- Novel miRNA biomarkers for genotoxicity screening in mouse
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The genotoxic potential of drugs is a serious problem, and its evaluation is one of the most critical processes of drug development. Although the comet assay of compound-exposed tissue is a frequently used genotoxicity test, its high false-positive rate is a major complication, and we consistently obtained false-positive results using the comet assay of mouse liver for nine hepatotoxic non-genotoxins (NGTXs). To identify novel genotoxin (GTX)-specific biomarkers, we screened the expression of 750 microRNAs (miRNAs) in the livers of mice treated with GTXs or NGTXs. Three miRNAs, miR-22-3p, miR-409-3p, and miR-543-3p, were significantly down-regulated in GTX-treated mouse liver. In contrast, these three miRNAs were significantly up-regulated in plasma. A discrimination model based on the expression levels of these biomarkers successfully identified GTXs and NGTXs. This novel biomarker expression-based discrimination model analysis using both liver and plasma is effective for detecting genotoxicity with high sensitivity and reliability to support drug development.
- Oka, Hiroyuki,Masuno, Koichi,Uehara, Takeki,Okamoto, Toru,Matsuura, Yoshiharu,Nakano, Toru,Yamaguchi, Shinpei
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- In vitro cytotoxic effects of DEHP-alternative plasticizers and their primary metabolites on a L929 cell line
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Phthalic acid esters have been widely used to improve the plasticity of PVC medical devices. They carry a high exposure risk for both humans and the environment in clinical situations. Our study focuses on the cytotoxicity of alternative plasticizers. Postulated primary metabolites were synthesized, not being commercially available. Cytotoxicity assays were performed on L929 murine cells according to the ISO-EN 10993-5 standard design for the biocompatibility of medical devices. The tested concentrations of plasticizers (0.01, 0.05 and 0.1 mg/ml) covered the range likely to be found in biological fluids coming into direct contact with the medical devices. DEHP, DINP and DINCH were cytotoxic at the highest concentration (0.1 mg/ml) for 7 days of exposure. Their corresponding metabolites were found to be more cytotoxic, for the same concentration. By contrast, TOTM and its corresponding metabolite MOTM were not found to be cytotoxic. DEHA showed no cytotoxicity, but its corresponding monoester (MEHA) produced a cytotoxic effect at 0.05 mg/ml. In clinical situations, medical devices can release plasticizers, which can come into contact with patients. In vivo, the plasticizers are quickly transformed into primary metabolites. It is therefore important to measure the effects of both the plasticizers and their corresponding metabolites. Standard first-line cytotoxicity assays should be performed to ensure biocompatibility.
- Eljezi, Teuta,Pinta, Pierre,Richard, Damien,Pinguet, Jérémy,Chezal, Jean-Michel,Chagnon, Marie-Christine,Sautou, Valérie,Grimandi, Ga?l,Moreau, Emmanuel
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p. 452 - 459
(2017/02/05)
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- Synthesis of monoesters and diesters using eco-friendly solid acid catalysts - Cerium(IV) and thorium(IV) phosphates
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In the present endeavour, amorphous cerium phosphate (CP) and thorium phosphate (TP) have been synthesized by sol-gel method and also under microwave irradiation to yield CPM and TPM. CP, TP, CPM and TPM have been characterized for elemental analysis (ICP-AES), spectral analysis (FTIR), thermal analysis (TGA), X-ray diffraction studies, SEM, EDX, surface area (BET) and surface acidity (NH3-TPD). The potential use of these materials as solid acid catalysts has been explored by studying esterification as a model reaction. Monoesters such as ethyl acetate (EA), propyl acetate (PA), butyl acetate (BA), benzyl acetate (BzAc) and diesters such as diethyl malonate (DEM), diethyl succinate (DES), dibutyl phthalate (DBP), dioctyl phthalate (DOP) have been synthesized. Esterification conditions have been optimized by varying several parameters such as reaction time, catalyst amount and mole ratio of reagents. The catalytic activity has been compared and correlated with reference to surface acidity of the catalysts. It is found that catalytic activity of CPM > CP > TP M > TP. The regenerated catalysts could be reused upto two catalytic runs without significant loss in % yields of esters formed. The highlighting feature of the present work is the catalysts CPM and TPM that are synthesized in a much shorter reaction time with higher surface acidity giving good % yield of esters.
- Parangi, Tarun,Wani, Bina,Chudasama, Uma
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p. 430 - 438
(2013/09/23)
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- Ecotoxicity and biodegradation of phthalate monoesters
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Little is known about the fate and the effects of phthalic acid monoesters. Various of these monoesters ranging from n-butyl to isononyl monoester have been evaluated in respect to their biodegradation behaviour and their acute aquatic toxicity. All esters are readily biodegradable, achieving degradation rates of 90% and more. The acute toxicity values strongly depend on the carbon chain length of the alcohol moiety. The short chain specimen have LC/EC 50 around and above 100 mg/l, with values levelling off to around 30 mg/l for the isononyl monoester.
- Scholz, Norbert
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p. 921 - 926
(2007/10/03)
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- Monitoring of phthalic acid monoesters in river water by solid-phase extraction and GC-MS determination
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An analytical method for monitoring 10 phthalic acid monoesters in river water was investigated by solid-phase extraction, methylation with diazomethane, and GC-MS. Two cartridge-type solid phases packed with octadesyl-coated silica (C18) and styrenedivinyl polymer (PS-2) and one disk-type solid phase made from octadesyl-coated styrene-divinylbenzene polymer (SDB-XD) were investigated in solid-phase extraction. PS-2 gave the highest recoveries of the three solid phases, and recoveries of more than 80% of the monoesters in filtered water samples were obtained at pH 2 to 3 with PS-2 at the spiked level of 0.1 μg L-1, except for monomethyl-phthalate (MMP), in which more than 72% of the monoesters were recovered. For the monoesters in the suspended solids (SS), an acidic methanol extract of SS was added to purified water acidified to pH 2, and the monoesters were extracted with PS-2. The recoveries of the monoesters in SS were more than 80%, but the recoveries of MMP were more than 57%. The method detection limit (MDL) of each phthalic acid monoester in 500 mL of water sample and in 2 mg of dry weight of SS ranged from 0.010 to 0.030 μg L-1 and from 1 to 11 μg g-1 respectively. Monitoring of phthalic acid monoesters in the Tama River in Tokyo was conducted every month from March 1999 to February 2000 using the present method. MMP, mono-n-butyl-phthalate (MBP), and mono-(2-ethylhexyl)-phthalate (MEHP) were detected at concentrations of 0.030-0.0340, 0.010-0.480, and 0.010-1.30 μg L-1. respectively, in the filtered water samples but were not detected in SS. Dimethyl-phthalate (DMP), di-n-butyl-phthalate (DBP), and di-(2-ethylhexyl)-phthalate (DEHP) were detected in the river water at concentrations of 0.010-0.092, 0.008-0.540, and 0.013-3.60 μg L-1, respectively. Diethyl-, di-iso-butyl-, and benzylbutyl-phthalates were also detected at concentrations of nanograms per liter, whereas the corresponding monoesters did not appear. The concentrations of MBP and MEHP in the river water were slightly lower than those of the corresponding diesters at the majority of sampling sites and sampling times.
- Suzuki,Yaguchi,Suzuki,Suga
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p. 3757 - 3763
(2007/10/03)
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- Treatment of skin conditions by use of PPAR alpha activators
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Disorders of the skin and mucous membrane that have a disrupted or dysfunctional epidermal barrier are treated or prevented by topical application of compounds that are either activators of the farnesoid X receptor, activators of the peroxisome proliferator-activated receptor alpha , and oxysterol activators of the LXR alpha receptor. The same compounds are also effective in treating disorders of epidermal differentiation and proliferation.
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- Involvement of a novel mouse hepatic microsomal esterase, ES46.5K, in the hydrolysis of phthalate esters
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ES46.5K, a novel esterase from mouse hepatic microsomes (Watanabe K., et al., Biochem. Mol. Biol. Int., 31, 25-30 (1993)), catalyzed hydrolysis of phthalate esters. ES46.5K and mouse hepatic microsomes hydrolyzed diethyl-, dibutyl-, diisobutyl-, dioctyl- and diethylhexyl phthalates, whereas dicyclohexyl- and dipbenyl phthalates having ring structure were not hydrolyzed by the enzymes. V(max) (μmol/min/mg protein)/K(m) (μM) ratios of ES46.5K for diethyl-, dibutyl-, diisobutyl-, dioctyl- and diethylhexyl phthalates were 291, 2786, 565, 51 and 57, respectively, while those of microsomes were 0.58, 0.83, 1.71, 0.05 and 1.10, respectively. The hydrolytic activity of ES46.5K was inhibited by diisopropylfluorophosphate and bis-p- nitrophenylphosphate. These results suggest that ES46.5K has high catalytic activity for phthalate esters and some role in the metabolism of phthalate esters in mice.
- Kayano, Yuichiro,Watanabe, Kazuhito,Matsunaga, Tamihide,Yamamoto, Ikuo,Yoshimura, Hidetoshi
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p. 749 - 751
(2007/10/03)
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- THE SIDE REACTIONS IN THE ESTERIFICATION OF PHTALIC ANHHYDRIDE WITH 2-ETHYLHEXANE-1-OL IN THE PRESENCE OF ORGANOTITANATES
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Using synthetic, chromatographic and spectral methods, we studied the side reactions accompanying the preparation of di-2-ethylhexyl phtalate from phtalic anhydride and 2-ethylhexane-1-ol in the presence of catalytic amounts of tetra-n-butyl titanate.The catalyst proper was titanium(IV) mono-2-ethylhexyl phtalate.The possibility of a simultaneous gas-chromatographic quantitative determination of mono-2-ethylhexyl phtalate, di-2-ethylhexyl phtalate, 2-ethylhexan-1-ol and tetra-n-butyl titanate, reported in literature, has been refuted.In the esterification catalysedby hydrated titanium dioxide homogeneous catalysis by the formed organotitanate was dominating.The dissolving of hydrated titanium dioxide in the esterification of phtalic anhydride with 2-ethylhexane-1-ol was studied polarographically.
- Novrocik, Jan,Novrocikova, Marta,Norek, Jiri,Koruna, Ivan,Ryska, Miroslav
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p. 253 - 266
(2007/10/02)
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