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Xiaoxi Yang, Wenting Song, Na Liu, Zhendong Sun, Ruirui Liu, Qian S Liu, Qunfang Zhou, Guibin Jiang
Synthetic phenolic antioxidants (SPAs) are closely correlated with human life due to their extensive usages, and increasing concerns have been raised on their biosafety. The previous controversial findings caused continuous debates on their potential endocrine disrupting effects. In the present study, four commonly used SPAs, including butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tert-butyl hydroquinone (TBHQ) and 2,2'-methylenebis(6-tert-butyl-4-methylphenol) (AO2246), were investigated for their estrogenic effects, and the results from in vitro screening assays showed SPAs themselves had negligible estrogen receptor binding affinities...
December 13, 2017: Environmental Science & Technology
Shaoyun Chen, Hairong Liang, Gonghua Hu, Hui Yang, Kairu Zhou, Longmei Xu, Jiaxian Liu, Bei Lai, Li Song, Hao Luo, Jianming Peng, Zhidong Liu, Yongmei Xiao, Wen Chen, Huanwen Tang
Previous studies have shown that long noncoding RNAs (lncRNAs) were related to human carcinogenesis and might be designated as diagnosis and prognosis biomarkers. Hydroquinone (HQ), as one of the metabolites of benzene, was closely relevant to occupational benzene poisoning and occupational leukemia. Using high-throughput sequencing technology, we investigated differences in lncRNA and mRNA expression profiles between experimental group (HQ 20 μmol/L) and control group (PBS). Compared to control group, a total of 65 lncRNAs and 186 mRNAs were previously identified to be aberrantly expressed more than two fold change in experimental group...
November 10, 2017: Oncotarget
Richard C Petersen
A breakthrough has been discovered in pathology chemistry related to increasing molecular structure that can interfere with oxygen diffusion through cell membranes. Free radicals can crosslink unsaturated low-viscosity fatty acid oils by chain-growth polymerization into more viscous liquids and even solids. Free radicals are released by mitochondria in response to intermittent hypoxia that can increase membrane molecular organization to reduce fluidity and oxygen diffusion in a possible continuing vicious cycle toward pathological disease...
2017: AIMS Biophysics
Gwang Hoon Kim, Kyung Ah Cheong, Ai-Young Lee
Background: Hydroquinone (HQ) is frequently combined with retinoic acid (RA) to enhance lightening efficacy, which may also affect skin irritancy. Although skin irritation leads to postinflammatory hyperpigmentation, little research has been performed to compare skin irritancy between each component and the combination. Objective: This study was done to examine whether HQ-RA combination increased skin irritation induced by HQ or RA alone. Methods: Patch testing was performed using maximum therapeutic and higher concentrations of HQ and RA in 10 volunteers, and then, it was performed using their popular therapeutic concentrations and combination in the other 20 volunteers...
December 2017: Annals of Dermatology
Colin W Anson, Shannon S Stahl
The molecular cobalt complex, Co(salophen), and para-hydroquinone (H2Q) serve as effective cocatalysts for the electrochemical reduction of O2 to water. Mechanistic studies reveal redox cooperativity between Co(salophen) and H2Q. H2Q serves as an electron-proton transfer mediator (EPTM) that enables electrochemical O2 reduction at higher potentials and with faster rates than is observed with Co(salophen) alone. Replacement of H2Q with the higher-potential EPTM, 2-chloro-H2Q, allows for faster O2 reduction rates at higher applied potential...
December 3, 2017: Journal of the American Chemical Society
Rika Nakai, Shun Fukuda, Masaya Kawase, Yoko Yamashita, Hitoshi Ashida
Certain dioxins, including 2,3,7,8,-tetrachloro-dibenzo-p-dioxin (TCDD), are exogenous ligands for an aryl hydrocarbon receptor (AhR) and induces various drug-metabolizing enzymes. In this study, we examined the effect of curcumin on expression of drug-metabolizing enzymes through the AhR and NF-E2 related factor 2 (Nrf2) pathways. Curcumin dose-dependently inhibited TCDD-induced expression of phase I enzyme cytochrome P450 1A1 (CYP1A1) and phase II enzymes NAD(P)H:quinone oxidoreductase-1 (NQO1) and heme oxygenase 1 (HO-1) but not tert-butyl hydroquinone-induced NQO1 and HO-1, suggesting that curcumin inhibited only AhR pathway, but not Nrf2 one directly...
December 1, 2017: Bioscience, Biotechnology, and Biochemistry
Xiaoyong Luo, Zhihang Liu, Yukari Sunohara, Hiroshi Matsumoto, Pingliang Li
In order to understand the action mechanism of fluazifop-P-butyl (FB) in bristly starbur (Acanthospermum hispidum D.C.), a susceptible plant, the role of active oxygen species (ROS) in herbicide-induced cell death in shoots was investigated. FB-induced phytotoxicity was not reduced by the antioxidants, 1,4-diazabicyclooctane (dabaco), sodium azide, l-tryptophan, d-tryptophan, hydroquinone and dimethyl pyridine N-oxide (DMPO). The activities of superoxide dismutase (SOD) and catalase (CAT), in bristly starbur seedlings were significantly increased by FB at 12 HAT and 24 HAT, while ascorbate peroxidase (APX) and glutathione reductase (GR) activities increased only at 12 HAT...
November 2017: Pesticide Biochemistry and Physiology
Vanessa N Lima, Carmen S D Rodrigues, Luis M Madeira
The aim of this study was to assess the degradation and mineralization of hydroquinone (HQ) by the Fenton's process in a bubble column reactor (BCR). The effect of the main operating variables, namely, air flow rate, effluent volume, hydrogen peroxide (H2O2) concentration, catalyst (Fe2+) dose, initial pH, and temperature, were assessed. For all air flow rates tested, no concentration gradients along the column were noticed, evidencing that a good mixing was reached in the BCR. For the best conditions tested ([H2O2] = 500 mg/L, [Fe2+] = 45 mg/L, T = 24 °C, Q air = 2...
November 27, 2017: Environmental Science and Pollution Research International
Marcin Sarewicz, Łukasz Bujnowicz, Artur Osyczka
One of the less understood parts of the catalytic cycle of cytochrome bc1/b6f complexes is the mechanism of electronic bifurcation occurring within the hydroquinone oxidation site (Qo site). Several models describing this mechanism invoke a phenomenon of formation of an unstable semiquinone. Recent studies with isolated cytochrome bc1 or b6f revealed that a relatively stable semiquinone spin-coupled to the reduced Rieske cluster (SQ-FeS) is generated at the Qo site during the oxidation of ubi- or plastohydroquinone analogs under conditions of continuous turnover...
November 24, 2017: Biochimica et Biophysica Acta
F Miao, T C Lei, M Y Su, W J Yi, S Jiang, S Z Xu
Objective: To compare the decolorization efficiency of lignin peroxidase (LiP), manganese peroxidase (MnP) and laccase on eumelanin and pheomelanin, and to investigate the effect of topical administration of LiP solution on hyperpigmented guinea pigs skin induced by 308 nm excimer light. Methods: Pheomelanin-enriched specimens were prepared from human hair and cutaneous melanoma tissue using alkaline lysis method.Synthetic eumelanin was purchased from a commercial supplier.The same amount (0.02%) of melanin was incubated with the equal enzyme activity (0...
November 21, 2017: Zhonghua Yi Xue za Zhi [Chinese medical journal]
Jie Li, Xiumei Xing, Xinjie Zhang, Boxuan Liang, Zhini He, Chen Gao, Shan Wang, Fangping Wang, Haiyan Zhang, Shan Zeng, Junling Fan, Liping Chen, Zhengbao Zhang, Bo Zhang, Caixia Liu, Qing Wang, Weiwei Lin, Guanghui Dong, Huanwen Tang, Wen Chen, Yongmei Xiao, Daochuan Li
In this study, we explore whether altered global histone modifications respond to low-level benzene exposure as well as their association with the hematotoxicity. We recruited 147 low-level benzene-exposed workers and 122 control workers from a petrochemical factory in Maoming City, Guangdong Province, China. The internal exposure marker level, urinary S-phenylmercapturic acid (SPMA), in benzene-exposed workers was 1.81-fold higher than that of the controls (P < 0.001). ELISA method was established to examine the specific histone modifications in human peripheral blood lymphocytes (PBLCs) of workers...
November 22, 2017: Environmental Pollution
Carmen S D Rodrigues, Ricardo A C Borges, Vanessa N Lima, Luis M Madeira
This paper reports on a study of the oxidation of p-nitrophenol (PNP) in a bubble column reactor (BCR). The use of the air stream aimed to provide perfect mixing in the liquid phase, which was successfully achieved and checked experimentally; there were no concentration gradients along the column, even at the lowest air flow rate used (Q = 1 mL/min at room temperature and atmospheric pressure). The effect of the operating variables was assessed, and a total reduction of PNP was reached, as well as mineralization of 49...
November 20, 2017: Journal of Environmental Management
Renata Szymańska, Jerzy Kruk
The data presented indicate that there is a variety of unique prenyllipids, often of very limited taxonomic distribution, whose origin, biosynthesis, metabolism and biological function deserves to be elucidated. These compounds include tocoenols, tocochromanol esters, tocochromanol acids, plastoquinones and ubiquinones. Additionally, based on the available data, it can be assumed that there are still unrecognized prenyllipids, like prenylquinols fatty acid esters of the hydroquinone ring, including prenylquinol phosphates, and others, whose biological function might be of great importance...
November 14, 2017: Plant Physiology and Biochemistry: PPB
Sherry R Black, Timothy R Fennell, James M Mathews, Rodney W Snyder, Purvi R Patel, Scott L Watson, Vicki Sutherland, Suramya Waidyanatha
1. Hydroquinone (HQ) is present in some foods and has varied industrial, medical and consumer uses. These studies were undertaken to investigate the disposition of HQ in rats and mice following gavage, intravenous (IV) and dermal exposure. 2. [(14 )C]HQ administered (0.5, 5 or 50 mg/kg) by gavage or IV routes to male and female Harlan Sprague-Dawley (HSD) rats and B6C3F1/N mice was well absorbed and rapidly excreted primarily in urine. Radioactivity remaining in tissues at 72 h was <1% for both species at all dose levels and routes...
November 22, 2017: Xenobiotica; the Fate of Foreign Compounds in Biological Systems
Liuchuan Tong, Qing Chen, Andrew A Wong, Rafael Gómez-Bombarelli, Alán Aspuru-Guzik, Roy G Gordon, Michael J Aziz
Quinone-based aqueous flow batteries provide a potential opportunity for large-scale, low-cost energy storage due to their composition from earth abundant elements, high aqueous solubility, reversible redox kinetics and their chemical tunability such as reduction potential. In an operating flow battery utilizing 9,10-anthraquinone-2,7-disulfonic acid, the aggregation of an oxidized quinone and a reduced hydroquinone to form a quinhydrone dimer causes significant variations from ideal solution behavior and of optical absorption from the Beer-Lambert law...
November 22, 2017: Physical Chemistry Chemical Physics: PCCP
Ying-Xu Chen, Wen-Jing Zhang, Ke-Jing Huang, Mingbo Zheng, Ya-Cen Mao
In this work, we report an ultrasensitive electrochemical biosensor for microRNA-21 (miRNA-21) detection by using a competitive RNA-RNA hybridization configuration. A biotinylated miRNA of the self-same sequence with the target miRNA is mixed with the samples, and allowed competition with the target miRNA for a thiolated RNA probe immobilized onto a tungsten diselenide (WSe2) nanosheet modified electrode. Thereafter the current response is obtained by forming the hybridized biotinylated miRNA with streptavidin-horseradish peroxidase (HRP) conjugates to catalyze the H2O2 + hydroquinone (HQ) system...
November 21, 2017: Analyst
B К Semin, L N Davletshina, M Seibert, A B Rubin
Extraction of Mn cations from the oxygen-evolving complex (OEC) of Ca-depleted PSII membranes (PSII[-Ca,4Mn]) by reductants like hydroquinone (H2Q) occurs with lower efficiency at acidic pH (2Mn/reaction center [RC] are extracted at pH5.7) than at neutral pH (3Mn/RC are extracted at pH6.5) [Semin et al. Photosynth. Res. 125 (2015) 95]. Fe(II) also extracts Mn cations from PSII(-Ca,4Mn), but only 2Mn/RC at pH6.5, forming a heteronuclear 2Mn/2Fe cluster [Semin and Seibert, J. Bioenerg. Biomembr. 48 (2016) 227]...
November 11, 2017: Journal of Photochemistry and Photobiology. B, Biology
F Ly, P Diousse, C Ndiaye, A Déme, B A Diatta, M T Ndiaye, M Diallo, A Diop, A D Kebe, F Fall, A Kane
BACKGROUND: The cosmetic use of bleaching products is common among women from sub-Saharan Africa. The most frequently used products are highly potent corticosteroids (clobetasol propionate) and hydroquinone. Herein, we report 8 cases of SCC in women using skin bleaching products for cosmetic purposes. Our aim is to describe the epidemiological, clinical and pathological aspects of the carcinomas observed during the course of skin lightening. METHODS: We conducted a descriptive multicentre study from August 2005 to January 2016 in three dermatology units in Senegal...
November 14, 2017: Annales de Dermatologie et de Vénéréologie
Monique J Vanaman Wilson, Isabela T Jones, Joanna Bolton, Lisa Larsen, Douglas C Wu, Mitchel P Goldman
<p>Purpose: Though hydroquinone (HQ) remains the gold standard for treatment of hyperpigmentation, concerns about its safety have prompted the development of HQ-free topical skin lightening systems. OBJECTIVE: To compare the efficacy and tolerability of a new HQ-free system and a popular HQ-based system for the improvement of facial hyperpigmentation and photoaging in darker skin types. METHODS: This investigator-blinded trial randomized 30 subjects of Fitzpatrick skin types III to VI with moderate to severe hyperpigmentation to a new 7-product HQ-free system or a 7-product HQ-based system for 12 weeks...
November 1, 2017: Journal of Drugs in Dermatology: JDD
Rossana Del Vecchio, Tara Marie Schendorf, Neil V Blough
The molecular basis of the optical properties of chromophoric dissolved organic matter (CDOM) and humic substances (HS) remains poorly understood and yet to be investigated adequately. This study evaluates the relative contributions of two broad classes of carbonyl-containing compounds, ketones/aldehydes versus quinones, to the absorption and emission properties of a representative suite of HS as well as a lignin sample. Selective reduction of quinones to hydroquinones by addition of small molar excesses of dithionite to these samples under anoxic conditions produced small or negligible changes in their optical properties; however, when measurable, these changes were largely reversible upon exposure to air, consistent with the reoxidation of hydroquinones to quinones...
November 20, 2017: Environmental Science & Technology
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