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Cardiac physiology

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https://www.readbyqxmd.com/read/28636647/hemodynamic-and-metabolic-characteristics-associated-with-development-of-a-right-ventricular-outflow-tract-pressure-gradient-during-upright-exercise
#1
Annelieke C M J van Riel, David M Systrom, Rudolf K F Oliveira, Michael J Landzberg, Barbara J M Mulder, Berto J Bouma, Bradley A Maron, Amil M Shah, Aaron B Waxman, Alexander R Opotowsky
BACKGROUND: We recently reported a novel observation that many patients with equal resting supine right ventricular(RV) and pulmonary artery(PA) systolic pressures develop an RV outflow tract(RVOT) pressure gradient during upright exercise. The current work details the characteristics of patients who develop such an RVOT gradient. METHODS: We studied 294 patients (59.7±15.5 years-old, 49% male) referred for clinical invasive cardiopulmonary exercise testing, who did not have a resting RVOT pressure gradient defined by the simultaneously measured peak-to-peak difference between RV and PA systolic pressures...
2017: PloS One
https://www.readbyqxmd.com/read/28634611/micro-and-nano-patterned-conductive-graphene-peg-hybrid-scaffolds-for-cardiac-tissue-engineering
#2
Alec S T Smith, Hyok Yoo, Hyunjung Yi, Eun Hyun Ahn, Justin H Lee, Guozheng Shao, Ekaterina Nagornyak, Michael A Laflamme, Charles E Murry, Deok-Ho Kim
A lack of electrical conductivity and structural organization in currently available biomaterial scaffolds limits their utility for generating physiologically representative models of functional cardiac tissue. Here we report on the development of scalable, graphene-functionalized topographies with anisotropic electrical conductivity for engineering the structural and functional phenotypes of macroscopic cardiac tissue constructs. Guided by anisotropic electroconductive and topographic cues, the tissue constructs displayed structural property enhancement in myofibrils and sarcomeres, and exhibited significant increases in the expression of cell-cell coupling and calcium handling proteins, as well as in action potential duration and peak calcium release...
June 21, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28634555/a-rare-case-of-pneumopericardium-in-the-setting-of-tuberculous-constrictive-pericarditis
#3
Lauro L Abrahan Iv, Stephanie Martha O Obillos, Jaime Alfonso M Aherrera, Jose Donato A Magno, Celia Catherine C Uy-Agbayani, Ulysses King G Gopez, Jobelle Joyce Anne R Baldonado
A 28-year-old Filipino male was admitted due to high-grade fevers and dyspnea on a background of chronic cough and weight loss. Due to clinical and echocardiographic signs of cardiac tamponade, emergency pericardiocentesis was performed on his first hospital day. Five days after, chest radiographs showed new pockets of radiolucency within the cardiac shadow, indicative of pneumopericardium. On repeat echo, air microbubbles admixed with loculated effusion were visualized in the anterior pericardial space. Constrictive physiology was also supported by a thickened pericardium, septal bounce, exaggerated respiratory variation in AV valve inflow, and IVC plethora...
2017: Case Reports in Cardiology
https://www.readbyqxmd.com/read/28631764/-hemodynamic-effects-of-positive-end-expiratory-pressure
#4
Marco Marini, Giorgio Caretta, Fabio Vagnarelli, Fabiana Lucà, Emilia Biscottini, Alberto Lavorgna, Vincenza Procaccini, Letizia Riva, Gabriele Vianello, Nadia Aspromonte, Andrea Mortara, Renata De Maria, Piera Capasso, Serafina Valente, Michele Massimo Gulizia
The application of a positive end-expiratory pressure (PEEP), the cornerstone of noninvasive ventilation (NIV), causes hemodynamic changes in the cardiovascular system. To understand the benefits of NIV it is necessary to resume concepts of cardiovascular physiology and pathophysiology about cardiac function determinants, venous return, ventricular interdependence and heart-lung interaction, and to understand how PEEP interacts with them. The hemodynamic effects of PEEP are mediated by the increase in transpulmonary pressure, which results in increased pulmonary vascular resistance and in an attending small reduction of venous return in conditions of euvolemia, in a substantial reduction of left ventricular afterload and a potential positive effect on left ventricular stroke volume...
June 2017: Giornale Italiano di Cardiologia
https://www.readbyqxmd.com/read/28630575/acute-and-post-exercise-physiological-responses-to-high-intensity-interval-training-in-endurance-and-sprint-athletes
#5
Lukas Cipryan, Gerhard Tschakert, Peter Hofmann
The purpose of the presented study was to compare acute and post-exercise differences in cardiorespiratory, metabolic, cardiac autonomic, inflammatory and muscle damage responses to high-intensity interval exercise (HIIT) between endurance and sprint athletes. The study group consisted of sixteen highly-trained males (age 22.1 ± 2.5 years) participating in endurance (n = 8) or sprint (n = 8) sporting events. All the participants underwent three exercise sessions: short HIIT (work interval duration 30s), long HIIT (3min) and constant load exercise (CE)...
June 2017: Journal of Sports Science & Medicine
https://www.readbyqxmd.com/read/28630000/betaine-aldehyde-dehydrogenase-expression-during-physiological-cardiac-hypertrophy-induced-by-pregnancy
#6
Jesús Alfredo Rosas-Rodríguez, José Guadalupe Soñanez-Organis, José Arquimides Godoy-Lugo, Juan Alberto Espinoza-Salazar, Cesar Jeravy López-Jacobo, Norma Aurora Stephens-Camacho, Guadalupe González-Ochoa
Betaine Aldehyde Dehydrogenase (betaine aldehyde: NAD(P)(+) oxidoreductase, (E.C. 1.2.1.8; BADH) catalyze the irreversible oxidation of betaine aldehyde (BA) to glycine betaine (GB) and is essential for polyamine catabolism, γ-aminobutyric acid synthesis, and carnitine biosynthesis. GB is an important osmolyte that regulates the homocysteine levels, contributing to a vascular risk factor reduction. In this sense, distinct investigations describe the physiological roles of GB, but there is a lack of information about the GB novo synthesis process and regulation during cardiac hypertrophy induced by pregnancy...
June 16, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28629808/physiological-and-pathophysiological-role-of-transient-receptor-potential-canonical-channels-in-cardiac-myocytes
#7
REVIEW
Azmi A Ahmad, Molly Streiff, Chris Hunter, Qinghua Hu, Frank B Sachse
Transient receptor potential canonical (TRPC) channels constitute a family of seven Ca(2+) permeable ion channels, named TRPC1 to 7. These channels are abundantly expressed in the mammalian heart, yet mechanisms underlying activation of TRPC channels and their precise role in cardiac physiology remain poorly understood. In this review, we perused original literature regarding TRPC channels in cardiomyocytes. We first reviewed studies on TRPC channel assembly and sub-cellular localization across multiple species and cell types...
June 16, 2017: Progress in Biophysics and Molecular Biology
https://www.readbyqxmd.com/read/28627693/renal-denervation-attenuates-cardiac-hypertrophy-in-spontaneously-hypertensive-rats-via-regulation-of-autophagy
#8
Jionghua Huang, He Huang, Wei Pan, Dejin Ou, Wenjun Dai, Yuhui Lin, Jinlei Wu, Wenjie Xie, Ximing Chen
It has been suggested that renal denervation (RD) may attenuate left ventricular (LV) hypertrophy. However, the role that autophagy serves in this process is currently unclear. In the present study, utilizing a model of hypertension‑induced cardiac hypertrophy in spontaneous hypertensive rats, it was demonstrated that RD was significantly associated with a reduction in LV hypertrophy. Furthermore, a decrease in the myocardial mRNA of hypertrophy‑associated genes was demonstrated in RD rats compared with sham controls...
June 15, 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/28627028/common-findings-in-late-gestation-fetal-echocardiography
#9
Lauren Tague, Mary T Donofrio, Amanda Fulgium, Robert McCarter, Catherine Limperopoulos, David N Schidlow
OBJECTIVES: Fetal echocardiography provides detailed information about cardiac structure and function in utero. Limited information is available regarding normal findings late in pregnancy. We therefore sought to identify and describe common cardiac findings in late gestation. METHODS: Fetuses with structurally normal hearts were identified in mid gestation within a subset of pregnant women in a prospective study. The atrioventricular valves, right and left atria, aortic isthmus and ductus arteriosus dimensions and flow abnormalities, aneurysm of the septum primum, and presence and grade of tricuspid regurgitation were assessed throughout pregnancy...
June 19, 2017: Journal of Ultrasound in Medicine: Official Journal of the American Institute of Ultrasound in Medicine
https://www.readbyqxmd.com/read/28626082/significant-role-of-the-cardio-postural-interaction-in-blood-pressure-regulation-during-standing
#10
Da Xu, Ajay Verma, Amanmeet Garg, Michelle Bruner, Reza Fazel-Rezai, Andrew P Blaber, Kouhyar Tavakolian
Cardiovascular and postural control systems have been studied independently despite the increasing evidence showing the importance of cardio-postural interaction in blood pressure regulation. In this study, we aimed to assess the role of cardio-postural interaction in relation to cardiac baroreflex in blood pressure regulation under orthostatic stress before and after mild exercise. Physiological variables representing cardiovascular control (heart rate and systolic blood pressure), lower limb muscle activation (electromyography), and postural sway (center of pressure derived from force and moment data during sway) were measured from 17 healthy participants (25±2 years; 8 females) during a sit-to-stand test before and after sub-maximal exercise...
June 16, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28625234/-effect-of-global-end-diastolic-volume-index-guidance-fluid-resuscitation-in-elderly-patients-with-septic-shock
#11
Shuang Ma, Rumin Zhang, Shifu Wang, Meiling Zhao, Lei Wang, Yun Zhang
OBJECTIVE: To evaluate the effect of global end diastolic volume index (GEDVI) on fluid resuscitation in elderly patients with septic shock. METHODS: A prospective randomized controlled trial (RCT) was conducted. Septic shock patients over 65 years admitted to intensive care unit (ICU) of Shandong Province, Zibo Central Hospital from January 2013 to December 2015 were enrolled. The patients were randomly divided into control group and observation group, 20 cases in each group...
June 2017: Zhonghua Wei Zhong Bing Ji Jiu Yi Xue
https://www.readbyqxmd.com/read/28624396/hybrid-magnetic-resonance-imaging-and-positron-emission-tomography-with-fluorodeoxyglucose-to-diagnose-active-cardiac-sarcoidosis
#12
Marc R Dweck, Ronan Abgral, Maria Giovanna Trivieri, Philip M Robson, Nicolas Karakatsanis, Venkatesh Mani, Anna Palmisano, Marc A Miller, Anuradha Lala, Helena L Chang, Javier Sanz, Johanna Contreras, Jagat Narula, Valentin Fuster, Maria Padilla, Zahi A Fayad, Jason C Kovacic
OBJECTIVES: The purpose of this study was to explore the diagnostic usefulness of hybrid cardiac magnetic resonance (CMR) and positron emission tomography (PET) using 18F-fluorodeoxyglucose (FDG) for active cardiac sarcoidosis. BACKGROUND: Active cardiac sarcoidosis (aCS) is underdiagnosed and has a high mortality. METHODS: Patients with clinical suspicion of aCS underwent hybrid CMR/PET with late gadolinium enhancement (LGE) and FDG to assess the pattern of injury and disease activity, respectively...
June 9, 2017: JACC. Cardiovascular Imaging
https://www.readbyqxmd.com/read/28624121/leptin-like-immunoreactivity-in-the-central-nervous-system-digestive-organs-and-gonads-of-the-giant-freshwater-prawn-macrobrachium-rosenbergii
#13
Jaruwan Poljaroen, Yotsawan Tinikul, Ruchanok Tinikul, Panat Anurucpreeda, Prasert Sobhon
Leptin, a highly conserved adipocyte-derived hormone, plays important roles in a variety of physiological processes, including the control of fat storage and metabolic status which are linked to food intake, energy homeostasis, and reproduction in all vertebrates. In the present study, we hypothesize that leptin is also present in various organs of the fresh water prawns, Macrobrachium rosenbergii. The existence and distribution of a leptin-like peptide in prawn tissues were verified by using Western blotting (WB) and immunohistochemical detection (ID) using primary antibody against human leptin...
June 14, 2017: Acta Histochemica
https://www.readbyqxmd.com/read/28621257/oral-transmucosal-detomidine-gel-in-new-zealand-white-rabbits-oryctolagus-cuniculus
#14
Morika D Williams, C Tyler Long, Jessica R Durrant, Gabriel P McKeon, Heather R Shive, Emily H Griffith, Kristen M Messenger, Richard E Fish
Handling and restraining rabbits for routine procedures may be impossible without prior sedation, result in unnecessarystress or injury to the rabbit or handler, and increase experimental variability. Parenteral administration of sedatives can cause stress also, as well as localized pain and tissue damage, especially in fractious animals. Detomidine hydrochloride, an α2-adrenergic receptor agonist, is commercially available in an oral transmucosal (OTM) gel formulation that is FDA-approved for sedation and restraint in horses...
June 15, 2017: Journal of the American Association for Laboratory Animal Science: JAALAS
https://www.readbyqxmd.com/read/28615966/acute-physiological-and-electrical-accentuation-of-vagal-tone-has-no-effect-on-pain-or-gastrointestinal-motility-in-chronic-pancreatitis
#15
Jacob Juel, Christina Brock, Søren S Olesen, Adnan Madzak, Adam D Farmer, Qasim Aziz, Jens B Frøkjær, Asbjørn Mohr Drewes
BACKGROUND: The effective management of pain in chronic pancreatitis (CP) remains a therapeutic challenge. Analgesic drugs, such as opioids, and the underlying pathology can impair gut function. The autonomic nervous system influences hormone secretion and gut motility. In healthy volunteers, electrical (using noninvasive transcutaneous vagal nerve stimulation [t-VNS]) and physiological (using deep slow breathing [DSB]) modulation of parasympathetic tone results in pain attenuation and enhanced gut motility...
2017: Journal of Pain Research
https://www.readbyqxmd.com/read/28615705/a-long-term-and-slow-releasing-hydrogen-sulfide-donor-protects-against-myocardial-ischemia-reperfusion-injury
#16
Xiaotian Sun, Wenshuo Wang, Jing Dai, Sheng Jin, Jiechun Huang, Changfa Guo, Chunsheng Wang, Liewen Pang, Yiqing Wang
Hydrogen sulfide (H2S) has been recognized as an important gasotransmitter exerting various physiological effects, especially in the cardiovascular system. Herein we investigated the cardioprotective effects of a novel long-term and slow-releasing H2S donor, DATS-MSN, using in vivo myocardial ischemia/reperfusion (I/R) models and in vitro hypoxia/reoxygenation cardiomyocyte models. Unlike the instant-releasing pattern of sodium hydrosulphide (NaHS), the release of H2S from DATS-MSN was quite slow and continuous both in the cell culture medium and in rat plasma (elevated H2S concentrations during 24 h and 72 h reperfusion)...
June 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28615142/overexpression-of-kcnj2-in-induced-pluripotent-stem-cell-derived-cardiomyocytes-for-the-assessment-of-qt-prolonging-drugs
#17
Min Li, Yasunari Kanda, Takashi Ashihara, Tetsuo Sasano, Yuji Nakai, Masami Kodama, Erina Hayashi, Yuko Sekino, Tetsushi Furukawa, Junko Kurokawa
Human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes hold great potentials to predict pro-arrhythmic risks in preclinical cardiac safety screening, although the hiPSC cardiomyocytes exhibit rather immature functional and structural characteristics, including spontaneous activity. Our physiological characterization and mathematical simulation showed that low expression of the inward-rectifier potassium (IK1) channel is a determinant of spontaneous activity. To understand impact of the low IK1 expression on the pharmacological properties, we tested if transduction of hiPSC-derived cardiomyocytes with KCNJ2, which encodes the IK1 channel, alters pharmacological response to cardiac repolarization processes...
May 27, 2017: Journal of Pharmacological Sciences
https://www.readbyqxmd.com/read/28614863/-anesthetic-management-in-thoracic-trauma-patients
#18
Alf Kozian, Astrid Bergmann, Thomas Hachenberg, Thomas Schilling
In daily practice, management of patients with blunt thoracic trauma is challenging for the anesthetist. Injuries of airways, lungs, diaphragm, heart and large vessels are the main difficulties.Respiratory and circulatory physiology in general is affected by general anesthesia, which may result in an increased number of perioperative complications. Therefore, anesthetic management of patients with thoracic trauma needs to address different clinical topics: management of difficult airways, intrinsic effects of anesthetics and mechanical ventilation on respiratory and cardiac function, the adequate replacement of blood loss as well as type and extent of the surgical intervention...
June 2017: Anästhesiologie, Intensivmedizin, Notfallmedizin, Schmerztherapie: AINS
https://www.readbyqxmd.com/read/28614095/the-value-of-dynamic-preload-variables-during-spontaneous-ventilation
#19
Azriel Perel
PURPOSE OF REVIEW: To discuss the physiological significance and clinical value of dynamic preload variables in spontaneously breathing patients. RECENT FINDINGS: Dynamic preload variables reflect the response of the cardiac output to a modification of preload and can therefore be used to assess fluid responsiveness. Continuous dynamic parameters that are calculated from the variations in the arterial and plethysmographic waveforms following a mechanical breath have been shown to predict fluid responsiveness much better than static preload parameters...
June 12, 2017: Current Opinion in Critical Care
https://www.readbyqxmd.com/read/28614072/controversies-in-cardiopulmonary-death
#20
Michael G Fara, Breehan Chancellor, Aaron S Lord, Ariane Lewis
We describe two unusual cases of cardiopulmonary death in mechanically ventilated patients in the neurological intensive care unit. After cardiac arrest, both patients were pulseless for a protracted period. Upon extubation, both developed agonal movements (gasping respiration) resembling life. We discuss these cases and the literature on the ethical and medical controversies associated with determining time of cardiopulmonary death. We conclude that there is rarely a single moment when all of a patient's physiological functions stop working at once...
2017: Journal of Clinical Ethics
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