Circulating cell membrane microparticles transfer heme to endothelial cells and trigger vasoocclusions in sickle cell disease.

Intravascular hemolysis describes the relocalization of heme and hemoglobin (Hb) from erythrocytes to plasma. We investigated the concept that erythrocyte membrane microparticles (MPs) concentrate cell-free heme in human hemolytic diseases, and that heme-laden MPs have a physiopathological impact. Up to one-third of cell-free heme in plasma from 47 patients with sickle cell disease (SCD) was sequestered in circulating MPs. Erythrocyte vesiculation in vitro produced MPs loaded with heme. In silico analysis predicted that externalized phosphatidylserine (PS) in MPs may associate with and help retain heme at the cell surface. Immunohistology identified Hb-laden MPs adherent to capillary endothelium in kidney biopsies from hyperalbuminuric SCD patients. In addition, heme-laden erythrocyte MPs adhered and transferred heme to cultured endothelial cells, inducing oxidative stress and apoptosis. In transgenic SAD mice, infusion of heme-laden MPs triggered rapid vasoocclusions in kidneys and compromised microvascular dilation ex vivo. These vascular effects were largely blocked by heme-scavenging hemopexin and by the PS antagonist annexin-a5, in vitro and in vivo. Adversely remodeled MPs carrying heme may thus be a source of oxidant stress for the endothelium, linking hemolysis to vascular injury. This pathway might provide new targets for the therapeutic preservation of vascular function in SCD.

Agents endowed with uncertainty management behaviors to solve a multiskill healthcare task scheduling.

Health organizations are complex to manage due to their dynamic processes and distributed hospital organization. It is therefore necessary for healthcare institutions to focus on this issue to deal with patients' requirements. We aim in this paper to develop and implement a management decision support system (DSS) that can help physicians to better manage their organization and anticipate the feature of overcrowding. Our objective is to optimize the Pediatric Emergency Department (PED) functioning characterized by stochastic arrivals of patients leading to its services overload. Human resources allocation presents additional complexity related to their different levels of skills and uncertain availability dates. So, we propose a new approach for multi-healthcare task scheduling based on a dynamic multi-agent system. Decisions about assignment and scheduling are the result of a cooperation and negotiation between agents with different behaviors. We therefore define the actors involved in the agents' coalition to manage uncertainties related to the scheduling problem and we detail their behaviors. Agents have the same goal, which is to enhance care quality and minimize long waiting times while respecting degrees of emergency. Different visits to the PED services and regular meetings with the medical staff allowed us to model the PED architecture and identify the characteristics and different roles of the healthcare providers and the diverse aspects of the PED activities. Our approach is integrated in a DSS for the management of the Regional University Hospital Center (RUHC) of Lille (France). Our survey is included in the French National Research Agency (ANR) project HOST (Hôpital: Optimisation, Simulation et évitement des Tensions (ANR-11-TecSan-010: http://host.ec-lille.fr/wp-content/themes/twentyeleven/docsANR/R0/HOST-WP0.pdf)).

Mapping patient path in the Pediatric Emergency Department: A workflow model driven approach.

The workflow models of the patient journey in a Pediatric Emergency Department (PED) seems to be an effective approach to develop an accurate and complete representation of the PED processes. This model can drive the collection of comprehensive quantitative and qualitative service delivery and patient treatment data as an evidence base for the PED service planning. Our objective in this study is to identify crowded situation indicators and bottlenecks that contribute to over-crowding. The greatest source of delay in patient flow is the waiting time from the health care request, and especially the bed request to exit from the PED for hospital admission. It represented 70% of the time that these patients occupied in the PED waiting rooms. The use of real data to construct the workflow model of the patient path is effective in identifying sources of delay in patient flow, and aspects of the PED activity that could be improved. The development of this model was based on accurate visits made in the PED of the Regional University Hospital Center (CHRU) of Lille (France). This modeling, which has to represent most faithfully possible the reality of the PED of CHRU of Lille, is necessary. It must be detailed enough to produce an analysis allowing to identify the dysfunctions of the PED and also to propose and to estimate prevention indicators of crowded situations. Our survey is integrated into the French National Research Agency (ANR) project, titled: "Hospital: Optimization, Simulation and avoidance of strain" (HOST).

Association of circulating endothelial microparticles with cardiometabolic risk factors in the Framingham Heart Study.

OBJECTIVE: To examine the relation of endothelial microparticles (EMPs) with cardiometabolic risk in the community. BACKGROUND: Circulating EMPs are small membrane vesicles released after endothelial cell injury. Endothelial microparticles are reportedly increased among individuals with a high burden of cardiovascular risk factors. However, prior investigations have been limited to small, highly selected samples. METHODS: We studied 844 individuals without a history of cardiovascular disease in the Framingham Offspring cohort (mean age 66 ± 9 years, 57% women). We used standardized flow cytometry methods to identify and quantify circulating CD144+ and CD31+/CD41- EMPs. We then used multivariable regression analyses to investigate the relations of EMP phenotypes with cardiovascular and metabolic risk factors. RESULTS: In multivariable analyses, the following cardiovascular risk factors were associated with one or more of the circulating EMP populations: hypertension (P = 0.025 for CD144+,), elevated triglycerides (P = 0.002 for CD144+, P < 0.0001 for CD31+/CD41-), and metabolic syndrome (P < 0.0001 for CD144+,). Overall, each tertile increase in the Framingham risk score corresponded to a 9% increase in log-CD31+/CD41- EMPs (P = 0.022). Furthermore, the presence of hypertriglyceridaemic waist status was associated with 38% higher levels of CD144+ EMPs (P < 0.0001) and 46% higher levels of CD31+/CD41- EMPs (P < 0.0001). CONCLUSION: In a large community-based sample, circulating EMP levels were associated with the presence of cardiometabolic risk factors, particularly dyslipidaemia. These data underscore the potential influence of high-risk metabolic profiles on endothelial integrity.

Erythrocyte microparticles can induce kidney vaso-occlusions in a murine model of sickle cell disease.

Patients with sickle cell disease suffer from painful crises associated with disseminated vaso-occlusions, increased circulating erythrocyte microparticles (MPs), and thrombospondin-1 (TSP1). MPs are submicron membrane vesicles shed by compromised or activated cells. We hypothesized that TSP1 mediates MP shedding and participates in vaso-occlusions. We injected TSP1 to transgenic SAD mice with sickle cell disease and characterized circulating phosphatidylserine+ MPs by FACS. TSP1 stimulated MPs in plasma and initiated vaso-occlusions within minutes. In vitro, TSP1 triggered rapid erythrocyte conversion into spicule-covered echinocytes, followed by MP shedding. MP shedding was recapitulated by peptides derived from the TSP1 carboxyterminus. We purified MPs shed by erythrocytes in vitro and administered them back to SAD mice. MPs triggered immediate renal vaso-occlusions. In vitro, MPs triggered the production of radical oxygen species by endothelial monolayers, favored erythrocyte adhesion, and induced endothelial apoptosis. MPs also compromised vasodilation in perfused microvessels. These effects were inhibited by saturating MP phosphatidylserine with annexin-V, or with inhibitors of endothelial ROS production. We conclude that TSP1 triggers erythrocyte MP shedding. These MPs induce endothelial injury and facilitate acute vaso-occlusive events in transgenic SAD mice. This work supports a novel concept that toxic erythrocyte MPs may connect sickle cell anemia to vascular disease.

Abnormal plasma microparticles impair vasoconstrictor responses in patients with cirrhosis.

BACKGROUND & AIMS: Circulating membrane-shed microparticles (MPs) participate in regulation of vascular tone. We investigated the cellular origins of MPs in plasma from patients with cirrhosis and assessed the contribution of MPs to arterial vasodilation, a mechanism that contributes to portal hypertension. METHODS: We analyzed MPs from blood samples of 91 patients with cirrhosis and 30 healthy individuals (controls) using flow cytometry; their effects on the vascular response to vasoconstrictors were examined in vitro and in vivo. RESULTS: Circulating levels of leuko-endothelial (CD31(+)/41(-)), pan-leukocyte (CD11a(+)), lymphocyte (CD4(+)), and erythrocyte (CD235a(+)) MPs were higher in patients with cirrhosis than in controls. Plasma of patients with cirrhosis contained hepatocyte-derived MPs (cytokeratin-18(+)), whereas plasma from controls did not. The severity of cirrhosis and systemic inflammation were major determinants of the levels of leuko-endothelial and hepatocyte MPs. MPs from patients with advanced cirrhosis significantly impaired contraction of vessels in response to phenylephrine, whereas MPs from healthy controls or from patients of Child-Pugh class A did not. This effect depended on cyclooxygenase type 1 and required phosphatidylserine on the surface of MPs. Intravenous injection of MPs from patients with cirrhosis into BALB/C mice decreased mean arterial blood pressure. CONCLUSIONS: Cirrhosis is associated with increases in circulating subpopulations of MPs, likely resulting from systemic inflammation and liver cell damage. The overall pool of circulating MPs from patients with advanced cirrhosis impairs vasoconstrictor responses and decreases blood pressure, contributing to the arterial vasodilation associated with portal hypertension.

Impact of the Automation of Inpatient Bed Management to Reduce the Emergency Service Waiting Time.

The patient waiting time to be transferred for hospitalization is the time that the patient waits between the decision to hospitalize and the actual admission to an inpatient hospital bed. One of the difficulties encountered in qualifying waiting time for inpatient bed is the inability of hospital information systems to measure it. Hospitals in France have a specialized bed allocation team. This team must manage the bed allocation problem between different hospital departments using phone communication to assign patients to the adapted service. This kind of communication represents a lengthy additional workload in which effectiveness is uncertain. This paper presents a new approach to automate bed management in downstream service. For that, we have implemented algorithms based on artificial intelligent integrated in an inpatient web platform using IoT-Beacons, which is implemented to improve and facilitate the exchange of availability information of downstream beds within the Lille university hospital center (LUHC).

Ontology for Overcrowding Management in Emergency Department.

Emergency department (ED) overcrowding is an ongoing problem worldwide. Scoring systems are available for the detection of this problem. This study aims to combine a model that allows the detection and management of overcrowding. Therefore, it is crucial to implement a system that can reason model, rank ED resources and ED performance indicators based on environmental factors. Thus, we propose in this paper a new domain ontology (EDOMO) based on a new overcrowding estimation score (OES) to detect critical situations, specify the level of overcrowding and propose solutions to deal with these situations. Our approach is based on a real database created during more than four years from the Lille University Hospital Center (LUHC) in France. The resulting ontology is capable of modeling complete domain knowledge to enable semantic reasoning based on SWRL rules. The evaluation results show that the EDOMO is complete that can enhance the functioning of the ED.

Augmented notebooks for pervasive learning in medical practice.

Medical e-learning can benefit from the new technologies, and pervasive learning resources and tools worth to be introduced in the medical context. Micro-learning seems to be an interesting way for pervasive learning. But it is still difficult to propose pedagogical resources that are built by learners, from meaningful experiments. We conducted an analysis of the exchanges performed by Health care professionals in the hospital in order to understand where and when educational exchanges appear. We analyzed the type of documents exchanged. The residents' paper notebooks caught our attention first because it answers some clinician-needs and second because the computerization of such a notebook could add a collaborative dimension to the pedagogical resources. We propose a model of an augmented resident's notebook and we briefly describe an implementation using Content Management System and WIKI, before setting the discussion and the conclusion sections.

An open repositories network development for medical teaching resources.

The lack of interoperability between repositories of heterogeneous and geographically widespread data is an obstacle to the diffusion, sharing and reutilization of those data. We present the development of an open repositories network taking into account both the syntactic and semantic interoperability of the different repositories and based on international standards in this field. The network is used by the medical community in France for the diffusion and sharing of digital teaching resources. The syntactic interoperability of the repositories is managed using the OAI-PMH protocol for the exchange of metadata describing the resources. Semantic interoperability is based, on one hand, on the LOM standard for the description of resources and on MESH for the indexing of the latter and, on the other hand, on semantic interoperability management designed to optimize compliance with standards and the quality of the metadata.

Hemostatic effects of recombinant DisBa-01, a disintegrin from Bothrops alternatus.

A monomeric RGD-disintegrin was recently identified from a cDNA library from the venom gland of Bothrops alternatus. The corresponding 12 kDa-recombinant protein, DisBa-01, specifically interacted with alpha(v)beta3 integrin and displayed potent anti-metastatic and anti-angiogenic properties. Here, the interaction of DisBa-01 with platelet alphaIIb beta3 integrin and its effects on hemostasis and thrombosis were investigated. DisBa-01 bound to Chinese Hamster Ovary (CHO) cells expressing beta3 or alphaIIb beta3 and promoted their adhesion and the adhesion of resting platelets onto glass coverslips. The disintegrin inhibited the binding of FITC-fibrinogen and FITC-PAC-1 to ADP-stimulated platelets and inhibited ADP-, TRAP- and collagen-induced aggregation of murine, rabbit or human platelets. In a flow chamber assay, DisBa-01 inhibited and reverted platelet adhesion to immobilized fibrinogen. DisBa-01 inhibited the phosphorylation of FAK following platelet activation. The intravenous injection of DisBa-01 in C57Bl6/j mice, prolonged tail bleeding time as well as thrombotic occlusion time in mesenteric venules and arterioles following vessel injury with FeCl3. In conclusion, DisBa-01 antagonizes the platelet alphaIIb beta3 integrin and potently inhibits thrombosis.

Endothelial Microparticles are Associated to Pathogenesis of Idiopathic Pulmonary Fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a devastating disease characterized by obliteration of alveolar architecture, resulting in declining lung function and ultimately death. Pathogenic mechanisms remain unclear but involve a concomitant accumulation of scar tissue together with myofibroblasts activation. Microparticles (MPs) have been investigated in several human lung diseases as possible pathogenic elements, prognosis markers and therapeutic targets. We postulated that levels and cellular origins of circulating MPs might serve as biomarkers in IPF patients and/or as active players of fibrogenesis. Flow cytometry analysis showed a higher level of Annexin-V positive endothelial and platelet MPs in 41 IPF patients compared to 22 healthy volunteers. Moreover, in IPF patients with a low diffusing capacity of the lung for carbon monoxide (DLCO<40%), endothelial MPs (EMPs) were found significantly higher compared to those with DLCO>40% (p = 0.02). We then used EMPs isolated from endothelial progenitor cells (ECFCs) extracted from IPF patients or controls to modulate normal human lung fibroblast (NHLF) properties. We showed that EMPs did not modify proliferation, collagen deposition and myofibroblast transdifferentiation. However, EMPs from IPF patients stimulated migration capacity of NHLF. We hypothesized that this effect could result from EMPs fibrinolytic properties and found indeed higher plasminogen activation potential in total circulating MPs and ECFCs derived MPs issued from IPF patients compared to those isolated from healthy controls MPs. Our study showed that IPF is associated with an increased level of EMPs in the most severe patients, highlighting an active process of endothelial activation in the latter. Endothelial microparticles might contribute to the lung fibroblast invasion mediated, at least in part, by a fibrinolytic activity.

An Internet supported workflow for the publication process in UMVF (French Virtual Medical University).

The " Université Médicale Virtuelle Francophone" (UMVF) is a federation of French medical schools. Its main goal is to share the production and use of pedagogic medical resources generated by academic medical teachers. We developed an Open-Source application based upon a workflow system, which provides an improved publication process for the UMVF. For teachers, the tool permits easy and efficient upload of new educational resources. For web masters it provides a mechanism to easily locate and validate the resources. For librarian it provide a way to improve the efficiency of indexation. For all, the utility provides a workflow system to control the publication process. On the students side, the application improves the value of the UMVF repository by facilitating the publication of new resources and by providing an easy way to find a detailed description of a resource and to check any resource from the UMVF to ascertain its quality and integrity, even if the resource is an old deprecated version. The server tier of the application is used to implement the main workflow functionalities and is deployed on certified UMVF servers using the PHP language, an LDAP directory and an SQL database. The client tier of the application provides both the workflow and the search and check functionalities. A unique signature for each resource, was needed to provide security functionality and is implemented using a Digest algorithm. The testing performed by Rennes and Lille verified the functionality and conformity with our specifications.

E-learning for students in their first year: a French experimentation at the medical school of Grenoble.

A local study carried out in the Medical School of Grenoble shows that teaching in the first year in medicine studies satisfies neither the students, nor the teachers. The Faculty of Medicine of Grenoble decided to set up a reform in order to offer a high quality education. This reform leads to a complete reorganization of the curriculum and to the intensive use of new information and communication technologies of information, in particular, the use of multimedia documents. The communication and information technologies team of the Faculty of Medicine of Grenoble carried out an innovating and daring reform to start at the academic year 2006-2007. The new course is built on three activities: self learning on multi-media resources, meetings with teachers for questions-answers sessions and tutorials animated by older students. This article reports the first results for this successful project. In the academic year 2006-2007, are concerned 1290 students, 40 teachers and 8 disciplines.

An Innovative Approach to Jointly Scheduling and Assigning a Consultation Time to Patients Arriving in the Emergency Department.

Emergency departments (ED) are facing problems related to the growing demand of care. Patients' management is carried out according to the type of patient and care required: already scheduled patients and non-scheduled urgent and non-urgent patients arriving in the ED. One of the main problems confronted in hospitals is the permanent interference between these different types of patients to be treated under the stochastic behaviors of consultation time and arrival flows, which prevents any prior planning. The present work proposes a dynamic scheduling method, considering the impact of new patients' arrivals on the treatment of patients already scheduled to minimize the mean waiting time of patients in the ED. The originality of this work is to assign, at the time of arrival, a scheduled time to each patient in order to reduce their stress. The performance of the proposed method is examined through a concrete application in the Pediatric Emergency Department of CHRU of Lille.

A MEDLINE categorization algorithm.

BACKGROUND: Categorization is designed to enhance resource description by organizing content description so as to enable the reader to grasp quickly and easily what are the main topics discussed in it. The objective of this work is to propose a categorization algorithm to classify a set of scientific articles indexed with the MeSH thesaurus, and in particular those of the MEDLINE bibliographic database. In a large bibliographic database such as MEDLINE, finding materials of particular interest to a specialty group, or relevant to a particular audience, can be difficult. The categorization refines the retrieval of indexed material. In the CISMeF terminology, metaterms can be considered as super-concepts. They were primarily conceived to improve recall in the CISMeF quality-controlled health gateway. METHODS: The MEDLINE categorization algorithm (MCA) is based on semantic links existing between MeSH terms and metaterms on the one hand and between MeSH subheadings and metaterms on the other hand. These links are used to automatically infer a list of metaterms from any MeSH term/subheading indexing. Medical librarians manually select the semantic links. RESULTS: The MEDLINE categorization algorithm lists the medical specialties relevant to a MEDLINE file by decreasing order of their importance. The MEDLINE categorization algorithm is available on a Web site. It can run on any MEDLINE file in a batch mode. As an example, the top 3 medical specialties for the set of 60 articles published in BioMed Central Medical Informatics & Decision Making, which are currently indexed in MEDLINE are: information science, organization and administration and medical informatics. CONCLUSION: We have presented a MEDLINE categorization algorithm in order to classify the medical specialties addressed in any MEDLINE file in the form of a ranked list of relevant specialties. The categorization method introduced in this paper is based on the manual indexing of resources with MeSH (terms/subheadings) pairs by NLM indexers. This algorithm may be used as a new bibliometric tool.

Recombinant tissue plasminogen activator enhances microparticle release from mouse brain-derived endothelial cells through plasmin.

Thrombolysis with recombinant tissue plasminogen activator (rt-PA) is currently the only approved pharmacological strategy for acute ischemic stroke. However, rt-PA exhibits vascular toxicity mainly due to endothelial damage. To investigate the mechanisms underlying rt-PA-induced endothelial alterations, we assessed the role of rt-PA in the generation of endothelial microparticles (EMPs), emerging biological markers and effectors of endothelial dysfunction. The mouse brain-derived endothelial cell line bEnd.3 was used. Cells were treated with rt-PA at 20, 40 or 80µg/ml for 15 or 24h, and EMPs were quantified in the culture media using Annexin-V staining coupled with flow cytometry. Rt-PA enhanced EMP release from bEnd.3 cells with a maximal increase at the 40µg/ml dose for 24h (+78% compared to controls). Using tranexamic acid and aprotinin we demonstrated that plasmin is responsible for rt-PA-induced EMP release. The p38 MAPK inhibitor SB203580 and the poly(ADP-ribose)polymerase (PARP) inhibitor PJ34 also reduced rt-PA-induced EMP production, suggesting that p38 MAPK and PARP are downstream intracellular effectors of rt-PA/plasmin. Rt-PA also altered through plasmin the morphology and the confluence of bEnd.3 cells. By contrast, these changes did not implicate p38 MAPK and PARP. This study demonstrates that rt-PA induces the production of microparticles by cerebral endothelial cells, through plasmin, p38 MAPK and PARP pathways. Determining the phenotype of these EMPs to clarify their role on the endothelium in ischemic conditions could thus be of particular interest.

Comparative evaluation of two applications for delivering a multimedia medical course in the French-speaking Virtual Medical University (UMVF).

This paper describes a comparative evaluation of two applications delivering a multimedia course: a conventional web server (WS) and an integrated e-learning platform in the form of a virtual campus (VC). We used a qualitative method for comparing their acceptance of the on-line course provided by the two different interfaces. The two groups were globally satisfied. However, a decrease in satisfaction was noted at the end of the experimentation in the VC group. This may be explained by a more complex graphic user interface of the VC and some constraints which do not exist with the WS. Students from both groups also had limitations about the multimedia environment.

Health Care Decision Support System for the Pediatric Emeregency Department Management.

Health organization management is facing a high amount of complexity due to the inherent dynamics of the processes and the distributed organization of hospitals. It is therefore necessary for health care institutions to focus on this issue in order to deal with patients' requirements and satisfy their needs. The main objective of this study is to develop and implement a Decision Support System which can help physicians to better manage their organization, to anticipate the overcrowding feature, and to establish avoidance proposals for it. This work is a part of HOST project (Hospital: Optimization, Simulation, and Crowding Avoidance) of the French National Research Agency (ANR). It aims to optimize the functioning of the Pediatric Emergency Department characterized by stochastic arrivals of patients which leads to its overcrowding and services overload. Our study is a set of tools to smooth out patient flows, enhance care quality and minimize long waiting times and costs due to resources allocation. So we defined a decision aided tool based on Multi-agent Systems where actors negotiate and cooperate under some constraints in a dynamic environment. These entities which can be either physical agents representing real actors in the health care institution or software agents allowing the implementation of optimizing tools, cooperate to satisfy the demands of patients while respecting emergency degrees. This paper is concerned with agents' negotiation. It proposes a new approach for multi-skill tasks scheduling based on interactions between agents.