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Sample records for acid spin labels

  1. Convenient biosynthetic preparation of isomeric spin-labelled radioactive phosphatidic acids

    Energy Technology Data Exchange (ETDEWEB)

    Stuhne, L.; Stanacev, N.Z. (Toronto Univ., Ontario (Canada). Dept. of Clinical Biochemistry)

    1982-11-01

    A convenient method for the enzymatic preparation of sn-3-(2-/sup 3/H)phosphatidic acids carrying also 5-, 12-, or 16-nitroxide stearic acids, from sn-3-(2-/sup 3/H) glycerophosphate and isolated guinea pig liver microsomes, is described in detail. The procedure allows a simultaneous preparation of three spin-labelled sn-3-(2-/sup 3/H)phosphatidic acids of yields 3-3.5..mu..mol of each compound which is >99% pure in respect to the radioactivity and which contains 25 mol% of spin-labelled fatty acids. These phosphatidic acids were approximately equally distributed between the primary and the secondary hydroxyl when 12- or 16-nitroxide stearic acids were used or predominantly (75%) associated with the secondary hydroxyl of sn-3-(2-/sup 3/H)phosphatidic acid when 5-nitroxide stearic acid was present in the incubation mixture.

  2. Spin labels. Applications in biology

    International Nuclear Information System (INIS)

    Frangopol, T.P.; Frangopol, M.; Ionescu, S.M.; Pop, I.V.; Benga, G.

    1980-11-01

    The main applications of spin labels in the study of biomembranes, enzymes, nucleic acids, in pharmacology, spin immunoassay are reviewed along with the fundamentals of the spin label method. 137 references. (author)

  3. Intra-albumin migration of bound fatty acid probed by spin label ESR

    International Nuclear Information System (INIS)

    Gurachevsky, Andrey; Shimanovitch, Ekaterina; Gurachevskaya, Tatjana; Muravsky, Vladimir

    2007-01-01

    Conventional ESR spectra of 16-doxyl-stearic acid bound to bovine and human serum albumin were recorded at different temperatures in order to investigate the status of spin-labeled fatty acid in the interior of the protein globule. A computer spectrum simulation of measured spectra, performed by non-linear least-squares fits, clearly showed two components corresponding to strongly and weakly immobilized fatty acid molecules. The two-component model was verified on spectra measured at different pH. Thermodynamic parameters of the spin probe exchange between two spin probe states were analyzed. It was concluded that at physiological conditions, fatty acid molecules permanently migrate in the globule interior between the specific binding sites and a space among albumin domains

  4. Spin labeled amino acid nitrosourea derivatives--synthesis and antitumour activity.

    Science.gov (United States)

    Zheleva, A; Raikov, Z; Ilarionova, M; Todorov, D

    1995-01-01

    The synthesis of three spin labeled derivatives of N-[N'-(chloroethyl)-N'-nitrosocarbamoyl] amino acids is reported. The new nitrosoureas are obtained by condensation of the corresponding N-[N'-(2-chloroethyl)-N'-nitrosocarbamoyl] amino acid with 2,2,6,6-tetramethyl-1-oxyl-4-aminopiperidine using dicyclohexylcarbodiimide. Their chemical structures are confirmed by elemental analysis, IR, MS, and EPR spectroscopy. All newly synthesized compounds showed high antitumour activity against the lymphoid leukemia L1210 in BDF1 mice.

  5. Stearic acid spin labels in lipid bilayers :  insight through atomistic simulations

    NARCIS (Netherlands)

    Stimson, L.M.; Dong, L.; Karttunen, M.E.J.; Wisniewska, A.; Dutka, M.; Róg, T.

    2007-01-01

    Spin-labeled stearic acid species are commonly used for electron paramagnetic resonance (EPR) studies of cell membranes to investigate phase transitions, fluidity, and other physical properties. In this paper, we use large-scale molecular dynamics simulations to investigate the position and behavior

  6. Site-Directed Spin-Labeling of Nucleic Acids by Click Chemistry. Detection of Abasic Sites in Duplex DNA by EPR Spectroscopy

    DEFF Research Database (Denmark)

    Sigurdsson, Snorri; Vogel, Stefan; Shelke, Sandip

    2010-01-01

    and the nitroxide spin label. The spin label was used to detect, for the first time, abasic sites in duplex DNA by X-band CW-EPR spectroscopy and give information about other structural deformations as well as local conformational changes in DNA. For example, reduced mobility of the spin label in a mismatched pair...... label out of the duplex and toward the solution. Thus, reposition of the spin label, when acting as a mercury(II)-controlled mechanical lever, can be readily detected by EPR spectroscopy. The ease of incorporation and properties of the new spin label make it attractive for EPR studies of nucleic acids...

  7. RosettaEPR: rotamer library for spin label structure and dynamics.

    Directory of Open Access Journals (Sweden)

    Nathan S Alexander

    Full Text Available An increasingly used parameter in structural biology is the measurement of distances between spin labels bound to a protein. One limitation to these measurements is the unknown position of the spin label relative to the protein backbone. To overcome this drawback, we introduce a rotamer library of the methanethiosulfonate spin label (MTSSL into the protein modeling program Rosetta. Spin label rotamers were derived from conformations observed in crystal structures of spin labeled T4 lysozyme and previously published molecular dynamics simulations. Rosetta's ability to accurately recover spin label conformations and EPR measured distance distributions was evaluated against 19 experimentally determined MTSSL labeled structures of T4 lysozyme and the membrane protein LeuT and 73 distance distributions from T4 lysozyme and the membrane protein MsbA. For a site in the core of T4 lysozyme, the correct spin label conformation (Χ1 and Χ2 is recovered in 99.8% of trials. In surface positions 53% of the trajectories agree with crystallized conformations in Χ1 and Χ2. This level of recovery is on par with Rosetta performance for the 20 natural amino acids. In addition, Rosetta predicts the distance between two spin labels with a mean error of 4.4 Å. The width of the experimental distance distribution, which reflects the flexibility of the two spin labels, is predicted with a mean error of 1.3 Å. RosettaEPR makes full-atom spin label modeling available to a wide scientific community in conjunction with the powerful suite of modeling methods within Rosetta.

  8. A spin labelling study of immunomodulating peptidoglycan monomer and adamantyltripeptides entrapped into liposomes.

    Science.gov (United States)

    Frkanec, Ruza; Noethig-Laslo, Vesna; Vranesić, Branka; Mirosavljević, Krunoslav; Tomasić, Jelka

    2003-04-01

    The interaction of immunostimulating compounds, the peptidoglycan monomer (PGM) and structurally related adamantyltripeptides (AdTP1 and AdTP2), respectively, with phospholipids in liposomal bilayers were investigated by electron paramagnetic resonance spectroscopy. (1). The fatty acids bearing the nitroxide spin label at different positions along the acyl chain were used to investigate the interaction of tested compounds with negatively charged multilamellar liposomes. Electron spin resonance (ESR) spectra were studied at 290 and 310 K. The entrapment of the adamantyltripeptides affected the motional properties of all spin labelled lipids, while the entrapment of PGM had no effect. (2). Spin labelled PGM was prepared and the novel compound bearing the spin label attached via the amino group of diaminopimelic acid was chromatographically purified and chemically characterized. The rotational correlation time of the spin labelled molecule dissolved in buffer at pH 7.4 was studied as a function of temperature. The conformational change was observed above 300 K. The same effect was observed with the spin labelled PGM incorporated into liposomes. Such effect was not observed when the spin labelled PGM was studied at alkaline pH, probably due to the hydrolysis of PGM molecule. The study of possible interaction with liposomal membrane is relevant to the use of tested compounds incorporated into liposomes, as adjuvants in vivo.

  9. Nuclear spin-lattice relaxation in nitroxide spin-label EPR.

    Science.gov (United States)

    Marsh, Derek

    2016-11-01

    Nuclear relaxation is a sensitive monitor of rotational dynamics in spin-label EPR. It also contributes competing saturation transfer pathways in T 1 -exchange spectroscopy, and the determination of paramagnetic relaxation enhancement in site-directed spin labelling. A survey shows that the definition of nitrogen nuclear relaxation rate W n commonly used in the CW-EPR literature for 14 N-nitroxyl spin labels is inconsistent with that currently adopted in time-resolved EPR measurements of saturation recovery. Redefinition of the normalised 14 N spin-lattice relaxation rate, b=W n /(2W e ), preserves the expressions used for CW-EPR, whilst rendering them consistent with expressions for saturation recovery rates in pulsed EPR. Furthermore, values routinely quoted for nuclear relaxation times that are deduced from EPR spectral diffusion rates in 14 N-nitroxyl spin labels do not accord with conventional analysis of spin-lattice relaxation in this three-level system. Expressions for CW-saturation EPR with the revised definitions are summarised. Data on nitrogen nuclear spin-lattice relaxation times are compiled according to the three-level scheme for 14 N-relaxation: T 1 n =1/W n . Results are compared and contrasted with those for the two-level 15 N-nitroxide system. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. EPR spin probe and spin label studies of some low molecular and polymer micelles

    Science.gov (United States)

    Wasserman, A. M.; Kasaikin, V. A.; Timofeev, V. P.

    1998-12-01

    The rotational mobility of spin probes of different shape and size in low molecular and polymer micelles has been studied. Several probes having nitroxide fragment localized either in the vicinity of micelle interface or in the hydrocarbon core have been used. Upon increasing the number of carbon atoms in hydrocarbon chain of detergent from 7 to 13 (sodium alkyl sulfate micelles) or from 12 to 16 (alkyltrimethylammonium bromide micelles) the rotational mobility of spin probes is decreased by the factor 1.5-2.0. The spin probe rotational mobility in polymer micelles (the complexes of alkyltrimethylammonium bromides and polymethacrylic or polyacrylic acids) is less than mobility in free micelles of the same surfactants. The study of EPR-spectra of spin labeled polymethacrylic acid (PMA) indicated that formation of water soluble complexes of polymer and alkyltrimethylammonium bromides in alkaline solutions (pH 9) does not affect the polymer segmental mobility. On the other hand, the polymer complexes formation in slightly acidic water solution (pH 6) breaks down the compact PMA conformation, thus increasing the polymer segmental mobility. Possible structures of polymer micelles are discussed.

  11. Spin-labelling study of interactions of ovalbumin with multilamellar liposomes and specific anti-ovalbumin antibodies.

    Science.gov (United States)

    Brgles, Marija; Mirosavljević, Krunoslav; Noethig-Laslo, Vesna; Frkanec, Ruza; Tomasić, Jelka

    2007-03-10

    Ovalbumin (OVA) has been used continuously as the model antigen in numerous studies of immune reactions and antigen processing, very often encapsulated into liposomes. The purpose of this work was to study the possible interactions of spin-labelled OVA and lipids in liposomal membranes using electron spin resonance (ESR) spectroscopy. OVA was covalently spin-labelled with 4-maleimido-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO-maleimide), characterized and encapsulated into multilamellar, negatively charged liposomes. ESR spectra of this liposomal preparation gave evidence for the interaction of OVA with the lipid bilayers. Such an interaction was also evidenced by the ESR spectra of liposomal preparation containing OVA, where liposomes were spin-labelled with n-doxyl stearic acids. The spin-labelled OVA retains its property to bind specific anti-OVA antibodies, as shown by ESR spectroscopy, but also in ELISA for specific anti-OVA IgG.

  12. Cross relaxation in nitroxide spin labels

    DEFF Research Database (Denmark)

    Marsh, Derek

    2016-01-01

    Cross relaxation, and mI-dependence of the intrinsic electron spin-lattice relaxation rate We, are incorporated explicitly into the rate equations for the electron-spin population differences that govern the saturation behaviour of 14N- and 15N-nitroxide spin labels. Both prove important in spin......-label EPR and ELDOR, particularly for saturation recovery studies. Neither for saturation recovery, nor for CW-saturation EPR and CW-ELDOR, can cross relaxation be described simply by increasing the value of We, the intrinsic spin-lattice relaxation rate. Independence of the saturation recovery rates from...... the hyperfine line pumped or observed follows directly from solution of the rate equations including cross relaxation, even when the intrinsic spin-lattice relaxation rate We is mI-dependent....

  13. Spin labelled nitrosoureas and triazenes and their non-labelled clinically used analogues--a comparative study on their physicochemical properties and antimelanomic effects.

    Science.gov (United States)

    Zheleva, A M; Gadjeva, V G

    2001-01-16

    Physicochemical properties, such as half life time (tau0.5), alkylating and carbamoylating activity and in vivo antimelanomic effects against B16 melanoma of spin labeled (containing nitroxyl free radical moiety) amino acid nitrosoureas, synthesized in our laboratory, have been studied and compared to those of the antitumor drug N'-cyclohexyl-N-(2-chloroethyl)-N-nitrosourea (lomustine, CCNU). We have shown that the introduction of amino acid moieties and the replacement of cyclohexylamine with nitroxyl moiety leads to a faster decomposition, higher alkylating, lower carbamoylating activity, better antimelanomic activity and lower general toxicity, when compared to those of CCNU. It was also established that spin labeled triazenes, previously synthesized by us, were more stable in phosphate saline than their nonlabeled analogue, 5-(3,3-dimethyltriazene-1-yl)-imidazole-4-carboxamide (dacarbazine, DTIC). A higher cytotoxicity to B16 melanoma cells than to YAC-1 and lymphocytes was demonstrated for all spin labeled triazenes, in comparison with DTIC. An assumption has been made to explain the lower general toxicity of the spin labeled nitrosoureas compared to that of CCNU. Based on the results presented, we accept that a new trend for synthesis of more selective and less toxic nitrosourea and triazene derivatives as potential antimelanomic drugs might be developed.

  14. Conformational change of spin labelled myoglobin

    International Nuclear Information System (INIS)

    Wajnberg, E.; Ribeiro, P.C.; Nascimento, O.R.; Bemski, G.

    1978-01-01

    A conformational change of spin labelled myoglobin have been followed by measuring the spin label's (isothiocyanate) correlation time for temperatures between 18 0 C and 44 0 C. The correlation time was calculated from Electrom Paramagnetic Ressonance Spectra using the components of the espectroscopic and hiperfine tensors obtained by fitting the powder spectra using Lefebvre and Maruani's program- [pt

  15. Insight into the labeling mechanism of acceleration selective arterial spin labeling

    DEFF Research Database (Denmark)

    Schmid, Sophie; Petersen, Esben T; Van Osch, Matthias J P

    2017-01-01

    OBJECTIVES: Acceleration selective arterial spin labeling (AccASL) is a spatially non-selective labeling technique, used in traditional ASL methods, which labels spins based on their flow acceleration rather than spatial localization. The exact origin of the AccASL signal within the vasculature......-ASL, combined AccASL and VS-ASL signal, and signal from one module with crushing from the other. RESULTS: The label created with AccASL has an overlap of approximately 50% in the vascular region with VS-ASL, but also originates from smaller vessels closer to the capillaries. CONCLUSION: AccASL is able to label...

  16. Site-specific labeling of proteins with NMR-active unnatural amino acids

    International Nuclear Information System (INIS)

    Jones, David H.; Cellitti, Susan E.; Hao Xueshi; Zhang Qiong; Jahnz, Michael; Summerer, Daniel; Schultz, Peter G.; Uno, Tetsuo; Geierstanger, Bernhard H.

    2010-01-01

    A large number of amino acids other than the canonical amino acids can now be easily incorporated in vivo into proteins at genetically encoded positions. The technology requires an orthogonal tRNA/aminoacyl-tRNA synthetase pair specific for the unnatural amino acid that is added to the media while a TAG amber or frame shift codon specifies the incorporation site in the protein to be studied. These unnatural amino acids can be isotopically labeled and provide unique opportunities for site-specific labeling of proteins for NMR studies. In this perspective, we discuss these opportunities including new photocaged unnatural amino acids, outline usage of metal chelating and spin-labeled unnatural amino acids and expand the approach to in-cell NMR experiments.

  17. Nuclear spin-lattice relaxation in nitroxide spin-label EPR

    DEFF Research Database (Denmark)

    Marsh, Derek

    2016-01-01

    that the definition of nitrogen nuclear relaxation rate Wn commonly used in the CW-EPR literature for 14N-nitroxyl spin labels is inconsistent with that currently adopted in time-resolved EPR measurements of saturation recovery. Redefinition of the normalised 14N spin-lattice relaxation rate, b = Wn/(2We), preserves...... of spin-lattice relaxation in this three-level system. Expressions for CW-saturation EPR with the revised definitions are summarised. Data on nitrogen nuclear spin-lattice relaxation times are compiled according to the three-level scheme for 14N-relaxation: T1 n = 1/Wn. Results are compared and contrasted...

  18. New Developments in Spin Labels for Pulsed Dipolar EPR

    Directory of Open Access Journals (Sweden)

    Alistair J. Fielding

    2014-10-01

    Full Text Available Spin labelling is a chemical technique that enables the integration of a molecule containing an unpaired electron into another framework for study. Given the need to understand the structure, dynamics, and conformational changes of biomacromolecules, spin labelling provides a relatively non-intrusive technique and has certain advantages over X-ray crystallography; which requires high quality crystals. The technique relies on the design of binding probes that target a functional group, for example, the thiol group of a cysteine residue within a protein. The unpaired electron is typically supplied through a nitroxide radical and sterically shielded to preserve stability. Pulsed electron paramagnetic resonance (EPR techniques allow small magnetic couplings to be measured (e.g., <50 MHz providing information on single label probes or the dipolar coupling between multiple labels. In particular, distances between spin labels pairs can be derived which has led to many protein/enzymes and nucleotides being studied. Here, we summarise recent examples of spin labels used for pulse EPR that serve to illustrate the contribution of chemistry to advancing discoveries in this field.

  19. Spin labelling of human erythrocytes with nitroxide radicals

    International Nuclear Information System (INIS)

    Chagalj, C.; DePaoli, T.C.P.; Hager, A.A.; Palaoro, L.A.; Rubin de Celis, E.; Farach, H.A.; Poole, C.P. jr

    1984-01-01

    Human erythrocytes were labelled with nitroxide, the spin label SYNVAR 101, under various experimantal conditions. A study was made of the influence of antireductants on the labelling efficiency and the kinetics of the radical decay during the labelling process

  20. Electron Spin Resonance Studies of Carbonic Anhydrase: Transition Metal Ions and Spin-Labeled Sulfonamides*

    Science.gov (United States)

    Taylor, June S.; Mushak, Paul; Coleman, Joseph E.

    1970-01-01

    Electron spin resonance (esr) spectra of Cu(II) and Co(II) carbonic anhydrase, and a spin-labeled sulfonamide complex of the Zn(II) enzyme, are reported. The coordination geometry of Cu(II) bound in the enzyme appears to have approximately axial symmetry. Esr spectra of enzyme complexes with metal-binding anions also show axial symmetry and greater covalency, in the order ethoxzolamide cyanide complex suggests the presence of two, and probably three, equivalent nitrogen ligands from the protein. Esr spectra of the Co(II) enzyme and its complexes show two types of Co(II) environment, one typical of the native enzyme and the 1:1 CN- complex, and one typical of a 2:1 CN- complex. Co(II) in the 2:1 complex appears to be low-spin and probably has a coordination number of 5. Binding of a spin-labeled sulfonamide to the active center immobilizes the free radical. The similarity of the esr spectra of spin-labeled Zn(II) and Co(II) carbonic anhydrases suggests that the conformation at the active center is similar in the two metal derivatives. PMID:4320976

  1. Kinetics of rapid covalent bond formation of aniline with humic acid: ESR investigations with nitroxide spin labels

    Science.gov (United States)

    Glinka, Kevin; Matthies, Michael; Theiling, Marius; Hideg, Kalman; Steinhoff, Heinz-Jürgen

    2016-04-01

    Sulfonamide antibiotics used in livestock farming are distributed to farmland by application of slurry as fertilizer. Previous work suggests rapid covalent binding of the aniline moiety to humic acids found in soil. In the current work, kinetics of this binding were measured in X-band EPR spectroscopy by incubating Leonardite humic acid (LHA) with a paramagnetic aniline spin label (anilino-NO (2,5,5-Trimethyl-2-(3-aminophenyl)pyrrolidin-1-oxyl)). Binding was detected by a pronounced broadening of the spectral lines after incubation of LHA with anilino-NO. The time evolution of the amplitude of this feature was used for determining the reaction kinetics. Single- and double-exponential models were fitted to the data obtained for modelling one or two first-order reactions. Reaction rates of 0.16 min-1 and 0.012 min-1, were found respectively. Addition of laccase peroxidase did not change the kinetics but significantly enhanced the reacting fraction of anilino-NO. This EPR-based method provides a technically simple and effective method for following rapid binding processes of a xenobiotic substance to humic acids.

  2. Mobility of TOAC spin-labelled peptides binding to the Src SH3 domain studied by paramagnetic NMR

    Energy Technology Data Exchange (ETDEWEB)

    Lindfors, Hanna E. [Leiden University, Leiden Institute of Chemistry, Gorlaeus Laboratories (Netherlands); Koning, Peter E. de; Wouter Drijfhout, Jan [Leiden University Medical Centre, Department of Immunohematology and Blood Transfusion (Netherlands); Venezia, Brigida; Ubbink, Marcellus [Leiden University, Leiden Institute of Chemistry, Gorlaeus Laboratories (Netherlands)], E-mail: m.ubbink@chem.leidenuniv.nl

    2008-07-15

    Paramagnetic relaxation enhancement provides a tool for studying the dynamics as well as the structure of macromolecular complexes. The application of side-chain coupled spin-labels is limited by the mobility of the free radical. The cyclic, rigid amino acid spin-label TOAC (2,2,6,6-Tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid), which can be incorporated straightforwardly by peptide synthesis, provides an attractive alternative. In this study, TOAC was incorporated into a peptide derived from focal adhesion kinase (FAK), and the interaction of the peptide with the Src homology 3 (SH3) domain of Src kinase was studied, using paramagnetic NMR. Placing TOAC within the binding motif of the peptide has a considerable effect on the peptide-protein binding, lowering the affinity substantially. When the TOAC is positioned just outside the binding motif, the binding constant remains nearly unaffected. Although the SH3 domain binds weakly and transiently to proline-rich peptides from FAK, the interaction is not very dynamic and the relative position of the spin-label to the protein is well-defined. It is concluded that TOAC can be used to generate reliable paramagnetic NMR restraints.

  3. Mobility of TOAC spin-labelled peptides binding to the Src SH3 domain studied by paramagnetic NMR

    International Nuclear Information System (INIS)

    Lindfors, Hanna E.; Koning, Peter E. de; Wouter Drijfhout, Jan; Venezia, Brigida; Ubbink, Marcellus

    2008-01-01

    Paramagnetic relaxation enhancement provides a tool for studying the dynamics as well as the structure of macromolecular complexes. The application of side-chain coupled spin-labels is limited by the mobility of the free radical. The cyclic, rigid amino acid spin-label TOAC (2,2,6,6-Tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid), which can be incorporated straightforwardly by peptide synthesis, provides an attractive alternative. In this study, TOAC was incorporated into a peptide derived from focal adhesion kinase (FAK), and the interaction of the peptide with the Src homology 3 (SH3) domain of Src kinase was studied, using paramagnetic NMR. Placing TOAC within the binding motif of the peptide has a considerable effect on the peptide-protein binding, lowering the affinity substantially. When the TOAC is positioned just outside the binding motif, the binding constant remains nearly unaffected. Although the SH3 domain binds weakly and transiently to proline-rich peptides from FAK, the interaction is not very dynamic and the relative position of the spin-label to the protein is well-defined. It is concluded that TOAC can be used to generate reliable paramagnetic NMR restraints

  4. Temperature-induced changes in lecithin model membranes detected by novel covalent spin-labelled phospholipids.

    Science.gov (United States)

    Stuhne-Sekalec, L; Stanacev, N Z

    1977-02-01

    Several spin-labelled phospholipids carrying covalently bound 5-doxylstearic acid (2-(3-carboxydecyl)-2-hexyl-4,4-dimethyl-3-oxazolidinoxyl) were intercalated in liposomes of saturated and unsaturated lecithins. Temperature-induced changes of these liposomes, detected by the spin-labelled phospholipids, were found to be in agreement with the previously described transitions of hydrocarbon chains of host lecithins detected by different probes and different techniques, establishing that spin-labelled phosopholipids are sensitive probes for the detection of temperature-induced changes in lecithin model membranes. In addition to the detection of already-known transitions in lecithin liposomes, the coexistence of two distinctly different enviroments was observed above the characteristic transition temperature. This phenomenon was tentatively attributed to the influence of the lecithin polar group on the fluidity of fatty acyl chains near the polar group. Combined with other results from the literature, the coexistence of two environments could be associated with the coexistence of two conformational isomers of lecithin, differing in the orientation of the polar head group with respect to the plane of bilayer. These findings have been discussed in view of the present state of knowledge regarding temperature-induced changes in model membranes.

  5. Communication: Orientational self-ordering of spin-labeled cholesterol analogs in lipid bilayers in diluted conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kardash, Maria E.; Dzuba, Sergei A., E-mail: dzuba@kinetics.nsc.ru [Voevodsky Institute of Chemical Kinetics and Combustion, 630090 Novosibirsk, Russia, and Novosibirsk State University, 630090 Novosibirsk (Russian Federation)

    2014-12-07

    Lipid-cholesterol interactions are responsible for different properties of biological membranes including those determining formation in the membrane of spatial inhomogeneities (lipid rafts). To get new information on these interactions, electron spin echo (ESE) spectroscopy, which is a pulsed version of electron paramagnetic resonance (EPR), was applied to study 3β-doxyl-5α-cholestane (DCh), a spin-labeled analog of cholesterol, in phospholipid bilayer consisted of equimolecular mixture of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and 1,2-dioleoyl-sn-glycero-3-phosphocholine. DCh concentration in the bilayer was between 0.1 mol.% and 4 mol.%. For comparison, a reference system containing a spin-labeled 5-doxyl-stearic acid (5-DSA) instead of DCh was studied as well. The effects of “instantaneous diffusion” in ESE decay and in echo-detected (ED) EPR spectra were explored for both systems. The reference system showed good agreement with the theoretical prediction for the model of spin labels of randomly distributed orientations, but the DCh system demonstrated remarkably smaller effects. The results were explained by assuming that neighboring DCh molecules are oriented in a correlative way. However, this correlation does not imply the formation of clusters of cholesterol molecules, because conventional continuous wave EPR spectra did not show the typical broadening due to aggregation of spin labels and the observed ESE decay was not faster than in the reference system. So the obtained data evidence that cholesterol molecules at low concentrations in biological membranes can interact via large distances of several nanometers which results in their orientational self-ordering.

  6. Peptide-membrane Interactions by Spin-labeling EPR

    Science.gov (United States)

    Smirnova, Tatyana I.; Smirnov, Alex I.

    2016-01-01

    Site-directed spin labeling (SDSL) in combination with Electron Paramagnetic Resonance (EPR) spectroscopy is a well-established method that has recently grown in popularity as an experimental technique, with multiple applications in protein and peptide science. The growth is driven by development of labeling strategies, as well as by considerable technical advances in the field, that are paralleled by an increased availability of EPR instrumentation. While the method requires an introduction of a paramagnetic probe at a well-defined position in a peptide sequence, it has been shown to be minimally destructive to the peptide structure and energetics of the peptide-membrane interactions. In this chapter, we describe basic approaches for using SDSL EPR spectroscopy to study interactions between small peptides and biological membranes or membrane mimetic systems. We focus on experimental approaches to quantify peptide-membrane binding, topology of bound peptides, and characterize peptide aggregation. Sample preparation protocols including spin-labeling methods and preparation of membrane mimetic systems are also described. PMID:26477253

  7. Spin-labeled 1-alkyl-1-nitrosourea synergists of antitumor antibiotics.

    Science.gov (United States)

    Gadjeva, V; Koldamova, R

    2001-01-01

    A new method for synthesis of four spin-labeled structural analogues of the antitumor drug 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), using ethyl nitrite for nitrosation of the intermediate spin-labeled ureas has been described. In vitro synergistic effects of 1-ethyl-3-[4-(2,2,6,6-tetramethylpiperidine-1-oxyl)]-1-nitrosourea (3b) on the cytotoxicity of bleomycin and farmorubicin were found in human lymphoid leukemia tumor cells. We measured the tissue distribution of 3b in organ homogenates of C57BL mice by an electron paramagnetic resonance method. The spin-labeled nitrosourea was mainly localized in the lungs. Our results strongly support the development and validation of a new approach for synthesis of less toxic nitrosourea derivatives as potential synergists of antitumor drugs.

  8. Conformational changes of plasma fibronectin detected upon adsorption to solid substrates: A spin-label study

    International Nuclear Information System (INIS)

    Narasimhan, C.; Lai, Chingsan

    1989-01-01

    Changes in local environment of the free sulfhydryl groups in plasma fibronectin upon adsorption of the protein to polystyrene beads have been examined by electron spin resonance (ESR) spin-label spectroscopy. The two free sulfhydryl groups per subunit of plasma fibronectin were modified chemically with an [ 15 N, 2 H]maleimide spin-label. For soluble fibronectin, both free sulfhydryl groups shown to be in confined environments as evidenced from the labeled protein exhibiting a strongly immobilized ESR spectrum as described previously using [ 14 N, 1 H]maleimide spin-labels. When the labeled protein was adsorbed to the beads, half of the strongly immobilized component was found to convert into a weakly immobilized component, a result indicating that one of the two labeled sites becomes exposed and exhibits a fast tumbling motion. Experiments conducted using various spin-labeled fibronectin fragments suggest that the newly exposed labeled site is located between the DNA-binding and the cell-binding regions of the molecule. The data obtained indicate that, upon adsorption to polystyrene beads, plasma fibronectin undergoes a conformational change through which the buried free sulfhydryl group near the cell-binding region of the molecule is exposed. This observation may have important implications regarding the expression of cell adhesive properties of the fibronectin molecule

  9. Technological advances in site-directed spin labeling of proteins.

    Science.gov (United States)

    Hubbell, Wayne L; López, Carlos J; Altenbach, Christian; Yang, Zhongyu

    2013-10-01

    Molecular flexibility over a wide time range is of central importance to the function of many proteins, both soluble and membrane. Revealing the modes of flexibility, their amplitudes, and time scales under physiological conditions is the challenge for spectroscopic methods, one of which is site-directed spin labeling EPR (SDSL-EPR). Here we provide an overview of some recent technological advances in SDSL-EPR related to investigation of structure, structural heterogeneity, and dynamics of proteins. These include new classes of spin labels, advances in measurement of long range distances and distance distributions, methods for identifying backbone and conformational fluctuations, and new strategies for determining the kinetics of protein motion. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. The effects of general anesthetics on ESR spectra of spin labels in phosphatidylcholine vesicles containing purified Na,K-ATPase or microsomal protein

    Energy Technology Data Exchange (ETDEWEB)

    Shibuya, Makiko, E-mail: shibu@den.hokudai.ac.jp [Department of Dental Anesthesiology, Graduate School of Dental Medicine, Hokkaido University (Japan); Hiraoki, Toshifumi [Division of Applied Physics, Graduate School of Engineering, Hokkaido University (Japan); Kimura, Kunie; Fukushima, Kazuaki [Department of Dental Anesthesiology, Graduate School of Dental Medicine, Hokkaido University (Japan); Suzuki, Kuniaki [Department of Molecular Cell Pharmacology, Graduate School of Dental Medicine, Hokkaido University (Japan)

    2012-12-01

    Highlights: Black-Right-Pointing-Pointer We studied the effects of general anesthetics on liposome using ESR spectra. Black-Right-Pointing-Pointer Two spin labels, 5-DSA and 16-DSA, were located in different position in liposome. Black-Right-Pointing-Pointer Anesthetics did not change the environment around the spin labels in the liposome. Black-Right-Pointing-Pointer Anesthetics remained on the surface of the lipid bilayer of liposome. Black-Right-Pointing-Pointer Proteins in the liposome did not change the effects of anesthetics on liposome. - Abstract: We investigated the effects of general anesthetics on liposome containing spin labels, 5-doxyl stearic acid (5-DSA) and 16-doxyl stearic acid (16-DSA), and purified Na,K-ATPase or membrane protein of microsome using an electron spin resonance (ESR) spectroscopy. The spectra of 16-DSA in liposomes with both proteins showed three sharp signals compared with 5-DSA. The difference in the order parameter S value of 5-DSA and 16-DSA suggested that the nitroxide radical location of 5-DSA and 16-DSA were different in the membrane bilayer. The results were almost the same as those obtained in liposomes without proteins. The addition of sevoflurane, isoflurane, halothane, ether, ethanol and propofol increased the intensity of the signals, but the clinical concentrations of anesthetics did not significantly alter the S and {tau} values, which are indices of the fluidity of the membrane. These results suggest that anesthetics remain on the surface of the lipid bilayer and do not act on both the inside hydrophobic area and the relatively hydrophilic area near the surface. These results and others also suggest that the existence of Na,K-ATPase and microsomal proteins did not affect the environment around the spin labels in the liposome and the effects of anesthetics on liposome as a model membrane.

  11. Measurement of brain perfusion in newborns: Pulsed arterial spin labeling (PASL) versus pseudo-continuous arterial spin labeling (pCASL)

    Science.gov (United States)

    Boudes, Elodie; Gilbert, Guillaume; Leppert, Ilana Ruth; Tan, Xianming; Pike, G. Bruce; Saint-Martin, Christine; Wintermark, Pia

    2014-01-01

    Background Arterial spin labeling (ASL) perfusion-weighted imaging (PWI) by magnetic resonance imaging (MRI) has been shown to be useful for identifying asphyxiated newborns at risk of developing brain injury, whether or not therapeutic hypothermia was administered. However, this technique has been only rarely used in newborns until now, because of the challenges to obtain sufficient signal-to-noise ratio (SNR) and spatial resolution in newborns. Objective To compare two methods of ASL-PWI (i.e., single inversion-time pulsed arterial spin labeling [single TI PASL], and pseudo-continuous arterial spin labeling [pCASL]) to assess brain perfusion in asphyxiated newborns treated with therapeutic hypothermia and in healthy newborns. Design/methods We conducted a prospective cohort study of term asphyxiated newborns meeting the criteria for therapeutic hypothermia; four additional healthy term newborns were also included as controls. Each of the enrolled newborns was scanned at least once during the first month of life. Each MRI scan included conventional anatomical imaging, as well as PASL and pCASL PWI-MRI. Control and labeled images were registered separately to reduce the effect of motion artifacts. For each scan, the axial slice at the level of the basal ganglia was used for comparisons. Each scan was scored for its image quality. Quantification of whole-slice cerebral blood flow (CBF) was done afterwards using previously described formulas. Results A total number of 61 concomitant PASL and pCASL scans were obtained in nineteen asphyxiated newborns treated with therapeutic hypothermia and four healthy newborns. After discarding the scans with very poor image quality, 75% (46/61) remained for comparison between the two ASL methods. pCASL images presented a significantly superior image quality score compared to PASL images (p newborns. However, pCASL might be a better choice over PASL in newborns, as pCASL perfusion maps had a superior image quality that allowed a

  12. Toward the fourth dimension of membrane protein structure: insight into dynamics from spin-labeling EPR spectroscopy.

    Science.gov (United States)

    McHaourab, Hassane S; Steed, P Ryan; Kazmier, Kelli

    2011-11-09

    Trapping membrane proteins in the confines of a crystal lattice obscures dynamic modes essential for interconversion between multiple conformations in the functional cycle. Moreover, lattice forces could conspire with detergent solubilization to stabilize a minor conformer in an ensemble thus confounding mechanistic interpretation. Spin labeling in conjunction with electron paramagnetic resonance (EPR) spectroscopy offers an exquisite window into membrane protein dynamics in the native-like environment of a lipid bilayer. Systematic application of spin labeling and EPR identifies sequence-specific secondary structures, defines their topology and their packing in the tertiary fold. Long range distance measurements (60 Å-80 Å) between pairs of spin labels enable quantitative analysis of equilibrium dynamics and triggered conformational changes. This review highlights the contribution of spin labeling to bridging structure and mechanism. Efforts to develop methods for determining structures from EPR restraints and to increase sensitivity and throughput promise to expand spin labeling applications in membrane protein structural biology. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Spin-locking and cross-polarization under magic-angle spinning of uniformly labeled solids.

    Science.gov (United States)

    Hung, Ivan; Gan, Zhehong

    2015-07-01

    Spin-locking and cross-polarization under magic-angle spinning are investigated for uniformly (13)C and (15)N labeled solids. In particular, the interferences from chemical shift anisotropy, and (1)H heteronuclear and (13)C homonuclear dipolar couplings are identified. The physical origin of these interferences provides guidelines for selecting the best (13)C and (15)N polarization transfer rf fields. Optimal settings for both the zero- and double-quantum cross-polarization transfer mechanisms are recommended. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. On the search for new anticancer drugs 14: the plasma pharmacokinetics and tissue distribution of spin-labeled thio-TEPA (SL-O-TT).

    Science.gov (United States)

    Gutierrez, P L; Cohen, B E; Sosnovsky, G; Davis, T A; Egorin, M J

    1985-01-01

    We defined the plasma and tissue concentrations and pharmacokinetics of SL-O-TT, a spin-labeled analog of thio-TEPA, in 35-44-g male Swiss Webster mice that had received spin-labeled thio-TEPA at a dosage of 10 mg/kg. Concentrations of spin-labeled thio-TEPA in ethyl acetate extracts of tissue and plasma were determined by gas-liquid chromatography and electron spin resonance spectroscopy. Plasma concentrations of spin-labeled thio-TEPA declined in a biexponential fashion that was well described by the equation: Ct = 21.5e-0.276t + 2.30e-0.026t indicating a half-life alpha of 2.5 min and a half-life beta of 26.6 min. After 2 h there was still spin-labeled thio-TE-PA in plasma, but not in tissues. In tissues, no spin-labeled thio-TEPA was detected with gas-liquid chromatography 15 min after injection, but with electron-spin resonance label was found in lung and skeletal muscle. The main metabolite of spin-labeled thio-TEPA is spin-labeled TEPA, where oxidative desulfurization is invoked as the main metabolic mechanism. Reduction of the spin label to the hydroxylamine was also observed with time.

  15. The rotational mobility of spin labels in wool creatine depending on temperature, humidity and deformation

    International Nuclear Information System (INIS)

    Bobodzhanov, P.Kh.; Yusupov, I.Kh.; Marupov, R.

    2001-01-01

    Present article is devoted to study of rotational mobility of spin labels in wool creatine depending on temperature, humidity and deformation. The experimental data of study of structure and molecular mobility of wool creatine modified by spin labels was considered.

  16. Perfusion deficits detected by arterial spin-labeling in patients with TIA with negative diffusion and vascular imaging.

    Science.gov (United States)

    Qiao, X J; Salamon, N; Wang, D J J; He, R; Linetsky, M; Ellingson, B M; Pope, W B

    2013-01-01

    A substantial portion of clinically diagnosed TIA cases is imaging-negative. The purpose of the current study is to determine if arterial spin-labeling is helpful in detecting perfusion abnormalities in patients presenting clinically with TIA. Pseudocontinuous arterial spin-labeling with 3D background-suppressed gradient and spin-echo was acquired on 49 patients suspected of TIA within 24 hours of symptom onset. All patients were free of stroke history and had no lesion-specific findings on general MR, DWI, and MRA sequences. The calculated arterial spin-labeling CBF maps were scored from 1-3 on the basis of presence and severity of perfusion disturbance by 3 independent observers blinded to patient history. An age-matched cohort of 36 patients diagnosed with no cerebrovascular events was evaluated as a control. Interobserver agreement was assessed by use of the Kendall concordance test. Scoring of perfusion abnormalities on arterial spin-labeling scans of the TIA cohort was highly concordant among the 3 observers (W = 0.812). The sensitivity and specificity of arterial spin-labeling in the diagnosis of perfusion abnormalities in TIA was 55.8% and 90.7%, respectively. In 93.3% (70/75) of the arterial spin-labeling CBF map readings with positive scores (≥2), the brain regions where perfusion abnormalities were identified by 3 observers matched with the neurologic deficits at TIA onset. In this preliminary study, arterial spin-labeling showed promise in the detection of perfusion abnormalities that correlated with clinically diagnosed TIA in patients with otherwise normal neuroimaging results.

  17. Superselective pseudo-continuous arterial spin labeling angiography

    Energy Technology Data Exchange (ETDEWEB)

    Jensen-Kondering, Ulf [Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein, Kiel (Germany); Lindner, Thomas, E-mail: thomas.lindner@uksh.de [Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein, Kiel (Germany); Osch, Matthias J.P. van [C. J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden (Netherlands); Rohr, Axel; Jansen, Olav [Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein, Kiel (Germany); Helle, Michael [Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein, Kiel (Germany); Now with Philips GmbH Innovative Technologies, Research Laboratories, Hamburg (Germany)

    2015-09-15

    Highlights: • Superselective arterial spin labeling was capable of acquiring angiograms of individually selected arteries. • Image quality was similar compared with a routinely used time-of-flight angiography. • Superselective arterial spin labeling was utilized in patients with arterio-venous malformations and made it possible to visualize individual feeding vessels in a complete non-invasive way - Abstract: Purpose: To evaluate the utility of a novel non-contrast enhanced, vessel-selective magnetic resonance angiography (MRA) approach based on superselective pseudo-continuous arterial spin labeling (ASL) for the morphologic assessment of intracranial arteries when compared to a clinically used time-of-flight (TOF) MRA. Materials and methods: Three sets of selective ASL angiographies (right and left internal carotid artery, basilar artery) as well as one TOF data set were obtained from each of the five volunteers included in this study on a clinical 1.5T system. The depiction of arterial segments as well as their delineation was evaluated and independently analyzed by two radiologists. Additionally, the ASL angiography approach was performed in two patients suffering from arterio-venous malformations (AVM) in order to illustrate potential applications in a clinical setting. Results: In both angiography techniques, intracranial arteries and their segments (distal branches up to A5 segments of the anterior cerebral arteries, M8 segments of the middle cerebral arteries, and P5 segments of the posterior cerebral arteries) were continuously depicted with excellent inter-reader agreement (κ > 0.81). In AVM patients, reconstructed images of the TOF angiography presented similar information about the size and shape of the AVM as did superselective ASL angiography. In addition, the acquired ASL angiograms of selected vessels allowed assessing the blood supply of individually labeled arteries to the AVM which could also be confirmed by digital subtraction angiography

  18. Superselective pseudo-continuous arterial spin labeling angiography

    International Nuclear Information System (INIS)

    Jensen-Kondering, Ulf; Lindner, Thomas; Osch, Matthias J.P. van; Rohr, Axel; Jansen, Olav; Helle, Michael

    2015-01-01

    Highlights: • Superselective arterial spin labeling was capable of acquiring angiograms of individually selected arteries. • Image quality was similar compared with a routinely used time-of-flight angiography. • Superselective arterial spin labeling was utilized in patients with arterio-venous malformations and made it possible to visualize individual feeding vessels in a complete non-invasive way - Abstract: Purpose: To evaluate the utility of a novel non-contrast enhanced, vessel-selective magnetic resonance angiography (MRA) approach based on superselective pseudo-continuous arterial spin labeling (ASL) for the morphologic assessment of intracranial arteries when compared to a clinically used time-of-flight (TOF) MRA. Materials and methods: Three sets of selective ASL angiographies (right and left internal carotid artery, basilar artery) as well as one TOF data set were obtained from each of the five volunteers included in this study on a clinical 1.5T system. The depiction of arterial segments as well as their delineation was evaluated and independently analyzed by two radiologists. Additionally, the ASL angiography approach was performed in two patients suffering from arterio-venous malformations (AVM) in order to illustrate potential applications in a clinical setting. Results: In both angiography techniques, intracranial arteries and their segments (distal branches up to A5 segments of the anterior cerebral arteries, M8 segments of the middle cerebral arteries, and P5 segments of the posterior cerebral arteries) were continuously depicted with excellent inter-reader agreement (κ > 0.81). In AVM patients, reconstructed images of the TOF angiography presented similar information about the size and shape of the AVM as did superselective ASL angiography. In addition, the acquired ASL angiograms of selected vessels allowed assessing the blood supply of individually labeled arteries to the AVM which could also be confirmed by digital subtraction angiography

  19. Orientation of spin-labeled light chain 2 of myosin heads in muscle fibers.

    Science.gov (United States)

    Arata, T

    1990-07-20

    Electron paramagnetic resonance (e.p.r.) spectroscopy has been used to monitor the orientation of spin labels attached rigidly to a reactive SH residue on the light chain 2 (LC2) of myosin heads in muscle fibers. e.p.r. spectra from spin-labeled myosin subfragment-1 (S1), allowed to diffuse into unlabeled rigor (ATP-free) fibers, were roughly approximated by a narrow angular distribution of spin labels centered at 66 degrees relative to the fiber axis, indicating a uniform orientation of S1 bound to actin. On the other hand, spectra from spin-labeled heavy meromyosin (HMM) were roughly approximated by two narrow angular distributions centered at 42 degrees and 66 degrees, suggesting that the LC2 domains of the two HMM heads have different orientations. In contrast to S1 or HMM, the spectra from rigor fibers, in which LC2 of endogenous myosin heads was labeled, showed a random orientation which may be due to distortion imposed by the structure of the filament lattice and the mismatch of the helical periodicities of the thick and thin filaments. However, spectra from the fibers in the presence of ATP analog 5'-adenylyl imidodiphosphate (AMPPNP) were approximated by two narrow angular distributions similar to those obtained with HMM. Thus, AMPPNP may cause the LC2 domain to be less flexible and/or the S2 portion to be more flexible, so as to release the distortion of the LC2 domain and make it return to its natural position. At high ionic strength, AMPPNP disoriented the spin labels as ATP did under relaxing conditions, suggesting that the myosin head is detached from and/or weakly (flexibly) attached to a thin filament.

  20. Spin label evidence for the role of lysoglycerophosphatides in cellular membranes of hibernating mammals

    Energy Technology Data Exchange (ETDEWEB)

    Keith, A D [Pennsylvania State Univ., University Park; Aloia, R C; Lyons, J; Snipes, W; Pengelley, E T

    1975-01-01

    The phospholipid composition of ground squirrel heart muscle changes during hibernation: more lysoglycerophosphatides are found in the hibernating state than in the active state. Phase transitions inferred from spin label motion occur in the usual manner typical of mammalian mitochondria for the mitochondria and mitochondrial lipids from active squirrels. However, a conspicuous absence of a spin label-detectable phase transition is observed in equivalent preparations from hibernating animals. The addition of lysolecithin to preparations from active squirrels removes the break and induces a straight line in the Arrhenius plot. The lack of a spin label-detectable phase transition in hibernating animals, therefore, is attributed to an increased content of lysoglycerophosphatides present in the phospholipids during hibernation.

  1. Selectively dispersed isotope labeling for protein structure determination by magic angle spinning NMR

    Energy Technology Data Exchange (ETDEWEB)

    Eddy, Matthew T. [Massachusetts Institute of Technology, Department of Chemistry (United States); Belenky, Marina [Brandeis University, Department of Chemistry (United States); Sivertsen, Astrid C. [Massachusetts Institute of Technology, Francis Bitter Magnet Laboratory (United States); Griffin, Robert G. [Massachusetts Institute of Technology, Department of Chemistry (United States); Herzfeld, Judith, E-mail: herzfeld@brandeis.edu [Brandeis University, Department of Chemistry (United States)

    2013-10-15

    The power of nuclear magnetic resonance spectroscopy derives from its site-specific access to chemical, structural and dynamic information. However, the corresponding multiplicity of interactions can be difficult to tease apart. Complimentary approaches involve spectral editing on the one hand and selective isotope substitution on the other. Here we present a new 'redox' approach to the latter: acetate is chosen as the sole carbon source for the extreme oxidation numbers of its two carbons. Consistent with conventional anabolic pathways for the amino acids, [1-{sup 13}C] acetate does not label {alpha} carbons, labels other aliphatic carbons and the aromatic carbons very selectively, and labels the carboxyl carbons heavily. The benefits of this labeling scheme are exemplified by magic angle spinning spectra of microcrystalline immunoglobulin binding protein G (GB1): the elimination of most J-couplings and one- and two-bond dipolar couplings provides narrow signals and long-range, intra- and inter-residue, recoupling essential for distance constraints. Inverse redox labeling, from [2-{sup 13}C] acetate, is also expected to be useful: although it retains one-bond couplings in the sidechains, the removal of CA-CO coupling in the backbone should improve the resolution of NCACX spectra.

  2. EPR and NMR spectroscopy on spin-labeled proteins

    NARCIS (Netherlands)

    Finiguerra, Michelina Giuseppina

    2011-01-01

    Spin labeling and electron paramagnetic resonance (EPR) have been employed to study structure and dynamics of proteins. The surface polarity of four single cysteine mutants of the Zn-azurin in frozen solution were studied using 275 GHz EPR (J-band), with the advantage compared to 9 GHz (X-band) and

  3. Identification of pH-sensitive regions in the mouse prion by the cysteine-scanning spin-labeling ESR technique

    International Nuclear Information System (INIS)

    Watanabe, Yasuko; Inanami, Osamu; Horiuchi, Motohiro; Hiraoka, Wakako; Shimoyama, Yuhei; Inagaki, Fuyuhiko; Kuwabara, Mikinori

    2006-01-01

    We analyzed the pH-induced mobility changes in moPrP C α-helix and β-sheets by cysteine-scanning site-directed spin labeling (SDSL) with ESR. Nine amino acid residues of α-helix1 (H1, codon 143-151), four amino acid residues of β-sheet1 (S1, codon 127-130), and four amino acid residues of β-sheet2 (S2, codon 160-163) were substituted for by cysteine residues. These recombinant mouse PrP C (moPrP C ) mutants were reacted with a methane thiosulfonate sulfhydryl-specific spin labeling reagent (MTSSL). The 1/δH of the central ( 14 N hyperfine) component (M I = 0) in the ESR spectrum of spin-labeled moPrP C was measured as a mobility parameter of nitroxide residues (R1). The mobilities of E145R1 and Y149R1 at pH 7.4, which was identified as a tertiary contact site by a previous NMR study of moPrP, were lower than those of D143R1, R147R1, and R150R1 reported on the helix surface. Thus, the mobility in the H1 region in the neutral solution was observed with the periodicity associated with a helical structure. On the other hand, the values in the S2 region, known to be located in the buried side, were lower than those in the S1 region located in the surface side. These results indicated that the mobility parameter of the nitroxide label was well correlated with the 3D structure of moPrP. Furthermore, the present study clearly demonstrated three pH-sensitive sites in moPrP, i.e. (1) the N-terminal tertiary contact site of H1 (2) the C-terminal end of H1, and (3) the S2 region. In particular, among these pH-sensitive sites, the N-terminal tertiary contact region of H1 was found to be the most pH-sensitive one and was easily converted to a flexible structure by a slight decrease of pH in the solution. These data provided molecular evidence to explain the cellular mechanism for conversion from PrP C to PrP Sc in acidic organelles such as the endosome

  4. Advances in the synthesis of nitroxide radicals for use in biomolecule spin labelling.

    Science.gov (United States)

    Haugland, Marius M; Lovett, Janet E; Anderson, Edward A

    2018-02-05

    EPR spectroscopy is an increasingly useful analytical tool to probe biomolecule structure, dynamic behaviour, and interactions. Nitroxide radicals are the most commonly used radical probe in EPR experiments, and many methods have been developed for their synthesis, as well as incorporation into biomolecules using site-directed spin labelling. In this Tutorial Review, we discuss the most practical methods for the synthesis of nitroxides, focusing on the tunability of their structures, the manipulation of their sidechains into spin labelling handles, and their installation into biomolecules.

  5. Modulating effect of new potential antimelanomic agents, spin-labeled triazenes and nitrosoureas on the DOPA-oxidase activity of tyrosinase.

    Science.gov (United States)

    Gadjeva, V; Zheleva, A; Raikova, E

    1999-07-01

    The modulating effect of newly synthesized alkylating spin labeled triazene and spin labeled nitrosourea derivatives on the DOPA-oxidase activity of mushroom tyrosinase has been investigated by Bumett's spectrophotometric method (Burnett et al., 1967). All spin labeled triazenes have exhibited activating effect on DOPA-oxidase activity of tyrosinase, whereas clinically used triazene (DTIC), which does not contain nitroxide moiety, have showed inhibiting effect. At the same experimental conditions the spin labeled aminoacid nitrosoureas have showed dual effect - activating, in the beginning of the enzyme reaction and inhibiting later on. It is deduced that the activating effect of the spin labeled compounds is due to the nitroxide moiety and the inhibiting effect of all compounds depends on their half-life time. This study might contribute to make more clear the mechanism of action of the new compounds and on the other hand would come in quite useful as a preliminary prognosis for their antimelanomic activity.

  6. The effects of general anesthetics on ESR spectra of spin labels in phosphatidylcholine vesicles containing purified Na,K-ATPase or microsomal protein

    Science.gov (United States)

    Shibuya, Makiko; Hiraoki, Toshifumi; Kimura, Kunie; Fukushima, Kazuaki; Suzuki, Kuniaki

    2012-12-01

    We investigated the effects of general anesthetics on liposome containing spin labels, 5-doxyl stearic acid (5-DSA) and 16-doxyl stearic acid (16-DSA), and purified Na,K-ATPase or membrane protein of microsome using an electron spin resonance (ESR) spectroscopy. The spectra of 16-DSA in liposomes with both proteins showed three sharp signals compared with 5-DSA. The difference in the order parameter S value of 5-DSA and 16-DSA suggested that the nitroxide radical location of 5-DSA and 16-DSA were different in the membrane bilayer. The results were almost the same as those obtained in liposomes without proteins. The addition of sevoflurane, isoflurane, halothane, ether, ethanol and propofol increased the intensity of the signals, but the clinical concentrations of anesthetics did not significantly alter the S and τ values, which are indices of the fluidity of the membrane. These results suggest that anesthetics remain on the surface of the lipid bilayer and do not act on both the inside hydrophobic area and the relatively hydrophilic area near the surface. These results and others also suggest that the existence of Na,K-ATPase and microsomal proteins did not affect the environment around the spin labels in the liposome and the effects of anesthetics on liposome as a model membrane.

  7. Effect of some radiosensitising drugs on human erythrocyte membrane - - spin label study

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, K P [Bhabha Atomic Research Centre, Bombay (India). Biology and Agriculture Div.

    1982-02-01

    Electron spin resonance and spin label techniques have been employed to study the effects of local anaesthetic drugs, procaine and tetracaine, on human erythrocyte membrane. Both the drugs altered the protein and lipid arrangements in the membrane and these changes were reversible. Procaine had greater effect on the labels attached to proteins while tetracaine fluidized interior of lipid bilayer to a greater extent. The differential effects of these drugs on the protein and lipid labels have been interpreted in terms of their relative penetrability in the membrane. Present results have explained that radiation induced enhanced killing of cells in the presence of these drugs might be due to the alterations in membrane, particularly proteins both structural and enzymatic. In addition, these results indicate a possible relationship between drug-induced structural changes in membrane and their anaesthetic potency.

  8. Stereoselective synthesis of stable-isotope-labeled amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Unkefer, C.J.; Martinez, R.A.; Silks, L.A. III [Los Alamos National Laboratory, NM (United States); Lodwig, S.N. [Centralia College, WA (United States)

    1994-12-01

    For magnetic resonance and vibrational spectroscopies to reach their full potential, they must be used in combination with sophisticated site-specific stable isotope labeling of biological macromolecules. Labeled amino acids are required for the study of the structure and function of enzymes and proteins. Because there are 20 common amino acids, each with its own distinguishing chemistry, they remain a synthetic challenge. The Oppolzer chiral auxiliary provides a general tool with which to approach the synthesis of labeled amino acids. By using the Oppolzer auxiliary, amino acids can be constructed from several small molecules, which is ideal for stable isotope labeling. In addition to directing the stereochemistry at the {alpha}-carbon, the camphorsultam can be used for stereo-specific isotope labeling at prochiral centers in amino acids. By using the camphorsultam auxiliary we have the potential to synthesize virtually any isotopomer of all of the common amino acids.

  9. Stereoselective synthesis of stable-isotope-labeled amino acids

    International Nuclear Information System (INIS)

    Unkefer, C.J.; Martinez, R.A.; Silks, L.A. III; Lodwig, S.N.

    1994-01-01

    For magnetic resonance and vibrational spectroscopies to reach their full potential, they must be used in combination with sophisticated site-specific stable isotope labeling of biological macromolecules. Labeled amino acids are required for the study of the structure and function of enzymes and proteins. Because there are 20 common amino acids, each with its own distinguishing chemistry, they remain a synthetic challenge. The Oppolzer chiral auxiliary provides a general tool with which to approach the synthesis of labeled amino acids. By using the Oppolzer auxiliary, amino acids can be constructed from several small molecules, which is ideal for stable isotope labeling. In addition to directing the stereochemistry at the α-carbon, the camphorsultam can be used for stereo-specific isotope labeling at prochiral centers in amino acids. By using the camphorsultam auxiliary we have the potential to synthesize virtually any isotopomer of all of the common amino acids

  10. Characterization of Bifunctional Spin Labels for Investigating the Structural and Dynamic Properties of Membrane Proteins Using EPR Spectroscopy.

    Science.gov (United States)

    Sahu, Indra D; Craig, Andrew F; Dunagum, Megan M; McCarrick, Robert M; Lorigan, Gary A

    2017-10-05

    Site-directed spin labeling (SDSL) coupled with electron paramagnetic resonance (EPR) spectroscopy is a very powerful technique to study structural and dynamic properties of membrane proteins. The most widely used spin label is methanthiosulfonate (MTSL). However, the flexibility of this spin label introduces greater uncertainties in EPR measurements obtained for determining structures, side-chain dynamics, and backbone motion of membrane protein systems. Recently, a newer bifunctional spin label (BSL), 3,4-bis(methanethiosulfonylmethyl)-2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrol-1-yloxy, has been introduced to overcome the dynamic limitations associated with the MTSL spin label and has been invaluable in determining protein backbone dynamics and inter-residue distances due to its restricted internal motion and fewer size restrictions. While BSL has been successful in providing more accurate information about the structure and dynamics of several proteins, a detailed characterization of the spin label is still lacking. In this study, we characterized BSLs by performing CW-EPR spectral line shape analysis as a function of temperature on spin-labeled sites inside and outside of the membrane for the integral membrane protein KCNE1 in POPC/POPG lipid bilayers and POPC/POPG lipodisq nanoparticles. The experimental data revealed a powder pattern spectral line shape for all of the KCNE1-BSL samples at 296 K, suggesting the motion of BSLs approaches the rigid limit regime for these series of samples. BSLs were further utilized to report for the first time the distance measurement between two BSLs attached on an integral membrane protein KCNE1 in POPC/POPG lipid bilayers at room temperature using dipolar line broadening CW-EPR spectroscopy. The CW dipolar line broadening EPR data revealed a 15 ± 2 Å distance between doubly attached BSLs on KCNE1 (53/57-63/67) which is consistent with molecular dynamics modeling and the solution NMR structure of KCNE1 which yielded a

  11. Comparing model-based and model-free analysis methods for QUASAR arterial spin labeling perfusion quantification.

    Science.gov (United States)

    Chappell, Michael A; Woolrich, Mark W; Petersen, Esben T; Golay, Xavier; Payne, Stephen J

    2013-05-01

    Amongst the various implementations of arterial spin labeling MRI methods for quantifying cerebral perfusion, the QUASAR method is unique. By using a combination of labeling with and without flow suppression gradients, the QUASAR method offers the separation of macrovascular and tissue signals. This permits local arterial input functions to be defined and "model-free" analysis, using numerical deconvolution, to be used. However, it remains unclear whether arterial spin labeling data are best treated using model-free or model-based analysis. This work provides a critical comparison of these two approaches for QUASAR arterial spin labeling in the healthy brain. An existing two-component (arterial and tissue) model was extended to the mixed flow suppression scheme of QUASAR to provide an optimal model-based analysis. The model-based analysis was extended to incorporate dispersion of the labeled bolus, generally regarded as the major source of discrepancy between the two analysis approaches. Model-free and model-based analyses were compared for perfusion quantification including absolute measurements, uncertainty estimation, and spatial variation in cerebral blood flow estimates. Major sources of discrepancies between model-free and model-based analysis were attributed to the effects of dispersion and the degree to which the two methods can separate macrovascular and tissue signal. Copyright © 2012 Wiley Periodicals, Inc.

  12. Saturation recovery EPR spin-labeling method for quantification of lipids in biological membrane domains.

    Science.gov (United States)

    Mainali, Laxman; Camenisch, Theodore G; Hyde, James S; Subczynski, Witold K

    2017-12-01

    The presence of integral membrane proteins induces the formation of distinct domains in the lipid bilayer portion of biological membranes. Qualitative application of both continuous wave (CW) and saturation recovery (SR) electron paramagnetic resonance (EPR) spin-labeling methods allowed discrimination of the bulk, boundary, and trapped lipid domains. A recently developed method, which is based on the CW EPR spectra of phospholipid (PL) and cholesterol (Chol) analog spin labels, allows evaluation of the relative amount of PLs (% of total PLs) in the boundary plus trapped lipid domain and the relative amount of Chol (% of total Chol) in the trapped lipid domain [ M. Raguz, L. Mainali, W. J. O'Brien, and W. K. Subczynski (2015), Exp. Eye Res., 140:179-186 ]. Here, a new method is presented that, based on SR EPR spin-labeling, allows quantitative evaluation of the relative amounts of PLs and Chol in the trapped lipid domain of intact membranes. This new method complements the existing one, allowing acquisition of more detailed information about the distribution of lipids between domains in intact membranes. The methodological transition of the SR EPR spin-labeling approach from qualitative to quantitative is demonstrated. The abilities of this method are illustrated for intact cortical and nuclear fiber cell plasma membranes from porcine eye lenses. Statistical analysis (Student's t -test) of the data allowed determination of the separations of mean values above which differences can be treated as statistically significant ( P ≤ 0.05) and can be attributed to sources other than preparation/technique.

  13. Perfusion by Arterial Spin labelling following Single dose Tadalafil In Small vessel disease (PASTIS)

    DEFF Research Database (Denmark)

    Pauls, Mathilde M H; Clarke, Natasha; Trippier, Sarah

    2017-01-01

    vascular territories. The aim of this trial is to test the hypothesis that tadalafil increases cerebral blood flow in older people with small vessel disease. METHODS/DESIGN: Perfusion by Arterial Spin labelling following Single dose Tadalafil In Small vessel disease (PASTIS) is a phase II randomised double......-blind crossover trial. In two visits, 7-30 days apart, participants undergo arterial spin labelling to measure cerebral blood flow and a battery of cognitive tests, pre- and post-dosing with oral tadalafil (20 mg) or placebo. SAMPLE SIZE: 54 participants are required to detect a 15% increase in cerebral blood...

  14. Lesion-induced DNA weak structural changes detected by pulsed EPR spectroscopy combined with site-directed spin labelling.

    Science.gov (United States)

    Sicoli, Giuseppe; Mathis, Gérald; Aci-Sèche, Samia; Saint-Pierre, Christine; Boulard, Yves; Gasparutto, Didier; Gambarelli, Serge

    2009-06-01

    Double electron-electron resonance (DEER) was applied to determine nanometre spin-spin distances on DNA duplexes that contain selected structural alterations. The present approach to evaluate the structural features of DNA damages is thus related to the interspin distance changes, as well as to the flexibility of the overall structure deduced from the distance distribution. A set of site-directed nitroxide-labelled double-stranded DNA fragments containing defined lesions, namely an 8-oxoguanine, an abasic site or abasic site analogues, a nick, a gap and a bulge structure were prepared and then analysed by the DEER spectroscopic technique. New insights into the application of 4-pulse DEER sequence are also provided, in particular with respect to the spin probes' positions and the rigidity of selected systems. The lesion-induced conformational changes observed, which were supported by molecular dynamics studies, confirm the results obtained by other, more conventional, spectroscopic techniques. Thus, the experimental approaches described herein provide an efficient method for probing lesion-induced structural changes of nucleic acids.

  15. Improving the Grading Accuracy of Astrocytic Neoplasms Noninvasively by Combining Timing Information with Cerebral Blood Flow: A Multi-TI Arterial Spin-Labeling MR Imaging Study.

    Science.gov (United States)

    Yang, S; Zhao, B; Wang, G; Xiang, J; Xu, S; Liu, Y; Zhao, P; Pfeuffer, J; Qian, T

    2016-12-01

    Systematic and accurate glioma grading has clinical significance. We present the utility of multi-TI arterial spin-labeling imaging and provide the bolus arrival time maps for grading astrocytomas. Forty-three patients with astrocytomas (21 men; mean age, 51 years) were recruited. The classification abilities of conventional MR imaging features, normalized CBF value derived from multi-TI arterial spin-labeling imaging, normalized bolus arrival time, and normalized CBF derived from single-TI arterial spin-labeling were compared in patients with World Health Organization (WHO) grade II, III, and IV astrocytomas. The normalized CBF value derived from multi-TI arterial spin-labeling imaging was higher in patients with higher grade astrocytoma malignancies compared with patients with lower grade astrocytomas, while the normalized bolus arrival time showed the opposite tendency. The normalized CBF value derived from the multi-TI arterial spin-labeling imaging showed excellent performance with areas under the receiver operating characteristic curve of 0.813 (WHO II versus III), 0.964 (WHO II versus IV), 0.872 (WHO III versus IV), and 0.883 (low-grade-versus-high-grade gliomas). The normalized CBF value derived from single-TI arterial spin-labeling imaging could statistically differentiate the WHO II and IV groups (area under the receiver operating characteristic curve = 0.826). The normalized bolus arrival time effectively identified the WHO grades II and III with an area under the receiver operating characteristic curve of 0.836. Combining the normalized CBF value derived from multi-TI arterial spin-labeling imaging and normalized bolus arrival time improved the diagnostic accuracy from 65.10% to 72.10% compared with the normalized CBF value derived from multi-TI arterial spin-labeling imaging being applied independently. The combination of multi-TI arterial spin-labeling imaging and conventional MR imaging had the best performance, with a diagnostic accuracy of 81

  16. In vivo and ex vivo EPR detection of spin-labelled ovalbumin in mice.

    Science.gov (United States)

    Abramović, Zrinka; Brgles, Marija; Habjanec, Lidija; Tomasić, Jelka; Sentjurc, Marjeta; Frkanec, Ruza

    2010-10-01

    In this study, spin-labelled ovalbumin (SL-OVA), free or entrapped in liposomes, was administered to mice subcutaneously (s.c.) or intravenously (i.v.) with the aim to determine the conditions for pharmacokinetic studies of spin-labelled proteins by EPR and to measure the time course of SL-OVA distribution in vivo in live mice and ex vivo in isolated organs. Upon s.c. administration, the decay of the EPR signal was followed for 60min at the site of application using an L-band EPR spectrometer. Within this time period, the signal of free SL-OVA was diminished by about 70%. It was estimated with the help of the oxidizing agent K(3)[(FeCN)(6)] that approximately 30% was a consequence of the spin label reduction to EPR non-visible hydroxylamine and about 40% was due to the SL-OVA elimination from the site of measurement. For liposome encapsulated SL-OVA, the intensity diminished only by approx. 40% in the same period, indicating that liposomes successfully protect the protein from reduction. EPR signal could not be detected directly over live mouse organs within 60min after s.c. application of SL-OVA. With the available L-band EPR spectrometer, the measurements at the site of s.c. application are possible if the amount of SL-OVA applied to a mouse is more than 3mg. For the pharmacokinetic studies of the protein distribution in organs after s.c. or i.v. injection the concentration of the spin-labelled protein should be more than 0.5mmol/kg. After i.v. administration, only ex vivo measurements were possible using an X-band EPR spectrometer, since the total amount of SL-OVA was not sufficient for in vivo detection and also because of rapid reduction of nitroxide. After 2min, the protein was preferentially distributed to liver and, to a smaller extent, to spleen.

  17. SimLabel: a graphical user interface to simulate continuous wave EPR spectra from site-directed spin labeling experiments.

    Science.gov (United States)

    Etienne, E; Le Breton, N; Martinho, M; Mileo, E; Belle, V

    2017-08-01

    Site-directed spin labeling (SDSL) combined with continuous wave electron paramagnetic resonance (cw EPR) spectroscopy is a powerful technique to reveal, at the residue level, structural transitions in proteins. SDSL-EPR is based on the selective grafting of a paramagnetic label on the protein under study, followed by cw EPR analysis. To extract valuable quantitative information from SDSL-EPR spectra and thus give reliable interpretation on biological system dynamics, numerical simulations of the spectra are required. Such spectral simulations can be carried out by coding in MATLAB using functions from the EasySpin toolbox. For non-expert users of MATLAB, this could be a complex task or even impede the use of such simulation tool. We developed a graphical user interface called SimLabel dedicated to run cw EPR spectra simulations particularly coming from SDSL-EPR experiments. Simlabel provides an intuitive way to visualize, simulate, and fit such cw EPR spectra. An example of SDSL-EPR spectra simulation concerning the study of an intrinsically disordered region undergoing a local induced folding is described and discussed. We believe that this new tool will help the users to rapidly obtain reliable simulated spectra and hence facilitate the interpretation of their results. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  18. Imaging with 123I labelled fatty acids

    International Nuclear Information System (INIS)

    Dudczak, R.

    1985-01-01

    This report describes the clinical results obtained with radioiodinated aromatic and aliphatic fatty acids. The radiopharmaceuticals were 123 I labelled p-phenylpentadecanoic (p-IPPA) and 123 I labelled heptadecanoic acid (HDA). The possibility to evaluate the myocardial metabolic function in man noninvasively add a complementary diagnostic tool in the clinical follow-up of patients with heart disease. (Auth.)

  19. DNA with Parallel Strand Orientation: A Nanometer Distance Study with Spin Labels in the Watson-Crick and the Reverse Watson-Crick Double Helix.

    Science.gov (United States)

    Wunnicke, Dorith; Ding, Ping; Yang, Haozhe; Seela, Frank; Steinhoff, Heinz-Jürgen

    2015-10-29

    Parallel-stranded (ps) DNA characterized by its sugar-phosphate backbones pointing in the same direction represents an alternative pairing system to antiparallel-stranded (aps) DNA with the potential to inhibit transcription and translation. 25-mer oligonucleotides were selected containing only dA·dT base pairs to compare spin-labeled nucleobase distances over a range of 10 or 15 base pairs in ps DNA with those in aps DNA. By means of the copper(I)-catalyzed Huisgen-Meldal-Sharpless alkyne-azide cycloaddition, the spin label 4-azido-2,2,6,6-tetramethylpiperidine-1-oxyl was clicked to 7-ethynyl-7-deaza-2'-deoxyadenosine or 5-ethynyl-2'-deoxyuridine to yield 25-mer oligonucleotides incorporating two spin labels. The interspin distances between spin labeled residues were determined by pulse EPR spectroscopy. The results reveal that in ps DNA these distances are between 5 and 10% longer than in aps DNA when the labeled DNA segment is located near the center of the double helix. The interspin distance in ps DNA becomes shorter compared with aps DNA when one of the spin labels occupies a position near the end of the double helix.

  20. Labeling of unnatural amino acids with sup(99m)Tc and tissue distribution of the labeled products in mice

    International Nuclear Information System (INIS)

    Tamemasa, Osamu; Goto, Rensuke; Takeda, Atsushi

    1981-01-01

    The selective affinity of amino acids for pancreas, due to its high rate of protein synthesis, has prompted us to synthesize new radio-labeled amino acids for pancreatic imaging. Labeling of 19 unnatural amino acids with sup(99m)Tc was tried in the usual way, and 10 labeled products were obtained with low yields. The highest distribution of radioactivity from all these labeled amino acids, which had been injected intravenously into mice, was found in the kidney, whereas little activity was found in the pancreas. Their low distributions in stomach suggest little dissociation of the labeled amino acids into sup(99m)TcO 4 - in mice. It is presumed that these labeled amino acids behave unlike their original amino acids in the body. (author)

  1. Fatty acids labelled in the. omega. -position with iodine isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Mathieu, J.P.; Busquet, G.; Comet, M. (Universite Scientifique et Medicale de Grenoble, 38 - La Tronche (France)); Riche, F.; Vidal, M. (Laboratoire d' Etudes Dynamiques et Structurales de la Selectivite, 38 - Grenoble (France)); Coornaert, S.; Bardy, A. (CEA, Centre de Saclay, 91 - Gif-sur-Yvette (France)); Godart, J. (Institut des Sciences Nucleaires, 38 - Grenoble (France))

    1982-01-01

    The synthesis of saturated acetylenic and olefinic (Z or E) ..omega..-iodinated fatty acids has been carried out and their labelling with iodine-131 or 123 by exchange I/sup -/, *I/sup -/ has been studied. The influence of several parameters -water and fatty acid concentrations, specific activity, labelling solution acidity, iodine carrier presence- on this exchange reaction has been noted, enabling experimental conditions to be defined that produce labelling yields of greater than 95%. These results should lead to widespread clinical use of iodine labelled fatty acids.

  2. Coherence transfer and electron T1-, T2-relaxation in nitroxide spin labels

    DEFF Research Database (Denmark)

    Marsh, Derek

    2017-01-01

    -hyperfine anisotropies of isolated nitroxide spin labels. Results compatible with earlier treatments by Redfield theory are obtained without specifically evaluating matrix elements. Extension to single-transition operators for isolated nitroxides predicts electron coherence transfer by pseudosecular electron...

  3. Correlation between the rate of bioreduction of nitroxide spin label by human tumor cells and their low-dose radiation response

    International Nuclear Information System (INIS)

    Halpern, H.J.; Peric, M.; Nguyen, T.D.; Spencer, D.P.; Bowman, M.K.; Beckett, M.; Weichselbaum, R.R.

    1988-01-01

    The authors discuss a correlation observed between the bioreduction of nitroxide spin label by four human tumor cell lines and a normal tissue fibroblast clone and their low-dose radiation response, specifically their D Q . In measurements of the bioreduction rate of several other cell lines, this correlation appears to persist. In order to define the mechanism of this correlation, they have begun by subtly altering the measurement conditions. The original conditions for measurement involved adding the spin label to cells whose culture medium had been changed (the label was added to the new medium). By delaying the addition of the label to the culture medium, they substantially reduced the variation of the bioreduction rate between the cell lines. This implies that the fresh medium provides a nonspecific irritant or disequilibrium to the cultured cell system to which they response variably by accelerating, among other things, the metabolic process responsible for spin label bioreduction

  4. High-level production of C-11-carboxyl-labeled amino acids

    International Nuclear Information System (INIS)

    Washburn, L.C.; Sun, T.T.; Byrd, B.L.; Hayes, R.L.; Butler, T.A.; Callahan, A.P.

    1979-01-01

    Carbon-11-labeled amino acids have significant potential as agents for positron tomographic functional imaging. We have developed a rapid, high-temperature, high-pressure modification of the Buecherer--Strecker amino acid synthesis and found it to be quite general for the production of C-11-carboxyl-labeled neutral amino acids. Production of C-11-carboxyl-labeled DL-tryptophan requires certain modifications in the procedure. Twelve different amino acids have been produced to date by this technique. Synthesis and chromatographic purification require approximately 40 min, and C-11-carboxyl-labeled amino acids have been produced in yields of up to 425 mCi. Two C-11-carboxyl-labeled amino acids are being investigated clinically for tumor scanning and two others for pancreatic imaging. Over 120 batches of the various agents have been produced for clinical use over a three-year period

  5. Microwave assistance of labeling hippuric acid by I-131

    International Nuclear Information System (INIS)

    Sherlock Huang, Lin-Chiang; Wu, Kou-Hung; Ko, Pi-Wen; Hsieh, Cheng-Ying; Pao, Kuan-Chuan; Chou, Shih-Ching; Shieh, Fa-Kuen; Sureshbabu, Radhakrishnan; Hsu, Ming-Hua

    2014-01-01

    This work presents a novel approach for labeling hippuric acid with I-131 using microwaves. It utilizes copper(II) acetate as a catalyst of the labeling. The process involves the use of this catalytic copper(II) acetate at low dilutions that were nevertheless sufficient to produce labeled hippuric acid with high radiochemical purity in a short time. Therefore, the novel technique overcomes the limitations of previously reported conventional methods that involve heating. - Highlights: • We report the microwave assisted radiochemical labeling of hippuric acid by I-131. • Cu(OAc) 2 can be used as catalyst to get labeled product in lower dilution condition. • Advantages of our method are lesser time scale and high radiochemical purity.

  6. N-13 labeled amino acids: biodistribution, metabolism and dosimetric considerations

    International Nuclear Information System (INIS)

    Rosenspire, K.C.; Gelbard, A.S.

    1986-01-01

    With the growing interest in metabolic imaging and with the increasing number of cyclotron/PET facilities, more studies are being performed in animal and humans using short-lived positron-emitting radionuclides. Amino acids labeled either with N-13 or C-11 are one group of compounds being used to study in vivo regional organ (i.e., brain and heart) or tumor metabolism. Of the studies previously reported using C-11 or N-13 labeled amino acids (methionine, alanine, valine, glutamate, glutamine and tryptophan), imaging was restricted mainly to the organ or tissue of interest with little information obtained about the whole-bode distribution of the label. Such data are important for studying interorgan transport of amino acids and for determining accurate dosimetric measurements after intravenous injection of labeled amino acids. The goals of the authors study were to compare the distribution of several N-13 L-amino acids and N-13 ammonia in tumor-bearing mice and to determine the metabolic fate of the label in vivo. The following amino acids were enzymatically labeled using N-13 ammonia: glutamine, glutamate, methionine, α-aminobutyric acid, valine and leucine. 30 references, 2 figures, 14 tables

  7. An improved synthesis of carbon-14 labelled carboxylic acids from carbon-14 labelled amino acids

    International Nuclear Information System (INIS)

    Ramamurthy, T.V.; Ravi, S.; Viswanathan, K.V.

    1988-01-01

    Various carbon-14 labelled amino acids including the aromatic ones viz., tyrosine, phenylalanine and tryptophan are converted to the corresponding carboxylic acids in high yield (70-90%) on a micromolar scale synthesis by reaction with hydroxyl-amine-O-sulphonic acid and in a short reaction time. The improvement in yield has been achieved by using aqeuous alcohol as solvent in lieu of water alone as the medium of reaction. (author)

  8. Noninvasive measurements of regional cerebral perfusion in preterm and term neonates by magnetic resonance arterial spin labeling

    DEFF Research Database (Denmark)

    Miranda Gimenez-Ricco, Maria Jo; Olofsson, K; Sidaros, Karam

    2006-01-01

    Magnetic resonance arterial spin labeling (ASL) at 3 Tesla has been investigated as a quantitative technique for measuring regional cerebral perfusion (RCP) in newborn infants. RCP values were measured in 49 healthy neonates: 32 preterm infants born before 34 wk of gestation and 17 term-born neon......Magnetic resonance arterial spin labeling (ASL) at 3 Tesla has been investigated as a quantitative technique for measuring regional cerebral perfusion (RCP) in newborn infants. RCP values were measured in 49 healthy neonates: 32 preterm infants born before 34 wk of gestation and 17 term...

  9. Synthesis of some labelled non-proteinogenic amino acids

    International Nuclear Information System (INIS)

    Adrianens, P.; Vanderhaeghe, H.

    1987-01-01

    The literature on the synthesis of labeled non-proteinogenic amino acids contains approximately 300 papers, whereas syntheses of labeled proteinogenic amino acids are dealt with in some 800-1000 publications. However, most of the methods described in this paper for the synthesis of non-proteinogenic amino acids are also used for the preparation of the essential amino acids addition, the first category also contains β, γ...amino acids, seleno amino acids, N-methyl and α-methyl amino acids and sometimes have atoms or groups which are not present in the protein building blocks. Furthermore the latter group is more easily available so that methods for synthesis of non-proteinogenic amino acids are more needed

  10. Sequences of 12 monoclonal anti-dinitrophenyl spin-label antibodies for NMR studies

    International Nuclear Information System (INIS)

    Leahy, D.J.; Rule, G.S.; Whittaker, M.M.; McConnell, H.M.

    1988-01-01

    Eleven monoclonal antibodies specific for a spin-labeled dinitrophenyl hapten (DNP-SL) have been produces for use in NMR studies. They have been named AN01 and ANO3-AN12. The stability constants for the association of these antibodies with DNP-SL and related haptens were measured by fluorescence quenching. cDNA clones coding for the heavy and light chains of each antibody and of an additional anti-DNP-SL monoclonal antibody, ANO2, have been isolated. The nucleic acid sequence of the 5' end of each clone has been determined, and the amino acid sequence of the variable regions of each antibody has been deduced from the cDNA sequence. The sequences are relatively heterogeneous, but both the heavy and the light chains of ANO1 and ANO3 are derived from the same variable-region gene families as those of the ANO2 antibody. ANO7 has a heavy chain that is related to that of ANO2, and ANO9 has a related light chain. ANO5 and ANO6 are unrelated to ANO2 but share virtually identical heavy and light chains. Preliminary NMR difference spectra comparing related antibodies show that sequence-specific assignment of resonances is possible. Such spectra also provide a measure of structural relatedness

  11. Head-to-Head Visual Comparison between Brain Perfusion SPECT and Arterial Spin-Labeling MRI with Different Postlabeling Delays in Alzheimer Disease.

    Science.gov (United States)

    Kaneta, T; Katsuse, O; Hirano, T; Ogawa, M; Yoshida, K; Odawara, T; Hirayasu, Y; Inoue, T

    2017-08-01

    Arterial spin-labeling MR imaging has been recently developed as a noninvasive technique with magnetically labeled arterial blood water as an endogenous contrast medium for the evaluation of CBF. Our aim was to compare arterial spin-labeling MR imaging and SPECT in the visual assessment of CBF in patients with Alzheimer disease. In 33 patients with Alzheimer disease or mild cognitive impairment due to Alzheimer disease, CBF images were obtained by using both arterial spin-labeling-MR imaging with a postlabeling delay of 1.5 seconds and 2.5 seconds (PLD 1.5 and PLD 2.5 , respectively) and brain perfusion SPECT. Twenty-two brain regions were visually assessed, and the diagnostic confidence of Alzheimer disease was recorded. Among all arterial spin-labeling images, 84.9% of PLD 1.5 and 9% of PLD 2.5 images showed the typical pattern of advanced Alzheimer disease (ie, decreased CBF in the bilateral parietal, temporal, and frontal lobes). PLD 1.5 , PLD 2.5 , and SPECT imaging resulted in obviously different visual assessments. PLD 1.5 showed a broad decrease in CBF, which could have been due to an early perfusion. In contrast, PLD 2.5 did not appear to be influenced by an early perfusion but showed fewer pathologic findings than SPECT. The distinctions observed by us should be carefully considered in the visual assessments of Alzheimer disease. Further studies are required to define the patterns of change in arterial spin-labeling-MR imaging associated with Alzheimer disease. © 2017 by American Journal of Neuroradiology.

  12. Characterizing Active Pharmaceutical Ingredient Binding to Human Serum Albumin by Spin-Labeling and EPR Spectroscopy.

    Science.gov (United States)

    Hauenschild, Till; Reichenwallner, Jörg; Enkelmann, Volker; Hinderberger, Dariush

    2016-08-26

    Drug binding to human serum albumin (HSA) has been characterized by a spin-labeling and continuous-wave (CW) EPR spectroscopic approach. Specifically, the contribution of functional groups (FGs) in a compound on its albumin-binding capabilities is quantitatively described. Molecules from different drug classes are labeled with EPR-active nitroxide radicals (spin-labeled pharmaceuticals (SLPs)) and in a screening approach CW-EPR spectroscopy is used to investigate HSA binding under physiological conditions and at varying ratios of SLP to protein. Spectral simulations of the CW-EPR spectra allow extraction of association constants (KA ) and the maximum number (n) of binding sites per protein. By comparison of data from 23 SLPs, the mechanisms of drug-protein association and the impact of chemical modifications at individual positions on drug uptake can be rationalized. Furthermore, new drug modifications with predictable protein binding tendency may be envisaged. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Arterial spin labelling in imaging of renal diseases and renal allograft pathology; MRT-Perfusionsmessung mit Arterial Spin Labelling. Anwendung fuer die Niere und Transplantatniere

    Energy Technology Data Exchange (ETDEWEB)

    Hueper, Katja; Gutberlet, Marcel [Medizinische Hochschule Hannover (Germany). Inst. fuer Diagnostische und Interventionelle Radiologie; Kuehn, Bernd [Siemens AG/Siemens Healthcare GmbH, Erlangen (Germany)

    2016-06-15

    Arterial Spin Labelling (ASL) is a technique for non-invasive and contrast-free assessment of perfusion with MRI. Renal ASL allows examination of renal pathophysiology, evaluation of the course of renal disease and therapy effects by longitudinal measurements as well as characterization of renal tumors. In this article, techniques of ASL will be explained and challenges of renal ASL will be emphasized. In addition, examples for clinical application of ASL for diagnosis of renal disease and renal allograft pathology will be given.

  14. Electron paramagnetic resonance (EPR spectral components of spin-labeled lipids in saturated phospholipid bilayers: effect of cholesterol

    Directory of Open Access Journals (Sweden)

    Heverton Silva Camargos

    2013-01-01

    Full Text Available Electron paramagnetic resonance (EPR spectroscopy was used to study the main structural accommodations of spin labels in bilayers of saturated phosphatidylcholines with acyl chain lengths ranging from 16 to 22 carbon atoms. EPR spectra allowed the identification of two distinct spectral components in thermodynamic equilibrium at temperatures below and above the main phase transition. An accurate analysis of EPR spectra, using two fitting programs, enabled determination of the thermodynamic profile for these major probe accommodations. Focusing the analysis on two-component EPR spectra of a spin-labeled lipid, the influence of 40 mol % cholesterol in DPPC was studied.

  15. Improved calculation of the equilibrium magnetization of arterial blood in arterial spin labeling

    DEFF Research Database (Denmark)

    Ahlgren, André; Wirestam, Ronnie; Knutsson, Linda

    2018-01-01

    PURPOSE: To propose and assess an improved method for calculating the equilibrium magnetization of arterial blood ( M0a), used for calibration of perfusion estimates in arterial spin labeling. METHODS: Whereas standard M0a calculation is based on dividing a proton density-weighted image by an ave...

  16. Sequence- and structure-dependent DNA base dynamics: Synthesis, structure, and dynamics of site and sequence specifically spin-labeled DNA

    International Nuclear Information System (INIS)

    Spaltenstein, A.; Robinson, B.H.; Hopkins, P.B.

    1989-01-01

    A nitroxide spin-labeled analogue of thymidine (1a), in which the methyl group is replaced by an acetylene-tethered nitroxide, was evaluated as a probe for structural and dynamics studies of sequence specifically spin-labeled DNA. Residue 1a was incorporated into synthetic deoxyoligonucleotides by using automated phosphite triester methods. 1 H NMR, CD, and thermal denaturation studies indicate that 1a (T) does not significantly alter the structure of 5'-d(CGCGAATT*CGCG) from that of the native dodecamer. EPR studies on monomer, single-stranded, and duplexed DNA show that 1a readily distinguishes environments of different rigidity. Comparison of the general line-shape features of the observed EPR spectra of several small duplexes (12-mer, 24-mer) with simulated EPR spectra assuming isotropic motion suggests that probe 1a monitors global tumbling of small duplexes. Increasing the length of the DNA oligomers results in significant deviation from isotropic motion, with line-shape features similar to those of calculated spectra of objects with isotropic rotational correlation times of 20-100 ns. EPR spectra of a spin-labeled GT mismatch and a T bulge in long DNAs are distinct from those of spin-labeled Watson-Crick paired DNAs, further demonstrating the value of EPR as a tool in the evaluation of local dynamic and structural features in macromolecules

  17. Tritium-labelled abscisic acid

    International Nuclear Information System (INIS)

    Pluciennik, H.; Michalski, L.

    1991-01-01

    A simple method for the preparation of biologically active abscisic acid (growth inhibiting plant hormone) labelled with tritium is described. The product obtained has a specific radioactivity of 1.12 GBq mmol -1 : the yield is about 60% as compared to the initial amount of the substance used. (author) 7 refs.; 2 figs

  18. Medial Occipital Lobe Hyperperfusion Identified by Arterial Spin-Labeling: A Poor Prognostic Sign in Patients with Hypoxic-Ischemic Encephalopathy.

    Science.gov (United States)

    de Havenon, A; Sultan-Qurraie, A; Tirschwell, D; Cohen, W; Majersik, J; Andre, J B

    2015-12-01

    Hypoxic-ischemic encephalopathy carries an uncertain prognosis. We sought to retrospectively assess the prognostic value of arterial spin-labeling MR imaging in 22 adult patients diagnosed with hypoxic-ischemic encephalopathy. Quantitative CBF maps were generated from the M0 map, and arterial spin-labeling data on a per-voxel basis were regionally interrogated via visual inspection and ROI placement. Hyperperfusion was defined as regional increases in CBF of >20% (relative to global CBF) and/or >100 mL/100 g/min. Eleven of 22 patients had prominent bilateral medial occipital lobe hyperperfusion, all of whom died before hospital discharge. One patient who had nondistinct arterial spin-labeling hyperperfusion and restricted diffusion survived. Medial occipital lobe hyperperfusion is a distinctive pattern that merits prospective investigation in a cohort of patients with moderate hypoxic-ischemic encephalopathy to determine its predictive ability in patients with a higher likelihood of survival. © 2015 by American Journal of Neuroradiology.

  19. Exploring the local conformational space of a membrane protein by site-directed spin labeling

    NARCIS (Netherlands)

    Stopar, D.; Strancar, J.; Spruijt, R.B.; Hemminga, M.A.

    2005-01-01

    Molecular modeling based on a hybrid evolutionary optimization and an information condensation algorithm, called GHOST, of spin label ESR spectra was applied to study the structure and dynamics of membrane proteins. The new method is capable of providing detailed molecular information about the

  20. Resting quantitative cerebral blood flow in schizophrenia measured by pulsed arterial spin labeling perfusion MRI

    OpenAIRE

    Pinkham, Amy; Loughead, James; Ruparel, Kosha; Wu, Wen-Chau; Overton, Eve; Gur, Raquel; Gur, Ruben

    2011-01-01

    Arterial spin labeling imaging (ASL) perfusion MRI is a relatively novel technique that can allow for quantitative measurement of cerebral blood flow (CBF) by using magnetically labeled arterial blood water as an endogenous tracer. Available data on resting CBF in schizophrenia primarily comes from invasive and expensive nuclear medicine techniques that are often limited to small samples and yield mixed results. The noninvasive nature of ASL offers promise for larger-scale studies. The utilit...

  1. Tub-Tag Labeling; Chemoenzymatic Incorporation of Unnatural Amino Acids.

    Science.gov (United States)

    Helma, Jonas; Leonhardt, Heinrich; Hackenberger, Christian P R; Schumacher, Dominik

    2018-01-01

    Tub-tag labeling is a chemoenzymatic method that enables the site-specific labeling of proteins. Here, the natural enzyme tubulin tyrosine ligase incorporates noncanonical tyrosine derivatives to the terminal carboxylic acid of proteins containing a 14-amino acid recognition sequence called Tub-tag. The tyrosine derivative carries a unique chemical reporter allowing for a subsequent bioorthogonal modification of proteins with a great variety of probes. Here, we describe the Tub-tag protein modification protocol in detail and explain its utilization to generate labeled proteins for advanced applications in cell biology, imaging, and diagnostics.

  2. Studies on the clinical application of MR perfusion image using arterial spin labeling method

    International Nuclear Information System (INIS)

    Miyasaka, Kenji

    1999-01-01

    A new technique for imaging brain perfusion, arterial spin labeling method was applied in clinic. Brain perfusion was imaged by FAIR and EPISTAR both of which using arterial spin labeling (ASL) method. Suitable parameters for small contamination were examined using a imaging phantom. Then normal volunteers were examined for imaging timing. Suitable time between labeling pulse and imaging pulse for brain capillary and parenchyma was 1.0 sec. For clinical application study, total 48 patients with brain diseases were examined by FAIR and/or EPISTAR. A lesion/white matter signal intensity ratio was calculated in all clinical cases. Average of signal intensity ratio in infarction, tumor and arteriovenous malformation (AVM) were 0.8, 2.2 and 18.6 at FAIR, and 0.6, 2.2 and 12.8 at EPISTAR, respectively. Low perfusion diseases such as cerebral infarction have low signal intensity ratio and high perfusion diseases such as AVM have high signal intensity ratio in both FAIR and EPISTAR. Brain lesions were imaged similarly in FAIR and EPISTAR, and no remarkable difference was found between FAIR and EPISTAR. As a result of diagnostic trial by signal intensity ratio in operated tumor, hemorrhagic cases could be diagnosed by accuracies of 75% in FAIR and 100% in EPISTAR, respectively. (author)

  3. Selective and extensive 13C labeling of a membrane protein for solid-state NMR investigations

    International Nuclear Information System (INIS)

    Hong, M.; Jakes, K.

    1999-01-01

    The selective and extensive 13C labeling of mostly hydrophobic amino acid residues in a 25 kDa membrane protein, the colicin Ia channel domain, is reported. The novel 13C labeling approach takes advantage of the amino acid biosynthetic pathways in bacteria and suppresses the synthesis of the amino acid products of the citric acid cycle. The selectivity and extensiveness of labeling significantly simplify the solid-state NMR spectra, reduce line broadening, and should permit the simultaneous measurement of multiple structural constraints. We show the assignment of most 13C resonances to specific amino acid types based on the characteristic chemical shifts, the 13C labeling pattern, and the amino acid composition of the protein. The assignment is partly confirmed by a 2D homonuclear double-quantum-filter experiment under magic-angle spinning. The high sensitivity and spectral resolution attained with this 13C-labeling protocol, which is termed TEASE for ten-amino acid selective and extensive labeling, are demonstrated

  4. Fatty acids labelled with iodine 123 or 131 in. omega. position; myocardial evolution

    Energy Technology Data Exchange (ETDEWEB)

    Riche, F.; Vidal, M. (Grenoble-1 Univ., 38 (France)); Mathieu, J.P.; Busquet, G.; Comet, M. (Grenoble-1 Univ., 38 - La Tronche (France)); Coornaert, S.; Bardy, A. (CEA Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Office des Rayonnements Ionisants); Godart, J. (Grenoble-1 Univ., 38 (France). Inst. des Sciences Nucleaires)

    A simple and rapid method of labelling a number of saturated acetylenic and Z or E ethylenic acids has been developed. The fatty acids are labelled with /sup 123/I- or /sup 131/I- in the ..omega.. position by isotopic exchange labelled NaI in acetone. Myocardial metabolism was studied by injecting the labelled fatty acids into mice.

  5. Preparation of carbon-14-labelled gallic acid

    International Nuclear Information System (INIS)

    Kozak, I.; Prochazka, M.

    1977-01-01

    Gallic acid labelled with 14 C was prepared for the needs of biological studies. A lithium derivative of trimethoxybenzene was treated with 14 CO 2 and then demethylated to yeld [carboxyl- 14 C]gallic acid. The preparation scheme and the individual steps of the synthesis are described in detail

  6. Location of the higher affinity copper site on human hemoglobin by the use of the spin label technique

    International Nuclear Information System (INIS)

    Tabak, M.; Louro, S.R.W.

    1983-11-01

    Addition of copper (II) ions to Cys β-93 maleimide spin-labelled human hemoglobin A produces a dramatic decrease in the amplitude of the spin-label ESR spectra. This effect was analyzed in the framework of Leigh's theory which permits interspin distances to be deduced from the effect of dipolar coupling on the ESR spectra and led to an estimate of 9A as the distance between the label and the higher affinity copper site. Taking into account the previous results which suggest that four nitrogen atoms coordinate with copper, and that the N terminal val β-1 and His β-2 residues are involved, the location of the higher affinity copper site is proposed to be at the β 1 β 2 interface of the hemoglobin molecule, involving the N terminal of one β subunit and the C terminal of the other. (Author) [pt

  7. Spin probes of chemistry in zeolites

    International Nuclear Information System (INIS)

    Werst, D.W.; Trifunac, A.D.

    1997-09-01

    Electron spin resonance (EPR) studies in zeolites are reviewed in which radiolysis was used to ionize the zeolite lattice, create reactive intermediates, spin label reaction products and to provide a window onto chemistry and transport of adsorbates and matrix control of chemistry. The review examines reactions of radical cations and the influence of the geometry constraints inside the zeolite, explores how zeolite model systems can be used to learn about energy and charge transfer in solids and illustrates the use of radiolysis and EPR for in situ spectroscopic studies of solid-acid catalysis. The various spin probes created inside the zeolite pores report on properties of the zeolites as well as shed light on radiolytic processes

  8. Deuterium labelling studies with unsaturated acids and nitriles

    International Nuclear Information System (INIS)

    Desai, U.V.; Mane, R.B.

    1986-01-01

    α-Deuteriated α,β-unsaturated acids have been prepared by Knoevenagel condensation of aldehydes with deuteriated malonic acid. The decarboxylation of α,β-unsaturated cyano acid with pyridine/D 2 O yields α- and γ-labelled nitriles. The deuterium incorporation is studied by pmr spectroscopy. (author). 8 refs

  9. Synthesis and distribution of L-glutamic acid with three different labels

    International Nuclear Information System (INIS)

    Cohen, M.B.; Spolter, Leonard; Chia Chin Chang; MacDonald, N.S.

    1982-01-01

    A study was performed to compare the distribution of C-11 L-glutamic acid, labeled on the carboxyl group of either the alpha or gamma carbon with that of N-13 L-glutamic acid in order to determine if the position of the label is of importance in the study of the distribution of glutamic acid

  10. Temperature-induced variation in the intrinsic hyperfine separation of a tightly bound nitroxide spin label

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, M.E.

    1979-01-01

    Recently there has been increasing interest in studying the rotational motion of biological molecules by monitoring the electron paramagnetic resonance (EPR) spectra of spin labels which are tightly bound to the molecule of interest. Theoretical studies have shown that in the slow motion region the correlation time may be determined by comparing the apparent hyperfine separation (HFS) in the presence of rotational motion with the rigid limit HFS in the absence of rotational motion. The majority of work to date has assumed the tightly bound nitroxide label to act simply as a reporter group for molecular motion, exhibiting little or no intrinsic environmental or temperature sensitivity. However, we have demonstrated that the rigid limit EPR spectra exhibit a substantial intrinsic temperature dependence, with the rigid limit HFS of MAL-6-labelled carboxyhemoglobin (HbCO) decreasing by nearly 10G over the temperature range -196/sup 0/C to +45/sup 0/C. The steepest temperature dependence was also found to occur over the 0 to 40/sup 0/C temperature range where most biological measurements are made. This strong temperature dependence in the intrinsic HFS was shown to produce substantial errors in correlation time calculations if it was not explicitly recognized and appropriate corrections made. This detailed behavior of this intrinsic temperature dependence suggests that it is most probably produced by equilibrium hydrogen bonding between the nitroxide NO/sup ./ group and an unidentified proton donor within the spin label binding site. (RJC)

  11. Early-stage differentiation between presenile Alzheimer’s disease and frontotemporal dementia using arterial spin labeling MRI

    NARCIS (Netherlands)

    R.M.E. Steketee (Rebecca); E.E. Bron (Esther); R. Meijboom (Rozanna); G.C. Houston (Gavin); S. Klein (Stefan); H.J.M.M. Mutsaerts (Henri J. M.); C. Méndez Orellana (Carolina); F.J. De Jong (Frank J.); J.C. van Swieten (John); A. van der Lugt (Aad); M. Smits (Marion)

    2016-01-01

    textabstractObjective: To investigate arterial spin labeling (ASL)-MRI for the early diagnosis of and differentiation between the two most common types of presenile dementia: Alzheimer’s disease (AD) and frontotemporal dementia (FTD), and for distinguishing age-related from pathological perfusion

  12. Early-stage differentiation between presenile Alzheimer’s disease and frontotemporal dementia using arterial spin labeling MRI

    NARCIS (Netherlands)

    R.M.E. Steketee (Rebecca); E.E. Bron (Esther); Meijboom, R. (Rozanna); Houston, G.C. (Gavin C.); Klein, S. (Stefan); H.J.M.M. Mutsaerts (Henri J. M.); Orellana, C.P.M. (Carolina P. Mendez); F.J. de Jong (Fransina); J.C. van Swieten (John); A. van der Lugt (Aad); M. Smits (Marion)

    2015-01-01

    textabstractObjective: To investigate arterial spin labeling (ASL)-MRI for the early diagnosis of and differentiation between the two most common types of presenile dementia: Alzheimer’s disease (AD) and frontotemporal dementia (FTD), and for distinguishing age-related from pathological perfusion

  13. Computing distance distributions from dipolar evolution data with overtones: RIDME spectroscopy with Gd(iii)-based spin labels.

    Science.gov (United States)

    Keller, Katharina; Mertens, Valerie; Qi, Mian; Nalepa, Anna I; Godt, Adelheid; Savitsky, Anton; Jeschke, Gunnar; Yulikov, Maxim

    2017-07-21

    Extraction of distance distributions between high-spin paramagnetic centers from relaxation induced dipolar modulation enhancement (RIDME) data is affected by the presence of overtones of dipolar frequencies. As previously proposed, we account for these overtones by using a modified kernel function in Tikhonov regularization analysis. This paper analyzes the performance of such an approach on a series of model compounds with the Gd(iii)-PyMTA complex serving as paramagnetic high-spin label. We describe the calibration of the overtone coefficients for the RIDME kernel, demonstrate the accuracy of distance distributions obtained with this approach, and show that for our series of Gd-rulers RIDME technique provides more accurate distance distributions than Gd(iii)-Gd(iii) double electron-electron resonance (DEER). The analysis of RIDME data including harmonic overtones can be performed using the MATLAB-based program OvertoneAnalysis, which is available as open-source software from the web page of ETH Zurich. This approach opens a perspective for the routine use of the RIDME technique with high-spin labels in structural biology and structural studies of other soft matter.

  14. Dynamic nuclear polarization of membrane proteins: covalently bound spin-labels at protein–protein interfaces

    International Nuclear Information System (INIS)

    Wylie, Benjamin J.; Dzikovski, Boris G.; Pawsey, Shane; Caporini, Marc; Rosay, Melanie; Freed, Jack H.; McDermott, Ann E.

    2015-01-01

    We demonstrate that dynamic nuclear polarization of membrane proteins in lipid bilayers may be achieved using a novel polarizing agent: pairs of spin labels covalently bound to a protein of interest interacting at an intermolecular interaction surface. For gramicidin A, nitroxide tags attached to the N-terminal intermolecular interface region become proximal only when bimolecular channels forms in the membrane. We obtained signal enhancements of sixfold for the dimeric protein. The enhancement effect was comparable to that of a doubly tagged sample of gramicidin C, with intramolecular spin pairs. This approach could be a powerful and selective means for signal enhancement in membrane proteins, and for recognizing intermolecular interfaces

  15. Potentials and Challenges for Arterial Spin Labeling in Pharmacological Magnetic Resonance Imaging

    OpenAIRE

    Wang, Danny J. J.; Chen, Yufen; Fernández-Seara, María A.; Detre, John A.

    2011-01-01

    Pharmacological magnetic resonance imaging (phMRI) is increasingly being used in drug discovery and development to speed the translation from the laboratory to the clinic. The two primary methods in phMRI include blood-oxygen-level-dependent (BOLD) contrast and arterial spin-labeled (ASL) perfusion MRI. BOLD contrast has been widely applied in existing phMRI studies. However, because of the lack of absolute quantification and poor reproducibility over time scales longer than hours or across s...

  16. Acetylsalicylic acid and labeling of blood constituents with technetium-99m

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, Adenilson de Souza da [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Dept. de Farmacologia e Psicobiologia; Frydman, Jacques Natan Grinapel; Rocha, Vanessa Camara da; Bernardo-Filho, Mario [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Biologia Roberto Alcantara Gomes. Dept. de Biofisica e Biometria

    2005-10-15

    Acetylsalicylic acid is the drug most used an anti-inflammatory agent and for secondary prevention of thrombotic phenomenon. Drugs can modify the labeling of blood constituents with technetium-99m (99m Tc). The aim of this work was to evaluate the effect of in vitro or in vivo assays with acetylsalicylic acid on the labeling of the blood constituents with 99m Tc. In vitro assay was performed with samples of whole blood from Wistar rats incubated with acetylsalicylic acid (1.0 mg/ml) for one hour before the 99m Tc-labeling process. For in vivo assay, Wistar rats were treated with acetylsalicylic acid (1.5 mg/kg) during one hour, and the whole blood was withdrawn for the 99m Tc-labeling process. Saline was used in control groups. Data showed that the fixation of 99m Tc to the blood constituents was not significantly (p>0.05) modified in in vitro and in vivo assays with acetylsalicylic acid, at least not when the experiments were carried out with the doses normally used in human beings. (author)

  17. Reduction in cerebral perfusion after heroin administration: a resting state arterial spin labeling study.

    Directory of Open Access Journals (Sweden)

    Niklaus Denier

    Full Text Available Heroin dependence is a chronic relapsing brain disorder, characterized by the compulsion to seek and use heroin. Heroin itself has a strong potential to produce subjective experiences characterized by intense euphoria, relaxation and release from craving. The neurofunctional foundations of these perceived effects are not well known. In this study, we have used pharmacological magnetic resonance imaging (phMRI in 15 heroin-dependent patients from a stable heroin-assisted treatment program to observe the steady state effects of heroin (60 min after administration. Patients were scanned in a cross-over and placebo controlled design. They received an injection of their regular dose of heroin or saline (placebo before or after the scan. As phMRI method, we used a pulsed arterial spin labeling (ASL sequence based on a flow-sensitive alternating inversion recovery (FAIR spin labeling scheme combined with a single-shot 3D GRASE (gradient-spin echo readout on a 3 Tesla scanner. Analysis was performed with Statistical Parametric Mapping (SPM 8, using a general linear model for whole brain comparison between the heroin and placebo conditions. We found that compared to placebo, heroin was associated with reduced perfusion in the left anterior cingulate cortex (ACC, the left medial prefrontal cortex (mPFC and in the insula (both hemispheres. Analysis of extracted perfusion values indicate strong effect sizes and no gender related differences. Reduced perfusion in these brain areas may indicate self- and emotional regulation effects of heroin in maintenance treatment.

  18. Asymmetric synthesis including enzymatic catalysis of 11C and 13N labelled amino acids

    International Nuclear Information System (INIS)

    Langstrom, B.; Antonio, G.; Bjurling, P.; Fasth, K.J.; Westerberg, G.; Watanabe, Y.

    1993-01-01

    Use of asymmetric synthesis in production of 11 C- and 13 N-labelled amino acids has been shown to be a useful approach in order to prepare amino acids routinely for PET-studies. Such PET-studies are focused either on problems related to amino acid transport, protein synthesis rate or the turnover of neurotransmitters from amino acids. The paper discusses matters regarding synthetic strategies and techniques involving production of precursors, labelled intermediates and main reaction sequences. In synthesis using the short-lived β + -emitters like 11 C and 13 N with T 1/2 of 20.3 and 10.0 min respectively, many special aspects have to be considered. The use of enzymes as catalysts has shown to be a useful tool in such preparations. The design of the labelled amino acids especially considering the stereochemistry, the position of the label will be addressed since these points are important both with regard to the application of the labelled amino acids as well as to the synthesis itself. In this presentation of the synthesis of labelled amino acids these various aspects are discussed

  19. Transport of C-13-labelled linoleic and C-13-labelled caprylic acid in rat plasma after administration of specific structured triacylglycerols

    DEFF Research Database (Denmark)

    Vistisen, Bodil; Høy, Carl-Erik

    2004-01-01

    the transport of dietary C-13-labelled fatty acids in rat plasma to compare the chylomicron fatty acid metabolism after administration of specific structured, long chain and medium chain triacylglycerols. Rats were fed ML*M, M*LM*, L*L*L* or M*M*M* (L=linoleic acid, 18:2n-6, M=caprylic acid, 8:0, * = C-13......-labelled fatty acid) by gavage. A maximum transport of 0.5% of the administered C-13-labelled 18:2n-6 was observed in 1mL rat plasma both after administration of L*L*L* and ML*M, while approximately 0.04% of the administered C-13-labelled 8:0 was detected in 1mL plasma following administration of M......*M*M* or M*LM*. After L*L*L* administration C-13-labelled 20:4n-6 was observed in plasma, probably formed by elongation and desaturation of 18:2n-6 in the enterocyte or liver cells. Furthermore, C-13-labelled 16:0, 48:0, 18: 1n-9 and 20:4n-6 were observed in plasma of rats fed M*M*M* and M*LM* due...

  20. Synthesis of specifically 2H-labeled reserpines, 3,4,5-trimethoxybenzoic acids, and syringic acid

    International Nuclear Information System (INIS)

    Roth, R.W.; Fischer, D.L.; Pachta, J.M.; Althaus, J.F.

    1982-01-01

    3,4,5-Trimethoxy- 2 H 9 -, 4-methoxy-3,5-dimethoxy- 2 H 6 , and 4-hydroxyl-3,5-dimethoxy- 2 H 6 -benzoic acids were prepared from n-propyl 3,4,5-trihydroxybenzoate (n-propyl gallate) by means of appropriate alkylation-hydrolysis sequences employing iodomethane- 2 H 3 or dimethyl- 2 H 6 -sulfate as the deuterium source. 4-Methoxy- 2 H 3 -3,5-dimethoxybenzoic acid was similarly prepared from ethyl 4-hydroxy-3,5-dimethoxybenzoate. The labeled trimethoxybenzoic acids were converted to the corresponding 2 H-labeled reserpines by condensation of the acid chlorides with methyl reserpate in pyridine according to the classical procedure. The labeled reserpine analog methyl 18-0-(4-hydroxy-3,5-dimethoxy- 2 H 6 )benzoyl reserpate was likewise prepared from 4-hydroxy-3,5-dimethoxy- 2 H 6 -benzoic acid via the intermediate methyl 18-0-(4-ethoxycarbonyloxy-3,5-dimethoxy- 2 H 6 -benzoyl)reserpate (syrosingopine- 2 H 6 ). The isotopic purity of each compound exceeded 99 atom percent 2 H. (author)

  1. Ion Channel Conformation and Oligomerization Assessment by Site-Directed Spin Labeling and Pulsed-EPR.

    Science.gov (United States)

    Pliotas, Christos

    2017-01-01

    Mechanosensitive (MS) ion channels are multimeric integral membrane proteins that respond to increased lipid bilayer tension by opening their nonselective pores to release solutes and relieve increased cytoplasmic pressure. These systems undergo major conformational changes during gating and the elucidation of their mechanism requires a deep understanding of the interplay between lipids and proteins. Lipids are responsible for transmitting lateral tension to MS channels and therefore play a key role in obtaining a molecular-detail model for mechanosensation. Site-directed spin labeling combined with electron paramagnetic resonance (EPR) spectroscopy is a powerful spectroscopic tool in the study of proteins. The main bottleneck for its use relates to challenges associated with successful isolation of the protein of interest, introduction of paramagnetic labels on desired sites, and access to specialized instrumentation and expertise. The design of sophisticated experiments, which combine a variety of existing EPR methodologies to address a diversity of specific questions, require knowledge of the limitations and strengths, characteristic of each particular EPR method. This chapter is using the MS ion channels as paradigms and focuses on the application of different EPR techniques to ion channels, in order to investigate oligomerization, conformation, and the effect of lipids on their regulation. The methodology we followed, from the initial strategic selection of mutants and sample preparation, including protein purification, spin labeling, reconstitution into lipid mimics to the complete set-up of the pulsed-EPR experiments, is described in detail. © 2017 Elsevier Inc. All rights reserved.

  2. Analysis of fluorescently labeled glycosphingolipid-derived oligosaccharides following ceramide glycanase digestion and anthranilic acid labeling.

    Science.gov (United States)

    Neville, David C A; Coquard, Virginie; Priestman, David A; te Vruchte, Danielle J M; Sillence, Daniel J; Dwek, Raymond A; Platt, Frances M; Butters, Terry D

    2004-08-15

    Interest in cellular glycosphingolipid (GSL) function has necessitated the development of a rapid and sensitive method to both analyze and characterize the full complement of structures present in various cells and tissues. An optimized method to characterize oligosaccharides released from glycosphingolipids following ceramide glycanase digestion has been developed. The procedure uses the fluorescent compound anthranilic acid (2-aminobenzoic acid; 2-AA) to label oligosaccharides prior to analysis using normal-phase high-performance liquid chromatography. The labeling procedure is rapid, selective, and easy to perform and is based on the published method of Anumula and Dhume [Glycobiology 8 (1998) 685], originally used to analyze N-linked oligosaccharides. It is less time consuming than a previously published 2-aminobenzamide labeling method [Anal. Biochem. 298 (2001) 207] for analyzing GSL-derived oligosaccharides, as the fluorescent labeling is performed on the enzyme reaction mixture. The purification of 2-AA-labeled products has been improved to ensure recovery of oligosaccharides containing one to four monosaccharide units, which was not previously possible using the Anumula and Dhume post-derivatization purification procedure. This new approach may also be used to analyze both N- and O-linked oligosaccharides.

  3. In the search for new anticancer drugs XII. Synthesis and biological evaluation of spin labeled nitrosoureas.

    Science.gov (United States)

    Sosnovsky, G; Li, S W

    1985-04-15

    The spin labeled nitrosourea 1-(2-chloroethyl)-3-(1-oxyl-2,2,6,6- tetramethyl-piperidinyl)-1-nitrosourea (SLCNU, 4) and its analogues 5-7 were synthesized either by a regio-selective method or by a conventional route via the nitrosation of the spin labeled intermediates (11a-e). Nitrosation of the ureas 11a-e with dinitrogen tetraoxide resulted in better yields than those obtained with sodium nitrite. The nitrosoureas 4-8 were tested for their anticancer activity against the lymphocytic leukemia P388 in mice. Thus, either at the equal molar dose or at the dose of equal toxicity level, the SLCNU (4) was found to be more active than the clinically used CCNU (1). Unlike CCNU (1) whose LD50 is 56 mg/kg, the SLCNU (4) possesses a low toxicity (LD50 123 mg/kg). Therefore, SLCNU (4) is a promising new entry into the nitrosourea class of anticancer drugs.

  4. A magnetic resonance study of the segmental motion and local conformations of poly-(L-glutamic acid) in aqueous solutions

    International Nuclear Information System (INIS)

    Tsutsumi, Akihiro; Perly, Bruno; Forchioni, Alain; Chachaty, Claude.

    1978-01-01

    A study was made on: ESR of spin labeled poly (L-glutamic acid) (PLGA); proton chemical shifts and vicinal coupling constants; pH dependences of proton and deuteron relaxations; proton relaxation enhancement in spin labeled PLGA; proton and carbon 13 relaxations in neutral solutions

  5. In vitro comparison of HMPAO and gentisic acid for labelling leukocytes with 99mTc

    International Nuclear Information System (INIS)

    Ecclestone, M.; Proulx, A.; Ballinger, J.R.; Gerson, B.; Reid, R.H.; Gulenchyn, K.Y.

    1990-01-01

    Leukocytes can be labelled with 99m Tc using HMPAO and gentisic acid methods. We compared the two methods with respect to labelling efficiency on mixed leukocytes and isolated polymorphonuclear (PMN) and mononuclear (MN) cells, and the in vitro stability of the label. HMPAO produced approximately 70% labelling efficiency on mixed or PMN cells and the label was stable in saline or plasma. Labelling efficiency on MN was only 14% and was less stable. Gentisic acid produced a labelling efficiency of 52% on PMN and 35% on MN; both were stable in saline but less stable in plasma. In conclusion, HMPAO produces higher labelling efficiency and the label shows greater in vitro stability in plasma. However, gentistic acid is much less expensive to use, allows labelling of MN cells, and should result in more favourable microdosimetry. Preliminary clinical results suggest that gentistic acid is equivalent to HMPAO but has the advantage of being much cheaper. (orig.)

  6. Arterial Transit Time-corrected Renal Blood Flow Measurement with Pulsed Continuous Arterial Spin Labeling MR Imaging.

    Science.gov (United States)

    Shimizu, Kazuhiro; Kosaka, Nobuyuki; Fujiwara, Yasuhiro; Matsuda, Tsuyoshi; Yamamoto, Tatsuya; Tsuchida, Tatsuro; Tsuchiyama, Katsuki; Oyama, Nobuyuki; Kimura, Hirohiko

    2017-01-10

    The importance of arterial transit time (ATT) correction for arterial spin labeling MRI has been well debated in neuroimaging, but it has not been well evaluated in renal imaging. The purpose of this study was to evaluate the feasibility of pulsed continuous arterial spin labeling (pcASL) MRI with multiple post-labeling delay (PLD) acquisition for measuring ATT-corrected renal blood flow (ATC-RBF). A total of 14 volunteers were categorized into younger (n = 8; mean age, 27.0 years) and older groups (n = 6; 64.8 years). Images of pcASL were obtained at three different PLDs (0.5, 1.0, and 1.5 s), and ATC-RBF and ATT were calculated using a single-compartment model. To validate ATC-RBF, a comparative study of effective renal plasma flow (ERPF) measured by 99m Tc-MAG3 scintigraphy was performed. ATC-RBF was corrected by kidney volume (ATC-cRBF) for comparison with ERPF. The younger group showed significantly higher ATC-RBF (157.68 ± 38.37 mL/min/100 g) and shorter ATT (961.33 ± 260.87 ms) than the older group (117.42 ± 24.03 mL/min/100 g and 1227.94 ± 226.51 ms, respectively; P renal ASL-MRI as debated in brain imaging.

  7. Molecular order and T1-relaxation, cross-relaxation in nitroxide spin labels

    Science.gov (United States)

    Marsh, Derek

    2018-05-01

    Interpretation of saturation-recovery EPR experiments on nitroxide spin labels whose angular rotation is restricted by the orienting potential of the environment (e.g., membranes) currently concentrates on the influence of rotational rates and not of molecular order. Here, I consider the dependence on molecular ordering of contributions to the rates of electron spin-lattice relaxation and cross relaxation from modulation of N-hyperfine and Zeeman anisotropies. These are determined by the averages and , where θ is the angle between the nitroxide z-axis and the static magnetic field, which in turn depends on the angles that these two directions make with the director of uniaxial ordering. For saturation-recovery EPR at 9 GHz, the recovery rate constant is predicted to decrease with increasing order for the magnetic field oriented parallel to the director, and to increase slightly for the perpendicular field orientation. The latter situation corresponds to the usual experimental protocol and is consistent with the dependence on chain-labelling position in lipid bilayer membranes. An altered dependence on order parameter is predicted for saturation-recovery EPR at high field (94 GHz) that is not entirely consistent with observation. Comparisons with experiment are complicated by contributions from slow-motional components, and an unexplained background recovery rate that most probably is independent of order parameter. In general, this analysis supports the interpretation that recovery rates are determined principally by rotational diffusion rates, but experiments at other spectral positions/field orientations could increase the sensitivity to order parameter.

  8. Hydrophilic interaction liquid chromatography of anthranilic acid-labelled oligosaccharides with a 4-aminobenzoic acid ethyl ester-labelled dextran hydrolysate internal standard.

    Science.gov (United States)

    Neville, David C A; Alonzi, Dominic S; Butters, Terry D

    2012-04-13

    Hydrophilic interaction liquid chromatography (HILIC) of fluorescently labelled oligosaccharides is used in many laboratories to analyse complex oligosaccharide mixtures. Separations are routinely performed using a TSK gel-Amide 80 HPLC column, and retention times of different oligosaccharide species are converted to glucose unit (GU) values that are determined with reference to an external standard. However, if retention times were to be compared with an internal standard, consistent and more accurate GU values would be obtained. We present a method to perform internal standard-calibrated HILIC of fluorescently labelled oligosaccharides. The method relies on co-injection of 4-aminobenzoic acid ethyl ester (4-ABEE)-labelled internal standard and detection by UV absorption, with 2-AA (2-aminobenzoic acid)-labelled oligosaccharides. 4-ABEE is a UV chromophore and a fluorophore, but there is no overlap of the fluorescent spectrum of 4-ABEE with the commonly used fluorescent reagents. The dual nature of 4-ABEE allows for accurate calculation of the delay between UV and fluorescent signals when determining the GU values of individual oligosaccharides. The GU values obtained are inherently more accurate as slight differences in gradients that can influence retention are negated by use of an internal standard. Therefore, this paper provides the first method for determination of HPLC-derived GU values of fluorescently labelled oligosaccharides using an internal calibrant. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Spin Label Studies of the Hemoglobin-Membrane Interaction During Sickle Hemoglobin Polymerization

    International Nuclear Information System (INIS)

    Falcon Dieguez, Jose E.; Rodi, Pablo; Lores Guevara, Manuel A.; Gennaro, Ana Maria

    2009-12-01

    An enhanced hemoglobin-membrane association has been previously documented in Sickle Cell Anemia. However, it is not known how this interaction is modified during the hemoglobin S polymerization process. In this work, we use a model of reconstituted erythrocytes from ghost membranes whose cytoskeleton proteins had been previously labeled with the 4-maleimido Tempo spin label, and that were subsequently resealed with hemoglobin S or A solutions. Using EPR spectroscopy, we studied the time dependence of the spectral W/S parameter, indicative of the conformational state of cytoskeleton proteins (mainly spectrin) under spontaneous deoxygenation, with the aim of detecting the eventual effects due to hemoglobin S polymerization. The differences observed in the temporal behaviour of W/S in erythrocytes reconstituted with both hemoglobins were considered as experimental evidence of an increment in hemoglobin S-membrane interaction, as a result of the polymerization process of hemoglobin S under spontaneous deoxygenation. (author)

  10. Interactions of the spin-labeled chloroethylnitrosourea SLCNUgly with electrode-supported lipid films

    International Nuclear Information System (INIS)

    Tacheva, Bilyana; Georgieva, Radostina; Karabaliev, Miroslav

    2016-01-01

    The spin-labeled chloroethylnitrosourea containig glycine SLCNUgly is an analogue of the clinically used nitrosourea drug lomustine (1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea, CCNU), showing promising properties and features in vitro as well as in vivo. In this work the interaction of SLCNUgly with a lipid model membrane is investigated. The presented results indicate penetration of the drug in the membranes without causing defects of the lipid structure and reveal the potential of both SLCNUgly and electrode-supported lipid films as models for investigating nitrosourea drugs-membrane interactions.

  11. Myocardial scintigraphy with I-123 labeled fatty acids

    International Nuclear Information System (INIS)

    Dudczak, R.

    1983-01-01

    This study presents experimental and clinical data in the use of I-123 labeled aromatic and aliphatic fatty acids. I-123 p-phenylpentadecanoic acid (p-IPPA) and I-123 heptadecanoic acid (HDA) were applied for myocardial scintigraphy. The feasibility of p-IPPA and HDA for myocardial scintigraphy was substantiated in animal experiments. Clinical studies were performed in patients with coronary artery disease (CAD) and cardiomyopathy (CMP). In CAD the results of fatty acid studies were compared with those of Tl-201. I-123 labeled fatty acids proved to be a useful tool for myocardial scintigraphy. The possibility to evaluate non invasively the myocardial metabolic function in man may add a complementary diagnostic tool in the clinical follow up of patients with heart disease. In CAD studies with I-123 p-IPPA and I-123 HDA might provide a means to assess the degree of myocardial viability and to identify a subgroup of patients who are at increased risk for irreversible myocardial damage. In patients with CMP it is probable that these studies may be used as a means of separating groups of patients with this disease. (Author)

  12. On the synthesis of 11C-labelled aromatic amino acids

    International Nuclear Information System (INIS)

    Halldin, C.

    1984-01-01

    The use of 11 C-labelled aromatic amino acids in positron emission tomography (PET) and their importance in physiological studies, especially cerebral protein synthesis or their role as precursors of neurotransmitters, is discussed. The synthesis of 11 -C-labelled aromatic amino acids by various routes is presented and new 11 C-labelled precursors, aromatic and aliphatic 11 C-aldehydes, are reported. The 11 C-aldehydes were obtained in 60-95% radiochemical yield and reaction times were of the order of 5 min. The 11 C-aldehydes have been used in condensation reactions with 2-aryl-5-oxazolones in the presence of a tertiary amine, diazabicyclooctane (DABCO), to produce the corresponding [α- 11 C]-4-arylene-2-aryl-5-oxazolones. Ring opening, hydrogenation and removal of protecting groups were carried out in one step to produce the racemic [3- 11 C]-labelled aromatic amino acids in 8-30% radiochemical yield. The total reaction time was 52-60 min. L-[3- 11 C]Phenylalanine was obtained by a seven-step synthesis in 80% e.e. (enantiomeric excess) and 60% e.e., respectively, in 10-15% radiochemical yield within 60 min, by use of the chiral rhodium complex of (R)-1,2-bis(diphenylphosphino)propane ((R)-PROPHOS) or (+)-2,3-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane ((+)-DIOP) in the hydrogenation reaction. Racemic [2- 11 C]-labelled aromatic amino acids were produced by a high-pressure, high-temperature modification of the Buechere-Strecker synthesis. [2- 11 C]Phenylglycine was obtained in 20% radiochemical yield within 50 min. [3- 11 C]Phenylpyruvic acid was prepared via the aldehyde-oxyzolone condensation reaction in 40% radiochemical yield within 40 min (not including LC separation). Its use in the synthesis of [3- 11 C]-phenylalanine by enzymatic transamination is also discussed. With 32 refs.(Author)

  13. Synthesis of tritium-labelled isopenicillin N, penicillin N and 6-aminopenicillanic acid

    International Nuclear Information System (INIS)

    Usher, J.J.; Loder, B.; Abraham, E.P.

    1975-01-01

    1. Phenoxymethylpenicillin sulphoxide 4-methoxybenzyl ester was labelled with 3 H in its 2-β-methyl group. Its specific radioactivity was 362mCi/mmol. 2. Removal of the side chain of this compound yielded the corresponding ester of 6-aminopenicillanic acid sulphoxide and coupling of the latter with the appropriate protected α-aminoadipic acid gave 4-methoxybenzyloxycarbonylisopenicillin N sulphoxide di-4-methoxybenzyl ester or the corresponding derivative of penicillin N. 3. Removal of the protective groups by hydrogenolysis and reduction of the sulphoxide group yielded 3 H-labelled isopenicillin N or penicillin N. 4. 3 H-labelled phenoxymethylpenicillin sulphoxide was obtained by hydrogenolysis from its 4-methoxybenzyl ester. Reducton of its sulphoxide group and subsequent removal of the side chain gave 3 H-labelled 6-aminopenicillanic acid. (author)

  14. Syntheses of [ω-11C]-labelled fatty acids using alkyl halides and Grignard reagents

    International Nuclear Information System (INIS)

    Kihlberg, T.; Malmborg, P.; Langstroem, B.

    1990-01-01

    A method for synthesizing carbon-11 labelled fatty acids, where the carbon-11 has a mid-chain location, has been developed. Fatty acids labelled thus are less susceptible to early loss of the label through metabolic degradation. Carbon-11 labelled methyl iodide was trapped in a solution of alpha, omega-di(bromo magnesium)alkane in THF. Li 2 CuCl 4 was added and allowed to react. Carbon dioxide was introduced into the mixture, followed by heating and then hydrolysis. Hexanoic, octanoic, and decanoic acids were synthesized with this method

  15. Structure and dynamics of spin-labeled insulin entrapped in a silica matrix by the sol-gel method.

    Science.gov (United States)

    Vanea, E; Gruian, C; Rickert, C; Steinhoff, H-J; Simon, V

    2013-08-12

    The structure and conformational dynamics of insulin entrapped into a silica matrix was monitored during the sol to maturated-gel transition by electron paramagnetic resonance (EPR) spectroscopy. Insulin was successfully spin-labeled with iodoacetamide and the bifunctional nitroxide reagent HO-1944. Room temperature continuous wave (cw) EPR spectra of insulin were recorded to assess the mobility of the attached spin labels. Insulin conformation and its distribution within the silica matrix were studied using double electron-electron resonance (DEER) and low-temperature cw-EPR. A porous oxide matrix seems to form around insulin molecules with pore diameters in the order of a few nanometers. Secondary structure of the encapsulated insulin investigated by Fourier transform infrared spectroscopy proved a high structural integrity of insulin even in the dried silica matrix. The results show that silica encapsulation can be used as a powerful tool to effectively isolate and functionally preserve biomolecules during preparation, storage, and release.

  16. Labeling of monoclonal antibodies with a 67Ga-phenolic aminocarboxylic acid chelate. Part I. Chemistry and labeling technique.

    Science.gov (United States)

    Schuhmacher, J; Matys, R; Hauser, H; Maier-Borst, W; Matzku, S

    1986-01-01

    As a chelating agent for labeling antibodies (Abs) with metallic radionuclides, a propionic acid substituted ethylenediamine N,N'-di-[(o-hydroxyphenyl) acetic acid] (P-EDDHA), which tightly complexes 67Ga, was synthesized. The 67Ga-P-EDDHA chelate was coupled in aqueous solution to IgG at a molar ratio of 1:1 via carbodiimide. The average coupling yield was 15%. A specific activity of 4 mCi/mg IgG could be obtained with commercially supplied 67Ga. In vitro stability was evaluated in human serum at 37 degrees C and showed a half-life of about 120 h for the release of 67Ga from the labeled Ab during the initial phase of incubation. This in vitro halflife is similar to that measured for 111In-DTPA labeled Abs. Because of the high stability of the 67Ga-P-EDDHA chelate, the in vivo formation of radioactive labeled transferrin by transchelation, as described for 111In-DTPA labeled Abs, should, however, be reduced by this labeling technique.

  17. Palmitic acid-labeled lipids selectively incorporated into platelet cytoskeleton during aggregation

    International Nuclear Information System (INIS)

    Packham, M.A.; Guccione, M.A.; Bryant, N.L.; Livne, A.

    1990-01-01

    Previous experiments showed that during the early stages (20-30 seconds) of aggregation induced by adenosine diphosphate (ADP, 2 microM) or thrombin (0.1 U/mL) of rabbit or human platelets prelabeled with [3H]palmitic acid, labeled lipid became associated with the cytoskeleton isolated after lysis with 1% Triton X-100, 5 mM EGTA [ethylene glycol-bis-(beta-aminoethyl ether)]-N,N,N',N'-tetra-acetic acid. The association appeared to be related to the number of sites of contact and was independent of the release of granule contents. We have now investigated the nature of the labeled lipids by thin-layer and column chromatography and found differences between the distribution of the label in intact platelets (both stimulated and unstimulated) and the isolated cytoskeletons. In both species, and with either ADP or thrombin as aggregating agent, 70-85% of the label in both intact platelets and in the cytoskeletons was in phospholipids. The distribution of label among the phospholipids in the cytoskeletons was similar to that in intact platelets except that the percentage of label in phosphatidylcholine was significantly higher in the cytoskeletons of human platelets than in the intact platelets, and the percentage of label in phosphatidylserine/phosphatidylinositol was significantly lower in the cytoskeletons of rabbit platelets and thrombin-aggregated human platelets than in intact platelets. The cytoskeletons contained a lower percentage of label in triacylglycerol, diacylglycerol, and cholesterol ester than the intact platelets. Contrary to a report in the literature, we found no evidence for the incorporation of diacylglycerol and palmitic acid into the cytoskeleton

  18. Understanding the mechanism of sweet taste: synthesis of tritium labeled guanidineacetic acids

    Energy Technology Data Exchange (ETDEWEB)

    Nagarajan, S.; Kellogg, M.S.; DuBois, G.E. (NutraSweet Company, Mt. Prospect, IL (United States)); Williams, D.S. (Amersham International plc, Cardiff (United Kingdom). Cardiff Labs.); Gresk, C.J.; Markos, C.S. (Searle Research and Development, Skokie, IL (United States))

    1992-08-01

    Syntheses of tritium labeled guanidineacetic acid sweetener and a tritiated photoaffinity labeling reagent via the catalytic hydrogenation of the dibromo intermediates are described. These labeled compounds were required for the investigation of sweet taste mechanism. (author).

  19. Understanding the mechanism of sweet taste: synthesis of tritium labeled guanidineacetic acids

    International Nuclear Information System (INIS)

    Nagarajan, S.; Kellogg, M.S.; DuBois, G.E.; Williams, D.S.

    1992-01-01

    Syntheses of tritium labeled guanidineacetic acid sweetener and a tritiated photoaffinity labeling reagent via the catalytic hydrogenation of the dibromo intermediates are described. These labeled compounds were required for the investigation of sweet taste mechanism. (author)

  20. The preparation of 32P labelled phosphorous acid

    International Nuclear Information System (INIS)

    Henderson, D.; Jenkinson, A.; Sorby, P.

    1986-11-01

    Phosphorous acid labelled with 32 P has been prepared, on a small scale, starting from neutron-irradiated phosphorus. The compound is intended for tracer studies in the development of novel fungicides

  1. All-atom molecular dynamics simulations of spin labelled double and single-strand DNA for EPR studies.

    Science.gov (United States)

    Prior, C; Danilāne, L; Oganesyan, V S

    2018-05-16

    We report the first application of fully atomistic molecular dynamics (MD) simulations to the prediction of electron paramagnetic resonance (EPR) spectra of spin labelled DNA. Models for two structurally different DNA spin probes with either the rigid or flexible position of the nitroxide group in the base pair, employed in experimental studies previously, have been developed. By the application of the combined MD-EPR simulation methodology we aimed at the following. Firstly, to provide a test bed against a sensitive spectroscopic technique for the recently developed improved version of the parmbsc1 force field for MD modelling of DNA. The predicted EPR spectra show good agreement with the experimental ones available from the literature, thus confirming the accuracy of the currently employed DNA force fields. Secondly, to provide a quantitative interpretation of the motional contributions into the dynamics of spin probes in both duplex and single-strand DNA fragments and to analyse their perturbing effects on the local DNA structure. Finally, a combination of MD and EPR allowed us to test the validity of the application of the Model-Free (M-F) approach coupled with the partial averaging of magnetic tensors to the simulation of EPR spectra of DNA systems by comparing the resultant EPR spectra with those simulated directly from MD trajectories. The advantage of the M-F based EPR simulation approach over the direct propagation techniques is that it requires motional and order parameters that can be calculated from shorter MD trajectories. The reported MD-EPR methodology is transferable to the prediction and interpretation of EPR spectra of higher order DNA structures with novel types of spin labels.

  2. SMALL SCALE PREPARATION OF C14 LABELED SUCCINIC, MALIC, FUMARICAND TARTARIC ACIDS

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, E.C.; Bassham, J.A.; Calvin, M.; Tolbert, B.M.

    1951-06-12

    The directions for preparing the following acids from labeled acetic acid on a 1 to 20 millimole scale is presented: Succinic acid, malic acid, fumaric acid and tartaric acid. Two methods for preparing the succinic acid are detailed.

  3. Formamidine sulfinic acid as reducing agent in technetium-99m rhenium sulfide labelling

    Energy Technology Data Exchange (ETDEWEB)

    Neves, M; Patricio, L [Laboratorio Nacional de Engenharia e Technologia Industrial, Sacavem (Portugal). Dept. de Radioisotopes; Ferronha, H [Laboratorio Nacional de Investigacao Veterinaria, Lisboa (Portugal)

    1989-08-01

    Labelling kinetic studies, radiochemical characterization and particle size evaluation of {sup 99m}Tc rhenium sulfide colloid using formamidine sulfinic acid as reducing agent are described. Comparison with the same colloid which makes use of Sn-sodium pyrophosphate complex as reducing agent showed higher labelling yields, simplification of labelling procedure and a longer shelf life when formamidine sulfinic acid was used. (author) 15 refs.; 7 figs.

  4. A Short Introduction to Arterial Spin Labeling and its Application to Flow Territory Mapping.

    Science.gov (United States)

    Lindner, T; Helle, M; Jansen, O

    2015-10-01

    Arterial spin labeling (ASL) is an emerging method for the assessment of perfusion in various diseases of the brain. In ASL, the magnetization of arterial blood water spins is manipulated in a complete non-invasive way before flowing into the tissue of interest. This allows absolute quantification of cerebral blood flow, thereby, presenting an alternative to contrast-enhanced methods based on computed tomography or magnetic resonance imaging. Furthermore, its potential application for flow territory mapping can provide additional information of the individual configuration of intracerebral blood flow. This article gives a brief overview of the basic ASL methodology and its approaches to image individual perfusion territories. Additionally, the utilization of ASL in a variety of cerebrovascular diseases is presented to provide examples of potential applications of (territorial) ASL in clinical routine.

  5. Measurement of the metabolic interconversion of deuterium-labeled fatty acids by gas chromatography/mass spectrometry

    International Nuclear Information System (INIS)

    Rohwedder, W.K.; Duval, S.M.; Wolf, D.J.; Emken, E.A.

    1990-01-01

    An analytical method that was developed to analyze deuterium-labeled fatty acids in human blood has been extended to identify labeled fatty acids from C14 to C24 chain length which are formed by metabolic processes such as desaturation, elongation, or shortening of the labeled fatty acids fed. A new computer and a hardware adder have been utilized to assure reliable data acquisition. Relative standard deviations for the analysis of labeled fatty acids were measured at 0.02, 0.03, and 0.04 at the 5%, 1%, and 0.2% levels of the labeled fatty acid methyl esters, respectively. The method makes extensive use of standards and computer processing for accuracy and high productivity. Data from a chylomicron triacylglycerol fraction are included to demonstrate the sensitivity of detection of metabolites formed by desaturation and elongation

  6. Computer-assisted high-pressure liquid chromatography of radio-labelled phenylthiohydantoin amino acids

    International Nuclear Information System (INIS)

    Bhown, A.S.; Mole, J.E.; Hollaway, W.L.; Bennet, J.C.

    1978-01-01

    A computer-controlled high-pressure liquid chromatographic (HPLC) system is described to identify in vitro phenyl [ 35 S]isothiocyanate-labelled phenylthiohydantoin (PTH) amino acids from a solid-phase sequencer. Each radio-labelled amino acid from the sequencer is added to a PTH amino acid standard and the mixture separated by HPLC using a computer, programmed to detect a slope change in the absorbance. Individual fractions corresponding to the PTH amino acids are collected and counted. The sensitivity of the system is demonstrated on 700 pmoles of lysozyme. (Auth.)

  7. Radiochemically pure [1-14C]valproic acid--a mixture of labeled structural isomers

    International Nuclear Information System (INIS)

    Dickinson, R.G.; Wood, B.T.; Kluck, R.M.; Hooper, W.D.

    1986-01-01

    Ongoing studies of the disposition of valproic acid (VPA) and its glucuronide conjugate required the radiolabeled drug for greater sensitivity and tracing of oxidation metabolites. [1- 14 C]VPA hereinafter called LABEL (radiochemical purity greater than 98% as determined by paper and thin layer chromatography) was purchased from Amersham International, U.K. Quantitative analysis of VPA and VPA-glucuronide in bile and urine samples from rats given VPA and tracer LABEL by our standard gas chromatographic assay showed gross discrepancies with the results obtained by liquid scintillation counting of the same extracts. Examination of the purity of LABEL was therefore undertaken. Equilibration of LABEL between various organic-aqueous solvent pairs was identical to that of authentic VPA. However, gas chromatographic-mass spectrometric analysis of the trimethylsilyl derivative of LABEL revealed it to be a mixture of labeled 2-methylheptanoic acid (approximately 60%), 2-ethylhexanoic acid (approximately 30%), and 2-propylpentanoic acid (i.e., VPA, 5-10%). The origin of the isomers of VPA in LABEL was logically traced to the synthetic procedure--coupling of the Grignard reagent of (an isomeric mixture of 2-, 3-, and 4-) chloroheptane(s) with [ 14 C]carbon dioxide. This result highlights the inadequacy of the quality control procedures used and reinforces the necessity for caution in accepting the quoted purity of radiolabeled drugs

  8. Biosynthesis of gallic and ellagic acids with 14C-labeled compounds in Acer and Rhus leaves

    International Nuclear Information System (INIS)

    Ishikura, Nariyuki; Hayashida, Shunzo; Tazaki, Kiyoshi

    1984-01-01

    The biosynthetic pathway for gallic and ellagic acids in young, mature and autumn leaves of Acer buergerianum and Rhus succedanea was examined by tracer experiments, and also by isotope competition, with D-shikimic acid- 14 C, L-phenylalanine-U- 14 C, L-phenyllactic acid-U- 14 C, gallic acid-G- 14 C and their unlabeled compounds. In young leaves of both plants, the incorporation rate of labeled shikimic acid into gallic acid was significantly higher than that of labeled phenylalanine, whereas in the mature and autumn leaves the latter was a good precursor rather than the former for the gallic acid biosynthesis. Therefore, two pathways for gallic acid formation, through β-oxidation of phenylpropanoid and through dehydrogenation of shikimic acid, could be operating in Acer and Rhus leaves, and the preferential pathway is altered by leaf age. In both plants, the incorporation rate of labeled phenyllactic acid during a 24 hr metabolic period was almost the same as that of labeled phenylalanine. The incorporation of D-shikimic acid-G- 14 C, L-phenylalanine-U- 14 C and L-phenyllactic acid-U- 14 C into ellagic acid was very similar to the case of the radioactive gallic acid formation. Furthermore, regardless of the presence of unlabeled shikimic acid and/or phenylalanine, incorporation of the radioactivity of labeled gallic acid into ellagic acid occurred at a very high rate, suggesting the reciprocal radical reaction of gallic acid for the ellagic acid formation. The incorporation of labeled compounds into ellagitannins was also examined and their biosynthesis discussed further. (author)

  9. Study of the biogenesis of flavones and cinnamic acids by using molecules labelled with carbon 14

    International Nuclear Information System (INIS)

    Chabannes, Bernard

    1970-01-01

    This research thesis reports the study of flavones, flavonoid compounds and cinnamic acids which are very common as natural pigments in plant species. The author first reports the study of the synthesis of shikimic acid labelled with carbon 14 (biological methods of preparation, synthesis), and then the synthesis of prunin labelled with carbon 14. The next part reports the study of the transformation of prunin labelled with carbon 14 into cosmosiine in flowers with white cosmos. The author finally compares the introduction of cinnamic acid and of shikimic acid (both labelled with carbon 14) into the sinapic acid of red cabbage leaves

  10. Spin trapping study on the nature of radicals generated by X radiolysis and peroxidation of linolenic acid

    International Nuclear Information System (INIS)

    Azizova, O.A.; Osipov, A.N.; Zubarev, V.E.; Yakhyaev, A.V.; Vladimirov, Yu.A.; Savov, V.M.; Kagan, V.E.

    1983-01-01

    The radicals of linolenic acid and their spin adducts (SA) with PBN formed during X radiolysis of linolenic acid and in lipid peroxidation with ferrous ions were investigated and identified. It was found that in the absence of oxygen in pure linolenic acid at 77 K X irradiation produces alkyl and carboxyl radicals. In the presence of the spin trap alkyl radical spin adducts were formed. Irradiation of linolenic acid in the presence of oxygen at 77 K also resulted in the formation of alkyl radicals. These radicals were transformed into peroxy radicals in the interaction of alkyl radical with oxygen upon heating to 117 K. In the presence of spin trap X irradiation of linolenic acid and heating of the sample up to 300 K gave rise to EPR spectra of SA alkyl and unidentified radicals. Lipid peroxidation of linolenic acid induced by ferrous ions in the presence of spin trap also formed radicals and SA of linolenic acid. The spectral parameters of SA generated with ferrous ions in lipid peroxidation and of those generated during X radiolysis do not differ. The similarity of spectral parameters of SA in these two cases suggests a similarity in the structure of linolenic acid radicals. (author)

  11. Subcellular SIMS imaging of isotopically labeled amino acids in cryogenically prepared cells

    International Nuclear Information System (INIS)

    Chandra, Subhash

    2004-01-01

    Ion microscopy is a potentially powerful technique for localization of isotopically labeled molecules. In this study, L-arginine and phenylalanine amino acids labeled with stable isotopes 13 C and 15 N were localized in cultured cells with the ion microscope at 500 nm spatial resolution. Cells were exposed to the labeled amino acids and cryogenically prepared. SIMS analyses were made in fractured freeze-dried cells. A dynamic distribution was observed from labeled arginine-treated LLC-PK 1 kidney cells at mass 28 ( 13 C 15 N) in negative secondaries, revealing cell-to-cell heterogeneity and preferential accumulation of the amino acid (or its metabolite) in the nucleus and nucleolus of some cells. The smaller nucleolus inside the nucleus was clearly resolved in SIMS images and confirmed by correlative light microscopy. The distribution of labeled phenylalanine contrasted with arginine as it was rather homogeneously distributed in T98G human glioblastoma cells. Images of 39 K, 23 Na and 40 Ca were also recorded to confirm the reliability of sample preparation and authenticity of the observed amino acid distributions. These observations indicate that SIMS techniques can provide a valuable technology for subcellular localization of nitrogen-containing molecules in proteomics since nitrogen does not have a radionuclide tracer isotope. Amino acids labeled with stable isotopes can be used as tracers for studying their transport and metabolism in distinct subcellular compartments with SIMS. Further studies of phenylalanine uptake in human glioblastoma cells may have special significance in boron neutron capture therapy (BNCT) as a boron analogue of phenylalanine, boronophenylalanine is a clinically approved compound for the treatment of brain tumors

  12. Subcellular SIMS imaging of isotopically labeled amino acids in cryogenically prepared cells

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, Subhash

    2004-06-15

    Ion microscopy is a potentially powerful technique for localization of isotopically labeled molecules. In this study, L-arginine and phenylalanine amino acids labeled with stable isotopes {sup 13}C and {sup 15}N were localized in cultured cells with the ion microscope at 500 nm spatial resolution. Cells were exposed to the labeled amino acids and cryogenically prepared. SIMS analyses were made in fractured freeze-dried cells. A dynamic distribution was observed from labeled arginine-treated LLC-PK{sub 1} kidney cells at mass 28 ({sup 13}C{sup 15}N) in negative secondaries, revealing cell-to-cell heterogeneity and preferential accumulation of the amino acid (or its metabolite) in the nucleus and nucleolus of some cells. The smaller nucleolus inside the nucleus was clearly resolved in SIMS images and confirmed by correlative light microscopy. The distribution of labeled phenylalanine contrasted with arginine as it was rather homogeneously distributed in T98G human glioblastoma cells. Images of {sup 39}K, {sup 23}Na and {sup 40}Ca were also recorded to confirm the reliability of sample preparation and authenticity of the observed amino acid distributions. These observations indicate that SIMS techniques can provide a valuable technology for subcellular localization of nitrogen-containing molecules in proteomics since nitrogen does not have a radionuclide tracer isotope. Amino acids labeled with stable isotopes can be used as tracers for studying their transport and metabolism in distinct subcellular compartments with SIMS. Further studies of phenylalanine uptake in human glioblastoma cells may have special significance in boron neutron capture therapy (BNCT) as a boron analogue of phenylalanine, boronophenylalanine is a clinically approved compound for the treatment of brain tumors.

  13. Ligand exchange chromatography for analysis and preparative separation of tritium-labelled amino acids

    International Nuclear Information System (INIS)

    Zolotarev, Yu.A.; Zaitsev, D.A.; Penkina, V.I.; Dostavalov, I.N.; Myasoedov, N.F.

    1988-01-01

    Racemic tritium-labelled amino acids were separated into optical isomers by chromatography on a chiral polyacrylamide sorbent filled with copper ions. The polyacrylamide sorbent is synthesized by Mannich's reaction through the action of formaldehyde and L-phenylalanine upon polyacrylamide Biogel P-4 in an alkali phosphate buffer. Tritium-labelled amino acids are eluted by a weak alkali solution of ammonium carbonate. Data are presented on the ligand exchange chromatography of amino acids depending on the degree to which the sorbent is filled with copper ions and on the eluent concentration. Amino acids are isolated from the eluent on short columns filled with sulfonated cation exchanger in the H + form. HPLC on modified silica gel sorbents is also used for the analysis of tritium-labelled optically active amino acids. Amino acids are eluted by a weakly acidic water-methanol solution containing ammonium acetate. UV and scintillation flow type detectors are used. (author) 7 refs.; 8 figs

  14. Labeling of antibodies with a /sup 67/Ga-phenolic aminocarboxylic acid chelate. Pt. 1. Chemistry and labeling technique

    Energy Technology Data Exchange (ETDEWEB)

    Schuhmacher, J.; Matys, R.; Hauser, H.; Maier-Borst, W.; Matzku, S.

    1986-11-01

    As a chelating agent for labeling antibodies (Abs) with metallic radionuclides, a propionic acid substituted ethylenediamine N, N'-di-((o-hydroxyphenyl) acetic acid) (P-EDDHA), which tighly complexes /sup 67/Ga, was synthetized. The /sup 67/Ga-P-EDDHA chelate was coupled in aqueous solution to IgG at a molar ratio of 1:1 via carbodiimide. The average coupling yield was 15%. A specific activity of 4 mCi/mg IgG could be obtained with commercially supplied /sup 67/Ga. In vitro stability was evaluated in human serum at 37/sup 0/C and showed a half-life of about 120 h for the release of /sup 67/Ga from the labeled Ab during the initial phase of incubation. This in vitro halflife is similar to that measured for /sup 111/In-DTPA labeled Abs. Because of the high stability of the /sup 67/Ga-P-EDDHA chelate, the in vivo formation of radioactive lebeled transferrin by transchelation, as described for /sup 111/In-DTPA labeled Abs, should, however, be reduced by this labeling technique.

  15. Combining EPR spectroscopy and X-ray crystallography to elucidate the structure and dynamics of conformationally constrained spin labels in T4 lysozyme single crystals.

    Science.gov (United States)

    Consentius, Philipp; Gohlke, Ulrich; Loll, Bernhard; Alings, Claudia; Heinemann, Udo; Wahl, Markus C; Risse, Thomas

    2017-08-09

    Electron paramagnetic resonance (EPR) spectroscopy in combination with site-directed spin labeling is used to investigate the structure and dynamics of conformationally constrained spin labels in T4 lysozyme single crystals. Within a single crystal, the oriented ensemble of spin bearing moieties results in a strong angle dependence of the EPR spectra. A quantitative description of the EPR spectra requires the determination of the unit cell orientation with respect to the sample tube and the orientation of the spin bearing moieties within the crystal lattice. Angle dependent EPR spectra were analyzed by line shape simulations using the stochastic Liouville equation approach developed by Freed and co-workers and an effective Hamiltonian approach. The gain in spectral information obtained from the EPR spectra of single crystalline samples taken at different frequencies, namely the X-band and Q-band, allows us to discriminate between motional models describing the spectra of isotropic solutions similarly well. In addition, it is shown that the angle dependent single crystal spectra allow us to identify two spin label rotamers with very similar side chain dynamics. These results demonstrate the utility of single crystal EPR spectroscopy in combination with spectral line shape simulation techniques to extract valuable dynamic information not readily available from the analysis of isotropic systems. In addition, it will be shown that the loss of electron density in high resolution diffraction experiments at room temperature does not allow us to conclude that there is significant structural disorder in the system.

  16. Comparison of selective arterial spin labeling using 1D and 2D tagging RF pulses

    Energy Technology Data Exchange (ETDEWEB)

    Konstandin, Simon; Heiler, Patrick M.; Schad, Lothar R. [Heidelberg Univ., Mannheim (Germany). Computer Assisted Clinical Medicine; Scharf, Johann [Heidelberg Univ., Mannheim (Germany). Dept. of Neuroradiology

    2011-07-01

    Generic arterial spin labeling (ASL) techniques label all brain feeding arteries. In this work, we used two different selective ASL (SASL) methods to show the perfusion of one single artery. A slice selective inversion of an area including the desired vessel was compared to a multidimensional RF pulse with Gaussian profile to label only the artery of interest. Perfusion images with a resolution of 2 x 2 x 5 mm{sup 3} are shown that were acquired after tagging only the internal carotid artery of healthy volunteers. In addition, both techniques were applied to a patient with an extra-intracranial bypass to illustrate its perfusion territory. These perfusion images are consistent with a standard angiography. SASL imaging with a resolution of 2 x 2 x 5 mm{sup 3} is possible in a total scan time of 5 min. The presented MR techniques may in part replace the assessment of revascularization success by conventional angiography. (orig.)

  17. Comparison of selective arterial spin labeling using 1D and 2D tagging RF pulses

    International Nuclear Information System (INIS)

    Konstandin, Simon; Heiler, Patrick M.; Schad, Lothar R.; Scharf, Johann

    2011-01-01

    Generic arterial spin labeling (ASL) techniques label all brain feeding arteries. In this work, we used two different selective ASL (SASL) methods to show the perfusion of one single artery. A slice selective inversion of an area including the desired vessel was compared to a multidimensional RF pulse with Gaussian profile to label only the artery of interest. Perfusion images with a resolution of 2 x 2 x 5 mm 3 are shown that were acquired after tagging only the internal carotid artery of healthy volunteers. In addition, both techniques were applied to a patient with an extra-intracranial bypass to illustrate its perfusion territory. These perfusion images are consistent with a standard angiography. SASL imaging with a resolution of 2 x 2 x 5 mm 3 is possible in a total scan time of 5 min. The presented MR techniques may in part replace the assessment of revascularization success by conventional angiography. (orig.)

  18. Aminocarminic acid in E120-labelled food additives and beverages.

    Science.gov (United States)

    Sabatino, Leonardo; Scordino, Monica; Gargano, Maria; Lazzaro, Francesco; Borzì, Marco A; Traulo, Pasqualino; Gagliano, Giacomo

    2012-01-01

    An analytical method was developed for investigating aminocarminic acid occurrence in E120-labelled red-coloured-beverages and in E120 additives, with the aim of controlling the purity of the carmine additive in countries where the use of aminocarminic acid is forbidden. The carminic acid and the aminocarminic acid were separated by high-performance liquid chromatography-photodiode array-tandem mass spectrography (HPLC-PDA-MS/MS). The method was statistically validated. The regression lines, ranging from 10 to 100 mg/L, showed r(2 )> 0.9996. Recoveries from 97% to 101% were obtained for the fortification level of 50 mg/L; the relative standard deviations did not exceed 3%. The LODs were below 2 mg/L, whereas the LOQs did not exceed 4 mg/L. The method was successfully applied to 27 samples of commercial E120-labelled red-coloured beverages and E120 additives, collected in Italy during quality control investigations conducted by the Ministry. The results demonstrated that more than 50% of the samples contained aminocarminic acid, evidencing the alarming illicit use of this semi-synthetic carmine acid derivative.

  19. The synthesis of taurine-conjugated bile acids and bile acid sulfates labeled with 14C or 3H in the taurine moiety

    International Nuclear Information System (INIS)

    Jie Zhang; Griffiths, W.J.; Sjoevall, Jan

    1997-01-01

    Studies of bile acid transport systems require radio-labeled taurine-conjugated bile acids with high specific activity. An established procedure was optimized to provide mild, fast, and effective conjugation of radio-labeled taurine with different types of bile acids, including those with labile 7α-hydroxy-3-oxo-Δ 4 or 3β, 7α-dihydroxy-Δ 5 structures. Taurine labeled with 14 C or 3 H was reacted with excess bile acid anhydride formed from the tributylamine salt and ethylchloroformate (2/1 M/M) in aqueous dioxane for 15 min at room temperature. The yields were higher than 95% and less than 2% side products were formed. Bile acid sulfates were conjugated with 14 C- or 3 H-labeled taurine by using N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline as the coupling reagent. The products were effectively purified by chromatography of the sodium salts on Sephadex LH-20. The yields of taurine-conjugated bile acid sulfates were 65-70%. (author)

  20. Novelties in radiology: arterial spin labeling, the gadolinium-free MR perfusion

    International Nuclear Information System (INIS)

    Goncalves, Fabricio Guimaraes; Maldjian, Joseph A.

    2011-01-01

    Arterial spin labeling (ASL) is a recently developed magnetic resonance (MR) technique that assesses cerebral blood flow. This method has been mainly used for investigative purposes with very few centers in the world performing it on a routine clinical basis. ASL has already been validated and proven to be useful in the assessment of a growing number of diseases and conditions. As with any recently established technique, ASL has some limitations that need to be overcome to become more widely used and to be part of the daily routine of the neuroimaging specialist. Currently, four major current ASL techniques are available: pulsed ASL (PASL), continuous ASL (CASL), pseudo-continuous ASL (PCASL) and velocity-selective ASL (VSASL). This article describe these techniques

  1. Arterial spin labeling blood flow magnetic resonance imaging for evaluation of renal injury.

    Science.gov (United States)

    Liu, Yupin P; Song, Rui; Liang, Chang hong; Chen, Xin; Liu, Bo

    2012-08-15

    A multitude of evidence suggests that iodinated contrast material causes nephrotoxicity; however, there have been no previous studies that use arterial spin labeling (ASL) blood flow functional magnetic resonance imaging (fMRI) to investigate the alterations in effective renal plasma flow between normointensive and hypertensive rats following injection of contrast media. We hypothesized that FAIR-SSFSE arterial spin labeling MRI may enable noninvasive and quantitative assessment of regional renal blood flow abnormalities and correlate with disease severity as assessed by histological methods. Renal blood flow (RBF) values of the cortex and medulla of rat kidneys were obtained from ASL images postprocessed at ADW4.3 workstation 0.3, 24, 48, and 72 h before and after injection of iodinated contrast media (6 ml/kg). The H&E method for morphometric measurements was used to confirm the MRI findings. The RBF values of the outer medulla were lower than those of the cortex and the inner medulla as reported previously. Iodinated contrast media treatment resulted in decreases in RBF in the outer medulla and cortex in spontaneously hypertensive rats (SHR), but only in the outer medulla in normotensive rats. The iodinated contrast agent significantly decreased the RBF value in the outer medulla and the cortex in SHR compared with normotensive rats after injection of the iodinated contrast media. Histological observations of kidney morphology were also consistent with ASL perfusion changes. These results demonstrate that the RBF value can reflect changes of renal perfusion in the cortex and medulla. ASL-MRI is a feasible and accurate method for evaluating nephrotoxic drugs-induced kidney damage.

  2. Asymmetric Synthesis of Carbon-11 Labelled alpha-Amino Acids for PET

    NARCIS (Netherlands)

    Popkov, Alexander; Elsinga, Philip H.

    2013-01-01

    For PET applications in oncological and neurological diagnostics, amino acids have been studied both clinically and pre-clinically during the last 35 years. Nowadays two applications of labelled amino acids for visualisation of tumours attract the main attention: [C-11] or [F-18]amino acids as

  3. Metabolic labeling of sialic acids in tissue culture cell lines: methods to identify substituted and modified radioactive neuraminic acids

    International Nuclear Information System (INIS)

    Diaz, S.; Varki, A.

    1985-01-01

    The parent sialic acid N-acetylneuraminic acid can be modified or substituted in various ways, giving rise to a family of more than 25 compounds. The definitive identification of these compounds has previously required isolation of nanomole amounts for mass spectrometry or NMR. We have explored the possibility of using the known metabolic precursors of the sialic acids, particularly N-acetyl-[6-3H]mannosamine, to label and identify various forms of sialic acids in tissue culture cells. Firstly, we defined several variables that affect the labeling of sialic acids with N-acetyl-[6-3H]mannosamine. Secondly, we have devised a simple screening method to identify cell lines that synthesize substituted or modified sialic acids. We next demonstrate that it is possible to definitively identify the natures of the various labeled sialic acids without the use of mass spectrometry, even though they are present only in tracer amounts. The methods used include paper chromatography, analytical de-O-acetylation, periodate release of the 9-3H as [3H]formaldehyde (which is subsequently converted to a specific 3H-labeled chromophore), acylneuraminate pyruvate lyase treatment with identification of [3H]acylmannosamines, gas-liquid chromatography with radioactive detection, and two new high-pressure liquid chromatography methods utilizing the amine-adsorption:ion suppression and ion-pair principles. The use of an internal N-acetyl-[4-14C]neuraminic acid standard in each of these methods assures precision and accuracy. The combined use of these methods now allows the identification of radioactive tracer amounts of the various types of sialic acids in well-defined populations of tissue culture cells; it may also allow the identification of hitherto unknown forms of sialic acids

  4. Self-decomposition components generated from [sup 35]S-labeled amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Takahisa; Saito, Kazumi; Kurihara, Norio (Kyoto Univ. (Japan). Radioisotope Research Center)

    1994-06-01

    We examined the fragment molecules in the gaseous components generated from [sup 35]S-amino acids with high specific radioactivity. The self-decomposition mode of a molecule labeled with a [beta]-emitter was similar to the fragmentation mode of organic compounds impacted by accelerated electrons as in organic mass spectrometry. Degradation products of unlabeled amino acids irradiated by [sup 60]Co [gamma]-ray indicated that the degradation mode induced by external [gamma]-rays irradiation was different from the self-decomposition mode of labeled compounds. (Author).

  5. Biological study of some labeled C16 fatty acids

    Energy Technology Data Exchange (ETDEWEB)

    Riche, F.; Mathieu, J.P.; Busquet, G.; Vidal, M.; Comet, M.; Pernin, C. (C.H.R.U. de Grenoble, 38 - La Tronche (France)); Godart, J.; Benabed, A. (Institut des Sciences Nucleaires, 38 - Grenoble (France)); Bardy, A. (C.E.A.-ORIS, 91 - Gif-sur-Yvette (France))

    1983-01-01

    The evolution of myocardial, blood, liver and kidney activity is studied in mice after I.V. injection of some labelled C16 fatty acids. With ..omega.. iodo fatty acids, the presence or absence of a double bond and the character Z or E have no influence on the tissue activity. The presence of a triple bond decreases the fixation, modifies the intramyocardial metabolism of the fatty acid and accelerates the rate of decrease of myocardial activity. ..omega.. bromo fatty acid have the same maximal fixation as ..omega.. iodo fatty acid but a more rapid decrease of myocardial activity. ..cap alpha.. iodo fatty acid has a very low myocardial fixation.

  6. Biological study of some labeled C16 fatty acids

    International Nuclear Information System (INIS)

    Riche, F.; Mathieu, J.P.; Busquet, G.; Vidal, M.; Comet, M.; Pernin, C.; Godart, J.; Benabed, A.; Bardy, A.

    1983-01-01

    The evolution of myocardial, blood, liver and kidney activity is studied in mice after I.V. injection of some labelled C16 fatty acids. With ω iodo fatty acids, the presence or absence of a double bond and the character Z or E have no influence on the tissue activity. The presence of a triple bond decreases the fixation, modifies the intramyocardial metabolism of the fatty acid and accelerates the rate of decrease of myocardial activity. ω bromo fatty acid have the same maximal fixation as ω iodo fatty acid but a more rapid decrease of myocardial activity. α iodo fatty acid has a very low myocardial fixation [fr

  7. Labelling of ethylenediaminetetramethylene phosphonic acid (EDTMP) with 175Yb

    International Nuclear Information System (INIS)

    Azmairit Aziz

    2009-01-01

    Ytterbium-175 ( 175 Yb) is one of radioisotopes that can be used for therapy due to its β-particle emission (T 1/2 = 4.2 d, E β(max) = 480 keV). Beside that, this radioisotope also emits γ-rays of 113 keV (1.9%), 282 keV (3.1%) and 396 keV (6.5%) which are suitable energy for imaging as long as therapeutic applications. EDTMP could be labeled with radionuclide of 175 Yb as an alternative radiopharmaceutical for bone pain palliation due to bone metastases. Labeling of ethylenediaminetetramethylenephosphonic acid with 175 Yb has been studied. Various influential parameters in labeling conditions i.e. the amount of EDTMP ligand, the pH of labeling, incubation time and the amount of 175 Yb solution were studied in order to obtain high labeling efficiency of 175 Yb-EDTMP. The labeling efficiency was obtained by radiochemical purity that was determined by paper chromatography and paper electrophoresis techniques. The optimum labeling condition was obtained at pH 7, 4 mg of EDTMP ligand, 100 µL (105 µg; 0.6 µmol) of 175 Yb solution and 30 minutes incubation time at room temperature. The complex formed was gave maximum labeling efficiency of 98.81 ± 0.15%. Owing to the results, EDTMP ligand can be labeled with 175 Yb radionuclide with labeling efficiency more than 95%. (author)

  8. Quantitative amino acid profiling and stable isotopically labeled amino acid tracer enrichment used for in vivo human systemic and tissue kinetics measurements

    DEFF Research Database (Denmark)

    Bornø, Andreas; van Hall, Gerrit

    2014-01-01

    An important area within clinical functional metabolomics is in vivo amino acid metabolism and protein turnover measurements for which accurate amino acid concentrations and stable isotopically labeled amino acid enrichments are mandatory not the least when tissue metabolomics is determined....... The present study describes a new sensitive liquid chromatography tandem mass-spectrometry method quantifying 20 amino acids and their tracer(s) ([ring-(13)C6]/D5Phenylalanine) in human plasma and skeletal muscle specimens. Before analysis amino acids were extracted and purified via deprotonization....../ion exchange, derivatized using a phenylisothiocyanate reagent and each amino acid was quantitated with its own stable isotopically labeled internal standard (uniformly labeled-(13)C/(15)N). The method was validated according to general recommendations for chromatographic analytical methods. The calibration...

  9. Experimental and clinical experience with iodine 123-labeled iodophenylpentadecanoic acid in cardiology.

    Science.gov (United States)

    Reske, S N

    1994-01-01

    Iodine 123-labeled iodophenylpentadecanoic acid (IPPA) has been synthesized for investigating myocardial free fatty acid (FFA) metabolism. The diagnostic application of labeled FFA in heart disease may be important, because FFA is the preferred substrate of cardiac energy metabolism at rest in the fasting state. In addition, regional myocardial FFA uptake and regional myocardial blood flow are tightly coupled in normal myocardium with beta-oxidation, which is extremely sensitive to oxygen deprivation. This article outlines basic physiologic pathways of cardiac IPPA metabolism in normal, acutely ischemic, and reperfused viable myocardium and summarizes the results of experimental studies in animals, validating the application of IPPA as an 123I-labeled fatty acid analog. In addition, the most important clinical studies indicating the clinical use of IPPA for diagnosis of coronary heart disease and myocardial viability are presented.

  10. Carbon-11 and Fluorine-18 Labeled Amino Acid Tracers for Positron Emission Tomography Imaging of Tumors

    Science.gov (United States)

    Sun, Aixia; Liu, Xiang; Tang, Ganghua

    2017-12-01

    Tumor cells have an increased nutritional demand for amino acids(AAs) to satisfy their rapid proliferation. Positron-emitting nuclide labeled AAs are interesting probes and are of great importance for imaging tumors using positron emission tomography (PET). Carbon-11 and fluorine-18 labeled AAs include the [1-11C] amino acids, labeling alpha-C- amino acids, the branched-chain of amino acids and N-substituted carbon-11 labeled amino acids. These tracers target protein synthesis or amino acid(AA) transport, and their uptake mechanism mainly involves AA transport. AA PET tracers have been widely used in clinical settings to image brain tumors, neuroendocrine tumors, prostate cancer, breast cancer, non–small cell lung cancer (NSCLC) and hepatocellular carcinoma. This review focuses on the fundamental concepts and the uptake mechanism of AAs, AA PET tracers and their clinical applications.

  11. Label Distribution in Tissues of Wheat Seedlings Cultivated with Tritium-Labeled Leonardite Humic Acid

    Science.gov (United States)

    Kulikova, Natalia A.; Abroskin, Dmitry P.; Badun, Gennady A.; Chernysheva, Maria G.; Korobkov, Viktor I.; Beer, Anton S.; Tsvetkova, Eugenia A.; Senik, Svetlana V.; Klein, Olga I.; Perminova, Irina V.

    2016-06-01

    Humic substances (HS) play important roles in the biotic-abiotic interactions of the root plant and soil contributing to plant adaptation to external environments. However, their mode of action on plants remains largely unknown. In this study the HS distribution in tissues of wheat seedlings was examined using tritium-labeled humic acid (HA) derived from leonardite (a variety of lignites) and microautoradiography (MAR). Preferential accumulation of labeled products from tritiated HA was found in the roots as compared to the shoots, and endodermis was shown to be the major control point for radial transport of label into vascular system of plant. Tritium was also found in the stele and xylem tissues indicating that labeled products from tritiated HA could be transported to shoot tissues via the transpiration stream. Treatment with HA lead to an increase in the content of polar lipids of photosynthetic membranes. The observed accumulation of labeled HA products in root endodermis and positive impact on lipid synthesis are consistent with prior reported observations on physiological effects of HS on plants such as enhanced growth and development of lateral roots and improvement/repairs of the photosynthetic status of plants under stress conditions.

  12. Label Distribution in Tissues of Wheat Seedlings Cultivated with Tritium-Labeled Leonardite Humic Acid

    Science.gov (United States)

    Kulikova, Natalia A.; Abroskin, Dmitry P.; Badun, Gennady A.; Chernysheva, Maria G.; Korobkov, Viktor I.; Beer, Anton S.; Tsvetkova, Eugenia A.; Senik, Svetlana V.; Klein, Olga I.; Perminova, Irina V.

    2016-01-01

    Humic substances (HS) play important roles in the biotic-abiotic interactions of the root plant and soil contributing to plant adaptation to external environments. However, their mode of action on plants remains largely unknown. In this study the HS distribution in tissues of wheat seedlings was examined using tritium-labeled humic acid (HA) derived from leonardite (a variety of lignites) and microautoradiography (MAR). Preferential accumulation of labeled products from tritiated HA was found in the roots as compared to the shoots, and endodermis was shown to be the major control point for radial transport of label into vascular system of plant. Tritium was also found in the stele and xylem tissues indicating that labeled products from tritiated HA could be transported to shoot tissues via the transpiration stream. Treatment with HA lead to an increase in the content of polar lipids of photosynthetic membranes. The observed accumulation of labeled HA products in root endodermis and positive impact on lipid synthesis are consistent with prior reported observations on physiological effects of HS on plants such as enhanced growth and development of lateral roots and improvement/repairs of the photosynthetic status of plants under stress conditions. PMID:27350412

  13. Vessel encoded arterial spin labeling with cerebral perfusion: preliminary study

    International Nuclear Information System (INIS)

    Wu Bing; Xiao Jiangxi; Xie Cheng; Wang Xiaoying; Jiang Xuexiang; Wong, E.C.; Wang Jing; Guo Jia; Zhang Beiru; Zhang Jue; Fang Jing

    2008-01-01

    Objective: To evaluate a noninvasive vessel encoded imaging for selective mapping of the flow territories of the left and fight internal carotid arteries and vertebral-basilar arteries. Methods: Seven volunteers [(33.5 ± 4.1) years; 3 men, 4 women] and 6 patients [(55.2 ± 3.2) years; 2 men, 4 women] were given written informed consent approved by the institutional review board before participating in the study. A pseudo-continuous tagging pulse train is modified to encode all vessels of interest. The selectivity of this method was demonstrated. Regional perfusion imaging was developed on the same arterial spin labeling sequence. Perfusion-weighted images of the selectively labeled cerebral arteries were obtained by subtraction of the labeled from control images. The CBF values of hemisphere, white matter, and gray matter of volunteers were calculated. The vessel territories on patients were compared with DSA. The low perfusion areas were compared with high signal areas on T 2 -FLAIR. Results: High SNR maps of left carotid, right carotid, and basilar territories were generated in 8 minutes of scan time. Cerebral blood flow values measured with regional perfusion imaging in the complete hemisphere (32.6 ± 4.3) ml·min -1 · 100 g -1 , white matter (10.8 ± 0.9) ml·min -1 ·100 g -1 , and gray matter (55.6±2.9) ml·min -1 · 100 g -1 were in agreement with data in the literature. Vessel encoded imaging in patients had a good agreement with DSA. The low perfusion areas were larger than high signal areas on T 2 -FLAIR. Conclusion: We present a new method capable of evaluating both quantitatively and qualitatively the individual brain- feeding arteries in vivo. (authors)

  14. Evaluation of sup(99m)Tc labeled amino acids as radiopharmaceuticals, 4. S-substituted cysteines and N-substituted iminodiacetic acids

    Energy Technology Data Exchange (ETDEWEB)

    Karube, Yoshiharu; Maeda, Tatsuo; Ohya, Masato; Sugata, Setsuro; Kono, Akira (Kyushu Cancer Center Research Inst., Fukuoka (Japan)); Matsushima, Yoshikazu

    1982-06-01

    Sixteen sup(99m)Tc labeled ligands were evaluated as scintigraphic agents. The ligands studied were cysteine, glutathione, their S-substituted derivatives, lysine-N sup(epsilon), N sup(epsilon)-diacetic acid, glycylglycine-N,N-diacetic acid, glycylglycylglycine-N,N-diacetic acid, taurine-N,N-diacetic acid, hydrazine-N,N-diacetic acid, ethylenediamine-N,N-diacetic acid, and propylne-1,3-diamine-N/sup 1/-,N/sup 1/-diacetic acid. The ligands were labeled with sup(99m)Tc by the SnCl/sub 2/ method with more than 95% yield. The in vivo behavior of the sup(99m)Tc labeled ligands were studied in golden hamsters and dogs. The organ distribution in golden hamsters indicated clearance both by hepatobiliary and renal systems. The pancreas/blood ratios were much lower in the sup(99m)Tc ligands than in /sup 75/Se-selenomethionine. Scintigraphic studies in dogs showed that the liver and kidneys were well visualized but the accumulation by the pancreas was not sufficient for clear visualization.

  15. Quantitation of some amino-terminal residues in proteins using 3H-labelled dansyl chloride and 14C labelled amino acids

    International Nuclear Information System (INIS)

    Flengsrud, R.

    1979-01-01

    A method for quantitation of amino-terminal residues in proteins is presented. The method is a modification of a double isotope-labelling technique, using 3 H-labelled dansyl chloride and 14 C-labelled amino acids as internal standards. The method is demonstrated on human fibrinogen, horse myoglobin and on mouse myoloma IgA. A linear relationship between the ratio 3 H/ 14 C in the separated amino-terminal amino acid of the protein and the amount of protein added in the labelling mixture was obtained with standard deviations of +- 7.4%, +-3.4% and +-10.3%, respectively. An application of the method is demonstrated by measuring the increase in amino-terminal glycine in fibrinogen following the proteolytic action of thrombin. The method seems to be useful when 0.1 nmol or more of protein is used. (author)

  16. Characterisation and vapour sensing properties of spin coated thin films of anthracene labelled PMMA polymer

    Energy Technology Data Exchange (ETDEWEB)

    Capan, I., E-mail: inci.capan@gmail.com [Balikesir University, Faculty of Art and Sciences, Department of Physics, Cagis Campus, 10145 Balikesir (Turkey); Tarimci, C., E-mail: Celik.Tarimci@eng.ankara.edu.tr [Ankara University, Faculty of Engineering, Department of Engineering Physics, 06100, Ankara (Turkey); Erdogan, M., E-mail: merdogan@balikesir.edu.tr [Balikesir University, Faculty of Art and Sciences, Department of Physics, Cagis Campus, 10145 Balikesir (Turkey); Hassan, A.K., E-mail: A.Hassan@shu.ac.uk [Materials and Engineering Research Institute, Sheffield Hallam University, Sheaf Building, Pond Street, Sheffield S1 1WB (United Kingdom)

    2009-05-05

    In the present article thin films of poly (methyl methacrylate) (PMMA) polymer labelled with anthracene (Ant-PMMA) prepared by spin coating are characterised by UV-visible spectroscopy, surface plasmon resonance (SPR), spectroscopic ellipsometry (SE) and Atomic Force Microscopy (AFM) and their organic vapour sensing properties are investigated. Ant-PMMA films' thickness are determined by performing theoretical fitting to experimental data measured using SPR and SE. Results obtained show that the spin-cast films are of good uniformity with an average thickness of 6-8 nm. Organic vapour sensing properties are studied using SPR technique during exposures to different volatile organic compounds (VOCs). Ant-PMMA films' response to the selected VOCs has been examined in terms of solubility parameters and molar volumes of the solvents, and the films were found to be largely sensitive to benzene vapour compared to other studied analytes.

  17. Characterisation and vapour sensing properties of spin coated thin films of anthracene labelled PMMA polymer

    International Nuclear Information System (INIS)

    Capan, I.; Tarimci, C.; Erdogan, M.; Hassan, A.K.

    2009-01-01

    In the present article thin films of poly (methyl methacrylate) (PMMA) polymer labelled with anthracene (Ant-PMMA) prepared by spin coating are characterised by UV-visible spectroscopy, surface plasmon resonance (SPR), spectroscopic ellipsometry (SE) and Atomic Force Microscopy (AFM) and their organic vapour sensing properties are investigated. Ant-PMMA films' thickness are determined by performing theoretical fitting to experimental data measured using SPR and SE. Results obtained show that the spin-cast films are of good uniformity with an average thickness of 6-8 nm. Organic vapour sensing properties are studied using SPR technique during exposures to different volatile organic compounds (VOCs). Ant-PMMA films' response to the selected VOCs has been examined in terms of solubility parameters and molar volumes of the solvents, and the films were found to be largely sensitive to benzene vapour compared to other studied analytes.

  18. Tetrazine-Containing Amino Acid for Peptide Modification and Live Cell Labeling.

    Directory of Open Access Journals (Sweden)

    Zhongqiu Ni

    Full Text Available A novel amino acid derivative 3-(4-(1, 2, 4, 5-tetrazine-3-yl phenyl-2-aminopropanoic acid was synthesized in this study. The compound possessed better water-solubility and was synthesized more easily compared with the well-known and commercially available 3-(p-benzylamino-1, 2, 4, 5-tetrazine. Tetrazine-containing amino acid showed excellent stability in biological media and might be used for cancer cell labeling. Moreover, the compound remained relatively stable in 50% TFA/DCM with little decomposition after prolonged exposure at room temperature. The compound could be utilized as phenylalanine or tyrosine analogue in peptide modification, and the tetrazine-containing peptide demonstrated more significant biological activity than that of the parent peptide. The combination of tetrazine group and amino acid offered broad development prospects of the bioorthogonal labeling and peptide synthesis.

  19. Liquid–liquid extraction combined with differential isotope dimethylaminophenacyl labeling for improved metabolomic profiling of organic acids

    International Nuclear Information System (INIS)

    Peng, Jun; Li, Liang

    2013-01-01

    Graphical abstract: -- Highlights: •An improved method for profiling the carboxylic acid sub-metabolome is reported. •Liquid–liquid extraction was used for separating the organic acids from the amines. • 12 C/ 13 C-p-dimethylaminophenacyl (DmPA) labeling of the organic acids was carried out on the extract. •Detection interference by amines and labeling efficiency reduction by water were reduced. •About 2500 12 C/ 13 C-peak pairs or putative metabolites could be detected from 20 μL of human urine. -- Abstract: A large fraction of the known human metabolome belong to organic acids. However, comprehensive profiling of the organic acid sub-metabolome is a major analytical challenge. In this work, we report an improved method for detecting organic acid metabolites. This method is based on the use of liquid–liquid extraction (LLE) to selectively extract the organic acids, followed by using differential isotope p-dimethylaminophenacyl (DmPA) labeling of the acid metabolites. The 12 C-/ 13 C-labeled samples are analyzed by liquid chromatography Fourier-transform ion cyclotron resonance mass spectrometry (LC–FTICR–MS). It is shown that this LLE DmPA labeling method offers superior performance over the method of direct DmPA labeling of biofluids such as human urine. LLE of organic acids reduces the interference of amine-containing metabolites that may also react with DmPA. It can also remove water in a biofluid that can reduce the labeling efficiency. Using human urine as an example, it is demonstrated that about 2500 peak pairs or putative metabolites could be detected in a 30-min gradient LC–MS run, which is about 3 times more than that detected in a sample prepared using direct DmPA labeling. About 95% of the 1000 or so matched metabolites to the Human Metabolome Database (HMDB) are organic acids. It is further shown that this method can be used to handle as small as 10 μL of urine. We believe that this method opens the possibility of generating a

  20. Liquid–liquid extraction combined with differential isotope dimethylaminophenacyl labeling for improved metabolomic profiling of organic acids

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Jun; Li, Liang, E-mail: Liang.Li@ualberta.ca

    2013-11-25

    Graphical abstract: -- Highlights: •An improved method for profiling the carboxylic acid sub-metabolome is reported. •Liquid–liquid extraction was used for separating the organic acids from the amines. •{sup 12}C/{sup 13}C-p-dimethylaminophenacyl (DmPA) labeling of the organic acids was carried out on the extract. •Detection interference by amines and labeling efficiency reduction by water were reduced. •About 2500 {sup 12}C/{sup 13}C-peak pairs or putative metabolites could be detected from 20 μL of human urine. -- Abstract: A large fraction of the known human metabolome belong to organic acids. However, comprehensive profiling of the organic acid sub-metabolome is a major analytical challenge. In this work, we report an improved method for detecting organic acid metabolites. This method is based on the use of liquid–liquid extraction (LLE) to selectively extract the organic acids, followed by using differential isotope p-dimethylaminophenacyl (DmPA) labeling of the acid metabolites. The {sup 12}C-/{sup 13}C-labeled samples are analyzed by liquid chromatography Fourier-transform ion cyclotron resonance mass spectrometry (LC–FTICR–MS). It is shown that this LLE DmPA labeling method offers superior performance over the method of direct DmPA labeling of biofluids such as human urine. LLE of organic acids reduces the interference of amine-containing metabolites that may also react with DmPA. It can also remove water in a biofluid that can reduce the labeling efficiency. Using human urine as an example, it is demonstrated that about 2500 peak pairs or putative metabolites could be detected in a 30-min gradient LC–MS run, which is about 3 times more than that detected in a sample prepared using direct DmPA labeling. About 95% of the 1000 or so matched metabolites to the Human Metabolome Database (HMDB) are organic acids. It is further shown that this method can be used to handle as small as 10 μL of urine. We believe that this method opens the

  1. A cost-effective approach to produce 15N-labelled amino acids employing Chlamydomonas reinhardtii CC503.

    Science.gov (United States)

    Nicolás Carcelén, Jesús; Marchante-Gayón, Juan Manuel; González, Pablo Rodríguez; Valledor, Luis; Cañal, María Jesús; Alonso, José Ignacio García

    2017-08-18

    The use of enriched stable isotopes is of outstanding importance in chemical metrology as it allows the application of isotope dilution mass spectrometry (IDMS). Primary methods based on IDMS ensure the quality of the analytical measurements and traceability of the results to the international system of units. However, the synthesis of isotopically labelled molecules from enriched stable isotopes is an expensive and a difficult task. Either chemical and biochemical methods to produce labelled molecules have been proposed, but so far, few cost-effective methods have been described. The aim of this study was to use the microalgae Chlamydomonas reinhardtii to produce, at laboratory scale, 15 N-labelled amino acids with a high isotopic enrichment. To do that, a culture media containing 15 NH 4 Cl was used. No kinetic isotope effect (KIE) was observed. The labelled proteins biosynthesized by the microorganism were extracted from the biomass and the 15 N-labelled amino acids were obtained after a protein hydrolysis with HCl. The use of the wall deficient strain CC503 cw92 mt+ is fit for purpose, as it only assimilates ammonia as nitrogen source, avoiding isotope contamination with nitrogen from the atmosphere or the reagents used in the culture medium, and enhancing the protein extraction efficiency compared to cell-walled wild type Chlamydomonas. The isotopic enrichment of the labelled amino acids was calculated from their isotopic composition measured by gas chromatography mass spectrometry (GC-MS). The average isotopic enrichment for the 16 amino acids characterized was 99.56 ± 0.05% and the concentration of the amino acids in the hydrolysate ranged from 18 to 90 µg/mL. Previously reported biochemical methods to produce isotopically labelled proteins have been applied in the fields of proteomics and fluxomics. For these approaches, low amounts of products are required and the isotopic enrichment of the molecules has never been properly determined. So far, only 13

  2. Application of Arterial Spin Labelling in Detecting Retinal Ischemia

    Directory of Open Access Journals (Sweden)

    Ehsan Vaghefi

    2017-12-01

    Full Text Available Purpose: Here, we have tried to quantify the chorioretinal blood perfusion in patients who are clinically identified to be suffering from retinal ischemia using arterial spin labelling (ASL MRI. Method: Four participants, diagnosed with retinal ischemia based on their structural OCT and angiography test, were then scanned using anatomical MRI as well as ASL. We optimized MR parameters to maximize resolution and target fixation, blinking, and breathing ques to minimize motion artifacts. Results: Participants had a maximum of ∼50 mL/100 mL/min of blood perfusion, which is below the normal values of ∼200 mL/100 mL/min. It also appeared that thinning of the choroid contributes more to the measured decreased chorioretinal perfusion, compared to slowed arterial filling time. Conclusion: Decreased chorioretinal perfusion is a multifactorial event and has been implicated in several posterior eye pathologies. Based on our current results, it seems that ischemia of the eye could be due to anatomy (tissue volume and/or functionality (arterial flow.

  3. Mass spectrometric studies of stable isotope-labelled carboxylic acid derivatives

    International Nuclear Information System (INIS)

    Andersson, B.Aa.; Dinger, F.; Dinh-Nguyen, N.

    1975-01-01

    Low resolution mass spectra of deuterium and carbon-13 labelled fatty acid pyrrolidides are discussed. The simple fragmentation pattern of pyrrolidides makes them superior to other derivatives, regarding location of isotopes. Deuteriation of ethylenic fatty acid pyrrolidides therefore seems to be an improved method to locate carbon-carbon double bonds by mass spectrometry. (author)

  4. Conformational change in full-length mouse prion: A site-directed spin-labeling study

    International Nuclear Information System (INIS)

    Inanami, Osamu; Hashida, Shukichi; Iizuka, Daisuke; Horiuchi, Motohiro; Hiraoka, Wakako; Shimoyama, Yuhei; Nakamura, Hideo; Inagaki, Fuyuhiko; Kuwabara, Mikinori

    2005-01-01

    The structure of the mouse prion (moPrP) was studied using site-directed spin-labeling electron spin resonance (SDSL-ESR). Since a previous NMR study by Hornemanna et al., [Hornemanna, Korthb, Oeschb, Rieka, Widera, Wuethricha, Glockshubera, Recombinant full-length murine prion protein, mPrP (23-231): purification and spectroscopic characterization, FEBS Lett. 413 (1997) 277-281] has indicated that N96, D143, and T189 in moPrP are localized in a Cu 2+ binding region, Helix1 and Helix2, respectively, three recombinant moPrP mutations (N96C, D143C, and T189C) were expressed in an Escherichia coli system, and then refolded by dialysis under low pH and purified by reverse-phase HPLC. By using the preparation, we succeeded in preserving a target cystein residue without alteration of the α-helix structure of moPrP and were able to apply SDSL-ESR with a methane thiosulfonate spin label to the full-length prion protein. The rotational correlation times (τ) of 1.1, 3.3, and 4.8 ns were evaluated from the X-band ESR spectra at pH 7.4 and 20 deg C for N96R1, D143R1, and T189R1, respectively. τ reflects the fact that the Cu 2+ binding region is more flexible than Helix1 or Helix2. ESR spectra recorded at various temperatures revealed two phases together with a transition point at around 20 deg C in D143R1 and T189R1, but not in N96R1. With the variation of pH from 4.0 to 7.8, ESR spectra of T189R1 at 20 deg C showed a gradual increase of τ from 2.9 to 4.8 ns. On the other hand, the pH-dependent conformational changes in N96R1 and D143R1 were negligible. These results indicated that T189 located in Helix2 possessed a structure sensitive to physiological pH changes; simultaneously, N96 in the Cu 2+ binding region and D143 in Helix1 were conserved

  5. Effect of thiol reactive reagents and ionizing radiation on the permeability of erythrocyte membrane for non-electrolyte spin labels

    International Nuclear Information System (INIS)

    Gwozdzinski, K.

    1986-01-01

    The paper presents some results on the effect of PCMB and NEM on the transport of non-electrolyte spin labels: TEMPO and TEMPOL across non-irradiated and irradiated porcine erythrocyte. Irradiated erythrocytes exhibited increased inhibitory effect of thiol reactive compounds in the TEMPO and TEMPOL transport compared to non-irradiated erythrocytes. (orig.)

  6. Single-Labeled Oligonucleotides Showing Fluorescence Changes upon Hybridization with Target Nucleic Acids

    Directory of Open Access Journals (Sweden)

    Gil Tae Hwang

    2018-01-01

    Full Text Available Sequence-specific detection of nucleic acids has been intensively studied in the field of molecular diagnostics. In particular, the detection and analysis of single-nucleotide polymorphisms (SNPs is crucial for the identification of disease-causing genes and diagnosis of diseases. Sequence-specific hybridization probes, such as molecular beacons bearing the fluorophore and quencher at both ends of the stem, have been developed to enable DNA mutation detection. Interestingly, DNA mutations can be detected using fluorescently labeled oligonucleotide probes with only one fluorophore. This review summarizes recent research on single-labeled oligonucleotide probes that exhibit fluorescence changes after encountering target nucleic acids, such as guanine-quenching probes, cyanine-containing probes, probes containing a fluorophore-labeled base, and microenvironment-sensitive probes.

  7. The synthesis of taurine-conjugated bile acids and bile acid sulfates labeled with {sup 14}C or {sup 3}H in the taurine moiety

    Energy Technology Data Exchange (ETDEWEB)

    Jie Zhang; Griffiths, W.J.; Sjoevall, Jan [Karolinska Inst., Medical Biochemistry and Biophysics Dept., Stockholm (Sweden)

    1997-02-01

    Studies of bile acid transport systems require radio-labeled taurine-conjugated bile acids with high specific activity. An established procedure was optimized to provide mild, fast, and effective conjugation of radio-labeled taurine with different types of bile acids, including those with labile 7{alpha}-hydroxy-3-oxo-{Delta}{sup 4} or 3{beta}, 7{alpha}-dihydroxy-{Delta}{sup 5} structures. Taurine labeled with {sup 14}C or {sup 3}H was reacted with excess bile acid anhydride formed from the tributylamine salt and ethylchloroformate (2/1 M/M) in aqueous dioxane for 15 min at room temperature. The yields were higher than 95% and less than 2% side products were formed. Bile acid sulfates were conjugated with {sup 14}C- or {sup 3}H-labeled taurine by using N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline as the coupling reagent. The products were effectively purified by chromatography of the sodium salts on Sephadex LH-20. The yields of taurine-conjugated bile acid sulfates were 65-70%. (author).

  8. Synthesis of deuterium labeled perillyl alcohol and dual C-13 and deuterium labeled perillic acid, major metabolites of d-limonene

    International Nuclear Information System (INIS)

    Chen, Haitao; Chan, K.C.

    1997-01-01

    Dual C-13 and deuterium labeled perillic acid, [(1,1-dideuterio-1- 13 C-2-methyl)ethenyl]-1-cyclohexene -1-carboxylic acid (6) and deuterated perillyl alcohol, [(2,2-dideuterio-1-methyl)ethenyl]-1-deuteriohydroxymethyl-1-cyclo -hexene (9) were synthesized from commercially available (4S)-(-)-perillaidehyde (1). Compound 1 was first protected with ethylene glycol to yield the ethylene ketal followed by oxidation with OsO 4 /NalO 4 to cleave the terminal double bond to afford the key intermediate ketone, 4-acetyl-1-cyclohexene-1-carboxaldehyde ethylene ketal (3). 3 was then converted to the labeled perillyl aldehyde by Wittig reaction with prepared Ph 3 P 13 CD 3 l or Ph 3 PCD 3 l. Followed by deprotection to give the labeled perillaldehydes, [(2,2-dideuterio-2- 13 C-1-methyl)ethenyl] -1-cyclohexene-1-carboxaldehyde-1-carboxaldehyde (5) or [(2,2-dideuterio-1-methyl)ethenyl] -1-cyclohexene-1-carboxaldehyde (8). 5 was further oxidized by freshly prepared Ag 2 O to give the desired compound 6. 8 was reduced by LiAID 4 to afford the desired compound 9. The same synthetic procedure may be adopted to synthesize the radioactive isotope labeled perillic acid and perilly alcohol. (author)

  9. Quantification of renal allograft perfusion using arterial spin labeling MRI: initial results.

    Science.gov (United States)

    Lanzman, Rotem S; Wittsack, Hans-Jörg; Martirosian, Petros; Zgoura, Panagiota; Bilk, Philip; Kröpil, Patric; Schick, Fritz; Voiculescu, Adina; Blondin, Dirk

    2010-06-01

    To quantify renal allograft perfusion in recipients with stable allograft function and acute decrease in allograft function using nonenhanced flow-sensitive alternating inversion recovery (FAIR)-TrueFISP arterial spin labeling (ASL) MR imaging. Following approval of the local ethics committee, 20 renal allograft recipients were included in this study. ASL perfusion measurement and an anatomical T2-weighted single-shot fast spin-echo (HASTE) sequence were performed on a 1.5-T scanner (Magnetom Avanto, Siemens, Erlangen, Germany). T2-weighted MR urography was performed in patients with suspected ureteral obstruction. Patients were assigned to three groups: group a, 6 patients with stable allograft function over the previous 4 months; group b, 7 patients with good allograft function who underwent transplantation during the previous 3 weeks; group c, 7 allograft recipients with an acute deterioration of renal function. Mean cortical perfusion values were 304.8 +/- 34.4, 296.5 +/- 44.1, and 181.9 +/- 53.4 mg/100 ml/min for groups a, b and c, respectively. Reduction in cortical perfusion in group c was statistically significant. Our results indicate that ASL is a promising technique for nonenhanced quantification of cortical perfusion of renal allografts. Further studies are required to determine the clinical value of ASL for monitoring renal allograft recipients.

  10. Quantification of renal allograft perfusion using arterial spin labeling MRI: initial results

    International Nuclear Information System (INIS)

    Lanzman, Rotem S.; Wittsack, Hans-Joerg; Bilk, Philip; Kroepil, Patric; Blondin, Dirk; Martirosian, Petros; Schick, Fritz; Zgoura, Panagiota; Voiculescu, Adina

    2010-01-01

    To quantify renal allograft perfusion in recipients with stable allograft function and acute decrease in allograft function using nonenhanced flow-sensitive alternating inversion recovery (FAIR)-TrueFISP arterial spin labeling (ASL) MR imaging. Following approval of the local ethics committee, 20 renal allograft recipients were included in this study. ASL perfusion measurement and an anatomical T2-weighted single-shot fast spin-echo (HASTE) sequence were performed on a 1.5-T scanner (Magnetom Avanto, Siemens, Erlangen, Germany). T2-weighted MR urography was performed in patients with suspected ureteral obstruction. Patients were assigned to three groups: group a, 6 patients with stable allograft function over the previous 4 months; group b, 7 patients with good allograft function who underwent transplantation during the previous 3 weeks; group c, 7 allograft recipients with an acute deterioration of renal function. Mean cortical perfusion values were 304.8 ± 34.4, 296.5 ± 44.1, and 181.9 ± 53.4 mg/100 ml/min for groups a, b and c, respectively. Reduction in cortical perfusion in group c was statistically significant. Our results indicate that ASL is a promising technique for nonenhanced quantification of cortical perfusion of renal allografts. Further studies are required to determine the clinical value of ASL for monitoring renal allograft recipients. (orig.)

  11. A new label dosimetry system based on pentacosa-diynoic acid monomer for low dose applications

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Fattah, A.A.; Abdel-Rehim, F. [National Center for Radiation Research and Technology, Atomic Energy Authority, P.O. Box 8029, Nasr City, Cairo (Egypt); Soliman, Y.S., E-mail: yasser_shabaan@hotmail.com [National Center for Radiation Research and Technology, Atomic Energy Authority, P.O. Box 8029, Nasr City, Cairo (Egypt)

    2012-01-15

    The dosimetric characteristics of {gamma}-radiation sensitive labels based on polyvinyl butyral (PVB) and a conjugated diacetylene monomer, 10,12-pentacosa-diynoic acid (PCDA) have been investigated using reflectance colorimeter. Two types of labels (colourless and yellow) based on PCDA monomer were prepared using an Automatic Film Applicator System. Upon {gamma}-ray exposure, the colourless label turns progressively blue, while the yellow colour label turns to green then to dark blue. The colour intensity of the labels is proportional to the radiation absorbed dose. The useful dose range was 15 Gy-2 kGy depending on PCDA monomer concentration. The expanded uncertainty of dose measurement of the colourless label was 6.06 (2{sigma}). - Highlights: > Using 10,12-pentacosa-diynoic acid (PCDA) in preparation of label dosimeter. > PCDA polymerises upon {gamma}-rays exposure producing a blue coloured polymer. > Useful dose range is 15 Gy to 2 kGy depending on concentration of PCDA. > Overall uncertainty of label dosimeter was 6.06 at 2{sigma}.

  12. An inproved synthesis of 24- 13C-labeled bile acids using formyl esters and a modified lead tetraacetate procedure

    International Nuclear Information System (INIS)

    Tserng, K.Y.; Klein, P.D.

    1977-01-01

    An improved synthesis of 24- 13 C-labeled bile acids has been achieved using formyl derivatives of bile acids and a modified lead tetraacetate procedure. The formylated bile acids were degraded by lead tetraacetate and lithium chloride to formylated 23-chloronorcholanes in 72 to 83% yield. Formylated 23-chloronorcholanes were converted to nitriles in dimethylformamide, which were then hydrolyzed to obtain C-24 labeled bile acids in yield of 80 to 90% of labeled sodium cyanide used. This method results in a higher yield and a purer product with less manipulation than previously reported procedures for synthesis of labeled bile acids

  13. Elucidating the design principles of photosynthetic electron-transfer proteins by site-directed spin labeling EPR spectroscopy.

    Science.gov (United States)

    Ishara Silva, K; Jagannathan, Bharat; Golbeck, John H; Lakshmi, K V

    2016-05-01

    Site-directed spin labeling electron paramagnetic resonance (SDSL EPR) spectroscopy is a powerful tool to determine solvent accessibility, side-chain dynamics, and inter-spin distances at specific sites in biological macromolecules. This information provides important insights into the structure and dynamics of both natural and designed proteins and protein complexes. Here, we discuss the application of SDSL EPR spectroscopy in probing the charge-transfer cofactors in photosynthetic reaction centers (RC) such as photosystem I (PSI) and the bacterial reaction center (bRC). Photosynthetic RCs are large multi-subunit proteins (molecular weight≥300 kDa) that perform light-driven charge transfer reactions in photosynthesis. These reactions are carried out by cofactors that are paramagnetic in one of their oxidation states. This renders the RCs unsuitable for conventional nuclear magnetic resonance spectroscopy investigations. However, the presence of native paramagnetic centers and the ability to covalently attach site-directed spin labels in RCs makes them ideally suited for the application of SDSL EPR spectroscopy. The paramagnetic centers serve as probes of conformational changes, dynamics of subunit assembly, and the relative motion of cofactors and peptide subunits. In this review, we describe novel applications of SDSL EPR spectroscopy for elucidating the effects of local structure and dynamics on the electron-transfer cofactors of photosynthetic RCs. Because SDSL EPR Spectroscopy is uniquely suited to provide dynamic information on protein motion, it is a particularly useful method in the engineering and analysis of designed electron transfer proteins and protein networks. This article is part of a Special Issue entitled Biodesign for Bioenergetics--the design and engineering of electronic transfer cofactors, proteins and protein networks, edited by Ronald L. Koder and J.L. Ross Anderson. Copyright © 2016. Published by Elsevier B.V.

  14. Perfusion magnetic resonance imaging with continuous arterial spin labeling: methods and clinical applications in the central nervous system

    Energy Technology Data Exchange (ETDEWEB)

    Detre, John A. E-mail: detre@mail.med.upenn.edu; Alsop, David C

    1999-05-01

    Several methods are now available for measuring cerebral perfusion and related hemodynamic parameters using magnetic resonance imaging (MRI). One class of techniques utilizes electromagnetically labeled arterial blood water as a noninvasive diffusible tracer for blood flow measurements. The electromagnetically labeled tracer has a decay rate of T1, which is sufficiently long to allow perfusion of the tissue and microvasculature to be detected. Alternatively, electromagnetic arterial spin labeling (ASL) may be used to obtain qualitative perfusion contrast for detecting changes in blood flow, similar to the use of susceptibility contrast in blood oxygenation level dependent functional MRI (BOLD fMRI) to detect functional activation in the brain. The ability to obtain blood flow maps using a non-invasive and widely available modality such as MRI should greatly enhance the utility of blood flow measurement as a means of gaining further insight into the broad range of hemodynamically related physiology and pathophysiology. This article describes the biophysical considerations pertaining to the generation of quantitative blood flow maps using a particular form of ASL in which arterial blood water is continuously labeled, termed continuous arterial spin labeling (CASL). Technical advances permit multislice perfusion imaging using CASL with reduced sensitivity to motion and transit time effects. Interpretable cerebral perfusion images can now be reliably obtained in a variety of clinical settings including acute stroke, chronic cerebrovascular disease, degenerative diseases and epilepsy. Over the past several years, the technical and theoretical foundations of CASL perfusion MRI techniques have evolved from feasibility studies into practical usage. Currently existing methodologies are sufficient to make reliable and clinically relevant observations which complement structural assessment using MRI. Future technical improvements should further reduce the acquisition times

  15. A Tc-99m-labeled long chain fatty acid derivative for myocardial imaging.

    Science.gov (United States)

    Magata, Yasuhiro; Kawaguchi, Takayoshi; Ukon, Misa; Yamamura, Norio; Uehara, Tomoya; Ogawa, Kazuma; Arano, Yasushi; Temma, Takashi; Mukai, Takahiro; Tadamura, Eiji; Saji, Hideo

    2004-01-01

    C-11- and I-123-labeled long chain fatty acid derivatives have been reported as useful radiopharmaceuticals for the estimation of myocardial fatty acid metabolism. We have reported that Tc-99m-labeled N-[[[(2-mercaptoethyl)amino]carbonyl]methyl]-N-(2-mercaptoethyl)-6-aminohexanoic acid ([(99m)Tc]MAMA-HA), a medium chain fatty acid derivative, is metabolized by beta-oxidation in the liver and that the MAMA ligand is useful for attaching to the omega-position of fatty acid derivatives as a chelating group for Tc-99m. On the basis of these findings, we focused on developing a Tc-99m-labeled long chain fatty acid derivative that reflected fatty acid metabolism in the myocardium. In this study, we synthesized a dodecanoic acid derivative, MAMA-DA, and a hexadecanoic acid derivative, MAMA-HDA, and performed radiolabeling and biodistribution studies. [(99m)Tc]MAMA-DA and [(99m)Tc]MAMA-HDA were prepared using a ligand-exchange reaction. Biodistribution studies were carried out in normal mice and rats. Then, a high initial uptake of Tc-99m was observed, followed by a rapid clearance from the heart. The maximum heart/blood ratio was 3.6 at 2 min postinjection of [(99m)Tc]MAMA-HDA. These kinetics were similar to those with postinjection of p-[(125)I]iodophenylpentadecanoic acid. Metabolite analysis showed [(99m)Tc]MAMA-HDA was metabolized by beta-oxidation in the body. In conclusion, [(99m)Tc]MAMA-HDA is a promising compound as a long chain fatty acid analogue for estimating beta-oxidation of fatty acid in the heart.

  16. Morpholino spin-labeling for base-pair sequencing of a 3'-terminal RNA stem by proton homonuclear Overhauser enhancements: yeast ribosomal 5S RNA

    International Nuclear Information System (INIS)

    Lee, K.M.; Marshall, A.G.

    1987-01-01

    Base-pair sequences for 5S and 5.8S RNAs are not readily extracted from proton homonuclear nuclear Overhauser enhancement (NOE) connectivity experiments alone, due to extensive peak overlap in the downfield (11-15 ppm) proton NMR spectrum. In this paper, we introduce a new method for base-pair proton peak assignment for ribosomal RNAs, based upon the distance-dependent broadening of the resonances of base-pair protons spatially proximal to a paramagnetic group. Introduction of a nitroxide spin-label covalently attached to the 3'-terminal ribose provides an unequivocal starting point for base-pair hydrogen-bond proton NMR assignment. Subsequent NOE connectivities then establish the base-pair sequence for the terminal stem of a 5S RNA. Periodate oxidation of yeast 5S RNA, followed by reaction with 4-amino-2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO-NH2) and sodium borohydride reduction, produces yeast 5S RNA specifically labeled with a paramagnetic nitroxide group at the 3'-terminal ribose. Comparison of the 500-MHz 1H NMR spectra of native and 3'-terminal spin-labeled yeast 5S RNA serves to identify the terminal base pair (G1 . C120) and its adjacent base pair (G2 . U119) on the basis of their proximity to the 3'-terminal spin-label. From that starting point, we have then identified (G . C, A . U, or G . U) and sequenced eight of the nine base pairs in the terminal helix via primary and secondary NOE's

  17. Solid phase labelling of technetium-99m glutamic acid: Radiopharmacological studies

    International Nuclear Information System (INIS)

    Campos, E.; Kremer, C.; Leon, A.; Martinez, G.; Gaudiano, J.

    1989-01-01

    Amino acids labelled with 11 C and 13 N are used in localizing tumours, and in scintiscanning pancreas and myocardium. The behaviour of glutamic acid labelled with 99m Tc in healthy and tumour bearing animals is described. Under optimal conditions, a labelling efficiency of 26% is obtained, with a radiochemical purity of 96% and no detectable colloids. Zinc concentrations in the final preparation are well below those at which chemical toxicity becomes apparent. Previous studies suggest the structure as that of an oxotechnetium complex (TcO 2 (glu 2 )) 4- (pH 6). Biodistribution studies have been performed in normal mice. Paper electrophoresis shows that the complex is excreted unchanged via the kidneys. In animals with adenocarcinoma at various stages of differentiation, tumour to blood ratios of between 0.4 and 2.0 are observed. Blood clearance and renal excretion in human subjects are reported and uptake in human breast carcinoma is demonstrated. (author)

  18. Do "good" food products make others look "bad"? Spin-off effects of labels for sustainable food production in the consumer perception

    NARCIS (Netherlands)

    Binnekamp, M.H.A.; Ingenbleek, P.T.M.

    2008-01-01

    Abstract Purpose ¿ The objective of this study is to examine whether sustainability labels like Fair Trade have a spin-off effect to mainstream products in the consumer perception: do consumers perceive mainstream products and brands more negatively in the presence of a product with a sustainability

  19. SU-G-IeP1-15: Towards Accurate Cerebral Blood Flow Quantification with Distortion- Corrected Pseudo-Continuous Arterial Spin Labeling

    Energy Technology Data Exchange (ETDEWEB)

    Hoff, M; Rane-Levandovsky, S; Andre, J [University of Washington, Seattle, WA (United States)

    2016-06-15

    Purpose: Traditional arterial spin labeling (ASL) acquisitions with echo planar imaging (EPI) readouts suffer from image distortion due to susceptibility effects, compromising ASL’s ability to accurately quantify cerebral blood flow (CBF) and assess disease-specific patterns associated with CBF abnormalities. Phase labeling for additional coordinate encoding (PLACE) can remove image distortion; our goal is to apply PLACE to improve the quantitative accuracy of ASL CBF in humans. Methods: Four subjects were imaged on a 3T Philips Ingenia scanner using a 16-channel receive coil with a 21/21/10cm (frequency/phase/slice direction) field-of-view. An ASL sequence with a pseudo-continuous ASL (pCASL) labeling scheme was employed to acquire thirty dynamics of single-shot EPI data, with control and label datasets for all dynamics, and PLACE gradients applied on odd dynamics. Parameters included a post-labeling delay = 2s, label duration = 1.8s, flip angle = 90°, TR/TE = 5000/23.5ms, and 2.9/2.9/5.0mm (frequency/phase/slice direction) voxel size. “M0” EPI-reference images and T1-weighted spin-echo images with 0.8/1.0/3.3mm (frequency/phase/slice directions) voxel size were also acquired. Complex conjugate image products of pCASL odd and even dynamics were formed, a linear phase ramp applied, and data expanded and smoothed. Data phase was extracted to map control, label, and M0 magnitude image pixels to their undistorted locations, and images were rebinned to original size. All images were corrected for motion artifacts in FSL 5.0. pCASL images were registered to M0 images, and control and label images were subtracted to compute quantitative CBF maps. Results: pCASL image and CBF map distortions were removed by PLACE in all subjects. Corrected images conformed well to the anatomical T1-weighted reference image, and deviations in corrected CBF maps were evident. Conclusion: Eliminating pCASL distortion with PLACE can improve CBF quantification accuracy using minimal

  20. SU-G-IeP1-15: Towards Accurate Cerebral Blood Flow Quantification with Distortion- Corrected Pseudo-Continuous Arterial Spin Labeling

    International Nuclear Information System (INIS)

    Hoff, M; Rane-Levandovsky, S; Andre, J

    2016-01-01

    Purpose: Traditional arterial spin labeling (ASL) acquisitions with echo planar imaging (EPI) readouts suffer from image distortion due to susceptibility effects, compromising ASL’s ability to accurately quantify cerebral blood flow (CBF) and assess disease-specific patterns associated with CBF abnormalities. Phase labeling for additional coordinate encoding (PLACE) can remove image distortion; our goal is to apply PLACE to improve the quantitative accuracy of ASL CBF in humans. Methods: Four subjects were imaged on a 3T Philips Ingenia scanner using a 16-channel receive coil with a 21/21/10cm (frequency/phase/slice direction) field-of-view. An ASL sequence with a pseudo-continuous ASL (pCASL) labeling scheme was employed to acquire thirty dynamics of single-shot EPI data, with control and label datasets for all dynamics, and PLACE gradients applied on odd dynamics. Parameters included a post-labeling delay = 2s, label duration = 1.8s, flip angle = 90°, TR/TE = 5000/23.5ms, and 2.9/2.9/5.0mm (frequency/phase/slice direction) voxel size. “M0” EPI-reference images and T1-weighted spin-echo images with 0.8/1.0/3.3mm (frequency/phase/slice directions) voxel size were also acquired. Complex conjugate image products of pCASL odd and even dynamics were formed, a linear phase ramp applied, and data expanded and smoothed. Data phase was extracted to map control, label, and M0 magnitude image pixels to their undistorted locations, and images were rebinned to original size. All images were corrected for motion artifacts in FSL 5.0. pCASL images were registered to M0 images, and control and label images were subtracted to compute quantitative CBF maps. Results: pCASL image and CBF map distortions were removed by PLACE in all subjects. Corrected images conformed well to the anatomical T1-weighted reference image, and deviations in corrected CBF maps were evident. Conclusion: Eliminating pCASL distortion with PLACE can improve CBF quantification accuracy using minimal

  1. Renal blood flow using arterial spin labelling MRI and calculated filtration fraction in healthy adult kidney donors pre-nephrectomy and post-nephrectomy

    Energy Technology Data Exchange (ETDEWEB)

    Cutajar, Marica; Clark, Christopher A.; Gordon, Isky [University College London, Imaging and Biophysics Unit, Institute of Child Health, London (United Kingdom); Hilton, Rachel; Olsburgh, Jonathon [Renal Unit, Guy' s and St Thomas' NHS Foundation Trust, London (United Kingdom); Marks, Stephen D. [Great Ormond Street Hospital for Children NHS Foundation Trust, Department of Paediatric Nephrology, London (United Kingdom); Thomas, David L. [University College London, Department of Brain Repair and Rehabilitation, Institute of Neurology, London (United Kingdom); Banks, Tina [Great Ormond Street Hospital for Children NHS Foundation Trust, Department of Radiology, London (United Kingdom)

    2015-08-15

    Renal plasma flow (RPF) (derived from renal blood flow, RBF) and glomerular filtration rate (GFR) allow the determination of the filtration fraction (FF), which may have a role as a non-invasive renal biomarker. This is a hypothesis-generating pilot study assessing the effect of nephrectomy on renal function in healthy kidney donors. Eight living kidney donors underwent arterial spin labelling (ASL) magnetic resonance imaging (MRI) and GFR measurement prior to and 1 year after nephrectomy. Chromium-51 labelled ethylenediamine tetraacetic acid ({sup 51}Cr-EDTA) with multi-blood sampling was undertaken and GFR calculated. The RBF and GFR obtained were used to calculate FF. All donors showed an increase in single kidney GFR of 24 - 75 %, and all but two showed an increase in FF (-7 to +52 %) after nephrectomy. The increase in RBF, and hence RPF, post-nephrectomy was not as great as the increase in GFR in seven out of eight donors. As with any pilot study, the small number of donors and their relatively narrow age range are potential limiting factors. The ability to measure RBF, and hence RPF, non-invasively, coupled with GFR measurement, allows calculation of FF, a biomarker that might provide a sensitive indicator of loss of renal reserve in potential donors. (orig.)

  2. Renal blood flow using arterial spin labelling MRI and calculated filtration fraction in healthy adult kidney donors pre-nephrectomy and post-nephrectomy

    International Nuclear Information System (INIS)

    Cutajar, Marica; Clark, Christopher A.; Gordon, Isky; Hilton, Rachel; Olsburgh, Jonathon; Marks, Stephen D.; Thomas, David L.; Banks, Tina

    2015-01-01

    Renal plasma flow (RPF) (derived from renal blood flow, RBF) and glomerular filtration rate (GFR) allow the determination of the filtration fraction (FF), which may have a role as a non-invasive renal biomarker. This is a hypothesis-generating pilot study assessing the effect of nephrectomy on renal function in healthy kidney donors. Eight living kidney donors underwent arterial spin labelling (ASL) magnetic resonance imaging (MRI) and GFR measurement prior to and 1 year after nephrectomy. Chromium-51 labelled ethylenediamine tetraacetic acid ( 51 Cr-EDTA) with multi-blood sampling was undertaken and GFR calculated. The RBF and GFR obtained were used to calculate FF. All donors showed an increase in single kidney GFR of 24 - 75 %, and all but two showed an increase in FF (-7 to +52 %) after nephrectomy. The increase in RBF, and hence RPF, post-nephrectomy was not as great as the increase in GFR in seven out of eight donors. As with any pilot study, the small number of donors and their relatively narrow age range are potential limiting factors. The ability to measure RBF, and hence RPF, non-invasively, coupled with GFR measurement, allows calculation of FF, a biomarker that might provide a sensitive indicator of loss of renal reserve in potential donors. (orig.)

  3. Three-dimensional whole-brain perfusion quantification using pseudo-continuous arterial spin labeling MRI at multiple post-labeling delays: accounting for both arterial transit time and impulse response function.

    Science.gov (United States)

    Qin, Qin; Huang, Alan J; Hua, Jun; Desmond, John E; Stevens, Robert D; van Zijl, Peter C M

    2014-02-01

    Measurement of the cerebral blood flow (CBF) with whole-brain coverage is challenging in terms of both acquisition and quantitative analysis. In order to fit arterial spin labeling-based perfusion kinetic curves, an empirical three-parameter model which characterizes the effective impulse response function (IRF) is introduced, which allows the determination of CBF, the arterial transit time (ATT) and T(1,eff). The accuracy and precision of the proposed model were compared with those of more complicated models with four or five parameters through Monte Carlo simulations. Pseudo-continuous arterial spin labeling images were acquired on a clinical 3-T scanner in 10 normal volunteers using a three-dimensional multi-shot gradient and spin echo scheme at multiple post-labeling delays to sample the kinetic curves. Voxel-wise fitting was performed using the three-parameter model and other models that contain two, four or five unknown parameters. For the two-parameter model, T(1,eff) values close to tissue and blood were assumed separately. Standard statistical analysis was conducted to compare these fitting models in various brain regions. The fitted results indicated that: (i) the estimated CBF values using the two-parameter model show appreciable dependence on the assumed T(1,eff) values; (ii) the proposed three-parameter model achieves the optimal balance between the goodness of fit and model complexity when compared among the models with explicit IRF fitting; (iii) both the two-parameter model using fixed blood T1 values for T(1,eff) and the three-parameter model provide reasonable fitting results. Using the proposed three-parameter model, the estimated CBF (46 ± 14 mL/100 g/min) and ATT (1.4 ± 0.3 s) values averaged from different brain regions are close to the literature reports; the estimated T(1,eff) values (1.9 ± 0.4 s) are higher than the tissue T1 values, possibly reflecting a contribution from the microvascular arterial blood compartment

  4. Arterial spin-labeling perfusion imaging of childhood meningitis: a case series.

    Science.gov (United States)

    Wong, Alex Mun-Ching; Yeh, Chih-Hua; Liu, Ho-Ling; Lin, Kuang-Lin; Wang, Huei-Shyong; Toh, Cheng-Hong

    2016-03-01

    Conventional magnetic resonance imaging (MRI), which is mainly used to detect complications, is ineffective in determining the neurological status of patients with meningitis. Hemodynamic change in the brain may be more indicative of the neurological status but few imaging studies have verified this. Arterial spin-labeling (ASL) perfusion, a noninvasive MR method requiring no contrast agent injection, can be used to measure cerebral blood flow (CBF). We describe three pediatric patients with meningitis, who all showed regions of increased CBF on perfusion imaging. One patient, presenting with headache and conscious disturbance, had CBF changes in the frontal, temporal, and occipital regions. The other two patients, presenting with hallucinations, memory deficits, and seizures, had CBF changes in the frontal and temporal regions. ASL perfusion imaging may be helpful in assessing patients with meningitis, demonstrating CBF changes more strongly correlating with the neurological status, and detecting active brain abnormalities.

  5. Reliability of Three Dimentional Pseudo-continuous Arterial Spin Labeling: A Volumetric Cerebral Perfusion Imaging with Different Post-labeling Time and Functional State in Health Adults.

    Science.gov (United States)

    Liu, Meng-Qi; Chen, Zhi-Ye; Ma, Lin

    2018-03-30

    Objective To evaluate the reliability of three dimensional spiral fast spin echo pseudo-continuous arterial spin labeling (3D pc-ASL) in measuring cerebral blood flow (CBF) with different post-labeling delay time (PLD) in the resting state and the right finger taping state. Methods 3D pc-ASL and three dimensional T1-weighted fast spoiled gradient recalled echo (3D T1-FSPGR) sequence were applied to eight healthy subjects twice at the same time each day for one week interval. ASL data acquisition was performed with post-labeling delay time (PLD) 1.5 seconds and 2.0 seconds in the resting state and the right finger taping state respectively. CBF mapping was calculated and CBF value of both the gray matter (GM) and white matter (WM) was automatically extracted. The reliability was evaluated using the intraclass correlation coefficient (ICC) and Bland and Altman plot. Results ICC of the GM (0.84) and WM (0.92) was lower at PLD 1.5 seconds than that (GM, 0.88; WM, 0.94) at PLD 2.0 seconds in the resting state, and ICC of GM (0.88) was higher in the right finger taping state than that in the resting state at PLD 1.5 seconds. ICC of the GM and WM was 0.71 and 0.78 for PLD 1.5 seconds and PLD 2.0 seconds in the resting state at the first scan, and ICC of the GM and WM was 0.83 and 0.79 at the second scan, respectively. Conclusion This work demonstrated that 3D pc-ASL might be a reliable imaging technique to measure CBF over the whole brain at different PLD in the resting state or controlled state.

  6. Patterns of free amino acids in German convenience food products: marked mismatch between label information and composition.

    Science.gov (United States)

    Hermanussen, M; Gonder, U; Jakobs, C; Stegemann, D; Hoffmann, G

    2010-01-01

    Free amino acids affect food palatability. As information on amino acids in frequently purchased pre-packaged food is virtually absent, we analyzed free amino acid patterns of 17 frequently purchased ready-to-serve convenience food products, and compared them with the information obtained from the respective food labels. Quantitative amino acid analysis was performed using ion-exchange chromatography. gamma-Aminobutyric acid (GABA) concentrations were verified using a stable isotope dilution gas chromatography/mass spectrometry (GC-MS) method. The patterns of free amino acids were compared with information obtained from food labels. An obvious mismatch between free amino acid patterns and food label information was detected. Even on considering that tomatoes and cereal proteins are naturally rich in glutamate, the concentrations of free glutamate outranged the natural concentration of this amino acid in several products, and strongly suggested artificial enrichment. Free glutamate was found to be elevated even in dishes that explicitly state 'no glutamate added'. Arginine was markedly elevated in lentils. Free cysteine was generally low, possibly reflecting thermal destruction of this amino acid during food processing. The meat and brain-specific dipeptide carnosine (CARN) was present in most meat-containing products. Some products did not contain detectable amounts of CARN in spite of meat content being claimed on the food labels. We detected GABA at concentrations that contribute significantly to the taste sensation. This investigation highlights a marked mismatch between food label information and food composition.

  7. Labeling of antibodies with a 67Ga-phenolic aminocarboxylic acid chelate. Pt. 1

    International Nuclear Information System (INIS)

    Schuhmacher, J.; Matys, R.; Hauser, H.; Maier-Borst, W.; Matzku, S.

    1986-01-01

    As a chelating agent for labeling antibodies (Abs) with metallic radionuclides, a propionic acid substituted ethylenediamine N, N'-di-[(o-hydroxyphenyl) acetic acid] (P-EDDHA), which tighly complexes 67 Ga, was synthetized. The 67 Ga-P-EDDHA chelate was coupled in aqueous solution to IgG at a molar ratio of 1:1 via carbodiimide. The average coupling yield was 15%. A specific activity of 4 mCi/mg IgG could be obtained with commercially supplied 67 Ga. In vitro stability was evaluated in human serum at 37 0 C and showed a half-life of about 120 h for the release of 67 Ga from the labeled Ab during the initial phase of incubation. This in vitro halflife is similar to that measured for 111 In-DTPA labeled Abs. Because of the high stability of the 67 Ga-P-EDDHA chelate, the in vivo formation of radioactive lebeled transferrin by transchelation, as described for 111 In-DTPA labeled Abs, should, however, be reduced by this labeling technique. (orig.)

  8. Intra-arterial high signals on arterial spin labeling perfusion images predict the occluded internal carotid artery segment

    International Nuclear Information System (INIS)

    Sogabe, Shu; Satomi, Junichiro; Tada, Yoshiteru; Kanematsu, Yasuhisa; Kuwayama, Kazuyuki; Yagi, Kenji; Yoshioka, Shotaro; Mizobuchi, Yoshifumi; Mure, Hideo; Yamaguchi, Izumi; Kitazato, Keiko T.; Nagahiro, Shinji; Abe, Takashi; Harada, Masafumi; Yamamoto, Nobuaki; Kaji, Ryuji

    2017-01-01

    Arterial spin labeling (ASL) involves perfusion imaging using the inverted magnetization of arterial water. If the arterial arrival times are longer than the post-labeling delay, labeled spins are visible on ASL images as bright, high intra-arterial signals (IASs); such signals were found within occluded vessels of patients with acute ischemic stroke. The identification of the occluded segment in the internal carotid artery (ICA) is crucial for endovascular treatment. We tested our hypothesis that high IASs on ASL images can predict the occluded segment. Our study included 13 patients with acute ICA occlusion who had undergone angiographic and ASL studies within 48 h of onset. We retrospectively identified the high IAS on ASL images and angiograms and recorded the occluded segment and the number of high IAS-positive slices on ASL images. The ICA segments were classified as cervical (C1), petrous (C2), cavernous (C3), and supraclinoid (C4). Of seven patients with intracranial ICA occlusion, five demonstrated high IASs at C1-C2, suggesting that high IASs could identify stagnant flow proximal to the occluded segment. Among six patients with extracranial ICA occlusion, five presented with high IASs at C3-C4, suggesting that signals could identify the collateral flow via the ophthalmic artery. None had high IASs at C1-C2. The mean number of high IAS-positive slices was significantly higher in patients with intra- than extracranial ICA occlusion. High IASs on ASL images can identify slow stagnant and collateral flow through the ophthalmic artery in patients with acute ICA occlusion and help to predict the occlusion site. (orig.)

  9. Intra-arterial high signals on arterial spin labeling perfusion images predict the occluded internal carotid artery segment

    Energy Technology Data Exchange (ETDEWEB)

    Sogabe, Shu; Satomi, Junichiro; Tada, Yoshiteru; Kanematsu, Yasuhisa; Kuwayama, Kazuyuki; Yagi, Kenji; Yoshioka, Shotaro; Mizobuchi, Yoshifumi; Mure, Hideo; Yamaguchi, Izumi; Kitazato, Keiko T.; Nagahiro, Shinji [Tokushima University Graduate School, Department of Neurosurgery, Tokushima (Japan); Abe, Takashi; Harada, Masafumi [Tokushima University Graduate School, Department of Radiology, Tokushima (Japan); Yamamoto, Nobuaki; Kaji, Ryuji [Tokushima University Graduate School, Department of Clinical Neurosciences, Institute of Biomedical Biosciences, Tokushima (Japan)

    2017-06-15

    Arterial spin labeling (ASL) involves perfusion imaging using the inverted magnetization of arterial water. If the arterial arrival times are longer than the post-labeling delay, labeled spins are visible on ASL images as bright, high intra-arterial signals (IASs); such signals were found within occluded vessels of patients with acute ischemic stroke. The identification of the occluded segment in the internal carotid artery (ICA) is crucial for endovascular treatment. We tested our hypothesis that high IASs on ASL images can predict the occluded segment. Our study included 13 patients with acute ICA occlusion who had undergone angiographic and ASL studies within 48 h of onset. We retrospectively identified the high IAS on ASL images and angiograms and recorded the occluded segment and the number of high IAS-positive slices on ASL images. The ICA segments were classified as cervical (C1), petrous (C2), cavernous (C3), and supraclinoid (C4). Of seven patients with intracranial ICA occlusion, five demonstrated high IASs at C1-C2, suggesting that high IASs could identify stagnant flow proximal to the occluded segment. Among six patients with extracranial ICA occlusion, five presented with high IASs at C3-C4, suggesting that signals could identify the collateral flow via the ophthalmic artery. None had high IASs at C1-C2. The mean number of high IAS-positive slices was significantly higher in patients with intra- than extracranial ICA occlusion. High IASs on ASL images can identify slow stagnant and collateral flow through the ophthalmic artery in patients with acute ICA occlusion and help to predict the occlusion site. (orig.)

  10. A new label dosimetry system based on pentacosa-diynoic acid monomer for low dose applications

    International Nuclear Information System (INIS)

    Abdel-Fattah, A.A.; Abdel-Rehim, F.; Soliman, Y.S.

    2012-01-01

    The dosimetric characteristics of γ-radiation sensitive labels based on polyvinyl butyral (PVB) and a conjugated diacetylene monomer, 10,12-pentacosa-diynoic acid (PCDA) have been investigated using reflectance colorimeter. Two types of labels (colourless and yellow) based on PCDA monomer were prepared using an Automatic Film Applicator System. Upon γ-ray exposure, the colourless label turns progressively blue, while the yellow colour label turns to green then to dark blue. The colour intensity of the labels is proportional to the radiation absorbed dose. The useful dose range was 15 Gy-2 kGy depending on PCDA monomer concentration. The expanded uncertainty of dose measurement of the colourless label was 6.06 (2σ). - Highlights: → Using 10,12-pentacosa-diynoic acid (PCDA) in preparation of label dosimeter. → PCDA polymerises upon γ-rays exposure producing a blue coloured polymer. → Useful dose range is 15 Gy to 2 kGy depending on concentration of PCDA. → Overall uncertainty of label dosimeter was 6.06 at 2σ.

  11. Human absorbed dose calculations for 123I labeled phenyl pentadecanoic acid

    International Nuclear Information System (INIS)

    Kulkarni, P.V.; Clark, G.; Corbett, J.R.; Willerson, J.T.; Parkey, R.W.

    1986-01-01

    I-123 labeled fatty acids have been proposed for studying myocardial metabolism by scintigraphic methods. With the availability of clean I-123 and the advent of single photon emission tomography, I-123 labeled fatty acids would be well suited to study regional myocardial viability or metabolism in humans. The authors have studied I-125 and I-123 labeled iodophenyl pentadecanoic acid (IPPA) in rats and dogs. Clinical studies are in progress with I-123 (IPPA). They have studied the pharmacokinetics of this tracer in male Sprague-Dawley rats at 0.25, 0.5, 1, 3, 6, and 24 hours postinjection. The cumulated doses, due to both pure I-123 and a version contaminated with 1.4% I-125, in various organs and the total body in humans are estimated. The average dose to organs for humans injected with I-123 IPPA with pure I-123 and contaminated I-123 respectively, are (rads to organ per mCi injected): heart wall (0.0507, 0.0514), liver (0.0792, 0.0875), kidneys (0.0479, 0.0561), thyroid (0.0517, 0.0638), ovaries (0.0427, 0.0561), testes (0.0307, 0.0309), total body (0.0386, 0.0392). 12 references, 9 figures, 5 tables

  12. Arterial Spin Labeling and Blood Oxygen Level-Dependent MRI Cerebrovascular Reactivity in Cerebrovascular Disease

    DEFF Research Database (Denmark)

    Smeeing, Diederik P J; Hendrikse, Jeroen; Petersen, Esben T

    2016-01-01

    BACKGROUND: The cerebrovascular reactivity (CVR) results of blood oxygen level-dependent (BOLD) and arterial spin labeling (ASL) MRI studies performed in patients with cerebrovascular disease (steno-occlusive vascular disease or stroke) were systematically reviewed. SUMMARY: Thirty-one articles...... found a significant lower ASL CVR in the ipsilateral hemispheres of patients compared to controls. KEY MESSAGES: This review brings support for a reduced BOLD and ASL CVR in the ipsilateral hemisphere of patients with cerebrovascular disease. We suggest that future studies will be performed in a uniform...... way so reference values can be established and could be used to guide treatment decisions in patients with cerebrovascular disease....

  13. Demonstration of pulmonary perfusion heterogeneity induced by gravity and lung inflation using arterial spin labeling

    Energy Technology Data Exchange (ETDEWEB)

    Fan Li [Department of Radiology, ChangZheng Hospital, Second Military Medical University, Shanghai 200003 (China)], E-mail: fanli0930@163.com; Liu Shiyuan [Department of Radiology, ChangZheng Hospital, Second Military Medical University, Shanghai 200003 (China)], E-mail: fanli7938@chinaren.com; Xiao Xiangsheng [Department of Radiology, ChangZheng Hospital, Second Military Medical University, Shanghai 200003 (China)], E-mail: lizhaobin79@163.com; Sun Fei [GE Healthcare (China)], E-mail: Fei.sun@med.ge.com

    2010-02-15

    Objective: To evaluate the effect of gravity and lung inflation on pulmonary perfusion heterogeneity in human lung using an arterial spin labeling (ASL) sequence called flow sensitive alternating inversion recovery (FAIR). Materials and methods: Magnetic resonance imaging of lung perfusion using arterial spin labeling sequence was performed in supine position in ten healthy volunteers on a 1.5 T whole body scanner (GE Healthcare). Five coronal slices at an interval of 3 cm from dorsal to ventral (labeled as P3, P6, P9, P12, P15, sequently) were obtained when the volunteers performed breath holding on end expiration and the relative pulmonary blood flow (rPBF) was measured. Then, another coronal perfusion-weighted image of P3 slice was obtained on end inspiration. Tagging efficiency of pulmonary parenchyma with IR ({delta}SI), rPBF and area of the P3 slice were analyzed. Results: (1) Along the direction of gravity, a gradient was visually perceived as a vertical increase in rPBF. There were significant statistic differences in rPBF between any two coronal planes except that between P12 and P15. In supine position, regression coefficients of right and left lung were -4.98 and -5.16, respectively. This means that rPBF decreased 4.98 (right) and 5.16 (left) for each centimeter above the dorsal. No statistical difference was seen between ROIs placed along iso-gravitational plane. (2) For a same slice, there were significant statistic differences in {delta}SI, rPBF and area at different respiratory phases (P < 0.05). Greater {delta}SI and more perfusion were observed on end expiration than on end inspiration. The area was larger on end inspiration than on end expiration. Conclusion: Both gravity and respiratory phase are important determinants of pulmonary perfusion heterogeneity. FAIR is sensitive to demonstrate gravity- and respiratory phase-dependent differences in lung perfusion. Positioning the patient so that the area of interest is down-gravity and asking patient

  14. Electron paramagnetic resonance spin label titration: a novel method to investigate random and site-specific immobilization of enzymes onto polymeric membranes with different properties

    International Nuclear Information System (INIS)

    Butterfield, D. Allan; Colvin, Joshua; Liu Jiangling; Wang Jianquan; Bachas, Leonidas; Bhattacharrya, Dibakar

    2002-01-01

    The immobilization of biological molecules onto polymeric membranes to produce biofunctional membranes is used for selective catalysis, separation, analysis, and artificial organs. Normally, random immobilization of enzymes onto polymeric membranes leads to dramatic reduction in activity due to chemical reactions involved in enzyme immobilization, multiple-point binding, etc., and the extent of activity reduction is a function of membrane hydrophilicity (e.g. activity in cellulosic membrane >> polysulfone membrane). We have used molecular biology to effect site-specific immobilization of enzymes in a manner that orients the active site away from the polymeric membrane surface, thus resulting in higher enzyme activity that approaches that in solution and in increased stability of the enzyme relative to the enzyme in solution. A prediction of this site-specific method of enzyme immobilization, which in this study with subtilisin and organophosphorus hydrolase consists of a fusion tag genetically added to these enzymes and subsequent immobilization via the anti-tag antibody and membrane-bound protein A, is that the active site conformation will more closely resemble that of the enzyme in solution than is the case for random immobilization. This hypothesis was confirmed using a new electron paramagnetic resonance (EPR) spin label active site titration method that determines the amount of spin label bound to the active site of the immobilized enzyme. This value nearly perfectly matched the enzyme activity, and the results suggested: (a) a spectroscopic method for measuring activity and thus the extent of active enzyme immobilization in membrane, which may have advantages in cases where optical methods can not be used due to light scattering interference; (b) higher spin label incorporation (and hence activity) in enzymes that had been site-specifically immobilized versus random immobilization; (c) higher spin label incorporation in enzymes immobilized onto hydrophilic

  15. Radioactively labelled phytic acid from maturing seeds of sinapis alba

    International Nuclear Information System (INIS)

    Blaicher, F.M.; Mukherjee, K.D.

    1981-01-01

    Maturing seeds of Sinapis alba were incubated with D-[U- 14 C]glucose, sodium [1- 14 C] acetate or myo-[U 14 C] inositol in order to prepare radioactively labelled phytic acid with high specific activity. Although each substrate was utilized for the biosynthesis of phytic acid, maximum incorporation of radioactivity into phytic acid was found with myo-inositol. Radiochemical purity of the [U- 14 C]phytic acid preparations was confirmed by chromatographic techniques. Such preparations should be useful for the study of interaction of phytic acid with metal ions and proteins and may serve as substrate in the assay should be useful for the study of interaction of phytic acid with metal ions and proteins and may serve as substrate in the assay of phytase. (orig.)

  16. Arterial spin-labeling MR imaging of cerebral hemorrhages

    Energy Technology Data Exchange (ETDEWEB)

    Noguchi, Tomoyuki [Department of Radiology, National Center for Global Health and Medicine, Tokyo (Japan); Saga University, Department of Radiology, Faculty of Medicine and Graduate School of Medicine, Saga (Japan); Nishihara, Masashi; Egashira, Yoshiaki; Azama, Shinya; Hirai, Tetsuyoshi; Kitano, Isao; Irie, Hiroyuki [Saga University, Department of Radiology, Faculty of Medicine and Graduate School of Medicine, Saga (Japan); Yakushiji, Yusuke [Saga University, Department of Neurology, Faculty of Medicine and Graduate School of Medicine, Saga (Japan); Kawashima, Masatou [Saga University, Department of Neurosurgery, Faculty of Medicine and Graduate School of Medicine, Saga (Japan)

    2015-11-15

    The purpose of this study is to identify the characteristics of brain perfusion measured by arterial spin-labeling magnetic resonance imaging (ASL-MRI) in cerebral hemorrhages. Brain blood flow values (CBF-ASL values) for cerebral and cerebellar hemispheres and segmented cerebral regions were measured by ASL-MRI in 19 putaminal hemorrhage patients and 20 thalamic hemorrhage patients in acute or subacute stages. We assessed the lateralities of CBF-ASL values and the relationships between CBF-ASL values and other imaging findings and clinical manifestations. Both the 19 putaminal hemorrhage patients and the 20 thalamic hemorrhage patients had significantly low CBF-ASL values of the contralateral cerebellum in subacute stage, suggesting that ASL-MRI might delineate crossed cerebellar diaschisis (CCD). Ipsilateral low CBF-ASL values were observed in frontal lobes and thalami with a putaminal hemorrhage and lentiform nuclei, temporal lobes, and parietal lobes with a thalamic hemorrhage, suggesting that ASL-MRI showed the ipsilateral cerebral diaschisis (ICD). In the putaminal hemorrhage patients, the hematoma volume negatively affected both the bilateral cerebellar and cerebral hemispheric CBF-ASL values. In the thalamic hemorrhage patients, a concomitant intraventricular hemorrhage caused low cerebral hemispheric CBF-ASL values. The use of ASL-MRI is sensitive to the perfusion abnormalities and could thus be helpful to estimate functional abnormalities in cerebral hemorrhage patients. (orig.)

  17. Arterial spin-labeling MR imaging of cerebral hemorrhages

    International Nuclear Information System (INIS)

    Noguchi, Tomoyuki; Nishihara, Masashi; Egashira, Yoshiaki; Azama, Shinya; Hirai, Tetsuyoshi; Kitano, Isao; Irie, Hiroyuki; Yakushiji, Yusuke; Kawashima, Masatou

    2015-01-01

    The purpose of this study is to identify the characteristics of brain perfusion measured by arterial spin-labeling magnetic resonance imaging (ASL-MRI) in cerebral hemorrhages. Brain blood flow values (CBF-ASL values) for cerebral and cerebellar hemispheres and segmented cerebral regions were measured by ASL-MRI in 19 putaminal hemorrhage patients and 20 thalamic hemorrhage patients in acute or subacute stages. We assessed the lateralities of CBF-ASL values and the relationships between CBF-ASL values and other imaging findings and clinical manifestations. Both the 19 putaminal hemorrhage patients and the 20 thalamic hemorrhage patients had significantly low CBF-ASL values of the contralateral cerebellum in subacute stage, suggesting that ASL-MRI might delineate crossed cerebellar diaschisis (CCD). Ipsilateral low CBF-ASL values were observed in frontal lobes and thalami with a putaminal hemorrhage and lentiform nuclei, temporal lobes, and parietal lobes with a thalamic hemorrhage, suggesting that ASL-MRI showed the ipsilateral cerebral diaschisis (ICD). In the putaminal hemorrhage patients, the hematoma volume negatively affected both the bilateral cerebellar and cerebral hemispheric CBF-ASL values. In the thalamic hemorrhage patients, a concomitant intraventricular hemorrhage caused low cerebral hemispheric CBF-ASL values. The use of ASL-MRI is sensitive to the perfusion abnormalities and could thus be helpful to estimate functional abnormalities in cerebral hemorrhage patients. (orig.)

  18. Synthesis of 1- and 3-11C-labelled L-lactic acid using multi-enzyme catalysis

    International Nuclear Information System (INIS)

    Bjurling, P.; Laangstroem, B.

    1990-01-01

    The synthesis of 1- and 3- 11 C-labelled L-lactic acid from the corresponding racemic 1- or 3- 11 C-labelled alanine using a multi-enzymatic reaction route, is presented. DL-[1- 11 C]Alanine was synthesised by reacting sodium 1-hydroxy-ethyl sulfite with hydrogen [ 11 C]cyanide, obtained from [ 11 C]carbon dioxide, and ammonia followed by acid hydrolysis. DL-[3- 11 C]-Alanine was synthesised by a methylation of a glycine derivative, N-(diphenylmethylene)-glycine tert-butyl ester, with [ 11 C]methyl iodide, obtained from [ 11 C]carbon dioxide, and subsequent hydrolysis. The racemic 1- or 3- 11 C-labelled alanine was then converted to pyruvic acid, by D-amino acid oxidase/catalase and glutamic-pyruvic transaminase, which was directly reduced to L-lactic acid by L-lactic dehydrogenase in a one-pot procedure. The total synthesis time was 40 minutes, counted from release of [ 11 C]carbon dioxide. The decay corrected radiochemical yields were ca. 80% for L-[1- 11 C]lactic acid, based on hydrogen cyanide, and ca. 60% for L-[3- 11 C]lactic acid, based on carbon dioxide. The radiochemical purities were higher than 99% analysed by HPLC. (author)

  19. Larmor labeling by time-gradient magnetic fields

    International Nuclear Information System (INIS)

    Ioffe, Alexander; Bodnarchuk, Victor; Bussmann, Klaus; Mueller, Robert

    2007-01-01

    The Larmor labeling of neutrons, due to the Larmor precession of neutron spin in a magnetic field, opens the unique possibility for the development of neutron spin-echo (NSE) based on neutron scattering techniques, featuring an extremely high energy (momentum) resolution. Here, we present the experimental proof of a new method of the Larmor labeling using time-gradient magnetic fields

  20. N-15-labelled pyrazines of triterpenic acids

    Czech Academy of Sciences Publication Activity Database

    Vlk, M.; Mičolová, P.; Urban, M.; Kvasnica, Miroslav; Šaman, David; Šarek, J.

    2016-01-01

    Roč. 308, č. 2 (2016), s. 733-739 ISSN 0236-5731 R&D Projects: GA ČR GJ15-08202Y; GA MŠk(CZ) LO1304; GA MŠk(CZ) LO1204 Grant - others:GA MŠk(CZ) LK21310; GA TA ČR(CZ) TA03010027; CTU(CZ) SGS15/094/OHK4/1T/14 Institutional support: RVO:61389030 ; RVO:61388963 Keywords : N-15 * Triterpenic acid * Isotopic labelling Subject RIV: CC - Organic Chemistry Impact factor: 1.282, year: 2016

  1. Isolation of 14C labelled amino acids by biosynthesis in maize plants (Zea mais L.)

    International Nuclear Information System (INIS)

    Carreras, N.; Mazon, M.P.

    1983-01-01

    A method of obtaining 14 C labelled amino acids by biosynthesis in maize plants which had assimilated 14CO 2 , has been assayed. The plants were labelled for 60 minutes with 14 C O2 produced from Ba 14 C O3 (specific activity of 148 KBq/μmol). An extract of the soluble compounds was obtained with 80% ethanol and the amino acids were separated from the rest of the soluble compounds by ion exchange chromatography on column of Dowex 50-X8 resin. Finally, seventeen amino acids were isolated and identified from the purified extract. The acid amino acids were separated in anionic column (Dowex 1-X8) and the neutral and basic amino acids in cationic column (Dowex 50-X4). (Author) 56 refs

  2. Isolation of carbon 14 labelled amino acids by biosynthesis in maize plants (zea mais L.)

    International Nuclear Information System (INIS)

    Carreras, N.; Mazon, M.P.

    1983-01-01

    A method of obtaining 14 C labelled amino acids by biosynthesis in maize plants which had assimilated 14 CO 2 , has been assayed. The plants were labelled for 60 minutes with 14 CO 2 produced from Ba 14 CO 3 (specific activity of 148 KBq/μmol). An extract of the soluble compounds was obtained with 80% ethanol and the amino acids were separated from the rest of the soluble compounds by ion exchange chromatography on column of Dowex 50-X8 resin. Finally, seventeen amino acids were isolated and identified from the purified extract. The acid amino acids were separated in anionic column (Dowex 1-X8) and the neutral and basic amino acids in cationic columns (Dowex 50-X4). (author)

  3. An acridinium sulphonylamide as a new chemiluminescent label for the determination of carboxylic acids in liquid chromatography

    NARCIS (Netherlands)

    Steijger, O.M.; Kamminga, D.A.; Lingeman, H.; Brinkman, U.A.T.

    1998-01-01

    The synthesis of a new acridinium sulphonylamide label for the liquid chromatographic determination of carboxylic acids is described. The label 10-methyl-N-(p-tolyl)-N-(p-iodoacetamidobenzenesulphonyl)-9-acridinium carboxamide iodide is synthesized from 9-acridinecarboxylic acid by a seven-step

  4. Displacement of carbon-14 labelled amino acids from leaves

    International Nuclear Information System (INIS)

    Schiller, R.

    1973-01-01

    The displacement of amino acids from nature leaves was investigated. The amino acids (Ala, Asn, Asp, Glu, Gln, Val, Leu, Lys, Ser, Pro) were applied on the leaves in L-form, uniformly labelled with 14 C, and the type and direction of displacement have been observed. Most of the studies have been carried out on bush beans aged 3 to 4 weeks. The experiments were carried out in climatic chambers; in one case, barley plants just reaching maturity were used. In order to find out whether the applied amino acids were also displaced in their original form, freeze-dried plants were extracted and the 14 C activity of the various fraction was determined. The radioactivity of some free amino acids was determined after two-dimensional separation by thin film chromatography. (orig./HK) [de

  5. Protein rotational dynamics investigated with a dual EPR/optical molecular probe. Spin-labeled eosin.

    Science.gov (United States)

    Cobb, C E; Hustedt, E J; Beechem, J M; Beth, A H

    1993-01-01

    An acyl spin-label derivative of 5-aminoeosin (5-SLE) was chemically synthesized and employed in studies of rotational dynamics of the free probe and of the probe when bound noncovalently to bovine serum albumin using the spectroscopic techniques of fluorescence anisotropy decay and electron paramagnetic resonance (EPR) and their long-lifetime counterparts phosphorescence anisotropy decay and saturation transfer EPR. Previous work (Beth, A. H., Cobb, C. E., and J. M. Beechem, 1992. Synthesis and characterization of a combined fluorescence, phosphorescence, and electron paramagnetic resonance probe. Society of Photo-Optical Instrumentation Engineers. Time-Resolved Laser Spectroscopy III. 504-512) has shown that the spin-label moiety only slightly altered the fluorescence and phosphorescence lifetimes and quantum yields of 5-SLE when compared with 5-SLE whose nitroxide had been reduced with ascorbate and with the diamagnetic homolog 5-acetyleosin. In the present work, we have utilized time-resolved fluorescence anisotropy decay and linear EPR spectroscopies to observe and quantitate the psec motions of 5-SLE in solution and the nsec motions of the 5-SLE-bovine serum albumin complex. Time-resolved phosphorescence anisotropy decay and saturation transfer EPR studies have been carried out to observe and quantitate the microseconds motions of the 5-SLE-albumin complex in glycerol/buffer solutions of varying viscosity. These latter studies have enabled a rigorous comparison of rotational correlation times obtained from these complementary techniques to be made with a single probe. The studies described demonstrate that it is possible to employ a single molecular probe to carry out the full range of fluorescence, phosphorescence, EPR, and saturation transfer EPR studies. It is anticipated that "dual" molecular probes of this general type will significantly enhance capabilities for extracting dynamics and structural information from macromolecules and their functional

  6. Radioactively labelled phytic acid from maturing seeds of Sinapis alba

    Energy Technology Data Exchange (ETDEWEB)

    Blaicher, F.M.; Mukherjee, K.D.

    Maturing seeds of Sinapis alba were incubated with D-(U-/sup 14/C)glucose, sodium (1-/sup 14/C) acetate or myo-(U/sup 14/C) inositol in order to prepare radioactively labelled phytic acid with high specific activity. Although each substrate was utilized for the biosynthesis of phytic acid, maximum incorporation of radioactivity into phytic acid was found with myo-inositol. Radiochemical purity of the (U-/sup 14/C)phytic acid preparations was confirmed by chromatographic techniques. Such preparations should be useful for the study of interaction of phytic acid with metal ions and proteins and may serve as substrate in the assay should be useful for the study of interaction of phytic acid with metal ions and proteins and may serve as substrate in the assay of phytase.

  7. Dynamic nuclear spin polarization

    Energy Technology Data Exchange (ETDEWEB)

    Stuhrmann, H B [GKSS-Forschungszentrum Geesthacht GmbH (Germany)

    1996-11-01

    Polarized neutron scattering from dynamic polarized targets has been applied to various hydrogenous materials at different laboratories. In situ structures of macromolecular components have been determined by nuclear spin contrast variation with an unprecedented precision. The experiments of selective nuclear spin depolarisation not only opened a new dimension to structural studies but also revealed phenomena related to propagation of nuclear spin polarization and the interplay of nuclear polarisation with the electronic spin system. The observation of electron spin label dependent nuclear spin polarisation domains by NMR and polarized neutron scattering opens a way to generalize the method of nuclear spin contrast variation and most importantly it avoids precontrasting by specific deuteration. It also likely might tell us more about the mechanism of dynamic nuclear spin polarisation. (author) 4 figs., refs.

  8. Spin-labelled derivatives of cardiotonic steroids as tools for characterization of the extracellular entrance to the Na+ ,K+ -ATPase binding site.

    Science.gov (United States)

    Guo, Jin-Hua; Jiang, Ren-Wang; Andersen, Jacob Lauwring; Esmann, Mikael; Fedosova, Natalya U

    2018-04-24

    The information obtained from crystallized complexes of the Na + ,K + -ATPase with cardiotonic steroids (CTS) is not sufficient to explain differences in the inhibitory properties of CTS such as stereoselectivity of CTS-binding or effect of glycosylation on the preference to enzyme isoforms. The uncertainty is related to the spacial organization of the hydrophilic cavity at the entrance of the CTS-binding site. Therefore, there is a need to supplement the crystallographic description with data obtained in aqueous solution, where molecules have significant degree of flexibility. This work addresses the applicability of the electron paramagnetic resonance (EPR) method for the purpose. We have designed and synthesized spin-labelled compounds based on the cinobufagin steroid core. The length of the spacer arms between the steroid core and the nitroxide group determines the position of the reporting group (N-O) confined to the binding site. High affinity to Na + ,K + -ATPase is inferred from their ability to inhibit enzymatic activity. The differences between the EPR spectra in the absence and presence of high ouabain concentrations identify the signature peaks originating from the fraction of the spin-labels bound within the ouabain site. The degree of perturbations of the EPR spectra depends on the length of the spacer arm. Docking of the compounds into the CTS-site suggests which elements of the protein structure might be responsible for interference with the spin-label (e.g. steric clashes or immobilization). Thus, the method is suitable for gathering information on the cavity leading to the CTS-binding site in Na + ,K + -ATPase in all conformations with high affinity to CTS. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  9. Development of a facile and sensitive HPLC-FLD method via fluorescence labeling for triterpenic acid bioavailability investigation.

    Science.gov (United States)

    You, Jinmao; Wu, Di; Zhao, Mei; Li, Guoliang; Gong, Peiwei; Wu, Yueyue; Guo, Yu; Chen, Guang; Zhao, Xianen; Sun, Zhiwei; Xia, Lian; Wu, Yongning

    2017-06-01

    Triterpenic acids are widely distributed in many fruits and are known for their medicinal benefits. The study of bioavailability has been an important task for a better understanding of the triterpenic acids. Although many methods based on fluorescence labeling for triterpenic acid determination have been established, these reported methods needed anhydrous conditions, which are not suitable for the convenient study of triterpenic acid bioavailability. Inspired by that, a versatile method, which overcomes the difficulty of the reported methods, has been first developed in this study. The novel method using 2-[12-benzo[b]acridin-5- (12H)-yl]-acetohydrazide (BAAH) as the fluorescence labeling reagent coupled with high-performance liquid chromatography with fluorescence detection was first developed for the study of triterpenic acid bioavailability. Furthermore, the labeling conditions have been optimized in order to achieve the best fluorescence labeling yield. Under the optimal conditions, the quantitative linear range of analytes was 2-1000 ng mL -1 , and the correlation coefficients were >0.9998. The detection limits for all triterpenic acid derivatives were achieved within the range of 0.28-0.29 ng mL -1 . The proposed method was successfully applied to the study of triterpenic acid bioavailability with excellent applicability and good reproducibility. Copyright © 2016 John Wiley & Sons, Ltd.

  10. First improvements in the detection and quantification of label-free nucleic acids by laser-induced breakdown spectroscopy: Application to the deoxyribonucleic acid micro-array technology

    International Nuclear Information System (INIS)

    Le Meur, Julien; Menut, Denis; Wodling, Pascal; Salmon, Laurent; Thro, Pierre-Yves; Chevillard, Sylvie; Ugolin, Nicolas

    2008-01-01

    The accurate quantification of nucleic acids is essential in many fields of modern biology and industry, and in some cases requires the use of fluorescence labeling. Yet, in addition to standardization problems and quantification reproducibility, labeling can modify the physicochemical properties of molecules or affect their stability. To address these limitations, we have developed a novel method to detect and quantify label-free nucleic acids. This method is based on stoichiometric proportioning of phosphorus in the nucleic acid skeleton, using laser-induced breakdown spectroscopy, and a specific statistical analysis, which indicates the error probability for each measurement. The results obtained appear to be quantitative, with a limit of detection of 10 5 nucleotides/μm 2 (i.e. 2 x 10 13 phosphorus atoms/cm 2 ). Initial micro-array analysis has given very encouraging results, which point to new ways of quantifying hybridized nucleic acids. This is essential when comparing molecules of different sequences, which is presently very difficult with fluorescence labeling

  11. First improvements in the detection and quantification of label-free nucleic acids by laser-induced breakdown spectroscopy: Application to the deoxyribonucleic acid micro-array technology

    Energy Technology Data Exchange (ETDEWEB)

    Le Meur, Julien [Laboratoire de Cancerologie Experimentale, Commissariat a l' Energie Atomique de Fontenay-aux-Roses, Direction des Sciences du Vivant, Departement de Radiobiologie et Radiopathologie, Fontenay-aux-Roses (France); Menut, Denis [Laboratoire de Reactivite des Surfaces et des Interfaces, Commissariat a l' Energie Atomique de Saclay, Direction de l' Energie Nucleaire, Departement de Physico-Chimie, Gif sur Yvette (France); Wodling, Pascal [Laboratoire d' Interaction Laser-Matiere, Commissariat a l' Energie Atomique de Saclay, Direction de l' Energie Nucleaire, Departement de Physico-Chimie, Gif sur Yvette (France); Salmon, Laurent [Laboratoire de Reactivite des Surfaces et des Interfaces, Commissariat a l' Energie Atomique de Saclay, Direction de l' Energie Nucleaire, Departement de Physico-Chimie, Gif sur Yvette (France); Thro, Pierre-Yves [Laboratoire d' Interaction Laser-Matiere, Commissariat a l' Energie Atomique de Saclay, Direction de l' Energie Nucleaire, Departement de Physico-Chimie, Gif sur Yvette (France); Chevillard, Sylvie [Laboratoire de Cancerologie Experimentale, Commissariat a l' Energie Atomique de Fontenay-aux-Roses, Direction des Sciences du Vivant, Departement de Radiobiologie et Radiopathologie, Fontenay-aux-Roses (France); Ugolin, Nicolas [Laboratoire de Cancerologie Experimentale, Commissariat a l' Energie Atomique de Fontenay-aux-Roses, Direction des Sciences du Vivant, Departement de Radiobiologie et Radiopathologie, Fontenay-aux-Roses (France)], E-mail: nugolin@cea.fr

    2008-04-15

    The accurate quantification of nucleic acids is essential in many fields of modern biology and industry, and in some cases requires the use of fluorescence labeling. Yet, in addition to standardization problems and quantification reproducibility, labeling can modify the physicochemical properties of molecules or affect their stability. To address these limitations, we have developed a novel method to detect and quantify label-free nucleic acids. This method is based on stoichiometric proportioning of phosphorus in the nucleic acid skeleton, using laser-induced breakdown spectroscopy, and a specific statistical analysis, which indicates the error probability for each measurement. The results obtained appear to be quantitative, with a limit of detection of 10{sup 5} nucleotides/{mu}m{sup 2} (i.e. 2 x 10{sup 13} phosphorus atoms/cm{sup 2}). Initial micro-array analysis has given very encouraging results, which point to new ways of quantifying hybridized nucleic acids. This is essential when comparing molecules of different sequences, which is presently very difficult with fluorescence labeling.

  12. A novel medium for expression of proteins selectively labeled with 15N-amino acids in Spodoptera frugiperda (Sf9) insect cells

    International Nuclear Information System (INIS)

    Brueggert, Michael; Rehm, Till; Shanker, Sreejesh; Georgescu, Julia; Holak, Tad A.

    2003-01-01

    Whereas bacterial expression systems are widely used for production of uniformly or selectively 15 N-labeled proteins the usage of the baculovirus expression system for labeling is limited to very few examples in the literature. Here we present the complete formulations of the two insect media, IML406 and 455, for the high-yield production of selectively 15 N-labeled proteins in insect cells. The quantities of 15 N-amino acids utilized in the production of labeled GST were similar in the case of bacterial and viral expression. For the most studied amino acids essential for insect cells the 15 N-HSQC spectra, recorded with GST labeled in insect cells, showed no cross labeling and provided therefore spectra of better quality compared to NMR spectra of GST expressed in E. coli. Also in the case of amino acids not essential for Sf9 cells we were able to label a defined number of amino acid species. Therefore the selective labeling using the baculovirus expression vector system represents a complement or even an alternative to the bacterial expression system. Based on these findings we can provide a first simple overview of the network of the amino acid metabolism in E. coli and insect cells focused on nitrogen. For some amino acids the expression of labeled proteins in insect cells can replace the cell-free protein expression

  13. Identification of a 23 kDa protein from maize photoaffinity-labelled with 5-azido-[7-3H]indol-3-ylacetic acid.

    OpenAIRE

    Feldwisch, J; Zettl, R; Campos, N; Palme, K

    1995-01-01

    A 23 kDa protein (p23) was identified in microsomal extracts from maize coleoptiles by photoaffinity labelling with 5-azido-[7-3H]indol-3-ylacetic acid ([3H]N3IAA). Labelling of p23 was blocked by unlabelled IAA, N3IAA, indol-3-ylbutyric acid and indol-3-yl-lactate. In addition, labelling was efficiently decreased by tryptophan, as well as by the scavenger p-aminobenzoic acid. Labelling was, however, not affected by synthetic auxins such as 1-naphthylacetic acid or 2,4-dichlorophenoxyacetic a...

  14. Synthesis and optical properties of pyrrolidinyl peptide nucleic acid carrying a clicked Nile red label

    Directory of Open Access Journals (Sweden)

    Nattawut Yotapan

    2014-09-01

    Full Text Available DNA or its analogues with an environment-sensitive fluorescent label are potentially useful as a probe for studying the structure and dynamics of nucleic acids. In this work, pyrrolidinyl peptide nucleic acid (acpcPNA was labeled at its backbone with Nile red, a solvatochromic benzophenoxazine dye, by means of click chemistry. The optical properties of the Nile red-labeled acpcPNA were investigated by UV–vis and fluorescence spectroscopy in the absence and in the presence of DNA. In contrast to the usual quenching observed in Nile red-labeled DNA, the hybridization with DNA resulted in blue shifting and an enhanced fluorescence regardless of the neighboring bases. More pronounced blue shifts and fluorescence enhancements were observed when the DNA target carried a base insertion in close proximity to the Nile red label. The results indicate that the Nile red label is located in a more hydrophobic environment in acpcPNA–DNA duplexes than in the single-stranded acpcPNA. The different fluorescence properties of the acpcPNA hybrids of complementary DNA and DNA carrying a base insertion are suggestive of different interactions between the Nile red label and the duplexes.

  15. A Study on Labelling of Linolenic Acid as A Model of Isolated Benalu Teh for Cancer Diagnosis with Iodine-131

    International Nuclear Information System (INIS)

    Isti Daruwati; Eva Maria Widyasari; Nanny Kartini Oekar

    2009-01-01

    A study on active fraction of benalu teh has been carried out at Center for Application of Isotope and Radiation Technology - BATAN. This benalu teh active fraction has inhibition capability about 99% to the cancer cell. The isolated fraction is octadeca-8,10,12-triyonic acid compound which have long chain unsaturated fatty acid compound with three triple bonds. The Benalu teh active fraction has similar structure with linolenic acid which is a long chain unsaturated fatty acid with three triple bonds. Based on this similarity, the study of labelling of linolenic acid with iodine-131 has been conducted. The research was focused on optimum conditions for labelling of linolenic acid using Iodine-131 radionuclide. Labelling with iodine-131 was conducted using KIO 3 as an oxidizing agent, which can additionated linolenic acid and sodium metabisulfite for ending the reaction. Labelling efficiency determination was conducted using paper chromatography technique. The result showed that the optimum condition achieved by using KIO 3 as an oxidizing agent that gave radiochemical purity of 99,44% in virgin coconut oil, and labelling efficiency of about 69,9%. The labelled compound has high radiochemical purity i.e 96,85% in chloroform and 98,33% virgin coconut oil that was stable until 10 days in refrigerator. (author)

  16. Label-free amino acid detection based on nanocomposites of graphene oxide hybridized with gold nanoparticles.

    Science.gov (United States)

    Zhang, Qian; Zhang, Diming; Lu, Yanli; Xu, Gang; Yao, Yao; Li, Shuang; Liu, Qingjun

    2016-03-15

    Nanocomposites of graphene oxide and gold nanoparticles (GO/GNPs) were synthesized for label-free detections of amino acids. Interactions between the composites and amino acids were investigated by both naked-eye observation and optical absorption spectroscopy. The GO/GNPs composites displayed apparent color changes and absorption spectra changes in presences of amino acids including glutamate, aspartate, and cysteine. The interaction mechanisms of the composites and amino acids were discussed and explored with sulfhydryl groups and non-α-carboxylic groups on the amino acids. Sensing properties of the composites were tested, while pure gold particles were used as the control. The results suggested that the GO/GNPs composites had better linearity and stability in dose-dependent responses to the amino acids than those of the particles, especially in detections for acidic amino acids. Therefore, the nanocomposites platform can provide a convenient and efficient approach for label-free optical detections of important molecules such as amino acids. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Preliminary studies of 99mTc labeled fatty acid analogs for myocardial imaging

    International Nuclear Information System (INIS)

    Guo Yuzhi; Kung, H.F.; Mack, R.H.

    1988-01-01

    Radio iodine labelled fatty acid analogs are potential myocardial imaging agents for SPECT. In this paper are reported three new 99m Tc labbeled fatty acid analogs: 9 '9 m Tc-BAT-TDA, 99m Tc-BAT-PDA and 99m Tc-BAT-H x DA. Ligand exchange reaction with 99m Tc stannous glucoheptonate in 50% aqueous ethanol is used for labelling. The yield of reactions is 87%, 70%, 49% respectively. 99m Tc-fatty acid is purified by extraction into chloroform and the purity as determined by reverse phase HPLC is 98%. In order to determine the structure of Tc-BAT-fatty acid, 99 Tc-BAT-PDA is synthesized with 99 Tc ammonium pertechnetate in 50% citric acid buffer (pH=6)/ethanol using stannous chloride as the reducing agent. 99 Tc-BAT-PDA displays the expected Tc=O UV absorption at 420nm and strong peak at 900cm -1 in the FTIR spectrum. Biodistribution studies of three 99m Tc-fatty acid analogs are conducted in rats using 125 I-ω- (p-iodophenyl) -penta-decanoic acid (IPPDA) as internal standard. The initial heart uptake of them is significantly lower than that of 125 I-IPPDA

  18. Synthesis of novel 68Ga-labeled amino acid derivatives for positron emission tomography of cancer cells

    International Nuclear Information System (INIS)

    Shetty, Dinesh; Jeong, Jae Min; Ju, Chang Hwan; Lee, Yun-Sang; Jeong, Seo Young; Choi, Jae Yeon; Yang, Bo Yeun

    2010-01-01

    Objectives: We developed amino acid derivatives of 1,4,7,10-tetraazacyclododecane-1,7-diacetic acid (DO2A) and 1,4,7,10-tetraazacyclododecane-1,4,7,-triacetic acid (DO3A) that can be labeled with 68 Ga, and we investigated their basic biological properties. Materials and methods: Alanine derivatives of DO2A and DO3A were synthesized by regiospecific nucleophilic attack of DO2tBu and DO3tBu on the β-position of Boc-L-serine-β-lactone, followed by acid hydrolysis. Also, homoalanine derivatives were synthesized by reacting with the protected bromo derivative of homoalanine, which was synthesized from N-Cbz-L-homoserine lactone. Further catalytic reduction and acid cleavage of protected groups resulted in the required products. All derivatives were labeled with 68 Ga. Cell uptake assays were carried out in Hep3B (human hepatoma) and U87MG (human glioma) cell lines at 37 o C. Positron emission tomography (PET) imaging studies were performed using balb/c mice xenografted with CT-26 (mouse colon cancer). Results: All compounds were labeled with >97% efficiency. According to in vitro studies, the labeled amino acid derivatives showed significantly greater uptakes than the control ( 68 Ga 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) in cancer cells. Small animal PET images for labeled compounds showed high tumor uptake, as well as kidney and bladder uptakes, at 30 min postinjection. 68 Ga-DO3A-homoalanine showed the highest standardized uptake value ratio (3.9±0.3), followed by 68 Ga-DO2A-alanine (3.1±0.2), 68 Ga-DO3A-alanine (2.8±0.2) and 68 Ga-DO2A-homoalanine (2.3±0.2). Conclusion: These derivatives were found to have high labeling efficiencies, high stabilities, high tumor cell uptakes, high tumor/nontumor xenograft uptakes and low nonspecific uptake in normal organs, except for the kidneys. However, the uptake mechanism of these derivatives remains unclear, and uptake via specific amino acid transporters needs to be demonstrated.

  19. Effect of impaired fatty acid oxidation on myocardial kinetics of 11C- and 123I-labelled fatty acids

    International Nuclear Information System (INIS)

    Lerch, R.

    1986-01-01

    Positron emission tomography with palmitate 11 C and single photon imaging with terminally radioiodinated fatty acid analogues (FFA 123 I) were evaluated for the noninvasive assessment of regional myocardial fatty acid metabolism during ischaemia. Decreased uptake of tracer and delayed clearance of activity in the ischaemic myocardium were reported for both 11 C- and 123 I-labelled compounds. However, since during ischaemia both myocardial blood flow and oxidative metabolism are reduced concomitantly, either factor can be responsible for the changes observed. Experimental preparations in which fatty acid metabolism can be modified independently of flow are helpful for the characterization of the relationship between metabolism and myocardial kinetics of labelled fatty acids. Results obtained during flow-independent inhibition of fatty acid oxidation include the following observations: - In dogs with controlled coronary perfusion the rate of clearance of palmitate 11 C-activity is decreased during diminished delivery of oxygen, regardless of whether myocardial perfusion is concomitantly reduced or not. - In isolated rabbit hearts perfused at normal flow, the extraction of FFA 123 I is decreased during hypoxia. - During pharmacological inhibition of fatty acid oxidation the deiodination of FFA 123 I is markedly reduced in rat hearts in vivo and in vitro. (orig.)

  20. Fatty acid biomarkers: validation of food web and trophic markers using C-13-labelled fatty acids in juvenile sandeel ( Ammodytes tobianus )

    DEFF Research Database (Denmark)

    Dalsgaard, Anne Johanne Tang; St. John, Michael

    2004-01-01

    A key issue in marine science is parameterizing trophic interactions in marine food webs, thereby developing an understanding of the importance of top-down and bottom-up controls on populations of key trophic players. This study validates the utility of fatty acid food web and trophic markers usi......), respectively. Lack of temporal trends in nonlabelled fatty acids confirmed the conservative incorporation of labelled fatty acids by the fish.......A key issue in marine science is parameterizing trophic interactions in marine food webs, thereby developing an understanding of the importance of top-down and bottom-up controls on populations of key trophic players. This study validates the utility of fatty acid food web and trophic markers using...... C-13-labelled fatty acids to verify the conservative incorporation of fatty acid tracers by juvenile sandeel (Ammodytes tobianus) and assess their uptake, clearance, and metabolic turnover rates. Juvenile sandeel were fed for 16 days in the laboratory on a formulated diet enriched in (13)C16...

  1. Improving perfusion quantification in arterial spin labeling for delayed arrival times by using optimized acquisition schemes

    International Nuclear Information System (INIS)

    Kramme, Johanna; Diehl, Volker; Madai, Vince I.; Sobesky, Jan; Guenther, Matthias

    2015-01-01

    The improvement in Arterial Spin Labeling (ASL) perfusion quantification, especially for delayed bolus arrival times (BAT), with an acquisition redistribution scheme mitigating the T1 decay of the label in multi-TI ASL measurements is investigated. A multi inflow time (TI) 3D-GRASE sequence is presented which adapts the distribution of acquisitions accordingly, by keeping the scan time constant. The MR sequence increases the number of averages at long TIs and decreases their number at short TIs and thus compensating the T1 decay of the label. The improvement of perfusion quantification is evaluated in simulations as well as in-vivo in healthy volunteers and patients with prolonged BATs due to age or steno-occlusive disease. The improvement in perfusion quantification depends on BAT. At healthy BATs the differences are small, but become larger for longer BATs typically found in certain diseases. The relative error of perfusion is improved up to 30% at BATs > 1500 ms in comparison to the standard acquisition scheme. This adapted acquisition scheme improves the perfusion measurement in comparison to standard multi-TI ASL implementations. It provides relevant benefit in clinical conditions that cause prolonged BATs and is therefore of high clinical relevance for neuroimaging of steno-occlusive diseases.

  2. The development of iodine-123-labeled-methyl-branched fatty acids for myocardial SPECT imaging

    International Nuclear Information System (INIS)

    Knapp, F.F. Jr.; Kropp, J.

    1994-01-01

    Iodine-123-labeled fatty acids represent unique metabolic probes for correlation of energy substrate metabolism with regional myocardial viability. Interest in the use of these agents results from differences which are often observed in various types of heart disease between regional myocardial fatty acid uptake patterns and flow tracer distribution. Although the physiological basis is not completely understood, differences between regional fatty acid and flow tracer distribution may reflect alterations in important parameters of metabolism which can be useful for patient management or therapeutic strategy decision making. The iodine-123-labeled 15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) fatty acid analogue was developed at the Oak Ridge National Laboratory and was recently introduced as ''Cardiodine trademark'' in 1993 by Nihon Medi-Physics for commercial distribution in Japan. Iodine-123-BMPP is also being used in clinical studies on an institutional approval basis at several institutions in Europe and the US. This paper describes the development of the concept of fatty acid ''metabolic trapping'' of methyl-branched fatty acids and their use for single photon emission computerized tomographic cardiac imaging

  3. Method to produce an I labelled fatty acid to be used as radiopharmaceutical

    International Nuclear Information System (INIS)

    Feinendegen, L.E.; Freundlieb, C.; Hoeck, A.; Machulla, J.; Stoecklin, G.; Vyska, K.

    1981-01-01

    The labelled fatty acids are used to investigate the circulation disturbances of the myocardium and the disturbance of the lipocatabolism in the myocardium. The activity is measured by an Anger camera. The fatty acid is obtained from -bromium fatty acid and separated chromatographically from the residual process products. Silica gel is used as separation column and a mixture of an alkane and addition of a polar acid solution, as carrier liquid. (orig./PW)

  4. Spontaneous transfer of stearic acids between human serum albumin and PEG:2000-grafted DPPC membranes.

    Science.gov (United States)

    Pantusa, Manuela; Stirpe, Andrea; Sportelli, Luigi; Bartucci, Rosa

    2010-05-01

    Electron spin resonance (ESR) spectroscopy is used to study the transfer of stearic acids between human serum albumin (HSA) and sterically stabilized liposomes (SSL) composed of dipalmitoylphosphatidylcholine (DPPC) and of submicellar content of poly(ethylene glycol:2000)-dipalmitoylphosphatidylethanolamine (PEG:2000-DPPE). Protein/lipid dispersions are considered in which spin-labelled stearic acids at the 16th carbon atom along the acyl chain (16-SASL) are inserted either in the protein or in the SSL. Two component ESR spectra with different rotational mobility are obtained over a broad range of temperature and membrane composition. Indeed, superimposed to an anisotropic protein-signal, appears a more isotropic lipid-signal. Since in the samples only one matrix (protein or membranes) is spin-labelled, the other component accounts for the transfer of 16-SASL between albumin and membranes. The two components have been resolved and quantified by spectral subtractions, and the fraction, f (p) (16-SASL), of spin labels bound non-covalently to the protein has been used to monitor the transfer. It is found that it depends on the type of donor and acceptor matrix, on the physical state of the membranes and on the grafting density of the polymer-lipids. Indeed, it is favoured from SSL to HSA and the fraction of stearic acids transferred increases with temperature in both directions of transfer. Moreover, in the presence of polymer-lipids, the transfer from HSA to SSL is slightly attenuated, especially in the brush regime of the polymer-chains. Instead, the transfer from SSL to HSA is favoured by the polymer-lipids much more in the mushroom than in the brush regime.

  5. Spin-dependent transport properties of oleic acid molecule self-assembled La0.7Sr0.3MnO3 nanoparticles

    International Nuclear Information System (INIS)

    Xi, L.; Du, J.H.; Ma, J.H.; Wang, Z.; Zuo, Y.L.; Xue, D.S.

    2013-01-01

    Highlights: ► Spin-dependent transport property of LSMO/oleic acid nanoparticles is investigated. ► Transport properties and MR measured by Cu/nanoparticle assembly/elargol device. ► Non-linear I–V curve indicates a tunneling type transport properties. ► Tunnel barrier height around 1.3 ± 0.15 eV was obtained by fitting I–V curves. ► LFMR of LSMO/oleic acid molecules value reaches −18% with current of 0.1 μA at 10 K. - Abstract: Spin-dependent transport property through molecules is investigated using a monolayer of oleic acid molecule self-assembled half metallic La 0.7 Sr 0.3 MnO 3 (LSMO) nanoparticles, which was synthesized using a coprecipitation method. Fourier transform infrared spectroscopy was used to confirm that one-monolayer oleic acid molecules chemically bond to the LSMO nanoparticles. The transport properties and magnetoresistance (MR) effect of the oleic acid molecule coated LSMO nanoparticles were measured by a direct current four probes method using a Cu/nanoparticle assembly/elargol electrode sandwich device with various temperatures and bias voltages. The non-linear I–V curve indicates a tunneling type transport properties. The tunnel barrier height around 1.3 ± 0.15 eV was obtained by fitting the I–V curve according to the Simmons equation. The magnetoresistance curves can be divided to high-field MR and low-field MR (LFMR) parts. The former is ascribed to the influence of spin disorder or canting within the LSMO nanoparticle surface and the latter one with strong bias dependence is attributed to the spin-dependent tunneling effect through the insulating surface layer of LSMO and oleic acid molecules. The enhanced LFMR effect for oleic acid coated LSMO with respect to the bare LSMO was attributed to the enhanced tunneling transport and weak spin scattering in oleic acid molecule barrier.

  6. Central transport and distribution of labelled glutamic and aspartic acids to the cochlear nucleus in cats

    International Nuclear Information System (INIS)

    Kane, E.S.

    1979-01-01

    Tritiated L-glutamic acid or L-aspartic acid was injected unilaterally into the cochleas of adult cats, and 4 h-7 days later the localization of label was studied by light-microscopic autoradiography in sections of the brain stem. Consistent differences in labelling after glutamate and after aspartate suggest differences in their uptake, metabolic conversion and/or transport to the cochlear nucleus by cochlear fibers. The morphological differences shown here agree with the distribution of those two amino acids in the cat cochlear nucleus as shown by microchemical analyses. (author)

  7. A novel medium for expression of proteins selectively labeled with {sup 15}N-amino acids in Spodoptera frugiperda (Sf9) insect cells

    Energy Technology Data Exchange (ETDEWEB)

    Brueggert, Michael; Rehm, Till; Shanker, Sreejesh; Georgescu, Julia; Holak, Tad A. [Max Planck Institute for Biochemistry (Germany)], E-mail: holak.biochem@mpg.de

    2003-04-15

    Whereas bacterial expression systems are widely used for production of uniformly or selectively {sup 15}N-labeled proteins the usage of the baculovirus expression system for labeling is limited to very few examples in the literature. Here we present the complete formulations of the two insect media, IML406 and 455, for the high-yield production of selectively {sup 15}N-labeled proteins in insect cells. The quantities of {sup 15}N-amino acids utilized in the production of labeled GST were similar in the case of bacterial and viral expression. For the most studied amino acids essential for insect cells the {sup 15}N-HSQC spectra, recorded with GST labeled in insect cells, showed no cross labeling and provided therefore spectra of better quality compared to NMR spectra of GST expressed in E. coli. Also in the case of amino acids not essential for Sf9 cells we were able to label a defined number of amino acid species. Therefore the selective labeling using the baculovirus expression vector system represents a complement or even an alternative to the bacterial expression system. Based on these findings we can provide a first simple overview of the network of the amino acid metabolism in E. coli and insect cells focused on nitrogen. For some amino acids the expression of labeled proteins in insect cells can replace the cell-free protein expression.

  8. Mandatory food labeling of trans fat acids: qualitative analysis of the public consultation

    Directory of Open Access Journals (Sweden)

    Vanessa Fernandes Davies

    Full Text Available The objective of this paper is to identify the stakeholders and their contributions to the public consultation carried out with regard to the mandatory trans fat acids food labeling proposal in Brazil. Methodology thematic analysis of the documents. Results 25 stakeholders made suggestions regarding the proposed law, and the majority belonged to the food industry sector. The following issues were raised: lack of knowledge among the consumers about trans fat acids; lack of information about trans fat acids in food composition tables and infrastructure to analyse the trans fat content of foods; voluntary trans fat labelling. Conclusions The stakeholders addressed important issues, such as improving nutritional knowledge among the population. However, few stakeholders linked to consumers took part in the public consultation, which might lead to disproportionate influence of the food industry on the development of future food policies.

  9. Characterizing Resting-State Brain Function Using Arterial Spin Labeling

    Science.gov (United States)

    Jann, Kay; Wang, Danny J.J.

    2015-01-01

    Abstract Arterial spin labeling (ASL) is an increasingly established magnetic resonance imaging (MRI) technique that is finding broader applications in studying the healthy and diseased brain. This review addresses the use of ASL to assess brain function in the resting state. Following a brief technical description, we discuss the use of ASL in the following main categories: (1) resting-state functional connectivity (FC) measurement: the use of ASL-based cerebral blood flow (CBF) measurements as an alternative to the blood oxygen level-dependent (BOLD) technique to assess resting-state FC; (2) the link between network CBF and FC measurements: the use of network CBF as a surrogate of the metabolic activity within corresponding networks; and (3) the study of resting-state dynamic CBF-BOLD coupling and cerebral metabolism: the use of dynamic CBF information obtained using ASL to assess dynamic CBF-BOLD coupling and oxidative metabolism in the resting state. In addition, we summarize some future challenges and interesting research directions for ASL, including slice-accelerated (multiband) imaging as well as the effects of motion and other physiological confounds on perfusion-based FC measurement. In summary, this work reviews the state-of-the-art of ASL and establishes it as an increasingly viable MRI technique with high translational value in studying resting-state brain function. PMID:26106930

  10. Synthesis of selectively 13C-labelled benzoic acid for nuclear magnetic resonance spectroscopic measurement of glycine conjugation activity

    International Nuclear Information System (INIS)

    Akira, Kazuki; Hasegawa, Hiroshi; Baba, Shigeo

    1995-01-01

    The synthesis of [4- 13 C]benzoic acid (BA) labelled in a single protonated carbon, for use as a probe to measure glycine conjugation activity by nuclear magnetic resonance (NMR) spectroscopy, has been reported. The labelled compound was prepared by a seven-step synthetic scheme on a relatively small scale using [2- 13 C] acetone as the source of label in overall yield of 16%. The usefulness of [4- 13 C]BA was demonstrated by the NMR spectroscopic monitoring of urinary excretion of [4- 13 C]hippuric acid in the rat administered with the labelled BA. (Author)

  11. Post-PCR detection of nucleic acids using metalloporphyrin labels and time-resolved fluorescence

    International Nuclear Information System (INIS)

    O'Shea, Desmond J.; O'Sullivan, Paul J.; Ponomarev, Gelii V.; Papkovsky, Dmitri B.

    2005-01-01

    Phosphorescent platinum(II)-coproporphyrin label (PtCP) was evaluated in post-PCR detection of nucleic acids by time-resolved fluorescence (TR-F) using three common formats. PtCP-labelled oligonucleotide primers and PtCP-dUTP were incorporated in a PCR to produce labelled amplified target -173 or 305 bp DNA. Alternatively, aminoallyl-dUTP was incorporated in a PCR and the product was subsequently labelled with PtCP. The resulting PCR mixtures containing labelled dsDNA were separated on 1.5% agarose gels and then analysed by ethidium bromide staining and by direct detection of PtCP label on a commercial TR-F plate reader Victor 2 (Perkin Elmer Life Sciences) used in scanning mode. In all cases label incorporation and high yields of amplified DNA were observed. Direct TR-F detection of PtCP-labelled DNA from a gel provided high sensitivity and signal to noise ratio, with limits of detection in the range of 9-22 pg for all three formats. The sensitivity achieved with PtCP label was considerably better than that achieved with ethidium bromide staining (∼1 ng of dsDNA) or with conventional fluorescent label FITC. Neither the FITC label nor ethidium bromide staining interfered with PtCP detection, thus allowing multiplexed detection

  12. Solid state NMR of isotope labelled murine fur: a powerful tool to study atomic level keratin structure and treatment effects

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Wai Ching Veronica; Narkevicius, Aurimas; Chow, Wing Ying; Reid, David G.; Rajan, Rakesh [University of Cambridge, Department of Chemistry (United Kingdom); Brooks, Roger A. [University of Cambridge, Department of Trauma and Orthopaedic Surgery, Addenbrooke’s Hospital (United Kingdom); Green, Maggie [University of Cambridge, Central Biomedical Resources, School of Clinical Medicine (United Kingdom); Duer, Melinda J., E-mail: mjd13@cam.ac.uk [University of Cambridge, Department of Chemistry (United Kingdom)

    2016-10-15

    We have prepared mouse fur extensively {sup 13}C,{sup 15}N-labelled in all amino acid types enabling application of 2D solid state NMR techniques which establish covalent and spatial proximities within, and in favorable cases between, residues. {sup 13}C double quantum–single quantum correlation and proton driven spin diffusion techniques are particularly useful for resolving certain amino acid types. Unlike 1D experiments on isotopically normal material, the 2D methods allow the chemical shifts of entire spin systems of numerous residue types to be determined, particularly those with one or more distinctively shifted atoms such as Gly, Ser, Thr, Tyr, Phe, Val, Leu, Ile and Pro. Also the partial resolution of the amide signals into two signal envelopes comprising of α-helical, and β-sheet/random coil components, enables resolution of otherwise overlapped α-carbon signals into two distinct cross peak families corresponding to these respective secondary structural regions. The increase in resolution conferred by extensive labelling offers new opportunities to study the chemical fate and structural environments of specific atom and amino acid types under the influence of commercial processes, and therapeutic or cosmetic treatments.

  13. Synthesis of 14C-labeled and stable isotope-labeled CGS 16617

    International Nuclear Information System (INIS)

    Chaudhuri, N.K.; Markus, B.; Sung Mingsang

    1988-01-01

    The synthesis of a 14 C-labeled and two stable isotope-labeled analogs of CGS 16617 is described. The synthetic method involved the preparation of tetrahydro-3-bromo-1-benzazepin-2-one, labeled with a 14 C or four deuterium atoms, followed by introduction of two side chains at 1- and 3-positions. The labeled bromobenzazepinones were prepared by Beckmann rearrangement of bromo-oximes of α-tetralones, obtained by cyclization of labeled benzenebutanoic acids. The 14 C-labeled acid was prepared by hydrolysis of the nitrile, prepared by reaction of 3-bromopropylbenzene and K 14 CN. The tetradeutero acid was prepared from ethyl phenylpropynoate by catalytic reduction of the triple bond with deuterium gas, followed by reduction of the deuterated ester with lithium aluminium hydride and conversion of the resulting alcohol into the carboxylic acid. The acetic acid side chain was introduced by N-alkylation with ethyl bromoacetate or ethyl bromoacetate-1, 2- 13 C 2 followed by hydrolysis, and the L-lysine side chain, by reaction with L-(-)-3-amino-ε-caprolactam followed by hydrolysis of the caprolactam ring. (author)

  14. Radioimmunoassay of conjugated cholic acid, chenodeoxycholic acid, and deoxycholic acid from human serum, with use of 125I-labeled ligands

    International Nuclear Information System (INIS)

    Maeentausta, O.; Jaenne, O.

    1979-01-01

    We describe a method for radioimmunoassay of conjugated cholic acid, chenodeoxycholic acid, and deoxycholic acid in serum. In the method, 125 I-labeled bile acid conjugates are used as the tracers along with antibodies raised against individual bile acid-bovine serum albumin conjugates. Antibody-bound and free bile acids were separated by polyethylene glycol precipitation (final concentration, 125 g/L). The lowest measurable amounts of the bile acids, expressed as pmol/tube, were: cholic acid conjugates, 2; chenodeoxycholic acid conjugates, 0.5; and deoxycholic acid conjugates, 2. Analytical recovery of bile acids added to bile acid-free serum ranged from 85 to 110%; intra-assay and inter-assay CVs ranged from 8.3 to 5.3% and from 5.3 to 12.2%, respectively. Concentrations (mean +- SD) of the bile acid conjugates in serum from apparently healthy women and men (in μmol/L) were: cholic acid conjugates, 0.43 +- 0.17 (n=126); chenodeoxycholic acid conjugates, 0.47 +- 0.23 (n=111); and deoxycholic acid conjugates, 0.33 +- 0.11 (n=96). The values for primary bile acids were greatly increased in patients with various hepatobiliary diseases

  15. Synthesis of [14C]-labelled eicosa-5,8,11-triynoic acid and conversion to anti-inflammatory amides

    International Nuclear Information System (INIS)

    Pilgrim, W.R.; Nedoncelle, P.; Shroot, B.; Maignan, J.; Restle, S.

    1991-01-01

    A four step synthesis of [5,6- 14 C]-eicosa-5,8,11-triynoic acid from [ 14 C]-labelled acetylene is described. [ 14 C 2 ]-acetylene was converted to 5-chloro-[1,2- 14 C]-pentyne via reaction of its monolithium salt with 3-bromo-1-chloropropane. The doubly labelled 5-chloropentyne thus obtained was transformed to [5,6- 14 C]-hex-5-ynoic acid which was then coupled with 1-chloro-tetradeca-2,5-diyne to give the title compound. Using 2-(2-aminoethoxy)ethanol and 1-(2-hydroxyethyl)piperazine, amides which had previously been found to be potent inhibitors of the 5-lipoxygenase enzyme, were prepared from [ 14 C-labelled eicosatriynoic acid by way of acylimidazole chemistry. (author)

  16. Synthesis of novel {sup 68}Ga-labeled amino acid derivatives for positron emission tomography of cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Shetty, Dinesh [Department of Nuclear Medicine, Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Department of Radiation Applied Life Science, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Jeong, Jae Min, E-mail: jmjng@snu.ac.k [Department of Nuclear Medicine, Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Department of Radiation Applied Life Science, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Ju, Chang Hwan [Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Department of Life and Nanopharmaceutical Sciences, Graduate School, Kyung Hee University, Seoul (Korea, Republic of); Lee, Yun-Sang [Department of Nuclear Medicine, Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Department of Radiation Applied Life Science, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Jeong, Seo Young [Department of Life and Nanopharmaceutical Sciences, Graduate School, Kyung Hee University, Seoul (Korea, Republic of); Choi, Jae Yeon; Yang, Bo Yeun [Department of Nuclear Medicine, Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Department of Radiation Applied Life Science, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of)

    2010-11-15

    Objectives: We developed amino acid derivatives of 1,4,7,10-tetraazacyclododecane-1,7-diacetic acid (DO2A) and 1,4,7,10-tetraazacyclododecane-1,4,7,-triacetic acid (DO3A) that can be labeled with {sup 68}Ga, and we investigated their basic biological properties. Materials and methods: Alanine derivatives of DO2A and DO3A were synthesized by regiospecific nucleophilic attack of DO2tBu and DO3tBu on the {beta}-position of Boc-L-serine-{beta}-lactone, followed by acid hydrolysis. Also, homoalanine derivatives were synthesized by reacting with the protected bromo derivative of homoalanine, which was synthesized from N-Cbz-L-homoserine lactone. Further catalytic reduction and acid cleavage of protected groups resulted in the required products. All derivatives were labeled with {sup 68}Ga. Cell uptake assays were carried out in Hep3B (human hepatoma) and U87MG (human glioma) cell lines at 37{sup o}C. Positron emission tomography (PET) imaging studies were performed using balb/c mice xenografted with CT-26 (mouse colon cancer). Results: All compounds were labeled with >97% efficiency. According to in vitro studies, the labeled amino acid derivatives showed significantly greater uptakes than the control ({sup 68}Ga 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) in cancer cells. Small animal PET images for labeled compounds showed high tumor uptake, as well as kidney and bladder uptakes, at 30 min postinjection. {sup 68}Ga-DO3A-homoalanine showed the highest standardized uptake value ratio (3.9{+-}0.3), followed by {sup 68}Ga-DO2A-alanine (3.1{+-}0.2), {sup 68}Ga-DO3A-alanine (2.8{+-}0.2) and {sup 68}Ga-DO2A-homoalanine (2.3{+-}0.2). Conclusion: These derivatives were found to have high labeling efficiencies, high stabilities, high tumor cell uptakes, high tumor/nontumor xenograft uptakes and low nonspecific uptake in normal organs, except for the kidneys. However, the uptake mechanism of these derivatives remains unclear, and uptake via specific amino acid

  17. Labelling by deuteration and nitroxide radicals of mono-, oligo- and polysaccharides (cellulose and amylose)

    Energy Technology Data Exchange (ETDEWEB)

    Odier, L

    1975-01-01

    The application of NMR and deuteration labelling to the investigation of polysaccharides has led to considerable progress in recent years in the knowledge of these compounds. Although far more recent, the introduction of spin labelling techniques in the investigation of polymers, has given rise to interesting EPR studies of synthetic and natural macromolecules, but nothing appears to have been accomplished in the area of spin labelling of polysaccharides. This work was aimed at applying these two techniques to the study of glucose derivatives and of some of its oligomers (low molecular weight polymers): cellobiose, maltose and cyclodextrins; and its polymers: cellulose and amylose. Irrespective of the technique employed, the complexity of the polymers and problems connected with handling them always require the same procedure: an initial study of a model compound generally prepared from the monomer or an oligomer (dimer), followed by the oligomers, and finally the polymer. Part 1 is devoted to the deuteration labelling of mono- and oligosaccharides. Part 2 concerns spin labelling of cellulose acetate. In part 3, an attempt is made to apply the spin labelling technique to the determination of conformations of two disaccharides of different glycosidic configurations: cellobiose and maltose. Part 4 is devoted to spin and deuteration labelling of ..cap alpha.. and ..beta.. cyclodextrins.

  18. Tritium labeling of amino acids and peptides with liquid and solid tritium

    International Nuclear Information System (INIS)

    Peng, C.T.; Hua, R.L.; Souers, P.C.; Coronado, P.R.

    1988-01-01

    Amino acids and peptides were labeled with liquid and solid tritium at 21 K and 9 K. At these low temperatures radiation degradation is minimal, and tritium incorporation increases with tritium concentration and exposure time. Ring saturation in L-phenyl-alanine does not occur. Peptide linkage in oligopeptides is stable toward tritium. Deiodination in 3-iodotyrosine and 3,5-diiodotyrosine occurs readily and proceeds in steps by losing one iodine atom at a time. Nickel and noble metal supported catalysts when used as supports for dispersion of the substrate promote tritium labeling at 21 K. Our study shows that both liquid and solid tritium are potentially useful agents for labeling peptides and proteins. 11 refs., 1 fig., 3 tabs

  19. Tritium labeling of amino acids and peptides with liquid and solid tritium

    International Nuclear Information System (INIS)

    Souers, P.C.; Coronado, P.R.; Peng, C.T.; Hua, R.L.

    1988-01-01

    Amino acids and peptides were labeled with liquid and solid tritium at 21/degree/K and 9/degree/K. At these low temperatures radiation degradation is minimal, and tritium incorporation increases with tritium concentration and exposure time. Ring saturation in L-phenylalanine does not occur. Peptide linkage in oligopeptides is stable toward tritium. Deiodination in 3-iodotyrosine and 3,5-diiodotyrosine occurs readily and proceeds in steps by losing one iodine atom at a time. Nickel and noble metal supported catalysts when used as supports for dispersion of the substrate promote tritium labeling at 21 K. Our study shows that both liquid and solid tritiums are potentially useful agents for labeling peptides and proteins

  20. Renal blood flow using arterial spin labelling MRI and calculated filtration fraction in healthy adult kidney donors Pre-nephrectomy and post-nephrectomy.

    Science.gov (United States)

    Cutajar, Marica; Hilton, Rachel; Olsburgh, Jonathon; Marks, Stephen D; Thomas, David L; Banks, Tina; Clark, Christopher A; Gordon, Isky

    2015-08-01

    Renal plasma flow (RPF) (derived from renal blood flow, RBF) and glomerular filtration rate (GFR) allow the determination of the filtration fraction (FF), which may have a role as a non-invasive renal biomarker. This is a hypothesis-generating pilot study assessing the effect of nephrectomy on renal function in healthy kidney donors. Eight living kidney donors underwent arterial spin labelling (ASL) magnetic resonance imaging (MRI) and GFR measurement prior to and 1 year after nephrectomy. Chromium-51 labelled ethylenediamine tetraacetic acid ((51)Cr-EDTA) with multi-blood sampling was undertaken and GFR calculated. The RBF and GFR obtained were used to calculate FF. All donors showed an increase in single kidney GFR of 24 - 75 %, and all but two showed an increase in FF (-7 to +52 %) after nephrectomy. The increase in RBF, and hence RPF, post-nephrectomy was not as great as the increase in GFR in seven out of eight donors. As with any pilot study, the small number of donors and their relatively narrow age range are potential limiting factors. The ability to measure RBF, and hence RPF, non-invasively, coupled with GFR measurement, allows calculation of FF, a biomarker that might provide a sensitive indicator of loss of renal reserve in potential donors. • Non-invasive MRI measured renal blood flow and calculated renal plasma flow. • Effect of nephrectomy on blood flow and filtration in donors is presented. • Calculated filtration fraction may be a useful new kidney biomarker.

  1. Preparation of carbon-11 labelled phenylalanine and phenylglycine by a new amino acid synthesis

    International Nuclear Information System (INIS)

    Vaalburg, W.; Beerling-van der Molen, H.D.; Reiffers, S; Rijskamp, A.; Woldring, M.G.; Wynberg, H.

    1976-01-01

    Of the cyclotron-produced short-lived isotopes carbon-11 (tsub(1/2) = 20.4 min;β + ) is one of the most promising as label for radiopharmaceuticals. To prepare 11 C-labelled amino acids for evaluation as pancreas scanning agents a new rapid amino acid synthesis was developed. The method is based on the carboxylation of α-lithioisocyanides with 11 CO 2 , followed by hydrolysis of the intermediate reaction product to the desired amino acid. By this method DL-α-phenylalanine-1- 11 C and DL-α-phenylglycine-1- 11 C were prepared. The precursor 11 CO 2 was produced via the 14 N(p,α) 11 C reaction by bombardment of a flow of nitrogen gas mixed with 0.1% 0 2 with 20 MeV protons. The target system is described. (author)

  2. Arterial spin-labeling assessment of normalized vascular intratumoral signal intensity as a predictor of histologic grade of astrocytic neoplasms.

    Science.gov (United States)

    Furtner, J; Schöpf, V; Schewzow, K; Kasprian, G; Weber, M; Woitek, R; Asenbaum, U; Preusser, M; Marosi, C; Hainfellner, J A; Widhalm, G; Wolfsberger, S; Prayer, D

    2014-03-01

    Pulsed arterial spin-labeling is a noninvasive MR imaging perfusion method performed with the use of water in the arterial blood as an endogenous contrast agent. The purpose of this study was to determine the inversion time with the largest difference in normalized intratumoral signal intensity between high-grade and low-grade astrocytomas. Thirty-three patients with gliomas, histologically classified as low-grade (n = 7) or high-grade astrocytomas (n = 26) according to the World Health Organization brain tumor classification, were included. A 3T MR scanner was used to perform pulsed arterial spin-labeling measurements at 8 different inversion times (370 ms, 614 ms, 864 ms, 1114 ms, 1364 ms, 1614 ms, 1864 ms, and 2114 ms). Normalized intratumoral signal intensity was calculated, which was defined by the signal intensity ratio of the tumor and the contralateral normal brain tissue for all fixed inversion times. A 3-way mixed ANOVA was used to reveal potential differences in the normalized vascular intratumoral signal intensity between high-grade and low-grade astrocytomas. The difference in normalized vascular intratumoral signal intensity between high-grade and low-grade astrocytomas obtained the most statistically significant results at 370 ms (P = .003, other P values ranged from .012-.955). The inversion time by which to differentiate high-grade and low-grade astrocytomas by use of normalized vascular intratumoral signal intensity was 370 ms in our study. The normalized vascular intratumoral signal intensity values at this inversion time mainly reflect the labeled intra-arterial blood bolus and therefore could be referred to as normalized vascular intratumoral signal intensity. Our data indicate that the use of normalized vascular intratumoral signal intensity values allows differentiation between low-grade and high-grade astrocytomas and thus may serve as a new, noninvasive marker for astrocytoma grading.

  3. Behavior of 15N-labelled amino acids in germinated corn

    International Nuclear Information System (INIS)

    Samukawa, Kisaburo; Yamaguchi, Masuro

    1979-01-01

    By investigating the rise and fall of 15 N-labelled amino acids in germinated corns, the behavior of amino radicals in free amino acids, the influence of the hydrolysis products of stored proteins on free amino acids and the change from heterotrophy to autotrophy of seeds were clarified. The amount of amino acid production depending on external nitrogen was very small in the early period of germination. 15 N incorporation into proline was not observed in the early period of germination, which suggested that the proline may be nitrogen-storing source. Most of the amino-state nitrogen of asparagine accumulated at the time of germination was internal nitrogen, and this fact suggested that aspartic acid serve as the acceptor of ammonia produced in the early stage of germination. 15 N content increased significantly on 9 th day after germination, and decreased on 12 th day. These facts prove that there are always active decomposition and production of protein in plant body. (Kobatake, H.)

  4. Nuclear magnetic resonance and LC/MS characterization of native and new mass-labeled fluorinated telomer alcohols, acids and unsaturated acids

    Energy Technology Data Exchange (ETDEWEB)

    Arsenault, G.; Chittim, B.; McAlees, A.; Yeo, B. [Wellington Laboratories Inc., Guelph, ON (Canada); Ellis, D.; Mabury, S.; Stock, N. [Toronto Univ., ON (Canada); Halldorson, T.; Tomy, G. [Dept. of Fisheries and Oceans, Winnipeg, MB (Canada); McCrindle, R. [Guelph Univ., ON (Canada)

    2004-09-15

    A variety of fluorinated compounds are used in a multitude of consumer products because of their ability to repel water and oil, resistance to heat, and chemical inertness. Recently, scientists and regulators have begun raising concerns about the potential health and environmental impact of perfluorinated compounds. Exposure to perfluoroalkyl acids, such as Perfluorooctanoic acid (PFOA), has been identified as a potential human health concern. A study has shown that telomer alcohols such as 2-perfluorooctylethanol can be metabolized by living organisms or biodegrade under environmental conditions to sequentially give the saturated fluorinated telomer acid (2- perfluorooctylethanoic acid), then the unsaturated telomer acid (2H-Perfluorooct-2-enoic acid), and eventually PFOA. Additional experimental work is necessary to determine the extent, if any, to which telomer product degradation may be a source of PFOA. The analysis for fluorinated compounds in environmental samples is performed, primarily, using LC/MS techniques. These analyses have been hindered by the lack of any commercially available mass-labeled fluorinated compounds for use as surrogates and thus may be restricting the amount of research conducted in this area. We have now synthesized the mass-labeled perfluoroalkyl telomer alcohols and the corresponding acids and unsaturated acids. We report in this study their 1H-, 2H-, 19F- and 13C-NMR characterizations along with GC/MS and LC/MS data and evaluation of their use as surrogate standards.

  5. Specific Labeling of Zinc Finger Proteins using Non-canonical Amino Acids and Copper-free Click Chemistry

    Science.gov (United States)

    Kim, Younghoon; Kim, Sung Hoon; Ferracane, Dean; Katzenellenbogen, John A.

    2012-01-01

    Zinc finger proteins (ZFPs) play a key role in transcriptional regulation and serve as invaluable tools for gene modification and genetic engineering. Development of efficient strategies for labeling metalloproteins such as ZFPs is essential for understanding and controlling biological processes. In this work, we engineered ZFPs containing cysteine-histidine (Cys2-His2) motifs by metabolic incorporation of the unnatural amino acid azidohomoalanine (AHA), followed by specific protein labeling via click chemistry. We show that cyclooctyne promoted [3 + 2] dipolar cycloaddition with azides, known as copper-free click chemistry, provides rapid and specific labeling of ZFPs at high yields as determined by mass spectrometry analysis. We observe that the DNA-binding activity of ZFPs labeled by conventional copper-mediated click chemistry was completely abolished, whereas ZFPs labeled by copper-free click chemistry retain their sequence-specific DNA-binding activity under native conditions, as determined by electrophoretic mobility shift assays, protein microarrays and kinetic binding assays based on Förster resonance energy transfer (FRET). Our work provides a general framework to label metalloproteins such as ZFPs by metabolic incorporation of unnatural amino acids followed by copper-free click chemistry. PMID:22871171

  6. Tritium ( 3 H) Retention In Mice: Administered As HTO, DTO or as 3 H-Labeled Amino-Acids.

    Science.gov (United States)

    Priest, Nicholas D; Blimkie, Melinda S J; Wyatt, Heather; Bugden, Michelle; Bannister, Laura A; Gueguen, Yann; Jourdain, Jean-Rene; Klokov, Dmitry

    2017-05-01

    The objective of this study was to compare the biokinetics of injected H-labeled light (HTO) and heavy (DTO) water in CBA/CaJ mice and to compare the organ distribution and/or body content of H administered by chronic ingestion for 1 mo to C57Bl/6J mice, as either H-labeled water or H-labeled amino acids (glycine, alanine and proline). HTO and DTO were administered to CBA/CaJ mice by single intraperitoneal injection and body retention was determined for up to 384 h post-injection. Tritium-labeled water or H-labeled amino acids were given to C57Bl/6J mice ad libitum for 30 d in drinking water. Body content and organ distribution of H during the period of administration and subsequent to administration was determined by liquid scintillation counting. No differences were found between the biokinetics of HTO and DTO, indicating that data generated using HTO can be used to help assess the consequences of H releases from heavy water reactors. The results for H-water showed that the concentration of radionuclide in the mice reached a peak after about 10 d and dropped rapidly after the cessation of H administration. The maximum concentration reached was only 50% of that in the water consumed, indicating that mice receive a significant fraction of their water from respiration. Contrary to the findings of others, the pattern of H retention following the administration of a cocktail of the labeled amino acids was very little different from that found for the water. This is consistent with the suggestion that most of the ingested amino acids were rapidly metabolized, releasing water and carbon dioxide.

  7. Synthesis of ( sup 14 C)-labelled eicosa-5,8,11-triynoic acid and conversion to anti-inflammatory amides

    Energy Technology Data Exchange (ETDEWEB)

    Pilgrim, W R; Nedoncelle, P; Shroot, B [Centre International de Recherches Dermatologiques Galderma, Valbonne (France); Maignan, J; Restle, S [L' Oreal, Lab. de Recherches Fondamentales, Aulnay sous Bois, (France)

    1991-07-01

    A four step synthesis of (5,6-{sup 14}C)-eicosa-5,8,11-triynoic acid from ({sup 14}C)-labelled acetylene is described. ({sup 14}C{sub 2})-acetylene was converted to 5-chloro-(1,2-{sup 14}C)-pentyne via reaction of its monolithium salt with 3-bromo-1-chloropropane. The doubly labelled 5-chloropentyne thus obtained was transformed to (5,6-{sup 14}C)-hex-5-ynoic acid which was then coupled with 1-chloro-tetradeca-2,5-diyne to give the title compound. Using 2-(2-aminoethoxy)ethanol and 1-(2-hydroxyethyl)piperazine, amides which had previously been found to be potent inhibitors of the 5-lipoxygenase enzyme, were prepared from ({sup 14}C)-labelled eicosatriynoic acid by way of acylimidazole chemistry. (author).

  8. Recycling of an amino acid label with prolonged isotope infusion: Implications for kinetic studies

    International Nuclear Information System (INIS)

    Schwenk, W.F.; Tsalikian, E.; Beaufrere, B.; Haymond, M.W.

    1985-01-01

    To investigate whether recycling of a labeled amino acid would occur after 24 h of infusion, two groups of normal volunteers were infused with [ 3 H]leucine and alpha-[ 14 C]-ketoisocaproate for 4 h and [ 2 H 3 ]leucine for either 4 or 24 h (groups I and II, respectively). Entry of [ 2 H 3 ]leucine at steady state into the plasma space was indistinguishable from its infusion rate for group I but 30% higher (P less than 0.001) than this rate for group II, demonstrating significant recycling of label. After discontinuation of the infusions, isotope disappearance from the plasma space was followed for 2 h. The 3 H and 14 C decay data for both groups suggest that plasma leucine and alpha- ketoisocaproate are derived from a single intracellular pool in the postabsorptive state. In group I, the 3 H and 2 H labels decayed identically; whereas, in group II, the decay of [ 2 H 3 ]-leucine and alpha- [ 2 H 3 ]ketoisocaproate was slower (P less than 0.01) than the decay of [ 3 H]leucine and alpha-[ 3 H]ketoisocaproate, confirming re-entry of label after a 24-h infusion. Therefore kinetic values calculated from models assuming no recycling of labeled amino acids are most likely not quantitative and must be interpreted with care when flux does not change or decreases

  9. Site-Specific Protein Labeling Utilizing Lipoic Acid Ligase (LplA) and Bioorthogonal Inverse Electron Demand Diels-Alder Reaction.

    Science.gov (United States)

    Baalmann, Mathis; Best, Marcel; Wombacher, Richard

    2018-01-01

    Here, we describe a two-step protocol for selective protein labeling based on enzyme-mediated peptide labeling utilizing lipoic acid ligase (LplA) and bioorthogonal chemistry. The method can be applied to purified proteins, protein in cell lysates, as well as living cells. In a first step a W37V mutant of the lipoic acid ligase (LplA W37V ) from Escherichia coli is utilized to ligate a synthetic chemical handle site-specifically to a lysine residue in a 13 amino acid peptide motif-a short sequence that can be genetically expressed as a fusion with any protein of interest. In a second step, a molecular probe can be attached to the chemical handle in a bioorthogonal Diels-Alder reaction with inverse electron demand (DA inv ). This method is a complementary approach to protein labeling using genetic code expansion and circumvents larger protein tags while maintaining label specificity, providing experimental flexibility and straightforwardness.

  10. QUANTITATIVE CHANGES IN REGIONAL CEREBRAL BLOOD FLOW INDUCED BY COLD, HEAT AND ISCHEMIC PAIN: A CONTINUOUS ARTERIAL SPIN LABELING STUDY

    Science.gov (United States)

    Frölich, Michael A.; Deshpande, Hrishikesh; Ness, Timothy; Deutsch, Georg

    2012-01-01

    Background The development of arterial spin labeling methods, has allowed measuring regional cerebral blood flow (rCBF) quantitatively and to show the pattern of cerebral activity associated with any state such as a sustained pain state or changes due to a neurotropic drug. Methods We studied the differential effects of three pain conditions in ten healthy subjects on a 3T scanner during resting baseline, heat, cold and ischemic pain using continuous arterial spin labeling. Results Cold pain showed the greatest absolute rCBF increases in left anterior cingulate cortex, left amygdala, left angular gyrus, and Brodmann Area 6, and a significant rCBF decrease in the cerebellum. Changes in rCBF were characteristic of the type of pain condition: cold and heat pain showed increases, while the ischemic condition showed a reduction in mean absolute gray matter flow compared to rest. An association of subjects’ pain tolerance and cerebral blood flow was noted. Conclusions The observation that quantitative rCBF changes are characteristic of the pain task employed and that there is a consistent rCBF change in Brodman area 6, an area responsible for the integration of a motor response to pain, should provide extremely useful information in the quest to develop an imaging biomarker of pain. Conceivably, response in BA6 may serve as an objective measure of analgesic efficacy. PMID:22913924

  11. Quantitative changes in regional cerebral blood flow induced by cold, heat and ischemic pain: a continuous arterial spin labeling study.

    Science.gov (United States)

    Frölich, Michael A; Deshpande, Hrishikesh; Ness, Timothy; Deutsch, Georg

    2012-10-01

    The development of arterial spin labeling methods has allowed measuring regional cerebral blood flow (rCBF) quantitatively and to show the pattern of cerebral activity associated with any state such as a sustained pain state or changes due to a neurotropic drug. The authors studied the differential effects of three pain conditions in 10 healthy subjects on a 3 Tesla scanner during resting baseline, heat, cold, and ischemic pain using continuous arterial spin labeling. Cold pain showed the greatest absolute rCBF increases in left anterior cingulate cortex, left amygdala, left angular gyrus, and Brodmann area 6, and a significant rCBF decrease in the cerebellum. Changes in rCBF were characteristic of the type of pain condition: cold and heat pain showed increases, whereas the ischemic condition showed a reduction in mean absolute gray matter flow compared with rest. An association of subjects' pain tolerance and cerebral blood flow was noted. The observation that quantitative rCBF changes are characteristic of the pain task used and that there is a consistent rCBF change in Brodman area 6, an area responsible for the integration of a motor response to pain, should provide extremely useful information in the quest to develop an imaging biomarker of pain. Conceivably, response in BA6 may serve as an objective measure of analgesic efficacy.

  12. Mononitroxides and proximate dinitroxides derived by oxidation of 2,2,4,4,5,5-hexasubstituted imidazolidines. A new series of nitroxide and dinitroxide spin labels

    International Nuclear Information System (INIS)

    Keana, J.F.W.; Norton, R.S.; Morello, M.; Van Engen, D.; Clardy, J.

    1978-01-01

    The synthesis and some properties of two members of a new series of rigid dinitroxides in which the nitroxide groups are separated from each other by only one carbon atom are reported. The synthesis of reverse intermediate imidazolidine mononitroxides which may have potential as new spin labels is also reported

  13. Accelerated territorial arterial spin labeling based on shared rotating control acquisition: an observer study for validation

    International Nuclear Information System (INIS)

    Kamano, Hironori; Yoshiura, Takashi; Hiwatashi, Akio; Yamashita, Koji; Takayama, Yukihisa; Nagao, Eiki; Sagiyama, Koji; Honda, Hiroshi; Zimine, Ivan

    2012-01-01

    Shared rotating control acquisition can shorten the imaging time of territorial arterial spin labeling (tASL) by 33% compared with the normal control acquisition scheme but potentially results in an inaccurate estimate of vascular territories due to imperfect magnetization transfer compensation. Our purpose was to validate the accuracy of the shared rotating control acquisition method in evaluation of vascular territories. Twenty-four patients underwent tASL at a 3.0-T MRI with the conventional normal control acquisition method. Composite vascular territory maps, in which the blood flows from the right and left internal carotid arteries and the posterior circulation were encoded in red-green-blue, were generated as a normal averaged control-label scheme and as a simulated shared rotating control scheme. Two observers independently reported the most dominant territorial flow in 26 brain regions corresponding to the arterial segments at three post-labeling time points. Inter-reader and inter-method agreements were analyzed using κ statistics. Overall inter-reader agreements were excellent for both the normal control and the shared rotating control methods (κ = 0.98, respectively). Overall inter-method agreement was also excellent (κ = 0.98), although relatively low agreement was noted in the bilateral posterior cerebral artery territories (κ = 0.79 to 0.93). Our results suggested that tASL using shared rotating control acquisition can provide information on the vascular territories comparable to that obtained using the normal control acquisition while substantially shortening the imaging time. (orig.)

  14. Preparation of carbon-11 labelled phenylalanine and phenylglycine by a new amino acid synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Vaalburg, W; Beerling-van der Molen, H D; Reiffers, S; Rijskamp, A; Woldring, M G; Wynberg, H [Academic Hospital, Groningen (Netherlands). Central Isotope Lab.

    1976-03-01

    Of the cyclotron-produced short-lived isotopes carbon-11 (tsub(1/2) = 20.4 min;..beta../sup +/) is one of the most promising as label for radiopharmaceuticals. To prepare /sup 11/C-labelled amino acids for evaluation as pancreas scanning agents a new rapid amino acid synthesis was developed. The method is based on the carboxylation of ..cap alpha..-lithioisocyanides with /sup 11/CO/sub 2/, followed by hydrolysis of the intermediate reaction product to the desired amino acid. By this method DL-..cap alpha..-phenylalanine-1-/sup 11/C and DL-..cap alpha..-phenylglycine-1-/sup 11/C were prepared. The precursor /sup 11/CO/sub 2/ was produced via the /sup 14/N(p,..cap alpha..)/sup 11/C reaction by bombardment of a flow of nitrogen gas mixed with 0.1% 0/sub 2/ with 20 MeV protons. The target system is described.

  15. Intersubunit distances in full-length, dimeric, bacterial phytochrome Agp1, as measured by pulsed electron-electron double resonance (PELDOR) between different spin label positions, remain unchanged upon photoconversion.

    Science.gov (United States)

    Kacprzak, Sylwia; Njimona, Ibrahim; Renz, Anja; Feng, Juan; Reijerse, Edward; Lubitz, Wolfgang; Krauss, Norbert; Scheerer, Patrick; Nagano, Soshichiro; Lamparter, Tilman; Weber, Stefan

    2017-05-05

    Bacterial phytochromes are dimeric light-regulated histidine kinases that convert red light into signaling events. Light absorption by the N-terminal photosensory core module (PCM) causes the proteins to switch between two spectrally distinct forms, Pr and Pfr, thus resulting in a conformational change that modulates the C-terminal histidine kinase region. To provide further insights into structural details of photoactivation, we investigated the full-length Agp1 bacteriophytochrome from the soil bacterium Agrobacterium fabrum using a combined spectroscopic and modeling approach. We generated seven mutants suitable for spin labeling to enable application of pulsed EPR techniques. The distances between attached spin labels were measured using pulsed electron-electron double resonance spectroscopy to probe the arrangement of the subunits within the dimer. We found very good agreement of experimental and calculated distances for the histidine-kinase region when both subunits are in a parallel orientation. However, experimental distance distributions surprisingly showed only limited agreement with either parallel- or antiparallel-arranged dimer structures when spin labels were placed into the PCM region. This observation indicates that the arrangements of the PCM subunits in the full-length protein dimer in solution differ significantly from that in the PCM crystals. The pulsed electron-electron double resonance data presented here revealed either no or only minor changes of distance distributions upon Pr-to-Pfr photoconversion. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. Incorporation of deuterium-labeled trans- and cis-13-octadecenoic acids in human plasma lipids

    International Nuclear Information System (INIS)

    Emken, E.A.; Adlof, R.O.; Rohwedder, W.K.; Gulley, R.M.

    1983-01-01

    The absorption and distribution of deuterated trans- and cis-13-octadecenoic acid (13t-18:1 and 13c-18:1) in plasma lipids were compared to deuterated cis-9-octadecenoic acid (9c-18:1) in two young adult male subjects. A mixture of triglycerides was fed in a multiple-labeled experiment where each triglyceride contained a fatty acid labeled with a different number of deuterium atoms. Analysis of human plasma lipids by mass spectroscopy allowed the distribution of the two 13-octadecenoic acid isomers to be directly compared to cis-9-octadecenoic acid. Plasma lipids selectively excluded both the 13t-18:1 and 13c-18:1 isomers relative to 9c-18:1 in all neutral and phospholipid fractions. Discrimination against incorporation of the 13t-18:1 isomer into plasma cholesteryl ester and 2-acyl phosphatidylcholine was nearly absolute. The 1-acyl phosphatidylcholine fraction exhibited a large positive selectivity for the 13t-18:1 isomer. Differences in the relative distribution of the trans and cis 13-18:1 isomers vs. 9c-18:1 in the various lipoprotein lipid classes were found. Analysis of the chylomicron triglyceride component of the plasma lipids indicated all three fatty acids were equally well absorbed

  17. End-labeling of peptide nucleic acid with osmium complex. Voltammetry at carbon and mercury electrodes

    Czech Academy of Sciences Publication Activity Database

    Paleček, Emil; Trefulka, Mojmír; Fojta, Miroslav

    2009-01-01

    Roč. 11, č. 2 (2009), s. 359-362 ISSN 1388-2481 R&D Projects: GA AV ČR(CZ) KAN400310651; GA MŠk(CZ) LC06035 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : peptide nucleic acid end-labeling * osmium tetroxide complexes * electroactive labels Subject RIV: BO - Biophysics Impact factor: 4.243, year: 2009

  18. Arterial Spin Labeling (ASL) fMRI: advantages, theoretical constrains, and experimental challenges in neurosciences.

    Science.gov (United States)

    Borogovac, Ajna; Asllani, Iris

    2012-01-01

    Cerebral blood flow (CBF) is a well-established correlate of brain function and therefore an essential parameter for studying the brain at both normal and diseased states. Arterial spin labeling (ASL) is a noninvasive fMRI technique that uses arterial water as an endogenous tracer to measure CBF. ASL provides reliable absolute quantification of CBF with higher spatial and temporal resolution than other techniques. And yet, the routine application of ASL has been somewhat limited. In this review, we start by highlighting theoretical complexities and technical challenges of ASL fMRI for basic and clinical research. While underscoring the main advantages of ASL versus other techniques such as BOLD, we also expound on inherent challenges and confounds in ASL perfusion imaging. In closing, we expound on several exciting developments in the field that we believe will make ASL reach its full potential in neuroscience research.

  19. Bacterial production of site specific {sup 13}C labeled phenylalanine and methodology for high level incorporation into bacterially expressed recombinant proteins

    Energy Technology Data Exchange (ETDEWEB)

    Ramaraju, Bhargavi; McFeeters, Hana; Vogler, Bernhard; McFeeters, Robert L., E-mail: robert.mcfeeters@uah.edu [University of Alabama in Huntsville, Department of Chemistry (United States)

    2017-01-15

    Nuclear magnetic resonance spectroscopy studies of ever larger systems have benefited from many different forms of isotope labeling, in particular, site specific isotopic labeling. Site specific {sup 13}C labeling of methyl groups has become an established means of probing systems not amenable to traditional methodology. However useful, methyl reporter sites can be limited in number and/or location. Therefore, new complementary site specific isotope labeling strategies are valuable. Aromatic amino acids make excellent probes since they are often found at important interaction interfaces and play significant structural roles. Aromatic side chains have many of the same advantages as methyl containing amino acids including distinct {sup 13}C chemical shifts and multiple magnetically equivalent {sup 1}H positions. Herein we report economical bacterial production and one-step purification of phenylalanine with {sup 13}C incorporation at the Cα, Cγ and Cε positions, resulting in two isolated {sup 1}H-{sup 13}C spin systems. We also present methodology to maximize incorporation of phenylalanine into recombinantly overexpressed proteins in bacteria and demonstrate compatibility with ILV-methyl labeling. Inexpensive, site specific isotope labeled phenylalanine adds another dimension to biomolecular NMR, opening new avenues of study.

  20. 78 FR 66826 - Prior Label Approval System: Generic Label Approval

    Science.gov (United States)

    2013-11-07

    ... raising of animals, such as ``no antibiotics administered'' or ``vegetarian fed''; (4) instructional or... Standards and Labeling Policy Book includes animal production claims; omega fatty acid guidance; allergen... inclusion of Country of Origin Labeling on all labels; the production and sale of labels by USDA; developing...

  1. Labelling study of galacturonic acid with Tc-99m and investigation of the biokinetic behaviour in experimental animals

    International Nuclear Information System (INIS)

    1988-01-01

    The main criterion in the selection of a proper ligand to be labelled with Technetium is to match the requirement of a radiopharmaceutical of good biological specificity, where the target organ-to-background ratio is considerably high. Perliminary study on experimental animals has shown, that galacturonic acid is among those ligands of high renal specificity after complexing with Tc-99. In this communication we describe for the first time the labelling of galacturonic acid with Tc-99, using stannous chloride as a reducing agent for pertechnetate. The radioanalytical results assessed by gelchromatography column scanning (GCS) method, reveal that, the labelling efficiency of (Tc)99-galacturonate complex is promoted by raising the pH of the reaction mixture to a value higher than 7 using tris (hydroxymethyl) aminomethane buffer. The optimal amounts of the reactants to obtain a high labelled and stable complex with high kidney uptake, were found to be not less than 50 mg galacturonic acid and not more than 200 Mg SnCl2.H2O in the preparation

  2. 123I and131I labelled p-iodophenylpentadecanoic acid (p-IPPA): simplified preparation. Biodistribution in mice, rabbits and patients

    International Nuclear Information System (INIS)

    Angelberger, P.; Wagner-Loeffler, M.; Hruby, R.; Dudczak, R.; Schmoliner, R.; Kletter, K.; Frischauf, H.

    1981-01-01

    In an attempt to avoid the second injection of radioiodide as an internal standard for catabolically released iodide, Machulla et al proposed 15-phenyl-penta-decanoic acid (PPA), labelled at the phenyl ring, for myocardial imaging and metabolic studies. PPA is catabolized via β-oxidation to benzoic acid which is known to be rapidly excreted as hippuric acid. After labelling, three sequential HPLC separations were recommended to purify the labelled p-Isomer (p-IPPA). In this process three intermediate evaporation steps have also to be performed. Thus it seems important to look for improved purification procedures which may possibly reduce the preparation time. The present report compares different purification procedures and relates them to the biodistribution of the final product in mice and rabbits. (Auth.)

  3. Preparation of folic acid specifically labeled with deuterium at the 3',5'-positions

    International Nuclear Information System (INIS)

    Gregory, J.F. III; Toth, J.P.

    1988-01-01

    A method was devised for the synthesis of 3', 5'-[ 2 H 2 ]folic acid (d 2 -folic acid) for use in studies of folate metabolism in human beings. Labeling was accomplished by catalytic dehalogenation of 3', 5'-dibromofolate with deuterium gas and palladium/carbon catalyst. d 2 -Folic acid was separated from reduced forms and residual 3'-monobromofolate by chromatography on DEAE-Sephadex. Analysis by proton NMR and mass spectrometry indicated 70-75% deuteration of the 3',5'-positions and lack of deuteration at other carbons. (author)

  4. Membrane docking geometry of GRP1 PH domain bound to a target lipid bilayer: an EPR site-directed spin-labeling and relaxation study.

    Directory of Open Access Journals (Sweden)

    Huai-Chun Chen

    Full Text Available The second messenger lipid PIP(3 (phosphatidylinositol-3,4,5-trisphosphate is generated by the lipid kinase PI3K (phosphoinositide-3-kinase in the inner leaflet of the plasma membrane, where it regulates a broad array of cell processes by recruiting multiple signaling proteins containing PIP(3-specific pleckstrin homology (PH domains to the membrane surface. Despite the broad importance of PIP(3-specific PH domains, the membrane docking geometry of a PH domain bound to its target PIP(3 lipid on a bilayer surface has not yet been experimentally determined. The present study employs EPR site-directed spin labeling and relaxation methods to elucidate the membrane docking geometry of GRP1 PH domain bound to bilayer-embedded PIP(3. The model target bilayer contains the neutral background lipid PC and both essential targeting lipids: (i PIP(3 target lipid that provides specificity and affinity, and (ii PS facilitator lipid that enhances the PIP(3 on-rate via an electrostatic search mechanism. The EPR approach measures membrane depth parameters for 18 function-retaining spin labels coupled to the PH domain, and for calibration spin labels coupled to phospholipids. The resulting depth parameters, together with the known high resolution structure of the co-complex between GRP1 PH domain and the PIP(3 headgroup, provide sufficient constraints to define an optimized, self-consistent membrane docking geometry. In this optimized geometry the PH domain engulfs the PIP(3 headgroup with minimal bilayer penetration, yielding the shallowest membrane position yet described for a lipid binding domain. This binding interaction displaces the PIP(3 headgroup from its lowest energy position and orientation in the bilayer, but the headgroup remains within its energetically accessible depth and angular ranges. Finally, the optimized docking geometry explains previous biophysical findings including mutations observed to disrupt membrane binding, and the rapid lateral

  5. Behavior of /sup 15/N-labelled amino acids in germinated corn

    Energy Technology Data Exchange (ETDEWEB)

    Samukawa, K; Yamaguchi, M [Osaka Prefectural Univ., Sakai (Japan). Coll. of Agriculture

    1979-06-01

    By investigating the rise and fall of /sup 15/N-labelled amino acids in germinated corns, the behavior of amino radicals in free amino acids, the influence of the hydrolysis products of stored proteins on free amino acids and the change from heterotrophy to autotrophy of seeds were clarified. The amount of amino acid production depending on external nitrogen was very small in the early period of germination. /sup 15/N incorporation into proline was not observed in the early period of germination, which suggested that the proline may be nitrogen-storing source. Most of the amino-state nitrogen of asparagine accumulated at the time of germination was internal nitrogen, and this fact suggested that aspartic acid serve as the acceptor of ammonia produced in the early stage of germination. /sup 15/N content increased significantly on 9 th day after germination, and decreased on 12 th day. These facts prove that there are always active decomposition and production of protein in plant body.

  6. Preparation of [3beta-3H] labeled bile acids and bile alcohols

    International Nuclear Information System (INIS)

    Dayal, B.; Baga, E.; Tint, G.S.; Shefer, S.; Salen, G.

    1979-01-01

    [3beta-3H]-bile acids and bile alcohols may be useful for metabolic studies in man and animals because the 3-position is invulnerable to bacterial attack. A number of tritium labeled bile acids and bile alcohols were prepared by selective oxidation of the hydroxyl group at carbon-3 followed by reduction with NaBT4. In each case, the bile acids and bile alcohols epimeric at carbon-3 were resolved by analytical and preparative thin-layer chromatography and characterized by gas liquid chromatography. The average yield was 60 to 65% and specific activities of the final products were in the range of 7.4 x 10 7 dpm/mg

  7. Labeling of amino acid (L-Glutamine) with technetium-99m and biological evaluation

    International Nuclear Information System (INIS)

    Ahmed, S. S.; Abass, S. A. E.; Karim, L. M.; Risan, R. H.; Abdulkarim, H. M.; Zia, M. A.; Manjy, A.N.; Hamed, S. A.

    2012-12-01

    The study of labeling of some amino acid 9 9mT c has been carried before (1, 2). Some were found to be chemically valuable, while some others had no clinical value although, they provided US with knowledge on the mechanism of labeling and biodistribution. In this paper we experimented the possibility of labeling L-Glutamine with Tc 9 '9 m and studied its biological behavior the study revealed that the optimal pH for the formation of higher percentage of the complex is about (2.5-2.55). Biodistribution carried in balb/c mice showed that the complex accumulates in soft tissue of the abdomen. This fining may indicate good clinical value in diagnosis of soft tissue tumors of lesion. (Author)

  8. Preparation of H3-labelled methyl ethers of saturated fatty acids by heterogeneous catalytic isotope exchange in solution with gaseous tritium

    International Nuclear Information System (INIS)

    Shevchenko, V.P.; Myasoedov, N.F.

    1980-01-01

    A simple method of preparing 3 H-labelled methyl ethers of saturated fatty acids in the dioxane solution using the method of isotopic heterogenous catalytic exchange with gaseous tritium, is suggested. 3 H-labelled natural fatty acids (C 12 -C 18 ) are prepared by alkaline hydrolysis [ru

  9. Comparison of ionisation properties of aetma-labeled saccharides with common labels

    OpenAIRE

    Partyka, J. (Jan); Foret, F. (František)

    2015-01-01

    We have tested (2-aminoethyl)trimethylammonium (AETMA) as a label for analysis of oligosaccharides by capillary electrophoresis with electrospray (ESI) mass spectrometry detection and compared its performance to taurine, 2-aminobenzoic acid, 2-aminobenzamide and 8-aminopyrene-1,3,6-trisulfonic acid. The AETMA-labeled saccharides were provided higher ionization signals in positive mode than native sodium or ammonium adducts and equal or higher signals than saccharides labeled by the more commo...

  10. Site directed spin labeling studies of Escherichia coli dihydroorotate dehydrogenase N-terminal extension

    Energy Technology Data Exchange (ETDEWEB)

    Couto, Sheila G. [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, Av. Trabalhador Sao-carlense 400, C.P. 369, 13560-970, Sao Carlos, SP (Brazil); Grupo de Biofisica e Fisica Aplicada a Medicina, Instituto de Fisica, Universidade Federal de Goias, Campus Samambaia, C.P. 131, 74001-970, Goiania, GO (Brazil); Cristina Nonato, M. [Laboratorio de Cristalografia de Proteinas, Faculdade de Ciencias Farmaceuticas de Ribeirao Preto, Universidade de Sao Paulo, Av. do Cafe S/N, 14040-903, Ribeirao Preto, SP (Brazil); Costa-Filho, Antonio J., E-mail: ajcosta@ffclrp.usp.br [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, Av. Trabalhador Sao-carlense 400, C.P. 369, 13560-970, Sao Carlos, SP (Brazil); Departamento de Fisica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Av. Bandeirantes 3900, 14040-901, Ribeirao Preto, SP (Brazil)

    2011-10-28

    Highlights: Black-Right-Pointing-Pointer EcDHODH is a membrane-associated enzyme and a promising target for drug design. Black-Right-Pointing-Pointer Enzyme's N-terminal extension is responsible for membrane association. Black-Right-Pointing-Pointer N-terminal works as a molecular lid regulating access to the protein interior. -- Abstract: Dihydroorotate dehydrogenases (DHODHs) are enzymes that catalyze the fourth step of the de novo synthesis of pyrimidine nucleotides. In this reaction, DHODH converts dihydroorotate to orotate, using a flavine mononucleotide as a cofactor. Since the synthesis of nucleotides has different pathways in mammals as compared to parasites, DHODH has gained much attention as a promising target for drug design. Escherichia coli DHODH (EcDHODH) is a family 2 DHODH that interacts with cell membranes in order to promote catalysis. The membrane association is supposedly made via an extension found in the enzyme's N-terminal. In the present work, we used site directed spin labeling (SDSL) to specifically place a magnetic probe at positions 2, 5, 19, and 21 within the N-terminal and thus monitor, by using Electron Spin Resonance (ESR), dynamics and structural changes in this region in the presence of a membrane model system. Overall, our ESR spectra show that the N-terminal indeed binds to membranes and that it experiences a somewhat high flexibility that could be related to the role of this region as a molecular lid controlling the entrance of the enzyme's active site and thus allowing the enzyme to give access to quinones that are dispersed in the membrane and that are necessary for the catalysis.

  11. Dynamics of the amino acid and protein metabolism of laying hens after the application of 15N-labelled wheat protein. 7

    International Nuclear Information System (INIS)

    Gruhn, K.

    1988-01-01

    In a 15 N labelling experiment 12 colostomized laying hens received 15 N-labelled wheat with 14.37 atom-% 15 N excess ( 15 N') over 4 days. 3 hens each were butchered after 12 h, 36 h, 60 h and 108 h after the last 15 N' application. The gastrointestinal tract was divided into 3 parts (esophagus with crop and gizzard as well as glandular stomach, small intestine, large intestine). These parts and the pancreas were hydrolyzed with 6 N HCl and the individual basic as well as the sum of acid and neutral amino acids were determined in the hydrolyzed fractions. In addition, the amino acids and peptides were determined in the TCA soluble N fraction. The atom-% 15 N' was determined in the individual amino acid and peptide fractions. The labelling of the basic amino acids in the individual tract segments was lower than in the acid and neutral amino acids. In comparison to the peptides, a higher atom-% 15 N' could be determined in the free amino acids. (author)

  12. Selective solubilization of membrane proteins differentially labeled by p-chloromercuribenzenesulfonic acid in the presence of sucrose

    International Nuclear Information System (INIS)

    M'Batchi, B.; Pichelin, D.; Delrot, S.

    1987-01-01

    Broadbean (Vicia faba L.) leaf discs have been incubated with the slowly permeant thiol reagent [ 203 Hg]-para-chloromercuribenzenesulfonic acid (PCMBS) in the presence or in the absence of sucrose, and the release of PCMBS-labeled proteins has been monitored in media containing various concentrations of urea, ethylene glycol-bis-(β-aminoethyl ether)-N, N, N', N'-tetraacetic acid (EGTA), sodium cholate, sodium dodecyl sulfate, Triton X-100, octylglucoside or (3-[3-cholamidopropyl)-dimethylammonio] 1-propane-sulfonate)(CHAPS). The proteins differentially labeled by PCMBS in the presence of sucrose which, on the basis of previous results, are assumed to included the sucrose carrier, were preferentially solubilized by 1% CHAPS, 1% octylglucoside, or 1% Triton X-100. Other PCMBS-labeled proteins (background proteins) could be partially removed by EGTA, urea, or 0.1% cholate. Sequential treatment by 10 mM EGTA and 1% CHAPS was found to give a fraction highly enriched in the differentially labeled proteins. Analysis of the specific activity of microsomal pellets suggests that the results obtained with leaf discs give a good account of what is occurring at the plasma membrane level. These data, which suggest that the proteins differentially labeled, by PCMBS in the presence of sucrose are intrinsic membrane proteins, can be used to solubilize these proteins from microsomal fractions

  13. Influence of the glutamic acid content of the diet on the catabolisc rate of labelled glutamic acid in rats. 1

    International Nuclear Information System (INIS)

    Bergner, H.; Wilke, A.; Simon, O.; Wolf, E.

    1984-01-01

    Male rats received in 8 groups of 10 animals each for a period of 7 days 7 synthetic diets and one semisynthetic diet on maintenance requirement level. A L-amino acid mixture corresponding to the pattern of egg protein without glutamic acid was the protein source of the synthetic diets. Glutamic acid was supplemented successively from 0 to 58 mol-% of the total amino acid content. The crude protein source of diet 8 was whole-egg powder. On the 8th day of experiment 5 animals per group were labelled by intragastric infusion with 14 C-glutamic acid. During the following 24 hours the excretion of CO 2 and 14 CO 2 was measured. Throughout the experimental feeding body weight was relative constant, however, when the synthetic diets were fed it was necessary to increase the daily amount of energy from 460 to 480 kJ/kg/sup 0.67/. The relative 14 CO 2 excretion within 24 hours was 68-75 % of the dose. However, the main part of the amount of radioactivity excreted during 24 hours was already found after 4 to 6 hours. Exponential functions calculated from the data of cumulative 14 CO 2 excretion suggest the existence of a fast process of 14 CO 2 formation directly from 14 C-glutamic acid, reaching a plateau within 2 hours and a slow process of oxidation of intermediates of glutamic acid metabolism, causing a continued 14 CO 2 formation even after 24 hours. The oxidation of 14 C-glutamic acid to CO 2 decreased 2 to 14 hours after labelling if the glutamic acid content of the diet increased. The same was found for the specific radioactivity of 14 CO 2 . A storage of intermediates of glutamic acid before degradation was assumed. (author)

  14. Central transport and distribution of labelled glutamic and aspartic acids to the cochlear nucleus in cats. An autoradiographic study

    Energy Technology Data Exchange (ETDEWEB)

    Kane, E S [University of Massachusetts Medical School, Worcester, MA (USA). Dept. of Anatomy

    1979-01-01

    Tritiated L-glutamic acid or L-aspartic acid was injected unilaterally into the cochleas of adult cats, and 4 h-7 days later the localization of label was studied by light-microscopic autoradiography in sections of the brain stem. Consistent differences in labelling after glutamate and after aspartate suggest differences in their uptake, metabolic conversion and/or transport to the cochlear nucleus by cochlear fibers. The morphological differences shown here agree with the distribution of those two amino acids in the cat cochlear nucleus as shown by microchemical analyses.

  15. Whole-body pharmacokinetics of HDAC inhibitor drugs, butyric acid, valproic acid and 4-phenylbutyric acid measured with carbon-11 labeled analogs by PET

    International Nuclear Information System (INIS)

    Kim, Sung Won; Hooker, Jacob M.; Otto, Nicola; Win, Khaing; Muench, Lisa; Shea, Colleen; Carter, Pauline; King, Payton; Reid, Alicia E.; Volkow, Nora D.; Fowler, Joanna S.

    2013-01-01

    The fatty acids, n-butyric acid (BA), 4-phenylbutyric acid (PBA) and valproic acid (VPA, 2-propylpentanoic acid) have been used for many years in the treatment of a variety of CNS and peripheral organ diseases including cancer. New information that these drugs alter epigenetic processes through their inhibition of histone deacetylases (HDACs) has renewed interest in their biodistribution and pharmacokinetics and the relationship of these properties to their therapeutic and side effect profiles. In order to determine the pharmacokinetics and biodistribution of these drugs in primates, we synthesized their carbon-11 labeled analogues and performed dynamic positron emission tomography (PET) in six female baboons over 90 min. The carbon-11 labeled carboxylic acids were prepared by using 11 CO 2 and the appropriate Grignard reagents. [ 11 C]BA was metabolized rapidly (only 20% of the total carbon-11 in plasma was parent compound at 5 min post injection) whereas for VPA and PBA 98% and 85% of the radioactivity were the unmetabolized compound at 30 min after their administration respectively. The brain uptake of all three carboxylic acids was very low ( VPA > PBA), which is consistent with the need for very high doses for therapeutic efficacy. Most of the radioactivity was excreted through the kidneys and accumulated in the bladder. However, the organ biodistribution between the drugs differed. [ 11 C]BA showed relatively high uptake in spleen and pancreas whereas [ 11 C]PBA showed high uptake in liver and heart. Notably, [ 11 C]VPA showed exceptionally high heart uptake possibly due to its involvement in lipid metabolism. The unique biodistribution of each of these drugs may be of relevance in understanding their therapeutic and side effect profile including their teratogenic effects

  16. Arterial spin-labelling perfusion MRI and outcome in neonates with hypoxic-ischemic encephalopathy

    International Nuclear Information System (INIS)

    Vis, Jill B. de; Hendrikse, Jeroen; Petersen, Esben T.; Vries, Linda S. de; Bel, Frank van; Alderliesten, Thomas; Negro, Simona; Groenendaal, Floris; Benders, Manon J.N.L.

    2015-01-01

    Hyperperfusion may be related to outcome in neonates with hypoxic-ischemic encephalopathy (HIE). The purpose of this study was to evaluate whether arterial spin labelling (ASL) perfusion is associated with outcome in neonates with HIE and to compare the predictive value of ASL MRI to known MRI predictive markers. Twenty-eight neonates diagnosed with HIE and assessed with MR imaging (conventional MRI, diffusion-weighted MRI, MR spectroscopy [MRS], and ASL MRI) were included. Perfusion in the basal ganglia and thalami was measured. Outcome at 9 or 18 months of age was scored as either adverse (death or cerebral palsy) or favourable. The median (range) perfusion in the basal ganglia and thalami (BGT) was 63 (28-108) ml/100 g/min in the neonates with adverse outcome and 28 (12-51) ml/100 g/min in the infants with favourable outcome (p 2 = 0.86, p < 0.001). Higher ASL perfusion values in neonates with HIE are associated with a worse neurodevelopmental outcome. A combination of the MRS and ASL MRI information is the best predictor of outcome. (orig.)

  17. Quantifying Cerebellum Grey Matter and White Matter Perfusion Using Pulsed Arterial Spin Labeling

    Science.gov (United States)

    Li, Xiufeng; Sarkar, Subhendra N.; Purdy, David E.; Briggs, Richard W.

    2014-01-01

    To facilitate quantification of cerebellum cerebral blood flow (CBF), studies were performed to systematically optimize arterial spin labeling (ASL) parameters for measuring cerebellum perfusion, segment cerebellum to obtain separate CBF values for grey matter (GM) and white matter (WM), and compare FAIR ASST to PICORE. Cerebellum GM and WM CBF were measured with optimized ASL parameters using FAIR ASST and PICORE in five subjects. Influence of volume averaging in voxels on cerebellar grey and white matter boundaries was minimized by high-probability threshold masks. Cerebellar CBF values determined by FAIR ASST were 43.8 ± 5.1 mL/100 g/min for GM and 27.6 ± 4.5 mL/100 g/min for WM. Quantitative perfusion studies indicated that CBF in cerebellum GM is 1.6 times greater than that in cerebellum WM. Compared to PICORE, FAIR ASST produced similar CBF estimations but less subtraction error and lower temporal, spatial, and intersubject variability. These are important advantages for detecting group and/or condition differences in CBF values. PMID:24949416

  18. Quantifying Cerebellum Grey Matter and White Matter Perfusion Using Pulsed Arterial Spin Labeling

    Directory of Open Access Journals (Sweden)

    Xiufeng Li

    2014-01-01

    Full Text Available To facilitate quantification of cerebellum cerebral blood flow (CBF, studies were performed to systematically optimize arterial spin labeling (ASL parameters for measuring cerebellum perfusion, segment cerebellum to obtain separate CBF values for grey matter (GM and white matter (WM, and compare FAIR ASST to PICORE. Cerebellum GM and WM CBF were measured with optimized ASL parameters using FAIR ASST and PICORE in five subjects. Influence of volume averaging in voxels on cerebellar grey and white matter boundaries was minimized by high-probability threshold masks. Cerebellar CBF values determined by FAIR ASST were 43.8 ± 5.1 mL/100 g/min for GM and 27.6 ± 4.5 mL/100 g/min for WM. Quantitative perfusion studies indicated that CBF in cerebellum GM is 1.6 times greater than that in cerebellum WM. Compared to PICORE, FAIR ASST produced similar CBF estimations but less subtraction error and lower temporal, spatial, and intersubject variability. These are important advantages for detecting group and/or condition differences in CBF values.

  19. Quantifying cerebellum grey matter and white matter perfusion using pulsed arterial spin labeling.

    Science.gov (United States)

    Li, Xiufeng; Sarkar, Subhendra N; Purdy, David E; Briggs, Richard W

    2014-01-01

    To facilitate quantification of cerebellum cerebral blood flow (CBF), studies were performed to systematically optimize arterial spin labeling (ASL) parameters for measuring cerebellum perfusion, segment cerebellum to obtain separate CBF values for grey matter (GM) and white matter (WM), and compare FAIR ASST to PICORE. Cerebellum GM and WM CBF were measured with optimized ASL parameters using FAIR ASST and PICORE in five subjects. Influence of volume averaging in voxels on cerebellar grey and white matter boundaries was minimized by high-probability threshold masks. Cerebellar CBF values determined by FAIR ASST were 43.8 ± 5.1 mL/100 g/min for GM and 27.6 ± 4.5 mL/100 g/min for WM. Quantitative perfusion studies indicated that CBF in cerebellum GM is 1.6 times greater than that in cerebellum WM. Compared to PICORE, FAIR ASST produced similar CBF estimations but less subtraction error and lower temporal, spatial, and intersubject variability. These are important advantages for detecting group and/or condition differences in CBF values.

  20. Effect of temperature on thermal oxidation of palmitic acid studied by combination of EPR spin trapping technique and SPME-GC-MS/MS.

    Science.gov (United States)

    Chen, Hongjian; Wang, Yong; Cao, Peirang; Liu, Yuanfa

    2017-11-01

    Effect of temperatures on thermal oxidation of palmitic acid was studied by the combination of EPR and GC-MS/MS. DMPO was used as the spin trap. The experimental spectrum was simulated with alkyl and alkoxyl spin adducts. Total amount of spins, a parameter to indicate radical concentrations, detected at 180°C was nearly 10 times higher than that at 175°C. Besides, total amounts of spins detected at 180°C decreased rapidly because of the reaction between radical adducts and newly formed radicals. Signal intensities of alkyl radical adducts increased rapidly from 0.405 to 4.785 from 175°C to 180°C. Besides, more palmitic acid degraded to oxidized compounds from 175°C to 180°C than that of other temperature ranges. The C-C linkages between carbons 2 to 6 were easier to be oxidized at 180°C. The results all implied that oxidation rates of palmitic acid samples increased rapidly from 175°C to 180°C. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Incorporation of radio-labelled nucleic acid precursors by Theileria parva in bovine blood and salivary glands of Rhipicephalus appendiculatus ticks

    Energy Technology Data Exchange (ETDEWEB)

    Irvin, A.D.; Boarer, C.D.H.; Kurtti, T.J.; Ocama, J.G.R. (International Lab. for Research on Animal Diseases, Nairobi (Kenya))

    1981-12-01

    The uptake of radio-labelled nucleic acid precursors by blood and tick salivary gland forms of Theileria parva was studied. Piroplasms took up tritiated purines, particularly hypoxanthine, but not pyrimidines. Similar uptake was recorded by T. parva, both in tick saliva and in salivary glands maintained in vitro. Intermediate parasite stages were those most readily labelled in glands; this reflected active nucleic acid synthesis associated with rapid parasite division. Radio-labelling of T. parva in tick salivary glands could be of value in procedures used for concentrating and purifying theilerial sporozoites.

  2. Labeling of Tannic Acid with Technetium-99m for Diagnosis of Stomach Ulcer

    OpenAIRE

    Ibrahim, I. T.; El-Tawoosy, M.; Talaat, H. M.

    2011-01-01

    Tannic acid is a polyphenolic compound that could be labeled with technetium-99m. To produce about 90% yield of  99mTc-tannic acid in acidic media (pH), the conditions required were 150  g tin chloride, 30 min reaction time, and 200  g of the substrate. 99mTc-tannic was stable for 6 h. Oral biodistribution of 99mTc-tannic showed that it concentrated in the stomach ulcer to reach about 50% of the total injected dose at 1 h after orall administration. This concentration of 99mTc-tannic in s...

  3. New series of Tc-99m-labeled hepatobiliary tracers: N'-acyl- and N'-sulfonyl ethylenediamine-N,N-diacetic acids

    International Nuclear Information System (INIS)

    Karube, Y.; Kono, A.; Maeda, T.; Ohya, M.; Matsushima, Y.

    1981-01-01

    Various Tc-99m-labeled N'-substituted derivatives of ethylenediamine-N,N-diacetic acid (EDDA) are evaluated as hepatobiliary imaging agents. N-substituted aromatic acyl and aromatic sulfonyl derivatives of EDDA, labeled with Tc-99m, were administered to rabbits and golden hamsters, and the distribution indicated clearance by the hepatobiliary system. N'-aromatic sulfonyl EDDAs were labeled with Tc-99m by the SnCl 2 method with more than 99% yield. Clearance of Tc-99m-p-toluenesulfonyl EDDA from the blood and the liver was as rapid as that of TC-99m N-(2,6-diethylphenylcarbamoylmethyl)iminodiacetic acid (Tc-99m benzenesulfonyl EDDA lowered urinary excretion. It is concluded that the sulfonyl EDDAs provide a fruitful source for Tc-99m-labeled hepatobiliary radiopharmaceuticals

  4. Synthesis of a cleavable heterobifunctional photolabelling reagent: ring-labelled 3-((4-azidophenyl)dithio)propionic acid- sup 14 C

    Energy Technology Data Exchange (ETDEWEB)

    Ramaswami, Varadarajan (Carnegie-Mellon Univ., Pittsburgh, PA (USA). Dept. of Chemistry); Tirrell, D.A. (Massachusetts Univ., Amherst, MA (USA). Dept. of Polymer Science and Engineering)

    1989-08-01

    An efficient synthesis of ring-labelled 3-((4-azidophenyl)dithio)propionic acid-{sup 14}C is described. Chlorosulfonation of uniformly ring-labelled acetanilide-{sup 14}C followed by reductive dimerization of the sulfonyl chloride with HI afforded 4-acetamidophenyl disulfide. Hydrolysis and diazotization then gave 4-azidophenyl disulfide, which was converted to the title compound via the sulfur transfer reagent N-(4-azidophenylthio)phthalimide. The overall yield of 3-((4-azidophenyl)dithio)propionic acid-{sup 14}C was 22%. 3-((4-Azidophenyl)dithio)propionic acid-{sup 14}C is a cleavable heterobifunctional photolabelling reagent of potential utility in studies of biomembrane structure and intermacromolecular interaction. (author).

  5. Method to produce a ω-123I labelled fatty acid to be used as radio-pharmaceutical

    International Nuclear Information System (INIS)

    Feinendegen, L.E.; Freundlieb, C.; Machulla, J.; Stoecklin, G.; Vyska, K.

    1979-01-01

    The labelled fatty acids are used to investigate the circulation disturbances of the myocardium and the disturbance of the lipocatabolism in the myocardium. The activity is measured by an Anger camera. The fatty acid is obtained from ω-bromium fatty acid and separated chromatographically from the residual process products. Silica gel is used as separation column and a mixture of an alkane and addition of a polar acid solution, as carrier liquid. (DG) [de

  6. Norepinephrine metabolism in man using deuterium labeling: turnover 4-hydroxy-3-methoxymandelic acid

    Energy Technology Data Exchange (ETDEWEB)

    Mardh, G.; Sjoequist, B.; Anggard, E.

    1982-06-01

    4-Hydroxy-3-methoxymandelic acid (HMMA; VMA) labeled with three deuterium atoms was used to study the turnover and fate of HMMA following intravenous injection. Five healthy men were given a pulse dose of 5.0 mumol of labeled HMMA. Plasma and urinary levels of both endogenous and labeled HMMA were subsequently followed by gas chromatography-mass spectrometry using selected ion detection. The kinetic parameters were determined both with and without compensation for the pool expansion caused by the injection of labeled HMMA. The urinary recovery of labeled HMMA was 85 +/- 10% (mean +/- SD). No conversion of HMMA to 4-hydroxy-3-methoxyphenyl glycol (HMPG) occurred. The biological half-life of HMMA was 0.54 +/- 0.22 h. The apparent volume of distribution was 0.36 +/- 0.11 L/kg. The production rate or body turnover was 1.27 +/- 0.51 mumol HMMA/h and urinary excretion rate was 0.82 +/- 0.22 mumol/h. These results show that HMMA is turnover over rapidly in a relatively small volume of distribution and that, unlike HMPG, it is an end metabolite of norepinephrine in man.

  7. Two-step protein labeling by using lipoic acid ligase with norbornene substrates and subsequent inverse-electron demand Diels-Alder reaction.

    Science.gov (United States)

    Best, Marcel; Degen, Anna; Baalmann, Mathis; Schmidt, Tobias T; Wombacher, Richard

    2015-05-26

    Inverse-electron-demand Diels-Alder cycloaddition (DAinv ) between strained alkenes and tetrazines is a highly bio-orthogonal reaction that has been applied in the specific labeling of biomolecules. In this work we present a two-step labeling protocol for the site-specific labeling of proteins based on attachment of a highly stable norbornene derivative to a specific peptide sequence by using a mutant of the enzyme lipoic acid ligase A (LplA(W37V) ), followed by the covalent attachment of tetrazine-modified fluorophores to the norbornene moiety through the bio-orthogonal DAinv  . We investigated 15 different norbornene derivatives for their selective enzymatic attachment to a 13-residue lipoic acid acceptor peptide (LAP) by using a standardized HPLC protocol. Finally, we used this two-step labeling strategy to label proteins in cell lysates in a site-specific manner and performed cell-surface labeling on living cells. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Development of superior bone scintigraphic agent from a series of {sup 99m}Tc-labeled zoledronic acid derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Lin Jianguo [Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063 (China); Qiu Ling, E-mail: qiulingwx@gmail.com [Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063 (China); Cheng Wen [Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063 (China); Luo Shineng, E-mail: shineng914@yahoo.com.cn [Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063 (China); Xue Li; Zhang Shu [Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063 (China)

    2012-05-15

    Two novel zoledronic acid (ZL) derivatives, 1-hydroxy-4-(1H-imidazol-1-yl)butane-1,1-diyldiphosphonic acid (IBDP) and 1-hydroxy-5-(1H-imidazol-1-yl)pentane-1,1-diyldiphosphonic acid (IPeDP), were prepared and labeled with the radionuclide technetium-99m in a high labeling yield. In vitro stabilities of these radiolabeled complexes were measured by the radio-HPLC analysis as a function of time, which showed excellent stability with the radiochemical purity of over 95% at 6 h post preparation. Their in vivo biological performances were evaluated and compared with those of {sup 99m}Tc-ZL and {sup 99m}Tc-MDP (methylenediphosphonic acid). The biodistribution in mice and scintigraphic images of the rabbit showed that the tracer agent {sup 99m}Tc-IPeDP had highly selective uptake in the skeletal system and rapid clearance from the blood and soft tissues and an excellent scintigraphic image can be obtained in a shorter time post injection with clear visualization of the skeleton and low soft tissue activity. These preclinical studies suggest that {sup 99m}Tc-IPeDP would be a novel superior bone scintigraphic agent. - Highlights: Black-Right-Pointing-Pointer Two novel diphosphonic acids were labeled with the {sup 99m}Tc in high labeling yield. Black-Right-Pointing-Pointer {sup 99m}Tc-IPeDP had high uptake in skeletal system and rapid clearance from blood. Black-Right-Pointing-Pointer {sup 99m}Tc-IPeDP reveals attractive biological features as superior bone scanning agent.

  9. Folosirea spectrometrului RES ART-6 IFIN in studii cu markeri de spin

    International Nuclear Information System (INIS)

    Ionescu, M.S.; Strujan, V.; Frangopol, M.; Ciobanu, M.; Sholle, V.D.; Benga, Gh.; Frangopol, P.T.

    1981-06-01

    Characteristics of the ESR spectrometer ART-6, made at the Institute of Phzsics and Nuclear Engineering (IFIN), Magurele-Bucharest (sensitivity 3x10 11 spin/G, resolving power 100 mG, magnetic field stability 2x1q -5 , frequency stability 2x10 -6 ) are presented along with the instrumental parameters used in the study of spin labels, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and 3-methylene-5-(piperinide-N-methyl)-4-oxo-2,2,6,6-tetramethylpiperidine-1oxyl. These spin labels were used for the investigation of some biological membranes. 40 ref. (authors)

  10. Investigation on the distribution of tritium and carbon-14 in the amino acids of labelled green algae (Scenedesmus Quadricauda ssp.)

    International Nuclear Information System (INIS)

    Nuernberger, E.; Clausen, E.; Kistner, G.

    1982-01-01

    Green algae (Scenedesmus quadricauda ssp. subspicatus), labelled twice tritium and carbon-14, showed an incorporation of nuclides into the cell mass of 0.02% and 95%, respectively. The distribution of radioactivity in the individual amino acids was examined in a protein fraction with special emphasis on the essential amino acids in view of their following incorporation into the next link of the aquatic food chain (Daphnia). The highest values were found in glutamine and asparagine acids as well as in the essential amino acids leucine and arginine, which are amino acids with a relatively high amount of non exchangeable H-positions per molecule and, therefore, a relatively high and stable labelling. (author)

  11. The method for production of high purity carrier free ortophosphoric acid labeled with isotopes Phosphorus-32 and Phosphorus-33

    International Nuclear Information System (INIS)

    Abdukayumov, M.N.; Abdusalyamov, A.N.; Chistyakov, P.G.; Yuldashev, B.S.

    2001-01-01

    Extensive application for various radioactive isotopes was found in an extremity of the 20-Th century in a science and production. Labeled compounds are used with growing effectiveness in a molecular biology, gene engineering, medicine and other areas. Phosphorus-32 and Phosphorus-33 isotopes as a different labeled compounds that are used mainly in molecular biology are produced at the Radiopreparat enterprise of the Institute of Nuclear Physics of Academy of Sciences of Uzbekistan Republic. The quality of labeled preparations is very high. The specifications for above mentioned preparations corresponds to demands most of customers in different countries. P-32 or P-33 labeled orthophosphoric acid has high radiochemical purity (more than 99 %) and specific radioactivity close to theoretical. Orthophosphoric acid prepared by the described above method has radiochemical purity about 95 % and output of the target product 99%

  12. Use of flow scintillation analyzer combined with amino acid analyzer for measuring low-level radioactivity of tritium-labelled amino acids

    CERN Document Server

    Lukashina, E V; Fedoseev, V M; Ksenofontov, A L; Baratova, L A; Dobrov, E N

    2002-01-01

    Potential application of the Radiomatic 150TR Flow Scintillation Analyzer (Packard Instrument Co., USA) for measuring low radioactivity of tritium-labelled amino acids in eluate from the Amino Acid Analyzer 835 (Hitachi, Japan) was studied. Six scintillating cocktails were tested and the Hionic-Fluor and Ultima-Flo AP cocktails proved the most appropriate for flow measurement of radioactivity. Efficiency of tritium radioactivity recording under various conditions of analysis was determined. Under optimal conditions the lower detection limit for the Hionic-Fluor was 150, while for Ultima-Flo AP-100 decays/min in the peak of amino acid

  13. The incorporation of radio-labelled nucleic acid precursors by Theileria parva in bovine blood and salivary glands of Rhipicephalus appendiculatus ticks

    International Nuclear Information System (INIS)

    Irvin, A.D.; Boarer, C.D.H.; Kurtti, T.J.; Ocama, J.G.R.

    1981-01-01

    The uptake of radio-labelled nucleic acid precursors by blood and tick salivary gland forms of Theileria parva was studied. Piroplasms took up tritiated purines, particularly hypoxanthine, but not pyrimidines. Similar uptake was recorded by T. parva, both in tick saliva and in salivary glands maintained in vitro. Intermediate parasite stages were those most readily labelled in glands; this reflected active nucleic acid synthesis associated with rapid parasite division. Radio-labelling of T. parva in tick salivary glands could be of value in procedures used for concentrating and purifying theilerial sporozoites. (author)

  14. The QUASAR reproducibility study, Part II: Results from a multi center Arterial Spin Labeling test-retest Study

    Science.gov (United States)

    Petersen, Esben Thade; Mouridsen, Kim; Golay, Xavier

    2009-01-01

    Arterial Spin Labeling (ASL) is a method to measure perfusion using magnetically labeled blood water as an endogenous tracer. Being fully non-invasive, this technique is attractive for longitudinal studies of cerebral blood flow in healthy and diseased individuals, or as a surrogate marker of metabolism. So far, ASL has been restricted mostly to specialist centers due to a generally low SNR of the method and potential issues with user-dependent analysis needed to obtain quantitative measurement of cerebral blood flow (CBF). Here, we evaluated a particular implementation of ASL (called Quantitative STAR labeling of Arterial Regions or QUASAR), a method providing user independent quantification of CBF in a large test-retest study across sites from around the world, dubbed “The QUASAR reproducibility study”. Altogether, 28 sites located in Asia, Europe and North America participated and a total of 284 healthy volunteers were scanned. Minimal operator dependence was assured by using an automatic planning tool and its accuracy and potential usefulness in multi-center trials was evaluated as well. Accurate repositioning between sessions was achieved with the automatic planning tool showing mean displacements of 1.87±0.95mm and rotations of 1.56±0.66°. Mean gray matter CBF was 47.4±7.5 [ml/100g/min] with a between subject standard variation SDb = 5.5 [ml/100g/min] and a within subject standard deviation SDw = 4.7 [ml/100g/min]. The corresponding repeatability was 13.0 [ml/100g/min] and was found to be within the range of previous studies. PMID:19660557

  15. The QUASAR reproducibility study, Part II: Results from a multi-center Arterial Spin Labeling test-retest study.

    Science.gov (United States)

    Petersen, Esben Thade; Mouridsen, Kim; Golay, Xavier

    2010-01-01

    Arterial Spin Labeling (ASL) is a method to measure perfusion using magnetically labeled blood water as an endogenous tracer. Being fully non-invasive, this technique is attractive for longitudinal studies of cerebral blood flow in healthy and diseased individuals, or as a surrogate marker of metabolism. So far, ASL has been restricted mostly to specialist centers due to a generally low SNR of the method and potential issues with user-dependent analysis needed to obtain quantitative measurement of cerebral blood flow (CBF). Here, we evaluated a particular implementation of ASL (called Quantitative STAR labeling of Arterial Regions or QUASAR), a method providing user independent quantification of CBF in a large test-retest study across sites from around the world, dubbed "The QUASAR reproducibility study". Altogether, 28 sites located in Asia, Europe and North America participated and a total of 284 healthy volunteers were scanned. Minimal operator dependence was assured by using an automatic planning tool and its accuracy and potential usefulness in multi-center trials was evaluated as well. Accurate repositioning between sessions was achieved with the automatic planning tool showing mean displacements of 1.87+/-0.95 mm and rotations of 1.56+/-0.66 degrees . Mean gray matter CBF was 47.4+/-7.5 [ml/100 g/min] with a between-subject standard variation SD(b)=5.5 [ml/100 g/min] and a within-subject standard deviation SD(w)=4.7 [ml/100 g/min]. The corresponding repeatability was 13.0 [ml/100 g/min] and was found to be within the range of previous studies.

  16. Stability of MR brain-perfusion measurement using arterial spin labeling

    Energy Technology Data Exchange (ETDEWEB)

    Petr, Jan; Hofheinz, Frank; Platzek, Ivan; Schramm, Georg; Van Den Hoff, Jorg [Helmholtz-Center Dresden-Rossendorf, PET Center, Institute of Radiopharmaceutical Cancer Research (Germany)

    2015-05-18

    Arterial spin labeling (ASL) is an MR technique for assessment of cerebral blood flow (CBF) that does not require use of contrast agents which makes it a less invasive alternative to the 15O-H2O-PET measurement. The repeatability of ASL has been studied extensively but mainly in young healthy volunteers. We have tested repeatability of ASL under realistic clinical conditions in elderly brain tumor patients acquired with a Philips Ingenuity TF PET/MR in the context of an ongoing 11C-Methionine PET/MR study. Twenty three patients (age 54.8±13.0 y) were scanned on two or more session. The patients underwent 6 weeks of concurrent radiochemotherapy with Temozolomide between the first session and second measurement. The mean relative difference of gray matter CBF was 18.6% between the first two session and 13.0% for the second session and further on. The mean gray matter CBF was 46.6±7.2 mL/min/100 g on the first sessions and there was a significant decrease of 9.8% between first and second session (p=0.027). In summary, the ASL presents measurement of CBF with reasonable repeatability also in elderly patients under clinical conditions when it is not possible to control for all sources of variation. Significant decrease of CBF in healthy tissue was observed after the radiochemotherapy. Prospectively, the ASL data together with the also acquired 11C-Methionine PET will be evaluated regarding their separate and combined ability to predict patient outcome and effectiveness of the performed radiochemotherapy.

  17. Longitudinal Assessment of Renal Perfusion and Oxygenation in Transplant Donor-Recipient Pairs Using Arterial Spin Labeling and Blood Oxygen Level-Dependent Magnetic Resonance Imaging.

    Science.gov (United States)

    Niles, David J; Artz, Nathan S; Djamali, Arjang; Sadowski, Elizabeth A; Grist, Thomas M; Fain, Sean B

    2016-02-01

    The aims of this study were to assess renal function in kidney transplant recipients and their respective donors over 2 years using arterial spin labeling (ASL) and blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) and to prospectively evaluate the effect of losartan on functional MRI measures in recipients. The study included 15 matched pairs of renal transplant donors and recipients. Arterial spin labeling and BOLD MRI of the kidneys were performed on donors before transplant surgery (baseline) and on both donors and recipients at 3 months, 1 year, and 2 years after transplant. After 3 months, 7 of the 15 recipients were prescribed 25 to 50 mg/d losartan for the remainder of the study. A linear mixed-effects model was used to evaluate perfusion, R2*, estimated glomerular filtration rate, and fractional excretion of sodium for changes across time or associated with losartan treatment. In donors, cortical perfusion in the remaining kidney decreased by 50 ± 19 mL/min per 100 g (11.8%) between baseline and 2 years (P donors and to 14.6 ± 4.3 mL/min per 1.73 m (33.3%; P donors, and they indicate a potentially beneficial effect of losartan in recipients.

  18. Towards fully automated structure-based NMR resonance assignment of 15N-labeled proteins from automatically picked peaks

    KAUST Repository

    Jang, Richard; Gao, Xin; Li, Ming

    2011-01-01

    In NMR resonance assignment, an indispensable step in NMR protein studies, manually processed peaks from both N-labeled and C-labeled spectra are typically used as inputs. However, the use of homologous structures can allow one to use only N-labeled NMR data and avoid the added expense of using C-labeled data. We propose a novel integer programming framework for structure-based backbone resonance assignment using N-labeled data. The core consists of a pair of integer programming models: one for spin system forming and amino acid typing, and the other for backbone resonance assignment. The goal is to perform the assignment directly from spectra without any manual intervention via automatically picked peaks, which are much noisier than manually picked peaks, so methods must be error-tolerant. In the case of semi-automated/manually processed peak data, we compare our system with the Xiong-Pandurangan-Bailey- Kellogg's contact replacement (CR) method, which is the most error-tolerant method for structure-based resonance assignment. Our system, on average, reduces the error rate of the CR method by five folds on their data set. In addition, by using an iterative algorithm, our system has the added capability of using the NOESY data to correct assignment errors due to errors in predicting the amino acid and secondary structure type of each spin system. On a publicly available data set for human ubiquitin, where the typing accuracy is 83%, we achieve 91% accuracy, compared to the 59% accuracy obtained without correcting for such errors. In the case of automatically picked peaks, using assignment information from yeast ubiquitin, we achieve a fully automatic assignment with 97% accuracy. To our knowledge, this is the first system that can achieve fully automatic structure-based assignment directly from spectra. This has implications in NMR protein mutant studies, where the assignment step is repeated for each mutant. © Copyright 2011, Mary Ann Liebert, Inc.

  19. Towards fully automated structure-based NMR resonance assignment of 15N-labeled proteins from automatically picked peaks

    KAUST Repository

    Jang, Richard

    2011-03-01

    In NMR resonance assignment, an indispensable step in NMR protein studies, manually processed peaks from both N-labeled and C-labeled spectra are typically used as inputs. However, the use of homologous structures can allow one to use only N-labeled NMR data and avoid the added expense of using C-labeled data. We propose a novel integer programming framework for structure-based backbone resonance assignment using N-labeled data. The core consists of a pair of integer programming models: one for spin system forming and amino acid typing, and the other for backbone resonance assignment. The goal is to perform the assignment directly from spectra without any manual intervention via automatically picked peaks, which are much noisier than manually picked peaks, so methods must be error-tolerant. In the case of semi-automated/manually processed peak data, we compare our system with the Xiong-Pandurangan-Bailey- Kellogg\\'s contact replacement (CR) method, which is the most error-tolerant method for structure-based resonance assignment. Our system, on average, reduces the error rate of the CR method by five folds on their data set. In addition, by using an iterative algorithm, our system has the added capability of using the NOESY data to correct assignment errors due to errors in predicting the amino acid and secondary structure type of each spin system. On a publicly available data set for human ubiquitin, where the typing accuracy is 83%, we achieve 91% accuracy, compared to the 59% accuracy obtained without correcting for such errors. In the case of automatically picked peaks, using assignment information from yeast ubiquitin, we achieve a fully automatic assignment with 97% accuracy. To our knowledge, this is the first system that can achieve fully automatic structure-based assignment directly from spectra. This has implications in NMR protein mutant studies, where the assignment step is repeated for each mutant. © Copyright 2011, Mary Ann Liebert, Inc.

  20. New series of Tc-99m-labeled hepatobiliary tracers: N'-acyl- and N'-sulfonyl ethylenediamine-N,N-diacetic acids

    International Nuclear Information System (INIS)

    Karube, Y.; Kono, A.; Maeda, T.; Ohya, M.; Matsushima, Y.

    1981-01-01

    Various Tc-99m-labeled N'-substituted derivatives of ethylenediamine-N,N-diacetic acid (EDDA) are evaluated as hepatobiliary imaging agents. N'-substituted aromatic acyl and aromatic sulfonyl derivatives of EDDA, labeled with Tc-99m, were administered to rabbits and golden hamsters, and the distribution indicated clearance by the hepatobiliary system. N'-aromatic sulfonyl EDDAs were labeled with Tc-99m by the SnCl 2 method with more than 99% yield. Clearance of Tc-99m-p-toluenesulfonyl EDDA from the blood and the liver was as rapid as that of Tc-99m N-(2,6-diethylphenylcarbamoylmethyl)iminodiacetic acid (Tc-99m diethyl IDA). Substitution of a bulky group at the aromatic ring in Tc-99m benzene-sulfonyl EDDA lowered urinary excretion. It is concluded that the sulfonyl EDDAs provide a fruitful source for Tc-99m-labeled hepatobiliary radiopharmaceuticals

  1. Nucleic acid labeling with [3H]orotic acid and nucleotide profile in rats in protein deprivation, enteral and parenteral essential amino acid administration, and 5-fluorouracil treatment

    International Nuclear Information System (INIS)

    Jakobsson, B.; el Hag, I.A.; Andersson, M.; Christensson, P.I.; Stenram, U.

    1990-01-01

    Rats were fed a 0% casein diet for 1 week, with or without enteral or parenteral administration of essential amino acids, or a 25% casein diet, in one group supplemented with 5-fluorouracil treatment. Ninety minutes before sacrifice the rats were given a tracer of [3H]orotic acid. Incorporation into the acid soluble fraction, RNA, and DNA was determined in liver, small intestine, bone marrow, and kidney. Nucleotide profile was examined in liver and intestine. Protein deficiency caused inter alia a decrease in body weight; a decrease in RNA/DNA ratio and an increase in the specific RNA labeling in liver and kidney; an altered nucleotide profile in the liver; an increase in the nucleotide/DNA and RNA/DNA ratios and a decrease in the specific labeling of the acid soluble fraction, RNA, and DNA in the bone marrow. These changes were prevented to the same extent by giving essential amino acids, either orally or intravenously. The minor changes in intestinal nucleotide profile in protein deprivation were prevented to a slightly larger extent by amino acids orally than parenterally. 5-Fluorouracil treatment gave a decrease in the RNA/DNA ratio in the liver and kidney but an increase in the nucleotide/DNA and RNA/DNA ratios in the bone marrow. Nucleotide profiles were unaltered. The amount of DNA per gram of tissue decreased in bone marrow and increased in kidney. Parenteral administration per se resulted in almost no changes

  2. Synthesizing labeled compounds

    International Nuclear Information System (INIS)

    London, R.E.; Matwiyoff, N.A.; Unkefer, C.J.; Walker, T.E.

    1983-01-01

    A metabolic study is presented of the chemical reactions provided by isotopic labeling and NMR spectroscopy. Synthesis of 13 C-labeled D-glucose, a 6-carbon sugar, involves adding a labeled nitrile group to the 5-carbon sugar D-arabinose by reaction with labeled hydrogen cyanide. The product of this reaction is then reduced and hydrolyzed to a mixture of the labeled sugars. The two sugars are separated by absorption chromotography. The synthesis of 13 C-labeled L-tyrosine, an amino acid, is also presented

  3. Substantiation of rate setting of surface contamination with amino acids, labelled with tritium

    International Nuclear Information System (INIS)

    Zhesko, T.V.

    1987-01-01

    For rate setting of surface contamination with the wide-spread biogenic tritium compounds-protein predecessors-experimental study of skin absorption and skin deposit of amino acids labelled with tritium is carried out on rats. While extrapolating data to people and calculating tolerable skin contamination with 3 H- amino acids, it is supposed that people arm skin, 100-500 cm 2 , has no defects and that the skin surface decontamination after radionuclide contact is carried out with a preparation, efficiency of which is not less than 97%. The value of tolerable skin absorption of tritium amino acids, being 110-550 MBq/year or 4.8 kBq/cm 2 per one working day, is calculated

  4. 15N-labelled pyrazines of triterpenic acids

    International Nuclear Information System (INIS)

    Vlk, Martin; Micolova, Petra; Sarek, Jan

    2016-01-01

    Triterpenoid pyrazines from our research group were found selectively cytotoxic on several cancer cell lines with IC 50 in low micromolar range. This sparked our interest in preparing their labeled analogs for metabolic studies. In this work, we prepared a set of non-labeled pyrazines from seven triterpenoid skeletal types along with their 15 N labelled analogs. In this work, we present the synthesis and characterization of the target 15 N labelled pyrazines. Currently, these compounds are being studied in complex metabolic studies. (author)

  5. Nanoscale spin sensing in artificial cell membranes

    International Nuclear Information System (INIS)

    Simpson David

    2014-01-01

    The use of the nitrogen-vacancy (NV) centre in diamond as a single spin sensor or magnetometer has attracted considerable interest in recent years because of its unique combination of sensitivity, nanoscale resolution, and optical initialisation and readout at room temperature. Nanodiamonds in particular hold great promise as an optical magnetometer probe for bio applications. In this work we employ nanodiamonds containing single NV spins to detect freely diffusing Mn2+ ions by detecting changes in the transverse relaxation time (T2) of the single spin probe. We also report the detection of gadolinium spin labels present in an artificial cell membrane by measuring changes in the longitudinal relaxation time (T1) of the probe. (author)

  6. Influence of diet on the incorporation of labelled amino acids in muscles of calves

    International Nuclear Information System (INIS)

    Kumar, P.; Hansen, R.J.; Black, A.L.

    1974-01-01

    Experiments were conducted to study the influence of diet on the incorporation of labelled amino acids into the semitendinosus and biceps femoris muscles of calves after 48 h administration of isotope through jugular vein. 14 C or 3 H-labelled tyrosine and 14 C or 3 H-histidine were used as tracers. The results suggest that the incorporation into myofibrillar protein fraction of both the muscles was at least two fold greater on good diets as compared to all forage ration. Similar trend was also recorded with the plasma protein fraction at both 24 and 48 h after injection. (author)

  7. Influence of diet on the incorporation of labelled amino acids in muscles of calves

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, P; Hansen, R J; Black, A L [California Univ., Davis (USA). Dept. of Physiological Sciences

    1974-12-01

    Experiments were conducted to study the influence of diet on the incorporation of labeled amino acids into the semitendinosus and biceps femoris muscles of calves after 48 h administration of isotope through jugular vein. /sup 14/C or /sup 3/H-labelled tyrosine and /sup 14/C or /sup 3/H-histidine were used as tracers. The results suggest that the incorporation into myofibrillar protein fraction of both the muscles was at least two fold greater on good diets as compared to all forage ration. Similar trend was also recorded with the plasma protein fraction at both 24 and 48 h after injection.

  8. A general procedure for isotopic (deuterium) labelling of non-steroidal antiinflammatory 2-arylpropionic acids

    International Nuclear Information System (INIS)

    Castell, J.V.; Martinez, L.A.; Universidad Politecnica de Valencia; Miranda, M.A.; Tarrega, Pilar

    1994-01-01

    Alkaline treatment of nonsteroidal antiinflammatory 2-arylpropionic acids in deuterium oxide led in all cases to isotopic exchange of the proton located at the α-position of the side chain. Monodeuteration was observed in the case of carprofen, ibuprofen, ketoprofen, fenoprofen, flurbiprofen and naproxen. Additional exchange of one or two protons of the heterocyclic ring occurred in indoprofen, suprofen and tiaprofenic acid. The isotopic labelling survived under the conditions required to perform in vitro photoallergic studies (photolysis in non-deuterated aqueous media). (Author)

  9. A general procedure for isotopic (deuterium) labelling of non-steroidal antiinflammatory 2-arylpropionic acids

    Energy Technology Data Exchange (ETDEWEB)

    Castell, J.V. (Valencia Univ. Hospital (Spain). Centro de Investigacion); Martinez, L.A. (Valencia Univ. Hospital (Spain). Centro de Investigacion Universidad Politecnica de Valencia (Spain). Dept. de Quimica); Miranda, M.A.; Tarrega, Pilar (Universidad Politecnica de Valencia (Spain). Dept. de Quimica)

    1994-01-01

    Alkaline treatment of nonsteroidal antiinflammatory 2-arylpropionic acids in deuterium oxide led in all cases to isotopic exchange of the proton located at the [alpha]-position of the side chain. Monodeuteration was observed in the case of carprofen, ibuprofen, ketoprofen, fenoprofen, flurbiprofen and naproxen. Additional exchange of one or two protons of the heterocyclic ring occurred in indoprofen, suprofen and tiaprofenic acid. The isotopic labelling survived under the conditions required to perform in vitro photoallergic studies (photolysis in non-deuterated aqueous media). (Author).

  10. Free fatty acids and esters can be immobilized by receptor rich membranes from torpedo marmorata but not phospholipid acyl chains

    NARCIS (Netherlands)

    Rousselet, A.; Devaux, P.F.; Wirtz, K.W.A.

    1979-01-01

    A long chain spin labeled fatty acid and the corresponding ester have been introduced into receptor rich membranes from Torpedo Marmorata. Superimposed to a mobile component, typical of the lipid phase, a strongly immobilized component is seen on the ESR spectra, both at low temperature (−4°C) and

  11. Synthesis of isotopically labelled salicylates

    International Nuclear Information System (INIS)

    Hawkins, D.R.; Pryor, R.W.

    1981-01-01

    [ 13 C-carboxyl]Salicylic acid has been prepared by carbonation of 2-benzyloxybromobenzene followed by reductive debenzylation. Deuterium and tritium labelled salicylic acid and 2 H 2 / 13 C-salicylic acid were prepared by reduction of the 3,5-dibromo derivatives using Raney Ni-Al. Deuterium labelled salicylic acid containing up to four deuterium atoms was prepared by catalytic exchange with Raney Ni-Al in 5% NaOD/D 2 O. (author)

  12. Dynamics of amino acid and protein metabolism of laying hens after the application of 15N-labelled wheat protein. 1

    International Nuclear Information System (INIS)

    Hennig, A.; Gruhn, K.; Kirchner, E.

    1987-01-01

    In a 6-day preliminary period with a pelleted ration 12 colostomized laying hybrids received 15 N-labelled wheat protein over 4 days. The labelling of the wheat was 14.37 atom-% 15 N excess ( 15 N'). During the 4-day application of 15 N-labelled wheat protein each hen consumed 12.08 g N, 3.52 g lysine, 2.12 g histidine, 4.41 g arginine, of which were 540 mg 15 N', 18.1 mg lysine 15 N', 21.5 mg histidine 15 N' and 47.9 mg arginine 15 N'. Heavy nitrogen was determined in urine and its uric acid N in the daily urine samples of the individual animals. The average daily urine N excretion was 54% of the total nitrogen consumed with the ration. The labelling of the urine N reached a plateau on the fourth day of the experiment with 3.2 atom-% 15 N'. On an average of the total experiment the quota of heavy nitrogen of the uric acid in the total 15 N' of the urine was 83.4% and that of uric acid nitrogen in the total urine nitrogen 80.8%. (author)

  13. A facile synthesis of δ-aminolevulinic acid (ALA) regio-selectively labeled with 13C and direct observation of enzymatic transformation from ALA to porphobilinogen (PBG)

    International Nuclear Information System (INIS)

    Kurumaya, Katsuyuki; Okazaki, Takeo; Seido, Nobuo; Akasaka, Yuzuru; Kawajiri, Yoshiki; Kajiwara, Masahiro; Kondo, Masao

    1989-01-01

    δ-Aminolevulinic acid (ALA), labeled with 13 C at position 1, 2, 3, 4, or 5, was synthesized from 13 C-labeled glycine, Meldrum's acid, or bromoacetate. The latter compounds were prepared from 13 C-sodium acetate or 13 C-acetic acid. Enzymatic transformation from ALA to porphobilinogen (PBG) was directly observed by 13 C-NMR. (author)

  14. Optimization of amino acid type-specific 13C and 15N labeling for the backbone assignment of membrane proteins by solution- and solid-state NMR with the UPLABEL algorithm

    International Nuclear Information System (INIS)

    Hefke, Frederik; Bagaria, Anurag; Reckel, Sina; Ullrich, Sandra Johanna; Dötsch, Volker; Glaubitz, Clemens; Güntert, Peter

    2011-01-01

    We present a computational method for finding optimal labeling patterns for the backbone assignment of membrane proteins and other large proteins that cannot be assigned by conventional strategies. Following the approach of Kainosho and Tsuji (Biochemistry 21:6273–6279 (1982)), types of amino acids are labeled with 13 C or/and 15 N such that cross peaks between 13 CO(i – 1) and 15 NH(i) result only for pairs of sequentially adjacent amino acids of which the first is labeled with 13 C and the second with 15 N. In this way, unambiguous sequence-specific assignments can be obtained for unique pairs of amino acids that occur exactly once in the sequence of the protein. To be practical, it is crucial to limit the number of differently labeled protein samples that have to be prepared while obtaining an optimal extent of labeled unique amino acid pairs. Our computer algorithm UPLABEL for optimal unique pair labeling, implemented in the program CYANA and in a standalone program, and also available through a web portal, uses combinatorial optimization to find for a given amino acid sequence labeling patterns that maximize the number of unique pair assignments with a minimal number of differently labeled protein samples. Various auxiliary conditions, including labeled amino acid availability and price, previously known partial assignments, and sequence regions of particular interest can be taken into account when determining optimal amino acid type-specific labeling patterns. The method is illustrated for the assignment of the human G-protein coupled receptor bradykinin B2 (B 2 R) and applied as a starting point for the backbone assignment of the membrane protein proteorhodopsin.

  15. Tropanol esters of metallocene carboxylic acids. Syntheses, labelling with 103Ru and sup(103m)Rh and organ distribution

    International Nuclear Information System (INIS)

    Wenzel, M.; Wu, Y.

    1988-01-01

    The tropanol esters of the carboxylic acids of ferrocene, 103 Ru-ruthenocene and sup(103m)Rh-rhodocinium were synthezised. The organ distribution of the 103 Ru or sup(103m)Rh labelled tropanol-esters were investigated. Only the 103 Ru labelled ester showed a high heart/blood ratio. (author)

  16. Fluorescently labeled bionanotransporters of nucleic acid based on carbon nanotubes

    International Nuclear Information System (INIS)

    Novopashina, D.S.; Apartsin, E.K.; Venyaminova, A.G.

    2012-01-01

    We propose an approach to the design of a new type of hybrids of oligonucleotides with fluorescein-functionalized single-walled carbon nanotubes. The approach is based on stacking interactions of functionalized nanotubes with pyrene residues in conjugates of oligonucleotides. The amino- and fluorescein-modified single walled carbon nanotubes are obtained, and their physico-chemical properties are investigated. The effect of the functionalization type of carbon nanotubes on the efficacy of the sorption of pyrene conjugates of oligonucleotides was examined. The proposed noncovalent hybrids of fluorescein-labeled carbon nanotubes with oligonucleotides may be used for the intracellular transport of functional nucleic acids.

  17. Enhancement of automated blood flow estimates (ENABLE) from arterial spin-labeled MRI.

    Science.gov (United States)

    Shirzadi, Zahra; Stefanovic, Bojana; Chappell, Michael A; Ramirez, Joel; Schwindt, Graeme; Masellis, Mario; Black, Sandra E; MacIntosh, Bradley J

    2018-03-01

    To validate a multiparametric automated algorithm-ENhancement of Automated Blood fLow Estimates (ENABLE)-that identifies useful and poor arterial spin-labeled (ASL) difference images in multiple postlabeling delay (PLD) acquisitions and thereby improve clinical ASL. ENABLE is a sort/check algorithm that uses a linear combination of ASL quality features. ENABLE uses simulations to determine quality weighting factors based on an unconstrained nonlinear optimization. We acquired a set of 6-PLD ASL images with 1.5T or 3.0T systems among 98 healthy elderly and adults with mild cognitive impairment or dementia. We contrasted signal-to-noise ratio (SNR) of cerebral blood flow (CBF) images obtained with ENABLE vs. conventional ASL analysis. In a subgroup, we validated our CBF estimates with single-photon emission computed tomography (SPECT) CBF images. ENABLE produced significantly increased SNR compared to a conventional ASL analysis (Wilcoxon signed-rank test, P Wilcoxon signed-rank test, P < 0.0001) and this similarity was strongly related to ASL SNR (t = 24, P < 0.0001). These findings suggest that ENABLE improves CBF image quality from multiple PLD ASL in dementia cohorts at either 1.5T or 3.0T, achieved by multiparametric quality features that guided postprocessing of dementia ASL. 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:647-655. © 2017 International Society for Magnetic Resonance in Medicine.

  18. Facile syntheses of isotope-labeled chiral octahydroindole-2-carboxylic acid and its N-methyl analog

    International Nuclear Information System (INIS)

    Yinsheng Zhang

    2012-01-01

    We have synthesized deuterium and carbon-14 labeled enantiomerically pure octahydroindole-2-carboxylic acid (PD0140417), N-methyl octahydroindole-2-carboxylic acid (PD0348183) and their racemic analogs (PD0108405 and PD0338055). [ring-U- 14 C]PD0140417 was prepared from [ring-U- 14 C]benzoic acid in a seven-step synthesis in 6.2% overall radiochemical yield. [ 14 C]PD0348183 was prepared from [ 14 C]BaCO 3 in a five-step synthesis in 16% radiochemical yield. Additionally, [D]PD0108405 and [D]PD0338055 were synthesized by direct platinum-catalyzed hydrogenation with deuterium gas. (author)

  19. Differential saturation study of radial and angular modulation mechanisms of electron spin--lattice relaxation for trapped hydrogen atoms in sulfuric acid glasses. [X radiation

    Energy Technology Data Exchange (ETDEWEB)

    Plonka, A; Kevan, L

    1976-11-01

    A differential ESR saturation study of allowed transitions and forbidden proton spin-flip satellite transitions for trapped hydrogen atoms in sulfuric acid glasses indicates that angular modulation dominates the spin-lattice relaxation mechanisms and suggests that the modulation arises from motion of the H atom.

  20. Uptake of 15N-labelled urea and 32P-labelled phosphate from acid-based urea phosphate and granular fertilizers

    International Nuclear Information System (INIS)

    Bole, J.B.

    1986-01-01

    The availability of nitrogen and phosphorus in fertilizer products labelled with both 32 P and 15 N was measured in a growth chamber experiment. The uptake of N and P by soft white spring wheat (Triticum aestivum L.) from a solution of acid urea phosphate fertilizer did not differ significantly from that of a mixture of granular urea and monammonium phosphate fertilizer. The fertilizer-P uptake efficiency of both sources was higher in a neutral soil than in acid or calcareous soils. Banding either fertilizer increased the uptake of fertilizer P compared with sources mixed with the soil, but did not significantly affect fertilizer-N uptake. The increase in fertilizer-P efficiency due to banding was significantly greater for the urea-monammonium phosphate than for the acid urea phosphate solution. Banding fertilizer did not increase the uptake of fertilizer P in the calcareous soil, and decreased the uptake of fertilizer N in that soil compared with mixed treatments. It is suggested that soluble Ca formed from the reaction of acid with naturally occurring lime may have reduced the availability of fertilizer P in the band

  1. Sandwich nucleic acid hybridization: a method with a universally usable labeled probe for various specific tests

    International Nuclear Information System (INIS)

    Wolf, H.; Leser, U.; Haus, M.; Gu, S.Y.; Pathmanathan, R.

    1986-01-01

    The use of recombinant m13 phages as hybridization probes offers a considerable advantage over the commonly used recombinant plasmids as the preparation of the DNA probe is very simple and it can easily be labeled directly, e.g. with isotopes with long half-life like 125 I and used for hybridization. However, as the application of nucleic acid hybridization for diagnostic and epidemiological purposes becomes almost unavoidable, the logistic problems of keeping numerous individually labeled hybridization probes increase considerably and may reach prohibitory levels in less well-equipped laboratories. In a new sandwich technique, the first step involves hybridization with an unlabeled recombinant m13 DNA carrying an insert of the desired specificity. In a second step a universally usable labeled probe directed against the m13 part of the recombinant phage DNA is applied. This reduces considerably the problem of preparing and keeping multiple labeled probes in stock. (Auth.)

  2. Synthesis of positron labeled photoactive compounds: 18F labeled aryl azides for positron labeling of biochemical molecules

    International Nuclear Information System (INIS)

    Hashizume, Kazunari; Hashimoto, Naota; Miyake, Yoshihiro

    1995-01-01

    The authors have prepared various [ 18 F] fluorine labeled aryl azides as a novel photoactive compounds suitable for positron labeling of biochemical molecules. The introduction of fluorine substituents to aryl azides can be expected to have dramatic effects on their nature and reactivity toward photolysis. Positron labeled reagents for labeling proteins or peptides have recently attracted considerable attention due to their wide applicability in biochemistry and positron emission tomography (PET). Various labeled azide compounds are often used in biochemistry for radiolabeling biological molecules by photolysis, but there have been no reports on the preparation or use of fluorine-18 labeled azides. The authors now report a novel synthesis of 18 F-labeled aryl azides which will have wide application in the biochemistry and nuclear medicine as a means for 18 F-fluorine labeling for proteins, peptides, and nucleic acids. 2 tabs

  3. Summarization on the synthesis and radionuclide-labeling of peptide nucleic acid for an oligonucleotide analogue

    International Nuclear Information System (INIS)

    Song, Hongtao; Zhang, Huaming; Gao, Hui

    2009-04-01

    Peptide nucleic acid (PNA), which is one kind of antisense nucleic acid compounds and an oligonucleotide analogue that binds strongly to DNA and RNA in a sequence specific manner, has its unique advantages in the field of molecular diagnostics and treatment of diseases. Now, people gradually attach more importance to PNA. To optimize the application of PNA in genetic re- search and therapy, a great number of backbone modifications on the newly- type structures of PNA were synthesized to improve its physicochemical proper- ties, such as hybridization speciality, solubility in biofluid, or cell permeability. The modified PNA labeled with radionuclides, which can obtain the aim at specific target and minimal non-target trauma, has important role in research and application of tumorous genitherapy. Here a review on the basic synthesis idea and several primary synthetic methods of PNA analogs was given, and also correlative studies and expectation on the compounds belonging to PNA series labeled with radionuclides were included. (authors)

  4. Turnover of lipids labeled by I-123 phenylpentadecanoic acid (IP) compared to C-14 palmitic acid (P)

    International Nuclear Information System (INIS)

    Reske, S.N.; Sauer, W.; Breull, W.; Machulla, H.J.; Winkler, C.

    1984-01-01

    IP has been proposed for evaluation of cardiac lipid metabolism. To elucidate the metabolic fate of IP in more detail, the authors compared its uptake and turnover to that of P in lipids extracted from heart, lung, liver, spleen and kidneys of fasted anaesthetized Wistar rats after simultaneous i.v. tracer injection. The animals were sacrificed at different time intervals until 30 min. p.i. The organs were removed and lipids were extracted with chloroform/methanol. Fractional radioactivity distribution in lipids was analyzed by TLC. I-123 and C-14 radioactivity was assayed in free fatty acid (FFFA)-, phospholipid (PL)-, diglyceride (DG)-, and triglyceride (TG)-fraction in a -spectrometer and 20 weeks later in a liquid scintillation counter. Uptake and turnover patterns of IP-and P-labeled lipids were nearly identical. The authors conclude that IP and P label essentially the same lipids and exhibit very similar lipid turnover characteristics, indicating the feasibility of metabolic studies by means of IP as tracer for lipid metabolism

  5. Quantitative proteomics by amino acid labeling in C. elegans

    DEFF Research Database (Denmark)

    Fredens, Julius; Engholm-Keller, Kasper; Giessing, Anders

    2011-01-01

    We demonstrate labeling of Caenorhabditis elegans with heavy isotope-labeled lysine by feeding them with heavy isotope-labeled Escherichia coli. Using heavy isotope-labeled worms and quantitative proteomics methods, we identified several proteins that are regulated in response to loss or RNAi-med......-mediated knockdown of the nuclear hormone receptor 49 in C. elegans. The combined use of quantitative proteomics and selective gene knockdown is a powerful tool for C. elegans biology.......We demonstrate labeling of Caenorhabditis elegans with heavy isotope-labeled lysine by feeding them with heavy isotope-labeled Escherichia coli. Using heavy isotope-labeled worms and quantitative proteomics methods, we identified several proteins that are regulated in response to loss or RNAi...

  6. Synthesis and application of labelled growth regulators

    International Nuclear Information System (INIS)

    Shyutte, G.R.

    1982-01-01

    For the investigation of the metabolism both of phytoeffectors like herbicides and plant growth regulators such compounds are needed in radioactive labelled form. The synthesis of radioactive labelled fluorodifen, nitrofen, ethephon, diphenylic acetic acid, 2,4-dichlorophenoxyisobutyric acid, abscisic acid, hydroxybenzoic acids and different conjugates are described. Some examples of these compounds metabolism in plants are discussed [ru

  7. Labelling of castor oil for myocardial study

    International Nuclear Information System (INIS)

    Hallaba, E.; Al-Suhybani, A.; Zaki, F.S.; Abdullah, M.E.

    1985-01-01

    The labelling of castor oil, hydrolyzed castor oil and oleic acid by iodine monochloride and chloramine-T was investigated. The effect of iodinating agent and concentration of castor oil on labelling yield was studied. A comparative pharmacological study with analog aliphatic acids was carried out. Castor oil labelled with iodine monochloride concentrates in heart and liver in good proportion, better than other natural fatty acids and nearly equal to analog fatty acids. Infrared study revealed that the OH group in ricinoleic acid may protect the sup(125)I added across the double bond with minor changes in biochemical properties causing better extraction by muscle of the heart. (author)

  8. Rapid labeling of amino acid neurotransmitters with a fluorescent thiol in the presence of o-phthalaldehyde.

    Science.gov (United States)

    Maddukuri, Naveen; Zhang, Qiyang; Zhang, Ning; Gong, Maojun

    2017-02-01

    LIF detection often requires labeling of analytes with fluorophores; and fast fluorescent derivatization is valuable for high-throughput analysis with flow-gated CE. Here, we report a fast fluorescein-labeling scheme for amino acid neurotransmitters, which were then rapidly separated and detected in flow-gated CE. This scheme was based on the reaction between primary amines and o-phthalaldehyde in the presence of a fluorescent thiol, 2-((5-fluoresceinyl)aminocarbonyl)ethyl mercaptan (FACE-SH). The short reaction time (neurotransmitters by coupling in vitro microdialysis with online derivatization and flow-gated CE. It is also anticipated that this fluorophore tagging scheme would be valuable for on-chip labeling of proteins retained on support in SPE. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Operator spin foam models

    International Nuclear Information System (INIS)

    Bahr, Benjamin; Hellmann, Frank; Kaminski, Wojciech; Kisielowski, Marcin; Lewandowski, Jerzy

    2011-01-01

    The goal of this paper is to introduce a systematic approach to spin foams. We define operator spin foams, that is foams labelled by group representations and operators, as our main tool. A set of moves we define in the set of the operator spin foams (among other operations) allows us to split the faces and the edges of the foams. We assign to each operator spin foam a contracted operator, by using the contractions at the vertices and suitably adjusted face amplitudes. The emergence of the face amplitudes is the consequence of assuming the invariance of the contracted operator with respect to the moves. Next, we define spin foam models and consider the class of models assumed to be symmetric with respect to the moves we have introduced, and assuming their partition functions (state sums) are defined by the contracted operators. Briefly speaking, those operator spin foam models are invariant with respect to the cellular decomposition, and are sensitive only to the topology and colouring of the foam. Imposing an extra symmetry leads to a family we call natural operator spin foam models. This symmetry, combined with assumed invariance with respect to the edge splitting move, determines a complete characterization of a general natural model. It can be obtained by applying arbitrary (quantum) constraints on an arbitrary BF spin foam model. In particular, imposing suitable constraints on a spin(4) BF spin foam model is exactly the way we tend to view 4D quantum gravity, starting with the BC model and continuing with the Engle-Pereira-Rovelli-Livine (EPRL) or Freidel-Krasnov (FK) models. That makes our framework directly applicable to those models. Specifically, our operator spin foam framework can be translated into the language of spin foams and partition functions. Among our natural spin foam models there are the BF spin foam model, the BC model, and a model corresponding to the EPRL intertwiners. Our operator spin foam framework can also be used for more general spin

  10. Tests for the absorption of /sup 75/Se-labelled homocholic acid conjugated with taurine (/sup 75/Se-HCAT)

    Energy Technology Data Exchange (ETDEWEB)

    Schroth, H.J.; Berberich, R.; Mueller, K.P.; Feifel, G.; Ecker, K.W.

    1985-05-01

    The absorption of selenomethionine Se 75-labelled homocholic acid conjugated with taurine (/sup 75/-SE-HCAT) was tested in 46 patients. Retention measurements using (1) an uncollimated gamma camera and (2) a measuring arrangement similar to a human-body counter were compared in order to obtain a quantitative assessment of the absorption capacity of the terminal ileum for bile acids. The retention curve obtained after the oral administration of the /sup 75/Se-labelled bile-acid analogue showed a monoexponential decline; in the case of unimpaired absorption, the half-life was greater than 2.5 days. When more than 30 cm of the ileum had been eliminated by inflammatory infection or resection, the measured half-life was below 0.5 days due to malabsorption. We also performed a quantitative determination of the hepatic secretion of /sup 75/-Se-HCAT into the gall bladder. If more than 80% of the activity administered is found in the gall bladder, disturbed absorption of bile acids in the terminal ileum can be excluded. Values smaller than 80%, however, do not provide proof of disturbed absorption.

  11. Quantifying fluctuations of resting state networks using arterial spin labeling perfusion MRI.

    Science.gov (United States)

    Dai, Weiying; Varma, Gopal; Scheidegger, Rachel; Alsop, David C

    2016-03-01

    Blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) has been widely used to investigate spontaneous low-frequency signal fluctuations across brain resting state networks. However, BOLD only provides relative measures of signal fluctuations. Arterial Spin Labeling (ASL) MRI holds great potential for quantitative measurements of resting state network fluctuations. This study systematically quantified signal fluctuations of the large-scale resting state networks using ASL data from 20 healthy volunteers by separating them from global signal fluctuations and fluctuations caused by residual noise. Global ASL signal fluctuation was 7.59% ± 1.47% relative to the ASL baseline perfusion. Fluctuations of seven detected resting state networks vary from 2.96% ± 0.93% to 6.71% ± 2.35%. Fluctuations of networks and residual noise were 6.05% ± 1.18% and 6.78% ± 1.16% using 4-mm resolution ASL data applied with Gaussian smoothing kernel of 6mm. However, network fluctuations were reduced by 7.77% ± 1.56% while residual noise fluctuation was markedly reduced by 39.75% ± 2.90% when smoothing kernel of 12 mm was applied to the ASL data. Therefore, global and network fluctuations are the dominant structured noise sources in ASL data. Quantitative measurements of resting state networks may enable improved noise reduction and provide insights into the function of healthy and diseased brain. © The Author(s) 2015.

  12. A systematic analysis of backbone amide assignments achieved via combinatorial selective labelling of amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Jeremy Craven, C. [University of Sheffield, Department of Biotechnology and Molecular Biology (United Kingdom); Al-Owais, Moza; Parker, Martin J. [University of Leeds, Astbury Centre for Structural Molecular Biology, Institute of Molecular and Cellular Biology (United Kingdom)], E-mail: m.j.parker@leeds.ac.uk

    2007-06-15

    With the advent of high-yield cell-free expressions systems, many researchers are exploiting selective isotope labelling of amino acids to increase the efficiency and accuracy of the NMR assignment process. We developed recently a combinatorial selective labelling (CSL) method capable of yielding large numbers of residue-type and sequence-specific backbone amide assignments, which involves comparing cross-peak intensities in {sup 1}H-{sup 15}N HSQC and 2D {sup 1}H-{sup 15}N HNCO spectra collected for five samples containing different combinations of {sup 13}C- and {sup 15}N-labelled amino acids [Parker MJ, Aulton-Jones M, Hounslow A, Craven C J (2004) J Am Chem Soc 126:5020-5021]. In this paper we develop a robust method for establishing the reliability of these assignments. We have performed a detailed statistical analysis of the CSL data collected for a model system (the B1 domain of protein G from Streptococcus), developing a scoring method which allows the confidence in assignments to be assessed, and which enables the effects of overlap on assignment fidelity to be predicted. To further test the scoring method and also to assess the performance of CSL in relation to sample quality, we have applied the method to the CSL data collected for GFP in our previous study.

  13. A facile synthesis of. delta. -aminolevulinic acid (ALA) regio-selectively labeled with sup 13 C and direct observation of enzymatic transformation from ALA to porphobilinogen (PBG)

    Energy Technology Data Exchange (ETDEWEB)

    Kurumaya, Katsuyuki; Okazaki, Takeo; Seido, Nobuo; Akasaka, Yuzuru; Kawajiri, Yoshiki; Kajiwara, Masahiro (Meiji College of Pharmacy, Tokyo (Japan)); Kondo, Masao (Institute of Public Health, Tokyo (Japan))

    1989-02-01

    {delta}-Aminolevulinic acid (ALA), labeled with {sup 13}C at position 1, 2, 3, 4, or 5, was synthesized from {sup 13}C-labeled glycine, Meldrum's acid, or bromoacetate. The latter compounds were prepared from {sup 13}C-sodium acetate or {sup 13}C-acetic acid. Enzymatic transformation from ALA to porphobilinogen (PBG) was directly observed by {sup 13}C-NMR. (author).

  14. Omega-3 fatty acid monotherapy for pediatric bipolar disorder: a prospective open-label trial.

    Science.gov (United States)

    Wozniak, Janet; Biederman, Joseph; Mick, Eric; Waxmonsky, James; Hantsoo, Liisa; Best, Catherine; Cluette-Brown, Joanne E; Laposata, Michael

    2007-01-01

    To test the effectiveness and safety of omega-3 fatty acids (Omegabrite(R) brand) in the treatment of pediatric bipolar disorder (BPD). Subjects (N=20) were outpatients of both sexes, 6 to 17 years of age, with a DSM-IV diagnosis of BPD and Young Mania Rating Scale (YMRS) score of >15 treated over an 8-week period in open-label trial with omega-3 fatty acids 1290 mg-4300 mg combined EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). Subjects experienced a statistically significant but modest 8.9+/-2.9 point reduction in the YMRS scores (baseline YMRS=28.9+/-10.1; endpoint YMRS=19.1+/-2.6, pDHA increased in treated subjects. As only 35% of these subjects had a response by the usual accepted criteria of >50% decrease on the YMRS, omega-3 fatty acids treatment was associated with a very modest improvement in manic symptoms in children with BPD.

  15. Labelling of castor oil for myocardial studies

    International Nuclear Information System (INIS)

    Hallaba, E.; Al-Suhybani, A.; Zaki, F.S.; Abdullah, M.E.

    1985-01-01

    The labelling of castor oil, hydrolysed castor oil and oleic acid was investigated by the iodine monochloride and chloramine-T methods. The effect of the iodinating agent and the concentration of castor oil on the labelling yield was studied. A comparative pharmacological study with analog aliphatic fatty acids was carried out. Castor oil labelled with iodine monochloride concentrated in the heart and liver in good proportion, better than other natural fatty acids and nearly equal to analog aliphatic fatty acids. An infra-red study showed that the OH group of the ricinoleic acid apparently protects the 125 I added on the double bond, with minor changes in biochemical properties and better uptake by the heart muscle. (author)

  16. Labeling of ursodeoxycholic acid with technetium-99m for hepatobiliary imaging

    International Nuclear Information System (INIS)

    Sanad, M.H.; El-Tawoosy, M.

    2013-01-01

    An adopted method for the preparation of high radiochemical purity 99m Tc-ursodeoxycholic acid (UDCA) was conducted with a high radiochemical yield up to 97.5 %. The reaction proceeds well using 2 mg UDCA, 50 μg tin chloride in solution of pH 8 at room temperature for 30 min. The radiochemical yield was up to 97.5 % as pure as 99m Tc-UDCA. Different chromatographic techniques (paper chromatography and electrophoresis) were used to evaluate the radiochemical yield and purity of the labeled product. Biodistribution studies were carried out in Albino Swiss mice at different time intervals after administration of 99m Tc-UDCA. The uptake of 99m Tc-UDCA in the liver gave the chance to diagnose it. The results indicate that the labeled compound cleared from the systematic circulation within 2 h after administration and majority of organs showed significant decrease in uptake of 99m Tc-UDCA. Finally, the liver uptake was high and the results indicate the possibility of using 99m Tc-UDCA for hepatobiliary imaging.

  17. LIQUID-CHROMATOGRAPHIC ANALYSIS OF CARBOXYLIC-ACIDS USING N-(4-AMINOBUTYL)-N-ETHYLISOLUMINOL AS CHEMILUMINESCENT LABEL - DETERMINATION OF IBUPROFEN IN SALIVA

    NARCIS (Netherlands)

    STEIJGER, OM; LINGEMAN, H; BRINKMAN, UAT; HOLTHUIS, JJM; SMILDE, AK; DOORNBOS, DA

    1993-01-01

    N-(4-Aminobutyl)-N-ethylisoluminol was used for labelling of carboxylic acids. The derivatization reaction was carried out with 1-hydroxybenzotriazole as pre-activator of the carboxylic acid function and N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide as the coupling reagent. Optimum conditions for

  18. Liquid chromatographic analysis of carboxylic acids using N-(4-aminobutyl)-N-ethylisoluminol as chemiluminescent label: determination of ibuprofen in saliva

    NARCIS (Netherlands)

    Steijger, O. M.; Lingeman, H.; Brinkman, U. A.; Holthuis, J. J.; Smilde, A. K.; Doornbos, D. A.

    1993-01-01

    N-(4-Aminobutyl)-N-ethylisoluminol was used for labelling of carboxylic acids. The derivatization reaction was carried out with 1-hydroxybenzotriazole as pre-activator of the carboxylic acid function and N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide as the coupling reagent. Optimum conditions for

  19. Identification of miRNA targets with stable isotope labeling by amino acids in cell culture

    DEFF Research Database (Denmark)

    Vinther, Jeppe; Hedegaard, Mads Marquardt; Gardner, Paul Phillip

    2006-01-01

    miRNAs are small noncoding RNAs that regulate gene expression. We have used stable isotope labeling by amino acids in cell culture (SILAC) to investigate the effect of miRNA-1 on the HeLa cell proteome. Expression of 12 out of 504 investigated proteins was repressed by miRNA-1 transfection...

  20. Stable isotope labeling, in vivo, of D- and L-tryptophan pools in lemna gibba and the low incorporation of label into indole-3-acetic acid

    International Nuclear Information System (INIS)

    Baldi, B.G.; Maher, B.R.; Slovin, J.P.; Cohen, J.D.

    1991-01-01

    The authors present evidence that the role of tryptophan and other potential intermediates in the pathways that could lead to indole derivatives needs to be reexamined. Two lines of Lemna gibba were tested for uptake of [ 15 N-indole]-labeled tryptophan isomers and incorporation of that label into free indole-3-acetic acid (IAA). Both lines required levels of L-[ 15 N]tryptophan 2 to 3 orders of magnitude over endogenous levels in order to obtain measurable incorporation of label into IAA. Labeled L-tryptophan was extractable from plant tissue after feeding and showed no measurable isomerization into D-tryptophan. D-[ 15 N]trytophan supplied to Lemna at rates of approximately 400 times excess of endogenous D-tryptophan levels (to yield an isotopic enrichment equal to that which allowed detection of the incorporation of L-tryptophan into IAA), did not result in measurable incorporation of label into free IAA. These results demonstrate that L-tryptophan is a more direct precursor to IAA than the D isomer and suggest (a) that the availability of tryptophan in vivo is not a limiting factor in the biosynthesis of IAA, thus implying that other regulatory mechanisms are in operation and (b) that L-tryptophan also may not be a primary precursor to IAA in plants

  1. Arterial spin-labelling perfusion MRI and outcome in neonates with hypoxic-ischemic encephalopathy

    Energy Technology Data Exchange (ETDEWEB)

    Vis, Jill B. de; Hendrikse, Jeroen [University Medical Center Utrecht, Department of Radiology, HP E 01.132, P.O. Box 85500, Utrecht (Netherlands); Petersen, Esben T. [University Medical Center Utrecht, Department of Radiology, HP E 01.132, P.O. Box 85500, Utrecht (Netherlands); University Medical Center Utrecht, Department of Radiotherapy, Utrecht (Netherlands); Vries, Linda S. de; Bel, Frank van; Alderliesten, Thomas; Negro, Simona; Groenendaal, Floris; Benders, Manon J.N.L. [Wilhelmina Children' s Hospital/University Medical Center Utrecht, Department of Neonatology, Utrecht (Netherlands)

    2015-01-15

    Hyperperfusion may be related to outcome in neonates with hypoxic-ischemic encephalopathy (HIE). The purpose of this study was to evaluate whether arterial spin labelling (ASL) perfusion is associated with outcome in neonates with HIE and to compare the predictive value of ASL MRI to known MRI predictive markers. Twenty-eight neonates diagnosed with HIE and assessed with MR imaging (conventional MRI, diffusion-weighted MRI, MR spectroscopy [MRS], and ASL MRI) were included. Perfusion in the basal ganglia and thalami was measured. Outcome at 9 or 18 months of age was scored as either adverse (death or cerebral palsy) or favourable. The median (range) perfusion in the basal ganglia and thalami (BGT) was 63 (28-108) ml/100 g/min in the neonates with adverse outcome and 28 (12-51) ml/100 g/min in the infants with favourable outcome (p < 0.01). The area-under-the-curve was 0.92 for ASL MRI, 0.97 for MRI score, 0.96 for Lac/NAA and 0.92 for ADC in the BGT. The combination of Lac/NAA and ASL MRI results was the best predictor of outcome (r {sup 2} = 0.86, p < 0.001). Higher ASL perfusion values in neonates with HIE are associated with a worse neurodevelopmental outcome. A combination of the MRS and ASL MRI information is the best predictor of outcome. (orig.)

  2. A fast analysis method for non-invasive imaging of blood flow in individual cerebral arteries using vessel-encoded arterial spin labelling angiography

    Science.gov (United States)

    Chappell, Michael A.; Okell, Thomas W.; Payne, Stephen J.; Jezzard, Peter; Woolrich, Mark W.

    2012-01-01

    Arterial spin labelling (ASL) MRI offers a non-invasive means to create blood-borne contrast in vivo for dynamic angiographic imaging. By spatial modulation of the ASL process it is possible to uniquely label individual arteries over a series of measurements, allowing each to be separately identified in the resulting angiographic images. This separation requires appropriate analysis for which a general Bayesian framework has previously been proposed. Here this framework is adapted for clinical dynamic angiographic imaging. This specifically addresses the issues of computational speed of the algorithm and the robustness required to deal with real patient data. An algorithm is proposed that can incorporate planning information about the arteries being imaged whilst adapting for subsequent patient movement. A fast maximum a posteriori solution is adopted and shown to be only marginally less accurate than Monte Carlo sampling under simulation. The final algorithm is demonstrated on in vivo data with analysis on a time scale of the order of 10 min, from both a healthy control and a patient with a vertebro-basilar occlusion. PMID:22322066

  3. The simultaneous biosynthesis and uptake of amino acids by Lactococcus lactis studied by C-13-labeling experiments

    DEFF Research Database (Denmark)

    Jensen, N.B.S.; Christensen, B.; Nielsen, Jette

    2002-01-01

    Uniformly C-13 labeled glucose was fed to a lactic acid bacterium growing on a defined medium supplemented with all proteinogenic amino acids except glutamate. Aspartate stemming from the protein pool and from the extracellular medium was enriched with C-13 disclosing a substantial de novo...... biosynthesis of this amino acid simultaneous to its uptake from the growth medium and a rapid exchange flux of aspartate over the cellular membrane. Phenylalanine, alanine, and threonine were also synthesized de novo in spite of their presence in the growth medium....

  4. Studies on fertilizing process of multi-maleparents of poplar using 3H-labelled nucleic acids

    International Nuclear Information System (INIS)

    Han Yifan; Du Shengming; Pang Guangchang

    1986-01-01

    P. Poplar is a hybrib by crossing P. simonii with P. pyramisaliz and Salix matsudana. The hybrid is highly toleant to infertile and soil. In this experiment the second male parent (Salix matsudana) was labelled by 3 H-thymidine and 3 H-adenosine to study its function in fertilization process. The results showed the nucleic acid of Salix matsudana has entered into the fertilized embryo sac, as shown by the silver spots on the radiogaraphs of paraffin section from embryo sac 5-8 days after pollination. The radiation intensity of the hybrid seeds of Salix matsudana labelled with 3 H-A+ 3 H-T as male parent was about two times higher than that of the background and also higher than that of the controls. The more important character was that the trunk color and the winter-bud of P. poplar were similar to those of Salix matsutana. In conclusion, not only the nucleic acids of Salix matsudana entered into the fertilized egg, but also some characters of salix matsudana in the hybrid

  5. Specific labeling of the thyroxine binding site in thyroxine-binding globulin: determination of the amino acid composition of a labeled peptide fragment isolated from a proteolytic digest of the derivatized protein.

    Science.gov (United States)

    Tabachnick, M; Perret, V

    1987-08-01

    [125I] Thyroxine has been covalently bound to the thyroxine binding site in thyroxine-binding globulin by reaction with the bifunctional reagent, 1,5-difluoro-2,4-dinitrobenzene. An average of 0.47 mol of [125I] thyroxine was incorporated per mol protein; nonspecific binding amounted to 8%. A labeled peptide fragment was isolated from a proteolytic digest of the derivatized protein by HPLC and its amino acid composition was determined. Comparison with the amino acid sequence of thyroxine-binding globulin indicated partial correspondence of the labeled peptide with two possible regions in the protein. These regions also coincide with part of the barrel structure present in the closely homologous protein, alpha 1-antitrypsin.

  6. ASAP (Automatic Software for ASL Processing): A toolbox for processing Arterial Spin Labeling images.

    Science.gov (United States)

    Mato Abad, Virginia; García-Polo, Pablo; O'Daly, Owen; Hernández-Tamames, Juan Antonio; Zelaya, Fernando

    2016-04-01

    The method of Arterial Spin Labeling (ASL) has experienced a significant rise in its application to functional imaging, since it is the only technique capable of measuring blood perfusion in a truly non-invasive manner. Currently, there are no commercial packages for processing ASL data and there is no recognized standard for normalizing ASL data to a common frame of reference. This work describes a new Automated Software for ASL Processing (ASAP) that can automatically process several ASL datasets. ASAP includes functions for all stages of image pre-processing: quantification, skull-stripping, co-registration, partial volume correction and normalization. To assess the applicability and validity of the toolbox, this work shows its application in the study of hypoperfusion in a sample of healthy subjects at risk of progressing to Alzheimer's disease. ASAP requires limited user intervention, minimizing the possibility of random and systematic errors, and produces cerebral blood flow maps that are ready for statistical group analysis. The software is easy to operate and results in excellent quality of spatial normalization. The results found in this evaluation study are consistent with previous studies that find decreased perfusion in Alzheimer's patients in similar regions and demonstrate the applicability of ASAP. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Perturbation of nuclear spin polarizations in solid state NMR of nitroxide-doped samples by magic-angle spinning without microwaves

    Energy Technology Data Exchange (ETDEWEB)

    Thurber, Kent R., E-mail: thurberk@niddk.nih.gov; Tycko, Robert [Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520 (United States)

    2014-05-14

    We report solid state {sup 13}C and {sup 1}H nuclear magnetic resonance (NMR) experiments with magic-angle spinning (MAS) on frozen solutions containing nitroxide-based paramagnetic dopants that indicate significant perturbations of nuclear spin polarizations without microwave irradiation. At temperatures near 25 K, {sup 1}H and cross-polarized {sup 13}C NMR signals from {sup 15}N,{sup 13}C-labeled L-alanine in trinitroxide-doped glycerol/water are reduced by factors as large as six compared to signals from samples without nitroxide doping. Without MAS or at temperatures near 100 K, differences between signals with and without nitroxide doping are much smaller. We attribute most of the reduction of NMR signals under MAS near 25 K to nuclear spin depolarization through the cross-effect dynamic nuclear polarization mechanism, in which three-spin flips drive nuclear polarizations toward equilibrium with spin polarization differences between electron pairs. When T{sub 1e} is sufficiently long relative to the MAS rotation period, the distribution of electron spin polarization across the nitroxide electron paramagnetic resonance lineshape can be very different from the corresponding distribution in a static sample at thermal equilibrium, leading to the observed effects. We describe three-spin and 3000-spin calculations that qualitatively reproduce the experimental observations.

  8. Perturbation of nuclear spin polarizations in solid state NMR of nitroxide-doped samples by magic-angle spinning without microwaves

    International Nuclear Information System (INIS)

    Thurber, Kent R.; Tycko, Robert

    2014-01-01

    We report solid state 13 C and 1 H nuclear magnetic resonance (NMR) experiments with magic-angle spinning (MAS) on frozen solutions containing nitroxide-based paramagnetic dopants that indicate significant perturbations of nuclear spin polarizations without microwave irradiation. At temperatures near 25 K, 1 H and cross-polarized 13 C NMR signals from 15 N, 13 C-labeled L-alanine in trinitroxide-doped glycerol/water are reduced by factors as large as six compared to signals from samples without nitroxide doping. Without MAS or at temperatures near 100 K, differences between signals with and without nitroxide doping are much smaller. We attribute most of the reduction of NMR signals under MAS near 25 K to nuclear spin depolarization through the cross-effect dynamic nuclear polarization mechanism, in which three-spin flips drive nuclear polarizations toward equilibrium with spin polarization differences between electron pairs. When T 1e is sufficiently long relative to the MAS rotation period, the distribution of electron spin polarization across the nitroxide electron paramagnetic resonance lineshape can be very different from the corresponding distribution in a static sample at thermal equilibrium, leading to the observed effects. We describe three-spin and 3000-spin calculations that qualitatively reproduce the experimental observations

  9. Perturbation of nuclear spin polarizations in solid state NMR of nitroxide-doped samples by magic-angle spinning without microwaves.

    Science.gov (United States)

    Thurber, Kent R; Tycko, Robert

    2014-05-14

    We report solid state (13)C and (1)H nuclear magnetic resonance (NMR) experiments with magic-angle spinning (MAS) on frozen solutions containing nitroxide-based paramagnetic dopants that indicate significant perturbations of nuclear spin polarizations without microwave irradiation. At temperatures near 25 K, (1)H and cross-polarized (13)C NMR signals from (15)N,(13)C-labeled L-alanine in trinitroxide-doped glycerol/water are reduced by factors as large as six compared to signals from samples without nitroxide doping. Without MAS or at temperatures near 100 K, differences between signals with and without nitroxide doping are much smaller. We attribute most of the reduction of NMR signals under MAS near 25 K to nuclear spin depolarization through the cross-effect dynamic nuclear polarization mechanism, in which three-spin flips drive nuclear polarizations toward equilibrium with spin polarization differences between electron pairs. When T1e is sufficiently long relative to the MAS rotation period, the distribution of electron spin polarization across the nitroxide electron paramagnetic resonance lineshape can be very different from the corresponding distribution in a static sample at thermal equilibrium, leading to the observed effects. We describe three-spin and 3000-spin calculations that qualitatively reproduce the experimental observations.

  10. Bioavailability of zinc to rats from defatted soy flour, acid-precipitated soy concentrate and neutralized soy concentrate as determined by intrinsic and extrinsic labeling techniques

    International Nuclear Information System (INIS)

    Ketelsen, S.M.; Stuart, M.A.; Weaver, C.M.; Forbes, R.M.; Erdman, J.W. Jr.

    1984-01-01

    The bioavailability of 65Zn from intrinsically and extrinsically labeled soy flour, acid-precipitated soy concentrate and neutralized soy concentrate was evaluated in rats. Weanling rats were fed marginally zinc-deficient diets, providing 8 ppm zinc from one of these three soy products, for 7 days. The rats then received a radioactively labeled test meal, identical in composition to the previous diet except that the soy product was either intrinsically or extrinsically labeled with 65Zn. After the test meal the rats were again fed diets the same as those consumed prior to the test meal. Whole-body retention of 65Zn at 24 hours and 12 days as well as 65Zn retained in tibias of rats given meals containing neutralized concentrate-based meals was significantly lower than for rats given meals containing the soy flour or acid-precipitated concentrate. In addition, retention of 65Zn from the extrinsically labeled acid-precipitated concentrate-based meal was significantly higher than from the same product intrinsically labeled. These findings confirm the results of previous feeding studies from which it was suggested that neutralization of soy protein concentrates reduces zinc bioavailability to the rat. In addition, the results are taken to suggest that experimental conditions may influence the validity of the extrinsic labeling technique for zinc

  11. Skull metastases detecting on arterial spin labeling perfusion: Three case reports and review of literature.

    Science.gov (United States)

    Ryu, Kyeong H; Baek, Hye J; Cho, Soo B; Moon, Jin I; Choi, Bo H; Park, Sung E; An, Hyo J

    2017-11-01

    Detection of skull metastases is as important as detection of brain metastases because early diagnosis of skull metastases is a crucial determinant of treatment. However, the skull can be a blind spot for assessing metastases on routine brain magnetic resonance imaging (MRI). To the best of our knowledge, the finding of skull metastases on arterial spin labeling (ASL) has not been reported. ASL is a specific MRI sequence for evaluating cerebral blood flow using magnetized endogenous inflow blood. This study uses ASL as a routine sequence of brain MRI protocol and describes 3 clinical cases of skull metastases identified by ASL. The study also highlights the clinical usefulness of ASL in detecting skull metastases. Three patients with known malignancy underwent brain MRI to evaluate for brain metastases. All of the skull metastases were conspicuously depicted on routine ASL images, and the lesions correlated well with other MRI sequences. Three patients received palliative chemotherapy. Three patients are being followed up regularly at the outpatient department. The routine use of ASL may help to detect lesions in blind spots, such as skull metastases, and to facilitate the evaluation of intracranial pathologies without the use of contrast materials in exceptional situations.

  12. Cerebral blood flow measured by arterial spin labeling MRI at resting state in normal aging and Alzheimer's disease.

    Science.gov (United States)

    Zhang, Nan; Gordon, Marc L; Goldberg, Terry E

    2017-01-01

    Arterial spin labeling (ASL) magnetic resonance imaging uses arterial blood water as an endogenous tracer to measure cerebral blood flow (CBF). In this review, based on ASL studies in the resting state, we discuss state-of-the-art technical and data processing improvements in ASL, and ASL CBF changes in normal aging, mild cognitive impairment (MCI), Alzheimer's disease (AD), and other types of dementia. We propose that vascular and AD risk factors should be considered when evaluating CBF changes in aging, and that other validated biomarkers should be used as inclusion criteria or covariates when evaluating CBF changes in MCI and AD. With improvements in hardware and experimental design, ASL is proving to be an increasingly promising tool for exploring pathogenetic mechanisms, early detection, monitoring disease progression and pharmacological response, and differential diagnosis of AD. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  13. Influence of the glutamic acid content of the diet on the catabolic rate of labelled glutamic acid in rats. 2

    International Nuclear Information System (INIS)

    Wilke, A.; Simon, O.; Bergner, H.

    1984-01-01

    40 rats with a body weight of 100 g received 7 semisynthetic diets with different contents of glutamic acid and one diet contained whole-egg. A L-amino acid mixture corresponding to the pattern of egg protein was the protein source of the semisynthetic diets. Glutamic acid was supplemented succesively from 0 to 58 mol-% of the total amino acid content. On the 8th day of the experimental feeding the animals were labelled by subcutaneous injection of 14 C-glutamic acid. Subsequently the CO 2 and the 14 CO 2 excretion were measured for 24 hours. In this period 64 to 68 % of the injected radioactivity were recovered as 14 CO 2 . The curve pattern of 14 CO 2 excretion indicates two different processes of 14 CO 2 formation. One characterizing the direct degradation of glutamic acid to CO 2 with a high rate constant and a second one with a lower rate constant characterizing the 14 CO 2 formation via metabolites of glutamic acid. 77 % of the total 14 CO 2 excretion in 24 hours resulted from the direct oxidation of glutamic acid and 23 % from the oxidation of intermediates. When 14 CO 2 formation was measured 10 to 24 hours after injection of 14 C-glutamic acid a positive correlation to the content of glutamic acid in the diet was observed. The intestinal tissue contributes considerably to the catabolization of glutamic acid, however, there seems to exist an upper limit for this capacity. (author)

  14. Advances in stable isotope assisted labeling strategies with information science.

    Science.gov (United States)

    Kigawa, Takanori

    2017-08-15

    Stable-isotope (SI) labeling of proteins is an essential technique to investigate their structures, interactions or dynamics by nuclear magnetic resonance (NMR) spectroscopy. The assignment of the main-chain signals, which is the fundamental first step in these analyses, is usually achieved by a sequential assignment method based on triple resonance experiments. Independently of the triple resonance experiment-based sequential assignment, amino acid-selective SI labeling is beneficial for discriminating the amino acid type of each signal; therefore, it is especially useful for the signal assignment of difficult targets. Various combinatorial selective labeling schemes have been developed as more sophisticated labeling strategies. In these strategies, amino acids are represented by combinations of SI labeled samples, rather than simply assigning one amino acid to one SI labeled sample as in the case of conventional amino acid-selective labeling. These strategies have proven to be useful for NMR analyses of difficult proteins, such as those in large complex systems, in living cells, attached or integrated into membranes, or with poor solubility. In this review, recent advances in stable isotope assisted labeling strategies will be discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Investigation of the biosynthesis of acetyl-CoA and oxaloacetic acid from pyruvic acid and the quantitative evaluation of incorporated 13C-labeled l-alanine in Arthrobacter hyalinus

    International Nuclear Information System (INIS)

    Katsumi Iida

    2014-01-01

    Studies on the contribution to acetyl-CoA and oxaloacetic acid from the pyruvic acid transformation from l-alanine in Arthrobacter hyalinus were conducted by means of feeding experiments with l-[1- 13 C]alanine and l-[3- 13 C]alanine, followed by an analysis of the labeling patterns of coproporphyrinogen III using 13 C NMR spectroscopy. The results demonstrated that l-alanine was transformed via pyruvic acid to both acetyl-CoA and oxaloacetic acid. Additionally, the quantitative analysis indicated that pyruvic acid was transformed to acetyl-CoA and oxaloacetic acid in the ratio of 1:0.8. (author)

  16. Selenium as an alternative peptide label - comparison to fluorophore-labelled penetratin

    DEFF Research Database (Denmark)

    Hyrup Møller, Laura; Bahnsen, Jesper Søborg; Nielsen, Hanne Mørck

    2015-01-01

    lysates, primarily the intact peptide (PenMSe, TAMRA-PenMSe or TAMRA-Pen) was observed. Selenium labelling caused minimal alteration of the physicochemical properties of the peptide and allowed for absolute quantitative determination of cellular uptake by inductively coupled plasma mass spectrometry......In the present study, the impact on peptide properties of labelling peptides with the fluorophore TAMRA or the selenium (Se) containing amino acid SeMet was evaluated. Three differently labelled variants of the cell-penetrating peptide (CPP) penetratin (Pen) were synthesized, PenMSe, TAMRA....... Selenium is thus proposed as a promising alternative label for quantification of peptides in general, altering the properties of the peptide to a minor extent as compared to commonly used peptide labels....

  17. Bimodal Porous Scaffolds by Sequential Electro spinning of Poly(glycolic acid) with Sucrose Particles

    International Nuclear Information System (INIS)

    Wulkersdorfer, B.; Kao, K.K.; Agopian, V.G.; Ahn, A.; Dunn, J.C.; Wu, B.M.; Stelzner, M.; Kao, K.K.; Agopian, K.J.; Dunn, J.C.; Wu, B.M.; Stelzner, M.; Dunn, J.C.; Wu, B.M.

    2009-01-01

    Electro spinning is a method to produce fine, bio polymer mesh with a three-dimensional architecture that mimics native extra-cellular matrix. Due to the small fiber diameter created in this process, conventional electro spun scaffolds have pore sizes smaller than the diameter of most cells. These scaffolds have limited application in tissue engineering due to poor cell penetration. We developed a hybrid electro spinning/particulate leaching technique to create scaffolds with increased porosity and improved cellular ingrowth. Poly(glycolic acid) (PGA) and a sucrose-ethanol suspension were electro spun in equal, alternating sequences at intervals of one, two, and ten minutes each. The scaffolds revealed fiber mesh with micropores of 10 μm and uniformly distributed sucrose particles. Particulate leaching of sucrose from the one- or two-minute scaffolds revealed honeycomb structures with interconnected macro pores between 50 and 250 μm. Sucrose leaching from the ten-minute scaffolds resulted in laminated structures with isolated macro pores between 200 and 350 μm. Macro pore size was directly proportional to the duration of the sucrose spinning interval. After 24 hours of cell culture, conventionally spun scaffolds demonstrated no cellular penetration. Conversely, the PGA/sucrose scaffolds demonstrated deep cellular penetration. This hybrid technique represents a novel method of generating electro spun scaffolds with interconnected pores suitable for cellular ingrowth.

  18. Stable isotope N-phosphoryl amino acids labeling for quantitative profiling of amine-containing metabolites using liquid chromatography mass spectrometry.

    Science.gov (United States)

    Zhang, Shanshan; Shi, Jinwen; Shan, Changkai; Huang, Chengting; Wu, Yile; Ding, Rong; Xue, Yuhua; Liu, Wen; Zhou, Qiang; Zhao, Yufen; Xu, Pengxiang; Gao, Xiang

    2017-07-25

    Stable isotope chemical labeling liquid chromatography-mass spectrometry (LC-MS) is a powerful strategy for comprehensive metabolomics profiling, which can improve metabolites coverage and quantitative information for exploration of metabolic regulation in complex biological systems. In the current work, a novel stable isotope N-phosphoryl amino acids labeling strategy (SIPAL) has been successful developed for quantitative profiling of amine-containing metabolites in urine based on organic phosphorus chemistry. Two isotopic reagents, 16 O 2 - and 18 O 2 -N-diisopropyl phosphoryl l-alanine N-hydroxysuccinimide esters ( 16 O/ 18 O-DIPP-L-Ala-NHS), were firstly synthesized in high yields for labeling the amine-containing metabolites. The performance of SIPAL strategy was tested by analyzing standard samples including 20 l-amino acids, 10 d-amino acids and small peptides by using LC-MS. We observed highly efficient and selective labeling for SIPAL strategy within 15 min in a one-pot derivatization reaction under aqueous reaction conditions. The introduction of a neutral phosphate group at N-terminus can increase the proton affinity and overall hydrophobicity of targeted metabolites, leading to the better ionization efficiency in electrospray ionization processes and chromatographic separations of hydrophilic metabolites on reversed-phase column. Furthermore, the chiral metabolites, such as d-amino acids, could be converted to diastereomers after SIPAL and successfully separated on regular reversed-phase column. The chirality of labeled enantiomers can be determined by using different detection methods such as 31 P NMR, UV, and MS, demonstrating the potential application of SIPAL strategy. In addition, absolute quantification of chiral metabolites in biological samples can be easily achieved by using SIPAL strategy. For this purpose, urine samples collected from a healthy volunteer were analyzed by using LC-ESI-Orbitrap MS. Over 300 pairs of different amine

  19. Myocardial distribution of I131-labeled hexadecenoic acid in relation to the dog local coronary flow

    International Nuclear Information System (INIS)

    Riche, F.; Busquet, G.; Pilichowski, P.; Wolf, J.E.; Mathieu, J.P.; Comet, M.; Pernin, C.; Vidal, M.; Vincens, M.; Godart, J.

    1981-01-01

    20 anesthetized and thoracotomized dogs are studied. The local myocardial blood flow is measured with sup(99m)Tc human albumin microspheres. The intramyocardial distribution of the 16-I(131)-9-hexadecenoic acid in relation to local blood flow is studied in basal conditions (7 dogs), after experimental infarction (6 dogs) and postischemic reactive hyperhemia (7 dogs). We conclude that during basal condition, after infarction but not during reactive hyperhemia, the distribution of the labeled fatty acid reflect the local variations of blood flow [fr

  20. Effect of polysaccharide capsule of the microalgae Staurastrum iversenii var. americanum on diffusion of charged and uncharged molecules, using EPR technique

    International Nuclear Information System (INIS)

    Freire-Nordi, Cristina S.; Nascimento, Otaciro R.; Vieira, Armando A.H.; Nakaie, Clovis R.

    2006-01-01

    The existence of a mucilaginous envelope, sheath or capsule is usual in many desmids, but few data concerning its function are available. Previous studies of the transport function and permeation of molecules through the algae capsules were done using the algae Spondylosium panduriforme and Nephrocytium lunatum, the Electron Paramagnetic Resonance (EPR) technique, and different spin labels. The results suggested that the capsule functions as a selective diffusion medium. In the present work charged and uncharged molecules (spin labels group A) and Staurastrum iversenii var. americanum (Desmids),whose alga presents a great mucilaginous capsule, were used. Charged nitroxide molecules similar to amino acids (spin labels group B) were also used allowing a better understanding of the electrostatic effect in the permeation process across the capsule. The role of the cell capsule in the solute diffusion was evaluated by determining the capsulated and decapsulated cell permeation times. The permeation times for all spin labels tested in the cells lacking capsules were always shorter than those containing this physical barrier. The decay times of spin labels group A observed for S. iversenii were compared to other studied algae. The results regarding the diffusion of charged spin labels group B suggested that the interaction of cell capsule occurs more strongly with negatively charged molecules than with positively charged ones. The results obtained in this work with spin labels group A confirm that the capsule is an essential structure for the cell, and that due to the polar interactions with the spin labels, it plays an important role in the selection of small molecules. Several parameters, mainly those of electrostatic nature, seem to control the permeation across the algal capsules of spin labels group B, showing that structures which are similar to amino acids could diffuse across the interior of the algal cell. (author)

  1. Adaptation of a Commonly Used, Chemically Defined Medium for Human Embryonic Stem Cells to Stable Isotope Labeling with Amino Acids in Cell Culture

    DEFF Research Database (Denmark)

    Liberski, A. R.; Al-Noubi, M. N.; Rahman, Z. H.

    2013-01-01

    Metabolic labeling with stable isotopes is a prominent technique for comparative quantitative proteomics, and stable isotope labeling with amino acids in cell culture (SILAC) is the most commonly used approach. SILAC is, however, traditionally limited to simple tissue culture regimens and only ra...

  2. Preparation of 2H- and 3H-labeled phaseic acid and dihydrophaseic acid as standards for determination of abscisic acid metabolites in tomato fruit

    International Nuclear Information System (INIS)

    Kubik, M.; Buta, J.G.

    1990-01-01

    There have been reports that the level of abscisic acid (ABA) increases during the cold storage of tomatoes. However, the important ABA metabolites, phaseic acid (PA) and dihydrophaseic acid (DPA) were never quantitatively determined in such a system. In order to obtain the labeled standards for quantitative determination of those compounds by GC-MS-SIM, we fed bean plants with 6,6,6-[ 2 H 3 ]-ABA (mean isotopic enrichment 60%) with addition of about 10 5 Bq per mg of [ 3 H]-ABA. After 100 hours the plants were harvested and extracted with acetone. The extract were purified by solvent partitioning and, Prep-Sep amino column and on an HPLC C 18 reverse phase column. Two major radioactive metabolites of ABA were obtained and identified by GC-MS as PA and DPA. Some results on the quantitation of ABA, PA and DPA in tomato fruit after cold storage will be presented

  3. Saturated and trans fatty acids content in unpackaged traditional bakery products in Santa Fe city, Argentina: nutrition labeling relevance.

    Science.gov (United States)

    Negro, Emilse; González, Marcela Aída; Bernal, Claudio Adrián; Williner, María Rosa

    2017-08-01

    Studies have reported the relationship between the excessive intake of saturated fatty acids (SFA) and trans fatty acids (t-FA) and an increased risk of cardiovascular disease. Since 2006, the MERCOSUR countries require that the mandatory nutrition labeling should include information not only about the content of SFA but also about the content of t-FA. This does not apply to fractionated products at the point of retail, such as bakery products. This paper aimed to determine the total fat content and the fatty acid profile in unpackaged traditional bakery products (breads, biscuits and pastries) in Santa Fe, Argentina. Except for French bread, the contribution of t-FA and SFA to the total FA consumption from baked products was high. On the other hand, due to the high variability detected in the FA composition of bakery products between bakeries, it would be necessary to implement regulations making nutrition labeling mandatory in these products.

  4. Synthesis of labeled compounds

    International Nuclear Information System (INIS)

    Whaley, T.W.

    1977-01-01

    Intermediate compounds labeled with 13 C included methane, sodium cyanide, methanol, ethanol, and acetonitrile. A new method for synthesizing 15 N-labeled 4-ethylsulfonyl-1-naphthalene-sulfonamide was developed. Studies were conducted on pathways to oleic-1- 13 C acid and a second pathway investigated was based on carbonation of 8-heptadecynylmagnesium bromide with CO 2 to prepare sterolic acid. Biosynthetic preparations included glucose- 13 C from starch isolated from tobacco leaves following photosynthetic incubation with 13 CO 2 and galactose- 13 C from galactosylglycerol- 13 C from kelp. Research on growth of organisms emphasized photosynthetic growth of algae in which all cellular carbon is labeled. Preliminary experiments were performed to optimize the growth of Escherichia coli on sodium acetate- 13 C

  5. Synthesis of the mevalonic acid labelled with "1"4C, "1"3C and "3H

    International Nuclear Information System (INIS)

    Rousseau, Bernard

    1982-01-01

    This thesis describes five new methods of synthesis of the (R,S) mevalonic acid adapted to the labelling with "1"4C and "1"3C in positions 4,5 or 5 or 3', or with tritium in position 3'. Three of them use the tri-oxa-2,4,10 adamantyl group as masked carboxyl function. The two others take benefit from the regioselectivity of the bis-hydro-boration of terminal acetylenics by the 9-borabicyclo [3-3-1]nonane. The acylation of the bis-trimethylsilyl lithiomalonate, and the chemistry of dithiannes are also involved. Acetylene and methyl iodide labelled with isotopes are used as cheap base products [fr

  6. Process for the impromptu preparation of a radio-iodine-labelled injectable fatty acid and the preparation of iodinated derivatives suitable for the application of this process

    International Nuclear Information System (INIS)

    Bardy, Andre; Comet, Michel; Coornaert, Sabine; Mathieu, J.P.; Riche, Francoise; Vidal, Michel.

    1983-01-01

    The radioiodine-labelled fatty acid is prepared by reaction of a fatty acid, bromated or iodinated in the #betta# position, with an aqueous solution of radioactive iodide at pH 7 in the presence of carrier iodide. The labelled product obtained is suspended in a buffer solution at pH 9 then dissolved in human serum albumin for injection purposes. The iodinated derivatives used as starting products may be obtained by condensation of a bromated fatty acid and an acetylene alcohol [fr

  7. Selective retrograde labeling of lateral olivocochlear neurons in the brainstem based on preferential uptake of 3H-D-aspartic acid in the cochlea

    International Nuclear Information System (INIS)

    Ryan, A.F.; Schwartz, I.R.; Helfert, R.H.; Keithley, E.; Wang, Z.X.

    1987-01-01

    We have previously shown that perfusion of the gerbil cochlea with probe concentrations of 3 H-D-aspartic acid (D-ASP) results in immediate, selective labeling of 50-60% of the efferent terminals under the inner hair cells, presumably by high-affinity uptake. The present study was undertaken to determine the origin of these endings. Twenty-four hours after cochlear perfusion with D-ASP, labeled neurons were observed in the ipsilateral, and to a much lesser extent in the contralateral, lateral superior olivary nucleus (LSO). The cells were small, primarily fusiform, and showed fewer synaptic contacts than other LSO cells. Combined transport of D-ASP and horseradish peroxidase indicated that all olivocochlear neurons within the LSO that projected to the injected cochlea were labeled by D-ASP. Labeled fibers coursed dorsally from the LSO, joined contralateral fibers that had passed under the floor of the fourth ventricle, and entered the VIIIth nerve root at its ventromedial edge. Adjacent to the ventral cochlear nucleus (VCN), densely labeled collateral fibers crossed the nerve root to enter the VCN. Labeled fibers and terminals were prominent in the central VCN. Neither retrograde transport of D-ASP by medial olivocochlear and vestibular efferents nor anterograde transport by VIIIth nerve afferents was observed. The D-ASP-labeled cells and fibers are clearly lateral olivocochlear efferents. Retrograde transport of D-ASP thus allows the cells, axons, and collaterals of the lateral olivocochlear system to be studied, morphologically, in isolation from other cells that project to the cochlea. Since the olivocochlear neurons are almost certainly cholinergic, retrograde amino acid transport does not necessarily identify the primary neurotransmitter of a neuron. Rather, it indicates the presence of selective uptake by the processes of that neuron at the site of amino acid injection

  8. The perils of pathogen discovery: origin of a novel parvovirus-like hybrid genome traced to nucleic acid extraction spin columns.

    Science.gov (United States)

    Naccache, Samia N; Greninger, Alexander L; Lee, Deanna; Coffey, Lark L; Phan, Tung; Rein-Weston, Annie; Aronsohn, Andrew; Hackett, John; Delwart, Eric L; Chiu, Charles Y

    2013-11-01

    Next-generation sequencing was used for discovery and de novo assembly of a novel, highly divergent DNA virus at the interface between the Parvoviridae and Circoviridae. The virus, provisionally named parvovirus-like hybrid virus (PHV), is nearly identical by sequence to another DNA virus, NIH-CQV, previously detected in Chinese patients with seronegative (non-A-E) hepatitis. Although we initially detected PHV in a wide range of clinical samples, with all strains sharing ∼99% nucleotide and amino acid identity with each other and with NIH-CQV, the exact origin of the virus was eventually traced to contaminated silica-binding spin columns used for nucleic acid extraction. Definitive confirmation of the origin of PHV, and presumably NIH-CQV, was obtained by in-depth analyses of water eluted through contaminated spin columns. Analysis of environmental metagenome libraries detected PHV sequences in coastal marine waters of North America, suggesting that a potential association between PHV and diatoms (algae) that generate the silica matrix used in the spin columns may have resulted in inadvertent viral contamination during manufacture. The confirmation of PHV/NIH-CQV as laboratory reagent contaminants and not bona fide infectious agents of humans underscores the rigorous approach needed to establish the validity of new viral genomes discovered by next-generation sequencing.

  9. Preparation of C-II labeled pyruvic acid for use in assessment of hypoxia in tumors. Project 4

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    Of the three methods of synthesis of C-II-labeled pyruvic acid that we had proposed to investigate in order to determine the best and most appropriate synthesis of C-II-labeled pyruvate, the cold chemistry of Method A, via an isocyanide intermediate, has been verified. Similarly, the cold chemistry of Method B, via the 1,3-dithiane derivative, has been verified up to the deprotection and last step of the synthesis. The difficulties which have been encountered with the biochemistry of Method C from ribulose 1,5-diphosphate, have yet to be resolved. 12 refs., 6 figs

  10. Oxidation of formic acid by oxyanions of chlorine and its implications to the Viking Labeled Release experiment

    Science.gov (United States)

    Martinez, P.; Navarro-gonzalez, R.

    2013-05-01

    The Viking Landers that arrived on Mars in 1976 carried out three biological experiments designed to investigate if there was microbial life. These were the Gas-Exchange, Pyrolitic Release and Labeled Release experiments. The three experiments yielded positive responses but the Labeled Release experiment had a kinetic response indicative of microbial activity. The experiment consisted of adding a broth of nutrients (formic acid, glycolic acid, glycine, D- and L-alanine and D- and L-lactic acid uniformly marked with 14C) to martian soil samples. The results were surprising; the nutrients were consumed releasing radioactive gases in a manner that is compatible by terrestrial microorganisms. The existence of Martian life was contradicted by soil chemical analysis that indicated the absence of organic compounds above the detection limits of parts per billion (ppb). Instead the positive response of the Labeled Release Experiment was attributed to the existence of peroxides and/or superoxides in the Martian soils that destroyed the nutrients upon contact. Recently, the Phoenix mission that landed in the Martian Arctic in 2008 revealed the presence of a highly oxidized form of the element chlorine in the soil: perchlorate. Perchlorate is thought to have formed in the Martian atmosphere by the oxidation of chloride from volcanic sources with ozone. Therefore perchlorate is formed by the stepwise oxidation of hypochlorite, chlorite and chlorate. These oxyanions of chlorine are powerful oxidizers that may exist in the Martian soil and may have reacted with the nutrients of the Labeled Release Experiment. This paper aims to better understand these results by designing experiments to determine the kinetics of decomposition of formic acid to carbon dioxide with different oxidized forms of chlorine by headspace technique in gas chromatography coupled to mass spectrometry (GC / MS). Previous studies done in the laboratory showed that only hypochlorite quantitatively reacted with

  11. New tools for immunochemistry: internally labelled monoclonal antibodies

    International Nuclear Information System (INIS)

    Galfre, G.; Cuello, A.C.

    1981-01-01

    Labelled antibodies are routinely used in a wide variety of immunochemical methods. Over the years several labelling techniques have been developed and the discussion of some of them forms a substantial part of this course. Common to all the procedures is the need to purify the antibodies. The labelling itself consists of coupling the antibodies to a ''label'' molecule by means of a chemical reaction. Preparation in vitro of monoclonal antibodies offers the unique possibility to internally label them. Although this is restricted to radiolabelling, and the specific activity achieved is limited, the procedure is extremely simple, does not require purification prior to labelling and chemical manipulation is not necessary as the antibodies themselves are synthesized from radioactive amino acids. Moreover, different labels can be used ( 14 C, 35 S, 3 H) which have a much longer half-life than 125 I. The choice of labelled amino acid precurors and labelling procedure is discussed. The uses of internally-labelled monoclonal antibodies are indicated. (Auth.)

  12. Encapsulated specialty oils commercialized in São Paulo state, Brazil: evaluation of identity (fatty acid profile and compliance of fatty acids and Vitamin E contents with nutrition labeling

    Directory of Open Access Journals (Sweden)

    Karen Hirashima

    2013-03-01

    Full Text Available Encapsulated specialty oils commercialized in São Paulo state, Brazil, were evaluated for their identity (fatty acids profile and compliance with nutrition labeling (fatty acids and Vitamin E (alpha tocopherol contents. Twenty one samples [flaxseed oil (6, evening primrose (5, safflower (8, borage (1, and black currant (1] purchased from local markets or collected by the health surveillance agency were analyzed. The fatty acids and vitamin E contents were analyzed by gas chromatography with flame ionization detector and liquid chromatography with UV detector, respectively. Nine samples were adulterated (5 samples of safflower oil, 3 of flaxseed oil, and one of evening primrose. Among them, 3 flaxseed and 2 safflower oil samples were probably adulterated by the addition of soybean oil. Conjugated linoleic acid (CLA was found in two safflower oils samples although the sale of oils with conjugated linoleic acid (CLA is not permitted by the National Health Surveillance Agency in Brazil (ANVISA. Only two samples presented all values in compliance with nutrition labeling (one safflower oil sample and one borage oil sample. The results show that a continuous monitoring of encapsulated specialty oils commercialized in Brazil is necessary including a greater number of samples and sanitary surveillance.

  13. Resting state cerebral blood flow with arterial spin labeling MRI in developing human brains.

    Science.gov (United States)

    Liu, Feng; Duan, Yunsuo; Peterson, Bradley S; Asllani, Iris; Zelaya, Fernando; Lythgoe, David; Kangarlu, Alayar

    2018-07-01

    The development of brain circuits is coupled with changes in neurovascular coupling, which refers to the close relationship between neural activity and cerebral blood flow (CBF). Studying the characteristics of CBF during resting state in developing brain can be a complementary way to understand the functional connectivity of the developing brain. Arterial spin labeling (ASL), as a noninvasive MR technique, is particularly attractive for studying cerebral perfusion in children and even newborns. We have collected pulsed ASL data in resting state for 47 healthy subjects from young children to adolescence (aged from 6 to 20 years old). In addition to studying the developmental change of static CBF maps during resting state, we also analyzed the CBF time series to reveal the dynamic characteristics of CBF in differing age groups. We used the seed-based correlation analysis to examine the temporal relationship of CBF time series between the selected ROIs and other brain regions. We have shown the developmental patterns in both static CBF maps and dynamic characteristics of CBF. While higher CBF of default mode network (DMN) in all age groups supports that DMN is the prominent active network during the resting state, the CBF connectivity patterns of some typical resting state networks show distinct patterns of metabolic activity during the resting state in the developing brains. Copyright © 2018 European Paediatric Neurology Society. All rights reserved.

  14. Technetium and rhenium complexes with modified fatty acid ligands 4. Evaluation of two new classes of 99mTc-labelled fatty acids as potential tracers for myocardial metabolism imaging

    International Nuclear Information System (INIS)

    Heintz, A.; Kropp, J.; Deussen, A.; Jung, C.M.; Spies, H.

    2002-01-01

    99m Tc-labelled fatty acids were synthesized according to the '3+1' mixed-ligand approach and investigated as potential tracers for myocardial SPECT diagnostics on the model of the isolated guinea pig heart. The results indicate a low but specific myocardial uptake of the 99m Tc fatty acid derivatives subject to chain length and structure. (orig.)

  15. Noninvasive measurements of regional cerebral perfusion in preterm and term neonates by magnetic resonance arterial spin labeling.

    Science.gov (United States)

    Miranda, Maria J; Olofsson, Kern; Sidaros, Karam

    2006-09-01

    Magnetic resonance arterial spin labeling (ASL) at 3 Tesla has been investigated as a quantitative technique for measuring regional cerebral perfusion (RCP) in newborn infants. RCP values were measured in 49 healthy neonates: 32 preterm infants born before 34 wk of gestation and 17 term-born neonates. Examinations were performed on unsedated infants at postmenstrual age of 39-40 wk in both groups. Due to motion, reliable data were obtained from 23 preterm and 6 term infants. Perfusion in the basal ganglia (39 and 30 mL/100 g/min for preterm and term neonates, respectively) was significantly higher (p neonates at term-equivalent age and in term neonates. Perfusion was significantly higher (p = 0.01) in the preterm group than in the term infants, indicating that RCP may be influenced by developmental and postnatal ages. This study demonstrates, for the first time, that noninvasive ASL at 3T may be used to measure RCP in healthy unsedated preterm and term neonates. ASL is, therefore, a viable tool that will allow serial studies of RCP in high-risk neonates.

  16. Comparative evaluation of labelling patterns and turnover of lipids, tagged by 15 (p-123I-phenyl-)pentadecanoic and 1-14C-palmitic acid

    International Nuclear Information System (INIS)

    Reske, S.N.; Sauer, W.; Reichmann, K.; Winkler, C.; Machulla, H.J.; Knust, E.J.

    1984-01-01

    Uptake and turnover of chloroform/methanol extractable tissue lipids labelled in vivo simultaneously with 15(p- 123 I-phenyl-)pentadecanoic and 1- 14 C-palmitic acid were compared. Lipid turnover studies were performed in fasted pentobarbital-anaesthetized Wistar rats in tissues with highly varying free fatty acid turnover rates. In all tissues investigated, i.e. heart, lung, liver, spleen and kidney, both tracers labelled nearly identical lipid fractions. The main tracer uptake was found in free fatty acids, phospholipids, diglycerides and triglycerides. A highly significant correlation of uptake and turnover in main tissue lipid fractions indicated an essentially identical metabolic pathway of both tracers in intermediary tissue lipid metabolism. Concordant tracer uptake and turnover patterns in tissue of lipids with highly varying fatty acid metabolic rates suggested that intrinsic metabolic activity of the tissue and respective lipid fraction was the major determinant of metabolic handling of both iodophenyl fatty- and palmitic acid. Thus, the feasibility of iodophenylpentadecanoic acid as free fatty acid tracer for studying tissue lipid metabolism is demonstrated. (author)

  17. Potential use of carbon-11 labeled alpha-aminoisobutyric acid (AIB) as an in vivo tracer of amino acid uptake in differing metabolic states

    International Nuclear Information System (INIS)

    Conti, P.S.; Starnes, H.F.; Brennan, M.F.

    1986-01-01

    AIB has been used as a model amino acid for the evaluation of alanine-preferring amino acid transport. Hormonal factors and starvation alter the tissue distribution of amino acids, particularly in liver and muscle. With positron emission tomography and labeling of biochemical tracers with C-11, (t1/2=20.4 min), it is now possible to study amino acid kinetics in vivo using external imaging. In order to investigate the utility of C-11 AIB as an in vivo tracer of altered tissue metabolism, C-14 AIB was studied in groups of rats with either streptozotocin-induced diabetes, insulin-induced hypoglycemia or starvation. The data suggest an increased amino acid uptake in liver in starvation, an increased uptake in muscle in response to insulin and associated hypoglycemia and decreased transport in muscle in starvation, as seen by other investigators. These results suggest that C-11 AIB may be useful as an in vivo monitor of metabolic changes in body tissues

  18. Arterial spin labelling reveals prolonged arterial arrival time in idiopathic Parkinson's disease.

    Science.gov (United States)

    Al-Bachari, Sarah; Parkes, Laura M; Vidyasagar, Rishma; Hanby, Martha F; Tharaken, Vivek; Leroi, Iracema; Emsley, Hedley C A

    2014-01-01

    Idiopathic Parkinson's disease (IPD) is the second most common neurodegenerative disease, yet effective disease modifying treatments are still lacking. Neurodegeneration involves multiple interacting pathological pathways. The extent to which neurovascular mechanisms are involved is not well defined in IPD. We aimed to determine whether novel magnetic resonance imaging (MRI) techniques, including arterial spin labelling (ASL) quantification of cerebral perfusion, can reveal altered neurovascular status (NVS) in IPD. Fourteen participants with IPD (mean ± SD age 65.1 ± 5.9 years) and 14 age and cardiovascular risk factor matched control participants (mean ± SD age 64.6 ± 4.2 years) underwent a 3T MRI scan protocol. ASL images were collected before, during and after a 6 minute hypercapnic challenge. FLAIR images were used to determine white matter lesion score. Quantitative images of cerebral blood flow (CBF) and arterial arrival time (AAT) were calculated from the ASL data both at rest and during hypercapnia. Cerebrovascular reactivity (CVR) images were calculated, depicting the change in CBF and AAT relative to the change in end-tidal CO2. A significant (p = 0.005) increase in whole brain averaged baseline AAT was observed in IPD participants (mean ± SD age 1532 ± 138 ms) compared to controls (mean ± SD age 1335 ± 165 ms). Voxel-wise analysis revealed this to be widespread across the brain. However, there were no statistically significant differences in white matter lesion score, CBF, or CVR between patients and controls. Regional CBF, but not AAT, in the IPD group was found to correlate positively with Montreal cognitive assessment (MoCA) scores. These findings provide further evidence of alterations in NVS in IPD.

  19. Programming Post-Translational Control over the Metabolic Labeling of Cellular Proteins with a Noncanonical Amino Acid.

    Science.gov (United States)

    Thomas, Emily E; Pandey, Naresh; Knudsen, Sarah; Ball, Zachary T; Silberg, Jonathan J

    2017-08-18

    Transcriptional control can be used to program cells to label proteins with noncanonical amino acids by regulating the expression of orthogonal aminoacyl tRNA synthetases (aaRSs). However, we cannot yet program cells to control labeling in response to aaRS and ligand binding. To identify aaRSs whose activities can be regulated by interactions with ligands, we used a combinatorial approach to discover fragmented variants of Escherichia coli methionyl tRNA synthetase (MetRS) that require fusion to associating proteins for maximal activity. We found that these split proteins could be leveraged to create ligand-dependent MetRS using two approaches. When a pair of MetRS fragments was fused to FKBP12 and the FKBP-rapamycin binding domain (FRB) of mTOR and mutations were introduced that direct substrate specificity toward azidonorleucine (Anl), Anl metabolic labeling was significantly enhanced in growth medium containing rapamycin, which stabilizes the FKBP12-FRB complex. In addition, fusion of MetRS fragments to the termini of the ligand-binding domain of the estrogen receptor yielded proteins whose Anl metabolic labeling was significantly enhanced when 4-hydroxytamoxifen (4-HT) was added to the growth medium. These findings suggest that split MetRS can be fused to a range of ligand-binding proteins to create aaRSs whose metabolic labeling activities depend upon post-translational interactions with ligands.

  20. Synthesis and tissue distribution of fluorine-18 labeled trifluorohexadecanoic acids. Considerations in the development of metabolically blocked myocardial imaging agents

    International Nuclear Information System (INIS)

    Pochapsky, S.S.; Katzenellenbogen, J.A.; VanBrocklin, H.F.; Welch, M.J.

    1990-01-01

    A versatile method for the synthesis of trifluoro fatty acids, potential metabolically blocked myocardial imaging agents, has been developed. Two trifluorohexadecanoic (palmitic) acids have been prepared [6,6,16-trifluorohexadecanoic acid (I) and 7,7,16-trifluorohexadecanoic acid (II)], each of which bears two of the fluorine atoms as a gem-difluoromethylene unit on the fatty acid chain (at C-6 or C-7) and the third at the ω (C-16) position. The metabolic stability of carbon-fluorine bonds suggests the gem-difluoro group may block the β-oxidation pathway, while the terminal fluorine could be the site for labeling with fluorine-18. The convergent synthetic approach utilizes a 2-lithio-1,3-dithiane derived from 10-undecenal or 9-decenal, which is alkylated with the OBO (oxabicyclooctyl) ester of 5-bromopentanoic acid or 6-bromohexanoic acid, respectively. Hydroboration-oxidation and alcohol protection are followed by halofluorination to convert the 1,3-dithiane system to a gem-difluoro group. The third fluorine is introduced by fluoride ion displacement of a trifluoromethanesulfonate. This synthesis is adapted to the labeling of these trifluoro fatty acids with the short-lived radionuclide fluorine-18 (t 1/2 = 110 min), with the third fluorine introduced as fluoride ion in the penultimate step. The radiochemical syntheses proceed in 3-34% radiochemical yield (decay corrected), with an overall synthesis and purification time of 90 min. Tissue distribution studies in rats were performed with I and II, as well as with 16-[ 18 F]fluoropalmitic acid (III), [ 11 C]palmitic acid, and [ 11 C]octanoic acid. The heart uptake of the fluoropalmitic acids decreases with substitution, the 2-min activity level for 16-fluoropalmitic acid being 65% and that for both 6,6,16-and 7,7,17-trifluoropalmitic acids being 30% that of palmitic acid

  1. Characterizing Slow Chemical Exchange in Nucleic Acids by Carbon CEST and Low Spin-Lock Field R1ρ NMR Spectroscopy

    Science.gov (United States)

    Zhao, Bo; Hansen, Alexandar L.; Zhang, Qi

    2016-01-01

    Quantitative characterization of dynamic exchange between various conformational states provides essential insights into the molecular basis of many regulatory RNA functions. Here, we present an application of nucleic-acid-optimized carbon chemical exchange saturation transfer (CEST) and low spin-lock field R1ρ relaxation dispersion (RD) NMR experiments in characterizing slow chemical exchange in nucleic acids that is otherwise difficult if not impossible to be quantified by the ZZ-exchange NMR experiment. We demonstrated the application on a 47-nucleotide fluoride riboswitch in the ligand-free state, for which CEST and R1ρ RD profiles of base and sugar carbons revealed slow exchange dynamics involving a sparsely populated (p ~ 10%) and shortly lived (τ ~ 10 ms) NMR “invisible” state. The utility of CEST and low spin-lock field R1ρ RD experiments in studying slow exchange was further validated in characterizing an exchange as slow as ~60 s−1. PMID:24299272

  2. Characterizing slow chemical exchange in nucleic acids by carbon CEST and low spin-lock field R(1ρ) NMR spectroscopy.

    Science.gov (United States)

    Zhao, Bo; Hansen, Alexandar L; Zhang, Qi

    2014-01-08

    Quantitative characterization of dynamic exchange between various conformational states provides essential insights into the molecular basis of many regulatory RNA functions. Here, we present an application of nucleic-acid-optimized carbon chemical exchange saturation transfer (CEST) and low spin-lock field R(1ρ) relaxation dispersion (RD) NMR experiments in characterizing slow chemical exchange in nucleic acids that is otherwise difficult if not impossible to be quantified by the ZZ-exchange NMR experiment. We demonstrated the application on a 47-nucleotide fluoride riboswitch in the ligand-free state, for which CEST and R(1ρ) RD profiles of base and sugar carbons revealed slow exchange dynamics involving a sparsely populated (p ~ 10%) and shortly lived (τ ~ 10 ms) NMR "invisible" state. The utility of CEST and low spin-lock field R(1ρ) RD experiments in studying slow exchange was further validated in characterizing an exchange as slow as ~60 s(-1).

  3. Myocardial distribution of I/sup 131/-labeled hexadecenoic acid in relation to the dog local coronary flow

    Energy Technology Data Exchange (ETDEWEB)

    Riche, F.; Busquet, G.; Pilichowski, P.; Wolf, J.E.; Mathieu, J.P.; Comet, M.; Pernin, C. (Centre Hospitalier Regional, 38 - Grenoble (France)); Vidal, M.; Vincens, M.; Godart, J. (Grenoble-1 Univ., 38 (France). Inst. des Sciences Nucleaires)

    1981-01-01

    20 anesthetized and thoracotomized dogs are studied. The local myocardial blood flow is measured with sup(99m)Tc human albumin microspheres. The intramyocardial distribution of the 16-I(131)-9-hexadecenoic acid in relation to local blood flow is studied in basal conditions (7 dogs), after experimental infarction (6 dogs) and postischemic reactive hyperhemia (7 dogs). We conclude that during basal condition, after infarction but not during reactive hyperhemia, the distribution of the labeled fatty acid reflect the local variations of blood flow.

  4. Application of 123I-labelled long-chained fatty acids for the study of myocardial metabolism

    International Nuclear Information System (INIS)

    Freundlieb, C.; Hoeck, A.; Vyska, F.; Feinendegen, L.E.; Machulla, H.J.; Stoecklin, G.

    1978-01-01

    Radioiodine-labelled fatty acids are useful tracers for myocardial imaging. The present study extends myocardial scintigraphy with ω-123-I-heptadecanoic acid to measuring myocardial metabolism. 4 normal individuals and 6 patients with cardiac disease received i.v. 1-2 mCi ω-123-I-heptadecanoic acid. Immediately fast serial scintigrams of the myocardium were taken for 30 minutes. Disappearance of the tracer, and appearance of anorganic 123-I, was measured in the peripheral blood. The myocardial images were of high quality later than 5 minutes after injection. By correcting for anorganic 123-I in the peripheral blood and the interstitium, the turnover of tracer in the myocardial cells could be measured. Activity was lost from the myocardium with a half time between 14 and 32 minutes. Within regions of old myocardials infarctions the half time of tracer loss was prolonged. The data clearly indicate the feasibility of using ω-123-I-heptadecanoic acid for measuring myocardial metabolism. (author)

  5. Hepatic handling of a synthetic gamma-labeled bile acid (75SeHCAT)

    International Nuclear Information System (INIS)

    Galatola, G.; Jazrawi, R.P.; Bridges, C.; Joseph, A.E.; Northfield, T.C.

    1988-01-01

    75 Se-homocholic acid-taurine ( 75 SeHCAT) is the first available gamma-labeled bile acid, and should therefore be handled more efficiently and specifically by the liver than previous hepatoscintigraphic agents. We have measured serum and hepatic kinetics for 75 SeHCAT, and compared them with those for the conventional hepatobiliary scintigraphic agent 99mTc-hepatoiminodiacetic acid, and with serum kinetics for the corresponding natural bile acid, [ 14 C]cholic acid-taurine. We used a dynamic scintigraphic technique and serial blood sampling in 8 subjects. Initial hepatic uptake rate was identical to initial serum disappearance rate (14% dose/min) for 75 SeHCAT, but significantly lower for 99mTc-hepatoiminodiacetic acid (6% vs. 14% dose/min, p less than 0.001). Hepatic transit time was shorter for 75 SeHCAT (13 min vs. 22 min, p less than 0.02), net hepatic excretory rate was more rapid (1.4% vs. 0.8% dose/min, p less than 0.001), and urinary excretion was lower (1.0% vs. 9.0% dose, p less than 0.001). Initial and late-plasma disappearance rates were significantly lower for 75 SeHCAT (14.3% and 1.5% dose/min) than for [ 14 C]cholic acid-taurine (21.3% and 2.8% dose/min, respectively), and plasma clearance was also lower (2 75 vs. 670 ml/min). In vitro, 75 SeHCAT was bound to serum proteins more completely than [ 14 C]cholic acid-taurine (90.4% vs. 86.5%, p less than 0.005). We conclude that 75 SeHCAT provides a hepatoscintigraphic agent that is handled more efficiently and specifically by the liver than the conventionally used agent 99mTc-hepatoiminodiacetic acid. It is not cleared from the serum as rapidly as [ 14 C]cholic acid-taurine, probably due to its stronger protein binding. The clinical value of 75 SeHCAT in assessing liver disease should be investigated

  6. Influence of the glutamic acid content of the diet on the catabolic rate of labelled glutamic acid in rats. 3

    International Nuclear Information System (INIS)

    Simon, O.; Wilke, A.; Bergner, H.

    1984-01-01

    Mal rats received during a 8 days experimental feeding period diets with different contents in glutamic acid. The daily feed intake was restricted to the energy maintenance level of 460 kJ/kg/sup 0.75/. The diet contained a mixture of L-amino acids corresponding to the pattern of egg protein except glutamic acid. Glutamic acid was added successively at 10 levels (0 to 14.8 % of dry matter) and the resulting diets were fed to groups of 4 animals each. At the end of the experimental feeding period 14 C- and 15 N-labelled glutamic acid were applied by intragastric infusion. CO 2 and 14 CO 2 excretion was measured during the following 4 hours and the urinary N and 15 N excretion during the following 24 hours. The CO 2 excretion decreased from 53 to 44 mmol CO 2 /100g body weight with increasing levels of dietary glutamic acid. This change seems to result from the increasing proportion of amino acids as an energetic fuel. While the amount of oxidized glutamic acid increased with increasing supplements of glutamic acid the relative 14 CO 2 excretion decreased from 57 to 48 % of the applied radioactivity. The urinary 15 N excretion during 24 hours was 31 % of the given amount of 15 N if no glutamic acid was included in the diet. This proportion increased successively up to 52 % in the case of the highest supply of glutamic acid. Because the total N excretion increased at the same extent as the 15 N excretion a complete mixing of the NH 2 groups resulting from glutamic acid due to desamination with the ammonia pool was assumed. No correlation between glutamic acid content of the diet and specific radioactivity of CO 2 or atom-% 15 N excess of urinary N was observed. (author)

  7. Double-labeled donor probe can enhance the signal of fluorescence resonance energy transfer (FRET) in detection of nucleic acid hybridization

    Science.gov (United States)

    Okamura, Yukio; Kondo, Satoshi; Sase, Ichiro; Suga, Takayuki; Mise, Kazuyuki; Furusawa, Iwao; Kawakami, Shigeki; Watanabe, Yuichiro

    2000-01-01

    A set of fluorescently-labeled DNA probes that hybridize with the target RNA and produce fluorescence resonance energy transfer (FRET) signals can be utilized for the detection of specific RNA. We have developed probe sets to detect and discriminate single-strand RNA molecules of plant viral genome, and sought a method to improve the FRET signals to handle in vivo applications. Consequently, we found that a double-labeled donor probe labeled with Bodipy dye yielded a remarkable increase in fluorescence intensity compared to a single-labeled donor probe used in an ordinary FRET. This double-labeled donor system can be easily applied to improve various FRET probes since the dependence upon sequence and label position in enhancement is not as strict. Furthermore this method could be applied to other nucleic acid substances, such as oligo RNA and phosphorothioate oligonucleotides (S-oligos) to enhance FRET signal. Although the double-labeled donor probes labeled with a variety of fluorophores had unexpected properties (strange UV-visible absorption spectra, decrease of intensity and decay of donor fluorescence) compared with single-labeled ones, they had no relation to FRET enhancement. This signal amplification mechanism cannot be explained simply based on our current results and knowledge of FRET. Yet it is possible to utilize this double-labeled donor system in various applications of FRET as a simple signal-enhancement method. PMID:11121494

  8. Spectroscopic Evidence for Covalent Binding of Sulfadiazine to Natural Soils via 1,4-nucleophilic addition (Michael Type Addition) studied by Spin Labeling ESR

    Science.gov (United States)

    Aleksandrova, Olga

    2015-04-01

    with different polarity. As shown by the spin labeling ESR experiment, molecules modeling SDZ were promptly bound to non-hydrolysable network of soil organic matter only via the aromatic amines that was accompanied by a prompt enlargement of humic particles binding aromatic amines, whereas binding of decomposition products of SDZ to humic acids of soil via the aliphatic amines was not observable. The ESR spectra obviously showed a single-phase process of covalent binding of the aromatic amines. Repeated washouts of labeled soil samples using distil water and ultrafiltration through the membrane of 5000 MWCO PES confirmed irreversible binding of the aromatic amines, and showed that via the aliphatic amines, binding of SDZ or decomposition products of SDZ to soil might also occur but reversibly and only to small soil molecules, which don't enter into the composition of non-hydrolysable part of soil organic matter. SL ESR experiments of different soils at the presence of Laccase highlighted that covalent binding of the aromatic amines to humic particles occurred in the specific hydrophobic areas of soil found as depleted in oxygen. All measured data evidenced that first, SDZ might be decomposed that allowed for measuring the same change of a paramagnetic signal of soil organic matter influenced by both aromatic and aliphatic amines as in the experiment of the interaction of soil with SDZ. Second, a decomposition product of SDZ with the aromatic amine might be bound to non-hydrolysable parts of soil organic matter under specific anaerobic conditions only via 1,4 - nucleophilic addition, Michael-type addition. Gulkowska, A., Thalmann, B., D., Hollender, J., & Krauss, M. (2014). Chemosphere, 107, 366 - 372. Müller, T., Rosendahl, I., Focks, A., Siemens, J., Klasmeier, J., & Matthies. (2013). Environmental Pollution, 172,180 - 185. Nowak, K.M., Miltner, A., Gehre, M., Schaeffer, A., & Kaestner, M. (2011). Environmental Science & Technology 45, 999 - 1006. Weber, E.J., Spidle

  9. Use of resonance ionization spectroscopy to detect DNA bands on ultrathin spin-coated gels.

    Science.gov (United States)

    Doktycz, M J; Gibson, W A; Arlinghaus, H F; Allen, R C; Jacobson, K B

    1993-01-01

    Development of alternative electrophoresis procedures are necessary for large volume sequencing and mapping studies. The use of stable isotopes as DNA labels and ultrathin gels promises to greatly increase the rate of sequencing. Spin coating is presented as an alternative method for producing ultrathin polyacrylamide gels. The technique has the potential of producing gels of micron to submicron thicknesses by varying the viscosity of the acrylamide solution and the spinning speed. Thirty micron thick 6% (weight %) gels were produced in this manner. Tin-labeled DNA oligomers were electrophoresed and detected using sputter-initiated resonance ionization spectroscopy (SIRIS). The usefulness of SIRIS and laser atomization RIS (LARIS) to sample the surface and deeper layers of 240 microns thick gels was investigated. With LARIS, whole cross-sections of the gel can be atomized, possibly allowing complete sampling of labels.

  10. A neuroradiologist's guide to arterial spin labeling MRI in clinical practice

    International Nuclear Information System (INIS)

    Grade, M.; Hernandez Tamames, J.A.; Pizzini, F.B.; Achten, E.; Golay, X.; Smits, M.

    2015-01-01

    Arterial spin labeling (ASL) is a non-invasive MRI technique to measure cerebral blood flow (CBF). This review provides a practical guide and overview of the clinical applications of ASL of the brain, as well its potential pitfalls. The technical and physiological background is also addressed. At present, main areas of interest are cerebrovascular disease, dementia and neuro-oncology. In cerebrovascular disease, ASL is of particular interest owing to its quantitative nature and its capability to determine cerebral arterial territories. In acute stroke, the source of the collateral blood supply in the penumbra may be visualised. In chronic cerebrovascular disease, the extent and severity of compromised cerebral perfusion can be visualised, which may be used to guide therapeutic or preventative intervention. ASL has potential for the detection and follow-up of arteriovenous malformations. In the workup of dementia patients, ASL is proposed as a diagnostic alternative to PET. It can easily be added to the routinely performed structural MRI examination. In patients with established Alzheimer's disease and frontotemporal dementia, hypoperfusion patterns are seen that are similar to hypometabolism patterns seen with PET. Studies on ASL in brain tumour imaging indicate a high correlation between areas of increased CBF as measured with ASL and increased cerebral blood volume as measured with dynamic susceptibility contrast-enhanced perfusion imaging. Major advantages of ASL for brain tumour imaging are the fact that CBF measurements are not influenced by breakdown of the blood-brain barrier, as well as its quantitative nature, facilitating multicentre and longitudinal studies. (orig.)

  11. A neuroradiologist's guide to arterial spin labeling MRI in clinical practice

    Energy Technology Data Exchange (ETDEWEB)

    Grade, M. [Queen Square, UCL Institute of Neurology, London (United Kingdom); Stanford School of Medicine, Stanford, CA (United States); Hernandez Tamames, J.A. [Rey Juan Carlos University, Medical Image Analysis and Biometry Laboratory, Madrid (Spain); Erasmus MC - University Medical Centre Rotterdam, Department of Radiology, PO Box 2040, Rotterdam (Netherlands); Pizzini, F.B. [Queen Square, UCL Institute of Neurology, London (United Kingdom); Verona University Hospital, Neuroradiology, Department of Diagnostics and Pathology, Verona (Italy); Achten, E. [Ghent University Hospital, Neuroradiology, Department of Radiology, Ghent (Belgium); Golay, X. [Queen Square, UCL Institute of Neurology, London (United Kingdom); Smits, M. [Erasmus MC - University Medical Centre Rotterdam, Department of Radiology, PO Box 2040, Rotterdam (Netherlands)

    2015-12-15

    Arterial spin labeling (ASL) is a non-invasive MRI technique to measure cerebral blood flow (CBF). This review provides a practical guide and overview of the clinical applications of ASL of the brain, as well its potential pitfalls. The technical and physiological background is also addressed. At present, main areas of interest are cerebrovascular disease, dementia and neuro-oncology. In cerebrovascular disease, ASL is of particular interest owing to its quantitative nature and its capability to determine cerebral arterial territories. In acute stroke, the source of the collateral blood supply in the penumbra may be visualised. In chronic cerebrovascular disease, the extent and severity of compromised cerebral perfusion can be visualised, which may be used to guide therapeutic or preventative intervention. ASL has potential for the detection and follow-up of arteriovenous malformations. In the workup of dementia patients, ASL is proposed as a diagnostic alternative to PET. It can easily be added to the routinely performed structural MRI examination. In patients with established Alzheimer's disease and frontotemporal dementia, hypoperfusion patterns are seen that are similar to hypometabolism patterns seen with PET. Studies on ASL in brain tumour imaging indicate a high correlation between areas of increased CBF as measured with ASL and increased cerebral blood volume as measured with dynamic susceptibility contrast-enhanced perfusion imaging. Major advantages of ASL for brain tumour imaging are the fact that CBF measurements are not influenced by breakdown of the blood-brain barrier, as well as its quantitative nature, facilitating multicentre and longitudinal studies. (orig.)

  12. Dansyl labeling to modulate the relative affinity of bile acids for the binding sites of human serum albumin.

    Science.gov (United States)

    Rohacova, Jana; Sastre, German; Marin, M Luisa; Miranda, Miguel A

    2011-09-08

    Binding of natural bile acids to human serum albumin (HSA) is an important step in enterohepatic circulation and provides a measure of liver function. In this article, we report on the use of four dansyl (Dns) derivatives of cholic acid (ChA) to demonstrate a regiodifferentiation in their relative affinity for the two binding sites of HSA. Using both steady-state and time-resolved fluorescence, formation of Dns-ChA@HSA complexes was confirmed; the corresponding binding constants were determined, and their distribution between bulk solution and HSA microenvironment was estimated. By means of energy transfer from Trp to the Dns moiety, donor-acceptor distances were estimated (21-25 Å) and found to be compatible with both site 1 and site 2 occupancies. Nevertheless, titration using warfarin and ibuprofen as specific displacement probes clearly indicated that 3α- and 3β-Dns-ChA bind to HSA at site 2, whereas their C-7 regioisomers bind to HSA at site 1. Furthermore, the C-3-labeled compounds are displaced by lithocholic acid, whereas they are insensitive to ChA, confirming the assumption that the former binds to HSA at site 2. Thus, Dns labeling provides a useful tool to modulate the relative affinity of ChA to the major binding sites of HSA and, in combination with other fluorescent ChA analogs, to mimic the binding behavior of natural bile acids.

  13. Detection of chitinase activity by 2-aminobenzoic acid labeling of chito-oligosaccharides.

    Science.gov (United States)

    Ghauharali-van der Vlugt, Karen; Bussink, Anton P; Groener, Johanna E M; Boot, Rolf G; Aerts, Johannes M F G

    2009-01-01

    Chitinases are hydrolases capable of hydrolyzing the abundant natural polysaccharide chitin. Next to artificial fluorescent substrates, more physiological chito-oligomers are commonly used in chitinase assays. Analysis of chito-oligosaccharides products is generally accomplished by UV detection. However, the relatively poor sensitivity poses a serious limitation. Here we report on a novel, much more sensitive assay for the detection of chito-oligosaccharide reaction products released by chitinases, based on fluorescent detection, following chemical labeling by 2-aminobenzoic acid. Comparison with existing UV-based assays, shows that the novel assay offers the same advantages yet allows detection of chito-oligosaccharides in the low picomolar range.

  14. Preparation of 2-[125I] iodohistamine-labelled Δ8-tetrahydrocannabinol-11-oic acid for use in cannabinoid radioimmunoassay

    International Nuclear Information System (INIS)

    Law, B.; Mason, P.A.; Moffat, A.C.; King, L.J.

    1982-01-01

    A simple method is described for the preparation of 2-[ 125 I]iodohistamine-labelled Δ 8 -tetrahydrocannabinol-11-oic acid with high specific activity for use in radioimmunoassay. This compound is produced in high yield and shows excellent radiochemical stability when stored at 4 0 C. (author)

  15. Protein labelling with stable isotopes: strategies

    International Nuclear Information System (INIS)

    Lirsac, P.N.; Gilles, N.; Jamin, N.; Toma, F.; Gabrielsen, O.; Boulain, J.C.; Menez, A.

    1994-01-01

    A protein labelling technique with stable isotopes has been developed at the CEA: a labelled complete medium has been developed, performing as well as the Luria medium, but differing from it because it contains not only free aminated acids and peptides, but also sugars (96% of D-glucopyrannose) and labelled nucleosides. These precursors are produced from a labelled photosynthetic micro-organisms biomass, obtained with micro-algae having incorporated carbon 13, nitrogen 15 and deuterium during their culture. Labelling costs are reduced. 1 fig., 1 tab., 3 refs

  16. Preparation of labelled lipids by the use of plant cell cultures

    International Nuclear Information System (INIS)

    Mangold, H.K.

    1978-01-01

    The preparation of some radioacitvely labelled lipids by the use of plant cell cultures is discussed and further applications of the new method are suggested. Cell suspension cultures of rape (Brassica napus) and soya (Glycine max) have been used for the preparation of lipids labelled with radioisotopes. Radioactive acetic acid as well as various long-chain fatty acids are readily incorporated into the neutral and ionic lipids of plant cell cultures. In addition, 14 C-labelled glycerol, ethanolamine and choline are well utilized by the cells. Randomly labelled lipids have been obtained by incubating cell suspension cultures of rape and soya with [1- 14 C] acetic acid, and uniformly labelled lipids have been isolated from cultures that had been incubated with a mixture of [1- 14 C] acetic acid plus [2- 14 C] acetic acid. The use of techniques of plant cell cultures for the preparation of lipds labelled with stable or radioactive isotopesappears particularly rewarding because the uptake of precursors by the cells and their incorporation into various lipid compounds proceeds rapidly and often quanitatively.This new approach should be useful also for the biosynthesis of lipids whose acyl moieties contain a spn radical, a fluorescent group, or a light-sensitive label. Thus, plant cell cultures constitute valuable new tools for the biosynthetic preparation of a great variety of labelled lipids. (A.G.)

  17. 13C spin relaxation measurements in RNA: Sensitivity and resolution improvement using spin-state selective correlation experiments

    International Nuclear Information System (INIS)

    Boisbouvier, Jerome; Brutscher, Bernhard; Simorre, Jean-Pierre; Marion, Dominique

    1999-01-01

    A set of new NMR pulse sequences has been designed for the measurement of 13 C relaxation rate constants in RNA and DNA bases: the spin-lattice relaxation rate constant R(C z ), the spin-spin relaxation rate constant R(C + ), and the CSA-dipolar cross-correlated relaxation rate constant Γ C,CH xy . The use of spin-state selective correlation techniques provides increased sensitivity and spectral resolution. Sensitivity optimised C-C filters are included in the pulse schemes for the suppression of signals originating from undesired carbon isotopomers. The experiments are applied to a 15% 13 C-labelled 33-mer RNA-theophylline complex. The measured R(C + )/Γ C,CH xy ratios indicate that 13 C CSA tensors do not vary significantly for the same type of carbon (C 2 , C 6 , C 8 ), but that they differ from one type to another. In addition, conformational exchange effects in the RNA bases are detected as a change in the relaxation decay of the narrow 13 C doublet component when varying the spacing of a CPMG pulse train. This new approach allows the detection of small exchange effects with a higher precision compared to conventional techniques

  18. Technetium and rhenium complexes with modified fatty acid ligands 4. Evaluation of two new classes of {sup 99m}Tc-labelled fatty acids as potential tracers for myocardial metabolism imaging

    Energy Technology Data Exchange (ETDEWEB)

    Heintz, A.; Kropp, J.; Deussen, A. [TU Dresden, Medizinische Fakultaet Carl Gustav Carus (Germany); Jung, C.M.; Spies, H.

    2002-01-01

    {sup 99m}Tc-labelled fatty acids were synthesized according to the '3+1' mixed-ligand approach and investigated as potential tracers for myocardial SPECT diagnostics on the model of the isolated guinea pig heart. The results indicate a low but specific myocardial uptake of the {sup 99m}Tc fatty acid derivatives subject to chain length and structure. (orig.)

  19. Measurement of cerebral white matter perfusion using pseudocontinuous arterial spin labeling 3T magnetic resonance imaging--an experimental and theoretical investigation of feasibility.

    Directory of Open Access Journals (Sweden)

    Wen-Chau Wu

    Full Text Available PURPOSE: This study was aimed to experimentally and numerically investigate the feasibility of measuring cerebral white matter perfusion using pseudocontinuous arterial spin labeling (PCASL 3T magnetic resonance imaging (MRI at a relatively fine resolution to mitigate partial volume effect from gray matter. MATERIALS AND METHODS: The Institutional Research Ethics Committee approved this study. On a clinical 3T MR system, ten healthy volunteers (5 females, 5 males, age = 28 ± 3 years were scanned after providing written informed consent. PCASL imaging was performed with varied combinations of labeling duration (τ = 1000, 1500, 2000, and 2500 ms and post-labeling delay (PLD = 1000, 1400, 1800, and 2200 ms, at a spatial resolution (1.56 x 1.56 x 5 mm(3 finer than commonly used (3.5 x 3.5 mm(2, 5-8 mm in thickness. Computer simulations were performed to calculate the achievable perfusion-weighted signal-to-noise ratio at varied τ, PLD, and transit delay. RESULTS: Based on experimental and numerical data, the optimal τ and PLD were found to be 2000 ms and 1500-1800 ms, respectively, yielding adequate SNR (~2 to support perfusion measurement in the majority (~60% of white matter. The measurement variability was about 9% in a one-week interval. The measured white matter perfusion and perfusion ratio of gray matter to white matter were 15.8-27.5 ml/100ml/min and 1.8-4.0, respectively, depending on spatial resolution as well as the amount of deep white matter included. CONCLUSION: PCASL 3T MRI is able to measure perfusion in the majority of cerebral white matter at an adequate signal-to-noise ratio by using appropriate tagging duration and post-labeling delay. Although pixel-wise comparison may not be possible, region-of-interest based flow quantification is feasible.

  20. Probing the interaction of brain fatty acid binding protein (B-FABP with model membranes.

    Directory of Open Access Journals (Sweden)

    Fábio Dyszy

    Full Text Available Brain fatty acid-binding protein (B-FABP interacts with biological membranes and delivers polyunsaturated fatty acids (FAs via a collisional mechanism. The binding of FAs in the protein and the interaction with membranes involve a motif called "portal region", formed by two small α-helices, A1 and A2, connected by a loop. We used a combination of site-directed mutagenesis and electron spin resonance to probe the changes in the protein and in the membrane model induced by their interaction. Spin labeled B-FABP mutants and lipidic spin probes incorporated into a membrane model confirmed that B-FABP interacts with micelles through the portal region and led to structural changes in the protein as well in the micelles. These changes were greater in the presence of LPG when compared to the LPC models. ESR spectra of B-FABP labeled mutants showed the presence of two groups of residues that responded to the presence of micelles in opposite ways. In the presence of lysophospholipids, group I of residues, whose side chains point outwards from the contact region between the helices, had their mobility decreased in an environment of lower polarity when compared to the same residues in solution. The second group, composed by residues with side chains situated at the interface between the α-helices, experienced an increase in mobility in the presence of the model membranes. These modifications in the ESR spectra of B-FABP mutants are compatible with a less ordered structure of the portal region inner residues (group II that is likely to facilitate the delivery of FAs to target membranes. On the other hand, residues in group I and micelle components have their mobilities decreased probably as a result of the formation of a collisional complex. Our results bring new insights for the understanding of the gating and delivery mechanisms of FABPs.

  1. Synthesis of tritium-labeled fosfomycin

    International Nuclear Information System (INIS)

    Mertel, H.E.; Meriwether, H.T.

    1982-01-01

    Tritium gas was used as a labeling agent for the preparation of [1,2- 3 H]fosfomycin. Introduction of tritium into a precursor, the synthesis including resolution of the intermediate racemic 1,2-epoxypropylphosphonic acid, and preparation of both amine and calcium salts of the labeled antibiotic are described. (author)

  2. Na+/substrate Coupling in the Multidrug Antiporter NorM Probed with a Spin-labeled Substrate

    Science.gov (United States)

    Steed, P. Ryan; Stein, Richard A.; Mishra, Smriti; Goodman, Michael C.; Mchaourab, Hassane S.

    2013-01-01

    NorM of the multidrug and toxic compound extrusion (MATE) family of transporters couples the efflux of a broad range of hydrophobic molecules to an inward Na+ gradient across the cell membrane. Several crystal structures of MATE transporters revealed distinct substrate binding sites leading to differing models of the mechanism of ion-coupled substrate extrusion. In the experiments reported here, we observed that a spin-labeled derivative of daunorubicin, Ruboxyl, is transported by NorM from Vibrio cholerae. It is therefore ideal to characterize mechanistically relevant binding interactions with NorM and to directly address the coupling of ion and drug binding. Fluorescence and EPR experiments revealed that Ruboxyl binds to NorM with micromolar affinity and becomes immobilized upon binding, even in the presence of Na+. Using double electron-electron resonance (DEER) spectroscopy, we determined that Ruboxyl binds to a single site on the periplasmic side of the protein. The presence of Na+ did not translocate the substrate to a second site as previously proposed. These experiments surprisingly show that Na+ does not affect the affinity or location of the substrate binding site on detergent-solubilized NorM, thus suggesting that additional factors beyond simple mutual exclusivity of binding, such as the presence of a Na+ gradient across the native membrane, govern Na+/drug coupling during antiport. PMID:23902581

  3. Comparing kidney perfusion using noncontrast arterial spin labeling MRI and microsphere methods in an interventional swine model.

    Science.gov (United States)

    Artz, Nathan S; Wentland, Andrew L; Sadowski, Elizabeth A; Djamali, Arjang; Grist, Thomas M; Seo, Songwon; Fain, Sean B

    2011-02-01

    The purpose of this study was to assess the ability of a flow-sensitive alternating inversion recovery-arterial spin labeling (FAIR-ASL) technique to track renal perfusion changes during pharmacologic and physiologic alterations in renal blood flow using microspheres as a gold standard. Fluorescent microsphere and FAIR-ASL perfusion were compared in the cortex of the kidney for 11 swine across 4 interventional time points: (1) under baseline conditions, (2) during an acetylcholine and fluid bolus challenge to increase perfusion, (3) initially after switching to isoflurane anesthesia, and (4) after 2 hours of isoflurane anesthesia. In 10 of the 11 swine, a bag of ice was placed on the hilum of 1 kidney at the beginning of isoflurane administration to further reduce perfusion in 1 kidney. Both ASL and microspheres tracked the expected cortical perfusion changes (P values were systematically lower compared with microsphere perfusion. Very good correlation (r = 0.81, P values in the expected physiologic range (microsphere perfusion values saturated for perfusion >550 mL/min/100 g. Cortical perfusion measured with ASL correlated with microspheres and reliably detected changes in renal perfusion in response to physiologic challenge.

  4. Assessment of glioma response to radiotherapy using 3D pulsed-continuous arterial spin labeling and 3D segmented volume

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Peng; Li, Jianrui; Diao, Qiang; Lin, YuanKai; Zhang, Jun; Li, Lin; Yang, Gang; Fang, Xiaokun; Li, Xie; Chen, YingQi; Zheng, Ling, E-mail: lingzheng1989@yeah.net; Lu, Guangming, E-mail: guangminglu1905@163.com

    2016-11-15

    Background: Gliomas are the most common primary brain tumors in adults, in some cases, radiotherapy may be the preferred treatment option especially for elderly people who cannot endure surgery. Therefore, it is necessary to evaluate the effects of radiotherapy on glioma. Arterial spin labeling (ASL) is an MR imaging technique that allows for a quantitative determination of cerebral blood flow (CBF) noninvasively. Tumor volume is still an important determinant for evaluating treatment response. The purpose of this study was to investigate the relationship between the tumor perfusion parameters and tumor volume and assess the effects of radiotherapy on glioma using pulsed-continuous arterial spin labeling (pcASL) technique. Methods: 35 patients with gliomas, histologically classified as low-grade group (n = 16) and high-grade group (n = 19), treated with radiotherapy only or before using other therapies were included in this study. MR examinations, including T1 weighted image and pcASL, were performed before and 4, 8, 12, 16 weeks after radiotherapy. Regional CBF of normal tissue, mean tumor blood flow (TBF{sub mean}), maximum tumor blood flow (TBF{sub max}), and tumor volume were evaluated at each time point. Both the percentage change in CBF (CBF ratio), TBF{sub mean} (TBF{sub mean} ratio), TBF{sub max} (TBF{sub max} ratio) and the percentage change in tumor volume (volume ratio) were calculated using values obtained before and after radiotherapy. The correlation between the volume ratio and CBF ratio, TBF{sub mean} ratio, TBF{sub max} ratio was assessed using linear regression analysis and Pearson’s correlation. Results: The TBF{sub mean} and TBF{sub max} of high-grade gliomas were significantly higher than that of low-grade group. In high-grade group, a strong correlation was demonstrated between the tumor volume and the TBF{sub max} before radiotherapy (R{sup 2} = 0.35, r{sub s} = 0.59, p < 0.05). There was also a significant correlation between the TBF

  5. Assessment of the effect of phytic acid on the labeling of blood cells and plasma proteins with Technetium-99m

    International Nuclear Information System (INIS)

    Lima-Filho, Guilherme L.; Freitas, Rosimeire S.; Moreno, Silvana R.F.; Boasquevisque, Edson M.; Bernardo-Filho, Mario; Lima, Glaydes M.T.; Catanho, Maria T.J.A.

    2002-01-01

    Blood elements labeled with technetium-99m ( 99m Tc) have been used in various procedures in nuclear medicine. We have investigated if phytic acid (PHY) could alter the labeling of blood elements with 99m Tc. Blood was incubated with different concentrations of PHY. Stannous chloride and 99m Tc, as sodium pertechnetate, were added. Blood was centrifuged and plasma (P) and blood cell (BC) were isolated. Samples of P and BC were also precipitated with trichloroacetic acid and centrifuged, and insoluble (IF) and soluble (SF) fractions were separated. The percentages of radioactivity (%ATI) in BC, IF-P and IF-BC were calculated. The %ATI decreased significantly (p 99m Tc with possible undesirable effects, it is relevant to verify the necessity to repeat the examination and to evaluate the increase of the radiation dose to the patient. (author)

  6. Comparative evaluation of labelling patterns and turnover of lipids, tagged by 15 (p-/sup 123/I-phenyl-)pentadecanoic and 1-/sup 14/C-palmitic acid

    Energy Technology Data Exchange (ETDEWEB)

    Reske, S.N.; Sauer, W.; Reichmann, K.; Winkler, C. (Bonn Univ. (Germany, F.R.). Inst. fuer Klinische und Experimentelle Nuklearmedizin); Machulla, H.J.; Knust, E.J. (Essen Univ. (Germany, F.R.). Inst. fuer Medizinische Strahlenphysik und Strahlenbiologie)

    1984-06-15

    Uptake and turnover of chloroform/methanol extractable tissue lipids labelled in vivo simultaneously with 15(p-/sup 123/I-phenyl-)pentadecanoic and 1-/sup 14/C-palmitic acid were compared. Lipid turnover studies were performed in fasted pentobarbital-anaesthetized Wistar rats in tissues with highly varying free fatty acid turnover rates. In all tissues investigated, i.e. heart, lung, liver, spleen and kidney, both tracers labelled nearly identical lipid fractions. The main tracer uptake was found in free fatty acids, phospholipids, diglycerides and triglycerides. A highly significant correlation of uptake and turnover in main tissue lipid fractions indicated an essentially identical metabolic pathway of both tracers in intermediary tissue lipid metabolism. Concordant tracer uptake and turnover patterns in tissue of lipids with highly varying fatty acid metabolic rates suggested that intrinsic metabolic activity of the tissue and respective lipid fraction was the major determinant of metabolic handling of both iodophenyl fatty- and palmitic acid. Thus, the feasibility of iodophenylpentadecanoic acid as free fatty acid tracer for studying tissue lipid metabolism is demonstrated. 21 refs.

  7. Radiophotosynthesis of some 14C-labelled amino acids using the unicellular green alga Scenedesmus acutus

    International Nuclear Information System (INIS)

    Barakat, M.F.; Farag, A.N.; Ragab, M.T.; El-Fouly, M.M.; El-Baz, F.K.

    1990-01-01

    Radiophotosynthesis has been carried out using the unicellular green algea Scenedesmus acutus grown, as a substrate for preparing some carbon-14 labelled amino acids. Gaseous 14 CO 2 , in an air tight photosynthesis chamber or NaH 14 CO 3 solution, in an ordinary phtosynthesis chamber, were used as radioactive carbon sources. The yields, radiochemical yields and specific activities of the formed radioactive products are reported in both cases. The results obtained clearly showed the advantages of usingthe NaH 14 CO 3 method. In that case the process was by far less tedious. Moreover, the chemical and radiochemical yields of the formed amino acids were relatively much more higher than the values obtained on using 14 CO 2 in the tight photosynthesis chamber. (orig.) [de

  8. Synthesis of no carrier added F-18 16-fluorohexadecanoic acid (FHDA) and investigation of its labeled metabolites and its kinetics in the heart

    International Nuclear Information System (INIS)

    DeGrado, T.R.; Bernstein, D.R.; Gatley, S.J.; Ng, C.K.; Holden, J.E.

    1984-01-01

    No carrier added FHDA was prepared via saponification of the product of silver oxide assisted reaction of near-anhydrous tetraethylammonium fluoride with methyl 16-iodohexadecanoate. The labeled fatty acid was injected into isolated perfused rat hearts. Coronary perfusate was collected for 4-9 minutes, when hearts were chilled and homogenized. F-18 in perfusate was analysed by HPLC (NH column; 50mM amm. acetate in 50% acetonitrile). Material with the same retention time as F-18 fluoroacetate (prepared by F-for-I exchange with ethyl iodoacetate) was found. Some F-18 stuck permanently to the column and was assigned as fluoride since the same fraction of label in perfusate was retained on alumina columns eluted with water. Anion exchange HPLC (SAX column; 20mM pot. phosphate, pH 7) of homogenates gave peaks corresponding to fluoroacetate plus fluoride and minor peaks which could be fluoroacetylCoA and fluorocitrate. The authors interpret their data as follows. Beta-oxidation of FHDA results in fluoroacetylCoA which either undergoes ''lethal synthesis'' to fluorocitrate or is hydrolysed to fluoroacetate which diffuses out of the heart. The source of the fluoride is not yet clear, but could complicate interpretation of FHDA kinetics measured in vivo with positron tomography. Clearance of label from FHDA in isolated perfused hearts was faster than for labeled 16-iodohexadecanoic acid, indicating that the F-18 tracer may be a more sensitive probe of myocardial fatty acid metabolism

  9. Radiosynthesis and in vitro evaluation of 99mTc(CO)3-labeled folic acid derivative

    International Nuclear Information System (INIS)

    Drishty Satpati; Archana Mukherjee; Meera Venkatesh; Sharmila Banerjee

    2011-01-01

    The over-expression of folate receptors in variety of neoplastic tissues makes radiolabeled folate conjugates potential agents for imaging and therapy of such cancers. With the aim of preparing an imaging agent for targeting folate receptors, folic acid has been conjugated with homocysteine for complexation with [ 99m Tc(CO) 3 (H 2 O) 3 ] + core. The radiolabeled complex of the homocysteine-folate could be obtained in >95% radiochemical yield as observed by HPLC. Stability of complex in saline was studied and challenge studies with histidine and cysteine revealed kinetic stability of the complex. Lipophilicity of the radiolabeled complex (log P) was found to be 0.45. In vitro uptake of 99m Tc(CO) 3 -labeled folic acid derivative was studied in KB cells and inhibition studies were carried out using 3 H-folic acid and cold homocysteine-folate conjugate. The in vitro studies indicated loss of binding affinity of the derivative towards folate receptors. (author)

  10. Correlating the P-31 NMR Chemical Shielding Tensor and the (2)J(P,C) Spin-Spin Coupling Constants with Torsion Angles zeta and alpha in the Backbone of Nucleic Acids

    Czech Academy of Sciences Publication Activity Database

    Benda, Ladislav; Sochorová Vokáčová, Zuzana; Straka, Michal; Sychrovský, Vladimír

    2012-01-01

    Roč. 116, č. 12 (2012), s. 3823-3833 ISSN 1520-6106 R&D Projects: GA ČR GAP205/10/0228; GA ČR GPP208/10/P398; GA ČR GA203/09/2037 Institutional research plan: CEZ:AV0Z40550506 Keywords : nucleic acids * phosphorus NMR * NMR calculations * cross-correlated relaxation * spin–spin coupling constants Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.607, year: 2012

  11. Interaction of abscisic acid with phospholipid membranes

    International Nuclear Information System (INIS)

    Stillwell, W.; Brengle, B.; Hester, P.; Wassall, S.T.

    1989-01-01

    The plant hormone abscisic acid (ABA) is shown, under certain conditions, to greatly enhance the permeability of phospholipid bilayer membranes to the nonelectrolyte erythritol (followed spectrophotometrically by osmotic swelling) and the anion carboxyfluorescein (followed by fluorescence). The hormone is ineffective with single- and mixed-component phosphatidylcholine membranes in the liquid-crystalline or gel states. In contrast, substantial ABA-induced permeability is measured for two-component membranes containing lipids with different polar head groups or containing phosphatidylcholines with different acyl chains at temperatures where gel and liquid-crystalline phases coexist. Despite the large ABA-induced enhancement in bilayer permeability, no evidence for a substantial change at the molecular level was seen in the membranes by magnetic resonance techniques. 13 C NMR spin-lattice relaxation times, T 1 , in sonicated unilamellar vesicles and ESR of spin-labeled fatty acids intercalated into membranes showed negligible effect on acyl chain order and dynamics within the bilayer, while 31 P NMR of sonicated unilamellar vesicles indicated negligible effect on molecular motion and conformation in the head-group region. The authors propose that, instead of causing a general nonspecific perturbation to the membrane, the hormone acts at membrane defects formed due to mismatch in molecular packing where two different head groups or acyl chain states interface. Increased membrane disruption by ABA at these points of membrane instability could then produce an enhancement in permeability

  12. A two-stage model for in vivo assessment of brain tumor perfusion and abnormal vascular structure using arterial spin labeling.

    Directory of Open Access Journals (Sweden)

    Patrick W Hales

    Full Text Available The ability to assess brain tumor perfusion and abnormalities in the vascular structure in vivo could provide significant benefits in terms of lesion diagnosis and assessment of treatment response. Arterial spin labeling (ASL has emerged as an increasingly viable methodology for non-invasive assessment of perfusion. Although kinetic models have been developed to describe perfusion in healthy tissue, the dynamic behaviour of the ASL signal in the brain tumor environment has not been extensively studied. We show here that dynamic ASL data acquired in brain tumors displays an increased level of 'biphasic' behaviour, compared to that seen in healthy tissue. A new two-stage model is presented which more accurately describes this behaviour, and provides measurements of perfusion, pre-capillary blood volume fraction and transit time, and capillary bolus arrival time. These biomarkers offer a novel contrast in the tumor and surrounding tissue, and provide a means for measuring tumor perfusion and vascular structural abnormalities in a fully non-invasive manner.

  13. The Effects of Acutely Administered 3,4-Methylenedioxymethamphetamine on Spontaneous Brain Function in Healthy Volunteers Measured with Arterial Spin Labeling and Blood Oxygen Level–Dependent Resting State Functional Connectivity

    Science.gov (United States)

    Carhart-Harris, Robin L.; Murphy, Kevin; Leech, Robert; Erritzoe, David; Wall, Matthew B.; Ferguson, Bart; Williams, Luke T.J.; Roseman, Leor; Brugger, Stefan; De Meer, Ineke; Tanner, Mark; Tyacke, Robin; Wolff, Kim; Sethi, Ajun; Bloomfield, Michael A.P.; Williams, Tim M.; Bolstridge, Mark; Stewart, Lorna; Morgan, Celia; Newbould, Rexford D.; Feilding, Amanda; Curran, H. Val; Nutt, David J.

    2015-01-01

    Background The compound 3,4-methylenedioxymethamphetamine (MDMA) is a potent monoamine releaser that produces an acute euphoria in most individuals. Methods In a double-blind, placebo-controlled, balanced-order study, MDMA was orally administered to 25 physically and mentally healthy individuals. Arterial spin labeling and seed-based resting state functional connectivity (RSFC) were used to produce spatial maps displaying changes in cerebral blood flow (CBF) and RSFC after MDMA administration. Participants underwent two arterial spin labeling and two blood oxygen level–dependent scans in a 90-minute scan session; MDMA and placebo study days were separated by 1 week. Results Marked increases in positive mood were produced by MDMA. Decreased CBF only was observed after MDMA, and this was localized to the right medial temporal lobe (MTL), thalamus, inferior visual cortex, and the somatosensory cortex. Decreased CBF in the right amygdala and hippocampus correlated with ratings of the intensity of global subjective effects of MDMA. The RSFC results complemented the CBF results, with decreases in RSFC between midline cortical regions, the medial prefrontal cortex, and MTL regions, and increases between the amygdala and hippocampus. There were trend-level correlations between these effects and ratings of intense and positive subjective effects. Conclusions The MTLs appear to be specifically implicated in the mechanism of action of MDMA, but further work is required to elucidate how the drug’s characteristic subjective effects arise from its modulation of spontaneous brain activity. PMID:24495461

  14. The Effects of Acutely Administered 3,4-Methylenedioxymethamphetamine on Spontaneous Brain Function in Healthy Volunteers Measured with Arterial Spin Labeling and Blood Oxygen Level-Dependent Resting State Functional Connectivity.

    Science.gov (United States)

    Carhart-Harris, Robin L; Murphy, Kevin; Leech, Robert; Erritzoe, David; Wall, Matthew B; Ferguson, Bart; Williams, Luke T J; Roseman, Leor; Brugger, Stefan; De Meer, Ineke; Tanner, Mark; Tyacke, Robin; Wolff, Kim; Sethi, Ajun; Bloomfield, Michael A P; Williams, Tim M; Bolstridge, Mark; Stewart, Lorna; Morgan, Celia; Newbould, Rexford D; Feilding, Amanda; Curran, H Val; Nutt, David J

    2015-10-15

    The compound 3,4-methylenedioxymethamphetamine (MDMA) is a potent monoamine releaser that produces an acute euphoria in most individuals. In a double-blind, placebo-controlled, balanced-order study, MDMA was orally administered to 25 physically and mentally healthy individuals. Arterial spin labeling and seed-based resting state functional connectivity (RSFC) were used to produce spatial maps displaying changes in cerebral blood flow (CBF) and RSFC after MDMA administration. Participants underwent two arterial spin labeling and two blood oxygen level-dependent scans in a 90-minute scan session; MDMA and placebo study days were separated by 1 week. Marked increases in positive mood were produced by MDMA. Decreased CBF only was observed after MDMA, and this was localized to the right medial temporal lobe (MTL), thalamus, inferior visual cortex, and the somatosensory cortex. Decreased CBF in the right amygdala and hippocampus correlated with ratings of the intensity of global subjective effects of MDMA. The RSFC results complemented the CBF results, with decreases in RSFC between midline cortical regions, the medial prefrontal cortex, and MTL regions, and increases between the amygdala and hippocampus. There were trend-level correlations between these effects and ratings of intense and positive subjective effects. The MTLs appear to be specifically implicated in the mechanism of action of MDMA, but further work is required to elucidate how the drug's characteristic subjective effects arise from its modulation of spontaneous brain activity. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  15. Stable isotope labeling strategy based on coding theory

    Energy Technology Data Exchange (ETDEWEB)

    Kasai, Takuma; Koshiba, Seizo; Yokoyama, Jun; Kigawa, Takanori, E-mail: kigawa@riken.jp [RIKEN Quantitative Biology Center (QBiC), Laboratory for Biomolecular Structure and Dynamics (Japan)

    2015-10-15

    We describe a strategy for stable isotope-aided protein nuclear magnetic resonance (NMR) analysis, called stable isotope encoding. The basic idea of this strategy is that amino-acid selective labeling can be considered as “encoding and decoding” processes, in which the information of amino acid type is encoded by the stable isotope labeling ratio of the corresponding residue and it is decoded by analyzing NMR spectra. According to the idea, the strategy can diminish the required number of labelled samples by increasing information content per sample, enabling discrimination of 19 kinds of non-proline amino acids with only three labeled samples. The idea also enables this strategy to combine with information technologies, such as error detection by check digit, to improve the robustness of analyses with low quality data. Stable isotope encoding will facilitate NMR analyses of proteins under non-ideal conditions, such as those in large complex systems, with low-solubility, and in living cells.

  16. Stable isotope labeling strategy based on coding theory

    International Nuclear Information System (INIS)

    Kasai, Takuma; Koshiba, Seizo; Yokoyama, Jun; Kigawa, Takanori

    2015-01-01

    We describe a strategy for stable isotope-aided protein nuclear magnetic resonance (NMR) analysis, called stable isotope encoding. The basic idea of this strategy is that amino-acid selective labeling can be considered as “encoding and decoding” processes, in which the information of amino acid type is encoded by the stable isotope labeling ratio of the corresponding residue and it is decoded by analyzing NMR spectra. According to the idea, the strategy can diminish the required number of labelled samples by increasing information content per sample, enabling discrimination of 19 kinds of non-proline amino acids with only three labeled samples. The idea also enables this strategy to combine with information technologies, such as error detection by check digit, to improve the robustness of analyses with low quality data. Stable isotope encoding will facilitate NMR analyses of proteins under non-ideal conditions, such as those in large complex systems, with low-solubility, and in living cells

  17. Synthesis of specifically labelled L-phenylalanines using phenylalanine ammonia lyase activity

    International Nuclear Information System (INIS)

    Haedener, A.; Tamm, Ch.

    1987-01-01

    Specifically labelled L-phenylalanines have been prepared using a variety of classical synthetic methods in combination with phenylalanine ammonia lyase (PAL) enzyme activity of the yeast Rhodosporidium toruloides ATCC 10788 or Rhodotorula glutinis IFO 0559, respectively. Thus, L-[2- 2 H]phenyl-[2- 2 H]alanine was formed from (E) -[2,2'- 2 H 2 ]cinnamic acid and ammonia in 46% yield, whereas L-phenyl-[2- 13 C, 15 N]alanine was obtained from (E)-[2- 13 C]cinnamic acid in 45% overall yield. Generally, labelled cinnamic acids were recovered in pure form from the reaction mixture, with a loss of 6-8%. Likewise, unchanged 15 NH 3 was reisolated as 15 NH 4 Cl after steam distillation with overall losses of less than 4%. Labelled cinnamic acids were prepared by Knoevenagel condensations between appropriately labelled benzaldehydes and malonic acids. [2- 2 H]Benzaldehyde was obtained from 2-bromotoluene by decomposition of the corresponding Grignard reagent with 2 H 2 O and subsequent oxidation. Since simple molecules, most of them commercially available in labelled form or otherwise easily accessible, may serve as starting material, and due to its defined stereochemistry, the reaction catalysed by PAL opens a short and attractive route to specifically labelled L-phenylalanines. (author)

  18. Inhibition of carnitine-acyl transferase I by oxfenicine studied in vivo with [11C]-labeled fatty acids

    International Nuclear Information System (INIS)

    Angsten, Gertrud; Valind, Sven; Takalo, Reijo; Neu, Henrik; Meurling, Staffan; Langstroem, Bengt

    2005-01-01

    Methods: Anesthetized pigs were studied with [ 11 C]-labeled fatty acids (FAs) with carbon chain length ranging from 8 to 16 carbon atoms, during control conditions and during inhibition of carnitine-palmitoyl transferase I (CPT I) with oxfenicine. The myocardial uptake of [ 11 C]-FAs from blood was measured together with the relative distribution of [ 11 C]-acyl-CoA between rapid mitochondrial oxidation and incorporation into slow turnover lipid pools in the heart. Results: During baseline conditions, the fractional oxidative utilization of palmitate was almost as high as that of carnitine-independent short-chain FAs, unless the carnitine shuttle was inhibited by high levels of lactate. Inhibition of CPT I almost completely blocked the oxidative pathway for palmitic acid and reduced the fractional oxidative utilization, while the rate of oxidative metabolism of acyl-CoA was unaffected. Conclusions: [ 11 C]-Labeled FAs allow rapid oxidation to be well separated from esterification into slow turnover lipid pools in the heart of anaesthetized pigs. The fractional oxidative utilization of [ 11 C]-palmitate serves well to characterize, in vivo, the carnitine-dependent transfer of long-chain FAs

  19. Electron detachment dissociation of fluorescently labeled sialylated oligosaccharides.

    Science.gov (United States)

    Zhou, Wen; Håkansson, Kristina

    2011-12-01

    We explored the application of electron detachment dissociation (EDD) and infrared multiphoton dissociation (IRMPD) tandem mass spectrometry to fluorescently labeled sialylated oligosaccharides. Standard sialylated oligosaccharides and a sialylated N-linked glycan released from human transferrin were investigated. EDD yielded extensive glycosidic cleavages and cross-ring cleavages in all cases studied, consistently providing complementary structural information compared with infrared multiphoton dissociation. Neutral losses and satellite ions such as C-2H ions were also observed following EDD. In addition, we examined the influence of different fluorescent labels. The acidic label 2-aminobenzoic acid (2-AA) enhanced signal abundance in negative-ion mode. However, few cross-ring fragments were observed for 2-AA-labeled oligosaccharides. The neutral label 2-aminobenzamide (2-AB) resulted in more cross-ring cleavages compared with 2-AA-labeled species, but not as extensive fragmentation as for native oligosaccharides, likely resulting from altered negative charge locations from introduction of the fluorescent tag. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. WE-FG-206-05: New Arterial Spin Labeling Method for Simultaneous Estimation of Arterial Cerebral Blood Volume, Cerebral Blood Flow and Arterial Transit Time

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, M; Whitlow, C; Jung, Y [Wake Forest School of Medicine, Winston-Salem, NC (United States); Liu, H [UT MD Anderson Cancer Center, Houston, TX (United States)

    2016-06-15

    Purpose: To demonstrate the feasibility of a novel Arterial Spin Labeling (ASL) method for simultaneously measuring cerebral blood flow (CBF), arterial transit time (ATT), and arterial cerebral blood volume (aCBV) without the use of a contrast agent. Methods: A series of multi-TI ASL images were acquired from one healthy subject on a 3T Siemens Skyra, with the following parameters: PCASL labeling with variable TI [300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000, 2500, 3000, 3500, 4000] ms, labeling bolus 1400 ms when TI allows, otherwise 100 ms less than TI, TR was minimized for each TI, two sinc shaped pre-saturation pulses were applied in the imaging plane immediately before 2D EPI acquisition. 64×64×24 voxels, 5 mm slice thickness, 1 mm gap, full brain coverage, 6 averages per TI, no crusher gradients, 11 ms TE, scan time of 4:56. The perfusion weighted time-series was created for each voxel and fit to a novel model. The model has two components: 1) the traditional model developed by Buxton et al., accounting for CBF and ATT, and 2) a box car function characterizing the width of the labeling bolus, with variable timing and height in proportion to the aCBV. All three parameters were fit using a nonlinear fitting routine that constrained all parameters to be positive. The main purpose of the high-temporal resolution TI sampling for the first second of data acquisition was to precisely estimate the blood volume component for better detection of arrival time and magnitude of signal. Results: Whole brain maps of CBF, ATT, and aCBV were produced, and all three parameters maps are consistent with similar maps described in the literature. Conclusion: Simultaneous mapping of CBF, ATT, and aCBV is feasible with a clinically tractable scan time (under 5 minutes).

  1. Solid state nuclear magnetic resonance with magic-angle spinning and dynamic nuclear polarization below 25 K.

    Science.gov (United States)

    Thurber, Kent R; Potapov, Alexey; Yau, Wai-Ming; Tycko, Robert

    2013-01-01

    We describe an apparatus for solid state nuclear magnetic resonance (NMR) with dynamic nuclear polarization (DNP) and magic-angle spinning (MAS) at 20-25 K and 9.4 Tesla. The MAS NMR probe uses helium to cool the sample space and nitrogen gas for MAS drive and bearings, as described earlier, but also includes a corrugated waveguide for transmission of microwaves from below the probe to the sample. With a 30 mW circularly polarized microwave source at 264 GHz, MAS at 6.8 kHz, and 21 K sample temperature, greater than 25-fold enhancements of cross-polarized (13)C NMR signals are observed in spectra of frozen glycerol/water solutions containing the triradical dopant DOTOPA-TEMPO when microwaves are applied. As demonstrations, we present DNP-enhanced one-dimensional and two-dimensional (13)C MAS NMR spectra of frozen solutions of uniformly (13)C-labeled l-alanine and melittin, a 26-residue helical peptide that we have synthesized with four uniformly (13)C-labeled amino acids. Published by Elsevier Inc.

  2. Preparation and Adsorption Property of Imido-acetic Acid Type Chelating Nano-fibers by Electro-spinning Technique

    Science.gov (United States)

    Yang, Jiali; Lu, Lansi; Zhang, Zhu; Liao, Minhui; He, Huirong; Li, Lingxing; Chen, Jida; Chen, Shijin

    2017-12-01

    A novel nano-fibrous adsorbent from imino-acetic acid (IDA) and polyvinyl alcohol (PVA) mixture solution was prepared by electro-spinning technique. The nano-fibrous adsorbents with imino-acetic acid functional groups were characterized and demonstrated by fourier transform infrared spectrometry (FT-IR) and the scanning electron microscopy (SEM). The effect of the adsorbents to remove heavy metals such as lead (Pb) and copper (Cu) ions from the aqueous solution was studied. The maximum adsorption percentage (SP) of the metal ions can reach 93.08% for Cu (II) and 96.69% for Pb(II), respectively. Furthermore, it shows that the adsorption procedure of the adsorbents is spontaneous and endothermic, and adsorption rate fits well with pseudo-second-order kinetic model. Most importantly, the reusability of the nanofibers for removal of metal ions was also demonstrated to be used at least five times.

  3. Rhenium 188 labelling of peptide conjugates

    International Nuclear Information System (INIS)

    Melendez-Alafort, Laura

    2001-01-01

    Many human tumours express high levels, of somatostatin receptors. In order to make possible a radiotherapeutic treatment of this kind for tumour a series of somatostatin analogues that can tightly chelate beta emitting isotopes have been developed in recent years. The work carried out for this thesis has been aimed towards development of a new therapeutic radiopharmaceutical for treatment of somatostatin receptor positive tumours. The first chapters describe work with technetium-99m to establish the labelling and analytical conditions for a somatostatin analogue, [Tyr 3 ]-octreotide (TOC), as a precursor to undertaking labelling studies with the beta emitter rhenium-188. 6-Hydrazinopyridine-3-carboxylic acid (HYNIC) was conjugated to TOC and labelled with 99m using different coligands. Then the stability, receptor binding and biodistribution of each complex were assessed. 99m Tc-HYNIC-TOC using EDDA as coligand showed the best characteristics, and was superior for tumour imaging in humans than the commercially available 111 In-DTPA-octreotide. The conditions for labelling the HYNIC-TOC conjugate with 188 Re were then optimised using tricine as a co-ligand. A labelling yield of ∼80% was achieved. After purification however, the stability of the complex was low. The use of other coligand systems which had proved useful for 99m Tc labelling was explored, but yields were very poor. Other chelators such as diethylenetriamine pentaacetic acid (DTPA), dimercaptosuccinic acid (DMSA) and mercaptoacetyltriglycine (MAG 3 ) were studied as potential co-ligand agents to label the HYNIC-TOC conjugate with 188 Re but, again low yields of the labelled peptide complexes were achieved. A novel 188 Re-HYNIC complex was prepared in high yields using N-N-disubstituted dithiocarbamates as coligands. However to date, the specific activities achieved with this system are relatively low. The use of the [ 99m Tc(CO) 3 (H 2 O) 3 ] complex to label the HYNIC-TOC conjugate was investigated

  4. Synthesis and preliminary evaluation of 18F-labeled 4-thia palmitate as a PET tracer of myocardial fatty acid oxidation

    International Nuclear Information System (INIS)

    DeGrado, Timothy R.; Wang Shuyan; Holden, James E.; Nickles, R. Jerome; Taylor, Michael; Stone, Charles K.

    2000-01-01

    Interest remains strong for the development of a noninvasive technique for assessment of regional fatty acid oxidation rate in the myocardium. 18 F-labeled 4-thia palmitate (FTP, 16-[ 18 F]fluoro-4-thia-hexadecanoic acid) has been synthesized and preliminarily evaluated as a metabolically trapped probe of myocardial fatty acid oxidation for positron emission tomography (PET). The radiotracer is synthesized by Kryptofix 2.2.2/K 2 CO 3 assisted nucleophilic radiofluorination of an iodo-ester precursor, followed by alkaline hydrolysis and by purification by reverse phase high performance liquid chromatography. Biodistribution studies in rats showed high uptake and long retention of FTP in heart, liver, and kidneys consistent with relatively high fatty acid oxidation rates in these tissues. Inhibition of carnitine palmitoyl-transferase-I caused an 80% reduction in myocardial uptake, suggesting the dependence of trapping on the transport of tracer into the mitochondrion. Experiments with perfused rat hearts showed that the estimates of the fractional metabolic trapping rate (FR) of FTP tracked inhibition of oxidation rate of palmitate with hypoxia, whereas the FR of the 6-thia analog 17-[ 18 F]fluoro-6-thia-heptadecanoic acid was insensitive to hypoxia. In vivo defluorination of FTP in the rat was evidenced by bone uptake of radioactivity. A PET imaging study with FTP in normal swine showed excellent myocardial images, prolonged myocardial retention, and no bone uptake of radioactivity up to 3 h, the last finding suggesting a species dependence for defluorination of the omega-labeled fatty acid. The results support further investigation of FTP as a potential PET tracer for assessing regional fatty acid oxidation rate in the human myocardium

  5. Site-selective 13C labeling of proteins using erythrose

    International Nuclear Information System (INIS)

    Weininger, Ulrich

    2017-01-01

    NMR-spectroscopy enables unique experimental studies on protein dynamics at atomic resolution. In order to obtain a full atom view on protein dynamics, and to study specific local processes like ring-flips, proton-transfer, or tautomerization, one has to perform studies on amino-acid side chains. A key requirement for these studies is site-selective labeling with 13 C and/or 1 H, which is achieved in the most general way by using site-selectively 13 C-enriched glucose (1- and 2- 13 C) as the carbon source in bacterial expression systems. Using this strategy, multiple sites in side chains, including aromatics, become site-selectively labeled and suitable for relaxation studies. Here we systematically investigate the use of site-selectively 13 C-enriched erythrose (1-, 2-, 3- and 4- 13 C) as a suitable precursor for 13 C labeled aromatic side chains. We quantify 13 C incorporation in nearly all sites in all 20 amino acids and compare the results to glucose based labeling. In general the erythrose approach results in more selective labeling. While there is only a minor gain for phenylalanine and tyrosine side-chains, the 13 C incorporation level for tryptophan is at least doubled. Additionally, the Phe ζ and Trp η2 positions become labeled. In the aliphatic side chains, labeling using erythrose yields isolated 13 C labels for certain positions, like Ile β and His β, making these sites suitable for dynamics studies. Using erythrose instead of glucose as a source for site-selective 13 C labeling enables unique or superior labeling for certain positions and is thereby expanding the toolbox for customized isotope labeling of amino-acid side-chains.

  6. The rabbit biodistribution of a therapeutic dose of zoledronic acid labeled with Tc-99m

    International Nuclear Information System (INIS)

    Asikoglu, Makbule; Gamze Durak, Funda

    2009-01-01

    The aim of the present study was to label a therapeutic dose of zoledronic acid (ZOL) with Tc-99m, evaluate its in vitro stability and compare its biodistribution to 99m Tc-methylene biphosphonate ( 99m Tc-MDP) in normal rabbits. Preparation of 0.50 mg of 99m Tc-ZOL was carried out by the reduction of 99m Tc-pertechnetate in the presence of stannous chloride. The radiolabeling efficiency was found to be greater than 99%. The labeled complex was stable at least up to 6 h at room temperature determined by paper chromatography. 99m Tc-ZOL and 99m Tc-MDP were administered intravenously to the rabbits for scintigraphic studies. Between 99m Tc-ZOL and 99m Tc-MDP, there were no significant differences in the ratios of femur/BG and lumbar vertebrae/BG, whereas epiphysis/BG and the kidney/BG ratios of 99m Tc-MDP were higher than 99m Tc-ZOL at the static studies.

  7. Preparation of 188Re labelled antibodies

    International Nuclear Information System (INIS)

    Zhu Minghua; Cao Rongzhen; Li Wenxin; Sheng Rong; Yin Duanzhi; He Weiyu; Zhou Wei; Wang Yongxian

    1998-01-01

    A simple technique of directly labelling antibodies with 188 Re has been developed. The reduction of antibody disulfide groups was achieved by incubation of antibody with ascorbic acid (pH = 6.5) for an hour at room temperature and a solution of excess SnCl 2 in sodium gluconate was added to the AA-reduced antibody followed by the addition of perrhenate. Some factors that influence labelling efficiency, such as the pH of the reaction mixture, the labelling time, and the amount of antibodies and reductive agent, were studied experimentally and a better labelling method was established. The labelling yields, as determined by paper chromatography, were greater than 80%

  8. Custom synthesis of isotope-labelled Apis mellifera Pheromone

    International Nuclear Information System (INIS)

    Conanan, Aida P.; Cortes, Nicole Marie A.; Daguno, Cristel Lyn R.; Templonuevo, Jose Angelo A.; Sucgang, Raymond J.

    2012-01-01

    The object of this study is to determine the optimum conditions for the synthesis of the isotope-labelled isopentyl acetate. Isopentyl acetate is widely used as a raw material in industries, in syntheses, and is utilized as a sex attractant (pheromone) by the bee species, Apis mellifera. The isotope labelling of isopentyl acetate will allow tracking of the fate and movement of the isopentyl acetate in the environment, in chemical transformations, and in biological systems. Esterification by alcoholysis of acetic acid was optimized for the preparation of Carbon-14( 14 C)-labelled isopentyl acetate from 14 C-labelled acetic acid and isoamyl alcohol. The different conditions studied were: (1) The effects of acid catalysis and/or reflux on the incorporation and retention of the isotope label on the product. The efficiency of label incorporation and retention was determined through the beta radioactivity of Carbon 14 in each of the synthetic constructs. Determination of the beta radioactivity concentration of 14 C in the isopentyl acetate product was done using low level liquid scintillation spectrometry. Each of the synthetic products was mixed with Ultima Gold scintillation cocktail in a low potassium glass scintillation vial, and analysed in a low-level Wallac 1414 scintillation counter. The application of catalysis without reflux resulted in the highest yield (35%). The same condition also resulted in the highest abundance of carbon isotope label with 2.40 Bequerels per cubic centimetre, Bq/cc (measurement unit for radioactivity). (author)

  9. Optimization of transversal relaxation of nitroxides for pulsed electron-electron double resonance spectroscopy in phospholipid membranes.

    Science.gov (United States)

    Dastvan, Reza; Bode, Bela E; Karuppiah, Muruga Poopathi Raja; Marko, Andriy; Lyubenova, Sevdalina; Schwalbe, Harald; Prisner, Thomas F

    2010-10-28

    Pulsed electron-electron double resonance (PELDOR) spectroscopy is increasingly applied to spin-labeled membrane proteins. However, after reconstitution into liposomes, spin labels often exhibit a much faster transversal relaxation (T(m)) than in detergent micelles, thus limiting application of the method in lipid bilayers. In this study, the main reasons for enhanced transversal relaxation in phospholipid membranes were investigated systematically by use of spin-labeled derivatives of stearic acid and phosphatidylcholine as well as spin-labeled derivatives of the channel-forming peptide gramicidin A under the conditions typically employed for PELDOR distance measurements. Our results clearly show that dephasing due to instantaneous diffusion that depends on dipolar interaction among electron spins is an important contributor to the fast echo decay in cases of high local concentrations of spin labels in membranes. The main difference between spin labels in detergent micelles and membranes is their local concentration. Consequently, avoiding spin clustering and suppressing instantaneous diffusion is the key step for maximizing PELDOR sensitivity in lipid membranes. Even though proton spin diffusion is an important relaxation mechanism, only in samples of low local concentrations does deuteration of acyl chains and buffer significantly prolong T(m). In these cases, values of up to 7 μs have been achieved. Furthermore, our study revealed that membrane composition and labeling position in the membrane can also affect T(m), either by promoting the segregation of spin-labeled species or by altering their exposure to matrix protons. Effects of other experimental parameters including temperature (<50 K), presence of oxygen, and cryoprotectant type are negligible under our experimental conditions.

  10. Biogeochemical processes of incorporation and transformation of 14C labelled fulvic acid, humic acid and simple organic molecules at the sediment-water interface (submarine canyon of the NW Mediterranean)

    International Nuclear Information System (INIS)

    Buscail, R.; Gadel, F.

    1987-01-01

    The input of organic compounds at the marine water-sediment interface was simulated by the injection of 14 C labelled raygrass fulvic and humic acids and glutamic acid in the overlying water of three identically preserved interfaces. After incubations of 6 days under in situ conditions (13 0 C, oxidizing conditions), separation of the resulting products are carried out by successive chemical extractions. They correspond to the relative importance of biological (respiration, assimilation) and geochemical (condensation in geopolymers and adsorption) processes. Two experiments have showed predominance of biological processes (with 14 C fulvic and glutamic acids), while in the case of 14 C humic acid, incorporation in sediment and geochemical processes are more important. (Auth.)

  11. Diffusion studies on permeable nitroxyl spin probes through bilayer lipid membranes: A low frequency ESR study

    International Nuclear Information System (INIS)

    Meenakumari, V.; Benial, A. Milton Franklin; Utsumi, Hideo; Ichikawa, Kazuhiro; Yamada, Ken-ichi; Hyodo, Fuminori; Jawahar, A.

    2015-01-01

    Electron spin resonance (ESR) studies were carried out for permeable 2mM 14 N-labeled deutrated 3 Methoxy carbonyl-2,2,5,5-tetramethyl-pyrrolidine-1-oxyl (MC-PROXYL) in pure water and 1mM, 2mM, 3mM, 4mM concentration of 14N-labeled deutrated MC-PROXYL in 400mM concentration of liposomal solution by using a 300 MHz ESR spectrometer. The ESR parameters such as linewidth, hyperfine coupling constant, g-factor, partition parameter and permeability were reported for these samples. The line broadening was observed for the nitroxyl spin probe in the liposomal solution. The line broadening indicates that the high viscous nature of the liposomal solution. The partition parameter and permeability values indicate the maximum diffusion of nitroxyl spin probes in the bilayer lipid membranes at 2 mM concentration of nitroxyl radical. This study illustrates that ESR can be used to differentiate between the intra and extra- membrane water by loading the liposome vesicles with a lipid-permeable nitroxyl spin probe. From the ESR results, the spin probe concentration was optimized as 2mM in liposomal solution for ESR phantom studies/imaging, invivo and invitro experiments

  12. Intrinsically Labeled Fluorescent Oligonucleotide Probes on Quantum Dots for Transduction of Nucleic Acid Hybridization.

    Science.gov (United States)

    Shahmuradyan, Anna; Krull, Ulrich J

    2016-03-15

    Quantum dots (QDs) have been widely used in chemical and biosensing due to their unique photoelectrical properties and are well suited as donors in fluorescence resonance energy transfer (FRET). Selective hybridization interactions of oligonucleotides on QDs have been determined by FRET. Typically, the QD-FRET constructs have made use of labeled targets or have implemented labeled sandwich format assays to introduce dyes in proximity to the QDs for the FRET process. The intention of this new work is to explore a method to incorporate the acceptor dye into the probe molecule. Thiazole orange (TO) derivatives are fluorescent intercalating dyes that have been used for detection of double-stranded nucleic acids. One such dye system has been reported in which single-stranded oligonucleotide probes were doubly labeled with adjacent thiazole orange derivatives. In the absence of the fully complementary (FC) oligonucleotide target, the dyes form an H-aggregate, which results in quenching of fluorescence emission due to excitonic interactions between the dyes. The hybridization of the FC target to the probe provides for dissociation of the aggregate as the dyes intercalate into the double stranded duplex, resulting in increased fluorescence. This work reports investigation of the dependence of the ratiometric signal on the type of linkage used to conjugate the dyes to the probe, the location of the dye along the length of the probe, and the distance between adjacent dye molecules. The limit of detection for 34mer and 90mer targets was found to be identical and was 10 nM (2 pmol), similar to analogous QD-FRET using labeled oligonucleotide target. The detection system could discriminate a one base pair mismatch (1BPM) target and was functional without substantial compromise of the signal in 75% serum. The 1BPM was found to reduce background signal, indicating that the structure of the mismatch affected the environment of the intercalating dyes.

  13. Introduction to Spin Label Electron Paramagnetic Resonance Spectroscopy of Proteins

    Science.gov (United States)

    Melanson, Michelle; Sood, Abha; Torok, Fanni; Torok, Marianna

    2013-01-01

    An undergraduate laboratory exercise is described to demonstrate the biochemical applications of electron paramagnetic resonance (EPR) spectroscopy. The beta93 cysteine residue of hemoglobin is labeled by the covalent binding of 3-maleimido-proxyl (5-MSL) and 2,2,5,5-tetramethyl-1-oxyl-3-methyl methanethiosulfonate (MTSL), respectively. The excess…

  14. Isotopically labelled pyrimidines and purines

    International Nuclear Information System (INIS)

    Balaban, A.T.; Bally, I.

    1987-01-01

    Among the three diazines, pyrimidine is by far the most important one because its derivatives uracil, thymine and cytosine are constituents of the ubiquitous deoxynucleic acids (DNA) and ribonucleic acids (RNA). Other derivatives of pyrimidine without condensed rings include barbiturates, alloxan, orotic acid and thiamine or vitamin B 1 . From the polycyclic derivatives of pyrimidine such as pteridine, alloxazine, and purine, the latter, through its derivatives adenine and guanine complete the list of bases which occur in DNA and RNA: in addition, other purine derivatives such as hypoxanthine, xanthine, theobromine, theophylline, caffeine and uric acid are important natural products with biological activity. The paper presents methods for preparing isotopically labeled pyrimidines as well as purine derivatives. For convenience, the authors describe separately carbon-labeled with radioisotopes 11 C (T 1/2 = 20.3 min) and 14 C (T 1/2 = 5736 years) or the stable isotope 13 C (natural abundance 1.1%) and then hydrogen-labeled systems with the radioisotope 3 H ≡ T (T 1/2 = 12.346 years) or with the stable isotope 2 H ≡ D (natural abundance 0.015%). We do not separate stable from radioactive isotopes because the synthetic methods are identical for the same element; however, the introduction of hydrogen isotopes into organic molecules is often performed by reactions such as isotope exchange which cannot take place in the case of carbon isotopes

  15. Dynamics of the amino acid and protein metabolism of laying hens after the application of 15N-labelled wheat protein. 10

    International Nuclear Information System (INIS)

    Gruhn, K.; Hennig, A.

    1989-01-01

    Over a period of 4 days 12 colostomized laying hens daily received 36 g coarse wheat meal containing 14.37 atom-% 15 N excess ( 15 N') together with a conventional ration. After the homogenisation of each oviduct N and 15 N' were determined. After the precipitation with TCA the 15 N' of the amino acids was analysed in both the precipitate and the supernatant. In addition, the free amino acids and the peptides were determined in the TCA soluble fraction. The atom-% 15 N' in the total N and in the non-basic amino acid N showed a parallel decrease; it diminshed from 1.75 atom-% 15 N' to 0.64. Of the three basic amino acids, lysine shows the lowest labelling at all four measuring points. The quotas of non-basic amino acid 14 N and 15 N' in the total 14 N and 15 N' of the oviduct are the same and amount to 53%. In contrast to this, the quota of the 14 N of the basic amino acids in the total 14 N of the oviduct only amounts to 21.6% and that of 15 N' only to 15.4%. The average atom-% 15 N' of the free amino acids 12 h after the last 15 N application is 1.54 and is considerably above that of the peptides with 1.15 atom-% 15 N'. 36 h after the last 15 N application the ascertained value of 1.25 is identical in both fractions. The labelling of the free amino acids decreases more quickly than that of the peptides the more time has passed after the last 15 N application. (author)

  16. Exploring the dynamics about the glass transition by muon spin relaxation and muon spin rotation

    International Nuclear Information System (INIS)

    Bermejo, F J; Bustinduy, I; Cox, S F J; Lord, J S; Cabrillo, C; Gonzalez, M A

    2006-01-01

    The capability of muon spin rotation and muon spin relaxation to explore dynamics in the vicinity of the glass transition is illustrated by results pertaining to three materials exhibiting two different glass-forming abilities. Measurements under transverse magnetic fields enable us to monitor the dynamics of muonium-labelled closed-shell molecules within the microsecond range. The results display the onset of stochastic molecular motions taking place upon crossing from below the glass-transition temperature. In turn, the molecular dynamics of radicals formed by addition of atomic muonium to unsaturated organic molecules can also be explored up to far shorter times by means of relaxation measurements under longitudinal fields. The technique is then shown to be capable of singling out stochastic reorientational motions from others, which usually are strongly coupled to them and usually dominate the material response when measured using higher-frequency probes such as neutron and light scattering

  17. Efficacy of Folic Acid Supplementation in Autistic Children Participating in Structured Teaching: An Open-Label Trial.

    Science.gov (United States)

    Sun, Caihong; Zou, Mingyang; Zhao, Dong; Xia, Wei; Wu, Lijie

    2016-06-07

    Autism spectrum disorders (ASD) are recognized as a major public health issue. Here, we evaluated the effects of folic acid intervention on methylation cycles and oxidative stress in autistic children enrolled in structured teaching. Sixty-six autistic children enrolled in this open-label trial and participated in three months of structured teaching. Forty-four children were treated with 400 μg folic acid (two times/daily) for a period of three months during their structured teaching (intervention group), while the remaining 22 children were not given any supplement for the duration of the study (control group). The Autism Treatment Evaluation Checklist (ATEC) and Psychoeducational Profile-third edition (PEP-3) were measured at the beginning and end of the treatment period. Folic acid, homocysteine, and glutathione metabolism in plasma were measured before and after treatment in 29 autistic children randomly selected from the intervention group and were compared with 29 age-matched unaffected children (typical developmental group). The results illustrated folic acid intervention improved autism symptoms towards sociability, cognitive verbal/preverbal, receptive language, and affective expression and communication. Furthermore, this treatment also improved the concentrations of folic acid, homocysteine, and normalized glutathione redox metabolism. Folic acid supplementation may have a certain role in the treatment of children with autism.

  18. [(64) Cu]-labelled trastuzumab: optimisation of labelling by DOTA and NODAGA conjugation and initial evaluation in mice.

    Science.gov (United States)

    Schjoeth-Eskesen, Christina; Nielsen, Carsten Haagen; Heissel, Søren; Højrup, Peter; Hansen, Paul Robert; Gillings, Nic; Kjaer, Andreas

    2015-05-30

    The human epidermal growth factor receptor-2 (HER2) is overexpressed in 20-30% of all breast cancer cases, leading to increased cell proliferation, growth and migration. The monoclonal antibody, trastuzumab, binds to HER2 and is used for treatment of HER2-positive breast cancer. Trastuzumab has previously been labelled with copper-64 by conjugation of a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelator. The aim of this study was to optimise the (64) Cu-labelling of DOTA-trastuzumab and as the first to produce and compare with its 1,4,7-triazacyclononane, 1-glutaric acid-5,7 acetic acid (NODAGA) analogue in a preliminary HER2 tumour mouse model. The chelators were conjugated to trastuzumab using the activated esters DOTA mono-N-hydroxysuccinimide (NHS) and NODAGA-NHS. (64) Cu-labelling of DOTA-trastuzumab was studied by varying the amount of DOTA-trastuzumab used, reaction temperature and time. Full (64) Cu incorporation could be achieved using a minimum of 10-µg DOTA-trastuzumab, but the fastest labelling was obtained after 15 min at room temperature using 25 µg of DOTA-trastuzumab. In comparison, 80% incorporation was achieved for (64) Cu-labelling of NODAGA-trastuzumab. Both [(64) Cu]DOTA-trastuzumab and [(64) Cu]NODAGA-trastuzumab were produced after purification with radiochemical purities of >97%. The tracers were injected into mice with HER2 expressing tumours. The mice were imaged by positron emission tomography and showed high tumour uptake of 3-9% ID/g for both tracers. © 2015 The Authors Journal of Labelled Compounds and Radiopharmaceuticals published by John Wiley & Sons Ltd.

  19. Arterial spin labeling MR imaging for characterisation of renal masses in patients with impaired renal function: initial experience

    International Nuclear Information System (INIS)

    Pedrosa, Ivan; Rafatzand, Khashayar; Robson, Philip; Alsop, David C.; Wagner, Andrew A.; Atkins, Michael B.; Rofsky, Neil M.

    2012-01-01

    To retrospectively evaluate the feasibility of arterial spin labeling (ASL) magnetic resonance imaging (MRI) for the assessment of vascularity of renal masses in patients with impaired renal function. Between May 2007 and November 2008, 11/67 consecutive patients referred for MRI evaluation of a renal mass underwent unenhanced ASL-MRI due to moderate-to-severe chronic or acute renal failure. Mean blood flow in vascularised and non-vascularised lesions and the relation between blood flow and final diagnosis of malignancy were correlated with a 2-sided homogeneous variance t-test and the Fisher Exact Test, respectively. A p value 2 (range 7-39). The average blood flow of 11 renal masses interpreted as ASL-positive (134 +/- 85.7 mL/100 g/min) was higher than that of 6 renal masses interpreted as ASL-negative (20.5 +/- 8.1 mL/100 g/min)(p = 0.015). ASL-positivity correlated with malignancy (n = 3) or epithelial atypia (n = 1) at histopathology or progression at follow up (n = 7). ASL detection of vascularity in renal masses in patients with impaired renal function is feasible and seems to indicate neoplasia although the technique requires further evaluation. (orig.)

  20. Isotope-labelled folic acid derivatives

    International Nuclear Information System (INIS)

    Lewin, N.; Wong, E.T.

    1976-01-01

    The suggestion deals with the production of folic acid derivatives suitable as indicators or tracers for analyses of serum folates. These folic acid derivatives contain folic acid which is bound by one or both carboxyl groups to the amino nitrogen of compounds such as, e.g., tyramine, glycyl tyrosine, tyrosine, or the methyl ester of tyrosine. The derivative obtained can be substituted by a gamma emitter, e.g. the iodine isotope I 125. The radioactive derivative is used in the method for the competitive protein bonding to determine endogenic folates in the serum. (UWI) [de

  1. Synthesis of specifically labelled L-phenylalanines using phenylalanine ammonia lyase activity

    Energy Technology Data Exchange (ETDEWEB)

    Haedener, A.; Tamm, Ch.

    1987-11-01

    Specifically labelled L-phenylalanines have been prepared using a variety of classical synthetic methods in combination with phenylalanine ammonia lyase (PAL) enzyme activity of the yeast Rhodosporidium toruloides ATCC 10788 or Rhodotorula glutinis IFO 0559, respectively. Thus, L-(2-/sup 2/H)phenyl-(2-/sup 2/H)alanine was formed from (E) -(2,2'-/sup 2/H/sub 2/)cinnamic acid and ammonia in 46% yield, whereas L-phenyl-(2-/sup 13/C, /sup 15/N)alanine was obtained from (E)-(2-/sup 13/C)cinnamic acid in 45% overall yield. Generally, labelled cinnamic acids were recovered in pure form from the reaction mixture, with a loss of 6-8%. Likewise, unchanged /sup 15/NH/sub 3/ was reisolated as /sup 15/NH/sub 4/Cl after steam distillation with overall losses of less than 4%. Labelled cinnamic acids were prepared by Knoevenagel condensations between appropriately labelled benzaldehydes and malonic acids. (2-/sup 2/H)Benzaldehyde was obtained from 2-bromotoluene by decomposition of the corresponding Grignard reagent with /sup 2/H/sub 2/O and subsequent oxidation. Since simple molecules, most of them commercially available in labelled form or otherwise easily accessible, may serve as starting material, and due to its defined stereochemistry, the reaction catalysed by PAL opens a short and attractive route to specifically labelled L-phenylalanines.

  2. 99mTC-dextran-antibody conjugates. Labelling procedures

    International Nuclear Information System (INIS)

    Marquez, M.; Westlin, J.E.; Nilsson, S.; Holmberg, A.R.

    1996-01-01

    Dextran forms stable chelates with 99m Tc, a radionuclide with ideal properties for planar scintigraphic and tomographic imaging. This study investigates some of the factors of importance to the formation of 99m Tc-dextran. The complex was used for the technetium labelling of a monoclonal antibody. Two radiolabelling methods were studied: Direct dextran labelling with the reductant dissolved in HCl and labelling via a weak 'transfer' chelator (tartaric acid) with the reductant dissolved in ethanol. Different conditions during the labelling reaction were studied. Finally, dextran was coupled to a monoclonal anticytokeratin antibody and the conjugate was subsequently radiolabelled with 99m Tc. Gel filtration (GFR) and thin layer chromatography (TLC) were compared as methods for estimation of the labelling efficiency. When using 10-500 μM of ligand, 5-100 μM SnC1 2 with 10-500 MBq of technetium at pH7 incubated for 10-15 min, the radiolabelling seemed optimal (70-75% labelling efficiency). It was found that 100 μM tartaric acid used as a weak intermediate chelator with SnCl 2 dissolved in ethanol improved the reproducibility of the labelling. The labelling efficiency was not affected by either the presence of oxygen or the addition of an oxygen scavenger during the labelling incubation. In general, TLC showed higher labelling efficiencies than GFR, indicating inadequate separation of the different moieties. (orig.)

  3. Evaluation of Renal Blood Flow in Chronic Kidney Disease Using Arterial Spin Labeling Perfusion Magnetic Resonance Imaging.

    Science.gov (United States)

    Li, Lu-Ping; Tan, Huan; Thacker, Jon M; Li, Wei; Zhou, Ying; Kohn, Orly; Sprague, Stuart M; Prasad, Pottumarthi V

    2017-01-01

    Chronic kidney disease (CKD) is known to be associated with reduced renal blood flow. However, data to-date in humans is limited. In this study, non-invasive arterial spin labeling (ASL) MRI data was acquired in 33 patients with diabetes and stage-3 CKD, and 30 healthy controls. A significantly lower renal blood flow both in cortex (108.4±36.4 vs . 207.3±41.8; pblood flow were correlated with eGFR, and cortical blood flow was found to be confounded by age and BMI. However, in a subset of subjects that were matched for age and BMI (n=6), the differences between CKD and control subjects remained significant both in cortex (107.4±42.8 vs . 187.51±20.44; p=0.002) and medulla (15.43±8.43 vs . 39.18±11.13; p=0.002). A threshold value to separate healthy and CKD was estimated to be Cor_BF=142.9 and Med_BF=24.1. These results support the use of ASL in the evaluation of renal blood flow in patients with moderate level of CKD. Whether these measurements can identify subjects at risk of progressive CKD requires further longitudinal follow-up.

  4. Early-stage differentiation between presenile Alzheimer's disease and frontotemporal dementia using arterial spin labeling MRI

    Energy Technology Data Exchange (ETDEWEB)

    Steketee, Rebecca M.E.; Meijboom, Rozanna; Lugt, Aad van der; Smits, Marion [Erasmus MC - University Medical Center, Department of Radiology, PO Box 2040, Rotterdam (Netherlands); Bron, Esther E.; Klein, Stefan [Erasmus MC - University Medical Center, Biomedical Imaging Group Rotterdam, Departments of Medical Informatics and Radiology, PO Box 2040, Rotterdam (Netherlands); Houston, Gavin C. [GE Healthcare, Hatfield (United Kingdom); Mutsaerts, Henri J.M.M. [Academic Medical Center, Department of Radiology, PO Box 22660, Amsterdam (Netherlands); Mendez Orellana, Carolina P. [Erasmus MC - University Medical Center, Department of Radiology, PO Box 2040, Rotterdam (Netherlands); Erasmus MC - University Medical Center, Department of Neurology, PO Box 2040, Rotterdam (Netherlands); Jong, Frank Jan de; Swieten, John C. van [Erasmus MC - University Medical Center, Department of Neurology, PO Box 2040, Rotterdam (Netherlands)

    2016-01-15

    To investigate arterial spin labeling (ASL)-MRI for the early diagnosis of and differentiation between the two most common types of presenile dementia: Alzheimer's disease (AD) and frontotemporal dementia (FTD), and for distinguishing age-related from pathological perfusion changes. Thirteen AD and 19 FTD patients, and 25 age-matched older and 22 younger controls underwent 3D pseudo-continuous ASL-MRI at 3 T. Gray matter (GM) volume and cerebral blood flow (CBF), corrected for partial volume effects, were quantified in the entire supratentorial cortex and in 10 GM regions. Sensitivity, specificity and diagnostic performance were evaluated in regions showing significant CBF differences between patient groups or between patients and older controls. AD compared with FTD patients had hypoperfusion in the posterior cingulate cortex, differentiating these with a diagnostic performance of 74 %. Compared to older controls, FTD patients showed hypoperfusion in the anterior cingulate cortex, whereas AD patients showed a more widespread regional hypoperfusion as well as atrophy. Regional atrophy was not different between AD and FTD. Diagnostic performance of ASL to differentiate AD or FTD from controls was good (78-85 %). Older controls showed global hypoperfusion compared to young controls. ASL-MRI contributes to early diagnosis of and differentiation between presenile AD and FTD. (orig.)

  5. Early-stage differentiation between presenile Alzheimer's disease and frontotemporal dementia using arterial spin labeling MRI

    International Nuclear Information System (INIS)

    Steketee, Rebecca M.E.; Meijboom, Rozanna; Lugt, Aad van der; Smits, Marion; Bron, Esther E.; Klein, Stefan; Houston, Gavin C.; Mutsaerts, Henri J.M.M.; Mendez Orellana, Carolina P.; Jong, Frank Jan de; Swieten, John C. van

    2016-01-01

    To investigate arterial spin labeling (ASL)-MRI for the early diagnosis of and differentiation between the two most common types of presenile dementia: Alzheimer's disease (AD) and frontotemporal dementia (FTD), and for distinguishing age-related from pathological perfusion changes. Thirteen AD and 19 FTD patients, and 25 age-matched older and 22 younger controls underwent 3D pseudo-continuous ASL-MRI at 3 T. Gray matter (GM) volume and cerebral blood flow (CBF), corrected for partial volume effects, were quantified in the entire supratentorial cortex and in 10 GM regions. Sensitivity, specificity and diagnostic performance were evaluated in regions showing significant CBF differences between patient groups or between patients and older controls. AD compared with FTD patients had hypoperfusion in the posterior cingulate cortex, differentiating these with a diagnostic performance of 74 %. Compared to older controls, FTD patients showed hypoperfusion in the anterior cingulate cortex, whereas AD patients showed a more widespread regional hypoperfusion as well as atrophy. Regional atrophy was not different between AD and FTD. Diagnostic performance of ASL to differentiate AD or FTD from controls was good (78-85 %). Older controls showed global hypoperfusion compared to young controls. ASL-MRI contributes to early diagnosis of and differentiation between presenile AD and FTD. (orig.)

  6. Dynamics of the amino acid and protein metabolism of laying hens after the application of 15N-labelled wheat protein. 11

    International Nuclear Information System (INIS)

    Gruhn, K.; Zander, R.

    1989-01-01

    Over a period of 4 days 12 colostomized laying hens daily received 36 g 15 N-labelled wheat with 15 N excess ( 15 N') of 14.37 atom-% together with a conventional feed mixture for laying hens. The labelling of the lysine N in the wheat was 13.58 atom-%, that of histidine N 14.38 and that of arginine 15 N' 13.63 atom-% 15 N'. Three hens each were butchered 12, 36, 60 and 108 h after the last 15 N' feeding. The first three hens did not receive any feed before being butchered. The following three hens each received the unlabelled feed ration for another 1, 2 or 4 days, resp., after the main period until they were butchered. The total of skeleton muscles, heart and stomach muscle (without inner skin) of each hen were combined into one sample, cut thinly, drenched with fluid nitrogen and pulverized. N, 15 N' and the basic and non-basic amino acids as well as their 15 N' were determined in the individual samples. In contrast to the organs, the proteins in the muscle tissue have a long half-life so that a slight decrease of atom-% 15 N' in the muscles could only be detected after 108 h. The 14 N and 15 N' quota of the non-basic amino acids in the total nitrogen of the muscles is 50 %. The 14 N quota of the basic amino acids is 30% and the 15 N' quota only 22.5% in the total muscle N. The heavy nitrogen of the free lysine in the TCA soluble N fraction is hardly detectable 36 h and 60 h after the last 15 N' supply and not at all after 108 h. In contrast to this, the other two free basic amino acids remain significantly higher labelled in dependence on the last butchering time. (author)

  7. Label-free direct surface-enhanced Raman scattering (SERS) of nucleic acids (Conference Presentation)

    Science.gov (United States)

    Guerrini, Luca; Morla-Folch, Judit; Gisbert-Quilis, Patricia; Xie, Hainan; Alvarez-Puebla, Ramon

    2016-03-01

    Recently, plasmonic-based biosensing has experienced an unprecedented level of attention, with a particular focus on the nucleic acid detection, offering efficient solutions to engineer simple, fast, highly sensitive sensing platforms while overcoming important limitations of PCR and microarray techniques. In the broad field of plasmonics, surface-enhanced Raman scattering (SERS) spectroscopy has arisen as a powerful analytical tool for detection and structural characterization of biomolecules. Today applications of SERS to nucleic acid analysis largely rely on indirect strategies, which have been demonstrated very effective for pure sensing purposes but completely dismiss the exquisite structural information provided by the direct acquisition of the biomolecular vibrational fingerprint. Contrarily, direct label-free SERS of nucleic acid shows an outstanding potential in terms of chemical-specific information which, however, remained largely unexpressed mainly because of the inherent poor spectral reproducibility and/or limited sensitivity. To address these limitations, we developed a fast and affordable high-throughput screening direct SERS method for gaining detailed genomic information on nucleic acids (DNA and RNA) and for the characterization and quantitative recognition of DNA interactions with exogenous agents. The simple strategy relies on the electrostatic adhesion of DNA/RNA onto positively-charged silver colloids that promotes the nanoparticle aggregation into stable clusters yielding intense and reproducible SERS spectra at picogram level (i.e. the analysis can be performed without the necessity of amplification steps thus providing realistic direct information of the nucleic acid in its native state). We anticipate this method to gain a vast impact and set of applications in different fields, including medical diagnostics, genomic screening, drug discovery, forensic science and even molecular electronics.

  8. The choice of label and measurement technique in tracer studies of body protein metabolism in man

    International Nuclear Information System (INIS)

    James, W.P.T.; Sender, P.M.; Garlick, P.J.; Waterlow, J.C.

    1975-01-01

    The turnover of non-serum proteins in man has had limited study despite the physiological importance of maintaining the balance between synthesis and breakdown of body proteins. Body protein is usually considered as a single pool and breakdown rates are often measured by monitoring excreted label at intervals after pulse labelling with radioactive or 15 N amino acids. No label has yet been used for measuring tissue protein breakdown in man which is free from the major problem of label re-utilization. All measurements of breakdown rates, eg. with 75 Se-selenomethionine, 15 N- or 14 C-glycine, give rate constants which are too low. The heterogeneity of body proteins also means that an estimate of the weighted average breakdown rate can only be obtained after following the excretion of isotope for a long period, perhaps of the order of 3-4 half-lives which, for man, would be 100 days after labelling. We therefore use infusions with either 14 C- or 15 N-labelled amino acids to measure breakdown and synthesis rates: these values are less affected by problems of protein heterogeneity. Single injection techniques are subject to more error than constant infusions of label because of the difficulty of defining the precursor activity. 15 N labelling need not be confined to essential amino acids if total protein rather than amino acid turnover is studied: the latter involves measurements of the labelled amino acid itself which is difficult with 15 N because of the small amounts of free amino acid nitrogen available. Carbon labelling of non-essential amino acids is unsuitable for studies of protein turnover and the choice of the position of the label on the molecule is important when labelled essential amino acids are employed. Short-term changes in protein metabolism are evaluated better with amino acids with a small pool size; the equilibration time in the excretory bicarbonate pool is also shorter than in the urea pool so that 15 N is less useful than carbon labelling. We

  9. Kinetic study of formic acid oxidation on Ti/IrO{sub 2} electrodes prepared using the spin coating deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Fierro, Stephane, E-mail: stephane.fierro@epfl.c [Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology, ISIC-EPFL, CH-1015 Lausanne (Switzerland); Comninellis, Christos [Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology, ISIC-EPFL, CH-1015 Lausanne (Switzerland)

    2010-09-30

    In the first part of this paper, IrO{sub 2} electrodes produced by thermal decomposition of H{sub 2}IrCl{sub 6} precursor were manufactured using the spin coating deposition technique, where centrifugal forces spread the precursor solution with simultaneous evaporation of the solvent on the rotating Ti substrate. It was found using this technique, that it is possible to obtain thin and uniform IrO{sub 2} coatings with controlled loadings. The influence of the concentration of iridium salt in the precursor solution (c{sub 0}) as well as the influence of the rotation speed at which the substrate spins ({omega}) on the IrO{sub 2} loading have been studied using voltammetric charge measurements. From these results, a simple relation has been proposed for the estimation of the IrO{sub 2} loading for a given c{sub 0} and {omega}. In the second part of this paper and from measurements performed using different IrO{sub 2} loadings and formic acid concentrations, the kinetic parameters of the oxidation of formic acid have been quantitatively determined using a model that involves the redox couple IrO{sub 3}/IrO{sub 2} as mediator of this reaction. Furthermore, using the kinetic parameters obtained together with the Nernst equation and the I-V curves of the supporting electrolyte (1 M HClO{sub 4}), theoretical I-V curves could be constructed for different concentrations of formic acid and different IrO{sub 2} loadings.

  10. Isotope enrichment by electron spin resonance transitions of the intermediate radical pair

    International Nuclear Information System (INIS)

    Okazaki, M.; Shiga, T.; Sakata, S.; Konaka, R.; Toriyama, K.

    1988-01-01

    Microwave effects on the spin adduct yield were observed in the photoreduction of menadione in micellar solutions with ordinary sodium dodecyl sulfate (SDS), deuterium-labeled SDS, and a mixture of them. A large isotope effect was found in the microwave modulation of the spin adduct yield, which is due to the ESR transitions of the transient radical pair in the reaction. It is demonstrated for the first time that the microwave field can be used to enrich one of the isotopes which coexist in the system

  11. Inhibition of carnitine-acyl transferase I by oxfenicine studied in vivo with [{sup 11}C]-labeled fatty acids

    Energy Technology Data Exchange (ETDEWEB)

    Angsten, Gertrud [Department of Pediatric Surgery, University Children' s Hospital, S-751 85 Uppsala (Sweden)]. E-mail: gertrud.angsten@surgsci.uu.se; Valind, Sven [Uppsala University PET Centre, Uppsala University, S-751 05 Uppsala (Sweden); Department of Clinical Physiology, University Hospital, S-751 85 Uppsala (Sweden); Takalo, Reijo [Uppsala University PET Centre, Uppsala University, S-751 05 Uppsala (Sweden); Department of Clinical Physiology, University Hospital, S-751 85 Uppsala (Sweden); Neu, Henrik [Uppsala University PET Centre, Uppsala University, S-751 05 Uppsala (Sweden); Department of Organic Chemistry, Uppsala University, S-751 24 Uppsala (Sweden); Meurling, Staffan [Department of Pediatric Surgery, University Children' s Hospital, S-751 85 Uppsala (Sweden); Langstroem, Bengt [Uppsala University PET Centre, Uppsala University, S-751 05 Uppsala (Sweden); Department of Organic Chemistry, Uppsala University, S-751 24 Uppsala (Sweden)

    2005-07-01

    Methods: Anesthetized pigs were studied with [{sup 11}C]-labeled fatty acids (FAs) with carbon chain length ranging from 8 to 16 carbon atoms, during control conditions and during inhibition of carnitine-palmitoyl transferase I (CPT I) with oxfenicine. The myocardial uptake of [{sup 11}C]-FAs from blood was measured together with the relative distribution of [{sup 11}C]-acyl-CoA between rapid mitochondrial oxidation and incorporation into slow turnover lipid pools in the heart. Results: During baseline conditions, the fractional oxidative utilization of palmitate was almost as high as that of carnitine-independent short-chain FAs, unless the carnitine shuttle was inhibited by high levels of lactate. Inhibition of CPT I almost completely blocked the oxidative pathway for palmitic acid and reduced the fractional oxidative utilization, while the rate of oxidative metabolism of acyl-CoA was unaffected. Conclusions: [{sup 11}C]-Labeled FAs allow rapid oxidation to be well separated from esterification into slow turnover lipid pools in the heart of anaesthetized pigs. The fractional oxidative utilization of [{sup 11}C]-palmitate serves well to characterize, in vivo, the carnitine-dependent transfer of long-chain FAs.

  12. The cerebral metabolism of amino acids and related metabolites as studied by 13C and 14C labelling

    International Nuclear Information System (INIS)

    Hassel, B.

    1995-11-01

    The present investigations show the feasibility of analyzing the cerebral metabolism of amino acids and related metabolites by 13 C-and 14 C-labelling using labelled acetate and glucose as markers for glial and neuronal metabolism, respectively. Using [ 13 C[acetate, it was shown that glial cells export ∼60% of their TCA cycle intermediates, mostly as glutamine, and that this glutamine is used by neurons partly as an energy reserve, and partly it is converted directly to glutamate and GABA. Using [ 13 C[glucose, the glial process or pyruvate carboxylation was shown to compensate fully for the loss of glutamine. The mechanism of action of two neurotoxins, fluorocitrate and 3-nitropropionate was elucidated. The latter toxin was shown to inhibit the TCA cycle of GABAergic neurons selectively. Formation of pyruvate and lactate from glial TCA cycle intermediates was demonstrated in vivo. This pathway may be important for glial inactivation of transmitter glutamate and GABA. The results illustrate glianeuronal interactions, and they suggest the applicability of 13 CNMR spectroscopy to the detailed study of the cerebral metabolism of amino acids in the intact, unanesthetized human brain. 174 refs

  13. Electron Detachment Dissociation (EDD) of Fluorescently Labeled Sialylated Oligosaccharides

    Science.gov (United States)

    Zhou, Wen; Håkansson, Kristina

    2012-01-01

    We explored the application of electron detachment dissociation (EDD) and infrared multiphoton dissociation (IRMPD) tandem mass spectrometry to fluorescently labeled sialylated oligosaccharides. Standard sialylated oligosaccharides and a sialylated N-linked glycan released from human transferrin were investigated. EDD yielded extensive glycosidic cleavages and cross-ring cleavages in all cases studied, consistently providing complementary structural information compared to IRMPD. Neutral losses and satellite ions such as C – 2H ions were also observed following EDD. In addition, we examined the influence of different fluorescent labels. The acidic label 2-aminobenzoic acid (2-AA) enhanced signal abundance in negative-ion mode. However, few cross-ring fragments were observed for 2-AA labeled oligosaccharides. The neutral label 2-aminobenzamide (2-AB) resulted in more cross-ring cleavages compared to 2-AA labeled species, but not as extensive fragmentation as for native oligosaccharides, likely resulting from altered negative charge locations from introduction of the fluorescent tag. PMID:22120881

  14. Entangled spins and ghost-spins

    Directory of Open Access Journals (Sweden)

    Dileep P. Jatkar

    2017-09-01

    Full Text Available We study patterns of quantum entanglement in systems of spins and ghost-spins regarding them as simple quantum mechanical toy models for theories containing negative norm states. We define a single ghost-spin as in [20] as a 2-state spin variable with an indefinite inner product in the state space. We find that whenever the spin sector is disentangled from the ghost-spin sector (both of which could be entangled within themselves, the reduced density matrix obtained by tracing over all the ghost-spins gives rise to positive entanglement entropy for positive norm states, while negative norm states have an entanglement entropy with a negative real part and a constant imaginary part. However when the spins are entangled with the ghost-spins, there are new entanglement patterns in general. For systems where the number of ghost-spins is even, it is possible to find subsectors of the Hilbert space where positive norm states always lead to positive entanglement entropy after tracing over the ghost-spins. With an odd number of ghost-spins however, we find that there always exist positive norm states with negative real part for entanglement entropy after tracing over the ghost-spins.

  15. Synthesis of carbon-13 labeled ibuprofen

    International Nuclear Information System (INIS)

    Hsi, R.S.P.; Stelzer, L.S.; Stolle, W.T.

    1989-01-01

    This report describes the synthesis of 2-[4-(2-methyl)propyl-phenyl]propionic acid (ibuprofen) labeled with carbon-13 either at the terminal methyl carbons, or at the methine carbon of the isobutyl side chain. The synthetic route involves the removal of the isopropyl group in the isobutyl side-chain of ibuprofen via 2-[4-(2-methyl-1-propenyl)phenyl]propionic acid, followed by restoration of the isopropyl group with a Wittig reaction, using appropriate carbon-13 labeled acetone as the precursor of the isopropyl group. Interesting NMR coupling data attributable to phosphorous and carbon-13 are presented in the experimental section. (author)

  16. Synthesis and preliminary evaluation of {sup 18}F-labeled 4-thia palmitate as a PET tracer of myocardial fatty acid oxidation

    Energy Technology Data Exchange (ETDEWEB)

    DeGrado, Timothy R. E-mail: trd@petsparc.mc.duke.edu; Wang Shuyan; Holden, James E.; Nickles, R. Jerome; Taylor, Michael; Stone, Charles K

    2000-04-01

    Interest remains strong for the development of a noninvasive technique for assessment of regional fatty acid oxidation rate in the myocardium. {sup 18}F-labeled 4-thia palmitate (FTP, 16-[{sup 18}F]fluoro-4-thia-hexadecanoic acid) has been synthesized and preliminarily evaluated as a metabolically trapped probe of myocardial fatty acid oxidation for positron emission tomography (PET). The radiotracer is synthesized by Kryptofix 2.2.2/K{sub 2}CO{sub 3} assisted nucleophilic radiofluorination of an iodo-ester precursor, followed by alkaline hydrolysis and by purification by reverse phase high performance liquid chromatography. Biodistribution studies in rats showed high uptake and long retention of FTP in heart, liver, and kidneys consistent with relatively high fatty acid oxidation rates in these tissues. Inhibition of carnitine palmitoyl-transferase-I caused an 80% reduction in myocardial uptake, suggesting the dependence of trapping on the transport of tracer into the mitochondrion. Experiments with perfused rat hearts showed that the estimates of the fractional metabolic trapping rate (FR) of FTP tracked inhibition of oxidation rate of palmitate with hypoxia, whereas the FR of the 6-thia analog 17-[{sup 18}F]fluoro-6-thia-heptadecanoic acid was insensitive to hypoxia. In vivo defluorination of FTP in the rat was evidenced by bone uptake of radioactivity. A PET imaging study with FTP in normal swine showed excellent myocardial images, prolonged myocardial retention, and no bone uptake of radioactivity up to 3 h, the last finding suggesting a species dependence for defluorination of the omega-labeled fatty acid. The results support further investigation of FTP as a potential PET tracer for assessing regional fatty acid oxidation rate in the human myocardium.

  17. Spin Current Noise of the Spin Seebeck Effect and Spin Pumping

    Science.gov (United States)

    Matsuo, M.; Ohnuma, Y.; Kato, T.; Maekawa, S.

    2018-01-01

    We theoretically investigate the fluctuation of a pure spin current induced by the spin Seebeck effect and spin pumping in a normal-metal-(NM-)ferromagnet(FM) bilayer system. Starting with a simple ferromagnet-insulator-(FI-)NM interface model with both spin-conserving and non-spin-conserving processes, we derive general expressions of the spin current and the spin-current noise at the interface within second-order perturbation of the FI-NM coupling strength, and estimate them for a yttrium-iron-garnet-platinum interface. We show that the spin-current noise can be used to determine the effective spin carried by a magnon modified by the non-spin-conserving process at the interface. In addition, we show that it provides information on the effective spin of a magnon, heating at the interface under spin pumping, and spin Hall angle of the NM.

  18. Arterial spin labelling perfusion MRI of breast cancer using FAIR TrueFISP: Initial results

    International Nuclear Information System (INIS)

    Buchbender, S.; Obenauer, S.; Mohrmann, S.; Martirosian, P.; Buchbender, C.; Miese, F.R.; Wittsack, H.J.; Miekley, M.; Antoch, G.; Lanzman, R.S.

    2013-01-01

    Aim: To assess the feasibility of an unenhanced, flow-sensitive, alternating inversion recovery-balanced steady-state free precession (FAIR TrueFISP) arterial spin labelling (ASL) magnetic resonance imaging (MRI) technique for quantification of breast cancer perfusion. Materials and methods: Eighteen untreated breast tumour patients (mean age 53 ± 17 years, range 30–68 years) and four healthy controls (mean age 51 ± 14 years, range 33–68 years) were enrolled in this study and were imaged using a clinical 1.5 T MRI machine. Perfusion measurements were performed using a coronal single-section ASL FAIR TrueFISP technique in addition to a routine breast MRI examination. T1 relaxation time of normal breast parenchyma was determined in four healthy volunteers using the variable flip angle approach. The definitive diagnosis was obtained at histology after biopsy or surgery and was available for all patients. Results: ASL perfusion was successfully acquired in 13 of 18 tumour patients and in all healthy controls. The mean ASL perfusion of invasive ductal carcinoma tissue was significantly higher (88.2 ± 39.5 ml/100 g/min) compared to ASL perfusion of normal breast parenchyma (24.9 ± 12.7 ml/100 g/min; p < 0.05) and invasive lobular carcinoma (30.5 ± 4.3 ml/100 g/min; p < 0.05). No significant difference was found between the mean ASL perfusion of normal breast parenchyma and invasive lobular carcinoma tissue (p = 0.97). Conclusion: ASL MRI enables quantification of breast cancer perfusion without the use of contrast material. However, its impact on diagnosis and therapy management of breast tumours has to be evaluated in larger patient studies

  19. Transit time corrected arterial spin labeling technique aids to overcome delayed transit time effect

    International Nuclear Information System (INIS)

    Yun, Tae Jin; Sohn, Chul-Ho; Yoo, Roh-Eul; Kang, Kyung Mi; Choi, Seung Hong; Kim, Ji-hoon; Park, Sun-Won; Hwang, Moonjung; Lebel, R.M.

    2018-01-01

    This study aimed to evaluate the usefulness of transit time corrected cerebral blood flow (CBF) maps based on multi-phase arterial spin labeling MR perfusion imaging (ASL-MRP). The Institutional Review Board of our hospital approved this retrospective study. Written informed consent was waived. Conventional and multi-phase ASL-MRPs and dynamic susceptibility contrast MR perfusion imaging (DSC-MRP) were acquired for 108 consecutive patients. Vascular territory-based volumes of interest were applied to CBF and time to peak (TTP) maps obtained from DSC-MRP and CBF maps obtained from conventional and multi-phase ASL-MRPs. The concordances between normalized CBF (nCBF) from DSC-MRP and nCBF from conventional and transition time corrected CBF maps from multi-phase ASL-MRP were evaluated using Bland-Altman analysis. In addition, the dependence of difference between nCBF (ΔnCBF) values obtained from DSC-MRP and conventional ASL-MRP (or multi-phase ASL-MRP) on TTP obtained from DSC-MRP was also analyzed using regression analysis. The values of nCBFs from conventional and multi-phase ASL-MRPs had lower values than nCBF based on DSC-MRP (mean differences, 0.08 and 0.07, respectively). The values of ΔnCBF were dependent on TTP values from conventional ASL-MRP technique (F = 5.5679, P = 0.0384). No dependency of ΔnCBF on TTP values from multi-phase ASL-MRP technique was revealed (F = 0.1433, P > 0.05). The use of transit time corrected CBF maps based on multi-phase ASL-MRP technique can overcome the effect of delayed transit time on perfusion maps based on conventional ASL-MRP. (orig.)

  20. Transit time corrected arterial spin labeling technique aids to overcome delayed transit time effect

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Tae Jin; Sohn, Chul-Ho; Yoo, Roh-Eul; Kang, Kyung Mi; Choi, Seung Hong; Kim, Ji-hoon [Seoul National University Medical Research Center, Institute of Radiation Medicine, Seoul (Korea, Republic of); Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of); Park, Sun-Won [Seoul National University Medical Research Center, Institute of Radiation Medicine, Seoul (Korea, Republic of); Seoul National University Boramae Medical Center, Department of Radiology, Seoul (Korea, Republic of); Hwang, Moonjung [GE Healthcare Korea, Seoul (Korea, Republic of); Lebel, R.M. [GE Healthcare Canada, Calgary (Canada)

    2018-03-15

    This study aimed to evaluate the usefulness of transit time corrected cerebral blood flow (CBF) maps based on multi-phase arterial spin labeling MR perfusion imaging (ASL-MRP). The Institutional Review Board of our hospital approved this retrospective study. Written informed consent was waived. Conventional and multi-phase ASL-MRPs and dynamic susceptibility contrast MR perfusion imaging (DSC-MRP) were acquired for 108 consecutive patients. Vascular territory-based volumes of interest were applied to CBF and time to peak (TTP) maps obtained from DSC-MRP and CBF maps obtained from conventional and multi-phase ASL-MRPs. The concordances between normalized CBF (nCBF) from DSC-MRP and nCBF from conventional and transition time corrected CBF maps from multi-phase ASL-MRP were evaluated using Bland-Altman analysis. In addition, the dependence of difference between nCBF (ΔnCBF) values obtained from DSC-MRP and conventional ASL-MRP (or multi-phase ASL-MRP) on TTP obtained from DSC-MRP was also analyzed using regression analysis. The values of nCBFs from conventional and multi-phase ASL-MRPs had lower values than nCBF based on DSC-MRP (mean differences, 0.08 and 0.07, respectively). The values of ΔnCBF were dependent on TTP values from conventional ASL-MRP technique (F = 5.5679, P = 0.0384). No dependency of ΔnCBF on TTP values from multi-phase ASL-MRP technique was revealed (F = 0.1433, P > 0.05). The use of transit time corrected CBF maps based on multi-phase ASL-MRP technique can overcome the effect of delayed transit time on perfusion maps based on conventional ASL-MRP. (orig.)

  1. Arterial spin labelling shows functional depression of non-lesion tissue in chronic Wernicke's aphasia.

    Science.gov (United States)

    Robson, Holly; Specht, Karsten; Beaumont, Helen; Parkes, Laura M; Sage, Karen; Lambon Ralph, Matthew A; Zahn, Roland

    2017-07-01

    Behavioural impairment post-stroke is a consequence of structural damage and altered functional network dynamics. Hypoperfusion of intact neural tissue is frequently observed in acute stroke, indicating reduced functional capacity of regions outside the lesion. However, cerebral blood flow (CBF) is rarely investigated in chronic stroke. This study investigated CBF in individuals with chronic Wernicke's aphasia (WA) and examined the relationship between lesion, CBF and neuropsychological impairment. Arterial spin labelling CBF imaging and structural MRIs were collected in 12 individuals with chronic WA and 13 age-matched control participants. Joint independent component analysis (jICA) investigated the relationship between structural lesion and hypoperfusion. Partial correlations explored the relationship between lesion, hypoperfusion and language measures. Joint ICA revealed significant differences between the control and WA groups reflecting a large area of structural lesion in the left posterior hemisphere and an associated area of hypoperfusion extending into grey matter surrounding the lesion. Small regions of remote cortical hypoperfusion were observed, ipsilateral and contralateral to the lesion. Significant correlations were observed between the neuropsychological measures (naming, repetition, reading and semantic association) and the jICA component of interest in the WA group. Additional ROI analyses found a relationship between perfusion surrounding the core lesion and the same neuropsychological measures. This study found that core language impairments in chronic WA are associated with a combination of structural lesion and abnormal perfusion in non-lesioned tissue. This indicates that post-stroke impairments are due to a wider disruption of neural function than observable on structural T1w MRI. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  2. Study on Chinese herbal medicine active ingredients labelled with tritium

    International Nuclear Information System (INIS)

    Dong Mo; Bao Guangliang

    2008-01-01

    Chinese medicinal herb active ingredients was labeled with triteium by using exchange of new synthesized tritiated water or exchange of low-pressure gas-liquid. The active ingredients was Genipin, acetylalkannin and chlorogenic acid .The radiochemical purity of the three labeled compounds were more than 95% after TLC and HPLC purification. The specific activities of tritium labeled-genipin, acetylalkannin and chlorogenic acid were 5.97, 3.24 and 470 GBq/g, respectively. The results indicated that the unstable Chinese medicinal herb active ingredients could be labeled with tritium by the methods of exchange of new synthesized tritiated water and exchange of low-pressure gas-liquid. (authors)

  3. The spin-statistics connection in quantum gravity

    International Nuclear Information System (INIS)

    Balachandran, A.P.; Batista, E.; Costa e Silva, I.P.; Teotonio-Sobrinho, P.

    2000-01-01

    It is well known that in spite of sharing some properties with conventional particles, topological geons in general violate the spin-statistics theorem. On the other hand, it is generally believed that in quantum gravity theories allowing for topology change, using pair creation and annihilation of geons, one should be able to recover this theorem. In this paper, we take an alternative route, and use an algebraic formalism developed in previous work. We give a description of topological geons where an algebra of 'observables' is identified and quantized. Different irreducible representations of this algebra correspond to different kinds of geons, and are labeled by a non-abelian 'charge' and 'magnetic flux'. We then find that the usual spin-statistics theorem is indeed violated, but a new spin-statistics relation arises, when we assume that the fluxes are superselected. This assumption can be proved if all observables are local, as is generally the case in physical theories. Finally, we also discuss how our approach fits into conventional formulations of quantum gravity

  4. Chemoenzymatic synthesis of carbon-14 labelled antioxidants

    International Nuclear Information System (INIS)

    Deigner, H.P.; Freyberg, C.; Heck, R.

    1993-01-01

    The syntheses of [ 14 C] labelled antioxidants are described. We developed an efficient synthetic methodology to prepare a series of labelled amides with antioxidant activity, starting from [ 14 C] KCN and alkyl or aryl halides. By a combination of nucleophilic displacement of halides by [ 14 C] cyanide, mediated by ultrasound and subsequent mild and selective enzymatic hydrolysis of the resulting nitriles, labelled carboxylic acids were obtained. Labelled amines were prepared by reduction of the respective nitriles. Availability of [ 14 C] KCN, efficient introduction of the label by ultrasound mediated reaction and selective and mild hydrolysis by commercially available nitrilase (Rhodococcus sp.), makes possible a wide range of applications of this methodology in the synthesis of functionalized labelled compounds. (Author)

  5. Metabolism of [14C]bicarbonate by Streptococcus lactis: identification and distribution of labelled compounds

    International Nuclear Information System (INIS)

    Hillier, A.J.; Jago, G.R.

    1978-01-01

    Streptococcus lactis C10, grown in tryptone-yeast extract-lactose broth containing [ 14 C] bicarbonate, incorporated radioactivity into the protein and nucleic acid fractions of the cell as well as into compounds which were excreted by the organism into the growth medium. Aspartic acid was the first compound to be labelled and was the only amino acid labelled in the cell protein. All 4 bases were labelled in the cell RNA. Aspartic, succunuc and lactic acids were the radioactive compounds excreted into the growth medium. (U.K.)

  6. Radiophotosynthesis of some sup 14 C-labelled amino acids using the unicellular green alga Scenedesmus acutus

    Energy Technology Data Exchange (ETDEWEB)

    Barakat, M.F.; Farag, A.N.; Ragab, M.T. (Atomic Energy Establishment, Cairo (Egypt). Nuclear Chemistry Dept.); El-Fouly, M.M.; El-Baz, F.K. (National Research Centre, Cairo (Egypt). Botany Lab.)

    1990-01-01

    Radiophotosynthesis has been carried out using the unicellular green algea Scenedesmus acutus grown, as a substrate for preparing some carbon-14 labelled amino acids. Gaseous {sup 14}CO{sub 2}, in an air tight photosynthesis chamber or NaH{sup 14}CO{sub 3} solution, in an ordinary phtosynthesis chamber, were used as radioactive carbon sources. The yields, radiochemical yields and specific activities of the formed radioactive products are reported in both cases. The results obtained clearly showed the advantages of usingthe NaH{sup 14}CO{sub 3} method. In that case the process was by far less tedious. Moreover, the chemical and radiochemical yields of the formed amino acids were relatively much more higher than the values obtained on using {sup 14}CO{sub 2} in the tight photosynthesis chamber. (orig.).

  7. Short-lived positron emitter labeled radiotracers - present status

    International Nuclear Information System (INIS)

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

    1982-01-01

    The preparation of labelled compounds is important for the application of positron emission transaxial tomography (PETT) in biomedical sciences. This paper describes problems and progress in the synthesis of short-lived positron emitter ( 11 C, 18 F, 13 N) labelled tracers for PETT. Synthesis of labelled sugars, amino acids, and neurotransmitter receptors (pimozide and spiroperidol tagged with 11 C) is discussed in particular

  8. Synthesis of Ethane-1-Hydroxy-1,1-diphosphonic acid (EHDP) and preparation of labeled kits by 99mTc for bone studies

    International Nuclear Information System (INIS)

    Yassin, T.; Assaad, T.; Ghanem, E.; Ajaia, R.; Karajoli, N.

    2013-08-01

    Ethane-1-Hydroxy-1,1-diphosphonic acid monohydrate (EHDP) is very important precursor in radiopharmaceutical applications for bone diagnosis after labeling with 99mTc, was synthesized in high yield and purity. The compound was characterized by spectroscopic method. EHDP kit for bone imaging after labeling with technetium 99m was prepared according to an optimum conditions, Each vial contains 15 mg of EHDP and 25 mg of stannous chloride SnCl2. The prepared kit showed high quality satisfying the requirements of international pharmacopeias from of physical, chemical and radiochemical properties. The labeling yield exceeded 95% with an average value 99.6%. Biodistribution study of 99mTc-EHDP showed better clearance after three hours of injection in comparison with 99mTc-MDP kit (author).

  9. Sensitive determination of pipecolic acid in serum by high-performance liquid chromatography using 4-(5,6-dimethoxy-2-phthalimidinyl)-2-methoxyphenylsulfonyl chloride as a fluorescent labelling reagent

    International Nuclear Information System (INIS)

    Inoue, Hirofumi; Sakata, Yasuhiko; Fukunaga, Keiko; Nishio, Hiroaki; Tsuruta, Yasuto

    2004-01-01

    A simple and highly sensitive high-performance liquid chromatography (HPLC) for the determination of pipecolic acid (PA) in serum was developed. Pipecolic acid and nipecotic acid (internal standard (IS)) were derivatised with 4-(5,6-dimethoxy-2-phthalimidinyl)-2-methoxyphenylsulfonyl chloride (DMS-Cl) to produce fluorescent sulfonamides. The labelling reaction was carried out at 70 degree sign C for 15 min at pH 9.0. The fluorescent derivatives were separated on a reversed-phase column (45 degree sign C) with a stepwise elution using methanol/acetonitrile/10 mmol l -1 acetic acid (42:5:53) and methanol at a flow rate of 1.0 ml/min and detected at excitation and emission wavelengths of 316 and 403 nm, respectively. The labelling yield was 100.8%. The detection limit of pipecolic acid was 4 fmol at signal-to-noise ratio of 3. The within-day and day-to-day relative standard deviations were 3.3-8.1 and 1.4-6.4%, respectively. The concentration of pipecolic acid in normal human serum was 1.09±0.37 μmol l -1

  10. Geometrical spin symmetry and spin

    International Nuclear Information System (INIS)

    Pestov, I. B.

    2011-01-01

    Unification of General Theory of Relativity and Quantum Mechanics leads to General Quantum Mechanics which includes into itself spindynamics as a theory of spin phenomena. The key concepts of spindynamics are geometrical spin symmetry and the spin field (space of defining representation of spin symmetry). The essence of spin is the bipolar structure of geometrical spin symmetry induced by the gravitational potential. The bipolar structure provides a natural derivation of the equations of spindynamics. Spindynamics involves all phenomena connected with spin and provides new understanding of the strong interaction.

  11. The Degradation of 14C-Glutamic Acid by L-Glutamic Acid Decarboxylase.

    Science.gov (United States)

    Dougherty, Charles M; Dayan, Jean

    1982-01-01

    Describes procedures and semi-micro reaction apparatus (carbon dioxide trap) to demonstrate how a particular enzyme (L-Glutamic acid decarboxylase) may be used to determine the site or sites of labeling in its substrate (carbon-14 labeled glutamic acid). Includes calculations, solutions, and reagents used. (Author/SK)

  12. Indium-111 tropolone, a new high-affinity platelet label: preparation and evaluation of labeling parameters

    International Nuclear Information System (INIS)

    Dewanjee, M.K.; Rao, S.A.; Didisheim, P.

    1981-01-01

    Platelets were isolated with a new neutral, lipid-soluble metal complex of indium-111 and tropolone. Unlike oxine, which must be dissolved in ethyl alcohol, tropolone is soluble saline. Platelet labeling with In-111 tropolone can be performed in both acid-citrate-dextrose (ACD)-plasma and ACD-saline media within two hours' time. Labeling efficiency has been 80-90% in ACD-saline and 60-70% in the ACD-plasma medium. Optimum concentrations for the labeling of platelets with In-111 tropolone were 5 micrograms/ml in ACD-saline and 10 micrograms/ml in ACD-plasma, using a 15-min incubation at room temperature. A kit formulation for convenient routine preparation of In-111-labeled platelets has been developed. Seven parameters of platelet labeling were studied: concentration of tropolone, citrate, plasma proteins, and calcium ions; also platelet density, temperature, and pH of incubation medium. Their effects on the mechanism of platelet labeling with lipid-soluble tracers are discussed

  13. The fate of (13)C-labelled and non-labelled inulin predisposed to large bowel fermentation in rats.

    Science.gov (United States)

    Butts, Christine A; Paturi, Gunaranjan; Tavendale, Michael H; Hedderley, Duncan; Stoklosinski, Halina M; Herath, Thanuja D; Rosendale, Douglas; Roy, Nicole C; Monro, John A; Ansell, Juliet

    2016-04-01

    The fate of stable-isotope (13)C labelled and non-labelled inulin catabolism by the gut microbiota was assessed in a healthy rat model. Sprague-Dawley male rats were randomly assigned to diets containing either cellulose or inulin, and were fed these diets for 3 days. On day (d) 4, rats allocated to the inulin diet received (13)C-labelled inulin. The rats were then fed the respective non-labelled diets (cellulose or inulin) until sampling (d4, d5, d6, d7, d10 and d11). Post feeding of (13)C-labelled substrate, breath analysis showed that (13)C-inulin cleared from the host within a period of 36 hours. Faecal (13)C demonstrated the clearance of inulin from gut with a (13)C excess reaching maximum at 24 hours (d5) and then declining gradually. There were greater variations in caecal organic acid concentrations from d4 to d6, with higher concentrations of acetic, butyric and propionic acids observed in the rats fed inulin compared to those fed cellulose. Inulin influenced caecal microbial glycosidase activity, increased colon crypt depth, and decreased the faecal output and polysaccharide content compared to the cellulose diet. In summary, the presence of inulin in the diet positively influenced large bowel microbial fermentation.

  14. Stable isotope labelling with amino acids in cell culture for human embryonic stem cell proteomic analysis

    DEFF Research Database (Denmark)

    Harkness, Linda; Prokhorova, Tatyana A; Kassem, Moustapha

    2012-01-01

    The identification and quantitative measurements of proteins in human embryonic stem cells (hESC) is a fast growing interdisciplinary area with an enormous impact on understanding the biology of hESC and the mechanism controlling self-renewal and differentiation. Using a quantitative mass...... spectroscopic method of stable isotope labelling with amino acids during cell culture (SILAC), we are able to analyse differential expression of proteins from different cellular compartments and to identify intracellular signalling pathways involved in self-renewal and differentiation. In this chapter, we...

  15. Validation of 99mTc-labeled '4+1' fatty acids for myocardial metabolism and flow imaging

    International Nuclear Information System (INIS)

    Mirtschink, Peter; Stehr, Sebastian N.; Walther, Martin; Pietzsch, Jens; Bergmann, Ralf; Pietzsch, Hans-Juergen; Weichsel, Johannes; Pexa, Annette; Dieterich, Peter; Wunderlich, Gerd; Binas, Bert; Kropp, Joachim; Deussen, Andreas

    2009-01-01

    Introduction: Our group has synthesized technetium-labeled fatty acids (FA) that are extracted into the myocardium and sequestered due to heart-type fatty acid binding protein (H-FABP) binding. In this article, we further address the detailed subcellular distribution and potential myocardial metabolism of [ 99m Tc]'4+1' FA. Methods: Experiments were conducted using isolated hearts of Wistar rats, as well as of wild-type and H-FABP -/- mice. Myocardium samples underwent subcellular fractionation [subsarcolemmal mitochondria (SM), intermyofibrillar mitochondria (IM), cytosol with microsomes, and nuclei and crude membranes] and analysis by thin-layer chromatography and high-performance liquid chromatography. Results: The largest fraction of tissue radioactivity was associated with cytosol [79.69±8.88% of infused dose]. About 9.07±0.95% and 3.43±1.38% of the infused dose were associated with SM and IM fractions, respectively. In the rat heart, etomoxir, an inhibitor of carnitin-palmitoyl transferase I, did not significantly decrease radioactivity associated with mitochondrial fractions, whereas myocardial extraction of [ 123 I]-labeled 15-(p-iodophenyl)-pentadecanoic acid (13.26% vs. 49.49% in controls) and the radioactivity associated with the SM and IM fractions were blunted. The percentage of the infused dose in the mitochondrial and crude fractions increased with the number of NH-amide groups of the FA derivative. Absence of H-FABP significantly decreased radioactivity count in the cytosolic fraction (P 99m Tc]'4+1' FA could be detected in any isolated heart. Conclusions: Myocardial [ 99m Tc]'4+1' FA extraction reflects binding to H-FABP and membrane structures (including the mitochondrial membrane). However, the compounds do not undergo mitochondrial metabolism because they do not reach the mitochondrial matrix.

  16. Purely geometric path integral for spin-foams

    International Nuclear Information System (INIS)

    Shirazi, Atousa Chaharsough; Engle, Jonathan

    2014-01-01

    Spin-foams are a proposal for defining the dynamics of loop quantum gravity via path integral. In order for a path integral to be at least formally equivalent to the corresponding canonical quantization, at each point in the space of histories it is important that the integrand have not only the correct phase—a topic of recent focus in spin-foams—but also the correct modulus, usually referred to as the measure factor. The correct measure factor descends from the Liouville measure on the reduced phase space, and its calculation is a task of canonical analysis. The covariant formulation of gravity from which spin-foams are derived is the Plebanski–Holst formulation, in which the basic variables are a Lorentz connection and a Lorentz-algebra valued 2-form, called the Plebanski 2-form. However, in the final spin-foam sum, one usually sums over only spins and intertwiners, which label eigenstates of the Plebanski 2-form alone. The spin-foam sum is therefore a discretized version of a Plebanski–Holst path integral in which only the Plebanski 2-form appears, and in which the connection degrees of freedom have been integrated out. We call this a purely geometric Plebanski–Holst path integral. In prior work in which one of the authors was involved, the measure factor for the Plebanski–Holst path integral with both connection and 2-form variables was calculated. Before one discretizes this measure and incorporates it into a spin-foam sum, however, one must integrate out the connection in order to obtain the purely geometric version of the path integral. To calculate this purely geometric path integral is the principal task of the present paper, and it is done in two independent ways. Background independence of the resulting path integral is discussed in the final section, and gauge-fixing is discussed in appendix B. (paper)

  17. Simple and Robust N-Glycan Analysis Based on Improved 2-Aminobenzoic Acid Labeling for Recombinant Therapeutic Glycoproteins.

    Science.gov (United States)

    Jeong, Yeong Ran; Kim, Sun Young; Park, Young Sam; Lee, Gyun Min

    2018-03-21

    N-glycans of therapeutic glycoproteins are critical quality attributes that should be monitored throughout all stages of biopharmaceutical development. To reduce both the time for sample preparation and the variations in analytical results, we have developed an N-glycan analysis method that includes improved 2-aminobenzoic acid (2-AA) labeling to easily remove deglycosylated proteins. Using this analytical method, 15 major 2-AA-labeled N-glycans of Enbrel ® were separated into single peaks in hydrophilic interaction chromatography mode and therefore could be quantitated. 2-AA-labeled N-glycans were also highly compatible with in-line quadrupole time-of-flight mass spectrometry (MS) for structural identification. The structures of 15 major and 18 minor N-glycans were identified from their mass values determined by quadrupole time-of-flight MS. Furthermore, the structures of 14 major N-glycans were confirmed by interpreting the MS/MS data of each N-glycan. This analytical method was also successfully applied to neutral N-glycans of Humira ® and highly sialylated N-glycans of NESP ® . Furthermore, the analysis data of Enbrel ® that were accumulated for 2.5 years demonstrated the high-level consistency of this analytical method. Taken together, the results show that a wide repertoire of N-glycans of therapeutic glycoproteins can be analyzed with high efficiency and consistency using the improved 2-AA labeling-based N-glycan analysis method. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  18. Global Structure of a Three-Way Junction in a Phi29 Packaging RNA Dimer Determined Using Site-Directed Spin Labeling

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaojun; Tung, Chang-Shung; Sowa, Glenna; Hatmal, Ma' mon M.; Haworth, Ian S.; Qin, Peter Z.

    2012-02-08

    The condensation of bacteriophage phi29 genomic DNA into its preformed procapsid requires the DNA packaging motor, which is the strongest known biological motor. The packaging motor is an intricate ring-shaped protein/RNA complex, and its function requires an RNA component called packaging RNA (pRNA). Current structural information on pRNA is limited, which hinders studies of motor function. Here, we used site-directed spin labeling to map the conformation of a pRNA three-way junction that bridges binding sites for the motor ATPase and the procapsid. The studies were carried out on a pRNA dimer, which is the simplest ring-shaped pRNA complex and serves as a functional intermediate during motor assembly. Using a nucleotide-independent labeling scheme, stable nitroxide radicals were attached to eight specific pRNA sites without perturbing RNA folding and dimer formation, and a total of 17 internitroxide distances spanning the three-way junction were measured using Double Electron-Electron Resonance spectroscopy. The measured distances, together with steric chemical constraints, were used to select 3662 viable three-way junction models from a pool of 65 billion. The results reveal a similar conformation among the viable models, with two of the helices (HT and HL) adopting an acute bend. This is in contrast to a recently reported pRNA tetramer crystal structure, in which HT and HL stack onto each other linearly. The studies establish a new method for mapping global structures of complex RNA molecules, and provide information on pRNA conformation that aids investigations of phi29 packaging motor and developments of pRNA-based nanomedicine and nanomaterial.

  19. Ultraviolet B irradiation induces changes in the distribution and release of arachidonic acid, dihomo-gamma-linolenic acid, and eicosapentaenoic acid in human keratinocytes in culture

    International Nuclear Information System (INIS)

    Punnonen, K.; Puustinen, T.; Jansen, C.T.

    1987-01-01

    There is increasing evidence that derivatives of 20-carbon polyunsaturated fatty acids, the eicosanoids, play an important role in the inflammatory responses of the human skin. To better understand the metabolic fate of fatty acids in the skin, the effect of ultraviolet B (UVB) irradiation (280-320 nm) on the distribution and release of 14 C-labeled arachidonic acid, dihomo-gamma-linolenic acid, and eicosapentaenoic acid in human keratinocytes in culture was investigated. Ultraviolet B irradiation induced the release of all three 14 C-labeled fatty acids from the phospholipids, especially from phosphatidylethanolamine, and this was accompanied by increased labeling of the nonphosphorus lipids. This finding suggests that UVB induces a significant liberation of eicosanoid precursor fatty acids from cellular phospholipids, but the liberated fatty acids are largely reincorporated into the nonphosphorus lipids. In conclusion, the present study suggests that not only arachidonic acid but also dihomo-gamma-linolenic acid, and eicosapentaenoic acid might be involved in the UVB irradiation-induced inflammatory reactions of human skin

  20. Impact of nucleic acid self-alignment in a strong magnetic field on the interpretation of indirect spin-spin interactions

    Czech Academy of Sciences Publication Activity Database

    Vavrinská, A.; Zelinka, J.; Šebera, Jakub; Sychrovský, Vladimír; Fiala, R.; Boelens, R.; Sklenář, V.; Trantírek, L.

    2016-01-01

    Roč. 64, č. 1 (2016), s. 53-62 ISSN 0925-2738 R&D Projects: GA ČR GA13-27676S Grant - others:AV ČR(CZ) M200551205 Institutional support: RVO:61388963 Keywords : NMR * DFT calculations * spin-spin interactions * magnetic field Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.410, year: 2016 http://link.springer.com/article/10.1007/s10858-015-0005-x

  1. Site-selective {sup 13}C labeling of proteins using erythrose

    Energy Technology Data Exchange (ETDEWEB)

    Weininger, Ulrich, E-mail: ulrich.weininger@physik.uni-halle.de [Lund University, Department of Biophysical Chemistry, Center for Molecular Protein Science (Sweden)

    2017-03-15

    NMR-spectroscopy enables unique experimental studies on protein dynamics at atomic resolution. In order to obtain a full atom view on protein dynamics, and to study specific local processes like ring-flips, proton-transfer, or tautomerization, one has to perform studies on amino-acid side chains. A key requirement for these studies is site-selective labeling with {sup 13}C and/or {sup 1}H, which is achieved in the most general way by using site-selectively {sup 13}C-enriched glucose (1- and 2-{sup 13}C) as the carbon source in bacterial expression systems. Using this strategy, multiple sites in side chains, including aromatics, become site-selectively labeled and suitable for relaxation studies. Here we systematically investigate the use of site-selectively {sup 13}C-enriched erythrose (1-, 2-, 3- and 4-{sup 13}C) as a suitable precursor for {sup 13}C labeled aromatic side chains. We quantify {sup 13}C incorporation in nearly all sites in all 20 amino acids and compare the results to glucose based labeling. In general the erythrose approach results in more selective labeling. While there is only a minor gain for phenylalanine and tyrosine side-chains, the {sup 13}C incorporation level for tryptophan is at least doubled. Additionally, the Phe ζ and Trp η2 positions become labeled. In the aliphatic side chains, labeling using erythrose yields isolated {sup 13}C labels for certain positions, like Ile β and His β, making these sites suitable for dynamics studies. Using erythrose instead of glucose as a source for site-selective {sup 13}C labeling enables unique or superior labeling for certain positions and is thereby expanding the toolbox for customized isotope labeling of amino-acid side-chains.

  2. Preparation and in vivo biological investigations on a novel radioligand for bone scanning: technetium-99m-labeled zoledronic acid derivative

    International Nuclear Information System (INIS)

    Lin Jianguo; Qiu Ling; Cheng Wen; Luo Shineng; Ye Wanzhong

    2011-01-01

    Introduction: To enable imaging at an earlier time after injection, a radiopharmaceutical with higher affinity for bone, larger ratio of bone-to-soft tissue uptake and more rapid clearance from blood is required. The nature of diphosphonic acid is a key factor to determine the advantages of the radiopharmaceuticals. The purpose of this study is to optimize the linker chain between the imidazolyl and geminal diphosphonate group in the zoledronic acid (ZL) to develop novel single photon emission computed tomography (SPECT) bone imaging agent. Methods: A novel ZL derivative, 1-hydroxy-3-(1H-imidazol-1-yl)propane-1,1-diyldiphosphonic acid (IPrDP), was successfully prepared and labeled with 99m Tc in a high labeling yield. Biodistribution of 99m Tc-IPrDP and 99m Tc-ZL in normal mice were studied and compared. SPECT bone scanning was performed on the rabbit and a series of dynamic and static images were recorded by Philips SKY Light emission computed tomography. Results: In the biodistribution studies, 99m Tc-IPrDP exhibits significant advantages on the bone resorption and the clearance from soft tissues compared with 99m Tc-ZL. Kinetics of blood clearance in mice showed that T 1/2α and T 1/2β of 99m Tc-IPrDP were 1.47 min and 46.47 min, while those of 99m Tc-ZL were 2.28 and 52.63 min respectively. Excellent images of the rabbit skeleton can be quickly obtained for 99m Tc-IPrDP, which was faster than 99m Tc-ZL and the clinically widely used bone imaging agent 99m Tc-MDP (technetium-99m labeled with methylenediphosphonate). Conclusions: 99m Tc-IPrDP possesses excellent characteristics for the potential application as a novel bone scanning agent.

  3. Fatty acid oxidation and ketogenesis in astrocytes

    International Nuclear Information System (INIS)

    Auestad, N.

    1988-01-01

    Astrocytes were derived from cortex of two-day-old rat brain and grown in primary culture to confluence. The metabolism of the fatty acids, octanoate and palmitate, to CO 2 in oxidative respiration and to the formation of ketone bodies was examined by radiolabeled tracer methodology. The net production of acetoacetate was also determined by measurement of its mass. The enzymes in the ketogenic pathway were examined by measuring enzymic activity and/or by immunoblot analyses. Labeled CO 2 and labeled ketone bodies were produced from the oxidation of fatty acids labeled at carboxy- and ω-terminal carbons, indicating that fatty acids were oxidized by β-oxidation. The results from the radiolabeled tracer studies also indicated that a substantial proportion of the ω-terminal 4-carbon unit of the fatty acids bypassed the β-ketothiolase step of the β-oxidation pathway. The [ 14 C]acetoacetate formed from the [1- 14 C]labeled fatty acids, obligated to pass through the acetyl-CoA pool, contained 50% of the label at carbon 3 and 50% at carbon 1. In contrast, the [ 14 C]acetoacetate formed from the (ω-1)labeled fatty acids contained 90% of the label at carbon 3 and 10% at carbon 1

  4. Spin Torques in Systems with Spin Filtering and Spin Orbit Interaction

    KAUST Repository

    Ortiz Pauyac, Christian

    2016-06-19

    In the present thesis we introduce the reader to the field of spintronics and explore new phenomena, such as spin transfer torques, spin filtering, and three types of spin-orbit torques, Rashba, spin Hall, and spin swapping, which have emerged very recently and are promising candidates for a new generation of memory devices in computer technology. A general overview of these phenomena is presented in Chap. 1. In Chap. 2 we study spin transfer torques in tunnel junctions in the presence of spin filtering. In Chap. 3 we discuss the Rashba torque in ferromagnetic films, and in Chap. 4 we study spin Hall effect and spin swapping in ferromagnetic films, exploring the nature of spin-orbit torques based on these mechanisms. Conclusions and perspectives are summarized in Chap. 5.

  5. pH-responsive diblock copolymers with two different fluorescent labels for simultaneous monitoring of micellar self-assembly and degree of protonation

    DEFF Research Database (Denmark)

    Madsen, Jeppe; Madden, George; Themistou, Efrosyni

    2018-01-01

    methacrylate [PyMA] is statistically copolymerized with glycerolmonomethacrylate (GMA) to introduce a suitable fluorescent label. The chain-ends of the PDPA block are labelled with cresylviolet perchlorate [CV] by exploiting the spin trap properties of this dye molecule. Below pH 6, fluorescence from both...

  6. Perfusion imaging of brain gliomas using arterial spin labeling: correlation with histopathological vascular density in MRI-guided biopsies

    Energy Technology Data Exchange (ETDEWEB)

    Di, Ningning; Pang, Haopeng; Ren, Yan; Yao, Zhenwei; Feng, Xiaoyuan [Huashan Hospital Fudan University, Department of Radiology, Shanghai (China); Dang, Xuefei [Shang Hai Gamma Knife Hospital, Shanghai (China); Cheng, Wenna [Binzhou Medical University Affiliated Hospital, Department of Pharmacy, Binzhou (China); Wu, Jingsong; Yao, Chengjun [Huashan Hospital Fudan University, Department of Neurosurgery, Shanghai (China)

    2017-01-15

    This study was designed to determine if cerebral blood flow (CBF) derived from arterial spin labeling (ASL) perfusion imaging could be used to quantitatively evaluate the microvascular density (MVD) of brain gliomas on a ''point-to-point'' basis by matching CBF areas and surgical biopsy sites as accurate as possible. The study enrolled 47 patients with treatment-naive brain gliomas who underwent preoperative ASL, 3D T1-weighted imaging with gadolinium contrast enhancement (3D T1C+), and T2 fluid acquisition of inversion recovery (T2FLAIR) sequences before stereotactic surgery. We histologically quantified MVD from CD34-stained sections of stereotactic biopsies and co-registered biopsy locations with localized CBF measurements. The correlation between CBF and MVD was determined using Spearman's correlation coefficient. P ≤.05 was considered statistically significant. Of the 47 patients enrolled in the study, 6 were excluded from the analysis because of brain shift or poor co-registration and localization of the biopsy site during surgery. Finally, 84 biopsies from 41 subjects were included in the analysis. CBF showed a statistically significant positive correlation with MVD (ρ = 0.567; P =.029). ASL can be a useful noninvasive perfusion MR method for quantitative evaluation of the MVD of brain gliomas. (orig.)

  7. Perfusion imaging of parotid gland tumours: usefulness of arterial spin labeling for differentiating Warthin's tumours

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Hiroki; Watanabe, Haruo [Gifu University School of Medicine, Department of Radiology, Gifu (Japan); Kanematsu, Masayuki [Gifu University School of Medicine, Department of Radiology, Gifu (Japan); Gifu University Hospital, High-level Imaging Diagnosis Center, Gifu (Japan); Kajita, Kimihiro [Gifu University Hospital, High-level Imaging Diagnosis Center, Gifu (Japan); Mizuta, Keisuke; Aoki, Mitsuhiro [Gifu University School of Medicine, Department of Otolaryngology, Gifu (Japan); Okuaki, Tomoyuki [Philips Healthcare, Tokyo (Japan)

    2015-11-15

    To assess prospectively the efficacy of arterial spin labelling (ASL) against conventional and diffusion-weighted (DW) MR imaging for differentiating parotid gland tumours. We included 10 pleomorphic adenomas, 12 Warthin's tumours, and nine malignant tumours of the parotid glands. Only tumours larger than 10 mm were included in this study. All parotid gland tumours underwent T1-weighted, T2-weighted, DW, and ASL imaging. Tumour-to-parotid gland signal intensity ratios (SIRs) and apparent diffusion coefficients (ADCs) of solid components were correlated with these pathologies. SIRs on T2-weighted images and ADCs were higher in pleomorphic adenomas than in Warthin's tumours (p <.01) and malignant tumours (p <.01). SIRs on ASL were higher in Warthin's tumours than in pleomorphic adenomas (p <.01) and malignant tumours (p <.05). Az value of SIRs on ASL for differentiating Warthin's tumours from the other pathologies was 0.982. The sensitivity, specificity, and accuracy of SIRs on ASL for the diagnosis of Warthin's tumours at an optimal SIR threshold of over 8.70 were 91.7 %, 94.7 %, and 93.5 %, respectively. ASL with SIR measurements could non-invasively evaluate tumour blood flow of parotid gland tumours and differentiate Warthin's tumours from pleomorphic adenomas and malignant tumours. (orig.)

  8. Arterial spin labelling MRI for detecting pseudocapsule defects and predicting renal capsule invasion in renal cell carcinoma.

    Science.gov (United States)

    Zhang, H; Wu, Y; Xue, W; Zuo, P; Oesingmann, N; Gan, Q; Huang, Z; Wu, M; Hu, F; Kuang, M; Song, B

    2017-11-01

    To evaluate prospectively the performance of combining morphological and arterial spin labelling (ASL) magnetic resonance imaging (MRI) for detecting pseudocapsule defects in renal cell carcinoma (RCC), and to predict renal capsule invasion confirmed histopathologically. Twenty consecutive patients with suspicious renal tumours underwent MRI. Renal ASL imaging was performed and renal blood flow was measured quantitatively. The diagnostic performance of T2-weighted images alone, and a combination of T2-weighted and ASL images for predicting renal capsule invasion were assessed. Twenty renal lesions were evaluated in 20 patients. All lesions were clear cell RCCs (ccRCCs) confirmed at post-surgical histopathology. Fifteen ccRCCs showed pseudocapsule defects on T2-weighted images, of which 12 cases showed existing blood flow in defect areas on perfusion images. To predict renal capsule invasion, the sensitivity, specificity, positive predictive value, and negative predictive value were 100%, 71.4%, 86.7%, 100%, respectively, for T2-weighted images alone, and 92.3%, 100%, 100%, 87.5%, respectively, for the combination of T2-weighted and ASL images. ASL images can reflect the perfusion of pseudocapsule defects and as such, the combination of T2-weighted and ASL images produces promising diagnostic accuracy for predicting renal capsule invasion. Copyright © 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  9. Labelling of biological structures with technetium 99 m

    International Nuclear Information System (INIS)

    Bernardo Filho, M.

    1988-01-01

    The labelling of red blood cells (RBC) with technetium 99m ( 99m Tc) depends on several factors, as the stannous ion (Sn ++ ) concentration, the time and temperature of incubation, the anticoagulant utilized, the presence of plasma proteins (PP) and others. Although the blinding of 99m Tc with hemoglobin and PP are similar, they appear to have specific characteristics as demonstrated by precipitation with alcohol, acetone, trichloroacetic acid, hydrochloric acid and mercury chloride. The bacterial cultures labeled with Technetium- 99m , at optimal Sn ++ ion concentration, presents a large stability and their viability is not altered by this treatment. The electrophoretic mobility, the hydrophobicity, the cationized ferritin distribution and the adherence to human buccal epithelial cells are not modified either. The possibility of labelling with 99m Tc of planaria and cercariae of Schistossoma mansoni evaluative cycle increases the utilization of this radionuclide to an experimental level. The results described with the labelling of these biological structures with 99m Tc demonstrated that stable labeled and viable operations are obtained. (author)

  10. In vitro studies of leukocyte labeling with /sup 99m/Tc

    International Nuclear Information System (INIS)

    Uchida, T.; Vincent, P.C.

    1976-01-01

    A method for labeling leukocytes in vitro with /sup 99m/Tc is described. Separated leukocytes are incubated with /sup 99m/Tc, followed by reduction with stannous chloride and washing with acid citrate dextrose solution. Maximum labeling occurs after at least 5 min incubation with pertechnetate, followed by at least 10 min incubation with stannous chloride. Labeling is similar at room temperature and at 37 0 C. The labeled leukocytes are viable, and reutilization of label does not occur in vitro. In acid conditions (pH 5.2), the elution of /sup 99m/Tc from leukocytes is comparable with that of 32 P-diisopropylfluorophosphate, but /sup 99m/Tc elution is greater at pH 7.2 to 7.4. Neutrophils label more heavily with /sup 99m/Tc than do monocytes, lymphocytes, erythrocytes, or platelets

  11. Spectral editing at ultra-fast magic-angle-spinning in solid-state NMR: facilitating protein sequential signal assignment by HIGHLIGHT approach

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Songlin; Matsuda, Isamu; Long, Fei; Ishii, Yoshitaka, E-mail: yishii@uic.edu [University of Illinois at Chicago, Department of Chemistry (United States)

    2016-02-15

    This study demonstrates a novel spectral editing technique for protein solid-state NMR (SSNMR) to simplify the spectrum drastically and to reduce the ambiguity for protein main-chain signal assignments in fast magic-angle-spinning (MAS) conditions at a wide frequency range of 40–80 kHz. The approach termed HIGHLIGHT (Wang et al., in Chem Comm 51:15055–15058, 2015) combines the reverse {sup 13}C, {sup 15}N-isotope labeling strategy and selective signal quenching using the frequency-selective REDOR pulse sequence under fast MAS. The scheme allows one to selectively observe the signals of “highlighted” labeled amino-acid residues that precede or follow unlabeled residues through selectively quenching {sup 13}CO or {sup 15}N signals for a pair of consecutively labeled residues by recoupling {sup 13}CO–{sup 15}N dipolar couplings. Our numerical simulation results showed that the scheme yielded only ∼15 % loss of signals for the highlighted residues while quenching as much as ∼90 % of signals for non-highlighted residues. For lysine-reverse-labeled micro-crystalline GB1 protein, the 2D {sup 15}N/{sup 13}C{sub α} correlation and 2D {sup 13}C{sub α}/{sup 13}CO correlation SSNMR spectra by the HIGHLIGHT approach yielded signals only for six residues following and preceding the unlabeled lysine residues, respectively. The experimental dephasing curves agreed reasonably well with the corresponding simulation results for highlighted and quenched residues at spinning speeds of 40 and 60 kHz. The compatibility of the HIGHLIGHT approach with fast MAS allows for sensitivity enhancement by paramagnetic assisted data collection (PACC) and {sup 1}H detection. We also discuss how the HIGHLIGHT approach facilitates signal assignments using {sup 13}C-detected 3D SSNMR by demonstrating full sequential assignments of lysine-reverse-labeled micro-crystalline GB1 protein (∼300 nmol), for which data collection required only 11 h. The HIGHLIGHT approach offers valuable

  12. Fluorine-18 labelled compounds

    International Nuclear Information System (INIS)

    Kleijn, J.P. de

    1978-01-01

    The work presented in this thesis deals with the problems involved in the adaption of reactor-produced fluorine-18 to the synthesis of 18 F-labelled organic fluorine compounds. Several 18 F-labelling reagents were prepared and successfully applied. The limitations to the synthetic possibilities of reactor-produced fluoride- 18 become manifest in the last part of the thesis. An application to the synthesis of labelled aliphatic fluoro amino acids has appeared to be unsuccessful as yet, although some other synthetic approaches can be indicated. Seven journal articles (for which see the availability note) are used to compose the four chapters and three appendices. The connecting text gives a survey of known 18 F-compounds and methods for preparing such compounds. (Auth.)

  13. Metabolism-oriented amino acid requirement determination by means of the catabolic rates of 14C- and 15N-labelled lysine under maintenance

    International Nuclear Information System (INIS)

    Simon, O.; Bergner, H.; Adam, K.

    1977-01-01

    Male Wistar rats (of 60 g live weight) allotted in 10 groups were fed diets with gradually increasing lysine levels ranging from 1.4 to 7.4 g lysine/16 g N. Feed intake was restricted so much that the experimental animals did not change their live weights during the last 3 days of the 8-day experimental period. On the 7the experimental day, 4 animals of each group were injected, i. p. 14 C-L-lysine, the 14 CO 2 -excretion being subsequently measured over a period of 2 hours. On the next day, 6 animals of each group were applied an i. p. injection of 15 N-L-lysine, the urine being collected over the following 24-hour period to measure the 15 N-frequency. Applying both labelling methods, an increased catabolisation of the amino acid was observed after the metabolically necessary lysine requirement had been covered. The methods are very sensitive and revealed, under the experimental conditions chosen, a lysine requirement coverage of about 3 g lysine/16 g N. The possibility of using also 15 N-labelled compounds in the metabolism-oriented amino acid requirement determination is likely to facilitate the transfer of the methodology to farm animals would thus allow to study the amino acid requirement of man. The metabolism-oriented amino acid requirement determination will likewise allow to estimate exact amino acid requirement data under conditions that cannot be rated on the basis of productive yields. (author)

  14. Synthesis of pyridine and isoquinoline labelled with 14C on the nitrogen heterocycle

    International Nuclear Information System (INIS)

    Robveille, Jacques

    1985-01-01

    This research thesis addresses the synthesis of derivatives of pyridine and isoquinoline labelled with carbon 14 ( 14 C) in the nitrogenated heterocycle as these compounds are of biological and pharmacological interest. The author aimed at developing rather general synthesis schemes which could be easily applied to the synthesis of radioactive compounds, and could produce, through a given synthesis way, the largest as possible family of differently substituted compounds. Different sources for labelled pyridine and isoquinoline have been used: dioxo-1,5 or their corresponding dioxins, substituted pentadienoic acids, derivatives of acrylic acid, and derivatives of cinnamic acid. Thus, three different synthesis processes have been developed to obtain 14 C labelled pyridine, and one of them is applied to the preparation of 14 C labelled isoquinoline. These synthesis processes can have a very general application, and allow different 14 C labelling positions to be envisaged. The possibility to obtain the same compounds but labelled with tritium can also be envisaged to obtain much higher specific activities [fr

  15. Spin-polarized spin excitation spectroscopy

    International Nuclear Information System (INIS)

    Loth, Sebastian; Lutz, Christopher P; Heinrich, Andreas J

    2010-01-01

    We report on the spin dependence of elastic and inelastic electron tunneling through transition metal atoms. Mn, Fe and Cu atoms were deposited onto a monolayer of Cu 2 N on Cu(100) and individually addressed with the probe tip of a scanning tunneling microscope. Electrons tunneling between the tip and the substrate exchange energy and spin angular momentum with the surface-bound magnetic atoms. The conservation of energy during the tunneling process results in a distinct onset threshold voltage above which the tunneling electrons create spin excitations in the Mn and Fe atoms. Here we show that the additional conservation of spin angular momentum leads to different cross-sections for spin excitations depending on the relative alignment of the surface spin and the spin of the tunneling electron. For this purpose, we developed a technique for measuring the same local spin with a spin-polarized and a non-spin-polarized tip by exchanging the last apex atom of the probe tip between different transition metal atoms. We derive a quantitative model describing the observed excitation cross-sections on the basis of an exchange scattering process.

  16. Evaluation of labelling conditions, quality control and biodistribution study of 99mTc-5-aminolevulinic acid (5-ALA). A potential liver imaging agent

    International Nuclear Information System (INIS)

    Kalim Ullah Khan; Mohammad Rafi; Samina Roohi; Rizwana Zahoor; Zafar Iqbal; Mushtaq Ahmad

    2014-01-01

    Labelling of 5-aminolevulinic acid (5-ALA) with 99m Tc was achieved by using SnCl 2 ·2H 2 O as reducing agent. Radiochemical purity and labelling efficiency was determined by instant thin layer chromatography/paper chromatography. Efficiency of labelling was dependent on many parameters such as amount of ligand, reducing agent, pH, and time of incubation. 99m Tc labelled 5-ALA remained stable for 24 h in human serum. Tissue biodistribution of 99m Tc-5-ALA was evaluated in Sprague-Dawley rats. Biodistribution study (% ID/g) in rats revealed that 99m Tc-5-ALA was accumulated significantly in liver, spleen, stomach and intestine after half hour, 4 and 24 h. Significant activity was noted in bladder and urine at 4 h. High liver uptake of 99m Tc-5-ALA makes it a promising liver imaging agent. (author)

  17. Automated no-carrier-added synthesis of [1-11C]-labeled D- and L-enantiomers of lactic acid

    International Nuclear Information System (INIS)

    Drandarov, Konstantin; Schubiger, P. August; Westera, Gerrit

    2006-01-01

    The first purely chemical method for automated no-carrier-added synthesis of [1- 11 C]-labeled D(R)- and L(S)-2-hydroxypropanoic acid (lactic acid) was developed for experimental neurophysiology studies and position emission tomography (PET) diagnosis. Starting from sodium 1-hydroxyethanesulfonate and [ 11 C]HCN (trapped as [ 11 C]KCN) the intermediate DL-(R,S)-[1- 11 C]-2-hydroxypropanenitrile was prepared. Its rapid acid hydrolysis gave DL-(R,S)-[1- 11 C]lactic acid, which was isolated by preparative reversed phase HPLC and automatically injected on a second preparative C 18 HPLC column coated with a chiral selector, where both [1- 11 C]lactic acid enantiomers were separated by chiral ligand-exchange chromatography. Two novel chiral selectors for HPLC enantiomeric separation of α-hydroxy acids, namely D(R)- or L(S)-2-amino-3-methyl-3-(5-phenylpentylsulfanyl)-butanoic acid were utilized for the preparative HPLC separation of the [1- 11 C]lactic acid enantiomers. The preparation of the selectors and the coating procedure for the manufacturing of the preparative chiral HPLC columns are described. A highly efficient trap for [ 11 C]HCN is presented. The whole radiosynthesis is automated, takes about 45 min and leads to more than 80% decay corrected overall radiochemical yield of each enantiomer (up to 2.5 GBq) with over 99% radiochemical, chemical and enantiomeric purity. The specific activity at the end of the synthesis is about 400 GBq/μmol

  18. Syntheses of 2-nitroimidazole derivatives conjugated with 1,4,7-triazacyclononane-N,N'-diacetic acid labeled with F-18 using an aluminum complex method for hypoxia imaging.

    Science.gov (United States)

    Hoigebazar, Lathika; Jeong, Jae Min; Lee, Ji-Youn; Shetty, Dinesh; Yang, Bo Yeun; Lee, Yun-Sang; Lee, Dong Soo; Chung, June-Key; Lee, Myung Chul

    2012-04-12

    Hypoxia imaging is important for diagnosis of ischemic diseases, and thus various (18)F-labeled radiopharmaceuticals have been developed. However, (18)F-labeling requires multistep procedures including azeotropic distillation, which is complicated and difficult to automate. Recently, (18)F-labeling method using Al-F complex in aqueous solution was devised that offered a straightforward (18)F-labeling procedure. We synthesized nitroimidazole derivatives conjugated with 1,4,7-triazacyclononane-1,4-diacetic acid (NODA) that can be labeled with (18)F using Al-F complex and examined their radiochemistries, in vitro and in vivo biological properties, and animal PET imaging characteristics. We found that the synthesized derivatives have excellent (18)F-labeling efficiencies, high stabilities, specific uptakes in cultured hypoxic tumor cells, and high tumor to nontumor ratios in xenografted mice. Furthermore, the derivatives were labeled with (18)F in a straightforward manner within 15 min at high labeling efficiencies and radiochemical purities. In conclusion, (18)F-labeled NODA-nitroimidazole conjugates were developed and proved to be promising hypoxia PET agents. © 2012 American Chemical Society

  19. Adjunctive low-dose docosahexaenoic acid (DHA) for major depression: An open-label pilot trial.

    Science.gov (United States)

    Smith, Deidre J; Sarris, Jerome; Dowling, Nathan; O'Connor, Manjula; Ng, Chee H

    2018-04-01

    Whilst the majority of evidence supports the adjunctive use of eicosapentaenoic acid (EPA) in improving mood, to date no study exists using low-dose docosahexaenoic acid (DHA) alone as an adjunctive treatment in patients with mild to moderate major depressive disorder (MDD). A naturalistic 8-week open-label pilot trial of low-dose DHA, (260 mg or 520 mg/day) in 28 patients with MDD who were non-responsive to medication or psychotherapy, with a Hamilton Depression Rating Scale (HAM-D) score of greater than 17, was conducted. Primary outcomes of depression, clinical severity, and daytime sleepiness were measured. After 8 weeks, 54% of patients had a ≥50% reduction on the HAM-D, and 45% were in remission (HAM-D ≤ 7). The eta-squared statistic (0.59) indicated a large effect size for the reduction of depression (equivalent to Cohen's d of 2.4). However confidence in this effect size is tempered due to the lack of a placebo. The mean score for the Clinical Global Impression Severity Scale was significantly improved by 1.28 points (P depression.

  20. Vesicle interactions with polyamino acids and antibody: in vitro and in vivo studies

    International Nuclear Information System (INIS)

    Dunnick, J.K.; McDougall, I.R.; Aragon, S.; Goris, M.L.; Kriss, J.P.

    1975-01-01

    Artificial spherules or vesicles of 900 A in diameter formed from phosphatidylcholine and gangliosides and enclosing /sup 99m/TcO 4 - (standard preparation) survive intact in the circulation of the mouse. Polyamino acids and protein have been incorporated into and onto the vesicles; such vesicles remain intact as determined by diffusion dialysis studies and by electron paramagnetic resonance studies of vesicles enclosing spin label. In studying the distribution of polyamino acid-vesicles and protein vesicles in vivo, it was found that the latter distribute differently from standard vesicles or free protein alone whereas aromatic polyamino acid-vesicles concentrate in the liver and spleen to a greater extent than standard vesicles. The permeability and stability characteristics of vesicles may be preserved when they are modified by the addition of protein or polyamino acids and that such modification of vesicles may be associated with an alteration of their fate in vivo. The potential exists to use vesicles as carriers of radiopharmaceuticals and other drugs and to direct the vesicles preferentially to tissue targets in vivo. (U.S.)