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https://www.readbyqxmd.com/read/30517974/simultaneous-quantitation-of-metformin-and-dapagliflozin-in-human-plasma-by-lc-ms-ms-application-to-a-pharmacokinetic-study
#1
Priyanka A Shah, Pranav S Shrivastav, Jaivik V Shah, Archana George
A single LC-MS/MS assay is developed and validated for simultaneous determination of metformin and dapagliflozin in human plasma using ion-pair solid phase extraction. Chromatographic separation of the analytes and their internal standards was carried out on a reversed-phase ACE 5CN (150 × 4.6 mm, 5 μm) column using acetonitrile-15 mM ammonium acetate, pH 4.5 (70:30, v/v) as the mobile phase. To achieve higher sensitivity and selectivity for the analytes, mass spectrometric analysis was performed using polarity switching approach...
December 5, 2018: Biomedical Chromatography: BMC
https://www.readbyqxmd.com/read/30516400/intestinal-metaplasia-at-the-gastroesophageal-junction-is-associated-with-gastroesophageal-reflux-but-not-with-helicobacter-pylori-infection
#2
Mats Hall, Jörgen Wenner, Peter Scherman, Stefan Öberg
OBJECTIVE: Studies of the etiology of intestinal metaplasia (IM) at a normal appearing gastroesophageal junction (GEJ) are conflicting as associations with both H. Pylori (HP) infection and gastroesophageal reflux has been reported. The aim of this study was to investigate whether IM at the GEJ is associated with gastroesophageal reflux or HP infection. MATERIAL AND METHODS: Fifty asymptomatic volunteers and 149 patients with reflux symptoms underwent endoscopy with biopsies obtained from the gastric antrum and the squamocolumnar junction (SCJ)...
December 5, 2018: Scandinavian Journal of Gastroenterology
https://www.readbyqxmd.com/read/30515606/laser-flare-photometry-a-cost-effective-method-for-early-detection-of-endophthalmitis-after-intravitreal-injection-of-anti-vegf-agents
#3
Vânia Lages, Béatrice Gehrig, Carl P Herbort
BACKGROUND: Intravitreal injection of anti-vascular endothelial growth factor agents is the most common intraocular procedure worldwide, inevitably causing more cases of post-injection endophthalmitis. The purpose of this study was to evaluate the utility of laser flare photometry in monitoring inflammation after intravitreal injection of anti-vascular endothelial growth factor agents, particularly to detect early stage post-injection endophthalmitis. A retrospective case review was performed of all patients who underwent flare assessment by laser flare photometry before and after intravitreal injection of bevacizumab or aflibercept at the Centre for Ophthalmic Specialized Care in Lausanne, Switzerland, between January 2015 and May 2018...
December 4, 2018: Journal of Ophthalmic Inflammation and Infection
https://www.readbyqxmd.com/read/30513698/legionella-colonization-of-hotel-water-systems-in-touristic-places-of-greece-association-with-system-characteristics-and-physicochemical-parameters
#4
Maria A Kyritsi, Varvara A Mouchtouri, Antonis Katsioulis, Elina Kostara, Vasileios Nakoulas, Marina Hatzinikou, Christos Hadjichristodoulou
This study aimed to assess the colonization of hotel water systems in central Greece and Corfu by Legionella , and to investigate the association between physicochemical parameters and Legionella colonization. Standardized hygiene inspection was conducted in 51 hotels, and 556 water samples were analyzed for Legionella spp . Free chlorine concentration, pH, hardness, conductivity, and trace metals were defined in cold water samples. The results of inspections and chemical analyses were associated with the microbiological results using univariate and logistic regression analysis...
November 30, 2018: International Journal of Environmental Research and Public Health
https://www.readbyqxmd.com/read/30511779/experimental-pka-value-determination-of-all-ionizable-groups-of-a-hyper-stable-protein
#5
Heiner N Raum, Ulrich Weininger
Electrostatic interactions significantly contribute to the stability and function of proteins. The stabilizing or destabilizing effect of local charge is reflected in the perturbation of its pKa value of an ionizable group from the intrinsic pKa value. Here we study the charge network of a hyper stable dimeric protein (rhh protein from plasmid pRN1 from Sulfolobus islandicus) through experimental determination of the pKa values of all ionizable groups. Transitions were monitored by multiple NMR signals per ionizable group between pH 0 and 12...
December 4, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/30511719/fluorescence-based-detection-of-polychlorinated-biphenyls-pcbs-in-water-using-hydrophobic-interactions
#6
Irfan Ahmad, Jiaying Weng, A J Stromberg, J Z Hilt, T D Dziubla
Despite increasing controls in their production and disposal, persistent organic pollutants in water, even at concentrations below parts per million, represent an ongoing environmental health risk. Despite this concern, the detection of these compounds in water sources rely upon expensive, time consuming approaches that do not permit frequent monitoring and evaluation. In this work, a new fluorescence-based technique is presented for the detection of polychlorinated biphenyls (PCBs) in water. Benzopyrene (BaP) fluorescence was shown to increase with trace concentrations of aromatic organic pollutants...
December 4, 2018: Analyst
https://www.readbyqxmd.com/read/30510277/a-dna-nanomachine-chemically-resolves-lysosomes-in-live-cells
#7
KaHo Leung, Kasturi Chakraborty, Anand Saminathan, Yamuna Krishnan
Lysosomes are multifunctional, subcellular organelles with roles in plasma membrane repair, autophagy, pathogen degradation and nutrient sensing. Dysfunctional lysosomes underlie Alzheimer's disease, Parkinson's disease and rare lysosomal storage diseases, but their contributions to these pathophysiologies are unclear. Live imaging has revealed lysosome subpopulations with different physical characteristics including dynamics, morphology or cellular localization. Here, we chemically resolve lysosome subpopulations using a DNA-based combination reporter that quantitatively images pH and chloride simultaneously in the same lysosome while retaining single-lysosome information in live cells...
December 3, 2018: Nature Nanotechnology
https://www.readbyqxmd.com/read/30509916/novel-chemical-cocktails-in-inland-waters-are-a-consequence-of-the-freshwater-salinization-syndrome
#8
Sujay S Kaushal, Gene E Likens, Michael L Pace, Shahan Haq, Kelsey L Wood, Joseph G Galella, Carol Morel, Thomas R Doody, Barret Wessel, Pirkko Kortelainen, Antti Räike, Valerie Skinner, Ryan Utz, Norbert Jaworski
Widespread changes in water temperatures, salinity, alkalinity and pH have been documented in inland waters in North America, which influence ion exchange, weathering rates, chemical solubility and contaminant toxicity. Increasing major ion concentrations from pollution, human-accelerated weathering and saltwater intrusion contribute to multiple ecological stressors such as changing ionic strength and pH and mobilization of chemical mixtures resulting in the freshwater salinization syndrome (FSS). Here, we explore novel combinations of elements, which are transported together as chemical mixtures containing salts, nutrients and metals as a consequence of FSS...
December 3, 2018: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/30509590/performance-of-semi-continuous-anaerobic-co-digestion-of-poultry-manure-with-fruit-and-vegetable-waste-and-analysis-of-digestate-quality-a-bench-scale-study
#9
Patricia Bres, María Eugenia Beily, Brian Jonathan Young, Javier Gasulla, Mariano Butti, Diana Crespo, Roberto Candal, Dimitrios Komilis
Poultry manure (PM) can contain ammonium and ammonia nitrogen, which may inhibit the anaerobic process. The aim of this work was to evaluate the performance of anaerobic digestion of PM co-digested with fruit and vegetable waste. Two semi-continuous bench scale (19L) stirred tank reactors were used. The operating conditions were: 34.5 °C, 2 gVS/L.d (organic load rate), 28 d of hydraulic retention time and 100 revolutions per m (1 h × 3 times by day) for the agitation. The reactors were fed PM and a mixture of PM and fruit and vegetable waste (FVW) at equal proportions (based on wet weight)...
December 2018: Waste Management
https://www.readbyqxmd.com/read/30505488/obstructive-sleep-apnea-in-patients-with-chronic-thromboembolic-pulmonary-hypertension
#10
Xue Yu, Zhiwei Huang, Yi Zhang, Zhihong Liu, Qin Luo, Zhihui Zhao, Qing Zhao, Liu Gao, Qi Jin, Lu Yan
Background: Due to its effects, like an exaggerated negative intrathoracic pressure, sympathetic activation, systemic inflammation, oxidative stress, and endothelial dysfunction, obstructive sleep apnea (OSA) has been involved as a cause in multiple cardiovascular diseases. These diseases include coronary artery disease, hypertension, heart failure, and pulmonary hypertension (PH). Furthermore, OSA often coexists with chronic thromboembolic pulmonary hypertension (CTEPH) in clinical practice...
October 2018: Journal of Thoracic Disease
https://www.readbyqxmd.com/read/30502390/development-of-a-bioreactor-system-for-cytotoxic-evaluation-of-pharmacological-compounds-in-living-cells-using-nmr-spectroscopy
#11
Josué Carvalho, Sara Alves, M Margarida C A Castro, Carlos F G C Geraldes, João A Queiroz, Carla P Fonsec, Carla Cruz
INTRODUCTION: The evaluation of drug's cytotoxicity is a crucial step in the development of new pharmacological compounds. 31 P NMR can be a tool for toxicological screening, as it enables the study of drugs' cytotoxicity and their effect on cell energy metabolism in a real-time, in a non- invasive and non-destructive way. This paper details a step-by-step protocol to implement a bioreactor system able to maintain cell viability during NMR acquisitions, at high cell densities and for several hours, enabling toxicological evaluation of pharmacological compounds in living cells...
November 28, 2018: Journal of Pharmacological and Toxicological Methods
https://www.readbyqxmd.com/read/30502139/lf-1-h-nmr-t-2-relaxation-rate-as-affected-by-water-addition-nacl-and-ph-in-fresh-frozen-and-cooked-minced-hake
#12
Maureen Duflot, Isabel Sánchez-Alonso, Guillaume Duflos, Mercedes Careche
Low-Field Nuclear Magnetic Resonance of proton transverse relaxation signal (T2 ) was monitored in hake (Merluccius merluccius) mince with different thermal histories (fresh, frozen, cooked) as affected by pH, water and NaCl addition, and it was related to water holding capacity (WHC). Modifications of T2 signals were found in terms of changes in relaxation times and relative abundance of the relaxation components. The relaxation rate of the major component (1/T21 ) increased significantly upon frozen storage or pH increase, whereas water or NaCl addition had the opposite effect...
March 30, 2019: Food Chemistry
https://www.readbyqxmd.com/read/30501593/tansition-metal-based-prodrugs-for-anticancer-drug-delivery
#13
Ana Maria Faísca Phillips, Armando J L Pombeiro
Transition metal complexes, of which the platinum(II) cisplatin complex is an example, have been used in medicine to treat cancer for more than 40 years. Although many successes have been achieved, there are problems associated with the use of these drugs, such as side effects and drug resistance. Converting them into prodrugs, to make them more inert, so that they can travel to the tumour site unchanged and release the drug in its active form only there, is a strategy which is the subject of much research nowadays...
December 3, 2018: Current Medicinal Chemistry
https://www.readbyqxmd.com/read/30501107/application-of-a-novel-potential-probiotic-lactobacillus-paracasei-strain-isolated-from-kefir-grains-in-the-production-of-feta-type-cheese
#14
Ioanna Mantzourani, Antonia Terpou, Athanasios Alexopoulos, Pelagia Chondrou, Alex Galanis, Argyro Bekatorou, Eugenia Bezirtzoglou, Athanasios A Koutinas, Stavros Plessas
In the present study 38 lactic acid bacteria strains were isolated from kefir grains and were monitored regarding probiotic properties in a series of established in vitro tests, including resistance to low pH, resistance to pepsin and pancreatin, and tolerance to bile salts, as well as susceptibility against common antibiotics. Among them, the strain SP3 displayed potential probiotic properties. Multiplex PCR analysis indicated that the novel strain belongs to the paracasei species. Likewise, the novel strain ( Lactobacillus paracasei SP3) was applied as a starter culture for Feta-type cheese production...
November 29, 2018: Microorganisms
https://www.readbyqxmd.com/read/30500789/diagnosis-of-undesired-scenarios-in-hydrogen-production-by-photo-fermentation
#15
Isaac Monroy, Germán Buitrón
This study presents the use of a machine learning method from the artificial intelligence area, such as the support vector machines, applied to the construction of data-based classification models for diagnosing undesired scenarios in the hydrogen production process by photo-fermentation, which was carried out by an immobilized photo-bacteria consortium. The diagnosis models were constructed with data obtained from simulations run with a mechanistic model of the process and assessed on both modelled and experimental batches...
November 2018: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://www.readbyqxmd.com/read/30500608/electroactive-fluorescent-false-neurotransmitter-ffn102-partially-replaces-dopamine-in-pc12-cell-vesicles
#16
Lihui Hu, Alexandra Savy, Laurence Grimaud, Manon Guille-Collignon, Frédéric Lemaître, Christian Amatore, Jérôme Delacotte
In the last decade, following fluorescent dyes and protein tags, pH sensitive false fluorescent neurotransmitters (FFN) were introduced and were valuable for labeling secretory vesicles and monitoring exocytosis at living cells. In particular, the synthetic analog of neurotransmitters FFN102 was shown to be an electroactive probe. Here, we show that FFN102 is suitable to be used as a bioanalytic probe at the widely used PC12 cell model. FFN102 was uptaken in the secretory vesicles of PC12 cells, partially replacing the endogenous dopamine stored in these vesicles...
November 12, 2018: Biophysical Chemistry
https://www.readbyqxmd.com/read/30500031/a-ph-responsive-fluorescent-probe-based-on-dye-modified-i-motif-nucleic-acids
#17
Pan Li, Zhe Chen, Yishun Huang, Jing Li, Fan Xiao, Shiyao Zhai, Zhiming Wang, Xuanjun Zhang, Leilei Tian
A new DNA-based fluorescent probe, which is a hybrid molecule of an i-motif forming sequence (IFS) and mono-functionalized tetraphenylethene (TPE), has been synthesized and investigated. A distinct pH-responsive aggregation-induced emission (AIE) effect has been observed from this hybrid molecule, i.e. the fluorescence of TPE will be turned on when the IFS part folds up under acidic conditions. According to the fact that a hybrid molecule with a relatively rigid structure shows a more obvious AIE effect, and whose nano-sized aggregates are formed at a high concentration, we assume that the solubility of the hybrid molecule in water will be reduced due to IFS folding, resulting in aggregation and the resultant AIE effect...
November 30, 2018: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/30498489/the-glutaminase-dependent-acid-resistance-system-qualitative-and-quantitative-assays-and-analysis-of-its-distribution-in-enteric-bacteria
#18
Eugenia Pennacchietti, Chiara D'Alonzo, Luca Freddi, Alessandra Occhialini, Daniela De Biase
Neutralophilic bacteria have developed several strategies to overcome the deleterious effects of acid stress. In particular, the amino acid-dependent systems are widespread, with their activities overlapping, covering a rather large pH range, from 6 to <2. Recent reports showed that an acid resistance (AR) system relying on the amino acid glutamine (AR2_Q), the most readily available amino acid in the free form, is operative in Escherichia coli, Lactobacillus reuteri , and some Brucella species. This system requires a glutaminase active at acidic pH and the antiporter GadC to import L -glutamine and export either glutamate (the glutamine deamination product) or GABA...
2018: Frontiers in Microbiology
https://www.readbyqxmd.com/read/30497006/impact-of-oral-astringent-stimuli-on-surface-charge-and-morphology-of-the-protein-rich-pellicle-at-the-tooth-saliva-interphase
#19
Ralf Zimmermann, Judith Delius, Jens Friedrichs, Susanne Stehl, Thomas Hofmann, Christian Hannig, Melanie Rehage, Carsten Werner, Matthias Hannig
The proteinaceous pellicle layer, which develops upon contact with saliva on the surface of teeth, is important for the formation of oral biofilms and for the protection of teeth from abrasion and chemically induced erosion. Astringent food ingredients comprising polyphenols, cationic macromolecules, and multivalent metal salts are known to interact with the pellicle. However, astringent-induced changes in the physicochemical properties of the tooth-saliva interphase are not yet completely understood. Here we provide comprehensive insights into interfacial charging, ultrastructure, thickness, and surface roughness of the pellicles formed on the model substrates silicon oxide (SiO2 ), Teflon® AF, and hydroxyapatite, as well as on bovine enamel before and after incubation with the astringents epigallocatechin gallate, tannic acid, iron(III) salt, lysozyme, and chitosan...
November 16, 2018: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/30488389/microfluidic-free-flow-isoelectric-focusing-with-real-time-pi-determination
#20
Stefan Nagl
Free-flow electrophoresis (FFE) may be used for continuous and preparative separation of a wide variety of biomolecules. Isoelectric focusing (IEF) provides for the separation of compounds according to their isoelectric point (pI). Here we describe a microfluidic chip-based protocol for the fabrication, application, and optical monitoring of free-flow isoelectric focusing (FFIEF) of proteins and peptides on the microscale with optical surveillance of the microscopic pH gradient provided by an integrated pH sensing layer...
2019: Methods in Molecular Biology
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