10 results on '"Aerts, Joël"'
Search Results
2. Fully automated preparation and conjugation of N-succinimidyl 4-[18F]fluorobenzoate ([18F]SFB) with RGD peptide using a GE FASTlab™ synthesizer.
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Thonon, David, Goblet, David, Goukens, Eve, Kaisin, Geoffroy, Paris, Jérôme, Aerts, Joël, Lignon, Steve, Franci, Xavier, Hustinx, Roland, Luxen, André, Paris, Jérôme, Aerts, Joël, and Luxen, André
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MOLECULAR biology , *BIOMOLECULES , *FLUOROBENZOIC acid , *POSITRON emission tomography , *RADIOCHEMISTRY , *ANTI-infective agents , *AUTOMATION , *COMPARATIVE studies , *PHYSICAL & theoretical chemistry , *FLUORINE isotopes , *HETEROCYCLIC compounds , *RESEARCH methodology , *MEDICAL cooperation , *MOLECULAR structure , *OLIGOPEPTIDES , *RADIOISOTOPES , *RESEARCH , *EVALUATION research , *EQUIPMENT & supplies - Abstract
Purpose: The aim of this work was to automate the radiosynthesis of [(18)F]SFB, a widely used reagent for the labeling of biomolecules with (18)F on a new generation commercial synthesis module (FASTLab™, GE Healthcare).Procedures: Two synthesis approaches were implemented on this module: the classical "two-pot radiosynthesis" and the more recently described "one-pot" method.Results: The "two-pot" approach affords [(18)F]SFB with a 42% decay-corrected yield in 57 min (n = 24) with a chemical purity sufficient to avoid an intermediate HPLC purification. The recently established "one-pot" method, afforded a product with a lower chemical purity, in the conditions used in this report. The lower d.c. yield obtained (32% (n = 15)) was related to the low (18)F labeling yields obtained in MeCN compared with DMSO. The subsequent conjugation step with a RGD (PRGD2) peptide was also successfully automated.Conclusions: The formulated [(18)F]FPRGD2 was obtained without any operator manipulation with a d.c. yield of 13% ± 3% (n = 13) in 130 min, a radiochemical purity >98% and a specific activity of 140 ± 40 TBq/mmol. [ABSTRACT FROM AUTHOR]- Published
- 2011
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3. Thrombolytic therapy based on fucoidan-functionalized polymer nanoparticles targeting P-selectin.
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Juenet, Maya, Aid-Launais, Rachida, Li, Bo, Berger, Alice, Aerts, Joël, Ollivier, Véronique, Nicoletti, Antonino, Letourneur, Didier, and Chauvierre, Cédric
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POLYMERIC nanocomposites , *TISSUE plasminogen activator , *THROMBOLYTIC therapy , *PLATELET aggregation inhibitors , *EMULSION polymerization , *NANOPARTICLE synthesis - Abstract
Injection of recombinant tissue plasminogen activator (rt-PA) is the standard drug treatment for thrombolysis. However, rt-PA shows risk of hemorrhages and limited efficiency even at high doses. Polysaccharide-poly(isobutylcyanoacrylate) nanoparticles functionalized with fucoidan and loaded with rt-PA were designed to accumulate on the thrombus. Fucoidan has a nanomolar affinity for the P-selectin expressed by activated platelets in the thrombus. Solid spherical fluorescent nanoparticles with a hydrodynamic diameter of 136 ± 4 nm were synthesized by redox radical emulsion polymerization. The clinical rt-PA formulation was successfully loaded by adsorption on aminated nanoparticles and able to be released in vitro . We validated the in vitro fibrinolytic activity and binding under flow to both recombinant P-selectin and activated platelet aggregates. The thrombolysis efficiency was demonstrated in a mouse model of venous thrombosis by monitoring the platelet density with intravital microscopy. This study supports the hypothesis that fucoidan-nanoparticles improve the rt-PA efficiency. This work establishes the proof-of-concept of fucoidan-based carriers for targeted thrombolysis. [ABSTRACT FROM AUTHOR]
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- 2018
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4. Enabling Efficient Positron Emission Tomography (PET) Imaging of Synaptic Vesicle Glycoprotein 2A (SV2A) with a Robust and One-Step Radiosynthesis of a Highly Potent 18F-Labeled Ligand ([18F]UCB-H).
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Warnier, Corentin, Lemaire, Christian, Becker, Guillaume, Zaragoza, Guillermo, Giacomelli, Fabrice, Aerts, Joël, Otabashi, Muhammad, Bahri, Mohamed Ali, Mercier, Joël, Plenevaux, Alain, and Luxen, André
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GLYCOPROTEINS , *LIGANDS (Biochemistry) , *SYNAPTIC vesicles , *POSITRON emission tomography , *IODONIUM salts , *ORGANIC synthesis - Abstract
We herein describe the straightforward synthesis of a stable pyridyl(4-methoxyphenyl)iodonium salt and its [18F] radiolabeling within a one-step, fully automated and cGMP compliant radiosynthesis of [18F]UCB-H ([18F]7), a PET tracer for the imaging of synaptic vesicle glycoprotein 2A (SV2A). Over the course of 1 year, 50 automated productions provided 34 ± 2% of injectable [18F]7 from up to 285 GBq (7.7 Ci) of [18F]fluoride in 50 min (uncorrected radiochemical yield, specific activity of 815 ± 185 GBq/μmol). The successful implementation of our synthetic strategy within routine, high-activity, and cGMP productions attests to its practicality and reliability for the production of large doses of [18F]7. In addition to enabling efficient and cost-effective clinical research on a range of neurological pathologies through the imaging of SV2A, this work further demonstrates the real value of iodonium salts for the cGMP 18F-PET tracer manufacturing industry, and their ability to fulfill practical and regulatory requirements in that field. [ABSTRACT FROM AUTHOR]
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- 2016
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5. Evaluation of an unshielded luminescence flow-through radio-HPLC detector for LC quality control and preparation of PET radiopharmaceuticals
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Thonon, David, Kaisin, Geoffroy, Henrottin, Jean, Aerts, Joël, Van Malderen, Hans, and Luxen, André
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RADIOPHARMACEUTICALS , *LUMINESCENCE , *HIGH performance liquid chromatography , *LIQUID chromatography-mass spectrometry , *POSITRON emission tomography , *SCINTILLATION counters - Abstract
Abstract: Radio-HPLC is an essential method to assess the purity of PET radiopharmaceuticals. The usual NaI scintillator radiodetector requires heavy, costly and cumbersome lead shielding. The luminescence LB 500 fLumo detector has been developed to tackle these drawbacks and achieve high sensitivity. The fLumo uses a photon counting detector combined with a flow-through cell modified with a solid melt-on scintillator only sensitive to the positron. This study demonstrates the usefulness of the fLumo for analysis and purification of PET radiopharmaceuticals. [Copyright &y& Elsevier]
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- 2013
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6. Fast and reliable method for the preparation of ortho- and para-[18F]fluorobenzyl halide derivatives: Key intermediates for the preparation of no-carrier-added PET aromatic radiopharmaceuticals
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Lemaire, Christian, Libert, Lionel, Plenevaux, Alain, Aerts, Joël, Franci, Xavier, and Luxen, André
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HALIDES , *INTERMEDIATES (Chemistry) , *RADIOPHARMACEUTICALS , *NUCLEOPHILIC substitution reactions , *BENZALDEHYDE , *SOLID phase extraction , *HALOGENATION , *TEMPERATURE effect - Abstract
Abstract: A fast and reliable method suitable for the automated preparation of (substituted) [18F]fluorobenzyl halides from several [18F]fluorobenzaldehydes was developed. Aromatic nucleophilic substitution of trimethylammonium benzaldehyde triflate and nitro precursors was realized with no-carrier-added [18F]fluoride. After labeling, fluorine-18 containing aldehydes were trapped on a Solid Phase Extraction (SPE) cartridge and the subsequent conversion into benzyl halide was directly realized, on-line, on the support. Reduction of the aldehydes (>95%) was near-quantitative with an aqueous solution of NaBH4. Halogenation was performed on the same support with different aqueous solutions of concentrated acid (HI, HBr, HCl). The conversion of benzyl alcohols into [18F]fluorobenzyl halides (X=Cl, Br, I) usually proceeded within 2min at high yields. The halogenation proceeded at room temperature, with the exception of the 2-[18F]fluoro-3-methoxybenzyl, 2- and 4-[18F]fluorobenzyl halides, which required the use of HBr/HOAc (33%). With this method, various [18F]fluorobenzyl chloride, bromide and iodide compounds were obtained with high radiochemical purities (>90%) and with overall radiochemical yields of 15–70%. The radiosynthesis was completed in 30 or 45min from EOB, starting from the ammonium or nitro precursor, respectively. By using the same solid support, 2- and 4-[18F]fluorobenzyl bromide and iodide derivatives were near-quantitatively converted (>95%) into the corresponding azido compounds (60°C, 5min). As the reduction and halogenation steps were performed on solid supports, automation of the whole synthesis was straightforward. [Copyright &y& Elsevier]
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- 2012
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7. Synthesis and hydrolytic stability of novel 3-[18F]fluoroethoxybis(1-methylethyl)silyl]propanamine-based prosthetic groups
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Balentova, Eva, Collet, Charlotte, Lamandé-Langle, Sandrine, Chrétien, Françoise, Thonon, David, Aerts, Joël, Lemaire, Christian, Luxen, André, and Chapleur, Yves
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HYDROLASES , *PROSTHETIC groups (Enzymes) , *FLUORINE , *INORGANIC synthesis , *SILICON , *RING formation (Chemistry) , *RADIOCHEMICAL analysis - Abstract
Abstract: Two new silicon-based prosthetic groups, derived from 3-[ethoxybis(1-methylethyl)silyl]propanamine, have been prepared in good yields. These silicon groups bearing an acid or an azide group were coupled to a model tripeptide (Leu-Gly-Gly) either through a classical amide bond formation or through “click chemistry” via the Huisgen cycloaddition. The radiolabelling with fluorine-18 by substitution of the ethoxy group at silicon has been carried out with success in 51–54% decay corrected radiochemical yields. Radiolabelled peptides were easily prepared by direct 18F-fluorination of the silicon-bearing tripeptide or by coupling the peptide with a radiolabelled silicon-based prosthetic group. Their stabilities in physiological medium were studied and proved poor. [Copyright &y& Elsevier]
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- 2011
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8. Controlled Memory Processes in Questionable Alzheimer's Disease: A View from Neuroimaging Research.
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Bastin, Christine, Kerrouche, Nacer, Lekeu, Françoise, Adam, Stéphane, Guillaume, Bénédicte, Lemaire, Christian, Aerts, Joël, d'Ydewalle, Géry, Collette, Fabienne, and Salmon, Eric
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MEMORY testing , *ALZHEIMER'S disease , *COGNITION disorders , *POSITRON emission tomography , *GLUCOSE , *BRAIN imaging - Abstract
Alzheimer's disease (AD) is characterized by a progressive loss of controlled cognitive processes, and neuroimaging studies at early stages of AD provide an opportunity to tease out the neural correlates of controlled processes. Accordingly, controlled and automatic memory performance was assessed with the Process Dissociation Procedure in 50 patients diagnosed with questionable Alzheimer's disease (QAD). The patients' brain glucose metabolism was measured using FDG-PET. After a follow-up period of 36 months, 27 patients had converted to AD, while 23 remained stable. Both groups showed a similar decrease in controlled memory processes but preserved automatic processes at entry into the study. Voxel-based cognitive and metabolic correlations showed that a decrease in controlled memory processes was preferentially correlated with lower activity in the dorsomedial prefrontal and posterior cingulate cortices in very early AD patients. In stable QAD patients, reduced controlled performance in verbal memory correlated with impaired activity in the left anterior hippocampal structure. The results demonstrate the central role of a medial frontal-posterior cingulate network for controlled processing of episodic memory in the early stages of AD. [ABSTRACT FROM AUTHOR]
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- 2010
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9. Are Spatial Memories Strengthened in the Human Hippocampus during Slow Wave Sleep?
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Peigneux, Philippe, Laureys, Steven, Fuchs, Sonia, Collette, Fabienne, Perrin, Fabien, Reggers, Jean, Phillips, Christophe, Degueldre, Christian, Del Fiore, Guy, Aerts, Joël, Luxen, André, and Maquet, Pierre
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HEMODYNAMICS , *HIPPOCAMPUS (Brain) , *LIMBIC system , *CEREBRAL cortex - Abstract
In rats, the firing sequences observed in hippocampal ensembles during spatial learning are replayed during subsequent sleep, suggesting a role for posttraining sleep periods in the offline processing of spatial memories. Here, using regional cerebral blood flow measurements, we show that, in humans, hippocampal areas that are activated during route learning in a virtual town are likewise activated during subsequent slow wave sleep. Most importantly, we found that the amount of hippocampal activity expressed during slow wave sleep positively correlates with the improvement of performance in route retrieval on the next day. These findings suggest that learning-dependent modulation in hippocampal activity during human sleep reflects the offline processing of recent episodic and spatial memory traces, which eventually leads to the plastic changes underlying the subsequent improvement in performance. [Copyright &y& Elsevier]
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- 2004
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10. Cerebral correlates of explicit sequence learning
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Destrebecqz, Arnaud, Peigneux, Philippe, Laureys, Steven, Degueldre, Christian, Del Fiore, Guy, Aerts, Joël, Luxen, André, van der Linden, Martial, Cleeremans, Axel, and Maquet, Pierre
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POSITRON emission tomography , *CEREBRAL circulation - Abstract
Using positron emission tomography (PET) and regional cerebral blood flow (rCBF) measurements, we investigated the cerebral correlates of consciousness in a sequence learning task through a novel application of the Process Dissociation Procedure, a behavioral paradigm that makes it possible to separately assess conscious and unconscious contributions to performance. Results show that the metabolic response in the anterior cingulate/mesial prefrontal cortex (ACC/MPFC) is exclusively and specifically correlated with the explicit component of performance during recollection of a learned sequence. This suggests a significant role for the ACC/MPFC in the explicit processing of sequential material. [Copyright &y& Elsevier]
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- 2003
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