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Oxygen uptake kinetics

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
Michael I Jacobs, Bo Xu, Oleg Kostko, Nadja Heine, Musahid Ahmed, Kevin R Wilson
The heterogeneous reaction of ozone (O3) with 200 nm squalene nanoparticles is studied using near edge X-ray absorption fine structure (NEXAFS), ultraviolet (UPS) and X-ray photoelectron spectroscopy (XPS). Photoelectrons are detected from free nanoparticle beams using a velocity map imaging (VMI) spectrometer capable of detecting photoelectrons with up to 40 eV of kinetic energy. Heterogeneous kinetics are quantified using changes in the UPS, XPS and NEXAFS spectrum, yielding uptake coefficients for the decay of the double bonds in squalene of (3...
October 17, 2016: Journal of Physical Chemistry. A
Rogério Santos Cde Oliveira Cruz, Tiago Turnes, Rafael Alves de Aguiar, Fabrizio Caputo
The off-transient pulmonary oxygen uptake (V̇O2) response to a single bout of intense, exhaustive exercise has been characterized over the years by a second-order exponential model. In this paper, we report the superiority of a third-order exponential decay in describing the V̇O2 off-kinetics after a maximal cycling exercise lasting 60-s. Our findings are in accordance with a biphasic pattern of phosphocreatine resynthesis when muscle pH is affected.
October 12, 2016: Respiratory Physiology & Neurobiology
Dalin Shi, Dongmei Lv, Wanxin Liu, Rong Shen, Dongmei Li, Haizheng Hong
The brominated flame retardants hexabromocyclododecanes (HBCDs) are ubiquitous environmental contaminants, widely distributed in aquatic systems including the marine environment and marine organisms. HBCDs are toxic to the development of both freshwater and marine fish. However, the impacts of HBCDs on marine invertebrates are not well known. In this study, the marine copepod, Tigriopus japonicus, was used to assess the bioaccumulation and developmental toxicity of technical HBCD (tHBCD) through water-borne exposure...
October 5, 2016: Chemosphere
Richard B Thompson, Joseph J Pagano, Kory W Mathewson, Ian Paterson, Jason R Dyck, Dalane W Kitzman, Mark J Haykowsky
The goals of the current study were to compare leg blood flow, oxygen extraction and oxygen uptake (VO2) after constant load sub-maximal unilateral knee extension (ULKE) exercise in patients with heart failure with reduced ejection fraction (HFrEF) compared to those with preserved ejection fraction (HFpEF). Previously, it has been shown that prolonged whole body VO2 recovery kinetics are directly related to disease severity and all-cause mortality in HFrEF patients. To date, no study has simultaneously measured muscle-specific blood flow and oxygen extraction post exercise recovery kinetics in HFrEF or HFpEF patients; therefore it is unknown if muscle VO2 recovery kinetics, and more specifically, the recovery kinetics of blood flow and oxygen extraction at the level of the muscle, differ between HF phenotypes...
2016: PloS One
Joshua P Nederveen, Daniel A Keir, Lorenzo K Love, Harry B Rossiter, John M Kowalchuk
We examined the effect of heavy-intensity 'priming' exercise on the rate of adjustment of pulmonary O2 uptake (τV˙O2p) initiated from elevated intensities. Fourteen men (separated into two groups: τV˙O2p≤25s [Fast] or τV˙O2p>25s [Slow]) completed step-transitions from 20W to 45% lactate threshold (LT; lower-step, LS) and 45% to 90%LT (upper-step, US) performed (i) without; and (ii) with US preceded by heavy-intensity exercise (HUS). Breath-by-breath V˙O2p and near-infrared spectroscopy-derived muscle deoxygenation ([HHb+Mb]) were measured...
September 28, 2016: Respiratory Physiology & Neurobiology
Dani H Leviss, Daryl A Van Ry, Ryan Z Hinrichs
Multiphase ozonolysis of aqueous organics presents a potential pathway for the formation of aqueous secondary organic aerosol (aqSOA). We investigated the multiphase ozonolysis of α-terpineol, an oxygenated derivative of limonene, and found that the reaction products and kinetics differ from the gas-phase ozonolysis of α-terpineol. One- and two-dimensional NMR spectroscopies along with GC-MS identified the aqueous ozonolysis reaction products as trans- and cis-lactols [4-(5-hydroxy-2,2-dimethyltetrahydrofuran-3-yl)butan-2-one] and a lactone [4-hydroxy-4-methyl-3-(3-oxobutyl)-valeric acid gamma-lactone], which accounted for 46%, 27%, and 20% of the observed products, respectively...
October 13, 2016: Environmental Science & Technology
Katarzyna Paździor, Anna Klepacz-Smółka, Julita Wrębiak, Ewa Liwarska-Bizukojć, Stanisław Ledakowicz
Following new trends we applied oxygen uptake rate (OUR) tests as well as long-term tests (in two batch bioreactors systems) in order to assess the biodegradability of textile wastewater. Effluents coming from a dyeing factory were divided into two streams which differed in inorganic and organic contaminants loads. Usefulness of the stream division was proved. Biodegradation of the low-loaded stream led to over 97% reduction of biochemical oxygen demand (BOD5) together with 80% reduction of chemical oxygen demand (COD) and total organic carbon (TOC)...
September 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Thomas Wanek, Katharina Kreis, Petra Križková, Anna Schweifer, Christoph Denk, Johann Stanek, Severin Mairinger, Thomas Filip, Michael Sauberer, Patricia Edelhofer, Alexander Traxl, Viktoria E Muchitsch, Kurt Mereiter, Friedrich Hammerschmidt, Carol E Cass, Vijaya L Damaraju, Oliver Langer, Claudia Kuntner
Positron emission tomography (PET) using fluorine-18 ((18)F)-labeled 2-nitroimidazole radiotracers has proven useful for assessment of tumor oxygenation. However, the passive diffusion-driven cellular uptake of currently available radiotracers results in slow kinetics and low tumor-to-background ratios. With the aim to develop a compound that is actively transported into cells, 1-(6'-deoxy-6'-[(18)F]fluoro-β-d-allofuranosyl)-2-nitroimidazole (β-[(18)F]1), a putative nucleoside transporter substrate, was synthetized by nucleophilic [(18)F]fluoride substitution of an acetyl protected labeling precursor with a tosylate leaving group (β-6) in a final radiochemical yield of 12±8% (n=10, based on [(18)F]fluoride starting activity) in a total synthesis time of 60min with a specific activity at end of synthesis of 218±58GBq/μmol (n=10)...
November 1, 2016: Bioorganic & Medicinal Chemistry
Poonam Phalak, Jin Chen, Ross P Carlson, Michael A Henson
BACKGROUND: Chronic wounds are often colonized by consortia comprised of different bacterial species growing as biofilms on a complex mixture of wound exudate. Bacteria growing in biofilms exhibit phenotypes distinct from planktonic growth, often rendering the application of antibacterial compounds ineffective. Computational modeling represents a complementary tool to experimentation for generating fundamental knowledge and developing more effective treatment strategies for chronic wound biofilm consortia...
2016: BMC Systems Biology
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
Antonio Paciello, Giuseppe Amalfitano, Alessandro Garziano, Francesco Urciuolo, Paolo A Netti
In this study, a novel micrometric biomaterial acting as a cyclic oxygen releasing system is designed. Human hemoglobin (Hb) is conjugated to the surface of gelatin microspheres (GM) to produce gelatin hemoglobin oxygen depot (G-HbOD). G-HbOD is obtained by means of two different conjugation strategies. The degree of conjugation of GM surfaces in terms of free amino groups by using HPLC is first evaluated. By following the strategy A (G-HbOD_A), Hb is conjugated to GM by means of the formation of a polyurethane linker...
September 5, 2016: Advanced Healthcare Materials
Norio Hotta, Hisayoshi Ogata, Takaharu Kondo, Koji Ishida, Michael R Kushnick
No abstract text is available yet for this article.
May 2016: Medicine and Science in Sports and Exercise
Chad C Wiggins, Shane A Bielko, Allison J Campbell, Timothy D Mickleborough, Robert F Chapman
No abstract text is available yet for this article.
May 2016: Medicine and Science in Sports and Exercise
Eskedar Ayele Angamo, Joerg Roesner, Agustin Liotta, Richard Kovacs, Uwe Heinemann
Astrocyte derived lactate supports pathologically enhanced neuronal metabolism but its role under physiological conditions is still a matter of debate. Here, we determined the contribution of astrocytic neuronal lactate shuttle to maintenance of ion homeostasis and energy metabolism. We tested for the effects of α-cyano-4-hydroxycinnamic acid (4-CIN), which could interfere with energy metabolism by blocking monocarboxylate-transporter 2 (MCT2) mediated neuronal lactate uptake, on evoked potentials, stimulus induced changes in K(+), Na(+), Ca(2+) and oxygen concentrations as well as on changes in flavin adenine dinucleotide (FAD) autofluorescence in the hippocampal area CA3...
August 24, 2016: Journal of Neurophysiology
Linqiong Wang, Yi Li, Lihua Niu, Wenlong Zhang, Jie Li, Nan Yang
Understanding the interaction between microorganisms and fluid dynamics is important for aquatic ecosystems, though only sporadic attention has been focused on this topic in the past. In this study, particular attention was paid to the phenol-degrading bacterial strains Microbacterium oxydans LY1 and Alcaligenes faecalis LY2 subjected to controlled fluid flow under laboratory conditions. These two strains were found to be able to degrade phenols over a concentration range from 50 to 500 mg/L under different turbulence conditions ranging from 0 to 250 rpm...
August 25, 2016: Environmental Science and Pollution Research International
Song Zhu, Bin Zhu, Aiguo Huang, Yang Hu, Gaoxue Wang, Fei Ling
Using Saccharomyces cerevisiae as an experimental model, the potential toxicological effects of oxidized multi-walled carbon nanotubes (MWCNTs) were investigated following exposure to 0-600mg/L for 24h. Results indicated that MWCNTs (>100mg/L) had adverse effects on the cell proliferation. MWCNTs were clearly visible in lysosome, vacuole, endosome, mitochondria, multivesicular body and localization in the perinuclear region. The uptake kinetics data demonstrated that the maximum MWCNTs content (209.61mg/g) was reached at 3h, and a steady state was reached after 18h...
November 15, 2016: Journal of Hazardous Materials
Behrooz Soltani, Nasser Ghaemi, Majid Sadeghizadeh, Farhood Najafi
Exposure to ionizing radiation (IR) could be detrimental to health. Oxidative stress, DNA damage, and inflammation are implicated in radiation damage. Curcumin, a natural polyphenol, has remarkable antioxidant, anti-inflammation and anticarcinogenic properties and is reported to protect cells and organisms against gamma-rays. We have recently enhanced solubility of curcumin via a novel dendrosomal nanoformulation (DNC). The objective of this study was to assess the potential efficacy of this nanoformulation in protecting human peripheral blood mononuclear cells (PBMC) against gamma-radiation...
September 25, 2016: Chemico-biological Interactions
Simone Porcelli, Mauro Marzorati, Lucia Morandi, Bruno Grassi
Aerobic training can be effective in patients with mitochondrial myopathies (MM) and McArdle's disease (McA). The aim of the study was to use noninvasive functional evaluation methods, specifically aimed at skeletal muscle oxidative metabolism, to evaluate the effects of an aerobic exercise training (cycle ergometer, 12 wk, 4 days/wk, ∼65-70% of maximal heart rate) in 6 MM and 7 McA. Oxygen uptake and skeletal muscle vastus lateralis fractional O2 extraction by near-infrared spectroscopy were assessed during incremental and low-intensity constant work rate (CWR) exercises before (BEFORE) and at the end (AFTER) of training...
September 1, 2016: Journal of Applied Physiology
Ruud F Spee, Victor M Niemeijer, Pieter F Wijn, Pieter A Doevendans, Hareld M Kemps
BACKGROUND: High-intensity interval training (HIT) improves exercise capacity in patients with chronic heart failure (CHF). Moreover, HIT was associated with improved resting cardiac function. However, the extent to which these improvements actually contribute to training-induced changes in exercise capacity remains to be elucidated. Therefore, we evaluated the effects of HIT on exercising central haemodynamics and skeletal muscle oxygenation. METHODS: Twenty-six CHF patients were randomised to a 12-week 4 × 4 minute HIT program at 85-95% of peak VO2 or usual care...
July 20, 2016: European Journal of Preventive Cardiology
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