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https://www.readbyqxmd.com/read/28635276/dynamic-viscoelastic-functions-of-liquid-crystalline-chitin-nanofibril-dispersions
#1
Morihiko Yokoi, Reina Tanaka, Tsuguyuki Saito, Akira Isogai
The dynamic viscoelastic functions of aqueous chitin nanofibril (ChNF) dispersions are defined by their liquid-crystalline fibril arrangement. Four ChNF dispersions with different structures were prepared from squid-pen β-chitin, by sonication in aqueous acetic acid at pH 3 for 4‒40 min. Squid-pen β-chitin was disintegrated into randomly-oriented bundles of ChNFs during the initial stage of sonication, and then became more finely dispersed with further sonication up to 8 min. The additional sonication resulted in the individualization of the approximately 3-nm-wide ChNFs...
June 21, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28631483/amyloid-beta-peptide-folding-in-reverse-micelles
#2
Gozde Eskici, Paul H Axelsen
Previously published experimental studies have suggested that when the 40-residue amyloid beta peptide is encapsulated in a reverse micelle, it folds into a structure that may nucleate amyloid fibril formation (Yeung and Axelsen, J. Am. Chem. Soc. 134:6061, 2012). The factors that induce the formation of this structure have now been identified in a multi-microsecond simulation of the same reverse micelle system that was studied experimentally. Key features of the polypeptide-micelle interaction include the anchoring of a hydrophobic residue cluster into the reverse micelle surface, the formation of a beta turn at the anchor point that brings N- and C-terminal segments of the polypeptide into proximity, high ionic strength that promotes intramolecular hydrogen bond formation, and deformation of the reverse micelle surface to facilitate interactions with the surface along the entire length of the polypeptide...
June 20, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28631375/3d-mimicry-of-native-tissue-fiber-architecture-guides-tendon-derived-cells-and-adipose-stem-cells-into-artificial-tendon-constructs
#3
Mariana Laranjeira, Rui M A Domingues, Raquel Costa-Almeida, Rui L Reis, Manuela E Gomes
Tendon and ligament (T/L) function is intrinsically related with their unique hierarchically and anisotropically organized extracellular matrix. Their natural healing capacity is, however, limited. Here, continuous and aligned electrospun nanofiber threads (CANT) based on synthetic/natural polymer blends mechanically reinforced with cellulose nanocrystals are produced to replicate the nanoscale collagen fibrils grouped into microscale collagen fibers that compose the native T/L. CANT are then incrementally assembled into 3D hierarchical scaffolds, resulting in woven constructions, which simultaneously mimic T/L nano-to-macro architecture, nanotopography, and nonlinear biomechanical behavior...
June 20, 2017: Small
https://www.readbyqxmd.com/read/28631077/noninvasive-evaluation-of-reverse-atrial-remodeling-after-catheter-ablation-of-atrial-fibrillation-by-p-wave-dispersion
#4
Yuhi Fujimoto, Kenji Yodogawa, Kenta Takahashi, Ippei Tsuboi, Hiroshi Hayashi, Shunsuke Uetake, Yu-Ki Iwasaki, Meiso Hayashi, Yasushi Miyauchi, Wataru Shimizu
Atrial fibrillation (AF) itself creates structural and electrophysiological changes such as atrial enlargement, shortening of refractory period and decrease in conduction velocity, called "atrial remodeling", promoting its persistence. Although the remodeling process is considered to be reversible, it has not been elucidated in detail. The aim of this study was to assess the feasibility of P wave dispersion in the assessment of reverse atrial remodeling following catheter ablation of AF. Consecutive 126 patients (88 males, age 63...
June 19, 2017: Heart and Vessels
https://www.readbyqxmd.com/read/28629894/enhanced-nutrient-transport-improves-the-depth-dependent-properties-of-tri-layered-engineered-cartilage-constructs-with-zonal-co-culture-of-chondrocytes-and-mscs
#5
Minwook Kim, Megan J Farrell, David R Steinberg, Jason A Burdick, Robert L Mauck
Biomimetic design in cartilage tissue engineering is a challenge given the complexity of the native tissue. While numerous studies have generated constructs with near-native bulk properties, recapitulating the depth-dependent features of native tissue remains a challenge. Furthermore, limitations in nutrient transport and matrix accumulation in engineered constructs hinders maturation within the central core of large constructs. To overcome these limitations, we fabricated tri-layered constructs that recapitulate the depth-dependent cellular organization and functional properties of native tissue using zonally derived chondrocytes co-cultured with MSCs...
June 16, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28629861/flavonoids-determine-the-rate-of-fibrillogenesis-and-structure-of-collagen-type-i-fibrils-in-vitro
#6
Yuri A Kim, Yury S Tarahovsky, Sergei G Gaidin, Elena A Yagolnik, Eugeny N Muzafarov
Collagen fibrils are produced from collagen monomers not only in vivo, but also in vitro. The ability to have an influence on the structure and properties of fibrils may find medical application and can be useful for controlling the formation of collagen gels and sheets in tissue engineering. Here we investigated the influence of flavonoids, distinguished by the number of hydroxyl groups in the B-ring, on the formation of collagen fibrils. A correlation was found between the number of hydroxyl groups, lipophilicity of molecules and their ability to influence the fibril formation...
June 16, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28629626/left-atrial-accessory-appendages-diverticula-and-left-sided-septal-pouch-in-multi-slice-computed-tomography-association-with-atrial-fibrillation-and-cerebrovascular-accidents
#7
Mateusz K Hołda, Mateusz Koziej, Karolina Wszołek, Wiesław Pawlik, Agata Krawczyk-Ożóg, Danuta Sorysz, Piotr Łoboda, Katarzyna Kuźma, Marcin Kuniewicz, Jacek Lelakowski, Dariusz Dudek, Wiesława Klimek-Piotrowska
BACKGROUND: The aim of this study is to provide a morphometric description of the left-sided septal pouch (LSSP), left atrial accessory appendages, and diverticula using cardiac multi-slice computed tomography (MSCT) and to compare results between patient subgroups. METHODS: Two hundred and ninety four patients (42.9% females) with a mean of 69.4±13.1years of age were investigated using MSCT. The presence of the LSSP, left atrial accessory appendages, and diverticula was evaluated...
June 13, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/28628500/atrial-fibrillation-symptoms-and-sex-race-and-psychological-distress-a-literature-review
#8
Kelly T Gleason, Saman Nazarian, Cheryl R Dennison Himmelfarb
BACKGROUND: Atrial fibrillation (AF) symptoms are a major component of treatment decisions for patients with AF and impact quality of life and functional ability yet are poorly understood. OBJECTIVE: This review aimed to determine what is known about the prevalence of symptoms and the association of symptoms to AF characteristics, psychological distress, sex, and race. METHODS: We performed a structured review of AF symptoms as of March 2016 using PubMed, EMBASE, and CINAHL and reference searches of retrieved articles...
June 17, 2017: Journal of Cardiovascular Nursing
https://www.readbyqxmd.com/read/28623233/structural-and-functional-analyses-of-pyroglutamate-amyloid-%C3%AE-specific-antibodies-as-a-basis-for-alzheimer-immunotherapy
#9
Anke Piechotta, Christoph Parthier, Martin Kleinschmidt, Kathrin Gnoth, Thierry Pillot, Inge Lues, Hans-Ulrich Demuth, Stephan Schilling, Jens-Ulrich Rahfeld, Milton T Stubbs
Alzheimers disease is associated with deposition of the amyloidogenic peptide Aβ in the brain. Passive immunization using Aβ-specific antibodies has been demonstrated to reduce amyloid deposition both in vitro and in vivo. As N terminally truncated pyroglutamate (pE)-modified Aβ species (AβpE3) exhibit enhanced aggregation potential and propensity to form toxic oligomers, they represent particularly attractive targets for antibody therapy. Here we present three separate monoclonal antibodies that specifically recognize AβpE3 with affinities of 1-10 nM and inhibit AβpE3 fibril formation in vitro...
June 16, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28623034/new-nmr-tools-for-protein-structure-and-function-spin-tags-for-dynamic-nuclear-polarization-solid-state-nmr
#10
Rivkah Rogawski, Ann McDermott
Magic angle spinning solid state NMR studies of biological macromolecules [1-3] have enabled exciting studies of membrane proteins [4,5], amyloid fibrils [6], viruses, and large macromolecular assemblies [7]. Dynamic nuclear polarization (DNP) provides a means to enhance detection sensitivity for NMR, particularly for solid state NMR, with many recent biological applications and considerable contemporary efforts towards elaboration and optimization of the DNP experiment. This review explores precedents and innovations in biological DNP experiments, especially highlighting novel chemical biology approaches to introduce the radicals that serve as a source of polarization in the DNP experiments...
June 13, 2017: Archives of Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28621522/formation-and-structure-of-wild-type-huntingtin-exon-1-fibrils
#11
J Mario Isas, Andreas Langen, Myles C Isas, Nitin Kumar Pandey, Ansgar B Siemer
The fact that the heritable neurodegenerative disorder Huntington's Disease (HD) is autosomal dominant means that there is one wild type and one mutant allele in most HD patients. The CAG repeat expansion in the exon 1 of the protein huntingtin (HTTex1) that causes the disease, leads to the formation of HTT fibrils in vitro and vivo. An important question for understanding the molecular mechanism of HD is which role wild type HTT plays for the formation, propagation, and structure of these HTT fibrils. Here we report that fibrils of mutant HTTex1 are able to seed the aggregation of wild type HTTex1 into amyloid fibrils which in turn can seed the fibril formation of mutant HTTex1...
June 16, 2017: Biochemistry
https://www.readbyqxmd.com/read/28618874/von-willebrand-factor-multimeric-structure-and-functional-activity-in-patients-with-atrial-fibrillation-with-and-without-oral-anticoagulation
#12
Sandra Lopez-Castaneda, Ignacio Valencia-Hernández, Carlos Arean, Daniel Godínez-Hernández, Martha Eva Viveros-Sandoval
von Willebrand factor (vWF) is a multimeric glycoprotein present in blood plasma. It is synthesized in megakaryocytes and endothelial cells, secreted into circulation in the form of high-molecular-weight multimers (HMWMs), and cleaved into shorter, less active multimers by ADAMTS13. It is essential for platelet adhesion and aggregation. Previous studies have investigated the relationship between vWF levels and thromboembolic events with little regard to vWF multimeric structure. Patients with atrial fibrillation (AF) exhibit higher plasma vWF and lower ADAMTS13 levels...
January 1, 2017: Clinical and Applied Thrombosis/hemostasis
https://www.readbyqxmd.com/read/28617846/a-metabolite-of-leucine-%C3%AE-hydroxy-%C3%AE-methylbutyrate-given-to-sows-during-pregnancy-alters-bone-development-of-their-newborn-offspring-by-hormonal-modulation
#13
Tomasz Blicharski, Ewa Tomaszewska, Piotr Dobrowolski, Monika Hułas-Stasiak, Siemowit Muszyński
The effects of dietary β-hydroxy-β-methylbutyrate (HMB) supplementation during gestation on bone, growth plate, and articular cartilage in newborns were determined. Thermal analysis of articular cartilage was performed to examine the structural changes in collagen. At day 70 of gestation, a total of 12 sows (Large White Polish breed, at the second parity) were randomly assigned to two groups, with each group receiving either a basal diet or the same diet supplemented with 0.2 g/day HMB until the 90th day...
2017: PloS One
https://www.readbyqxmd.com/read/28614660/crystallization-temperature-dependence-of-cavitation-and-plastic-flow-in-the-tensile-deformation-of-poly-%C3%AE%C2%B5-caprolactone
#14
Zhiyong Jiang, Ran Chen, Ying Lu, Ben Whiteside, Phil D Coates, Zhonghua Wu, Yongfeng Men
In situ small-, ultrasmall-, and wide-angle X-ray scattering measurements were performed to investigate the structural evolution of crystalline lamellae and cavities as a function of deformation ratio during tensile deformation of isothermally crystallized poly(ε-caprolactone). The cavities were modelled as cylinder-shaped objects which are oriented along the stretching direction and randomly distributed in the samples, and their dimensions were evaluated by direct model fitting of scattering patterns. At small deformations, the orientation of these cavities at the onset of cavity formation was related to the isothermal crystallization temperature...
June 14, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28610723/pathophysiology-of-paroxysmal-and-persistent-atrial-fibrillation-rotors-foci-and-fibrosis
#15
REVIEW
Dennis H Lau, Dominik Linz, Ulrich Schotten, Rajiv Mahajan, Prashanthan Sanders, Jonathan M Kalman
Recent advances in our understanding of the mechanisms underlying atrial fibrillation (AF) have further underscored the complex pathophysiological basis of the arrhythmia. It has become apparent that the current clinical classification of AF does not reflect the severity of the underlying atrial disease. Atrial fibrosis has been identified as the key structural change in different substrates that are responsible for the perpetuation of AF. Three-dimensional electroanatomical mapping and late gadolinium-enhanced magnetic resonance imaging are novel modalities that can be used to facilitate identification and quantitation of atrial fibrosis for improved delineation of the AF substrate...
May 24, 2017: Heart, Lung & Circulation
https://www.readbyqxmd.com/read/28610455/non-fourier-thermal-transport-induced-structural-hierarchy-and-damage-to-collagen-ultrastructure-subjected-to-laser-irradiation
#16
Nilamani Sahoo, Arunn Narasimhan, Purbarun Dhar, Sarit Kumar Das
Comprehending the mechanism of thermal transport through biological tissues is an important factor for optimal ablation of cancerous tissues and minimising collateral tissue damage. The present study reports detailed mapping of the rise in internal temperature within the tissue mimics due to NIR (1064 nm) laser irradiation, both for bare mimics and with gold nanostructures infused. Gold nanostructures such as mesoflowers and nano spheres have been synthesized and used as photothermal converters to enhance the temperature rise, resulting in achieving the desired degradation of malignant tissue in targeted region...
June 13, 2017: International Journal of Hyperthermia
https://www.readbyqxmd.com/read/28608690/conformational-plasticity-of-the-cell-penetrating-peptide-sap-as-revealed-by-solid-state-19-f-nmr-and-circular-dichroism-spectroscopies
#17
Sergii Afonin, Vladimir Kubyshkin, Pavel K Mykhailiuk, Igor V Komarov, Anne S Ulrich
The cell-penetrating peptide SAP, which was designed as an amphipathic poly-L-proline helix II (PPII), was suggested to self-assemble into regular fibrils that are relevant for its internalization. Herein we have analyzed the structure of SAP in the membrane-bound state by solid-state (19)F-NMR, which revealed other structural states, in addition to the expected surface-aligned PPII. (2S)-2-Amino-2-[3-(trifluoromethyl)bicyclo[1.1.1]pent-1-yl]ethanoic acid and two rigid isomers of trifluoromethyl-4,5-methanoprolines (CF3-MePro) were used as labels for (19)F-NMR analysis...
June 13, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28606607/state-of-the-art-review-atrial-fibrillation-in-athletes
#18
REVIEW
M Darragh Flannery, Jonathan M Kalman, Prashanthan Sanders, André La Gerche
Exercise has substantial health benefits with pleomorphic vascular, metabolic, psychological and anti-neoplastic actions resulting in improved quality of life and longevity. Despite these many benefits, numerous studies have shown that endurance athletes are more likely to develop atrial fibrillation (AF) than non-athletes. The type, intensity and amount of sport appears to influence the risk of developing AF. Several endurance sport activities have been shown to increase the risk of developing AF but an excess in AF has not been shown in non-endurance sports...
June 3, 2017: Heart, Lung & Circulation
https://www.readbyqxmd.com/read/28605901/graphite-templated-amyloid-nanostructures-formed-by-a-potential-pentapeptide-inhibitor-for-alzheimer-s-disease-a-combined-study-of-real-time-atomic-force-microscopy-and-molecular-dynamics-simulations
#19
Na Li, Hyunbum Jang, Ming Yuan, Wanrong Li, Xiaolin Yun, Joon Lee, Qiqige Du, Ruth Nussinov, Jiahua Hou, Ratnesh Lal, Feng Zhang
Self-assembly of peptides is closely related to many diseases, including Alzheimer's, Parkinson's, and prion diseases. Understanding the basic mechanism of this assembly is essential for designing ultimate cure and preventive measures. Template-assisted self-assembly (TASA) of peptides on inorganic substrates can provide fundamental understanding of substrate-dependent peptides assemble, including the role of hydrophobic interface on the peptide fibrillization. Here, we have studied the self-assembly process of a potential pentapeptide inhibitor on the surface of highly oriented pyrolytic graphite (HOPG) using real time atomic force microscopy (RT-AFM) as well as molecular dynamics (MD) simulation...
June 12, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28605437/anatomical-predisposing-factors-of-transmural-thermal-injury-after-pulmonary-vein-isolation
#20
Takashi Kaneshiro, Yoshiyuki Matsumoto, Minoru Nodera, Masashi Kamioka, Yoshiyuki Kamiyama, Akiomi Yoshihisa, Hiroshi Ohkawara, Hitoshi Suzuki, Yasuchika Takeishi
Aims: Transmural thermal injury (TTI), such as oesophageal erosion/ulcer and perioesophageal nerve injury leading to gastric hypomotility, is an important complication associated with pulmonary vein isolation (PVI). However, a predictor of TTI concerning anatomical structures surrounding the oesophagus has not yet been fully elucidated. Therefore, we sought to identify the predisposing factors of TTI after PVI. Methods: Consecutive 110 patients, who underwent PVI for atrial fibrillation, received oesophagogastroduodenoscopy 2 days later, were investigated...
June 12, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
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