Search results for "Acellular"
showing 10 items of 1986 documents
The unsolved relationship of brain aging and late-onset Alzheimer disease.
2009
Late-onset Alzheimer disease is the most common form of dementia and is strongly associated with age. Today, around 24 million people suffer from dementia and with aging of industrial populations this number will significantly increase throughout the next decades. An effective therapy that successfully decelerates or prevents the progressive neurodegeneration does not exist. Histopathologically Alzheimer disease is characterized by extensive extracellular amyloid beta (Abeta) plaques, intracellular neurofibrillary tangles (NFTs), synaptic loss and neuronal cell death in distinct brain regions. The molecular correlation of Abeta or NFTs and development of late-onset Alzheimer disease needs f…
Regulation of tumour cell sensitivity to TNF-induced oxidative stress and cytotoxicity: Role of glutathione
1998
Glutathione (GSH) and the rate of cellular proliferation determine tumour cell sensitivity to tumour necrosis factor (TNF). Buthionine sulphoximine (BSO), a selective inhibitor of GSH synthesis, inhibits tumour growth and increases recombinant human TNF (rhTNF)-alpha cytoxicity in vitro. Administration of sublethal doses of rhTNF-alpha to Ehrlich ascites-tumour (EAT)-bearing mice induces oxidative stress (as measured by increases in intracellular peroxide levels, O2.- generation and mitochondrial GSSG). ATP-induced selective GSH depletion, when combined with rhTNF-alpha administration, affords a 61% inhibition of tumour growth and results in a significant extent of host survival. Administra…
Anti-Proliferative Activity of A Hydrophilic Extract of Manna from Fraxinus angustifolia Vahl through Mitochondrial Pathway-Mediated Apoptosis and Ce…
2020
Manna is produced from the spontaneous solidification of the sap of some Fraxinus species, and, owing its content in mannitol, is used in medicine as a mild laxative. Manna is also a rich source of characteristic bio-phenols with reducing, antioxidant and anti-inflammatory properties. This study assesses the activity of a hydrophilic extract of manna (HME) on cellular and molecular events in human colon-rectal cancer cells. HME showed a time- and concentration-dependent anti-proliferative activity, measured by MTT assay, in all the cell lines examined, namely Caco-2, HCT-116 and HT-29. The amounts of HME that caused 50% of cell death after a 24 h treatment were 8.51 ±
Poriferan survivin exhibits a conserved regulatory role in the interconnected pathways of cell cycle and apoptosis
2010
Survivin orchestrates intracellular pathways during cell division and apoptosis. Its central function as mitotic regulator and inhibitor of cell death has major implications for tumor cell proliferation. Analyses in early-branching Metazoa so far propose an exclusive role of survivin as a chromosomal passenger protein, whereas only later during evolution a complementary antiapoptotic function might have arisen, concurrent with increased organismal complexity. To lift the veil on the ancestral function(s) of this key regulator, a survivin-like protein (SURVL) of one of the earliest-branching metazoan taxa was identified and functionally characterized. SURVL of the sponge Suberites domuncula …
Apoptosis in liver disease.
2006
The description of the morphological hallmarks of programmed cell death, apoptosis, in 1972 by Kerr, Wyllie and Currie started a field of research that revolutionized our understanding of cellular proliferation, tissue homeostasis and pathophysiology of many diseases. In the following years, a series of proteins involved in signaling and intracellular death pathways were identified and 30 years later the Noble Prize for physiology and medicine was awarded to S. Brenner, H. R. Horvitz and J. E. Sulston for their discoveries related to describing the mechanisms of cell death (apoptosis). The delineation of the signaling pathways that mediate apoptosis changed the paradigms of understanding in…
Characterization of cells with different mitochondrial membrane potential during apoptosis.
2005
Background Until now, the simultaneous analysis of several parameters during apoptosis, including DNA content and mitochondrial membrane potential (ΔΨ), has not been possible because of the spectral characteristics of the commonly used dyes. Using polychromatic flow cytometry based upon multiple laser and UV lamp excitation, we have characterized cells with different ΔΨ during apoptosis. Methods U937 cells were treated with the flavonoid quercetin (Qu) and stained with JC-1 to detect ΔΨ, propidium iodide (PI) for cell viability, Hoechst 33342 for DNA content, Annexin V conjugated with Alexa Fluor-647 for detection of phosphatidilserine (PS) exposure, marker of early apoptosis, or Mitotracke…
Lysosomal degradation of the carboxydextran shell of coated superparamagnetic iron oxide nanoparticles and the fate of professional phagocytes
2010
Contrast agents based on dextran-coated superparamagnetic iron oxide nanoparticles (SPIO) are internalized by professional phagocytes such as hepatic Kupffer cells, yet their role in phagocyte biology remains largely unknown. Here we investigated the effects of the SPIO ferucarbotran on murine Kupffer cells and human macrophages. Intravenous injection of ferucarbotran into mice led to rapid accumulation of the particles in phagocytes and to long-lasting increased iron deposition in liver and kidneys. Macrophages incorporate ferucarbotran in lysosomal vesicles containing α-glucosidase, which is capable of degrading the carboxydextran shell of the ferucarbotran particles. Intravenous injectio…
Absence of oxysterol-like side effects in human monocytic cells treated with phytosterols and oxyphytosterols
2012
Oxysterols, found in some commonly consumed foods, can induce a wide range of cytotoxic effects, which have been extensively studied. On the other hand, the side effects of phytosterols and oxyphytosterols are less well-known. Over the past few years, different types of foods have been enriched with phytosterols on the basis of the properties of these compounds that reduce circulating cholesterol levels in certain experimental conditions. It is therefore important to gain better knowledge of the risks and benefits of this type of diet. In this study, conducted in human monocytic U937 cells, the ability of phytosterols (sitosterol, campesterol) and oxyphytosterols (7 beta-hydroxysitosterol, …
Toxic effects on astrocytes of extracellular vesicles from CSF of multiple sclerosis patients: a pilot in vitro study.
2020
Multiple sclerosis (MS) is an autoimmune and degenerative disorder of the central nervous system (CNS) that causes a progressive loss of motor and cognitive perfor-mances. Moreover, since the earlier phases, axonal loss as well as neuronal degener-ation and a failure of oligodendrocytes to promote myelin repair have been demon-strated. In previous studies, it has been shown that the treatment of rat neuronal primary cultures with serum from MS patients can be toxic for neurons. Here we report a pilot investigation showing that CSF from patients contains extracellular vesicles (EVs) able to induce cell death in rat cultured astrocytes. Although these data are still preliminary, they suggest …
Autophagy-Dependent Anticancer Immune Responses Induced by Chemotherapeutic Agents in Mice
2011
Antineoplastic chemotherapies are particularly efficient when they elicit immunogenic cell death, thus provoking an anticancer immune response. Here we demonstrate that autophagy, which is often disabled in cancer, is dispensable for chemotherapy-induced cell death but required for its immunogenicity. In response to chemotherapy, autophagy-competent, but not autophagy-deficient, cancers attracted dendritic cells and T lymphocytes into the tumor bed. Suppression of autophagy inhibited the release of adenosine triphosphate (ATP) from dying tumor cells. Conversely, inhibition of extracellular ATP-degrading enzymes increased pericellular ATP in autophagy-deficient tumors, reestablished the recr…