Impact de l'abreuvement du bétail sur la qualité écologique des cours d'eau : étude de cas en Région wallonne de Belgique.

peer reviewe

Fetal lung volume: Estimation at MR imaging - Initial results

PURPOSE: To plot normal fetal lung volume (FLV) obtained with fast spin-echo magnetic resonance (MR) images against gestational age; to investigate the correlation between lung growth and fetal presentation, sex, and ultrasonographic (US) biometric measurements; and to investigate its potential application in fetuses with thoracoabdominal malformations. MATERIALS AND METHODS: In a prospective multicenter study, 336 fetuses suspected of having central nervous system disorders underwent fast spin-echo T2-weighted lung MR imaging. Data obtained at 21-38 weeks gestation in 215 fetuses without thoracoabdominal malformations and with normal US biometric findings were selected for an FLY normative curve. FLV measurements obtained at pathologic examination with an immersion method were compared with MR FLV measurements in 11 fetuses. MR FLV values in 16 fetuses with thoracoabdominal malformations were compared with the normative curve. RESULTS: Normal FLV increased with gestational age as a power curve; the spread of values increased with age. Interobserver correlation was excellent (R2 = 0.96). FLV measurements at MR imaging were 0.90 times those at pathologic examination. A constant ratio (0.78) between FLV on the left and right sides was observed. No significant difference in FLV was observed between fetal presentations. Normal FLV was observed in all fetuses with cystic adenomatoid malformations and in four of six with oligohydramnios. Lowest FLV values were observed in fetuses with diaphragmatic hernia. CONCLUSION: In fetuses with normal lungs, FLV distribution against gestational age is easily assessed in utero with fast spin-echo T2-weighted MR imaging. These preliminary findings illustrate the potential for comparing FLV measurements in fetuses at risk of lung hypoplasia with normative values.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Fetal lung volume: Estimation by MRI-Initial Results

info:eu-repo/semantics/publishe

Prenatal prognosis of congenital diaphragmatic hernia using magnetic resonance imaging measurement of fetal lung volume

Objectives: To investigate the correlation between fetal lung volume (FLV), measured with magnetic resonance imaging (MRI), and postnatal mortality in newborns with prenatally diagnosed isolated congenital diaphragmatic hernia (CDH). Methods: In a 4-year prospective multicenter study, 77 fetuses with isolated CDH diagnosed between 20 and 33 weeks' gestation underwent fast spin-echo T2-weighted lung MRI. These MRI-FLV measurements were compared with a previously published normative curve obtained in 215 fetuses without thoracoabdominal malformations and with normal ultrasound biometric findings. FLV measurements were correlated with postnatal survival. The mean gestational age at MRI was 31.3 weeks. Results: The measured/expected FLV ratio was significantly lower in the newborns with CDH who died compared with those who survived (23.6 ± 12.2 vs. 36.1 ± 13.0, P < 0.001). When the ratio was below 25%, there was a significant decrease in postnatal survival (19% vs. 40.3%, P = 0.008). Survival was significantly lower for neonates when one lung could not be seen by fetal MRI compared with those fetuses with two visible lungs on MRI (17.9% vs. 62.1%, P < 0.001). Conclusion: In isolated CDH, FLV measurement by MRI is a good predictor of postnatal mortality due to pulmonary hypoplasia. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.SCOPUS: ar.jFLWINinfo:eu-repo/semantics/publishe

Effect of mineralogical, geochemical and biological properties on soils reflectance to assess temporal and spatial dynamics of BSCs in Sahelian ecosystems

International audienceLand degradation and desertification are among the major environmental problems, resulting in reduced productivity and development of bare surfaces in arid and semi-arid areas of the world. One important factor that acts to increase soil stability and nutrient content, and thus to prevent water and wind erosion and enhance soil productivity of arid environment, is the presence of biological soil crusts (BSCs). They are the dominant ground cover and a key component of arid environments built up mainly by cyanobacteria. They enhance degraded soil quality by providing a stable and water-retaining substratum and increasing fertility by N and C fixations. The BioCrust project, funded by ANR (VMCS 2008), focuses on BSCs in the Sahelian zone of West Africa (Niger), a highly vulnerable zone facing soil degradation due to the harsh climatic conditions, with variable rainfall, and high anthropic pressure on land use. Unlike arid areas of developed countries (USA, Australia and Israel) or China where BSCs have been extensively studied, studies from Sahelian zone (Africa) are limited (neither the inventory of their different form nor the estimation of their spatial extension has been carried out). The form, structure and composition of BSCs vary depending on characteristics related to soils and biological composition. This study focuses on the soils characterisation using ground-based spectroradiometry. An extensive database was built included spectral measurements on BSCs, bare soils and vegetation that occur in the same area, visual criteria, in situ and laboratory measurements on the physical, chemical and biological characteristics of BSCs and their substratum. The work is carried out on geo-statistical processing of data acquired in sites along a north-south climatic gradient and three types of representative land uses. The investigated areas are highly vulnerable zone facing soil degradation due to the harsh climatic conditions, with variable rainfall, and high anthropic pressure on land use Soil surface disturbances due to the intensification of human activities. Spectral field and laboratory data were acquired in February 2009 with the FieldSpec Pro® The spectra of soils with respect to different parameters are studied in details and their separability from BSCs, vegetation and vegetation residue as well are be analysed. First, the effect of the mineralogy and the geochemical variables on the soil reflectance properties is studied and then the feasibility to resolve some of these effects with satellite imagery (e. g., ASTER) will be tested in order to define the potential capability for identifying the locations of sensitive areas affected by soil degradation and appearance of BSCs

Vulnérabilité des croûtes biologiques et dégradation des sols en zone sahélienne

National audienceLes Croûtes Biologiques de Surface (BSC), ou croûtes microbiotiques, résultent essentiellement de la colonisation de la surface du sol par des micro-organismes, en majorité des cyanobactéries. Ces croûtes représentent un état structural typique des sols nus dans les écosystèmes semi-arides, arides et désertiques. Les micro-organismes qui les composent ont la particularité de fixer l'azote et le carbone atmosphérique. Ils contribuent ainsi à l'amélioration de la qualité des sols dégradés, notamment via la formation de substrats stables vis-à-vis de l'érosion et l'apport de nutriments. Le développement et le fonctionnement de ces croûtes sont profondément affectés par les changements climatiques et les modalités d'usage des sols. Le projet BIOCRUST a pour objet l'étude des croûtes microbiotiques en zone sahélienne (Fig.1). Les sites d'études choisis permettront l'étude de la dynamique spatio-temporelle des BSC dans des contextes climatiques contrastés et sous la pression anthropique des pratiques pastorales et culturales locales

[Systematic review: value of perioperative chemotherapy in the management of resectable rectal adenocarcinoma (brief report)]

International audienceAt the request of the National Thesaurus of Gastrointestinal Cancer (TNCD), the SOR program undertaken by the French federation of cancer centers and now led by the French National Cancer Institute, completed a systematic review to evaluate the value of perioperative chemotherapy in the management of resectable rectal adenocarcinoma in collaboration with clinician experts. METHODS: Results of a systematic literature search using Medline and Embase (from January 1996 to October 2007) were completed by a survey of Evidence- Based Medicine websites. All phase III randomized trials and systematic reviews comparing surgery (alone or associated with adjuvant therapy) to the same treatment plus chemotherapy, or comparing different perioperative chemotherapy modalities in patients with resectable rectal adenocarcinoma, were included in the study. The quality and clinical relevance of the trials were evaluated using validated checklists, allowing to associate each result with its level of evidence. Data synthesis was performed taking into account both efficacy and toxicity outcomes for each intervention. Finally, research recommendations were formulated. RESULTS: Of 29 studies meeting the selection criteria, 19 were included after critical methodological and clinical appraisal. As compared with preoperative radiotherapy, preoperative chemoradiotherapy with 5-fluorouracil and folinic acid does not improve overall or relapse-free survivals but decreases local recurrence rates. Postoperative chemotherapy with 5-fluorouracil and folinic acid does not improve overall or relapse-free survivals, whether the patients received preoperative radiotherapy or preoperative chemoradiotherapy, whereas it seems to decrease local recurrence rates after preoperative radiotherapy but not after preoperative chemoradiotherapy. As compared with postoperative chemoradiotherapy, preoperative chemoradiotherapy with continuous infusion of 5-fluorouracil does not improve overall or relapse-free survivals, but decreases local recurrence rates as well as acute and long-term toxicities. In the absence of preoperative radiotherapy, fluoropyrimidine-based postoperative chemotherapy improves both overall and relapse-free survivals and decreases local recurrence rates. CONCLUSIONS: Preoperative chemoradiotherapy reduces the risk of local recurrence as compared with preoperative radiotherapy or postoperative chemoradiotherapy