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Heart physiology

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https://www.readbyqxmd.com/read/28820653/fibrous-skeleton-of-the-heart-anatomic-overview-and-evaluation-of-pathologic-conditions-with-ct-and-mr-imaging
#1
Farhood Saremi, Damián Sánchez-Quintana, Shumpei Mori, Horia Muresian, Diane E Spicer, Cameron Hassani, Robert H Anderson
The fibrous skeleton is concentrated at the base of the ventricular mass. It provides electrical insulation at the atrioventricular level and fibrous continuity for the leaflets of the mitral, aortic, and tricuspid valves. Its components include the fibrous trigones, the fibrous area of aortic-mitral continuity, the subvalvar collar of the mitral valve, the membranous septum, the interleaflet triangles, the tendon of Todaro, and likely the conus ligament. The majority of the mitral annulus is fibrous, but the only true fibrous part of the tricuspid annulus is where the valvar leaflets are attached to the central fibrous body...
August 18, 2017: Radiographics: a Review Publication of the Radiological Society of North America, Inc
https://www.readbyqxmd.com/read/28820609/cardio-pulmonary-interactions-physiologic-basis-and-clinical-applications
#2
Michael R Pinsky
The hemodynamic effects of ventilation can be grouped into three concepts: 1) spontaneous ventilation is exercise; 2) changes in lung volume alter autonomic tone, pulmonary vascular resistance, and can compress the heart in the cardiac fossa; 3) spontaneous inspiratory efforts decrease intrathoracic pressure (ITP) increasing venous return and impeding left ventricular (LV) ejection; whereas positive pressure ventilation decreases venous return and unloads LV ejection. Spontaneous inspiratory efforts may induce acute LV failure and cardiogenic pulmonary edema...
August 18, 2017: Annals of the American Thoracic Society
https://www.readbyqxmd.com/read/28820467/aquaporin-4-functionality-and-virchow-robin-space-water-dynamics-physiological-model-for-neurovascular-coupling-and-glymphatic-flow
#3
REVIEW
Tsutomu Nakada, Ingrid L Kwee, Hironaka Igarashi, Yuji Suzuki
The unique properties of brain capillary endothelium, critical in maintaining the blood-brain barrier (BBB) and restricting water permeability across the BBB, have important consequences on fluid hydrodynamics inside the BBB hereto inadequately recognized. Recent studies indicate that the mechanisms underlying brain water dynamics are distinct from systemic tissue water dynamics. Hydrostatic pressure created by the systolic force of the heart, essential for interstitial circulation and lymphatic flow in systemic circulation, is effectively impeded from propagating into the interstitial fluid inside the BBB by the tightly sealed endothelium of brain capillaries...
August 18, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28819685/cardiomyocyte-dimethylarginine-dimethylaminohydrolase-1-ddah1-plays-an-important-role-in-attenuating-ventricular-hypertrophy-and-dysfunction
#4
Xin Xu, Ping Zhang, Dongmin Kwak, John Fassett, Wenhui Yue, Dorothee Atzler, Xinli Hu, Xiaohong Liu, Huan Wang, Zhongbing Lu, Haipeng Guo, Edzard Schwedhelm, Rainer H Böger, Peijie Chen, Yingjie Chen
Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthases that limits nitric oxide bioavailability. Dimethylarginine dimethylaminohydrolase-1 (DDAH1) exerts a critical role for ADMA degradation and plays an important role in NO signaling. In the heart, DDAH1 is observed in endothelial cells and in the sarcolemma of cardiomyocytes. While NO signaling is important for cardiac adaptation to stress, DDAH1 impact on cardiomyocyte homeostasis is not clear. Here we used the MerCreMer-LoxP model to specifically disrupt cardiomyocyte DDAH1 expression in adult mice to determine the physiological impact of cardiomyocyte DDAH1 under basal conditions and during hypertrophic stress imposed by transverse aortic constriction (TAC)...
August 17, 2017: Basic Research in Cardiology
https://www.readbyqxmd.com/read/28819004/acute-oxygen-sensing-by-the-carotid-body-from-mitochondria-to-plasma-membrane
#5
Andy J Chang
Maintaining oxygen homeostasis is crucial to the survival of animals. Mammals respond acutely to changes in blood oxygen levels by modulating cardiopulmonary function. The major sensor of blood oxygen that regulates breathing is the carotid body (CB), a small chemosensory organ located at the carotid bifurcation. When arterial blood oxygen levels drop in hypoxia, neuroendocrine cells in the CB called glomus cells are activated to signal to afferent nerves that project to the brainstem. The mechanism by which hypoxia stimulates CB sensory activity has been the subject of many studies over the last 90 years...
August 17, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28818539/playing-a-rigged-game-inequality-s-effect-on-physiological-stress-responses
#6
Martin S Shapiro, Rhanda Rylant, Amanda de Lima, Andrea Vidaurri, Herman van de Werfhorst
High income and wealth inequality corresponds with high rates of various health and social problems. One possible factor that could be contributing to this correlation is stress experienced by those being treated unfairly in an unequal society. The present experiment attempted to simulate aspects of income inequality in a lab setting while recording several measures of stress. Participants (n=96) were assigned to one of four groups and played a memory game against a confederate opponent to earn "money" to spend in a lab market...
August 14, 2017: Physiology & Behavior
https://www.readbyqxmd.com/read/28818274/the-affection-of-the-disturbance-of-the-hydrodynamics-of-blood-in-case-of-stress-on-pathological-increase-of-level-of-low-density-lipoproteins-in-blood-the-formation-of-cylindrical-plaques-and-their-participation-in-the-development-of-acute-ischemic-disorders
#7
S E Rusanov
In this article is given the new insight about the affection of stress on the increase of level of low density lipoproteins (LDL) in the blood, which is connected with the disturbance of hydrodynamics in the bloodstream, the attention was paid to the cylindrical cholesterol plaque, and it's classification. The disturbance of hydrodynamics of blood under the stress leads to the formation of a cylindrical cholesterol plaque, which repeats the contour of the vessel, and leads to the ischemic disorders of the heart and brain...
September 2017: Medical Hypotheses
https://www.readbyqxmd.com/read/28818179/multiple-trauma-and-emergency-room-management
#8
Michael Frink, Philipp Lechler, Florian Debus, Steffen Ruchholtz
BACKGROUND: The care of severely injured patients remains a challenge. Their initial treatment in the emergency room is the essential link between first aid in the field and definitive in-hospital treatment. METHODS: We present important elements of the initial in-hospital care of severely injured patients on the basis of pertinent publications retrieved by a selective search in PubMed and the current German S3 guideline on the care of severely and multiply traumatized patients, which was last updated in 2016...
July 24, 2017: Deutsches Ärzteblatt International
https://www.readbyqxmd.com/read/28818144/refining-selection-for-elite-troops-by-predicting-military-training-outcome
#9
Susan Vrijkotte, Romain Meeusen, Bart Roelands, Sabine Kubesch, Olivier Mairesse, Guy de Schutter, Nathalie Pattyn
INTRODUCTION: Paratrooper training courses are very demanding, leading to a high number of drop-outs, despite existing selection criteria. This study investigated physiological, neuropsychological, and subjective data of completers and drop-outs during paratrooper training to identify potential predictive indices. METHODS: Tested were 24 paratrooper soldiers before (t0), after 8 wk (t1), and at the end of a 12-wk training camp (t2). There were 11 soldiers who completed the course and 13 dropped out...
September 1, 2017: Aerospace Medicine and Human Performance
https://www.readbyqxmd.com/read/28817701/effect-of-exoskeletal-joint-constraint-and-passive-resistance-on-metabolic-energy-expenditure-implications-for-walking-in-paraplegia
#10
Sarah R Chang, Rudi Kobetic, Ronald J Triolo
An important consideration in the design of a practical system to restore walking in individuals with spinal cord injury is to minimize metabolic energy demand on the user. In this study, the effects of exoskeletal constraints on metabolic energy expenditure were evaluated in able-bodied volunteers to gain insight into the demands of walking with a hybrid neuroprosthesis after paralysis. The exoskeleton had a hydraulic mechanism to reciprocally couple hip flexion and extension, unlocked hydraulic stance controlled knee mechanisms, and ankles fixed at neutral by ankle-foot orthoses...
2017: PloS One
https://www.readbyqxmd.com/read/28816745/restoration-of-normal-sympathetic-neural-function-in-heart-failure-following-baroreflex-activation-therapy-final-43-month-study-report
#11
Raffaella Dell'Oro, Edoardo Gronda, Gino Seravalle, Giuseppe Costantino, Luca Alberti, Barbara Baronio, Tiziana Staine, Emilio Vanoli, Giuseppe Mancia, Guido Grassi
BACKGROUND: Baroreflex activation therapy (BAT) exerts in severe heart failure sympathoinhibitory effects, improving clinical variables and reducing hospitalization rate. The current follow-up study was aimed at determining the long-term effects of BAT, assessing whether BAT in heart failure allows to restore physiological levels of sympathetic function. METHODS: Seven patients out of the 11 heart failure patients aged 66.5 ± 3 years (mean ± SEM) in New York Heart Association Class III with left ventricular ejection fraction 40% or less and impaired functional capacity recruited in the study survived at the final follow-up (43...
August 14, 2017: Journal of Hypertension
https://www.readbyqxmd.com/read/28816683/cardiorespiratory-model-based-data-driven-approach-for-sleep-apnea-detection
#12
Sandeep Gutta, Qi Cheng, Hoa Nguyen, Bruce Benjamin
Obstructive sleep apnea (OSA) is a chronic sleep disorder affecting millions of people worldwide. Individuals with OSA are rarely aware of the condition and are often left untreated, which can lead to some serious health problems. Nowadays, several low-cost wearable health sensors are available that can be used to conveniently and noninvasively collect a wide range of physiological signals. In this paper, we propose a new framework for OSA detection in which we combine the wearable sensor measurement signals with the mathematical models of the cardiorespiratory system...
August 14, 2017: IEEE Journal of Biomedical and Health Informatics
https://www.readbyqxmd.com/read/28816358/trpc3-mediated-ca-2-signals-as-a-promising-strategy-to-boost-therapeutic-angiogenesis-in-failing-hearts-the-role-of-autologous-endothelial-colony-forming-cells
#13
REVIEW
Francesco Moccia, Angela Lucariello, Germano Guerra
Endothelial progenitor cells (EPCs) are a sub-population of bone marrow-derived mononuclear cells that are released in circulation to restore damaged endothelium during its physiological turnover or rescue blood perfusion after an ischemic insult. Additionally, they may be mobilized from perivascular niches located within larger arteries' wall in response to hypoxic conditions. For this reason, EPCs have been regarded as an effective tool to promote revascularization and functional recovery of ischemic hearts, but clinical application failed to exploit the full potential of patients-derived cells...
August 17, 2017: Journal of Cellular Physiology
https://www.readbyqxmd.com/read/28815597/cardiac-action-potential-repolarization-re-visited-early-repolarization-shows-all-or-none-behaviour
#14
Beatriz Trenor, Karen Cardona, Javier Saiz, Denis Noble, Wayne Giles
In healthy mammalian hearts the action potential (AP) waveform initiates and modulates each contraction, or heartbeat. As a result, action potential height and duration are key physiological variables. In addition, rate-dependent changes in ventricular action potential duration (APD), and variations in APD at a fixed heart rate, are both reliable biomarkers of electrophysiological stability. Present guidelines for the likelihood that candidate drugs will increase arrhythmias rely on small changes in APD and Q-T intervals as criteria for Safety Pharmacology decisions...
August 17, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28814940/cardiac-health-knowledge-and-misconceptions-among-nursing-students-implications-for-nursing-curriculum-design
#15
Susan Ka Yee Chow, Yuen Yee Chan, Sin Kuen Ho, Ka Chun Ng
BACKGROUND: Cardiac misconceptions are common among healthcare professionals. The development of professional knowledge is considered an essential component of nursing education. Nurses, regardless of their grade, skills, and experience, should be updated with information so as to be able to rectify their misconceptions, as these could affect patient health outcomes. As the literature evaluating the cardiac knowledge and misconceptions of nursing students is sparse, a study of the subject seems warranted...
2017: BMC Nursing
https://www.readbyqxmd.com/read/28814807/psychological-impact-of-vehicle-exhaust-exposure-insights-from-an-animal-model
#16
Ankita Salvi, Gaurav Patki, Hesong Liu, Samina Salim
Air pollution resulting from exhaust emissions of vehicles has risen in the recent years, reportedly causing major adverse effects on the heart, lungs and the brain. Though respiratory and cardiovascular effects of these emissions are well identified, psychological and neurobiological complications of prolonged exposure to vehicle emissions remain unknown. Pro-oxidants are considered as major constituents of vehicle emissions. This is important considering causal link between oxidative stress and behavioral and cognitive impairments...
August 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28814736/emotions-alter-muscle-proprioceptive-coding-of-movements-in-humans
#17
Rochelle Ackerley, Jean-Marc Aimonetti, Edith Ribot-Ciscar
Emotions can evoke strong reactions that have profound influences, from gross changes in our internal environment to small fluctuations in facial muscles, and reveal our feelings overtly. Muscles contain proprioceptive afferents, informing us about our movements and regulating motor activities. Their firing reflects changes in muscle length, yet their sensitivity can be modified by the fusimotor system, as found in animals. In humans, the sensitivity of muscle afferents is modulated by cognitive processes, such as attention; however, it is unknown if emotional processes can modulate muscle feedback...
August 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28814710/left-univentricular-pacing-by-rate-adaptive-atrioventricular-delay-in-treatment-of-chronic-heart-failure
#18
Lulu Zhao, Ling Zhao, Lijin Pu, Baotong Hua, Yu Wang, Shumin Li, Qing Li, Tao Guo
BACKGROUND Cardiac resynchronization therapy (CRT) is efficacious in the treatment of chronic heart failure (CHF); however, because it is non-physiological, some patients are unresponsive. The present study used rate-adaptive atrioventricular delay (RAAVD) to track the physiological atrioventricular delay and investigated the effects of left univentricular pacing on CRT. MATERIAL AND METHODS Patients with CHF fulfilling the indication of CRT Class I were categorized into a left univentricular pacing by RAAVD group and a standard biventricular pacing group...
August 17, 2017: Medical Science Monitor: International Medical Journal of Experimental and Clinical Research
https://www.readbyqxmd.com/read/28814575/prenatal-environment-affects-embryonic-response-to-song
#19
Diane Colombelli-Négrel, Sonia Kleindorfer
Early environmental enrichment improves postnatal cognition in animals and humans. Here, we examined the effects of the prenatal acoustic environment (parental song rate) on prenatal attention in superb fairy-wren (Malurus cyaneus) embryos, the only songbird species with evidence of prenatal discrimination of maternal calls and in ovo call learning. Because both adults also sing throughout the incubation phase, we broadcast songs to embryos and measured their heart rate response in relation to parental song rate and tutor identity (familiarity, sex)...
August 2017: Biology Letters
https://www.readbyqxmd.com/read/28813842/using-wearable-physiological-sensors-to-predict-energy-expenditure
#20
Kimberly A Ingraham, Daniel P Ferris, C David Remy
Lower-limb assistive robotic devices are often evaluated by measuring a reduction in the user's energy cost. Using indirect calorimetry to estimate energy cost is poorly suited for real-time estimation and long-term collection. The goal of this study was to use data from wearable sensors to predict energy cost with better temporal resolution and less variability than breath measurements. We collected physiological data (heart rate, electrodermal activity, skin temperature) and mechanical data (EMG, accelerometry) from three healthy subjects walking on a treadmill at various speeds on level ground, inclined, and backwards...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
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