Kinetic analysis of [11C]befloxatone in the human brain, a selective radioligand to image monoamine oxidase A.

International audienceBACKGROUND: [11C]Befloxatone measures the density of the enzyme monoamine oxidase A (MAO-A) in the brain. MAO-A is responsible for the degradation of different neurotransmitters and is implicated in several neurologic and psychiatric illnesses. This study sought to estimate the distribution volume (VT) values of [11C]befloxatone in humans using an arterial input function. METHODS: Seven healthy volunteers were imaged with positron emission tomography (PET) after [11C]befloxatone injection. Kinetic analysis was performed using an arterial input function in association with compartmental modeling and with the Logan plot, multilinear analysis (MA1), and standard spectral analysis (SA) at both the regional and voxel level. Arterialized venous samples were drawn as an alternative and less invasive input function. RESULTS: An unconstrained two-compartment model reliably quantified VT values in large brain regions. A constrained model did not significantly improve VT identifiability. Similar VT results were obtained using SA; however, the Logan plot and MA1 slightly underestimated VT values (about -10 %). At the voxel level, SA showed a very small bias (+2 %) compared to compartmental modeling, Logan severely underestimated VT values, and voxel-wise images obtained with MA1 were too noisy to be reliably quantified. Arterialized venous blood samples did not provide a satisfactory alternative input function as the Logan-VT regional values were not comparable to those obtained with arterial sampling in all subjects. CONCLUSIONS: Binding of [11C]befloxatone to MAO-A can be quantified using an arterial input function and a two-compartment model or, in parametric images, with SA

Dopamine Transporter and Reward Anticipation in a Dimensional Perspective : A Multimodal Brain Imaging Study

We would like to thank Christine Baron, Vincent Brulon, Stéphane LeHelleix, Stéphane Demphel, Claude Comtat, Frédéric Dollé, Philippe Gervais, and Renaud Maroy from the Service Hospitalier Frédéric Joliot for their efficient technical support and 11C radioligand preparation. They thank Marie Prat, Audrey Pepin, and Audrey Mabondo for their help in PET processing and Pr. Maria-Joao Santiago-Ribeiro and Dr Renaud de Beaurepaire for their involvement in the recruitment of participants.Peer reviewedPostprin

Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign

Abstract: In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109 M ⊙. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87’s spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded

Effectiveness, Quality of Life, and Cost of Caring for Children in France with Recurrent Acute Rhinopharyngitis Managed by Homeopathic or Non-Homeopathic General Practitioners: A Pragmatic, Prospective Observational Study

Background & Objective: In France, non-homeopathic general practitioners (GPs) often use antibacterials to treat children with recurrent acute viral rhinopharyngitis; whereas homeopathic GPs tend to use homeopathic medicines. We compared the effectiveness, the quality of life of the parents, and the direct and indirect costs associated with treatment from homeopathic and non-homeopathic GPs. Method: We assessed the direct (consultations, medicines, further tests) and indirect (time off work) costs of the two types of treatment to society, the patient, and social security. We also assessed the effectiveness of the treatment received and the quality of life of the parents. Results: Of the 499 children included, 231 were treated by 62 non-homeopathic GPs and 268 by 73 homeopathic GPs. The effectiveness (assessed as complications/patient, total number of adverse events, and quality of life) [mean overall Parents of children with Ear, Nose, and Throat infections Quality of Life questionnaire(C) scale score] was better in the homeopathic GP group than in the non-homeopathic GP group. No significant difference was found between the two groups for the total costs to social security ( Conclusion: This study produced new findings that indicate that, in France, acute rhinopharyngitis is handled differently by homeopathic GPs and non-homeopathic GPs: homeopathic GPs prescribe fewer antibacterials than non-homeopathic GPs for the treatment of recurrent acute rhinopharyngitis in children aged between 18 months and 4 years. Moreover, homeopathic treatment gave better results in terms of pragmatic medical effectiveness (fewer episodes and fewer complications) and the parents' quality of life, with similar total medical costs to social security. However, this study is potentially biased by the lack of homogeneity of the two patient-samples in terms of theGeneral-practice, Health-economics, Homoeopathy, Nasopharyngitis, Quality-of-life

Lower midbrain dopamine transporter availability in depressed patients: Report from high-resolution PET imaging

International audienceBackground: A reduced presynaptic dopamine neurotransmission has long been implicated in major depressive disorder (MDD). However, molecular imaging studies that assessed the dopamine transporter (DAT) availability have led to inconsistent results, partly due to methodological considerations, and to exclusive focus on the striatum, precluding findings in extra-striatal regions.Methods: Herein, we leveraged our database of high-resolution Positron Emission Tomography (PET) images acquired with a highly selective radiotracer, [11C]PE2I, to assess striatal and extra-striatal DAT availability in eight patients treated for depression compared to twenty-four healthy controls.Results: Statistical parametric mapping and voxel-based analyses of PET images detected a significant lower DAT availability in depressed patients within the superior part of the midbrain (right, pFWE = 0.002; left, pFWE = 0.006), a region including the ventral tegmental area and the substantia nigra from where the mesocorticolimbic and nigrostriatal dopamine pathways originate. A similar difference was found in the right dorsal putamen (pFWE = 0.012).Limitations: The statistical power was limited to detect only large effects, due to the size of the patients' sample.Conclusions: The findings support the hypothesis that a reduced presynaptic dopamine function plays a role in the pathophysiology of depression, and that extra-striatal dopamine function should be further investigated

286. Dopamine Transporter and Reward Anticipation in Psychiatric Patients: A Positron Emission Tomography and Functional Magnetic Resonance Imaging Study

International audienc

Gestion agro-écologique de la flore adventice dans les systèmes à bas niveau d’usage d’herbicides : le projet ADVHERB

Séminaire organisé en janvier 2013 par le groupe Recherche EcophytoNational audienceReducing the reliance on chemicals for food production is a major challenge faced by agriculture today. Yet, current scientific knowledge does not provide generic alternatives to chemicals for weed management and the potential yield loss that could result from a lack of weed control. If we are to reduce the use of herbicides, are we today in a position to propose new cropping systems and landscape engineering at the scale of territories that would simultaneously deliver acceptable levels of weed control and sufficient crop yield and even provide additional environmental benefits such as the enhancement of biodiversity in agrosystems? These questions are being visited within an ANR-funded project «Towards an agro-ecological management of weeds in low herbicide systems» led by the UMR Agroécologie in Dijon and which is bringing together several national research partners.La réduction de la dépendance aux herbicides est un enjeu sociétal fort et d’actualité. Or, l’état actuel des connaissances ne fournit pas de solutions alternatives génériques pour gérer la flore adventice et ainsi minimiser les pertes potentielles de rendements. Dans le contexte d’une réduction de l’utilisation d’herbicides, peut-on envisager de nouveaux systèmes de culture et des nouveaux agencements spatio-temporels des territoires agricoles qui permettraient simultanément de gérer les adventices, de maintenir le caractère productif des cultures et, pourquoi pas, d’offrir une plus value environnementale en termes de services écologiques ou de maintien de la biodiversité ? Ces questions sont traitées dans le cadre du projet ANR Systerra ADVHERB « Gestion agro-écologique de la flore adventice dans des systèmes à bas niveaux d’herbicides » coordonné par l’UMR Agroécologie de Dijon et qui associe plusieurs partenaires nationaux