118 research outputs found

    Perinatal grief following neonatal comfort care for lethal fetal condition

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    BACKGROUND: The objective of the study was to assess perinatal grief experienced after continuing pregnancy and comfort care in women diagnosed with lethal fetal condition compared with termination of pregnancy for fetal anomaly (TOPFA). METHODS: This was a retrospective observational study which included women who chose to continue their pregnancy after the diagnosis of lethal fetal condition with comfort care support at birth at the Prenatal Diagnosis Center of Rennes Hospital from January 2007 to January 2017. Women were matched with controls who underwent TOPFA for the same type of fetal anomaly, gestational age at diagnosis and year. Women were evaluated by a questionnaire including the Perinatal Grief Scale. RESULTS: There were 28 patients in the continuing pregnancy group matched with 56 patients in the TOPFA group. Interval between fetal loss and completion of questionnaire was 6±3 years. Perinatal grief score was similar at 61±22 vs 58±18 (p = 0.729) in the continuing pregnancy and TOPFA groups, respectively. Women in the TOPFA group expressed more guilt. The cesarean-section rate in the continuing pregnancy group was 25% . CONCLUSION: Perinatal grief experienced by women opting for continuing pregnancy and comfort care after diagnosis of a potentially lethal fetal anomaly is not more severe than for those choosing TOPFA

    Live-Cell Chromosome Dynamics and Outcome of X Chromosome Pairing Events during ES Cell Differentiation

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    SummaryRandom X inactivation represents a paradigm for monoallelic gene regulation during early ES cell differentiation. In mice, the choice of X chromosome to inactivate in XX cells is ensured by monoallelic regulation of Xist RNA via its antisense transcription unit Tsix/Xite. Homologous pairing events have been proposed to underlie asymmetric Tsix expression, but direct evidence has been lacking owing to their dynamic and transient nature. Here we investigate the live-cell dynamics and outcome of Tsix pairing in differentiating mouse ES cells. We find an overall increase in genome dynamics including the Xics during early differentiation. During pairing, however, Xic loci show markedly reduced movements. Upon separation, Tsix expression becomes transiently monoallelic, providing a window of opportunity for monoallelic Xist upregulation. Our findings reveal the spatiotemporal choreography of the X chromosomes during early differentiation and indicate a direct role for pairing in facilitating symmetry-breaking and monoallelic regulation of Xist during random X inactivation

    Novel synthesis and characterisation of 3,3-dimethyl-50-(2-benzothiazolyl)- spironaphth(indoline-2,30-[3H]naphth[2,1-b] [1,4]oxazine) derivatives

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    Novel modified spirooxazines (SOs) with additional chelating groups were synthesised and the crystal structure of one of these was determined. UV–vis spectroscopic characterization of the photoisomerization of the SO derivatives shows that the photochromic behaviour is altered with Zn2+ coordination. In particular, addition of a group as in carboxylic acid 5 to the indole section of the SO increases the lifetime of the merocyanine Zn 2+ complex by 20-fold compared to the methylated indole 6

    Determination of the mechanism of action of diazepinones targeting melanoma

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    Le mĂ©lanome est la forme de cancer de la peau la plus meurtriĂšre. Cette agressivitĂ© est due Ă  sa forte tendance Ă  mĂ©tastaser, entraĂźnant un mauvais pronostic. MalgrĂ© l’introduction en 2011 de stratĂ©gies thĂ©rapeutiques innovantes (inhibiteurs de kinases et immunothĂ©rapies), les patients font toujours face Ă  des rĂ©sistances innĂ©es ou acquises et ces nouveaux traitements n’offrent qu’une amĂ©lioration partielle et temporaire. En raison d'une incidence globale dans le monde en perpĂ©tuelle augmentation, le dĂ©veloppement de nouveaux mĂ©dicaments et de nouvelles combinaisons thĂ©rapeutiques agissant contre le mĂ©lanome mĂ©tastatique (MM) est un dĂ©fi de santĂ© publique majeur.Le JMV5038, une pyrido-imidazo[1,3]diazĂ©pinone produite par l’équipe, avait montrĂ© lors d’un criblage sur le panel de 60 lignĂ©es cellulaires cancĂ©reuses du National Cancer Institute, une activitĂ© particuliĂšrement intĂ©ressante (GI50 de l’ordre du micromolaire) sur plusieurs lignĂ©es. Ces rĂ©sultats ont Ă©tĂ© confirmĂ©s au sein de notre institut sur plusieurs lignĂ©es de mĂ©lanome malin humain (MDA-MB-43, A375). L’objectif de cette thĂšse Ă©tait de prĂ©ciser, par des Ă©tudes in vitro utilisant comme modĂšles cellulaires 3 lignĂ©es humaines de mĂ©lanome malin (A375, MDA-MB-435, B16F10), le mĂ©canisme d’action (MOA) du JMV5038. Notre stratĂ©gie expĂ©rimentale s’articulait autour de trois objectifs : (a) dĂ©terminer la localisation intracellulaire du JMV5038, (b) dĂ©velopper des outils afin d'identifier sa ou ses cibles pharmacologiques et (c) prĂ©ciser son mĂ©canisme d’action molĂ©culaire. L’imagerie Raman s’est avĂ©rĂ©e la technique la plus adaptĂ©e pour dĂ©terminer la localisation/distribution du JMV5038, une petite molĂ©cule active et non intrinsĂšquement fluorescente. Une accumulation du JMV5038 au niveau de l’espace pĂ©ri-membranaire des cellules de mĂ©lanome a ainsi pu ĂȘtre mise en Ă©vidence. Nous avons dĂ©veloppĂ© Ă  partir du JMV5038 des prĂ©-sondes qui permettront d’identifier la ou les cibles pharmacologiques du JMV5038 in cellulo, par une approche de protĂ©omique-chimique basĂ©e sur la chimie-click. Ce dĂ©veloppement chimique nous a aussi donnĂ© des informations prĂ©cieuses quant aux relations structure activitĂ© (RSA) des diazĂ©pinones. Enfin, les Ă©tudes fonctionnelles nous ont permis de progresser significativement dans la comprĂ©hension du MOA du JMV5038. En effet, nous avons montrĂ© que l’activitĂ© antitumorale du JMV5038 est associĂ©e Ă  une inhibition indirecte et atypique de la protĂ©ine Chk1, classiquement impliquĂ©e dans la voie de rĂ©ponses aux dommages Ă  l’ADN. Cette inhibition est due Ă  une augmentation de la phosphorylation en S280 de Chk1, entraĂźnant une modification de sa localisation (accumulation cytoplasmique) et donc potentiellement une inhibition de son activitĂ©. Ce dĂ©faut dans l’axe ATR/Chk1 entraine alors une sensibilisation des cellules cancĂ©reuses au stress rĂ©plicatif, caractĂ©risĂ©e par une catastrophe mitotique et la mort cellulaire par apoptose. Pour finir, nous avons montrĂ© que l’apoptose induite par le JMV5038 entrainait le relargage de signaux pouvant dĂ©clencher une rĂ©ponse immunitaire. Le JMV5038 serait donc un candidat original et pertinent pour dĂ©velopper une nouvelle famille d’agents Ă  utiliser, soit en association avec des chimiothĂ©rapies classiques induisant un stress rĂ©plicatif, soit en association avec des immunothĂ©rapies rĂ©centes, afin de stimuler et potentialiser leur activitĂ© thĂ©rapeutique anticancĂ©reuse.Melanoma is the deadliest form of skin cancer. This aggressiveness is due to a strong tendency to metastasize, resulting in a poor prognosis. Despite the introduction in 2011 of innovative therapeutic strategies (kinase inhibitors and immunotherapies), patients still face innate or acquired resistance and these new treatments offer only partial and temporary improvement. Due to an ever increasing global incidence, the development of new drugs and new therapeutic combinations acting against metastatic melanoma (MM) is a major public health challenge.JMV5038, a pyrido-imidazo [1,3] diazepinone produced by the team, had shown during a screening on the 60 cancer cell lines panel of the National Cancer Institute, a particularly interesting activity (GI50 of the order micromolar) on several lines. These results have been confirmed within our institute on several human malignant melanoma lines (MDA-MB-43, A375). The objective of this thesis was to clarify, by in vitro studies using as cell models 3 human lines of malignant melanoma (A375, MDA-MB-435, B16F10), the mechanism of action (MOA) of JMV5038. Our experimental strategy revolved around three objectives: (a) determining the intracellular localization of JMV5038, (b) developing tools to identify its pharmacological target(s) and (c) clarifying its molecular action mechanism. Raman imaging has proven to be the most suitable technique for determining the location/distribution of JMV5038, a small active molecule which is not intrinsically fluorescent. An accumulation of JMV5038 in the peri-membrane space of melanoma cells was thus demonstrated. From JMV5038, we developed pre-probes that will allow the identification of the pharmacological targets of JMV5038 in cellulo, by a chemical proteomic approach based on click-chemistry. This chemical development has also given us valuable information on the structure activity relationships (SAR) of diazepinones. Finally, functional studies have allowed us to make significant progress in the understanding of the MOA of JMV5038. Indeed, we have shown that the anti-tumor activity of JMV5038 is associated with an indirect and atypical inhibition of the Chk1 protein, involved in the DNA-damage responses pathway. This inhibition is due to an increase of the S280 phosphorylation of Chk1, leading to a modification of its location (cytoplasmic accumulation) and therefore potentially an inhibition of its activity. This defect in the ATR/Chk1 axis then leads to sensitization of cancer cells to replicative stress, characterized by a mitotic catastrophe and cell death by apoptosis. Finally, we have shown that apoptosis induced by JMV5038 leads to the release of signals that can trigger an immune response. JMV5038 would therefore be an original and relevant candidate to develop a new family of agents to be used, either in combination with conventional chemotherapies inducing replicative stress, or in association with recent immunotherapies, in order to stimulate and potentiate their anti-cancer therapeutic activity

    Les poly-tétraazamacrocycles (SynthÚse via un intermédiaire bis-aminal - Complexation d'ions de métaux de transition et de lanthanides)

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    La thÚse se divise en deux parties : La premiÚre est consacrée à la synthÚse de composés bis tétraazamacrocycliques, symétriques ou non, via des dérivés bis aminals du cyclam et du cyclen. La méthode est étendue aux tris macrocycles linéaires et cycliques. La deuxiÚme partie étudie les complexes des composés précédents avec les sels des métaux de transition : le cuivre (II) et le nickel (II). Ces complexes sont étudiés par voltammétrie cyclique et par RPE afin de mettre en évidence les éventuelles interactions entre les cations métalliques. Quelques bis-tétraazamacrocycles ont été modifiés par l'adjonction de bras acétate afin de complexer le gadolinium (III). Les composés ainsi obtenus présentent des performances supérieures à celles du DOTA Gd(III) comme agents de contraste en imagerie médicale par résonance magnétique.This work is divided into two parts : The first part is dedicated to synthesis of symmetrical or unsymmetrical bis tetraazamacrocyclic compounds, via bis aminal derivatives of cyclam and cyclen. This method is extended to linear and cyclic tris macrocyclic compounds. In the second part, we report the complexation of these poly tetraazamacrocycles with transition metal ions : Cu(II) and Ni(II). The complexes have been fully investigated by cyclic voltammetry and EPR to determine possible interactions between the metal centres. Carboxylic pendant arms have been grafted on some bis tetraazamacrocycles to coordinate Gd (III). Resulting complexes present better properties that DOTA Gd(III) as nuclear magnetic resonance imaging (MRI) contrast agents.BREST-BU Droit-Sciences-Sports (290192103) / SudocSudocFranceF
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