Search results for "TOXICITY"
showing 10 items of 2261 documents
Role of cAMP in mediating AHR signaling.
2009
Regulation of the nuclear import of many transcription factors represents a step in gene regulation which is crucial for a number of cellular processes. The aryl hydrocarbon receptor (AHR), a basic helix-loop-helix protein of the PAS (PER-ARNT-SIM) family of transcriptional regulators is a cytosol-associated and ligand-activated receptor. The environmental toxin dioxin binds with high affinity to AHR rendering it nuclear and leading to the activation of AHR sensitive genes. However, the fact, that the AHR mediates a large variety of physiological events without the involvement of any known exogenous ligand, including liver and vascular system development, maturation of the immune system, re…
Hot air stream reduces cytotoxicity of light-cured calcium hydroxide based cements
2019
Background The light-cured calcium hydroxide based cements have incomplete polymerization and unconverted monomers can cause pulp cell damage. The aim of this study was to evaluate the influence of a warm and hot air stream on the cytotoxicity of light-cured calcium hydroxide based cements. Material and methods The materials Dycal (conventional cement), Biocal, Hidrox-Cal, and Ultra-Blend Plus (light-cured calcium hydroxide cements) were submitted to cytotoxicity analysis after polymerization, without vs. with previous heat treatment with a warm (37°C) and a hot (60°C) air stream. Following polymerization, cements were maintained in culture medium for 24 hours and 7 days, and subjected to t…
Essential oil of Citrus lumia Risso: Phytochemical profile, antioxidant properties and activity on the central nervous system
2018
Citrus lumia Risso Essential oil Antioxidant properties Anti-cholinesterase activity Cytotoxicity Neuroactive effects 1. Introduction Plants that produce essential oils (EOs) represent a large part of natural flora and an important resource in various fields such as pharmaceutical, food and cosmetic industries, due to their flavor, fra- grance and biological activity (Swamy et al., 2016). EOs play a pivotal role in the growth and colonization of plants, giving color and scent to reproductive organs, attracting pollinators, favoring seed dispersion (Sharifi-Rad et al., 2017), and defending the plant against abiotic (light, temperature, etc.) and biotics (herbivores, harmful insects and pa- t…
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…
Possible Pathomechanisms Responsible for Injury to the Central Nervous System in the Settings of Chronic Cerebrospinal Venous Insufficiency
2012
The discovery of stenoses in the azygous and internal jugular veins, the so-called chronic cerebrospinal venous insufficiency that accompanies multiple sclerosis, has enabled the reinterpretation of knowledge about this neurologic dis- ease. Pathologic venous outflow from the central nervous system appears to lead to two main problems. Firstly, it disas- sembles the blood-brain barrier and may allow the penetration of nervous parenchyma by glutamate and leukocytes. Sec- ondly, it may result in significant hypoperfusion of the brain and spinal cord. These two overlapping pathologies are likely to trigger plaques through caspase-1-driven pyroptosis of oligodendrocytes and to evoke neurodegene…
Glutamate Excitotoxicity in the Cerebellum Mediated by IL-1β
2013
Multiple sclerosis (MS) is the prototypic inflammatory demyelinating disorder of the CNS. Symptoms of cerebellar dysfunction, such as tremors and ataxia, are relatively common in MS, but available treatment options are generally of limited value. Although many clinical manifestations of MS are
New polyamine drugs as more effective antichagas agents than benznidazole in both the acute and chronic phases.
2018
Abstract Despite the continuous research effort that has been made in recent years to find ways to treat the potentially life threatening Chagas disease (CD), this remains the third most important infectious disease in Latin America. CD is an important public health problem affecting 6–7 million people. Since the need to search for new drugs for the treatment of DC persists, in this article we present a panel of new polyamines based on the tripodal structure of tris(2-aminomethyl)amine (tren) that can be prepared at low cost with high yields. Moreover, these polyamines present the characteristic of being water-soluble and resistant to the acidic pH values of stomach, which would allow their…
Cytotoxicity of two naturally occurring flavonoids (dorsmanin F and poinsettifolin B) towards multi-factorial drug-resistant cancer cells.
2015
Abstract Introduction The expression of diverse resistance mechanisms in cancer cells is one of the major barriers to successful cancer chemotherapy. Methods In the present study, we assessed the cytotoxicity of two naturally occurring flavonoids dorsmanin F ( 1 , a flavanone) and poinsettifolin B ( 2 , a chalcone) against 9 drug-sensitive and multidrug-resistant (MDR) cancer cell lines. The resazurin reduction assay was used to evaluate the cytotoxicity of these compounds, whilst caspase-Glo assay was used to detect caspase activation. Cell cycle, mitochondrial membrane potential (MMP) and levels of reactive oxygen species (ROS) were all analysed via flow cytometry. Results Compounds 1 and…
Cytotoxicity and modes of action of 4'-hydroxy-2',6'-dimethoxychalcone and other flavonoids toward drug-sensitive and multidrug-resistant cancer cell…
2014
Abstract Introduction Resistance of cancer to chemotherapy is a main cause in treatment failure. Naturally occurring chalcones possess a wide range of biological activities including anti-cancer effects. In this work, we evaluated the antiproliferative activity of three chalcones [4′-hydroxy-2′,6′-dimethoxychalcone ( 1 ), cardamomin ( 2 ), 2′,4′-dihydroxy-3′,6′-dimethoxychalcone ( 3 )], and four flavanones [( S )-(–)-pinostrobin ( 4 ), ( S )-(–)-onysilin ( 5 ) and alpinetin ( 6 )] toward nine cancer cell lines amongst which were multidrug resistant (MDR) types. Methods The resazurin reduction assay was used to detect the antiproliferative activity of the studied samples whilst flow cytometr…
Cytotoxicity of three naturally occurring flavonoid derived compounds (artocarpesin, cycloartocarpesin and isobavachalcone) towards multi-factorial d…
2015
Abstract Introduction Cancer remains an aggressive deadly disease, if drug resistance develops. This problem is aggravated by the fact that multiple rather than single mechanisms are involved in resistance and that multidrug resistance (MDR) phenomena cause inefficacy of many clinical established anticancer drugs. We are seeking for novel cytotoxic phytochemicals to combat drug-resistant tumour cells. Methods In the present study, we investigated the cytotoxicity of three naturally occurring flavonoids including two flavones artocarpesin (1) and cycloartocarpesin (2) and one chalcone, isobavachalcone (3) against 9 drug-sensitive and MDR cancer cell lines. The resazurin reduction assay was u…