Pratiques de monitorage et de traitement au cours du choc cardiogène: implications pronostiques

Etat des connaissances et question posée. Le choc cardiogène est consécutif à la défaillance primaire de la fonction cardiaque, en présence d'un volume intravasculaire adéquat, induisant une réduction brusque et sévère du débit cardiaque et une oxygénation cellulaire insuffisante. L'étiologie principale du choc cardiogène est l'ischémie myocardique. En dépit de sa prise en charge urgente en milieu de soins intensifs, le choc cardiogène est grevé d'une mortalité de l'ordre de 50%. Le traitement de ce syndrome comporte une optimalisation de la précharge cardiaque (traitement volumique) et l'administration d'agents vasoactifs, agissant sur la contractilité myocardique (médicaments inotropes) et les résistances vasculaires (médicaments vasopresseurs et vasodilatateurs). Les données de l'hémodynamique des patients en choc cardiogène peuvent être monitorées par un cathéter artériel pulmonaire, qui renseigne sur le débit cardiaque et les pressions de remplissage des ventricules, notamment la pression pulmonaire d'occlusion (PAPO), reflet de la précharge du ventricule gauche. A l'heure actuelle, au vu de l'absence d'études prospectives de bonne qualité, il n'existe pas de standard en termes de traitement et de monitorage au cours du choc cardiogène. Dans le présent travail, nous avons voulu déterminer les pratiques en vigueur dans le service de médecine intensive du CHUV concernant le monitorage et le traitement du choc cardiogène, et avons cherché si des déterminants pronostiques pouvaient être individualisés. Méthode. Etude rétrospective portant sur tous les malades admis dans le service de médecine intensive du CHUV pour diagnostic primaire de choc cardiogène sur la période 2010-2011. De nombreuses données démographiques, cliniques, biologiques, hémodynamiques et de traitement ont été recueillies à l'admission et pour une période de 48 heures. Au plan statistique, les données ont été évaluées afin de comparer les populations de patients survivants et non survivants, de même que les populations de patients bénéficiant ou non d'un monitorage invasif. Des méthodes statistiques univariées ont été tout d'abord appliquées, puis nous avons construit un modèle d'analyse multivariée par régression logistique afin d'évaluer l'influence possible de certaines variables explicatives sur le pronostic ou sur l'introduction d'un monitorage invasif. Résultats. Un total de 101 malades a été inclus, majoritairement de sexe masculin (74%) et avec une étiologie ischémique dans 63% des cas. Une proportion de 68% des malades ont bénéficié d'un monitorage hémodynamique invasif. Les patients décédés ont présenté des signes de défaillance cardiaque plus marqués, principalement sous la forme d'une PAPO nettement plus élevée de manière persistante, et dans une moindre mesure, d'un index cardiaque transitoirement plus bas. Les patients non survivants ont reçu davantage de médicaments à effet presseur (noradrénaline, adrénaline, vasopressine), moins de dobutamine et ont eu des bilans hydriques plus positifs au cours des premières 24 heures. En analyse multivariée, seul le score de gravité SAPS II et la présence ou non d'un monitorage, ont été corrélés de manière indépendante à la survie. En revanche, l'âge, la pression artérielle et le degré d'acidose lactique à l'admission n'ont pas été corrélés au pronostic. Concernant le monitoarge, le seul prédicteur indépendant associé à sa mise en place était un âge plus jeune du patient. Conclusions. Nos observations suggèrent qu'un monitorage invasif de la fonction cardiaque,en permettant la détection précoce d'une élévation de la PAPO, permettrait d'orienter le traitement en réduisant les médicaments à effet vasopresseur prédominant au profit de la dobutamine et à réduire les bilans hydriques, ce qui pourrait conduire à améliorer la survie des malades. Ces données sont nouvelles, car elles impliquent une relation directe entre le monitorage et le pronostic, qui n'a pas été formellement rapportée jusqu'ici. Un tel résultat devrait être validé dès que possible dans une étude prospective

Occurrence and fate of micro- and nanoplastic in the terrestrial environment

The worldwide production of plastic has grown exponentially since the 1950’s and revolutionized our daily life. Simultaneously, plastic pollution in the environment has become a global issue and micro- (MP) and nanoplastics (NP) have now been detected even in the most remote ecosystems. There is currently a data gap due to a lack of analytical methods on the occurrence and characterisation of two highly relevant categories of plastic in the soil environment: tire wear particles (TWP), which concentration in the environment is expected to be high and carry toxic additives, and NP, which toxicity has been demonstrated on soil organisms and is characterized by its ability to cross cell membranes. The effects of micro- and nanoplastic (MNP) on their surrounding environment are determined by their size, morphology, surface characteristics and chemical composition, which can be affected by soil residence time. As the soil is often considered as sink for MNP, it is crucial to investigate and understand the different weathering factors which might affect the MNP properties. To address these knowledge gaps, three main objectives were identified in the scope of this study: develop an extraction and single particle identification method for the quantification and characterisation of (i) TWP and (ii) NP in soil samples and (iii) characterise the physico-chemical properties at the surface of plastic debris occurring in the soil environment, as well as assess the effect of soil and UV weathering as single ageing factors. In order to realise the first objective, a method of extraction and identification of TWP in soil samples based on their black colour was developed using optical microscopy. Cryo-grinded TWP down to a size of 35 μm could be detected with a >85% but the tests conducted with environmental TWP showed that the density used in this study was not efficient to separate the whole range of TWP occurring in different densities. Yet, TWP concentration in highway adjacent soil samples ranged between 8084 ±1059 and 2562 ± 1160 TWP kg-1 dry soil and showed similar trends and magnitude order than previously reported concentrations. Thus, the developed protocol was estimated sufficiently accurate for TWP monitoring in soil samples. Regarding the second objective, an extraction and identification method for NP in soil samples was developed using X-ray spectro-microscopy (STX-NEXAFS). The results demonstrated the suitability of the technique for the imaging and chemical characterisation of individual NP with a minimum dimension of ≈100 nm and its application to the analysis of pure NP and for NP present in environmental and food matrices. However, it was not possible to obtain quantitative data on the NP present in the samples, as the method was too time consuming to allow the measurement of a high number of particles. For the last objective, STXM-NEXAFS was applied to the characterisation of the surface alterations of natural-soil weathered, soil-incubated and UV exposed polymers. A surface alteration on a depth varying between 150 and 1000 nm on could be observed and the analysis of the replicate’s measurement acquired on the same plastic debris highlighted the heterogeneity of the processes affecting polymers surface. The comparison of UV weathered and natural-soil weathered samples showed that the two treatments led to different surface alterations and the absence of surface alteration after one-year soil incubation indicated slow aging of polymers in this medium. Moreover, the very first step of surface fragmentation was observed on a PS fragment, providing an insight on the factors and processes leading to the release of MP and NP in soils. Overall, the present research contributed significantly to the development of innovative methods to characterise MNP in the soil environment. The results obtained helped to provide ground information on the characteristic of environmental MP and NP, which is of high importance to design ecotoxicological test using environmentally relevant material as well as validate predictive models to better understand the potential risk that MP and NP represent for the ecosystems

Mechanisms of Allergen-Antibody Interaction of Cockroach Allergen Bla g 2 with Monoclonal Antibodies That Inhibit IgE Antibody Binding

BACKGROUND: Cockroach allergy is strongly associated with asthma, and involves the production of IgE antibodies against inhaled allergens. Reports of conformational epitopes on inhaled allergens are limited. The conformational epitopes for two specific monoclonal antibodies (mAb) that interfere with IgE antibody binding were identified by X-ray crystallography on opposite sites of the quasi-symmetrical cockroach allergen Bla g 2. METHODOLOGY/PRINCIPAL FINDINGS: Mutational analysis of selected residues in both epitopes was performed based on the X-ray crystal structures of the allergen with mAb Fab/Fab' fragments, to investigate the structural basis of allergen-antibody interactions. The epitopes of Bla g 2 for the mAb 7C11 or 4C3 were mutated, and the mutants were analyzed by SDS-PAGE, circular dichroism, and/or mass spectrometry. Mutants were tested for mAb and IgE antibody binding by ELISA and fluorescent multiplex array. Single or multiple mutations of five residues from both epitopes resulted in almost complete loss of mAb binding, without affecting the overall folding of the allergen. Preventing glycosylation by mutation N268Q reduced IgE binding, indicating a role of carbohydrates in the interaction. Cation-π interactions, as well as electrostatic and hydrophobic interactions, were important for mAb and IgE antibody binding. Quantitative differences in the effects of mutations on IgE antibody binding were observed, suggesting heterogeneity in epitope recognition among cockroach allergic patients. CONCLUSIONS/SIGNIFICANCE: Analysis by site-directed mutagenesis of epitopes identified by X-ray crystallography revealed an overlap between monoclonal and IgE antibody binding sites and provided insight into the B cell repertoire to Bla g 2 and the mechanisms of allergen-antibody recognition, including involvement of carbohydrates

Microplastics in agricultural drainage water: A link between terrestrial and aquatic microplastic pollution

Microplastic (MP) contamination has been reported to be higher in terrestrial compared to aquatic environments. This is probably due to the fact that plastic items are mostly produced and used in terrestrial environments and have a longer residence time. However, there are several links between the terrestrial and aquatic environments. We analyzed drainage water samples from agricultural soils in the Seeland, a heavily drained agriculturally intensive area in Switzerland for its MP (>100 μm) concentration and composition. We foundMP in relevant numbers (mean 10.5 ± 9.5 N L−1). The polymers were mainly PA and PE, and the size distribution showed an exponential increase with decreasing particle size. The results show considerableMP concentrations in drainage water and imply a transport of MP in soils down to the drainage pipes. Given the large areas drained both in Switzerland and globally, it is proposed that MP leaching from soil can be a significant source of MP to aquatic ecosystems. Such a contribution should be considered when dealing with MP cycling on a local to global scale

Identification and characterisation of individual nanoplastics by scanning transmission X-ray microscopy (STXM)

Nanoplastics (NP) are of environmental and human health concern. We tested a novel NP extraction method and scanning transmission X-ray spectro-microscopy (STXM) in combination with near-edge X-ray absorption finestructure spectroscopy (NEXAFS) to image and identify individual NP in environmental and food matrices. We (1) discussed the potential of STXM compared to other methods potentially suitable for NP analysis, (2) applied the method on NP suspensions of eight of the most common polymers, (3) analyzed environmental water and soil samples spiked with NP and (4) characterized NP in tea water infused in plastic teabags and unspiked soil samples. Here we show that STXM has methodological advantages and that polymers give characteristic spectra, which allows NP identification in environmental and food matrices. For soils we deliver a visual and spectroscopic characterization of NP, proving their presence and highlighting their diversity. Thus, STXM, can be used for the detection and characterisation of NP in different types of matrices

Immunoglobulin E reactivity and allergenic potency of Morus papyrifera (paper mulberry) pollen

Contains fulltext : 144000.pdf (publisher's version ) (Open Access)BACKGROUND: Paper mulberry (Morus papyrifera) pollen is considered to be one of the most clinically relevant aeroallergens in Pakistan. To date, the allergenicity of the pollen has not been investigated. OBJECTIVE: To characterize the sensitization profile of mulberry-allergic patients and the proteins of paper mulberry pollen contributing to pollinosis in the Pakistani population. METHODS: Proteins were extracted from mulberry pollen using different protocols. Immunoglobulin (Ig) E binding proteins to mulberry pollen was determined by ImmunoCAP testing and immunoblotting using sera from 29 mulberry pollen-allergic patients with positive skin prick test results to mulberry pollen antigens. The histamine release assay was performed in vitro to determine the allergenic potency of pollen extracts and a partially purified mulberry pollen allergen. The protein was identified using N-terminal sequencing and matrix-assisted laser desorption/ionization-time of flight spectrometry (MALDI-TOF/TOF). RESULTS: IgE sensitization to mulberry pollen was confirmed by positive ImmunoCAP results to pollen from Morus alba (white mulberry) in 23 out of 29 mulberry pollen-allergic patients. A 10-kDa protein from the paper mulberry pollen extract was considered a major allergen, along with additional IgE-reactive proteins. Sera from 79% of the patients reacted to the 10-kDa allergen, which showed substantial capacity to trigger histamine release in 3 out of 4 patients. N-terminal sequencing and MALDI-TOF/TOF yielded an amino acid sequence with no homology to known proteins. CONCLUSIONS: Mulberry-allergic patients are sensitized to multiple mulberry pollen allergens. We identified a novel 10-kDa protein that was a major allergen and should be further investigated for diagnostic and therapeutic purposes

Gabriel Fauré : [Compositeur français]

Appartient à l’ensemble documentaire : BNUStr003Appartient à l’ensemble documentaire : BNUStras

Reverse osmosis and ultrafiltration of sweet whey

Methodol. equipment design, and cost ests. are given for the ultrafiltration and reverse osmosis of sweet whey. Calcns. showed that optimum results are obtained when the whey is concd. to 18% solids at the site of whey prodn., and then shipping the conc. to a central location for protein recovery. [on SciFinder (R)