United States)); Kung, H.F.; Billings, J. (Pennsylvania Univ., Philadelphia, PA (United States). Dept. of Radiology)

    1992-04-01

    Radioiodinated 2-hydroxy-3-(4-iodophenyl)-1-(4-phenylpiperidinyl)propane, (4-HIPP), was synthesized and evaluated as a simple vesamicol-like radiotracer for mapping cholinergic pathways in the brain. Both enantiomers of 4-HIPP exhibit significant accumulation (approx. 2% of injected dose) and prolonged retention (t[sub 1/2] > 3h) within the rat brain. The accumulation of radioiodinated 4-HIPP in the rat brain was reduced by up to 70% in the presence of vesamicol and its analogs. The levorotary isomer (-)-4-[[sup 123]I]HIPP exhibits significant accumulation in the monkey brain, with a half-life of about 9 h. Radioiodinated 4-HIPP may therefore be a useful tool for studying cholinergic pathways in the brain. (author).

  6. SPECT imaging with the serotonin transporter radiotracer [{sup 123}I]p ZIENT in nonhuman primate brain

    Energy Technology Data Exchange (ETDEWEB)

    Cosgrove, Kelly P., E-mail: kelly.cosgrove@yale.ed [Yale University School of Medicine, VA Connecticut HCS (116A6), West Haven, CT 06516 (United States); Staley, Julie K.; Baldwin, Ronald M.; Bois, Frederic [Yale University School of Medicine, VA Connecticut HCS (116A6), West Haven, CT 06516 (United States); Plisson, Christophe [Emory University School of Medicine, Atlanta, GA 30322 (United States); Al-Tikriti, Mohammed S. [Yale University School of Medicine, VA Connecticut HCS (116A6), West Haven, CT 06516 (United States); Seibyl, John P. [Institute for Neurodegenerative Disorders, New Haven, CT 06510 (United States); Goodman, Mark M. [Emory University School of Medicine, Atlanta, GA 30322 (United States); Tamagnan, Gilles D. [Yale University School of Medicine, VA Connecticut HCS (116A6), West Haven, CT 06516 (United States); Institute for Neurodegenerative Disorders, New Haven, CT 06510 (United States)

    2010-07-15

    Introduction: Serotonin dysfunction has been linked to a variety of psychiatric diseases; however, an adequate SPECT radioligand to probe the serotonin transporter system has not been successfully developed. The purpose of this study was to characterize and determine the in vivo selectivity of iodine-123-labeled 2{beta}-carbomethoxy-3{beta}-(4'-((Z)-2-iodoethenyl)phenyl)nortropane, [{sup 123}I]p ZIENT, in nonhuman primate brain. Methods: Two ovariohysterectomized female baboons participated in nine studies (one bolus and eight bolus to constant infusion at a ratio of 9.0 h) to evaluate [{sup 123}I]p ZIENT. To evaluate the selectivity of [{sup 123}I]p ZIENT, the serotonin transporter blockers fenfluramine (1.5, 2.5 mg/kg) and citalopram (5 mg/kg), the dopamine transporter blocker methylphenidate (0.5 mg/kg) and the norepinephrine transporter blocker nisoxetine (1 mg/kg) were given at 8 h post-radiotracer injection. Results: In the bolus to constant infusion studies, equilibrium was established by 4-8 h. [{sup 123}I]p ZIENT was 93% and 90% protein bound in the two baboons and there was no detection of lipophilic radiolabeled metabolites entering the brain. In the high-density serotonin transporter regions (diencephalon and brainstem), fenfluramine and citalopram resulted in 35-71% and 129-151% displacement, respectively, whereas methylphenidate and nisoxetine did not produce significant changes (<10%). Conclusion: These findings suggest that [{sup 123}I]p ZIENT is a favorable compound for in vivo SPECT imaging of serotonin transporters with negligible binding to norepinephrine and dopamine transporters.

  7. Investigating the pharmacokinetics and biological distribution of silver-loaded polyphosphoester-based nanoparticles using (111) Ag as a radiotracer.

    Science.gov (United States)

    Aweda, Tolulope A; Zhang, Shiyi; Mupanomunda, Chiedza; Burkemper, Jennifer; Heo, Gyu Seong; Bandara, Nilantha; Lin, Mai; Cutler, Cathy S; Cannon, Carolyn L; Youngs, Wiley J; Wooley, Karen L; Lapi, Suzanne E

    2015-05-30

    Purified (111) Ag was used as a radiotracer to investigate silver loading and release, pharmacokinetics, and biodistribution of polyphosphoester-based degradable shell crosslinked knedel-like (SCK) nanoparticles as a comparison to the previously reported small molecule, N-heterocyclic silver carbene complex analog (SCC1) for the delivery of therapeutic silver ions in mouse models. Biodistribution studies were conducted by aerosol administration of (111) Ag acetate, [(111) Ag]SCC1, and [(111) Ag]SCK doses directly into the lungs of C57BL/6 mice. Nebulization of the (111) Ag antimicrobials resulted in an average uptake of 1.07 ± 0.12% of the total aerosolized dose given per mouse. The average dose taken into the lungs of mice was estimated to be 2.6 ± 0.3% of the dose inhaled per mouse for [(111) Ag]SCC1 and twice as much dose was observed for the [(111) Ag]SCKs (5.0 ± 0.3% and 5.9 ± 0.8% for [(111) Ag]aSCK and [(111) Ag]zSCK, respectively) at 1 h post administration (p.a.). [(111) Ag]SCKs also exhibited higher dose retention in the lungs; 62-68% for [(111) Ag]SCKs and 43% for [(111) Ag]SCC1 of the initial 1 h dose were observed in the lungs at 24 h p.a.. This study demonstrates the utility of (111) Ag as a useful tool for monitoring the pharmacokinetics of silver-loaded antimicrobials in vivo.

  8. [{sup 67}Ga]Gallium-complex with 2-acetylpyridine N4-ortho fluorophenylthiosemicarbazone as a radiotracer for brain tumor diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Pesquero, Jorge L. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Fisiologia e Biofisica; Pujatti, Priscilla B.; Araujo, Elaine B. de [Instituto de Pesquisas Energeticas Nucleares (DIRF/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Diretoria de Radiofarmacia; Lessa, Josane A.; Beraldo, Heloisa [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Quimica; Soares, Marcella A.; Santos, Raquel G. dos, E-mail: santosr@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2011-07-01

    The aim of this work was to develop a {sup 67}Ga-based SPECT imaging agent derived from 2-acetylpyridine N4-orthofluorophenyl - thiosemicarbazone (PhoF). For this purpose, PhoF was radiolabeled using {sup 67}Ga as radiotracer, and after quality control analysis its biodistribution and SPECT imaging were evaluated on Swiss mice and Nude mice bearing glioblastoma multiform tumor (U87-MG). The labelling of PhoF with {sup 67}GaCl{sub 3} was performed in methanol for 30 minutes at room temperature. Radiochemical analyses were done by HPLC with radioactivity detection. {sup 67}Ga- PhoF was successful produced with 97.5 {+-} 0.6% of radiochemical purity and high specific activity (1.0 TBq /mmol). {sup 67}Ga- PhoF showed to be a stable compound keeping its stability, when stored at 2-4 deg C. In biodistribution studies, {sup 67}Ga- PhoF displayed not only a significant tumor uptake, but also rapid blood clearance (T{sub 1/2} {sub fast} {sub phase}= 3.7 min. and T{sub 1/2} {sub slow} {sub phase}= 127.2 min.) and low accumulations in non target tissues, resulting in high target-to-non target ratios. Scintigraphic images of {sup 67}Ga- PhoF in nude mice bearing U87-MG tumor showed a significant activity in tumor ({approx} 7% of total activity) and tumor-to-normal tissue ratio was more than 10-fold higher depending on the organ. Our results suggest that {sup 67}Ga-PhoF possess indispensable characteristics for a good radiopharmaceutical for brain tumor diagnosis. (author)

  9. Synthesis and in vivo evaluation of novel radiotracers for the in vivo imaging of the norepinephrine transporter

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Alan A. E-mail: aaw@camhpet.on.ca; Patrick Johnson, David; Mozley, David; Hussey, Doug; Ginovart, Nathalie; Nobrega, Jose; Garcia, Armando; Meyer, Jeffery; Houle, Sylvain

    2003-02-01

    The (R,R) and (S,S) enantiomers of 2-[(2-methoxyphenoxy)phenylmethyl]morpholine (MeNER) have been radiolabelled with carbon-11 in good yield and at high specific activity. These radiotracers are close analogues of reboxetine, a potent and selective ligand for the norepinephrine transporter (NET). They were examined as potential ligands for imaging NET in vivo by positron emission tomography (PET). The in vivo brain distribution of both [{sup 11}C]-labeled enantiomers were evaluated in rats. Following tail-vein injection of the (R,R)-enantiomer regional brain uptake and washout of radioactivity was homogeneous at all time points examined (5-60 min). In contrast, administration of the (S,S)-enantiomer produced a heterogeneous distribution of radioactivity in brain with highest uptake in the hypothalamus, a NET rich region, and lowest uptake in the striatum, a brain region devoid of NET. Hypothalamus to striatum ratios of 2.5 to one were achieved at 60 min post injection of (S,S)-[{sup 11}C]-MeNER. Pre-injection of the norepinephrine reuptake inhibitors, reboxetine or desipramine, reduced hypothalamus to striatum ratios to near unity while reuptake inhibitors of dopamine and serotonin had no significant effect on binding. In vitro autoradiography studies (rat brain slices) with (S,S)-[{sup 11}C]-MeNER produced a regional distribution pattern that was consistent with the reported distribution of NET. (S,S)-[{sup 11}C]-MeNER has the potential to be the first successful PET ligand to image NET.

  10. Development of gamma emitting receptor binding radiotracers for imaging the brain and pancreas. Final technical progress report, March 1, 1988--May 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-01-01

    This document give paragraph synopses of results in research on brain and pancreas imaging, using radiotracers. General catagories of research included chemistry, pharmacology, imaging physics, and kinetic modeling. A list of publications is included

  11. Semi-automated lab-on-a-chip for dispensing GA-68 radiotracers

    Energy Technology Data Exchange (ETDEWEB)

    Weinberg, Irving [Weinberg Medical Physics LLC, Bethesda, MD (United States)

    2014-03-12

    We solved a technical problem that is hindering American progress in molecular medicine, and restricting US citizens from receiving optimal diagnostic care. Specifically, the project deals with a mother/daughter generator of positron-emitting radiotracers (Ge-68/Ga-68). These generator systems are approved in Europe but cannot be used in the USA, because of safety issues related to possible breakthrough of long-lived Ge-68 (mother) atoms. Europeans have demonstrated abilities of Ga-68-labeled radiotracers to image cancer foci with high sensitivity and specificity, and to use such methods to effectively plan therapy.The USA Food and Drug Administration (FDA) and Nuclear Regulatory Commission (NRC) have taken the position that every patient administration of Ga-68 should be preceded by an assay demonstrated that Ge-68 breakthrough is within acceptable limits. Breakthrough of parent elements is a sensitive subject at the FDA, as evidenced by the recent recall of Rb-82 generators due to inadvertent administrations of Sr-82. Commercially, there is no acceptable rapid method for assaying breakthrough of Ge-68 prior to each human administration. The gamma emissions of daughter Ga-68 have higher energies than the parent Ge-68, so that the shielding assays typically employed for Mo-99/Tc-99m generators cannot be applied to Ga-68 generators. The half-life of Ga-68 is 68 minutes, so that the standard 10-half-life delay (used to assess breakthrough in Sr-82/Rb-82 generators) cannot be applied to Ga-68 generators. As a result of the aforementioned regulatory requirements, Ga-68 generators are sold in the USA for animal use only.The American clinical community’s inability to utilize Ga-68 generators impairs abilities to treat patients domestically, and puts the USA at a disadvantage in developing exportable products. The proposed DOE project aimed to take advantage of recent technological advances developed for lab-on-a-chip (LOC) applications. Based on our experiences

  12. Simpler and More Accurate: Weighing the Mercury in Electrolytic Cells by Radiotracer Dilution Method

    Directory of Open Access Journals (Sweden)

    Sugiharto

    2010-08-01

    Full Text Available Weight of mercury in electrolytic cell of soda industry is usually measured gravimetrically, which is typical labor work in character. Error sources of the gravimetric method might have come from the fact that some mercury’s are usually trapped in the cell due to complicated structure of electrolytic cell. This cause unknown errors. In addition, formation of amalgam at the cathode may cause a further uncertainty in the measurement. Total error from gravimetric method is 4% on average. Radiotracer dilution method provides advantages either for simplification of procedure and reduction of measurement error. In this experiment radioisotope mercury 203Hg, which was prepared in nuclear reactor was used to examine 13 of 14 electrolytic cells of soda plant. Each electrolytic cell was designed containing approximately 700 kg inactive mercury. Before injection, the radioisotope mercury was mixed with non radioisotope mercury in a bath to obtain a suitable injection aliquots and standard references. Calibration curve, which was derived from two stage dilution processes taken from standard references, was used to examine degree of mixing between radioisotope and non radioisotope mercury and it was also used in weight calculation of non radioisotope mercury in electrolytic cell. Injection was carried out simply by pouring the injection aliquots into the flowing mercury at the inlet side of the cell. Mercury samples from the cells were extracted at regular time intervals and filled into vials for counting. This was done for the primary conformation of the completeness of mixing of the tracer with the non radioisotope mercury in each cell. When complete mixing is achieved, the unknown quantity of mercury in each cell was calculated based on mass balance principle. From the calculation the weight of mercury in each electrolytic cell was not the same and maximum error of measurement obtained from this method is 2.48 %. Compared to gravimetrically error

  13. Abnormal gastrointestinal accumulation of radiotracer by gastric bleeding during {sup 99m}Tc-MDP bone scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Kyung A.; Lee, Sang Woo; Lee, Jae Tae; Lee, Kyu Bo [College of Medicine, Kyungpook National Univ., Taegu (Korea, Republic of)

    1998-06-01

    We present a case in which a patient with acute hemorrhagic gastritis demonstrated abnormal gastrointestinal accumulation of radiotracer during {sup 99m}Tc-methylene diphosphonate (MDP) skeletal scintigraphy. A hemorrhagic gastritis was subsequently demonstrated by endoscopy. The mechanism for the intestinal localization of {sup 99m}Tc-MDP in this patients is not clear, but we guess that the extravasated blood containing the radiopharmaceutical cannot recirculate and stays at the bleeding site, so we can see the intestinal activity.

  14. The synthesis and evaluation of N{sup 1}-(4-(2-[{sup 18}F]-fluoroethyl)phenyl)-N{sup 8}-hydroxyoctanediamide ([{sup 18}F]-FESAHA), A PET radiotracer designed for the delineation of histone deacetylase expression in cancer

    Energy Technology Data Exchange (ETDEWEB)

    Zeglis, Brian M.; Pillarsetty, NagaVaraKishore; Divilov, Vadim [Radiochemistry Service, Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021 (United States); Blasberg, Ronald A. [Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021 (United States); Lewis, Jason S., E-mail: lewisj2@mskcc.org [Radiochemistry Service, Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021 (United States); Program in Molecular Pharmacology and Chemistry, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10021 (United States)

    2011-07-15

    Introduction: Given the significant utility of suberoylanilide hydroxamic acid (SAHA) in chemotherapeutic protocols, a PET tracer that mimics the histone deacetylase (HDAC) inhibition of SAHA could be a valuable tool in the diagnosis, treatment planning and treatment monitoring of cancer. Here, we describe the synthesis, characterization and evaluation of N{sup 1}-(4-(2-[{sup 18}F]-fluoroethyl)phenyl)-N{sup 8}-hydroxyoctanediamide ([{sup 18}F]-FESAHA), a PET tracer designed for the delineation of HDAC expression in cancer. Methods: FESAHA was synthesized and biologically characterized in vivo and in vitro. [{sup 18}F]-FESAHA was then synthesized in high radiochemical purity, and the logP and serum stability of the radiotracer were determined. In vitro cellular uptake experiments and acute biodistribution and small-animal PET studies were performed with [{sup 18}F]-FESAHA in mice bearing LNCaP xenografts. Results: [{sup 18}F]-FESAHA was synthesized in high radiochemical purity via an innovative one-pot procedure. Enzymatic inhibition assays illustrated that FESAHA is a potent HDAC inhibitor, with IC{sub 50} values from 3 nM to 1.7 {mu}M against the 11 HDAC subtypes. Cell proliferation experiments revealed that the cytostatic properties of FESAHA very closely resemble those of SAHA in both LNCaP cells and PC-3 cells. Acute biodistribution and PET imaging experiments revealed tumor uptake of [{sup 18}F]-FESAHA and substantially higher values in the small intestine, kidneys, liver and bone. Conclusion: The significant non-tumor background uptake of [{sup 18}F]-FESAHA presents a substantial obstacle to the use of the radiotracer as an HDAC expression imaging agent. The study at hand, however, does present a number of lessons critical to both the synthesis of hydroxamic acid containing PET radiotracers and imaging agents aimed at delineating HDAC expression.

  15. Detailed spatio-temporal solids concentration profiling during batch settling of activated sludge using a radiotracer.

    Science.gov (United States)

    De Clercq, Jeriffa; Jacobs, Filip; Kinnear, David J; Nopens, Ingmar; Dierckx, Rudi A; Defrancq, Jacques; Vanrolleghem, Peter A

    2005-05-01

    In building and tuning good settling models for secondary clarifiers of wastewater treatment plants, there is a need for measured continuous solids concentration profiles during batch settling. Conventional measuring techniques have difficulties in recording this kind of data, either because they are invasive, or because of the low solids concentration and/or solids density of activated sludge. This paper investigates a novel non-invasive measurement technique borrowed from nuclear medicine, using a solids radiotracer and gamma cameras, to obtain solids concentration profiles during the batch settling of activated sludge, in a pilot-scale column with a height of 1m. The technique does not disturb the settling process, does not alter the settling characteristics, gives profiles every minute and every few millimeters, and is capable of measuring in a range of 0-25 g/l with high accuracy. Dynamic solids concentration profile measurements were performed for sludges of different wastewater treatment plants, and at different initial concentrations. The results show a quantitative representation of the settling process, and reveal hindered and compression settling.

  16. A study of a curious arithmetic function

    CERN Document Server

    Farhi, Bakir

    2010-01-01

    In this note, we study the arithmetic function $f : \\mathbb{Z}_+^* \\to \\mathbb{Q}_+^*$ defined by $f(2^k \\ell) = \\ell^{1 - k}$ ($\\forall k, \\ell \\in \\mathbb{N}$, $\\ell$ odd). We show several important properties about that function and then we use them to obtain some curious results involving the 2-adic valuation.

  17. Recent Studies in Functional Analytic Psychotherapy

    Science.gov (United States)

    Garcia, Rafael Ferro

    2008-01-01

    Functional Analytic Psychotherapy (FAP), based on the principles of radical behaviorism, emphasizes the impact of eventualities that occur during therapeutic sessions, the therapist-client interaction context, functional equivalence between environments, natural reinforcement and shaping by the therapist. This paper reviews recent studies of FAP…

  18. [{sup 11}C]d-threo-Methylphenidate, a new radiotracer for the dopamine transporter. Characterization in baboon and human brain

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Y.S.; Volkow, N.D.; Fowler, J.S. [Brookhaven National Laboratory, Upton, NY (United States)] [and others

    1995-05-01

    dl-threo Methylphenidate (MP, Ritalin) is a psychostimulant drug which binds to the dopamine transporter (DAT). We evaluated [{sup 11}C]d-threo-methylphenidate ([{sup 11}C]d-MP), the more active enantiomer, as a radiotracer for the DAT in baboons and human brain. Stereoselectivity, saturability and pharmacological specificity and reproducibility were examined. Stereoselectivity was examined in baboons by comparing [{sup 11C}]d-MP,[{sup 11}C]l-MP and [{sup 11}C]dl-MP. Unlabeled MP was used to assess the reversibility and saturability of the binding. GBR 12909,{beta}-(4-iodophenyl)tropane-2-carboxylic acid methyl ester ({beta}-CIT), tomoxetine and citalopram were used to assess the specificity of the binding. The ratios between the radioactivity in the striatum to that in cerebellum (ST/CB) were 3.3,2.2 and 1.1 for [{sup 11}C]d-MP,[{sup 11}C]dl-MP and [{sup 11}C]l-MP respectively. Most of the striatal binding of [{sup 11}C]d-threo-MP was displaced by injection of nonradioactive MP demonstrating reversibility. Pretreatment with MP (0.5 mg/kg), GBR12909 (1.5 mg/kg) or {beta}-CIT (0.3 mg/kg) reduced ST/CB by about 60% and the ratios of distribution volumes at the steady-state for the triatum to cerebellum (DV{sub st/}DV{sub cb}) by about 50%. Pretreatment with tomoxetine (3.0 mg/kg) or citalopram (2.0 mg/kg), inhibitors of the norepinephrine and serotonin transporter, had no effect. Studies of [{sup 11}C]d-MP in the human brain showed highest uptake in basal ganglia with a half clearance time of about 60 minutes. Repeated studies in 6 normal human subjects showed differences in DV{sub st/}DV{sub cb} between -7% and 8%. MP pretreatment decreased BG but no cortical or cerebellar binding and reduced Bmax/Kd by 91%.

  19. Novel (99m)Tc(III)-azide complexes [(99m)Tc(N3)(CDO)(CDOH)2B-R] (CDOH2=cyclohexanedione dioxime) as potential radiotracers for heart imaging.

    Science.gov (United States)

    Liu, Min; Zheng, Yumin; Avcibasi, Ugur; Liu, Shuang

    2016-11-01

    In this study, novel (99m)Tc(III)-azide complexes [(99m)Tc(N3)(CDO)(CDOH)2B-R] ((99m)Tc-ISboroxime-N3: R=IS; (99m)Tc-MPboroxime-N3: R=MP; (99m)Tc-PAboroxime-N3: R=PA; (99m)Tc-PYboroxime-N3: R=PY; and (99m)Tc-Uboroxime-N3: R=5U) were evaluated as heart imaging agents. Complexes [(99m)Tc(N3)(CDO)(CDOH)2B-R] (R=IS, MP, PA, PY and 5U) were prepared by ligand exchange between NaN3 and [(99m)TcCl(CDO)(CDOH)2B-R]. Biodistribution and imaging studies were carried out in Sprague-Dawley rats. Image quantification was performed to compare their initial heart uptake and myocardial retention. (99m)Tc-ISboroxime-N3, (99m)Tc-PYboroxime-N3 and (99m)Tc-Uboroxime-N3 were prepared with high RCP (93-98%) while the RCP of (99m)Tc-MPboroxime-N3 and (99m)Tc-PAboroxime-N3 was 80-85%. The myocardial retention curves of (99m)Tc-ISboroxime-N3, (99m)Tc-PYboroxime-N3 and (99m)Tc-Uboroxime-N3 were best fitted to the bi-exponential decay function. The half-time of the fast component was 1.6±0.4min for (99m)Tc-ISboroxime-N3, 0.7±0.1min for (99m)Tc-PYboroxime-N3 and 0.9±0.4min for (99m)Tc-Uboroxime-N3. The 2-min heart uptake from biodistribution studies followed the ranking order of (99m)Tc-ISboroxime-N3 (3.60±0.68%ID/g)>(99m)Tc-PYboroxime-N3 (2.35±0.37%ID/g)≫(99m)Tc-Uboroxime-N3 (1.29±0.06%ID/g). (99m)Tc-ISboroxime-N3 had the highest 2-min heart uptake among (99m)Tc radiotracers revaluated in SD rats. High quality SPECT images were obtained with the right and left ventricular walls being clearly delineated. The best image acquisition window was 0-5min for (99m)Tc-ISboroxime-N3. Both azide coligand and boronate caps had significant impact on the heart uptake and myocardial retention of complexes [(99m)Tc(N3)(CDO)(CDOH)2B-R]. Among the radiotracers evaluated in SD rats, (99m)Tc-ISboroxime-N3 has the highest initial heart uptake with the heart retention comparable to that of (99m)Tc-Teboroxime. (99m)Tc-ISboroxime-N3 is a promising alternative to (99m)Tc-Teboroxime for SPECT MPI. Copyright

  20. New perspectives of studying gastrointestinal muscle function

    Institute of Scientific and Technical Information of China (English)

    Hans Gregersen; Donghua Liao

    2006-01-01

    The motor function of the gastrointestinal tract has primarily been studied using manometry and radiography,though more indirect tests have also been applied. Manometry and radiography do not provide detailed information about the muscle properties as can be assessed from studies of muscle properties in muscle strips in vitro. In recent years a technique based on impedance planimetric mEasurement of pressure-cross-sectional area relations in a distending bag has proven to provide more detailed information about the muscle function in vivo. This review shows examples of new muscle function analysis such as length-tension diagrams, forcevelocity curves and preload-afterload diagrams.

  1. Small Molecule Receptor Ligands for PET Studies of the Central Nervous System-Focus on G Protein Coupled Receptors.

    Science.gov (United States)

    Mach, Robert H

    2017-09-01

    G protein-coupled receptors (GPRCs) are a class of proteins that are expressed in high abundance and are responsible for numerous signal transduction pathways in the central nervous system. Consequently, alterations in GPRC function have been associated with a wide variety of neurologic and neuropsychiatric disorders. The development of PET probes for imaging GPRCs has served as a major emphasis of PET radiotracer development and PET imaging studies over the past 30 years. In this review, a basic description of the biology of G proteins and GPRCs is provided. This includes recent evidence of the existence of dimeric and multimeric species of GPRCs that have been termed "receptor mosaics," with an emphasis on the different GPRCs that form complexes with the dopamine D2 receptor. An overview of the different PET radiotracers for imaging the component GPRC within these different multimeric complexes of the D2 receptor is also provided. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Discovery of a fluorinated 4-oxo-quinoline derivative as a potential positron emission tomography radiotracer for imaging cannabinoid receptor type 2.

    Science.gov (United States)

    Slavik, Roger; Müller Herde, Adrienne; Haider, Ahmed; Krämer, Stefanie D; Weber, Markus; Schibli, Roger; Ametamey, Simon M; Mu, Linjing

    2016-09-01

    The cannabinoid receptor type 2 (CB2) is part of the endocannabinoid system and has gained growing attention in recent years because of its important role in neuroinflammatory/neurodegenerative diseases. Recently, we reported on a carbon-11 labeled 4-oxo-quinoline derivative, designated RS-016, as a promising radiotracer for imaging CB2 using PET. In this study, three novel fluorinated analogs of RS-016 were designed, synthesized, and pharmacologically evaluated. The results of our efforts led to the identification of N-(1-adamantyl)-1-(2-(2-fluoroethoxy)ethyl)-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxamide (RS-126) as the most potent candidate for evaluation as a CB2 PET ligand. [(18) F]RS-126 was obtained in ≥ 99% radiochemical purity with an average specific radioactivity of 98 GBq/μmol at the end of the radiosynthesis. [(18) F]RS-126 showed a logD7.4 value of 1.99 and is stable in vitro in rat and human plasma over 120 min, whereas 55% intact parent compound was found in vivo in rat blood plasma at 10 min post injection. In vitro autoradiographic studies with CB2-positive rat spleen tissue revealed high and blockable binding which was confirmed in in vivo displacement experiments with rats by dynamic PET imaging. Ex vivo biodistribution studies confirmed accumulation of [(18) F]RS-126 in rat spleen with a specificity of 79% under blocking conditions. The moderate elevated CB2 levels in LPS-treated mice brain did not permit the detection of CB2 by [(18) F]RS-126 using PET imaging. In summary, [(18) F]RS-126 demonstrated high specificity toward CB2 receptor in vitro and in vivo and is a promising radioligand for imaging CB2 receptor expression. Cannabinoid receptor type 2 (CB2) is an interesting target for PET imaging. Specific binding of [(18) F]RS-126 in CB2-positive spleen tissue (white arrow head) was confirmed in in vivo displacement experiments with rats. Time activity curve of [(18) F]RS-126 in the spleen after the addition of GW405833 (CB2

  3. Improved Estrogen Receptor Assessment by PET Using the Novel Radiotracer 4FMFES in ER+ Breast Cancer Patients: an Ongoing Phase II Clinical Trial.

    Science.gov (United States)

    Paquette, Michel; Lavallée, Éric; Phoenix, Serge; Ouellet, René; Senta, Helena; van Lier, Johan E; Guérin, Brigitte; Lecomte, Roger; Turcotte, Éric E

    2017-08-10

    Following encouraging preclinical and human dosimetry results for the novel estrogen receptor (ER) positron emission tomography (PET) radiotracer 4-fluoro-11β-methoxy-16α-[(18)F]fluoroestradiol (4FMFES), a phase II clinical trial was initiated to compare the PET imaging diagnostic potential of 4FMFES to 16α-[(18)F]fluoroestradiol (FES) in ER positive (ER+) breast cancer patients. Methods: Patients diagnosed with ER+ breast cancer (n = 31) were recruited for this study, including six patients that undertook mastectomy and/or axillary node dissection. For each patient, FES- and 4FMFES-PET/CT scans were done sequentially (within a week) and in random order. One hour following injection of either radiotracer, a head-to-thigh static scan with 2 minutes acquisition per bed position was obtained. Blood samples were taken at different times following injection to assess each tracer metabolism by reverse-phase thin-layer chromatography (TLC). The mean standardized uptake values (SUVMean) of non-specific tissues and the maximum SUV (SUVMax) of the tumor were evaluated for each detected lesion, and tumor-to-non-specific organs ratios were calculated. Results: Blood metabolite analysis 60 minutes after injection of the tracer showed a 2.5-fold increase in metabolic stability of 4FMFES over FES. While for most foci 4FMFES-PET scored similar SUVMax values as compared to FES-PET, tumor contrast improved substantially in all cases. Lower uptake was consistently observed in non-specific tissues for 4FMFES, notably a 4-fold decrease in blood pool activity as compared to FES. Consequently, image quality was considerably improved using 4FMFES, with lower overall background. As a result, 4FMFES successfully identified 9 more lesions than FES. Conclusion: This phase II study with ER+ breast cancer patients shows that 4FMFES-PET achieves lower non-specific signal and better tumor contrast than FES-PET resulting in improved diagnostic confidence and lower false negative diagnoses

  4. Pancreatic Ductal Adenocarcinoma With High Radiotracer Uptake in 68Ga-Prostate-Specific Membrane Antigen PET/CT.

    Science.gov (United States)

    Sahbai, Samine; Rieping, Petra; Pfannenberg, Christina; la Fougére, Christian; Reimold, Matthias

    2017-09-01

    Prostate-specific membrane antigen imaging with PET/CT is increasingly used in prostate cancer and was shown to have a high diagnostic performance. We report a clinical case of a 67-year-old man with previous history of operated prostate cancer and increasing prostate-specific antigen blood level. Ga-HBED-CC prostate-specific membrane antigen PET/CT imaging was indicated for the assessment of local recurrence and lymph node metastases of prostate cancer. In addition, a soft tissue mass in the body of the pancreas with high radiotracer uptake was detected. Histopathology confirmed a pancreatic ductal adenocarcinoma.

  5. Density functional theory studies of etoricoxib

    Science.gov (United States)

    Sachdeva, Ritika; Kaur, Prabhjot; Singh, V. P.; Saini, G. S. S.

    2016-05-01

    Etoricoxib is a COX-2 selective inhibitor drug with molecular formula C18H15ClN2O2S. It is primarily used for the treatment of arthritis(rheumatoid, psoriatic, osteoarthritis), ankylosing spondylitis, gout and chronic low back pain. Theoretical studies of the molecule including geometry optimization and vibrational frequency calculations were carried out with the help of density functional theory calculations using 6-311++ g (d, p) basis set and B3LYP functional.

  6. Estimative of dilution factor for radioactive liquid effluents employing the H-3 and Cs-137 radiotracers present as pollutant; Estimativa do fator de diluicao para efluentes radioativos liquidos empregando os radiotracadores H-3 e Cs-137 presentes como poluentes

    Energy Technology Data Exchange (ETDEWEB)

    Nisti, Marcelo Bessa; Santos, Adir Janete Godoy dos, E-mail: mbnisti@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    It was estimated the dilution factor for liquid effluents at the discharge points of the IPEN, Sao Paulo, Brazil, employing as radiotracers the radioisotope routinely liberated for the sewage of 'Cidade Universitaria Armando de Salles Oliveira' - CUASO {sup 3}H and {sup 137}Cs, not generating either monetary or environmental cost associated to the estimation. The {sup 137}Cs was determined by gamma spectrometry and the {sup 3}H was determined liquid phase scintillation. The results showed that the dilution factor varied according to the employed radiotracer in a crescent order of {sup 3}H and {sup 137}Cs according to the characteristics of each element. The average of dilution factors obtained at the first and second liberation day were 4.3 and 7.4 respectively for the {sup 3}H and 6.2 and 13.9 for the {sup 137}Cs. The ratio of dilution factors of calculated {sup 3}H and {sup 137}Cs were coherent with the ratio verified at the twelve hydrometers distributed by the IPEN campus. The dilution factors were estimated in operational and laboratory study, in a single controlled discharge of the TR1 tank

  7. Functional studies on the phosphatidychloride transfer protein

    NARCIS (Netherlands)

    Brouwer, A.P.M. de

    2002-01-01

    The phosphatidylcholine transfer protein (PC-TP) has been studied for over 30 years now. Despite extensive research concerning the biochemical, biophysical and structural properties of PC-TP, the function of this protein is still elusive. We have studied in vitro the folding and the mechanism of PC

  8. Sulfur and Iron Cycling in a Coastal Sediment - Radiotracer Studies and Seasonal Dynamics

    DEFF Research Database (Denmark)

    MOESLUND, L.; THAMDRUP, B.; JØRGENSEN, BB

    1994-01-01

    , sulfidic zone, measured rates appeared to be correct. Sulfate reduction followed the seasonal variation in temperature with maximum activity at 1-2 cm depth in late summer. In spite of its rapid production, free H2S was detectable in the porewater only below the depth of free Fe2+ at 6-7 cm throughout...

  9. Measurements of liquid phase residence time distributions in a pilot-scale continuous leaching reactor using radiotracer technique.

    Science.gov (United States)

    Pant, H J; Sharma, V K; Shenoy, K T; Sreenivas, T

    2015-03-01

    An alkaline based continuous leaching process is commonly used for extraction of uranium from uranium ore. The reactor in which the leaching process is carried out is called a continuous leaching reactor (CLR) and is expected to behave as a continuously stirred tank reactor (CSTR) for the liquid phase. A pilot-scale CLR used in a Technology Demonstration Pilot Plant (TDPP) was designed, installed and operated; and thus needed to be tested for its hydrodynamic behavior. A radiotracer investigation was carried out in the CLR for measurement of residence time distribution (RTD) of liquid phase with specific objectives to characterize the flow behavior of the reactor and validate its design. Bromine-82 as ammonium bromide was used as a radiotracer and about 40-60MBq activity was used in each run. The measured RTD curves were treated and mean residence times were determined and simulated using a tanks-in-series model. The result of simulation indicated no flow abnormality and the reactor behaved as an ideal CSTR for the range of the operating conditions used in the investigation.

  10. Synthesis, radioiodination and in vivo screening of novel potent iodinated and fluorinated radiotracers as melanoma imaging and therapeutic probes.

    Science.gov (United States)

    Maisonial, Aurélie; Billaud, Emilie M F; Besse, Sophie; Rbah-Vidal, Latifa; Papon, Janine; Audin, Laurent; Bayle, Martine; Galmier, Marie-Josèphe; Tarrit, Sébastien; Borel, Michèle; Askienazy, Serge; Madelmont, Jean-Claude; Moins, Nicole; Auzeloux, Philippe; Miot-Noirault, Elisabeth; Chezal, Jean-Michel

    2013-05-01

    In order to develop new iodinated and fluorinated matched-pair radiotracers for Single-Photon Emission Computed Tomography (SPECT)/Positron Emission Tomography (PET) imaging and targeted radionuclide therapy of melanoma, we successfully synthesized and radiolabelled with iodine-125 seven new derivatives, starting from our previously described lead structure 3. The relevance of these radiotracers for gamma scintigraphic imaging of melanoma in rodent was assessed. The tumoural radioactivity uptake was most often high and specific even at early time points (12.1-18.3% ID/g at 3 h p.i. for [(125)I]39-42) and a fast clearance from the non-target organs was observed. Also, calculated effective doses that could be delivered to tumours when using corresponding [(131)I]-labelled analogues were generally higher than 100 cGy/MBq injected (98.9-150.5 cGy/MBq for [(131)I]39-42). These results make compounds 39-42 suitable candidates for (i) PET imaging of melanoma after labelling with fluorine-18 and (ii) targeted radionuclide therapy of disseminated melanoma after labelling with iodine-131.

  11. Affinity of (nat/68)Ga-Labelled Curcumin and Curcuminoid Complexes for β-Amyloid Plaques: Towards the Development of New Metal-Curcumin Based Radiotracers.

    Science.gov (United States)

    Rubagotti, Sara; Croci, Stefania; Ferrari, Erika; Iori, Michele; Capponi, Pier C; Lorenzini, Luca; Calzà, Laura; Versari, Annibale; Asti, Mattia

    2016-09-06

    Curcumin derivatives labelled with fluorine-18 or technetium-99m have recently shown their potential as diagnostic tools for Alzheimer's disease. Nevertheless, no study by exploiting the labelling with gallium-68 has been performed so far, in spite of its suitable properties (positron emitter, generator produced radionuclide). Herein, an evaluation of the affinity for synthetic β-amyloid fibrils and for amyloid plaques of three (nat/68)Ga-labelled curcumin analogues, namely curcumin curcumin (CUR), bis-dehydroxy-curcumin (bDHC) and diacetyl-curcumin (DAC), was performed. Affinity and specificity were tested in vitro on amyloid synthetic fibrils by using gallium-68 labelled compounds. Post-mortem brain cryosections from Tg2576 mice were used for the ex vivo visualization of amyloid plaques. The affinity of (68)Ga(CUR)₂⁺, (68)Ga(DAC)₂⁺, and (68)Ga(bDHC)₂⁺ for synthetic β-amyloid fibrils was moderate and their uptake could be observed in vitro. On the other hand, amyloid plaques could not be visualized on brain sections of Tg2576 mice after injection, probably due to the low stability of the complexes in vivo and of a hampered passage through the blood-brain barrier. Like curcumin, all (nat/68)Ga-curcuminoid complexes maintain a high affinity for β-amyloid plaques. However, structural modifications are still needed to improve their applicability as radiotracers in vivo.

  12. Functional magnetic resonance imaging studies of language.

    Science.gov (United States)

    Small, Steven L; Burton, Martha W

    2002-11-01

    Functional neuroimaging of language builds on almost 150 years of study in neurology, psychology, linguistics, anatomy, and physiology. In recent years, there has been an explosion of research using functional imaging technology, especially positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), to understand the relationship between brain mechanisms and language processing. These methods combine high-resolution anatomic images with measures of language-specific brain activity to reveal neural correlates of language processing. This article reviews some of what has been learned about the neuroanatomy of language from these imaging techniques. We first discuss the normal case, organizing the presentation according to the levels of language, encompassing words (lexicon), sound structure (phonemes), and sentences (syntax and semantics). Next, we delve into some unusual language processing circumstances, including second languages and sign languages. Finally, we discuss abnormal language processing, including developmental and acquired dyslexia and aphasia.

  13. Pulmonary function studies in Gujarati subjects.

    Science.gov (United States)

    Rao, N M; Mavlankar, M G; Kulkarni, P K; Kashyap, S K

    1992-01-01

    In this study a multiple regression equation for prediction of ventilatory pulmonary function tests (FVC, FEV1%, FEF25-75% and PEFR) is developed in average healthy non-smoker male and female Gujarati subjects. The average adult female values showed a reduction varying from 21.0 to 29.0% compared to adult male subjects. There is a deviation of the present study values from other studies in Indian subjects and values from European studies are higher than the present values. This study demonstrated that the present regression equation is the most ideal and appropriate for prediction of pulmonary function values in Gujarati subjects either for assessing physical fitness in normal subjects or for determining the pattern of ventilatory impairment in respiratory disease patients. The pulmonary function values assessed by substituting the average age, height and weight of females in male regression equation revealed lower values in females ranging from 14.0 to 19.0% attributable only due to difference in sex.

  14. A generally adoptable radiotracing method for tracking carbon nanotubes in animals

    Energy Technology Data Exchange (ETDEWEB)

    Deng Xiaoyong; Yang Shengtao; Nie Haiyu; Wang Haifang; Liu Yuanfang [Beijing National Laboratory for Molecular Sciences, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China)], E-mail: haifangw@pku.edu.cn

    2008-02-20

    Carbon nanotube (CNT) mediated drug delivery systems have currently aroused a great deal of interest. Such delivery systems for drugs, proteins and genes have been preliminarily studied using cellular and animal models. For the further study of the pharmacokinetics and related biological behaviours of CNTs in vivo, a fast and convenient tracing method is particularly demanded. In this paper, we developed a generally adoptable tracing method for the biodistribution study of functionalized CNTs in vivo. Taurine covalently functionalized multi-walled carbon nanotubes (tau-MWNTs) and Tween-80 wrapped MWNTs (Tween-MWNTs) were labelled with {sup 125}I, and then their distribution in mice was determined. It is interesting that Tween-80 can reduce the RES uptake of MWNTs remarkably. The resulting distribution of {sup 125}I-tau-MWNTs was very consistent with that using {sup 14}C-taurine-MWNTs as the CNTs tracer, which means the easy {sup 125}I labelling method is reliable and effective.

  15. Tissue biodistribution and blood clearance rates of intravenously administered carbon nanotube radiotracers

    Science.gov (United States)

    Singh, Ravi; Pantarotto, Davide; Lacerda, Lara; Pastorin, Giorgia; Klumpp, Cédric; Prato, Maurizio; Bianco, Alberto; Kostarelos, Kostas

    2006-02-01

    Carbon nanotubes (CNT) are intensively being developed for biomedical applications including drug and gene delivery. Although all possible clinical applications will require compatibility of CNT with the biological milieu, their in vivo capabilities and limitations have not yet been explored. In this work, water-soluble, single-walled CNT (SWNT) have been functionalized with the chelating molecule diethylentriaminepentaacetic (DTPA) and labeled with indium (111In) for imaging purposes. Intravenous (i.v.) administration of these functionalized SWNT (f-SWNT) followed by radioactivity tracing using gamma scintigraphy indicated that f-SWNT are not retained in any of the reticuloendothelial system organs (liver or spleen) and are rapidly cleared from systemic blood circulation through the renal excretion route. The observed rapid blood clearance and half-life (3 h) of f-SWNT has major implications for all potential clinical uses of CNT. Moreover, urine excretion studies using both f-SWNT and functionalized multiwalled CNT followed by electron microscopy analysis of urine samples revealed that both types of nanotubes were excreted as intact nanotubes. This work describes the pharmacokinetic parameters of i.v. administered functionalized CNT relevant for various therapeutic and diagnostic applications. nanomedicine | blood circulation half-life | drug delivery | pharmacokinetics | nanotoxicology

  16. DOE Final Technical Report (2009-2016): "Research Projects for Interrogations of Biological Systems: Training for the Development of Novel Radiotracers"

    Energy Technology Data Exchange (ETDEWEB)

    Jurisson, Silvia [University of Missouri-Columbia; Lever, Susan [University of Missouri-Columbia; Robertson, J. David [University of Missouri-Columbia

    2016-10-04

    This is the final technical report for DOE grant DE-SC-0002040, which was entitled "Research Projects for Interrogations of Biological Systems: Training for the Development of Novel Radiotracers". Included are the students and postdoctoral fellows trained, the publications, dissertations, presentations, and other deliverables for this project.

  17. Radiosynthesis and radiopharmacological evaluation of [N-methyl-{sup 11}C]Org 34850 as a glucocorticoid receptor (GR)-binding radiotracer

    Energy Technology Data Exchange (ETDEWEB)

    Wuest, Frank [Institut fuer Radiopharmazie, Forschungszentrum Dresden-Rossendorf e.V., POB 51 01 19, D-01314 Dresden (Germany); Department of Oncologic Imaging, Cross Cancer Institute, University of Alberta, Edmonton, Alberta, Canada T6G 1Z2 (Canada)], E-mail: frankwue@cancerboard.ab.ca; Kniess, Torsten [Institut fuer Radiopharmazie, Forschungszentrum Dresden-Rossendorf e.V., POB 51 01 19, D-01314 Dresden (Germany); Henry, Brian; Peeters, Bernardus W.M.M.; Wiegerinck, Peter H.G. [Schering-Plough, PO Box 20, 5340 BH Oss (Netherlands); Pietzsch, Jens; Bergmann, Ralf [Institut fuer Radiopharmazie, Forschungszentrum Dresden-Rossendorf e.V., POB 51 01 19, D-01314 Dresden (Germany)

    2009-02-15

    The radiosynthesis of [N-methyl-{sup 11}C]Org 34850 as a potential brain glucocorticoid receptor (GR)-binding radiotracer is described. The radiosynthesis was accomplished via N-methylation of the corresponding desmethyl precursor with [{sup 11}C]methyl triflate in a remotely controlled synthesis module to give the desired compound in a radiochemical yield of 23{+-}5% (decay-corrected, based upon [{sup 11}C]CO{sub 2}) at a specific activity of 47{+-}12 GBq/{mu}mol (n=15) at the end-of-synthesis (EOS). The radiochemical purity after semi-preparative HPLC purification exceeded 95%. The total synthesis time was 35-40 min after end-of-bombardment (EOB). The radiotracer is rapidly metabolized in rat plasma leading to the formation of two more hydrophilic metabolites as the major metabolites. Radiopharmacological evaluation involving biodistribution and small animal PET imaging in normal Wistar rats showed that the compound [N-methyl-{sup 11}C]Org 34850 is not able to sufficiently penetrate the blood-brain barrier. Therefore, compound [N-methyl-{sup 11}C]Org 34850 seems not to be a suitable PET radiotracer for imaging rat brain GRs. However, involvement of Pgp or species differences requires further clarification to establish whether the radiotracer [N-methyl-{sup 11}C]Org 34850 may still represent a suitable candidate for imaging GRs in humans.

  18. In vivo evaluation of [{sup 11}C]-3-[2-[(3-methoxyphenylamino)carbonyl]ethenyl]-4,6-dichloroindole- 2-carboxylic acid ([{sup 11}C]3MPICA) as a PET radiotracer for the glycine site of the NMDA ion channel

    Energy Technology Data Exchange (ETDEWEB)

    Waterhouse, Rikki N. E-mail: rnw7@columbia.edu; Sultana, Abida; Laruelle, M

    2002-11-01

    Alterations in normal NMDA receptor composition, densities and function have been implicated in the pathophysiology of certain neurological and neuropsychiatric disorders such as Parkinson's Disease, Huntington's Chorea, schizophrenia, alcoholism and stroke. In our first effort to provide PET ligands for the NMDA/glycine site, we reported the synthesis of a novel high affinity glycine site ligand, 3-[2-[(3-methoxyphenylamino)carbonyl]ethenyl]-4,6-dichloroindole-2 -carboxylic acid ((3MPICA), Ki=4.8{+-}0.9 nM) and the corresponding carbon-11 labeled PET ligand, [{sup 11}C]3MPICA. We report here the in vivo evaluation of [{sup 11}C]3MPICA in rats. Biodistribution analysis revealed that [{sup 11}C]3MPICA exhibited low degree of brain penetration and high blood concentration. The average uptake at two minutes was highest in the cerebellum (0.19{+-}0.04 %ID/g) and thalamus (0.18{+-}0.05 %ID/g) and lower in the hippocampus (0.13{+-}0.03) and frontal cortex (0.11{+-}0.04 %ID/g). The radioactivity cleared quickly from all brain regions examined. Administration of unlabeled 3MPICA (1 mg/kg, i.v.) revealed at 60 minutes a small general reduction in regional brain radioactivity concentrations in treated animals versus controls, however, the blood radioactivity concentration was also lowered, confounding the assessment of the degree of saturable binding. Warfarin co-administration (100 mg/kg, i.v.) significantly lowered blood activity at 5 minutes post-injection (-27%, P<0.01) but failed to significantly increase the brain uptake of the radiotracer. In view of these results, and especially considering the low brain penetration of this tracer, [{sup 11}C]3MPICA does not appear to be a promising PET radiotracer for in vivo use.

  19. Synthesis and in vivo Evaluation of Fluorine-18 and Iodine-123 Pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine Derivatives as PET and SPECT Radiotracers for Mapping A2A Receptors.

    Science.gov (United States)

    Vala, Christine; Morley, Thomas J; Zhang, Xuechun; Papin, Caroline; Tavares, Adriana Alexandre S; Lee, H Sharon; Constantinescu, Cristian; Barret, Olivier; Carroll, Vincent M; Baldwin, Ronald M; Tamagnan, Gilles D; Alagille, David

    2016-09-06

    Imaging agents that target adenosine type 2A (A2A ) receptors play an important role in evaluating new pharmaceuticals targeting these receptors, such as those currently being developed for the treatment of movement disorders like Parkinson's disease. They are also useful for monitoring progression and treatment efficacy by providing a noninvasive tool to map changes in A2A receptor density and function in neurodegenerative diseases. We previously described the successful evaluation of two A2A -specific radiotracers in both nonhuman primates and in subsequent human clinical trials: [(123) I]MNI-420 and [(18) F]MNI-444. Herein we describe the development of both of these radiotracers by selection from a series of A2A ligands, based on the pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine core of preladenant. Each of this series of 16 ligands was found to bind to recombinant human A2A receptor in the low nanomolar range, and of these 16, six were radiolabeled with either fluorine-18 or iodine-123 and evaluated in nonhuman primates. These initial in vivo results resulted in the identification of 7-(2-(4-(4-(2-[(18) F]fluoroethoxy)phenyl)piperazin-1-yl)ethyl)-2-(furan-2-yl)-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine ([(18) F]MNI-444) and 7-(2-(4-(2-fluoro-4-[(123) I]iodophenyl)piperazin-1-yl)ethyl)-2-(furan-2-yl)-7H-imidazo[1,2-c]pyrazolo[4,3-e]pyrimidin-5-amine ([(123) I]MNI-420) as PET and SPECT radiopharmaceuticals for mapping A2A receptors in brain.

  20. The role of electromagnetic separators in the production of radiotracers for bio-medical research and nuclear medical application

    Science.gov (United States)

    Beyer, Gerd J.; Ruth, Thomas J.

    2003-05-01

    With the growing complexity of positron emission tomography/single photon emission computed tomography imaging and the new developments in systemic radionuclide therapy there is a growing need for radioisotope preparations with higher radiochemical and radionuclidic purity that has not been achievable before. Especially important for the new applications is the specific activity of the radiotracer. Conventional methods in medical isotope production have reached their technical limitations. The role of isotope separators is discussed with examples of typical production and characterization experiments conducted at the ISOLDE and TRIUMF facilities. These preliminary experiments indicate that isotope separators have a definite role to play in the future for the production of radioisotopes for biomedical research and medical application.

  1. The role of electromagnetic separators in the production of radiotracers for bio-medical research and nuclear medical application

    CERN Document Server

    Beyer, Gerd-Jürgen

    2003-01-01

    With the growing complexity of positron emission tomography/single photon emission computed tomography imaging and the new developments in systemic radionuclide therapy there is a growing need for radioisotope preparations with higher radiochemical and radionuclidic purity that has not been achievable before. Especially important for the new applications is the specific activity of the radiotracer. Conventional methods in medical isotope production have reached their technical limitations. The role of isotope separators is discussed with examples of typical production and characterization experiments conducted at the ISOLDE and TRIUMF facilities. These preliminary experiments indicate that isotope separators have a definite role to play in the future for the production of radioisotopes for biomedical research and medical application.

  2. Application of palladium-mediated (18F-fluorination to PET radiotracer development: overcoming hurdles to translation.

    Directory of Open Access Journals (Sweden)

    Adam S Kamlet

    Full Text Available New chemistry methods for the synthesis of radiolabeled small molecules have the potential to impact clinical positron emission tomography (PET imaging, if they can be successfully translated. However, progression of modern reactions from the stage of synthetic chemistry development to the preparation of radiotracer doses ready for use in human PET imaging is challenging and rare. Here we describe the process of and the successful translation of a modern palladium-mediated fluorination reaction to non-human primate (NHP baboon PET imaging-an important milestone on the path to human PET imaging. The method, which transforms [(18F]fluoride into an electrophilic fluorination reagent, provides access to aryl-(18F bonds that would be challenging to synthesize via conventional radiochemistry methods.

  3. Hybrid functional study of α-uranium

    Science.gov (United States)

    Kaur, Gurpreet; Chinnappan, Ravi; Panigrahi, B. K.

    2016-05-01

    We have used the hybrid density functionals to study the structural and electronic properties of alpha-U. The fraction of exact Hartree Folk exchange used is varied from 0.0 to 0.6. The equilibrium volume is found to be underestimated and bulk modulus overestimated with HSE as compared to both calculated by PBE and the experimental values. Electronic bands below the Fermi level are found to shift to lower energy with respect to PBE electronic bands which itself gives the bands shifted to lower energies as compared to UPS experiments.

  4. Functional MRI studies in disruptive behaviour disorders.

    Science.gov (United States)

    Bellani, M; Garzitto, M; Brambilla, P

    2012-03-01

    Aggressive or antisocial behaviours with violations of social rules are the main features of disruptive behaviour disorders (DBDs), which are developmental diseases and include conduct disorder and oppositional defiant disorder. In the last decade, several efforts have been made to shed light on the biological underpinnings of DBDs. In this context, the main findings of functional magnetic resonance imaging studies in DBD are reported here. There are indications of neural dysfunctions in response to affective stimuli, especially regarding medial and orbitofrontal prefrontal cortex and connected subcortical structures.

  5. Studying Functions of All Yeast Genes Simultaneously

    Science.gov (United States)

    Stolc, Viktor; Eason, Robert G.; Poumand, Nader; Herman, Zelek S.; Davis, Ronald W.; Anthony Kevin; Jejelowo, Olufisayo

    2006-01-01

    A method of studying the functions of all the genes of a given species of microorganism simultaneously has been developed in experiments on Saccharomyces cerevisiae (commonly known as baker's or brewer's yeast). It is already known that many yeast genes perform functions similar to those of corresponding human genes; therefore, by facilitating understanding of yeast genes, the method may ultimately also contribute to the knowledge needed to treat some diseases in humans. Because of the complexity of the method and the highly specialized nature of the underlying knowledge, it is possible to give only a brief and sketchy summary here. The method involves the use of unique synthetic deoxyribonucleic acid (DNA) sequences that are denoted as DNA bar codes because of their utility as molecular labels. The method also involves the disruption of gene functions through deletion of genes. Saccharomyces cerevisiae is a particularly powerful experimental system in that multiple deletion strains easily can be pooled for parallel growth assays. Individual deletion strains recently have been created for 5,918 open reading frames, representing nearly all of the estimated 6,000 genetic loci of Saccharomyces cerevisiae. Tagging of each deletion strain with one or two unique 20-nucleotide sequences enables identification of genes affected by specific growth conditions, without prior knowledge of gene functions. Hybridization of bar-code DNA to oligonucleotide arrays can be used to measure the growth rate of each strain over several cell-division generations. The growth rate thus measured serves as an index of the fitness of the strain.

  6. A functional neuroimaging study of motivation and executive function.

    Science.gov (United States)

    Taylor, Stephan F; Welsh, Robert C; Wager, Tor D; Phan, K Luan; Fitzgerald, Kate D; Gehring, William J

    2004-03-01

    Executive functions, such as working memory, must intersect with functions that determine value for the organism. Functional imaging work in humans and single-unit recordings in non-human primates provide evidence that PFC might integrate motivational context with working memory. With functional magnetic resonance imaging (fMRI), we addressed the question of motivation and working memory, using a trial-related design in an object-working memory task. The design permitted the analysis of BOLD signal at separate stages, corresponding to encoding, maintenance, and retrieval. Subjects were motivated by a financial incentive during the task, such that they could gain a high or a low reward. The two different levels of reward also entailed greater or lesser risk of losing money for incorrect responses. In the high, relative to the low, reward condition, subjects shifted response bias, and showed a trend to greater sensitivity. We found main effects in fMRI BOLD signal for reward, which overlapped with BOLD effects for maintenance of information, in the right superior frontal sulcus and bilateral intraparietal sulcus. We also found an interaction between reward and retrieval from working memory in the right dorsolateral prefrontal cortex. Main effects of load and reward occurred in adjacent regions of the ventrolateral PFC during retrieval. The data demonstrate that when subjects perform a simple working memory task, financial incentives motivate performance and interact with some of the same neural networks that process various stages of working memory. Areas of overlap and interaction may integrate information about value, or they may represent a general effect of motivation increasing neural effort.

  7. Functional analysis of variance for association studies.

    Directory of Open Access Journals (Sweden)

    Olga A Vsevolozhskaya

    Full Text Available While progress has been made in identifying common genetic variants associated with human diseases, for most of common complex diseases, the identified genetic variants only account for a small proportion of heritability. Challenges remain in finding additional unknown genetic variants predisposing to complex diseases. With the advance in next-generation sequencing technologies, sequencing studies have become commonplace in genetic research. The ongoing exome-sequencing and whole-genome-sequencing studies generate a massive amount of sequencing variants and allow researchers to comprehensively investigate their role in human diseases. The discovery of new disease-associated variants can be enhanced by utilizing powerful and computationally efficient statistical methods. In this paper, we propose a functional analysis of variance (FANOVA method for testing an association of sequence variants in a genomic region with a qualitative trait. The FANOVA has a number of advantages: (1 it tests for a joint effect of gene variants, including both common and rare; (2 it fully utilizes linkage disequilibrium and genetic position information; and (3 allows for either protective or risk-increasing causal variants. Through simulations, we show that FANOVA outperform two popularly used methods - SKAT and a previously proposed method based on functional linear models (FLM, - especially if a sample size of a study is small and/or sequence variants have low to moderate effects. We conduct an empirical study by applying three methods (FANOVA, SKAT and FLM to sequencing data from Dallas Heart Study. While SKAT and FLM respectively detected ANGPTL 4 and ANGPTL 3 associated with obesity, FANOVA was able to identify both genes associated with obesity.

  8. Reinvestigation of the synthesis and evaluation of [N-methyl-{sup 11}C]vorozole, a radiotracer targeting cytochrome P450 aromatase

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Won [Medical Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)], E-mail: swkim@bnl.gov; Biegon, Anat; Katsamanis, Zachary E. [Medical Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Ehrlich, Carolin W. [Johannes-Gutenberg Universitaet Mainz, Institut fuer Organische Chemie, Duesbergweg 10-14, Mainz (Germany); Hooker, Jacob M.; Shea, Colleen [Medical Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Muench, Lisa [National Institute on Alcoholism and Alcohol Abuse, Bethesda, MD (United States); Xu Youwen; King, Payton; Carter, Pauline; Alexoff, David L. [Medical Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Fowler, Joanna S. [Medical Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Department of Psychiatry, Mount Sinai School of Medicine, New York, NY (United States); Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY (United States)

    2009-04-15

    Introduction: We reinvestigated the synthesis of [N-methyl-{sup 11}C]vorozole, a radiotracer for aromatase, and discovered the presence of an N-methyl isomer which was not removed in the original purification method. Herein we report the preparation and positron emission tomography (PET) studies of pure [N-methyl-{sup 11}C]vorozole. Methods: Norvorozole was alkylated with [{sup 11}C]methyl iodide as previously described and also with unlabeled methyl iodide. A high-performance liquid chromatography (HPLC) method was developed to separate the regioisomers. Nuclear magnetic resonance (NMR) spectroscopy ({sup 13}C and 2D-nuclear Overhauser effect spectroscopy NMR) was used to identify and assign structures to the N-methylated products. Pure [N-methyl-{sup 11}C]vorozole and the contaminating isomer were compared by PET imaging in the baboon. Results: Methylation of norvorozole resulted in a mixture of isomers (1:1:1 ratio) based on new HPLC analysis using a pentafluorophenylpropyl bonded silica column, in which vorozole coeluted one of its isomers under the original HPLC conditions. Baseline separation of the three labeled isomers was achieved. The N-3 isomer was the contaminant of vorozole, thus correcting the original assignment of isomers. PET studies of pure [N-methyl-{sup 11}C]vorozole with and without the contaminating N-3 isomer revealed that only [N-methyl-{sup 11}C]vorozole binds to aromatase. [N-methyl-{sup 11}C]Vorozole accumulated in all brain regions with highest accumulation in the aromatase-rich amygdala and preoptic area. Accumulation was blocked with vorozole and letrozole consistent with reports of some level of aromatase in many brain regions. Conclusions: The discovery of a contaminating labeled isomer and the development of a method for isolating pure [N-methyl-{sup 11}C]vorozole combine to provide a new scientific tool for PET studies of the biology of aromatase and for drug research and development.

  9. Correction of an input function for errors introduced with automated blood sampling

    Energy Technology Data Exchange (ETDEWEB)

    Schlyer, D.J.; Dewey, S.L. [Brookhaven National Lab., Upton, NY (United States)

    1994-05-01

    Accurate kinetic modeling of PET data requires an precise arterial plasma input function. The use of automated blood sampling machines has greatly improved the accuracy but errors can be introduced by the dispersion of the radiotracer in the sampling tubing. This dispersion results from three effects. The first is the spreading of the radiotracer in the tube due to mass transfer. The second is due to the mechanical action of the peristaltic pump and can be determined experimentally from the width of a step function. The third is the adsorption of the radiotracer on the walls of the tubing during transport through the tube. This is a more insidious effect since the amount recovered from the end of the tube can be significantly different than that introduced into the tubing. We have measured the simple mass transport using [{sup 18}F]fluoride in water which we have shown to be quantitatively recovered with no interaction with the tubing walls. We have also carried out experiments with several radiotracers including [{sup 18}F]Haloperidol, [{sup 11}C]L-deprenyl, [{sup 18}]N-methylspiroperidol ([{sup 18}F]NMS) and [{sup 11}C]buprenorphine. In all cases there was some retention of the radiotracer by untreated silicone tubing. The amount retained in the tubing ranged from 6% for L-deprenyl to 30% for NMS. The retention of the radiotracer was essentially eliminated after pretreatment with the relevant unlabeled compound. For example less am 2% of the [{sup 18}F]NMS was retained in tubing treated with unlabelled NMS. Similar results were obtained with baboon plasma although the amount retained in the untreated tubing was less in all cases. From these results it is possible to apply a mathematical correction to the measured input function to account for mechanical dispersion and to apply a chemical passivation to the tubing to reduce the dispersion due to adsorption of the radiotracer on the tubing walls.

  10. Radiopharmacological evaluation of 6-deoxy-6-[{sup 18}F]fluoro-D-fructose as a radiotracer for PET imaging of GLUT5 in breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Wuest, Melinda, E-mail: mwuest@ualberta.c [Department of Oncology, University of Alberta - Cross Cancer Institute, Edmonton, AB-T6G 1Z2 (Canada); Trayner, Brendan J. [Department of Physiology, University of Alberta, Edmonton, AB-T6G 1Z2 (Canada); Grant, Tina N. [Department of Physiology, University of Alberta, Edmonton, AB-T6G 1Z2 (Canada); Department of Chemistry, University of Alberta, Edmonton, AB-T6G 1Z2 (Canada); Jans, Hans-Soenke; Mercer, John R.; Murray, David [Department of Oncology, University of Alberta - Cross Cancer Institute, Edmonton, AB-T6G 1Z2 (Canada); West, Frederick G. [Department of Chemistry, University of Alberta, Edmonton, AB-T6G 1Z2 (Canada); McEwan, Alexander J.B.; Wuest, Frank [Department of Oncology, University of Alberta - Cross Cancer Institute, Edmonton, AB-T6G 1Z2 (Canada); Cheeseman, Chris I. [Department of Physiology, University of Alberta, Edmonton, AB-T6G 1Z2 (Canada)

    2011-05-15

    Introduction: Several clinical studies have shown low or no expression of GLUT1 in breast cancer patients, which may account for the low clinical specificity and sensitivity of 2-deoxy-2-[{sup 18}F]fluoro-D-glucose ([{sup 18}F]FDG) used in positron emission tomography (PET). Therefore, it has been proposed that other tumor characteristics such as the high expression of GLUT2 and GLUT5 in many breast tumors could be used to develop alternative strategies to detect breast cancer. Here we have studied the in vitro and in vivo radiopharmacological profile of 6-deoxy-6-[{sup 18}F]fluoro-D-fructose (6-[{sup 18}F]FDF) as a potential PET radiotracer to image GLUT5 expression in breast cancers. Methods: Uptake of 6-[{sup 18}F]FDF was studied in murine EMT-6 and human MCF-7 breast cancer cells over 60 min and compared to [{sup 18}F]FDG. Biodistribution of 6-[{sup 18}F]FDF was determined in BALB/c mice. Tumor uptake was studied with dynamic small animal PET in EMT-6 tumor-bearing BALB/c mice and human xenograft MCF-7 tumor-bearing NIH-III mice in comparison to [{sup 18}F]FDG. 6-[{sup 18}F]FDF metabolism was investigated in mouse blood and urine. Results: 6-[{sup 18}F]FDF is taken up by EMT-6 and MCF-7 breast tumor cells independent of extracellular glucose levels but dependent on the extracellular concentration of fructose. After 60 min, 30{+-}4% (n=9) and 12{+-}1% (n=7) ID/mg protein 6-[{sup 18}F]FDF was found in EMT-6 and MCF-7 cells, respectively. 6-deoxy-6-fluoro-D-fructose had a 10-fold higher potency than fructose to inhibit 6-[{sup 18}F]FDF uptake into EMT-6 cells. Biodistribution in normal mice revealed radioactivity uptake in bone and brain. Radioactivity was accumulated in EMT-6 tumors reaching 3.65{+-}0.30% ID/g (n=3) at 5 min post injection and decreasing to 1.75{+-}0.03% ID/g (n=3) at 120 min post injection. Dynamic small animal PET showed significantly lower radioactivity uptake after 15 min post injection in MCF-7 tumors [standard uptake value (SUV)=0

  11. Radioiodine-labeled disulfide: a novel radiotracer for evaluation of tumor uptake

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, E. K.; Choi, Y. S.; Byun, S. S.; Baek, J. Y.; Lee, K. H.; Kim, S. E.; Choi, Y.; Kim, B. T. [Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2002-07-01

    Diallyl disulfide found in garlic has been known to inhibit the growth of various cancer cells. In this study, iodine-substituted disulfides were synthesized and their growth inhibitory effects on cancer cells (SUN C5 and MCF-7) were investigated. Dibenzyl disulfide was labeled with {sup 123}I/{sup 125}I for evaluation of tumor uptake. Halogen-substituted disulfides were synthesized using 2,2'-dithiobis(benzothiazole) and one equivalent each of the corresponding thiols. Growth inhibition studies were performed on cancer cells that were grown at 37 .deg. C for 48 hr prior to exposure to the disulfides. Radioiodine-labeled disulfide was prepared by halogen exchange reaction on the 4-bromodibenzyl disulfide in the presence of Na{sup 123}I/{sup 125}I and CuCl at 150 .deg. C for 60 min, followed by HPLC purification. Uptake of the radioactivity to SUN C5 cells was measured as a function of time, and inhibition studies were performed in the presence of either S-methyl methanethiosulfonate (MMTS) or diallyl disulfide. Disulfides were synthesized in the high yields (90%). Tumor growth inhibition studies by the 3 iododisulfides showed the inhibition (>95%) comparable to diallyl disulfide (100%). Cu(I)-assisted radioiodination gave 4-{sup 123}I/{sup 125}I-iododibenzyl disulfide in overall 30-40% radiochemical yield and with high specific activity. Cell uptake studies of the radiolabeled disulfide showed a time-dependent increase of the uptake (4-fold increase from 15 min to 2 hr). Both MMTS, a glutathione depleting agent, and diallyl disulfide reduced the uptake of the radioactivity in a dose-dependent manner. Inhibition studies suggest that uptake of disulfide to the tumor cells could be mediated by thiol-disulfide exchange. This study demonstrates that radioiodine-labeled dibenzyl disulfide may be useful for evaluation of tumor uptake.

  12. [{sup 123}I]-3-Iodcytisin as possible radiotracer for the imaging of nicotinic acetylcholine receptors using single photon emission computer tomography; [{sup 123}I]-3-Iodcytisin als moeglicher Radiotracer fuer die Darstellung der nikotinergen Acetylcholin Rezeptoren mittels Single-Photon-Emissions-Computertomographie

    Energy Technology Data Exchange (ETDEWEB)

    Paulik, Dagmar Julia

    2015-03-06

    For the synthesis of [{sup 123}I]-3-Iodcytisin as possible radiotracer for the imaging of nicotinic acetylcholine (nACh) receptors using SPECT two different technologies were used: the radio-iodination with iodogen and the radio-iodination with nitric acid. The latter one showed higher efficiency. The radiotracer will allow to detect degenerative processes and other nACh-depending diseases in the brain (Alzheimer, Parkinson) and to observe the progress. The autoradiography is aimed to the imaging of the nACh receptors in the brain bypassing the brain-blood barrier. The highest activity was measured in the thalamus of mice and rat brains.

  13. To see bruxism: a functional MRI study

    Science.gov (United States)

    2015-01-01

    Objective: Since the pathophysiology of bruxism is not clearly understood, there exists no possible treatment. The aim of this study is to investigate the cerebral activation differences between healthy subjects and patients with bruxism on behalf of possible aetiological factors. Methods: 12 healthy subjects and 12 patients with bruxism, a total of 24 right-handed female subjects (aged 20–27 years) were examined using functional MRI during tooth-clenching and resting tasks. Imaging was performed with 3.0-T MRI scanner with a 32-channel head coil. Differences in regional brain activity between patients with bruxism and healthy subjects (control group) were observed with BrainVoyager QX 2.8 (Brain Innovation, Maastricht, Netherlands) statistical data analysis program. Activation maps were created using the general linear model: single study and multistudy multisubject for statistical group analysis. This protocol was approved by the ethics committee of medical faculty of Kirikkale University, Turkey (02/04), based on the guidelines set forth in the Declaration of Helsinki. Results: The group analysis revealed a statistically significant increase in blood oxygenation level-dependent signal of three clusters in the control group (p < 0.005), which may indicate brain regions related with somatognosis, repetitive passive motion, proprioception and tactile perception. These areas coincide with Brodmann areas 7, 31, 39 and 40. It is conceivable that there are differences between healthy subjects and patients with bruxism. Conclusions: Our findings indicate that there was a decrease of cortical activation pattern in patients with bruxism in clenching tasks. This indicates decreased blood flow and activation in regional neuronal activity. Bruxism, as an oral motor disorder concerns dentistry, neurology and psychiatry. These results might improve the understanding and physiological handling of sleep bruxism. PMID:25806864

  14. Infrared Imaging System for Studying Brain Function

    Science.gov (United States)

    Mintz, Frederick; Mintz, Frederick; Gunapala, Sarath

    2007-01-01

    A proposed special-purpose infrared imaging system would be a compact, portable, less-expensive alternative to functional magnetic resonance imaging (fMRI) systems heretofore used to study brain function. Whereas a typical fMRI system fills a large room, and must be magnetically isolated, this system would fit into a bicycle helmet. The system would include an assembly that would be mounted inside the padding in a modified bicycle helmet or other suitable headgear. The assembly would include newly designed infrared photodetectors and data-acquisition circuits on integrated-circuit chips on low-thermal-conductivity supports in evacuated housings (see figure) arranged in multiple rows and columns that would define image coordinates. Each housing would be spring-loaded against the wearer s head. The chips would be cooled by a small Stirling Engine mounted contiguous to, but thermally isolated from, the portions of the assembly in thermal contact with the wearer s head. Flexible wires or cables for transmitting data from the aforementioned chips would be routed to an integrated, multichannel transmitter and thence through the top of the assembly to a patch antenna on the outside of the helmet. The multiple streams of data from the infrared-detector chips would be sent to a remote site, where they would be processed, by software, into a three-dimensional display of evoked potentials that would represent firing neuronal bundles and thereby indicate locations of neuronal activity associated with mental or physical activity. The 3D images will be analogous to current fMRI images. The data would also be made available, in real-time, for comparison with data in local or internationally accessible relational databases that already exist in universities and research centers. Hence, this system could be used in research on, and for the diagnosis of response from the wearer s brain to physiological, psychological, and environmental changes in real time. The images would also be

  15. Clinical Translation of an Albumin-Binding PET Radiotracer 68Ga-NEB

    Science.gov (United States)

    Zhang, Jingjing; Lang, Lixin; Zhu, Zhaohui; Li, Fang; Niu, Gang; Chen, Xiaoyuan

    2017-01-01

    Suitably labeled Evans blue dye has been successfully applied to evaluate cardiac function, vascular permeability, and lymphatic imaging in preclinical settings. This study documented the first-inhuman application of 68Ga-1,4,7-triazacyclononane-N,N′,N″-triacetic acid (NOTA)-NEB. Methods The NOTA-conjugated truncated form of Evans blue, NEB, was labeled with 68Ga and tested in BALB/C mice for dynamic PET and ex vivo biodistribution studies. Three healthy volunteers (2 men and 1 woman) underwent 90-min whole-body dynamic PET. The absorbed doses for major organs and whole body were calculated using OLINDA/EXM software. Eleven patients with focal hepatic lesions diagnosed by enhanced CT or MR imaging were subjected to whole-body PET/CT acquisitions at 30 min after intravenous injection of 111–148 MBq (3–4 mCi) of 68Ga-NEB. Results NEB dye was labeled with 68Ga (half-time, 68 min) with high yield and purity. After intravenous injection, 68Ga-NEB formed a complex with serum albumin, thus most of the radioactivity was retained in blood circulation. The tracer was demonstrated to be safe in both healthy volunteers and recruited patients without side effects or allergies. Among the 11 patients, hemangiomas showed much higher 68Ga-NEB signal intensity than the surrounding normal hepatic tissues, whereas no apparent difference between lesions and hepatic tissues was identified on 18F-FDG PET. All other focal hepatic lesions including hepatocellular carcinoma, hepatic cysts, and neuroendocrine tumor liver metastases showed negative 68Ga-NEB contrast to hepatic tissues. Conclusion As a blood-pool imaging agent, 68Ga-NEB is safe to use in the clinic, and our preliminary studies demonstrate the value of differentiating hepatic hemangioma from other benign or malignant focal hepatic lesions. Easy labeling with different positron emitters of various half-lives, excellent pharmacokinetics, and imaging quality warrant further clinical applications of NEB-based PET tracers

  16. Estimating Endogenous Dopamine Levels at D2 and D3 Receptors in Humans using the Agonist Radiotracer [11C]-(+)-PHNO

    Science.gov (United States)

    Caravaggio, Fernando; Nakajima, Shinichiro; Borlido, Carol; Remington, Gary; Gerretsen, Philip; Wilson, Alan; Houle, Sylvain; Menon, Mahesh; Mamo, David; Graff-Guerrero, Ariel

    2014-01-01

    Using positron emission tomography (PET) and an acute dopamine depletion challenge it is possible to estimate endogenous dopamine levels occupying dopamine D2/3 receptors (D2/3R) in humans in vivo. Our group has developed [11C]-(+)-PHNO, the first agonist radiotracer with preferential in vivo affinity for D3R. Thus, the use of [11C]-(+)-PHNO offers the novel possibility of (i) estimating in vivo endogenous dopamine levels at D2/3R using an agonist radiotracer, and (ii) estimating endogenous dopamine levels at D3R in extrastriatal regions such as the substantia nigra, hypothalamus, and ventral pallidum. Ten healthy participants underwent a [11C]-(+)-PHNO PET scan under baseline conditions and another under acute endogenous dopamine depletion achieved via oral administration of alpha-methyl-para-tyrosine (64 mg/kg). [11C]-(+)-PHNO binding was sensitive to acute dopamine depletion, allowing in vivo estimates of endogenous dopamine in D2R-rich regions (caudate and putamen), mixed D2/3R-rich regions (ventral striatum and globus pallidus), and extrastriatal D3R-rich regions (hypothalamus and ventral pallidum). Dopamine depletion decreased self-reported vigor, which was correlated with the reduction in dopamine levels in the globus pallidus. [11C]-(+)-PHNO is a suitable radiotracer for use in estimating endogenous dopamine levels at D2R and D3R in neuropsychiatric populations. PMID:24874713

  17. Estimating endogenous dopamine levels at D2 and D3 receptors in humans using the agonist radiotracer [(11)C]-(+)-PHNO.

    Science.gov (United States)

    Caravaggio, Fernando; Nakajima, Shinichiro; Borlido, Carol; Remington, Gary; Gerretsen, Philip; Wilson, Alan; Houle, Sylvain; Menon, Mahesh; Mamo, David; Graff-Guerrero, Ariel

    2014-11-01

    Using positron emission tomography (PET) and an acute dopamine depletion challenge it is possible to estimate endogenous dopamine levels occupying dopamine D2/3 receptors (D2/3R) in humans in vivo. Our group has developed [(11)C]-(+)-PHNO, the first agonist radiotracer with preferential in vivo affinity for D3R. Thus, the use of [(11)C]-(+)-PHNO offers the novel possibility of (i) estimating in vivo endogenous dopamine levels at D2/3R using an agonist radiotracer, and (ii) estimating endogenous dopamine levels at D3R in extrastriatal regions such as the substantia nigra, hypothalamus, and ventral pallidum. Ten healthy participants underwent a [(11)C]-(+)-PHNO PET scan under baseline conditions and another under acute endogenous dopamine depletion achieved via oral administration of alpha-methyl-para-tyrosine (64 mg/kg). [(11)C]-(+)-PHNO binding was sensitive to acute dopamine depletion, allowing in vivo estimates of endogenous dopamine in D2R-rich regions (caudate and putamen), mixed D2/3R-rich regions (ventral striatum and globus pallidus), and extrastriatal D3R-rich regions (hypothalamus and ventral pallidum). Dopamine depletion decreased self-reported vigor, which was correlated with the reduction in dopamine levels in the globus pallidus. [(11)C]-(+)-PHNO is a suitable radiotracer for use in estimating endogenous dopamine levels at D2R and D3R in neuropsychiatric populations.

  18. The Functions of Language: An Experimental Study

    Directory of Open Access Journals (Sweden)

    Gina Redhead

    2013-10-01

    Full Text Available We test between four separate hypotheses (social gossip, social contracts, mate advertising and factual information exchange for the function(s of language using a recall paradigm. Subjects recalled the social content of stories (irrespective of whether this concerned social behavior, defection or romantic events significantly better than they did ecological information. Recall rates were no better on ecological stories if they involved flamboyant language, suggesting that, if true, Miller's “Scheherazade effect” may not be independent of content. One interpretation of these results might be that language evolved as an all-purpose social tool, and perhaps acquired specialist functions (sexual advertising, contract formation, information exchange at a later date through conventional evolutionary windows of opportunity.

  19. Study on Pragmatic Functions of Irony

    Institute of Scientific and Technical Information of China (English)

    纪亚楠

    2014-01-01

    Irony is frequently used in our daily life. Traditionally, Irony is only considered as a figure of speech. Because of its im-portance and prevalence, irony has gotten a lot of attention over the last few years. In this paper, I concentrate on the pragmatic perspective of irony and try to find out the characteristics and functions of irony. In addition, the reasons of people choose to use irony in dairy life. At the beginning, I will introduce the basic definition and types of irony. Then I try to analyze the irony ac-cording to cooperative principles, politeness principle, irony principle, speech act theory of communication to explore the genera-tion and comprehension of irony. Moreover, I illustrate the pragmatic functions of irony with appropriate examples. Finally, the paper emphasizes the importance of irony and predicts future development of irony.

  20. Using CAVE technology for functional genomics studies.

    Science.gov (United States)

    Sensen, Christoph W

    2002-01-01

    We have established the first Java 3D-enabled CAVE (CAVE automated virtual environment). The Java application programming interface allows the complete separation of the program development from the program execution, opening new application domains for the CAVE technology. Programs can be developed on any Java-enabled computer platform, including Windows, Macintosh, and Linux workstations, and executed in the CAVE without modification. The introduction of Java, one of the major programming environments for bioinformatics, into the CAVE environment allows the rapid development applications for genome research, especially for the analysis of the spatial and temporal data that are being produced by functional genomics experiments. The CAVE technology will play a major role in the modeling of biological systems that is necessary to understand how these systems are organized and how they function.

  1. Studies on megakaryopoiesis and platelet function

    OpenAIRE

    Meinders, M.

    2015-01-01

    Platelets are blood circulating specialized subcellular fragments, which are produced by megakaryocytes. Platelets are essential for hemostasis and wound healing but also play a role in non-hemostatic processes such as the immune response or cancer metastasis. Considering the immediate precursors of platelets, normal megakaryocyte development is essential for normal platelet function. Although much is known about platelet development, some aspects of platelet production remain poorly understo...

  2. Synthesis and preliminary evaluation of n.c.a. iodoquine: a novel radiotracer with high uptake in cells with high ALDH1 expression.

    Science.gov (United States)

    Chin, Bennett B; Hjelemand, Anita; Rich, Jeremy; Song, Haijing; Lascola, Christopher; Storms, Robert; McLendon, Roger; Reiman, Robert; Greer, Kim L; Metzler, Scott D; McDougald, Darryl; Dai, Diana; Vaidyanathan, Ganesan

    2012-01-01

    Chloroquine has demonstrated high affinity for aldehyde dehydrogenase 1A1 (ALDH1), an enzyme expressed in the highly tumorigenic CD133+ brain tumor initiating subpopulation. The purpose of this study is to report the novel synthesis of a chloroquine analogue, n.c.a. iodoquine, and the in vitro and in vivo uptake in cells with high ALDH1 content. Iodoquine was synthesized in novel no-carrier-added forms (n.c.a.) for both 125I and 123I. I25I IQ and 18F FDG cell uptake assays were performed in the L1210 and L1210cpa (cyclophosphamide resistant), A549, and MG456 glioblastoma cell lines. Uptake was expressed as a percent of the administered activity. 125I IQ biodistribution studies assessed organ uptake at 1, 4, and 24 hours after IV administration (n= 15 total; 5 mice/timepoint). Radiation dosimetry estimates were calculated using standard OLINDA/EXM software. In vivo imaging of 123I IQ uptake in MG456 glioblastoma mouse model (n=10) was performed with small animal high resolution micro-SPECT. Autoradiography and histology co-localized radiotracer and tumor biodistribution. Uptake in MG456 glioblastoma tumors was quantified with gamma counting. L1210 cpa (high ALDH1) showed significantly higher 125I IQ uptake compared to the parental L1210 (low ALDH1) for all time points through 4 hours (20.7% ± 1.4% versus 11.0% ± 0.5%; 21.3% ± 0.9% versus 11.0% ± 0.4%; 20.6% ± 0.7% versus 9.4% ± 0.3%; and 15.7% ± 0.7% versus 7.5% + 0.4% at 30 minutes, and 1, 2 and 4 hours, respectively; p 0.001 for all time points). The A549 lung cancer cell line also showed high IQ uptake through 4 hours. IQ normal biodistribution studies showed rapid renal excretion and very low normal background brain activity after IV administration. In vivo micro-SPECT images showed mild uptake in larger MG456 glioblastomas (n=6) as verified with autoradiography and histology. Gamma well counter uptake in large tumors was 2.3% ± 0.48% ID/g (n=5). Iodoquine localizes to cells with high ALDH1 content. Cell

  3. Clinical Translation of a Dual Integrin αvβ3- and Gastrin-Releasing Peptide Receptor-Targeting PET Radiotracer, 68Ga-BBN-RGD.

    Science.gov (United States)

    Zhang, Jingjing; Niu, Gang; Lang, Lixin; Li, Fang; Fan, Xinrong; Yan, Xuefeng; Yao, Shaobo; Yan, Weigang; Huo, Li; Chen, Libo; Li, Zhiyuan; Zhu, Zhaohui; Chen, Xiaoyuan

    2017-02-01

    This study aimed to document the first-in-human application of a (68)Ga-labeled heterodimeric peptide BBN-RGD (bombesin-RGD) that targets both integrin αvβ3 and gastrin-releasing peptide receptor (GRPR). We evaluated the safety and assessed the clinical diagnostic value of (68)Ga-BBN-RGD PET/CT in prostate cancer patients in comparison with (68)Ga-BBN. Five healthy volunteers (4 men and 1 woman; age range, 28-53 y) were enrolled to validate the safety of (68)Ga-BBN-RGD. Dosimetry was calculated using the OLINDA/EXM software. Thirteen patients with prostate cancer (4 newly diagnosed and 9 posttherapy) were enrolled. All the patients underwent PET/CT scans 15-30 min after intravenous injection of 1.85 MBq (0.05 mCi) per kilogram of body weight of (68)Ga-BBN-RGD and also accepted (68)Ga-BBN PET/CT within 2 wk for comparison. With a mean injected dose of 107.3 ± 14.8 MBq per patient, no side effect was found during the whole procedure and 2 wk follow-up, demonstrating the safety of (68)Ga-BBN-RGD. A patient would be exposed to a radiation dose of 2.90 mSv with an injected dose of 129.5 MBq (3.5 mCi), which is much lower than the dose limit set by the Food and Drug Administration. In 13 patients with prostate cancer diagnosed by biopsy, (68)Ga-BBN-RGD PET/CT detected 3 of 4 primary tumors, 14 metastatic lymph nodes, and 20 bone lesions with an SUVmax of 4.46 ± 0.50, 6.26 ± 2.95, and 4.84 ± 1.57, respectively. Only 2 of 4 primary tumors, 5 lymph nodes, and 12 bone lesions were positive on (68)Ga-BBN PET/CT, with the SUVmax of 2.98 ± 1.24, 4.17 ± 1.89, and 3.61 ± 1.85, respectively. This study indicates the safety and efficiency of a new type of dual integrin αvβ3- and GRPR-targeting PET radiotracer in prostate cancer diagnosis and staging. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

  4. Systemic catechol-O-methyl transferase inhibition enables the D{sub 1} agonist radiotracer R-[{sup 11}C]SKF 82957

    Energy Technology Data Exchange (ETDEWEB)

    Palner, Mikael, E-mail: mikael.palner@nru.d [Neurobiology Research Unit, Rigshospitalet and University of Copenhagen, Copenhagen (Denmark); Center for Integrated Molecular Brain Imaging, Rigshospitalet (Denmark); McCormick, Patrick; Parkes, Jun [PET Center, Center for Addiction and Mental Health, Toronto, Ontario (Canada); Knudsen, Gitte M. [Neurobiology Research Unit, Rigshospitalet and University of Copenhagen, Copenhagen (Denmark); Center for Integrated Molecular Brain Imaging, Rigshospitalet (Denmark); Wilson, Alan A. [PET Center, Center for Addiction and Mental Health, Toronto, Ontario (Canada); Department of Psychiatry, University of Toronto, Toronto, Ontario (Canada)

    2010-10-15

    Introduction: R-[{sup 11}C]-SKF 82957 is a high-affinity and potent dopamine D{sub 1} receptor agonist radioligand, which gives rise to a brain-penetrant lipophilic metabolite. In this study, we demonstrate that systemic administration of catechol-O-methyl transferase (COMT) inhibitors blocks this metabolic pathway, facilitating the use of R-[{sup 11}C]-SKF 82957 to image the high-affinity state of the dopamine D{sub 1} receptor with PET. Methods: R-[{sup 11}C]SKF 82957 was administered to untreated and COMT inhibitor-treated conscious rats, and the radioactive metabolites present in the brain and plasma were quantified by HPLC. Under optimal conditions, cerebral uptake and dopamine D{sub 1} binding of R-[{sup 11}C]SKF 82957 were measured ex vivo. In addition, pharmacological challenges with the receptor antagonist SCH 23390, amphetamine, the dopamine reuptake inhibitor RTI-32 and the dopamine hydroxylase inhibitor {alpha}-methyl-p-tyrosine were performed to study the specificity and sensitivity of R-[{sup 11}C]-SKF 82957 dopamine D{sub 1} binding in COMT-inhibited animals. Results: Treatment with the COMT inhibitor tolcapone was associated with a dose-dependent (EC{sub 90} 5.3{+-}4.3 mg/kg) reduction in the lipophilic metabolite. Tolcapone treatment (20 mg/kg) also resulted in a significant increase in the striatum/cerebellum ratio of R-[{sup 11}C]SKF 82957, from 15 (controls) to 24. Treatment with the dopamine D{sub 1} antagonist SCH 23390 reduced the striatal binding to the levels of the cerebellum, demonstrating a high specificity and selectivity of R-[{sup 11}C]SKF 82957 binding. Conclusions: Pre-treatment with the COMT inhibitor tolcapone inhibits formation of an interfering metabolite of R-[{sup 11}C]SKF 82957. Under such conditions, R-[{sup 11}C]SKF 82957 demonstrates high potential as the first agonist radiotracer for imaging the dopamine D{sub 1} receptor by PET.

  5. Evaluation of two novel {sup 64}Cu-labeled RGD peptide radiotracers for enhanced PET imaging of tumor integrin α{sub v}β{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, Reinier; Graves, Stephen A.; Nickles, Robert J. [University of Wisconsin, Department of Medical Physics, Madison, WI (United States); Czerwinski, Andrzej; Valenzuela, Francisco [Peptides International, Inc., Louisville, KY (United States); Chakravarty, Rubel; Yang, Yunan; England, Christopher G. [University of Wisconsin, Department of Radiology, Madison, WI (United States); Cai, Weibo [University of Wisconsin, Department of Medical Physics, Madison, WI (United States); University of Wisconsin, Department of Radiology, Madison, WI (United States); University of Wisconsin Carbone Cancer Center, Madison, WI (United States)

    2015-11-15

    Our goal was to demonstrate that suitably derivatized monomeric RGD peptide-based PET tracers, targeting integrin α{sub v}β{sub 3}, may offer advantages in image contrast, time for imaging, and low uptake in nontarget tissues. Two cyclic RGDfK derivatives, (PEG){sub 2}-c(RGDfK) and PEG{sub 4}-SAA{sub 4}-c(RGDfK), were constructed and conjugated to NOTA for {sup 64}Cu labeling. Their integrin α{sub v}β{sub 3}-binding properties were determined via a competitive cell binding assay. Mice bearing U87MG tumors were intravenously injected with each of the {sup 64}Cu-labeled peptides, and PET scans were acquired during the first 30 min, and 2 and 4 h after injection. Blocking and ex vivo biodistribution studies were carried out to validate the PET data and confirm the specificity of the tracers. The IC{sub 50} values of NOTA-(PEG){sub 2}-c(RGDfK) and NOTA-PEG{sub 4}-SAA{sub 4}-c(RGDfK) were 444 ± 41 nM and 288 ± 66 nM, respectively. Dynamic PET data of {sup 64}Cu-NOTA-(PEG){sub 2}-c(RGDfK) and {sup 64}Cu-NOTA-PEG{sub 4}-SAA{sub 4}-c(RGDfK) showed similar circulation t{sub 1/2} and peak tumor uptake of about 4 %ID/g for both tracers. Due to its marked hydrophilicity, {sup 64}Cu-NOTA-PEG{sub 4}-SAA{sub 4}-c(RGDfK) provided faster clearance from tumor and normal tissues yet maintained excellent tumor-to-background ratios. Static PET scans at later time-points corroborated the enhanced excretion of the tracer, especially from abdominal organs. Ex vivo biodistribution and receptor blocking studies confirmed the accuracy of the PET data and the integrin α{sub v}β{sub 3}-specificity of the peptides. Our two novel RGD-based radiotracers with optimized pharmacokinetic properties allowed fast, high-contrast PET imaging of tumor-associated integrin α{sub v}β{sub 3}. These tracers may facilitate the imaging of abdominal malignancies, normally precluded by high background uptake. (orig.)

  6. A molecular density functional theory to study solvation in water

    CERN Document Server

    Jeanmairet, Guillaume

    2014-01-01

    A classical density functional theory is applied to study solvation of solutes in water. An approx- imate form of the excess functional is proposed for water. This functional requires the knowledge of pure solvent direct correlation functions. Those functions can be computed by using molecular simulations such as molecular dynamic or Monte Carlo. It is also possible to use functions that have been determined experimentally. The functional minimization gives access to the solvation free energy and to the equilibrium solvent density. Some correction to the functional are also proposed to get the proper tetrahedral order of solvent molecules around a charged solute and to reproduce the correct long range hydrophobic behavior of big apolar solutes. To proceed the numerical minimization of the functional, the theory has been discretized on two tridimensional grids, one for the space coordinates, the other for the angular coordinates, in a functional minimization code written in modern Fortran, mdft. This program i...

  7. Application of 99mTc-DTPA Radiotracer in Persian Cat's Renal ...

    African Journals Online (AJOL)

    renal organ. dministration of the radioisotope and accumulation of ... cat's renal scintigraphy, and this makes it potentially useful in research and ... system, this compound is excreted by the ... studies from animal and environment were done.

  8. How to Perform and Interpret Functional Magnetic Resonance Imaging Studies in Functional Gastrointestinal Disorders.

    Science.gov (United States)

    Lee, In-Seon; Preissl, Hubert; Enck, Paul

    2017-04-30

    Functional neuroimaging studies have revealed the importance of the role of cognitive and psychological factors and the dysregulation of the brain-gut axis in functional gastrointestinal disorder patients. Although only a small number of neuroimaging studies have been conducted in functional gastrointestinal disorder patients, and despite the fact that the neuroimaging technique requires a high level of knowledge, the technique still has a great deal of potential. The application of functional magnetic resonance imaging (fMRI) technique in functional gastrointestinal disorders should provide novel methods of diagnosing and treating patients. In this review, basic knowledge and technical/practical issues of fMRI will be introduced to clinicians.

  9. Evaluation of the In Vivo and Ex Vivo Binding of Novel BC1 Cannabinoid Receptor Radiotracers

    Energy Technology Data Exchange (ETDEWEB)

    Miller, A.; Gatley, J.; Gifford, A.

    2002-01-01

    The primary active ingredient of marijuana, 9-tetrahydrocannabinol, exerts its psychoactive effects by binding to cannabinoid CB1 receptors. These receptors are found throughout the brain with high concentrations in the hippocampus and cerebellum. The current study was conducted to evaluate the binding of a newly developed putative cannabinoid antagonist, AM630, and a classical cannabinoid 8-tetrahydrocannabinol as potential PET and/or SPECT imaging agents for brain CB1 receptors. For both of these ligands in vivo and ex vivo studies in mice were conducted. AM630 showed good overall brain uptake (as measure by %IA/g) and a moderately rapid clearance from the brain with a half-clearance time of approximately 30 minutes. However, AM630 did not show selective binding to CB1 cannabinoid receptors. Ex vivo autoradiography supported the lack of selective binding seen in the in vivo study. Similar to AM630, 8-tetrahydrocanibol also failed to show selective binding to CB1 receptor rich brain areas. The 8-tetrahydrocanibol showed moderate overall brain uptake and relatively slow brain clearance as compared to AM630. Further studies were done with AM2233, a cannabinoid ligand with a similar structure as AM630. These studies were done to develop an ex vivo binding assay to quantify the displacement of [131I]AM2233 binding by other ligands in Swiss-Webster and CB1 receptor knockout mice. By developing this assay we hoped to determine the identity of an unknown binding site for AM2233 present in the hippocampus of CB1 knockout mice. Using an approach based on incubation of brain slices prepared from mice given intravenous [131I]AM2233 in either the presence or absence of AM2233 (unlabelled) it was possible to demonstrate a significant AM2233-displacable binding in the Swiss-Webster mice. Future studies will determine if this assay is appropriate for identifying the unknown binding site for AM2233 in the CB1 knockout mice.

  10. Functional approaches in translation studies in Germany Functional approaches in translation studies in Germany

    Directory of Open Access Journals (Sweden)

    Paul Kussmaul

    2008-04-01

    Full Text Available In the early phase of translation studies in Germany, contrastive linguistics played a major role. I shall briefly describe this approach so that the functional approach will become clearer by contrast. Influenced by the representatives of stylistique comparée, Vinay/Darbelnet (1968 Wolfram Wilss, for instance, in his early work (1971, 1977 makes frequent use of the notion transposition (German “Ausdrucksverschiebung“, cf. also Catford’s (1965 term shift. As a whole, of course, Wilss’ work has a much broader scope. More recently, he has investigated the role of cognition (1988 and the various factors in translator behaviour (1996. Nevertheless, transposition is still a very important and useful notion in describing the translation process. The need for transpositions arises when there is no possibility of formal one-to-one correspondence between source and target-language structures. The basic idea is that whenever there is a need for transposition, we are faced with a translation problem. In the early phase of translation studies in Germany, contrastive linguistics played a major role. I shall briefly describe this approach so that the functional approach will become clearer by contrast. Influenced by the representatives of stylistique comparée, Vinay/Darbelnet (1968 Wolfram Wilss, for instance, in his early work (1971, 1977 makes frequent use of the notion transposition (German “Ausdrucksverschiebung“, cf. also Catford’s (1965 term shift. As a whole, of course, Wilss’ work has a much broader scope. More recently, he has investigated the role of cognition (1988 and the various factors in translator behaviour (1996. Nevertheless, transposition is still a very important and useful notion in describing the translation process. The need for transpositions arises when there is no possibility of formal one-to-one correspondence between source and target-language structures. The basic idea is that whenever there is a need for

  11. Synthesis and Evaluation of New Generation Cross-Bridged Bifunctional Chelator for (64)Cu Radiotracers.

    Science.gov (United States)

    Dale, Ajit V; An, Gwang Il; Pandya, Darpan N; Ha, Yeong Su; Bhatt, Nikunj; Soni, Nisarg; Lee, Hochun; Ahn, Heesu; Sarkar, Swarbhanu; Lee, Woonghee; Huynh, Phuong Tu; Kim, Jung Young; Gwon, Mi-Ri; Kim, Sung Hong; Park, Jae Gyu; Yoon, Young-Ran; Yoo, Jeongsoo

    2015-09-08

    Bifunctional chelators have been successfully used to construct (64)Cu-labeled radiopharmaceuticals. Previously reported chelators with cross-bridged cyclam backbones have various essential features such as high stability of the copper(II) complex, high efficiency of radiolabeling at room temperature, and good biological inertness of the radiolabeled complex, along with rapid body clearance. Here, we report a new generation propylene-cross-bridged chelator with hybrid acetate/phosphonate pendant groups (PCB-TE1A1P) developed with the aim of combining these key properties in a single chelator. The PCB-TE1A1P was synthesized from cyclam with good overall yield. The Cu(II) complex of our chelator showed good robustness in kinetic stability evaluation experiments, such as acidic decomplexation and cyclic voltammetry studies. The Cu(II) complex of PCB-TE1A1P remained intact under highly acidic conditions (12 M HCl, 90 °C) for 8 d and showed quasi-reversible reduction/oxidation peaks at -0.77 V in electrochemical studies. PCB-TE1A1P was successfully radiolabeled with (64)Cu ions in an acetate buffer at 60 °C within 60 min. The electrophoresis study revealed that the (64)Cu-PCB-TE1A1P complex has net negative charge in aqueous solution. The biodistribution and in vivo stability study profiles of (64)Cu-PCB-TE1A1P indicated that the radioactive complex was stable under physiological conditions and cleared rapidly from the body. A whole body positron emission tomography (PET) imaging study further confirmed high in vivo stability and fast clearance of the complex in mouse models. In conclusion, PCB-TE1A1P has good potential as a bifunctional chelator for (64)Cu-based radiopharmaceuticals, especially those involving peptides.

  12. Intestinal uptake of bone seeking radiotracer: possible mechanisms and review of the literature

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D. W.; Kim, C. G.; Park, S. A.; Chang, J. A. [WonKwang University Hospital, Iksan (Korea, Republic of)

    2007-07-01

    This study was undertaken to investigate the frequency of intestinal accumulation of Tc-99m 3, 3-diphosphono-1, 2-propanedicarboxylic acid (DPD) on bone scans, describe the patterns of intestinal Tc-99m DPD uptake and discuss the possible mechanisms of this unusual finding. Three thousand, one hundred and ninety-four consecutive patients have been evaluated for intestinal Tc-99m DPD uptake on bone scans. A whole-body bone scan and various spot views were obtained to evaluate the location and intensity of intestinal uptake. Delayed scan and SPECT study were performed to define characteristics of intestinal uptake in some of patients. Available reports of co-relative radiologic imaging, endoscopic studies and laboratory tests were also reviewed to explain the intestinal uptake. Eighteen (9 female, 9 male) patients out of 3194 with a mean age of 57 years showed intestinal Tc-99m DPD uptake. The locations of intestinal uptake were well dispersed throughout the abdomen. The majority of the cases showed lower intensity than iliac spine (12/18, 67%). Eight patients didn't show significant change of uptake characteristics on the delayed images, while intestinal uptake traveled distally in nine patients. Two cases were revealed uptake of peritoneal carcinomatosis with small amount ascites and three cases were revealed tumoral uptake of intestine. Four patients with gastritis showed similar characteristic of intestinal uptake. Six cases of distally traveled intestinal uptake suggested intraluminal Tc-99m DPD activity such as gastrointestinal bleeding. However, stool occult blood tests were negative in three patients, and there is no clinical evidence of gastrointestinal bleeding in other three patients. Intestinal Tc-99m DPD uptake can be observed in 0.5% of bone scans. The mechanism of intestinal uptake is still unclear in some of the patients. Delayed imaging additional spot views and SPECT studies help in the differentiation of this finding from possible

  13. How do brain tumors alter functional connectivity? : A magnetoencephalography study

    NARCIS (Netherlands)

    Bartolomei, Fabrice; Bosma, Ingeborg; Klein, Martin; Baayen, Johannes C; Reijneveld, Jaap C; Postma, Tjeerd J; Heimans, Jan J; van Dijk, Bob W; de Munck, Jan C; de Jongh, Arent; Cover, Keith S; Stam, Cornelis J

    2006-01-01

    OBJECTIVE: This study was undertaken to test the hypothesis that brain tumors interfere with normal brain function by disrupting functional connectivity of brain networks. METHODS: Functional connectivity was assessed by computing the synchronization likelihood in a broad band (0.5-60Hz) or in the g

  14. Familial Essential Tremor Studied With Functional Magnetic Resonance Imaging

    Science.gov (United States)

    Hernandez, A.; Salgado, P.; Gil, A.; Barrios, F. A.

    2003-09-01

    Functional Magnetic Resonance Imaging has become an important analytical tool to study neurodegenerative diseases. We applied the EPI-BOLD functional Magnetic Resonance Imaging technique to acquire functional images of patients with familial essential tremor (FET) disorder and healthy control volunteers, during a motor task activity. Functional and anatomic images were used to produce the brain activation maps of the patients and volunteers. These functional maps of the primary somatosensorial and motor cortexes of patients and control subjects were compared for functional differences per subject. The averaged functional brain images of eight of each case were acquired were, it can be clearly observed the differences in active zones. The results presented in this work show that there are differences in the functional maps during motor task activation between control subjects and FET patients suggesting a cerebral functional reorganization that can be mapped with BOLD-fMRI.

  15. In vivo evaluation in rats of [{sup 18}F]1-(2-fluoroethyl)-4-[(4-cyanophenoxy)methyl]piperidine as a potential radiotracer for PET assessment of CNS sigma-1 receptors

    Energy Technology Data Exchange (ETDEWEB)

    Waterhouse, Rikki N. [Department of Psychiatry, Columbia University, New York, NY 10032 (United States) and Department of Radiology, Columbia University, New York, NY 10032 (United States) and Neurobiology and Imaging Program, Department of Biological Psychiatry, New York State Psychiatric Institute, New York, NY 10032 (United States)]. E-mail: rnw7@columbia.edu; Chang, Raymond C. [Department of Psychiatry, Columbia University, New York, NY 10032 (United States); Neurobiology and Imaging Program, Department of Biological Psychiatry, New York State Psychiatric Institute, New York, NY 10032 (United States); Zhao, Jun [Department of Psychiatry, Columbia University, New York, NY 10032 (United States); Neurobiology and Imaging Program, Department of Biological Psychiatry, New York State Psychiatric Institute, New York, NY 10032 (United States); Carambot, Patty E. [Department of Psychiatry, Columbia University, New York, NY 10032 (United States); Neurobiology and Imaging Program, Department of Biological Psychiatry, New York State Psychiatric Institute, New York, NY 10032 (United States)

    2006-02-15

    Introduction: Sigma-1 receptors are expressed throughout the mammalian central nervous system (CNS) and are implicated in several psychiatric disorders, including schizophrenia and depression. We have recently evaluated the high-affinity (K {sub D}=0.5{+-}0.2 nM, log P=2.9) sigma-1 receptor radiotracer [{sup 18}F]1-(3-fluoropropyl)-4-(4-cyanophenoxymethyl)piperidine, [{sup 18}F]FPS, in humans. In contrast to appropriate kinetics exhibited in baboon brain, in the human CNS, [{sup 18}F]FPS does not reach pseudoequilibrium by 4 h, supporting the development of a lower-affinity tracer [Waterhouse RN, Nobler MS, Chang RC, Zhou Y, Morales O, Kuwabara H, et al. First evaluation of the sigma-1 receptor radioligand [{sup 18}F]1-3-fluoropropyl-4-((4-cyanophenoxy)-methyl)piperidine ([{sup 18}F]FPS) in healthy humans. Neuroreceptor Mapping 2004, July 15-18th, Vancouver, BC Canada 2004]. We describe herein the in vivo evaluation in rats of [{sup 18}F]1-(2-fluoroethyl)-4-[(4-cyanophenoxy)methyl]piperidine ([{sup 18}F]SFE) (K {sub D}=5 nM, log P=2.4), a structurally similar, lower-affinity sigma-1 receptor radioligand. Methods: [{sup 18}F]SFE was synthesized (n=4) as previously described in good yield (54{+-}6% EOB), high specific activity (2.1{+-}0.6 Ci/{mu}mol EOS) and radiochemical purity (98{+-}1%) and evaluated in awake adult male rats. Results: Similar to [{sup 18}F]FPS, regional brain radioactivity concentrations [percentage of injected dose per gram of tissue (%ID/g), 15 min] for [{sup 18}F]SFE were highest in occipital cortex (1.86{+-}0.06 %ID/g) and frontal cortex (1.76{+-}0.38 %ID/g), and lowest in the hippocampus (1.01{+-}0.02%ID/g). Unlike [{sup 18}F]FPS, [{sup 18}F]SFE cleared from the brain with {approx}40% reduction in peak activity over a 90-min period. Metabolite analysis (1 h) revealed that [{sup 18}F]SFE was largely intact in the brain. Blocking studies showed a large degree (>80%) of saturable binding for [{sup 18}F]SFE in discrete brain regions. Conclusions

  16. [11C] labeled erlotinib as a new radiotracer for identification of patients responding to erlotinib treatment

    DEFF Research Database (Denmark)

    Memon, Ashfaque Ahmed; Weber, Britta; Jakobsen, Steen;

    2009-01-01

    Erlotinib (Tarceva®) is a tailored drug targeting the Epidermal Growth Factor Receptor (EGFR), which is commonly overexpressed in various human cancers including lung cancer. The purpose of this study was to develop a method for identification of lung cancer patients that respond to erlotinib...... treatment by PET scanning. We demonstrate that erlotinib can be labeled with [11C] by reacting the normethyl precursor with [11C] methyl iodide followed by HPLC purification. First we tested [11C] erlotinib on nude mice xenografted with lung cancer cell lines with either a high (A549, NCI358) or low (HCC827...

  17. About the detergent efficiency: Investigations with the radiotracer technique. Ueber die Waschwirkung: Untersuchungen mit der Radiotracertechnik

    Energy Technology Data Exchange (ETDEWEB)

    Wasow, G. (Zentralinstitut fuer Organische Chemie, Berlin (Germany). Bereich Grenzflaechenaktive Stoffe)

    The washing process is a complex matter. It demands cooperation of a lot of components in a built detergent. The results, however, are influenced by the chemical structure of the surface of a solid substrate and its morphology as well as the kind of soil involved. Therefore the efficiency of surfactants was studied under direct influence of the solid surface. Attractive forces from the solid surface have a limited range only. {sup 14}C-labelled oleophilic or surface-active substances have been used for the quantitative evaluation of the thin layers influenced. (orig./BBR).

  18. Marine anthropogenic radiotracers in the Southern Hemisphere: New sampling and analytical strategies

    DEFF Research Database (Denmark)

    Levy, I.; Povinec, P.P.; Aoyama, M.

    2011-01-01

    The Japan Agency for Marine Earth Science and Technology conducted in 2003–2004 the Blue Earth Global Expedition (BEAGLE2003) around the Southern Hemisphere Oceans, which was a rare opportunity to collect many seawater samples for anthropogenic radionuclide studies. We describe here sampling...... and analytical methodologies based on radiochemical separations of Cs and Pu from seawater, as well as radiometric and mass spectrometry measurements. Several laboratories took part in radionuclide analyses using different techniques. The intercomparison exercises and analyses of certified reference materials...

  19. Determination of the hydraulic residence time of trickling filters using radiotracer experiments

    Energy Technology Data Exchange (ETDEWEB)

    Debien, Bruno R.; Ferreira, Ladislau M.; Barreto, Alberto A.; Pinto, Amenonia M.F., E-mail: brunordebien@gmail.com [Universidade Federal de Minas Gerais (UFMG), Minas Gerais, MG (Brazil). Dept. de Geografia. Lab. de Geomorfologia; Moreira, Rubens M., E-mail: aab@cdtn.br, E-mail: amfp@cdtn.br, E-mail: rubens@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    Trickling filters (TF) are bioreactors fulfilled with inert materials working as support for biofilm development, and have been used in a large scale in wastewater treatment for organic matter, ammonia nitrogen and nitrate removal. TF's can be widely used in Brazil, especially because of its simplicity and operational low cost. The efficiency of pollutants removal processes depends on the water flow dynamics inside the reactor. For this reason, in the present work the mean residence time of two TF's containing different support materials were determined by means of tracer testes. The radioisotope 82Br - a gamma radiation emitter, produced from soluble potassium bromide irradiated in the TRIGA reactor at the Centre for the Development of Nuclear Energy (CDTN) - was used as a pseudo-conservative tracer for the comparative study of aqueous phase flow dynamics in both TF's. Mean residence time for the first TF (containing a single support material) was 0,3 hours, much smaller than the value obtained for the second TF (containing two alternated support materials), around 2 hours. These results were already expected, once the alternated material is denser than the single one, and are very important for numerical modeling studies aiming to determine the kinetic constant for removal of the pollutants cited above. (author)

  20. Separation of lanthanum, hafnium, barium and radiotracers yttrium-88 and barium-133 using crystalline zirconium phosphate and phosphonate compounds as prospective materials for a Ra-223 radioisotope generator

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, Teresia [Lynntech Inc., 7610 Eastmark Dr, College Station, TX 77840 (United States); Bestaoui, Naima, E-mail: Naima.Bestaoui@Lynntech.co [Lynntech Inc., 7610 Eastmark Dr, College Station, TX 77840 (United States); Wierzbicki, Melissa; Adams, Todd; Clearfield, Abraham [Lynntech Inc., 7610 Eastmark Dr, College Station, TX 77840 (United States)

    2011-07-15

    Crystalline hybrid organic/inorganic ion exchangers based on zirconium phosphate and phosphonate compounds were evaluated for application in radium-223 generator for radiopharmaceutical applications. Various compositions were synthesized and the selectivity of these materials was determined for inactive lanthanum, hafnium and barium, and radiotracers yttrium-88 and barium-133. The hybrid materials show very efficient lanthanum/barium separation; the response for zirconium phosphate was even better. A small-scale column loaded with pelletized zirconium phosphate compound demonstrated excellent retention of {sup 88}Y and release of {sup 133}Ba.

  1. Dopamine D2 receptor radiotracers [{sup 11}C](+)-PHNO and [{sup 3}H]raclopride are indistinguishably inhibited by D2 agonists and antagonists ex vivo

    Energy Technology Data Exchange (ETDEWEB)

    McCormick, Patrick N. [Institute of Medical Science, University of Toronto, Toronto, Ontario, M5S 1A8 (Canada)], E-mail: patrick.mccormick@camhpet.ca; Kapur, Shitij [Department of Psychiatry, University of Toronto, Toronto, Ontario, M5S 1A8 (Canada); PET Center, Center for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada); Seeman, Philip [Department of Psychiatry, University of Toronto, Toronto, Ontario, M5S 1A8 (Canada); Department of Pharmacology, University of Toronto, Toronto, Ontario, M5S 1A8 (Canada); Wilson, Alan A. [Department of Psychiatry, University of Toronto, Toronto, Ontario, M5S 1A8 (Canada); PET Center, Center for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada)

    2008-01-15

    Introduction: In vitro, the dopamine D2 receptor exists in two states, with high and low affinity for agonists. The high-affinity state is the physiologically active state thought to be involved in dopaminergic illnesses such as schizophrenia. The positron emission tomography radiotracer [{sup 11}C](+)-PHNO ([{sup 11}C](+)-4-propyl-3,4,4a,5,6,10b-hexahydro-2H-naphtho[1,2-b][1,4] oxazin-9-o l), being a D2 agonist, should selectively label the high-affinity state at tracer dose and therefore be more susceptible to competition by agonist as compared to the antagonist [{sup 3}H]raclopride, which binds to both affinity states. Methods: We tested this prediction using ex vivo dual-radiotracer experiments in conscious rats. D2 antagonists (haloperidol or clozapine), a partial agonist (aripiprazole), a full agonist [(-)-NPA] or the dopamine-releasing drug amphetamine (AMPH) were administered to rats prior to an intravenous coinjection of [{sup 11}C](+)-PHNO and [{sup 3}H]raclopride. Rats were sacrificed 60 min after radiotracer injection. Striatum, cerebellum and plasma samples were counted for {sup 11}C and {sup 3}H. The specific binding ratio {l_brace}SBR, i.e., [%ID/g (striatum)-%ID/g (cerebellum)]/(%ID/g (cerebellum){r_brace} was used as the outcome measure. Results: In response to D2 antagonists, partial agonist or full agonist, [{sup 11}C](+)-PHNO and [{sup 3}H]raclopride SBRs responded indistinguishably in terms of both ED{sub 50} and Hill slope (e.g., (-)-NPA ED{sub 50} values are 0.027 and 0.023 mg/kg for [{sup 11}C](+)-PHNO and [{sup 3}H]raclopride, respectively). In response to AMPH challenge, [{sup 11}C](+)-PHNO and [{sup 3}H]raclopride SBRs were inhibited to the same degree. Conclusions: We have shown that the SBRs of [{sup 11}C](+)-PHNO- and [{sup 3}H]raclopride do not differ in their response to agonist challenge. These results do not support predictions of the in vivo binding behavior of a D2 agonist radiotracer and cast some doubt on the in vivo

  2. Production of Rare Earth Isotope Beams for Radiotracer-DLTS on SiC

    CERN Multimedia

    2002-01-01

    Electrical properties of semiconductors are extremely sensitive to minor traces of impurities and defects. This fact allows to intentionally modify material properties and is thus the very basis of semiconductor electronics and optoelectronics. In the present project, electronic properties and doping effects of rare-earth elements in the technologically important semiconductor SiC are to be investigated using optical and electrical characterization techniques like Photoluminescence, Deep Level Transient Spectroscopy and Thermal Admittance Spectroscopy. By using the elemental transmutation of radioactive isotopes as a tracer, it will be guaranteed that the impurity-related band gap states can definitively be distinguished from intrinsic or process-induced defects. For SiC up to now only detailed investigation of Er- related deep levels have been reported, preliminary data exist for Sm- and Gd- impurities. In this project we propose the implantation of Pr and Eu isotopes for detailed level studies.

  3. Marine anthropogenic radiotracers in the Southern Hemisphere: New sampling and analytical strategies

    Science.gov (United States)

    Levy, I.; Povinec, P. P.; Aoyama, M.; Hirose, K.; Sanchez-Cabeza, J. A.; Comanducci, J.-F.; Gastaud, J.; Eriksson, M.; Hamajima, Y.; Kim, C. S.; Komura, K.; Osvath, I.; Roos, P.; Yim, S. A.

    2011-04-01

    The Japan Agency for Marine Earth Science and Technology conducted in 2003-2004 the Blue Earth Global Expedition (BEAGLE2003) around the Southern Hemisphere Oceans, which was a rare opportunity to collect many seawater samples for anthropogenic radionuclide studies. We describe here sampling and analytical methodologies based on radiochemical separations of Cs and Pu from seawater, as well as radiometric and mass spectrometry measurements. Several laboratories took part in radionuclide analyses using different techniques. The intercomparison exercises and analyses of certified reference materials showed a reasonable agreement between the participating laboratories. The obtained data on the distribution of 137Cs and plutonium isotopes in seawater represent the most comprehensive results available for the Southern Hemisphere Oceans.

  4. Samarium oxide as a radiotracer to evaluate the in vivo biodistribution of PLGA nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Mandiwana, Vusani, E-mail: VMandiwana@csir.co.za; Kalombo, Lonji, E-mail: LKalombo@csir.co.za [Centre of Polymers and Composites, CSIR (South Africa); Venter, Kobus, E-mail: Kobus.Venter@mrc.ac.za [South African Medical Research Council (South Africa); Sathekge, Mike, E-mail: Mike.Sathekge@up.ac.za [University of Pretoria and Steve Biko Academic Hospital, Department of Nuclear Medicine (South Africa); Grobler, Anne, E-mail: Anne.Grobler@nwu.ac.za; Zeevaart, Jan Rijn, E-mail: zeevaart@necsa.co.za [North-West University, DST/NWU Preclinical Drug Development Platform (South Africa)

    2015-09-15

    Developing nanoparticulate delivery systems that will allow easy movement and localization of a drug to the target tissue and provide more controlled release of the drug in vivo is a challenge in nanomedicine. The aim of this study was to evaluate the biodistribution of poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles containing samarium-153 oxide ([{sup 153}Sm]Sm{sub 2}O{sub 3}) in vivo to prove that orally administered nanoparticles alter the biodistribution of a drug. These were then activated in a nuclear reactor to produce radioactive {sup 153}Sm-loaded-PLGA nanoparticles. The nanoparticles were characterized for size, zeta potential, and morphology. The nanoparticles were orally and intravenously (IV) administered to rats in order to trace their uptake through imaging and biodistribution studies. The {sup 153}Sm-loaded-PLGA nanoparticles had an average size of 281 ± 6.3 nm and a PDI average of 0.22. The zeta potential ranged between 5 and 20 mV. The [{sup 153}Sm]Sm{sub 2}O{sub 3} loaded PLGA nanoparticles, orally administered were distributed to most organs at low levels, indicating that there was absorption of nanoparticles. While the IV injected [{sup 153}Sm]Sm{sub 2}O{sub 3}-loaded PLGA nanoparticles exhibited the highest localization of nanoparticles in the spleen (8.63 %ID/g) and liver (3.07 %ID/g), confirming that nanoparticles are rapidly removed from the blood by the RES, leading to rapid uptake in the liver and spleen. From the biodistribution data obtained, it is clear that polymeric nanoscale delivery systems would be suitable for improving permeability and thus the bioavailability of therapeutic compounds.

  5. Validation of methodology for determination of the mercury methylation potential in sediments using radiotracers.

    Science.gov (United States)

    Zizek, Suzana; Ribeiro Guevara, Sergio; Horvat, Milena

    2008-04-01

    Experiments to determine the mercury methylation potential were performed on sediments from two locations on the river Idrijca (Slovenia), differing in ambient mercury concentrations. The tracer used was the radioactive isotope (197)Hg. The benefit of using this tracer is its high specific activity, which enables spikes as low as 0.02 ng Hg(2+) g(-1) of sample to be used. It was therefore possible to compare the efficiency of the methylation potential experiments over a range of spike concentrations from picogram to microgram levels. The first part of the work aimed to validate the experimental blanks and the second part consisted of several series of incubation experiments on two different river sediments using a range of tracer additions. The results showed high variability in the obtained methylation potentials. Increasing Hg(2+) additions gave a decrease in the percentage of the tracer methylated during incubation; in absolute terms, the spikes that spanned four orders of magnitude (0.019-190 pg g(-1) of sediment slurry) resulted in MeHg formation between 0.01 and 0.1 ng MeHg g(-1) in Podroteja and Kozarska Grapa. Higher spikes resulted in slightly elevated MeHg production (up to a maximum of 0.27 ng g(-1)). The values of methylation potential were similar in both sediments. The results imply that the experimental determination of mercury methylation potential strongly depends on the experimental setup itself and the amount of tracer added to the system under study. It is therefore recommended to use different concentrations of tracer and perform the experiments in several replicates. The amount of mercury available for methylation in nature is usually very small. Therefore, adding very low amounts of tracer in the methylation potential studies probably gives results that have a higher environmental relevance. It is also suggested to express the results obtained in absolute amounts of MeHg produced and not just as the percentage of the added tracer.

  6. Studies of pituitary function in lactating ewes.

    Science.gov (United States)

    Restall, B J; Kearins, R D; Starr, B G

    1977-03-01

    The release of LH from the pituitary of lactating ewes was studied. In Exp. 1, ewes were injected with 50 microng oestradiol benzoate (OB), 2-0 mg testosterone propionate (TP) or oil only (control) on days 5, 10, or 20 after lambing. LH was measured in peripheral plasma samples obtained 20-38 h after treatment, and the ovulations were recorded. The number of ewes in which an LH release was detected, and the amount released, declined between Day 5 and 20 after OB treatment but increased after TP treatment. The releases of LH were not always accompanied by ovulation and the incidence of ovulation was higher in ewes treated with TP. In Exp. 2, lactating ewes were injected with 1 or 5 (at 2-h intervals) doses of 50 microng Gn-RH, on Days 12 or 25 after lambing. LH was measured in peripheral plasma samples collected every 2 h for 10 h and every 3 h for a further 70 h. Release of LH occurred in all ewes, the amount being greater in ewes receiving multiple injections and in ewes treated on Day 25. The incidence of ovulation was higher after treatment on Day 25. Multiple injections of Gn-RH appeared to reduce the incidence of abnormal corpora lutea.

  7. Validation of methodology for determination of the mercury methylation potential in sediments using radiotracers

    Energy Technology Data Exchange (ETDEWEB)

    Zizek, Suzana; Horvat, Milena [Jozef Stefan Institute, Department of Environmental Sciences, Ljubljana (Slovenia); Ribeiro Guevara, Sergio [Centro Atomico Bariloche, Laboratorio de Analisis por Activacion Neutronica, Bariloche (Argentina)

    2008-04-15

    Experiments to determine the mercury methylation potential were performed on sediments from two locations on the river Idrijca (Slovenia), differing in ambient mercury concentrations. The tracer used was the radioactive isotope {sup 197}Hg. The benefit of using this tracer is its high specific activity, which enables spikes as low as 0.02 ng Hg{sup 2+} g{sup -1} of sample to be used. It was therefore possible to compare the efficiency of the methylation potential experiments over a range of spike concentrations from picogram to microgram levels. The first part of the work aimed to validate the experimental blanks and the second part consisted of several series of incubation experiments on two different river sediments using a range of tracer additions. The results showed high variability in the obtained methylation potentials. Increasing Hg{sup 2+} additions gave a decrease in the percentage of the tracer methylated during incubation; in absolute terms, the spikes that spanned four orders of magnitude (0.019-190 pg g{sup -1} of sediment slurry) resulted in MeHg formation between 0.01 and 0.1 ng MeHg g{sup -1} in Podroteja and Kozarska Grapa. Higher spikes resulted in slightly elevated MeHg production (up to a maximum of 0.27 ng g{sup -1}). The values of methylation potential were similar in both sediments. The results imply that the experimental determination of mercury methylation potential strongly depends on the experimental setup itself and the amount of tracer added to the system under study. It is therefore recommended to use different concentrations of tracer and perform the experiments in several replicates. The amount of mercury available for methylation in nature is usually very small. Therefore, adding very low amounts of tracer in the methylation potential studies probably gives results that have a higher environmental relevance. It is also suggested to express the results obtained in absolute amounts of MeHg produced and not just as the percentage of

  8. Radiosynthesis of [F-18]fluoxetine as a potential radiotracer for serotonin reuptake sites

    Energy Technology Data Exchange (ETDEWEB)

    Das, M.K.; Mukherjee, Jogeshwar (Chicago Univ., IL (United States). Dept. of Radiology)

    1993-05-01

    Synthesis of 4-nitro-[alpha]-bromo-[alpha],[alpha]-difluorotoluene was accomplished in two steps starting from 4-nitrobenzaldehyde, with a 30% overall yield. Radiolabeling of 4-nitro-[alpha]-bromo-[alpha], [alpha]-difluorotoluene with no-carrier-added [[sup 18]F]fluoride provided 4-nitro-[alpha],[alpha]-difluoro-[alpha]-[[sup 18]F] fluorotoluene in 2-4% yields with a specific activity of 2590 GBq/mmol (70 Ci/mmol). The effect of the reaction temperature on the radiochemical yield and specific activity of the radiolabeling reaction was studied. Radiochemical yields increased, whereas specific activity decreased, with increasing temperature. Radiosynthesis of [[sup 18]F] fluoxetine involved coupling of 4-nitro-[alpha],[alpha]-difluoro-[alpha]-[[sup 18]F]fluorotoluene with the sodium alkoxide of (S)-3-(methylamino)-1-phenyl-1-propanol. The overall yield of HPLC purified [[sup 18]F]fluoxetine was 1-2% (decay-corrected; total radiosynthesis time, 150-180 min). The specific activity of the product was 1480 GBq/mmol (40 Ci/mmol). (Author).

  9. Determination of the hydraulic residence time of two subsurface-flow constructed wetlands using radiotracers

    Energy Technology Data Exchange (ETDEWEB)

    Debien, Bruno R., E-mail: brunordebien@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept de Geografia. Lab. de Geomorfologia; Barreto, Alberto A.; Pinto, Amenonia M.F.; Moreira, Rubens M., E-mail: aab@cdtn.br, E-mail: amfp@cdtn.br, E-mail: rubens@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    The adoption of constructed wetland systems (CW's) with subsuperficial drainage for sewage treatment is increasingly growing in places with low technological resources and available land. The efficient removal of pollutants depends on the internal flow characteristics in the CW and on its hydraulic residence time (HRT). In the present work {sup 82}Br - a gamma radiation emitter, produced from soluble potassium bromide irradiated in the TRIGA reactor at the Centre for the Development of Nuclear Energy (CDTN) - was used as a pseudo-conservative tracer for the comparative study of aqueous phase flow dynamics in two CW's: one in which plants were grown (WP) whereas the other had no plants (WNP). Experimental hydraulic residence time values were found to be very close to the theoretical one, while dispersion numbers obtained for both CW's were quite small. Besides these measured hydrodynamic parameters, the residence time distribution (RTD) curves of the tracer test and the results of modeling of experimental data also demonstrate the tendency of the units to display a plug flow-like effluent hydraulic transport within their systems, as expected from their designs, considering the large length/width ratio (L/W=8). (author)

  10. Radiosynthesis and biodistribution of {sup 99m}Tc-rifampicin: A novel radiotracer for in-vivo infection imaging

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Syed Qaiser, E-mail: ssqaiser2002@yahoo.co [Nuclear Medicine Research Laboratory (NMRL), University of Peshawar, Room no 111, Academic Block I, Peshawar, NWFP (Pakistan); Khan, Aakif Ullah [Nuclear Medicine, Oncology and Radiotherapy Institute (NORI), Islamabad (Pakistan); Khan, Muhammad Rafiullah [Phyotopharmaceutical and Neutraceuticals Research Laboratory (PNRL), University of Peshawar, Peshawar, NWFP (Pakistan)

    2010-12-15

    {sup 99m}Tc-rifampicin ({sup 99m}Tc-RMP) a new radioantibiotic complex was synthesized specifically for the infection localization caused by methicillin-resistant Staphylococcus aureus (MRSA). The in-vitro radiochemical purity (RCP) yield, in-vivo biodistribution behavior in artificially infected rats (AIT) and scintigraphic accuracy in artificially infected rabbit (AIB) of the {sup 99m}Tc-RMP complex was investigated using different concentration of the RMP, sodium pertechnetate (Na{sup 99m}TcO{sub 4}), stannous chloride dihydrate (SnCl{sub 2}.2H{sub 2}O) at different pH ranges 5-6. The best RCP yield observed at 30, 60, 90 and 120 min after labeling was; 98.95{+-}0.20, 98.15{+-}0.24, 96.50{+-}0.27 and 91.55{+-}0.22%, respectively, using 1.5 mg RMP, 175 {mu}L of SnCl{sub 2}.2H{sub 2}O (1 {mu}g/{mu}L in 0.01 N HCl), 3 mCi of Na{sup 99m}TcO{sub 4}, at pH 5.6. Initially in the infected muscle (INM) of the AIT the activity was lower but after 90 min it went up to 18.35{+-}0.20% from 5.95{+-}0.25%. The activity in the inflamed muscle (IMM), normal (NM) muscle, blood, liver and spleen was initially high that decreased with time. The ratios of the INM/NM and IMM/NM were 7.34{+-}0.74 and 1.20{+-}0.85, respectively. The whole body static (WBS) imaging of the MRSA infected rabbit confirmed the usefulness of the {sup 99m}Tc-RMP as a precise radiotracer for MRSA infection imaging. On the basis of in-vitro RCP, in-vivo biodistribution and scintigraphic precision, we recommend the {sup 99m}Tc-RMP complex prepared aseptically for in-vivo assessment of MRSA infection.

  11. The Development of Meta-functional Approaches in Translation Studies

    Institute of Scientific and Technical Information of China (English)

    李菁菁

    2012-01-01

      Functional linguistics has exerted an increasing impact on modern linguistic studies. Functional approaches, especial⁃ly metafunctions have undergone a process of development and improvement. The affirmation of the metafunctions of lan⁃guage has aroused more and more scholars’concern on the“functional”facet of language, especially in Translation studies. The formation and improvement of functional approaches are introduced separately.

  12. A Study of I-Function of Several Complex Variables

    OpenAIRE

    Prathima Jayarama; Vasudevan Nambisan Theke Madam; Shantha Kumari Kurumujji

    2014-01-01

    The aim of this paper is to introduce a natural generalization of the well-known, interesting, and useful Fox H-function into generalized function of several variables, namely, the I-function of ‘‘r’’ variables. For r=1, we get the I-function introduced and studied by Arjun Rathie (1997) and, for r=2, we get I-function of two variables introduced very recently by ShanthaKumari et al. (2012). Convergent conditions, elementary properties, and special cases have also been given. T...

  13. Wearable sensor network to study laterality of brain functions.

    Science.gov (United States)

    Postolache, Gabriela B; Girao, Pedro S; Postolache, Octavian A

    2015-08-01

    In the last decade researches on laterality of brain functions have been reinvigorated. New models of lateralization of brain functions were proposed and new methods for understanding mechanisms of asymmetry between right and left brain functions were described. We design a system to study laterality of motor and autonomic nervous system based on wearable sensors network. A mobile application was developed for analysis of upper and lower limbs movements, cardiac and respiratory function. The functionalities and experience gained with deployment of the system are described.

  14. Determination of the particle size distribution in a powder using radiotracers; Determinacion de la distribucion de tamano de particulas en un polvo utilizando radiotrazadores

    Energy Technology Data Exchange (ETDEWEB)

    Revilla D, R

    1974-07-01

    To determine experimentally the particle size distribution in a powder the meshed method is generally used. This method has the disadvantage that in the obtained distribution is not observed at detail the fine structure of such distribution. In this work, a method for obtaining the distribution of particle size using radiotracers is presented. In the obtained distribution by this method it is observed with more detail the fine structure of the distribution, comparing with the obtained results by the classical method of meshed. The radiotracer method has major resolution for the experimental determination mentioned. In the chapter 1, it is done a brief analysis about theoretical aspects related with the method. In the first part it is analysed the particle behavior (sedimenting) in a fluid. The second part treats the relating with the radioactivity of an activated material as well as its detection. In the chapter 2, a description of the method is done also the experimental problems to applying to the alumina crystals sample are discussed. In the chapter 3 the obtained results and the mistake calculations in such results are showed. Finally, in the chapter 4 the conclusions and recommendations are given which is possible to obtain better results and improve to those in this work were obtained. (Author)

  15. Study on Dielectric Function Models for Surface Plasmon Resonance Structure

    Directory of Open Access Journals (Sweden)

    Peyman Jahanshahi

    2014-01-01

    Full Text Available The most common permittivity function models are compared and identifying the best model for further studies is desired. For this study, simulations using several different models and an analytical analysis on a practical surface Plasmon structure were done with an accuracy of ∼94.4% with respect to experimental data. Finite element method, combined with dielectric properties extracted from the Brendel-Bormann function model, was utilized, the latter being chosen from a comparative study on four available models.

  16. Development of dopamine receptor radiopharmaceuticals for the study of neurological and psychiatric disorders

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Jogeshwar Mukherjee

    2009-01-02

    Our goals in this grant application are directed towards the development of radiotracers that may allow the study of the high-affinity state (functional state) of the dopamine receptors. There have been numerous reports on the presence of two inter-convertible states of these (G-protein coupled) receptors in vitro. However, there is no report that establishes the presence of these separate affinity states in vivo. We have made efforts in this direction in order to provide such direct in vivo evidence about the presence of the high affinity state. This understanding of the functional state of the receptors is of critical significance in our overall diagnosis and treatment of diseases that implicate the G-protein coupled receptors. Four specific aims have been listed in the grant application: (1). Design and syntheses of agonists (2). Radiosyntheses of agonists (3). In vitro pharmacology of agonists (4). In vivo distribution and pharmacology of labeled derivatives. We have accomplished the syntheses and radiosyntheses of three agonist radiotracers labeled with carbon-11. In vitro and in vivo pharmacological experiments have been accomplished in rats and preliminary PET studies in non-human primates have been carried out. Various accomplishments during the funded years, briefly outlined in this document, have been disseminated by several publications in various journals and presentations in national and international meetings (Society of Nuclear Medicine, Society for Neuroscience and International Symposium on Radiopharmaceutical Chemistry).

  17. Kinetic-energy functionals studied by surface calculations

    DEFF Research Database (Denmark)

    Vitos, Levente; Skriver, Hans Lomholt; Kollár, J.

    1998-01-01

    The self-consistent jellium model of metal surfaces is used to study the accuracy of a number of semilocal kinetic-energy functionals for independent particles. It is shown that the poor accuracy exhibited by the gradient expansion approximation and most of the semiempirical functionals in the low...

  18. Studying Membrane Protein Structure and Function Using Nanodiscs

    DEFF Research Database (Denmark)

    Huda, Pie

    The structure and dynamic of membrane proteins can provide valuable information about general functions, diseases and effects of various drugs. Studying membrane proteins are a challenge as an amphiphilic environment is necessary to stabilise the protein in a functionally and structurally relevan...

  19. Role of Wigner function in studying quantum correlations

    Science.gov (United States)

    Siyouri, F.; El Baz, M.; Hassouni, Y.

    2016-09-01

    In this paper, we investigate the possibility to use the Wigner function to detect and quantify quantum correlations in general. We study these quantum correlations for two quasi-Werner states formed with two general bipartite superposed squeezed states. We find then that the Wigner function is not sensitive to all kinds of quantum correlations but it only witnesses entanglement.

  20. Graphene on metals: A van der Waals density functional study

    DEFF Research Database (Denmark)

    Vanin, Marco; Mortensen, Jens Jørgen; Kelkkanen, Kari André;

    2010-01-01

    We use density functional theory (DFT) with a recently developed van der Waals density functional (vdW-DF) to study the adsorption of graphene on Co, Ni, Pd, Ag, Au, Cu, Pt, and Al(111) surfaces. In contrast to the local-density approximation (LDA) which predicts relatively strong binding for Ni...

  1. Preschool physical activity and functional constipation: The generation r study

    NARCIS (Netherlands)

    Driessen, L.M.; Jong, J.C.K.D.; Wijtzes, A.; Vries, S.I. de; Jaddoe, V.W.V.; Hofman, A.; Raat, H.; Moll, H.A.

    2013-01-01

    OBJECTIVES:: Decreased physical activity levels in children may partly explain the rising prevalence of functional constipation in childhood. The aim of the present study, therefore, was to examine the association between physical activity and functional constipation during the preschool period. MET

  2. Development of a liquid xenon Compton telescope dedicated to functional medical imaging; Etude et developpement d'un telescope compton au xenon liquide dedie a l'imagerie medicale fonctionnelle

    Energy Technology Data Exchange (ETDEWEB)

    Grignon, C

    2007-12-15

    Functional imaging is a technique used to locate in three dimensions the position of a radiotracer previously injected in a patient. The two main modalities used for a clinical application to detect tumors, the SPECT and the PET, use solid scintillators as a detection medium. The objective of this thesis was to investigate the possibility of using liquid xenon in order to benefit from the intrinsic properties of this medium in functional imaging. The feasibility study of such a device has been performed by taking into account the technical difficulties specific to the liquid xenon. First of all, simulations of a liquid xenon PET has been performed using Monte-Carlo methods. The results obtained with a large liquid xenon volume are promising : we can expect a reduction of the injected activity of radiotracer, an improvement of the spatial resolution of the image and a parallax free camera. The second part of the thesis was focused on the development of a new concept of medical imaging, the three gamma imaging, based on the use of a new emitter: the 44 scandium. Associated to a classical PET camera, the Compton telescope is used to infer the incoming direction of the third gamma ray by triangulation. Therefore, it is possible to reconstruct the position of each emitter in three dimensions. This work convinced the scientific community to support the construction and characterization of a liquid xenon Compton telescope. The first camera dedicated to small animal imaging should then be operational in 2009. (author)

  3. Insomnia and endothelial function - the HUNT 3 fitness study.

    Directory of Open Access Journals (Sweden)

    Linn B Strand

    Full Text Available BACKGROUND: Insomnia is associated with increased risk of coronary heart disease (CHD, but the underlying mechanisms are not understood. To our knowledge, no previous studies have examined insomnia in relation to endothelial function, an indicator of preclinical atherosclerosis. Our aim was to assess the association of insomnia with endothelial function in a large population based study of healthy individuals. METHODS: A total of 4 739 participants free from known cardiovascular or pulmonary diseases, cancer, and sarcoidosis, and who were not using antihypertensive medication were included in the study. They reported how often they had experienced difficulties falling asleep at night, repeated awakenings during the night, early awakenings without being able to go back to sleep, and daytime sleepiness. Endothelial function was measured by flow mediated dilation (FMD derived from the brachial artery. RESULTS: We found no consistent association between the insomnia symptoms and endothelial function in multiadjusted models, but individual insomnia symptoms may be related to endothelial function. Among women who reported early awakenings, endothelial function may be lower than in women without this symptom (p = 0.03. CONCLUSIONS: This study provided no evidence that endothelial function, an early indicator of atherosclerosis, is an important linking factor between insomnia and CHD. Further studies are needed to explore the complex interrelation between sleep and cardiovascular pathology.

  4. Bioconcentration of the anionic surfactant linear alkylbenzene sulfonate (LAS) in the marine shrimp Palaemonetes varians: a radiotracer study.

    Science.gov (United States)

    Renaud, Florent; Warnau, Michel; Oberhänsli, François; Teyssié, Jean-Louis; Temara, Ali; Rouleau, Claude; Metian, Marc

    2014-08-15

    Uptake and depuration kinetics of dissolved [(14)C]C₁₂-6-linear alkylbenzene sulfonate (LAS) were determined in the shrimp Palaemonetes varians using environmentally relevant exposure concentration. The shrimp concentrated LAS from seawater with a mean BCF value of 120 L kg(-1) after a 7-day exposure. Uptake biokinetics were best described by a saturation model, with an estimated BCFss, of 159 ± 34 L kg(-1), reached after 11.5 days. Shrimp weight influenced significantly BCF value with smaller individuals presenting higher affinity to LAS. To the light of a whole body autoradiography, major accumulation of LAS occurred in the cephalothorax circulatory system (gills, heart, hepatopancreas) and ocular peduncle, but not in the flesh, limiting potential transfer to human consumers. LAS depuration rate constant value of the shrimp was 1.18 ± 0.08 d(-1) leading to less than 1% of remaining LAS in its tissues after 8 days of depuration.

  5. Functional brain imaging studies on specificity of meridian and acupoints

    Institute of Scientific and Technical Information of China (English)

    Xuezhi Li; Xuguang Liu; Fanrong Liang

    2008-01-01

    At present,the specificity of meridians and acupoints has been studied using functional brain imaging techniques from many standpoints.including meridians,acupoints,and sham acupoints,as well as different meridians and acupoints,coordination of acupoints,and factors influencing meridian and acupoint specificity.Preliminary experimental data have demonstrated that acupuncture at meridians and acupoints is specific with regard to brain neural information.However,research findings are contradictory,which may be related to brain functional complexity,resolution of functional brain imaging techniques,and experimental design.Future studies should further improve study method,and should strictly control experimental conditions to better analyze experimental data and acquire more beneficial data.Because of its many advantages.the functional brain imaging technique is a promising method for studying meridian and acupoint specificity.

  6. The study of functional parameter of the electric coal brushes

    Directory of Open Access Journals (Sweden)

    Claudia Staşac

    2008-05-01

    Full Text Available These paper present a study about the analyzeof the functional parameters of the electrical coal brush.The analyze was made with an experimental device, andthe results was prelucrate in MathCAD software.

  7. Yoga in male sexual functioning: a noncompararive pilot study.

    Science.gov (United States)

    Dhikav, Vikas; Karmarkar, Girish; Verma, Myank; Gupta, Ruchi; Gupta, Supriya; Mittal, Deeksha; Anand, Kuljeet

    2010-10-01

    Yoga is practiced both in developing and developed countries. Many patients and yoga protagonists claim that it is useful in improving sexual functions and treating sexual disorders. We wanted to study the effect of yoga on male sexual functioning. We studied 65 males (age range= 24-60 years, average age=40±8.26 years) who were enrolled in a yoga camp and administered a known questionnaire, i.e., Male Sexual Quotient (MSQ) before and after 12 weeks session of yoga. MSQ scores before and after yoga sessions. It was found that after the completion of yoga sessions, the sexual functions scores were significantly improved (Pfunctions as studied by MSQ (desire, intercourse satisfaction, performance, confidence, partner synchronization, erection, ejaculatory control, orgasm). Yoga appears to be an effective method of improving all domains of sexual functions in men as studied by MSQ. © 2010 International Society for Sexual Medicine.

  8. Language networks in children: Evidence from functional MRI studies

    OpenAIRE

    2009-01-01

    We review functional MRI and other neuroimaging studies of language skills in children from infancy to adulthood. These studies show developmental changes in the networks of brain regions supporting language, which can be affected by brain injuries or neurological disorders. Particular aspects of language rely on networks that lateralize to the dominant hemisphere; others rely on bilateral or non-dominant mechanisms. Multiple fMRI tasks for pediatric patients characterize functional brain reo...

  9. Iterative reconstruction of SiPM light response functions in a square-shaped compact gamma camera

    CERN Document Server

    Morozov, A; Marcos, J; Martins, R; Pereira, L; Solovov, V; Chepel, V

    2016-01-01

    Compact gamma cameras with a square-shaped monolithic scintillator crystal and an array of silicon photomultipliers (SiPMs) are actively being developed for applications in areas such as small animal imaging, cancer diagnostics and radiotracer guided surgery. Statistical methods of position reconstruction, which are potentially superior to the traditional centroid method, require accurate knowledge of the spatial response of each photomultiplier. Using both Monte Carlo simulations and experimental data obtained with a camera prototype, we show that the spatial response of all photomultipliers (light response functions) can be parameterized with axially symmetric functions obtained iteratively from flood field irradiation data. The study was performed with a camera prototype equipped with a 30 x 30 x 2 mm3 LYSO crystal and an 8 x 8 array of SiPMs for 140 keV gamma rays. The simulations demonstrate that the images, reconstructed with the maximum likelihood method using the response obtained with the iterative a...

  10. Pain perception and hypnosis: findings from recent functional neuroimaging studies.

    Science.gov (United States)

    Del Casale, Antonio; Ferracuti, Stefano; Rapinesi, Chiara; Serata, Daniele; Caltagirone, Saverio Simone; Savoja, Valeria; Piacentino, Daria; Callovini, Gemma; Manfredi, Giovanni; Sani, Gabriele; Kotzalidis, Georgios D; Girardi, Paolo

    2015-01-01

    Hypnosis modulates pain perception and tolerance by affecting cortical and subcortical activity in brain regions involved in these processes. By reviewing functional neuroimaging studies focusing on pain perception under hypnosis, the authors aimed to identify brain activation-deactivation patterns occurring in hypnosis-modulated pain conditions. Different changes in brain functionality occurred throughout all components of the pain network and other brain areas. The anterior cingulate cortex appears to be central in modulating pain circuitry activity under hypnosis. Most studies also showed that the neural functions of the prefrontal, insular, and somatosensory cortices are consistently modified during hypnosis-modulated pain conditions. Functional neuroimaging studies support the clinical use of hypnosis in the management of pain conditions.

  11. Relationship between functional connectivity and motor function assessment in stroke patients with hemiplegia: a resting-state functional MRI study

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ye; Wang, Li; Zhang, Jingna; Sang, Linqiong; Li, Pengyue; Qiu, Mingguo [Third Military Medical University, Department of Medical Imaging, College of Biomedical Engineering, Chongqing (China); Liu, Hongliang; Yan, Rubing [Third Military Medical University, Department of Rehabilitation, Southwest Hospital, Chongqing (China); Yang, Jun; Wang, Jian [Third Military Medical University, Department of Radiology, Southwest Hospital, Chongqing (China)

    2016-05-15

    Resting-state functional magnetic resonance imaging (fMRI) has been used to examine the brain mechanisms of stroke patients with hemiplegia, but the relationship between functional connectivity (FC) and treatment-induced motor function recovery has not yet been fully investigated. This study aimed to identify the brain FC changes in stroke patients and study the relationship between FC and motor function assessment using the resting-state fMRI. Seventeen stroke patients with hemiplegia and fifteen healthy control subjects (HCSs) were recruited in this study. We compared the FC between the ipsilesional primary motor cortex (M1) and the whole brain of the patients with the FC of the HCSs and studied the FC changes in the patients before and after conventional rehabilitation and motor imagery therapy. Additionally, correlations between the FC change and motor function of the patients were studied. Compared to the HCSs, the FC in the patient group was significantly increased between the ipsilesional M1 and the ipsilesional inferior parietal cortex, frontal gyrus, supplementary motor area (SMA), and contralesional angular and decreased between the ipsilesional M1 and bilateral M1. After the treatment, the FC between the ipsilesional M1 and contralesional M1 increased while the FC between the ipsilesional M1 and ipsilesional SMA and paracentral lobule decreased. A statistically significant correlation was found between the FC change in the bilateral M1 and the Fugl-Meyer assessment (FMA) score change. Our results revealed an abnormal motor network after stroke and suggested that the FC could serve as a biomarker of motor function recovery in stroke patients with hemiplegia. (orig.)

  12. Wave-function and density functional theory studies of dihydrogen complexes

    CERN Document Server

    Fabiano, E; Della Sala, F

    2014-01-01

    We performed a benchmark study on a series of dihydrogen bond complexes and constructed a set of reference bond distances and interaction energies. The test set was employed to assess the performance of several wave-function correlated and density functional theory methods. We found that second-order correlation methods describe relatively well the dihydrogen complexes. However, for high accuracy inclusion of triple contributions is important. On the other hand, none of the considered density functional methods can simultaneously yield accurate bond lengths and interaction energies. However, we found that improved results can be obtained by the inclusion of non-local exchange contributions.

  13. Early development of executive functions: a differential study

    Directory of Open Access Journals (Sweden)

    Sylvia Sastre-Riba

    2015-05-01

    Full Text Available The ontogeny of executive functions is essential in explaining differential and normative developmental trends. Executive functions must be studied from an early age given their consequential effects on mental flexibility, monitoring information, planning, and cognitive control. We propose a differential study in alternative developmental courses through observing typical babies, Down syndrome babies, and babies with risk-factors at birth (due to low weight or to congenital hypothyroidism. Applymg Systematic Observational Methodology, spontaneous babies' activity was registered. The results indicated that: a Typical babies showed better shifting and action flexibility in order to obtain a goal, thus better results; b Among the higher risk-babies, the lower efficacy in executive functioning was observed in underweight babies. Those with hypothyroidism were more in line with the typical babies; c Underweight babies showed a good level of combining actions but they obtained inferior results; d Down syndrome babies displayed more executive functioning difficulty, lower flexibility, high perseveration and less error detection.

  14. COMPARATIVE STUDY OF PULMONARY FUNCTION IN DIFFERENT TYPES OF SMOKERS

    Directory of Open Access Journals (Sweden)

    Abdul Majeed

    2015-12-01

    Full Text Available OBJECTIVES The aim and objective of this study is to compare the pulmonary function variables with the help of spirometer among beedi smokers, cigarette smokers and subjects who smoked both beedi and cigarette. BACKGROUND Smoking is a major public health problem and a major cause of many preventable diseases and premature deaths all over the world. Pulmonary function variables will differ based on the type of smoking i.e. Beedi smokers, cigarette smokers, subjects who smoked both beedi and cigarette. METHODS Cross sectional study done on 90 male smokers attending the Pulmonary Outpatient Department of Sri Ramachandra Medical College and Hospital. Spirometry was done to assess the pulmonary function. CONCLUSION Pulmonary function values showed significant reduction in beedi smokers than people who smoke both beedi and cigarette, followed by subjects who smoked cigarette alone.

  15. Pulmonary function studies in young healthy Malaysians of Kelantan, Malaysia

    OpenAIRE

    Bandyopadhyay, Amit

    2011-01-01

    Background & objectives: Pulmonary function tests have been evolved as clinical tools in diagnosis, management and follow up of respiratory diseases as it provides objective information about the status of an individual's respiratory system. The present study was aimed to evaluate pulmonary function among the male and female young Kelantanese Malaysians of Kota Bharu, Malaysia, and to compare the data with other populations. Methods: A total of 128 (64 males, 64 females) non-smoking healthy y...

  16. The Application of textual function in Of Studies

    Institute of Scientific and Technical Information of China (English)

    余硕

    2016-01-01

    Of Studies by Francis Bacon is a classic. It has been widespread since it was published. This paper probes into making a comprehensive description of the essay's textual meaning so as to finding out its application in Of Studies and verify the practicality of functional grammar in this essay.

  17. Common trajectories of physical functioning in the doetinchem cohort study

    NARCIS (Netherlands)

    Rooth, Vera; Van Oostrom, Sandra H.; Deeg, Dorly J H; Monique Verschuren, W. M.; Picavet, H. Susan J

    2016-01-01

    Purpose: To describe common trajectories of physical functioning and their determinants among an adult cohort, followed over a period of 15 years. Methods: The study sample consisted of 4,123 participants (initial ages 26-70 years) from the Doetinchem Cohort Study, who participated in three or four

  18. Appearance Investment and Everyday Interpersonal Functioning: An Experience Sampling Study

    Science.gov (United States)

    Forand, Nicholas R.; Gunthert, Kathleen C.; German, Ramaris E.; Wenze, Susan J.

    2010-01-01

    Several studies have shown that body satisfaction affects interpersonal functioning. However, few have studied the specific interpersonal correlates of another important body image dimension, appearance investment--that is, the importance a woman places on appearance. We used an experience sampling design with PDA (personal digital assistant)…

  19. A review of functional imaging studies on category-specificity

    DEFF Research Database (Denmark)

    Gerlach, Christian

    2007-01-01

    A review of 20 functional imaging studies that compared visual processing of natural objects and artefacts in normal subjects is presented. The studies included fulfilled three criteria: (i) they used pictures as stimuli, (ii) they were based on direct contrasts between categories, and (iii) they...

  20. Axial dispersion, holdup and slip velocity of dispersed phase in a pulsed sieve plate extraction column by radiotracer residence time distribution analysis

    Energy Technology Data Exchange (ETDEWEB)

    Din, Ghiyas Ud [Department of Nuclear Engineering, Pakistan Institute of Engineering and Applied Sciences (PIEAS), P.O. Nilore, Islamabad (Pakistan); Isotope Applications Division, Pakistan Institute of Nuclear Science and Technology (PINSTECH), P.O. Nilore, Islamabad (Pakistan)], E-mail: fac192@pieas.edu.pk; Chughtai, Imran Rafiq; Inayat, Mansoor Hameed [Department of Chemical and Materials Engineering, Pakistan Institute of Engineering and Applied Sciences (PIEAS), P.O. Nilore, Islamabad (Pakistan); Khan, Iqbal Hussain [Isotope Applications Division, Pakistan Institute of Nuclear Science and Technology (PINSTECH), P.O. Nilore, Islamabad (Pakistan)

    2008-12-15

    Axial dispersion, holdup and slip velocity of dispersed phase have been investigated for a range of dispersed and continuous phase superficial velocities in a pulsed sieve plate extraction column using radiotracer residence time distribution (RTD) analysis. Axial dispersion model (ADM) was used to simulate the hydrodynamics of the system. It has been observed that increase in dispersed phase superficial velocity results in a decrease in its axial dispersion and increase in its slip velocity while its holdup increases till a maximum asymptotic value is achieved. An increase in superficial velocity of continuous phase increases the axial dispersion and holdup of dispersed phase until a maximum value is obtained, while slip velocity of dispersed phase is found to decrease in the beginning and then it increases with increase in superficial velocity of continuous phase.

  1. Inappropriate cervical injection of radiotracer for sentinel node mapping in a uterine cervix cancer patient: importance of lymphoscintigraphy and blue dye injection

    Directory of Open Access Journals (Sweden)

    Sima Kadkhodayan

    2014-10-01

    Full Text Available Herein, we report a case of sentinel lymph node mapping in a uterine cervix cancer patient, referring to the nuclear medicine department of our institute. Lymphoscintigraphy images showed inappropriate intra‐cervical injection of radiotracer. Blue dye technique was applied for sentinel lymph node mapping, using intra‐cervical injection of methylene blue. Two blue/cold sentinel lymph nodes, with no pathological involvement, were intra‐operatively identified, and the patient was spared pelvic lymph node dissection. The present case underscores the importance of lymphoscintigraphy imaging in sentinel lymph node mapping and demonstrates the added value of blue dye injection in selected patients. It is suggested that preoperative lymphoscintigraphy imaging be considered as an integral part of sentinel lymph node mapping in surgical oncology. Detailed results of lymphoscintigraphy images should be provided for surgeons prior to surgery, and in case the sentinel lymph nodes are not visualized, use of blue dye for sentinel node mapping should be encouraged.

  2. Prospective cohort study of bowel function after robotic sacrocolpopexy.

    Science.gov (United States)

    Lewis, Christa; Salamon, Charbel; Priestley, Jennifer L; Gurshumov, Emil; Culligan, Patrick

    2014-01-01

    This study aimed to determine bowel function changes 12 months after robotic sacrocolpopexy. We performed a single-center prospective cohort study evaluating bowel function 12 months after robotic sacrocolpopexy between 2007 and 2011. Bowel function symptoms were measured by the Colorectal-Anal Distress Inventory, Short Form 8 (CRADI-8). Specific impacts on quality of life with regard to bowel function were evaluated using the Colorectal-Anal Impact Questionnaire, Short Form 7 (CRAIQ-7). "Splinting to defecate" was defined as any positive response to question 4 of the Pelvic Floor Distress Inventory-20 which reads, "do you ever have to push on the vagina or around the rectum to have or complete a bowel movement?." Lastly, patients were grouped according to perineorrhaphy versus no perineorrhaphy and bowel function scores were examined. Of 423 consecutive patients who underwent robotic sacrocolpopexy at our institution, 393 (93%) completed a 12-month follow-up. Mean CRADI-8 scores at baseline and 12 months were 21.1 (20) and 7.3 (11), respectively (P Robotic sacrocolpopexy was associated with significant improvements in bowel function as measured by CRADI-8 as well as improvements in impact on quality of life as measured by CRAIQ-7.

  3. Pulmonary function studies in young healthy Malaysians of Kelantan, Malaysia.

    Science.gov (United States)

    Bandyopadhyay, Amit

    2011-11-01

    Pulmonary function tests have been evolved as clinical tools in diagnosis, management and follow up of respiratory diseases as it provides objective information about the status of an individual's respiratory system. The present study was aimed to evaluate pulmonary function among the male and female young Kelantanese Malaysians of Kota Bharu, Malaysia, and to compare the data with other populations. A total of 128 (64 males, 64 females) non-smoking healthy young subjects were randomly sampled for the study from the Kelantanese students' population of the University Sains Malaysia, Kota Bharu Campus, Kelantan, Malaysia. The study population (20-25 yr age group) had similar socio-economic background. Each subject filled up the ATS (1978) questionnaire to record their personal demographic data, health status and consent to participate in the study. Subjects with any history of pulmonary diseases were excluded from the study. The pulmonary function measurements exhibited significantly higher values among males than the females. FEV 1% did not show any significant inter-group variation probably because the parameter expresses FEV 1 as a percentage of FVC. FVC and FEV 1 exhibited significant correlations with body height and body mass among males whereas in the females exhibited significant correlation with body mass, body weight and also with age. FEV 1% exhibited significant correlation with body height and body mass among males and with body height in females. FEF 25-75% did not show any significant correlation except with body height among females. However, PEFR exhibited significant positive correlation with all the physical parameters except with age among the females. On the basis of the existence of significant correlation between different physical parameters and pulmonary function variables, simple and multiple regression norms have been computed. From the present investigation it can be concluded that Kelantanese Malaysian youths have normal range of

  4. Study on Left Ventricular Diastolic Function under Different Left Ventricular Systolic Function

    Institute of Scientific and Technical Information of China (English)

    刘金来; SAID Mohmmed Abdalla; 王庆慧; 张成喜; 陈璘; 张燕玉

    2002-01-01

    Objectives Assessment of diastolic function is vital to impart information relevant to patients' cardiac functional class, diagnosis and management. We sought to investigate diastolic function under normal systolic function and systolic dysfunction and pseudonormalized phenomena.Methods 36 normal subjects( Group Ⅰ), 33 patients with coronary artery disease(CAD) (Group Ⅱ) and 74patients with essential hypertension(EH) (Group Ⅲ)were studied by color M-mode Doppler echocardiogrphy. The rate of propagation of peak early filling flowvelocity(Vp), time delay(TD) of the peak early fillingflow velocity from mitral tips to the apex, Vp/E andother parameters were measured by color M-modeDoppler echocardiography. Results Three groups had no statistical differences in gender, age and heart rate. There were significant differences of Vp, TD and Vp/E ratio between systolic dysfunction group and normal systolic function group. The result also showed significant differences in Vp, TD and Vp/E between pseudonormal group and control group( P < 0.01Conclusion The rate and time of propagation of peak early filling flow velocity (Vp, TD, Vp/E) by M -mode color Doppler echocardiography are more precise and reliable parameters to evaluate LV diastolic function by distinguishing pseudonormalized transmitral flow pattern.

  5. Diabetic hands: a study on strength and function.

    Science.gov (United States)

    de Carvalho e Silva, Fernanda; Jakimiu, Fernanda O; Skare, Thelma L

    2014-01-01

    To study hand strength and function in type 2 DM patients. We collected data on hand strength and function, disease duration, glycemic, creatinine and HbA1C levels, degree of pain and stiffness and physical examination in 100 DM patients comparing than with 100 hand osteoarthritis patients and 100 controls. DM patients had hand strength and function better than osteoarthritis patients and worse than controls. De Quervain tendonitis associated with hand strength (p=0.005); hand function associated with carpal tunnel syndrome (pQuervain tendinitis (p=0.006), HbA1C level (p=0.005), insulin use (p=0.030), disease duration (p=0.0006), pain (pQuervain tendinitis. Copyright © 2014 Diabetes India. Published by Elsevier Ltd. All rights reserved.

  6. Renal Function and Hemodynamic Study in Obese Zucker Rats

    OpenAIRE

    Park, Sung Kwang; Kang, Sung Kyew

    1995-01-01

    Objectives To investigate the renal function and hemodynamic changes in obesity and hyperinsulinemia which are characteristics of type II diabetes. Methods Studies were carried out in two groups of female Zucker rats. Group 1 rats were obese Zucker rats with hereditary insulin resistance. Group 2 rats were lean Zucker rats and served as controls. In comparison with lean Zucker rats, obese Zucker rats exhibited hyperinsulinemia but normoglycemia. Micropuncture studies and morphologic studies w...

  7. Autonomic nervous system function in patients with functional abdominal pain. An experimental study

    DEFF Research Database (Denmark)

    Jørgensen, L S; Christiansen, P; Raundahl, U

    1993-01-01

    Functional abdominal pain--that is, pain without demonstrable organic abnormalities--has often been associated with psychologic stress. The aim of the present study was to investigate whether sympathetic nervous system response to laboratory stress and basal parasympathetic neural activity were...

  8. Functional genomics studies on the innate immunity of disease vectors

    Institute of Scientific and Technical Information of China (English)

    Luke A. Baton; Lindsey Garver; Zhiyong Xi; George Dimopoulos

    2008-01-01

    The increasing availability of genome sequences and the development of high-throughput techniques for gene expression profiling and functional characterization are transforming the study of innate immunity and other areas of insect biology. Already,functional genomic approaches have enabled a quantum advance in the characterization of mosquito immune responses to malaria parasite infection, and similar high-throughput functional genomic studies of other vector-pathogen interactions can be expected in the near future. The application of microarray-based and other expression analyses provide genomewide transcriptional profiles that can be used to identify insect immune system components that are differentially regulated upon exposure to various classes of pathogens, including many important etiologic agents of human and animal diseases. The role of infection-responsive or other candidate immune genes identified through comparative genomic approaches can then be functionally characterized, either in vivo, for instance in adult mosquitoes, or in vitro using cell lines. In most insect vectors of human pathogens, germ-line transgenesis is still technically difficult and maintenance of multiple transgenic lines logistically demanding.Consequently, transient RNA interference (RNAi)-mediated gene-silencing has rapidly become the method of choice for functional characterization of candidate innate immune genes. The powerful combination of transcriptional profiling in conjunction with assays using RNAi to determine gene function, and identify regulatory pathways, together with downstream cell biological approaches to determine protein localization and interactions,will continue to provide novel insights into the role of insect innate immunity in a variety of vector-pathogen interactions. Here we review advances in functional genomics studies of innate immunity in the insect disease vectors, over the past decade, with a particular focus on the Anopheles mosquito and its

  9. Deconstructing multivariate decoding for the study of brain function.

    Science.gov (United States)

    Hebart, Martin N; Baker, Chris I

    2017-08-04

    Multivariate decoding methods were developed originally as tools to enable accurate predictions in real-world applications. The realization that these methods can also be employed to study brain function has led to their widespread adoption in the neurosciences. However, prior to the rise of multivariate decoding, the study of brain function was firmly embedded in a statistical philosophy grounded on univariate methods of data analysis. In this way, multivariate decoding for brain interpretation grew out of two established frameworks: multivariate decoding for predictions in real-world applications, and classical univariate analysis based on the study and interpretation of brain activation. We argue that this led to two confusions, one reflecting a mixture of multivariate decoding for prediction or interpretation, and the other a mixture of the conceptual and statistical philosophies underlying multivariate decoding and classical univariate analysis. Here we attempt to systematically disambiguate multivariate decoding for the study of brain function from the frameworks it grew out of. After elaborating these confusions and their consequences, we describe six, often unappreciated, differences between classical univariate analysis and multivariate decoding. We then focus on how the common interpretation of what is signal and noise changes in multivariate decoding. Finally, we use four examples to illustrate where these confusions may impact the interpretation of neuroimaging data. We conclude with a discussion of potential strategies to help resolve these confusions in interpreting multivariate decoding results, including the potential departure from multivariate decoding methods for the study of brain function. Copyright © 2017. Published by Elsevier Inc.

  10. Sexual abuse predicts functional somatic symptoms : An adolescent population study

    NARCIS (Netherlands)

    Bonvanie, Irma J.; van Gils, Anne; Janssens, Karin A. M.; Rosmalen, Judith G. M.

    2015-01-01

    The main aim of this study was to investigate the effect of childhood sexual abuse on medically not well explained or functional somatic symptoms (FSSs) in adolescents. We hypothesized that sexual abuse predicts higher levels of FSSs and that anxiety and depression contribute to this relationship. I

  11. Sexual functioning of people with rheumatoid arthritis : a multicenter study

    NARCIS (Netherlands)

    van Berlo, W.T.M.; van de Wiel, H.B.M.; Taal, E.; Rasker, J.J.; Schultz, W.C.M.W.; van Rijswijk, M.H.

    2007-01-01

    The objective of this study is to compare men and women with rheumatoid arthritis (RA) to controls regarding sexual motivation, activity, satisfaction, and specific sexual problems, and to determine the correlation of physical aspects of the disease with sexual functioning. Questionnaire for screeni

  12. Executive function training in children with SLI: A pilot study

    NARCIS (Netherlands)

    Vugs, B.A.M.; Knoors, H.E.T.; Cuperus, J.M.; Hendriks, M.P.H.; Verhoeven, L.T.W.

    2017-01-01

    The aim of this study was to evaluate the effectiveness of a computer-based executive function (EF) training in children with specific language impairment (SLI). Ten children with SLI, ages 8 to 12 years, completed a 25-session training of visuospatial working memory, inhibition and cognitive

  13. Neural Basis of Tics: A Functional MRI Study

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2006-09-01

    Full Text Available Event-related functional MRI (fMRI was used to study the neural basis of spontaneous motor and vocal tics in 10 patients with Tourette syndrome, at the National Institute of Neurological Disorders and Stroke, Bethesda, MD.

  14. Sexual abuse predicts functional somatic symptoms : An adolescent population study

    NARCIS (Netherlands)

    Bonvanie, Irma J.; van Gils, Anne; Janssens, Karin A. M.; Rosmalen, Judith G. M.

    The main aim of this study was to investigate the effect of childhood sexual abuse on medically not well explained or functional somatic symptoms (FSSs) in adolescents. We hypothesized that sexual abuse predicts higher levels of FSSs and that anxiety and depression contribute to this relationship.

  15. Executive Function Training in Children with SLI: A Pilot Study

    Science.gov (United States)

    Vugs, Brigitte; Knoors, Harry; Cuperus, Juliane; Hendriks, Marc; Verhoeven, Ludo

    2017-01-01

    The aim of this study was to evaluate the effectiveness of a computer-based executive function (EF) training in children with specific language impairment (SLI). Ten children with SLI, ages 8 to 12 years, completed a 25-session training of visuospatial working memory, inhibition and cognitive flexibility over a 6-week period. Treatment outcome was…

  16. A Qualitative Case Study: Teacher Perceptions of Executive Function

    Science.gov (United States)

    Reed, Stacey L. E.

    2016-01-01

    Executive function (EF) is becoming a more widely used term to explain student behaviors, yet research on EF in education is limited. This qualitative study addressed a gap in literature by examining teacher perceptions of students with EF deficits, as well as teacher preparedness and desire to learn more about EF. Perceptions of third grade,…

  17. Sexual functioning of people with rheumatoid arthritis: a multicenter study

    NARCIS (Netherlands)

    Berlo, van Willy T.M.; Wiel, van de Harry B.M.; Taal, Erik; Rasker, Johannes J.; Weijmar Schultz, Willibrord C.M.; Rijswijk, van Martin H.

    2007-01-01

    The objective of this study is to compare men and women with rheumatoid arthritis (RA) to controls regarding sexual motivation, activity, satisfaction, and specific sexual problems, and to determine the correlation of physical aspects of the disease with sexual functioning. Questionnaire for screeni

  18. Investigator Bias in Urodynamic Studies for Functional Urinary Incontinence

    NARCIS (Netherlands)

    Bael, An; Verhulst, John; Lax, Hildegard; Hirche, Herbert; van Gool, Jan D.

    2009-01-01

    Purpose: In the setting of the European Bladder Dysfunction Study, a multi-center, randomized, controlled trial of treatment options for functional incontinence in children, we assessed the concordance between reported and reviewed urodynamic scores. Materials and Methods: A total of 97 children wit

  19. Functional Communication Training in Rett Syndrome: A Preliminary Study

    Science.gov (United States)

    Byiers, Breanne J.; Dimian, Adele; Symons, Frank J.

    2014-01-01

    Rett syndrome (RTT) is associated with a range of serious neurodevelopmental consequences including severe communicative impairments. Currently, no evidence-based communication interventions exist for the population (Sigafoos et al., 2009). The purpose of the current study was to examine the effectiveness of functional assessment (FA) and…

  20. Sexual abuse predicts functional somatic symptoms : An adolescent population study

    NARCIS (Netherlands)

    Bonvanie, Irma J.; van Gils, Anne; Janssens, Karin A. M.; Rosmalen, Judith G. M.

    2015-01-01

    The main aim of this study was to investigate the effect of childhood sexual abuse on medically not well explained or functional somatic symptoms (FSSs) in adolescents. We hypothesized that sexual abuse predicts higher levels of FSSs and that anxiety and depression contribute to this relationship. I

  1. Imaging tools to study pharmacology: functional MRI on small rodents

    Directory of Open Access Journals (Sweden)

    Elisabeth eJonckers

    2015-10-01

    Full Text Available Functional Magnetic Resonance Imaging (fMRI is an excellent tool to study the effect of pharmacological modulations on brain function in a non-invasive and longitudinal manner. We introduce several blood oxygenation level dependent (BOLD fMRI techniques, including resting state (rsfMRI, stimulus-evoked (st-fMRI, and pharmacological MRI (phMRI. Respectively, these techniques permit the assessment of functional connectivity during rest as well as brain activation triggered by sensory stimulation and/or a pharmacological challenge. The first part of this review describes the physiological basis of BOLD fMRI and the hemodynamic response on which the MRI contrast is based. Specific emphasis goes to possible effects of anaesthesia and the animal’s physiological conditions on neural activity and the hemodynamic response. The second part of this review describes applications of the aforementioned techniques in pharmacologically-induced, as well as in traumatic and transgenic disease models and illustrates how multiple fMRI methods can be applied successfully to evaluate different aspects of a specific disorder. For example, fMRI techniques can be used to pinpoint the neural substrate of a disease beyond previously defined hypothesis-driven regions-of-interest (ROIs. In addition, fMRI techniques allow one to dissect how specific modifications (e.g. treatment, lesion etc. modulate the functioning of specific brain areas (st-fMRI, phMRI and how functional connectivity (rsfMRI between several brain regions is affected, both in acute and extended time frames. Furthermore, fMRI techniques can be used to assess/explore the efficacy of novel treatments in depth, both in fundamental research as well as in preclinical settings. In conclusion, by describing several exemplary studies, we aim to highlight the advantages of functional MRI in exploring the acute and long-term effects of pharmacological substances and/or pathology on brain functioning along with

  2. Features and Functions of Journals: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Bambang Yudi Cahyono

    1997-01-01

    Full Text Available Abstract: This study is intended to describe the features and functions of journals written by EFL learners. The features described include the contents and organization of the journals. The functions examined in this study include sense of purpose and sense of audience in writing. The subjects of the study were students of the first semester who took English intensive course at the English Department of IKIP MALANG. The results of content analysis indicate that journals that the students write contain various themes. Analysis on paragraph organization indicates that paragraphs in the journals generally show adequate development. This study also shows that the student journals reflect sense of purpose and sense of audience in writing.

  3. The functionalities of mobile applications : case study: WeChat

    OpenAIRE

    Dai, Si; Zhang, Xin

    2015-01-01

    The objective of this thesis is to find out the functionalities of mobile application. And the purpose of this study is to make a research on WeChat’s functionalities. A native application and mobile web application are the two different types of mobile applications. When designers start to create an application, companies need to discuss which type of app is more suitable for business targets. Each has both pros and cons which influence companies’ choice. WeChat is a popular mobile applicati...

  4. Functional Connectivity Studies Of Patients With Auditory Verbal Hallucinations

    Directory of Open Access Journals (Sweden)

    Ralph E Hoffman

    2012-01-01

    Full Text Available Functional connectivity (FC studies of brain mechanisms leading to auditory verbal hallucinations (AVHs utilizing functional magnetic resonance imaging (fMRI data are reviewed. Initial FC studies utilized fMRI data collected during performance of various tasks, which suggested frontotemporal disconnection and/or source-monitoring.disturbances. Later FC studies have utilized resting (no-task fMRI data. These studies have produced a mixed picture of disconnection and hyperconnectivity involving different pathways associated with AVHs. Results of our most recent FC study of AVHs are reviewed in detail. This study suggests that the core mechanism producing AVHs involves not a single pathway, but a more complex functional loop. Components of this loop include Wernicke’s area and its right homologue, the left inferior frontal cortex, and the putamen. It is noteworthy that the putamen appears to play a critical role in the generation of spontaneous language, and in determining whether auditory stimuli are registered consciously as percepts. Excessive functional coordination linking this region with the Wernicke’s seed region in patients with schizophrenia could therefore generate an overabundance of potentially conscious language representations. In our model, intact FC in the other two legs of corticostriatal loop (Wernicke’s with left IFG, and left IFG with putamen appeared to allow this disturbance (common to schizophrenia overall to be expressed as a conscious hallucination of speech. Recommendations for future studies are discussed, including inclusion of multiple methodologies applied to the same subjects in order to compare and contrast different mechanistic hypotheses, utilizing EEG to better parse time-course of neural synchronization leading to AVHs, and ascertaining experiential subtypes of AVHs that may reflect distinct mechanisms.

  5. High functional load inhibits phonological contrast loss: a corpus study.

    Science.gov (United States)

    Wedel, Andrew; Kaplan, Abby; Jackson, Scott

    2013-08-01

    For nearly a century, linguists have suggested that diachronic merger is less likely between phonemes with a high functional load--that is, phonemes that distinguish many words in the language in question. However, limitations in data and computational power have made assessing this hypothesis difficult. Here we present the first larger-scale study of the functional load hypothesis, using data from sound changes in a diverse set of languages. Our results support the functional load hypothesis: phoneme pairs undergoing merger distinguish significantly fewer minimal pairs in the lexicon than unmerged phoneme pairs. Furthermore, we show that higher phoneme probability is positively correlated with merger, but that this effect is stronger for phonemes that distinguish no minimal pairs. Finally, within our dataset we find that minimal pair count and phoneme probability better predict merger than change in system entropy at the lexical or phoneme level.

  6. Monte Carlo studies of matrix theory correlation functions.

    Science.gov (United States)

    Hanada, Masanori; Nishimura, Jun; Sekino, Yasuhiro; Yoneya, Tamiaki

    2010-04-16

    We study correlation functions in (0+1)-dimensional maximally supersymmetric U(N) gauge theory, which represents the low-energy effective theory of D0-branes. In the large-N limit, the gauge-gravity duality predicts power-law behaviors in the infrared region for the two-point correlation functions of operators corresponding to supergravity modes. We evaluate such correlation functions on the gauge theory side by the Monte Carlo method. Clear power-law behaviors are observed at N=3, and the predicted exponents are confirmed consistently. Our results suggest that the agreement extends to the M-theory regime, where the supergravity analysis in 10 dimensions may not be justified a priori.

  7. Systolic and diastolic cardiac function in acromegaly. An echocardiographic study.

    Science.gov (United States)

    Galanti, G; Cappelli, B; Diricatti, G; Mininni, S; Vono, M C; Gensini, G F

    1996-01-01

    The aim of this study was to establish the existence of primary acromegalic cardiomyopathy different from the cardiovascular complications often associated with acromegaly. Thirty-four acromegalic patients, referred to our non-invasive laboratory and divided into two groups on the basis of the presence of hypertension, underwent echocardiographic studies. A control group of 34 subjects individually matched with the patients for age, sex, and blood pressure values was also studied. To evaluate cardiac function during exercise, the normotensive acromegalics, the control group, and a group of 9 athletes with left ventricular mass comparable to that of the acromegalic subjects underwent a handgrip test. Cardiac mass was increased in all patients; hypertensive patients had a greater increase than normotensive patients (144.9 +/- 38 vs 120.9 +/- 20.8 g/m, p cardiac hypertrophy caused by GH hyperincretion does not improve acromegalic heart activity: diastolic function, although normal at rest, appears deficient during isometric exercise.

  8. Cortical language activation in aphasia:a functional MRI study

    Institute of Scientific and Technical Information of China (English)

    徐晓俊; 张敏鸣; 商德胜; 汪启东; 罗本燕; 翁旭初

    2004-01-01

    Background Functional neuroimaging has been used in neurolinguistic research on normal subjects and on patients with brain damage. This study was designed to investigate the differences of the neural basis underlying language processing between normal subjects and aphasics.Methods Functional magnetic resonance imaging (fMRI) was used to map the language network in 6 normal subjects and 3 patients with aphasia who were in the stage of recovery from acute stroke. The participants performed a word generation task during multi-slice functional scanning for the measurement of signal change associated with regional neural activity induced by the task. Results In normal subjects, a distributed language network was activated. Activations were present in the frontal, temporal, parietal and occipital regions. In the patient group, however, no activation was detected in the left inferior frontal gyrus whether the patient had a lesion in the left frontal lobe or not. Two patients showed activations in some right hemisphere regions where no activation appeared in normal subjects. Conclusions fMRI with word generation task is feasible for evaluating language function in aphasic patients. Remote effect of focal lesion and functional redistribution or reorganisation can be found in aphasic patients.

  9. Executive function influences sedentary behavior: A longitudinal study

    Science.gov (United States)

    Loprinzi, Paul D.; Nooe, Allison

    2016-01-01

    Background: No study has evaluated the effects of executive function on follow-up sedentary behavior, which was this study’s purpose. Methods: A longitudinal design was employed among 18 young adult college students (Mage = 23.7 years; 88.9% female). Accelerometer-determined sedentary behavior and physical activity, along with executive function, were assessed at baseline. Approximately 8 weeks later, re-assessment of accelerometer-determined sedentary behavior and physical activity occurred. Executive function was assessed using the Parametric Go/No-Go (PGNG) computer task. From this, 2 primary executive function outcome parameters were evaluated, including the Simple Rule and Repeating Rule. Results: After adjusting for baseline sedentary behavior, age, gender, body mass index and baseline moderate-to-vigorous physical activity (MVPA), for every 25% increase in the number of correctly identified targets for the Repeating rule at the baseline assessment, participants engaged in 91.8 fewer minutes of sedentary behavior at the follow-up assessment (β = -91.8; 95% CI: -173.5, -10.0; P = 0.03). Results were unchanged when also adjusting for total baseline or follow-up physical activity. Conclusion: Greater executive function is associated with less follow-up sedentary behavior.

  10. Executive function influences sedentary behavior: A longitudinal study

    Directory of Open Access Journals (Sweden)

    Paul D. Loprinzi

    2016-10-01

    Full Text Available Background: No study has evaluated the effects of executive function on follow-up sedentary behavior, which was this study’s purpose. Methods: A longitudinal design was employed among 18 young adult college students (Mage = 23.7 years; 88.9% female. Accelerometer-determined sedentary behavior and physical activity, along with executive function, were assessed at baseline. Approximately 8 weeks later, re-assessment of accelerometer-determined sedentary behavior and physical activity occurred. Executive function was assessed using the Parametric Go/No-Go (PGNG computer task. From this, 2 primary executive function outcome parameters were evaluated, including the Simple Rule and Repeating Rule. Results: After adjusting for baseline sedentary behavior, age, gender, body mass index and baseline moderate-to-vigorous physical activity (MVPA, for every 25% increase in the number of correctly identified targets for the Repeating rule at the baseline assessment, participants engaged in 91.8 fewer minutes of sedentary behavior at the follow-up assessment (β = -91.8; 95% CI: -173.5, -10.0; P = 0.03. Results were unchanged when also adjusting for total baseline or follow-up physical activity. Conclusion: Greater executive function is associated with less follow-up sedentary behavior.

  11. Optimizing the mercury mass measurement in industrial electrolytic cells by the radio-tracer method at ININ; Optimizacion de la medicion de masa de mercurio en celdas electroliticas industriales por el metodo de radiotrazado en el ININ

    Energy Technology Data Exchange (ETDEWEB)

    Valle R, J.; Angeles C, A., E-mail: Ing.valle.r@hotmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2014-10-15

    One method used in the production of chlorine and sodium is the use of electrolytic cells for the separation of chlorine and sodium from the brine; the industries apply very intense electromagnetic fields in this process. The electrolytic cells use mercury as electrode. In a chlorine production plant inventories are determined by total amount of mercury in the plant annually, since mercury losses are large and a very important parameter is to control the mass of mercury for it is necessary to measure with great precision the losses made. There are several methods to determine the mass of mercury ranging from take samples and weigh, but this involves continuous interruption of the process creating downtimes which in turn represent economic losses giving a result delimiting productivity for the industrial sector. An alternative and attractive method is to use a radioactive tracer whose principle has a similar behavior to study objective. The inert mercury has to be neutron activated in a nuclear reactor to having the characteristics of a tracer; the result makes one of the isotopes of mercury. The tracer is transported taking into account the recommendations of the Comision Nacional de Seguridad Nuclear y Salvaguardias (Mexico), then it is injected into the electrolytic cells mixing with the mercury in the system. By a relative radioactivity measurement and one sample by gamma spectrometry per interest cell, the mass of mercury without stopping the process is obtained. For optimal use of radio-tracer method must be taken into account as important features: irradiation time of mercury, counting conditions, vial geometry, sample volume, sample cells, mixing time and half-life of the tracer. (Author)

  12. Considerations for Resting State Functional MRI and Functional Connectivity Studies in Rodents

    Directory of Open Access Journals (Sweden)

    Wen-Ju ePan

    2015-08-01

    Full Text Available Resting state functional MRI (rs-fMRI and functional connectivity mapping have become widely used tools in the human neuroimaging community and their use is rapidly spreading into the realm of rodent research as well. One of the many attractive features of rs-fMRI is that it is readily translatable from humans to animals and back again. Changes in functional connectivity observed in human studies can be followed by more invasive animal experiments to determine the neurophysiological basis for the alterations, while exploratory work in animal models can identify possible biomarkers for further investigation in human studies. These types of interwoven human and animal experiments have a potentially large impact on neuroscience and clinical practice. However, impediments exist to the optimal application of rs-fMRI in small animals, some similar to those encountered in humans and some quite different. In this review we identify the most prominent of these barriers, discuss differences between rs-fMRI in rodents and in humans, highlight best practices for animal studies, and review selected applications of rs-fMRI in rodents. Our goal is to facilitate the integration of human and animal work to the benefit of both fields.

  13. A Study on the Design of Electronic SAMG Functional Modules

    Energy Technology Data Exchange (ETDEWEB)

    Park, S. H.; Kim, J. H.; Ahn, K. I. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    This paper describes a study on the design of e-SAMG functional modules. A study of for the design of e-SAMG was introduced. During an emergency status of a severe accident, the items for the functional module during a rapid and exact action are surveyed. The results are being implemented in e-SAMG. The operators can be supported through the use of e-SAMG. Based on the design of functional modules, the implementation will be accelerated and the refined design can also be applied. As a part of the Ministry of Science, ICT and future Planning (MSIP) Project, we at KAERI are developing electronic SAMG (e-SAMG, severe accident mitigation guideline) for general SAMG for nuclear power plants. Due to computerized trends, various efforts related to computer systems have been carried out for safety systems in nuclear power plants. In particular, since the Fukushima accident, unexpected accidents or extreme damages have become a concern. With this status, a rapid and exact confrontation such as a computerized attempt in SAMG has been tried. To develop an electronic SAMG, based on an analysis of the general SAMG, the architecture of e-SAMG was founded. The functional modules occupy important parts in the e-SAMG.

  14. Difficulties in academic writing and cognitive functions: review of studies

    Directory of Open Access Journals (Sweden)

    William Rodrigo Avendaño Castro

    2017-03-01

    Full Text Available The objective of this article is to analyze some of the difficulties of academic writing at postgraduate level, reported in certain studies within the framework of the cognitive functions concept developed by Reuven Feuerstein and other works, which allow to evidence the possible relationship between these two phenomena. To do this, we explored the conceptual framework of cognitive functions and mental operations, based on the theory of Feuerstein, et al. (1994; later, it was performed a synthesis of the difficulties described by Carlino (2007, Slafer (2009 and Hernández (2009; finally, it was established evidence of the relationship between cognitive functions and difficulties in academic writing. The results show that the different difficulties evidenced in the writing processes at postgraduate level have their source in the cognitive deficits presented in each phase of the mental act (entry, elaboration and output. It is concluded that the difficulties in academic writing recorded in the studies have a close link with cognitive functions of the elaboration and output stages of thought, even though they are only associated with the input phase.

  15. [Cerebral vasoreactivity and functional response in stroke: a study with functional MR].

    Science.gov (United States)

    Piñeiro, R; Matthews, P M

    Lacunar infarcts are usually associated with anatomical and possibly functional changes in the walls of small blood vessels (penetrating arteries). The functional effect varies and is accompanied by cerebral adaptive/reorganizational changes. BOLD contrast, originated in the microvasculature (especially with ultra high magnetic fields) depends, in the end, on haemodynamic changes and is useful for exploring patterns of cerebral activation using fMR. To compare the temporal behaviour of the BOLD signal and the distribution of activation between a group of patients with no functional sequelae following a stroke and a control group, by using fMR at 3T. The stroke group showed a smaller number of voxels activated, but this was not statistically significant. The patterns of activation, size of the sensor motor area (SM or ASM) and index of laterality were similar in both groups. In SM the BOLD response was 85% slower (pstroke group, which were insufficient to produce reorganizational/adaptive changes or by the great variety of responses. The temporal response of the BOLD response was different in the stroke group, probably as a result of the alteration in the haemodynamic response in relation to the underlying processes which damage the functional properties of the vascular wall. This difference in the BOLD response should be interpreted with caution, and borne in mind when interpreting activation in persons with vascular pathology. Further studies are necessary for better understanding of its significance.

  16. [sup 99m]TC-MAG[sub 3] renal function scintigraphy and captopril in the diagnosis of renovascular hypertension. [sup 99m]Tc-MAG[sub 3]-Nierenfunktionsszintigraphie ohne und mit Captopril zur Diagnostik der renovaskulaeren Hypertonie

    Energy Technology Data Exchange (ETDEWEB)

    Piepenburg, R. (Mainz Univ. (Germany). Klinik mit Poliklinik fuer Nuklearmedizin); Bockisch, A. (Mainz Univ. (Germany). Klinik mit Poliklinik fuer Nuklearmedizin); Andreas, J. (Mainz Univ. (Germany). Klinik mit Poliklinik fuer Nuklearmedizin); Dueber, C. (Mainz Univ. (Germany). Klinik fuer Roentgendiagnostik); Kann, P. (Mainz Univ. (Germany). 3. Medizinische Klinik und Poliklinik, Innere Medizin und Endokrinologie); Maier, G. (Mainz Univ. (Germany). Klinik mit Poliklinik fuer Nuklearmedizin); Hahn, K. (Mainz Univ. (Germany). Klinik mit Poliklinik fuer Nuklearmedizin)

    1993-08-01

    In this study, the diagnostic value of renal function scintigraphy performed both without and with ACE inhibition has been evaluated using the new radiopharmaceutical [sup 99m]Tc-MAG[sub 3]. In cases of decompensated renal artery stenoses, the typical scan finding with this tubular excreted agent was shown to be a distinct parenchymal nuclide retention in combination with a delayed appearance of the radiotracer in the pelvic system. Using this criterion in 43 patients with suspected renovascular hypertension, sensitivity and specificity were 89 and 88%, respectively. Bilateral positive findings were non-specific; excluding them from the study, specificity increased to 100%. In renal insufficiency, captopril scans seem to be of reduced diagnostic value. Summarising our experiences, renal function scintigraphy using [sup 99m]Tc-MAG[sub 3] without and with captopril was proved to be a reliable non-invasive method to detect or exclude haemodynamically relevant renal artery stenosis. (orig.)

  17. Functional assessment of sodium chloride cotransporter NCC mutants in polarized mammalian epithelial cells

    DEFF Research Database (Denmark)

    Rosenbaek, Lena L; Rizzo, Federica; MacAulay, Nanna

    2017-01-01

    oocytes. Here, we developed the use of polarized Madin-Darby canine kidney type I (MDCKI) mammalian epithelial cell lines with tetracycline-inducible human NCC expression to study NCC activity and membrane abundance in the same system. In radiotracer assays, induced cells grown on filters had robust...

  18. Functional Magnetic Resonance Imaging and Functional Near-Infrared Spectroscopy: Insights from Combined Recording Studies

    Directory of Open Access Journals (Sweden)

    Vanessa Scarapicchia

    2017-08-01

    Full Text Available Although blood oxygen level dependent (BOLD functional magnetic resonance imaging (fMRI is a widely available, non-invasive technique that offers excellent spatial resolution, it remains limited by practical constraints imposed by the scanner environment. More recently, functional near infrared spectroscopy (fNIRS has emerged as an alternative hemodynamic-based approach that possesses a number of strengths where fMRI is limited, most notably in portability and higher tolerance for motion. To date, fNIRS has shown promise in its ability to shed light on the functioning of the human brain in populations and contexts previously inaccessible to fMRI. Notable contributions include infant neuroimaging studies and studies examining full-body behaviors, such as exercise. However, much like fMRI, fNIRS has technical constraints that have limited its application to clinical settings, including a lower spatial resolution and limited depth of recording. Thus, by combining fMRI and fNIRS in such a way that the two methods complement each other, a multimodal imaging approach may allow for more complex research paradigms than is feasible with either technique alone. In light of these issues, the purpose of the current review is to: (1 provide an overview of fMRI and fNIRS and their associated strengths and limitations; (2 review existing combined fMRI-fNIRS recording studies; and (3 discuss how their combined use in future research practices may aid in advancing modern investigations of human brain function.

  19. A study on the quantitative evaluation of skin barrier function

    Science.gov (United States)

    Maruyama, Tomomi; Kabetani, Yasuhiro; Kido, Michiko; Yamada, Kenji; Oikaze, Hirotoshi; Takechi, Yohei; Furuta, Tomotaka; Ishii, Shoichi; Katayama, Haruna; Jeong, Hieyong; Ohno, Yuko

    2015-03-01

    We propose a quantitative evaluation method of skin barrier function using Optical Coherence Microscopy system (OCM system) with coherency of near-infrared light. There are a lot of skin problems such as itching, irritation and so on. It has been recognized skin problems are caused by impairment of skin barrier function, which prevents damage from various external stimuli and loss of water. To evaluate skin barrier function, it is a common strategy that they observe skin surface and ask patients about their skin condition. The methods are subjective judgements and they are influenced by difference of experience of persons. Furthermore, microscopy has been used to observe inner structure of the skin in detail, and in vitro measurements like microscopy requires tissue sampling. On the other hand, it is necessary to assess objectively skin barrier function by quantitative evaluation method. In addition, non-invasive and nondestructive measuring method and examination changes over time are needed. Therefore, in vivo measurements are crucial for evaluating skin barrier function. In this study, we evaluate changes of stratum corneum structure which is important for evaluating skin barrier function by comparing water-penetrated skin with normal skin using a system with coherency of near-infrared light. Proposed method can obtain in vivo 3D images of inner structure of body tissue, which is non-invasive and non-destructive measuring method. We formulate changes of skin ultrastructure after water penetration. Finally, we evaluate the limit of performance of the OCM system in this work in order to discuss how to improve the OCM system.

  20. Structure-Function Studies on the Prolactin Receptor

    DEFF Research Database (Denmark)

    Haxholm, Gitte Wolfsberg

    the PRLR-ICD and the ICD of the related growth hormone receptor (GHR). We showed that both ICDs were intrinsically disordered throughout their entire lengths and that they associated with lipids characteristic of the inner plasma membrane leaflet through conserved motifs, implicating the membrane......Class 1 Cytokine receptors are involved in important biological functions mediated through complex networks of intracellular signaling. However, the molecular details of how signaling is regulated are poorly understood. One of the primary reasons for this limited knowledge is the lack of structural...... information on the intracellular domains (ICDs) of these receptors. The overall aim of this study was to obtain an improved understanding of cytokine receptor signaling through structure-function studies on the prolactin receptor (PRLR). The primary focus of this thesis was to structurally characterize...

  1. Structure-Function Studies on the Prolactin Receptor

    DEFF Research Database (Denmark)

    Haxholm, Gitte Wolfsberg

    Class 1 Cytokine receptors are involved in important biological functions mediated through complex networks of intracellular signaling. However, the molecular details of how signaling is regulated are poorly understood. One of the primary reasons for this limited knowledge is the lack of structural...... information on the intracellular domains (ICDs) of these receptors. The overall aim of this study was to obtain an improved understanding of cytokine receptor signaling through structure-function studies on the prolactin receptor (PRLR). The primary focus of this thesis was to structurally characterize...... the PRLR-ICD and the ICD of the related growth hormone receptor (GHR). We showed that both ICDs were intrinsically disordered throughout their entire lengths and that they associated with lipids characteristic of the inner plasma membrane leaflet through conserved motifs, implicating the membrane...

  2. 整合素受体靶向显像诊断乳腺癌溶骨性转移%Imaging of osteolytic bone metastasis from breast cancer with new integrin αvβ3 receptor targeted radiotracer

    Institute of Scientific and Technical Information of China (English)

    邵国强; 赵有财; 崔璨; 梁凯; 孙晋; 杨瑞; 王峰

    2015-01-01

    Objective To investigate the value of integrin αvβ3 targeted micro positron emission tomography (microPET)/CT imaging with 68 Ca-1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid-arginine-glycine-aspartate peptide dimer (68 Ga-DOTA-RGD2) as radiotracer for the detection of breast cancer osteolytic bone metastases.Methods 68 Ga-DOTA-RGD2 was prepared via one-step method at 100 ℃ for 15 min.Animal model with parathyroid hormone (PTH)-induced osteolysis in the calvarium was established and served as PTH group (BP).Biodistribution study of 68 Ga-DOTA-RGD2 was carried out in BP.Integrin receptor block study was done with pre-injection of high dose of DOTA-RGD2.68Ga-DOTA-RGD2 and 18F-NaF micmPET/CT imaging were perfromed respectively.Breast cancer osteolyic bone metastases was established via intrcardial injection of breast cancer cells.68 Ga-DOTA-RGD2 microPET/CT imaging were perfromed for the detection of breast cancer osetolytic bone metastases.Animals were sarcrificed and bone lesions were harvested for pathological examination.Results 68 Ga-DOTA-RGD2 was stable in vitro and its radiopurity was as high as (96.4 ± 2.1) % 3 h after its preparation.Its blood elimination was fast while its uptake by the liver and kidneys were relativelylow.It was discharged soon after its intravenous injection.In the BP group,regional uptake of 68 Ga-DOTA-RGD2 in osteolytic lesion of calvarium (% ID/g) reached peak (5.14 ±0.65) 60 min after tail vein injection.It was significantly more than that in BC group (2.06 ±0.35,t =7.81,P <0.05).Bone radiotracer uptake ratio of osteolytic lesion to normal calvrium (O/N) was compared based microPET/CT imaging.Bone O/N of 68Ga-DOTA-RGD2 was (6.10 ± 0.97),significantly greater than that of 18F-NaF (1.20 ±0.33,t =10.17,P <0.05).68Ga-DOTA-RGD2 microPET/CT imaging was able to demonstrate the ostelytic bone metastasis in calvarium,thoracic vertebrae and lung metastasis.They were confirmed by pathology results.Conclusion 68 Ga

  3. Buckled graphene: A model study based on density functional theory

    KAUST Repository

    Khan, Mohammad A.

    2010-09-01

    We make use of ab initio calculations within density functional theory to investigate the influence of buckling on the electronic structure of single layer graphene. Our systematic study addresses a wide range of bond length and bond angle variations in order to obtain insights into the energy scale associated with the formation of ripples in a graphene sheet. © 2010 Elsevier B.V. All rights reserved.

  4. Density functional theory studies of transition metal nanoparticles in catalysis

    DEFF Research Database (Denmark)

    Greeley, Jeffrey Philip; Rankin, Rees; Zeng, Zhenhua

    2013-01-01

    Periodic Density Functional Theory calculations are capable of providing powerful insights into the structural, energetics, and electronic phenomena that underlie heterogeneous catalysis on transition metal nanoparticles. Such calculations are now routinely applied to single crystal metal surfaces...... and to subnanometer metal clusters. Descriptions of catalysis on truly nanosized structures, however, are generally not as well developed. In this talk, I will illustrate different approaches to analyzing nanocatalytic phenomena with DFT calculations. I will describe case studies from heterogeneous catalysis...

  5. Applying functional genomics research to the study of pig reproduction.

    Science.gov (United States)

    Pomp, D; Caetano, A R; Bertani, G R; Gladney, C D; Johnson, R K

    2001-01-01

    Functional genomics is an experimental approach that incorporates genome-wide or system-wide experimentation, expanding the scope of biological investigation from studying single genes to studying potentially all genes at once in a systematic manner. This technology is highly appealing because of its high throughput and relatively low cost. Furthermore, analysis of gene expression using microarrays is likely to be more biologically relevant than the conventional paradigm of reductionism, because it has the potential to uncover new biological connections between genes and biochemical pathways. However, functional genomics is still in its infancy, especially with regard to the study of pig reproduction. Currently, efforts are centred on developing the necessary resources to enable high throughput evaluation and comparison of gene expression. However, it is clear that in the near future functional genomics will be applied on a large scale to study the biology and physiology of reproduction in pigs, and to understand better the complex nature of genetic control over polygenic characteristics, such as ovulation rate and litter size. We can look forward to generating a significant amount of new data on differences in gene expression between genotypes, treatments, or at various temporal and spatial coordinates within a variety of reproductively relevant systems. Along with this capability will be the challenge of collating, analysing and interpreting datasets that are orders of magnitude more extensive and complex than those currently used. Furthermore, integration of functional genomics with traditional genetic approaches and with detailed analysis of the proteome and relevant whole animal phenotypes will be required to make full use of this powerful new experimental paradigm as a beneficial research tool.

  6. Density functional theory study on the molecular structure of loganin

    OpenAIRE

    Pandey, Anoop Kumar; Siddiqui, Shamoon Ahmad; Dwivedi, Apoorva; Raj, Kanwal; Misra, Neeraj

    2011-01-01

    The computational Quantum Chemistry (QC) has been used for different types of problems, for example: structural biology, surface phenomena and liquid phase. In this paper we have employed the density functional method for the study of molecular structure of loganin. The equilibrium geometry, harmonic vibrational frequencies and infrared intensities were calculated by B3LYP/6-311G (d, p) method and basis set combinations. It was found that the optimized parameters obtained by the DFT/B3LYP met...

  7. Electron crystallography for structural and functional studies of membrane proteins.

    Science.gov (United States)

    Fujiyoshi, Yoshinori

    2011-01-01

    Membrane proteins are important research targets for basic biological sciences and drug design, but studies of their structure and function are considered difficult to perform. Studies of membrane structures have been greatly facilitated by technological and instrumental advancements in electron microscopy together with methodological advancements in biology. Electron crystallography is especially useful in studying the structure and function of membrane proteins. Electron crystallography is now an established method of analyzing the structures of membrane proteins in lipid bilayers, which resembles their natural biological environment. To better understand the neural system function from a structural point of view, we developed the cryo-electron microscope with a helium-cooled specimen stage, which allows for analysis of the structures of membrane proteins at a resolution higher than 3 Å. This review introduces recent instrumental advances in cryo-electron microscopy and presents some examples of structure analyses of membrane proteins, such as bacteriorhodopsin, water channels and gap junction channels. This review has two objectives: first, to provide a personal historical background to describe how we came to develop the cryo-electron microscope and second, to discuss some of the technology required for the structural analysis of membrane proteins based on cryo-electron microscopy.

  8. Yeast studies reveal moonlighting functions of the ancient actin cytoskeleton

    Science.gov (United States)

    Sattlegger, Evelyn; Chernova, Tatiana A.; Gogoi, Neeku M.; Pillai, Indu V.; Chernoff, Yury O.; Munn, Alan L.

    2014-01-01

    Classic functions of the actin cytoskeleton include control of cell size and shape and the internal organisation of cells. These functions are manifest in cellular processes of fundamental importance throughout biology such as the generation of cell polarity, cell migration, cell adhesion and cell division. However, studies in the unicellular model eukaryote Saccharomyces cerevisiae (Baker's yeast) are giving insights into other functions in which the actin cytoskeleton plays a critical role. These include endocytosis, control of protein translation and determination of protein 3-dimensional shape (especially conversion of normal cellular proteins into prions). Here we present a concise overview of these new "moonlighting" roles for the actin cytoskeleton and how some of these roles might lie at the heart of important molecular switches. This is an exciting time for researchers interested in the actin cytoskeleton. We show here how studies of actin are leading us into many new and exciting realms at the interface of genetics, biochemistry and cell biology. While many of the pioneering studies have been conducted using yeast, the conservation of the actin cytoskeleton and its component proteins throughout eukaryotes suggests that these new roles for the actin cytoskeleton may not be restricted to yeast cells but rather may reflect new roles for the actin cytoskeleton of all eukaryotes. PMID:25138357

  9. Renal Function and Hemodynamic Study in Obese Zucker Rats

    Science.gov (United States)

    Park, Sung Kwang; Kang, Sung Kyew

    1995-01-01

    Objectives To investigate the renal function and hemodynamic changes in obesity and hyperinsulinemia which are characteristics of type II diabetes. Methods Studies were carried out in two groups of female Zucker rats. Group 1 rats were obese Zucker rats with hereditary insulin resistance. Group 2 rats were lean Zucker rats and served as controls. In comparison with lean Zucker rats, obese Zucker rats exhibited hyperinsulinemia but normoglycemia. Micropuncture studies and morphologic studies were performed in these rats. Results Functional studies showed that obese Zucker rats exhibited increases in kidney weight and GFR(obese Zucker, 1.23±.07)ml/min; lean Zucker, 0.93±.03ml/min). Micropuncture studies revealed that the increase in GFR in obese Zucker rats was attributable to the increases in the single nephron plasma flow rate and glomerular transcapillary hydraulic pressure. The glomerular ultrafiltration coefficient was the same in both groups. Morphologic studies revealed that the increase in GFR in obese Zucker rats was associated with an increase in glomerular volume. Conclusions These results suggest that obesity and hyperinsulinemia, which are the characteristics of type II diabetes, can be associated with glomerular hyperfiltration and glomerular capillary hypertension. PMID:7626557

  10. Theoretical study for the interlamellar aminoalcohol functionalization of kaolinite

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Xin-Juan [Key Laboratory of Green Process and Engineering, National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Li, Huiquan, E-mail: hqli@home.ipe.ac.cn [Key Laboratory of Green Process and Engineering, National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Liu, Qinfu; Cheng, Hongfei [School of Geoscience and Surveying Engineering, China University of Mining and Technology, Beijing 100083 (China); He, Peng; Li, Shaopeng [Key Laboratory of Green Process and Engineering, National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China)

    2015-08-30

    Graphical abstract: - Highlights: • The results indicated that aminoalcohols exist with a mixing of intercalation and grafting. • Aminoalcohols can form strong hydrogen bonds with Al octahedral sheet. • The interaction between aminoalcohols and Si tetrahedral sheet are mainly attributed by vdW force. • Aminoalcohols grafting or intercalating on kaolinite have strong reactivity as electron donors. - Abstract: Fundamental problems related to aminoalcohols intercalating on kaolinite were investigated by using density functional theory method. This study examines the adsorption modes of diethanolamine and triethanolamine on kaolinite, the role of hydrogen bonds and van der Waals (vdW) forces between aminoalcohols and interlayer of kaolinite, and the change of molecular orbital occupancies of functionalized kaolinite. Results show that functionalized kaolinite is physically intercalated and covalently grafted by aminoalcohols. Non-covalent interaction analysis provides a visualized description that intercalated aminoalcohols form strong hydrogen bonds with Al octahedral sheet, and the interaction between aminoalcohols and Si tetrahedral sheet is mainly attributed to weak vdW force. The analysis of molecular orbital occupancies for kaolinite complex showed that the functionalized kaolinite has strong chemical reactivity as electron donors on the sites of grafted or intercalated aminoalcohols for further chemical reaction with other materials.

  11. Functional models of power electronic components for system studies

    Science.gov (United States)

    Tam, Kwa-Sur; Yang, Lifeng; Dravid, Narayan

    1991-01-01

    A novel approach to model power electronic circuits has been developed to facilitate simulation studies of system-level issues. The underlying concept for this approach is to develop an equivalent circuit, the functional model, that performs the same functions as the actual circuit but whose operation can be simulated by using larger time step size and the reduction in model complexity, the computation time required by a functional model is significantly shorter than that required by alternative approaches. The authors present this novel modeling approach and discuss the functional models of two major power electronic components, the DC/DC converter unit and the load converter, that are being considered by NASA for use in the Space Station Freedom electric power system. The validity of these models is established by comparing the simulation results with available experimental data and other simulation results obtained by using a more established modeling approach. The usefulness of this approach is demonstrated by incorporating these models into a power system model and simulating the system responses and interactions between components under various conditions.

  12. Chemical functionalization of graphene via aryne cycloaddition: a theoretical study.

    Science.gov (United States)

    Zhao, Jing-xiang; Wang, Hong-xia; Gao, Bo; Wang, Xiao-guang; Cai, Qing-hai; Wang, Xuan-zhang

    2012-06-01

    Chemical functionalization of graphene provides a promising route to improve its solubility in water and organic solvents as well as modify its electronic properties, thus significantly expanding its potential applications. In this article, by using density functional theory (DFT) methods, we have studied the effects of the chemical functionalization of graphenes via aryne cycloaddition on its properties. We found that the adsorption of an isolated aryne group on the graphene sheet is very weak with the adsorption energy of -0.204 eV, even though two new single C-C interactions are formed between the aryne group and the graphene. However, the interaction of graphene with the aryne group can be greatly strengthened by (i) substituting the H-atoms in aryne group with F-, Cl-, -NO(2) (electron-withdrawing capability), or CH(3)-group (electron-donating capability), and (ii) increasing the coverage of the adsorbed aryne groups on the graphene sheet. As expected, the strongest bonding is found on the graphene edges, in which the adsorbed aryne groups prefer to be far away from each other. Interestingly, chemical functionalization with aryne groups leads to an opening of the band gap of graphene, which is dependent on the coverage of the adsorbed aryne groups. The present work provides an insight into the modifications of graphene with aryne groups in experiment.

  13. Platelet function studies in women on oral contraceptive pills.

    Science.gov (United States)

    Ishak, R; Mohamed, A B; Hassan, K

    1990-06-01

    A study was conducted on a total of 100 women attending the Family Planning Clinic in Kuala Lumpur. 50 took combined low-dose estrogen and progesterone pills for a year or more and the other 50 used different methods of birth control. Platelet aggregation, ATP release, Thromboxane B2, and 6-keto-prostaglandin F1alpha estimations were made to evaluate the effect of oral contraceptives (OCs) on platelet function and prostanoid production. The results showed no significant differences in the parameters measured in the 2 groups investigated. These findings are comparable to those reported by other studies, suggesting relatively low risk, if any, of thrombosis in OC users.

  14. Effect of orthostasis on endothelial function: a gender comparative study.

    Directory of Open Access Journals (Sweden)

    Nandu Goswami

    Full Text Available As the vascular endothelium has multiple functions, including regulation of vascular tone, it may play a role in the pathophysiology of orthostatic intolerance. We investigated the effect of orthostasis on endothelial function using EndoPAT®, a non-invasive and user-independent method, and across gender. As sex steroid hormones are known to affect endothelial function, this study examined the potential effect of these hormones on the endothelial response to orthostasis by including females at different phases of the menstrual cycle (follicular and luteal-where the hormone balance differs, and females taking an oral contraceptive. A total of 31 subjects took part in this study (11 males, 11 females having normal menstrual cycles and 9 females taking oral contraceptive. Each subject made two visits for testing; in the case of females having normal menstrual cycles the first session was conducted either 1-7 (follicular or 14-21 days (luteal after the start of menstruation, and the second session two weeks later, i.e., during the other phase, respectively. Endothelial function was assessed at baseline and following a 20-min orthostatic challenge (active standing. The EndoPAT® index increased from 1.71 ± 0.09 (mean ± SEM at baseline to 2.07 ± 0.09 following orthostasis in females (p<0.001. In males, the index increased from 1.60 ± 0.08 to 1.94 ± 0.13 following orthostasis (p<0.001. There were no significant differences, however, in the endothelial response to orthostasis between females and males, menstrual cycle phases and the usage of oral contraceptive. Our results suggest an increased vasodilatatory endothelial response following orthostasis in both females and males. The effect of gender and sex hormones on the endothelial response to orthostasis appears limited. Further studies are needed to determine the potential role of this post orthostasis endothelial response in the pathophysiology of orthostatic intolerance.

  15. Advances in PET imaging of P-glycoprotein function at the blood-brain barrier.

    Science.gov (United States)

    Syvänen, Stina; Eriksson, Jonas

    2013-02-20

    Efflux transporter P-glycoprotein (P-gp) at the blood-brain barrier (BBB) restricts substrate compounds from entering the brain and may thus contribute to pharmacoresistance observed in patient groups with refractory epilepsy and HIV. Altered P-gp function has also been implicated in neurodegenerative diseases such as Alzheimer's and Parkinson's disease. Positron emission tomography (PET), a molecular imaging modality, has become a promising method to study the role of P-gp at the BBB. The first PET study of P-gp function was conducted in 1998, and during the past 15 years two main categories of P-gp PET tracers have been investigated: tracers that are substrates of P-gp efflux and tracers that are inhibitors of P-gp function. PET, as a noninvasive imaging technique, allows translational research. Examples of this are preclinical investigations of P-gp function before and after administering P-gp modulating drugs, investigations in various animal and disease models, and clinical investigations regarding disease and aging. The objective of the present review is to give an overview of available PET radiotracers for studies of P-gp and to discuss how such studies can be designed. Further, the review summarizes results from PET studies of P-gp function in different central nervous system disorders.

  16. Ciliobrevins as Tools for Studying Dynein Motor Function

    Directory of Open Access Journals (Sweden)

    Douglas eRoossien

    2015-07-01

    Full Text Available Dyneins are a small class of molecular motors that bind to microtubules and walk towards their minus ends. They are essential for the transport and distribution of organelles, signaling complexes and cytoskeletal elements. In addition dyneins generate forces on microtubule arrays that power the beating of cilia and flagella, cell division, migration and growth cone motility. Classical approaches to the study of dynein function in axons involve the depletion of dynein, expression of mutant/truncated forms of the motor, or interference with accessory subunits. By necessity, these approaches require prolonged time period for the expression or manipulation of cellular dynein levels. With the discovery of the ciliobrevins, a class of cell permeable small molecule inhibitors of dynein, it is now possible to acutely disrupt dynein both globally and locally. In this review, we briefly summarize recent work using ciliobrevins to inhibit dynein and discuss the insights ciliobrevins have provided about dynein function in various cell types with a focus on neurons. We temper this with a discussion of the need for studies that will elucidate the mechanism of action of ciliobrevin and as well as the need for experiments to further analyze the specificity of ciliobreviens for dynein. Although much remains to be learned about ciliobrevins, these small molecules are proving themselves to be valuable novel tools to assess the cellular functions of dynein.

  17. Hybrid functional studies of defects and hole polarons in oxides

    Science.gov (United States)

    Varley, Joel

    Transparent conducting oxides (TCOs) are ubiquitous, appearing in windows, flat-panel displays, solar cells, solid-state lighting, and transistors that all exploit TCOs' combination of high electrical conductivity and optical transparency. Thanks to this large and growing list of applications, there has been a surge of interest in the science of these materials, focusing on the fundamental properties and doping opportunities in traditional TCOs as well as the exploration of promising new candidate materials. Hybrid density functional theory has proven instrumental in elucidating the physics of TCOs. One example is the study of dopants and defects that determine the conductivity. Accurate formation energies and charge-state transition levels can now be obtained thanks to the accurate electronic structure provided by a hybrid functional. This allows us to address the origins of unintentional conductivity: for SnO2, In2O3, and Ga2O3, we demonstrate that this is not due to native defects such as oxygen vacancies, but must be attributed to unintentional incorporation of impurities. We can also provide guidelines for achieving higher doping levels, suggesting several impurities as candidate donors with high solubility. Limitations on doping due to the formation or incorporation of compensating centers are addressed as well. Hybrid functional calculations also overcome the shortcomings associated with traditional local or semi-local functionals, which do not properly describe charge localization. Hybrid functionals accurately describe polaron formation, i.e., the self-trapping of holes when p - type doping of the oxide materials is attempted. Consequences of polaron formation for optical characterization of the material will be discussed. This work was performed in collaboration with Anderson Janotti and Chris G. Van de Walle, and was in part under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  18. Functional versus Nonfunctional Rehabilitation in Chronic Ischemic Stroke: Evidences from a Randomized Functional MRI Study

    Directory of Open Access Journals (Sweden)

    Maristela C. X. Pelicioni

    2016-01-01

    Full Text Available Motor rehabilitation of stroke survivors may include functional and/or nonfunctional strategy. The present study aimed to compare the effect of these two rehabilitation strategies by means of clinical scales and functional Magnetic Resonance Imaging (fMRI. Twelve hemiparetic chronic stroke patients were selected. Patients were randomly assigned a nonfunctional (NFS or functional (FS rehabilitation scheme. Clinical scales (Fugl-Meyer, ARA test, and modified Barthel and fMRI were applied at four moments: before rehabilitation (P1 and immediately after (P2, 1 month after (P3, and three months after (P4 the end of rehabilitation. The NFS group improved significantly and exclusively their Fugl-Meyer scores at P2, P3, and P4, when compared to P1. On the other hand, the FS group increased significantly in Fugl-Meyer at P2, when compared to P1, and also in their ARA and Barthel scores. fMRI inspection at the individual level revealed that both rehabilitation schemes most often led to decreased activation sparseness, decreased activity of contralesional M1, increased asymmetry of M1 activity to the ipsilesional side, decreased perilesional activity, and decreased SMA activity. Increased M1 asymmetry with rehabilitation was also confirmed by Lateralization Indexes. Our clinical analysis revealed subtle differences between FS and NFS.

  19. Configurational study of amino-functionalized silica surfaces: A density functional theory modeling.

    Science.gov (United States)

    Hozhabr Araghi, Samira; Entezari, Mohammad H; Sadeghi Googheri, Mohammad Sadegh

    2015-06-01

    Despite extensive studies of the amino-functionalized silica surfaces, a comprehensive investigation of the effects of configuration and hydrolysis of 3-aminopropyltriethoxysilan (APTES) molecules attached on silica has not been studied yet. Therefore, the methods of quantum mechanics were used for the study of configuration and hydrolysis forms of APTES molecules attached on the surface. For this purpose, five different categories based on the number of hydrolyzed ethoxy groups including 16 configurations were designed and analyzed by the density functional theory (DFT) method. The steric hindrance as an effective factor on the stability order was extracted from structural analysis. Other impressive parameters such as the effects of hydrogen bond and electron delocalization energy were obtained by using the atoms in molecules (AIM) and natural bond orbitals (NBO) theories. Consequently, it was found that the stability of configurations was attributed to steric effects, hydrogen bond numbers and electron delocalization energy. The maximum stability was achieved when at least two of these parameters cooperate with each other.

  20. Current studies on physiological functions and biological production of lactosucrose.

    Science.gov (United States)

    Mu, Wanmeng; Chen, Qiuming; Wang, Xiao; Zhang, Tao; Jiang, Bo

    2013-08-01

    Lactosucrose (O-β-D-galactopyranosyl-(1,4)-O-α-D-glucopyranosyl-(1,2)-β-D-fructofuranoside) is a trisaccharide formed from lactose and sucrose by enzymatic transglycosylation. This rare trisaccharide is a kind of indigestible carbohydrate, has good prebiotic effect, and promotes intestinal mineral absorption. It has been used as a functional ingredient in a range of food products which are approved as foods for specified health uses in Japan. Using lactose and sucrose as substrates, lactosucrose can be produced through transfructosylation by β-fructofuranosidase from Arthrobacter sp. K-1 or a range of levansucrases, or through transgalactosylation by β-galactosidase from Bacillus circulans. This article presented a review of recent studies on the physiological functions of lactosucrose and the biological production from lactose and sucrose by different enzymes.

  1. The functions of laminins: lessons from in vivo studies

    DEFF Research Database (Denmark)

    Ryan, M C; Christiano, A M; Engvall, E;

    1996-01-01

    This series of three short reviews is an attempt to summarize our current knowledge of the in vivo tests of hypotheses of laminin functions. The structures of the laminins have been thoroughly reviewed recently (P. Ekblom and R. Timpl, in press), and I will not attempt to repeat this information...... here. Instead, I will focus on the recent evidence gathered from gene knock out experiments in mice and from naturally occurring human and mouse gene mutations. The most obvious lesson from the above studies--other than demonstrating the importance of laminins in general--is that the structural...... normal-other than the anchoring complex itself. The pathology observed in the newborn is believed to be due to the frictional trauma of birth, with the expectation that the function of the fetal skin is normal in utero. The Herlitz epidermolysis bullosa phenotype is obvious immediately at birth...

  2. Cognitive function in the affective disorders: a prospective study.

    Science.gov (United States)

    Bulbena, A; Berrios, G E

    1993-01-01

    A prospective, controlled study of 50 subjects confirmed claims that major depression or mania may cause temporary disorders of attention, memory, visuo-spatial function, and choice reaction time, and cause-independently of medication-the appearance of glabellar tap, positive hand-face test, nuchocephalic reflex, and graphesthesia. On follow-up, all these phenomena either disappeared or markedly improved. Age and age of onset, but not pre-morbid intelligence or history of ECT, seemed to modulate the severity of the cognitive impairment. Presence of delusions predicted poor (but reversible) visuo-spatial function. Cognitive impairment accompanied by reversible soft neurological signs was more marked but patients thus affected surprisingly showed lower depressive scores; this was interpreted as representing a secondary, 'organic' form of affective disorder (i.e. a behavioural phenocopy of depression) characterised by a reduced capacity to experience depressive symptoms and by little improvement at follow-up.

  3. Functional near-infrared spectroscopy studies in children

    Directory of Open Access Journals (Sweden)

    Nagamitsu Shinichiro

    2012-03-01

    Full Text Available Abstract Psychosomatic and developmental behavioral medicine in pediatrics has been the subject of significant recent attention, with infants, school-age children, and adolescents frequently presenting with psychosomatic, behavioral, and psychiatric symptoms. These may be a consequence of insecurity of attachment, reduced self-confidence, and peer -relationship conflicts during their developmental stages. Developmental cognitive neuroscience has revealed significant associations between specific brain lesions and particular cognitive dysfunctions. Thus, identifying the biological deficits underlying such cognitive dysfunction may provide new insights into therapeutic prospects for the management of those symptoms in children. Recent advances in noninvasive neuroimaging techniques, and especially functional near-infrared spectroscopy (NIRS, have contributed significant findings to the field of developmental cognitive neuroscience in pediatrics. We present here a comprehensive review of functional NIRS studies of children who have developed normally and of children with psychosomatic and behavioral disorders.

  4. Functional genomic approach to the study of biodiversitywithin Trichoderma

    Institute of Scientific and Technical Information of China (English)

    Monte E; Hermosa M R; González F J; Rey M; Cardoza R E; Gutiérrez S; Delgado Jarana J; Llobell A

    2004-01-01

    @@ Trichoderma is a fungal genus of great and demonstrable biotechnological value, but its genome is poorly surveyed compared with other model microorganisms. Due to their ubiquity and rapid substrate colonization, Trichoderma species have been widely used as biocontrol organisms for agriculture, and their enzyme systems are widely used in industry. Therefore, there is a clear interest to explore beyond the phenotype to exploit the underlying genetic systems using functional genomics tools. The great diversity of species within the Trichoderma genus, the absence of optimized systems for its exploration, and the great variety of genes expressed under a wide range of ambient conditions are the main challenges to consider when starting a comprehensive functional genomics study. An initial project started by three Spanish groups has been extended into the project TRICHOEST, funded by the EU (FP5, QLRT-2001-02032) to target the transcriptome analysis of selected Trichoderma strains with biocontrol potential, in conditions related to antagonism, nutrient stress and plant interactions. Once specific conditions were defined, cDNA libraries were produced and used for EST sequencing. Nine strains from seven Trichoderma species have been considered in this study and an important amount of gene sequence data has been generated, analyzed and used to compare the gene expression in different strains.In parallel to sequencing, genomic expression studies were carried out by means of macro-arrays to identify genes expressed in specific conditions. In silico analysis of DNA sequencing data together with macro-array expression results have lead to a selection based on the potential use of the gene sequences.The selected clone sequences were completed and cloned in appropriate vectors to initiate functional analysis by means of expression studies in homologous and heterologous systems.

  5. Insilico studies of organosulfur-functional active compounds in garlic.

    Science.gov (United States)

    Singh, Yogendra P; Singh, Ram A

    2010-01-01

    Garlic has been used medicinally since antiquity because of its antimicrobial activity, anticancer activity, antioxidant activity, ability to reduce cardiovascular diseases, improving immune functions, and antidiabetic activities and also in reducing cardiovascular diseases and improving immune functions. Recent studies identify that the wide variety of medicinal functions are attributed to the sulfur compounds present in garlic. Epidemiological observations and laboratory studies in animal models have also showed anticarcinogenic potential of organosulfur compounds of garlic. In this study, in silico analysis of organosulfur compounds is reported using the methods of theoretical chemistry to elucidate the molecular properties of garlic as it is more time and cost efficient, reduces the number of wet experiments, and offers the possibility of replacing some animal tests with suitable in silico models. The analysis of molecular descriptors defined by Lipinski has been done. The solubility of drug in water has been determined as it is of useful importance in the process of drug discovery from molecular design to pharmaceutical formulation and biopharmacy. All toxicities associated with candidate drug have been calculated. P-Glycoprotein expressed in normal tissues as a cause of drug pharmacokinetics and pharmacodynamics has been examined. Drug-plasma protein binding and volume of distribution have also been calculated. To avoid rejection of drugs, it is becoming more important to determine pK(a), absorption, polar surface area, and other physiochemical properties associated with a drug, before synthetic work is undertaken. The present in silico study is aimed at examining these compounds of garlic to evaluate its possible efficacy and toxicity under conditions of actual use in humans.

  6. A comparative study of density functional and density functional tight binding calculations of defects in graphene

    Energy Technology Data Exchange (ETDEWEB)

    Zobelli, Alberto [Laboratoire de Physique des Solides, Univ. Paris Sud, CNRS UMR, Orsay (France); Ivanovskaya, Viktoria; Wagner, Philipp; Yaya, Abu; Ewels, Chris P. [Institut des Materiaux Jean Rouxel (IMN), CNRS UMR, University of Nantes (France); Suarez-Martinez, Irene [Nanochemistry Research Institute, Curtin University of Technology, Perth, Western Australia (Australia)

    2012-02-15

    The density functional tight binding approach (DFTB) is well adapted for the study of point and line defects in graphene based systems. After briefly reviewing the use of DFTB in this area, we present a comparative study of defect structures, energies, and dynamics between DFTB results obtained using the dftb+ code, and density functional results using the localized Gaussian orbital code, AIMPRO. DFTB accurately reproduces structures and energies for a range of point defect structures such as vacancies and Stone-Wales defects in graphene, as well as various unfunctionalized and hydroxylated graphene sheet edges. Migration barriers for the vacancy and Stone-Wales defect formation barriers are accurately reproduced using a nudged elastic band approach. Finally we explore the potential for dynamic defect simulations using DFTB, taking as an example electron irradiation damage in graphene. DFTB-MD derived sputtering energy threshold map for a carbon atom in a graphene plane. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Steroid-Functionalized Titanocenes: Docking Studies with Estrogen Receptor Alpha

    Directory of Open Access Journals (Sweden)

    Li Ming Gao

    2016-11-01

    Full Text Available Estrogen receptor alpha (ERα is a transcription factor that is activated by hormones, with 17β-estradiol being its most active agonist endogenous ligand. ERα is also activated or inactivated by exogenous ligands. ER is overexpressed in hormone-dependent breast cancer, and one of the treatments for this type of cancer is the use of an ER antagonist to halt cell proliferation. We have previously reported four steroid-functionalized titanocenes: pregnenolone, dehydroepiandrosterone (DHEA, trans-androsterone, and androsterone. These steroids have hormonal activity as well as moderate antiproliferative activity, thus these steroids could act as vectors for the titanocene dichloride to target hormone-dependent cancers. Also, these steroids could increase the antiproliferative activity of the resulting titanocenes based on synergism. In order to elucidate which factors contribute to the enhanced antiproliferative activity of these steroid-functionalized titanocenes, we performed docking studies between ERα and the titanocenes and the steroids. The binding affinities and type of bonding interactions of the steroid-functionalized titanocenes with ERα are herein discussed.

  8. STUDYING OF FUNCTIONAL CONDITION OF THE SMALL INTESTINE IN CHOLELITHIASIS

    Directory of Open Access Journals (Sweden)

    Ya. M. Vakhrushev

    2015-01-01

    Full Text Available Aim. Complex research of the functional condition of the small intestine in different stages of cholelithiasis.Materials and methods. 47 patients with different stages of cholelithiasis were examined. There were 29 patients with the first (prestone stage and 18 — with the second (stone stage of cholelithiasis. In an assessment of the functional condition of the small intestine were used clinical data and results of the load tests by sugars. Cavitary digestion was studied by load test with polysaccharide (soluble starch, membrane digestion — with disaccharide (sucrose, absorption — with monosaccharide (glucose. Glucose level in blood was determined on an empty stomach, then after oral reception of 50g of glucose, sucrose or starch in 30, 60 and 120 minutes.Results. Researchers showed that in the most of patients with cholelithiasis there were disturbances in clinical and functional condition of the small intestine. In an assessment of the cavitary digestion the level of glycemia was authentically lowered by 43% in prestone stage and by 66% in stone stage of cholelithiasis in comparison with control. In an assessment of membrane digestion in patients with the stone stage of cholelithiasis the level of glycemia was lowered in comparison with group of control and with the prestone stage by 30% and 19% respectively.Conclusion. In prestone stage of cholelithiasis there were decrease of the cavitary digestion primary, and in stone stage of cholelithiasis — all stages of hydrolysis-resorptive process in the small intestine were disturbed.

  9. Graphene oxide and adsorption of chloroform: a density functional study

    CERN Document Server

    Kuisma, Elena; Lindberg, Th Benjamin; Gillberg, Christoffer A; Idh, Sebastian; Schroder, Elsebeth

    2016-01-01

    Chlorinated hydrocarbon compounds are of environmental concerns, since they are toxic to humans and other mammals, are widespread, and exposure is hard to avoid. Understanding and improving methods to reduce the amount of the substances is important. We present an atomic-scale calculational study of the adsorption of chlorine-based substance chloroform (CHCl3) on graphene oxide, as a step in estimating the capacity of graphene oxide for filtering out such substances, e.g., from drinking water. The calculations are based on density functional theory (DFT), and the recently developed consistent-exchange functional for the van der Waals density-functional method (vdW-DF-cx) is employed. We obtain values of the chloroform adsorption energy varying from roughly 0.2 to 0.4 eV per molecule. This is comparable to previously found results for chloroform adsorbed directly on clean graphene, using similar calculations. In a wet environment, like filters for drinking water, the graphene will not stay clean and will likel...

  10. Methodological considerations regarding the use of inorganic {sup 197}Hg(II) radiotracer to assess mercury methylation potential rates in lake sediment

    Energy Technology Data Exchange (ETDEWEB)

    Perez Catan, Soledad [Laboratorio de Analisis por Activacion Neutronica, Comision Nacional de Energia Atomica, Centro Atomico Bariloche, 8400 Bariloche (Argentina); Guevara, Sergio Ribeiro [Laboratorio de Analisis por Activacion Neutronica, Comision Nacional de Energia Atomica, Centro Atomico Bariloche, 8400 Bariloche (Argentina)], E-mail: ribeiro@cab.cnea.gov.ar; Marvin-DiPasquale, Mark [US Geological Survey, 345 Middlefield Rd./MS 480, Menlo Park, CA 94025 (United States); Magnavacca, Cecilia [Centro Atomico Ezeiza, Comision Nacional de Energia Atomica, Presbitero Gonzalez y Aragon No. 15, B1802AYA, Ezeiza, Buenos Aires (Argentina); Cohen, Isaac Marcos [Departamento de Ingenieria Quimica, Facultad Regional Buenos Aires, Universidad Tecnologica Nacional, Medrano 951 (C1179AAQ) Buenos Aires (Argentina); Arribere, Maria [Laboratorio de Analisis por Activacion Neutronica, Comision Nacional de Energia Atomica, Centro Atomico Bariloche, 8400 Bariloche (Argentina)

    2007-09-15

    Methodological considerations on the determination of benthic methyl-mercury (CH{sub 3}Hg) production potentials were investigated on lake sediment, using {sup 197}Hg radiotracer. Three methods to arrest bacterial activity were compared: flash freezing, thermal sterilization, and {gamma}-irradiation. Flash freezing showed similar CH{sub 3}Hg recoveries as thermal sterilization, which was both 50% higher than the recoveries obtained with {gamma}-ray irradiation. No additional radiolabel was recovered in kill-control samples after an additional 24 or 65 h of incubation, suggesting that all treatments were effective at arresting Hg(II)-methylating bacterial activity, and that the initial recoveries are likely due to non-methylated {sup 197}Hg(II) carry-over in the organic extraction and/or [{sup 197}Hg]CH{sub 3}Hg produced via abiotic reactions. Two CH{sub 3}Hg extraction methods from sediment were compared: (a) direct extraction into toluene after sediment leaching with CuSO{sub 4} and HCl and (b) the same extraction with an additional back-extraction step to thiosulphate. Similar information was obtained with both methods, but the low efficiency observed and the extra work associated with the back-extraction procedure represent significant disadvantages, even tough the direct extraction involves higher Hg(II) carry over.

  11. Methodological considerations regarding the use of inorganic 197Hg(II) radiotracer to assess mercury methylation potential rates in lake sediment

    Science.gov (United States)

    Perez, Catan S.; Guevara, S.R.; Marvin-DiPasquale, M.; Magnavacca, C.; Cohen, I.M.; Arribere, M.

    2007-01-01

    Methodological considerations on the determination of benthic methyl-mercury (CH3Hg) production potentials were investigated on lake sediment, using 197Hg radiotracer. Three methods to arrest bacterial activity were compared: flash freezing, thermal sterilization, and ??-irradiation. Flash freezing showed similar CH3Hg recoveries as thermal sterilization, which was both 50% higher than the recoveries obtained with ??-ray irradiation. No additional radiolabel was recovered in kill-control samples after an additional 24 or 65 h of incubation, suggesting that all treatments were effective at arresting Hg(II)-methylating bacterial activity, and that the initial recoveries are likely due to non-methylated 197Hg(II) carry-over in the organic extraction and/or [197Hg]CH3Hg produced via abiotic reactions. Two CH3Hg extraction methods from sediment were compared: (a) direct extraction into toluene after sediment leaching with CuSO4 and HCl and (b) the same extraction with an additional back-extraction step to thiosulphate. Similar information was obtained with both methods, but the low efficiency observed and the extra work associated with the back-extraction procedure represent significant disadvantages, even tough the direct extraction involves higher Hg(II) carry over. ?? 2007 Elsevier Ltd. All rights reserved.

  12. Radiosynthesis of 9{sup 9mT}c(CO){sup 3C}linafloxacin Dithiocarbamate and Its Biological Evaluation as a Potential staphylococcus aureus Infection Radiotracer

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Syed Qaiser; Khan, Mohammad Rafiullah; Ali, Syed Mohammad [Univ. of Peshawar/Univ. of Engineering and Technology Peshawar, Peshawar (Pakistan)

    2011-12-15

    Clinafloxacin dithiocarbamate (CNND) was radiolabeled with technetium 99m ({sup 99mT}c) using [{sup 99mT}c(CO){sub 3}(H{sub 2O}){sub 3]}{sup +a}nd assessed for its radiochemical stability in saline and serum, its in vitro binding with methicillin resistant Staphylococcus aureus (MRSA) and biodistribution in female nude mice (FNM) artificially infected with live and heat killed MRSA. In normal saline (NS) the {sup 99mT}c(CO){sub 3c}linafloxacin dithiocarbamate ({sup 99mT}c(CO){sub 3C}NND) showed radiochemical stability with a maximum value of 99.10{+-}0.20% and remained stable up to 4 h (92.65{+-}0.18%). In human serum at 37.deg.C within 16 h of incubation, 14.85% side products as a result of de tagging developed. Incubation with MRSA gave saturated binding with a maximum value of 72.75{+-}1.20%. Almost six fold higher uptake was seen in the infected and normal muscle. The {sup 99mT}c (CO){sub 3C}NND complex showed a normal route of excretion from the body of the FNM model. The higher stability in NS, HS, saturated in vitro binding with a live strain of MRSA and six fold higher uptake in the target organ showed the {sup 99mT}c(CO){sub 3C}NND complex to be a potential MRSA infection radiotracer.

  13. Methodological considerations regarding the use of inorganic 197Hg(II) radiotracer to assess mercury methylation potential rates in lake sediment.

    Science.gov (United States)

    Pérez Catán, Soledad; Guevara, Sergio Ribeiro; Marvin-DiPasquale, Mark; Magnavacca, Cecilia; Cohen, Isaac Marcos; Arribere, María

    2007-09-01

    Methodological considerations on the determination of benthic methyl-mercury (CH(3)Hg) production potentials were investigated on lake sediment, using (197)Hg radiotracer. Three methods to arrest bacterial activity were compared: flash freezing, thermal sterilization, and gamma-irradiation. Flash freezing showed similar CH(3)Hg recoveries as thermal sterilization, which was both 50% higher than the recoveries obtained with gamma-ray irradiation. No additional radiolabel was recovered in kill-control samples after an additional 24 or 65 h of incubation, suggesting that all treatments were effective at arresting Hg(II)-methylating bacterial activity, and that the initial recoveries are likely due to non-methylated (197)Hg(II) carry-over in the organic extraction and/or [(197)Hg]CH(3)Hg produced via abiotic reactions. Two CH(3)Hg extraction methods from sediment were compared: (a) direct extraction into toluene after sediment leaching with CuSO(4) and HCl and (b) the same extraction with an additional back-extraction step to thiosulphate. Similar information was obtained with both methods, but the low efficiency observed and the extra work associated with the back-extraction procedure represent significant disadvantages, even tough the direct extraction involves higher Hg(II) carry over.

  14. Measurement of Bmax and Kd with the glycine transporter 1 radiotracer ¹⁸F-MK6577 using a novel multi-infusion paradigm.

    Science.gov (United States)

    Xia, Yan; Zheng, Ming-Qiang; Holden, Daniel; Lin, Shu-fei; Kapinos, Michael; Ropchan, Jim; Gallezot, Jean-Dominique; Huang, Yiyun; Carson, Richard E

    2015-12-01

    Glycine is a co-agonist of glutamate at the NMDA receptor. Glycine transporter 1 (GlyT1) inhibitors are reported to be potential therapeutic agents for schizophrenia. (18)F-MK6577 is a new positron emission tomography (PET) radiotracer useful for imaging brain GlyT1 and its occupancy in humans. We devised a novel multi-infusion paradigm of radiolabeled and unlabeled compound and an iterative linear/nonlinear alternating fitting method to allow for the determination of in vivo affinity (Kd) and target concentration (Bmax) images, constraining Kd to be uniform across the brain. This paradigm was tested with (18)F-MK6577 in baboons. Voxel-based analysis produced high quality Bmax images and reliable Kd estimates, and also suggested that the nondisplaceable distribution volume (VND) is not uniform throughout the brain. In vivo GlyT1 Kd was estimated to be 1.87 nmol/L for (18)F-MK6577, and the rank order of GlyT1 distribution measured in the baboon brain was: high in the brainstem (133 nmol/L), medium in the cerebellum (83 nmol/L), and low in the cortex (30 nmol/L). These in vivo Kd and Bmax values agreed well with those determined in vitro, thus validating our novel multi-infusion approach.

  15. Novel [99mTcN]2+ Labeled EGFR Inhibitors as Potential Radiotracers for Single Photon Emission Computed Tomography (SPECT Tumor Imaging

    Directory of Open Access Journals (Sweden)

    Mingxia Zhao

    2014-04-01

    Full Text Available The epidermal growth factor receptor (EGFR is overexpressed in many cancers, including breast, ovarian, endometrial and non-small cell lung cancer. An EGFR-specific imaging agent could facilitate clinical evaluation of primary tumors or metastases. To achieve this goal, 4-(2-aminoethylamino-6,7-dimethoxyquinazoline (ADMQ was synthesized based on a 4-aminoquinazoline core and then conjugated with N-mercapto- acetylglycine (MAG and N-mercaptoacetyltriglycine (MAG3, respectively, to give compounds 1 and 2. The final complexes [99mTcN]-1 and [99mTcN]-2 were successfully obtained with radiochemical purities of >99% and >98% as measured by radio-HPLC. No decomposition of the two complexes at room temperature was observed over a period of 2 h. Their partition coefficients indicated they were hydrophilic and the electrophoresis results showed they were negatively charged. Biodistribution in tumor-bearing mice demonstrated that the two new complexes showed tumor accumulation, high tumor-tomuscle (T/M ratios and fast clearance from blood and muscle. Between the two compounds, the 99mTcN-MAG3-ADMQ ([99mTcN]-2 showed the better characteristics, with the tumor/muscle and tumor/blood ratios reached 2.11 and 1.90 at 60 min post-injection, 4.20 and 1.10 at 120 min post-injection, suggesting it could be a promising radiotracer for SPECT tumor imaging.

  16. A study of cardiovascular autonomic function in normal pregnancy

    Directory of Open Access Journals (Sweden)

    Sumana Panja

    2013-04-01

    Full Text Available Objective: The present study was designed to evaluate the physiological responses to noninvasive cardiovascular autonomic function tests in normal pregnancy and compare them with non- pregnant controls. Materials and Methods: The study population comprised of 90 apparently healthy, pregnant women divided equally into three groups based on their period of gestation and 30 otherwise healthy, non-pregnant women as controls. The standard autonomic function tests based on cardiovascular reflexes, including heart rate response tests and blood pressure response tests were performed. Result: It was observed that variability of mean between and within all the population groups and controls was significantly different. Multiple comparison analysis revealed a significantly lower Deep Breathing Difference in pregnant subjects, significant difference in Valsalva Ratio in third trimester group, a significantly lower Postural Tachycardia Index only during last trimester and a significantly higher fall in systolic blood pressure on standing only during 1st trimester. A significantly lower alteration in diastolic blood pressure during isometric handgrip in later trimesters and a significant increase in overall cardiovascular autonomic score between and within all groups were also observed. Conclusion: The observations serve to corroborate that the cardiovascular indices in pregnant women are significantly altered in comparison to non-pregnant women, thus highlighting the importance of cardiovascular monitoring during pregnancy. The study also helped to reaffirm the efficacy of simple cardiovascular reflex tests in research on pregnancy physiology.

  17. A codesign case study: implementing arithmetic functions in FPGAs

    DEFF Research Database (Denmark)

    Klotchkov, I. V.; Pedersen, Steen

    1996-01-01

    Different ways of implementing and designing arithmetic functions for 16/32 bit integers in FPGA technology are studied. A comparison of four different design methods is also included. The results are used to increase the overall system performance in a dedicated 3D image analysis prototype system...... by moving a vector length calculation from software to hardware. The conclusion is that by adding one relatively simple board containing two FPGAs in the prototype setup, the total computing time is reduced by 30%. The total amount of image data, in this case 300 Mbyte, which has to be transmitted via...

  18. Combing genomic DNA for structural and functional studies.

    Science.gov (United States)

    Schurra, Catherine; Bensimon, Aaron

    2009-01-01

    Molecular combing is a process whereby single DNA molecules bind by their extremities to a silanised surface and are then uniformly stretched and aligned by a receding air/water interface (1). This method, with a high resolution ranging from a few kilobases to megabases, has many applications in the field of molecular cytogenetics, allowing structural and functional analysis at the genome level. Here we describe protocols for preparing DNA for combing and for the use of fluorescent hybridisation (FH) applied to combed DNA to conduct physical mapping or genomic structural analysis. We also present the methodology for visualising and studying DNA replication using combed DNA.

  19. Study of the derivative expansions for the nuclear structure functions

    CERN Document Server

    Simo, I Ruiz

    2008-01-01

    We study the convergence of the series expansions sometimes used in the analysis of the nuclear effects in Deep Inelastic Scattering (DIS) proccesses induced by leptons. The recent advances in statistics and quality of the data, in particular for neutrinos calls for a good control of the theoretical uncertainties of the models used in the analysis. Using realistic nuclear spectral functions which include nucleon correlations, we find that the convergence of the derivative expansions to the full results is poor except at very low values of $x$.

  20. Density functional theory studies of doping in Titania

    OpenAIRE

    2010-01-01

    The structural and electronic properties of rutile and anatase, and the influence of both mono- and co-doping, have been studied using Density Functional Theory. Ge-doped anatase and rutile exhibit different band gap-narrowing mechanisms; in particular, host Ti 3d states move to lower energy regions in anatase and Ge 4s impurities states locate below the conduction band of rutile. For S-doping, S 3p states locate above the top of the valence band and mix with O 2p states, leading to band gap ...

  1. Utterance and Function in Genre Studies: A Literary Perspective

    DEFF Research Database (Denmark)

    Auken, Sune

    2015-01-01

    of the complexities involved when Genre Studies confront genres whose utterances are more complex than the “homely discourses” usually discussed in RGS. Formal and thematic features play a far too significant role in literary works to be explicable simply as derivations from function alone. But this is not limited...... to formal and thematic interpretations of genre, by allowing the utterances themselves to re-enter center stage. This enables an improved understanding of complex genres. It also revives close reading as a viable approach to understanding genre and thus to inform the rhetorical, linguistic, and sociological...

  2. Xenobiotic transporters: ascribing function from gene knockout and mutation studies.

    Science.gov (United States)

    Klaassen, Curtis D; Lu, Hong

    2008-02-01

    Transporter-mediated absorption, secretion, and reabsorption of chemicals are increasingly recognized as important determinants in the biological activities of many xenobiotics. In recent years, the rapid progress in generating and characterizing mice with targeted deletion of transporters has greatly increased our knowledge of the functions of transporters in the pharmacokinetics/toxicokinetics of xenobiotics. In this introduction, we focus on functions of transporters learned from experiments on knockout mice as well as humans and rodents with natural mutations of these transporters. We limit our discussion to transporters that either directly transport xenobiotics or are important in biliary excretion or cellular defenses, namely multidrug resistance, multidrug resistance-associated proteins, breast cancer resistance protein, organic anion transporting polypeptides, organic anion transporters, organic cation transporters, nucleoside transporters, peptide transporters, bile acid transporters, cholesterol transporters, and phospholipid transporters, as well as metal transporters. Efflux transporters in intestine, liver, kidney, brain, testes, and placenta can efflux xenobiotics out of cells and serve as barriers against the entrance of xenobiotics into cells, whereas many xenobiotics enter the biological system via uptake transporters. The functional importance of a given transporter in each tissue depends on its substrate specificity, expression level, and the presence/absence of other transporters with overlapping substrate preferences. Nevertheless, a transporter may affect a tissue independent of its local expression by altering systemic metabolism. Further studies on the gene regulation and function of transporters, as well as the interrelationship between transporters and phase I/II xenobiotic-metabolizing enzymes, will provide a complete framework for developing novel strategies to protect us from xenobiotic insults.

  3. Functional MRI in human motor control studies and clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Toma, Keiichiro [Kyoto Univ. (Japan). Graduate School of Medicine; Nakai, Toshiharu [Inst. of Biomedical Research and Innovation, Kobe (Japan)

    2002-07-01

    Functional magnetic resonance imaging (fMRI) has been a useful tool for the noninvasive mapping of brain function associated with various motor and cognitive tasks. Because fMRI is based on the blood oxygenation level dependent (BOLD) effect, it does not directly record neural activity. With the fMRI technique, distinguishing BOLD signals creased by cortical projection neurons from those created by intracortical neurons appears to be difficult. Two major experimental designs are used in fMRI studies: block designs and event-related designs. Block-designed fMRI presupposes the steady state of regional cerebral blood flow and has been applied to examinations of brain activation caused by tasks requiring sustained or repetitive movements. By contrast, the more recently developed event-related fMRI with time resolution of a few seconds allows the mapping of brain activation associated with a single movement according to the transient aspects of the hemodynamic response. Increasing evidence suggests that multiple motor areas are engaged in a networked manner to execute various motor acts. In order to understand functional brain maps, it is important that one understands sequential and parallel organizations of anatomical connections between multiple motor areas. In fMRI studies of complex motor tasks, elementary parameters such as movement length, force, velocity, acceleration and frequency should be controlled, because inconsistency in those parameters may alter the extent and intensity of motor cortical activation, confounding interpretation of the findings obtained. In addition to initiation of movements, termination of movements plays an important role in the successful achievement of complex movements. Brain areas exclusively related to the termination of movements have been, for the first time, uncovered with an event-related fMRI technique. We propose the application of fMRI to the elucidation of the pathophysiology of movement disorders, particularly dystonia

  4. Structural MRI studies of language function in the undamaged brain.

    Science.gov (United States)

    Richardson, Fiona M; Price, Cathy J

    2009-10-01

    In recent years, the demonstration that structural changes can occur in the human brain beyond those associated with development, ageing and neuropathology has revealed a new approach to studying the neural basis of behaviour. In this review paper, we focus on structural imaging studies of language that have utilised behavioural measures in order to investigate the neural correlates of language skills in the undamaged brain. We report studies that have used two different techniques: voxel-based morphometry of whole brain grey or white matter images and diffusion tensor imaging. At present, there are relatively few structural imaging studies of language. We group them into those that investigated (1) the perception of novel speech sounds, (2) the links between speech sounds and their meaning, (3) speech production, and (4) reading. We highlight the validity of the findings by comparing the results to those from functional imaging studies. Finally, we conclude by summarising the novel contribution of these studies to date and potential directions for future research.

  5. Compositional Study for Improving Wheat Flour with Functional Ingredients

    Directory of Open Access Journals (Sweden)

    Livia Apostol

    2015-11-01

    Full Text Available Helianthus tuberosus L. is cultivated widely across for its edible tuber. As a source of inulin with aperient, cholagogue and tonic effects, its tubers have been used for the treatment of diabetes. Also, the leaves of Helianthus tuberosus L. show antipyretic, analgesic effects and are therefore used for the treatment of bone fracture, skin wound and pain. The main aim of this study is to establish the optimum dose from rheological and nutritional point of view of Helianthus tuberosus L. tuber flour and leaves flour used as functional ingredient in bakery products industry. The types of mixtures of flours used in this study was: P1–100% wheat flour; P2-93% wheat flour + 7% Helianthus tuberosus (5% tuber + 2% leaves; P3-92% wheat flour + 8% Helianthus tuberosus (5% tuber + 3% leaves; P4- 90% wheat flour + 10%  Helianthus tuberosus (5% tuber + 5% leaves; P5 -100% Helianthus tuber; P6- Helianthus leaves. The potential functional of wheat flour enriched with the Helianthus tuberosus, in different proportions, was evaluated concerning chemical composition and rheological behaviour of the doughs. Adding of the Helianthus tuberosus L. tuber and leaves provoked an effect increasing the levels of inulin, minerals and fiber in wheat flour. The rheological properties of dough showed that P2, kept the rheological parameters for the technological behavior in order to obtain an acceptable quality of the bakery products. 

  6. Functional study of elafin cleaved by Pseudomonas aeruginosa metalloproteinases.

    LENUS (Irish Health Repository)

    Guyot, Nicolas

    2010-06-01

    Elafin is a 6-kDa innate immune protein present at several epithelial surfaces including the pulmonary epithelium. It is a canonical protease inhibitor of two neutrophil serine proteases [neutrophil elastase (NE) and proteinase 3] with the capacity to covalently bind extracellular matrix proteins by transglutamination. In addition to these properties, elafin also possesses antimicrobial and immunomodulatory activities. The aim of the present study was to investigate the effect of Pseudomonas aeruginosa proteases on elafin function. We found that P. aeruginosa PAO1-conditioned medium and two purified Pseudomonas metalloproteases, pseudolysin (elastase) and aeruginolysin (alkaline protease), are able to cleave recombinant elafin. Pseudolysin was shown to inactivate the anti-NE activity of elafin by cleaving its protease-binding loop. Interestingly, antibacterial properties of elafin against PAO1 were found to be unaffected after pseudolysin treatment. In contrast to pseudolysin, aeruginolysin failed to inactivate the inhibitory properties of elafin against NE. Aeruginolysin cleaves elafin at the amino-terminal Lys6-Gly7 peptide bond, resulting in a decreased ability to covalently bind purified fibronectin following transglutaminase activity. In conclusion, this study provides evidence that elafin is susceptible to proteolytic cleavage at alternative sites by P. aeruginosa metalloproteinases, which can affect different biological functions of elafin.

  7. Functional study of elafin cleaved by Pseudomonas aeruginosa metalloproteinases

    Science.gov (United States)

    Guyot, Nicolas; Bergsson, Gudmundur; Butler, Marcus W.; Greene, Catherine M.; Weldon, Sinead; Kessler, Efrat; Levine, Rodney L.; O’Neill, Shane J.; Taggart, Clifford C.; McElvaney, Noel G.

    2012-01-01

    Elafin is a 6 kDa innate immune protein present at several epithelial surfaces including the pulmonary epithelium. It is a canonical protease inhibitor of two neutrophil serine proteases (neutrophil elastase (NE) and proteinase 3) with the capacity to covalently bind extracellular matrix proteins by transglutamination. In addition to these properties, elafin also possesses antimicrobial and immunomodulatory activities. The aim of the present study was to investigate the effect of Pseudomonas aeruginosa proteases on elafin function. We found that P. aeruginosa PAO1-conditioned medium and two purified Pseudomonas metalloproteases, pseudolysin (elastase) and aeruginolysin (alkaline protease), were able to cleave recombinant elafin. Pseudolysin was shown to inactivate the anti-NE activity of elafin by cleaving its protease-binding loop. Interestingly, antibacterial properties of elafin against PAO1 were found to be unaffected after pseudolysin treatment. In contrast to pseudolysin, aeruginolysin failed to inactivate the inhibitory properties of elafin against NE. Aeruginolysin cleaved elafin at the amino-terminal Lys6-Gly7 peptide bond resulting in a decreased ability to covalently bind purified fibronectin following transglutaminase activity. In conclusion, this study provides evidences that elafin is susceptible to proteolytic cleavage at alternative sites by P. aeruginosa metalloproteinases, which can affect different biological functions of elafin. PMID:20370321

  8. Appreciation to Organic Agriculture Function: Case Study of Rice Farming

    Directory of Open Access Journals (Sweden)

    Tinjung Mary Prihtanti

    2016-10-01

    Full Text Available Agricultural activities are not only producing the visible (tangible output in the form of food but also the non-visible output (non-marketable goods/non-tangible services. Non-visible output refers to a multifunctionality to supply food to ensure the food sufficiency of farmer household and job opportunities at rural area. The article aims to compare the capability of organic rice farming to conventional, to ensure the food sufficiency of farmer household, the economic value of rice farming to produce food, and the economic estimation of rice farming to its function as an job opportunities. The data for the research is collected in Gentungan Village, Mojogedang District, Karanganyar Regency during the crop year of 2015. In order to study the differences of two rice farming systems, the total of 60 farmers, 30 farmers are dealing with organic farming and other 30 farmers from conventional farming, are subjected for the interview in this research. The results found that the food security of organic farming is higher than conventional farming. The organic rice farming gives the economic value as the food producing and the labor-absorbing function in the study area is higher than the  conventional farming.

  9. Radioisotope studies of mucociliary system function in otorhinolaryngology

    Energy Technology Data Exchange (ETDEWEB)

    De Rossi, G. [Istituto di Medicina Nucleare, Rome (Italy)

    1992-12-31

    An `excursus` on the Nuclear Medicine methods at present available for the study of mucociliary system function in otorhinolaryngology is reported. To this end, ostoscintigraphy and rhinosctinigraphy prove to be exquisitely sensitive techniques. Otoscintigraphy is useful for pre-operative studies in the patients who are planned to undergo tympanoplasty for dry tympanic perforations. Rhinoscintigraphy is regarded as the most affordable and sound method to evaluate mucociliary system function in rhinopathies. It is also suggested for the pre- and post-operative assessment of polypectomy. Hence, otorhinolaryngology radioisotope methods deserve to be extensively dealt with in Nuclear Medicine treatises. (orig.) [Deutsch] Der Autor gibt einen Ueberblick ueber nuklear-medizinische Verfahren, die heutzutage fuer funktionelle Untersuchungen des mukoziliaren Systems in der HNO-Heilkunde zur Verfuegung stehen. Die Otoszintigraphie sowie die Rhinoszintigraphie erweisen sich in diesem Zusammenhang als Methoden mit einer ueberaus hohen Empfindlichkeit. Bei Patienten, die wegen einer Trommelfellperforation zur Trommelfellplastik vorgesehen sind, bewaehrt sich die Otoszintigraphie fuer praeoperative Untersuchungen. Die Rhinoszintigraphie wird bei den unterschiedlichsten Nasenerkrankungen als die rationellste und wirksamste Methode zur funktionellen Beurteilung des mukoziliaren Systems angesehen. Darueber hinaus wird sie fuer die praeoperative und postoperative Untersuchung bei Polypenexstirpationen empfohlen. Deshalb sollte den Methoden der Radioisotopenuntersuchungen in der HNO-Heilkunde ein hoeherer Stellenwert eingeraeumt werden. (orig.)

  10. Functional phlebology. Phlebography, function studies, interventional radiology. Funktionelle Phlebologie. Phlebographie, Funktionstests, interventionelle Radiologie

    Energy Technology Data Exchange (ETDEWEB)

    Weber, J.; May, R.; Biland, L.; Endert, G.; Gottlob, R.; Justich, E.; Luebcke, P.; Mignon, G.; Moltz, L.; Partsch, H.; Petter, A.; Ritter, H.; Soerensen, R.; Widmer, L.K.; Widmer, M.T.; Zemp, E.

    1990-01-01

    The book presents a complete survey of the problems occurring in the venous system of the legs, pelvis, and abdomen. The material is arranged in the following main chapters: (1) Introduction to the phlebology of the low-pressure system in the lower part of the body; (2) Phlebographic methods; (3) Instrumented function studies and methods; (4) Pathologic findings; (5) Diagnostic methods and vein therapy; (6) Interventional radiology; (7) Expert opinions on venous lesions including insurance aspects. The first chapter encompasses a section briefly discussing the available instrumented diagnostic imaging methods. In view of the novel imaging methods, namely digital subtraction phlebology, sonography, CT and MRI, the classical phlebography remains the gold standard, so to speak: all currently available phlebographic methods for imaging the venes in the legs, pelvis and abdomen are explained and comparatively evaluated. Instrumented function tests such as Doppler effect ultrasound testing, plethysmography, peripheral and central phlebodynamometry (venous pressure measurement) are analysed for their diagnostic value and as alternative or supplementing techniques in comparison to phlebology. (orig./MG) With 843 figs., 101 tabs.

  11. Superconductivity in layered binary silicides: A density functional theory study

    Science.gov (United States)

    Flores-Livas, José A.; Debord, Régis; Botti, Silvana; San Miguel, Alfonso; Pailhès, Stéphane; Marques, Miguel A. L.

    2011-11-01

    A class of metal disilicides (of the form XSi2, where X is a divalent metal) crystallizes in the EuGe2 structure, formed by hexagonal corrugated silicon planes intercalated with metal atoms. These compounds are superconducting like other layered superconductors, such as MgB2. Moreover, their properties can be easily tuned either by external pressure or by negative chemical pressure (i.e., by changing the metal), which makes disilicides an ideal testbed to study superconductivity in layered systems. In view of this, we present an extensive density functional theory study of the electronic and phonon band structures as well as the electron-phonon interaction of metal disilicides. Our results explain the variation of the superconducting transition temperature with pressure and the species of the intercalating atom, and allow us to predict superconductivity for compounds not yet synthesized belonging to this family.

  12. Twenty years of protein interaction studies for biological function deciphering.

    Science.gov (United States)

    Legrain, Pierre; Rain, Jean-Christophe

    2014-07-31

    Intensive methodological developments and technology innovation have been devoted to protein-protein interaction studies over 20years. Genetic indirect assays and sophisticated large scale biochemical analyses have jointly contributed to the elucidation of protein-protein interactions, still with a lot of drawbacks despite heavy investment in human resources and technologies. With the most recent developments in mass spectrometry and computational tools for studying protein content of complex samples, the initial goal of deciphering molecular bases of biological functions is now within reach. Here, we described the various steps of this process and gave examples of key milestones in this scientific story line. This article is part of a Special Issue entitled: 20years of Proteomics in memory of Viatliano Pallini. Guest Editors: Luca Bini, Juan J. Calvete, Natacha Turck, Denis Hochstrasser and Jean-Charles Sanchez.

  13. Contrasting tropical estuarine ecosystem functioning and stability: A comparative study

    Science.gov (United States)

    Villanueva, Maria Ching

    2015-03-01

    A comparative study of the Sine-saloum (Senegal) and Gambia (The Gambia) estuaries was performed based on trophic model outputs that describe the system structure and functioning. These trophic models were constructed such as to differentiate main energetic flows in the systems and express how climate change may have impacted ecosystem resilience to change. Estuarine fish assemblages are highly resilient despite exposure to vast hydrodynamic variations and stress. Coupled with strong anthropogenic-driven stresses such as fisheries and climate change, ecosystems may undergo severe regime shifts that may weaken their resilience and stability. Taxonomically related and morphologically similar species do not necessarily play similar ecological roles in these two ecosystems. Biomass and production in the Sine-saloum are concentrated at trophic levels (TLs) 2 and 3, while for the Gambia, both are concentrated at TL3. Higher TL biomasses in Gambia compared to Sine-Saloum may be explained by the latter ecosystem being characterized by inverse hypersalinity. Higher TL of production in Sine-Saloum is due to higher exploitations compared to Gambia where fishing activities are still less developed. High production and consumption rates of some groups in both ecosystems indicate high system productivity. Elevated productivity may be due to higher abundance of juvenile fishes in most groups that utilize the latter as refuge and/or nursery zones. Both ecosystems are phytoplankton-driven. Differences in group trophic and ecological roles are mainly due to adaptive responses of these species to seasonal and long-term climate and anthropogenic stressors. System indicators suggest different levels of ecosystem resilience and stability as a function of biodiversity. Relevance of other observations on ecosystem functioning and indicators in relation to perturbation is discussed.

  14. PET functional volume delineation: a robustness and repeatability study

    Energy Technology Data Exchange (ETDEWEB)

    Hatt, Mathieu [CHU Morvan, INSERM, U650, LaTIM, Brest (France); CHU MORVAN, LaTIM, INSERM U650, Brest (France); Cheze-le Rest, Catherine [CHU Morvan, INSERM, U650, LaTIM, Brest (France); CHU, Academic Department of Nuclear Medicine, Brest (France); Albarghach, Nidal; Pradier, Olivier [CHU Morvan, INSERM, U650, LaTIM, Brest (France); CHU, Institute of Oncology, Brest (France); Visvikis, Dimitris [CHU Morvan, INSERM, U650, LaTIM, Brest (France)

    2011-04-15

    Current state-of-the-art algorithms for functional uptake volume segmentation in PET imaging consist of threshold-based approaches, whose parameters often require specific optimization for a given scanner and associated reconstruction algorithms. Different advanced image segmentation approaches previously proposed and extensively validated, such as among others fuzzy C-means (FCM) clustering, or fuzzy locally adaptive bayesian (FLAB) algorithm have the potential to improve the robustness of functional uptake volume measurements. The objective of this study was to investigate robustness and repeatability with respect to various scanner models, reconstruction algorithms and acquisition conditions. Robustness was evaluated using a series of IEC phantom acquisitions carried out on different PET/CT scanners (Philips Gemini and Gemini Time-of-Flight, Siemens Biograph and GE Discovery LS) with their associated reconstruction algorithms (RAMLA, TF MLEM, OSEM). A range of acquisition parameters (contrast, duration) and reconstruction parameters (voxel size) were considered for each scanner model, and the repeatability of each method was evaluated on simulated and clinical tumours and compared to manual delineation. For all the scanner models, acquisition parameters and reconstruction algorithms considered, the FLAB algorithm demonstrated higher robustness in delineation of the spheres with low mean errors (10%) and variability (5%), with respect to threshold-based methodologies and FCM. The repeatability provided by all segmentation algorithms considered was very high with a negligible variability of <5% in comparison to that associated with manual delineation (5-35%). The use of advanced image segmentation algorithms may not only allow high accuracy as previously demonstrated, but also provide a robust and repeatable tool to aid physicians as an initial guess in determining functional volumes in PET. (orig.)

  15. Study of structure function correlation of chemokine receptor CXCR4

    Institute of Scientific and Technical Information of China (English)

    ZHENG Hong; Stephen C PEIPER; ZHU Xi-hua

    2002-01-01

    Objective: To explore the correlation between structure domains and functions of chemokine receptor CXCR4. Methods: After the establishment of wild type chemokine receptor CXCR4 and CXCR2 expressing cell lines, 5 CXCR4/CXCR2 chimeras, 2 CXCR4 mutants were stably expressed on CHO cell line.Binding activities of all variants with the ligand, recombinant human SDF-1β, signal transduction ability after stimulation and their function as coreceptor for HIV-1 were studied with ligand-binding assay, Cytosensor/microphysiometry and cell-cell reporter gene fusion assay. Results: Among all 7 changed CXCR4 receptors, 3 chimeras (2444a, 4442, 4122), and 1 mutant (CXCR4-Tr) bond with SDF-1β in varying degrees, of which only 2444a totally and CXCR4-Tr partially maintain signaling. All changed receptors except for 4222 could act as coreceptors for HIV-1(LAI) in varying degrees. Conclusion: Several structure domains of CXCR4 are involved in the binding with SDF-1β, among which, N-terminal extracellular domain has high affinity of binding with SDF-1β, and the 3rd extracellular loop contributes to the binding, too. Although the C-terminal intracellular domain has no association with the maintenance of the overall structure of the receptor and ligand binding capability, the signaling is decreased when this domain is truncated. For CXCR4 signaling, not only is the conserved motif DRY box needed, but also the characterized conformation of the whole molecule must be formed when activation is required. There are some overlaps between SDF-1β binding domains and coreceptor function domains in molecular structure of CXCR4.

  16. Cohort description: The Danish study of Functional Disorders

    Science.gov (United States)

    Dantoft, Thomas Meinertz; Ebstrup, Jeanette Frost; Linneberg, Allan; Skovbjerg, Sine; Madsen, Anja Lykke; Mehlsen, Jesper; Brinth, Louise; Eplov, Lene Falgaard; Carstensen, Tina Wisbech; Schroder, Andreas; Fink, Per Klausen; Mortensen, Erik Lykke; Hansen, Torben; Pedersen, Oluf; Jørgensen, Torben

    2017-01-01

    The Danish study of Functional Disorders (DanFunD) cohort was initiated to outline the epidemiology of functional somatic syndromes (FSS) and is the first larger coordinated epidemiological study focusing exclusively on FSS. FSS are prevalent in all medical settings and can be defined as syndromes that, after appropriate medical assessment, cannot be explained in terms of a conventional medical or surgical disease. FSS are frequent and the clinical importance varies from vague symptoms to extreme disability. No well-described medical explanations exist for FSS, and how to delimit FSS remains a controversial topic. The specific aims with the cohort were to test delimitations of FSS, estimate prevalence and incidence rates, identify risk factors, delimitate the pathogenic pathways, and explore the consequences of FSS. The study population comprises a random sample of 9,656 men and women aged 18–76 years from the general population examined from 2011 to 2015. The survey comprises screening questionnaires for five types of FSS, ie, fibromyalgia, whiplash-associated disorder, multiple chemical sensitivity, irritable bowel syndrome, and chronic fatigue syndrome, and for the unifying diagnostic category of bodily distress syndrome. Additional data included a telephone-based diagnostic interview assessment for FSS, questionnaires on physical and mental health, personality traits, lifestyle, use of health care services and social factors, and a physical examination with measures of cardiorespiratory and morphological fitness, metabolic fitness, neck mobility, heart rate variability, and pain sensitivity. A biobank including serum, plasma, urine, DNA, and microbiome has been established, and central registry data from both responders and nonresponders are similarly available on morbidity, mortality, reimbursement of medicine, heath care use, and social factors. A complete 5-year follow-up is scheduled to take place from year 2017 to 2020, and further reexaminations will be

  17. The practicality of nanoceria-PAN-based (68)Ge/(68)Ga generator toward preparation of (68)Ga-labeled cyclic RGD dimer as a potential PET radiotracer for tumor imaging.

    Science.gov (United States)

    Chakraborty, Sudipta; Chakravarty, Rubel; Sarma, Haladhar D; Dash, Ashutosh; Pillai, M R A

    2013-02-01

    Cyclic RGD (Arg-Gly-Asp) peptides radiolabeled with (68)Ga have great potential for the early tumor detection and noninvasive monitoring of tumor metastasis and therapeutic response. Herein, the preparation of (68)Ga-labeled DOTA-E[c(RGDfK)](2) (DOTA=1,4,7,10-tetraazacylododecane-1,4,7,10-tetracetic acid; E=Glutamic acid; R=Arginine; G=Glycine; D=Aspartic acid; f=phenyl alanine; K=lysine) using (68)Ga directly eluted from a nanoceria-polyacrylonitrile (CeO(2)-PAN)-based (68)Ge/(68)Ga generator developed in-house was reported. The (68)Ga complex of DOTA-E[c(RGDfK)](2) was synthesized with >98% radiochemical purity by incubating 20 μg of the conjugate with (68)GaCl(3) (74-111 MBq) in acetate buffer (pH 3.5-4.0) at 90°C for 10 minutes. The complex exhibited excellent in vitro stability in 0.1 M EDTA solution at room temperature upto 1 hour studied (radiochemical purity: 98.0%). The biological efficacy of the radiolabeled conjugate was studied in C57/BL6 mice bearing melanoma tumors. The results of the biodistribution studies revealed significant tumor uptake (4.14±0.54%ID/g) within 10 minutes postinjection (p.i.), which increased further to 4.61±0.31%ID/g at 30 minutes p.i. The tumor-to-blood ratio was found to increase from 1.75±0.42 at 10 minutes p.i. to 2.25±0.20 at 60 minutes p.i., whereas the tumor-to-liver and tumor-to-muscle ratio between the same time points increased from 2.71±0.76 to 3.31±0.84 and 5.37±1.08 to 8.97±1.32, respectively. The study successfully demonstrated the preparation of (68)Ga-DOTA-E[c(RGDfK)](2) as a potential positron-emission tomography radiotracer for possible use in tumor imaging by using (68)Ga eluted from a reliable, easy-to-handle (68)Ge/(68)Ga generator developed in-house, without any postelution purification of (68)Ga.

  18. A snapshot of functional genetic studies in Medicago truncatula

    Directory of Open Access Journals (Sweden)

    Yun Kang

    2016-08-01

    Full Text Available In the current context of food security, increase of plant protein production in a sustainable manner represents one of the major challenges of agronomic research, which could be partially resolved by increased cultivation of legume crops. Medicago truncatula is now a well-established model for legume genomic and genetic studies. With the establishment of genomics tools and mutant populations in M. truncatula, it has become an important resource to answer some of the basic biological questions related to plant development and stress tolerance. This review has an objective to overview a decade of genetic studies in this model plant from generation of mutant populations to nowadays. To date, the three biological fields, which have been extensively studied in M. truncatula, are the symbiotic nitrogen fixation, the seed development, and the abiotic stress tolerance, due to their significant agronomic impacts. In this review, we summarize functional genetic studies related to these three major biological fields. We integrated analyses of a nearly exhaustive list of genes into their biological contexts in order to provide an overview of the forefront research advances in this important legume model plant.

  19. Khat Use and Neurobehavioral Functions: Suggestions for Future Studies

    Science.gov (United States)

    Hoffman, Richard; al’Absi, Mustafa

    2010-01-01

    Although there is a rich body of research available regarding the effect of acute and chronic khat dosing in animal models, research on the behavioral and cognitive effects of khat in human subjects is not extensive and several of the available studies have been done only in the context of observational and single-case studies. In light of the absence of a substantial literature on the neurobehavioral deficits associated with khat use and to provide a context that could be used to identify themes for future research we review previous research that has focused on other stimulant drugs. This review highlights multiple areas of neurocognitive deficit that have been identified in previous studies of individuals who have been chronic users of stimulants, such as amphetamines and methamphetamines. The review highlights a substantial body of evidence demonstrating a wide range of learning and memory impairments including deficits that persist during abstinence from active drug use. This review does not imply a similar khat effect, but due to some similarities pharmacologically between the active components of khat (cathinone and cathine) and amphetamines, future studies examining these same domains of cognitive functioning in chronic khat users and abstinent khat users appears to be warranted, if possible using some of the same or similar laboratory measures. PMID:20553832

  20. Study of the interconversion between viscoelastic behaviour functions of PMMA

    Science.gov (United States)

    Fernández, P.; Rodríguez, D.; Lamela, M. J.; Fernández-Canteli, A.

    2011-05-01

    The use of polymers and polymer-based composites in mechanical, civil and electronic engineering has been growing owing to advances in the technology of materials. The different applications and working conditions of these materials require knowledge about their viscoelastic material functions: relaxation modulus, compliance, complex modulus, etc. Interconversion between these functions may be required for different reasons such as the impossibility of direct experimentation under certain excitation conditions. In this work, a DMA is used to calculate the experimental viscoelastic functions of a linear viscoelastic material (PMMA). The same functions are estimated by interconversion methods and compared with experimental ones. The results show that the interconversion functions fit properly the experimental functions.

  1. Obesity, Cardiovascular Fitness, and Inhibition Function: An Electrophysiological Study

    Directory of Open Access Journals (Sweden)

    Tai-Fen Song

    2016-07-01

    Full Text Available The purpose of the present study was to examine how obesity and cardiovascular fitness are associated with the inhibition aspect of executive function from behavioral and electrophysiological perspectives. One hundred college students, aged 18 to 25 years, were categorized into four groups of equal size on the basis of body mass index and cardiovascular fitness: a normal-weight and high-fitness (NH group, an obese-weight and high-fitness (OH group, a normal-weight and low-fitness (NL group, and an obese-weight and low-fitness (OL group. Behavioral measures of response time and number of errors, as well as event-related potential (ERP measures of P3 and N1, were assessed during the Stroop Task. The results revealed that, in general, the NH group exhibited shorter response times and larger P3 amplitudes relative to the OH, NL, and OL groups, wherein the OL group exhibited the longest response time in the incongruent condition. No group differences in N1 indices were also revealed. These findings suggest that the status of being both normal weight and having high cardiovascular fitness is associated with better behavioral and later stages of electrophysiological indices of inhibition. However, these benefits in inhibition function would be lost in an individual who is obese or has low cardiovascular fitness, reflecting the importance keeping both normal weight and having high cardiovascular fitness.

  2. Study on Noncontact Pulmonary Function Test Using Pattern Light Projection

    Science.gov (United States)

    Aoki, Hirooki; Koshiji, Kohji

    The pulmonary function test by spirometer is generally conducted. The test subjects, especially children, women and older people, feel uncomfortable as the mouthpiece and nasal plug must be attached to the face of them. We have studied the nonrestraint pulmonary function test using the dot matrix pattern projection in order to decrease the burden to the examinee. In our proposed system, the pattern light projector illuminates the thorax with the dot matrix pattern light. And the CCD camera takes a series of images of the dot matrix pattern. The three dimensional shape of the thorax surface can be calculated by the distribution of light dots. And the respiratory waveform is calculated by the time-series change of the three dimensional shape. The respiratory waveform of our system was similar to one of spirometer. Therefore, we clarified that our proposed system can equivalently measure the respiration with spirometer. And we compared the volume change of the three dimensional shape calculated by our system with the expired tidal volume measured by the expiration gas analyzer. And we examined the relationship between the expired tidal volume and the volume change of the thorax surface.

  3. Genetic models for the study of luteinizing hormone receptor function

    Directory of Open Access Journals (Sweden)

    Prema eNarayan

    2015-09-01

    Full Text Available The luteinizing hormone/chorionic gonadotropin receptor, LHCGR, is essential for fertility in men and women. LHCGR binds luteinizing hormone (LH as well as the highly homologous chorionic gonadotropin (CG. Signaling from LHCGR is required for steroidogenesis and gametogenesis in males and females and for sexual differentiation in the male. The importance of LHCGR in reproductive physiology is underscored by the large number of naturally occurring inactivating and activating mutations in the receptor that result in reproductive disorders. Consequently, several genetically modified mouse models have been developed for the study of LHCGR function. They include targeted deletion of LH and LHCGR that mimic inactivating mutations in hormone and receptor, expression of a constitutively active mutant in LHCGR that mimics activating mutations associated with familial male-limited precocious puberty and transgenic models of LH and hCG overexpression. This review summarizes the salient findings from these models and their utility in understanding the physiological and pathological consequences of loss and gain of function in LHCGR signaling.

  4. Expression and Functional Studies on the Noncoding RNA, PRINS

    Directory of Open Access Journals (Sweden)

    Márta Széll

    2012-12-01

    Full Text Available PRINS, a noncoding RNA identified earlier by our research group, contributes to psoriasis susceptibility and cellular stress response. We have now studied the cellular and histological distribution of PRINS by using in situ hybridization and demonstrated variable expressions in different human tissues and a consistent staining pattern in epidermal keratinocytes and in vitro cultured keratinocytes. To identify the cellular function(s of PRINS, we searched for a direct interacting partner(s of this stress-induced molecule. In HaCaT and NHEK cell lysates, the protein proved to be nucleophosmin (NPM protein as a potential physical interactor with PRINS. Immunohistochemical experiments revealed an elevated expression of NPM in the dividing cells of the basal layers of psoriatic involved skin samples as compared with healthy and psoriatic uninvolved samples. Others have previously shown that NPM is a ubiquitously expressed nucleolar phosphoprotein which shuttles to the nucleoplasm after UV-B irradiation in fibroblasts and cancer cells. We detected a similar translocation of NPM in UV-B-irradiated cultured keratinocytes. The gene-specific silencing of PRINS resulted in the retention of NPM in the nucleolus of UV-B-irradiated keratinocytes; suggesting that PRINS may play a role in the NPM-mediated cellular stress response in the skin.

  5. Cross Functional Working and Concurrent Engineering – a UK Study

    Directory of Open Access Journals (Sweden)

    H. Williams

    2000-01-01

    Full Text Available This paper reports on the preliminary results of an investigative study into the implementation of concurrent engineering applied to new product development. Concurrent (or Simultaneous engineering is the term commonly given to creating new products using multi-disciplined teams of marketing, design, manufacturing and support functions together with supplier and customers. Such techniques have produced robust, low cost quality products in short concept to market times compared to traditional ones. The research investigated design management practice and performance in a number of organisations across a range of industrial sectors in the UK by means of a questionnaire survey. The results identify the current use of a variety of design practices and methodologies such as different organisational structures, the extent of cross-functional working, the use of design and phase reviews and the use of different technologies. They indicate that companies implementing CE are more successful in time to market performance than those who don’t implement CE. Factors most influencing the successful adoption of CE are design and phase reviews, and, to a lesser extent, the use of multifunctional teams and supplier partnerships.

  6. Study on functional relationships between ergonomics indexes of manual performance

    Science.gov (United States)

    Hu, Hui-Min; Ding, Li; Chen, Shou-Ping; Yang, Chun-Xin; Yuan, Xiu-Gan

    This paper investigates functional relationships between some of the key ergonomics indexes in manual performance, and attempts to condense the ergonomics appraisal indexes system and thus evaluate hand performance wearing EVA (extravehicular activity) glove, design and improve EVA glove's performance. Four types of ergonomics indexes were studied, i.e., dexterity, tactile sensibility (TS), strength and fatigue. Two test items of insert sticks into a holes-board (ISIHB) and nuts-bolts assembly task (NBAT) were used to measure dexterity, while shape discrimination (SD) was employed for TS, and grip force (GF) for strength and fatigue. The variables measured in this investigation included accomplishing time (AT) of ISIHB and NBAT, correct rate (CR) of SD, maximal grip force (MGF), instant grip force (IGF) and endurance time of grip force (ETGF). Experiments were conducted on 31 undergraduates (eight female and 23 male) with two experiment conditions of bare-hand group and gloved hand group. Results demonstrated that dexterity and TS performance of gloved hand group declined significantly compared with those of bare-hand group (p0.05). Four effective functional relationships were developed between four pairs of ergonomics indexes in bare-hand group. In gloved hand group, in addition to above-mentioned four pairs of relationships, another formula was found, which was y^=0.02061+0.01233x ( p<0.01, dexterity and TS).

  7. Combining taxonomy and function in the study of stream macroinvertebrates

    Directory of Open Access Journals (Sweden)

    Kenneth W. Cummins

    2016-03-01

    Full Text Available Over the last fifty years, research on freshwater macroinvertebrates has been driven largely by the state of the taxonomy of these animals. In the great majority of studies conducted during the 2000s macroinvertebrates have been operationally defined by investigators as invertebrates retained by a 250 μ mesh in field sampling devices. Significant advances have been and continue to be made in developing ever more refined keys to macroinvertebrate groups. The analysis by function is a viable alternative when advances in macroinvertebrate ecological research is restricted by the level of detail in identifications. Focus on function, namely adaptations of macroinvertebrates to habitats and the utilization of food resources, has facilitated ecological evaluation of freshwater ecosystems (Functional feeding groups; FFG. As the great stream ecologist Noel Hynes observed, aquatic insects around the world exhibit similar morphologies and behaviors, even though they are in very different taxonomic groups. This is the basis for the FFG analysis that was initially developed in the early 1970s. FFG analysis applies taxonomy only to the level of detail that allows assignment to one of six FFG categories: scrapers adapted to feed on periphyton, detrital shredders adapted to feed on coarse (CPOM riparian-derived plant litter that has been colonized by microbes, herbivore shredders that feed on live, rooted aquatic vascular plants, filtering collectors adapted to remove fine particle detritus (FPOM from the water column, gathering collectors adapted to feed on FPOM where it is deposited on surfaces or in crevices in the sediments, and predators that capture live prey. The interacting roles of these FFGs in stream ecosystems were originally depicted in a conceptual model. Thus, there are a limited number of adaptations exhibited by stream macroinvertebrates that exploit these habitats and food resources. This accounts for the wide range of macroinvertebrate taxa

  8. First-principle study of nanostructures of functionalized graphene

    Indian Academy of Sciences (India)

    Naveen Kumar; Jyoti Dhar Sharma; P K Ahluwalia

    2014-06-01

    We present first-principle calculations of 2D nanostructures of graphene functionalized with hydrogen and fluorine, respectively, in chair conformation. The partial density of states, band structure, binding energy and transverse displacement of C atoms due to functionalization (buckling) have been calculated within the framework of density functional theory as implemented in the SIESTA code. The variation in band gap and binding energy per add atom have been plotted against the number of add atoms, as the number of add atoms are incremented one by one. In all, 37 nanostructures with 18C atoms, 3 × 3 × 1 (i.e., the unit cell is repeated three times along -axis and three times along -axis) supercell, have been studied. The variation in C–C, C–H and C–F bond lengths and transverse displacement of C atoms (due to increase in add atoms) have been tabulated. A large amount of buckling is observed in the carbon lattice, 0.0053–0.7487 Å, due to hydrogenation and 0.0002–0.5379 Å, due to fluorination. As the number of add atoms (hydrogen or fluorine) is increased, a variation in the band gap is observed around the Fermi energy, resulting in change in behaviour of nanostructure from conductor to semiconductor/insulator. The binding energy per add atom increases with the increase in the number of add atoms. The nanostructures with 18C+18H and 18C+18F have maximum band gap of 4.98 eV and 3.64 eV, respectively, and binding energy per add atom –3.7562 eV and –3.3507 eV, respectively. Thus, these nanostructures are stable and are wide band-gap semiconductors, whereas the nanostructures with 18C+2H, 18C+4H, 18C+4F, 18C+8F, 18C+10F and 18C+10H atoms are small band-gap semiconductors with the band gap lying between 0.14 eV and 1.72 eV. Fluorine being more electronegative than hydrogen, the impact of electronegativity on band gap, binding energy and bond length is visible. It is also clear that it is possible to tune the electronic properties of functionalized

  9. Using functional genomics to study PINK1 and metabolic physiology

    DEFF Research Database (Denmark)

    Scheele, Camilla; Larsson, Ola; Timmons, James A

    2009-01-01

    in mammalian cells. Use of such technologies, inspired by nature's endogenous RNAi mechanism-microRNA targeting, comes with significant caveats. While the discipline of Pharmacology taught us last century that inhibitor action specificity is dependent on the concentration used, these experiences have been......Genome sequencing projects have provided the substrate for an unimaginable number of biological experiments. Further, genomic technologies such as microarrays and quantitative and exquisitely sensitive techniques such as real-time quantitative polymerase chain reaction have made it possible...... or experimental control. Thus, functional genomics is now being applied to study metabolic physiology with varying degrees of success. From the genome sequencing projects we also have the information needed to design chemical tools that can knock down a gene transcript, even distinguishing between splice variants...

  10. Study of spontaneous fission lifetimes using nuclear density functional theory

    Directory of Open Access Journals (Sweden)

    Sadhukhan Jhilam

    2013-12-01

    Full Text Available The spontaneous fission lifetimes have been studied microscopically by minimizing the collective action integral in a two-dimensional collective space of quadrupole moments (Q20, Q22 representing elongation and triaxiality. The microscopic collective potential and inertia tensor are obtained by solving the self-consistent Hartree-Fock-Bogoliubov (HFB equations with the Skyrme energy density functional and mixed pairing interaction. The mass tensor is computed within the perturbative Adiabatic Time-Dependent HFB (ATDHFB approach in the cranking approximation. The dynamic fission trajectories have been obtained by minimizing the collective action using two different numerical techniques. The values of spontaneous fission lifetimes obtained in this way are compared with the static results.

  11. Density Functional Studies of Methanol Decomposition on Subnanometer Pd Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Mehmood, Faisal; Greeley, Jeffrey P.; Curtiss, Larry A.

    2009-12-31

    A density functional theory study of the decomposition of methanol on subnanometer palladium clusters (primarily Pd4) is presented. Methanol dehydrogenation through C-H bond breaking to form hydroxymethyl (CH2OH) as the initial step, followed by steps involving formation of hydroxymethylene (CHOH), formyl (CHO), and carbon monoxide (CO), is found to be the most favorable reaction pathway. A competing dehydrogenation pathway with O-H bond breaking as the first step, followed by formation of methoxy (CH3O) and formaldehyde (CH2O), is slightly less favorable. In contrast, pathways involving C-O bond cleavage are much less energetically favorable, and no feasible pathways involving C-O bond formation to yield dimethyl ether (CH3OCH3) are found. Comparisons of the results are made with methanol decomposition products adsorbed on more extended Pd surfaces; all reaction intermediates are found to bind slightly more strongly to the clusters than to the surfaces.

  12. A preliminary study of cryosphere service function and value evaluation

    Institute of Scientific and Technical Information of China (English)

    XIAO Cun-De; WANG Shi-Jin; QIN Da-He

    2015-01-01

    Cryosphere science research and development (R&D) has been strongly committed to public service, integrating natural sciences with socioeconomic impacts. Owing to the current shift from purely natural cryosphere scientific research to linking cryosphere science with so-cioeconomic and cultural science, cross-disciplinary research in this field is emerging, which advocates future cryosphere science research in this field. Utilizing the cryosphere service function (CSF), this study establishes CSF and its value evaluation system. Cryosphere service valuation can benefit the decisionmakers' and public's awareness of environmental protection. Implementing sustainable CSF utilization strategies and macroeconomic policymaking for global environmental protection will have profound and practical significance as well as avoid environmental degradation while pursuing short-term economic profits and achieving rapid economic development.

  13. Cohort description: The Danish study of Functional Disorders

    Directory of Open Access Journals (Sweden)

    Dantoft TM

    2017-02-01

    Full Text Available Thomas Meinertz Dantoft,1 Jeanette Frost Ebstrup,1 Allan Linneberg,1–3 Sine Skovbjerg,1 Anja Lykke Madsen,1 Jesper Mehlsen,4 Louise Brinth,4 Lene Falgaard Eplov,5 Tina Wisbech Carstensen,6,7 Andreas Schroder,6,7 Per Klausen Fink,6,7 Erik Lykke Mortensen,8 Torben Hansen,9 Oluf Pedersen,9 Torben Jørgensen1,10,11 1Research Centre for Prevention and Health, The Capital Region of Denmark, Glostrup, 2Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 3Department of Clinical Experimental Research, Rigshospitalet, Glostrup, 4Coordinating Research Centre, Bispebjerg and Frederiksberg Hospital, Frederiksberg, 5Mental Health Centre Copenhagen, Research Unit, Mental Health Services, Capital Region of Denmark, Copenhagen, 6The Research Clinic for Functional Disorders and Psychosomatics, Aarhus University Hospital, 7Faculty of Health Sciences, University of Aarhus, Aarhus, 8Department of Public Health and Center for Healthy Aging, 9Novo Nordisk Foundation Center for Basic Metabolic Research, 10Department of Public Health, Faculty of Health and Medical Sciences, University of Copenhagen, 11Faculty of Medicine, Aalborg University, Aalborg, Denmark Abstract: The Danish study of Functional Disorders (DanFunD cohort was initiated to outline the epidemiology of functional somatic syndromes (FSS and is the first larger coordinated epidemiological study focusing exclusively on FSS. FSS are prevalent in all medical settings and can be defined as syndromes that, after appropriate medical assessment, cannot be explained in terms of a conventional medical or surgical disease. FSS are frequent and the clinical importance varies from vague symptoms to extreme disability. No well-described medical explanations exist for FSS, and how to delimit FSS remains a controversial topic. The specific aims with the cohort were to test delimitations of FSS, estimate prevalence and incidence rates, identify risk factors

  14. Indonesian Interrogative Sentences: a Study of Forms and Functions

    Directory of Open Access Journals (Sweden)

    Lindawati

    2016-10-01

    Full Text Available This study examines Indonesian interrogative sentence problems by focusing on issues of forms and functions. The data used in this analysis are interrogative sentences in Indonesian language that are currently used in oral and in interethnic communication. This study used a pragmatic approach. Listening while observing (metode simak is used at the stage of data collection. In the analysis phase, a structural analysis is used for the discussion of issues related to the form, and a contextual analysis method is used for the discussion of issues related to the function of interrogative sentence. The report was presented verbally. From the research, it can be formulated that interrogative sentences forming elements are either supra-segmental elements or segmental elements. Supra-segmental elements are intonation, and segmental elements are words, phrases, and particles. The elements were added to a clause to be the base of an interrogative sentence. Based on the response form provided by what the opponents said, interrogative sentences are grouped on the yes-no and information interrogative sentences. Yes-no interrogative sentences require an answer that contains a justification or denial of what is stated on the clause that is the basis for the formation of interrogative sentences. Information interrogative sentences require an answer in the form of explanation. In communications, interrogative sentences are uttered not only to ask something, but they are also used to express a variety of speech act. Speech act that can be expressed by the interrogative sentences of Indonesian language are representative, directive, commissive, and expressive. Interrogative sentences are sometimes used in order to speak indirectly (indirect speech to maintain politeness or otherwise stated expressive rudely.

  15. Statistical Study of Turbulence: Spectral Functions and Correlation Coefficients

    Science.gov (United States)

    Frenkiel, Francois N.

    1958-01-01

    In reading the publications on turbulence of different authors, one often runs the risk of confusing the various correlation coefficients and turbulence spectra. We have made a point of defining, by appropriate concepts, the differences which exist between these functions. Besides, we introduce in the symbols a few new characteristics of turbulence. In the first chapter, we study some relations between the correlation coefficients and the different turbulence spectra. Certain relations are given by means of demonstrations which could be called intuitive rather than mathematical. In this way we demonstrate that the correlation coefficients between the simultaneous turbulent velocities at two points are identical, whether studied in Lagrange's or in Euler's systems. We then consider new spectra of turbulence, obtained by study of the simultaneous velocities along a straight line of given direction. We determine some relations between these spectra and the correlation coefficients. Examining the relation between the spectrum of the turbulence measured at a fixed point and the longitudinal-correlation curve given by G. I. Taylor, we find that this equation is exact only when the coefficient is very small.

  16. Dicentric chromosomes: unique models to study centromere function and inactivation.

    Science.gov (United States)

    Stimpson, Kaitlin M; Matheny, Justyne E; Sullivan, Beth A

    2012-07-01

    Dicentric chromosomes are products of genome rearrangement that place two centromeres on the same chromosome. Depending on the organism, dicentric stability varies after formation. In humans, dicentrics occur naturally in a substantial portion of the population and usually segregate successfully in mitosis and meiosis. Their stability has been attributed to inactivation of one of the two centromeres, creating a functionally monocentric chromosome that can segregate normally during cell division. The molecular basis for centromere inactivation is not well understood, although studies in model organisms and in humans suggest that genomic and epigenetic mechanisms can be involved. Furthermore, constitutional dicentric chromosomes ascertained in patients presumably represent the most stable chromosomes, so the spectrum of dicentric fates, if it exists, is not entirely clear. Studies of engineered or induced dicentrics in budding yeast and plants have provided significant insight into the fate of dicentric chromosomes. And, more recently, studies have shown that dicentrics in humans can also undergo multiple fates after formation. Here, we discuss current experimental evidence from various organisms that has deepened our understanding of dicentric behavior and the intriguingly complex process of centromere inactivation.

  17. Functional

    Directory of Open Access Journals (Sweden)

    Fedoua Gandia

    2014-07-01

    Full Text Available The study was carried out to investigate the effects of inhaled Mg alone and associated with F in the treatment of bronchial hyperresponsiveness. 43 male Wistar rats were randomly divided into four groups and exposed to inhaled NaCl 0.9%, MeCh, MgSO4 and MgF2. Pulmonary changes were assessed by means of functional tests and quantitative histological examination of lungs and trachea. Results revealed that delivery of inhaled Mg associated with F led to a significant decrease of total lung resistance better than inhaled Mg alone (p < 0.05. Histological examinations illustrated that inhaled Mg associated with F markedly suppressed muscular hypertrophy (p = 0.034 and bronchoconstriction (p = 0.006 in MeCh treated rats better than inhaled Mg alone. No histological changes were found in the trachea. This study showed that inhaled Mg associated with F attenuated the main principle of the central components of changes in MeCh provoked experimental asthma better than inhaled Mg alone, potentially providing a new therapeutic approach against asthma.

  18. The study of virus structure and function: a personal history

    Science.gov (United States)

    Rossmann, Michael G.

    2014-09-01

    I describe my gradually evolving role as a scientist from my birth in Frankfurt (Germany) to my education in the UK, my post-doc years and my experiences as an independent investigator at Purdue University1. I discuss the significance of my post-doctoral work in Minnesota where I had my first encounter with an electronic computer and subsequently in Cambridge where I participated in the first structure determination of proteins. After six years back in England my family moved to Indiana (USA) where my home remains to this day. At Purdue University I first studied the structure of enzymes and in the process I discovered the organization and slow evolution of protein domains, each with a specific function. With this success I started what had been on my mind already for a long time, namely the structural analysis of viruses. Initially we studied plant viruses but then switched to small RNA animal viruses, discovering that some plant and animal RNA viruses have closely similar structures and therefore presumably had a common evolutionary origin. Next I became interested in somewhat larger viruses that had lipid membrane envelopes. In turn that has led to the study of very large dsDNA viruses as big as small bacteria as well as studies of bacterial viruses that require complex molecular motors for different parts of their life cycle. While developing crystallographic techniques for the study of viruses it has become progressively more apparent that electron microscopy is an important new tool that is likely to eclipse x-ray crystallography in the next decade.

  19. Receiver function study in northern Sumatra and the Malaysian peninsula

    Science.gov (United States)

    Kieling, Katrin; Roessler, Dirk; Krueger, Frank

    2011-04-01

    In this receiver function study, we investigate the structure of the crust beneath six seismic broadband stations close to the Sunda Arc formed by subduction of the Indo-Australian under the Sunda plate. We apply three different methods to analyse receiver functions at single stations. A recently developed algorithm determines absolute shear-wave velocities from observed frequency-dependent apparent incidence angles of P waves. Using waveform inversion of receiver functions and a modified Zhu and Kanamori algorithm, properties of discontinuities such as depth, velocity contrast, and sharpness are determined. The combination of the methods leads to robust results. The approach is validated by synthetic tests. Stations located on Malaysia show high-shear-wave velocities ( V S) near the surface in the range of 3.4-3.6 km s - 1 attributed to crystalline rocks and 3.6-4.0 km s - 1 in the lower crust. Upper and lower crust are clearly separated, the Moho is found at normal depths of 30-34 km where it forms a sharp discontinuity at station KUM or a gradient at stations IPM and KOM. For stations close to the subduction zone (BSI, GSI and PSI) complexity within the crust is high. Near the surface low V S of 2.6-2.9 km s - 1 indicate sediment layers. High V S of 4.2 km s - 1 are found at depth greater than 6 and 2 km at BSI and PSI, respectively. There, the Moho is located at 37 and 40 km depth. At station GSI, situated closest to the trench, the subducting slab is imaged as a north-east dipping structure separated from the sediment layer by a 10 km wide gradient in V S between 10 and 20 km depth. Within the subducting slab V S ≈ 4.7 km s - 1. At station BSI, the subducting slab is found at depth between 90 and 110 km dipping 20° ± 8° in approximately N 60° E. A velocity increase in similar depth is indicated at station PSI, however no evidence for a dipping layer is found.

  20. A Density Functional Study of Bare and Hydrogenated Platinum Clusters

    CERN Document Server

    Sebetci, A

    2006-01-01

    We perform density functional theory calculations using Gaussian atomic-orbital methods within the generalized gradient approximation for the exchange and correlation to study the interactions in the bare and hydrogenated platinum clusters. The minimum-energy structures, binding energies, relative stabilities, vibrational frequencies and the highest occupied and lowest unoccupied molecular-orbital gaps of Pt_nH_m (n=1-5, m=0-2) clusters are calculated and compared with previously studied pure platinum and hydrogenated platinum clusters. We investigate any magic behavior in hydrogenated platinum clusters and find that Pt_4H_2 is more stable than its neighboring sizes. Our results do not agree with a previous conclusion that 3D geometries of Pt tetramer and pentamer are unfavored. On the contrary, the lowest energy structure of Pt_4 is found to be a distorted tetrahedron and that of Pt_5 is found to be a bridge site capped tetrahedron which is a new global minimum for Pt_5 cluster. The successive addition of H ...

  1. STUDY OF CARDIOVASCULAR AUTONOMIC FUNCTIONS IN CONGENITALLY DEAF CHILDREN

    Directory of Open Access Journals (Sweden)

    Veena

    2015-06-01

    Full Text Available BACKGROUND : Majority of congenitally deaf children are at risk of cardiac abnormalities in the form of long QT syndrome which could be due to an intracardiac abnormality or autonomic dysfunction. Altered sympathetic/parasympathetic balance as a result of the absence of auditory stimuli on the autonomic nervous system results in lower mean heart rate in congenitally deaf children. OBJECTIVES: To evaluate whether the cardiovascular autonomic functions are altered in congenitally deaf children. MATERIALS AND METHODS: 30 congenitally deaf children aged between 14 - 18 yrs and 30 age matched controls were included for the study. Parasympathetic activity was assessed by observing the heart rate changes to immediate standing from lying down position, heart rate changes during deep breathing and heart rate changes during valsalva maneuver. Sympathetic activity was assessed by observing blood pressure changes on immediate standing from lying down position and blood pressure changes during sustained hand grip. RESULTS: The results of the present study showed statistically significant decrease in the systolic blood pressure in response to immediate standing among congenitally deaf children suggestive of sympathetic imbalance and an early stage of autonomic dysfunction.

  2. Metal catalyzed ethylene epoxidation: A comparative density functional theory study

    Institute of Scientific and Technical Information of China (English)

    Ruipeng Ren; Yongkang Lü; Xianyong Pang; Guichang Wang

    2011-01-01

    Ethylene epoxidation on Ag(111), Pt(111), Rh(111) and Mo(100) has been studied by density functional theory (DFT) calculations. The results show that the adsorption energies of possible adsorbed species involved in the ethylene epoxidation increase in the order: Ag<Pt<Rh<Mo, and the activation energies of the formation of epoxide (EtO) and acetaldehyde (Ac) follow the same order. Moreover, it is found that the smallest difference in the activation energies between EtO formation and Ac formation is shown on Ag. These results indicate that the metallic Ag shows the highest between activity and selectivity for ethylene epoxidation among the studied metal surfaces. Perhaps, the stability of OMME intermediate is the crucial factor in controlling the activity and selectivity. And the stronger the binding of OMME, the lower the activity and selectivity are. In addition, the relationships between the reaction enthalpy and activation energy on these four metal surfaces are investigated,and it is found that such a correlation is only applied for OMME(a) → EtO(a) and OMME(a) → Ac(a), while invalid for the case of C2H4(a) +O(a) → OMME(a).

  3. Facilitating Structure-Function Studies of CFTR Modulator Sites with Efficiencies in Mutagenesis and Functional Screening.

    Science.gov (United States)

    Molinski, Steven V; Ahmadi, Saumel; Hung, Maurita; Bear, Christine E

    2015-12-01

    There are nearly 2000 mutations in the CFTR gene associated with cystic fibrosis disease, and to date, the only approved drug, Kalydeco, has been effective in rescuing the functional expression of a small subset of these mutant proteins with defects in channel activation. However, there is currently an urgent need to assess other mutations for possible rescue by Kalydeco, and further, definition of the binding site of such modulators on CFTR would enhance our understanding of the mechanism of action of such therapeutics. Here, we describe a simple and rapid one-step PCR-based site-directed mutagenesis method to generate mutations in the CFTR gene. This method was used to generate CFTR mutants bearing deletions (p.Gln2_Trp846del, p.Ser700_Asp835del, p.Ile1234_Arg1239del) and truncation with polyhistidine tag insertion (p.Glu1172-3Gly-6-His*), which either recapitulate a disease phenotype or render tools for modulator binding site identification, with subsequent evaluation of drug responses using a high-throughput (384-well) membrane potential-sensitive fluorescence assay of CFTR channel activity within a 1 wk time frame. This proof-of-concept study shows that these methods enable rapid and quantitative comparison of multiple CFTR mutants to emerging drugs, facilitating future large-scale efforts to stratify mutants according to their "theratype" or most promising targeted therapy.

  4. In vivo evaluation of [{sup 11}C]N-(2-chloro-5-thiomethylphenyl)-N'- (3-methoxy-phenyl)-N'-methylguanidine ([{sup 11}C]GMOM) as a potential PET radiotracer for the PCP/NMDA receptor

    Energy Technology Data Exchange (ETDEWEB)

    Waterhouse, Rikki N. E-mail: rnw7@columbia.edu; Slifstein, Mark; Dumont, Filip; Zhao Jun; Chang, Raymond C.; Sudo, Yasuhiko; Sultana, Abida; Balter, Andrew; Laruelle, Marc

    2004-10-01

    The development of imaging methods to measure changes in NMDA ion channel activation would provide a powerful means to probe the mechanisms of drugs and device based treatments (e.g., ECT) thought to alter glutamate neurotransmission. To provide a potential NMDA/PCP receptor PET tracer, we synthesized the radioligand [{sup 11}C]GMOM (K{sub i} = 5.2 {+-}0.3 nM; log P = 2.34) and evaluated this ligand in vivo in awake male rats and isoflurane anesthetized baboons. In rats, the regional brain uptake of [{sup 11}C]GMOM ranged from 0.75{+-}0.13% ID/g in the medulla and pons to 1.15{+-}0.17% ID/g in the occipital cortex. MK801 (1 mg/kg i.v.) significantly reduced (24-28%) [{sup 11}C]GMOM uptake in all regions. D-serine (10 mg/kg i.v.) increased [{sup 11}C]GMOM %ID/g values in all regions (10-24%) reaching significance in the frontal cortex and cerebellum only. The NR2B ligand RO 25-6981 (10 mg/kg i.v.) reduced [{sup 11}C]GMOM uptake significantly (24-38%) in all regions except for the cerebellum and striatum. Blood activity was 0.11{+-}0.03 %ID/g in the controls group and did not vary significantly across groups. PET imaging in isoflurane-anesthetized baboons with high specific activity [{sup 11}C]GMOM provided fairly uniform regional brain distribution volume (V{sub T}) values (12.8-17.1 ml g{sup -1}). MK801 (0.5 mg/kg, i.v., n = 1, and 1.0 mg/kg, i.v., n = 1) did not significantly alter regional V{sub T} values, indicating a lack of saturable binding. However, the potential confounding effects associated with ketamine induction of anesthesia along with isoflurane maintenance must be considered because both agents are known to reduce NMDA ion channel activation. Future and carefully designed studies, presumably utilizing an optimized NMDA/PCP site tracer, will be carried out to further explore these hypotheses. We conclude that, even though [{sup 11}C]GMOM is not an optimized PCP site radiotracer, its binding is altered in vivo in awake rats as expected by modulation of

  5. Reduced medial temporal lobe functionality in stroke patients: a functional magnetic resonance imaging study.

    Science.gov (United States)

    Snaphaan, Liselore; Rijpkema, Mark; van Uden, Inge; Fernández, Guillén; de Leeuw, Frank-Erik

    2009-07-01

    Stroke is a leading cause of disability, not only because of motor limitations, but also because of the frequent occurrence of post-stroke cognitive impairment. This is illustrated by the fact that the risk of post-stroke dementia is reportedly higher than a recurrent stroke. The loss of subcortical and cortical functions in the post-stroke cognitive dysfunction spectrum is usually well explained by the size and location of the infarction. However, this does not apply for post-stroke memory dysfunction (especially episodic memory dysfunction), as there is almost never an infarction in the medial temporal lobe. Involvement of the medial temporal lobe in post-stroke memory dysfunction seems likely since this structure is essential for memory encoding and retrieval. For a proper episodic memory function, the medial temporal lobe depends on intact connections with virtually the whole brain. Disconnection from other brain areas due to the infarction could lead to a reduced medial temporal lobe function and the attendant reduced episodic memory function. We investigated medial temporal lobe functionality in 28 'first-ever' stroke patients and 22 healthy controls with the aid of functional magnetic resonance imaging. Stroke patients with a reduced episodic memory function 6-8 weeks after infarction had reduced medial temporal lobe functionality. Post-stroke reduced medial temporal lobe functionality may be responsible for the frequent observation of impaired post-stroke episodic memory function. Insight into this mechanism could be helpful in identifying which stroke patients may be at increased risk for developing post-stroke dementia and those who could benefit from early cognitive rehabilitation.

  6. Imaging the impact of cyclosporin A and dipyridamole on P-glycoprotein (ABCB1) function at the blood-brain barrier: A [(11)C]-N-desmethyl-loperamide PET study in nonhuman primates.

    Science.gov (United States)

    Damont, Annelaure; Goutal, Sébastien; Auvity, Sylvain; Valette, Héric; Kuhnast, Bertrand; Saba, Wadad; Tournier, Nicolas

    2016-08-25

    Cyclosporin A (CsA) and dipyridamole (DPy) are potent inhibitors of the P-glycoprotein (P-gp; ABCB1) in vitro. Their efficacy at inhibiting P-gp at the blood-brain barrier (BBB) is difficult to predict. Efficient and readily available (i.e. marketed) P-gp inhibitors are needed as probes to investigate the role of P-gp at the human BBB. In this study, the P-gp inhibition potency at the BBB of therapeutic doses of CsA or DPy was evaluated in baboons using Positron Emission Tomography (PET) imaging with [(11)C]-N-desmethyl-loperamide ([(11)C]dLop), a radiolabeled P-gp substrate. The preparation of dLop as authentic standard and [(11)C]dLop as radiotracer were revisited so as to improve their production yields. [(11)C]dLop PET imaging was performed in the absence (n=3, baseline condition) and the presence of CsA (15mg/kg/h i.v., n=3). Three animals were injected with i.v. DPy at either 0.56 or 0.96 or 2mg/kg (n=1), corresponding to the usual, maximal and twice the maximal dose in patients, respectively, administered immediately before PET. [(11)C]dLop brain kinetics as well as [(11)C]dLop kinetics and radiometabolites in arterial plasma were measured to calculate [(11)C]dLop area-under the time-activity curve from 10 to 30min in the brain (AUCbrain) and in plasma (AUCplasma). [(11)C]dLop brain uptake was described by AUCR=AUCbrain/AUCplasma. CsA as well as DPy did not measurably influence [(11)C]dLop plasma kinetics and metabolism. Baseline AUCR (0.85±0.29) was significantly enhanced in the presence of CsA (AUCR=10.8±3.6). Injection of pharmacologic dose of DPy did not enhance [(11)C]dLop brain distribution with AUCR being 1.2, 0.9 and 1.1 after administration of 0.56, 0.96 and 2mg/kg DPy doses, respectively. We used [(11)C]dLop PET imaging in baboons, a relevant in vivo model of P-gp function at the BBB, to show the P-gp inhibition potency of therapeutic dose CsA. Despite in vitro P-gp inhibition potency, usual doses DPy are not likely to inhibit P-gp function at

  7. Functional magnetic resonance imaging study of writer's cramp

    Institute of Scientific and Technical Information of China (English)

    HU Xing-yue; WANG Li; LIU Hai; ZHANG Shi-zheng

    2006-01-01

    Background Writer's cramp is a type of task specific idiopathic focal dystonia and has an incompletelyunderstood pathophysiology. The present study utilized functional magnetic resonance imaging (fMRI) toinvestigate what type of brain activity correlates with writer's cramp and its physiological mechanism.Methods Ten patients with writer's cramp were age and gender matched with ten healthy control subjects in ablock design. Subjects were scanned by fMRI while performing three consecutive, visually instructive, tasks withMR Vision 2000: (1) suppositional writing, (2) writing with finger and (3) writing with a pencil. Data wasanalysed using AFNI software for groups of patients and controls.Results The patients with writer's cramp showed significant activations of contralateral basal ganglion(especially the putamen), motor cortex (primary sensorimotor cortex, supplementary motor cortex, premotorcortex) and ipsilateral cerebellar hemisphere in writing with a pencil compared with controls; whereas there wasno obvious difference between patients and controls during writing with finger. Furthermore, these differencesexist in the subtractive activated maps for "writing with a pencil" minus "writing with finger" of patients, whenthe activation of subcortical area and insula in controls disappeared.Conclusions Abnormal activations of contralateral basal ganglion, motor cortex and ipsilateral cerebellarhemisphere of the patients with writer's cramp suggest dysfunction of basal ganglion and subcortical-corticalloop might play a pathophysiological role in writer's cramp.

  8. Density functional theory study of phase IV of solid hydrogen

    Science.gov (United States)

    Pickard, Chris J.; Martinez-Canales, Miguel; Needs, Richard J.

    2012-06-01

    We have studied solid hydrogen up to pressures of 300 GPa and temperatures of 350 K using density functional theory methods and have found “mixed structures” that are more stable than those predicted earlier. Mixed structures consist of alternate layers of strongly bonded molecules and weakly bonded graphene-like sheets. Quasiharmonic vibrational calculations show that mixed structures are the most stable at room temperature over the pressure range 250-295 GPa. These structures are stabilized with respect to strongly bonded molecular phases at room temperature by the presence of lower frequency vibrational modes arising from the graphene-like sheets. Our results for the mixed structures are consistent with the experimental Raman data [M. I. Eremets and I. A. Troyan, Nat. Mater.1476-112210.1038/nmat3175 10, 927 (2011) and R. T. Howie , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.108.125501 108, 125501 (2012)]. We find that mixed phases are reasonable structural models for phase IV of hydrogen.

  9. Density-functional study of plutonium monoxide monohydride

    Science.gov (United States)

    Qiu, Ruizhi; Lu, Haiyan; Ao, Bingyun; Tang, Tao; Chen, Piheng

    2017-03-01

    The structural, electronic, mechanical, optical, thermodynamic properties of plutonium monoxide monohydride (PuOH) are studied by density-functional calculations within the framework of LDA/GGA and LDA/GGA+U. From the total energy calculation, the lowest-energy crystal structure of PuOH is predicted to have space group F 4 bar 3 m (No. 216). Within the LDA+U framework, the calculated lattice parameter of F 4 bar 3 m -PuOH is in good agreement with the experimental value and the corresponding ground state is predicted to be an antiferromagnetic charge-transfer insulator. Furthermore, we investigate the bonding character of PuOH by analyzing the electron structure and find that there are a stronger Pu-O bond and a weaker Pu-H bond. The mechanical properties including the elastic constants, elastic moduli and Debye's temperature, and the optical properties including the reflectivity and absorption coefficient are also calculated. We then compute the phonon spectrum which verified the dynamical stability of F 4 bar 3 m -PuOH. Some thermodynamic quantities such as the specific heat are evaluated. Finally we calculate the formation energy of PuOH, and the reaction energies for the oxidation of PuOH and PuOH-coated Pu, which are in reasonable agreement with the experimental values.

  10. Ecological interaction and phylogeny, studying functionality on composed networks

    Science.gov (United States)

    Cruz, Claudia P. T.; Fonseca, Carlos Roberto; Corso, Gilberto

    2012-02-01

    We study a class of composed networks that are formed by two tree networks, TP and TA, whose end points touch each other through a bipartite network BPA. We explore this network using a functional approach. We are interested in how much the topology, or the structure, of TX (X=A or P) determines the links of BPA. This composed structure is a useful model in evolutionary biology, where TP and TA are the phylogenetic trees of plants and animals that interact in an ecological community. We make use of ecological networks of dispersion of fruits, which are formed by frugivorous animals and plants with fruits; the animals, usually birds, eat fruits and disperse their seeds. We analyse how the phylogeny of TX determines or is correlated with BPA using a Monte Carlo approach. We use the phylogenetic distance among elements that interact with a given species to construct an index κ that quantifies the influence of TX over BPA. The algorithm is based on the assumption that interaction matrices that follows a phylogeny of TX have a total phylogenetic distance smaller than the average distance of an ensemble of Monte Carlo realisations. We find that the effect of phylogeny of animal species is more pronounced in the ecological matrix than plant phylogeny.

  11. Density functional studies of methanol decomposition on subnanometer Pd clusters.

    Energy Technology Data Exchange (ETDEWEB)

    Mehmood, F.; Greeley, J.; Curtiss, L. A.

    2009-12-31

    A density functional theory study of the decomposition of methanol on subnanometer palladium clusters (primarily Pd{sub 4}) is presented. Methanol dehydrogenation through C-H bond breaking to form hydroxymethyl (CH{sub 2}OH) as the initial step, followed by steps involving formation of hydroxymethylene (CHOH), formyl (CHO), and carbon monoxide (CO), is found to be the most favorable reaction pathway. A competing dehydrogenation pathway with O-H bond breaking as the first step, followed by formation of methoxy (CH{sub 3}O) and formaldehyde (CH{sub 2}O), is slightly less favorable. In contrast, pathways involving C-O bond cleavage are much less energetically favorable, and no feasible pathways involving C-O bond formation to yield dimethyl ether (CH{sub 3}OCH{sub 3}) are found. Comparisons of the results are made with methanol decomposition products adsorbed on more extended Pd surfaces; all reaction intermediates are found to bind slightly more strongly to the clusters than to the surfaces.

  12. The Neural Basis of Typewriting: A Functional MRI Study.

    Directory of Open Access Journals (Sweden)

    Yuichi Higashiyama

    Full Text Available To investigate the neural substrate of typewriting Japanese words and to detect the difference between the neural substrate of typewriting and handwriting, we conducted a functional magnetic resonance imaging (fMRI study in 16 healthy volunteers. All subjects were skillful touch typists and performed five tasks: a typing task, a writing task, a reading task, and two control tasks. Three brain regions were activated during both the typing and the writing tasks: the left superior parietal lobule, the left supramarginal gyrus, and the left premotor cortex close to Exner's area. Although typing and writing involved common brain regions, direct comparison between the typing and the writing task revealed greater left posteromedial intraparietal cortex activation in the typing task. In addition, activity in the left premotor cortex was more rostral in the typing task than in the writing task. These findings suggest that, although the brain circuits involved in Japanese typewriting are almost the same as those involved in handwriting, there are brain regions that are specific for typewriting.

  13. Density functional theory study of BnC clusters.

    Science.gov (United States)

    Liu, Chunhui; Han, Peilin; Tang, Mingsheng

    2011-05-15

    B(n)C clusters (n = 3-10) were studied at the density functional theory (DFT) (B3LYP)/6-311G** level of theory. The calculations predicted that the most stable configurations of the B(n) C clusters are the (n + 1)-membered cyclic structures. For boron-carbon clusters, the configurations containing greater numbers of three-membered boron rings are more favorable, except for the B(7)C and B(9)C clusters. Through molecular orbital analysis of these B(n)C clusters, we have concluded that π-electron delocalization plays a crucial role in the stability of n + 1-membered cyclic structures. In this paper, the relative stability of each cluster is discussed based on their single atomic-binding energies. The capability of clusters to obtain or lose an electron was also discussed, based on their vertical electron detachment energies (VDEs), adiabatic electron detachment energies (ADEs), vertical electron affinities (VEAs) and adiabatic electron affinities (AEAs). Copyright © 2011 John Wiley & Sons, Ltd.

  14. Comparative study on spreading function for directional wave spectra

    Digital Repository Service at National Institute of Oceanography (India)

    Bhat, S.S.; Anand, N.M.; Nayak, B.U.

    -dimensional wave energy S(f) and the directional spreading function D(f, theta). This paper reviews various spreading functions proposed in the past for estimating the directional wave energy and presents their application to the Indian wave condition. It is found...

  15. When Learning and Remembering Compete: A Functional MRI Study

    NARCIS (Netherlands)

    Huijbers, W.; Pennartz, C.M.A.; Cabeza, R.; Daselaar, S.M.

    2009-01-01

    Recent functional neuroimaging evidence suggests a bottleneck between learning new information and remembering old information. In two behavioral experiments and one functional MRI (fMRI) experiment, we tested the hypothesis that learning and remembering compete when both processes happen within a b

  16. Cerebral vasoreactivity and functional response in stroke: a study with functional MR

    National Research Council Canada - National Science Library

    Piñeiro, R; Matthews, P M

    2001-01-01

    .... To compare the temporal behaviour of the BOLD signal and the distribution of activation between a group of patients with no functional sequelae following a stroke and a control group, by using fMR at 3T...

  17. Informing saccharide structural NMR studies with density functional theory calculations.

    Science.gov (United States)

    Klepach, Thomas; Zhao, Hongqiu; Hu, Xiaosong; Zhang, Wenhui; Stenutz, Roland; Hadad, Matthew J; Carmichael, Ian; Serianni, Anthony S

    2015-01-01

    Density functional theory (DFT) is a powerful computational tool to enable structural interpretations of NMR spin-spin coupling constants ( J-couplings) in saccharides, including the abundant (1)H-(1)H ( JHH), (13)C-(1)H ( JCH), and (13)C-(13)C ( JCC) values that exist for coupling pathways comprised of 1-4 bonds. The multiple hydroxyl groups in saccharides, with their attendant lone-pair orbitals, exert significant effects on J-couplings that can be difficult to decipher and quantify without input from theory. Oxygen substituent effects are configurational and conformational in origin (e.g., axial/equatorial orientation of an OH group in an aldopyranosyl ring; C-O bond conformation involving an exocyclic OH group). DFT studies shed light on these effects, and if conducted properly, yield quantitative relationships between a specific J-coupling and one or more conformational elements in the target molecule. These relationships assist studies of saccharide structure and conformation in solution, which are often challenged by the presence of conformational averaging. Redundant J-couplings, defined as an ensemble of J-couplings sensitive to the same conformational element, are particularly helpful when the element is flexible in solution (i.e., samples multiple conformational states on the NMR time scale), provided that algorithms are available to convert redundant J-values into meaningful conformational models. If the latter conversion is achievable, the data can serve as a means of testing, validating, and refining theoretical methods like molecular dynamics (MD) simulations, which are currently relied upon heavily to assign conformational models of saccharides in solution despite a paucity of experimental data needed to independently validate the method.

  18. Systemic catechol-O-methyl transferase inhibition enables the D1 agonist radiotracer R-[11C]SKF 82957

    DEFF Research Database (Denmark)

    Palner, Mikael; McCormick, Patrick; Parkes, Jun

    2010-01-01

    R-[(11)C]-SKF 82957 is a high-affinity and potent dopamine D(1) receptor agonist radioligand, which gives rise to a brain-penetrant lipophilic metabolite. In this study, we demonstrate that systemic administration of catechol-O-methyl transferase (COMT) inhibitors blocks this metabolic pathway, f...

  19. Assessing function in patients undergoing joint replacement: a study protocol for a cohort study

    Directory of Open Access Journals (Sweden)

    Wylde Vikki

    2012-11-01

    Full Text Available Abstract Background Joint replacement is an effective intervention for people with advanced arthritis, although there is an important minority of patients who do not improve post-operatively. There is a need for robust evidence on outcomes after surgery, but there are a number of measures that assess function after joint replacement, many of which lack any clear theoretical basis. The World Health Organisation has introduced the International Classification of Functioning, Disability and Health (ICF, which divides function into three separate domains: Impairment, activity limitations and participation restrictions. The aim of this study is to compare the properties and responsiveness of a selection of commonly used outcome tools that assess function, examine how well they relate to the ICF concepts, and to explore the changes in the measures over time. Methods/design Two hundred and sixty three patients listed for lower limb joint replacement at an elective orthopaedic centre have been recruited into this study. Participants attend the hospital for a research appointment prior to surgery and then at 3-months and 1-year after surgery. At each assessment time, function is assessed using a range of measures. Self-report function is assessed using the WOMAC, Aberdeen Impairment, Activity Limitation and Participation Restriction Measure, SF-12 and Measure Yourself Medical Outcome Profile 2. Clinician-administered measures of function include the American Knee Society Score for knee patients and the Harris Hip Score for hip patients. Performance tests include the timed 20-metre walk, timed get up and go, sit-to-stand-to-sit, step tests and single stance balance test. During the performance tests, participants wear an inertial sensor and data from motion analysis are collected. Statistical analysis will include exploring the relationship between measures describing the same ICF concepts, assessing responsiveness, and studying changes in measures over

  20. Targeting somatostatin receptors in gastro entero pancreatic neuroendocrine tumours (G.E.P.N.E.T.): Which radiotracers for which tumours?;Ciblage des recepteurs de la somatostatine dans les tumeurs neuroendocrines gastroenteropancreatiques (TNE-GEP): quels radiotraceurs pour quelles tumeurs?

    Energy Technology Data Exchange (ETDEWEB)

    Cuny, T.; Saveanu, A.; Barlier, A. [CRN2M, UMR 6231, CNRS, laboratoire de neurobiologie et neurophysiologie de Marseille, faculte de medecine, 13 - Marseille (France); Saveanu, A.; Barlier, A. [Hotal de la Conception Assistance publique-hopitaux de Marseille, Laboratoire de biochimie, biologie moleculaire, 13 - Marseille (France); Taieb, D. [Hopital de la Timone, Assistance publique des hopitaux de Marseille, Service de medecine nucleaire, 13 - Marseille (France)

    2010-05-15

    Topographic and functional imaging hold a key position in endocrine oncology. In vivo somatostatin receptor scintigraphy using Indium-111 labeled DTPA-octreotide, a tracer with preferential affinity for the somatostatin receptor subtype 2 (sst2), is the gold-standard for initial diagnosis of gastro entero pancreatic neuroendocrine tumours (G.E.P.N.E.T.). Due to the detection limits of scintigraphy, other metabolic imaging modalities are required. Positron emission topography (PET) offers whole body scanning, facilitates tumour localization, and assesses the metastasis statement of the tumour. {sup 18}F-F.D.G. is the most frequent radiotracer used in clinical practice because of its availability, but its interest is demonstrated only in undifferentiated G.E.P.N.E.T.. More recently, {sup 18}F-DOPA PET showed a high sensitivity in particular in carcinoid tumours detection. PET using different {sup 68}Ga-labeled-somatostatin analogs with high affinity for sst2 displayed better results than somatostatin receptors scintigraphy (S.R.S.) in G.E.P.N.E.T. primary tumour and metastasis detection, especially when fusion with computerized tomography images was performed. Using similar metabolic targets, peptide receptor radionuclide therapy (P.R.R.T.) with {sup 177}Lu-octreotate and {sup 90}Y-DOTA-TOC, is indicated in disseminated G.E.P.N.E.T. forms with an efficiency of 30 % and a minor toxicity. (authors)

  1. Functional study of mammalian Neph proteins in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Martin Helmstädter

    Full Text Available Neph molecules are highly conserved immunoglobulin superfamily proteins (IgSF which are essential for multiple morphogenetic processes, including glomerular development in mammals and neuronal as well as nephrocyte development in D. melanogaster. While D. melanogaster expresses two Neph-like proteins (Kirre and IrreC/Rst, three Neph proteins (Neph1-3 are expressed in the mammalian system. However, although these molecules are highly abundant, their molecular functions are still poorly understood. Here we report on a fly system in which we overexpress and replace endogenous Neph homologs with mammalian Neph1-3 proteins to identify functional Neph protein networks required for neuronal and nephrocyte development. Misexpression of Neph1, but neither Neph2 nor Neph3, phenocopies the overexpression of endogenous Neph molecules suggesting a functional diversity of mammalian Neph family proteins. Moreover, structure-function analysis identified a conserved and specific Neph1 protein motif that appears to be required for the functional replacement of Kirre. Hereby, we establish D. melanogaster as a genetic system to specifically model molecular Neph1 functions in vivo and identify a conserved amino acid motif linking Neph1 to Drosophila Kirre function.

  2. Absolute and Convective Ion Beam Instability Studied through Green's Function

    DEFF Research Database (Denmark)

    Jensen, Vagn Orla; Michelsen, Poul; Hsuan, H. C. S.

    1974-01-01

    A Vlasov plasma with a double‐humped, unstable ion velocity distribution function is considered. A δ function in space is assumed as the initial perturbation and the plasma response to this perturbation is calculated, i.e., the Green's function for the problem is found. The response can be divide...... into two parts: a self‐similar, damped part of the form t−1h(x/t), and an unstable, exponentially growing part. The conditions for absolute and convective growth of the latter are discussed....

  3. Radioiodination and biological evaluation of levalbuterol as a new selective radiotracer. A β{sub 2}-adrenoceptor agonist

    Energy Technology Data Exchange (ETDEWEB)

    Sanad, Mahmoud Hamdi; Abelrahman, Mohamed Abdelmotelb; Marzook, Fawzy Mohamed Abdelmaged [Atomic Energy Authority, Cairo (Egypt). Radioisotopes Production and Radioactive Sources Div.

    2016-08-01

    Levalbuterol was successfully radiolabeled with iodine using chloramine-T as an oxidizing agent via an electrophilic substitution reaction. The reaction parameters that affecting the labeling yield such as levalbuterol concentration, chloramine-T concentration, pH of the reaction medium and reaction time were studied in details. The radiochemical yield was 97.5 ± 0.5% and the radioiodinated compound was separated by HPLC. In vitro studies showed that the iodinated levalbuterol was stable for up to 24 h. The biodistribution in experimental animals showed that the lung uptake was 68.18 ± 0.17% at 5 min post injection which decreased with time until reached to 18.7 ± 0.12% at 2 h which was higher than other recent developed radiopharmaceuticals for lung imaging. The clearance pathways from the mice appear to proceed via both hepatobiliary and renal pathways. Predosing the mice with cold levalbuterol reduced the lung uptake to 20 ± 1.3% and further confirms the high specificity and selectivity of {sup 125}I-levalbuterol for the lung.

  4. Communicative functioning in individuals with Angelman syndrome: a comparative study

    NARCIS (Netherlands)

    Didden, H.C.M.; Korzilius, H.P.L.M.; Duker, P.C.C.; Curfs, L.M.G

    2004-01-01

    PURPOSE: To assess expressive communication in individuals with Angelman syndrome. METHOD: Communicative functioning of individuals with Angelman syndrome (AS) (n=109) was compared with individuals with mixed etiologies (n=117) using the Verbal Behaviour Assessment Scale (VerBAS). RESULTS:

  5. Beta 2-adrenergic receptors on eosinophils. Binding and functional studies

    Energy Technology Data Exchange (ETDEWEB)

    Yukawa, T.; Ukena, D.; Kroegel, C.; Chanez, P.; Dent, G.; Chung, K.F.; Barnes, P.J. (National Heart and Lung Institute, Brompton Hospital, London (England))

    1990-06-01

    We have studied the binding characteristics and functional effects of beta-adrenoceptors on human and guinea pig eosinophils. We determined the binding of the beta-antagonist radioligand (125I)pindolol (IPIN) to intact eosinophils obtained from the peritoneal cavity of guinea pigs and from blood of patients with eosinophilia. Specific binding was saturable, and Scatchard analysis showed a single binding site with a dissociation constant (Kd) of 24.6 pM and maximal number of binding sites (Bmax) of 7,166 per cell. ICI 118,551, a beta 2-selective antagonist, inhibited IPIN binding with a Ki value of 0.28 nM and was approximately 5,000-fold more effective than the beta 1-selective antagonist, atenolol. Isoproterenol increased cAMP levels about 5.5-fold above basal levels (EC50 = 25 microM); albuterol, a beta 2-agonist, behaved as a partial agonist with a maximal stimulation of 80%. Binding to human eosinophils gave similar results with a Kd of 25.3 pM and a Bmax corresponding to 4,333 sites per cell. Incubation of both human and guinea pig eosinophils with opsonized zymosan (2 mg/ml) or with phorbol myristate acetate (PMA) (10(-8) and 10(-6) M) resulted in superoxide anion generation and the release of eosinophil peroxidase; albuterol (10(-7) to 10(-5) M) had no inhibitory effect on the release of these products. Thus, eosinophils from patients with eosinophilia and from the peritoneal cavity of guinea pigs possess beta-receptors of the beta 2-subtype that are coupled to adenylate cyclase; however, these receptors do not modulate oxidative metabolism or degranulation. The possible therapeutic consequences of these observations to asthma are discussed.

  6. EMG study for perioral facial muscles function during mastication.

    Science.gov (United States)

    Hanawa, S; Tsuboi, A; Watanabe, M; Sasaki, K

    2008-03-01

    This study aimed to clarify the temporal and quantitative modulation in the orbicularis oris (OO) and buccinator (BUC) muscle activities during mastication. Ten healthy males (26.9 +/- 1.0 years) participated. Electromyograms (EMGs) of the facial muscles were recorded with fine wire electrodes when chewing the chewing gum (one to four sticks) and peanuts (one to five pieces). Surface EMGs of the masseter (MAS) and digastric muscles were recorded simultaneously. EMGs of the OO and BUC showed rhythmic single-peaked bursts corresponding to the jaw-opening phase of chewing cycles. The total cycle lengths were constant regardless of the food amount. Integrated EMGs of the OO changed significantly when the amount of both foods changed (anova: P < 0.05). Those of the BUC changed significantly with the amount of gum changed (P < 0.05), but did not change with the amount of peanuts changed. The burst duration of OO changed significantly when the amount of gum changed during ipsilateral chewing (P < 0.05). When the amount of peanuts changed during ipsilateral chewing, the onset of OO and the peak of BUC based on the onset of MAS activity changed significantly (P < 0.05). However, the onset, peak and offset of the OO and BUC based on the offset of MAS did not change regardless of the amounts chewed. The changes of the OO and BUC activities may derive from chewing-generated sensory inputs in accordance with the physical property of food in part, which would relate to the function of these muscles during mastication.

  7. Density functional theory study of neutral and oxidized thiophene oligomers

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Yafei; Wei, Chengwei [School of Physics Science and Technology and Jiangsu Key Laboratory for NSLSCS, Nanjing Normal University, Nanjing 210023 (China); Blaisten-Barojas, Estela, E-mail: blaisten@gmu.edu [Computational Materials Science Center and School of Physics, Astronomy and Computational Sciences, George Mason University, Fairfax, Virginia 22030 (United States)

    2013-11-14

    The effect of oxidation on the energetics and structure of thiophene (Th) oligomers is studied with density functional theory at the B3PW91/6-311++G(d,p) level. Neutral n-Th oligomers (2 < n < 13) are gently curved planar chains. Ionization potential and electron affinity results show that n-Th oligomers are easier to be oxidized as their chain length increases. Oxidation states +2, +4, +6, and +8 are energetically stable in 12-Th. Upon oxidation the conjugated backbone of 12-Th switches from extended benzenoid phase to quinoid phase localized on groups of monomers regularly spaced along the chain. Oxidized states +2, +4, +6, and +8 of 12-Th display two +1e localized at the ends of their chains only because of the finite size of the chains. In 12-Th this end-effect extends over the two terminal monomers forming a positive-negative charge duet. This peculiar charge localization makes n-Th oligomers different from other conducting polymers with similar structure, such as polypyrrole. The spectrum of single-electron molecular states of oxidized 12-Th displays two localized single-electron states in the HOMO-LUMO energy gap per +2 oxidation state. Oligothiophene 12-Th doped with F atoms at 1:2 concentration presents a charge transfer of 3.4 e from oligomer to dopants that increases to 4.8 e in the presence of solvent. The charge distribution in these F-doped oligomers is similar to the +4 oxidation state of 12-Th. It is predicted that dopants produce an enhanced charge transfer localized in the proximity of their locations enhancing the formation of bipolarons in the central part of the oligomer chain.

  8. Brain Functional Connectivity in MS: An EEG-NIRS Study

    Science.gov (United States)

    2015-10-01

    oxygen- based ( near -infrared spectroscopy (NIRS), functional MRI (fMRI)) signals, and to use the results to help optimize BOLD fMRI analyses of brain...2. Keywords BOLD – blood oxygen level dependent EEG – electroencephalography NIRS – near -infrared spectroscopy fMRI – functional MRI MS...INTRODUCTION TO ELECTROENCEPHALOGRAPHY AND NEAR -INFRARED SPECTROSCOPY NEUROIMAGING MEASUREMENT AND ANALYSIS P.40LO GlACO~lETTT 1. COURSE O VERVIEW T he

  9. Radioiodinated famotidine as a new highly selective radiotracer for peptic ulcer disorder detection, diagnostic nuclear imaging and biodistribution

    Energy Technology Data Exchange (ETDEWEB)

    Sanad, M.H.; Marzook, F.A. [Atomic Energy Authority, Cairo (Egypt). Radioisotopes Production and Radioactive Source Div.; Salama, Dina H. [Atomic Energy Authority, Cairo (Egypt). National Center for Radiation Research and Technology

    2017-08-01

    Famotidine was labeled with iodine-125 to obtain {sup 125}I-famotidine ({sup 125}I-fam) as an agent for ulcer imaging. The radiochemical yield of {sup 125}I-famotidine reached approximately 98.5 ± 0.23% at optimum conditions of pH, oxidizing agent, reaction time and the amount of substrate. {sup 125}I-fam was stable for 48 h. Different chromatographic techniques were used to determine the radiochemical yield and purity. Intravenous biodistribution studies of {sup 125}I-fam revealed high concentration in the stomach ulcer, reaching about 65.9 ± 0.28% of the total injected dose at 30 min post injection. This concentration of {sup 125}I-fam in stomach ulcer makes this agent promising for stomach ulcer imaging.

  10. Autonomic nervous system function in patients with functional abdominal pain. An experimental study

    DEFF Research Database (Denmark)

    Jørgensen, L S; Christiansen, P; Raundahl, U

    1993-01-01

    disturbed in 22 patients with functional abdominal pain (functional group) as compared with 14 healthy controls (healthy group) and 26 patients with organic abdominal pain (organic group) due to duodenal ulcer (DU), gallstones, or urinary tract calculi. Plasma adrenocorticotrophic hormone (ACTH) and serum...... cortisol measurements were included, to assess the pituitary-adrenocortical axis. Heart rate, systolic blood pressure, and plasma adrenaline increased significantly in all groups in response to a stress test (mental arithmetic). Plasma noradrenaline increased in the DU patients only, and plasma ACTH...

  11. Activated and deactivated functional brain areas in the Deqi state: A functional MRI study.

    Science.gov (United States)

    Huang, Yong; Zeng, Tongjun; Zhang, Guifeng; Li, Ganlong; Lu, Na; Lai, Xinsheng; Lu, Yangjia; Chen, Jiarong

    2012-10-25

    We compared the activities of functional regions of the brain in the Deqi versus non-Deqi state, as reported by physicians and subjects during acupuncture. Twelve healthy volunteers received sham and true needling at the Waiguan (TE5) acupoint. Real-time cerebral functional MRI showed that compared with non-sensation after sham needling, true needling activated Brodmann areas 3, 6, 8, 9, 10, 11, 13, 20, 21, 37, 39, 40, 43, and 47, the head of the caudate nucleus, the parahippocampal gyrus, thalamus and red nucleus. True needling also deactivated Brodmann areas 1, 2, 3, 4, 5, 6, 7, 9, 10, 18, 24, 31, 40 and 46.

  12. Density functional theory study of the oligomerization of carboxylic acids.

    Science.gov (United States)

    Di Tommaso, Devis; Watson, Ken L

    2014-11-20

    We present a density functional theory [M06-2X/6-31+G(d,p)] study of the structures and free energies of formation of oligomers of four carboxylic acids (formic acid, acetic acid, tetrolic acid, and benzoic acid) in water, chloroform, and carbon tetrachloride. Solvation effects were treated using the SMD continuum solvation model. The low-lying energy structures of molecular complexes were located by adopting an efficient search procedure to probe the potential energy surfaces of the oligomers of carboxylic acids (CA)n (n = 2-6). The free energies of the isomers of (CA)n in solution were determined as the sum of the electronic energy, vibrational-rotational-translational gas-phase contribution, and solvation free energy. The assessment of the computational protocol adopted in this study with respect to the dimerization of acetic acid, (AA)2, and formic acid, (FA)2, located new isomers of (AA)2 and (FA)2 and gave dimerization constants in good agreement with the experimental values. The calculation of the self-association of acetic acid, tetrolic acid, and benzoic acid shows the following: (i) Classic carboxylic dimers are the most stable isomer of (CA)2 in both the gas phase and solution. (ii) Trimers of carboxylic acid are stable in apolar aprotic solvents. (iii) Molecular clusters consisting of two interacting classic carboxylic dimers (CA)4,(D+D) are the most stable type of tetramers, but their formation from the self-association of classic carboxylic dimers is highly unfavorable. (iv) For acetic acid and tetrolic acid the reactions (CA)2 + 2CA → (CA)4,(D+D) and (CA)3 + CA → (CA)4,(D+D) are exoergonic, but these aggregation pathways go through unstable clusters that could hinder the formation of tetrameric species. (v) For tetrolic acid the prenucleation species that are more likely to form in solution are dimeric and trimeric structures that have encoded structural motifs resembling the α and β solid forms of tetrolic acid. (vi) Stable tetramers of

  13. Theranostic Approach for Metastatic Pigmented Melanoma Using ICF15002, a Multimodal Radiotracer for Both PET Imaging and Targeted Radionuclide Therapy

    Directory of Open Access Journals (Sweden)

    Latifa Rbah-Vidal

    2017-01-01

    Full Text Available PURPOSE: This work reports, in melanoma models, the theranostic potential of ICF15002 as a single fluorinated and iodinated melanin-targeting compound. METHODS: Studies were conducted in the murine syngeneic B16BL6 model and in the A375 and SK-MEL-3 human xenografts. ICF15002 was radiolabeled with fluorine-18 for positron emission tomography (PET imaging and biodistribution, with iodine-125 for metabolism study, and iodine-131 for targeted radionuclide therapy (TRT. TRT efficacy was assessed by tumor volume measurement, with mechanistics and dosimetry parameters being determined in the B16BL6 model. Intracellular localization of ICF15002 was characterized by secondary ion mass spectrometry (SIMS. RESULTS: PET imaging with [18F]ICF15002 evidenced tumoral uptake of 14.33 ± 2.11%ID/g and 4.87 ± 0.93%ID/g in pigmented B16BL6 and SK-MEL-3 models, respectively, at 1 hour post inoculation. No accumulation was observed in the unpigmented A375 melanoma. SIMS demonstrated colocalization of ICF15002 signal with melanin polymers in melanosomes of the B16BL6 tumors. TRT with two doses of 20 MBq [131I]ICF15002 delivered an absorbed dose of 102.3 Gy to B16BL6 tumors, leading to a significant tumor growth inhibition [doubling time (DT of 2.9 ± 0.5 days in treated vs 1.8 ± 0.3 in controls] and a prolonged median survival (27 days vs 21 in controls. P53S15 phosphorylation and P21 induction were associated with a G2/M blockage, suggesting mitotic catastrophe. In the human SK-MEL-3 model, three doses of 25 MBq led also to a DT increase (26.5 ± 7.8 days vs 11.0 ± 3.8 in controls and improved median survival (111 days vs 74 in controls. CONCLUSION: Results demonstrate that ICF15002 fulfills suitable properties for bimodal imaging/TRT management of patients with pigmented melanoma.

  14. Evaluation of technetium-99m/rhenium labelled nucleoside analogues as potential radiotracers in oncology[Dissertation 17173

    Energy Technology Data Exchange (ETDEWEB)

    Desbouis, D

    2007-07-01

    substrate activity with respect to recombinant hTKl. The phosphorylation rates of neutral and negative complexes were found to be similar, ranging between 15-16% with respect to thymidine (100%) whereas the phosphorylation rate of the positive complex was found to be significantly lower with 9.5 {+-} 1.8%. Neutral compounds with three, five and ten carbons spacers were all found to be more potent than the neutral complex with two carbons spacers. The best rate was observed for the compound with the five carbons spacer with 21.5 {+-} 1.1%. Molecular dynamics (MD) calculations were performed with a homology model based on hTKl and Clostridium acetobutylicum thymidine kinase. MD have shown that the contact between Glu98, the amino acid responsible for deprotonation, and H5' is conserved for all spacer lengths. The different activity can be explained by the fact that the tricarbonyl moiety docks to different part of the protein in function of the spacer length. Since it was likely that these complexes would enter the cells via passive diffusion, they were characterized by the physicochemical parameter log P to give insight into their lipophilicity. The three complexes with the short spacer displayed negative log P values ranging from -1.67 {+-} 0.02 (positively charged complex) to -0.42 {+-} 0.01 (neutral complex). It was then reasoned to increase the spacer length of the neutral complex to reach more favourable physicochemical properties for passive diffusion. Interestingly, the log P value of the complex with the ten carbon spacer was found to be 1.1 {+-} 0.1, which indicates a gain in lipophilicity. Only this complex was internalised in two cancer cell lines in vitro (4.8 {+-} 0.5 and 3.3 {+-} 0.2%ID/(mg/mL)). Finally, this technetium-99m complex was tested in vivo in nude mice bearing HT-29 xenografts. The results suggest that the compound was rapidly metabolized and excreted via the hepatobiliary route. Consequently, the tumour uptake was low, which precludes the use

  15. Engineering the work function of armchair graphene nanoribbons using strain and functional species: a first principles study.

    Science.gov (United States)

    Peng, Xihong; Tang, Fu; Copple, Andrew

    2012-02-22

    First principles density functional theory calculations were performed to study the effects of strain, edge passivation, and surface functional species on the structural and electronic properties of armchair graphene nanoribbons (AGNRs), with a particular focus on the work function. The work function was found to increase with uniaxial tensile strain and decrease with compression. The variation of the work function under strain is primarily due to the shift of the Fermi energy with strain. In addition, the relationship between the work function variation and the core level shift with strain is discussed. Distinct trends of the core level shift under tensile and compressive strain were discovered. For AGNRs with the edge carbon atoms passivated by oxygen, the work function is higher than for nanoribbons with the edge passivated by hydrogen under a moderate strain. The difference between the work functions in these two edge passivations is enlarged (reduced) under a sufficient tensile (compressive) strain. This has been correlated to a direct-indirect bandgap transition for tensile strains of about 4% and to a structural transformation for large compressive strains at about - 12%. Furthermore, the effect of the surface species decoration, such as H, F, or OH with different covering density, was investigated. It was found that the work function varies with the type and coverage of surface functional species. Decoration with F and OH increases the work function while H decreases it. The surface functional species were decorated on either one side or both sides of AGNRs. The difference in the work functions between one-sided and two-sided decorations was found to be relatively small, which may suggest an introduced surface dipole plays a minor role.

  16. The western Mediterranean basin as an aged aerosols reservoir. Insights from an old-fashioned but efficient radiotracer

    Science.gov (United States)

    Brattich, E.; Hernández-Ceballos, M. A.; Orza, J. A. G.; Bolívar, J. P.; Tositti, L.

    2016-09-01

    The long-term contemporary 210Pb time series acquired during the period 2004-2011 at two distant sites of different altitude in the Mediterranean basin, El Arenosillo (40 m a.s.l. in southwestern Spain) and Mt. Cimone (2165 m a.s.l. in northern Italy), are analyzed and compared. Besides being considered a tracer of continental air masses, 210Pb radionuclide is also a proxy of fine stable aerosol. For this reason, the measurements of PM10 mass concentrations collected at the same time and the corresponding 210Pb/PM10 ratio at the two sites are considered to gain better insights into the origin and size of the particles. Three statistical trajectory methods are applied to identify and characterize the 210Pb source regions at the two sites. The three methods yield similar outcomes in the source identification, which strengthens the robustness of our results. In addition to the importance of the transport from areas of continental Europe, this study highlights the relevant role of the Mediterranean Sea as a major 210Pb reservoir layer associated to the aged air masses that accumulate in the western Mediterranean basin. The analysis of the sources points out the significant influence of northern Africa to 210Pb increases at both sites as well, even though the most intensive episodes are not of Saharan origin.

  17. Biokinetics of Hg and Pb accumulation in the encapsulated egg of the common cuttlefish Sepia officinalis: Radiotracer experiments

    Energy Technology Data Exchange (ETDEWEB)

    Lacoue-Labarthe, T., E-mail: tlacouel@gmail.com [Littoral, Environnement et Societes (LIENSs), UMR 6250, CNRS-Universite de La Rochelle, 2 rue Olympe de Gouges, F-17042 La Rochelle Cedex 01 (France); Warnau, M., E-mail: warnaumichel@yahoo.com [International Atomic Energy Agency - Marine Environment Laboratories, 4 Quai Antoine Ier, MC-98000 (Monaco); Metian, M. [Littoral, Environnement et Societes (LIENSs), UMR 6250, CNRS-Universite de La Rochelle, 2 rue Olympe de Gouges, F-17042 La Rochelle Cedex 01 (France); International Atomic Energy Agency - Marine Environment Laboratories, 4 Quai Antoine Ier, MC-98000 (Monaco); Oberhaensli, F. [International Atomic Energy Agency - Marine Environment Laboratories, 4 Quai Antoine Ier, MC-98000 (Monaco); Rouleau, C. [Institut Maurice-Lamontagne, 850 Route de la Mer, C.P. 1000, Mont-Joli, Quebec (Canada); Bustamante, P., E-mail: pbustama@univ-lr.fr [Littoral, Environnement et Societes (LIENSs), UMR 6250, CNRS-Universite de La Rochelle, 2 rue Olympe de Gouges, F-17042 La Rochelle Cedex 01 (France)

    2009-12-01

    Uptake and depuration kinetics of dissolved {sup 203}Hg and {sup 210}Pb were determined during the entire embryonic development of the eggs of the cuttlefish, Sepia officinalis (50 d at 17 {sup o}C). {sup 203}Hg and {sup 210}Pb were accumulated continuously by the eggs all along the development time reaching load/concentration ratio (LCR) of 467 {+-} 43 and 1301 {+-} 126 g, respectively. During the first month, most of the {sup 203}Hg and {sup 210}Pb remained associated with the eggshell indicating that the latter acted as an efficient shield against metal penetration. From this time onwards, {sup 203}Hg accumulated in the embryo, indicating that it passed through the eggshell, whereas {sup 210}Pb did not cross the chorion during the whole exposure time. It also demonstrated that translocation of Hg associated with the inner layers of the eggshell is a significant source of exposure for the embryo. This study highlighted that the maturing embryo could be subjected to the toxic effects of Hg in the coastal waters where the embryonic development is taking place.

  18. Fatty Acid Amide Hydrolase Binding in Brain of Cannabis Users: Imaging With the Novel Radiotracer [(11)C]CURB.

    Science.gov (United States)

    Boileau, Isabelle; Mansouri, Esmaeil; Williams, Belinda; Le Foll, Bernard; Rusjan, Pablo; Mizrahi, Romina; Tyndale, Rachel F; Huestis, Marilyn A; Payer, Doris E; Wilson, Alan A; Houle, Sylvain; Kish, Stephen J; Tong, Junchao

    2016-11-01

    One of the major mechanisms for terminating the actions of the endocannabinoid anandamide is hydrolysis by fatty acid amide hydrolase (FAAH), and inhibitors of the enzyme were suggested as potential treatment for human cannabis dependence. However, the status of brain FAAH in cannabis use disorder is unknown. Brain FAAH binding was measured with positron emission tomography and [(11)C]CURB in 22 healthy control subjects and ten chronic cannabis users during early abstinence. The FAAH genetic polymorphism (rs324420) and blood, urine, and hair levels of cannabinoids and metabolites were determined. In cannabis users, FAAH binding was significantly lower by 14%-20% across the brain regions examined than in matched control subjects (overall Cohen's d = 0.96). Lower binding was negatively correlated with cannabinoid concentrations in blood and urine and was associated with higher trait impulsiveness. Lower FAAH binding levels in the brain may be a consequence of chronic and recent cannabis exposure and could contribute to cannabis withdrawal. This effect should be considered in the development of novel treatment strategies for cannabis use disorder that target FAAH and endocannabinoids. Further studies are needed to examine possible changes in FAAH binding during prolonged cannabis abstinence and whether lower FAAH binding predates drug use. Copyright © 2016 Society of Biological Psychiatry. All rights reserved.

  19. Chronic antiepileptic drug use and functional network efficiency: A functional magnetic resonance imaging study.

    Science.gov (United States)

    van Veenendaal, Tamar M; IJff, Dominique M; Aldenkamp, Albert P; Lazeron, Richard H C; Hofman, Paul A M; de Louw, Anton J A; Backes, Walter H; Jansen, Jacobus F A

    2017-06-28

    To increase our insight in the neuronal mechanisms underlying cognitive side-effects of antiepileptic drug (AED) treatment. The relation between functional magnetic resonance-acquired brain network measures, AED use, and cognitive function was investigated. Three groups of patients with epilepsy with a different risk profile for developing cognitive side effects were included: A "low risk" category (lamotrigine or levetiracetam, n = 16), an "intermediate risk" category (carbamazepine, oxcarbazepine, phenytoin, or valproate, n = 34) and a "high risk" category (topiramate, n = 5). Brain connectivity was assessed using resting state functional magnetic resonance imaging and graph theoretical network analysis. The Computerized Visual Searching Task was used to measure central information processing speed, a common cognitive side effect of AED treatment. Central information processing speed was lower in patients taking AEDs from the intermediate and high risk categories, compared with patients from the low risk category. The effect of risk category on global efficiency was significant (P 0.2). Also no significant associations between information processing speed and global efficiency or the clustering coefficient (linear regression analysis, P > 0.15) were observed. Only the four patients taking topiramate show aberrant network measures, suggesting that alterations in functional brain network organization may be only subtle and measureable in patients with more severe cognitive side effects.

  20. Density functional studies of functionalized graphitic materials with late transition metals for oxygen reduction reactions

    DEFF Research Database (Denmark)

    Vallejo, Federico Calle; Martinez, Jose Ignacio; Rossmeisl, Jan

    2011-01-01

    ) at the cathode. In this contribution, on the basis of Density Functional Theory (DFT) calculations, we show that graphitic materials with active sites composed of 4 nitrogen atoms and transition metal atoms belonging to groups 7 to 9 in the periodic table are active towards ORR, and also towards Oxygen Evolution...

  1. Compensating for Executive Function Impairments after TBI: A Single Case Study of Functional Intervention.

    Science.gov (United States)

    Turkstra, Lyn S.; Flora, Tracy L.

    2002-01-01

    Compensatory strategies were designed to enable a client with traumatic brain injury to obtain professional employment. In a series of speech-language therapy sessions, compensatory strategies targeting impairments in executive function were developed, refined, and trained in mock-interview situations. Significant improvements were noted in…

  2. Posterior cingulated cortex functional connectivity in deficit schizophrenia: a resting state functional magnetic resonance imaging study

    Institute of Scientific and Technical Information of China (English)

    唐小伟

    2014-01-01

    Objective To explore the discrepancies of the network of resting brain functional connectivity related to posterior cingulated cortex(PCC)between deficit schizophrenia patients and normal control.Methods Thirty male patients of deficit schizophrenia,nondeficit schizophrenia and 30 healthy controls were enrolled,and the age,education level and sex were matched between three

  3. {sup 18}F-GE-180: a novel TSPO radiotracer compared to {sup 11}C-R-PK11195 in a preclinical model of stroke

    Energy Technology Data Exchange (ETDEWEB)

    Boutin, Herve; Gerhard, Alexander [University of Manchester, Faculty of Medical and Human Sciences, Manchester (United Kingdom); University of Manchester, Wolfson Molecular Imaging Centre, Manchester (United Kingdom); Murray, Katie [University of Manchester, Faculty of Life Sciences, Manchester (United Kingdom); Pradillo, Jesus [University of Manchester, Faculty of Life Sciences, Manchester (United Kingdom); Universidad Complutense/Politecnica de Madrid, Madrid (Spain); Maroy, Renaud [SHFJ - CEA Orsay, Orsay (France); Smigova, Alison [University of Manchester, Wolfson Molecular Imaging Centre, Manchester (United Kingdom); Jones, Paul A.; Trigg, William [GE Healthcare Ltd., Amersham (United Kingdom)

    2014-10-29

    Neuroinflammation plays a critical role in various neuropathological conditions, and hence there is renewed interest in the translocator protein (TSPO) as a biomarker of microglial activation and macrophage infiltration in the brain. This is reflected in the large amount of research conducted seeking to replace the prototypical PET radiotracer {sup 11}C-R-PK11195 with a TSPO ligand with higher performance. Here we report the in vivo preclinical investigation of the novel TSPO tracer {sup 18}F-GE-180 in a rat model of stroke. Focal cerebral ischaemia was induced in Wistar rats by 60-min occlusion of the middle cerebral artery (MCAO). Brain damage was assessed 24 h after MCAO by T2 MRI. Rats were scanned with {sup 11}C-R-PK11195 and {sup 18}F-GE-180 5 or 6 days after MCAO. Specificity of binding was confirmed by injection of unlabelled R-PK11195 or GE-180 20 min after injection of {sup 18}F-GE-180. In vivo data were confirmed by ex vivo immunohistochemistry for microglial (CD11b) and astrocytic biomarkers (GFAP). {sup 18}F-GE-180 uptake was 24 % higher in the core of the ischaemic lesion and 18 % lower in the contralateral healthy tissue than that of {sup 11}C-R-PK11195 uptake (1.5 ± 0.2-fold higher signal to noise ratio). We confirmed this finding using the simplified reference tissue model (BP{sub ND} = 3.5 ± 0.4 and 2.4 ± 0.5 for {sup 18}F-GE-180 and {sup 11}C-R-PK11195, respectively, with R{sub 1} = 1). Injection of unlabelled R-PK11195 or GE-180 20 min after injection of {sup 18}F-GE-180 significantly displaced {sup 18}F-GE-180 (69 ± 5 % and 63 ± 4 %, respectively). Specificity of the binding was also confirmed by in vitro autoradiography, and the location and presence of activated microglia and infiltrated macrophages were confirmed by immunohistochemistry. The in vivo binding characteristics of {sup 18}F-GE-180 demonstrate a better signal to noise ratio than {sup 11}C-R-PK11195 due to both a better signal in the lesion and lower nonspecific binding in

  4. Invasive and noninvasive methods for studying pulmonary function in mice

    Directory of Open Access Journals (Sweden)

    Braun Armin

    2007-09-01

    Full Text Available Abstract The widespread use of genetically altered mouse models of experimental asthma has stimulated the development of lung function techniques in vivo to characterize the functional results of genetic manipulations. Here, we describe various classical and recent methods of measuring airway responsiveness in vivo including both invasive methodologies in anesthetized, intubated mice (repetitive/non-repetitive assessment of pulmonary resistance (RL and dynamic compliance (Cdyn; measurement of low-frequency forced oscillations (LFOT and noninvasive technologies in conscious animals (head-out body plethysmography; barometric whole-body plethysmography. Outlined are the technical principles, validation and applications as well as the strengths and weaknesses of each methodology. Reviewed is the current set of invasive and noninvasive methods of measuring murine pulmonary function, with particular emphasis on practical considerations that should be considered when applying them for phenotyping in the laboratory mouse.

  5. Oxidative stress markers, cognitive functions, and psychosocial functioning in bipolar disorder: an empirical cross-sectional study

    Directory of Open Access Journals (Sweden)

    Ömer Aydemir

    2014-12-01

    Full Text Available Objective: This study aimed to evaluate the relationship between oxidative stress markers and cognitive functions and domains of psychosocial functioning in bipolar disorder. Methods: Oxidative stress markers, cognitive functions, and domains of psychosocial functioning were evaluated in 51 patients with bipolar disorder who were in remission. Correlation analyses between these parameters were calculated with data controlled for duration of illness and number of episodes. Results: There was no statistically significant correlation between oxidative stress markers and cognitive functions. In terms of psychosocial functioning, significant correlations were found between malondialdehyde and sense of stigmatization (r = -0.502; household activities and superoxide dismutase (r = 0.501; participation in social activities and nitric oxide (r = 0.414; hobbies and leisure time activities and total glutathione (r = -0.567, superoxide dismutase (r = 0.667, and neurotrophin 4 (r = 0.450; and taking initiative and self-sufficiency and superoxide dismutase (r = 0.597. There was no correlation between other domains of psychosocial functioning and oxidative stress markers. Conclusion: These results imply that oxidative stress markers do not appear to correlate clearly with cognitive impairment and reduced psychosocial functioning. However, there were some associations between selected oxidative markers and activity-oriented functional markers. This may represent a true negative association, or may be an artifact of oxidative stress being a state rather than a trait marker.

  6. Functional renormalization group study of fluctuation effects in fermionic superfluids

    Energy Technology Data Exchange (ETDEWEB)

    Eberlein, Andreas

    2013-03-22

    This thesis is concerned with ground state properties of two-dimensional fermionic superfluids. In such systems, fluctuation effects are particularly strong and lead for example to a renormalization of the order parameter and to infrared singularities. In the first part of this thesis, the fermionic two-particle vertex is analysed and the fermionic renormalization group is used to derive flow equations for a decomposition of the vertex in charge, magnetic and pairing channels. In the second part, the channel-decomposition scheme is applied to various model systems. In the superfluid state, the fermionic two-particle vertex develops rich and singular dependences on momentum and frequency. After simplifying its structure by exploiting symmetries, a parametrization of the vertex in terms of boson-exchange interactions in the particle-hole and particle-particle channels is formulated, which provides an efficient description of the singular momentum and frequency dependences. Based on this decomposition of the vertex, flow equations for the effective interactions are derived on one- and two-loop level, extending existing channel-decomposition schemes to (i) the description of symmetry breaking in the Cooper channel and (ii) the inclusion of those two-loop renormalization contributions to the vertex that are neglected in the Katanin scheme. In the second part, the superfluid ground state of various model systems is studied using the channel-decomposition scheme for the vertex and the flow equations. A reduced model with interactions in the pairing and forward scattering channels is solved exactly, yielding insights into the singularity structure of the vertex. For the attractive Hubbard model at weak coupling, the momentum and frequency dependence of the two-particle vertex and the frequency dependence of the self-energy are determined on one- and two-loop level. Results for the suppression of the superfluid gap by fluctuations are in good agreement with the literature

  7. Zinc surface complexes on birnessite: A density functional theory study

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Kideok D.; Refson, Keith; Sposito, Garrison

    2009-01-05

    Biogeochemical cycling of zinc is strongly influenced by sorption on birnessite minerals (layer-type MnO2), which are found in diverse terrestrial and aquatic environments. Zinc has been observed to form both tetrahedral (Zn{sup IV}) and octahedral (Zn{sup VI}) triple-corner-sharing surface complexes (TCS) at Mn(IV) vacancy sites in hexagonal birnessite. The octahedral complex is expected to be similar to that of Zn in the Mn oxide mineral, chalcophanite (ZnMn{sub 3}O{sub 7} {center_dot} 3H{sub 2}O), but the reason for the occurrence of the four-coordinate Zn surface species remains unclear. We address this issue computationally using spin-polarized Density Functional Theory (DFT) to examine the Zn{sub IV}-TCS and Zn{sup VI}-TCS species. Structural parameters obtained by DFT geometry optimization were in excellent agreement with available experimental data on Zn-birnessites. Total energy, magnetic moments, and electron-overlap populations obtained by DFT for isolated Zn{sup IV}-TCS revealed that this species is stable in birnessite without a need for Mn(III) substitution in the octahedral sheet and that it is more effective in reducing undersaturation of surface O at a Mn vacancy than is Zn{sub VI}-TCS. Comparison between geometry-optimized ZnMn{sub 3}O{sub 7} {center_dot} 3H{sub 2}O (chalcophanite) and the hypothetical monohydrate mineral, ZnMn{sub 3}O{sub 7} {center_dot} H{sub 2}O, which contains only tetrahedral Zn, showed that the hydration state of Zn significantly affects birnessite structural stability. Finally, our study also revealed that, relative to their positions in an ideal vacancy-free MnO{sub 2}, Mn nearest to Zn in a TCS surface complex move toward the vacancy by 0.08-0.11 {angstrom}, while surface O bordering the vacancy move away from it by 0.16-0.21 {angstrom}, in agreement with recent X-ray absorption spectroscopic analyses.

  8. Functional food consumption in Germany: A lifestyle segmentation study

    OpenAIRE

    Franz, Annabell; Nowak, Beate

    2010-01-01

    Due to increasing health consciousness among consumers, there is an ever‐growing demand for food and beverages with health‐improving components. Not only ‘light’ and low fat products are in demand, but increasingly so‐called well‐being products and food which can prevent certain diseases. The German market for functional food is still growing. But who are the German functional food consumers? In an online‐survey referring to the Food‐ Related Lifestyle by BRUNSØ and GRUNERT (1995) we tried to...

  9. DFT studies of CNT-functionalized uracil-acetate hybrids

    Science.gov (United States)

    Mirzaei, Mahmoud; Gulseren, Oguz

    2015-09-01

    Calculations based on density functional theory (DFT) have been performed to investigate the stabilities and properties of hybrid structures consisting of a molecular carbon nanotube (CNT) and uracil acetate (UA) counterparts. The investigated models have been relaxed to minimum energy structures and then various physical properties and nuclear magnetic resonance (NMR) properties have been evaluated. The results indicated the effects of functionalized CNT on the properties of hybrids through comparing the results of hybrids and individual structures. The oxygen atoms of uracil counterparts have been seen as the detection points of properties for the CNT-UA hybrids.

  10. The functions of laminins: lessons from in vivo studies

    DEFF Research Database (Denmark)

    Ryan, M C; Christiano, A M; Engvall, E

    1996-01-01

    diversity of the laminin family members makes highly specialized functions possible. While all laminins may share many functional properties, the individual chains are involved in interactions which cannot be substituted for by other laminins or by other basement membrane components. While this concept...... is how strongly the induced mouse mutations mimic human disease. With all the concerns with genetic background differences and species specific effects, manipulation of the laminin genes appears to be a particularly good first approach to identifying the causes of human disease. There is an abundant...

  11. Aberrant functional connectivity within the basal ganglia of patients with Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Michal Rolinski

    2015-01-01

    Full Text Available Resting state functional MRI (rs-fMRI has been previously shown to be a promising tool for the assessment of early Parkinson's disease (PD. In order to assess whether changes within the basal ganglia network (BGN are disease specific or relate to neurodegeneration generally, BGN connectivity was assessed in 32 patients with early PD, 19 healthy controls and 31 patients with Alzheimer's disease (AD. Voxel-wise comparisons demonstrated decreased connectivity within the basal ganglia of patients with PD, when compared to patients with AD and healthy controls. No significant changes within the BGN were seen in AD, when compared to healthy controls. Moreover, measures of functional connectivity extracted from regions within the basal ganglia were significantly lower in the PD group. Consistent with previous radiotracer studies, the greatest change when compared to the healthy control group was seen in the posterior putamen of PD subjects. When combined into a single component score, this method differentiated PD from AD and healthy control subjects, with a diagnostic accuracy of 81%. Rs-fMRI can be used to demonstrate the aberrant functional connectivity within the basal ganglia of patients with early PD. These changes are likely to be representative of patho-physiological basal ganglia dysfunction and are not associated with generalised neurodegeneration seen in AD. Further studies are necessary to ascertain whether this method is sensitive enough to detect basal ganglia dysfunction in prodromal PD, and its utility as a potential diagnostic biomarker for premotor and early motoric disease.

  12. Functional magnetic resonance imaging and immunohistochemical study of hypothalamic function following oral glucose ingestion in rats

    Institute of Scientific and Technical Information of China (English)

    CHEN Min; ZHAO Wei-feng; LI Sa-ying; WANG Zhi; ZHANG Yun-ting; LI Guo-zhen; ZHANG Tie-mei; LUO Sen-lin; ZHOU Cheng; WU Xiao-meng; ZHOU Ni-na; CAI Kui; YANG Zhen-han; WANG Wen-chao

    2007-01-01

    Background The hypothalamus plays a central role in the regulation of metabolism by sensing metabolic demands and releasing regulatory neurotransmitters. This study investigated the response of the hypothalamus to glucose ingestion in rats by blood oxygen level-dependent functional magnetic resonance imaging (BOLD-fMRI) and immunohistochemical techniques to determine the role of the hypothalamus in glycoregulation during disturbances in carbohydrate metabolism.Methods The signal intensity of the hypothalamus was monitored by fMRI for 60 minutes after oral glucose intake in 48 healthy rats (age 14 months), which included 24 normal weight rats (weighing (365±76.5) g) and 24 overweight rats (weighing (714±83.5) g). Then, 12 rats (6 normal, 6 overweight) underwent a repeat fMRI scan after consuming an equivalent amount of water without glucose on a separate day. The procedure for fMRI with water intake was the same as for glucose ingestion. fMRI data was processed using time cluster analysis and intensity averaging method. After fMRI,the expression of neuropeptide Y (NPY) and 5-hydroxytryptamine (5-HT) in the hypothalamus of all rats was determined by immunohistochemistry. Positive cells for NPY or 5-HT were counted.Results There was a transient, but significant, decrease in fMRI signal intensity in all rats (mean (3.12±0.78)%) in the hypothalamus within 19.5-25.5 minutes of oral glucose ingestion. In overweight rats, the decrease in signal intensity in response to the glucose ingestion was more markedly attenuated than that observed in normal weight rats ((2.2±1.5)%vs (4.2±0.7)% inhibition, t=2.12, P<0.05). There was no significant response in the hypothalamus after oral water ingestion. The percentage of NPY positive cells in obese rats were slightly lower than those in control group (21% vs 23%,t=0.71, P>0.05); but there was no significant difference between the two groups; the percentage of 5-HT positive cells in obese rats were significantly lower than

  13. Autonomic nervous system function in patients with functional abdominal pain. An experimental study

    DEFF Research Database (Denmark)

    Jørgensen, L S; Christiansen, P; Raundahl, U

    1993-01-01

    cortisol measurements were included, to assess the pituitary-adrenocortical axis. Heart rate, systolic blood pressure, and plasma adrenaline increased significantly in all groups in response to a stress test (mental arithmetic). Plasma noradrenaline increased in the DU patients only, and plasma ACTH...... response as indicated by a lesser stress-induced increment in heart rate, was seen in both patient groups (functional, 13 +/- 2 beats/min; organic, 10 +/- 2 beats/min) as compared with the healthy group (19 +/- 2 beats/min; P = 0.003).(ABSTRACT TRUNCATED AT 250 WORDS)...... and serum cortisol did not increase at all in any of the groups. As a measure of parasympathetic neural activity, independent of sympathetic neural activity, the beat-to-beat variation of the heart rate was calculated. The functional patients had a significantly higher beat-to-beat variation expressed...

  14. Activated and deactivated functional brain areas in the Deqi state A functional MRI study

    Institute of Scientific and Technical Information of China (English)

    Yong Huang; Tongjun Zeng; Guifeng Zhang; Ganlong Li; Na Lu; Xinsheng Lai; Yangjia Lu; Jiarong Chen

    2012-01-01

    We compared the activities of functional regions of the brain in the Deqi versus non-Deqi state,as reported by physicians and subjects during acupuncture.Twelve healthy volunteers received sham and true needling at the Waiguan (TE5) acupoint.Real-time cerebral functional MRI showed that compared with non-sensation after sham needling,true needling activated Brodmann areas 3,6,8,9,10,11,13,20,21,37,39,40,43,and 47,the head of the caudate nucleus,the parahippocampal gyrus,thalamus and red nucleus.True needling also deactivated Brodmann areas 1,2,3,4,5,6,7,9,10,18,24,31,40 and 46.

  15. Blau syndrome : cross-sectional data from a multicentre study of clinical, radiological and functional outcomes

    NARCIS (Netherlands)

    Rose, Carlos D.; Pans, Steven; Casteels, Ingele; Anton, Jordi; Bader-Meunier, Brigitte; Brissaud, Philippe; Cimaz, Roland; Espada, Graciella; Fernandez-Martin, Jorge; Hachulla, Eric; Harjacek, Miroslav; Khubchandani, Raju; Mackensen, Friederike; Merino, Rosa; Naranjo, Antonio; Oliveira-Knupp, Sheila; Pajot, Christine; Russo, Ricardo; Thomee, Caroline; Vastert, SJ; Wulffraat, Nico; Arostegui, Juan I.; Foley, Kevin P.; Bertin, John; Wouters, Carine H.

    2015-01-01

    Objective. To report baseline articular, functional and ocular findings of the first international prospective cohort study of Blau syndrome (BS). Methods. Three-year, multicentre, observational study on articular, functional (HAQ, Childhood HAQ and VAS global and pain), ophthalmological, therapeuti

  16. The Polarized Structure Function $g_{2} A Lattice Study Revisited

    CERN Document Server

    Göckeler, M; Kürzinger, W; Oelrich, H; Rakow, P; Schierholz, G

    1999-01-01

    A recent lattice calculation of the spin-dependent structure function g_2 is revisited. It has been recognized that the twist-three operator, which gives rise to d_2, mixes non-perturbatively with operators of lower dimensions under renormalization. This changes the results substantially.

  17. Platelet function and HIV: a case-control study.

    LENUS (Irish Health Repository)

    Satchell, Claudette S

    2010-03-13

    Cardiovascular disease and myocardial infarction are of increasing concern in HIV-infected populations. Although platelets mediate arterial thrombosis, central to myocardial infarction, data on platelet function in HIV infection are lacking. We hypothesized that HIV-infected patients would have altered platelet reactivity.

  18. Boronate Derivatives of Functionally Diverse Catechols: Stability Studies

    Directory of Open Access Journals (Sweden)

    Kamal Aziz Ketuly

    2010-03-01

    Full Text Available Benzeneboronate of catecholic carboxyl methyl esters, N-acetyldopamine, coumarin and catechol estrogens were prepared as crystalline derivatives in high yield. Related catechol compounds with extra polar functional group(s (OH, NH2 do not form or only partially form unstable cyclic boronate derivatives.

  19. Functional MRI studies in human Ecstasy and cannabis users

    NARCIS (Netherlands)

    Jager, G.

    2006-01-01

    Cannabis and ecstasy are among the most widely used illicit drugs in the world. However, there are substantial concerns about their neurotoxic potential for brain and brain function. Despite previous research, some crucial questions regarding the causality, course and clinical relevance have remaine

  20. Studying the gradient flow coupling in the Schroedinger functional

    Energy Technology Data Exchange (ETDEWEB)

    Fritzsch, P. [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Ramos, A. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

    2013-08-15

    We discuss the setup and features of a new definition of the running coupling in the Schroedinger functional scheme based on the gradient flow. Its suitability for a precise continuum limit in QCD is demonstrated on a set of N{sub f}=2 gauge field ensembles in a physical volume of L{proportional_to}0.4 fm.

  1. Functional Insights into Chromatin Remodelling from Studies on CHARGE Syndrome

    NARCIS (Netherlands)

    Basson, M. Albert; van Ravenswaaij-Arts, Conny

    2015-01-01

    CHARGE syndrome is a rare genetic syndrome characterised by a unique combination of multiple organ anomalies. Dominant loss-of-function mutations in the gene encoding chromodomain helicase DNA binding protein 7 (CHD7), which is an ATP-dependent chromatin remodeller, have been identified as the cause

  2. Studies on the structure and function of pyruvate dehydrogenase complexes

    NARCIS (Netherlands)

    Abreu, de R.A.

    1978-01-01

    The aim of the present investigation was to obtain more information of the structure and function of the pyruvate dehydrogenase complexes from Azotobacter vinelandii and Escherichia coli.In chapter 2 a survey is given of the recent literature on pyruvate dehydrogenase complexes.In chapter 3 results

  3. A parity function for studying the molecular electronic structure

    DEFF Research Database (Denmark)

    Schmider, Hartmut

    1996-01-01

    are qualitatively even more affected by the presence of chemical bonds than a complementary projection, the reciprocal form factor. In this paper we discuss, on the grounds of a variety of examples, how this rather simple function may aid the understanding of the chemical bond on a one-particle level. (C) 1996...

  4. Method for functional study of mitochondria in rat hypothalamus.

    Science.gov (United States)

    Benani, Alexandre; Barquissau, Valentin; Carneiro, Lionel; Salin, Bénédicte; Colombani, Anne-Laure; Leloup, Corinne; Casteilla, Louis; Rigoulet, Michel; Pénicaud, Luc

    2009-04-15

    Different roles of mitochondria in brain function according to brain area are now clearly emerging. Unfortunately, no technique is yet described to investigate mitochondria function in specific brain area. In this article, we provide a complete description of a procedure to analyze the mitochondrial function in rat brain biopsies. Our two-step method consists in a saponin permeabilization of fresh brain tissues in combination with high-resolution respirometry to acquire the integrated respiratory rate of the biopsy. In the first part, we carefully checked the mitochondria integrity after permeabilization, defined experimental conditions to determine the respiratory control ratio (RCR), and tested the reproducibility of this technique. In the second part, we applied our method to test its sensitivity. As a result, this method was sensitive enough to reveal region specificity of mitochondrial respiration within the brain. Moreover, we detected physiopathological modulation of the mitochondrial function in the hypothalamus. Thus this new technique that takes all cell types into account, and does not discard or select any mitochondria sub-population is very suitable to analyze the integrated mitochondrial respiration of brain biopsies.

  5. Mentalizing in schizophrenia: A multivariate functional MRI study.

    Science.gov (United States)

    Martin, Andrew K; Dzafic, Ilvana; Robinson, Gail A; Reutens, David; Mowry, Bryan

    2016-12-01

    Schizophrenia is associated with mentalizing deficits that impact on social functioning and quality of life. Recently, schizophrenia has been conceptualized as a disorder of neural dysconnectivity and network level analyses offers a means of understanding the underlying deficits leading to mentalizing difficulty. Using an established mentalizing task (The Triangles Task), functional magnetic resonance images (fMRI) were acquired from 19 patients with schizophrenia and 17 age- and sex-matched healthy controls (HCs). Participants were required to watch short animations of two triangles interacting with each other with the interactions either random (no interaction), physical (patterned movement), or mental (intentional movement). Task-based Partial Least Squares (PLS) was used to analyze activation differences and commonalities between the three conditions and the two groups. Seed-based PLS was used to assess functional connectivity with peaks identified in the task-based PLS. Behavioural PLS was then performed using the accuracy from the mental conditions. Patients with schizophrenia performed worse on the mentalizing condition compared to HCs. Task-based PLS revealed one significant latent variable (LV) that explained 42.9% of the variance in the task, with theLV separating the mental condition from the physical and random conditions in patients with schizophrenia, but only the mental from physical in healthy controls. The mental animations were associated with increased modulation of the inferior frontal gyri bilaterally, left superior temporal gyrus, right postcentral gyrus, and left caudate nucleus. The physical/random animations were associated with increased modulation of the right medial frontal gyrus and left superior frontal gyrus. Seed-based PLS identified increased functional connectivity with the left inferior frontal gyrus (liFG) and caudate nucleus in patients with schizophrenia, during the mental and physical interactions, with functional connectivity

  6. Study of Validity, Reliability in Accordance with Turkey Conditions in Ego Functions Assessment Scale

    OpenAIRE

    Çevik, Yadigar; Ünsal Barlas, Gül

    2015-01-01

    Objective: In schizophrenia, evaluating ego functions such as disintegration of thought processes, sexual or aggressive behaviour, insufficient occur in various settings. The Ego Function Assessment (EFA) Scale developed by Bellak (1973) allows identifying which ego function is associated with the problematic behaviour and determining the level of function disturbance in patients with schizophrenia. The present study aimed to conduct the validation, reliability and norm study for Ego Function...

  7. Impact of metal-alkoxide functionalized linkers on H2 binding: A density functional study

    Science.gov (United States)

    Banu, Tahamida; Ghosh, Avik; Das, Abhijit K.

    2016-08-01

    The effect of metal-alkoxide functionalization of different organic linkers on the H2 binding is investigated employing DFT approach. While analyzing the H2 binding interaction of magnesium-alkoxide modified benzene, naphthalene, anthracene and pyrene linkers, we find their comparable affinity toward H2 molecules. Six-member alkoxide ring containing naphthalene and pyrene systems interact with the H2 molecules in a comparatively better way than their five-member analogues. AIM, NBO and LMO-EDA analyses have been performed to comprehend the bonding nature between Mg center and the H2 molecules. Polarization along with the charge transfer interactions play significant role in stabilizing the systems.

  8. Functional alignment of regulatory networks: a study of temperate phages.

    Directory of Open Access Journals (Sweden)

    Ala Trusina

    2005-12-01

    Full Text Available The relationship between the design and functionality of molecular networks is now a key issue in biology. Comparison of regulatory networks performing similar tasks can provide insights into how network architecture is constrained by the functions it directs. Here, we discuss methods of network comparison based on network architecture and signaling logic. Introducing local and global signaling scores for the difference between two networks, we quantify similarities between evolutionarily closely and distantly related bacteriophages. Despite the large evolutionary separation between phage lambda and 186, their networks are found to be similar when difference is measured in terms of global signaling. We finally discuss how network alignment can be used to pinpoint protein similarities viewed from the network perspective.

  9. Functional renormalization group studies of nuclear and neutron matter

    CERN Document Server

    Drews, Matthias

    2016-01-01

    Functional renormalization group (FRG) methods applied to calculations of isospin-symmetric and asymmetric nuclear matter as well as neutron matter are reviewed. The approach is based on a chiral Lagrangian expressed in terms of nucleon and meson degrees of freedom as appropriate for the hadronic phase of QCD with spontaneously broken chiral symmetry. Fluctuations beyond mean-field approximation are treated solving Wetterich's FRG flow equations. Nuclear thermodynamics and the nuclear liquid-gas phase transition are investigated in detail, both in symmetric matter and as a function of the proton fraction in asymmetric matter. The equations of state at zero temperature of symmetric nuclear matter and pure neutron matter are found to be in good agreement with advanced ab-initio many-body computations. Contacts with perturbative many-body approaches (in-medium chiral perturbation theory) are discussed. As an interesting test case, the density dependence of the pion mass in the medium is investigated. The questio...

  10. Energetics of cyclohexane isomers: a density-functional study

    CERN Document Server

    Lee, C Y

    1999-01-01

    The binding energies and the geometric structures of conformational isomers of cyclohexane (C sub 6 H sub 1 sub 2) are determined from the density-functional theory combined with ultrasoft pseudopotentials and gradient-corrected nonlocal exchange-correlation functionals. The ground-state chair conformation is found to have a binding energy of 99.457 eV, and the metastable twist-boat conformation has 99.161 eV. The chair conformation converts to another conformation via a half-chair conformation with an energy barrier of 0.507 eV whereas the twist-boat conformation converts to another twist-boat conformation via a boat conformation with a much smaller energy barrier of 0.015 eV.

  11. [Study on an Exoskeleton Hand Function Training Device].

    Science.gov (United States)

    Hu, Xin; Zhang, Ying; Li, Jicai; Yi, Jinhua; Yu, Hongliu; He, Rongrong

    2016-02-01

    Based on the structure and motion bionic principle of the normal adult fingers, biological characteristics of human hands were analyzed, and a wearable exoskeleton hand function training device for the rehabilitation of stroke patients or patients with hand trauma was designed. This device includes the exoskeleton mechanical structure and the electromyography (EMG) control system. With adjustable mechanism, the device was capable to fit different finger lengths, and by capturing the EMG of the users' contralateral limb, the motion state of the exoskeleton hand was controlled. Then driven by the device, the user's fingers conducting adduction/abduction rehabilitation training was carried out. Finally, the mechanical properties and training effect of the exoskeleton hand were verified through mechanism simulation and the experiments on the experimental prototype of the wearable exoskeleton hand function training device.

  12. Techniques and methods to study functional characteristics of emulsion systems

    Directory of Open Access Journals (Sweden)

    Yin-Ting Hu

    2017-01-01

    Full Text Available With the growing popularity of the functional food market, bioactive ingredients from natural sources are discovered one after another for their ability to promote better health and prevent chronic diseases. Emulsion, widely occurring in many food systems, has become a popular vehicle to facilitate the incorporation of bioactive components into the food system. Depending on the designated functionality, an emulsion can be developed with various physical and chemical properties. To ensure the successful development of a high-quality emulsion-based system to serve their purpose in food, knowledge of the analytical methods that could efficiently evaluate their quality parameters is important for investigators who work in this field. In this work, important emulsion properties are overviewed, and techniques that are commonly used to assess them are provided. Discussions and recommendations are also included to make suggestions on advantages and disadvantages when selecting suitable techniques and methods to characterize these quality parameters of emulsion systems.

  13. Dicentric chromosomes: unique models to study centromere function and inactivation

    OpenAIRE

    Kaitlin M Stimpson; Matheny, Justyne E.; Sullivan, Beth A.

    2012-01-01

    Dicentric chromosomes are products of genome rearrangement that place two centromeres on the same chromosome. Depending on the organism, dicentric stability varies after formation. In humans, dicentrics occur naturally in a substantial portion of the population and usually segregate successfully in mitosis and meiosis. Their stability has been attributed to inactivation of one of the two centromeres, creating a functionally monocentric chromosome that can segregate normally during cell divisi...

  14. Comparative study on adhesive performance of functional monomers.

    Science.gov (United States)

    Yoshida, Y; Nagakane, K; Fukuda, R; Nakayama, Y; Okazaki, M; Shintani, H; Inoue, S; Tagawa, Y; Suzuki, K; De Munck, J; Van Meerbeek, B

    2004-06-01

    Mild self-etch adhesives demineralize dentin only partially, leaving hydroxyapatite around collagen within a submicron hybrid layer. We hypothesized that this residual hydroxyapatite may serve as a receptor for chemical interaction with the functional monomer and, subsequently, contribute to adhesive performance in addition to micro-mechanical hybridization. We therefore chemically characterized the adhesive interaction of 3 functional monomers with synthetic hydroxyapatite, using x-ray photoelectron spectroscopy and atomic absorption spectrophotometry. We further characterized their interaction with dentin ultra-morphologically, using transmission electron microscopy. The monomer 10-methacryloxydecyl dihydrogen phosphate (10-MDP) readily adhered to hydroxyapatite. This bond appeared very stable, as confirmed by the low dissolution rate of its calcium salt in water. The bonding potential of 4-methacryloxyethyl trimellitic acid (4-MET) was substantially lower. The monomer 2-methacryloxyethyl phenyl hydrogen phosphate (phenyl-P) and its bond to hydroxyapatite did not appear to be hydrolytically stable. Besides self-etching dentin, specific functional monomers have additional chemical bonding efficacy that is expected to contribute to their adhesive potential to tooth tissue.

  15. Study of Multi-Function Micro-Plasma Spraying Technology

    Institute of Scientific and Technical Information of China (English)

    WANG Liuying; WANG Hangong; HUA Shaochun; CAO Xiaoping

    2007-01-01

    A multi-functional micro-arc plasma spraying system was developed according to aerodynamics and plasma spray theory. The soft switch IGBT (Insulated Gate Bipolar Transistor) invert technique, micro-computer control technique, convergent-divergent nozzle structure and axial powder feeding techniques have been adopted in the design of the micro-arc plasma spraying system. It is not only characterized by a small volume, a light weight, highly accurate control, high deposition efficiency and high reliability, but also has multi-functions in plasma spraying, welding and quenching. The experimental results showed that the system can produce a supersonic flame at a low power, spray Al2O3 particles at an average speed up to 430 m/s, and make nanostructured AT13 coatings with an average bonding strength of 42.7 MPa. Compared to conventional 9M plasma spraying with a higher power, the coatings with almost the same properties as those by conventional plasma spray can be deposited by multi-functional micro-arc plasma spraying with a lower power plasma arc due to an improved power supply design, spray gun structure and powder feeding method. Moreover, this system is suitable for working with thin parts and undertaking on site repairs, and as a result, the application of plasma spraying will be greatly extended.

  16. Executive Functioning and the Metabolic Syndrome: A Project FRONTIER Study

    Science.gov (United States)

    Falkowski, Jed; Atchison, Timothy; DeButte-Smith, Maxine; Weiner, Myron F.; O'Bryant, Sid

    2014-01-01

    Decrements in cognitive functioning have been linked to the metabolic syndrome (MetS), a risk factor for cardiovascular disease defined by the presence of three of the following: elevated blood pressure, increased waist circumference, elevated blood glucose, elevated triglycerides, and low high-density lipoprotein cholesterol. We examined the relationship between four measures of executive functioning (EF) and MetS as diagnosed by National Heart, Lung, and Blood Institute-American Heart Association criteria. MetS was examined in a rural population of 395 persons with a mean age of 61.3 years, 71.4% women, 37.0% Hispanic, 53.7% White non-Hispanic. There was a 61.0% prevalence of MetS. We derived a factor score from the four executive function measures which was used to compare those with and without the syndrome, as well as any additive effects of components of the syndrome. Those with MetS exhibited significantly poorer performance than those without the syndrome. However, there was no additive effect, having more components of the syndrome was not related to lower performance. The presence of MetS was associated with poorer EF in this rural cohort of community dwelling volunteers. PMID:24152591

  17. Study on the synthesis of ceruloplasmin as a functional radioprotector

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Gyu; Kim, Kug Chan; Shim, Hae Won; Lee, Chang Woo; Park, Hyo Kook; Park, Seon Young

    1998-12-01

    Ceruloplasmin is a normal, copper-containing plasma protein that has extracellular antioxidant properties in human and mammals. The in vivo physiological function has not yet been clarified, however, it has been proposed that ceruloplasmin may have a role in oxidation of Fe{sup 2+} to Fe{sup 3+} (ferroxidase) and promotion of lipoprotein oxidation under some circumstances. In this investigation, in addition to the many already known functions of ceruloplasmin, we would like to propose that ceruloplasmin has a thio-linked peroxidase function. The results are followings. 1) Human ceruloplasmin exhibited different antioxidant effects according to the electron donors in a metal-catalyzed oxidation system. 2) Purified ceruloplasmin did not plat a significant role in the protection of DNA stand breaks in the ascorbate/Fe{sup 3+}/O{sub 2} system. However, when ascorbate were replaced with a thiol-reducing equivalent such as dithiothreitol, DNA strand breaks were significantly prevented by the same amount of ceruloplasmin. 3) Human ceruloplasmin showed a potent peroxidase ability to destroy H{sub 2}O{sub 2} in the presence reduced glutathione. 4) Structural integrity may be needed for the glutathione-linked peroxidase activity of human ceruloplasmin. Intact human ceruloplasmin has a potent peroxidase properties to decompose H{sub 2}O{sub 2} in the presence of reduced glutathione.

  18. Equilibrium Properties of Hard Sphere Fluid in Confined Geometries: a Density Functional Theory Study

    Institute of Scientific and Technical Information of China (English)

    李卫华; 诸蔚朝; 马红孺

    2003-01-01

    One component hard-sphere fluid confined in two planar hard walls is studied by means of density functional theory with Rosenfeld functional and molecular dynamics simulation. The validity of the Rosenfeld functional is examined. Chemical potential, grand potential and free energy as functions of the wall separation are obtained.

  19. Graphene functionalization by single atoms doping - a theoretical study

    Science.gov (United States)

    Natan, Amir; Segev, Elad; Hersam, Mark; Seideman, Tamar

    2014-03-01

    We present first principles results and analysis for the electronic structure of chemically modified graphene. We analyze the cases of fluorine adsorption and nitrogen substitution and show that a simple analytical model can describe the doping level as a function of dopant concentration for both cases. We show the relationship between different physical parameters and the electronic band structure of the modified material and its doping level. Finally, we discuss the possible effects of substrate and of different dopant patterns on the band structure and possible applications. amirnatan@post.tau.ac.il

  20. Use of density functional theory in drug metabolism studies

    DEFF Research Database (Denmark)

    Rydberg, Patrik; Jørgensen, Flemming Steen; Olsen, Lars

    2014-01-01

    INTRODUCTION: The cytochrome P450 enzymes (CYPs) metabolize many drug compounds. They catalyze a wide variety of reactions, and potentially, a large number of different metabolites can be generated. Density functional theory (DFT) has, over the past decade, been shown to be a powerful tool...... isoforms. This is probably due to the fact that the binding of the substrates is not the major determinant. When binding of the substrate plays a significant role, the well-known issue of determining the free energy of binding is the challenge. How approaches taking the protein environment into account...

  1. Density Functional Theory Studies of Magnetically Confined Fermi Gas

    Institute of Scientific and Technical Information of China (English)

    陈宇俊; 马红孺

    2001-01-01

    A theory is developed for magnetically confined Fermi gas at a low temperature based on the density functional theory. The theory is illustrated by the numerical calculation of the density distributions of Fermi atoms 40K with parameters according to DeMarco and Jin's experiment [Science, 285(1999)1703]. Our results are in close agreement with the experiment. To check the theory, we also performed calculations using our theory at a high temperature, which compared very well to the results of the classical limit.

  2. Disrupted brain functional network in internet addiction disorder: a resting-state functional magnetic resonance imaging study.

    Directory of Open Access Journals (Sweden)

    Chong-Yaw Wee

    Full Text Available Internet addiction disorder (IAD is increasingly recognized as a mental health disorder, particularly among adolescents. The pathogenesis associated with IAD, however, remains unclear. In this study, we aim to explore the encephalic functional characteristics of IAD adolescents at rest using functional magnetic resonance imaging data. We adopted a graph-theoretic approach to investigate possible disruptions of functional connectivity in terms of network properties including small-worldness, efficiency, and nodal centrality on 17 adolescents with IAD and 16 socio-demographically matched healthy controls. False discovery rate-corrected parametric tests were performed to evaluate the statistical significance of group-level network topological differences. In addition, a correlation analysis was performed to assess the relationships between functional connectivity and clinical measures in the IAD group. Our results demonstrate that there is significant disruption in the functional connectome of IAD patients, particularly between regions located in the frontal, occipital, and parietal lobes. The affected connections are long-range and inter-hemispheric connections. Although significant alterations are observed for regional nodal metrics, there is no difference in global network topology between IAD and healthy groups. In addition, correlation analysis demonstrates that the observed regional abnormalities are correlated with the IAD severity and behavioral clinical assessments. Our findings, which are relatively consistent between anatomically and functionally defined atlases, suggest that IAD causes disruptions of functional connectivity and, importantly, that such disruptions might link to behavioral impairments.

  3. A Comparative Study on Optimal Structural Dynamics Using Wavelet Functions

    Directory of Open Access Journals (Sweden)

    Seyed Hossein Mahdavi

    2015-01-01

    Full Text Available Wavelet solution techniques have become the focus of interest among researchers in different disciplines of science and technology. In this paper, implementation of two different wavelet basis functions has been comparatively considered for dynamic analysis of structures. For this aim, computational technique is developed by using free scale of simple Haar wavelet, initially. Later, complex and continuous Chebyshev wavelet basis functions are presented to improve the time history analysis of structures. Free-scaled Chebyshev coefficient matrix and operation of integration are derived to directly approximate displacements of the corresponding system. In addition, stability of responses has been investigated for the proposed algorithm of discrete Haar wavelet compared against continuous Chebyshev wavelet. To demonstrate the validity of the wavelet-based algorithms, aforesaid schemes have been extended to the linear and nonlinear structural dynamics. The effectiveness of free-scaled Chebyshev wavelet has been compared with simple Haar wavelet and two common integration methods. It is deduced that either indirect method proposed for discrete Haar wavelet or direct approach for continuous Chebyshev wavelet is unconditionally stable. Finally, it is concluded that numerical solution is highly benefited by the least computation time involved and high accuracy of response, particularly using low scale of complex Chebyshev wavelet.

  4. A receiver function study across the Dead Sea Basin (DSB)

    Science.gov (United States)

    Mohsen, A.; Asch, G.; Hofstetter, R.; Kind, R.; Weber, M.

    2008-12-01

    Beginning in September 2006, a temporary network of 30 broadband and 45 short-period seismic stations has been set up on both sides of the Dead Sea Basin (DSB). During one and a half year of successful operation, data were continuously recorded in the field at 100 Hz and 200 Hz sample frequency for the broadband and short-period seismic stations, respectively. The raw data were converted to miniseed format and archived as full seed volume in the GEOFON data center of the GFZ. In the present work, the Receiver Function Method has been applied to the three component passive source data to investigate seismic discontinuities from the crust down to the upper mantle. Unusual negative phases at about 1s delay time have been observed at several stations in the Dead Sea region on the top of the assumed salt diapir. First preliminary receiver function analysis reveals a crustal thickness of about 30 -35 km in the investigated area and possibly low-velocity layer beneath the Moho. It also shows a basin which is possibly filled with salt about 10 km thick beneath the Lisan peninsula (Dead Sea).

  5. Functional renormalization group studies of nuclear and neutron matter

    Science.gov (United States)

    Drews, Matthias; Weise, Wolfram

    2017-03-01

    Functional renormalization group (FRG) methods applied to calculations of isospin-symmetric and asymmetric nuclear matter as well as neutron matter are reviewed. The approach is based on a chiral Lagrangian expressed in terms of nucleon and meson degrees of freedom as appropriate for the hadronic phase of QCD with spontaneously broken chiral symmetry. Fluctuations beyond mean-field approximation are treated solving Wetterich's FRG flow equations. Nuclear thermodynamics and the nuclear liquid-gas phase transition are investigated in detail, both in symmetric matter and as a function of the proton fraction in asymmetric matter. The equations of state at zero temperature of symmetric nuclear matter and pure neutron matter are found to be in good agreement with advanced ab-initio many-body computations. Contacts with perturbative many-body approaches (in-medium chiral perturbation theory) are discussed. As an interesting test case, the density dependence of the pion mass in the medium is investigated. The question of chiral symmetry restoration in nuclear and neutron matter is addressed. A stabilization of the phase with spontaneously broken chiral symmetry is found to persist up to high baryon densities once fluctuations beyond mean-field are included. Neutron star matter including beta equilibrium is discussed under the aspect of the constraints imposed by the existence of two-solar-mass neutron stars.

  6. Study of Magnesium Diboride Clusters Using Hybrid Density Functional Theory

    Directory of Open Access Journals (Sweden)

    D. Rodríguez

    2007-12-01

    Full Text Available Using hybrid density functional theory and a relatively large basis set, the lowest energy equilibrium structure, vibrational spectrum, and natural orbital analysis were obtained for magnesium diboride clusters [(MgB2x for x=1,2, and 3]. For comparison, boron clusters [Bx for x=2,4, and 6] were also considered. The MgB2 and (MgB22 showed equilibrium structures with the boron atoms in arrangements similar to what was obtained for pure boron atoms, whereas, for (MgB23 a different arrangement of boron was obtained. From the population analysis, large electron density in the boron atoms forming the clusters was observed.

  7. Density Function Theory Studies on Reaction of HCS with OH

    Institute of Scientific and Technical Information of China (English)

    PEI Ke-Mei; LI Yi-Min; LI Hai-Yang

    2003-01-01

    The exothermic reaction of HCS with OH on the single-state potential energy surface was explored by means of Density Function Theory(DFT). The equilibrium structural parameters, the harmonic vibrational frequencies, the total energies and the zero point energies(ZPE) of all the species in the reaction were computed. Six intermediates and seven transition states were located, three exothermic channels were found. The frequency analysis and the Intrinsic Reaction Coordinate(IRC) calculation confirm that the transitions are truthful. The results indicate that there are three exothermic channels and their corresponding products are: P1(H2O+CS), P2(H2S+CO), P3(OCS+H2), and P1 has a larger branch ratio.

  8. A DFT study of formaldehyde adsorption on functionalized graphene nanoribbons

    Science.gov (United States)

    Maaghoul, Zohreh; Fazileh, Farhad; Kakemam, Jamal

    2015-02-01

    Density functional theory (DFT) based ab initio calculations were done to monitor the formaldehyde (CHOH) adsorptive behavior on pristine and Ni-decorated graphene sheet. Structural optimization indicates that the formaldehyde molecule is physisorbed on the pristine sheet via partly weak van der Waals attraction having the adsorption energy of about -15.7 kcal/mol. Metal decorated sheet is able to interact with the CHOH molecule, so that single Ni atoms prefer to bind strongly at the bridge site of graphene and each metal atom bound on sheet may adsorb up to four CHOH. The findings also show that the Ni decoration on graphene surface results in some changes in electronic properties of the sheet and its Eg is remained unchanged after adsorption of CHOH molecules. It is noteworthy to say that no bond cleavage was observed for the adsorption of CHOH on Ni-decorated graphene.

  9. Density functional theory studies of HCOOH decomposition on Pd(111)

    Science.gov (United States)

    Scaranto, Jessica; Mavrikakis, Manos

    2016-08-01

    The investigation of formic acid (HCOOH) decomposition on transition metal surfaces is important to derive useful insights for vapor phase catalysis involving HCOOH and for the development of direct HCOOH fuel cells (DFAFC). Here we present the results obtained from periodic, self-consistent, density functional theory (DFT-GGA) calculations for the elementary steps involved in the gas-phase decomposition of HCOOH on Pd(111). Accordingly, we analyzed the minimum energy paths for HCOOH dehydrogenation to CO2 + H2 and dehydration to CO + H2O through the carboxyl (COOH) and formate (HCOO) intermediates. Our results suggest that HCOO formation is easier than COOH formation, but HCOO decomposition is more difficult than COOH decomposition, in particular in the presence of co-adsorbed O and OH species. Therefore, both paths may contribute to HCOOH decomposition. CO formation goes mainly through COOH decomposition.

  10. Semiotic aspects of human nonverbal vocalizations: a functional imaging study.

    Science.gov (United States)

    Dietrich, Susanne; Hertrich, Ingo; Alter, Kai; Ischebeck, Anja; Ackermann, Hermann

    2007-12-03

    Humans produce a variety of distinct nonverbal vocalizations. Whereas affective bursts, for example, laughter, have an intrinsic communicative role bound to social behavior, vegetative sounds, for example, snoring, just signal autonomic-physiological states. However, the latter events, for example, belching, may also be used as intentional communicative actions (vocal gestures), characterized by an arbitrary culture-dependent sound-to-meaning (semiotic) relationship, comparable to verbal utterances. Using a decision task, hemodynamic responses to affective bursts, vegetative sounds, and vocal gestures were measured by means of functional magnetic resonance imaging. Affective bursts elicited activation of anterior left superior temporal gyrus. In contrast, arbitrary vocal gestures yielded hemodynamic reactions of the left temporo-parietal junction. Conceivably, a listener's interpretation of nonverbal utterances as intentional events depends upon a left-hemisphere temporo-parietal 'auditory-to-meaning interface' related to our mechanisms of speech processing.

  11. Density functional study of ferromagnetism in alkali metal thin films

    Indian Academy of Sciences (India)

    Prasenjit Sen

    2010-04-01

    Electronic and magnetic structures of (1 0 0) films of K and Cs, having thicknesses of one to seven layers, are calculated within the plane-wave projector augmented wave (PAW) formalism of the density functional theory (DFT), using both local spin density approximation (LSDA) and the PW91 generalized gradient approximation (GGA). Only a six-layer Cs film is found to have a ferromagnetic (FM) state which is degenerate with a paramagnetic (PM) state within the accuracy of these calculations. These results are compared with those obtained from calculations on a finite-thickness uniform jellium model (UJM), and it is argued that within LSDA or GGA, alkali metal thin films cannot be claimed to have an FM ground state. Relevance of these results to the experiments on transition metal-doped alkali metal thin films and bulk hosts are also discussed.

  12. Functional magnetic resonance imaging study on dysphagia after unilateral hemispheric stroke: a preliminary study.

    Science.gov (United States)

    Li, S; Luo, C; Yu, B; Yan, B; Gong, Q; He, C; He, L; Huang, X; Yao, D; Lui, S; Tang, H; Chen, Q; Zeng, Y; Zhou, D

    2009-12-01

    Swallowing dysfunction is common and disabling after acute stroke; however, the mechanism of dysphagia or recovery of swallowing from dysphagia remains uncertain. The purpose of this study was to explore cerebral activation of swallowing in dysphagia using functional MRI (fMRI) to compare the functional anatomy of swallowing in unilateral hemispheric stroke patients and healthy adults. In total, five left hemispheric stroke patients with dysphagia, five right hemispheric stroke patients with dysphagia and 10 healthy controls were examined with event related fMRI while laryngeal swallow related movements were recorded. Data were processed using the general linear model. A multifocal cerebral representation of swallowing was identified predominantly in the left hemisphere, in a bilateral and asymmetrical manner. Cerebral activation during swallowing tasks was localised to the precentral, postcentral and anterior cingulate gyri, insula and thalamus in all groups. Activation of volitional swallowing in dysphagic unilateral hemispheric stroke patients might require reorganisation of the dominant hemispheric motor cortex, or a compensatory shift in activation to unaffected areas of the hemisphere. The results indicate that unilateral stroke of either cerebral hemisphere can produce dysphagia. Effective recovery is associated with cerebral activation related to cortical swallowing representation in the compensating or recruited areas of the intact hemisphere. Functional MRI is a useful method for exploring the spatial localisation of changes in neuronal activity during tasks that may be related to recovery. Therefore, the subsequent information gleaned from changes in neural plasticity could be useful for assessing the prognosis of dysphagic stroke.

  13. Effects of electroconvulsive therapy on amygdala function in major depression - a longitudinal functional magnetic resonance imaging study.

    Science.gov (United States)

    Redlich, R; Bürger, C; Dohm, K; Grotegerd, D; Opel, N; Zaremba, D; Meinert, S; Förster, K; Repple, J; Schnelle, R; Wagenknecht, C; Zavorotnyy, M; Heindel, W; Kugel, H; Gerbaulet, M; Alferink, J; Arolt, V; Zwanzger, P; Dannlowski, U

    2017-09-01

    Electroconvulsive therapy (ECT) is one of the most effective treatments for severe depression. However, little is known regarding brain functional processes mediating ECT effects. In a non-randomized prospective study, functional magnetic resonance imaging data during the automatic processing of subliminally presented emotional faces were obtained twice, about 6 weeks apart, in patients with major depressive disorder (MDD) before and after treatment with ECT (ECT, n = 24). Additionally, a control sample of MDD patients treated solely with pharmacotherapy (MED, n = 23) and a healthy control sample (HC, n = 22) were obtained. Before therapy, both patient groups equally showed elevated amygdala reactivity to sad faces compared with HC. After treatment, a decrease in amygdala activity to negative stimuli was discerned in both patient samples indicating a normalization of amygdala function, suggesting mechanisms potentially unspecific for ECT. Moreover, a decrease in amygdala activity to sad faces was associated with symptomatic improvements in the ECT sample (r spearman = -0.48, p = 0.044), and by tendency also for the MED sample (r spearman = -0.38, p = 0.098). However, we did not find any significant association between pre-treatment amygdala function to emotional stimuli and individual symptom improvement, neither for the ECT sample, nor for the MED sample. In sum, the present study provides first results regarding functional changes in emotion processing due to ECT treatment using a longitudinal design, thus validating and extending our knowledge gained from previous treatment studies. A limitation was that ECT patients received concurrent medication treatment.

  14. Altered small-world efficiency of brain functional networks in acupuncture at ST36: a functional MRI study.

    Directory of Open Access Journals (Sweden)

    Bo Liu

    Full Text Available BACKGROUND: Acupuncture in humans can produce clinical effects via the central nervous system. However, the neural substrates of acupuncture's effects remain largely unknown. RESULTS: We utilized functional MRI to investigate the topological efficiency of brain functional networks in eighteen healthy young adults who were scanned before and after acupuncture at the ST36 acupoints (ACUP and its sham point (SHAM. Whole-brain functional networks were constructed by thresholding temporal correlations matrices of ninety brain regions, followed by a graph theory-based analysis. We showed that brain functional networks exhibited small-world attributes (high local and global efficiency regardless of the order of acupuncture and stimulus points, a finding compatible with previous studies of brain functional networks. Furthermore, the brain networks had increased local efficiency after ACUP stimulation but there were no significant differences after SHAM, indicating a specificity of acupuncture point in coordinating local information flow over the whole brain. Moreover, significant (P<0.05, corrected by false discovery rate approach effects of only acupuncture point were detected on nodal degree of the left hippocampus (higher nodal degree at ACUP as compared to SHAM. Using an uncorrected P<0.05, point-related effects were also observed in the anterior cingulate cortex, frontal and occipital regions while stimulation-related effects in various brain regions of frontal, parietal and occipital cortex regions. In addition, we found that several limbic and subcortical brain regions exhibited point- and stimulation-related alterations in their regional homogeneity (P<0.05, uncorrected. CONCLUSIONS: Our results suggest that acupuncture modulates topological organization of whole-brain functional brain networks and the modulation has point specificity. These findings provide new insights into neuronal mechanism of acupuncture from the perspective of functional

  15. Executive Functions in Preschool Children With ADHD and DBD : An 18-Month Longitudinal Study

    NARCIS (Netherlands)

    Schoemaker, Kim; Bunte, Tessa; Espy, Kimberly Andrews; Dekovic, Maja; Matthys, Walter

    2014-01-01

    In this longitudinal study, we examined the stability of the association between executive functions and externalizing behavior problems, and the developmental change of executive functions in a predominately clinically diagnosed preschool sample (N = 200). Inhibition and working memory performance

  16. Functional MRI in pre-surgical planning: case study and cautionary ...

    African Journals Online (AJOL)

    Functional MRI in pre-surgical planning: case study and cautionary notes. ... Since its inception almost 20 years ago, functional magnetic resonance imaging ... Although the clinical applications of fMRI are still limited, there have recently been ...

  17. Executive Functions in Preschool Children With ADHD and DBD : An 18-Month Longitudinal Study

    NARCIS (Netherlands)

    Schoemaker, Kim; Bunte, Tessa; Espy, Kimberly Andrews; Dekovic, Maja; Matthys, Walter

    2014-01-01

    In this longitudinal study, we examined the stability of the association between executive functions and externalizing behavior problems, and the developmental change of executive functions in a predominately clinically diagnosed preschool sample (N = 200). Inhibition and working memory performance

  18. Diet quality and markers of endothelial function: The CARDIA study

    NARCIS (Netherlands)

    Sijtsma, F.P.C.; Meyer, K.A.; Steffen, L.M.; Horn, van L.; Shikany, J.M.; Odegaard, A.O.; Gross, M.D.; Kromhout, D.; Jacobs, D.R.

    2014-01-01

    Background and aim: Dietary patterns are associated cross-sectionally with cellular adhesion molecules (CAMs). We studied prospective associations of three dietary patterns with CAMs. Methods and results: In the Coronary Artery Risk Development in Young Adults (CARDIA) study, diet was assessed at ye

  19. One output function: a misconception of students studying digital systems - a case study

    Science.gov (United States)

    Trotskovsky, E.; Sabag, N.

    2015-05-01

    Background:Learning processes are usually characterized by students' misunderstandings and misconceptions. Engineering educators intend to help their students overcome their misconceptions and achieve correct understanding of the concept. This paper describes a misconception in digital systems held by many students who believe that combinational logic circuits should have only one output. Purpose:The current study aims to investigate the roots of the misconception about one-output function and the pedagogical methods that can help students overcome the misconception. Sample:Three hundred and eighty-one students in the Departments of Electrical and Electronics and Mechanical Engineering at an academic engineering college, who learned the same topics of a digital combinational system, participated in the research. Design and method:In the initial research stage, students were taught according to traditional method - first to design a one-output combinational logic system, and then to implement a system with a number of output functions. In the main stage, an experimental group was taught using a new method whereby they were shown how to implement a system with several output functions, prior to learning about one-output systems. A control group was taught using the traditional method. In the replication stage (the third stage), an experimental group was taught using the new method. A mixed research methodology was used to examine the results of the new learning method. Results:Quantitative research showed that the new teaching approach resulted in a statistically significant decrease in student errors, and qualitative research revealed students' erroneous thinking patterns. Conclusions:It can be assumed that the traditional teaching method generates an incorrect mental model of the one-output function among students. The new pedagogical approach prevented the creation of an erroneous mental model and helped students develop the correct conceptual understanding.

  20. The role of Riemann generalized derivative in the study of qualitative properties of functions

    Directory of Open Access Journals (Sweden)

    Sorin Radulescu

    2013-08-01

    Full Text Available Marshal Ash [3] introduced the concept of (sigma,tau differentiable functions and studied the Riemann generalized derivatives In this article we study the convexity and monotonicity of (sigma,tau differentiable functions, using results by Hincin, Humke and Laczkovich, and using the Riemann generalized derivative. We give conditions such that the classic properties of differentiable functions hold also for (sigma,tau differentiable functions.

  1. Relationship between linguistic functions and cognitive functions in a clinical study of Chinese patients with post-stroke aphasia

    Institute of Scientific and Technical Information of China (English)

    YU Zeng-zhi; JIANG Shu-jun; BI Sheng; LI Jun; LEI Di; SUN Li-ling

    2013-01-01

    Background There has been a long debate among scholars surrounding the relationship between language and cognition.The worldwide study of aphasia is actively exploring the function of language from cognitive point of view.This study aimed to investigate the relationship between linguistic functions and cognitive functions in a clinical study of Chinese patients with post-stroke aphasia.Methods Cognitive functions of 63 Chinese patients with aphasia following a stroke were assessed with the Chinese version of the second edition of Loewenstein Occupational Therapy Cognitive Assessment (LOTCA) battery and their linguistic functions were tested with the Western Aphasia Battery (WAB) Scale,respectively.The correlation between the results observed on the LOTCA battery and those on the WAB was analyzed.Aphasia quotient,performance quotient,cortical quotient,and linguistic function of the patients were compared.Then,each language function was analyzed by way of dependent adopt multiple regression analysis.Results The total score of 63 patients as shown on the LOTCA battery was significantly correlated with the aphasia quotient,performance quotient,and cortical quotient observed on the WAB Scale (P <0.05,P <0.01).However,the correlation between visuomotor organization under LOTCA and repeat under WAB was not significant (P >0.05).The attention of LOTCA and WAB's spontaneous speech,repeat,naming,and aphasia quotient was not relevant either (P>0.05).In addition,correlations between the results observed on the LOTCA battery and the WAB were significant (P<0.05,P <0.01).Among the significant variables finally entered into the standardized canonical discriminant functions,main factors affected the aphasia.Multiple regression analysis showed that orientation,spatial perception,and visual perception had a notable influence on aphasia quotient and naming.Orientation and thinking operation was found to have a notable influence on spontaneous speech.Spatial perception and

  2. Functional study on two artificial liver bioreactors with collagen gel

    Directory of Open Access Journals (Sweden)

    XU Bing

    2014-10-01

    Full Text Available ObjectiveTo improve the hollow fiber bioreactor of artificial liver. MethodsRat hepatocytes mixed with collagen solution were injected into the external cavity of a hollow fiber reactor to construct a bioreactor of hepatocytes suspended in collagen gel (group Ⅰ. Other rat hepatocytes suspended in solution were injected into the external cavity of a hollow fiber reactor with a layer of collagen on the wall of the external cavity to construct a bioreactor of collagen layer and hepatocytes (group Ⅱ. For each group, the culture solution circulated through the internal cavity of the hollow fiber bioreactor; the bioreactor was put in a culture box for 9 d, and the culture solution in the internal cavity was exchanged for new one every 24 h; the concentrations of albumin (Alb, urea, and lactate dehydrogenase (LDH in the culture solution samples were measured to examine the hepatocyte function of the bioreactor. Statistical analysis was performed using SPSS 130. Continuous data were expressed as mean±SD, and comparison between groups was made by paired t test. ResultsFor groups Ⅰ and Ⅱ, Alb levels reached peak values on day 3 of culture (1.41±0.08 g/L and 0.65±0.05 g/L; from day 3 to 9, group I had a significantly higher Alb level than group Ⅱ (t>7.572, P<0.01. For groups Ⅰ and Ⅱ, urea levels reached peak values on days 3 and 5 of culture (1.73±0.14 mmol/L and 1.56±0.18 mmol/L; from days 5 to 9, group I had a significantly higher urea level than group Ⅱ (t>8.418, P<0.01. For groups Ⅰ and Ⅱ, LDH levels reached peak values on day 9 of culture (32.03±9.13 U/L and 70.17±25.28 U/L; from days 1 to 9, group I had a significantly lower LDH level than group Ⅱ(t>5.633, P<0.01. Therefore, the bioreactor of hepatocytes suspended in collagen gel (group Ⅰ showed a better hepatocyte function and less hepatic enzyme leakage compared with the bioreactor of collagen layer and hepatocytes (group Ⅱ. Conclusion

  3. United abominations: Density functional studies of heavy metal chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Schoendorff, George [Iowa State Univ., Ames, IA (United States)

    2012-01-01

    Carbonyl and nitrile addition to uranyl (UO22+) are studied. The competition between nitrile and water ligands in the formation of uranyl complexes is investigated. The possibility of hypercoordinated uranyl with acetone ligands is examined. Uranyl is studied with diactone alcohol ligands as a means to explain the apparent hypercoordinated uranyl. A discussion of the formation of mesityl oxide ligands is also included. A joint theory/experimental study of reactions of zwitterionic boratoiridium(I) complexes with oxazoline-based scorpionate ligands is reported. A computational study was done of the catalytic hydroamination/cyclization of aminoalkenes with zirconium-based catalysts. Techniques are surveyed for programming for graphical processing units (GPUs) using Fortran.

  4. Pulmonary function studies in young healthy Malaysians of Kelantan, Malaysia

    National Research Council Canada - National Science Library

    Bandyopadhyay, Amit

    2011-01-01

    ... (64 males, 64 females) non-smoking healthy young subjects were randomly sampled for the study from the Kelantanese students' population of the University Sains Malaysia, Kota Bharu Campus, Kelantan, Malaysia...

  5. Impact of contamination with long-lived radionuclides on PET kinetics modelling in multitracer studies

    DEFF Research Database (Denmark)

    Jødal, Lars; Hansen, Søren Baarsgaard; Jensen, Svend B

    2016-01-01

    Introduction: An important issue in multitracer studies is the separation of signals from the different radiotracers. This is especially the case when an early tracer has a long physical half-life and kinetic modelling has to be performed, because the early tracer can confer a long-lived contamin...

  6. Study on Correlation between Neuropeptide and Functional Hypothalamic Amenorrhea

    Institute of Scientific and Technical Information of China (English)

    陈晓燕; 吕淑兰; 曹缵孙; 毛文军; 宋青

    2001-01-01

    Objective To explore the correlation between neuropeptide and functional hypothalam ic amenorrhea (FHA)Materials & Methods The basic and GnRH-stimulated levels of serum FSH, LH and plasma β-endorphin (β-EP), somatostatin (SS) in 33 patients with FHA and 17 women with normal menstrual cycles were tested by RIA.Results β-EP level in FHA group was significantly higher than that in control group and had a negative correlation with FSH and LH. The basic SS level in FHA group had no significant difference compared with the control group, but it had negative correlation with LH and no correlation with FSH. β-EP level in FHA group decreased after being stimulated with GnRH, and reached its minimum value after 15 min, then gradually rose back to the basic level. β-EP level in control group had no regular changes. SS level in both group did not change obviously.Conclusion The increased level of β-EP may play an important role in FHA. GnRH can inhibit β-EP level to some extent, while the effect of SS on FHA deserve further research.

  7. Study of thymidylate synthetase-function by laser Raman spectroscopy.

    Science.gov (United States)

    Sharma, R K; Kisliuk, R L; Verma, S P; Wallach, D F

    1975-05-23

    The Laser-Raman spectra of thymidylate synthetase have been obtained with 488 nm excitation from an argon ion laser. Raman bands observed in the range 600-800 cm-minus-1 have been assigned to functional groups of constituent amino acids. The band positions and intensities in the Amide I (1600-1700 cm-minus-1) and Amide III (1200-1300 cm-minus-1) regions, suggest that the enzyme is a mixture of alpha-helical and unordered conformations. Low levels of beta-structure cannot be excluded. The spectra of the ternary complex formed by reacting thymidylate synthetase with (+)-L-methylenetetrahydrofolate and fluorodeoxyuridylate reveals a new band at 1618 cm-minus-1 assigned to the C=N stretching vibration. This band may be due to formation of dihydrofolate or an iminium ion. The overall secondary structure of thymidylate synthetase does not change on formation of the ternary complex. However, the spectrum of the complex indicates local changes in groups such as ionized carboxyl (1400 cm-minus-1), tryptophan (1003 cm-minus-1) and CH-3, CH-2 deformation modes (1440-1470 cm-minus-1).

  8. Chiroptical Properties of Amino Acids: A Density Functional Theory Study

    Directory of Open Access Journals (Sweden)

    Martine Adrian-Scotto

    2010-04-01

    Full Text Available Amino acids are involved in many scientific theories elucidating possible origins of life on Earth. One of the challenges when discussing the evolutionary origin of biopolymers such as proteins and oligonucleotides in living organisms is the phenomenon that these polymers implement monomers of exclusively one handedness, a feature called biomolecular homochirality. Many attempts have been made to understand this process of racemic symmetry breaking. Assuming an extraterrestrial origin of the molecular building blocks of living organisms, their susceptibility to asymmetric photolysis by the absorption of circularly polarized electromagnetic radiation in interstellar space was proposed. In order to predict whether the interaction of circularly polarized light with various racemic amino acids can induce an enantiomeric excess, we investigated the electronic and chiroptical properties of the amino acids valine and isovaline by a molecular modelling approach based on quantum chemistry (Density Functional Theory. The average spectra of both L-valine and L-isovaline have been produced on the basis of Boltzmann population analysis using computed spectra for the various conformations of each amino acid.

  9. Embedding germanium in graphene: A density functional theory study

    Science.gov (United States)

    Xu, Zhuo; Li, Yangping; Tan, Tingting; Liu, Zhengtang

    2017-03-01

    Based on the density functional theory, we investigate the structural, electronic, and magnetic properties of graphene sheet with substitutional Ge atoms in both single and double vacancies, and graphene sheet with Ge-chain impurity. We find the substitutional Ge is chemically bonded to graphene, and is more stable in the double vacancy site. The electronic properties indicate that metallic and semiconductor states with a range of band gaps from 0 to 0.87 eV could be obtained depending on different substitution sites, concentrations, and vacancy types. Magnetic moment is observed in graphene with single vacancy. Tunable electronic behaviors are also observed in graphene sheet with Ge-chain impurity, and a magnetic moment of 2.9 μB is observed in single Ge-chain incorporated 4 × 4 graphene supercell. From these investigations, we conclude that by doping of Ge in vacancy-contained graphene, it could provide great advantages for its application in future nanoscale devices.

  10. The functional neuroanatomy of object agnosia: a case study.

    Science.gov (United States)

    Konen, Christina S; Behrmann, Marlene; Nishimura, Mayu; Kastner, Sabine

    2011-07-14

    Cortical reorganization of visual and object representations following neural injury was examined using fMRI and behavioral investigations. We probed the visual responsivity of the ventral visual cortex of an agnosic patient who was impaired at object recognition following a lesion to the right lateral fusiform gyrus. In both hemispheres, retinotopic mapping revealed typical topographic organization and visual activation of early visual cortex. However, visual responses, object-related, and -selective responses were reduced in regions immediately surrounding the lesion in the right hemisphere, and also, surprisingly, in corresponding locations in the structurally intact left hemisphere. In contrast, hV4 of the right hemisphere showed expanded response properties. These findings indicate that the right lateral fusiform gyrus is critically involved in object recognition and that an impairment to this region has widespread consequences for remote parts of cortex. Finally, functional neural plasticity is possible even when a cortical lesion is sustained in adulthood. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Density Functional Theory Study of Spirodienone Stereoisomers in Lignin

    Energy Technology Data Exchange (ETDEWEB)

    Elder, Thomas [USDA-Forest; Berstis, Laura [National; Biosciences; Beckham, Gregg T. [National; Crowley, Michael F. [National; Biosciences

    2017-07-10

    The spirodienone structure in lignin is a relatively recent discovery, and it has been found to occur in lignin of various plant species at concentrations of ~3%, which is sufficiently high to be important for better understanding of its properties and reactivity. The cyclic structure, with a ..beta..-1 bond, has been proposed to be a precursor for acyclic ..beta..-1 linkages in lignin. Previous analytical work has revealed the presence, but not the absolute configuration, of two stereoisomeric forms of spirodienone. The objective of the current work was to determine if there are thermodynamic differences that could help identify the experimentally observed stereoisomers. Results from density functional theory calculations reveal the presence of clusters of stereoisomers with varying stability that may be of use in narrowing the list of possible structures. Furthermore, the bond dissociation enthalpy of the cyclic ring exhibited a particularly high value for the C-O cleavage reaction relative to more conventional ether bonds in lignin, perhaps due to limited electron delocalization possibilities.

  12. Clustering of protein domains for functional and evolutionary studies

    Directory of Open Access Journals (Sweden)

    Long Paul F

    2009-10-01

    Full Text Available Abstract Background The number of protein family members defined by DNA sequencing is usually much larger than those characterised experimentally. This paper describes a method to divide protein families into subtypes purely on sequence criteria. Comparison with experimental data allows an independent test of the quality of the clustering. Results An evolutionary split statistic is calculated for each column in a protein multiple sequence alignment; the statistic has a larger value when a column is better described by an evolutionary model that assumes clustering around two or more amino acids rather than a single amino acid. The user selects columns (typically the top ranked columns to construct a motif. The motif is used to divide the family into subtypes using a stochastic optimization procedure related to the deterministic annealing EM algorithm (DAEM, which yields a specificity score showing how well each family member is assigned to a subtype. The clustering obtained is not strongly dependent on the number of amino acids chosen for the motif. The robustness of this method was demonstrated using six well characterized protein families: nucleotidyl cyclase, protein kinase, dehydrogenase, two polyketide synthase domains and small heat shock proteins. Phylogenetic trees did not allow accurate clustering for three of the six families. Conclusion The method clustered the families into functional subtypes with an accuracy of 90 to 100%. False assignments usually had a low specificity score.

  13. STUDY OF INDICATION, COMPLICATION AND FUNCTIONAL OUTCOME IN ENDOSCOPIC SEPTOPLASTY

    Directory of Open Access Journals (Sweden)

    Ritesh

    2014-03-01

    Full Text Available Introduction of nasal endoscope has revolutionized the field of rhinology. Endoscopic septoplasty is a minimally invasive technique that helps us to correct the deformity of the septum under excellent direct visualization using an endoscope. AIMS: Studied indication, technique result and complication of endoscopic septoplasty. METHODS AND MATERIAL: It was a prospective study carried out at our institute from August 2011 to December 2013 RESULTS: 57 patients having nasal obstruction were selected for the study. In present study 24(42.1% patients had only cartilagenous deviation, 9(15.7% patients had bony deviation, 15(26.3% had both bony and cartilage deviation, while 12(21% had spur and 5(8.7% had caudal dislocation. Minor complications were seen during study, no major occurred during endoscopic septoplasty or post- operative period. In 40(70% cases endoscopic septoplasty was performed as primary procedure and in 9(15.7% cases performed as conjugation with FESS, also in 8(14% patients septoplasty performed prior to endonasal DCR for good assess to lateral nasal. CONCLUSIONS: Endoscopic septoplasty is an effective technique that can be performed safely alone or in combination with endoscopic sinus surgery. It reduces the complication, hospital stay and has fast recovery of the patients postoperatively. It facilitates accurate identification of the pathology, and it is associated with significant reduction in patient’s morbidity in the postoperative period

  14. Neutron scatter studies of chromatin structures related to functions

    Energy Technology Data Exchange (ETDEWEB)

    Bradbury, E.M.

    1992-01-01

    Despite of setbacks in the lack of neutrons for the proposed We have made considerable progress in chromatin reconstitution with the VLR histone H1/H5 and in understanding the dynamics of nucleosomes. A ferromagnetic fluid was developed to align biological molecules for structural studies using small-angle-neutron-scattering. We have also identified and characterized an intrinsically bent DNA region flanking the RNA polymerase I binding site of the ribosomal RNA gene in Physarum Polycephalum. Finally projects in progress are in the areas of studying the interatctions of histone H4 amino-terminus peptide 1-23 and acetylated 1-23 peptide with DNA using thermal denaturation; study of GGAAT repeats found in human centromeres using high resolution Nuclear magnetic Resonance and nuclease sentivity assay; and the role of histones and other sperm specific proteins with sperm chromatin.

  15. Neutron scatter studies of chromatin structures related to functions

    Energy Technology Data Exchange (ETDEWEB)

    Bradbury, E.M.

    1992-01-01

    We have made considerable progress in chromatin reconstitution with very lysine rich histone H1/H5 and in understanding the dynamics of nucleosomes. A ferromagnetic fluid was developed to align biological molecules for structural studies using small-angle-neutron-scattering. We have also identified and characterized in intrinsically bent DNA region flaking the RNA polymerase I binding site of the ribosomal RNA gene in Physarum Polycephalum. Finally projects in progress are in the areas of studying the interactions of histone H4 amino-terminus peptide 1-23 and acetylated 1-23 peptide with DNA using thermal denaturation; study of GGAAT repeats found in human centromeres using high resolution Nuclear Magnetic Resonance and nuclease sentivity assay; and the role of histones and other sperm specific proteins with sperm chromatin.

  16. Reconstructed human epidermis: A model to study the barrier function

    Science.gov (United States)

    Barbotteau, Y.; Gontier, E.; Barberet, P.; Cappadoro, M.; De Wever, B.; Habchi, C.; Incerti, S.; Mavon, A.; Moretto, P.; Pouthier, T.; Smith, R. W.; Ynsa, M. D.

    2005-04-01

    The use of in vitro reconstructed human epidermis (RHE) by the cosmetic and pharmaceutical industries is increasing because of its similar physiological mechanisms to native human skin. With the advent of ethic laws on animal experimentation, RHE provides an helpful alternative for the test of formulations. The aim of this study is to check that the RHE mineral status is comparable to that of human native skin by investigating the elemental distributions in the epidermis strata. In addition, possible deleterious effects of the transport on the epidermis ionic content were studied by nuclear microscopy.

  17. Structure and Function Study of Phi29 DNA packaging motor

    Science.gov (United States)

    Fang, Huaming

    molecules were required to bind to one short dsDNA molecule. The inhibitive curve of Walker B mutant gp16 analyzed by binomial distribution model showed that one inactive mutant gp16 in the gp16 ring could block the function of the motor and the stoichiometry of gp16 was six. These findings facilitate our understanding of the molecular mechanism of viral DNA packaging: a novel viral DNA packaging model "push through a one-way valve" was proposed. In this model, the connector functioned as a valve to allow DNA to enter but prevented it from sliding out during DNA packaging; the six subunits in the gp16 ring acted sequentially to push DNA into the connector channel. ATP binding of gp16 induced a conformation change with a high affinity for dsDNA. Then, the ATP was hydrolyzed which resulted in the movement of subdomains in this individual gp16 subunit and DNA was pushed forward, followed by the double helix of dsDNA being brought forward to the adjacent subunit in the gp16 ring. The elucidation of the viral DNA packaging mechanism holds great potential for developing artificial motors for delivering drugs and other molecular cargos.

  18. Density-functional study of U-Mo alloys

    Science.gov (United States)

    Landa, Alexander; Soderlind, Per; Turchi, Patrice E. A.

    2011-03-01

    The U-Mo and U-Zr alloys proved to be very promising fuels for advanced fast nuclear reactors. According to numerous experiments, the main advantages of U-Mo fuels over U-Zr fuels lies in a much lower constituent redistribution due to the existence a single γ -U-Mo phase with body-centered cubic structure over typical fuel operation temperatures. Density-functional theory (EMTO-CPA technique) previously used to describe phase equilibria in U-Zr alloys [A. Landa, P. Söderlind, P. E. A. Turchi, Journal of Alloys and Compounds, 478 (2009) 103] is extended to investigate the ground-state properties of U-Mo solid solutions. Calculated heats of formation of bcc U-Zr and U-Mo alloys are compared with CALPHAD assessments. We discuss how the heat of formation in both alloys correlates with the charge transfer between the alloy components, and how the specific behavior of the density of states in the vicinity of the Fermi level promotes the stabilization of the U2 Mo compound. Our calculations prove that, due to the existence of a single γ -phase over the typical fuel operation temperatures, γ -U-Mo alloys should indeed have much lower constituent redistribution than γ -U-Zr alloys for which binodal decomposition causes a high degree of constituent redistribution. This work was performed under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  19. Functional brain imaging studies of youth depression: A systematic review

    Directory of Open Access Journals (Sweden)

    Rebecca Kerestes

    2014-01-01

    Conclusions: Youth MDD is characterized by abnormal activations in ventromedial frontal regions, the anterior cingulate and amygdala, which are broadly consistent with the implicated role of medial network regions in the pathophysiology of depression. Future longitudinal studies examining the effects of neurodevelopmental changes and pubertal maturation on brain systems implicated in youth MDD will provide a more comprehensive neurobiological model of youth depression.

  20. Bovine lactotroph cultures for the study of prolactin synthesis functions.

    Science.gov (United States)

    Wang, Jianfa; Yang, Zhanqing; Fu, Shoupeng; Liu, Bingrun; Wu, Dianjun; Wang, Wei; Sun, Dongbo; Wu, Rui; Liu, Juxiong

    2016-03-01

    The aim of this study was to establish a bovine anterior pituitary-derived lactotroph (BAPDL) line that expresses prolactin (PRL) in vitro to study the mechanisms of bovine PRL synthesis and secretion. Immunohistochemistry assay of PRL in the newborn calves' anterior pituitary glands showed that most lactotrophs were located within the superior border of the lateral wings of the anterior pituitary. Tissues of the superior border of the lateral wings of the anterior pituitary were dispersed and cultured in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% fetal bovine serum (FBS). The limiting dilution method was used to establish BAPDL from single cell clone. BAPDL cells constantly expressed mRNAs for PRL and pituitary-specific transcription factor 1 (Pit-1) gene and grew steadily and rapidly in the DMEM supplemented with 10% FBS. PRL immunoreactivity was present in BAPDL at passage 20. The concentration of bovine PRL in BAPDL at passage 20 culture supernatant was decreased to below 35% compared with that in BAPDL at passage 1. The effects of human epidermal growth factor (hEGF) and dopamine (DA) on the expression and secretion of PRL in BAPDL at passage 4 were also investigated. The results are consistent with those of previous studies. Thus, it can be used successfully for studying the mechanisms of stimuli regulating PRL synthesis and release.

  1. Functional genomics to study protein secretion stress in Aspergillus niger

    NARCIS (Netherlands)

    Silva Pinheiro Carvalho, Neuza Daniela

    2011-01-01

    In this thesis we have focused our studies towards a better understanding of different processes involved in the protein secretion pathway that might act as bottlenecks for homologous and heterologous protein production. We have given particular attention to the molecular mechanisms of folding and q

  2. Moessbauer study of function of magnesium in iron oxide catalysts

    Institute of Scientific and Technical Information of China (English)

    YangJie-Xin; MaoLian-Sheng; 等

    1997-01-01

    Moessbauer spectroscopy has been utilized for studying the action of Mg element in iron oxide catalysts used for the dehydrogenation of ethylbenzene to sytrene.The experimental results show that the presence of opportune amount of Mg can enhance the stability and dispersion of catalysts,i.e.Mg is an sueful structure promoter in this kind of catalysts.

  3. From genome to function by studying eQTLs

    NARCIS (Netherlands)

    Westra, Harm-Jan; Franke, Lude

    2014-01-01

    Genome-wide association studies (GWASs) have shown a large number of genetic variants to be associated with complex diseases. The identification of the causal variant within an associated locus can sometimes be difficult because of the linkage disequilibrium between the associated variants and becau

  4. Study of liver function and expression of some detoxification genes ...

    African Journals Online (AJOL)

    Ahmad Ali Badr

    2015-10-19

    Oct 19, 2015 ... stress. Study of alteration of end organ markers and mRNA due to MTBE ... Results: Statistical analysis showed that in the MTBE treated groups, serum albumin ... Production and hosting by Elsevier B.V. on behalf of Ain Shams University. ... MTBE is rapidly and readily absorbed via inhalation and oral.

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

    Institute of Scientific and Technical Information of China (English)

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

    2016-01-01

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

  6. Monotonicity of a Key Function Arised in Studies of Nematic Liquid Crystal Polymers

    Directory of Open Access Journals (Sweden)

    Hongyun Wang

    2007-01-01

    Full Text Available We revisit a key function arised in studies of nematic liquid crystal polymers. Previously, it was conjectured that the function is strictly decreasing and the conjecture was numerically confirmed. Here we prove the conjecture analytically. More specifically, we write the derivative of the function into two parts and prove that each part is strictly negative.

  7. A Density Functional Study of Atomic Carbon Adsorption on δ-Pu(111)Surface

    Institute of Scientific and Technical Information of China (English)

    WEI Hong-Yuan; XIONG Xiao-Ling; SONG Hong-Tao; LUO Shun-Zhong

    2010-01-01

    @@ Adsorption of atomic carbon on δ-Pu(111)surface is investigated systematically using density functional theory with RPBE functional.The adsorption energies,adsorption structures,Mulliken population,work functions,layer and projected density of states are calculated in wide ranges of coverage,which have never been studied before as far as we know.

  8. Density functional theory study of proton transfer in carbonic anhydrase

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lidong; XIE Daiqian

    2005-01-01

    Proton transfer in carbonic anhydrase II has been studied at the B3LYP/6-31G(D) level. The active site model consists of the zinc ion, four histidine residues, two threonine residues, and three water molecules. Our calculations showed that the proton of the zinc-bound water molecule could be transferred to the nearest water molecule and an intermediate containing H3O+ is then formed. The intermediate is only 1.3 kJ·mol-1 above the reactant complex, whereas the barrier height for the proton transfer is about 8.1 kJ·mol-1.

  9. A (time-dependent) density functional theory study of the optoelectronic properties of bis-triisopropylsilylethynyl-functionalized acenes

    Energy Technology Data Exchange (ETDEWEB)

    Malloci, G., E-mail: giuliano.malloci@dsf.unica.it [Istituto Officina dei Materiali (CNR-IOM), Unità di Cagliari, Cittadella Universitaria, I-09042 Monserrato (Italy); Cappellini, G. [Istituto Officina dei Materiali (CNR-IOM), Unità di Cagliari, Cittadella Universitaria, I-09042 Monserrato (Italy); Dipartimento di Fisica, Università degli Studi di Cagliari, Cittadella Universitaria, I-09042 Monserrato (Italy); Mulas, G. [INAF-Osservatorio Astronomico di Cagliari, Strada 54, Località Poggio dei Pini, I-09012 Capoterra (Italy); Mattoni, A. [Istituto Officina dei Materiali (CNR-IOM), Unità di Cagliari, Cittadella Universitaria, I-09042 Monserrato (Italy)

    2013-09-30

    We report a comparative study of the optoelectronic properties of small acenes (benzene, anthracene, and pentacene) and their bis-triisopropylsilylethynyl (TIPS) functionalized counterparts. We computed the fundamental gap using density functional theory (DFT) in the framework of the ΔSCF scheme, and the optical absorption spectra by means of time-dependent DFT. Upon TIPS functionalization we observed a lowering of the ionization energy and a rise of the electron affinity; we consequently predict a systematic reduction of the fundamental electronic gap which decreases from ∼ 40% for benzene to ∼ 16% for pentacene. This trend is reflected in the computed optical absorption spectra: for all TIPS-molecules the onset of absorption is red-shifted as compared to their plain precursors. In the case of TIPS-pentacene, in particular, the computed spectrum agrees with the available experimental data. - Highlights: • We evaluate the effect of triisopropylsilylethynyl (TIPS)-substitution on acenes. • We compared the fundamental gap and the optical absorption as a function of size. • We found a general gap reduction following TIPS functionalization. • The gap reduction decreases at increasing size, from 40% for n = 1 to 16% for n = 5. • The onset of absorption is red-shifted as compared to TIPS precursors.

  10. Porosity and fractal study of functionalized carbon nanofibers: Effects of the functionalization degree on hydrogen storage capacity

    Science.gov (United States)

    Galindo-Hernández, Félix; Portales, Benjamín; Domínguez, José M.; Angeles-Beltrán, Deyanira

    2014-12-01

    Carbon nanofibers are produced by siliceous SBA-15 type materials and the casting method. The nanofibers are functionalized by HNO3 attack in aqueous phase under microwave radiation. N2 sorption data are treated by Non-Local Density Functional Theory and Quenched Solid Density Functional Theory to determine advanced adsorption among other textural properties. The functionalization degree of carbon nanofibers and their hydrogen storage capacity are mainly investigated by FTIR spect