Search Within
Applied Filters:
Showing 1-30 of 31 results for "


" within Papers
Using high-performance quantitative NMR (HP-qNMR) for certifying traceable and highly accurate purity values of organic reference materials with uncertainties <0.1 %
Weber, M., Hellriegel, C., Rueck, A., Sauermoser, R., and Wuethrich, J.
Accreditation and Quality Assurance, 18, 91-98 (2013)
Xiao-Hui Duan et al.
The Journal of chemical physics, 120(21), 10025-10032 (2004-07-23)
Photoinduced electron transfer of the model system composed of vitamin E and duroquinone has been investigated using time-dependent density functional theory. Calculations for the excited states tell that the photoexcitation of the model system can directly yield the charge transfer
Andrea R Conlan et al.
Journal of molecular biology, 392(1), 143-153 (2009-07-08)
The endoplasmic reticulum protein Miner1 is essential for health and longevity. Mis-splicing of CISD2, which codes for Miner1, is causative in Wolfram Syndrome 2 (WFS2) resulting in early onset optic atrophy, diabetes mellitus, deafness and decreased lifespan. In knock-out studies
Michael Weber et al.
Journal of pharmaceutical and biomedical analysis, 93, 102-110 (2013-11-05)
Quantitative NMR spectroscopy (qNMR) is gaining interest across both analytical and industrial research applications and has become an essential tool for the content assignment and quantitative determination of impurities. The key benefits of using qNMR as measurement method for the
Michael Weber et al.
Analytical and bioanalytical chemistry, 407(11), 3115-3123 (2014-11-25)
Quantitative nuclear magnetic resonance (qNMR) spectroscopy is employed by an increasing number of analytical and industrial laboratories for the assignment of content and quantitative determination of impurities. Within the last few years, it was demonstrated that (1)H qNMR can be
Said H Audi et al.
American journal of physiology. Lung cellular and molecular physiology, 289(5), L788-L797 (2005-07-05)
NAD(P)H:quinone oxidoreductase 1 (NQO1) plays a dominant role in the reduction of the quinone compound 2,3,5,6-tetramethyl-1,4-benzoquinone (duroquinone, DQ) to durohydroquinone (DQH2) on passage through the rat lung. Exposure of adult rats to 85% O2 for > or =7 days stimulates
Structure and mechanism of cytosolic quinone reductases.
M A Bianchet et al.
Biochemical Society transactions, 27(4), 610-615 (2000-08-05)
Iu V Shatalin et al.
Biofizika, 53(1), 100-106 (2008-05-21)
The antioxidant activity of duroquinone and hypoxen was compared with that of alpha-tocopherol and vitamin C in a model system (luminol-peroxidase-H2O2), and their influence on the level of reactive oxygen species in systems containing polymorphonuclear leukocytes of healthy and tumor-bearing
J Maly et al.
Analytical and bioanalytical chemistry, 381(8), 1558-1567 (2005-04-12)
Mass transport of the bulk of the analyte to the electrode and through the bioactive layer can be significantly improved by use of the nanoelectrode array and defined arrangement of protein film. This phenomenon has been studied by (i) atomic-force
R A Rothery et al.
Biochemistry, 40(17), 5260-5268 (2001-04-25)
We have investigated the functional relationship between three of the prosthetic groups of Escherichia coli nitrate reductase A (NarGHI): the two hemes of the membrane anchor subunit (NarI) and the [3Fe-4S] cluster of the electron-transfer subunit (NarH). In two site-directed
Bingsheng Zhou et al.
Aquatic toxicology (Amsterdam, Netherlands), 77(2), 136-142 (2006-01-18)
Toxicity of many waterborne organic contaminants to aquatic organisms is mediated through oxidative damages resulting from the production of reactive oxygen species (ROS). Using duroquinone as a model ROS inducer, we carried out in vitro and in vivo experiments to
Chang Su Kim et al.
Molecules and cells, 17(2), 347-352 (2004-06-05)
We examined the damage to mitochondrial electron transport caused by photosensitization of a pheophorbide a derivative, DH-I-180-3, shown recently to induce necrosis of lung carcinoma cells with low dark toxicity. Confocal microscopy showed that DH-I-180-3 co-localized with dihydrorhodamine-123 suggesting that
Marilyn P Merker et al.
American journal of physiology. Lung cellular and molecular physiology, 290(3), L607-L619 (2005-10-26)
The objective of this study was to examine the impact of chronic hyperoxic exposure (95% O2 for 48 h) on intact bovine pulmonary arterial endothelial cell redox metabolism of 2,3,5,6-tetramethyl-1,4-benzoquinone (duroquinone, DQ). DQ or durohydroquinone (DQH2) was added to normoxic
Roger Giordani et al.
European journal of biochemistry, 271(12), 2400-2407 (2004-06-09)
In order to clarify the role of cytochrome in nitrate reductase we have performed spectrophotometric and stopped-flow kinetic studies of reduction and oxidation of the cytochrome hemes with analogues of physiological quinones, using menadione as an analogue of menaquinone and
Pavla Linhartova et al.
Toxicology in vitro : an international journal published in association with BIBRA, 27(6), 1612-1619 (2013-04-17)
The sturgeon is a highly endangered fish species mostly due to over-fishing, habitat destruction, and water pollution. Duroquinone (derivative of 1,4-benzoquinone) is a xenobiotic compound widespread in the environment. The effect of duroquinone on motility, DNA integrity, and oxidative stress
H L Reeve et al.
The Journal of physiology, 533(Pt 1), 253-261 (2001-05-15)
How the ductus arteriosus (DA) closes at birth remains unclear. Inhibition of O2-sensitive K+ channels may initiate the closure but the sensor mechanism is unknown. We hypothesized that changes in endogenous H2O2 could act as this sensor. Using chemiluminescence measurements
Brian J Lindemer et al.
American journal of physiology. Lung cellular and molecular physiology, 300(5), L773-L780 (2011-02-08)
The quinones duroquinone (DQ) and coenzyme Q(1) (CoQ(1)) and quinone reductase inhibitors have been used to identify reductases involved in quinone reduction on passage through the pulmonary circulation. In perfused rat lung, NAD(P)H:quinone oxidoreductase 1 (NQO1) was identified as the
Marilyn P Merker et al.
American journal of physiology. Lung cellular and molecular physiology, 293(3), L809-L819 (2007-07-03)
The objective was to determine the impact of intact normoxic and hyperoxia-exposed (95% O(2) for 48 h) bovine pulmonary arterial endothelial cells in culture on the redox status of the coenzyme Q(10) homolog coenzyme Q(1) (CoQ(1)). When CoQ(1) (50 microM)
Jean-Jacques Brière et al.
Biochemical and biophysical research communications, 316(4), 1138-1142 (2004-03-27)
Quinone derivatives are among the rare compounds successfully used as therapeutic reagents to fight mitochondrial diseases. However, their beneficial effect appears to depend on their side chain which presumably governs their interaction with the respiratory chain. The effect of four
Said H Audi et al.
American journal of physiology. Lung cellular and molecular physiology, 285(5), L1116-L1131 (2003-07-29)
The lungs can substantially influence the redox status of redox-active plasma constituents. Our objective was to examine aspects of the kinetics and mechanisms that determine pulmonary disposition of redox-active compounds during passage through the pulmonary circulation. Experiments were carried out
P Lagrange et al.
Free radical biology & medicine, 27(5-6), 667-672 (1999-09-18)
In the present study, we investigated the changes in blood-brain barrier (BBB) permeability following brain endothelial cell exposure to different xenobiotics able to promote free radical generation during their metabolism. Our in vitro BBB model consisted of confluent monolayers of
Xinkun Wang et al.
Genomics, 90(2), 201-212 (2007-06-08)
Neurons in the hippocampal CA1 region are particularly sensitive to oxidative stress (OS), whereas those in CA3 are resistant. To uncover mechanisms for selective CA1 vulnerability to OS, we treated organotypic hippocampal slices with duroquinone and compared transcriptional profiles of
Tadayuki Tsukatani et al.
Analytical sciences : the international journal of the Japan Society for Analytical Chemistry, 19(5), 659-664 (2003-05-29)
A method for the spectrophotometric assay of yeast vitality was developed using 2,3,5,6-tetramethyl-1,4-benzoquinone and tetrazolium salts. The metabolic efficiency of 2,3,5,6-tetramethyl-1,4-benzoquinone by yeast cells was used as an index of yeast vitality. 2,3,5,6-Tetramethyl-1,4-benzoquinone was reduced to 2,3,5,6-tetramethyl-1,4-hydroquinone by yeast cells.
Nikolai G Bukhov et al.
Biochimica et biophysica acta, 1604(2), 115-123 (2003-05-27)
Light modulation of the ability of three artificial quinones, 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB), 2,6-dichloro-p-benzoquinone (DCBQ), and tetramethyl-p-benzoquinone (duroquinone), to quench chlorophyll (Chl) fluorescence photochemically or non-photochemically was studied to simulate the functions of endogenous plastoquinones during the thermal phase of fast Chl
R H Bisby et al.
Free radical research, 35(1), 85-91 (2001-11-08)
Radicals from one-electron oxidation of 4-hydroxycinnamate, ferulate and 3,4-dihydroxycinnamate have been formed by reaction with the oxidising triplet state of duroquinone. All three compounds react with triplet duroquinone with second order rate constants close to the diffusion-controlled limit. The identity
Zhigang Zhou et al.
Biochemistry, 42(7), 1985-1994 (2003-02-20)
NAD(P)H/quinone acceptor oxidoreductase type 1 (QR1) protects cells from cytotoxic and neoplastic effects of quinones though two-electron reduction. Kinetic experiments, docking, and binding affinity calculations were performed on a series of structurally varied quinone substrates. A good correlation between calculated
Marilyn P Merker et al.
Free radical biology & medicine, 37(1), 86-103 (2004-06-09)
The study objective was to use pulmonary arterial endothelial cells to examine kinetics and mechanisms contributing to the disposition of the quinone 2,3,5,6-tetramethyl-1,4-benzoquinone (duroquinone, DQ) observed during passage through the pulmonary circulation. The approach was to add DQ, durohydroquinone (DQH2)
G J Wilde et al.
The European journal of neuroscience, 12(11), 3863-3870 (2000-11-09)
Upregulation of the pro-inflammatory cytokine tumour necrosis factor-alpha (TNF) occurs rapidly in the brain following ischaemia, although it is unclear whether this represents a neurotoxic or neuroprotective response. We have investigated whether TNF has different actions in the pre- and
R S Lemos et al.
FEBS letters, 496(1), 40-43 (2001-05-10)
Sulfate-reducing bacteria are considered as strict anaerobic microorganisms, in spite of the fact that some strains have been shown to tolerate the transient presence of dioxygen. This report shows that membranes from Desulfovibrio gigas grown in fumarate/sulfate contain a respiratory
Rui Xiong et al.
Toxicology and applied pharmacology, 280(2), 285-295 (2014-08-26)
Para-quinones such as 1,4-Benzoquinone (BQ) and menadione (MD) and ortho-quinones including the oxidation products of catecholamines, are derived from xenobiotics as well as endogenous molecules. The effects of quinones on major protein handling systems in cells; the 20/26S proteasome, the
Page 1 of 2
Page 1 of 2