Search results for "TOXICITY"
showing 10 items of 2261 documents
Das chemotaktische Verhalten von Alveolarmakrophagen und Blutmonozyten nach Expositionen mit unterschiedlichen NO2-Konzentrationen
2008
The chemotaxis of alveolar macrophages (AM) and blood monocytes (BM) is important in the elimination of particles and microorganisms which have invaded the lung. The effect of nitrogen dioxide (NO2) on chemotaxis was tested on AM obtained by diagnostic bronchoscopy from five patients suspected of having bronchial carcinoma (four men, one woman; mean age 59 +/- 10 years). Blood monocytes were also studied with blood from seven healthy subjects (five men, two women; mean age 32 +/- 10 years). These cells were placed on polycarbonate membranes for 15 min each, exposed to NO2 concentrations between 1.0 and 5.0 parts per million (ppm), and then incubated with complement component C5a as chemotac…
Cytoprotective effects of carotenoids-rich extract from Lycium barbarum L. on the beauvericin-induced cytotoxicity on Caco-2 cells.
2019
Abstract In this work, the cytotoxicity of Beauvericin (BEA), lutein (LUT), zeaxanthin (ZEAX) and goji berries extract (GBE) rich in carotenoids, was investigated, as well as cytoprotective effects of these carotenoids against BEA induced-cytotoxicity on Caco-2 cells. Cytotoxicity was carried out using MTT and protein content (PC) assays during 24 and 48 h of exposure. Only BEA showed cytotoxic effect obtaining a reduction in cell proliferation range from 6.5 to 92.8%. Simultaneous combination of LUT and ZEAX with BEA slightly increased cell proliferation compared to BEA tested alone. LUT, ZEAX and GBE showed cytoprotective effects against cytotoxicity induced by BEA on Caco-2 cells. Pre-tr…
New amide and dioxopiperazine derivatives from leaves of Breynia nivosa
2017
The first chemical investigation of leaves of Breynia nivosa from Nigeria resulted in the isolation of two new amide derivatives breynivosamides A and B (1 and 2) and two new dioxopiperazine derivatives breynivosines A and B (4 and 5) together with seven known compounds (3, 6-11). The structures of the new compounds were elucidated by 1D, 2D NMR and HRESIMS data as well as by comparison with the literature. All isolated compounds were tested for the cytotoxic and antimicrobial activities. Only cristatin A (6) showed cytotoxicity against the L5178Y mouse lymphoma cell line with an IC50 value of 13.9μM while breynivosamide A (1) exhibited moderate antimicrobial activity against Mycobacterium …
An immune escape screen reveals Cdc42 as regulator of cancer susceptibility to lymphocyte-mediated tumor suppression.
2007
Abstract Adoptive cellular immunotherapy inducing a graft-versus-tumor (GVT) effect is the therapeutic mainstay of allogeneic hematopoietic stem cell transplantation (ASCT) for high-risk leukemias. Autologous immunotherapies using vaccines or adoptive transfer of ex vivo–manipulated lymphocytes are clinically explored in patients with various cancer entities. Main reason for failure of ASCT and cancer immunotherapy is progression of the underlying malignancy, which is more prevalent in patients with advanced disease. Elucidating the molecular mechanisms contributing to immune escape will help to develop strategies for the improvement of immunologic cancer treatment. To this end, we have und…
Manganese overload affects p38 MAPK phosphorylation and metalloproteinase activity during sea urchin embryonic development.
2014
Abstract In the marine environment, manganese represents a potential emerging contaminant, resulting from an increased production of manganese-containing compounds. In earlier reports we found that the exposure of Paracentrotus lividus sea urchin embryos to manganese produced phenotypes with no skeleton. In addition, manganese interfered with calcium uptake, perturbed extracellular signal-regulated kinase (ERK) signaling, affected the expression of skeletogenic genes, and caused an increase of the hsc70 and hsc60 protein levels. Here, we extended our studies focusing on the temporal activation of the p38 mitogen-activated protein kinase (p38 MAPK) and the proteolytic activity of metalloprot…
Recent advances in 2D and 3D in vitro systems using primary hepatocytes, alternative hepatocyte sources and non-parenchymal liver cells and their use…
2013
This review encompasses the most important advances in liver functions and hepatotoxicity and analyzes which mechanisms can be studied in vitro. In a complex architecture of nested, zonated lobules, the liver consists of approximately 80 % hepatocytes and 20 % non-parenchymal cells, the latter being involved in a secondary phase that may dramatically aggravate the initial damage. Hepatotoxicity, as well as hepatic metabolism, is controlled by a set of nuclear receptors (including PXR, CAR, HNF-4α, FXR, LXR, SHP, VDR and PPAR) and signaling pathways. When isolating liver cells, some pathways are activated, e.g., the RAS/MEK/ERK pathway, whereas others are silenced (e.g. HNF-4α), resulting in…
Sterigmatocystin-induced DNA damage triggers cell-cycle arrest via MAPK in human neuroblastoma cells
2021
Sterigmatocystin (STE) is a common mycotoxin found in food and feed. Many studies showed that STE is genotoxic. However, up to now, the potential genotoxicity of STE on human neuronal system remains unknown. In this study, we explored the effect of STE on DNA damage and cell-cycle progression on human neuroblastoma SH-SY5Y cells exposed to various concentrations of STE (0.78, 1.56 and 3.12 µM) for 24 h. The results indicated that STE exposure induced DNA damage, as evidenced by DNA comet tails formation and increased γH2AX foci. Additionally, genotoxicity was confirmed by micronuclei (MN) analysis. Furthermore, we found that STE exposure led to cell-cycle arrest at the S and the G2/M phase.…
Supraphysiological doses of performance enhancing anabolic-androgenic steroids exert direct toxic effects on neuron-like cells.
2013
Anabolic-androgenic steroids (AAS) are lipophilic hormones often taken in excessive quantities by athletes and bodybuilders to enhance performance and increase muscle mass. AAS exert well known toxic effects on specific cell and tissue types and organ systems. The attention that androgen abuse has received lately should be used as an opportunity to educate both athletes and the general population regarding their adverse effects. Among numerous commercially available steroid hormones, very few have been specifically tested for direct neurotoxicity. We evaluated the effects of supraphysiological doses of methandienone and 17-α-methyltestosterone on sympathetic-like neuron cells. Vitality and …
Effects of Scrophularia ningpoensis Hemsl. on Inhibition of Proliferation, Apoptosis Induction and NF-κB Signaling of Immortalized and Cancer Cell Li…
2012
Scrophularia ningpoensis has been used in China for centuries as a herbal tea to treat various diseases. Based on the numerous animal studies on its pharmaceutical effects and the long time clinical experiences, we studied the molecular and cellular mechanism underlying the bioactivity of aqueous extract of Scrophularia and its isolated compounds. Seven isolated compounds, unlike Scrophularia extract, failed to induce cytotoxicity on HaCaT cells, but their combination improved the effect of extract. Tumor cell line selectivity was not observed, when we studied its cytotoxic effect on melanoma cell lines. The apoptotic and anti-inflammatory effects of Scrophularia extract have been demonstra…
CD4+CD25+ regulatory T cells inhibit natural killer cell functions in a transforming growth factor-beta-dependent manner.
2007
Tumor growth promotes the expansion of CD4+CD25+ regulatory T (T reg) cells that counteract T cell–mediated immune responses. An inverse correlation between natural killer (NK) cell activation and T reg cell expansion in tumor-bearing patients, shown here, prompted us to address the role of T reg cells in controlling innate antitumor immunity. Our experiments indicate that human T reg cells expressed membrane-bound transforming growth factor (TGF)–β, which directly inhibited NK cell effector functions and down-regulated NKG2D receptors on the NK cell surface. Adoptive transfer of wild-type T reg cells but not TGF-β−/− T reg cells into nude mice suppressed NK cell–mediated cytotoxicity, redu…