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https://www.readbyqxmd.com/read/27926854/structural-characterization-and-statistical-mechanical-model-of-epidermal-patterns
#1
Duyu Chen, Wen Yih Aw, Danelle Devenport, Salvatore Torquato
In proliferating epithelia of mammalian skin, cells of irregular polygon-like shapes pack into complex, nearly flat two-dimensional structures that are pliable to deformations. In this work, we employ various sensitive correlation functions to quantitatively characterize structural features of evolving packings of epithelial cells across length scales in mouse skin. We find that the pair statistics in direct space (correlation function) and Fourier space (structure factor) of the cell centroids in the early stages of embryonic development show structural directional dependence (statistical anisotropy), which is a reflection of the fact that cells are stretched, which promotes uniaxial growth along the epithelial plane...
December 6, 2016: Biophysical Journal
https://www.readbyqxmd.com/read/27926853/a-dynamical-threshold-for-cardiac-delayed-afterdepolarization-mediated-triggered-activity
#2
Michael B Liu, Christopher Y Ko, Zhen Song, Alan Garfinkel, James N Weiss, Zhilin Qu
Ventricular myocytes are excitable cells whose voltage threshold for action potential (AP) excitation is ∼-60 mV at which INa is activated to give rise to a fast upstroke. Therefore, for a short stimulus pulse to elicit an AP, a stronger stimulus is needed if the resting potential lies further away from the INa threshold, such as in hypokalemia. However, for an AP elicited by a long duration stimulus or a diastolic spontaneous calcium release, we observed that the stimulus needed was lower in hypokalemia than in normokalemia in both computer simulations and experiments of rabbit ventricular myocytes...
December 6, 2016: Biophysical Journal
https://www.readbyqxmd.com/read/27925247/does-flexible-arterial-tubing-retain-more-hemodynamic-energy-during-pediatric-pulsatile-extracorporeal-life-support
#3
Shigang Wang, Allen R Kunselman, Akif Ündar
The objective of this study was to evaluate the hemodynamic performance and energy transmission of flexible arterial tubing as the arterial line in a simulated pediatric pulsatile extracorporeal life support (ECLS) system. The ECLS circuit consisted of a Medos Deltastream DP3 diagonal pump head, Medos Hilite 2400 LT oxygenator, Biomedicus arterial/venous cannula (10 Fr/14 Fr), 3 feet of polyvinyl chloride (PVC) arterial tubing or latex rubber arterial tubing, primed with lactated Ringer's solution and packed red blood cells (hematocrit 40%)...
December 7, 2016: Artificial Organs
https://www.readbyqxmd.com/read/27925198/cancer-cell-plasticity-rapid-reversal-of-chemosensitivity-and-expression-of-stemness-markers-in-lung-and-breast-cancer-tumorspheres
#4
Juan Sebastian Yakisich, Neelam Azad, Vivek Kaushik, Anand Krishnan V Iyer
In cancer cells, the reversible nature of the stemness status in terms of chemoresistance has been poorly characterized. In this study, we have simulated on cycle of environmental conditions to study such reversibility by first generating floating tumorspheres (FTs) from lung and breast cancer cells by culturing them in serum-free media without the addition of any external mitogenic stimulation, and subsequently (after two weeks) re-incubating them back in serum-containing media to simulate routine culture conditions (RCCs)...
December 7, 2016: Journal of Cellular Physiology
https://www.readbyqxmd.com/read/27925181/estimation-of-the-tumor-size-at-cure-threshold-among-aggressive-non-small-cell-lung-cancers-nsclcs-evidence-from-the-surveillance-epidemiology-and-end-results-program-seer-and-the-national-lung-screening-trial-nlst
#5
Deborah L Goldwasser
The National Lung Screening Trial (NLST) demonstrated that non-small cell lung cancer (NSCLC) mortality can be reduced by a program of annual CT screening in high-risk individuals. However, CT screening regimens and adherence vary, potentially impacting the lung cancer mortality benefit. We defined the NSCLC cure threshold as the maximum tumor size at which a given NSCLC would be curable due to early detection. We obtained data from 518,234 NSCLCs documented in the U.S. SEER cancer registry between 1988 and 2012 and 1,769 NSCLCs detected in the NLST...
December 7, 2016: International Journal of Cancer. Journal International du Cancer
https://www.readbyqxmd.com/read/27924908/development-of-novel-noninvasive-prenatal-testing-protocol-for-whole-autosomal-recessive-disease-using-picodroplet-digital-pcr
#6
Mun Young Chang, Ah Reum Kim, Min Young Kim, Soyoung Kim, Jinsun Yoon, Jae Joon Han, Soyeon Ahn, Changsoo Kang, Byung Yoon Choi
We developed a protocol of noninvasive prenatal testing (NIPT), employing a higher-resolution picodroplet digital PCR, to detect genetic imbalance in maternal plasma DNA (mpDNA) caused by cell-free fetal DNA (cffDNA). In the present study, this approach was applied to four families with autosomal recessive (AR) congenital sensorineural hearing loss. First, a fraction of the fetal DNA in mpDNA was calculated. Then, we made artificial DNA mixtures (positive and negative controls) to simulate mpDNA containing the fraction of cffDNA with or without mutations...
December 7, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27924859/nano-cones-for-broadband-light-coupling-to-high-index-substrates
#7
J Buencuerpo, L Torné, R Álvaro, J M Llorens, M L Dotor, J M Ripalda
The moth-eye structure has been proposed several times as an antireflective coating to replace the standard optical thin films. Here, we experimentally demonstrate the feasibility of a dielectric moth-eye structure as an antireflective coating for high-index substrates, like GaAs. The fabricated photonic crystal has Si3N4 cones in a square lattice, sitting on top of a TiO2 index matching layer. This structure attains 1.4% of reflectance power losses in the operation spectral range of GaAs solar cells (440-870 nm), a 12...
December 7, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27924846/structure-and-dynamics-of-a-constitutively-active-neurotensin-receptor
#8
Brian E Krumm, Sangbae Lee, Supriyo Bhattacharya, Istvan Botos, Courtney F White, Haijuan Du, Nagarajan Vaidehi, Reinhard Grisshammer
Many G protein-coupled receptors show constitutive activity, resulting in the production of a second messenger in the absence of an agonist; and naturally occurring constitutively active mutations in receptors have been implicated in diseases. To gain insight into mechanistic aspects of constitutive activity, we report here the 3.3 Å crystal structure of a constitutively active, agonist-bound neurotensin receptor (NTSR1) and molecular dynamics simulations of agonist-occupied and ligand-free receptor. Comparison with the structure of a NTSR1 variant that has little constitutive activity reveals uncoupling of the ligand-binding domain from conserved connector residues, that effect conformational changes during GPCR activation...
December 7, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27924315/control-of-selective-ion-transfer-across-liquid-liquid-interfaces-a-rectifying-heterojunction-based-on-immiscible-electrolytes
#9
Guillermo Iván Guerrero-García, Francisco J Solis, Kalyan Raidongia, Andrew Robert Koltonow, Jiaxing Huang, Mónica Olvera de la Cruz
The current rectification displayed by solid-state p-n semiconductor diodes relies on the abundance of electrons and holes near the interface between the p-n junction. In analogy to this electronic device, we propose here the construction of a purely ionic liquid-state electric rectifying heterojunction displaying an excess of monovalent cations and anions near the interface between two immiscible solvents with different dielectric properties. This system does not need any physical membrane or material barrier to show preferential ion transfer but relies on the ionic solvation energy between the two immiscible solvents...
November 23, 2016: ACS Central Science
https://www.readbyqxmd.com/read/27923803/whole-exome-sequencing-validates-a-preclinical-mouse-model-for-the-prevention-and-treatment-of-cutaneous-squamous-cell-carcinoma
#10
Elena V Knatko, Brandon Praslicka, Maureen Higgins, Alan Evans, Karin J Purdie, Catherine A Harwood, Charlotte M Proby, Aikseng Ooi, Albena T Dinkova-Kostova
Cutaneous squamous cell carcinomas (cSCC) are among the most common and highly mutated human malignancies. Solar UV radiation is the major factor in the etiology of cSCC. Whole exome sequencing of 18 microdissected tumor samples (cases) derived from SKH-1 hairless mice that had been chronically exposed to solar-simulated UV (SSUV) radiation showed a median point mutation (single nucleotide polymorphism, SNP) rate of 155 per megabase. The majority (78.6%) of the SNPs are C.G>T.A transitions, a characteristic UVR-induced mutational signature...
December 6, 2016: Cancer Prevention Research
https://www.readbyqxmd.com/read/27923633/diversity-of-glycosphingolipid-gm2-and-cholesterol-accumulation-in-npc1-patient-specific-ipsc-derived-neurons
#11
Michaela Trilck, Franziska Peter, Chaonan Zheng, Marcus Frank, Kostantin Dobrenis, Hermann Mascher, Arndt Rolfs, Moritz J Frech
Niemann-Pick disease Type C1 (NPC1) is a rare progressive neurodegenerative disorder caused by mutations in the NPC1 gene. On the cellular level NPC1 mutations lead to an accumulation of cholesterol and gangliosides. As a thorough analysis of the severely affected neuronal cells is unfeasible in NPC1 patients, we recently described the cellular phenotype of neuronal cells derived from NPC1 patient iPSCs carrying the compound heterozygous mutation c.1836A>C/c.1628delC. Here we expanded the analysis to cell lines carrying the prevalent mutation c...
December 3, 2016: Brain Research
https://www.readbyqxmd.com/read/27923328/modeling-stroma-induced-drug-resistance-in-a-tissue-engineered-tumor-model-of-ewing-sarcoma
#12
Marco Santoro, Brian A Menegaz, Salah-Eddine Lamhamedi-Cherradi, Eric R Molina, Danielle Wu, Waldemar Priebe, Joseph A Ludwig, Antonios G Mikos
Three-dimensional (3D) tumor models are gaining traction in the research community given their capacity to mimic aspects of the tumor microenvironment absent in monolayer systems. In particular, the ability to spatiotemporally control cell placement within ex vivo 3D systems has enabled the study of tumor-stroma interactions. Furthermore, by regulating biomechanical stimuli, one can reveal how biophysical cues affect stromal cell phenotype and how their phenotype impacts tumor drug sensitivity. Both tumor architecture and shear force have profound effects on Ewing sarcoma (ES) cell behavior and are known to elicit ligand-mediated activation of the insulin-like growth factor-1 receptor (IGF-1R), thereby mediating resistance of ES cells to IGF-1R inhibitors...
December 6, 2016: Tissue Engineering. Part A
https://www.readbyqxmd.com/read/27922830/ligand-receptor-binding-kinetics-in-surface-plasmon-resonance-cells-a-monte-carlo-analysis
#13
Jacob Carroll, Matthew Raum, Kimberly Forsten-Williams, Uwe C Täuber
Surface plasmon resonance (SPR) chips are widely used to measure association and dissociation rates for the binding kinetics between two species of chemicals, e.g., cell receptors and ligands. It is commonly assumed that ligands are spatially well mixed in the SPR region, and hence a mean-field rate equation description is appropriate. This approximation however ignores the spatial fluctuations as well as temporal correlations induced by multiple local rebinding events, which become prominent for slow diffusion rates and high binding affinities...
December 6, 2016: Physical Biology
https://www.readbyqxmd.com/read/27922825/model-of-turnover-kinetics-in-the-lamellipodium-implications-of-slow-and-fast-diffusing-capping-protein-and-arp2-3-complex
#14
Laura M McMillen, Dimitrios Vavylonis
Cell protrusion through polymerization of actin filaments at the leading edge of motile cells may be influenced by spatial gradients of diffuse actin and regulators. Here we study the distribution of two of the most important regulators, capping protein and Arp2/3 complex, which regulate actin polymerization in the lamellipodium through capping and nucleation of free barbed ends. We modeled their kinetics using data from prior single molecule microscopy experiments on XTC cells. These experiments have provided evidence for a broad distribution of diffusion coefficients of both capping protein and Arp2/3 complex...
December 6, 2016: Physical Biology
https://www.readbyqxmd.com/read/27922735/virtual-cell-imaging-a-review-on-simulation-methods-employed-in-image-cytometry
#15
REVIEW
Vladimír Ulman, David Svoboda, Matti Nykter, Michal Kozubek, Pekka Ruusuvuori
The simulations of cells and microscope images thereof have been used to facilitate the development, selection, and validation of image analysis algorithms employed in cytometry as well as for modeling and understanding cell structure and dynamics beyond what is visible in the eyepiece. The simulation approaches vary from simple parametric models of specific cell components-especially shapes of cells and cell nuclei-to learning-based synthesis and multi-stage simulation models for complex scenes that simultaneously visualize multiple object types and incorporate various properties of the imaged objects and laws of image formation...
December 6, 2016: Cytometry. Part A: the Journal of the International Society for Analytical Cytology
https://www.readbyqxmd.com/read/27922057/antiproliferative-activities-of-amaryllidaceae-alkaloids-from-lycoris-radiata-targeting-dna-topoisomerase-i
#16
Gui-Lin Chen, Yong-Qiang Tian, Jian-Lin Wu, Na Li, Ming-Quan Guo
Crude Amaryllidaceae alkaloids (AAs) extracted from Lycoris radiata are reported to exhibit significant anti-cancer activity. However, the specific alkaloids responsible for the pharmacodynamic activity and their targets still remain elusive. In this context, we strived to combine affinity ultrafiltration with topoisomerase I (Top I) as a target enzyme aiming to fish out specific bioactive AAs from Lycoris radiata. 11 AAs from Lycoris radiata were thus screened out, among which hippeastrine (peak 5) with the highest Enrichment factor (EF) against Top I exhibited good dose-dependent inhibition with IC50 at 7...
December 6, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27921108/a-novel-antioxidant-peptide-derived-from-wheat-germ-prevents-high-glucose-induced-oxidative-stress-in-vascular-smooth-muscle-cells-in-vitro
#17
Siyuan Chen, Dingbo Lin, Yulong Gao, Xiaozhou Cao, Xinchun Shen
The ingestion of whole wheat products is responsible for the prevention of a number of chronic diseases. The aim of this study is to characterize the molecular properties of a novel wheat germ-derived antioxidant peptide (AOP) in protection against high glucose-induced oxidative stress in vascular smooth muscle cells (VSMCs). AOP (amino acid sequence AREGETVVPG) was isolated from wheat germ albumin using dual-enzymatic hydrolysis/separation, followed by MS/MS. The in vitro IC50 value for Fe(2+) chelation was 0...
December 6, 2016: Food & Function
https://www.readbyqxmd.com/read/27921010/structural-insights-into-substrate-recognition-by-clostridium-difficile-sortase
#18
Jui-Chieh Yin, Chun-Hsien Fei, Yen-Chen Lo, Yu-Yuan Hsiao, Jyun-Cyuan Chang, Jay C Nix, Yuan-Yu Chang, Lee-Wei Yang, I-Hsiu Huang, Shuying Wang
Sortases function as cysteine transpeptidases that catalyze the covalent attachment of virulence-associated surface proteins into the cell wall peptidoglycan in Gram-positive bacteria. The substrate proteins targeted by sortase enzymes have a cell wall sorting signal (CWSS) located at the C-terminus. Up to date, it is still not well understood how sortases with structural resemblance among different classes and diverse species of bacteria achieve substrate specificity. In this study, we focus on elucidating the molecular basis for specific recognition of peptide substrate PPKTG by Clostridium difficile sortase B (Cd-SrtB)...
2016: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/27920824/cloning-expression-and-molecular-analysis-of-iranian-brucella-melitensis-omp25-gene-for-designing-a-subunit-vaccine
#19
Soheil Yousefi, Mojtaba Tahmoorespur, Mohammad Hadi Sekhavati
Brucellosis is a well-known domestic animal infectious disease, which is caused by Brucella bacterium. The outer membrane protein 25 kDa (Omp25) gene plays an important role in simulating of TNF-α, IFN-α, macrophage, and cytokines cells. In the current study molecular cloning and expression analysis of Omp25 gene for designing a subunit vaccine against Brucella was investigated. Amplifying the full length of candidate gene was performed using specific primers. Sub-cloning of this gene conducted using pTZ57R/T vector in TOP10F strain of Escherichia coli(E...
October 2016: Research in Pharmaceutical Sciences
https://www.readbyqxmd.com/read/27920524/monte-carlo-simulations-guided-by-imaging-to-predict-the-in-vitro-ranking-of-radiosensitizing-nanoparticles
#20
Paul Retif, Aurélie Reinhard, Héna Paquot, Valérie Jouan-Hureaux, Alicia Chateau, Lucie Sancey, Muriel Barberi-Heyob, Sophie Pinel, Thierry Bastogne
This article addresses the in silico-in vitro prediction issue of organometallic nanoparticles (NPs)-based radiosensitization enhancement. The goal was to carry out computational experiments to quickly identify efficient nanostructures and then to preferentially select the most promising ones for the subsequent in vivo studies. To this aim, this interdisciplinary article introduces a new theoretical Monte Carlo computational ranking method and tests it using 3 different organometallic NPs in terms of size and composition...
2016: International Journal of Nanomedicine
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