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Sample records for 11c labeled erlotinib

  1. Preparation of 11C labelled tamoxifen

    1999-01-01

    The syntheses and HPLC analysis of N-desmethyltamoxifen and carbon-11labelled tamoxifen are described. In order to obtain the N-desmethyltamoxifen,tamoxifencitrate was first converted to tamoxifen free base.N-desmethyltamoxifen wasprepared by reacting tamoxifen free base with 1-chloroethyl-chloroformate(ACE.Cl).For 11C labeling, N-desmethyltamoxifen was heated with 11Cmethyl iodide for 10min at 130℃,and the 11Clabelled compound was purifiedby HPLC on a μBonapak TM C18 column.Injectable 11C-tamoxifen was obtained within 50~60min from EOB (end-of-bombardment) with a labeling yield of 60%~70%.

  2. Quantitative Analysis of [11C]-Erlotinib PET Demonstrates Specific Binding for Activating Mutations of the EGFR Kinase Domain

    J. Ryan Petrulli

    2013-12-01

    Full Text Available Activating mutations of the epidermal growth factor receptor (EGFR occur in multiple tumor types, including non-small cell lung cancer (NSCLC and malignant glioma, and have become targets for therapeutic intervention. The determination of EGFR mutation status using a noninvasive, molecular imaging approach has the potential for clinical utility. In this study, we investigated [11C]-erlotinib positron emission tomography (PET imaging as a tool to identify activating mutations of EGFR in both glioma and NSCLC xenografts. Radiotracer specific binding was determined for high and low specific activity (SA [11C]-erlotinib PET scans in mice bearing synchronous human cancer xenografts with different EGFR expression profiles (PC9, HCC827, U87, U87 ΔEGFR, and SW620. Although xenograft immunohistochemistry demonstrated constitutive EGFR phosphorylation, PET scan analysis using the Simplified Reference Tissue Model showed that only kinase domain mutant NSCLC (HCC827 and PC9 had significantly greater binding potentials in high versus low SA scans. Xenografts with undetectable EGFR expression (SW620, possessing wild-type EGFR (U87, and expressing an activating extracellular domain mutation (U87 ΔEGFR were indistinguishable under both high and low SA scan conditions. The results suggest that [11C]-erlotinib is a promising radiotracer that could provide a novel clinical methodology for assessing EGFR and erlotinib interactions in patients with tumors that harbor EGFR-activating kinase domain mutations.

  3. Solid support for [11C]cyanide labelling of radiopharmaceuticals

    [11C]HCN plays a major role in synthesis of 11C-labelled organic radiopharmaceuticals because of its on-line availability as a primary precursor of Carbon-11. [11C]HCN is usually trapped in 0.5-1.0 ml of 0.1 M NaOH or KOH solution for the synthesis of organic labelled compounds. Though [11C]HCN in 0.1 M base can be utilized for labelling base resistant organic compounds, substrates with esters, amide like functional groups cannot be labelled using this method due to the instability of these groups in basic medium. The authors report a novel approach for trapping no-carrier-added [11C]HCN on a silica gel support and its incorporation into model compounds

  4. Adaptation of an automated [11C]methylation system for the loop labeling method using [11C]methyl triflate

    An automated system for preparation of 11C-methylated compounds from [11C]methyl iodide, manufactured by Sumitomo Heavy Industries Ltd., was adapted for the loop labeling method using [11C]methyl triflate. Two 2-way valves on an exchangeable tray were replaced with 3-way valves and a furnace for heating an AgOTf column at 200 deg C was added. The automated system successfully produced [11C]raclopride and [11C]N-methyl-3-piperidyl benzilate in 0.96-1.1 GBq and 1.0-1.3 GBq, respectively, at 40 min after the end of bombardment. (author)

  5. Synthesis of some 11C-labelled alkaloids

    Using (11C)-methyl iodide in N-alkylation reactions in dimethylformamide (DMF), the alkaloids N-(11C-methyl)-morphine, N-(11C-methyl)-codeine, 6-N(methyl)-9, 10-dihydroergotamine, 6-N-(11C-methyl)-bromocriptine and N-(11C-methyl)-nicotine have been synthesized in radiochemical yields of 50-95%, within 5-10 min of introducing (11C)-methyl iodide into the reaction vial. (11C)-Methyl iodide was obtained within 4-7 min from (11C)-carbon dioxide prepared by the 14N(p,α)11C reaction. (Authors)

  6. Chemical and enzymatic approaches for 11C-labelled octopamine synthesis using hydrogen [11C]cyanide

    Octopamine, the β-hydroxy derivative of tyramine, has been the objects of growing interest as biogenic trace amine. Studies using [3H]-labelled p- and m-octopamine have shown that they are both taken up in noradrenergic nerve terminals, accumulated in storage vesicles, and released together with noradrenaline on stimulation. p- and m-[11C]Octopamine have been synthesized from H[11C]CN in two-step sequence. Both chemical and enzymatic procedures have been used for the production of [11C]cyanohydrin intermediates as the key step. The enantiomeric composition of the labelled products obtained through the enzymatic process was assayed by analytical HPLC

  7. Synthesis of some /sup 11/C-labelled alkaloids

    Laangstroem, B.; Antoni, G.; Halldin, H.; Svaerd, H.; Bergson, G. (Univ. of Uppsala (Sweden) Inst. of Chemistry)

    1982-01-01

    Using (/sup 11/C)-methyl iodide in N-alkylation reactions in dimethylformamide (DMF), the alkaloids N-(/sup 11/C-methyl)-morphine, N-(/sup 11/C-methyl)-codeine, 6-N(methyl)-9, 10-dihydroergotamine, 6-N-(/sup 11/C-methyl)-bromocriptine and N-(/sup 11/C-methyl)-nicotine have been synthesized in radiochemical yields of 50-95%, within 5-10 min of introducing (/sup 11/C)-methyl iodide into the reaction vial. (/sup 11/C)-Methyl iodide was obtained within 4-7 min from (/sup 11/C)-carbon dioxide prepared by the /sup 14/N(p,..cap alpha..)/sup 11/C reaction.

  8. Syntheses of 18F-labeled reduced haloperidol and 11C-labeled reduced 3-N-methylspiperone

    18F-Labeled reduced haloperidol and 11C-labeled reduced 3-N-methylspiperone were synthesized in a convenient and quantitative one step reduction from 18F-labeled haloperidol and 11C-labeled N-methylspiperone, respectively. Both products were purified by semipreparative HPLC and were obtained at high specific activity and radiochemical purity. (author)

  9. 11C-labeling of indolealkylamine alkaloids and the comparative study of their tissue distributions

    Five indolealkylamines (N,N-dimethyltryptamine, N-methyltryptamine, bufotenine, O-methylbufotenine, N,N,N-trimethyltryptamine iodide) were labeled with 11C by use of 11CH3I. The labeled compounds were synthesized with a radiochemical yield of 2-50% (based on trapped 11CH3I) in 20-35 min with radiochemical purities of more than 92%. The tissue distributions of these labeled compounds were investigated in rats. In all cases, the accumulations in the liver, lung and small intestine were high. [11C]DMT and [11C]OMB also accumulated to a large extent in the brain, where their accumulation was retained. Brain uptake of three other radiopharmaceuticals was low. [11C]DMT is the radiopharmaceutical of choice for the study of the serotonin action mechanism in the brain, because it has the highest radiochemical yield and the highest brain uptake of these 11C-labeled compounds. (author)

  10. Fixation, retention and exhalation of carrier-free 11C-labelled carbon monoxide by man

    Carrier-free 11C-labelled carbon monoxide was produced by proton irradiation of a nitrogen gas flow target via the 14N(p,α)11C process followed by on-line reduction of the predominantly formed 11C-carbon dioxide with a yield of 0.4 mCi/μAmin. After appropriate quality control about 2 mCi of carrier-free 11C-carbon monoxide in 500 ml of nitrogen gas were inhaled by test subjects in one breath. The 11C-activity distribution was then followed in vivo by scanning above thorax, head, liver, thigh and os sacrum; simultaneously the 11C-activity of the blood was also followed by batch measurement. The data indicate that part of the 11C-activity migrates from the blood into the intercellular space, while another part is exhaled. The 11C-activity leaves the individual organs with a biological half-life ranging from about 120 to 200 min, a time which is short as compared to the one observed for 51Cr-labelled erythrocytes. A radio gas chromatographic analysis of the exhaled air showed that the 11C-activity leaves the body exclusively in the form of 11C-labelled carbon monoxide. Consequently, metabolism of the 11CO into 11Co2 or other compounds can be excluded. (orig.)

  11. Synthesis of O-[11C]acetyl CoA, O-[11C]acetyl-L-carnitine, and L-[11C]carnitine labelled in specific positions, applied in PET studies on rhesus monkey

    The syntheses of L-carnitine, O-acetyl CoA, and O-acetyl-L-carnitine labelled with 11C at the 1- or 2-position of the acetyl group or the N-methyl position of carnitine, using the enzymes acetyl CoA synthetase and carnitine acetyltransferase, are described. With a total synthesis time of 45 min, O-[1-11C]acetyl CoA and O-[2-11C]acetyl CoA was obtained in 60-70% decay-corrected radiochemical yield, and O-[1-11C]acetyl-L-carnitine and O-[2-11C]acetyl-L-carnitine in 70-80% yield, based on [1-11C]acetate or [2-11C]acetate, respectively. By an N-methylation reaction with [11C]methyl iodide, L-[methyl-11C]carnitine was obtained within 30 min, and O-acetyl-L-[methyl-11C]carnitine within 40 min, giving a decay-corrected radiochemical yield of 60% and 40-50%, respectively, based on [11C]methyl iodide. Initial data of the kinetics of the different 11C-labelled L-carnitine and acetyl-L-carnitines in renal cortex of anaesthetized monkey (Macaca mulatta) are presented

  12. Synthesis of O-[{sup 11}C]acetyl CoA, O-[{sup 11}C]acetyl-L-carnitine, and L-[{sup 11}C]carnitine labelled in specific positions, applied in PET studies on rhesus monkey

    Jacobson, Gunilla B.; Watanabe, Yasuyoshi; Valind, Sven; Kuratsune, Hirohiko; Laangstroem, Bengt

    1997-07-01

    The syntheses of L-carnitine, O-acetyl CoA, and O-acetyl-L-carnitine labelled with {sup 11}C at the 1- or 2-position of the acetyl group or the N-methyl position of carnitine, using the enzymes acetyl CoA synthetase and carnitine acetyltransferase, are described. With a total synthesis time of 45 min, O-[1-{sup 11}C]acetyl CoA and O-[2-{sup 11}C]acetyl CoA was obtained in 60-70% decay-corrected radiochemical yield, and O-[1-{sup 11}C]acetyl-L-carnitine and O-[2-{sup 11}C]acetyl-L-carnitine in 70-80% yield, based on [1-{sup 11}C]acetate or [2-{sup 11}C]acetate, respectively. By an N-methylation reaction with [{sup 11}C]methyl iodide, L-[methyl-{sup 11}C]carnitine was obtained within 30 min, and O-acetyl-L-[methyl-{sup 11}C]carnitine within 40 min, giving a decay-corrected radiochemical yield of 60% and 40-50%, respectively, based on [{sup 11}C]methyl iodide. Initial data of the kinetics of the different {sup 11}C-labelled L-carnitine and acetyl-L-carnitines in renal cortex of anaesthetized monkey (Macaca mulatta) are presented.

  13. Carbon-11 labelling of an inhibitor of acetylcholinesterase: [11C]physostigmine

    Physostigmine, an alkaloid from calabar bean is a strong inhibitor of acetylcholinesterase and has been used clinically in the treatment of glaucoma, atropine intoxication, myasthenia gravis and more recently, in experimental trials in Alzheimer's disease. In order to study the AChE activity in the brain by positron emission tomography, we have undertaken the labelling of physostigmine with carbon-11. The synthesis involves the reaction of [11C]methylisocyanate with eseroline. [11C]Methylisocyanate was obtained by heating [11C]acetylchloride with tetrabutylammonium azide in toluene. The synthesis of [11C]CH3COC1 involves the carbonation of methylmagnesium bromide in THF with cyclotron produced [11C]carbon dioxide and the addition of phthaloyl dichloride. The [11C]methylisocyanate is distilled into a solution of eseroline in ether with a small piece of sodium. After 10 minutes at 25oC, the solution is purified by HPLC and the appropriate fraction collected. Starting with 55.5 GBq (1.5 Ci) of [11C]carbon dioxide, 0.92-1.48 GBq (25-40 mCi) of [11C]Physostigmine are obtained 57 minutes after EOB. (author)

  14. Carbon-11 labelling of an inhibitor of acetylcholinesterase: [[sup 11]C]physostigmine

    Bonnot-Lours, S.; Crouzel, C.; Prenant, C.; Hinnen, F. (CEA, 91 - Orsay (France). Service Hospitalier Frederic Joliot)

    1993-01-01

    Physostigmine, an alkaloid from calabar bean is a strong inhibitor of acetylcholinesterase and has been used clinically in the treatment of glaucoma, atropine intoxication, myasthenia gravis and more recently, in experimental trials in Alzheimer's disease. In order to study the AChE activity in the brain by positron emission tomography, we have undertaken the labelling of physostigmine with carbon-11. The synthesis involves the reaction of [[sup 11]C]methylisocyanate with eseroline. [[sup 11]C]Methylisocyanate was obtained by heating [[sup 11]C]acetylchloride with tetrabutylammonium azide in toluene. The synthesis of [[sup 11]C]CH[sub 3]COC1 involves the carbonation of methylmagnesium bromide in THF with cyclotron produced [[sup 11]C]carbon dioxide and the addition of phthaloyl dichloride. The [[sup 11]C]methylisocyanate is distilled into a solution of eseroline in ether with a small piece of sodium. After 10 minutes at 25[sup o]C, the solution is purified by HPLC and the appropriate fraction collected. Starting with 55.5 GBq (1.5 Ci) of [[sup 11]C]carbon dioxide, 0.92-1.48 GBq (25-40 mCi) of [[sup 11]C]Physostigmine are obtained 57 minutes after EOB. (author).

  15. Dosimetry of D- and L-enantiomers of 11C-labeled tryptophan and valine

    The authors have previously reported the radiation dosimetry of 11C-labeled DL-tryptophan and DL-valine, as well as clinical pancreatic imaging studies with these agents. Because of significant uptake in both normal pancreas and in pancreatic tumors (thought to be due to the presence of the D-enantiomer), differential diagnosis of pancreatic carcinoma was not feasible. High-performance liquid chromatographic (HPLC) methods were developed for rapid resolution of 11C-labeled DL-tryptophan and DL-valine. Radiation dose estimates to the various organs in man were calculated for the D- and L-enantiomers of 11C-labeled tryptophan and valine, based on tissue distribution data in rats. The dose estimates were sufficiently low that 20-mCi doses of each of the enantiomeric amino acids were approved by the FDA for intravenous administration to humans. 21 references, 3 tables

  16. Dosimetry of D- and L-enantiomers of 11C-labeled tryptophan and valine

    We have previously reported the radiation dosimetry of 11C-labeled DL-tryptophan and DL-valine, as well as clinical pancreatic imaging studies with these agents. Because of significant uptake in both normal pancreas and in pancreatic tumors (thought to be due to the presence of the D-enantiomer), differential diagnosis of pancreatic carcinoma was not feasible. High-performance liquid chromatographic (HPLC) methods were developed for rapid resolution of 11C-labeled DL-tryptophan and DL-valine. Radiation dose estimates to the various organs in man were calculated for the D- and L-enantiomers of 11C-labeled tryptophan and valine, based on tissue distribution data in rats. The dose estimates were sufficiently low that 20-mCi doses of each of the enantiomeric amino acids were approved by the FDA for intravenous administration to humans. 21 refs., 3 tabs

  17. Direct synthesis and application of 11C and 13N labelled organic compounds by accelerator

    In the nuclear medicine, the compounds labelled by 11C and 13N, short-lived nuclide, have been used as a diagnostic reagent for PET. We found 80% yield of 11C labelled organic compounds were synthesized by direct irradiation of high energy γ ray to carbon cluster( a kind of fullerene) and other organic reagents. The Electron Linac (Tohoku University) and SF Cyclotron (Tokyo University) were used. By the Electron Linac, the samples were irradiated by Bremsstrahlung generated from platinum plate irradiated with 30 MeV beam using 12C(γ,n)11C. On the SF cyclotron, the mixture between sample and boron was irradiated by 12 MeV proton using 11B(p,n)11C. Many reagents were isolated and refined by a preparative HPLC (high-performance liquid chromatography). Oxine was used as a model compound and experimental results are shown. 54% 11C labeled compounds isolated by sublimation were oxine. This method is very simple and easy. Accordingly, we can use the method to the very complex compound. (S.Y.)

  18. Synthesis of the 11C-labelled β-adrenergic receptor ligands atenolol, metoprolol and propanolol

    The 11C-labelled β-adrenergic receptor ligands atenolol 1, metoprolol 2 and propranolol 3 have been synthesized by an N-alkylation reaction using [2-11C]isopropyl iodide. The labelled isopropyl iodide was prepared in a one-pot reactor system from [11C]carbon dioxide and obtained in 40% radiochemical yield within 14 min reaction time. The total reaction times for compounds 1-3, counted from the start of the isopropyl iodide synthesis and including purification were 45-55 min. The products were obtained in 5-15% radiochemical yields and with radiochemical purities higher than 98%. The specific activity ranged from 0.4 to 4 GBq/μmol. In a typical experiment starting with 4 GBq around 75 MBq of product was obtained. (author)

  19. Synthesis of the sup 11 C-labelled. beta. -adrenergic receptor ligands atenolol, metoprolol and propanolol

    Antoni, G.; Ulin, J.; Laangstroem, B. (Uppsala Univ. (Sweden). Dept. of Organic Chemistry)

    1989-01-01

    The {sup 11}C-labelled {beta}-adrenergic receptor ligands atenolol 1, metoprolol 2 and propranolol 3 have been synthesized by an N-alkylation reaction using (2-{sup 11}C)isopropyl iodide. The labelled isopropyl iodide was prepared in a one-pot reactor system from ({sup 11}C)carbon dioxide and obtained in 40% radiochemical yield within 14 min reaction time. The total reaction times for compounds 1-3, counted from the start of the isopropyl iodide synthesis and including purification were 45-55 min. The products were obtained in 5-15% radiochemical yields and with radiochemical purities higher than 98%. The specific activity ranged from 0.4 to 4 GBq/{mu}mol. In a typical experiment starting with 4 GBq around 75 MBq of product was obtained. (author).

  20. Labelling of polysaccharides using [{sup 11}C]cyanogen bromide. In vivo and in vitro evaluation of {sup 11}C-hyaluronan uptake kinetics

    Westerberg, Goeran; Bergstroem, Mats; Gustafson, Stefan; Lindqvist, Ulla; Sundin, Anders; Laangstroem, Bengt

    1995-02-01

    A method for the {sup 11}C-labelling of polysaccharides in high specific radioactivity is described. Dextran and hyaluronan were treated with [{sup 11}C]cyanogen bromide in aqueous solution at pH 11.5 to give 30-47% radiochemical yields with higher than 98% radiochemical purity in synthesis times of 24-26 min counted from the end of bombardment. Specific radioactivities at the end of synthesis ranged from 0.12 to 3.1 Ci/{mu}mol. The biodistribution kinetics of [{sup 11}C]hyaluronan injected intravenously was studied in rats by means of positron emission tomography, showing a rapid and displaceable uptake in liver. Uptake and displacement of [{sup 11}C]hyaluronan was also demonstrated in cultured rat liver endothelial cells.

  1. Labeling of complex molecules with 18F, 13N, and 11C

    The overall objective during the period covered by this report was to develop a broad spectrum of radiopharmaceuticals labeled with short-lived cyclotron positron emitters, 11C, 13N and 18F. The goals of the program during the last year were: (1) to complete the modular automated system for important precursor production - formaldehyde, methyliodide, cyanide; (2) to perform animal studies with the 18F-glucose analogues 2FDG and 3FDG and measure the constants for both agents in different animals; and (3) to initiate the development of new fatty acid analogues for the myocardial imaging and metabolism. As part of a collaboration with other groups seeking new agents for myocardium and brain, 9-/sup 123m/Te-telluriumheptadecanoic acid as a myocardial imaging agent was studied. This compound could be used for designing new fatty acid analogues labeled with 11C and 18F that stay in the myocardium because of metabolic inhibition

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

    The synthesis of 1- and 3-11C-labelled L-lactic acid from the corresponding racemic 1- or 3-11C-labelled alanine using a multi-enzymatic reaction route, is presented. DL-[1-11C]Alanine was synthesised by reacting sodium 1-hydroxy-ethyl sulfite with hydrogen [11C]cyanide, obtained from [11C]carbon dioxide, and ammonia followed by acid hydrolysis. DL-[3-11C]-Alanine was synthesised by a methylation of a glycine derivative, N-(diphenylmethylene)-glycine tert-butyl ester, with [11C]methyl iodide, obtained from [11C]carbon dioxide, and subsequent hydrolysis. The racemic 1- or 3-11C-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 [11C]carbon dioxide. The decay corrected radiochemical yields were ca. 80% for L-[1-11C]lactic acid, based on hydrogen cyanide, and ca. 60% for L-[3-11C]lactic acid, based on carbon dioxide. The radiochemical purities were higher than 99% analysed by HPLC. (author)

  3. Synthesis of sup 11 C-labeled citalopram, a selective serotonin uptake inhibitor

    Ram, Siya (Duke Univ., Durham, NC (USA). Dept. of Radiology)

    1990-01-01

    A procedure for labeling the novel serotonin uptake inhibitor, citalopram (1-(3-dimethylamino)propyl-1-(p-fluorophenyl)-5-phthalancarbonitrile, Lu 10-171 ), with the positron emitting radionuclide {sup 11}C (t{sub 1/2} = 20.4 min) has been developed, in order to permit the pharmacokinetics of this compound to be studied in man. The procedure involves the reaction of ({sup 11}C)iodomethane with desmethylcitalopram in acetone in the presence of sodium hydroxide base at 65deg for 8-10 min; this was followed by purification by a column which contained, in series silica gel and basic alumina, and produces no carrier added ({sup 11}C)citalopram in radiochemical yield (18-66% at EOB) and radiochemical purity (>95%). The specific activity of ({sup 11}C)citalopram was 2.52 x 10{sup 3}-16.06 x 10{sup 3} GBq/mmol (68-434 Ci/mmol) at the end of synthesis. (author).

  4. The use of [11C]diazomethane for labelling a calcium channel antagonist: PN 200-110 (Isrodipine)

    PN 200-110 (Isrodipine), a calcium channel antagonist, was labelled with 11C (t1/2 20.4 min) by a reaction between [11C]diazomethane and the carboxyl precursor. The [11C]CH2N2 is prepared in two stages from [11C]CH4: [11C]CH4→[11C]CHCl3→[11C]CH2N2. When a mixture of nitrogen (95%) and hydrogen (5%) is irradiated with 20 MeV protons (30 min, 30 μ A), 60-80 mCi of product are prepared and purified with HPLC. The 11C product is ready for medical use within 35 min of the end of bombardment. (author)

  5. The preparation of 11C-labelled fluoromethane for the study of regional cerebral blood flow using positron emission tomography

    Fluoromethane, previously labelled with 18F and used as a tracer in the measurement of regional cerebral blood flow, was 11C-labelled by the reaction of 11C-methyl iodide with tetraethylammonium fluoride. Sufficient quantities of radiotracer were prepared with a minimum amount of handling from 15 min target irradiations in the 14N(p, α)11C reaction. Total synthesis time was 25 min from end-of-bombardment, allowing serial blood flow measurements 30 min apart. The use of 11C-fluoromethane as a cerebral blood flow tracer in positron emission tomography is discussed. (orig.)

  6. Modulation of organ uptake of {sup 11}C-labelled L-DOPA

    Bergstroem, Mats; Lu Li; Marquez, Marcela; Fasth, Karl Johan; Bjurling, Peter; Watanabe, Yasuyoshi; Eriksson, Barbro; Laangstroem, Bengt

    1997-01-01

    The present study was undertaken to investigate if pretreatment with pharmacological agents could change the organ uptake of {sup 11}C-labelled L-DOPA, and especially if the urinary excretion could be decreased. L-[{beta}-{sup 11}C]DOPA was injected IV into unanesthetized Sprague-Dawley rats. After 20 min the rats were decapitated and organs taken out for radioactivity measurements. The uptake in the organs was investigated in animals only given the tracer, and in animals pretreated with drugs such as decarboxylase inhibitors carbidopa and benserazide as well as the monoamine oxidase inhibitors deprenyl, clorgyline, and the COMT inhibitor OR-486. A marked decrease in the urinary radioactivity was observed after carbidopa and benserazide administration. HPLC analysis revealed that under native conditions the major part of urinary radioactivity existed as dopamine, which was eliminated by the decarboxylase inhibitors. After pretreatment with the COMT inhibitor OR-486, the radioactivity uptake in the pancreas increased fourfold as compared to non-treated animals. HPLC analysis showed that this correlated with a marked increase in radiolabelled DOPAC. In the other organs and with the other drugs, only small effects were observed. With L-[{beta}-{sup 11}C]fluoroDOPA as a tracer, similar results were observed although the increase in the pancreas by OR-486 had a lower magnitude. These studies suggest that it might be possible to improve the diagnostic ratio of L-[{beta}-{sup 11}C]DOPA or L-[{sup 18}F]fluoroDOPA in whole-body PET studies by pretreating the patient with decarboxylase inhibitor for reducing the urinary excretion and potentially increase the target organ uptake by COMT inhibition.

  7. Modulation of organ uptake of 11C-labelled L-DOPA

    The present study was undertaken to investigate if pretreatment with pharmacological agents could change the organ uptake of 11C-labelled L-DOPA, and especially if the urinary excretion could be decreased. L-[β-11C]DOPA was injected IV into unanesthetized Sprague-Dawley rats. After 20 min the rats were decapitated and organs taken out for radioactivity measurements. The uptake in the organs was investigated in animals only given the tracer, and in animals pretreated with drugs such as decarboxylase inhibitors carbidopa and benserazide as well as the monoamine oxidase inhibitors deprenyl, clorgyline, and the COMT inhibitor OR-486. A marked decrease in the urinary radioactivity was observed after carbidopa and benserazide administration. HPLC analysis revealed that under native conditions the major part of urinary radioactivity existed as dopamine, which was eliminated by the decarboxylase inhibitors. After pretreatment with the COMT inhibitor OR-486, the radioactivity uptake in the pancreas increased fourfold as compared to non-treated animals. HPLC analysis showed that this correlated with a marked increase in radiolabelled DOPAC. In the other organs and with the other drugs, only small effects were observed. With L-[β-11C]fluoroDOPA as a tracer, similar results were observed although the increase in the pancreas by OR-486 had a lower magnitude. These studies suggest that it might be possible to improve the diagnostic ratio of L-[β-11C]DOPA or L-[18F]fluoroDOPA in whole-body PET studies by pretreating the patient with decarboxylase inhibitor for reducing the urinary excretion and potentially increase the target organ uptake by COMT inhibition

  8. Synthesis of 11C-labeled Kendine 91, a histone deacetylase inhibitor

    In the present paper, the synthesis of 11C-labeled Kendine 91 (a HDAC inhibitor which has shown in vitro and in vivo activity in HCT 116 and MOLT 4 human cancer cell lines) is described for the first time. The radiosynthesis has been approached by reaction of the non-radioactive precursor 6-((3-(4-hydroxyphenyl)-5-phenyl-1H-pyrrole-2-carboxamide))hexanehydroxamic acid with [11C]CH3I in basic media. Despite the presence of more than one reactive site in the chemical structure of the precursor, acceptable radiochemical yield (8.2±2.1%, decay corrected to the end of bombardment), specific activity (28.2±9.4 GBq/μmol) and radiochemical purity values (>95%) were obtained in reasonably short preparation times (∼40 min). Despite the moderate radiochemical yield, final radioactivity and radioactivity concentration values (1.8±0.3 GBq and 180 MBq/ml, respectively) should be sufficient for putative in vivo studies in animals. - Highlights: ► We labeled Kendine 91 with carbon-11. ► Despite low yields final radioactivity should allow in vivo studies. ► We synthesized the desmethylated precursor using two routes. ► Microwave assisted Paal–Knorr reaction was more efficient than (3+2) cycloaddition.

  9. A generic model for 11C labelled radiopharmaceuticals for imaging receptors in the human brain

    A large number of radiopharmaceuticals labelled with 11C (half-time 0.340 h) are being developed for positron emission tomographic studies of different types of receptor in the human brain. For most of these agents the available biokinetic data are insufficient to construct realistic compound-specific biokinetic models for calculating the internal radiation dose delivered to persons undergoing investigation. A generic model for brain receptor substances that predicts the internal dose with sufficient accuracy for general radiation protection purposes has, therefore, been developed. Biokinetic data for 13 11C radiopharmaceuticals used clinically for imaging different brain receptors indicate that, despite differences in chemical structure, their uptake and retention in the human brain and other tissues is broadly similar. The proposed model assumes instantaneous deposition of 5% of the injected radioactivity in the brain, with the remaining radioactivity being rapidly and uniformly distributed throughout all other tissues. Elimination from all tissues is assumed to occur with a half-time of 2 h. It is further assumed that 75% of the injected 11C is excreted in the urine, and 25% via the gall bladder, with a half-time of 2 h. This model yields an effective dose of 4.5 x 10-3mSv/MBq, with doses of 3.2 x 10-2, 1.7 x 10-2, 8.7 X 10-3, 5.2 x 10-3, and 3.8 x 10-3mGy MBq-1 to the urinary bladder, gall bladder, kidneys, brain and ovaries, respectively. These doses are well within the range of those reported using compound-specific models for the radiopharmaceuticals studied. (author)

  10. Evaluation of myocardial metabolism, with 13N- and 11C-labeled amino acids and positron computed tomography

    To evaluate the utility of labeled L-amino acids (AA) for imaging regional myocardial AA metabolism by positron computed tomography (PCT), the myocardial uptake and clearance of Ala,* Glu, Gln, Asp, Leu tagged with 13N, and of 11C-tagged Asp, and oxaloacetate (Oxal), were examined in 44 experiments at control, during ischemia, and after transaminase inhibition. The myocardial time-activity curves recorded after intracoronary tracer injection had two clearance phases (an early and a late) for all 13N AA, and three (early, intermediate, late) for the two 11C compounds, with significantly different clearance half-times of 18.7 +/- 8.0 (s.d.) sec for the early phase, 141.7 +/- 56.5 sec for the intermediate, and 61.2 +/- 43.5 min for the late phase. The residual fractions ranged from 0.07 to 0.23 in normal myocardium, and consistently increased with ischemia by 0.01-0.07 for 13N-labeled Ala, Glu, Asp, and Leu, but not for 13N Gln and 11C compounds. Transaminase inhibition shortened the half-times of the late phases of 13N-labeled Ala, Glu, Asp, and Leu; had no effect on t1/2 of 13N Gln and 11C Oxal; and resulted in a loss of 11C CO2 production and of the intermediate phase for 11C Asp. On the PCT images, 13N activity from labeled Ala and Glu was not decreased in an ischemic segment despite a significant flow reduction, as demonstrated by 13N NH3 imaging and labeled microspheres. From the results, a three-compartment tracer kinetic model is proposed for the noninvasive quantification of Krebscycle activity, protein synthesis, and metabolic derangements related to ischemia

  11. Kinetics of 11C-labeled opiates in the brain of rhesus monkeys

    Hartvig, P.; Bergstroem, K.; Lindberg, B.; Lundberg, P.O.; Lundqvist, H.; Langstroem, B.; Svaerd, H.; Rane, A.

    1984-07-01

    The regional uptake in the brain of Rhesus monkeys of i.v. administered 11C-labeled morphine, codeine, heroin and pethidine was studied by means of positron emission tomography. The technique measures the sum of parent drug and radiolabeled metabolites. (For the sake of simplicity the drug derived radioactivity is denoted by the drug name.) Morphine had a limited uptake to discrete areas of the brain. The maximum normalized uptake, with respect to dose per kilogram body weight, was about 0.2, i.e., 20% of the calculated activity if the drug had been evenly distributed throughout the body of the monkey. Maximum radioactivity appeared 30 to 45 min after injection. Morphine left the brain slowly with an estimated half-life of more than 2 hr. An area with a normalized uptake of about 1.0 was detected centrally in the lowest horizontal transsection of the skull. The origin of this area was identified as the pituitary. Codeine, heroin and pethidine were taken up to the brain to a larger extent than morphine, with maximum normalized uptakes of 2.6, 4.6 and 6.3, respectively. Maximum radioactivities of these drugs were achieved earlier and the elimination rates were faster than for morphine. Differences in the uptake of these drugs to the brain, as well as differences in time to maximal normalized uptake and rate of disappearance are considered to reflect differences in the lipophilic character between the drugs. Pethidine had the most rapid and extensive uptake followed by heroin, codeine and morphine in order of decreasing lipophilicity.

  12. Kinetics of 11C-labeled opiates in the brain of rhesus monkeys

    The regional uptake in the brain of Rhesus monkeys of i.v. administered 11C-labeled morphine, codeine, heroin and pethidine was studied by means of positron emission tomography. The technique measures the sum of parent drug and radiolabeled metabolites. (For the sake of simplicity the drug derived radioactivity is denoted by the drug name.) Morphine had a limited uptake to discrete areas of the brain. The maximum normalized uptake, with respect to dose per kilogram body weight, was about 0.2, i.e., 20% of the calculated activity if the drug had been evenly distributed throughout the body of the monkey. Maximum radioactivity appeared 30 to 45 min after injection. Morphine left the brain slowly with an estimated half-life of more than 2 hr. An area with a normalized uptake of about 1.0 was detected centrally in the lowest horizontal transsection of the skull. The origin of this area was identified as the pituitary. Codeine, heroin and pethidine were taken up to the brain to a larger extent than morphine, with maximum normalized uptakes of 2.6, 4.6 and 6.3, respectively. Maximum radioactivities of these drugs were achieved earlier and the elimination rates were faster than for morphine. Differences in the uptake of these drugs to the brain, as well as differences in time to maximal normalized uptake and rate of disappearance are considered to reflect differences in the lipophilic character between the drugs. Pethidine had the most rapid and extensive uptake followed by heroin, codeine and morphine in order of decreasing lipophilicity

  13. Inhibition of carnitine-acyl transferase I by oxfenicine studied in vivo with [{sup 11}C]-labeled fatty acids

    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.

  14. Inhibition of carnitine-acyl transferase I by oxfenicine studied in vivo with [11C]-labeled fatty acids

    Methods: Anesthetized pigs were studied with [11C]-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 [11C]-FAs from blood was measured together with the relative distribution of [11C]-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: [11C]-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 [11C]-palmitate serves well to characterize, in vivo, the carnitine-dependent transfer of long-chain FAs

  15. Synthesis and in vivo distribution in rat brain of 11C-labelled N-alkylated ADTN derivatives

    A method for the rapid production and purification of 11C-labelled N-alkylated derivatives of the dopamine agonist 2-amino-6,7-dihydroxytetralin (ADTN) is described. The label is introduced by N-methylation with no-carrier-added 11CH3I of the corresponding secondary amines via their lithium salts. Following systemic injection in rats a uniform distribution of radioactivity in the brain was found for both the labelled 2-(N-methyl-N-n-propylamino)- and 2-(N,N-dimethylamino)-6,7-dihydroxytetralin. (author)

  16. First automatic radiosynthesis of 11C labeled Telmisartan using a multipurpose synthesizer for clinical research use

    Telmisartan, a nonpeptide angiotensin II AT1 receptor antagonist, is an antihypertensive drug. Positron emission tomography (PET) imaging with [11C]Telmisartan is expected to provide information about the whole body pharmacokinetics of telmisartan as well as the transport function of hepatic organic anion-transporting polypeptide (OATP) 1B3. We developed a first automatic preparation system of [11C]Telmisartan to applicable clinical research using a new 11C and 18F multipurpose synthesizer. Two milligrams of precursor (1) in 5 μl of 1 M KOH in 0.5 ml of dimethyl sulfoxide was reacted with [11C]CH3I for 5 min at 120 deg C. The resultant solution was hydrolyzed with 1 M NaOH at 100 deg C for 3 min. The neutralization was carried out with acetic acid, followed by purification with high-performance liquid chromatography. The desired radioactive fraction was collected and solvent was replaced by 10 ml saline containing 0.3 ml of EtOH and 0.5 ml of PEG400, and then passed through a sterile 0.22 μm filter (Millex-GV, Millipore) to a pyrogen-free vial as the final product. The yield of [11C]Telmisartan for clinical research use was 16.8±2.9% end of bombardment (EOB) as decay corrected (n=8, mean ± standard deviation (SD) in 32-36 min. The radiochemical purity of [11C]Telmisartan was >97%, and specific activity was higher than 86.3 MBq/nmol. We succeeded in the first synthesis of [11C]Telmisartan for clinical research use by appropriate quality tests. (author)

  17. Use of transfer function and compartmental analysis to quantify 11C-labelled photoassimilate export from wheat leaves

    Compartmental analysis of tracer loss from a leaf after pulse-labelling with carbon isotopes has often been used to infer the flow of photosynthate through the leaf. Recently, a more general approach has been suggested based upon estimation of the transfer function using data from pulse-labelling as well as continuous labelling experiments. A comparison of these two approaches shows that with the same data set they give equivalent physiological interpretations. The measured decline of 11C activity from a wheat leaf after 11CO2 pulse-labelling was extrapolated by compartmental as well as transfer function analysis. Both methods estimated a 66.4% loss of the initially fixed 11C due to export and respiration. The advantage of transfer function analysis, however, is its applicability to continuous-labelling experiments. The model allows the use of the net photosynthetic rate as the reference (100%) value. Data from continuous-labelling experiments with wheat plants indicate diurnal variations in the export of freshly labelled assimilate of between 32.7% and 43.6% of net photosynthesis. (author)

  18. In vivo kinetics and displacement study of a carbon-11-labeled hallucinogen, N,N-[11C]dimethyltryptamine

    The endogenous hallucinogen, N,N-dimethyltryptamine (DMT), was labeled with carbon-11 and its regional distribution in rat brain studied. [11C]DMT showed higher accumulation in the cerebral cortex, caudate putamen, and amygdaloid nuclei. Studies of the subcellular distribution of [11C]DMT revealed the specific localization in the fractions enriched with serotonin receptors only when a very low dose was injected into rats. The proportions of the radioactivity in receptor-rich fractions were greatly enhanced by pretreatment with the monoamine oxidase inhibitor, pargyline. Specific binding of [11C]DMT to serotonin receptors in dog brain was demonstrated by a positron emission tomographic study in which 5-methoxy-N,N-dimethyltryptamine caused approximately 20% displacement of the radioligand from the receptors. (orig.)

  19. In vivo kinetics and displacement study of a carbon-11-labeled hallucinogen, N,N-(/sup 11/C)dimethyltryptamine

    Yanai, Kazuhiko; Ido, Tatsuo; Ishiwata, Kiichi; Takahashi, Toshihiro; Iwata, Ren; Hatazawa, Jun; Matsuzawa, Taiju

    1986-07-01

    The endogenous hallucinogen, N,N-dimethyltryptamine (DMT), was labeled with carbon-11 and its regional distribution in rat brain studied. (/sup 11/C)DMT showed higher accumulation in the cerebral cortex, caudate putamen, and amygdaloid nuclei. Studies of the subcellular distribution of (/sup 11/C)DMT revealed the specific localization in the fractions enriched with serotonin receptors only when a very low dose was injected into rats. The proportions of the radioactivity in receptor-rich fractions were greatly enhanced by pretreatment with the monoamine oxidase inhibitor, pargyline. Specific binding of (/sup 11/C)DMT to serotonin receptors in dog brain was demonstrated by a positron emission tomographic study in which 5-methoxy-N,N-dimethyltryptamine caused approximately 20% displacement of the radioligand from the receptors.

  20. In vivo kinetics and displacement study of a carbon-11-labeled hallucinogen, N,N-[11C]dimethyltryptamine.

    Yanai, K; Ido, T; Ishiwata, K; Hatazawa, J; Takahashi, T; Iwata, R; Matsuzawa, T

    1986-01-01

    The endogenous hallucinogen, N,N-dimethyltryptamine (DMT), was labeled with carbon-11 and its regional distribution in rat brain studied. [11C]DMT showed higher accumulation in the cerebral cortex, caudate putamen, and amygdaloid nuclei. Studies of the subcellular distribution of [11C]DMT revealed the specific localization in the fractions enriched with serotonin receptors only when a very low dose was injected into rats. The proportions of the radioactivity in receptor-rich fractions were greatly enhanced by pretreatment with the monoamine oxidase inhibitor, pargyline. Specific binding of [11C]DMT to serotonin receptors in dog brain was demonstrated by a positron emission tomographic study in which 5-methoxy-N,N-dimethyltryptamine caused approximately 20% displacement of the radioligand from the receptors. PMID:3489620

  1. Comparative studies of potential cancer biomarkers carbon-11 labeled MMP inhibitors (S)-2-(4'-[11C]methoxybiphenyl-4-sulfonylamino)-3-methylbutyric acid and N-hydroxy-(R)-2-[[(4'-[11C]methoxyphenyl)sulfonyl]benzylamino]-3 -methylbutanamide

    (S)-2-(4'-[11C]methoxybiphenyl-4-sulfonylamino)-3-methylbutyric acid ([11C]MSMA) and N-hydroxy-(R)-2-[[(4'-[11C]methoxyphenyl)sulfonyl]benzylamino]-3- methylbutanamide ([11C]CGS 25966), carbon-11 labeled matrix metalloproteinase (MMP) inhibitors, have been synthesized for evaluation as new potential positron emission tomography (PET) cancer biomarkers. [11C]MSMA was prepared by appropriate precursory droxybiphenyl-4-sulfonylamino)-3-methylbutyric acid tert-butyl ester, which was synthesized in eight steps from amino acid (L)-valine in 39.4% chemical yield. This precursor was labeled by [11C]methyl triflate through O-[11C]methylation method at the hydroxyl position of biphenol under basic conditions, followed by a quick acid hydrolysis and isolated by solid-phase extraction (SPE) purification to produce pure target compound [11C]MSMA in 35-55% radiochemical yield, based on 11CO2, decay corrected to end of bombardment (EOB), and 20-25 min synthesis time. [11C]CGS 25966 was prepared in our previous work starting from amino acid (D)-valine. The biodistribution of [11C]MSMA and [11C]CGS 25966 were determined at 45 min post iv injection in breast cancer animal models MCF-7's transfected with IL-1α implanted athymic mice and MDA-MB-435 implanted athymic mice. The results showed the uptakes of [11C]MSMA and [11C]CGS 25966 in these tumors were 0.95 and 0.42%dose/g in MCF-7's transfected with IL-1α implanted mice, 0.98 and 1.53%dose/g in MDA-MB-435 implanted mice, respectively; the ratios of tumor/muscle (T/M) and tumor/blood (T/B) were 1.21 and 1.09 (T/M, MCF-7's), 0.99 and 0.84 (T/B, MCF-7's), 1.38 and 1.27 (T/M, MDA-MB-435), 1.27 and 1.95 (T/B, MDA-MB-435), respectively. The micro-PET images of [11C]MSMA and [11C]CGS 25966 in both breast cancer athymic mice were acquired for 15 min from a MCF-7's transfected with IL-1α and/or MDA-MB-435 implanted mouse at 45 min post iv injection of 1 mCi of the tracer using a dedicated high resolution (11C]MSMA and [11C]CGS 25966

  2. Design and Synthesis of 11C-Labelled Compound Libraries for the Molecular Imaging of EGFr, VEGFr-2, AT1 and AT2 Receptors: Transition-Metal Mediated Carbonylations Using [11C]Carbon Monoxide

    This work deals with radiochemistry and new approaches to develop novel PET tracers labelled with the radionuclide 11C. Two methods for the synthesis of 11C-labelled acrylamides have been explored. First, [1-11C]-acrylic acid was obtained from a palladium(0)-mediated 11C-carboxylation of acetylene with [11C]carbon monoxide; this could be converted to the corresponding acyl chloride and then combined with benzylamine to form N-benzyl[carbonyl-11C]acrylamide. In the second method, the palladium(0)-mediated carbonylation of vinyl halides with [11C]carbon monoxide was explored. This latter method, yielded labelled acrylamides in a single step with retention of configuration at the C=C double bond, and required less amine compared to the acetylene method. The vinyl halide method was used to synthesize a library of 11C-labelled EGFr-inhibitors in 7-61% decay corrected radiochemical yield via a combinatorial approach. The compounds were designed to target either the active or the inactive form of EGFr, following computational docking studies. The rhodium(I)-mediated carbonylative cross-coupling of an azide and an amine was shown to be a very general reaction and was used to synthesize a library of dual VEGFr-2/PDGFrβ inhibitors that were 11C-labelled at the urea position in 38-78% dc rcy. The angiotensin II AT1 receptor antagonist eprosartan was 11C-labelled at one of the carboxyl groups in one step using a palladium(0)-mediated carboxylation. Autoradiography shows specific binding in rat kidney, lung and adrenal cortex, and organ distribution shows a high accumulation in the intestines, kidneys and liver. Specific binding in frozen sections of human adrenal incidentalomas warrants further investigations of this tracer. Three angiotensin II AT2 ligands were 11C-labelled at the amide group in a palladium(0)-mediated aminocarbonylation in 16-36% dc rcy. One of the compounds was evaluated using in vitro using autoradiography, and in vivo using organ distribution and animal

  3. (-)-N-[11C]propyl-norapomorphine: a positron-labeled dopamine agonist for PET imaging of D2 receptors

    Imaging neuroreceptors with radiolabeled agonists might provide valuable information on the in vivo agonist affinity states of receptors of interest. We report here the radiosynthesis, biodistribution in rodents, and imaging studies in baboons of [11C]-labeled (-)-N-propyl-norapomorphine [(-)-NPA]. (-)-[11C]NPA was prepared by reacting norapomorphine with [11C]propionyl chloride and a lithium aluminum hydride reduction. [11C]Propionyl chloride was prepared by reacting [11C]CO2 with ethylmagnesium bromide, followed by reacting with phthaloyl chloride. The radiochemical yield of (-)-[11C]NPA was 2.5% at end of synthesis (EOS), and the synthesis time was 60 min. The specific activity was 1700±1900 mCi/μmol ( N=7; ranged 110-5200 mCi/μmol at EOS). Rodent biodistribution studies showed high uptake of [11C](-)-NPA in D2 receptor-rich areas, and the striatum/cerebellum ratios were 1.7, 3.4, and 4.4 at 5 min, 30 min, and 60 min postinjection, respectively. Pretreating the animals with haloperidol (1 mg/kg) decreased the striatum/cerebellum ratio at 30 min postinjection to 1.3. (-)-[11C]NPA was also evaluated via baboon positron emission tomography (PET) studies. Under control conditions ( N=4), rapid uptake of the tracer was observed and the striatum/cerebellum ratio reached 2.86±0.15 at 45 min postinjection. Following haloperidol pretreatment (0.2 mg/kg IV), the striatum/cerebellum ratio was 1.29 at 45 min postinjection. The result demonstrated the existence of specific binding of this new tracer to the D2 receptor. To our knowledge, the current finding of a striatum/cerebellum ratio of 2.8 in baboon was the highest reported with a radiolabeled D2 agonist. (-)-[11C]NPA is a promising new D2 agonist PET tracer for probing D2 receptors in vivo using PET

  4. 11C-labelling of the analgesic Tramadol and its major metabolites by selective O- and N-methylation

    For in vivo pharmacokinetic studies with PET, the analgesic Tramadol(1-(3-methoxyphenyl)-2-dimethylaminomethyl-cyclohexan-1-ol) and its major O- and N-desmethylated metabolites M1 and M2 were labelled with carbon-11. Starting with the corresponding desmethyl precursors, [O-methyl-11C]Tramadol and racemic[N-methyl-11C]Tramadol were prepared by methylation with n.c.a. [11C]methyl iodide in DMSO with radiochemical yields of 85 and 90%, respectively. Specific n.c.a. N-methylation of bis-desmethyl-Tramadol (M5) was achieved with 90% radiochemical yield. However, a selective O-methylation of M5 was not possible even with an excess of NaOH, and only 70% of [O-methyl-11C]M2 was obtained. Quaternization of Tramadol or M1 was >15 times slower than O-methylation, and was only observed in the presence of added CH3I carrier. (author)

  5. Synthesis of a 11C-labeled NK1 receptor ligand for PET studies

    Changes in substance P (SP) receptor concentration have been implicated in neuropsychiatric disorders, Parkinson's disease, arthritis, inflammatory bowel disease and asthma. Since, SP and peptide analogs are rapidly metabolized and do not penetrate into the CNS, they are not useful for PET. Recently, a non-peptide SP antagonist, (+)-(2S,3S)-3-(2-methoxybenzylamino)-2-phenylpiperidine (CP-99,994) was developed. As a prelude to PET studies, this compound was radiolabeled with 11C and biodistribution was determined in hamsters. CP-99,994 was radiolabeled by methylation of tert-Boc, desmethyl CP-99,994 with 11CH3I followed by deprotection and HPLC purification. The time required for the synthesis was 40 min from the end of bombardment. Radiochemical purity of the final product was > 95% and specific activity was routinely > 1000 mCi/μmol [EOS]. The biodistribution of 11C-CP-99,994 was determined in groups of six Syrian hamsters at 5 and 30 min after injection. The results of these studies demonstrated that significant concentrations (%ID/g ± SEM) of CP-99,994 accumulate in most tissues of the hamster. The highest levels of drug were detected in the lung: 21.04 ± 1.26 (5 min) and 13.49 ± 1.71 (30 min). Brain accumulation was: 1.44 ± 0.06 (5 min), 1.32 ± 0.05 (30 min). These results indicate that 11C-CP-99,994 can be prepared in high purity and specific activity. This new radiopharmaceutical may be useful for studying both central and peripheral SP receptors by PET

  6. Preparation and pharmacokinetics of 11C labeled stavudine (d4T)

    Stavudine, a potent antiviral agent for treating human immunodeficiency virus (HIV) infections, was radiolabeled with 11C by methylation of a specifically designed precursor, 5'-O-(2-tetrahydropyranyl)-5-bromo-2',3'-didehydro-3'-deoxythymidine, with 11C H3I. The radiolabeled drug was isolated by reverse phase HPLC. A total time of approximately 45 minutes was required for synthesis, purification and isolation of 11C stavudine with chemical and radiochemical purities of greater than 98%. 11C stavudine was combined with unlabeled drug (2.0 mg/kg) and used to study its pharmacokinetics in rats by measurement of radioactivity in excised tissues. In this species, there was rapid accumulation of drug in all tissue. In all tissues, with the exceptions of testis and brain, highest concentrations of drug were detected at 5 minutes after injection and decreased monotonically thereafter. The peak concentration (μg/g) of stavudine in blood was 1.78 ± 0.16 and similar levels were achieved in most other tissues; heart 1.66 ± 0.11, lung 1.60 ± 0.15, liver 2.13 ± 0.17, spleen 1.61 ± 0.15, adrenal 1.47 ± 0.20, stomach 1.40 ± 0.11, GI tract 1.44 ± 0.14, skeletal muscle 1.38 ± 0.15 and bone 1.30 ± 0.16. Much higher peak concentrations were achieved in kidney; 7.23 ± 0.57 μg/g. Concentrations in testis were lower and remained relatively constant over 1 hour; peak 0.62 ± 0.14 μg/g at 15 min Brain concentrations were low but increased monotonically over time; peak 0.26 ± 0.02 μg/g at 60 min. Future PET studies with this radiopharmaceutical will allow in vivo measurements of the pharmacokinetics of stavudine in both animal models and human subjects

  7. Labeling of complex molecules with 18F, 13N, and 11C. Progress report, March 1, 1981-February 28, 1982

    The overall objective during the period covered by this report was to develop a broad spectrum of radiopharmaceuticals labeled with short-lived cyclotron produced positron emitters, 11C, 13N and 18F. The progress report of this year will summarize work done in the last three years. The goals of the program during the last three years were: to build and complete the transport system to Nuclear Medicine; to complete the modular automated system for important precursor production: formaldehyde, methyliodide, cyanide; to perform animal studies with the 18F-glucose analogs 2FDG and 3FDG and measure the rate constants and glucose metabolic rates derived from the Sokoloff model for both agents in different animal species; to initiate the development of new fatty acid analogs for myocardial imaging and metabolism; and to develop syntheses for 18F and 11C sugar analogs

  8. Application of Microreactor to the Preparation of C-11-Labeled Compounds via O-[11C]Methylation with [11C]CH3I: Rapid Synthesis of [11C]Raclopride.

    Kawashima, Hidekazu; Kimura, Hiroyuki; Nakaya, Yuta; Tomatsu, Kenji; Arimitsu, Kenji; Nakanishi, Hiroaki; Ozeki, Eiichi; Kuge, Yuji; Saji, Hideo

    2015-01-01

    A new radiolabeling method using a microreactor was developed for the rapid synthesis of [(11)C]raclopride. A chip bearing a Y-shaped mixing junction with a 200 µm (width)×20 µm (depth)×250 mm (length) flow channel was designed, and the efficiency of O-[11C]methylation was evaluated. Dimethyl sulfoxide solutions containing the O-desmethyl precursor or [11C]CH3I were introduced into separate injection ports by infusion syringes, and the radiochemical yields were measured under various conditio...

  9. Synthesis of some 11C-labelled MAO-A inhibitors and their in vivo uptake kinetics in rhesus monkey brain

    Five potential MAO-A inhibitors--harmine, N-methyl-harmine, harmaline, brofaromine, and clorgyline--were labelled with 11C and their brain kinetics evaluated in vivo in rhesus monkey using PET. The compounds were synthesized by alkylation with 11C methyl iodide and obtained in 48-89% radiochemical yield within 40 to 45 min synthesis time and with specific radioactivities in the region of 0.49-2.4 Ci μmol-1 (18-87 GBq μmol-1) at the end of synthesis. The kinetic pattern after administration of MAO-A inhibitors was comparable to that seen in the tracer study when using 11C-brofaromine, 11C-harmaline, or 11C-clorgyline, although the magnitude of uptake markedly increased in the case of brofaromine and harmaline. Both 11C-methylharmine and 11C-harmine showed a significant washout in the inhibition studies. The kinetics of brain uptake with and without MAO-A inhibition is compatible with a significant fraction of the tracer bound to MAO-A for 11C-methylharmine and 11C-harmine, whereas 11C-brofaromine, 11C-harmaline, or 11C-clorgyline did not seem to show specific enzyme binding

  10. Labelling of the solvent DMSO as side reaction of methylations with n.c.a. [11C]CH3I

    Competing labelling of solvent dimethyl sulfoxide (DMSO) can occur during the 11C-methylation of amine precursors. A kinetic analysis of the methylation reaction of DMSO with n.c.a. [11C]CH3I was performed at 120 deg. C resulting in rate constants. The rate constant for the formation of the intermediate, methylated DMSO ([11C]DMSO-M), is compared to the reaction of [11C]CH3I with two tertiary amines, namely Dexetimide and Desmethyloxotremorine-M. The specific activity of the labelled product is reduced due to partial 12C-methylation of the precursor amines by [11C]DMSO-M in cases of significant DMSO labelling as side reaction

  11. 11C-labelling of ohmefentanyl: An agonist for μ-opiate receptor

    Ohmefentanyl: cis-N-[1-(beta-hydroxy-beta-phenylethyl)-3-methyl-4-piperydyl]-N-phenylpropionamide, is a synthetic narcotic analgesic agent with an analgesic activity 28 times more potent than that of fentanyl and 6,300 times more than that of morphine. The authors have developed a method for labelling of this compound with carbon-11 for the purpose of visualizing 'in vivo' the μ receptors by PET

  12. Cyclotron production of molecules labelled with short-lived radioisotopes β+ emitters (15O, 13N, 11C) and their clinical uses

    Clinical use of three short-lived radioisotopes: 15O, 13N and 11C is studied on two complementary aspects. A production and purification system is realized; detection instruments in medical use are studied. The production of labelled molecules with the three radiotracers 15O, 13N, 11C from the target bombardment with charged and accelerated particles was studied

  13. Transport mechanism of 11C-labeled L- and D-methionine in human-derived tumor cells

    Introduction: S-methyl-11C-labeled L- and D-methionine (11C-L- and D-MET) are useful as radiotracers for tumor imaging. However, it is not known whether the transport mechanism of 11C-D-MET is the same as that for 11C-L-MET, which is transported by the amino acid transport system L. In this study, we investigated the transport mechanism of 11C-L- and D-MET by analyzing the expression of transport system genes in human-derived tumor cells. Methods: The expression of transport system genes in human-derived tumor cells was quantitatively analyzed. The mechanism of MET transport in these cells was investigated by incubating the cells with [S-methyl-3H]-L-MET (3H-L-MET) or [S-methyl-3H]-D-MET (3H-D-MET) and the effect of 2-amino-2- norbornane-carboxylic acid, a system L transport inhibitor, or α-(methylamino)isobutyric acid, a system A transport inhibitor, on their transport was measured. The transport and metabolic stability of [S-methyl-14C]-L-MET (14C-L-MET) and 3H-D-MET was also analyzed using bearing mice with H441 or PC14 tumor cells. Results: 3H-D-MET was mainly transported by both systems L and alanine–serine–cysteine (ASC), while system L was involved in 3H-L-MET transport. There was a high correlation between both 3H-L-MET and 3H-D-MET uptake and the expression of amino acid transport system genes. In the in vivo study, H441-cell accumulation of 3H-D-MET was higher than that of 14C-L-MET. Hepatic and renal accumulation of 3H-D-MET was lower than that of 14C-L-MET. Conclusion: The transport mechanism of 3H-D-MET was different from that of 3H-L-MET. Since 3H-D-MET has high metabolic stability, its accumulation reflects the transporter function of system L and ASC.

  14. Evaluation of the brain uptake properties of [1-11C] labeled hexanoate in anesthetized cats by means of positron emission tomography

    Positron emission tomography (PET) was performed on the cat brain to characterize [1-11C] hexanoate and other [1-11C] labeled short and medium-chain fatty acids as a tracer of fatty acid oxidative metabolism. After an intravenous injection the brain uptake of [1-11C] hexanoate reached a peak followed by rapid washout until 2 min (first phase). Subsequently the total brain uptake was again increased and reached to a peak 7-10 min after tracer injection (second phase). The blood radioactivity of unmetabolized [1-11C] hexanoate was rapidly decreased and almost eliminated within the first 2 min, whereas the blood radioactivity of [11C]CO2/HCO3- was gradually increased and reached a peak approximately 5 min after tracer injection. As the effect of circulating [11C]CO2/HCO3- was examined by a bolus intravenous injection of [11C]CO2/HCO3-, the brain uptake of [11C]CO2/HCO3- was rapidly increased right after the injection and changed parallel to the blood level of [11C]CO2/HCO3-. These results suggest that, in contrast to the previous mouse data, the time-activity curve in the cat brain following intravenous injection of [1-11C] hexanoate has a biphasic pattern, the second phase being determined by peripherally originating [11C]CO2/HCO3-, and therefore does not reflect the metabolism of 11C-labeled fatty acid in the brain. (author)

  15. No-carrier-added carbon-11-labeled sn-1,2- and sn-1,3-diacylglycerols by [11C]propyl ketene method

    This article describes the preparation of sn-1,2-[11C]diacylglycerols and sn-1,3-[11C]diacylglycerols by a no-carrier-added reaction based on a labeling method using [1-11C]propyl ketene, which is one of the most potent acylating agents. [1-11C]Propyl ketene was produced by pyrolytic decomposition of [1-11C]butyric acid and was trapped in pyridine containing L-alpha-palmitoyl-lysophosphatidylcholine, producing L-alpha-palmitoyl-2-[1-11C]butyryl-sn-glycero-3-phosphorylcholine. The authors adopted an enzymatic reaction to remove the phosphorylcholine, in which L-alpha-palmitoyl-2-[1-11C]butyryl-sn-glycero-3-phosphorylcholine was incubated with phospholipase C, hydrolyzing to produce 1-palmitoyl-sn-2-[1-11C]butyrylglycerol. Total synthesis time was about 50 minutes and the specific activity was estimated at 93 GBq/mumol (2.5 Ci/mumol) at end of synthesis. Radiochemical yield was 3.8% based on the trapped 11CO2. sn-1,3-[11C]Diacylglycerol was also synthesized by [1-11C]propyl ketene reaction with 1-palmitoyl-sn-glycerol in a single procedure. The regional brain tissue radioactivities obtained in sn-1,2-[11C]diacylglycerol were higher than those of sn-1,3-[11C]diacylglycerol, and the regional values varied widely. In autoradiography of brain slices from conscious rats, sn-1,2-[11C]diacylglycerol incorporation sites were discretely localized, especially in the amygdala, cerebral cortex, and hippocampus, suggesting that intensive neuronal processing occurred in these areas on the basis of phosphatidylinositol turnover

  16. Radiosynthesis and in vivo evaluation of [{sup 11}C]-labelled pyrrole-2-carboxamide derivates as novel radioligands for PET imaging of monoamine oxidase A

    De Bruyne, Sylvie [Laboratory for Radiopharmacy, Ghent University, 9000 Ghent (Belgium); La Regina, Giuseppe [Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Universita di Roma, I-00185 Rome (Italy); Staelens, Steven [IBITECH-Medisip, Ghent University-IBBT, 9000 Ghent (Belgium); Wyffels, Leonie [Laboratory for Radiopharmacy, Ghent University, 9000 Ghent (Belgium); Deleye, Steven [IBITECH-Medisip, Ghent University-IBBT, 9000 Ghent (Belgium); Silvestri, Romano [Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Universita di Roma, I-00185 Rome (Italy); De Vos, Filip [Laboratory for Radiopharmacy, Ghent University, 9000 Ghent (Belgium)], E-mail: filipx.devos@ugent.be

    2010-05-15

    Introduction: Since MAO-A is an enzyme involved in the metabolism of neurotransmitters, fluctuations in MAO-A functionality are associated with psychiatric and neurological disorders as well as with tobacco addiction and behaviour. This study reports the radiolabelling of two [{sup 11}C]-labelled pyrrole-2-carboxamide derivates, RS 2315 and RS 2360, along with the characterization of their in vivo properties. Methods: The radiolabelling of [{sup 11}C]-RS 2315 and [{sup 11}C]-RS 2360 was accomplished by alkylation of their amide precursors with [{sup 11}C]CH{sub 3}I. Biodistribution, blocking and metabolite studies of both tracers were performed in NMRI mice. Finally, a PET study in Sprague-Dawley rats was performed for [{sup 11}C]-RS 2360. Results: Both tracers were obtained in a radiochemical yield of approximately 30% with radiochemical purity of >98%. Biodistribution studies showed high brain uptake followed by rapid brain clearance for both radiotracers. In the brain, [{sup 11}C]-RS 2360 was more stable than [{sup 11}C]-RS 2315. Blocking studies in mice could not demonstrate specificity of [{sup 11}C]-RS 2315 towards MAO-A or MAO-B. The blocking and imaging study with [{sup 11}C]-RS 2360 on the other hand indicated specific binding in MAO-A at the earliest time points. Conclusions: [{sup 11}C]-RS 2315 displayed a high nonspecific binding and is therefore not suitable for visualization of MAO-A in vivo. [{sup 11}C]-RS 2360 on the other hand has potential for mapping MAO-A since specific binding is demonstrated.

  17. Synthesis and preliminary evaluation of [11C]NE-100 labeled in two different positions as a PET σ receptor ligand

    N,N-Dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]ethylamine (NE-100) was labeled with 11C in two different positions by the alkylation of an N-despropyl precursor with [11C]propyl iodide and of an O-desmethyl precursor with [11C]methyl iodide and was evaluated for the potential as a tracer for mapping σ 1 receptors in the CNS and peripheral organs by PET. Following i.v. injection of [N-propyl-11C]NE-100 or [O-methyl-11C]NE-100 into mice, the two tracers showed similar tissue distribution patterns except for the liver and brain. With the coinjected carrier NE-100 or haloperidol, the uptake of [N-propyl-11C]NE-100 by the liver, pancreas and spleen was significantly decreased at 15 min after injection, whereas the effect was not significant for [O-methyl-11C]NE-100. The coinjection of NE-100 enhanced the brain uptake of the two tracers. Haloperidol also enhanced the brain uptake of [N-propyl-11C]NE-100, but not that of [O-methyl-11C]NE-100. The regional brain distribution assessed with [O-methyl-3H]NE-100 was consistent with the distribution pattern of the σ receptors. Four σ drugs reduced the regional brain uptake of [O-methyl-3H]NE-100 to 70%-90% of the control. In an ex vivo autoradiographic study of the rat brain, the uptake of [O-methyl-11C]NE-100 was blocked by carrier NE-100 or haloperidol (53%-59% of the control in the cortex), which suggests a receptor-specific distribution. These results show that [O-methyl-11C]NE-100 has limited potential as a PET ligand for mapping σ 1 receptors in the peripheral organs and the CNS because of high nonspecific binding

  18. Radiosynthesis and in vivo evaluation of [11C]-labelled pyrrole-2-carboxamide derivates as novel radioligands for PET imaging of monoamine oxidase A

    Introduction: Since MAO-A is an enzyme involved in the metabolism of neurotransmitters, fluctuations in MAO-A functionality are associated with psychiatric and neurological disorders as well as with tobacco addiction and behaviour. This study reports the radiolabelling of two [11C]-labelled pyrrole-2-carboxamide derivates, RS 2315 and RS 2360, along with the characterization of their in vivo properties. Methods: The radiolabelling of [11C]-RS 2315 and [11C]-RS 2360 was accomplished by alkylation of their amide precursors with [11C]CH3I. Biodistribution, blocking and metabolite studies of both tracers were performed in NMRI mice. Finally, a PET study in Sprague-Dawley rats was performed for [11C]-RS 2360. Results: Both tracers were obtained in a radiochemical yield of approximately 30% with radiochemical purity of >98%. Biodistribution studies showed high brain uptake followed by rapid brain clearance for both radiotracers. In the brain, [11C]-RS 2360 was more stable than [11C]-RS 2315. Blocking studies in mice could not demonstrate specificity of [11C]-RS 2315 towards MAO-A or MAO-B. The blocking and imaging study with [11C]-RS 2360 on the other hand indicated specific binding in MAO-A at the earliest time points. Conclusions: [11C]-RS 2315 displayed a high nonspecific binding and is therefore not suitable for visualization of MAO-A in vivo. [11C]-RS 2360 on the other hand has potential for mapping MAO-A since specific binding is demonstrated.

  19. Brain kinetics of 11 C-labelled L-tryptophan and 5-hydroxy-L-tryptophan in the Rhesus monkey. A study using positron emission tomography

    5-hydroxy-L-tryptophan labelled with 11 C is introduced as a tracer for the vivo assessment of brain serotonin synthesis in the Rhesus monkey using positron emission tomography, PET. Increasing radioactivities were seen in the striatal area in contrast to that seen in other brain regions. Following 11 C-labelled L-tryptophan an even spread of brain radioactivity was seen. This selective increase most probably results from the decarboxylation of tracer and retention of formed products since no striatal increase of radioactivity was seen when 5-hydroxy-L-tryptophan labelled with 11 C in the carboxy-position was administered. Furthermore, pretreatment of the monkey with a centrally active decarboxylase inhibitor (NSD 1015, 10 mg/kg) did not lead to increased striatal radioactivities after the administration of 5-hydroxy-(β-11 C)-L-tryptophan. The selective utilization of the radiotracer in the striatal area increased with a rate constant calculated to be 0.0055 ± 0.0015 min-1 (n=5) using the surrounding brain as reference area. A non-significant influence of radiolabelled metabolites to the rate constants measured was shown after pretreatment of the monkeys with selective and non-selective monoamine oxidase inhibitors, respectively. These results may give a basis for the use of the new tracer 5-hydroxy-(β-11 C)-L-tryptophan in PET-studies of brain serotonin metabolism in health and disease. (authors)

  20. Radiosynthesis of ML03, a novel positron emission tomography biomarker for targeting epidermal growth factor receptor via the labeling synthon: [11C]acryloyl chloride

    An automated procedure for the radiosynthesis of the labeling synthon [11C]acryloyl chloride was developed and applied for labeling several N-acryl amides with carbon-11. [11C]-6-acrylamido-4-(3,4-dichloro-6-fluoroanilino)quinazoline (ML03), a novel PET biomarker targeting the epidermal growth factor receptor tyrosine kinase (EGFr-TK) in cancer, was successfully prepared using this labeled synthon in a fully automated manner. Two other potential anticancer drugs were also labeled using the developed methodology. The potency of ML03 to inhibit autophosphorylation of EGFr-TK was evaluated by an ELISA assay indicating a low IC50 of 0.037 nM

  1. Rapid analysis for metabolites of 11C-labelled drugs: fate of [11C]-S-4-(tert.-butylamino-2-hydroxypropoxy)-benzimidazol-2-one in the dog.

    Jones, H A; Rhodes, C G; Law, M P; Becket, J M; Clark, J C; Boobis, A R; Taylor, G W

    1991-10-01

    Positron emission tomography (PET) requires the use of compounds labelled with short-lived, positron-emitting isotopes (e.g., t1/2 of 11C approximately 120 min). As the concentration of unbound, non-metabolised drug is required as the input function for modeling, this presents particular problems for the study of the kinetics and metabolism of such compounds. We have now developed a rapid extraction procedure, followed by high-performance liquid chromatography using a short analytical column coupled to an on-line gamma-detector to determine the metabolism and kinetics of a non-selective beta-adrenergic antagonist of high affinity, S-4-(tert.-butylamino-2-hydroxypropoxy)benzimidazol-2-one. This antagonist is potentially well suited to the non-invasive localisation of beta-receptors in vivo. The ligand was rapidly taken up into the beta-receptor pool or excreted in urine, with less than 5% of the drug converted to metabolites. Plasma protein binding was only 16%. No significant metabolism of the ligand was observed in the anaesthetised dog, and, therefore, no correction for blood metabolite concentration is required for kinetic analysis of the 11C-labelled ligand during PET studies in this species. The analytical method reported here should be widely applicable: quantification of metabolites enables accurate estimation of the input function and is critical to the interpretation of PET data. PMID:1686775

  2. Synthesis and preliminary evaluation of [{sup 11}C]NE-100 labeled in two different positions as a PET {sigma} receptor ligand

    Ishiwata, Kiichi; Noguchi, Junko; Ishii, Shin-Ichi; Hatano, Kentaro; Ito, Kengo; Nabeshima, Toshitaka; Senda, Michio

    1998-04-01

    N,N-Dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]ethylamine (NE-100) was labeled with {sup 11}C in two different positions by the alkylation of an N-despropyl precursor with [{sup 11}C]propyl iodide and of an O-desmethyl precursor with [{sup 11}C]methyl iodide and was evaluated for the potential as a tracer for mapping {sigma} 1 receptors in the CNS and peripheral organs by PET. Following i.v. injection of [N-propyl-{sup 11}C]NE-100 or [O-methyl-{sup 11}C]NE-100 into mice, the two tracers showed similar tissue distribution patterns except for the liver and brain. With the coinjected carrier NE-100 or haloperidol, the uptake of [N-propyl-{sup 11}C]NE-100 by the liver, pancreas and spleen was significantly decreased at 15 min after injection, whereas the effect was not significant for [O-methyl-{sup 11}C]NE-100. The coinjection of NE-100 enhanced the brain uptake of the two tracers. Haloperidol also enhanced the brain uptake of [N-propyl-{sup 11}C]NE-100, but not that of [O-methyl-{sup 11}C]NE-100. The regional brain distribution assessed with [O-methyl-{sup 3}H]NE-100 was consistent with the distribution pattern of the {sigma} receptors. Four {sigma} drugs reduced the regional brain uptake of [O-methyl-{sup 3}H]NE-100 to 70%-90% of the control. In an ex vivo autoradiographic study of the rat brain, the uptake of [O-methyl-{sup 11}C]NE-100 was blocked by carrier NE-100 or haloperidol (53%-59% of the control in the cortex), which suggests a receptor-specific distribution. These results show that [O-methyl-{sup 11}C]NE-100 has limited potential as a PET ligand for mapping {sigma} 1 receptors in the peripheral organs and the CNS because of high nonspecific binding.

  3. (11) C-labeled and (18) F-labeled PET ligands for subtype-specific imaging of histamine receptors in the brain.

    Funke, Uta; Vugts, Danielle J; Janssen, Bieneke; Spaans, Arnold; Kruijer, Perry S; Lammertsma, Adriaan A; Perk, Lars R; Windhorst, Albert D

    2013-01-01

    The signaling molecule histamine plays a key role in the mediation of immune reactions, in gastric secretion, and in the sensory system. In addition, it has an important function as a neurotransmitter in the central nervous system, acting in pituitary hormone secretion, wakefulness, motor and cognitive functions, as well as in itch and nociception. This has raised interest in the role of the histaminergic system for the treatment and diagnosis of various pathologies such as allergy, sleeping and eating disorders, neurodegeneration, neuroinflammation, mood disorders, and pruritus. In the past 20 years, several ligands targeting the four different histamine receptor subtypes have been explored as potential radiotracers for positron emission tomography (PET). This contribution provides an overview of the developments of subtype-selective carbon-11-labeled and fluorine-18-labeled compounds for imaging in the brain. Using specific radioligands, the H1 R expression in human brain could be examined in diseases such as schizophrenia, depression, and anorexia nervosa. In addition, the sedative effects of antihistamines could be investigated in terms of H1 R occupancy. The H3 R is of special interest because of its regulatory role in the release of various other neurotransmitters, and initial H3 R PET imaging studies in humans have been reported. The H4 R is the youngest member of the histamine receptor family and is involved in neuroinflammation and various sensory pathways. To date, two H4 R-specific (11) C-labeled ligands have been synthesized, and the imaging of the H4 R in vivo is in the early stage. PMID:24285318

  4. 11C-imaging

    Thorpe, Michael R; Ferrieri, Abigail P; Herth, Matthias Manfred;

    2007-01-01

    The long-distance transport and actions of the phytohormone methyl jasmonate (MeJA) were investigated by using the short-lived positron-emitting isotope 11C to label both MeJA and photoassimilate, and compare their transport properties in the same tobacco plants (Nicotiana tabacum L.). There was...

  5. PET imaging of fatty acid amide hydrolase in the brain: synthesis and biological evaluation of an 11C-labelled URB597 analogue

    Introduction: Fatty acid amide hydrolase (FAAH) is part of the endocannabinoid system (ECS) and has been linked to the aetiology of several neurological and neuropsychiatric disorders. So far no useful PET or SPECT tracer for in vivo visualisation of FAAH has been reported. We synthesized and evaluated a carbon-11-labeled URB597 analogue, biphenyl-3-yl [11C]-4-methoxyphenylcarbamate or [11C]-1, as potential FAAH imaging agent. Methods: The inhibitory activity of 1 was determined in vitro using recombinant FAAH. Radiosynthesis of [11C]-1 was performed by methylation using [11C]-CH3I, followed by HPLC purification. Biological evaluation was done by biodistribution studies in wild-type and FAAH knock-out mice, and by ex vivo and in vivo metabolite analysis. The influence of URB597 pretreatment on the metabolisation profile was assessed. Results: [11C]-1 was obtained in good yields and high radiochemical purity. Biodistribution studies revealed high brain uptake in wild-type and FAAH knock-out mice, but no retention of radioactivity could be demonstrated. Metabolite analysis and URB597 pretreatment confirmed the non-FAAH-mediated metabolisation of [11C]-1. The inhibition mechanism was determined to be reversible. In addition, the inhibition of URB597 appeared slowly reversible. Conclusions: Although [11C]-1 inhibits FAAH in vitro and displays high brain uptake, the inhibition mechanism seems to deviate from the proposed carbamylation mechanism. Consequently, it does not covalently bind to FAAH and will not be useful for mapping the enzyme in vivo. However, it represents a potential starting point for the development of in vivo FAAH imaging tools.

  6. Synthesis and characterization of a 11C-labelled derivative of S12968: an attempt to image in vivo brain calcium channels

    [11C]S11568 (3-ethyl 5-methyl 2-[2-(2-aminoethoxy)ethoxymethyl]-4-(2,3-dichlorophenyl)-6-methyl-1,4 -dihydropyridine-3,5-dicarboxylate) is a powerful ligand for the visualization of the cardiac calcium channel in vivo using PET. The aim of the present study was to synthesize a lipophilic, nonionized derivative of S11568 to facilitate its penetration into the brain. To increase the lipophilicity and to remove simultaneously the ionic nature of our ligand, the N-tert-butoxycarbonyl (N-Boc) derivative of S11568 was synthesized. An IC50 value of 1.7 nM for this derivative confirmed that both the affinity and selectivity for the calcium channel was unaltered by this chemical modification (S11568 with IC50 value of 9.9 nM). The biologically more active enantiomer of S11568, the levogyre isomer S12968, was labelled with 11C using [11C]iodomethane. The lipophilicity of the N-Boc derivative was increased by a factor of three to four when compared to the parent compound (as determined by the measurement of the octanol/buffer partition coefficients). In vivo, this derivative slightly crosses the blood-brain barrier, as demonstrated by a 4-fold increase (with respect to the parent compound S12968) of the radioactivity in the brain using the 11C-labelled N-Boc S12968. This uptake remained too low to be suitable for imaging calcium channels

  7. Design, Synthesis, and Evaluation of a Low-Molecular-Weight (11)C-Labeled Tetrazine for Pretargeted PET Imaging Applying Bioorthogonal in Vivo Click Chemistry.

    Denk, Christoph; Svatunek, Dennis; Mairinger, Severin; Stanek, Johann; Filip, Thomas; Matscheko, Dominik; Kuntner, Claudia; Wanek, Thomas; Mikula, Hannes

    2016-07-20

    A low-molecular-weight tetrazine labeled with the short-lived positron emitter carbon-11 was developed as a bioorthogonal PET probe for pretargeted imaging. A method for efficient and fast synthesis of this imaging agent is presented using radiolabeling of a readily available precursor. High reactivity with trans-cyclooctenes was observed and in vivo investigations including PET/MR scanning showed homogeneous biodistribution, good metabolic stability, and rapid excretion in naive mice. These properties are key to the success of bioorthogonal (11)C-PET imaging, which has been shown in a simple pretargeting experiment using TCO-modified mesoporous silica nanoparticles. Overall, this (11)C-labeled tetrazine represents a highly versatile and advantageous chemical tool for bioorthogonal PET imaging and enables pretargeting approaches using carbon-11 for the first time. PMID:27308894

  8. Evaluation of S-[[sup 11]C]citalopram as a radioligand for in vivo labelling of 5-hydroxytryptamine uptake sites

    Hume, S.P.; Lammertsma, A.A.; Bench, C.J.; Pike, V.W.; Pascali, C.; Cremer, J.E. (Hammersmith Hospital, London (United Kingdom). M.R.C. Cyclotron Unit); Dolan, R.J. (Royal Free Hospital, London (United Kingdom))

    1992-11-01

    The biologically active S-enantiomer of [N-methyl-[sup 11]C]citalopram was evaluated as a radioligand for in vivo labelling of the 5-hydroxytryptamine uptake site in brain, using ex vivo tissue counting in rats and positron emission tomography in man. In rats, the maximal signal for total versus non-specific binding was approx. 2 at 60-120 min after radioligand injection. Subsequent studies in man failed to identify a specific signal over a 90 min scanning period, due to prolonged retention of non-specific label. (author).

  9. (-)-N-[{sup 11}C]propyl-norapomorphine: a positron-labeled dopamine agonist for PET imaging of D{sub 2} receptors

    Hwang, Dah-Ren E-mail: hwang@neuron.cpmc.columbia.edu; Kegeles, Lawrence S.; Laruelle, Marc

    2000-06-01

    Imaging neuroreceptors with radiolabeled agonists might provide valuable information on the in vivo agonist affinity states of receptors of interest. We report here the radiosynthesis, biodistribution in rodents, and imaging studies in baboons of [{sup 11}C]-labeled (-)-N-propyl-norapomorphine [(-)-NPA]. (-)-[{sup 11}C]NPA was prepared by reacting norapomorphine with [{sup 11}C]propionyl chloride and a lithium aluminum hydride reduction. [{sup 11}C]Propionyl chloride was prepared by reacting [{sup 11}C]CO{sub 2} with ethylmagnesium bromide, followed by reacting with phthaloyl chloride. The radiochemical yield of (-)-[{sup 11}C]NPA was 2.5% at end of synthesis (EOS), and the synthesis time was 60 min. The specific activity was 1700{+-}1900 mCi/{mu}mol ( N=7; ranged 110-5200 mCi/{mu}mol at EOS). Rodent biodistribution studies showed high uptake of [{sup 11}C](-)-NPA in D{sub 2} receptor-rich areas, and the striatum/cerebellum ratios were 1.7, 3.4, and 4.4 at 5 min, 30 min, and 60 min postinjection, respectively. Pretreating the animals with haloperidol (1 mg/kg) decreased the striatum/cerebellum ratio at 30 min postinjection to 1.3. (-)-[{sup 11}C]NPA was also evaluated via baboon positron emission tomography (PET) studies. Under control conditions ( N=4), rapid uptake of the tracer was observed and the striatum/cerebellum ratio reached 2.86{+-}0.15 at 45 min postinjection. Following haloperidol pretreatment (0.2 mg/kg IV), the striatum/cerebellum ratio was 1.29 at 45 min postinjection. The result demonstrated the existence of specific binding of this new tracer to the D{sub 2} receptor. To our knowledge, the current finding of a striatum/cerebellum ratio of 2.8 in baboon was the highest reported with a radiolabeled D{sub 2} agonist. (-)-[{sup 11}C]NPA is a promising new D{sub 2} agonist PET tracer for probing D{sub 2} receptors in vivo using PET.

  10. Synthesis and pharmacological evaluation of 11C-labeled piperazine derivative as a PET probe for sigma-2 receptor imaging

    Introduction: Both subtypes of sigma (σ) receptors, σ1 and σ2, are over-expressed in many cancers with σ2 proposed as a biomarker of tumor proliferation. We are interested in developing a high affinity selective σ2 radioligand for in vivo monitoring of proliferative status of solid tumors and response to anti-cancer therapies. 1-Cyclohexyl-4-[3-(5-methoxy-1,2,3,4-tetrahydronaphthalen-1-yl)propyl] piperazine (PB28) represents one of the lead candidates in the development of σ receptor ligands for therapeutic and diagnostic applications. However, the utility of PB28 is limited due to its relatively high lipophilicity. Methods: A more hydrophilic analogue (–)-(S)-1 was radiolabeled with 11C via standard O-alkylation. In vitro autoradiography with [11C](–)-(S)-1 was done using rat brain slices. PET imaging was performed in mice bearing EMT6, C6 or PC-3 tumors after i.v. injection of [11C](–)-(S)-1. Results: [11C](–)-(S)-1 was produced in 53% ± 7% isolated decay-corrected yield with radiochemical and chemical purity over 99% and specific activity greater than 100 GBq/μmol. In vitro autoradiography with [11C(–)-(S)-1 resulted in a heterogeneous binding of the tracer in the rat brain with the highest radioactivity signals in the cortex region followed by cerebellum. This binding was successfully blocked by 10 μM of either haloperidol, (+)-(R)-1 or PB28. For C6 xenografts low target-to-nontarget ratio and high non-specific binding did not allow clear tumor visualization. No accumulation was visible in EMT6 tumor or in PC-3 tumor. Rat and mouse brain uptake was low and homogeneous while stronger signal was detected in the spinal cord. High accumulation of radioactivity was observed in liver and intestine suggesting hepatobiliary clearance. Conclusions: Despite excellent in vitro properties, [11C](–)-(S)-1 did not provide high enough specific binding in vivo and is, therefore, not a useful PET tracer for imaging σ2 expression in tumors

  11. The study of methanol transformation over Cu-modified ZSM-5, Beta zeolite and MCM-41 mesoporous silica using 11C-radioisotope labeling

    Complete text of publication follows. The copper-containing zeolites and mesoporous silica, among other metals, are suitable for dehydrogenation of methanol. The Cu transition metal determines the route of methanol conversion on supports of ZSM-5 and Beta zeolite as well as MCM-41 mesoporous silica. The catalysis mechanism and the catalytic property are concluded from the composition of methanol derivates over Cu-modified catalysts. The Cu ion-exchanged ZSM-5 and Beta zeolite and MCM-41 mesoporous silica were synthesized and characterized using X-ray power diffraction, scanning electron microscope, nitrogen and pyridine adsorption, X-ray fluorescency and FTIR spectroscopy. The 11C-radioactive labeling method (11C radioisotope, T1/2 = 20 min, is a gamma emitter by annihilation of its positron) is suitable for following the process of 11C-methanol con- version i.e. adsorption, desorption and catalytic transformation as well as for investigation of small amounts of molecules over catalysts by very sensitive radioactivity detectors.The 11C radioisotope was produced at cyclotron and the 11C-methanol was synthesized by a classical radiochemical method. After catalysis the 11C-radioactive and non radioactive volatile products were identified by radiogas chromatography hereby radiolabeled compound and -derivates were distinguished from other participant natural, nonradioactive carbon compounds. Along radioactive products dimethyl ether and small hydrocarbons products were formed by Bronsted acid sites of catalysts while formaldehyde and small methyl formate were formed by Cu metal over bifunctional Cu-ZSM-5, Cu-Beta zeolite and mesoporous Cu-MCM-41 silica at 240 deg C. The detection of methoxy methanol and dimethoxy methane confirmed the simultaneous presence of acid and basic sites of catalysts. At higher temperature (400 deg C) the CO and CO2 final products were dominated. In our previous works, methanol conversion to hydrocarbons was observed by dehydration over acid H

  12. Comparison of 99mTc-labeled methionine and 11C methionine radiotracer in the detection of breast carcinomas

    The cost effectiveness and non-availability of Cyclotron in underdeveloped and developing countries is a basic problem. Therefore studies were undertaken after labeling Methionine with generator produced Technetium-99m for its possible use in breast cancer imaging

  13. Synthesis of 11C labelled methyl esters: transesterification of enol esters versus BF3 catalysed esterification-a comparative study

    C-11 labelled methyl esters have been synthesized via the transesterification of enol esters in the presence of C-11 methanol and 1,3 dichlorodibutylstannoxane as catalyst. This method leaves functional groups intact and allows access to a wider variety of C-11 labelled methyl esters compared to the BF3 catalysed ester formation, which uses carboxylic acids and C-11 methanol as starting materials

  14. [11C]-Labeled Metformin Distribution in the Liver and Small Intestine Using Dynamic Positron Emission Tomography in Mice Demonstrates Tissue-Specific Transporter Dependency.

    Jensen, Jonas B; Sundelin, Elias I; Jakobsen, Steen; Gormsen, Lars C; Munk, Ole L; Frøkiær, Jørgen; Jessen, Niels

    2016-06-01

    Metformin is the most commonly prescribed oral antidiabetic drug, with well-documented beneficial preventive effects on diabetic complications. Despite being in clinical use for almost 60 years, the underlying mechanisms for metformin action remain elusive. Organic cation transporters (OCT), including multidrug and toxin extrusion proteins (MATE), are essential for transport of metformin across membranes, but tissue-specific activity of these transporters in vivo is incompletely understood. Here, we use dynamic positron emission tomography with [(11)C]-labeled metformin ([(11)C]-metformin) in mice to investigate the role of OCT and MATE in a well-established target tissue, the liver, and a putative target of metformin, the small intestine. Ablation of OCT1 and OCT2 significantly reduced the distribution of metformin in the liver and small intestine. In contrast, inhibition of MATE1 with pyrimethamine caused accumulation of metformin in the liver but did not affect distribution in the small intestine. The demonstration of OCT-mediated transport into the small intestine provides evidence of direct effects of metformin in this tissue. OCT and MATE have important but separate roles in uptake and elimination of metformin in the liver, but this is not due to changes in biliary secretion. [(11)C]-Metformin holds great potential as a tool to determine the pharmacokinetic properties of metformin in clinical studies. PMID:26993065

  15. Difficulties in dopamine transporter radioligand PET analysis: the example of LBT-999 using [18F] and [11C] labelling

    Introduction: LBT-999, (E)-N-(4-fluorobut-2-enyl)-2β-carbomethoxy-3β-(4'-tolyl)nortropane, has been developed for PET imaging of the dopamine transporter. [18F]LBT-999 PET studies in baboons showed a lower brain uptake than [11C]LBT-999 and a high bone uptake, suggesting the presence of interfering metabolites. Therefore, in vitro and in vivo metabolism of these radiotracers was investigated. Methods: Rat and human liver microsomal incubations, baboon plasma and rat brain extracts were analyzed by radio-HPLC and LC-MS-MS. Results: In vitro experiments demonstrated the formation by P450s of five polar metabolites. The main routes of LBT-999 metabolism proposed were N-dealkylation, tolyl-hydroxylation and dealkylation plus tolyl-hydroxylation. In vivo in baboons, [18F]LBT-999 was rapidly converted into a [18F]hydroxylated metabolite likely oxidized in plasma into a [18F]carboxylic acid and into unlabeled N-dealkyl-LBT-999. The latter was detected in baboon plasma and in rat brain by LC-MS-MS. The time course of unchanged [18F]LBT-999 decreased rapidly in plasma and was higher than that of [11C]LBT-999 due to the formation of unlabeled N-dealkyl-LBT-999. In rats, striatum-to-cerebellum ratios of [18F]LBT-999, [18F]hydroxylated and [18F]acidic metabolite were 20, 4.2 and 1.65, respectively, suggesting a possible accumulation of the hydroxylated compound in the striatum. Conclusion: P450s catalyzed the formation of dealkylated and hydroxylated metabolites of LBT-999. In baboons, an extensive metabolism of [18F]LBT-999, with formation of unlabeled N-dealkyl-LBT-999, [18F]fluorobutenaldehyde (or its oxidation product) and [18F]hydroxy-LBT-999 able to penetrate the brain, prevented an easy and accurate estimation of the input function of the radiotracer. CYP3A4 being the main P450 involved in the metabolism of LBT-999, a similar pathway may occur in humans and confound PET quantification.

  16. Preliminary evaluation of 11C labelled 4-(n-2,4-dihydroxybenzyl) amino methyl benzoate a reversible tyrosine kinase inhibitor as a radiopharmaceutical

    Full text: Chronic myeloid leukaemia (CML) is a malignant blood disorder affecting primitive stem cells. The incidence is 1 - 1.5/100,000 in Australia, with 400 new cases presenting each year, Recent reports have shown the incidence of CML to be on the increase. Current diagnosis during the early stage of CML is inadequate; anecdotal evidence suggests early disease detection can improve outcome. The expression of tyrosine kinase p210 (BCR/ABL) as the result of gene translocation is the hallmark of CML. This has lead to a class of compounds called tyrosine kinase inhibitors being investigated both as a diagnostic and therapeutic agents. AG957 is a reversible selective inhibitor of p210 (BCR/ABL) tyrosine phosphorylation; however, it is very susceptible to oxidation in solution. An analogue, 4-(N-2,4-dihydroxybenzyl) amino methyl benzoate was synthesised for the following reasons: we hypothesised by relocating the hydroxyl group from the 5 to the 4 position on the benzene ring, it would be less susceptible to oxidation and still retain its selectivity for p210(BCR/ABL). A three step radiolabelling method of AG957 with 11C was reported by Ackermann et al. The same radiolabelling technique was used for the synthesis of this analogue. This paper reports the suitability of 11C labelled 4-(N-2,4-dihydroxybenzyl) amino methyl benzoate as a pharmaceutical injectable. With our preliminary data on the chemical purity, radiochemical purity and its stability in solution, this compound is suitable for further cell binding and animal studies. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc

  17. Synthesis and biodistribution of a new radiotracer for in vivo labeling of serotonin uptake sites by PET, cis-N,N-[[sup 11]C]dimethyl-3-(2',4'-dichlorophenyl)-indanamine (cis-[[sup 11]C]DDPI)

    Suehiro, Makiko; Scheffel, U.; Dannals, R.F.; Wilson, A.A.; Ravert, H.T.; Wagner, H.N. Jr. (Johns Hopkins Medical Institutions, Baltimore, MD (United States))

    1992-07-01

    A new PET radiotracer for in vivo labeling of serotonin (5-HT) uptake sites, cis-N,N-[[sup 11]C]dimethyl-3-(2',4'-dichlorophenyl)-indanamine, cis-[[sup 11]C]DDPI, was synthesized and its biological behavior was studied. The radiosynthesis of cis-[[sup 11]C]DDPI was performed by N-methylation of cis-N-methyl-3-(2',4'-dichlorophenyl)-indanamine with [[sup 11]C]iodomethane. The average radiochemical yield was approx. 8%, with an average specific activity of 600 mCi/[mu]mol. Following intravenous administration, cis-[[sup 11]C]DDPI accumulated in mouse brain regions rich in 5-HT uptake sites, such as olfactory tubercles, hypothalamus and frontal cortex. Following pre-injection of 1 mg/kg of paroxetine, a high affinity 5-HT uptake blocker, the binding of cis-[[sup 11]C]DDPI in the olfactory tubercles, hypothalamus and frontal cortex was decreased by 23, 25 and 16%; this corresponds to 73, 82 and 59% of the specific binding in these regions. These results suggest that the accumulation of cis-[[sup 11]C]DDPI in the tissues rich in 5-HT sites is a result of specific binding of cis-[[sup 11]C]DDPI to 5-HT uptake sites. Due to the relatively high non-specific uptake and slow clearance of this compound from non-specific binding sites, the ratio between specific and non-specific binding increased slowly with time, reaching 1.5:1 at 60 min after injection. (Author).

  18. Evaluation of the P-glycoprotein- and breast cancer resistance protein-mediated brain penetration of 11C-labeled topotecan using small-animal positron emission tomography

    Introduction: Topotecan (TPT) is a camptothecin derivative and is an anticancer drug working as a topoisomerase-I-specific inhibitor. But TPT cannot penetrate through the blood-brain barrier. In this study, we synthesized a new positron emission tomography (PET) probe, [11C]TPT, to evaluate the P-glycoprotein (Pgp)- and breast cancer resistance protein (BCRP)-mediated brain penetration of [11C]TPT using small-animal PET. Methods: [11C]TPT was synthesized by the reaction of a desmethyl precursor with [11C]CH3I. In vitro study using [11C]TPT was carried out in MES-SA and doxorubicin-resistant MES-SA/Dx5 cells in the presence or absence of elacridar, a specific inhibitor for Pgp and BCRP. The biodistribution of [11C]TPT was determined using small-animal PET and the dissection method in mice. Results: The transport of [11C]TPT to the extracellular side was determined in MES-SA/Dx5 cells exhibiting the expressions of Pgp and BCRP at high levels. This transport was inhibited by coincubation with elacridar. In Mdr1a/b-/-Bcrp1-/- mice, PET results indicated that the brain uptake of [11C]TPT was about two times higher than that in wild-type mice. Similarly, the brain penetration of [11C]TPT in wild-type mice was increased by treatment with elacridar. The radioactivity in the brain of elacridar-treated mice was maintained at a certain level after the injection of [11C]TPT, although the radioactivity in the blood decreased with time. Conclusions: We demonstrated the increase of brain penetration of [11C]TPT by deficiency and inhibition of Pgp and BCRP functions using small-animal PET in mice.

  19. Synthesis of {sup 11}C-labeled desipramine and its metabolite 2-hydroxydesipramine: Potential radiotracers for PET studies of the norepinephrine transporter

    Dort, Marcian E. van; Kim, Jae-Hoon; Tluczek, Louis; Wieland, Donald M

    1997-11-01

    The antidepressant desipramine (DMI) and its principal metabolite 2-hydroxydesipramine (HDMI) have been radiolabeled with {sup 11}C for PET studies. The normethyl precursors of DMI and HDMI were synthesized from iminodibenzyl in 35% and 11% overall yield, respectively. Direct methylation of the normethyl precursor with [{sup 11}C]CH{sub 3}I, followed by HPLC purification, provided [{sup 11}C]DMI and [{sup 11}]HDMI in 18-30% and 15-23% decay-corrected radiochemical yields, respectively, in a 45 min synthesis time from end of bombardment. The specific activities of the two radiotracers were >1459 Ci/mmol at the end of synthesis. [{sup 11}C]DMI and [{sup 11}C]HDMI have potential utility as PET radiotracers for the norepinephrine transporter.

  20. Study of the production yields of 18F, 11C, 13N and 15O positron emitters from plasma-laser proton sources at ELI-Beamlines for labeling of PET radiopharmaceuticals

    Amato, Ernesto; Italiano, Antonio; Margarone, Daniele; Pagano, Benedetta; Baldari, Sergio; Korn, Georg

    2016-03-01

    The development of novel compact PET radionuclide production systems is of great interest to promote the diffusion of PET diagnostics, especially in view of the continuous development of microfluidics labeling approaches. We studied the feasibility to produce clinically-relevant amounts of PET isotopes by means of laser-accelerated proton sources such that expected at the ELI-Beamlines facility. 18F, 11C, 13N and 15O production yields were calculated through the TALYS software, by taking into account the broad proton spectra expected. With the hypothesized proton fluencies, clinically-relevant amounts of radionuclides can be obtained, suitable to prepare single doses of 18F-, 11C- and 13N-labeled radiopharmaceuticals exploiting fast and efficient microfluidic labeling systems.

  1. In vivo evaluation of [11C]- and [18F]-labelled cocaine analogues as potential dopamine transporter ligands for positron emission tomography

    Four analogues of the potent dopamine transporter ligand, WIN 35,428, were radiolabelled with 11C and 18F at the 2-β-carboxy position for evaluation as potential ligands for imaging dopamine uptake sites by positron emission tomography (PET) namely, methyl (1R-2-exo-3-exo)-8-methyl-3-(4-methylphenyl)-8-azabicyclo[3.2.1]octane-2- carboxylate (RTI-32), its 4-chlorophenyl analogue (RTI-31), 2'-fluoroethyl (1R-2-exo-3-exo)-8-methyl-3-(4-methylphenyl)-8-azabicyclo[3.2.1]octane-2- carboxylate (FETT) and its 4-chlorophenyl analogue (FECT). Upon intravenous injection in rats, all four radiotracers displayed preferential accumulation of radioactivity in regions known to contain high concentrations of dopamine uptake sites. Competition studies with two of the analogues, [11C]RTI-32 and [18F]FETT, demonstrated that, for both radiotracers, binding was saturable and displayed the appropriate pharmacology as potential PET ligands for imaging the dopamine transporter. Striatum to cerebellar ratios for [11C]RTI-32 (at 90 min post-injection) and [18F]FETT (at 120 min post-injection) were 27 and 21, respectively

  2. A simple, versatile, low-cost and remotely operated apparatus for [11C]acetate, [11C]choline, [11C]methionine and [11C]PIB synthesis

    A simple, efficient and remotely operated synthesis apparatus for carrying out routine [11C]carboxylation, on-column and bubbling [11C]methylation was essential for reliable, day-to-day production of [11C]-labelled PET radiopharmaceuticals. We developed an in-house apparatus specifically applied to the synthesis of [11C]acetate, [11C]choline, [11C]methionine and 2-(4'-N-[11C]methylaminophenyl)-6-hydroxybenzothiazole ([11C]PIB), where high radiochemical purity (≥97%) and moderate radiochemical yields (18% for [11C]PIB, 41-55% for the others) could be achieved. These findings provided evidence that this was a fast, versatile and reliable apparatus suitable for a PET/CT centre with limited financial budget and hot cell space for synthesis of [11C]-labelled radiopharmaceuticals

  3. 1-/sup 11/C-D-glucose and related compounds

    Shiue, C.Y.; Wolf, A.P.

    1982-01-26

    The novel compounds 1-/sup 11/C-D-glucose, 1-/sup 11/C-D-mannose, 1-/sup 11/C-D-galactose, 2-/sup 11/C-D-glucose, 2-/sup 11/C-D-mannose and 2-/sup 11/C-D-galactose which can be used in nuclear medicine to monitor the metabolism of glucose and galactose can be rapidly prepared by reaction of the appropriate aldose substrate with an alkali metal /sup 11/C-labeled cyanide followed by reduction with a Raney alloy in formic acid.

  4. Enhanced radiosyntheses of [11C]raclopride and [11C]DASB using ethanolic loop chemistry

    Introduction: To improve the synthesis and quality control of carbon-11 labeled radiopharmaceuticals, we report the fully automated loop syntheses of [11C]raclopride and [11C]DASB using ethanol as the only organic solvent for synthesis module cleaning, carbon-11 methylation, HPLC purification, and reformulation. Methods: Ethanolic loop chemistry is fully automated using a GE TRACERLab FXC-Pro synthesis module, and is readily adaptable to any other carbon-11 synthesis apparatus. Precursors (1 mg) were dissolved in ethanol (100 μL) and loaded into the HPLC loop. [11C]MeOTf was passed through the HPLC loop and then the labeled products were purified by semi-preparative HPLC and reformulated into ethanolic saline. Results: Both [11C]raclopride (3.7% RCY; > 95% RCP; SA = 20831 Ci/mmol; n = 64) and [11C]DASB, both with (3.0% RCY; > 95% RCP; SA = 15152 Ci/mmol; n = 9) and without (3.0% RCY; > 95% RCP; SA = 10931 Ci/mmol; n = 3) sodium ascorbate, have been successfully prepared using the described methodology. Doses are suitable for human use and the described methods are now employed for routine clinical production of both radiopharmaceuticals at University of Michigan. Conclusions: Ethanolic loop chemistry is a powerful technique for preparing [11C]raclopride and [11C]DASB, and we are in the process of adapting it for other carbon-11 radiopharmaceuticals prepared in our laboratories ([11C]PMP, [11C]PBR28 etc.).

  5. Feasibility of labeled α-acetamido-aminoisobutyric acid as new tracer compound for kinetic labeling of neutral amino acid transport: Preparation of α-(N-[1-11C]acetyl)- and α-(N-[1-14C]acetyl)-aminoisobutyric acid

    The nonphysiological, nonracemic, branched-chain α-acetamido-aminoisobutyric acid was labeled with the carbon isotope 11C with the intention to use it in conjunction with positron emission tomography (PET) to measure the kinetics of amino acid transport in vivo. It was produced by the reaction of the novel 11C-precursor N-[1-11C]acetylpyridinium chloride with α-aminoisobutyric acid. Typically, 2 GBq of α-(N-[1-11C]acetyl)-aminoisobutyric acid were isolated with a specific activity of 12 to 20 GBq · μmol-1 at the time of application, and with a radiochemical purity of >98%. The chemical identity of α-(N-[1-11C]acetyl)-aminoisobutyric acid was confirmed by comparison with α-(N-[1-14C]acetyl)-aminoisobutyric acid that was independently prepared by a standard acetylation procedure of α-aminoisobutyric acid using [1-14C]acetic anhydride. In vivo, both labeled substrates were not metabolized. In cell-culture experiments, 84% of the substrate entered the cells by the sodium-dependent amino acid transport system A, whereas 16% was taken up by the sodium-independent system. The uptake of the radiotracer was measured 20 min and 40 min postinjection in tumor-bearing male Copenhagen rats for assessment of its in vivo biodistribution

  6. Analysis of plasma metabolites during human PET studies with three receptor ligands, [11C]YM-09151-2, [11C]doxepin and [11C]pyrilamine

    Carbon-11 labeled metabolites in human plasma were analyzed by high-performance liquid chromatography during positron emission tomography (PET) studies using the dopamine D2 ligand [11C]YM-09151-2 as well as the histamine H1 ligands [11C]doxepin and [11C]pyrilamine. For all the three tracers, blood clearance of the radioactivity was extremely rapid after an i.v. injection. The plasma protein-binding of [11C]YM-09151-2 and [11C]doxepin had protective effects upon the metabolic alteration of the ligands, whereas [11C]pyrilamine was free from the protein-binding and immediately degraded. The degradation of [11C]doxepin was more rapid in epileptic patients on medication than in normal subjects. These results indicate that analysis of metabolites in the plasma is necessary to determine the accurate arterial input function for quantitative PET measurement. (author)

  7. Use of a column-switching high-performance liquid chromatography method to assess the presence of specific binding of (R)- and (S)-[11C]rolipram and their labeled metabolites to the phosphodiesterase-4 enzyme in rat plasma and tissues

    Introduction: To complement recent studies using the high-affinity 11C-labeled phosphodiesterase-4 (PDE4) inhibitor (R)-rolipram and the less active enantiomer (S)-[11C]rolipram for in vivo quantification of PDE4 levels, we evaluated the presence of radiolabeled metabolites and their potential binding to PDE4 in the rat plasma, brain, heart, pancreas, skeletal muscle and brown adipose tissue. Methods: A reverse-phase capture and analytical HPLC column-switch method was used to detect (R)-[11C]rolipram, (S)-[11C]rolipram and their radiolabeled metabolites in rat plasma and tissue extracts. The relative proportion of PDE4-specific binding of the radiotracers and their labeled metabolites was analyzed following co-injections with a saturating dose of unlabeled (R)-rolipram at 45 min post-tracer injection in tissue extracts. Results: Radiolabeled metabolites were found in the plasma (72-75% of total radioactive signal), and in the heart, skeletal muscle, pancreas and brown adipose tissue (44-52%), but not in the brain. In comparison to polar labeled metabolites, the proportion of unchanged (R)-[11C]rolipram was reduced in PDE4-rich organs by co-injection of unlabeled (R)-rolipram. Conversely, no changes were obtained in brown adipose tissue, or with (S)-[11C]rolipram, suggesting that radiolabeled metabolites of (R)-[11C]rolipram display no specific binding to PDE4. Conclusions: Radiolabeled hydrophilic metabolites are unlikely to compete with (R)-[11C]rolipram for PDE4-specific retention. However, due to the high proportion of the radioactive metabolites in the total radioactive signal, any kinetic modeling calculations in the peripheral tissues will need to take into account the presence of labeled metabolites

  8. Automated photosynthesis of 11C-glucose

    Glucose and fructose, labelled with 11C, were produced by passing 11CO2 into an evacuated chamber containing spinach leaves. Photosynthesis was carried out by day light lamp illumination. 75-95% of the 11CO2 was absorbed by the leaves and the radioactivity in the leaves was extracted in ethanol as sugars. Radiochemical purity was determined by HPLC. The automated system was controlled by timers. (U.K.)

  9. Preparation of [1-11C]dopamine, [1-11C]p-tyramine and [1-11C]m-tyramine. Autoradiography and PET examination of [1-11C]dopamine in primates

    A method for no-carrier-added 1-11C-labelling of 3-hydroxy-, 4-hydroxy- and 3,4-dihydroxy-substituted phenethylamines is described. [11C]Dopamine, [11C]p-tyramine and [11C]m-tyramine were prepared from on-line produced [11C]nitromethane. Condensation of [11C] nitromethane with various protected and unprotected benzaldehydes was investigated. A one-pot two-step reduction of the substituted 11C-labelled nitrostyrene intermediates gave after hydrolysis and purification the corresponding labelled amines in a total radiochemical yield of 8-20% and a specific radioactivity of 400-1000 Ci/mmol. The radiochemical purity was higher than 98%. [11C]Dopamine was used for in vitro autoradiography on human post-mortem brain sections and for positron emissions tomography (PET) on Cynomolgus monkeys. Autoradiographic examinations of [11C]dopamine binding on human brain section post-mortem demonstrated specific binding in the caudate putamen and the substantia nigra, regions with a dense dopaminergic innervation. Some binding was also seen in the globus pallidum, nucleus ventralis of the thalamus and in nucleus dentatus of the cerebellum, regions where the dopaminergic innervation is very low. In PET examinations of [11C]dopamine binding in Cynomolgus monkeys there was a high uptake of radioactivity in the pituitary, the kidneys and the heart. Any passage of [11C]dopamine across the blood-brain barrier could not be demonstrated. In human PET studies [11C]dopamine has potential as a radioligand for examination of the myocardium, pituitary and kidneys. (Author)

  10. Evaluation of the P-glycoprotein- and breast cancer resistance protein-mediated brain penetration of {sup 11}C-labeled topotecan using small-animal positron emission tomography

    Yamasaki, Tomoteru; Fujinaga, Masayuki; Kawamura, Kazunori; Hatori, Akiko; Yui, Joji [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Nengaki, Nobuki; Ogawa, Masanao; Yoshida, Yuichiro [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); SHI Accelerator Service, Ltd., Tokyo 141-8686 (Japan); Wakizaka, Hidekatsu [Department of Biophysics, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Yanamoto, Kazuhiko [Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka 565-0871 (Japan); Fukumura, Toshimitsu [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Zhang Mingrong, E-mail: zhang@nirs.go.jp [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan)

    2011-07-15

    Introduction: Topotecan (TPT) is a camptothecin derivative and is an anticancer drug working as a topoisomerase-I-specific inhibitor. But TPT cannot penetrate through the blood-brain barrier. In this study, we synthesized a new positron emission tomography (PET) probe, [{sup 11}C]TPT, to evaluate the P-glycoprotein (Pgp)- and breast cancer resistance protein (BCRP)-mediated brain penetration of [{sup 11}C]TPT using small-animal PET. Methods: [{sup 11}C]TPT was synthesized by the reaction of a desmethyl precursor with [{sup 11}C]CH{sub 3}I. In vitro study using [{sup 11}C]TPT was carried out in MES-SA and doxorubicin-resistant MES-SA/Dx5 cells in the presence or absence of elacridar, a specific inhibitor for Pgp and BCRP. The biodistribution of [{sup 11}C]TPT was determined using small-animal PET and the dissection method in mice. Results: The transport of [{sup 11}C]TPT to the extracellular side was determined in MES-SA/Dx5 cells exhibiting the expressions of Pgp and BCRP at high levels. This transport was inhibited by coincubation with elacridar. In Mdr1a/b{sup -/-}Bcrp1{sup -/-} mice, PET results indicated that the brain uptake of [{sup 11}C]TPT was about two times higher than that in wild-type mice. Similarly, the brain penetration of [{sup 11}C]TPT in wild-type mice was increased by treatment with elacridar. The radioactivity in the brain of elacridar-treated mice was maintained at a certain level after the injection of [{sup 11}C]TPT, although the radioactivity in the blood decreased with time. Conclusions: We demonstrated the increase of brain penetration of [{sup 11}C]TPT by deficiency and inhibition of Pgp and BCRP functions using small-animal PET in mice.

  11. On-line ( sup 11 C)methylation using ( sup 11 C)methyl iodide for the automated preparation of sup 11 C-radiopharmaceuticals

    Iwata, Ren; Pascali, C.; Yuasa, Mitsuaki; Takahashi, Toshihiro; Ido, Tatsuo (Tohoku Univ., Sendai (Japan). CYRIC); Yanai, Kazuhiko (Tohoku Univ., Sendai (Japan). School of Medicine)

    1992-09-01

    A novel method for the efficient preparation of {sup 11}C-radiopharmaceuticals by on-line ({sup 11}C)methylation using ({sup 11}C)methyl iodide has been developed and applied to a rapid, convenient automated system. ({sup 11}C)Methyl iodide is first trapped in a short column, containing an adsorber and coated substrate, which is connected to an HPLC injector. DMF is then introduced. Alternatively the substrate is added with the DMF. A whole reaction mixture can be easily injected onto a HPLC column for purification by switching the injector valve immediately after the reaction. Thus, radiochemical yields in the preparation of {sup 11}C-labelled doxepin, benztropine, cyproheptadine and N-methylspiperone have been improved remarkably and the synthetic procedure simplified. (author).

  12. On-line [11C]methylation using [11C]methyl iodide for the automated preparation of 11C-radiopharmaceuticals

    A novel method for the efficient preparation of 11C-radiopharmaceuticals by on-line [11C]methylation using [11C]methyl iodide has been developed and applied to a rapid, convenient automated system. [11C]Methyl iodide is first trapped in a short column, containing an adsorber and coated substrate, which is connected to an HPLC injector. DMF is then introduced. Alternatively the substrate is added with the DMF. A whole reaction mixture can be easily injected onto a HPLC column for purification by switching the injector valve immediately after the reaction. Thus, radiochemical yields in the preparation of 11C-labelled doxepin, benztropine, cyproheptadine and N-methylspiperone have been improved remarkably and the synthetic procedure simplified. (author)

  13. In vivo positron emission tomography studies on the novel nicotinic receptor agonist [11C]MPA compared with [11C]ABT-418 and (S)(-)[11C]nicotine in Rhesus monkeys

    The novel 11C-labeled nicotinic agonist (R,S)-1-[11C]methyl-2(3-pyridyl)azetidine ([11C]MPA) was evaluated as a positron emission tomography (PET) ligand for in vivo characterization of nicotinic acetylcholine receptors in the brain of Rhesus monkeys in comparison with the nicotinic ligands (S)-3-methyl-5-(1-[11C]methyl-2-pyrrolidinyl)isoxazol ([11C]ABT-418) and (S)(-)[11C]nicotine. The nicotinic receptor agonist [11C]MPA demonstrated rapid uptake into the brain to a similar extent as (S)(-) [11C]nicotine and [11C]ABT-418. When unlabeled (S)(-)nicotine (0.02 mg/kg) was administered 5 min before the radioactive tracers, the uptake of [11C]MPA was decreased by 25% in the thalamus, 19% in the temporal cortex, and 11% in the cerebellum, whereas an increase was found for the uptake of (S)(-)[11C]nicotine and [11C]ABT-418. This finding indicates specific binding of [11C]MPA to nicotinic receptors in the brain in a simple classical displacement study. [11C]MPA seems to be a more promising radiotracer than (S)(-)[11C]nicotine or [11C]ABT-418 for PET studies to characterize nicotinic receptors in the brain

  14. Erlotinib-related bilateral anterior uveitis

    Ali, Kashif; Kumar, Indu; Usman-Saeed, Muniba; Usman Saeed, Muhammad

    2011-01-01

    The authors report the case of a 68-year-old woman with secondary adenocarcinoma of the lungs from an unknown primary. Erlotinib was started which produced symptoms suggestive of uveitis. Erlotinib was stopped and restarted a month later at a lower dose, which resulted in severe bilateral anterior uveitis. The uveitis settled after stopping erlotinib and treatment with topical steroids and cycloplegics. To the best of the authors’ knowledge, this is the first case of erlotinib-related anterio...

  15. An open-label, randomized positron emission tomography (PET) study in healthy male volunteers consisiting of Part A and Part B. Part A: Clinical validation of norepinephrine transporter (NET) PET ligand, (S,S)-[11C]O-methylreboxetine ([11C]MRB) using different doses of oral atomoxetine as NET reuptake inhibitor. Part B: Evaluation of NET occupancy, as measured by [11C]MRB, with multiple dosing regimens of orally administered GSK372475.

    Fowler, Joanna

    2007-08-31

    Results from human studies with the PET radiotracer (S,S)-[(11)C]O-methyl reboxetine ([(11)C](S,S)-MRB), a ligand targeting the norepinephrine transporter (NET), are reported. Quantification methods were determined from test/retest studies, and sensitivity to pharmacological blockade was tested with different doses of atomoxetine (ATX), a drug that binds to the NET with high affinity (K(i)=2-5 nM). METHODS: Twenty-four male subjects were divided into different groups for serial 90-min PET studies with [(11)C](S,S)-MRB to assess reproducibility and the effect of blocking with different doses of ATX (25, 50 and 100 mg, po). Region-of-interest uptake data and arterial plasma input were analyzed for the distribution volume (DV). Images were normalized to a template, and average parametric images for each group were formed. RESULTS: [(11)C](S,S)-MRB uptake was highest in the thalamus (THL) and the midbrain (MBR) [containing the locus coeruleus (LC)] and lowest for the caudate nucleus (CDT). The CDT, a region with low NET, showed the smallest change on ATX treatment and was used as a reference region for the DV ratio (DVR). The baseline average DVR was 1.48 for both the THL and MBR with lower values for other regions [cerebellum (CB), 1.09; cingulate gyrus (CNG) 1.07]. However, more accurate information about relative densities came from the blocking studies. MBR exhibited greater blocking than THL, indicating a transporter density approximately 40% greater than THL. No relationship was found between DVR change and plasma ATX level. Although the higher dose tended to induce a greater decrease than the lower dose for MBR (average decrease for 25 mg=24+/-7%; 100 mg=31+/-11%), these differences were not significant. The different blocking between MBR (average decrease=28+/- 10%) and THL (average decrease=17+/-10%) given the same baseline DVR indicates that the CDT is not a good measure for non-NET binding in both regions. Threshold analysis of the difference between the

  16. Species differences in [11C]clorgyline binding in brain

    [11C]Clorgyline selectively binds to MAO A in the human brain. This contrasts with a recent report that [11C]clorgyline (in contrast to other labeled MAO A inhibitors) is not retained in the rhesus monkey brain . To explore this difference, we compared [11C]clorgyline in the baboon brain before and after clorgyline pretreatment and we also synthesized deuterium substituted [11C]clorgyline (and its nor-precursor) for comparison. [11C]Clorgyline was not retained in the baboon brain nor was it influenced by clorgyline pretreatment or by deuterium substitution, contrasting to results in humans. This suggests a species difference in the susceptibility of MAO A to inhibition by clorgyline and represents an unusual example of where the behavior of a radiotracer in the baboon brain does not predict its behavior in the human brain

  17. Production of [11C]cyanide for the synthesis of indole-3-[1-11C]acetic acid and PET imaging of auxin transport in living plants

    Ellison, P A; Jedele, A. M.; Barnhart, T. E.; Nickles, R J; Murali, D; DeJesus, O.T.

    2015-01-01

    Introduction Since its development by Al Wolf and colleagues in the 1970s1, [11C]cyanide has been a useful synthon for a wide variety of reactions, most notably those producing [1-11C]-labeled amino acids2. However, despite its position as rote gas-phase product, the catalytic synthesis is difficult to optimize and often only perfunctorily dis-cussed in the radiochemical literature. Recently, [11C]CN– has been used in the synthesis of indole-3-[1-11C]acetic acid ([11C]IAA), the principal p...

  18. [Erlotinib-induced acneiform eruption].

    Wahl, R U; Megahed, M

    2013-05-01

    A 73-year-old man has been suffering from a pulmonary adenocarcinoma for three years. He has been treated with the EGF-inhibitor erlotinib for the past 18 months. While taking this medication he developed a progressive papulopustular rash on his face and trunk which later spread to his thighs. Topical treatment with methylprednisolone and nadifloxacin, as well as short courses of systemic doxycycline and ciprofloxacin, led to marked improvement and control of his skin condition. PMID:23535946

  19. Synthesis and preclinical evaluation of carbon-11 labelled N-((5-(4-fluoro-2-[11C]methoxyphenyl)pyridin-3-yl)methyl)cyclopentanamine as a PET tracer for NR2B subunit-containing NMDA receptors

    Introduction: The N-methyl-D-Aspartate (NMDA) receptor plays an important role in learning and memory. Overactivation is thought to play an important role in neurodegenerative disorders such as Alzheimer's disease. Currently, it is not possible to assess N-methyl-D-aspartate receptor (NMDAr) bio-availability in vivo. The purpose of this study was to develop a positron emission tomography (PET) ligand for the NR2B binding site of the NMDA receptor. Methods: N-((5-(4-fluoro-2-methoxyphenyl)pyridin-3-yl)methyl)cyclopentanamine was radiolabelled with carbon-11 in the phenyl moiety. Biodistribution and blocking studies were carried out in anaesthetized mice and in non-anaesthetized rats. Results: N-((5-(4-fluoro-2-[11C]methoxyphenyl)pyridin-3-yl)methyl)cyclopentanamine was prepared in 49 ± 3% (decay-corrected) yield, affording 4.1 ± 0.3 GBq of formulated product at the end of synthesis with a radiochemical purity of > 99% and with a specific activity of 78 ± 10 GBq/μmol. Conclusion: A new NR2B PET ligand was developed in high yield. [11C]4 readily enters the brain and binds to the NR2B subunit-containing NMDAr in the rodent brain. High sigma-1 receptor binding may, however, limit its future application as a PET probe for imaging the NR2B subunit-containing NMDAr. Anaesthesia has an effect on NMDAr function and therefore can complicate interpretation of preclinical in vivo results. In addition, effects of endogenous compounds cannot be excluded. Despite these potential limitations, further studies are warranted to investigate the values of [11C]4 as an NR2B PET ligand

  20. A proposed method for the determination of cerebral regional intermediary glucose metabolism in humans in vivo using specifically labeled 11C-glucose and positron emission transverse tomography (PETT). I. An animal model with 14C-glucose and rat brain autoradiography

    Based upon data obtained with our arterio-venous technique for the determination of cerebral metabolism in humans in vivo we have proposed a method for the determination of cerebral regional intermediary glucose metabolism in humans in vivo using specifically labeled 11C-glucose and positron emission transverse tomography (PETT). In it we would give the subject successive intravenous injections of [3,4-11C] glucose, [2,5-11C] glucose and [1-11C] glucose. There would be a 30 min period of continuous PETT measurements following each injection and a 2 hr interval after the first and second injections. The data would be used with suitable equations and algorithms to estimate for each specific region of the subject's brain the dynamics of the Embden-Meyerhof-Parnas (EMP) and the tricarboxylic acid cycle (TCA) metabolic pathways and the incorporation of glucose carbons into lactate, and the extent of dilution of glucose carbons into lactate, and the extent of dilution of glucose carbons in traversing the TCA with their subsequent incorporation into other carbon pools of the brain (ie, glutamate, glutamine, GABA, alanine). Using 14C as a model for 11C and autoradiographs made with rat brain slices, we have produced an animal model to demonstrate the feasibility of our proposed method. The resulting autoradiographs have provided evidence of the validity of the predictions made from our arterio-venous data. The model was employed to show the selective reductions in the rates of incorporation of specific carbon atoms of glucose into regions of the rat brain and evidence of altered metabolic pathways following a single electroconvulsive shock (ECS) and after a series of nine ECS

  1. Synthesis of [11C]interleukin 8 using a cell-free translation system and L-[11C]methionine

    Positron emission tomography (PET), which requires a compound labeled with a positron emitter radioisotope as an imaging probe, is one of the most useful and valuable imaging modalities in molecular imaging. It has several advantages over other imaging modalities, particularly in sensitive and quantitative investigations of molecular functions and processes in vivo. Recent advances in biopharmaceuticals development have increased interest in practical methods for proteins and peptides labeling with positron emitter radioisotope for PET molecular imaging. Here, we propose a novel approach for preparing positron emitter-labeled proteins and peptides based on biochemical synthesis using a reconstituted cell-free translation system. In this study, [11C]interleukin 8 (IL-8; MW 9.2 kDa) was successfully synthesized by the cell-free system in combination with L-[11C]methionine. The in vitro biochemical reaction proceeded smoothly and gave maximum radioactivity of [11C]IL-8 at 20 min with a radiochemical yield of 63%. Purification of [11C]IL-8 was achieved by conventional cation exchange and ultrafiltration methods, resulting in enough amount of radioactivity with excellent radiochemical purity (>95%) for small-animal imaging. This study clearly demonstrates that cell-free protein production system combined with positron emitter-labeled amino acid holds great promise as a novel approach to prepare radiolabeled proteins and peptides for PET imaging.

  2. Preparation of [11C]-thymidine and [11C]-2'-arabino-2'-fluoro-β-5-methyl-uridine (FMAU) using a hollow fiber membrane bioreactor system

    A series of hollow fiber membranes containing immobilized enzymes were prepared and used in the synthesis of 11C-labelled nucleosides. 11C-Formaldehyde was produced in an alcohol oxidase/catalase bioreactor and circulated through a thymidylate synthase bioreactor with an appropriate substrate to produce the corresponding 11C-nucleotide. These labellled nucleotides were subsequently dephosphorylated in an alkaline phosphatase bioreactor. The bioreactor approach was amenable to hot-cell conditions and yielded 11C-products in higher yield and shorter synthesis times than conventional chemical approaches. (author)

  3. Development of new radioactive labelling methods (3H and 11C) in luteizing hormone (LH) and its releasing hormone (LRF). Study of physico-chemical properties of LRF by circular dichroism and emission spectroscopy

    After a brief review of present knowledge on the hypothalamus-hypophysis this thesis falls into three parts. The first situates the peptide hormones studied in their biological context. Research on the radioactive labelling of hormonal peptides is dealt with in part two which includes, besides the application of already known tritiation methods to particular problems, the description of a new tritium labelling method and the use of carbon 11 for the kinetic distribution study of a hormone. Part three concerns the physico-chemical study of a hypothalamic hormone. As a contribution towards research on the hypophysary gonadotrophic function regulation, the work involved in all the above three sections was directed towards the luteinising hormone (LH) and its hypothalamic release factor (LRF). During the study of this latter the problem of peptides containing tryptophane arose and was consequently investigated

  4. Synthesis of a selective serotonin uptake inhibitor: ( sup 11 C)citalopram

    Dannals, R.F.; Ravert, H.T.; Wilson, A.A.; Wagner, H.N. Jr. (Johns Hopkins Medical Institutions, Baltimore, MD (USA))

    1990-01-01

    Citalopram, a selective serotonin uptake inhibitor, was labeled with {sup 11}C for non-invasive in vivo studies of serotonin uptake sites in the human brain using positron emission tomography. The synthesis was completed in approximately 17 min using ({sup 11}C)methyl iodide as the precursor. The synthesis, purification, characterization, and determination of specific activity are described. (author).

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

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

  6. A radiometabolite study of the serotonin transporter PET radioligand [11C]MADAM

    Introduction: 11C]MADAM is a radioligand suitable for PET studies of the serotonin transporter (SERT). Metabolite analysis in human and non-human plasma samples using HPLC separation has shown that [11C]MADAM was rapidly metabolized. A possible metabolic pathway is the S-oxidation which could lead to SOMADAM and SO2MADAM. In vitro evaluation of these two potential metabolites has shown that SOMADAM exhibited a good affinity for SERT and a good selectivity for SERT over NET and DAT. Methods: Comparative PET imaging studies in non-human primate brain with [11C]MADAM and [11C]SOMADAM were carried out, and plasma samples were analyzed using reverse phase HPLC. We have explored the metabolism of [11C]MADAM in rat brain with a view to understand its possible interference for brain imaging with PET. Results: PET imaging studies in non-human primate brain using [11C]SOMADAM indicated that this tracer does not bind with high amounts to brain regions known to be rich in SERT. The fraction of [11C]SOMADAM in non-human primate plasma was approximately 5% at 4 min and 1% at 15 min after [11C]MADAM injection. HPLC analysis of brain sample after [11C]MADAM injection to rats demonstrated that [11C]SOMADAM was not detected in the brain. Conclusions: 11C]SOMADAM is not superior over [11C]MADAM as a SERT PET radioligand. Nevertheless, [11C]SOMADAM has been identified as a minor labeled metabolite of [11C]MADAM measured in monkey plasma. [11C]SOMADAM was not detected in rat brain

  7. [11C]PR04.MZ, a promising DAT ligand for low concentration imaging: synthesis, efficient 11C-0-methylation and initial small animal PET studies

    Riss, P.J.; Hooker, J.; Alexoff, D.; Kim, Sung-Won; Fowler, J.S.; Roesch, F.

    2009-05-01

    PR04.MZ was designed as a highly selective dopamine transporter inhibitor, derived from natural cocaine. Its binding profile indicates that [{sup 11}C]PR04.MZ may be suited as a PET radioligand for the non-invasive exploration of striatal and extrastriatal DAT populations. As a key feature, its structural design facilitates both, labelling with fluorine-18 at its terminally fluorinated butynyl moiety and carbon-11 at its methyl ester function. The present report concerns the efficient [{sup 11}C]MeI mediated synthesis of [{sup 11}C]PR04.MZ from an O-desmethyl precursor trifluoroacetic acid salt with Rb{sub 2}CO{sub 3} in DMF in up to 95 {+-} 5% labelling yield. A preliminary {mu}PET-experiment demonstrates the reversible, highly specific binding of [{sup 11}C]PR04.MZ in the brain of a male Sprague-Dawley rat.

  8. Synthesis of pyruvate-1-11C as a radiopharmaceutical for tumor imaging

    Pyruvate-1-11C was prepared enzymatically by the exchange reaction of 11CO2 with the carboxyl group of pyruvic acid using pyruvate-ferredoxin oxidoreductase from Clostridium butyricum. 11C-Labeled pyruvate was purified by sublimation in specially made glassware. The radiochemical yield of pure pyruvate-1-11C was 80% 35 min after the end of bombardment. The distribution of 11C in tumor-bearing rabbits after an i.v. injection of pyruvate-1-11C was observed using a gamma camera. In contrast to normal organs, the tumor was positively visualized. We also conducted a number of successful clinical studies. A case of brain tumor which exhibited a positive image on positron-emission tomography (PET) using pyruvate-1-11C is presented. (orig.)

  9. Phase 1 Study of Erlotinib Plus Radiation Therapy in Patients With Advanced Cutaneous Squamous Cell Carcinoma

    Heath, C. Hope; Deep, Nicholas L.; Nabell, Lisle; Carroll, William R.; Desmond, Renee; Clemons, Lisa; Spencer, Sharon; Magnuson, J. Scott [Division of Otolaryngology–Head and Neck Surgery, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama (United States); Rosenthal, Eben L., E-mail: oto@uab.edu [Division of Otolaryngology–Head and Neck Surgery, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama (United States)

    2013-04-01

    Purpose: To assess the toxicity profile of erlotinib therapy combined with postoperative adjuvant radiation therapy in patients with advanced cutaneous squamous cell carcinoma. Methods and Materials: This was a single-arm, prospective, phase 1 open-label study of erlotinib with radiation therapy to treat 15 patients with advanced cutaneous head-and-neck squamous cell carcinoma. Toxicity data were summarized, and survival was analyzed with the Kaplan-Meier method. Results: The majority of patients were male (87%) and presented with T4 disease (93%). The most common toxicity attributed to erlotinib was a grade 2-3 dermatologic reaction occurring in 100% of the patients, followed by mucositis (87%). Diarrhea occurred in 20% of the patients. The 2-year recurrence rate was 26.7%, and mean time to cancer recurrence was 10.5 months. Two-year overall survival was 65%, and disease-free survival was 60%. Conclusions: Erlotinib and radiation therapy had an acceptable toxicity profile in patients with advanced cutaneous squamous cell carcinoma. The disease-free survival in this cohort was comparable to that in historical controls.

  10. Automatic synthesis of [11C]NKY-722 with high specific activity, using anhydrous [11C] methanol as a precursor

    3-(4-allyl-1-piperazinyl)-2,2-dimethylpropyl methyl 1,4-dihydro-2,6-dimethyl- 4-(3-nitrophenyl)-3,5-pyridine dicarboxylate (NKY-722) was labeled with carbon-11 using anhydrous [11C] methanol. Using a computer controlled equipment, a few GBq of [11C] NKY-722 with the specific activity of 120 - 180 GBq/μmol could by synthesized at the radiochemical purity of > 99% in 10 ml of physiological saline containing Polysolvate-80 (1.5 vol%) and ethyl alcohol (0.75 vol%). Preliminary PET experiments using rats and a rhesus monkey have bee done, and very low accumulation of the compound into the brain, however comparatively higher accumulation in the heart were observed. (author)

  11. Dopamine transporter binding in rat striatum: a comparison of [O-methyl-{sup 11}C]{beta}-CFT and [N-methyl-{sup 11}C]{beta}-CFT

    Yoder, Karmen K.; Hutchins, Gary D.; Mock, Bruce H.; Fei, Xiangshu; Winkle, Wendy L. [Department of Radiology, Indiana University School of Medicine, L3-208, Indianapolis, IN 46202 (United States); Gitter, Bruce D.; Territo, Paul R. [Lilly Center for Anatomical and Molecular Imaging, Integrative Biology Division, Lilly Research Laboratories, Greenfield, IN 46140 (United States); Zheng Qihuang [Department of Radiology, Indiana University School of Medicine, L3-208, Indianapolis, IN 46202 (United States)], E-mail: qzheng@iupui.edu

    2009-01-15

    Introduction: Positron emission tomography scanning with radiolabeled phenyltropane cocaine analogs is important for quantifying the in vivo density of monoamine transporters, including the dopamine transporter (DAT). [{sup 11}C]{beta}-CFT is useful for studying DAT as a marker of dopaminergic innervation in animal models of psychiatric and neurological disorders. [{sup 11}C]{beta}-CFT is commonly labeled at the N-methyl position. However, labeling of [{sup 11}C]{beta}-CFT at the O-methyl position is a simpler procedure and results in a shorter synthesis time [desirable in small-animal studies, where specific activity (SA) is crucial]. In this study, we sought to validate that the O-methylated form of [{sup 11}C]{beta}-CFT provides equivalent quantitative results to that of the more commonly reported N-methyl form. Methods: Four female Sprague-Dawley rats were scanned twice on the IndyPET II small-animal scanner, once with [N-methyl-{sup 11}C]{beta}-CFT and once with [O-methyl-{sup 11}C]{beta}-CFT. DAT binding potentials (BP{identical_to}B'{sub avail}/K{sub d}) were estimated for right and left striata with a nonlinear least-squares algorithm, using a reference region (cerebellum) as the input function. Results: [N-Methyl-{sup 11}C]{beta}-CFT and [O-methyl-{sup 11}C]{beta}-CFT were synthesized with 40-50% radiochemical yields (HPLC purification). Radiochemical purity was >99%. SA at end of bombardment was 258{+-}30 GBq/{mu}mol. Average BP values for right and left striata with [N-methyl-{sup 11}C]{beta}-CFT were 1.16{+-}0.08 and 1.23{+-}0.14, respectively. BP values for [O-methyl-{sup 11}C]{beta}-CFT were 1.18{+-}0.08 (right) and 1.22{+-}0.16 (left). Paired t tests demonstrated that labeling position did not affect striatal DAT BP. Conclusions: These results suggest that [O-methyl-{sup 11}C]{beta}-CFT is quantitatively equivalent to [N-methyl-{sup 11}C]{beta}-CFT in the rat striatum.

  12. Effect of tracer metabolism on PET measurement of [11C]pyrilamine binding to histamine H1 receptors

    The present study was carried out to investigate the time course of [11C]pyrilamine metabolism and the degree of entry of metabolites into the brain. PET studies were performed in seven healthy volunteers and arterial plasma concentrations of [11C]pyrilamine and its labeled metabolites were determined. After intravenous injection, [11C]pyrilamine metabolized gradually in the human body, with less than 10% of plasma activity being original radioligand at 60 min. Tracer metabolism markedly affected the input function and the calculated impulse response function of the brain. Rat experiments demonstrated that although metabolites of [11C]pyrilamine might enter the brain, they were not retained for prolonged periods of time. At 30-90 min after injection of [11C]pyrilamine, less than 1% of the radioactivity in the brain was originating from metabolites of [11C]pyrilamine. Based on the rat data, the contribution of 11C-labeled metabolites to total [11C]pyrilamine radioactivity in the human brain was estimated and found to be negligible. These results suggest that the metabolites of [11C]pyrilamine do not accumulate within the cerebral extravascular space and that there is minimal metabolism of [11C]pyrilamine by brain tissue itself. Therefore, [11C]pyrilamine metabolites can be neglected in kinetic analysis, using either a compartmental or a noncompartmental model, of the [11C]pyrilamine binding to histamine H1 receptors. (author)

  13. Quality control of 11C-carfentanil

    To study the quality control of 11C-Carfentanil injection, physical, chemical and biological identification were used. The chemical and radiochemical purity of 11C-Carfentanil Injection were detected by HPLC and Flower Count system; measured the quantity of product by LC-MS, specific activity was calculated later; The PTS was used to detect endotoxin, and other quality control methods were put up to guarantee the security of its clinical application. The produce appeared colorless and transparent, the radiochemical purity was more than 98%, content of the endotoxin was less than 5 EU/mL. The result showed that 11C-Carfentanil injection had fulfilled pharmaceutical quality control request and could be applied safely to animal experiment and clinical diagnosis. (authors)

  14. New halogenated [11C]WAY analogues, [11C]6FPWAY and [11C]6BPWAY--Radiosynthesis and assessment as radioligands for the study of brain 5-HT1A receptors in living monkey

    [Carbonyl-11C]WAY-100635 ([11C]WAY) is an established radioligand for the study of brain serotonin1A (5-HT1A) receptors in living animals and humans with positron emission tomography (PET). There is a recognised need to develop halogenated ligands for 5-HT1A receptors, either for labelling with longer-lived fluorine-18 for more widespread application with PET or with iodine-123 for application with single photon emission tomography (SPET). Here we used autoradiography and PET to assess two new halogenated anlogues of WAY, namely 6BPWAY and 6FPWAY [N-(2-(1-(4-(2-methoxyphenyl)-piperazinyl)ethyl))-N-(2- (6-bromo-/fluoro-pyridinyl))cyclohexanecarboxamide] as prospective radioligands, initially using carbon-11 as the radiolabel. Labelling of 6BPWAY and 6FPWAY with carbon-11 was accomplished by acylation of the corresponding secondary amine precursors with [carbonyl-11C]cyclohexanecarbonyl chloride. After incubation of human brain crysections with [11C]6BPWAY or [11C]6FPWAY, the highest accumulation of radioactivity was observed in cortical areas and the hippocampal formation. Both radioligands had high nonspecific binding. There was a rapid accumulation of radioactivity in the monkey brain after intravenous injection of [11C]6BPWAY and [11C]6FPWAY. High accumulation of radioactivity was observed in the frontal and temporal cortex and the raphe nuclei, areas known to contain a high density of 5-HT1A receptors. The ratios of radioactivity in receptor-rich temporal cortex to that in receptor-poor cerebellum at peak equilibrium were 1.9 (at 10 min) and 3.0 at (at 20 min) for [11C]6BPWAY and [11C]6FPWAY, respectively. In pretreatment experiments with high doses of unlabelled WAY, the level of radioactivity in the frontal and temporal cortex and the raphe nuclei was reduced to the same level as in the cerebellum. Radioactive metabolites of [11C]6FPWAY appeared at a rate similar to those for [11C]WAY, with 17% of the radioactivity in plasma represented by unchanged

  15. [11C]NS8880, a promising PET radiotracer targeting the norepinephrine transporter

    Introduction: Positron emission tomography (PET) imaging of the norepinephrine transporter (NET) is still hindered by the availability of useful PET imaging probes. The present study describes the radiosynthesis and pre-clinical evaluation of a new compound, exo-3-(6-methoxypyridin-2-yloxy)-8-H-8-azabicyclo[3.2.1]octane (NS8880), targeting NET. NS8880 has an in vitro binding profile comparable to desipramine and is structurally not related to reboxetine. Methods: Labeling of NS8880 with [11C] was achieved by a non-conventional technique: substitution of pyridinyl fluorine with [11C]methanolate in a Boc-protected precursor. The isolated [11C]NS8880 was evaluated pre-clinically both in a pig model (PET scanning) and in a rat model (μPET scanning) and compared to (S,S)-[11C]-O-methylreboxetine ([11C]MeNER). Results: The radiolabeling technique yielded [11C]NS8880 in low (<10%) but still useful yields with high purity. The PET in vivo evaluation in pig and rat revealed a rapid brain uptake of [11C]NS8880 and fast obtaining of equilibrium. Highest binding was observed in thalamic and hypothalamic regions. Pretreatment with desipramine efficiently reduced binding of [11C]NS8880. Conclusion: Based on the pre-clinical results obtained so far [11C]NS8880 displays promising properties for PET imaging of NET

  16. EGFR mutation frequency and effectiveness of erlotinib

    Weber, Britta; Hager, Henrik; Sorensen, Boe S;

    2014-01-01

    OBJECTIVES: In 2008, we initiated a prospective study to explore the frequency and predictive value of epidermal growth factor receptor (EGFR) mutations in an unselected population of Danish patients with non-small cell lung cancer offered treatment with erlotinib, mainly in second-line. MATERIAL...

  17. Automated radiochemical synthesis and biodistribution of [11C]l-α-acetylmethadol ([11C]LAAM)

    Long-acting opioid agonists methadone and l-α-acetylmethadol (LAAM) prevent withdrawal in opioid-dependent persons. Attempts to synthesize [11C]-methadone for PET evaluation of brain disposition were unsuccessful. Owing, however, to structural and pharmacologic similarities, we aimed to develop [11C]LAAM as a PET ligand to probe the brain exposure of long-lasting opioids in humans. This manuscript describes [11C]LAAM synthesis and its biodistribution in mice. The radiochemical synthetic strategy afforded high radiochemical yield, purity and specific activity, thereby making the synthesis adaptable to automated modules. - Highlights: • Radiochemical synthesis of opioid [11C]l-α-acetylmethadol (LAAM) described for the first time. • High radiochemical yield, purity and specific activity. • Easily reproducible and adaptable synthesis to any C-11 automated modules. • [11C]LAAM utility as a PET radiopharmaceutical for assessing brain penetration

  18. Synthesis of racemic, R- and S-[1-11C]-β-hydroxybutyric acid

    Racemic, R- and S-β-hydroxybutyric acid were labelled with 11C in the carboxylic position by a two-step stereospecific synthesis starting with carrier-added [11C]cyanide and R/S, R- or S-propylene oxide. Hydrolysis of the intermediate nitrile with hydrochloric acid gave racemic [1-11C]-β-hydroxybutyric acid and R- or S-[1-11C]-β-hydroxybutyric acid with an enantiomeric excess of 87-97%. The total synthesis time (including HPLC purification) was 45-50 min from end of trapping. The isolated decay-corrected radiochemical yield was 20-30% based on [11C]cyanide. The radiochemical purity of the products was > 99%]. (author)

  19. Radiosynthesis of (tetrazoyl-11C)irbesartan, a non-peptidic angiotensin II antagonist

    With the aim of visualizing myocardial angiotensin II receptors (ATI subtypes), [tetrazoyl-11C]2-n-butyl-1-[(2'-(1H-tetrazole-5-yl)-1,1'-biphenyl-4-yl)methyl]-4-spirocyclo-pentane-2-imidazoline-5-one ([tetrazoyl-11C]irbesartam (SR47436/BMS-186295)) 11 was synthesized in one pot in four steps from [11C]hydrogen cyanide. The labelling process which yielded [tetrazoyl-11C]irbesartan is described in detail and could be applied to the labelling of other ligands which possess the (1H-tetrazole-5-yl) moiety. Positron emission tomography (PET) studies were performed in dogs. Heart, lung and blood time-activity curves did not change. Therefore this new radioligand is not suitable for studying myocardial angiotensin II receptors with PET. (authors)

  20. Pharmacological evaluation of [11c]donepezil as tracer for visualization of acetylcholinesterase by PET

    Donepezil is a highly potent and selective reversible acetylcholinesterase inhibitor. [11C]Donepezil is prepared by methylation with [11C]CH3I of the corresponding 6'-O-desmethylprecursor. Tissue distribution in mice revealed a high uptake in brain and rapid clearance from the blood. Metabolization studies in mice indicated the formation of one 11C-labeled polar metabolite that didn't penetrate the blood-brain barrier. Regional brain distribution in rabbits didn't reflect the measured achetylcholinesterase distribution in rabbit brain

  1. Interstitial lung disease associated to erlotinib treatment: a case report

    del Castillo, Yolanda; Espinosa, Paulina; Bodí, Fernanda; Alcega, Raquel; Muñoz, Emma; Rabassó, Carlos; Castander, David

    2010-01-01

    Introduction Few cases of pulmonary toxicity related to epidermal growth factor receptor-targeted agents have been described. Case presentation We report a case of a 63-year-old white male with stage IV non-small cell lung cancer treated with erlotinib who developed a interstitial lung disease. Conclusion Respiratory symptoms during treatment with erlotinib should alert clinicians to rule out pulmonary toxicity. Early erlotinib withdrawal and corticoid administration were successful.

  2. Synthesis of 11C-methylated inulin as a radiopharmaceutical for imaging brain edema and pulmonary edema

    11C-methylated inulin, supposedly useful for imaging of brain edema and pulmonary edema, was prepared using cyclotron produced 11CO2. The synthesis consists of the production of 11C-methyl iodide and its coupling with inulin alkoxide sodium in dimethylsulfoxide as solvent. 11C labeled inulin was purified by alcohol precipitation. The radiochemical yield of pure 11C-inulin was 34% of 11CO2 30 min after the end of bombardment. The blood clearance and body distribution of 11C was observed in rabbits after i.v. injection of 11C-inulin. The blood clearance curve was composed of a sum of three exponential functions. The gamma camera image showed that the 11C activity in blood moved quickly to kidneys and urine and a small dose of radioactivity remained persistently in edematous tissues, i.e. the edematous lung tissues produced by oleic acid treatment. (orig.)

  3. Automated chemoenzymatic synthesis of no-carrier-added [carbonyl-11C]propionyl L-carnitine for pharmacokinetic studies

    Propionyl-L-carnitine (PLC) is under development as a therapeutic for the treatment of peripheral artery disease, coronary heart disease and chronic heart failure. Three methods were examined for labelling PLC in its propionyl group with positron-emitting carbon-11 (t1/2 = 20.3 min), one chemical and two chemoenzymatic. The former was based on the preparation of [11C]propionyl chloride as labelling agent via 11C-carboxylation of ethylmagnesium bromide with cyclotron-produced [11C]carbon dioxide and subsequent chlorination. Reaction of carrier-added [11C]propionyl chloride with L-carnitine in trifluoroacetic acid gave [11C]PLC in 12% radiochemical yield (decay-corrected) from cyclotron-produced [11C]carbon dioxide. However, the radiosynthesis was unsuccessful at the no-carrier added (NCA) level of specific radioactivity. [11C]Propionate, as a radioactive precursor for chemoenzymatic routes, was prepared via carboxylation of ethylmagnesium bromide with [11C]carbon dioxide and hydrolysis. NCA [11C]PLC was prepared in 68 min in 14% radiochemical yield (decay-corrected) from [11C]propionate via sequential conversions catalysed by acetate kinase, phosphotransacetylase and carnitine acetyltransferase. A superior chemoenzymatic synthesis of NCA [11C]PLC was developed, based on the use of a novel supported Grignard reagent for the synthesis of [11C]propionate and conversions by S-acetyl-CoA synthetase and carnitine acetyltransferase. This gave an overall radiochemical yield of 30-48% (decay-corrected). This synthesis was automated for radiation safety and provides pure NCA [11C]PLC in high radioactivities ready for intravenous administration within 25 min from radionuclide production. The [11C]PLC is suitable for pharmacokinetic studies in human subjects with PET and the elucidation of the fate of the propionyl group of PLC in vivo. (Author)

  4. Synthesis of [[sup 11]C] platelet-activating factor (PAF) analogs for in vivo imaging of PAF receptors

    Sasaki, T.; Ishiwata, K. (Tokyo Metropolitan Inst. of Gerontology, Itabishi (Japan)); Karasawa, K. (Teikyo Univ., Kanagawa (Japan). Faculty of Pharmaceutical Sciences) (and others)

    1993-10-01

    [1-O-hexadecyl-2-O-N], N-dimethylcarbamoyl-sn-glycero-3-phosphocholine[choline methyl-[sup 11]C] ([[sup 11]C])dimethylcarbamoyl-platelet-activating factor (PAF) and 1-O-hexadecyl-2-O-acetyl-sn-glycero-3-phosphocholine[choline methyl-[sup 11]C] ([[sup 11]C]C[sub 16]-PAF) were synthesized as follows. Each of non-labeled dimethylcarbamoyl-PAF and C[sub 16]-PAF was treated with sodium benzene thiolate to derive their desmethyl-precursors containing a dimethylphosphoethanolamine at sn-3. [sup 11]C-Labeled dimethylcarbamoyl-PAF and C[sub 16]-PAF were synthesized by methylation of the respective desmethyl-precursors using [[sup 11]C]CH[sub 3]I. The radiochemical yield of methylation in [[sup 11]C]dimethylcarbamoyl-PAF and [[sup 11]C]C[sub 16]-PAF was about 15 and 10% (decay corrected), respectively. To study the stability to enzymatic hydrolysis, [[sup 11]C]dimethylcarbamoyl-PAF or [[sup 11]C]C[sub 16]-PAF was incubated with mouse plasma at 37[sup o]C. [[sup 11]C]Dimethylcarbamoyl-PAF remained intact for 60 min. On the other hand, almost all the radioactivity of [[sup 11]C]C[sub 16]-PAF was converted into [[sup 11]C]C[sub 16]-lyso-PAF in 5 min. These observations indicate that [[sup 11]C]dimethylcarbamoyl-PAF can be a suitable probe for in vivo imaging of PAF receptors. (author).

  5. Bilateral anterior uveitis secondary to erlotinib

    Lim, Lik Thai; Blum, Robert Alexander; Cheng, Chee Peng; Hanifudin, Abdul

    2010-01-01

    Bilateral anterior uveitis secondary to erlotinib phone: +44-784-3617788 (Lim, Lik Thai) (Lim, Lik Thai) Ophthalmology Department, Gartnavel General Hospital - Great Western Road - G12 0YN - Glasgow - UNITED KINGDOM (Lim, Lik Thai) Ophthalmology Department, Gartnavel General Hospital - Great Western Road - G12 0YN - Glasgow - UNITED KINGDOM (Blum, Robert Alexander) Ophthalmology Department, Gartnavel General Hospital - Great Western Road - G12 0YN - G...

  6. [[sup 11]C](+)McN5652 as a radiotracer for imaging serotonin uptake sites with PET

    Suehiro, M.; Scheffel, U.; Ravert, H.T.; Dannals, R.F.; Wagner, H.N. Jr. (The Johns Hopkins Medical Institutions, Baltimore, MD (United States))

    1993-01-01

    The in vivo behavior of the stereoisomers of [[sup 11]C]McN5652, a highly potent serotonin (5-HT) uptake blocker, was determined to evaluate their utility as radiotracers for imaging 5-HT uptake sites by positron emission tomography (PET). After intravenous injection into mice, [[sup 11]C](+)MnN5652 showed markedly higher uptake and longer retention in regions with high density of 5-HT uptake sites than the [[sup 11]C]-labeled racemic mixture, while [[sup 11]C]([minus])McN5652 washed out rapidly. With the [[sup 11]C](+)-enantiomer, the ratio between hypothalamus and cerebellum reached 6 at 90 minutes. The binding of [[sup 11]C](+)McN5652 was inhibited by 45-73% by pre-injection of 5 mg/kg of paroxetine, a selective 5-HT uptake blocker, in all regions examined except cerebellum where no significant effect of the drug was observed. [[sup 11]C]([minus])McN5652 showed no specific binding in any of the regions. The [[sup 11]C]-labeled cis isomer, [[sup 11]C]McN5655, revealed surprisingly low brain penetration and showed no significantly higher uptake in regions of interest than cerebellum. These results suggest that [[sup 11]C](+)McN56542 is a promising candidate as a PET radiotracer for studying 5-HT uptake sites in vivo.

  7. An automated radiosynthesis of 2-[11C]thymidine using anhydrous [11C]urea derived from [11C]phosgene

    2-[11C]Thymidine has been produced from [11C]methane via [11C]phosgene and [11C]urea. Anhydrous [11C]urea was prepared from [11C]phosgene by reaction with liquid ammonia. This novel approach avoids the problems associated with the synthesis of anhydrous [11C]urea from [11C]cyanide. A fully automated system based on a modular approach and under PLC control has been developed. The system provides 2-[11C]thymidine reliably and reproducibly for clinical PET studies. The radiosynthesis takes 45-50 min from [11C]methane and the average yield was 1.5-3.3 GBq (40-90 mCi). The specific radioactivity was typically in the range 29.6-51.8 GBq μmol-1 (0.8-1.4 Ci μmol-1) at EOS corresponding to 6-12 μg of stable thymidine. The radiochemical yield of 2-[11C]thymidine was ca. 14% from [11C]methane

  8. Erlotinib-Associated Acute Pneumonitis: Report of Two Cases

    Bobbak Vahid

    2007-01-01

    Full Text Available Two cases of erlotinib-associated acute pneumonitis are described. The first patient was started on erlotinib treatment for metastatic non-small cell lung cancer. The second patient was treated with erlotinib for metastatic adenocarcinoma of unknown origin. Both patients developed dyspnea and hypoxemia five to six days after initiation of erlotinib treatment. In both cases, computed tomography scan of the chest showed extensive bilateral ground-glass infiltrates consistent with pneumonitis. In both patients, acute pneumonitis resulted in respiratory failure requiring intubation and mechanical ventilation. Diffuse alveolar hemorrhage was excluded by bronchoscopy in both cases. Bronchoalveolar lavage cultures were negative. Erlotinib treatment was stopped and both patients were treated with corticosteroids. The first patient improved gradually and finally was discharged to a rehabilitation centre, but unfortunately the second patient died of Klebsiella sepsis. Naranjo causality scale in both cases suggested a probable association between erlotinib and pneumonitis. Literature on erlotinib-associated pneumonitis is sparse. The clinical presentation and radiographic findings of erlotinib-associated acute pneumonitis are described.

  9. Phase II trials of erlotinib or gefitinib in patients with recurrent meningioma.

    Norden, Andrew D; Raizer, Jeffrey J; Abrey, Lauren E; Lamborn, Kathleen R; Lassman, Andrew B; Chang, Susan M; Yung, W K Alfred; Gilbert, Mark R; Fine, Howard A; Mehta, Minesh; Deangelis, Lisa M; Cloughesy, Timothy F; Robins, H Ian; Aldape, Kenneth; Dancey, Janet; Prados, Michael D; Lieberman, Frank; Wen, Patrick Y

    2010-01-01

    There are no established treatments for recurrent meningioma when surgical and radiation options are exhausted. The epidermal growth factor receptor (EGFR) is often over-expressed in meningiomas and may promote tumor growth. In open label, single arm phase II studies of the EGFR inhibitors gefitinib (NABTC 00-01) and erlotinib (NABTC 01-03) for recurrent malignant gliomas, we included exploratory subsets of recurrent meningioma patients. We have pooled the data and report the results here. Patients with recurrent histologically confirmed meningiomas with no more than 2 previous chemotherapy regimens were treated with gefitinib 500 mg/day or erlotinib 150 mg/day until tumor progression or unacceptable toxicity. Twenty-five eligible patients were enrolled with median age 57 years (range 29-81) and median Karnofsky performance status (KPS) score 90 (range 60-100). Sixteen patients (64%) received gefitinib and 9 (36%) erlotinib. Eight patients (32%) had benign tumors, 9 (36%) atypical, and 8 (32%) malignant. For benign tumors, the 6-month progression-free survival (PFS6) was 25%, 12-month PFS (PFS12) 13%, 6-month overall survival (OS6) 63%, and 12-month OS (OS12) 50%. For atypical and malignant tumors, PFS6 was 29%, PFS12 18%, OS6 71%, and OS12 65%. The PFS and OS were not significantly different by histology. There were no objective imaging responses, but 8 patients (32%) maintained stable disease. Although treatment was well-tolerated, neither gefitinib nor erlotinib appear to have significant activity against recurrent meningioma. The role of EGFR inhibitors in meningiomas is unclear. Evaluation of multi-targeted inhibitors and EGFR inhibitors in combination with other targeted molecular agents may be warranted. PMID:19562255

  10. Palladium mediated 11C-cyanation and characterization in the non-human primate brain of the novel mGluR5 radioligand [11C]AZD9272

    Introduction: The aims of the present positron emission tomography (PET) study were to set up a system for 11C-cyanation labeling of the selective mGluR5-antagonist [11C]AZD9272 and to perform the first in vivo characterization of [11C]AZD9272 binding in cynomolgus monkeys. Methods: [11C]AZD9272 was labeled using palladium mediated 11C-cyanation. Altogether seven PET measurements were performed in three cynomolgus monkeys including baseline and co-injection experiments with unlabelled AZD9272 (0.04 and 0.4 mg/kg). Radiometabolites in plasma were measured using HPLC. Results: [11C]AZD9272 was prepared in over 50% incorporation yield from hydrogen [11C]cyanide in a total synthesis time of 45–50 min. The radiochemical purity of the radioligand in its final formulation was high (> 99%) and the mean specific radioactivity was 47 GBq/ μmol (1278 Ci/mmol, n = 7) calculated at end of bombardment (EOB). In the baseline measurements 10% of the total injected radioactivity was present in monkey brain at five minutes after i.v. injection. The radioactivity concentration was high in the caudate, cingulate gyrus and thalamus whereas it was moderate in the temporal cortex and lower for the cerebellum. After co-injection with cold AZD9272 the binding of [11C]AZD9272 was reduced in a dose-dependent fashion. Analysis of radiometabolites showed relatively slow metabolism and resulted only in hydrophilic radiometabolites. Conclusion: A fast and efficient method was developed to label AZD9272 with 11C. PET-examination in Cynomolgus monkeys showed that [11C]AZD9272 entered the brain to a high extent, that binding was saturable and that the regional radioactivity pattern was in accordance with the known distribution of mGluR5. The results support further examination of [11C]AZD9272 binding in human subjects

  11. Development of additive [11C]CO2 target system in the KOTRON-13 cyclotron and its application for [11C]radiopharmaceutical production

    Moon, Byung Seok; Lee, Hong Jin; Lee, Won Kyung; Hur, Min Goo; Yang, Seung Dae; Lee, Byung Chul; Kim, Sang Eun

    2015-08-01

    The KOTRON-13 cyclotron, which was developed in South Korea for the production of medical radioisotopes, has the structural limitation of only one beam-output port, restricting the production of the carbon-11 isotope. In the present study, we investigate the design of a switchable target system and develop an effective carbon-11 target in the KOTRON-13 cyclotron, for combination with the fluorine-18 target. The target system was designed by introducing a sliding-type element between the fluorine-18 and carbon-11 targets, a tailor-made C-11 target and its cooling system. For the efficient production of [11C]CO2, the desirable target shape and internal volume were determined by a Stopping and Range of Ions in Matter (SRIM) simulation program, and the target grid was modified to resist the cavity pressure during beam irradiation. We evaluated the [11C]CO2 production while varying the material and thickness of the target foil, oxygen content of the nitrogen gas, and target loading pressure. Using sliding-type equipment including an additional gate valve and a high vacuum in a beam line, the bi-directional conversion between the fluorine-18 and carbon-11 targets was efficient regarding the accurate beam irradiation on both targets. The optimal [11C]CO2 production for 30 min irradiation at 60 μA (86.6 ± 1.7 GBq in the target at EOB) was observed at a thickness of 19 μm with HAVAR® material as a target foil and a target loading pressure of 24 bar with nitrogen plus 300 ppb of oxygen gas. Additionally, the coolant cavity system in the target grid and target chamber is useful to remove the heat transferred to the target body by the internal convection of water and thereby ensure the stability of the [11C]CO2 production under a high beam current. In the application of C-11 labeled radiopharmaceuticals such as [11C]PIB, [11C]DASB, [11C]PBR28, [11C]Methionine and [11C]Clozapine, the radiochemical yields were shown to be 25-38% (decay corrected) with over 166 GBq/μmol of

  12. Development of additive [11C]CO2 target system in the KOTRON-13 cyclotron and its application for [11C]radiopharmaceutical production

    The KOTRON-13 cyclotron, which was developed in South Korea for the production of medical radioisotopes, has the structural limitation of only one beam-output port, restricting the production of the carbon-11 isotope. In the present study, we investigate the design of a switchable target system and develop an effective carbon-11 target in the KOTRON-13 cyclotron, for combination with the fluorine-18 target. The target system was designed by introducing a sliding-type element between the fluorine-18 and carbon-11 targets, a tailor-made C-11 target and its cooling system. For the efficient production of [11C]CO2, the desirable target shape and internal volume were determined by a Stopping and Range of Ions in Matter (SRIM) simulation program, and the target grid was modified to resist the cavity pressure during beam irradiation. We evaluated the [11C]CO2 production while varying the material and thickness of the target foil, oxygen content of the nitrogen gas, and target loading pressure. Using sliding-type equipment including an additional gate valve and a high vacuum in a beam line, the bi-directional conversion between the fluorine-18 and carbon-11 targets was efficient regarding the accurate beam irradiation on both targets. The optimal [11C]CO2 production for 30 min irradiation at 60 μA (86.6 ± 1.7 GBq in the target at EOB) was observed at a thickness of 19 μm with HAVAR® material as a target foil and a target loading pressure of 24 bar with nitrogen plus 300 ppb of oxygen gas. Additionally, the coolant cavity system in the target grid and target chamber is useful to remove the heat transferred to the target body by the internal convection of water and thereby ensure the stability of the [11C]CO2 production under a high beam current. In the application of C-11 labeled radiopharmaceuticals such as [11C]PIB, [11C]DASB, [11C]PBR28, [11C]Methionine and [11C]Clozapine, the radiochemical yields were shown to be 25–38% (decay corrected) with over 166 GBq/μmol of

  13. Development of additive [{sup 11}C]CO{sub 2} target system in the KOTRON-13 cyclotron and its application for [{sup 11}C]radiopharmaceutical production

    Moon, Byung Seok; Lee, Hong Jin [Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam 463-707 (Korea, Republic of); Lee, Won Kyung [Technical Support Team, Duchembio, Seoul 121-844 (Korea, Republic of); Hur, Min Goo; Yang, Seung Dae [Radiation Instrumentation Research Division, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Lee, Byung Chul, E-mail: leebc2001@gmail.com [Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam 463-707 (Korea, Republic of); Center for Nanomolecular Imaging and Innovative Drug Development, Advanced Institutes of Convergence Technology, Suwon 443-270 (Korea, Republic of); Kim, Sang Eun [Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam 463-707 (Korea, Republic of); Center for Nanomolecular Imaging and Innovative Drug Development, Advanced Institutes of Convergence Technology, Suwon 443-270 (Korea, Republic of); Smart Humanity Convergence Center, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 443-270 (Korea, Republic of)

    2015-08-01

    The KOTRON-13 cyclotron, which was developed in South Korea for the production of medical radioisotopes, has the structural limitation of only one beam-output port, restricting the production of the carbon-11 isotope. In the present study, we investigate the design of a switchable target system and develop an effective carbon-11 target in the KOTRON-13 cyclotron, for combination with the fluorine-18 target. The target system was designed by introducing a sliding-type element between the fluorine-18 and carbon-11 targets, a tailor-made C-11 target and its cooling system. For the efficient production of [{sup 11}C]CO{sub 2}, the desirable target shape and internal volume were determined by a Stopping and Range of Ions in Matter (SRIM) simulation program, and the target grid was modified to resist the cavity pressure during beam irradiation. We evaluated the [{sup 11}C]CO{sub 2} production while varying the material and thickness of the target foil, oxygen content of the nitrogen gas, and target loading pressure. Using sliding-type equipment including an additional gate valve and a high vacuum in a beam line, the bi-directional conversion between the fluorine-18 and carbon-11 targets was efficient regarding the accurate beam irradiation on both targets. The optimal [{sup 11}C]CO{sub 2} production for 30 min irradiation at 60 μA (86.6 ± 1.7 GBq in the target at EOB) was observed at a thickness of 19 μm with HAVAR® material as a target foil and a target loading pressure of 24 bar with nitrogen plus 300 ppb of oxygen gas. Additionally, the coolant cavity system in the target grid and target chamber is useful to remove the heat transferred to the target body by the internal convection of water and thereby ensure the stability of the [{sup 11}C]CO{sub 2} production under a high beam current. In the application of C-11 labeled radiopharmaceuticals such as [{sup 11}C]PIB, [{sup 11}C]DASB, [{sup 11}C]PBR28, [{sup 11}C]Methionine and [{sup 11}C]Clozapine, the radiochemical

  14. Tracers development for the PET study of nicotinic receptors: [11C]-mecamylamine and [11C]-SIB 1553A. Tritium and carbon-11 radiolabelling of a serine proteinase inhibitor: the t-PAstop

    In order to develop radiotracers for the Positron Emission Tomography (PET), we labelled both the mecamylamine and SIB-1553A with carbon-11 to study the nicotinic cholinergic receptors (nAChRs). The radiosynthesis of [11C]-t-PAstop and the labelling with tritium of one analogue were realized for cerebral ischemia PET studies. The [11C]-mecamylamine, a non-competitive and non-selective nAChRs antagonist was synthesized in 45 min via a N-[11C]-methylation reaction. In the rat brain, the ex vivo studies showed no radio-metabolite 45 min after the injection of [11C]-mecamylamine. The uptake kinetics in the rat brain or in vivo by PET in the anesthetized baboon or in the conscious monkey, reached a plateau around 45-50 min after injection. However, the saturation or displacement experiments did not permit to exhibit nor a significant difference of labelling between the different cerebral regions nor a specific uptake. In consequence, the [11C]-mecamylamine was not an appropriate radioligand for nAChRs PET study. The labelling of [11C]-SIB 1553A, a selective agonist for the nicotinic β4 subunit, required the synthesis in 5 steps (56% overall yield) of precursor for the incorporation of carbon-11. The radiosynthesis was performed in 36 min by a N-[11C]-methylation reaction (yield: 75%). The [11C]-t-PAstop was obtained from [11C]-KCN with yields from 80 to 90%. For the first time with carbon-11, the formation of an amidine group was realized from a nitrile group. The labelling by isotopic exchange of hydrogen by tritium of the t-PAstop did not permit to obtain the [3H]-t-PAstop but a tritiated analogue. This compound will be used to study its vectorization by micro-encapsulation. (author)

  15. The synthesis of [O-methyl-11C]venlafaxine: a non-classical, fast-acting antidepressant

    As part of our program to develop PET tracers for the 5-HT reuptake site, venlafaxine, a non-classical, fast-acting antidepressant, was selected as a candidate for labelling with 11C for in vivo evaluation. [O-methyl-11C]venlafaxine was produced by the alkylation of O-desmethyl venlafaxine with [11C]methyl iodide followed by HPLC purification and formulation. Radiochemically pure [O-methyl-11C]venlafaxine was obtained in a 30 ± 5% decay corrected radiochemical yield and a specific activity > 50 GBq/μmol(1.4 Ci/μmol) at the end of synthesis. For a typical production starting with 46 GBq (1.3 Ci) [11C]CO2, 5.2 GBq (140 mCi) [O-methyl-11C]venlafaxine was obtained as a sterile, formulated solution in a synthesis time of 30 min (counted from EOB). (Author)

  16. Regional cerebral distribution of 11C-methyl-D-glucose in man

    The reported study was undertaken to investigate if MG is useful to study glucose metabolism in humans, as suggested previously. For that purpose MG was labelled with 11C, and positron emission tomograms were obtained in healthy volunteers and patients with brain disorders. (Auth.)

  17. In vivo evaluation of [11C]SA4503 as a PET ligand for mapping CNS sigma1 receptors

    The potential of the 11C-labeled selective sigma1 receptor ligand 1-(3,4-dimethoxyphenethyl)-4-(3-phenylpropyl)piperazine ([11C]SA4503) was evaluated in vivo as a positron emission tomography (PET) ligand for mapping sigma1 receptors in rats. SA4503 is known to have a high affinity (IC50 17.4 nM) and a higher selectivity (sigma1/sigma2=103) for the sigma1 receptor. A high and increasing brain uptake of [11C]SA4503 was found. Pre-, co- and postinjection of cold SA4503 significantly decreased uptake of [11C]SA4503 in the brain, spleen, heart, lung, and kidney in which sigma receptors are present as well as in the skeletal muscle. In the blocking study with one of four sigma receptor ligands including haloperidol, (+)-pentazocine, SA4503, and (-)-pentazocine (in the order of their affinity for sigma1 receptor subtype), SA4503 and haloperidol significantly reduced the brain uptake of [11C]SA4503 to approximately 30% of the control, but the other two benzomorphans did not. A high specific uptake of [11C]SA4503 by the brain was also confirmed by ex vivo autoradiography (ARG) and PET. Ex vivo ARG showed a higher uptake in the vestibular nucleus, temporal cortex, cingulate cortex, inferior colliculus, thalamus, and frontal cortex, and a moderate uptake in the parietal cortex and caudate putamen. Peripherally, the blocking effects of the four ligands depended on their affinity for sigma1 receptors. No 11C-labeled metabolite was detected in the brain 30 min postinjection, whereas approximately 20% of the radioactivity was found as 11C-labeled metabolites in plasma. These results have demonstrated that the 11C-labeled sigma1 receptor ligand [11C]SA4503 has a potential for mapping sigma1 receptors in the central nervous system and peripheral organs

  18. Low background and high contrast PET imaging of amyloid-β with [11C]AZD2995 and [11C]AZD2184 in Alzheimer's disease patients

    The aim of this study was to evaluate AZD2995 side by side with AZD2184 as novel PET radioligands for imaging of amyloid-β in Alzheimer's disease (AD). In vitro binding of tritium-labelled AZD2995 and AZD2184 was studied and compared with that of the established amyloid-β PET radioligand PIB. Subsequently, a first-in-human in vivo PET study was performed using [11C]AZD2995 and [11C]AZD2184 in three healthy control subjects and seven AD patients. AZD2995, AZD2184 and PIB were found to share the same binding site to amyloid-β. [3H]AZD2995 had the highest signal-to-background ratio in brain tissue from patients with AD as well as in transgenic mice. However, [11C]AZD2184 had superior imaging properties in PET, as shown by larger effect sizes comparing binding potential values in cortical regions of AD patients and healthy controls. Nevertheless, probably due to a lower amount of nonspecific binding, the group separation of the distribution volume ratio values of [11C]AZD2995 was greater in areas with lower amyloid-β load, e.g. the hippocampus. Both AZD2995 and AZD2184 detect amyloid-β with high affinity and specificity and also display a lower degree of nonspecific binding than that reported for PIB. Overall [11C]AZD2184 seems to be an amyloid-β radioligand with higher uptake and better group separation when compared to [11C]AZD2995. However, the very low nonspecific binding of [11C]AZD2995 makes this radioligand potentially interesting as a tool to study minute levels of amyloid-β. This sensitivity may be important in investigating, for example, early prodromal stages of AD or in the longitudinal study of a disease modifying therapy. (orig.)

  19. Evaluation of clinial usefulness of [sup 11]C-methionine positron emission tomography ([sup 11]C-MET-PET) as a tool for liver functional imaging

    Enomoto, Kazuo; Matsui, Yoshifumi; Okazumi, Shinichi (Chiba Univ. (Japan). School of Medicine) (and others)

    1994-03-01

    We studied [sup 11]C-MET-PET in 17 clinical cases, 10 patients with obstructive jaundice and 7 normal volunteers, and analyzed its efficacy for the evaluation of hepatic functional reserve in major hepatectomy candidates. Differential absorption ratio (DAR) of [sup 11]C was compared to the hepatic protein synthesis rate (HPS), which is measured as the incorporation rate of [sup 3]H-labeled leucine in protein fraction, using needle biopsied liver specimen obtained from each hepatic segment. In the cases of normal liver function, DAR was well correlated with HPS. Also in jaundice cases with two exceptions, low HPS segment was demonstrated as low DAR segment. Consequently, MET-PET images could clearly provide functional liver imaging. After injection of [sup 11]C-MET, the increase in rate of radioactivity of [sup 11]C in plasma protein fraction was higher in jaundice cases than in normal volunteers, which is in accord with the results of our former study that cholestatic liver has accelerated protein synthesis rate. In summary, since [sup 11]C-MET-PET could demonstrate liver functional imaging, it might be a possible tool for liver function assessment in major hepatectomy candidates. (author).

  20. 11C-2-deoxy-D-glucose: Synthesis and preliminary comparison with 11C-D-glucose as a tracer for cerebral energy metabolism in PET studies

    11C-2-Deoxy-D-glucose has been prepared by the reaction of 11C-hydrogen cyanide with a stable precursor, 1-deoxy-2,3:4,5-di-O-isopropylidine-1-iodo-D-arabitol, thereby avoiding the synthesis of starting material immediately prior to labeling. Fast, efficient, and reproducible solvent change from dimethyl sulfoxide to ether by flash chromatography enabled the use of diisobutylaluminium hydride in the reduction of the intermediate nitrile. Hydrolysis of the imine-aluminum complex with sulfuric acid, removal of the isopropylidine protecting groups with formic acid, and HPLC purifiction with an Aminex HPX-87P column yielded 11C-2-deoxy-D-glucose in an aqueous solution, sterile, pyrogen-free, and ready for use in human studies. The radiochemical yield was proportional20% after a synthesis time of 50 min. The 11C-2-deoxy-D-glucose thus obtained is presently being compared with photosynthetically prepared 11C-D-glucose in PET studies of cerebral metabolism. A preliminary report of the regional cerebral metabolic rate of glucose obtained with the two tracers in a healthy subject with visual stimulation is presented. (orig.)

  1. 5-Fluoro-[β-11C]-L-tryptophan is a functional analogue of 5-hydroxy-[β-11C]-L-tryptophan in vitro but not in vivo

    Introduction: 5-Hydroxy-[β-11C]-L-tryptophan ([11C]HTP) is an established positron emission tomography (PET) imaging agent for neuroendocrine tumors (NETs). It has also been used for other clinical research purposes in neurology and diabetes. However, its widespread use is limited by the short physical half-life of the radionuclide and a difficult radiosynthesis. Therefore, a Fluorine-18 labeled analogue, 5-[18F]Fluoro-L-tryptophan ([18F]FTRP), has been proposed as a functional analogue. There is no published method for the synthesis of L-[18F]FTRP. We have therefore developed a synthesis of 5-fluoro-[β-11C]-L-tryptophan ([11C]FTRP), based on the existing chemo-enzymatic method for [11C]HTP and evaluated the potential usefulness of radiolabeled FTRP as a substitute for [11C]HTP. Methods: The in vitro and in vivo behavior of [11C]FTRP, including the dependence of key enzymes in the serotonergic metabolic pathway, was investigated in NET cell lines, NET xenograft carrying immunodeficient mice, normal rats and in non-human primate. [11C]HTP was used for direct comparison. Results: Uptake of [11C]FTRP in NET cell lines in vitro was mediated by enzymes involved in serotonin synthesis and metabolism, similar to [11C]HTP. In vivo biodistribution, either in rodent or non-human primate, was not affected by selectively inhibiting enzymatic steps in the serotonergic metabolic pathway. Conclusion: [11C]FTRP has in vitro biological function similar to that of [11C]HTP. However, this function is not retained in vivo as shown by biodistribution and PET/CT studies. Radiolabeled FTRP is thus not likely to provide an advantage over [11C]HTP in PET imaging in oncology, neurology or diabetes

  2. [11C]NNC 22-0215, a metabolically stable dopamine D1 radioligand for PET

    NNC 22-0215 has been found to be a metabolically stable dopamine D1 antagonist with high affinity and selectivity for D1 receptors in vitro. We prepared [11C]NNC 22-0215 with a specific radioactivity of about 50 GBq/μmol at time of administration. In PET experiments with [11C]NNC 22-0215 there was a rapid uptake of radioactivity in the cynomolgus monkey brain (1.8% of total radioactivity injected). Radioactivity accumulated most markedly in the striatum and the neocortex. The striatum to cerebellum ratio was about 4, with specific binding that remained at a plateau level from 50 min to 100 min after injection. Binding in the striatum and neocortex was markedly displaced by SCH 23390, whereas binding in the cerebellum was not reduced. Metabolite studies showed that about 80% of the radioactivity in the monkey plasma represented unchanged radioligand 30 min after injection. The rate of metabolism in monkey plasma in vivo was also determined for a series of structurally related 11C-labelled benzazepines, previously used as dopamine D1 receptor ligands for PET. Results indicate a significantly slower rate of metabolism for [11C]NNC 22-0215 than for any of the previously labelled benzazepines. Thus [11C]NNC 22-0215 has potential for imaging of selective binding to the dopamine D1 receptors in the human brain with high count rates at time of equilibrium

  3. Successful rechallenge with reduced dose of erlotinib in a patient with lung adenocarcinoma who developed erlotinib-associated leukocytoclastic vasculitis: A case report

    SU, BO-AN; SHEN, WAN-LIN; CHANG, SHENG-TSUNG; FENG, LI-YIA; Wu, Chia-Jung; Feng, Yin-Hsun

    2012-01-01

    The oral tyrosine kinase inhibitors of epidermal growth factor, erlotinib and gefitinib, are active in the treatment of non-small cell lung cancer (NSCLC). However, a number of skin manifestations have been found in patients receiving erlotinib therapy. Leukocytoclastic vasculitis is a rare side-effect of erlotinib therapy. However, whether or not erlotinib treatment should be continued when disseminated ulceration of leukocytoclastic vasculitis is encountered remains to be determined. In thi...

  4. (/sup 11/C)clorgyline and (/sup 11/C)-L-deprenyl and their use in measuring functional monoamine oxidase activity in the brain using positron emission tomography

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

    1986-04-17

    This invention involves a new strategy for imaging the activity of the enzyme monoamine oxidase in the living body by using /sup 11/C-labeled enzyme inhibitors which bind irreversibly to an enzyme as a result of catalysis. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography. 2 figs.

  5. Intrinsic caspase-8 activation mediates sensitization of erlotinib-resistant tumor cells to erlotinib/cell-cycle inhibitors combination treatment

    Orzáez, M; Guevara, T; Sancho, M; Pérez-Payá, E

    2012-01-01

    Inhibitors of the tyrosine kinase activity of epidermal growth factor receptor, as erlotinib, have an established role in treating several cancer types. However, resistance to erlotinib, particularly in breast cancer cell lines, and erlotinib treatment-associated disorders have also been described. Also, methods and combination therapies that could reverse resistance and ameliorate non-desirable effects represent a clinical challenge. Here, we show that the ATP non-competitive CDK2/cyclin A inhibitor NBI1 sensitizes erlotinib-resistant tumor cells to the combination treatment (co-treatment) for apoptosis-mediated cell death. Furthermore, in erlotinib-sensitive cells, the effective dose of erlotinib was lower in the presence of NBI1. The analysis in the breast cancer MDA-MB-468 erlotinib-resistant and in lung cancer A549 cell lines of the molecular mechanism underlying the apoptosis induced by co-treatment highlighted that the accumulation of DNA defects and depletion of cIAP and XIAP activates the ripoptosome that ultimately activates caspases-8 and -10 and apoptosis. This finding could have significant implications for future treatment strategies in clinical settings. PMID:23096116

  6. 11C-methylations using 11C-methyl iodide and tetrabutylammonium fluoride

    Carbon-11 methylation reactions on functional groups such as phenols and amides require a base when using 11C-methyl iodide. This study demonstrates that tetrabutylammonium fluoride (TBAF) can be used as a base to prepare 11C-radiopharmaceuticals efficiently and in high yield. We have applied this method to raclopride, methylphenidate, PK11195, dihydrotetrabenazine and MDL100907 and have compared the results with the Alumina/KF and hydroxide methods. Our results indicate that TBAF gives equivalent or higher radiochemical yields compared to the other bases even when using as little as 200 μg of precursor. In the case of PK11195 the TBAF method was the only one that provided a reasonable yield of product. (orig.)

  7. {sup 11}C-methylations using {sup 11}C-methyl iodide and tetrabutylammonium fluoride

    Adam, M.J.; Jivan, S.; Huser, J.M.; Lu, J. [TRIUMF Univ. of British Columbia, Vancouver (Canada)

    2000-07-01

    Carbon-11 methylation reactions on functional groups such as phenols and amides require a base when using {sup 11}C-methyl iodide. This study demonstrates that tetrabutylammonium fluoride (TBAF) can be used as a base to prepare {sup 11}C-radiopharmaceuticals efficiently and in high yield. We have applied this method to raclopride, methylphenidate, PK11195, dihydrotetrabenazine and MDL100907 and have compared the results with the Alumina/KF and hydroxide methods. Our results indicate that TBAF gives equivalent or higher radiochemical yields compared to the other bases even when using as little as 200 {mu}g of precursor. In the case of PK11195 the TBAF method was the only one that provided a reasonable yield of product. (orig.)

  8. In vivo binding of [11C]nemonapride to sigma receptors in the cortex and cerebellum

    Radiolabeled nemonapride (NEM, YM-09151-2) is widely used as a representative dopamine D2-like receptor ligand in pharmacological and neurological studies, and 11C-labeled analog ([11C]NEM) has been developed for positron emission tomography (PET) studies. The aim of this study was to evaluate whether [11C]NEM binds in vivo to sigma receptors. [11C]NEM and one of six dopamine D2-like receptor ligands or seven sigma receptor ligands were co-injected into mice, and the regional brain uptake of [11C]NEM was measured by a tissue dissection method. The striatal uptake of [11C]NEM was reduced by D2-like receptor ligands, NEM, haloperidol, (+)-butaclamol, raclopride, and sulpiride, but not by a D4 receptor ligand clozapine. In the cortex and cerebellum the uptake was also reduced by D2-like receptor ligands with affinity for sigma receptors, but not by raclopride. Although none of seven sigma receptor ligands, SA6298, N,N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]ethylamine hydrochloride (NE-100), (+)-pentazocine, R(-)-N-(3-phenyl-1-propyl)-1-phenyl-2-aminopropane hydrochloride ([-]-PPAP), (-)-pentazocine, R(+)-3-(3-hydroxyphenyl)-N-propylpiperidine hydrochloride ([+]-3-PPP), and (+)-N-allylnormetazocine hydrochloride ([+]-SKF 10047), blocked the striatal uptake, five of them with relatively higher affinity significantly reduced the [11C]NEM uptake by the cortex, and four of them reduced that by the cerebellum. We concluded that [11C]NEM binds in vivo not only to dopamine D2-like receptors in the striatum but also to sigma receptors in other regions such as cortex and cerebellum

  9. 11C-PET imaging reveals transport dynamics and sectorial plasticity of oak phloem after girdling

    De Schepper, Veerle; Bühler, Jonas; Thorpe, Michael; Roeb, Gerhard; Huber, Gregor; van Dusschoten, Dagmar; Jahnke, Siegfried; Steppe, Kathy

    2013-01-01

    Carbon transport processes in plants can be followed non-invasively by repeated application of the short-lived positron-emitting radioisotope 11C, a technique which has rarely been used with trees. Recently, positron emission tomography (PET) allowing 3D visualisation has been adapted for use with plants. To investigate the effects of stem girdling on the flow of assimilates, leaves on first order branches of two-year-old oak (Quercus robur L.) trees were labelled with 11C by supplying 11CO2-...

  10. Radiosynthesis of [11C]glyburide for in vivo imaging of BCRP function with PET

    Complete text of publication follows: Objectives: The human breast cancer resistance protein (BCRP/ABCG2) belongs to the ABC-transporter super-family in which P-gp (MDR1/ABCB1) is probably the most emblematic and best known member. BCRP, which was initially discovered in multidrug resistant breast cancer cell lines, is also highly expressed in numerous tissues e.g. the blood-brain barrier (BBB). BCRP confers upon these tissues resistance to chemotherapeutic agents but also transports drugs and xenobiotics thus participating to the ADME processes although the biochemical mechanisms remain largely unknown to date. The hypoglycaemic sulfonylurea glyburide (glibenclamide) has been described as a specific substrate of BCRP in vitro and in vivo. Its isotopic labelling with the positron emitter carbon-11 (20.4 min) would provide a valuable tool to study in vivo with PET the BCRP transport activity. Herein are reported the synthesis of desmethyl-glyburide (2), as precursor, as well as the preparation of [11C]glyburide ([11C]-1) using [11C]methyl triflate as radio-methylation agent. Methods: Chemistry: Desmethyl-glyburide (2), as precursor for [11C]labelling, was obtained in one chemical step by treating glyburide (1) with a 1 M solution of BBr3 (4 eq.) in dichloromethane at low temperature (-90 C to - 20 C). Radiochemistry: Carbon-11 labeling of glyburide (1) was performed using a TRACERLab FX-C Pro synthesizer (GEMS) and comprised (1) trapping at -10 C of [11C]MeOTf in acetone (0.3 mL) containing the precursor 2 (0.5-0.8 mg) and aq. 3N NaOH (5 μL); (2) heating at 110 C for 2 min; (3) dilution in 1.0 mL of the HPLC mobile phase and purification using semi-preparative reversed-phase HPLC (Waters SymmetryR C-18 - eluent: CH3CN / H2O / TFA: 45 / 55 / 0.1 (v:v:v) - flow rate: 5 mL/min - detection at 254 nm) and (4) SepPakR Plus C-18-based formulation for i.v. injection. The measurement of log P and log D7.4 was performed using the shaked flask method. Results: The desmethyl

  11. High molar activity of [11C]TCH346 via [11C]methyl triflate using the 'wet' [11C]CO2 reduction method

    [11C]TCH346, a compound acting on the glycolytic enzyme, glycerol-aldehyde-3-phosphate dehydrogenase, was produced under optimised conditions by methylation of the desmethyl compound with no-carrier added (n.c.a.) [11C]methyl triflate. An i.v. injectable solution of n.c.a. [11C]TCH346 containing 4040±1550 MBq (n=6) containing a molar activity between 40 and 5700 GBq/μmol and a radiochemical purity of >99% was obtained within 30 min (after EOB) by irradiation of nitrogen gas containing 0.5% oxygen with 16.5 MeV protons at 45 μA for 30 min. The alkylation reagent [11C]methyl triflate was prepared via on-line conversion of [11C]methyl iodide. For the formation of [11C]methyl iodide, [11C]carbon dioxide from the target chamber was reduced by a lithium aluminium hydride solution, and the methanol obtained on-line was converted using triphenylphosphine diiodide. The molar activity of [11C]TCH346 could be improved from 40 up to nearly 5700 GBq/μmol during the optimisation of the synthesis using the same stock solution of lithium aluminium hydride solution in tetrahydrofuran

  12. Comparison of autologous 111In-leukocytes, 18F-FDG, 11C-methionine, 11C-PK11195 and 68Ga-citrate for diagnostic nuclear imaging in a juvenile porcine haematogenous Staphylococcus aureus osteomyelitis model

    Nielsen, Ole L.; Afzelius, Pia; Bender, Dirk;

    The aim of this study was to compare 111In-labeled leukocyte single-photon emission computed tomography (SPECT) and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) to PET with tracers that potentially could improve detection of osteomyelitis. We chose 11C-methionine, 11C-PK11195...... and 68Ga-citrate and validated their diagnostic utility in a porcine haematogenous osteomyelitis model. Four juvenile 14-15 weeks old female pigs were scanned seven days after intra-arterial inoculation in the right femoral artery with a porcine strain of Staphylococcus aureus using a sequential scan...... protocol with 18F-FDG, 68Ga-citrate, 11C-methionine, 11C-PK11195, 99mTc-Nanocoll and 111In-labelled autologous leukocytes. This was followed by necropsy of the pigs and gross pathology, histopathology and microbial examination. The pigs developed a total of five osteomyelitis lesions, five lesions...

  13. Comparison of autologous 111In-leukocytes, 18F-FDG, 11C-methionine, 11C-PK11195 and 68Ga-citrate for diagnostic nuclear imaging in a juvenile porcine haematogenous Staphylococcus aureus osteomyelitis model

    Nielsen, Ole Lehberg; Afzelius, Pia; Bender, Dirk;

    2014-01-01

    The aim of this study was to compare 111In-labeled leukocyte single-photon emission computed tomography (SPECT) and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) to PET with tracers that potentially could improve detection of osteomyelitis. We chose 11C-methionine, 11C-PK11195...... and 68Ga-citrate and validated their diagnostic utility in a porcine haematogenous osteomyelitis model. Four juvenile 14-15 weeks old female pigs were scanned seven days after intra-arterial inoculation in the right femoral artery with a porcine strain of Staphylococcus aureus using a sequential scan...... protocol with 18F-FDG, 68Ga-citrate, 11C-methionine, 11C-PK11195, 99mTc-Nanocoll and 111In-labelled autologous leukocytes. This was followed by necropsy of the pigs and gross pathology, histopathology and microbial examination. The pigs developed a total of five osteomyelitis lesions, five lesions...

  14. Erlotinib-related keratopathy in a patient underwent laser in situ keratomileusis.

    Kau, Hui-Chuan; Tsai, Chieh-Chih

    2016-09-01

    Erlotinib is a tyrosine kinase inhibitor of the epidermal growth factor receptor. Since there is a wide expression of the epidermal growth factor receptors in the epithelial tissues of ocular surface and adnexa, ocular adverse reactions may happen during systemic administration of erlotinib. Previously reported ocular adverse reactions of erlotinib include trichomegaly, periorbital rash, ectropion, blepharitis, persistent corneal epithelial defect, corneal ulcer and perforation. We report the first case of erlotinib-related keratopathy in a patient who had received laser in situ keratomileusis. The patient presented a special picture of flap striae related to erlotinib. Improvement of keratopathy after cessation of erlotinib was demonstrated. PMID:26340340

  15. Radiopharmaceutical for differential diagnosis of tuberculoma: synthesis of 2-( sup 11 C)cyano-isonicotinic acid hydrazide

    Somawardhana, C.W.; Sajjad, M.; Lambrecht, R.M. (King Faisal Specialist Hospital and Research Centre, Riyadh (Saudi Arabia))

    1991-01-01

    The radiochemical synthesis of 2-({sup 11}C)cyano-isonicotinic acid hydrazide was accomplished. Carbon-11 labelled cyano-group was introduced at the 2-position of the pyridine ring of 1-methoxy-4-methoxycarbonyl pyridinium methyl sulfate via a Riessert-Kaufmann type reaction. The reaction was performed on a solid support (silica gel) to yield no-carrier-added methyl 2-({sup 11}C)cyano-isonicotinate in (32.4 +- 12%) (EOB) yield. This method is unique for the incorporation of ({sup 11}C)HCN to base sensitive substrates. The carbon-11 labelled methyl ester was treated with hydrazine hydrate to obtain 2-({sup 11}C)cyano-isonicotinic acid hydrazide. The final radiochemical yield was 10% (EOB) and the synthesis time was approximately 35 min. (author).

  16. Radiopharmaceutical for differential diagnosis of tuberculoma: synthesis of 2-[11C]cyano-isonicotinic acid hydrazide

    The radiochemical synthesis of 2-[11C]cyano-isonicotinic acid hydrazide was accomplished. Carbon-11 labelled cyano-group was introduced at the 2-position of the pyridine ring of 1-methoxy-4-methoxycarbonyl pyridinium methyl sulfate via a Riessert-Kaufmann type reaction. The reaction was performed on a solid support (silica gel) to yield no-carrier-added methyl 2-[11C]cyano-isonicotinate in (32.4 ± 12%) (EOB) yield. This method is unique for the incorporation of [11C]HCN to base sensitive substrates. The carbon-11 labelled methyl ester was treated with hydrazine hydrate to obtain 2-[11C]cyano-isonicotinic acid hydrazide. The final radiochemical yield was 10% (EOB) and the synthesis time was approximately 35 min. (author)

  17. Synthesis and 11C-Radiolabelling of 2-Carboranyl Benzothiazoles

    Kiran B. Gona

    2015-04-01

    Full Text Available Dicarba-closo-dodecaboranes, commonly known as carboranes, possess unique physico-chemical properties and can be used as hydrophobic moieties during the design of new drugs or radiotracers. In this work, we report the synthesis of two analogues of 2-(4-aminophenylbenzothiazole (a compound that was found to elicit pronounced inhibitory effects against certain breast cancer cell lines in vitro in which the phenyl ring has been substituted by a m-carborane cage. Two different synthetic strategies have been used. For the preparation of 1-(9-amino-1,7-dicarba-closo-dodecaboran-1-yl-benzo-thiazole, the benzothiazole group was first introduced on one of the cluster carbon atoms of m-carborane and the amine group was further attached in three steps. For the synthesis of 1-(9-amino-1,7-dicarba-closo-dodecaboran-1-yl-6-hydroxybenzothiazole, iodination was performed before introducing the benzothiazole group, and the amino group was subsequently introduced in six steps. Both compounds were radiolabelled with carbon-11 using [11C]CH3OTf as the labelling agent. Radiolabelling yields and radiochemical purities achieved should enable subsequent in vitro and in vivo investigations.

  18. Noninvasive measurement of liver regeneration with positron emission tomography and [2-11C]thymidine

    The feasibility of liver regeneration determination with [2-11C]thymidine and positron emission tomography was investigated in partially hepatectomized rats. Serial tomographic scans were performed over a 120-minute period after injection of [2-11C]thymidine together with tritium-labeled thymidine. Within 10 minutes after injection, positron emission tomography scans showed a twofold higher hepatic uptake in regenerating than in nonregenerating livers. Time-activity curves over the liver area indicated that the maximal uptake was followed by a faster decrease of 11C radioactivity in controls than in regenerating animals, so that total 11C activity remaining in the liver at 120 minutes accounted for 68% of maximum in regenerating and only 38% in controls. Tissue distribution studies performed at 120 minutes showed that total 11C radioactivity, expressed in percent injected dose per gram, was six times higher in regenerating livers than in controls (0.62% ± 0.07% in regenerating livers and 0.10% ± 0.03% in nonregenerating livers; P less than 0.001) and correlated with 3H radioactivity measured in the nuclear fraction (r = 0.92; P less than 0.001). When the hepatic uptake was expressed in percent of dose per organ, the difference between both groups increased (2.31% ± 0.23% in regenerating livers and 0.29% ± 0.02% in nonregenerating livers; P less than 0.001) because of higher weight of regenerating livers than of nonregenerating livers (3.83 ± 0.11 g in regenerating livers and 2.96 ± 0.16 g in nonregenerating livers; P less than 0.001). In other organs examined, no difference in 11C radioactivity was found between the two groups of rats. These results indicated the potential usefulness of [2-11C]thymidine and positron emission tomography for noninvasive measurement of liver regeneration

  19. Radiosynthesis of [11C]SB-705498, a selective transient receptor potential Vanilloid 1 (TRPV1) receptor antagonist

    Complete text of publication follows: Objectives: The transient receptor potential vanilloid 1 (TRPV1) receptor, previously known as the vanilloid receptor 1 (VR1), is a non-selective cation channel activated by a range of noxious stimuli and highly expressed in nociceptive fibres. TRPV1 receptor is involved in pain and sensitisation associated with tissue injury and inflammation and therefore represents a pharmacological target of choice for the development of novel therapeutic agents for the treatment of chronic pain, migraine and gastrointestinal disorders. Among a novel series of pyrrolidinyl ureas recently discovered by GSK, SB-705498 (1, namely 1-(2-bromophenyl)-3-[(R)-1-(5- trifluoromethylpyridin-2-yl)pyrrolidin-3-yl]urea) has been identified as a potent, selective and orally bioavailable TRPV1 antagonist and considered for positron emission tomography studies. SB-705498 (1) has therefore been isotopically labelled with the short-lived positron-emitter carbon-11 (t1/2: 20.38 min) at its urea site using [11C]phosgene in a one-pot two-step process, via the intermediate preparation of 2-bromophenyl [11C]isocyanate. Methods: Carbon-11-labeling of SB-705498 comprises: (A) Trapping of [11C]phosgene (radio-synthesized from cyclotron-produced [11C]methane via [11C]carbon tetrachloride using minor modifications of published processes) at room temperature for 1 to 2 minutes in 250 μL of acetonitrile containing 0.6 μmole of 2-bromoaniline (2) giving 2-bromophenyl [11C]isocyanate ([11C]-3), followed by (B) addition of an excess of chiral (R)-1-(5- trifluoromethylpyridin-2-yl)pyrrolidin-3-ylamine (4, 40 μmoles in 500 μL of acetonitrile) as the second amine and reaction at room temperature for an additional one minute giving the desired urea derivative ([11C]SB-705498 ([11C]-1)), (C) dilution of the crude reaction mixture with water (500 μL) containing 4% (v:v) of DEA, injection and purification on a semi-preparative Waters SymmetryR C18 HPLC column (eluent: H2O / CH

  20. Synthesis of [11C]N-methyl tetrahydroaminoacridine, a potent acetylcholine esterase inhibitor

    Tetrahydroaminoacridine (THA) is a potent central acting acetylcholine esterase (AChE) inhibitor which might be used as therapeutic agent in the treatment of Alzheimer's disease (AZD). In order to study the AChE activity in the brain by PET, the authors selected N-methyl THA, a potent AChE inhibitor, as a potential radioligand. In this paper, they report the synthesis and labelling of N-methyl THA with [11C]methyl iodide

  1. Correlative cluster analysis of [11C]CFT and [11C]raclopride images in positron emission tomography

    Aim: [11C]CFT and [11C]raclopride were used to evaluate pre-synaptic dopamine transporter availability and post-synaptic dopamine D2 receptor binding, respectively, by positron emission tomography (PET). A combined study with these tracers are useful for the differential diagnosis of Parkinson's disease. The aim of this work is development of a new method that can automatically analyze and display regional status of pre- and post-synaptic dopaminergic functions. Materials and Methods: Brain images with [11C]CFT and [11C]raclopride were obtained using a 3-dimensional (3D) PET camera (HEADTOME-V, Shimadzu Co., Ltd.) and were co-registered to the individual structural brain image by magnetic resonance imaging (MRI) using the method of automatic multimodality image registration. Correlation between the [11C]CFT uptake and the [11C]raclopride uptake was calculated pixel-by-pixel over the striatum. The pixels in the striatum were clustered into 3 or 4 segments by a hierarchical method, and the a clustered 3D image was reconstructed. Thus, the clustered image can be displaced in arbitrary angles. This method was applied to several patients with Parkinson's disease, that were early to moderate in stages, and showed symmetric or asymmetric PET images. Results: A clustered transaxial brain image of Parkinson's disease superimposed on MRI, contained a segment which showed high uptake of both [11C]CFT and [11C]raclopride and a segment which showed high uptake of [11C]raclopride but low uptake of [11C]CFT). The former and latter corresponded to caudate nucleus and putamen, respectively. The clustered 3D transaxial image effectively demonstrated the regional differences of pre- and post-synaptic dopaminergic functions. Conclusion: The present cluster analysis is clinically useful for objective evaluation of dopaminergic functions of patients with the parkinsonism by PET with [11C]CFT and [11C]raclopride

  2. Simple one-pot synthesis of cyclopropane (/sup 11/C) carbonyl chloride. Synthesis and biodistribution of (/sup 11/C) cyclorphan

    McPherson, D.W.; Hwang, D.-R.; Fowler, J.S.; Wolf, A.P.; MacGregor, R.M.; Arnett, C.D.

    1986-05-01

    A rapid, one-pot, synthesis of cyclopropane (/sup 11/C) carbonyl chloride was developed. This synthesis proceeded in 80% radio-chemical yield (EOB) in a synthesis time of 10 minutes. This acid chloride was then used to synthesize a model compound, (/sup 11/C)cyclorphan, by alkylation of norlevorphanol followed by reduction of the intermediate (/sup 11/C)amide in an overall synthesis time of 55 minutes and a radiochemical yield of 15% (EOB). The biodistribution of (/sup 11/C)cyclorphan in control and naloxone pretreated mice showed non-specific binding and rapid clearance from brain.

  3. Automated chemoenzymatic synthesis of no-carrier-added [carbonyl-{sup 11}C]propionyl L-carnitine for pharmacokinetic studies

    Davenport, R.J.; Pike, V.W.; Dowsett, K.; Turton, D.R.; Poole, K. [Hammersmith Hospital, London (United Kingdom). MRC Cyclotron Unit

    1997-07-30

    Propionyl-L-carnitine (PLC) is under development as a therapeutic for the treatment of peripheral artery disease, coronary heart disease and chronic heart failure. Three methods were examined for labelling PLC in its propionyl group with positron-emitting carbon-11 (t{sub 1/2} = 20.3 min), one chemical and two chemoenzymatic. The former was based on the preparation of [{sup 11}C]propionyl chloride as labelling agent via {sup 11}C-carboxylation of ethylmagnesium bromide with cyclotron-produced [{sup 11}C]carbon dioxide and subsequent chlorination. Reaction of carrier-added [{sup 11}C]propionyl chloride with L-carnitine in trifluoroacetic acid gave [{sup 11}C]PLC in 12% radiochemical yield (decay-corrected) from cyclotron-produced [{sup 11}C]carbon dioxide. However, the radiosynthesis was unsuccessful at the no-carrier added (NCA) level of specific radioactivity. [{sup 11}C]Propionate, as a radioactive precursor for chemoenzymatic routes, was prepared via carboxylation of ethylmagnesium bromide with [{sup 11}C]carbon dioxide and hydrolysis. NCA [{sup 11}C]PLC was prepared in 68 min in 14% radiochemical yield (decay-corrected) from [{sup 11}C]propionate via sequential conversions catalysed by acetate kinase, phosphotransacetylase and carnitine acetyltransferase. A superior chemoenzymatic synthesis of NCA [{sup 11}C]PLC was developed, based on the use of a novel supported Grignard reagent for the synthesis of [{sup 11}C]propionate and conversions by S-acetyl-CoA synthetase and carnitine acetyltransferase. This gave an overall radiochemical yield of 30-48% (decay-corrected). This synthesis was automated for radiation safety and provides pure NCA [{sup 11}C]PLC in high radioactivities ready for intravenous administration within 25 min from radionuclide production. The [{sup 11}C]PLC is suitable for pharmacokinetic studies in human subjects with PET and the elucidation of the fate of the propionyl group of PLC in vivo. (Author).

  4. Erlotinib, erlotinib-sulindac vs. placebo: a randomized, double-blind, placebo-controlled window trial in operable head and neck cancer

    Gross, Neil D.; Bauman, Julie E.; Gooding, William E.; Denq, William; Thomas, Sufi M.; Wang, Lin; Chiosea, Simion; Hood, Brian L.; Flint, Melanie S.; Sun, Mai; Conrads, Thomas P.; Ferris, Robert L.; Johnson, Jonas T.; Kim, Seungwon; Argiris, Athanassios; Wirth, Lori; Nikiforova, Marina N.; Siegfried, Jill M.; Grandis, Jennifer R.

    2014-01-01

    Purpose The epidermal growth factor receptor (EGFR) and cyclooxygenase-2 (COX-2) pathways are upregulated in head and neck squamous cell carcinoma (HNSCC). Preclinical models indicate synergistic anti-tumor activity from dual blockade. We conducted a randomized, double-blind, placebo-controlled window trial of erlotinib, an EGFR inhibitor; erlotinib plus sulindac, a non-selective COX inhibitor, vs. placebo. Experimental Design Patients with untreated, operable Stage II-IVb HNSCC were randomized 5:5:3 to erlotinib, erlotinib-sulindac, or placebo. Tumor specimens were collected before and after 7-14 days of treatment. The primary endpoint was change in Ki-67 proliferation index. We hypothesized an ordering effect in Ki-67 reduction: erlotinib-sulindac > erlotinib > placebo. We evaluated tissue microarrays by immunohistochemistry for pharmacodynamic modulation of EGFR and COX-2 signaling intermediates. Results From 2005-2009, 47 patients were randomized for the target 39 evaluable patients. Thirty-four tumor pairs were of sufficient quality to assess biomarker modulation. Ki-67 was significantly decreased by erlotinib or erlotinib-sulindac (omnibus comparison, two-sided Kruskal-Wallis, p=0.04). Wilcoxon pairwise contrasts confirmed greater Ki-67 effect in both erlotinib groups (erlotinib-sulindac vs. placebo p=0.043; erlobinib vs. placebo, p=0.027). There was a significant trend in ordering of Ki-67 reduction: erlotinib-sulindac > erlotinib > placebo (two-sided exact Jonckheere-Terpstra, p =0.0185). Low baseline pSrc correlated with greater Ki-67 reduction (R2 = .312, p = 0.024). Conclusions Brief treatment with erlotinib significantly decreased proliferation in HNSCC, with additive effect from sulindac. Efficacy studies of dual EGFR-COX inhibition are justified. pSrc is a potential resistance biomarker for anti-EGFR therapy, and warrants investigation as a molecular target. PMID:24727329

  5. A PET imaging agent with fast kinetics: synthesis and in vivo evaluation of the serotonin transporter ligand [{sup 11}C]2-[2-dimethylaminomethylphenylthio]-5-fluorophenylamine ([{sup 11}C]AFA)

    Huang Yiyun E-mail: hh285@columbia.edu; Narendran, Raj; Bae, Sung-A; Erritzoe, David; Guo Ningning; Zhu Zhihong; Hwang, D.-R.; Laruelle, Marc

    2004-08-01

    A new serotonin transporter (SERT) ligand, [{sup 11}C]2-[2-(dimethylaminomethylphenylthio)]-5-fluorophenylamine (10, [{sup 11}C]AFA), was synthesized and evaluated as a candidate PET radioligand in pharmacological and pharmacokinetic studies. As a PET radioligand, AFA (8) can be labeled with either C-11 or F-18. In vitro, AFA displayed high affinity for SERT (K{sub i} 1.46{+-}0.15 nM) and lower affinity for norepinephrine transporter (NET, K{sub i} 141.7{+-}47.4 nM) or dopamine transporter (DAT, K{sub i} >10,000 nM). [{sup 11}C]AFA (10) was prepared from its monomethylamino precursor 9 by reaction with high specific activity [{sup 11}C]methyl iodide. Radiochemical yield was 43{+-}20% based on [{sup 11}C]methyl iodide at end of bombardment (EOB, n = 10) and specific activity was 2,129 {+-} 1,369 Ci/mmol at end of synthesis (EOS, n = 10). Biodistribution studies in rats indicated that [{sup 11}C]AFA accumulated in brain regions known to contain high concentrations of SERT. Binding in SERT-rich brain regions was reduced significantly by pretreatment with either the cold compound 8 or with the selective serotonin reuptake inhibitor (SSRI) citalopram, but not by the selective norepinephrine reuptake inhibitor nisoxetine, thus underlining its in vivo binding selectivity and specificity for SERT. Imaging experiments in baboons demonstrated that the uptake pattern of [{sup 11}C]AFA in the baboon brain is consistent with the known distribution of SERT, with highest activity levels in the midbrain and thalamus, followed by striatum, hippocampus, and cortical regions. Activity levels in the baboon brain peaked at 15-40 min after radioligand injection, indicating a fast uptake kinetics for [{sup 11}C]AFA. Pretreatment of the baboon with citalopram (4 mg/kg) significantly reduced the specific binding of [{sup 11}C]AFA in all SERT-containing brain regions. Kinetic analysis revealed that the regional equilibrium specific to non-specific partition coefficients (V{sub 3}&apos

  6. A PET imaging agent with fast kinetics: synthesis and in vivo evaluation of the serotonin transporter ligand [11C]2-[2-dimethylaminomethylphenylthio)]-5-fluorophenylamine ([11C]AFA)

    A new serotonin transporter (SERT) ligand, [11C]2-[2-(dimethylaminomethylphenylthio)]-5-fluorophenylamine (10, [11C]AFA), was synthesized and evaluated as a candidate PET radioligand in pharmacological and pharmacokinetic studies. As a PET radioligand, AFA (8) can be labeled with either C-11 or F-18. In vitro, AFA displayed high affinity for SERT (Ki 1.46±0.15 nM) and lower affinity for norepinephrine transporter (NET, Ki 141.7±47.4 nM) or dopamine transporter (DAT, Ki >10,000 nM). [11C]AFA (10) was prepared from its monomethylamino precursor 9 by reaction with high specific activity [11C]methyl iodide. Radiochemical yield was 43±20% based on [11C]methyl iodide at end of bombardment (EOB, n = 10) and specific activity was 2,129 ± 1,369 Ci/mmol at end of synthesis (EOS, n = 10). Biodistribution studies in rats indicated that [11C]AFA accumulated in brain regions known to contain high concentrations of SERT. Binding in SERT-rich brain regions was reduced significantly by pretreatment with either the cold compound 8 or with the selective serotonin reuptake inhibitor (SSRI) citalopram, but not by the selective norepinephrine reuptake inhibitor nisoxetine, thus underlining its in vivo binding selectivity and specificity for SERT. Imaging experiments in baboons demonstrated that the uptake pattern of [11C]AFA in the baboon brain is consistent with the known distribution of SERT, with highest activity levels in the midbrain and thalamus, followed by striatum, hippocampus, and cortical regions. Activity levels in the baboon brain peaked at 15-40 min after radioligand injection, indicating a fast uptake kinetics for [11C]AFA. Pretreatment of the baboon with citalopram (4 mg/kg) significantly reduced the specific binding of [11C]AFA in all SERT-containing brain regions. Kinetic analysis revealed that the regional equilibrium specific to non-specific partition coefficients (V3'') of [11C]AFA are similar to those of [11C]McN5652, but lower than those of [11C]AFM or [11C

  7. Ex Vivo and In Vivo Evaluation of the Norepinephrine Transporter Ligand [11C]MRB for Brown Adipose Tissue Imaging

    Introduction: It has been suggested that brown adipose tissue (BAT) in humans may play a role in energy balance and obesity. We conducted ex vivo and in vivo evaluation using [11C]MRB, a highly selective NET (norepinephrine transporter) ligand for BAT imaging at room temperature, which is not achievable with [18F]FDG. Methods: PET images of male Sprague–Dawley rats with [18F]FDG and [11C]MRB were compared. Relative [18F]FDG or [11C]MRB retention at 20, 40 and 60 min post-injection was quantified on awake rats after exposing to cold (4 °C for 4 h) or remaining at room temperature. Rats pretreated with unlabeled MRB or nisoxetine 30 min before [11C]MRB injection were also assessed. The [11C]MRB metabolite profile in BAT was evaluated. Results: PET imaging demonstrated intense [11C]MRB uptake (SUV of 2.9 to 3.3) in the interscapular BAT of both room temperature and cold-exposed rats and this uptake was significantly diminished by pretreatment with unlabeled MRB; in contrast, [18F]FDG in BAT was only detected in rats treated with cold. Ex vivo results were concordant with the imaging findings; i.e. the uptake of [11C]MRB in BAT was 3 times higher than that of [18F]FDG at room temperature (P = 0.009), and the significant cold-stimulated uptake in BAT with [18F]FDG (10-fold, P = 0.001) was not observed with [11C]MRB (P = 0.082). HPLC analysis revealed 94%–99% of total radioactivity in BAT represented unchanged [11C]MRB. Conclusions: Our study demonstrates that BAT could be specifically labeled with [11C]MRB at room temperature and under cold conditions, supporting a NET-PET strategy for imaging BAT in humans under basal conditions.

  8. The Buecherer-Strecker synthesis of D- and L-(1-11C)tyrosine and the in vivo study of 0100L-(1-11C)tyrosine in human brain using positron emission tomography

    The synthesis of D- and L-(1-11C)tyrosine, starting with 11C-cyanide, is reported. DL-(1-11C)tyrosine was prepared by the Buecherer-Strecker reaction, from carrier added 11C-cyanide with an incorporation of 80% in 20 min. The isolation of the pure D- and L-amino acid isomers from the enantiomeric mixture was accomplished within 15 min by preparative HPLC using a chiral stationary phase and a phosphate buffer as the mobile phase. Typically, the total synthesis time was 50 min (including purification) from end of trapping of 11C-cyanide, with a radiochemical yield of D- and L-amino acid of 40%-60%. The D- and L-(1-11C)tyrosine were both obtained optically pure, with a carrier added specific activity of 0.3-0.5 Ci/mmol and a radiochemical purity better than 99%. The 11C labelled L-tyrosine was used in an in vivo study in the human brain using positron emission tomography (PET). (orig.)

  9. Automated production of [11C]acetate and [11C]palmitate using a modified GE Tracerlab FXC-Pro

    As researchers explore new applications for positron emission tomography radiopharmaceuticals, the demand for effective and readily available radiopharmaceuticals continues to increase. The syntheses of two such radiopharmaceuticals, [11C]acetate and [11C]palmitate, can be automated on the GE Tracerlab FXC-Pro by utilizing Grignard reactions. Radiochemical purities of the [11C]acetate and the [11C]palmitate products were high (>98% and >99.9%, respectively) with average non-corrected yields of 18% (n=3) and 10% (n=5), respectively. These data comprise the validation trials for site qualification of clinical production of both radiopharmaceuticals. -- Graphical abstract: Automated syntheses of [11C]acetate and [11C]palmitate using a modified GE Tracerlab FXC-Pro are reported. Radiochemical purities of the [11C]acetate and the [11C]palmitate products were high (>98% and >99.9%, respectively) with average non-corrected yields of 18% (n=3) and 10% (n=5), respectively.

  10. Evaluation of [11C]RTI-121 as a selective radioligand for PET studies of the dopamine transporter

    The cocaine analogue RTI-121 (3β-(4-iodophenyl)tropane-2β-carboxylic acid isopropyl ester), when labeled with carbon-11, was evaluated in rats as a potential PET ligand for the dopamine transporter. The compound gave in vivo striatum:cerebellum ratios that were similar to those obtained with the related ligand [11C]RTI-55 (2↔-(4-iodophenyl)tropane-2β-carboxylic acid methyl ester) but showed a much greater selectivity for the dopamine compared with the 5-HT uptake site. The results indicate that [11C]RTI-121 could be used in preference to [11C]RTI-55 in man. Experimentally, [11C]RTI-121 has potential in the quantification of dopamine terminal function in rat models of disease, using a combination of autoradiography, postmortem sampling, and in vivo tomography

  11. Automated radiosynthesis of [11C]morphine for clinical investigation

    To meet a multiple-dose clinical evaluation of the P-gp modulation of [11C]morphine delivery into the human brain, radiosynthesis of [11C]morphine was accomplished on an automated system by N-methylation of normorphine with [11C]CH3I. A methodology employing optimized solid phase extraction of the HPLC eluent was developed. Radiosynthesis took 45 min with a radiochemical yield ranging from 45% to 50% and specific activity ranging from 20 to 26 Ci/μmol (decay corrected to end-of-bombardment); radiochemical and chemical purities were >95% (n=28).

  12. Radiotracer synthesis from [11C]-iodomethane: a remarkably simple captive solvent method

    A new method of [11C]-methylation is described, which attains the goals of simplicity, high radiochemical yields, speed, versatility, and automation. A standard high performance liquid chromatography (HPLC) injection loop on a standard HPLC injection valve is loaded with a solution (80 μL) of precursor (0.3-1.0 mg) in dimethyl formamide (DMF) or dimethyl sulfoxide (DMSO) (+ base if required). At ambient temperature [11C]-iodomethane is passed through the loop for 3-4 min with >90% trapping of activity. After a further 1-5 min, the contents of the loop are quantitatively injected onto the HPLC column for purification. Radiochemical yields are equal to or superior to conventional solution methods in all cases, even though no heat is applied. [11C]-labeled radiotracers that have been prepared by this method for human or animal studies include Raclopride, N-methylspiperone, Ro 15-1788, FLB 457, RTI-32, Rolipram, SCH 23390, and SKF 82957. Since no vials, transfer lines, cooling, heating, or sealing valves are required, no transfer losses occur, yields are high, and cleanup is minimal, this 'loop method' is ideal for most radiopharmaceuticals prepared from [11C]-iodomethane

  13. Erlotinib promotes endoplasmic reticulum stress-mediated injury in the intestinal epithelium

    Fan, Lu; Hu, Lingna; Yang, Baofang; Fang, Xianying; Gao, Zhe; Li, Wanshuai; Sun, Yang; Shen, Yan; Wu, Xuefeng [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 22 Hankou Road, Nanjing 210093 (China); Shu, Yongqian [Department of Clinical Oncology, The First Affiliated Hospital of Nanjing Medical University, 140 Hanzhong Road, Nanjing 210029 (China); Gu, Yanhong, E-mail: guluer@163.com [Department of Clinical Oncology, The First Affiliated Hospital of Nanjing Medical University, 140 Hanzhong Road, Nanjing 210029 (China); Wu, Xudong, E-mail: xudongwu@nju.edu.cn [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 22 Hankou Road, Nanjing 210093 (China); Xu, Qiang, E-mail: molpharm@163.com [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)

    2014-07-01

    Erlotinib, a popular drug for treating non-small cell lung cancer (NSCLC), causes diarrhea in approximately 55% of patients receiving this drug. In the present study, we found that erlotinib induced barrier dysfunction in rat small intestine epithelial cells (IEC-6) by increasing epithelial permeability and down-regulating E-cadherin. The mRNA levels of various pro-inflammatory cytokines (Il-6, Il-25 and Il-17f) were increased after erlotinib treatment in IEC-6 cells. Erlotinib concentration- and time-dependently induced apoptosis and endoplasmic reticulum (ER) stress in both IEC-6 and human colon epithelial cells (CCD 841 CoN). Intestinal epithelial injury was also observed in male C57BL/6J mice administrated with erlotinib. Knockdown of C/EBP homologous protein (CHOP) with small interference RNA partially reversed erlotinib-induced apoptosis, production of IL-6 and down-regulation of E-cadherin in cultured intestinal epithelial cells. In conclusion, erlotinib caused ER stress-mediated injury in the intestinal epithelium, contributing to its side effects of diarrhea in patients. - Highlights: • Erlotinib destroyed barrier integrity both in vitro and in vivo. • Erlotinib induced inflammation both in vitro and in vivo. • Erlotinib induced apoptosis both in vitro and in vivo. • ER stress contributed to erlotinib-induced barrier dysfunction.

  14. Erlotinib promotes endoplasmic reticulum stress-mediated injury in the intestinal epithelium

    Erlotinib, a popular drug for treating non-small cell lung cancer (NSCLC), causes diarrhea in approximately 55% of patients receiving this drug. In the present study, we found that erlotinib induced barrier dysfunction in rat small intestine epithelial cells (IEC-6) by increasing epithelial permeability and down-regulating E-cadherin. The mRNA levels of various pro-inflammatory cytokines (Il-6, Il-25 and Il-17f) were increased after erlotinib treatment in IEC-6 cells. Erlotinib concentration- and time-dependently induced apoptosis and endoplasmic reticulum (ER) stress in both IEC-6 and human colon epithelial cells (CCD 841 CoN). Intestinal epithelial injury was also observed in male C57BL/6J mice administrated with erlotinib. Knockdown of C/EBP homologous protein (CHOP) with small interference RNA partially reversed erlotinib-induced apoptosis, production of IL-6 and down-regulation of E-cadherin in cultured intestinal epithelial cells. In conclusion, erlotinib caused ER stress-mediated injury in the intestinal epithelium, contributing to its side effects of diarrhea in patients. - Highlights: • Erlotinib destroyed barrier integrity both in vitro and in vivo. • Erlotinib induced inflammation both in vitro and in vivo. • Erlotinib induced apoptosis both in vitro and in vivo. • ER stress contributed to erlotinib-induced barrier dysfunction

  15. Synthesis and preclinical evaluation of the radiolabeled P-glycoprotein inhibitor [11C]MC113

    Objectives: With the aim to develop a PET tracer to visualize P-glycoprotein (Pgp) expression levels in different organs, the Pgp inhibitor MC113 was labeled with 11C and evaluated using small-animal PET. Methods: [11C]MC113 was synthesized by reaction of O-desmethyl MC113 with [11C]methyl triflate. Small-animal PET was performed with [11C]MC113 in FVB wild-type and Mdr1a/b(-/-) mice (n = 3 per group) and in a mouse model of high (EMT6Ar1.0) and low (EMT6) Pgp expressing tumor grafts (n = 5). In the tumor model, PET scans were performed before and after administration of the reference Pgp inhibitor tariquidar (15 mg/kg). Results: Brain uptake of [11C]MC113, expressed as area under the time-activity curve from time 0 to 60 min (AUC0-60), was moderately but not significantly increased in Mdr1a/b(-/-) compared with wild-type mice (mean ± SD AUC0-60, Mdr1a/b(-/-): 88 ± 7 min, wild-type: 62 ± 6 min, P = 0.100, Mann Whitney test). In the tumor model, AUC0-60 values were not significantly different between EMT6Ar1.0 and EMT6 tumors. Neither in brain nor in tumors was activity concentration significantly changed in response to tariquidar administration. Half-maximum effect concentrations (IC50) for inhibition of Pgp-mediated rhodamine 123 efflux from CCRFvcr1000 cells were 375 ± 60 nM for MC113 versus 8.5 ± 2.5 nM for tariquidar. Conclusion: [11C]MC113 showed higher brain uptake in mice than previously described Pgp PET tracers, suggesting that [11C]MC113 was only to a low extent effluxed by Pgp. However, [11C]MC113 was found unsuitable to visualize Pgp expression levels presumably due to insufficiently high Pgp binding affinity of MC113 in relation to Pgp densities in brain and tumors.

  16. A phase I dose-escalation and pharmacokinetic study of enzastaurin and erlotinib in patients with advanced solid tumors

    Padda, Sukhmani K.; Krupitskaya, Yelena; Chhatwani, Laveena; Fisher, George A; Colevas, Alexander D.; San Pedro-Salcedo, Melanie; Decker, Rodney; Latz, Jane E.; Wakelee, Heather A.

    2011-01-01

    Purpose Enzastaurin, an oral serine/threonine kinase inhibitor, targets the protein kinase C and AKT pathways with anti-tumor and anti-angiogenic effects. Erlotinib, an oral epidermal growth factor receptor (EGFR) inhibitor, has activity in solid tumors. Based on the promising combination of EGFR inhibitors and anti-angiogenic agents, this phase I trial was initiated. Methods This single-institution, open-label, non-randomized trial used a standard 3 + 3 dose-escalation model in patients with...

  17. Novel synthesis of [11C]GVG (Vigabatgrin) for pharmacokinetic studies of addiction treatment

    Ding, Y.S.; Studenov, A.R.; Zhang, Z.; Gerasimov, M.; Schiffer, W.; Dewey, S.L.; Telang, F.

    2001-06-10

    We report here a novel synthetic route to prepare the precursor and to efficiently label GVG with C-11. 5-Bromo-3-(carbobenzyloxy)amino-1-pentene was synthesized in five steps from homoserine lactone. This was used in a two step radiosynthesis, displacement with [{sup 11}C]cyanide followed by acid hydrolysis to afford [{sup 11}C]GVG with high radiochemical yields (> 35%, not optimized) and high specific activity (2-5 Ci/{micro}mol). The [{sup 11}C]cyanide trapping was achieved at {minus}5 C with a mixture of Kryptofix and K{sub 2}CO{sub 3} without using conventional aqueous trapping procedure [7]. At this temperature, the excess NH{sub 3} from the target that may interfere with the synthesis would not be trapped [8]. This procedure would be advantageous to any moisture sensitive radiosynthetic steps, as it was the case for our displacement reaction. When conventional aqueous trapping procedure was used, any trace amount of water left, even after prolonged heating, resulted in either no reaction or extremely low yields for the displacement reaction. The entire synthetic procedure should be extendible to the labeling of the pharmacologically active S- form of GVG when using S-homoserine lactone.

  18. Novel synthesis of [11C]GVG (Vigabatgrin) for pharmacokinetic studies of addiction treatment

    We report here a novel synthetic route to prepare the precursor and to efficiently label GVG with C-11. 5-Bromo-3-(carbobenzyloxy)amino-1-pentene was synthesized in five steps from homoserine lactone. This was used in a two step radiosynthesis, displacement with [11C]cyanide followed by acid hydrolysis to afford [11C]GVG with high radiochemical yields (> 35%, not optimized) and high specific activity (2-5 Ci/micromol). The [11C]cyanide trapping was achieved at minus5 C with a mixture of Kryptofix and K2CO3 without using conventional aqueous trapping procedure [7]. At this temperature, the excess NH3 from the target that may interfere with the synthesis would not be trapped [8]. This procedure would be advantageous to any moisture sensitive radiosynthetic steps, as it was the case for our displacement reaction. When conventional aqueous trapping procedure was used, any trace amount of water left, even after prolonged heating, resulted in either no reaction or extremely low yields for the displacement reaction. The entire synthetic procedure should be extendible to the labeling of the pharmacologically active S- form of GVG when using S-homoserine lactone

  19. The gene expression profile of CD11c

    W. Beumer (Wouter); J.M.C. Welzen-Coppens (Jojanneke); C.G. van Helden-Meeuwsen; S.M. Gibney (Sinead); H.A. Drexhage (Hemmo); M.A. Versnel (Marjan)

    2014-01-01

    textabstractTwo major dendritic cell (DC) subsets have been described in the pancreas of mice: The CD11c+CD8α- DCs (strong CD4+ T cell proliferation inducers) and the CD8α+CD103+ DCs (T cell apoptosis inducers). Here we analyzed the larger subset of CD11c

  20. Erlotinib-induced Rosacea-like Dermatitis.

    Rezaković, Saida; Paštar, Zrinjka; Bukvić Mokos, Zrinka; Pavliša, Gordana; Kovačević, Suzana

    2016-04-01

    Skin and skin adnexa toxicities are the most common side effects associated with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) and occur in most patients receiving this therapy. The majority of these cutaneous side effects are transient, reversible, and dose dependent. Although these symptoms are in general not severe, they significantly affect quality of life and can have a serious effect on treatment compliance as well as the treatment regimen. The most common early symptoms present as papulopustules on an erythematous base, usually localized in seborrheic areas. This clinical presentation is commonly described as "acneiform", although these adverse reactions have clinical presentations, such as rosacea-like and seborrheic-like dermatitis. In this context, we report a case of a 77-year-old man with a medical history of planocellular lung cancer with ipsilateral pulmonary metastasis and mediastinum infiltration who received erlotinib as a third-line therapy, presenting with centrofacial rosaceiform rash as a side effect associated with the use of EGFR-TKIs. The patient had a negative previous history of rosacea. Therefore, symptoms probably occurred as an adverse reaction due to the oncological therapy. Current terminology of early cutaneous adverse reactions caused by EGFR-TKIs refers to "acneiform" or "papulopustular" lesions, excluding less common side effects such as rosacea-like dermatitis so these symptoms might be overlooked and misdiagnosed. Thus, we would like to emphasize the importance of developing a more accurate classification of terms in order to provide early detection of all possible cutaneous side effects, including less common ones, providing specific and timely treatment, and allowing continuation of drug therapy. PMID:27149133

  1. 11C-PET imaging reveals transport dynamics and sectorial plasticity of oak phloem after girdling

    Veerle eDe Schepper

    2013-06-01

    Full Text Available Carbon transport processes in plants can be followed non-invasively by repeated application of the short-lived positron-emitting radioisotope 11C, a technique which has rarely been used with trees. Recently, positron emission tomography (PET allowing 3D visualisation has been adapted for use with plants. To investigate the effects of stem girdling on the flow of assimilates, leaves on first order branches of two-year-old oak (Quercus robur L. trees were labelled with 11C by supplying 11CO2-gas to a leaf cuvette. Magnetic resonance imaging gave an indication of the plant structure, while PET registered the tracer flow in a stem region downstream from the labelled branches. After repeated pulse labelling, phloem translocation was shown to be sectorial in the stem: leaf orthostichy determined the position of the phloem sieve tubes containing labelled 11C. The observed pathway remained unchanged for days. Tracer time-series derived from each pulse and analysed with a mechanistic model showed for two adjacent heights in the stem a similar velocity but different loss of recent assimilates. With either complete or partial girdling of bark within the monitored region, transport immediately stopped and then resumed in a new location in the stem cross-section, demonstrating the plasticity of sectoriality. One day after partial girdling, the loss of tracer along the interrupted transport pathway increased, while the velocity was enhanced in a non-girdled sector for several days. These findings suggest that lateral sugar transport was enhanced after wounding by a change in the lateral sugar transport path and the axial transport resumed with the development of new conductive tissue

  2. Palladium-mediated conversion of para-aminoarylboronic esters into para-aminoaryl- 11C-methanes

    Andersen, Valdemar Lykke; Herth, Matthias Manfred; Lehel, Szabolcs;

    2013-01-01

    Cross-couplings are an alternative to conventional 11C-methylations which are generally employed in PET tracer synthesis. Therefore, we set out to develop a general procedure for the synthesis of para-11CH3 labeled aromatic amines from the corresponding para-aminoarylboronic esters in the presenc...

  3. Erlotinib: CP 358774, NSC 718781, OSI 774, R 1415.

    2003-01-01

    Erlotinib [Tarceva, R 1415, CP 358774, OSI 774, NSC 718781] is a small molecular, once-a-day, orally active inhibitor of the epidermal growth factor receptor tyrosine kinase. This profile has been selected from R&D Insight, a pharmaceutical intelligence database produced by Adis International Ltd. It is one of a class of anticancer drugs that target the underlying molecular mechanism involving oncogenes and tumour suppressor genes, which play critical roles in the conversion of normal cells into a cancerous state. Erlotinib is undergoing clinical development as an oral tablet by an alliance between OSI Pharmaceuticals, Genentech and Roche. OSI Pharmaceuticals, Genentech and Roche have entered an agreement for the global development and commercialisation of erlotinib. Under the terms of the agreement, Genentech and OSI will share costs and profit-taking for commercialising the product in the US. The overall costs of the development programme will be shared equally between the three companies. OSI will keep certain co-promotion rights in the US and Genentech will be responsible for commercialising the drug in the US should the FDA approve it. Roche will take the responsibility for obtaining regulatory approval and commercialisation in territories outside the US and pay royalties to OSI on net sales of the product in these markets. Initially, the alliance partners intend to pursue development of erlotinib in all the major tumour markets, particularly for non-small cell lung cancer (NSCLC) in which the group will focus on front-line combination approaches. Pfizer and OSI Pharmaceuticals in the US were developing erlotinib as a treatment for solid tumours. However, in June 2000, Pfizer merged with Warner-Lambert. The resulting company retained the Pfizer name, but in order to meet Federal Trade Commission requirements for the merger Pfizer granted all developmental and marketing rights for erlotinib to OSI Pharmaceuticals. This divestiture of the erlotinib portfolio, in

  4. Human whole-body biodistribution and dosimetry of a new PET tracer, [11C]ketoprofen methyl ester, for imagings of neuroinflammation

    Introduction: Neuroinflammatory processes play an important role in the pathogenesis of Alzheimer's disease and other brain disorders, and nonsteroidal anti-inflammatory drugs (NSAIDs) are considered therapeutic candidates. As a biomarker of neuroinflammatory processes, 11C-labeled ketoprofen methyl ester ([11C]KTP-Me) was designed to allow cerebral penetration of ketoprofen (KTP), an active form of a selective cyclooxygenase-1 inhibitor that acts as an NSAID. Rat neuroinflammation models indicate that [11C]KTP-Me enters the brain and is retained in inflammatory lesions, accumulating in activated microglia. [11C]KTP-Me is washed out from normal tissues, leading to the present first-in-human exploratory study. Methods: [11C]KTP-Me was synthesized by rapid C-[11C]methylation of [11C]CH3I and the corresponding arylacetate precursor, purified with high-performance liquid chromatography, and prepared as an injectable solution including PEG400, providing radiochemical purity of > 99% and specific activity of > 25 GBq/μmol at injection. Six young healthy male humans were injected with [11C]KTP-Me and scanned with PET camera to determine the early-phase brain time course followed by three whole-body scans starting 8, 20, and 40 min post-injection, together with sequential blood sampling and labeled metabolite analysis. Results: No adverse effects were observed during PET scanning after [11C]KTP-Me injection. [11C]KTP-Me was rapidly metabolized to 11C-labeled ketoprofen ([11C]KTP) within 2–3 min and was gradually cleared from blood. The radioactivity entered the brain with an average peak cortical SUV of 1.5 at 2 min. The cortical activity was gradually washed out. Whole-body images indicated that the urinary bladder was the major excretory pathway. The organ with the highest radiation dose was the urinary bladder (average dose of 41μGy/MBq, respectively). The mean effective dose was 4.7 μSv/MBq, which was comparable to other 11C-labeled radiopharmaceuticals

  5. Effect of tracer metabolism on PET measurement of [[sup 11]C]pyrilamine binding to histamine H[sub 1] receptors

    Kim, Sang Eun (Sungkyunkwan Univ., Seoul (Korea, Republic of). School of Medicine); Szabo, Z.; Seki, Chie; Ravert, H.T.; Scheffel, U.; Dannals, R.F.; Wagner, H.N. Jr.

    1999-04-01

    The present study was carried out to investigate the time course of [[sup 11]C]pyrilamine metabolism and the degree of entry of metabolites into the brain. PET studies were performed in seven healthy volunteers and arterial plasma concentrations of [[sup 11]C]pyrilamine and its labeled metabolites were determined. After intravenous injection, [[sup 11]C]pyrilamine metabolized gradually in the human body, with less than 10% of plasma activity being original radioligand at 60 min. Tracer metabolism markedly affected the input function and the calculated impulse response function of the brain. Rat experiments demonstrated that although metabolites of [[sup 11]C]pyrilamine might enter the brain, they were not retained for prolonged periods of time. At 30-90 min after injection of [[sup 11]C]pyrilamine, less than 1% of the radioactivity in the brain was originating from metabolites of [[sup 11]C]pyrilamine. Based on the rat data, the contribution of [sup 11]C-labeled metabolites to total [[sup 11]C]pyrilamine radioactivity in the human brain was estimated and found to be negligible. These results suggest that the metabolites of [[sup 11]C]pyrilamine do not accumulate within the cerebral extravascular space and that there is minimal metabolism of [[sup 11]C]pyrilamine by brain tissue itself. Therefore, [[sup 11]C]pyrilamine metabolites can be neglected in kinetic analysis, using either a compartmental or a noncompartmental model, of the [[sup 11]C]pyrilamine binding to histamine H[sub 1] receptors. (author)

  6. Effect of tracer metabolism on PET measurement of [{sup 11}C]pyrilamine binding to histamine H{sub 1} receptors

    Kim, Sang Eun [Sungkyunkwan Univ., Seoul (Korea, Republic of). School of Medicine; Szabo, Z.; Seki, Chie; Ravert, H.T.; Scheffel, U.; Dannals, R.F.; Wagner, H.N. Jr.

    1999-04-01

    The present study was carried out to investigate the time course of [{sup 11}C]pyrilamine metabolism and the degree of entry of metabolites into the brain. PET studies were performed in seven healthy volunteers and arterial plasma concentrations of [{sup 11}C]pyrilamine and its labeled metabolites were determined. After intravenous injection, [{sup 11}C]pyrilamine metabolized gradually in the human body, with less than 10% of plasma activity being original radioligand at 60 min. Tracer metabolism markedly affected the input function and the calculated impulse response function of the brain. Rat experiments demonstrated that although metabolites of [{sup 11}C]pyrilamine might enter the brain, they were not retained for prolonged periods of time. At 30-90 min after injection of [{sup 11}C]pyrilamine, less than 1% of the radioactivity in the brain was originating from metabolites of [{sup 11}C]pyrilamine. Based on the rat data, the contribution of {sup 11}C-labeled metabolites to total [{sup 11}C]pyrilamine radioactivity in the human brain was estimated and found to be negligible. These results suggest that the metabolites of [{sup 11}C]pyrilamine do not accumulate within the cerebral extravascular space and that there is minimal metabolism of [{sup 11}C]pyrilamine by brain tissue itself. Therefore, [{sup 11}C]pyrilamine metabolites can be neglected in kinetic analysis, using either a compartmental or a noncompartmental model, of the [{sup 11}C]pyrilamine binding to histamine H{sub 1} receptors. (author)

  7. On the chemistry of 11C recoil atoms in alkyl halogenides and hydrogen halides

    The gas phase reactions of 11C recoil atoms which were produced by the nuclear reaction 14N(p,α)11C, were investigated in this present work in mixtures of N2 with CH3Cl, CH3Br and CH3I as well as with HCl, HBr and HI. The radiochemical yields of the gaseous reaction products were determined by radiogaschromatography. By using different columns, the carrier-free compounds produced could be clearly identified. Higher boiling products which occured in the present systems as wall activities were detected in some cases by means of high-pressure liquid chromotography. The formation of the products is discussed in the light of known recoil chemical reactions (abstraction, insertion) where attention is paid to the influence of O2 inhibitors and radiation dose effects. The quite considerable radiochemical yield of 11C-labelled methyl iodide in the N2/HI system enables the development of an on-line system for the recoil synthesis of larger amounts of activity of this important methylating agent for fast 11C labelling. A system was thus developed consisting of a gas dosing unit, target, gas purification system, and collector apparatus which enables the optimization of the product conditions by varying different parameters (proton energy, beam intensity, gas composition) and which enables the production of 11CH3-I activity quantities upto 90 mCi within a radiation and collecting time of 40 minutes at beam intensities of 20 μa and a proton input energy of 16 to 20 MeV. Specific activities of approx. 300 mCi/μmol are achieved. (orig.)

  8. Effects of the EGFR Inhibitor Erlotinib on Magnesium Handling

    Dimke, Henrik Anthony; van der Wijst, Jenny; Alexander, Todd R;

    2010-01-01

    A mutation in pro-EGF causes isolated hypomagnesemia, and monoclonal antibodies targeting the extracellular domain of the EGF receptor (EGFR) affect epithelial Mg(2+) transport. The effect of the EGFR tyrosine kinase inhibitor erlotinib on Mg(2+) homeostasis, however, remains unknown. Here, we in...

  9. An automated SPE-based high-yield synthesis of [11C]acetate and [11C]palmitate: no liquid–liquid extraction, solvent evaporation or distillation required

    Introduction: An automated method is described for the rapid and high-yield synthesis of two of the most commonly used radioactive fatty acids: [11C]acetate and [11C]palmitate. Methods: Reaction of [11C]CO2 with the respective Grignard reagents in diethyl ether solution proceeded for 2 min at 40°C. Quenching of the reaction and liberation of nonreacted [11C]CO2 occurred upon addition of a fourfold molar excess of aqueous 0.1 M HCl (acetate) or nonaqueous HCl/Et2O (palmitate). Labeled products were then purified by adsorption to an Alumina-N Sep-Pak Plus cartridge and eluted with either aqueous NaH2PO4 solution (acetate) or 100% ethanol (palmitate). Results: High-performance liquid chromatography analysis confirmed that the radiochemical purity of each product was >98%, and decay-corrected radiochemical yields averaged 33% for [11C]palmitate and 40% for [11C]acetate. Conclusion: The method requires no liquid–liquid extraction, solvent evaporation or distillation capabilities and can be readily adapted to existing radiosynthesis modules.

  10. Reliable set-up for in-loop 11C-carboxylations using Grignard reactions for the preparation of [carbonyl-11C]WAY-100635 and [11C]-(+)-PHNO

    Aim of this work was the implementation of a generalized in-loop synthesis for 11C-carboxylations and subsequent 11C-acylations on the TRACERlab FxC Pro platform. The set-up was tested using [carbonyl-11C]WAY-100635 and, for the first time, [11C]-(+)-PHNO. Its general applicability could be demonstrated and both [carbonyl-11C]WAY-100635 and [11C]-(+)-PHNO were prepared with high reliability and satisfying outcome. - Highlights: • Generalized method for in-loop 11C-carboxylations implemented. • Grignard reactions successfully tested. • First in-loop procedure for [11C]-(+)PHNO established. • Satisfactory synthesis outcome for both [carbonyl-11C]WAY-100635 and [11C]-(+)PHNO. • No distillation for purification of intermediate required

  11. Alternative methods of making [11C]amides: Application to the preparation of 5-HT1A receptor radioligands

    Many ligands for brain 5-HT1A receptors contain an amide group that is subject to hydrolysis in vivo. In the development of radioligands for use with positron emission tomography (PET), labelling in the carbonyl function of an amide group may be advantageous for avoiding radioactive metabolites that would readily enter the brain to confound PET receptor measurements. Several methods of labelling secondary and tertiary amides in their carbonyl functions with 11C (T1/2 = 20.4 min) have been developed over the past two decades or so. These methods include reaction of a [carbonyl-11C]acid chloride, [carboxyl-11C]magnesium halide carboxylate or [carboxyl-11C]acid with an amine or reaction of [11C]carbon monoxide with an amine plus an aryl halide, alkyl halide or aryl triflate. Some of these processes are successfully promoted with microwaves, palladium complexes, light or thermally initiated radicals. These methods are surveyed here and especially exemplified from research on the development of 5-HT1A receptor radioligands for brain imaging applications with PET. (author)

  12. Synthesis of [1-11C]D-glucosamine and evaluation of its in vivo distribution in rat with PET

    D-Glucosamine is a structural unit of many biologically interesting macromolecules. To investigate the feasibility of using labelled D-glucosamine as a tracer for anabolic processes, a two-step synthetic procedure for specifically labelling D-glucosamine in position 1 with carbon-11 was developed. [11C]Cyanide was reacted with an imine precursor, N-benzyl-D-arabinosylamine, to generate the [1-11C]α-amino nitrile. Reduction to [1-11C]D-glucosamine was accomplished by catalytic hydrogenation using PdC12 and the N-benzyl group was simultaneously removed. The total synthesis time from end-of-trapping of [11C]cyanide was 40-45 min and the decay-corrected radiochemical yield was 5-10% after HPLC isolation. The biodistribution of [1-11C]D-glucosamine in rat following i.v. bolus injection was investigated using positron emission tomography and showed that the availability of this substance for CNS anabolism is low with the primary limitation being the intact blood-brain barrier. (Author)

  13. Improved synthesis of 1-[11C]D-glucose

    An improved synthesis of 1-[11C]D-glucose is described. The major improvement is achieved when a 0.033 M borate buffer at pH 8.1 is used to effect the condensation of D-arabinose with NH411CN. Subsequent reduction of the 1-[11C]D-aldonitriles gives the epimeric sugars 1-[11C]D-glucose and 1-[11C]D-mannose in a ratio of 1.8 ± 0.57 as the major products. The decay corrected radiochemical yield is about 30% for the mixture of sugars. The overall synthesis, starting with the production of NH411CN, is conducted in a dedicated remote system. The remote gantry was easy to build with commercially available valves and glassware, and has been practically trouble-free after more than 2 years of use. Improved purification and quality control of the final product uses ion chromatography and a more efficient resin, and is also described. A preliminary PET study on a macaque has been conducted using 1-[11C]D-glucose obtained with this new improved synthesis. (author)

  14. Preparation and biodistribution in mice of [11C]carfentanil

    A potent μ-opioid agonist, [11C]carfentanil, was prepared by the methylation of carfentanil carboxylic acid with [11C]methyl iodide in order to study brain μ-opioid receptors by positron emission tomography. Synthesis (including purification) was completed within 25 min and the radiochemical yield was approximately 40%. The radiochemical purity of the product was more than 99% and its specific activity was 3.7-7.4 GBq/μmol. Biodistribution studies performed in mice after intravenous injection showed a high brain uptake and rapid blood clearance, so a high brain/blood ratio of 1.5-1.8 was found from 5 to 30 min. Regional cerebral distribution studies in the mouse showed a significantly higher uptake of [11C]carfentanil by the thalamus and striatum than by the cerebellum, with the radioactivity in the striatum disappearing more rapidly than that in the thalamus. Treatment with naloxone significantly reduced the uptake of [11C]carfentanil by the thalamus and striatum. These results indicate that [11C]carfentanil binds specifically to brain μ-opioid receptors. (author)

  15. 18F fluoroethylations: different strategies for the rapid translation of 11C-methylated radiotracers

    Introduction: The translation of 11C-labeled compounds into their respective 18F-labeled derivatives is an important tool in the rapid development of positron emission tomography (PET) tracers. Thus, our aim was the development of a general method for the preparation of 18F-fluoroethylated compounds that (a) is applicable to a variety of precursors, (b) can be performed in a fully automated commercially available synthesizer and (c) enables this rapid translation of 11C-methylated tracers into their 18F-fluoroethylated analogs sharing the same precursor molecules. Methods: Ten methods for the preparation and purification of different 18F-fluoroethylating agents were compared. Subsequently, five 18F-labeled PET tracers were synthesized under fully automated conditions. Results: Radiochemical yields ranged from 34.4% to 60.8%, and time consumption ranged from 20 to 55 min for all methods. Use of 1-bromo-2-[18F]fluoroethane and distillation evinced as the method of choice. Conclusions: We were able to develop a general method for the preparation of a variety of 18F-fluoroethylated molecules. The provided tool is solely based on commercially available resources and has the potential to simplify and accelerate innovative PET tracer development in the future

  16. Quantification of the novel N-methyl-d-aspartate receptor ligand [11C]GMOM in man.

    van der Doef, Thalia F; Golla, Sandeep Sv; Klein, Pieter J; Oropeza-Seguias, Gisela M; Schuit, Robert C; Metaxas, Athanasios; Jobse, Ellen; Schwarte, Lothar A; Windhorst, Albert D; Lammertsma, Adriaan A; van Berckel, Bart Nm; Boellaard, Ronald

    2016-06-01

    [(11)C]GMOM (carbon-11 labeled N-(2-chloro-5-thiomethylphenyl)-N'-(3-[(11)C]methoxy-phenyl)-N'-methylguanidine) is a PET ligand that binds to the N-methyl-d-aspartate receptor with high specificity and affinity. The purpose of this first in human study was to evaluate kinetics of [(11)C]GMOM in the healthy human brain and to identify the optimal pharmacokinetic model for quantifying these kinetics, both before and after a pharmacological dose of S-ketamine. Dynamic 90 min [(11)C]GMOM PET scans were obtained from 10 subjects. In six of the 10 subjects, a second PET scan was performed following an S-ketamine challenge. Metabolite corrected plasma input functions were obtained for all scans. Regional time activity curves were fitted to various single- and two-tissue compartment models. Best fits were obtained using a two-tissue irreversible model with blood volume parameter. The highest net influx rate (Ki) of [(11)C]GMOM was observed in regions with high N-methyl-d-aspartate receptor density, such as hippocampus and thalamus. A significant reduction in the Ki was observed for the entire brain after administration of ketamine, suggesting specific binding to the N-methyl-d-aspartate receptors. This initial study suggests that the [(11)C]GMOM could be used for quantification of N-methyl-d-aspartate receptors. PMID:26661185

  17. The synthesis of [O-methyl-{sup 11}C]venlafaxine: a non-classical, fast-acting antidepressant

    Gee, A.D.; Gjedde, A. [Aarhus Univ. Hospital, PET Center, Aarhus (Denmark); Smith, D.F. [Aarhus Univ. Psychiatric Hospital, Inst. for Biological Psychiatry, Risskov (Denmark)

    1997-01-01

    As part of our program to develop PET tracers for the 5-HT reuptake site, venlafaxine, a non-classical, fast-acting antidepressant, was selected as a candidate for labelling with {sup 11}C for in vivo evaluation. [O-methyl-{sup 11}C]venlafaxine was produced by the alkylation of O-desmethyl venlafaxine with [{sup 11}C]methyl iodide followed by HPLC purification and formulation. Radiochemically pure [O-methyl-{sup 11}C]venlafaxine was obtained in a 30 {+-} 5% decay corrected radiochemical yield and a specific activity > 50 GBq/{mu}mol(1.4 Ci/{mu}mol) at the end of synthesis. For a typical production starting with 46 GBq (1.3 Ci) [{sup 11}C]CO{sub 2}, 5.2 GBq (140 mCi) [O-methyl-{sup 11}C]venlafaxine was obtained as a sterile, formulated solution in a synthesis time of 30 min (counted from EOB). (Author).

  18. Optimization and Biodistribution of [(11)C]-TKF, An Analog of Tau Protein Imaging Agent [(18)F]-THK523.

    Kong, Yanyan; Guan, Yihui; Hua, Fengchun; Zhang, Zhengwei; Lu, Xiuhong; Zhu, Tengfang; Zhao, Bizeng; Zhu, Jianhua; Li, Cong; Chen, Jian

    2016-01-01

    The quantification of neurofibrillary tangles (NFTs) using specific PET tracers can facilitate the diagnosis of Alzheimer's disease (AD) and allow monitoring of disease progression and treatment efficacy. [(18)F]-THK523 has shown high affinity and selectivity for tau pathology. However, its high retention in white matter, which makes simple visual inspection difficult, may limit its use in research or clinical settings. In this paper, we optimized the automated radiosynthesis of [(11)C]-TKF and evaluated its biodistribution and toxicity in C57 mice. [(11)C]-TKF can be made by reaction precursor with [(11)C]MeOTf or (11)CH₃I, but [(11)C]MeOTf will give us higher labeling yields and specific activity. [(11)C]-TKF presented better brain uptake in normal mouse than [(18)F]-THK523 (3.23% ± 1.25% ID·g(-1) vs. 2.62% ± 0.39% ID·g(-1) at 2 min post-injection). The acute toxicity studies of [(11)C]-TKF were unremarkable. PMID:27527142

  19. Synthesis and in vivo distribution in the rat of a dopamine agonist: N-([11C]methyl)norapomorphine

    A method for the rapid production and purification of 10,11-dihydroxy-N-([11Cmethyl)norapomorphine ([11C]APO), a dopamine agonist (DA), is described. The potency of this ligand for studying the D2-receptors was examined. The label was introduced by N-methylation of norapomorphine hydrobromide with no-carrier-added (n.c.a.) [11C]CH3I, produced from cyclotron-produced [11C]carbon dioxide. In 60 min (EOB) a radiochemical yield of 15% (corrected for decay) was achieved, based on [11C]CH3I. The specific activity ranged from 5 to 11 GBq/μmol. The distribution, after intravenous injection, was studied in rats. The radioactivity level in the striatum was higher than in the cerebellum and frontal cortex and was decreased after D2-blockade. The highest uptake ratio (1.47) was found at 30 min after injection. Dopamine depletion with reserpine did increase the striatum/cerebellum ratio at a low dosage of [11C]APO (10 nmol/kg). High uptakes of [11C]apomorphine were found in the lungs, liver and kidneys. (author)

  20. [11C]-MeJDTic: a novel radioligand for κ-opioid receptor positron emission tomography imaging

    Introduction: Radiopharmaceuticals that can bind selectively the κ-opioid receptor may present opportunities for staging clinical brain disorders and evaluating the efficiency of new therapies related to stroke, neurodegenerative diseases or opiate addiction. The N-methylated derivative of JDTic (named MeJDTic), which has been recently described as a potent and selective antagonist of κ-opioid receptor in vitro, was labeled with carbon-11 and evaluated for in vivo imaging the κ-opioid receptor in mice. Methods: [11C]-MeJDTic was prepared by methylation of JDTic with [11C]-methyl triflate. The binding of [11C]-MeJDTic to κ-opioid receptor was investigated ex vivo by biodistribution and competition studies using nonfasted male CD1 mice. Results: [11C]-MeJDTic exhibited a high and rapid distribution in peripheral organs. The uptake was maximal in lung where the κ receptor is largely expressed. [11C]-MeJDTic rapidly crossed the blood-brain barrier and accumulated in the brain regions of interest (hypothalamus). The parent ligand remained the major radioactive compound in brain during the experiment. Chase studies with U50,488 (a κ referring agonist), morphine (a μ agonist) and naltrindole (a δ antagonist) demonstrated that this uptake was the result of specific binding to the κ-opioid receptor. Conclusion: These findings suggested that [11C]-MeJDTic appeared to be a promising selective 'lead' radioligand for κ-opioid receptor PET imaging

  1. Low background and high contrast PET imaging of amyloid-β with [11C]AZD2995 and [11C]AZD2184 in Alzheimer’s disease patients

    Forsberg, Anton; Juréus, Anders; Cselényi, Zsolt; Eriksdotter, Maria; Freund-Levi, Yvonne; Jeppsson, Fredrik; Swahn, Britt-Marie; Sandell, Johan; Julin, Per; Schou, Magnus; Andersson, Jan; Johnström, Peter; Varnäs, Katarina; Halldin, Christer; Farde, Lars

    2013-01-01

    Purpose The aim of this study was to evaluate AZD2995 side by side with AZD2184 as novel PET radioligands for imaging of amyloid-β in Alzheimer’s disease (AD). Methods In vitro binding of tritium-labelled AZD2995 and AZD2184 was studied and compared with that of the established amyloid-β PET radioligand PIB. Subsequently, a first-in-human in vivo PET study was performed using [11C]AZD2995 and [11C]AZD2184 in three healthy control subjects and seven AD patients. Results AZD2995, AZD2184 and PI...

  2. Preclinical PET Neuroimaging of [11C]Bexarotene.

    Rotstein, Benjamin H; Placzek, Michael S; Krishnan, Hema S; Pekošak, Aleksandra; Collier, Thomas Lee; Wang, Changning; Liang, Steven H; Burstein, Ethan S; Hooker, Jacob M; Vasdev, Neil

    2016-01-01

    Activation of retinoid X receptors (RXRs) has been proposed as a therapeutic mechanism for the treatment of neurodegeneration, including Alzheimer's and Parkinson's diseases. We previously reported radiolabeling of a Food and Drug Administration-approved RXR agonist, bexarotene, by copper-mediated [(11)C]CO2 fixation and preliminary positron emission tomography (PET) neuroimaging that demonstrated brain permeability in nonhuman primate with regional binding distribution consistent with RXRs. In this study, the brain uptake and saturability of [(11)C]bexarotene were studied in rats and nonhuman primates by PET imaging under baseline and greater target occupancy conditions. [(11)C]Bexarotene displays a high proportion of nonsaturable uptake in the brain and is unsuitable for RXR occupancy measurements in the central nervous system. PMID:27553293

  3. In vivo binding of [{sup 11}C]nemonapride to sigma receptors in the cortex and cerebellum

    Ishiwata, Kiichi E-mail: ishiwata@pet.tmig.or.jp; Senda, Michio

    1999-08-01

    Radiolabeled nemonapride (NEM, YM-09151-2) is widely used as a representative dopamine D{sub 2}-like receptor ligand in pharmacological and neurological studies, and {sup 11}C-labeled analog ([{sup 11}C]NEM) has been developed for positron emission tomography (PET) studies. The aim of this study was to evaluate whether [{sup 11}C]NEM binds in vivo to sigma receptors. [{sup 11}C]NEM and one of six dopamine D{sub 2}-like receptor ligands or seven sigma receptor ligands were co-injected into mice, and the regional brain uptake of [{sup 11}C]NEM was measured by a tissue dissection method. The striatal uptake of [{sup 11}C]NEM was reduced by D{sub 2}-like receptor ligands, NEM, haloperidol, (+)-butaclamol, raclopride, and sulpiride, but not by a D{sub 4} receptor ligand clozapine. In the cortex and cerebellum the uptake was also reduced by D{sub 2}-like receptor ligands with affinity for sigma receptors, but not by raclopride. Although none of seven sigma receptor ligands, SA6298, N,N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]ethylamine hydrochloride (NE-100), (+)-pentazocine, R(-)-N-(3-phenyl-1-propyl)-1-phenyl-2-aminopropane hydrochloride ([-]-PPAP), (-)-pentazocine, R(+)-3-(3-hydroxyphenyl)-N-propylpiperidine hydrochloride ([+]-3-PPP), and (+)-N-allylnormetazocine hydrochloride ([+]-SKF 10047), blocked the striatal uptake, five of them with relatively higher affinity significantly reduced the [{sup 11}C]NEM uptake by the cortex, and four of them reduced that by the cerebellum. We concluded that [{sup 11}C]NEM binds in vivo not only to dopamine D{sub 2}-like receptors in the striatum but also to sigma receptors in other regions such as cortex and cerebellum.

  4. Captive solvent [11C]acetate synthesis in GMP conditions

    Reliable procedure for the production of 1-[11C]acetate in GMP conditions was developed based on a combination of the captive-solvent Grignard reaction conducted in the sterile catheter followed by the convenient solid-phase extraction purification on a series of ion-exchange cartridges. The described procedure proved to be reliable in more than 30 patient productions. The process provides stable radiochemical yields (65% EOB) of sodium acetate (1-[11C]) of the Ph.Eur. quality (radiochemical purity better than 95%) in a short time (5 min)

  5. Synthesis of [O-methyl-{sup 11}C]fluvoxamine - a potential serotonin uptake site radioligand

    Matarrese, M.; Soloviev, D.; Fazio, F. [Consiglio Nazionale delle Ricerche, Milan (Italy); Todde, S.; Magni, F.; Colombo, D.; Galli Kienle, M. [Department of Medical Chemistry and Biochemistry, Milan (Italy)

    1997-06-01

    5-Methoxy-1-[4-(trifluoromethyl)-phenyl]-1-pentanone-0-(2-amin oethyl)oxime (fluvoxamine), a potent clinically used antidepressant, was labelled with carbon-11 (t{sub 1/2} = 20.4 min) as a potential radioligand for the non-invasive assessment of serotonin uptake sites in the human brain with positron emission tomography (PET). The two-step radiochemical synthesis consisted of 0-methylation of an amino-protected desmethyl precursor with [{sup 11}C]methyl iodide under mild conditions in the presence of tetrabutylammonium hydroxide in acetonitrile, followed by deprotection with trifluoroacetic acid. 5-[{sup 11}C]Methoxy-1-[4-(trifluoromethyl)-phenyl]-1-pentanone-0-(2-a minoethyl)oxime was obtained in > 98% radiochemical purity in 40 min with a radiochemical yield of 4 {+-} 2% (non-decay corrected) and a specific radioactivity of 1 {+-} 0.5 Ci/{mu}mol. 5-Hydroxy-1-[4-(trifluoromethyl)-phenyl]-1-pentanone-0-[2-(tert-bu toxycarbonylamino)ethyl]oxime, the precursor for the radiosynthesis of [{sup 11}C]fluvoxamine, was prepared by a convenient three-set synthesis from the pharmaceutical form of fluvoxamine maleate by converting it into the free base, demethylation by trimethyliodosilane and introduction of the BOC-protective group with di-tert-butyl dicarbonate. (author).

  6. Synthesis and in vivo evaluation of [11C]SA6298 as a PET sigma1 receptor ligand

    The potential of a 11C-labeled selective sigma1 receptor ligand, 1-(3,4-dimethoxyphenethyl)-4-[3-(3,4-dichlorophenyl)propyl]piperazine ([11C]SA6298), was evaluated as a positron emission tomography (PET) ligand for mapping sigma1 receptors in the central nervous system and peripheral organs. [11C]SA6298 was synthesized by methylation of the desmethyl SA6298 with [11C]CH3I, with the decay-corrected radiochemical yield of 39±5% based on [11C]CH3I and with the specific activity of 53±17 TBq/mmol within 20 min from end of bombardment (EOB). In mice, the uptake of [11C]SA6298 was significantly decreased by carrier loading in the brain, liver, spleen, heart, lung, small intestine, and kidney in which sigma receptors are present as well as in the skeletal muscle. Pretreatment with SA6298 also blocked the uptake of [11C]SA6298 by these organs except for the small intestine, but significant displacement of [11C]SA6298 by posttreatment with SA6298 was observed only in the heart, lung, and muscle. In the blocking study with one of the eight sigma receptor ligands, including haloperidol, SA6298, NE-100, (+)-pentazocine, SA4503, (-)-pentazocine, (+)-3-PPP, and (+)-SKF 10,047 (in the order of the affinity for sigma1 receptor subtype), only SA6298 and an analog SA4503 significantly reduced the brain uptake of [11C]SA6298 to approximately 80% of the control, but the other six ligands did not. Peripherally, the uptake of [11C]SA6298 by the organs described above was decreased predominantly by SA6298 or SA4503, but the blocking effects of the other five ligands except for NE-100 depended on their affinity for sigma1 receptors. The saturable brain uptake of [11C]SA6298, approximately 20%, was also observed by tissue dissection method in rats and by PET in a cat. Ex vivo autoradiography of the rat brain showed a high uptake in the cortex and thalamus. In the cat brain a relatively high uptake was found in the cortex, thalamus, striatum, and cerebellum. These results have indicated a

  7. Synthesis and PET studies of [11C-cyano]letrozole (Femara), an aromatase inhibitor drug

    Introduction: Aromatase, a member of the cytochrome P450 family, converts androgens such as androstenedione and testosterone into estrone and estradiol, respectively. Letrozole (1-[bis-(4-cyanophenyl)methyl]-1H-1,2,4-triazole; Femara) is a high-affinity aromatase inhibitor (Ki=11.5 nM) that has Food and Drug Administration approval for breast cancer treatment. Here we report the synthesis of carbon-11-labeled letrozole and its assessment as a radiotracer for brain aromatase in the baboon. Methods: Letrozole and its precursor (4-[(4-bromophenyl)-1H-1,2,4-triazol-1-ylmethyl]benzonitrile) were prepared in a two-step synthesis from 4-cyanobenzyl bromide and 4-bromobenzyl bromide, respectively. The [11C]cyano group was introduced via tetrakis(triphenylphosphine)palladium(0)-catalyzed coupling of [11C]cyanide with the bromo precursor. Positron emission tomography (PET) studies in the baboon brain were carried out to assess regional distribution and kinetics, reproducibility of repeated measures and saturability. Log D, the free fraction of letrozole in plasma and the [11C-cyano]letrozole fraction in arterial plasma were also measured. Results: [11C-cyano]Letrozole was synthesized in 60 min with a radiochemical yield of 79-80%, with a radiochemical purity greater than 98% and a specific activity of 4.16±2.21 Ci/μmol at the end of bombardment (n=4). PET studies in the baboon revealed initial rapid and high uptake and initial rapid clearance, followed by slow clearance of carbon-11 from the brain, with no difference between brain regions. Brain kinetics was not affected by coinjection of unlabeled letrozole (0.1 mg/kg). The free fraction of letrozole in plasma was 48.9%, and log D was 1.84. Conclusion: [11C-cyano]Letrozole is readily synthesized via a palladium-catalyzed coupling reaction with [11C]cyanide. Although it is unsuitable as a PET radiotracer for brain aromatase, as revealed by the absence of regional specificity and saturability in brain regions such as

  8. Development of a fully automated and GMP compliant [11C]-radiosynthesis module

    Full text: The automation of routinely produced and GMP compliant [11C]radiotracers is an important process for any PET centre. Automation allows for highly reproducible synthesis with large amount of radioactivity while minimising exposure to the radiochemist. GMP compliance is required to meet the upcoming regulations for PET radio-pharmaceutical production. Based on these requirements, we have designed at the ARMC PET Centre, a reliable and versatile chemistry module for the production of [11C]-radiotracers. This aim has been achieved by using disposable manifolds and tubing in conjunction with newly prepared reaction vessels. Cross-contamination by subsequent productions of different radiophammaceuticals is then fully prevented. Automation of the synthesis sequences is performed by a PLC Siemens (CPU216), and the programs allows for the production of different radiotracers according to their specific reaction parameters such as temperature and reaction time. Relevant digital and analog parameters are measured throughout the synthesis and fed back to the PLC to allow clear monitoring of the process by the user. Our new radiosynthesis module is based on the conventional production of [11C]-methyliodide, followed by its reaction with the relevant precursor at room temperature using the loop technique. The crude labelled product is then automatically injected into the HPLC column. After collection of the pure product, the mobile phase is discarded, and the final product eluted with ethanol and formulated with a physiological solution using the 'SepPak technique'. The synthesis time is about 30 minutes including purification and formulation of the product. The [11C]-radiosynthesis prototype module is currently under evaluation. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc

  9. Low background and high contrast PET imaging of amyloid-{beta} with [{sup 11}C]AZD2995 and [{sup 11}C]AZD2184 in Alzheimer's disease patients

    Forsberg, Anton; Andersson, Jan; Varnaes, Katarina; Halldin, Christer [Karolinska Institutet, Centre for Psychiatry Research, Department of Clinical Neuroscience, Stockholm (Sweden); Jureus, Anders; Swahn, Britt-Marie; Sandell, Johan; Julin, Per; Svensson, Samuel [AstraZeneca Research and Development, Neuroscience Research and Therapy Area, Soedertaelje (Sweden); Cselenyi, Zsolt; Schou, Magnus; Johnstroem, Peter; Farde, Lars [Karolinska Institutet, Centre for Psychiatry Research, Department of Clinical Neuroscience, Stockholm (Sweden); Karolinska Hospital, AstraZeneca Translational Sciences Centre, PET CoE, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm (Sweden); Eriksdotter, Maria; Freund-Levi, Yvonne [Karolinska Institutet, Clinical Geriatrics, Department of Neurobiology, Care Sciences and Society, Stockholm (Sweden); Karolinska University Hospital, Department of Geriatric Medicine, Stockholm (Sweden); Jeppsson, Fredrik [AstraZeneca Research and Development, Neuroscience Research and Therapy Area, Soedertaelje (Sweden); Karolinska Institutet, Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Stockholm (Sweden)

    2013-04-15

    The aim of this study was to evaluate AZD2995 side by side with AZD2184 as novel PET radioligands for imaging of amyloid-{beta} in Alzheimer's disease (AD). In vitro binding of tritium-labelled AZD2995 and AZD2184 was studied and compared with that of the established amyloid-{beta} PET radioligand PIB. Subsequently, a first-in-human in vivo PET study was performed using [{sup 11}C]AZD2995 and [{sup 11}C]AZD2184 in three healthy control subjects and seven AD patients. AZD2995, AZD2184 and PIB were found to share the same binding site to amyloid-{beta}. [{sup 3}H]AZD2995 had the highest signal-to-background ratio in brain tissue from patients with AD as well as in transgenic mice. However, [{sup 11}C]AZD2184 had superior imaging properties in PET, as shown by larger effect sizes comparing binding potential values in cortical regions of AD patients and healthy controls. Nevertheless, probably due to a lower amount of nonspecific binding, the group separation of the distribution volume ratio values of [{sup 11}C]AZD2995 was greater in areas with lower amyloid-{beta} load, e.g. the hippocampus. Both AZD2995 and AZD2184 detect amyloid-{beta} with high affinity and specificity and also display a lower degree of nonspecific binding than that reported for PIB. Overall [{sup 11}C]AZD2184 seems to be an amyloid-{beta} radioligand with higher uptake and better group separation when compared to [{sup 11}C]AZD2995. However, the very low nonspecific binding of [{sup 11}C]AZD2995 makes this radioligand potentially interesting as a tool to study minute levels of amyloid-{beta}. This sensitivity may be important in investigating, for example, early prodromal stages of AD or in the longitudinal study of a disease modifying therapy. (orig.)

  10. Erlotinib-Induced Episcleritis in a Patient with Pancreatic Cancer

    Armin Shahrokni

    2008-03-01

    Full Text Available Context Erlotinib is a relatively new anilinoquinazoline indicated for treatment of pancreatic cancer in combination with gemcitabine. It is a tyrosine kinase inhibitor that specifically targets epidermal growth factor receptor (EGFR, which is commonly overexpressed and/or mutated in solid tumors. Active competitive inhibition of adenosine triphosphate, inhibits downstream signal transduction of ligand dependent EGFR activation. EGFR kinase inhibitors are less toxic than conventional chemotherapy as they are relatively specific for tumor cells. Common side effects include acneiform (papulopustular rash, diarrhea, edema, pruritus, dry skin and alopecia. Case report This article reports the case of a 55-year-old Caucasian female with recurrent pancreatic cancer who developed episcleritis after seventeen days of treatment with erlotinib. Symptoms completely resolved four weeks after drug discontinuation. Conclusions To our knowledge, erlotinibinduced episcleritis has not been previously described.

  11. Synthesis of two potential NK1-receptor ligands using [1-11C]ethyl iodide and [1-11C]propyl iodide and initial PET-imaging

    The previously validated NK1-receptor ligand [O-methyl-11C]GR205171 binds with a high affinity to the NK1-receptor and displays a slow dissociation from the receptor. Hence, it cannot be used in vivo for detecting concentration changes in substance P, the endogenous ligand for the NK1-receptor. A radioligand used for monitoring these changes has to enable displacement by the endogenous ligand and thus bind reversibly to the receptor. Small changes in the structure of a receptor ligand can lead to changes in binding characteristics and also in the ability to penetrate the blood-brain barrier. The aim of this study was to use carbon-11 labelled ethyl and propyl iodide with high specific radioactivity in the synthesis of two new and potentially reversible NK1-receptor ligands with chemical structures based on [O-methyl-11C]GR205171. [1-11C]Ethyl and [1-11C]propyl iodide with specific radioactivities of 90 GBq/μmol and 270 GBq/μmol, respectively, were used in the synthesis of [O-methyl-11C]GR205171 analogues by alkylation of O-desmethyl GR205171. The brain uptake of the obtained (2S,3S)-N-(1-(2- [1-11C]ethoxy-5-(3-(trifluoromethyl)-4H-1,2,4-triazol-4-yl)phenyl)ethyl)-2 -phenylpiperidin-3-amine (I) and (2S,3S)-2-phenyl-N-(1-(2- [1-11C]propoxy-5-(3-(trifluoromethyl)-4H-1,2,4-triazol-4-yl)phenyl)ethyl) piperidin-3-amine (II) was studied with PET in guinea pigs and rhesus monkeys and compared to the uptake of [O-methyl-11C]GR205171. All ligands had similar uptake distribution in the guinea pig brain. The PET-studies in rhesus monkeys showed that (II) had no specific binding in striatum. Ligand (I) had moderate specific binding compared to the [O-methyl-11C]GR205171. The ethyl analogue (I) displayed reversible binding characteristics contrary to the slow dissociation rate shown by [O-methyl-11C]GR205171. The propyl-analogue (II) cannot be used for detecting changes in NK1-ligand levels, while further studies should be performed with the ethyl-analogue (I)

  12. [11C]Sorafenib: Radiosynthesis and preclinical evaluation in tumor-bearing mice of a new TKI-PET tracer

    Introduction: Tyrosine kinase inhibitors (TKIs) like sorafenib are important anticancer therapeutics with thus far limited treatment response rates in cancer patients. Positron emission tomography (PET) could provide the means for selection of patients who might benefit from TKI treatment, if suitable PET tracers would be available. The aim of this study was to radiolabel sorafenib (1) with carbon-11 and to evaluate its potential as TKI-PET tracer in vivo. Methods: Synthetic methods were developed in which sorafenib was labeled at two different positions, followed by a metabolite analysis in rats and a PET imaging study in tumor-bearing mice. Results: [methyl-11C]-1 and [urea-11C]-1 were synthesized in yields of 59% and 53%, respectively, with a purity of > 99%. The identity of the products was confirmed by coinjection on HPLC with reference sorafenib. In an in vivo metabolite analysis [11C]sorafenib proved to be stable. The percentage of intact product in blood–plasma after 45 min was 90% for [methyl-11C]-1 and 96% for [urea-11C]-1, respectively. Due to the more reliable synthesis, further research regarding PET imaging was performed with [methyl-11C]-1 in nude mice bearing FaDu (head and neck cancer), MDA-MB-231 (breast cancer) or RXF393 (renal cancer) xenografts. Highest tracer accumulation at a level of 2.52 ± 0.33 %ID/g was observed in RXF393, a xenograft line extensively expressing the sorafenib target antigen Raf-1 as assessed by immunohistochemistry. Conclusion: In conclusion, we have synthesized [11C]sorafenib as PET tracer, which is stable in vivo and has the capability to be used as PET tracer for imaging in tumor-bearing mice

  13. Fatal interstitial lung disease associated with oral erlotinib therapy for lung cancer

    Erlotinib is a Human Epidermal Growth Factor Receptor Type 1/tyrosine kinase (EGFR) inhibitor which is used for non-small-cell lung cancer treatment. Despite that erlotinib is considered to have a favorable safety profile, adverse events such as interstitial lung disease (ILD) were reported in pivotal studies. The authors report the first histologically confirmed case of fatal ILD associated with erlotinib therapy. The medical record of a patient who developed fatal ILD after receiving erlotinib treatment was reviewed to identify the cause of death and other factors potentially contributive to this adverse outcome. A 55-year-old smoker with no evidence of pre-existing interstitial disease developed bilateral ILD and respiratory failure which could be explained only as a toxicity of erlotinib. He had a history of stage IV left upper lobe squamous-cell carcinoma for which he had received three successive regimens of chemotherapy (ifosfamide plus gemcitabine, docetaxel, mitomycin plus navelbine), followed five months later by erlotinib. At initiation of erlotinib treatment there were no radiological signs suggestive of ILD disease or apparent clinical signs of respiratory distress. While the patient completed two months with erlotinib therapy he developed bilateral interstitial infiltrates; despite discontinuation of erlotinib he was admitted with respiratory failure two weeks later. Diagnostic work up for other causes of pneumonitis including infectious diseases, congestive cardiac failure and pulmonary infraction was negative. Empiric treatment with oxygene, corticosteroids and later with cyclophosphamide was ineffective and the patient progressively deteriorated and died. The clinical and post-mortem examination findings are presented and the possible association relationship between erlotinib induced ILD and previous chemotherapy is discussed. Physicians should be alert to the fact that erlotinib related ILD, although infrequent, is potential fatal. The

  14. Automatic synthesis of [11C]raclopride and initial clinical application on Parkinson's disease

    Full text: Background/Aim: Parkinson's disease is a common neurological degenerative disease. The change of dopamine D2 receptors is of great importance in its mechanism. [11C]Raclopride is a PET radiotracer for dopamine D2 receptor. Establish a methods for automatic synthesis of [11]Raclopride on GE Tracerlab FXc. Investigate the changes of dopamine D2 receptor in Parkinson's disease patients after the introduction of piribedil with [11C]Raclopride PET/CT. Materials and Methods: [11'C]CO2 produced by cyclotron was converted to [11C]CH3I via gas phase iodination. [11C]CH3I was bubbled into a reactor vessel contained 0.2ml of DMSO with 1mg precursor, demethyl-Raclopride, and 5μI of 8M NaOH. The reactor was heated to 700C for 5 minutes for labelling reaction and then the product was separated by HPLC. The HPLC eluent containing the product diluted by 80ml of water and passed through a plus C 18 cartridge. The cartridge was washed with 10 ml water, 2 times then eluted by I ml of ethanol. The ethanol was diluted with 10ml saline and the mixture passed through a 0.22μm filter to a sterilized vial. The final product was analysed by HPLC and had sterilization and pyrogen test. 6 patients of Parkinson's disease without therapy, 4 patients after piribedil therapy with mean age of 66.6±7.20 and mean disease duration 2.6±1.33 years and 4 volunteers with mean age of 69.75±2.63 took part in the test. All of them underwent [11C]raclopride PET/CT examination, with ten serial 1 minute, ten 2-minutes, and thereafter six 3.33-minutes time frames over the period of 50 minutes, providing a total of 26 time frames. After reconstruction, 16-26 frames were selected to calculate the bindings. The [11C]raclopride binding index was defined as an uptake ratio of striatum to cerebellum. Result: Total synthesis time from transfer [11C]CO, to synthesis finished is 40 min. The final yield without decay corrected is about 5%. The radiochemistry purity is more than 98%. The final product

  15. Mild synthesis of [N-methyl-11C]-isovaleroyl-(L)-carnitine. The usefulness of a tritium approach

    The title carnitine derivative was labelled both with [11C]methyl iodide and [3H]methyl iodide. The former was synthesized in order to improve the knowledge of the acyl carnitines fate in humans. The latter was synthesized, at approximately the same concentration level as that of the former, in order to optimize its radiosynthesis, taking advantage from the long half-life of the tritium

  16. Mild synthesis of [N-methyl-{sup 11}C]-isovaleroyl-(L)-carnitine. The usefulness of a tritium approach

    Angelini, G.; Carnevaletti, F.; Margonelli, A.; Corsi, G. [Istituto di Chimica Nucleare - C.N.R., C.P. 10, Rome (Italy); Ragni, P. [Istituto di Chimica Nucleare -- C.N.R., C.P. 10 -- 00016 Monterotondo Stazione, Roma, (Italy); Fazio, F.; Todde, S. [Istituto di Neuroscienze e Bioimmagini - C.N.R., H.S. Raffaele, Milan (Italy); Tinti, O. [Sigma-Tau, Industrie Farmaceutiche Riunite S.p.A., Pomezia, Rome (Italy)

    1999-02-01

    The title carnitine derivative was labelled both with [{sup 11}C]methyl iodide and [{sup 3}H]methyl iodide. The former was synthesized in order to improve the knowledge of the acyl carnitines fate in humans. The latter was synthesized, at approximately the same concentration level as that of the former, in order to optimize its radiosynthesis, taking advantage from the long half-life of the tritium.

  17. Hot reactions in the systems 11C/H2O(l), 11C/H2O-NH3(l) and 13N/H2O(g)

    The chemical reactions of hot 11C with liquid water and a water ammonia mixture of mass ratio 3:1 and of 13N with water vapour were studied at T = 295 K. 11C was generated by the nuclear processes 16O(p,α,pn)11C and 14N(p,α)11C. 13N was produced via the 16O(p,α)13N nuclear reaction. The proton radiation dose was varied from D* = 2.8x10-3 to 0.28 eV per target molecule for the system 11C/H2O(l), from D* = 2.2 to 32 eV for the system 11C/H2O-NH3(l) and from D* = 0.13 to 6.2 eV for the system 13N/H2O(g), in order to follow radiolytic changes of the reaction products. Products of the system 11C/H2O(l) were 11CO2 (98-100% radiochemical yield) and 11CO (max. 1.5%). For the system 11C/H2O-NH3(l) six products (11CO2, 11CO, H11COOH, 11CH2O, 11CH3OH and 11CH4) were observed at radiation doses up to D* = 32 eV. In the system 13N/H2O(g) five products were detected: 13NO2, 13NO, 13NN, 13NNO and some 13NH3. 13NO is the main product at lowest doses with radiochemical yields exceeding 45%. With increasing radiolysis 13NO is changed to 13NO2. At higher doses 13NN becomes the main product. The system 11C/H2O-NH3(l) seems to bear some importance for the production of labelled precursors for the synthesis of radiopharmaceuticals. The interesting products 11CH2O and 11CH3OH are still formed under intensive irradiation which is necessary for the production of high radioactivities for nuclear medical application. (orig./RB)

  18. Imaging of I{sub 2}-imidazoline receptors by small-animal PET using 2-(3-fluoro-[4-{sup 11}C]tolyl)-4,5-dihydro-1H-imidazole ([{sup 11}C]FTIMD)

    Kawamura, Kazunori, E-mail: kawamur@nirs.go.j [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Naganawa, Mika [Department of Biophysics, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Konno, Fujiko; Yui, Joji [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Wakizaka, Hidekatsu [Department of Biophysics, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Yamasaki, Tomoteru; Yanamoto, Kazuhiko; Hatori, Akiko [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Takei, Makoto [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Tokyo Nuclear Services Co., Ltd., Tokyo 110-0016 (Japan); Yoshida, Yuichiro [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); SHI Accelerator Service Ltd., Tokyo 141-0032 (Japan); Sakaguchi, Kazuya [Department of Biophysics, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Fukumura, Toshimitsu [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Kimura, Yuichi [Department of Biophysics, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Zhang, Ming-Rong [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan)

    2010-07-15

    Introduction: Imidazoline receptors (IRs) have been established as distinct receptors, and have been categorized into at least two subtypes (I{sub 1}R and I{sub 2}R). I{sub 2}Rs are associated with depression, Alzheimer's disease, Huntington's disease and Parkinson's disease. A few positron emission tomography (PET) probes for I{sub 2}Rs have been synthesized, but a selective PET probe has not been evaluated for the imaging of I{sub 2}Rs by PET. We labeled a selective I{sub 2}R ligand 2-(3-fluoro-4-tolyl)-4,5-dihydro-1H-imidazole (FTIMD) with {sup 11}C and performed the first imaging of I{sub 2}Rs by PET using 2-(3-fluoro-[4-{sup 11}C]tolyl)-4,5-dihydro-1H-imidazole ([{sup 11}C]FTIMD). Methods: [{sup 11}C]FTIMD was prepared by a palladium-promoted cross-coupling reaction of the tributylstannyl precursor and [{sup 11}C]methyl iodide in the presence of tris(dibenzylideneacetone)dipalladium(0) and tri(o-tol)phosphine. Biodistribution was investigated in rats by tissue dissection. [{sup 11}C]FTIMD metabolites were measured in brain tissues and plasma. Dynamic PET scans were acquired in rats, and the kinetic parameters estimated. Results: [{sup 11}C]FTIMD was successfully synthesized with a suitable radioactivity for the injection. Co-injection with 0.1 mg/kg of cold FTIMD and BU224 induced a significant reduction in the brain-to-blood ratio 15 and 30 min after the injection. In metabolite analysis, unchanged [{sup 11}C]FTIMD in the brain was high (98%) 30 min after the injection. In PET studies, high radioactivity levels were observed in regions with a high density of I{sub 2}R. The radioactivity levels and V{sub T} values in the brain regions were prominently reduced by 1.0 mg/kg of BU224 pretreatment as compared with control. Conclusion: [{sup 11}C]FTIMD showed specific binding to I{sub 2}Rs in rat brains with a high density of I{sub 2}R.

  19. Imaging of I2-imidazoline receptors by small-animal PET using 2-(3-fluoro-[4-11C]tolyl)-4,5-dihydro-1H-imidazole ([11C]FTIMD)

    Introduction: Imidazoline receptors (IRs) have been established as distinct receptors, and have been categorized into at least two subtypes (I1R and I2R). I2Rs are associated with depression, Alzheimer's disease, Huntington's disease and Parkinson's disease. A few positron emission tomography (PET) probes for I2Rs have been synthesized, but a selective PET probe has not been evaluated for the imaging of I2Rs by PET. We labeled a selective I2R ligand 2-(3-fluoro-4-tolyl)-4,5-dihydro-1H-imidazole (FTIMD) with 11C and performed the first imaging of I2Rs by PET using 2-(3-fluoro-[4-11C]tolyl)-4,5-dihydro-1H-imidazole ([11C]FTIMD). Methods: [11C]FTIMD was prepared by a palladium-promoted cross-coupling reaction of the tributylstannyl precursor and [11C]methyl iodide in the presence of tris(dibenzylideneacetone)dipalladium(0) and tri(o-tol)phosphine. Biodistribution was investigated in rats by tissue dissection. [11C]FTIMD metabolites were measured in brain tissues and plasma. Dynamic PET scans were acquired in rats, and the kinetic parameters estimated. Results: [11C]FTIMD was successfully synthesized with a suitable radioactivity for the injection. Co-injection with 0.1 mg/kg of cold FTIMD and BU224 induced a significant reduction in the brain-to-blood ratio 15 and 30 min after the injection. In metabolite analysis, unchanged [11C]FTIMD in the brain was high (98%) 30 min after the injection. In PET studies, high radioactivity levels were observed in regions with a high density of I2R. The radioactivity levels and VT values in the brain regions were prominently reduced by 1.0 mg/kg of BU224 pretreatment as compared with control. Conclusion: [11C]FTIMD showed specific binding to I2Rs in rat brains with a high density of I2R.

  20. An efficient synthesis of 2-[carbonyl-11C]acetamido-2-deoxy-D-glucopyranose (N-[carbonyl-11C]acetyl-D-glucosamine)

    A rapid chemical synthesis of 2-[carbonyl-11C]acetamido-2-deoxy-D-glucopyranose (N-[carbonyl-11C]acetyl-D-glucosamine) starting from [11C]carbon dioxide is described. The total time required for the synthesis, the radiochemical yield, and purity of the titled sugar are ca. 60 min, 49.5% (based on [carbonyl-11C] acetic acid), and >98%, respectively. (author)

  1. Short-lived positron emitter labeled radiotracers - present status

    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 (11C, 18F, 13N) labelled tracers for PETT. Synthesis of labelled sugars, amino acids, and neurotransmitter receptors (pimozide and spiroperidol tagged with 11C) is discussed in particular

  2. [{sup 11}C]-MeJDTic: a novel radioligand for {kappa}-opioid receptor positron emission tomography imaging

    Poisnel, Geraldine; Oueslati, Farhana; Dhilly, Martine; Delamare, Jerome [Groupe de Developpements Methodologiques en Tomographie par Emission de Positons, DSV/DRM UMR CEA 2E, Universite de Caen-Basse Normandie, Centre Cyceron, 14074 Caen Cedex (France); Perrio, Cecile [Groupe de Developpements Methodologiques en Tomographie par Emission de Positons, DSV/DRM UMR CEA 2E, Universite de Caen-Basse Normandie, Centre Cyceron, 14074 Caen Cedex (France)], E-mail: perrio@cyceron.fr; Debruyne, Daniele [Groupe de Developpements Methodologiques en Tomographie par Emission de Positons, DSV/DRM UMR CEA 2E, Universite de Caen-Basse Normandie, Centre Cyceron, 14074 Caen Cedex (France)], E-mail: debruyne@cyceron.fr; Barre, Louisa [Groupe de Developpements Methodologiques en Tomographie par Emission de Positons, DSV/DRM UMR CEA 2E, Universite de Caen-Basse Normandie, Centre Cyceron, 14074 Caen Cedex (France)

    2008-07-15

    Introduction: Radiopharmaceuticals that can bind selectively the {kappa}-opioid receptor may present opportunities for staging clinical brain disorders and evaluating the efficiency of new therapies related to stroke, neurodegenerative diseases or opiate addiction. The N-methylated derivative of JDTic (named MeJDTic), which has been recently described as a potent and selective antagonist of {kappa}-opioid receptor in vitro, was labeled with carbon-11 and evaluated for in vivo imaging the {kappa}-opioid receptor in mice. Methods: [{sup 11}C]-MeJDTic was prepared by methylation of JDTic with [{sup 11}C]-methyl triflate. The binding of [{sup 11}C]-MeJDTic to {kappa}-opioid receptor was investigated ex vivo by biodistribution and competition studies using nonfasted male CD1 mice. Results: [{sup 11}C]-MeJDTic exhibited a high and rapid distribution in peripheral organs. The uptake was maximal in lung where the {kappa} receptor is largely expressed. [{sup 11}C]-MeJDTic rapidly crossed the blood-brain barrier and accumulated in the brain regions of interest (hypothalamus). The parent ligand remained the major radioactive compound in brain during the experiment. Chase studies with U50,488 (a {kappa} referring agonist), morphine (a {mu} agonist) and naltrindole (a {delta} antagonist) demonstrated that this uptake was the result of specific binding to the {kappa}-opioid receptor. Conclusion: These findings suggested that [{sup 11}C]-MeJDTic appeared to be a promising selective 'lead' radioligand for {kappa}-opioid receptor PET imaging.

  3. PET imaging of focal demyelination and remyelination in a rat model of multiple sclerosis: comparison of [{sup 11}C]MeDAS, [{sup 11}C]CIC and [{sup 11}C]PIB

    Paula Faria, Daniele de [University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Groningen (Netherlands); University of Groningen, University Medical Center Groningen, Department of Neuroscience, Groningen (Netherlands); University of Sao Paulo Medical School, Center of Nuclear Medicine, Sao Paulo (Brazil); Copray, Sjef [University of Groningen, University Medical Center Groningen, Department of Neuroscience, Groningen (Netherlands); Sijbesma, Jurgen W.A.; Willemsen, Antoon T.M.; Dierckx, Rudi A.J.O.; Vries, Erik F.J. de [University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Groningen (Netherlands); Buchpiguel, Carlos A. [University of Sao Paulo Medical School, Center of Nuclear Medicine, Sao Paulo (Brazil)

    2014-05-15

    In this study, we compared the ability of [{sup 11}C]CIC, [{sup 11}C]MeDAS and [{sup 11}C]PIB to reveal temporal changes in myelin content in focal lesions in the lysolecithin rat model of multiple sclerosis. Pharmacokinetic modelling was performed to determine the best method to quantify tracer uptake. Sprague-Dawley rats were stereotactically injected with either 1 % lysolecithin or saline into the corpus callosum and striatum of the right brain hemisphere. Dynamic PET imaging with simultaneous arterial blood sampling was performed 7 days after saline injection (control group), 7 days after lysolecithin injection (demyelination group) and 4 weeks after lysolecithin injection (remyelination group). The kinetics of [{sup 11}C]CIC, [{sup 11}C]MeDAS and [{sup 11}C]PIB was best fitted by Logan graphical analysis, suggesting that tracer binding is reversible. Compartment modelling revealed that all tracers were fitted best with the reversible two-tissue compartment model. Tracer uptake and distribution volume in lesions were in agreement with myelin status. However, the slow kinetics and homogeneous brain uptake of [{sup 11}C]CIC make this tracer less suitable for in vivo PET imaging. [{sup 11}C]PIB showed good uptake in the white matter in the cerebrum, but [{sup 11}C]PIB uptake in the cerebellum was low, despite high myelin density in this region. [{sup 11}C]MeDAS distribution correlated well with myelin density in different brain regions. This study showed that PET imaging of demyelination and remyelination processes in focal lesions is feasible. Our comparison of three myelin tracers showed that [{sup 11}C]MeDAS has more favourable properties for quantitative PET imaging of demyelinated and remyelinated lesions throughout the CNS than [{sup 11}C]CIC and [{sup 11}C]PIB. (orig.)

  4. PET imaging of focal demyelination and remyelination in a rat model of multiple sclerosis: comparison of [11C]MeDAS, [11C]CIC and [11C]PIB

    In this study, we compared the ability of [11C]CIC, [11C]MeDAS and [11C]PIB to reveal temporal changes in myelin content in focal lesions in the lysolecithin rat model of multiple sclerosis. Pharmacokinetic modelling was performed to determine the best method to quantify tracer uptake. Sprague-Dawley rats were stereotactically injected with either 1 % lysolecithin or saline into the corpus callosum and striatum of the right brain hemisphere. Dynamic PET imaging with simultaneous arterial blood sampling was performed 7 days after saline injection (control group), 7 days after lysolecithin injection (demyelination group) and 4 weeks after lysolecithin injection (remyelination group). The kinetics of [11C]CIC, [11C]MeDAS and [11C]PIB was best fitted by Logan graphical analysis, suggesting that tracer binding is reversible. Compartment modelling revealed that all tracers were fitted best with the reversible two-tissue compartment model. Tracer uptake and distribution volume in lesions were in agreement with myelin status. However, the slow kinetics and homogeneous brain uptake of [11C]CIC make this tracer less suitable for in vivo PET imaging. [11C]PIB showed good uptake in the white matter in the cerebrum, but [11C]PIB uptake in the cerebellum was low, despite high myelin density in this region. [11C]MeDAS distribution correlated well with myelin density in different brain regions. This study showed that PET imaging of demyelination and remyelination processes in focal lesions is feasible. Our comparison of three myelin tracers showed that [11C]MeDAS has more favourable properties for quantitative PET imaging of demyelinated and remyelinated lesions throughout the CNS than [11C]CIC and [11C]PIB. (orig.)

  5. Ganoderma lucidum Combined with the EGFR Tyrosine Kinase Inhibitor, Erlotinib Synergize to Reduce Inflammatory Breast Cancer Progression.

    Suárez-Arroyo, Ivette J; Rios-Fuller, Tiffany J; Feliz-Mosquea, Yismeilin R; Lacourt-Ventura, Mercedes; Leal-Alviarez, Daniel J; Maldonado-Martinez, Gerónimo; Cubano, Luis A; Martínez-Montemayor, Michelle M

    2016-01-01

    The high incidence of resistance to Tyrosine Kinase Inhibitors (TKIs) targeted against EGFR and downstream pathways has increased the necessity to identify agents that may be combined with these therapies to provide a sustained response for breast cancer patients. Here, we investigate the therapeutic potential of Ganoderma lucidum extract (GLE) in breast cancer, focusing on the regulation of the EGFR signaling cascade when treated with the EGFR TKI, Erlotinib. SUM-149, or intrinsic Erlotinib resistant MDA-MB-231 cells, and a successfully developed Erlotinib resistant cell line, rSUM-149 were treated with increasing concentrations of Erlotinib, GLE, or their combination (Erlotinib/GLE) for 72h. Treatment effects were tested on cell viability, cell proliferation, cell migration and invasion. To determine tumor progression, severe combined immunodeficient mice were injected with SUM-149 cells and then treated with Erlotinib/GLE or Erlotinib for 13 weeks. We assessed the protein expression of ERK1/2 and AKT in in vitro and in vivo models. Our results show that GLE synergizes with Erlotinib to sensitize SUM-149 cells to drug treatment, and overcomes intrinsic and developed Erlotinib resistance. Also, Erlotinib/GLE decreases SUM-149 cell viability, proliferation, migration and invasion. GLE increases Erlotinib sensitivity by inactivating AKT and ERK signaling pathways in our models. We conclude that a combinatorial therapeutic approach may be the best way to increase prognosis in breast cancer patients with EGFR overexpressing tumors. PMID:26958085

  6. A new visualization technique for the study of the accumulation of photoassimilates in wheat grains using [11C]CO2

    Non-invasive real-time visualization of the accumulation of photoassimilates in the grains of an ear of wheat using [11C]CO2 and positron emitting tracer imaging system (PETIS) was studied. [11C]CO2 was supplied to the center of a fully expanded leaf of a wheat plant for an initial 10 min, and the transportation of 11C-labeled photoassimilates into the grains of the ear was monitored for 120 min using the PETIS. Each grain was clearly identified in the obtained animation. The 11C-labeled photoassimilates arrived at the ear from the [11C]CO2-absorbing leaf within 53 min from the time of supplying [11C]CO2. After that, grains appeared on the image one by one from the basal part and full images of the grains appeared within 20 min. The time course of the accumulation of photoassimilates into each grain showed a different profile. Furthermore, the PETIS data suggested that the photo-condition of the ear plays an important role in the transportation of photoassimilates in wheat. PETIS can be used to visualize the dynamics of the substances in a living plant in real time and can exhibit the time course analysis of substances, such as the transportation, distribution, and accumulation

  7. Cryogenic molecular separation system for radioactive 11C ion acceleration

    A 11C molecular production/separation system (CMPS) has been developed as part of an isotope separation on line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive 11C ion beams. In the ISOL system, 11CH4 molecules will be produced by proton irradiation and separated from residual air impurities and impurities produced during the irradiation. The CMPS includes two cryogenic traps to separate specific molecules selectively from impurities by using vapor pressure differences among the molecular species. To investigate the fundamental performance of the CMPS, we performed separation experiments with non-radioactive 12CH4 gases, which can simulate the chemical characteristics of 11CH4 gases. We investigated the separation of CH4 molecules from impurities, which will be present as residual gases and are expected to be difficult to separate because the vapor pressure of air molecules is close to that of CH4. We determined the collection/separation efficiencies of the CMPS for various amounts of air impurities and found desirable operating conditions for the CMPS to be used as a molecular separation device in our ISOL system

  8. Different sensitivities to competitive inhibition of benzodiazepine receptor binding of 11C-iomazenil and 11C-flumazenil in rhesus monkey brain

    The in vivo binding kinetics of 11C-iomazenil were compared with those of 11C-flumazenil binding in rhesus monkey brain. The monkey was anesthetized with ketamine and intravenously injected with either 11C-iomazenil or 11C-flumazenil in combination with the coadministration of different doses of non-radioactive flumazenil (0, 5 and 20 μg/kg). The regional distribution of 11C-iomazenil in the brain was similar to that of 11C-flumazenil, but the sensitivity of 11C-iomazenil binding to competitive inhibition by non-radioactive flumazenil was much less than that of 11C-flumazenil binding. A significant reduction in 11C-flumazenil binding in the cerebral cortex was observed with 20 μg/kg of flumazenil, whereas a relatively smaller inhibition of 11C-iomazenil binding in the same region was observed with the same dose of flumazenil. These results suggest that 11C-flumazenil may be a superior radiotracer for estimating benzodiazepine receptor occupancy in the intact brain. (author)

  9. Different sensitivities to competitive inhibition of benzodiazepine receptor binding of {sup 11}C-iomazenil and {sup 11}C-flumazenil in rhesus monkey brain

    Inoue, Osamu; Hosoi, Rie; Kobayashi, Kaoru [Osaka Univ., Suita (Japan). Medical School; Itoh, Takashi; Gee, A.; Suzuki, Kazutoshi

    2001-04-01

    The in vivo binding kinetics of {sup 11}C-iomazenil were compared with those of {sup 11}C-flumazenil binding in rhesus monkey brain. The monkey was anesthetized with ketamine and intravenously injected with either {sup 11}C-iomazenil or {sup 11}C-flumazenil in combination with the coadministration of different doses of non-radioactive flumazenil (0, 5 and 20 {mu}g/kg). The regional distribution of {sup 11}C-iomazenil in the brain was similar to that of {sup 11}C-flumazenil, but the sensitivity of {sup 11}C-iomazenil binding to competitive inhibition by non-radioactive flumazenil was much less than that of {sup 11}C-flumazenil binding. A significant reduction in {sup 11}C-flumazenil binding in the cerebral cortex was observed with 20 {mu}g/kg of flumazenil, whereas a relatively smaller inhibition of {sup 11}C-iomazenil binding in the same region was observed with the same dose of flumazenil. These results suggest that {sup 11}C-flumazenil may be a superior radiotracer for estimating benzodiazepine receptor occupancy in the intact brain. (author)

  10. Transition metal mediated [(11) C]carbonylation reactions: recent advances and applications.

    Kealey, Steven; Gee, Antony; Miller, Philip W

    2014-04-01

    [(11) C]Carbon monoxide is undoubtedly a highly versatile radiolabelling synthon with many potential applications for the synthesis of positron emission tomography (PET) tracer molecules and functional groups, but why has it not found more applications in the PET radiolabelling arena? Today, (11) CO radiolabelling is still primarily viewed as a niche area; however, there are signs that this is beginning to change as some of the technical and chemistry challenges of producing, handling and reacting (11) CO are overcome. This mini review covers the more recent developments of (11) CO-labelling chemistry and is focused on palladium and rhodium-mediated carbonylation reactions that are growing in importance and finding wider application for carbon-11 PET radiotracer development. PMID:24425679

  11. In vivo evaluation of [{sup 11}C]SA4503 as a PET ligand for mapping CNS sigma{sub 1} receptors

    Kawamura, Kazunori; Ishiwata, Kiichi E-mail: ishiwata@pet.tmig.or.jp; Tajima, Hisashi; Ishii, Shin-Ichi; Matsuno, Kiyoshi; Homma, Yoshio; Senda, Michio

    2000-04-01

    The potential of the {sup 11}C-labeled selective sigma{sub 1} receptor ligand 1-(3,4-dimethoxyphenethyl)-4-(3-phenylpropyl)piperazine ([{sup 11}C]SA4503) was evaluated in vivo as a positron emission tomography (PET) ligand for mapping sigma{sub 1} receptors in rats. SA4503 is known to have a high affinity (IC{sub 50} 17.4 nM) and a higher selectivity (sigma{sub 1}/sigma{sub 2}=103) for the sigma{sub 1} receptor. A high and increasing brain uptake of [{sup 11}C]SA4503 was found. Pre-, co- and postinjection of cold SA4503 significantly decreased uptake of [{sup 11}C]SA4503 in the brain, spleen, heart, lung, and kidney in which sigma receptors are present as well as in the skeletal muscle. In the blocking study with one of four sigma receptor ligands including haloperidol, (+)-pentazocine, SA4503, and (-)-pentazocine (in the order of their affinity for sigma{sub 1} receptor subtype), SA4503 and haloperidol significantly reduced the brain uptake of [{sup 11}C]SA4503 to approximately 30% of the control, but the other two benzomorphans did not. A high specific uptake of [{sup 11}C]SA4503 by the brain was also confirmed by ex vivo autoradiography (ARG) and PET. Ex vivo ARG showed a higher uptake in the vestibular nucleus, temporal cortex, cingulate cortex, inferior colliculus, thalamus, and frontal cortex, and a moderate uptake in the parietal cortex and caudate putamen. Peripherally, the blocking effects of the four ligands depended on their affinity for sigma{sub 1} receptors. No {sup 11}C-labeled metabolite was detected in the brain 30 min postinjection, whereas approximately 20% of the radioactivity was found as {sup 11}C-labeled metabolites in plasma. These results have demonstrated that the {sup 11}C-labeled sigma{sub 1} receptor ligand [{sup 11}C]SA4503 has a potential for mapping sigma{sub 1} receptors in the central nervous system and peripheral organs.

  12. Assessment of cerebral P-glycoprotein expression and function with PET by combined [11C]inhibitor and [11C]substrate scans in rats

    Introduction: The adenosine triphosphate-binding cassette (ABC) transporter P-glycoprotein (Pgp) protects the brain from accumulation of lipophilic compounds by active efflux transport across the blood–brain barrier. Changes in Pgp function/expression may occur in neurological disorders, such as epilepsy, Alzheimer’s or Parkinson’s disease. In this work we investigated the suitability of the radiolabeled Pgp inhibitors [11C]elacridar and [11C]tariquidar to visualize Pgp density in rat brain with PET. Methods: Rats underwent a first PET scan with [11C]elacridar (n = 5) or [11C]tariquidar (n = 6) followed by a second scan with the Pgp substrate (R)-[11C]verapamil after administration of unlabeled tariquidar at a dose which half-maximally inhibits cerebral Pgp (3 mg/kg). Compartmental modeling using an arterial input function and Logan graphical analysis were used to estimate rate constants and volumes of distribution (VT) of radiotracers in different brain regions. Results: Brain PET signals of [11C]elacridar and [11C]tariquidar were very low (∼ 0.5 standardized uptake value, SUV). There was a significant negative correlation between VT and K1 (i.e. influx rate constant from plasma into brain) values of [11C]elacridar or [11C]tariquidar and VT and K1 values of (R)-[11C]verapamil in different brain regions which was consistent with binding of [11C]inhibitors to Pgp and efflux of (R)-[11C]verapamil by Pgp. Conclusion: The small Pgp binding signals obtained with [11C]elacridar and [11C]tariquidar limit the applicability of these tracers to measure cerebral Pgp density. PET tracers with higher (i.e. subnanomolar) binding affinities will be needed to visualize the low density of Pgp in brain

  13. Imaging of Carrageenan-Induced Local Inflammation and Adjuvant-Induced Systemic Arthritis with [11C]PBR28 PET

    Shao, Xia; Wang, Xueding; English, Sean J; Desmond, Timothy; Sherman, Phillip S; Quesada, Carole A; Piert, Morand R

    2013-01-01

    Introduction [11C]PBR28 binding to translocator protein (TSPO) was evaluated for imaging of acute and chronic inflammation using two established rat models. Methods Acute inflammation was induced by local Carrageenan-injection into the paw of Fisher 344 rats (model A). T-cell mediated adjuvant arthritis was induced by heat-inactivated Mycobacterium butyricum injection in Lewis rats (model B). Micro-PET scan was performed after injection of approximately 35 MBq [11C]PBR28. In model A, volumes of interest (VOIs) were defined in the paw of Fisher 344 rats (n=6) with contralateral sham treatment as control. For model B, VOIs were defined in the tail, sacroiliac joints, hips, knees and thigh muscles of M. butyricum treated animals (n=8) and compared with sham-treated controls (n=4). The peak 11C-PBR28 SUV (SUVpeak) and area under the curve (AUCSUV) of 60-minute time-activity data were calculated. Immunohistochemistry for CD68, a macrophage stain, was performed from paw tissues. In addition, the [11C]PBR28 cell uptake was measured in lipopolysaccharide (LPS)-stimulated and non-stimulated macrophage cultures. Results LPS-stimulated macrophages displayed dose-dependent increased [11C]PBR28 uptake, which was blocked by non-labeled PBR28. In both models, radiotracer uptake of treated lesions increased rapidly within minutes and displayed overall accumulative kinetics. The SUVpeak and AUCSUV of Carrageenan-treated paws was significantly increased compared to controls. Also, the [11C]PBR28 uptake ratio of Carrageenan-treated vs. sham-treated paw correlated significantly with CD68 staining ratios of the same animals. In adjuvant arthritis, significantly increased [11C]PBR28 SUVpeak and AUCSUV values were identified at the tail, knees, and sacroiliac joints, while no significant differences were identified in the lumbar spine and hips. Conclusions Based on our initial data, [11C]PBR28 PET appears to have potential for imaging of various inflammatory processes involving

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

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

    2009-04-15

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

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

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

  16. Erlotinib Versus Radiation Therapy for Brain Metastases in Patients With EGFR-Mutant Lung Adenocarcinoma

    Gerber, Naamit K.; Yamada, Yoshiya; Rimner, Andreas [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Shi, Weiji [Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Riely, Gregory J. [Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Beal, Kathryn [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Yu, Helena A. [Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Chan, Timothy A. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Zhang, Zhigang [Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Wu, Abraham J., E-mail: wua@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

    2014-06-01

    Purpose/Objectives: Radiation therapy (RT) is the principal modality in the treatment of patients with brain metastases (BM). However, given the activity of EGFR tyrosine kinase inhibitors in the central nervous system, it is uncertain whether upfront brain RT is necessary for patients with EGFR-mutant lung adenocarcinoma with BM. Methods and Materials: Patients with EGFR-mutant lung adenocarcinoma and newly diagnosed BM were identified. Results: 222 patients were identified. Exclusion criteria included prior erlotinib use, presence of a de novo erlotinib resistance mutation, or incomplete data. Of the remaining 110 patients, 63 were treated with erlotinib, 32 with whole brain RT (WBRT), and 15 with stereotactic radiosurgery (SRS). The median overall survival (OS) for the whole cohort was 33 months. There was no significant difference in OS between the WBRT and erlotinib groups (median, 35 vs 26 months; P=.62), whereas patients treated with SRS had a longer OS than did those in the erlotinib group (median, 64 months; P=.004). The median time to intracranial progression was 17 months. There was a longer time to intracranial progression in patients who received WBRT than in those who received erlotinib upfront (median, 24 vs 16 months, P=.04). Patients in the erlotinib or SRS group were more likely to experience intracranial failure as a component of first failure, whereas WBRT patients were more likely to experience failure outside the brain (P=.004). Conclusions: The survival of patients with EGFR-mutant adenocarcinoma with BM is notably long, whether they receive upfront erlotinib or brain RT. We observed longer intracranial control with WBRT, even though the WBRT patients had a higher burden of intracranial disease. Despite the equivalent survival between the WBRT and erlotinib group, this study underscores the role of WBRT in producing durable intracranial control in comparison with a targeted biologic agent with known central nervous system activity.

  17. Erlotinib Versus Radiation Therapy for Brain Metastases in Patients With EGFR-Mutant Lung Adenocarcinoma

    Purpose/Objectives: Radiation therapy (RT) is the principal modality in the treatment of patients with brain metastases (BM). However, given the activity of EGFR tyrosine kinase inhibitors in the central nervous system, it is uncertain whether upfront brain RT is necessary for patients with EGFR-mutant lung adenocarcinoma with BM. Methods and Materials: Patients with EGFR-mutant lung adenocarcinoma and newly diagnosed BM were identified. Results: 222 patients were identified. Exclusion criteria included prior erlotinib use, presence of a de novo erlotinib resistance mutation, or incomplete data. Of the remaining 110 patients, 63 were treated with erlotinib, 32 with whole brain RT (WBRT), and 15 with stereotactic radiosurgery (SRS). The median overall survival (OS) for the whole cohort was 33 months. There was no significant difference in OS between the WBRT and erlotinib groups (median, 35 vs 26 months; P=.62), whereas patients treated with SRS had a longer OS than did those in the erlotinib group (median, 64 months; P=.004). The median time to intracranial progression was 17 months. There was a longer time to intracranial progression in patients who received WBRT than in those who received erlotinib upfront (median, 24 vs 16 months, P=.04). Patients in the erlotinib or SRS group were more likely to experience intracranial failure as a component of first failure, whereas WBRT patients were more likely to experience failure outside the brain (P=.004). Conclusions: The survival of patients with EGFR-mutant adenocarcinoma with BM is notably long, whether they receive upfront erlotinib or brain RT. We observed longer intracranial control with WBRT, even though the WBRT patients had a higher burden of intracranial disease. Despite the equivalent survival between the WBRT and erlotinib group, this study underscores the role of WBRT in producing durable intracranial control in comparison with a targeted biologic agent with known central nervous system activity

  18. [11C]quinidine and [11C]laniquidar PET imaging in a chronic rodent epilepsy model: Impact of epilepsy and drug-responsiveness

    Introduction: To analyse the impact of both epilepsy and pharmacological modulation of P-glycoprotein on brain uptake and kinetics of positron emission tomography (PET) radiotracers [11C]quinidine and [11C]laniquidar. Methods: Metabolism and brain kinetics of both [11C]quinidine and [11C]laniquidar were assessed in naive rats, electrode-implanted control rats, and rats with spontaneous recurrent seizures. The latter group was further classified according to their response to the antiepileptic drug phenobarbital into “responders” and “non-responders”. Additional experiments were performed following pre-treatment with the P-glycoprotein modulator tariquidar. Results: [11C]quinidine was metabolized rapidly, whereas [11C]laniquidar was more stable. Brain concentrations of both radiotracers remained at relatively low levels at baseline conditions. Tariquidar pre-treatment resulted in significant increases of [11C]quinidine and [11C]laniquidar brain concentrations. In the epileptic subgroup “non-responders”, brain uptake of [11C]quinidine in selected brain regions reached higher levels than in electrode-implanted control rats. However, the relative response to tariquidar did not differ between groups with full blockade of P-glycoprotein by 15 mg/kg of tariquidar. For [11C]laniquidar differences between epileptic and control animals were only evident at baseline conditions but not after tariquidar pretreatment. Conclusions: We confirmed that both [11C]quinidine and [11C]laniquidar are P-glycoprotein substrates. At full P-gp blockade, tariquidar pre-treatment only demonstrated slight differences for [11C]quinidine between drug-resistant and drug-sensitive animals

  19. Development of a 11C-labeled tetrazine for rapid tetrazine–trans-cyclooctene ligation

    Herth, Matthias Manfred; Andersen, Valdemar L.; Lehel, Szabolcs;

    2013-01-01

    Tetrazine–trans-cyclooctene ligations are remarkably fast and selective reactions even at low micro-molar concentrations. In bioorthogonal radiochemistry, tools that enable conjugation of radioactive probes to pre-targeted vectors are of great interest. Herein, we describe the successful developm......Tetrazine–trans-cyclooctene ligations are remarkably fast and selective reactions even at low micro-molar concentrations. In bioorthogonal radiochemistry, tools that enable conjugation of radioactive probes to pre-targeted vectors are of great interest. Herein, we describe the successful...

  20. Comparison of the binding of the irreversible monoamine oxidase tracers, [{sup 11}C]clorgyline and [{sup 11}C]l-deprenyl in brain and peripheral organs in humans

    Fowler, Joanna S. E-mail: fowler@bnl.gov; Logan, Jean; Wang, Gene-Jack; Volkow, Nora D.; Telang, Frank; Ding Yushin; Shea, Colleen; Garza, Victor; Xu Youwen; Li Zizhong; Alexoff, David; Vaska, Paul; Ferrieri, Richard; Schlyer, David; Zhu Wei; John Gatley, S

    2004-04-01

    The monoamine oxidase A and B (MAO A and B) radiotracers [{sup 11}C]clorgyline (CLG) and [{sup 11}C]L-deprenyl (DEP) and their deuterium labeled counterparts (CLG-D and DEP-D) were compared to determine whether their distribution and kinetics in humans are consistent with their physical, chemical and pharmacological properties and the reported ratios of MAO A:MAO B in post-mortem human tissues. Irreversible binding was consistently higher for DEP in brain, heart, kidneys and spleen but not lung where CLG >DEP and not in thyroid where there is no DEP binding. The generally higher DEP binding is consistent with its higher enzyme affinity and larger free fraction in plasma while differences in regional distribution for CLG and DEP in brain, heart, thyroid and lungs are consistent with different relative ratios of MAO A and B in humans.

  1. Improved automated synthesis and preliminary animal PET/CT imaging of 11C-acetate

    To study a simple and rapid automated synthetic technology of 11C-acetate (11C- AC), automated synthesis of 11C-AC was performed by carboxylation of MeMgBr/tetrahydrofuran (THF) on a polyethylene loop with 11C-CO2, followed by hydrolysis and purification on solid-phase extraction cartridges using a 11C-Choline/Methionine synthesizer made in China. A high and reproducible radiochemical yield of above 40% (decay corrected) was obtained within the whole synthesis time about 8 min from 11C-CO2. The radiochemical purity of 11C-AC was over 95%. The novel, simple and rapid on-column hydrolysis-purification procedure should adaptable to the fully automated synthesis of 11C-AC at several commercial synthesis module. 11C-AC injection produced by the automated procedure is safe and effective, and can be used for PET imaging of animals and humans. (authors)

  2. Synthesis of [11C]salicylic acid and related compounds and their biodistribution in mice

    For in vivo measurement of the hydroxyl radical (%s·OH), we synthesized [11C]salicylic acid, [11C]O-acetylsalicylic acid and [11C]2-methoxybenzoic acid by carboxylation of 2-bromomagnesiumanisol using [11C]CO2. The radiochemical yield of [11C]salicylic acid, [11C]O-acetylsalicylic acid and [11C]2-methoxybenzoic acid calculated from trapped [11C]CO2 in a liquid argon cooled stainless tube was 7.3±1.6, 5.2 and 10.2±1.7% (decay corrected), respectively. The uptake of 11C tracers by mouse brain was 0.46, 0.32 and 0.46% dose/g tissue, respectively, at 10 min post injection and presented washout patterns thereafter

  3. Clinical aspects and perspectives of erlotinib in the treatment of patients with biliary tract cancer

    Jensen, Lars Henrik

    2016-01-01

    . The epidermal growth factor receptor system is upregulated in many cancers and can be targeted by the protein kinase inhibitor erlotinib. Erlotinib has demonstrated a clinically applicable effect in pancreatic and lung cancer Areas covered: In this review, the author presents the published clinical...... erlotinib was negative, but suggested improved progression free survival in cholangiocarcinoma patients when added to gemcitabine and oxaliplatin. There is no clinical, radiological or molecular marker to guide therapy, but genomic profiling and basket or umbrella trials may be useful in identifying the...

  4. Erlotinib for the treatment of relapsed non-small cell lung cancer.

    McLeod, C; Bagust, A; Boland, A; Hockenhull, J; Dundar, Y; Proudlove, C; Davis, H; Green, J; Macbeth, F; Stevenson, J; Walley, T; Dickson, R

    2009-06-01

    This paper presents a summary of the evidence review group (ERG) report into the clinical and cost-effectiveness of erlotinib for the treatment of relapsed non-small cell lung cancer (NSCLC), according to its licensed indication, based upon the evidence submission from Roche Products to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal (STA) process. The submitted clinical evidence includes one randomised controlled trial (RCT) (BR21) investigating the effect of erlotinib versus placebo, which demonstrates that erlotinib significantly increases median overall survival, progression-free survival and response rate compared with placebo. The majority of patients in the trial experienced non-haematological drug-related adverse effects. Currently there are no trials that directly compare erlotinib with any other second-line chemotherapy agent. For the purposes of indirect comparison, the manufacturer's submission provides a narrative discussion of data from 11 RCTs investigating the use of docetaxel. From these data the manufacturer concludes that erlotinib has similar clinical efficacy levels to docetaxel but results in fewer serious haematological adverse events; however, it is difficult to compare the results of BR21 with those of the docetaxel trials or with current UK clinical practice because, for example, the BR21 patient population is younger than that expected to present in UK clinical practice and almost half of the BR21 participants received erlotinib as third-line chemotherapy, with third-line chemotherapy being rare in the UK. The manufacturer's submission included a three-state model comparing erlotinib with docetaxel, reporting an incremental cost-effectiveness ratio (ICER) of 1764 pounds per quality-adjusted life-year (QALY) gained for erlotinib compared with docetaxel. Rerunning the manufacturer's economic model with varied parameters and assumptions increases the ICER to in excess of 52

  5. PET study using [11C]FTIMD with ultra-high specific activity to evaluate I2-imidazoline receptors binding in rat brains

    Introduction: We recently developed a selective 11C-labeled I2-imidazoline receptor (I2R) ligand, 2-(3-fluoro-4-[11C]tolyl)-4,5-dihydro-1H-imidazole ([11C]FTIMD). [11C]FTIMD showed specific binding to I2Rs in rat brains having a high density of I2R, as well as to I2Rs those in monkey brains, as illustrated by positron emission tomography (PET) and autoradiography. However, [11C]FTIMD also showed moderate non-specific binding in rat brains. In order to increase the specificity for I2R in rat brains, we synthesized [11C]FTIMD with ultra-high specific activity and evaluated its binding. Methods: [11C]FTIMD with ultra-high specific activity was prepared by a palladium-promoted cross-coupling reaction of the tributylstannyl precursor and [11C]methyl iodide, which was produced by iodination of [11C]methane using the single-pass method. Dynamic PET scans were conducted in rats, and the kinetic parameters were estimated. Results: [11C]FTIMD with ultra-high specific activity was successfully synthesized with an appropriate level of radioactivity and ultra-high specific activity (4470±1660 GBq/μmol at end of synthesis, n=11) for injection. In the PET study, distribution volume (VT) values in all the brain regions investigated whether I2R expression was greatly reduced in BU224-pretreatead rats compared with control rats (29–45% decrease). Differences in VT values between control and BU224-pretreated rats using [11C]FTIMD with ultra-high specific activity were greater than those using [11C]FTIMD with normal specific activity (17–34% decrease) in all brain regions investigated. Conclusion: Quantitative PET using [11C]FTIMD with ultra-high specific activity can contribute to the detection of small changes in I2R expression in the brain.

  6. Pharmacokinetic Analysis of 11C-PBR28 in the Rat Model of Herpes Encephalitis: Comparison with (R)-11C-PK11195.

    Parente, Andrea; Feltes, Paula Kopschina; Vállez García, David; Sijbesma, Jurgen W A; Moriguchi Jeckel, Cristina M; Dierckx, Rudi A J O; de Vries, Erik F J; Doorduin, Janine

    2016-05-01

    (11)C-PBR28 is a second-generation translocator protein (TSPO) tracer with characteristics supposedly superior to the most commonly used tracer for neuroinflammation, (R)-(11)C-PK11195. Despite its use in clinical research, no studies on the imaging properties and pharmacokinetic analysis of (11)C-PBR28 in rodent models of neuroinflammation have been published yet. Therefore, this study aimed to evaluate (11)C-PBR28 as a tool for detection and quantification of neuroinflammation in preclinical research and to compare its imaging properties with (R)-(11)C-PK11195. The herpes simplex encephalitis (HSE) model was used for induction of neuroinflammation in male Wistar rats. Six or 7 d after virus inoculation, a dynamic (11)C-PBR28 or (R)-(11)C-PK11195 PET scan with arterial blood sampling was obtained. Pharmacokinetic modeling was performed on the PET data and analyzed using volumes of interest and a voxel-based approach. Volume-of-interest- and voxel-based analysis of (11)C-PBR28 images showed overexpression of TSPO in brain regions known to be affected in the HSE rat model. (11)C-PBR28 was metabolized faster than (R)-(11)C-PK11195, with a metabolic half-life in plasma of 5 and 21 min, respectively. Overall, (11)C-PBR28 was more sensitive than (R)-(11)C-PK11195 in detecting neuroinflammation. The binding potential (BPND) of (11)C-PBR28 was significantly higher (P < 0.05) in the medulla (176%), pons (146%), midbrain (101%), hippocampus (85%), thalamus (73%), cerebellum (54%), and hypothalamus (49%) in HSE rats than in control rats, whereas (R)-(11)C-PK11195 showed a higher BPND only in the medulla (32%). The BPND in control animals was not significantly different between tracers, suggesting that the nonspecific binding of both tracers is similar. (11)C-PBR28 was more sensitive than (R)-(11)C-PK11195 in the detection of TSPO overexpression in the HSE rat model, because more brain regions with significantly increased tracer uptake could be found, irrespective of the data

  7. [11C]-metformin distribution in the liver and small intestine using dynamic PET in mice demonstrates tissue-specific transporter dependency

    Jensen, Jonas B; Sundelin, Elias I; Jakobsen, Steen;

    2016-01-01

    ) including Multidrug and Toxin Extrusion proteins (MATE) are essential for transport of metformin across membranes, but tissue-specific activity of these transporters in vivo is incompletely understood. Here, we use dynamic PET with C11-labelled metformin ([11C]-metformin) in mice to investigate the role of...

  8. Automated synthesis of [11C]choline, a positron-emitting tracer for tumor imaging

    (β-Hydroxyethyl)tri([11C]methyl)ammonium ([11C]choline) is a tracer very effective in imaging various human tumors using positron emission tomography (PET). We have constructed a computer-controlled [11C]choline synthetic apparatus which carries out the whole process of synthesis and product purification automatically. The setup is simple and the process quick. In 20 min, 11 GBq of [11C]choline (chloride) is obtainable from 26 GBq of [11C]CO2. The final product is a sterile and pyrogen-free [11C]choline 'injection'

  9. Binding kinetics of 11C-N-methyl piperidyl benzilate (11C-NMPB) in a rhesus monkey brain using the cerebellum as a reference region

    The binding kinetics of' 11C-N-methyl piperidyl benzilate (11C-NMPB) in rhesus monkey brain were studied using animal positron emission tomography (PET) (SHR2000). This study is intended to assess the validity of the method using the cerebellum as a reference region, and to evaluate the effects of anesthesia on 11C -NMPB binding. Two monkeys, anesthetized with ketamine, received intravenous 11C-NMPB alone (370-760 MBq, 11C-NMPB accumulated densely in the striatum and cerebral cortex with time. In contrast, the tracer accumulation significantly decreased with increased doses of nonradioactive NMPB. In the cerebellum, on the other hand, the accumulation of 11C-NMPB remained low and the tracer was slowly eliminated from the brain following the injection. 11C-NMPB binding in the cerebellum was barely affected by the increased dose of nonradioactive NMPB. We thus concluded that the specific 11C-NMPB binding was negligible in the cerebellum, and performed simplified evaluation of 11C-NMPB binding in each brain region by a graphical method using the cerebellum as a reference region. PET was conducted 26 times, in total both in ketamine-anesthetized and awake monkeys (n=3 each). Measurements of 11C-NMPB binding showed good run-to-run reproducibility within individual animals. When 11C-NMPB binding was compared between ketamine-treated and awake animals, a significant increase in 11C-NMPB binding was observed in the striatum but not in other brain regions of ketamine-treated animals. (author)

  10. A comparative small-animal PET evaluation of [{sup 11}C]tariquidar, [{sup 11}C]elacridar and (R)-[{sup 11}C]verapamil for detection of P-glycoprotein-expressing murine breast cancer

    Wanek, Thomas; Kuntner, Claudia; Sauberer, Michael [AIT Austrian Institute of Technology GmbH, Health and Environment Department, Molecular Medicine, Seibersdorf (Austria); Bankstahl, Jens P.; Bankstahl, Marion; Loescher, Wolfgang [University of Veterinary Medicine Hannover, Department of Pharmacology, Toxicology and Pharmacy, Hannover (Germany); Stanek, Johann; Langer, Oliver [AIT Austrian Institute of Technology GmbH, Health and Environment Department, Molecular Medicine, Seibersdorf (Austria); Medical University of Vienna, Department of Clinical Pharmacology, Vienna (Austria); Mairinger, Severin [AIT Austrian Institute of Technology GmbH, Health and Environment Department, Molecular Medicine, Seibersdorf (Austria); Medical University of Vienna, Department of Clinical Pharmacology, Vienna (Austria); University of Vienna, Department of Medicinal Chemistry, Vienna (Austria); Strommer, Sabine; Wacheck, Volker; Mueller, Markus [Medical University of Vienna, Department of Clinical Pharmacology, Vienna (Austria); Erker, Thomas [University of Vienna, Department of Medicinal Chemistry, Vienna (Austria)

    2012-01-15

    One important mechanism for chemoresistance of tumours is overexpression of the adenosine triphosphate-binding cassette transporter P-glycoprotein (Pgp). Pgp reduces intracellular concentrations of chemotherapeutic drugs. The aim of this study was to compare the suitability of the radiolabelled Pgp inhibitors [{sup 11}C]tariquidar and [{sup 11}C]elacridar with the Pgp substrate radiotracer (R)-[{sup 11}C]verapamil for discriminating tumours expressing low and high levels of Pgp using small-animal PET imaging in a murine breast cancer model. Murine mammary carcinoma cells (EMT6) were continuously exposed to doxorubicin to generate a Pgp-overexpressing, doxorubicin-resistant cell line (EMT6AR1.0 cells). Both cell lines were subcutaneously injected into female athymic nude mice. One week after implantation, animals underwent PET scans with [{sup 11}C]tariquidar (n = 7), [{sup 11}C]elacridar (n = 6) and (R)-[{sup 11}C]verapamil (n = 7), before and after administration of unlabelled tariquidar (15 mg/kg). Pgp expression in tumour grafts was evaluated by Western blotting. [{sup 11}C]Tariquidar showed significantly higher retention in Pgp-overexpressing EMT6AR1.0 compared with EMT6 tumours: the mean {+-} SD areas under the time-activity curves in scan 1 from time 0 to 60 min (AUC{sub 0-60}) were 38.8 {+-} 2.2 min and 25.0 {+-} 5.3 min (p = 0.016, Wilcoxon matched pairs test). [{sup 11}C]Elacridar and (R)-[{sup 11}C]verapamil were not able to discriminate Pgp expression in tumour models. Following administration of unlabelled tariquidar, both EMT6Ar1.0 and EMT6 tumours showed increases in uptake of [{sup 11}C]tariquidar, [{sup 11}C]elacridar and (R)-[{sup 11}C]verapamil. Among the tested radiotracers, [{sup 11}C]tariquidar performed best in discriminating tumours expressing high and low levels of Pgp. Therefore [{sup 11}C]tariquidar merits further investigation as a PET tracer to assess Pgp expression levels in solid tumours. (orig.)