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https://www.readbyqxmd.com/read/29342358/synthesis-and-biological-characterization-of-aryl-uracil-inhibitors-of-hepatitis-c-virus-ns5b-polymerase-discovery-of-abt-072-a-trans-stilbene-analog-with-good-oral-bioavailability
#1
John Randolph, A Chris Krueger, Pamela Donner, John K Pratt, Dachun Liu, Christopher E Motter, Todd W Rockway, Mike D Tufano, Rolf Wagner, Hock B Lim, Jill M Beyer, Rubina Mondal, Neeta S Panchal, Lynn Colletti, Yaya Liu, Gennadiy Koev, Warren M Kati, Lisa E Hernandez, David W A Beno, Kenton L Longenecker, Kent D Stewart, Emily O Dumas, Akhteruzzaman Molla, Clarence Maring
ABT-072 is a non-nucleoside HCV NS5B polymerase inhibitor that was discovered as part of a program to identify new direct-acting antivirals (DAAs) for the treatment of HCV infection. This compound was identified during a medicinal chemistry effort to improve on an original lead, inhibitor 1, which we described in a previous publication. Replacement of the amide linkage in 1 with a trans-olefin resulted in improved compound permeability and solubility, and provided much better pharmacokinetic properties in preclinical species...
January 17, 2018: Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/29342239/hplc-estimation-ex-vivo-everted-sac-permeability-and-in-vivo-pharmacokinetic-studies-of-darunavir
#2
Vasanti M Suvarna, Preeti C Sangave
Darunavir ethanolate (DRV) is an efficient protease inhibitor (PI) used in the treatment of human immunodeficiency virus (HIV) type-1 patients. An isocratic reversed-phase HPLC method was developed to monitor concentration of darunavir in in vitro intestinal fluid samples in everted sac absorption model in the presence of bioenhancers, viz., piperine, quercetin, naringenin. The method was validated and successfully applied to everted sac and pharmacokinetic studies in rats. The absorption profiles of DRV and apparent permeability coefficients were determined...
January 12, 2018: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/29342216/in-vitro-activity-of-novel-glycopolymer-against-clinical-isolates-of-multidrug-resistant-staphylococcus-aureus
#3
Vidya P Narayanaswamy, Scott A Giatpaiboon, John Uhrig, Paul Orwin, William Wiesmann, Shenda M Baker, Stacy M Townsend
The incidence of multidrug-resistant (MDR) organisms, including methicillin-resistant Staphylococcus aureus (MRSA), is a serious threat to public health. Progress in developing new therapeutics is being outpaced by antibiotic resistance development, and alternative agents that rapidly permeabilize bacteria hold tremendous potential for treating MDR infections. A new class of glycopolymers includes polycationic poly-N (acetyl, arginyl) glucosamine (PAAG) is under development as an alternative to traditional antibiotic strategies to treat MRSA infections...
2018: PloS One
https://www.readbyqxmd.com/read/29342177/a-new-fluorescent-dye-accumulation-assay-for-parallel-measurements-of-the-abcg2-abcb1-and-abcc1-multidrug-transporter-functions
#4
Edit Szabó, Dóra Türk, Ágnes Telbisz, Nóra Kucsma, Tamás Horváth, Gergely Szakács, László Homolya, Balázs Sarkadi, György Várady
ABC multidrug transporters are key players in cancer multidrug resistance and in general xenobiotic elimination, thus their functional assays provide important tools for research and diagnostic applications. In this study we have examined the potential interactions of three key human ABC multidrug transporters with PhenGreen diacetate (PGD), a cell permeable fluorescent metal ion indicator. The non-fluorescent, hydrophobic PGD rapidly enters the cells and, after cleavage by cellular esterases, in the absence of quenching metal ions, PhenGreen (PG) becomes highly fluorescent...
2018: PloS One
https://www.readbyqxmd.com/read/29342127/enhancement-in-corneal-permeability-of-dissolved-carteolol-by-its-combination-with-magnesium-hydroxide-nanoparticles
#5
Noriaki Nagai, Sakie Yamaoka, Yuya Fukuoka, Miyu Ishii, Hiroko Otake, Kazutaka Kanai, Norio Okamoto, Yoshikazu Shimomura
We prepared magnesium hydroxide (MH) nanoparticles, and investigated their effect when combined with dissolved carteolol on the bioavailability and intraocular pressure (IOP)-reducing effect of carteolol. The carteolol was solved in saline containing additives (0.5% methylcellulose, 0.001% benzalkonium chloride, 0.5% mannitol; CRT-solution). MH nanoparticles were prepared by a bead mill method with additives. Then carteolol/MH microparticle and carteolol/MH nanoparticle fixed combinations (mCMFC and nCMFC) were prepared by mixing the CRT-solution and MH particles...
January 17, 2018: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/29342116/vegf-signaling-in-neurological-disorders
#6
REVIEW
Joon W Shim, Joseph R Madsen
Vascular endothelial growth factor (VEGF) is a potent growth factor playing diverse roles in vasculogenesis and angiogenesis. In the brain, VEGF mediates angiogenesis, neural migration and neuroprotection. As a permeability factor, excessive VEGF disrupts intracellular barriers, increases leakage of the choroid plexus endothelia, evokes edema, and activates the inflammatory pathway. Recently, we discovered that a heparin binding epidermal growth factor like growth factor (HB-EGF)-a class of EGF receptor (EGFR) family ligands-contributes to the development of hydrocephalus with subarachnoid hemorrhage through activation of VEGF signaling...
January 17, 2018: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/29341931/bioinspired-capsules-based-on-nanocellulose-xyloglucan-and-pectin-the-influence-of-capsule-wall-composition-on-permeability-properties
#7
T Paulraj, A V Riazanova, A J Svagan
Materials based on renewable biopolymers, selective permeability and stimuli-responsive release/loading properties play an important role in biomedical applications. Here, in order to mimic the plant primary cell-wall, microcapsules have been fabricated using cell wall polysaccharides, namely pectin, xyloglucan and cellulose nanofibers. For the first time, a large amount of xyloglucan was successfully included in such capsules. These capsules demonstrated stimuli-responsive (ON/OFF) permeability and biocompatibility...
January 13, 2018: Acta Biomaterialia
https://www.readbyqxmd.com/read/29341922/sustained-release-timolol-maleate-loaded-ocusert-based-on-biopolymer-composite
#8
Revathy V Nair, Shefrin S, Akhil Suresh, Anoop K R, Sreeja C Nair
In the present investigation, the effect of timolol maleate loaded ocuserts was studied as an alternative for conventional anti-glaucoma formulation. Ocuserts were prepared using natural polymer sodium alginate and ethyl cellulose. Physico-chemical properties along with drug entrapment efficiency (94-98%), content uniformity (93.1% ± 0.264-98.00% ± 0.321), in vitro drug release (83.42% ± 0.35 at end of 12 hours), ex vivo permeation all showed satisfactory results, which was found to follow zero order kinetics...
January 13, 2018: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29341916/effects-of-surfactant-based-permeation-enhancers-on-mannitol-permeability-histology-and-electrogenic-ion-transport-responses-in-excised-rat-colonic-mucosae
#9
Sam Maher, Joanne Heade, Fiona McCartney, Seona Waters, Sinéad B Bleiel, David J Brayden
Surfactant-based intestinal permeation enhancers (PEs) are constituents of several oral macromolecule formulations in clinical trials. This study examined the interaction of a test panel of surfactant-based PEs with isolated rat colonic mucosae mounted in Ussing chambers in an attempt to determine if increases in transepithelial permeability can be separated from induction of mucosal perturbation. The aim was to assess the effects of PEs on (i) apparent permeability coefficient (Papp) of [14C]-mannitol on (ii) histology score and (iii) short-circuit current (ΔIsc) responses to a cholinomimetic (carbachol, CCh)...
January 13, 2018: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/29341828/biosensors-for-spatiotemporal-detection-of-reactive-oxygen-species-in-cells-and-tissues
#10
Marie Erard, Sophie Dupre-Crochet, Oliver Nusse
Redox biology has become a major issue in numerous areas of physiology. Reactive oxygen species (ROS) have a broad range of roles from signal transduction to growth control and cell death. To understand the nature of these roles, accurate measurement of the reactive compounds is required. An increasing number of tools for ROS detection is available; however, specificity and sensitivity of these tools are often insufficient. Furthermore, their specificity has been rarely evaluated in complex physiological conditions...
January 17, 2018: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/29341666/mechanism-behind-erosive-bursts-in-porous-media
#11
R Jäger, M Mendoza, H J Herrmann
Erosion and deposition during flow through porous media can lead to large erosive bursts that manifest as jumps in permeability and pressure loss. Here we reveal that the cause of these bursts is the reopening of clogged pores when the pressure difference between two opposite sites of the pore surpasses a certain threshold. We perform numerical simulations of flow through porous media and compare our predictions to experimental results, recovering with excellent agreement shape and power-law distribution of pressure loss jumps, and the behavior of the permeability jumps as a function of particle concentration...
September 22, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/29341617/enhancing-docetaxel-delivery-to-multidrug-resistant-cancer-cells-with-albumin-coated-nanocrystals
#12
Sheryhan F Gad, Joonyoung Park, Ji Eun Park, Gihan N Fetih, Sozan S Tous, Wooin Lee, Yoon Yeo
Intravenous delivery of poorly water-soluble anticancer drugs such as docetaxel (DTX) is challenging due to the low bioavailability and the toxicity related to solubilizing excipients. Colloidal nanoparticles are used as alternative carriers, but low drug loading capacity and circulation instability limit their clinical translation. To address these challenges, DTX nanocrystals (NCs) were prepared using Pluronic F127 as an intermediate stabilizer and albumin as a functional surface modifier, which were previously found to be effective in producing small and stable NCs...
January 17, 2018: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/29341591/the-development-of-benzimidazole-based-clickable-probes-for-the-efficient-labeling-of-cellular-protein-arginine-deiminases-pads
#13
Venkatesh J Nemmara, Venkataraman Subramanian, Aaron Muth, Santanu Mondal, Ari J Salinger, Aaron J Maurais, Ronak Tilvawala, Eranthie Weerapana, Paul R Thompson
Citrullination is the post-translational hydrolysis of peptidyl-arginines to form peptidyl-citrulline, a reaction that is catalyzed by the protein arginine deiminases (PADs), a family of calcium-regulated enzymes. Aberrantly increased protein citrullination is associated with a slew of autoimmune diseases (e.g., rheumatoid arthritis (RA), multiple sclerosis, lupus, and ulcerative colitis) and certain cancers. Given the clear link between increased PAD activity and human disease, the PADs are therapeutically relevant targets...
January 17, 2018: ACS Chemical Biology
https://www.readbyqxmd.com/read/29341448/beneficial-actions-of-microbiota-derived-tryptophan-metabolites
#14
REVIEW
J J Galligan
Tryptophan is an important dietary amino acid and it is the precursor for 5-hydroxytryptamine synthesis in the nervous system and by enterochromaffin cells in the gut mucosa. Tryptophan is also metabolized by enzymes in the gut mucosa and also by enzymes produced by the gut microbiome. Diet and the microbiome can contribute to metabolic disease in part by causing intestinal inflammation and increased permeability. In this issue of Neurogastroenterology and Motility, Jennis et al. test the hypothesis that indole tryptophan metabolites produced by gut bacteria might be responsible for the anti-inflammatory and beneficial metabolic effects of the gut microbiome and Roux-en-Y gastric bypass surgery for weight loss by obese patients...
February 2018: Neurogastroenterology and Motility: the Official Journal of the European Gastrointestinal Motility Society
https://www.readbyqxmd.com/read/29341330/real-time-and-high-resolution-bioimaging-with-bright-aggregation-induced-emission-dots-in-short-wave-infrared-region
#15
Ji Qi, Chaowei Sun, Abudureheman Zebibula, Hequn Zhang, Ryan T K Kwok, Xinyuan Zhao, Wang Xi, Jacky W Y Lam, Jun Qian, Ben Zhong Tang
Fluorescence imaging in the spectral region beyond the conventional near-infrared biological window (700-900 nm) can theoretically afford high resolution and deep tissue penetration. Although some efforts have been devoted to developing a short-wave infrared (SWIR; 900-1700 nm) imaging modality in the past decade, long-wavelength biomedical imaging is still suboptimal owing to the unsatisfactory materials properties of SWIR fluorophores. Taking advantage of organic dots based on an aggregation-induced emission luminogen (AIEgen), herein microscopic vasculature imaging of brain and tumor is reported in living mice in the SWIR spectral region...
January 17, 2018: Advanced Materials
https://www.readbyqxmd.com/read/29341138/model-fitting-for-small-skin-permeability-data-sets-hyperparameter-optimisation-in-gaussian-process-regression
#16
Parivash Ashrafi, Yi Sun, Neil Davey, Roderick G Adams, Simon C Wilkinson, Gary Patrick Moss
OBJECTIVES: The aim of this study was to investigate how to improve predictions from Gaussian Process models by optimising the model hyperparameters. METHODS: Optimisation methods, including Grid Search, Conjugate Gradient, Random Search, Evolutionary Algorithm and Hyper-prior, were evaluated and applied to previously published data. Data sets were also altered in a structured manner to reduce their size, which retained the range, or 'chemical space' of the key descriptors to assess the effect of the data range on model quality...
January 17, 2018: Journal of Pharmacy and Pharmacology
https://www.readbyqxmd.com/read/29341029/in-vitro-and-in-situ-absorption-and-metabolism-of-sesquiterpenes-from-petasites-hybridus-extracts
#17
Lucia Disch, Kristina Forsch, Beate Siewert, Jürgen Drewe, Gert Fricker
Petasites hybridus extract is used in the treatment of seasonal allergic rhinitis. The aim of this study was to evaluate the active constituent petasin and its isomers isopetasin and neopetasin (petasins) in the P. hybridus extract Ze 339 for liberation, dissolution, absorption, and metabolism. The determination of pH-dependent thermodynamic solubility was performed via the shake-flask method. Petasins exhibited a low solubility that was pH independent. In vivo, the concentration of solute drugs is decreased continuously by intestinal absorption...
January 16, 2018: Planta Medica
https://www.readbyqxmd.com/read/29341021/assessment-of-blood-brain-barrier-leakage-with-gadolinium-enhanced-mri
#18
Min-Chi Ku, Sonia Waiczies, Thoralf Niendorf, Andreas Pohlmann
The integrity of the blood-brain barrier (BBB) can be noninvasively monitored by magnetic resonance imaging (MRI). Conventional MR contrast agents (CAs) containing gadolinium are used in association with MRI in routine clinical practice to detect and quantify BBB leakage. Under normal circumstances CAs do not cross the intact BBB. However due to their small size they extravasate from the blood into the brain tissue even when the BBB is partially compromised. Here we describe an MR method based on T1-weighted images taken prior to and after CA injection...
2018: Methods in Molecular Biology
https://www.readbyqxmd.com/read/29340982/controlled-release-of-the-nimodipine-loaded-self-microemulsion-osmotic-pump-capsules-development-and-characterization
#19
Yaping Huang, Sisi Zhang, Huifen Shen, Jinqing Li, Chongkai Gao
The present study was intended to develop a controlled released osmotic pump capsule based on Nimodipine (NM)-loaded self-microemulsifying drug delivery systems (SMEDDSs) in order to improve the low oral bioavailability of NM. To optimize the NM-loaded SMEDDS composition, the experiments of NM solubility in different oils, the pseudo-ternary phase diagram experiments and the different drug loading experiments were conducted in the preliminary screening studies. Controlled release of NM required an osmotic pump capsule comprising a coated semi-permeable capsule shell, plasticizer, and pore-forming agent...
January 16, 2018: AAPS PharmSciTech
https://www.readbyqxmd.com/read/29340082/reciprocal-sensitivity-of-diffuse-large-b-cell-lymphoma-cells-to-bcl-2-inhibitors-bird-2-versus-venetoclax
#20
Tamara Vervloessem, Haidar Akl, Thomas Tousseyn, Humbert De Smedt, Jan B Parys, Geert Bultynck
Bcl-2 is often upregulated in cancers to neutralize the BH3-only protein Bim at the mitochondria. BH3 mimetics (e.g. ABT-199 (venetoclax)) kill cancer cells by targeting Bcl-2's hydrophobic cleft and disrupting Bcl-2/Bim complexes. Some cancers with elevated Bcl-2 display poor responses towards BH3 mimetics, suggesting an additional function for anti-apoptotic Bcl-2 in these cancers. Indeed, Bcl-2 via its BH4 domain prevents cytotoxic Ca2+ release from the endoplasmic reticulum (ER) by directly inhibiting the inositol 1,4,5-trisphosphate receptor (IP3R)...
December 19, 2017: Oncotarget
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