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Oxygen consumption

Marty D Spranger, Jasdeep Kaur, Javier A Sala-Mercado, Abhinav C Krishnan, Rania Abu-Hamdah, Alberto Alvarez, Tiago M Machado, Robert A Augustyniak, Donal S O'Leary
Increases in myocardial oxygen consumption during exercise mainly occur via increases in coronary blood flow (CBF) as cardiac oxygen extraction is high even at rest. However, sympathetic coronary constrictor tone can limit increases in CBF. Increased sympathetic nerve activity (SNA) during exercise is, in part, a function of muscle metaboreflex activation (MMA). As SNA is heightened even at rest in subjects with hypertension (HTN), we tested whether HTN causes exaggerated coronary vasoconstriction during mild treadmill exercise with MMA (elicited by reducing hindlimb blood flow by ~60%) thereby limiting increases in CBF and ventricular performance...
October 21, 2016: American Journal of Physiology. Heart and Circulatory Physiology
S Lühl, H Bode, W Schlötzer, M Bartsakoulia, R Horvath, A Abicht, M Stenzel, J Kirschner, S C Grünert
BACKGROUND: Pontocerebellar hypoplasia type 6 (PCH6) is a mitochondrial disease caused by mutations in the RARS2 gene. RARS2 encodes mitochondrial arginyl transfer RNA synthetase, an enzyme involved in mitochondrial protein translation. A total of 27 patients from 14 families have been reported so far. Characteristic clinical features comprise neonatal lactic acidosis, severe encephalopathy, intractable seizures, feeding problems and profound developmental delay. Most patients show typical neuroradiologic abnormalities including cerebellar hypoplasia and progressive pontocerebellar atrophy...
October 21, 2016: Orphanet Journal of Rare Diseases
Haiying Quan, Wenrui Hao, Lu Li, Ming Sun, Kuan Zhang
The whole-room indirect calorimeter is considered as important equipment for human energy expenditure measurement, but noise reduction in the system remains a challenge. A selective filtering method (SFM) was designed to improve the accuracy of the computation of O2 consumption rate ([Formula: see text]) and CO2 production rate ([Formula: see text]), based on two facts: (1) the rapid changes of [Formula: see text], [Formula: see text] and respiratory quotient (RQ) in human should be accompanied by physical activity; (2) the oxygen consumption and the carbon dioxide production should not be negative because living humans do not generate oxygen, nor consume carbon dioxide...
October 20, 2016: Medical & Biological Engineering & Computing
Cosmo Godino, Antonio Colombo, Alberto Margonato
Heart rate is an established prognostic marker for longevity and is an important contributor in the pathophysiology of various cardiovascular diseases, including ischemic heart disease and heart failure. Most ischemic episodes are triggered by an increase in heart rate, which causes an imbalance between myocardial oxygen delivery and consumption. In addition, increased heart rate is a modifiable risk factor for chronic heart failure. Ivabradine, an inhibitor of If ion channels, is an approved second-line anti-ischemic drug for the treatment of angina...
October 21, 2016: Clinical Drug Investigation
Min Joo Kim, Young Do Koo, Min Kim, Soo Lim, Young Joo Park, Sung Soo Chung, Hak C Jang, Kyong Soo Park
BACKGROUND: Panax ginseng has glucose-lowering effects, some of which are associated with the improvement in insulin resistance in skeletal muscle. Because mitochondria play a pivotal role in the insulin resistance of skeletal muscle, we investigated the effects of the ginsenoside Rg3, one of the active components of P. ginseng, on mitochondrial function and biogenesis in C2C12 myotubes. METHODS: C2C12 myotubes were treated with Rg3 for 24 hours. Insulin signaling pathway proteins were examined by Western blot...
October 2016: Diabetes & Metabolism Journal
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
Kurt A Escobar, Jacobo Morales, Trisha A Vandusseldorp
CrossFit is a metabolically demanding strength and conditioning method which performance may benefit from a carbohydrate (CHO)-rich diet. This study investigated the effect of three consecutive days of high CHO intake on CrossFit performance and corresponding metabolically -related variables in strength trained individuals. Eighteen subjects with a CHO intake of <6 g/kg/day were randomly assigned into a CHO (n = 9) or control (C) group (n =9) and underwent a 9-day training protocol. During days 1, 5, and 9, performance was measured as repetitions completed during a 12 minute CrossFit workout...
2016: International Journal of Exercise Science
Alexander N Shikov, Olga N Pozharitskaya, Valery G Makarov
PURPOSE: Aralia elata var. mandshurica (Rupr. & Maxim.) J.Wen syn. A. mandshurica Rupr. & Maxim is evaluated for its medicinal application. The aim of this study is to analyze pharmacological studies on A. elata var. mandshurica published until December 2015. METHODS: The information regarding the chemistry, safety, effectiveness, and pharmacological and clinical effects of A. elata was systematically collected from the scientific literature through library catalogs; online services such as E-library...
November 15, 2016: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
Nina Lefeber, Eva Swinnen, Eric Kerckhofs
PURPOSE: The integration of sufficient cardiovascular stress into robot-assisted gait (RAG) training could combine the benefits of both RAG and aerobic training. The aim was to summarize literature data on the immediate effects of RAG compared to walking without robot-assistance on metabolic-, cardiorespiratory- and fatigue-related parameters. METHODS: PubMed and Web of Science were searched for eligible articles till February 2016. Means, SDs and significance values were extracted...
October 20, 2016: Disability and Rehabilitation. Assistive Technology
O R Vaughan, A L Fowden
The placenta is a dynamic, metabolically active organ with significant nutrient and energy requirements for growth, nutrient transfer and protein synthesis. It uses a range of substrates to meet its energy needs and has a higher rate of oxygen (O2 ) consumption than many other foetal and adult tissues. Placental metabolism varies with species and alters in response to a range of nutritional and endocrine signals of adverse environmental conditions. The placenta integrates these signals and adapts its metabolic phenotype to help maintain pregnancy and to optimize offspring fitness by diversifying the sources of carbon and nitrogen available for energy production, hormone synthesis and foeto-placental growth...
October 2016: Reproduction in Domestic Animals, Zuchthygiene
April Hayward, Mariela Pajuelo, Catherine G Haase, David M Anderson, James F Gillooly
Dive duration in air-breathing vertebrates is thought to be constrained by the volume of oxygen stored in the body and the rate at which it is consumed (i.e., "oxygen store/usage hypothesis"). The body mass-dependence of dive duration among endothermic vertebrates is largely supportive of this model, but previous analyses of ectothermic vertebrates show no such body mass-dependence. Here we show that dive duration in both endotherms and ectotherms largely support the oxygen store/usage hypothesis after accounting for the well-established effects of temperature on oxygen consumption rates...
2016: PeerJ
Raoyrin Chanavirut, Pattarapong Makarawate, Ian A Macdonald, Naruemon Leelayuwat
BACKGROUND: Imbalances of the autonomic nervous (ANS), the cardiovascular system, and ionics might contribute to the manifestation of The Brugada Syndrome (BrS). Thus, this study has aimed to investigate the cardio-respiratory fitness and the responses of the ANS both at rest and during a sub-maximal exercise stress test, in BrS patients and in gender-matched and age-matched healthy sedentary controls. METHODS: Eleven BrS patients and 23 healthy controls were recruited in Khon Kaen, Thailand...
October 2016: Journal of Arrhythmia
Mª Del Mar Blanquer-Rosselló, Reyniel Hernández-López, Pilar Roca, Jordi Oliver, Adamo Valle
BACKGROUND: The polyphenol resveratrol (RSV) is found in the skin of red grapes and has been reported to exhibit anticancer properties. The antitumor effects of RSV in the gastrointestinal tract have gained considerable interest due to the high exposure of this tissue to this dietary compound. One of the hallmarks of cancer cells is their particular metabolism mainly relying on glycolysis for ATP production rather than mitochondrial oxidative phosphorylation. Although RSV has been described to act as a calorie-restriction mimetic, modulating energy metabolism in normal tissues, little efforts have been done to study the effects of this polyphenol in the metabolism of cancer cells...
October 17, 2016: Biochimica et Biophysica Acta
Charles M Watson, Warren W Burggren
Three congeneric lizards from the southeastern United States (Plestiodon fasciatus, P. inexpectatus, and P. laticeps) exhibit a unique nested distribution. All three skink species inhabit the US Southeast, but two extend northward to central Ohio (P. fasciatus and P. laticeps) and P. fasciatus extends well into Canada. Distinct interspecific differences in microhabitat selection and behavior are associated with the cooler temperatures of the more Northern ranges. We hypothesized that interspecific differences in metabolic temperature sensitivity locally segregates them across their total range...
2016: PloS One
Jin-Rong Huo, Xiao-Xu Wang, Lu Li, Hai-Xia Cheng, Yan-Jing Su, Ping Qian
This paper reports a study of the electronic properties, structural stability and catalytic activity of the W13@Pt42 core-shell structure using the First-principles calculations. The degree of corrosion of W13@Pt42 core-shell structure is simulated in acid solutions and through molecular absorption. The absorption energy of OH for this structure is lower than that for Pt55, which inhibits the poison effect of O containing intermediate. Furthermore we present the optimal path of oxygen reduction reaction catalyzed by W13@Pt42...
October 19, 2016: Scientific Reports
Andrea J Morash, Sara R C Mackellar, Louise Tunnah, David A Barnett, Kilian M Stehfest, Jayson M Semmens, Suzanne Currie
Estuarine habitats are frequently used as nurseries by elasmobranch species for their protection and abundant resources; however, global climate change is increasing the frequency and severity of environmental challenges in these estuaries that may negatively affect elasmobranch physiology. Hyposmotic events are particularly challenging for marine sharks that osmoconform, and species-specific tolerances are not well known. Therefore, we sought to determine the effects of an acute (48 h) ecologically relevant hyposmotic event (25...
2016: Conservation Physiology
Horrolein Arab, Soleiman Mahjoub, Karimollah Hajian-Tilaki, Mehdi Moghadasi
BACKGROUND: Alzheimer's disease (AD) is the most prevalent degenerative disorder of the brain among elderly individuals. Many studies indicate that oxidative stress is an important pathogenic factor which involves oxidizing macromolecules such as DNA, lipids, and proteins in AD. Green tea is a rich source of antioxidant compounds that can remove radical oxygen species. The purpose of this study was to investigate the influence of green tea consumption on markers of oxidative stress in AD...
2016: Caspian Journal of Internal Medicine
Samina Salim
Biochemical integrity of the brain is vital for normal functioning of the central nervous system (CNS). One of the contributing factors of cerebral biochemical impairment is a chemical process called oxidative stress. Oxidative stress occurs upon excessive free radical production due to insufficiency of counteracting antioxidant response system. The brain with its high oxygen consumption and lipid-rich content is highly susceptible to oxidative stress. Therefore, oxidative stress-induced damage to the brain has a strong potential to negatively impact normal CNS functions...
October 17, 2016: Journal of Pharmacology and Experimental Therapeutics
James C Boyett, Gabrielle E W Giersch, Christopher J Womack, Michael J Saunders, Christine A Hughey, Hannah M Daley, Nicholas D Luden
This project was designed to assess the effects of time of day and training status on the benefits of caffeine supplementation for cycling performance. Twenty male subjects (Age, 25 years; Peak oxygen consumption, 57 mL·kg(-1)·min(-1)) were divided into tertiles based on training levels, with top and bottom tertiles designated as 'trained' (n = 7) and 'untrained' (n = 7). Subjects completed two familiarization trials and four experimental trials consisting of a computer-simulated 3-km cycling time trial (TT)...
October 14, 2016: Nutrients
Yuanting Cui, Li Li, Peng Gao, Liqun Ma, Daoyan Liu, Zhiming Zhu
OBJECTIVE: Obesity is global healthy problem. Uncoupling protein 1 (UCP1) mainly expresses on brown adipose tissue (BAT), uncouples energy substrate oxidation from mitochondrial ATP production and results in the loss of potential energy as heat. Transient receptor potential vanilloid subfamily, member 1 (TRPV1) is the heat-gated cation ion channel. The aim of this study was to investigate the in vivo role of TRPV1 and UCP1 co-action in obesity. DESIGN AND METHOD: We generated and characterized UCP1 mice lacking TRPV1 activity (TRPV1/UCP1 mice)...
September 2016: Journal of Hypertension
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