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Heart physiology

Matthew E Dupre, Alicia Nelson
Heart disease is the leading cause of death in the United States and nearly one million Americans will have a heart attack this year. Although the risks associated with a heart attack are well established, we know surprisingly little about how marital factors contribute to survival in adults afflicted with heart disease. This study uses a life course perspective and longitudinal data from the Health and Retirement Study to examine how various dimensions of marital life influence survival in U.S. older adults who suffered a heart attack (n = 2197)...
October 15, 2016: Social Science & Medicine
Wilfried Dinh, Barbara Albrecht-Küpper, Mihai Gheorghiade, Adriaan A Voors, Michael van der Laan, Hani N Sabbah
Adenosine exerts a variety of physiological effects by binding to cell surface G-protein-coupled receptor subtypes, namely, A1, A2a, A2b, and A3. The central physiological role of adenosine is to preclude tissue injury and promote repair in response to stress. In the heart, adenosine acts as a cytoprotective modulator, linking cardiac function to metabolic demand predominantly via activation of adenosine A1 receptors (A1Rs), which leads to inhibition of adenylate cyclase activity, modulation of protein kinase C, and opening of ATP-sensitive potassium channels...
October 22, 2016: Handbook of Experimental Pharmacology
Camilla T Damsgaard, Lotte Lauritzen, Hanne Hauger, Stine Vuholm, Marie N Teisen, Christian Ritz, Max Hansen, Janni Niclasen, Christian Mølgaard
BACKGROUND: Most children in Western populations do not meet recommendations for fish consumption. Oily fish is an important source of n-3 long-chain polyunsaturated fatty acids (LCPUFA), which reduce blood pressure and plasma triacylglycerol in adults and may affect cognitive development and behavior. However, to our knowledge, the potential effects of oily fish on cardiometabolic health, cognitive function, and behavior in children have not been investigated. The aim of the FiSK Junior study is to investigate the effects of oily fish consumption on cardiovascular risk markers, cognitive function, and behavior in healthy children...
October 21, 2016: Trials
Annika Clamor, Julian Koenig, Julian F Thayer, Tania M Lincoln
Arousal and the way it is coped with are relevant to the emergence of psychotic symptoms. Heart rate variability (HRV) stems from autonomic responses to environmental demands such as stress and is an index of physiological arousal, adaptability, and homeostatic reflexes forming autonomic balance. A randomized-controlled between-subjects trial that compared HRV-biofeedback (BF) to an active relaxation and to a waiting control condition was conducted in a sample with attenuated subclinical psychotic symptoms (N = 84)...
October 11, 2016: Behaviour Research and Therapy
Derek Nelson, Rachael M Heuer, Georgina K Cox, John D Stieglitz, Ronald Hoenig, Edward M Mager, Daniel D Benetti, Martin Grosell, Dane A Crossley
Exposure to polycyclic aromatic hydrocarbons (PAH) negatively impacts exercise performance in fish species but the physiological modifications that result in this phenotype are poorly understood. Prior studies have shown that embryonic and juvenile mahi-mahi (Coryphaeus hippurus) exposed to PAH exhibit morphological abnormalities, altered cardiac development and reduced swimming performance. It has been suggested that cardiovascular function inhibited by PAH exposure accounts for the compromised exercise performance in fish species...
October 14, 2016: Aquatic Toxicology
Daniel J Peart, Andy Hensby, Matthew P Shaw
The purpose of this study was to compare markers of hydration during sub-maximal exercise and subsequent time trial performance when consuming water (PW) or coconut water (CW). There was also a secondary aim to assess the palatability of CW during exercise and voluntary intake during intense exercise. 10 males (age 27.9 + 4.9 years, body mass 78.1 + 10.1kg, average max minute power 300.2 + 28.2W) completed 60-min of sub-maximal cycling followed by a 10-km time trial on two occasions. During these trials participants consumed either PW or CW in a randomised manner, drinking a 250 ml of the assigned drink between 10-15 min, 25-30 min and 40-45 min, and then drinking ad libitum from 55-min until the end of the time trial...
October 21, 2016: International Journal of Sport Nutrition and Exercise Metabolism
Riccardo Toninato, Silvia Scuri, Vincenzo Tarzia, Gino Gerosa, Francesca M Susin
PURPOSE: The gold standard therapy for patients with advanced heart failure is heart transplant. The gap between donors and patients in waiting lists promoted the development of circulatory support devices, such as the total artificial heart (TAH). Focusing on in vitro tests performed with CardioWest™ TAH (CW) driven by the SynCardia Freedom® portable driver (FD) the present study goals are: i) prove the reliability of a hydraulic circuit used as patient simulator to replicate a quasi-physiological scenario for various hydrodynamic conditions, ii) investigate the hydrodynamic performance of the CW FD, iii) help clinicians in possible interpretation of clinical cases outcomes...
October 15, 2016: International Journal of Artificial Organs
Walter H Reinhart
The hematocrit (Hct) determines the oxygen carrying capacity of blood, but also increases blood viscosity and thus flow resistance. From this dual role the concept of an optimum Hct for tissue oxygenation has been derived. Viscometric studies using the ratio Hct/blood viscosity at high shear rate showed an optimum Hct of 50-60% for red blood cell (RBC) suspensions in plasma. For the perfusion of an artificial microvascular network with 5-70μm channels the optimum Hct was 60-70% for high driving pressures. With lower shear rates or driving pressures the optimum Hct shifted towards lower values...
October 21, 2016: Clinical Hemorheology and Microcirculation
Joseph M Blankush, Robbie Freeman, Joy McIlvaine, Trung Tran, Stephen Nassani, I Michael Leitman
Modified Early Warning Scores (MEWS) provide real-time vital sign (VS) trending and reduce ICU admissions in post-operative patients. These early warning calculations classically incorporate oxygen saturation, heart rate, respiratory rate, systolic blood pressure, and temperature but have not previously included end-tidal CO2 (EtCO2), more recently identified as an independent predictor of critical illness. These systems may be subject to failure when physiologic data is incorrectly measured, leading to false alarms and increased workload...
October 20, 2016: Journal of Clinical Monitoring and Computing
Lois Choy, Jie Ming Yeo, Vivian Tse, Shing Po Chan, Gary Tse
The mouse is the second mammalian species, after the human, in which substantial amount of the genomic information has been analyzed. With advances in transgenic technology, mutagenesis is now much easier to carry out in mice. Consequently, an increasing number of transgenic mouse systems have been generated for the study of cardiac arrhythmias in ion channelopathies and cardiomyopathies. Mouse hearts are also amenable to physical manipulation such as coronary artery ligation and transverse aortic constriction to induce heart failure, radiofrequency ablation of the AV node to model complete AV block and even implantation of a miniature pacemaker to induce cardiac dyssynchrony...
September 2016: IJC Heart & Vasculature
Débora Claësson, Tobias Wang, Hans Malte
Global warming results in increasing water temperature, which may represent a threat to aquatic ectotherms. The rising temperature affects ecology through physiology, by exerting a direct limiting effect on the individual. The mechanism controlling individual thermal tolerance is still elusive, but some evidence shows that the heart plays a central role, and that insufficient transport of oxygen to the respiring tissues may determine the thermal tolerance of animals. In this study, the influence of the heart in thermal limitation was investigated by measurements of aerobic scope in the European eel (Anguilla anguilla) together with measurements of cardiac output during rest and activity...
2016: Conservation Physiology
Victor M Niemeijer, Ruud F Spee, Thijs Schoots, Pieter F F Wijn, Hareld M Kemps
The extent and speed of transient skeletal muscle deoxygenation during exercise onset in chronic heart failure (CHF) patients is related to impairments of local O2 delivery and utilization. This study examined the physiological background of submaximal exercise performance in 19 moderately impaired CHF patients (Weber class A, B, and C) compared with 19 matched healthy control (HC) subjects by measuring skeletal muscle oxygenation (SmO2) changes during cycling exercise. All subjects performed two subsequent moderate-intensity 6-minute exercise tests (bout 1 and 2) with measurements of pulmonary oxygen uptake kinetics, and SmO2 using near infrared (NIR) spatially resolved spectroscopy (SRS) at the vastus lateralis for determination of absolute oxygenation values, amplitudes, kinetics (mean response time for onset), and deoxygenation overshoot characteristics...
October 7, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Aart Mookhoek, Kapil Krishnan, Sam Chitsaz, Heide Kuang, Liang Ge, Paul H Schoof, Ad J J C Bogers, Johanna J M Takkenberg, Elaine E Tseng
BACKGROUND: Progressive autograft dilatation after a Ross operation suggests that remodeling does not effectively reproduce native aortic root biomechanics. In the first of this two-part series, we compared mechanical properties of explanted autografts to pulmonary roots at pulmonary pressures. The goal of this study was to compare mechanical properties of explanted autografts to native aortic roots at systemic pressures. METHODS: Autograft specimens were obtained from patients undergoing reoperation after Ross operation...
October 17, 2016: Annals of Thoracic Surgery
Rosario Scarfone, Antonio Ammendolia
BACKGROUND: The aim of this study was to investigate the physiological demands and technical-tactical performances of field players in Italian elite beach soccer team. METHODS: Three official matches of the Italian First Division beach soccer tournament were analyzed to evaluate the heart rate (HR) and time-motion analysis considering: standing, walking, jogging, running and sprinting, and technical-tactical aspects. Repeated-measures ANOVAs were used to determine the effects of time on the physiological measures and time motion analysis...
October 20, 2016: Journal of Sports Medicine and Physical Fitness
Luigi Baciadonna, Christian Nawroth, Alan G McElligott
Animal emotional states can be investigated by evaluating their impact on cognitive processes. In this study, we used a judgement bias paradigm to determine if short-term positive human-animal interaction (grooming) induced a positive affective state in goats. We tested two groups of goats and trained them to discriminate between a rewarded and a non-rewarded location over nine training days. During training, the experimental group (n = 9) was gently groomed by brushing their heads and backs for five min over 11 days (nine training days, plus two testing days, total time 55 min)...
2016: PeerJ
BongKyoo Choi, SangJun Choi, JeeYeon Jeong, JiWon Lee, Shi Shu, Nu Yu, SangBaek Ko, Yifang Zhu
BACKGROUND: Few studies have examined ambulatory cardiovascular physiological parameters of taxi drivers while driving in relation to their occupational hazards. This study aims to investigate and quantify the impact of worksite physical hazards as a whole on ambulatory heart rate of professional taxi drivers while driving without their typical worksite psychosocial stressors. METHODS: Ambulatory heart rate (HRdriving) of 13 non-smoking male taxi drivers (24 to 67 years old) while driving was continuously assessed on their 6-hour experimental on-road driving in Los Angeles...
2016: Annals of Occupational and Environmental Medicine
Hanna Gustafsson, Colleen Doyle, Michelle Gilchrist, Elizabeth Werner, Catherine Monk
The consequences of childhood maltreatment are profound and long lasting. Not only does the victim of abuse suffer as a child, but there is mounting evidence that a history of maltreatment places the next generation at risk for significant psychopathology. Research identifies postnatal factors as affecting this intergenerational transmission of trauma. However, emerging evidence suggests that part of this risk may be transmitted before birth, passed on via abuse-related alterations in the in utero environment that are as yet largely unidentified...
October 20, 2016: Development and Psychopathology
Pedro M D Agrícola, Daniel G da Silva Machado, Luiz F de Farias Junior, Luiz I do Nascimento Neto, André I Fonteles, Samara K A da Silva, Cheng H N Chao, Eduardo B Fontes, Hassan M Elsangedy, Alexandre H Okano
Pleasure plays a key role in exercise behavior. However, the influence of cycling cadence needs to be elucidated. Here, we verified the effects of cycling cadence on affect, perceived exertion (ratings of perceived exertion), and physiological responses. In three sessions, 15 men performed a maximal cycling incremental test followed by two 30-min constant workload (50% of peak power) bouts at 60 and 100 r/min. The pleasure was higher when participants cycled at 60 r/min, whereas ratings of perceived exertion, heart rate, and oxygen uptake were lower (p < ...
October 17, 2016: Perceptual and Motor Skills
Attila Oláh, Dalma Kellermayer, Csaba Mátyás, Balázs Tamás Németh, Árpád Lux, Lilla Szabó, Marianna Török, Mihály Ruppert, Anna Meltzer, Alex Ali Sayour, Kálmán Benke, István Hartyánszky, Béla Merkely, Tamás Radovits
PURPOSE: Long-term exercise training is associated with characteristic cardiac adaptation, termed athlete's heart. Our research group previously characterized in vivo left ventricular (LV) function of exercise-induced cardiac hypertrophy in detail in a rat model, however the effect of detraining on LV function is still unclear. We aimed at evaluating the reversibility of functional alterations of athlete's heart after detraining. METHODS: Rats (n=16) were divided into detrained exercised (DEx) and detrained control (DCo) groups...
October 14, 2016: Medicine and Science in Sports and Exercise
Keisuke Shinohara, Xuebo Liu, Donald A Morgan, Deborah R Davis, Maria Luisa S Sequeira-Lopez, Martin D Cassell, Justin L Grobe, Kamal Rahmouni, Curt D Sigmund
The renin-angiotensin system (RAS) in the brain is a critical determinant of blood pressure, but the mechanisms regulating RAS activity in the brain remain unclear. Expression of brain renin (renin-b) occurs from an alternative promoter-first exon. The predicted translation product is a nonsecreted enzymatically active renin whose function is unknown. We generated a unique mouse model by selectively ablating the brain-specific isoform of renin (renin-b) while preserving the expression and function of the classical isoform expressed in the kidney (renin-a)...
October 17, 2016: Hypertension
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