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https://www.readbyqxmd.com/read/28723689/a-randomized-controlled-trial-of-green-tea-beverages-on-the-in-vivo-radical-scavenging-activity-in-human-skin
#1
Inna Megow, Maxim E Darvin, Martina C Meinke, Jürgen Lademann
BACKGROUND: Oxidative stress plays an important role in the pathogenesis of various skin diseases. Thus, the antioxidant network of the skin relies on the uptake of exogenous antioxidants to ensure cell protection against radical formation. Green tea is one of the main sources of polyphenolic antioxidant compounds, but only few data are available on its cutaneous antioxidant effects. METHODS: The radical scavenging properties of Benifuuki and Yabukita green tea were investigated in the human skin...
July 20, 2017: Skin Pharmacology and Physiology
https://www.readbyqxmd.com/read/28718469/characterization-of-the-thermal-thermal-oxidative-stability-of-fluorinated-graphene-with-various-structures
#2
Wenchuan Lai, Dazhou Xu, Xu Wang, Zaoming Wang, Yang Liu, Xiaojiao Zhang, Xiangyang Liu
Considering practical applications, the thermal/thermal oxidative stability of fluorinated graphene should be given sufficient attention. Herein, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR) were used to investigate in detail the differences in the thermal stabilities of two types of fluorinated samples, fluorinated graphene (FG) and fluorinated porous graphene (FPG) with various fluorine contents, respectively, as well as the reasons for these differences...
July 18, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28715227/balancing-passive-and-active-targeting-to-different-tumor-compartments-using-riboflavin-functionalized-polymeric-nanocarriers
#3
Yoanna Tsvetkova, Nataliia Beztsinna, Maike Baues, Dionne Klein, Anne Rix, Susanne Katherina Golombek, Wa'el Al Rawashdeh, Felix Gremse, Matthias Barz, Kaloian Koynov, Srinivas Banala, Wiltrud Lederle, Twan Lammers, Fabian Kiessling
Riboflavin Transporters (RFTs) and the Riboflavin Carrier Protein (RCP) are highly upregulated in many tumor cells, tumor stem cells and tumor neovasculature, which makes them attractive targets for nanomedicines. Addressing cells in different tumor compartments requires drug carriers, which are not only able to accumulate via the EPR effect, but also to extravasate, target specific cell populations, and get internalized by cells. Reasoning that antibodies are among the most efficient targeting systems developed by nature, we consider their size (~10-15 nm) to be ideal for balancing passive and active tumor targeting...
July 17, 2017: Nano Letters
https://www.readbyqxmd.com/read/28715188/understanding-microscopic-behavior-of-the-mixture-of-ionic-liquid-ethylene-glycol-lithium-salt-through-time-resolved-fluorescence-nuclear-magnetic-resonance-nmr-and-electron-paramagnetic-resonance-epr-studies
#4
Ranu Satish Dhale, Prabhat Kumar Sahu, Moloy Sarkar
The present study has been undertaken with an aim to find out the suitability of a binary solvent system, comprising an ionic liquid, 1-(2-Hydroxyethyl)-3-methylimidazolium bis (trifluoromethylsulfonyl)imide ([OHEMIM][NTf2]) and ethylene glycol (EG), towards lithium ion battery applications. For this purpose, the behavior in terms of structure, intermolecular interaction and dynamics of several solvent systems, [OHEMIM][NTf2], [OHEMIM][NTf2]-LiNTf2(lithium bis(trifluoromethylsulfonyl)imide), [OHEMIM][NTf2]-EG and [OHEMIM][NTf2]-EG-LiNTf2 are investigated by carrying out steady state and time-resolved fluorescence, nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) measurements...
July 17, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28715026/exchangeable-proton-endor-as-a-probe-of-the-redox-active-iron-center-in-activated-bleomycin-and-ferric-bleomycin
#5
Richard M Burger, Vladimir M Grigoryants, Charles P Scholes
Activated bleomycin (ABLM) is a drug-Fe(iii)-hydroperoxide complex kinetically competent in DNA attack (via H4' abstraction). This intermediate is relatively stable, but its spontaneous conversion to ferric bleomycin (Fe(iii)·BLM) is poorly characterized because no observable intermediate product accumulates. The Fe(iii)·BLM formed cryophotolytically from ABLM and kept at 77 K was remarkably similar by EPR and ENDOR criteria to Fe(iii)·BLM formed from Fe(iii) + BLM solution. The notable ENDOR criteria were the ENDOR frequencies and features of orientation-selected, strongly hyperfine-coupled, exchangeable protons associated with the environs of the iron within <3...
July 17, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28715016/synthesis-and-properties-of-a-series-of-%C3%AE-cyclodextrin-nitrone-spin-traps-for-improved-superoxide-detection
#6
Florent Poulhès, Egon Rizzato, Patrick Bernasconi, Roselyne Rosas, Stéphane Viel, Laszlo Jicsinszky, Antal Rockenbauer, David Bardelang, Didier Siri, Anouk Gaudel-Siri, Hakim Karoui, Micaël Hardy, Olivier Ouari
Three new DEPMPO-based spin traps have been designed and synthesized for improved superoxide detection, each carrying a cyclodextrin (CD) moiety but with a different alkyl chain on the phosphorus atom or with a long spacer arm. EPR spectroscopy allowed us to estimate the half-life of the superoxide spin adducts which is close to the value previously reported for CD-DEPMPO (t1/2 ≈ 50-55 min under the conditions investigated). The spectra are typical of superoxide adducts (almost no features of the HO˙ adduct that usually forms with time for other nitrone spin traps such as DMPO) and we show that at 250 μM, the new spin trap enables the reliable detection of superoxide by 1 scan at the position opposite to the corresponding spin trap without the CD moiety...
July 17, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28714679/spectroscopic-study-of-the-reversible-chemical-reduction-and-reoxidation-of-substitutional-cr-ions-in-sr2tio4
#7
Keith A Lehuta, Anubhab Haldar, Dongming Zhou, Kevin R Kittilstved
The solid-state synthesis and controllable speciation of Cr dopants in the layered perovskite Sr2TiO4 is reported. We employed a chemical reduction procedure with NaBH4 at relatively mild temperatures (<450 °C) to impart sensitive control over the relative concentration of Cr(3+) dopants, the charge-state of oxygen-vacancy defects, and presence of Ti(3+) defects in highly reduced Cr-doped Sr2TiO4. The electron paramagnetic resonance (EPR) spectra of the reduced powder samples reveal a 12-fold increase in the Cr(3+) concentration within the axially compressed Ti(4+)-site of the Sr2TiO4 host...
July 17, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28712810/conformational-heterogeneity-in-the-activation-mechanism-of-bax
#8
C Ashley Barnes, Pushpa Mishra, James L Baber, Marie-Paule Strub, Nico Tjandra
Bax is known for its pro-apoptotic role within the mitochondrial pathway of apoptosis. However, the mechanism for transitioning Bax from cytosolic to membrane-bound oligomer remains elusive. Previous nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) studies defined monomeric Bax as conformationally homogeneous. Yet it has recently been proposed that monomeric Bax exists in equilibrium with a minor state that is distinctly different from its NMR structure. Here, we revisited the structural analysis of Bax using methods uniquely suited for unveiling "invisible" states of proteins, namely, NMR paramagnetic relaxation enhancements and EPR double electron-electron resonance (DEER)...
July 3, 2017: Structure
https://www.readbyqxmd.com/read/28712303/mn-ii-oxidation-by-the-multicopper-oxidase-complex-mnx-a-coordinated-two-stage-mn-ii-iii-and-mn-iii-iv-mechanism
#9
Alexandra V Soldatova, Christine A Romano, Lizhi Tao, Troy A Stich, William H Casey, R David Britt, Bradley M Tebo, Thomas G Spiro
The bacterial manganese oxidase MnxG of the Mnx protein complex is unique among multicopper oxidases (MCOs) in carrying out a two-electron metal oxidation, converting Mn(II) to MnO2 nanoparticles. The reaction occurs in two stages: Mn(II)→Mn(III) and Mn(III)→MnO2. In a companion study,(1) we show that the electron transfer from Mn(II) to the low-potential type 1 Cu of MnxG requires an activation step, likely forming a hydroxide bridge at a dinuclear Mn(II) site. Here we study the second oxidation step, using pyrophosphate (PP) as a Mn(III) trap...
July 17, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28706754/smart-release-nano-formulation-of-cytochrome-c-and-hyaluronic-acid-induces-apoptosis-in-cancer-cells
#10
C M Figueroa, B N Suárez, A M Molina, J C Fernández, Z Torres, K Griebenow
Herein we tested a nanosized cancer-cell targeted delivery system based on cytochrome c (Cyt c) and hyaluronic acid. Cyt c was chosen since it is a per se non-toxic protein but causes apoptosis when delivered to the cytoplasm of target cells. Hyaluronic acid was employed to create the nanosized delivery system with passive targeting capability in order to exploit the enhanced permeation and retention (EPR) effect and active targeting capability of hyaluronic acid. In addition, our goal was to incorporate a smart release strategy to only promote protein release upon reaching its target...
February 2017: Journal of Nanomedicine & Nanotechnology
https://www.readbyqxmd.com/read/28702582/recognition-of-phosphopeptides-by-a-dinuclear-copper-ii-macrocyclic-complex-in-a-water%C3%A2-%C3%A2-methanol-50%C3%A2-%C3%A2-50-v-v-solution
#11
Lígia M Mesquita, Pedro Mateus, Rui D V Fernandes, Olga Iranzo, Vânia André, Filipe Tiago de Oliveira, Carlos Platas-Iglesias, Rita Delgado
A new triethylbenzene-derived tetraazamacrocycle containing pyridyl spacers, L, was prepared and its dinuclear copper(ii) complex was used as a receptor for the recognition of phosphorylated peptides in aqueous solution. A detailed study of the acid-base behaviour of L and its copper(ii) complexation properties as well as of the cascade species with phosphorylated anions including two peptidic substrates was carried out in a H2O/MeOH (50 : 50 v/v) solution using different techniques, such as potentiometry, X-band EPR and DFT calculations...
July 12, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28701427/controlling-phlebotomy-volume-diminishes-picu-transfusion-implementation-processes-and-impact
#12
Katherine Steffen, Allan Doctor, Julie Hoerr, Jeff Gill, Chris Markham, Sarah M Brown, Daniel Cohen, Rose Hansen, Emily Kryzer, Jessica Richards, Sara Small, Stacey Valentine, Jennifer L York, Enola K Proctor, Philip C Spinella
BACKGROUND AND OBJECTIVES: Phlebotomy excess contributes to anemia in PICU patients and increases the likelihood of red blood cell transfusion, which is associated with risk of adverse outcomes. Excessive phlebotomy reduction (EPR) strategies may reduce the need for transfusion, but have not been evaluated in a PICU population. We hypothesized that EPR strategies, facilitated by implementation science methods, would decrease excess blood drawn and reduce transfusion frequency. METHODS: Quantitative and qualitative methods were used...
July 13, 2017: Pediatrics
https://www.readbyqxmd.com/read/28697952/pharmacological-and-physical-vessel-modulation-strategies-to-improve-epr-mediated-drug-targeting-to-tumors
#13
Tarun Ojha, Vertika Pathak, Yang Shi, Wim Hennink, Chrit Moonen, Gert Storm, Fabian Kiessling, Twan Lammers
The performance of nanomedicine formulations depends on the Enhanced Permeability and Retention (EPR) effect. Prototypic nanomedicine-based drug delivery systems, such as liposomes, polymers and micelles, aim to exploit the EPR effect to accumulate at pathological sites, to thereby improve the balance between drug efficacy and toxicity. Thus far, however, tumor-targeted nanomedicines have not yet managed to achieve convincing therapeutic results, at least not in large cohorts of patients. This is likely mostly due to high inter- and intra-patient heterogeneity in EPR...
July 8, 2017: Advanced Drug Delivery Reviews
https://www.readbyqxmd.com/read/28696461/room-temperature-in-cell-epr-spectroscopy-alpha-synuclein-disease-variants-remain-intrinsically-disordered-in-the-cell
#14
Julia Cattani, Vinod Subramaniam, Malte Drescher
Human alpha-Synuclein (aS), implicated in Parkinson's disease, adopts a rich variety of different conformations depending on the macromolecular context. In order to unravel its pathophysiological role, monitoring its intracellular conformational state and identifying differences for the disease variants is crucial. Here, we present an intracellular spectroscopy approach based on a systematic spin-labeling site-scan in combination with intracellular electron paramagnetic resonance spectroscopy determining conformations on a molecular scale...
July 11, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28693028/desgarros-del-epitelio-pigmentario-de-la-retina-factores-de-riesgo-mecanismo-y-control-terap%C3%A3-utico
#15
Christoph R Clemens, Nicole Eter
Los desgarros del epitelio pigmentario de la retina (EPR) se asocian en la mayoría de los casos con los desprendimientos vascularizados del EPR debido a una degeneración macular asociada a la edad (DMAE), y normalmente implican una pérdida adversa de la agudeza visual. Estudios recientes indican que ha habido un aumento en la incidencia de desgarros del EPR desde la introducción de fármacos anti-factor de crecimiento del endotelio vascular (anti-VEGF) así como una asociación temporal entre el desgarro y la inyección intravítrea...
July 11, 2017: Ophthalmologica. Journal International D'ophtalmologie
https://www.readbyqxmd.com/read/28692887/electron-magnetic-resonance-data-on-high-spin-mn-iii-s-2-ions-in-porphyrinic-and-salen-complexes-modeled-by-microscopic-spin-hamiltonian-approach
#16
Krzysztof Tadyszak, Czesław Rudowicz, Hitoshi Ohta, Takahiro Sakurai
The spin Hamiltonian (SH) parameters experimentally determined by EMR (EPR) may be corroborated or otherwise using various theoretical modeling approaches. To this end semiempirical modeling is carried out for high-spin (S=2) manganese (III) 3d(4) ions in complex of tetraphenylporphyrinato manganese (III) chloride (MnTPPCl). This modeling utilizes the microscopic spin Hamiltonians (MSH) approach developed for the 3d(4) and 3d(6) ions with spin S=2 at orthorhombic and tetragonal symmetry sites in crystals, which exhibit an orbital singlet ground state...
June 28, 2017: Journal of Inorganic Biochemistry
https://www.readbyqxmd.com/read/28692802/reversible-protonated-resting-state-of-the-nitrogenase-active-site
#17
Christine N Morrison, Thomas Spatzal, Douglas C Rees
Protonated states of the nitrogenase active site are mechanistically significant since substrate reduction is invariably accompanied by proton uptake. We report the low pH characterization by X-ray crystallography and EPR spectroscopy of the nitrogenase molybdenum iron (MoFe) proteins from two phylogenetically distinct nitrogenases (Azotobacter vinelandii, Av, and Clostridium pasteurianum, Cp) at pHs between 4.5 to 8. X-ray data at pHs of 4.5 - 6 reveal the repositioning of sidechains along one side of the FeMo-cofactor, and the corresponding EPR data shows a new S = 3/2 spin system with spectral features similar to a state previously observed during catalytic turnover...
July 10, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28691114/structure-and-dynamics-of-type-iii-secretion-effector-protein-exou-as-determined-by-sdsl-epr-spectroscopy-in-conjunction-with-de-novo-protein-folding
#18
Axel W Fischer, David M Anderson, Maxx H Tessmer, Dara W Frank, Jimmy B Feix, Jens Meiler
ExoU is a 74 kDa cytotoxin that undergoes substantial conformational changes as part of its function, that is, it has multiple thermodynamically stable conformations that interchange depending on its environment. Such flexible proteins pose unique challenges to structural biology: (1) not only is it often difficult to determine structures by X-ray crystallography for all biologically relevant conformations because of the flat energy landscape (2) but also experimental conditions can easily perturb the biologically relevant conformation...
June 30, 2017: ACS Omega
https://www.readbyqxmd.com/read/28689402/purple-fibrils-a-new-type-of-protein-chromophore
#19
Tatiana Quiñones-Ruiz, Manuel F Rosario-Alomar, Karina Ruiz-Esteves, Maruda Shanmugasundaram, Vladimir Grigoryants, Charles Scholes, Juan López-Garriga, Igor K Lednev
A purple color is formed during the fibrillation of lysozyme, a well-studied protein lacking a prosthetic group. The application of Raman spectroscopy, electron paramagnetic resonance and UV-vis absorption spectroscopy indicates the formation of a sulfur∴π-bonded radical cation due to the methionine-phenylalanine interaction, which is consistent with a small molecule model reported in the literature. A purple chromophore with characteristic 550 nm absorption is formed due to a specific orientation of the sulfur-centered radical cation and a phenyl ring stabilized by the fibril framework...
July 12, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28688365/albumin-nanoparticles-with-synergistic-antitumor-efficacy-against-metastatic-lung-cancers
#20
Bomi Kim, Bohyung Seo, Sanghyun Park, Changkyu Lee, Jong Oh Kim, Kyung Taek Oh, Eun Seong Lee, Han-Gon Choi, Yu Seok Youn
Albumin nanoparticles are well-known as effective drug carriers used to deliver hydrophobic chemotherapeutic agents. Albumin nanoparticles encapsulating curcumin and doxorubicin were fabricated using slightly modified nanoparticle albumin-bound (nab™) technology, and the synergistic effects of these two drugs were examined. Albumin nanoparticles encapsulating curcumin, doxorubicin, and both curcumin and doxorubicin were prepared using a high pressure homogenizer. The sizes of albumin nanoparticles were ∼130nm, which was considered to be suitable for the EPR (enhanced permeability and retention) effect...
June 27, 2017: Colloids and Surfaces. B, Biointerfaces
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