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https://www.readbyqxmd.com/read/27913846/potent-mutagenicity-of-some-non-planar-tri-and-tetrachlorinated-biphenyls-in-mammalian-cells-human-cyp2e1-being-a-major-activating-enzyme
#1
Yungang Liu, Keqi Hu, Hansi Jia, Guifang Jin, Hansruedi Glatt, Hao Jiang
Polychlorinated biphenyls (PCBs) have been classified as human carcinogens. Mutagenicity of lower chlorinated biphenyls as well as activation of transcription factors by some other congeners may contribute to the carcinogenicity of PCBs. Recently, we reported that human CYP2E1 activates mono- and dichlorobiphenyls to mutagens. However, mutagenicity of other PCBs and the involvement of other CYPs remained unknown. In this study, Chinese hamster V79-derived cell lines genetically engineered for expression of individual human CYP enzymes and a human hepatocyte (L-02) line endogenously expressing various CYPs were used to determine the activities of several tri- and tetrachlorobiphenyls to induce micronuclei and gene mutations...
December 2, 2016: Archives of Toxicology
https://www.readbyqxmd.com/read/27872784/ciprofloxacin-and-clozapine-a-potentially-fatal-but-underappreciated-interaction
#2
Jonathan M Meyer, George Proctor, Michael A Cummings, Laura J Dardashti, Stephen M Stahl
Objective. Clozapine provides a 50%-60% response rate in refractory schizophrenia but has a narrow therapeutic index and is susceptible to pharmacokinetic interactions, particularly with strong inhibitors or inducers of cytochrome P450 (CYP) 1A2. Case Report. We report the case of a 28-year-old nonsmoking female with intellectual disability who was maintained for 3 years on clozapine 100 mg orally twice daily. The patient was treated for presumptive urinary tract infection with ciprofloxacin 500 mg orally twice daily and two days later collapsed and died despite resuscitation efforts...
2016: Case Reports in Psychiatry
https://www.readbyqxmd.com/read/27872699/the-effects-of-fenvalerate-on-hepatic-and-cerebral-xenobiotic-metabolizing-enzymes-in-selenium-and-or-iodine-deficient-rats
#3
Aydan Caglayan, Belma Kocer-Gumusel, Pinar Erkekoglu, Filiz Hincal
OBJECTIVES: Particularly in developing countries, selenium and/or iodine deficiencies are encountered and use of pesticides in agriculture are not well-controlled. Fenvalerate is a pyrethroid insectide used in agriculture and has applications against a wide range of pests. This study was designed to evaluate the effects of fenvalerate on hepatic and cerebral xenobiotic metabolizing enzyme activities in the presence of iodine and/or selenium deficiency on a rat model. MATERIALS AND METHODS: Iodine and/or selenium deficiency was induced by feeding three-week-old Wistar rats with a diet containing <0...
October 2016: Iranian Journal of Basic Medical Sciences
https://www.readbyqxmd.com/read/27842484/strong-induction-of-cytochrome-p450-1a-3a-but-not-p450-2b-in-cultured-hepatocytes-from-common-marmosets-and-cynomolgus-monkeys-by-typical-human-p450-inducing-agents
#4
Shotaro Uehara, Yasuhiro Uno, Takako Suzuki, Takashi Inoue, Masahiro Utoh, Erika Sasaki, Hiroshi Yamazaki
BACKGROUND: Common marmosets (Callithrix jacchus) and cynomolgus monkeys (Macaca fascicularis) are used as non-human primate models in preclinical studies for drug development. OBJECTIVE: The assessment of P450 induction in hepatocytes from marmosets and cynomolgus monkeys was performed using typical P450 inducers. METHODS: Induction of cytochrome P450 1-4 family enzymes was analyzed in two lots of cultured hepatocytes from common marmosets and cynomolgus monkeys after 24-h treatment with typical human P450 inducing agents by real-time reverse transcription-polymerase chain reaction...
November 14, 2016: Drug Metabolism Letters
https://www.readbyqxmd.com/read/27819189/inhibitory-effects-of-curculigoside-on-human-liver-cytochrome-p450-enzymes
#5
Jixiao Lang, Wei Li, Jingming Zhao, Kaiyou Wang, Dexi Chen
1. Curculigoside possesses numerous pharmacological activities, and however, little data available for the effects of curculigoside on the activity of human liver cytochrome P450 (CYP) enzymes. 2. This study investigates the inhibitory effects of curculigoside on the main human liver CYP isoforms. In this study, the inhibitory effects of curculigoside on the eight human liver CYP isoforms 1A2, 2A6, 2E1, 2D6, 2C9, 2C19, 2C8, and 3A4 were investigated in human liver microsomes. 3. The results indicated that curculigoside could inhibit the activity of CYP1A2, CYP2C8, and CYP3A4, with IC50 values of 15...
November 5, 2016: Xenobiotica; the Fate of Foreign Compounds in Biological Systems
https://www.readbyqxmd.com/read/27799384/severe-asthma-exists-despite-suppressed-tissue-inflammation-findings-of-the-u-biopred-study
#6
Susan J Wilson, Jonathan A Ward, Ana R Sousa, Julie Corfield, Aruna T Bansal, Bertrand De Meulder, Diane Lefaudeux, Charles Auffray, Matthew J Loza, Frederic Baribaud, Neil Fitch, Peter J Sterk, Kian Fan Chung, David Gibeon, Kai Sun, Yi-Ke Guo, Ian Adcock, Ratko Djukanovic, Barbro Dahlen, Pascal Chanez, Dominick Shaw, Norbert Krug, Jens Hohlfeld, Thomas Sandström, Peter H Howarth
The U-BIOPRED study is a multicentre European study aimed at a better understanding of severe asthma. It included three steroid-treated adult asthma groups (severe nonsmokers (SAn group), severe current/ex-smokers (SAs/ex group) and those with mild-moderate disease (MMA group)) and healthy controls (HC group). The aim of this cross-sectional, bronchoscopy substudy was to compare bronchial immunopathology between these groups.In 158 participants, bronchial biopsies and bronchial epithelial brushings were collected for immunopathologic and transcriptomic analysis...
November 2016: European Respiratory Journal: Official Journal of the European Society for Clinical Respiratory Physiology
https://www.readbyqxmd.com/read/27783977/targeting-the-entry-region-of-hsp90-s-atp-binding-pocket-with-a-novel-6-7-dihydrothieno-3-2-c-pyridin-5-4h-yl-amide
#7
Ju Hui Jeong, Yong Jin Oh, Yunmee Lho, Sun You Park, Kwang-Hyeon Liu, Eunyoung Ha, Young Ho Seo
The molecular chaperone Hsp90 plays an important role in cancer cell survival and proliferation by regulating the maturation and stabilization of numerous oncogenic proteins. Due to its potential to simultaneously disable multiple signaling pathways, Hsp90 has emerged as an attractive therapeutic target for cancer treatment. In this study, the design, synthesis, and biological evaluation of a series of Hsp90 inhibitors are described. Among the synthetic compounds, 6,7-dihydrothieno [3,2-c]pyridin-5(4H)-yl amide 19 exhibits a remarkable binding affinity to the N-terminus of Hsp90 in a fluorescence polarization (FP) binding assay (IC50 = 50...
October 18, 2016: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/27783651/collagen-xii-contributes-to-epicardial-and-connective-tissues-in-the-zebrafish-heart-during-ontogenesis-and-regeneration
#8
Jan Marro, Catherine Pfefferli, Anne-Sophie de Preux Charles, Thomas Bise, Anna Jaźwińska
Zebrafish heart regeneration depends on cardiac cell proliferation, epicardium activation and transient reparative tissue deposition. The contribution and the regulation of specific collagen types during the regenerative process, however, remain poorly characterized. Here, we identified that the non-fibrillar type XII collagen, which serves as a matrix-bridging component, is expressed in the epicardium of the zebrafish heart, and is boosted after cryoinjury-induced ventricular damage. During heart regeneration, an intense deposition of Collagen XII covers the outer epicardial cap and the interstitial reparative tissue...
2016: PloS One
https://www.readbyqxmd.com/read/27783531/the-role-of-organic-anion-transporting-polypeptides-in-drug-absorption-distribution-excretion-and-drug-drug-interactions
#9
Daniella Kovacsics, Izabel Patik, Csilla Özvegy-Laczka
The in vivo fate and effectiveness of a drug depends highly on its absorption, distribution, metabolism, excretion and toxicity (ADME-Tox). Organic anion transporting polypeptides (OATPs) are membrane proteins involved in the cellular uptake of various organic compounds, including clinically used drugs. Since OATPs are significant players in drug absorption and distribution, modulation of OATP function via pharmacotherapy with OATP substrates/inhibitors, or modulation of their expression, affects drug pharmacokinetics...
October 26, 2016: Expert Opinion on Drug Metabolism & Toxicology
https://www.readbyqxmd.com/read/27783139/lack-of-effect-of-smoking-status-on-axitinib-pharmacokinetics-in-patients-with-non-small-cell-lung-cancer
#10
May Garrett, Timothy Taylor, Diane R Mould, Michael A Amantea, Ying Chen, Antonella Ingrosso, Yazdi K Pithavala
PURPOSE: Axitinib, a tyrosine kinase inhibitor targeting vascular endothelial growth factor receptors 1-3, is approved for second-line treatment of advanced renal cell carcinoma. Axitinib is partially metabolized by cytochrome P450 1A2, which is induced by chronic heavy smoking. The effect of smoking on axitinib pharmacokinetics was evaluated in a non-small-cell lung cancer (NSCLC) patient population with a large number of active and ex-smokers. METHODS: Data were pooled from six clinical studies-serial pharmacokinetics from two healthy volunteer studies (n = 58) and sparse pharmacokinetics from four NSCLC studies (n = 152)-for a nonlinear mixed effects modeling (NONMEM v7...
October 25, 2016: Cancer Chemotherapy and Pharmacology
https://www.readbyqxmd.com/read/27722524/lipid-molecules-can-induce-an-opening-of-membrane-facing-tunnels-in-cytochrome-p450-1a2
#11
Petr Jeřábek, Jan Florián, Václav Martínek
Cytochrome P450 1A2 (P450 1A2, CYP1A2) is a membrane-bound enzyme that oxidizes a broad range of hydrophobic substrates. The structure and dynamics of both the catalytic and trans-membrane (TM) domains of this enzyme in the membrane/water environment were investigated using a multiscale computational approach, including coarse-grained and all-atom molecular dynamics. Starting from the spontaneous self-assembly of the system containing the TM or soluble domain immersed in randomized dilauroyl phosphatidylcholine (DLPC)/water mixture into their respective membrane-bound forms, we reconstituted the membrane-bound structure of the full-length P450 1A2...
November 9, 2016: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27721546/metabolism-mediated-interaction-potential-of-standardized-extract-of-tinospora-cordifolia-through-rat-and-human-liver-microsomes
#12
Shiv Bahadur, Pulok K Mukherjee, S K Milan Ahmmed, Amit Kar, Ranjit K Harwansh, Subrata Pandit
OBJECTIVE: Tinospora cordifolia is used for treatment of several diseases in Indian system of medicine. In the present study, the inhibition potential of T. cordifolia extracts and its constituent tinosporaside to cause herb-drug interactions through rat and human liver cytochrome enzymes was evaluated. MATERIALS AND METHODS: Bioactive compound was quantified through reverse phase high-performance liquid chromatography, to standardize the plant extracts and interaction potential of standardized extract...
September 2016: Indian Journal of Pharmacology
https://www.readbyqxmd.com/read/27713762/assessment-of-cyp1a2-enzyme-activity-in-relation-to-type-2-diabetes-and-habitual-caffeine-intake
#13
Emily Urry, Alexander Jetter, Hans-Peter Landolt
BACKGROUND: Coffee consumption is a known inducer of cytochrome P450 1A2 (CYP1A2) enzyme activity. We recently observed that a group of type-2 diabetes patients consumed more caffeine (coffee) on a daily basis than non-type-2 diabetes controls. Here, we investigated whether type-2 diabetes cases may metabolize caffeine faster than non-type-2 diabetes controls. METHODS: To estimate CYP1A2 enzyme activity, an established marker of caffeine metabolism, we quantified the paraxanthine/caffeine concentration ratio in saliva in 57 type-2 diabetes and 146 non-type-2 diabetes participants in a case-control field study...
2016: Nutrition & Metabolism
https://www.readbyqxmd.com/read/27644595/aryl-hydrocarbon-receptor-activation-and-cyp1a-induction-by-cooked-food-derived-carcinogenic-heterocyclic-amines-in-human-hepg2-cell-lines
#14
Masashi Sekimoto, Haruna Sumi, Takuomi Hosaka, Takashi Umemura, Akiyoshi Nishikawa, Masakuni Degawa
The ability of nine cooked food-derived heterocyclic aromatic amines (HCAs), such as 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), 2-amino-6-methylpyrido[12-a:3',2'-d]imidazole (Glu-P-1), 2-amino-pyrido[12-a:3',2'-d]imidazole hydrochloride (Glu-P-2), 2-amino-9H-pyrido[2,3-b]indole (AαC), 2-amino-3-methyl-9H-pyrido[2,3-b]indole (MeAαC), 2-amino-3-methylimidazo[4,5-f]quinolone (IQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-1-methyl-6-phenyl-1H-imidazo[4,5-b]pyridine (PhIP), to activate human aryl hydrocarbon receptor (hAhR) was examined using a HepG2-A10 cell line, which has previously established from human hepatocarcinoma-derived HepG2 cells for use in hAhR-based luciferase reporter gene assays...
September 16, 2016: Food and Chemical Toxicology
https://www.readbyqxmd.com/read/27637481/a-comparison-of-the-genotoxicity-of-benzo-a-pyrene-in-four-cell-lines-with-differing-metabolic-capacity
#15
Ume-Kulsoom Shah, Anna L Seager, Paul Fowler, Shareen H Doak, George E Johnson, Sharon J Scott, Andrew D Scott, Gareth J S Jenkins
Benzo[a]pyrene (B[a]P) is a known genotoxin and carcinogen, yet its genotoxic response at low level exposure has not been determined. This study was conducted to examine the interplay of dose and metabolic capacity on genotoxicity of B[a]P. Investigating and better understanding the biological significance of low level chemical exposures will help improve human health risk assessments. The genotoxic and mutagenic effects of B[a]P were investigated using human cell lines (AHH-1, MCL-5, TK6 and HepG2) with differential expression of the CYP450 enzymes CYP1A1, 1B1 and1A2 involved in B[a]P metabolism...
September 15, 2016: Mutation Research. Genetic Toxicology and Environmental Mutagenesis
https://www.readbyqxmd.com/read/27633141/the-natural-anthraquinones-from-rheum-palmatum-induced-the-metabolic-disorder-of-melatonin-by-inhibiting-human-cyp-and-sult-enzymes
#16
Weiru Jiang, Xiangge Tian, Yan Wang, Zheng Sun, Peipei Dong, Chao Wang, Xiaokui Huo, Baojing Zhang, Shanshan Huang, Sa Deng, Xiaobo Wang, Xiaochi Ma
Melatonin (Mel) as an endogenous hormone, has been widely used in clinic for multiple therapeutic purposes. Further, the natural anthraquinones were widespread in various plants including herbs, foods, and some flavoring agents. The present work aims to evaluate the metabolic disorder of Mel caused by various common herbs and further identify their underlying mechanism. More importantly, the relationships between inhibitory activity and their structures were also investigated. Our results demonstrate that some herbs containing anthraquinone derivatives exhibited strong inhibition on Mel metabolism...
September 12, 2016: Toxicology Letters
https://www.readbyqxmd.com/read/27630718/induction-of-tenogenic-differentiation-mediated-by-extracellular-tendon-matrix-and-short-term-cyclic-stretching
#17
Janina Burk, Amelie Plenge, Walter Brehm, Sandra Heller, Bastian Pfeiffer, Cornelia Kasper
Tendon and ligament pathologies are still a therapeutic challenge, due to the difficulty in restoring the complex extracellular matrix architecture and biomechanical strength. While progress is being made in cell-based therapies and tissue engineering approaches, comprehensive understanding of the fate of progenitor cells in tendon healing is still lacking. The aim of this study was to investigate the effect of decellularized tendon matrix and moderate cyclic stretching as natural stimuli which could potentially direct tenogenic fate...
2016: Stem Cells International
https://www.readbyqxmd.com/read/27625140/roles-of-human-cyp2a6-and-monkey-cyp2a24-and-2a26-cytochrome-p450-enzymes-in-the-oxidation-of-2-5-2-5-tetrachlorobiphenyl
#18
Tsutomu Shimada, Kensaku Kakimoto, Shigeo Takenaka, Nobuyuki Koga, Shotaro Uehara, Norie Murayama, Hiroshi Yamazaki, Donghak Kim, Frederick Peter Guengerich, Masayuki Komori
2,5,2',5'-Tetrachlorobiphenyl (TCB) induced Type I binding spectra with cytochrome P450 (P450 or CYP) 2A6 and 2A13, having Ks values of 9.4 and 0.51 μM, respectively. However, CYP2A6 oxidized 2,5,2',5'-TCB to form 4-hydroxylated products at a much higher rate (~1.0 min-1) than CYP2A13 (~0.02 min-1), based on analysis by LC-MS/MS. Formation of 4-hydroxy-2,5,2',5'-TCB by CYP2A6 was greater than that of 3-hydroxy-2,5,2',5'-TCB and three other hydroxylated products. Several human P450 enzymes, including CYP1A1, 1A2, 1B1, 2B6, 2D6, 2E1, 2C9, and 3A4, did not show any detectable activities in oxidizing 2,5,2',5'-TCB...
September 13, 2016: Drug Metabolism and Disposition: the Biological Fate of Chemicals
https://www.readbyqxmd.com/read/27621621/the-effect-of-zno-nanoparticles-on-liver-function-in-rats
#19
Hua-Qiao Tang, Min Xu, Qian Rong, Ru-Wen Jin, Qi-Ji Liu, Ying-Lun Li
Zinc oxide (ZnO) is widely incorporated as a food additive in animal diets. In order to optimize the beneficial effects of ZnO and minimize any resultant environmental pollution, ZnO nanoparticles are often used for delivery of the zinc. However, the possible toxic effects of ZnO nanoparticles, including effects on cytochrome P450 (CYP450) enzymes, have not been evaluated. In this study, we investigated the effect of ZnO nanoparticles, in doses used in animal feeds, on CYP450 enzymes, liver and intestinal enzymes, liver and kidney histopathology, and hematologic indices in rats...
2016: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/27604104/strain-differences-in-the-proteome-of-dioxin-sensitive-and-dioxin-resistant-mice-treated-with-2-3-7-8-tetrabromodibenzo-p-dioxin
#20
Hoa Thanh Nguyen, Maria Claret Lauan Tsuchiya, Jean Yoo, Midori Iida, Tetsuro Agusa, Masashi Hirano, Eun-Young Kim, Tatsuhiko Miyazaki, Masato Nose, Hisato Iwata
Dioxins cause various toxic effects through the aryl hydrocarbon receptor (AHR) in vertebrates, with dramatic species and strain differences in susceptibility. Although inbred mouse strains C3H/HeJ-lpr/lpr (C3H/lpr) and MRL/MpJ-lpr/lpr (MRL/lpr) are known as dioxin-sensitive and dioxin-resistant mice, respectively, the molecular mechanism underlying this difference remains unclear. The difference in the hepatic proteome of the two mouse strains treated with vehicle or 2,3,7,8-tetrabromodibenzo-p-dioxin (TBDD) was investigated by a proteomic approach of two-dimensional electrophoresis (2-DE) coupled with matrix-assisted laser desorption/ionization time-of-flight/time-of-flight tandem mass spectrometry (MALDI-TOF/TOF)...
September 7, 2016: Archives of Toxicology
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