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https://www.readbyqxmd.com/read/28202552/airway-dynamics-in-copd-patients-by-within-breath-impedance-tracking-effects-of-continuous-positive-airway-pressure
#1
András Lorx, Dorottya Czövek, Zoltán Gingl, Gergely Makan, Bence Radics, Dóra Bartusek, Szabolcs Szigeti, János Gál, György Losonczy, Peter D Sly, Zoltán Hantos
Tracking of the within-breath changes of respiratory mechanics using the forced oscillation technique may provide outcomes that characterise the dynamic behaviour of the airways during normal breathing.We measured respiratory resistance (Rrs) and reactance (Xrs) at 8 Hz in 55 chronic obstructive pulmonary disease (COPD) patients and 20 healthy controls, and evaluated Rrs and Xrs as functions of gas flow (V') and volume (V) during normal breathing cycles. In 12 COPD patients, additional measurements were made at continuous positive airway pressure (CPAP) levels of 4, 8, 14 and 20 hPa...
February 2017: European Respiratory Journal: Official Journal of the European Society for Clinical Respiratory Physiology
https://www.readbyqxmd.com/read/28188007/volumetric-contributions-of-loop-regions-of-g-quadruplex-dna-to-the-formation-of-the-tertiary-structure
#2
Shuntaro Takahashi, Naoki Sugimoto
DNA guanine-quadruplexes (G-quadruplexes) are unique DNA structures formed by guanine-rich sequences. The loop regions of G-quadruplexes play key roles in stability and topology of G-quadruplexes. Here, we investigated volumetric changes induced by pressure in the folding of the G-quadruplex formed by the thrombin binding aptamer (TBA) with mutations within the loop regions. The change of partial molar volume in the transition from coil to G-quadruplex, ∆Vtr, of TBA with a mutation from T to A in the 5' most loop (TBA T3A) was 75...
February 6, 2017: Biophysical Chemistry
https://www.readbyqxmd.com/read/28162829/the-role-of-loops-and-cation-on-the-volume-of-unfolding-of-g-quadruplexes-related-to-htel
#3
Yang Yun Li, David N Dubins, Dianna My Nhi Thi Le, Karen Leung, Robert B Macgregor
In aqueous solutions containing sodium or potassium cations, oligodeoxyribonucleotides (ODNs) rich in guanine form four-stranded DNA structures called G-quadruplexes (G4s). These structures are destabilized by elevated hydrostatic pressure. Here, we use pressure to investigate the volumetric changes arising from the formation of G4 structures. G4s display a great deal of structural heterogeneity that depends on the stabilizing cation as well as the oligonucleotide sequence. Using UV thermal unfolding at different pressures, we have investigated the volume change of the helix-coil equilibrium of a series of ODNs whose sequences are related to the G-rich ODN HTel (d[A(GGGTTA)3GGG]), which contains four repeats of the human telomeric sequence...
January 6, 2017: Biophysical Chemistry
https://www.readbyqxmd.com/read/28134561/long-term-low-dose-dietary-resveratrol-supplement-reduces-cardiovascular-structural-and-functional-deterioration-in-chronic-heart-failure-in-rats
#4
Ismayil Ahmet, Hyun-Jin Tae, Edward G Lakatta, Mark Talan
A short-term exposure to resveratrol at high dosages exerts a remarkable cardioprotective effect. Whether a long-term exposure to resveratrol at low dosages that can be obtained through consumption of a resveratrol-rich diet is beneficial to heart diseases is unknown. We tested the effects of a resveratrol-enriched diet on cardiovascular remodeling of chronic heart failure (CHF) in rats resulting from permanent ligation of left coronary artery. Two weeks after surgery, rats were started on either a resveratrol-enriched (R; 5 mg/kg per day; n = 23) or normal (Control; n = 23) diet for next 10 months...
December 17, 2016: Canadian Journal of Physiology and Pharmacology
https://www.readbyqxmd.com/read/28116751/cardiac-sympathetic-afferent-reflex-control-of-cardiac-function-in-normal-and-chronic-heart-failure-states
#5
Han-Jun Wang, George J Rozanski, Irving H Zucker
The enhanced "cardiac sympathetic afferent reflex" (CSAR) critically contributes to the exaggerated global sympathetic tone in chronic heart failure (CHF). However, a potential contribution of the cardio-cardiac reflex control of cardiac function in both normal and CHF states remains unknown. In this study, we evaluated the effects of direct activation or inhibition of the CSAR on cardiac function by pressure-volume (P-V) loop analysis in ∼12-week sham-operated and myocardial infarcted (MI) rats. In sham rats, acute CSAR activation by epicardial application of bradykinin (BK) increased heart rate (HR), left ventricular systolic pressure (LVSP), dp/dtmax , and the slope of the end-systolic P-V relationship (ESPVR), suggesting that acute CSAR activation in the normal state enhances myocardial contractility...
January 24, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28105847/compact-ultrahigh-pressure-nanoflow-capillary-liquid-chromatograph
#6
Xiaofeng Zhao, Xiaofeng Xie, Sonika Sharma, Luke T Tolley, Alex Plistil, Hal E Barnett, Martin P Brisbin, Adam C Swensen, John C Price, Paul B Farnsworth, H Dennis Tolley, Stanley D Stearns, Milton L Lee
A compact ultrahigh-pressure nanoflow liquid chromatograph (LC) was developed with the purpose in mind of creating a portable system that could be easily moved to various testing locations or placed in close proximity to other instruments for optimal coupling, such as with mass spectrometry (MS). The system utilized innovative nanoflow pumps integrated with a very low volume stop-flow injector and mixing tee. The system weighed only 5.9 kg (13 lbs) or 4.5 kg (10 lbs) without a controller and could hold up to 1100 bar (16000 psi) of pressure...
January 3, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28096417/phosphorylation-by-pkc-and-pka-regulate-the-kinase-activity-and-downstream-signaling-of-wnk4
#7
Maria Castañeda-Bueno, Juan Pablo Arroyo, Junhui Zhang, Jeremy Puthumana, Orlando Yarborough, Shigeru Shibata, Lorena Rojas-Vega, Gerardo Gamba, Jesse Rinehart, Richard P Lifton
With-no-lysine kinase 4 (WNK4) regulates electrolyte homeostasis and blood pressure. WNK4 phosphorylates the kinases SPAK (Ste20-related proline alanine-rich kinase) and OSR1 (oxidative stress responsive kinase), which then phosphorylate and activate the renal Na-Cl cotransporter (NCC). WNK4 levels are regulated by binding to Kelch-like 3, targeting WNK4 for ubiquitylation and degradation. Phosphorylation of Kelch-like 3 by PKC or PKA downstream of AngII or vasopressin signaling, respectively, abrogates binding...
January 31, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28043677/pressure-volume-loop-derived-cardiac-indices-during-dobutamine-stress-a-step-towards-understanding-limitations-in-cardiac-output-in-children-with-hypoplastic-left-heart-syndrome
#8
James Wong, Kuberan Pushparajah, Adelaide de Vecchi, Bram Ruijsink, Gerald F Greil, Tarique Hussain, Reza Razavi
BACKGROUND: Children with a single systemic right ventricle, such as in hypoplastic left heart syndrome (HLHS), frequently experience reduced exercise capacity. Elucidating the causes could help with optimising treatment strategies. METHODS: Prospective data from 10 consecutive symptomatic patients with HLHS undergoing clinical cardiac magnetic resonance with catheterisation (XMR) were analysed. Mean age 8.6years (range 3.5-11.6years), mean time since Fontan completion 5...
March 1, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/28029367/on-the-feasibility-to-conduct-gradient-liquid-chromatography-separations-in-narrow-bore-columns-at-pressures-up-to-2000bar
#9
Ruben De Pauw, Tim Swier, Bart Degreef, Gert Desmet, Ken Broeckhoven
The limits in operating pressures are extended for narrow-bore columns in gradient elution up to 2000bar. As the required pumps for these pressures are incompatible with common chromatographic solvents and are not suitable to apply a mobile phase composition gradient, a mobile phase delivery and injection system is described and experimentally validated which allows to use any possible chromatographic solvent in isocratic and gradient elution. The mobile phase delivery and injection system also allows to perform multiple separations without the need to depressurize the column...
October 6, 2016: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28026740/comparative-hemodynamic-effects-of-contemporary-percutaneous-mechanical-circulatory-support-devices-in-a-porcine-model-of-acute-myocardial-infarction
#10
Brian R Weil, Filip Konecny, Gen Suzuki, Vijay Iyer, John M Canty
OBJECTIVES: The aim of this study was to directly compare the hemodynamic effects of 2 contemporary percutaneous mechanical circulatory support devices in a porcine model of acute myocardial infarction. BACKGROUND: Percutaneous support devices offer the ability to unload the ischemic left ventricle, but the comparative hemodynamic effects of contemporary platforms are unclear. METHODS: Yorkshire swine (mean weight 76 ± 2 kg; n = 7) were instrumented with a left ventricular (LV) pressure-volume (PV) catheter and subjected to a 2-h coronary occlusion...
November 28, 2016: JACC. Cardiovascular Interventions
https://www.readbyqxmd.com/read/28008296/point-of-care-ultraportable-echocardiography-predicts-diuretic-response-in-patients-admitted-with-acute-decompensated-heart-failure
#11
Dena K Krishnan, Barbara Pawlaczyk, Peter A McCullough, Susan Enright, Arvind Kunadi, Thomas E Vanhecke
BACKGROUND: Routine management of patients with acute decompensated heart failure (ADHF) requires careful attentiveness to fluid status and diuretic treatment efficacy. New advances in ultrasound have made ultraportable echocardiography (UE) available to physicians for point-of-care use. The purpose of this study is to explore physiologic measures of intravascular fluid volume derived from UE and explore predictors of diuretic response in ADHF. METHODS: Various echocardiography imaging measurements, particularly diameter and collapse of inferior vena cava (IVC), were collected from 77 patients admitted with a primary diagnosis of ADHF...
2016: Clinical Medicine Insights. Cardiology
https://www.readbyqxmd.com/read/28003648/cardiac-structural-remodeling-in-hypertensive-cardiomyopathy
#12
Si-Jia Sun, Jia-Lu Yao, Lang-Biao Xu, Qing Rui, Nan-Nan Zhang, Min Chen, Yu-Feng Jiang, Hua-Jia Yang, Ya-Feng Zhou
Heart failure with preserved ejection fraction (HFpEF), which is a primary driver of morbidity and mortality, accounts for approximately half of all heart failure cases. Therefore, it is essential to develop preclinical animal models for HFpEF pharmacological treatment strategies. We created a porcine model of severe hypertension and hyperlipidemia by using a combination of deoxycorticosterone acetate (DOCA, 100 mg kg(-1)), Western diet (WD) and angiotensin II infusion. Systolic blood pressure, echocardiography and invasive pressure-volume loop were assessed at baseline, 12 weeks and 18 weeks...
December 22, 2016: Hypertension Research: Official Journal of the Japanese Society of Hypertension
https://www.readbyqxmd.com/read/28000751/suppression-of-nlrp3-inflammasome-activation-ameliorates-chronic-kidney-disease-induced-cardiac-fibrosis-and-diastolic-dysfunction
#13
Antoinette Bugyei-Twum, Armin Abadeh, Kerri Thai, Yanling Zhang, Melissa Mitchell, Golam Kabir, Kim A Connelly
Cardiac fibrosis is a common finding in patients with chronic kidney disease. Here, we investigate the cardio-renal effects of theracurmin, a novel formulation of the polyphenolic compound curcumin, in a rat model of chronic kidney disease. Briefly, Sprague-Dawley rats were randomized to undergo sham or subtotal nephrectomy (SNx) surgery. At 3 weeks post surgery, SNx animals were further randomized to received theracurmin via once daily oral gavage or vehicle for 5 consecutive weeks. At 8 weeks post surgery, cardiac function was assessed via echocardiography and pressure volume loop analysis, followed by LV and renal tissue collection for analysis...
December 21, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27987598/role-of-vessel-to-prosthesis-size-mismatch-in-venous-valve-performance
#14
Wei-Hsin Tien, Xuefeng Zhao, Henry Y Chen, Zachary C Berwick, Joshua F Krieger, Sean Chambers, Dana Dabiri, Ghassan S Kassab
BACKGROUND: Efforts to treat chronic venous insufficiency have focused on the development of prosthetic venous valves. The role of prosthetic valve-to-vessel size matching has not been determined. The purpose of this investigation was to assess the effect of size mismatching on venous valve function and to establish a mismatch limit that affects valve hemodynamic performance and venous wall stress to improve future valve designs and implants. METHODS: Flow dynamics of prosthetic venous valves were studied in vitro using a pulse duplicator flow loop...
January 2017: Journal of Vascular Surgery. Venous and Lymphatic Disorders
https://www.readbyqxmd.com/read/27987352/design-of-a-right-ventricular-mock-circulation-loop-as-a-test-bench-for-right-ventricular-assist-devices
#15
Indra Mueller, So-Hyun Jansen-Park, Michael Neidlin, Ulrich Steinseifer, Dirk Abel, Rüdiger Autschbach, Rolf Rossaint, Thomas Schmitz-Rode, Simon Johannes Sonntag
Right heart failure (RHF), e.g. due to pulmonary hypertension (PH), is a serious health issue with growing occurrence and high mortality rate. Limited efficacy of medication in advanced stages of the disease constitutes the need for mechanical circulatory support of the right ventricle (RV). An essential contribution to the process of developing right ventricular assist devices (RVADs) is the in vitro test bench, which simulates the hemodynamic behavior of the native circulatory system. To model healthy and diseased arterial-pulmonary hemodynamics in adults (mild and severe PH and RHF), a right heart mock circulation loop (MCL) was developed...
December 17, 2016: Biomedizinische Technik. Biomedical Engineering
https://www.readbyqxmd.com/read/27979981/effects-of-different-stresses-on-cardiac-autonomic-control-and-cardiovascular-coupling
#16
Lin Xie, Binbin Liu, Xiaoni Wang, Mengqi Mei, Mengjun Li, Xiaolin Yu, Jianbao Zhang
The objective of this study was to investigate the impacts of different stresses on time varying autonomic reactivity and cardiovascular coupling. In total, 25 male subjects were recruited. RR intervals (RRI), systolic and diastolic blood pressure (SBP, DBP), stroke volume (SV), cardiac output (CO) and systemic vascular resistance (SVR) values were collected during rest, mental arithmetic task (MAT) and cold pressor test (CPT). Baroreflex sensitivity (BRS) was derived using the transfer function method. Continuous wavelet transform of RRI was used to describe the time variant patterns of autonomic neural activities...
December 15, 2016: Journal of Applied Physiology
https://www.readbyqxmd.com/read/27978950/gene-therapy-with-angiotensin-1-9-preserves-left-ventricular-systolic-function-after-myocardial-infarction
#17
Caroline Fattah, Katrin Nather, Charlotte S McCarroll, Maria P Hortigon-Vinagre, Victor Zamora, Monica Flores-Munoz, Lisa McArthur, Lorena Zentilin, Mauro Giacca, Rhian M Touyz, Godfrey L Smith, Christopher M Loughrey, Stuart A Nicklin
BACKGROUND: Angiotensin-(1-9) [Ang-(1-9)] is a novel peptide of the counter-regulatory axis of the renin-angiotensin-aldosterone system previously demonstrated to have therapeutic potential in hypertensive cardiomyopathy when administered via osmotic mini-pump. Here, we investigate whether gene transfer of Ang-(1-9) is cardioprotective in a murine model of myocardial infarction (MI). OBJECTIVES: The authors evaluated effects of Ang-(1-9) gene therapy on myocardial structural and functional remodeling post-infarction...
December 20, 2016: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/27916176/functional-assessment-and-transplantation-of-the-donor-heart-after-circulatory-death
#18
Simon J Messer, Richard G Axell, Simon Colah, Paul A White, Marian Ryan, Aravinda A Page, Barbora Parizkova, Kamen Valchanov, Christopher W White, Darren H Freed, Euan Ashley, John Dunning, Martin Goddard, Jayan Parameshwar, Christopher J Watson, Thomas Krieg, Ayyaz Ali, Steven Tsui, Stephen R Large
BACKGROUND: After a severe shortage of brain-dead donors, the demand for heart transplantation has never been greater. In an attempt to increase organ supply, abdominal and lung transplant programs have turned to the donation after circulatory-determined death (DCD) donor. However, because heart function cannot be assessed after circulatory death, DCD heart transplantation was deemed high risk and never adopted routinely. We report a novel method of functional assessment of the DCD heart resulting in a successful clinical program...
December 2016: Journal of Heart and Lung Transplantation
https://www.readbyqxmd.com/read/27913141/acute-lung-injury-and-persistent-small-airway-disease-in-a-rabbit-model-of-chlorine-inhalation
#19
Sadiatu Musah, Connie F Schlueter, David M Humphrey, Karen S Powell, Andrew M Roberts, Gary W Hoyle
Chlorine is a pulmonary toxicant to which humans can be exposed through accidents or intentional releases. Acute effects of chlorine inhalation in humans and animal models have been well characterized, but less is known about persistent effects of acute, high-level chlorine exposures. In particular, animal models that reproduce the long-term effects suggested to occur in humans are lacking. Here, we report the development of a rabbit model in which both acute and persistent effects of chlorine inhalation can be assessed...
January 15, 2017: Toxicology and Applied Pharmacology
https://www.readbyqxmd.com/read/27908351/pim1-kinase-overexpression-enhances-ckit-cardiac-stem-cell-cardiac-repair-following-myocardial-infarction-in-swine
#20
Shathiyah Kulandavelu, Vasileios Karantalis, Julia Fritsch, Konstantinos E Hatzistergos, Viky Y Loescher, Frederic McCall, Bo Wang, Luiza Bagno, Samuel Golpanian, Ariel Wolf, Justin Grenet, Adam Williams, Aaron Kupin, Aaron Rosenfeld, Sadia Mohsin, Mark A Sussman, Azorides Morales, Wayne Balkan, Joshua M Hare
BACKGROUND: Pim1 kinase plays an important role in cell division, survival, and commitment of precursor cells towards a myocardial lineage, and overexpression of Pim1 in ckit(+) cardiac stem cells (CSCs) enhances their cardioreparative properties. OBJECTIVES: The authors sought to validate the effect of Pim1-modified CSCs in a translationally relevant large animal preclinical model of myocardial infarction (MI). METHODS: Human cardiac stem cells (hCSCs, n = 10), hckit(+) CSCs overexpressing Pim1 (Pim1(+); n = 9), or placebo (n = 10) were delivered by intramyocardial injection to immunosuppressed Yorkshire swine (n = 29) 2 weeks after MI...
December 6, 2016: Journal of the American College of Cardiology
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