Rôle des protéines PII dans la régulation de l'activité et de l'état de modification de la nitrogénase chez Rhodobacter capsulatus

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Régulation du transport de glucose par le [bêta]-hydroxybutyrate dans le muscle cardiaque

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal

Insomnia and somnolence in idiopathic RBD : a prospective cohort study

Although some sleep disorders are markers of prodromal Parkinson’s disease and dementia with Lewy bodies, it is unclear whether insomnia and somnolence can predict disease. We assessed a large cohort of patients with idiopathic rapid eye movement sleep behavior disorder and age/sex matched controls, comparing the Epworth sleepiness scale, the Insomnia Severity Index, the Pittsburgh Sleep Quality Index, and polysomnographic variables. In those with repeated scales, we assessed change over time. Finally, we assessed whether sleep abnormalities predicted defined neurodegenerative disease. The 151 patients (age = 65.9, 75% male) completed sleep scales and were included. Epworth scores were similar between patients and controls (7.0+/−4.6 vs. 7.2 +/−4.7, p = 0.77), and did not progress with time (change = +0.46+/−2.1, p = 0.45). Epworth scores were similar between those who developed neurodegenerative disease and those remaining disease-free (6.7+/−4.4 vs. 7.1+/−4.7, p = 0.70). Pittsburgh Index scores were higher in patients than controls (7.2+/−3.8 vs. 4.9+/−3.4, p = 0.004), mainly driven by the sleep disturbance/medication components (reflecting rapid eye movement sleep behavior disorder symptoms/treatment). Baseline Pittsburgh scores did not predict conversion to neurodegeneration, although sleep duration increased over time in those converting to neurodegenerative disease (+0.88+/−1.32 h, p = 0.014). Insomnia index scores were higher in patients than controls (10.0+/−5.5 vs. 6.35+/−4.66, p < 0.001), but declined over time (−1.43+/−5.09, p = 0.029) particularly in those converting to neurodegenerative disease. Finally, on polysomnogram, those with increased tonic rapid eye movement had higher risk of developing defined neurodegenerative disease (HR = 1.88, p = 0.039). In summary, we found that somnolence and insomnia do not predict neurodegeneration in idiopathic rapid eye movement sleep behavior disorder. As neurodegeneration progresses through prodromal stages, patients may have increasing sleep drive and duration

Du réchauffement aux conséquences écologiques : s’adapter, migrer ou disparaître?

Le réchauffement climatique est un phénomène planétaire menant à des changements dans les conditions environnementales, tels que la température et la quantité de précipitations, posant un défi de taille pour les espèces sauvages. De nombreux scientifiques étudient les réponses biologiques des plantes et des animaux face à ces changements. Cet article est un aperçu des connaissances scientifiques sur les stratégies et réponses écologiques que les organismes vivants utilisent pour faire face, notamment, à l’augmentation des températures à l’échelle globale. Toutefois, pour certaines espèces, le réchauffement survient à une vitesse trop rapide, menant à leur disparition, et laissant parfois place à de nouvelles espèces

Changes in regional cerebral perfusion over time in idiopathic REM sleep behavior disorder

Background Idiopathic rapid eye movement sleep behavior disorder is associated with increased risk of neurodegeneration, but the temporal evolution of regional perfusion, a marker of cerebral activity, has not been characterized. The objective of the current study was to study longitudinal regional perfusion in patients with idiopathic rapid eye movement sleep behavior disorder. Methods Thirty‐seven patients and 23 controls underwent high‐resolution single‐photon emission computed tomography. After 17 months on average, scans were repeated for idiopathic rapid eye movement sleep behavior disorder patients. We compared regional cerebral blood flow between groups and over time. Results At baseline, patients showed lower relative regional perfusion in the anterior frontal and lateral parietotemporal cortex compared with controls. However, over time, patients showed an increase in relative regional perfusion in the anterior frontal, lateral parietal, and occipitotemporal cortex, reverting toward normal control levels. Conclusions Patients with idiopathic rapid eye movement sleep behavior disorder showed significant areas of relative regional hypoperfusion, which disappeared over time to finally return to average levels, suggesting possible developing compensation in areas affected by neurodegeneration

Choisir Paris : les grandes donations aux musées de la Ville de Paris

La Ville de Paris est l’un des premiers collectionneurs de France. Ses quatorze musées, réunis depuis 2013 au sein de l’établissement public Paris Musées, conservent une part importante de ce patrimoine. Nées de l’intérêt porté par la Ville à sa propre mémoire et à sa vie artistique, ces collections sont aussi le fruit du rapport passionné que de nombreux amateurs et collectionneurs ont entretenu avec la capitale, qu’ils ont choisie pour conserver leurs trésors patiemment assemblés. Ce « choix de Paris » répond à des motifs qui, pour divers qu’ils soient, font sens et écrivent une manière d’histoire de l’art. Hommage aux donateurs, le colloque dont sont issus ces actes s’est donné pour objectif de mieux faire connaître cette histoire, d’éclairer la genèse des collections des musées de la Ville de Paris et de témoigner de l’actualité de la recherche sur les grandes donations qui les ont enrichis. Ces essais témoignent aussi du souhait de Paris Musées de renforcer la recherche au sein de ses différentes activités

Risk and predictors of dementia and parkinsonism in idiopathic REM sleep behaviour disorder: a multicentre study

Idiopathic REM sleep behaviour disorder (iRBD) is a powerful early sign of Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. This provides an unprecedented opportunity to directly observe prodromal neurodegenerative states, and potentially intervene with neuroprotective therapy. For future neuroprotective trials, it is essential to accurately estimate phenoconversion rate and identify potential predictors of phenoconversion. This study assessed the neurodegenerative disease risk and predictors of neurodegeneration in a large multicentre cohort of iRBD. We combined prospective follow-up data from 24 centres of the International RBD Study Group. At baseline, patients with polysomnographically-confirmed iRBD without parkinsonism or dementia underwent sleep, motor, cognitive, autonomic and special sensory testing. Patients were then prospectively followed, during which risk of dementia and parkinsonsim were assessed. The risk of dementia and parkinsonism was estimated with Kaplan-Meier analysis. Predictors of phenoconversion were assessed with Cox proportional hazards analysis, adjusting for age, sex, and centre. Sample size estimates for disease-modifying trials were calculated using a time-to-event analysis. Overall, 1280 patients were recruited. The average age was 66.3 \ub1 8.4 and 82.5% were male. Average follow-up was 4.6 years (range = 1-19 years). The overall conversion rate from iRBD to an overt neurodegenerative syndrome was 6.3% per year, with 73.5% converting after 12-year follow-up. The rate of phenoconversion was significantly increased with abnormal quantitative motor testing [hazard ratio (HR) = 3.16], objective motor examination (HR = 3.03), olfactory deficit (HR = 2.62), mild cognitive impairment (HR = 1.91-2.37), erectile dysfunction (HR = 2.13), motor symptoms (HR = 2.11), an abnormal DAT scan (HR = 1.98), colour vision abnormalities (HR = 1.69), constipation (HR = 1.67), REM atonia loss (HR = 1.54), and age (HR = 1.54). There was no significant predictive value of sex, daytime somnolence, insomnia, restless legs syndrome, sleep apnoea, urinary dysfunction, orthostatic symptoms, depression, anxiety, or hyperechogenicity on substantia nigra ultrasound. Among predictive markers, only cognitive variables were different at baseline between those converting to primary dementia versus parkinsonism. Sample size estimates for definitive neuroprotective trials ranged from 142 to 366 patients per arm. This large multicentre study documents the high phenoconversion rate from iRBD to an overt neurodegenerative syndrome. Our findings provide estimates of the relative predictive value of prodromal markers, which can be used to stratify patients for neuroprotective trials

Conservation of Salmonella Infection Mechanisms in Plants and Animals

Salmonella virulence in animals depends on effectors injected by Type III Secretion Systems (T3SSs). In this report we demonstrate that Salmonella mutants that are unable to deliver effectors are also compromised in infection of Arabidopsis thaliana plants. Transcriptome analysis revealed that in contrast to wild type bacteria, T3SS mutants of Salmonella are compromised in suppressing highly conserved Arabidopsis genes that play a prominent role during Salmonella infection of animals. We also found that Salmonella originating from infected plants are equally virulent for human cells and mice. These results indicate a high degree of conservation in the defense and infection mechanism of animal and plant hosts during Salmonella infection