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Oxygen toxicity

Marika Rai, David Spratt, Paola R Gomez-Pereira, Jay Patel, Sean P Nair
Oral malodour is a common condition which affects a large proportion of the population, resulting in social, emotional and psychological stress. Certain oral bacteria form a coating called a biofilm on the tongue dorsum and degrade organic compounds releasing volatile sulfur compounds that are malodourous. Current chemical treatments for oral malodour such as mouthwashes containing chlorhexidine or essential oils, are not sufficiently effective at reducing the bacterial load on the tongue. One potential alternative to current chemical treatments for oral malodour is the use of light activated antimicrobial agents (LAAAs), which display no toxicity or antimicrobial activity in the dark, but when exposed to light of a specific wavelength produce reactive oxygen species which induce damage to target cells in a process known as photodynamic inactivation...
October 18, 2016: Journal of Breath Research
Takashi Ishida, Sachie Suzuki, Chen-Yi Lai, Satoshi Yamazaki, Shigeru Kakuta, Yoichiro Iwakura, Masanori Nojima, Yasuo Takeuchi, Masaaki Higashihara, Hiromitsu Nakauchi, Makoto Otsu
Hematopoietic stem cell (HSC) transplantation (HSCT) for malignancy requires toxic pre-conditioning to maximize anti-tumor effects and donor-HSC engraftment. While this induces bone marrow (BM)-localized inflammation, how this BM environmental change affects transplanted HSCs in vivo remains largely unknown. We here report that, depending on interval between irradiation and HSCT, residence within lethally irradiated recipient BM compromises donor-HSC reconstitution ability. Both in vivo and in vitro we demonstrate that, among inflammatory cytokines, TNF-α plays a role in HSC damage: TNF-α stimulation leads to accumulation of reactive oxygen species (ROS) in highly purified hematopoietic stem/progenitor cells (HSCs/HSPCs)...
October 18, 2016: Stem Cells
Jie Li, Yanli Zhang, Xianhui Cai, Qingqing Xia, Jingmeng Chen, Yi Liao, Zuguo Liu, Yalin Wu
Effective clearance of all-trans-retinal (atRAL) from retinal pigment epithelial (RPE) cells is important for avoiding its cytotoxicity. However, the metabolism of atRAL in RPE cells is poorly clarified. The present study was designed to analyze metabolic products of atRAL and to compare the cytotoxicity of atRAL versus its derivative all-trans-retinal dimer (atRAL-dimer) in human RPE cells. We found that all-trans-retinol (atROL) and a mixture of atRAL condensation metabolites including atRAL-dimer and A2E were generated after incubating RPE cells with atRAL for 6h, and the amount of atRAL-dimer was significantly higher than that of A2E...
October 14, 2016: Toxicology
Yanqin Ma, Zhenhua Ma, Shuqin Yin, Xiaoyan Yan, Jundong Wang
Excessive amount of inorganic arsenic (iAs) and fluoride (F) coexist in drinking water in many regions, which is associated with high risk of vascular diseases. However, the underlying mechanisms are not well studied. The present study was to evaluate the effects of iAs and F individual or combined exposure on endothelial activation and apoptosis in vitro. Primary human umbilical vein endothelial cells (HUVECs) were exposed to 5 μM As2O3 and/or 1 mM NaF. Changes in endothelial cell apoptosis, inflammation, oxidative stress and nitric oxide (NO) production were analyzed...
October 14, 2016: Chemosphere
Fábio de Melo Tarouco, Filipe Guilherme Andrade de Godoi, Robson Rabelo Velasques, Amanda da Silveira Guerreiro, Marcio Alberto Geihs, Carlos Eduardo da Rosa
Glyphosate based herbicides, including Roundup, are widely employed in agriculture and urban spaces. The objective of this study was to evaluate the toxicological effects of Roundup on the estuarine polychaeta Laeonereis acuta. Biomarkers of oxidative stress as well as acetylcholinesterase and propionilcholinesterase activities were analyzed. Firstly, the LC50 96h for L. acuta was established (8.19mg/L). After, the animals were exposed to two Roundup concentrations: 3.25mg/L (non-observed effect concentration - NOEC) and 5...
October 14, 2016: Ecotoxicology and Environmental Safety
Maude St-Onge, Kurt Anseeuw, Frank Lee Cantrell, Ian C Gilchrist, Philippe Hantson, Benoit Bailey, Valéry Lavergne, Sophie Gosselin, William Kerns, Martin Laliberté, Eric J Lavonas, David N Juurlink, John Muscedere, Chen-Chang Yang, Tasnim Sinuff, Michael Rieder, Bruno Mégarbane
OBJECTIVE: To provide a management approach for adults with calcium channel blocker poisoning. DATA SOURCES, STUDY SELECTION, AND DATA EXTRACTION: Following the Appraisal of Guidelines for Research & Evaluation II instrument, initial voting statements were constructed based on summaries outlining the evidence, risks, and benefits. DATA SYNTHESIS: We recommend 1) for asymptomatic patients, observation and consideration of decontamination following a potentially toxic calcium channel blocker ingestion (1D); 2) as first-line therapies (prioritized based on desired effect), IV calcium (1D), high-dose insulin therapy (1D-2D), and norepinephrine and/or epinephrine (1D)...
October 3, 2016: Critical Care Medicine
Qin Wang, Katherine J Franz
Metal ions are essential for a wide range of physiological processes, but they can also be toxic if not appropriately regulated by a complex network of metal trafficking proteins. Intervention in cellular metal distribution with small-molecule or peptide chelating agents has promising therapeutic potential to harness metals to fight disease. Molecular outcomes associated with forming metal-chelate interactions in situ include altering the concentration and subcellular metal distribution, inhibiting metalloenzymes, enhancing the reactivity of a metal species to elicit a favorable biological response, or passivating the reactivity of a metal species to prevent deleterious reactivity...
October 17, 2016: Accounts of Chemical Research
Anliang Huang, Dan Yue, Danying Liao, Liuliu Cheng, Jinhu Ma, Yuquan Wei, Aiping Tong, Ping Cheng
Arsenic trioxide (ATO) has demonstrated clinical efficacy in acute promyelocytic leukemia (APL) and in vitro activity in various solid tumors. As2O3 as single agent exhibits poor efficacy for treatment of hepatocellular carcinoma (HCC) in phase II trial, suggesting that new modalities of treatment with enhanced therapeutic effect and alleviated toxicity are needed for application of As2O3 on patients with HCC. Survivin is the strongest inhibitor of apoptosis protein over-expressed in tumors, which has been proposed as an attractive target for new anticancer interventions...
October 11, 2016: Oncology Reports
Jyun-Wei Chen, Cheng-Chung Chang
Unlike traditional binary nanostructures that construct chemotherapy drugs and photodynamic therapy photosensitizers, we introduce a molecule possessing the chemo-photodynamic dual therapy function. A water-soluble aggregation-induced emission enhancement (AIEE) fluorogen, NV-12P, was designed and synthesized based on asymmetric 1, 6-disubstituted naphthalene and can generate particular reactive oxygen species (ROS) to undergo type I photodynamic therapy (PDT) programme under irradiation. Furthermore, this compound can specifically localize in mitochondria and, after biologically evaluation, cause mitochondrial dysfunction and potent cytotoxicity to cancer cells but not normal cells...
October 17, 2016: ACS Applied Materials & Interfaces
Leanne Stannard, Shareen H Doak, Ann Doherty, Gareth J Jenkins
Humans are exposed to carcinogens through air, water, food and tobacco smoke. Nickel chloride (NiCl2 ) is a toxic and carcinogenic environmental and occupational pollutant, which was previously classified as a non-genotoxic carcinogen, and thought to not directly alter the DNA. Non-genotoxic carcinogens like NiCl2 are difficult to detect in vitro, hence a heavy reliance on animal studies exists. NiCl2 has previously been classified as a non-genotoxic carcinogen (NGTC); however, after studying the effect of NiCl2 on many mechanistic endpoints, it has become clear that NiCl2 behaves more like a genotoxic carcinogen...
October 17, 2016: Basic & Clinical Pharmacology & Toxicology
Peter Husen, Ilia A Solov'yov
The homodimeric bc1 protein complex is embedded in membranes of mitochondria and photosynthetic bacteria, where it transports protons across the membrane to maintain an electrostatic potential used to drive ATP synthesis as part of the respiratory or photosynthetic pathways. The reaction cycle of the bc1 complex is driven by series of redox processes involving substrate molecules from the membrane, but occasional side reactions between an intermediate semiquinone substrate and molecular oxygen are suspected to be a source of toxic superoxide, which is believed to be a factor in aging...
October 17, 2016: Journal of Physical Chemistry. B
Jenny M Pedersen, Yoo-Sik Shim, Vaibhav Hans, Martin B Phillips, Jeffrey M Macdonald, Glenn Walker, Melvin E Andersen, Harvey J Clewell, Miyoung Yoon
Accurate prediction of metabolism is a significant outstanding challenge in toxicology. The best predictions are based on experimental data from in vitro systems using primary hepatocytes. The predictivity of the primary hepatocyte-based culture systems, however, is still limited due to well-known phenotypic instability and rapid decline of metabolic competence within a few hours. Dynamic flow bioreactors for three-dimensional cell cultures are thought to be better at recapitulating tissue microenvironments and show potential to improve in vivo extrapolations of chemical or drug toxicity based on in vitro test results...
2016: Frontiers in Bioengineering and Biotechnology
Ha Ryong Kim, Da Young Shin, Kyu Hyuck Chung
Polyhexamethylene biguanide (PHMB) is a member of the polymeric guanidine family, which is used as a biocide and preservative in industrial, medicinal, and consumer products. Some studies reported that polyhexamethylene guanidine phosphate, which is also a member of the guanidine family, induced severe inflammation and fibrosis in the lungs. However, limited studies have evaluated the pulmonary toxicity of PHMB associated with inflammatory responses. The aim of this study was to elucidate the inflammatory responses and its mechanisms induced by PHMB in lung cells...
October 13, 2016: Toxicology in Vitro: An International Journal Published in Association with BIBRA
Yuanyuan Chen, Jian Li, Jin Wei, Atufa Kawan, Li Wang, Xuezhen Zhang
Cyanobacterial blooms and their associated toxins pose a great threat to human beings. The situation is even worse for those whose drinking water source is a cyanotoxin-polluted water body. Therefore, efficient and safe treatments urgently need to be developed. The present study verified the application of vitamin C on the inhibition of toxic Microcystis aeruginosa. Our results showed that vitamin C drove the Fenton reaction and significantly sterilized cultures of M. aeruginosa. The algicidal activity of vitamin C was dependent on its involvement in iron (Fe) metabolism...
October 6, 2016: Journal of Hazardous Materials
Chengyu Wang, Yin Cheng, Hongyi Liu, Yaping Xu, Hu Peng, Juntian Lang, Jianchun Liao, Haibin Liu, Huanhai Liu, Jingping Fan
BACKGROUND/AIMS: Nasopharyngeal cancer (NPC) is one of the common human malignant diseases all over the world, and chemotherapy remains the main therapy for NPC. However, the survival and life quality of NPC patients are still very poor. Thus, novel and selective anti-tumor agents are pressingly needed. Our previous study identified pectolinarigenin as a novel effective anti-tumor drug candidate for NPC. In this study, we further investigated its anti-tumor activities and explored the potential molecular mechanism...
October 17, 2016: Cellular Physiology and Biochemistry
Pavlína Hašková, Hana Jansová, Jan Bureš, Miloslav Macháček, Anna Jirkovská, Katherine J Franz, Petra Kovaříková, Tomáš Šimůnek
Catecholamines may undergo iron-promoted oxidation resulting in formation of reactive intermediates (aminochromes) capable of redox cycling and reactive oxygen species (ROS) formation. Both of them induce oxidative stress resulting in cellular damage and death. Iron chelation has been recently shown as a suitable tool of cardioprotection with considerable potential to protect cardiac cells against catecholamine-induced cardiotoxicity. However, prolonged exposure of cells to classical chelators may interfere with physiological iron homeostasis...
October 12, 2016: Toxicology
Luciana Maria Ribeiro Antinarelli, Isabela de Oliveira Souza, Nicolas Glanzmann, Ayla das Chagas Almeida, Gabriane Nascimento Porcino, Eveline Gomes Vasconcelos, Adilson David da Silva, Elaine Soares Coimbra
In this study, we have investigated the antileishmanial activity of ten 7-chloro-4-quinolinylhydrazone derivatives. Among the compounds tested, compounds 2a and 2j presented activity against promastigotes (IC50 values of 52.5 and 21.1 μM, respectively) and compounds 2a and 2c were active against intracellular amastigotes (IC50 of 8.1 and 15.6 μM, respectively) of Leishmania amazonensis. The majority of compounds did not show toxicity against murine macrophages. Compound 2a exhibited low cytotoxicity to human erythrocytes and induced an oxidative imbalance in promastigote forms, reflected by an increase in the formation of reactive oxygen species (ROS) and a reduction of mitochondrial membrane potential...
October 12, 2016: Experimental Parasitology
Junguo Li, Bao Liu, Yanan Zeng, Ziming Wang
AOD (argon oxygen decarburization) slag, which is the by-product of the stainless steel refining process, is a recyclable slag because of its high content of calcium and silicon. The leaching toxicity cannot be ignored in the recycling process because the slag contains a certain amount of Cr. In this study, the mineral analysis, batch leaching tests and thermodynamic and kinetic modeling by PHREEQC combined with FactSage software were performed to explore the influence of the dissolution of primary minerals and the precipitation of secondary minerals on the elution of Cr from AOD slag...
October 11, 2016: Chemosphere
Madhuri A Inupakutika, Soham Sengupta, Amith R Devireddy, Rajeev K Azad, Ron Mittler
Reactive oxygen species (ROS) play a key role in the regulation of many biological processes in plants. Nonetheless, they are considered highly reactive and toxic to cells. Owing to their toxicity, as well as their important role in signaling, the level of ROS in cells needs to be tightly regulated. The ROS gene network, encoding a highly redundant arsenal of ROS scavenging mechanisms and an array of enzymes involved in ROS production, regulates ROS metabolism and signaling in plants. In this article, we review the role of the ROS gene network in plants and examine how it evolved...
October 14, 2016: Journal of Experimental Botany
Yingnan Han, Tong Liu, Jinhua Wang, Jun Wang, Cheng Zhang, Lusheng Zhu
Azoxystrobin is a frequently used fungicide in agriculture. Its toxicological effects on non-target organisms have aroused attention. In the present work, the toxic effects of azoxystrobin on zebrafish (Danio rerio) were investigated. Male and female zebrafish were separately exposed to a control solution and three azoxystrobin treatments (1, 10, and 100μg/L) and were sampled on days 7, 14, 21, and 28. Reactive oxygen species (ROS) were accumulated in excess in the zebrafish livers. Superoxide dismutase (SOD) activity was significantly inhibited in the male zebrafish...
October 2016: Pesticide Biochemistry and Physiology
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