Side-dependent effect in the response of valve endothelial cells to bidirectional shear stress.

Endothelial cells covering the aortic and ventricular sides of the aortic valve leaflets are exposed to different stresses, in particular wall shear stress (WSS). Biomechanical stimuli actively regulate valve tissue structure and induce remodeling events leading to valve dysfunction. Endothelial to mesenchymal transformation (EndMT), for example, has been associated with aortic valve disease.

Biaxial tensile tests of the porcine ascending aorta.

One of the aims of this work is to develop an original custom built biaxial set-up to assess mechanical behavior of soft tissues. Stretch controlled biaxial tensile tests are performed and stereoscopic digital image correlation (SDIC) is implemented to measure the 3D components of the generated displacements. Using this experimental device, the main goal is to investigate the mechanical behavior of porcine ascending aorta in the more general context of human ascending aorta pathologies.

Flow of a blood analogue fluid in a compliant abdominal aortic aneurysm model: experimental modelling.

The aim of this work is to develop a unique in vitro set-up in order to analyse the influence of the shear thinning fluid-properties on the flow dynamics within the bulge of an abdominal aortic aneurysm (AAA). From an experimental point of view, the goals are to elaborate an analogue shear thinning fluid mimicking the macroscopic blood behaviour, to characterise its rheology at low shear rates and to propose an experimental device able to manage such an analogue fluid without altering its feature while reproducing physiological flow rate and pressure, through compliant AAA. Once these experimental prerequisites achieved, the results obtained in the present work show that the flow dynamics is highly dependent on the fluid rheology.

Risk management of excreta in a cancer unit.

Although many legal and clinical requirements are in effect for the preparation and administration of the antineoplasic drugs, limited data exist on the potential cytotoxic risk to healthcare personnel from exposure of excreta (urine, feces, expectorations, saliva, perspiration, and vomiting) from patients. A preliminary risk analysis was conducted with a multidisciplinary work group. The objectives were to identify all potential hazards and accidental events that may lead to an accident related to the excreta management and to implement a global risk reduction and quality improvement policy.

[Assessment of nursing needs and risk management in geriatric oncology].

In France, the incidence and rate of mortality of cancer increase with age. For elderly patients suffering from cancer, the standard geriatric assessment, together with an oncological assessment aims to optimise the treatment. This geriatric oncology assessment enables the priorities to be identified and the cancer treatment to be adapted by anticipating the risks and organising the support care.

[Controlling risks in healthcare institutions].

The management of a healthcare institution generates risks through the very hazards of the management process. The management of these risks is integrated into the global safety management process and into the strategic thinking of geriatric hospitals.

[Implementation of a procedure for nominating a health care surrogate].

A procedure for the systematic nomination of a health care surrogate was put in place following a multi-disciplinary approach within an acute care geriatric unit at Ambroise-Paré hospital in Boulogne-Billancourt. Its originality lies in the way the whole team, on the initiative of a doctor, prepared the procedure, implemented it and assessed it. A review.

New insights into the understanding of flow dynamics in an in vitro model for abdominal aortic aneurysms.

An in vitro dynamics set-up of the flow in a compliant abdominal aortic aneurysm (AAA) model with an anterior posterior asymmetry, aorto-iliac bifurcation, and physiological inlet flow rate and outlet pressure waveforms was developed. The aims were first to show that the structural mechanical behavior of the used material to mimic the AAA wall was similar to this of patients with AAA and then to study the influence of the aorto-iliac bifurcation presence and to study the influence of the imbalanced flow rate in the iliac branches on the AAA flow field. 3D visualizations, never performed in the literature, have clearly put into evidence the development of a vortex ring generated at the AAA proximal neck during the decelerating phase of flow rate, which detaches and progresses downstream during the cardiac cycle, impinges on the anterior wall in the distal AAA region, breaks up, and separates into two vortices of which one rolls on upstream along the anterior wall.

Stereoscopically observed deformations of a compliant abdominal aortic aneurysm model.

A new experimental setup has been implemented to precisely measure the deformations of an entire model abdominal aortic aneurysm (AAA). This setup addresses a gap between the computational and experimental models of AAA that have aimed at improving the limited understanding of aneurysm development and rupture. The experimental validation of the deformations from computational approaches has been limited by a lack of consideration of the large and varied deformations that AAAs undergo in response to physiologic flow and pressure.

Two-dimensional intraventricular flow mapping by digital processing conventional color-Doppler echocardiography images.

Doppler echocardiography remains the most extended clinical modality for the evaluation of left ventricular (LV) function. Current Doppler ultrasound methods, however, are limited to the representation of a single flow velocity component. We thus developed a novel technique to construct 2D time-resolved (2D+t) LV velocity fields from conventional transthoracic clinical acquisitions.

[Mapping hazardous situations with regard to fall risk].

The mapping of hazardous situations aims to provide a practical representation of the ranking of vulnerabilities in patient care. While there is no universally recognised method, a task force working on fall risk at Ambroise Paré hospital in Boulogne (AP-HP, Hauts-de-Seine) has drawn up a map charting the a posteriori and a priori identification and analysis of risks. Mobilising the professionals involved is essential in order to achieve as comprehensive a map as possible.

Numerical and experimental study of blood flow through a patient-specific arteriovenous fistula used for hemodialysis.

Arteriovenous fistula (AVF) pathologies related to blood flow necessitate valid calculation tools for local velocity and wall shear stress determination to overcome the clinical diagnostic limits. To illustrate this issue, a reconstructed patient-specific AVF was investigated, using computational fluid dynamics (CFDs) and particle image velocimetry (PIV). The aim of this study was to validate the methodology from medical images to numerical simulations of an AVF by comparing numerical and experimental data.

Antibody-based proteomics: analysis of signaling networks using reverse protein arrays.

Protein kinases drive the cellular signal transduction networks that underlie the regulation of growth, survival and differentiation. To repair the deregulations of signaling cascades that are associated with numerous disease states, therapeutic strategies, based on controlling aberrant protein kinase activity, are emerging. To develop such therapies it is crucial to have knowledge of the full complexity of signaling networks at a molecular level in order to understand the information flow through signaling cascades and their cell and tissue specificity.

Validation of a numerical 3-D fluid-structure interaction model for a prosthetic valve based on experimental PIV measurements.

A numerical 3-D fluid-structure interaction (FSI) model of a prosthetic aortic valve was developed, based on a commercial computational fluid dynamics (CFD) software program using an Arbitrary Eulerian Lagrangian (ALE) formulation. To make sure of the validity of this numerical model, an equivalent experimental model accounting for both the geometrical features and the hydrodynamic conditions was also developed. The leaflet and the flow behaviours around the bileaflet valve were investigated numerically and experimentally by performing particle image velocimetry (PIV) measurements.

Analysis of blood flow behaviour in custom stent grafts.

Endovascular aneurysm repair (EVAR) is an attractive alternative to open surgery for treating abdominal aortic aneurysms (AAAs). However, the implantation of stent grafts into AAAs can result in post-operative complications such as stent graft migration, rupture or endoleak. EVAR has therefore been carried out only on selected patients.

Biophotonics applied to proteomics.

Since the completion of the human genome sequencing, our understanding of gene and protein function and their involvement in physiopathological states has increased dramatically, partly due to technological developments in photonics. Photonics is a very active area where new developments occur on a weekly basis, while established tools are adapted to fulfill the needs of other disciplines like genomics and proteomics. Biophotonics emerged at the interface of photonics and biology as a very straightforward and efficient approach to observe and manipulate living systems.

[Misoprostol for treating postpartum hemorrhages].

Postpartum hemorrhage is defined by bleeding > 500 mL through the vagina. It is one of the obstetrical complications that obstetricians fear most. It is the leading cause of maternal mortality in the world, especially in developing countries.

Flow behaviour in an asymmetric compliant experimental model for abdominal aortic aneurysm.

An experimental study was carried out on asymmetrical abdominal aortic aneurysm (AAA) to analyse the physiological flows involved. Velocity measurements were performed using particle image velocimetry. Resting and exercise flow rates were investigated in models with rigid and compliant walls to assess the parameters affecting the flow behaviour.

Identification of apolipoprotein A-I as a "STOP" signal for myopia.

Good visual acuity requires that the axial length of the ocular globe is matched to the refractive power of the cornea and lens to focus the images of distant objects onto the retina. During the growth of the juvenile eye, this is achieved through the emmetropization process that adjusts the ocular axial length to compensate for the refractive changes that occur in the anterior segment. A failure of the emmetropization process can result in either excessive or insufficient axial growth, leading to myopia or hyperopia, respectively.

In vitro atrial flow dynamics: normal conditions versus atrial fibrillation.

Aims: The flow dynamics in the atrium is poorly described. The reasons are principally due to the complicated geometry of the cavity and its contractility. The present in vitro study focuses on the description of the flow in the left atrium in normal conditions (NC) and in atrial fibrillation (AF).