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https://www.readbyqxmd.com/read/27926842/intact-telopeptides-enhance-interactions-between-collagens
#1
Marjan Shayegan, Tuba Altindal, Evan Kiefl, Nancy R Forde
Collagen is the fundamental structural component of a wide range of connective tissues and of the extracellular matrix. It undergoes self-assembly from individual triple-helical proteins into well-ordered fibrils, a process that is key to tissue development and homeostasis, and to processes such as wound healing. Nucleation of this assembly is known to be slowed considerably by pepsin removal of short nonhelical regions that flank collagen's triple helix, known as telopeptides. Using optical tweezers to perform microrheology measurements, we explored the changes in viscoelasticity of solutions of collagen with and without intact telopeptides...
December 6, 2016: Biophysical Journal
https://www.readbyqxmd.com/read/27926839/circular-dichroism-spectroscopy-of-collagen-fibrillogenesis-a-new-use-for-an-old-technique
#2
Kathryn E Drzewiecki, Daniel R Grisham, Avanish S Parmar, Vikas Nanda, David I Shreiber
Type-I collagen assembles in a stepwise, hierarchic fashion from the folding of the triple helix to the assembly of fibrils into fibers. The mature assembled fibers are crucial for tissue structure and mechanics, cell interactions, and other functions in vivo. Although triple helix folding can be followed with the use of optical methods such as circular dichroism (CD) spectroscopy, fibrillogenesis is typically measured by alternative methods such as turbidity, rheology, and microscopy. Together, these approaches allow for investigation of the mechanical properties and architectures of collagen-based scaffolds and excised tissues...
December 6, 2016: Biophysical Journal
https://www.readbyqxmd.com/read/27923619/synthesis-and-application-of-%C3%AE-carbolines-as-novel-multi-functional-anti-alzheimer-s-disease-agents
#3
William Horton, Abha Sood, Swarada Peerannawar, Nandor Kugyela, Aditya Kulkarni, Rekha Tulsan, Chris D Tran, Jessica Soule, Harry LeVine, Béla Török, Marianna Török
The design, synthesis and assessment of β-carboline core-based compounds as potential multifunctional agents against several processes that are believed to play a significant role in Alzheimer's disease (AD) pathology, are described. The activity of the compounds was determined in Aβ self-assembly (fibril and oligomer formation) and cholinesterase (AChE, BuChE) activity inhibition, and their antioxidant properties were also assessed. To obtain insight into the mode of action of the compounds, HR-MS studies were carried out on the inhibitor-Aβ complex formation and molecular docking was performed on inhibitor-BuChE interactions...
November 24, 2016: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/27923400/allele-specific-expression-in-the-human-heart-and-its-application-to-postoperative-atrial-fibrillation-and-myocardial-ischemia
#4
Martin I Sigurdsson, Louis Saddic, Mahyar Heydarpour, Tzuu-Wang Chang, Prem Shekar, Sary Aranki, Gregory S Couper, Stanton K Shernan, Jon G Seidman, Simon C Body, Jochen D Muehlschlegel
BACKGROUND: Allele-specific expression (ASE) is differential expression of each of the two chromosomal alleles of an autosomal gene. We assessed ASE patterns in the human left atrium (LA, n = 62) and paired samples from the left ventricle (LV, n = 76) before and after ischemia, and tested the utility of differential ASE to identify genes associated with postoperative atrial fibrillation (poAF) and myocardial ischemia. METHODS: Following genotyping from whole blood and whole-genome sequencing of LA and LV samples, we called ASE using sequences overlapping heterozygous SNPs using rigorous quality control to minimize false ASE calling...
December 6, 2016: Genome Medicine
https://www.readbyqxmd.com/read/27922050/identification-and-structural-characterization-of-the-n-terminal-amyloid-core-of-orb2-isoform-a
#5
Silvia A Cervantes, Thalia H Bajakian, Maria A Soria, Alexander S Falk, Rachel J Service, Ralf Langen, Ansgar B Siemer
Orb2 is a functional amyloid that plays a key role in Drosophila long-term memory formation. Orb2 has two isoforms that differ in their N-termini. The N-terminus of the A isoform (Orb2A) that precedes its Q-rich prion-like domain has been shown to be important for Orb2 aggregation and long-term memory. However, besides the fact that it forms fibrillar aggregates, structural information of Orb2 is largely absent. To understand the importance of the N-terminus of Orb2A and its relation to the fibril core, we recorded solid-state NMR and EPR data on fibrils formed by the first 88 residues of Orb2A (Orb2A88)...
December 6, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27921029/nanoscale-structure-and-spectroscopic-probing-of-a%C3%AE-1-40-fibril-bundle-formation
#6
Katarzyna M Psonka-Antonczyk, Per Hammarström, Leif B G Johansson, Mikael Lindgren, Bjørn T Stokke, K Peter R Nilsson, Sofie Nyström
Amyloid plaques composed of fibrillar Amyloid-β (Aβ) are hallmarks of Alzheimer's disease. However, Aβ fibrils are morphologically heterogeneous. Conformation sensitive luminescent conjugated oligothiophenes (LCOs) are versatile tools for monitoring such fibril polymorphism in vivo and in vitro. Biophysical methods applied on in vitro generated Aβ fibrils, stained with LCOs with different binding and fluorescence properties, can be used to characterize the Aβ fibrillation in depth, far beyond that possible for in vivo generated amyloid plaques...
2016: Frontiers in Chemistry
https://www.readbyqxmd.com/read/27919808/attenuation-of-amyloid-fibrillation-in-presence-of-warfarin-a-biophysical-investigation
#7
Mohammad Khursheed Siddiqi, Parvez Alam, Sumit Kumar Chaturvedi, Saima Nusrat, Yasser E Shahein, Rizwan Hasan Khan
Protein misfolding and aggregation are associated with more than twenty diseases, such as neurodegenerative diseases. The amyloid oligomers and fibrils may induce cell membrane disruption and lead to cell apoptosis. A great number of studies have focused on discovery of amyloid inhibitors which may prevent or treat amyloidosis. In this study, we used human serum albumin (HSA) as an amyloid model to test the anti-amyloid effects of warfarin (WFN), a very well-known drug for treatment of thrombosis and also used by biophysicists to characterize the specific binding site on HSA (site I of subdomain IIA)...
December 2, 2016: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/27918043/thermoresponsive-structured-emulsions-based-on-the-fibrillar-self-assembly-of-natural-saponin-glycyrrhizic-acid
#8
Zhili Wan, Yingen Sun, Lulu Ma, Jian Guo, Jinmei Wang, Shouwei Yin, Xiaoquan Yang
We report the novel use of the naturally occurring saponin, glycyrrhizic acid (GA) as a structuring material to transform liquid oil into a soft-solid structured emulsion system. The GA nanofibrils from the anisotropic self-assembly of GA molecules were first used as stabilizers to fabricate olive oil-in-water emulsions using a facile one-step emulsification at high temperature. Then, the obtained emulsions were further self-organized into the emulsion gel by applying a subsequent cooling to trigger the gel network formation, which is mostly due to the enhanced noncovalent interactions among GA fibrils in the continuous phase as well as at the droplet surface...
December 5, 2016: Food & Function
https://www.readbyqxmd.com/read/27916812/synthesis-and-structure-activity-relationships-of-a-series-of-aporphine-derivatives-with-antiarrhythmic-activities-and-acute-toxicity
#9
Hui Wang, Xin Cheng, Shujun Kong, Zixian Yang, Hongmei Wang, Qiuyan Huang, Jingyu Li, Cheng Chen, Yunshu Ma
Some aporphine alkaloids, such as crebanine, were found to present arrhythmic activity and also higher toxicity. A series of derivatives were synthesized by using three kinds of aporphine alkaloids (crebanine, isocorydine, and stephanine) as lead compounds. Chemical methods, including ring-opening reaction, bromination, methylation, acetylation, quaternization, and dehydrogenation, were adopted. Nineteen target derivatives were evaluated for their antiarrhythmic potential in the mouse model of ventricular fibrillation (VF), induced by CHCl₃, and five of the derivatives were investigated further in the rat model of arrhythmia, induced by BaCl₂...
November 28, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/27916677/differential-copper-binding-to-alpha-synuclein-and-its-disease-associated-mutants-affect-the-aggregation-and-amyloid-formation
#10
Priyatosh Ranjan, Dhiman Ghosh, Deepthi S Yarramala, Subhadeep Das, Samir K Maji, Ashutosh Kumar
BACKGROUND: Copper is an essential trace element required for the proper functioning of various enzymes present in central nervous system. An imbalance in the copper homeostasis results in the pathology of various neurogenerative disorders including Parkinson's Disease. Hence, residue specific interaction of Cu(2+) to α-Syn along with the familial mutants H50Q and G51D needs to be studied in detail. METHODS: We investigated the residue specific mapping of Cu(2+) binding sites and binding strength using solution-state NMR and ITC respectively...
December 1, 2016: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/27911039/para-sulfonato-calix-n-arenes-inhibit-amyloid-beta-peptide-fibrillation-and-reduce-amyloid-cytotoxicity
#11
Ziyuan Wang, Shipeng Tao, Xiaoyan Dong, Yan Sun
Amyloid β-peptides (Aβ) fibrillation is a major hallmark of Alzheimer's disease (AD). Inhibition of Aβ fibrillation is thus considered as an effective strategy for AD prevention and treatment. Here we show that para-sulfonato-calix[n]arenes (SC[n]A, n=4, 6, 8), a class of amphiphilic calixarene derivatives, can bind to Aβ42 through nonspecific and multipoint hydrophobic interactions. Their binding leads to a pronounced delay in β-sheet adoption and formation of multiple secondary structures of the peptide, accompanied by changes at the level of the fibrillary architecture...
December 2, 2016: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/27909516/the-role-of-noacs-in-atrial-fibrillation-management-a-qualitative-study
#12
Katherine Kirley Md Ms, Goutham Rao Md, Victoria Bauer Bs, Christopher Masi Md PhD
Patients with atrial fibrillation (AF) benefit from anticoagulation to reduce stroke risk. However, 30-60% of patients with AF are not anticoagulated. This study explored physicians' reasons for under-treatment of AF, focusing on the role of the novel oral anticoagulants (NOACs). We interviewed primary care physicians and cardiologists involved in AF management in a variety of practice settings. We conducted interviews using a semi-structured format and analyzed the data using the Framework Method. Four themes emerged...
June 2016: Journal of Atrial Fibrillation
https://www.readbyqxmd.com/read/27909515/myocardial-biopsy-in-idiopathic%C3%A2-atrial-fibrillation-and-other-arrhythmias-nosological-diagnosis-clinical-and-morphological-parallels-and-treatment
#13
O V Blagova, A V Nedostup, E A Kogan, V A Sulimov, S A Abugov, A G Kupriyanova, V A Zaydenov, A E Donnikov, E V Zaklyazminskaya, E A Okisheva
BACKGROUND: The nosological nature of "idiopathic" arrhythmias and the effect of etiotropic and pathogenetic treatment are often unknown. METHODS AND RESULTS: 19 patients (42.6±11.3 years, 9 women) with atrial fibrillation (n = 16), supraventricular (n = 10) and ventricular (n = 4) premature beats, supraventricular (n = 2) and ventricular tachycardia (n = 1), left bundle branch block (n= 2), AV block (n = 2) without structural heart changes. Viruses were identified (polymerase chain reaction, PCR) along with measurement of anti-heart antibodies (AHA) and endomyocardial biopsy (EMB)...
June 2016: Journal of Atrial Fibrillation
https://www.readbyqxmd.com/read/27909505/malignancy-associated-iatrogenic-iliopsoas-abscess-venous-access-complication-from-ablation-procedure
#14
Sandia Iskandar Md, Moustapha Atoui Md, Muhammad Rizwan Afzal Md, Madhav Lavu Md, Madhu Reddy Md, Dhanunjaya Lakkireddy Md
Iliopsoas abscess is a rare condition with a high rate of mortality and morbidity if left untreated. It can occur from hematogenous or lymphatic spread from distant structures or as a result of contiguous spread from adjacent structures. The disease typically occurs in patients with immunocompromised status and the symptoms can be non-specific.1,2 Generally, infectious complications from venous access during atrial fibrillation (AF) procedure are uncommon, and an iatrogenic iliopsoas abscess from percutaneous cardiac procedures has never been reported...
April 2016: Journal of Atrial Fibrillation
https://www.readbyqxmd.com/read/27909503/first-and-second-generation-cryoballoon-ablation-efficacy-restoring-and-maintaining-sinus-rhythm-in-patients-electrically-selected-and-treated-for-long-standing-persistent-atrial-fibrillation-after-acute-complete-electrical-disconnection-of-pulmonary-veins
#15
Jesus M Paylos Md PhD, Luis Azcona Md, Lourdes Lacal Md, Marisol Paradela Md, Carmen Cilleros Md, Ildefonso Del Campo Md, Clara Ferrero Rn Carlos Martínez Md PhD, Aracelis Morales Md
Introduction Cryoballoon ablation (CB) has proven effective to treatment of patients (pts) with atrial fibrillation (AF). However, the isolated efficacy of CB to treat pts with long-standing persistent atrial fibrillation (LSPAF) is less know. We analyzed the acute results and the long-term follow-up of our pts suffering LSPAF and initially treated with CB. Methods A cohort of 44 pts, 37 male (84%) mean age (60±10 year) suffering LSPAF were treated with first (CB1): 15pts, and second (CB2): 29 pts, generation CB...
April 2016: Journal of Atrial Fibrillation
https://www.readbyqxmd.com/read/27909493/antiarrhythmic-effect-of-antioxidants-in-patients-with-atrial-fibrillation
#16
Rustam Khabchabov PhD, Khabchabov Rg PhD, Makhmudova Er PhD
Resume In accordance with modern concepts, one of the leading roles in the development of paroxysmal atrial fibrillation and flutter, belongs - the restructuring of the myocardium, in second place - sick sinus syndrome and in third place - the presence of accessory pathways and hormonal disorders. The development of atrial fibrillation and flutter in the structural pathology, primarily begins with of drugs if it does not work, we have to carry out ablation. Providing proper, effective and important combination therapy - is the main challenge in cardiology...
April 2016: Journal of Atrial Fibrillation
https://www.readbyqxmd.com/read/27909479/atrial-fibrillation-ablation-in-adults-with-repaired-congenital-heart-disease
#17
REVIEW
Marta Acena Md, Ignasi Anguera Md PhD, Paolo D Dallaglio Md, Marcos Rodriguez Md, Xavier Sabaté Md PhD
The incidence of atrial fibrillation (AF) in congenital heart disease (CHD) adults has increased in the past decades due to a longer life expectancy of this population where the subjects are exposed to cardiac overflow, overpressure and structural changes for years. The literature regarding AF ablation in repaired CHD adults emphasizes the importance of intracardiac echocardiography (ICE) to perform the transseptal puncture and the ablation procedure in the left atrium (LA), both effectively and safely. In small case control studies, where the predominant congenital cardiomyopathy was the atrial septal defect, the most common strategy for ablation was antral isolation of the pulmonary veins showing results, at one year follow-up, similar to those in the general population...
February 2016: Journal of Atrial Fibrillation
https://www.readbyqxmd.com/read/27909052/spontaneous-unfolding-refolding-of-fibronectin-type-iii-domains-assayed-by-thiol-exchange-thermodynamic-stability-correlates-with-rates-of-unfolding-rather-than-folding
#18
Riddhi Shah, Tomoo Ohashi, Harold P Erickson, Terrence G Oas
Globular proteins are not permanently folded, but spontaneously unfold and refold on time scales that can span orders of magnitudes for different proteins. A long-standing debate in the protein-folding field is whether unfolding rates or folding rates correlate to the stability of a protein. In the present study we have determined the unfolding and folding kinetics of ten FNIII domains. FNIII domains are one of the most common protein folds, and are present in 2% of animal proteins. FNIII domains are ideal for this study because they have an identical 7-strand beta sandwich structure, but they vary widely in sequence and thermodynamic stability...
November 30, 2016: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/27908114/self-consistent-implementation-of-meta-gga-functionals-for-the-onetep-linear-scaling-electronic-structure-package
#19
James C Womack, Narbe Mardirossian, Martin Head-Gordon, Chris-Kriton Skylaris
Accurate and computationally efficient exchange-correlation functionals are critical to the successful application of linear-scaling density functional theory (DFT). Local and semi-local functionals of the density are naturally compatible with linear-scaling approaches, having a general form which assumes the locality of electronic interactions and which can be efficiently evaluated by numerical quadrature. Presently, the most sophisticated and flexible semi-local functionals are members of the meta-generalized-gradient approximation (meta-GGA) family, and depend upon the kinetic energy density, τ, in addition to the charge density and its gradient...
November 28, 2016: Journal of Chemical Physics
https://www.readbyqxmd.com/read/27907904/a-new-cryoenergy-for-ventricular-tachycardia-ablation-a-proof-of-concept-study
#20
Benjamin Berte, Frédéric Sacher, Jean-Yves Wielandts, Saagar Mahida, Xavier Pillois, Rukshen Weerasooriya, Olivier Bernus, Pierre Jaïs
INTRODUCTION: Lack of transmural lesion formation during radiofrequency (RF) ablation for ventricular tachycardia (VT) is an important determinant of arrhythmia recurrence. The aim of this proof-of-concept study was to evaluate safety and efficacy of a new and more powerful cryoablation system for ventricular ablation. METHODS AND RESULTS: Five healthy female sheep (59 ± 6 kg) underwent a surgical sternotomy for epicardial and endocardial access [endocardial access via right atrial appendage and left ventricular (LV) apex]...
October 25, 2016: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
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