Design, synthèse et évaluation de contrastophores bimodaux pour l'imagerie par absorption à deux photons et par tomographie par émission de positons

The purpose of this subject has been the synthesis of a bimodal probe using TPA–PET techniques for a potential application in biological imaging.In this context, we have synthesized a new range of A–π –D fluorophores incorporating diazine (p-deficient heterocycle) as electron-withdrawing moiety, N,N-dimethylaniline as electron-donating part and fluorene as p-conjugated linker. In order to increase the conjugation along the scaffold, ethynyl and/or triazole bridges have been introduced on both sides of the fluorene. The UV/Vis and photoluminescence properties have been measured. Further to those results two-photon absorption cross-section of our fluorophores (dTPA) has been obtained. Following these promising results, hydrophilic compounds using PEG groups have been prepared and photoluminescence properties have been carried out. In order to use the boron center as a site for radiofluorination, the synthesis of "BODIPY-like" probes has been considered. A new series of pyrimidine and triazole ligand have been synthesized but the corresponding boron complexes haven’t been obtained.L’objectif de ce travail a porté sur l’élaboration d’une sonde bimodale ADP–TEP (absorption à deux photons–tomographie par emission de positons) pour des applications en imagerie médicale.Dans un premier temps, le projet a consisté en le design, la synthèse et l’évaluation des propriétés photophysiques d’une nouvelle série de chromophores diaziniques A–p–D (A : groupement électro-attracteur, p : lien conjugué, D : groupement électro-donneur). Des études de relation structure-propriétés photophysiques impliquant des modulations sur chacune des sous-structures (groupements A et D, lien p-conjugué) ont été réalisées puis étudiées en UV et en fluorescence. Suite à l’obtention de ces premiers résultats, des mesures d’absorption à deux photons ont été effectuées sur ces fluorophores.Dans un second temps, les fluorophores ont été modifiés afin de greffer des parties hydrophiles. Des propriétés photophysiques encourageantes ont été obtenues et des premiers tests en imagerie bi-photonique ont été réalisés.L’insertion du fluor radiomarqué est envisagée via l’insertion d’un groupement –BF2. Pour cela des structures chélatantes, « mimes de BODIPY », incorporant une pyrimidine ou un triazole ont été élaborées. Des premiers essais ont été conduits mais n’ont pas permis l’obtention des composés borés correspondants

Prediction of photophysical properties of pyrimidine chromophores using Taguchi method

International audienceThis paper presents the photophysical properties of a series of pyrimidine chromophores. The influence of three parameters has been studied: the nature of the electron-donating group and of the π-conjugated linker as well as the substituted position of the pyrimidine core (2, 4 and 6 position). Taguchi design of experiment combined with analysis of variance methodologies have been employed. This approach has permitted to highlight the main factor affecting the absorption and emission wavelengths of the studied compounds. Absorption maxima of this family of compounds can be predicted with relatively good precision (±18 nm). The emission maxima can be also predicted, however the precision is lower (±39 nm). Taguchi methodology has been also employed with these families of compounds to optimize the intramolecular charge transfer estimated by emission solvatochromy

Design, synthesis and evaluation of bimodal contrastophores for tow-photon microscopy and positron emission tomography

L’objectif de ce travail a porté sur l’élaboration d’une sonde bimodale ADP–TEP (absorption à deux photons–tomographie par emission de positons) pour des applications en imagerie médicale.Dans un premier temps, le projet a consisté en le design, la synthèse et l’évaluation des propriétés photophysiques d’une nouvelle série de chromophores diaziniques A–p–D (A : groupement électro-attracteur, p : lien conjugué, D : groupement électro-donneur). Des études de relation structure-propriétés photophysiques impliquant des modulations sur chacune des sous-structures (groupements A et D, lien p-conjugué) ont été réalisées puis étudiées en UV et en fluorescence. Suite à l’obtention de ces premiers résultats, des mesures d’absorption à deux photons ont été effectuées sur ces fluorophores.Dans un second temps, les fluorophores ont été modifiés afin de greffer des parties hydrophiles. Des propriétés photophysiques encourageantes ont été obtenues et des premiers tests en imagerie bi-photonique ont été réalisés.L’insertion du fluor radiomarqué est envisagée via l’insertion d’un groupement –BF2. Pour cela des structures chélatantes, « mimes de BODIPY », incorporant une pyrimidine ou un triazole ont été élaborées. Des premiers essais ont été conduits mais n’ont pas permis l’obtention des composés borés correspondants.The purpose of this subject has been the synthesis of a bimodal probe using TPA–PET techniques for a potential application in biological imaging.In this context, we have synthesized a new range of A–π –D fluorophores incorporating diazine (p-deficient heterocycle) as electron-withdrawing moiety, N,N-dimethylaniline as electron-donating part and fluorene as p-conjugated linker. In order to increase the conjugation along the scaffold, ethynyl and/or triazole bridges have been introduced on both sides of the fluorene. The UV/Vis and photoluminescence properties have been measured. Further to those results two-photon absorption cross-section of our fluorophores (dTPA) has been obtained. Following these promising results, hydrophilic compounds using PEG groups have been prepared and photoluminescence properties have been carried out. In order to use the boron center as a site for radiofluorination, the synthesis of "BODIPY-like" probes has been considered. A new series of pyrimidine and triazole ligand have been synthesized but the corresponding boron complexes haven’t been obtained

Revision of Mason's procedure (vertical banded gastroplasty) to Roux-en-Y gastric bypass: role of an associated fundectomy in weight loss outcomes

International audienceBACKGROUND: Vertical banded gastroplasty (VBG) presents a significant rate of long-term complications, and revisions are often necessary. Conversion to Roux-en-Y gastric bypass (RYGB) seems to be preferred, but literature data remain limited. OBJECTIVES: To analyze the indications, safety, results of conversions from VBG to RYGB, and to identify predictive factors of success or failure. SETTING: Two specialized centers of bariatric surgery. METHODS: This bicentric retrospective study included all the patients who benefited from a conversion from VBG to RYGB between 2008 and January 2020. Demographic characteristics, indications, preoperative workups, intraoperative data, complications, and weight loss results were analyzed. RESULTS: During the study period, 85 patients underwent a conversion to RYGB. The mean body mass index (BMI_ before conversion was 40.6 kg/m(2). 82.3% of the patients were converted because of weight loss failure and 17.6% because of a complication of their VBG. The global rate of complications was 25%. After an average follow-up of 35 months and a rate of loss to follow-up of 33%, the mean BMI was 33.5 kg/m. The weight loss success rate according to Reinhold's criteria was 64.7%, and resolution of complications was obtained in 89.1%. The association of a fundectomy was a predictive factor of weight loss (odds ratio, .27; P = .04), whereas primary failure of the VBG was a predictive factor of failure. CONCLUSION: Conversion from VBG to RYGB remains the procedure of choice to achieve satisfying weight loss and resolution of functional complications. The addition of a fundectomy appeared to have a significant positive impact on weight loss outcomes

Synthesis and Photophysical Properties of Push-Pull Structures Incorporating Di-azines as Attracting Part with a Fluorene Core

International audienc

Synthesis and Photophysical Properties of a Series of Pyrazine-Based Push-Pull Chromophores

International audienc