107 resultados para woodland key habitats


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The aim of our study was to identify and document some key cognitive aptitudes used by ambulance people in emergency situations. Better knowing such aptitudes is necessary for a school of ambulance people in order to improve the selection and education of students. The idea was to better consider real work activity requirements and characteristics, and to develop and implement genuine educational content and selection tools. We followed the work activity of ambulance professionals involved in real emergency situations. Some interventions were filmed and post-analyzed. We completed and validated our analysis by means of interviews with ambulance personnel. We selected some video sequences and used them as a support for the interviews. We identified and documented many different key aptitudes like orientation and spatial sense, the capacity to perform complex cognitive tasks and delicate manipulations in the context of divided attention, as well as diverse aptitudes relevant in collaborative work.

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Besides tumor cells, the tumor microenvironment harbors a variety of host-derived cells, such as endothelial cells, fibroblasts, innate and adaptive immune cells. It is a complex and highly dynamic environment, providing very important cues to tumor development and progression. Tumor-associated endothelial cells play a key role in this process. On the one hand, they form tumor-associated (angiogenic) vessels through sprouting from locally preexisting vessels or recruitment of bone marrow-derived endothelial progenitor cells, to provide nutritional support to the growing tumor. On the other hand, they are the interface between circulating blood cells, tumor cells and the extracellular matrix, thereby playing a central role in controlling leukocyte recruitment, tumor cell behavior and metastasis formation. Hypoxia is a critical parameter modulating the tumor microenvironment and endothelial/tumor cell interactions. Under hypoxic stress, tumor cells produce factors that promote tumor angiogenesis, tumor cell motility and metastasis. Among these factors, VEGF, a main angiogenesis modulator, can also play a critical role in the control of immune tolerance. This review discusses some aspects of the role of endothelial cells within tumor microenvironment and emphasizes their interaction with tumor cells, the extracellular matrix and with immune killer cells. We will also address the role played by circulating endothelial progenitor cells and illustrate their features and mechanism of recruitment to the tumor microenvironment and their role in tumor angiogenesis.

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The appearance of multicellular organisms imposed the development of several mechanisms for cell-to-cell communication, whereby different types of cells coordinate their function. Some of these mechanisms depend on the intercellular diffusion of signal molecules in the extracellular spaces, whereas others require cell-to-cell contact. Among the latter mechanisms, those provided by the proteins of the connexin family are widespread in most tissues. Connexin signaling is achieved via direct exchanges of cytosolic molecules between adjacent cells at gap junctions, for cell-to-cell coupling, and possibly also involves the formation of membrane "hemi-channels," for the extracellular release of cytosolic signals, direct interactions between connexins and other cell proteins, and coordinated influence on the expression of multiple genes. Connexin signaling appears to be an obligatory attribute of all multicellular exocrine and endocrine glands. Specifically, the experimental evidence we review here points to a direct participation of the Cx36 isoform in the function of the insulin-producing β-cells of the endocrine pancreas, and of the Cx40 isoform in the function of the renin-producing juxtaglomerular epithelioid cells of the kidney cortex.

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An attractive treatment of cancer consists in inducing tumor-eradicating CD8(+) CTL specific for tumor-associated Ags, such as NY-ESO-1 (ESO), a strongly immunogenic cancer germ line gene-encoded tumor-associated Ag, widely expressed on diverse tumors. To establish optimal priming of ESO-specific CTL and to define critical vaccine variables and mechanisms, we used HLA-A2/DR1 H-2(-/-) transgenic mice and sequential immunization with immunodominant DR1- and A2-restricted ESO peptides. Immunization of mice first with the DR1-restricted ESO(123-137) peptide and subsequently with mature dendritic cells (DCs) presenting this and the A2-restriced ESO(157-165) epitope generated abundant, circulating, high-avidity primary and memory CD8(+) T cells that efficiently killed A2/ESO(157-165)(+) tumor cells. This prime boost regimen was superior to other vaccine regimes and required strong Th1 cell responses, copresentation of MHC class I and MHC class II peptides by the same DC, and resulted in upregulation of sphingosine 1-phosphate receptor 1, and thus egress of freshly primed CD8(+) T cells from the draining lymph nodes into circulation. This well-defined system allowed detailed mechanistic analysis, which revealed that 1) the Th1 cytokines IFN-gamma and IL-2 played key roles in CTL priming, namely by upregulating on naive CD8(+) T cells the chemokine receptor CCR5; 2) the inflammatory chemokines CCL4 (MIP-1beta) and CCL3 (MIP-1alpha) chemoattracted primed CD4(+) T cells to mature DCs and activated, naive CD8(+) T cells to DC-CD4 conjugates, respectively; and 3) blockade of these chemokines or their common receptor CCR5 ablated priming of CD8(+) T cells and upregulation of sphingosine 1-phosphate receptor 1. These findings provide new opportunities for improving T cell cancer vaccines.

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PURPOSE: To improve the risk stratification of patients with rhabdomyosarcoma (RMS) through the use of clinical and molecular biologic data. PATIENTS AND METHODS: Two independent data sets of gene-expression profiling for 124 and 101 patients with RMS were used to derive prognostic gene signatures by using a meta-analysis. These and a previously published metagene signature were evaluated by using cross validation analyses. A combined clinical and molecular risk-stratification scheme that incorporated the PAX3/FOXO1 fusion gene status was derived from 287 patients with RMS and evaluated. RESULTS: We showed that our prognostic gene-expression signature and the one previously published performed well with reproducible and significant effects. However, their effect was reduced when cross validated or tested in independent data and did not add new prognostic information over the fusion gene status, which is simpler to assay. Among nonmetastatic patients, patients who were PAX3/FOXO1 positive had a significantly poorer outcome compared with both alveolar-negative and PAX7/FOXO1-positive patients. Furthermore, a new clinicomolecular risk score that incorporated fusion gene status (negative and PAX3/FOXO1 and PAX7/FOXO1 positive), Intergroup Rhabdomyosarcoma Study TNM stage, and age showed a significant increase in performance over the current risk-stratification scheme. CONCLUSION: Gene signatures can improve current stratification of patients with RMS but will require complex assays to be developed and extensive validation before clinical application. A significant majority of their prognostic value was encapsulated by the fusion gene status. A continuous risk score derived from the combination of clinical parameters with the presence or absence of PAX3/FOXO1 represents a robust approach to improving current risk-adapted therapy for RMS.

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Résumé : Ce travail comprend deux parties : La première partie a pour but de présenter une revue des techniques de gastrostomie chez l'enfant. La gastrostomie est, par définition, un tractus fistuleux entre l'estomac et la paroi abdominale. Le but de la gastrostomie est de permettre la décompression gastrique, la nutrition entérale et l'apport médicamenteux. Les indications et contre-indications à la confection et utilisation de la gastrostomie sont détaillées dans ce travail. Historiquement, les premières gastrostomies étaient d'origine accidentelle ou infectieuse (fistule gastro-cutanée), incompatibles avec la vie. Sedillot, en 1845 décrivit la première gastrostomie chirurgicale sans cathéter, qui avait comme désavantage la présence de fuites. Depuis, les techniques se sont multipliées en évoluant vers la continence et l'utilisation de cathéters. En 1979 Gauderer décrivit pour la première fois une technique percutanée, réalisée sur un enfant âgé de 5 mois. Cette technique est appelée « Percutaneous Endoscopic Gastrostomy » (PEG). Elle a ensuite été élargie à la population adulte. Actuellement, il existe une grande multiplicité de techniques par abord « laparotomique », laparoscopique ou percutanée (endoscopique ou radiologique). Ces techniques peuvent être combinées. Toutes ces techniques nécessitent la présence intermittente ou continue d'un dispositif, qui permet le maintient de la gastrostomie ouverte et évite les fuites gastriques. Ces dispositifs sont multiples; initialement il s'agissait de cathéters rigides (bois, métal, caoutchouc). Ensuite ils ont été fabriqués en silicone, ce qui les rend plus souples et mieux tolérés par le patient. Pour éviter leur dislocation, ils possèdent un système d'amarrage intra-gastrique tel que : un champignon (Bard®), un ballonnet (Foley®, Mic-Key®), ou une forme spiralée du cathéter (« pig-tail ») et possèdent un système d'amarrage extra-gastrique (« cross-bar »). En 1982, Gauderer créa le premier dispositif à fleur de peau : le bouton de gastrostomie (BG). Actuellement, il en existe deux types : à champignon (Bard®) et à ballonnet (Mic-Key®). Il existe plusieurs types de complications liées à la technique opératoire, à la prise en charge et au matériel utilisé. Une comparaison des différentes techniques, matériaux utilisés et coûts engendrés est détaillée dans ce travail. La deuxième partie de ce travail est dédiée aux BG et plus spécifiquement au BG à ballonnet (Mic-Key®). Nous présentons les différents boutons et les techniques spécifiques. Le BG est inséré soit dans une gastrostomie préformée, soit directement lors de la confection d'une gastrostomie par laparotomie, laparoscopie ou de façon percutanée. Les complications liées au BG sont rapportées. D'autres utilisations digestives ou urologiques sont décrites. Nous présentons ensuite notre expérience avec 513 BG à ballonnet (Mic-Key®) dans une revue de 73 enfants. La pose du BG est effectuée dans une gastrostomie préformée sans recours à une anesthésie générale. La technique choisie pour la confection de la gastrostomie dépend de la pathologie de base, de l'état général du patient, de la nécessité d'une opération concomitante et du risque anesthésique. Nous apportons des précisions sur le BG telles que la dimension en fonction de l'âge, la durée de vie, et les causes qui ont amené au changement du BG. Nos résultats sont comparés à ceux de la littérature. Sur la base de notre expérience et après avoir passé en revue la littérature spécialisée, nous proposons des recommandations sur le choix de la technique et le choix du matériel. Ce travail se termine avec une réflexion sur le devenir de la gastrostomie. Si le futur consiste à améliorer et innover les techniques et les matériaux, des protocoles destinés à la standardisation des techniques, à la sélection des patients et à l'enseignement des soins devraient s'en suivre. La prise en charge de l'enfant ne se limite pas à la sélection appropriée de la technique et des matériaux, mais il s'agit avant tout d'une approche multidisciplinaire. La collaboration entre le personnel soignant, la famille et l'enfant est essentielle pour que la prise en charge soit optimale et sans risques.

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Poly (ADP-ribose) polymerase 1 (PARP-1) is a constitutive enzyme, the major isoform of the PARP family, which is involved in the regulation of DNA repair, cell death, metabolism, and inflammatory responses. Pharmacological inhibitors of PARP provide significant therapeutic benefits in various preclinical disease models associated with tissue injury and inflammation. However, our understanding the role of PARP activation in the pathophysiology of liver inflammation and fibrosis is limited. In this study we investigated the role of PARP-1 in liver inflammation and fibrosis using acute and chronic models of carbon tetrachloride (CCl4 )-induced liver injury and fibrosis, a model of bile duct ligation (BDL)-induced hepatic fibrosis in vivo, and isolated liver-derived cells ex vivo. Pharmacological inhibition of PARP with structurally distinct inhibitors or genetic deletion of PARP-1 markedly attenuated CCl4 -induced hepatocyte death, inflammation, and fibrosis. Interestingly, the chronic CCl4 -induced liver injury was also characterized by mitochondrial dysfunction and dysregulation of numerous genes involved in metabolism. Most of these pathological changes were attenuated by PARP inhibitors. PARP inhibition not only prevented CCl4 -induced chronic liver inflammation and fibrosis, but was also able to reverse these pathological processes. PARP inhibitors also attenuated the development of BDL-induced hepatic fibrosis in mice. In liver biopsies of subjects with alcoholic or hepatitis B-induced cirrhosis, increased nitrative stress and PARP activation was noted. CONCLUSION: The reactive oxygen/nitrogen species-PARP pathway plays a pathogenetic role in the development of liver inflammation, metabolism, and fibrosis. PARP inhibitors are currently in clinical trials for oncological indications, and the current results indicate that liver inflammation and liver fibrosis may be additional clinical indications where PARP inhibition may be of translational potential.

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PURPOSE: The purpose of this study was to reach an international consensus to determine what key elements should be part of a transition program and what indicators could be used to assess its success. METHODS: For this purpose, a Delphi study including an international panel of 37 experts was carried out. The study consisted of three rounds, with response rates ranging from 86.5% to 95%. At each round, experts were asked to assess key elements (defined as the most important elements for the task) and indicators (defined as quantifiable characteristics). At each round, panelists were contacted via e-mail explaining them the tasks to be done and giving them the Web link where to complete the questionnaire. At Round 3, each key element and indicator was assessed as essential, very important, important, accessory, or unnecessary. A 70% agreement was used as cutoff. RESULTS: At Round 3, more than 70% of panelists agreed on six key elements being essential, with one of them (Assuring a good coordination between pediatric and adult professionals) reaching an almost complete consensus (97%). Additionally, 11 more obtained more than 70% agreement when combined with the Very important category. Among indicators, only one (Patient not lost to follow-up) was considered almost unanimously (91%) as essential by the panelists and seven others also reached consensus when the Very important category was included. CONCLUSIONS: Using these results as a framework to develop guidelines at local, national, and international levels would allow better assessing and comparing transition programs.

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Crassulacean acid metabolism (CAM) photosynthesis is an adaptation to water and atmospheric CO2 deficits that has been linked to diversification in dry-adapted plants. We investigated whether CAM evolution can be associated with the availability of new or alternative niches, using Eulophiinae orchids as a case study. Carbon isotope ratios, geographical and climate data, fossil records and DNA sequences were used to: assess the prevalence of CAM in Eulophiinae orchids; characterize the ecological niche of extant taxa; infer divergence times; and estimate whether CAM is associated with niche shifts. CAM evolved in four terrestrial lineages during the late Miocene/Pliocene, which have uneven diversification patterns. These lineages originated in humid habitats and colonized dry/seasonally dry environments in Africa and Madagascar. Additional key features (variegation, heterophylly) evolved in the most species-rich CAM lineages. Dry habitats were also colonized by a lineage that includes putative mycoheterotrophic taxa. These findings indicate that the switch to CAM is associated with environmental change. With its suite of adaptive traits, this group of orchids represents a unique opportunity to study the adaptations to dry environments, especially in the face of projected global aridification.

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Our aim is to describe the acute effects of catecholamines/β-adrenergic agonists on contraction of non-fatigued skeletal muscle in animals and humans, and explain the mechanisms involved. Adrenaline/β-agonists (0.1-30 μm) generally augment peak force across animal species (positive inotropic effect) and abbreviate relaxation of slow-twitch muscles (positive lusitropic effect). A peak force reduction also occurs in slow-twitch muscles in some conditions. β2 -Adrenoceptor stimulation activates distinct cyclic AMP-dependent protein kinases to phosphorylate multiple target proteins. β-Agonists modulate sarcolemmal processes (increased resting membrane potential and action potential amplitude) via enhanced Na(+) -K(+) pump and Na(+) -K(+) -2Cl(-) cotransporter function, but this does not increase force. Myofibrillar Ca(2+) sensitivity and maximum Ca(2+) -activated force are unchanged. All force potentiation involves amplified myoplasmic Ca(2+) transients consequent to increased Ca(2+) release from sarcoplasmic reticulum (SR). This unequivocally requires phosphorylation of SR Ca(2+) release channels/ryanodine receptors (RyR1) which sensitize the Ca(2+) -induced Ca(2+) release mechanism. Enhanced trans-sarcolemmal Ca(2+) influx through phosphorylated voltage-activated Ca(2+) channels contributes to force potentiation in diaphragm and amphibian muscle, but not mammalian limb muscle. Phosphorylation of phospholamban increases SR Ca(2+) pump activity in slow-twitch fibres but does not augment force; this process accelerates relaxation and may depress force. Greater Ca(2+) loading of SR may assist force potentiation in fast-twitch muscle. Some human studies show no significant force potentiation which appears to be related to the β-agonist concentration used. Indeed high-dose β-agonists (∼0.1 μm) enhance SR Ca(2+) -release rates, maximum voluntary contraction strength and peak Wingate power in trained humans. The combined findings can explain how adrenaline/β-agonists influence muscle performance during exercise/stress in humans.