Search results for "mechanical"
showing 10 items of 5999 documents
Mechanical ventilation alters the development of staphylococcus aureus pneumonia in rabbit
2016
Ventilator-associated pneumonia (VAP) is common during mechanical ventilation (MV). Beside obvious deleterious effects on muco-ciliary clearance, MV could adversely shift the host immune response towards a pro-inflammatory pattern through toll-like receptor (TLRs) up-regulation. We tested this hypothesis in a rabbit model of Staphylococcus aureus VAP. Pneumonia was caused by airway challenge with S. aureus, in either spontaneously breathing (SB) or MV rabbits (n = 13 and 17, respectively). Pneumonia assessment regarding pulmonary and systemic bacterial burden, as well as inflammatory response was done 8 and 24 hours after S. aureus challenge. In addition, ex vivo stimulations of whole blood…
Linezolid and atorvastatin impact on pneumonia caused by Staphyloccocus aureus in rabbits with or without mechanical ventilation
2017
International audience; Pneumonia may involve methicillin-resistant Staphylococcus aureus (MRSA), with elevated rates of antibiotics failure. The present study aimed to assess the effect of statins given prior to pneumonia development. Spontaneously breathing (SB) or mechanically ventilated (MV) rabbits with pneumonia received atorvastatin alone, linezolid (LNZ) alone, or a combination of both (n = 5 in each group). Spontaneously breathing and MV untreated infected animals (n = 11 in each group), as well as uninfected animals (n = 5 in each group) were used as controls. Microbiological features and inflammation were evaluated. Data are presented as medians (interquartile range). Linezolid a…
Heat- and pH-induced BSA conformational changes, hydrogel formation and application as 3D cell scaffold
2016
Aggregation and gelation of globular proteins can be an advantage to generate new forms of nanoscale biomaterials based on the fibrillar architecture. Here, we report results obtained by exploiting the proteins' natural tendency to self-organize in 3D network, for the production of new material based on BSA for medical application. In particular, at five different pH values the conformational and structural changes of the BSA during all the steps of the thermal aggregation and gelation have been analyzed by FTIR spectroscopy. The macroscopic mechanical properties of these hydrogels have been obtained by rheological measurements. The microscopic structure of the gels have been studied by AFM…
Large strain stimulation promotes extracellular matrix production and stiffness in an elastomeric scaffold model
2016
Mechanical conditioning of engineered tissue constructs is widely recognized as one of the most relevant methods to enhance tissue accretion and microstructure, leading to improved mechanical behaviors. The understanding of the underlying mechanisms remains rather limited, restricting the development of in silico models of these phenomena, and the translation of engineered tissues into clinical application. In the present study, we examined the role of large strip-biaxial strains (up to 50%) on ECM synthesis by vascular smooth muscle cells (VSMCs) micro-integrated into electrospun polyester urethane urea (PEUU) constructs over the course of 3 weeks. Experimental results indicated that VSMC …
Effect of intermittent shear stress on corneal epithelial cells using an in vitro flow culture model.
2018
Abstract Purpose The aim of this study was to establish and to evaluate an in vitro model for culturing human telomerase-immortalized corneal epithelial (hTCEpi) cells under adjustable medium flow mimicking the movements of the tear film on the ocular surface. Methods Using an IBIDI pump system, cells were cultured under unidirectional, continuous or oscillating, discontinuous medium flow. Cell surface and cytoskeletal architecture were investigated by scanning electron microscopy and immunofluorescence. Gene expression of e-cadherin, occludin, tight junction protein (TJP), desmoplakin, desmocollin and mucins was investigated by real-time PCR. Protein expression of desmoplakin, TJP, occludi…
Characterization of Hydrothermal Processing Influence on Strontium Substituted Apatite by Investigating Stable Oxygen Isotope Ratio and Antibacterial…
2018
Synthetic hydroxyapatite (HAp) has weak antibacterial and mechanical properties. The antibacterial activity of HAp can be enhanced by strontium cation substitution and incorporation of peroxide ion via hydrothermal processing at 100 °C and 150 °C temperature using 50% H2O2 solution. The starting reagents and products of HAp processing were analyzed by thermal conversion elemental analyser – isotopic ratio mass spectrometer in order to determine the δ18O values. Using different host materials it could be possible to determine differences of δ18O values between untreated and hydrothermally treated HAp samples. The enhanced antibacterial properties of processed HAp samples were investigated us…
Heat shock protein 70 dampens the inflammatory response of human PDL cells to mechanical loading in vitro
2019
BACKGROUND AND OBJECTIVE Previously, we demonstrated an inflammatory response of human PDL (hPDL) cells to mechanical loading. The cellular reaction was dampened by heat pre-treatment suggesting a protective role for heat shock proteins (HSP) during stress-induced ischemia. Here we explored if HSP70, which has already been documented in the pressure zone of tooth movement, might be regulatorily involved in the attenuation of the inflammatory response. MATERIALS AND METHODS Fifth passage hPDL cells were mechanically loaded in the presence of the HSP70 inhibitor VER155008. Cell morphology, HSP70 expression, viability, IL-6 and IL-8 expression were determined by means of microscopy, realtime-P…
Effect of Isothiocyanates on the Activity of <i>Lactobacillus plantarum</i> Exposed to Irradiation
2020
Two isothiocyanates, i.e., sulforaphane (SFA) and sulforaphene (SFE), are suggested to be used as an alternative chemopreventive diet. This study was focused on the effect of SFA and SFE on Lactobacillus plantarum, which has been subjected to the irradiation (2-50 Gy). The cultures grown in De Man, Rogosa and Sharpe (MRS) and Tryptone Soya Broth (TSB) were compared in terms of bacteria physiological activity under tested conditions. Broth composition notably influenced the bacteria growth kinetic parameters, as well as culture response to the oxidative stress. Activity of L. plantarum cells after irradiation was evaluated by their dehydrogenase (DHA) and quinone-reductase (QR) activities. T…
A Basic Architecture of an Autonomous Adaptive System With Conscious-Like Function for a Humanoid Robot.
2018
In developing a humanoid robot, there are two major objectives. One is developing a physical robot having body, hands, and feet resembling those of human beings and being able to similarly control them. The other is to develop a control system that works similarly to our brain, to feel, think, act, and learn like ours. In this article, an architecture of a control system with a brain-oriented logical structure for the second objective is proposed. The proposed system autonomously adapts to the environment and implements a clearly defined “consciousness” function, through which both habitual behavior and goal-directed behavior are realized. Consciousness is regarded as a function for effecti…
Carbonic anhydrase and metazoan biocalcification: a focus on molluscs.
2015
Carbonic anhydrase is a super-family of metallo-enzymes (containing α, β, γ, ζ and δ-CA families) that catalyse the reversible hydration of carbon dioxide. Among their numerous functions, CAs - in particular that of the α-CA family - are known to play a key role in biocalcification processes, i.e., the ability to deposit calcium carbonate crystallites in a controlled manner to form exoskeletons. In the gastropod mollusc Haliotistuberculata – the European abalone – we identified two CA transcripts, htCA1 and htCA2, in the mantle, the calcifying organ responsible for shell formation from an extracellular organic matrix and a mixture of inorganic ions. Because these two transcripts are specifi…