Comparing chemical environmental scores using USEtox<Superscript>™</Superscript> and CDV from the European Ecolabel

Purpose

USEtox^? (Rosenbaum et al. 2008) is a new model which can be used to calculate characterization factors for human and ecotoxicity impact categories used in life cycle assessment. The French ADEME-AFNOR (http://affichage-environnemental.afnor.org/) is currently considering this model to develop a new environmental labelling standard for consumer goods. The objective of this short study is to compare USEtox^? impact scores with critical dilution volume (CDV) scores from the European Ecolabel (http://ec.europa.eu/environment/ecolabel), a well-established tool widely used in Europe aiming at discriminating environmental friendly products.

Material and methods

The same range of chemicals (high scores to low scores) listed in both the USEtox^? database and the EU Ecolabel detergent ingredient database (DID-list) were used for the comparison. The DID-list is a reference list, which contains agreed and verified fate and ecotoxicity data. The ranking was made based on two different ranking parameters, one from each model: the environmental impact score from USEtox^? and the CDV from the EU Ecolabel. Additionally, a Spearman’s rank correlation (ρ) coefficient was calculated.

Results and discussion

Sixty-nine chemicals common in personal care and cleaning products were selected for the comparison between USEtox^? and EU Ecolabel methods. A “fair” agreement was found between the two models with a Spearman correlation coefficient ρ of 0.74, but a significant number of chemicals was ranked rather differently. The presence of outliers (i.e., different ranking) may be explained by several factors, which include the use of discrete versus continuous values to estimate the substance’s degradation constant. Another factor could be that the substances are grouped under classes in the DID-list, thus having average parameter values. The main factor though probably lays in the different sources of the physico-chemical, fate and ecotoxicity data within the two model databases and the different way they are used for the ranking parameter calculation.

Conclusions

Provided there is scientific consensus (and full transparency) on the raw data, both USEtox^? and EU Ecolabel methods are relevant for ranking chemicals based on their physico-chemical and toxicological properties, and therefore for calculating product environmental impact scores related to their hazard. However, the presence of a number of chemicals with different ranking scores creates the risk of inconsistent consumer product information when either the CDV (EU ecolabel) or USEtox^? (French “Affichage Environnemental”) is used for environmental labelling. To date, and for sake of consistency with an existing and used labelling scheme, the CDV appears much easier to implement with less uncertainty to calculate ecotoxicity impact score of products.

     

Common ground: small RNA programming and chromatin modifications

Epigenetic mechanisms regulate genome structure and expression profiles in eukaryotes. RNA interference (RNAi) and other small RNA-based chromatin-modifying activities can act to reset the epigenetic landscape at defined chromatin domains. Centromeric heterochromatin assembly is a RNAi-dependent process in the fission yeast Schizosaccharomyces pombe, and provides a paradigm for detailed examination of such epigenetic processes. Here we review recent progress in understanding the mechanisms that underpin RNAi-mediated heterochromatin formation in S. pombe. We discuss recent analyses of the events that trigger RNAi and manipulations which uncouple RNAi and chromatin modification. Finally we provide an overview of similar molecular machineries across species where related small RNA pathways appear to drive the epigenetic reprogramming in germ cells and/or during early development in metazoans.     

Reproducibility in Echocardiographic Assessment of Diastolic Function in a Population Based Study (The STANISLAS Cohort Study)

Introduction

There is limited evidence regarding intra-observer and inter-observer variations in echocardiographic measurements of diastolic function. This study aimed to assess this reproducibly within a population-based cohort study.

Methods

Sixty subjects in sinus rhythm were randomly selected among 4^th visit participants of the STANISLAS Cohort (Lorraine region, France). This 4^th examination systematically included M-mode, 2-dimensional, DTI and pulsed-wave Doppler echocardiograms. Reproducibility of variables was studied by intra-class correlation coefficients (ICC) and Bland Altman plots.

Results

Our population was on average middle-aged (50 ± 14y), overweight (BMI = 26 ± 6kg/m²) and non-smoking (87%) with a quarter of the participants having self-declared hypertension or treated with anti-hypertensive medication(s). Intra-observer ICC were > 0.90 for all analyzed parameters except for left ventricular ejection fraction (LVEF) which was 0.89 (0.81–0.93). The mean relative intra-observer differences were small and limits of agreement of relative differences were narrow for all considered parameters (<5% and <15% respectively). Inter-observer ICC were > 0.90 for all analyzed parameters except for LVEF (ICC = 0.87) and both mitral and pulmonary A wave duration (0.83 and 0.73 respectively). The mean relative inter-observer differences were <5% for all parameters except for pulmonary A wave duration (mean difference = 6.5%). Limits of agreement of relative differences were narrow (<15%), except for mitral A wave duration and velocity (both <20%) as well as left ventricular mass and pulmonary A wave duration (both <30%). Intra-observer agreements with regard to the presence and severity of diastolic dysfunction were excellent (Kappa = 0.93 (0.83–1.00) and 0.88 (0.75–0.99), respectively).

Conclusion

In this validation study within the STANISLAS cohort, diastolic function echocardiographic parameters were found to be highly reproducible. Diastolic dysfunction consequently appears as a highly effective clinical and research tool.     

Time to exhaustion and time spent at a high percentage of VO2max in severe intensity domain in children and adults

The aim of the study was to compare time spent at a high percentage of VO2max (>90% of VO2max) (ts90%), time to achieve 90% of VO2max (ta90%), and time to exhaustion (TTE) for exercise in the severe intensity domain in children and adults. Fifteen prepubertal boys (10.3 ± 0.9 years) and 15 men (23.5 ± 3.6 years) performed a maximal graded exercise to determine VO2max, maximal aerobic power (MAP) and power at ventilatory threshold (PVTh). Then, they performed 4 constant load exercises in a random order at PVTh plus 50 and 75% of the difference between MAP and PVTh (PΔ50 and PΔ75) and 100 and 110% of MAP (P100 and P110). VO2max was continuously monitored. The P110 test was used to determine maximal accumulated oxygen deficit (MAOD). No significant difference was found in ta90% between children and adults. ts90% and TTE were not significantly different between children and adults for the exercises at PΔ50 and PΔ75. However, ts90% and TTE during P100 (p < 0.05 and p < 0.01, respectively) and P110 (p < 0.001) exercises were significantly shorter in children. Children had a significantly lower MAOD than adults (34.3 ± 9.4 ml · kg vs. 53.6 ± 11.1 ml · kg). A positive relationship (p < 0.05) was obtained between MAOD and TTE values during the P100 test in children. This study showed that only for intensities at, or higher than MAP, lower ts90% in children was linked to a reduced TTE, compared to adults. Shorter TTE in children can partly be explained by a lower anaerobic capacity (MAOD). These results give precious information about exercise intensity ranges that could be used in children's training sessions. Moreover, they highlight the implication of both aerobic and anaerobic processes in endurance performances in both populations.     

Aerial and underwater carbon metabolism of a Zostera noltii seagrass bed in the Banc d’Arguin, Mauritania

Community respiration and primary production were measured in a dense intertidal Zostera noltii bed on the Banc d’Arguin, Mauritania (West Africa) under aerial and submerged conditions. Metabolism was studied in situ in dark and transparent benthic chambers. CO₂ fluxes in the air were measured over a series of short-term incubations (3 min) using an infrared gas analyzer. Dissolved inorganic carbon fluxes were calculated from concentration changes during one-hour underwater incubations. Air and underwater irradiance levels were measured every minute throughout the experiments. Carbon respiration was lower in the air (2.2 mmol m⁻² h⁻¹) than underwater (5.0 mmol m⁻² h⁻¹); similarly, a production-irradiance model fitted to the data indicated that gross maximal photosynthetic rate was markedly lower during emergence (6.0 mmol C m⁻² h⁻¹) than under water (42.7 mmol C m⁻² h⁻¹). The δ¹³C values observed in shoots indicated a decrease in atmospheric CO₂ contribution, compared to dissolved inorganic carbon, in Z. noltii metabolism along a depth gradient within a single location. As the seagrass bed remains under a thin layer of water at low tide at the studied site, the large difference in primary production can be mainly attributed to photosynthesis inhibition by high pH and oxygen concentration, as well as to the negative feedback of self-shading by seagrass leaves during emersion. The observed differences in respiration can be explained by the oxygen deficit at night during low tide near the sediment surface, a deficit that is consistent with the abundance of anoxia-tolerant species.     

Toxoplasma polymorphic effectors determine macrophage polarization and intestinal inflammation

European and North American strains of the parasite Toxoplasma gondii belong to three distinct clonal lineages, type I, type II, and type III, which differ in virulence. Understanding the basis of Toxoplasma strain differences and how secreted effectors work to achieve chronic infection is a major goal of current research. Here we show that type I and III infected macrophages, a cell type required for host immunity to Toxoplasma, are alternatively activated, while type II infected macrophages are classically activated. The Toxoplasma rhoptry kinase ROP16, which activates STAT6, is responsible for alternative activation. The Toxoplasma dense granule protein GRA15, which activates NF-κB, promotes classical activation by type II parasites. These effectors antagonistically regulate many of the same genes, and mice infected with type II parasites expressing type I ROP16 are?protected against Toxoplasma-induced ileitis. Thus, polymorphisms in determinants that modulate?macrophage activation influence the ability of Toxoplasma to establish a chronic infection.