WorldWideScience

Sample records for submaximal oxygen consumption

  1. Myocardial oxygen consumption at rest and during submaximal ...

    African Journals Online (AJOL)

    Overweight and obesity are major risk factors for cardiovascular diseases. The objective of this study was to determine the effect of increased adiposity on myocardial oxygen consumption at rest and during submaximal exercise in young adults. The study consisted of 85 young adults (18-22years) grouped into 3 based on ...

  2. Developmental Effects Determine Submaximal Arterial Oxygen Saturation in Peruvian Quechua.

    Science.gov (United States)

    Kiyamu, Melisa; León-Velarde, Fabiola; Rivera-Chira, María; Elías, Gianpietro; Brutsaert, Tom D

    2015-06-01

    Kiyamu, Melisa, Fabiola León-Velarde, María Rivera-Chira, Gianpietro Elías, and Tom D. Brutsaert. Developmental effects determine submaximal arterial oxygen saturation in Peruvian Quechua. High Alt Med Biol 16, 138-146, 2015.--Andean high altitude natives show higher arterial oxygen saturation (Sao(2)) during exercise in hypoxia, compared to acclimatized sojourners. In order to evaluate the effects of life-long exposure to high altitude on Sao(2), we studied two groups of well-matched, self-identified Peruvian Quechua natives who differed in their developmental exposure to hypoxia before and after a 2-month training period. Male and female volunteers (18-35 years) were recruited in Lima, Peru (150 m). The two groups were: a) Individuals who were born and raised at sea-level (BSL, n=34) and b) Individuals who were born and raised at high altitude (BHA, n=32), but who migrated to sea-level as adults (>16 years old). Exercise testing was conducted using a submaximal exercise protocol in normobaric hypoxia in Lima (BP=750 mmHg, Fio(2)=0.12), in order to measure Sao(2) (%), ventilation (VE L/min) and oxygen consumption (Vo(2), L/min). Repeated-measures ANOVA, controlling for VE/VO(2) (L/min) and sex during the submaximal protocol showed that BHA maintained higher Sao(2) (%) compared to BSL at all workloads before (p=0.005) and after training (p=0.017). As expected, both groups showed a decrease in Sao(2) (%) (p<0.001), as workload increased. Resting Sao(2) levels were not found to be different between groups. The results suggest that developmental exposure to altitude contributes to the maintenance of higher Sao(2) levels during submaximal exercise at hypoxia.

  3. Low-protein vegetarian diet does not have a short-term effect on blood acid–base status but raises oxygen consumption during submaximal cycling

    Directory of Open Access Journals (Sweden)

    Hietavala Enni-Maria

    2012-11-01

    Full Text Available Abstract Background Acid–base balance refers to the equilibrium between acids and bases in the human body. Nutrition may affect acid–base balance and further physical performance. With the help of PRAL (potential renal acid load, a low-protein vegetarian diet (LPVD was designed to enhance the production of bases in body. The aim of this study was to investigate if LPVD has an effect on blood acid–base status and performance during submaximal and maximal aerobic cycling. Methods Nine healthy, recreationally active men (age 23.5 ± 3.4 yr participated in the study and were randomly divided into two groups in a cross-over study design. Group 1 followed LPVD for 4 days and group 2 ate normally (ND before performing a cycle ergometer test. The test included three 10-min stages at 40, 60 and 80% of VO2max. The fourth stage was performed at 100% of VO2max until exhaustion. After 10–16 days, the groups started a second 4-day diet, and at the end performed the similar ergometer test. Venous blood samples were collected at the beginning and at the end of both diet periods and after every stage cycled. Results Diet caused no significant difference in venous blood pH, strong ion difference (SID, total concentration of weak acids (Atot, partial pressure of CO2 (pCO2 or HCO3- at rest or during cycling between LPVD and ND. In the LPVD group, at rest SID significantly increased over the diet period (38.6 ± 1.8 vs. 39.8 ± 0.9, p=0.009. Diet had no significant effect on exercise time to exhaustion, but VO2 was significantly higher at 40, 60 and 80% of VO2max after LPVD compared to ND (2.03 ± 0.25 vs. 1.82 ± 0.21 l/min, p=0.035; 2.86 ± 0.36 vs. 2.52 ± 0.33 l/min, p Conclusion There was no difference in venous blood acid–base status between a 4-day LPVD and ND. VO2 was increased during submaximal cycling after LPVD suggesting that the exercise economy was poorer. This had no further effect on maximal aerobic performance. More studies are needed to

  4. Submaximal oxygen uptake kinetics, functional mobility, and physical activity in older adults with heart failure and reduced ejection fraction.

    Science.gov (United States)

    Hummel, Scott L; Herald, John; Alpert, Craig; Gretebeck, Kimberlee A; Champoux, Wendy S; Dengel, Donald R; Vaitkevicius, Peter V; Alexander, Neil B

    2016-07-01

    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. Older adults with HF and reduced ejection fraction (n = 25, age 75 ± 7 years) were compared to 25 healthy age- and gender-matched controls. Assessments included a maximal treadmill test for peak oxygen uptake (VO2peak), oxygen uptake kinetics at onset of and on recovery from a submaximal treadmill test, functional mobility testing [Get Up and Go (GUG), Comfortable Gait Speed (CGS), Unipedal Stance (US)], and self-reported physical activity (PA). Compared to controls, HF had worse performance on GUG, CGS, and US, greater delays in submaximal oxygen uptake kinetics, and lower PA. In controls, VO2peak was more strongly associated with functional mobility and PA than submaximal oxygen uptake kinetics. In HF patients, submaximal oxygen uptake kinetics were similarly associated with GUG and CGS as VO2peak, but weakly associated with PA. Based on their mobility performance, older HF patients with reduced ejection fraction are at risk for adverse functional outcomes. In this population, submaximal oxygen uptake measures may be equivalent to VO2 peak in predicting functional mobility, and in addition to being more feasible, may provide better insight into how aerobic function relates to mobility in older adults with HF.

  5. Submaximal oxygen uptake kinetics, functional mobility, and physical activity in older adults with heart failure and reduced ejection fraction

    OpenAIRE

    Hummel, Scott L; Herald, John; Alpert, Craig; Gretebeck, Kimberlee A; Champoux, Wendy S; Dengel, Donald R; Vaitkevicius, Peter V; Alexander, Neil B

    2016-01-01

    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 cont...

  6. Estimation of maximal oxygen uptake via submaximal exercise testing in sports, clinical, and home settings.

    Science.gov (United States)

    Sartor, Francesco; Vernillo, Gianluca; de Morree, Helma M; Bonomi, Alberto G; La Torre, Antonio; Kubis, Hans-Peter; Veicsteinas, Arsenio

    2013-09-01

    Assessment of the functional capacity of the cardiovascular system is essential in sports medicine. For athletes, the maximal oxygen uptake [Formula: see text] provides valuable information about their aerobic power. In the clinical setting, the (VO(2max)) provides important diagnostic and prognostic information in several clinical populations, such as patients with coronary artery disease or heart failure. Likewise, VO(2max) assessment can be very important to evaluate fitness in asymptomatic adults. Although direct determination of [VO(2max) is the most accurate method, it requires a maximal level of exertion, which brings a higher risk of adverse events in individuals with an intermediate to high risk of cardiovascular problems. Estimation of VO(2max) during submaximal exercise testing can offer a precious alternative. Over the past decades, many protocols have been developed for this purpose. The present review gives an overview of these submaximal protocols and aims to facilitate appropriate test selection in sports, clinical, and home settings. Several factors must be considered when selecting a protocol: (i) The population being tested and its specific needs in terms of safety, supervision, and accuracy and repeatability of the VO(2max) estimation. (ii) The parameters upon which the prediction is based (e.g. heart rate, power output, rating of perceived exertion [RPE]), as well as the need for additional clinically relevant parameters (e.g. blood pressure, ECG). (iii) The appropriate test modality that should meet the above-mentioned requirements should also be in line with the functional mobility of the target population, and depends on the available equipment. In the sports setting, high repeatability is crucial to track training-induced seasonal changes. In the clinical setting, special attention must be paid to the test modality, because multiple physiological parameters often need to be measured during test execution. When estimating VO(2max), one has

  7. Myocardial oxygen consumption at rest and during submaximal ...

    African Journals Online (AJOL)

    olayemitoyin

    2008-11-26

    Nov 26, 2008 ... ratio were the most important independent parameters in prediction of RPP. The study shows that ... study of various medical, surgical, and physical interventions on .... increase in myocardial activity and thus the MVO2 at rest.

  8. Measurement of forearm oxygen consumption

    DEFF Research Database (Denmark)

    Astrup, A; Simonsen, L; Bülow, J

    1988-01-01

    The classical forearm technique widely used for studies of skeletal muscle metabolism requires arterial cannulation. To avoid arterial puncture it is becoming more common to arterialize blood from a contralateral hand vein by local heating. This modification and the classical method have produced...... blood flow and decreases skeletal muscle blood flow. This facilitates mixing of superficial blood with deep venous blood. Contralateral heating increased deep venous oxygen saturation and abolished the pronounced glucose-induced increase in oxygen consumption observed in the control experiments after...... contradictory results regarding the contribution of skeletal muscle to glucose-induced thermogenesis. The effect on forearm circulation and the metabolism of heating the contralateral hand was examined before and after an oral glucose load. The results suggest that contralateral heating increases subcutaneous...

  9. Do interindividual differences in cardiac output during submaximal exercise explain differences in exercising muscle oxygenation and ratings of perceived exertion?

    Science.gov (United States)

    Bentley, Robert F; Jones, Joshua H; Hirai, Daniel M; Zelt, Joel T; Giles, Matthew D; Raleigh, James P; Quadrilatero, Joe; Gurd, Brendon J; Neder, J Alberto; Tschakovsky, Michael E

    2018-01-01

    Considerable interindividual differences in the Q˙-V˙O2 relationship during exercise have been documented but implications for submaximal exercise tolerance have not been considered. We tested the hypothesis that these interindividual differences were associated with differences in exercising muscle deoxygenation and ratings of perceived exertion (RPE) across a range of submaximal exercise intensities. A total of 31 (21 ± 3 years) healthy recreationally active males performed an incremental exercise test to exhaustion 24 h following a resting muscle biopsy. Cardiac output (Q˙ L/min; inert gas rebreathe), oxygen uptake (V˙O2 L/min; breath-by-breath pulmonary gas exchange), quadriceps saturation (near infrared spectroscopy) and exercise tolerance (6-20; Borg Scale RPE) were measured. The Q˙-V˙O2 relationship from 40 to 160 W was used to partition individuals post hoc into higher (n = 10; 6.3 ± 0.4) versus lower (n = 10; 3.7 ± 0.4, P exercise (all P > 0.4). Lower cardiac responders had greater leg (P = 0.027) and whole body (P = 0.03) RPE only at 185 W, but this represented a higher %peak V˙O2 in lower cardiac responders (87 ± 15% vs. 66 ± 12%, P = 0.005). Substantially lower Q˙-V˙O2 in the lower responder group did not result in altered RPE or exercising muscle deoxygenation. This suggests substantial recruitment of blood flow redistribution in the lower responder group as part of protecting matching of exercising muscle oxygen delivery to demand. © 2018 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  10. Estimation of maximal oxygen uptake via submaximal exercise testing in sports, clinical, and home settings

    NARCIS (Netherlands)

    Sartor, F.; Vernillo, G.; de Morree, H.M.; Bonomi, A.G.; La Torre, A.; Kubis, H.P.; Veicsteinas, A.

    2013-01-01

    Assessment of the functional capacity of the cardiovascular system is essential in sports medicine. For athletes, the maximal oxygen uptake (V˙O2max) provides valuable information about their aerobic power. In the clinical setting, the V˙O2max provides important diagnostic and prognostic information

  11. Oxygenation and EMG in the proximal and distal vastus lateralis during submaximal isometric knee extension

    DEFF Research Database (Denmark)

    Crenshaw, Albert G.; Bronee, Lars; Krag, Ida

    2010-01-01

    /or (2) fatigue development. Nine males performed 2-min sustained isometric knee extensions at 15% and 30% maximum voluntary contraction during which oxygenation and EMG were recorded simultaneously from proximal and distal locations of the vastus lateralis muscle. Near infrared spectroscopy variables...

  12. Application of the allometric scale for the submaximal oxygen uptake in runners and rowers

    Directory of Open Access Journals (Sweden)

    M.P. Tartaruga

    2010-12-01

    Full Text Available Background: The aim of the current study was to determine the allometric exponents for runners and rower’s metabolic cost, while also verifying the relation of performance with and without the allometric application. Methods: Eleven runners (age: 22.3±10.4 years; height: 174±8.8 cm; body mass: 61.7±9.3 kg; maximum oxygen uptake ( •VO2max: 56.3±3.9 ml.kg[sup]-1[/sup].min[sup]-1[/sup] and fifteen rowers (age: 24±5.4 years; height: 185.5±6.5 cm; body mass: 83.5±7.2 kg; •VO2max: 61.2±3.4 ml.kg[sup]-1[/sup].min[sup]-1[/sup] carried out a specific progressive maximum test. The allometric exponent was determined from the logarithmic equation Log y = Log b Log x, where x is the mass, y is the VO2max (l.min[sup]-1[/sup], a is one constant and b is the allometric exponent. The data were analyzed using descriptive and comparative statistics (independent T test of the Student, with p<0.05 (SPSS version 13.0. Results: The allometric exponent of the rowers was 0.70 and that of the runners was 1.00. Significant differences were found between the fat mass percentage, with higher value for rowers, suggesting that this variable may influence the behavior of the allometric exponent and consequently of the basal metabolic rate. Conclusions: Scaling may help in understanding variation in aerobic power and in defining the physiological limitations of work capacity.

  13. Effects of a helium/oxygen mixture on individuals’ lung function and metabolic cost during submaximal exercise for participants with obstructive lung diseases

    Directory of Open Access Journals (Sweden)

    Häussermann S

    2015-09-01

    Full Text Available Sabine Häussermann,1 Anja Schulze,1 Ira M Katz,2,3 Andrew R Martin,4 Christiane Herpich,1 Theresa Hunger,1 Joëlle Texereau2 1Inamed GmbH, Gauting, Germany; 2Medical R&D, Air Liquide Santé International, Centre de Recherche Paris-Saclay, Les Loges-en-Josas, France; 3Department of Mechanical Engineering, Lafayette College, Easton, PA, USA; 4Department of Mechanical Engineering, University of Alberta, Edmonton, AB, CanadaBackground: Helium/oxygen therapies have been studied as a means to reduce the symptoms of obstructive lung diseases with inconclusive results in clinical trials. To better understand this variability in results, an exploratory physiological study was performed comparing the effects of helium/oxygen mixture (78%/22% to that of medical air.Methods: The gas mixtures were administered to healthy, asthmatic, and chronic obstructive pulmonary disease (COPD participants, both moderate and severe (6 participants in each disease group, a total of 30; at rest and during submaximal cycling exercise with equivalent work rates. Measurements of ventilatory parameters, forced spirometry, and ergospirometry were obtained.Results: There was no statistical difference in ventilatory and cardiac responses to breathing helium/oxygen during submaximal exercise. For asthmatics, but not for the COPD participants, there was a statistically significant benefit in reduced metabolic cost, determined through measurement of oxygen uptake, for the same exercise work rate. However, the individual data show that there were a mixture of responders and nonresponders to helium/oxygen in all of the groups.Conclusion: The inconsistent response to helium/oxygen between individuals is perhaps the key drawback to the more effective and widespread use of helium/oxygen to increase exercise capacity and for other therapeutic applications. Keywords: helium/oxygen, inspiratory capacity, oxygen uptake, COPD, asthma, obstructive airway diseases, exercise, heliox

  14. The effect of Sub-maximal exercise-rehabilitation program on cardio-respiratory endurance indexes and oxygen pulse in patients with spastic cerebral palsy

    Directory of Open Access Journals (Sweden)

    M Izadi

    2006-05-01

    Full Text Available Background: Physical or cardio-respiratory fitness are of the best important physiological variables in children with cerebral palsy (CP, but the researches on exercise response of individuals with CP are limited. Our aim was to determine the effect of sub-maximal rehabilitation program (aerobic exercise on maximal oxygen uptake, oxygen pulse and cardio- respiratory physiological variables of children with moderate to severe spastic cerebral palsy diplegia and compare with able-bodied children. Methods: In a controlled clinical trial study, 15 children with diplegia spastic cerebral palsy, were recruited on a voluntarily basis (experimental group and 18 subjects without neurological impairments selected as control group. In CP group, aerobic exercise program performed on the average of exercise intensity (144 beat per minute of heart rate, 3 times a week for 3 months. The time of each exercise session was 20-25 minutes. Dependent variables were measured in before (pretest and after (post test of rehabilitation program through Mac Master Protocol on Tantories cycle ergometer in CP group and compared with the control group. Results: The oxygen pulse (VO2/HR during ergometery protocol was significantly lower in CP group than normal group (P<0.05. No significant statistical difference in maximal oxygen uptake (VO2 max was found between groups. The rehabilitation program leads to little increase of this variable in CP group. After sub-maximal exercise in pretest and post test, the heart rate of patient group was greater than control group, and aerobic exercise leads to significant decrease in heart rate in CP patients(P<0.05. Conclusion: The patients with spastic cerebral palsy, because of high muscle tone, severe spasticity and involuntarily movements have higher energy cost and lower aerobic fitness than normal people. The rehabilitation exercise program can improve physiological function of muscle and cardio-respiratory endurance in these

  15. [The oxygen consumption of ostrich embryos during incubation].

    Science.gov (United States)

    Reiner, G; Dzapo, V

    1995-02-01

    This work deals with the oxygen consumption of ostrich chicks during incubation. Brood eggs were incubated in a hermetic isolated acrylic-glass cylinder. Reduction of oxygen content in the air surrounding the egg was measured using an oxygen-sensitive electrode. A sigmoid curve could be drawn during incubation, with the steepest phase being around day 26. Maximum oxygen consumption was reached on day 36. It was slightly decreased until day 39, when the embryo switches to lung circulation, followed again by an increase until hatching. Average oxygen consumptions for the whole brood interval were calculated to 63.6 liters. Oxygen volumes consumed on day 36 result in a demand about to 240 liters of fresh air per egg and day. Oxygen consumption of the embryos on day 36 was significantly positive correlated with their vitality. Numb or less vital embryos could be clearly differentiated from others. The higher a chick's oxygen consumption, the earlier and shorter its hatching. Possible applications of the method in regard to the evaluation of incubation parameters or chicken constitution are discussed.

  16. Neuromuscular blockade of slow twitch muscle fibres elevates muscle oxygen uptake and energy turnover during submaximal exercise in humans

    DEFF Research Database (Denmark)

    Krustrup, Peter; Secher, Niels; Relu, Mihai U.

    2008-01-01

    We tested the hypothesis that a greater activation of fast-twitch (FT) fibres during dynamic exercise leads to a higher muscle oxygen uptake (VO2 ) and energy turnover as well as a slower muscle on-kinetics. Subjects performed one-legged knee-extensor exercise for 10 min at an intensity of 30 W...... without (CON) and with (CUR) arterial injections of the non-depolarizing neuromuscular blocking agent cisatracurium. In CUR, creatine phosphate (CP) was unaltered in slow twitch (ST) fibres and decreased (P fibres, whereas in CON, CP decreased (P ... at a contraction frequency of 1 Hz, and that the muscle VO2 kinetics is slowed by FT fibre activation....

  17. Neuromuscular blockade of slow twitch muscle fibres elevates muscle oxygen uptake and energy turnover during submaximal exercise in humans.

    Science.gov (United States)

    Krustrup, Peter; Secher, Niels H; Relu, Mihai U; Hellsten, Ylva; Söderlund, Karin; Bangsbo, Jens

    2008-12-15

    We tested the hypothesis that a greater activation of fast-twitch (FT) fibres during dynamic exercise leads to a higher muscle oxygen uptake (VO2 ) and energy turnover as well as a slower muscle on-kinetics. Subjects performed one-legged knee-extensor exercise for 10 min at an intensity of 30 W without (CON) and with (CUR) arterial injections of the non-depolarizing neuromuscular blocking agent cisatracurium. In CUR, creatine phosphate (CP) was unaltered in slow twitch (ST) fibres and decreased (P fibres, whereas in CON, CP decreased (P fibres, respectively. From 127 s of exercise, muscle VO2 was higher (P muscle VO2 response was slower (P muscle homogenate CP was lowered (P muscle lactate production was similar in CUR and CON (37.8 +/- 4.1 versus 35.2 +/- 6.2 mmol). Estimated total muscle ATP turnover was 19% higher (P fibres are less efficient than ST fibres in vivo at a contraction frequency of 1 Hz, and that the muscle VO2 kinetics is slowed by FT fibre activation.

  18. Influence of substrate composition on vitro oxygen consumption of ...

    African Journals Online (AJOL)

    The endogenous oxygen consumption of lung, liver and spleen slices is only slightly increased by glucose in an SRP medium compared with its effect on heart and kidney slices. Individual substrates which induced a highly significant increase in oxygen uptake of lung tissue were succinate, acetate, pyruvate and glucose, ...

  19. Apparatus for the automatic determination of oxygen consumption in ...

    African Journals Online (AJOL)

    An apparatus is described which permits the automatic determination of the oxygen consumption of three fish and a control for 24 hours per day. This is made possible by an electrical control system operating four three-way valves which allow water from one of four respiration chambers at a time to flow past an oxygen ...

  20. Single Cell Oxygen Mapping (SCOM) by Scanning Electrochemical Microscopy Uncovers Heterogeneous Intracellular Oxygen Consumption

    OpenAIRE

    Santos, Carla Santana; Kowaltowski, Alicia J.; Bertotti, Mauro

    2017-01-01

    We developed a highly sensitive oxygen consumption scanning microscopy system using platinized platinum disc microelectrodes. The system is capable of reliably detecting single-cell respiration, responding to classical regulators of mitochondrial oxygen consumption activity as expected. Comparisons with commercial multi-cell oxygen detection systems show that the system has comparable errors (if not smaller), with the advantage of being able to monitor inter and intra-cell heterogeneity in ox...

  1. Patterns of oxygen consumption during simultaneously occurring elevated metabolic states in the viviparous snake Thamnophis marcianus.

    Science.gov (United States)

    Jackson, Alexander G S; Leu, Szu-Yun; Ford, Neil B; Hicks, James W

    2015-11-01

    Snakes exhibit large factorial increments in oxygen consumption during digestion and physical activity, and long-lasting sub-maximal increments during reproduction. Under natural conditions, all three physiological states may occur simultaneously, but the integrated response is not well understood. Adult male and female checkered gartersnakes (Thamnophis marcianus) were used to examine increments in oxygen consumption (i.e. V̇(O2)) and carbon dioxide production (i.e. V̇(CO2)) associated with activity (Act), digestion (Dig) and post-prandial activity (Act+Dig). For females, we carried out these trials in the non-reproductive state, and also during the vitellogenic (V) and embryogenic (E) phases of a reproductive cycle. Endurance time (i.e. time to exhaustion, TTE) was recorded for all groups during Act and Act+Dig trials. Our results indicate that male and non-reproductive female T. marcianus exhibit significant increments in V̇(O2) during digestion (∼5-fold) and activity (∼9-fold), and that Act+Dig results in a similar increment in V̇(O2) (∼9- to 10-fold). During reproduction, resting V̇(O2) increased by 1.6- to 1.7-fold, and peak increments during digestion were elevated by 30-50% above non-reproductive values, but values associated with Act and Act+Dig were not significantly different from non-reproductive values. During Act+Dig, endurance time remained similar for all of the groups in the present study. Overall, our results indicate that prioritization is the primary pattern of interaction in oxygen delivery exhibited by this species. We propose that the metabolic processes associated with digestion, and perhaps reproduction, are temporarily compromised during activity. © 2015. Published by The Company of Biologists Ltd.

  2. Feed intake and oxygen consumption in fish

    NARCIS (Netherlands)

    Subramanian, S.

    2013-01-01

    In fish, the voluntary feed intake is influenced by dietary, environmental and/or physiological factors. It is well known that under hypoxia the concentration of oxygen in the water (DO) determines the feed intake of fish. However at non-limiting water DO levels (normoxia), several other

  3. Sources of variation in oxygen consumption of aquatic animals demonstrated by simulated constant oxygen consumption and respirometers of different sizes

    DEFF Research Database (Denmark)

    Svendsen, Morten Bo Søndergaard; Bushnell, P.G.; Christensen, Emil Aputsiaq Flindt

    2016-01-01

    As intermittent-flow respirometry has become a common method for the determination of resting metabolism or standard metabolic rate (SMR), this study investigated how much of the variability seen in the experiments was due to measurement error. Experiments simulated different constant oxygen cons...... oxygen consumption rates of fishes in systems with reasonable RFRs mainly comes from the animal, not from the measuring equipment....

  4. Circadian rhythm of energy expenditure and oxygen consumption.

    Science.gov (United States)

    Leuck, Marlene; Levandovski, Rosa; Harb, Ana; Quiles, Caroline; Hidalgo, Maria Paz

    2014-02-01

    This study aimed to evaluate the effect of continuous and intermittent methods of enteral nutrition (EN) administration on circadian rhythm. Thirty-four individuals, aged between 52 and 80 years, were fed through a nasoenteric tube. Fifteen individuals received a continuous infusion for 24 hours/d, and 19 received an intermittent infusion in comparable quantities, every 4 hours from 8:00 to 20:00. In each patient, 4 indirect calorimetric measurements were carried out over 24 hours (A: 7:30, B: 10:30, C: 14:30, and D: 21:30) for 3 days. Energy expenditure and oxygen consumption were significantly higher in the intermittent group than in the continuous group (1782 ± 862 vs 1478 ± 817 kcal/24 hours, P = .05; 257 125 vs 212 117 ml/min, P = .048, respectively). The intermittent group had higher levels of energy expenditure and oxygen consumption at all the measured time points compared with the continuous group. energy expenditure and oxygen consumption in both groups were significantly different throughout the day for 3 days. There is circadian rhythm variation of energy expenditure and oxygen consumption with continuous and intermittent infusion for EN. This suggests that only one indirect daily calorimetric measurement is not able to show the patient's true needs. Energy expenditure is higher at night with both food administration methods. Moreover, energy expenditure and oxygen consumption are higher with the intermittent administration method at all times.

  5. The Oxygen Consumption and Metabolic Cost of Walking and Running in Adults With Achondroplasia

    Science.gov (United States)

    Sims, David T.; Onambélé-Pearson, Gladys L.; Burden, Adrian; Payton, Carl; Morse, Christopher I.

    2018-01-01

    The disproportionate body mass and leg length of Achondroplasic individuals may affect their net oxygen consumption (V͘O2) and metabolic cost (C) when walking at running compared to those of average stature (controls). The aim of this study was to measure submaximal V͘O2 and C during a range of set walking speeds (SWS; 0.56 – 1.94 m⋅s-1, increment 0.28 m⋅s-1), set running speeds (SRS; 1.67 – 3.33 m⋅s-1, increment 0.28 m⋅s-1) and a self-selected walking speed (SSW). V͘O2 and C was scaled to total body mass (TBM) and fat free mass (FFM) while gait speed was scaled to leg length using Froude’s number (Fr). Achondroplasic V͘O2TBM and V͘O2FFM were on average 29 and 35% greater during SWS (P 0.05), but CTBM and CFFM at SSW were 23 and 29% higher (P < 0.05) in the Achondroplasic group compared to controls, respectively. V͘O2TBM and V͘O2FFM correlated with Fr for both groups (r = 0.984 – 0.999, P < 0.05). Leg length accounted for the majority of the higher V͘O2TBM and V͘O2FFM in the Achondroplasic group, but further work is required to explain the higher Achondroplasic CTBM and CFFM at all speeds compared to controls. New and Noteworthy: There is a leftward shift of oxygen consumption scaled to total body mass and fat free mass in Achondroplasic adults when walking and running. This is nullified when talking into account leg length. However, despite these scalars, Achondroplasic individuals have a higher walking and metabolic cost compared to age matched non-Achondroplasic individuals, suggesting biomechanical differences between the groups. PMID:29720948

  6. Oxygen consumption by sticklebacks (Gasterosteus aculeatus L. ) exposed to zinc

    Energy Technology Data Exchange (ETDEWEB)

    Brafield, A.E.; Matthiessen, P.

    1976-10-01

    The rate of oxygen consumption by sticklebacks has been studied by long-term continuous-flow respirometry. Exposure to 1 ppM zinc in calcium-free water causes wide variations in individual responses, but oxygen uptake tends to rise and then become extremely erratic, before declining as death approaches. Behavioural abnormalities such as increased ventilation rate, loss of balance, and long periods of inactivity alternating with spasmodic swimming also occur. Exposure to 6.5 ppM zinc in high-calcium water generally causes a rise in oxygen consumption, followed by fluctuations in the rate of uptake, but no behavioural abnormalities occur and deaths are rare even after exposure for 400 h. If restored to zinc-free water after 40 h exposure to zinc, recovery is generally complete, although fluctuating rates of oxygen uptake persist. These results are discussed in relation to previous work on the effects of heavy metals on fish respiration.

  7. Renal transplantation induces mitochondrial uncoupling, increased kidney oxygen consumption, and decreased kidney oxygen tension

    NARCIS (Netherlands)

    Papazova, Diana A.; Friederich-Persson, Malou; Joles, Jaap A.; Verhaar, Marianne C.

    2015-01-01

    Hypoxia is an acknowledged pathway to renal injury and ischemia-reperfusion (I/R) and is known to reduce renal oxygen tension (PO2). We hypothesized that renal I/R increases oxidative damage and induces mitochondrial uncoupling, resulting in increased oxygen consumption and hence kidney

  8. Measurement of oxygen consumption rate of osteoblasts from ...

    African Journals Online (AJOL)

    The cells were evaluated through live/dead assay, hematoxylin-eosin (HE) and alkaline phosphatase (ALP) staining. Moreover, Von-Kossa staining and Alizarin Red S staining were carried out for mineralized nodule formation. Following this, the oxygen consumption rates of osteoblasts in the earlier mentioned different ...

  9. Improving the Accuracy of Predicting Maximal Oxygen Consumption (VO2pk)

    Science.gov (United States)

    Downs, Meghan E.; Lee, Stuart M. C.; Ploutz-Snyder, Lori; Feiveson, Alan

    2016-01-01

    Maximal oxygen (VO2pk) is the maximum amount of oxygen that the body can use during intense exercise and is used for benchmarking endurance exercise capacity. The most accurate method to determineVO2pk requires continuous measurements of ventilation and gas exchange during an exercise test to maximal effort, which necessitates expensive equipment, a trained staff, and time to set-up the equipment. For astronauts, accurate VO2pk measures are important to assess mission critical task performance capabilities and to prescribe exercise intensities to optimize performance. Currently, astronauts perform submaximal exercise tests during flight to predict VO2pk; however, while submaximal VO2pk prediction equations provide reliable estimates of mean VO2pk for populations, they can be unacceptably inaccurate for a given individual. The error in current predictions and logistical limitations of measuring VO2pk, particularly during spaceflight, highlights the need for improved estimation methods.

  10. Restricting glycolysis impairs brown adipocyte glucose and oxygen consumption

    DEFF Research Database (Denmark)

    Winther, Sally; Isidor, Marie Sophie; Basse, Astrid Linde

    2018-01-01

    During thermogenic activation, brown adipocytes take up large amounts of glucose. In addition, cold stimulation leads to an upregulation of glycolytic enzymes. Here we have investigated the importance of glycolysis for brown adipocyte glucose consumption and thermogenesis. Using siRNA-mediated kn......During thermogenic activation, brown adipocytes take up large amounts of glucose. In addition, cold stimulation leads to an upregulation of glycolytic enzymes. Here we have investigated the importance of glycolysis for brown adipocyte glucose consumption and thermogenesis. Using si...... of glycolysis, i.e., hexokinase 2 (HK2) and pyruvate kinase M (PKM), respectively, decreased glucose uptake and ISO-stimulated oxygen consumption. HK2 knockdown had a more severe effect, which, in contrast to PKM knockdown, could not be rescued by supplementation with pyruvate. Hence, brown adipocytes rely...... on glucose consumption and glycolytic flux to achieve maximum thermogenic output, with glycolysis likely supporting thermogenesis not only by pyruvate formation but also by supplying intermediates for efferent metabolic pathways....

  11. Therapeutic effect of forearm low level light treatment on blood flow, oxygenation, and oxygen consumption

    Science.gov (United States)

    Wang, Pengbo; Sun, Jiajing; Meng, Lingkang; Li, Zebin; Li, Ting

    2018-02-01

    Low level light/laser therapy (LLLT) is considered as a novel, non-invasive, and potential therapy in a variety of psychological and physical conditions, due to its effective intricate photobiomodulation. The mechanism of LLLT is that when cells are stimulated by photons, mitochondria produce a large quantity of ATP, which accelerates biochemical responses in the cell. It is of great significance to gain a clear insight into the change or interplay of various physiological parameters. In this study, we used functional near-infrared spectroscopy (fNIRS) and venous-occlusion plethysmography to measure the LLLT-induced changes in blood flow, oxygenation, and oxygen consumption in human forearms in vivo. Six healthy human participants (4 males and 2 females) were administered with 810-nm light emitted by LED array in ten minutes and blood flow, oxygenation and oxygen consumption were detected in the entire experiment. We found that LLLT induced an increase of blood flow and oxygen consumption on the treated site. Meanwhile, LLLT took a good role in promoting oxygenation of regional tissue, which was indicated by a significant increase of oxygenated hemoglobin concentration (Δ[HbO2]), a nearly invariable deoxygenated hemoglobin concentration (Δ[Hb]) and a increase of differential hemoglobin concentration (Δ[HbD] = Δ[HbO2] - Δ[Hb]). These results not only demonstrate enormous potential of LLLT, but help to figure out mechanisms of photobiomodulation.

  12. Effects of motexafin gadolinium on tumor oxygenation and cellular oxygen consumption

    International Nuclear Information System (INIS)

    Donnelly, E.T.; Liu, Y.; Rockwell, S.; Magda, D.

    2003-01-01

    Full text: Recent work in our laboratory showed that motexafin gadolinium (MGd, Xcytrin), a drug currently in Phase III clinical trials as an adjuvant to radiation therapy, modulates the oxygen tensions in EMT6 tumors. The median pO 2 increased from the control value of 1.5±0.4 mmHg to 7.4 ± 3.8 mmHg six hours after treatment with 40 μmol/kg MGd and the percentage of severely hypoxic readings in the tumors ( 7 plateau phase EMT6 cells in 3 mL Dulbecco's Modified Eagle's Medium supplemented with 10% dialyzed fetal bovine serum, which contains no ascorbic acid. In the absence of ascorbic acid, 100 μM MGd did not alter the cellular oxygen consumption rate for EMT6 cells significantly. Marked inhibition of cellular oxygen consumption was observed when cells were incubated with 100 μM MGd in medium supplemented with equimolar ascorbic acid (a 31.5% decrease in consumption was observed after 6 hours of treatment). The 5% mannitol vehicle solution with equimolar ascorbic acid had no discernible effect on cellular oxygen consumption. Ascorbic acid may facilitate cellular uptake of MGd via the intermediate formation of a MGd-oxalate complex. These studies suggest that changes in cellular oxygen consumption could contribute to the changes in tumor oxygenation seen after administration of MGd. These experiments were supported by Pharmacyclics and training grant T32CA09085 from the NIH (E.T.D.). We thank Dr. Raymond Russell for allowing us to use his oxygen electrode apparatus

  13. Oxygen consumption by hydrazine in long sample lines

    International Nuclear Information System (INIS)

    Chi, Lisheng; Turner, Carl-W.

    2012-09-01

    In nuclear power plants secondary side system dissolved oxygen concentration is a strictly controlled chemistry parameter intended to minimize corrosion and fouling of steam cycle components. Low dissolved oxygen concentration is maintained by a combination of mechanical de-aeration and chemical reaction. The dissolved oxygen concentration in feedwater is monitored by sampling systems to ensure it remains within station specification during operation. The sample lines in a nuclear power plant's sampling system can be from 5 to nearly 200 meters in length, resulting in sample residence times between the take-off point to the analyzer from a few seconds to several minutes, depending on the flow rate and the length of the sample line. For many chemical parameters the residence time is of no concern. For measurements of dissolved oxygen and hydrazine in the secondary coolant, however, for residence times longer than one minute, it is uncertain whether the sample is representative of conditions in the secondary coolant, especially for samples taken from locations where the temperature is well over 100 deg. C. To address this concern, a series of tests were conducted under both warm-up and power operation conditions, respectively, to investigate the effect of temperature, residence time, sample line length, surface area, hydrazine-to-oxygen ratio, and the concentrations of dissolved oxygen and hydrazine on the consumption of oxygen by hydrazine. The test results revealed that dissolved oxygen measurements in CANDU plants are underestimated to various degrees, depending on the sampling system operating conditions. Two distinct types of behaviours are observed for the oxygen removal rate: 1) the percentage removal of dissolved oxygen is invariant with time during the tests, and increases with increasing residence time in the test section, when the reaction between hydrazine and oxygen is better described by a homogenous reaction mechanism, and 2) the percentage oxygen

  14. Oxygen consumption in EPDM irradiated under different oxygen pressures and at different LET

    International Nuclear Information System (INIS)

    Dely, N.; Ngono-Ravache, Y.; Ramillon, J.-M.; Balanzat, E.

    2005-01-01

    We conceived a novel set-up for measuring the radiochemical yields of oxygen consumption in polymers. The measurement is based on a sampling of the gas mixture with a mass spectrometer, before and after irradiation. We irradiated an ethylene, propylene and 1,4-hexadiene terpolymer (EPDM) with 1 MeV electron and 10.75 MeV/A carbon beams. Samples were irradiated under oxygen within a wide range of pressure (5-200 mbar). The yields under C irradiation are four times smaller than the yields under electron irradiation. This shows that radiooxidation is very sensitive to the linear energy transfer of the projectiles and hence to the heterogeneity of the energy deposition. The oxygen consumption yields do not vary significantly in the range of pressure investigated; even at 5 mbar, the kinetics is still governed by the bimolecular recombination of peroxy radicals

  15. The Oxygen Consumption and Metabolic Cost of Walking and Running in Adults With Achondroplasia

    Directory of Open Access Journals (Sweden)

    David T. Sims

    2018-04-01

    Full Text Available The disproportionate body mass and leg length of Achondroplasic individuals may affect their net oxygen consumption (V͘O2 and metabolic cost (C when walking at running compared to those of average stature (controls. The aim of this study was to measure submaximal V͘O2 and C during a range of set walking speeds (SWS; 0.56 – 1.94 m⋅s-1, increment 0.28 m⋅s-1, set running speeds (SRS; 1.67 – 3.33 m⋅s-1, increment 0.28 m⋅s-1 and a self-selected walking speed (SSW. V͘O2 and C was scaled to total body mass (TBM and fat free mass (FFM while gait speed was scaled to leg length using Froude’s number (Fr. Achondroplasic V͘O2TBM and V͘O2FFM were on average 29 and 35% greater during SWS (P < 0.05 and 12 and 18% higher during SRS (P < 0.05 than controls, respectively. Achondroplasic CTBM and CFFM were 29 and 33% greater during SWS (P < 0.05 and 12 and 18% greater during SRS (P < 0.05 than controls, respectively. There was no difference in SSW V͘O2TBM or V͘O2FFM between groups (P > 0.05, but CTBM and CFFM at SSW were 23 and 29% higher (P < 0.05 in the Achondroplasic group compared to controls, respectively. V͘O2TBM and V͘O2FFM correlated with Fr for both groups (r = 0.984 – 0.999, P < 0.05. Leg length accounted for the majority of the higher V͘O2TBM and V͘O2FFM in the Achondroplasic group, but further work is required to explain the higher Achondroplasic CTBM and CFFM at all speeds compared to controls.New and Noteworthy: There is a leftward shift of oxygen consumption scaled to total body mass and fat free mass in Achondroplasic adults when walking and running. This is nullified when talking into account leg length. However, despite these scalars, Achondroplasic individuals have a higher walking and metabolic cost compared to age matched non-Achondroplasic individuals, suggesting biomechanical differences between the groups.

  16. Simultaneous sampling of tissue oxygenation and oxygen consumption in skeletal muscle.

    Science.gov (United States)

    Nugent, William H; Song, Bjorn K; Pittman, Roland N; Golub, Aleksander S

    2016-05-01

    Under physiologic conditions, microvascular oxygen delivery appears to be well matched to oxygen consumption in respiring tissues. We present a technique to measure interstitial oxygen tension (PISFO2) and oxygen consumption (VO2) under steady-state conditions, as well as during the transitions from rest to activity and back. Phosphorescence Quenching Microscopy (PQM) was employed with pneumatic compression cycling to achieve 1 to 10 Hz sampling rates of interstitial PO2 and simultaneous recurrent sampling of VO2 (3/min) in the exteriorized rat spinotrapezius muscle. The compression pressure was optimized to 120-130 mmHg without adverse effect on the tissue preparation. A cycle of 5s compression followed by 15s recovery yielded a resting VO2 of 0.98 ± 0.03 ml O2/100 cm(3)min while preserving microvascular oxygen delivery. The measurement system was then used to assess VO2 dependence on PISFO2 at rest and further tested under conditions of isometric muscle contraction to demonstrate a robust ability to monitor the on-kinetics of tissue respiration and the compensatory changes in PISFO2 during contraction and recovery. The temporal and spatial resolution of this approach is well suited to studies seeking to characterize microvascular oxygen supply and demand in thin tissues. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Yeast alter micro-oxygenation of wine: oxygen consumption and aldehyde production.

    Science.gov (United States)

    Han, Guomin; Webb, Michael R; Richter, Chandra; Parsons, Jessica; Waterhouse, Andrew L

    2017-08-01

    Micro-oxygenation (MOx) is a common winemaking treatment used to improve red wine color development and diminish vegetal aroma, amongst other effects. It is commonly applied to wine immediately after yeast fermentation (phase 1) or later, during aging (phase 2). Although most winemakers avoid MOx during malolactic (ML) fermentation, it is often not possible to avoid because ML bacteria are often present during phase 1 MOx treatment. We investigated the effect of common yeast and bacteria on the outcome of micro-oxygenation. Compared to sterile filtered wine, Saccharomyces cerevisiae inoculation significantly increased oxygen consumption, keeping dissolved oxygen in wine below 30 µg L -1 during micro-oxygenation, whereas Oenococcus oeni inoculation was not associated with a significant impact on the concentration of dissolved oxygen. The unfiltered baseline wine also had both present, although with much higher populations of bacteria and consumed oxygen. The yeast-treated wine yielded much higher levels of acetaldehyde, rising from 4.3 to 29 mg L -1 during micro-oxygenation, whereas no significant difference was found between the bacteria-treated wine and the filtered control. The unfiltered wine exhibited rapid oxygen consumption but no additional acetaldehyde, as well as reduced pyruvate. Analysis of the acetaldehyde-glycerol acetal levels showed a good correlation with acetaldehyde concentrations. The production of acetaldehyde is a key outcome of MOx and it is dramatically increased in the presence of yeast, although it is possibly counteracted by the metabolism of O. oeni bacteria. Additional controlled experiments are necessary to clarify the interaction of yeast and bacteria during MOx treatments. Analysis of the glycerol acetals may be useful as a proxy for acetaldehyde levels. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  18. Benthic oxygen consumption on continental shelves off eastern Canada

    Science.gov (United States)

    Grant, Jonathan; Emerson, Craig W.; Hargrave, Barry T.; Shortle, Jeannette L.

    1991-08-01

    The consumption of phytoplankton production by the benthos is an important component of organic carbon budgets for continental shelves. Sediment texture is a major factor regulating benthic processes because fine sediment areas are sites of enhanced deposition from the water column, resulting in increased organic content, bacterial biomass and community metabolism. Although continental shelves at mid- to high latitudes consist primarily of coarse relict sediments ( PIPER, Continental Shelf Research, 11, 1013-1035), shelf regions of boreal and subarctic eastern Canada contain large areas of silt and clay sediments ( FADER, Continental Shelf Research, 11, 1123-1153). We collated estimates of benthic oxygen consumption in coarse (<20% silt-clay, <0.5% organic matter) and fine sediments (20% silt-clay, 0.5% organic matter) for northwest Atlantic continental shelves including new data for Georges Bank, the Scotian Shelf, the Grand Banks of Newfoundland and Labrador Shelf. Estimates were applied to the areal distribution of sediment type on these shelves to obtain a general relationship between sediment texture and benthic carbon consumption. Mean benthic oxygen demand was 2.7 times greater in fine sediment than in coarse sediment, when normalized to mean annual temperature. In terms of carbon equivalents, shelf regions with minimal fine sediment (Georges Bank, the Grand Banks of Newfoundland-northeast Newfoundland) consumed only 5-8% of annual primary production. Benthos of the Gulf of Maine (100% fine sediment) and the Scotian Shelf (35% fine sediment) utilized 16-19% of primary production. Although 32% of the Labrador Shelf area contained fine sediments, benthic consumption of pelagic production (8%) was apparently limited by low mean annual temperature (2°C). These results indicate that incorporation of sediment-specific oxygen uptake into shelf carbon budgets may increase estimates of benthic consumption by 50%. Furthermore, respiration and production by large

  19. Oxygen consumption during exercise in a heated pool.

    Science.gov (United States)

    Kirby, R L; Sacamano, J T; Balch, D E; Kriellaars, D J

    1984-01-01

    The heated hydrotherapy pool is a common exercise site for patients with painful musculoskeletal conditions. Oxygen consumption of swimming is 87 to 89% of maximum in postmyocardial infarction patients according to one recent investigation. We studied 13 able-bodied subjects to test the hypothesis that enough energy could be expended during various forms of hydrotherapy to produce both an aerobic training effect and a risk to patients with coronary artery disease. Oxygen consumption (VO2) was measured in six settings: resting supine; resting seated shoulder deep in the pool (36C); walking at comfortable speed in chest-deep water; running at the fastest speed possible in chest-deep water; using hand paddles; and running in place at shoulder depth. The mean VO2 expressed in ml/kg/min (and metabolic equivalents) were 4.91 (1.00), 4.93 (1.02), 9.34 (2.01), 27.79 (6.23), 18.25 (4.30) and 29.11 (7.09) respectively, suggesting that the more vigorous exercises stress aerobic capacity heavily but not excessively.

  20. Validity of a Newly-Designed Rectilinear Stepping Ergometer Submaximal Exercise Test to Assess Cardiorespiratory Fitness.

    Science.gov (United States)

    Zhang, Rubin; Zhan, Likui; Sun, Shaoming; Peng, Wei; Sun, Yining

    2017-09-01

    The maximum oxygen uptake (V̇O 2 max), determined from graded maximal or submaximal exercise tests, is used to classify the cardiorespiratory fitness level of individuals. The purpose of this study was to examine the validity and reliability of the YMCA submaximal exercise test protocol performed on a newly-designed rectilinear stepping ergometer (RSE) that used up and down reciprocating vertical motion in place of conventional circular motion and giving precise measurement of workload, to determine V̇O 2 max in young healthy male adults. Thirty-two young healthy male adults (32 males; age range: 20-35 years; height: 1.75 ± 0.05 m; weight: 67.5 ± 8.6 kg) firstly participated in a maximal-effort graded exercise test using a cycle ergometer (CE) to directly obtain measured V̇O 2 max. Subjects then completed the progressive multistage test on the RSE beginning at 50W and including additional stages of 70, 90, 110, 130, and 150W, and the RSE YMCA submaximal test consisting of a workload increase every 3 minutes until the termination criterion was reached. A metabolic equation was derived from the RSE multistage exercise test to predict oxygen consumption (V̇O 2 ) from power output (W) during the submaximal exercise test (V̇O 2 (mL·min -1 )=12.4 ×W(watts)+3.5 mL·kg -1 ·min -1 ×M+160mL·min -1 , R 2 = 0.91, standard error of the estimate (SEE) = 134.8mL·min -1 ). A high correlation was observed between the RSE YMCA estimated V̇O 2 max and the CE measured V̇O 2 max (r=0.87). The mean difference between estimated and measured V̇O 2 max was 2.5 mL·kg -1 ·min -1 , with an SEE of 3.55 mL·kg -1 ·min -1 . The data suggest that the RSE YMCA submaximal exercise test is valid for predicting V̇O 2 max in young healthy male adults. The findings show that the rectilinear stepping exercise is an effective submaximal exercise for predicting V̇O 2 max. The newly-designed RSE may be potentially further developed as an alternative ergometer for assessing

  1. Oxygen consumption and blood flow coupling in human motor cortex during intense finger tapping

    DEFF Research Database (Denmark)

    Seyedi Vafaee, Manouchehr; Vang, Kim; Bergersen, Linda H

    2012-01-01

    Rates of cerebral blood flow (CBF) and glucose consumption (CMR(glc)) rise in cerebral cortex during continuous stimulation, while the oxygen-glucose index (OGI) declines as an index of mismatched coupling of oxygen consumption (cerebral metabolic rate of oxygen-CMRO(2)) to CBF and CMR(glc). To t...

  2. Effect of meal and propranolol on whole body and splanchnic oxygen consumption in patients with cirrhosis

    DEFF Research Database (Denmark)

    Krag, Aleksander; Simonsen, Lene; Henriksen, Jens H

    2006-01-01

    Our aim was to measure whole body energy expenditure after a mixed liquid meal, with and without simultaneous propranolol infusion, in patients with cirrhosis. We also wanted to investigate the effect of propranolol on substrate fluxes and oxygen uptake in the tissues drained by the hepatic vein ...... as splanchnic oxygen uptake. The splanchnic reduction in oxygen consumption can explain almost the entire reduction in whole body oxygen consumption....

  3. Effect of music-movement synchrony on exercise oxygen consumption.

    Science.gov (United States)

    Bacon, C J; Myers, T R; Karageorghis, C I

    2012-08-01

    Past research indicates that endurance is improved when exercise movements are synchronised with a musical beat, however it is unclear whether such benefits are associated with reduced metabolic cost. We compared oxygen consumption (.VO2) and related physiological effects of exercise conducted synchronously and asynchronously with music. Three music tracks, each recorded at three different tempi (123, 130, and 137 beats.min-1), accompanied cycle ergometry at 65 pedal revolutions.min-1. Thus three randomly-assigned experimental conditions were administered: slow tempo asynchronous, synchronous, and fast tempo asynchronous. Exercise response of .VO2, HR, and ratings of perceived exertion (RPE), to each condition was monitored in 10 untrained male participants aged 21.7±0.8 years (mean±SD) who cycled for 12 min at 70% maximal heart rate (HR). Mean .VO2 differed among conditions (P=0.008), being lower in the synchronous (1.80±0.22 L.min-1) compared to the slow tempo asynchronous condition (1.94±0.21 L.min-1; Pmusic than when musical tempo is slightly slower than the rate of cyclical movement.

  4. The effect of temperature and salinity on oxygen consumption in the ...

    African Journals Online (AJOL)

    The aquatic oxygen consumption of the estuarine brachyuran crab, Cyclograpsus punctatus, was investigated after a 24-hour acclimation period at different temperature (12.5, 20, 30°C) and salinity (9, 17.5, 35, and 44‰) combinations . Salinity had no significant effect on oxygen consumption at 12.5 and 20°C in both large ...

  5. Recruitment of single muscle fibers during submaximal cycling exercise

    NARCIS (Netherlands)

    Altenburg, T.M.; Degens, H.; van Mechelen, W.; Sargeant, A.J.; de Haan, A.

    2007-01-01

    In literature, an inconsistency exists in the submaximal exercise intensity at which type II fibers are activated. In the present study, the recruitment of type I and II fibers was investigated from the very beginning and throughout a 45-min cycle exercise at 75% of the maximal oxygen uptake, which

  6. Determination of in vitro oxygen consumption rates for tumor cells

    International Nuclear Information System (INIS)

    Cardenas-Navia, L.I.; Moeller, B.J.; Kirkpatrick, J.P.; Laursen, T.A.; Dewhirst, M.W.

    2003-01-01

    To determine pO 2 at the surface of a monolayer of confluent HCT 116 cells, and to then determine consumption rate in vitro by examining the pO 2 profile in media above the cells. Materials and Methods: A recessed-tip polarographic oxygen microelectrode (diameter ∼10μm) was used to measure pO 2 profiles of media above a confluent monolayer of HCT 116 human colon adenocarcinoma cells in a T25 flask exposed to a 95% air, 5% CO 2 mixture. A two-dimensional finite element analysis of the diffusion equation was used to fit the data, thereby extracting a steady-state O 2 consumption rate. The diffusion equation was solved for zeroth and first-order expressions. No-flux boundary conditions were imposed on its bottom and side boundaries and experimental data was used for boundary conditions at the gas-media boundary. All flasks show an O 2 gradient in the media, with a mean (SE) media layer of 1677 (147) μm and a mean pO 2 at the cell layer/media interface of 44 (8) mm Hg (n=9). pO 2 gradient over the entire media layer is 630 (90) mm Hg/cm, equivalent to a consumption rate of 6.3 x 10 -4 (9.0 x 10 -5 ) mm Hg/s. The mean values for the zeroth and first order rate constants are 8.1 x 10 -9 (1.3 x 10 -9 ) g mol O 2 /cm 3 s and 1.0 x 10 3 (0.46 x 10 3 ) /s, respectively. Control experiments in flasks containing no cells show slight gradients in pO 2 of 38 (12) mm Hg/cm, resulting from some O 2 diffusion through the flask into the surrounding water bath. An addition of 10 -3 M NaCN to the media results in a dramatic increase in pO 2 at the cell layer, consistent with a shut-down in respiration. Under normal cell culture conditions there is an O 2 gradient present in the media of cull culture systems, resulting in physiologic O 2 concentrations at the cell layer, despite the non-physiologic O 2 concentration of the gas mixture to which the cell culture system is exposed. This significant (p -6 ) O 2 gradient in the media of cell culture systems is a result of cell O 2

  7. Microgradients of microbial oxygen consumption in a barley rhizosphere model system

    DEFF Research Database (Denmark)

    Højberg, Ole; Sorensen, J.

    1993-01-01

    A microelectrode technique was used to map the radial distribution of oxygen concentrations and oxygen consumption rates around single roots of 7- day-old barley seedlings. The seedlings were grown in gel-stabilized medium containing a nutrient solution, a soil extract, and an inert polymer. Oxygen...... consumption by microbial respiration in the rhizosphere (30 mm from the root) was determined by using Fick's laws of diffusion and an analytical approach with curve fitting to measured microprofiles of oxygen concentration. A marked increase of microbial respiration...... was observed in the inner 0- to 3-mm-thick, concentric zone around the root (rhizosphere). The volume-specific oxygen consumption rate (specific activity) was thus 30 to 60 times higher in the innermost 0 to 0.01 mm (rhizoplane) than in the bulk medium. The oxygen consumption rate in the root tissue...

  8. Maximal Oxygen Consumption is Reduced in Aquaporin-1 Knockout Mice

    Directory of Open Access Journals (Sweden)

    Samer Al-Samir

    2016-08-01

    Full Text Available We have measured maximal oxygen consumption (V’O2,max of mice lacking one or two of the established mouse red-cell CO2 channels AQP1, AQP9 and Rhag. We intended to study whether these proteins, by acting as channels for O2, determine O2 exchange in the lung and in the periphery. We found that V’O2,max as determined by the Helox technique is reduced by ~ 16%, when AQP1 is knocked out, but not when AQP9 or Rhag are lacking. This figure holds for animals respiring normoxic as well as hypoxic gas mixtures. To see whether the reduction of V’O2,max is due to impaired O2 uptake in the lung, we measured carotid arterial O2 saturation (SO2 by pulse oximetry. Neither under normoxic (inspiratory O2 21% nor under hypoxic conditions (11% O2 is there a difference in SO2 between AQP1null and WT mice, suggesting that AQP1 is not critical for O2 uptake in the lung. The fact that the % reduction of V’O2,max is identical in normoxia and hypoxia indicates moreover that the limitation of V’O2,max is not due to an O2 diffusion problem, neither in the lung nor in the periphery. Instead, it appears likely that AQP1null animals exhibit a reduced V’O2,max due to the reduced wall thickness and muscle mass of the left ventricles of their hearts, as reported previously. We conclude that very likely the properties of the hearts of AQP1 knockout mice cause a reduced maximal cardiac output and thus cause a reduced V’O2,max, which constitutes a new phenotype of these mice.

  9. Excess posthypoxic oxygen consumption in rainbow trout (Oncorhynchus mykiss): recovery in normoxia and hypoxia

    DEFF Research Database (Denmark)

    Svendsen, Jon Christian; Steffensen, John Fleng; Aarestrup, Kim

    2012-01-01

    at which the standard metabolic rate becomes dependent upon the ambient oxygen content. Using rainbow trout (Oncorhynchus mykiss (Walbaum, 1792), this study quantified the excess posthypoxic oxygen consumption (EPHOC) occurring after exposure to oxygen availability below S(crit). Tests showed that S...

  10. Physiological modelling of oxygen consumption in birds during flight

    Science.gov (United States)

    Bishop; Butler

    1995-01-01

    This study combines data on changes in cardiovascular variables with body mass (Mb) and with exercise intensity to model the oxygen supply available to birds during flight. Its main purpose is to provide a framework for identifying the factors involved in limiting aerobic power input to birds during flight and to suggest which cardiovascular variables are the most likely to have been influenced by natural selection when considering both allometric and adaptive variation. It is argued that natural selection has acted on heart rate (fh) and cardiac stroke volume (Vs), so that the difference in the arteriovenous oxygen content (CaO2-Cv¯O2) in birds, both at rest and during flight, is independent of Mb. Therefore, the Mb exponent for oxygen consumption (V(dot)O2) during flight can be estimated from measurements of heart rate and stroke volume. Stroke volume is likely to be directly proportional to heart mass (Mh) and, using empirical data, values for the Mb coefficients and exponents of various cardiovascular variables are estimated. It is concluded that, as found for mammals, fh is the main adaptive variable when considering allometric variation, although Mh also shows a slight scaling effect. Relative Mh is likely to be the most important when considering adaptive specialisations. The Fick equation may be represented as: (V(dot)O2)Mbz = (fh)Mbw x (Vs)Mbx x (CaO2 - Cv¯O2)Mby , where w, x, y, z are the body mass exponents for each variable and the terms in parentheses represent the Mb coefficients. Utilising this formula and data from the literature, the scaling of minimum V(dot)O2 during flight for bird species with a 'high aerobic capacity' (excluding hummingbirds) is calculated to be: 166Mb0.77±0.09 = 574Mb-0.19±0.02 x 3.48Mb0.96±0.02 x 0.083Mb0.00±0.05 , and for hummingbirds (considered separately owing to their unique wing kinematics) it is: 314Mb0.90±0.22 = 617Mb-0.10±0.06 x 6.13Mb1.00±0.11 x 0.083Mb0.00±0.05 . These results are largely dependent on the

  11. Oxygen uptake efficiency slope and peak oxygen consumption predict prognosis in children with tetralogy of Fallot.

    Science.gov (United States)

    Tsai, Yun-Jeng; Li, Min-Hui; Tsai, Wan-Jung; Tuan, Sheng-Hui; Liao, Tin-Yun; Lin, Ko-Long

    2016-07-01

    Oxygen uptake efficiency slope (OUES) and peak oxygen consumption (VO2peak) are exercise parameters that can predict cardiac morbidity in patients with numerous heart diseases. But the predictive value in patients with tetralogy of Fallot is still undetermined, especially in children. We evaluated the prognostic value of OUES and VO2peak in children with total repair of tetralogy of Fallot. Retrospective cohort study. Forty tetralogy of Fallot patients younger than 12 years old were recruited. They underwent a cardiopulmonary exercise test during the follow-up period after total repair surgery. The results of the cardiopulmonary exercise test were used to predict the cardiac related hospitalization in the following two years after the test. OUES normalized by body surface area (OUES/BSA) and the percentage of predicted VO2peak appeared to be predictive for two-year cardiac related hospitalization. Receiver operating characteristic curve analysis demonstrated that the best threshold value for OUES/BSA was 1.029 (area under the curve = 0.70, p = 0.03), and for VO2peak was 74% of age prediction (area under the curve = 0.72, p = 0.02). The aforementioned findings were confirmed by Kaplan-Meier plots and log-rank test. OUES/BSA and VO2peak are useful predictors of cardiac-related hospitalization in children with total repair of tetralogy of Fallot. © The European Society of Cardiology 2015.

  12. Relations of morphological characteristics and maximal oxygen consumption of fourth grade pupils based on gender

    Directory of Open Access Journals (Sweden)

    Jakovljević Vladimir

    2014-01-01

    Full Text Available On a sample of 71 respondents, 37 boys and 34 girls, age of fourth grade elementary school, accordingly 9 years +/- 6 months, it is assessed correlation and prediction of maximal oxygen consumption based measures of morphological range. Maximum oxygen consumption was measured by indirect method, using a field test of maximal multiple load of feedback running at 20 meters. Range of morphology was analyzed based on 5 measures of longitudinal dimensionality, 4 measures of volume and body mass and 3 measures of transversal dimensionality. Results of correlation analysis showed that in both sexes there was no statistically significant correlation between results of maximal oxygen consumption and measures of longitudinal dimensionality, while regression analysis confirmed that there was no statistically significant prediction of maximum oxygen consumption based on measures of longitudinal dimensionality. While the correlation analysis deduced that part of volume measures and body mass and transversal dimensionality have statistically significant correlation only with female respondents with results of maximal oxygen consumption. Regression analysis showed statistically significant prediction of maximal oxygen consumption based on part of volume measures and body mass and transversal dimensionality. It is determined that female respondents with larger volumes of the thigh and lower leg, accordingly with smaller diameters of knee joint and ankle joint most likely will achieve better results in applied test, and therefore higher maximal oxygen consumption.

  13. Reduced peripheral arterial blood flow with preserved cardiac output during submaximal bicycle exercise in elderly heart failure

    Directory of Open Access Journals (Sweden)

    Leng Xiaoyan

    2009-11-01

    Full Text Available Abstract Background Older heart failure (HF patients exhibit exercise intolerance during activities of daily living. We hypothesized that reduced lower extremity blood flow (LBF due to reduced forward cardiac output would contribute to submaximal exercise intolerance in older HF patients. Methods and Results Twelve HF patients both with preserved and reduced left ventricular ejection fraction (LVEF (aged 68 ± 10 years without large (aorta or medium sized (iliac or femoral artery vessel atherosclerosis, and 13 age and gender matched healthy volunteers underwent a sophisticated battery of assessments including a peak exercise oxygen consumption (peak VO2, b physical function, c cardiovascular magnetic resonance (CMR submaximal exercise measures of aortic and femoral arterial blood flow, and d determination of thigh muscle area. Peak VO2 was reduced in HF subjects (14 ± 3 ml/kg/min compared to healthy elderly subjects (20 ± 6 ml/kg/min (p = 0.01. Four-meter walk speed was 1.35 ± 0.24 m/sec in healthy elderly verses 0.98 ± 0.15 m/sec in HF subjects (p p ≤ 0.03. Conclusion During CMR submaximal bike exercise in the elderly with heart failure, mechanisms other than low cardiac output are responsible for reduced lower extremity blood flow.

  14. Preliminary Study on the Oxygen Consumption Dynamics During Brain Hypothermia Resuscitation

    National Research Council Canada - National Science Library

    Ji, Yan

    2001-01-01

    .... Two cooling approaches (the surface cooling and volumetric cooling are applied to analyze the effect of hypothermia on the transient temperature and the oxygen consumption rate in different regions of brain...

  15. Comparative oxygen consumption rates of subitaneous and delayed hatching eggs of the calanoid copepod Acartia tonsa (Dana)

    DEFF Research Database (Denmark)

    Hansen, Benni Winding; Drillet, Guillaume

    2013-01-01

    nanorespirometry to monitor initial oxygen consumption rate of individual eggs of the ubiquitous neritic calanoid copepod Acartia tonsa to distinguish between subitaneous and DHE. We hypothesized that subitaneous eggs exhibit higher initial oxygen consumption rates than DHE, and that initial egg oxygen consumption...... rate is correlated to the time for the individual egg to hatch. Subitaneous eggs exhibited higher initial oxygen consumption rates than DHE and there were no pattern in initial oxygen consumption rates vs. time to hatch or die from the eggs. Variability in initial oxygen consumption rates within...... batches of both subitaneous and DHE, as well as between these egg types, is prevalent. There was a continuum from sluggish- to fast metabolising eggs considering initial oxygen consumption rates most likely reflecting phenotypic variation within cohorts. No matter the individual initial egg oxygen...

  16. Oxygen consumption and responses of the freshwater snail Bulinus ...

    African Journals Online (AJOL)

    behaviour to oxygen differences in the water is of special interest. Knowledge of this ... fold, the prosobranch, to enhance the gaseous exchange between the animal ..... meins that little stress on the respiration ability was encountered towards ...

  17. Measurement of oxygen consumption rate of osteoblasts from ...

    African Journals Online (AJOL)

    Jane

    2011-05-10

    May 10, 2011 ... E-mail: kedongsong@dlut.edu.cn. Tel: +86 411 ... the experiments, including inverted phase contrast microscope. (IX70-Olympus ... The pictures showed that the osteoblasts still had very high cellular viability. consumption of ...

  18. Oxygen consumption rates by different oenological tannins in a model wine solution.

    Science.gov (United States)

    Pascual, Olga; Vignault, Adeline; Gombau, Jordi; Navarro, Maria; Gómez-Alonso, Sergio; García-Romero, Esteban; Canals, Joan Miquel; Hermosín-Gutíerrez, Isidro; Teissedre, Pierre-Louis; Zamora, Fernando

    2017-11-01

    The kinetics of oxygen consumption by different oenological tannins were measured in a model wine solution using the non-invasive method based on luminiscence. The results indicate that the oxygen consumption rate follows second-order kinetics depending on tannin and oxygen concentrations. They also confirm that the oxygen consumption rate is influenced by temperature in accordance with Arrhenius law. The indications are that ellagitannins are the fastest oxygen consumers of the different oenological tannins, followed in decreasing order by quebracho tannins, skin tannins, seed tannins and finally gallotannins. This methodology can therefore be proposed as an index for determining the effectiveness of different commercial tannins in protecting wines against oxidation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Biotite dissolution and oxygen consumption in aqueous media at 100 degrees C

    International Nuclear Information System (INIS)

    Taylor, P.; Owen, D.G.

    1997-04-01

    The ability of biotite to consume dissolved oxygen, and hence restore reducing conditions in a nuclear fuel waste vault after closure, has been assessed experimentally. Oxygen consumption has been measured directly, and also deduced from experimental biotite dissolution rates. Results from the dissolution experiments on granitic biotite from the Lac du Bonnet region, Manitoba indicate that the biotite component of granite backfill should consume entrained oxygen in about 50 years at 100 degrees C. Direct measurements of oxygen consumption by commercial biotite specimens originating from Bancroft, Ontario were reasonably consistent with this finding. Magnetite is significantly more effective than biotite at oxygen consumption, perhaps two orders of magnitude faster at 100 degrees C. (author)

  20. Effects of extracellular zinc ion on the rate of oxygen consumption of ...

    African Journals Online (AJOL)

    The inhibitory effect of extracellular zinc ion on the rate of oxygen consumption of rat brain mitochondria pre-incubated in 1.0 mM Ca2+EDTA were determined. There was a significant increase [P<0.01] in the rate of oxygen consumption in the rat brain mitochondria pre-incubated in 1.0 mM. Ca2+EDTA in a succinate ...

  1. Excess post-hypoxic oxygen consumption is independent from lactate accumulation in two cyprinid fishes

    DEFF Research Database (Denmark)

    Genz, J.; Jyde, M.B.; Svendsen, Jon Christian

    2013-01-01

    the increase in oxygen consumption in fish required following strenuous exercise or low environmental oxygen availability has been frequently considered, the primary contributing mechanism remains unknown. This study utilized the close relationship but strongly divergent physiology between C. carpio and C...

  2. Oxygen consumption through metabolism and photodynamic reactions in cells cultured on microbeads

    International Nuclear Information System (INIS)

    Schunck, T.; Poulet, P.

    2000-01-01

    Oxygen consumption by cultured cells, through metabolism and photosensitization reactions, has been calculated theoretically. From this result, we have derived the partial oxygen pressure P O 2 in the perfusion medium flowing across sensitized cultured cells during photodynamic experiments. The P O 2 variations in the perfusate during light irradiation are related to the rate of oxygen consumption through photoreactions, and to the number of cells killed per mole of oxygen consumed through metabolic processes. After irradiation, the reduced metabolic oxygen consumption yields information on the cell death rate, and on the photodynamic cell killing efficiency. The aim of this paper is to present an experimental set-up and the corresponding theoretical model that allows us to control the photodynamic efficiency for a given cell-sensitizer pair, under well defined and controlled conditions of irradiation and oxygen supply. To demonstrate the usefulness of the methodology described, CHO cells cultured on microbeads were sensitized with pheophorbide a and irradiated with different light fluence rates. The results obtained, i.e. oxygen consumption of about 0.1 μMs -1 m -3 under a light fluence rate of 1 W m -2 , 10 5 cells killed per mole of oxygen consumed and a decay rate of about 1 h -1 of living cells after irradiation, are in good agreement with the theoretical predictions and with previously published data. (author)

  3. Effect of selective blockade of oxygen consumption, glucose transport, and Ca2+ influx on thyroxine action in human mononuclear cells

    DEFF Research Database (Denmark)

    Kvetny, J; Matzen, L E

    1990-01-01

    The effect of selective blockade of cellular glucose transporters, Ca2+ influx, and mitochondrial oxygen consumption on thyroxine (T4)-stimulated oxygen consumption and glucose uptake was examined in human mononuclear blood cells. Blockade of glucose transporters by cytochalasin B (1 x 10(-5) mol....../L) and of Ca2+ influx by alprenolol (1 x 10(-5) mol/L) and verapamil (4 x 10(-4) mol/L) inhibited T4-activated glucose uptaken and reduced T4-stimulated oxygen consumption by 20%. Uncoupling of mitochondrial oxygen consumption by azide (1 x 10(-3) mol/L) inhibited T4-stimulated oxygen consumption, but had...... no effect on glucose uptake. We conclude that T4-stimulated glucose uptake in human mononuclear blood cells is dependent on intact glucose transporters and Ca2+ influx, but not on mitochondrial oxygen consumption. However, oxygen consumption is, in part, dependent on intact glucose uptake....

  4. Fine mapping of a QTL on chromosome 13 for submaximal exercise capacity training response: the HERITAGE Family Study.

    Science.gov (United States)

    Rice, Treva K; Sarzynski, Mark A; Sung, Yun Ju; Argyropoulos, George; Stütz, Adrian M; Teran-Garcia, Margarita; Rao, D C; Bouchard, Claude; Rankinen, Tuomo

    2012-08-01

    Although regular exercise improves submaximal aerobic capacity, there is large variability in its response to exercise training. While this variation is thought to be partly due to genetic differences, relatively little is known about the causal genes. Submaximal aerobic capacity traits in the current report include the responses of oxygen consumption (ΔVO(2)60), power output (ΔWORK60), and cardiac output (ΔQ60) at 60% of VO2max to a standardized 20-week endurance exercise training program. Genome-wide linkage analysis in 475 HERITAGE Family Study Caucasians identified a locus on chromosome 13q for ΔVO(2)60 (LOD = 3.11). Follow-up fine mapping involved a dense marker panel of over 1,800 single-nucleotide polymorphisms (SNPs) in a 7.9-Mb region (21.1-29.1 Mb from p-terminus). Single-SNP analyses found 14 SNPs moderately associated with both ΔVO(2)60 at P ≤ 0.005 and the correlated traits of ΔWORK60 and ΔQ60 at P < 0.05. Haplotype analyses provided several strong signals (P < 1.0 × 10(-5)) for ΔVO(2)60. Overall, association analyses narrowed the target region and included potential biological candidate genes (MIPEP and SGCG). Consistent with maximal heritability estimates of 23%, up to 20% of the phenotypic variance in ΔVO(2)60 was accounted for by these SNPs. These results implicate candidate genes on chromosome 13q12 for the ability to improve submaximal exercise capacity in response to regular exercise. Submaximal exercise at 60% of maximal capacity is an exercise intensity that falls well within the range recommended in the Physical Activity Guidelines for Americans and thus has potential public health relevance.

  5. Influence of Substrate Composition on vitro Oxygen Consumption of ...

    African Journals Online (AJOL)

    1974-09-11

    Sep 11, 1974 ... and it activates the angiotensin sys- tem by converting angiotensin I to angiotensin n.l3 It also participates in the de 110\\10 synthesis of fatty acids," pro- teins" and of phospholipids (surfactant)." The oxygen consumed by the lung is used not only for its own basal metabolic needs but for additional metabolic.

  6. Uptake rate of cationic mitochondrial inhibitor MKT-077 determines cellular oxygen consumption change in carcinoma cells.

    Directory of Open Access Journals (Sweden)

    John L Chunta

    Full Text Available OBJECTIVE: Since tumor radiation response is oxygen-dependent, radiosensitivity can be enhanced by increasing tumor oxygenation. Theoretically, inhibiting cellular oxygen consumption is the most efficient way to increase oxygen levels. The cationic, rhodacyanine dye-analog MKT-077 inhibits mitochondrial respiration and could be an effective metabolic inhibitor. However, the relationship between cellular MKT-077 uptake and metabolic inhibition is unknown. We hypothesized that rat and human mammary carcinoma cells would take up MKT-077, causing a decrease in oxygen metabolism related to drug uptake. METHODS: R3230Ac rat breast adenocarcinoma cells were exposed to MKT-077. Cellular MKT-077 concentration was quantified using spectroscopy, and oxygen consumption was measured using polarographic electrodes. MKT-077 uptake kinetics were modeled by accounting for uptake due to both the concentration and potential gradients across the plasma and mitochondrial membranes. These kinetic parameters were used to model the relationship between MKT-077 uptake and metabolic inhibition. MKT-077-induced changes in oxygen consumption were also characterized in MDA-MB231 human breast carcinoma cells. RESULTS: Cells took up MKT-077 with a time constant of ∼1 hr, and modeling showed that over 90% of intracellular MKT-077 was bound or sequestered, likely by the mitochondria. The uptake resulted in a rapid decrease in oxygen consumption, with a time constant of ∼30 minutes. Surprisingly the change in oxygen consumption was proportional to uptake rate, not cellular concentration. MKT-077 proved a potent metabolic inhibitor, with dose-dependent decreases of 45-73% (p = 0.003. CONCLUSIONS: MKT-077 caused an uptake rate-dependent decrease in cellular metabolism, suggesting potential efficacy for increasing tumor oxygen levels and radiosensitivity in vivo.

  7. Differences in temperature, organic carbon and oxygen consumption among lowland streams

    DEFF Research Database (Denmark)

    Sand-Jensen, K.; Pedersen, N. L.

    2005-01-01

    1. Temperature, organic carbon and oxygen consumption were measured over a year at 13 sites in four lowlands streams within the same region in North Zealand, Denmark with the objectives of determining: (i) spatial and seasonal differences between open streams, forest streams and streams with or w......1. Temperature, organic carbon and oxygen consumption were measured over a year at 13 sites in four lowlands streams within the same region in North Zealand, Denmark with the objectives of determining: (i) spatial and seasonal differences between open streams, forest streams and streams...... the exponential increase of oxygen consumption rate between 4 and 20 °C averaged 0.121 °C-1 (Q10 of 3.35) in 70 measurements and showed no significant variations between seasons and stream sites or correlations with ambient temperature and organic content. 5. Oxygen consumption rate was enhanced downstream...... at ambient temperature by 30-40% and 80-130%, respectively. Faster consumption of organic matter and dissolved oxygen downstream of point sources should increase the likelihood of oxygen stress of the stream biota and lead to the export of less organic matter but more mineralised nutrients to the coastal...

  8. Measurement of oxygen consumption during muscle flaccidity exercise by near-infrared spectroscopy

    Science.gov (United States)

    Fukuda, K.; Fukawa, Y.

    2013-03-01

    Quantitative measurement oxygen consumption in the muscles is important to evaluate the effect of the exercise. Near-infrared spectroscopy (NIRS) is a noninvasive method for measuring muscle oxygenation. However, measurement results are affected by blood volume change due to changes in the blood pressure. In order to evaluate changes in blood volume and to improve measurement accuracy, we proposed a calculation method of three-wavelength measurement with considering the scattering factor and the measurement with monitoring blood flow for measuring the temporal change of the oxygen concentration more precisely. We applied three-wavelength light source (680nm, 808nm and 830nm) for the continued wave measurement. Two detectors (targeted detector and the reference detector) were placed near the target muscle and apart from it. We measured the blood flow by controlling the intravascular pressure and the oxygen consumption with the handgrip exercise in the forearm. The measured results show that the scattering factor contains the artifact at the surface and the blood flow in the artery and the vein in the same phase. The artifact and the blood flow in the same phase are reduced from the oxygenated and the deoxygenated hemoglobin densities. Thus our proposed method is effective for reducing the influence of the artifact and the blood flow in the same phase from the oxygen consumption measurement. Further, it is shown that the oxygen consumption is measured more accurately by subtracting the blood flow measured by the reference detector.

  9. Ventilation and oxygen consumption in the hagfish, Myxine glutinosa L

    DEFF Research Database (Denmark)

    STEFFENSEN, JF; JOHANSEN, K; SINDBERG, CD

    1984-01-01

    Ventilation was measured directly in the hagfish, Myxine glutinosa L., by means of an electro-magnetic blood flowmeter. Ventilatory flow and frequency increased from 0.86 ± 0.27 mlmin-, and 18.2 ± 5.1min-, respectively, at 7°C to 1.70 ± 0.20 mlmin-, and 70.1 ± 9.5min- at 15 C. Standard oxygen...

  10. Pump speed modulations and sub-maximal exercise tolerance in left ventricular assist device recipients

    DEFF Research Database (Denmark)

    Jung, Mette Holme; Houston, Brian; Russell, Stuart D

    2017-01-01

    of the 2 sub-maximal tests was determined by randomization. Both patient and physician were blinded to the sequence. Exercise duration, oxygen consumption (VO2) and rate of perceived exertion (RPE), using the Borg scale (score 6 to 20), were recorded. RESULTS: Nineteen patients (all with a HeartMate II...... ventricular assist device) completed 57 exercise tests. Baseline pump speed was 9,326 ± 378 rpm. At AT, workload was 63 ± 26 W (25 to 115 W) and VO2 was 79 ± 14% of maximum. Exercise duration improved by 106 ± 217 seconds (~13%) in Speedinc compared with Speedbase (837 ± 358 vs 942 ± 359 seconds; p = 0...

  11. Validity of a Newly-Designed Rectilinear Stepping Ergometer Submaximal Exercise Test to Assess Cardiorespiratory Fitness

    OpenAIRE

    Rubin Zhang, Likui Zhan, Shaoming Sun, Wei Peng, Yining Sun

    2017-01-01

    The maximum oxygen uptake (V̇O2 max), determined from graded maximal or submaximal exercise tests, is used to classify the cardiorespiratory fitness level of individuals. The purpose of this study was to examine the validity and reliability of the YMCA submaximal exercise test protocol performed on a newly-designed rectilinear stepping ergometer (RSE) that used up and down reciprocating vertical motion in place of conventional circular motion and giving precise measurement of workload, to det...

  12. Effect of a High-intensity Interval Training method on maximum oxygen consumption in Chilean schoolchildren

    Directory of Open Access Journals (Sweden)

    Sergio Galdames-Maliqueo

    2017-12-01

    Full Text Available Introduction: The low levels of maximum oxygen consumption (VO2max evaluated in Chilean schoolchildren suggest the startup of trainings that improve the aerobic capacity. Objective: To analyze the effect of a High-intensity Interval Training method on maximum oxygen consumption in Chilean schoolchildren. Materials and methods: Thirty-two high school students from the eighth grade, who were divided into two groups, were part of the study (experimental group = 16 students and control group = 16 students. The main analyzed variable was the maximum oxygen consumption through the Course Navette Test. A High-intensity Interval training method was applied based on the maximum aerobic speed obtained through the Test. A mixed ANOVA was used for statistical analysis. Results: The experimental group showed a significant increase in the Maximum Oxygen Consumption between the pretest and posttest when compared with the control group (p < 0.0001. Conclusion: The results of the study showed a positive effect of the High-intensity Interval Training on the maximum consumption of oxygen. At the end of the study, it is concluded that High-intensity Interval Training is a good stimulation methodology for Chilean schoolchildren.

  13. Oxygen consumption rate and mitochondrial density in human melanoma monolayer cultures and multicellular spheroids.

    Science.gov (United States)

    Hystad, M E; Rofstad, E K

    1994-05-15

    Rate of oxygen consumption per cell has been shown in previous studies to decrease with increasing depth in the viable rim of multicellular spheroids initiated from rodent cells, human colon-carcinoma cells, and human glioma cells, due to progressive accumulation of quiescent cells during spheroid growth. The purpose of our work was to determine oxygen-consumption profiles in human melanoma spheroids. Monolayer cultures of 4 lines (BEX-c, COX-c, SAX-c, and WIX-c) and spheroid cultures of 2 lines (BEX-c and WIX-c) were subjected to investigation. Spheroids were initiated from monolayer cell cultures and grown in spinner flasks. Rate of oxygen consumption was measured with a Clarke-type electrode. Mitochondrial density was determined by stereological analysis of transmission electron micrographs. Thickness of viable rim and cell packing density were assessed by light microscopy of central spheroid sections. Cell-cycle distribution was determined by analysis of DNA histograms measured by flow cytometry. Cell volume was measured by an electronic particle counter. Rate of oxygen consumption per cell differed by a factor of approximately 1.8 between the 4 cell lines and was positively correlated to total volume of mitochondria per cell. Rate of oxygen consumption per cell and total volume of mitochondria per cell were equal for monolayer cell cultures, 600-microns spheroids and 1,200-microns spheroids of the same line. Mitochondrial density and location in the cell did not differ between cells at the spheroid surface, in the middle of the viable rim and adjacent to the central necrosis. Cell-cycle distribution, cell volume, and cell-packing density in the outer and inner halves of the viable rim were not significantly different. Consequently, the rate of oxygen consumption per cell in inner regions of the viable rim was probably equal to that at the spheroid surface, suggesting that oxygen diffusion distances may be shorter in some melanomas than in many other tumor

  14. Estimate of oxygen consumption and intracellular zinc concentration of human spermatozoa in relation to motility.

    Science.gov (United States)

    Henkel, Ralf R; Defosse, Kerstin; Koyro, Hans-Wilhelm; Weissmann, Norbert; Schill, Wolf-Bernhard

    2003-03-01

    To investigate the human sperm oxygen/energy consumption and zinc content in relation to motility. In washed spermatozoa from 67 ejaculates, the oxygen consumption was determined. Following calculation of the total oxygen consumed by the Ideal Gas Law, the energy consumption of spermatozoa was calculated. In addition, the zinc content of the sperm was determined using an atomic absorption spectrometer. The resulting data were correlated to the vitality and motility. The oxygen consumption averaged 0.24 micromol/10(6) sperm x 24h, 0.28 micromol/10(6) live sperm x 24h and 0.85 micromol/10(6) live motile sperm x 24h. Further calculations revealed that sperm motility was the most energy consuming process (164.31 mJ/10(6) motile spermatozoa x 24h), while the oxygen consumption of the total spermatozoa was 46.06 mJ/10(6) spermatozoa x 24h. The correlation of the oxygen/energy consumption and zinc content with motility showed significant negative correlations (r= -0.759; P<0.0001 and r=-0.441; P<0.0001, respectively). However, when correlating sperm energy consumption with the zinc content, a significant positive relation (r=0.323; P=0.01) was observed. Poorly motile sperm are actually wasting the available energy. Moreover, our data clearly support the "Geometric Clutch Model" of the axoneme function and demonstrate the importance of the outer dense fibers for the generation of sperm motility, especially progressive motility.

  15. Variable ATP yields and uncoupling of oxygen consumption in human brain

    DEFF Research Database (Denmark)

    Gjedde, Albert; Aanerud, Joel; Peterson, Ericka

    2011-01-01

    normalized the metabolic rate to the population average of that region. Coefficients of variation ranged from 10 to 15% in the different regions of the human brain and the normalized regional metabolic rates ranged from 70% to 140% of the population average for each region, equal to a two-fold variation......The distribution of brain oxidative metabolism values among healthy humans is astoundingly wide for a measure that reflects normal brain function and is known to change very little with most changes of brain function. It is possible that the part of the oxygen consumption rate that is coupled...... to ATP turnover is the same in all healthy human brains, with different degrees of uncoupling explaining the variability of total oxygen consumption among people. To test the hypothesis that about 75% of the average total oxygen consumption of human brains is common to all individuals, we determined...

  16. Oxygen Consumption of Tilapia and Preliminary Mass Flows through a Prototype Closed Aquaculture System

    Science.gov (United States)

    Muller, Matthew S.; Bauer, Clarence F.

    1994-01-01

    Performance of NASA's prototype CELSS Breadboard Project Closed Aquaculture System was evaluated by estimating gas exchange quantification and preliminary carbon and nitrogen balances. The total system oxygen consumption rate was 535 mg/hr kg/fish (cv = 30%) when stocked with Tilapia aurea populations (fresh weights of 97 +/- 19 to 147 +/- 36 g/fish for various trials). Oxygen consumption by T. aurea (260 mg/hr kg/fish) contributed to approximately one-half of total system demand. Continuous carbon dioxide quantification methods were analyzed using the,relation of carbon dioxide to oxygen consumption. Overall food conversion rates averaged 18.2 +/- 3.2%. Major pathways for nitrogen and carbon in the system were described with preliminary mass closure of 60-80% and 60% for nitrogen and carbon.

  17. Low doses of caffeine reduce heart rate during submaximal cycle ergometry

    Directory of Open Access Journals (Sweden)

    Wetter Thomas J

    2007-10-01

    Full Text Available Abstract Background The purpose of this study was to examine the cardiovascular effects of two low-levels of caffeine ingestion in non habitual caffeine users at various submaximal and maximal exercise intensities. Methods Nine male subjects (19–25 yr; 83.3 ± 3.1 kg; 184 ± 2 cm, underwent three testing sessions administered in a randomized and double-blind fashion. During each session, subjects were provided 4 oz of water and a gelatin capsule containing a placebo, 1.5 mg/kg caffeine, or 3.0 mg/kg caffeine. After thirty minutes of rest, a warm-up (30 Watts for 2 min the pedal rate of 60 rpm was maintained at a steady-state output of 60 watts for five minutes; increased to 120 watts for five minutes and to 180 watts for five minutes. After a 2 min rest the workload was 180 watts for one minute and increased by 30 watts every minute until exhaustion. Heart rate (HR was measured during the last 15-seconds of each minute of submaximal exercise. Systolic blood pressure (BP was measured at rest and during each of the three sub-maximal steady state power outputs. Minute ventilation (VE, Tidal volume (VT, Breathing frequency (Bf, Rating of perceived exertion (RPE, Respiratory exchange ratio (RER, and Oxygen consumption (VO2 were measured at rest and during each minute of exercise. Results Caffeine at 1.5 and 3.0 mg/kg body weight significantly lowered (p E, VT, VO2, RPE, maximal power output or time to exhaustion. Conclusion In non habitual caffeine users it appears that consuming a caffeine pill (1.5 & 3.0 mg/kg at a dose comparable to 1–3 cups of coffee lowers heart rate during submaximal exercise but not at near maximal and maximal exercise. In addition, this caffeine dose also only appears to affect systolic blood pressure at rest but not during cycling exercise.

  18. Aerobic composting of waste activated sludge: Kinetic analysis for microbiological reaction and oxygen consumption

    International Nuclear Information System (INIS)

    Yamada, Y.; Kawase, Y.

    2006-01-01

    In order to examine the optimal design and operating parameters, kinetics for microbiological reaction and oxygen consumption in composting of waste activated sludge were quantitatively examined. A series of experiments was conducted to discuss the optimal operating parameters for aerobic composting of waste activated sludge obtained from Kawagoe City Wastewater Treatment Plant (Saitama, Japan) using 4 and 20 L laboratory scale bioreactors. Aeration rate, compositions of compost mixture and height of compost pile were investigated as main design and operating parameters. The optimal aerobic composting of waste activated sludge was found at the aeration rate of 2.0 L/min/kg (initial composting mixture dry weight). A compost pile up to 0.5 m could be operated effectively. A simple model for composting of waste activated sludge in a composting reactor was developed by assuming that a solid phase of compost mixture is well mixed and the kinetics for microbiological reaction is represented by a Monod-type equation. The model predictions could fit the experimental data for decomposition of waste activated sludge with an average deviation of 2.14%. Oxygen consumption during composting was also examined using a simplified model in which the oxygen consumption was represented by a Monod-type equation and the axial distribution of oxygen concentration in the composting pile was described by a plug-flow model. The predictions could satisfactorily simulate the experiment results for the average maximum oxygen consumption rate during aerobic composting with an average deviation of 7.4%

  19. Manual handling methods evaluation based on oxygen consumption

    Science.gov (United States)

    Nurmianto, E.; Ciptomulyono, U.; Suparno; Kromodihardjo, S.; Setijono, H.; Arief, N. A.

    2018-04-01

    Mining industry has become one of the largest industries in Indonesia, now competing in billions dollar market, with numbers people employed. Deliveries of a Return Rolls (RR) involve the use of a hand truck and, in many cases, a shoulder/elbow-mode of carriage. Workers usually prefer to the Gendong (carrying on the small of the back or the hip, supported by the waist and arm) mode or Manggul (carrying on some stuff shoulder) mode, because they feel safer by carrying RR on the shoulder/elbow. In this study, the physiological workload involved in shoulder/elbow-mode carrying was investigated, especially focusing on the effects of load weight and inclination. To measure heart rate and oxygen uptake while carrying on the shoulder/elbow, a laboratory experiment was conducted and safety guidelines for such tasks were proposed, based on the experimental results. Four healthy male subjects performed shoulder/elbow-mode carrying, weight between 20 and 24 kg: (1) on inclination of 10o, (2) 20o and (3) 30o. The results showed that inclination involved an increased physiological burden, and that a load of 24 kg entailed a significantly higher physiological cost than carrying a load of 20 kg. Although shoulder/elbow-mode carrying has some advantages, the worker should be advised to carry a load of less than 20 kg, to avoid a high physiological load. During shoulder/elbow-mode carrying, it is also recommended that a person prepare more training in order to have muscular strength.

  20. Noninvasive optical quantification of absolute blood flow, blood oxygenation, and oxygen consumption rate in exercising skeletal muscle

    Science.gov (United States)

    Gurley, Katelyn; Shang, Yu; Yu, Guoqiang

    2012-07-01

    This study investigates a method using novel hybrid diffuse optical spectroscopies [near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS)] to obtain continuous, noninvasive measurement of absolute blood flow (BF), blood oxygenation, and oxygen consumption rate (\\Vdot O2) in exercising skeletal muscle. Healthy subjects (n=9) performed a handgrip exercise to increase BF and \\Vdot O2 in forearm flexor muscles, while a hybrid optical probe on the skin surface directly monitored oxy-, deoxy-, and total hemoglobin concentrations ([HbO2], [Hb], and THC), tissue oxygen saturation (StO2), relative BF (rBF), and relative oxygen consumption rate (r\\Vdot O2). The rBF and r\\Vdot O2 signals were calibrated with absolute baseline BF and \\Vdot O2 obtained through venous and arterial occlusions, respectively. Known problems with muscle-fiber motion artifacts in optical measurements during exercise were mitigated using a novel gating algorithm that determined muscle contraction status based on control signals from a dynamometer. Results were consistent with previous findings in the literature. This study supports the application of NIRS/DCS technology to quantitatively evaluate hemodynamic and metabolic parameters in exercising skeletal muscle and holds promise for improving diagnosis and treatment evaluation for patients suffering from diseases affecting skeletal muscle and advancing fundamental understanding of muscle and exercise physiology.

  1. Reflex bradycardia does not influence oxygen consumption during hypoxia in the European eel (Anguilla anguilla)

    DEFF Research Database (Denmark)

    Iversen, Nina Kerting; McKenzie, David; Malte, H.

    2010-01-01

    the bradycardia on oxygen consumption (MO2), standard metabolic rate (SMR) and the critical oxygen partial pressure for regulation of SMR in hypoxia (Pcrit) in European eels Anguilla anguilla (mean ± SEM mass 528 ± 36 g; n = 14). Eels were instrumented with a Transonic flow probe around the ventral aorta......Most teleost fish reduce heart rate when exposed to acute hypoxia. This hypoxic bradycardia has been characterised for many fish species, but it remains uncertain whether this reflex contributes to the maintenance of oxygen uptake in hypoxia. Here we describe the effects of inhibiting...

  2. Rate of oxygen consumption of hamster melanoma cells as a factor influencing their radioresistance

    International Nuclear Information System (INIS)

    Pajak, S.; Subczynski, W.; Panz, T.; Lukiewicz, S.

    1980-01-01

    It has been reported in recent years that the level of radiosensitivity of neoplasmic cells in vivo and of sphaeroids in vitro can be modified by controlling their rate of oxygen consumption. Thus, an attempt was made to compare this rate in the case of the melanotic and amelanotic lines of Bomirski hamster melanoma in vitro, as it is known that these two lines distinctly differ in their reactivity to ionizing radiations. The measurements carried out by the use of a new ESR method revealed that pigmented and pigmentless cells consume oxygen at significantly different rates. This means that oxygen utilization may contribute to the overall level of radioresistance of melanoma cells. (author)

  3. A novel approach to the assess biotic oxygen consumption in marine sediment communities

    Science.gov (United States)

    Baranov, Victor; Queiros, Ana; Widdicombe, Stephen; Stephens, Nick; Lessin, Gennadi; Krause, Stefan; Lewandowski, Joerg

    2016-04-01

    Bioturbation , the mixing of the sediment matrix by burrowing animals impacts sediment metabolism, including respiration through redistribution of particulate organics, changes in bacterial biota diversity and acitivity, as well as via burrowing fauna's own metabolism. Bioturbation, reflecting faunal activity, is also a proxy for the general sedimentary ecosystem health, and can be impacted by many of emerging marine environmental issues such as ocean acidification, warming and the occurrence of heat waves. Sedimentary oxygen consumption is often taken as a proxy for the activity of bioturbating fauna, but determining baselines can be difficult because of the confounding effects of other fauna and microbes present in sediments, as well as irnorganic processes that consume oxygen. Limitations therefore exist in current methodologies, and numerous confounding factors are hampering progress in this area. Here, we present novel method for the assessment of sediment respiration which is expected to be affected only by the biogenic oxygen consumption (namely aerobic respiration). As long as tracer reduction "immune" to inorganic oxygen consumption, so that measurements using this method can be used, alongside traditional methods, to decouple biological respiration from inorganic oxygen consumption reactions. The tracer is easily detectable, non-toxic and can be applied in systems with constant oxygen supply. The latter allow for incubation without the need to to work with unsealed experimental units, bringing procedural advantage over traditional methods. Consequently assessed bioturbating fauna is not exposed to hypoxia and additional stress. Here, we had applied system for the first time to investigate impacts of a common North-Atlantic bioturbator, the brittle star Amphiura filiformis, - on respiration of marine sediments. Two series of experiments were conducted with animals and sediment collected from Cawsand Bay, Plymouth, UK Preliminary results show that tracer

  4. Contribution of Respiratory Muscle Oxygen Consumption to Breathing Limitation and Cyspnea

    Directory of Open Access Journals (Sweden)

    Pere Casan

    1997-01-01

    Full Text Available During exercise, the sustainable activity of large muscle groups is limited by oxygen delivery. The purpose of this study was to see whether the oxygen consumption of the respiratory muscles reaches a similar critical value under maximal resistive loading and hyperventilation. A secondary objective was to see whether dyspnea (estimated discomfort experienced with breathing using the Borg 0-10 scale and the oxygen consumption of the respiratory muscles are closely related across conditions. This would be expected if intramuscular sensory nerve fibres stimulated as a consequence of metabolic events contributed to this sensation. In six normal subjects the respiratory muscles were progressively activated by the addition of incremental inspiratory resistive loads to a maximum of 300 cm H20×s/L (SD=66.4, and incremental dead space to a maximum of 2638 mL (SD=452, associated with an increase in ventilation to 75.1 L/min (SD=29.79. Each increment was maintained for 5 mins to allow the measurement of oxygen uptake in a steady state. During resistive loading total oxygen consumption increased from 239 mL/min (SD=38.2 to 299 mL/min (SD=52.3 and dyspnea increased to "very severe" (Borg scale 7.5, SD=1.55. During dead space loading total oxygen consumption increased from 270 mL/min (SD=20.2 to 426 mL/min (SD=81.9 and dyspnea increased to "very severe" (7.1, SD=0.66. Oxygen cost of inspiratory muscle power was 25 mL/watt (95% confidence limits 16.7 to 34.3 with dead space loading and 91 mL/watt (95% confidence limits 54 to 128 with resistive loading. Oxygen consumption did not reach a critical common value in the two types of loading, 60 mL/min (SD 22.3 during maximal resistive loading and 156 mL/min (SD 82.4 during maximal dead space loading (P<0.05. Physiological factors limiting the respiratory muscles are not uniquely related to oxygen consumption and appear to be expressed through the activation of sensory structures, perceptually manifested as

  5. Mechanisms controlling the oxygen consumption in experimentally induced hypochloremic alkalosis in calves.

    Science.gov (United States)

    Cambier, Carole; Clerbaux, Thierry; Amory, Hélène; Detry, Bruno; Florquin, Sandra; Marville, Vincent; Frans, Albert; Gustin, Pascal

    2002-01-01

    The study was carried out on healthy Friesian calves (n = 10) aged between 10 and 30 days. Hypochloremia and alkalosis were induced by intravenous administration of furosemide and isotonic sodium bicarbonate. The venous and arterial blood samples were collected repeatedly. 2,3-diphosphoglycerate (2,3-DPG), hemoglobin and plasmatic chloride concentrations were determined. The red blood cell chloride concentration was also calculated. pH, PCO2 and PO2 were measured in arterial and mixed venous blood. The oxygen equilibrium curve (OEC) was measured in standard conditions. The correspondence of the OEC to the arterial and mixed venous compartments was calculated, taking blood temperature, pH and PCO2 values into account. The oxygen exchange fraction (OEF%), corresponding to the degree of blood desaturation between the arterial and mixed venous compartments and the amount of oxygen released at the tissue level by 100 mL of blood (OEF Vol%) were calculated from the arterial and mixed venous OEC, combined with PO2 and hemoglobin concentration. Oxygen delivery (DO2) was calculated using the arterial oxygen content, the cardiac output measured by thermodilution, and the body weight of the animal. The oxygen consumption (VO2) was derived from the cardiac output, OEF Vol% and body weight values. Despite the plasma hypochloremia, the erythrocyte chloride concentration was not influenced by furosemide and sodium bicarbonate infusion. Due to the alkalosis-induced increase in the 2,3-DPG, the standard OEC was shifted to the right, allowing oxygen to dissociate from hemoglobin more rapidly. These changes opposed the increased affinity of hemoglobin for oxygen induced by alkalosis. Moreover, respiratory acidosis, hemoconcentration, and the slight decrease in the partial oxygen pressure in mixed venous blood (Pvo2) tended to improve the OEF Vol% and maintain the oxygen consumption in a physiological range while the cardiac output, and the oxygen delivery were significantly decreased

  6. Oxygen Consumption Constrains Food Intake in Fish Fed Diets Varying in Essential Amino Acid Composition

    NARCIS (Netherlands)

    Subramanian, S.; Geurden, I.; Figueiredo-Silva, A.C.; Nusantoro, S.; Kaushik, S.J.; Verreth, J.A.J.; Schrama, J.W.

    2013-01-01

    Compromisation of food intake when confronted with diets deficient in essential amino acids is a common response of fish and other animals, but the underlying physiological factors are poorly understood. We hypothesize that oxygen consumption of fish is a possible physiological factor constraining

  7. Measurement of oxygen consumption with the Cosmed K2: a comparative study

    NARCIS (Netherlands)

    Forkink, A.; Frings-Dresen, M. H.

    1994-01-01

    An instrument that accurately measures oxygen consumption (VO2) during field performance is valuable for investigations of physiological workload. Cosmed (Rome, Italy) has introduced such an instrument, the Cosmed K2. In this study the Cosmed K2 was compared with the Oxyconbeta (Jaeger, Breda, The

  8. Effects of cadmium chloride on oxygen consumption and gill morphology of Indian flying barb, Esomus danricus.

    Science.gov (United States)

    Das, Suchismita; Gupta, Abhik

    2012-11-01

    Effects of three sub lethal concentrations of cadmium chloride (0.636, 0.063 and 0.006 mg l(-1)) on oxygen consumption and gill morphology in Indian flying barb, Esomus danricus (Hamilton-Buchanan), a teleost fish, were studied. When compared to control, 0.636 mg l(-1) of cadmium chloride after 7,14, 21 and 28 day exposure showed a significant decline in rates of oxygen consumption at 32.98, 28.40, 23.88 and 21.69 ml hr(1) 100 g(-1) of tissue, respectively; while, 0.063 mg l(-1) of cadmium chloride for the same exposure durations showed a significant decline in rates of oxygen consumption at 34.28, 29.30, 28.05 and 26.47 ml hr(1)100 g(-1) of tissue, respectively. However, significant decline in the rate of oxygen consumption at 0.006 mg l(-1) of cadmium chloride could be observed from 21st day of exposure. Gill tissue showed various histopathological changes including epithelial lifting, hyperplasia, mucous secretion, marked leucocyte infiltration in the epithelium after 28 days of cadmium chloride exposure.

  9. High intensity aerobic interval training improves peak oxygen consumption in patients with metabolic syndrome: CAT

    Directory of Open Access Journals (Sweden)

    Alexis Espinoza Salinas

    2014-06-01

    Full Text Available Introduction A number of cardiovascular risk factors characterizes the metabolic syndrome: insulin resistance (IR, low HDL cholesterol and high triglycerides. The aforementioned risk factors lead to elevated levels of abdominal adipose tissue, resulting in oxygen consumption deficiency. Purpose To verify the validity and applicability of using high intensity interval training (HIIT in subjects with metabolic syndrome and to answer the following question: Can HIIT improve peak oxygen consumption? Method The systematic review "Effects of aerobic interval training on exercise capacity and metabolic risk factors in individuals with cardiometabolic disorders" was analyzed. Results Data suggests high intensity aerobic interval training increases peak oxygen consumption by a standardized mean difference of 3.60 mL/kg-1/min-1 (95% confidence interval, 0.28-4.91. Conclusion In spite of the methodological shortcomings of the primary studies included in the systematic review, we reasonably conclude that implementation of high intensity aerobic interval training in subjects with metabolic syndrome, leads to increases in peak oxygen consumption.

  10. Using carbon emissions, oxygen consumption, and retained energy to calculate dietary ME intake by beef steers

    Science.gov (United States)

    Eight cross-bred beef steers (initial BW = 241 ± 4.10 kg) were used in a 77-d feeding experiment to determine if ME intake can be determined from carbon emissions, oxygen consumption, and energy retention estimates. Steers were housed in a pen equipped with individual feed bunks and animal access w...

  11. Diffusion Limitation and Hyperoxic Enhancement of Oxygen Consumption in Zooxanthellate Sea Anemones, Zoanthids, and Corals.

    Science.gov (United States)

    Shick, J M

    1990-08-01

    Depending on their size and morphology, anthozoan polyps and colonies may be diffusion-limited in their oxygen consumption, even under well-stirred, air-saturated conditions. This is indicated by an enhancement of oxygen consumption under steady-state hyperoxic conditions that simulate the levels of O2 produced photosynthetically by zooxanthellae in the hosts' tissues. Such hyperoxia in the tissues of zooxanthellate species negates the effect of the diffusive boundary layer, and increases the rate of oxygen consumption; thus, in many cases, the rate of respiration measured under normoxia in the dark may not be representative of the rate during the day when the zooxanthellae are photosynthesizing and when the supply of oxygen for respiration is in the tissues themselves, not from the environment. These results have implications in respirometric methodology and in calculating the rate of gross photosynthesis in energetic studies. The activity of cytochrome c oxidase is higher in aposymbiotic than in zooxanthellate specimens of the sea anemone Aiptasia pulchella, and this may indicate a compensation for the relative hypoxia in the tissues of the former, enhancing the delivery of oxygen to the mitochondria from the environment.

  12. Effect of training in minimalist footwear on oxygen consumption during walking and running.

    Science.gov (United States)

    Bellar, D; Judge, L W

    2015-06-01

    The present study sought to examine the effect of 5 weeks of training with minimalist footwear on oxygen consumption during walking and running. Thirteen college-aged students (male n = 7, female n = 6, age: 21.7±1.4 years, height: 168.9±8.8 cm, weight: 70.4±15.8 kg, VO2max: 46.6±6.6 ml·kg(-1)·min(-1)) participated in the present investigation. The participants did not have experience with minimalist footwear. Participants underwent metabolic testing during walking (5.6 km·hr(-1)), light running (7.2 km·hr(-1)), and moderate running (9.6 km·hr(-1)). The participants completed this assessment barefoot, in running shoes, and in minimalist footwear in a randomized order. The participants underwent 5 weeks of training with the minimalist footwear. Afterwards, participants repeated the metabolic testing. Data was analyzed via repeated measures ANOVA. The analysis revealed a significant (F4,32= 7.576, [Formula: see text]=0.408, p ≤ 0.001) interaction effect (time × treatment × speed). During the initial assessment, the minimalist footwear condition resulted in greater oxygen consumption at 9.6 km·hr(-1) (p ≤ 0.05) compared to the barefoot condition, while the running shoe condition resulted in greater oxygen consumption than both the barefoot and minimalist condition at 7.2 and 9.6 km·hr(-1). At post-testing the minimalist footwear was not different at any speed compared to the barefoot condition (p> 0.12). This study suggests that initially minimalist footwear results in greater oxygen consumption than running barefoot, however; with utilization the oxygen consumption becomes similar.

  13. Crouch severity is a poor predictor of elevated oxygen consumption in cerebral palsy.

    Science.gov (United States)

    Steele, Katherine M; Shuman, Benjamin R; Schwartz, Michael H

    2017-07-26

    Children with cerebral palsy (CP) expend more energy to walk compared to typically-developing peers. One of the most prevalent gait patterns among children with CP, crouch gait, is often singled out as especially exhausting. The dynamics of crouch gait increase external flexion moments and the demand on extensor muscles. This elevated demand is thought to dramatically increase energy expenditure. However, the impact of crouch severity on energy expenditure has not been investigated among children with CP. We evaluated oxygen consumption and gait kinematics for 573 children with bilateral CP. The average net nondimensional oxygen consumption during gait of the children with CP (0.18±0.06) was 2.9 times that of speed-matched typically-developing peers. Crouch severity was only modestly related to oxygen consumption, with measures of knee flexion angle during gait explaining only 5-20% of the variability in oxygen consumption. While knee moment and muscle activity were moderately to strongly correlated with crouch severity (r 2 =0.13-0.73), these variables were only weakly correlated with oxygen consumption (r 2 =0.02-0.04). Thus, although the dynamics of crouch gait increased muscle demand, these effects did not directly result in elevated energy expenditure. In clinical gait analysis, assumptions about an individual's energy expenditure should not be based upon kinematics or kinetics alone. Identifying patient-specific factors that contribute to increased energy expenditure may provide new pathways to improve gait for children with CP. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Fractional Consumption of Liquid Hydrogen and Liquid Oxygen During the Space Shuttle Program

    Science.gov (United States)

    Partridge, Jonathan K.

    2011-01-01

    The Space Shuttle uses the propellants, liquid hydrogen and liquid oxygen, to meet part of the propulsion requirements from ground to orbit. The Kennedy Space Center procured over 25 million kilograms of liquid hydrogen and over 250 million kilograms of liquid oxygen during the 3D-year Space Shuttle Program. Because of the cryogenic nature of the propellants, approximately 55% of the total purchased liquid hydrogen and 30% of the total purchased liquid oxygen were used in the Space Shuttle Main Engines. The balance of the propellants were vaporized during operations for various purposes. This paper dissects the total consumption of liqUid hydrogen and liqUid oxygen and determines the fraction attributable to each of the various processing and launch operations that occurred during the entire Space Shuttle Program at the Kennedy Space Center.

  15. Factors determining the oxygen consumption rate (VO2) on-kinetics in skeletal muscles.

    OpenAIRE

    Korzeniewski, Bernard; Zoladz, Jerzy A

    2004-01-01

    Using a computer model of oxidative phosphorylation developed previously [Korzeniewski and Mazat (1996) Biochem. J. 319, 143-148; Korzeniewski and Zoladz (2001) Biophys. Chem. 92, 17-34], we analyse the effect of several factors on the oxygen-uptake kinetics, especially on the oxygen consumption rate (VO2) and half-transition time t(1/2), at the onset of exercise in skeletal muscles. Computer simulations demonstrate that an increase in the total creatine pool [PCr+/-Cr] (where Cr stands for c...

  16. Positron tomography investigation in humans of the local coupling among CBF, oxygen consumption and glucose utilization

    Energy Technology Data Exchange (ETDEWEB)

    Baron, J C; Rougemont, D; Soussaline, F; Crouzel, C; Bousser, M G; Comar, D

    1983-06-01

    Positron tomography investigation of the local coupling among cerebral blood flow (CBF), oxygen consumption (CMRO/sub 2/) and glucose utilization (CMRGlc) was performed in 5 controls and 6 ischemic stroke patients, using oxygen 15 inhalation technique immediately followed by I.V. injection of /sup 18/F-Fluoro-Desoxyglucose (/sup 18/FDG). The normal couple among all 3 variables was demonstrated; but on the other hand significant disruption of either or both the CBF-CMRGlc and the CMRO/sub 2/-CMRGlc couples was found in all 6 stroke patients. Comments on these new findings were made.

  17. Oxygen delivery and consumption during on-bypass cabg in htea and central analgesia

    Directory of Open Access Journals (Sweden)

    Віталій Олексійович Собокарь

    2015-04-01

    Full Text Available Objective. Despite some advantages, the use of high thoracic epidural anesthesia (HTEA during on-bypass cardiac surgery may be discouraged by fear of adverse hemodynamic effects and associated disturbances of oxygen delivery.Aim. To compare oxygen delivery and consumption during on-bypass coronary artery bypass grafting in settings of HTEA and central analgesia (CA.Methods. 132 patients were assigned into two groups – study group (n=85, where the surgery was performed under HTEA and control group (n=47 - where the surgery was carried out under CA. Using data of transesophageal cardiac ultrasound and blood oximetry blood oxygen delivery (DO2, oxygen consumption (VO2, oxygen extraction coefficient (CEO2 were calculated at four stages of the surgery: after induction, sternotomy, cardiopulmonary bypass and at the end of the surgery.Results. In the initial stages of the surgery DO2 and VO2 were reduced relative to reference values with a tendency to increase in the course of the operation and achievement of the normal or supernormal level (VO2, study group in the final stage. The decrease was due to moderate hypodynamic circulation and hemodilution. After sternotomy DO2 in the study group was higher than that of the control: 356 (279; 458 vs 317±89 ml·min-1·m-2, (р=0,021. After cardiopulmonary bypass oxygen saturation of venous blood (SatvO2, in the study group was 71 ± 9 % compared with 68 ± 10 % in the control group. At the end of the surgery SatvO2 in the study group was 71 (66; 75 vs 59 (53; 70 % in the control (р = 0,005 and oxygen tension of venous blood (РvО2 was correspondingly 39 ± 6 and 33 (30; 38 mm Hg (р = 0,027. Despite the decrease in DO2 and VO2, oxygen extraction indices - CEO2, pvO2, SatvO2, and remained within the reference range, except that of the control group at the end of the surgery. Furthermore, at no stage lactate rise or acid-base deviations was observed in the both groups.Conclusions. In patients operated

  18. In situ measurement of the rate of oxygen consumption by the Callovo-Oxfordian argillaceous rock

    International Nuclear Information System (INIS)

    Vinsot, A.; Lundy, M.; Claret, F.; Wechner, S.

    2012-01-01

    Document available in extended abstract form only. The ventilation of excavated drifts in the Callovo-Oxfordian argillaceous rock induces its exposure to air. The oxygen from air reacts with several reduced mineral species from the rock. It may also react with organic species existing in the rock. The effects of these reactions on the rock mineralogy were observed in the first meters of many boreholes drilled in the Andra's Underground Research Laboratory (URL) drifts at 490 m deep. They generate mainly sulfated and ferric secondary phases. The consequences of these reactions on the evolution of a radioactive waste disposal in such a rock are two folds. First, they will contribute to oxygen consumption and the generation of an anoxic atmosphere in the drifts and vaults after their closure. In addition, they will influence the composition of the water which will later on fill the drifts and vaults. These phenomena are taken into account in the modeling of disposal evolutions at various times and space scales. The main remaining uncertainties regarding these phenomena concern: i) the identification of all the species involved in the oxygen reduction; ii) the reaction kinetics; and iii) the extension of the oxidized zone around the drifts and vaults. The aim of the 'POX experiment' is to reduce these uncertainties. This experiment includes a test dedicated to the quantitative study of oxygen consumption in the Callovo-Oxfordian argillaceous rock. This test was implemented in 2009 in the Andra's URL. After an initial phase during which the rock natural gases and pore water at the test location were observed, the first oxygen injection was performed in July 2011. The experimental concept is based on gas circulation in a borehole. It consists of a 15 m-long and 76 mm-diameter ascending borehole, from which the last 5 m constitute the test interval. The rock surface in the test interval is close to 1 m 2 . The last 6 m of the borehole were cored with argon as a drilling

  19. Relation of Mitochondrial Oxygen Consumption in Peripheral Blood Mononuclear Cells to Vascular Function in Type 2 Diabetes Mellitus

    Science.gov (United States)

    Hartman, Mor-Li; Shirihai, Orian S.; Holbrook, Monika; Xu, Guoquan; Kocherla, Marsha; Shah, Akash; Fetterman, Jessica L.; Kluge, Matthew A.; Frame, Alissa A.; Hamburg, Naomi M.; Vita, Joseph A.

    2014-01-01

    Recent studies have shown mitochondrial dysfunction and increased production of reactive oxygen species in peripheral blood mononuclear cells (PBMC’s) and endothelial cells from patients with diabetes mellitus. Mitochondria oxygen consumption is coupled to ATP production and also occurs in an uncoupled fashion during formation of reactive oxygen species by components of the electron transport chain and other enzymatic sites. We therefore hypothesized that diabetes would be associated with higher total and uncoupled oxygen consumption in PBMC’s that would correlate with endothelial dysfunction. We developed a method to measure oxygen consumption in freshly isolated PBMC’s and applied it to 26 patients with type 2 diabetes mellitus and 28 non-diabetic controls. Basal (192±47 vs. 161±44 pMoles/min, P=0.01), uncoupled (64±16 vs. 53±16 pMoles/min, P=0.007), and maximal (795±87 vs. 715±128 pMoles/min, P=0.01) oxygen consumption rates were higher in diabetic patients compared to controls. There were no significant correlations between oxygen consumption rates and endothelium-dependent flow-mediated dilation measured by vascular ultrasound. Non-endothelium-dependent nitroglycerin-mediated dilation was lower in diabetics (10.1±6.6 vs. 15.8±4.8%, P=0.03) and correlated with maximal oxygen consumption (R= −0.64, P=0.001). In summary, we found that diabetes mellitus is associated with a pattern of mitochondrial oxygen consumption consistent with higher production of reactive oxygen species. The correlation between oxygen consumption and nitroglycerin-mediated dilation may suggest a link between mitochondrial dysfunction and vascular smooth muscle cell dysfunction that merits further study. Finally, the described method may have utility for assessment of mitochondrial function in larger scale observational and interventional studies in humans. PMID:24558030

  20. Effect of remifentanil on mitochondrial oxygen consumption of cultured human hepatocytes.

    Directory of Open Access Journals (Sweden)

    Siamak Djafarzadeh

    Full Text Available During sepsis, liver dysfunction is common, and failure of mitochondria to effectively couple oxygen consumption with energy production has been described. In addition to sepsis, pharmacological agents used to treat septic patients may contribute to mitochondrial dysfunction. This study addressed the hypothesis that remifentanil interacts with hepatic mitochondrial oxygen consumption. The human hepatoma cell line HepG2 and their isolated mitochondria were exposed to remifentanil, with or without further exposure to tumor necrosis factor-α (TNF-α. Mitochondrial oxygen consumption was measured by high-resolution respirometry, Caspase-3 protein levels by Western blotting, and cytokine levels by ELISA. Inhibitory κBα (IκBα phosphorylation, measurement of the cellular ATP content and mitochondrial membrane potential in intact cells were analysed using commercial ELISA kits. Maximal cellular respiration increased after one hour of incubation with remifentanil, and phosphorylation of IκBα occurred, denoting stimulation of nuclear factor κB (NF-κB. The effect on cellular respiration was not present at 2, 4, 8 or 16 hours of incubation. Remifentanil increased the isolated mitochondrial respiratory control ratio of complex-I-dependent respiration without interfering with maximal respiration. Preincubation with the opioid receptor antagonist naloxone prevented a remifentanil-induced increase in cellular respiration. Remifentanil at 10× higher concentrations than therapeutic reduced mitochondrial membrane potential and ATP content without uncoupling oxygen consumption and basal respiration levels. TNF-α exposure reduced respiration of complex-I, -II and -IV, an effect which was prevented by prior remifentanil incubation. Furthermore, prior remifentanil incubation prevented TNF-α-induced IL-6 release of HepG2 cells, and attenuated fragmentation of pro-caspase-3 into cleaved active caspase 3 (an early marker of apoptosis. Our data suggest that

  1. Acute effects of Cu on oxygen consumption and 96 hr-LC 50 values ...

    African Journals Online (AJOL)

    The median lethal copper (Cu) concentration (96 hr-LC50) values for acute Cu toxicity for Tilapia sparrmanii (live mass: 30 ± 8g) in Mooi River hard water of dolomitic origin at 20° C, pH 7.9, was 68.1 µmol l–1. At this 96 hr-LC50 value the specific oxygen consumption rate (∉ O2) decreased by 44.2 (± 2.1) % from a ...

  2. The effect of external dummy transmitters on oxygen consumption and performance of swimming Atlantic cod

    DEFF Research Database (Denmark)

    Steinhausen, M.F.; Andersen, Niels Gerner; Steffensen, J.F.

    2006-01-01

    Decreased critical swimming speed and increased oxygen consumption (Mo-2) was found for externally tagged Atlantic cod Gadus morhua swimming at a high speed of 0 center dot 9 body length (total length, L-Gamma) s(-1). No difference was found in the standard metabolic rate, indicating...... that the higher Mo-2 for tagged cod was due to drag force rather than increased costs to keep buoyancy. (c) 2006 The Authors Journal compilation (c) 2006 The Fisheries Society of the British Isles....

  3. Effect of aeration interval on oxygen consumption and GHG emission during pig manure composting.

    Science.gov (United States)

    Zeng, Jianfei; Yin, Hongjie; Shen, Xiuli; Liu, Ning; Ge, Jinyi; Han, Lujia; Huang, Guangqun

    2018-02-01

    To verify the optimal aeration interval for oxygen supply and consumption and investigate the effect of aeration interval on GHG emission, reactor-scale composting was conducted with different aeration intervals (0, 10, 30 and 50 min). Although O 2 was sufficiently supplied during aeration period, it could be consumed to  0.902), suggesting that lengthening the duration of aeration interval to some extent could effectively reduce GHG emission. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. The effect of additional carbohydrate supplements for 7 days after prolonged interval exercise on exercise performance and energy metabolism during submaximal exercise in team-sports athletes.

    Science.gov (United States)

    Park, Hun-Young; Kim, Jisu; Park, Miyoung; Chung, Nana; Lim, Kiwon

    2018-03-30

    The purpose of our study was to determine the effectiveness of carbohydrate loading by additional carbohydrate supplements for 7 days after prolonged interval exercise on exercise performance and energy metabolism during submaximal exercise in team-sports athletes. Twenty male team-sports athletes (14 soccer and 6 rugby players) volunteered to participate in the study and were equally divided into the experimental group (EXP, n=10) performing additional carbohydrate supplementation for 7 days after prolonged interval exercise until blood glucose level reaches 50 mg/dL or less and the control group (CON, n=10). Then, maximal oxygen consumption (VO2max) and minute ventilation (VE), oxygen consumption (VO2), carbon dioxide excretion (VCO2), respiratory exchange ratio (RER), blood glucose level, and blood lactate level were measured in all team-sports players during submaximal exercise corresponding to 70% VO2max before and after intervention. There was no significant interaction in all parameters, but team-sports players in the EXP presented more improved VO2max (CON vs EXP = vs 5.3% vs 6.3%), VE (CON vs EXP = vs 3.8% vs 6.6%), VO2 (CON vs EXP = vs 8.5% vs 9.9%), VCO2 (CON vs EXP = vs 2.8% vs 4.0%), blood glucose level (CON vs EXP = vs -12.9% vs -7.6%), and blood lactate level (CON vs EXP = -18.2% vs -25%) compared to those in the CON. These findings showed that additional carbohydrate supplementation conducted in our study is not effective in exercise performance and energy metabolism during submaximal exercise. ©2018 The Korean Society for Exercise Nutrition.

  5. The effect of additional carbohydrate supplements for 7 days after prolonged interval exercise on exercise performance and energy metabolism during submaximal exercise in team-sports athletes

    Science.gov (United States)

    Park, Hun-Young; Kim, Jisu; Park, Miyoung; Chung, Nana; Lim, Kiwon

    2018-01-01

    [Purpose] The purpose of our study was to determine the effectiveness of carbohydrate loading by additional carbohydrate supplements for 7 days after prolonged interval exercise on exercise performance and energy metabolism during submaximal exercise in team-sports athletes. [Methods] Twenty male team-sports athletes (14 soccer and 6 rugby players) volunteered to participate in the study and were equally divided into the experimental group (EXP, n=10) performing additional carbohydrate supplementation for 7 days after prolonged interval exercise until blood glucose level reaches 50 mg/dL or less and the control group (CON, n=10). Then, maximal oxygen consumption (VO2max) and minute ventilation (VE), oxygen consumption (VO2), carbon dioxide excretion (VCO2), respiratory exchange ratio (RER), blood glucose level, and blood lactate level were measured in all team-sports players during submaximal exercise corresponding to 70% VO2max before and after intervention. [Results] There was no significant interaction in all parameters, but team-sports players in the EXP presented more improved VO2max (CON vs EXP = vs 5.3% vs 6.3%), VE (CON vs EXP = vs 3.8% vs 6.6%), VO2 (CON vs EXP = vs 8.5% vs 9.9%), VCO2 (CON vs EXP = vs 2.8% vs 4.0%), blood glucose level (CON vs EXP = vs -12.9% vs -7.6%), and blood lactate level (CON vs EXP = -18.2% vs -25%) compared to those in the CON. [Conclusion] These findings showed that additional carbohydrate supplementation conducted in our study is not effective in exercise performance and energy metabolism during submaximal exercise. PMID:29673243

  6. Continuous Real-time Viability Assessment of Kidneys Based on Oxygen Consumption

    Science.gov (United States)

    Weegman, B.P.; Kirchner, V.A.; Scott, W.E.; Avgoustiniatos, E.S.; Suszynski, T.M.; Ferrer-Fabrega, J.; Rizzari, M.D.; Kidder, L.S.; Kandaswamy, R.; Sutherland, D.E.R.; Papas, K.K.

    2010-01-01

    Background Current ex vivo quality assessment of donor kidneys is limited to vascular resistance measurements and histological analysis. New techniques for the assessment of organ quality before transplantation may further improve clinical outcomes while expanding the depleted deceased-donor pool. We propose the measurement of whole organ oxygen consumption rate (WOOCR) as a method to assess the quality of kidneys in real time before transplantation. Methods Five porcine kidneys were procured using a donation after cardiac death (DCD) model. The renal artery and renal vein were cannulated and the kidney connected to a custom-made hypothermic machine perfusion (HMP) system equipped with an inline oxygenator and fiber-optic oxygen sensors. Kidneys were perfused at 8°C, and the perfusion parameters and partial oxygen pressures (pO2) were measured to calculate WOOCR. Results Without an inline oxygenator, the pO2 of the perfusion solution at the arterial inlet and venous outlet diminished to near 0 within minutes. However, once adequate oxygenation was provided, a significant pO2 difference was observed and used to calculate the WOOCR. The WOOCR was consistently measured from presumably healthy kidneys, and results suggest that it can be used to differentiate between healthy and purposely damaged organs. Conclusions Custom-made HMP systems equipped with an oxygenator and inline oxygen sensors can be applied for WOOCR measurements. We suggest that WOOCR is a promising approach for the real-time quality assessment of kidneys and other organs during preservation before transplantation. PMID:20692397

  7. Metabolic cold adaptation of polar fish based on measurements of aerobic oxygen consumption: fact or artefact? Artefact!

    DEFF Research Database (Denmark)

    Steffensen, John Fleng

    2002-01-01

    Whether metabolic cold adaptation in polar fish, based on measurements of aerobic standard metabolic rate, is a fact or an artefact has been a dispute since Holeton asked the question in 1974. So far polar fish had been considered to be metabolically cold adapted because they were reported to have...... a considerably elevated resting oxygen consumption, or standard metabolic rate, compared with oxygen consumption values of tropical or temperate fish extrapolated to similar low polar temperatures. Recent experiments on arctic and Antarctic fish, however, do not show elevated resting aerobic oxygen consumption...

  8. Effect of suspension systems on the physiological and psychological responses to sub-maximal biking on simulated smoothand bumpy tracks.

    Science.gov (United States)

    Titlestad, John; Fairlie-Clarke, Tony; Whittaker, Arthur; Davie, Mark; Watt, Ian; Grant, Stanley

    2006-02-01

    The aim of this study was to compare the physiological and psychological responses of cyclists riding on a hard tail bicycle and on a full suspension bicycle. Twenty males participated in two series of tests. A test rig held the front axle of the bicycle steady while the rear wheel rotated against a heavy roller with bumps (or no bumps) on its surface. In the first series of tests, eight participants (age 19-27 years, body mass 65-82 kg) were tested on both the full suspension and hard tail bicycles with and without bumps fitted to the roller. The second series of test repeated the bump tests with a further six participants (age 22-31 years, body mass 74-94 kg) and also involved an investigation of familiarization effects with the final six participants (age 21-30 years, body mass 64-80 kg). Heart rate, oxygen consumption (VO(2)), rating of perceived exertion (RPE) and comfort were recorded during 10 min sub-maximal tests. Combined data for the bumps tests show that the full suspension bicycle was significantly different (P < 0.001) from the hard tail bicycle on all four measures. Oxygen consumption, heart rate and RPE were lower on average by 8.7 (s = 3.6) ml . kg(-1) . min(-1), 32.1 (s = 12.1) beats . min(-1) and 2.6 (s = 2.0) units, respectively. Comfort scores were higher (better) on average by 1.9 (s = 0.8) units. For the no bumps tests, the only statistically significant difference (P = 0.008) was in VO(2), which was lower for the hard tail bicycle by 2.2 (s = 1.7) ml . kg(-1) . min(-1). The results indicate that the full suspension bicycle provides a physiological and psychological advantage over the hard tail bicycle during simulated sub-maximal exercise on bumps.

  9. Athletes and Sedentary Individuals: An Intergroup Comparison Utilizing a Pulmonary Function Ratio Obtained During Submaximal Exercise.

    Science.gov (United States)

    Maud, Peter J.

    A pulmonary function ratio describing oxygen extraction from alveolar ventilation was used for an intergroup comparison between three groups of athletes (rugby, basketball, and football players) and one group of sedentary subjects during steady-state submaximal exercise. The ratio and its component parts are determined from only three gas…

  10. Atrial natriuretic peptide regulates lipid mobilization and oxygen consumption in human adipocytes by activating AMPK

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Sandra C. [Translational Sciences - Translational Medicine, Novartis Institutes for Biomedical Research, Inc., 220 Massachusetts Avenue, Cambridge, MA 02139 (United States); Chau, Mary D.L.; Yang, Qing [Cardiovascular and Metabolism Disease Area, Novartis Institutes for Biomedical Research, Inc., 100 Technology Square, Cambridge, MA 02139 (United States); Gauthier, Marie-Soleil [Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA 02140 (United States); Clairmont, Kevin B.; Wu, Zhidan; Gromada, Jesper [Cardiovascular and Metabolism Disease Area, Novartis Institutes for Biomedical Research, Inc., 100 Technology Square, Cambridge, MA 02139 (United States); Dole, William P., E-mail: bill.dole@novartis.com [Translational Sciences - Translational Medicine, Novartis Institutes for Biomedical Research, Inc., 220 Massachusetts Avenue, Cambridge, MA 02139 (United States)

    2011-07-08

    Highlights: {yields} Treatment of differentiated human adipocytes with atrial natriuretic peptide (ANP) increased lipolysis and oxygen consumption by activating AMP-activated protein kinase (AMPK). {yields} ANP stimulated lipid mobilization by selective activation of the alpha2 subunit of AMPK and increased energy utilization through activation of both the alpha1 and alpha2 subunits of AMPK. {yields} ANP enhanced adipocyte mitochondrial oxidative capacity as evidenced by induction of oxidative mitochondrial genes and increase in oxygen consumption. {yields} Exposure of human adipocytes to fatty acids and (TNF{alpha}) induced insulin resistance and decreased expression of mitochondrial genes which was restored to normal by ANP. -- Abstract: Atrial natriuretic peptide (ANP) has been shown to regulate lipid and carbohydrate metabolism providing a possible link between cardiovascular function and metabolism by mediating the switch from carbohydrate to lipid mobilization and oxidation. ANP exerts a potent lipolytic effect via cGMP-dependent protein kinase (cGK)-I mediated-stimulation of AMP-activated protein kinase (AMPK). Activation of the ANP/cGK signaling cascade also promotes muscle mitochondrial biogenesis and fat oxidation. Here we demonstrate that ANP regulates lipid metabolism and oxygen utilization in differentiated human adipocytes by activating the alpha2 subunit of AMPK. ANP treatment increased lipolysis by seven fold and oxygen consumption by two fold, both of which were attenuated by inhibition of AMPK activity. ANP-induced lipolysis was shown to be mediated by the alpha2 subunit of AMPK as introduction of dominant-negative alpha2 subunit of AMPK attenuated ANP effects on lipolysis. ANP-induced activation of AMPK enhanced mitochondrial oxidative capacity as evidenced by a two fold increase in oxygen consumption and induction of mitochondrial genes, including carnitine palmitoyltransferase 1A (CPT1a) by 1.4-fold, cytochrome C (CytC) by 1.3-fold, and

  11. Atrial natriuretic peptide regulates lipid mobilization and oxygen consumption in human adipocytes by activating AMPK

    International Nuclear Information System (INIS)

    Souza, Sandra C.; Chau, Mary D.L.; Yang, Qing; Gauthier, Marie-Soleil; Clairmont, Kevin B.; Wu, Zhidan; Gromada, Jesper; Dole, William P.

    2011-01-01

    Highlights: → Treatment of differentiated human adipocytes with atrial natriuretic peptide (ANP) increased lipolysis and oxygen consumption by activating AMP-activated protein kinase (AMPK). → ANP stimulated lipid mobilization by selective activation of the alpha2 subunit of AMPK and increased energy utilization through activation of both the alpha1 and alpha2 subunits of AMPK. → ANP enhanced adipocyte mitochondrial oxidative capacity as evidenced by induction of oxidative mitochondrial genes and increase in oxygen consumption. → Exposure of human adipocytes to fatty acids and (TNFα) induced insulin resistance and decreased expression of mitochondrial genes which was restored to normal by ANP. -- Abstract: Atrial natriuretic peptide (ANP) has been shown to regulate lipid and carbohydrate metabolism providing a possible link between cardiovascular function and metabolism by mediating the switch from carbohydrate to lipid mobilization and oxidation. ANP exerts a potent lipolytic effect via cGMP-dependent protein kinase (cGK)-I mediated-stimulation of AMP-activated protein kinase (AMPK). Activation of the ANP/cGK signaling cascade also promotes muscle mitochondrial biogenesis and fat oxidation. Here we demonstrate that ANP regulates lipid metabolism and oxygen utilization in differentiated human adipocytes by activating the alpha2 subunit of AMPK. ANP treatment increased lipolysis by seven fold and oxygen consumption by two fold, both of which were attenuated by inhibition of AMPK activity. ANP-induced lipolysis was shown to be mediated by the alpha2 subunit of AMPK as introduction of dominant-negative alpha2 subunit of AMPK attenuated ANP effects on lipolysis. ANP-induced activation of AMPK enhanced mitochondrial oxidative capacity as evidenced by a two fold increase in oxygen consumption and induction of mitochondrial genes, including carnitine palmitoyltransferase 1A (CPT1a) by 1.4-fold, cytochrome C (CytC) by 1.3-fold, and peroxisome proliferator

  12. Metabolic control over the oxygen consumption flux in intact skeletal muscle: in silico studies.

    Science.gov (United States)

    Liguzinski, Piotr; Korzeniewski, Bernard

    2006-12-01

    It has been postulated previously that a direct activation of all oxidative phosphorylation complexes in parallel with the activation of ATP usage and substrate dehydrogenation (the so-called each-step activation) is the main mechanism responsible for adjusting the rate of ATP production by mitochondria to the current energy demand during rest-to-work transition in intact skeletal muscle in vivo. The present in silico study, using a computer model of oxidative phosphorylation developed previously, analyzes the impact of the each-step-activation mechanism on the distribution of control (defined within Metabolic Control Analysis) over the oxygen consumption flux among the components of the bioenergetic system in intact oxidative skeletal muscle at different energy demands. It is demonstrated that in the absence of each-step activation, the oxidative phosphorylation complexes take over from ATP usage most of the control over the respiration rate and oxidative ATP production at higher (but still physiological) energy demands. This leads to a saturation of oxidative phosphorylation, impossibility of a further acceleration of oxidative ATP synthesis, and dramatic drop in the phosphorylation potential. On the other hand, the each-step-activation mechanism allows maintenance of a high degree of the control exerted by ATP usage over the ATP turnover and oxygen consumption flux even at high energy demands and thus enables a potentially very large increase in ATP turnover. It is also shown that low oxygen concentration shifts the metabolic control from ATP usage to cytochrome oxidase and thus limits the oxidative ATP production.

  13. The effect of neuromuscular blockade on oxygen consumption in sedated and mechanically ventilated pediatric patients after cardiac surgery.

    NARCIS (Netherlands)

    Lemson, J.; Driessen, J.J.; Hoeven, J.G. van der

    2008-01-01

    OBJECTIVE: To measure the effect of intense neuromuscular blockade (NMB) on oxygen consumption (VO(2)) in deeply sedated and mechanically ventilated children on the first day after complex congenital cardiac surgery. DESIGN: Prospective clinical interventional study. SETTING: Pediatric intensive

  14. NODC Standard Format Seabed Oxygen Consumption from In-Situ Sources (F050) Data (1974-1978) (NODC Accession 0014186)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data type contains data from analyses of seabed oxygen consumption determined from measurements over a specified time interval of initial and final dissolved...

  15. Oxygen consumption in Plasmodium berghei-infected murine red cells: a direct spectrophotometric assay in intact erythrocytes.

    Science.gov (United States)

    Deslauriers, R; Moffatt, D J; Smith, I C

    1986-05-29

    A spectrophotometric assay has been devised to measure oxygen consumption non-invasively in intact murine red cells parasitized by Plasmodium berghei. The method uses oxyhemoglobin in the erythrocytes both as a source of oxygen and as an indicator of oxygen consumption. Spectra of intact cells show broad peaks and sloping baselines due to light-scattering. In order to ascertain the number of varying components in the 370-450 nm range, the resolution of the spectra was enhanced using Fourier transforms of the frequency domain spectra. Calculation of oxygen consumption was carried out for two-component systems (oxyhemoglobin, deoxyhemoglobin) using absorbances at 415 and 431 nm. Samples prepared from highly parasitized mice (greater than 80% parasitemia, 5% hematocrit) showed oxygen consumption rates of (4-8) X 10(-8) microliter/cell per h. This rate was not attributable to the presence of white cells or reticulocytes. The rate of oxygen consumption in the erythrocytes is shown to be modulated by various agents: the respiratory inhibitors NaN3 and KCN (1 mM) reduced oxygen consumption 2-3-fold; salicylhydroxamic acid (2.5 mM) caused a 20% reduction in rate and 10 mM NaN3, completely blocked deoxygenation. Antimalarial drugs and metal-chelating agents were also tested. Chloroquine, EDTA and desferal (desferoxamine mesylate) did not decrease the deoxygenation rate of hemoglobin in parasitized cells. Quinacrine, quinine and primaquine reduced the rate of formation of deoxyhemoglobin but also produced substantial quantities of methemoglobin. The lipophilic chelator, 5-hydroxyquinoline, decreased the rate of deoxygenation one-third. The spectrophotometric assay provides a convenient means to monitor oxygen consumption in parasitized red cells, to test the effects of various agents thereon, and potentially to explore possible mechanisms for oxygen utilization.

  16. Quantifying salinity and season effects on eastern oyster clearance and oxygen consumption rates

    Science.gov (United States)

    Casas, S.M.; Lavaud, Romain; LaPeyre, Megan K.; Comeau, L. A.; Filgueira, R.; LaPeyre, Jerome F.

    2018-01-01

    There are few data on Crassostrea virginica physiological rates across the range of salinities and temperatures to which they are regularly exposed, and this limits the applicability of growth and production models using these data. The objectives of this study were to quantify, in winter (17 °C) and summer (27 °C), the clearance and oxygen consumption rates of C. virginica from Louisiana across a range of salinities typical of the region (3, 6, 9, 15 and 25). Salinity and season (temperature and reproduction) affected C. virginica physiology differently; salinity impacted clearance rates with reduced feeding rates at low salinities, while season had a strong effect on respiration rates. Highest clearance rates were found at salinities of 9–25, with reductions ranging from 50 to 80 and 90 to 95% at salinities of 6 and 3, respectively. Oxygen consumption rates in summer were four times higher than in winter. Oxygen consumption rates were within a narrow range and similar among salinities in winter, but varied greatly among individuals and salinities in summer. This likely reflected varying stages of gonad development. Valve movements measured at the five salinities indicated oysters were open 50–60% of the time in the 6–25 salinity range and ~ 30% at a salinity of 3. Reduced opening periods, concomitant with narrower valve gap amplitudes, are in accord with the limited feeding at the lowest salinity (3). These data indicate the need for increased focus on experimental determination of optimal ranges and thresholds to better quantify oyster population responses to environmental changes.

  17. Local cerebral blood flow and local oxygen consumption in prolonged hemiplegic migraine

    International Nuclear Information System (INIS)

    Baron, J.C.; Lebrun-Grandie, P.; Serdaru, M.; Bousser, M.G.; Lhermitte, F.; Cabanis, E.

    1982-09-01

    This work gives the results of a study by positron emission tomography of the cerebral blood flow (CBF), oxygen-extraction rate (O 2 E) and oxygen consumption (CMRO 2 ) during severe and prolonged attack of hemiplegic migraine. The salient facts observed are a high (CBF) in the brain hemisphere affected (ruling out the hypothesis of a persistent cerebral ischemia), together with a collapsed O 2 E (''luxury perfusion'') and especially preservation of the CMRO 2 suggesting a decoupling not only between CBF and CMRO 2 but also between CMRO 2 and functional state of the tissue. Some time after the attack a new study showed the recoupling between CBF and CMRO 2 , but with the latter reduced in the affected hemisphere although the clinical and tomodensitometric state had returned to normal. These new observations should not however be improperly generalised to all migraines, given the unusual characteristics of the disorder in our patient [fr

  18. Assessment of the oxygen consumption in the backfill. Geochemical modelling in a saturated backfill

    International Nuclear Information System (INIS)

    Grandia, Fidel; Domenech, Cristina; Arcos, David; Duro, Lara

    2006-11-01

    The consumption of oxygen in the deep disposal is a major concern due to the ability of this element to corrode the canisters where high level nuclear wastes (HLNW) are disposed. The anoxic conditions initially present in a deep geologic environment are disturbed by the excavation of the repository facilities. After sealing the deposition holes and tunnels using clay-based materials, oxygen remains dissolved in porewater or as a gas phase in the unsaturated pores. The main mechanisms of oxygen depletion that can be considered in the backfill materials are: (1) diffusion into the surrounding rock and (2) kinetic reactions with accessory minerals and organic matter existing in the backfill. In this report, a set of numerical simulations are carried out in one and two dimensions in order to test the effect on the oxygen concentration in the pore water of all these mechanisms. The backfill considered is a 0/70 mixture of MX-80 bentonite and crushed material from the excavation itself. In addition to organic matter, the solid phases with reducing capacity in the backfill are Fe(II)-bearing minerals: pyrite (FeS 2 ) and siderite (FeCO) (as accessory minerals in the bentonite) and Fe-biotite (from the crushed granite). In the simulations, other chemical processes like cation exchange and surface complexation onto clay surfaces, and thermodynamic equilibrium with calcite, gypsum and quartz are considered. Initial composition of porewater is obtained by equilibrating the Forsmark groundwater with the backfill material. The 1D simulation consists of a number of cells with no reactive minerals or organic matter representing granite. The central cell, however, contains oxygen and reactive minerals resembling a backfill. Oxygen is allowed to move only by diffusion. The 2D model simulates the interaction with a backfill of a granitic groundwater flowing through a fracture. Like in the 1D model, the backfill contains oxygen and reactive solids. The results are very similar in

  19. Assessment of the oxygen consumption in the backfill. Geochemical modelling in a saturated backfill

    Energy Technology Data Exchange (ETDEWEB)

    Grandia, Fidel; Domenech, Cristina; Arcos, David; Duro, Lara [Enviros Spain S.L., Barcelona (Spain)

    2006-11-15

    The consumption of oxygen in the deep disposal is a major concern due to the ability of this element to corrode the canisters where high level nuclear wastes (HLNW) are disposed. The anoxic conditions initially present in a deep geologic environment are disturbed by the excavation of the repository facilities. After sealing the deposition holes and tunnels using clay-based materials, oxygen remains dissolved in porewater or as a gas phase in the unsaturated pores. The main mechanisms of oxygen depletion that can be considered in the backfill materials are: (1) diffusion into the surrounding rock and (2) kinetic reactions with accessory minerals and organic matter existing in the backfill. In this report, a set of numerical simulations are carried out in one and two dimensions in order to test the effect on the oxygen concentration in the pore water of all these mechanisms. The backfill considered is a 0/70 mixture of MX-80 bentonite and crushed material from the excavation itself. In addition to organic matter, the solid phases with reducing capacity in the backfill are Fe(II)-bearing minerals: pyrite (FeS{sub 2}) and siderite (FeCO) (as accessory minerals in the bentonite) and Fe-biotite (from the crushed granite). In the simulations, other chemical processes like cation exchange and surface complexation onto clay surfaces, and thermodynamic equilibrium with calcite, gypsum and quartz are considered. Initial composition of porewater is obtained by equilibrating the Forsmark groundwater with the backfill material. The 1D simulation consists of a number of cells with no reactive minerals or organic matter representing granite. The central cell, however, contains oxygen and reactive minerals resembling a backfill. Oxygen is allowed to move only by diffusion. The 2D model simulates the interaction with a backfill of a granitic groundwater flowing through a fracture. Like in the 1D model, the backfill contains oxygen and reactive solids. The results are very similar in

  20. Four Weeks of Off-Season Training Improves Peak Oxygen Consumption in Female Field Hockey Players

    OpenAIRE

    Lindsey T. Funch; Erik Lind; Larissa True; Deborah Van Langen; John T. Foley; James F. Hokanson

    2017-01-01

    The purpose of the study was to examine the changes in peak oxygen consumption ( V ˙O2peak) and running economy (RE) following four-weeks of high intensity training and concurrent strength and conditioning during the off-season in collegiate female field hockey players. Fourteen female student-athletes (age 19.29 ± 0.91 years) were divided into two training groups, matched from baseline V ˙O2peak: High Intensity Training (HITrun; n = 8) and High Intensity Interval Training (HIIT; ...

  1. Molecular mechanisms regulating oxygen transport and consumption in high altitude and hibernating mammals

    DEFF Research Database (Denmark)

    Revsbech, Inge Grønvall

    2016-01-01

    The aim of this thesis is to broaden the knowledge of molecular mechanisms of adjustment in oxygen (O2) uptake, conduction, delivery and consumption in mammals adapted to extreme conditions. For this end, I have worked with animals living at high altitude as an example of environmental hypoxia...... of the repeatedly found adaptive traits in animals living at high altitude and in hibernating mammals during hibernation compared with the active state. Factors that affect O2 affinity of Hb include temperature, H+/CO2 via the Bohr effect as well as Cl- and organic phosphates, in mammals mainly 2...

  2. Oxygen consumption of elite distance runners on an anti-gravity treadmill®.

    Science.gov (United States)

    McNeill, David K P; Kline, John R; de Heer, Hendrick D; Coast, J Richard

    2015-06-01

    Lower body positive pressure (LBPP), or 'anti-gravity' treadmills® have become increasingly popular among elite distance runners. However, to date, few studies have assessed the effect of body weight support (BWS) on the metabolic cost of running among elite runners. This study evaluated how BWS influenced the relationship between velocity and metabolic cost among 6 elite male distance runners. Participants ran three- 16 minute tests consisting of 4 stages of 4 minutes at 8, 7, 6 and 5 min·mile(-1) pace (3.35, 3.84, 4.47 and 5.36 m·s(-1)), while maintaining an aerobic effort (Respiratory Exchange Ratio ≤1.00). One test was run on a regular treadmill, one on an anti-gravity treadmill with 40% BWS and one with 20% BWS being provided. Expired gas data were collected and regression equations used to determine and compare slopes. Significant decreases in oxygen uptake (V̇O2) were found with each increase in BWS (p rate, perceived exertion or directly measured oxygen uptake) should be used to guide training intensity when training on the LBPP treadmill. Key pointsWith increasing amounts of body weight-support (BWS), the slope of the relationship between velocity and oxygen consumption (ΔVO2/Δv) decreases significantly. This means the change in oxygen consumption (VO2) is significantly smaller over a given change in velocity at higher amounts of BWS.There is a non-linear decrease in VO2 with increasing BWS. As such, with each increment in the amount of BWS provided, the reduction in VO2 becomes increasingly smaller.This paper provides first of its kind data on the effects of BWS on the cost of running among highly trained, elite runners. The outcomes of this study are in line with previous findings among non-elite runners.

  3. Influence of radioprotectors on total body weight evolution and on oxygen consumption in lethal dose irradiated animals. (Preliminary study)

    International Nuclear Information System (INIS)

    Fatome, M.; Martine, G.; Bargy, E.; Andrieu, L.

    Comparison of total body weight evolution and oxygen consumption in lethal dose irradiated animals, protected by various well known radioprotective substances, isolated or in mixture, with evolution and consumption of non protected animals irradiated at the same dose and with these of check animals [fr

  4. PET imaging of cerebral perfusion and oxygen consumption in acute ischemic stroke: Relation to outcome

    International Nuclear Information System (INIS)

    Marchal, G.; Serrati, C.; Rioux, P.; Petit-Taboue, M.C.; Viader, F.; Sayette, V. de la; Doze, F. le; Lonchon, P; Derlon, J.M.; Orgogozo, J.M.; Baron, J.C.

    1993-01-01

    The authors used positron emission tomography (PET) to assess the relation between combined imaging of cerebral blood flow and oxygen consumption 5-18 h after first middle cerebral artery (MCA) stroke and neurological outcome at 2 months. All 18 patients could be classified into three visually defined PET patterns of perfusion and oxygen consumption changes. Pattern 1 suggested extensive irreversible damage and was consistently associated with poor outcome. Pattern 2 suggested continuing ischemia and was associated with variable outcome. Pattern 3 with hyperperfusion and little or no metabolic alteration, was associated with excellent recovery, which suggests that early reperfusion is beneficial. This relation between PET and outcome was highly significant. The results suggest that within 5-18 h of stroke onset, PET is a good predictor of outcome in patterns 1 and 3, for which therapy seems limited. The absence of predictive value for pattern 2 suggests that it is due to a reversible ischemic state that is possibly amenable to therapy. These findings may have important implications for acute MCA stroke management and for patients' selection for therapeutic trials

  5. Islet oxygen consumption rate (OCR) dose predicts insulin independence for first clinical islet allotransplants

    Science.gov (United States)

    Kitzmann, JP; O’Gorman, D; Kin, T; Gruessner, AC; Senior, P; Imes, S; Gruessner, RW; Shapiro, AMJ; Papas, KK

    2014-01-01

    Human islet allotransplant (ITx) for the treatment of type 1 diabetes is in phase III clinical registration trials in the US and standard of care in several other countries. Current islet product release criteria include viability based on cell membrane integrity stains, glucose stimulated insulin release (GSIR), and islet equivalent (IE) dose based on counts. However, only a fraction of patients transplanted with islets that meet or exceed these release criteria become insulin independent following one transplant. Measurements of islet oxygen consumption rate (OCR) have been reported as highly predictive of transplant outcome in many models. In this paper we report on the assessment of clinical islet allograft preparations using islet oxygen consumption rate (OCR) dose (or viable IE dose) and current product release assays in a series of 13 first transplant recipients. The predictive capability of each assay was examined and successful graft function was defined as 100% insulin independence within 45 days post-transplant. Results showed that OCR dose was most predictive of CTO. IE dose was also highly predictive, while GSIR and membrane integrity stains were not. In conclusion, OCR dose can predict CTO with high specificity and sensitivity and is a useful tool for evaluating islet preparations prior to clinical ITx. PMID:25131089

  6. Cerebral blood flow and oxygen consumption during ethanol withdrawal in the rat.

    Science.gov (United States)

    Hemmingsen, R; Barry, D I; Hertz, M M; Klinken, L

    1979-09-14

    The ethanol withdrawal syndrome in man and animals is characterized by signs of CNS hyperactivity although a direct measurement of a physiological variable reflecting this CNS hyperactivity has never been performed in untreated man or in animals. We induced ethanol dependence in the rat by means of intragastric intubation with a 20% w/v ethanol solution, thus keeping the animals in a state of continuous severe intoxication for 3--4 days; during the subsequent state of withdrawal characterized by tremor, rigidity, stereotyped movements and general seizures a 25% increase in cerebral oxygen consumption (CMRO2) could be measured; this increase was not due to catecholamines originating from adrenal medulla as adrenomedullectomized animals showed a similar increase in CMRO2 (28%); the withdrawing animals showed a corresponding cerebral blood flow (CBF) increase. The elevated CMRO2 and CBF could be reduced to normal by administration of a beta-adrenergic receptor blocker (propranolol 2 mg/kg i.v.), and hence the increased CMRO2 during ethanol withdrawal could be related to catecholaminergic systems in the brain, e.g. the noradrenergic locus coeruleus system which is anatomically well suited as a general activating system. This interpretation is supported by the earlier neurochemical finding of an increased cerebral noradrenaline turnover during ethanol withdrawal. The exact mechanism underlying the increased cerebral oxygen consumption during ethanol withdrawal and the effect of propranolol on cerebral function during this condition remains to be clarified.

  7. Regional myocardial oxygen consumption estimated by carbon-11 acetate and positron emission tomography before and after repetitive ischemia

    DEFF Research Database (Denmark)

    Kofoed, K F; Hansen, P R; Holm, S

    2000-01-01

    alternating with 5 minutes of reperfusion. Before and after repetitive coronary occlusions, oxygen 15 water/oxygen 15 carbon monoxide (blood flow), and 11C-acetate (oxygen consumption) PET imaging were performed. Left ventricular regional systolic wall thickening was measured with sonomicrometry. Forty......BACKGROUND: Preserved myocardial oxygen consumption estimated by carbon 11-acetate and positron emission tomography (PET) in myocardial regions with chronic but reversibly depressed contractile function in patients with ischemic heart disease have been suggested to be caused by repeated short......-five minutes after the ischemic episodes, systolic ventricular wall thickening was decreased by 90%, whereas myocardial blood flow was reduced by 21% compared with baseline values (P consumption was unaltered compared with the baseline level...

  8. Somatosensory evoked changes in cerebral oxygen consumption measured non-invasively in premature neonates

    Science.gov (United States)

    Roche-Labarbe, Nadege; Fenoglio, Angela; Radakrishnan, Harsha; Kocienski-Filip, Marcia; Carp, Stefan A.; Dubb, Jay; Boas, David A.; Grant, P. Ellen; Franceschini, Maria Angela

    2013-01-01

    The hemodynamic functional response is used as a reliable marker of neuronal activity in countless studies of brain function and cognition. In newborns and infants, however, conflicting results have appeared in the literature concerning the typical response, and there is little information on brain metabolism and functional activation. Measurement of all hemodynamic components and oxygen metabolism is critical for understanding neurovascular coupling in the developing brain. To this end, we combined multiple near infrared spectroscopy techniques to measure oxy- and deoxy-hemoglobin concentrations, cerebral blood volume (CBV), and relative cerebral blood flow (CBF) in the somatosensory cortex of 6 preterm neonates during passive tactile stimulation of the hand. By combining these measures we estimated relative changes in the cerebral metabolic rate of oxygen consumption (rCMRO2). CBF starts increasing immediately after stimulus onset, and returns to baseline before blood volume. This is consistent with the model of pre-capillary arteriole active dilation driving the CBF response, with a subsequent CBV increase influenced by capillaries and veins dilating passively to accommodate the extra blood. rCMRO2 estimated using the steady-state formulation shows a biphasic pattern: an increase immediately after stimulus onset, followed by a post-stimulus undershoot due to blood flow returning faster to baseline than oxygenation. However, assuming a longer mean transit time from the arterial to the venous compartment, due to the immature vascular system of premature infants, reduces the post-stimulus undershoot and increases the flow/consumption ratio to values closer to adult values reported in the literature. We are the first to report changes in local rCBF and rCMRO2 during functional activation in preterm infants. The ability to measure these variables in addition to hemoglobin concentration changes is critical for understanding neurovascular coupling in the developing

  9. Consumption and efficiency of a passenger car with a hydrogen/oxygen PEFC based hybrid electric drivetrain

    Energy Technology Data Exchange (ETDEWEB)

    Buechi, F.N.; Dietrich, P.; Tsukada, A.; Koetz, R.; Freunberger, S.A. [Paul Scherrer Institut, Electrochemistry Laboratory, CH-5232 Villigen PSI (Switzerland); Paganelli, G.; Laurent, D.; Varenne, P.; Delfino, A.; Magne, P.A.; Walser, D.; Olsommer, D. [Conception et Developpement Michelin, Route Andre-Piller 30, CH-1762 Givisiez (Switzerland)

    2007-08-15

    The main factors for reducing the consumption of a vehicle are reduction of curb weight, air drag and increase in the drivetrain efficiency. Highly efficient drivetrains can be developed based on PEFC technology and curb weight may be limited by an innovative vehicle construction. In this paper, data on consumption and efficiency of a four-place passenger vehicle with a curb weight of 850 kg and an H{sub 2}/O{sub 2} fed PEFC/Supercap hybrid electric powertrain are presented. Hydrogen consumption in the New European Driving Cycle is 0.67 kg H{sub 2}/100 km, which corresponds to a gasoline equivalent consumption of 2.5 l/100 km. When including the energy needed to supply pure oxygen, the calculated consumption increases from 0.67 to 0.69-0.79 kg H{sub 2}/100 km, depending on the method of oxygen production. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  10. A new method to measure local oxygen consumption in human skeletal muscle during dynamic exercise using near-infrared spectroscopy

    International Nuclear Information System (INIS)

    Binzoni, Tiziano; Cooper, Chris E; Wittekind, Anna L; Beneke, Ralph; Elwell, Clare E; Leung, Terence S; Van De Ville, Dimitri

    2010-01-01

    Near infrared spectroscopy (NIRS) can readily report on changes in blood volume and oxygenation. However, it has proved more problematic to measure real-time changes in blood flow and oxygen consumption. Here we report the development of a novel method using NIRS to measure local oxygen consumption in human muscle. The method utilizes the blood volume changes induced by the muscle pump during rhythmically contracting exercising skeletal muscle. We found that the saturation of the blood during the contraction phase was lower than that during the relaxation phase. The calculated oxygen drop was then divided by the contraction time to generate a value for the muscle oxygen consumption in the optical region of interest. As a test we measured the muscle oxygen consumption in the human vastus lateralis during exercise on a cycle ergometer by 11 trained male athletes (32 ± 11 years old) at 40% and 110% peak aerobic power. We saw an increase from 13.78 µmol 100 g −1 min −1 to 19.72 µmol 100 g −1 min −1 with the increase in power. The measurements are theoretically exempt from usual NIRS confounders such as myoglobin and adipose tissue and could provide a useful tool for studying human physiology

  11. Gait transition and oxygen consumption in swimming striped surfperch Embiotoca lateralis Agassiz

    DEFF Research Database (Denmark)

    Cannas, M.; Schaefer, J.; Domenici, P.

    2006-01-01

    A flow-through respirometer and swim tunnel was used to estimate the gait transition speed (Up-c) of striped surfperch Embiotoca lateralis, a labriform swimmer, and to investigate metabolic costs associated with gait transition. The Up-c was defined as the lowest speed at which fish decrease...... the use of pectoral fins significantly. While the tail was first recruited for manoeuvring at relatively low swimming speeds, the use of the tail at these low speeds [as low as 0·75 body (fork) lengths s-1, LF s-1) was rare (..., either in addition to pectoral fins or during burst-and-coast mode. Oxygen consumption increased exponentially with swimming speeds up to gait transition, and then levelled off. Similarly, cost of transport (CT) decreased with increasing speed, and then levelled off near Up-c. When speeds =Up...

  12. Metformin Targets Brown Adipose Tissue in vivo and Reduces Oxygen Consumption in vitro

    DEFF Research Database (Denmark)

    Breining, Peter; Jensen, Jonas B; Sundelin, Elias I

    2018-01-01

    basic metabolic rate, making BAT an attractive target for treatment of type 2 diabetes. Under the hypothesis that BAT is a metformin target tissue, we investigated in vivo uptake of [11 C]-metformin tracer in mice and studied in vitro effects of metformin on cultured human brown adipocytes. Injected [11......Metformin is the most widely prescribed oral antidiabetic drug worldwide. Despite well-documented beneficial effects on health outcomes in diabetic patients, the target organs that mediate the effects of metformin remain to be established. In adult humans, brown adipose tissue (BAT) can influence...... uptake. Gene expression profiles of OCTs in BAT revealed ample OCT3 expression in both human and mouse BAT. Incubation of a human brown adipocyte cell models with metformin reduced cellular oxygen consumption in a dose dependent manner. Collectively, these results support BAT as a putative metformin...

  13. Moderate dose of watercress and red radish does not reduce oxygen consumption during graded exhaustive exercise

    Directory of Open Access Journals (Sweden)

    Abbas Meamarbashi

    2014-06-01

    Full Text Available Objective: Very recent studies have reported positive effects of dietary nitrate on the oxygen consumption during exercise. This research aimed to study the effect of moderate dose of high-nitrate vegetables, watercress (Nasturtium officinale and red radish (Raphanus sativus compared with a control group on the incremental treadmill exercise test following a standard Bruce protocol controlled by computer. Materials and Methods: Group 1 consumed 100 g watercress (n=11, 109.5 mg nitrate/day, and group 2 consumed 100 g red radish (n=11, mg 173.2 mg nitrate/day for seven days, and control group (n=14 was prohibited from high nitrate intake. Results: During exercise, watercress group showed significant changes in the maximum values of Respiratory Exchange Ratio (RER (p

  14. Taurine Supplementation Improves Functional Capacity, Myocardial Oxygen Consumption, and Electrical Activity in Heart Failure.

    Science.gov (United States)

    Ahmadian, Mehdi; Dabidi Roshan, Valiollah; Ashourpore, Eadeh

    2017-07-04

    Taurine is an amino acid found abundantly in the heart in very high concentrations. It is assumed that taurine contributes to several physiological functions of mammalian cells, such as osmoregulation, anti-inflammation, membrane stabilization, ion transport modulation, and regulation of oxidative stress and mitochondrial protein synthesis. The objective of the current study was to evaluate the effectiveness of taurine supplementation on functional capacity, myocardial oxygen consumption, and electrical activity in patients with heart failure. In a double-blind and randomly designed study, 16 patients with heart failure were assigned to two groups: taurine (TG, n = 8) and placebo (PG, n = 8). TG received 500-mg taurine supplementation three times per day for two weeks. Significant decrease in the values of Q-T segments (p heart failure patients. Together, these findings support the view that taurine improves cardiac function and functional capacity in patients with heart failure. This idea warrants further study.

  15. Value of cerebral blood flow rate and regional oxygen consumption studies in cerebral ischaemia

    Energy Technology Data Exchange (ETDEWEB)

    Clanet, M

    1987-06-18

    Studies of experimentally-induced ischaemia have shown that the intensity of neuronal suffering is related to the fall in perfusion rate. Below a certain level, called functional threshold, cerebral function is reversibly altered, whereas at a lower level (tissue necrosis threshold) the damage inflicted on neurons is irreversible. Between these two thresholds lies a ''penumbra zone''. This concept of thresholds must be mitigated by 2 parameters: duration of ischaemia and selective vulnerability of the various structures affected. Variations in blood flow rate only indirectly affect the state of tissues. Techniques developed from positron emission tomography make it possible to evaluate the metabolic activity of brain tissue in vivo: oxygen consumption (CMRO/sub 2/), oxygen extraction (EO/sub 2/) and glucose consumption (CMRG) which are thus correlated to cerebral blood flow and cerebral blood volume, sometimes also to tissue pH. Normal relations between blood flow rate and metabolism may be altered. Misery perfusion reflects a fall in cerebral blood flow with an increase in EO/sub 2/ and often a decrease in CMRO/sub 2/, whereas luxury perfusion reflects an increase in cerebral blood flow rate with reduction of CMRO/sub 2/, EO/sub 2/ and CMRG. The type of alteration encountered in human ischaemia varies according to the nature of the accident: studies of transient accidents emphasize the different haemodynamic aspects of occlusion of the wider arteries. The metabolic and haemodynamic profiles of established ischaemic accidents vary according to their type and to the time of the study, reflecting the complexity of the physiopathological mechanisms involved; they are frequently associated with metabolic repercussions at a distance from the ischaemic focus, which supports the concept of diaschisis.

  16. Oxygen consumption and heart rate responses to isolated ballet exercise sets.

    Science.gov (United States)

    Rodrigues-Krause, Josianne; Dos Santos Cunha, Giovani; Alberton, Cristine Lima; Follmer, Bruno; Krause, Mauricio; Reischak-Oliveira, Alvaro

    2014-01-01

    Ballet stage performances are associated with higher cardiorespiratory demand than rehearsals and classes. Hence, new interest is emerging to create periodized training that enhances dancers' fitness while minimizing delayed exercise-induced fatigue and possible injuries. Finding out in what zones of intensity dancers work during different ballet movements may support the use of supplemental training adjusted to the needs of the individual dancer. Therefore, the main purpose of this study was to describe dancers' oxygen consumption (VO2) and heart rate (HR) responses during the performance of nine isolated ballet exercise sets, as correlated with their first and second ventilatory thresholds (VT1 and VT2). Twelve female ballet dancers volunteered for the study. Their maximum oxygen consumption (VO2max), VT1, and VT2 were determined by use of an incremental treadmill test. Nine sets of ballet movements were assessed: pliés, tendus, jetés, rond de jambes, fondus, grand adage (adage), grand battements, temps levés, and sautés. The sets were randomly executed and separated by 5 minute rest periods. ANOVA for repeated measurements followed by the Bonferroni Post-hoc test were applied (p ballet sets. This stratification followed closely, but not exactly, the variation in HR. For example, rond de jambes (156.8 ± 19 b·min(-1)) did not show any significant difference from all the other ballet sets, nor VT1 or VT2. It is concluded that the workloads of isolated ballet sets, based on VO2 responses, vary between low and moderate aerobic intensity in relation to dancers' VT1 and VT2. However, ballet set workloads may be higher when based on HR responses, due to the intermittent and isometric components of dance.

  17. Value of cerebral blood flow rate and regional oxygen consumption studies in cerebral ischaemia

    International Nuclear Information System (INIS)

    Clanet, M.

    1987-01-01

    Studies of experimentally-induced ischaemia have shown that the intensity of neuronal suffering is related to the fall in perfusion rate. Below a certain level, called functional threshold, cerebral function is reversibly altered, whereas at a lower level (tissue necrosis threshold) the damage inflicted on neurons is irreversible. Between these two thresholds lies a ''penumbra zone''. This concept of thresholds must be mitigated by 2 parameters: duration of ischaemia and selective vulnerability of the various structures affected. Variations in blood flow rate only indirectly affect the state of tissues. Techniques developed from positron emission tomography make it possible to evaluate the metabolic activity of brain tissue in vivo: oxygen consumption (CMRO 2 ), oxygen extraction (EO 2 ) and glucose consumption (CMRG) which are thus correlated to cerebral blood flow and cerebral blood volume, sometimes also to tissue pH. Normal relations between blood flow rate and metabolism may be altered. Misery perfusion reflects a fall in cerebral blood flow with an increase in EO 2 and often a decrease in CMRO 2 , whereas luxury perfusion reflects an increase in cerebral blood flow rate with reduction of CMRO 2 , EO 2 and CMRG. The type of alteration encountered in human ischaemia varies according to the nature of the accident: studies of transient accidents emphasize the different haemodynamic aspects of occlusion of the wider arteries. The metabolic and haemodynamic profiles of established ischaemic accidents vary according to their type and to the time of the study, reflecting the complexity of the physiopathological mechanisms involved; they are frequently associated with metabolic repercussions at a distance from the ischaemic focus, which supports the concept of diaschisis [fr

  18. A Stirred Microchamber for Oxygen Consumption Rate Measurements With Pancreatic Islets

    Science.gov (United States)

    Papas, Klearchos K.; Pisania, Anna; Wu, Haiyan; Weir, Gordon C.; Colton, Clark K.

    2010-01-01

    Improvements in pancreatic islet transplantation for treatment of diabetes are hindered by the absence of meaningful islet quality assessment methods. Oxygen consumption rate (OCR) has previously been used to assess the quality of organs and primary tissue for transplantation. In this study, we describe and characterize a stirred microchamber for measuring OCR with small quantities of islets. The device has a titanium body with a chamber volume of about 200 µL and is magnetically stirred and water jacketed for temperature control. Oxygen partial pressure (pO2) is measured by fluorescence quenching with a fiber optic probe, and OCR is determined from the linear decrease of pO2 with time. We demonstrate that measurements can be made rapidly and with high precision. Measurements with βTC3 cells and islets show that OCR is directly proportional to the number of viable cells in mixtures of live and dead cells and correlate linearly with membrane integrity measurements made with cells that have been cultured for 24 h under various stressful conditions. PMID:17497731

  19. Factors determining the oxygen consumption rate (VO2) on-kinetics in skeletal muscles.

    Science.gov (United States)

    Korzeniewski, Bernard; Zoladz, Jerzy A

    2004-05-01

    Using a computer model of oxidative phosphorylation developed previously [Korzeniewski and Mazat (1996) Biochem. J. 319, 143-148; Korzeniewski and Zoladz (2001) Biophys. Chem. 92, 17-34], we analyse the effect of several factors on the oxygen-uptake kinetics, especially on the oxygen consumption rate (VO2) and half-transition time t(1/2), at the onset of exercise in skeletal muscles. Computer simulations demonstrate that an increase in the total creatine pool [PCr+/-Cr] (where Cr stands for creatine and PCr for phosphocreatine) and in glycolytic ATP supply lengthen the half-transition time, whereas increase in mitochondrial content, in parallel activation of ATP supply and ATP usage, in oxygen concentration, in proton leak, in resting energy demand, in resting cytosolic pH and in initial alkalization decrease this parameter. Theoretical studies show that a decrease in the activity of creatine kinase (CK) [displacement of this enzyme from equilibrium during on-transient (rest-to-work transition)] accelerates the first stage of the VO2 on-transient, but slows down the second stage of this transient. It is also demonstrated that a prior exercise terminated a few minutes before the principal exercise shortens the transition time. Finally, it is shown that at a given ATP demand, and under conditions where CK works near the thermodynamic equilibrium, the half-transition time of VO2 kinetics is determined by the amount of PCr that has to be transformed into Cr during rest-to-work transition; therefore any factor that diminishes the difference in [PCr] between rest and work at a given energy demand will accelerate the VO2 on-kinetics. Our conclusions agree with the general idea formulated originally by Easterby [(1981) Biochem. J. 199, 155-161] that changes in metabolite concentrations determine the transition times between different steady states in metabolic systems.

  20. Effects of salinity and pH on the activity and oxygen consumption of Brachionus plicatilis (rotatoria)

    Energy Technology Data Exchange (ETDEWEB)

    Epp, R.W.; Winston, P.W.

    1978-01-01

    Activity and respiratory rates of the rotifer, Brachionus plicatilis, were determined following exposure to pH values of 6.5, 7.5 and 8.5 and to concentrations of 10, 50 and 100 mosm. Changes in the hydrogen-ion concentration had no detectable effect on either activity or metabolism. Acute reduction in osmolarity of the medium resulted in a reduction in oxygen consumption and activity. Both activity and oxygen consumption increased upon acclimatization to osmolarities of 50 and 100 mosm.

  1. Oxygen consumption rate and Na+/K+-ATPase activity in early developmental stages of the sea urchin Paracentrotus lividus Lam.

    Science.gov (United States)

    Tomšić, Sanja; Stanković, Suzana; Lucu, Čedomil

    2011-09-01

    Changes in oxygen consumption rate and Na+/K+-ATPase activity during early development were studied in the sea urchin Paracentrotus lividus Lam. The oxygen consumption rate increased from 0.12 μmol O2 mg protein-1 h-1 in unfertilized eggs to 0.38 μmol O2 mg protein-1 h-1 25 min after fertilization. Specific activity of the Na+/K+-ATPase was significantly stimulated after fertilization, ranging up to 1.07 μmol Pi h-1 mg protein-1 in the late blastula stage and slightly lower values in the early and late pluteus stages.

  2. The oxygen consumption rates of different life stages of the endoparasitic nematode

    Directory of Open Access Journals (Sweden)

    Willie van Aardt

    2010-01-01

    Full Text Available The oxygen consumption rates of different life stages of the endoparasitic nematode, Pratylenchus zeae (Nematoda: Tylenchida during non- and post-anhydrobiosisPratylenchus zeae, widely distributed in tropical and subtropical regions, is an endoparasite in roots of maize and other crop plants. The nematode is attracted to plant roots by CO2 and root exudates and feeds primarily on cells of the root cortex, making channels and openings where the eggs are deposited, with the result that secondary infection occurs due to bacteria and fungi. Nothing is known about the respiration physiology of this nematode and how it manages to survive during dry seasons. To measure the oxygen consumption rate (VO2 of individual P. zeae (less than half a millimeter long, a special measuring technique namely Cartesian diver micro-respirometry was applied. The Cartesian divers were machined from Perspex, and proved to be more accurate to measure VO2 compared with heavier glass divers used in similar experiments on free living nematodes. An accuracy of better than one nanoliter of oxygen consumed per hour was achieved with a single P. zeae inside the diver. Cartesian diver micro-respirometry measurements are based in principle on the manometric changes that occur in a fl otation tube in a manometer set-up when oxygen is consumed by P. zeae and CO2 from the animal is chemically absorbed. VO2 was measured for eggs (length: < 0.05 mm, larvae (length: 0.36 mm and adults (length: 0.47 mm before induction to anhydrobiosis. P. zeae from infected maize roots were extracted and exposed aseptically to in vitro maize root cultures in a grow cabinet at 50 % to 60% relative humidity at 28 ºC using eggs, larvae and adults. VO2 was also measured for post-anhydrobiotic eggs, larvae and adults by taking 50 individuals, eggs and larvae from the culture and placing them in Petri-dishes with 1% agar/water to dry out for 11 days at 28 ºC and 50% relative humidity. The VO2 was measured

  3. AquaResp® — free open-source software for measuring oxygen consumption of resting aquatic animals

    DEFF Research Database (Denmark)

    Svendsen, Morten Bo S.; Skov, Peter Vilhelm; Bushnell, Peter G.

    AquaResp® is a free open-source software program developed to measure the oxygen consumption of aquatic animals using intermittent flow techniques. This free program is based on Microsoft Excel, and uses the MCC Universal Library and a data acquisition board to acquire analogue readings from up...... to four input ports and output control via two digital and two analogue ports. In addition AquaResp can read one COM-port if the oxygen analyser has a RS-232 output signal. The present version of the program has options for parsing data strings generated by two major fibre optic oxygen electrode...

  4. Effects of zilpaterol hydrochloride on methane production, total body oxygen consumption, and blood metabolites in finishing beef steers

    Science.gov (United States)

    An indirect calorimetry experiment was conducted to determine the effects of feeding zilpaterol hydrochloride (ZH) for 20 d on total body oxygen consumption, respiratory quotient, methane production, and blood metabolites in finishing beef steers. Sixteen Angus steers (initial BW = 555 ± 12.7 kg) w...

  5. Effect of the Combination of Ezetimibe and Simvastatin on Gluconeogenesis and Oxygen Consumption in the Rat Liver.

    Science.gov (United States)

    Bracht, Lívia; Caparroz-Assef, Silvana Martins; Bracht, Adelar; Bersani-Amado, Ciomar Aparecida

    2016-06-01

    The aim of this work was to investigate the effects of chronic treatment with the combination of ezetimibe and simvastatin on gluconeogenesis in rat liver. Rats were treated daily for 28 days with the combination of ezetimibe and simvastatin (10/40 mg/kg) by oral gavage. To measure gluconeogenesis and the associated pathways, isolated perfused rat liver was used. In addition, subcellular fractions, such as microsomes and mitochondria, were used for complementary measures of enzymatic activities. Treatment with the combination of simvastatin and ezetimibe resulted in a decrease in gluconeogenesis from pyruvate (-62%). Basal oxygen consumption of the treated animals was higher (+22%) than that of the control rats, but the resulting oxygen consumption that occurred after pyruvate infusion was 43% lower in animals treated with the combination of simvastatin and ezetimibe. Oxygen consumption in the livers from treated animals was completely inhibited by cyanide (electron transport chain inhibitor), but not by proadifen (cytochrome P450 inhibitor). Chronic treatment with ezetimibe/simvastatin decreased the activity of the key enzymes glucose-6-phosphatase and fructose-1,6-bisphosphatase by 59% and 45%, respectively, which is probably the major reason for the decreased gluconeogenesis seen in ezetimibe-/simvastatin-treated rats. It is also possible that part of the effect of this combination on gluconeogenesis and on the oxygen consumption is related to the impairment of mitochondrial energy transduction. © 2015 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

  6. Regional myocardial oxygen consumption estimated by carbon-11 acetate and positron emission tomography before and after repetitive ischemia

    DEFF Research Database (Denmark)

    Kofoed, K F; Hansen, P R; Holm, S

    2011-01-01

    Preserved myocardial oxygen consumption estimated by carbon 11-acetate and positron emission tomography (PET) in myocardial regions with chronic but reversibly depressed contractile function in patients with ischemic heart disease have been suggested to be caused by repeated short episodes of acu...

  7. Modelling benthic oxygen consumption and benthic-pelagic coupling at a shallow station in the southern North Sea

    NARCIS (Netherlands)

    Provoost, P.; Braeckman, U.; Van Gansbeke, D.; Moodley, L.; Soetaert, K.; Middelburg, J.J.; Vanaverbeke, J.

    2013-01-01

    A time-series of benthic oxygen consumption, water-column and sediment chlorophyll concentrations, and temperature in the southern North Sea was subjected to inverse modelling in order to study benthic-pelagic coupling in this coastal marine system. The application of a Markov Chain Monte Carlo

  8. L-NIL prevents renal microvascular hypoxia and increase of renal oxygen consumption after ischemia-reperfusion in rats

    NARCIS (Netherlands)

    Legrand, Matthieu; Almac, Emre; Mik, Egbert G.; Johannes, Tanja; Kandil, Asli; Bezemer, Rick; Payen, Didier; Ince, Can

    2009-01-01

    Legrand M, Almac E, Mik EG, Johannes T, Kandil A, Bezemer R, Payen D, Ince C. L-NIL prevents renal microvascular hypoxia and increase of renal oxygen consumption after ischemia-reperfusion in rats. Am J Physiol Renal Physiol 296: F1109-F1117, 2009. First published February 18, 2009;

  9. Concurrent validity of the PAM accelerometer relative to the MTI Actigraph using oxygen consumption as a reference

    NARCIS (Netherlands)

    Slootmaker, S.M.; Chin A Paw, M.J.M.; Schuit, A.J.; Mechelen, W. van; Koppes, L.L.J.

    2009-01-01

    The purpose of this study was to examine the concurrent validity of the Personal Activity Monitor (PAM) accelerometer relative to the Actigraph accelerometer using oxygen consumption as a reference, and to assess the test-retest reliability of the PAM. Thirty-two fit, normal weight adults (aged

  10. Maximal oxygen consumption, respiratory volume and some related factors in fire-fighting personnel

    Directory of Open Access Journals (Sweden)

    Touraj Khazraee

    2017-01-01

    Full Text Available Background: Firefighters for difficult activities and rescue of damaged people must be in appropriate physical ability. Maximal oxygen capacity is an indicator for diagnosis of physical ability of workers. This study aimed to assess the cardiorespiratory system and its related factors in firefighters. Methods: This study was conducted on 110 firefighters from various stations. An self-administered questionnaire (respiratory disorders questionnaire, Tuxworth-Shahnavaz step test, and pulmonary function test was used to collection of required data. Average of humidity and temperature was 52% and 17°C, respectively. Background average noise levels were between 55 and 65 dB. Data were analyzed using SPSS software (version 19. Results: The mean age of the study participants was 32 ± 6.2 years. The means of forced vital capacity (FVC, forced expiratory volume in 1 s (FEV1, and FEV1/FVC were 92% ±9.4%, 87% ±9.2%, and 80% ±6.1%, respectively. The participants' mean VO2-max was 2.79 ± 0.29 L/min or 37.34 ± 4.27 ml/kg body weight per minute. The results revealed that weight has a direct association with vital capacity (VC, FVC, and peak expiratory flow. In addition, height was directly associated with VC, FVC, and VO2-max (P < 0.05. However, there was an inverse and significant association between height and FEV1/FVC (r = −0.23,P< 0.05. Height, weight, body mass index, and waist circumference were directly associated with VO2-max. Conclusions: The findings of this study showed that the amount of maximum oxygen consumption is close with the proposed range of this parameter among firefighters in other studies. Furthermore, the results of the study revealed that individuals had normal amounts of lung volume index. This issue can be attributed to the appropriate usage of respiratory masks.

  11. Using micro-patterned sensors and cell self-assembly for measuring the oxygen consumption rate of single cells

    International Nuclear Information System (INIS)

    Etzkorn, James R; Parviz, Babak A; Wu, Wen-Chung; Tian, Zhiyuan; Kim, Prince; Jang, Sei-Hum; Jen, Alex K-Y; Meldrum, Deirdre R

    2010-01-01

    We present a method for self-assembling arrays of live single cells on a glass chip using a photopatternable polymer to form micro-traps. We have studied the single-cell self-assembly method and optimized the process to obtain a 52% yield of single-trapped cells. We also report a method to measure the oxygen consumption rate of a single cell using micro-patterned sensors. These molecular oxygen sensors were fabricated around each micro-trap allowing optical interrogation of oxygen concentration in the immediate environment of the trapped cell. Micromachined micro-wells were then used to seal the trap, sensor and cell in order to determine the oxygen consumption rate of single cells. These techniques reported here add to the collection of tools for performing 'singe-cell' biology. An oxygen consumption rate of 1.05 ± 0.28 fmol min −1 was found for a data set consisting of 25 single A549 cells.

  12. Pectoral fin beat frequency predicts oxygen consumption during spontaneous activity in a labriform swimming fish (Embiotoca lateralis)

    DEFF Research Database (Denmark)

    Tudorache, Christian; Jordan, Anders D.; Svendsen, Jon Christian

    2009-01-01

    The objective of this study was to identify kinematic variables correlated with oxygen consumption during spontaneous labriform swimming. Kinematic variables (swimming speed, change of speed, turning angle, turning rate, turning radius and pectoral fin beat frequency) and oxygen consumption (MO2......) of spontaneous swimming in Embiotoca lateralis were measured in a circular arena using video tracking and respirometry, respectively. The main variable influencing MO2 was pectoral fin beat frequency (r (2) = 0.71). No significant relationship was found between swimming speed and pectoral fin beat frequency....... Complementary to other methods within biotelemetry such as EMG it is suggested that such correlations of pectoral fin beat frequency may be used to measure the energy requirements of labriform swimming fish such as E. lateralis in the field, but need to be taken with great caution since movement and oxygen...

  13. Sulfur Isotope Trends in Archean Microbialite Facies Record Early Oxygen Production and Consumption

    Science.gov (United States)

    Zerkle, A.; Meyer, N.; Izon, G.; Poulton, S.; Farquhar, J.; Claire, M.

    2014-12-01

    The major and minor sulfur isotope composition (δ34S and Δ33S) of pyrites preserved in ~2.65-2.5 billion-year-old (Ga) microbialites record localized oxygen production and consumption near the mat surface. These trends are preserved in two separate drill cores (GKF01 and BH1-Sacha) transecting the Campbellrand-Malmani carbonate platform (Ghaap Group, Transvaal Supergroup, South Africa; Zerkle et al., 2012; Izon et al., in review). Microbialite pyrites possess positive Δ33S values, plotting parallel to typical Archean trends (with a Δ33S/δ34S slope of ~0.9) but enriched in 34S by ~3 to 7‰. We propose that these 34S-enriched pyrites were formed from a residual pool of sulfide that was partially oxidized via molecular oxygen produced by surface mat-dwelling cyanobacteria. Sulfide, carrying the range of Archean Δ33S values, could have been produced deeper within the microbial mat by the reduction of sulfate and elemental sulfur, then fractionated upon reaction with O2 produced by oxygenic photosynthesis. Preservation of this positive 34S offset requires that: 1) sulfide was only partially (50­­-80%) consumed by oxidation, meaning H2S was locally more abundant (or more rapidly produced) than O2, and 2) the majority of the sulfate produced via oxidation was not immediately reduced to sulfide, implying either that the sulfate pool was much larger than the sulfide pool, or that the sulfate formed near the mat surface was transported and reduced in another part of the system. Contrastingly, older microbialite facies (> 2.7 Ga; Thomazo et al., 2013) appear to lack these observed 34S enrichments. Consequently, the onset of 34S enrichments could mark a shift in mat ecology, from communities dominated by anoxygenic photosynthesizers to cyanobacteria. Here, we test these hypotheses with new spatially resolved mm-scale trends in sulfur isotope measurements from pyritized stromatolites of the Vryburg Formation, sampled in the lower part of the BH1-Sacha core. Millimeter

  14. Mitigating an increase of specific power consumption in a cryogenic air separation unit at reduced oxygen production

    Science.gov (United States)

    Singla, Rohit; Chowdhury, Kanchan

    2017-02-01

    Specific power consumed in a Linde double column air separation unit (ASU) increases as the quantity of oxygen produced at a given purity is decreased due to the changes of system requirement or market demand. As the plant operates in part load condition, the specific power consumption (SPC) increases as the total power consumption remains the same. In order to mitigate the increase of SPC at lower oxygen production, the operating pressure of high pressure column (HPC) can be lowered by extending the low pressure column (LPC) by a few trays and adding a second reboiler. As the duty of second reboiler in LPC is increased, the recovery of oxygen decreases with a lowering of the HPC pressure. This results in mitigation of the increase of SPC of the plant. A Medium pressure ASU with dual reboiler that produces pressurised gaseous and liquid products of oxygen and nitrogen is simulated in Aspen Hysys 8.6®, a commercial process simulator to determine SPC at varying oxygen production. The effects of reduced pressure of air feed into the cold box on the size of heat exchangers (HX) are analysed. Operation strategy to obtain various oxygen production rates at varying demand is also proposed.

  15. Effect of limb cooling on peripheral and global oxygen consumption in neonates.

    Science.gov (United States)

    Hassan, I A-A; Wickramasinghe, Y A; Spencer, S A

    2003-03-01

    To evaluate peripheral oxygen consumption (VO(2)) measurements using near infrared spectroscopy (NIRS) with arterial occlusion in healthy term neonates by studying the effect of limb cooling on peripheral and global VO(2). Twenty two healthy term neonates were studied. Peripheral VO(2) was measured by NIRS using arterial occlusion and measurement of the oxyhaemoglobin (HbO(2)) decrement slope. Global VO(2) was measured by open circuit calorimetry. Global and peripheral VO(2) was measured in each neonate before and after limb cooling. In 10 neonates, a fall in forearm temperature of 2.2 degrees C (mild cooling) decreased forearm VO(2) by 19.6% (p forearm temperature of 4 degrees C (moderate cooling) decreased forearm VO(2) by 34.7% (p cooling. The changes are more pronounced with moderate limb cooling when a concomitant rise in global VO(2) is observed. Change in peripheral temperature must be taken into consideration in the interpretation of peripheral VO(2) measurements in neonates.

  16. Long-term fasting decreases mitochondrial avian UCP-mediated oxygen consumption in hypometabolic king penguins.

    Science.gov (United States)

    Rey, Benjamin; Halsey, Lewis G; Dolmazon, Virginie; Rouanet, Jean-Louis; Roussel, Damien; Handrich, Yves; Butler, Patrick J; Duchamp, Claude

    2008-07-01

    In endotherms, regulation of the degree of mitochondrial coupling affects cell metabolic efficiency. Thus it may be a key contributor to minimizing metabolic rate during long periods of fasting. The aim of the present study was to investigate whether variation in mitochondrial avian uncoupling proteins (avUCP), as putative regulators of mitochondrial oxidative phosphorylation, may contribute to the ability of king penguins (Aptenodytes patagonicus) to withstand fasting for several weeks. After 20 days of fasting, king penguins showed a reduced rate of whole animal oxygen consumption (Vo2; -33%) at rest, together with a reduced abundance of avUCP and peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC1-alpha) mRNA in pectoralis muscle (-54%, -36%, respectively). These parameters were restored after the birds had been refed for 3 days. Furthermore, in recently fed, but not in fasted penguins, isolated muscle mitochondria showed a guanosine diphosphate-inhibited, fatty acid plus superoxide-activated respiration, indicating the presence of a functional UCP. It was calculated that variation in mitochondrial UCP-dependent respiration in vitro may contribute to nearly 20% of the difference in resting Vo2 between fed or refed penguins and fasted penguins measured in vivo. These results suggest that the lowering of avUCP activity during periods of long-term energetic restriction may contribute to the reduction in metabolic rate and hence the ability of king penguins to face prolonged periods of fasting.

  17. Plasma osmolality and oxygen consumption of perch Perca fluviatilis in response to different salinities and temperatures

    DEFF Research Database (Denmark)

    Christensen, Emil Aputsiaq Flindt; Svendsen, Morten Bo Søndergaard; Steffensen, John Fleng

    2017-01-01

    with salinity at 10 and 20° C. Maximum metabolic rate (MMR) and aerobic scope was lowest at salinity of 15 at 5° C, yet at 20° C, they were lowest at a salinity of 0. A cost of osmoregulation (SMR at a salinity of 0 and 15 compared with SMR at a salinity of 10) could only be detected at a salinity of 15 at 20...... of osmoregulation (28%) at a salinity of 15 at 20° C indicates that the cost of osmoregulation in P. fluviatilis increases with temperature under hyperosmotic conditions and a power analysis showed that the cost of osmoregulation could be lower than 12·5% under other environmental conditions. The effect of salinity......The present study determined the blood plasma osmolality and oxygen consumption of the perch Perca fluviatilis at different salinities (0, 10 and 15) and temperatures (5, 10 and 20° C). Blood plasma osmolality increased with salinity at all temperatures. Standard metabolic rate (SMR) increased...

  18. Selection for high and low oxygen consumption-induced differences in maintenance energy requirements of mice.

    Science.gov (United States)

    Darhan, Hongyu; Kikusato, Motoi; Toyomizu, Masaaki; Roh, Sang-Gun; Katoh, Kazuo; Sato, Masahiro; Suzuki, Keiichi

    2017-07-01

    Maintenance energy requirements (MER) of mice selected for high (H) or low (L) oxygen consumption (OC) were compared. Forty-four mice from H and L OC lines were weaned at 3 weeks and divided into four experimental groups: group A were sacrificed at 4 weeks; group B were fed ad libitum, and groups C and D were fed 2.8 and 2.4 g/day, respectively, from 4 to 8 weeks of age. Groups B-D were sacrificed at 8 weeks. Chemical components were estimated for all groups. MER was estimated using a model that partitioned metabolizable energy intake into that used for maintenance, and protein and fat deposition. The feed conversion ratio for the B group was significantly higher in the H than in the L line. Feed intake for metabolic energy content per metabolic body size was significantly also higher in the H line, whereas accumulated energy content per metabolic body size was significantly higher in the L line. MER of the H line was greater than that of the L line (P < 0.10). These results suggest that selection for H or L OC produced differences in chemical components, feed efficiency, and MER between the H and L lines. © 2016 Japanese Society of Animal Science.

  19. Hypoxic training increases maximal oxygen consumption in Thoroughbred horses well-trained in normoxia.

    Science.gov (United States)

    Ohmura, Hajime; Mukai, Kazutaka; Takahashi, Yuji; Takahashi, Toshiyuki; Jones, James H

    2017-01-01

    Hypoxic training is effective for improving athletic performance in humans. It increases maximal oxygen consumption (V̇O 2 max) more than normoxic training in untrained horses. However, the effects of hypoxic training on well-trained horses are unclear. We measured the effects of hypoxic training on V̇O 2 max of 5 well-trained horses in which V̇O 2 max had not increased over 3 consecutive weeks of supramaximal treadmill training in normoxia which was performed twice a week. The horses trained with hypoxia (15% inspired O 2 ) twice a week. Cardiorespiratory valuables were analyzed with analysis of variance between before and after 3 weeks of hypoxic training. Mass-specific V̇O 2 max increased after 3 weeks of hypoxic training (178 ± 10 vs. 194 ± 12.3 ml O 2 (STPD)/(kg × min), Phorses, at least for the durations of time evaluated in this study. Training while breathing hypoxic gas may have the potential to enhance normoxic performance of Thoroughbred horses.

  20. Temperature induced variation in oxygen consumption of juvenile and adult stage of the dog conch Laevistrombus canarium (Linnaeus 1758)

    Science.gov (United States)

    Hassan, Wan Nurul Husna Wan; Amin, S. M. Nurul; Ghaffar, Mazlan Abd; Cob, Zaidi Che

    2015-09-01

    Laevistrombus canarium Linnaeus, 1758 is one of the important edible sea snail within the western Johor Straits, Malaysia. In this study, the impact of temperature on oxygen consumption (MO2) of L. canarium based on their ontogenetic changes (juvenile and adult) was measured in the laboratory condition at 22.0, 26.0, 30.0 and 34.0°C. Measurement of MO2 were taken every 1 s for 60 min on 4.20 - 34.00 g dog conch using respirometry chamber. All experiments were carried out in static conditions in five replicates with one snail per chambers. The results of oxygen consumption showed that juvenile dog conch respired at the rate of 0.163 ml h-1 and adult respired at the rate of 0.119 ml h-1. Consequently, the oxygen consumption in juvenile and adult dog conch was expressed as a total energy spends. The results indicates that total energy spend for oxygen consumed (ml h-1) of L. canarium at different temperature regimes (22.0 to 34.0°C) slightly increased over time period (0.63 ± 0.12 to 3.24 ± 0.05 J h-1) respectively. This finding of the present study suggested L. canarium is well adapted for life in high temperature environment.

  1. Oxygen consumption rate v. rate of energy utilization of fishes: a comparison and brief history of the two measurements.

    Science.gov (United States)

    Nelson, J A

    2016-01-01

    Accounting for energy use by fishes has been taking place for over 200 years. The original, and continuing gold standard for measuring energy use in terrestrial animals, is to account for the waste heat produced by all reactions of metabolism, a process referred to as direct calorimetry. Direct calorimetry is not easy or convenient in terrestrial animals and is extremely difficult in aquatic animals. Thus, the original and most subsequent measurements of metabolic activity in fishes have been measured via indirect calorimetry. Indirect calorimetry takes advantage of the fact that oxygen is consumed and carbon dioxide is produced during the catabolic conversion of foodstuffs or energy reserves to useful ATP energy. As measuring [CO2 ] in water is more challenging than measuring [O2 ], most indirect calorimetric studies on fishes have used the rate of O2 consumption. To relate measurements of O2 consumption back to actual energy usage requires knowledge of the substrate being oxidized. Many contemporary studies of O2 consumption by fishes do not attempt to relate this measurement back to actual energy usage. Thus, the rate of oxygen consumption (M˙O2 ) has become a measurement in its own right that is not necessarily synonymous with metabolic rate. Because all extant fishes are obligate aerobes (many fishes engage in substantial net anaerobiosis, but all require oxygen to complete their life cycle), this discrepancy does not appear to be of great concern to the fish biology community, and reports of fish oxygen consumption, without being related to energy, have proliferated. Unfortunately, under some circumstances, these measures can be quite different from one another. A review of the methodological history of the two measurements and a look towards the future are included. © 2016 The Fisheries Society of the British Isles.

  2. Validated Predictions of Metabolic Energy Consumption for Submaximal Effort Movement

    OpenAIRE

    Tsianos, George A.; MacFadden, Lisa N.

    2016-01-01

    Author Summary Muscles consume metabolic energy to generate movement. Performing a movement over a long period of time or at a high intensity strains the respiratory and cardiovascular systems that need to replenish the energy reserves in muscle. Furthermore, consuming and replenishing metabolic energy involves biochemical reactions with byproducts that cause muscle fatigue. These biochemical reactions also produce heat that increases body temperature, potentially causing central fatigue. A m...

  3. Predicted consequences of diabetes and SGLT inhibition on transport and oxygen consumption along a rat nephron

    Science.gov (United States)

    Vallon, Volker; Edwards, Aurélie

    2016-01-01

    Diabetes increases the reabsorption of Na+ (TNa) and glucose via the sodium-glucose cotransporter SGLT2 in the early proximal tubule (S1-S2 segments) of the renal cortex. SGLT2 inhibitors enhance glucose excretion and lower hyperglycemia in diabetes. We aimed to investigate how diabetes and SGLT2 inhibition affect TNa and sodium transport-dependent oxygen consumption QO2active along the whole nephron. To do so, we developed a mathematical model of water and solute transport from the Bowman space to the papillary tip of a superficial nephron of the rat kidney. Model simulations indicate that, in the nondiabetic kidney, acute and chronic SGLT2 inhibition enhances active TNa in all nephron segments, thereby raising QO2active by 5–12% in the cortex and medulla. Diabetes increases overall TNa and QO2active by ∼50 and 100%, mainly because it enhances glomerular filtration rate (GFR) and transport load. In diabetes, acute and chronic SGLT2 inhibition lowers QO2active in the cortex by ∼30%, due to GFR reduction that lowers proximal tubule active TNa, but raises QO2active in the medulla by ∼7%. In the medulla specifically, chronic SGLT2 inhibition is predicted to increase QO2active by 26% in late proximal tubules (S3 segments), by 2% in medullary thick ascending limbs (mTAL), and by 9 and 21% in outer and inner medullary collecting ducts (OMCD and IMCD), respectively. Additional blockade of SGLT1 in S3 segments enhances glucose excretion, reduces QO2active by 33% in S3 segments, and raises QO2active by SGLT2 blockade in diabetes lowers cortical QO2active and raises medullary QO2active, particularly in S3 segments. PMID:26764207

  4. Islet Oxygen Consumption Rate (OCR) Dose Predicts Insulin Independence in Clinical Islet Autotransplantation.

    Science.gov (United States)

    Papas, Klearchos K; Bellin, Melena D; Sutherland, David E R; Suszynski, Thomas M; Kitzmann, Jennifer P; Avgoustiniatos, Efstathios S; Gruessner, Angelika C; Mueller, Kathryn R; Beilman, Gregory J; Balamurugan, Appakalai N; Loganathan, Gopalakrishnan; Colton, Clark K; Koulmanda, Maria; Weir, Gordon C; Wilhelm, Josh J; Qian, Dajun; Niland, Joyce C; Hering, Bernhard J

    2015-01-01

    Reliable in vitro islet quality assessment assays that can be performed routinely, prospectively, and are able to predict clinical transplant outcomes are needed. In this paper we present data on the utility of an assay based on cellular oxygen consumption rate (OCR) in predicting clinical islet autotransplant (IAT) insulin independence (II). IAT is an attractive model for evaluating characterization assays regarding their utility in predicting II due to an absence of confounding factors such as immune rejection and immunosuppressant toxicity. Membrane integrity staining (FDA/PI), OCR normalized to DNA (OCR/DNA), islet equivalent (IE) and OCR (viable IE) normalized to recipient body weight (IE dose and OCR dose), and OCR/DNA normalized to islet size index (ISI) were used to characterize autoislet preparations (n = 35). Correlation between pre-IAT islet product characteristics and II was determined using receiver operating characteristic analysis. Preparations that resulted in II had significantly higher OCR dose and IE dose (p<0.001). These islet characterization methods were highly correlated with II at 6-12 months post-IAT (area-under-the-curve (AUC) = 0.94 for IE dose and 0.96 for OCR dose). FDA/PI (AUC = 0.49) and OCR/DNA (AUC = 0.58) did not correlate with II. OCR/DNA/ISI may have some utility in predicting outcome (AUC = 0.72). Commonly used assays to determine whether a clinical islet preparation is of high quality prior to transplantation are greatly lacking in sensitivity and specificity. While IE dose is highly predictive, it does not take into account islet cell quality. OCR dose, which takes into consideration both islet cell quality and quantity, may enable a more accurate and prospective evaluation of clinical islet preparations.

  5. Islet Oxygen Consumption Rate (OCR Dose Predicts Insulin Independence in Clinical Islet Autotransplantation.

    Directory of Open Access Journals (Sweden)

    Klearchos K Papas

    Full Text Available Reliable in vitro islet quality assessment assays that can be performed routinely, prospectively, and are able to predict clinical transplant outcomes are needed. In this paper we present data on the utility of an assay based on cellular oxygen consumption rate (OCR in predicting clinical islet autotransplant (IAT insulin independence (II. IAT is an attractive model for evaluating characterization assays regarding their utility in predicting II due to an absence of confounding factors such as immune rejection and immunosuppressant toxicity.Membrane integrity staining (FDA/PI, OCR normalized to DNA (OCR/DNA, islet equivalent (IE and OCR (viable IE normalized to recipient body weight (IE dose and OCR dose, and OCR/DNA normalized to islet size index (ISI were used to characterize autoislet preparations (n = 35. Correlation between pre-IAT islet product characteristics and II was determined using receiver operating characteristic analysis.Preparations that resulted in II had significantly higher OCR dose and IE dose (p<0.001. These islet characterization methods were highly correlated with II at 6-12 months post-IAT (area-under-the-curve (AUC = 0.94 for IE dose and 0.96 for OCR dose. FDA/PI (AUC = 0.49 and OCR/DNA (AUC = 0.58 did not correlate with II. OCR/DNA/ISI may have some utility in predicting outcome (AUC = 0.72.Commonly used assays to determine whether a clinical islet preparation is of high quality prior to transplantation are greatly lacking in sensitivity and specificity. While IE dose is highly predictive, it does not take into account islet cell quality. OCR dose, which takes into consideration both islet cell quality and quantity, may enable a more accurate and prospective evaluation of clinical islet preparations.

  6. A computational model for simulating solute transport and oxygen consumption along the nephrons

    Science.gov (United States)

    Vallon, Volker; Edwards, Aurélie

    2016-01-01

    The goal of this study was to investigate water and solute transport, with a focus on sodium transport (TNa) and metabolism along individual nephron segments under differing physiological and pathophysiological conditions. To accomplish this goal, we developed a computational model of solute transport and oxygen consumption (QO2) along different nephron populations of a rat kidney. The model represents detailed epithelial and paracellular transport processes along both the superficial and juxtamedullary nephrons, with the loop of Henle of each model nephron extending to differing depths of the inner medulla. We used the model to assess how changes in TNa may alter QO2 in different nephron segments and how shifting the TNa sites alters overall kidney QO2. Under baseline conditions, the model predicted a whole kidney TNa/QO2, which denotes the number of moles of Na+ reabsorbed per moles of O2 consumed, of ∼15, with TNa efficiency predicted to be significantly greater in cortical nephron segments than in medullary segments. The TNa/QO2 ratio was generally similar among the superficial and juxtamedullary nephron segments, except for the proximal tubule, where TNa/QO2 was ∼20% higher in superficial nephrons, due to the larger luminal flow along the juxtamedullary proximal tubules and the resulting higher, flow-induced transcellular transport. Moreover, the model predicted that an increase in single-nephron glomerular filtration rate does not significantly affect TNa/QO2 in the proximal tubules but generally increases TNa/QO2 along downstream segments. The latter result can be attributed to the generally higher luminal [Na+], which raises paracellular TNa. Consequently, vulnerable medullary segments, such as the S3 segment and medullary thick ascending limb, may be relatively protected from flow-induced increases in QO2 under pathophysiological conditions. PMID:27707705

  7. Preliminary observations in systemic oxygen consumption during targeted temperature management after cardiac arrest.

    Science.gov (United States)

    Uber, Amy; Grossestreuer, Anne V; Ross, Catherine E; Patel, Parth V; Trehan, Ambica; Donnino, Michael W; Berg, Katherine M

    2018-06-01

    Limited data suggests low oxygen consumption (VO 2 ), driven by mitochondrial injury, is associated with mortality after cardiac arrest. Due to the challenges of measurement in the critically ill, post-arrest metabolism remains poorly characterized. We monitored VO 2 , carbon dioxide production (VCO 2 ) and the respiratory quotient (RQ) in post-arrest patients and explored associations with outcome. Using a gas exchange monitor, we measured continuous VO 2 and VCO 2 in post- arrest patients treated with targeted temperature management. We used area under the curve and medians over time to evaluate the association between VO 2 , VCO 2 , RQ and the VO 2 :lactate ratio with survival. In 17 patients, VO 2 in the first 12 h after return of spontaneous circulation (ROSC) was associated with survival (median in survivors 3.35 mL/kg/min [2.98,3.88] vs. non-survivors 2.61 mL/kg/min [2.21,2.94], p = .039). This did not persist over 24 h. The VO 2 :lactate ratio was associated with survival (median in survivors 1.4 [IQR: 1.1,1.7] vs. non-survivors 0.8 [IQR: 0.6,1.2] p  0.7 (p = .131). VCO 2 was not associated with survival. There was a significant association between VO 2 and mortality in the first 12 h after ROSC, but not over 24 h. Lower VO 2: lactate ratio was associated with mortality. A large percentage of patients had RQs below physiologic norms. Further research is needed to explore whether these parameters could have true prognostic value or be a potential treatment target. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. Four Weeks of Off-Season Training Improves Peak Oxygen Consumption in Female Field Hockey Players

    Directory of Open Access Journals (Sweden)

    Lindsey T. Funch

    2017-11-01

    Full Text Available The purpose of the study was to examine the changes in peak oxygen consumption ( V ˙O2peak and running economy (RE following four-weeks of high intensity training and concurrent strength and conditioning during the off-season in collegiate female field hockey players. Fourteen female student-athletes (age 19.29 ± 0.91 years were divided into two training groups, matched from baseline V ˙O2peak: High Intensity Training (HITrun; n = 8 and High Intensity Interval Training (HIIT; n = 6. Participants completed 12 training sessions. HITrun consisted of 30 min of high-intensity running, while HIIT consisted of a series of whole-body high intensity Tabata-style intervals (75–85% of age predicted maximum heart rate for a total of four minutes. In addition to the interval training, the off-season training included six resistance training sessions, three team practices, and concluded with a team scrimmage. V ˙O2peak was measured pre- and post-training to determine the effectiveness of the training program. A two-way mixed (group × time ANOVA showed a main effect of time with a statistically significant difference in V ˙O2peak from pre- to post-testing, F(1, 12 = 12.657, p = 0.004, partial η2 = 0.041. Average (±SD V ˙O2peak increased from 44.64 ± 3.74 to 47.35 ± 3.16 mL·kg−1·min−1 for HIIT group and increased from 45.39 ± 2.80 to 48.22 ± 2.42 mL·kg−1·min−1 for HITrun group. Given the similar improvement in aerobic power, coaches and training staff may find the time saving element of HIIT-type conditioning programs attractive.

  9. Characterization of Adipose Tissue Product Quality Using Measurements of Oxygen Consumption Rate.

    Science.gov (United States)

    Suszynski, Thomas M; Sieber, David A; Mueller, Kathryn; Van Beek, Allen L; Cunningham, Bruce L; Kenkel, Jeffrey M

    2018-03-14

    Fat grafting is a common procedure in plastic surgery but associated with unpredictable graft retention. Adipose tissue (AT) "product" quality is affected by the methods used for harvest, processing and transfer, which vary widely amongst surgeons. Currently, there is no method available to accurately assess the quality of AT. In this study, we present a novel method for the assessment of AT product quality through direct measurements of oxygen consumption rate (OCR). OCR has exhibited potential in predicting outcomes following pancreatic islet transplant. Our study aim was to reapportion existing technology for its use with AT preparations and to confirm that these measurements are feasible. OCR was successfully measured for en bloc and postprocessed AT using a stirred microchamber system. OCR was then normalized to DNA content (OCR/DNA), which represents the AT product quality. Mean (±SE) OCR/DNA values for fresh en bloc and post-processed AT were 149.8 (± 9.1) and 61.1 (± 6.1) nmol/min/mg DNA, respectively. These preliminary data suggest that: (1) OCR and OCR/DNA measurements of AT harvested using conventional protocol are feasible; and (2) standard AT processing results in a decrease in overall AT product quality. OCR measurements of AT using existing technology can be done and enables accurate, real-time, quantitative assessment of the quality of AT product prior to transfer. The availability and further validation of this type of assay could enable optimization of fat grafting protocol by providing a tool for the more detailed study of procedural variables that affect AT product quality.

  10. PTP1B controls non-mitochondrial oxygen consumption by regulating RNF213 to promote tumour survival during hypoxia.

    Science.gov (United States)

    Banh, Robert S; Iorio, Caterina; Marcotte, Richard; Xu, Yang; Cojocari, Dan; Rahman, Anas Abdel; Pawling, Judy; Zhang, Wei; Sinha, Ankit; Rose, Christopher M; Isasa, Marta; Zhang, Shuang; Wu, Ronald; Virtanen, Carl; Hitomi, Toshiaki; Habu, Toshiyuki; Sidhu, Sachdev S; Koizumi, Akio; Wilkins, Sarah E; Kislinger, Thomas; Gygi, Steven P; Schofield, Christopher J; Dennis, James W; Wouters, Bradly G; Neel, Benjamin G

    2016-07-01

    Tumours exist in a hypoxic microenvironment and must limit excessive oxygen consumption. Hypoxia-inducible factor (HIF) controls mitochondrial oxygen consumption, but how/if tumours regulate non-mitochondrial oxygen consumption (NMOC) is unknown. Protein-tyrosine phosphatase-1B (PTP1B) is required for Her2/Neu-driven breast cancer (BC) in mice, although the underlying mechanism and human relevance remain unclear. We found that PTP1B-deficient HER2(+) xenografts have increased hypoxia, necrosis and impaired growth. In vitro, PTP1B deficiency sensitizes HER2(+) BC lines to hypoxia by increasing NMOC by α-KG-dependent dioxygenases (α-KGDDs). The moyamoya disease gene product RNF213, an E3 ligase, is negatively regulated by PTP1B in HER2(+) BC cells. RNF213 knockdown reverses the effects of PTP1B deficiency on α-KGDDs, NMOC and hypoxia-induced death of HER2(+) BC cells, and partially restores tumorigenicity. We conclude that PTP1B acts via RNF213 to suppress α-KGDD activity and NMOC. This PTP1B/RNF213/α-KGDD pathway is critical for survival of HER2(+) BC, and possibly other malignancies, in the hypoxic tumour microenvironment.

  11. FORMING SELF-ASSEMBLED CELL ARRAYS AND MEASURING THE OXYGEN CONSUMPTION RATE OF A SINGLE LIVE CELL.

    Science.gov (United States)

    Etzkorn, James R; McQuaide, Sarah C; Anderson, Judy B; Meldrum, Deirdre R; Parviz, Babak A

    2009-06-01

    We report a method for forming arrays of live single cells on a chip using polymer micro-traps made of SU8. We have studied the toxicity of the microfabricated structures and the associated environment for two cell lines. We also report a method for measuring the oxygen consumption rate of a single cell using optical interrogation of molecular oxygen sensors placed in micromachined micro-wells by temporarily sealing the cells in the micro-traps. The new techniques presented here add to the collection of tools available for performing "single-cell" biology. A single-cell self-assembly yield of 61% was achieved with oxygen draw down rates of 0.83, 0.82, and 0.71 fmol/minute on three isolated live A549 cells.

  12. Oxygen consumption during mineralization of organic compounds in water samples from a small sub-tropical reservoir (Brazil

    Directory of Open Access Journals (Sweden)

    Cunha-Santino Marcela Bianchessi da

    2003-01-01

    Full Text Available Assays were carried out to evaluate the oxygen consumption resulting from mineralization of different organic compounds: glucose, sucrose, starch, tannic acid, lysine and glycine. The compounds were added to 1 l of water sample from Monjolinho Reservoir. Dissolved oxygen and dissolved organic carbon were monitored during 20 days and the results were fitted to first order kinetics model. During the 20 days of experiments, the oxygen consumption varied from 4.5 mg.l-1 (tannic acid to 71.5 mg.l-1 (glucose. The highest deoxygenation rate (kD was observed for mineralization of tannic acid (0.321 day-1 followed by glycine, starch, lysine, sucrose and glucose (0.1004, 0.0504, 0.0486, 0.0251 and 0.0158 day-1, respectively. From theoretical calculations and oxygen and carbon concentrations we obtained the stoichiometry of the mineralization processes. Stoichiometric values varied from 0.17 (tannic acid to 2.55 (sucrose.

  13. Low energy consumption method for separating gaseous mixtures and in particular for medium purity oxygen production

    Science.gov (United States)

    Jujasz, Albert J.; Burkhart, James A.; Greenberg, Ralph

    1988-01-01

    A method for the separation of gaseous mixtures such as air and for producing medium purity oxygen, comprising compressing the gaseous mixture in a first compressor to about 3.9-4.1 atmospheres pressure, passing said compressed gaseous mixture in heat exchange relationship with sub-ambient temperature gaseous nitrogen, dividing the cooled, pressurized gaseous mixture into first and second streams, introducing the first stream into the high pressure chamber of a double rectification column, separating the gaseous mixture in the rectification column into a liquid oxygen-enriched stream and a gaseous nitrogen stream and supplying the gaseous nitrogen stream for cooling the compressed gaseous mixture, removing the liquid oxygen-enriched stream from the low pressure chamber of the rectification column and pumping the liquid, oxygen-enriched steam to a predetermined pressure, cooling the second stream, condensing the cooled second stream and evaporating the oxygen-enriched stream in an evaporator-condenser, delivering the condensed second stream to the high pressure chamber of the rectification column, and heating the oxygen-enriched stream and blending the oxygen-enriched stream with a compressed blend-air stream to the desired oxygen concentration.

  14. Myocardial Blood Volume Is Associated with Myocardial Oxygen Consumption: An Experimental Study with CMR in a Canine Model

    Science.gov (United States)

    McCommis, Kyle S.; Zhang, Haosen; Goldstein, Thomas A.; Misselwitz, Bernd; Abendschein, Dana R.; Gropler, Robert J.; Zheng, Jie

    2009-01-01

    OBJECTIVES To evaluate the feasibility of cardiovascular MR (CMR) to determine regional myocardial perfusion and O2 metabolism, and assess the role of myocardial blood volume (MBV) on oxygen supply. BACKGROUND Coronary artery disease presents as an imbalance of myocardial oxygen supply and demand. We have developed relevant CMR methods to determine the relationship of myocardial blood flow (MBF) and MBV to oxygen consumption (MVO2) during pharmacologic hyperemia. METHODS Twenty-one mongrel dogs were studied with varying stenosis severities imposed on the proximal left anterior descending (LAD) coronary artery. MBF and MBV were determined by CMR first-pass perfusion, while the oxygen extraction fraction (OEF) and MVO2 were determined by the myocardial Blood-Oxygen-Level-Dependent (BOLD) effect and Fick’s law, respectively. MR imaging was performed at rest, and during either dipyridamole-induced vasodilation or dobutamine-induced hyperemia. Regional differences in myocardial perfusion and oxygenation were then evaluated. RESULTS Dipyridamole and dobutamine both led to 145–200% increases in MBF and 50–80% increases in MBV in normal perfused myocardium. As expected, MVO2 increased more significantly with dobutamine (~175%) than dipyridamole (~40%). Coronary stenosis resulted in an attenuation of MBF, MBV, and MVO2 in both the LAD-subtended stenosis region and the left circumflex subtended remote region. Liner regression analysis showed that MBV reserve appears to be more correlated with MVO2 reserve during dobutamine stress than MBF reserve, particularly in the stenotic regions. Conversely, MBF reserve appears to be more correlated with MVO2 reserve during dipyridamole, although neither of these differences was significant. CONCLUSIONS Noninvasive evaluation of both myocardial perfusion and oxygenation by CMR facilitates direct monitoring of regional myocardial ischemia and provides a valuable tool for better understanding microvascular pathophysiology. These

  15. Changes in Whole-Body Oxygen Consumption and Skeletal Muscle Mitochondria During Linezolid-Induced Lactic Acidosis.

    Science.gov (United States)

    Protti, Alessandro; Ronchi, Dario; Bassi, Gabriele; Fortunato, Francesco; Bordoni, Andreina; Rizzuti, Tommaso; Fumagalli, Roberto

    2016-07-01

    To better clarify the pathogenesis of linezolid-induced lactic acidosis. Case report. ICU. A 64-year-old man who died with linezolid-induced lactic acidosis. Skeletal muscle was sampled at autopsy to study mitochondrial function. Lactic acidosis developed during continuous infusion of linezolid while oxygen consumption and oxygen extraction were diminishing from 172 to 52 mL/min/m and from 0.27 to 0.10, respectively. Activities of skeletal muscle respiratory chain complexes I, III, and IV, encoded by nuclear and mitochondrial DNA, were abnormally low, whereas activity of complex II, entirely encoded by nuclear DNA, was not. Protein studies confirmed stoichiometric imbalance between mitochondrial (cytochrome c oxidase subunits 1 and 2) and nuclear (succinate dehydrogenase A) DNA-encoded respiratory chain subunits. These findings were not explained by defects in mitochondrial DNA or transcription. There were no compensatory mitochondrial biogenesis (no induction of nuclear respiratory factor 1 and mitochondrial transcript factor A) or adaptive unfolded protein response (reduced concentration of heat shock proteins 60 and 70). Linezolid-induced lactic acidosis is associated with diminished global oxygen consumption and extraction. These changes reflect selective inhibition of mitochondrial protein synthesis (probably translation) with secondary mitonuclear imbalance. One novel aspect of linezolid toxicity that needs to be confirmed is blunting of reactive mitochondrial biogenesis and unfolded protein response.

  16. Effect of esmolol infusion on myocardial oxygen consumption during extubation and quality of recovery in elderly patients undergoing general anesthesia: randomized, double blinded, clinical trial

    Directory of Open Access Journals (Sweden)

    Sherif A. ELokda

    2015-04-01

    Conclusions: Esmolol is a safe, effective and well-tolerated drug that can be used in elderly patients undergoing general anesthesia to reduce the myocardial oxygen consumption and improve the quality of recovery.

  17. The effects of interval- vs. continuous exercise on excess post-exercise oxygen consumption and substrate oxidation rates in subjects with type 2 diabetes

    DEFF Research Database (Denmark)

    Karstoft, Kristian; Wallis, Gareth A.; Pedersen, Bente K.

    2016-01-01

    Background For unknown reasons, interval training often reduces body weight more than energy-expenditure matched continuous training. We compared the acute effects of time-duration and oxygen-consumption matched interval- vs. continuous exercise on excess post-exercise oxygen consumption (EPOC...... (MMTT, 450 kcal) was consumed by the subjects 45 min after completion of the intervention with blood samples taken regularly. Results Exercise interventions were successfully matched for total oxygen consumption (CW = 1641 ± 133 mL/min; IW = 1634 ± 126 mL/min, P > 0.05). EPOC was higher after IW (8......, free fatty acids and glycerol concentrations, and glycerol kinetics were increased comparably during and after IW and CW compared to CON. Conclusions Interval exercise results in greater EPOC than oxygen-consumption matched continuous exercise during a post-exercise MMTT in subjects with T2D, whereas...

  18. Local cerebral blood flow (1CBF) and oxygen consumption (1CMRO2) in evolving irreversible ischemic infarction: a study with positron tomography and oxygen-15

    International Nuclear Information System (INIS)

    Baron, J.C.; Rougemont, D.; Lebrun-Grandie, P.; Comar, D.; Bousser, M.G.; Bories, J.; Castaigne, P.; Cabanis, E.

    1982-09-01

    In 25 patients suffering from cerebral ischemia set up in the area of the internal carotid artery the local cerebral blood flow (lCBF) and local cerebral oxygen consumption (lCMRO 2 ) were measured by the method of continuous inhalation of oxygen 15-labelled gas combined with positron emission tomography. These two local parameters and their ratio, the local oxygen extraction rate (lO 2 E), were studied inside the brain region tending spontaneously towards ischemic necrosis, a zone defined by means of repeated tomodensitometric examinations. The essential facts observed are the variability of the lCBF and the lO 2 E values, from extremely low to extremely high, whereas the collapse of the lCMRO 2 is constant. Consequently this last parameter alone would be a good prognostic index, an lCMRO 2 decrease to a level below about 70% of the controlateral value indicating that the necrosis is spontaneously irreparable. These results are discussed in the light of published data

  19. Step Test: a method for evaluating maximum oxygen consumption to determine the ability kind of work among students of medical emergencies.

    Science.gov (United States)

    Heydari, Payam; Varmazyar, Sakineh; Nikpey, Ahmad; Variani, Ali Safari; Jafarvand, Mojtaba

    2017-03-01

    Maximum oxygen consumption shows the maximum oxygen rate of muscle oxygenation that is acceptable in many cases, to measure the fitness between person and the desired job. Given that medical emergencies are important, and difficult jobs in emergency situations require people with high physical ability and readiness for the job, the aim of this study was to evaluate the maximum oxygen consumption, to determine the ability of work type among students of medical emergencies in Qazvin in 2016. This study was a descriptive - analytical, and in cross-sectional type conducted among 36 volunteer students of medical emergencies in Qazvin in 2016. After necessary coordination for the implementation of the study, participants completed health questionnaires and demographic characteristics and then the participants were evaluated with step tests of American College of Sport Medicine (ACSM). Data analysis was done by SPSS version 18 and U-Mann-Whitney tests, Kruskal-Wallis and Pearson correlation coefficient. Average of maximum oxygen consumption of the participants was estimated 3.15±0.50 liters per minute. 91.7% of medical emergencies students were selected as appropriate in terms of maximum oxygen consumption and thus had the ability to do heavy and too heavy work. Average of maximum oxygen consumption evaluated by the U-Mann-Whitney test and Kruskal-Wallis, had significant relationship with age (p<0.05) and weight groups (p<0.001). There was a significant positive correlation between maximum oxygen consumption with weight and body mass index (p<0.001). The results of this study showed that demographic variables of weight and body mass index are the factors influencing the determination of maximum oxygen consumption, as most of the students had the ability to do heavy, and too heavy work. Therefore, people with ability to do average work are not suitable for medical emergency tasks.

  20. Relationship between level of forage intake, blood flow and oxygen consumption by splanchnic tissues of sheep fed a tropical grass forage.

    Science.gov (United States)

    Hentz, F; Kozloski, G V; Zeni, D; Brun, M V; Stefanello, S

    2017-02-01

    Four Polwarth castrated male sheep (42 ± 4.4 kg live weight (LW) surgically implanted with chronic indwelling catheters into the mesenteric, portal and hepatic veins, housed in metabolism cages and offered Cynodon sp. hay at rates (g of dry matter (DM)/kg LW) of 7, 14, 21 or ad libitum, were used in a 4 × 4 Latin square experiment to evaluate the effect of the level of forage intake on blood flow and oxygen consumption by the portal-drained viscera (PDV), liver and total splanchnic tissues (ST). The portal blood flow and the oxygen consumption by PDV linearly increased at increased organic matter (OM) intake. No effect of level of OM intake was obtained for the hepatic artery blood flow and oxygen consumption by liver. As a consequence, the level of OM intake only tended to directly affect hepatic blood flow and oxygen consumption by total ST. Oxygen consumption was linearly and positively related to blood flow across PDV, liver and total ST. The heat production by PDV and total ST, as proportion of metabolizable energy (ME) intake, decreased curvilinearly at increased ME intake. In conclusion, the oxygen consumption by PDV, but not by liver, was directly related to the level of forage intake by sheep. Moreover, when ingested at levels below maintenance, most of ME was spent as heat produced by ST. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

  1. Noninvasive in vivo optical characterization of blood flow and oxygen consumption in the superficial plexus of skin

    Science.gov (United States)

    Liasi, Faezeh Talebi; Samatham, Ravikant; Jacques, Steven L.

    2017-11-01

    Assessing the metabolic activity of a tissue, whether normal, damaged, aged, or pathologic, is useful for diagnosis and evaluating the effects of drugs. This report describes a handheld optical fiber probe that contacts the skin, applies pressure to blanch the superficial vascular plexus of the skin, then releases the pressure to allow refill of the plexus. The optical probe uses white light spectroscopy to record the time dynamics of blanching and refilling. The magnitude and dynamics of changes in blood content and hemoglobin oxygen saturation yield an estimate of the oxygen consumption rate (OCR) in units of attomoles per cell per second. The average value of OCR on nine forearm sites on five subjects was 10±5 (amol/cell/s). This low-cost, portable, rapid, noninvasive optical probe can characterize the OCR of a skin site to assess the metabolic activity of the epidermis or a superficial lesion.

  2. Impact of Increasing Levels of Oxygen Consumption on the Evolution of Color, Phenolic, and Volatile Compounds of Nebbiolo Wines

    Directory of Open Access Journals (Sweden)

    Maurizio Petrozziello

    2018-04-01

    Full Text Available Since the end of the last century, many works have been carried out to verify the effect of controlled oxygen intake on the chemical and organoleptic characteristics of red wines. In spite of the large number of studies on this subject, oxygen remains a cutting-edge research topic in oenology. Oxygen consumption leads to complex and not univocal changes in wine composition, sometimes positive such as color stabilization, softening of mouthfeel, increase of aroma complexity. However, the variability of these effects, which depend both on the oxygenation conditions and the composition of the wine, require more efforts in this research field to effectively manage wine oxygen exposure. The present study is focused on the evolution of the chemical composition of four different Nebbiolo wines, each of them added with 4 different doses of oxygen (7, 14, 21, and 28 mg/L total intake during the first month of storage. In this perspective, the evolution over time of wine color and polyphenols was studied. Acetaldehyde, glyceraldehyde and glyoxylic acid were quantified by HPLC. These compounds can play a role in wine aging creating condensed colored and stable products involving anthocyanins with or without tannins. Moreover, some volatile aldehydes correlated with oxidized olfactory notes, including methional and (E-2-alkenals, have been quantified by GC-MS. Overall, during storage a decrease of color intensity, total and free anthocyanins and an increase in polymeric pigments (in particular the contribution to the red color of pigments not-bleachable by SO2 or dTAT% and some minor aldehydes was observed. Nevertheless, the differences in color parameters between the samples with different doses of oxygen were modest. These evidences were in contrast with an evident and detectable increase of free acetaldehyde content at increasing doses of oxygen measured after 60 days of storage. The effect of oxygen on color and production of SO2 non-bleachable pigments

  3. Impact of Increasing Levels of Oxygen Consumption on the Evolution of Color, Phenolic, and Volatile Compounds of Nebbiolo Wines.

    Science.gov (United States)

    Petrozziello, Maurizio; Torchio, Fabrizio; Piano, Federico; Giacosa, Simone; Ugliano, Maurizio; Bosso, Antonella; Rolle, Luca

    2018-01-01

    Since the end of the last century, many works have been carried out to verify the effect of controlled oxygen intake on the chemical and organoleptic characteristics of red wines. In spite of the large number of studies on this subject, oxygen remains a cutting-edge research topic in oenology. Oxygen consumption leads to complex and not univocal changes in wine composition, sometimes positive such as color stabilization, softening of mouthfeel, increase of aroma complexity. However, the variability of these effects, which depend both on the oxygenation conditions and the composition of the wine, require more efforts in this research field to effectively manage wine oxygen exposure. The present study is focused on the evolution of the chemical composition of four different Nebbiolo wines, each of them added with 4 different doses of oxygen (7, 14, 21, and 28 mg/L total intake) during the first month of storage. In this perspective, the evolution over time of wine color and polyphenols was studied. Acetaldehyde, glyceraldehyde and glyoxylic acid were quantified by HPLC. These compounds can play a role in wine aging creating condensed colored and stable products involving anthocyanins with or without tannins. Moreover, some volatile aldehydes correlated with oxidized olfactory notes, including methional and (E)-2-alkenals, have been quantified by GC-MS. Overall, during storage a decrease of color intensity, total and free anthocyanins and an increase in polymeric pigments (in particular the contribution to the red color of pigments not-bleachable by SO 2 or dTAT%) and some minor aldehydes was observed. Nevertheless, the differences in color parameters between the samples with different doses of oxygen were modest. These evidences were in contrast with an evident and detectable increase of free acetaldehyde content at increasing doses of oxygen measured after 60 days of storage. The effect of oxygen on color and production of SO 2 non-bleachable pigments during aging

  4. Impact of Increasing Levels of Oxygen Consumption on the Evolution of Color, Phenolic, and Volatile Compounds of Nebbiolo Wines

    Science.gov (United States)

    Petrozziello, Maurizio; Torchio, Fabrizio; Piano, Federico; Giacosa, Simone; Ugliano, Maurizio; Bosso, Antonella; Rolle, Luca

    2018-01-01

    Since the end of the last century, many works have been carried out to verify the effect of controlled oxygen intake on the chemical and organoleptic characteristics of red wines. In spite of the large number of studies on this subject, oxygen remains a cutting-edge research topic in oenology. Oxygen consumption leads to complex and not univocal changes in wine composition, sometimes positive such as color stabilization, softening of mouthfeel, increase of aroma complexity. However, the variability of these effects, which depend both on the oxygenation conditions and the composition of the wine, require more efforts in this research field to effectively manage wine oxygen exposure. The present study is focused on the evolution of the chemical composition of four different Nebbiolo wines, each of them added with 4 different doses of oxygen (7, 14, 21, and 28 mg/L total intake) during the first month of storage. In this perspective, the evolution over time of wine color and polyphenols was studied. Acetaldehyde, glyceraldehyde and glyoxylic acid were quantified by HPLC. These compounds can play a role in wine aging creating condensed colored and stable products involving anthocyanins with or without tannins. Moreover, some volatile aldehydes correlated with oxidized olfactory notes, including methional and (E)-2-alkenals, have been quantified by GC-MS. Overall, during storage a decrease of color intensity, total and free anthocyanins and an increase in polymeric pigments (in particular the contribution to the red color of pigments not-bleachable by SO2 or dTAT%) and some minor aldehydes was observed. Nevertheless, the differences in color parameters between the samples with different doses of oxygen were modest. These evidences were in contrast with an evident and detectable increase of free acetaldehyde content at increasing doses of oxygen measured after 60 days of storage. The effect of oxygen on color and production of SO2 non-bleachable pigments during aging

  5. Effects of Cortical Spreading Depression on Synaptic Activity, Blood Flow and Oxygen Consumption in Rat Cerebral Cortex

    DEFF Research Database (Denmark)

    Hansen, Henning Piilgaard

    2010-01-01

    As the title of this thesis indicates I have during my PhD studied the effects of cortical spreading depression (CSD) on synaptic activity, blood flow and oxygen consumption in rat cerebral cortex. This was performed in vivo using an open cranial window approach in anesthetized rats. I applied...... parameters of the whisker/infraorbital nerve etwork (IO) targeting the same cortical area. We tested the hypothesis that the relation between increases in CBF and CMRO2 evoked by stimulation and synaptic activity differed for the two activated networks and that activation of two distinct networks activate...

  6. Low Cerebral Oxygen Consumption and Blood Flow in Patients With Cirrhosis and an Acute Episode of Hepatic Encephalopathy

    DEFF Research Database (Denmark)

    Iversen, Peter; Bak, Lasse Kristoffer; Waagepetersen, Helle Sønderby

    2009-01-01

    (15)O-water PET in 6 patients with liver cirrhosis and an acute episode of overt HE, 6 cirrhotic patients without HE, and 7 healthy subjects. RESULTS: Neither whole-brain CMRO(2) nor CBF differed significantly between cirrhotic patients without HE and healthy subjects, but were both significantly...... that the reductions in CMRO(2) and CBF in patients with HE were essentially generalized throughout the brain. CONCLUSIONS: The observations imply that reduced cerebral oxygen consumption and blood flow in cirrhotic patients with an acute episode of overt HE are associated with HE and not cirrhosis as such...

  7. Kinetics of oxygen consumption after a single flash of light in photoreceptors of the drone (Apis mellifera)

    OpenAIRE

    1982-01-01

    The time course of the rate of oxygen consumption (QO2) after a single flash of light has been measured in 300-micrometers slices of drone retina at 22 degrees C. To measure delta QO2(t), the change in QO2 from its level in darkness, the transients of the partial pressure of O2 (PO2) were recorded with O2 microelectrodes simultaneously in two sites in the slice and delta QO2 was calculated by a computer using Fourier transforms. After a 40-ms flash of intense light, delta QO2, reached a peak ...

  8. Effects of Low-Permeability Layers in the Hyporheic Zone on Oxygen Consumption Under Losing and Gaining Groundwater Flow Conditions

    Science.gov (United States)

    Arnon, S.; Krause, S.; Gomez-Velez, J. D.; De Falco, N.

    2017-12-01

    Recent studies at the watershed scale have demonstrated the dominant role that river bedforms play in driving hyporheic exchange and constraining biogeochemical processes along river corridors. At the reach and bedform scales, modeling studies have shown that sediment heterogeneity significantly modifies hyporheic flow patterns within bedforms, resulting in spatially heterogeneous biogeochemical processes. In this work, we summarize a series of flume experiments to evaluate the effect that low-permeability layers, representative of structural heterogeneity, have on hyporheic exchange and oxygen consumption in sandy streambeds. In this case, we systematically changed the geometry of the heterogeneities, the surface channel flow driving the exchange, and groundwater fluxes (gaining/losing) modulating the exchange. The flume was packed with natural sediments, which were amended with compost to minimize carbon limitations. Structural heterogeneities were represented by continuous and discontinuous layers of clay material. Flow patterns were studied using dye imaging through the side walls. Oxygen distribution in the streambed was measured using planar optodes. The experimental observations revealed that the clay layer had a significant effect on flow patterns and oxygen distribution in the streambed under neutral and losing conditions. Under gaining conditions, the aerobic zone was limited to the upper sections of the bedform and thus was less influenced by the clay layers that were located at a depth of 1-3 cm below the water-sediment interface. We are currently analyzing the results with a numerical flow and transport model to quantify the reactions rates under the different flow conditions and spatial sediment structures. Our preliminary results enable us to show the importance of the coupling between flow conditions, local heterogeneity within the streambed and oxygen consumption along bed forms and are expected to improve our ability to model the effect of stream

  9. The effect of exercise intensity and excess postexercise oxygen consumption on postprandial blood lipids in physically inactive men.

    Science.gov (United States)

    Littlefield, Laurel A; Papadakis, Zacharias; Rogers, Katie M; Moncada-Jiménez, José; Taylor, J Kyle; Grandjean, Peter W

    2017-09-01

    Reductions in postprandial lipemia have been observed following aerobic exercise of sufficient energy expenditure. Increased excess postexercise oxygen consumption (EPOC) has been documented when comparing high- versus low-intensity exercise. The contribution of EPOC energy expenditure to alterations in postprandial lipemia has not been determined. The purpose of this study was to evaluate the effects of low- and high-intensity exercise on postprandial lipemia in healthy, sedentary, overweight and obese men (age, 43 ± 10 years; peak oxygen consumption, 31.1 ± 7.5 mL·kg -1 ·min -1 ; body mass index, 31.8 ± 4.5 kg/m 2 ) and to determine the contribution of EPOC to reductions in postprandial lipemia. Participants completed 4 conditions: nonexercise control, low-intensity exercise at 40%-50% oxygen uptake reserve (LI), high-intensity exercise at 70%-80% oxygen uptake reserve (HI), and HI plus EPOC re-feeding (HI+EERM), where the difference in EPOC energy expenditure between LI and HI was re-fed in the form of a sports nutrition bar (Premier Nutrition Corp., Emeryville, Calif., USA). Two hours following exercise participants ingested a high-fat (1010 kcals, 99 g sat fat) test meal. Blood samples were obtained before exercise, before the test meal, and at 2, 4, and 6 h postprandially. Triglyceride incremental area under the curve was significantly reduced following LI, HI, and HI+EERM when compared with nonexercise control (p exercise conditions (p > 0.05). In conclusions, prior LI and HI exercise equally attenuated postprandial triglyceride responses to the test meal. The extra energy expended during EPOC does not contribute significantly to exercise energy expenditure or to reductions in postprandial lipemia in overweight men.

  10. Direct measurements of the light dependence of gross photosynthesis and oxygen consumption in the ocean

    Science.gov (United States)

    Bailleul, B.; Park, J.; Brown, C. M.; Bidle, K. D.; Lee, S.; Falkowski, P. G.

    2016-02-01

    For decades, a lack of understanding of how respiration is influenced by light has been stymying our ability to quantitatively analyze how phytoplankton allocate carbon in situ and the biological mechanisms that participate to the fate of blooms. Using membrane inlet mass spectrometry (MIMS), the light dependencies of gross photosynthesis and oxygen uptake rates were measured during the bloom demises of two prymnesiophytes, in two open ocean regions. In the North Atlantic, dominated by Emiliania huxleyi, respiration was independent of irradiance and was higher than the gross photosynthetic rate at all irradiances. In the Amundsen Sea (Antarctica), dominated by Phaeocystis antarctica, the situation was very different. Dark respiration was one order of magnitude lower than the maximal gross photosynthetic rate. ut the oxygen uptake rate increased by 10 fold at surface irradiances, where it becomes higher than gross photosynthesis. Our results suggest that the light dependence of oxygen uptake in P. antarctica has two sources: one is independent of photosynthesis, and is possibly associated with the photo-reduction of O2 mediated by dissolved organic matter; the second reflects the activity of an oxidase fueled in the light with photosynthetic electron flow. Interestingly, these dramatic light-dependent changes in oxygen uptake were not reproduced in nutrient-replete P. antarctica cultures, in the laboratory. Our measurements highlight the importance of improving our understanding of oxygen consuming reactions in the euphotic zone, which is critical to investigating the physiology of phytoplankton and tracing the fate of phytoplankton blooms.

  11. Cold exposure enhances fat utilization but not non-esterified fatty acids, glycerol or catecholamines availability during submaximal walking and running

    Directory of Open Access Journals (Sweden)

    Dominique Daniel Gagnon

    2013-05-01

    Full Text Available Cold exposure modulates the use of carbohydrates and fat during exercise. This phenomenon has mostly been observed in controlled cycling studies, but not during walking and running when core temperature and oxygen consumption are controlled, as both may alter energy metabolism. This study aimed at examining energy substrate availability and utilization during walking and running in the cold when core temperature and oxygen consumption are maintained. Ten lightly clothed male subjects walked or ran for 60-min, at 50% and 70% of maximal oxygen consumption, respectively, in a climatic chamber set at 0°C or 22°C. Thermal, cardiovascular, and oxidative responses were measured every 15-min during exercise. Blood samples for serum non-esterified fatty acids, glycerol, glucose, beta-hydroxybutyrate, plasma catecholamines, and serum lipids were collected immediately prior, and at 30- and 60-min of exercise. Skin temperature strongly decreased while core temperature did not change during cold trials. Heart rate was also lower in cold trials. A rise in fat utilization in the cold was seen through lower respiratory quotient (-0.03 ± 0.02, greater fat oxidation (+0.14 ± 0.13 g•min-1 and contribution of fat to total energy expenditure (+1.62 ± 1.99 kcal•min-1. No differences from cold exposure were observed in blood parameters. During submaximal walking and running, a greater reliance on derived fat sources occurs in the cold, despite the absence of concurrent alterations in non-esterified fatty acids, glycerol, or catecholamine concentrations. This disparity may suggest a greater reliance on intra-muscular energy sources such as triglycerides during both walking and running.

  12. Differential contributions of ankle plantarflexors during submaximal isometric muscle action

    DEFF Research Database (Denmark)

    Masood, Tahir; Bojsen-Møller, Jens; Kalliokoski, Kari K

    2014-01-01

    The objective of this study was to investigate the relative contributions of superficial and deep ankle plantarflexors during repetitive submaximal isometric contractions using surface electromyography (SEMG) and positron emission tomography (PET). Myoelectric signals were obtained from twelve...

  13. Effective oxygen-consumption rates in fermentation broths with filamentous organisms

    Energy Technology Data Exchange (ETDEWEB)

    Reuss, M; Bajpai, R K; Berke, W

    1982-01-01

    The concept of coupling molecular diffusion and reaction has been applied in the past to various biological systems with clearly defined geometrical properties like pellets and immobilised enzymes/microorganisms. This paper investigates the use of the same principle to characterise the diffusional limitation in suspensions of filamentous microorganisms. Experimental results of oxygen-uptake measurements from Aspergillus niger fermentations in a 50 cu.dm turbine-agitated fermentor are presented with theoretical predictions of coupled diffusion and oxygen kinetics. Results are discussed on the basis of turbulence theory so that the mycelial broth can be structured in hypothetical spherical elements. Consideration of local energy-dissipation rates in the impeller region provides reasonable explanation of the strong influence of the impeller/tank diameter ratio on the effective oxygen-uptake rate at a given power input. (Refs. 18).

  14. Oxygen Consumption and Acoustic Activity of Adult Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae: Bruchinae) during Hermetic Storage.

    Science.gov (United States)

    Njoroge, Anastasia W; Mankin, Richard W; Smith, Bradley W; Baributsa, Dieudonne

    2018-04-20

    Acoustic monitoring was applied to consider hermetic exposure durations and oxygen levels required to stop adult Callosobruchus maculatus activity and economic damage on cowpea. A 15-d study was conducted with six treatments of 25, 50, and 100 C. maculatus adults in 500 and 1000 mL jars using acoustic probes inserted through stoppers sealing the jars. Acoustic activity as a result of locomotion, mating, and egg-laying was measured by identifying sound impulses with frequency spectra representative of known insect sounds, and counting trains (bursts) of impulses separated by intervals of <200 ms, that typically are produced only by insects. By the end of the first week of storage in all treatments, oxygen levels declined to levels below 4%, which has been demonstrated to cause mortality in previous studies. Concomitantly, insect sound burst rates dropped below an acoustic detection threshold of 0.02 bursts s −1 , indicating that the insects had ceased feeding. Statistically significant relationships were obtained between two different measures of the acoustic activity and the residual oxygen level. Based on the experimental results, a simple equation can be used to estimate the time needed for oxygen to decline to levels that limit insect feeding damage and thus grain losses in hermetic storage containers of different insect population levels and various volumes.

  15. Using carbon emissions and oxygen consumption to estimate energetics parameters of cattle consuming forages

    Science.gov (United States)

    To evaluate newer indirect calorimetry system to quantify energetic parameters, 8 cross-bred beef steers (initial BW = 241 ± 4.10 kg) were used in a 77-d experiment to examine energetics parameters calculated from carbon dioxide (CO2), methane (CH4), and oxygen (O2) fluxes. Steers were individually ...

  16. Sodium cyanide induced alteration in the whole animal oxygen consumption and behavioural pattern of freshwater fish Labeo rohita.

    Science.gov (United States)

    David, Muniswamy; Sangeetha, Jeyabalan; Harish, Etigemane R

    2015-03-01

    Sodium cyanide is a common environmental pollutant which is mainly used in many industries such as mining, electroplating, steel manufacturing, pharmaceutical production and other specialized applications including dyes and agricultural products. It enters aquatic environment through effluents from these industries. Static renewal bioassay test has been conducted to determine LC, of sodium cyanide on indigenous freshwater carp, Labeo rohita. The behavioural pattern and oxygen consumption were observed in fish at both lethal and sub lethal concentrations. Labeo rohita in toxic media exhibited irregular and erratic swimming movements, hyper excitability, loss of equilibrium and shrinking to the bottom, which may be due to inhibition of cytochrome C oxidase activity and decreased blood pH. The combination of cytotoxic hypoxia with lactate acidosis depresses the central nervous system resulting in respiratory arrest and death. Decrease in oxygen consumption was observed at both lethal and sub lethal concentrations of sodium cyanide. Mortality was insignificant at sub lethal concentration test when fishes were found under stress. Consequence of impaired oxidative metabolism and elevated physiological response by fish against sodium cyanide stress showed alteration in respiratory rate.

  17. Effects of a whole-body spandex garment on rectal temperature and oxygen consumption in healthy dogs.

    Science.gov (United States)

    Reimer, S Brent; Schulz, Kurt S; Mason, David R; Jones, James H

    2004-01-01

    To determine whether a full-body spandex garment would alter rectal temperatures of healthy dogs at rest in cool and warm environments. Prospective study. 10 healthy dogs. Each dog was evaluated at a low (20 degrees to 25 degrees C [68 degrees to 77 degrees F]) or high (30 degrees to 35 degrees C [86 degrees to 95 degrees F]) ambient temperature while wearing or not wearing a commercially available whole-body spandex garment designed for dogs. Oxygen consumption was measured by placing dogs in a flow-through indirect calorimeter for 90 to 120 minutes. Rectal temperature was measured before dogs were placed in the calorimeter and after they were removed. Rectal temperature increased significantly more at the higher ambient temperature than at the lower temperature and when dogs were not wearing the garment than when they were wearing it. The specific rate of oxygen consumption was significantly higher at the lower ambient temperature than at the higher temperature. Results suggest that wearing a snug spandex body garment does not increase the possibility that dogs will overheat while in moderate ambient temperatures. Instead, wearing such a garment may enable dogs to better maintain body temperature during moderate heat loading. These results suggest that such garments might be used for purposes such as wound or suture protection without causing dogs to overheat.

  18. Measurement of Diaphragmatic Blood Flow and Oxygen Consumption in the Dog by the Kety-Schmidt Technique

    Science.gov (United States)

    Rochester, Dudley F.

    1974-01-01

    To assess energy expenditure of the diaphragm directly, a method was devised for percutaneous catheterization of the left inferior phrenic vein in dogs. Necropsy studies, including retrograde injection of india ink and measurement of radioactivity in diaphragmatic muscle strips, suggested that the territory drained by the inferior phrenic vein was uniformly perfused, and that there were no major anastomoses between this bed and adjacent ones. Diaphragmatic blood flow (˙Q di) was calculated from the integrated diaphragmatic arteriovenous difference of 85Kr by the Kety-Schmidt technique. Diaphragmatic oxygen consumption (˙Vo2 di) was determined as the product of ˙Q di and the diaphragmatic arteriovenous oxygen content difference [(A-V)O2 di]. When lightly anesthetized dogs breathed quietly, ˙Q di was 22±SD 6 ml/min/100 g, (A-V)O2 di was 6.1±SD 2.5 ml/100 ml, and ˙VO2 di averaged 1.2±SD 0.3 ml/min/100 g. This represented 1.0±SD 0.2% of total body oxygen consumption. ˙VO2 di remained relatively constant during quiet breathing, whereas ˙Q di varied directly with cardiac output and reciprocally with (A-V)O2 di. The oxygen consumption of the noncontracting diaphragm was 60±SD 20% of the level measured during quiet breathing. The energy expended by the diaphragm to support simple hyperventilation was small. A 100% increase in minute ventilation, induced by inhalation of 5% CO2 in 21% or 14% O2, increased ˙Q di 13%, (A-V)O2 di 19%, and ˙VO2 di 40%. The diaphragm consumed 0.13±SD 0.09 ml O2 for each additional liter of ventilation. In four dogs, pneumonia appeared to increase ˙VO2 both by increasing minute ventilation and by increasing the energy cost per liter of ventilation. PMID:4825221

  19. Oxygen consumption of a pneumatically controlled ventilator in a field anesthesia machine.

    Science.gov (United States)

    Szpisjak, Dale F; Javernick, Elizabeth N; Kyle, Richard R; Austin, Paul N

    2008-12-01

    Field anesthesia machines (FAM) have been developed for remote locations where reliable supplies of compressed medical gases or electricity may be absent. In place of electricity, pneumatically controlled ventilators use compressed gas to power timing circuitry and actuate valves. We sought to determine the total O(2) consumption and ventilator gas consumption (drive gas [DG] plus pneumatic control [PC] gas) of a FAM's pneumatically controlled ventilator in mechanical models of high (HC) and low (LC) total thoracic compliance. The amount of total O(2) consumed by the Magellan-2200 (Oceanic Medical Products, Atchison, KS) FAM with pneumatically controlled ventilator was calculated using the ideal gas law and the measured mass of O(2) consumed from E cylinders. DG to the bellows canister assembly was measured with the Wright Respirometer Mk 8 (Ferraris Respiratory Europe, Hertford, UK). PC gas consumption was calculated by subtracting DG and fresh gas flow (FGF) from the total O(2) consumed from the E cylinder. The delivered tidal volume (V(T)) was measured with a pneumotach (Hans Rudolph, KS City, MO). Three different V(T) were tested (500, 750, and 1000 mL) with two lung models (HC and LC) using the Vent Aid Training Test Lung (MI Instruments, Grand Rapids, MI). Respiratory variables included an I:E of 1:2, FGF of 1 L/min, and respiratory rate of 10 breaths/min. Total O(2) consumption was directly proportional to V(T) and inversely proportional to compliance. The smallest total O(2) consumption rate (including FGF) was 9.3 +/- 0.4 L/min in the HC-500 model and the largest was 15.9 +/- 0.5 L/min in the LC-1000 model (P < 0.001). The mean PC circuitry consumption was 3.9 +/- 0.24 L/min or 390 mL +/- 24 mL/breath. To prepare for loss of central DG supply, patient safety will be improved by estimating cylinder duration for low total thoracic compliance. Using data from the smaller compliance and greatest V(T) model (LC-1000), a full O(2) E cylinder would be depleted in

  20. Ketosis After Cardiopulmonary Bypass in Children Is Associated With an Inadequate Balance Between Oxygen Transport and Consumption.

    Science.gov (United States)

    Klee, Philippe; Arni, Delphine; Saudan, Sonja; Schwitzgebel, Valérie M; Sharma, Ruchika; Karam, Oliver; Rimensberger, Peter C

    2016-09-01

    Hyperglycemia after cardiac surgery and cardiopulmonary bypass in children has been associated with worse outcome; however, causality has never been proven. Furthermore, the benefit of tight glycemic control is inconsistent. The purpose of this study was to describe the metabolic constellation of children before, during, and after cardiopulmonary bypass, in order to identify a subset of patients that might benefit from insulin treatment. Prospective observational study, in which insulin treatment was initiated when postoperative blood glucose levels were more than 12 mmol/L (216 mg/dL). Tertiary PICU. Ninety-six patients 6 months to 16 years old undergoing cardiac surgery with cardiopulmonary bypass. None. Metabolic tests were performed before anesthesia, at the end of cardiopulmonary bypass, at PICU admission, and 4 and 12 hours after PICU admission, as well as 4 hours after initiation of insulin treatment. Ketosis was present in 17.9% patients at the end of cardiopulmonary bypass and in 31.2% at PICU admission. Young age was an independent risk factor for this condition. Ketosis at PICU admission was an independent risk factor for an increased difference between arterial and venous oxygen saturation. Four hours after admission (p = 0.05). Insulin corrected ketosis within 4 hours. In this study, we found a high prevalence of ketosis at PICU admission, especially in young children. This was independently associated with an imbalance between oxygen transport and consumption and was corrected by insulin. These results set the basis for future randomized controlled trials, to test whether this subgroup of patients might benefit from increased glucose intake and insulin during surgery to avoid ketosis, as improving oxygen transport and consumption might improve patient outcome.

  1. Persistent increase in oxygen consumption and impaired neurovascular coupling after spreading depression in rat neocortex

    DEFF Research Database (Denmark)

    Hansen, Henning Piilgaard; Lauritzen, Martin

    2009-01-01

    trauma. Here we tested the hypothesis that single episodes of CSD induced acute hypoxia, and prolonged impairment of neurovascular and neurometabolic coupling. Cortical spreading depression was induced in rat frontal cortex, whereas cortical electrical activity and local field potentials (LFPs) were......Cortical spreading depression (CSD) is associated with a dramatic failure of brain ion homeostasis and increased energy metabolism. There is strong clinical and experimental evidence to suggest that CSD is the mechanism of migraine, and involved in progressive neuronal injury in stroke and head...... recorded by glass microelectrodes, cerebral blood flow (CBF) by laser-Doppler flowmetry, and tissue oxygen tension (tpO(2)) with polarographic microelectrodes. Cortical spreading depression increased cerebral metabolic rate of oxygen (CMRO(2)) by 71%+/-6.7% and CBF by 238%+/-48.1% for 1 to 2 mins...

  2. Method for the determination of oxygen consumption rates and diffusion coefficients in multicellular spheroids

    OpenAIRE

    Mueller-Klieser, W.

    1984-01-01

    A method has been developed for the quantitative evaluation of oxygen tension (PO2) distributions in multicellular spheroids measured with O2-sensitive microelectrodes. The experimental data showed that multicellular tumor spheroids in stirred growth media were characterized by a diffusion-depleted zone surrounding the spheroids. This zone was elicited by an unstirred layer of medium next to the spheroid leading to a continuous decrease in the PO2 values from the bulk medium towards the spher...

  3. The effects of lead, water hardness and pH on oxygen consumption ...

    African Journals Online (AJOL)

    Closed system respirometry was performed on captive juvenile Tilapia sparrmanii exposed for 96 hours to a range of Pb-acetate concentrations in hard and soft water to determine the effect of Pb in relation to water hardness and pH. For hard and soft water with a pH above 7.51 no change in the resting specific oxygen ...

  4. Simultaneously Occurring Elevated Metabolic States Expose Constraints in Maximal Levels of Oxygen Consumption in the Oviparous Snake Lamprophis fuliginosus.

    Science.gov (United States)

    Jackson, Alexander Garrett Schavran; Leu, Szu-Yun; Hicks, James W

    African house snakes (Lamprophis fuliginosus) were used to compare the metabolic increments associated with reproduction, digestion, and activity both individually and when combined simultaneously. Rates of oxygen consumption ([Formula: see text]) and carbon dioxide production ([Formula: see text]) were measured in adult female (nonreproductive and reproductive) and adult male snakes during rest, digestion, activity while fasting, and postprandial activity. We also compared the endurance time (i.e., time to exhaustion) during activity while fasting and postprandial activity in males and females. For nonreproductive females and males, our results indicate that the metabolic increments of digestion (∼3-6-fold) and activity while fasting (∼6-10-fold) did not interact in an additive fashion; instead, the aerobic scope associated with postprandial activity was 40%-50% lower, and animals reached exhaustion up to 11 min sooner. During reproduction, there was no change in digestive [Formula: see text], but aerobic scope for activity while fasting was 30% lower than nonreproductive values. The prioritization pattern of oxygen delivery exhibited by L. fuliginosus during postprandial activity (in both males and females) and for activity while fasting (in reproductive females) was more constrained than predicted (i.e., instead of unchanged [Formula: see text], peak values were 30%-40% lower). Overall, our results indicate that L. fuliginosus's cardiopulmonary system's capacity for oxygen delivery was not sufficient to maintain the metabolic increments associated with reproduction, digestion, and activity simultaneously without limiting aerobic scope and/or activity performance.

  5. CELL RESPIRATION STUDIES : II. A COMPARATIVE STUDY OF THE OXYGEN CONSUMPTION OF BLOOD FROM NORMAL INDIVIDUALS AND PATIENTS WITH INCREASED LEUCOCYTE COUNTS (SEPSIS; CHRONIC MYELOGENOUS LEUCEMIA).

    Science.gov (United States)

    Daland, G A; Isaacs, R

    1927-06-30

    1. The oxygen consumption of blood of normal individuals, when the hemoglobin is saturated with oxygen, is practically zero within the limits of experimental error of the microspirometer used. 2. The oxygen consumed in a microspirometer by the blood of patients with chronic myelogenous leucemia with a high white blood cell count, and of one with leucocytosis from sepsis, was proportional to the number of adult polymorphonuclear neutrophils in the blood. 3. No correlation could be made between the rate of oxygen absorption and the total number of white blood cells in the blood, or the total number of immature cells, or the number of red blood cells, or the amount of oxyhemoglobin. 4. The blood of patients with chronic myelogenous leucemia continued to use oxygen in the microspirometer longer than that of normal individuals, and the hemoglobin, in the leucemic bloods, became desaturated even though exposed to air. 5. In blood in which the bulk. of the cells were immature and the mature cells few, the oxygen consumption was lower than in blood in which the mature cells predominated. The rate of oxygen consumption of the immature cells was relatively low as compared to the mature. 6. The slower rate of oxygen absorption by the immature leucocytes in chronic myelogenous leucemia as compared to the mature cells, places them, in accord with Warburg's reports, in the class of the malignant tissues in this respect rather than in the group of young or embryonic cells.

  6. The responses of photosynthesis and oxygen consumption to short-term changes in temperature and irradiance in a cyanobacterial mat (Ebro Delta, Spain)

    DEFF Research Database (Denmark)

    Epping, E.H.G.; Kühl, Michael

    2000-01-01

    We have evaluated the effects of short-term changes in incident irradiance and temperature on oxygenic photosynthesis and oxygen consumption in a hypersaline cyanobacterial mat from the Ebro Delta, Spain, in which Microcoleus chthonoplastes was the dominant phototrophic organism. The mat was incu......We have evaluated the effects of short-term changes in incident irradiance and temperature on oxygenic photosynthesis and oxygen consumption in a hypersaline cyanobacterial mat from the Ebro Delta, Spain, in which Microcoleus chthonoplastes was the dominant phototrophic organism. The mat...... was incubated in the laboratory at 15, 20, 25 and 308C at incident irradiances ranging from 0 to 1000 mmol photons m22 s21. Oxygen microsensors were used to measure steady-state oxygen profiles and the rates of gross photosynthesis, which allowed the calculation of areal gross photosynthesis, areal net oxygen...... production, and oxygen consumption in the aphotic layer of the mat. The lowest surface irradiance that resulted in detectable rates of gross photosynthesis increased with increasing temperature from 50 mmol photons m22 s21 at 158C to 500 mmol photons m22 s21 at 308C. These threshold irradiances were also...

  7. Enhanced oxygen consumption in Herbaspirillum seropedicae fnr mutants leads to increased NifA mediated transcriptional activation.

    Science.gov (United States)

    Batista, Marcelo Bueno; Wassem, Roseli; Pedrosa, Fábio de Oliveira; de Souza, Emanuel Maltempi; Dixon, Ray; Monteiro, Rose Adele

    2015-05-07

    Orthologous proteins of the Crp/Fnr family have been previously implicated in controlling expression and/or activity of the NifA transcriptional activator in some diazotrophs. This study aimed to address the role of three Fnr-like proteins from H. seropedicae SmR1 in controlling NifA activity and consequent NifA-mediated transcription activation. The activity of NifA-dependent transcriptional fusions (nifA::lacZ and nifB::lacZ) was analysed in a series of H. seropedicae fnr deletion mutant backgrounds. We found that combined deletions in both the fnr1 and fnr3 genes lead to higher expression of both the nifA and nifB genes and also an increased level of nifH transcripts. Expression profiles of nifB under different oxygen concentrations, together with oxygen consumption measurements suggest that the triple fnr mutant has higher respiratory activity when compared to the wild type, which we believe to be responsible for greater stability of the oxygen sensitive NifA protein. This conclusion was further substantiated by measuring the levels of NifA protein and its activity in fnr deletion strains in comparison with the wild-type. Fnr proteins are indirectly involved in controlling the activity of NifA in H. seropedicae, probably as a consequence of their influence on respiratory activity in relation to oxygen availability. Additionally we can suggest that there is some redundancy in the physiological function of the three Fnr paralogs in this organism, since altered respiration and effects on NifA activity are only observed in deletion strains lacking both fnr1 and fnr3.

  8. Oxygen Consumption and Usage During Physical Exercise: The Balance Between Oxidative Stress and ROS-Dependent Adaptive Signaling

    Science.gov (United States)

    Zhao, Zhongfu; Koltai, Erika; Ohno, Hideki; Atalay, Mustafa

    2013-01-01

    Abstract The complexity of human DNA has been affected by aerobic metabolism, including endurance exercise and oxygen toxicity. Aerobic endurance exercise could play an important role in the evolution of Homo sapiens, and oxygen was not important just for survival, but it was crucial to redox-mediated adaptation. The metabolic challenge during physical exercise results in an elevated generation of reactive oxygen species (ROS) that are important modulators of muscle contraction, antioxidant protection, and oxidative damage repair, which at moderate levels generate physiological responses. Several factors of mitochondrial biogenesis, such as peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α), mitogen-activated protein kinase, and SIRT1, are modulated by exercise-associated changes in the redox milieu. PGC-1α activation could result in decreased oxidative challenge, either by upregulation of antioxidant enzymes and/or by an increased number of mitochondria that allows lower levels of respiratory activity for the same degree of ATP generation. Endogenous thiol antioxidants glutathione and thioredoxin are modulated with high oxygen consumption and ROS generation during physical exercise, controlling cellular function through redox-sensitive signaling and protein–protein interactions. Endurance exercise-related angiogenesis, up to a significant degree, is regulated by ROS-mediated activation of hypoxia-inducible factor 1α. Moreover, the exercise-associated ROS production could be important to DNA methylation and post-translation modifications of histone residues, which create heritable adaptive conditions based on epigenetic features of chromosomes. Accumulating data indicate that exercise with moderate intensity has systemic and complex health-promoting effects, which undoubtedly involve regulation of redox homeostasis and signaling. Antioxid. Redox Signal. 18, 1208–1246. PMID:22978553

  9. Oxygen Consumption of Elite Distance Runners on an Anti-Gravity Treadmill®

    Directory of Open Access Journals (Sweden)

    David K.P. McNeill, John R. Kline, Hendrick D. de Heer, J. Richard Coast

    2015-06-01

    Full Text Available Lower body positive pressure (LBPP, or ‘anti-gravity’ treadmills® have become increasingly popular among elite distance runners. However, to date, few studies have assessed the effect of body weight support (BWS on the metabolic cost of running among elite runners. This study evaluated how BWS influenced the relationship between velocity and metabolic cost among 6 elite male distance runners. Participants ran three- 16 minute tests consisting of 4 stages of 4 minutes at 8, 7, 6 and 5 min·mile−1 pace (3.35, 3.84, 4.47 and 5.36 m·s−1, while maintaining an aerobic effort (Respiratory Exchange Ratio ≤1.00. One test was run on a regular treadmill, one on an anti-gravity treadmill with 40% BWS and one with 20% BWS being provided. Expired gas data were collected and regression equations used to determine and compare slopes. Significant decreases in oxygen uptake (V̇O2 were found with each increase in BWS (p < 0.001. At 20% BWS, the average decrease in net VO2 was greater than proportional (34%, while at 40% BWS, the average net reduction in VO2 was close to proportional (38%. Across velocities, the slope of the relationship between VO2 and velocity (ΔV̇O2/Δv was steeper with less support. The slopes at both the 20% and 40% BWS conditions were similar, especially when compared to the regular treadmill. Variability in VO2 between athletes was much greater on the LBPP treadmill and was greater with increased levels of BWS. In this study we evaluated the effect of body weight support on V̇O2 among elite distance runners. We have shown that oxygen uptake decreased with support, but not in direct proportion to that support. Further, because of the high variability in oxygen uptake between athletes on the LBPP treadmill, prediction equations may not be reliable and other indicators (heart rate, perceived exertion or directly measured oxygen uptake should be used to guide training intensity when training on the LBPP treadmill.

  10. Oxygen consumption and mortality rate of mice after X radiation under the influence of magnetic fields

    International Nuclear Information System (INIS)

    Rekbi, M.

    1984-01-01

    In this work it was studied whether an influence on the oxygen use was to be expected as a result of a magnetic pulsating field. This could not be determined. An increased effect of the magnetic field with respect to the reduction of the mortality rate was, however, to be observed. Thereby the influence of similar constant and pulsating fields was discussed from various perspectives. The question of the biological effect mechanism of the magnetic field (main issue of the influence of the magnetic field during or after the irradiation) can only be answered by further comprehensive investigations. (orig./MG) [de

  11. Event-Associated Oxygen Consumption Rate Increases ca. Five-Fold When Interictal Activity Transforms into Seizure-Like Events In Vitro

    Directory of Open Access Journals (Sweden)

    Karl Schoknecht

    2017-09-01

    Full Text Available Neuronal injury due to seizures may result from a mismatch of energy demand and adenosine triphosphate (ATP synthesis. However, ATP demand and oxygen consumption rates have not been accurately determined, yet, for different patterns of epileptic activity, such as interictal and ictal events. We studied interictal-like and seizure-like epileptiform activity induced by the GABAA antagonist bicuculline alone, and with co-application of the M-current blocker XE-991, in rat hippocampal slices. Metabolic changes were investigated based on recording partial oxygen pressure, extracellular potassium concentration, and intracellular flavine adenine dinucleotide (FAD redox potential. Recorded data were used to calculate oxygen consumption and relative ATP consumption rates, cellular ATP depletion, and changes in FAD/FADH2 ratio by applying a reactive-diffusion and a two compartment metabolic model. Oxygen-consumption rates were ca. five times higher during seizure activity than interictal activity. Additionally, ATP consumption was higher during seizure activity (~94% above control than interictal activity (~15% above control. Modeling of FAD transients based on partial pressure of oxygen recordings confirmed increased energy demand during both seizure and interictal activity and predicted actual FAD autofluorescence recordings, thereby validating the model. Quantifying metabolic alterations during epileptiform activity has translational relevance as it may help to understand the contribution of energy supply and demand mismatches to seizure-induced injury.

  12. Persistent increase in oxygen consumption and impaired neurovascular coupling after spreading depression in rat neocortex.

    Science.gov (United States)

    Piilgaard, Henning; Lauritzen, Martin

    2009-09-01

    Cortical spreading depression (CSD) is associated with a dramatic failure of brain ion homeostasis and increased energy metabolism. There is strong clinical and experimental evidence to suggest that CSD is the mechanism of migraine, and involved in progressive neuronal injury in stroke and head trauma. Here we tested the hypothesis that single episodes of CSD induced acute hypoxia, and prolonged impairment of neurovascular and neurometabolic coupling. Cortical spreading depression was induced in rat frontal cortex, whereas cortical electrical activity and local field potentials (LFPs) were recorded by glass microelectrodes, cerebral blood flow (CBF) by laser-Doppler flowmetry, and tissue oxygen tension (tpO(2)) with polarographic microelectrodes. Cortical spreading depression increased cerebral metabolic rate of oxygen (CMRO(2)) by 71%+/-6.7% and CBF by 238%+/-48.1% for 1 to 2 mins. For the following 2 h, basal tpO(2) and CBF were reduced whereas basal CMRO(2) was persistently elevated by 8.1%+/-2.9%. In addition, within first hour after CSD we found impaired neurovascular coupling (LFP versus CBF), whereas neurometabolic coupling (LFP versus CMRO(2)) remained unaffected. Impaired neurovascular coupling was explained by both reduced vascular reactivity and suppressed function of cortical inhibitory interneurons. The protracted effects of CSD on basal CMRO(2) and neurovascular coupling may contribute to cellular dysfunction in patients with migraine and acutely injured cerebral cortex.

  13. Regional cerebral blood flow and oxygen consumption during normal human sleep

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Ken [Toho Univ., Tokyo (Japan). School of Medicine

    1989-09-01

    Regional cerebral blood flow (rCBF), regional oxygen extraction fraction (rCEF) and regional cerebral metabolic rate for oxygen (rCMRO{sub 2}) were measured using the continuous inhalation technique for {sup 15}O with positron emission tomography (PET) during both wakefulness and sleep. Ten paid volunteers, with a mean age of 21.6 yrs., were deprived of sleep for a period of approximately 20 hours, and the experiments were performed mostly in the morning. {sup 15}O activity of both whole blood and the plasma, pixel count of PET, total arterial blood oxygen content were used for analysis of rCBF, rOEF and rCMRO{sub 2}. PET scannings were carried out mostly during the very light non-rapid eye movement (NREM) sleep, i.e. stage 1 and/or 2, and wakefulness. About 10 minutes after the start of continuous inhalation of {sup 15}O gas, the {sup 15}O activity of the brain was found to be in a steady-state condition. During this steady-state condition, PET scannings were performed for about 10 minutes. Regions of interest, square in shape and having an area of 2.8 cm{sup 3}, were set in each cortex on PET images of a horizontal cross-section of the brain, set at 45 mm above the orbitomeatal line. The rCBF and rCMRO{sub 2} were analysed in 5 of 10 male subjects during both wakefulness and NREM sleep, and only 3 were done during three sleep stages, including REM sleep. Levels of rCBF and rCMRO{sub 2} were found to be decreased in NREM sleep, and the decreasing rates were calculated at 10.2% and 7.6% from the level of wakefulness, respectively. There was no significant difference in the mean value of rOEF between wakefulness and NREM sleep. There were no significant regional differences found in the rate of decrease among the frontal, temporal and occipital cortices. It was considered that the decrease of rCBF and rCMRO{sub 2} during NREM sleep suggested a decrease of the activity levels in the cerebral functions. (author).

  14. Regional cerebral blood flow and oxygen consumption during normal human sleep

    International Nuclear Information System (INIS)

    Takahashi, Ken

    1989-01-01

    Regional cerebral blood flow (rCBF), regional oxygen extraction fraction (rCEF) and regional cerebral metabolic rate for oxygen (rCMRO 2 ) were measured using the continuous inhalation technique for 15 O with positron emission tomography (PET) during both wakefulness and sleep. Ten paid volunteers, with a mean age of 21.6 yrs., were deprived of sleep for a period of approximately 20 hours, and the experiments were performed mostly in the morning. 15 O activity of both whole blood and the plasma, pixel count of PET, total arterial blood oxygen content were used for analysis of rCBF, rOEF and rCMRO 2 . PET scannings were carried out mostly during the very light non-rapid eye movement (NREM) sleep, i.e. stage 1 and/or 2, and wakefulness. About 10 minutes after the start of continuous inhalation of 15 O gas, the 15 O activity of the brain was found to be in a steady-state condition. During this steady-state condition, PET scannings were performed for about 10 minutes. Regions of interest, square in shape and having an area of 2.8 cm 3 , were set in each cortex on PET images of a horizontal cross-section of the brain, set at 45 mm above the orbitomeatal line. The rCBF and rCMRO 2 were analysed in 5 of 10 male subjects during both wakefulness and NREM sleep, and only 3 were done during three sleep stages, including REM sleep. Levels of rCBF and rCMRO 2 were found to be decreased in NREM sleep, and the decreasing rates were calculated at 10.2% and 7.6% from the level of wakefulness, respectively. There was no significant difference in the mean value of rOEF between wakefulness and NREM sleep. There were no significant regional differences found in the rate of decrease among the frontal, temporal and occipital cortices. It was considered that the decrease of rCBF and rCMRO 2 during NREM sleep suggested a decrease of the activity levels in the cerebral functions. (author)

  15. Temperature dependence of microbial degradation of organic matter in marine sediments: polysaccharide hydrolysis, oxygen consumption, and sulfate reduction

    DEFF Research Database (Denmark)

    Arnosti, C.; Jørgensen, BB; Sagemann, J.

    1998-01-01

    The temperature dependence of representative initial and terminal steps of organic carbon remineralization was measured at 2 temperate sites with annual temperature ranges of 0 to 30 degrees C and 4 to 15 degrees C and 2 Arctic sites with temperatures of 2.6 and -1.7 degrees C. Slurried sediments...... were incubated in a temperature gradient block spanning a temperature range of ca 45 degrees C. The initial step of organic carbon remineralization, macromolecule hydrolysis, was measured via the enzymatic hydrolysis of fluorescently labeled polysaccharides. The terminal steps of organic carbon...... remineralization were monitored through consumption of oxygen and reduction of (SO42-)-S-35. At each of the 4 sites, the temperature response of the initial step of organic carbon remineralization was similar to that of the terminal steps. Although optimum temperatures were always well above ambient environmental...

  16. Measurement of local blood flow and oxygen consumption in evolving irreversible cerebral infarction: an in vivo study in man

    International Nuclear Information System (INIS)

    Baron, J.C.; Rougemont, D.; Lebrun-Grandie, P.; Bousser, M.G.; Cabanis, E.; Bories, J.; Comar, D.; Castaigne, P.

    1982-09-01

    Positron emission tomography (PET) allows in vivo measurement of local cerebral blood flow (1CBF), oxygen consumption rate (1CMRO 2 ) and glucose utilisation (1CMRG1c) in man. Although 1CMRG1c is accessible in animals, this is not the case for 1CMRO 2 , an excellent index of local functional state. PET imaging of the local interrelationship of CBF and metabolism in completed ischemic stroke has attracted considerable interest because of its potential to differentiate irreversibly damaged from viable tissue on the basis of the CBF- metabolism patterns. Several qualitative or semi-quantitative pioneering studies provided a limited insight into this question, while the single truly quantitative study was only briefly reported. We report here a detailed study of the local CBF-CMRO 2 quantitative patterns in irreversibly infarcted brain regions

  17. Methane emission and oxygen consumption in the hydroelectric dam of Petit Saut in French Guyana

    International Nuclear Information System (INIS)

    Galy-Lacaux, C.; Jambert, C.; Delmas, R.; Dumestre, J.F.; Labroue, L.; Cerdan, P.; Richard, S.

    1996-01-01

    Methane emissions from the hydroelectric dam of Petit-Saut, in French Guyana, were measured over a 20-months period. Since the beginning of the reservoir filling (January 1994), 300 km 2 of tropical forest have been submerged. Biological CH 4 oxidation, in the surface water of the lake and in the river downstream of the dam, lead to an intense 0 2 consumption. Emissions of CH 4 by diffusion into the atmosphere or by degassing of the water released into the river as well as the stock of dissolved gas in the lake, and their temporal dynamics, were studied. Maximum emissions of 700 t (CH 4 ) per day were attained in February 1994, corresponding to maximum dissolved CH 4 concentrations of 14 mg l -1 in the water column. Total emissions since January 1994, were calculated from the whole data set. (authors). 7 refs., 2 figs., 1 tab

  18. Regional myocardial oxygen consumption determined noninvasively in humans with [1-11C]acetate and dynamic positron tomography

    International Nuclear Information System (INIS)

    Armbrecht, J.J.; Buxton, D.B.; Brunken, R.C.; Phelps, M.E.; Schelbert, H.R.

    1989-01-01

    Experimental studies of animals have previously demonstrated the validity of [1-11C]acetate as a tracer of oxidative metabolism for use with positron emission tomography. The present study was undertaken to define in normal human volunteers the relation between myocardial clearance kinetics of [1-11C]acetate, and the rate-pressure product as an index of myocardial oxygen consumption. Twenty-two studies were performed of 12 volunteers. The rate-pressure product was increased with continuous supine bicycle exercise in six studies. Of the 16 resting studies, seven were performed in the fasted state and nine following an oral glucose load, to define possible effects of substrate availability on the tracer-tissue kinetics. Myocardial tissue time-activity curves were biexponential. Clearance of activity was homogeneous throughout the myocardium. The rate constants k1, obtained from biexponential fitting, and kmono, obtained by monoexponential fitting of the initial linear portion of the time-activity curves, correlated well with the rate-pressure product. Although the correlation coefficient was higher for k1 than for kmono (0.95 vs. 0.91), analysis on a sectorial basis showed less regional variability in kmono. This suggests that kmono, which is more practical than k1 because it requires shorter acquisition times, may be more clinically and experimentally useful for detection of myocardial segments with abnormal oxygen consumption. Overall, changes in myocardial substrate supply were without significant effect on the relation between the rate constants (k1 and kmono) and the rate-pressure product, although a small decrease in kmono/rate-pressure product was observed following oral glucose by paired analysis in four subjects

  19. Children with Burn Injury Have Impaired Cardiac Output during Submaximal Exercise.

    Science.gov (United States)

    Rivas, Eric; Herndon, David N; Beck, Kenneth C; Suman, Oscar E

    2017-10-01

    Burn trauma damages resting cardiac function; however, it is currently unknown if the cardiovascular response to exercise is likewise impaired. We tested the hypothesis that, in children, burn injury lowers cardiac output (Q˙) and stroke volume (SV) during submaximal exercise. Five children with 49% ± 4% total body surface area (BSA) burned (two female, 11.7 ± 1 yr, 40.4 ± 18 kg, 141.1 ± 9 cm) and eight similar nonburned controls (five female, 12.5 ± 2 yr, 58.0 ± 17 kg, 147.3 ± 12 cm) with comparable exercise capacity (peak oxygen consumption [peak V˙O2]: 31.9 ± 11 vs 36.8 ± 8 mL O2·kg·min, P = 0.39) participated. The exercise protocol entailed a preexercise (pre-EX) rest period followed by 3-min exercise stages at 20 W and 50 W. V˙O2, HR, Q˙ (via nonrebreathing), SV (Q˙/HR), and arteriovenous O2 difference ([a-v]O2diff, Q˙/ V˙O2) were the primary outcome variables. Using a 2-way factorial ANOVA (group [G] × exercise [EX]), we found that Q˙ was approximately 27% lower in the burned than the nonburned group at 20 W of exercise (burned 5.7 ± 1.0 vs nonburned: 7.9 ± 1.8 L·min) and 50 W of exercise (burned 6.9 ± 1.6 vs nonburned 9.2 ± 3.2 L·min) (G-EX interaction, P = 0.012). SV did not change from rest to exercise in burned children but increased by approximately 24% in the nonburned group (main effect for EX, P = 0.046). Neither [a-v] O2diff nor V˙O2 differed between groups at rest or exercise, but HR response to exercise was reduced in the burn group (G-EX interaction, P = 0.004). When normalized to BSA, SV (index) was similar between groups; however, Q˙ (index) remained attenuated in the burned group (G-EX interaction, P exercise. Further investigation of hemodynamic function during exercise will provide insights important for cardiovascular rehabilitation in burned children.

  20. F-door spaces and F-submaximal spaces

    Directory of Open Access Journals (Sweden)

    Lobna Dridi

    2013-04-01

    Full Text Available Submaximal spaces and door spaces play an enigmatic role in topology. In this paper, reinforcing this role, we are concerned with reaching two main goals: The first one is to characterize topological spaces X such that F(X is a submaximal space (resp., door space for some covariant functor Ff rom the category Top to itself. T0, and FH functors are completely studied. Secondly, our interest is directed towards the characterization of maps f given by a flow (X, f in the category Set, such that (X,P(f is submaximal (resp., door where P(f is a topology on X whose closed sets are exactly the f-invariant sets.

  1. The relationship between heart rate and rate of oxygen consumption in Galapagos marine iguanas (Amblyrhynchus cristatus) at two different temperatures.

    Science.gov (United States)

    Butler, Patrick J; Frappell, Peter B; Wang, Tobias; Wikelski, Martin

    2002-07-01

    To enable the use of heart rate (fH) for estimating field metabolic rate (FMR) in free-ranging Galapagos marine iguanas Amblyrhynchus cristatus, we determined the relationships between fH and mass-specific rate of oxygen consumption (sVO2) in seven iguanas before and during exercise on a treadmill and during the post-exercise period. The experiments were conducted at 27 and 35 degrees C, which are the temperatures that represent the lowest and highest average body temperatures of these animals in the field during summer. There were linear and significant relationships between fH and sVO2 at both temperatures (r(2)=0.86 and 0.91 at 27 degrees C and 36 degrees C, respectively). The slopes of the two regression lines did not differ, but there were significant differences in their intercepts. Thus, while heart rate can be used to predict FMR, the effects of temperature on the intercept of the regression must be taken into account when converting fH to sVO2. On the basis of our data, this can be achieved by applying the following formula: sVO2=0.0113fH-0.2983Q(10)((T(b)-27)/10). The increase in sVO2 with elevated body temperature results from an increase in fH, with no significant change in mass-specific oxygen pulse (sO(2) pulse; cardiac stroke volume times the difference in oxygen content between arterial and mixed venous blood). However, during exercise at both temperatures, increases in fH are insufficient to provide all of the additional O(2) required and there are also significant increases in the sO(2) pulses. This creates the situation whereby the same fH at the two temperatures can represent different values of sVO2.

  2. Hepatic blood flow and splanchnic oxygen consumption in patients with liver failure. Effect of high-volume plasmapheresis.

    Science.gov (United States)

    Clemmesen, J O; Gerbes, A L; Gülberg, V; Hansen, B A; Larsen, F S; Skak, C; Tygstrup, N; Ott, P

    1999-02-01

    Liver failure represents a major therapeutic challenge, and yet basic pathophysiological questions about hepatic perfusion and oxygenation in this condition have been poorly investigated. In this study, hepatic blood flow (HBF) and splanchnic oxygen delivery (DO2, sp) and oxygen consumption (VO2,sp) were assessed in patients with liver failure defined as hepatic encephalopathy grade II or more. Measurements were repeated after high-volume plasmapheresis (HVP) with exchange of 8 to 10 L of plasma. HBF was estimated by use of constant infusion of D-sorbitol and calculated according to Fick's principle from peripheral artery and hepatic vein concentrations. In 14 patients with acute liver failure (ALF), HBF (1.78 +/- 0.78 L/min) and VO2,sp (3.9 +/- 0.9 mmol/min) were higher than in 11 patients without liver disease (1.07 +/- 0.19 L/min, P HVP, HBF increased from 1.67 +/- 0.72 to 2.07 +/- 1.11 L/min (n=11) in ALF, and from 1.89 +/- 1.32 to 2.34 +/- 1.54 L/min (n=7) in AOCLD, P HVP. Blood flow was redirected to the liver as the systemic vascular resistance index increased (1,587 +/- 650 vs. 2, 020 +/- 806 Dyne. s. cm-5. m2, P HVP, but as cardiac output increased from 9.1 +/- 2.8 to 10.1 +/- 2.9 L/min (P HVP (n=18), DO2,sp increased by 15% (P HVP. Changes of ET-1 were positively correlated with changes in HBF (P HVP (P HVP did not correlate. Our data suggest that liver failure is associated with increased HBF and VO2, sp. HVP further increased HBF and DO2,sp but VO2,sp was unchanged, indicating that splanchnic hypoxia was not present.

  3. Modeling of oxygen gas diffusion and consumption during the oxic transient in a disposal cell of radioactive waste

    International Nuclear Information System (INIS)

    De Windt, Laurent; Marsal, François; Corvisier, Jérôme; Pellegrini, Delphine

    2014-01-01

    Highlights: • This paper deals with the geochemistry of underground HLW disposals. • The oxic transient is a key issue in performance assessment (e.g. corrosion, redox). • A reactive transport model is explicitly coupled to gas diffusion and reactivity. • Application to in situ experiment (Tournemire laboratory) and HLW disposal cell. • Extent of the oxidizing/reducing front is investigated by sensitivity analysis. - Abstract: The oxic transient in geological radioactive waste disposals is a key issue for the performance of metallic components that may undergo high corrosion rates under such conditions. A previous study carried out in situ in the argillite formation of Tournemire (France) has suggested that oxic conditions could have lasted several years. In this study, a multiphase reactive transport model is performed with the code HYTEC to analyze the balance between the kinetics of pyrite oxidative dissolution, the kinetics of carbon steel corrosion and oxygen gas diffusion when carbon steel components are emplaced in the geological medium. Two cases were modeled: firstly, the observations made in situ have been reproduced, and the model established was then applied to a disposal cell for high-level waste (HLW) in an argillaceous formation, taking into account carbon steel components and excavated damaged zones (EDZ). In a closed system, modeling leads to a complete and fast consumption of oxygen in both cases. Modeling results are more consistent with the in situ test while considering residual voids between materials and/or a water unsaturated state allowing for oxygen gas diffusion (open conditions). Under similar open conditions and considering ventilation of the handling drifts, a redox contrast occurs between reducing conditions at the back of the disposal cell (with anoxic corrosion of steel and H 2 production) and oxidizing conditions at the front of the cell (with oxic corrosion of steel). The extent of the oxidizing/reducing front in the

  4. Critical oxygen tension and the effect of hypoxia on the oxygen consumption of the striped catfish, Pangasius hypophthaimos (Pangasiidae)

    DEFF Research Database (Denmark)

    Lefevre, S.; Bayley, Mark; Wang, Tobias

    2008-01-01

    The striped catfish (Pangasius hypophthalmus) is an air-breathing teleost that uses a modified swim bladder for aerial gas exchange. Pangasius is of enormous importance for aquaculture industry in the Mekong Delta(Vietnam), but little is known about its physiology. We have initiated a series...... consumption (VO2), measured with intermittent closed respirometry, was 67.8 ± 5.1 mLO2/kg/h when the fish were maintained without access to air at 27 °C. The critical oxygen tension (Pcrit) at these conditions was 57.9 ± 8.9 mmHg (N = 7). The metabolic response to aquatic hypoxia was studied in fish subjected....... The ontogenetic effect of environmental PO2 on metabolism is currently under investigation with fish being reared in 30%, 60% and 100% saturation. Data on resting VO2and Pcrit will be presented and discussed for these animals....

  5. Low Oxygen Consumption is Related to a Hypomethylation and an Increased Secretion of IL-6 in Obese Subjects with Sleep Apnea-Hypopnea Syndrome.

    Science.gov (United States)

    Lopez-Pascual, Amaya; Lasa, Arrate; Portillo, María P; Arós, Fernando; Mansego, María L; González-Muniesa, Pedro; Martinez, J Alfredo

    2017-01-01

    Deoxyribonucleic acid (DNA) methylation is an epigenetic modification involved in gene expression regulation, usually via gene silencing, which contributes to the risks of many multifactorial diseases. The aim of the present study was to analyze the influence of resting oxygen consumption on global and gene DNA methylation as well as protein secretion of inflammatory markers in blood cells from obese subjects with sleep apnea-hypopnea syndrome (SAHS). A total of 44 obese participants with SAHS were categorized in 2 groups according to their resting oxygen consumption. DNA methylation levels were evaluated using a methylation-sensitive high resolution melting approach. The analyzed interleukin 6 (IL6) gene cytosine phosphate guanine (CpG) islands showed a hypomethylation, while serum IL-6 was higher in the low compared to the high oxygen consumption group (p DNA methylation of tumor necrosis factor (B = -0.82, 95% CI -1.33 to -0.30) and long interspersed nucleotide element 1 (B = -0.46; 95% CI -0.87 to -0.04) gene CpGs were found. Finally, studied CpG methylation levels of serpin peptidase inhibitor, clade E member 1 (r = 0.43; p = 0.01), and IL6 (r = 0.41; p = 0.02) were positively associated with fat-free mass. These findings suggest a potential role of oxygen in the regulation of inflammatory genes. Oxygen consumption measurement at rest could be proposed as a clinical biomarker of metabolic health. © 2017 S. Karger AG, Basel.

  6. Coalbed gas desorption in canisters: Consumption of trapped atmospheric oxygen and implications for measured gas quality

    International Nuclear Information System (INIS)

    Jin, Hui; Schimmelmann, Arndt; Mastalerz, Maria; Pope, James; Moore, Tim A.

    2010-01-01

    Desorption canisters are routinely employed to quantify coalbed gas contents in coals. If purging with inert gas or water flooding is not used, entrapment of air with ∝ 78.08 vol.% nitrogen (N 2 ) in canisters during the loading of coal results in contamination by air and subsequent overestimates of N 2 in desorbed coalbed gas. Pure coalbed gas does not contain any elemental oxygen (O 2 ), whereas air contamination originally includes ∝ 20.95 vol.% O 2 and has a N 2 /O 2 volume ratio of ∝ 3.73. A correction for atmospheric N 2 is often attempted by quantifying O 2 in headspace gas and then proportionally subtracting atmospheric N 2 . However, this study shows that O 2 is not a conservative proxy for air contamination in desorption canisters. Time-series of gas chromatographic (GC) compositional data from several desorption experiments using high volatile bituminous coals from the Illinois Basin and a New Zealand subbituminous coal document that atmospheric O 2 was rapidly consumed, especially during the first 24 h. After about 2 weeks of desorption, the concentration of O 2 declined to near or below GC detection limits. Irreversible loss of O 2 in desorption canisters is caused by biological, chemical, and physical mechanisms. The use of O 2 as a proxy for air contamination is justified only immediately after loading of desorption canisters, but such rapid measurements preclude meaningful assessment of coalbed gas concentrations. With increasing time and progressive loss of O 2 , the use of O 2 content as a proxy for atmospheric N 2 results in overestimates of N 2 in desorbed coalbed gas. The indicated errors for nitrogen often range in hundreds of %. Such large analytical errors have a profound influence on market choices for CBM gas. An erroneously calculated N 2 content in CBM would not meet specifications for most pipeline-quality gas. (author)

  7. Regulation of ventilation and oxygen consumption by delta- and mu-opioid receptor agonists.

    Science.gov (United States)

    Schaeffer, J I; Haddad, G G

    1985-09-01

    To study the effect of endorphins on metabolic rate and on the relationship between O2 consumption (VO2) and ventilation, we administered enkephalin analogues (relatively selective delta-receptor agonists) and a morphiceptin analogue (a highly selective mu-receptor agonist) intracisternally in nine unanesthetized chronically instrumented adult dogs. Both delta- and mu-agonists decreased VO2 by 40-60%. delta-Agonists induced a dose-dependent decrease in mean instantaneous minute ventilation (VT/TT) associated with periodic breathing. The decrease in VT/TT started and resolved prior to the decrease and returned to baseline of VO2, respectively. In contrast, the mu-agonists induced an increase in VT/TT associated with rapid shallow breathing. Arterial PCO2 increased and arterial PO2 decreased after both delta- and mu-agonists. Low doses of intracisternal naloxone (0.002-2.0 micrograms/kg) reversed the opioid effect on VT/TT but not on VO2; higher doses of naloxone (5-25 micrograms/kg) reversed both. Naloxone administered alone had no effect on VT/TT or VO2. These data suggest that 1) both delta- and mu-agonists induce alveolar hypoventilation despite a decrease in VO2, 2) this hypoventilation results from a decrease in VT/TT after delta-agonists but an increase in dead space ventilation after mu-agonists, and 3) endorphins do not modulate ventilation and metabolic rate tonically, but we speculate that they may do so in response to stressful stimulation.

  8. Coalbed gas desorption in canisters: Consumption of trapped atmospheric oxygen and implications for measured gas quality

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Hui; Schimmelmann, Arndt [Indiana University, Dept. of Geological Sciences, Bloomington, IN 47405-1405 (United States); Mastalerz, Maria [Indiana University, Indiana Geological Survey, Bloomington, IN 47405-2208 (United States); Pope, James [CRL Energy Ltd., 123 Blenheim Road, Christchurch (New Zealand); University of Canterbury, Dept. of Geological Sciences, Christchurch (New Zealand); Moore, Tim A. [University of Canterbury, Dept. of Geological Sciences, Christchurch (New Zealand); P.T. Arrow Energy Indonesia, Wisma Anugraha, Jl. Taman Kemang No. 32B, Jakarta Selatan (Indonesia)

    2010-01-07

    Desorption canisters are routinely employed to quantify coalbed gas contents in coals. If purging with inert gas or water flooding is not used, entrapment of air with {proportional_to} 78.08 vol.% nitrogen (N{sub 2}) in canisters during the loading of coal results in contamination by air and subsequent overestimates of N{sub 2} in desorbed coalbed gas. Pure coalbed gas does not contain any elemental oxygen (O{sub 2}), whereas air contamination originally includes {proportional_to} 20.95 vol.% O{sub 2} and has a N{sub 2}/O{sub 2} volume ratio of {proportional_to} 3.73. A correction for atmospheric N{sub 2} is often attempted by quantifying O{sub 2} in headspace gas and then proportionally subtracting atmospheric N{sub 2}. However, this study shows that O{sub 2} is not a conservative proxy for air contamination in desorption canisters. Time-series of gas chromatographic (GC) compositional data from several desorption experiments using high volatile bituminous coals from the Illinois Basin and a New Zealand subbituminous coal document that atmospheric O{sub 2} was rapidly consumed, especially during the first 24 h. After about 2 weeks of desorption, the concentration of O{sub 2} declined to near or below GC detection limits. Irreversible loss of O{sub 2} in desorption canisters is caused by biological, chemical, and physical mechanisms. The use of O{sub 2} as a proxy for air contamination is justified only immediately after loading of desorption canisters, but such rapid measurements preclude meaningful assessment of coalbed gas concentrations. With increasing time and progressive loss of O{sub 2}, the use of O{sub 2} content as a proxy for atmospheric N{sub 2} results in overestimates of N{sub 2} in desorbed coalbed gas. The indicated errors for nitrogen often range in hundreds of %. Such large analytical errors have a profound influence on market choices for CBM gas. An erroneously calculated N{sub 2} content in CBM would not meet specifications for most pipeline

  9. Influence of menstrual phase on ventilatory response to submaximal ...

    African Journals Online (AJOL)

    Objectives. To determine whether an increase in respiratory drive, due to elevated progesterone and oestrogen concentration during various menstrual phases, persists throughout prolonged submaximal exercise and potentially contributes to fatigue. Furthermore, to determine whether the difference in the ventilatory ...

  10. Submaximal exercise capacity and maximal power output in polio subjects

    NARCIS (Netherlands)

    Nollet, F.; Beelen, A.; Sargeant, A. J.; de Visser, M.; Lankhorst, G. J.; de Jong, B. A.

    2001-01-01

    OBJECTIVES: To compare the submaximal exercise capacity of polio subjects with postpoliomyelitis syndrome (PPS) and without (non-PPS) with that of healthy control subjects, to investigate the relationship of this capacity with maximal short-term power and quadriceps strength, and to evaluate

  11. Noninvasive determination of myocardial blood flow, oxygen consumption and efficiency in normal humans by carbon-11 acetate positron emission tomography imaging

    International Nuclear Information System (INIS)

    Porenta, G.; Cherry, S.; Czernin, J.; Brunken, R.; Kuhle, W.; Hashimoto, T.; Schelbert, H.R.

    1999-01-01

    The aims of this study were: (1) to measure noninvasively and near simultaneously myocardial blood flow, oxygen consumption, and contractile function and (2) to analyze myocardial energy expenditure and efficiency at rest and during dobutamine stress in normal humans. Dynamic and gated carbon-11 acetate positron emission tomography (PET) imaging was performed in 11 normal subjects. The initial uptake of 11 C-acetate was measured to estimate myocardial blood flow. Oxygen consumption was derived from the monoexponential slope of the 11 C-clearance curve recorded during myocardial washout. ECG-gated systolic and diastolic images were acquired during the peak myocardial 11 C activity to measure left ventricular radius, myocardial wall thickness, and long axis length. Myocardial oxygen consumption and parameters of cardiac geometry were used to determine myocardial energetics and cardiac efficiency by tension-area area analysis. Myocardial blood flow averaged 0.8±0.06 ml min -1 g -1 at rest and 1.48±0.15 ml min -1 g -1 during dobutamine stress. Oxygen delivery and consumption were 151±13 and 88±15 μl O 2 min -1 g -1 at rest and increased to 291±31 and 216±31 μl O 2 min -1 g -1 , respectively, during pharmacological stress (P 11 C acetate imaging provides the unique capability to study noninvasively determinants of myocardial energy delivery, expenditure, and efficiency. (orig.)

  12. Bilateral changes in forearm oxygen consumption at rest and after exercise in patients with unilateral Repetitive Strain Injury : A case control study

    NARCIS (Netherlands)

    J. Oosterhof; D. Thijssen; M. Hopman; J. Brunnekreef

    2011-01-01

    To investigate whether oxygen consumption and blood flow at rest and after exercise are lower in the affected arm of patients with repetitive strain injury (RSI) compared to controls, and lower in the healthy nonaffected forearm within patients with unilateral RSI. RSI is considered an upper

  13. Pyruvate induces transient tumor hypoxia by enhancing mitochondrial oxygen consumption and potentiates the anti-tumor effect of a hypoxia-activated prodrug TH-302.

    Directory of Open Access Journals (Sweden)

    Yoichi Takakusagi

    Full Text Available BACKGROUND: TH-302 is a hypoxia-activated prodrug (HAP of bromo isophosphoramide mustard that is selectively activated within hypoxic regions in solid tumors. Our recent study showed that intravenously administered bolus pyruvate can transiently induce hypoxia in tumors. We investigated the mechanism underlying the induction of transient hypoxia and the combination use of pyruvate to potentiate the anti-tumor effect of TH-302. METHODOLOGY/RESULTS: The hypoxia-dependent cytotoxicity of TH-302 was evaluated by a viability assay in murine SCCVII and human HT29 cells. Modulation in cellular oxygen consumption and in vivo tumor oxygenation by the pyruvate treatment was monitored by extracellular flux analysis and electron paramagnetic resonance (EPR oxygen imaging, respectively. The enhancement of the anti-tumor effect of TH-302 by pyruvate treatment was evaluated by monitoring the growth suppression of the tumor xenografts inoculated subcutaneously in mice. TH-302 preferentially inhibited the growth of both SCCVII and HT29 cells under hypoxic conditions (0.1% O2, with minimal effect under aerobic conditions (21% O2. Basal oxygen consumption rates increased after the pyruvate treatment in SCCVII cells in a concentration-dependent manner, suggesting that pyruvate enhances the mitochondrial respiration to consume excess cellular oxygen. In vivo EPR oxygen imaging showed that the intravenous administration of pyruvate globally induced the transient hypoxia 30 min after the injection in SCCVII and HT29 tumors at the size of 500-1500 mm(3. Pretreatment of SCCVII tumor bearing mice with pyruvate 30 min prior to TH-302 administration, initiated with small tumors (∼ 550 mm(3, significantly delayed tumor growth. CONCLUSIONS/SIGNIFICANCE: Our in vitro and in vivo studies showed that pyruvate induces transient hypoxia by enhancing mitochondrial oxygen consumption in tumor cells. TH-302 therapy can be potentiated by pyruvate pretreatment if started at the

  14. Pyruvate induces transient tumor hypoxia by enhancing mitochondrial oxygen consumption and potentiates the anti-tumor effect of a hypoxia-activated prodrug TH-302.

    Science.gov (United States)

    Takakusagi, Yoichi; Matsumoto, Shingo; Saito, Keita; Matsuo, Masayuki; Kishimoto, Shun; Wojtkowiak, Jonathan W; DeGraff, William; Kesarwala, Aparna H; Choudhuri, Rajani; Devasahayam, Nallathamby; Subramanian, Sankaran; Munasinghe, Jeeva P; Gillies, Robert J; Mitchell, James B; Hart, Charles P; Krishna, Murali C

    2014-01-01

    TH-302 is a hypoxia-activated prodrug (HAP) of bromo isophosphoramide mustard that is selectively activated within hypoxic regions in solid tumors. Our recent study showed that intravenously administered bolus pyruvate can transiently induce hypoxia in tumors. We investigated the mechanism underlying the induction of transient hypoxia and the combination use of pyruvate to potentiate the anti-tumor effect of TH-302. The hypoxia-dependent cytotoxicity of TH-302 was evaluated by a viability assay in murine SCCVII and human HT29 cells. Modulation in cellular oxygen consumption and in vivo tumor oxygenation by the pyruvate treatment was monitored by extracellular flux analysis and electron paramagnetic resonance (EPR) oxygen imaging, respectively. The enhancement of the anti-tumor effect of TH-302 by pyruvate treatment was evaluated by monitoring the growth suppression of the tumor xenografts inoculated subcutaneously in mice. TH-302 preferentially inhibited the growth of both SCCVII and HT29 cells under hypoxic conditions (0.1% O2), with minimal effect under aerobic conditions (21% O2). Basal oxygen consumption rates increased after the pyruvate treatment in SCCVII cells in a concentration-dependent manner, suggesting that pyruvate enhances the mitochondrial respiration to consume excess cellular oxygen. In vivo EPR oxygen imaging showed that the intravenous administration of pyruvate globally induced the transient hypoxia 30 min after the injection in SCCVII and HT29 tumors at the size of 500-1500 mm(3). Pretreatment of SCCVII tumor bearing mice with pyruvate 30 min prior to TH-302 administration, initiated with small tumors (∼ 550 mm(3)), significantly delayed tumor growth. Our in vitro and in vivo studies showed that pyruvate induces transient hypoxia by enhancing mitochondrial oxygen consumption in tumor cells. TH-302 therapy can be potentiated by pyruvate pretreatment if started at the appropriate tumor size and oxygen concentration.

  15. Oxygen and SO2 Consumption Rates in White and Rosé Wines: Relationship with and Effects on Wine Chemical Composition.

    Science.gov (United States)

    Carrascón, Vanesa; Bueno, Mónica; Fernandez-Zurbano, Purificación; Ferreira, Vicente

    2017-11-01

    This Article addresses the study of O 2 and SO 2 consumption rates of white and rosé wines, their relationship to the initial chemical composition, and their effects on the chemical changes experienced by wine during oxidation. Eight wines were subjected to five consecutive air-saturation cycles. O 2 was monitored periodically; SO 2 , color, and antioxidant indexes were determined after each cycle, and the initial and final compositions of the wines were thoroughly determined. Wines consumed oxygen at progressively decreasing rates. In the last cycles, after a strong decrease, consistent increases of oxygen levels were seen. Oxygen consumption rates were satisfactorily modeled, being proportional to wine copper, quercetin, and kaempherol contents and negatively proportional to cinnamic acids. SO 2 consumption rates were highly diverse between wines and were positively related to free SO 2 , Mn, and pH, among others. In the last saturations, SO 2 consumption took place regardless of O 2 consumption, implying that SO 2 should reduce chemical species oxidized in previous saturations. Some volatile phenols seem to be the end point of radical-mediated oxidation of polyphenols taking place preferably in the first saturation.

  16. Wii, Kinect, and Move. Heart Rate, Oxygen Consumption, Energy Expenditure, and Ventilation due to Different Physically Active Video Game Systems in College Students.

    Science.gov (United States)

    Scheer, Krista S; Siebrant, Sarah M; Brown, Gregory A; Shaw, Brandon S; Shaw, Ina

    Nintendo Wii, Sony Playstation Move , and Microsoft XBOX Kinect are home video gaming systems that involve player movement to control on-screen game play. Numerous investigations have demonstrated that playing Wii is moderate physical activity at best, but Move and Kinect have not been as thoroughly investigated. The purpose of this study was to compare heart rate, oxygen consumption, and ventilation while playing the games Wii Boxing, Kinect Boxing, and Move Gladiatorial Combat. Heart rate, oxygen consumption, and ventilation were measured at rest and during a graded exercise test in 10 males and 9 females (19.8 ± 0.33 y, 175.4 ± 2.0 cm, 80.2 ± 7.7 kg,). On another day, in a randomized order, the participants played Wii Boxing, K inect Boxing, and Move Gladiatorial Combat while heart rate, ventilation, and oxygen consumption were measured. There were no differences in heart rate (116.0 ± 18.3 vs. 119.3 ± 17.6 vs. 120.1 ± 17.6 beats/min), oxygen consumption (9.2 ± 3.0 vs. 10.6 ± 2.4 vs. 9.6 ± 2.4 ml/kg/min), or minute ventilation (18.9 ± 5.7 vs. 20.8 ± 8.0 vs. 19.7 ± 6.4 L/min) when playing Wii boxing, Kinect boxing, or Move Gladiatorial Combat (respectively). Playing Nintendo Wii Boxing, XBOX Kinect Boxing, and Sony PlayStation Move Gladiatorial Combat all increase heart rate, oxygen consumption, and ventilation above resting levels but there were no significant differences between gaming systems. Overall, playing a "physically active" home video game system does not meet the minimal threshold for moderate intensity physical activity, regardless of gaming system.

  17. Effects of metal contamination in situ on osmoregulation and oxygen consumption in the mudflat fiddler crab Uca rapax (Ocypodidae, Brachyura).

    Science.gov (United States)

    Capparelli, Mariana V; Abessa, Denis M; McNamara, John C

    2016-01-01

    The contamination of estuaries by metals can impose additional stresses on estuarine species, which may exhibit a limited capability to adjust their regulatory processes and maintain physiological homeostasis. The mudflat fiddler crab Uca rapax is a typical estuarine crab, abundant in both pristine and contaminated areas along the Atlantic coast of Brazil. This study evaluates osmotic and ionic regulatory ability and gill Na(+)/K(+)-ATPase activity in different salinities (Rio Itapanhaú, Bertioga>Picinguaba, Ubatuba [pristine reference site]). Our findings show that the contamination of U. rapax by metals in situ leads to bioaccumulation and induces biochemical and physiological changes compared to crabs from the pristine locality. U. rapax from the contaminated sites exhibit stronger hyper- and hypo-osmotic regulatory abilities and show greater gill Na(+)/K(+)-ATPase activities than crabs from the pristine site, revealing that the underlying biochemical machinery can maintain systemic physiological processes functioning well. However, oxygen consumption, particularly at elevated temperatures, decreases in crabs showing high bioaccumulation titers but increases in crabs with low/moderate bioaccumulation levels. These data show that U. rapax chronically contaminated in situ exhibits compensatory biochemical and physiological adjustments, and reveal the importance of studies on organisms exposed to metals in situ, particularly estuarine invertebrates subject to frequent changes in natural environmental parameters like salinity and temperature. Copyright © 2016. Published by Elsevier Inc.

  18. [Oxygen peak consumption is a better predictor of cardiovascular risk than handgrip strength in older Chilean women].

    Science.gov (United States)

    Farías-Valenzuela, Claudio; Pérez-Luco, Cristian; Ramírez-Campillo, Rodrigo; Álvarez, Cristian; Castro-Sepúlveda, Mauricio

    Handgrip strength (HS) and peak oxygen consumption (Vo2peak) are powerful predictors of cardiovascular risk, although it is unknown which of the two variables is the better predictor. The objective of the following study was to relate HS and Vo2peak to cardiovascular risk markers in older Chilean women. Physically active adult women (n=51; age, 69±4.7years) participated in this study. The HS and Vo2peak were evaluated and related to the anthropometric variables of body mass, body mass index (BMI), waist circumference (WC), hip circumference (HC), waist ratio (WR), and waist height ratio (WHR), as well as with the cardiovascular variables systolic (SBP) and diastolic (DBP) and cardiac recovery in one minute (RHR1). A multilinear regression model was used for the analysis of the associated variables (Pcardiovascular risk markers associated (Pcardiovascular risk markers, Vo2peak offers greater associative power with these cardiovascular risk factors. Copyright © 2017 SEGG. Publicado por Elsevier España, S.L.U. All rights reserved.

  19. Concurrent validity of the PAM accelerometer relative to the MTI Actigraph using oxygen consumption as a reference.

    Science.gov (United States)

    Slootmaker, S M; Chin A Paw, M J M; Schuit, A J; van Mechelen, W; Koppes, L L J

    2009-02-01

    The purpose of this study was to examine the concurrent validity of the Personal Activity Monitor (PAM) accelerometer relative to the Actigraph accelerometer using oxygen consumption as a reference, and to assess the test-retest reliability of the PAM. Thirty-two fit, normal weight adults (aged 21-54) performed two activities, treadmill walking and stair walking, while wearing the PAM, the Actigraph and the Cosmed K4b(2). Correlation coefficients and agreement in absolute energy expenditure (EE) levels between PAM, Actigraph and Cosmed were calculated. The test-retest reliability was examined among 296 PAM's using a laboratory shaker. Intraclass correlation coefficients (ICC) and coefficient of variation (CV) were determined. Correlations for treadmill walking and stair walking, respectively, were r(2)=0.95 and r(2)=0.65 for PAM with Actigraph, r(2)=0.82 and r(2)=0.93 for PAM with VO(2) and r(2)=0.64 and 0.74 for Actigraph with VO(2). Both the PAM and Actigraph underestimated EE during treadmill and stair walking by a substantial amount. The test-retest reliability of the PAM was high [ICC=0.80; 95% confidence interval (CI) (0.28;0.92) and intra-CV=1.5%]. The PAM and Actigraph accelerometer are comparable in assessing bodily movement during treadmill and stair walking. The PAM is a valid device to rank subjects in EE and can be useful in collecting objective data to monitor habitual physical activity.

  20. Excess postexercise oxygen consumption is unaffected by the resistance and aerobic exercise order in an exercise session.

    Science.gov (United States)

    Oliveira, Norton L; Oliveira, Jose

    2011-10-01

    The main purpose of this study was to compare the magnitude and duration of excess postexercise oxygen consumption (EPOC) after 2 exercise sessions with different exercise mode orders, resistance followed by aerobic exercise (R-A); aerobic by resistance exercise (A-R). Seven young men (19.6 ± 1.4 years) randomly underwent the 2 sessions. Aerobic exercise was performed on a treadmill for 30 minutes (80-85% of reserve heart rate). Resistance exercise consisted of 3 sets of 10 repetition maximum on 5 exercises. Previous to the exercise sessions, V(O2), heart rate, V(CO2), and respiratory exchange rate (RER) were measured for 15 minutes and again during recovery from exercise for 60 minutes. The EPOC magnitude was not significantly different between R-A (5.17 ± 2.26 L) and A-R (5.23 ± 2.48 L). Throughout the recovery period (60 minutes), V(O2) and HR values were significantly higher than those observed in the pre-exercise period (p better to start a training session.

  1. A procedure for the measurement of Oxygen Consumption Rates (OCRs) in red wines and some observations about the influence of wine initial chemical composition.

    Science.gov (United States)

    Marrufo-Curtido, Almudena; Carrascón, Vanesa; Bueno, Mónica; Ferreira, Vicente; Escudero, Ana

    2018-05-15

    The rates at which wine consumes oxygen are important technological parameters for whose measurement there are not accepted procedures. In this work, volumes of 8 wines are contacted with controlled volumes of air in air-tight tubes containing oxygen-sensors and are further agitated at 25 °C until O 2 consumption is complete. Three exposure levels of O 2 were used: low (10 mg/L) and medium or high (18 or 32 mg/L plus the required amount to oxidize all wine SO 2 ). In each oxygen level, 2-4 independent segments following pseudo-first order kinetics were identified, plus an initial segment at which wine consumed O 2 very fast. Overall, multivariate data techniques identify six different Oxygen-Consumption-Rates (OCRs) as required to completely define wine O 2 consumption. Except the last one, all could be modeled from the wine initial chemical composition. Total acetaldehyde, Mn, Cu/Fe, blue and red pigments and gallic acid seem to be essential to determine these OCRs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Diffusion and Monod kinetics model to determine in vivo human corneal oxygen-consumption rate during soft contact lens wear

    Directory of Open Access Journals (Sweden)

    Luis F. Del Castillo

    2015-01-01

    Conclusion: Present results are relevant for the calculation on the partial pressure of oxygen, available at different depths into the corneal tissue behind contact lenses of different oxygen transmissibility.

  3. Cellular respiration, oxygen consumption, and trade-offs of the jellyfish Cassiopea sp. in response to temperature change

    Science.gov (United States)

    Aljbour, Samir M.; Zimmer, Martin; Kunzmann, Andreas

    2017-10-01

    Pelagic jellyfish blooms are increasing worldwide as a potential response to climate-change. However, virtually nothing is known about physiological responses of jellyfish to e.g. sudden changes in water temperature due to extreme weather events. When confronted with a sudden decrease or increase in water temperature by 6 °C, medusae of Cassiopea sp. exhibited a strong response in locomotor activity (i.e., bell pulsation increased and decreased by ca. 37 and 46% in hot and cold acute (2 h) treatments, respectively) relative to control. Although medusae significantly gained in body mass (wet weight) upon chronic (2 weeks) heat treatment, their body size (e.g., bell diameter) did not change over this time interval. In contrast, chronic cold treatment resulted in both significant shrinking (reduced diameter) and mass loss. Measurements of mitochondrial electron transport system (ETS) activities and rate of respiratory oxygen uptake (MO2) are good estimates of energy consumption and the potential aerobic metabolic rates of an organism. While both acute treatments significantly increased ETS-activities, acclimation over two weeks resulted in a drop in activities to the control levels. Whereas acute heat treatment significantly increased MO2, chronic exposure resulted in significant MO2 decrease compared to control; however no changes in MO2 could be observed in both acute and chronic cold treatments. Overall these results suggest an enhanced growth in response to global warming, whereas low temperatures may set the limits for successful invasion of Cassiopea into colder water bodies. Our results provide a framework for understanding the physiological tolerance of Cassiopea under possible future climate changes.

  4. Simultaneous evaluation of substrate-dependent oxygen consumption rates and mitochondrial membrane potential by TMRM and safranin in cortical mitochondria.

    Science.gov (United States)

    Chowdhury, Subir Roy; Djordjevic, Jelena; Albensi, Benedict C; Fernyhough, Paul

    2015-12-08

    Mitochondrial membrane potential (mtMP) is critical for maintaining the physiological function of the respiratory chain to generate ATP. The present study characterized the inter-relationship between mtMP, using safranin and tetramethyl rhodamine methyl ester (TMRM), and mitochondrial respiratory activity and established a protocol for functional analysis of mitochondrial bioenergetics in a multi-sensor system. Coupled respiration was decreased by 27 and 30-35% in the presence of TMRM and safranin respectively. Maximal respiration was higher than coupled with Complex I- and II-linked substrates in the presence of both dyes. Safranin showed decreased maximal respiration at a higher concentration of carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone (FCCP) compared with TMRM. FCCP titration revealed that maximal respiration in the presence of glutamate and malate was not sustainable at higher FCCP concentrations as compared with pyruvate and malate. Oxygen consumption rate (OCR) and mtMP in response to mitochondrial substrates were higher in isolated mitochondria compared with tissue homogenates. Safranin exhibited higher sensitivity to changes in mtMP than TMRM. This multi-sensor system measured mitochondrial parameters in the brain of transgenic mice that model Alzheimer's disease (AD), because mitochondrial dysfunction is believed to be a primary event in the pathogenesis of AD. The coupled and maximal respiration of electron transport chain were decreased in the cortex of AD mice along with the mtMP compared with age-matched controls. Overall, these data demonstrate that safranin and TMRM are suitable for the simultaneous evaluation of mtMP and respiratory chain activity using isolated mitochondria and tissue homogenate. However, certain care should be taken concerning the selection of appropriate substrates and dyes for specific experimental circumstances. © 2016 Authors.

  5. High- and moderate-intensity aerobic exercise and excess post-exercise oxygen consumption in men with metabolic syndrome.

    Science.gov (United States)

    Larsen, I; Welde, B; Martins, C; Tjønna, A E

    2014-06-01

    Physical activity is central in prevention and treatment of metabolic syndrome. High-intensity aerobic exercise can induce larger energy expenditure per unit of time compared with moderate-intensity exercise. Furthermore, it may induce larger energy expenditure at post-exercise recovery. The aim of this study is to compare the excess post-exercise oxygen consumption (EPOC) in three different aerobic exercise sessions in men with metabolic syndrome. Seven men (age: 56.7 ± 10.8) with metabolic syndrome participated in this crossover study. The sessions consisted of one aerobic interval (1-AIT), four aerobic intervals (4-AIT), and 47-min continuous moderate exercise (CME) on separate days, with at least 48 h between each test day. Resting metabolic rate (RMR) was measured pre-exercise and used as baseline value. EPOC was measured until baseline metabolic rate was re-established. An increase in O2 uptake lasting for 70.4 ± 24.8 min (4-AIT), 35.9 ± 17.3 min (1-AIT), and 45.6 ± 17.3 min (CME) was observed. EPOC were 2.9 ± 1.7 L O2 (4-AIT), 1.3 ±  .1 L O2 (1-AIT), and 1.4 ± 1.1 L O2 (CME). There were significant differences (P exercise intensity has a significant positive effect on EPOC in men with metabolic syndrome. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Temperature effect on behaviour, oxygen consumption, ammonia excretion and tolerance limit of the post larvae of shrimp Penaeus indicus.

    Science.gov (United States)

    Krishnamoorthy, R; Mohamed, E H Syed; Rao, T Subba; Venugopalanj, V P; Hameed, P Shahul

    2008-01-01

    The present study has been carried out to know the effect of temperature on behaviour, equilibrium loss and tolerance limit of the post larvae of shrimp Penaeus indicus. The experimental temperatures were selected based on the thermal tolerance limit. The experiments were conducted at a specific temperature for duration of 48 hr. The thermal tolerance experiments were conducted in two ways: in direct exposure and in gradually increasing temperature. The upper and lower lethal temperatures for the post larvae of shrimp P. indicus were 43.5 degrees C and 8 degrees C respectively. During tolerance experiment, no mortality was observed at 33 degrees C and 35 degrees C. But at 38 degrees C with gradual increase in temperature, 30% loss of equilibrium and mortality were recorded in 24.31 hrs and 25.07 hrs, and the remaining 70% were alive. On the contrary, when the post larvae of shrimps were directly exposed to 38 degrees C, almost 80% loss of equilibrium and mortality were recorded in 30.22 hrs and 30.40 hrs, remaining 20% were alive. At 40 degrees C with gradual increase in temperature, 100% loss of equilibrium and mortality were recorded in 25.32 hrs and 25.56 hrs. On the other hand, when the post larvae of shrimps were directly exposed to 40 degrees C, 100% loss of equilibrium was observed in 0.37 hrs and mortality in 1.40 hrs. These behavioral responses include an elevated temperature of 12 degrees C, surfacing, dashing against glass wall, jumping out of the water, etc. In general, the rate of oxygen consumption and ammonia excretion was found to enhance with increasing temperature. In the present study, it was found that gradual increase in temperature favours the shellfish population to escape from the thermal exposure as compared to direct exposure.

  7. Acute effect of ivabradine on heart rate and myocardial oxygen consumption in dogs with asymptomatic mitral valve degeneration.

    Science.gov (United States)

    Pirintr, Prapawadee; Limprasutr, Vudhiporn; Saengklub, Nakkawee; Pavinadol, Parnpradub; Yapao, Napat; Limvanicharat, Natthakarn; Kuecharoen, Hathaisiri; Kijtawornrat, Anusak

    2018-05-14

    Degenerative mitral valve disease (DMVD) is a common cardiac disease in geriatric dogs characterized by the degeneration of the mitral valve, leading to decreased cardiac output and activation of the sympathetic and renin-angiotensin-aldosterone system. This disease results in an increased resting heart rate (HR) and myocardial oxygen consumption (MVO 2 ). A recent publication demonstrated that dogs with asymptomatic DMVD had a significantly higher HR and systemic blood pressure (BP) than age-matched control dogs. This higher HR will eventually contribute to increased MVO 2 . This study aimed to determine the effects of a single oral dose of ivabradine on the HR, MVO 2 as assessed by the rate-pressure product, and BP in dogs with asymptomatic DMVD. Seven beagles with naturally occurring DMVD were instrumented by the Holter recorder and an oscillometric device to measure electrocardiogram and BP for 24 and 12 h, respectively. Each dog was randomly subjected to receive either placebo or ivabradine (0.5, 1.0 and 2.0 mg/kg). The results revealed that oral administration of ivabradine significantly decreased the HR and rate-pressure product in a dose-dependent manner without adverse effects. The highest dose of 2.0 mg/kg significantly reduced systolic and mean BP. Therefore, the findings imply that a single oral ivabradine administration at a dose of 1.0 mg/kg is suitable for dogs with asymptomatic DMVD to reduce the HR and MVO 2 without marked effects on BP. This may potentially make ivabradine promising for management of an elevated HR in DMVD dogs.

  8. Influence of different production strategies on the stability of color, oxygen consumption and metmyoglobin reducing activity of meat from Ningxia Tan sheep.

    Science.gov (United States)

    Gao, Xiaoguang; Wang, Zhenyu; Miao, Jing; Xie, Li; Dai, Yan; Li, Xingmin; Chen, Yong; Luo, Hailing; Dai, Ruitong

    2014-02-01

    Fifty male Ningxia Tan sheep were randomly divided into five groups (10 per group). Different feeding strategies were applied to each group for 120 days prior to slaughter. The sheep belong to five groups were pastured for 0 h (feedlot-fed), 2h, 4h, 8h, 12h per day on a natural grazing ground, respectively. M. semitendinosus muscle from Tan sheep was obtained after slaughter. Instrumental color, pH values, oxygen consumption rate, metmyoglobin reducing activity and relative metmyoglobin percentages were analyzed after 1, 3, 5, 7 and 9 days of refrigerated storage. Long-term daily grazing and herbage-based diet were conducive to maintain a lower oxygen consumption rate, higher metmyoglobin reducing activity and lower metmyoglobin accumulation. The combination of pasture-fed and feedlot-fed was conducive to weight gain, and at the same time, increased the color stability of the meat from Ningxia Tan sheep. © 2013.

  9. Energy savings in sea bass swimming in a school: measurements of tail beat frequency and oxygen consumption at different swimming speeds

    DEFF Research Database (Denmark)

    Herskin, J; Steffensen, JF

    1998-01-01

    Tail beat frequency of sea bass, Dicentrarchus labrax (L.) (23.5 ± 0·5 cm, LT), swimming at the front of a school was significantly higher than when swimming at the rear, for all water velocities tested from 14·8 to 32 cm s-1. The logarithm of oxygen consumption rate, and the tail beat frequency...... of solitary swimming sea bass (28·8 ± 0·4 cm, LT), were each correlated linearly with swimming speed, and also with one another. The tail beat frequency of individual fish was 9-14% lower when at the rear of a school than when at the front, corresponding to a 9-23% reduction in oxygen consumption rate....

  10. Wii, Kinect, and Move. Heart Rate, Oxygen Consumption, Energy Expenditure, and Ventilation due to Different Physically Active Video Game Systems in College Students

    OpenAIRE

    SCHEER, KRISTA S.; SIEBRANT, SARAH M.; BROWN, GREGORY A.; SHAW, BRANDON S.; SHAW, INA

    2014-01-01

    Nintendo Wii, Sony Playstation Move, and Microsoft XBOX Kinect are home video gaming systems that involve player movement to control on-screen game play. Numerous investigations have demonstrated that playing Wii is moderate physical activity at best, but Move and Kinect have not been as thoroughly investigated. The purpose of this study was to compare heart rate, oxygen consumption, and ventilation while playing the games Wii Boxing, Kinect Boxing, and Move Gladiatorial Combat. Heart rate, o...

  11. Bio-filtration capacity, oxygen consumption and ammonium excretion of Dosinia ponderosa and Chione gnidia (Veneroida: Veneridae) from areas impacted and non-impacted by shrimp aquaculture effluents.

    Science.gov (United States)

    Ramos-Corella, Karime; Martínez-Córdova, Luis Rafael; Enríquez-Ocaña, Luis Fernando; Miranda-Baeza, Anselmo; López-Elías, José Antonio

    2014-09-01

    Mollusks are some of the most important, abundant and diverse organisms inhabiting not only aquatic ecosystems, but also terrestrial environments. Recently, they have been used for bioremediation of aquaculture effluents; nevertheless, for that purpose it is necessary to analyze the capacity of a particular species. In this context, an experimental investigation was developed to evaluate the performance of two bivalves C. gnidia and D. ponderosa, collected from areas with or without shrimp aquaculture effluents. For this, the filtration capacity (as clearance rate) as well as the oxygen consumption and ammonia excretion rates were measured following standard methods. The clearance rate was significantly higher for D. ponderosa from impacted areas, when com- pared to C. gnidia, from both areas. Contrarily, the oxygen consumption was greater for C. gnidia from impacted areas compared to D. ponderosa from both areas. The same tendency was observed for the ammonia excretion with the highest rates observed for C. gnidia from impacted areas, whereas no differences were observed among D. ponderosa from both areas. The results suggest that both species developed different strategies to thrive and survive under the impacted conditions; D. ponderosa improved its filtration efficiency, while C. gnidia modified its oxygen consumption and ammonia excretion. We concluded that both species, and particularly D. ponderosa, can be used for bioremediation purposes.

  12. Bio-filtration capacity, oxygen consumption and ammonium excretion of Dosinia ponderosa and Chione gnidia (Veneroida: Veneridae from areas impacted and non-impacted by shrimp aquaculture effluents

    Directory of Open Access Journals (Sweden)

    Karime Ramos-Corella

    2014-09-01

    Full Text Available Mollusks are some of the most important, abundant and diverse organisms inhabiting not only aquatic ecosystems, but also terrestrial environments. Recently, they have been used for bioremediation of aquaculture effluents; nevertheless, for that purpose it is necessary to analyze the capacity of a particular species. In this context, an experimental investigation was developed to evaluate the performance of two bivalves C. gnidia and D. ponderosa, collected from areas with or without shrimp aquaculture effluents. For this, the filtration capacity (as clearance rate as well as the oxygen consumption and ammonia excretion rates were measured following standard methods. The clearance rate was significantly higher for D. ponderosa from impacted areas, when com- pared to C. gnidia, from both areas. Contrarily, the oxygen consumption was greater for C. gnidia from impacted areas compared to D. ponderosa from both areas. The same tendency was observed for the ammonia excretion with the highest rates observed for C. gnidia from impacted areas, whereas no differences were observed among D. ponderosa from both areas. The results suggest that both species developed different strategies to thrive and survive under the impacted conditions; D. ponderosa improved its filtration efficiency, while C. gnidia modified its oxygen consumption and ammonia excretion. We concluded that both species, and particularly D. ponderosa, can be used for bioremediation purposes.

  13. Duration of effects of acute environmental changes on food anticipatory behaviour, feed intake, oxygen consumption, and cortisol release in Atlantic salmon parr.

    Science.gov (United States)

    Folkedal, Ole; Torgersen, Thomas; Olsen, Rolf Erik; Fernö, Anders; Nilsson, Jonatan; Oppedal, Frode; Stien, Lars H; Kristiansen, Tore S

    2012-01-18

    We compared behavioural and physiological responses and recovery time after different acute environmental challenges in groups of salmon parr. The fish were prior to the study conditioned to a flashing light signalling arrival of food 30 s later to study if the strength of Pavlovian conditioned food anticipatory behaviour can be used to assess how salmon parr cope with various challenges. The effect on anticipatory behaviour was compared to the effect on feed intake and physiological responses of oxygen hyper-consumption and cortisol excretion. The challenges were temperature fluctuation (6.5C° over 4 h), hyperoxia (up to 380% O(2) saturation over 4 h), and intense chasing for 10 min. Cortisol excretion was only elevated after hyperoxia and chasing, and returned to baseline levels after around 3 h or less. Oxygen hyper-consumption persisted for even shorter periods. Feed intake was reduced the first feeding after all challenges and recovered within 3 h after temperature and hyperoxia, but was reduced for days after chasing. Food anticipatory behaviour was reduced for a longer period than feed intake after hyperoxia and was low at least 6 h after chasing. Our findings suggest that a recovery of challenged Atlantic salmon parr to baseline levels of cortisol excretion and oxygen consumption does not mean full recovery of all psychological and physiological effects of environmental challenges, and emphasise the need for measuring several factors including behavioural parameters when assessing fish welfare. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. Maximal exercise test is a useful method for physical capacity and oxygen consumption determination in streptozotocin-diabetic rats

    Directory of Open Access Journals (Sweden)

    Irigoyen Maria-Cláudia

    2007-12-01

    Full Text Available Abstract Background The aim of the present study was to investigate the relationship between speed during maximum exercise test (ET and oxygen consumption (VO2 in control and STZ-diabetic rats, in order to provide a useful method to determine exercise capacity and prescription in researches involving STZ-diabetic rats. Methods Male Wistar rats were divided into two groups: control (CG, n = 10 and diabetic (DG, n = 8. The animals were submitted to ET on treadmill with simultaneous gas analysis through open respirometry system. ET and VO2 were assessed 60 days after diabetes induction (STZ, 50 mg/Kg. Results VO2 maximum was reduced in STZ-diabetic rats (72.5 ± 1 mL/Kg/min-1 compared to CG rats (81.1 ± 1 mL/Kg/min-1. There were positive correlations between ET speed and VO2 (r = 0.87 for CG and r = 0.8 for DG, as well as between ET speed and VO2 reserve (r = 0.77 for CG and r = 0.7 for DG. Positive correlations were also obtained between measured VO2 and VO2 predicted values (r = 0.81 for CG and r = 0.75 for DG by linear regression equations to CG (VO2 = 1.54 * ET speed + 52.34 and DG (VO2 = 1.16 * ET speed + 51.99. Moreover, we observed that 60% of ET speed corresponded to 72 and 75% of VO2 reserve for CG and DG, respectively. The maximum ET speed was also correlated with VO2 maximum for both groups (CG: r = 0.7 and DG: r = 0.7. Conclusion These results suggest that: a VO2 and VO2 reserve can be estimated using linear regression equations obtained from correlations with ET speed for each studied group; b exercise training can be prescribed based on ET in control and diabetic-STZ rats; c physical capacity can be determined by ET. Therefore, ET, which involves a relatively simple methodology and low cost, can be used as an indicator of cardio-respiratory capacity in future studies that investigate the physiological effect of acute or chronic exercise in control and STZ-diabetic male rats.

  15. Maximal exercise test is a useful method for physical capacity and oxygen consumption determination in streptozotocin-diabetic rats

    Science.gov (United States)

    Rodrigues, Bruno; Figueroa, Diego M; Mostarda, Cristiano T; Heeren, Marcelo V; Irigoyen, Maria-Cláudia; De Angelis, Kátia

    2007-01-01

    Background The aim of the present study was to investigate the relationship between speed during maximum exercise test (ET) and oxygen consumption (VO2) in control and STZ-diabetic rats, in order to provide a useful method to determine exercise capacity and prescription in researches involving STZ-diabetic rats. Methods Male Wistar rats were divided into two groups: control (CG, n = 10) and diabetic (DG, n = 8). The animals were submitted to ET on treadmill with simultaneous gas analysis through open respirometry system. ET and VO2 were assessed 60 days after diabetes induction (STZ, 50 mg/Kg). Results VO2 maximum was reduced in STZ-diabetic rats (72.5 ± 1 mL/Kg/min-1) compared to CG rats (81.1 ± 1 mL/Kg/min-1). There were positive correlations between ET speed and VO2 (r = 0.87 for CG and r = 0.8 for DG), as well as between ET speed and VO2 reserve (r = 0.77 for CG and r = 0.7 for DG). Positive correlations were also obtained between measured VO2 and VO2 predicted values (r = 0.81 for CG and r = 0.75 for DG) by linear regression equations to CG (VO2 = 1.54 * ET speed + 52.34) and DG (VO2 = 1.16 * ET speed + 51.99). Moreover, we observed that 60% of ET speed corresponded to 72 and 75% of VO2 reserve for CG and DG, respectively. The maximum ET speed was also correlated with VO2 maximum for both groups (CG: r = 0.7 and DG: r = 0.7). Conclusion These results suggest that: a) VO2 and VO2 reserve can be estimated using linear regression equations obtained from correlations with ET speed for each studied group; b) exercise training can be prescribed based on ET in control and diabetic-STZ rats; c) physical capacity can be determined by ET. Therefore, ET, which involves a relatively simple methodology and low cost, can be used as an indicator of cardio-respiratory capacity in future studies that investigate the physiological effect of acute or chronic exercise in control and STZ-diabetic male rats. PMID:18078520

  16. Changes in the lipid composition of blood under the influence of a single submaximal exercise capacity (experimental research.

    Directory of Open Access Journals (Sweden)

    Ermolaeva E.N.

    2015-06-01

    Full Text Available In acute physical exercise, there is a change in oxygen delivery working tissues, blood gas transport function and efficiency of the use of oxygen by cells in the process of metabolism, which is the basis for compensation for physical activities. Lipid metabolism plays an important role in the energy supply of muscle activity. The aim of our research is to study the effect of a single submaximal exercise capacity by changing the lipid profile of peripheral blood. Materials and Methods. The study was performed on 18 white rats. Model of acute exercise: animals swam 4 minutes with a load weighing 20% of body weight. Blood sampling was performed by intracardiac way, right after exercise. The blood lipid profile was determined. Results. In the experiment reported an increase in triglycerides, total cholesterol, very low-density lipoproteins, but the atherogenic ratio is maintained at the control values, due to a significant increase in the level of high-density lipoprotein. Conclusion. Acute submaximal exercise capacity by untrained body has an atherogenic effect. Working muscles during physical activity is a major consumer of free fatty acids, which are the source of atherogenic lipoprotein form of the very low and low density.

  17. Differential Effects of Temperature on Oxygen Consumption and Branchial Fluxes of Urea, Ammonia, and Water in the Dogfish Shark (Squalus acanthias suckleyi).

    Science.gov (United States)

    Giacomin, Marina; Schulte, Patricia M; Wood, Chris M

    Environmental temperature can greatly influence the homeostasis of ectotherms through its effects on biochemical reactions and whole-animal physiology. Elasmobranchs tend to be N limited and are osmoconformers, retaining ammonia and urea-N at the gills and using the latter as a key osmolyte to maintain high blood osmolality. However, the effects of temperature on these key processes remain largely unknown. We evaluated the effects of acute exposure to different temperatures (7°, 12°, 15°, 18°, 22°C) on oxygen consumption, ammonia, urea-N, and diffusive water fluxes at the gills of Squalus acanthias suckleyi. We hypothesized that as metabolic demand for oxygen increased with temperature, the fluxes of ammonia, urea-N, and 3 H 2 O at the gills would increase in parallel with those of oxygen. Oxygen consumption (overall [Formula: see text] from 7.5° to 22°C) and water fluxes (overall [Formula: see text]) responded to increases in temperature in a similar, almost linear, manner. Ammonia-N efflux rates varied the most, increasing almost 15-fold from 7.5° to 22°C ([Formula: see text]). Urea-N efflux was tightly conserved over the 7.5°-15°C range ([Formula: see text]) but increased greatly at higher temperatures, yielding an overall [Formula: see text]. These differences likely reflect differences in the transport pathways for the four moieties. They also suggest the failure of urea-N- and ammonia-N-conserving mechanisms at the gill above 15°C. Hyperoxia did not alleviate the effects of high temperature. Indeed, urea-N and ammonia-N effluxes were dramatically increased when animals were exposed to high temperatures in the presence of hyperoxia, suggesting that high partial pressure of oxygen may have caused oxidative damage to gill epithelial membranes.

  18. Oxygen and coke oven gas (COG) consumption optimization at hot stove of Usiminas blast furnace 3; Otimizacao do consumo de oxigenio e GCO nos regeneradores do alto forno 3 da Usiminas

    Energy Technology Data Exchange (ETDEWEB)

    Cervino, Marco Antonio; Bastos, Moises Hofer [Usiminas, Ipatinga, MG (Brazil)

    2001-07-01

    This paper presents the model developed for determination of the correlation between oxygen and coke oven gas (COG) consumption in the hot stove at Usiminas blast furnace 3, the applicability and results obtained. (author)

  19. Whole-body pre-cooling does not alter human muscle metabolism during sub-maximal exercise in the heat.

    Science.gov (United States)

    Booth, J; Wilsmore, B R; Macdonald, A D; Zeyl, A; Mcghee, S; Calvert, D; Marino, F E; Storlien, L H; Taylor, N A

    2001-06-01

    Muscle metabolism was investigated in seven men during two 35 min cycling trials at 60% peak oxygen uptake, at 35 degrees C and 50% relative humidity. On one occasion, exercise was preceded by whole-body cooling achieved by immersion in water during a reduction in temperature from 29 to 24 degrees C, and, for the other trial, by immersion in water at a thermoneutral temperature (control, 34.8 degrees C). Pre-cooling did not alter oxygen uptake during exercise (P > 0.05), whilst the change in cardiac frequency and body mass both tended to be lower following pre-cooling (0.05 whole-body pre-cooling does not alter muscle metabolism during submaximal exercise in the heat. It is more likely that thermoregulatory and cardiovascular strain are reduced, through lower muscle and core temperatures.

  20. Cardiac Autonomic Function during Submaximal Treadmill Exercise in Adults with Down Syndrome

    Science.gov (United States)

    Mendonca, Goncalo V.; Pereira, Fernando D.; Fernhall, Bo

    2011-01-01

    This study determined whether the cardiac autonomic function of adults with Down syndrome (DS) differs from that of nondisabled persons during submaximal dynamic exercise. Thirteen participants with DS and 12 nondisabled individuals performed maximal and submaximal treadmill tests with metabolic and heart rate (HR) measurements. Spectral analysis…

  1. Diurnal dynamics of oxygen and carbon dioxide concentrations in shoots and rhizomes of a perennial in a constructed wetland indicate down-regulation of below ground oxygen consumption

    Czech Academy of Sciences Publication Activity Database

    Fausser, A. C.; Dušek, Jiří; Čížková, Hana; Kazda, M.

    2016-01-01

    Roč. 8, JUL (2016), č. článku plw025. ISSN 2041-2851 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA MŠk(CZ) LM2010007 Institutional support: RVO:86652079 Keywords : typha-latifolia l * internal gas-transport * phragmites-australis * convective throughflow * pressurized ventilation * angustifolia l * ex steud * roots * flow * respiration * Aeration * constructed wetland * in-situ field study * internal carbon dioxide * internal oxygen dynamics * Phragmites australis Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 2.238, year: 2016

  2. Metabolic adaptations may counteract ventilatory adaptations of intermittent hypoxic exposure during submaximal exercise at altitudes up to 4000 m.

    Directory of Open Access Journals (Sweden)

    Martin Faulhaber

    Full Text Available Intermittent hypoxic exposure (IHE has been shown to induce aspects of altitude acclimatization which affect ventilatory, cardiovascular and metabolic responses during exercise in normoxia and hypoxia. However, knowledge on altitude-dependent effects and possible interactions remains scarce. Therefore, we determined the effects of IHE on cardiorespiratory and metabolic responses at different simulated altitudes in the same healthy subjects. Eight healthy male volunteers participated in the study and were tested before and 1 to 2 days after IHE (7 × 1 hour at 4500 m. The participants cycled at 2 submaximal workloads (corresponding to 40% and 60% of peak oxygen uptake at low altitude at simulated altitudes of 2000 m, 3000 m, and 4000 m in a randomized order. Gas analysis was performed and arterial oxygen saturation, blood lactate concentrations, and blood gases were determined during exercise. Additionally baroreflex sensitivity, hypoxic and hypercapnic ventilatory response were determined before and after IHE. Hypoxic ventilatory response was increased after IHE (p<0.05. There were no altitude-dependent changes by IHE in any of the determined parameters. However, blood lactate concentrations and carbon dioxide output were reduced; minute ventilation and arterial oxygen saturation were unchanged, and ventilatory equivalent for carbon dioxide was increased after IHE irrespective of altitude. Changes in hypoxic ventilatory response were associated with changes in blood lactate (r = -0.72, p<0.05. Changes in blood lactate correlated with changes in carbon dioxide output (r = 0.61, p<0.01 and minute ventilation (r = 0.54, p<0.01. Based on the present results it seems that the reductions in blood lactate and carbon dioxide output have counteracted the increased hypoxic ventilatory response. As a result minute ventilation and arterial oxygen saturation did not increase during submaximal exercise at simulated altitudes between 2000 m and 4000 m.

  3. Oxygen consumption remains stable while ammonia excretion is reduced upon short time exposure to high salinity in Macrobrachium acanthurus (Caridae: Palaemonidae, a recent freshwater colonizer

    Directory of Open Access Journals (Sweden)

    Carolina A. Freire

    2017-10-01

    Full Text Available ABSTRACT Palaemonid shrimps occur in the tropical and temperate regions of South America and the Indo-Pacific, in brackish/freshwater habitats, and marine coastal areas. They form a clade that recently (i.e., ~30 mya invaded freshwater, and one included genus, Macrobrachium Bate, 1868, is especially successful in limnic habitats. Adult Macrobrachium acanthurus (Wiegmann, 1836 dwell in coastal freshwaters, have diadromous habit, and need brackish water to develop. Thus, they are widely recognized as euryhaline. Here we test how this species responds to a short-term exposure to increased salinity. We hypothesized that abrupt exposure to high salinity would result in reduced gill ventilation/perfusion and decreased oxygen consumption. Shrimps were subjected to control (0 psu and experimental salinities (10, 20, 30 psu, for four and eight hours (n = 8 in each group. The water in the experimental containers was saturated with oxygen before the beginning of the experiment; aeration was interrupted before placing the shrimp in the experimental container. Dissolved oxygen (DO, ammonia concentration, and pH were measured from the aquaria water, at the start and end of each experiment. After exposure, the shrimp’s hemolymph was sampled for lactate and osmolality assays. Muscle tissue was sampled for hydration content (Muscle Water Content, MWC. Oxygen consumption was not reduced and hemolymph lactate did not increase with increased salinity. The pH of the water decreased with time, under all conditions. Ammonia excretion decreased with increased salinity. Hemolymph osmolality and MWC remained stable at 10 and 20 psu, but osmolality increased (~50% and MWC decreased (~4% at 30 psu. The expected reduction in oxygen consumption was not observed. This shrimp is able to tolerate significant changes in water salt concentrations for a few hours by keeping its metabolism in aerobic mode, and putatively shutting down branchial salt uptake to avoid massive salt

  4. Determination of relative CMRO2 from CBF and BOLD changes: significant increase of oxygen consumption rate during visual stimulation

    DEFF Research Database (Denmark)

    Kim, S.G.; Rostrup, Egill; Larsson, H.B.

    1999-01-01

    signal changes were measured simultaneously using the flow-sensitive alternating inversion recovery (FAIR) technique. During hypercapnia established by an end-tidal CO2 increase of 1.46 kPa, CBF in the visual cortex increased by 47.3 +/- 17.3% (mean +/- SD; n = 9), and deltaR2* was -0.478 +/- 0.147 sec......The blood oxygenation level-dependent (BOLD) effect in functional magnetic resonance imaging depends on at least partial uncoupling between cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) changes. By measuring CBF and BOLD simultaneously, the relative change in CMRO2 can...

  5. Activity-dependent increases in local oxygen consumption correlate with postsynaptic currents in the mouse cerebellum in vivo

    DEFF Research Database (Denmark)

    Mathiesen, Claus; Caesar, Kirsten; Thomsen, Kirsten Engelund

    2011-01-01

    Evoked neural activity correlates strongly with rises in cerebral metabolic rate of oxygen (CMRO(2)) and cerebral blood flow (CBF). Activity-dependent rises in CMRO(2) fluctuate with ATP turnover due to ion pumping. In vitro studies suggest that increases in cytosolic Ca(2+) stimulate oxidative m...

  6. Activity-dependent increases in local oxygen consumption correlate with post-synaptic currents in the mouse cerebellum in vivo

    DEFF Research Database (Denmark)

    Mathiesen, Claus; Caesar, Kirsten; Thomsen, Kirsten Joan

    2011-01-01

    Evoked neural activity correlates strongly with rises in cerebral metabolic rate of oxygen (CMRO2) and cerebral blood flow. Activity-dependent rises in CMRO2 fluctuate with ATP turnover due to ion pumping. In vitro studies suggest that increases in cytosolic Ca2+ stimulate oxidative metabolism vi...

  7. Hypoxia, but not an electrolyte-imbalanced diet, reduces feed intake, growth and oxygen consumption in rainbow trout (Oncorhynchus mykiss)

    NARCIS (Netherlands)

    Magnoni, Leonardo J.; Eding, Ep; Leguen, Isabelle; Prunet, Patrick; Geurden, Inge; Ozório, Rodrigo O.A.; Schrama, Johan W.

    2018-01-01

    Oxygen limitation and dietary imbalances are key aspects influencing feed intake (FI) and growth performance in cultured fish. This study investigated the combined effects of hypoxia and dietary electrolyte balance on the growth performance, body composition and nutrient utilization in a rainbow

  8. Effects of ozone on adult and aged lung oxygen consumption, glucose metabolism and G6PDH activity

    International Nuclear Information System (INIS)

    Raska-Emery, P.; Balis, J.U.; Montgomery, M.R.

    1991-01-01

    Fischer-344 male adult (4-6 mo) and aged (24-26 mo) rats were exposed to 0-3.0 ppm O 3 for 8h, sacrificed immediately, and O 2 consumption, 1 C 14 -glucose metabolism and G6PDH activity were determined. For O 2 consumption, the exp to 0.5 ppm O 3 produced a stimulation in both age groups. Decrements in O 2 consumption were only evident in aged rats after 1.5 and 3.0 ppm. Glucose metabolism showed a marked difference rats were 40% adult rats. Control values in aged rats were 40% of adults. Exp to 0.5 ppm was stimulatory in adults and aged, while 1.5 and 3.0 pp, decreased glucose metabolism in both groups. No age-related difference in G6PDH activity between control and exposed was seen. However, in both age groups, 0.5 ppm O 3 resulted in a significant increase in activity (33-41%)l 1.5 and 3.0 ppm were without effect. The combined results show a biphasic response of adult and aged lung to severe, acute O 3 exp. One-half ppm O 3 for 8h is stimulatory for all three parameters examined in both age groups. Three ppm O 3 inhibits O 2 consumption and glucose metabolism in both age groups but is ineffective on G6PDH activity

  9. Evaluation of the effects of the metals Cd, Cr, Pb and their mixture on the filtration and oxygen consumption rates in catarina scallop, Argopecten ventricosus juveniles.

    Science.gov (United States)

    Sobrino-Figueroa, Alma S; Cáceres-Martinez, Carlos

    2014-01-01

    In this work, we evaluated the effect of sublethal concentrations ( LC25, LC10 and LC5) of cadmium, chromium, lead, and their mixture on the filtration rate and oxygen consumption rate of Catarina scallop, Argopecten ventricosus (Sowerby, 1842), juveniles, in order to evaluate the use of these biomarkers as a reliable tool in environmental monitoring studies, because these metals have been found at high levels in water and sediments in the Mexican Pacific systems. An inverse dose-response relationship was observed when metal concentration and exposure time increased, the filtration rate and oxygen consumption rate reduced. The physiological responses evaluated in this study were sufficiently sensitive to detect alterations in the organisms at 0.014 mg l(-1) Cd, 0.311 mg l(-1) Cr, 0.125 mg l(-1) Pb and 0.05 mg l(-1) Cd + Cr + Pb at 24 and 72 hrs. Cd showed the most drastic effect. The Catarina scallop juveniles were more sensitive to Cd, Cr and Pb as compared to other bivalves. The biomarkers evaluated are a reliable tool to carry out environmental monitoring studies.

  10. Correlating two-photon excited fluorescence imaging of breast cancer cellular redox state with seahorse flux analysis of normalized cellular oxygen consumption

    Science.gov (United States)

    Hou, Jue; Wright, Heather J.; Chan, Nicole; Tran, Richard; Razorenova, Olga V.; Potma, Eric O.; Tromberg, Bruce J.

    2016-06-01

    Two-photon excited fluorescence (TPEF) imaging of the cellular cofactors nicotinamide adenine dinucleotide and oxidized flavin adenine dinucleotide is widely used to measure cellular metabolism, both in normal and pathological cells and tissues. When dual-wavelength excitation is used, ratiometric TPEF imaging of the intrinsic cofactor fluorescence provides a metabolic index of cells-the "optical redox ratio" (ORR). With increased interest in understanding and controlling cellular metabolism in cancer, there is a need to evaluate the performance of ORR in malignant cells. We compare TPEF metabolic imaging with seahorse flux analysis of cellular oxygen consumption in two different breast cancer cell lines (MCF-7 and MDA-MB-231). We monitor metabolic index in living cells under both normal culture conditions and, for MCF-7, in response to cell respiration inhibitors and uncouplers. We observe a significant correlation between the TPEF-derived ORR and the flux analyzer measurements (R=0.7901, p<0.001). Our results confirm that the ORR is a valid dynamic index of cell metabolism under a range of oxygen consumption conditions relevant for cancer imaging.

  11. Muscle contraction duration and fibre recruitment influence blood flow and oxygen consumption independent of contractile work during steady-state exercise in humans.

    Science.gov (United States)

    Richards, Jennifer C; Crecelius, Anne R; Kirby, Brett S; Larson, Dennis G; Dinenno, Frank A

    2012-06-01

    We tested the hypothesis that, among conditions of matched contractile work, shorter contraction durations and greater muscle fibre recruitment result in augmented skeletal muscle blood flow and oxygen consumption ( ) during steady-state exercise in humans. To do so, we measured forearm blood flow (FBF; Doppler ultrasound) during 4 min of rhythmic hand-grip exercise in 24 healthy young adults and calculated forearm oxygen consumption ( ) via blood samples obtained from a catheter placed in retrograde fashion into a deep vein draining the forearm muscle. In protocol 1 (n = 11), subjects performed rhythmic isometric hand-grip exercise at mild and moderate intensities during conditions in which time-tension index (isometric analogue of work) was held constant but contraction duration was manipulated. In this protocol, shorter contraction durations led to greater FBF (184 ± 25 versus 164 ± 25 ml min(-1)) and (23 ± 3 versus 17 ± 2 ml min(-1); both P flow. Our collective data indicate that, among matched workloads, shorter contraction duration and greater muscle fibre recruitment augment FBF and during mild-intensity forearm exercise, and that muscle blood flow is more closely related to metabolic cost ( ) rather than contractile work per se during steady-state exercise in humans.

  12. Effect of thyroxine on cellular oxygen-consumption and glucose uptake: evidence of an effect of total T4 and not "free T4"

    DEFF Research Database (Denmark)

    Kvetny, J; Matzen, L E

    1990-01-01

    Recent studies of cellular T4 and T3 uptake have indicated active transport of the hormones into the cell rather than passive diffusion of the non-protein bound fraction. In order to study the significance of the extracellular environment, oxygen consumption and glucose uptake were examined...... in human mononuclear blood cells. Cells were incubated in protein free medium and in human serum totally depleted of thyroid hormones by resin treatment and fixed amounts of T4 (total T4 = 0-50-100-5000 nmol/l; free T4 = 0-5-11-5600 pmol/l) were added. Thyroxine stimulated glucose uptake and oxygen......-consumption in a dose dependent manner but the T4 stimulation was dependent on the total concentration of T4 and did not differ between serum incubation or non-protein containing medium. Addition of ANS (100 mg/l) which inhibits binding of T4 to TBG, did not increase T4 effect in serum. Inhibition of the Na...

  13. Consumo de oxigênio pós-prandial de juvenis do pampo Trachinotus marginatus Postprandial oxygen consumption of juvenile pompano Trachinotus marginatus

    Directory of Open Access Journals (Sweden)

    Viviana Lisboa Cunha

    2009-07-01

    Full Text Available Para determinar a viabilidade do cultivo de uma espécie, é importante o conhecimento dos fatores limitantes para sua produção. Conhecer a taxa de consumo de oxigênio pós-prandial pode auxiliar na determinação da freqüência alimentar ideal para as espécies cultivadas. O objetivo deste trabalho foi estudar a taxa de consumo de oxigênio pós-prandial para juvenis do pampo Trachinotus marginatus. A avaliação do consumo de oxigênio foi feita a 24°C e 33‰, com pampos (9,64±0,2g alimentados com 12% da biomassa por dia com dieta NRD INVE (59% proteína. Foi observado um pico de consumo de oxigênio 30min após a alimentação (1,06mgO2 g-1 h-1 e seu retorno ao nível de jejum (0,79mgO2 g-1 h-1 depois de decorridos mais 120min. A alimentação de juvenis de pampo pode ser realizada com uma freqüência de aproximadamente oito vezes por dia, pois a cada 2,5h a taxa de consumo de oxigênio já não mostra a elevação característica da fase pós-prandial, sugerindo que os processos de digestão e assimilação dos nutrientes estejam finalizados.In order to determine the viability of new species for aquaculture, it is important to know the limiting factors for its production. The knowledge about postprandial oxygen consumption of fish is useful to estimate the time for returning to appetite and allows to estimate the proper feeding frequency. The objective of this research was to study the postprandial oxygen consumption of juvenile pompano Trachinotus marginatus. Oxygen consumption rate was determined at 24°C and 33‰ and fish (9.64±0.2g were fed daily with 12% total of biomass NRD INVE diet (59% protein. Postprandial increase in oxygen consumption was observed 30min after feeding (1.06mgO2 g-1 h-1, and it returned to the routine metabolic rate (0.79mgO2 g-1 h-1 within the next 120min. According to these results, it seems appropriated to feed juvenile pompano 8 times per day, because every 2.5h the oxygen consumption rate declines to

  14. Automatic labeling method for injectable 15O-oxygen using hemoglobin-containing liposome vesicles and its application for measurement of brain oxygen consumption by PET

    International Nuclear Information System (INIS)

    Tiwari, Vijay Narayan; Kiyono, Yasushi; Kobayashi, Masato; Mori, Tetsuya; Kudo, Takashi; Okazawa, Hidehiko; Fujibayashi, Yasuhisa

    2010-01-01

    Introduction: The aim of this study was to develop an injectable 15 O-O 2 system using hemoglobin-containing vesicles (HbV), a type of artificial red blood cell, and to investigate the feasibility of 15 O 2 -labeled HbV ( 15 O 2 -HbV) to measure cerebral metabolic rate of oxygen (CMRO 2 ) in rats. Methods: The direct bubbling method was combined with vortexing to enhance labeling efficiency of HbV with 15 O-O 2 gas. L-Cysteine was added as a reductant to protect hemoglobin molecules in HbV from oxidation at different concentrations, and labeling efficiencies were also compared. Measurement of cerebral blood flow (CBF) and CMRO 2 in five normal rats was performed using a small animal PET scanner after the injection of H 2 15 O and 15 O 2 -HbV to evaluate the precision of hemodynamic parameters quantitatively. Results: The labeling efficiency of HbV was significantly increased when vortexing and bubbling were combined compared with the simple bubbling method (P 15 O-O 2 combined with vortexing and the addition of 2.8 mM L-cysteine in HbV solution. The mean radioactivity of 214.4±7.8 MBq/mL HbV was obtained using this method. PET scans using 15 O 2 -HbV and H 2 15 O yielded a mean CMRO 2 value of 6.8±1.4 (mL/min per 100 g) in rats with normal CBF of 51.4±7.9 (mL/min per 100 g). Conclusion: Addition of L-cysteine to HbV and simple direct bubbling of 15 O-O 2 gas combined with vortexing was the most efficient method for preparation of 15 O 2 -HbV. The present injectable system using 15 O 2 -HbV was successfully utilized to measure CMRO 2 in rats, indicating that this new method could be useful for animal models to measure oxygen metabolism in the brain.

  15. Automatic labeling method for injectable {sup 15}O-oxygen using hemoglobin-containing liposome vesicles and its application for measurement of brain oxygen consumption by PET

    Energy Technology Data Exchange (ETDEWEB)

    Tiwari, Vijay Narayan [Biomedical Imaging Research Center, University of Fukui, Fukui (Japan)], E-mail: tiwaridr@u-fukui.ac.jp; Kiyono, Yasushi; Kobayashi, Masato; Mori, Tetsuya; Kudo, Takashi [Biomedical Imaging Research Center, University of Fukui, Fukui (Japan); Okazawa, Hidehiko [Biomedical Imaging Research Center, University of Fukui, Fukui (Japan); Research and Education Program for Life Science, University of Fukui, Fukui (Japan); Fujibayashi, Yasuhisa [Biomedical Imaging Research Center, University of Fukui, Fukui (Japan); Research and Education Program for Life Science, University of Fukui, Fukui (Japan)], E-mail: yfuji@u-fukui.ac.jp

    2010-01-15

    Introduction: The aim of this study was to develop an injectable {sup 15}O-O{sub 2} system using hemoglobin-containing vesicles (HbV), a type of artificial red blood cell, and to investigate the feasibility of {sup 15}O{sub 2}-labeled HbV ({sup 15}O{sub 2}-HbV) to measure cerebral metabolic rate of oxygen (CMRO{sub 2}) in rats. Methods: The direct bubbling method was combined with vortexing to enhance labeling efficiency of HbV with {sup 15}O-O{sub 2} gas. L-Cysteine was added as a reductant to protect hemoglobin molecules in HbV from oxidation at different concentrations, and labeling efficiencies were also compared. Measurement of cerebral blood flow (CBF) and CMRO{sub 2} in five normal rats was performed using a small animal PET scanner after the injection of H{sub 2}{sup 15}O and {sup 15}O{sub 2}-HbV to evaluate the precision of hemodynamic parameters quantitatively. Results: The labeling efficiency of HbV was significantly increased when vortexing and bubbling were combined compared with the simple bubbling method (P<.05). The most efficient method for labeling was bubbling of {sup 15}O-O{sub 2} combined with vortexing and the addition of 2.8 mM L-cysteine in HbV solution. The mean radioactivity of 214.4{+-}7.8 MBq/mL HbV was obtained using this method. PET scans using {sup 15}O{sub 2}-HbV and H{sub 2}{sup 15}O yielded a mean CMRO{sub 2} value of 6.8{+-}1.4 (mL/min per 100 g) in rats with normal CBF of 51.4{+-}7.9 (mL/min per 100 g). Conclusion: Addition of L-cysteine to HbV and simple direct bubbling of {sup 15}O-O{sub 2} gas combined with vortexing was the most efficient method for preparation of {sup 15}O{sub 2}-HbV. The present injectable system using {sup 15}O{sub 2}-HbV was successfully utilized to measure CMRO{sub 2} in rats, indicating that this new method could be useful for animal models to measure oxygen metabolism in the brain.

  16. Oxygen consumption rates in hovering hummingbirds reflect substrate-dependent differences in P/O ratios: carbohydrate as a 'premium fuel'.

    Science.gov (United States)

    Welch, Kenneth C; Altshuler, Douglas L; Suarez, Raul K

    2007-06-01

    The stoichiometric relationship of ATP production to oxygen consumption, i.e. the P/O ratio, varies depending on the nature of the metabolic substrate used. The latest estimates reveal a P/O ratio approximately 15% higher when glucose is oxidized compared with fatty acid oxidation. Because the energy required to produce aerodynamic lift for hovering is independent of the metabolic fuel oxidized, we hypothesized that the rate of oxygen consumption, VO2, should decline as the respiratory quotient, RQ (VCO2/VO2), increases from 0.71 to 1.0 as hummingbirds transition from a fasted to a fed state. Here, we show that hovering VO2 values in rufous (Selasphorus rufus) and Anna's hummingbirds (Calypte anna) are significantly greater when fats are metabolized (RQ=0.71) than when carbohydrates are used (RQ=1.0). Because hummingbirds gained mass during our experiments, making mass a confounding variable, we estimated VO2 per unit mechanical power output. Expressed in this way, the difference in VO2 when hummingbirds display an RQ=0.71 (fasted) and an RQ=1.0 (fed) is between 16 and 18%, depending on whether zero or perfect elastic energy storage is assumed. These values closely match theoretical expectations, indicating that a combination of mechanical power estimates and ;indirect calorimetry', i.e. the measurement of rates of gas exchange, enables precise estimates of ATP turnover and metabolic flux rates in vivo. The requirement for less oxygen when oxidizing carbohydrate suggests that carbohydrate oxidation may facilitate hovering flight in hummingbirds at high altitude.

  17. Effect of oxygenate additive on diesel engine fuel consumption and emissions operating with biodiesel-diesel blend at idling conditions

    Science.gov (United States)

    Mahmudul, H. M.; Hagos, F. Y.; Mamat, R.; Noor, M. M.; Yusri, I. M.

    2017-10-01

    Biodiesel is promising alternative fuel to run the automotive engine but idling is the main problem to run the vehicles in a big city. Vehicles running with idling condition cause higher fuel supply and higher emission level due to being having fuel residues in the exhaust. The purpose of this study is to evaluate the impact of alcohol additive on fuel consumption and emissions parameters under idling conditions when a multicylinder diesel engine operates with the diesel-biodiesel blend. The study found that using 5% butanol as an additive with B5 (5% Palm biodiesel + 95% diesel) blends fuel lowers brake specific fuel consumption and CO emissions by 38% and 20% respectively. But the addition of butanol increases NOx and CO2 emissions. Based on the result it can be said that 5% butanol can be used in a diesel engine with B5 without any engine modifications to tackle the idling problem.

  18. Accelerated oxygen consumption by catecholamines in the presence of aromatic nitro and nitroso compounds. Implications and neurotoxicity of nitro compounds

    International Nuclear Information System (INIS)

    Sridhar, K.

    1981-01-01

    The interactions of catecholamines with nitro and nitroso compounds are studied in view of the possible involvement of catecholamine type neurotransmitters in neurotoxicity caused by hypoxic cell sensitizers. The data reported suggest that neurotoxicity of nitro compounds may be due to depletion of oxygen, catecholamines and ascorbate in nerve tissue with concomitant generation of toxic species such as hydroxyl, hydronitroxyl and superoxide free radicals as well as nitroso and quinonoid derivatives. 5 references, 1 figure

  19. The kinetics of oxygen and SO2 consumption by red wines. What do they tell about oxidation mechanisms and about changes in wine composition?

    Science.gov (United States)

    Carrascón, Vanesa; Vallverdú-Queralt, Anna; Meudec, Emmanuelle; Sommerer, Nicolas; Fernandez-Zurbano, Purificación; Ferreira, Vicente

    2018-02-15

    This work seeks to understand the kinetics of O 2 and SO 2 consumption of air-saturated red wine as a function of its chemical composition, and to describe the chemical changes suffered during the process in relation to the kinetics. Oxygen Consumption Rates (OCRs) are faster with higher copper and epigallocatechin contents and with higher absorbance at 620nm and slower with higher levels of gallic acid and catechin terminal units in tannins. Acetaldehyde Reactive Polyphenols (ARPs) may be key elements determining OCRs. It is confirmed that SO 2 is poorly consumed in the first saturation. Phenylalanine, methionine and maybe, cysteine, seem to be consumed instead. A low SO 2 consumption is favoured by low levels of SO 2 , by a low availability of free SO 2 caused by a high anthocyanin/tannin ratio, and by a polyphenolic profile poor in epigallocatechin and rich in catechin-rich tannins. Wines consuming SO 2 efficiently consume more epigallocatechin, prodelphinidins and procyanidins. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Effects of respiratory alkalosis on human skeletal muscle metabolism at the onset of submaximal exercise.

    Science.gov (United States)

    LeBlanc, P J; Parolin, M L; Jones, N L; Heigenhauser, G J F

    2002-10-01

    The purpose of this study was to examine the effects of respiratory alkalosis on human skeletal muscle metabolism at rest and during submaximal exercise. Subjects exercised on two occasions for 15 min at 55 % of their maximal oxygen uptake while either hyperventilating (R-Alk) or breathing normally (Con). Muscle biopsies were taken at rest and after 1 and 15 min of exercise. At rest, no effects on muscle metabolism were observed in response to R-Alk. In the first minute of exercise, there was a delayed activation of pyruvate dehydrogenase (PDH) in R-Alk compared with Con, resulting in a reduced rate of pyruvate oxidation. Also, glycogenolysis was higher in R-Alk compared with Con, which was attributed to a higher availability of the monoprotonated form of inorganic phosphate (P(i)), resulting in an elevated rate of pyruvate production. The mismatch between pyruvate production and its oxidation resulted in net lactate accumulation. These effects were not seen after 15 min of exercise, with no further differences in muscle metabolism between conditions. The results from the present study suggest that respiratory alkalosis may play an important role in lactate accumulation during the transition from rest to exercise in acute hypoxic conditions, but that other factors mediate lactate accumulation during steady-state exercise.

  1. The relationship between body temperature, heart rate, breathing rate, and rate of oxygen consumption, in the tegu lizard (Tupinambis merianae) at various levels of activity.

    Science.gov (United States)

    Piercy, Joanna; Rogers, Kip; Reichert, Michelle; Andrade, Denis V; Abe, Augusto S; Tattersall, Glenn J; Milsom, William K

    2015-12-01

    The present study determined whether EEG and/or EMG recordings could be used to reliably define activity states in the Brazilian black and white tegu lizard (Tupinambis merianae) and then examined the interactive effects of temperature and activity states on strategies for matching O2 supply and demand. In a first series of experiments, the rate of oxygen consumption (VO2), breathing frequency (fR), heart rate (fH), and EEG and EMG (neck muscle) activity were measured in different sleep/wake states (sleeping, awake but quiet, alert, or moving). In general, metabolic and cardio-respiratory changes were better indictors of the transition from sleep to wake than were changes in the EEG and EMG. In a second series of experiments, the interactive effects of temperature (17, 27 and 37 °C) and activity states on fR, tidal volume (VT), the fraction of oxygen extracted from the lung per breath (FIO2-FEO2), fH, and the cardiac O2 pulse were quantified to determine the relative roles of each of these variables in accommodating changes in VO2. The increases in oxygen supply to meet temperature- and activity-induced increases in oxygen demand were produced almost exclusively by increases in fH and fR. Regression analysis showed that the effects of temperature and activity state on the relationships between fH, fR and VO2 was to extend a common relationship along a single curve, rather than separate relationships for each metabolic state. For these lizards, the predictive powers of fR and fH were maximized when the effects of changes in temperature, digestive state and activity were pooled. However, the best r(2) values obtained were 0.63 and 0.74 using fR and fH as predictors of metabolic rate, respectively.

  2. Spatiotemporal dynamics of phosphorus release, oxygen consumption and greenhouse gas emissions after localised soil amendment with organic fertilisers

    DEFF Research Database (Denmark)

    Christel, Wibke; Zhu, Kun; Hoefer, Christoph

    2016-01-01

    processes and fixation in the residue sphere, giving rise to distinct differences in nutrient availability, soil oxygen content and greenhouse gas (GHG) production. In this study we investigated the spatiotemporal dynamics of the reaction of manure solids and manure solids char with soil, focusing...... on their phosphorus (P) availability, as current emphasis on improving societal P efficiency through recycling waste or bio-based fertilisers necessitates a sound understanding of their behaviour. Soil layers amended at a constant P application rate with either pig manure solids or char made from pig manure solids...

  3. Feasibility of a 12-month-exercise intervention during and after radiation and chemotherapy in cancer patients: impact on quality of life, peak oxygen consumption, and body composition.

    Science.gov (United States)

    Grabenbauer, Alexander; Grabenbauer, Andrea J; Lengenfelder, Rosa; Grabenbauer, Gerhard G; Distel, Luitpold V

    2016-03-16

    Accumulating evidence suggests that exercise is effective in treating many of the acute and chronic side effects of anti-cancer therapy. A recent meta-analysis supported the use of exercise to prevent or treat fatigue and lymphoedema and to improve functional status in breast cancer patients. This trial was intended as a controlled, prospective feasibility study evaluating the impact of physical exercise (PE) in cancer patients during and after treatment with radio- and chemotherapy. Inclusion criteria were previous or ongoing treatment for cancer, motivation for PE of 0.5-1hour duration at least twice weekly for at least 3 months. Continuation of PE was encouraged thereafter. Every three months the following endpoints were assessed: Peak oxygen consumption as measured by supervised cardiopulmonary exercise test, body composition and quality of life. A total of 45 patients were included with a median age of 49 years. Forty were female and five male. Cancer types were: Breast cancer (n = 30/67 %), gastrointestinal cancer (n = 5/12 %), other types (n = 10/22 %). Thirty-eight (84 %) of the patients were included during curative treatment of their disease. Seven (16 %) were considered palliative. Adherence to the PE-programme longer than 6 months was noted for 41/45 (91 %) of the patients. Intensity of PE was thrice weekly in 32/45 (71 %), twice weekly in 11/45 (24 %). Two of 45 patients (5 %) had no PE. Mean peak oxygen consumption increased from 18.8 ± 5.6 ml/min/kg to 20.5 ± 3 ml/min/kg and 19.9 ± 4.7 ml/min/kg at 3 months (p = 0.005) and 12 months (p = 0.003), respectively. Median fat mass decreased from 30.7 ± 15 kg to 28.9 ± 15 kg and 29.5 ± 13 kg at 3 months (p = 0.001) and 12 months (p = 0.017), respectively. Global health status scores increased from a median baseline value of 54.9 ± 16.3 to 66.4 ± 14 % and 68.0 ± 20.3 % at 3 months (p = 0.001) and 12 months (p = 0.002), respectively. This exercise programme in cancer patients with 2-3 weekly

  4. A comparison of methods of predicting maximum oxygen uptake.

    OpenAIRE

    Grant, S; Corbett, K; Amjad, A M; Wilson, J; Aitchison, T

    1995-01-01

    The aim of this study was to compare the results from a Cooper walk run test, a multistage shuttle run test, and a submaximal cycle test with the direct measurement of maximum oxygen uptake on a treadmill. Three predictive tests of maximum oxygen uptake--linear extrapolation of heart rate of VO2 collected from a submaximal cycle ergometer test (predicted L/E), the Cooper 12 min walk, run test, and a multi-stage progressive shuttle run test (MST)--were performed by 22 young healthy males (mean...

  5. Relationship between iodine-123-beta-methyl-p-iodophenyl-pentadecanoic acid washout ratio and oxygen consumption in normal and ischemic myocardium

    International Nuclear Information System (INIS)

    Saito, Kimimasa; Okamoto, Ryuji; Saito, Yasuhiro

    1997-01-01

    The relationship between oxygen consumption and iodine-123-beta-methyl-p-iodophenyl-pentadecanoic acid ( 123 I-BMIPP) washout at rest and after exercise was investigated in normal and ischemic myocardium. Sixteen healthy volunteers and 14 patients with ischemic heart disease were examined. After injection of 111 MBq of 123 I-BMIPP, serial single photon emission computed tomography imaging was performed to evaluate washout ratio after 30 min and 1 hour of rest and after exercise. In the volunteers, the mean washout ratio was 3.3±3.5% after 1 hour of rest and increased during exercise. The exercise washout ratio showed a better correlation with net pressure rate product (net PRP: cumulative values of PRP during exercise) than with the peak PRP. The exercise washout ratio showed a strong correlation with the net PRP in the range from 180 to 300x10 3 mmHg·beat/min and a plateau of 10-15%. In the nine ischemic patients with net PRP≥300x10 3 mmHg·beat/min, the exercise washout ratio values were significantly elevated in normal segments relative to ischemic segments (10.1±1.9% vs 4.7±2.9%, p 3 mmHg·beat/min, washout ratio at rest and after exercise did not differ significantly between normal and ischemic segments. 123 I-BMIPP washout ratio increased with increased oxygen consumption during exercise in normal myocardium but not in ischemic myocardium. The patient must exercise before fatty acid metabolism can be compared between normal and ischemic myocardium. (author)

  6. Vastus lateralis surface and single motor unit EMG following submaximal shortening and lengthening contractions

    NARCIS (Netherlands)

    Altenburg, T.M.; de Ruiter, C.J.; Verdijk, P.W.L.; van Mechelen, W.; de Haan, A.

    2008-01-01

    A single shortening contraction reduces the force capacity of muscle fibers, whereas force capacity is enhanced following lengthening. However, how motor unit recruitment and discharge rate (muscle activation) are adapted to such changes in force capacity during submaximal contractions remains

  7. Submaximal physical strain and peak performance in handcycling versus handrim wheelchair propulsion

    NARCIS (Netherlands)

    Dallmeijer, A.J.; Zentgraaff, I.D.; Zijp, N.I.; van der Woude, L.H.V.

    2004-01-01

    Study design: Experimental study in subjects with paraplegia and nondisabled subjects. Objective: To compare submaximal physical strain and peak performance in handcycling and handrim wheelchair propulsion in wheelchair-dependent and nondisabled control subjects Setting: Amsterdam, The Netherlands.

  8. HIGD1A Regulates Oxygen Consumption, ROS Production, and AMPK Activity during Glucose Deprivation to Modulate Cell Survival and Tumor Growth

    Directory of Open Access Journals (Sweden)

    Kurosh Ameri

    2015-02-01

    Full Text Available Hypoxia-inducible gene domain family member 1A (HIGD1A is a survival factor induced by hypoxia-inducible factor 1 (HIF-1. HIF-1 regulates many responses to oxygen deprivation, but viable cells within hypoxic perinecrotic solid tumor regions frequently lack HIF-1α. HIGD1A is induced in these HIF-deficient extreme environments and interacts with the mitochondrial electron transport chain to repress oxygen consumption, enhance AMPK activity, and lower cellular ROS levels. Importantly, HIGD1A decreases tumor growth but promotes tumor cell survival in vivo. The human Higd1a gene is located on chromosome 3p22.1, where many tumor suppressor genes reside. Consistent with this, the Higd1a gene promoter is differentially methylated in human cancers, preventing its hypoxic induction. However, when hypoxic tumor cells are confronted with glucose deprivation, DNA methyltransferase activity is inhibited, enabling HIGD1A expression, metabolic adaptation, and possible dormancy induction. Our findings therefore reveal important new roles for this family of mitochondrial proteins in cancer biology.

  9. Spatiotemporal dynamics of phosphorus release, oxygen consumption and greenhouse gas emissions after localised soil amendment with organic fertilisers

    Energy Technology Data Exchange (ETDEWEB)

    Christel, Wibke [Department for Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C (Denmark); Department of Commerce, Industry and Agriculture, Danish Environmental Protection Agency, 1401 Copenhagen C (Denmark); Zhu, Kun [Department for Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C (Denmark); College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193 (China); Hoefer, Christoph [Rhizosphere Ecology and Biogeochemistry Group, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz-Strasse 24, 3430 Tulln (Austria); Kreuzeder, Andreas [Rhizosphere Ecology and Biogeochemistry Group, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz-Strasse 24, 3430 Tulln (Austria); Land Salzburg, Natur- und Umweltschutz, Gewerbe (Abteilung 5), Michael-Pacher-Straße 36, 5020 Salzburg (Austria); Santner, Jakob [Rhizosphere Ecology and Biogeochemistry Group, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz-Strasse 24, 3430 Tulln (Austria); Division of Agronomy, Department of Crop Sciences, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz-Strasse 24, 3430 Tulln (Austria); Bruun, Sander; Magid, Jakob [Department for Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C (Denmark); Jensen, Lars Stoumann, E-mail: lsj@plen.ku.dk [Department for Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C (Denmark)

    2016-06-01

    Organic fertilisation inevitably leads to heterogeneous distribution of organic matter and nutrients in soil, i.e. due to uneven surface spreading or inhomogeneous incorporation. The resulting localised hotspots of nutrient application will induce various biotic and abiotic nutrient turnover processes and fixation in the residuesphere, giving rise to distinct differences in nutrient availability, soil oxygen content and greenhouse gas (GHG) production. In this study we investigated the spatiotemporal dynamics of the reaction of manure solids and manure solids char with soil, focusing on their phosphorus (P) availability, as current emphasis on improving societal P efficiency through recycling waste or bio-based fertilisers necessitates a sound understanding of their behaviour. Soil layers amended at a constant P application rate with either pig manure solids or char made from pig manure solids were incubated for three weeks between layers of non-amended, P-depleted soil. Spatial and temporal changes in and around the amendment layers were simultaneously investigated in this study using a sandwich sensor consisting of a planar oxygen optode and multi-element diffusive gradients in thin films (DGT) gels, combined with GHG emission measurements. After three weeks of incubation, the soil containing a layer amended with manure solids had a lower overall O{sub 2} content and had emitted significantly more CO{sub 2} than the non-amended control or the char-amended soil. The P availability from manure solids was initially higher than that from the char, but decreased over time, whereas from the char-amended layer P availability increased in the same period. In both treatments, increases in P availability were confined to the amended soil layer and did not greatly affect P availability in the directly adjacent soil layers during the three-week incubation. These results highlight the importance of placing organic P fertilisers close to where the plant roots will grow in

  10. Spatiotemporal dynamics of phosphorus release, oxygen consumption and greenhouse gas emissions after localised soil amendment with organic fertilisers

    International Nuclear Information System (INIS)

    Christel, Wibke; Zhu, Kun; Hoefer, Christoph; Kreuzeder, Andreas; Santner, Jakob; Bruun, Sander; Magid, Jakob; Jensen, Lars Stoumann

    2016-01-01

    Organic fertilisation inevitably leads to heterogeneous distribution of organic matter and nutrients in soil, i.e. due to uneven surface spreading or inhomogeneous incorporation. The resulting localised hotspots of nutrient application will induce various biotic and abiotic nutrient turnover processes and fixation in the residuesphere, giving rise to distinct differences in nutrient availability, soil oxygen content and greenhouse gas (GHG) production. In this study we investigated the spatiotemporal dynamics of the reaction of manure solids and manure solids char with soil, focusing on their phosphorus (P) availability, as current emphasis on improving societal P efficiency through recycling waste or bio-based fertilisers necessitates a sound understanding of their behaviour. Soil layers amended at a constant P application rate with either pig manure solids or char made from pig manure solids were incubated for three weeks between layers of non-amended, P-depleted soil. Spatial and temporal changes in and around the amendment layers were simultaneously investigated in this study using a sandwich sensor consisting of a planar oxygen optode and multi-element diffusive gradients in thin films (DGT) gels, combined with GHG emission measurements. After three weeks of incubation, the soil containing a layer amended with manure solids had a lower overall O_2 content and had emitted significantly more CO_2 than the non-amended control or the char-amended soil. The P availability from manure solids was initially higher than that from the char, but decreased over time, whereas from the char-amended layer P availability increased in the same period. In both treatments, increases in P availability were confined to the amended soil layer and did not greatly affect P availability in the directly adjacent soil layers during the three-week incubation. These results highlight the importance of placing organic P fertilisers close to where the plant roots will grow in order to

  11. Effect of the dimetilsulfoxido in the response chemiluminescent and the consumption of oxygen of neutrophils activated human

    International Nuclear Information System (INIS)

    Garcia, J.

    2001-01-01

    Dimethylsulfoxide (DMSO), a hydroxyl radical scavenger, exerted a dose dependent inhibition on the luminol and lucigenin-enhanced chemiluminescent responses of human neutrophils activated with soluble and particulate stimulants. DMSO inhibition of the luminol chemiluminescense induced by calcium ionophore A23187 was probably due to OH scavenging, whereas inhibition of the lucigenin chemiluminescence suggested DMSO negatively affects the NADPH-dependent membrane oxidase of neutrophils. In agreement with this, DMSO moderately inhibited O2 consumption in PMN suspensions stimulated with chemotactic peptide and opsonized zymosan-induced luminol chemiluminescense was observed only when added before or in conjunction with stimulants, whereas A23187-induced chemiluminescense was inhibited by DMSO regardless of time of addition. Washing of DMSO-treated PMN resulted in increased luminol enhanced chemiluminescense in response to chemotactic peptide and opsonized zymosan. This is consistent with the idea that DMSO may be interfering with activation of the membrane subunits of the oxidase by translocation and docking of the cytoplasmic, regulatory subunits. These data imply that DMSO inhibits neutrophil chemiluminescense both by OH scavenging and interfering with oxidase activation. Key words:Dimethylsulfoxide, chemiluminescent, luminol, lucigenin,neutrophils [es

  12. Effects of music tempo upon submaximal cycling performance.

    Science.gov (United States)

    Waterhouse, J; Hudson, P; Edwards, B

    2010-08-01

    In an in vivo laboratory controlled study, 12 healthy male students cycled at self-chosen work-rates while listening to a program of six popular music tracks of different tempi. The program lasted about 25 min and was performed on three occasions--unknown to the participants, its tempo was normal, increased by 10% or decreased by 10%. Work done, distance covered and cadence were measured at the end of each track, as were heart rate and subjective measures of exertion, thermal comfort and how much the music was liked. Speeding up the music program increased distance covered/unit time, power and pedal cadence by 2.1%, 3.5% and 0.7%, respectively; slowing the program produced falls of 3.8%, 9.8% and 5.9%. Average heart rate changes were +0.1% (faster program) and -2.2% (slower program). Perceived exertion and how much the music was liked increased (faster program) by 2.4% and 1.3%, respectively, and decreased (slower program) by 3.6% and 35.4%. That is, healthy individuals performing submaximal exercise not only worked harder with faster music but also chose to do so and enjoyed the music more when it was played at a faster tempo. Implications of these findings for improving training regimens are discussed.

  13. Triphasic behavioral response of motor units to submaximal fatiguing exercise.

    Science.gov (United States)

    Dorfman, L J; Howard, J E; McGill, K C

    1990-07-01

    We have measured the firing rate and amplitude of 4551 motor unit action potentials (MUAPs) recorded with concentric needle electrodes from the brachial biceps muscles of 10 healthy young adults before, during, and after 45 minutes of intermittent isometric exercise at 20% of maximum voluntary contraction (MVC), using an automatic method for decomposition of electromyographic activity (ADEMG). During and after exercise, MUAPs derived from contractions of 30% MVC showed progressive increase in mean firing rate (P less than or equal to .01) and amplitude (P less than or equal to .05). The firing rate increase preceded the rise in mean amplitude, and was evident prior to the development of fatigue, defined as reduction of MVC. Analysis of individual potentials revealed that the increase in firing rate and in amplitude reflected different MUAP subpopulations. A short-term (less than 1 minute) reduction in MUAP firing rates (P less than or equal to .05) was also observed at the onset of each test contraction. These findings suggest that motor units exhibit a triphasic behavioral response to prolonged submaximal exercise: (1) short-term decline and stabilization of onset firing rates, followed by (2) gradual and progressive increase in firing rates and firing variability, and then by (3) recruitment of additional (larger) motor units. The (2) and (3) components presumably compensate for loss of force-generating capacity in the exercising muscle, and give rise jointly to the well-known increase in total surface EMG which accompanies muscle fatigue.

  14. Neuromuscular function of the quadriceps muscle during isometric maximal, submaximal and submaximal fatiguing voluntary contractions in knee osteoarthrosis patients.

    Directory of Open Access Journals (Sweden)

    Anett Mau-Moeller

    and neuromuscular activation, but also with an impaired position and torque control at submaximal torque levels, an altered EMG-torque relationship and a higher performance fatigability of the quadriceps muscle. It is recommended that the rehabilitation includes strengthening and fatiguing exercises at maximal and submaximal force levels.

  15. Feasibility of a 12-month-exercise intervention during and after radiation and chemotherapy in cancer patients: impact on quality of life, peak oxygen consumption, and body composition

    International Nuclear Information System (INIS)

    Grabenbauer, Alexander; Grabenbauer, Andrea J.; Lengenfelder, Rosa; Grabenbauer, Gerhard G.; Distel, Luitpold V.

    2016-01-01

    Accumulating evidence suggests that exercise is effective in treating many of the acute and chronic side effects of anti-cancer therapy. A recent meta-analysis supported the use of exercise to prevent or treat fatigue and lymphoedema and to improve functional status in breast cancer patients. This trial was intended as a controlled, prospective feasibility study evaluating the impact of physical exercise (PE) in cancer patients during and after treatment with radio- and chemotherapy. Inclusion criteria were previous or ongoing treatment for cancer, motivation for PE of 0.5-1hour duration at least twice weekly for at least 3 months. Continuation of PE was encouraged thereafter. Every three months the following endpoints were assessed: Peak oxygen consumption as measured by supervised cardiopulmonary exercise test, body composition and quality of life. A total of 45 patients were included with a median age of 49 years. Forty were female and five male. Cancer types were: Breast cancer (n = 30/67 %), gastrointestinal cancer (n = 5/12 %), other types (n = 10/22 %). Thirty-eight (84 %) of the patients were included during curative treatment of their disease. Seven (16 %) were considered palliative. Adherence to the PE-programme longer than 6 months was noted for 41/45 (91 %) of the patients. Intensity of PE was thrice weekly in 32/45 (71 %), twice weekly in 11/45 (24 %). Two of 45 patients (5 %) had no PE. Mean peak oxygen consumption increased from 18.8 ± 5.6 ml/min/kg to 20.5 ± 3 ml/min/kg and 19.9 ± 4.7 ml/min/kg at 3 months (p = 0.005) and 12 months (p = 0.003), respectively. Median fat mass decreased from 30.7 ± 15 kg to 28.9 ± 15 kg and 29.5 ± 13 kg at 3 months (p = 0.001) and 12 months (p = 0.017), respectively. Global health status scores increased from a median baseline value of 54.9 ± 16.3 to 66.4 ± 14 % and 68.0 ± 20.3 % at 3 months (p = 0.001) and 12 months (p = 0.002), respectively. This exercise programme in cancer patients with 2–3 weekly

  16. Aerobic fitness and metabolic health in children: A clinical validation of directly measured maximal oxygen consumption versus performance measures as markers of health.

    Science.gov (United States)

    Aadland, Eivind; Kvalheim, Olav Martin; Rajalahti, Tarja; Skrede, Turid; Resaland, Geir Kåre

    2017-09-01

    High aerobic fitness is consistently associated with a favorable metabolic health profile in children. However, measurement of oxygen uptake, regarded as the gold standard for evaluating aerobic fitness, is often not feasible. Thus, the aim of the present study was to perform a clinical validation of three measures of aerobic fitness (peak oxygen consumption [VO 2peak ] and time to exhaustion [TTE] determined from a graded treadmill protocol to exhaustion, and the Andersen intermittent running test) with clustered metabolic health in 10-year-old children. We included 93 children (55 boys and 38 girls) from Norway during 2012-2013 in the study. Associations between aerobic fitness and three different composite metabolic health scores (including lipoprotein subgroup particle concentrations, triglyceride, glucose, systolic blood pressure, and waist-to-height ratio) were determined by regression analyses adjusting for sex. The relationships among the measures of aerobic fitness were r  = 0.78 for VO 2peak vs. TTE, r  = 0.63 for VO 2peak vs. the Andersen test, and r  = 0.67 for TTE vs. the Andersen test. The Andersen test showed the strongest associations across all markers of metabolic health ( r  = - 0.45 to - 0.31, p  fitness do not stand back as markers of metabolic health status in children, compared to VO 2peak . This is of great importance as good field tests provide opportunities for measuring aerobic fitness in many settings where measuring VO 2peak are impossible.

  17. Electrostimulation improves muscle perfusion but does not affect either muscle deoxygenation or pulmonary oxygen consumption kinetics during a heavy constant-load exercise.

    Science.gov (United States)

    Layec, Gwenael; Millet, Grégoire P; Jougla, Aurélie; Micallef, Jean-Paul; Bendahan, David

    2008-02-01

    Electromyostimulation (EMS) is commonly used as part of training programs. However, the exact effects at the muscle level are largely unknown and it has been recently hypothesized that the beneficial effect of EMS could be mediated by an improved muscle perfusion. In the present study, we investigated rates of changes in pulmonary oxygen consumption (VO(2p)) and muscle deoxygenation during a standardized exercise performed after an EMS warm-up session. We aimed at determining whether EMS could modify pulmonary O(2) uptake and muscle deoxygenation as a result of improved oxygen delivery. Nine subjects performed a 6-min heavy constant load cycling exercise bout preceded either by an EMS session (EMS) or under control conditions (CONT). VO(2p) and heart rate (HR) were measured while deoxy-(HHb), oxy-(HbO(2)) and total haemoglobin/myoglobin (Hb(tot)) relative contents were measured using near infrared spectroscopy. EMS significantly increased (P < 0.05) the Hb(tot) resting level illustrating a residual hyperaemia. The EMS priming exercise did not affect either the HHb time constant (17.7 +/- 14.2 s vs. 13.1 +/- 2.3 s under control conditions) or the VO(2p) kinetics (time-constant = 18.2 +/- 5.2 s vs. 15.4 +/- 4.6 s under control conditions). Likewise, the other VO(2p) parameters were unchanged. Our results further indicated that EMS warm-up improved muscle perfusion through a residual hyperaemia. However, neither VO(2p) nor [HHb] kinetics were modified accordingly. These results suggest that improved O(2) delivery by residual hyperaemia induced by EMS does not accelerate the rate of aerobic metabolism during heavy exercise at least in trained subjects.

  18. Assessment of cardiorespiratory fitness using submaximal protocol in older adults with mood disorder and Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Natacha Alves de Oliveira

    2013-01-01

    Full Text Available BACKGROUND: Evidence has shown benefits for mental health through aerobic training oriented in percentage of VO2max, indicating the importance of this variable for clinical practice. OBJECTIVE: To validate a method for estimating VO2max using a submaximal protocol in elderly patients with clinically diagnosis as major depressive disorder (MDD and Parkinson's disease (PD. METHODS: The sample comprised 18 patients (64.22 ± 9.92 years with MDD (n = 7 and with PD (n = 11. Three evaluations were performed: I disease staging, II direct measurement of VO2max and III submaximal exercise test. Linear regression was performed to verify the accuracy of estimation in VO2max established in ergospirometry and the predicted VO2max from the submaximal test measurement. We also analyzed the correlation between the Bland-Altman procedures. RESULTS: The regression analysis showed that VO2max values estimated by submaximal protocol associated with the VO2max measured, both in absolute values (R² = 0.65; SEE = 0.26; p < 0.001 and the relative (R² = 0.56; SEE = 3.70; p < 0.001. The Bland-Altman plots for analysis of agreement of showed a good correlation between the two measures. DISCUSSION: The VO2max predicted by submaximal protocol demonstrated satisfactory criterion validity and simple execution compared to ergospirometry.

  19. Delayed Effects of Remote Limb Ischemic Preconditioning on Maximum Oxygen Consumption, Lactate Release and Pulmonary Function Tests in Athletes and non-Athletes

    Directory of Open Access Journals (Sweden)

    Mahnaz Momeni

    2016-11-01

    Full Text Available Background: Remote Ischemic Preconditioning (RIPC improves exercise performance, and since this phenomenon has two phases, the aim of the current study was to investigate the delayed effects of remote ischemic preconditioning on cardiopulmonary function in athletes and non-athletes. Materials and Methods: 25 male and female students were studied in two main athletes and non-athletes groups. RIPC was induced by using 3 cycles of alternative 5 minutes ischemia and 5 minutes reperfusion at arms of participants. Cardiopulmonary tests were measured before, after and 24 hours after inducing remote ischemic preconditioning. Maximum oxygen consumption (VO2max estimated by using queen steps test. Results: Analysis of data demonstrated that delayed RIPC in non-athletes group caused significant improvement in Forced Expiratory Volume in one second (FEV1 and Maximum Voluntary Ventilation (MVV and noticeable improvement in some other parameters of pulmonary function tests. Moreover, it decreased systolic blood pressure and heart rate and decreased lactate release in both groups especially athletes group but it had no significant effect on VO2max of both groups. Conclusion: Delayed RIPC improves cardiovascular function of athletes and pulmonary function of non-athletes subjects. Thus, it can be considered as a good replacement for doping to improve sports performance of subjects in sports tournaments.

  20. Study of the influence of fuel load and slope on a fire spreading across a bed of pine needles by using oxygen consumption calorimetry

    Science.gov (United States)

    Tihay, V.; Morandini, F.; Santoni, P. A.; Perez-Ramirez, Y.; Barboni, T.

    2012-11-01

    A set of experiments using a Large Scale Heat Release Rate Calorimeter was conducted to test the effects of slope and fuel load on the fire dynamics. Different parameters such as the geometry of the flame front, the rate of spread, the mass loss rate and the heat release rate were investigated. Increasing the fuel load or the slope modifies the fire behaviour. As expected, the flame length and the rate of spread increase when fuel load or slope increases. The heat release rate does not reach a quasi-steady state when the propagation takes place with a slope of 20° and a high fuel load. This is due to an increase of the length of the fire front leading to an increase of fuel consumed. These considerations have shown that the heat release can be estimated with the mass loss rate by considering the effective heat of combustion. This approach can be a good alternative to estimate accurately the fireline intensity when the measure of oxygen consumption is not possible.

  1. Study of the influence of fuel load and slope on a fire spreading across a bed of pine needles by using oxygen consumption calorimetry

    International Nuclear Information System (INIS)

    Tihay, V; Morandini, F; Santoni, P A; Perez-Ramirez, Y; Barboni, T

    2012-01-01

    A set of experiments using a Large Scale Heat Release Rate Calorimeter was conducted to test the effects of slope and fuel load on the fire dynamics. Different parameters such as the geometry of the flame front, the rate of spread, the mass loss rate and the heat release rate were investigated. Increasing the fuel load or the slope modifies the fire behaviour. As expected, the flame length and the rate of spread increase when fuel load or slope increases. The heat release rate does not reach a quasi-steady state when the propagation takes place with a slope of 20° and a high fuel load. This is due to an increase of the length of the fire front leading to an increase of fuel consumed. These considerations have shown that the heat release can be estimated with the mass loss rate by considering the effective heat of combustion. This approach can be a good alternative to estimate accurately the fireline intensity when the measure of oxygen consumption is not possible.

  2. Contribution of proton leak to oxygen consumption in skeletal muscle during intense exercise is very low despite large contribution at rest.

    Directory of Open Access Journals (Sweden)

    Bernard Korzeniewski

    Full Text Available A computer model was used to simulate the dependence of protonmotive force (Δp, proton leak and phenomenological (involving proton leak ATP/O2 ratio on work intensity in skeletal muscle. Δp, NADH and proton leak decreased with work intensity. The contribution of proton leak to oxygen consumption ([Formula: see text] decreased from about 60% at rest to about 3 and 1% at moderate and heavy/severe exercise, respectively, while the ATP/O2 ratio increased from 2.1 to 5.5 and 5.7. A two-fold increase in proton leak activity or its decrease to zero decreased/increased the ATP/O2 ratio by only about 3 and 1% during moderate and heavy/severe exercise, respectively. The low contribution of proton leak to [Formula: see text] in intensively working skeletal muscle was mostly caused by a huge increase in ATP usage intensity during rest-to-work transition, while OXPHOS, and thus oxidative ATP supply and [Formula: see text] related to it, was mostly stimulated by high each-step activation (ESA of OXPHOS complexes. The contribution of proton leak to [Formula: see text] and ATP/O2 ratio in isolated mitochondria should not be directly extrapolated to working muscle, as mitochondria lack ESA, at least in the absence of Ca2+, and therefore [Formula: see text] cannot be elevated as much as in intact muscle.

  3. Effects of x-irradiation on cell division, oxygen consumption, and growth medium pH of an insect cell line cultured in vitro

    International Nuclear Information System (INIS)

    Koval, T.M.; Myser, W.C.; Hink, W.F.

    1975-01-01

    Cultured Trichoplusia ni cells in exponential growth were administered x-ray doses of 10,000 R and then subcultured. The untreated cell population began exponential growth within a few hours after subculture, eventually reaching stationary growth phase 96 hr later at a cell density of 2.08 x 10 6 cells/ml, whereas the irradiated cell population did not change for 24 hr after irradiation and then began exponential growth at a rate similar to that of control cells, also reaching stationary phase at 96 hr, but at a cell density of 0.93 x 10 6 cells/ml, which is less than half the maximum density of controls. From 24 to 96 hr after treatment, the x-irradiated cells were characterized by an increased consumption of oxygen that was nearly twice the amount utilized by control cells. The pH of the cell growth medium increases over 96 hr from 6.3 to 6.6 for irradiated as well as for untreated cultures, but since the number of x-rayed cells is less than half the number of untreated cells, the pH increase, per cell, of medium from irradiated cultures is about twice that of medium from control cultures

  4. The contribution of gastric digestion and ingestion of amino acids on the postprandial rise in oxygen consumption, heart rate and growth of visceral organs in pythons.

    Science.gov (United States)

    Enok, Sanne; Simonsen, Lasse Stærdal; Wang, Tobias

    2013-05-01

    To investigate the contribution of gastric and intestinal processes to the postprandial rise in metabolism in pythons (Python regius), we measured oxygen consumption after ligation of the pyloric sphincter to prevent the chyme from entering the intestine. Pyloric blockade reduced the postprandial rise in metabolism during the first 18h after ingestion of mice amounting to 18% of the snake's body mass by 60%. In another series of the experiments, we showed that infusion of amino acids directly into the stomach or the intestine elicited similar metabolic responses. This indicates a lower gastric contribution to the SDA response than previously reported. To include an assessment of the gastric contribution to the postprandial cardiovascular response, we also measured blood and heart rate. While heart rate increased during digestion in snakes with pyloric blockade, there was no rise in the double-blocked heart rates compared to fasting controls. Thus, the non-adrenergic-non-cholinergic factor that stimulates heart rate during digestion does not stem from the stomach. Finally, there was no growth of the visceral organs in response to digestion when chyme was prevented from reaching the intestine. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Effect of salinity changes on the bacterial diversity, photosynthesis and oxygen consumption of cyanobacterial mats from an intertidal flat of the Arabian Gulf.

    Science.gov (United States)

    Abed, Raeid M M; Kohls, Katharina; de Beer, Dirk

    2007-06-01

    The effects of salinity fluctuation on bacterial diversity, rates of gross photosynthesis (GP) and oxygen consumption in the light (OCL) and in the dark (OCD) were investigated in three submerged cyanobacterial mats from a transect on an intertidal flat. The transect ran 1 km inland from the low water mark along an increasingly extreme habitat with respect to salinity. The response of GP, OCL and OCD in each sample to various salinities (65 per thousand, 100 per thousand, 150 per thousand and 200 per thousand) were compared. The obtained sequences and the number of unique operational taxonomic units showed clear differences in the mats' bacterial composition. While cyanobacteria decreased from the lower to the upper tidal mat, other bacterial groups such as Chloroflexus and Cytophaga/Flavobacteria/Bacteriodetes showed an opposite pattern with the highest dominance in the middle and upper tidal mats respectively. Gross photosynthesis and OCL at the ambient salinities of the mats decreased from the lower to the upper tidal zone. All mats, regardless of their tidal location, exhibited a decrease in areal GP, OCL and OCD rates at salinities > 100 per thousand. The extent of inhibition of these processes at higher salinities suggests an increase in salt adaptation of the mats microorganisms with distance from the low water line. We conclude that the resilience of microbial mats towards different salinity regimes on intertidal flats is accompanied by adjustment of the diversity and function of their microbial communities.

  6. Retinoic acid-induced differentiation increases the rate of oxygen consumption and enhances the spare respiratory capacity of mitochondria in SH-SY5Y cells.

    Science.gov (United States)

    Xun, Zhiyin; Lee, Do-Yup; Lim, James; Canaria, Christie A; Barnebey, Adam; Yanonne, Steven M; McMurray, Cynthia T

    2012-04-01

    Retinoic acid (RA) is used in differentiation therapy to treat a variety of cancers including neuroblastoma. The contributing factors for its therapeutic efficacy are poorly understood. However, mitochondria (MT) have been implicated as key effectors in RA-mediated differentiation process. Here we utilize the SH-SY5Y human neuroblastoma cell line as a model to examine how RA influences MT during the differentiation process. We find that RA confers an approximately sixfold increase in the oxygen consumption rate while the rate of glycolysis modestly increases. RA treatment does not increase the number of MT or cause measurable changes in the composition of the electron transport chain. Rather, RA treatment significantly increases the mitochondrial spare respiratory capacity. We propose a competition model for the therapeutic effects of RA. Specifically, the high metabolic rate in differentiated cells limits the availability of metabolic nutrients for use by the undifferentiated cells and suppresses their growth. Thus, RA treatment provides a selective advantage for the differentiated state. Published by Elsevier Ireland Ltd.

  7. Systemic inflammatory responses to maximal versus submaximal lengthening contractions of the elbow flexors.

    Science.gov (United States)

    Peake, Jonathan M; Nosaka, Kazunori; Muthalib, Makii; Suzuki, Katsuhiko

    2006-01-01

    We compared changes in markers of muscle damage and systemic inflammation after submaximal and maximal lengthening muscle contractions of the elbow flexors. Using a cross-over design, 10 healthy young men not involved in resistance training completed a submaximal trial (10 sets of 60 lengthening contractions at 10% maximum isometric strength, 1 min rest between sets), followed by a maximal trial (10 sets of three lengthening contractions at 100% maximum isometric strength, 3 min rest between sets). Lengthening contractions were performed on an isokinetic dynamometer. Opposite arms were used for the submaximal and maximal trials, and the trials were separated by a minimum of two weeks. Blood was sampled before, immediately after, 1 h, 3 h, and 1-4 d after each trial. Total leukocyte and neutrophil numbers, and the serum concentration of soluble tumor necrosis factor-alpha receptor 1 were elevated after both trials (P < 0.01), but there were no differences between the trials. Serum IL-6 concentration was elevated 3 h after the submaximal contractions (P < 0.01). The concentrations of serum tumor necrosis factor-alpha, IL-1 receptor antagonist, IL-10, granulocyte-colony stimulating factor and plasma C-reactive protein remained unchanged following both trials. Maximum isometric strength and range of motion decreased significantly (P < 0.001) after both trials, and were lower from 1-4 days after the maximal contractions compared to the submaximal contractions. Plasma myoglobin concentration and creatine kinase activity, muscle soreness and upper arm circumference all increased after both trials (P < 0.01), but were not significantly different between the trials. Therefore, there were no differences in markers of systemic inflammation, despite evidence of greater muscle damage following maximal versus submaximal lengthening contractions of the elbow flexors.

  8. The effect of short-term dimethylglycine treatment on oxygen consumption in cytochrome oxidase deficiency: a double-blind randomized crossover clinical trial.

    Science.gov (United States)

    Liet, Jean-Michel; Pelletier, Véronique; Robinson, Brian H; Laryea, Maurice D; Wendel, Udo; Morneau, Sylvain; Morin, Charles; Mitchell, Grant; Lacroix, Jacques

    2003-01-01

    To study the effectiveness of dimethylglycine (DMG) on oxygen consumption (VO(2)) in children with Saguenay-Lac-Saint-Jean cytochrome-c oxidase (SLSJ-COX) deficiency (OMIM 220111). In a crossover randomized double-blind clinical trial, 5 children with SLSJ-COX deficiency, who were stable and old enough to comply with VO(2) measurement, were treated with placebo or DMG for 3 days, and with the alternate treatment after a 2-week washout period. VO(2) was measured by indirect calorimetry before and after treatment. Dietary caloric intake was calculated for 3 days before each measurement. Mean caloric intakes per day were 1562 and 1342 kcal x m(-2) before and during placebo, 1,336 and 1,380 before and during DMG, respectively. DMG was well tolerated and, in all cases, resulted in markedly increased blood DMG levels (617 + 203 mmol x L(-1)), versus 0 to 2 mmol x L(-1) without treatment. Mean VO(2) was lower after administration of either DMG (-1 +/- 3 mL x min(-1) x m(-2)) or placebo (-6 +/- 4), but neither difference was statistically significant. There was no detectable effect of DMG treatment on blood levels of lactate, pyruvate, bicarbonate, or pH. VO(2) values of patients (range, 101-135 mL x min(-1) x m(-2)) were lower than published norms (150-160 mL x min(-1) x m(-2)). This study suggests that treatment with DMG does not substantially change VO(2) in children with SLSJ-COX deficiency.

  9. The influence of ascorbic acid on the oxygen consumption and the heat production by the cells of wheat seedling roots with their mitochondrial electron transport chain inhibited at complexes I and III

    International Nuclear Information System (INIS)

    Gordon, L.K.; Rakhmatullina, D.F.; Ogorodnikova, T.I.; Alyabyev, A.J.; Minibayeva, F.V.; Loseva, N.L.; Mityashina, S.Y.

    2007-01-01

    The influence of exogenous ascorbic acid (AsA) on oxidative phosphorylation was studied using wheat seedling roots. Treatment of them with AsA stimulated the rates of oxygen consumption and the heat production and caused a decrease of the respiratory coefficient. The increase in respiration was prevented by inhibitors of ascorbate oxidase, diethyldithiocarbamate (DEDTC), and of cytochrome oxidase, cyanide (KCN). Exogenous AsA sharply stimulated the rate of oxygen consumption of roots when complexes I and III of the mitochondrial electron transport chain were inhibited by rotenone and antimycin A, respectively, while the rates of heat production did not change significantly. It is concluded that AsA is a potent energy substrate, which can be used in conditions of failing I and III complexes in the mitochondrial electron transport chain

  10. THE EFFECT OF SUBMAXIMAL INHALATION ON MEASURES DERIVED FROM FORCED EXPIRATORY SPIROMETRY

    Science.gov (United States)

    THE EFFECT OF SUBMAXIMAL INHALATION ON MEASURES DERIVED FROM FORCED EXPIRATORY SPIROMETRY. William F. McDonnell Human Studies Division, NHEERL, U.S. Environmental Protection Agency, RTP, NC 27711. Short-term exposure to ozone results in a neurally-mediated decrease in the ab...

  11. Systolic blood pressure reactivity during submaximal exercise and acute psychological stress in youth

    Science.gov (United States)

    Background: Studies in youth show an association between systolic blood-pressure (SBP) reactivity to acute psychological stress and carotid artery intima-media thickness (CIMT). However, it has not yet been determined whether SBP reactivity during submaximal exercise is also associated with CIMT i...

  12. Effects of Training on the Estimation of Muscular Moment in Submaximal Exercise

    Science.gov (United States)

    Leverrier, Celine; Gauthier, Antoine; Nicolas, Arnaud; Molinaro, Corinne

    2011-01-01

    The purpose of this study was to observe the effects of a submaximal isometric training program on estimation capacity at 25, 50, and 75% of maximal contraction in isometric action and at two angular velocities. The second purpose was to study the variability of isometric action. To achieve these purposes, participants carried out an isokinetic…

  13. Effects of Wheel and Hand-Rim Size on Submaximal Propulsion in Wheelchair Athletes

    NARCIS (Netherlands)

    Mason, Barry S.; Van der Woude, Lucas H. V.; Tolfrey, Keith; Lenton, John P.; Goosey-Tolfrey, Victoria L.

    MASON, B. S., L. H. V. VAN DER WOUDE, K. TOLFREY, J. P. LENTON, and V. L. GOOSEY-TOLFREY. Effects of Wheel and Hand-Rim Size on Submaximal Propulsion in Wheelchair Athletes. Med. Sci. Sports Exerc., Vol. 44, No. 1, pp. 126-134, 2012. Purpose: This study aimed to investigate the effects of fixed gear

  14. Is an elevated submaximal heart rate associated with psychomotor slowness in young elite soccer players?

    NARCIS (Netherlands)

    Brink, Michel S.; Visscher, Chris; Schmikli, Sandor L.; Nederhof, E.; Lemmink, Koen A. P. M.

    2013-01-01

    The aim of the present study was to find early markers for overreaching that are applicable in sport practice. In a group of elite soccer players aged 1518, the stressrecovery balance and reaction times before and after exercise were assessed. Overreaching was indicated by an elevated submaximal

  15. A Short Submaximal test to determine the fatigue threshold of knee extensors in young men

    NARCIS (Netherlands)

    de Ruiter, C.J.; Hamacher, P.; Wolfs, B.G.A.

    Purpose Recently, a fatigue threshold obtained during submaximal repetitive isometric knee extensor contractions was related to VO 2max measured during cycling and to exercise endurance. However, test duration is quite long (20-30 min in young people) to be of practical and possibly clinical use.

  16. Variation in heart rate during submaximal exercise: Implications for monitoring training : Implications for monitoring training

    NARCIS (Netherlands)

    Lamberts, R.P.; Lemmink, K.A.P.M.; Durandt, J.J.; Lambert, M.I.

    2004-01-01

    A change in heart rate at a controlled submaximal exercise intensity is used as a marker of training status. However, the standard error of measurement has not been studied systematically, and therefore a change in heart rate, which can be considered relevant, has not been determined. Forty-four

  17. Critical windows in embryonic development: Shifting incubation temperatures alter heart rate and oxygen consumption of Lake Whitefish (Coregonus clupeaformis) embryos and hatchlings.

    Science.gov (United States)

    Eme, J; Mueller, C A; Manzon, R G; Somers, C M; Boreham, D R; Wilson, J Y

    2015-01-01

    Critical windows are periods of developmental susceptibility when the phenotype of an embryonic, juvenile or adult animal may be vulnerable to environmental fluctuations. Temperature has pervasive effects on poikilotherm physiology, and embryos are especially vulnerable to temperature shifts. To identify critical windows, we incubated whitefish embryos at control temperatures of 2°C, 5°C, or 8°C, and shifted treatments among temperatures at the end of gastrulation or organogenesis. Heart rate (fH) and oxygen consumption ( [Formula: see text] ) were measured across embryonic development, and [Formula: see text] was measured in 1-day old hatchlings. Thermal shifts, up or down, from initial incubation temperatures caused persistent changes in fH and [Formula: see text] compared to control embryos measured at the same temperature (2°C, 5°C, or 8°C). Most prominently, when embryos were measured at organogenesis, shifting incubation temperature after gastrulation significantly lowered [Formula: see text] or fH. Incubation at 2°C or 5°C through gastrulation significantly lowered [Formula: see text] (42% decrease) and fH (20% decrease) at 8°C, incubation at 2°C significantly lowered [Formula: see text] (40% decrease) and fH (30% decrease) at 5°C, and incubation at 5°C and 8°C significantly lowered [Formula: see text] at 2°C (27% decrease). Through the latter half of development, [Formula: see text] and fH in embryos were not different from control values for thermally shifted treatments. However, in hatchlings measured at 2°C, [Formula: see text] was higher in groups incubated at 5°C or 8°C through organogenesis, compared to 2°C controls (43 or 65% increase, respectively). Collectively, these data suggest that embryonic development through organogenesis represents a critical window of embryonic and hatchling phenotypic plasticity. This study presents an experimental design that identified thermally sensitive periods for fish embryos. Crown Copyright

  18. Fat oxidation, hormonal and plasma metabolite kinetics during a submaximal incremental test in lean and obese adults.

    Science.gov (United States)

    Lanzi, Stefano; Codecasa, Franco; Cornacchia, Mauro; Maestrini, Sabrina; Salvadori, Alberto; Brunani, Amelia; Malatesta, Davide

    2014-01-01

    This study aimed to compare fat oxidation, hormonal and plasma metabolite kinetics during exercise in lean (L) and obese (O) men. Sixteen L and 16 O men [Body Mass Index (BMI): 22.9 ± 0.3 and 39.0 ± 1.4 kg · m(-2)] performed a submaximal incremental test (Incr) on a cycle-ergometer. Fat oxidation rates (FORs) were determined using indirect calorimetry. A sinusoidal model, including 3 independent variables (dilatation, symmetry, translation), was used to describe fat oxidation kinetics and determine the intensity (Fat(max)) eliciting maximal fat oxidation. Blood samples were drawn for the hormonal and plasma metabolite determination at each step of Incr. FORs (mg · FFM(-1) · min(-1)) were significantly higher from 20 to 30% of peak oxygen uptake (VO2peak) in O than in L and from 65 to 85% VO2peak in L than in O (p ≤ 0.05). FORs were similar in O and in L from 35 to 60% VO2peak. Fat max was 17% significantly lower in O than in L (poxidation kinetics were characterized by similar translation, significantly lower dilatation and left-shift symmetry in O compared with L (poxidation at high exercise intensities suggest that the difference in the fat oxidation kinetics is likely linked to impaired muscular capacity to oxidize NEFA in O. These results may have important implications for the appropriate exercise intensity prescription in training programs designed to optimize fat oxidation in O.

  19. Lactate Accumulation in Muscle and Blood during Submaximal Exercise

    Science.gov (United States)

    1981-09-21

    exercise, fast and slow twitch fibers Short title: Lactate in muscle and blood P.A. Tesch, W.L. Daniels and D.S. Sharp Exercise Physiology Division, U.S...KIRBY, R.L. & BELCASTRO, A.N. 1978. Relationship between slow - twitch muscle fibres and lactic acid removal. Can J Appl Sports Sci 3:160-162. BRODAL, P...oxygen uptake (Karlsson 1971, Knuttgen & Saltin 1972). It is generally agreed that the main muscle fiber type to be recruited below this level is the slow

  20. The effect of adrenaline and high Ca2+ on the mechanical performance and oxygen consumption of the isolated perfused trout (Oncorhynchus mykiss) heart

    DEFF Research Database (Denmark)

    Rytter, Dorte; Gesser, Hans

    2007-01-01

    In heart muscle from mammals, catecholamines frequently evoke an oxygen waste and reduce efficiency. It was examined if this also applies to fish in which heart muscle activity is often restricted by oxygen availability. In the isolated perfused heart from rainbow trout, adrenaline (0.5 micro...

  1. Post-ischaemic changes in the response time of oxygen consumption to demand in the isolated rat heart are mediated partly by calcium and glycolysis

    NARCIS (Netherlands)

    Zuurbier, C. J.; Ince, C.

    2002-01-01

    This study examined whether different durations of ischaemia (I) and reperfusion (R) altered the kinetics of O-2 consumption-to-demand matching and the contribution of changes in calcium and metabolic pathways to possible alterations. The response time of mitochondrial O-2 consumption (t(mito)) to a

  2. Water flow requirements related to oxygen consumption in juveniles of Oplegnathus insignis Requerimientos de flujo de agua en función del consumo de oxígeno en juveniles de Oplegnathus insignis

    Directory of Open Access Journals (Sweden)

    Elio Segovia

    2012-09-01

    Full Text Available In this study the oxygen consumption rate in four groups of Oplegnathus insignis was examined under three different water temperatures 13, 18 and 23°C. Average weight of each group of fish was 9.5, 198, 333 and 525 g respectively. Oxygen consumption was measured in a respirometer of 18.8 L capacity and results show that at the same water temperature occurs an inverse relationship between body weight and oxygen consumption whereas for same body weight (W in kg the respiration rate varies proportionally with temperature rise (T in °C. The generalized equation of oxygen consumption (Ro in routine metabolism was determined as: Ro (mg O2 kg-1 h-1 = [85.229 + (10.03 T]-(221.344 W. The information it is analized with regard to establishing quantitative relationships that allow a more precise specification of the water flow requirements and renewal rates in open flow systems without oxygenation, considering aspects such as body weight, respiratory rate, temperature and stocking density.Se determinó la tasa de consumo de oxígeno de Oplegnathus insignis en cuatro grupos de peces bajo tres temperaturas diferentes: 13, 18 y 23°C. El peso promedio de cada grupo de peces fue de 9,5, 198, 333 y 523 g respectivamente. El consumo de oxígeno se determinó en un respirómetro de 18,8 L de capacidad y los resultados muestran que a una misma temperatura ocurre una relación inversa entre el peso corporal (W en kg y el consumo de oxígeno, mientras que para un mismo peso corporal la tasa respiratoria varía proporcionalmente con el ascenso de temperatura (T en °C. La ecuación generalizada que representa el consumo de oxígeno (Ro en metabolismo de rutina se determinó como: Ro (mg O2 kg-1 h-1 = [85.229 + (10.03 T]-(221.344 W. Se analizó la información en relación a establecer las relaciones cuantitativas que permitan una especificación más exacta de los requerimientos de flujo de agua y tasas de renovación en sistemas de flujo abierto y sin oxigenaci

  3. Which Instruments Can Detect Submaximal Physical and Functional Capacity in Patients With Chronic Nonspecific Back Pain? A Systematic Review

    NARCIS (Netherlands)

    van der Meer, Suzan; Trippolini, Maurizio A.; van der Palen, Job; Verhoeven, Jan; Reneman, Michiel F.

    2013-01-01

    Study Design. Systematic review. Objective. To evaluate the validity of instruments that claim to detect submaximal capacity when maximal capacity is requested in patients with chronic nonspecific musculoskeletal pain. Summary of Background Data. Several instruments have been developed to measure

  4. Oxygen (average seabed consumption) data collected using pressure gauge from the Drake Passage in part of the International Decade of Ocean Exploration / International Southern Ocean Studies / First Dynamic Response and Kinematics Experiment in the Drake Passage from 1976-02-08 to 1982-03-19 (NODC Accession 9000027)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Oxygen (average seabed consumption) data were collected using pressure gauge from the Drake Passage from February 8, 1976 to March 19, 1982. Data were submitted by...

  5. Bcl-xL-mediated remodeling of rod and cone synaptic mitochondria after postnatal lead exposure: electron microscopy, tomography and oxygen consumption.

    Science.gov (United States)

    Perkins, Guy A; Scott, Ray; Perez, Alex; Ellisman, Mark H; Johnson, Jerry E; Fox, Donald A

    2012-01-01

    Postnatal lead exposure produces rod-selective and Bax-mediated apoptosis, decreased scotopic electroretinograms (ERGs), and scotopic and mesopic vision deficits in humans and/or experimental animals. Rod, but not cone, inner segment mitochondria were considered the primary site of action. However, photoreceptor synaptic mitochondria were not examined. Thus, our experiments investigated the structural and functional effects of environmentally relevant postnatal lead exposure on rod spherule and cone pedicle mitochondria and whether Bcl-xL overexpression provided neuroprotection. C57BL/6N mice pups were exposed to lead only during lactation via dams drinking water containing lead acetate. The blood [Pb] at weaning was 20.6±4.7 µg/dl, which decreased to the control value by 2 months. To assess synaptic mitochondrial structural differences and vulnerability to lead exposure, wild-type and transgenic mice overexpressing Bcl-xL in photoreceptors were used. Electron microscopy, three-dimensional electron tomography, and retinal and photoreceptor synaptic terminal oxygen consumption (QO(2)) studies were conducted in adult control, Bcl-xL, lead, and Bcl-xL/lead mice. The spherule and pedicle mitochondria in lead-treated mice were swollen, and the cristae structure was markedly changed. In the lead-treated mice, the mitochondrial cristae surface area and volume (abundance: measure correlated with ATP (ATP) synthesis) were decreased in the spherules and increased in the pedicles. Pedicles also had an increased number of crista segments per volume. In the lead-treated mice, the number of segments/crista and fraction of cristae with multiple segments (branching) similarly increased in spherule and pedicle mitochondria. Lead-induced remodeling of spherule mitochondria produced smaller cristae with more branching, whereas pedicle mitochondria had larger cristae with more branching and increased crista junction (CJ) diameter. Lead decreased dark- and light-adapted photoreceptor

  6. Effect of membranes on oxygen transfer rate and consumption within a newly developed three-compartment bioartificial liver device: Advanced experimental and theoretical studies.

    Science.gov (United States)

    Hilal-Alnaqbi, Ali; Mourad, Abdel-Hamid I; Yousef, Basem F

    2014-01-01

    A mathematical model is developed to predict oxygen transfer in the fiber-in-fiber (FIF) bioartificial liver device. The model parameters are taken from the constructed and tested FIF modules. We extended the Krogh cylinder model by including one more zone for oxygen transfer. Cellular oxygen uptake was based on Michaelis-Menten kinetics. The effect of varying a number of important model parameters is investigated, including (1) oxygen partial pressure at the inlet, (2) the hydraulic permeability of compartment B (cell region), (3) the hydraulic permeability of the inner membrane, and (4) the oxygen diffusivity of the outer membrane. The mathematical model is validated by comparing its output against the experimentally acquired values of an oxygen transfer rate and the hydrostatic pressure drop. Three governing simultaneous linear differential equations are derived to predict and validate the experimental measurements, e.g., the flow rate and the hydrostatic pressure drop. The model output simulated the experimental measurements to a high degree of accuracy. The model predictions show that the cells in the annulus can be oxygenated well even at high cell density or at a low level of gas phase PG if the value of the oxygen diffusion coefficient Dm is 16 × 10(-5) . The mathematical model also shows that the performance of the FIF improves by increasing the permeability of polypropylene membrane (inner fiber). Moreover, the model predicted that 60% of plasma has access to the cells in the annulus within the first 10% of the FIF bioreactor axial length for a specific polypropylene membrane permeability and can reach 95% within the first 30% of its axial length. © 2013 International Union of Biochemistry and Molecular Biology, Inc.

  7. Acute Consumption of Bordo Grape Juice and Wine Improves Serum Antioxidant Status in Healthy Individuals and Inhibits Reactive Oxygen Species Production in Human Neuron-Like Cells.

    Science.gov (United States)

    Copetti, Cristiane; Franco, Fernanda Wouters; Machado, Eduarda da Rosa; Soquetta, Marcela Bromberger; Quatrin, Andréia; Ramos, Vitor de Miranda; Moreira, José Cláudio Fonseca; Emanuelli, Tatiana; Sautter, Cláudia Kaehler; Penna, Neidi Garcia

    2018-01-01

    Few studies investigated the biological effects of American grape cultivars. We investigated the metabolic response after acute consumption of grape juice or wine from Bordo grapes ( Vitis labrusca ) in a placebo-controlled crossover study with fifteen healthy volunteers. Blood samples were collected 1 hour after the intake of 100 mL of water, juice, or wine to measure TBARS, ABTS, FRAP, glucose, and uric acid levels. To evaluate differences in cellular response, intracellular reactive species production (DCFH-DA) and metabolic mitochondrial viability (MTT) were assessed after exposure of human neuron-like cells (SH-SY5Y) to juice or wine. Glycemia was reduced after juice or wine consumption, whereas blood levels of uric acid were reduced after juice consumption but increased after wine consumption. Juice and wine consumption reduced plasma lipid peroxidation and increased plasma antioxidant capacity (ABTS and FRAP assays). Furthermore, juice inhibited H 2 O 2 -induced intracellular production of reactive species (RS) and increased the viability of SH-SY5Y cells. In contrast, wine (dealcoholized) exhibited a per se effect by inducing the production of RS and reducing cell viability. These results indicate a positive impact of acute consumption of Bordo juice and wine on human oxidative status, whereas only juice had protective effects against oxidative stress-induced cytotoxicity.

  8. Acute Consumption of Bordo Grape Juice and Wine Improves Serum Antioxidant Status in Healthy Individuals and Inhibits Reactive Oxygen Species Production in Human Neuron-Like Cells

    Directory of Open Access Journals (Sweden)

    Cristiane Copetti

    2018-01-01

    Full Text Available Few studies investigated the biological effects of American grape cultivars. We investigated the metabolic response after acute consumption of grape juice or wine from Bordo grapes (Vitis labrusca in a placebo-controlled crossover study with fifteen healthy volunteers. Blood samples were collected 1 hour after the intake of 100 mL of water, juice, or wine to measure TBARS, ABTS, FRAP, glucose, and uric acid levels. To evaluate differences in cellular response, intracellular reactive species production (DCFH-DA and metabolic mitochondrial viability (MTT were assessed after exposure of human neuron-like cells (SH-SY5Y to juice or wine. Glycemia was reduced after juice or wine consumption, whereas blood levels of uric acid were reduced after juice consumption but increased after wine consumption. Juice and wine consumption reduced plasma lipid peroxidation and increased plasma antioxidant capacity (ABTS and FRAP assays. Furthermore, juice inhibited H2O2-induced intracellular production of reactive species (RS and increased the viability of SH-SY5Y cells. In contrast, wine (dealcoholized exhibited a per se effect by inducing the production of RS and reducing cell viability. These results indicate a positive impact of acute consumption of Bordo juice and wine on human oxidative status, whereas only juice had protective effects against oxidative stress-induced cytotoxicity.

  9. Iron Status in Chronic Heart Failure: Impact on Symptoms, Functional Class and Submaximal Exercise Capacity.

    Science.gov (United States)

    Enjuanes, Cristina; Bruguera, Jordi; Grau, María; Cladellas, Mercé; Gonzalez, Gina; Meroño, Oona; Moliner-Borja, Pedro; Verdú, José M; Farré, Nuria; Comín-Colet, Josep

    2016-03-01

    To evaluate the effect of iron deficiency and anemia on submaximal exercise capacity in patients with chronic heart failure. We undertook a single-center cross-sectional study in a group of stable patients with chronic heart failure. At recruitment, patients provided baseline information and completed a 6-minute walk test to evaluate submaximal exercise capacity and exercise-induced symptoms. At the same time, blood samples were taken for serological evaluation. Iron deficiency was defined as ferritin < 100 ng/mL or transferrin saturation < 20% when ferritin is < 800 ng/mL. Additional markers of iron status were also measured. A total of 538 heart failure patients were eligible for inclusion, with an average age of 71 years and 33% were in New York Heart Association class III/IV. The mean distance walked in the test was 285 ± 101 meters among those with impaired iron status, vs 322 ± 113 meters (P=.002). Symptoms during the test were more frequent in iron deficiency patients (35% vs 27%; P=.028) and the most common symptom reported was fatigue. Multivariate logistic regression analyses showed that increased levels of soluble transferrin receptor indicating abnormal iron status were independently associated with advanced New York Heart Association class (P < .05). Multivariable analysis using generalized additive models, soluble transferrin receptor and ferritin index, both biomarkers measuring iron status, showed a significant, independent and linear association with submaximal exercise capacity (P=.03 for both). In contrast, hemoglobin levels were not significantly associated with 6-minute walk test distance in the multivariable analysis. In patients with chronic heart failure, iron deficiency but not anemia was associated with impaired submaximal exercise capacity and symptomatic functional limitation. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  10. Prolonged administration of recombinant human erythropoietin increases submaximal performance more than maximal aerobic capacity

    DEFF Research Database (Denmark)

    Thomsen, J J; Rentsch, R L; Robach, P

    2007-01-01

    HuEpo treatment VO2max increased (Ptime-to-exhaustion (80% VO2max) was increased by 54.0 and 54.3% (Ptime point...... week 11), TTE was decreased by 26.8% as compared to pre rHuEpo administration. In conclusion, in healthy non-athlete subjects rHuEpo administration prolongs submaximal exercise performance by about 54% independently of the approximately 12% increase in VO2max....

  11. Cardiovascular response during submaximal underwater treadmill exercise in stroke patients.

    Science.gov (United States)

    Yoo, Jeehyun; Lim, Kil-Byung; Lee, Hong-Jae; Kwon, Yong-Geol

    2014-10-01

    To evaluate the cardiovascular response during head-out water immersion, underwater treadmill gait, and land treadmill gait in stroke patients. Ten stroke patients were recruited for underwater and land treadmill gait sessions. Each session was 40 minutes long; 5 minutes for standing rest on land, 5 minutes for standing rest in water or on treadmill, 20 minutes for treadmill walking in water or on land, 5 minutes for standing rest in water or on treadmill, and 5 minutes for standing rest on land. Blood pressure (BP) and heart rate (HR) were measured during each session. In order to estimate the cardiovascular workload and myocardial oxygen demand, the rate pressure product (RPP) value was calculated by multiplying systolic BP (SBP) by HR. SBP, DBP, mean BP (mBP), and RPP decreased significantly after water immersion, but HR was unchanged. During underwater and land treadmill gait, SBP, mBP, DBP, RPP, and HR increased. However, the mean maximum increases in BP, HR and RPP of underwater treadmill walking were significantly lower than that of land treadmill walking. Stroke patients showed different cardiovascular responses during water immersion and underwater gait as opposed to standing and treadmill-walking on land. Water immersion and aquatic treadmill gait may reduce the workload of the cardiovascular system. This study suggested that underwater treadmill may be a safe and useful option for cardiovascular fitness and early ambulation in stroke rehabilitation.

  12. Submaximal exercise thallium-201 SPECT for assessment of interventional therapy in patients with acute myocardial infarction

    International Nuclear Information System (INIS)

    Stewart, R.E.; Kander, N.; Juni, J.E.; Ellis, S.G.; O'Neill, W.W.; Schork, M.A.; Topol, E.J.; Schwaiger, M.

    1991-01-01

    Submaximal thallium-201 stress testing has been shown to provide important diagnostic and prognostic information in patients with acute myocardial infarction. The purpose of this investigation was to evaluate the diagnostic value of early submaximal stress testing and thallium-201 single photon emission computed tomography (SPECT) after interventional therapy. Scintigraphic results from 56 patients with infarctions, who underwent acute thrombolytic therapy, angioplasty, or both, were compared with late (6 weeks) functional outcome as assessed by radionuclide ventriculography and with results of discharge coronary angiography. A linear correlation was found between the extent of thallium-201 SPECT perfusion defect and late ventricular function (r = 0.74, p less than 0.01). Forty-two percent of patients with large SPECT perfusion defects had normal left ventricular ejection fractions, suggesting an overestimation of infarct size by early imaging. Sensitivity and specificity of thallium-201 SPECT for detection of coronary artery stenosis in noninfarct territories was 57% and 46%, respectively, indicating limited diagnostic definition of extent of underlying coronary artery disease. Results of follow-up coronary angiography showed a significant relationship between the size of the initial perfusion defect and early restenosis or reocclusion of the infarct artery. Thus the extent of early thallium-201 perfusion defects correlates with late functional outcome but appears to overestimate the degree of injury. Submaximal thallium-201 stress testing allows only limited characterization of underlying coronary artery disease. Early assessment of infarct size may identify a patient population at high risk for reocclusion of the infarct artery

  13. Characterization of Symmetry Properties of First Integrals for Submaximal Linearizable Third-Order ODEs

    Directory of Open Access Journals (Sweden)

    K. S. Mahomed

    2013-01-01

    Full Text Available The relationship between first integrals of submaximal linearizable third-order ordinary differential equations (ODEs and their symmetries is investigated. We obtain the classifying relations between the symmetries and the first integral for submaximal cases of linear third-order ODEs. It is known that the maximum Lie algebra of the first integral is achieved for the simplest equation and is four-dimensional. We show that for the other two classes they are not unique. We also obtain counting theorems of the symmetry properties of the first integrals for these classes of linear third-order ODEs. For the 5 symmetry class of linear third-order ODEs, the first integrals can have 0, 1, 2, and 3 symmetries, and for the 4 symmetry class of linear third-order ODEs, they are 0, 1, and 2 symmetries, respectively. In the case of submaximal linear higher-order ODEs, we show that their full Lie algebras can be generated by the subalgebras of certain basic integrals.

  14. High oxygen consumption rates and scale loss indicate elevated aggressive behaviour at low rearing density, while elevated brain serotonergic activity suggest chronic stress at high rearing densities in farmed rainbow trout Oncorhynchus mykiss

    DEFF Research Database (Denmark)

    Laursen, Danielle Caroline; Silva, P.I.M.; Larsen, Bodil Katrine

    2013-01-01

    of a previous study,where levels of crowding where determined using the spatial distribution of fish in two-tank systems. An un-crowded low density of 25 kg m−3, the highest density accepted by the fish without showing indications of crowding stress of 80 kg m−3 as the intermediate density, and the highest...... density accepted by the fish showing indications of crowding stress of 140 kg m−3 as the high density were investigated. The aimof the present study was to examine the effect of being held at these densities on indicators of welfare. This was achieved through oxygen consumption measurements using...

  15. Oxygen consumption and cytochrome exidase activity of axolotl limbs muscle tissue in restoration of regenerative ability suprressed by X-irradiation

    International Nuclear Information System (INIS)

    Teplits, N.A.

    1975-01-01

    The rate of oxygen use and activity of cytochrome oxidase in a homogenate of mitochondria and nuclei of muscle tissue of axolotl limbs after suppression of their regenerative capability by x irradiation and their restoration was studied experimentally. With suppression of the regenative capability the use of oxygen was depressed. Cytochrome oxidase activity in the homogenate and mitochondria decreased compared to that of the intact limb, in the nuclei of muscle tissue it was the same or greater. With restoration of the regenerative capability of the limbs the respiration rate of the homogenate and the mitochondria increased, accompanied by increased cytochrome oxidase activity. In the nuclei the cytochrome oxidase activity did not change in the blastema stage and sharply decreased in the limb formation state. (E.T.)

  16. Oxygen consumption and cytochrome exidase activity of axolotl limbs muscle tissue in restoration of regenerative ability suppressed by X-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Teplits, N A [AN SSSR, Moscow. Inst. Biologii Razvitiya

    1975-01-01

    The rate of oxygen use and activity of cytochrome oxidase in a homogenate of mitochondria and nuclei of muscle tissue of axolotl limbs after suppression of their regenerative capability by x irradiation and their restoration was studied experimentally. With suppression of the regenative capability the use of oxygen was depressed. Cytochrome oxidase activity in the homogenate and mitochondria decreased compared to that of the intact limb, in the nuclei of muscle tissue it was the same or greater. With restoration of the regenerative capability of the limbs the respiration rate of the homogenate and the mitochondria increased, accompanied by increased cytochrome oxidase activity. In the nuclei the cytochrome oxidase activity did not change in the blastema stage and sharply decreased in the limb formation state.

  17. Recumbent Stepper Submaximal Test response is reliable in adults with and without stroke.

    Directory of Open Access Journals (Sweden)

    David R Wilson

    Full Text Available The purpose of the present study was to determine the reliability of the exercise response (predicted peak VO2 using the total body recumbent stepper (TBRS submaximal exercise test in: 1 healthy adults 20-70 years of age and 2 adults participating in inpatient stroke rehabilitation. We hypothesized that the predicted peak VO2 (Visit 1 would have an excellent relationship (r > 0.80 to predicted peak VO2 (Visit 2. We also wanted to test whether the exercise response at Visit 1 and Visit 2 would be significantly different.Healthy adults were recruited from the Kansas City metro area. Stroke participants were recruited during their inpatient rehabilitation stay. Eligible participants completed 2 TBRS submaximal exercise tests between 24 hours and 5 days at similar times of day.A total of 70 participants completed the study. Healthy adults (n = 50 were 36 M, 38.1 ± 10.1 years and stroke participants (n = 20 were 15 M, 62.5 ± 11.8 years of age. The exercise response was reliable for healthy adults (r = 0.980, p<0.01 and stroke participants (r = 0.987, p<0.01 between Visit 1 and Visit 2. Repeated Measures ANOVA showed a significant difference in predicted values between the two visits for healthy adults (47.2 ± 8.4 vs 47.7 ± 8.5 mL∙kg-1∙min-1; p = 0.04 but not for stroke participants (25.0 ± 9.9 vs 25.3 ± 11.4 mL∙kg-1∙min-1; p = 0.65.These results suggest that the exercise response is reliable using the TBRS submaximal exercise test in this cohort of healthy adults and stroke participants.

  18. Abnormal heart rate recovery and deficient chronotropic response after submaximal exercise in young Marfan syndrome patients.

    Science.gov (United States)

    Peres, Paulo; Carvalho, Antônio C; Perez, Ana Beatriz A; Medeiros, Wladimir M

    2016-10-01

    Marfan syndrome patients present important cardiac structural changes, ventricular dysfunction, and electrocardiographic changes. An abnormal heart rate response during or after exercise is an independent predictor of mortality and autonomic dysfunction. The aim of the present study was to compare heart rate recovery and chronotropic response obtained by cardiac reserve in patients with Marfan syndrome subjected to submaximal exercise. A total of 12 patients on β-blocker therapy and 13 off β-blocker therapy were compared with 12 healthy controls. They were subjected to submaximal exercise with lactate measurements. The heart rate recovery was obtained in the first minute of recovery and corrected for cardiac reserve and peak lactate concentration. Peak heart rate (141±16 versus 155±17 versus 174±8 bpm; p=0.001), heart rate reserve (58.7±9.4 versus 67.6±14.3 versus 82.6±4.8 bpm; p=0.001), heart rate recovery (22±6 versus 22±8 versus 34±9 bpm; p=0.001), and heart rate recovery/lactate (3±1 versus 3±1 versus 5±1 bpm/mmol/L; p=0.003) were different between Marfan groups and controls, respectively. All the patients with Marfan syndrome had heart rate recovery values below the mean observed in the control group. The absolute values of heart rate recovery were strongly correlated with the heart rate reserve (r=0.76; p=0.001). Marfan syndrome patients have reduced heart rate recovery and chronotropic deficit after submaximal exercise, and the chronotropic deficit is a strong determinant of heart rate recovery. These changes are suggestive of autonomic dysfunction.

  19. Experimental knee pain impairs submaximal force steadiness in isometric, eccentric, and concentric muscle actions.

    Science.gov (United States)

    Rice, David A; McNair, Peter J; Lewis, Gwyn N; Mannion, Jamie

    2015-09-12

    Populations with knee joint damage, including arthritis, have noted impairments in the regulation of submaximal muscle force. It is difficult to determine the exact cause of such impairments given the joint pathology and associated neuromuscular adaptations. Experimental pain models that have been used to isolate the effects of pain on muscle force regulation have shown impaired force steadiness during acute pain. However, few studies have examined force regulation during dynamic contractions, and these findings have been inconsistent. The goal of the current study was to examine the effect of experimental knee joint pain on submaximal quadriceps force regulation during isometric and dynamic contractions. The study involved fifteen healthy participants. Participants were seated in an isokinetic dynamometer. Knee extensor force matching tasks were completed in isometric, eccentric, and concentric muscle contraction conditions. The target force was set to 10 % of maximum for each contraction type. Hypertonic saline was then injected into the infrapatella fat pad to generate acute joint pain. The force matching tasks were repeated during pain and once more 5 min after pain had subsided. Hypertonic saline resulted in knee pain with an average peak pain rating of 5.5 ± 2.1 (0-10 scale) that lasted for 18 ± 4 mins. Force steadiness significantly reduced during pain across all three muscle contraction conditions. There was a trend to increased force matching error during pain but this was not significant. Experimental knee pain leads to impaired quadriceps force steadiness during isometric, eccentric, and concentric contractions, providing further evidence that joint pain directly affects motor performance. Given the established relationship between submaximal muscle force steadiness and function, such an effect may be detrimental to the performance of tasks in daily life. In order to restore motor performance in people with painful arthritic conditions of the

  20. Effects of Pedal Speed and Crank Length on Pedaling Mechanics during Submaximal Cycling

    Science.gov (United States)

    BARRATT, PAUL RICHARD; MARTIN, JAMES C.; ELMER, STEVE J.; KORFF, THOMAS

    2016-01-01

    ABSTRACT During submaximal cycling, the neuromuscular system has the freedom to select different intermuscular coordination strategies. From both a basic science and an applied perspective, it is important to understand how the central nervous system adjusts pedaling mechanics in response to changes in pedaling conditions. Purpose To determine the effect of changes in pedal speed (a marker of muscle shortening velocity) and crank length (a marker of muscle length) on pedaling mechanics during submaximal cycling. Methods Fifteen trained cyclists performed submaximal isokinetic cycling trials (90 rpm, 240 W) using pedal speeds of 1.41 to 1.61 m·s−1 and crank lengths of 150 to 190 mm. Joint powers were calculated using inverse dynamics. Results Increases in pedal speed and crank length caused large increases knee and hip angular excursions and velocities (P 0.05). Joint moments and joint powers were less affected by changes in the independent variables, but some interesting effects and trends were observed. Most noteworthy, knee extension moments and powers tended to decrease, whereas hip extension power tended to increase with an increase in crank length. Conclusions The distribution of joint moments and powers is largely maintained across a range of pedaling conditions. The crank length induced differences in knee extension moments, and powers may represent a trade-off between the central nervous system’s attempts to simultaneously minimize muscle metabolic and mechanical stresses. These results increase our understanding of the neural and mechanical mechanisms underlying multi-joint task performance, and they have practical relevance to coaches, athletes, and clinicians. PMID:26559455

  1. Warm-Up Exercises May Not Be So Important for Enhancing Submaximal Running Performance.

    Science.gov (United States)

    Takizawa, Kazuki; Yamaguchi, Taichi; Shibata, Keisuke

    2018-05-01

    Takizawa, K, Yamaguchi, T, and Shibata, K. Warm-up exercises may not be so important for enhancing submaximal running performance. J Strength Cond Res 32(5): 1383-1390, 2018-The purpose of this study was to determine an appropriate warm-up intensity for enhancing performance in submaximal running at 90% vV[Combining Dot Above]O2max (it assumes 3,000-5,000 m in track events). Seven trained male university athletes took part in this study (age: 21.3 ± 2.1 years, height: 169.3 ± 4.7 cm, body mass: 58.4 ± 5.6 kg, V[Combining Dot Above]O2max: 73.33 ± 5.46 ml·kg·min). Each subject ran on a treadmill at 90% vV[Combining Dot Above]O2max until exhaustion after 1 of 4 warm-up treatments. The 4 warm-up treatments were no warm-up, 15 minutes running at 60% vV[Combining Dot Above]O2max, at 70% vV[Combining Dot Above]O2max, and at 80% vV[Combining Dot Above]O2max. The running performance was evaluated by time to exhaustion (TTE). V[Combining Dot Above]O2, and vastus lateralis muscle temperature were also measured. There were no significant differences in TTE among the warm-up exercises (p > 0.05). V[Combining Dot Above]O2 in no warm-up showed slower reaction than the other warm-up exercises. Regarding, the vastus lateralis muscle temperature immediately after warm-up, no warm-up was significantly (p warm-up exercises. Our results suggested that submaximal running performance was not affected by the presence or absence of a warm-up or by warm-up intensity, although physiological changes occurred.

  2. The Impact of a Submaximal Level of Exercise on Balance Performance in Older Persons

    Directory of Open Access Journals (Sweden)

    Hani Asilah Alias

    2014-01-01

    Full Text Available Objective. The purpose of this study was to determine the impact of a submaximal level of exercise on balance performance under a variety of conditions. Material and Method. Thirteen community-dwelling older persons with intact foot sensation (age = 66.69 ± 8.17 years, BMI = 24.65 ± 4.08 kg/m2, female, n=6 volunteered to participate. Subjects’ balance performances were measured using the Modified Clinical Test of Sensory Integration of Balance (mCTSIB at baseline and after test, under four conditions of stance: (1 eyes-opened firm-surface (EOF, (2 eyes-closed firm-surface (ECF, (3 eyes-opened soft-surface (EOS, and (4 eyes-closed soft-surface (ECS. The 6-minute walk test (6MWT protocol was used to induce the submaximal level of exercise. Data was analyzed using the Wilcoxon Signed-Rank Test. Results. Balance changes during EOF (z=0.00, P=1.00 and ECF (z=-1.342, P=0.180 were not significant. However, balance changes during EOS (z=-2.314, P=0.021 and ECS (z=-3.089, P=0.02 were significantly dropped after the 6MWT. Conclusion. A submaximal level of exercise may influence sensory integration that in turn affects balance performance, particularly on an unstable surface. Rehabilitation should focus on designing intervention that may improve sensory integration among older individuals with balance deterioration in order to encourage functional activities.

  3. Characterization of sludge properties for sewage treatment in a practical-scale down-flow hanging sponge reactor: oxygen consumption and removal of organic matter, ammonium, and sulfur.

    Science.gov (United States)

    Nomoto, Naoki; Hatamoto, Masashi; Ali, Muntjeer; Jayaswal, Komal; Iguchi, Akinori; Okubo, Tsutomu; Takahashi, Masanobu; Kubota, Kengo; Tagawa, Tadashi; Uemura, Shigeki; Yamaguchi, Takashi; Harada, Hideki

    2018-02-01

    The characteristics of sludge retained in a down-flow hanging sponge reactor were investigated to provide a better understanding of the sewage treatment process in the reactor. The organic removal and sulfur oxidation conditions were found to differ between the first layer and the following three layers. It was found that 63% and 59% of the organic matter was removed in the first layer, even though the hydraulic retention time was only 0.2 h. It is thought that the organic removal resulted from aerobic and anaerobic biodegradation on the sponge medium. The sulfate concentration increased 1.5-1.9-fold in the first layer, with almost no subsequent change in the second to fourth layers. It was shown that oxidation of sulfide in the influent was completed in the first layer. The result of the oxygen uptake rate test with an ammonium nitrogen substrate suggested that the ammonium oxidation rate was affected by the condition of dissolved oxygen (DO) or oxidation-reduction potential (ORP).

  4. Correlations between plasma noradrenaline concentrations, antioxidants, and neutrophil counts after submaximal resistance exercise in men

    Science.gov (United States)

    Ramel, A; Wagner, K; Elmadfa, I

    2004-01-01

    Objectives: To investigate noradrenaline concentrations, neutrophil counts, plasma antioxidants, and lipid oxidation products before and after acute resistance exercise. Methods: 17 male participants undertook a submaximal resistance exercise circuit (10 exercises; 75% of the one repetition maximum; mean (SD) exercise time, 18.6 (1.1) minutes). Blood samples were taken before and immediately after exercise and analysed for plasma antioxidants, noradrenaline, neutrophils, and lipid oxidation products. Wilcoxon's signed-rank test and Pearson's correlation coefficient were used for calculations. Results: Neutrophils, noradrenaline, fat soluble antioxidants, and lipid oxidation products increased after exercise. Noradrenaline concentrations were associated with higher antioxidant concentrations. Neutrophils were related to higher concentrations of conjugated dienes. Conclusions: Submaximal resistance exercise increases plasma antioxidants. This might reflect enhanced antioxidant defence in response to the oxidative stress of exercise, though this is not efficient for inhibiting lipid oxidation. The correlation between noradrenaline concentrations and plasma antioxidants suggests a modulating role of the stress hormone. Neutrophils are a possible source of oxidative stress after resistance exercise. PMID:15388566

  5. Effect of a submaximal half-squats warm-up program on vertical jumping ability.

    Science.gov (United States)

    Gourgoulis, Vassilios; Aggeloussis, Nickos; Kasimatis, Panagiotis; Mavromatis, Giorgos; Garas, Athanasios

    2003-05-01

    The purpose of the current research was to study the effect of a warm-up program including submaximal half-squats on vertical jumping ability. Twenty physically active men participated in the study. Each subject performed 5 sets of half-squats with 2 repetitions at each of the following intensities: 20, 40, 60, 80, and 90% of the 1 repetition maximum (1RM) load. Prior to the first set and immediately after the end of the last set, the subjects performed 2 countermovement jumps on a Kistler force platform; the primary goal was to jump as high as possible. The results showed that mean vertical jumping ability improved by 2.39% after the warm-up period. Subjects were then divided into 2 groups according to their 1RM values for the half-squat. Subjects with greater maximal strength ability improved their vertical jumping ability (4.01%) more than did subjects with lower maximal strength (0.42%). A warm-up protocol including half-squats with submaximal loads and explosive execution can be used for short-term improvements of vertical jumping performance, and this effect is greater in athletes with a relatively high strength ability.

  6. Cognitive Performance Enhancement Induced by Caffeine, Carbohydrate and Guarana Mouth Rinsing during Submaximal Exercise

    Directory of Open Access Journals (Sweden)

    Laura Pomportes

    2017-06-01

    Full Text Available The aim of this study was to investigate the influence of serial mouth rinsing (MR with nutritional supplements on cognitive performance (i.e., cognitive control and time perception during a 40-min submaximal exercise. Twenty-four participants completed 4 counterbalanced experimental sessions, during which they performed MR with either placebo (PL, carbohydrate (CHO: 1.6 g/25 mL, guarana complex (GUAc: 0.4 g/25 mL or caffeine (CAF: 67 mg/25 mL before and twice during exercise. The present study provided some important new insights regarding the specific changes in cognitive performance induced by nutritional supplements. The main results were: (1 CHO, CAF and GUA MR likely led participants to improve temporal performance; (2 CAF MR likely improved cognitive control; and (3 CHO MR led to a likely decrease in subjective perception of effort at the end of the exercise compared to PL, GUA and CAF. Moreover, results have shown that performing 40-min submaximal exercise enhances information processing in terms of both speed and accuracy, improves temporal performance and does not alter cognitive control. The present study opens up new perspectives regarding the use of MR to optimize cognitive performance during physical exercise.

  7. Myocardial 201Tl washout after combined dipyridamole submaximal exercise stress: Reference values from different patient groups

    International Nuclear Information System (INIS)

    Fridrich, L.

    1989-01-01

    Dipyridamole stress is favorable in patients unable to exercise maximally for 201 Tl myocardial scintigraphy. Aside from an analysis of uptake defects, proper washout analysis can be limited by heart rate variations when isolated dipyridamole stress is used. Heart rate standardized 201 Tl washout kinetics after a combined dipyridamole and submaximal exercise stress protocol (CDSE), feasible in elderly patients as well as in patients with peripheral artery disease, were therefore studied to investigate the 201 Tl washout after CDSE in differently defined patient groups: Group I comprised 19 patients with documented heart disease and angiographically excluded coronary artery disease (CAD); group II contained 17 patients with a very low likelihood of CAD determined by both normal exercise radionuclide ventriculography and normal 201 Tl uptake. Group III comprised 56 patients with a 50% pretest likelihood of CAD but normal 201 Tl uptake. Mean washout values were nearly identical in all groups. Despite similar uptake patterns, however, washout standardized by CDSE was significantly lower than the normal washout values after maximal treadmill exercise. Thus an obviously lower 201 Tl washout after CDSE than after maximal treadmill exercise must be considered if washout analysis criteria after dipyridamole are applied to evaluate ischemic heart disease. Nevertheless, heart rate elevation achieved by additional submaximal exercise stress seems necessary, adequate and clinically safe for standardisation of washout analysis in dipyridamole 201 Tl scintigraphy. (orig.)

  8. Activation of selected shoulder muscles during unilateral wall and bench press tasks under submaximal isometric effort.

    Science.gov (United States)

    Tucci, Helga T; Ciol, Marcia A; de Araújo, Rodrigo C; de Andrade, Rodrigo; Martins, Jaqueline; McQuade, Kevin J; Oliveira, Anamaria S

    2011-07-01

    Controlled laboratory study. To assess the activation of 7 shoulder muscles under 2 closed kinetic chain (CKC) tasks for the upper extremity using submaximal isometric effort, thus providing relative quantification of muscular isometric effort for these muscles across the CKC exercises, which may be applied to rehabilitation protocols for individuals with shoulder weakness. CKC exercises favor joint congruence, reduce shear load, and promote joint dynamic stability. Additionally, knowledge about glenohumeral and periscapular muscle activity elicited during CKC exercises may help clinicians to design protocols for shoulder rehabilitation. Using surface electromyography, activation level was measured across 7 shoulder muscles in 20 healthy males, during the performance of a submaximal isometric wall press and bench press. Signals were normalized to the maximal voluntary isometric contraction, and, using paired t tests, data were analyzed between the exercises for each muscle. Compared to the wall press, the bench press elicited higher activity for most muscles, except for the upper trapezius. Levels of activity were usually low but were above 20% maximal voluntary isometric contraction for the serratus anterior on both tasks, and for the long head triceps brachii on the bench press. Both the bench press and wall press, as performed in this study, led to relatively low EMG activation levels for the muscles measured and may be considered for use in the early phases of rehabilitation.

  9. Cold water immersion enhances recovery of submaximal muscle function after resistance exercise.

    Science.gov (United States)

    Roberts, Llion A; Nosaka, Kazunori; Coombes, Jeff S; Peake, Jonathan M

    2014-10-15

    We investigated the effect of cold water immersion (CWI) on the recovery of muscle function and physiological responses after high-intensity resistance exercise. Using a randomized, cross-over design, 10 physically active men performed high-intensity resistance exercise followed by one of two recovery interventions: 1) 10 min of CWI at 10°C or 2) 10 min of active recovery (low-intensity cycling). After the recovery interventions, maximal muscle function was assessed after 2 and 4 h by measuring jump height and isometric squat strength. Submaximal muscle function was assessed after 6 h by measuring the average load lifted during 6 sets of 10 squats at 80% of 1 repetition maximum. Intramuscular temperature (1 cm) was also recorded, and venous blood samples were analyzed for markers of metabolism, vasoconstriction, and muscle damage. CWI did not enhance recovery of maximal muscle function. However, during the final three sets of the submaximal muscle function test, participants lifted a greater load (P work during subsequent training sessions, which could enhance long-term training adaptations. Copyright © 2014 the American Physiological Society.

  10. Effects of posture on upper and lower limb peripheral resistance following submaximal cycling.

    Science.gov (United States)

    Swan, P D; Spitler, D L; Todd, M K; Maupin, J L; Lewis, C L; Darragh, P M

    1989-09-01

    The purpose of this study was to determine postural effects on upper and lower limb peripheral resistance (PR) after submaximal exercise. Twelve subjects (six men and six women) completed submaximal cycle ergometer tests (60% age-predicted maximum heart rate) in the supine and upright seated positions. Each test included 20 minutes of rest, 20 minutes of cycling, and 15 minutes of recovery. Stroke volume and heart rate were determined by impedance cardiography, and blood pressure was measured by auscultation during rest, immediately after exercise, and at minutes 1-5, 7.5, 10, 12.5, and 15 of recovery. Peripheral resistance was calculated from values of mean arterial pressure and cardiac output. No significant (p less than 0.05) postural differences in PR were noted during rest for either limb. Immediately after exercise, PR decreased (55% to 61%) from resting levels in both limbs, independent of posture. Recovery ankle PR values were significantly different between postures. Upright ankle PR returned to 92% of the resting level within four minutes of recovery, compared to 76% of the resting level after 15 minutes in the supine posture. Peripheral resistance values in the supine and upright arm were not affected by posture and demonstrated a gradual pattern of recovery similar to the supine ankle recovery response (85% to 88% of rest within 15 minutes). The accelerated recovery rate of PR after upright exercise may result from local vasoconstriction mediated by a central regulatory response to stimulation from gravitational pressure on lower body circulation.

  11. Reliability of heart rate variability threshold and parasympathetic reactivation after a submaximal exercise test

    Directory of Open Access Journals (Sweden)

    Carlos Janssen Gomes da Cruz

    Full Text Available Abstract The objective of this study was to evaluate reproducibility of heart rate variability threshold (HRVT and parasympathetic reactivation in physically active men (n= 16, 24.3 ± 5.1 years. During the test, HRVT was assessed by SD1 and r-MSSD dynamics. Immediately after exercise, r-MSSD was analyzed in segments of 60 seconds for a period of five minutes. High absolute and relatively reproducible analysis of HRVT were observed, as assessed by SD1 and r-MSSD dynamics (ICC = 0.92, CV = 10.8, SEM = 5.8. During the recovery phase, a moderate to high reproducibility was observed for r-MSSD from the first to the fifth minute (ICC = 0.69-0.95, CV = 7.5-14.2, SEM = 0.07-1.35. We conclude that HRVT and r-MSSD analysis after a submaximal stress test are highly reproducible measures that might be used to assess the acute and chronic effects of exercise training on cardiac autonomic modulation during and/or after a submaximal stress test.

  12. Cognitive Performance Enhancement Induced by Caffeine, Carbohydrate and Guarana Mouth Rinsing during Submaximal Exercise.

    Science.gov (United States)

    Pomportes, Laura; Brisswalter, Jeanick; Casini, Laurence; Hays, Arnaud; Davranche, Karen

    2017-06-09

    The aim of this study was to investigate the influence of serial mouth rinsing (MR) with nutritional supplements on cognitive performance (i.e., cognitive control and time perception) during a 40-min submaximal exercise. Twenty-four participants completed 4 counterbalanced experimental sessions, during which they performed MR with either placebo (PL), carbohydrate (CHO: 1.6 g/25 mL), guarana complex (GUAc: 0.4 g/25 mL) or caffeine (CAF: 67 mg/25 mL) before and twice during exercise. The present study provided some important new insights regarding the specific changes in cognitive performance induced by nutritional supplements. The main results were: (1) CHO, CAF and GUA MR likely led participants to improve temporal performance; (2) CAF MR likely improved cognitive control; and (3) CHO MR led to a likely decrease in subjective perception of effort at the end of the exercise compared to PL, GUA and CAF. Moreover, results have shown that performing 40-min submaximal exercise enhances information processing in terms of both speed and accuracy, improves temporal performance and does not alter cognitive control. The present study opens up new perspectives regarding the use of MR to optimize cognitive performance during physical exercise.

  13. GABAA Receptor-Mediated Bidirectional Control of Synaptic Activity, Intracellular Ca2+, Cerebral Blood Flow, and Oxygen Consumption in Mouse Somatosensory Cortex In Vivo

    DEFF Research Database (Denmark)

    Jessen, Sanne Barsballe; Brazhe, Alexey; Lind, Barbara Lykke

    2015-01-01

    Neural activity regulates local increases in cerebral blood flow (ΔCBF) and the cortical metabolic rate of oxygen (ΔCMRO2) that constitutes the basis of BOLD functional neuroimaging signals. Glutamate signaling plays a key role in brain vascular and metabolic control; however, the modulatory effect...... of GABA is incompletely understood. Here we performed in vivo studies in mice to investigate how THIP (which tonically activates extrasynaptic GABAARs) and Zolpidem (a positive allosteric modulator of synaptic GABAARs) impact stimulation-induced ΔCBF, ΔCMRO2, local field potentials (LFPs), and fluorescent...... cytosolic Ca2+ transients in neurons and astrocytes. Low concentrations of THIP increased ΔCBF and ΔCMRO2 at low stimulation frequencies. These responses were coupled to increased synaptic activity as indicated by LFP responses, and to Ca2+ activities in neurons and astrocytes. Intermediate and high...

  14. Oxygen consumption of Litopenaeus vannamei juveniles in heterotrophic medium with zero water exchange Consumo de oxigênio de juvenis de Litopenaeus vannamei em meio heterotrófico sem renovação de água

    Directory of Open Access Journals (Sweden)

    Luis Vinatea

    2009-05-01

    Full Text Available This work aimed at determining the dissolved oxygen consumption rate of Litopenaeus vannamei juveniles maintained in a microbial biofloc raceway system at high density with no aeration. Three 4 L bottles were filled for each treatment, sealed hermetically, and placed in an enclosed greenhouse raceway system. Four shrimp (13.2±1.42 g were assigned to two sets of the bottles, which underwent the following treatments: light conditions with no shrimp; dark conditions with no shrimp; light conditions with shrimp; and dark conditions with shrimp. Dissolved oxygen content was measured every 10 min for 30 min. A quadratic behavior was observed in dissolved oxygen concentration over time. Significant differences for oxigen consumption were observed only at 10 and 20 min between shrimp maintained in the dark and those under light conditions. At 10 min, a higher value was observed in shrimp maintained under light, and at 20 min, in the dark. Significant differences between 10 and 20 min and between 10 and 30 min were observed when oxygen consumption was analyzed over time in the presence of light. Under dark conditions there were significant differences only between 20 and 30 min. Lethal oxygen concentration (0.65 mg L-1 would be reached in less than one hour either under light or dark conditions with no aeration.O objetivo deste trabalho foi determinar o consumo de oxigênio dissolvido (OD de juvenis de Litopenaeus vannamei mantidos em sistema de cultivo de bioflocs bacterianos em alta densidade e ausência de aeração. Três garrafas de 4 L foram preenchidas para cada tratamento, fechadas hermeticamente e colocadas em sistema de cultivo fechado. Quatro camarões (13,2±1,42 g foram colocados em dois dos conjuntos de garrafas. Os tratamentos aplicados foram: luminosidade, sem camarões; escuro, sem camarões; luminosidade, com camarões; escuro, com camarões. A concentração de oxigênio dissolvido foi determinada a cada 10 min durante 30 min. Foi

  15. High-dose inhaled salbutamol has no acute effects on aerobic capacity or oxygen uptake kinetics in healthy trained men

    DEFF Research Database (Denmark)

    Elers, J; Mørkeberg, Jakob; Jansen, T

    2012-01-01

    enrolled nine healthy well-trained men in a randomized, blinded, placebo-controlled crossover study. Subjects were randomized to inhalation of 40 puffs of 0.2 mg salbutamol or two placebo tablets and performed an incremental test to exhaustion and three submaximal tests at 75% of peak power to determine...... oxygen uptake kinetics. During the incremental test, there were no effects of inhaled salbutamol on VO(2max) in absolute or relative terms, and no effect on peak power and lactate threshold. During the submaximal test, we found no effects on the time constant, time delay, the mean response time or O(2...

  16. EFFECT OF ENERGY EXPENDITURE AND TRAINING STATUS ON LEPTIN RESPONSE TO SUB-MAXIMAL CYCLING

    Directory of Open Access Journals (Sweden)

    Anissa Bouassida

    2009-06-01

    Full Text Available We examined the leptin response and related hormones during and after two sub-maximal exercise protocols in trained and untrained subjects. During this study, plasma concentrations of leptin [Lep], insulin [I], cortisol [C], growth hormone [GH], glucose [G] and lactate [La] were measured. 7 elite volleyball trained players (TR and 7 untrained (UTR subjects (percent body fat: 13.2 ± 1.8 versus 15.7 ± 1.0, p < 0.01, respectively were examined after short and prolonged sub-maximal cycling exercise protocols (SP and PP. Venous blood samples were collected before each protocol, during, at the end, and after 2 and 24 h of recovery. SP and PP energy expenditures ranged from 470 ± 60 to 740 ± 90 kcal for TR and from 450 ± 60 to 710 ± 90 kcal for UTR, respectively. [Lep] was related to body fat percentage and body fat mass in TR (r = 0. 84, p < 0.05 and r = 0.93, p < 0.01 and in UTR (r = 0.89, p < 0.01 and r = 0.92, p < 0. 01, respectively. [Lep] did not change significantly during both protocols for both groups but was lower (p < 0.05 in all sampling in TR when compared to UTR. Plasma [I] decreased (p < 0.01 and [GH] increased (p < 0.01 significantly during both SP and PP and these hormones remained lower (I: p < 0.01 and higher (GH: p < 0.01 than pre-exercise levels after a 2-h recovery period, returning to base-line at 24-h recovery. Plasma [La] increased (p < 0.01 during both protocols for TR and UTR. There was no significant change in [C] and [G] during and after both protocols for all subjects. It is concluded that 1 leptin is not sensitive to acute short or prolonged sub-maximal exercises (with energy expenditure under 800 kcal in volleyball/ anaerobically trained athletes as in untrained subjects, 2 volleyball athletes showed significantly lower resting and exercise leptin response with respect to untrained subjects and 3 it appears that in these anaerobically trained athletes leptin response to exercise is more sensitive to the level of

  17. Which Instruments can Detect Submaximal Physical and Functional Capacity in Patients With Chronic Nonspecific Back Pain?: A Systematic Review

    NARCIS (Netherlands)

    van der Meer, Suzan; Trippolini, Maurizio A.; van der Palen, Jacobus Adrianus Maria; Verhoeven, Jan; Reneman, Michiel F.

    2013-01-01

    Objective. To evaluate the validity of instruments that claim to detect submaximal capacity when maximal capacity is requested in patients with chronic nonspecific musculoskeletal pain. Summary of Background Data. Several instruments have been developed to measure capacity in patients with chronic

  18. The association between submaximal quadriceps force steadiness and the knee adduction moment during walking in patients with knee osteoarthritis

    DEFF Research Database (Denmark)

    Sørensen, Tina Juul; Langberg, Henning; Aaboe, Jens

    2011-01-01

    in this population. METHODS: Forty-one patients with knee OA (34 females and 7 males) were included in the study. Submaximal isometric quadriceps force steadiness was measured during a force target-tracking task. Peak knee adduction moments during ambulation were measured using a 3-dimensional gait analysis system...

  19. Effect of moderate dietary restriction on visceral organ weight, hepatic oxygen consumption, and metabolic proteins associated with energy balance in mature pregnant beef cows.

    Science.gov (United States)

    Wood, K M; Awda, B J; Fitzsimmons, C; Miller, S P; McBride, B W; Swanson, K C

    2013-09-01

    Twenty-two nonlactating multiparous pregnant beef cows (639 ± 68 kg) were used to investigate the effect of dietary restriction on the abundance of selected proteins regulating cellular energy metabolism. Cows were fed at either 85% (n = 11; LOW) or 140% (n = 11; HIGH) of total NE requirements. The diet consisted of a haylage-based total mixed ration containing 20% wheat straw. Cows were slaughtered by block (predicted date of parturition), beginning 83 d after the initiation of dietary treatments and every week thereafter for 6 wk, such that each block was slaughtered at approximately 250 d of gestation. Tissue samples from liver, kidney, sternomandibularis muscle, ruminal papilli (ventral sac), pancreas, and small intestinal muscosa were collected at slaughter and snap frozen in liquid N2. Western blots were conducted to quantify abundance of proliferating cell nuclear antigen (PCNA), ATP synthase, ubiquitin, and Na/K+ ATPase for all tissues; PPARγ, PPARγ coactivator 1 α (PGC-1α), and 5´-adenosine monophosphate-activated protein kinase (AMPK) and the activated form phosphorylated-AMPK (pAMPK) for liver, muscle, and rumen; phosphoenolpyruvate carboxykinase (PEPCK) for liver and kidney; and uncoupling protein 2 (UCP2) for liver. Statistical analysis was conducted using Proc Mixed in SAS and included the fixed effects of dietary treatment, cow age, block, and the random effect of pen. Dietary treatments resulted in cows fed HIGH having greater (P ≤ 0.04) ADG and final BW than cows fed LOW. Abundance of ubiquitin in muscle was greater (P = 0.009) in cows fed LOW, and PCG-1 α in liver was greater (P = 0.03) in cows fed HIGH. Hepatic O2 consumption was greater in HIGH (P ≤ 0.04). Feed intake can influence the abundance of important metabolic proteins and suggest that protein degradation may increase in muscle from moderately nutrient restricted cows and that energy metabolism in liver increases in cows fed above NE requirements.

  20. Brief note about plasma catecholamines kinetics and submaximal exercise in untrained standardbreds

    Directory of Open Access Journals (Sweden)

    Paolo Baragli

    2010-03-01

    Full Text Available Four untrained standardbred horses performed a standardized exercise test on the treadmill and an automated blood collection system programmed to obtain blood samples every 15 s was used for blood collection in order to evaluate the kinetics of adrenaline and noradrenaline. The highest average values obtained for adrenaline and noradrenaline were 15.0 ± 3.0 and 15.8 ± 2.8 nmol/l respectively, with exponential accumulation of adrenaline (r = 0.977 and noradrenaline (r = 0.976 during the test. Analysis of the correlation between noradrenaline and adrenaline for each phase of the test shows that correlation coefficient decreases as the intensity of exercise increases (from r = 0.909 to r = 0.788. This suggests that during submaximal exercise, the process for release, distribution and clearance of adrenaline into blood circulation differs from that of noradrenaline.

  1. Investigation of the Relationship Between Electrical Stimulation Frequency and Muscle Frequency Response Under Submaximal Contractions.

    Science.gov (United States)

    Papcke, Caluê; Krueger, Eddy; Olandoski, Marcia; Nogueira-Neto, Guilherme Nunes; Nohama, Percy; Scheeren, Eduardo Mendonça

    2018-03-25

    Neuromuscular electrical stimulation (NMES) is a common tool that is used in clinical and laboratory experiments and can be combined with mechanomyography (MMG) for biofeedback in neuroprostheses. However, it is not clear if the electrical current applied to neuromuscular tissues influences the MMG signal in submaximal contractions. The objective of this study is to investigate whether the electrical stimulation frequency influences the mechanomyographic frequency response of the rectus femoris muscle during submaximal contractions. Thirteen male participants performed three maximal voluntary isometric contractions (MVIC) recorded in isometric conditions to determine the maximal force of knee extensors. This was followed by the application of nine modulated NMES frequencies (20, 25, 30, 35, 40, 45, 50, 75, and 100 Hz) to evoke 5% MVIC. Muscle behavior was monitored by the analysis of MMG signals, which were decomposed into frequency bands by using a Cauchy wavelet transform. For each applied electrical stimulus frequency, the mean MMG spectral/frequency response was estimated for each axis (X, Y, and Z axes) of the MMG sensor with the values of the frequency bands used as weights (weighted mean). Only with respect to the Z (perpendicular) axis of the MMG signal, the stimulus frequency of 20 Hz did not exhibit any difference with the weighted mean (P = 0.666). For the frequencies of 20 and 25 Hz, the MMG signal displayed the bands between 12 and 16 Hz in the three axes (P frequencies from 30 to 100 Hz, the muscle presented a higher concentration of the MMG signal between the 22 and 29 Hz bands for the X and Z axes, and between 16 and 34 Hz bands for the Y axis (P frequency, because their frequency contents tend to mainly remain between the 20- and 25-Hz bands. Hence, NMES does not interfere with the use of MMG in neuroprosthesis. © 2018 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  2. Distance exercised during submaximal training on race winnings for Thoroughbred racehorses

    Directory of Open Access Journals (Sweden)

    Carolina Berkman

    2015-07-01

    Full Text Available Evaluations of the physical fitness of Thoroughbred racehorses have been correlated with race earnings, but few reports exist about the influence of the distance exercised during training on both physical conditioning indices and financial productivity. During one training season sixteen claiming Thoroughbred horses were subjected to submaximal training and monitored by a global positioning system (GPS coupled to a heart rate monitor. After initial and single monitoring, the horses were distributed into two groups of eight individuals each; one group exercised short distances (SD between 1600 and 1900m, while the other exercised long distances (LD between 2000 and 2350m. The duration (min and mean and maximal velocities (ms-1attained during each session were determined, as well as the difference in distances exercised (m between official races and each training session. Blood lactate concentration ([LA] during recovery was also determined. Student's t-test was used for a non-paired analysis, with P≤0.05 considered significant. The winnings (USD of each horse were correlated with the peak heart rate (HRpeak attained during the training session. The distances exercised in the training sessions were greater in relation to the official races distances by 24.7% and 40% for SD and LD, respectively. Lactatemia did not differ between the groups. The HRpeak obtained during the training session was lower in LD group. The velocity at which the heart rate reached 200 bpm (V200 was higher in LD group. There was a moderate correlation (r= 0.42 between the highest winnings and lowest HRpeak. The horses that ran longer distances during their submaximal training session had better cardiac conditioning and tendency to increase financial productivity

  3. The Effect of Submaximal Exercise Preceded by Single Whole-Body Cryotherapy on the Markers of Oxidative Stress and Inflammation in Blood of Volleyball Players

    Science.gov (United States)

    Mila-Kierzenkowska, Celestyna; Szpinda, Michał; Augustyńska, Beata; Woźniak, Bartosz

    2013-01-01

    The aim of the study was to determine the effect of single whole-body cryotherapy (WBC) session applied prior to submaximal exercise on the activity of antioxidant enzymes, the concentration of lipid peroxidation products, total oxidative status, and the level of cytokines in blood of volleyball players. The study group consisted of 18 male professional volleyball players, who were subjected to extremely cold air (−130°C) prior to exercise performed on cycloergometer. Blood samples were taken five times: before WBC, after WBC procedure, after exercise preceded by cryotherapy (WBC exercise), and before and after exercise without WBC (control exercise). The activity of catalase statistically significantly increased after control exercise. Moreover, the activity of catalase and superoxide dismutase was lower after WBC exercise than after control exercise (P < 0.001). After WBC exercise, the level of IL-6 and IL-1β was also lower (P < 0.001) than after control exercise. The obtained results may suggest that cryotherapy prior to exercise may have some antioxidant and anti-inflammatory properties. The relations between the level of studied oxidative stress and inflammatory markers may testify to the contribution of reactive oxygen species in cytokines release into the blood system in response to exercise and WBC. PMID:24489985

  4. The effect of submaximal exercise preceded by single whole-body cryotherapy on the markers of oxidative stress and inflammation in blood of volleyball players.

    Science.gov (United States)

    Mila-Kierzenkowska, Celestyna; Jurecka, Alicja; Woźniak, Alina; Szpinda, Michał; Augustyńska, Beata; Woźniak, Bartosz

    2013-01-01

    The aim of the study was to determine the effect of single whole-body cryotherapy (WBC) session applied prior to submaximal exercise on the activity of antioxidant enzymes, the concentration of lipid peroxidation products, total oxidative status, and the level of cytokines in blood of volleyball players. The study group consisted of 18 male professional volleyball players, who were subjected to extremely cold air (-130°C) prior to exercise performed on cycloergometer. Blood samples were taken five times: before WBC, after WBC procedure, after exercise preceded by cryotherapy (WBC exercise), and before and after exercise without WBC (control exercise). The activity of catalase statistically significantly increased after control exercise. Moreover, the activity of catalase and superoxide dismutase was lower after WBC exercise than after control exercise (P exercise, the level of IL-6 and IL-1β was also lower (P exercise. The obtained results may suggest that cryotherapy prior to exercise may have some antioxidant and anti-inflammatory properties. The relations between the level of studied oxidative stress and inflammatory markers may testify to the contribution of reactive oxygen species in cytokines release into the blood system in response to exercise and WBC.

  5. The Effect of Submaximal Exercise Preceded by Single Whole-Body Cryotherapy on the Markers of Oxidative Stress and Inflammation in Blood of Volleyball Players

    Directory of Open Access Journals (Sweden)

    Celestyna Mila-Kierzenkowska

    2013-01-01

    Full Text Available The aim of the study was to determine the effect of single whole-body cryotherapy (WBC session applied prior to submaximal exercise on the activity of antioxidant enzymes, the concentration of lipid peroxidation products, total oxidative status, and the level of cytokines in blood of volleyball players. The study group consisted of 18 male professional volleyball players, who were subjected to extremely cold air (−130∘C prior to exercise performed on cycloergometer. Blood samples were taken five times: before WBC, after WBC procedure, after exercise preceded by cryotherapy (WBC exercise, and before and after exercise without WBC (control exercise. The activity of catalase statistically significantly increased after control exercise. Moreover, the activity of catalase and superoxide dismutase was lower after WBC exercise than after control exercise (P<0.001. After WBC exercise, the level of IL-6 and IL-1β was also lower (P<0.001 than after control exercise. The obtained results may suggest that cryotherapy prior to exercise may have some antioxidant and anti-inflammatory properties. The relations between the level of studied oxidative stress and inflammatory markers may testify to the contribution of reactive oxygen species in cytokines release into the blood system in response to exercise and WBC.

  6. Effects of daily activity recorded by pedometer on peak oxygen consumption (VO2peak), ventilatory threshold and leg extension power in 30- to 69-year-old Japanese without exercise habit.

    Science.gov (United States)

    Zhang, Jian-Guo; Ohta, Toshiki; Ishikawa-Takata, Kazuko; Tabata, Izumi; Miyashita, Mitsumasa

    2003-09-01

    The relationships among walk steps, exercise habits and peak oxygen consumption (VO2peak), ventilatory threshold (VT) and leg extension power (LEP) were examined in 709 apparently healthy Japanese subjects (male 372, female 337) aged 30-69 years. Walk steps were evaluated using a pedometer. VO2peak and VT were assessed by a cycle ergometer test, while LEP was measured with an isokinetic leg extension system (Combi, Anaero Press 3500, Japan). Subjects who participated in exercise three times or more a week demonstrated significantly greater VO2peak and VT when compared with subjects without exercise habits. When a separate analysis was conducted on subjects who exercised fewer than three times per week, we found that the subgroup with the highest number of walk steps showed significantly greater VT in all male subjects and female subjects aged 30-49 years, but a significantly greater VO2peak only in females aged 30-49 years, when compared to the subgroup with the fewest walk steps. These results suggest that although some people exercise less than three times a week, if they are quite active in daily life, such activities might also confer benefits upon their fitness.

  7. Several submaximal exercise tests are reliable, valid and acceptable in people with chronic pain, fibromyalgia or chronic fatigue: a systematic review

    Directory of Open Access Journals (Sweden)

    Julia Ratter

    2014-09-01

    [Ratter J, Radlinger L, Lucas C (2014 Several submaximal exercise tests are reliable, valid and acceptable in people with chronic pain, fibromyalgia or chronic fatigue: a systematic review. Journal of Physiotherapy 60: 144–150

  8. Dose-response effect of photobiomodulation therapy on neuromuscular economy during submaximal running.

    Science.gov (United States)

    Dellagrana, Rodolfo André; Rossato, Mateus; Sakugawa, Raphael Luiz; Lazzari, Caetano Decian; Baroni, Bruno Manfredini; Diefenthaeler, Fernando

    2018-02-01

    The purpose of this study was to verify the photobiomodulation therapy (PBMT) effects with different doses on neuromuscular economy during submaximal running tests. Eighteen male recreational runners participate in a randomized, double-blind, and placebo-controlled trial, which each participant was submitted to the same testing protocol in five conditions: control, placebo, and PBMT with doses of 15, 30, and 60 J per site (14 sites in each lower limb). The submaximal running was performed at 8 and 9 km h -1 during 5 min for each velocity. Muscle activation of the vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), biceps femoris (BF), and gastrocnemius lateralis (GL) was collected during the last minute of each running test. The root mean square (RMS) was normalized by maximal isometric voluntary contraction (MIVC) performed a priori in an isokinetic dynamometer. The RMS sum of all muscles (RMS LEG ) was considered as main neuromuscular economy parameter. PBMT with doses of 15, 30, and 60 J per site [33 diodes = 5 lasers (850 nm), 12 LEDs (670 nm), 8 LEDs (880 nm), and 8 LEDs (950 nm)] or placebo applications occurred before running tests. For the statistical analysis, the effect size was calculated. Moreover, a qualitative inference was used to determine the magnitude of differences between groups. Peak torque and RMS during MIVCs showed small effect sizes. According to magnitude-based inference, PBMT with dose of 15 J per site showed possibly and likely beneficial effects on neuromuscular economy during running at 8 and 9 km h -1 , respectively. On other hand, PBMT with doses of 30 and 60 J per site showed possible beneficial effects only during running at 9 km h -1 . We concluded that PBMT improve neuromuscular economy and the best PBMT dose was 15 J per site (total dose of 420 J).

  9. Effect of gamma radiation on the concentration of pyruvate and lactate in erythrocytes of healthy men after submaximal physical exercise

    International Nuclear Information System (INIS)

    Zagorski, T.; Dudek, I.; Berkan, L.; Chmielewski, H.; Kedziora, J.

    1993-01-01

    The aim of this work was to study the effect of gamma radiation and submaximal physical exercise on the concentration of final products of anaerobic glycolytic pathway in erythrocytes of healthy men. Twenty one men aged 20-22 were examined. They underwent physical exercise at doses of 2 w/kg body weight for 15 min. Erythrocytes were taken in the rest and after physical exercise and were exposed to gamma radiation (500 Gy doses) from 60 Co source. The concentration of pyruvate was estimated by Fermognost tests and the concentration of lactate by Boehringer Mannheim tests. The submaximal physical exercise was found to cause a significantly increased concentration of pyruvate and lactate in the non-radiated and irradiated erythrocytes. Gamma radiation at 500 Gy dose was found to increase concentration of pyruvate in erythrocytes (in the rest and after physical exercise) with simultaneous decrease of lactate concentration. (author). 17 refs, 1 tab

  10. The repeated bout effect of typical lower body strength training sessions on sub-maximal running performance and hormonal response.

    Science.gov (United States)

    Doma, Kenji; Schumann, Moritz; Sinclair, Wade H; Leicht, Anthony S; Deakin, Glen B; Häkkinen, Keijo

    2015-08-01

    This study examined the effects of two typical strength training sessions performed 1 week apart (i.e. repeated bout effect) on sub-maximal running performance and hormonal. Fourteen resistance-untrained men (age 24.0 ± 3.9 years; height 1.83 ± 0.11 m; body mass 77.4 ± 14.0 kg; VOpeak 48.1 ± 6.1 M kg(-1) min(-1)) undertook two bouts of high-intensity strength training sessions (i.e. six-repetition maximum). Creatine kinase (CK), delayed-onset muscle soreness (DOMS), counter-movement jump (CMJ) as well as concentrations of serum testosterone, cortisol and testosterone/cortisol ratio (T/C) were examined prior to and immediately post, 24 (T24) and 48 (T48) h post each strength training bout. Sub-maximal running performance was also conducted at T24 and T48 of each bout. When measures were compared between bouts at T48, the degree of elevation in CK (-58.4 ± 55.6 %) and DOMS (-31.43 ± 42.9 %) and acute reduction in CMJ measures (4.1 ± 5.4 %) were attenuated (p 0.05). Sub-maximal running performance was impaired until T24, although changes were not attenuated following the second bout. The initial bout appeared to provide protection against a number of muscle damage indicators suggesting a greater need for recovery following the initial session of typical lower body resistance exercises in resistance-untrained men although sub-maximal running should be avoided following the first two sessions.

  11. Fatigue reduces the complexity of knee extensor torque fluctuations during maximal and submaximal intermittent isometric contractions in man

    Science.gov (United States)

    Pethick, Jamie; Winter, Samantha L; Burnley, Mark

    2015-01-01

    Neuromuscular fatigue increases the amplitude of fluctuations in torque output during isometric contractions, but the effect of fatigue on the temporal structure, or complexity, of these fluctuations is not known. We hypothesised that fatigue would result in a loss of temporal complexity and a change in fractal scaling of the torque signal during isometric knee extensor exercise. Eleven healthy participants performed a maximal test (5 min of intermittent maximal voluntary contractions, MVCs), and a submaximal test (contractions at a target of 40% MVC performed until task failure), each with a 60% duty factor (6 s contraction, 4 s rest). Torque and surface EMG signals were sampled continuously. Complexity and fractal scaling of torque were quantified by calculating approximate entropy (ApEn), sample entropy (SampEn) and the detrended fluctuation analysis (DFA) scaling exponent α. Fresh submaximal contractions were more complex than maximal contractions (mean ± SEM, submaximal vs. maximal: ApEn 0.65 ± 0.09 vs. 0.15 ± 0.02; SampEn 0.62 ± 0.09 vs. 0.14 ± 0.02; DFA α 1.35 ± 0.04 vs. 1.55 ± 0.03; all P torque, fatigue reduces the neuromuscular system's adaptability to external perturbations. PMID:25664928

  12. Influence of fatigue, stress, muscle soreness and sleep on perceived exertion during submaximal effort.

    Science.gov (United States)

    Haddad, Monoem; Chaouachi, Anis; Wong, Del P; Castagna, Carlo; Hambli, Mourad; Hue, Olivier; Chamari, Karim

    2013-07-02

    The aim of this study was to assess the effects of the Hooper's Index variations (i.e., self-ratings of fatigue, stress, delayed onset muscle soreness (DOMS), and sleep) on rating of perceived exertion during a 10 min submaximal exercise training session (RPE-10 min) and then check the stability and the internal consistency of RPE-10 min. Seventeen junior soccer players took part in this study. The individual Hooper's indices taken before each training session were correlated with RPE-10 min during a constant intensity and duration effort (10 min) using Pearson product moment correlation. Intraclass correlation (ICC) was used to assess the internal consistency of the RPE-10 min. All individual correlations between RPE-10 min and quality of sleep and quantity of fatigue, stress, and DOMS were non-significant (p>0.05). No significant correlations were resulted between RPE-10 min and Hooper's Index in all athletes. The ICC of RPE-10 min was 0.77 thus demonstrating internal consistency. The results of the present study demonstrated the objectivity and utility of RPE as a psychological tool for monitoring training during traditional soccer training. Therefore, the results of the present study suggest that fatigue, stress, DOMS and sleep are not major contributors of perceived exertion during traditional soccer training without excessive training loads. It seems that psychobiological factors other than fatigue, stress, DOMS and sleep may have mediated the 10 min exercise perceptual intensity. © 2013.

  13. Altitude acclimatization improves submaximal cognitive performance in mice and involves an imbalance of the cholinergic system.

    Science.gov (United States)

    Guerra-Narbona, R; Delgado-García, J M; López-Ramos, J C

    2013-06-15

    The aim of this work was to reveal a hypothetical improvement of cognitive abilities in animals acclimatized to altitude and performing under ground level conditions, when looking at submaximal performance, once seen that it was not possible when looking at maximal scores. We modified contrasted cognitive tasks (object recognition, operant conditioning, eight-arm radial maze, and classical conditioning of the eyeblink reflex), increasing their complexity in an attempt to find performance differences in acclimatized animals vs. untrained controls. In addition, we studied, through immunohistochemical quantification, the expression of choline acetyltransferase and acetyl cholinesterase, enzymes involved in the synthesis and degradation of acetylcholine, in the septal area, piriform and visual cortexes, and the hippocampal CA1 area of animals submitted to acute hypobaric hypoxia, or acclimatized to this simulated altitude, to find a relationship between the cholinergic system and a cognitive improvement due to altitude acclimatization. Results showed subtle improvements of the cognitive capabilities of acclimatized animals in all of the tasks when performed under ground-level conditions (although not before 24 h), in the three tasks used to test explicit memory (object recognition, operant conditioning in the Skinner box, and eight-arm radial maze) and (from the first conditioning session) in the classical conditioning task used to evaluate implicit memory. An imbalance of choline acetyltransferase/acetyl cholinesterase expression was found in acclimatized animals, mainly 24 h after the acclimatization period. In conclusion, altitude acclimatization improves cognitive capabilities, in a process parallel to an imbalance of the cholinergic system.

  14. Can the Lamberts and Lambert Submaximal Cycle Test Reflect Overreaching in Professional Cyclists?

    Science.gov (United States)

    Decroix, Lieselot; Lamberts, Robert P; Meeusen, Romain

    2018-01-01

    The Lamberts and Lambert Submaximal Cycle Test (LSCT) consists of 3 stages during which cyclists cycle for 6 min at 60%, 6 min at 80%, and 3 min at 90% of their maximal heart rate, followed by 1-min recovery. To determine if the LSCT is able to reflect a state of functional overreaching in professional female cyclists during an 8-d training camp and the following recovery days. Six professional female cyclists performed an LSCT on days 1, 5, and 8 of the training camp and 3 d after the training camp. During each stage of the LSCT, power output and rating of perceived exertion (RPE) were determined. Training diaries and Profile of Mood States (POMS) were also completed. At the middle and the end of the training camp, increased power output during the 2nd and 3rd stages of the LSCT was accompanied with increased RPE during these stages and/or the inability to reach 90% of maximal heart rate. All athletes reported increased feelings of fatigue and muscle soreness, while changes in energy balance, calculated from the POMS, were less indicative of a state of overreaching. After 3 d of recovery, all parameters of the LSCT returned to baseline, indicating a state of functional overreaching during the training camp. The LSCT is able to reflect a state of overreaching in elite professional female cyclists during an 8-d training camp and the following recovery days.

  15. Relationship between the Pedaling Biomechanics and Strain of Bicycle Frame during Submaximal Tests

    Directory of Open Access Journals (Sweden)

    Aneliya V. Manolova

    2015-06-01

    Full Text Available The aim of this study was to analyse the effect of forces applied to pedals and cranks on the strain imposed to an instrumented bicycle motocross (BMX frame. Using results from a finite element analysis to determine the localisation of highest stress, eight strain gauges were located on the down tube, the seat tube and the right chain stay. Before the pedaling tests, static loads were applied to the frame during bench tests. Two pedaling conditions have been analysed. In the first, the rider was in static standing position on the pedals and applied maximal muscular isometric force to the right pedal. The second pedaling condition corresponds to three pedaling sprint tests at submaximal intensities at 150, 300 and 550 W on a cycle-trainer. The results showed that smaller strain was observed in the pedaling condition than in the rider static standing position condition. The highest strains were located in the seat tube and the right chain stay near the bottom bracket area. The maximum stress observed through all conditions was 41 MPa on the right chain stay. This stress was 11 times lower than the yield stress of the frame material (460 MPa. This protocol could help to adapt the frame design to the riders as a function of their force and mechanical power output. These results could also help design BMX frames for specific populations (females and rider morphology.

  16. Effects of Submaximal Endurance Training and Vitamin D3 Supplementation on Pain Threshold in Diabetic Rats

    Directory of Open Access Journals (Sweden)

    S. Jalal Taherabadi

    2013-07-01

    Full Text Available Background: According to beneficial effects of endurance training and vitamin D3 in diabetes mellitus, purpose of this study is effects submaximal endurance training and vitamin D3 supplementation on pain threshold in streptozotocin induced diabetic rats.Materials and Methods: Male Wistar rats (250±20 g, N=40 were made diabetic by streptozotocin (60 mg/kg, subcutaneously. 72 h after injection diabetes induction was confirmed by tail vein blood glucose concentration (>300 mg/dl. Then animals were divided to five groups: diabetic control (DC, diabetic trained (DT, diabetic -vitamin D (DD, diabetic trained and vitamin D (DTD, and control (C. Animals were submitted to endurance training by treadmill and vitamin D3 treatment (twice aweek, intrapretonally for 4 weeks. 48 h after at the end of exercise and treatment protocol, we used tail-flick to assess the effects of training and vitamin D3 on thermal pain threshold. We used one way ANOVA statistical analysis to compare differences between groups, significance level of p<0.05 was considered.Results: Diabetic induced hyperalgesia were decreased significantly by vitamin D but not 4 weeks endurance exercise training. Concurrent effects of training and vitamin D on thermal pain threshold were not significantly higher than vitamin D effects alone.Conclusion: It is concluded that vitamin D administration given at the time of diabetes induction may be able to restore thermal hyperalgesia. But effects of endurance exercise training needs to more investigation in diabetic rats.

  17. Pedaling rate is an important determinant of human oxygen uptake during exercise on the cycle ergometer.

    Science.gov (United States)

    Formenti, Federico; Minetti, Alberto E; Borrani, Fabio

    2015-09-01

    Estimation of human oxygen uptake (V˙o2) during exercise is often used as an alternative when its direct measurement is not feasible. The American College of Sports Medicine (ACSM) suggests estimating human V˙o2 during exercise on a cycle ergometer through an equation that considers individual's body mass and external work rate, but not pedaling rate (PR). We hypothesized that including PR in the ACSM equation would improve its V˙o2 prediction accuracy. Ten healthy male participants' (age 19-48 years) were recruited and their steady-state V˙o2 was recorded on a cycle ergometer for 16 combinations of external work rates (0, 50, 100, and 150 W) and PR (50, 70, 90, and 110 revolutions per minute). V˙o2 was calculated by means of a new equation, and by the ACSM equation for comparison. Kinematic data were collected by means of an infrared 3-D motion analysis system in order to explore the mechanical determinants of V˙o2. Including PR in the ACSM equation improved the accuracy for prediction of sub-maximal V˙o2 during exercise (mean bias 1.9 vs. 3.3 mL O2 kg(-1) min(-1)) but it did not affect the accuracy for prediction of maximal V˙o2 (P > 0.05). Confirming the validity of this new equation, the results were replicated for data reported in the literature in 51 participants. We conclude that PR is an important determinant of human V˙o2 during cycling exercise, and it should be considered when predicting oxygen consumption. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  18. Mitochondrial Respiration and Oxygen Tension.

    Science.gov (United States)

    Shaw, Daniel S; Meitha, Karlia; Considine, Michael J; Foyer, Christine H

    2017-01-01

    Measurements of respiration and oxygen tension in plant organs allow a precise understanding of mitochondrial capacity and function within the context of cellular oxygen metabolism. Here we describe methods that can be routinely used for the isolation of intact mitochondria, and the determination of respiratory electron transport, together with techniques for in vivo determination of oxygen tension and measurement of respiration by both CO 2 production and O 2 consumption that enables calculation of the respiratory quotient [CO 2 ]/[O 2 ].

  19. Sustainable Consumption

    DEFF Research Database (Denmark)

    Røpke, Inge

    2015-01-01

    The intention of this chapter is to explore the role of consumption and consumers in relation to sustainability transition processes and wider systemic transformations. In contrast to the individualistic focus in much research on sustainable consumption, the embeddedness of consumption activities...... in wider social, economic and technological frameworks is emphasised. In particular, the chapter is inspired by practice theory and transition theory. First, various trends in consumption are outlined to highlight some of the challenges for sustainability transitions. Then, it is discussed how consumption...... patterns are shaped over time and what should be considered in sustainability strategies. While discussions on consumption often take their point of departure in the perspective of the individual and then zoom to the wider context, the present approach is the opposite. The outline starts with the basic...

  20. Effect of Caloric Restriction or Aerobic Exercise Training on Peak Oxygen Consumption and Quality of Life in Obese Older Patients with Heart Failure and Preserved Ejection Fraction A Randomized, Controlled Trial

    Science.gov (United States)

    Kitzman, Dalane W.; Brubaker, Peter; Morgan, Timothy; Haykowsky, Mark; Hundley, Gregory; Kraus, William E.; Eggebeen, Joel; Nicklas, Barbara J.

    2016-01-01

    Importance More than 80% of patients with heart failure with preserved ejection fraction (HFPEF), the most common form of HF among older persons, are overweight/obese. Exercise intolerance is the primary symptom of chronic HFPEF and a major determinant of reduced quality-of-life (QOL). Objective To determine whether caloric restriction (Diet), or aerobic exercise training (Exercise), improves exercise capacity and QOL in obese older HFPEF patients. Design Randomized, attention-controlled, 2x2 factorial trial conducted from February 2009 November 2014. Setting Urban academic medical center. Participants 100 older (67±5 years) obese (BMI=39.3±5.6kg/m2) women (n=81) and men (n=19) with chronic, stable HFPEF enrolled from 577 patients initially screened (366 excluded by inclusion / exclusion criteria, 31 for other reasons, 80 declined participation). Twenty-six participants were randomized to Exercise alone, 24 to Diet alone, 25 to Diet+Exercise, and 25 to Control; 92 completed the trial. Interventions 20 weeks of Diet and/or Exercise; Attention Control consisted of telephone calls every 2 weeks. Main Outcomes and Measures Exercise capacity measured as peak oxygen consumption (VO2, ml/kg/min; primary outcome) and QOL measured by the Minnesota Living with HF Questionnaire (MLHF) total score (co-primary outcome; score range: 0–105, higher scores indicate worse HF-related QOL). Results By main effects analysis, peak VO2 was increased significantly by both interventions: Exercise main effect 1.2 ml/kg/min (95%CI: 0.7,1.7; pDiet main effect 1.3 ml/kg/min (95%CI: 0.8,1.8; pExercise+Diet was additive (complementary) for peak VO2 (joint effect 2.5 ml/kg/min). The change in MLHF total score was non-significant with Exercise (main effect −1 unit; 95%CI: −8,5; p=0.70) and with Diet (main effect −6 units; 95%CI: −12,1; p=0.078). The change in peak VO2 was positively correlated with the change in percent lean body mass (r=0.32; p=0.003) and the change in thigh muscle

  1. Oxygen toxicity

    Directory of Open Access Journals (Sweden)

    C. A. van der Westhuizen

    1990-07-01

    Full Text Available Oxygen has been discovered about 200 years ago. Since then the vital physiological involvement of oxygen in various biologi­cal processes, mainly energy production, has been established. However, in the body molecular oxygen can be converted to toxic oxygen metabolites such as superoxide anion, hydrogen peroxide, the hydroxyl radical and singlet oxygen. These toxic metabolites are produced mainly in the mitochondria, plasma membranes and endoplasmic reticulum.

  2. Optic nerve oxygenation

    DEFF Research Database (Denmark)

    Stefánsson, Einar; Pedersen, Daniella Bach; Jensen, Peter Koch

    2005-01-01

    The oxygen tension of the optic nerve is regulated by the intraocular pressure and systemic blood pressure, the resistance in the blood vessels and oxygen consumption of the tissue. The oxygen tension is autoregulated and moderate changes in intraocular pressure or blood pressure do not affect...... the optic nerve oxygen tension. If the intraocular pressure is increased above 40 mmHg or the ocular perfusion pressure decreased below 50 mmHg the autoregulation is overwhelmed and the optic nerve becomes hypoxic. A disturbance in oxidative metabolism in the cytochromes of the optic nerve can be seen...... at similar levels of perfusion pressure. The levels of perfusion pressure that lead to optic nerve hypoxia in the laboratory correspond remarkably well to the levels that increase the risk of glaucomatous optic nerve atrophy in human glaucoma patients. The risk for progressive optic nerve atrophy in human...

  3. Acute Warm-up Effects in Submaximal Athletes: An EMG Study of Skilled Violinists.

    Science.gov (United States)

    McCrary, J Matt; Halaki, Mark; Sorkin, Evgeny; Ackermann, Bronwen J

    2016-02-01

    Warm-up is commonly recommended for injury prevention and performance enhancement across all activities, yet this recommendation is not supported by evidence for repetitive submaximal activities such as instrumental music performance. The objective of this study is to quantify the effects of cardiovascular, core muscle, and musical warm-ups on muscle activity levels, musical performance, and subjective experience in skilled violinists. Fifty-five undergraduate, postgraduate, or professional violinists performed five randomly ordered 45-s musical excerpts of varying physical demands both before and after a randomly assigned 15-min, moderate-intensity cardiovascular, core muscle, musical (technical violin exercises), or inactive control warm-up protocol. Surface EMG data were obtained for 16 muscles of the trunk, shoulders, and right arm during each musical performance. Sound recording and perceived exertion (RPE) data were also obtained. Sound recordings were randomly ordered and rated for performance quality by blinded adjudicators. Questionnaire data regarding participant pain sites and fitness levels were used to stratify participants according to pain and fitness levels. Data were analyzed using two- and three-factor ANCOVA (surface EMG and sound recording) and Wilcoxon matched pairs tests (RPE). None of the three warm-up protocols had significant effects on muscle activity levels (P ≥ 0.10). Performance quality did not significantly increase (P ≥ 0.21). RPE significantly decreased (P warm-up for each of the three experimental warm-ups; control condition RPE did not significantly decrease (P > 0.23). Acute physiological and musical benefits from cardiovascular, core muscle, and musical warm-ups in skilled violinists are limited to decreases in RPE. This investigation provides data from the performing arts in support of sports medical evidence suggesting that warm-up only effectively enhances maximal strength and power performance.

  4. A theoretical model for oxygen transport in skeletal muscle under conditions of high oxygen demand.

    Science.gov (United States)

    McGuire, B J; Secomb, T W

    2001-11-01

    Oxygen transport from capillaries to exercising skeletal muscle is studied by use of a Krogh-type cylinder model. The goal is to predict oxygen consumption under conditions of high demand, on the basis of a consideration of transport processes occurring at the microvascular level. Effects of the decline in oxygen content of blood flowing along capillaries, intravascular resistance to oxygen diffusion, and myoglobin-facilitated diffusion are included. Parameter values are based on human skeletal muscle. The dependence of oxygen consumption on oxygen demand, perfusion, and capillary density are examined. When demand is moderate, the tissue is well oxygenated and consumption is slightly less than demand. When demand is high, capillary oxygen content declines rapidly with axial distance and radial oxygen transport is limited by diffusion resistance within the capillary and the tissue. Under these conditions, much of the tissue is hypoxic, consumption is substantially less than demand, and consumption is strongly dependent on capillary density. Predicted consumption rates are comparable with experimentally observed maximal rates of oxygen consumption.

  5. Oxygen requirement of separated hybrid catfish eggs

    Science.gov (United States)

    Channel catfish egg masses require hatchery water with over 7.8 ppm dissolved oxygen at 80° F (95% air saturation) to maintain maximum oxygen consumption as they near hatching. This concentration is called the critical oxygen requirement by scientists but for the purpose of this article we will call...

  6. Assembling consumption

    DEFF Research Database (Denmark)

    Assembling Consumption marks a definitive step in the institutionalisation of qualitative business research. By gathering leading scholars and educators who study markets, marketing and consumption through the lenses of philosophy, sociology and anthropology, this book clarifies and applies...... the investigative tools offered by assemblage theory, actor-network theory and non-representational theory. Clear theoretical explanation and methodological innovation, alongside empirical applications of these emerging frameworks will offer readers new and refreshing perspectives on consumer culture and market...... societies. This is an essential reading for both seasoned scholars and advanced students of markets, economies and social forms of consumption....

  7. Near-infrared spectroscopy for monitoring muscle oxygenation

    DEFF Research Database (Denmark)

    Boushel, Robert Christopher; Piantadosi, C A

    2000-01-01

    Near-infrared spectroscopy (NIRS) is a non-invasive method for monitoring oxygen availability and utilization by the tissues. In intact skeletal muscle, NIRS allows semi-quantitative measurements of haemoglobin plus myoglobin oxygenation (tissue O2 stores) and the haemoglobin volume. Specialized...... algorithms allow assessment of the oxidation-reduction (redox) state of the copper moiety (CuA) of mitochondrial cytochrome c oxidase and, with the use of specific tracers, accurate assessment of regional blood flow. NIRS has demonstrated utility for monitoring changes in muscle oxygenation and blood flow...... during submaximal and maximal exercise and under pathophysiological conditions including cardiovascular disease and sepsis. During work, the extent to which skeletal muscles deoxygenate varies according to the type of muscle, type of exercise and blood flow response. In some instances, a strong...

  8. The effect of menstruation on chosen physiological and biochemical reactions caused by the physical effort with the submaximal intensity

    Directory of Open Access Journals (Sweden)

    P Zieliński

    2003-03-01

    Full Text Available The aim of this work was to determine the influence of the menstruation phase on changes of respective indicators of the gas exchange and on biochemical parameters of blood during physical efforts with the sub-maximal intensity. Fifteen female students of the Academy of Physical Education took part in the study. Girls were aged from 19 to 22 years old and did not practice sports. The effort tests were conducted in the follicular and luteal phase of two succeeding menstrual cycles. As far the aerobic capacity determination is concerned, one cyclo-ergometric test with graded effort was conducted and it was performed till the “refusal”. It allowed to mark a threshold (TDMA and a maximal level of physiological and biochemical indicators. Basing on the results of the graded test individual loads were determined for every next effort trial (repeated 4 times in every phase of the two succeeding menstrual cycles. The aim of this trial was to evaluate the reaction of women’s constitution on work with the sub-maximal intensity. The above trial consisted on two 10 min efforts divided with the 2 min pause (the first effort with the intensity of 80% of the TDMA threshold, second with the intensity bigger about 30-40% of difference between TDMA and a maximal load established by the graded test. The research did not reveal statistically significant differentiation as considering effort changes of basic physiological and biochemical indicators, determining reaction of women’s organisms on work with the sub- and over- threshold intensity (TDMA. It showed that menstruation has not significant effect on the level of changes of analysed parameters caused by the physical effort with the sub-maximal intensity.

  9. Reliability and Validity of a Submaximal Warm-up Test for Monitoring Training Status in Professional Soccer Players.

    Science.gov (United States)

    Rabbani, Alireza; Kargarfard, Mehdi; Twist, Craig

    2018-02-01

    Rabbani, A, Kargarfard, M, and Twist, C. Reliability and validity of a submaximal warm-up test for monitoring training status in professional soccer players. J Strength Cond Res 32(2): 326-333, 2018-Two studies were conducted to assess the reliability and validity of a submaximal warm-up test (SWT) in professional soccer players. For the reliability study, 12 male players performed an SWT over 3 trials, with 1 week between trials. For the validity study, 14 players of the same team performed an SWT and a 30-15 intermittent fitness test (30-15IFT) 7 days apart. Week-to-week reliability in selected heart rate (HR) responses (exercise heart rate [HRex], heart rate recovery [HRR] expressed as the number of beats recovered within 1 minute [HRR60s], and HRR expressed as the mean HR during 1 minute [HRpost1]) was determined using the intraclass correlation coefficient (ICC) and typical error of measurement expressed as coefficient of variation (CV). The relationships between HR measures derived from the SWT and the maximal speed reached at the 30-15IFT (VIFT) were used to assess validity. The range for ICC and CV values was 0.83-0.95 and 1.4-7.0% in all HR measures, respectively, with the HRex as the most reliable HR measure of the SWT. Inverse large (r = -0.50 and 90% confidence limits [CLs] [-0.78 to -0.06]) and very large (r = -0.76 and CL, -0.90 to -0.45) relationships were observed between HRex and HRpost1 with VIFT in relative (expressed as the % of maximal HR) measures, respectively. The SWT is a reliable and valid submaximal test to monitor high-intensity intermittent running fitness in professional soccer players. In addition, the test's short duration (5 minutes) and simplicity mean that it can be used regularly to assess training status in high-level soccer players.

  10. Aortopulmonary collateral flow quantification by MR at rest and during continuous submaximal exercise in patients with total cavopulmonary connection.

    Science.gov (United States)

    Mkrtchyan, Naira; Frank, Yvonne; Steinlechner, Eva; Calavrezos, Lenika; Meierhofer, Christian; Hager, Alfred; Martinoff, Stefan; Ewert, Peter; Stern, Heiko

    2017-11-06

    Aortopulmonary collateral flow is considered to have significant impact on the outcome of patients with single ventricle circulation and total cavopulmonary connection (TCPC). There is little information on collateral flow during exercise. To quantify aortopulmonary collateral flow at rest and during continuous submaximal exercise in clinical patients doing well with TCPC. Prospective, case controlled. Thirteen patients with TCPC (17 (11-37) years) and 13 age and sex-matched healthy controls (18 (11-38) years). 1.5T; free breathing; phase sensitive gradient echo sequence. Blood flow in the ascending and descending aorta and superior vena cava were measured at rest and during continuous submaximal physical exercise in patients and controls. Systemic blood flow (Q s ) was assumed to be represented by the sum of flow in the superior caval vein (Q svc ) and the descending aorta (Q AoD ) at the diaphragm level. Aortopulmonary collateral flow (Q coll ) was calculated by subtracting Q s from flow in the ascending aorta (Q AoA ). Mann-Whitney U-test and Wilcoxon test for comparison between groups and between rest and exercise. Absolute collateral flow in TCPC patients at rest was 0.4 l/min/m 2 (-0.1-1.2), corresponding to 14% (-2-42) of Q s . Collateral flow did not change during exercise (difference -0.01 (-0.7-1.0) l/min/m 2 , P = 0.97). TCPC patients had significantly lower Q s at rest (2.5 (1.6-4.1) vs. 3.5 (2.6-4.8) l/min/m 2 , P = 0.001) and during submaximal exercise (3.2 (2.0-6.0) vs. 4.8 (3.3-6.9) l/min/m 2 , P = 0.001), compared to healthy controls. The increase in Q s with exercise was also significantly lower in patients than in healthy controls (median 0.6 vs. 1.2 l/min/m 2 , P collateral flow at rest (14% of Q s ) compared to healthy controls, which does not change during submaximal exercise. 2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017. © 2017 International Society for Magnetic Resonance in Medicine.

  11. Oxygen Therapy

    Science.gov (United States)

    ... their breathing to dangerously low levels. Will I need oxygen when I sleep? Usually if you use supplemental oxygen during the ... your health care provider tells you you only need to use oxygen for exercise or sleep. Even if you feel “fine” off of your ...

  12. Myocardial perfusion after prolonged submaximal exercise in patients with coronary artery disease

    International Nuclear Information System (INIS)

    Flotats, A.; Mena, E.; Camacho, V.; Tembl, A.; Hernandez, M.A.; Estorch, M.; Carrio, I.; Serra-Grima, R.

    2002-01-01

    Aim: Exercise training in patients with coronary artery disease (CAD) has established benefits. We assessed myocardial perfusion after submaximal but prolonged exercise in patients with CAD, who were enrolled in supervised exercise rehabilitation programs. Material and Methods: Nine patients with CAD enrolled in supervised exercise rehabilitation programs (7 men, 2 women; mean age 54±9 years), 7 with prior AMI and 2 with re-vascularized (CABG) multiple vessel disease, were encouraged to walk/run actively around the perimeter of our Hospital during the annual social sporting event organised in our Institution. Patients were studied by means of perfusion Tc-99m tetrofosmin SPECT imaging after prolonged exercise and at rest (gated SPECT), for two consecutive years. All patients remained symptom free during this interval period. Quantitative analysis was performed dividing polar map images in 13 segments. Tracer activity 9% in the resting image. The analysis was focused on those segments showing perfusion defects. Results: No symptoms other than fatigue were registered during prolonged exercise (range 1-2 hr). There were no significant differences in distance covered (7,462±3,031 m vs. 8,456±2,998 m), heart rate (92±11 bpm vs. 85±13 bpm) and rate-pressure product at the end of exercise (10,804±2,467 vs. 10,403±2,955) or gated SPECT calculated LVEF (44%±19 vs. 46%±20) between the two consecutive annual sporting events. Tracer activity in segments with perfusion defects did not significantly differ between both events. Overall agreement between both examinations regarding patient classification as having scar/ischemia was 77% (kappa=0.49). There was one patient who showed partial reversibility in three segments, consistent with mild anteroapical ischemia, only in the first examination. On the other hand, another patient showed reversibility in one segment (medium septum), only in the second examination, when he covered a distance 1.3 times superior. Conclusions

  13. Normobaric Hypoxia and Submaximal Exercise Effects on Running Memory and Mood State in Women.

    Science.gov (United States)

    Seo, Yongsuk; Gerhart, Hayden D; Stavres, Jon; Fennell, Curtis; Draper, Shane; Glickman, Ellen L

    2017-07-01

    An acute bout of exercise can improve cognitive function in normoxic and hypoxic conditions. However, limited research supports the improvement of cognitive function and mood state in women. The purpose of this study was to examine the effects of hypoxia and exercise on working memory and mood state in women. There were 15 healthy women (age = 22 ± 2 yr) who completed the Automated Neuropsychological Assessment Metrics-4th Edition (ANAM), including the Running Memory Continuous Performance Task (RMCPT) and Total Mood Disturbance (TMD) in normoxia (21% O2), at rest in normoxia and hypoxia (12.5% O2), and during cycling exercise at 60% and 40% Vo2max in hypoxia. RMCPT was not significantly impaired at 30 (100.3 ± 17.2) and 60 (96.6 ± 17.3) min rest in hypoxia compared to baseline in normoxia (97.0 ± 17.0). However, RMCPT was significantly improved during exercise (106.7 ± 20.8) at 60% Vo2max compared to 60 min rest in hypoxia. Following 30 (-89.4 ± 48.3) and 60 min of exposure to hypoxia (-79.8 ± 55.9) at rest, TMD was impaired compared with baseline (-107.1 ± 46.2). TMD was significantly improved during exercise (-108.5 ± 42.7) at 40% Vo2max compared with 30 min rest in hypoxia. Also, RMCPT was significantly improved during exercise (104.0 ± 19.1) at 60% Vo2max compared to 60 min rest in hypoxia (96.6 ± 17.3). Hypoxia and an acute bout of exercise partially influence RMCPT and TMD. Furthermore, a moderate-intensity bout of exercise (60%) may be a more potent stimulant for improving cognitive function than low-intensity (40%) exercise. The present data should be considered by aeromedical personnel performing cognitive tasks in hypoxia.Seo Y, Gerhart HD, Stavres J, Fennell C, Draper S, Glickman EL. Normobaric hypoxia and submaximal exercise effects on running memory and mood state in women. Aerosp Med Hum Perform. 2017; 88(7):627-632.

  14. Voluntary movement frequencies in submaximal one- and two-legged knee extension exercise and pedaling

    Directory of Open Access Journals (Sweden)

    Julie Sørbø Stang

    2016-02-01

    Full Text Available Understanding of behavior and control of human voluntary rhythmic stereotyped leg movements is useful in work to improve performance, function, and rehabilitation of exercising, healthy, and injured humans. The present study aimed at adding to the existing understanding within this field. To pursue the aim, correlations between freely chosen movement frequencies in relatively simple, single-joint, one- and two-legged knee extension exercise were investigated. The same was done for more complex, multiple-joint, one- and two-legged pedaling. These particular activities were chosen because they could be considered related to some extent, as they shared a key aspect of knee extension, and because they at the same time were different. The activities were performed at submaximal intensities, by healthy individuals (n=16, thereof 8 women; 23.4±2.7 years; 1.70±0.11 m; 68.6±11.2 kg.High and fair correlations (R-values of 0.99 and 0.75 occurred between frequencies generated with the dominant leg and the nondominant leg during knee extension exercise and pedaling, respectively. Fair to high correlations (R-values between 0.71 and 0.95 occurred between frequencies performed with each of the two legs in an activity, and the two-legged frequency performed in the same type of activity. In general, the correlations were higher for knee extension exercise than for pedaling. Correlations between knee extension and pedaling frequencies were of modest occurrence.The correlations between movement frequencies generated separately by each of the legs might be interpreted to support the following working hypothesis, which was based on existing literature. It is likely that involved central pattern generators (CPGs of the two legs share a common frequency generator or that separate frequency generators of each leg are attuned via interneuronal connections. Further, activity type appeared to be relevant. Thus, the apparent common rhythmogenesis for the two legs

  15. The effects of gamma radiation on 2,3-diphosphoglycerate (2,3-DFG) content in healthy men's erythrocytes after submaximal physical exercise

    International Nuclear Information System (INIS)

    Dudek, I.; Zagorski, T.; Kedziora, J.

    1987-01-01

    The effects of gamma radiation and submaximal physical exercise on 2,3-DFG content in healthy men erythrocytes were studied. Twelve men aged 20-22 were examined. They were loaded by physical exrecise (at doses of 2 M/kg body weight) for 15 minutes. Erythrocytes were exposed to gamma radiation (500 Gy doses) from a 60 Co source. The concentration of 2,3-DFG in erythrocytes was estimated by Bartlett's method. Gamma radiation was found to decrese 2,3-DFG content in erythrocytes both at rest and after submaximal exercise. Furthermore, submaximal physical exercise was found to decrease 2,3-DFG content in non-irradiated erythrocytes. 20 refs., 1 tab. (author)

  16. Oxygen Therapy

    Directory of Open Access Journals (Sweden)

    Bonnie Solmes

    2000-01-01

    Full Text Available LTOT is prescribed for people with chronic lung disease in whom there is a decrease in the ability of the lungs to supply enough oxygen to the body. The heart is obliged to pump faster to meet the body's oxygen requirements. This may place undue stress on the heart, resulting in palpitations, dizziness and fatigue. A low oxygen level in arterial blood is also harmful to the heart, the brain and the pulmonary blood vessels. Oxygen therapy is used to break this cycle. A person with low blood oxygen will often be able to accomplish more with less fatigue with the help of supplemental oxygen therapy. Shortness of breath is a mechanical problem resulting from the effects of chronic obstructive pulmonary disease. Oxygen therapy may or may not reduce shortness of breath, but it will help the lungs and heart to function with less stress.

  17. Collaborative Consumption

    DEFF Research Database (Denmark)

    Gjerdrum Pedersen, Esben Rahbek; Netter, Sarah

    2015-01-01

    Purpose – The purpose of this paper is to explore barriers and opportunities for business models based on the ideas of collaborative consumption within the fashion industry. Design/methodology/approach – The analysis is based on a multiple-case study of Scandinavian fashion libraries – a new...... to the new phenomenon of fashion libraries and does not cover other types of collaborative consumption within the fashion industry (Swap-parties, etc.). Originality/value – The paper is one of the first attempts to examine new business models of collaborative consumption in general and the fashion library...... concept in particular. The study contributes to the discussions of whether and how fashion sharing and collaboration holds promise as a viable business model and as a means to promote sustainability....

  18. Collaborative Consumption

    DEFF Research Database (Denmark)

    Gjerdrum Pedersen, Esben Rahbek; Netter, Sarah

    Purpose: The purpose of this paper is to explore barriers and opportunities for business models based on the ideas of collaborative consumption within the fashion industry. Design/methodology/approach: The analysis is based on a multiple-­‐‑case study of Scandinavian fashion libraries – a new...... to the new phenomenon of fashion libraries and does not cover other types of collaborative consumption within the fashion industry (Swap-­‐‑parties, etc.). Originality/value: The paper is one of the first attempts to examine new business models of collaborative consumption in general and the fashion library...... concept in particular. The study contributes to the discussions of whether and how fashion sharing and collaboration holds promise as a viable business model and as a means to promote sustainability....

  19. Positioning consumption

    DEFF Research Database (Denmark)

    Halkier, Bente; Keller, Margit

    2014-01-01

    positionings emerges based on empirical examples of research in parent–children consumption. Positionings are flexible discursive fixations of the relationship between the performances of the practitioner, other practitioners, media discourse and consumption activities. The basic positioning types...... are the practice maintenance and the practice change position, with different sorts of adapting in between. Media discourse can become a resource for a resistant position against social control or for an appropriating position in favour of space for action. Regardless of the current relation to a particular media......This article analyses the ways in which media discourses become a part of contested consumption activities. We apply a positioning perspective with practice theory to focus on how practitioners relate to media discourse as a symbolic resource in their everyday practices. A typology of performance...

  20. Comparison of myocardial 201Tl clearance after maximal and submaximal exercise: implications for diagnosis of coronary disease: concise communication

    International Nuclear Information System (INIS)

    Massie, B.M.; Wisneski, J.; Kramer, B.; Hollenberg, M.; Gertz, E.; Stern, D.

    1982-01-01

    Recently the quantitation of regional 201 Tl clearance has been shown to increase the sensitivity of the scintigraphic detection of coronary disease. Although 201 Tl clearance rates might be expected to vary with the degree of exercise, this relationship has not been explored. We therefore evaluated the rate of decrease in myocardial 201 Tl activity following maximal and submaximal stress in seven normal subjects and 21 patients with chest pain, using the seven-pinhole tomographic reconstruction technique. In normals, the mean 201 Tl clearance rate declined from 41% +/- 7 over a 3-hr period with maximal exercise to 25% +/- 5 after 3 hr at a submaximal level (p less than 0.001). Similar differences in clearance rates were found in the normally perfused regions of the left ventricle in patients with chest pain, depending on whether or not a maximal end point (defined as either the appearance of ischemia or reaching 85% of age-predicted heart rate) was achieved. In five patients who did not reach these end points, 3-hr clearance rates in uninvolved regions averaged 25% +/- 2, in contrast to a mean of 38% +/- 5 for such regions in 15 patients who exercised to ischemia or an adequate heart rate. These findings indicate that clearance criteria derived from normals can be applied to patients who are stressed maximally, even if the duration of exercise is limited, but that caution must be used in interpreting clearance rates in those who do not exercise to an accepted end point

  1. Lean consumption.

    Science.gov (United States)

    Womack, James P; Jones, Daniel T

    2005-03-01

    During the past 20 years, the real price of most consumer goods has fallen worldwide, the variety of goods and the range of sales channels offering them have continued to grow, and product quality has steadily improved. So why is consumption often so frustrating? It doesn't have to be--and shouldn't be--the authors say. They argue that it's time to apply lean thinking to the processes of consumption--to give consumers the full value they want from goods and services with the greatest efficiency and the least pain. Companies may think they save time and money by off-loading work to the consumer but, in fact, the opposite is true. By streamlining their systems for providing goods and services, and by making it easier for customers to buy and use those products and services, a growing number of companies are actually lowering costs while saving everyone time. In the process, these businesses are learning more about their customers, strengthening consumer loyalty, and attracting new customers who are defecting from less user-friendly competitors. The challenge lies with the retailers, service providers, manufacturers, and suppliers that are not used to looking at total cost from the standpoint of the consumer and even less accustomed to working with customers to optimize the consumption process. Lean consumption requires a fundamental shift in the way companies think about the relationship between provision and consumption, and the role their customers play in these processes. It also requires consumers to change the nature of their relationships with the companies they patronize. Lean production has clearly triumphed over similar obstacles in recent years to become the dominant global manufacturing model. Lean consumption, its logical companion, can't be far behind.

  2. The oxygen effect and cellular adaptation

    International Nuclear Information System (INIS)

    Meshcherikova, V.V.; Vajnson, A.A.; Yarmonenko, S.P.

    1979-01-01

    The radiomodifying effect of oxygen was shown to depend on the level of cellular oxygenation prior to irradiation. Acute hypoxia created at the time of irradiation protects previously normally oxygenated cells with DMF approximately 1.4 times larger than that of cells cultured for 24 hours under conditions of mild hypoxia. It is suggested that a decrease in the radioprotective effect of acute hypoxia on chronically hypoxic cells is correlated with an appreciable decrease in the rate of oxygen consumption by these cells, due to which the oxygen concentration near the intracellular targets in chronically hypoxic cells may be higher than in normal cells under conditions of poor oxygenation

  3. Intraportal islet oxygenation.

    Science.gov (United States)

    Suszynski, Thomas M; Avgoustiniatos, Efstathios S; Papas, Klearchos K

    2014-05-01

    Islet transplantation (IT) is a promising therapy for the treatment of diabetes. The large number of islets required to achieve insulin independence limit its cost-effectiveness and the number of patients who can be treated. It is believed that >50% of islets are lost in the immediate post-IT period. Poor oxygenation in the early post-IT period is recognized as a possible reason for islet loss and dysfunction but has not been extensively studied. Several key variables affect oxygenation in this setting, including (1) local oxygen partial pressure (pO(2)), (2) islet oxygen consumption, (3) islet size (diameter, D), and (4) presence or absence of thrombosis on the islet surface. We discuss implications of oxygen-limiting conditions on intraportal islet viability and function. Of the 4 key variables, the islet size appears to be the most important determinant of the anoxic and nonfunctional islet volume fractions. Similarly, the effect of thrombus formation on the islet surface may be substantial. At the University of Minnesota, average size distribution data from clinical alloislet preparations (n = 10) indicate that >150-µm D islets account for only ~30% of the total islet number, but >85% of the total islet volume. This suggests that improved oxygen supply to the islets may have a profound impact on islet survivability and function since most of the β-cell volume is within large islets which are most susceptible to oxygen-limiting conditions. The assumption that the liver is a suitable islet transplant site from the standpoint of oxygenation should be reconsidered. © 2014 Diabetes Technology Society.

  4. Unsustainable Consumption

    DEFF Research Database (Denmark)

    Thøgersen, John

    2014-01-01

    Our dominant way of living is not sustainable and our activities as private individuals and households directly and indirectly account for a large and increasing share of total environmental impacts. These impacts are related to the structure as well as the level of consumption. In this article, ...

  5. Consumption bomb.

    Science.gov (United States)

    Harrison, P

    1999-01-01

    This article focuses on the issue of consumption in relation to the growing world population. Over the past 25 years, world population increased by 53%, while world consumption per person increased by only 39%. If consumption continues to grow at 1.4%, the world consumption per person will rise by 100% over the next 50 years with the population increasing by only half that amount. The burden of reducing the environmental impact brought about by this increase lies on technology. Technology needs to deliver major changes in improving resource productivity, and decreasing the amount of waste created. Productivity such as global food production has kept up with demand. Malnutrition persists due to poverty, and not because of the inability of the world to produce enough food. However, the prospects are much worse for resources that are not traded on markets or subject to sustainable management such as groundwater, state forests, ocean fish, and communal waste sinks like rivers, lakes, and the global atmosphere. These resources are not under the direct control of people affected by shortage. People who want to change the way these resources are used or managed have to pass through the legal or political system. Usually, political responses are slow and there has to be a very widespread environmental damage before action is taken.

  6. Transdisciplinary Consumption

    Directory of Open Access Journals (Sweden)

    Sue L.T. McGregor

    2013-06-01

    Full Text Available For the past 100 years, research about consumption has stemmed from two main disciplines: (a consumer studies/consumer sciences (including consumer policy and education (a spin off from home economics and (b consumer behaviour research (a spin off from marketing. This paper focuses on these two disciplines because the results of their respective research are used to shape consumer policy and consumer protection legislation and regulations, marketplace competition policy and regulations, consumer product and service information, media coverage of consumer issues, consumer education curricula and pedagogy, and insights into an evolving consumer culture. This paper asks consumer studies/sciences and consumer behaviour scholars to embrace the transdisciplinary methodology in addition to the traditional empirical, interpretive and critical methodologies. It provides an overview of the four axioms of transdisciplinary methodology with examples to illustrate how consumer-related research would change to address the complex reality of 21st century consumption.

  7. Collaborative Consumption

    OpenAIRE

    Rahbek Gjerdrum Pedersen, Esben; Netter, Sarah

    2013-01-01

    Purpose: The purpose of this paper is to explore barriers and opportunities for business models based on the ideas of collaborative consumption within the fashion industry. Design/methodology/approach: The analysis is based on a multiple-­‐‑case study of Scandinavian fashion libraries – a new, clothes-­‐‑sharing concept that has emerged as a fashion niche within the last decade. Findings: It is concluded that fashion libraries offers interesting perspectives, e.g. by allow...

  8. Several submaximal exercise tests are reliable, valid and acceptable in people with chronic pain, fibromyalgia or chronic fatigue: a systematic review

    NARCIS (Netherlands)

    Ratter, Julia; Radlinger, Lorenz; Lucas, Cees

    2014-01-01

    Are submaximal and maximal exercise tests reliable, valid and acceptable in people with chronic pain, fibromyalgia and fatigue disorders? Systematic review of studies of the psychometric properties of exercise tests. People older than 18 years with chronic pain, fibromyalgia and chronic fatigue

  9. (-)-Epicatechin administration and exercising skeletal muscle vascular control and microvascular oxygenation in healthy rats.

    Science.gov (United States)

    Copp, Steven W; Inagaki, Tadakatsu; White, Michael J; Hirai, Daniel M; Ferguson, Scott K; Holdsworth, Clark T; Sims, Gabrielle E; Poole, David C; Musch, Timothy I

    2013-01-15

    Consumption of the dietary flavanol (-)-epicatechin (EPI) is associated with enhanced endothelial function and augmented skeletal muscle capillarity and mitochondrial volume density. The potential for EPI to improve peripheral vascular function and muscle oxygenation during exercise is unknown. We tested the hypothesis that EPI administration in healthy rats would improve treadmill exercise performance secondary to elevated skeletal muscle blood flow and vascular conductance [VC, blood flow/mean arterial pressure (MAP)] and improved skeletal muscle microvascular oxygenation. Rats received water (control, n = 12) or 4 mg/kg EPI (n = 12) via oral gavage daily for 24 days. Exercise endurance capacity and peak O(2) uptake (Vo(2) peak) were measured via treadmill runs to exhaustion. MAP (arterial catheter) and blood flow (radiolabeled microspheres) were measured and VC was calculated during submaximal treadmill exercise (25 m/min, 5% grade). Spinotrapezius muscle microvascular O(2) pressure (Po(2mv)) was measured (phosphorescence quenching) during electrically induced twitch (1 Hz) contractions. In conscious rats, EPI administration resulted in lower (↓~5%) resting (P = 0.03) and exercising (P = 0.04) MAP. There were no differences in exercise endurance capacity, Vo(2) peak, total exercising hindlimb blood flow (control, 154 ± 13; and EPI, 159 ± 8 ml·min(-1)·100 g(-1), P = 0.68), or VC (control, 1.13 ± 0.10; and EPI, 1.24 ± 0.08 ml·min(-1)·100 g(-1)·mmHg(-1), P = 0.21) between groups. Following anesthesia, EPI resulted in lower MAP (↓~16%) but did not impact resting Po(2mv) or any kinetics parameters (P > 0.05 for all) during muscle contractions compared with control. EPI administration (4 mg·kg(-1)·day(-1)) improved modestly cardiovascular function (i.e., ↓MAP) with no impact on exercise performance, total exercising skeletal muscle blood flow and VC, or contracting muscle microvascular oxygenation in healthy rats.

  10. Torque decrease during submaximal evoked contractions of the quadriceps muscle is linked not only to muscle fatigue.

    Science.gov (United States)

    Matkowski, Boris; Lepers, Romuald; Martin, Alain

    2015-05-01

    The aim of this study was to analyze the neuromuscular mechanisms involved in the torque decrease induced by submaximal electromyostimulation (EMS) of the quadriceps muscle. It was hypothesized that torque decrease after EMS would reflect the fatigability of the activated motor units (MUs), but also a reduction in the number of MUs recruited as a result of changes in axonal excitability threshold. Two experiments were performed on 20 men to analyze 1) the supramaximal twitch superimposed and evoked at rest during EMS (Experiment 1, n = 9) and 2) the twitch response and torque-frequency relation of the MUs activated by EMS (Experiment 2, n = 11). Torque loss was assessed by 15 EMS-evoked contractions (50 Hz; 6 s on/6 s off), elicited at a constant intensity that evoked 20% of the maximal voluntary contraction (MVC) torque. The same stimulation intensity delivered over the muscles was used to induce the torque-frequency relation and the single electrical pulse evoked after each EMS contraction (Experiment 2). In Experiment 1, supramaximal twitch was induced by femoral nerve stimulation. Torque decreased by ~60% during EMS-evoked contractions and by only ~18% during MVCs. This was accompanied by a rightward shift of the torque-frequency relation of MUs activated and an increase of the ratio between the superimposed and posttetanic maximal twitch evoked during EMS contraction. These findings suggest that the torque decrease observed during submaximal EMS-evoked contractions involved muscular mechanisms but also a reduction in the number of MUs recruited due to changes in axonal excitability. Copyright © 2015 the American Physiological Society.

  11. The effect of graduated compression tights, compared with running shorts, on counter movement jump performance before and after submaximal running.

    Science.gov (United States)

    Rugg, Stuart; Sternlicht, Eric

    2013-04-01

    The purpose of this study was to determine if wearing graduated compression tights, compared with loose fitting running shorts, would increase and or help sustain counter movement jump (CMJ) height after submaximal running. Fourteen competitive runners (6 women and 8 men) participated in this study. The subjects' mean (±SD) for age, height, body mass, percent body fat, resting heart rate, and maximal heart rate were 28.2 ± 14.0 years, 174.7 ± 8.6 cm, 70.2 ± 14.9 kg, 15.5 ± 8.1%, 67.2 ± 7.4 b.min, and 186.5 ± 9.5 b.min, respectively. During testing, subjects wore a Polar RS400 heart rate monitor. Each trial consisted of 15 minutes of continual treadmill running with 5 minutes performed at 50%, 70%, and 85% of the subject's heart rate reserve. Using a Vertec vertical leaper, each subject performed 3 CMJ, both pre- and postrun trials, with the mean value used to measure relative leg power. In addition to the CMJ height data, each subject rated their level of perceived exertion (RPE), and their comfort level, after the postrun trials. The mean postrun CMJ height in graduated compression tights of 60.3 ± 19.4 cm was significantly greater (at the p shorts of 57.7 ± 19.6 cm (4.5% increase). In addition, the subjects reported a significantly lower level of perceived exertion and greater comfort values while wearing the graduated compression tights. The results of the present study support the use of graduated compression tights for maintenance of lower limb muscle power after submaximal endurance running.

  12. Flexible Consumption

    DEFF Research Database (Denmark)

    Holm Jacobsen, Peter; Pallesen, Trine

    This report presents the first findings from our qualitative study of consumer behaviour vis-à-vis flexible consumption. The main of objective of this report is to present our first round of data from Bornholm, and to assist the design of products/services designed in WP6. In the report, we adopt...... the perspective of the consumer: what does living in a demand response setup look like to participants – and what kinds of behaviour and interest motivate – and emerge from – their participation in EcoGrid 2.0....

  13. The oxygen effect and adaptive response of cells. Report 3. Simulation of respiratory oxygenation and oxygen permeability of cells

    International Nuclear Information System (INIS)

    Ehpshtejn, I.M.

    1978-01-01

    Variations in the oxygen concentration in extracellural [O 2 ] 0 and intracellular [Osub(2)]sub(i) media of cells small in size (d = 2 ] 0 - t-curves). It is shown that the Value of [Osub(2)]sub(i) may be expressed by four variants of its functional dependence: (a) on enzymic reaction of oxygen consumption, (b) on the order of reaction with respect to oxygen, (c) on physiological parameters of cells, and (d) on characteristic oxygen concentrations in the system. Items (c) and (d) are based on the postulated diffusion-kinetic model of oxygen consumption by an idealized cell of small size that consists of a drop of homogenous solution of the respiratory enzyme which is characterized by an equivalent Michaelis constant. The drop is enveloped in a uniform membrane that possesses a definite diffuse resistance to oxygen

  14. Impaired Muscle Oxygenation and Elevated Exercise Blood Pressure in Hypertensive Patients: Links With Vascular Stiffness.

    Science.gov (United States)

    Dipla, Konstantina; Triantafyllou, Areti; Koletsos, Nikolaos; Papadopoulos, Stavros; Sachpekidis, Vasileios; Vrabas, Ioannis S; Gkaliagkousi, Eugenia; Zafeiridis, Andreas; Douma, Stella

    2017-08-01

    This study examined in vivo (1) skeletal muscle oxygenation and microvascular function, at rest and during handgrip exercise, and (2) their association with macrovascular function and exercise blood pressure (BP), in newly diagnosed, never-treated patients with hypertension and normotensive individuals. Ninety-one individuals (51 hypertensives and 40 normotensives) underwent office and 24-hour ambulatory BP, arterial stiffness, and central aortic BP assessment, followed by a 5-minute arterial occlusion and a 3-minute submaximal handgrip exercise. Changes in muscle oxygenated and deoxygenated hemoglobin and tissue oxygen saturation were continuously monitored by near-infrared spectroscopy and beat-by-beat BP by Finapres. Hypertensives had higher ( P age and body mass index (BMI) adjusted). When exercising at the same submaximal intensity, hypertensives required a significantly greater ( P hypertension exhibit prominent reductions in in vivo indices of skeletal muscle oxidative capacity, suggestive of mitochondrial dysfunction, and blunted muscle microvascular reactivity. These dysfunctions were associated with higher aortic systolic BP and arterial stiffness. Dysregulations in muscle oxygen delivery/utilization and microvascular stiffness, in hypertensive patients, partially contribute to their exaggerated BP during exercise. © 2017 American Heart Association, Inc.

  15. Effects of Hemopure on maximal oxygen uptake and endurance performance in healthy humans.

    Science.gov (United States)

    Ashenden, M J; Schumacher, Y O; Sharpe, K; Varlet-Marie, E; Audran, M

    2007-05-01

    Haemoglobin-based oxygen carriers (HBOCs) such as Hemopure are touted as a tenable substitute for red blood cells and therefore potential doping agents, although the mechanisms of oxygen transport of HBOCs are incompletely understood. We investigated whether infusion of Hemopure increased maximal oxygen uptake (V.O 2max) and endurance performance in healthy subjects. Twelve male subjects performed two 4-minute submaximal exercise bouts equivalent to 60 % and 75 % of V.O (2max) on a cycle ergometer, followed by a ramped incremental protocol to elicit V.O (2max). A crossover design tested the effect of infusing either 30 g (6 subjects) or 45 g (6 subjects) of Hemopure versus a placebo. Under our study conditions, Hemopure did not increase V.O (2max) nor endurance performance. However, the infusion of Hemopure caused a decrease in heart rate of approximately 10 bpm (p=0.009) and an average increase in mean ( approximately 7 mmHg) and diastolic blood pressure ( approximately 8 mmHg) (p=0.046) at submaximal and maximal exercise intensities. Infusion of Hemopure did not bestow the same physiological advantages generally associated with infusion of red blood cells. It is conceivable that under exercise conditions, the hypertensive effects of Hemopure counter the performance-enhancing effect of improved blood oxygen carrying capacity.

  16. Consumption governance toward more sustainable consumption

    NARCIS (Netherlands)

    Wahlen, S.; Dubuisson-Quellier, Sophie

    2018-01-01

    This article deliberates on strategies of consumption governance toward more sustainable consumption. We discuss theoretical concepts stemming from various social science perspectives to (1) promote more sustainable consumption, (2) compare strategies stemming from individualist understanding of

  17. Effects of submaximal exercise with water ingestion on intraocular pressure in healthy human males

    Directory of Open Access Journals (Sweden)

    Moura M.A.

    2002-01-01

    Full Text Available The effects of exercise and water replacement on intraocular pressure (IOP have not been well established. Furthermore, it is not known whether the temperature of the fluid ingested influences the IOP response. In the present study we determined the effect of water ingestion at three temperatures (10, 24 and 38ºC; 600 ml 15 min before and 240 ml 15, 30 and 45 min after the beginning of each experimental session on the IOP of six healthy male volunteers (age = 24.0 ± 3.5 years, weight = 67.0 ± 4.8 kg, peak oxygen uptake (VO2peak = 47.8 ± 9.1 ml kg-1 min-1. The subjects exercised until exhaustion on a cycle ergometer at a 60% VO2peak in a thermoneutral environment. IOP was measured before and after exercise and during recovery (15, 30 and 45 min using the applanation tonometry method. Skin and rectal temperatures, heart rate and oxygen uptake were measured continuously. IOP was similar for the right eye and the left eye and increased post-water ingestion under both exercising and resting conditions (P<0.05 but did not differ between resting and exercising situations, or between the three water temperatures. Time to exhaustion was not affected by the different water temperatures. Rectal temperature, hydration status, heart rate, oxygen uptake, carbon dioxide extraction and lactate concentration were increased by exercise but were not affected by water temperature. We conclude that IOP was not affected by exercise and that water ingestion increased IOP as expected, regardless of water temperature.

  18. Sustainable consumption

    DEFF Research Database (Denmark)

    Prothero, Andrea; Dobscha, Susan; Freund, Jim

    2011-01-01

    This essay explores sustainable consumption and considers possible roles for marketing and consumer researchers and public policy makers in addressing the many sustainability challenges that pervade our planet. Future research approaches to this interdisciplinary topic need to be comprehensive...... and systematic and will benefit from a variety of different perspectives. There are a number of opportunities for future research, and three areas are explored in detail. First, the essay considers the inconsistency between the attitudes and behaviors of consumers with respect to sustainability; next, the agenda...... is broadened to explore the role of individual citizens in society; and finally, a macro institutional approach to fostering sustainability is explored. Each of these areas is examined in detail and possible research avenues and public policy initiatives are considered within each of these separate...

  19. Influence of experimental interfering occlusal contacts on the activity of the anterior temporal and masseter muscles during submaximal and maximal bite in the intercuspal position.

    Science.gov (United States)

    Sheikholeslam, A; Riise, C

    1983-05-01

    The effects of an intercuspal occlusal interference on the pattern of activity of the anterior temporal and masseter muscles during submaximal and maximal bite, were studied in eleven volunteers with complete, natural dentitions. The results show that, during maximal and submaximal bite an occlusal interference (about 0.5 mm) in the intercuspal position is able to disturb the almost symmetric pattern of muscular activity in the anterior temporal and masseter muscles. Further, the level of muscular activity during maximal bite decreased significantly in all muscles studied. In some subjects, the decrease of muscular activity could still be observed one week after insertion of the interfering contact. After eliminating the interference, the muscular co-ordination pattern improved and the level of muscular activity increased significantly.

  20. Oxygen safety

    Science.gov (United States)

    ... sure you have working smoke detectors and a working fire extinguisher in your home. If you move around the house with your oxygen, you may need more than one fire extinguisher in different locations. Smoking can be very dangerous. No one should smoke ...

  1. Oxygen therapy - infants

    Science.gov (United States)

    ... breathe increased amounts of oxygen to get normal levels of oxygen in their blood. Oxygen therapy provides babies with the extra oxygen. Information Oxygen is a gas that the cells in your body need to work properly. The ...

  2. The Effect of Submaximal Exercise Preceded by Single Whole-Body Cryotherapy on the Markers of Oxidative Stress and Inflammation in Blood of Volleyball Players

    OpenAIRE

    Mila-Kierzenkowska, Celestyna; Jurecka, Alicja; Woźniak, Alina; Szpinda, Michał; Augustyńska, Beata; Woźniak, Bartosz

    2013-01-01

    The aim of the study was to determine the effect of single whole-body cryotherapy (WBC) session applied prior to submaximal exercise on the activity of antioxidant enzymes, the concentration of lipid peroxidation products, total oxidative status, and the level of cytokines in blood of volleyball players. The study group consisted of 18 male professional volleyball players, who were subjected to extremely cold air (−130°C) prior to exercise performed on cycloergometer. Blood samples were taken...

  3. Several submaximal exercise tests are reliable, valid and acceptable in people with chronic pain, fibromyalgia or chronic fatigue: a systematic review

    OpenAIRE

    Julia Ratter; Lorenz Radlinger; Cees Lucas

    2014-01-01

    Question: Are submaximal and maximal exercise tests reliable, valid and acceptable in people with chronic pain, fibromyalgia and fatigue disorders? Design: Systematic review of studies of the psychometric properties of exercise tests. Participants: People older than 18 years with chronic pain, fibromyalgia and chronic fatigue disorders. Intervention: Studies of the measurement properties of tests of physical capacity in people with chronic pain, fibromyalgia or chronic fatigue disorders were ...

  4. Interactions between oxygen permeation and homogeneous-phase fuel conversion on the sweep side of an ion transport membrane

    KAUST Repository

    Hong, Jongsup; Kirchen, Patrick; Ghoniem, Ahmed F.

    2013-01-01

    concentration enhances oxygen permeation substantially. This is accomplished through promoting oxidation reactions (oxygen consumption) and the transport of the products and reaction heat towards the membrane, which lowers the oxygen concentration and increases

  5. Aerobic interval training reduces vascular resistances during submaximal exercise in obese metabolic syndrome individuals.

    Science.gov (United States)

    Mora-Rodriguez, Ricardo; Fernandez-Elias, V E; Morales-Palomo, F; Pallares, J G; Ramirez-Jimenez, M; Ortega, J F

    2017-10-01

    The aim of this study was to determine the effects of high-intensity aerobic interval training (AIT) on exercise hemodynamics in metabolic syndrome (MetS) volunteers. Thirty-eight, MetS participants were randomly assigned to a training (TRAIN) or to a non-training control (CONT) group. TRAIN consisted of stationary interval cycling alternating bouts at 70-90% of maximal heart rate during 45 min day -1 for 6 months. CONT maintained baseline physical activity and no changes in cardiovascular function or MetS factors were detected. In contrast, TRAIN increased cardiorespiratory fitness (14% in VO 2PEAK ; 95% CI 9-18%) and improved metabolic syndrome (-42% in Z score; 95% CI 83-1%). After TRAIN, the workload that elicited a VO 2 of 1500 ml min -1 increased 15% (95% CI 5-25%; P exercise heart rate (109 ± 15-106 ± 13 beats min -1 ; P exercise in MetS patients. Specifically, it reduces diastolic blood pressure, systemic vascular resistances, and the double product. The reduction in double product, suggests decreased myocardial oxygen demands which could prevent the occurrence of adverse cardiovascular events during exercise in this population. CLINICALTRIALS. NCT03019796.

  6. Aquatic respiration rate measurements at low oxygen concentrations.

    Directory of Open Access Journals (Sweden)

    Moritz Holtappels

    Full Text Available Despite its huge ecological importance, microbial oxygen respiration in pelagic waters is little studied, primarily due to methodological difficulties. Respiration measurements are challenging because of the required high resolution of oxygen concentration measurements. Recent improvements in oxygen sensing techniques bear great potential to overcome these limitations. Here we compare 3 different methods to measure oxygen consumption rates at low oxygen concentrations, utilizing amperometric Clark type sensors (STOX, optical sensors (optodes, and mass spectrometry in combination with (18-18O2 labeling. Oxygen concentrations and consumption rates agreed well between the different methods when applied in the same experimental setting. Oxygen consumption rates between 30 and 400 nmol L(-1 h(-1 were measured with high precision and relative standard errors of less than 3%. Rate detection limits in the range of 1 nmol L(-1 h(-1 were suitable for rate determinations in open ocean water and were lowest at the lowest applied O2 concentration.

  7. The bilateral movement condition facilitates maximal but not submaximal paretic-limb grip force in people with post-stroke hemiparesis

    Science.gov (United States)

    DeJong, Stacey L.; Lang, Catherine E.

    2012-01-01

    Objectives Although healthy individuals have less force production capacity during bilateral muscle contractions compared to unilateral efforts, emerging evidence suggests that certain aspects of paretic upper limb task performance after stroke may be enhanced by moving bilaterally instead of unilaterally. We investigated whether the bilateral movement condition affects grip force differently on the paretic side of people with post-stroke hemiparesis, compared to their non-paretic side and both sides of healthy young adults. Methods Within a single session, we compared: 1) maximal grip force during unilateral vs. bilateral contractions on each side, and 2) force contributed by each side during a 30% submaximal bilateral contraction. Results Healthy controls produced less grip force in the bilateral condition, regardless of side (- 2.4% difference), and similar findings were observed on the non-paretic side of people with hemiparesis (- 4.5% difference). On the paretic side, however, maximal grip force was increased by the bilateral condition in most participants (+11.3% difference, on average). During submaximal bilateral contractions in each group, the two sides each contributed the same percentage of unilateral maximal force. Conclusions The bilateral condition facilitates paretic limb grip force at maximal, but not submaximal levels. Significance In some people with post-stroke hemiparesis, the paretic limb may benefit from bilateral training with high force requirements. PMID:22248812

  8. Effects of stair-climbing on balance, gait, strength, resting heart rate, and submaximal endurance in healthy seniors.

    Science.gov (United States)

    Donath, L; Faude, O; Roth, R; Zahner, L

    2014-04-01

    Stair-climbing serves as a feasible opportunity to remain physically active within everyday-life. Data on neuromuscular and cardiorespiratory performance after regular stair-climbing in seniors are scarce. Forty-eight seniors were stratified to a one- (taking every step, INT1) or two-step strategy (every second step, INT2) or a control group (CON). Thirty-nine seniors [females: n = 22, males: n = 17; age: 70.5 (SD 5.1) years; BMI: 25.8 (3.1) kg/m(2)] completed the 8-week intervention (three weekly sessions). Before and after the intervention, balance, gait, strength, and submaximal endurance (at different intensities) were assessed. Maximal strength and explosive power did not improve significantly (0.10 walking significantly decreased (-11/min; P beam balancing (4.5 cm width) increased in INT2 (P = 0.007) compared with CON. With more pronounced effects in INT2, stair-climbing significantly improved resting and exercise heart rates, perceived exertion, and dynamic balance performance in healthy seniors and may contribute to better overall fitness, reduced fall risk, and less perceived strain during daily life activities. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Effect of Cutaneous Heat Pain on Corticospinal Excitability of the Tibialis Anterior at Rest and during Submaximal Contraction

    Directory of Open Access Journals (Sweden)

    Maxime Billot

    2018-01-01

    Full Text Available Previous studies have shown that pain can interfere with motor control. The neural mechanisms underlying these effects remain largely unknown. At the upper limb, mounting evidence suggests that pain-induced reduction in corticospinal excitability is involved. No equivalent data is currently available at the lower limb. The present study therefore examined the effect of thermal pain on the corticospinal drive to tibialis anterior (TA at rest and during an isometric submaximal dorsiflexion. Transcranial magnetic stimulation was used to induce motor-evoked potentials (MEPs in the TA at rest and during contraction in the presence or absence of cutaneous heat pain induced by a thermode positioned above the TA (51°C during 1 s. With similar pain ratings between conditions (3.9/10 at rest and 3.6/10 during contraction, results indicate significant decreases in MEP amplitude during both rest (−9% and active conditions (−13% (main effect of pain, p=0.02. These results therefore suggest that cutaneous heat pain can reduce corticospinal excitability in the TA muscle and that such reduction in corticospinal excitability could contribute to the interference of pain on motor control/motor learning.

  10. Brazilian Twin Registry: A Bright Future for Twin Studies/Twin Research: Twin Study of Alcohol Consumption and Mortality; Oxygen Uptake in Adolescent Twins/In the News: Superfecundated Twins In Vietnam; Adolescent Twin Relations; Twin and Triplet Co-Workers; A Special Twin Ultrasound; Monozygotic Twins With Different Skin Color; Identical Twin Returns from Space.

    Science.gov (United States)

    Segal, Nancy L

    2016-06-01

    The establishment of the Brazilian Twin Registry for the study of genetic, social, and cultural influences on behavior is one of eleven newly funded projects in the Department of Psychology at the University of São Paulo. These 11 interrelated projects form the core of the university's Center for Applied Research on Well-Being and Human Behavior. An overview of the planned twin research and activities to date is presented. Next, two recent twin studies are reviewed, one on the relationship between alcohol consumption and mortality, and the other on factors affecting maximal oxygen uptake. Twins cited in the media include the first identified superfecundated twins in Vietnam, adolescent twin relations, twins and triplets who work together, monozygotic twins with different skin tones and a co-twin control study that addresses the effects of space travel.

  11. THE EFFECT OF LIGHT COLOUR ON THE DIEL RHYTHM OF OXYGEN CONSUMPTION RATE IN JUVENILE CHINESE SHRIMP, FENNEROPENAEUS CHINENSIS%光色对中国明对虾(Fenneropenaeus chinensis)稚虾耗氧率昼夜变化节律的影响

    Institute of Scientific and Technical Information of China (English)

    刘伟; 王芳; 钟大森; 黄国强

    2011-01-01

    The effect of light colour on the diel rhythm of the oxygen consumption rate in ju venile Fenneropenaeus chinensis with average wet body weight of (5. 507 ±0. 147)g was ex amined under a flowing water apparatus at 25. 0±0. 5℃, and the four light colours were: natural light (590nm), yellow light (580nm), green light (525 nm), and blue light (435nm) . Respectively. The results were as follows: 1 under natural light, yellow light, and green light, the oxygen consumption rate of F. Chinensis showed definite diel rhythm, the positive peak appeared at dark condition, while the negative peak appeared at illumination condition. Mean oxygen consumption rate of F. Chinensis at dark condition was significantly higher than that at illumination one (P0. 05), but the diurnal mean oxygen consumption rate of F. Chinensis under natural light was significantly lower than that under blue light treatment.%采用流水装置测定了中国明对虾(Fenneropenaeus chinensis)稚虾在4种先色处理下耗氧率的昼夜变化.实验设四种光色处理,分别为自然光(590nm)、黄光(580nm)、绿光(525 nm)和蓝光(435nm),光照周期为14L:10D,水温为25.0±0.5℃,实验虾的规格为(5.507±0.147)g.主要实验结果如下:1、在自然光、黄光和绿光下,中国明对虾耗氧率的昼夜波动较大,对虾耗氧率的高峰出现在夜间,低谷出现在日间,且对虾在夜间的平均耗氧率显著高于日间(P<0.05);在蓝光下,中国明对虾耗氧率的昼夜波动较小,对虾耗氧率的高峰出现在日间,低谷出现在夜间,且对虾在夜间和日间的平均耗氧率差异不显著(P>0.05);2、在自然光、黄光和绿光下,中国明对虾的日平均耗氧率差异不昱著(P>0.05),而对虾日平均耗氧率在蓝光和自然光下的差异显著(P<0.05).

  12. Pharmaceutical preparation of oxygen-15 labelled molecular oxygen and carbon monoxide gasses in a hospital setting.

    NARCIS (Netherlands)

    Luurtsema, Geert; Boellaard, Ronald; Greuter, Henri; Rijbroek, Abraham; Takkenkamp, Kevin; de Geest, Frank; Buijs, Fred; Hendrikse, NH; Franssen, Eric; van Lingen, Arthur; Lammertsma, Adriaan A.

    BACKGROUND: Clinical positron emission tomography (PET) requires safe and effective PET radiopharmaceuticals. Tracers used for measuring oxygen consumption and blood volume are [(15)O]O(2) and [(15)O]CO, respectively. In general, these oxygen-15 labelled tracers are produced using a cyclotron that

  13. Submaximal exercise training, more than dietary selenium supplementation, improves antioxidant status and ameliorates exercise-induced oxidative damage to skeletal muscle in young equine athletes.

    Science.gov (United States)

    White, S H; Warren, L K

    2017-02-01

    Exercise is associated with increased production of reactive oxygen species (ROS) as metabolism is upregulated to fuel muscle activity. If antioxidant systems become overwhelmed, ROS can negatively affect health and performance. Adaptation to exercise through regular training has been shown to improve defense against oxidative insult. Given selenium's role as an antioxidant, we hypothesized that increased Se intake would further enhance skeletal muscle adaptations to training. Quarter Horse yearlings (18 ± 0.2 mo; 402 ± 10 kg) were randomly assigned to receive either 0.1 or 0.3 mg Se/kg DM and placed in either an untrained or a trained (30 min walk-trot-canter, 4 d/wk) group for 14 wk. Phase 1 (wk 1 to 8) consisted of 4 treatments: trained and fed 0.1 mg Se/kg DM through wk 14 (CON-TR; n = 10), trained and fed 0.3 mg Se/kg DM through wk 14 (HIGH-TR; n = 10), untrained and fed 0.1 mg Se/kg DM through wk 14 (CON-UN; n = 5), or untrained and fed 0.3 mg Se/kg DM through wk 14 (HIGH-UN; n = 5). During Phase 2 (wk 9 to 14), dietary Se level in half of the trained horses was reversed, resulting in 6 treatments: CON-TR (n = 5), trained and fed 0.1 mg/kg Se in Phase 1 and then switched to 0.3 mg/kg Se for Phase 2 (ADD-TR; n = 5), trained and fed 0.3 mg/kg Se in Phase 1 and then switched to 0.1 mg/kg Se for Phase 2 (DROP-TR; n = 5), HIGH-TR (n = 5), CON-UN (n = 5), or HIGH-UN (n = 5). All horses underwent a 120-min submaximal exercise test (SET) at the end of Phase 1 (SET 1) and 2 (SET 2). Blood samples and biopsies from the middle gluteal muscle were collected before and after each phase of the study and in response to each SET and analyzed for markers of oxidative damage and antioxidant enzyme activity. In both phases, serum Se was higher (P creatine kinase (CK) activity was lower in trained horses than in untrained horses (P < 0.0001), indicating less muscle damage, but plasma lipid hydroperoxides (LPO) and muscle GPx and SOD activities were unaffected by training or Se

  14. Early diagenesis in the Congo deep-sea fan sediments dominated by massive terrigenous deposits: Part I - Oxygen consumption and organic carbon mineralization using a micro-electrode approach

    Science.gov (United States)

    Pozzato, Lara; Cathalot, Cécile; Berrached, Chabha; Toussaint, Flora; Stetten, Elsa; Caprais, Jean-Claude; Pastor, Lucie; Olu, Karine; Rabouille, Christophe

    2017-08-01

    Organic matter (OM) transfer from the continent to the ocean occurs across margins which constitute a major area of OM recycling and burial. The lobe complex of the Congo deep-sea fan is connected to the river mouth by a canyon and alimented by recurrent turbidity currents, containing a large proportion of labile terrigenous OM and producing high sedimentation rates. These inputs support the development of ecosystems harboring rich assemblages of vesicomyid bivalves and bacterial mats, called Habitats. Here, we present O2 microprofiles and diffusive oxygen uptake rates (DOUs) obtained during the CONGOLOBE project at six sites of this active lobe complex by in situ and on-board methods based on micro-electrode profiling. The dataset is used to determine remineralization rates and study the biogeochemical dynamics of different ecosystems of the lobe area, in order to compare levee and background sediments to the Habitats developed on the flanks of the main turbiditic channel. Levee and background sediments are characterized by significantly higher DOUs than abyssal sediments at 5000 m meters depth (2-5 mmol O2 m-2 d-1versus 1.5-2.5 mmol O2 m-2 d-1) and the Habitats are hotspots of OM remineralization with DOU values ranging between 8 and 40 mmol O2 m-2 d-1. By comparing sites near the active channel to a site located 50 km away, we show that the lobe connection to the main turbiditic channel is vital to the dense benthic communities.

  15. Oxygen dependence of respiration in rat spinotrapezius muscle in situ

    OpenAIRE

    Golub, Aleksander S.; Pittman, Roland N.

    2012-01-01

    The oxygen dependence of respiration in striated muscle in situ was studied by measuring the rate of decrease of interstitial Po2 [oxygen disappearance curve (ODC)] following rapid arrest of blood flow by pneumatic tissue compression, which ejected red blood cells from the muscle vessels and made the ODC independent from oxygen bound to hemoglobin. After the contribution of photo-consumption of oxygen by the method was evaluated and accounted for, the corrected ODCs were converted into the Po...

  16. Effects of Barbell Deadlift Training on Submaximal Motor Unit Firing Rates for the Vastus Lateralis and Rectus Femoris

    Science.gov (United States)

    Stock, Matt S.; Thompson, Brennan J.

    2014-01-01

    Previous investigations that have studied motor unit firing rates following strength training have been limited to small muscles, isometric training, or interventions involving exercise machines. We examined the effects of ten weeks of supervised barbell deadlift training on motor unit firing rates for the vastus lateralis and rectus femoris during a 50% maximum voluntary contraction (MVC) assessment. Twenty-four previously untrained men (mean age  = 24 years) were randomly assigned to training (n = 15) or control (n = 9) groups. Before and following the intervention, the subjects performed isometric testing of the right knee extensors while bipolar surface electromyographic signals were detected from the two muscles. The signals were decomposed into their constituent motor unit action potential trains, and motor units that demonstrated accuracy levels less than 92.0% were not considered for analysis. One thousand eight hundred ninety-two and 2,013 motor units were examined for the vastus lateralis and rectus femoris, respectively. Regression analyses were used to determine the linear slope coefficients (pulses per second [pps]/% MVC) and y-intercepts (pps) of the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. Deadlift training significantly improved knee extensor MVC force (Cohen's d = .70), but did not influence force steadiness. Training had no influence on the slopes and y-intercepts for the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. In agreement with previous cross-sectional comparisons and randomized control trials, our findings do not support the notion that strength training affects the submaximal control of motor units. PMID:25531294

  17. Effects of barbell deadlift training on submaximal motor unit firing rates for the vastus lateralis and rectus femoris.

    Directory of Open Access Journals (Sweden)

    Matt S Stock

    Full Text Available Previous investigations that have studied motor unit firing rates following strength training have been limited to small muscles, isometric training, or interventions involving exercise machines. We examined the effects of ten weeks of supervised barbell deadlift training on motor unit firing rates for the vastus lateralis and rectus femoris during a 50% maximum voluntary contraction (MVC assessment. Twenty-four previously untrained men (mean age  = 24 years were randomly assigned to training (n = 15 or control (n = 9 groups. Before and following the intervention, the subjects performed isometric testing of the right knee extensors while bipolar surface electromyographic signals were detected from the two muscles. The signals were decomposed into their constituent motor unit action potential trains, and motor units that demonstrated accuracy levels less than 92.0% were not considered for analysis. One thousand eight hundred ninety-two and 2,013 motor units were examined for the vastus lateralis and rectus femoris, respectively. Regression analyses were used to determine the linear slope coefficients (pulses per second [pps]/% MVC and y-intercepts (pps of the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. Deadlift training significantly improved knee extensor MVC force (Cohen's d = .70, but did not influence force steadiness. Training had no influence on the slopes and y-intercepts for the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. In agreement with previous cross-sectional comparisons and randomized control trials, our findings do not support the notion that strength training affects the submaximal control of motor units.

  18. Effect of strength training with blood flow restriction on muscle power and submaximal strength in eumenorrheic women.

    Science.gov (United States)

    Gil, Ana L S; Neto, Gabriel R; Sousa, Maria S C; Dias, Ingrid; Vianna, Jeferson; Nunes, Rodolfo A M; Novaes, Jefferson S

    2017-03-01

    Blood flow restriction (BFR) training stimulates muscle size and strength by increasing muscle activation, accumulation of metabolites and muscle swelling. This method has been used in different populations, but no studies have evaluated the effects of training on muscle power and submaximal strength (SS) in accounted for the menstrual cycle. The aim of this study was to analyse the effect of strength training (ST) with BFR on the muscle power and SS of upper and lower limbs in eumenorrheic women. Forty untrained women (18-40 years) were divided randomly and proportionally into four groups: (i) high-intensity ST at 80% of 1RM (HI), (ii) low-intensity ST at 20% of 1RM combined with partial blood flow restriction (LI + BFR), (iii) low-intensity ST at 20% of 1RM (LI) and d) control group (CG). Each training group performed eight training sessions. Tests with a medicine ball (MB), horizontal jump (HJ), vertical jump (VJ), biceps curls (BC) and knee extension (KE) were performed during the 1st day follicular phase (FP), 14th day (ovulatory phase) and 26-28th days (luteal phase) of the menstrual cycle. There was no significant difference among groups in terms of the MB, HJ, VJ or BC results at any time point (P>0·05). SS in the KE exercise was significantly greater in the LI + BFR group compared to the CG group (P = 0·014) during the LP. Therefore, ST with BFR does not appear to improve the power of upper and lower limbs and may be an alternative to improve the SS of lower limbs of eumenorrheic women. © 2015 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  19. Estimating Neural Control from Concentric vs. Eccentric Surface Electromyographic Representations during Fatiguing, Cyclic Submaximal Back Extension Exercises

    Directory of Open Access Journals (Sweden)

    Gerold R. Ebenbichler

    2017-05-01

    Full Text Available Purpose: To investigate the differences in neural control of back muscles activated during the eccentric vs. the concentric portions of a cyclic, submaximal, fatiguing trunk extension exercise via the analysis of amplitude and time-frequency parameters derived from surface electromyographic (SEMG data.Methods: Using back dynamometers, 87 healthy volunteers performed three maximum voluntary isometric trunk extensions (MVC's, an isometric trunk extension at 80% MVC, and 25 cyclic, dynamic trunk extensions at 50% MVC. Dynamic testing was performed with the trunk angular displacement ranging from 0° to 40° and the trunk angular velocity set at 20°/s. SEMG data was recorded bilaterally from the iliocostalis lumborum at L1, the longissimus dorsi at L2, and the multifidus muscles at L5. The initial value and slope of the root mean square (RMS-SEMG and the instantaneous median frequency (IMDF-SEMG estimates derived from the SEMG recorded during each exercise cycle were used to investigate the differences in MU control marking the eccentric vs. the concentric portions of the exercise.Results: During the concentric portions of the exercise, the initial RMS-SEMG values were almost twice those observed during the eccentric portions of the exercise. The RMS-SEMG values generally increased during the concentric portions of the exercise while they mostly remained unchanged during the eccentric portions of the exercise with significant differences between contraction types. Neither the initial IMDF-SEMG values nor the time-course of the IMDF-SEMG values significantly differed between the eccentric and the concentric portions of the exercise.Conclusions: The comparison of the investigated SEMG parameters revealed distinct neural control strategies during the eccentric vs. the concentric portions of the cyclic exercise. We explain these differences by relying upon the principles of orderly recruitment and common drive governing motor unit behavior.

  20. Effects of barbell deadlift training on submaximal motor unit firing rates for the vastus lateralis and rectus femoris.

    Science.gov (United States)

    Stock, Matt S; Thompson, Brennan J

    2014-01-01

    Previous investigations that have studied motor unit firing rates following strength training have been limited to small muscles, isometric training, or interventions involving exercise machines. We examined the effects of ten weeks of supervised barbell deadlift training on motor unit firing rates for the vastus lateralis and rectus femoris during a 50% maximum voluntary contraction (MVC) assessment. Twenty-four previously untrained men (mean age  = 24 years) were randomly assigned to training (n = 15) or control (n = 9) groups. Before and following the intervention, the subjects performed isometric testing of the right knee extensors while bipolar surface electromyographic signals were detected from the two muscles. The signals were decomposed into their constituent motor unit action potential trains, and motor units that demonstrated accuracy levels less than 92.0% were not considered for analysis. One thousand eight hundred ninety-two and 2,013 motor units were examined for the vastus lateralis and rectus femoris, respectively. Regression analyses were used to determine the linear slope coefficients (pulses per second [pps]/% MVC) and y-intercepts (pps) of the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. Deadlift training significantly improved knee extensor MVC force (Cohen's d = .70), but did not influence force steadiness. Training had no influence on the slopes and y-intercepts for the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. In agreement with previous cross-sectional comparisons and randomized control trials, our findings do not support the notion that strength training affects the submaximal control of motor units.

  1. Oxygen depletion of bismuth molybdates

    Energy Technology Data Exchange (ETDEWEB)

    Yong, L.K.; Howe, R.F.; Keulks, G.W.; Hall, W.K.

    1978-05-01

    Pure ..cap alpha..-phase bismuth molybdate (Bi/sub 2/Mo/sub 3/O/sub 12/), which is known to be weakly active for selective oxidation, and pure ..gamma..-phase bismuth molybdate (Bi/sub 2/MoO/sub 6/), which has good activity, were subjected to oxidation-reduction cycles with known amounts of hydrogen and oxygen, at 300/sup 0/-570/sup 0/C and with evacuation steps between treatments. The volume of oxygen consumed during reoxidation was equal to half the hydrogen consumed during the reduction on the ..cap alpha..-phase, which indicated that no hydrogen was retained during reduction. For the ..gamma..-phase, the oxygen consumption was greater than half of the hydrogen consumption and it increased with extent of reduction. The excess oxygen was apparently consumed by filling anion vacancies formed during outgassing subsequent to the reduction step. ESR spectroscopy and temperature-programed oxidation-reduction indicated that lattice oxide ions which bridge between bismuth and molybdenum layers of the koechlinite structure become more labile when the catalyst is in a partially reduced state, and that this effect is greater in the ..gamma..- than the ..cap alpha..-phase. Table and 15 references.

  2. Human skeletal muscle type 1 fibre distribution and response of stress-sensing proteins along the titin molecule after submaximal exhaustive exercise.

    Science.gov (United States)

    Koskinen, Satu O A; Kyröläinen, Heikki; Flink, Riina; Selänne, Harri P; Gagnon, Sheila S; Ahtiainen, Juha P; Nindl, Bradley C; Lehti, Maarit

    2017-11-01

    Early responses of stress-sensing proteins, muscle LIM protein (MLP), ankyrin repeat proteins (Ankrd1/CARP and Ankrd2/Arpp) and muscle-specific RING finger proteins (MuRF1 and MuRF2), along the titin molecule were investigated in the present experiment after submaximal exhaustive exercise. Ten healthy men performed continuous drop jumping unilaterally on a sledge apparatus with a submaximal height until complete exhaustion. Five stress-sensing proteins were analysed by mRNA measurements from biopsies obtained immediately and 3 h after the exercise from exercised vastus lateralis muscle while control biopsies were obtained from non-exercised legs before the exercise. Decreased maximal jump height and increased serum creatine kinase activities as indirect markers for muscle damage and HSP27 immunostainings on muscle biopsies as a direct marker for muscle damage indicated that the current exercised protocol caused muscle damage. mRNA levels for four (MLP, Ankrd1/CARP, MuRF1 and MuRF2) out of the five studied stress sensors significantly (p exercise. The magnitude of MLP and Ankrd2 responses was related to the proportion of type 1 myofibres. Our data showed that the submaximal exhaustive exercise with subject's own physical fitness level activates titin-based stretch-sensing proteins. These results suggest that both degenerative and regenerative pathways are activated in very early phase after the exercise or probably already during the exercise. Activation of these proteins represents an initial step forward adaptive remodelling of the exercised muscle and may also be involved in the initiation of myofibre repair.

  3. Several submaximal exercise tests are reliable, valid and acceptable in people with chronic pain, fibromyalgia or chronic fatigue: a systematic review.

    Science.gov (United States)

    Ratter, Julia; Radlinger, Lorenz; Lucas, Cees

    2014-09-01

    Are submaximal and maximal exercise tests reliable, valid and acceptable in people with chronic pain, fibromyalgia and fatigue disorders? Systematic review of studies of the psychometric properties of exercise tests. People older than 18 years with chronic pain, fibromyalgia and chronic fatigue disorders. Studies of the measurement properties of tests of physical capacity in people with chronic pain, fibromyalgia or chronic fatigue disorders were included. Studies were required to report: reliability coefficients (intraclass correlation coefficient, alpha reliability coefficient, limits of agreements and Bland-Altman plots); validity coefficients (intraclass correlation coefficient, Spearman's correlation, Kendal T coefficient, Pearson's correlation); or dropout rates. Fourteen studies were eligible: none had low risk of bias, 10 had unclear risk of bias and four had high risk of bias. The included studies evaluated: Åstrand test; modified Åstrand test; Lean body mass-based Åstrand test; submaximal bicycle ergometer test following another protocol other than Åstrand test; 2-km walk test; 5-minute, 6-minute and 10-minute walk tests; shuttle walk test; and modified symptom-limited Bruce treadmill test. None of the studies assessed maximal exercise tests. Where they had been tested, reliability and validity were generally high. Dropout rates were generally acceptable. The 2-km walk test was not recommended in fibromyalgia. Moderate evidence was found for reliability, validity and acceptability of submaximal exercise tests in patients with chronic pain, fibromyalgia or chronic fatigue. There is no evidence about maximal exercise tests in patients with chronic pain, fibromyalgia and chronic fatigue. Copyright © 2014. Published by Elsevier B.V.

  4. Influence of obstructive sleep apnea syndrome in the fluctuation of the submaximal isometric torque of knee extensors in patients with early-grade osteoarthritis

    Science.gov (United States)

    Silva, Andressa; Mello, Marco T.; Serrão, Paula R.; Luz, Roberta P.; Bittencourt, Lia R.; Mattiello, Stela M.

    2015-01-01

    OBJECTIVE: The aim of this study was to investigate whether obstructive sleep apnea (OSA) alters the fluctuation of submaximal isometric torque of the knee extensors in patients with early-grade osteoarthritis (OA). METHOD: The study included 60 male volunteers, aged 40 to 70 years, divided into four groups: Group 1 (G1) - Control (n=15): without OA and without OSA; Group 2 (G2) (n=15): with OA and without OSA; Group 3 (G3) (n=15): without OA and with OSA; and Group 4 (G4) (n=15) with OA and with OSA. Five patients underwent maximal isometric contractions of 10 seconds duration each, with the knee at 60° of flexion to determine peak torque at 60°. To evaluate the fluctuation of torque, 5 submaximal isometric contractions (50% of maximum peak torque) of 10 seconds each, which were calculated from the standard deviation of torque and coefficient of variation, were performed. RESULTS: Significant differences were observed between groups for maximum peak torque, while G4 showed a lower value compared with G1 (p=0.005). Additionally, for the average torque exerted, G4 showed a lower value compared to the G1 (p=0.036). However, no differences were found between the groups for the standard deviation (p=0.844) and the coefficient of variation (p=0.143). CONCLUSION: The authors concluded that OSA did not change the parameters of the fluctuation of isometric submaximal torque of knee extensors in patients with early-grade OA. PMID:26443974

  5. Energy consumption: energy consumption in mainland Norway

    Energy Technology Data Exchange (ETDEWEB)

    Magnussen, Inger Helene; Killingland, Magnus; Spilde, Dag

    2012-07-25

    The purpose of this report is to describe trends in energy consumption in mainland Norway, with an emphasis on key trends within the largest consumer groups. We also explain common terms and concepts in the field of energy consumption. Finally, we look at forecasts for future energy consumption, produced by bodies outside NVE. Total final energy consumption in mainland Norway in 2009 was 207 TWh. The most important end-user groups are households, service industries, manufacturing industry and transport. In addition, the energy sector in mainland Norway consumed 15 TWh. Energy consumed in the energy sector is not considered as final consumption, as the energy is used to produce new energy products. The long-term trend in energy consumption in mainland Norway is that fuel in the transport sector and electricity for the energy sector increases, while energy consumption in other sectors flattens out. The main reason for an increased use of fuel in the transport sector is the rise in the number of motorised machinery and vehicles in mainland Norway. This has caused a rise in gasoline and diesel consumption of 75 per cent since 1976. The petroleum sector is the largest consumer of energy within the energy sector in mainland Norway, and electricity from onshore to platforms in the North Sea and to new shore side installations has led to a rise in electricity consumption from 1 TWh in 1995 to 5 TWh in 2009. The energy consumption in households showed flat trend from 1996 to 2009, after many years of growth. The main reasons are a warmer climate, higher energy prices, the use of heats pumps and more energy-efficient buildings. In the service industries, the growth in energy consumptions has slightly decreased since the late 1990s, for much the same reasons as for households. In manufacturing industries the energy consumption have flatten out mainly due to the closure of energy-intensive businesses and the establishment of new more energy-efficient businesses. Electricity is

  6. El ejercicio físico aeróbico incrementa la vasodilatación dependiente del endotelio y el consumo de oxígeno de mujeres primigestantes saludables. Ensayo clínico controlado, aleatorizado. NCT00741312 Aerobic physical exercise increases endothelium-dependent vasodilation and oxygen consumption in healthy primigravida. Controlled randomized clinical trial. NCT00741312

    Directory of Open Access Journals (Sweden)

    Róbinson Ramírez-Vélez

    2010-12-01

    Full Text Available OBJETIVO: evaluar el efecto del ejercicio aeróbico en la función dependiente del endotelio (VDE y en el consumo de oxígeno en mujeres primigestantes. MÉTODOS: ensayo clínico controlado, enmascarado y aleatorizado, llevado a cabo en 67 mujeres saludables, primigestantes, entre 16 a 20 semanas de gestación. Grupo de intervención: ejercicio aeróbico entre 50% y 65% de la frecuencia cardiaca máxima, durante 45 minutos, tres veces por semana, durante dieciséis semanas. Grupo control: actividad física habitual. Mediciones: VDE: vasodilatación mediada por flujo (VMF, consumo de oxígeno VO2max: prueba de caminata de seis minutos; antropometría: peso y talla. RESULTADOS: en las mediciones iniciales no se encontraron diferencias entre grupos en ninguna de las variables. Al finalizar la intervención, las participantes que realizaron ejercicio tenían mayor capacidad física, medida por la distancia recorrida en el test de caminata (p=0,043 y por el VO2max (p=0,023. Además, el grupo de ejercicio tuvo menor frecuencia cardiaca en reposo y mayor VMF que el grupo control (pOBJECTIVE: evaluate the effect of aerobic exercise on endothelium-dependent function (EDF and oxygen consumption in primigravida. METHODS: double-blind, randomized controlled clinical trial carried out in primigravida between 16 to 20 weeks of gestation. The intervention group had aerobic exercise between 50% to 65% of the maximum heart rate during 45 minutes, three times a week for sixteen weeks. The control group had habitual physical activity. MEASUREMENTS REALIZED: EDF: flow-mediated dilation (FMD, oxygen consumption VO2max: 6 minute walking test, anthropometry: weight and size. RESULTS: no differences were found between the two groups in any variables in the initial measurements. At the end of the intervention, participants who exercised had greater physical capacity, measured by the distance covered in walking test (p = 0.043 and VO2max (p = 0.023. In addition, the

  7. Evaluation of respiratory dynamics by volumetric capnography during submaximal exercise protocol of six minutes on treadmill in cystic fibrosis patients.

    Science.gov (United States)

    Parazzi, Paloma L F; Marson, Fernando A L; Ribeiro, Maria A G O; Schivinski, Camila I S; Ribeiro, José D

    2017-11-29

    Volumetric capnography provides the standard CO 2 elimination by the volume expired per respiratory cycle and is a measure to assess pulmonary involvement. Thus, the objective of this study was to evaluate the respiratory dynamics of healthy control subjects and those with cystic fibrosis in a submaximal exercise protocol for six minutes on the treadmill, using volumetric capnography parameters (slope 3 [Slp3], Slp3/tidal volume [Slp3/TV], and slope 2 [Slp2]). This was a cross-sectional study with 128 subjects (cystic fibrosis, 64 subjects; controls, 64 subjects]. Participants underwent volumetric capnography before, during, and after six minutes on the treadmill. Statistical analysis was performed using the Friedman, Mann-Whitney, and Kruskal-Wallis tests, considering age and sex. An alpha=0.05 was considered. Six minutes on the treadmill evaluation: in cystic fibrosis, volumetric capnography parameters were different before, during, and after six minutes on the treadmill; the same was observed for the controls, except for Slp2. Regarding age, an Slp3 difference was observed in cystic fibrosis patients regardless of age, at all moments, and in controls for age≥12 years; a difference in Slp3/TV was observed in cystic fibrosis and controls, regardless of age; and an Slp2 difference in the cystic fibrosis, regardless of age. Regarding sex, Slp3 and Slp3/TV differences were observed in cystic fibrosis regardless of sex, and in controls in male participants; an Slp2 difference was observed in the cystic fibrosis and female participants. The analysis between groups (cystic fibrosis and controls) indicated that Slp3 and Slp3/TV has identified the CF, regardless of age and sex, while the Slp2 showed the CF considering age. Cystic fibrosis showed greater values of the parameters before, during, and after exercise, even when stratified by age and sex, which may indicate ventilation inhomogeneity in the peripheral pathways in the cystic fibrosis. Copyright © 2017

  8. Consumption Habits and Humps

    DEFF Research Database (Denmark)

    Kraft, Holger; Munk, Claus; Seifried, Frank Thomas

    2017-01-01

    We show that the optimal consumption of an individual over the life cycle can have the hump shape (inverted U-shape) observed empirically if the preferences of the individual exhibit internal habit formation. In the absence of habit formation, an impatient individual would prefer a decreasing...... consumption path over life. However, because of habit formation, a high initial consumption would lead to high required consumption in the future. To cover the future required consumption, wealth is set aside, but the necessary amount decreases with age which allows consumption to increase in the early part...... of life. At some age, the impatience outweighs the habit concerns so that consumption starts to decrease. We derive the optimal consumption strategy in closed form, deduce sufficient conditions for the presence of a consumption hump, and characterize the age at which the hump occurs. Numerical examples...

  9. Consumption Habits and Humps

    DEFF Research Database (Denmark)

    Kraft, Holger; Munk, Claus; Seifried, Frank Thomas

    We show that the optimal consumption of an individual over the life cycle can have the hump shape (inverted U-shape) observed empirically if the preferences of the individual exhibit internal habit formation. In the absence of habit formation, an impatient individual would prefer a decreasing...... consumption path over life. However, because of habit formation, a high initial consumption would lead to high required consumption in the future. To cover the future required consumption, wealth is set aside, but the necessary amount decreases with age which allows consumption to increase in the early part...... of life. At some age, the impatience outweighs the habit concerns so that consumption starts to decrease. We derive the optimal consumption strategy in closed form, deduce sufficient conditions for the presence of a consumption hump, and characterize the age at which the hump occurs. Numerical examples...

  10. Nitric Oxide is Required for Homeostasis of Oxygen and Reactive Oxygen Species in Barley Roots under Aerobic Conditions

    DEFF Research Database (Denmark)

    Gupta, Kapuganti J; Hebelstrup, Kim; Kruger, Nicholas J

    2014-01-01

    Oxygen, the terminal electron acceptor for mitochondrial electron transport, is vital for plants because of its role in the production of ATP by oxidative phosphorylation. While photosynthetic oxygen production contributes to the oxygen supply in leaves, reducing the risk of oxygen limitation of ...... electron transport chain (Gupta et al., 2011). Thus, NO could influence oxygen consumption under normal aerobic conditions in roots, and it is this specific function that is assessed here.......Oxygen, the terminal electron acceptor for mitochondrial electron transport, is vital for plants because of its role in the production of ATP by oxidative phosphorylation. While photosynthetic oxygen production contributes to the oxygen supply in leaves, reducing the risk of oxygen limitation...

  11. Lifetime of the internal reference oxygen sensor

    DEFF Research Database (Denmark)

    Hu, Qiang; Jacobsen, Torben; Hansen, Karin Vels

    2013-01-01

    The internal reference oxygen sensor (IROS) based on a binary mixture of metal and its stoichiometric oxide is subject to leaks that result in consumption of the binary mixture. An IROS loses the functionality when the binary mixture is exhausted. Among the possible leak sources the electronic leak...

  12. Energy Consumption Database

    Science.gov (United States)

    Consumption Database The California Energy Commission has created this on-line database for informal reporting ) classifications. The database also provides easy downloading of energy consumption data into Microsoft Excel (XLSX

  13. Does recombinant human Epo increase exercise capacity by means other than augmenting oxygen transport?

    DEFF Research Database (Denmark)

    Lundby, C; Robach, P; Boushel, R

    2008-01-01

    This study was performed to test the hypothesis that administration of recombinant human erythropoietin (rHuEpo) in humans increases maximal oxygen consumption by augmenting the maximal oxygen carrying capacity of blood. Systemic and leg oxygen delivery and oxygen uptake were studied during...... before rHuEpo treatment). Blood buffer capacity remained unaffected by rHuEpo treatment and hemodilution. The augmented hematocrit did not compromise peak cardiac output. In summary, in healthy humans, rHuEpo increases maximal oxygen consumption due to augmented systemic and muscular peak oxygen delivery....

  14. Placental Gas Exchange and the Oxygen Supply to the Fetus

    DEFF Research Database (Denmark)

    Carter, Anthony M

    2015-01-01

    The oxygen supply of the fetus depends on the blood oxygen content and flow rate in the uterine and umbilical arteries and the diffusing capacity of the placenta. Oxygen consumption by the placenta is a significant factor and a potential limitation on availability to the fetus. The relevance...... anaerobic conditions and even the fetus is adapted to a low oxygen environment. Nevertheless, there is a reserve capacity, and during acute hypoxia the fetus can counter a 50% reduction in oxygen delivery by increasing fractional extraction. During sustained hypoxia, on the other hand, fetal growth...

  15. Modeling and experimental methods to predict oxygen distribution in bone defects following cell transplantation.

    Science.gov (United States)

    Heylman, Christopher M; Santoso, Sharon; Krebs, Melissa D; Saidel, Gerald M; Alsberg, Eben; Muschler, George F

    2014-04-01

    We have developed a mathematical model that allows simulation of oxygen distribution in a bone defect as a tool to explore the likely effects of local changes in cell concentration, defect size or geometry, local oxygen delivery with oxygen-generating biomaterials (OGBs), and changes in the rate of oxygen consumption by cells within a defect. Experimental data for the oxygen release rate from an OGB and the oxygen consumption rate of a transplanted cell population are incorporated into the model. With these data, model simulations allow prediction of spatiotemporal oxygen concentration within a given defect and the sensitivity of oxygen tension to changes in critical variables. This information may help to minimize the number of experiments in animal models that determine the optimal combinations of cells, scaffolds, and OGBs in the design of current and future bone regeneration strategies. Bone marrow-derived nucleated cell data suggest that oxygen consumption is dependent on oxygen concentration. OGB oxygen release is shown to be a time-dependent function that must be measured for accurate simulation. Simulations quantify the dependency of oxygen gradients in an avascular defect on cell concentration, cell oxygen consumption rate, OGB oxygen generation rate, and OGB geometry.

  16. Muscle mitochondrial capacity exceeds maximal oxygen delivery in humans

    DEFF Research Database (Denmark)

    Boushel, Robert Christopher; Gnaiger, Erich; Calbet, Jose A L

    2011-01-01

    Across a wide range of species and body mass a close matching exists between maximal conductive oxygen delivery and mitochondrial respiratory rate. In this study we investigated in humans how closely in-vivo maximal oxygen consumption (VO(2) max) is matched to state 3 muscle mitochondrial respira...

  17. Oxygen consumption in Mediterranean octocorals under different temperatures

    NARCIS (Netherlands)

    Previati, M.; Scinto, A.; Cerrano, C.; Osinga, R.

    2010-01-01

    Ecosystem resilience to climate anomalies is related to the physiological plasticity of organisms. To characterize the physiological response of some common Mediterranean gorgonians to fluctuations in temperature, four species (Paramuricea clavata, Eunicella singularis, Eunicella cavolinii and

  18. Heat release from wood wall assemblies using oxygen consumption method

    Science.gov (United States)

    Hao C. Tran; Robert E. White

    1990-01-01

    The concept of heat release rate is gaining acceptance in the evaluation of fire performance of materials and assemblies. However, this concept has not been incorporated into fire endurance testing such as the ASTM E-119 test method. Heat release rate of assemblies can be useful in determining the time at which the assemblies start to contribute to the controlled fire...

  19. Water hardness and the effects of Cd on oxygen consumption ...

    African Journals Online (AJOL)

    DRINIE

    2004-01-01

    Jan 1, 2004 ... regulatory and acid-base balance disturbances (Goss and Wood,. 1988). An increase in .... tanks, tap water and from a borehole at the farm Rooipoort 29 ..... lethal environmental copper exposure on the energy metabolism of.

  20. [Study of oxygen consumption in infants of diabetic mothers].

    Science.gov (United States)

    Courpotin, C; Keenan, W J; Sutherland, J M; Gerbeaux, J

    1975-01-01

    The energy expenditure (VO2) was measured during the first 36 hours of life in 10 infants of diabetic mothers (IDM) and in 16 normal newborns (NB). The mean VO2 was 5,72 ml/kg/min +/- 0,4 for the NB and 4,94 ml/kg/min. +/- 0,3 for the IDM. The respiratory quotients were similar for both groups. Blood glucose determination from all IDM were greater than 44 mg%. Although the low VO2 for IDM is unexplained, several hypothesis might be anticipated: either lack of utilization of abundant endogenous glycogen stores or increased metabolism of glucose by the cells.

  1. Oxygen sensitization of mammalian cells under different irradiation conditions

    International Nuclear Information System (INIS)

    Ling, C.C.; Michaels, H.B.; Gerweck, L.E.; Epp, E.R.; Peterson, E.C.

    1981-01-01

    The oxygen dependence of the radiosensitivity of cultured CHO cells was examined in detail with particular attention paid to avoiding possible artifacts due to radiolytic oxygen depletion. Two methods of gas equilibration and irradiation were used. In the first approach, cells were irradiated with 50-kVp X rays in a thin-layer geometry which offered maximum interchange between the cells and the surrounding gas. The second technique employed 280-kVp X irradiation of cells under full-medium conditions with mechanical agitation to minimize the effect of radiochemical oxygen consumption by promoting rapid oxygen replenishment. With these techniques oxygen radiosensitization was clearly resolved at an oxygen concentration of 0.03% in the gas phase. The oxygen K curves measured by these two methods were similar in shape over a wide range of oxygen concentration

  2. The Impact of Firefighter Personal Protective Equipment and Treadmill Protocol on Maximal Oxygen Uptake

    Science.gov (United States)

    Lee, Joo-Young; Bakri, Ilham; Kim, Jung-Hyun; Son, Su-Young; Tochihara, Yutaka

    2015-01-01

    This study investigated the effects of firefighter personal protective equipment (PPE) on the determination of maximal oxygen uptake (VO2max) while using two different treadmill protocols: a progressive incline protocol (PIP) and a progressive speed protocol (PSP), with three clothing conditions (Light-light clothing; Boots-PPE with rubber boots; Shoes-PPE with running shoes). Bruce protocol with Light was performed for a reference test. Results showed there was no difference in VO2max between Bruce Light, PIP Light, and PSP Light. However, VO2max was reduced in Boots and Shoes with shortened maximal performance time (7 and 6 min reduced for PIP Boots and Shoes, respectively; 11 and 9 min reduced for PSP Boots and Shoes, respectively), whereas the increasing rate of VO2 in Boots and Shoes during submaximal exercise was greater compared with Light. Wearing firefighter boots compared with wearing running shoes also significantly affected submaximal VO2 but not VO2max. These results suggest that firefighters’ maximal performance determined from a typical VO2max test without wearing PPE may overestimate the actual performance capability of firefighters wearing PPE. PMID:23668854

  3. Aerobic Microbial Respiration In Oceanic Oxygen Minimum Zones

    DEFF Research Database (Denmark)

    Kalvelage, Tim; Lavik, Gaute; Jensen, Marlene Mark

    2015-01-01

    Namibia and Peru. Experiments with additions of double-labelled oxygen revealed high aerobic activity in the upper OMZs, likely controlled by surface organic matter export. Consistently observed oxygen consumption in samples retrieved throughout the lower OMZs hints at efficient exploitation of vertically...... and laterally advected, oxygenated waters in this zone by aerobic microorganisms. In accordance, metagenomic and metatranscriptomic analyses identified genes encoding for aerobic terminal oxidases and demonstrated their expression by diverse microbial communities, even in virtually anoxic waters. Our results...

  4. The effect of local skin cooling before a sustained, submaximal isometric contraction on fatigue and isometric quadriceps femoris performance: A randomized controlled trial.

    Science.gov (United States)

    Hohenauer, Erich; Cescon, Corrado; Deliens, Tom; Clarys, Peter; Clijsen, Ron

    2017-04-01

    The central- and peripheral mechanisms by which heat strain limits physical performance are not fully elucidated. Nevertheless, pre-cooling is often used in an attempt to improve subsequent performance. This study compared the effects of pre-cooling vs. a pre-thermoneutral application on central- and peripheral fatigue during 60% of isometric maximum voluntary contraction (MVC) of the right quadriceps femoris muscle. Furthermore, the effects between a pre-cooling and a pre-thermoneutral application on isometric MVC of the right quadriceps femoris muscle and subjective ratings of perceived exertion (RPE) were investigated. In this randomized controlled trial, 18 healthy adults voluntarily participated. The participants received either a cold (experimental) application (+8°C) or a thermoneutral (control) application (+32°C) for 20min on their right thigh (one cuff). After the application, central (fractal dimension - FD) and peripheral (muscle fiber conduction velocity - CV) fatigue was estimated using sEMG parameters during 60% of isometric MVC. Surface EMG signals were detected from the vastus medialis and lateralis using bidimensional arrays. Immediately after the submaximal contraction, isometric MVC and RPE were assessed. Participants receiving the cold application were able to maintain a 60% isometric MVC significantly longer when compared to the thermoneutral group (mean time: 78 vs. 46s; p=0.04). The thermoneutral application had no significant impact on central fatigue (p>0.05) compared to the cold application (p=0.03). However, signs of peripheral fatigue were significantly higher in the cold group compared to the thermoneutral group (p=0.008). Pre-cooling had no effect on isometric MVC of the right quadriceps muscle and ratings of perceived exertion. Pre-cooling attenuated central fatigue and led to significantly longer submaximal contraction times compared to the pre-thermoneutral application. These findings support the use of pre-cooling procedures

  5. Artificial oxygen transport protein

    Science.gov (United States)

    Dutton, P. Leslie

    2014-09-30

    This invention provides heme-containing peptides capable of binding molecular oxygen at room temperature. These compounds may be useful in the absorption of molecular oxygen from molecular oxygen-containing atmospheres. Also included in the invention are methods for treating an oxygen transport deficiency in a mammal.

  6. Consumo de oxigênio pós-exercícios de força e aeróbio: efeito da ordem de execução Strength and aerobic post-exercises oxygen consumption: effect of the order of performance

    Directory of Open Access Journals (Sweden)

    Fábio Santos de Lira

    2007-12-01

    do EPOC é bastante reduzido (≅ 15kcal.Concurrent training is a strategy which has been used with the purpose to maximize energy expenditure both during and after exercise by exacerbation of excess post-exercise oxygen consumption (EPOC. However, little is known about the influence of the order of performance of exercises on EPOC. The aim of the present study was to verify the influence of type (aerobic, strength and concurrent and order (aerobic + strength or strength + aerobic of exercise on excessive post-exercise oxygen consumption. Eight male volunteers (age: 24 ± 2 years; weight mass: 75.4 ± 3.7 kg; and height: 179 ± 3.0 cm, with experience in aerobic and strength training were studied. The subjects were submitted to a test for the determination of the VO2peak (57.0 ± 2.9 ml/kg/min and test of 1-RM for the exercises of bench press (68 ± 2 kg, lat pull down (64 ± 3 kg, leg extension (51 ± 3 kg and leg curl (38 ± 3 kg. Aerobic training was conducted for 30 minutes at 90% of the anaerobic threshold velocity (10.3 ± 2.2 km. The protocol strength training corresponded to 70% of 1RM, divided in three sets of 12 repetitions. Oxygen consumption (VO2 was measured at rest (R and after the following sessions: aerobic (A, strength (S, aerobic-strength (A + S and strength-aerobic (S + A, using indirect calorimetry for 30 minutes, which were divided in three time intervals: T1 (0-10 minutes, T2 (11-20 minutes and T3 (the 21-30 minutes. The comparison of the VO2 among the different situations (R, A, S, A + S and S + A for each period of time (0-10, 11-20; 21-30 min was determined by one-way ANOVA with repeated measurements, followed by Tukey test. In T1, the VO2 of the different sessions was increased in relation to R. During T2, the VO2 of situations S, A + S and S + A was increased in relation to R. In T3, only A + S resulted in EPOC. The results indicate that exercise order influences EPOC time. However, in 30 minutes the caloric expenditure caused by EPOC was

  7. Magnetic resonance and diffusion tensor imaging analyses indicate heterogeneous strains along human medial gastrocnemius fascicles caused by submaximal plantar-flexion activity.

    Science.gov (United States)

    Karakuzu, Agah; Pamuk, Uluç; Ozturk, Cengizhan; Acar, Burak; Yucesoy, Can A

    2017-05-24

    Sarcomere length changes are central to force production and excursion of skeletal muscle. Previous modeling indicates non-uniformity of that if mechanical interaction of muscle with its surrounding muscular and connective tissues is taken into account. Hence, quantifying length changes along the fascicles of activated human muscle in vivo is crucial, but this is lacking due to technical complexities. Combining magnetic resonance imaging deformation analyses and diffusion tensor imaging tractography, the aim was to test the hypothesis that submaximal plantar flexion activity at 15% MVC causes heterogeneous length changes along the fascicles of human medial gastrocnemius (GM) muscle. A general fascicle strain distribution pattern shown for all subjects indicates that proximal track segments are shortened, whereas distal ones are lengthened (e.g., by 13% and 29%, respectively). Mean fiber direction strains of different tracts also shows heterogeneity (for up to 57.5% of the fascicles). Inter-subject variability of amplitude and distribution of fascicle strains is notable. These findings confirm the hypothesis and are solid indicators for the functionally dependent mechanics of human muscle, in vivo. Heterogeneity of fascicle strains can be explained by epimuscular myofascial force transmission. To the best of our knowledge, this is the first study, which quantified local deformations along human skeletal muscle fascicles caused by sustained submaximal activation. The present approach and indicated fascicle strain heterogeneity has numerous implications for muscle function in health and disease to estimate the muscle's contribution to the joint moment and excursion and to evaluate mechanisms of muscle injury and several treatment techniques. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. [birthweight And Caffeine Consumption].

    OpenAIRE

    Bicalho, Gladys Gripp; Barros Filho, Antônio de Azevedo

    2015-01-01

    To assess the association between maternal caffeine consumption during pregnancy and low birth weight, prematurity and intrauterine growth retardation. A case-control was carried out and 354 newborns of single labor with birthweight 3,000 g (controls) were analyzed. Caffeine consumption was calculated based on daily consumption of coffee, soft drinks and tea. Results were adjusted using multiple logistic regression for the following confounders: mother's age, schooling, income, marital status...

  9. Alcohol Consumption in Students

    OpenAIRE

    Tran, Cathy

    2010-01-01

    Drinking behaviour among university students is a serious public health concern. Reasons for drinking are complex and many factors contribute to this behaviour. Previous research has established links between personality factors and alcohol consumption and also between metacognitions and alcohol consumption. Few studies have looked into how personality traits and metacognitions interact. This study investigated the relationships between personality, metacognitions and alcohol consumption in a...

  10. Water consumption in Iron Age, Roman, and Early Medieval Croatia.

    Science.gov (United States)

    Lightfoot, E; Slaus, M; O'Connell, T C

    2014-08-01

    Patterns of water consumption by past human populations are rarely considered, yet drinking behavior is socially mediated and access to water sources is often socially controlled. Oxygen isotope analysis of archeological human remains is commonly used to identify migrants in the archeological record, but it can also be used to consider water itself, as this technique documents water consumption rather than migration directly. Here, we report an oxygen isotope study of humans and animals from coastal regions of Croatia in the Iron Age, Roman, and Early Medieval periods. The results show that while faunal values have little diachronic variation, the human data vary through time, and there are wide ranges of values within each period. Our interpretation is that this is not solely a result of mobility, but that human behavior can and did lead to human oxygen isotope ratios that are different from that expected from consumption of local precipitation. © 2014 Wiley Periodicals, Inc.

  11. Oxygen gradients in tissue-engineered PEGT/PBT cartilaginous constructs: Measurement and modeling

    NARCIS (Netherlands)

    Malda, J.; Rouwkema, Jeroen; Martens, D.E.; le Comte, EP; Kooy, F.K.; Tramper, J.; van Blitterswijk, Clemens; Riesle, J.U.

    2004-01-01

    The supply of oxygen within three-dimensional tissue-engineered (TE) cartilage polymer constructs is mainly by diffusion. Oxygen consumption by cells results in gradients in the oxygen concentration. The aims of this study were, firstly, to identify the gradients within TE cartilage polymer

  12. Oxygen gradients in tissue-engineered PEGT/PBT cartilaginous constructs: measurement and modeling

    NARCIS (Netherlands)

    Malda, J.; Rouwkema, J.; Martens, D.E.; Paul le Comte, E.; Kooy, F.K.; Tramper, J.; Blitterswijk, van C.A.; Riesle, J.

    2004-01-01

    The supply of oxygen within three-dimensional tissue-engineered (TE) cartilage polymer constructs is mainly by diffusion. Oxygen consumption by cells results in gradients in the oxygen concentration. The aims of this study were, firstly, to identify the gradients within TE: cartilage polymer

  13. Consumption and the Consumer

    Directory of Open Access Journals (Sweden)

    Maria VADUVA

    2016-09-01

    Full Text Available The consumer is that trader responsible for consumption act of some final goods or services who decided what must be produce and in what cantity, being the one who make the economic mechanism to move. Consumption is in close connection with the production of goods and services, exerting an active role, any activity should be complete by consuming its results; consumption creates the motivation to achieve economic and non-economic activities. The traditional approach to consumer behavior starts from hypothesised that all consumers seek to maximize the aggregate utility obtained of satisfactions resulting from consumption of goods taking into account the budgetary constraints given by income that consumer has and the prices of these goods. In the conditions of modern economy, consumption can be increased by diseconomies. If consumption depends on permanent income, revenue growth effectively does not exert influence on consumption only to the extent that this increase of income leads to increasing permanent income consumer. Consumption is viewed as an active agent of economic life, it is not only a consumer of goods and services but also a producer.

  14. Experience and Sustainable Consumption

    DEFF Research Database (Denmark)

    Rasmussen, Tove Arendt

    consumption may re-enchant ordinary consumption and thereby even become a part of marketing and the experience economy. New layers of meaning are at stake and altruistic motives come into play; doing something good for someone or something, aside from oneself, is a very strong trigger of positive emotions...

  15. Experience and Sustainable Consumption

    DEFF Research Database (Denmark)

    Rasmussen, Tove Arendt

    2014-01-01

    consumption may re-enchant ordinary consumption and thereby even become a part of marketing and the experience economy. New layers of meaning are at stake and altruistic motives come into play; doing something good for someone or something, aside from oneself, is a very strong trigger of positive emotions...

  16. Value Creation and Consumption

    DEFF Research Database (Denmark)

    Taillard, Marie; Voyer, Benjamin; Glaveanu, Vlad Petre

    2014-01-01

    An effect of the digital economy has been to provide consumers with almost unlimited ways to customize their consumption activities. They can craft each consumption experience to fit specific contexts, needs, emotions and other factors. A teenager’s night out is documented and shared with her...

  17. The influence of systemic hemodynamics and oxygen transport on cerebral oxygen saturation in neonates after the Norwood procedure.

    Science.gov (United States)

    Li, Jia; Zhang, Gencheng; Holtby, Helen; Guerguerian, Anne-Marie; Cai, Sally; Humpl, Tilman; Caldarone, Christopher A; Redington, Andrew N; Van Arsdell, Glen S

    2008-01-01

    Ischemic brain injury is an important morbidity in neonates after the Norwood procedure. Its relationship to systemic hemodynamic oxygen transport is poorly understood. Sixteen neonates undergoing the Norwood procedure were studied. Continuous cerebral oxygen saturation was measured by near-infrared spectroscopy. Continuous oxygen consumption was measured by respiratory mass spectrometry. Pulmonary and systemic blood flow, systemic vascular resistance, oxygen delivery, and oxygen extraction ratio were derived with measurements of arterial, and superior vena cava and pulmonary venous gases and pressures at 2- to 4-hour intervals during the first 72 hours in the intensive care unit. Mean cerebral oxygen saturation was 66% +/- 12% before the operation, reduced to 51% +/- 13% on arrival in the intensive care unit, and remained low during the first 8 hours; it increased to 56% +/- 9% at 72 hours, still significantly lower than the preoperative level (P blood flow and oxygen delivery (P blood flow (P = .001) and hemoglobin (P = .02) and negatively correlated with systemic vascular resistance (P = .003). It was not correlated with oxygen consumption (P > .05). Cerebral oxygen saturation decreased significantly in neonates during the early postoperative period after the Norwood procedure and was significantly influenced by systemic hemodynamic and metabolic events. As such, hemodynamic interventions to modify systemic oxygen transport may provide further opportunities to reduce the risk of cerebral ischemia and improve neurodevelopmental outcomes.

  18. Oxygen Consumption Ratio - Reduction in Energy Consumption Using Moving Bed Biofilter

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Land-based reuse systems offer many advantages over netpens or flow-through systems. This includes reduced siting problems, better control of water quality, and...

  19. Microsensor and transcriptomic signatures of oxygen depletion in biofilms associated with chronic wounds: Biofilms and oxygen

    Energy Technology Data Exchange (ETDEWEB)

    James, Garth A. [Center for Biofilm Engineering, Montana State University, Bozeman Montana; Ge Zhao, Alice [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Usui, Marcia [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Underwood, Robert A. [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Nguyen, Hung [The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman Washington; Beyenal, Haluk [The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman Washington; deLancey Pulcini, Elinor [Center for Biofilm Engineering, Montana State University, Bozeman Montana; Agostinho Hunt, Alessandra [Department of Microbiology and Molecular Genetics, 5180 Biomedical and Physical Sciences, Michigan State University, East Lansing Michigan; Bernstein, Hans C. [Pacific Northwest National Laboratory, Chemical and Biological Signature Science, Richland Washington; Fleckman, Philip [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Olerud, John [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Williamson, Kerry S. [Center for Biofilm Engineering, Montana State University, Bozeman Montana; Franklin, Michael J. [Center for Biofilm Engineering, Montana State University, Bozeman Montana; Stewart, Philip S. [Center for Biofilm Engineering, Montana State University, Bozeman Montana

    2016-02-16

    Polymicrobial biofilms have been implicated in delayed wound healing, although the mechanisms by which biofilms impair wound healing are poorly understood. Many species of bacteria produce exotoxins and exoenzymes that may inhibit healing. In addition, oxygen consumption by biofilms may impede wound healing. In this study, we used oxygen microsensors to measure oxygen transects through in vitro-cultured biofilms, biofilms formed in vivo in a diabetic (db/db) mouse model, and ex vivo human chronic wound specimens. The results show that oxygen levels within both euthanized and live mouse wounds had steep gradients that reached minima ranging from 19 to 61% oxygen partial pressure, compared to atmospheric oxygen levels. The oxygen gradients in the mouse wounds were similar to those observed for clinical isolates cultured in vitro and for human ex vivo scabs. No oxygen gradients were observed for heat-killed scabs, suggesting that active metabolism by the viable bacteria contributed to the reduced oxygen partial pressure of the wounds. To characterize the metabolic activities of the bacteria in the mouse wounds, we performed transcriptomics analyses of Pseudomonas aeruginosa biofilms associated with the db/db mice wounds using Affymetrix microarrays. The results demonstrated that the bacteria expressed genes for metabolic activities associated with cell growth. Interestingly, the transcriptome results indicated that the bacteria within the wounds also experienced oxygen-limitation stress. Among the bacterial genes that were expressed in vivo were genes associated with the Anr-mediated hypoxia-stress response. Other bacterial stress response genes highly expressed in vivo were genes associated with stationary-phase growth, osmotic stress, and RpoH-mediated heat shock stress. Overall, the results support the hypothesis that the metabolic activities of bacteria in biofilms act as oxygen sinks in chronic wounds and that the depletion of oxygen contributes to the

  20. Serum Tumor Necrosis Factor-alpha associates with Myocardial Oxygen Demand and Exercise Tolerance in Postmenopausal Women.

    Science.gov (United States)

    Carter, Stephen J; Bryan, David R; Neumeier, William H; Glasser, Stephen P; Hunter, Gary R

    2018-01-01

    The functional implications of serum tumor necrosis factor-alpha (TNF-α), a marker of oxidative stress, on hemodynamic parameters at rest and during physical exertion are unclear. The aims of this investigation were to examine the independent associations of TNF-α on myocardial oxygen demand at rest and during submaximal exercise, while also evaluating the association of TNF-α on exercise tolerance. Forty, postmenopausal women, provided blood samples and completed a modified-Balke protocol to measure maximal oxygen uptake (VO 2max ). Large artery compliance was measured by pulse contour analyses while rate-pressure product (RPP), an index of myocardial oxygen demand, was measured at rest and during two submaximal workloads (i.e., ≈55% and ≈75% VO 2max ). RPP was calculated by dividing the product of heart rate and systolic blood pressure (via auscultation) by 100. Exercise tolerance corresponded with the cessation of the graded exercise test. During higher-intensity exertion, ≈75% VO 2max , multiple linear regression revealed a positive association ( r = 0.43; p = 0.015) between TNF-α and RPP while adjusting for maximal heart rate, VO 2max , large artery compliance, and percent body fat. Path analyses revealed a significant indirect effect of large artery compliance on exercise tolerance through TNF-α, β = 0.13, CI [0.03, 0.35], indicating greater levels of TNF-α associated with poorer exercise tolerance. These data suggest TNF-α independently associates with myocardial oxygen demand during physical exertion, thus highlighting the utility of higher-intensity efforts to expose important phenomena not apparent at rest. TNF-α also appears to be indirectly associated with the link between large artery compliance and exercise tolerance.

  1. Effect of chain wheel shape on crank torque, freely chosen pedal rate, and physiological responses during submaximal cycling

    DEFF Research Database (Denmark)

    Hansen, Ernst Albin; Jensen, Kurt; Hallen, Jostein

    2009-01-01

    at preset pedal rates as well as resulting in lower pedal rate and metabolic response at freely chosen pedal rate. Ten trained cyclists (mean+/-SD: 27+/-3 years of age, 182+/-4 cm tall, 77.5+/-7.0 kg of body mass, and peak oxygen uptake of 61.7+/-4.4 ml kg(-1) min(-1)) cycled with a Biopace and a circular...... chain wheel at 180 W at 65 and 90 rpm for recording of crank torque profiles, and at their freely chosen pedal rate for recording of pedal rate and metabolic response, including oxygen uptake and blood lactate concentration. Crank torque profiles were similar between the two chain wheels during cycling...... at preset pedal rates. During cycling at the freely chosen pedal rate (being 93+/-6 and 93+/-4 rpm for the Biopace and circular chain wheel, respectively), blood lactate concentration was significantly different between the two chain wheels, being on average 0.2 mmol l(-1) lower with the Biopace chain wheel...

  2. Biogeochemistry: Oxygen burrowed away

    NARCIS (Netherlands)

    Meysman, F.J.R.

    2014-01-01

    Multicellular animals probably evolved at the seafloor after a rise in oceanic oxygen levels. Biogeochemical model simulations suggest that as these animals started to rework the seafloor, they triggered a negative feedback that reduced global oxygen.

  3. Oxygen transport membrane

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a novel composite oxygen transport membrane as well as its preparation and uses thereof.......The present invention relates to a novel composite oxygen transport membrane as well as its preparation and uses thereof....

  4. Proterozoic atmospheric oxygen

    DEFF Research Database (Denmark)

    Canfield, Donald Eugene

    2014-01-01

    This article is concerned with the evolution of atmospheric oxygen concentrations through the Proterozoic Eon. In particular, this article will seek to place the history of atmospheric oxygenation through the Proterozoic Eon in the context of the evolving physical environment including the history...... of continental growth and volcanic outgassing, as well as biogeochemical processing of elements within the oceans. The author will seek to explore constraints on the history of oxygenation and understand which processes have regulated oxygen through this eon....

  5. Oxygen evolution reaction catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Haber, Joel A.; Jin, Jian; Xiang, Chengxiang; Gregoire, John M.; Jones, Ryan J.; Guevarra, Dan W.; Shinde, Aniketa A.

    2016-09-06

    An Oxygen Evolution Reaction (OER) catalyst includes a metal oxide that includes oxygen, cerium, and one or more second metals. In some instances, the cerium is 10 to 80 molar % of the metals in the metal oxide and/or the catalyst includes two or more second metals. The OER catalyst can be included in or on an electrode. The electrode can be arranged in an oxygen evolution system such that the Oxygen Evolution Reaction occurs at the electrode.

  6. Bat consumption in Thailand

    Directory of Open Access Journals (Sweden)

    Kanokwan Suwannarong

    2016-01-01

    Full Text Available Background: Human consumption of bats poses an increasing public health threat globally. Communities in which bat guano is mined from caves have extensive exposure to bat excreta, often harvest bats for consumption, and are at risk for bat-borne diseases. Methods: This rapid ethnographic study was conducted in four provinces of Thailand (Ratchaburi, Sakaeo, Nakorn Sawan, and Phitsanulok, where bat guano was mined and sold during the period April–August 2014. The aim of this study was to understand behaviors and risk perceptions associated with bat conservation, exposure to bats and their excreta, and bat consumption. Sixty-seven respondents playing various roles in bat guano mining, packaging, sale, and use as fertilizer participated in the study. Data were collected through interviews and/or focus group discussions. Results: In spite of a bat conservation program dating back to the 1980s, the benefits of conserving bats and the risks associated with bat consumption were not clear and infrequently articulated by study respondents. Discussion: Since bat consumption continues, albeit covertly, the risk of bat-borne diseases remains high. There is an opportunity to reduce the risk of bat-borne diseases in guano-mining communities by strengthening bat conservation efforts and raising awareness of the health risks of bat consumption. Further research is suggested to test behavior change strategies for reducing bat consumption.

  7. Bat consumption in Thailand.

    Science.gov (United States)

    Suwannarong, Kanokwan; Schuler, Sidney

    2016-01-01

    Human consumption of bats poses an increasing public health threat globally. Communities in which bat guano is mined from caves have extensive exposure to bat excreta, often harvest bats for consumption, and are at risk for bat-borne diseases. This rapid ethnographic study was conducted in four provinces of Thailand (Ratchaburi, Sakaeo, Nakorn Sawan, and Phitsanulok), where bat guano was mined and sold during the period April-August 2014. The aim of this study was to understand behaviors and risk perceptions associated with bat conservation, exposure to bats and their excreta, and bat consumption. Sixty-seven respondents playing various roles in bat guano mining, packaging, sale, and use as fertilizer participated in the study. Data were collected through interviews and/or focus group discussions. In spite of a bat conservation program dating back to the 1980s, the benefits of conserving bats and the risks associated with bat consumption were not clear and infrequently articulated by study respondents. Since bat consumption continues, albeit covertly, the risk of bat-borne diseases remains high. There is an opportunity to reduce the risk of bat-borne diseases in guano-mining communities by strengthening bat conservation efforts and raising awareness of the health risks of bat consumption. Further research is suggested to test behavior change strategies for reducing bat consumption.

  8. [Domiciliary oxygen therapy].

    Science.gov (United States)

    Abdel Kafi, S

    2010-09-01

    In Belgium, oxygen therapy is becoming more and more accessible. When oxygen is needed for short periods or for special indications as palliative care, an agreement between mutual insurance companies and pharmacists allows the practitioner the home installation of gazeous oxygen cylinder or of oxygen concentrator. When long term oxygen therapy (LTOT) is indicated for patients with respiratory insufficiency, the pneumologist must first ask the INAMI the authorization to install one of the following modalities: oxygen concentrator with or without demand oxygen delivery cylinder and liquid oxygen. The goal of LTOT is to increase survival and quality of life. The principal and well accepted indication for LTOT is severe hypoxemia. The beneficial effects of oxygen therapy limited at night or on exertion are controversial. In order to increase patient's autonomy, oxygen can be prescribed for ambulation, respecting prescription's rules. At each step of oxygen therapy implementing (indication, choice of the device and follow-up) the patient under oxygen may benefit from a joint approach between the general practitioner and the chest specialist.

  9. Aircraft Oxygen Generation

    Science.gov (United States)

    2012-02-01

    An Oxygen Enriched Air System for the AV-8A Harrier (NADC-81198-60).” 70 Horch , T., et. al. “The F-16 Onboard Oxygen Generating System: Performance...Only and Safety Privileged). Horch , T., Miller, R., Bomar, J., Tedor, J., Holden, R., Ikels, K., & Lozano, P. (1983). The F-16 Onboard Oxygen

  10. Marriage and Consumption

    DEFF Research Database (Denmark)

    Blow, Laura; Browning, Martin; Ejrnæs, Mette

    We examine theoretically and empirically consumption over the early part of the life-cycle. The main focus is on the transition from being single to living with someone else. Our theoretical model allows for publicness in consumption; uncertainty concerning marriage; differences between lifetime...... incomes for prospective partners and a marriage premium. We develop a two period model to bring out the main features of the impact of marriage on consumption and saving. We then develop a multi-period model that can be taken to the data on expenditures by singles and couples aged between 18 and 30. Our...

  11. Electromyographic, cerebral and muscle hemodynamic responses during intermittent, isometric contractions of the biceps brachii at three submaximal intensities

    Directory of Open Access Journals (Sweden)

    Yagesh eBhambhani

    2014-06-01

    Full Text Available This study examined the electromyographic, cerebral and muscle hemodynamic responses during intermittent isometric contractions of biceps brachii at 20%, 40% and 60% of maximal voluntary contraction (MVC. Eleven volunteers completed two minutes of intermittent isometric contractions (12/min at an elbow angle of 90° interspersed with three minutes rest between intensities in systematic order. Surface electromyography (EMG was recorded from the right biceps brachii and near infrared spectroscopy (NIRS was used to simultaneously measure left prefrontal and right biceps brachii oxyhemoglobin (HbO2, deoxyhemoglobin (HHb and total hemoglobin (Hbtot. Transcranial Doppler ultrasound was used to measure middle cerebral artery velocity (MCAv bilaterally. Finger photoplethysmography was used to record beat-to-beat blood pressure and heart rate. EMG increased with force output from 20% to 60% MVC (P0.05. MCAv increased from rest to exercise but was not different among intensities (P>0.05. Force output correlated with the root mean square EMG and changes in muscle HbO2 (P0.05 at all three intensities. Force output declined by 8% from the 1st to the 24th contraction only at 60% MVC and was accompanied by systematic increases in RMS, cerebral HbO2 and Hbtot with a levelling off in muscle HbO2 and Hbtot. These changes were independent of alterations in mean arterial pressure. Since cerebral blood flow and oxygenation were elevated at 60% MVC, we attribute the development of fatigue to reduced muscle oxygen availability rather than impaired central n

  12. Oxygen configurations in silica

    International Nuclear Information System (INIS)

    Chelikowsky, James R.; Chadi, D. J.; Binggeli, N.

    2000-01-01

    We propose a transition state for oxygen in silica. This state is produced by the insertion of an oxygen molecule into the Si-O-Si bond, i.e., it consists of producing a Si-O-O-O-Si bond. This state allows molecular oxygen diffusion in silica without breaking the molecular O 2 bond and it is energetically more stable than a peroxy configuration. This configuration may allow for exchange of molecular oxygen with the oxygen in the silica framework. (c) 2000 The American Physical Society

  13. Interactive energy consumption visualization

    CSIR Research Space (South Africa)

    Lunga, D

    2014-11-01

    Full Text Available in an office building environment. The main goal is to highlight high consumptions patterns, estimate costs and savings, and recommend energy saving strategies. In its useful nature, the dashboard can provide valuable information for further programs tied...

  14. Emotions and consumption behaviour

    OpenAIRE

    I. Soscia

    2013-01-01

    This stimulating book scrutinizes how emotions function in consumers, from both a psychological and a managerial perspective. It demonstrates how gratitude, happiness, guilt, anger, pride and sadness determine different post-consumption behaviours such as positive and negative word of mouth, repurchase intention and complaint behaviour. The emotional side of consumption seems to play an essential role in explaining choices made and actions taken by consumers. Isabella Soscia explores the ...

  15. Carbon offsetting: sustaining consumption?

    OpenAIRE

    Heather Lovell; Harriet Bulkeley; Diana Liverman

    2009-01-01

    In this paper we examine how theories of sustainable and ethical consumption help us to understand a new, rapidly expanding type of consumer product designed to mitigate climate change: carbon offsets. The voluntary carbon offset market grew by 200% between 2005 and 2006, and there are now over 150 retailers of voluntary carbon offsets worldwide. Our analysis concentrates on the production and consumption of carbon offsets, drawing on ideas from governmentality and political ecology about how...

  16. Changes in cultural consumption

    DEFF Research Database (Denmark)

    Navarrete, T.; Borowiecki, K. J.

    2016-01-01

    Visits to museums have been studied as hedonic and utilitarian forms of cultural consumption, though limited attention has been given to the access of museum collections online. We perform a unique historic analysis of the visibility of collections in a museum of ethnographic collections and comp......, particularly when showing them being used). Results support understanding of online heritage consumption and emerging dynamics, particularly outside of an institutional environment, such as Wikipedia. © 2016 Informa UK Limited, trading as Taylor & Francis Group....

  17. Consumption and Children

    DEFF Research Database (Denmark)

    Browning, Martin; Ejrnæs, Mette

    2009-01-01

    supply. We develop two tests of the extreme hypothesis that only changes in family structure matter. We estimate effects of the numbers and ages of children on consumption. These estimates allow us to rationalize all of the increase in consumption without recourse to any of the causal mechanisms. Our...... estimates can be interpreted either as giving upper bounds on the effects of children or as evidence that the other causes are not important....

  18. Economic theories of sustainable consumption

    NARCIS (Netherlands)

    Ferrer-i-Carbonell, Ada; Bergh, van den Jeroen C.J.M.

    1999-01-01

    The term `sustainable consumption' denotes the search for consumption patterns that reduce human pressure on the environment and nature. This searchinvolves three levels of research. First, the relationship between consumption, lifestyles and environmental sustainability has to be clarified.

  19. Effects of Fiber Type and Size on the Heterogeneity of Oxygen Distribution in Exercising Skeletal Muscle

    Science.gov (United States)

    Liu, Gang; Mac Gabhann, Feilim; Popel, Aleksander S.

    2012-01-01

    The process of oxygen delivery from capillary to muscle fiber is essential for a tissue with variable oxygen demand, such as skeletal muscle. Oxygen distribution in exercising skeletal muscle is regulated by convective oxygen transport in the blood vessels, oxygen diffusion and consumption in the tissue. Spatial heterogeneities in oxygen supply, such as microvascular architecture and hemodynamic variables, had been observed experimentally and their marked effects on oxygen exchange had been confirmed using mathematical models. In this study, we investigate the effects of heterogeneities in oxygen demand on tissue oxygenation distribution using a multiscale oxygen transport model. Muscles are composed of different ratios of the various fiber types. Each fiber type has characteristic values of several parameters, including fiber size, oxygen consumption, myoglobin concentration, and oxygen diffusivity. Using experimentally measured parameters for different fiber types and applying them to the rat extensor digitorum longus muscle, we evaluated the effects of heterogeneous fiber size and fiber type properties on the oxygen distribution profile. Our simulation results suggest a marked increase in spatial heterogeneity of oxygen due to fiber size distribution in a mixed muscle. Our simulations also suggest that the combined effects of fiber type properties, except size, do not contribute significantly to the tissue oxygen spatial heterogeneity. However, the incorporation of the difference in oxygen consumption rates of different fiber types alone causes higher oxygen heterogeneity compared to control cases with uniform fiber properties. In contrast, incorporating variation in other fiber type-specific properties, such as myoglobin concentration, causes little change in spatial tissue oxygenation profiles. PMID:23028531

  20. Reduced oxygen enhancement ratio at low doses

    International Nuclear Information System (INIS)

    Palcic, B.; Skarsgard, L.D.

    1984-01-01

    The oxygen depletion rate in cell suspensions was measured using a Clark electrode. It was found that under experimental conditions used in this laboratory for hypoxic irradiations, the oxygen levels before the start of irradiation are always below 0.1μm, the levels which could give any significant enhancement to radiation inactivation by x-rays. The measured O/sub 2/ depletion rates were comparable to those reported in the literature. Chinese hamster cells (CHO) were made hypoxic by gas exchange, combined with metabolic consumption of oxygen by cells at 37 0 C. Full survival curves were determined in the dose range 0 to 3Gy using the low dose survival assay. The results confirmed the authors' earlier finding that the OER decreases at low doses. The authors therefore believe that the dose-dependent OER is a true radiobiological phenomenon and not an artifact of the experimental method used in the low dose survival assay