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Oxygen uptake kinetics

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https://www.readbyqxmd.com/read/28215595/gas-exchange-kinetics-following-concentric-eccentric-isokinetic-arm-and-leg-exercise
#1
U Drescher, S Mookerjee, A Steegmanns, A Knicker, U Hoffmann
PURPOSE: To evaluate the effects of exercise velocity (60, 150, 240 deg·s(-1)) and muscle mass (arm vs leg) on changes in gas exchange and arterio-venous oxygen content difference (avDO2) following high-intensity concentric-eccentric isokinetic exercise. METHODS: Fourteen subjects (26.9±3.1years) performed a 3×20-repetition isokinetic exercise protocol. Recovery beat-to-beat cardiac output (CO) and breath-by-breath gas exchange were recorded to determine post-exercise half-time (t1/2) for oxygen uptake (V'O2pulm), carbon dioxide output (V'CO2pulm), and ventilation (V'E)...
February 16, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28202306/nitrite-oxidation-kinetics-of-two-nitrospira-strains-the-quest-for-competition-and-ecological-niche-differentiation
#2
Norisuke Ushiki, Masaru Jinno, Hirotsugu Fujitani, Toshikazu Suenaga, Akihiko Terada, Satoshi Tsuneda
Nitrite oxidation is an aerobic process of the nitrogen cycle in natural ecosystems, and is performed by nitrite-oxidizing bacteria (NOB). Also, nitrite oxidation is a rate-limiting step of nitrogen removal in wastewater treatment plants (WWTPs). Although Nitrospira is known as dominant NOB in WWTPs, information on their physiological properties and kinetic parameters is limited. Here, we report the kinetic parameters and inhibition of nitrite oxidation by free ammonia in pure cultures of Nitrospira sp. strain ND1 and Nitrospira japonica strain NJ1, which were previously isolated from activated sludge in a WWTP...
February 12, 2017: Journal of Bioscience and Bioengineering
https://www.readbyqxmd.com/read/28201825/heart-rate-and-oxygen-uptake-kinetics-in-type-2-diabetes-patients-a-pilot-study-on-the-influence-of-cardiovascular-medication-on-regulatory-processes
#3
Jessica Koschate, Uwe Drescher, Klaus Baum, Christian Brinkmann, Thorsten Schiffer, Joachim Latsch, Klara Brixius, Uwe Hoffmann
The aim of this pilot study was to investigate whether there are differences in heart rate and oxygen uptake kinetics in type 2 diabetes patients, considering their cardiovascular medication. It was hypothesized that cardiovascular medication would affect heart rate and oxygen uptake kinetics and that this could be detected using a standardized exercise test. 18 subjects were tested for maximal oxygen uptake. Kinetics were measured in a single test session with standardized, randomized moderate-intensity work rate changes...
February 15, 2017: Experimental and Clinical Endocrinology & Diabetes
https://www.readbyqxmd.com/read/28174679/engineering-remotely-triggered-liposomes-to-target-triple-negative-breast-cancer
#4
Alexandra Sneider, Rahul Jadia, Brandon Piel, Derek VanDyke, Christopher Tsiros, Prakash Rai
Triple Negative Breast Cancer (TNBC) continues to present a challenge in the clinic, as there is still no approved targeted therapy. TNBC is the worst sub-type of breast cancer in terms of prognosis and exhibits a deficiency in estrogen, progesterone, and human epidermal growth factor 2 (HER2) receptors. One possible option for the treatment of TNBC is chemotherapy. The issue with many chemotherapy drugs is that their effectiveness is diminished due to poor water solubility, and the method of administration directly or with a co-solvent intravenously can lead to an increase in toxicity...
2017: Oncomedicine
https://www.readbyqxmd.com/read/28153947/corp-measurement-of-the-maximum-oxygen-uptake-vo2max-vo2peak-is-no-longer-acceptable
#5
David C Poole, Andrew M Jones
The maximum rate of VO2 uptake (i.e., VO2max), as measured during large muscle mass exercise such as cycling or running, is widely considered to be the gold standard measurement of integrated cardiopulmonary-muscle oxidative function. The development of rapid-response gas analyzers, enabling measurement of breath-by-breath pulmonary gas exchange, has led to replacement of the discontinuous progressive maximal exercise test (that produced an unambiguous VO2-work rate plateau definitive for VO2max) with the rapidly-incremented or ramp testing protocol...
February 2, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28151429/the-influence-of-adipose-tissue-on-spatially-resolved-near-infrared-spectroscopy-derived-skeletal-muscle-oxygenation-the-extent-of-the-problem
#6
Victor M Niemeijer, Jasper P Jansen, Thomas van Dijk, Ruud F Spee, Eduard J Meijer, Hareld M C Kemps, Pieter F F Wijn
OBJECTIVE: Near-infrared spectroscopy (NIRS) measurements of tissue oxygen saturation (StO2) are useful for the assessment of skeletal muscle perfusion and function during exercise, however, they are influenced by overlying skin and adipose tissue. This study explored the extent and nature of the influence of adipose tissue thickness (ATT) on StO2. APPROACH: NIR spatially resolved spectroscopy (SRS) derived oxygenation was measured on vastus lateralis in 56 patients with chronic heart failure (CHF) and 20 healthy control (HC) subjects during rest and moderate intensity exercise with simultaneous assessment of oxygen uptake kinetics (τ [Formula: see text])...
February 2, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28149379/the-oxygen-uptake-slow-component-at-submaximal-intensities-in-breaststroke-swimming
#7
Diogo R Oliveira, Lio F Gonçalves, António M Reis, Ricardo J Fernandes, Nuno D Garrido, Victor M Reis
The present work proposed to study the oxygen uptake slow component (VO2 SC) of breaststroke swimmers at four different intensities of submaximal exercise, via mathematical modeling of a multi-exponential function. The slow component (SC) was also assessed with two different fixed interval methods and the three methods were compared. Twelve male swimmers performed a test comprising four submaximal 300 m bouts at different intensities where all expired gases were collected breath by breath. Multi-exponential modeling showed values above 450 ml·min(-1) of the SC in the two last bouts of exercise (those with intensities above the lactate threshold)...
June 1, 2016: Journal of Human Kinetics
https://www.readbyqxmd.com/read/28143453/pulmonary-oxygen-uptake-and-muscle-deoxygenation-kinetics-during-heavy-intensity-cycling-exercise-in-patients-with-emphysema-and-idiopathic-pulmonary-fibrosis
#8
Melitta A McNarry, Nicholas K Harrison, Tom Withers, Narendra Chinnappa, Michael J Lewis
BACKGROUND: Little is known about the mechanistic basis for the exercise intolerance characteristic of patients with respiratory disease; a lack of clearly defined, distinct patient groups limits interpretation of many studies. The purpose of this pilot study was to investigate the pulmonary oxygen uptake ([Formula: see text] O2) response, and its potential determinants, in patients with emphysema and idiopathic pulmonary fibrosis (IPF). METHODS: Following a ramp incremental test for the determination of peak [Formula: see text] O2 and the gas exchange threshold, six emphysema (66 ± 7 years; FEV1, 36 ± 16%), five IPF (65 ± 12 years; FEV1, 82 ± 11%) and ten healthy control participants (63 ± 6 years) completed three repeat, heavy-intensity exercise transitions on a cycle ergometer...
January 31, 2017: BMC Pulmonary Medicine
https://www.readbyqxmd.com/read/28134660/muscle-strength-but-not-muscle-oxidative-capacity-varies-between-the-morning-and-the-afternoon-in-patients-with-multiple-sclerosis-a-pilot-study
#9
Inez Wens, Dominique Hansen
Despite frequent muscle strength or muscle oxidative capacity (based on exercise-onset oxygen uptake [VO2] kinetics) assessments in patients with multiple sclerosis, the impact of time of day on these parameters is often not taken into account. Based on observations in healthy subjects, it remains to be studied whether muscle strength, and/or exercise-onset VO2 kinetics, varies between the morning and the afternoon in patients with multiple sclerosis. In this prospective observational pilot study, walking capacity, exercise-onset VO2 kinetics, isometric knee extension/flexion strength (dynamometry), and self-reported fatigue were measured in 11 patients with multiple sclerosis (age, 51...
January 27, 2017: American Journal of Physical Medicine & Rehabilitation
https://www.readbyqxmd.com/read/28125917/a-study-of-water-uptake-by-selected-superdisintegrants-from-the-sub-molecular-to-the-particulate-level
#10
P Barmpalexis, P Syllignaki, K Kachrimanis
Water diffusion through the matrix of three superdisintegrants, namely sodium starch glycolate (SSG), croscarmellose sodium (cCMC-Na) and crospovidone (cPVP), was studied at the sub-molecular level using Attenuated Total Reflectance (ATR)-FTIR spectroscopy and molecular dynamics simulations, and the results were correlated to water uptake studies conducted at the particulate level using Parallel Exponential Kinetics (PEK) modeling in dynamic moisture sorption studies and optical microscopy. ATR-FTIR studies indicated that water diffuses inside cPVP by a single fast acting process, while in SSG and cCMC-Na, a slow and a fast process acting simultaneously, were identified...
January 26, 2017: Pharmaceutical Development and Technology
https://www.readbyqxmd.com/read/28122720/similar-pattern-of-change-in-v%C3%AC-o2-kinetics-vascular-function-and-tissue-oxygen-provision-following-an-endurance-training-stimulus-in-older-and-young-adults
#11
Kaitlin M McLay, Juan M Murias, Donald H Paterson
PURPOSE: To examine the time-course of changes in the oxygen uptake (V̇O2) kinetics response subsequent to short-term exercise training (i.e., 24h, 48h, 72h, and 120h post-training) and examine the relationship with the time-course of changes in microvascular (deoxygenated hemoglobin concentration ([HHb])/V̇O2 ratio) and macrovascular (flow-mediated dilation (FMD)) O2 delivery to the active tissues/limbs. METHODS: Seven healthy older (OA: 74±6yr) and young men (YA: 25±3yr) completed three endurance cycling exercise training sessions at 70% V̇O2max Moderate-intensity exercise on-transient V̇O2 (measured breath-by-breath) and [HHb] (measured by near-infrared spectroscopy) were modeled with a mono-exponential and normalized (0-100% of response) and the [HHb]/V̇O2 ratio was calculated...
January 25, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/28108649/intracellular-oxygen-tension-limits-muscle-contraction-induced-change-in-muscle-oxygen-consumption-under-hypoxic-conditions-during-hb-free-perfusion
#12
Hisashi Takakura, Minoru Ojino, Thomas Jue, Tatsuya Yamada, Yasuro Furuichi, Takeshi Hashimoto, Satoshi Iwase, Kazumi Masuda
Under acute hypoxic conditions, the muscle oxygen uptake (mV˙O2) during exercise is reduced by the restriction in oxygen-supplied volume to the mitochondria within the peripheral tissue. This suggests the existence of a factor restricting the mV˙O2 under hypoxic conditions at the peripheral tissue level. Therefore, this study set out to test the hypothesis that the restriction in mV˙O2 is regulated by the net decrease in intracellular oxygen tension equilibrated with myoglobin oxygen saturation (∆PmbO2) during muscle contraction under hypoxic conditions...
January 2017: Physiological Reports
https://www.readbyqxmd.com/read/28088096/mycelium-transformation-of-streptomyces-toxytricini-into-pellet-role-of-culture-conditions-and-kinetics
#13
Punit Kumar, Kashyap Kumar Dubey
The present study envisages the role of different carbon sources, nitrogen sources, metals, pH, inoculum volume and agitation rate in pellet formation of S. toxytricini at shake-flask level. It was found that galactose, ammonium sulphate, sodium nitrate, Cu(2+), Zn(2+), higher inoculum volume (5% v/v) and agitation rate at 300rpm caused significant reduction in pellet size (up to the range of 30μm-0.5mm) but biomass formations was also reduced subsequently. Interestingly diffused type of morphology was obtained in Fe(2+) supplemented medium with reduced biomass (1...
March 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28057820/blood-flow-regulation-and-oxygen-uptake-during-high-intensity-forearm-exercise
#14
Stian Kwak Nyberg, Ole Kristian Berg, Jan Helgerud, Eivind Wang
The vascular strain is very high during heavy handgrip exercise, but the intensity and kinetics to reach peak blood flow, and peak oxygen uptake, are uncertain. We included 9 young (25±2yr) healthy males to evaluate blood flow and oxygen uptake responses during continuous dynamic handgrip exercise with increasing intensity. Blood flow was measured using Doppler-ultrasound and venous blood was drawn from a deep forearm vein to determine arteriovenous oxygen difference (a-vO2diff) during 6-minutes bouts of 60, 80 and 100% of maximal work rate (WRmax), respectively...
January 5, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28018674/early-phase-recovery-of-cardiorespiratory-measurements-after-maximal-cardiopulmonary-exercise-testing-in-patients-with-chronic-obstructive-pulmonary-disease
#15
Marie Bellefleur, David Debeaumont, Alain Boutry, Marie Netchitailo, Antoine Cuvelier, Jean-François Muir, Catherine Tardif, Jérémy Coquart
Background. This study investigated respiratory gas exchanges and heart rate (HR) kinetics during early-phase recovery after a maximal cardiopulmonary exercise test (CPET) in patients with chronic obstructive pulmonary disease (COPD) grouped according to airflow limitation. Methods. Thirty control individuals (control group: CG) and 81 COPD patients (45 with "mild" or "moderate" airflow limitation, COPDI-II, versus 36 with "severe" or "very severe" COPD, COPDIII-IV) performed a maximal CPET. The first 3 min of recovery kinetics was investigated for oxygen uptake ([Formula: see text]O2), minute ventilation ([Formula: see text]), respiratory equivalence, and HR...
2016: Pulmonary Medicine
https://www.readbyqxmd.com/read/27994556/endurance-performance-during-severe-intensity-intermittent-cycling-effect-of-exercise-duration-and-recovery-type
#16
Luis F Barbosa, Benedito S Denadai, Camila C Greco
Slow component of oxygen uptake (VO2SC) kinetics and maximal oxygen uptake (VO2max) attainment seem to influence endurance performance during constant-work rate exercise (CWR) performed within the severe intensity domain. In this study, it was hypothesized that delaying the attainment of VO2max by reducing the rates at which VO2 increases with time (VO2SC kinetics) would improve the endurance performance during severe-intensity intermittent exercise performed with different work:recovery duration and recovery type in active individuals...
2016: Frontiers in Physiology
https://www.readbyqxmd.com/read/27993287/addition-of-vitamin-b12-to-exercise-training-improves-cycle-ergometer-endurance-in-advanced-copd-patients-a-randomized-and-controlled-study
#17
Fernanda Viana Paulin, Alessandro Moura Zagatto, Gaspar R Chiappa, Paulo de Tarso Müller
Vitamin B12 is essential in the homocysteine, mitochondrial, muscle and hematopoietic metabolisms, and its effects on exercise tolerance and kinetics adjustments of oxygen consumption (V'O2p) in rest-to-exercise transition in COPD patients are unknown. This randomized, double-blind, controlled study aimed to verify a possible interaction between vitamin B12 supplementation and these outcomes. After recruiting 69 patients, 35 subjects with moderate-to-severe COPD were eligible and 32 patients concluded the study, divided into four groups (n = 8 for each group): 1...
January 2017: Respiratory Medicine
https://www.readbyqxmd.com/read/27979503/effect-of-physical-training-on-the-recovery-of-acute-exercise-among-patients-with-cardiovascular-disease
#18
Marianna García-Saldivia, Hermes Ilarraza-Lomelí, Jonathan Myers, Jorge Lara, Leopoldo Bueno
INTRODUCTION: Physical training programs (PTP) have shown several beneficial effects for patients with cardiovascular disease (CVD), particularly by increasing survival and quality of life. Physiological response during the effort and recovery phases of an exercise testing, is one of the strongest prognostic markers among patients with CVD. A reasonable mechanism that explains those training effects on survival is through the adaptations seen on heart rate recovery (HRR) and oxygen uptake kinetics at the post-exertional phase (RVO2)...
December 12, 2016: Archivos de Cardiología de México
https://www.readbyqxmd.com/read/27951646/phe28-b10-induces-channel-forming-cytotoxic-amyloid-fibrillation-in-human-neuroglobin-the-brain-specific-hemoglobin
#19
Sheetal Uppal, Amit Kumar Singh, Richa Arya, Debanjan Tewari, Neha Jaiswal, Abhijeet Kapoor, Amal Kanti Bera, Alo Nag, Suman Kundu
Since its discovery, neuroglobin (Ngb), a neuron-specific oxygen binding hemoglobin, distinct from the classical myoglobin and blood hemoglobin, has attracted attention as an endogenous neuroprotectant. Recent reports suggest that Ngb protects neurons from brain stroke, ischemic stress-induced degeneration, and other brain disorders. Proteins with a specific role in neuroprotection are often associated with neurodegeneration, as well, depending on the cellular environment or specific cellular triggers that tilt the balance one way or the other...
December 13, 2016: Biochemistry
https://www.readbyqxmd.com/read/27920767/ecophysiology-and-comparative-genomics-of-nitrosomonas-mobilis-ms1-isolated-from-autotrophic-nitrifying-granules-of-wastewater-treatment-bioreactor
#20
Soe Myat Thandar, Norisuke Ushiki, Hirotsugu Fujitani, Yuji Sekiguchi, Satoshi Tsuneda
Ammonia-oxidizing bacteria (AOB), which oxidize ammonia to nitrite in the first step of nitrification, play an important role in biological wastewater treatment systems. Nitrosomonas mobilis is an important and dominant AOB in various wastewater treatment systems. However, the detailed physiological and genomic properties of N. mobilis have not been thoroughly investigated because of limited success isolating pure cultures. This study investigated the key physiological characteristics of N. mobilis Ms1, which was previously isolated into pure culture from the nitrifying granules of wastewater treatment bioreactor...
2016: Frontiers in Microbiology
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