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Search Results: 1 - 10 of 7607 matches for " Philippe Stordeur "
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Variation of inflammatory dynamics and mediators in primiparous cows after intramammary challenge with Escherichia coli
Adel Pezeshki, Philippe Stordeur, Hugues Wallemacq, Frédéric Schynts, Mieke Stevens, Philippe Boutet, Luc J Peelman, Bart De Spiegeleer, Luc Duchateau, Fabrice Bureau, Christian Burvenich
Veterinary Research , 2011, DOI: 10.1186/1297-9716-42-15
Abstract: The severity of coliform mastitis is of much more concern than its incidence [1]. Pathogen, cow and environment are three interdependent factors which influence the mastitis susceptibility [1]. From the various bacterial virulence factors studied during Escherichia coli mastitis [2], only a few have been found to play an important role in the outcome of the disease. It has been accepted that the type of E. coli strain is not the main factor in classification of severity. Preventive treatments which are efficient against contagious mastitis have been shown to be inefficient in the control of E. coli mastitis [3]. The severity of bovine E. coli mastitis is mainly determined by cow factors rather than by the pathogenecity of the invading pathogen and management [1]. It is known that the growth of E. coli in the udder cistern is specially related with the period of lactation and parity of cows. E. coli mastitis with severe clinical symptoms is more frequently observed around calving and during early lactation in dairy cows, whereas symptoms are mild to moderate during mid and late lactation. Because of hormonal, metabolic and nutritional alterations associated with pregnancy, immune system is compromised around calving (reviewed by Pezeshki et al. [4]). Cow parity is another important physiological factor that influences the severity of clinical coliform mastitis [5,6]. Clinical severe cases of coliform mastitis are mostly seen among multiparous cows rather than primiparous cows during early lactation. To our best knowledge the inflammatory status of primiparous cows ranking based on severity after intramammary infection of E. coli is poorly understood during early lactation. Physiological factors have been mainly studied in multiparous cows ranging from second lactation to sixth lactation [6-10].Thromboxanes (TX), prostaglandins (PG), leukotriens (LT) and lipoxines (LX) which are the enzymatically generated products of cyclooxygenases (COX) and lipoxygenases are genera
Cultured Kaposi's sarcoma tumor cells exhibit a chemokine receptor repertoire that does not allow infection by HIV-1
Thierry Simonart, Claire Debussher, Corinne Liesnard, Laurent Debaisieux, Marie-Luce Delforge, Aurore de Lavareille, Philippe Hermans, Jean-Paul Van Vooren, Patrick Stordeur
BMC Dermatology , 2001, DOI: 10.1186/1471-5945-1-2
Abstract: KS-derived cells and KS-Y1 cells were investigated using RT-PCR for the expression of CD4, CCR3, CCR5, CCR8 and CXCR4 mRNA. HIV infectivity of these cells was determined by p24 antigen and HIV-1 RNA production, as well as by HIV-1 DNA integration.With the exception of CCR8 which is expressed by KS-derived spindle cell cultures but not by KS-Y1 cells, unstimulated KS cells express no significant levels of CD4, CCR3, CCR5 or CXCR4 mRNA. HIV infectivity assays showed that KS cells were unpermissive to HTLVIIIB and JRFL strains. Although the expression of CXCR4 mRNA could be upregulated by interleukin-1β, stimulation of KS cells by this cytokine did not allow infection by HIV-1.This shows that KS cells exhibit a chemokine receptor repertoire that does not allow infection by HIV-1. Other cell types making up KS lesions, such as inflammatory cells, are likely to represent the source of HIV-1 products cooperating to promote KS development and progression.Kaposi's sarcoma (KS) is an angioproliferative disease that has aroused considerable interest of late, as it is one of the major tumors found in patients with the acquired immune deficiency syndrome (AIDS). It is histologically characterized by inflammation, prominent angiogenesis and proliferating spindle cells which are considered to be the tumor cells of KS. The pathogenesis of KS is not fully understood. The current hypothesis to explain the initiation and progression of the tumor is a multi-step pathway involving cytokine dysregulation and active infection by human herpesvirus 8 (HHV-8) [1,2,3,4]. The extremely high frequency of KS among HIV-infected patients, together with the particular aggressiveness of AIDS-KS suggests that HIV plays a critical role in KS pathogenesis [3]. Several studies point to the HIV-1 Tat protein synergizing with growth factors to promote the growth of AIDS-KS [5,6]. However, whether HIV can directly infect KS cells is still controversial. Delli Bovi et al. did not detect HIV DNA in KS lesio
Challenges in physician supply planning: the case of Belgium
Sabine Stordeur, Christian Léonard
Human Resources for Health , 2010, DOI: 10.1186/1478-4491-8-28
Abstract: In Belgium, a numerus clausus set up in 1997 and effective in 2004, aims to limit the total number of physicians working in the curative sector. The assumption of a positive relationship between physician densities and health care utilization was a major argument in favor of medical supply restrictions. This new regulation did not improve recurrent challenges such as specialty imbalances, with uncovered needs particularly among general practitioners, and geographical maldistribution. New difficulties also emerged. In particular, limiting national training of HRH turned out to be ineffective within the open European workforce market. The lack of integration of policies affecting HRH was noteworthy. We described in the paper what strategies were developed to address those challenges in Belgium and in neighboring countries.Planning the medical workforce involves determining the numbers, mix, and distribution of health providers that will be required at some identified future point in time. To succeed in their task, health policy planners have to take a broader perspective on the healthcare system. Focusing on numbers is too restrictive and adopting innovative policies learned from benchmarking without integration and coordination is unfruitful. Evolving towards a strategic planning is essential to control the effects of the complex factors impacting on human resources. This evolution requires an effective monitoring of all key factors affecting supply and demand, a dynamic approach, and a system-level perspective, considering all healthcare professionals, and integrating manpower planning with workforce development.To engage in an evidence-based action, policy-makers need a global manpower picture, from their own country and abroad, as well as reliable and comparable manpower databases allowing proper analysis and planning of the workforce.The healthcare sector is labor intensive and human resources represent the most important input into the provision of health care,
Physician supply forecast: better than peering in a crystal ball?
Dominique Roberfroid, Christian Leonard, Sabine Stordeur
Human Resources for Health , 2009, DOI: 10.1186/1478-4491-7-10
Abstract: A literature review was carried out in electronic databases Medline-Ovid, Embase and ERIC. Concrete examples of planning experiences in various countries were analysed.Four main forecasting approaches were identified. The supply projection approach defines the necessary inflow to maintain or to reach in the future an arbitrary predefined level of service offer. The demand-based approach estimates the quantity of health care services used by the population in the future to project physician requirements. The needs-based approach involves defining and predicting health care deficits so that they can be addressed by an adequate workforce. Benchmarking health systems with similar populations and health profiles is the last approach. These different methods can be combined to perform a gap analysis. The methodological challenges of such projections are numerous: most often static models are used and their uncertainty is not assessed; valid and comprehensive data to feed into the models are often lacking; and a rapidly evolving environment affects the likelihood of projection scenarios. As a result, the internal and external validity of the projections included in our review appeared limited.There is no single accepted approach to forecasting physician requirements. The value of projections lies in their utility in identifying the current and emerging trends to which policy-makers need to respond. A genuine gap analysis, an effective monitoring of key parameters and comprehensive workforce planning are key elements to improving the usefulness of physician supply projections.The health care sector is labour-intensive and human resources are the most important input into the provision of health care, as well as accounting for the largest proportion of health care expenditure [1]. Planning human resources for health is the process of estimating the required health workforce to meet future health service requirements and the development of strategies to meet those requirement
Comment on "Scalings for radiation from plasma bubbles" [Phys. Plasmas 17, 056708 (2010)]
S. Corde,A. Stordeur,V. Malka
Physics , 2011, DOI: 10.1063/1.3566012
Abstract: Thomas has recently derived scaling laws for X-ray radiation from electrons accelerated in plasma bubbles, as well as a threshold for the self-injection of background electrons into the bubble [A. G. R. Thomas, Phys. Plasmas 17, 056708 (2010)]. To obtain this threshold, the equations of motion for a test electron are studied within the frame of the bubble model, where the bubble is described by prescribed electromagnetic fields and has a perfectly spherical shape. The author affirms that any elliptical trajectory of the form x'^2/{\gamma}_p^2 + y'^2 = R^2 is solution of the equations of motion (in the bubble frame), within the approximation p'_y^2/p'_x^2 \ll 1. In addition, he highlights that his result is different from the work of Kostyukov et al. [Phys. Rev. Lett. 103, 175003 (2009)], and explains the error committed by Kostyukov-Nerush-Pukhov-Seredov (KNPS). In this comment, we show that numerically integrated trajectories, based on the same equations than the analytical work of Thomas, lead to a completely different result for the self-injection threshold, the result published by KNPS [Phys. Rev. Lett. 103, 175003 (2009)]. We explain why the analytical analysis of Thomas fails and we provide a discussion based on numerical simulations which show exactly where the difference arises. We also show that the arguments of Thomas concerning the error of KNPS do not hold, and that their analysis is mathematically correct. Finally, we emphasize that if the KNPS threshold is found not to be verified in PIC (Particle In Cell) simulations or experiments, it is due to a deficiency of the model itself, and not to an error in the mathematical derivation.
Large Pore Ion and Metabolite-Permeable Channel Regulation of Postnatal Ventricular Zone Neural Stem and Progenitor Cells: Interplay between Aquaporins, Connexins, and Pannexins?
Leigh E. Wicki-Stordeur,Leigh Anne Swayne
Stem Cells International , 2012, DOI: 10.1155/2012/454180
Abstract: The birth of new neurons from unspecialized neural stem and progenitor cells surrounding the lateral ventricles occurs throughout postnatal life. This process, termed neurogenesis, is complex and multistepped, encompassing several types of cellular behaviours, such as proliferation, differentiation, and migration. These behaviours are influenced by numerous factors present in the unique, permissive microenvironment. A major cellular mechanism for sensing the plethora of environmental cues directing this process is the presence of different channel forming proteins spanning the plasma membrane. So-called large pore membrane channels, which are selective for the passage of specific types of small molecules and ions, are emerging as an important subgroup of channel proteins. Here, we focus on the roles of three such large pore channels, aquaporin 4, connexin 43, and pannexin 1. We highlight both their independent functions as well as the accumulating evidence for crosstalk between them. 1. Introduction New neurons are produced in the ventricular zone (VZ) of the lateral ventricles throughout postnatal life [1]. This is a remarkable developmental process, in which unspecialized neural stem and progenitor cells (NSC/NPCs) pass through a complex gauntlet of cell behaviours, such as proliferation, differentiation, and migration. It is now becoming increasingly clear that the highly controlled movement of several ions and small molecules trigger numerous, complex signaling pathways that underscore the regulation of these behaviours (recently reviewed in [2, 3]). As follows, there is a growing body of evidence implicating “large pore” channels in the control of postnatal VZ neurogenesis. In contrast to typical ion channels, which are selective for small ions, large pore channels can additionally (or exclusively) allow passage of small molecules (neutral or charged). Aquaporin 4 (AQP4) connexin 43 (Cx43), and pannexin 1 (Panx1) are three such large pore channels that are expressed in postnatal VZ. Perhaps not surprisingly the roles of these channels appear to be closely linked with one another and also with the functions of other ion channels in the regulation of postnatal VZ NSC/NPC biology. 2. AQP4 There are thirteen known types of AQPs in mammals (AQP0-12; recently reviewed in [4]). These are categorized into two primary subgroups based on function: those selective solely for water (AQP0, AQP1, AQP2, AQP4, AQP5), and those permeable to water as well as small nonpolar solutes such as glycerol and urea (AQP3, AQP7, AQP9, and AQP10). Additional types can conduct
Team Play in Football: How Science Supports F. C. Barcelona’s Training Strategy  [PDF]
Philippe Chassy
Psychology (PSYCH) , 2013, DOI: 10.4236/psych.2013.49A2002
Abstract:

The paper applies the theory of self-organising systems to sport. The central hypothesis is that team play, implemented as passing in football, is the central factor generating performance. Data from the 2013 European Champions League were used to show that passing speed and precision predict domination (possession), shooting opportunities and performance. By using principal component analysis, the article offers a formula to estimate the team play of any team considering its passing speed, passing precision and ability to score. The compound measure accounts for about 42% of the variance in performance. The impact of this research on the training of football players is discussed.

Inductive Modelling of Vulnerable Sustainability Systems  [PDF]
Philippe Woloszyn
Journal of Service Science and Management (JSSM) , 2015, DOI: 10.4236/jssm.2015.84060
Abstract: Within the context of globalisation, managing territorial resources means overcoming the following problems: difficulty in implementing integrated management processes at various organisation levels; conflicting uses; unadapted decision systems, assymetric information and uneven operative processes in each dimension of sustainable development. To illustrate and overpass those difficulties in a territorial level, we propose to introduce an analogical induction-model to describe both vulnerability situations and associated resilience procedures. The construction of this model is founded on a truly integrated approach, combining the economic, social-cultural, and ecological aspects of territorial vulnerability. Constituted by three passive components as potential energy, kinetic energy, and energy dissipation, this approach assumes that economics are a social extension of a environmental energy system. So we claim that social and ecological pillars could be defined as subsystems of a global open inductive sustainability system which considers feedbacks as evolution sources. An applicative illustration of this model will then be presented, through a case study describing 2012’s American severe drought event.
Modelling immune responses in sepsis
R Grealy, M White, M O'Dwyer, P Stordeur, DG Doherty, R McManus, T Ryan
Critical Care , 2012, DOI: 10.1186/cc10611
Abstract: A prospective observational study in a mixed medical/surgical ICU and general wards of a large academic teaching hospital was undertaken. Eighty ICU patients with a diagnosis of severe sepsis, 50 patients with mild sepsis (bacteraemia not requiring ICU admission) and 20 healthy controls were recruited. Gene expression analysis by qPCR for INFγ, TNFα, IL-2, IL-7, IL-10, IL-23, IL-27 on peripheral blood mononuclear cells (PBMCs) and serum protein analysis for IL-6 was performed. Multivariate analysis was used to construct a model of gene expression based on cytokine copy numbers alone and in combination with serum IL-6 levels.Sepsis was characterised by decreased IL-2, IL-7, IL-23, INFγ and greater TNFα, IL-10 and IL-27 gene expression levels compared to controls. Severe sepsis differed from mild sepsis by a decreased INFγ and increased IL-10 gene expression (P < 0.0001). A composite cytokine gene expression score differentiated controls from mild sepsis and mild sepsis from severe sepsis (P < 0.0001). A model combining these cytokine gene expression levels and serum IL-6 protein levels distinguished sepsis from severe sepsis with an ROC value of 0.89.Accurate modelling of patient response to infection is possible using peripheral blood mononuclear cell gene expression and serum protein analysis. Molecular biological techniques provide a robust method of such profiling. This approach may be used to evaluate novel sepsis therapies.
Pannexin 1 regulates postnatal neural stem and progenitor cell proliferation
Leigh E Wicki-Stordeur, Adrian D Dzugalo, Rose M Swansburg, Jocelyne M Suits, Leigh Swayne
Neural Development , 2012, DOI: 10.1186/1749-8104-7-11
Abstract: We detected pannexin 1 in neural stem and progenitor cells in vitro and in vivo. We manipulated pannexin 1 expression and activity in Neuro2a neuroblastoma cells and primary postnatal neurosphere cultures to demonstrate that pannexin 1 regulates neural stem and progenitor cell proliferation likely through the release of adenosine triphosphate (ATP).Permeable to ATP, a potent autocrine/paracine signaling metabolite, pannexin 1 channels are ideally suited to influence the behavior of neural stem and progenitor cells. Here we demonstrate they play a robust role in the regulation of neural stem and progenitor cell proliferation. Endogenous postnatal neural stem and progenitor cells are crucial for normal brain health, and their numbers decline with age. Furthermore, these special cells are highly responsive to neurological injury and disease, and are gaining attention as putative targets for brain repair. Therefore, understanding the fundamental role of pannexin 1 channels in neural stem and progenitor cells is of critical importance for brain health and disease.The majority of neurons are born embryonically, however neurogenesis continues in the postnatal brain throughout life (reviewed in [1]). Postnatal neurogenesis is a complex, multi-step developmental process that includes cell behaviors such as proliferation, differentiation and migration, and involves several distinct cell types. These stem cell behaviors are guided, in part, by extracellular stimuli unique to their specialized microenvironments or ‘niches’: the subgranular zone (SGZ) of the dentate gyrus and the ventricular zone (VZ) of the lateral ventricles (Figure 1A).Postnatal NSCs in the VZ generate large numbers of olfactory bulb interneurons. The distinct neural stem and progenitor cell (NSC/NPC) types implicated in this neurogenic process are characterized by their morphology and differential expression of lineage markers (Figure 1A). Radial glia-like cells (known as type B cells in VZ) express the fila
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