Cultures maraîchères après destruction de prairies permanentes: risques environnementaux et intérêts agronomiques

La dernière version du Programme de Gestion Durable de l'Azote (PGDA III) entré en application en Juin 2014, interdit de cultiver des légumes pendant une période de deux ans, après destruction de prairie permanente. Cette interdiction est considérée comme un frein au développement du maraîchage biologique. Est-elle totalement justifiée? Une situation bien gérée peut-elle permettre de limiter les risques de lixivation de nitrate

Cultures maraîchères après destruction de prairie permanente: risques environnementaux et intérêts agronomiques

La dernière version du Programme de Gestion durable de l'Azote (PGDA III), entré en application en juin 2014, interdit de cultiver des légumes pendant une durée de deux ans après destruction de prairie permanente. Cette interdiction est considéré comme un frein au développement du maraîchage biologique. Est-ce totalement justifié? Une situation bien gérée peut-elle permettre de limiter les risques de lixiviation de nitrate

Glomerular filtration rate: assessment with dynamic contrast-enhanced MRI and a cortical-compartment model in the rabbit kidney.

PURPOSE: To describe the use of MRI and a cortical-compartment model to measure the glomerular filtration rate (GFR), and compare the results with those obtained with the Patlak-Rutland model. MATERIALS AND METHODS: Dynamic MRI of rabbit kidneys was performed during and after injection of gadoterate dimeglumine. The enhancement curves in the aorta and the kidney were analyzed with the cortical-compartment and Patlak-Rutland models to assess the GFR. RESULTS: A substantial correlation was observed between the GFR measured with MRI using the cortical-compartment model and the plasma clearance of 51Cr-EDTA (r=0.821, P=0.004). No significant correlation was observed between the 51Cr-EDTA clearance (r=0.628, P=0.052) and the GFR obtained with the Patlak-Rutland model in regions of interest (ROIs) encompassing the renal cortex and medulla. A Bland and Altman analysis showed that GFR(cortical) (compartment) agreed better with the 51Cr-EDTA clearance compared to GFR(Patlak) when ROIs were limited to the cortex. However, the GFR values obtained by MRI were lower than the plasma clearance of 51Cr-EDTA. CONCLUSION: MRI with a cortical-compartment model provides more accurate assessments of glomerular filtration than the Patlak-Rutland model