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Mechanical Valve

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https://www.readbyqxmd.com/read/28102868/control-and-automation-of-multilayered-integrated-microfluidic-device-fabrication
#1
Sarit Kipper, Ludmila Frolov, Ortal Guy, Michal Pellach, Yair Glick, Asaf Malichi, Binyamin A Knisbacher, Efrat Barbiro-Michaely, Dorit Avrahami, Yehuda Yavets-Chen, Erez Y Levanon, Doron Gerber
Integrated microfluidics is a sophisticated three-dimensional (multi layer) solution for high complexity serial or parallel processes. Fabrication of integrated microfluidic devices requires soft lithography and the stacking of thin-patterned PDMS layers. Precise layer alignment and bonding is crucial. There are no previously reported standards for alignment of the layers, which is mostly performed using uncontrolled processes with very low alignment success. As a result, integrated microfluidics is mostly used in academia rather than in the many potential industrial applications...
January 19, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28102784/model-systems-for-the-study-of-enterococcal-colonization-and-infection
#2
H M Sharon Goh, M H Adeline Yong, Kelvin Kian Long Chong, Kimberly A Kline
Enterococcus faecalis and Enterococcus faecium are common inhabitants of the human gastrointestinal tract, as well as frequent opportunistic pathogens. Enterococci cause a range of infections including, most frequently, infections of the urinary tract, catheterized urinary tract, bloodstream, wounds and surgical sites, and heart valves in endocarditis. Enterococcal infections are often biofilm-associated, polymicrobial in nature, and resistant to antibiotics of last resort. Understanding Enterococcal mechanisms of colonization and pathogenesis are important for identifying new ways to manage and intervene with these infections...
January 19, 2017: Virulence
https://www.readbyqxmd.com/read/28097199/long-term-survival-after-composite-mechanical-aortic-root-replacement
#3
Khaled E Al-Ebrahim, Husain H Jabbad, Ahmad H Alqari
This report describes the long-term follow-up of the repair of a giant ascending aneurysm using a composite graft with a mechanical valve.
August 2016: Aorta (Stamford, Conn.)
https://www.readbyqxmd.com/read/28097190/chronic-type-a-aortic-dissection-and-giant-aortic-root-aneurysm-after-aortic-valve-replacement
#4
Andrés Enríquez Puga, Sara Castaño Rodríguez, Blanca Mateos Pañero, Beatriz Castaño Moreira, Luis Fernando López Almodóvar
We describe the case of a 61-year-old male with a giant aortic root aneurysm associated with chronic aortic Type A dissection. The patient had been operated on 16 years before due to aortic annuloectasia with mechanical valve replacement. The patient underwent revision aortic surgery with a Bentall-De Bono operation with Svensson modification, using a #21 On-X Valsalva mechanical valve conduit. The postoperative course was uneventful.
June 2016: Aorta (Stamford, Conn.)
https://www.readbyqxmd.com/read/28094176/atrial-septal-defect-in-a-patient-with-a-mechanical-mitral-valve-prosthesis-undergoing-implantation-of-a-left-ventricular-assist-device-to-repair-or-not-to-repair
#5
Michael Essandoh, Bryan Whitson, Luke Dong, Ashley Yager, Ashley Gabrielsen, Ahmet Kilic
No abstract text is available yet for this article.
November 2, 2016: Journal of Cardiothoracic and Vascular Anesthesia
https://www.readbyqxmd.com/read/28093494/exercise-dynamics-in-secondary-mitral-regurgitation-pathophysiology-and-therapeutic-implications
#6
Philippe B Bertrand, Ehud Schwammenthal, Robert A Levine, Pieter M Vandervoort
Secondary mitral valve regurgitation (MR) remains a challenging problem in the diagnostic workup and treatment of patients with heart failure. Although secondary MR is characteristically dynamic in nature and sensitive to changes in ventricular geometry and loading, current therapy is mainly focused on resting conditions. An exercise-induced increase in secondary MR, however, is associated with impaired exercise capacity and increased mortality. In an era where a multitude of percutaneous solutions are emerging for the treatment of patients with heart failure, it becomes important to address the dynamic component of secondary MR during exercise as well...
January 17, 2017: Circulation
https://www.readbyqxmd.com/read/28092726/pathophysiology-incidence-and-predictors-of-conduction-disturbances-during-transcatheter-aortic-valve-implantation
#7
Marco Barbanti, Simona Gulino, Giuliano Costa, Corrado Tamburino
Over the past decade, transcatheter aortic valve implantation (TAVI) has evolved rapidly toward an extremely reproducible, safe and effective procedure, with a marked reduction of its related complications. However, the occurrence of conduction disturbances and the need for permanent pacemaker implantation (PPI) after TAVI remains a concern. Areas covered: In this article review, we will go through the mechanisms involved in conduction disturbances after TAVI, and we will discuss the key aspects of pathophysiology, incidence and predictors of conduction disturbances following Transcatheter Aortic Valve Implantation...
January 16, 2017: Expert Review of Medical Devices
https://www.readbyqxmd.com/read/28090301/pulmonary-pulse-wave-transit-time-is-associated-with-right-ventricular-pulmonary-artery-coupling-in-pulmonary-arterial-hypertension
#8
Kurt W Prins, E Kenneth Weir, Stephen L Archer, Jeremy Markowitz, Lauren Rose, Marc Pritzker, Richard Madlon-Kay, Thenappan Thenappan
Pulmonary pulse wave transit time (pPTT), defined as the time for the systolic pressure pulse wave to travel from the pulmonary valve to the pulmonary veins, has been reported to be reduced in pulmonary arterial hypertension (PAH); however, the underlying mechanism of reduced pPTT is unknown. Here, we investigate the hypothesis that abbreviated pPTT in PAH results from impaired right ventricular-pulmonary artery (RV-PA) coupling. We quantified pPTT using pulsed-wave Doppler ultrasound from 10 healthy age- and sex-matched controls and 36 patients with PAH...
December 2016: Pulmonary Circulation
https://www.readbyqxmd.com/read/28089150/anticoagulant-bridging-in-left-sided-mechanical-heart-valve-patients
#9
E A Hart, R Jansen, T A Meijs, B J Bouma, R K Riezebos, W Tanis, W J P van Boven, V Hindori, N Wiersma, T Dessing, J Westerink, S A J Chamuleau
BACKGROUND: In preparation for an invasive procedure with a high bleeding risk, patients with a mechanical heart valve temporarily have to discontinue their anticoagulant therapy and are usually bridged with either intravenous unfractionated heparin (UFH) or subcutaneous low-molecular-weight heparin (LMWH). In this study we retrospectively analyzed the safety of UFH versus LMWH as bridging strategy in left-sided mechanical heart valve patients. METHODS: We performed a retrospective multicenter study in four surgical centers in The Netherlands...
January 6, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/28088917/effects-of-heart-valve-prostheses-on-phase-contrast-flow-measurements-in-cardiovascular-magnetic-resonance-a-phantom-study
#10
Johanna Richau, Matthias A Dieringer, Julius Traber, Florian von Knobelsdorff-Brenkenhoff, Andreas Greiser, Carsten Schwenke, Jeanette Schulz-Menger
BACKGROUND: Cardiovascular Magnetic Resonance is often used to evaluate patients after heart valve replacement. This study systematically analyses the influence of heart valve prostheses on phase contrast measurements in a phantom trial. METHODS: Two biological and one mechanical aortic valve prostheses were integrated in a flow phantom. B0 maps and phase contrast measurements were acquired at a 1.5 T MR scanner using conventional gradient-echo sequences in predefined distances to the prostheses...
January 16, 2017: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/28087742/heartbeat-warfarin-therapy-for-mechanical-heart-valves
#11
EDITORIAL
Catherine M Otto
No abstract text is available yet for this article.
February 2017: Heart: Official Journal of the British Cardiac Society
https://www.readbyqxmd.com/read/28087627/inhibition-of-cell-polarity-establishment-in-stomatal-asymmetric-cell-division-using-the-chemical-compound-bubblin
#12
Yumiko Sakai, Shigeo S Sugano, Takashi Kawase, Makoto Shirakawa, Yu Imai, Yusuke Kawamoto, Hiroshi Sugiyama, Tsuyoshi Nakagawa, Ikuko Hara-Nishimura, Tomoo Shimada
Stem-cell polarization is a crucial step in asymmetric cell division, which is a universal system for generating cellular diversity in multicellular organisms. Several conventional genetics studies have attempted to elucidate the mechanisms underlying cell polarization in plants, but it remains largely unknown. In plants, stomata, which are valves for gas exchange, are generated through several rounds of asymmetric divisions. In this study, we identified and characterized a chemical compound that affects stomatal stem-cell polarity...
January 13, 2017: Development
https://www.readbyqxmd.com/read/28081513/thrombosis-of-a-mechanical-prosthetic-aortic-valve-in-early-pregnancy-histopathological-findings
#13
Roman Scheidmann, Rudi Foth, Matthias Sigler
We present results of the histopathological workup of a prosthetic aortic valve which was explanted from a 31-year-old woman due to valve thrombosis during early pregnancy. Our images demonstrate nicely thrombotic material directly adherent to the pyrolytic carbon surface in a human specimen.
January 2, 2017: Cardiovascular Pathology: the Official Journal of the Society for Cardiovascular Pathology
https://www.readbyqxmd.com/read/28081130/comparative-ability-of-oropsylla-montana-and-xenopsylla-cheopis-fleas-to-transmit-yersinia-pestis-by-two-different-mechanisms
#14
B Joseph Hinnebusch, David M Bland, Christopher F Bosio, Clayton O Jarrett
BACKGROUND: Transmission of Yersinia pestis by flea bite can occur by two mechanisms. After taking a blood meal from a bacteremic mammal, fleas have the potential to transmit the very next time they feed. This early-phase transmission resembles mechanical transmission in some respects, but the mechanism is unknown. Thereafter, transmission occurs after Yersinia pestis forms a biofilm in the proventricular valve in the flea foregut. The biofilm can impede and sometimes completely block the ingestion of blood, resulting in regurgitative transmission of bacteria into the bite site...
January 2017: PLoS Neglected Tropical Diseases
https://www.readbyqxmd.com/read/28079798/clinical-and-genetic-factors-associated-with-warfarin-maintenance-dose-in-northern-chinese-patients-with-mechanical-heart-valve-replacement
#15
Rui Liu, Jian Cao, Qian Zhang, Xin-Miao Shi, Xiao-Dong Pan, Ran Dong
The effects of genetic variants on warfarin dosing vary among different ethnic groups, especially in the Chinese population. The objective of this study was to recruit patients through a rigorous experimental design and to perform a comprehensive screen to identify gene polymorphisms that may influence warfarin dosing in northern Han Chinese patients with mechanical heart valve replacement. Consenting patients (n = 183) with a stable warfarin dose were included in this study. Ninety-six single nucleotide polymorphisms (SNPs) in 30 genes involved in warfarin pharmacological pathways were genotyped using the Illumina SNP GoldenGate Assay, and their associations with warfarin dosing were assessed using univariate regression analysis with post hoc comparison using least significant difference analysis...
January 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28078820/improvement-of-the-in-vivo-cellular-repopulation-of-decellularized-cardiovascular-tissues-by-a-detergent-free-non-proteolytic-actin-disassembling-regimen
#16
Alexander Assmann, Marc Struß, Franziska Schiffer, Friederike Heidelberg, Hiroshi Munakata, Elena V Timchenko, Pavel E Timchenko, Tim Kaufmann, Khon Huynh, Yukiharu Sugimura, Quentin Leidl, Antonio Pinto, Volker R Stoldt, Artur Lichtenberg, Payam Akhyari
Low immunogenicity and high repopulation capacity are crucial determinants for the functional and structural performance of acellular cardiovascular implants. The present study evaluates a detergent-free, non-proteolytic, actin-disassembling regimen (BIO) for decellularization of heart valve and vessel grafts, particularly focusing on their bio-functionality. Rat aortic conduits (rAoC; n = 89) and porcine aortic valve samples (n = 106) are decellularized using detergents (group DET) or the BIO regimen...
January 11, 2017: Journal of Tissue Engineering and Regenerative Medicine
https://www.readbyqxmd.com/read/28077818/enlargement-of-the-excluded-left-atrial-appendage-with-thrombus
#17
Shigeaki Aoyagi, Satoru Tobinaga, Hiroyuki Saisho
We report progressive enlargement of the excluded left atrial appendage (LAA) with a thrombus in a patient who had undergone valve surgery and endocardial suture closure of the LAA previously. Echocardiography and CT detected no communication between the LAA and the left atrium. Magnetic resonance imaging showed the LAA was filled with fresh and old thrombi. Coronary arteriography demonstrated small left coronary artery-LAA fistulae. At surgery, successful exclusion of the LAA was confirmed after removal of the thrombi...
January 11, 2017: International Heart Journal
https://www.readbyqxmd.com/read/28076618/aortic-valve-replacement-treatment-by-sternotomy-versus-minimally-invasive-approach
#18
Renata Tosoni Rodrigues Ferreira, Roberto Rocha E Silva, Evaldo Marchi
Objective: To compare the results of aortic valve replacement with access by sternotomy or minimally invasive approach. Methods: Retrospective analysis of medical records of 37 patients undergoing aortic valve replacement by sternotomy or minimally invasive approach, with emphasis on the comparison of time of cardiopulmonary bypass and aortic clamping, volume of surgical bleeding, time of mechanical ventilation, need for blood transfusion, incidence of atrial fibrillation, length of stay in intensive care unit, time of hospital discharge, short-term mortality and presence of surgical wound infection...
November 2016: Brazilian Journal of Cardiovascular Surgery
https://www.readbyqxmd.com/read/28073568/three-mechanisms-of-early-failure-of-transcatheter-aortic-valves-valve-thrombosis-cusp-rupture-and-accelerated-calcification
#19
Matthew R Summers, Paul C Cremer, Wael A Jaber
No abstract text is available yet for this article.
December 14, 2016: Journal of Thoracic and Cardiovascular Surgery
https://www.readbyqxmd.com/read/28072861/identification-of-the-molecular-clockwork-of-the-oyster-crassostrea-gigas
#20
Mickael Perrigault, Damien Tran
Molecular clock system constitutes the origin of biological rhythms that allow organisms to anticipate cyclic environmental changes and adapt their behavior and physiology. Components of the molecular clock are largely conserved across a broad range of species but appreciable diversity in clock structure and function is also present especially in invertebrates. The present work aimed at identify and characterize molecular clockwork components in relationship with the monitoring of valve activity behavior in the oyster Crassostrea gigas...
2017: PloS One
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