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Contrast kinetics

Michael P Saddoris
Repeated self-administration of cocaine is associated with impairments in motivated behaviors as well as alterations in both dopamine (DA) release and neural signaling within the nucleus accumbens (NAc). These impairments are present even after several weeks of abstinence from drug taking, suggesting that the self-administration experience induces long-lasting neuroplastic alterations in the mesolimbic DA circuit. To understand these changes at the terminal level, rats were allowed to self-administer either cocaine intravenously (∼1 mg/kg per infusion) or water to a receptacle (control) in 2-h sessions over 14 days, followed by 30 days of enforced abstinence...
September 2016: ENeuro
Keiko Tawa, Shohei Yamamura, Chisato Sasakawa, Izumi Shibata, Masatoshi Kataoka
Plasmonic chip was applied to the live cancer cell imaging. The epithelial cell adhesion molecule (EpCAM) is a surface marker that can be used to classify breast cancer cell lines into distinct differentiation states. EpCAM and the nuclei of two kinds of living breast cancer cells, MDA-MB231 and MCF-7, were stained with allophycocyanin (APC)-labeled anti-EpCAM antibody and 4,6-diamidino-2-phenylindole (DAPI), respectively, and the cells were scattered on either a plasmonic chip (metal-coated wavelength-scale grating substrate) or a control glass slide...
October 18, 2016: ACS Applied Materials & Interfaces
S Noe, A von Werder, R Iakoubov, H Schneider, M Thaler, P Luppa, B Neu
Purpose: To investigate the kinetics of adrenocorticotropin (ACTH) following oral metyrapone administration and describe differences between ACTH-deficient and non-ACTH-deficient subjects. Methods: Patients from a tertiary endocrine center at a University Hospital in Munich, Germany, were tested for secondary adrenal insufficiency in a regular patient care setting. Metyrapone (Metopirone, HRA Pharma, France) was administered with a dosage of 40 mg/kg bodyweight at 8 a.m. Consecutive levels of ACTH were determined at 0, 60, 120, 180, and 240 min...
October 17, 2016: Experimental and Clinical Endocrinology & Diabetes
Sudath Hapuarachchige, Dmitri Artemov
Click chemistry provides fast, convenient, versatile, and reliable chemical reactions that take place between pairs of functional groups of small molecules that can be purified without chromatographic methods. Due to the fast kinetics and low or no elimination of byproducts, click chemistry is a promising approach that is rapidly gaining acceptance in drug discovery, radiochemistry, bioconjugation, and nanoscience applications. Increasing use of click chemistry in synthetic procedures or as a bioconjugation technique in diagnostic imaging is occurring because click reactions are fast, provide a quantitative yield, and produce a minimal amount of nontoxic byproducts...
October 2016: Topics in Magnetic Resonance Imaging: TMRI
Qiang Wang, Liping Huang, Yuzhen Pan, Xie Quan, Gianluca Li Puma
The role of Fe(III) was investigated as an electron-shuttle mediator to enhance the reduction rate of the toxic heavy metal hexavalent chromium (Cr(VI)) in wastewaters, using microbial fuel cells (MFCs). The direct reduction of chromate (CrO4(-)) and dichromate (Cr2O7(2-)) anions in MFCs was hampered by the electrical repulsion between the negatively charged cathode and Cr(VI) functional groups. In contrast, in the presence of Fe(III), the conversion of Cr(VI) and the cathodic coulombic efficiency in the MFCs were 65...
October 6, 2016: Journal of Hazardous Materials
Patricie Burda, Terttu Suormala, Dorothea Heuberger, Alexandra Schäfer, Brian Fowler, D Sean Froese, Matthias R Baumgartner
5,10-Methylenetetrahydrofolate reductase (MTHFR) catalyzes the NADPH-dependent reduction of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate using FAD as the cofactor. Severe MTHFR deficiency is the most common inborn error of folate metabolism, resulting in hyperhomocysteinemia and homocystinuria. Approximately 70 missense mutations have been described that cause severe MTHFR deficiency, however, in most cases their mechanism of dysfunction remains unclear. Few studies have investigated mutational specific defects; most of these assessing only activity levels from a handful of mutations using heterologous expression...
October 14, 2016: Journal of Inherited Metabolic Disease
Francesco Gaetano Casino, Carlo Basile
BACKGROUND: The recent interest in incremental haemodialysis (HD) is hindered by the current prescription based on a fixed target model (FTM) for the total (dialytic + renal) equivalent continuous clearance (ECC). The latter is expressed either as standard Kt/V (stdKt/V), i.e. the pre-dialysis averaged concentration of urea-based ECC, or EKRc, i.e. the time averaged concentration-based ECC, corrected for volume (V) = 40 L. Accordingly, there are two different targets: stdKt/V = 2.3 volumes per week (v/wk) and EKRc = 13 mL/min/40 L...
October 14, 2016: Nephrology, Dialysis, Transplantation
Prakasha Gowda, Thomas E Spratt
4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent tobacco carcinogen that forms mutagenic DNA adducts including O(6)-methyl-2'-deoxyguanosine (O(6)-Me-dG), O(6)-[4-(3-pyridyl)-4-oxobut-1-yl]-dG (O6-POB-dG), O(2)-methylthymidine (O(2)-Me-dT), and O(2)-POB-dT. We evaluated the ability of human DNA polymerase ν to bypass this damage to evaluate the structural constraints on substrates for pol ν and to evaluate if there is kinetic evidence suggesting the in vivo activity of pol ν on tobacco-induced DNA damage...
October 14, 2016: Chemical Research in Toxicology
Jia Feng, Shengli Shi, Liangyu Pei, Junping Lv, Qi Liu, Shulian Xie
Phenol components are major industry contaminants of aquatic environment. Among all practical methods for removing phenol substances from polluted water, activated carbon absorption is the most effective way. Here, we have produced low-cost activated carbon using Polygonum orientale Linn, a wide spreading species with large biomass. The phenol adsorption ability of this activated carbon was evaluated at different physico-chemical conditions. Average equilibrium time for adsorption was 120 min. The phenol adsorption ability of the P...
2016: PloS One
Erica Belgio, Stefano Santabarbara, David Bína, Eliška Trsková, Miroslava Herbstová, Radek Kaňa, Giuseppe Zucchelli, Ondřej Prášil
In the present work, we report the first comparative spectroscopic investigation between Photosystems I (PSI) complexes isolated from two red clade algae. Excitation energy transfer was measured in PSI from Chromera velia, an alga possessing a split PsaA protein, and from the model diatom Phaeodactylum tricornutum. In both cases, the estimated effective photochemical trapping time was in the 15-25ps range, i.e. twice as fast as higher plants. In contrast to green phototrophs, the trapping time was rather constant across the whole emission spectrum...
October 11, 2016: Biochimica et Biophysica Acta
Takashi Daiho, Kazuo Yamasaki, Stefania Danko, Hiroshi Suzuki
The cytoplasmic Actuator domain of sarco(endo)plasmic reticulum Ca(2+)-ATPase undergoes large rotational movements that influence the distant transmembrane transport sites, and a long second transmembrane helix (M2) connected with this domain plays critical roles in transmitting motions between the cytoplasmic catalytic domains and transport sites. Here we explore possible structural roles of Gly(105) between the cytoplasmic (M2c) and transmembrane (M2m) segments of M2 by introducing mutations that limit/increase conformational freedom...
October 12, 2016: Journal of Biological Chemistry
Leah D McGurn, Maryam Moazami-Goudarzi, Sean A White, Tannu Suwal, Beant Brar, Jason Q Tang, George S Espie, Matthew S Kimber
CcaA is a b-carbonic anhydrase that is a component of the carboxysomes of a subset of b-cyanobacteria. This protein, which has a characteristic C-terminal extension of unknown function, is recruited to the carboxysome via interactions with CcmM, which is itself a γ-carbonic anhydrase homolog with enzymatic activity in many, but not all cyanobacteria. We have determined the structure of CcaA from Synechocystis sp. PCC 6803 at 1.45 Å. In contrast to the dimer of dimers organization of most bacterial β-carbonic anhydrases, or the loose dimer-of-dimers-of-dimers organization found in the plant enzymes, CcaA shows a well-packed trimer-of-dimers organization...
October 11, 2016: Biochemical Journal
Haroon Ur Rashid, Marco Antonio Utrera Martines, Juliana Jorge, Paula Martin de Moraes, Muhammad Naveed Umar, Kamin Khan, Hanif Ur Rehman
Magnetic Resonance Imaging (MRI) is a noninvasive radiology technique used to examine the internal organs of human body. It is useful for the diagnosis of structural abnormalities in the body. Contrast agents are used to increase the sensitivity of this technique. 1,4,7,10-Tetraazacyclododecane (cyclen) is a macrocyclic tetraamine. Its derivatives act as useful ligands to produce stable complexes with Gd(3+) ion. Such chelates are investigated as MRI contrast agents. Free Gd(3+) ion is extremely toxic for in vivo use...
October 1, 2016: Bioorganic & Medicinal Chemistry
Adam Michael Scheer, Arkke J Eskola, David L Osborn, Leonid Sheps, Craig Allen Taatjes
The pulsed photolytic chlorine-initiated oxidation of diethyl ketone [DEK; (CH3CH2)2C=O], 2,2,4,4-d4-DEK [d4-DEK; (CH3CD2)2C=O] and 1,1,1,5,5,5-d6-DEK [d6-DEK; (CD3CH2)2C=O] is studied at 8 Torr and 1 - 2 atm and from 400 - 625 K. Cl atoms produced by laser photolysis react with diethyl ketone to form either primary (3-pentan-on-1-yl, RP) or secondary (3-pentan-on-2-yl, RS¬¬) radicals, which in turn react with O2. Multiplexed time of flight mass spectrometry, coupled to either a hydrogen discharge lamp or tunable synchrotron photoionizing radiation, is used to detect products as a function of mass, time and photon energy...
October 11, 2016: Journal of Physical Chemistry. A
Takahisa Ohta, Yasuhiko Hashida, Fumiyoshi Yamashita, Mitsuru Hashida
A novel sustained release formulation of mitomycin C (MMC) was developed by employing single-walled carbon nanotubes (SWCNTs) wrapped by designed peptide with polyethylene glycol (PEG) modification (pegylation) as a nano-scale molecular platform. The amino groups of polycationic and amphiphilic H-(-Cys-Trp-Lys-Gly-)(-Lys-Trp-Lys-Gly-)6-OH [CWKG(KWKG)6] peptide associated with SWCNTs were modified using PEG with 12 units (PEG12) to improve the dispersion stability of the composite. Then thiol groups of peptide were conjugated with MMC using N-ε-maleimidocaproic acid (EMCA) as a linker via transformation of aziridine group of MMC...
2016: Biological & Pharmaceutical Bulletin
Adrianus Indrat Aria, Kenichi Nakanishi, Long Xiao, Philipp Braeuninger-Weimer, Abhay A Sagade, Jack A Alexander-Webber, Stephan Hofmann
Atomic layer deposition (ALD) of ultra-thin aluminum oxide (AlOx) films was systematically studied on supported CVD graphene. We show that by extending the precursor residence time, using either a multiple-pulse sequence or a soaking period, sub-2nm thin continuous AlOx films can be achieved directly on graphene using standard H2O and trimethylaluminum (TMA) precursors even at a high deposition temperatures of 200°C, without the use of surfactants or other additional graphene surface modifications. To obtain conformal nucleation a precursor residence time of >2s is needed, which is not prohibitively long but sufficient to account for the slow adsorption kinetics of the graphene surface...
October 10, 2016: ACS Applied Materials & Interfaces
M Ravichandran, Goldie Oza, S Velumani, Jose Tapia Ramirez, Francisco Garcia-Sierra, Norma Barragan Andrade, A Vera, L Leija, Marco A Garza-Navarro
A multifunctional magneto-plasmonic CoFe2O4@Au core-shell nanoparticle was developed by iterative-seeding based method. This nanocargo consists of a cobalt ferrite kernel as a core (Nk) and multiple layers of gold as a functionalizable active stratum, (named as Nk@A after fifth iteration). Nk@A helps in augmenting the physiological stability and enhancing surface plasmon resonance (SPR) property. The targeted delivery of Doxorubicin using Nk@A as a nanopayload is demonstrated in this report. The drug release profile followed first order rate kinetics optimally at pH 5...
October 10, 2016: Scientific Reports
C Satriano, G Lupo, C Motta, C D Anfuso, P Di Pietro, B Kasemo
Hybrid nanoassemblies of ferritin and silica-supported lipid bilayers (ferritin-SLBs) have been prepared and tested for the adhesion, spreading and proliferation of retinal microvascular endothelial cells (ECs). Lipid membranes with varying surface charge were obtained by mixing cationic 1-palmitoyl-2-oleoyl-sn-glycero-3-ethylphosphocholine (POEPC) with zwitterionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) at increasing POPC/POEPC ratios. The supported bilayer formation and their subsequent interaction processes with ferritin were studied at the pH of 7...
October 4, 2016: Colloids and Surfaces. B, Biointerfaces
Manuela Cardi, Mirko Zaffagnini, Alessia De Lillo, Daniela Castiglia, Kamel Chibani, José Manuel Gualberto, Nicolas Rouhier, Jean-Pierre Jacquot, Sergio Esposito
A cDNA coding for a plastidic P2-type G6PDH isoform from poplar (Populus tremula x tremuloides) has been used to express and purify to homogeneity the mature recombinant protein with a N-terminus His-tag. The study of the kinetic properties of the recombinant enzyme showed an in vitro redox sensing modulation exerted by reduced DTT. The interaction with thioredoxins (TRXs) was then investigated. Five cysteine to serine variants (C145S - C175S - C183S - C195S - C242S) and a variant with a double substitution for Cys(175) and Cys(183) (C175S/C183S) have been generated, purified and biochemically characterized in order to investigate the specific role(s) of cysteines in terms of redox regulation and NADPH-dependent inhibition...
November 2016: Plant Science: An International Journal of Experimental Plant Biology
Paul Kelley, Guy A Edouard, Sibo Lin, Theodor Agapie
Study of the kinetics of intramolecular aryl ether C-O bond cleavage by Ni was facilitated by access to a family of metal complexes supported by diphosphines with pendant aryl-methyl ethers. The nature of the aryl substituents was found to have little effect on the rate of cleavage. In contrast, soluble Lewis acidic additives accelerate the aryl ether cleavage dramatically. The effect of AlMe3 was studied in detail, and showed an increase in rate by several orders of magnitude. Low temperature NMR spectroscopy studies demonstrate quantitative coordination of ether to Al...
September 26, 2016: Chemistry: a European Journal
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