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https://www.readbyqxmd.com/read/28532094/electrochemical-sensing-of-doxorubicin-in-unprocessed-whole-blood-cell-lysate-and-human-plasma-samples-using-thin-film-of-poly-arginine-modified-glassy-carbon-electrode
#1
Jafar Soleymani, Mohammad Hasanzadeh, Morteza Eskandani, Maryam Khoubnasabjafari, Nasrin Shadjou, Abolghasem Jouyban
A thin film of poly-arginine fabricated on glassy carbon electrode by one step electrodeposition method is applied for detection of doxorubicin hydrochloride in whole blood, cell lysate, and untreated-plasma samples. Cyclic voltammetry results indicated that the doxorubicin is oxidized via two electrons and two protons at physiological pH (pH=7.4) using poly-arginine thin film modified glassy carbon. More importantly, electrostatic repulsion takes place between the prepared polymer film-modified electrode and selected drug resulting in the signal amplification on oxidation of doxorubicin and lowering its over potential and thereby selective detection of doxorubicin in real samples...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28531794/binding-of-the-anticancer-drug-bi-2536-to-human-serum-albumin-a-spectroscopic-and-theoretical-study
#2
Jesús Fernández-Sainz, Pedro J Pacheco-Liñán, José M Granadino-Roldán, Iván Bravo, Andrés Garzón, Jaime Rubio-Martínez, José Albaladejo
BI-2536 is a potent Polo-like kinase inhibitor which induces apoptosis in diverse human cancer cell lines. The binding affinity of BI-2536 for human serum albumin (HSA) protein may define its pharmacokinetic and pharmacodynamic profile. We have studied the binding of BI-2536 to HSA by means of different spectroscopic techniques and docking calculations. We have experimentally observed that the affinity of BI-2536 for HSA is higher than that of other common HSA binding drugs. Therefore, it can be postulated that the drug dose should be increased to achieve a certain concentration of free drug in plasma, although BI-2536 could also reach tumour tissues by uptaking HSA/BI-2536 complex...
May 12, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28531352/conformational-complexity-in-the-lh2-antenna-of-the-purple-sulfur-bacterium-allochromatium-vinosum-revealed-by-hole-burning-spectroscopy
#3
Adam Kell, Mahboobe Jassas, Khem Acharya, Kirsty Hacking, Richard J Cogdell, Ryszard J Jankowiak
This work discusses the protein conformational complexity of the B800-850 LH2 complexes from the purple sulfur bacterium Allochromatium vinosum, focusing on the spectral characteristics of the B850 chromophores. Low-temperature B850 absorption and the split B800 band shift blue and red, respectively, at elevated temperatures, revealing isosbestic points. The latter indicates the presence of two (unresolved) conformations of B850 bacteriochlorophylls (BChls), referred to as conformations 1 and 2, and two conformations of B800 BChls, denoted as B800R and B800B...
May 22, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28531106/fully-polymeric-ph-sensor-realized-by-means-of-a-single-step-soft-embossing-technique
#4
Paola Fanzio, Chi-Tung Chang, Maciej Skolimowski, Simone Tanzi, Luigi Sasso
We present here an electrochemical sensor microsystem for the monitoring of pH. The all-polymeric device is comprised of a cyclic olefin copolymer substrate, a 200 nm-thin patterned layer of conductive polymer (PEDOT), and a 70 nm electropolymerized layer of a pH sensitive conductive polymer (polyaniline). The patterning of the fluidic (microfluidic channels) and conductive (wiring and electrodes) functional elements was achieved with a single soft PDMS mold via a single embossing step process. A post-processing treatment with ethylene glycol assured the functional enhancement of the electrodes, as demonstrated via an electrical and electrochemical characterization...
May 20, 2017: Sensors
https://www.readbyqxmd.com/read/28531096/the-lys-asp-tyr-triad-within-the-mite-allergen-der-p-1-propeptide-is-a-critical-structural-element-for-the-ph-dependent-initiation-of-the-protease-maturation
#5
Andy Chevigné, Vincenzo Campizi, Martyna Szpakowska, David Bourry, Marie-Eve Dumez, José C Martins, André Matagne, Moreno Galleni, Alain Jacquet
The major house dust mite allergen, Der p 1, is a papain-like cysteine protease expressed as an inactive precursor, proDer p 1, carrying an N-terminal propeptide with a unique structure. The maturation of the zymogen into an enzymatically-active form of Der p 1 is a multistep autocatalytic process initiated under acidic conditions through conformational changes of the propeptide, leading to the loss of its inhibitory ability and its subsequent gradual cleavage. The aims of this study were to characterize the residues present in the Der p 1 propeptide involved in the initiation of the zymogen maturation process, but also to assess the impact of acidic pH on the propeptide structure, the activity of Der p 1 and the fate of the propeptide...
May 20, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28531093/development-of-a-low-energy-x-ray-camera-for-the-imaging-of-secondary-electron-bremsstrahlung-x-ray-emitted-during-proton-irradiation-for-range-estimation
#6
Koki Ando, Mitsutaka Yamaguchi, Seiichi Yamamoto, Toshiyuki Toshito, Naoki Kawachi
Imaging of secondary electron bremsstrahlung x-ray emitted during proton irradiation is a possible method for measurement of the proton beam distribution in phantom. However, it is not clear that the method is used for range estimation of protons. For this purpose, we developed a low-energy x-ray camera and conducted imaging of the bremsstrahlung x-ray produced during irradiation of proton beams. We used a 20 mm  ×  20 mm  ×  1 mm finely grooved GAGG scintillator that was optically coupled to a one-inch square high quantum efficiency (HQE)-type position-sensitive photomultiplier tube to form an imaging detector...
May 22, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28530822/synthesis-and-membrane-properties-of-sulfonated-poly-arylene-ether-sulfone-statistical-copolymers-for-electrolysis-of-water-influence-of-meta-and-para-substituted-comonomers
#7
Amin Daryaei, Gregory C Miller, Jason Willey, Shreya Roy-Choudhury, Britannia Vondrasek, Dana Kazerooni, Matthew Russell Burtner, Cortney Kenneth Mittelsteadt, John J Lesko, Judy S Riffle, James E McGrath
Two series of high molecular weight disulfonated poly(arylene ether sulfone) random copolymers were synthesized as proton exchange membranes for high temperature water electrolyzers. These copolymers differ based on the position of the ether bonds on the aromatic rings. One series is comprised of fully para-substituted hydroquinone comonomer and the other series incorporated 25 mole % of a meta-substituted comonomer, resorcinol, and 75 mole % hydroquinone. The influence of the substitution position on water uptake and electrochemical properties of the membranes were investigated and compared to that of the state-of-the-art membrane, Nafion™...
May 22, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28530798/heterogeneous-molecular-catalysis-of-electrochemical-reactions-volcano-plots-and-catalytic-tafel-plots
#8
Cyrille Costentin, Jean-Michel Savéant
We analyze here, in the framework of heterogeneous mo-lecular catalysis the reasons of occurrence or non-occurrence of volcanoes upon plotting the kinetics of the catalytic reaction versus the stabilization free energy of the primary intermediate of the catalytic process. As in the case of homogeneous molecular catalysis or catalysis by surface active metallic sites, a strong motivation of such studies relates to modern energy challenges, particularly those involving small molecules such as water, hydrogen, oxygen, proton and carbon dioxide...
May 22, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28530710/engineering-protein-stability-with-atomic-precision-in-a-monomeric-miniprotein
#9
Emily G Baker, Christopher Williams, Kieran L Hudson, Gail J Bartlett, Jack W Heal, Kathryn L Porter Goff, Richard B Sessions, Matthew P Crump, Derek N Woolfson
Miniproteins simplify the protein-folding problem, allowing the dissection of forces that stabilize protein structures. Here we describe PPα-Tyr, a designed peptide comprising an α-helix buttressed by a polyproline II helix. PPα-Tyr is water soluble and monomeric, and it unfolds cooperatively with a midpoint unfolding temperature (TM) of 39 °C. NMR structures of PPα-Tyr reveal proline residues docked between tyrosine side chains, as designed. The stability of PPα is sensitive to modifications in the aromatic residues: replacing tyrosine with phenylalanine, i...
May 22, 2017: Nature Chemical Biology
https://www.readbyqxmd.com/read/28530608/rapid-accurate-and-simultaneous-measurement-of-water-and-oil-contents-in-the-fried-starchy-system-using-low-field-nmr
#10
Long Chen, Yaoqi Tian, Binghua Sun, Jinpeng Wang, Qunyi Tong, Zhengyu Jin
Fried starchy food is rich in oil that may pose a risk to health. For controlling of the oil uptake, a rapid and accurate method for the determination of oil content in the fried starchy food is important. In this study, low-field nuclear magnetic resonance (LF-NMR) was applied to simultaneously determine water and oil contents in the model fried starchy system. The proton signals from oil and water were verified and distinguished by desiccation at 105°C. There was no superposition between oil and water signals in the fried starch, making it possible for quantitative analysis of water and oil in a single test...
October 15, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28530582/proton-transfer-reaction-mass-spectrometry-ptr-ms-for-the-authentication-of-regionally-unique-south-african-lamb
#11
Sara W Erasmus, Magdalena Muller, Martin Alewijn, Alex H Koot, Saskia M van Ruth, Louwrens C Hoffman
The volatile fingerprints of South African lamb meat and fat were measured by proton-transfer mass spectrometry (PTR-MS) to evaluate it as an authentication tool. Meat and fat of the Longissimus lumborum (LL) of lambs from six different regions were assessed. Analysis showed that the volatile fingerprints were affected by the origin of the meat. The classification of the origin of the lamb was achieved by examining the calculated and recorded fingerprints in combination with chemometrics. Four different partial least squares discriminant analysis (PLS-DA) models were fitted to the data to classify lamb meat and fat samples into "region of origin" (six different regions) and "origin" (Karoo vs...
October 15, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28530581/metabolic-phenotyping-of-various-tea-camellia-sinensis-l-cultivars-and-understanding-of-their-intrinsic-metabolism
#12
Hyang-Gi Ji, Yeong-Ran Lee, Min-Seuk Lee, Kyeong Hwan Hwang, Eun-Hee Kim, Jun Seong Park, Young-Shick Hong
Recently, we selected three tea (Camellia sinensis) cultivars that are rich in taste, epigallocatechin-3-O-gallate (EGCG) and epigallocatechin-3-O-(3-O-methyl)-gallate (EGCG3″Me) and then cultivated them through asexual propagation by cutting in the same region. In the present study, proton nuclear magnetic resonance ((1)H NMR)-based metabolomics was applied to characterize the metabotype and to understand the metabolic mechanism of these tea cultivars including wild type tea. Of the tea leaf metabolite variations, reverse associations of amino acid metabolism with catechin compound metabolism were found in the rich-taste, and EGCG- and EGCG3″Me-rich tea cultivars...
October 15, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28530545/synthesis-and-biological-evaluation-of-curcumin-nitroxide-based-molecular-hybrids-as-antioxidant-and-anti-proliferative-agents
#13
Balázs Bognár, Muthulakshmi Kuppusamy, Esha Madan, Tamás Kálai, Mária Balog, József Jekő, Periannan Kuppusamy, Kálmán Hideg
BACKGROUND: Natural products and their derivatives are widely used to treat cancer and other diseases associated with ROS- and RNS-induced damages. METHODS: A series of paramagnetic modified curcumin analogues and 3,5-diarylidene-piperidones (DAP) have been designed, synthesized, and characterized on their anti-proliferative and antioxidant activity. RESULTS: Biological characterization of the new compounds supported the earlier results that incorporation of a nitroxide moiety or its precursor into curcumin or diarylidenylpiperidone (DAP) scaffolds resulted in anti-proliferative effect toward cancerous cell-lines in case of aryl hydroxy and/or methoxy substituent containing derivatives suggesting their potential for targeted therapeutic applications...
May 22, 2017: Medicinal Chemistry
https://www.readbyqxmd.com/read/28530400/probing-the-conformation-dependent-preferential-binding-of-ethanol-to-cationic-glycylalanylglycine-in-water-ethanol-by-vibrational-and-nmr-spectroscopy
#14
David DiGuiseppi, Bridget J Milorey, Gabrielle Lewis, Nina Kubatova, Stefanie Farrell, Harald Schwalbe, Reinhard Schweitzer-Stenner
The conformational propensity of amino acid residues is determined by an intricate balance of peptide-solvent and solvent-solvent interactions. In order to explore how the systematic replacement of water by a cosolvent affects the solvation of both amino acid backbone and side chains we, performed a combined vibrational spectroscopy and NMR study of cationic glycylalanylglycine (GAG) in different ethanol/water mixtures between 0 and 42 mole percent of ethanol. The classical model peptide N'-methylacetamide was used as a reference system to probe solvent-induced spectroscopic changes...
May 22, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28530393/structural-factors-that-alter-the-redox-potential-of-quinones-in-cyanobacterial-and-plant-photosystem-i
#15
Keisuke Kawashima, Hiroshi Ishikita
Using the cyanobacterial and plant photosystem I (PSI) crystal structures and by considering the protonation states of all titratable residues, redox potentials (Em) of the two phylloquinones--A1A and A1B--were calculated. The calculated Em values were Em(A1A) = -773 mV and Em(A1B) = -818 mV for the plant PSI structure and Em(A1A) = -612 mV and Em(A1B) = -719 mV for the cyanobacterial PSI structure. Our analysis of the PSI crystal structures suggested that the side-chain orientations of Lys-B542 and Gln-B678 in the cyanobacterial crystal structure differ from these side-chain orientations in the plant crystal structure...
May 22, 2017: Biochemistry
https://www.readbyqxmd.com/read/28530108/twelve-day-quintuple-regime-containing-four-antibiotics-as-a-rescue-therapy-for-helicobacter-pylori-eradication-in-the-central-region-of-portugal
#16
Diogo Branquinho, Nuno Miguel Peres de Almeida, Carlos Gregório, Adriano Casela, Maria Manuel Donato, Luís Tomé
BACKGROUND: Helicobacter pylori eradication rates with standard triple therapy in many countries are clinically unacceptable. Fluoroquinolone resistance is increasing and jeopardizing second-line regimens. There is a growing need for an effective strategy in patients who failed previous therapies. METHODS: This is a single-center, non-randomized clinical study conducted in the central region of Portugal. Sixty-four patients were included with a positive 13C-urea breath test (UBT) or histology for H...
May 22, 2017: Revista Española de Enfermedades Digestivas
https://www.readbyqxmd.com/read/28529962/picosecond-sulfur-k-edge-x-ray-absorption-spectroscopy-with-applications-to-excited-state-proton-transfer
#17
Benjamin E Van Kuiken, Matthew R Ross, Matthew L Strader, Amy A Cordones, Hana Cho, Jae Hyuk Lee, Robert W Schoenlein, Munira Khalil
Picosecond X-ray absorption (XA) spectroscopy at the S K-edge (∼2.4 keV) is demonstrated and used to monitor excited state dynamics in a small organosulfur molecule (2-Thiopyridone, 2TP) following optical excitation. Multiple studies have reported that the thione (2TP) is converted into the thiol (2-Mercaptopyridine, 2MP) following photoexcitation. However, the timescale and photochemical pathway of this reaction remain uncertain. In this work, time-resolved XA spectroscopy at the S K-edge is used to monitor the formation and decay of two transient species following 400 nm excitation of 2TP dissolved in acetonitrile...
July 2017: Structural Dynamics (Melville, N.Y.)
https://www.readbyqxmd.com/read/28529929/novel-and-effective-therapeutic-regimens-for-helicobacter-pylori-in-an-era-of-increasing-antibiotic-resistance
#18
REVIEW
Yi Hu, Yin Zhu, Nong-Hua Lu
Helicobacter pylori (H. pylori) is a common gastrointestinal bacterial strain closely associated with the incidence of chronic gastritis, peptic ulcers, gastric mucosa-associated lymphoid tissue lymphoma, and gastric cancer. A current research and clinical challenge is the increased rate of antibiotic resistance in H. pylori, which has led to a decreased H. pylori eradication rate. In this article, we review recent H. pylori infection and reinfection rates and H. pylori resistance to antibiotics, and we discuss the pertinent treatments...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28529896/advances-in-radiotherapy-techniques-and-delivery-for-non-small-cell-lung-cancer-benefits-of-intensity-modulated-radiation-therapy-proton-therapy-and-stereotactic-body-radiation-therapy
#19
REVIEW
Tejan P Diwanji, Pranshu Mohindra, Melissa Vyfhuis, James W Snider, Chaitanya Kalavagunta, Sina Mossahebi, Jen Yu, Steven Feigenberg, Shahed N Badiyan
The 21st century has seen several paradigm shifts in the treatment of non-small cell lung cancer (NSCLC) in early-stage inoperable disease, definitive locally advanced disease, and the postoperative setting. A key driver in improvement of local disease control has been the significant evolution of radiation therapy techniques in the last three decades, allowing for delivery of definitive radiation doses while limiting exposure of normal tissues. For patients with locally-advanced NSCLC, the advent of volumetric imaging techniques has allowed a shift from 2-dimensional approaches to 3-dimensional conformal radiation therapy (3DCRT)...
April 2017: Translational Lung Cancer Research
https://www.readbyqxmd.com/read/28529799/new-m-m-3-arsenates-the-framework-structures-of-agm-3-haso4-2-m-3-al-ga-and-m-gaas2o7-m-na-ag
#20
Karolina Schwendtner, Uwe Kolitsch
The crystal structures of hydro-thermally synthesized silver(I) aluminium bis-[hydrogen arsenate(V)], AgAl(HAsO4)2, silver(I) gallium bis-[hydrogen arsenate(V)], AgGa(HAsO4)2, silver gallium diarsenate(V), AgGaAs2O7, and sodium gallium diarsenate(V), NaGaAs2O7, were determined from single-crystal X-ray diffraction data collected at room temperature. The first two compounds are representatives of the MCV-3 structure type known for KSc(HAsO4)2, which is characterized by a three-dimensional anionic framework of corner-sharing alternating M(3+)O6 octa-hedra (M = Al, Ga) and singly protonated AsO4 tetra-hedra...
May 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
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