Metabolomics profiling of visceral adipose tissue: Results From MESA and the NEO study

Background Identifying associations between serum metabolites and visceral adipose tissue ( VAT ) could provide novel biomarkers of VAT and insights into the pathogenesis of obesity-related diseases. We aimed to discover and replicate metabolites reflecting pathways related to VAT . Methods and Results Associations between fasting serum metabolites and VAT area (by computed tomography or magnetic resonance imaging) were assessed with cross-sectional linear regression of individual-level data from participants in MESA (Multi-Ethnic Study of Atherosclerosis; discovery, N=1103) and the NEO (Netherlands Epidemiology of Obesity) study (replication, N=2537). Untargeted 1H nuclear magnetic resonance metabolomics profiling of serum was performed in MESA, and metabolites were replicated in the NEO study using targeted 1H nuclear magnetic resonance spectroscopy. A total of 30 590 metabolomic spectral variables were evaluated. After adjustment for age, sex, race/ethnicity, socioeconomic status, smoking, physical activity, glucose/lipid-lowering medication, and body mass index, 2104 variables representing 24 nonlipid and 49 lipid/lipoprotein subclass metabolites remained significantly associated with VAT ( P=4.88×10-20-1.16×10-3). These included conventional metabolites, amino acids, acetylglycoproteins, intermediates of glucose and hepatic metabolism, organic acids, and subclasses of apolipoproteins, cholesterol, phospholipids, and triglycerides. Metabolites mapped to 31 biochemical pathways, including amino acid substrate use/metabolism and glycolysis/gluconeogenesis. In the replication cohort, acetylglycoproteins, branched-chain amino acids, lactate, glutamine (inversely), and atherogenic lipids remained associated with VAT ( P=1.90×10-35-8.46×10-7), with most associations remaining after additional adjustment for surrogates of VAT (glucose level, waist circumference, and serum triglycerides), reflecting novel independent associations. Conclusions We identified and replicated a metabolite panel associated with VAT in 2 community-based cohorts. These findings persisted after adjustment for body mass index and appear to define a metabolic signature of visceral adiposity

A quantitative evaluation of the issue of drought definition: a source of disagreement in future drought assessments

Droughts are anticipated to intensify in many parts of the world due to climate change. However, the issue of drought definition, namely the diversity of drought indices, makes it difficult to compare drought assessments. This issue is widely known, but its relative importance has never been quantitatively evaluated in comparison to other sources of uncertainty. Here, encompassing three drought categories (meteorological, agricultural, and hydrological droughts) with four temporal scales of interest, we evaluated changes in the drought frequency using multi-model and multi-scenario simulations to identify areas where the definition issue could result in pronounced uncertainties and to what extent. We investigated the disagreement in the signs of changes between drought definitions and decomposed the variance into four main factors: drought definitions, greenhouse gas concentration scenarios, global climate models, and global water models, as well as their interactions. The results show that models were the primary sources of variance over 82% of the global land area. On the other hand, the drought definition was the dominant source of variance in the remaining 17%, especially in parts of northern high-latitudes. Our results highlight specific regions where differences in drought definitions result in a large spread among projections, including areas showing opposite signs of significant changes. At a global scale, 7% of the variance resulted independently from the definition issue, and that value increased to 44% when 1st and 2nd order interactions were considered. The quantitative results suggest that by clarifying hydrological processes or sectors of interest, one could avoid these uncertainties in drought assessments to obtain a clearer picture of future drought change

Pélothérapie et étude "in vitro" de l'absorption cutanée

Dans cette étude, nous proposons un modèle "in vitro" de mesure des échanges transcutanés adapté pour tester et comparer les produits ainsi que les conditions opératoires utilisés en station thermale. Il s'agit d'une cellule de diffusion (modèle de Franz) modifiée pour approcher au mieux la physiologie humaine. Nous considérons les échanges transcutanés du calcium et du salicylate de sodium à partir de différents péloides. Les échanges calciques se montrent favorisés par une eau fortement calcique et une température d'application élevée tandis qu'un passage salicylé optimal est défini pour une concentration de 10-1 M/l après dissolution dans l'eau thermale

Hydraulicité dans les piscines thermales. Influence du nombre et de la forme des buses d'arrivée d'eau sur la circulation de l'eau

En vue de maintenir une bonne qualité microbiologique de l'eau minérale de piscines thermales, une étude hydraulique a été menée sur un bassin pilote. Elle a comparé deux configurations différentes quant au nombre et à la forme des buses d'admission d'eau. L'hydraulique est inversée, l'ajout du traceur (rhodamine WT) est instantané, le circuit ouvert. Les résultats montrent que, pour ce bassin, une configuration comprenant 6 buses multidirectionnelles réduit les circuits préférentiels et limite la diffusion d'une pollution localisée en comparaison d'une configuration de 2 buses centrales