References of "Lemaire, Christian"
     in
Bookmark and Share    
Peer Reviewed
See detailEnantioselective synthesis of 2-[18F]fluoro-L-Tyrosine by catalytic phase-transfer alkylation.
Lemaire, Christian ULg; Gillet, S.; Ooi, T. et al

in Journal of Labelled Compounds & Radiopharmaceuticals (2001), 44

Detailed reference viewed: 11 (4 ULg)
Full Text
Peer Reviewed
See detailModeling p-18FMPPF pet kinetics for the detremination of local 5-HT1A receptor concentration.
Costes, N.; Le Bars, D.; Merlet, I. et al

in Journal of Nuclear Medicine : Official Publication, Society of Nuclear Medicine (2001), 42(S1), 209

Detailed reference viewed: 3 (0 ULg)
Full Text
Peer Reviewed
See detailVoxel-based distribution of metabolic impairment in corticobasal degeneration
Garraux, Gaëtan ULg; Salmon, Eric ULg; Peigneux, Philippe ULg et al

in Movement Disorders (2000), 15(5), 894-904

This report emphasizes the precise topographic distribution of cerebral metabolic impairment in corticobasal degeneration (CBD) and the pathophysiological differences between CBD and progressive ... [more ▼]

This report emphasizes the precise topographic distribution of cerebral metabolic impairment in corticobasal degeneration (CBD) and the pathophysiological differences between CBD and progressive supranuclear palsy (PSP). Statistical parametric mapping (SPM96) analysis of 18FDG positron emission tomography (PET) data was performed in 22 patients with CBD compared with 46 healthy subjects (HS) and 21 patients with PSP who were studied at rest. A statistical threshold of p <0.001 was fixed, further corrected for multiple or independent comparisons (p <0.05). In comparison with HS, the metabolic impairment in CBD was asymmetrically distributed in the putamen, thalamus, precentral (Brodmann's area, BA 4), lateral premotor (BA 6/44) and supplementary motor areas (SMA, BA 6), dorsolateral prefrontal (8/9/46) cortex, and the anterior part of the inferior parietal lobe (BA 40) including the intraparietal sulcus (BA 7/40). A similar hypometabolic pattern was observed for most individual analyses. When PSP was compared with CBD, metabolic impairment predominated in the midbrain, anterior cingulate (BA 24/32), and orbitofrontal regions (BA 10). The reverse contrast showed more posterior involvement in CBD (BA 6 and 5/7/40) including SMA. Our data suggest that multiple components of neural networks related to both movement execution and production of skilled movements are functionally disturbed in CBD compared with both HS and PSP. [less ▲]

Detailed reference viewed: 27 (1 ULg)
Full Text
Peer Reviewed
See detail[(18)F]p-MPPF: A radiolabeled antagonist for the study of 5-HT(1A) receptors with PET
Plenevaux, Alain ULg; Lemaire, Christian ULg; Aerts, Joël ULg et al

in Nuclear Medicine & Biology (2000), 27(5), 467-71

This paper summarizes the present status of the researches conducted with [(18)F]4-(2'-methoxyphenyl)-1-[2'-[N-(2"-pyridinyl)-p-fluorobenzamido ]ethyl]-piperazine known as [(18)F]p-MPPF, a new 5-HT(1A ... [more ▼]

This paper summarizes the present status of the researches conducted with [(18)F]4-(2'-methoxyphenyl)-1-[2'-[N-(2"-pyridinyl)-p-fluorobenzamido ]ethyl]-piperazine known as [(18)F]p-MPPF, a new 5-HT(1A) antagonist for the study of the serotonergic neurotransmission with positron emission tomography (PET). This includes chemistry, radiochemistry, animal data (rats, cats, and monkeys) with autoradiography and PET, human data with PET, toxicity, and metabolism. [less ▲]

Detailed reference viewed: 166 (37 ULg)
See detailSynthèse du 6-fluoro-a-méthyl-L-tryptophane et de ses principaux métabolites
Lambin, D.; Tadino, V.; Olynyk, Ch et al

Poster (2000, May 12)

Detailed reference viewed: 10 (0 ULg)
Peer Reviewed
See detailVoxel-based analysis of confounding effects of age and dementia severity on cerebral metabolism in Alzheimer's disease
Salmon, Eric ULg; Collette, Fabienne ULg; Degueldre, Christian ULg et al

in Human brain mapping (2000), 10(1), 39-48

Alzheimer's disease is characterized by early hippocampal lesions, but neuropathological and functional imaging studies have also demonstrated involvement of associative cortices in patients suffering ... [more ▼]

Alzheimer's disease is characterized by early hippocampal lesions, but neuropathological and functional imaging studies have also demonstrated involvement of associative cortices in patients suffering from this illness. New image-processing technologies have led to demonstration of predominant posteromedial cortical metabolic impairment in the disease. Confounding effects of both age and dementia severity on brain metabolism were assessed using categorical and correlational analyses performed with Statistical Parametric Mapping. Posterior cingulate and precuneus metabolism, assessed by positron emission tomography, was significantly correlated with age in a population of 46 patients with probable Alzheimer's disease. Metabolism in posterior cingulate and precuneus was higher in elderly than in younger patients with a diagnosis of Alzheimer's disease, even when dementia severity was taken as a confounding covariate. The data suggest that the sensitivity of positron emission tomography for the diagnosis of Alzheimer's disease is reduced in elderly cases, where less severe pathology is sufficient to induce clinical symptoms of dementia. Conversely, higher posteromedial metabolic impairment in early onset cases may reflect greater density of regional cerebral lesions or major decrease of functional afferences in a richly connected multimodal associative area. Posterior cingulate metabolism was also correlated to dementia severity, even when age was taken as a confounding covariate, whereas metabolism in the hippocampal formation was not shown to correlate with global cognitive deficit. Functional correlation was maintained between posterior cingulate and middle frontal cortex in demented patients as in elderly controls. The key role of posteromedial cortex in cognitive dysfunction assessed in Alzheimer's disease is probably related to its highly integrated position within attentional, visuospatial and memory neuronal networks. [less ▲]

Detailed reference viewed: 32 (1 ULg)
Full Text
Peer Reviewed
See detailTissue distribution, autoradiography, and metabolism of 4-(2'-methoxyphenyl)-1-[2' -[N-2"-pyridinyl)-p-[(18)F]fluorobenzamido]ethyl]piperazine (p-[(18)F]MPPF), a new serotonin 5-HT(1A) antagonist for positron emission tomography: An In vivo study in rats.
Plenevaux, Alain ULg; Weissmann, D.; Aerts, Joël ULg et al

in Journal of Neurochemistry (2000), 75(2), 803-11

The in vivo behavior of 4-(2'-methoxyphenyl)-1-[2'-[N-(2"-pyridinyl)-p-[(18)F]fluorobenzamido ]ethyl]-piperazine (p-[(18)F]MPPF), a new serotonin 5-HT(1A) antagonist, was studied in awake, freely moving ... [more ▼]

The in vivo behavior of 4-(2'-methoxyphenyl)-1-[2'-[N-(2"-pyridinyl)-p-[(18)F]fluorobenzamido ]ethyl]-piperazine (p-[(18)F]MPPF), a new serotonin 5-HT(1A) antagonist, was studied in awake, freely moving rats. Biodistribution studies showed that the carbon-fluorine bond was stable in vivo, that this compound was able to cross the blood-brain barrier, and that a general diffusion equilibrium could account for the availability of the tracer. The great quantity of highly polar metabolites found in plasma did not contribute to the small amounts of metabolites found in hippocampus, frontal cortex, and cerebellum. Exvivo p-[(18)F]MPPF and in vitro 8-hydroxy-2-(di-n-[(3)H]propylamino)tetralin autoradiography were compared both qualitatively and quantitatively. Qualitative evaluation proved that the same brain regions were labeled and that the p-[(18)F]MPPF labeling is (a) in total agreement with the known distribution of 5-HT(1A) receptors in rats and (b) characterized by very low nonspecific binding. Quantitative comparison demonstrated that the in vivo labeling pattern obtained with p-[(18)F]MPPF cannot be explained by differences in regional blood flow, capillary density, or permeability. The 5-HT(1A) specificity of p-[(18)F]MPPF and binding reversibility were confirmed in vivo with displacement experiments. Thus, this compound can be used to evaluate parameters characterizing 5-HT(1A) binding sites in the brain. [less ▲]

Detailed reference viewed: 54 (11 ULg)
Full Text
Peer Reviewed
See detailMedial temporal lobe metabolic impairment in dementia associated with motor neuron disease
Garraux, Gaëtan ULg; Salmon, Eric ULg; Degueldre, Christian ULg et al

in Journal of the Neurological Sciences (1999), 168(2), 145-150

In the course of their disease certain patients with frontotemporal dementia (FTD) develop clinical features compatible with a motor neuron disease (FTD-MND). Previous reports have suggested that the ... [more ▼]

In the course of their disease certain patients with frontotemporal dementia (FTD) develop clinical features compatible with a motor neuron disease (FTD-MND). Previous reports have suggested that the functional pattern is similar in FTD and FTD-MND. However, some neuropathological studies suggest greater involvement of medial temporal regions in FTD-MND than in FTD. Using statistical parametric mapping (SPM96), we compared the metabolic patterns obtained at rest with positron emission tomography in 10 FTD patients and three FTD-MND patients with those obtained from 46 healthy subjects (HS). Mean age, duration of illness and dementia stage did not differ statistically between the FTD and FTD-MND groups. In comparison with HS, both groups showed frontal and anterior temporal hypometabolism at P<0.001. When the FTD-MND group was compared to the FTD group, significant hypometabolism was only observed in bilateral amygdala, bilateral hippocampus, and bilateral enthorinal and parahippocampal regions (Brodmann's areas, BA 28/36) at P<0.005. We found no significant differences in regional glucose uptake when FTD patients were contrasted to FTD-MND patients. Our results suggest statistically comparable frontal and lateral temporal hypometabolism in both conditions but greater impairment of medial temporal lobe activity in FTD-MND. Our results and a review of the literature support the hypothesis that there is a functional continuum between classical motor neuron disease (cMND), FTD-MND, and FTD. [less ▲]

Detailed reference viewed: 18 (1 ULg)
Full Text
Peer Reviewed
See detailComparison of impaired subcortico-frontal metabolic networks in normal aging, subcortico-frontal dementia, and cortical frontal demential
Garraux, Gaëtan ULg; Salmon, Eric ULg; Degueldre, Christian ULg et al

in Neuroimage (1999), 10(2), 149-162

Normal aging, progressive supranuclear palsy (PSP), and frontotemporal dementia (FTD) are characterized by different degrees of decline in frontal lobe functions. We used (18)FDG-PET and statistical ... [more ▼]

Normal aging, progressive supranuclear palsy (PSP), and frontotemporal dementia (FTD) are characterized by different degrees of decline in frontal lobe functions. We used (18)FDG-PET and statistical parametric mapping (SPM96) to compare relative subcorticofrontal metabolic impairment at rest in 21 healthy elderly subjects (HES), 20 PSP patients, and 6 FTD patients. When HES were compared to 22 healthy young subjects, widespread decrease in metabolism was observed in bilateral medial prefrontal areas including anterior cingulate cortices, in dorsolateral prefrontal areas, in left lateral premotor area, in Broca's area, and in left insula. In PSP compared to the 43 healthy subjects (HS), we observed subcorticofrontal metabolic impairment including both motor and cognitive neural networks. Impairment of functional connections between midbrain tegmentum and cerebellar, temporal and pallidal regions was demonstrated in PSP as compared to HS. When comparing FTD to HS, glucose uptake was primarily reduced in dorsolateral and ventrolateral prefrontal cortices and in frontopolar and anterior cingulate regions. There was also bilateral anterior temporal, right inferior parietal, and bilateral striatal hypometabolism. Finally, FTD showed more severe striatofrontal metabolic impairment than PSP, while mesencephalothalamic involvement was only observed in PSP. Our data suggest that subcorticofrontal metabolic impairment is distributed in distinct subcorticocortical networks in normal aging, PSP, and FTD. Subcorticofrontal dementia in PSP is related to hypometabolism in discrete frontal areas, which are probably disconnected from certain subcortical structures. The concept of subcortical dementia is reinforced by our data, which show disrupted functional connections between mesencephalon and cerebellar cortex, inferior and medial temporal regions, and pallidum. [less ▲]

Detailed reference viewed: 12 (1 ULg)
See detailSynthèse du 6-fluoro-a-méthyl-L-tryptophane et d'un de ses métabolites
Lambin, D.; Tadino, V.; Olynyk, Ch et al

Poster (1999, May 03)

Detailed reference viewed: 10 (0 ULg)
Full Text
Peer Reviewed
See detailFluorodopa uptake and glucose metabolism in early stages of corticobasal degeneration.
Laureys, Steven ULg; Salmon, Eric ULg; Garraux, Gaëtan ULg et al

in Journal of Neurology (1999), 246(12), 1151-8

Fluorodopa (FDOPA) and fluorodeoxyglucose (FDG) PET was performed in six patients in early stages of corticobasal degeneration (CBD) and compared to Parkinson's disease (PD) patients with a similar degree ... [more ▼]

Fluorodopa (FDOPA) and fluorodeoxyglucose (FDG) PET was performed in six patients in early stages of corticobasal degeneration (CBD) and compared to Parkinson's disease (PD) patients with a similar degree of bradykinesia and rigidity and to healthy controls. Statistical parametric mapping analysis comparing CBD to controls showed metabolic decrease in premotor, primary motor, supplementary motor, primary sensory, prefrontal, and parietal associative cortices, and in caudate and thalamus contralateral to the side of clinical signs. Except for the prefrontal regions a similar metabolic pattern was observed when CBD was compared to PD. Putamen FDOPA uptake was decreased in both CBD and PD. Caudate FDOPA uptake in CBD patients was decreased contralateral to clinical signs when compared to controls, but was higher than in PD. In early stages of CBD, FDOPA and FDG PET patterns differed from those observed in PD. In CBD the asymmetry in FDOPA uptake was less pronounced than that of clinical signs or metabolic impairment. [less ▲]

Detailed reference viewed: 33 (1 ULg)
Full Text
Peer Reviewed
See detailCerebral metabolism during vegetative state and after recovery to consciousness
Laureys, Steven ULg; Lemaire, Christian ULg; Maquet, Pierre ULg et al

in Journal of Neurology, Neurosurgery & Psychiatry (1999), 67(1), 121-122

Detailed reference viewed: 11 (0 ULg)
Full Text
Peer Reviewed
See detail5-HT1A Receptors visualization with p-[18F]MPPF in healthy volunteers.
Plenevaux, Alain ULg; Lemaire, Christian ULg; Salmon, Eric ULg et al

in Journal of Labelled Compounds & Radiopharmaceuticals (1999), 42

Detailed reference viewed: 11 (2 ULg)
Peer Reviewed
See detailp-[18F]MPPF, a fluoro analog of WAY-100635 for visualisation of 5-HT1A receptors in cat.
Le Bars, D.; Ginovart, N.; Hassoun, W. et al

in Journal of Labelled Compounds & Radiopharmaceuticals (1999), 42

Detailed reference viewed: 8 (2 ULg)
Peer Reviewed
See detailThe synthesis of 6-[18F]fluoro-L-dopa by chiral catalytic phase-transfer alkylation.
Lemaire, Christian ULg; Guillouet, S.; Plenevaux, Alain ULg et al

in Journal of Labelled Compounds & Radiopharmaceuticals (1999), 42

Detailed reference viewed: 13 (1 ULg)
Peer Reviewed
See detailIn vivo studies of p-[18F]MPPF metabolites in human.
Damhaut, Ph.; Plenevaux, Alain ULg; Lemaire, Christian ULg et al

in Journal of Labelled Compounds & Radiopharmaceuticals (1999), 42

Detailed reference viewed: 5 (2 ULg)
Peer Reviewed
See detail5-HT1A receptor distribution in the human brain: preliminary PET data with p-[18F]MPPF.
Fuchs, Sonia ULg; Plenevaux, Alain ULg; Degueldre, Christian ULg et al

in Society for Neuroscience / Abstracts (1999), 25

Detailed reference viewed: 10 (0 ULg)
Full Text
Peer Reviewed
See detailp-[18F]MPPF, 5-HT1A antagonist: comparison to [3H]8-OH-DPAT with autoradiography
Plenevaux, Alain ULg; Weissmann, D.; Lemaire, Christian ULg et al

in Society for Neuroscience / Abstracts (1999)

p-MPPF 4-(2’-methoxyphenyl)-1-[2’-[N-(2’’-pyridinyl)-p-fluorobenzamido] ethyl]piperazine is the para-fluorobenzoyl analog of the highly selective 5-HT1A antagonist WAY-100635. The one step procedure used ... [more ▼]

p-MPPF 4-(2’-methoxyphenyl)-1-[2’-[N-(2’’-pyridinyl)-p-fluorobenzamido] ethyl]piperazine is the para-fluorobenzoyl analog of the highly selective 5-HT1A antagonist WAY-100635. The one step procedure used to label p-MPPF with fluorine-18 (cyclotron produced positron emitter of 110 min half-life) leads to a radiopharmaceutical compound easily prepared on a large scale. The preliminary evaluations conducted in rats and cats are good reason to consider p-[18F]MPPF as an interesting reversible radioligand to study the 5-HT1A receptor family in humans with positron emission tomography (PET). In this paper we report a careful comparison between p-[18F]MPPF and [3H]8-OH-DPAT with autoradiography and quantitative densitometry in the same animal. All experiments were conducted in Sprague Dawley male rats. For p-[18F]MMPF, the results were obtained ex-vivo after an intravenous injection of high specific activity radioligand (0.8-1.5 Ci/µmol) in vigil (no anesthesia), free moving and unstressed animals. For the purpose, permanent cannulation of the posterior vena cava were realized at least four days in advance. The [3H]8-OH-DPAT results were obtained in vitro on adjacent coronal sections to the one used for the p-[18F]MPPF autoradiography. Quantitative densitometry was employed to compare the values obtained in relevant brain structures (frontal cortex, lateral septum, hippocampus, dorsal raphe, entorhinal cortex and cerebellum). The plot of the p-[18F]MPPF values obtained for each structure against the [3H]8-OH-DPAT results displayed a significant linear correlation. These results demonstrate that from a qualitative as well as quantitative point of view, the binding of p-[18F]MPPF is totally comparable to the one of [3H]8-OH-DPAT. Supported by grants from INSERM/CGRI and FNRS Belgium. [less ▲]

Detailed reference viewed: 29 (2 ULg)
Peer Reviewed
See detailSynthesis and in vivo evaluation of 6-fluoro-a-methyl-L-tryptophan.
Lambin, D.; Tadino, V.; Olynyk, C. et al

in American Chemical Society / Abstracts (1999)

Detailed reference viewed: 6 (2 ULg)
Full Text
Peer Reviewed
See detailSolid phase extraction : An alternative to the use of rotary evaporators for solvent removal in the rapid formulation of PET radiopharmaceuticals
Lemaire, Christian ULg; Plenevaux, Alain ULg; Aerts, Joël ULg et al

in Journal of Labelled Compounds & Radiopharmaceuticals (1999), 42(1), 63-75

Solid phase extraction (SPE) was used for the formulation of several radiopharmaceuticals. The method involves dilution of the previously purified HPLC compound with water, trapping of the activity on an ... [more ▼]

Solid phase extraction (SPE) was used for the formulation of several radiopharmaceuticals. The method involves dilution of the previously purified HPLC compound with water, trapping of the activity on an SPE bed, washing off the support, elution of the radiopharmaceutical with a small volume of ethanol (<1 mL) and dilution with sterile isotonic saline solution. Recovery of the radiopharmaceuticals was always higher than 97%. Two different methods of automation were developed for the formulation of [11C] and [18F]radiopharmaceuticals. In all cases, organic solvent levels in the injectable solution were below the recommended limits. This fast (3-6 min.) and easy to automate process can be considered as an alternative to the conventional methods (rotary evaporators). Copyright © 1999 John Wiley [less ▲]

Detailed reference viewed: 63 (6 ULg)