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"Oxygen kinetics"

Simon Fryer, David Giles, Inmaculada Garrido Palomino, Alejandro de la O Puerta, Vanesa España Romero
Rock climbing performance has been suggested to involve a notable contribution from the aerobic metabolism. Previously it has been shown that forearm oxygenation kinetics can be used to distinguish ability groups and predict red-point sport climbing performance. Currently it is not known if forearm oxygenation kinetics, or a sport specific assessment of cardiorespiratory fitness best predicts sport rock climbing performance. The aim of the study was to determine whether forearm oxidative capacity index, maximal de-oxygenation (Δ score) during a treadwall V[Combining Dot Above]O[SUBSCRIPT TWO]peak test, treadwall V[Combining Dot Above]O[SUBSCRIPT TWO]peak, or running V[Combining Dot Above]O[SUBSCRIPT TWO]max best predicts self-reported sport climbing performance...
March 13, 2017: Journal of Strength and Conditioning Research
Ilias Smilios, Aristides Myrkos, Andreas Zafeiridis, Argyris Toubekis, Apostolos Spassis, Savas P Tokmakidis
The recovery duration and the work to recovery ratio are important aspects to consider when designing a high-intensity aerobic interval exercise (HIIE). This study examined the effects of recovery duration on total exercise time performed above 80, 90 and 95% of maximum oxygen consumption (VO2max) and heart rate (HRmax) during a single-bout HIIE. We also evaluated the effects on VO2 and HR kinetics, blood lactate concentration and rating of perceived exertion (RPE). Eleven moderately trained males (22.1±1 yrs...
March 13, 2017: Journal of Strength and Conditioning Research
Sadamitsu Yoshida, Hitoshi Adachi, Makoto Murata, Junichi Tomono, Shigeru Oshima, Masahiko Kurabayashi
BACKGROUND: Myocardial ischemia induces cardiac dysfunction, resulting in insufficient oxygen supply to peripheral tissues and mismatched energy production during exercise. To relieve the insufficient oxygen supply, heart rate (HR) response is augmented; however, beta-adrenergic receptor blockers (BB) restrict HR response. Although BB are essential drugs for angina pectoris, the effect of BB on exercise tolerance in patients with angina has not been studied. The aim of this study was to clarify the importance of HR augmentation to preserve exercise tolerance in patients with angina pectoris...
March 7, 2017: Journal of Cardiology
Nuno Casanova, Joana F Reis, João R Vaz, Rita Machado, Bruno Mendes, Duane C Button, Pedro Pezarat-Correia, Sandro R Freitas
Two experiments (n = 10) were conducted to determine the effects of roller massager (RM) on ankle plantar flexor muscle recovery after exercise-induced muscle damage (EIMD). Experiment 1 examined both functional [i.e., ankle plantar flexion maximal isometric contraction and submaximal (30%) sustained force; ankle dorsiflexion maximal range of motion and resistance to stretch; and medial gastrocnemius pain pressure threshold] and morphological [cross-sectional area, thickness, fascicle length, and fascicle angle] variables, before and immediately, 1, 24, 48, and 72 h after an EIMD stimulus...
January 18, 2017: Journal of Sports Sciences
Wendell W Walters, Greg Michalski
Ab initio calculations have been carried out to investigate nitrogen (k(15)/k(14)) and position-specific oxygen (k(17)/k(16)O & k(18)/k(16)) kinetic isotope effects (KIEs) for the reaction between NO and O3 using CCSD(T)/6-31G(d) and CCSD(T)/6-311G(d) derived frequencies in the complete Bigeleisen equations. Isotopic enrichment factors are calculated to be -6.7‰, -1.3‰, -44.7‰, -14.1‰, and -0.3‰ at 298 K for the reactions involving the (15)N(16)O, (14)N(18)O, (18)O(16)O(16)O, (16)O(18)O(16)O, and (16)O(16)O(18)O isotopologues relative to the 14N(16)O and 16O3 isotopologues, respectively (CCSD(T)/6-311G(d))...
December 14, 2016: Journal of Chemical Physics
Stuart B Hooper, Kelly J Crossley, Valerie A Zahra, Jeroen van Vonderen, Alison Moxham, Andrew W Gill, Martin Kluckow, Arjan B Te Pas, Euan M Wallace, Graeme R Polglase
OBJECTIVE: While delayed umbilical cord clamping (UCC) is thought to facilitate placental to infant blood transfusion, the physiological factors regulating flow in the umbilical arteries and veins during delayed UCC is unknown. We investigated the effects of gravity, by changing fetal height relative to the placenta, and ventilation on umbilical blood flows and the cardiovascular transition during delayed UCC at birth. METHODS: Catheters and flow probes were implanted into preterm lambs (128 days) prior to delivery to measure pulmonary, carotid, umbilical artery (UaBF) and umbilical venous (UvBF) blood flows...
November 8, 2016: Archives of Disease in Childhood. Fetal and Neonatal Edition
James G Hopker, Giuseppe Caporaso, Andrea Azzalin, Roger Carpenter, Samuele M Marcora
The [Formula: see text] slow component ([Formula: see text]) that develops during high-intensity aerobic exercise is thought to be strongly associated with locomotor muscle fatigue. We sought to experimentally test this hypothesis by pre-fatiguing the locomotor muscles used during subsequent high-intensity cycling exercise. Over two separate visits, eight healthy male participants were asked to either perform a non-metabolically stressful 100 intermittent drop-jumps protocol (pre-fatigue condition) or rest for 33 min (control condition) according to a random and counterbalanced order...
2016: Frontiers in Physiology
Fangyao Hu, Karthik Vishwanath, Joseph K Salama, Alaattin Erkanli, Bercedis Peterson, James R Oleson, Walter T Lee, David M Brizel, Nimmi Ramanujam, Mark W Dewhirst
PURPOSE: To test whether oxygenation kinetics correlate with the likelihood for local tumor control after fractionated radiation therapy. METHODS AND MATERIALS: We used diffuse reflectance spectroscopy to noninvasively measure tumor vascular oxygenation and total hemoglobin concentration associated with radiation therapy of 5 daily fractions (7.5, 9, or 13.5 Gy/d) in FaDu xenografts. Spectroscopy measurements were obtained immediately before each daily radiation fraction and during the week after radiation therapy...
October 1, 2016: International Journal of Radiation Oncology, Biology, Physics
Scott L Hummel, John Herald, Craig Alpert, Kimberlee A Gretebeck, Wendy S Champoux, Donald R Dengel, Peter V Vaitkevicius, Neil B Alexander
BACKGROUND: Submaximal oxygen uptake measures are more feasible and may better predict clinical cardiac outcomes than maximal tests in older adults with heart failure (HF). We examined relationships between maximal oxygen uptake, submaximal oxygen kinetics, functional mobility, and physical activity in older adults with HF and reduced ejection fraction. METHODS: Older adults with HF and reduced ejection fraction (n = 25, age 75 ± 7 years) were compared to 25 healthy age- and gender-matched controls...
July 2016: Journal of Geriatric Cardiology: JGC
K Dipla, E Kintiraki, I Grigoriadou, G Triantafyllou, A Triantafyllou, I Zografou, I S Vrabas, A Zafeiridis, D G Goulis, S Douma
OBJECTIVE: Patients with Gestational diabetes mellitus (GDM) are at increased risk for gestational hypertension. Although GDM is considered a mild metabolic dysfunction, some studies have associated GDM with alterations of endothelial responsiveness, whereas, other studies suggested that the time of exposure to hyperglycemia might be insufficient to induce micro- and macrovascular dysfunction. Near-infrared spectroscopy (NIRS) allows a non-invasive monitoring of functional changes in oxygenated hemoglobin (O2Hb) and oxygen tissue saturation (TSI) and the assessment of microvascular function within the skeletal muscle...
September 2016: Journal of Hypertension
Alexandre Super, Nicolas Jaccard, Marco Paulo Cardoso Marques, Rhys Jarred Macown, Lewis Donald Griffin, Farlan Singh Veraitch, Nicolas Szita
Oxygen plays a key role in stem cell biology as a signaling molecule and as an indicator of cell energy metabolism. Quantification of cellular oxygen kinetics, i.e. the determination of specific oxygen uptake rates (sOURs), is routinely used to understand metabolic shifts. However current methods to determine sOUR in adherent cell cultures rely on cell sampling, which impacts on cellular phenotype. We present real-time monitoring of cell growth from phase contrast microscopy images, and of respiration using optical sensors for dissolved oxygen...
September 2016: Biotechnology Journal
David Giles, Vanesa España Romero, Inmaculada Garrido, Alejandro de la O Puerta, Keeron Stone, Simon Fryer
PURPOSE: To examine differences in oxygenation kinetics in the nondominant and dominant flexor digitorum profundus (FDP) of rock climbers. METHODS: Participants were 28 sport climbers with a range of on-site abilities (6a+ to 8a French Sport). Using near-infrared spectroscopy, oxygenation kinetics of the FDP was assessed by calculating the time to half recovery (t1/2 recovery) of the tissue-saturation index (TSI) after 3-5 min of ischemia. RESULTS: A 2-way mixed-model ANOVA found a nonsignificant interaction (P = ...
January 2017: International Journal of Sports Physiology and Performance
Tobias Bornhütter, Judith Pohl, Christian Fischer, Irena Saltsman, Atif Mahammed, Zeev Gross, Beate Röder
Recent studies show the feasibility of photodynamic inactivation of green algae as a vital step towards an effective photodynamic suppression of biofilms by using functionalized surfaces. The investigation of the intrinsic mechanisms of photodynamic inactivation in green algae represents the next step in order to determine optimization parameters. The observation of singlet oxygen luminescence kinetics proved to be a very effective approach towards understanding mechanisms on a cellular level. In this study, the first two-dimensional measurement of singlet oxygen kinetics in phototrophic microorganisms on surfaces during photodynamic inactivation is presented...
April 13, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Michael Pfitzner, Jan C Schlothauer, Estelle Bastien, Steffen Hackbarth, Lina Bezdetnaya, Henri-Pierre Lassalle, Beate Röder
BACKGROUND: Singlet oxygen observation is considered a valuable tool to assess and optimize PDT treatment. In complex systems, such as tumors in vivo, only the direct, time-resolved singlet oxygen luminescence detection can give reliable information about generation and interaction of singlet oxygen. Up to now, evaluation of kinetics was not possible due to insufficient signal-to-noise ratio. Here we present high signal-to-noise ratio singlet oxygen luminescence kinetics obtained in mouse tumor model under PDT relevant conditions...
June 2016: Photodiagnosis and Photodynamic Therapy
Martin Matejovic, Can Ince, Lakhmir S Chawla, Roland Blantz, Bruce A Molitoris, Mitchell H Rosner, Mark D Okusa, John A Kellum, Claudio Ronco
Novel therapeutic interventions are required to prevent or treat AKI. To expedite progress in this regard, a consensus conference held by the Acute Dialysis Quality Initiative was convened in April of 2014 to develop recommendations for research priorities and future directions. Here, we highlight the concepts related to renal hemodynamics in AKI that are likely to reveal new treatment targets on investigation. Overall, we must better understand the interactions between systemic, total renal, and glomerular hemodynamics, including the role of tubuloglomerular feedback...
January 2016: Journal of the American Society of Nephrology: JASN
Ryan A Boyd, Anthony Gandin, Asaph B Cousins
The photosynthetic assimilation of CO2 in C4 plants is potentially limited by the enzymatic rates of Rubisco, phosphoenolpyruvate carboxylase (PEPc), and carbonic anhydrase (CA). Therefore, the activity and kinetic properties of these enzymes are needed to accurately parameterize C4 biochemical models of leaf CO2 exchange in response to changes in CO2 availability and temperature. There are currently no published temperature responses of both Rubisco carboxylation and oxygenation kinetics from a C4 plant, nor are there known measurements of the temperature dependency of the PEPc Michaelis-Menten constant for its substrate HCO3 (-), and there is little information on the temperature response of plant CA activity...
November 2015: Plant Physiology
Anthony J Barron, Niti M Dhutia, Sven Gläser, Beate Koch, Ralf Ewert, Anne Obst, Marcus Dörr, Henry Völzke, Darrel P Francis, Roland Wensel
BACKGROUND: Cardiopulmonary exercise testing allows for assessment of cardiac and respiratory limitation, but is often affected by patient effort. Indices of oxygen kinetics, including the oxygen uptake efficiency slope (OUES), oxygen uptake-work-rate slope (VO2-WR slope) and the heart rate-oxygen uptake slope (HR-VO2 slope) are relatively effort independent but may be affected by patient characteristics. The objective of this study is to identify the impact of factors, such as age, gender, body size, respiratory function, smoking and beta-blockade on these parameters, as well as generate predictive equations...
June 2015: IJC Metabolic & Endocrine
Marc Fortin, Pierre-Yves Turgeon, Éric Nadreau, Pierre Grégoire, Louis-Gabriel Maltais, Mario Sénéchal, Steeve Provencher, François Maltais
BACKGROUND: Peak oxygen uptake (V˙O2peak) is a well-established prognostic marker in chronic heart failure (CHF). Cardiopulmonary exercise testing (CPET) provides physiological parameters other than V˙O2peak that might have prognostic value. We aimed at determining whether exercise recovery data kinetics have prognostic implications over V˙O2peak and Heart Failure Survival Score. METHODS: Exercise data from 200 consecutive CHF patients evaluated for possible heart transplantation and received CPET at our institution between 2004 and 2011 were analyzed...
October 2015: Canadian Journal of Cardiology
Satyam Sarma, Benjamin D Levine
Patients with heart failure with preserved ejection fraction (HFpEF) have similar degrees of exercise intolerance and dyspnea as patients with heart failure with reduced EF (HFrEF). The underlying pathophysiology leading to impaired exertional ability in the HFpEF syndrome is not completely understood, and a growing body of evidence suggests "peripheral," i.e., noncardiac, factors may play an important role. Changes in skeletal muscle function (decreased muscle mass, capillary density, mitochondrial volume, and phosphorylative capacity) are common findings in HFrEF...
September 15, 2015: Journal of Applied Physiology
Michael J Stark, Nicolette A Hodyl, Chad C Andersen
BACKGROUND: The underlying neuro-protective mechanisms of antenatal magnesium sulfate (MgSO(4)) in infants born preterm remain poorly understood. Early neonatal brain injury may be preceded by low cerebral blood flow (CBF) and elevated cerebral fractional tissue oxygen extraction (cFTOE). This study investigated the effect of antenatal MgSO(4) on cerebral oxygen delivery, consumption, and cFTOE in preterm infants. METHODS: CBF and tissue oxygenation index were measured, and oxygen delivery, consumption, and cFTOE calculated within 24 h of birth and at 48 and 72 h of life in 36 infants ≤ 30 wk gestation exposed to MgSO(4) and 29 unexposed infants...
September 2015: Pediatric Research
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