Modélisation déterministe de la crue extrême d'un bassin versant de montagne avec application de la description géomorphologique du réseau hydrographique

Les méthodes de calcul des crues de projet pour des grands barrages sont de type statistique ou de type déterministe (PMP/PMF). Ce dernier type de méthodes est principalement utilisé dans le monde anglo-saxon (États-Unis, Australie), mais peut offrir une alternative intéressante aux méthodes statistiques, qui présentent des lacunes pouvant être importantes.Une application des méthodes PMP/PMF sur des bassins suisses a mis en évidence l'intérêt de ces méthodes, mais aussi leurs faiblesses. Une adaptation des outils déterministes est nécessaire pour prendre en compte les particularités des bassins de montagne. Il s'agit principalement de mieux tenir compte des propriétés physiques des bassins versants et des phénomènes de non linéarité. Dans ce but, un concept de modélisation utilisant la description géomorphologique du bassin versant a été utilisé et amélioré. Le premier modèle utilisé est l'hydrogramme unitaire géomorphologique, qui existe depuis 1979. Le deuxième modèle utilise le concept de cascade de réservoirs hydrologiques à vidange non linéaire, dont les éléments sont issus de la description géomorphologique du bassin. C'est là une modélisation nouvelle qui est particulièrement adaptée au contexte des crues extrêmes dans les Alpes. Un travail de calibration et validation du modèle a montré que ce modèle a un bon potentiel d'utilisation. La principale difficulté revient à identifier la signification physique des paramètres du modèle, qui pourrait s'appuyer sur les résultats d'un autre type de modélisation couplant la géomorphologie du bassin aux equations de l'onde cinématique. Ce modèle est en cours de test à l'IATE.Design floods for large dams are computed either with statistical or deterministic methods (Probable maximum precipitation, PMP/probable maximum flood, PMF). The latter presents an interesting alternative to statistical rnethods, whose drawbacks may be significant, especially when hydrometeorological data are deficient.PMP/PMF methods are based on assumption of the existence of an upper limit of the hydrometeorological processes. The prevalent method for PMP estimation is the maximization - transposition technique. Simpler methods, such as the statististically based technique, also exist. However, the most accurate method may well be the use of a meteorological model, but this aspect is still in the research domain.PMF is derived from a PMP using a simplified loss function and a transfer function for which parameters are maximized. The prevalent transfer function is the unit hydrograph model.Application of traditional PMP/PMF method on alpine catchments showed important weaknesses due to the transfer function. Alpine catchments are characterized by steep slopes, thin soil cover, poor vegetation, and large floods are due to heavy, short thunderstorms. Consequently, hydrological response is very sensitive to the topography of the catchment. Nonlinearity must be taken into account in many cases. However, experience showed that a model cannot take into account a detailed description of the catchment.In order to take into account the characteristcs of alpine catchments while staying as simple as possible, we have used the geomorphologic description of the catchment as a modeling basis. This representation is based on the Strahler ordering scheme, and defines all possible path types that a surface runoff dropret may follow to reach the outlet. This description has been used since 1979 in the geomorphologic unit hydrograph (GUH) formulation.We developed a geomorphorogic nonlinear cascade (GNC) in order to take into account nonlinear processes. The GNC model uses the geomorphologic description of the catchment to define the reservoirs of hydrological cascades. A cascade represents a path type; the first reservoir ofa cascade is an overland element and subsequent reservoirs are channels with increasing Strahler's order. Outflow from a reservoir is the inflow of the downstream reservoir. Outflows from all cascades are combined to produce the global catchment response. The two equations used in the GNC model are a global continuity equation: I - O = dV/dt, and a nonlinear outflow equation: O = k Vx, where I is an input term, that is precipitation for the first reservoir, and outflow from the upstream element for channel reservoirs, V is the volume of water stored in a reservoir at time t, k is a consfant, and x an exponent. The parameter k varies with each reservoir as a function of surface area (for overland erements) or rength (for channel elements). The exponent x should be between 1 and 2.The two models, GUH and GNC, have been calibrated with an automatic optimization procedure, and tested on the Vogelbach catchment. This catchment is located in the swiss alps (Arptar, canton of schwytz); it is a third order catchment, and its area is 1,55 km2. Both models gave good results, although the GUH model had a tendency to smooth the dischage.Inorder to improve the physical meaning of the moder parameters, we are testing a third model linking the geomorphologic description with the kinematic wave equations. Results are promising, but are not shorm in this paper.The hydrologic modeling based on the geomorphologic description of the catchment seems to be a good compromise between lumped modeb and detailed distributed models, which are difficult to apply

Sialic acid-modified antigens impose tolerance via inhibition of T-cell proliferation and de novo induction of regulatory T cells

Sialic acids are negatively charged nine-carbon carboxylated monosaccharides that often cap glycans on glycosylated proteins and lipids. Because of their strategic location at the cell surface, sialic acids contribute to interactions that are critical for immune homeostasis via interactions with sialic acid-binding Ig-type lectins (siglecs). In particular, these interactions may be of importance in cases where sialic acids may be overexpressed, such as on certain pathogens and tumors. We now demonstrate that modification of antigens with sialic acids (Sia-antigens) regulates the generation of antigen-specific regulatory T (Treg) cells via dendritic cells (DCs). Additionally, DCs that take up Sia-antigen prevent formation of effector CD4+ and CD8+ T cells. Importantly, the regulatory properties endowed on DCs upon Sia-antigen uptake are antigen-specific: only T cells responsive to the sialylated antigen become tolerized. In vivo, injection of Sia-antigen–loaded DCs increased de novo Treg-cell numbers and dampened effector T-cell expansion and IFN-γ production. The dual tolerogenic features that Sia-antigen imposed on DCs are Siglec-E–mediated and maintained under inflammatory conditions. Moreover, loading DCs with Sia-antigens not only inhibited the function of in vitro–established Th1 and Th17 effector T cells but also significantly dampened ex vivo myelin-reactive T cells, present in the circulation of mice with experimental autoimmune encephalomyelitis. These data indicate that sialic acid-modified antigens instruct DCs in an antigen-specific tolerogenic programming, enhancing Treg cells and reducing the generation and propagation of inflammatory T cells. Our data suggest that sialylation of antigens provides an attractive way to induce antigen-specific immune tolerance

A solitary bronchial papilloma with unusual endoscopic presentation: case study and literature review

<p>Abstract</p> <p>Background</p> <p>Solitary endobronchial papillomas (SEP) are rare tumors and most of them are described by case report. A misdiagnosis is common with viral related papillomas. A histopathological classification has recently permitted a major advancement in the understanding of the disease.</p> <p>Case Presentation</p> <p>We report a case of a mixed bronchial papilloma with an unusual endoscopic presentation. The literature was extensively reviewed to ascertain the unusual characteristics of the current case. A 39-year of age male was referred to our institution for the investigation of a slight hemoptysis. Routine examination was normal. A fibroscopy revealed an unusual feature of the right main bronchus. The lesion was a plane, non-bleeding, non-glistering sub-mucosal proliferation. No enhanced coloration was noticed. Biopsies revealed a mixed solitary bronchial papilloma. In situ HPV hybridization was negative. Endoscopic treatment (electrocautery) was effective with no relapse.</p> <p>Conclusion</p> <p>This lesion contrasts with the data of the literature where papilloma were described as wart-like lesions or cauliflower tumors, with symptoms generally related to bronchial obstruction. We advise chest physicians to be cautious with unusually small swollen lesions of the bronchi that may reveal a solitary bronchial papilloma. Endoscopic imaging can significantly contribute to the difficult diagnosis of SEP by pulmonary physicians and endoscopists.</p

Metabolic and Innate Immune Cues Merge into a Specific Inflammatory Response via the UPR

Erratum in : Metabolic and Innate Immune Cues Merge into a Specific Inflammatory Response via the UPR. [Cell. 2019]International audienceInnate immune responses are intricately linked with intracellular metabolism of myeloid cells. Toll-likereceptor (TLR) stimulation shifts intracellular metabolism toward glycolysis, while anti-inflammatorysignals depend on enhanced mitochondrial respiration. How exogenous metabolic signals affect theimmune response is unknown. We demonstrate that TLR-dependent responses of dendritic cells (DC)are exacerbated by a high fatty acid (FA) metabolic environment. FA suppress the TLR-inducedhexokinase activity and perturb tricarboxylic acid cycle metabolism. These metabolic changesenhance mitochondrial reactive oxygen species (mtROS) production and, in turn, the unfolded proteinresponse (UPR) leading to a distinct transcriptomic signature, with IL-23 as hallmark. Interestingly,chemical or genetic suppression of glycolysis was sufficient to induce this specific immune response.Conversely, reducing mtROS production or DC-specific deficiency in XBP1 attenuated IL-23expression and skin inflammation in an IL-23-dependent model of psoriasis. Thus, fine-tuning of innateimmunity depends on optimization of metabolic demands and minimization of mtROS-induced UPR

Airway and Esophageal Stenting in Patients with Advanced Esophageal Cancer and Pulmonary Involvement

BACKGROUND: Most inoperable patients with esophageal-advanced cancer (EGC) have a poor prognosis. Esophageal stenting, as part of a palliative therapy management has dramatically improved the quality of live of EGC patients. Airway stenting is generally proposed in case of esophageal stent complication, with a high failure rate. The study was conducted to assess the efficacy and safety of scheduled and non-scheduled airway stenting in case of indicated esophageal stenting for EGC. METHODS AND FINDINGS: The study is an observational study conducted in pulmonary and gastroenterology endoscopy units. Consecutive patients with EGC were referred to endoscopy units. We analyzed the outcome of airway stenting in patients with esophageal stent indication admitted in emergency or with a scheduled intervention. Forty-four patients (58+/-\-8 years of age) with esophageal stenting indication were investigated. Seven patients (group 1) were admitted in emergency due to esophageal stent complication in the airway (4 fistulas, 3 cases with malignant infiltration and compression). Airway stenting failed for 5 patients. Thirty-seven remaining patients had a scheduled stenting procedure (group 2): stent was inserted for 13 patients with tracheal or bronchial malignant infiltration, 12 patients with fistulas, and 12 patients with airway extrinsic compression (preventive indication). Stenting the airway was well tolerated. Life-threatening complications were related to group 1. Overall mean survival was 26+/-10 weeks and was significantly shorter in group 1 (6+/-7.6 weeks) than in group 2 (28+/-11 weeks), p<0.001). Scheduled double stenting significantly improved symptoms (95% at day 7) with a low complication rate (13%), and achieved a specific cancer treatment (84%) in most cases. CONCLUSION: Stenting the airway should always be considered in case of esophageal stent indication. A multidisciplinary approach with initial airway evaluation improved prognosis and decreased airways complications related to esophageal stent. Emergency procedures were rarely efficient in our experience

Axonal inclusions in spinocerebellar ataxia type 3

Protein aggregation is a major pathological hallmark of many neurodegenerative disorders including polyglutamine diseases. Aggregation of the mutated form of the disease protein ataxin-3 into neuronal nuclear inclusions is well described in the polyglutamine disorder spinocerebellar ataxia type 3 (SCA3 or Machado–Joseph disease), although these inclusions are not thought to be directly pathogenic. Neuropil aggregates have not yet been described in SCA3. We performed a systematic immunohistochemical study of serial thick sections through brains of seven clinically diagnosed and genetically confirmed SCA3 patients. Using antibodies against ataxin-3, p62, ubiquitin, the polyglutamine marker 1C2 as well as TDP-43, we analyzed neuronal localization, composition and distribution of aggregates within SCA3 brains. The analysis revealed widespread axonal aggregates in fiber tracts known to undergo neurodegeneration in SCA3. Similar to neuronal nuclear inclusions, the axonal aggregates were ubiquitinated and immunopositive for the proteasome and autophagy associated shuttle protein p62, indicating involvement of neuronal protein quality control mechanisms. Rare TDP-43 positive axonal inclusions were also observed. Based on the correlation between affected fiber tracts and degenerating neuronal nuclei, we hypothesize that these novel axonal inclusions may be detrimental to axonal transport mechanisms and thereby contribute to degeneration of nerve cells in SCA3

Malonylation of GAPDH is an inflammatory signal in macrophages.

Macrophages undergo metabolic changes during activation that are coupled to functional responses. The gram negative bacterial product lipopolysaccharide (LPS) is especially potent at driving metabolic reprogramming, enhancing glycolysis and altering the Krebs cycle. Here we describe a role for the citrate-derived metabolite malonyl-CoA in the effect of LPS in macrophages. Malonylation of a wide variety of proteins occurs in response to LPS. We focused on one of these, glyceraldehyde-3-phosphate dehydrogenase (GAPDH). In resting macrophages, GAPDH binds to and suppresses translation of several inflammatory mRNAs, including that encoding TNFα. Upon LPS stimulation, GAPDH undergoes malonylation on lysine 213, leading to its dissociation from TNFα mRNA, promoting translation. We therefore identify for the first time malonylation as a signal, regulating GAPDH mRNA binding to promote inflammation

Molecular definition of group 1 innate lymphoid cells in the mouse uterus

Determining the function of uterine lymphocytes is challenging because of the rapidly changing nature of the organ in response to sex hormones and, during pregnancy, to the invading fetal trophoblast cells. Here we provide the first genome-wide transcriptome atlas of mouse uterine group 1 innate lymphoid cells (g1 ILCs) at mid-gestation. The composition of g1 ILCs fluctuates throughout reproductive life, with Eomes-veCD49a+ ILC1s dominating before puberty and specifically expanding in second pregnancies, when the expression of CXCR6, a marker of memory cells, is upregulated. Tissue-resident Eomes+CD49a+ NK cells (trNK), which resemble human uterine NK cells, are most abundant during early pregnancy, and showcase gene signatures of responsiveness to TGF-β, connections with trophoblast, epithelial, endothelial and smooth muscle cells, leucocytes, as well as extracellular matrix. Unexpectedly, trNK cells express genes involved in anaerobic glycolysis, lipid metabolism, iron transport, protein ubiquitination, and recognition of microbial molecular patterns. Conventional NK cells expand late in gestation and may engage in crosstalk with trNK cells involving IL-18 and IFN-γ. These results identify trNK cells as the cellular hub of uterine g1 ILCs at mid-gestation and mark CXCR6+ ILC1s as potential memory cells of pregnancy.This work was funded by a Wellcome Trust Investigator Award 200841/Z/16/Z, the Centre for Trophoblast Research (CTR), and the Cambridge NIHR BRC Cell Phenotyping Hub to FC, the Associazione Italiana Ricerca per la Ricerca sul Cancro (AIRC) - Special Project 5x1000 no. 9962, AIRC IG 2017 Id.19920 and AIRC 2014 Id. 15283 to LM, and Ministero della Salute RF-2013, GR-2013-02356568 to PV. IF was funded by a CTR PhD fellowship

Risk of chronic kidney disease after cancer nephrectomy.

The incidence of early stage renal cell carcinoma (RCC) is increasing and observational studies have shown equivalent oncological outcomes of partial versus radical nephrectomy for stage I tumours. Population studies suggest that compared with radical nephrectomy, partial nephrectomy is associated with decreased mortality and a lower rate of postoperative decline in kidney function. However, rates of chronic kidney disease (CKD) in patients who have undergone nephrectomy might be higher than in the general population. The risks of new-onset or accelerated CKD and worsened survival after nephrectomy might be linked, as kidney insufficiency is a risk factor for cardiovascular disease and mortality. Nephron-sparing approaches have, therefore, been proposed as the standard of care for patients with type 1a tumours and as a viable option for those with type 1b tumours. However, prospective data on the incidence of de novo and accelerated CKD after cancer nephrectomy is lacking, and the only randomized trial to date was closed prematurely. Intrinsic abnormalities in non-neoplastic kidney parenchyma and comorbid conditions (including diabetes mellitus and hypertension) might increase the risks of CKD and RCC. More research is needed to better understand the risk of CKD post-nephrectomy, to develop and validate predictive scores for risk-stratification, and to optimize patient management

C. elegans Germ Cells Show Temperature and Age-Dependent Expression of Cer1, a Gypsy/Ty3-Related Retrotransposon

Virus-like particles (VLPs) have not been observed in Caenorhabditis germ cells, although nematode genomes contain low numbers of retrotransposon and retroviral sequences. We used electron microscopy to search for VLPs in various wild strains of Caenorhabditis, and observed very rare candidate VLPs in some strains, including the standard laboratory strain of C. elegans, N2. We identified the N2 VLPs as capsids produced by Cer1, a retrotransposon in the Gypsy/Ty3 family of retroviruses/retrotransposons. Cer1 expression is age and temperature dependent, with abundant expression at 15°C and no detectable expression at 25°C, explaining how VLPs escaped detection in previous studies. Similar age and temperature-dependent expression of Cer1 retrotransposons was observed for several other wild strains, indicating that these properties are common, if not integral, features of this retroelement. Retrotransposons, in contrast to DNA transposons, have a cytoplasmic stage in replication, and those that infect non-dividing cells must pass their genomic material through nuclear pores. In most C. elegans germ cells, nuclear pores are largely covered by germline-specific organelles called P granules. Our results suggest that Cer1 capsids target meiotic germ cells exiting pachytene, when free nuclear pores are added to the nuclear envelope and existing P granules begin to be removed. In pachytene germ cells, Cer1 capsids concentrate away from nuclei on a subset of microtubules that are exceptionally resistant to microtubule inhibitors; the capsids can aggregate these stable microtubules in older adults, which exhibit a temperature-dependent decrease in egg viability. When germ cells exit pachytene, the stable microtubules disappear and capsids redistribute close to nuclei that have P granule-free nuclear pores. This redistribution is microtubule dependent, suggesting that capsids that are released from stable microtubules transfer onto new, dynamic microtubules to track toward nuclei. These studies introduce C. elegans as a model to study the interplay between retroelements and germ cell biology