Uniform impact on individual megakaryocytes is essential for efficient in vitro platelet production.

Different approaches are being developed to efficiently produce in vitro platelets from cultured megakaryocytes to meet the constant demand of platelet transfusion and serve for research purposes. Recent works have shown that turbulence and periodic stress can significantly enhance platelet yield. Here we have developed and characterized a platelet production device that takes in account these properties.

Biomechanical consequences of the intervertebral disc centre of rotation kinematics during lateral bending and axial rotation.

The location of the instantaneous centre of rotation (ICR) of a lumbar unit has a considerable clinical importance as a spinal health estimator. Consequently, many studies have been conducted to measure or estimate the ICR during rotations in the three anatomical planes; however the results reported are widely scattered. Even if some inter-subjects variability is to be expected, such inconsistencies are likely explained by the differences in methods and experiments.

Assessment of intervertebral disc degeneration-related properties using finite element models based on [Formula: see text]-weighted MRI data.

Quantitative magnetic resonance imaging (MRI) provides useful information about intervertebral disc (IVD) biomechanical properties, especially those in relation to the fluid phase. These properties may improve IVD finite element (FE) models using data closer to physiological reality. The aim of this study is to investigate IVD degeneration-related properties using a coupling between MRI and FE modeling.

Morphological Analysis of Healthy Aortic Arch.

Objective/background: This study aimed to describe an arch morphology protocol in a healthy population, and to assess the impact of age and sex.

Methods: A retrospective morphology evaluation was conducted in a population with no personal history of thoracic aorta surgery or pathology, through computed tomography (CT) imaging analysis, using a standardised protocol. Based on centreline three dimensional coordinates, a single investigator calculated a series of parameters in the arch zones and in the total arch, using Matlab scripts.

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.

Risk Factor Analysis for the Mal-Positioning of Thoracic Aortic Stent Grafts.

Objective: The present study aimed at quantifying mal-positioning during thoracic endovascular aortic repair and analysing the extent to which anatomical factors influence the exact stent graft positioning.

Methods: A retrospective review was conducted of patients treated between 2007 and 2014 with a stent graft for whom proximal landing zones (LZ) could be precisely located by anatomical fixed landmarks, that is LZ 1, 2, or 3. The study included 66 patients (54 men; mean age 51 years, range 17-83 years) treated for traumatic aortic rupture (n = 27), type B aortic dissection (n = 21), thoracic aortic aneurysm (n = 8), penetrating aortic ulcer (n = 5), intramural hematoma (n = 1), and floating aortic thrombus (n = 4).

Quantitative MRI water content mapping of porcine intervertebral disc during uniaxial compression.

Background: Intervertebral disc (IVD) diseases are major public health problem in industrialized countries where they affect a large proportion of the population. In particular, IVD degeneration is considered to be one of the leading causes of pain consultation and sick leave. The aim of this study was to develop a new method for assessing the functionality of IVD in order to diagnose IVD degeneration.

Realistic glottal motion and airflow rate during human breathing.

The glottal geometry is a key factor in the aerosol delivery efficiency for treatment of lung diseases. However, while glottal vibrations were extensively studied during human phonation, the realistic glottal motion during breathing is poorly understood. Therefore, most current studies assume an idealized steady glottis in the context of respiratory dynamics, and thus neglect the flow unsteadiness related to this motion.

Risk Factor Analysis of Bird Beak Occurrence after Thoracic Endovascular Aortic Repair.

Objectives: The aim was to analyze the role played by anatomy and stent graft in the incidence of incomplete apposition to aortic arch.

Methods: Between 2007 and 2014 data including available and suitable computed tomographic angiography (CTA) imaging of patients who had undergone thoracic endovascular aortic repair were reviewed. The study included 80 patients (65 men, 54 ± 21 years) treated for traumatic aortic rupture (n = 27), thoracic aortic aneurysm (n = 15), type B aortic dissection (n = 24), penetrating aortic ulcer (n = 5), intramural hematoma (n = 2), aorto-oesophageal fistula (n = 2), and aortic mural thrombus (n = 5).

New experimental protocols for tensile testing of abdominal aortic analogues.

This work proposes an in vitro tensile testing protocol that is able to characterize abdominal aortic (AA) analogues under physiologically inspired mechanical loadings. Kinematic parameters are defined in agreement with in vivo measurements of aortic dynamics. A specific focus is given to the choice of the applied loading rates, deriving from the knowledge of aortic Peterson modulus and blood pressure variations from diastolic to systolic instants.

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.

Nutrient distribution and metabolism in the intervertebral disc in the unloaded state: a parametric study.

A 2-D finite element model for the intervertebral disc in which quadriphasic theory is coupled to the transport of solutes involved in cellular nutrition was developed for investigating the main factors contributing to disc degeneration. Degeneration is generally considered to result from chronic disc cell nutrition insufficiency, which prevents the cells from renewing the extracellular matrix and thus leads to the loss of proteoglycans. Hence, the osmotic power of the disc is decreased, causing osmomechanical impairments.

Numerical simulations of unsteady flows in a stenosed coronary bypass graft.

Using the finite element method, physiological blood flows through a three-dimensional model of a coronary graft are numerically analysed. The model includes a stenosis shape in the host artery upstream from the anastomosis. Recirculating areas, secondary flows, wall shear stress (WSS) and spatial wall shear stress gradients (WSSGs) are studied for different flow repartitions and at different times in the cycle.

Ethylene glycol ethers as hemopoietic toxins--in vitro studies of acute exposure.

Ethylene glycol ethers and their acetate derivatives were analyzed for their toxicity in vitro on several hemopoietic cell lines, either growth-factor-dependent or leukemic, in mouse, rat, and human species. Considering the concentrations that reduced the cell viability in culture by 50%, most of the ethylene glycol ethers and in particular ethylene glycol monoethyl ether (EGEE) or ethylene glycol monobutyl ether (EGBE) should be considered as hemopoietic toxins. EGBE was found to be the most potent toxin on the human promyelocytic cell line, NB4 (median inhibitory concentration (IC50) 5 mM at 6 h; IC50 0.

Glycol alkyl ethers as hemopoietic toxins.

Since 1971, glycol alkyl ethers have taken progressively the place of aromatic solvents including benzene. Experimental data point out to a possible toxicity on bone marrow, responsible of hypoplasia and even acute leukemia.