La réponse des tributaires du Saint-Laurent aux changements environnementaux : l'exemple du delta de la Yamachiche

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

A Comparative Study

Background: The Narcissism Inventory (NI) is a frequently used German inventory for measuring narcissism in clinical settings; an additional short version (NI-90) also exists. Psychometric properties of the NI-90 scales were examined in clinical and non-clinical adolescent samples. Methods: Two adolescent samples were assessed with the NI-90: a non-clinical sample (n = 439, mean age ± SD = 15.05 ± 1.77 years) and a clinical sample (n = 235, 18.26 ± 0.77 years). Confirmatory factor analysis and principle component analysis were used to scrutinize the structure of the scales. Multiple regression analysis was used to predict the scores on two scales (helpless self; negative body self). Results: This study revealed heterogeneity in the NI-90 scales, which in turn explains the wide range seen in Cronbach’s α (from 0.53 to 0.93). The postulated 4-factor structure could not be replicated in both samples. Multiple regression analysis revealed that personality disorder did not significantly predict negative body self or helpless self scores, whereas eating, mood, as well as somatoform and conversion disorders did. One NI-90 scale (greedy for praise and reassurance) showed sufficient psychometric quality for the measurement of narcissism in both samples. Conclusion: Based on the results, the authors recommend revising the NI-90. Items that may be useful for measuring aspects related to affective and body image complaints are presented. The greedy for praise and reassurance scale may be valuable for measuring features of ‘overt’ narcissism

Évolution récente du delta de la Yamachiche (Québec) : processus naturels et impacts anthropiques

Le lac Saint-Pierre, un élargissement du fleuve Saint-Laurent, pourrait connaître une baisse importante de niveau d’eau dans les cinquante prochaines années, conséquence du réchauffement climatique global. Sept rivières débouchent dans ce lac fluvial peu profond qui risquerait d’enregistrer une sédimentation importante. Nous avons étudié le delta de l’un de ces tributaires, la Yamachiche, pour évaluer les processus de sédimentation et les réponses de la rivière aux changements environnementaux passés. L’évolution du delta de la Yamachiche a été reconstituée par des photographies aériennes, des cartes anciennes, des analyses sédimentologiques et stratigraphiques de six coupes et de quatorze forages, et la datation par luminescence optique, 210Pb et 14C. Le delta est caractérisé par deux types de dépôts. La base est constituée de dépôts sableux de lit mineur du chenal, mis en place dans des conditions de sédimentation et d’érosion fréquentes. Ils sont surmontés par des dépôts limoneux de plaine d’inondation deltaïque, comprenant des lits sableux locaux. Ces dépôts présentent une variabilité latérale et longitudinale expliquée par les variations de niveau d’eau du lac et de la rivière à une échelle annuelle et décennale, par les migrations du chenal et par l’action érosive des vagues du lac Saint-Pierre. Le delta s’est formé depuis 150 ans, comme le montre la carte de 1859 où le delta n’était que très peu développé. La luminescence optique attribue des âges de 140 et de 280 ans aux dépôts sableux à la base. Les datations révèlent des taux d’accumulation verticale moyens compris entre 0,5 et 1,5 cm/an. Cette accumulation importante serait liée aux perturbations anthropiques affectant les sources sédimentaires du bassin versant depuis le début de la colonisation il y a 200 ans. L’âge récent du delta serait également expliqué par la stabilisation tardive du lac Saint-Pierre à son niveau actuel, qui est intervenue entre 1000 et 150 ans.Lake St. Pierre, being an enlargement of the St. Lawrence River, could experience a significant base level drop in the next fifty years as a consequence of global climate warming. Seven tributaries flow into this shallow lake, and base level changes could lead to increased sedimentation rates. We have studied the delta of the Yamachiche River, a tributary of Lake St. Pierre. The objective of the study is to document the active geomorphic processes and the response of the river to past environmental changes. We have reconstructed the evolution of the Yamachiche delta from aerial photos, historical maps, sedimentological and stratigraphic analysis of six sections and fourteen boreholes, and by sediment dating using optically stimulated luminescence, 210Pb and 14C. The subsurface deposits are divided into two facies : sandy low-water channel deposits at the base, and silty delta plain deposits at the top. Sedimentary sequences show changes along a longitudinal gradient driven by the level of the lake and the river dynamics on annual and decadal scales, and a high lateral variability driven by migration of the channel and by high-energy waves from Lake St. Pierre, which erode the downstream eastern part of the delta plain. Rapid progradation of the delta has occurred in the last 150 years, as demonstrated by the poor development of the delta on the 1859 map. Optically stimulated luminescence dating provides ages of 140 and 280 years at the base of the depositional sequence. These results are consistent with the chronological sequence deduced from the other dating methods. This framework gives mean accumulation rates between 0.5 and 1.5 cm/year. These high rates of sedimentation are likely linked to human activities in the watershed, which affected sedimentary sources since colonization of the St. Lawrence Lowlands 200 years ago. The young age of the delta could also be explained by the late stabilization of Lake St. Pierre at its present level, between 1000 and 150 years ago

Bifidobacterium mongoliense genome seems particularly adapted to milk oligosaccharide digestion leading to production of antivirulent metabolites

Background: Human milk oligosaccharides (HMO) could promote the growth of bifidobacteria, improving young children's health. In addition, fermentation of carbohydrates by bifidobacteria can result in the production of metabolites presenting an antivirulent activity against intestinal pathogens. Bovine milk oligosaccharides (BMO), structurally similar to HMO, are found at high concentration in cow whey. This is particularly observed for 3′-sialyllactose (3′SL). This study focused on enzymes and transport systems involved in HMO/BMO metabolism contained in B. crudilactis and B. mongoliense genomes, two species from bovine milk origin. The ability of B. mongoliense to grow in media supplemented with whey or 3′SL was assessed. Next, the effects of cell-free spent media (CFSM) were tested against the virulence expression of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium. Results: Due to the presence of genes encoding β-galactosidases, β-hexosaminidases, α-sialidases and α-fucosidases, B. mongoliense presents a genome more sophisticated and more adapted to the digestion of BMO/HMO than B. crudilactis (which contains only β-galactosidases). In addition, HMO/BMO digestion involves genes encoding oligosaccharide transport systems found in B. mongoliense but not in B. crudilactis. B. mongoliense seemed able to grow on media supplemented with whey or 3′SL as main source of carbon (8.3 ± 1.0 and 6.7 ± 0.3 log cfu/mL, respectively). CFSM obtained from whey resulted in a significant under-expression of ler, fliC, luxS, stx1 and qseA genes (- 2.2, - 5.3, - 2.4, - 2.5 and - 4.8, respectively; P < 0.05) of E. coli O157:H7. CFSM from 3′SL resulted in a significant up-regulation of luxS (2.0; P < 0.05) gene and a down-regulation of fliC (- 5.0; P < 0.05) gene. CFSM obtained from whey resulted in significant up-regulations of sopD and hil genes (2.9 and 3.5, respectively; P < 0.05) of S. Typhimurium, while CFSM obtained from 3′SL fermentation down-regulated hil and sopD genes (- 2.7 and - 4.2, respectively; P < 0.05). Conclusion: From enzymes and transporters highlighted in the genome of B. mongoliense and its potential ability to metabolise 3′SL and whey, B. mongoliense seems well able to digest HMO/BMO. The exact nature of the metabolites contained in CFSM has to be identified still. These results suggest that BMO associated with B. mongoliense could be an interesting synbiotic formulation to maintain or restore intestinal health of young children

A versatile and easy method to calibrate a two-compartment flow cell for differential electrochemical mass spectrometry measurements

Catalysis and Surface Chemistr

The Chemerin/ChemR23 System Does Not Affect the Pro-Inflammatory Response of Mouse and Human Macrophages Ex Vivo

Macrophages constitute a major component of innate immunity and play an essential role in defense mechanisms against external aggressions and in inflammatory responses. Chemerin, a chemoattractant protein, is generated in inflammatory conditions, and recruits cells expressing the G protein-coupled receptor ChemR23, including macrophages. Chemerin was initially expected to behave as a pro-inflammatory agent. However, recent data described more complex activities that are either pro- or anti-inflammatory, according to the disease model investigated. In the present study, peritoneal macrophages were generated from WT or ChemR23−/− mice, stimulated with lipopolyssaccharide in combination or not with IFN-γ and the production of pro- (TNF-α, IL-1β and IL-6) and anti-inflammatory (IL-10) cytokines was evaluated using qRT-PCR and ELISA. Human macrophages generated from peripheral blood monocytes were also tested in parallel. Peritoneal macrophages from WT mice, recruited by thioglycolate or polyacrylamide beads, functionally expressed ChemR23, as assessed by flow cytometry, binding and chemotaxis assays. However, chemerin had no effect on the strong upregulation of cytokine release by these cells upon stimulation by LPS or LPS/IFN-γ, whatever the concentration tested. Similar data were obtained with human macrophages. In conclusion, our results rule out the direct anti-inflammatory effect of chemerin on macrophages ex vivo, described previously in the literature, despite the expression of a functional ChemR23 receptor in these cells

CITED2 cooperates with ISL1 and promotes cardiac differentiation of mouse embryonic stem cells

The transcriptional regulator CITED2 is essential for heart development. Here, we investigated the role of CITED2 in the specification of cardiac cell fate from mouse embryonic stem cells (ESC). The overexpression of CITED2 in undifferentiated ESC was sufficient to promote cardiac cell emergence upon differentiation. Conversely, the depletion of Cited2 at the onset of differentiation resulted in a decline of ESC ability to generate cardiac cells. Moreover, loss of Cited2 expression impairs the expression of early mesoderm markers and cardiogenic transcription factors (Isl1, Gata4, Tbx5). The cardiogenic defects in Cited2-depleted cells were rescued by treatment with recombinant CITED2 protein. We showed that Cited2 expression is enriched in cardiac progenitors either derived from ESC or mouse embryonic hearts. Finally, we demonstrated that CITED2 and ISL1 proteins interact physically and cooperate to promote ESC differentiation toward cardiomyocytes. Collectively, our results show that Cited2 plays a pivotal role in cardiac commitment of ESC

Summary of 2020 ESC guidelines on non-STE ACS, adult congenital heart disease, sports cardiology and atrial fibrillation.

peer reviewedDuring the ESC congress in September 2020, the new ESC guidelines were presented and are available on the ESC website. The new guidelines describe management recommendations on following cardiovascular diseases: non-STE ACS, adult congenital heart disease, sports cardiology and atrial fibrillation. The present document gives a summary of these guidelines and highlights the most important recommendations and changes in the management of these diseases. It will help to increase awareness about the new guidelines and may stimulate to consult the full document for specific items. Ultimately, the authors hope that this document will enhance implementation of new ESC guidelines in daily clinical practice