416 research outputs found

    Éditorial

    Get PDF
    Introduction L’adoption de la Convention Européenne du Paysages (CEP) en 2000 constitue un événement clef dans la prise en compte des paysages au niveau européen. À ce jour, trente‐huit pays ont ratifié la Convention adoptée sous l’égide du Conseil de l’Europe. En spécifiant que le paysage est une composante essentielle du cadre de vie des Européens, la convention s’inscrit avant toute chose dans une dimension territoriale. Par ailleurs, un fondement fort de la CEP réside dans la particularit..

    Structural and Functional Characterization of Sulfonium Carbon-Oxygen Hydrogen Bonding in the Deoxyamino Sugar Methyltransferase TyIM1

    Get PDF
    The N-methyltransferase TylM1 from Streptomyces fradiae catalyzes the final step in the biosynthesis of the deoxyamino sugar mycaminose, a substituent of the antibiotic tylosin. The high-resolution crystal structure of TylM1 bound to the methyl donor S-adenosylmethionine (AdoMet) illustrates a network of carbon-oxygen (CH•••O) hydrogen bonds between the substrate’s sulfonium cation and residues within the active site. These interactions include hydrogen bonds between the methyl and methylene groups of the AdoMet sulfonium cation and the hydroxyl groups of Tyr14 and Ser120 in the enzyme. To examine the functions of these interactions, we generated Tyr14 to phenylalanine (Y14F) and Ser120 to alanine (S120A)mutations to selectively ablate the CH•••O hydrogen bonding to AdoMet. The TylM1 S120A mutant exhibited a modest decrease in the catalytic efficiency relative to wild type (WT) enzyme, whereas the Y14F mutation resulted in an approximately 30-fold decrease in catalytic efficiency. In contrast, site-specific substitution of Tyr14 by the noncanonical amino acid p-aminophenylalanine partially restored activity comparable to the WT enzyme. Correlatively, quantum mechanical calculations of the activation barrier energies of WT TylM1 and the Tyr14 mutants suggest that substitutions which abrogate hydrogen bonding with the AdoMet methyl group impair methyl transfer. Together, these results offer insights into roles of CH•••O hydrogen bonding in modulating the catalytic efficiency of TylM1

    Practice Patterns and Preferences Among Hematopoietic Cell Transplantation Clinicians

    Get PDF
    Hematopoietic cell transplantation can cure many high-risk diseases but is associated with complexity, cost, and risk. Several areas in transplantation practice were identified in the 2014 Blood and Marrow Transplant Clinical Trials Network State of the Science Symposium (BMT CTN SOSS) as high priorities for further study. We developed a survey for hematopoietic cell transplantation clinicians to identify current practices in BMT CTN SOSS priority areas and to understand, more generally, the variation in approach to transplantation and estimation of transplantation benefit in current medical practice. Of 1439 transplantation clinicians surveyed, 305 responded (20% response rate). Clinicians were well represented by age, experience, geography, and size of practice. We found that several techniques identified in the BMT CTN SOSS, such as maintenance therapy for acute myeloid leukemia or myelodysplastic syndromes after allogeneic transplantation, were already being utilized in practice on and off study, with higher rates of use in higher-volume centers. There was significant variation among clinicians in use of transplantation technologies and approaches to common transplantation scenarios. Appraisals of risks and benefits of transplantation appeared to converge upon similar estimates despite the presentation of different hypothetical scenarios. These results suggest overall equipoise in several BMT CTN SOSS high-priority areas and support the need for better data to inform clinical practice

    Did giraffe cardiovascular evolution solve the problem of heart failure with preserved ejection fraction?

    Get PDF
    The evolved adaptations of other species can be a source of insight for novel biomedical innovation. Limitations of traditional animal models for the study of some pathologies are fueling efforts to find new approaches to biomedical investigation. One emerging approach recognizes the evolved adaptations in other species as possible solutions to human pathology. The giraffe heart, for example, appears resistant to pathology related to heart failure with preserved ejection fraction (HFpEF)-a leading form of hypertension-associated cardiovascular disease in humans. Here, we postulate that the physiological pressure-induced left ventricular thickening in giraffes does not result in the pathological cardiovascular changes observed in humans with hypertension. The mechanisms underlying this cardiovascular adaptation to high blood pressure in the giraffe may be a bioinspired roadmap for preventive and therapeutic strategies for human HFpEF

    Reading related white matter structures in adolescents are influenced more by dysregulation of emotion than behavior

    Get PDF
    Mood disorders and behavioral are broad psychiatric diagnostic categories that have different symptoms and neurobiological mechanisms, but share some neurocognitive similarities, one of which is an elevated risk for reading deficit. Our aim was to determine the influence of mood versus behavioral dysregulation on reading ability and neural correlates supporting these skills in youth, using diffusion tensor imaging in 11- to 17-year-old children and youths with mood disorders or behavioral disorders and age-matched healthy controls. The three groups differed only in phonological processing and passage comprehension. Youth with mood disorders scored higher on the phonological test but had lower comprehension scores than children with behavioral disorders and controls; control participants scored the highest. Correlations between fractional anisotropy and phonological processing in the left Arcuate Fasciculus showed a significant difference between groups and were strongest in behavioral disorders, intermediate in mood disorders, and lowest in controls. Correlations between these measures in the left Inferior Longitudinal Fasciculus were significantly greater than in controls for mood but not for behavioral disorders. Youth with mood disorders share a deficit in the executive-limbic pathway (Arcuate Fasciculus) with behavioral-disordered youth, suggesting reduced capacity for engaging frontal regions for phonological processing or passage comprehension tasks and increased reliance on the ventral tract (e.g., the Inferior Longitudinal Fasciculus). The low passage comprehension scores in mood disorder may result from engaging the left hemisphere. Neural pathways for reading differ mainly in executive-limbic circuitry. This new insight may aid clinicians in providing appropriate intervention for each disorder
    corecore