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Cytotoxic Effects (cytotoxic + effects)
Selected AbstractsINDIVIDUAL AND COMBINED CYTOTOXIC EFFECTS OF THE MAJOR FOUR AFLATOXINS IN DIFFERENT IN VITRO STABILIZED SYSTEMSJOURNAL OF FOOD BIOCHEMISTRY, Issue 5 2010CORNELIA BRAICU ABSTRACT The present study aims to investigate the cytotoxic effect of the major aflatoxins (B1, B2, G2 and G2) and also aflatoxin combination, using a simple, rapid and cheap cytotoxicity test like MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay in three in vitro models (human umbilical vein endothelial cells [HUVEC], human lung fibroblasts [HFL] and A2780 cell line) and to extrapolate the data to in vivo situation using a prediction model. A difference in cell sensitivity has been observed for B1 and B1 + B2, in the following order A2789 > HFL > HUVEC, while for B2, G1, G2, Mix (B1 + B2 + G1 + G2) the order was HFL > A2789 > HUVEC when comparing the IC50 (half maximal inhibitory concentration) values. We confirm that in vitro cytotoxicity test MTT assay is able to predict in vivo toxicity, at least for aflatoxins using the prediction model. The values of LD50 (lethal dose 50%) calculated from experiments are different for each cell line. This fact may indicate that some species are more resistant than other and target organs are not necessarily those predicted, because the A2780 ovarian cancer cells seem to be more sensitive to B1 than cells of endothelial or fibroblasts origin. PRACTICAL APPLICATIONS This study is in concordance with the international tendency that refined the current techniques to lessen pain or distress, to reduce the number of animals necessary for a particular test or to replace animals with non-whole-animal models, such as in vitro cell cultures. The practical application of such methodologies may help solve the economic problem related to very expensive in vivo toxicology studies and implement preventive methods based on the calculated data and known mechanism of action of individual or combined toxins easily studied in vitro. The nature of coexistence of many types of mycotoxins in complex environmental samples, such as food and water, has been reported worldwide. How these mycotoxins might affect human health in combination is largely unknown. This study had, as a goal, to test the toxicity of the four aflatoxins and aflatoxin combination on human cells. Due to the lack of aflatoxins mixture data regarding the human cytotoxicity, the aim of this study was to specify, evaluate and predict the combined effects of mycotoxin mixtures. [source] Estrogen Receptor Expression and Estrogen Receptor-independent Cytotoxic Effects of Tamoxifen on Malignant Rhabdoid Tumor Cells in vitroCANCER SCIENCE, Issue 12 2002Shigeki Koshida Recent studies have shown that the antiestrogen tamoxifen (TAM) can be used in the treatment of malignant neoplasms other than breast cancer. In the present study, we investigated the expression of estrogen receptor (ER) in six malignant rhabdoid tumor (MRT) cell lines. Alterations in MRT cell growth in response to estrogen or antiestrogens (4-hydroxytamoxifen (4-OHT), TAM, and ICI 182 780) were also investigated. RT-PCR and western blotting showed that ER-a was expressed in three of the six MRT cell lines. While 17-,-estradiol (E2) did not significantly alter MRT cell line proliferation, the hydroxylated tamoxifen metabolite 4-OHT significantly inhibited the growth of all 6 MRT cell lines. However, the steroidal antiestrogen ICI 182 780 did not alter the proliferation of any of the MRT cell lines. 4-OHT induced apoptosis in both ER-,-negative and ER-,-positive MRT cell lines, as assessed by nuclear morphology and DNA fragmentation. Neither growth inhibition nor induction of apoptosis due to 4-OHT was blocked by the addition of excess E2. Our data suggested that 4-OHT induced cytotoxic effects against MRT cells, and that these effects were independent of ER expression. [source] Cytotoxic effects induced by hexachlorobenzene in Squilla mantis (L.) (Crustacea, Stomatopoda)ENVIRONMENTAL TOXICOLOGY, Issue 1 2008Antonio Dell'Anno Abstract Contamination of marine environments by hexachlorobenzene (HCB) represents a serious concern for potential consequences on ecosystem and human health. Despite this, information on cytotoxic effects on marine organisms is still largely lacking. In this study, we investigated cytotoxic effects induced by HCB on gonads and muscular tissue of Squilla mantis by analysing Na+/K+ -ATPase activity and plasma membrane fluidity. This crustacean species was selected as a model for its habitat, trophic level, feeding behavior, and commercial exploitation for human consumption. Time course experiments revealed that low concentrations of HCB (i.e. 50 nM) determine an exponentially decrease of Na+/K+ -ATPase activity and a significant modification of cellular membrane fluidity. Significant negative relationships between Na+/K+ -ATPase activity and membrane fluidity were observed, suggesting that changes in the structure and packing of cellular membranes induced by HCB may be the primary factor affecting the activity of essential bilayer-associated enzymes. Overall these findings suggest that even small concentrations of HCB may determine important changes on cell metabolism with potential cascade effects on recruitment of this commercial species. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008. [source] Subchronic organismal toxicity, cytotoxicity, genotoxicity, and feeding response of pacific oyster (Crassostrea gigas) to lindane (,-HCH) exposure under experimental conditionsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 10 2007Gerardo Anguiano Abstract This study evaluated organismal toxicity, cytotoxicity, and genotoxicity and the filtration rate in response to different concentrations of subchronic lindane (gamma-hexachlorocyclohexane [,-HCH]), exposure (12 d) in adult Pacific oysters Crassostrea gigas. Oysters were exposed in vivo in laboratory aquaria to 10 different concentrations (0.0,10.0 mg/L) of ,-HCH. The median lethal concentration (LC50) after 12 d was calculated as 2.22 mg/L. Cytotoxic effects were observed in hemocytes, where the mean cell viability was significantly decreased at 1.0 mg/L of ,-HCH after 12 d. Genotoxicity of ,-HCH measured by single cell gel electrophoresis assay, in hemocytes was evident at 0.7 mg/L of ,-HCH after 12 d. After 4 h of exposure to ,-HCH, filtration rates were reduced compared with controls to 65.8 and 38.2% at concentrations of 0.3 and 0.7 mg/L, respectively, and after 11 d of exposure, filtration rates were reduced to 60.4 and 30.9% at concentrations of 0.1 mg/L and higher. These results show the subchronic effects of ,-HCH at different concentrations and effect sensitivities are categorized as filtration rate < genotoxicity < cytotoxicity < mortality. The relevance of integral toxicity evaluation, considering different endpoints from molecular, cellular, and individual levels is discussed. [source] Examination of cytotoxicity and mutagenicity of AH26 and AH Plus sealersINTERNATIONAL ENDODONTIC JOURNAL, Issue 5 2003I. Mileti Abstract Aim ,To study in vitro the cytotoxic and mutagenic effects of AH26 and AH Plus. Methodology ,Cytotoxic effects on Chinese hamster V79 cells were determined by counting viable cells following incubation with eluations of AH26 and AH Plus. In one set of experiments, the materials were mixed, set for 1 h and then eluted with dimethyl sulphoxide (DMSO) for 1 h, 24 h and 7 days. In the other set, AH26 and AH Plus were mixed and set for 1 h, 24 h and 7 days in physiological saline then crushed and eluted in DMSO for 24 h. The cytotoxic effects of these eluates were evaluated. Three concentrations were chosen to examine the mutagenic effects of AH26 and AH Plus: 5.57, 16.7 and 55.7 ,g mL,1. The structural chromosomal aberration analysis and micronucleus test were performed on human lymphocytes according to standard procedures. Results ,Dose,response curves of cell survival were obtained. Both materials were shown to be cytotoxic in doses larger than 55.7 ,g mL,1, except for AH26, after 7 days setting time. AH Plus was also shown to be toxic in concentrations of 16.7 ,g mL,1, except after 7 days setting time. Neither AH26 nor AH Plus induced a significant increase of chromosomal aberrations or micronuclei induction at any setting time or concentration. Conclusion ,There was no mutagenicity found for AH26 and AH Plus on human lymphocytes in highly controlled conditions in vitro. [source] Cytotoxic effects of ,, T cells expanded ex vivo by a third generation bisphosphonate for cancer immunotherapyINTERNATIONAL JOURNAL OF CANCER, Issue 1 2005Kiyoshi Sato Abstract Nitrogen containing-bisphosphonates (N-BPs), widely used to treat bone diseases, have direct antitumor effects via the inactivation of Ras proteins. In addition to the direct antitumor activities, N-BPs expand gd,,T cells, which exhibit major histocompatibility complex-unrestricted lytic activity. BPs accumulate intermediate metabolites which may be tumor antigens in target cells. The purpose of our study was to clarify the cytotoxicity of gd,, T cells expanded ex vivo by the most potent N-BP, zoledronate (ZOL). Especially, we focused on the importance of pretreatment against target cells also with ZOL; 1 m,M ZOL plus IL-2 increased the absolute number of gd,,T cells 298,768 fold for 14 days incubation. The small cell lung cancer and fibrosarcoma cell lines pretreated with 5 m,M ZOL showed a marked increase in sensitivity to lysis by gd,,T cells. While, untreated cell lines were much less sensitive to lysis by gdT cells. Video microscopy clearly demonstrated that gd,,T cells killed target cells pre-treated with ZOL within 3 hr. Pretreatment with 80 m,g/kg ZOL also significantly enhanced the antitumor activity of gd,,T cells in mice xenografted with SBC-5 cells. These findings show that ZOL significantly stimulated the proliferation of gd,,T cells and that gd,,T cells required pre-treatment with ZOL for cytotoxic activity against target cells. © 2005 Wiley-Liss, Inc. [source] Cytotoxic effects of polychlorinated biphenyl hydroquinone metabolites in rat hepatocytesJOURNAL OF APPLIED TOXICOLOGY, Issue 2 2010Katie Chan Abstract Polychlorinated biphenyls (PCBs) are persistent organic pollutants that exhibit various toxic effects in animals and exposed human populations. The molecular mechanisms of PCB toxicity have been attributed to the toxicological properties of its metabolites, such as hydroquinones, formed by cytochrome-P-450 oxidation. The effects of PCB hydroquinone metabolites towards freshly isolated rat hepatocytes were investigated. Hydroquinones can be oxidized to semiquinones and/or quinone metabolites. These metabolites can conjugate glutathione or can oxidize glutathione as a result of redox cycling. This depletes hepatocyte glutathione, which can inhibit cellular defence mechanisms, causing cell death and an increased susceptibility to oxidative stress. However in the following, glutathione-depleted hepatocytes became more resistant to the hydroquinone metabolites of PCBs. This suggested that their glutathione conjugates were toxic and that there was a third type of quinone toxicity mechanism which involved a hydrogen peroxide-accelerated autoxidation of the hydroquinones to form toxic electrophilic quinone and semiquinone,glutathione conjugates. Copyright © 2009 John Wiley & Sons, Ltd. [source] Cytotoxic effects of dental resin liquids on primary gingival fibroblasts and periodontal ligament cells in vitroJOURNAL OF ORAL REHABILITATION, Issue 12 2004Y.-L. Lai summary, Cytotoxic effects of resin liquids of three in situ relining dental polymers, AlikeTM, Kooliner, and Tokuso Rebase, and their major components, methyl methacrylate (MMA), isobutyl methacrylate (IBMA), and 1,6-hexanediol dimethacrylate (1,6-HDMA) were investigated. The concentrations of major monomers in these resin liquids were determined by high-performance liquid chromatography. Cellular viability of human gingival fibroblasts (GF) and periodontal ligament (PDL) cells were evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyltetrazolium bromide assay. Moreover, patterns of cell death were analysed using annexin V/propidium iodide staining with flow cytometry. The results indicated that AlikeTM liquid contained 91·3% MMA, Kooliner liquid contained 94·5% IBMA, and Tokuso Rebase liquid contained 65·8% 1,6-HDMA. All materials examined had cytotoxic effects on GF and PDL cells in dose-dependent manners. Tokuso Rebase liquid appeared to be the most cytotoxic among the various resin liquids examined. The effects of Kooliner and Tokuso Rebase liquids may have resulted from IBMA and 1,6-HDMA, respectively. Furthermore, the majority of treated cells died from necrosis; whereas a small portion of cells died from apoptosis. In conclusion, the results demonstrated that these liquid forms of dental polymers and their major monomers cause cytotoxic reactions. The direct relining procedure that cures these materials in situ should be used cautiously. [source] Cytotoxic effects of gingival retraction cords on human gingival fibroblasts in vitroJOURNAL OF ORAL REHABILITATION, Issue 4 2004C.-M. Liu summary, The objective of this study was to determine the cytocompatibility of three different extracts of gingival retraction cords and to compare the cytotoxic effect of these materials on human gingival fibroblasts. Gingival retraction cords impregnated with aluminium sulphate (Gingi-Aid), dl -adrenaline HCl (Gingi-Pak) and non-drug-impregnated cord (Gingi-Plain) were eluted with culture medium for 10 min and 24 h. Cytotoxicity was judged using a tetrazolium bromide reduction assay. Our data demonstrated that gingival retraction cords applied alone almost completely inhibited cell viability (P < 0·05). In addition, the results also showed that the eluates from aluminium sulphate-impregnated cord, dl -adrenaline HCl-impregnated cord and non-drug-impregnated cord were cytotoxic to primary human gingival fibroblast cultures (P < 0·05). The cell viability of incubation of gingival fibroblasts containing 10-min eluates of aluminium sulphate, dl -adrenaline HCl and non-drug-impregnated cord was 61, 21 and 70%, respectively. The cell viability of incubation of gingival fibroblasts containing 24 h eluates of aluminium sulphate, dl -adrenaline HCl and non-drug-impregnated cord was 68, 58 and 72%, respectively. It was found that dl -adrenaline HCl-impregnated gingival retraction cord was the most toxic gingival retraction cord among the materials tested in all cultures (P < 0·05). The cytotoxicity decreased in an order of dl -adrenaline HCl-impregnated cord > aluminium sulphate-impregnated cord > non-drug-impregnated cord. The extent or degree of the cytotoxicity depended on the materials tested. Gingival retraction cords have significant potential for gingival toxicity. Careful management of gingiva retraction cords would lower the risk of potential gingival tissue damage during clinical application procedure and thus increase the success of prosthodontic procedures. [source] In vitro evaluation of bevacizumab toxicity on a retinal ganglion cell lineACTA OPHTHALMOLOGICA, Issue 6 2009Rajesh K. Sharma Abstract. Purpose:, The effects of bevacizumab on cell viability and proliferation in a commonly used retinal ganglion cell line, RGC-5, were examined. Methods:, RGC-5 cells were exposed to 0.1 mg/ml, 1 mg/ml and 2 mg/ml of commercially available bevacizumab in vitro. To examine the specificity of effects, cells were also cultured with increasing and comparable concentrations of proteins (increasing the concentration of proteins in the culture media by 0.1 mg/ml, 1 mg/ml and 2 mg/ml by using additional fetal bovine serum [FBS] and bovine serum albumin [BSA]). Cell proliferation was assessed using a WST-1 kit, crystal violet staining and bromodeoxyuridine (BrdU) incorporation. Cytotoxic effects were assessed by quantifying cell numbers in proliferation-deficient RGC-5 following exposure to bevacizumab using the WST-1 kit, microscopic examination of cells stained with propidium iodide (PI) cells and flow cytometry for differential staining with PI. Results:, Bevacizumab was not toxic to RGC-5 cells in the tested concentrations. It had a stimulatory effect on cell proliferation. A stimulatory effect on proliferation was also noted when equivalent amounts of proteins from FBS or BSA were used, which suggests that bevacizumab may stimulate proliferation non-specifically by increasing the protein contents of the cell growth environment. Conclusions:, Results suggest that intravitreal injection of bevacizumab could alter the internal milieu of the eye by increasing protein concentrations to elicit functional responses in retinotypic cells. This may be especially relevant for cells outwith the control of vascular endothelial growth factor. [source] Cytotoxic effects induced by hexachlorobenzene in Squilla mantis (L.) (Crustacea, Stomatopoda)ENVIRONMENTAL TOXICOLOGY, Issue 1 2008Antonio Dell'Anno Abstract Contamination of marine environments by hexachlorobenzene (HCB) represents a serious concern for potential consequences on ecosystem and human health. Despite this, information on cytotoxic effects on marine organisms is still largely lacking. In this study, we investigated cytotoxic effects induced by HCB on gonads and muscular tissue of Squilla mantis by analysing Na+/K+ -ATPase activity and plasma membrane fluidity. This crustacean species was selected as a model for its habitat, trophic level, feeding behavior, and commercial exploitation for human consumption. Time course experiments revealed that low concentrations of HCB (i.e. 50 nM) determine an exponentially decrease of Na+/K+ -ATPase activity and a significant modification of cellular membrane fluidity. Significant negative relationships between Na+/K+ -ATPase activity and membrane fluidity were observed, suggesting that changes in the structure and packing of cellular membranes induced by HCB may be the primary factor affecting the activity of essential bilayer-associated enzymes. Overall these findings suggest that even small concentrations of HCB may determine important changes on cell metabolism with potential cascade effects on recruitment of this commercial species. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008. [source] Cytotoxicity and oxidative stress caused by chemicals adsorbed on particulate matter,ENVIRONMENTAL TOXICOLOGY, Issue 5 2006Andrea Müller Abstract Air particulate matter (PM) and bound chemicals are potential mediators for adverse health effects. The cytotoxicity and changes in energy-providing processes caused by chemical compounds bound to PM of different size fractions were investigated in Tetrahymena pyriformis. The PM samplings were carried out using a high volume cascade impactor (6 size fractions between 10 ,m and less than 0.49 ,m) at three points of La Plata, Argentina: in an industrial area, a traffic-influenced urban area, and a control area. Extracts from respirable particles below 1 ,m initiated the highest cytotoxic effects, demonstrating their higher risk. In contrast, an increase on oxygen consumption was observed especially in tests of extracts from particles less than 1 ,m from urban and industrial areas. The increase on oxygen consumption could be caused by decoupling processes in the respiratory chain. Otherwise the ATP concentration was increased too, even though to a lower extent. The observed imbalance between oxygen consumption and ATP concentration in exposed T. pyriformis cells may be due to oxidative stress, caused by chemical compounds bound to the particles. Owing to the complexity of effects related to PM and their associated chemical compounds, various physiological parameters necessarily need to be investigated to obtain more information about their possible involvement in human relevant pathogenic processes. As shown here, effects on cell proliferation and on energy-providing processes are suitable indicators for the different impact of PM and adsorbed chemicals from various sampling locations. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 457,463, 2006. [source] Development of an in vitro blood,brain barrier model to study the effects of endosulfan on the permeability of tight junctions and a comparative study of the cytotoxic effects of endosulfan on rat and human glial and neuronal cell culturesENVIRONMENTAL TOXICOLOGY, Issue 3 2006Melissa P. L. Chan Abstract Endosulfan, an organochlorine (OC) insecticide that belongs to the cyclodiene group, is one of the most commonly used pesticides to control pests in vegetables, cotton, and fruits. Porcine brain microvascular endothelial cells were used to develop a model to study the effects of endosulfan on the permeability of tight junctions in the blood,brain barrier (BBB). BBB permeability, measured as transendothelial electrical resistance, decreased in a dose- and time-dependent manner when treated with ,-endosulfan, ,-endosulfan, or endosulfan sulfate. Cytotoxicity testing revealed that the three endosulfans did not cause cell death at concentrations of 10 ,M and below. The ratio of the average permeability of the filter-grown endothelial cell monolayer to 14C-endosulfan (Pe) going from the outer to the inner compartments with that going from the inner to the outer compartments was approximately 1:1.2,2.1 after exposure to concentrations of 0.01,10 ,M. ,-Endosulfan, ,-endosulfan, and endosulfan sulfate had cytotoxic effects on rat glial (C6) and neuronal (PC12) cell cultures as well as on human glial (CCF-STTG1) and neuronal (NT2) cell cultures. The effects of ,-endosulfan were highly selective, with a wide range of LC50 values found in the different cultures, ranging from 11.2 ,M for CCF-STTG1 cells to 48.0 ,M for PC12 cells. In contrast, selective neurotoxicity was not so manifest in glial and neuronal cell cultures after exposure to endosulfan sulfate, as LC50 values were in the range of 10.4,21.6 ,M. CCF-STTG1 cells were more sensitive to ,-endosulfan and endosulfan sulfate, whereas NT2 cells were more sensitive to ,-endosulfan. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 223,235, 2006. [source] Characteristics of okadaic acid,induced cytotoxic effects in CHO K1 cellsENVIRONMENTAL TOXICOLOGY, Issue 6 2003C. Huynh-Delerme Abstract This article reports the results of investigations into the process of cell death induced in the Chinese hamster ovary cell K1 subclone (CHO K1) by okadaic acid (OA), a hydrophobic polyether produced by marine dinoflagellates. The IC50 was about 13 nM OA after 24 h of treatment, as determined using neutral red. With the MTT assay, the IC50 was 25 nM, although in this case 25% of the initial staining was still observed at 100 nM. Hoechst staining showed that mitotic figures accumulated at 12 nM OA after a 24- or 48-h treatment. In experiments limited to a 3-day treatment without changing the medium, CHO K1 cells were engaged in the death process at 50 nM OA after about 20 h and at 10 nM OA after 48 h. In many cells nuclear fragmentation that resulted in the apparent appearance of vesicles correlated with increasing cellular volume. But additional cell fragmentation was not observed with any treatment, and the chromatin material seemed to progressively disappear inside the cells. DNA fragmentation was analyzed by electrophoresis and with the TUNEL technique. With both techniques, the DNA was fragmented by 48 h in both 25 and 50 nM OA. Electrophoresis showed that both adherent and nonadherent cells were affected. Annexin-positive/ propidium iodide (PI),negative cells were rarely observed after OA treatment. Some were seen under the scanning cytometer after 20 h at 50 nM OA or after 48 h at 10 nM OA, but they were never detected by flow cytometry. Most of the time scanning cytometry showed either unstained cells or PI-positive (annexin-positive or -negative) cells (48 h, 50 nM, or 72 h, 10 nM). Flow cytometry cytograms showed two cell subpopulations: one composed of a majority of smaller cells, the other of larger cells. The larger cells markedly decreased with time and OA treatment (50 and 100 nM). Stained-cell counting showed that all cells that stained were both annexin- and PI positive and that most PI-positive cells were smaller. Ki67 antigen labeling showed the proliferative activity of CHO K1 cultures but also demonstrated the loss of this activity in smaller cells treated with 50 nM OA for 48 h. We concluded that in our culture conditions the main OA target within CHO K1 cultures was dividing cells. Our results suggest that cells with disturbed metaphase,anaphase enter apoptosis, leading to necrotic daughter cells. © 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 383,394, 2003 [source] Cytotoxicity of settling particulate matter and sediments of the Neckar River (Germany) during a winter floodENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2000Henner Hollert Abstract To investigate the cytotoxic and genotoxic potentials of settling particulate matter (SPM) carried by the Neckar River, a well-studied model for a lock-regulated river in central Europe, during a flood, acute cytotoxicity was investigated using the fibroblast-like fish cell line RTG-2 with the neutral red retention, the succinic acid dehydrogenase (MTT), and the lactatedehydro-genase (LDH) release assays as well as microscopic inspection as endpoints. Genotoxicity of water, pore water, sediments, and SPM were assessed using the Ames test. Different extraction methods (Soxhlet extraction with solvents of variable polarity as well as a fluid/fluid extraction according to pH) in addition to a supplementation of biotests with S9 fractions from the liver of ,-naphthoflavone/phenobarbital-induced rats allowed a further characterization of the biological damage. Both sediments and SPM extracts caused cytotoxic effects in RTG-2 cells. Cytotoxicity was found to increase significantly with polarity of extracting solvents (NR50 = effective concentration for 50% cell death in the neutral red test: 80 [65], 100 [70], 180 [220], and 225 [270] mg/ml for ethanol, acetone, dichloromethane, and n -hexane extracts, respectively, if measured with [without] S9 supplementation). Following extraction according to pH, cytotoxicity could be attributed mainly to neutral substances (NR50: 80 and 218 mg dry SPM/ml test medium for the neutral and the acid fractions, respectively), whereas the slightly acid and basic fractions already showed little or no cytotoxicity. Samples taken during the period of flood rise showed the highest cytotoxic activities. Cytotoxicity was significantly enhanced by the addition of S9 preparations. In contrast, no genotoxic activity was found in native surface waters, pore waters, and SPM. [source] Polypropylene glycol is a selective binding inhibitor for LTA and other structurally related TLR2 agonistsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 3 2008Christian Draing Abstract Polypropylene glycol (PPG) is commonly added to bacterial cultures to avoid foaming. However, lipoteichoic acid (LTA) from bacteria grown with PPG lacked cytokine-inducing potency in human blood. We tested the blocking efficacy of several glycols on the cytokine response to staphylococcal LTA in human blood. PPG 1200 was the most potent inhibitor tested, shown for TNF, IL-1,, IL-6, IL-8, IL-10 and TGF-, induction, and displayed no cytotoxic effects. TNF induction by Staphylococcus aureus or by Toll-like receptor (TLR)2 agonists (di- and triacylated lipopeptides and LTA) was also inhibited by PPG 1200, but not that induced by Escherichia,coli or TLR4 agonists. In flow cytometric studies, PPG-carrying nanobeads bound more rhodamine-labeled LTA than those with glycerol. Additionally, the methyl group peak in the 1H-NMR of LTA shifted after incubation with increasing PPG 1200 concentrations. Sequential incubation of polystyrene plates with LTA, then PPG 1200 and then blood, with washing steps in between, showed that LTA-induced TNF release was inhibited. But when PPG 1200 was pre-incubated with blood that was washed before LTA was added, TNF induction was not repressed, demonstrating that PPG binds LTA and not cellular structures. In summary, PPG 1200 is a novel inhibitor of cytokine induction by TLR2 agonists, which interferes directly with the ligands. [source] Comparison of the aggregation properties, secondary structure and apoptotic effects of wild-type, Flemish and Dutch N-terminally truncated amyloid , peptidesEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2001N. Demeester Abstract The Dutch (E22Q) and Flemish (A21G) mutations in the ,APP region of the amyloid precursor protein (APP) are associated with familial forms of Alzheimer dementia. However, patients with these mutations express substantially different clinical phenotypes. Therefore, secondary structure and cytotoxic effects of the three A,(12,42) variants [wild-type (WT), Dutch and Flemish] were tested. At a concentration of 5 µm the aggregation of these peptides followed the order: A,(1,42) WT > A,(12,42) WT > A,(12,42) Flemish >,A,(12,42) Dutch. The stability of the secondary structure of these peptides upon decreasing the trifluoroethanol (TFE) concentration in the buffer was followed by circular dichroism measurements. WT peptides progressively lost their ,-helical structure; this change occurred faster for both the Flemish and Dutch peptides, and at higher percentages of TFE in the buffer, and was accompanied by an increase in ,-sheet and random coil content. Apoptosis was induced in neuronal cells by the A,(12,42) WT and Flemish peptides at concentrations as low as 1,5 µm, as evidenced by propidium iodide (PI) staining, DNA laddering and caspase-3 activity measurements. Even when longer incubation times and higher peptide concentrations were applied the N-truncated Dutch peptide did not induce apoptosis. Apoptosis induced by the full length A,(1,42) peptide was weaker than that induced by its N-truncated variant. These data suggest that N-truncation enhanced the cytotoxic effects of A, WT and Flemish peptides, which may play a role in the accelerated progression of dementia. [source] Effect of ozone on oral cells compared with established antimicrobialsEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 5 2006Karin C. Huth Ozone has been proposed as an alternative antiseptic agent in dentistry based on reports of its antimicrobial effects in both gaseous and aqueous forms. This study investigated whether gaseous ozone (4 × 106 µg m,3) and aqueous ozone (1.25,20 µg ml,1) exert any cytotoxic effects on human oral epithelial (BHY) cells and gingival fibroblast (HGF-1) cells compared with established antiseptics [chlorhexidine digluconate (CHX) 2%, 0.2%; sodium hypochlorite (NaOCl) 5.25%, 2.25%; hydrogen peroxide (H2O2) 3%], over a time of 1 min, and compared with the antibiotic, metronidazole, over 24 h. Cell counts, metabolic activity, Sp-1 binding, actin levels, and apoptosis were evaluated. Ozone gas was found to have toxic effects on both cell types. Essentially no cytotoxic signs were observed for aqueous ozone. CHX (2%, 0.2%) was highly toxic to BHY cells, and slightly (2%) and non-toxic (0.2%) to HGF-1 cells. NaOCl and H2O2 resulted in markedly reduced cell viability (BHY, HGF-1), whereas metronidazole displayed mild toxicity only to BHY cells. Taken together, aqueous ozone revealed the highest level of biocompatibility of the tested antiseptics. [source] Trichocladinols A,C, Cytotoxic Metabolites from a Cordyceps -Colonizing Ascomycete Trichocladium opacumEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 32 2009Huijuan Guo Abstract Trichocladinols A,C (1,3), three new metabolites, and the known massarigenin A (4), have been isolated from cultures of a Cordyceps -colonizing ascomycete Trichocladium opacum. Their structures were elucidated by NMR spectroscopy and X-ray crystallography. The absolute configuration of 1 was assigned by using the modified Mosher method and that of 3 was determined by X-ray crystallographic analysis of its (S)-MTPA ester. Compounds 1,3 showed modest cytotoxic effects against the human tumor cell lines HeLa and MCF-7. Structurally, compounds 1 and 2 possess a previously undescribed 2,9-dioxatricyclo[5.2.1.03,8]dec-4-ene skeleton.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Gene expression silencing with ,specific' small interfering RNA goes beyond specificity , a study of key parameters to take into account in the onset of small interfering RNA off-target effectsFEBS JOURNAL, Issue 11 2008Sébastien Vankoningsloo RNA-mediated gene silencing (RNA interference) is a powerful way to knock down gene expression and has revolutionized the fields of cellular and molecular biology. Indeed, the transfection of cultured cells with small interfering RNAs (siRNAs) is currently considered to be the best and easiest approach to loss-of-function experiments. However, several recent studies underscore the off-target and potential cytotoxic effects of siRNAs, which can lead to the silencing of unintended mRNAs. In this study, we used a low-density microarray to assess gene expression modifications in response to five different siRNAs in various cell types and transfection conditions. We found major differences in off-target signature according to: (a) siRNA sequence; (b) cell type; (c) duration of transfection; and (d) post-transfection time before analysis. These results contribute to a better understanding of important parameters that could impact on siRNA side effects in knockdown experiments. [source] Capsosomes with Multilayered Subcompartments: Assembly and Loading with Hydrophobic CargoADVANCED FUNCTIONAL MATERIALS, Issue 1 2010Leticia Hosta-Rigau Abstract Therapeutic artificial cells or organelles are nanoengineered vehicles that are expected to substitute for missing or lost cellular function. The creation of capsosomes, polymer carrier capsules containing liposomal subcompartments, is a promising approach towards constructing such therapeutic devices using the layer-by-layer assembly method. Herein, the assembly of intact, nonaggregated capsosomes containing multiple liposome layers is reported. It is also further demonstrated that thiocoraline, a hydrophobic model peptide with antitumor activity, can be efficiently loaded into the membrane of the liposomal subcompartments of the capsosomes. Cell viability assays verify the activity of the trapped antitumor cargo. It is also shown that pristine capsosomes do not display inherent cytotoxic effects. The ability to tune the number of liposome layers and hence the drug loading in capsosomes as well as their noncytotoxicity provide new opportunities for the creation of therapeutic artificial cells and organelles. [source] Biocompatible, Luminescent Silver@Phenol Formaldehyde Resin Core/Shell Nanospheres: Large-Scale Synthesis and Application for In Vivo Bioimaging,ADVANCED FUNCTIONAL MATERIALS, Issue 6 2008Shi-Rui Guo Abstract Biocompatible and green luminescent monodisperse silver/phenol formaldehyde resin core/shell spheres with controllable sizes, in the range of 180 to 1000 nm, and interesting architectures (centric, eccentric, and coenocytic core/shell spheres) have been synthesized by a facile one-step hydrothermal approach. These spheres can be used as bioimaging labels for human lung cancer H1299 cells. The results demonstrate that the nanoparticles can be internalized into cells and exhibit no cytotoxic effects, showing that such novel biocompatible core/shell structures can potentially be used as in vivo bioimaging labels. This facile one-pot polymerization and encapsulation technique may provide a useful tool to synthesize other core/shell particles that have potential application in biotechnology. [source] Bid-dependent generation of oxygen radicals promotes death receptor activation,induced apoptosis in murine hepatocytesHEPATOLOGY, Issue 2 2004Wen-Xing Ding Activation of tumor necrosis factor receptor 1 or Fas leads to the generation of reactive oxygen species, which are important to the cytotoxic effects of tumor necrosis factor , (TNF-,) or Fas ligand. However, how these radicals are generated following receptor ligation is not clear. Using primary hepatocytes, we found that TNF-, or anti,Fas antibody,induced burst of oxygen radicals was mainly derived from the mitochondria. We discovered that Bid,a pro-death Bcl-2 family protein activated by ligated death receptors,was the main intracellular molecule signaling the generation of the radicals by targeting to the mitochondria and that the majority of oxygen radical production was dependent on Bid. Reactive oxygen species contributed to cell death and caspase activation by promoting FLICE-inhibitory protein degradation and mitochondrial release of cytochrome c. For the latter part, the oxygen radicals did not affect Bak oligomerization but instead promoted mitochondrial cristae reorganization and membrane lipid peroxidation. Antioxidants could reverse these changes and therefore protect against TNF-, or anti,Fas-induced apoptosis. In conclusion, our studies established the signaling pathway from death receptor engagement to oxygen radical generation and determined the mechanism by which reactive oxygen species contributed to hepatocyte apoptosis following death receptor activation. (HEPATOLOGY 2004;40:403,413.) [source] The cytotoxic effects of resin-based sealers on dental pulp stem cellsINTERNATIONAL ENDODONTIC JOURNAL, Issue 8 2010O. Trubiani Trubiani O, Caputi S, Di Iorio D, D'Amario M, Paludi M, Giancola R, Di Nardo Di Maio F, De Angelis F, D'Arcangelo C. The cytotoxic effects of resin-based sealers on dental pulp stem cells. International Endodontic Journal. Abstract Aim, To evaluate the effect of four current resin-based adhesives on expanded ex vivo human dental pulp mesenchymal stem cells (DP-MSCs). Methodology, Dental pulp mesenchymal stem cells were derived from dental pulps of ten donors. After in vitro isolation, dental pulp stem cells were analysed using flow cytometry. The immunophenotype of DP-MSCs disclosed the homogeneous expression of the mesenchymal-related antigens CD29, CD44, CD73, CD90, CD105, CD166. DP-MSCs were exposed to four different commercially available bonding systems (CMF Bond, Prime&Bond NT, Clearfil S3 Bond, XP Bond), and after 24, 48 and 72 h of incubation the morphological features and the cell growth were analysed. Moreover, the cell viability was evaluated at the same times by MTT assay. Data were statistically analysed using a two-way anova and Holm,Sidak method (, set at 0.05). Results, Significant differences were observed between the four groups when comparing DP-MSCs appearance. DP-MSCs survived and proliferated without inhibition in the presence of CMF Bond adhesive. On the contrary, microscopic evaluation of the other three groups revealed extensive cytotoxic effects from the dentine bonding agents. The MTT assay revealed no statistically significant differences in cell viability after 72 h between the control group and CMF Bond group. All the other experimental groups had statistically lower optical density values. Conclusions, CMF Bond adhesive allowed human dental pulp stem cells to survive and proliferate. All of the other dentine bonding agents had extensive cytotoxic effects. [source] Cytotoxicity analysis of EDTA and citric acid applied on murine resident macrophages cultureINTERNATIONAL ENDODONTIC JOURNAL, Issue 5 2007K. F. Amaral Abstract Aim, To assess the ex vivo cytotoxicity of EDTA and citric acid solutions on macrophages. Methodology, The cytotoxicity of 17% EDTA and 15% citric acid was evaluated on murine macrophage cultures using MTT-Tetrazolium method [3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide]. A total of 5 × 105 cells were plated in medium culture with 17% EDTA or 15% citric acid. Fresh medium was used as a control. Toxicity values were analysed statistically by anova and Tukey's test (P < 0.05) at short (0, 6, 12, 24 h) and medium periods (1, 3, 5, 7 days), using ELISA absorbance. Results, On the short term, both EDTA (0.253 nm) and citric acid (0.260 nm) exhibited cytotoxic effects on macrophage cultures (P < 0.05). On the medium term, statistical differences were observed (P < 0.05) between the groups. EDTA (0.158 nm) and citric acid (0.219 nm) were cytotoxic when compared with the control group; EDTA-reduced macrophage viability significantly more than citric acid (P < 0.05). Conclusions, Both EDTA and citric acid had effects on macrophages cells ex vivo, but citric acid was less toxic in periods from 1 to 7 days of use. [source] Cytotoxicity of MTA and Portland cement on human ECV 304 endothelial cellsINTERNATIONAL ENDODONTIC JOURNAL, Issue 9 2005G. De Deus Abstract Aim, To evaluate the cytotoxic effects of two brands of mineral trioxide aggregate (MTA) (Pro-Root MTA® and MTA Angelus®) and Portland cement (PC) on the human ECV 304 endothelial cell line. Methodology, Endothelial ECV 304 cells were incubated at 37 °C in an atmosphere of 95% air, 5% carbon dioxide and 100% humidity for 7 days and grown in F12 medium supplemented with 10% fetal bovine serum with 50 ,g mL,1 of gentamicin sulphate. Effects of the materials on mitochondrial functions were measured by a colorimetric assay. At each experimental time interval (24, 48 and 72 h), a dimethyl-thiazol-diphenyl tetrazolium bromid assay was conducted to measure cell viability. All assays were repeated three times to ensure reproducibility. Results were expressed as average absorbance (A570\,nm) ± SD and the data were analysed statistically by one-way analysis of variance and the Bonferroni post-test. A P -value <0.05 was considered statistically significant. Results, No statistically significant difference was shown between any of the experimental materials (P > 0.05). Conclusions, The two brands of MTA analysed, as well as the PC, initially showed a similar elevated cytotoxic effect that decreased gradually with time allowing the cell culture to become reestablished. [source] Cytotoxicity of substances leached or dissolved from pulp capping materialsINTERNATIONAL ENDODONTIC JOURNAL, Issue 8 2005B. N. Cavalcanti Abstract Aim, To evaluate the cytotoxic effects of substances leached or dissolved from pulp capping materials on human pulp fibroblasts. Methodology, The substances were applied to cell cultures in conditioned media. The experimental groups were: GI (control; n = 24) , cultures treated with fresh medium; GII (n = 24) , cultures treated with calcium hydroxide cement; GIII (n = 24) , cultures treated with adhesive resin and GIV (n = 24) , cultures treated with 37% orthophosphoric acid. The media were conditioned by placing the crude materials in contact with fresh culture medium for 1 h. The cytotoxicity analysis was performed using the Trypan blue dye exclusion assay at times of 0, 6, 12 and 24 h for cell viability assay, and at 1, 3, 5 and 7 days for survival assay. Data were treated by anova (P < 0.05) and Tukey's test (P < 0.05). Results, GI and II presented similar cell viability and cell growth. GIII and IV exhibited statistically significant lower percentages of cell viability: GIV only at the 0 h experimental time, whereas in GIII this viability markedly diminished reaching values of 10% by 12 h. Cell growth was impaired only in cultures of GIII. Conclusions, Substances dissolved from the adhesive system tested were cytotoxic for human dental pulp fibroblasts in culture, whilst substances leached from calcium hydroxide were biocompatible. [source] NO-sulindac inhibits the hypoxia response of PC-3 prostate cancer cells via the Akt signalling pathwayINTERNATIONAL JOURNAL OF CANCER, Issue 1 2009Grant D. Stewart Abstract Nitric oxide-donating non-steroidal anti-inflammatory drugs are safer than traditional NSAIDs and inhibit the growth of prostate cancer cells with greater potency than NSAIDs. In vivo, prostate cancer deposits are found in a hypoxic environment which induces resistance to chemotherapy. The aim of this study was to assess the effects and mechanism of action of a NO-NSAID called NO-sulindac on the PC-3 prostate cancer cell line under hypoxic conditions. NO-sulindac was found to have pro-apoptotic, cytotoxic, and anti-invasive effect on PC-3 cells under normoxia and hypoxia. NO-sulindac was significantly more cytotoxic than sulindac at all oxygen levels. The sulindac/linker and NO-releasing subunits both contributed to the cytotoxic effects of NO-sulindac. Resistance of PC-3 cells to NO-sulindac was induced as the oxygen concentration declined. Hypoxia-induced chemoresistance was reversed by knocking-down hypoxia-inducible factor-1, (HIF-1,) mRNA using RNAi. Nuclear HIF-1, levels were upregulated at 0.2% oxygen but reduced by treatment with NO-sulindac, as was Akt phosphorylation. NO-sulindac treatment of hypoxic PC-3 cells transfected with a reporter construct, downregulated activation of the hypoxia response element (HRE) promoter. Co-transfection of PC-3 cells with the HRE promoter reporter construct and myr-Akt (constitutively active Akt) plasmids reversed the NO-sulindac induced reduction in HRE activation. Real-time polymerase chain reaction analysis of hypoxic, NO-sulindac treated PC-3 cells showed downregulation of lysyl oxidase and carbonic anhydrase IX mRNA expression. Collectively, these novel findings demonstrate that NO-sulindac directly inhibits the hypoxia response of PC-3 prostate cancer cells by inhibiting HIF-1, translation via the Akt signalling pathway. The ability of NO-sulindac to inhibit tumour adaption to hypoxia has considerable relevance to the future management of prostate cancer with the same cellular properties as PC-3. © 2008 Wiley-Liss, Inc. [source] Anti-tumor efficacy of the nucleoside analog 1-(2-deoxy-2-fluoro-4-thio-,-D-arabinofuranosyl) cytosine (4,-thio-FAC) in human pancreatic and ovarian tumor xenograft modelsINTERNATIONAL JOURNAL OF CANCER, Issue 6 2005Deborah A. Zajchowski Abstract 1-(2-Deoxy-2-fluoro-4-thio-,- D -arabinofuranosyl) cytosine (4,-thio-FAC) is a deoxycytidine analog that has been shown previously to have impressive anti-proliferative and cytotoxic effects in vitro and in vivo toward colorectal and gastric tumors. In our present studies, the pharmacokinetic behavior in nude mice and the effectiveness of 4,-thio-FAC against human pancreatic and ovarian tumor growth were assessed in comparison with standard chemotherapeutic agents. Potent in vitro anti-proliferative effects were observed against pancreatic (Capan-1, MIA-PaCa-2, BxPC-3) and ovarian (SK-OV-3, OVCAR-3, ES-2) cancer cell lines with IC50 of 0.01,0.2 ,M. In vivo anti-tumor activity was evaluated in nude mice bearing subcutaneously (s.c.) implanted human pancreatic tumor xenografts or intraperitoneally (i.p.) disseminated human ovarian xenografted tumors. Oral daily administration of 4,-thio-FAC for 8,10 days significantly inhibited the growth of gemcitabine-resistant BxPC-3 pancreatic tumors and induced regression of gemcitabine-refractory Capan-1 tumors. 4,-Thio-FAC was also a highly effective inhibitor of ovarian peritoneal carcinomatosis. In the SK-OV-3 and ES-2 ovarian cancer models, 4,-thio-FAC prolonged survival to a greater extent than that observed with gemcitabine. Furthermore, the superiority of 4,-thio-FAC to carboplatin and paclitaxel was demonstrated in the ES-2 clear cell ovarian carcinoma model. Studies provide evidence that 4,-thio-FAC is a promising new alternative to gemcitabine and other chemotherapeutic drugs in the treatment of a variety of tumor indications, including pancreatic and ovarian carcinoma. © 2004 Wiley-Liss, Inc. [source] CD137 and CD137 ligand constitutively coexpressed on human T and B leukemia cells signal proliferation and survivalINTERNATIONAL JOURNAL OF CANCER, Issue 3 2004Carla Palma Abstract CD137, a member of the tumor necrosis factor receptor family, provides expansion and survival signal to T cells. Its ligand, CD137L, in addition to its ability to costimulate T cells, signals back into antigen presenting cells promoting their activation and differentiation. Recently, CD137 has been proposed as a therapeutic target to improve and sustain anticancer immune response. Several activated T leukemia and B lymphoma cell lines expressed CD137 or CD137L, respectively, and soluble CD137L has been found in sera of leukemia patients. However, the functionality and role of these costimulatory molecules in hematologic malignancies are until now unknown. Interestingly, we observed constitutive CD137 and CD137L coexpression on both human T and B leukemia cell lines. The constitutive CD137 expression on unstimulated T or B leukemia cells presents some differences compared to CD137 expressed on PMA/ionomycin-activated T leukemia cells. Surprisingly, in spite of the low expression level, both tumor CD137 and CD137L molecules signaled in T and B leukemia cells inducing proliferation and prolonging survival. In addition, CD137/CD137L system ligation opposed the anticancer drug cytotoxic effects, reducing the apoptotic DNA fragmentation and stimulating proliferation of doxorubicin-escaped leukemia cells. Although the role of leukemia CD137/CD137L system in vivo is unknown, these data suggest that these costimulatory molecules might confer an advantage to hematologic tumors promoting survival, sustaining cellular growth and contributing to drug resistance. © 2003 Wiley-Liss, Inc. [source] | |||||||||||||||||||||||||||||||||||||