Modélisation des systèmes complexes par composition décomposition en sous ensembles (application à la biodisponibilité du phosphore provenant de phosphates naturels)

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

The use of diagnostic tools to manage the nitrogen fertilization of potato in Tunisia

The apply of high rates of nitrogen to fertilize potato constitutes an economic constraint for the tunisian farmer because of the elevated price of the nitrogenous manures. It constitutes also an environmental constraint because of leaching of nitrates which pollute the groundwater. In order to adjust the crop nitrogen supply to potato needs, an experiment was conducted in 2008 with the objectives of setting up a diagnostic tool (Nitrogen Nutrition Index, chlorophyll meter) to assess the nutrition status of potato and to help the farmer to a better fertilizer management.For a yield of 50t.ha-1, five urea treatments were applied: 0, 50, 150, 200 and 300 kg N.ha-1. Phosphoric acid and potassium sulphate were applied with 150 kg.ha-1 of P2O5 and 360 kg.ha-1 of K2O. The variety Spunta was planted in a clay loam soil and was drip irrigated.The relationships between shoot dry matter and total nitrogen concentration corresponding to the nitrogen treatments showed a deficient nitrogen status of plants and a difficulty to establish the critical dilution curve. The calibration of HNT was difficult due to the lowers correlations between HNT and NNI. The method of nitrogen balance and the calculation of the coefficient of nitrogen use showed a non availability of nitrogen to plants explained by elevated nitrogen losses by leaching or denitrification

Attenuation of Intestinal Inflammation in Interleukin-10-Deficient Mice Infected with Citrobacter rodentium

Interleukin-10 (IL-10) curtails immune responses to microbial infection and autoantigens and contributes to intestinal immune homeostasis, yet administration of IL-10 has not been effective at attenuating chronic intestinal inflammatory conditions, suggesting that its immune functions may be context dependent. To gain a broader understanding of the importance of IL-10 in controlling mucosal immune responses to infectious challenges, we employed the murine attaching and effacing pathogen Citrobacter rodentium, which colonizes primarily the surfaces of the cecum and colon and causes transient mucosal inflammation driven by Th17 and Th1 T helper cells. Infection induced macrophage and dendritic cell production of IL-10, which diminished antibacterial host defenses, because IL-10-deficient mice cleared infection faster than wild-type controls. In parallel, the mice had less acute infection-associated colitis and resolved it more rapidly than controls. Importantly, transient C. rodentium infection protected IL-10-deficient mice against the later development of spontaneous colitis that normally occurs with aging in these mice. Genome-wide expression studies revealed that IL-10 deficiency was associated with downregulation of proinflammatory pathways but increased expression of the anti-inflammatory cytokine IL-27 in response to infection. IL-27 was found to suppress in vitro Th17 and, to a lesser degree, Th1 differentiation independent of IL-10. Furthermore, neutralization of IL-27 resulted in more severe colitis in infected IL-10-deficient mice. Together, these findings indicate that IL-10 is dispensable for resolving C. rodentium-associated colitis and further suggest that IL-27 may be a critical factor for controlling intestinal inflammation and Th17 and Th1 development by IL-10-independent mechanisms

Pancreatic surgery outcomes: multicentre prospective snapshot study in 67 countries

Background: Pancreatic surgery remains associated with high morbidity rates. Although postoperative mortality appears to have improved with specialization, the outcomes reported in the literature reflect the activity of highly specialized centres. The aim of this study was to evaluate the outcomes following pancreatic surgery worldwide.Methods: This was an international, prospective, multicentre, cross-sectional snapshot study of consecutive patients undergoing pancreatic operations worldwide in a 3-month interval in 2021. The primary outcome was postoperative mortality within 90 days of surgery. Multivariable logistic regression was used to explore relationships with Human Development Index (HDI) and other parameters.Results: A total of 4223 patients from 67 countries were analysed. A complication of any severity was detected in 68.7 percent of patients (2901 of 4223). Major complication rates (Clavien-Dindo grade at least IIIa) were 24, 18, and 27 percent, and mortality rates were 10, 5, and 5 per cent in low-to-middle-, high-, and very high-HDI countries respectively. The 90-day postoperative mortality rate was 5.4 per cent (229 of 4223) overall, but was significantly higher in the low-to-middle-HDI group (adjusted OR 2.88, 95 per cent c.i. 1.80 to 4.48). The overall failure-to-rescue rate was 21 percent; however, it was 41 per cent in low-to-middle-compared with 19 per cent in very high-HDI countries.Conclusion: Excess mortality in low-to-middle-HDI countries could be attributable to failure to rescue of patients from severe complications. The authors call for a collaborative response from international and regional associations of pancreatic surgeons to address management related to death from postoperative complications to tackle the global disparities in the outcomes of pancreatic surgery (NCT04652271; ISRCTN95140761)