1,721,009 research outputs found
Study of the crosstalk between hepatocytes and endothelial cells using a novel multicompartmental bioreactor: a comparison between connected cultures and cocultures
No full textThe liver and other organs are connected to each other through the bloodstream. Therefore, the connection between tissues is generally mediated by soluble molecules able to cross the endothelial wall of capillaries. We developed a multicompartmental device, multicompartmental bioreactor (MCB), designed to mimic the connection between different tissues in which crosstalk is mediated by soluble molecules transported through the blood. A comparative study of the crosstalk between hepatocytes (HepG2) and endothelial cells (human umbilical vein endothelial cells) in connected culture in the MCB and in a traditional static coculture system was performed by analyzing glucose consumption and secretion of albumin, urea, and nitric oxide. When hepatocytes and endothelial cells were cultured together, the production of albumin and urea increased, and the increase was higher in the MCB than in traditional static coculture. In spite of this enhanced metabolic activity, the crosstalk between hepatocytes and endothelial cell leads to decreased glucose consumption with respect to hepatocytes alone, both in static and in dynamic conditions. However, the dynamic connected culture has a higher rate of metabolite synthesis and secretion with respect to cocultures. This means a more efficient use of energetic substrates and enhanced hepatocyte function in the MCB
Protocol to generate an in vitro model to study vascular calcification using human endothelial and smooth muscle cells
Full text linkVascular calcification is a systemic disease characterized by calcium salt deposition
within vascular walls. Here, we present a protocol for establishing an
advanced dynamic in vitro co-culture system using endothelial and smooth muscle
cells to replicate vascular tissue complexity. We describe steps for cell culture
and seeding in a double-flow bioreactor that recreates the action of blood in humans.
We then detail the induction of calcification, setting up of the bioreactor,
followed by cell viability assessment and calcium quantification
Connected Culture of Murine Hepatocytes and HUVEC in a Multicompartmental Bioreactor
No full textA multicompartmental bioreactor was conceived and designed to mimic cross talk between cells in different culture chambers connected only by flow, such that cell-cell interaction is mediated by soluble ligands as occurs in the body. The system was tested with a connected culture of murine hepatocytes and human umbilical vein endothelial cells. Metabolites such as albumin, urea, lactate and viability were monitored during the course of the experiments and compared with monoculture conditions in the bioreactor. When the two cell types are placed in connected culture, there is an increase in endothelial cell viability and hepatic glucose synthesis as well as albumin and urea production, while overall lactate production in the system is downregulated. The results show that the multicompartmental bioreactor enhances cell function, effectively combining both heterotypic interactions with increased nutrient availability
A microfluidic gradient maker for toxicity testing of bupivacaine and lidocaine
No full textA great deal of effort is being dedicated to the development of new devices able to conduct effective in vitro toxicology analyses, This paper describes the use of a microfluidic gradient maker for the toxicological analysis of two conventional local anesthetics, bupivacaine and lidocaine on cell cultures The. microfluidic device was designed and simulated using COMSOL Multiphysics (R) and the concentration gradient in the microfluidic network was analysed through a fluidodynamic and diffusive Study
PAM2 (Piston Assisted Microsyringe): A New Rapid Prototyping Technique for Biofabrication of Cell Incorporated Scaffolds
No full textRapid prototyping techniques are widely used to fabricate well-defined three-dimensional structures of tissue homologs. The piston-assisted microsyringe (PAM2) is a rapid prototyping technology specifically developed for low-shear stress extrusion of viscous hydrogel solutions containing cells. In this article the working parameters of the system were established to guarantee the realization of spatially controlled hydrogel scaffolds. Moreover the shear stresses acting on the cell membrane during extrusion was investigated through a computational fluid-dynamic analysis. The computational models show that the shear stress on the cells is of the order of 100 Pa during the extrusion process. HepG2 cells encapsulated in alginate were then extruded into spatially organized hepatic lobule-like architectures and their viability and function were evaluated. The results show that the metabolic fingerprint of the cells is preserved with respect to controls and the cells are uniformly distributed through the gel scaffold
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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