Recent advances in the management of gastrointestinal stromal tumors

This report focuses mainly on the major reduction of the risk of relapse of gastrointestinal stromal tumor (GIST) treated with imatinib, as identified in the American College of Surgeons Oncology Group (ACOSOG) Z9001 trial. It also focuses on the many unknowns associated with adjuvant imatinib therapy despite approvals by the US Food and Drug Administration and the European Medicines Agency, and on a new marker for the diagnosis of GIST

Structure et fonctionnement des communautés microbiennes dans la glace annuelle et pluriannuelle de la mer de Lincoln au printemps

RÉSUMÉ: La glace de mer est un écosystème unique au sein des régions polaires qui constitue un habitat pour une communauté de microorganismes diversifiée, active et spécialisée associée à la glace. La diminution de l'étendue et de l'épaisseur de glace de mer dans l'océan Arctique et le remplacement progressif de la glace pluriannuelle par la glace annuelle modifient l'habitat des communautés microbiennes présentes dans la glace de mer. Dans ce contexte de changement climatique et en raison de leur rôle central dans les cycles biogéochimiques des milieux marins, il est essentiel de caractériser la dynamique microbienne dans la glace de mer. Dans cette étude, nous évaluons la structure et le fonctionnement des communautés microbiennes dans la glace de mer annuelle et pluriannuelle de la mer de Lincoln en déterminant la répartition des bactéries et des virus ainsi que leur relation avec les facteurs biotiques et abiotiques. Nos résultats révèlent de forts gradients verticaux dans la répartition verticale des bactéries et des virus dans la glace de mer où les abondances sont plus élevées à la base de la glace. De plus, la répartition verticale des bactéries et des virus est similaire à celle des nutriments, du carbone organique dissous (COD) et de la chlorophylle a (chl a). Des relations significatives et positives entre l'abondance des bactéries et des virus et le phosphate, le COD, la chl a et le volume de saumure (un indice de la perméabilité de la glace) ont été mises en évidence pour la glace de mer annuelle et pluriannuelle en période printanière. Un modèle écologique basé sur l'analyse des coefficients de direction a révélé un réseau trophique microbien dans la glace de mer du Haut-Arctique canadien et un couplage étroit entre les bactéries et les algues via le COD et le phosphate. La même analyse souligne que les virus dans la glace de mer sont essentiellement bactériophages. Ce projet fournit de nouvelles connaissances sur la structure et le fonctionnement des microorganismes dans la glace annuelle et pluriannuelle de la mer de Lincoln, une région unique où la glace pluriannuelle devrait persister au cours des prochaines décennies. -- Mot(s) clé(s) en français : Glace de mer, bactéries, virus, répartition verticale, réseau microbien, mer de Lincoln, zone séculaire de glace, Haut-Arctique canadien. -- ABSTRACT: Sea ice is a unique ecosystem within the polar regions and constitutes a habitat for a diverse, active and specialized ice-associated community of microorganisms. The decline in sea ice extent and thickness in the Arctic Ocean and the gradual replacement of multiyear ice by first-year ice significantly alters the habitat of sea-ice microbial communities. In this context of climate change and due to their central role in biogeochemical cycles in marine systems, it is essential to characterize the dynamics of sea-ice microbes. In this study, we assess the structure and function of microbial communities in first-year and multiyear ice in the Lincoln Sea by determining the distribution of bacteria and viruses and their relationships with biotic and abiotic variables. Our results show strong vertical gradients in the distribution of bacteria and viruses in the ice, with higher bacterial and viral abundances at the bottom ice horizon. The vertical distribution of bacteria and viruses in the ice was closely related to that of nutrients, dissolved organic carbon (DOC) and chlorophyll a (chl a). Significant and positive relationships were found between bacterial and viral abundances and phosphate, DOC, chl a and brine volume (a proxy of sea ice permeability) in first-year and multiyear ice during spring. Ecological modelling through path analysis reveals an active microbial food web in the sea ice of the Canadian High Arctic and a tight coupling between bacteria and sea ice algae via DOC and phosphate. The same analysis highlights that viruses in sea ice are likely bacteriophages. This study provides new knowledge on the structure and functioning of microorganisms in first-year and multiyear ice in the Lincoln Sea, a unique region where multiyear ice is predicted to persist over the next decades. -- Mot(s) clé(s) en anglais : Sea ice, bacteria, viruses, vertical distribution, microbial food web, Lincoln Sea, Last Ice, Canadian High Arctic

Executive function and prefrontal cortex in rats

The term executive function describes a set of high-level abilities that influence more basic motor, sensory and mnemonic processes. These functions include working memory, behavioural flexibility, inhibitory control, attentional processes and decision making. A large number of evidence, from human studies, non-human primates, rats and mice studies, has demonstrated a role for the prefrontal cortex in these higher cognitive processes. The central aim of this thesis was to investigate two important aspects of the cognitive executive control: working memory and behavioural flexibility. The experiments described in the first two empirical chapters present the design of new operant paradigms to study these processes. Two further empirical chapters consider the neurobiological basis of behavioural flexibility, with a particular emphasize on the infralimbic (IL) and prelimbic (PL) regions of the rat medial prefrontal cortex (mPFC). Although, the IL and PL regions have generally been considered as a single functional unit, empirical findings presented in this thesis provide evidence suggesting that the IL and PL mPFC can be viewed as independent but interactive regions with complementary roles in the control of behaviour. That is, the PL brings simple cue-outcome associations and more complex behavioural patterns under the modulatory influence of contextual, or other task-relevant, information and in contrast, the IL exerts an inhibitory influence over the PL biasing the animal towards simple, prepotent, learned or innate behavioural patterns

Fusarium on french garlic, etiology and characterization of an emerging disease

Background: Yearly, France produces more than 20000 tons of garlic representing 3500 producersand 3000 ha. Since the mid-2000s and in spite of high demanding production specifications, aphytopathogenic fungus belonging to genus Fusarium, causes damage during storage leading to rootand bulb rots. The annual losses have a major impact on the viability of the French industry.Objectives: Two major objectives were to :• Elucidate the etiology of the disease on garlic• Develop a test to evaluate the aggressiveness of strainsMethods: Strains were isolated from the two major French production areas (South West and SouthEast) during the 2017 and 2018 production campaigns. Eleven garlic varieties on more than 90 plotswere used. All tested cloves were surface-sterilized with NaOCl and fungi were allowed to develop onPDA.To evaluate aggressiveness of each strain, twelve surface-sterilized cloves soaked in 1.0*106spores/mL were used. All cloves were placed separately at 23°C at saturated humidity for 18 days.Symptoms were noted with rating scale from 0 (absence of symptoms) to 5 (clove entirely brown).Every 2 days, Area Under the Disease Progress Curve was calculated for each clove.Results: In total, 1580 strains were successfully isolated, 262 identified (98% F. proliferatum and 2%F. oxysporum) and 48 tested for their aggressiveness. All varieties seemed to be infected equally,some plots more than the others. All tested strains shows aggressiveness on garlic, from 60 to 140%as compared to a reference strain

Executive function and prefrontal cortex in rats

The term executive function describes a set of high-level abilities that influence more basic motor, sensory and mnemonic processes. These functions include working memory, behavioural flexibility, inhibitory control, attentional processes and decision making. A large number of evidence, from human studies, non-human primates, rats and mice studies, has demonstrated a role for the prefrontal cortex in these higher cognitive processes. The central aim of this thesis was to investigate two important aspects of the cognitive executive control: working memory and behavioural flexibility. The experiments described in the first two empirical chapters present the design of new operant paradigms to study these processes. Two further empirical chapters consider the neurobiological basis of behavioural flexibility, with a particular emphasize on the infralimbic (IL) and prelimbic (PL) regions of the rat medial prefrontal cortex (mPFC). Although, the IL and PL regions have generally been considered as a single functional unit, empirical findings presented in this thesis provide evidence suggesting that the IL and PL mPFC can be viewed as independent but interactive regions with complementary roles in the control of behaviour. That is, the PL brings simple cue-outcome associations and more complex behavioural patterns under the modulatory influence of contextual, or other task-relevant, information and in contrast, the IL exerts an inhibitory influence over the PL biasing the animal towards simple, prepotent, learned or innate behavioural patterns.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Successive translocation into and out of the mitochondrial matrix

We investigated the import and sorting pathways of cytochrome b2 and cytochrome c1, which are functionally located in the intermembrane space of mitochondria. Both proteins are synthesized on cytoplasmic ribosomes as larger precursors and are processed in mitochondria in two steps upon import. The precursors are first translocated across both mitochondrial membranes via contact sites into the matrix. Processing by the matrix peptidase leads to intermediate-sized forms, which are subsequently redirected across the inner membrane. The second proteolytic processing occurs in the intermembrane space. We conclude that the hydrophobic stretches in the presequences of the intermediate-sized forms do not stop transfer across the inner membrane, but rather act as transport signals to direct export from the matrix into the intermembrane space

Lung metastasis 21 years after initial diagnosis of osteosarcoma: a case report

<p>Abstract</p> <p>Introduction</p> <p>To the best of our knowledge, this case report describes the longest disease-free interval between primary diagnosis and metastatic recurrence of an osteosarcoma.</p> <p>Case presentation</p> <p>A 35-year-old Caucasian American man presented with asymptomatic lung metastases 21 years after being diagnosed and treated for lower extremity osteosarcoma. He underwent curative lung resection, but 2 years thereafter developed metastatic disease in the scapula and tibia and, after resection and chemotherapy, is in remission 1 year later.</p> <p>Conclusion</p> <p>This case highlights the importance of long follow-up periods and continued surveillance of osteosarcoma patients after initial curative treatment.</p

Parallel declines in species and genetic diversity driven by anthropogenic disturbance: a multispecies approach in a French Atlantic dune system.

Numerous studies assess the correlation between genetic and species diversities, but the processes underlying the observed patterns have only received limited attention. For instance, varying levels of habitat disturbance across a region may locally reduce both diversities due to extinctions, and increased genetic drift during population bottlenecks and founder events. We investigated the regional distribution of genetic and species diversities of a coastal sand dune plant community along 240 kilometers of coastline with the aim to test for a correlation between the two diversity levels. We further quantify and tease apart the respective contributions of natural and anthropogenic disturbance factors to the observed patterns. We detected significant positive correlation between both variables. We further revealed a negative impact of urbanization: Sites with a high amount of recreational infrastructure within 10 km coastline had significantly lowered genetic and species diversities. On the other hand, a measure of natural habitat disturbance had no effect. This study shows that parallel variation of genetic and species diversities across a region can be traced back to human landscape alteration, provides arguments for a more resolute dune protection, and may help to design priority conservation areas