Read by QxMD icon Read

fibril structure

Angelica Nakagawa Lima, Ronaldo Junio de Oliveira, Antônio Sérgio Kimus Braz, Maurício Garcia de Souza Costa, David Perahia, Luis Paulo Barbour Scott
There are two different prion conformations: (1) the cellular natural (PrPC ) and (2) the scrapie (PrPSc ), an infectious form that tends to aggregate under specific conditions. PrPC and PrPSc are widely different regarding secondary and tertiary structures. PrPSc contains more and longer β-strands compared to PrPC . The lack of solved PrPSc structures precludes a proper understanding of the mechanisms related to the transition between cellular and scrapie forms, as well as the aggregation process. In order to investigate the conformational transition between PrPC and PrPSc , we applied MDeNM (molecular dynamics with excited normal modes), an enhanced sampling simulation technique that has been recently developed to probe large structural changes...
March 15, 2018: European Biophysics Journal: EBJ
Natalia A Trayanova, Patrick M Boyle, Plamen P Nikolov
The goal of this article is to review advances in computational modeling of the heart, with a focus on recent non-invasive clinical imaging- and simulation-based strategies aimed at improving the diagnosis and treatment of patients with arrhythmias and structural heart disease. Following a brief overview of the field of computational cardiology, we present recent applications of the personalized virtual-heart approach in predicting the optimal targets for infarct-related ventricular tachycardia and atrial fibrillation ablation, and in determining risk of sudden cardiac death in myocardial infarction patients...
March 2018: Current Opinion in Biomedical Engineering
Niloy Kundu, Debasis Banik, Nilmoni Sarkar
Amphiphiles are class of molecules which are known to assemble into a variety of nanostructures. The understanding and applications of self-assembled systems are based on what has been learned from biology. Among the vast number of self-assemblies, in this article, we have described the formation, characterization and dynamics of two important biologically inspired assemblies, vesicles and fibrils. Vesicles, which can be classified into several categories depending on the sizes and components, are of great interest due to their potential application in drug delivery and as nanoscale reactor...
March 15, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Dominik Linz, R Doug McEvoy, Martin R Cowie, Virend K Somers, Stanley Nattel, Patrick Lévy, Jonathan M Kalman, Prashanthan Sanders
Importance: Obstructive sleep apnea (OSA) is the most common clinically significant breathing abnormality during sleep. It is highly prevalent among patients with atrial fibrillation (AF), and it promotes arrhythmogenesis and impairs treatment efficacy. Observations: The prevalence of OSA ranges from 3% to 49% in population-based studies and from 21% to 74% in patients with AF. Diagnosis and treatment of OSA in patients with AF requires a close interdisciplinary collaboration between electrophysiologists, cardiologists, and sleep specialists...
March 14, 2018: JAMA Cardiology
Kathryn E Drzewiecki, Juilee N Malavade, Ijaz Ahmed, Christopher J Lowe, David I Shreiber
As a biomaterial, collagen has been used throughout tissue engineering and regenerative medicine. Collagen is native to the body, is highly biocompatible, and naturally promotes cell adhesion and regeneration. However, collagen fibers and the inherent weak mechanical properties of collagen hydrogels interfere with further development of collagen as a bio-ink. Herein, we demonstrate the use of a modified type-I collagen, collagen methacrylamide (CMA), as a fibril-forming bio-ink for free-form fabrication of scaffolds...
December 2017: Technology
Ariel A Valiente-Gabioud, Dietmar Riedel, Tiago F Outeiro, Mauricio A Menacho-Márquez, Christian Griesinger, Claudio O Fernández
The inherent tendency of proteins to convert from their native states into amyloid aggregates is associated with a range of human disorders, including Alzheimer's and Parkinson's diseases. In that sense, the use of small molecules as probes for the structural and toxic mechanism related to amyloid aggregation has become an active area of research. Compared with other compounds, the structural and molecular basis behind the inhibitory interaction of phthalocyanine tetrasulfonate (PcTS) with proteins such as αS and tau has been well established, contributing to a better understanding of the amyloid aggregation process in these proteins...
March 13, 2018: Biophysical Journal
Hein Heidbuchel, Nikolaos Dagres, Matthias Antz, Karl-Heinz Kuck, Patrice Lazure, Suzanne Murray, Céline Carrera, Gerhard Hindricks, Alec Vahanian
Aims: Guideline-adherent treatment is associated with improved prognosis in atrial fibrillation (AF) patients but is insufficiently implemented in clinical practice. The European Society of Cardiology (ESC) performed a multinational educational needs assessment study among cardiologists, general practitioners/family physicians (GPs/FPs), and neurologists in order to evaluate knowledge and skills of physicians and system factors related to AF care delivery. Methods and results: A total of 561 physicians (294 cardiologists, 131 neurologists, and 136 GPs/FPs) from six European countries participated...
March 12, 2018: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
Rui Zhang, Qianlei Zhang, Youxin Ji, Fengmei Su, Lingpu Meng, Zeming Qi, Yuanfei Lin, Xueyu Li, Xiaowei Chen, Fei Lv, Liangbin Li
Fibrillation and the complexation reaction between poly(vinyl alcohol) (PVA)-iodine (i) complexes have been studied with in situ synchrotron radiation small- and wide-angle X-ray scattering (SAXS and WAXS) during the uniaxial stretching of PVA films in KI/I2 aqueous solution. SAXS results show that stretching induces the formation of nanofibrils, which pack periodically in the later stage of stretching with an average inter-fibrillar distance of around 10 nm. The onset strains for fibrillation and the appearance of periodicity of nanofibrils are located at the beginning and the end of the stress plateau, and decrease with increasing iodine concentration...
March 14, 2018: Soft Matter
Xiaocui Fang, Maryam Yousaf, Qunxing Huang, Yanlian Yang, Chen Wang
The oligomerization and fibrillation of human islet amyloid polypeptide (hIAPP) play a central role in the pathogenesis of type 2 diabetes. Strategies for remodelling the formation of hIAPP oligomers and fibrils have promising application potential in type 2 diabetes therapy. Herein, we demonstrated that PEG-PE micelle could inhibit hIAPP oligomerization and fibrillation through blocking the hydrophobic interaction and the conformational change from random coil to β-sheet structures of hIAPP. In addition, we also found that PEG-PE micelle could remodel the preformed hIAPP fibrils allowing the formation of short fibrils and co-aggregates...
March 13, 2018: Scientific Reports
Andrew S Quigley, Stéphane Bancelin, Dylan Deska-Gauthier, François Légaré, Laurent Kreplak, Samuel P Veres
The collagen-based tissues of animals are hierarchical structures: even tendon, the simplest collagenous tissue, has seven to eight levels of hierarchy. Tailoring tissue structure to match physiological function can occur at many different levels. We wanted to know if the control of tissue architecture to achieve function extends down to the nanoscale level of the individual, cable-like collagen fibrils. Using tendons from young adult bovine forelimbs, we performed stress-strain experiments on single collagen fibrils extracted from tendons with positional function, and tendons with energy storing function...
March 13, 2018: Scientific Reports
Shiwei Huang, Binglin Pan, He Zou, Wei Lin
BACKGROUND: Atrial fibrillation (AF) usually originates from pulmonary veins (PVs) but can also be caused by pulmonary veins outside, such as the coronary sinus (CS), the superior vena cava (SVC), and the ligament of Marshall. CASE PRESENTATION: A 69-year-old male with a history of palpitations for 10 years was referred to our institute because of its recurrence for half a day. A dynamic electrocardiogram revealed sinus rhythm (SR) and paroxysmal AF. Echocardiography demonstrated normal cardiac structure, and physical examination results were unremarkable...
March 13, 2018: BMC Cardiovascular Disorders
Xue-Jiao Ma, Yin-Juan Zhang, Cheng-Ming Zeng
Sodium dodecyl sulfate (SDS), as an anionic surfactant, can induce protein conformational changes. Recent investigations demonstrated different effects of SDS on protein amyloid aggregation. In the present study, the effect of SDS on amyloid aggregation of bovine serum albumin (BSA) was evaluated. BSA transformed to β-sheet-rich amyloid aggregates upon incubation at pH 7.4 and 65°C, as demonstrated by thioflavin T fluorescence, circular dichroism, and transmission electron microscopy. SDS at submicellar concentrations inhibited BSA amyloid aggregation with IC50 of 47...
January 2018: Biochemistry. Biokhimii︠a︡
Elizabeth L Guenther, Peng Ge, Hamilton Trinh, Michael R Sawaya, Duilio Cascio, David R Boyer, Tamir Gonen, Z Hong Zhou, David S Eisenberg
Proteins in the fibrous amyloid state are a major hallmark of neurodegenerative disease. Understanding the multiple conformations, or polymorphs, of amyloid proteins at the molecular level is a challenge of amyloid research. Here, we detail the wide range of polymorphs formed by a segment of human TAR DNA-binding protein 43 (TDP-43) as a model for the polymorphic capabilities of pathological amyloid aggregation. Using X-ray diffraction, microelectron diffraction (MicroED) and single-particle cryo-EM, we show that the247 DLIIKGISVHI257 segment from the second RNA-recognition motif (RRM2) forms an array of amyloid polymorphs...
March 12, 2018: Nature Structural & Molecular Biology
Jatish Kumar, Hasier Eraña, Elena López-Martínez, Nathalie Claes, Víctor F Martín, Diego M Solís, Sara Bals, Aitziber L Cortajarena, Joaquín Castilla, Luis M Liz-Marzán
Amyloid fibrils, which are closely associated with various neurodegenerative diseases, are the final products in many protein aggregation pathways. The identification of fibrils at low concentration is, therefore, pivotal in disease diagnosis and development of therapeutic strategies. We report a methodology for the specific identification of amyloid fibrils using chiroptical effects in plasmonic nanoparticles. The formation of amyloid fibrils based on α-synuclein was probed using gold nanorods, which showed no apparent interaction with monomeric proteins but effective adsorption onto fibril structures via noncovalent interactions...
March 12, 2018: Proceedings of the National Academy of Sciences of the United States of America
Anne Diehl, Yvette Roske, Linda Ball, Anup Chowdhury, Matthias Hiller, Noel Molière, Regina Kramer, Daniel Stöppler, Catherine L Worth, Brigitte Schlegel, Martina Leidert, Nils Cremer, Natalja Erdmann, Daniel Lopez, Heike Stephanowitz, Eberhard Krause, Barth-Jan van Rossum, Peter Schmieder, Udo Heinemann, Kürşad Turgay, Ümit Akbey, Hartmut Oschkinat
Microorganisms form surface-attached communities, termed biofilms, which can serve as protection against host immune reactions or antibiotics. Bacillus subtilis biofilms contain TasA as major proteinaceous component in addition to exopolysaccharides. In stark contrast to the initially unfolded biofilm proteins of other bacteria, TasA is a soluble, stably folded monomer, whose structure we have determined by X-ray crystallography. Subsequently, we characterized in vitro different oligomeric forms of TasA by NMR, EM, X-ray diffraction, and analytical ultracentrifugation (AUC) experiments...
March 12, 2018: Proceedings of the National Academy of Sciences of the United States of America
Fabian Plank, Christoph Beyer, Guy Friedrich, Markus Stühlinger, Florian Hintringer, Wolfgang Dichtl, Matthias Wildauer, Gudrun Feuchtner
OBJECTIVE: Vitamin K antagonists (VKA) are associated with increased vascular calcification which may lead to an elevated cardiovascular risk. If the direct anticoagulants (DOACs) have similar negative vascular effects is unknown. We evaluated the influence of different anticoagulation strategies on coronary artery disease (CAD) using coronary computed tomography angiography (CTA). METHODS: Overall 702 consecutive patients with non-valvular atrial fibrillation (AF) who underwent CTA for AF ablation planning were enrolled and stratified according to their anticoagulation into VKA, DOAC (all agents) and a control group without oral anticoagulation...
March 6, 2018: International Journal of Cardiology
Patrycja Pruszkowska, Radosław Lenarczyk, Jakub Gumprecht, Ewa Jedrzejczyk-Patej, Michał Mazurek, Oskar Kowalski, Adam Sokal, Tomasz Podolecki, Stanisław Morawski, Witold Streb, Katarzyna Mitręga, Zbigniew Kalarus
BACKGROUND: Pulmonary vein isolation with cryobaloon catheter ablation (CCB) is an effective method oftreatment in patients with atrial fibrillation (AF) but in patients with heart failure (HF) therole of CCB remains unknown. AIMS: To assess feasibility, effectiveness and safety of CCB in patients with HF and cardiac electronic devices (CIED), the impact of the procedure on symptoms and echocardiographic parameters. METHODS: Thirty consecutive HF patients with left ventricular ejection fraction (EF)≤40% and CIED, referred for CCB of AF were included...
March 12, 2018: Kardiologia Polska
Therese W Herling, Aviad Levin, Kadi L Saar, Christopher M Dobson, Tuomas P J Knowles
The self-assembly of proteins into supramolecular structures and machinery underpins biological activity in living systems. Misassembled, misfolded and aggregated protein structures can, by contrast, have deleterious activity and such species are at the origin of a number of disease states ranging from cancer to neurodegenerative disorders. In particular, the formation of highly ordered protein aggregates, amyloid fibrils, from normally soluble peptides and proteins, is the common pathological hallmark of a range a group of over fifty protein misfolding disorders...
March 12, 2018: Lab on a Chip
Vijayaraghavan Rangachari, Dexter N Dean, Pratip Rana, Ashwin Vaidya, Preetam Ghosh
Self-templating propagation of protein aggregate conformations is increasingly becoming a significant factor in many neurological diseases. In Alzheimer disease (AD), intrinsically disordered amyloid-β (Aβ) peptides undergo aggregation that is sensitive to environmental conditions. High-molecular weight aggregates of Aβ that form insoluble fibrils are deposited as senile plaques in AD brains. However, low-molecular weight aggregates called soluble oligomers are known to be the primary toxic agents responsible for neuronal dysfunction...
March 8, 2018: Biochimica et Biophysica Acta
Nicholas Y Tan, Omar Z Yasin, Alan Sugrue, Abdallah El Sabbagh, Thomas A Foley, Samuel J Asirvatham
The left atrial appendage has been implicated as a major nidus for thrombus formation, particularly in atrial fibrillation. This discovery has prompted substantial interest in the development of left atrial appendage exclusion devices aimed at decreasing systemic thromboembolism risk. Its deceptively simple appearance belies the remarkable complexity that characterizes its anatomy and physiology. We highlight the key anatomic features and variations of the left atrial appendage as well as its relationships with surrounding structures...
April 2018: Interventional Cardiology Clinics
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"