Le polystyrène sulfonate de sodium est une résine échangeuse de cations, utilisée pour le traitement des hyperkaliémies. Parmi les effets secondaires connus, les complications digestives notamment ...coliques ont été décrites dans la littérature chez les insuffisants rénaux dialysés et les transplantés. Nous rapportons deux cas de colites associées à la prise de Kayexalate®, dont une péritonite stercorale ayant conduit à un décès.
Observation 1 Un patient de 80 ans greffé rénal sous warfarine pour une ACFA est hospitalisé fin 2021 pour douleur en fosse iliaque gauche et syndrome inflammatoire biologique, sans fièvre avec un INR dans la zone cible. Le scanner abdomino-pelvien initial retrouve un hématome de 7×4cm au contact du côlon gauche sans syndrome occlusif. Le scanner réalisé à J7 retrouve une majoration en taille de l’hématome et la présence de bulles d’air évoquant une surinfection. La prise en charge a consisté à une suspension de l’anticoagulation et une antibiothérapie pour une durée 21jours. Le contrôle scannographique à J23 retrouve une diminution en taille de l’hématome malgré la persistance des douleurs abdominales. La coloscopie réalisée à distance révèle une lésion supra-centimétrique ulcérée Paris IIc suspecte saignant au contact. L’analyse histologique conclut à une absence de malignité mais identifie des cristaux de polystyrène sulfonate de sodium en surface. L’évolution des douleurs abdominales a été favorable sous traitement symptomatique.
Observation 2 Un patient de 79 ans ayant comme antécédents une HTA, un diabète de type 2, une insuffisance rénale terminale dialysée est hospitalisé 12jours en réanimation pour choc septique d’étiologie indéterminée, évoluant favorablement après une bi-antibiothérapie probabiliste. Peu de temps après son admission en Médecine Interne, le patient présente une défense abdominale associée à une chute tensionnelle persistante malgré le remplissage. Le scanner thoraco-abdomino-pelvien réalisé en urgence retrouve une péritonite en lien avec une perforation du cæcum. En état de choc, le patient est pris en charge en urgence au bloc opératoire. Les constatations peropératoires retrouvent un cæcum perforé avec péritonite stercorale, nécessitant un lavage péritonéal de grande abondance. Le patient est transféré en réanimation au décours du geste opératoire. Le compte rendu anatomopathologique objective au niveau du cæcum une perforation en regard des lésions de nécrose et d’ulcération, et la présence des cristaux de Kayexalate® sans signe de malignité. Le diagnostic évoqué de colopathie au Kayexalate®, nous permet de rapporter le choc septique à une translocation bactérienne non documentée sur un cæcum ulcéré, compliqué d’une péritonite stercorale, d’évolution défavorable ayant conduit au décès du patient.
Les lésions iléo-coliques dues au Kayexalate® surviennent chez 1 % des patients traités par cette résine et sont sous-estimées en raison de méconnaissance de cet effet secondaire 1. La physiopathologie précise n’est pas encore élucidée. Le diagnostic positif est histologique (présence des cristaux de Kayexalate®). Les principaux diagnostics différentiels sont les colites infectieuses, ischémiques, médicamenteuses principalement les anti-inflammatoires non-stéroïdiens et les maladies inflammatoires chroniques de l’intestin. Le pronostic dépend de l’organe atteint, de l’étendue et de la profondeur des lésions. Dans les formes les plus graves, une nécrose colique étendue peut survenir avec une mortalité de 36 % 2. Il n’y a pas de traitement spécifique ; la prise en charge consiste à l’arrêt de polystyrène sulfonate de sodium et dans les formes graves, la résection chirurgicale. Une alternative thérapeutique contre l’hyperkaliémie repose sur le patiromer sorbitex de calcium, qui est une nouvelle résine échangeuse de cations qui augmente l’excrétion fécale du potassium.
Le diagnostic de colite liée au Kayexalate® doit être évoqué chez les patients insuffisants rénaux recevant cette résine devant des symptômes digestifs.
•Different green configurations can be represented by a reservoir cascade model.•The large dissemination of green roof can avoid some flooding issues.•At the basin scale, green roof thickness is not ...a key parameter.•The green roof response depends on initial conditions and rainfall characterization.
At the building scale, the use of green roof has shown a positive impact on urban runoff (decrease and slow-down in peak discharge, decrease in runoff volume). The present work aims to study whether similar effects are possible at the basin scale and what is the minimum spreading of green runoff needed to observe significant impacts. It is particularly focused on the circumstances of such impacts and how they can contribute to storm water management in urban environment. Based on observations on experimental green roofs, a conceptual model has been developed and integrated into the SWMM urban rainfall-runoff model to reproduce the hydrological behaviour of two different types of green roof. It has been combined with a method defining green roofing scenarios by estimating the maximum roof area that can be covered.
This methodology has been applied on a long time series (18years) to the Châtillon urban basin (Haut-de-Seine county, France) frequently affected by urban flooding. For comparison, the same methodology has been applied at the building scale and a complementary analysis has been conducted to study which hydrometeorological variables may affect the magnitude of these hydrological impacts at both scales.
The results show green roofs, when they are widely implemented, can affect urban runoff in terms of peak discharge and volume, and avoid flooding in several cases. Both precipitation – generally accumulated during the whole event- and the initial substrate saturation are likely to have an impact on green roof effects. In this context, the studied green roofs seem useful to mitigate the effects of usual rainfall events but turn out being less helpful for the more severe ones. We conclude that, combined with other infrastructures, green roofs represent an interesting contribution to urban water management in the future.
In flash flood prone areas, roads are often the first assets affected by inundations which make rescue operations difficult and represent a major threat to lives: almost half of the victims are car ...passengers trapped by floods. In the past years, the Gard region (France) road management services have realized an extensive inventory of the known road submersions that occurred during the last 40 years. This inventory provided an unique opportunity to analyse the causes of road flooding in an area frequently affected by severe flash floods. It will be used to develop a road submersion susceptibility rating method, representing the first element of a road warning system. This paper presents the results of the analysis of this data set. A companion paper will show how the proposed road susceptibility rating method can be combined with distributed rainfall-runoff simulations to provide accurate road submersion risk maps. The very low correlation between the various possible explanatory factors and the susceptibility to flooding measured by the number of past observed submersions implied the use of particular statistical analysis methods based on the general principals of the discriminant analysis. The analysis led to the definition of four susceptibility classes for river crossing road sections. Validation tests confirmed that this classification is robust, at least in the considered area. One major outcome of the analysis is that the susceptibility to flooding is rather linked to the location of the road sections than to the size of the river crossing structure (bridge or culvert).
Climate change may have significant consequences for water resources availability and management at the basin scale. This is particularly true for areas already suffering from water stress, such as ...the Mediterranean area. This work focused on studying these impacts in the Llobregat basin supplying the Barcelona region. Several climate projections, adapted to the spatiotemporal resolution of the study, were combined with a daily hydrological model to estimate future water availability. Depending on the scenario and the time period, different assessment indicators such as reliability and resilience showed a future decrease in water resources (up to 40%), with drought periods becoming more frequent. An additional uncertainty analysis showed the high variability of the results (annual water availability ranging from 147 hm
3
/year to 274 hm
3
/year), thus making accurate projections difficult. Finally, the study illustrates how climate change could be taken into account to provide adaptive measures for the future.
Editor M.C. Acreman; Associate editor J. Thompson
This paper presents an initial prototype of a distributed hydrological model used to map possible road inundations in a region frequently exposed to severe flash floods: the Gard region (South of ...France). The prototype has been tested in a pseudo real-time mode on five recent flash flood events for which actual road inundations have been inventoried. The results are promising: close to 100% probability of detection of actual inundations, inundations detected before they were reported by the road management field teams with a false alarm ratios not exceeding 30%. This specific case study differs from the standard applications of rainfall-runoff models to produce flood forecasts, focussed on a single or a limited number of gauged river cross sections. It illustrates that, despite their lack of accuracy, hydro-meteorological forecasts based on rainfall-runoff models, especially distributed models, contain valuable information for flood event management. The possible consequences of landslides, debris flows and local erosion processes, sometimes associated with flash floods, were not considered at this stage of development of the prototype. They are limited in the Gard region but should be taken into account in future developments of the approach to implement it efficiently in other areas more exposed to these phenomena such as the Alpine area.
CoFe2-xGdxO4 (x=0, 0.2) thin films of about 70nm thickness were epitaxially grown on (001) MgO substrates using pulsed laser deposition and a controlled O2/N2 deposition pressure within the 0.01-1 ...mbar range. Using Resonant elastic X-Ray scattering (REXS) experiments, we bring the proof that the Gd cations are inserted in the spinel cell. As expected, they mostly occupy the octahedral sites and drive the Co cations towards the tetrahedral ones. However, they also surprisingly partly occupy the tetrahedral sites. Despite the increase of the amount of Co in the tetrahedral sites, the insertion of the rare earth element, globally inflating the volume of the cell, precludes the occurence of the auxetic behavior observed in the undoped samples. The out-of-plane cell parameters indeed never reach values lower than those of the in-plane parameters, fully strained by the MgO substrate. This study brings a new light on the parameters controlling the auxetic behaviour in CFO thin films and demonstrates that the location of the Co cations in the tetrahedral sites is not a sufficient condition.
•Possibility to insert Gd3+ into spinel phase is clearly evidenced•Insertion of Gd3+ into Td sites is proved.•Cationic distribution has been determined for the thin film thanks to resonant x-ray diffraction.•Additional rules of the theoretical model proposed by Fereiro-Vilas is given (i.e. driving the Co cations towards the tetrahedral sites is not a sufficient condition to auxetism)
The effectiveness of the analysis of stable isotope ratios (
13C/
12C and
15N/
14N) in fractions of lamb meat, measured by isotope ratio mass spectrometry, was evaluated as a method of feeding and ...geographical origin authentication. Analyses were carried out on meat from 12 lamb types, produced in couples in six European countries (country of origin, CO) and divided in three groups according to the feeding regime during their finishing period: suckled milk only, pasture without any solid supplementation and supplementation containing maize grain (feeding regime, FR). These analyses were made on two samples of
longissimus thoracis muscle, taken from the 13th rib section of the left side of two different lambs, randomly chosen between the 120 selected to represent each lamb type. δ
13C values varied significantly in different meat fractions, the difference being higher in protein than in fat (average difference 5.0‰). However, the pairs δ
13C values of crude fat and protein were highly correlated (
r=0.976) and affected by lamb type in a similar fashion, mainly reflecting animals’ feeding regime. Even δ
15N values of meat protein fraction showed significant differences between lamb types, not dependant on the feeding regime. In fact, lambs fed on similar diets, but in different countries, gave meat with different
15N relative abundances. These findings provide the possibility of discriminating lamb types within the same feeding regime. Canonical discriminant analysis was carried out to evaluate whether lamb meat from different CO or FR or CO×FR interaction could be mathematically distinguished by its stable isotope ratios. On the basis of CO, the corrected empirical allocation of 79.2% of the initial observations and the corrected cross-validation of two thirds of the individual meat samples was obtained. FR gave better results: 91.7% of the individual meat samples was both correctly allocated and cross-validated, indicating the high potential of stable isotope ratio analysis as a tool for lamb diet characterisation. The most satisfactory classification attained, using K-means clustering technique and canonical discriminant analysis, enabled a good resolution of six CO×FR groups of lamb types: Icelandic fed on pasture; British and French grazing; Italian; suckled and Karagouniko concentrates finished; French Lacaune; Ternasco de Aragon. It was concluded that multielement stable isotope analysis may be considered promising for the reliable evaluation of lamb meat authenticity, in the same way as for wine, fruit juice, honey and dairy products.
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