Search results for "VITRO"

In vitro fusion of phagosomes with different endocytic organelles from J774 macrophages.

1998

We describe novel biochemical and electron microscopy assays to investigate in vitro fusion of latex bead phagosomes with three different endocytic organelle fractions from J774 macrophages. After formation, early phagosomes fuse avidly with early and late endosomes and for a longer period of time with lysosomes, but they subsequently become fusion-incompetent. The fusion of early, but not late, phagosomes with all three endocytic fractions could be significantly stimulated by Rab5. In contrast to other cell types investigated, this Rab is uniquely enriched on both early and late endosomes in J774 macrophages. Moreover, exogenous Rab5 stimulates homotypic fusion between both sets of organel…

Increased adhesion and activation of polymorphonuclear neutrophil granulocytes to endothelial cells under heavy metal exposure in vitro.

1994

Heavy metals have been implicated in the mechanisms of endothelial damage. Influences of heavy metal ions on diverse cell types have been studied using a variety of in vitro and in vivo methods. Polymorphonuclear neutrophil granulocytes (PMNs) have physiological and pathological functions, including the modulation of adhesion to and destruction of endothelial cells (ECs). PMNs were studied during interaction with human umbilical vein ECs under exposure to zinc, nickel and cobalt using an in vitro model. We studied adhesion processes with the help of a computer-controlled image-analyzing system and examined the activation of PMNs by quantification of leukotriene B4 (LTB4) release. The biphas…

Evolution of RNA virus in spatially structured heterogeneous environments

2003

A hallmark of the infectious cycle for many RNA viruses parasitizing multicellular hosts is the need to invade and successfully replicate in tissues that comprise a variety of cell types. Thus, multicellular hosts represent a heterogeneous environment to evolving viral populations. To understand viral adaptation to multicellular hosts, we took a double approach. First, we developed a mathematical model that served to make predictions concerning the dynamics of viral populations evolving in heterogeneous environments. Second, the predictions were tested by evolving vesicular stomatitis virus in vitro on a spatially structured environment formed by three different cell types. In the absence o…

Human Endothelial and Osteoblast Co-cultures on 3D Biomaterials

2010

Increasingly, in vitro experiments are being used to evaluate the cell compatibility of novel biomaterials. Single cell cultures have been used to determine how well cells attach, grow, and exhibit characteristic functions on these materials and the outcome of such tests is generally accepted as an indicator of biocompatibility. However, organs and tissues are not made up of one cell type and the interaction of cells is known to be an essential factor for physiological cell function. To more accurately examine biomaterials for bone regeneration, we have developed methods to coculture osteoblasts, which are the primary cell type making up bone, and endothelial cells, which form the vasculatu…

Synthesis and in vitro Evaluation of (S)-2-([11C]Methoxy)-4- [3-methyl-1-(2-piperidine-1-yl-phenyl)-butyl-carbamoyl]-benzoic Acid ([11C]Methoxy-repag…

2005

Spontaneous lymphokine synthesis by human blood mononuclear cells

1975

LYMPHOCYTES, after antigenic stimulation, may synthesise and release biologically active soluble factors other than antibodies. These mediators were termed lymphokines by Dumonde1, and the most extensively studied and best characterised are migration inhibitory factors which can inhibit the migration of macrophages or leukocytes: this is the property used for their in vitro bioassay. Apart from antigens, various other stimuli may trigger lymphokine synthesis by lymphocytes, for example, polyclonal mitogens2, anti-immunoglobulin or membrane Fc or C3-receptor reactions3,4. Furthermore, migration inhibitory activity has been found in the long term culture supernatants of some established lymph…

Transport of resveratrol, a cancer chemopreventive agent, to cellular targets: plasmatic protein binding and cell uptake

2004

Resveratrol produced by several plants, berries and fruits, including grapes, is one of the best known natural food microcomponents with potent chemopreventive properties towards the most severe contemporary human diseases: cardiovascular sickness, cancer and neurodegenerative pathologies. Demonstration of its mechanism of action also implies the elucidation of the steps of bioavailability and bioabsorption in cells and tissues. In order to estimate the relationships between the amounts of resveratrol taken up by food or drink intake, and the several possible benefits illustrated from in vitro/in vivo experiments and from epidemiological studies, it is essential to demonstrate step by step …

Evidence for a common progenitor of epithelial and mesenchymal components of the liver

2013

Tissues of the adult organism maintain the homeostasis and respond to injury by means of progenitor/stem cell compartments capable to give rise to appropriate progeny. In organs composed by histotypes of different embryological origins (e.g. The liver), the tissue turnover may in theory involve different stem/precursor cells able to respond coordinately to physiological or pathological stimuli. In the liver, a progenitor cell compartment, giving rise to hepatocytes and cholangiocytes, can be activated by chronic injury inhibiting hepatocyte proliferation. The precursor compartment guaranteeing turnover of hepatic stellate cells (HSCs) (perisinusoidal cells implicated with the origin of the …

Temporal Monitoring of Differentiated Human Airway Epithelial Cells Using Microfluidics

2015

The airway epithelium is exposed to a variety of harmful agents during breathing and appropriate cellular responses are essential to maintain tissue homeostasis. Recent evidence has highlighted the contribution of epithelial barrier dysfunction in the development of many chronic respiratory diseases. Despite intense research efforts, the responses of the airway barrier to environmental agents are not fully understood, mainly due to lack of suitable in vitro models that recapitulate the complex in vivo situation accurately. Using an interdisciplinary approach, we describe a novel dynamic 3D in vitro model of the airway epithelium, incorporating fully differentiated primary human airway epith…

Improved synthesis and in vitro evaluation of the cytotoxic profile of oxysterols oxidized at C4 (4α- and 4β-hydroxycholesterol) and C7 (7-ketocholes…

2013

Whereas the biological activities of oxysterols oxidized at C7 (7-ketocholesterol (7KC), 7β-hydroxycholesterol (7β-OHC), 7α-hydroxycholesterol (7α-OHC)) are well documented, those of oxysterols oxidized at C4 (4β-hydroxycholesterol (4β-OHC), 4α-hydroxycholesterol (4α-OHC)) are not well known, especially on the cells of the central nervous system. Therefore, an improved methodology has been validated for 4β-OHC and 4α-OHC synthesis, and the effects on cell viability and cell growth of these molecules were studied on immortalized, tumoral and normal brain cells (158N, C6 and SK-N-BE cells, and mixed primary cultures of astrocytes and oligodendrocytes). Whereas inhibition of cell growth with 7…