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Sample records for oxygen uptake vo2peak

  1. 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.

  2. Allometric modelling of peak oxygen uptake in male soccer players of 8-18 years of age

    NARCIS (Netherlands)

    Valente-dos-Santos, Joao; Coelho-e-Silva, Manuel J.; Tavares, Oscar M.; Brito, Joao; Seabra, Andre; Rebelo, Antonio; Sherar, Lauren B.; Elferink-Gemser, Marije T.; Malina, Robert M.

    Background: Peak oxygen uptake (VO2peak) is routinely scaled as mL O-2 per kilogram body mass despite theoretical and statistical limitations of using ratios. Aim: To examine the contribution of maturity status and body size descriptors to ageassociated inter-individual variability in VO2peak and to

  3. Changes in Peak Oxygen Uptake and Plasma Volume in Fit and Unfit Subjects Following Exposure to a Simulation of Microgravity

    National Research Council Canada - National Science Library

    Convertino, Victor

    1997-01-01

    To test the hypothesis that the magnitude of reduction in plasma volume and work capacity following exposure to simulated microgravity is dependent on the initial level of aerobic fitness, peak oxygen uptake (VO2peak...

  4. A prospective population study of resting heart rate and peak oxygen uptake (the HUNT Study, Norway.

    Directory of Open Access Journals (Sweden)

    Javaid Nauman

    Full Text Available OBJECTIVES: We assessed the prospective association of resting heart rate (RHR at baseline with peak oxygen uptake (VO(2peak 23 years later, and evaluated whether physical activity (PA could modify this association. BACKGROUND: Both RHR and VO(2peak are strong and independent predictors of cardiovascular morbidity and mortality. However, the association of RHR with VO(2peak and modifying effect of PA have not been prospectively assessed in population studies. METHODS: In 807 men and 810 women free from cardiovascular disease both at baseline (1984-86 and follow-up 23 years later, RHR was recorded at both occasions, and VO(2peak was measured by ergospirometry at follow-up. We used Generalized Linear Models to assess the association of baseline RHR with VO(2peak, and to study combined effects of RHR and self-reported PA on later VO(2peak. RESULTS: There was an inverse association of RHR at baseline with VO(2peak (p<0.01. Men and women with baseline RHR greater than 80 bpm had 4.6 mL.kg(-1.min(-1 (95% confidence interval [CI], 2.8 to 6.3 and 1.4 mL.kg(-1.min(-1 (95% CI, -0.4 to 3.1 lower VO(2peak at follow-up compared with men and women with RHR below 60 bpm at baseline. We found a linear association of change in RHR with VO(2peak (p=0.03, suggesting that a decrease in RHR over time is likely to be beneficial for cardiovascular fitness. Participants with low RHR and high PA at baseline had higher VO(2peak than inactive people with relatively high RHR. However, among participants with relatively high RHR and high PA at baseline, VO(2peak was similar to inactive people with relatively low RHR. CONCLUSION: RHR is an important predictor of VO(2peak, and serial assessments of RHR may provide useful and inexpensive information on cardiovascular fitness. The results suggest that high levels of PA may compensate for the lower VO(2peak associated with a high RHR.

  5. 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.

  6. Physical activity as a long-term predictor of peak oxygen uptake: the HUNT Study.

    Science.gov (United States)

    Aspenes, Stian Thoresen; Nauman, Javaid; Nilsen, Tom Ivar Lund; Vatten, Lars Johan; Wisløff, Ulrik

    2011-09-01

    A physically active lifestyle and a relatively high level of cardiorespiratory fitness are important for longevity and long-term health. No population-based study has prospectively assessed the association of physical activity levels with long-term peak oxygen uptake (VO(2peak)). 1843 individuals (906 women and 937 men) who were between 18 and 66 yr at baseline and were free from known lung or heart diseases at both baseline (1984-1986) and follow-up (2006-2008) were included in the study. Self-reported physical activity was recorded at both occasions, and VO(2peak) was measured at follow-up. The association of physical activity levels and VO(2peak) was adjusted for age, level of education, smoking status, and weight change from baseline to follow-up, using ANCOVA statistics. The level of physical activity at baseline was strongly associated with VO(2peak) at follow-up 23 yr later in both men and women (Ptrends active at baseline had higher (3.3 and 4.6 mL·kg(-1)·min(-1)) VO(2peak) at follow-up. Women who were inactive at baseline but highly active at follow-up had 3.7 mL·kg(-1)·min(-1) higher VO(2peak) compared with women who were inactive both at baseline and at follow-up. The corresponding comparison in men showed a difference of 5.2 mL·kg(-1)·min(-1) (95% confidence interval = 3.1-7.3) in VO(2peak). Physical activity level at baseline was positively associated with directly measured cardiorespiratory fitness (VO(2peak)) 23 yr later. People who changed from low to high activity during the observation period had substantially higher V˙O(2peak) at follow-up compared with people whose activity remained low.

  7. Body fat, abdominal fat and body fat distribution related to VO(2PEAK) in young children

    DEFF Research Database (Denmark)

    Dencker, Magnus; Wollmer, Per; Karlsson, Magnus K

    2011-01-01

    as a percentage of body mass (BF%) and body fat distribution as AFM/TBF. VO(2PEAK) was assessed by indirect calorimetry during maximal exercise test. Results. Significant relationships existed between body fat measurements and VO(2PEAK) in both boys and girls, with Pearson correlation coefficients for absolute...

  8. 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.

  9. Predictors of VO2Peak in children age 6- to 7-years-old

    DEFF Research Database (Denmark)

    Dencker, Magnus; Hermansen, Bianca; Bugge, Anna

    2011-01-01

    This study investigated the predictors of aerobic fitness (VO2PEAK) in young children on a population-base. Participants were 436 children (229 boys and 207 girls) aged 6.7 ± 0.4 yrs. VO2PEAK was measured during a maximal treadmill exercise test. Physical activity was assessed by accelerometers....... Total body fat and total fat free mass were estimated from skinfold measurements. Regression analyses indicated that significant predictors for VO2PEAK per kilogram body mass were total body fat, maximal heart rate, sex, and age. Physical activity explained an additional 4-7%. Further analyses showed...... the main contributing factors for absolute values of VO2PEAK were fat free mass, maximal heart rate, sex, and age. Physical activity explained an additional 3-6%....

  10. Peak oxygen uptake in Paralympic sitting sports: A systematic literature review, meta- and pooled-data analysis.

    Science.gov (United States)

    Baumgart, Julia Kathrin; Brurok, Berit; Sandbakk, Øyvind

    2018-01-01

    Peak oxygen uptake (VO2peak) in Paralympic sitting sports athletes represents their maximal ability to deliver energy aerobically in an upper-body mode, with values being influenced by sex, disability-related physiological limitations, sport-specific demands, training status and how they are tested. To identify VO2peak values in Paralympic sitting sports, examine between-sports differences and within-sports variations in VO2peak and determine the influence of sex, age, body-mass, disability and test-mode on VO2peak. Systematic literature review and meta-analysis. PubMed, CINAHL, SPORTDiscusTM and EMBASE were systematically searched in October 2016 using relevant medical subject headings, keywords and a Boolean. Studies that assessed VO2peak values in sitting sports athletes with a disability in a laboratory setting were included. Data was extracted and pooled in the different sports disciplines, weighted by the Dersimonian and Laird random effects approach. Quality of the included studies was assessed with a modified version of the Downs and Black checklist by two independent reviewers. Meta-regression and pooled-data multiple regression analyses were performed to assess the influence of sex, age, body-mass, disability, test mode and study quality on VO2peak. Of 6542 retrieved articles, 57 studies reporting VO2peak values in 14 different sitting sports were included in this review. VO2peak values from 771 athletes were used in the data analysis, of which 30% participated in wheelchair basketball, 27% in wheelchair racing, 15% in wheelchair rugby and the remaining 28% in the 11 other disciplines. Fifty-six percent of the athletes had a spinal cord injury and 87% were men. Sports-discipline-averaged VO2peak values ranged from 2.9 L∙min-1 and 45.6 mL∙kg-1∙min-1 in Nordic sit skiing to 1.4 L∙min-1 and 17.3 mL∙kg-1∙min-1 in shooting and 1.3 L∙min-1 and 18.9 mL∙kg-1∙min-1 in wheelchair rugby. Large within-sports variation was found in sports with few

  11. Peak oxygen uptake in Paralympic sitting sports: A systematic literature review, meta- and pooled-data analysis.

    Directory of Open Access Journals (Sweden)

    Julia Kathrin Baumgart

    Full Text Available Peak oxygen uptake (VO2peak in Paralympic sitting sports athletes represents their maximal ability to deliver energy aerobically in an upper-body mode, with values being influenced by sex, disability-related physiological limitations, sport-specific demands, training status and how they are tested.To identify VO2peak values in Paralympic sitting sports, examine between-sports differences and within-sports variations in VO2peak and determine the influence of sex, age, body-mass, disability and test-mode on VO2peak.Systematic literature review and meta-analysis.PubMed, CINAHL, SPORTDiscusTM and EMBASE were systematically searched in October 2016 using relevant medical subject headings, keywords and a Boolean.Studies that assessed VO2peak values in sitting sports athletes with a disability in a laboratory setting were included.Data was extracted and pooled in the different sports disciplines, weighted by the Dersimonian and Laird random effects approach. Quality of the included studies was assessed with a modified version of the Downs and Black checklist by two independent reviewers. Meta-regression and pooled-data multiple regression analyses were performed to assess the influence of sex, age, body-mass, disability, test mode and study quality on VO2peak.Of 6542 retrieved articles, 57 studies reporting VO2peak values in 14 different sitting sports were included in this review. VO2peak values from 771 athletes were used in the data analysis, of which 30% participated in wheelchair basketball, 27% in wheelchair racing, 15% in wheelchair rugby and the remaining 28% in the 11 other disciplines. Fifty-six percent of the athletes had a spinal cord injury and 87% were men. Sports-discipline-averaged VO2peak values ranged from 2.9 L∙min-1 and 45.6 mL∙kg-1∙min-1 in Nordic sit skiing to 1.4 L∙min-1 and 17.3 mL∙kg-1∙min-1 in shooting and 1.3 L∙min-1 and 18.9 mL∙kg-1∙min-1 in wheelchair rugby. Large within-sports variation was found in

  12. Peak oxygen uptake in Paralympic sitting sports: A systematic literature review, meta- and pooled-data analysis

    Science.gov (United States)

    Brurok, Berit; Sandbakk, Øyvind

    2018-01-01

    Background Peak oxygen uptake (VO2peak) in Paralympic sitting sports athletes represents their maximal ability to deliver energy aerobically in an upper-body mode, with values being influenced by sex, disability-related physiological limitations, sport-specific demands, training status and how they are tested. Objectives To identify VO2peak values in Paralympic sitting sports, examine between-sports differences and within-sports variations in VO2peak and determine the influence of sex, age, body-mass, disability and test-mode on VO2peak. Design Systematic literature review and meta-analysis. Data sources PubMed, CINAHL, SPORTDiscusTM and EMBASE were systematically searched in October 2016 using relevant medical subject headings, keywords and a Boolean. Eligibility criteria Studies that assessed VO2peak values in sitting sports athletes with a disability in a laboratory setting were included. Data synthesis Data was extracted and pooled in the different sports disciplines, weighted by the Dersimonian and Laird random effects approach. Quality of the included studies was assessed with a modified version of the Downs and Black checklist by two independent reviewers. Meta-regression and pooled-data multiple regression analyses were performed to assess the influence of sex, age, body-mass, disability, test mode and study quality on VO2peak. Results Of 6542 retrieved articles, 57 studies reporting VO2peak values in 14 different sitting sports were included in this review. VO2peak values from 771 athletes were used in the data analysis, of which 30% participated in wheelchair basketball, 27% in wheelchair racing, 15% in wheelchair rugby and the remaining 28% in the 11 other disciplines. Fifty-six percent of the athletes had a spinal cord injury and 87% were men. Sports-discipline-averaged VO2peak values ranged from 2.9 L∙min-1 and 45.6 mL∙kg-1∙min-1 in Nordic sit skiing to 1.4 L∙min-1 and 17.3 mL∙kg-1∙min-1 in shooting and 1.3 L∙min-1 and 18.9 mL∙kg-1

  13. Estimation of peak oxygen uptake from maximal power output among 9-10 year-old children in Lhasa, Tibet

    DEFF Research Database (Denmark)

    Bianba, B; Berntsen, S; Andersen, Lars Bo

    2010-01-01

    with the equations from the present study. None of the three could accurately predict the direct measured V.O2peak, and predictions differed in an unsystematic manner, including over- or underestimation and no differentiation between genders. CONCLUSION: Peak oxygen uptake could be estimated from Wmax and sex...

  14. Cardiorespiratory Responses and Prediction of Peak Oxygen Uptake during the Shuttle Walking Test in Healthy Sedentary Adult Men

    Science.gov (United States)

    Neves, Camila D. C.; Lacerda, Ana Cristina Rodrigues; Lage, Vanessa K. S.; Lima, Liliana P.; Fonseca, Sueli F.; de Avelar, Núbia C. P.; Teixeira, Mauro M.; Mendonça, Vanessa A.

    2015-01-01

    Background The application of the Shuttle Walking Test (SWT) to assess cardiorespiratory fitness and the intensity of this test in healthy participants has rarely been studied. This study aimed to assess and correlate the cardiorespiratory responses of the SWT with the cardiopulmonary exercise testing (CEPT) and to develop a regression equation for the prediction of peak oxygen uptake (VO2 peak) in healthy sedentary adult men. Methods In the first stage of this study, 12 participants underwent the SWT and the CEPT on a treadmill. In the second stage, 53 participants underwent the SWT twice. In both phases, the VO2 peak, respiratory exchange ratio (R), and heart rate (HR) were evaluated. Results Similar results in VO2 peak (P>0.05), R peak (P>0.05) and predicted maximum HR (P>0.05) were obtained between the SWT and CEPT. Both tests showed strong and significant correlations of VO2 peak (r = 0.704, P = 0.01) and R peak (r = 0.737, P0.05) was found. Conclusions The SWT produced maximal cardiorespiratory responses comparable to the CEPT, and the developed equation showed viability for the prediction of VO2 peak in healthy sedentary men. PMID:25659094

  15. Do individuals with intellectual disability have a lower peak heart rate and maximal oxygen uptake?

    Science.gov (United States)

    Hilgenkamp, Thessa Irena Maria; Baynard, Tracy

    2017-12-12

    Individuals with intellectual disability (ID) have very low physical activity and low peak oxygen uptake (VO 2peak ), potentially explained by physiologically lower peak heart rates (HR peak ). The present authors performed a retrospective analysis of a large data set of individuals with intellectual disability (n = 100), with Down syndrome (DS) (n = 48) and without intellectual disability (n = 224) using multiple linear regression analyses, to determine if individuals with intellectual disability exhibit lower HR peak and VO 2peak than individuals without intellectual disability, controlling for age, sex and body mass index (BMI). Individuals with intellectual disability on average have significantly lower HR peak and VO 2peak than individuals without intellectual disability, even when controlling VO 2peak for the lower HR peak . This study suggests potential physiological differences in individuals with intellectual disability and warrants further investigation to determine their relevance to physical activity promotion and exercise testing in individuals with intellectual disability. © 2017 John Wiley & Sons Ltd.

  16. Relation of oxygen uptake to work rate in prepubertal healthy children - reference for VO2/W-slope and effect on cardiorespiratory fitness assessment.

    Science.gov (United States)

    Tompuri, Tuomo; Lintu, Niina; Laitinen, Tomi; Lakka, Timo A

    2017-08-09

    Exercise testing by cycle ergometer allows to observe the interaction between oxygen uptake (VO 2 ) and workload (W), and VO 2 /W-slope can be used as a diagnostic tool. Respectively, peak oxygen uptake (VO 2 PEAK ) can be estimated by maximal workload. We aim to determine reference for VO 2 /W-slope among prepubertal children and define agreement between estimated and measured VO 2 PEAK . A total of 38 prepubertal children (20 girls) performed a maximal cycle ergometer test with respiratory gas analysis. VO 2 /W-slopes were computed using linear regression. Agreement analysis by Bland and Altman for estimated and measured VO 2 PEAK was carried out including limits of agreement (LA). Determinants for VO 2 /W-slopes and estimation bias were defined. VO2/W-slope was in both girls and boys ≥9·4 and did not change with exercise level, but the oxygen cost of exercise was higher among physically more active children. Estimated VO 2 PEAK had 6·4% coefficient of variation, and LA varied from 13% underestimation to 13% overestimation. Bias had a trend towards underestimation along lean mass proportional VO 2 PEAK . The primary determinant for estimation bias was VO2/W-slope (β = -0·65; PW-slope among healthy prepubertal children were similar to those published for adults and among adolescents. Estimated and measured VO 2 PEAK should not be considered to be interchangeable because of the variation in the relationship between VO 2 and W. On other hand, variation in the relationship between VO 2 and W enables that VO 2 /W-slope can be used as a diagnostic tool. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  17. COMPARISON OF OXYGEN UPTAKE KINETICS AND OXYGEN DEFICIT IN SEVERELY OVERWEIGHT AND NORMAL WEIGHT ADOLESCENT FEMALES

    Directory of Open Access Journals (Sweden)

    Mark Loftin

    2005-12-01

    Full Text Available The purpose of this study was to determine if differences in oxygen uptake kinetics and oxygen deficit existed between normal weight and severely overweight adolescent girls. Subjects included 10 normal weight and 8 severely overweight girls. The participants performed a leg cycling VO2 peak test and a constant load leg cycling test at 80% of the ventilatory threshold (T-vent. In the constant workload test O2 kinetics as indicated by Phase I (VO2 L at 20 sec and Phase II time constants (t were determined. Also, the O2 deficit (VO2 L was measured. As expected significant differences were noted in body composition and VO2 peak relative to mass with normal weight body mass averaging 55.3 ± 7.0 kg, severely overweight 90.5 ± 18.0 kg, % fat normal weight 27.3 ± 3.9%, severely overweight 49.7 ± 4.9% and VO2 peak (ml·kg-1·min-1 normal weight 32.0 ± 2.7 and severely overweight 22.0 ± 5.3. VO2 peak (l·min-1 and T-vent (%VO2 max were similar between groups. Results revealed similar O2 kinetic responses between groups; phase I kinetics normal weight 0.72 ± 0.15 L; severely overweight 0.75 ± 0.13L, phase II (t normal weight 41.5 ± 21.3 sec; severely overweight 33.9 ± 22.7 sec. However, the O2 deficit was significantly higher in the severely overweight (0.75 ± 0.15L when compared to the normal weight group (0.34 ± 0.13L. Correlations ranged from r = -0.15 to 0.51 between VO2 peak (L·min-1 or fat weight and phase I, t and O2 deficit. These data generally support previous research concerning the independence of O2 uptake response and body size

  18. Heart rate during basketball game play and volleyball drills accurately predicts oxygen uptake and energy expenditure.

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    Scribbans, T D; Berg, K; Narazaki, K; Janssen, I; Gurd, B J

    2015-09-01

    There is currently little information regarding the ability of metabolic prediction equations to accurately predict oxygen uptake and exercise intensity from heart rate (HR) during intermittent sport. The purpose of the present study was to develop and, cross-validate equations appropriate for accurately predicting oxygen cost (VO2) and energy expenditure from HR during intermittent sport participation. Eleven healthy adult males (19.9±1.1yrs) were recruited to establish the relationship between %VO2peak and %HRmax during low-intensity steady state endurance (END), moderate-intensity interval (MOD) and high intensity-interval exercise (HI), as performed on a cycle ergometer. Three equations (END, MOD, and HI) for predicting %VO2peak based on %HRmax were developed. HR and VO2 were directly measured during basketball games (6 male, 20.8±1.0 yrs; 6 female, 20.0±1.3yrs) and volleyball drills (12 female; 20.8±1.0yrs). Comparisons were made between measured and predicted VO2 and energy expenditure using the 3 equations developed and 2 previously published equations. The END and MOD equations accurately predicted VO2 and energy expenditure, while the HI equation underestimated, and the previously published equations systematically overestimated VO2 and energy expenditure. Intermittent sport VO2 and energy expenditure can be accurately predicted from heart rate data using either the END (%VO2peak=%HRmax x 1.008-17.17) or MOD (%VO2peak=%HRmax x 1.2-32) equations. These 2 simple equations provide an accessible and cost-effective method for accurate estimation of exercise intensity and energy expenditure during intermittent sport.

  19. Oscillation of tissue oxygen index in non-exercising muscle during exercise.

    Science.gov (United States)

    Yano, T; Afroundeh, R; Shirakawa, K; Lian, C-S; Shibata, K; Xiao, Z; Yunoki, T

    2015-09-01

    The purpose of the present study was to examine how oscillation of tissue oxygen index (TOI) in non-exercising exercise is affected during high-intensity and low-intensity exercises. Three exercises were performed with exercise intensities of 30% and 70% peak oxygen uptake (Vo(2)peak) for 12 min and with exercise intensity of 70% Vo(2)peak for 30 s. TOI in non-exercising muscle (biceps brachii) during the exercises for 12 min was determined by nearinfrared spectroscopy. TOI in the non-exercising muscle during the exercises was analyzed by fast Fourier transform (FFT) to obtain power spectra density (PSD). The frequency at which maximal PSD appeared (Fmax) during the exercise with 70% Vo(2)peak for 12 min (0.00477 ± 0.00172 Hz) was significantly lower than that during the exercise with 30% Vo2peak for 12 min (0.00781 ± 0.00338 Hz). There were significant differences in blood pH and blood lactate between the exercise with 70% Vo(2)peak and the exercise with 30% Vo(2)peak. It is concluded that TOI in nonexercising muscle oscillates during low-intensity exercise as well as during high-intensity exercise and that the difference in Fmax between the two exercises is associated with the difference in increase in blood lactate derived from the exercise.

  20. Escala de VO2pico em adolescentes obesos e não-Obesos por diferentes métodos Escala de VO2pico en adolescentes obesos y no obesos por diferentes métodos Scale of VO2peak in obese and non-obese adolescents by different methods

    Directory of Open Access Journals (Sweden)

    Gerusa Eisfeld Milano

    2009-12-01

    estrategia atractiva para comparar individuos con grandes diferencias en la masa corporal. OBJETIVO: Investigar el VO2pico en individuos obesos y no obesos usando el método de corrección de masa corporal (convencional y la escala alométrica (método alométrico y cómo esos métodos se aplican cuando individuos de ambos sexos se ejercitan en una cinta ergométrica. MÉTODOS: El VO2pico relativo al peso corporal y por el método alométrico fue comparado en 54 adolescentes obesos y 33 no obesos (10-16 años. Para evaluar el VO2pico durante un test máximo se utilizó calorimetría indirecta. El exponente alométrico fue calculado considerando la masa corporal individual. Así, el VO2pico fue corregido mediante el exponente alométrico. Las comparaciones se realizaron utilizando two-way ANOVA para medidas repetidas (p0,05. Sin embargo, el VO2pico calculado por el método convencional fue mayor (p0.05 entre los grupos. CONCLUSIÓN: Los individuos obesos presentaron VO2pico más bajo que los no obesos, al ser evaluados mediante el método convencional. Sin embargo, las diferencias desaparecieron cuando se aplicó el método de la escala alométrica.BACKGROUND: Peak oxygen uptake (VO2peak can be defined as the highest oxygen rate consumed during exhaustive or maximal exercise. The evaluation of the aerobic fitness can be expressed as relative to body mass, but this procedure may not fully remove differences when heavy subjects are assessed. Thus, the allometric scaling procedure is an attractive strategy to compare individuals with large differences in body mass. OBJECTIVE: Investigate VO2peak in obese and non-obese individuals using body mass correction (conventional and allometric scaling (allometric methods and how these methods apply when subjects of different genders exercise on a treadmill. METHODS: VO2peak relative to body weight and measured by the allometric method were compared in 54 obese and 33 non-obese adolescents (10 a 16 years. Indirect calorimetry was used to

  1. Effect of Aerobic Training on Peak Oxygen Uptake Among Seniors Aged 70 or Older: A Meta-Analysis of Randomized Controlled Trials.

    Science.gov (United States)

    Bouaziz, Walid; Kanagaratnam, Lukshe; Vogel, Thomas; Schmitt, Elise; Dramé, Moustapha; Kaltenbach, Georges; Geny, Bernard; Lang, Pierre Olivier

    2018-01-02

    Older adults undergo a progressive decline in cardiorespiratory fitness and functional capacity. This lower peak oxygen uptake (VO 2peak ) level is associated with increased risk of frailty, dependency, loss of autonomy, and mortality from all causes. Regular physical activity and particularly aerobic training (AT) have been shown to contribute to better and healthy aging. We conducted a meta-analysis to measure the exact benefit of AT on VO 2peak in seniors aged 70 years or older. A comprehensive, systematic database search for articles was performed in Embase, Medline, PubMed Central, Science Direct, Scopus, and Web of Science using key words. Two reviewers independently assessed interventional studies for potential inclusion. Ten randomized controlled trials (RCTs) were included totaling 348 seniors aged 70 years or older. Across the trials, no high risk of bias was measured and all considered open-label arms for controls. With significant heterogeneity between the RCTs (all p seniors were, respectively, 1.72 (95% CI: 0.34-3.10) and 1.47 (95% CI: 0.60-2.34). This meta-analysis confirms the AT-associated benefits on VO 2peak in healthy and unhealthy seniors.

  2. Contraction-mediated glucose uptake is increased in men with impaired glucose tolerance

    DEFF Research Database (Denmark)

    Skov-Jensen, Camilla; Skovbro, Mette; Flint, Anne

    2007-01-01

    stimulation alone and with superimposed exercise. Patients with type 2 diabetes, subjects with impaired glucose tolerance (IGT), healthy controls, and endurance-trained subjects were studied. The groups were matched for age and lean body mass (LBM), and differed in peak oxygen uptake (VO2 peak), body fat...

  3. Arm Crank and Wheelchair Ergometry Produce Similar Peak Oxygen Uptake but Different Work Economy Values in Individuals with Spinal Cord Injury

    Directory of Open Access Journals (Sweden)

    Tom Tørhaug

    2016-01-01

    Full Text Available Objective. To study whether values for peak oxygen uptake (VO2peak and work economy (WE at a standardized workload are different when tested by arm crank ergometry (ACE and wheelchair ergometry (WCE. Methods. Twelve paraplegic men with spinal cord injury (SCI in stable neurological condition participated in this cross-sectional repeated-measures study. We determined VO2peak and peak power output (POpeak values during ACE and WCE in a work-matched protocol. Work economy was tested at a standardized workload of 30 Watts (W for both ACE and WCE. Results. There were no significant differences in VO2peak (mL·kg−1·min−1 between ACE (27.3±3.2 and WCE (27.4±3.8 trials, and a Bland-Altman plot shows that findings are within 95% level of agreement. WE or oxygen consumption at 30 W (VO2-30W was significantly lower during WCE compared to ACE (P<0.039. Mean (95% CI POpeak (W were 130 (111–138 and 100 (83–110 during ACE and WCE, respectively. Conclusion. The findings in the present study support the use of both ACE and WCE for testing peak oxygen uptake. However, WE differed between the two test modalities, meaning that less total energy is used to perform external work of 30 W during wheelchair exercise when using this WCE (VP100 Handisport ergometer. Clinical Trials Protocol Record is NCT00987155/4.2007.2271.

  4. Oxygen uptake response to cycle ergometry in post-acute stroke patients with different severity of hemiparesis.

    Science.gov (United States)

    Chen, Chun-Kai; Weng, Ming-Cheng; Chen, Tien-Wen; Huang, Mao-Hsiung

    2013-11-01

    This study evaluated the impact of severity of hemiparesis on oxygen uptake (VO2) response in post-acute stroke patients. Sixty-four patients with a mean poststroke interval of 8.6 ± 3.8 days underwent a ramp cardiopulmonary exercise test on a cycling ergometer to volitional termination. Mean peak VO2 (VO2peak) and work efficiency (ΔVO2/ΔWR) were measured by open-circuit spirometry during standard upright ergometer cycling. Severity of the hemiparetic lower limb was assessed by Brunnstrom's motor recovery stages lower extremity (BMRSL). VO2peak was 10% lower in hemiparetic leg with BMRSL V than in that with BMRSL VI, 20% lower in BMRSL IV, and 50% lower in BMRSL III. ΔVO2/ΔWR was higher for the group with increased BMRSL. The relations were consistent after adjustment for age, sex, body mass index, stroke type, hemiparetic side, modified Ashworth Scale, time poststroke, comorbidities, and medications. Our findings revealed that O2peak is dependent on the severity of hemiparesis in leg, and along with ΔO2/ΔWR closely related to the severity of hemiparesis in post-acute stroke patients, regardless of the types and locations of lesion after stroke, as well as the differences in comorbidities and medications. Copyright © 2013. Published by Elsevier B.V.

  5. Effect of high-intensity training versus moderate training on peak oxygen uptake and chronotropic response in heart transplant recipients

    DEFF Research Database (Denmark)

    Dall, C H; Snoer, M; Christensen, S

    2014-01-01

    In heart transplant (HTx) recipients, there has been reluctance to recommend high-intensity interval training (HIIT) due to denervation and chronotropic impairment of the heart. We compared the effects of 12 weeks' HIIT versus continued moderate exercise (CON) on exercise capacity and chronotropic...... response in stable HTx recipients >12 months after transplantation in a randomized crossover trial. The study was completed by 16 HTx recipients (mean age 52 years, 75% males). Baseline peak oxygen uptake (VO2peak ) was 22.9 mL/kg/min. HIIT increased VO2peak by 4.9 ± 2.7 mL/min/kg (17%) and CON by 2.6 ± 2.......2 mL/kg/min (10%) (significantly higher in HIIT; p HIIT, systolic blood pressure decreased significantly (p = 0.037) with no significant change in CON (p = 0.241; between group difference p = 0.027). Peak heart rate (HRpeak ) increased significantly by 4.3 beats per minute (p = 0...

  6. High-intensity interval training improves VO2peak, maximal lactate accumulation, time trial and competition performance in 9?11-year-old swimmers

    OpenAIRE

    Sperlich, Billy; Zinner, Christoph; Heilemann, Ilka; Kjendlie, Per-Ludvik; Holmberg, Hans-Christer; Mester, Joachim

    2010-01-01

    Training volume in swimming is usually very high when compared to the relatively short competition time. High-intensity interval training (HIIT) has been demonstrated to improve performance in a relatively short training period. The main purpose of the present study was to examine the effects of a 5-week HIIT versus high-volume training (HVT) in 9?11-year-old swimmers on competition performance, 100 and 2,000?m time (T 100?m and T 2,000?m), VO2peak and rate of maximal lactate accumulation (La...

  7. Força muscular como determinante da eficiência do consumo de oxigênio e da máxima resposta metabólica ao exercício em pacientes com DPOC leve/moderada Muscle strength as a determinant of oxygen uptake efficiency and maximal metabolic response in patients with mild-to-moderate COPD

    Directory of Open Access Journals (Sweden)

    Paulo de Tarso Guerrero Müller

    2012-10-01

    Full Text Available OBJETIVO: Comparar o comportamento de oxygen uptake efficiency slope (OUES, inclinação da eficiência do consumo de oxigênio com o do consumo de oxigênio no pico do exercício (VO2pico. MÉTODOS: Estudo prospectivo transversal envolvendo 21 pacientes (15 homens com DPOC leve/moderada que foram submetidos a espirometria, dinamometria de preensão palmar (DIN, teste cardiopulmonar de exercício e medida de lactato no pico do exercício (LACpico. RESULTADOS: A média de peso foi 66,7 ± 13,6 kg, e a de idade foi 60,7 ± 7,8 anos. Com exceção de VEF1 e relação VEF1/CVF (75,8 ± 18,6 do previsto e 56,6 ± 8,8, respectivamente, as demais variáveis espirométricas foram normais, assim como DIN. As médias, em % do previsto, para VO2pico (93,1 ± 15,4, FC máxima (92,5 ± 10,4 e OUES (99,4 ± 24,4, assim como a da taxa de troca respiratória (1,2 ± 0,1, indicaram estresse metabólico e hemodinâmico importante. A correlação entre o VO2pico e a OUES foi elevada (r = 0,747; p OBJECTIVE: To compare the behavior of the oxygen uptake efficiency slope (OUES with that of oxygen uptake at peak exertion (VO2peak. METHODS: This was a prospective cross-sectional study involving 21 patients (15 men with mild-to-moderate COPD undergoing spirometry, handgrip strength (HGS testing, cardiopulmonary exercise testing, and determination of lactate at peak exertion (LACpeak. RESULTS: Mean weight was 66.7 ± 13.6 kg, and mean age was 60.7 ± 7.8 years. With the exception of FEV1 and FEV1/FVC ratio (75.8 ± 18.6 of predicted and 56.6 ± 8.8, respectively, all spirometric variables were normal, as was HGS. The patients exhibited significant metabolic and hemodynamic stress, as evidenced by the means (% of predicted for VO2peak (93.1 ± 15.4, maximum HR (92.5 ± 10.4, and OUES (99.4 ± 24.4, as well as for the gas exchange rate (1.2 ± 0.1. The correlation between VO2peak and OUES was significant (r = 0.747; p < 0.0001. The correlation between HGS and VO2peak (r

  8. CLA supplementation and aerobic exercise lower blood triacylglycerol, but have no effect on peak oxygen uptake or cardiorespiratory fatigue thresholds.

    Science.gov (United States)

    Jenkins, Nathaniel D M; Buckner, Samuel L; Cochrane, Kristen C; Bergstrom, Haley C; Goldsmith, Jacob A; Weir, Joseph P; Housh, Terry J; Cramer, Joel T

    2014-09-01

    This study examined the effects of 6 weeks of conjugated linoleic acid (CLA) supplementation and moderate aerobic exercise on peak oxygen uptake (VO2 peak), the gas exchange threshold (GET), the respiratory compensation point (RCP), and serum concentrations of cholesterol, triacylglycerol, and glucose in humans. Thirty-four untrained to moderately trained men (mean ± SD; age = 21.5 ± 2.8 years; mass = 77.2 ± 9.5 kg) completed this double-blind, placebo controlled study and were randomly assigned to either a CLA (Clarinol A-80; n = 18) or placebo (PLA; sunflower oil; n = 16) group. Prior to and following 6 weeks of aerobic training (50% VO2 peak for 30 min, twice per week) and supplementation (5.63 g of total CLA isomers [of which 2.67 g was c9, t11 and 2.67 g was t10, c12] or 7.35 g high oleic sunflower oil per day), each participant completed an incremental cycle ergometer test to exhaustion to determine their [Formula: see text] peak, GET, and RCP and fasted blood draws were performed to measure serum concentrations of cholesterol, triacylglycerol, and glucose. Serum triacylglycerol concentrations were lower (p interactions (p 0.05) between the CLA and PLA groups. GET and RCP increased (p < 0.05) from pre- to post-training for both the CLA and PLA groups. Overall, these data suggested that CLA and aerobic exercise may have synergistic, blood triacylglycerol lowering effects, although CLA may be ineffective for enhancing aerobic exercise performance in conjunction with a 6-week aerobic exercise training program in college-age men.

  9. 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.

  10. Insulin resistance and maximal oxygen uptake

    DEFF Research Database (Denmark)

    Seibaek, Marie; Vestergaard, Henrik; Burchardt, Hans

    2003-01-01

    BACKGROUND: Type 2 diabetes, coronary atherosclerosis, and physical fitness all correlate with insulin resistance, but the relative importance of each component is unknown. HYPOTHESIS: This study was undertaken to determine the relationship between insulin resistance, maximal oxygen uptake......, and the presence of either diabetes or ischemic heart disease. METHODS: The study population comprised 33 patients with and without diabetes and ischemic heart disease. Insulin resistance was measured by a hyperinsulinemic euglycemic clamp; maximal oxygen uptake was measured during a bicycle exercise test. RESULTS......: There was a strong correlation between maximal oxygen uptake and insulin-stimulated glucose uptake (r = 0.7, p = 0.001), and maximal oxygen uptake was the only factor of importance for determining insulin sensitivity in a model, which also included the presence of diabetes and ischemic heart disease. CONCLUSION...

  11. Lactate, Glucose and Oxygen Uptake in Human Brain During Recovery from Maximal Exercise

    DEFF Research Database (Denmark)

    Kojiro, I.; Schmalbruch, I.K.; Quistorff, B.

    1999-01-01

    Skeletal muscle, brain lactate uptake, brain oxygen uptake, energy metabolism, brain glucose uptake......Skeletal muscle, brain lactate uptake, brain oxygen uptake, energy metabolism, brain glucose uptake...

  12. Effects of exercise mode on the peak oxygen uptake and blood lactate response in boys aged 11-12 years

    Directory of Open Access Journals (Sweden)

    Fabiana Andrade Machado

    2006-09-01

    Full Text Available The objective of this study was to analyze the effects of exercise mode (running x cycling on the indexesrelated to aerobic fitness (VO2peak and blood lactate response to exercise in children. Participated of this study 20 active boys apparently healthy (age = 11.48 + 0.41 yr.; body mass = 41.38 + 10.45 kg; stature = 147.45 + 6.56 cm, with sexual maturational level 1 and 2 (pubic hair, which performed two incremental tests, with stages of 3 minutes until voluntary exhaustion, in treadmill (TR and cycle ergometer (CE, to the determination of peak oxygen uptake (VO2peak and lactate threshold (LT. The VO2peak was determined through the higher value obtained at intervals of 15 seconds. The LT was determined as the exercise intensity where the first and sustained increase of blood lactate above rest level occurred. The VO2peak (45.16 + 5.98 x 42.93 + 7.51 ml/kg/min, maximal heart rate (196.5 + 6.98 x 187.3 + 9.27 bpm, VO2 at LL (31.82 + 10.09 x 25.19 + 7.36 ml/kg/min and HR at LL (150.5 + 17.75 x 131.3 + 12.98 bpm were significantly higher in TR than CE, respectively. Thus, similar to adults, boys of 11 to 12 years present higher aerobic indexes (submaximal and maximal in running than cycling, which can haveimportant implications for healthy professionals that utilize exercise for the healthy promotion, rehabilitation and experimental designs. RESUMO O objetivo deste estudo foi analisar os efeitos do modo de exercício (corrida x ciclismo sobre os índices relacionados com a aptidão aeróbia (VO2pico e resposta de lactato ao exercício em crianças. Participaram doestudo 20 meninos, aparentemente saudáveis e ativos (idade = 11,48 + 0,41 anos; massa corporal = 41,38 + 10,45 kg; estatura = 147,45 + 6,56 cm, com níveis de maturação sexual 1 e 2 (pilosidade pubiana, que realizaram dois testes incrementais, com estágios de 3 minutos até a exaustão voluntária, em esteira rolante (ER e bicicleta ergométrica (BE, para a determinação do pico do

  13. 21 CFR 868.1730 - Oxygen uptake computer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Oxygen uptake computer. 868.1730 Section 868.1730...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1730 Oxygen uptake computer. (a) Identification. An oxygen uptake computer is a device intended to compute the amount of oxygen consumed by a...

  14. THE CONTRIBUTION OF 'RESTING' BODY MUSCLES TO THE SLOW COMPONENT OF PULMONARY OXYGEN UPTAKE DURING HIGH-INTENSITY CYCLING

    Directory of Open Access Journals (Sweden)

    Susan A. Ward

    2012-12-01

    Full Text Available Oxygen uptake (VO2 kinetics during moderate constant- workrate (WR exercise (>lactate-threshold (ӨL are well described as exponential. AboveӨL, these kinetics are more complex, consequent to the development of a delayed slow component (VO2sc, whose aetiology remains controversial. To assess the extent of the contribution to the VO2sc from arm muscles involved in postural stability during cycling, six healthy subjects completed an incremental cycle-ergometer test to the tolerable limit for estimation of ӨL and determination of peak VO2. They then completed two constant-WR tests at 90% of ӨL and two at 80% of ∆ (difference between ӨL and VO2peak. Gas exchange variables were derived breath-by-breath. Local oxygenation profiles of the vastus lateralis and biceps brachii muscles were assessed by near-infrared spectroscopy, with maximal voluntary contractions (MVC of the relevant muscles being performed post-exercise to provide a frame of reference for normalising the exercise-related oxygenation responses across subjects. Above supra-ӨL, VO2 rose in an exponential-like fashion ("phase 2, with a delayed VO2sc subsequently developing. This was accompanied by an increase in [reduced haemoglobin] relative to baseline (∆[Hb], which attained 79 ± 13 % (mean, SD of MVC maximum in vastus lateralis at end-exercise and 52 ± 27 % in biceps brachii. Biceps brachii ∆[Hb] was significantly correlated with VO2 throughout the slow phase. In contrast, for sub- L exercise, VO2 rose exponentially to reach a steady state with a more modest increase in vastus lateralis ∆[Hb] (30 ± 11 %; biceps brachii ∆[Hb] was minimally affected (8 ± 2 %. That the intramuscular O2 desaturation profile in biceps brachii was proportional to that for VO2sc during supra-ӨL cycle ergometry is consistent with additional stabilizing arm work contributing to the VO2sc

  15. Oxygen regulation of nitrate uptake in denitrifying Pseudomonas aeruginosa.

    OpenAIRE

    Hernandez, D; Rowe, J J

    1987-01-01

    Oxygen had an immediate and reversible inhibitory effect on nitrate respiration by denitrifying cultures of Pseudomonas aeruginosa. Inhibition of nitrate utilization by oxygen appeared to be at the level of nitrate uptake, since nitrate reduction to nitrite in cell extracts was not affected by oxygen. The degree of oxygen inhibition was dependent on the concentration of oxygen, and increasing nitrate concentrations could not overcome the inhibition. The inhibitory effect of oxygen was maximal...

  16. Aerobic fitness related to cardiovascular risk factors in young children

    DEFF Research Database (Denmark)

    Dencker, Magnus; Thorsson, Ola; Karlsson, Magnus K

    2012-01-01

    Low aerobic fitness (maximum oxygen uptake (VO(2PEAK))) is predictive for poor health in adults. In a cross-sectional study, we assessed if VO(2PEAK) is related to a composite risk factor score for cardiovascular disease (CVD) in 243 children (136 boys and 107 girls) aged 8 to 11 years. VO(2PEAK...

  17. Muscular Oxygen Uptake Kinetics in Aged Adults.

    Science.gov (United States)

    Koschate, J; Drescher, U; Baum, K; Eichberg, S; Schiffer, T; Latsch, J; Brixius, K; Hoffmann, U

    2016-06-01

    Pulmonary oxygen uptake (V˙O2) kinetics and heart rate kinetics are influenced by age and fitness. Muscular V˙O2 kinetics can be estimated from heart rate and pulmonary V˙O2. In this study the applicability of a test using pseudo-random binary sequences in combination with a model to estimate muscular V˙O2 kinetics was tested. Muscular V˙O2 kinetics were expected to be faster than pulmonary V˙O2 kinetics, slowed in aged subjects and correlated with maximum V˙O2 and heart rate kinetics. 27 elderly subjects (73±3 years; 81.1±8.2 kg; 175±4.7 cm) participated. Cardiorespiratory kinetics were assessed using the maximum of cross-correlation functions, higher maxima implying faster kinetics. Muscular V˙O2 kinetics were faster than pulmonary V˙O2 kinetics (0.31±0.1 vs. 0.29±0.1 s; p=0.004). Heart rate kinetics were not correlated with muscular or pulmonary V˙O2 kinetics or maximum V˙O2. Muscular V˙O2 kinetics correlated with maximum V˙O2 (r=0.35; p=0.033). This suggests, that muscular V˙O2 kinetics are faster than estimates from pulmonary V˙O2 and related to maximum V˙O2 in aged subjects. In the future this experimental approach may help to characterize alterations in muscular V˙O2 under various conditions independent of motivation and maximal effort. © Georg Thieme Verlag KG Stuttgart · New York.

  18. Muscle glycogen reduction in man: relationship between surface EMG activity and oxygen uptake kinetics during heavy exercise.

    Science.gov (United States)

    Osborne, Mark A; Schneider, Donald A

    2006-01-01

    The purpose of this study was to determine whether muscle glycogen reduction prior to exercise would alter muscle fibre recruitment pattern and change either on-transient O2 uptake (VO2) kinetics or the VO2 slow component. Eight recreational cyclists (VO2peak, 55.6 +/- 1.3 ml kg (-1) min(-1)) were studied during 8 min of heavy constant-load cycling performed under control conditions (CON) and under conditions of reduced type I muscle glycogen content (GR). VO2 was measured breath-by-breath for the determination of VO2 kinetics using a double-exponential model with independent time delays. VO2 was higher in the GR trial compared to the CON trial as a result of augmented phase I and II amplitudes, with no difference between trials in the phase II time constant or the magnitude of the slow component. The mean power frequency (MPF) of electromyography activity for the vastus medialis increased over time during both trials, with a greater rate of increase observed in the GR trial compared to the CON trial. The results suggest that the recruitment of additional type II motor units contributed to the slow component in both trials. An increase in fat metabolism and augmented type II motor unit recruitment contributed to the higher VO2 in the GR trial. However, the greater rate of increase in the recruitment of type II motor units in the GR trial may not have been of sufficient magnitude to further elevate the slow component when VO2 was already high and approaching VO2peak .

  19. 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...

  20. Oxygen uptake rate (OUR) control strategy for improving avermectin B

    African Journals Online (AJOL)

    Glucose metabolism plays a crucial role in the process of avermectin B1a biosynthesis. Controlling glucose feeding based on oxygen uptake rate (OUR) was established to improve the efficiency of avermectin B1a production. The result showed that avermectin B1a production was greatly enhanced by OUR control strategy.

  1. OXYGEN UPTAKE KINETICS IN SPORT, EXERCISE AND MEDICINE

    Directory of Open Access Journals (Sweden)

    David C. Poole

    2005-03-01

    Full Text Available The objective of the book is to discuss the principal determinants of oxygen uptake dynamics which is essential to developing exercise performance and improving quality of life for patients, especially those with cardio-respiratory diseases. A broad review of the current knowledge about this relatively less studied field is provided by this book. Incidentally, it updates the reader about how a person can use his/her aerobic energy system more effectively in order to fatigue gradually and be able to endure more physical activity. It also discusses the effects of exercise training in speeding up oxygen uptake kinetics, and the effects of ageing and a selection of conditions in slowing oxygen dynamics and declining exercise capacity.

  2. Embrittlement of zircaloy cladding due to oxygen uptake (CBRTTL)

    International Nuclear Information System (INIS)

    Reymann, G.A.

    1979-02-01

    A model for embrittlement of zircaloy due to oxygen uptake at high temperatures is described. The model defines limits for oxygen content and temperature which, if exceeded, give rise to zircaloy cladding which is sufficiently embrittled to cause failure either on quenching or normal handling following a transient. A significant feature of this model is that the onset of embrittlement is dependent on the cooling rate. A distinction is made between slow and fast cooling, with the boundary at 100 K/s. The material property correlations and computer subcodes described in MATPRO are developed for use in Light Water Reactor (LWR) codes

  3. Measuring oxygen uptake in fishes with bimodal respiration.

    Science.gov (United States)

    Lefevre, S; Bayley, M; McKenzie, D J

    2016-01-01

    Respirometry is a robust method for measurement of oxygen uptake as a proxy for metabolic rate in fishes, and how species with bimodal respiration might meet their demands from water v. air has interested researchers for over a century. The challenges of measuring oxygen uptake from both water and air, preferably simultaneously, have been addressed in a variety of ways, which are briefly reviewed. These methods are not well-suited for the long-term measurements necessary to be certain of obtaining undisturbed patterns of respiratory partitioning, for example, to estimate traits such as standard metabolic rate. Such measurements require automated intermittent-closed respirometry that, for bimodal fishes, has only recently been developed. This paper describes two approaches in enough detail to be replicated by the interested researcher. These methods are for static respirometry. Measuring oxygen uptake by bimodal fishes during exercise poses specific challenges, which are described to aid the reader in designing experiments. The respiratory physiology and behaviour of air-breathing fishes is very complex and can easily be influenced by experimental conditions, and some general considerations are listed to facilitate the design of experiments. Air breathing is believed to have evolved in response to aquatic hypoxia and, probably, associated hypercapnia. The review ends by considering what realistic hypercapnia is, how hypercapnic tropical waters can become and how this might influence bimodal animals' gas exchange. © 2015 The Fisheries Society of the British Isles.

  4. Determinants of maximal oxygen uptake in severe acute hypoxia

    DEFF Research Database (Denmark)

    Calbet, J A L; Boushel, Robert Christopher; Rådegran, G

    2003-01-01

    To unravel the mechanisms by which maximal oxygen uptake (VO2 max) is reduced with severe acute hypoxia in humans, nine Danish lowlanders performed incremental cycle ergometer exercise to exhaustion, while breathing room air (normoxia) or 10.5% O2 in N2 (hypoxia, approximately 5,300 m above sea......: 1) reduction of PiO2, 2) impairment of pulmonary gas exchange, and 3) reduction of maximal cardiac output and peak leg blood flow, each explaining about one-third of the loss in VO2 max....

  5. Aerobic capacity related to cardiac size in young children

    DEFF Research Database (Denmark)

    Dencker, M; Wollmer, P; Karlsson, M

    2013-01-01

    Aerobic capacity, defined as peak oxygen uptake (VO2PEAK), is generally considered to be the best single marker for aerobic fitness. We assessed if VO2PEAK is related to different cardiac dimensions in healthy young children on a population base.......Aerobic capacity, defined as peak oxygen uptake (VO2PEAK), is generally considered to be the best single marker for aerobic fitness. We assessed if VO2PEAK is related to different cardiac dimensions in healthy young children on a population base....

  6. Aerobic exercise capacity at long-term follow-up after paediatric allogeneic haematopoietic SCT

    DEFF Research Database (Denmark)

    Mathiesen, S; Uhlving, H H; Buchvald, F

    2014-01-01

    Peak oxygen uptake (VO2peak), a measure of aerobic exercise capacity, predicts mortality and morbidity in healthy and diseased individuals. Our aim was to determine VO2peak years after paediatric allogeneic haematopoietic SCT (HSCT) and to identify associations with baseline patient and donor...... type or GvHD were found. Although causes for reduced VO2peak may be multiple, our findings stress the need to focus on physical activity post HSCT to prevent lifestyle diseases and improve quality of life....

  7. Oxygen uptake during the γ-irradiation of fatty acids

    International Nuclear Information System (INIS)

    Metwally, M.M.K.; Moore, J.S.

    1987-01-01

    The radiation-induced oxidation of saturated and unsaturated fatty acids in aqueous solutions has been estimated by measurement of the continuous uptake of oxygen using an oxygen electrode. Chain reactions, initiated by HO radicals, are easily identified to be occurring in the case of unsaturated fatty acids. Other mild oxidation agents, namely (SCN)2 -anion radicals, Br 2 - anion radicals and N 3 -anion radicals, are also found to be capable of oxidizing the polyunsaturated fatty acids. Evidence is presented the O 2- anion radicals may also initiate peroxidation. The oxidation of the polyunsaturated fatty acids is dependent on dose rate, fatty acid concentration, temperature and the presence of antioxidant and other protective agents. Kinetic studies of the reaction of (SCN)2 - anion radicals and Br 2 - anion radicals with linoleic and linolenic acids have been carried out using pulse radiolysis. The bimolecular rate constants for both radical species with the lipids are approx 10 7 mol-? 1 dm 3 s -1 , below their critical micelle concentrations, and decrease at higher concentrations due to micelle formation. (author)

  8. Critical evaluation of oxygen-uptake assessment in swimming.

    Science.gov (United States)

    Sousa, Ana; Figueiredo, Pedro; Pendergast, David; Kjendlie, Per-Ludvik; Vilas-Boas, João P; Fernandes, Ricardo J

    2014-03-01

    Swimming has become an important area of sport science research since the 1970s, with the bioenergetic factors assuming a fundamental performance-influencing role. The purpose of this study was to conduct a critical evaluation of the literature concerning oxygen-uptake (VO2) assessment in swimming, by describing the equipment and methods used and emphasizing the recent works conducted in ecological conditions. Particularly in swimming, due to the inherent technical constraints imposed by swimming in a water environment, assessment of VO2max was not accomplished until the 1960s. Later, the development of automated portable measurement devices allowed VO2max to be assessed more easily, even in ecological swimming conditions, but few studies have been conducted in swimming-pool conditions with portable breath-by-breath telemetric systems. An inverse relationship exists between the velocity corresponding to VO2max and the time a swimmer can sustain it at this velocity. The energy cost of swimming varies according to its association with velocity variability. As, in the end, the supply of oxygen (whose limitation may be due to central-O2 delivery and transportation to the working muscles-or peripheral factors-O2 diffusion and utilization in the muscles) is one of the critical factors that determine swimming performance, VO2 kinetics and its maximal values are critical in understanding swimmers' behavior in competition and to develop efficient training programs.

  9. Partitioning of oxygen uptake between the gills and skin in fish larvae: a novel method for estimating cutaneous oxygen uptake.

    Science.gov (United States)

    Rombough, P J

    1998-06-01

    The goal of this study was to develop an alternative to the traditional rubber dam method for measuring cutaneous oxygen uptake in bimodally respiring (skin + gills) fish larvae. The method tested involved using microelectrodes to measure the PO2 gradient in the diffusive boundary layer adjacent to seven positions on the skin surface (one on the head, two on the yolk sac, two on the trunk, one at the base of the dorsal fin-fold and one on the proximal portion of the caudal fin-fold) of rainbow trout (Oncorhynchus mykiss) larvae in still water. The PO2 gradient (deltaPO2/delta x, where x is the distance from the skin surface) was then used to calculate area-specific rate of O2 uptake (.MO2/A) according to the Fick equation, .MO2/A=Dbeta(deltaPO2/deltax), where A is the cross-sectional area of the boundary layer, D is the diffusion coefficient and beta is the capacitance coefficient for O2 in water. The accuracy of the method was assessed by comparing it with the rubber dam method. After correcting for differences in body mass, the two methods gave essentially identical results. According to the boundary layer method, the mean (+/-95 % CI) rate of O2 uptake across the skin of newly hatched rainbow trout at 10 degrees C is 3.13+/-0.18 microg O2 cm-2h-1 (N=265). The corresponding value obtained using the rubber dam method was 3. 36+/-0.35 microg O2 cm-2 h-1 (N=27). The advantages of the boundary layer method are that it can be used with smaller, more delicate larvae and that variables, such as flow rate, that can affect the efficiency of gas exchange can be regulated more precisely. The boundary layer method also permits examination of regional differences in exchange efficiency, although in still water such differences do not appear to be significant in trout larvae. The mean steepness of the PO2 gradient in the boundary layer and, hence, the mean rate of area-specific O2 uptake were essentially the same (P>0.05) at all seven locations tested in this study. The

  10. Comparison of specific oxygen uptake rates of two beach-scale ...

    African Journals Online (AJOL)

    The determined values of oxygen uptake rate during the endogenous reaction phase (between 0.1054 and 0.3564 mgO2/L.minute) and concentrations of mixed liquor suspended solids (between 1183 and 1957 mgMLSS/L) are comparable to those reported elsewhere in literature. Results of specific oxygen uptake rate of ...

  11. Response profiles of oxygen uptake efficiency during exercise in healthy children

    NARCIS (Netherlands)

    Bongers, Bart C.; Hulzebos, Erik H J; Helbing, Willem A.; Ten Harkel, Arend D J; Van Brussel, Marco; Takken, Tim

    2015-01-01

    Background Oxygen uptake efficiency (OUE), the relation between oxygen uptake (VO2) and minute ventilation (VE), differs between healthy children and children with heart disease. This study aimed to investigate the normal response profiles of OUE during a progressive cardiopulmonary exercise test.

  12. Heart Rate and Oxygen Uptake Recovery and the Level of Aerobic Capacity in Mountain Bikers

    Directory of Open Access Journals (Sweden)

    Michalik Kamil

    2017-12-01

    Full Text Available Introduction. Since mountain biking involves exercise of varying intensity, competitive performance may be affected by the rate of recovery. The aim of the current study was to determine whether maximal oxygen uptake is associated with the rate of heart rate and oxygen uptake recovery in mountain bike athletes.

  13. Pediatric Exercise Testing: Value and Implications of Peak Oxygen Uptake

    Directory of Open Access Journals (Sweden)

    Paolo T. Pianosi

    2017-01-01

    Full Text Available Peak oxygen uptake (peak V ˙ O 2 measured by clinical exercise testing is the benchmark for aerobic fitness. Aerobic fitness, estimated from maximal treadmill exercise, is a predictor of mortality in adults. Peak V ˙ O 2 was shown to predict longevity in patients aged 7–35 years with cystic fibrosis over 25 years ago. A surge of exercise studies in young adults with congenital heart disease over the past decade has revealed significant prognostic information. Three years ago, the first clinical trial in children with pulmonary arterial hypertension used peak V ˙ O 2 as an endpoint that likewise delivered clinically relevant data. Cardiopulmonary exercise testing provides clinicians with biomarkers and clinical outcomes, and researchers with novel insights into fundamental biological mechanisms reflecting an integrated physiological response hidden at rest. Momentum from these pioneering observations in multiple disease states should impel clinicians to employ similar methods in other patient populations; e.g., sickle cell disease. Advances in pediatric exercise science will elucidate new pathways that may identify novel biomarkers. Our initial aim of this essay is to highlight the clinical relevance of exercise testing to determine peak V ˙ O 2 , and thereby convince clinicians of its merit, stimulating future clinical investigators to broaden the application of exercise testing in pediatrics.

  14. Peak oxygen uptake in a sprint interval testing protocol vs. maximal oxygen uptake in an incremental testing protocol and their relationship with cross-country mountain biking performance.

    Science.gov (United States)

    Hebisz, Rafał; Hebisz, Paulina; Zatoń, Marek; Michalik, Kamil

    2017-04-01

    In the literature, the exercise capacity of cyclists is typically assessed using incremental and endurance exercise tests. The aim of the present study was to confirm whether peak oxygen uptake (V̇O 2peak ) attained in a sprint interval testing protocol correlates with cycling performance, and whether it corresponds to maximal oxygen uptake (V̇O 2max ) determined by an incremental testing protocol. A sample of 28 trained mountain bike cyclists executed 3 performance tests: (i) incremental testing protocol (ITP) in which the participant cycled to volitional exhaustion, (ii) sprint interval testing protocol (SITP) composed of four 30 s maximal intensity cycling bouts interspersed with 90 s recovery periods, (iii) competition in a simulated mountain biking race. Oxygen uptake, pulmonary ventilation, work, and power output were measured during the ITP and SITP with postexercise blood lactate and hydrogen ion concentrations collected. Race times were recorded. No significant inter-individual differences were observed in regards to any of the ITP-associated variables. However, 9 individuals presented significantly increased oxygen uptake, pulmonary ventilation, and work output in the SITP compared with the remaining cyclists. In addition, in this group of 9 cyclists, oxygen uptake in SITP was significantly higher than in ITP. After the simulated race, this group of 9 cyclists achieved significantly better competition times (99.5 ± 5.2 min) than the other cyclists (110.5 ± 6.7 min). We conclude that mountain bike cyclists who demonstrate higher peak oxygen uptake in a sprint interval testing protocol than maximal oxygen uptake attained in an incremental testing protocol demonstrate superior competitive performance.

  15. Activation-induced resetting of cerebral oxygen and glucose uptake in the rat

    DEFF Research Database (Denmark)

    Madsen, P L; Linde, R; Hasselbalch, S G

    1998-01-01

    In the clinical setting it has been shown that activation will increase cerebral glucose uptake in excess of cerebral oxygen uptake. To study this phenomenon further, this study presents an experimental setup that enables precise determination of the ratio between cerebral uptake of glucose...... and oxygen in the awake rat. Global CBF was measured by the Kety-Schmidt technique, and the ratio between cerebral uptake rates for oxygen, glucose, and lactate was calculated from cerebral arterial-venous differences. During baseline conditions, rats were kept in a closed box designed to minimize...... interference. During baseline conditions CBF was 1.08 +/- 0.25 mL x g(-1) x minute(-1), and the cerebral oxygen to glucose uptake ratio was 5.5. Activation was induced by opening the sheltering box for 6 minutes. Activation increased CBF to 1.81 mL x g(-1) x minute(-1). During activation cerebral glucose...

  16. Pediatric exercise testing. In health and disease

    NARCIS (Netherlands)

    Bongers, B.C.

    2013-01-01

    Measuring peak oxygen uptake (VO2peak) during progressive cardiopulmonary exercise testing (CPET) up to maximal exertion is widely recognized as the best single measure of aerobic exercise capacity. It is an important determinant of health, even in childhood and adolescence. Measuring VO2peak

  17. Thromboxane plays a role in postprandial jejunal oxygen uptake and capillary exchange.

    Science.gov (United States)

    Alemayehu, A; Chou, C C

    1990-09-01

    The effects of a thromboxane A2 (TxA2)-endoperoxide receptor antagonist, SQ 29548, on jejunal blood flow, oxygen uptake, and capillary filtration coefficient (Kfc) were determined in anesthetized dogs under resting conditions and during the presence of predigested food in the jejunal lumen in three series of experiments. In series 1, 2.0 micrograms intra-arterial administration of SQ 29548 was found to abolish completely the vasoconstrictor action of graded doses (0.05-2.0 micrograms) of intra-arterial injection of a TxA2-endoperoxide analogue, U44069. SQ 29548 (2.0 micrograms ia) per se did not significantly alter resting jejunal blood flow, oxygen uptake, capillary pressure, or Kfc. Before SQ 29548, placement of food plus bile into the jejunal lumen increased blood flow +42 +/- 9%, oxygen uptake +28 +/- 7%, and Kfc +24 +/- 6%. After SQ 29548, the food placement increased blood flow +37 +/- 8%, oxygen uptake +52 +/- 11%, and Kfc +63 +/- 20%. The food-induced increases in oxygen uptake and Kfc after SQ 29548 were significantly greater than those induced before the blocking of TxA2-endoperoxide receptors by SQ 29548. Our study indicates that endogenous thromboxane does not play a role in regulating jejunal blood flow, capillary filtration, and oxygen uptake under resting conditions. However, it plays a role in limiting the food-induced increases in jejunal oxygen uptake and capillary exchange capacity without influencing the food-induced hyperemia.

  18. Estimation of maximal oxygen uptake without exercise testing in Korean healthy adult workers.

    Science.gov (United States)

    Jang, Tae-Won; Park, Shin-Goo; Kim, Hyoung-Ryoul; Kim, Jung-Man; Hong, Young-Seoub; Kim, Byoung-Gwon

    2012-08-01

    Maximal oxygen uptake is generally accepted as the most valid and reliable index of cardiorespiratory fitness and functional aerobic capacity. The exercise test for measuring maximal oxygen uptake is unsuitable for screening tests in public heath examinations, because of the potential risks of exercise exertion and time demands. We designed this study to determine whether work-related physical activity is a potential predictor of maximal oxygen uptake, and to develop a maximal oxygen uptake equation using a non-exercise regression model for the cardiorespiratory fitness test in Korean adult workers. Study subjects were adult workers of small-sized companies in Korea. Subjects with history of disease such as hypertension, diabetes, asthma and angina were excluded. In total, 217 adult subjects (113 men of 21-55 years old and 104 women of 20-64 years old) were included. Self-report questionnaire survey was conducted on study subjects, and maximal oxygen uptake of each subject was measured with the exercise test. The statistical analysis was carried out to develop an equation for estimating maximal oxygen uptake. The predictors for estimating maximal oxygen uptake included age, gender, body mass index, smoking, leisure-time physical activity and the factors representing work-related physical activity. The work-related physical activity was identified to be a predictor of maximal oxygen uptake. Moreover, the equation showed high validity according to the statistical analysis. The equation for estimating maximal oxygen uptake developed in the present study could be used as a screening test for assessing cardiorespiratory fitness in Korean adult workers.

  19. 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.

  20. [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.

  1. Low blood flow at onset of moderate-intensity exercise does not limit muscle oxygen uptake

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Mortensen, Stefan P; Saltin, Bengt

    2010-01-01

    The effect of low blood flow at onset of moderate-intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5-min one-legged knee-extensor exercise bout (24 +/- 1 W, mean +/- SD) without (Con) and with (double blockade; DB) arterial infusion...... of inhibitors of nitric oxide synthase (N(G)-monomethyl-l-arginine) and cyclooxygenase (indomethacin) to inhibit the synthesis of nitric oxide and prostanoids, respectively. Leg blood flow and leg oxygen delivery throughout exercise was 25-50% lower (P ... +/- 12 vs. 262 +/- 39 ml/min). The present data demonstrate that muscle blood flow and oxygen delivery can be markedly reduced without affecting muscle oxygen uptake in the initial phase of moderate-intensity exercise, suggesting that blood flow does not limit muscle oxygen uptake at the onset...

  2. Increased Brain Glucose Uptake After 12 Weeks of Aerobic High-Intensity Interval Training in Young and Older Adults.

    Science.gov (United States)

    Robinson, Matthew M; Lowe, Val J; Nair, K Sreekumaran

    2018-01-01

    Aerobic exercise training can increase brain volume and blood flow, but the impact on brain metabolism is less known. We determined whether high-intensity interval training (HIIT) increases brain metabolism by measuring brain glucose uptake in younger and older adults. Brain glucose uptake was measured before and after HIIT or a sedentary (SED) control period within a larger exercise study. Study procedures were performed at the Mayo Clinic in Rochester, MN. Participants were younger (18 to 30 years) or older (65 to 80 years) SED adults who were free of major medical conditions. Group sizes were 15 for HIIT (nine younger and six older) and 12 for SED (six younger and six older). Participants completed 12 weeks of HIIT or SED. HIIT was 3 days per week of 4 × 4 minute intervals at over 90% of peak aerobic capacity (VO2peak) with 2 days per week of treadmill walking at 70% VO2peak. Resting brain glucose uptake was measured using 18F-fluorodeoxyglucose positron emission tomography scans at baseline and at week 12. Scans were performed at 96 hours after exercise. VO2peak was measured by indirect calorimetry. Glucose uptake increased significantly in the parietal-temporal and caudate regions after HIIT compared with SED. The gains with HIIT were not observed in all brain regions. VO2peak was increased for all participants after HIIT and did not change with SED. We demonstrate that brain glucose metabolism increased after 12 weeks of HIIT in adults in regions where it is reduced in Alzheimer's disease. Copyright © 2017 Endocrine Society

  3. Ghost crabs on a treadmill: Oxygen Uptake and Haemocyanin ...

    African Journals Online (AJOL)

    Ghost crabs Ocypode ceratophthalmus were exercised on a specially constructed treadmill. At a running speed of 13,3 cm s-1, most crabs ran for 2 h before getting fatigued. At this speed the oxygen consumption rate (MO2) was measured in time intervals for a total of 52 min. For exercised crabs the MO2 values are about ...

  4. (-)-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.

  5. Exertional oxygen uptake kinetics: a stamen of stamina?

    Science.gov (United States)

    Whipp, Brian J; Rossiter, H B; Ward, S A

    2002-04-01

    The fundamental pulmonary O(2) uptake (.VO(2)) response to moderate, constant-load exercise can be characterized as (d.VO(2)/dt)(tau)+Delta.VO(2) (t)=Delta.VO(2SS) where Delta.VO(2SS) is the steady-state response, and tau is the time constant, with the .VO(2) kinetics reflecting intramuscular O(2) uptake (.QO(2)) kinetics, to within 10%. The role of phosphocreatine (PCr) turnover in .QO(2) control can be explored using (31)P-MR spectroscopy, simultaneously with .VO(2). Although tau.VO(2) and tauPCr vary widely among subjects (approx. 20-65 s), they are not significantly different from each other, either at the on- or off-transient. A caveat to interpreting the "well-fit" exponential is that numerous units of similar Delta.VO(2SS) but with a wide tau distribution can also yield a .VO(2) response with an apparent single tau. This tau is, significantly, inversely correlated with lactate threshold and .VO(2max)(but is poorly predictive; a frail stamen, therefore), consistent with tau not characterizing a compartment with uniform kinetics. At higher intensities, the fundamental kinetics become supplemented with a slowly-developing phase, setting .VO(2)on a trajectory towards maximum .VO(2). This slow component is also demonstrable in Delta[PCr]: the decreased efficiency thereby reflecting a predominantly high phosphate-cost of force production rather than a high O(2)-cost of phosphate production. We also propose that the O(2)-deficit for the slow-component is more likely to reflect shifting Delta.VO(2SS) rather than a single one with a single tau.

  6. Inhibition of total oxygen uptake by silica nanoparticles in activated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Sibag, Mark [Department of Environment and Energy, Sejong University, 98 Gunja-Dong, Gwangjin-Gu, Seoul 143-747 (Korea, Republic of); Choi, Byeong-Gyu [School of Civil, Environmental and Architectural Engineering, Korea University, 145, Anam-ro, Sungbuk-ku, Seoul 136-701 (Korea, Republic of); Suh, Changwon [Energy Lab, Environment Group, Samsung Advanced Institute of Technology, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803 (Korea, Republic of); Lee, Kwan Hyung; Lee, Jae Woo [Department of Environmental Engineering and Program in Environmental Technology and Policy, Korea University, Sejong 339-700 (Korea, Republic of); Maeng, Sung Kyu [Department of Civil and Environmental Engineering, Sejong University, 98 Gunja-Dong, Gwangjin-Gu, Seoul 143-747 (Korea, Republic of); Cho, Jinwoo, E-mail: jinwoocho@sejong.edu [Department of Environment and Energy, Sejong University, 98 Gunja-Dong, Gwangjin-Gu, Seoul 143-747 (Korea, Republic of)

    2015-02-11

    Highlights: • Silica nanoparticles (SNP) inhibit total oxygen uptake in activated sludge. • Relatively smaller SNP are inhibitorier than larger SNP. • SNP alters C15:0, C16:0 and C18:0 in activated sludge fatty acid methyl ester profile. - Abstract: Nanoparticle toxicity to biological activities in activated sludge is largely unknown. Among the widely used nanoparticles, silica nanoparticles (SNP) have a limited number of studies associated with inhibition to the activated sludge process (ASP). We demonstrated SNP inhibition of activated sludge respiration through oxygen uptake rate (OUR) measurement. Based on the percentage inhibition of total oxygen consumption (I{sub T}), we observed that smaller SNPs (12 nm, I{sub T} = 33 ± 3%; 151 nm, I{sub T} = 23 ± 2%) were stronger inhibitors than larger SNPs (442 and 683 nm, I{sub T} = 5 ± 1%). Transmission electron micrographs showed that some of the SNPs were adsorbed on and/or apparently embedded somewhere in the microbial cell membrane. Whether SNPs are directly associated with the inhibition of total oxygen uptake warrants further studies. However, it is clear that SNPs statistically significantly altered the composition of microbial membrane lipids, which was more clearly described by principal component analysis and weighted Euclidian distance (PCA-ED) of the fatty acid methyl ester (FAME) data. This study suggests that SNPs potentially affect the biological activity in activated sludge through the inhibition of total oxygen uptake.

  7. Eddy correlation measurements of oxygen uptake in deep ocean sediments

    DEFF Research Database (Denmark)

    Berg, P.; Glud, Ronnie Nøhr; Hume, A.

    2010-01-01

    .62 +/- 0.23 (SE, n = 7), 1.65 +/- 0.33 (n = 2), and 1.43 +/- 0.15 (n = 25) mmol m(-2) d(-1). The very good agreement between the eddy correlation flux and the chamber flux serves as a new, important validation of the eddy correlation technique. It demonstrates that the eddy correlation instrumentation......Abstract: We present and compare small sediment-water fluxes of O-2 determined with the eddy correlation technique, with in situ chambers, and from vertical sediment microprofiles at a 1450 m deep-ocean site in Sagami Bay, Japan. The average O-2 uptake for the three approaches, respectively, was 1...... available today is precise and can resolve accurately even very small benthic O-2 fluxes. The correlated fluctuations in vertical velocity and O-2 concentration that give the eddy flux had average values of 0.074 cm s(-1) and 0.049 mu M. The latter represents only 0.08% of the 59 mu M mean O-2 concentration...

  8. Oxygen-18 as a tool for studying photorespiration. Oxygen uptake and incorporation into glycolate, glycine and serine

    International Nuclear Information System (INIS)

    Gerster, R.; Dimon, B.; Tournier, P.; Peybernes, A.

    1977-01-01

    The intensity of photosynthesis and photorespiration has been determined by measuring 16 O 2 evolvement and 18 O 2 uptake on algae and leaves. In the case of algae, there is still an important oxygen uptake even when ribulose diphosphate oxygenase is inhibited by 10 -3 M cyanide. Oxygen-18 incorporation into glycolate, glycine and serine of photorespiring algae and leaves exposed to atmospheres containing 18 O 2 has also been measured. Only one of the two atoms present in molecular oxygen was incorporated into the carboxyl group of the glycolate excreted from algae; the rate of 18 O incorporation was important (65 to 80% according to experimental conditions), even in the presence of 10 -3 M cyanide. Thus, oxidation of ribulose diphosphate is not the sole reaction leading to 18 O glycolate synthesis. In the case of maize, there was a rapid and important 18 O incorporation into the carboxyl group of glycine and serine, the kinetics of which was determined as a function of CO 2 presence in the atmosphere. These results suggest that photorespiration is also operating in C 4 species. Furthermore, in vitro experiments showed that phosphorylated ceto-acids of the Calvin cycle were very sensitive to H 2 O 2 ; the corresponding reaction can explain O 2 uptake and 18 O labelling of glycolate. (author)

  9. Vasopressin and angiotensin II stimulate oxygen uptake in the perfused rat hindlimb

    DEFF Research Database (Denmark)

    Colquhoun, E Q; Hettiarachchi, M; Ye, J M

    1988-01-01

    Vasopressin and angiotensin II markedly stimulated oxygen uptake in the perfused rat hindlimb. The increase due to each agent approached 70% of the basal rate, and was greater than that produced by a maximal concentration of norepinephrine. Half-maximal stimulation occurred at 60 pM vasopressin, 0...

  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. Longitudinal Changes in Physical Activity Level, Body Mass Index, and Oxygen Uptake Among Norwegian Adolescents

    Directory of Open Access Journals (Sweden)

    Pål Lagestad

    2018-03-01

    Full Text Available Several studies have investigated activity levels among adolescents, but no study has examined longitudinal changes in physical activity (PA level, body mass, and oxygen uptake among the same adolescents from the age of 14 to 19 years. The present study examined data from a research project that included a group of randomly selected students (N = 116 with objective measurements of PA (accelerometer data, self-reported PA level, and body mass and oxygen uptake during a 5-year period. The results show a significant decrease in the accelerometer-based PA level over time, from age 14 to 19. At 14 years of age, the minutes of moderate and/or vigorous PA was 66.7 min·day−1, but was less than half, at only 24.4 min·day−1, at 19 years of age. The self-reported activity data show a decrease in girls’ general activity level over time, while boys’ activity level during school breaks decreased strongly during the period: at age 14, 61% of the boys were classified as active, while at age 19, only 11% were physically active. Furthermore, body mass index increased during the period for both genders, while oxygen uptake decreased. Since both BMI and maximal oxygen uptake are important risk factors for future CVD, these findings point toward the importance of maintaining a high activity level during childhood and adolescence, in order to keep fit later in life.

  12. Central Cardiovascular Responses of Quadriplegic Subjects to Arm Exercise at Varying Levels of Oxygen Uptake.

    Science.gov (United States)

    Figoni, Stephen F.

    The purpose of this study was to assess selected central cardiovascular functions of spinal cord injured, quadriplegic subjects at varying levels of oxygen uptake (VO sub 2). Subjects included 11 untrained, male college students with C5, C6, or C7 complete quadriplegia and 11 able-bodied reference subjects. Exercise was performed on a Monark cycle…

  13. Allometric scaling of peak oxygen uptake in male roller hockey players under 17 years old

    NARCIS (Netherlands)

    Valente-dos-Santos, J.; Sherar, L.; Coelho-e-Silva, MJ; Pereira, J.R.; Vaz, V.; Cupido-dos-Santos, A.; Baxter-Jones, A.; Visscher, C.; Elferink-Gemser, M.T.; Malina, R.M.

    Peak oxygen uptake ((V) over dotO(2peak)) is routinely expressed in litres per minute and by unit of body mass (mL.kg(-1).min(-1)) despite the theoretical and statistical limitations of using ratios. Allometric modeling is an effective approach for partitioning body-size effects in a performance

  14. Alterations in Strength and Maximal Oxygen Uptake Consequent to Nautilus Circuit Weight Training.

    Science.gov (United States)

    Messier, Stephen P.; Dill, Mary Elizabeth

    1985-01-01

    The study compared the effects on muscular strength and maximal oxygen uptake of a Nautilus circuit weight training program, a free weight strength training program, and a running program. Nautilus circuit weight training appears to be equally effective for a training period of short duration. (MT)

  15. Dynamics and Thermochemistry of Oxygen Uptake by a Mixed Ce-Pr Oxide

    Science.gov (United States)

    Sinev, M. Yu.; Fattakhova, Z. T.; Bychkov, V. Yu.; Lomonosov, V. I.; Gordienko, Yu. A.

    2018-03-01

    The dynamics of oxygen uptake by mixed Ce0.55Pr0.45O2-x oxide is studied in a pulsed oxygen supply mode using in situ high-temperature heat flow differential scanning calorimetry. It is stated that the oxidation proceeds in two regimes: a fast one at the beginning of the oxidation process, and a slow one, which is controlled by the diffusion of oxygen through the bulk of the solid at the later stages of the process. Analysis of the shape of calorimetric profiles reveals some processes, accompanied by heat release, that occur in the sample in the absence of oxygen in the gas phase. These could be due to both the redistribution of consumed oxygen in the oxide lattice and the lattice relaxation associated with the transformation of phases with different arrangements of oxygen vacancies in them. The heat effect (which diminishes from 60 to 40 kJ/mol in the course of oxygen uptake) associated with the oxidation of the reduced form of mixed Ce-Pr oxide, corresponds to the oxidation of praseodymium ions from (3+) to (4+).

  16. Oxygen uptake during the exercise: temporal aspectos and adjustments of curves

    Directory of Open Access Journals (Sweden)

    Fernando Roberto de Oliveira

    2004-12-01

    Full Text Available The oxygen uptake has been considered as one of the most important physiological variables for exercise physiology. The first models relating oxygen uptake with performance emerged in the beginning of last century and it has been intensely discussed in the literature until today. This review discussed some topics about oxygen uptake, more specifically on aspects related with the kinetic and influences of the time response of this variable on the adjustment curve during an incremental test. Discussion on the level of aerobic condition and exercise intensity on the kinetics of oxygen uptake are also included in the text. Finally, verification on the slow component and on the physiological control of the oxygen uptake kinetics is also presented. RESUMO O consumo de oxigênio tem sido considerado uma das variáveis fisiológicas mais importantes para a fisiologia do exercício. Os primeiros modelos relacionando o consumo de oxigênio com o desempenho esportivo surgiram no inicio do século passado e continua sendo intensamente discutido na literatura atual. A presenterevisão discutiu alguns tópicos sobre consumo de oxigênio, mais especificamente sobre aspectos relacionados à cinética e a influencia do tempo de resposta dessa variável sobre os ajustes de curva em teste progressivo. Discussões relacionadas a influencia do nível de aptidão aeróbia e a intensidade do exercício sobre a cinética do consumo de oxigênio também estão inseridas no texto. Por fim, algumas constatações sobre componente lento e os controles fisiológicos da cinética do consumo de oxigênio são abordados.

  17. Oxygen microenvironment affects the uptake of nanoparticles in head and neck tumor cells

    Science.gov (United States)

    Chen, Eunice Y.; Hodge, Sasson; Tai, Katherine; Hou, Huagang; Khan, Nadeem; Hoopes, P. Jack; Samkoe, Kimberley S.

    2013-02-01

    Survival of head and neck cancer patients has not improved in several decades despite advances in diagnostic and therapeutic techniques. Tumor hypoxia in head and neck cancers is a critical factor that leads to poor prognosis, resistance to radiation and chemotherapies, and increased metastatic potential. Magnetic nanoparticle hyperthermia (mNPHT) is a promising therapy for hypoxic tumors because nanoparticles (NP) can be directly injected into, or targeted to, hypoxic tumor cells and exposed to alternating magnetic fields (AMF) to induce hyperthermia. Magnetic NPHT can improve therapeutic effectiveness by two modes of action: 1) direct killing of hypoxic tumor cells; and 2) increase in tumor oxygenation, which has the potential to make the tumor more susceptible to adjuvant therapies such as radiation and chemotherapy. Prior studies in breast cancer cells demonstrated that a hypoxic microenvironment diminished NP uptake in vitro; however, mNPHT with intratumoral NP injection in hypoxic tumors increased tumor oxygenation and delayed tumor growth. In this study, head and neck squamous cell carcinoma (HNSCC) cell lines were incubated in normoxic, hypoxic, and hyperoxic conditions with iron oxide NP for 4-72 hours. After incubation, the cells were analyzed for iron uptake by mass spectrometry, Prussian blue staining, and electron microscopy. In contrast to breast cancer cells, uptake of NPs was increased in hypoxic microenvironments as compared to normoxic conditions in HNSCC cells. In future studies, we will confirm the effect of the oxygen microenvironment on NP uptake and efficacy of mNPHT both in vitro and in vivo.

  18. 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...

  19. The effects of capillary transit time heterogeneity (CTH on the cerebral uptake of glucose and glucose analogs:Application to FDG and comparison to oxygen uptake.

    Directory of Open Access Journals (Sweden)

    Hugo Angleys

    2016-10-01

    Full Text Available Glucose is the brain’s principal source of ATP, but the extent to which cerebral glucose consumption (CMRglc is coupled with its oxygen consumption (CMRO2 remains unclear. Measurements of the brain’s oxygen-glucose index OGI=CMRO2/CMRglc suggest that its oxygen uptake largely suffices for oxidative phosphorylation. Nevertheless, during functional activation and in some disease states, brain tissue seemingly produces lactate although cerebral blood flow (CBF delivers sufficient oxygen, so-called aerobic glycolysis. OGI measurements, in turn, are method-dependent in that estimates based on glucose analog uptake depend on the so-called lumped constant (LC to arrive at CMRglc. Capillary transit time heterogeneity (CTH, which is believed to change during functional activation and some disease states, affects the extraction efficacy of oxygen from blood. We developed a three-compartment model of glucose extraction to examine whether CTH also affects glucose extraction into brain tissue. We then combined this model with our previous model of oxygen extraction to examine whether differential glucose and oxygen extraction might favor nonoxidative glucose metabolism under certain conditions. Our model predicts that glucose uptake is largely unaffected by changes in its plasma concentration, while changes in CBF and CTH affect glucose and oxygen uptake to different extents. Accordingly, functional hyperemia facilitates glucose uptake more than oxygen uptake, favoring aerobic glycolysis during enhanced energy demands. Applying our model to glucose analogs, we observe that LC depends on physiological state, with a risk of overestimating relative increases in CMRglc during functional activation by as much as 50%.

  20. Low blood flow at onset of moderate intensity exercise does not limit muscle oxygen uptake

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Mortensen, Stefan Peter; Saltin, Bengt

    2010-01-01

    The effect of low blood flow at onset of moderate intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5 minute one-legged knee-extensor exercise bout (24+/-1 (+/-S.D.) W) without (CON) and with (double blockade; DB) arterial infusion of i....... Additionally, prostanoids and/or NO appear to play important roles in elevating skeletal muscle blood flow in the initial phase of exercise. Key words: Oxygen delivery, oxygen extraction, nitric oxide, prostanoids.......The effect of low blood flow at onset of moderate intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5 minute one-legged knee-extensor exercise bout (24+/-1 (+/-S.D.) W) without (CON) and with (double blockade; DB) arterial infusion...... of inhibitors of nitric oxide synthase (NOS; L-NMMA) and cyclooxygenase (COX; indomethacin) in order to inhibit the synthesis of nitric oxide (NO) and prostanoids, respectively.. Leg blood flow and leg oxygen delivery throughout exercise was 25-50 % lower (P

  1. Meal-induced changes in splanchnic blood flow and oxygen uptake in middle-aged healthy humans

    DEFF Research Database (Denmark)

    Madsen, Jan Lysgård; Søndergaard, SB; Møller, Søren

    2006-01-01

    OBJECTIVE: For decades, the determination of changes in splanchnic blood flow and oxygen uptake after a meal has been used in the management of patients with suspected chronic intestinal ischaemia. However, little is known about the normal meal-induced responses. The aim of the present study...... was therefore to measure the splanchnic blood flow and oxygen uptake before and after a standardized meal in a group of middle-aged normal volunteers. MATERIAL AND METHODS: Splanchnic blood flow and oxygen uptake were determined at baseline and after a 3600-kJ mixed meal in 8 healthy women (50-70 years) and 10...... healthy men (52-76 years). Splanchnic blood flow was measured during hepatic vein catheterization by indirect Fick principle with indocyanine green as the indicator. Splanchnic oxygen uptake was calculated from splanchnic blood flow and the arteriovenous oxygen difference. RESULTS: The meal induced...

  2. 25(OHD3 Levels Relative to Muscle Strength and Maximum Oxygen Uptake in Athletes

    Directory of Open Access Journals (Sweden)

    Książek Anna

    2016-04-01

    Full Text Available Vitamin D is mainly known for its effects on the bone and calcium metabolism. The discovery of Vitamin D receptors in many extraskeletal cells suggests that it may also play a significant role in other organs and systems. The aim of our study was to assess the relationship between 25(OHD3 levels, lower limb isokinetic strength and maximum oxygen uptake in well-trained professional football players. We enrolled 43 Polish premier league soccer players. The mean age was 22.7±5.3 years. Our study showed decreased serum 25(OHD3 levels in 74.4% of the professional players. The results also demonstrated a lack of statistically significant correlation between 25(OHD3 levels and lower limb muscle strength with the exception of peak torque of the left knee extensors at an angular velocity of 150°/s (r=0.41. No significant correlations were found between hand grip strength and maximum oxygen uptake. Based on our study we concluded that in well-trained professional soccer players, there was no correlation between serum levels of 25(OHD3 and muscle strength or maximum oxygen uptake.

  3. Persistent resetting of the cerebral oxygen/glucose uptake ratio by brain activation

    DEFF Research Database (Denmark)

    Madsen, P L; Hasselbalch, S G; Hagemann, L P

    1995-01-01

    fraction of the activation-induced excess glucose uptake. These data confirm earlier reports that brain activation can induce resetting of the cerebral oxygen/glucose consumption ratio, and indicate that the resetting persists for a long period after cerebral activation has been terminated and physiologic......Global cerebral blood flow (CBF), global cerebral metabolic rates for oxygen (CMRO2), and for glucose (CMRglc), and lactate efflux were measured during rest and during cerebral activation induced by the Wisconsin card sorting test. Measurements were performed in healthy volunteers using the Kety......-Schmidt technique. Global CMRO2 was unchanged during cerebral activation, whereas global CBF and global CMRglc both increased by 12%, reducing the molar ratio of oxygen to glucose consumption from 6.0 during baseline conditions to 5.4 during activation. Data obtained in the period following cerebral activation...

  4. Characterization of positron emission tomography hypoxia tracer uptake and tissue oxygenation via electrochemical modeling

    Energy Technology Data Exchange (ETDEWEB)

    Bowen, Stephen R., E-mail: srbowen@wisc.edu [University of Wisconsin School of Medicine and Public Health, Department of Medical Physics, Madison, WI 53706 (United States); Kogel, Albert J. van der [University Medical Centre St. Radboud, Nijmegen (Netherlands); Nordsmark, Marianne [Aarhus University Hospital, Department of Experimental Clinical Oncology, Aarhus (Denmark); Bentzen, Soren M. [University of Wisconsin School of Medicine and Public Health, Department of Medical Physics, Madison, WI 53706 (United States); University of Wisconsin School of Medicine and Public Health, Department of Human Oncology, Clinical Sciences Center, Madison, WI 53792 (United States); Jeraj, Robert [University of Wisconsin School of Medicine and Public Health, Department of Medical Physics, Madison, WI 53706 (United States); University of Wisconsin School of Medicine and Public Health, Department of Human Oncology, Clinical Sciences Center, Madison, WI 53792 (United States); Jozef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia)

    2011-08-15

    Purpose: Unique uptake and retention mechanisms of positron emission tomography (PET) hypoxia tracers make in vivo comparison between them challenging. Differences in imaged uptake of two common hypoxia radiotracers, [{sup 61}Cu]Cu-ATSM and [{sup 18}F]FMISO, were characterized via computational modeling to address these challenges. Materials and Methods: An electrochemical formalism describing bioreductive retention mechanisms of these tracers under steady-state conditions was adopted to relate time-averaged activity concentration to tissue partial oxygen tension (PO{sub 2}), a common metric of hypoxia. Chemical equilibrium constants of product concentration to reactant concentration ratios were determined from free energy changes and reduction potentials of pertinent reactions reported in the literature. Resulting transformation functions between tracer uptake and PO{sub 2} were compared against measured values in preclinical models. Additionally, calculated PO{sub 2} distributions from imaged Cu-ATSM tracer activity concentrations of 12 head and neck squamous cell carcinoma (HNSCC) patients were validated against microelectrode PO{sub 2} measurements in 69 HNSCC patients. Results: Both Cu-ASTM- and FMISO-modeled PO{sub 2} transformation functions were in agreement with preclinical measured values within single-deviation confidence intervals. High correlation (r{sup 2}=0.94, P<.05) was achieved between modeled PO{sub 2} distributions and measured distributions in the patient populations. On average, microelectrode hypoxia thresholds (2.5 and 5.0 mmHg) corresponded to higher Cu-ATSM uptake [2.5 and 2.0 standardized uptake value (SUV)] and lower FMISO uptake (2.0 and 1.4 SUV). Uncertainties in the models were dominated by variations in the estimated specific activity and intracellular acidity. Conclusions: Results indicated that the high dynamic range of Cu-ATSM uptake was representative of a narrow range of low oxygen tension whose values were dependent on

  5. Study of oxygen mass transfer coefficient and oxygen uptake rate in a stirred tank reactor for uranium ore bioleaching

    International Nuclear Information System (INIS)

    Zokaei-Kadijani, S.; Safdari, J.; Mousavian, M.A.; Rashidi, A.

    2013-01-01

    Highlights: ► Mass transfer coefficient does not depend on biomass concentration. ► The pulp density has a negative effect on mass transfer coefficient. ► The pulp density is the unique factor that affects maximum OUR. ► In this work, Neale’s correlation is corrected for prediction of mass transfer coefficient. ► Biochemical reaction is a limiting factor in the uranium bioleaching process. - Abstract: In this work, the volumetric oxygen mass transfer coefficient and the oxygen uptake rate (OUR) were studied for uranium ore bioleaching process by Acidthiobacillus ferrooxidans in a stirred tank reactor. The Box-Bohnken design method was used to study the effect of operating parameters on the oxygen mass transfer coefficient. The investigated factors were agitation speed (rpm), aeration rate (vvm) and pulp density (% weight/volume) of the stirred tank reactor. Analysis of experimental results showed that the oxygen mass transfer coefficient had low dependence on biomass concentration but had higher dependence on the agitation speed, aeration rate and pulp density. The obtained biological enhancement factors were equal to ones in experiments. On the other hand, the obtained values for Damkohler number (Da < 0.468) indicated that the process was limited by the biochemical reaction rate. Experimental results obtained for oxygen mass transfer coefficient were correlated with the empirical relations proposed by Garcia-Ochoa and Gomez (2009) and Neale and Pinches (1994). Due to the high relative error in the correlation of Neale and Pinches, that correlation was corrected and the coefficient of determination was calculated to be 89%. The modified correlation has been obtained based on a wide range of operating conditions, which can be used to determine the mass transfer coefficient in a bioreactor

  6. On the mechanisms that limit oxygen uptake during exercise in acute and chronic hypoxia: role of muscle mass

    DEFF Research Database (Denmark)

    Calbet, José A L; Rådegran, Göran; Boushel, Robert

    2009-01-01

    (dye dilution with Cardio-green), leg blood flow (thermodilution), intra-arterial blood pressure and femoral arterial-to-venous differences in blood gases were determined in nine lowlanders studied during incremental exercise using a large (two-legged cycle ergometer exercise: Bike) and a small (one...... altitude acclimatization. Acclimatization improved Bike peak exercise Pa,O2 from 34 +/- 1 in AH to 45 +/- 1 mmHg in CH(P Bike. Acute hypoxia resulted in reduction...... of systemic O2 delivery (46 and 21%) and leg O2 delivery (47 and 26%) during Bike and Knee, respectively, almost matching the corresponding reduction in VO2,peak. Altitude acclimatization restored fully peak systemic and leg O(2) delivery in CH (2.69 +/- 0.27 and 1.28 +/- 0.11 l min(-1), respectively) to sea...

  7. Effects of oxygen delivery, dietary nitrate, intensified training and prior exercise on oxygen uptake kinetics and performance in humans

    DEFF Research Database (Denmark)

    Christensen, Peter Møller

    benefits from supplementing with nitrate to improve exercise efficiency and performance in endurance trained subjects. Furthermore it appears difficult to improve VO2 kinetics with intensified training in trained athletes; however intense exercise can amplify the VO2 response during subsequent high......In response to an increase in the metabolic demand the oxygen uptake (VO2) increases in an exponential fashion in exercising muscles and stabilizes after 1-2 min eventually reaching a plateau or steady state where the energy demand is matched by the l vel of VO2. VO2 kinetics describes the distinct...... phases of the VO2 response at the onset of exercise. Fast VO2 kinetics are considered to be beneficial in intense endurance sports with competitions lasting ~2-8 min, whereas low VO2 at steady state (high efficiency) is considered beneficial especially in events of longer duration. To improve...

  8. Fermentation process using specific oxygen uptake rates as a process control

    Science.gov (United States)

    Van Hoek, Pim [Minnetonka, MN; Aristidou, Aristos [Maple Grove, MN; Rush, Brian [Minneapolis, MN

    2011-05-10

    Specific oxygen uptake (OUR) is used as a process control parameter in fermentation processes. OUR is determined during at least the production phase of a fermentation process, and process parameters are adjusted to maintain the OUR within desired ranges. The invention is particularly applicable when the fermentation is conducted using a microorganism having a natural PDC pathway that has been disrupted so that it no longer functions. Microorganisms of this sort often produce poorly under strictly anaerobic conditions. Microaeration controlled by monitoring OUR allows the performance of the microorganism to be optimized.

  9. Pain severity is associated with muscle strength and peak oxygen uptake in adults with fibromyalgia

    Directory of Open Access Journals (Sweden)

    Hooten WM

    2014-05-01

    Full Text Available W Michael Hooten,1,2 Jolene M Smith,3 Jason S Eldrige,1 David A Olsen,3 W David Mauck,1 Susan M Moeschler11Department of Anesthesiology, 2Department of Psychiatry and Psychology, Mayo Clinic College of Medicine, 3Mayo School of Graduate Medical Education, Rochester, MN, USABackground: The associations between pain, lower extremity strength, and aerobic conditioning have not been widely investigated in adults with fibromyalgia (FM. The principle objective of this study was to investigate the relationship between pain severity and knee strength in patients seeking treatment for FM. A secondary objective was to investigate the relationship between pain scores and aerobic conditioning.Methods: Three measures of knee strength (isokinetic extensor, isokinetic flexor, isometric extensor were quantified in the dominant leg of 69 adults with FM using a dynamometer at speeds of 60 degrees per second (60°/s and 180°/s. Peak oxygen uptake (VO2 was assessed using a cycle ergometer, and pain was assessed using the pain severity subscale of the Multidimensional Pain Inventory.Results: In univariable linear regression analyses using pain severity as the dependent variable, lesser values of isokinetic knee extensor strength at 60°/s (P=0.041 and 180°/s (P=0.010, isokinetic knee flexor strength at 60°/s (P=0.028 and 180°/s (P=0.003, and peak VO2 uptake (P=0.031 were predictive of greater pain severity scores. In multiple variable linear regression models adjusted for age, sex, body mass index, and opioid use, the following associations retained statistical significance; isokinetic knee extensor strength at 60°/s (P=0.020 and 180°/s (P=0.003, isokinetic knee flexor strength at 60°/s (P=0.015 and 180°/s (P=0.001, and peak VO2 uptake (P=0.014. However, no significant associations were found between pain severity and isometric knee extensor strength.Conclusion: The main findings from this study were that lesser values of isokinetic knee strength and peak VO

  10. Exercise training induces similar elevations in the activity of oxoglutarate dehydrogenase and peak oxygen uptake in the human quadriceps muscle

    DEFF Research Database (Denmark)

    Blomstrand, Eva; Krustrup, Peter; Søndergaard, Hans

    2011-01-01

    During exercise involving a small muscle mass, peak oxygen uptake is thought to be limited by peripheral factors, such as the degree of oxygen extraction from the blood and/or mitochondrial oxidative capacity. Previously, the maximal activity of the Krebs cycle enzyme oxoglutarate dehydrogenase has...

  11. Effect of ship locking on sediment oxygen uptake in impounded rivers

    DEFF Research Database (Denmark)

    Lorke, A.; McGinnis, D. F.; Maeck, A.

    2012-01-01

    In the majority of large river systems, flow is regulated and/or otherwise affected by operational and management activities, such as ship locking. The effect of lock operation on sediment-water oxygen fluxes was studied within a 12.9 km long impoundment at the Saar River (Germany) using eddy....... Additional means by which the oxygen budget of the impoundment is affected by lock-induced flow variations are discussed. Citation: Lorke, A., D. F. McGinnis, A. Maeck, and H. Fischer (2012), Effect of ship locking on sediment oxygen uptake in impounded rivers, Water Resour. Res., 48, W12514, doi: 10....... These wave-induced flow variations cause variations in sediment-water oxygen fluxes. While the mean flux during time periods without lock operation was 0.5 +/- 0.1 g m(-2) d(-1), it increased by about a factor of 2 to 1.0 +/- 0.5 g m(-2) d(-1) within time periods with ship locking. Following the daily...

  12. 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.

  13. Effect of ZnO nanoparticles in the oxygen uptake during aerobic wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Cervantes-Avilés, Pabel; Brito, Elcia M. S. [University of Guanajuato, Engineering Division, Department of Civil Engineering & Environmental Engineering (Mexico); Duran, Robert [Université de Pau et des Pays de l’Adour, Equipe Environment et Microbiologie (France); Martínez, Arodí Bernal; Cuevas-Rodríguez, Germán, E-mail: german28@ugto.mx [University of Guanajuato, Engineering Division, Department of Civil Engineering & Environmental Engineering (Mexico)

    2016-07-15

    The increased use of ZnO nanoparticles (NPs) in everyday products indicates the importance of studying NPs release to the wastewater and its possible effect on biological process for wastewater treatment. Therefore, the aim of this work was to study the effect of the presence of ZnO NPs in aerobic wastewater treatment. The results indicated that the oxygen uptake rate of microorganisms is inhibited for concentrations higher than 473 mg L{sup −1} of ZnO NPs. The diversity of microorganisms involved in wastewater treatment was reduced in presence of ZnO NPs. Related to morphological interaction between ZnO NPs and suspended biomass, physical damage in flocs structure were observed in presence of ZnO NPs. However, the internalization of Zn compounds in microorganisms not presented mechanical damage in the membrane cell. These findings suggest that inhibition in oxygen uptake was caused for negative effect that ZnO NPs induces in aerobic microorganisms involved in wastewater treatment.

  14. Influence of Prolonged Spaceflight on Heart Rate and Oxygen Uptake Kinetics

    Science.gov (United States)

    Hoffmann, U.; Moore, A.; Drescher, U.

    2013-02-01

    During prolonged spaceflight, physical training is used to minimize cardiovascular deconditioning. Measurement of the kinetics of cardiorespiratory parameters, in particular the kinetic analysis of heart rate, respiratory and muscular oxygen uptake, provides useful information with regard to the efficiency and regulation of the cardiorespiratory system. Practically, oxygen uptake kinetics can only be measured at the lung site (V’O2 resp). The dynamics of V’O2 resp, however, is not identical with the dynamics at the site of interest: skeletal muscle. Eight Astronauts were tested pre- and post-flight using pseudo random binary workload changes between 30 and 80 W. Their kinetic responses of heart rate, respiratory as well as muscular V’O2 kinetics were estimated by using time-series analysis. Statistical analysis revealed that the kinetic responses of respiratory as well as muscular V’O2 kinetics are slowed post-flight than pre-flight. Heart rate seems not to be influenced following flight. The influence of other factors (e. g. astronauts’ exercise training) may impact these parameters and is an area for future studies.

  15. Photoluminescent Gold Nanoclusters in Cancer Cells: Cellular Uptake, Toxicity, and Generation of Reactive Oxygen Species.

    Science.gov (United States)

    Matulionyte, Marija; Dapkute, Dominyka; Budenaite, Laima; Jarockyte, Greta; Rotomskis, Ricardas

    2017-02-10

    In recent years, photoluminescent gold nanoclusters have attracted considerable interest in both fundamental biomedical research and practical applications. Due to their ultrasmall size, unique molecule-like optical properties, and facile synthesis gold nanoclusters have been considered very promising photoluminescent agents for biosensing, bioimaging, and targeted therapy. Yet, interaction of such ultra-small nanoclusters with cells and other biological objects remains poorly understood. Therefore, the assessment of the biocompatibility and potential toxicity of gold nanoclusters is of major importance before their clinical application. In this study, the cellular uptake, cytotoxicity, and intracellular generation of reactive oxygen species (ROS) of bovine serum albumin-encapsulated (BSA-Au NCs) and 2-(N-morpholino) ethanesulfonic acid (MES)capped photoluminescent gold nanoclusters (Au-MES NCs) were investigated. The results showed that BSA-Au NCs accumulate in cells in a similar manner as BSA alone, indicating an endocytotic uptake mechanism while ultrasmall Au-MES NCs were distributed homogeneously throughout the whole cell volume including cell nucleus. The cytotoxicity of BSA-Au NCs was negligible, demonstrating good biocompatibility of such BSA-protected Au NCs. In contrast, possibly due to ultrasmall size and thin coating layer, Au-MES NCs exhibited exposure time-dependent high cytotoxicity and higher reactivity which led to highly increased generation of reactive oxygen species. The results demonstrate the importance of the coating layer to biocompatibility and toxicity of ultrasmall photoluminescent gold nanoclusters.

  16. Photoluminescent Gold Nanoclusters in Cancer Cells: Cellular Uptake, Toxicity, and Generation of Reactive Oxygen Species

    Directory of Open Access Journals (Sweden)

    Marija Matulionyte

    2017-02-01

    Full Text Available In recent years, photoluminescent gold nanoclusters have attracted considerable interest in both fundamental biomedical research and practical applications. Due to their ultrasmall size, unique molecule-like optical properties, and facile synthesis gold nanoclusters have been considered very promising photoluminescent agents for biosensing, bioimaging, and targeted therapy. Yet, interaction of such ultra-small nanoclusters with cells and other biological objects remains poorly understood. Therefore, the assessment of the biocompatibility and potential toxicity of gold nanoclusters is of major importance before their clinical application. In this study, the cellular uptake, cytotoxicity, and intracellular generation of reactive oxygen species (ROS of bovine serum albumin-encapsulated (BSA-Au NCs and 2-(N-morpholino ethanesulfonic acid (MEScapped photoluminescent gold nanoclusters (Au-MES NCs were investigated. The results showed that BSA-Au NCs accumulate in cells in a similar manner as BSA alone, indicating an endocytotic uptake mechanism while ultrasmall Au-MES NCs were distributed homogeneously throughout the whole cell volume including cell nucleus. The cytotoxicity of BSA-Au NCs was negligible, demonstrating good biocompatibility of such BSA-protected Au NCs. In contrast, possibly due to ultrasmall size and thin coating layer, Au-MES NCs exhibited exposure time-dependent high cytotoxicity and higher reactivity which led to highly increased generation of reactive oxygen species. The results demonstrate the importance of the coating layer to biocompatibility and toxicity of ultrasmall photoluminescent gold nanoclusters.

  17. Effect of race distance on muscle oxygenation in short-track speed skating.

    Science.gov (United States)

    Hesford, Catherine M; Laing, Stewart; Cardinale, Marco; Cooper, Chris E

    2013-01-01

    Previous work identified an asymmetry in tissue desaturation changes in the left and right quadriceps muscles during on-ice skating at maximal speed in males. The effect of changing race distance on the magnitude of desaturation or leg asymmetry is unknown. Six elite male skaters (age = 23 ± 1.8 yr, height = 1.8 ± 0.1 m, mass = 80.1 ± 5.7 kg, midthigh skinfold thickness = 7 ± 2 mm) and four elite female skaters (age = 21 ± 4 yr, height = 1.6 ± 0.1 m, mass = 65.2 ± 4.3 kg, midthigh skinfold thickness = 10 ± 1 mm) were studied. Subjects completed time trials over three race distances. Blood lactate concentration and O2 uptake measurements were combined with near-infrared spectroscopy measures of muscle oxygenation (TSI) and blood volume (tHb) in the right and left vastus lateralis. Neither race distance nor gender had a significant effect on the magnitude of maximal muscle desaturation (ΔTSI(max)). Pattern of local changes in tHb during individual laps was dependent upon subtle differences in skating technique used for the different race distances. Linear regression analysis revealed asymmetry between the right and left leg desaturation in males during the final stages of each race distance, but not in females. At all race distances, local muscle desaturation reached maximal values much more quickly than global VO(2peak). The use of wearable near-infrared spectroscopy devices enabled measurement of muscle oxygenation during competitive race simulation, thus providing unique insight into the effects of velocity and technique changes on local muscle oxygenation. This may have implications for training and race pacing in speed skating.

  18. Gymnasium-based unsupervised exercise maintains benefits in oxygen uptake kinetics obtained following supervised training in type 2 diabetes.

    Science.gov (United States)

    Macananey, Oscar; O'Shea, Donal; Warmington, Stuart A; Green, Simon; Egaña, Mikel

    2012-08-01

    Supervised exercise (SE) in patients with type 2 diabetes improves oxygen uptake kinetics at the onset of exercise. Maintenance of these improvements, however, has not been examined when supervision is removed. We explored if potential improvements in oxygen uptake kinetics following a 12-week SE that combined aerobic and resistance training were maintained after a subsequent 12-week unsupervised exercise (UE). The involvement of cardiac output (CO) in these improvements was also tested. Nineteen volunteers with type 2 diabetes were recruited. Oxygen uptake kinetics and CO (inert gas rebreathing) responses to constant-load cycling at 50% ventilatory threshold (V(T)), 80% V(T), and mid-point between V(T) and peak workload (50% Δ) were examined at baseline (on 2 occasions) and following each 12-week training period. Participants decided to exercise at a local gymnasium during the UE. Thirteen subjects completed all the interventions. The time constant of phase 2 of oxygen uptake was significantly faster (p exercise maintained benefits in oxygen uptake kinetics obtained during a supervised exercise in subjects with diabetes, and these benefits were associated with a faster dynamic response of heart rate after training.

  19. VO(2peak), myocardial hypertrophy, and myocardial blood flow in endurance-trained men.

    Science.gov (United States)

    Laaksonen, Marko S; Heinonen, Ilkka; Luotolahti, Matti; Knuuti, Juhani; Kalliokoski, Kari K

    2014-08-01

    Endurance training induces cardiovascular and metabolic adaptations, leading to enhanced endurance capacity and exercise performance. Previous human studies have shown contradictory results in functional myocardial vascular adaptations to exercise training, and we hypothesized that this may be related to different degrees of hypertrophy in the trained heart. We studied the interrelationships between peak aerobic power (V˙O2peak), myocardial blood flow (MBF) at rest and during adenosine-induced vasodilation, and parameters of myocardial hypertrophy in endurance-trained (ET, n = 31) and untrained (n = 17) subjects. MBF and myocardial hypertrophy were studied using positron emission tomography and echocardiography, respectively. Both V˙O2peak (P negatively with adenosine-stimulated MBF, but when LV mass was taken into account as a partial correlate, this correlation disappeared. The present results show that increased LV mass in ET subjects explains the reduced hyperemic myocardial perfusion in this subject population and suggests that excessive LV hypertrophy has negative effect on cardiac blood flow capacity.

  20. Hydrogen uptake in alumina thin films synthesized from an aluminum plasma stream in an oxygen ambient

    International Nuclear Information System (INIS)

    Schneider, J.M.; Anders, A.; Hjoervarsson, B.; Petrov, I.; Macak, K.; Helmersson, U.; Sundgren, J.

    1999-01-01

    We describe the hydrogen uptake during the synthesis of alumina films from H 2 O present in the high vacuum gas background. The hydrogen concentration in the films was determined by the 1 H( 15 N,αγ) 12 C nuclear resonance reaction. Furthermore, we show the presence of hydrogen ions in the plasma stream by time-of-flight mass spectrometry. The hydrogen content increased in both the film and the plasma stream, as the oxygen partial pressure was increased. On the basis of these measurements and thermodynamic considerations, we suggest that an aluminum oxide hydroxide compound is formed, both on the cathode surface as well as in the film. The large scatter in the data reported in the literature for refractive index and chemical stability of alumina thin films can be explained on the basis of the suggested aluminum oxide hydroxide formation. copyright 1999 American Institute of Physics

  1. Commonly used reference values underestimate oxygen uptake in healthy, 50-year-old Swedish women.

    Science.gov (United States)

    Genberg, M; Andrén, B; Lind, L; Hedenström, H; Malinovschi, A

    2018-01-01

    Cardiopulmonary exercise testing (CPET) is the gold standard among clinical exercise tests. It combines a conventional stress test with measurement of oxygen uptake (V O 2 ) and CO 2 production. No validated Swedish reference values exist, and reference values in women are generally understudied. Moreover, the importance of achieved respiratory exchange ratio (RER) and the significance of breathing reserve (BR) at peak exercise in healthy individuals are poorly understood. We compared V O 2 at maximal load (peakV O 2 ) and anaerobic threshold (V O 2@ AT ) in healthy Swedish individuals with commonly used reference values, taking gender into account. Further, we analysed maximal workload and peakV O 2 with regard to peak RER and BR. In all, 181 healthy, 50-year-old individuals (91 women) performed CPET. PeakV O 2 was best predicted using Jones et al. (100·5%), while SHIP reference values underestimated peakV O 2 most: 112·5%. Furthermore, underestimation of peakV O 2 in women was found for all studied reference values (P 1·1 (2 328·7 versus 2 176·7 ml min -1 , P = 0·11). Lower BR (≤30%) related to significantly higher peakV O 2 (Pvalues underestimated oxygen uptake in women. No evidence for demanding RER > 1·1 in healthy individuals was found. A lowered BR is probably a normal response to higher workloads in healthy individuals. © 2016 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  2. A fast-start pacing strategy speeds pulmonary oxygen uptake kinetics and improves supramaximal running performance.

    Directory of Open Access Journals (Sweden)

    Tiago Turnes

    Full Text Available The focus of the present study was to investigate the effects of a fast-start pacing strategy on running performance and pulmonary oxygen uptake (VO2 kinetics at the upper boundary of the severe-intensity domain. Eleven active male participants (28±10 years, 70±5 kg, 176±6 cm, 57±4 mL/kg/min visited the laboratory for a series of tests that were performed until exhaustion: 1 an incremental test; 2 three laboratory test sessions performed at 95, 100 and 110% of the maximal aerobic speed; 3 two to four constant speed tests for the determination of the highest constant speed (HS that still allowed achieving maximal oxygen uptake; and 4 an exercise based on the HS using a higher initial speed followed by a subsequent decrease. To predict equalized performance values for the constant pace, the relationship between time and distance/speed through log-log modelling was used. When a fast-start was utilized, subjects were able to cover a greater distance in a performance of similar duration in comparison with a constant-pace performance (constant pace: 670 m±22%; fast-start: 683 m±22%; P = 0.029; subjects also demonstrated a higher exercise tolerance at a similar average speed when compared with constant-pace performance (constant pace: 114 s±30%; fast-start: 125 s±26%; P = 0.037. Moreover, the mean VO2 response time was reduced after a fast start (constant pace: 22.2 s±28%; fast-start: 19.3 s±29%; P = 0.025. In conclusion, middle-distance running performances with a duration of 2-3 min are improved and VO2 response time is faster when a fast-start is adopted.

  3. Effect of oral propranolol on splanchnic oxygen uptake and haemodynamics in patients with cirrhosis

    DEFF Research Database (Denmark)

    Bendtsen, Flemming; Henriksen, Jens Henrik; Becker, Povl Ulrik

    1987-01-01

    .01), azygos venous oxygen saturation (76 vs. 67%, P less than 0.05), ICG clearance (263 vs. 226 ml/min, P less than 0.01), wedged-to-free hepatic vein pressure (16 vs. 13.5 mm Hg, P less than 0.01), hepatic blood flow (1.18 vs. 0.78 l/min, P less than 0.01), cardiac index (3.42 vs. 2.53 l/min . min 2, P less...... mg propranolol. All patients underwent hepatic vein catheterization and had a primed continuous intravenous infusion of ICG. Azygos vein catheterization was performed in six patients. Splanchnic (hepatic-intestinal) oxygen uptake (median control 68 ml/min vs. beta-blockade 56 ml/min, P less than 0...... than 0.01), and heart rate (72 vs. 56 beats per min, P less than 0.01) decreased significantly after oral beta-blockade. The hepatic extraction ratio of ICG increased significantly (0.32 vs. 0.45, P less than 0.01), whereas estimated 'intrinsic' ICG clearance (289 vs. 300 ml/min, n.s.), arterial blood...

  4. Sex differences in the oxygen delivery, extraction, and uptake during moderate-walking exercise transition.

    Science.gov (United States)

    Beltrame, Thomas; Villar, Rodrigo; Hughson, Richard L

    2017-09-01

    Previous studies in children and older adults demonstrated faster oxygen uptake (V̇O 2 ) kinetics in males compared with females, but young healthy adults have not been studied. We hypothesized that young men would have faster aerobic system dynamics in response to the onset of exercise than women. Interactions between oxygen supply and utilization were characterized by the dynamics of V̇O 2 , deoxyhemoglobin (HHb), tissue saturation index (TSI), cardiac output (Q̇), and calculated arteriovenous O 2 difference (a-vO 2 diff ) in women and men. Eighteen healthy active young women and men (9 of each sex) with similar aerobic fitness levels volunteered for this study. Participants performed an incremental cardiopulmonary treadmill exercise test and 3 moderate-intensity treadmill exercise tests (at 80% V̇O 2 of gas exchange threshold). Data related to the moderate exercise were submitted to exponential data modelling to obtain parameters related to the aerobic system dynamics. The time constants of V̇O 2 , a-vO 2 diff , HHb, and TSI (30 ± 6, 29 ± 1, 16 ± 1, and 15 ± 2 s, respectively) in women were statistically (p < 0.05) faster than the time constants in men (42 ± 10, 49 ± 21, 19 ± 3, and 20 ± 4 s, respectively). Although Q̇ dynamics were not statistically different (p = 0.06) between groups, there was a trend to slower Q̇ dynamics in men corresponding with the slower V̇O 2 kinetics. These results indicated that the peripheral and pulmonary oxygen extraction dynamics were remarkably faster in women. Thus, contrary to the hypothesis, V̇O 2 dynamics measured at the mouth at the onset of submaximal treadmill walking were faster in women compared with men.

  5. Machine learning and statistical methods for the prediction of maximal oxygen uptake: recent advances

    Directory of Open Access Journals (Sweden)

    Abut F

    2015-08-01

    Full Text Available Fatih Abut, Mehmet Fatih AkayDepartment of Computer Engineering, Çukurova University, Adana, TurkeyAbstract: Maximal oxygen uptake (VO2max indicates how many milliliters of oxygen the body can consume in a state of intense exercise per minute. VO2max plays an important role in both sport and medical sciences for different purposes, such as indicating the endurance capacity of athletes or serving as a metric in estimating the disease risk of a person. In general, the direct measurement of VO2max provides the most accurate assessment of aerobic power. However, despite a high level of accuracy, practical limitations associated with the direct measurement of VO2max, such as the requirement of expensive and sophisticated laboratory equipment or trained staff, have led to the development of various regression models for predicting VO2max. Consequently, a lot of studies have been conducted in the last years to predict VO2max of various target audiences, ranging from soccer athletes, nonexpert swimmers, cross-country skiers to healthy-fit adults, teenagers, and children. Numerous prediction models have been developed using different sets of predictor variables and a variety of machine learning and statistical methods, including support vector machine, multilayer perceptron, general regression neural network, and multiple linear regression. The purpose of this study is to give a detailed overview about the data-driven modeling studies for the prediction of VO2max conducted in recent years and to compare the performance of various VO2max prediction models reported in related literature in terms of two well-known metrics, namely, multiple correlation coefficient (R and standard error of estimate. The survey results reveal that with respect to regression methods used to develop prediction models, support vector machine, in general, shows better performance than other methods, whereas multiple linear regression exhibits the worst performance

  6. Hydraulic Permeability of Resorcinol-Formaldehyde Ion-Exchange Resin - Effects of Oxygen Uptake and Radiation

    International Nuclear Information System (INIS)

    Taylor, Paul Allen

    2009-01-01

    An ion-exchange process, using spherical resorcinol-formaldehyde (RF) resin is the baseline process for removing cesium from the dissolved salt solution in the high-level waste tanks at the U.S. Department of Energy's (DOE) Hanford site in Washington State. The RF resin is also being evaluated for use in the proposed Small Column Ion Exchange (SCIX) system, which is an alternative treatment option at DOE's Savannah River Site (SRS)in South Carolina. Testing at ORNL will determine the impact of radiation exposure and oxygen uptake by the RF resin on the hydraulic permeability of the resin. Samples of the resin will be removed periodically to measure physical properties (bead size and compressibility) and cesium capacity. The proposed full-scale treatment system at Hanford, the Waste Treatment Plant (WTP), will use an ion-exchange column containing nominally 680 gal of resin, which will treat 30 gpm of waste solution. The ion-exchange column is designed for a typical pressure drop of 6 psig, with a maximum of 9.7 psig. The lab-scale column is 3-in. clear PVC pipe and is prototypic of the proposed Hanford column. The fluid velocity in the lab-scale test will be much higher than for the full-scale column, in order to generate the maximum pressure drop expected in that column (9.7 psig). The frictional drag from this high velocity will produce similar forces on the resin in the lab-scale column as would be expected at the bottom of the full-scale column. The chemical changes in the resin caused by radiation exposure and oxygen uptake are expected to cause physical changes in the resin that could reduce the bed porosity and reduce the hydraulic permeability of the resin bed. These changes will be monitored by measuring the pressure drop through the lab-scale column and by measuring the physical properties of samples of the resin. The test loop with the lab-scale column is currently being fabricated, and operation will start by late May. Testing will be completed by the

  7. The influence of different space-related physiological variations on exercise capacity determined by oxygen uptake kinetics

    Science.gov (United States)

    Stegemann, J.

    Oxygen uptake kinetics, following defined variations of work load changes allow to estimate the contribution of aerob and anaerob energy supply which is the base for determining work capacity. Under the aspect of long duration missions with application of adequate dosed countermeasures, a reliable estimate of the astronaut's work capacity is important to adjust the necessary inflight training. Since the kinetics of oxygen uptake originate in the working muscle group itself, while measurements are performed at the mouth, various influences within the oxygen transport system might disturb the determinations. There are not only detraining effects but also well-known other influences, such as blood- and fluid shifts induced by weightlessness. They might have an impact on the circulatory system. Some of these factors have been simulated by immersion, blood donation, and changing of the body position.

  8. 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.

  9. Comparison of the oxygen uptake kinetics of club and olympic champion rowers.

    Science.gov (United States)

    Ingham, Stephen A; Carter, Helen; Whyte, Gregory P; Doust, Jonathan H

    2007-05-01

    To test the hypothesis that elite rowers would possess a faster, more economic oxygen uptake response than club standard rowers. Eight Olympic champion (ELITE) rowers were compared with a cohort of eight club standard (CLUB) rowers. Participants completed a progressive exercise test to exhaustion, repeated 6-min moderate and heavy square-wave transitions, and a maximal 2000-m ergometer time trial. The time constant (tau) of the primary component (PC) was faster for the ELITE group compared with CLUB for moderate-intensity (13.9 vs 19.4 s, P = 0.02) and heavy-intensity (18.7 vs 22.4 s, P = 0.005) exercise. ELITE rowers consumed less oxygen for moderate (14.2 vs 15.6 mL x min(-1) x W(-1); P = 0.009) and heavy (12.1 vs 13.7 mL x min(-1) x W(-1); P = 0.01) exercise. A greater absolute slow component was observed in the ELITE group (P = 0.009), but no differences were noted when the slow component was expressed relative to work rate performed (P = 0.14). Intergroup correlation with time trial performance speed was significant for tauPC during heavy-intensity exercise (r = -0.59, P = 0.02). Compared with CLUB rowers, the shorter time constant response and greater economy observed in ELITE rowers may suggest advantageous adjustment of oxidative processes from rest to work. Training status or performance level do not seem to be associated with a smaller slow component when comparing CLUB and ELITE oarsmen.

  10. Machine learning and statistical methods for the prediction of maximal oxygen uptake: recent advances.

    Science.gov (United States)

    Abut, Fatih; Akay, Mehmet Fatih

    2015-01-01

    Maximal oxygen uptake (VO2max) indicates how many milliliters of oxygen the body can consume in a state of intense exercise per minute. VO2max plays an important role in both sport and medical sciences for different purposes, such as indicating the endurance capacity of athletes or serving as a metric in estimating the disease risk of a person. In general, the direct measurement of VO2max provides the most accurate assessment of aerobic power. However, despite a high level of accuracy, practical limitations associated with the direct measurement of VO2max, such as the requirement of expensive and sophisticated laboratory equipment or trained staff, have led to the development of various regression models for predicting VO2max. Consequently, a lot of studies have been conducted in the last years to predict VO2max of various target audiences, ranging from soccer athletes, nonexpert swimmers, cross-country skiers to healthy-fit adults, teenagers, and children. Numerous prediction models have been developed using different sets of predictor variables and a variety of machine learning and statistical methods, including support vector machine, multilayer perceptron, general regression neural network, and multiple linear regression. The purpose of this study is to give a detailed overview about the data-driven modeling studies for the prediction of VO2max conducted in recent years and to compare the performance of various VO2max prediction models reported in related literature in terms of two well-known metrics, namely, multiple correlation coefficient (R) and standard error of estimate. The survey results reveal that with respect to regression methods used to develop prediction models, support vector machine, in general, shows better performance than other methods, whereas multiple linear regression exhibits the worst performance.

  11. Relationship between changes in haemoglobin mass and maximal oxygen uptake after hypoxic exposure.

    Science.gov (United States)

    Saunders, Philo U; Garvican-Lewis, Laura A; Schmidt, Walter F; Gore, Christopher J

    2013-12-01

    Endurance athletes have been using altitude training for decades to improve near sea-level performance. The predominant mechanism is thought to be accelerated erythropoiesis increasing haemoglobin mass (Hb(mass)) resulting in a greater maximal oxygen uptake (VO₂(max)). Not all studies have shown a proportionate increase in VO₂(max) as a result of increased Hb(mass). The aim of this study was to determine the relationship between the two parameters in a large group of endurance athletes after altitude training. 145 elite endurance athletes (94 male and 51 female) who participated in various altitude studies as altitude or control participants were used for the analysis. Participants performed Hb(mass) and VO₂(max) testing before and after intervention. For the pooled data, the correlation between per cent change in Hb(mass) and per cent change in VO₂(max) was significant (pstatistical power, we conclude that altitude training of endurance athletes will result in an increase in VO₂(max) of more than half the magnitude of the increase in Hb(mass), which supports the use of altitude training by athletes. But race performance is not perfectly related to relative VO₂(max), and other non-haematological factors altered from altitude training, such as running economy and lactate threshold, may also be beneficial to performance.

  12. Root porosity and radial oxygen loss related to arsenic tolerance and uptake in wetland plants

    International Nuclear Information System (INIS)

    Li, H.; Ye, Z.H.; Wei, Z.J.; Wong, M.H.

    2011-01-01

    The rates of radial oxygen loss (ROL), root porosity, concentrations of arsenic (As), iron (Fe) and manganese (Mn) in shoot and root tissues and on root surfaces, As tolerances, and their relationships in different wetland plants were investigated based on a hydroponic experiment (control, 0.8, 1.6 mg As L -1 ) and a soil pot trail (control, 60 mg As kg -1 ). The results revealed that wetland plants showed great differences in root porosity (9-64%), rates of ROL (55-1750 mmo1 O 2 kg -1 root d.w. d -1 ), As uptake (e.g., 8.8-151 mg kg -1 in shoots in 0.8 mg As L -1 treatment), translocation factor (2.1-47% in 0.8 mg As L -1 ) and tolerance (29-106% in 0.8 mg As L -1 ). Wetland plants with higher rates of ROL and root porosity tended to form more Fe/Mn plaque, possess higher As tolerance, higher concentrations of As on root surfaces and a lower As translocation factor so decreasing As toxicity. - Research highlights: → There is significant correlation between the porosity of roots and rates of ROL. → The rates of ROL are significantly correlated with tolerance indices and concentrations of As, Fe, Mn on root surface. → The rates of ROL is negatively correlated with As translocation factor. - Wetland plants with high rates of ROL tended to form more Fe plaque on root surfaces and possess higher As tolerance.

  13. Effect of maximal oxygen uptake and different forms of physical training on serum lipoproteins.

    Science.gov (United States)

    Schnabel, A; Kindermann, W

    1982-01-01

    260 well trained male sportsmen between 17 and 30 years of age participating in a variety of events were examined for total serum cholesterol and lipoprotein cholesterol and compared with 37 moderately active leisure-time sportsmen and 20 sedentary controls of similar ages and sex. Lipoprotein cholesterol distribution was determined by quantitative electrophoresis. Mean HDL-cholesterol increased progressively from the mean of the sedentary control to the mean of the long-distance runners, indicating a graded effect of physical activity on HDL-cholesterol. In all sporting groups mean LDL-cholesterol tended to be lower than in the controls, no association between LDL-cholesterol and form of training being apparent. Except for the long-distance runners, all sporting groups tended to be lower in total cholesterol than the controls. The HDL-/total cholesterol and LDL/HDL ratios yielded a better discrimination between the physically active and inactive than the HDL-cholesterol alone. Significant positive correlations with maximal oxygen uptake and roentgenologically determined heart volume were found for HDL-cholesterol and HDL-/total cholesterol, and negative ones for LDL/HDL. Differences in the regressions among subsets made up of sporting groups under different physical demands suggest a positive relationship between lipoprotein distribution and the magnitude of the trained muscle mass.

  14. The effect of caffeine on maximal oxygen uptake and vertical jump performance in male basketball players.

    Science.gov (United States)

    Tucker, Matthew A; Hargreaves, Jill M; Clarke, Jenny C; Dale, Darren L; Blackwell, Gavin J

    2013-02-01

    This study investigated whether performance enhancement from caffeine described by other researchers transfers to male basketball players. The effects of caffeine ingestion were studied in a maximal-effort test on a treadmill that was followed by a vertical-jump test. Five elite-level male basketball players completed a graded treadmill test that measured maximal oxygen uptake, blood lactate profiles, respiratory exchange ratio, and rating of perceived exertion at each 3-minute stage. After a 15-minute warm-down, the subjects performed 10 vertical rebound jumps. Each subject completed the test twice--once with a 3 mg·kg(-1) of body weight dose of caffeine and once with a placebo, with the dosage administered 60 minutes before commencement of exercise. The test was thus administered according to a double-blind protocol. No substantial trends were found between caffeine and control trials, regardless of trial order. The study showed that the specified dosage had negligible effects on the players' power and endurance performance and had no efficacy as an ergogenic aid for male basketball players.

  15. 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

  16. Physiological background of the change point in VO2 and the slow component of oxygen uptake kinetics.

    Science.gov (United States)

    Zoładź, J A; Korzeniewski, B

    2001-06-01

    It is generally believed that oxygen uptake during incremental exercise--until VO2max, increases linearly with power output (see eg. Astrand & Rodahl, 1986). On the other hand, it is well established that the oxygen uptake reaches a steady state only during a low power output exercise, but during a high power output exercise, performed above the lactate threshold (LT), the oxygen uptake shows a continuous increase until the end of the exercise. This effect has been called the slow component of VO2 kinetics (Whipp & Wasserman, 1972). The presence of a slow component in VO2 kinetics implies that during an incremental exercise test, after the LT has been exceeded, the VO2 to power output relationship has to become curvilinear. Indeed, it has recently been shown that during the incremental exercise, the exceeding of the power output, at which blood lactate begins to accumulate (LT), causes a non-proportional increase in VO2 (Zoladz et al. 1995) which indicates a drop in muscle mechanical efficiency. The power output at which VO2 starts to rise non-proportionally to the power output has been called "the change point in VO2" (Zoladz et al. 1998). In this paper, the significance of the factors most likely involved in the physiological mechanism responsible for the change point in oxygen uptake (CP-VO2) and for the slow component of VO2 kinetics, including: increase of activation of additional muscle groups, intensification of the respiratory muscle activity, recruitment of type II muscle fibres, increase of muscle temperature, increase of the basal metabolic rate, lactate and hydrogen ion accumulation, proton leak through the inner mitochondrial membrane, slipping of the ATP synthase and a decrease in the cytosolic phosphorylation potential, are discussed. Finally, an original own model describing the sequence of events leading to the non-proportional increase of oxygen cost of work at a high exercise intensity is presented.

  17. Oxygen uptake during Wingate tests for arms and legs in swimmers and water polo players

    Directory of Open Access Journals (Sweden)

    Colantonio Emilson

    2003-01-01

    Full Text Available OBJECTIVE: The aim of the present study is to compare the values of the maximal oxygen uptake (O2 max during two consecutive bouts in Wingate tests for arms and legs in swimmers (S and water polo players (WP. METHODS: Sample - seven national level athletes (4 S and 3 WP, age 17,90 ± 2,14 years, body mass 71,41 ± 6,84 kg, height 176,65 ± 7,02 cm, % body fat 13,23 ± 4,18. Two Wingate bouts with 30 sec each with 3 min interval between them, for arms and legs in alternated days. Oxygen uptake: breath-by-breath using the gas analysis system K4 b² Cosmed. Statistical analysis: Wilcoxon test for dependent variables and Kolmogorov-Smirnov test for independent variables. RESULTS: The mean values found at the O2 peak (PO2, mean power (MP and peak power (PP for each bout of the Wingate test, for arms and legs. For Arms: PO2 = 55.16 ± 5.72 ml.kg-1.min-1, MP = 5.28 ± 0.59 watts.kg-1 and PP = 6.71 ± 0.88 watts.kg-1 got in the first bout (1st Arms and PO2 = 60.12 ± 6.10 ml.kg-1.min-1, MP = 5.03 ± 0.40 watts.kg-1 and PP = 6.25 ± 0.51 watts.kg-1, got in the second bout (2nd Arms. For legs: PO2 = 55.66 ± 6.85 ml.kg-1.min-1, MP = 4.75 ± 1.79 watts.kg-1 and PP = 7.44 ± 1.96 watts.kg-1 got in the first bout (1st Legs and PO2 = 62.09 ± 5.99 ml.kg-1.min-1, MP = 4.28 ± 1.47 watts.kg-1 and PP = 6.68 ± 1.63 watts.kg-1 got in the second bout (2nd Legs. DISCUSSION AND CONCLUSION: All variables studied did not present significant difference among arms and legs, as much the first as the second bout for arms for PO2 (p < 0.05. There was no difference between the PM mean values of the first and the second bout. But the mean of the second bout of legs was significant smaller than the first bout (p < 0.05. For the PP variable there was no difference among the mean values to the first and second bout as much for arms as for legs. It looks like to exist larger magnitude to O2 adjustment for arms than legs, that could be associated to specific demands to which S

  18. Opposite effects of WR-2721 and WR-1065 on radiation-induced hypothermia: possible correlation with oxygen uptake

    International Nuclear Information System (INIS)

    Kandasamy, S.B.; Kumar, K.S.; Hunt, W.A.; Weiss, J.F.

    1988-01-01

    Ionizing radiation induces hypothermia in guinea pigs. While systemic injection of the radioprotectant S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-2721) did not block hyperthermia induced by exposure to 10 Gy of gamma radiation, central administration did attenuate it. The dephosphorylated metabolite of WR-2721, N-(2-mercaptoethyl)-1,3-diaminopropane (WR-1065), accentuated radiation-induced hypothermia by both routes of administration. In brain homogenates, oxygen uptake was inhibited by WR-2721 but elevated by WR-1065. These results suggest that the antagonism of radiation-induced hypothermia found only after central administration of WR-2721 is due to its direct actions and not to its dephosphorylated metabolite and that this effect may be correlated with the inhibition by WR-2721 of oxygen uptake

  19. Uptake of vaporized molybdenum and cesium tracers by molten oxide mixtures as function of free oxygen ion activity

    International Nuclear Information System (INIS)

    Carmon, B.

    1975-11-01

    Molten mixtures of oxides containing Ca, Fe, Al, Na and Si were exposed to vaporized Mo-99 and Cs-137 tracers at 1100 and 1300 deg C. Uptake values at 1300 deg C were extrapolated to short heating times. The obtained ''attachment coefficients'' for that temperature are shown to have the relationship (Mo) approximately equal to (Cs)sup(-1/2). The chemical composition of the melts and their oxygen to metal ratio found to affect the uptake of both tracers. This is associated with the cationic field strengths and the free oxygen ion activities in the mixtures. Molybdenum and cesium apparently behave like glass-network forming and glass-network modifying species, respectively. (author)

  20. EFFECTS OF IMMOBILIZATION IN Ba-ALGINATE ON NITRILE-DEPENDENT OXYGEN UPTAKE RATES OF CANDIDA GUILLIERMONDII

    Directory of Open Access Journals (Sweden)

    Dias João Carlos Teixeira

    2001-01-01

    Full Text Available Yeast cells immobilized by entrapment in Ba-alginate gel were investigated for growth pattern and respiratory activity. The oxygen uptake rates (OUR of cells entrapped in gels with 4% alginate were 5.2 and 23% lower than the OUR of 2% alginate and free cells, respectively. The mass-transfer resistance offered by the matrix and growth of the entrapped cells determine a gradient of nutrients throughout the gel which is responsible for both a lower specific growth rate of immobilized cells with respect to that of free ones, and a heterogeneous biomass distribution, with progressively increasing cellular density from the inside to the outside of the matrix. Gel-matrix polymer concentration affected the maximum oxygen uptake of immobilized growing yeast cells.

  1. Peak Exercise Oxygen Uptake Predicts Recurrent Admissions in Heart Failure With Preserved Ejection Fraction.

    Science.gov (United States)

    Palau, Patricia; Domínguez, Eloy; Núñez, Eduardo; Ramón, José María; López, Laura; Melero, Joana; Sanchis, Juan; Bellver, Alejandro; Santas, Enrique; Bayes-Genis, Antoni; Chorro, Francisco J; Núñez, Julio

    2018-04-01

    Heart failure with preserved ejection fraction (HFpEF) is a highly prevalent syndrome with an elevated risk of morbidity and mortality. To date, there is scarce evidence on the role of peak exercise oxygen uptake (peak VO 2 ) for predicting the morbidity burden in HFpEF. We sought to evaluate the association between peak VO 2 and the risk of recurrent hospitalizations in patients with HFpEF. A total of 74 stable symptomatic patients with HFpEF underwent a cardiopulmonary exercise test between June 2012 and May 2016. A negative binomial regression method was used to determine the association between the percentage of predicted peak VO 2 (pp-peak VO 2 ) and recurrent hospitalizations. Risk estimates are reported as incidence rate ratios. The mean age was 72.5 ± 9.1 years, 53% were women, and all patients were in New York Heart Association functional class II to III. Mean peak VO 2 and median pp-peak VO 2 were 10 ± 2.8mL/min/kg and 60% (range, 47-67), respectively. During a median follow-up of 276 days [interquartile range, 153-1231], 84 all-cause hospitalizations in 31 patients (41.9%) were registered. A total of 15 (20.3%) deaths were also recorded. On multivariate analysis, accounting for mortality as a terminal event, pp-peak VO 2 was independently and linearly associated with the risk of recurrent admission. Thus, and modeled as continuous, a 10% decrease of pp-peak VO 2 increased the risk of recurrent hospitalizations by 32% (IRR, 1.32; 95%CI, 1.03-1.68; P = .028). In symptomatic elderly patients with HFpEF, pp-peak VO 2 predicts all-cause recurrent admission. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  2. 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.

  3. OXYGEN UPTAKE KINETICS DURING INCREMENTAL- AND DECREMENTAL-RAMP CYCLE ERGOMETRY

    Directory of Open Access Journals (Sweden)

    Fadıl Özyener

    2011-09-01

    Full Text Available The pulmonary oxygen uptake (VO2 response to incremental-ramp cycle ergometry typically demonstrates lagged-linear first-order kinetics with a slope of ~10-11 ml·min-1·W-1, both above and below the lactate threshold (ӨL, i.e. there is no discernible VO2 slow component (or "excess" VO2 above ӨL. We were interested in determining whether a reverse ramp profile would yield the same response dynamics. Ten healthy males performed a maximum incremental -ramp (15-30 W·min-1, depending on fitness. On another day, the work rate (WR was increased abruptly to the incremental maximum and then decremented at the same rate of 15-30 W.min-1 (step-decremental ramp. Five subjects also performed a sub-maximal ramp-decremental test from 90% of ӨL. VO2 was determined breath-by-breath from continuous monitoring of respired volumes (turbine and gas concentrations (mass spectrometer. The incremental-ramp VO2-WR slope was 10.3 ± 0.7 ml·min-1·W-1, whereas that of the descending limb of the decremental ramp was 14.2 ± 1.1 ml·min-1·W-1 (p < 0.005. The sub-maximal decremental-ramp slope, however, was only 9. 8 ± 0.9 ml·min-1·W-1: not significantly different from that of the incremental-ramp. This suggests that the VO2 response in the supra-ӨL domain of incremental-ramp exercise manifest not actual, but pseudo, first-order kinetics

  4. Effect of wearing clothes on oxygen uptake and ratings of perceived exertion while swimming.

    Science.gov (United States)

    Choi, S W; Kurokawa, T; Ebisu, Y; Kikkawa, K; Shiokawa, M; Yamasaki, M

    2000-07-01

    For a comparative study between swimming in swimwear (control-sw) and swimming in clothes (clothes-sw), oxygen uptake (VO2) and ratings of perceived exertion (RPE) were measured. The subjects were six male members of a university swimming team. Three swimming strokes--the breaststroke, the front crawl stroke and the elementary backstroke--were applied. With regards to clothes-sw, swimmers wore T-shirts, sportswear (shirt and pants) over swimwear and running shoes. In both cases of control-sw and clothes-sw, the VO2 was increased exponentially with increased swimming speed. The VO2 of the subjects during the clothed tests did not exceed 1.4 times of that in the case of control-sw at swimming speeds below 0.3 m/s. As swimming speeds increased, VO2 difference in both cases increased. Consequently, VO2 in the clothed tests was equal to 1.5-1.6 times and 1.5-1.8 times of that in the swimwear tests at speeds of 0.5 and 0.7 m/s, respectively. At speeds below 0.6 m/s in clothes-sw, the breaststroke showed lower VO2 than the front crawl stroke, and the elementary backstroke showed higher VO2 than the other two swimming strokes. RPE increased linearly with %peak VO2. In addition, any RPE differences among the three swimming strokes were not shown in the control-sw tests. At an exercise intensity above 60 %peak VO2, clothed swimmers showed slightly higher RPE in the front crawl stroke compared to that in the two other swimming strokes.

  5. Root porosity and radial oxygen loss related to arsenic tolerance and uptake in wetland plants

    Energy Technology Data Exchange (ETDEWEB)

    Li, H. [State Key Laboratory for Bio-control, and School of Life Sciences, Sun Yat-sen University, Guangzhou 510006 (China); Croucher Institute for Environmental Sciences, and Department of Biology, Hong Kong Baptist University, Kowloon Tong (Hong Kong); Ye, Z.H., E-mail: lssyzhh@mail.sysu.edu.c [State Key Laboratory for Bio-control, and School of Life Sciences, Sun Yat-sen University, Guangzhou 510006 (China); Wei, Z.J. [School of Information and Technology, Guangdong University of Foreign Studies, Guangzhou 510275 (China); Wong, M.H., E-mail: mhwong@hkbu.edu.h [Croucher Institute for Environmental Sciences, and Department of Biology, Hong Kong Baptist University, Kowloon Tong (Hong Kong)

    2011-01-15

    The rates of radial oxygen loss (ROL), root porosity, concentrations of arsenic (As), iron (Fe) and manganese (Mn) in shoot and root tissues and on root surfaces, As tolerances, and their relationships in different wetland plants were investigated based on a hydroponic experiment (control, 0.8, 1.6 mg As L{sup -1}) and a soil pot trail (control, 60 mg As kg{sup -1}). The results revealed that wetland plants showed great differences in root porosity (9-64%), rates of ROL (55-1750 mmo1 O{sub 2} kg{sup -1} root d.w. d{sup -1}), As uptake (e.g., 8.8-151 mg kg{sup -1} in shoots in 0.8 mg As L{sup -1} treatment), translocation factor (2.1-47% in 0.8 mg As L{sup -1}) and tolerance (29-106% in 0.8 mg As L{sup -1}). Wetland plants with higher rates of ROL and root porosity tended to form more Fe/Mn plaque, possess higher As tolerance, higher concentrations of As on root surfaces and a lower As translocation factor so decreasing As toxicity. - Research highlights: There is significant correlation between the porosity of roots and rates of ROL. The rates of ROL are significantly correlated with tolerance indices and concentrations of As, Fe, Mn on root surface. The rates of ROL is negatively correlated with As translocation factor. - Wetland plants with high rates of ROL tended to form more Fe plaque on root surfaces and possess higher As tolerance.

  6. Heart Rate and Oxygen Uptake Kinetics in Type 2 Diabetes Patients - A Pilot Study on the Influence of Cardiovascular Medication on Regulatory Processes.

    Science.gov (United States)

    Koschate, Jessica; Drescher, Uwe; Baum, Klaus; Brinkmann, Christian; Schiffer, Thorsten; Latsch, Joachim; Brixius, Klara; Hoffmann, Uwe

    2017-05-01

    The aim of this pilot study was to investigate whether there are differences in heart rate and oxygen uptake kinetics in type 2 diabetes patients, considering their cardiovascular medication. It was hypothesized that cardiovascular medication would affect heart rate and oxygen uptake kinetics and that this could be detected using a standardized exercise test. 18 subjects were tested for maximal oxygen uptake. Kinetics were measured in a single test session with standardized, randomized moderate-intensity work rate changes. Time series analysis was used to estimate kinetics. Greater maxima in cross-correlation functions indicate faster kinetics. 6 patients did not take any cardiovascular medication, 6 subjects took peripherally acting medication and 6 patients were treated with centrally acting medication. Maximum oxygen uptake was not significantly different between groups. Significant main effects were identified regarding differences in muscular oxygen uptake kinetics and heart rate kinetics. Muscular oxygen uptake kinetics were significantly faster than heart rate kinetics in the group with no cardiovascular medication (maximum in cross-correlation function of muscular oxygen uptake vs. heart rate; 0.32±0.08 vs. 0.25±0.06; p=0.001) and in the group taking peripherally acting medication (0.34±0.05 vs. 0.28±0.05; p=0.009) but not in the patients taking centrally acting medication (0.28±0.05 vs. 0.30±0.07; n.s.). It can be concluded that regulatory processes for the achievement of a similar maximal oxygen uptake are different between the groups. The used standardized test provided plausible results for heart rate and oxygen uptake kinetics in a single measurement session in this patient group. © Georg Thieme Verlag KG Stuttgart · New York.

  7. Evaluation of Optimum Moisture Content for Composting of Beef Manure and Bedding Material Mixtures Using Oxygen Uptake Measurement

    Directory of Open Access Journals (Sweden)

    Eunjong Kim

    2016-05-01

    Full Text Available Moisture content influences physiological characteristics of microbes and physical structure of solid matrices during composting of animal manure. If moisture content is maintained at a proper level, aerobic microorganisms show more active oxygen consumption during composting due to increased microbial activity. In this study, optimum moisture levels for composting of two bedding materials (sawdust, rice hull and two different mixtures of bedding and beef manure (BS, Beef cattle manure+sawdust; BR, Beef cattle manure+rice hull were determined based on oxygen uptake rate measured by a pressure sensor method. A broad range of oxygen uptake rates (0.3 to 33.3 mg O2/g VS d were monitored as a function of moisture level and composting feedstock type. The maximum oxygen consumption of each material was observed near the saturated condition, which ranged from 75% to 98% of water holding capacity. The optimum moisture content of BS and BR were 70% and 57% on a wet basis, respectively. Although BS’s optimum moisture content was near saturated state, its free air space kept a favorable level (above 30% for aerobic composting due to the sawdust’s coarse particle size and bulking effect.

  8. Evaluation of Optimum Moisture Content for Composting of Beef Manure and Bedding Material Mixtures Using Oxygen Uptake Measurement.

    Science.gov (United States)

    Kim, Eunjong; Lee, Dong-Hyun; Won, Seunggun; Ahn, Heekwon

    2016-05-01

    Moisture content influences physiological characteristics of microbes and physical structure of solid matrices during composting of animal manure. If moisture content is maintained at a proper level, aerobic microorganisms show more active oxygen consumption during composting due to increased microbial activity. In this study, optimum moisture levels for composting of two bedding materials (sawdust, rice hull) and two different mixtures of bedding and beef manure (BS, Beef cattle manure+sawdust; BR, Beef cattle manure+rice hull) were determined based on oxygen uptake rate measured by a pressure sensor method. A broad range of oxygen uptake rates (0.3 to 33.3 mg O2/g VS d) were monitored as a function of moisture level and composting feedstock type. The maximum oxygen consumption of each material was observed near the saturated condition, which ranged from 75% to 98% of water holding capacity. The optimum moisture content of BS and BR were 70% and 57% on a wet basis, respectively. Although BS's optimum moisture content was near saturated state, its free air space kept a favorable level (above 30%) for aerobic composting due to the sawdust's coarse particle size and bulking effect.

  9. Characterization of positron emission tomography hypoxia tracer uptake and tissue oxygenation via electrochemical modeling

    NARCIS (Netherlands)

    Bowen, S.R.; Kogel, A.J. van der; Nordsmark, M.; Bentzen, S.M.; Jeraj, R.

    2011-01-01

    PURPOSE: Unique uptake and retention mechanisms of positron emission tomography (PET) hypoxia tracers make in vivo comparison between them challenging. Differences in imaged uptake of two common hypoxia radiotracers, [(61)Cu]Cu-ATSM and [(18)F]FMISO, were characterized via computational modeling to

  10. Real-time monitoring of specific oxygen uptake rates of embryonic stem cells in a microfluidic cell culture device.

    Science.gov (United States)

    Super, Alexandre; Jaccard, Nicolas; Cardoso Marques, Marco Paulo; Macown, Rhys Jarred; Griffin, Lewis Donald; Veraitch, Farlan Singh; Szita, Nicolas

    2016-09-01

    Oxygen plays a key role in stem cell biology as a signaling molecule and as an indicator of cell energy metabolism. Quantification of cellular oxygen kinetics, i.e. the determination of specific oxygen uptake rates (sOURs), is routinely used to understand metabolic shifts. However current methods to determine sOUR in adherent cell cultures rely on cell sampling, which impacts on cellular phenotype. We present real-time monitoring of cell growth from phase contrast microscopy images, and of respiration using optical sensors for dissolved oxygen. Time-course data for bulk and peri-cellular oxygen concentrations obtained for Chinese hamster ovary (CHO) and mouse embryonic stem cell (mESCs) cultures successfully demonstrated this non-invasive and label-free approach. Additionally, we confirmed non-invasive detection of cellular responses to rapidly changing culture conditions by exposing the cells to mitochondrial inhibiting and uncoupling agents. For the CHO and mESCs, sOUR values between 8 and 60 amol cell(-1) s(-1) , and 5 and 35 amol cell(-1) s(-1) were obtained, respectively. These values compare favorably with literature data. The capability to monitor oxygen tensions, cell growth, and sOUR, of adherent stem cell cultures, non-invasively and in real time, will be of significant benefit for future studies in stem cell biology and stem cell-based therapies. © 2016 The Authors. Biotechnology Journal published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. 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

  12. Influence of oxygen uptake kinetics on physical performance in youth soccer.

    Science.gov (United States)

    Doncaster, Greg; Marwood, Simon; Iga, John; Unnithan, Viswanath

    2016-09-01

    To examine the relationship between oxygen uptake kinetics (VO2 kinetics) and physical measures associated with soccer match play, within a group of highly trained youth soccer players. Seventeen highly trained youth soccer players (age: 13.3 ± 0.4 year, self-assessed Tanner stage: 3 ± 1) volunteered for the study. Players initially completed an incremental treadmill protocol to exhaustion, to establish gaseous exchange threshold (GET) and VO2max (59.1 ± 5.4 mL kg(-1) min(-1)). On subsequent visits, players completed a step transition protocol from rest-moderate-intensity exercise, followed by an immediate transition, and from moderate- to severe-intensity exercise (moderate: 95 % GET, severe: 60 %∆), during which VO2 kinetics were determined. Physical soccer-based performance was assessed using a maximal Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1) and via GPS-derived measures of physical soccer performance during soccer match play, three 2 × 20 min, 11 v 11 matches, to gain measures of physical performance during soccer match play. Partial correlations revealed significant inverse relationships between the unloaded-to-moderate transition time constant (tau) and: Yo-Yo IR1 performance (r = -0.58, P = 0.02) and GPS variables [total distance (TD): r = -0.64, P = 0.007, high-speed running (HSR): r = -0.64, P = 0.008 and high-speed running efforts (HSReff): r = -0.66, P = 0.005]. Measures of VO2 kinetics are related to physical measures associated with soccer match play and could potentially be used to distinguish between those of superior physical performance, within a group of highly trained youth soccer players.

  13. Training-induced acceleration of oxygen uptake kinetics in skeletal muscle: the underlying mechanisms.

    Science.gov (United States)

    Zoladz, J A; Korzeniewski, B; Grassi, B

    2006-11-01

    It is well known that the oxygen uptake kinetics during rest-to-work transition (V(O2) on-kinetics) in trained subjects is significantly faster than in untrained individuals. It was recently postulated that the main system variable that determines the transition time (t(1/2)) of the V(O2) on-kinetics in skeletal muscle, at a given moderate ATP usage/work intensity, and under the assumption that creatine kinase reaction works near thermodynamic equilibrium, is the absolute (in mM) decrease in [PCr] during rest-to-work transition. Therefore we postulate that the training-induced acceleration of the V(O2) on-kinetics is a marker of an improvement of absolute metabolic stability in skeletal muscles. The most frequently postulated factor responsible for enhancement of muscle metabolic stability is the training-induced increase in mitochondrial proteins. However, the mechanism proposed by Gollnick and Saltin (1982) can improve absolute metabolic stability only if training leads to a decrease in resting [ADP(free)]. This effect is not observed in many examples of training causing an acceleration of the V(O2) on-kinetics, especially in early stages of training. Additionally, this mechanism cannot account for the significant training-induced increase in the relative (expressed in % or as multiples of the resting values) metabolic stability at low work intensities, condition in which oxidative phosphorylation is not saturated with [ADP(free)]. Finally, it was reported that in the early stage of training, acceleration in the V(O2) on-kinetics and enhancement of muscle metabolic stability may precede adaptive responses in mitochondrial enzymes activities or mitochondria content. We postulate that the training-induced acceleration in the V(O2) on-kinetics and the improvement of the metabolite stability during moderate intensity exercise in the early stage of training is mostly caused by an intensification of the "parallel activation" of ATP consumption and ATP supply pathways

  14. Oxygen Uptake Kinetics Is Slower in Swimming Than Arm Cranking and Cycling during Heavy Intensity

    Science.gov (United States)

    Sousa, Ana; Borrani, Fabio; Rodríguez, Ferran A.; Millet, Grégoire P.

    2017-01-01

    Oxygen uptake (V·O2) kinetics has been reported to be influenced by the activity mode. However, only few studies have compared V·O2 kinetics between activities in the same subjects in which they were equally trained. Therefore, this study compared the V·O2 kinetics response to swimming, arm cranking, and cycling within the same group of subjects within the heavy exercise intensity domain. Ten trained male triathletes (age 23.2 ± 4.5 years; height 180.8 ± 8.3 cm; weight 72.3 ± 6.6 kg) completed an incremental test to exhaustion and a 6-min heavy constant-load test in the three exercise modes in random order. Gas exchange was measured by a breath-by-breath analyzer and the on-transient V·O2 kinetics was modeled using bi-exponential functions. V·O2peak was higher in cycling (65.6 ± 4.0 ml·kg−1·min−1) than in arm cranking or swimming (48.7 ± 8.0 and 53.0 ± 6.7 ml·kg−1·min−1; P kinetics were slower in swimming (τ1 = 31.7 ± 6.2 s) than in arm cranking (19.3 ± 4.2 s; P = 0.001) and cycling (12.4 ± 3.7 s; P = 0.001). The amplitude of the primary component was lower in both arm cranking and swimming (21.9 ± 4.7 and 28.4 ± 5.1 ml·kg−1·min−1) compared with cycling (39.4 ± 4.1 ml·kg−1·min−1; P = 0.001). Although the gain of the primary component was higher in arm cranking compared with cycling (15.3 ± 4.2 and 10.7 ± 1.3 ml·min−1·W−1; P = 0.02), the slow component amplitude, in both absolute and relative terms, did not differ between exercise modes. The slower V·O2 kinetics during heavy-intensity swimming is exercise-mode dependent. Besides differences in muscle mass and greater type II muscle fibers recruitment, the horizontal position adopted and the involvement of trunk and lower-body stabilizing muscles could be additional mechanisms that explain the differences between exercise modalities. PMID:28919863

  15. The role of oxygen in the uptake of deuterium in lithiated graphite

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, C. N.; Luitjohan, K. E. [School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Dadras, J. [Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37998 (United States); Allain, J. P. [School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Birck Nanotechnology Center, West Lafayette, Indiana 47907 (United States); Krstic, P. S. [Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37998 (United States); Joint Institute of Computational Sciences, University of Tennessee, Knoxville, Tennessee 37998 (United States); Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Skinner, C. H. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2013-12-14

    We investigate the mechanism of deuterium retention by lithiated graphite and its relationship to the oxygen concentration through surface sensitive experiments and atomistic simulations. Deposition of lithium on graphite yielded 5%–8% oxygen surface concentration and when subsequently irradiated with D ions at energies between 500 and 1000 eV/amu and fluences over 10{sup 16} cm{sup −2} the oxygen concentration rose to between 25% and 40%. These enhanced oxygen levels were reached in a few seconds compared to about 300 h when the lithiated graphite was allowed to adsorb oxygen from the ambient environment under equilibrium conditions. Irradiating graphite without lithium deposition, however, resulted in complete removal of oxygen to levels below the detection limit of XPS (e.g., <1%). These findings confirm the predictions of atomistic simulations, which had concluded that oxygen was the primary component for the enhanced hydrogen retention chemistry on the lithiated graphite surface.

  16. Leg oxygen uptake in the initial phase of intense exercise is slowed by a marked reduction in oxygen delivery

    DEFF Research Database (Denmark)

    Christensen, Peter Møller; Nyberg, Michael Permin; Mortensen, Stefan Peter

    2013-01-01

    -extensor exercise (60±3 W) for 4 min in a control setting (CON) and with arterial infusion of L-NMMA and indomethacin in the working leg to reduce blood flow by inhibiting formation of nitric oxide and prostanoids (double blockade; DB). In DB leg blood flow (LBF) and oxygen delivery during the first minute...

  17. Gill structural change in response to turbidity has no effect on the oxygen uptake of a juvenile sparid fish.

    Science.gov (United States)

    Cumming, H; Herbert, N A

    2016-01-01

    Turbidity as a result of increased suspended sediments in coastal waters is an environmental stress of worldwide concern. Recent research on fish suggests that detrimental changes to gill structure can occur in turbid waters, with speculation that these alterations diminish fitness variables, such as growth and development, by negatively impacting the O 2 uptake capacity (respiration) of fish. Specifically to address this unknown, the impact of turbid water on the gill structure, somatic growth rate and O 2 uptake rates of a juvenile sparid species ( Pagrus auratus ) was addressed following exposure to five different turbidity treatments (turbidity units) for 30 days. Significant gill structural change was apparent with a progressive increase in turbidity and was quantified as a reduction in lamellar density, as well as an increase in basal hyperplasia, epithelial lifting and increased oxygen diffusion distance across the lamellae. The weight of control fish did not change throughout the experiment, but all fish exposed to turbid waters lost weight, and weight loss increased with nephelometric turbidity units, confirming that long-term turbidity exposure is detrimental to growth productivity. The growth of fish could be impacted in a variety of ways, but the specific hypothesis that structural alteration of the gills impairs O 2 uptake across the gills and limits growth fitness was not supported because there was no measurable difference in the standard metabolic rate, maximal metabolic rate, aerobic metabolic scope or critical oxygen saturation limit of fish measured in clear water after 30 days of exposure. Although impaired O 2 uptake as a result of structurally adjusted gills is unlikely to be the cause of poor fish growth, the exact mechanism by which growth productivity is affected in turbid conditions remains unclear and warrants further investigation.

  18. Usefulness of decrease in oxygen uptake efficiency to identify gas exchange abnormality in patients with idiopathic pulmonary arterial hypertension.

    Directory of Open Access Journals (Sweden)

    Xiaoyue Tan

    Full Text Available BACKGROUND: Decline in oxygen uptake efficiency (OUE, especially during exercise, is found in patients with chronic heart failure. In this study we aimed to test the validity and usefulness of OUE in evaluating gas exchange abnormality of patients with idiopathic pulmonary arterial hypertension (IPAH. METHODS: We retrospectively investigated the cardiopulmonary exercise test (CPET with gas exchange measurements in 32 patients with confirmed IPAH. All patients also had resting hemodynamic measurements and pulmonary function test (PFT. Sixteen healthy subjects, matched by age, sex, and body size were used as controls, also had CPET and PFT measurements. RESULTS: In IPAH patients, the magnitude of absolute and percentage of predicted (%pred oxygen uptake efficiency slope (OUES and oxygen uptake efficiency plateau (OUEP, as well as several other CPET parameters, were strikingly worse than healthy subjects (P<0.0001. Pattern of changes in OUE in patients is similar to that in controls, In IPAH patients, OUE values at rest, warming up, anaerobic threshold and peak exercise were all significantly lower than in normal (P<0.0001. OUEP%pred, better than OUES%pred, correlated significantly with New York Heart Association (NYHA functional Class (r = -0.724, P<0.005, Total Pulmonary Vascular Resistance (TPVR (r = -0.694, P<0.005, diffusing capacity for carbon monoxide (DLCO (r = 0.577, P<0.05, and the lowest ventilation versus CO2 output ratio during exercise (LowestV˙E/V˙CO2 (r = -0.902, P<0.0001. In addition, the coefficient of variation (COV of OUEP was lower (20.9% markedly than OUES (34.3% (P<0.0001. CONCLUSIONS: In patients with IPAH, OUES and OUEP are both significantly lower than the healthy subjects. OUEP is a better physiological parameter than OUES in evaluating the gas exchange abnormality of patients with IPAH.

  19. The effects of radial oxygen loss on arsenic tolerance and uptake in rice and on its rhizosphere

    International Nuclear Information System (INIS)

    Mei, X.Q.; Wong, M.H.; Yang, Y.; Dong, H.Y.; Qiu, R.L.; Ye, Z.H.

    2012-01-01

    Understanding the complex biotic and abiotic interactions invoked by the rice root system in oxygen-depleted soil is an important step in screening genotypes for low toxic metal or metalloid accumulation. A hydroponic and a rhizobox experiment have been conducted to explore the effects of varying root oxygen release on chemical changes, As fractionation in rhizosphere soil and Fe plaque formation, As uptake and tolerance by different rice genotypes. The results showed that rice genotypes with higher rates of radial oxygen loss (ROL) and at the bolting stage, tended to have greater effects on rhizosphere Eh, pH, Fe 3+ /Fe 2+ quotients, As fractionation and mobility and also on Fe plaque formation compared to those with lower ROL and at the tillering stage. Genotypes with higher ROL have a strong ability to reduce As accumulation in shoots and increase As tolerance by reducing As mobilization in the rhizosphere and by limiting As translocation. - Highlights: ► We investigate the effects of ROL on As tolerance, uptake, and changes in rhizosphere of rice genotypes and their correlation. ► Indices of As tolerance of genotypes are positively correlated with their rates of ROL. ► Genotypes with higher rates of ROL have greater effects on rhizosphere. ► Genotypes with higher rates of ROL have a strong ability to reduce As uptake by immobilizing As on roots and in rhizosphere. - Rice genotypes with high ROL and at the bolting stage have greater effects on their rhizosphere than others with lower ROL and at tillering stage and also have lower shoot As and higher As tolerance.

  20. Age-related changes in oxygen and nutrient uptake by hindquarters in newborn pigs during cold-induced shivering.

    Science.gov (United States)

    Lossec, G; Lebreton, Y; Hulin, J C; Fillaut, M; Herpin, P

    1998-11-01

    Newborn pigs rely essentially on shivering thermogenesis in the cold. In order to understand the rapid postnatal enhancement of thermogenic capacities in piglets, the oxygen and nutrient uptake of hindquarters was measured in vivo in 1- (n = 6) and 5-day-old (n = 6) animals at thermal neutrality and during cold exposure. The hindquarters were considered to represent a skeletal muscle compartment. Indirect calorimetry and arterio-venous techniques were used. The cold challenge (23 C at 1 day old and 15 C at 5 days old for 90 min) induced a similar increase (+90 %) in regulatory heat production at both ages. Hindquarters blood flow was higher at 5 days than 1 day old at thermal neutrality (26 +/- 3 vs. 17 +/- 1 ml min-1 (100 g hindquarters)-1) and its increase in the cold was much more marked (+65 % at 5 days old vs. +25 % at 1 day old). Oxygen extraction by the hindquarters rose from 30-35 % at thermal neutrality to 65-70 % in the cold at both ages. The calculated contribution of skeletal muscle to total oxygen consumption averaged 34-40 % at thermal neutrality and 50-64 % in the cold and skeletal muscle was the major contributor to regulatory thermogenesis. Based on hindquarters glucose uptake and lactate release, carbohydrate appeared to be an important fuel for shivering. However, net uptake of fatty acids increased progressively during cold exposure at 5 days old. The enhancement in muscular blood supply and fatty acid utilization during shivering is probably related to the postnatal improvement in the thermoregulatory response of the piglet.

  1. 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...

  2. Calculation of hydrogen and oxygen uptake in fuel rod cladding during severe accidents using the integral diffusion method -- Preliminary design report

    International Nuclear Information System (INIS)

    Siefken, L.J.

    1999-01-01

    Preliminary designs are described for models of hydrogen and oxygen uptake in fuel rod cladding during severe accidents. Calculation of the uptake involves the modeling of seven processes: (1) diffusion of oxygen from the bulk gas into the boundary layer at the external cladding surface, (2) diffusion from the boundary layer into the oxide layer, (3) diffusion from the inner surface of the oxide layer into the metallic part of the cladding, (4) uptake of hydrogen in the event that the cladding oxide layer is dissolved in a steam-starved region, (5) embrittlement of cladding due to hydrogen uptake, (6) cracking of cladding during quenching due to its embrittlement and (7) release of hydrogen from the cladding after cracking of the cladding. An integral diffusion method is described for calculating the diffusion processes in the cladding. Experimental results are presented that show a rapid uptake of hydrogen in the event of dissolution of the oxide layer and a rapid release of hydrogen in the event of cracking of the oxide layer. These experimental results are used as a basis for calculating the rate of hydrogen uptake and the rate of hydrogen release. The uptake of hydrogen is limited to the equilibrium solubility calculated by applying Sievert's law. The uptake of hydrogen is an exothermic reaction that accelerates the heatup of a fuel rod. An embrittlement criteria is described that accounts for hydrogen and oxygen concentration and the extent of oxidation. A design is described for implementing the models for hydrogen and oxygen uptake and cladding embrittlement into the programming framework of the SCDAP/RELAP5 code. A test matrix is described for assessing the impact of the proposed models on the calculated behavior of fuel rods in severe accident conditions. This report is a revision and reissue of the report entitled; ''Preliminary Design Report for Modeling of Hydrogen Uptake in Fuel Rod Cladding During Severe Accidents.''

  3. Genetic variants of uncoupling proteins-2 and -3 in relation to maximal oxygen uptake in different sports.

    Science.gov (United States)

    Holdys, Joanna; Gronek, Piotr; Kryściak, Jakub; Stanisławski, Daniel

    2013-01-01

    Uncoupling proteins 2 and 3 (UCP2 and UCP3) as mitochondrial electron transporters are involved in regulation of ATP production and energy dissipation as heat. Energy efficiency plays an important role in physical performance, especially in aerobic fitness. The aim of this study was to examine the association between maximal oxygen uptake and genetic variants of the UCP2 and UCP3 genes. The studies were carried out in a group of 154 men and 85 women, professional athletes representing various sports and fitness levels and students of the University of Physical Education in Poznań. Physiological and molecular procedures were used, i.e. direct measurement of maximum oxygen uptake (VO₂max) and analysis of an insertion/deletion (I/D) polymorphism in the 3'untranslated region of exon 8 of the UCP2 gene and a C>T substitution in exon 5 (Y210Y) of the UCP3 gene. No statistically significant associations were found, only certain trends. Insertion allele (I) of the I/D UCP2 and the T allele of the UCP3 gene were favourable in obtaining higher VO₂max level and might be considered as endurance-related alleles.

  4. Endurance training decreases the non-linearity in the oxygen uptake-power output relationship in humans.

    Science.gov (United States)

    Majerczak, Joanna; Korostynski, Michal; Nieckarz, Zenon; Szkutnik, Zbigniew; Duda, Krzysztof; Zoladz, Jerzy A

    2012-03-01

    In this study, we hypothesized that 5 weeks of cycling endurance training can decrease the magnitude of the non-proportional increase in oxygen uptake (V(O(2))) to power output relationship (V(O(2)) 'excess') at exercise intensities exceeding the lactate threshold (LT). Ten untrained, physically active men performed a bout of incremental cycling exercise until exhaustion before and after training. The mitochondrial DNA copy number, myosin heavy chain composition and content of uncoupling protein 3 and sarcoplasmic reticulum Ca(2+)-ATPases (SERCAs) were analysed in muscle biopsies taken from vastus lateralis before and after training. The training resulted in an enhancement of the power-generating capabilities at maximal oxygen uptake (V(O(2)max)) by ∼7% (P = 0.002) despite there being no changes in V(O(2)max) (P = 0.49). This effect was due to a considerable reduction in the magnitude of the V(O(2)) 'excess' (P 0.05) were found after training. We conclude that the training-induced increase in power-generating capabilities at V(O(2)max) was due to attenuation of the V(O(2)) 'excess' above the LT. This adaptive response seems to be related to the improvement of muscle metabolic stability, as judged by a lowering of plasma ammonia concentration. The enhancement of muscle metabolic stability after training could be caused by a decrease in ATP usage at a given power output owing to downregulation of SERCA2 pumps.

  5. Oxygen uptake from aquatic macrophyte decomposition from Piraju Reservoir (Piraju, SP, Brazil

    Directory of Open Access Journals (Sweden)

    I. Bianchini Jr.

    Full Text Available The kinetics of oxygen consumption related to mineralisation of 18 taxa of aquatic macrophytes (Cyperus sp, Azolla caroliniana, Echinodorus macrophyllus, Eichhornia azurea, Eichhornia crassipes, Eleocharis sp1, Eleocharis sp2, Hetereanthera multiflora, Hydrocotyle raniculoides, Ludwigia sp, Myriophyllum aquaticum, Nymphaea elegans, Oxycaryum cubense, Ricciocarpus natans, Rynchospora corymbosa, Salvinia auriculata, Typha domingensis and Utricularia foliosa from the reservoir of Piraju Hydroelectric Power Plant (São Paulo state, Brazil were described. For each species, two incubations were prepared with ca. 300.0 mg of plant (DW and 1.0 L of reservoir water sample. The incubations were maintained in the dark and at 20 ºC. Periodically the dissolved oxygen (DO concentrations were measured; the accumulated DO values were fitted to 1st order kinetic model and the results showed that: i high oxygen consumption was observed for Ludwigia sp (533 mg g-1 DW, while the lowest was registered for Eleocharis sp1 (205 mg g-1 DW mineralisation; ii the higher deoxygenation rate constants were verified in the mineralisation of A. caroliniana (0.052 day-1, H. raniculoides (0.050 day-1 and U. foliosa (0.049 day-1. The oxygen consumption rate constants of Ludwigia sp and Eleocharis sp2 mineralisation (0.027 day-1 were the lowest. The half-time of oxygen consumption varied from 9 to 26 days. In the short term, the detritus of E. macrophyllus, H. raniculoides, Ludwigia sp, N. elegans and U. foliosa were the critical resources to the reservoir oxygen demand; while in the long term, A. caroliniana, H. multiflora and T. domingensis were the resources that can potentially contribute to the benthic oxygen demand of this reservoir.

  6. Microelectrode Studies of Seasonal Oxygen-Uptake in a Coastal Sediment - Role of Molecular-Diffusion

    DEFF Research Database (Denmark)

    RASMUSSEN, H.; JØRGENSEN, BB

    1992-01-01

    in the bay varied from 100 % air saturation during winter to 23 % during summer. The potentially higher O2 respiration during the summer months was counteracted by a lower O2 concentration in the bottom water, which led to a small seasonal variation in O2 uptake. Depth of the oxic sediment zone reached 5.1...... surface zone. The O2 consumption rates in the oxic surface layer, calculated from (b) and (c) using molecular diffusion coefficients of O2, closely agreed and accounted for 70 % of the total O2 uptake. The O2 uptake rates strongly depended on in situ O2 concentrations in the overlying seawater, which...... mm during winter, narrowed down rapidly to a few mm upon settling of a spring phytoplankton bloom, and was only 1.2 mm during summer. Modeling of O2 consumption from O2 microprofiles showed zero-order kinetics, i.e. constant O2 consumption rates throughout the oxic zone during winter. Enhanced O2...

  7. An in silico analysis of oxygen uptake of a mild COPD patient during rest and exercise using a portable oxygen concentrator

    Directory of Open Access Journals (Sweden)

    Katz I

    2016-09-01

    Full Text Available Ira Katz,1,2 Marine Pichelin,1 Spyridon Montesantos,1 Min-Yeong Kang,3 Bernard Sapoval,3,4 Kaixian Zhu,5 Charles-Philippe Thevenin,5 Robert McCoy,6 Andrew R Martin,7 Georges Caillibotte1 1Medical R&D, Air Liquide Santé International, Centre de Recherche Paris-Saclay, Les Loges-en-Josas, France; 2Department of Mechanical Engineering, Lafayette College, Easton, PA, USA; 3Physique de la Matière Condensée, CNRS, Ecole Polytechnique, Palaiseau, 4Centre de Mathématiques et de leurs Applications, CNRS, UniverSud, Cachan, 5Centre Explor!, Air Liquide Healthcare, Gentilly, France; 6Valley Inspired Products, Inc, Apple Valley, MN, USA; 7Department of Mechanical Engineering, University of Alberta, Edmonton, AB, Canada Abstract: Oxygen treatment based on intermittent-flow devices with pulse delivery modes available from portable oxygen concentrators (POCs depends on the characteristics of the delivered pulse such as volume, pulse width (the time of the pulse to be delivered, and pulse delay (the time for the pulse to be initiated from the start of inhalation as well as a patient’s breathing characteristics, disease state, and respiratory morphology. This article presents a physiological-based analysis of the performance, in terms of blood oxygenation, of a commercial POC at different settings using an in silico model of a COPD patient at rest and during exercise. The analysis encompasses experimental measurements of pulse volume, width, and time delay of the POC at three different settings and two breathing rates related to rest and exercise. These experimental data of device performance are inputs to a physiological-based model of oxygen uptake that takes into account the real dynamic nature of gas exchange to illustrate how device- and patient-specific factors can affect patient oxygenation. This type of physiological analysis that considers the true effectiveness of oxygen transfer to the blood, as opposed to delivery to the nose (or mouth, can be

  8. In vitro kinetic studies on the mechanism of oxygen-dependent cellular uptake of copper radiopharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    Holland, Jason P; Bell, Stephen G; Wong, Luet-Lok; Dilworth, Jonathan R [Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA (United Kingdom); Giansiracusa, Jeffrey H [Department of Mathematics, Mathematical Institute, University of Oxford, 24-29 St Giles' , Oxford, OX1 3LB (United Kingdom)], E-mail: hollanj3@mskcc.org, E-mail: jasonpholland@gmail.com

    2009-04-07

    The development of hypoxia-selective radiopharmaceuticals for use as therapeutic and/or imaging agents is of vital importance for both early identification and treatment of cancer and in the design of new drugs. Radiotracers based on copper for use in positron emission tomography have received great attention due to the successful application of copper(II) bis(thiosemicarbazonato) complexes, such as [{sup 60/62/64}Cu(II)ATSM] and [{sup 60/62/64}Cu(II)PTSM], as markers for tumour hypoxia and blood perfusion, respectively. Recent work has led to the proposal of a revised mechanism of hypoxia-selective cellular uptake and retention of [Cu(II)ATSM]. The work presented here describes non-steady-state kinetic simulations in which the reported pO{sub 2}-dependent in vitro cellular uptake and retention of [{sup 64}Cu(II)ATSM] in EMT6 murine carcinoma cells has been modelled by using the revised mechanistic scheme. Non-steady-state (NSS) kinetic analysis reveals that the model is in very good agreement with the reported experimental data with a root-mean-squared error of less than 6% between the simulated and experimental cellular uptake profiles. Estimated rate constants are derived for the cellular uptake and washout (k{sub 1} = 9.8 {+-} 0.59 x 10{sup -4} s{sup -1} and k{sub 2} = 2.9 {+-} 0.17 x 10{sup -3} s{sup -1}), intracellular reduction (k{sub 3} = 5.2 {+-} 0.31 x 10{sup -2} s{sup -1}), reoxidation (k{sub 4} = 2.2 {+-} 0.13 mol{sup -1} dm{sup 3} s{sup -1}) and proton-mediated ligand dissociation (k{sub 5} = 9.0 {+-} 0.54 x 10{sup -5} s{sup -1}). Previous mechanisms focused on the reduction and reoxidation steps. However, the data suggest that the origins of hypoxia-selective retention may reside with the stability of the copper(I) anion with respect to protonation and ligand dissociation. In vitro kinetic studies using the nicotimamide adenine dinucleotide (NADH)-dependent ferredoxin reductase enzyme PuR isolated from the bacterium Rhodopseudomonas palustris have

  9. Oxygen in the deep-sea: The challenge of maintaining uptake rates in a changing ocean

    Science.gov (United States)

    Hofmann, A. F.; Peltzer, E. T.; Brewer, P. G.

    2011-12-01

    Although focused on recently, ocean acidification is not the only effect of anthropogenic CO2 emissions on the ocean. Ocean warming will reduce dissolved oxygen concentrations and at the hypoxic limit for a given species this can pose challenges to marine life. The limit is traditionally reported simply as the static mass concentration property [O2]; here we treat it as a dynamic gas exchange problem for the animal analogous to gas exchange at the sea surface. The diffusive limit and its relationship to water velocity is critical for the earliest stages of marine life (eggs, embryos), but the effect is present for all animals at all stages of life. We calculate the external limiting O2 conditions for several representative metabolic rates and their relationship to flow of the bulk fluid under different environmental conditions. Ocean O2 concentrations decline by ≈ 14 μmol kg-1 for a 2 °C rise in temperature. At standard 1000 m depth conditions in the Pacific, flow over the surface would have to increase by ≈ 60% from 2.0 to 3.2 cm s-1 to compensate for this change. The functions derived allow new calculations of depth profiles of limiting O2 concentrations, as well as maximal diffusively sustainable metabolic oxygen consumption rates at various places around the world. Our treatment shows that there is a large variability in the global ocean in terms of facilitating aerobic life. This variability is greater than the variability of the oxygen concentration alone. It becomes clear that temperature and pressure dependencies of diffusion and partial pressure create a region typically around 1000 m depth where a maximal [O2] is needed to sustain a given metabolic rate. This zone of greatest physical constriction on the diffusive transport in the boundary layer is broadly consistent with the oxygen minimum zone, i.e., the zone of least oxygen concentration supply, resulting in a pronounced minimum of maximal diffusively sustainable metabolic oxygen consumption

  10. Hepatic encephalopathy is associated with decreased cerebral oxygen metabolism and blood flow, not increased ammonia uptake

    DEFF Research Database (Denmark)

    Dam, Gitte; Keiding, Susanne; Munk, Ole Lajord

    2013-01-01

    Studies have shown decreased cerebral oxygen metabolism (CMRO(2)) and blood flow (CBF) in patients with cirrhosis with hepatic encephalopathy (HE). It remains unclear, however, whether these disturbances are associated with HE or with cirrhosis itself and how they may relate to arterial blood...... associated with HE rather than the liver disease as such. The changes in CMRO(2) and CBF could not be linked to blood ammonia concentration or CMRA....

  11. Prior exercise speeds pulmonary oxygen uptake kinetics and increases critical power during supine but not upright cycling.

    Science.gov (United States)

    Goulding, Richie P; Roche, Denise M; Marwood, Simon

    2017-09-01

    What is the central question of this study? Critical power (CP) represents the highest work rate for which a metabolic steady state is attainable. The physiological determinants of CP are unclear, but research suggests that CP might be related to the time constant of phase II oxygen uptake kinetics (τV̇O2). What is the main finding and its importance? We provide the first evidence that τV̇O2 is mechanistically related to CP. A reduction of τV̇O2 in the supine position was observed alongside a concomitant increase in CP. This effect may be contingent on measures of oxygen availability derived from near-infrared spectroscopy. Critical power (CP) is a fundamental parameter defining high-intensity exercise tolerance and is related to the time constant of phase II pulmonary oxygen uptake kinetics (τV̇O2). To test the hypothesis that this relationship is causal, we determined the impact of prior exercise ('priming') on CP and τV̇O2 in the upright and supine positions. Seventeen healthy men were assigned to either upright or supine exercise groups, whereby CP, τV̇O2 and muscle deoxyhaemoglobin kinetics (τ [HHb] ) were determined via constant-power tests to exhaustion at four work rates with (primed) and without (control) priming exercise at ∼31%Δ. During supine exercise, priming reduced τV̇O2 (control 54 ± 18 s versus primed 39 ± 11 s; P exercise had no effect on τV̇O2 (control 37 ± 12 s versus primed 35 ± 8 s; P = 0.82), τ [HHb] (control 10 ± 5 s versus primed 14 ± 10 s; P = 0.10) or CP (control 235 ± 42 W versus primed 232 ± 35 W; P = 0.57) during upright exercise. The concomitant reduction of τV̇O2 and increased CP following priming in the supine group, effects that were absent in the upright group, provide the first experimental evidence that τV̇O2 is mechanistically related to critical power. The increased τ [HHb+Mb] suggests that this effect was mediated, at least in part, by improved oxygen

  12. The role of radial oxygen loss and root anatomy on zinc uptake and tolerance in mangrove seedlings

    International Nuclear Information System (INIS)

    Cheng, H.; Liu, Y.; Tam, N.F.Y.; Wang, X.; Li, S.Y.; Chen, G.Z.; Ye, Z.H.

    2010-01-01

    Root anatomy, radial oxygen loss (ROL) and zinc (Zn) uptake and tolerance in mangrove plants were investigated using seedlings of Aegiceras corniculatum, Bruguiera gymnorrhiza and Rhizophora stylosa. The results revealed that B. gymnorrhiza, which possessed the 'tightest barrier' in ROL spatial patterns among the three species studied, took up the least Zn and showed the highest Zn tolerance. Furthermore, zinc significantly decreased the ROL of all three plants by inhibition of root permeability, which included an obvious thickening of outer cortex and significant increases of lignification in cell walls. The results of SEM X-ray microanalysis further confirmed that such an inducible, low permeability of roots was likely an adaptive strategy to metal stress by direct prevention of excessive Zn entering into the root. The present study proposes new evidence of structural adaptive strategy on metal tolerance by mangrove seedlings. - Mangrove seedlings with a 'tighter barrier' in ROL spatial pattern exhibit higher Zn tolerance.

  13. The role of radial oxygen loss and root anatomy on zinc uptake and tolerance in mangrove seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, H. [State Key Laboratory for Bio-control, and School of Life Sciences, Sun Yat-sen University, Guangzhou 510006 (China); Liu, Y. [Ministry of Agriculture Key Laboratory of Mariculture Ecology and Products Quality and Safety, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300 (China); Tam, N.F.Y. [Department of Biology and Chemistry, City University of Hong Kong (Hong Kong); Wang, X. [State Key Laboratory for Bio-control, and School of Life Sciences, Sun Yat-sen University, Guangzhou 510006 (China); Li, S.Y.; Chen, G.Z. [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Ye, Z.H., E-mail: lssyzhh@mail.sysu.edu.c [State Key Laboratory for Bio-control, and School of Life Sciences, Sun Yat-sen University, Guangzhou 510006 (China)

    2010-05-15

    Root anatomy, radial oxygen loss (ROL) and zinc (Zn) uptake and tolerance in mangrove plants were investigated using seedlings of Aegiceras corniculatum, Bruguiera gymnorrhiza and Rhizophora stylosa. The results revealed that B. gymnorrhiza, which possessed the 'tightest barrier' in ROL spatial patterns among the three species studied, took up the least Zn and showed the highest Zn tolerance. Furthermore, zinc significantly decreased the ROL of all three plants by inhibition of root permeability, which included an obvious thickening of outer cortex and significant increases of lignification in cell walls. The results of SEM X-ray microanalysis further confirmed that such an inducible, low permeability of roots was likely an adaptive strategy to metal stress by direct prevention of excessive Zn entering into the root. The present study proposes new evidence of structural adaptive strategy on metal tolerance by mangrove seedlings. - Mangrove seedlings with a 'tighter barrier' in ROL spatial pattern exhibit higher Zn tolerance.

  14. Biomass characterization by dielectric monitoring of viability and oxygen uptake rate measurements in a novel membrane bioreactor.

    Science.gov (United States)

    Shariati, Farshid Pajoum; Heran, Marc; Sarrafzadeh, Mohammad Hossein; Mehrnia, Mohammad Reza; Sarzana, Gabriele; Ghommidh, Charles; Grasmick, Alain

    2013-07-01

    The application of permittivity and oxygen uptake rate (OUR) as biological process control parameters in a wastewater treatment system was evaluated. Experiments were carried out in a novel airlift oxidation ditch membrane bioreactor under different organic loading rates (OLR). Permittivity as representative of activated sludge viability was measured by a capacitive on-line sensor. OUR was also measured as a representative for respirometric activity. Results showed that the biomass concentration increases with OLR and all biomass related measurements and simulators such as MLSS, permittivity, OUR, ASM1 and ASM3 almost follow the same increasing trends. The viability of biomass decreased when the OLR was reduced from 5 to 4 kg COD m(-3)d(-1). During decreasing of OLR, biomass related parameters generally decreased but not in a similar manner. Also, protein concentration in the system during OLR decreasing changed inversely with the activated sludge viability. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. The relationship between skeletal muscle mitochondrial citrate synthase activity and whole body oxygen uptake adaptations in response to exercise training

    DEFF Research Database (Denmark)

    Vigelsø, Andreas; Andersen, Nynne B; Dela, Flemming

    2014-01-01

    Citrate synthase (CS) activity is a validated biomarker for mitochondrial density in skeletal muscle. CS activity is also used as a biochemical marker of the skeletal muscle oxidative adaptation to a training intervention, and a relationship between changes in whole body aerobic capacity and chan......Citrate synthase (CS) activity is a validated biomarker for mitochondrial density in skeletal muscle. CS activity is also used as a biochemical marker of the skeletal muscle oxidative adaptation to a training intervention, and a relationship between changes in whole body aerobic capacity...... and changes in CS activity is often assumed. However, this relationship and absolute values of CS and maximal oxygen uptake (V.O2max) has never been assessed across different studies. A systematic PubMed search on literature published from 1983 to 2013 was performed. The search profile included: citrate...... and CS activity. 70 publications with 97 intervention groups were included. There was a positive (r = 0.45) correlation (P

  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. Oxygen uptake by excised gills of Procambarus clarkii (Girard) from Albufera Lake of Valencia, Spain, under heavy metal treatments

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Mayans, J.; Torreblanca, A.; Del Ramo, J.; Nunez, A.

    1986-06-01

    The American red crayfish Procambarus clarkii, originally from Louisiana (USA) was introduced in Spain in the 70's in the Guadalquivir River swamps. It appeared first randomly and in a more regular basis afterwards since 1978 in the Albufera Lake south of Valencia and in the surrounding rice fields. Albufera lake and surrounding rice fields waters are being subject since the last three decades to very heavy load of sewage, toxic industrial residues including heavy metals and pesticides from the many urban and industrial settlements in the zone. In the present study, the authors have investigated the effect that heavy metals (Chromium, Cadmium and Mercury) have on the oxygen uptake by excised bills of Procambarus clarkii (Girard) coming from the Albufera Lake (Valencia).

  18. Clinical safety and parameters of maximum oxygen uptake (Vo/sub 2/ max) testing in pakistani patients with heart failure

    International Nuclear Information System (INIS)

    Hussain, S.; Kayani, A.M.

    2015-01-01

    To determine the parameters of maximum oxygen uptake (VO2 max) in a Pakistani systolic heart failure cohort and its safety in a clinical setting. Study Design: Descriptive study. Place and Duration of Study: Armed Forces Institute of Cardiology, National Institute of Heart Diseases, Rawalpindi, from June 2011 to January 2013. Methodology: Maximum oxygen uptake test was performed in patients with severe heart failure, who could perform the VO2 max treadmill test. Age, Body Mass Index (BMI) ejection fraction, VO2 max and respiratory exchange ratios and their correlations were determined. Results: Out of 135 patients, 77% (n=104) were males, with a mean age of 45.9 ± 15.7 years. Weight of patients ranged from 30 kg to 107 kg (mean 63.29 ± 13.6 kg); mean BMI was 23.16 ± 4.56 kg/m2. All patients presented with either NYHA class of III (50.3%; n=68) or IV (49.7%; n=67); mean ejection fraction was 22.54 ± 5.7% (10 - 35%, IQ:20 - 25). The VO2 max of the patients ranged from 3 to 32 ml/kg/minute (mean 12.85 ± 4.49 ml/kg/minute). Respiratory exchange ratio was over 1 for all patients (1.12 - 1.96, mean = 1.36 ± 0.187). There was a negative correlation with age (r = -0.204; p = 0.028) whereas a positive correlation was found with exercise time (r = 0.684; p = 0.000), hemoglobin (r = 0.190; p = 0.047) and ejection fraction (r = 0.187 ; p = 0.044). Conclusion: Cardiopulmonary exercise testing in a high-risk heart failure cohort is safe and provides information beyond the routine clinical evaluation of heart failure patients. (author)

  19. Skeletal muscle blood flow and oxygen uptake at rest and during exercise in humans: a PET study with nitric oxide and cyclooxygenase inhibition

    DEFF Research Database (Denmark)

    Heinonen, Ilkka; Saltin, Bengt; Kemppainen, Jukka

    2011-01-01

    The aim of the present study was to determine the effect of nitric oxide and prostanoids on microcirculation and oxygen uptake specifically in the active skeletal muscle by use of positron emission tomography (PET). Healthy males performed 3 five min bouts of light knee-extensor exercise. Skeletal...... muscle blood flow and oxygen uptake were measured at rest and during the exercise using PET with H(2)O(15) and (15)O(2) during: 1) control conditions; 2) nitric oxide synthase (NOS) inhibition by arterial infusion of L-NMMA and 3) combined NOS and cyclooxygenase (COX) inhibition by arterial infusion of L...

  20. Influence of Chironomus riparius (Diptera, Chironomidae) and Tubifex tubifex (Annelida, Oligochaeta) on oxygen uptake by sediments. Consequences of uranium contamination

    Energy Technology Data Exchange (ETDEWEB)

    Lagauzere, S. [Laboratoire de Radioecologie et d' Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire (IRSN), DEI/SECRE/LRE, Cadarache 186, BP 3, F-13115 Cedex, Saint Paul Lez Durance (France)], E-mail: lagauzere@gmail.com; Pischedda, L.; Cuny, P. [Laboratoire de Microbiologie, Geochimie et Ecologie Marines, UMR 6117 CNRS/COM/Universite de la Mediterranee, Campus de Luminy, Case 901, F-13288 Cedex 09, Marseille (France); Gilbert, F. [EcoLab, Laboratoire d' Ecologie Fonctionnelle, UMR 5245 CNRS/INP/Universite Paul Sabatier, 29 Rue Jeanne Marvig, F-31055 Cedex 4, Toulouse (France); Stora, G. [Laboratoire de Microbiologie, Geochimie et Ecologie Marines, UMR 6117 CNRS/COM/Universite de la Mediterranee, Campus de Luminy, Case 901, F-13288 Cedex 09, Marseille (France); Bonzom, J.-M. [Laboratoire de Radioecologie et d' Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire (IRSN), DEI/SECRE/LRE, Cadarache 186, BP 3, F-13115 Cedex, Saint Paul Lez Durance (France)

    2009-04-15

    The diffusive oxygen uptake (DOU) of sediments inhabited by Chironomus riparius and Tubifex tubifex was investigated using a planar oxygen optode device, and complemented by measurements of bioturbation activity. Additional experiments were performed within contaminated sediments to assess the impact of uranium on these processes. After 72 h, the two invertebrate species significantly increased the DOU of sediments (13-14%), and no temporal variation occurred afterwards. Within contaminated sediments, it was already 24% higher before the introduction of the organisms, suggesting that uranium modified the sediment biogeochemistry. Although the two species firstly reacted by avoidance of contaminated sediment, they finally colonized it. Their bioturbation activity was reduced but, for T. tubifex, it remained sufficient to induce a release of uranium to the water column and an increase of the DOU (53%). These results highlight the necessity of further investigations to take into account the interactions between bioturbation, microbial metabolism and pollutants. - This study highlights the ecological importance of bioturbation in metal-contaminated sediments.

  1. Influence of Chironomus riparius (Diptera, Chironomidae) and Tubifex tubifex (Annelida, Oligochaeta) on oxygen uptake by sediments. Consequences of uranium contamination

    International Nuclear Information System (INIS)

    Lagauzere, S.; Pischedda, L.; Cuny, P.; Gilbert, F.; Stora, G.; Bonzom, J.-M.

    2009-01-01

    The diffusive oxygen uptake (DOU) of sediments inhabited by Chironomus riparius and Tubifex tubifex was investigated using a planar oxygen optode device, and complemented by measurements of bioturbation activity. Additional experiments were performed within contaminated sediments to assess the impact of uranium on these processes. After 72 h, the two invertebrate species significantly increased the DOU of sediments (13-14%), and no temporal variation occurred afterwards. Within contaminated sediments, it was already 24% higher before the introduction of the organisms, suggesting that uranium modified the sediment biogeochemistry. Although the two species firstly reacted by avoidance of contaminated sediment, they finally colonized it. Their bioturbation activity was reduced but, for T. tubifex, it remained sufficient to induce a release of uranium to the water column and an increase of the DOU (53%). These results highlight the necessity of further investigations to take into account the interactions between bioturbation, microbial metabolism and pollutants. - This study highlights the ecological importance of bioturbation in metal-contaminated sediments

  2. A COMPARISON BETWEEN VENTILATION AND HEART RATE AS INDICATOR OF OXYGEN UPTAKE DURING DIFFERENT INTENSITIES OF EXERCISE

    Directory of Open Access Journals (Sweden)

    Jacques Prioux

    2010-03-01

    Full Text Available The aim of this study is to compare the relation between ventilation (VE and oxygen uptake (VO2 [VO2=ƒ(VE] and between heart rate (HR and VO2 [VO2=ƒ(HR]. Each one of the subjects performed three types of activities of different intensities (walking without load, walking with load and intermittent work. VO2, VE, and HR were measured continuously by using indirect calorimetry and an electrocardiogram. Linear regressions and coefficients of determination (r² were calculated to compare the relation VO2 =ƒ(VE and VO2 =ƒ(HR for two different regroupings: by session duration (r²session and by subject (r²subject. Results showed that r²session of the relation VO2 =ƒ(VE were significantly higher than those of the relation VO2 =ƒ(HR for steady state activities (walking with or without load during 3 or 6 min, p < 0.01 and for activities without oxygen consumption steady state (walking with or without load during 1 min, p < 0.01 and intermittent work, p < 0.05. VE is more strongly correlated with VO2 than with HR. This is a very promising approach to develop a new method to estimate energy expenditure

  3. Increased cardiac output and maximal oxygen uptake in response to ten sessions of high intensity interval training.

    Science.gov (United States)

    Astorino, Todd A; Edmunds, Ross M; Clark, Amy; King, Leesa; Gallant, Rachael M; Namm, Samantha; Fischer, Anthony; Wood, Kimi A

    2018-01-01

    Increases in maximal oxygen uptake (VO2max) are widely reported in response to completion of high intensity interval training (HIIT), yet the mechanism explaining this result is poorly understood. This study examined changes in VO2max and cardiac output (CO) in response to 10 sessions of low-volume HIIT. Participants included 30 active men and women (mean age and VO2max=22.9±5.4 years and 39.6±5.6 mL/kg/min) who performed HIIT and 30 men and women (age and VO2max=25.7±4.5 years and 40.7±5.2 mL/kg/min) who served as non-exercising controls (CON). High intensity interval training consisted of 6-10 s bouts of cycling per session at 90-110 percent peak power output (PPO) interspersed with 75 s recovery. Before and after training, progressive cycling to exhaustion was completed during which CO, stroke volume (SV), and heart rate (HR) were estimated using thoracic impedance. To confirm VO2max attainment, a verification test was completed after progressive cycling at a work rate equal to 110%PPO. Data demonstrated significant improvements in VO2max (2.71±0.63 L/min to 2.86±0.63 L/min, Psessions of HIIT is due to improvements in oxygen delivery.

  4. Benthic Oxygen Uptake in the Arctic Ocean Margins - A Case Study at the Deep-Sea Observatory HAUSGARTEN (Fram Strait.

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    Cecile Cathalot

    Full Text Available The past decades have seen remarkable changes in the Arctic, a hotspot for climate change. Nevertheless, impacts of such changes on the biogeochemical cycles and Arctic marine ecosystems are still largely unknown. During cruises to the deep-sea observatory HAUSGARTEN in July 2007 and 2008, we investigated the biogeochemical recycling of organic matter in Arctic margin sediments by performing shipboard measurements of oxygen profiles, bacterial activities and biogenic sediment compounds (pigment, protein, organic carbon, and phospholipid contents. Additional in situ oxygen profiles were performed at two sites. This study aims at characterizing benthic mineralization activity along local bathymetric and latitudinal transects. The spatial coverage of this study is unique since it focuses on the transition from shelf to Deep Ocean, and from close to the ice edge to more open waters. Biogeochemical recycling across the continental margin showed a classical bathymetric pattern with overall low fluxes except for the deepest station located in the Molloy Hole (5500 m, a seafloor depression acting as an organic matter depot center. A gradient in benthic mineralization rates arises along the latitudinal transect with clearly higher values at the southern stations (average diffusive oxygen uptake of 0.49 ± 0.18 mmol O2 m-2 d-1 compared to the northern sites (0.22 ± 0.09 mmol O2 m-2 d-1. The benthic mineralization activity at the HAUSGARTEN observatory thus increases southward and appears to reflect the amount of organic matter reaching the seafloor rather than its lability. Although organic matter content and potential bacterial activity clearly follow this gradient, sediment pigments and phospholipids exhibit no increase with latitude whereas satellite images of surface ocean chlorophyll a indicate local seasonal patterns of primary production. Our results suggest that predicted increases in primary production in the Arctic Ocean could induce a larger

  5. EMG and oxygen uptake responses during slow and fast ramp exercise in humans.

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    Scheuermann, Barry W; Tripse McConnell, Joyce H; Barstow, Thomas J

    2002-01-01

    This study examined the relationship between muscle recruitment patterns using surface electromyography (EMG) and the excess O(2) uptake (Ex.V(O(2))) that accompanies slow (SR, 8 W min(-1)) but not fast (FR, 64 W min(-1)) ramp increases in work rate (WR) during exercise on a cycle ergometer. Nine subjects (2 females) participated in this study (25 +/- 2 years, +/- S.E.M.). EMG was obtained from the vastus lateralis and medialis and analysed in the time (root mean square, RMS) and frequency (median power frequency, MDPF) domain. Results for each muscle were averaged to provide an overall response and expressed relative to a maximal voluntary contraction (%MVC). Delta.V(O(2))/DeltaWR was calculated for exercise below (S(1)) and above (S(2)) the lactate threshold (LT) using linear regression. The increase in RMS relative to the increase in WR for exercise below the LT (DeltaRMS/DeltaWR-S(1)) was determined using linear regression. Due to non-linearities in RMS above the LT, DeltaRMS/DeltaWR-S(2) is reported as the difference in RMS (DeltaRMS) and the difference in WR (DeltaWR) at end-exercise and the LT. SR was associated with a higher (P exercise is not associated with the recruitment of additional motor units since Ex.V(O(2)) was observed during SR only. Compared to the progressive decrease in MDPF observed during FR, the MDPF remained relatively constant during SR suggesting that either (i) there was no appreciable recruitment of the less efficient type II muscle fibres, at least in addition to those recruited initially at the onset of exercise, or (ii) the decrease in MDPF associated with fatigue was offset by the addition of a higher frequency of type II fibres recruited to replace the fatigued motor units.

  6. Carbon and nitrogen uptake of calcareous benthic foraminifera along a depth-related oxygen gradient in the OMZ of the Arabian Sea

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    Annekatrin Julie Enge

    2016-02-01

    Full Text Available Foraminifera are an important faunal element of the benthos in oxygen-depleted settings such as Oxygen Minimum Zones (OMZs where they can play a relevant role in the processing of phytodetritus. We investigated the uptake of phytodetritus (labeled with 13C and 15N by cal-careous foraminifera in the 0-1 cm sediment horizon under different oxygen concentrations within the OMZ in the eastern Arabian Sea. The in situ tracer experiments were carried out along a depth transect on the Indian margin over a period of 4 to 10 days. The uptake of phy-todetrital carbon within 4 days by all investigated species shows that phytodetritus is a rele-vant food source for foraminifera in OMZ sediments. The decrease of total carbon uptake from 540 to 1100 m suggests a higher demand for carbon by species in the low-oxygen core region of the OMZ or less food competition with macrofauna. Especially Uvigerinids showed high uptake of phytodetrital carbon at the lowest oxygenated site. Variation in the ratio of phytodetrital carbon to nitrogen between species and sites indicates that foraminiferal carbon and nitrogen use can be decoupled and different nutritional demands are found between spe-cies. Lower ratio of phytodetrital carbon and nitrogen at 540 m could hint for greater demand or storage of food-based nitrogen, ingestion or hosting of bacteria under almost anoxic condi-tions. Shifts in the foraminiferal assemblage structure (controlled by oxygen or food availabil-ity and in the presence of other benthic organisms account for observed changes in the pro-cessing of phytodetritus in the different OMZ habitats. Foraminifera dominate the short-term processing of phytodetritus in the OMZ core but are less important in the lower OMZ bounda-ry region of the Indian margin as biological interactions and species distribution of foraminif-era change with depth and oxygen levels.

  7. Locomotor muscle fatigue does not alter oxygen uptake kinetics during high-intensity exercise

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    James Hopker

    2016-10-01

    Full Text Available The slow component (VO2sc that develops during high-intensity aerobic exercise is thought to be strongly associated with locomotor muscle fatigue. We sought to experimentally test this hypothesis by pre-fatiguing the locomotor muscles used during subsequent high-intensity cycling exercise. Over two separate visits, eight healthy male participants were asked to either perform a non-metabolically stressful 100 intermittent drop-jumps protocol (pre fatigue condition or rest for 33 minutes (control condition according to a random and counterbalanced order. Locomotor muscle fatigue was quantified with 6-second maximal sprints at a fixed pedaling cadence of 90 rev·min-1. Oxygen kinetics and other responses (heart rate, capillary blood lactate concentration and rating of perceived exertion, RPE were measured during two subsequent bouts of 6 min cycling exercise at 50% of the delta between the lactate threshold and VO2max determined during a preliminary incremental exercise test. All tests were performed on the same cycle ergometer. Despite significant locomotor muscle fatigue (P = 0.03, the VO2sc was not significantly different between the pre fatigue (464 ± 301 mL·min-1 and the control (556 ± 223 mL·min-1 condition (P = 0.50. Blood lactate response was not significantly different between conditions (P = 0.48 but RPE was significantly higher following the pre-fatiguing exercise protocol compared with the control condition (P < 0.01 suggesting higher muscle recruitment. These results demonstrate experimentally that locomotor muscle fatigue does not significantly alter the VO2 kinetic response to high intensity aerobic exercise, and challenge the hypothesis that the VO2sc is strongly associated with locomotor muscle fatigue.

  8. Locomotor Muscle Fatigue Does Not Alter Oxygen Uptake Kinetics during High-Intensity Exercise.

    Science.gov (United States)

    Hopker, James G; Caporaso, Giuseppe; Azzalin, Andrea; Carpenter, Roger; Marcora, Samuele M

    2016-01-01

    The [Formula: see text] slow component ([Formula: see text]) that develops during high-intensity aerobic exercise is thought to be strongly associated with locomotor muscle fatigue. We sought to experimentally test this hypothesis by pre-fatiguing the locomotor muscles used during subsequent high-intensity cycling exercise. Over two separate visits, eight healthy male participants were asked to either perform a non-metabolically stressful 100 intermittent drop-jumps protocol (pre-fatigue condition) or rest for 33 min (control condition) according to a random and counterbalanced order. Locomotor muscle fatigue was quantified with 6-s maximal sprints at a fixed pedaling cadence of 90 rev·min -1 . Oxygen kinetics and other responses (heart rate, capillary blood lactate concentration and rating of perceived exertion, RPE) were measured during two subsequent bouts of 6 min cycling exercise at 50% of the delta between the lactate threshold and [Formula: see text] determined during a preliminary incremental exercise test. All tests were performed on the same cycle ergometer. Despite significant locomotor muscle fatigue ( P = 0.03), the [Formula: see text] was not significantly different between the pre-fatigue (464 ± 301 mL·min -1 ) and the control (556 ± 223 mL·min -1 ) condition ( P = 0.50). Blood lactate response was not significantly different between conditions ( P = 0.48) but RPE was significantly higher following the pre-fatiguing exercise protocol compared with the control condition ( P locomotor muscle fatigue does not significantly alter the [Formula: see text] kinetic response to high intensity aerobic exercise, and challenge the hypothesis that the [Formula: see text] is strongly associated with locomotor muscle fatigue.

  9. Relationship between work rate and oxygen uptake in mitochondrial myopathy during ramp-incremental exercise

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    A.C. Gimenes

    2011-04-01

    Full Text Available We determined the response characteristics and functional correlates of the dynamic relationship between the rate (Δ of oxygen consumption ( O2 and the applied power output (work rate = WR during ramp-incremental exercise in patients with mitochondrial myopathy (MM. Fourteen patients (7 males, age 35.4 ± 10.8 years with biopsy-proven MM and 10 sedentary controls (6 males, age 29.0 ± 7.8 years took a ramp-incremental cycle ergometer test for the determination of the O2 on-exercise mean response time (MRT and the gas exchange threshold (GET. The ΔO2/ΔWR slope was calculated up to GET (S1, above GET (S2 and over the entire linear portion of the response (S T. Knee muscle endurance was measured by isokinetic dynamometry. As expected, peak O2 and muscle performance were lower in patients than controls (P O2/ΔWR than controls, especially the S2 component (6.8 ± 1.5 vs 10.3 ± 0.6 mL·min-1·W-1, respectively; P O2/ΔWR (S T and muscle endurance, MRT-O2, GET and peak O2 in MM patients (P O2/ΔWR below 8 mL·min-1·W-1 had severely reduced peak O2 values (O2 had lower ΔO2/ΔWR (P O2/ΔWR is typically reduced in patients with MM, being related to increased functional impairment and higher cardiopulmonary stress.

  10. Low Cardiorespiratory Fitness is Partially Linked to Ventilatory Factors in Obese Adolescents.

    Science.gov (United States)

    Mendelson, Monique; Michallet, Anne-Sophie; Tonini, Julia; Favre-Juvin, Anne; Guinot, Michel; Wuyam, Bernard; Flore, Patrice

    2016-02-01

    To examine the role of ventilatory constraint on cardiorespiratory fitness in obese adolescents. Thirty obese adolescents performed a maximal incremental cycling exercise and were divided into 2 groups based on maximal oxygen uptake (VO2peak): those presenting low (L; n = 15; VO2peak: 72.9 ± 8.6% predicted) or normal (N; n = 15; VO2peak: 113.6 ± 19.2% predicted) cardiorespiratory fitness. Both were compared with a group of healthy controls (C; n = 20; VO2peak: 103.1 ± 11.2% predicted). Ventilatory responses were explored using the flow volume loop method. Cardiorespiratory fitness (VO2peak, in % predicted) was lower in L compared with C and N and was moderately associated with the percent predicted forced vital capacity (FVC) (r = .52; p < .05) in L. At peak exercise, end inspiratory point was lower in L compared with N and C (77.4 ± 8.1, 86.4 ± 7.7, and 89.9 ± 7.6% FVC in L, N, and C, respectively; p < .05), suggesting an increased risk of ventilatory constraint in L, although at peak exercise this difference could be attributed to the lower maximal ventilation in L. Forced vital capacity and ventilatory strategy to incremental exercise slightly differed between N and L. These results suggest a modest participation of ventilatory factors to exercise intolerance.

  11. Effects of high aerobic intensity training in patients with schizophrenia: a controlled trial.

    Science.gov (United States)

    Heggelund, Jørn; Nilsberg, Geir E; Hoff, Jan; Morken, Gunnar; Helgerud, Jan

    2011-09-01

    Patients with schizophrenia have a high risk of cardiovascular disease (CVD). High aerobic intensity training (HIT) improve peak oxygen uptake (VO(2peak)), net mechanical efficiency of walking and risk factors for CVD but has not been investigated in patients with schizophrenia. To investigate effects from HIT on VO(2peak), net mechanical efficiency of walking and risk factors for CVD in patients with schizophrenia. 25 inpatients (F20-29, ICD-10) were allocated to either HIT or playing computer games (CG), 3 days per week for 8 weeks. HIT consisted of 4 × 4-min intervals with 3-min break periods, at 85-95% and 70% of peak heart rate, respectively. 12 and seven patients completed HIT and CG, respectively. The baseline VO(2peak) in both groups combined (n = 19) was 36.8 ± 8.2 ml/kg/min and 3.12 ± 0.55 l/min. The HIT group improved VO(2peak) by 12% from 3.17 ± 0.59 to 3.56 ± 0.68 l/min (P Negative Syndrome Scale (PANSS) and the Calgary Depression Scale for Schizophrenia (CDSS), did not improve in either group. VO(2peak) and net mechanical efficiency of walking improved significantly by 8 weeks of HIT. HIT should be included in rehabilitation in order to improve physical capacity and contribute risk reduction of CVD.

  12. The Effects of Hypobaric Hypoxia on Erythropoiesis, Maximal Oxygen Uptake and Energy Cost of Exercise Under Normoxia in Elite Biathletes

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    Milosz Czuba

    2014-12-01

    Full Text Available The aim of the present study was to evaluate the effects of 3 weeks altitude training according to the HiHiLo (live high-base train high-interval train low procedure as described by Chapman et al. (1998, on erythropoiesis, maximal oxygen uptake and energy cost of exercise under normoxia in elite biathletes. Fifteen male elite biathletes randomly divided into an experimental (H group (n = 7; age 27.1 ± 4.6 years; maximal oxygen uptake (VO2max 66.9 ± 3.3 ml·kg–1·min–1; body height (BH 1.81 ± 0.06 m; body mass (BM 73.1 ± 5.4kg, and a control (C group (n = 8; age 23.2 ± 0.9 years; VO2max 68.2 ± 4.1 ml·kg–1·min–1; BH 1.75 ± 0.03 m; BM 63.1 ± 1.5 kg took part in the study. The H group stayed for 3 weeks at an altitude of 2015 m and performed endurance training on skis four times per week at 3000 m. Additionally, the training protocol included three high-intensity interval sessions at an altitude of 1000 m. The C group followed the same training protocol with skirollers in normoxia at an altitude of 600 m. The HiHiLo protocol applied in our study did not change VO2max or maximal workload (WRmax significantly during the incremental treadmill test in group H. However, the energy cost for selected submaximal workloads in group H was significantly (p < 0.01 reduced compared to group C (-5.7%, -4.4%, -6% vs. -3.5%, -2.1%, -2.4%. Also a significant (p < 0.001 increase in serum EPO levels during the first two weeks of HiHiLo training at 2015 m was observed, associated with a significant (p < 0.05 increase in hemoglobin mass, number of erythrocytes, hematocrit value and percent of reticulocytes compared with initial values (by 6.4%, 5%, 4.6% and 16,6%, respectively. In group C, changes in these variables were not observed. These positive changes observed in our study led to a conclusion that the HiHiLo training method could improve endurance in normoxia, since most of the biathlon competitions are performed at submaximal intensities.

  13. Effect of caffeine on maximal oxygen uptake in wheelchair rugby players: A randomized, placebo-controlled, double-blind study

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    Iva Klimešová

    2017-03-01

    Full Text Available Background: The positive effects of caffeine supplementation on strength-power and endurance performance in healthy athletes have been demonstrated in many studies. A possible mechanism for its ergogenic effect relates to its influence on the central nervous system. Post-traumatic complications in cervical spinal cord injury affect almost all body systems including the nervous system. For this reason, we expect that caffeine will have a different effect of performance in the group of athletes with spinal cord injuries. Objective: To examine the effects of caffeine supplementation on maximal aerobic power in elite wheelchair rugby players. Methods: Seven elite male wheelchair rugby players with complete cervical-level SCI (C4-Th1 were recruited (mean age: 28 ± 5.42 years; mean body mass index: 26 ± 2.84 kg/m2. The effect of caffeine was assessed by an incremental arm ergometer test until volitional exhaustion. The maximal oxygen uptake (VO2max/kg, maximum power (W max/kg, peak heart rate (HR peak, and intensity of perceived exertion (RPE were measured. Participants performed the test twice with a two-week washout period. One hour before each exercise test subjects ingested a capsule of placebo or caffeine (3 mg per kg of body weight. The tests were applied in a double-blind, randomized, repeated-measures, and cross-over design. Wheelchair rugby players were chosen because of the expected high homogeneity of participants - in terms of the type and degree of disability, gender, and age of the players. Results: The monitored parameters were not significantly influenced by caffeine intervention as compared to placebo: VO2max/kg (p = .40, W max/kg (p = .34, HR peak (p = .50 and RPE (p = .50. Conclusions: The current findings suggest that a caffeine dose of 3 mg/kg body mass does not improve oxygen uptake and maximal power in elite wheelchair rugby players.

  14. Comparison of oxygen uptake during and after the execution of resistance exercises and exercises performed on ergometers, matched for intensity

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    Vilaça-Alves José

    2016-12-01

    Full Text Available The aim of this study was to compare the values of oxygen uptake (VO2 during and after strength training exercises (STe and ergometer exercises (Ee, matched for intensity and exercise time. Eight men (24 ± 2.33 years performed upper and lower body cycling Ee at the individual’s ventilatory threshold (VE/VCO2. The STe session included half squats and the bench press which were performed with a load at the individual blood lactate concentration of 4 mmol/l. Both sessions lasted 30 minutes, alternating 50 seconds of effort with a 10 second transition time between upper and lower body work. The averaged overall VO2 between sessions was significantly higher for Ee (24.96 ± 3.6 ml·kg·min-1 compared to STe (21.66 ± 1.77 ml·kg·min-1 (p = 0.035, but this difference was only seen for the first 20 minutes of exercise. Absolute VO2 values between sessions did not reveal differences. There were more statistically greater values in Ee compared to STe, regarding VO2 of lower limbs (25.44 ± 3.84 ml·kg·min-1 versus 21.83 ± 2·24 ml·kg·min-1; p = 0.038 and upper limbs (24.49 ± 3.84 ml·kg·min-1 versus 21.54 ± 1.77 ml·kg·min-1; p = 0.047. There were further significant differences regarding the moment effect (p<0.0001 of both STe and Ee sessions. With respect to the moment × session effect, only VO2 5 minutes into recovery showed significant differences (p = 0.017. In conclusion, although significant increases in VO2 were seen following Ee compared to STe, it appears that the load/intensity, and not the material/equipment used for the execution of an exercise, are variables that best influence oxygen uptake.

  15. Time Trials Versus Time-to-Exhaustion Tests: Effects on Critical Power, W', and Oxygen-Uptake Kinetics.

    Science.gov (United States)

    Karsten, Bettina; Baker, Jonathan; Naclerio, Fernando; Klose, Andreas; Bianco, Antonino; Nimmerichter, Alfred

    2018-02-01

    To investigate single-day time-to-exhaustion (TTE) and time-trial (TT) -based laboratory tests values of critical power (CP), W prime (W'), and respective oxygen-uptake-kinetic responses. Twelve cyclists performed a maximal ramp test followed by 3 TTE and 3 TT efforts interspersed by 60 min recovery between efforts. Oxygen uptake ( V ˙ O 2 ) was measured during all trials. The mean response time was calculated as a description of the overall [Formula: see text]-kinetic response from the onset to 2 min of exercise. TTE-determined CP was 279 ± 52 W, and TT-determined CP was 276 ± 50 W (P = .237). Values of W' were 14.3 ± 3.4 kJ (TTE W') and 16.5 ± 4.2 kJ (TT W') (P = .028). While a high level of agreement (-12 to 17 W) and a low prediction error of 2.7% were established for CP, for W' limits of agreements were markedly lower (-8 to 3.7 kJ), with a prediction error of 18.8%. The mean standard error for TTE CP values was significantly higher than that for TT CP values (2.4% ± 1.9% vs 1.2% ± 0.7% W). The standard errors for TTE W' and TT W' were 11.2% ± 8.1% and 5.6% ± 3.6%, respectively. The [Formula: see text] response was significantly faster during TT (~22 s) than TTE (~28 s). The TT protocol with a 60-min recovery period offers a valid, time-saving, and less error-filled alternative to conventional and more recent testing methods. Results, however, cannot be transferred to W'.

  16. Time course for the recovery of physical performance, blood hemoglobin, and ferritin content after blood donation

    DEFF Research Database (Denmark)

    Ziegler, Andreas K; Grand, Johannes; Stangerup, Ida

    2015-01-01

    BACKGROUND: It is widely accepted that blood donation negatively affects endurance performance, but data on physical recovery after a standard blood donation are scarce. This study aimed to elucidate the temporary impact of blood donation on endurance performance, measured as peak oxygen uptake (VO......2peak ) and time trial (TT) performance. STUDY DESIGN AND METHODS: VO2peak , TT performance, blood, iron, and anthropometric variables were determined before (baseline) and 3, 7, 14, and 28 days after blood donation in 19 healthy men. RESULTS: VO2peak was reduced by 6.5% from 49.7 ± 2 m......L/kg/min at baseline to 46.3 ± 2 mL/kg/min on Day 3 (p donation. Blood hemoglobin (Hb) concentration declined 7.9% from 9.3 ± 0.11 mmol...

  17. Analysis of heart rate and oxygen uptake kinetics studied by two different pseudo-random binary sequence work rate amplitudes.

    Science.gov (United States)

    Drescher, U; Koschate, J; Schiffer, T; Schneider, S; Hoffmann, U

    2017-06-01

    The aim of the study was to compare the kinetics responses of heart rate (HR), pulmonary (V˙O 2 pulm) and predicted muscular (V˙O 2 musc) oxygen uptake between two different pseudo-random binary sequence (PRBS) work rate (WR) amplitudes both below anaerobic threshold. Eight healthy individuals performed two PRBS WR protocols implying changes between 30W and 80W and between 30W and 110W. HR and V˙O 2 pulm were measured beat-to-beat and breath-by-breath, respectively. V˙O 2 musc was estimated applying the approach of Hoffmann et al. (Eur J Appl Physiol 113: 1745-1754, 2013) considering a circulatory model for venous return and cross-correlation functions (CCF) for the kinetics analysis. HR and V˙O 2 musc kinetics seem to be independent of WR intensity (p>0.05). V˙O 2 pulm kinetics show prominent differences in the lag of the CCF maximum (39±9s; 31±4s; p<0.05). A mean difference of 14W between the PRBS WR amplitudes impacts venous return significantly, while HR and V˙O 2 musc kinetics remain unchanged. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Influence of silicon treatment on antimony uptake and translocation in rice genotypes with different radial oxygen loss.

    Science.gov (United States)

    Zhang, Liping; Yang, Qianqian; Wang, Shiliang; Li, Wanting; Jiang, Shaoqing; Liu, Yan

    2017-10-01

    Antimony (Sb) pollution in soil may have a negative impact on the health of people consuming rice. This study investigated the effect of silicon (Si) application on rice biomass, iron plaque formation, and Sb uptake and speciation in rice plants with different radial oxygen loss (ROL) using pot experiments. The results demonstrated that Si addition increased the biomass of straw and grain, but had no obvious impact on the root biomass. Indica genotypes with higher ROL underwent greater iron plaque formation and exhibited more Sb sequestration in iron plaque. Silicon treatments increased iron levels in iron plaque from the different genotypes but decreased the total Sb concentration in root, straw, husk, and grain. In addition, Si treatment reduced the inorganic Sb concentrations but slightly increased the trimethylantimony (TMSb) concentrations in rice straw. Moreover, rice straw from hybrid genotypes accumulated higher concentrations of TMSb and inorganic Sb than that from indica genotypes. The conclusions from this study indicate that Sb contamination in rice can be efficiently reduced by applying Si treatment and selecting genotypes with high ROL. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. 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.

  20. Oxygen uptake in water polo, comparison and agreement in cycle ergometer and eggbeater kick: A pilot study

    Directory of Open Access Journals (Sweden)

    Ligia Ignêz Engelmann

    Full Text Available Abstract The aim of this study was to compare and verify the agreement of maximal oxygen uptake (VO2 max values obtained from tests on land and in water. Twelve recreational water polo players (30.5 ± 7.7 years; 79.2 ± 7.2 kg body mass; 179.1 ± 5.9 cm height were assessed in two phases: (1 in laboratory with maximal test on a cycle ergometer and (2 in a swimming pool with maximal test in eggbeater kick. Maximum values obtained in the two tests (respectively, cycle ergometer, and eggbeater kick: VO2 max = 40.2 ± 2.7 ml.kg-1.min-1 and 38.4 ± 5.7 ml.kg-1.min-1; RER = 1.17 ± 0.08 and 1.19 ± 0.12; HR max = 181.4 ± 11.7 bpm and 179 ± 11.7 bpm; IEP = 20 and 20 did not show significant differences. According to the Bland-Altman analyses, there were acceptable limits of agreement between the two tests (land and water. Therefore, it can be concluded that the eggbeater kick test is a specific and valid protocol to asses VO2 max in water polo players.

  1. Relationship between oxygen uptake slow component and surface EMG during heavy exercise in humans: influence of pedal rate.

    Science.gov (United States)

    Vercruyssen, Fabrice; Missenard, Olivier; Brisswalter, Jeanick

    2009-08-01

    The aim of this study was to test the hypothesis that extreme pedal rates contributed to the slow component of oxygen uptake (VO(2) SC) in association with changes in surface electromyographic (sEMG) during heavy-cycle exercise. Eight male trained cyclists performed two square-wave transitions at 50 and 110 rpm at a work rate that would elicit a VO(2) corresponding to 50% of the difference between peak VO(2) and the ventilatory threshold. Pulmonary gas exchange was measured breath-by-breath and sEMG was obtained from the vastus lateralis and medialis muscles. Integrated EMG flow (QiEMG) and mean power frequency (MPF) were computed. The relative amplitude of the VO(2) SC was significantly higher during the 110-rpm bout (556+/-186 ml min(-1), Pexercise only during the 110-rpm bout and were associated with the greater amplitude of the VO(2) SC observed for this condition (Pmotor units recruitment pattern, muscle energy turnover and muscle temperature have been suggested to explain the different VO(2) SC to heavy pedal rate bouts.

  2. Aspects of the uptake of dissolved oxygen in Cabiúnas and Imboassica Lagoons (Macaé, RJ

    Directory of Open Access Journals (Sweden)

    Paulo R. Brum

    1999-01-01

    Full Text Available In this work, we describe qualitative and quantitative aspects of the cycling of detritus of aquatic macrophytes and carbohydrates in two coastal lagoons of the northeastern part of the State of Rio de Janeiro. Samples of water of the Imboassica and Cabiúnas lagoons were enriched with sucrose. Samples of water of the Cabiúnas lagoon were also utilized to arrange mineralization chambers with fragments of three species of aquatic macrophytes found in these lagoons (Typha domingensis, Potamogeton stenostachys and Nymphaea ampla. Following that, the bottles were aerated and incubated (in the laboratory for a period of 8 days. The concentrations of dissolved oxygen, the pH, the electrical conductivity and the temperature were daily measured. The anaerobic processes were inhibited by periodical aeration of the bottles. The results suggested that the mineralization process in Imboassica lagoon was more efficient; in Cabiúnas lagoon the process of immobilization of the organic matter was dominant. In the short term, maximum oxygen uptake occurred in the mineralization of N. ampla, followed by the mineralization of P. stenostachys and of T. domingensis. However, it was estimated that in long term the mineralization of P. stenostachys showed a greater oxygen uptake.Nesta pesquisa, descrevemos aspectos qualitativos e quantitativos da ciclagem de detritos de macrófitas aquáticas e carboidratos em duas lagoas costeiras do nordeste do Estado do Rio de Janeiro. Amostras de água das lagoas Imboassica e Cabiúnas foram enriquecidas com sacarose. Amostras de água da lagoa Cabiúnas foram também utilizadas para a montagem de câmaras de mineralização com fragmentos de três espécies de macrófitas aquáticas encontradas nestas lagoas (Typha domingensis, Potamogeton stenostachys e Nymphaea ampla. Em seguida, as garrafas foram aeradas e incubadas (no laboratório por um período de 8 dias. As concentrações de oxigênio dissolvido, o pH, a condutividade

  3. The relative importance of skin oxygen uptake in the naturally buried plaice, Pleuronectes platessa, exposed to graded hypoxia

    DEFF Research Database (Denmark)

    Steffensen, J F; Lomholt, J P; Johansen, K

    1981-01-01

    Cutaneous O2-uptake has been estimated in plaice, Pleuronectes platessa, naturally buried in sediment as the difference between total O2-uptake, measured in a flow-through respirometer, and branchial O2-uptake calculated from direct and continuous recordings of gill water flow and O2-extraction...

  4. Using Argo-O2 data to examine the impact of deep-water formation events on oxygen uptake in the Labrador Sea

    Science.gov (United States)

    Wolf, M. K.; Hamme, R. C.; Gilbert, D.; Yashayaev, I.

    2016-02-01

    Deep-water formation allows the deep ocean to communicate with the atmosphere, facilitating exchanges of heat as well as important gases such as CO2 and oxygen. The Labrador Sea is the most studied location of deep convection in the North Atlantic Ocean and a strong contributor to the global thermohaline circulation. Since there are no internal sources of oxygen below the euphotic zone, deep-water formation is vital for oxygen transport to the deep ocean. Recent studies document large interannual variability in the strength and depth of convection in the Labrador Sea, from mixed layers of 100m to greater than 1000m. A weakening of this deep convection starves the deep ocean of oxygen, disrupting crucial deep sea biological processes, as well as reducing oceanic CO2 uptake and ocean circulation. We used data from the extensive Argo float network to examine these deep-water formation events in the Labrador Sea. The oxygen optodes onboard many Argo floats suffer from biases whose amplitude must be determined; therefore we investigated and applied various optode calibration methods. Using calibrated vertical profiles of oxygen, temperature, and salinity, we observed the timing, magnitude, and location of deep convection, restratification, and spring phytoplankton blooms. In addition, we used surface oxygen values along with NCEP wind speeds to calculate the air-sea oxygen flux using a range of air-sea gas exchange parameterizations. We then compared this oxygen flux to the rate of change of the measured oxygen inventory. Where the inventory and flux did not agree, we identified other oceanic processes such as biological activity or lateral advection of water masses occurring, or advection of the float itself into a new area. The large role that horizontal advection of water or the float has on oxygen uptake and cycling leads us to conclude that this data cannot be easily interpreted as a 1-D system. Oxygen exchanges with the atmosphere at a faster rate than CO2, is

  5. Reassessment of FDG uptake in tumor cells: High FDG uptake as a reflection of oxygen-independent glycolysis dominant energy production

    Energy Technology Data Exchange (ETDEWEB)

    Waki, A.; Fujibayashi, Y.; Yonekura, Y.; Sadato, N.; Ishii, Y.; Yokoyama, A

    1997-10-01

    To determine appropriate use of 2-[{sup 18}F]-fluoro-2-deoxy-D-glucose (FDG) in the diagnosis of malignant tumors, the mechanism of enhanced FDG uptake in tumor cells was reassessed using in vitro cultured cell lines and {sup 3}H-deoxyglucose (DG), in combination with possible parameters of aerobic and anaerobic energy production. The high DG uptake in the tumor cells reflected the dependency of energy production on anaerobic glycolysis, and paradoxically on low levels of aerobic oxidative phosphorylation in mitochondria. We discuss here factors underlying anaerobic glycolysis in tumor cells.

  6. The effects of high-Dk rigid contact lens center thickness, material permeability, and blinking on the oxygen uptake of the human cornea.

    Science.gov (United States)

    Gardner, Hope Patterson; Fink, Barbara A; Mitchell, Lynn G; Hill, Richard M

    2005-06-01

    The human corneal oxygen uptake responses associated with the static (nonblinking) and dynamic (blinking) wear of five rigid gas-permeable materials with high oxygen permeabilities were determined for three different center thicknesses and compared with the responses for the normal open eye and severe hypoxic stress (static wear of polymethylmethacrylate). Corneal oxygen uptake rates were measured with a Clark-type polarographic electrode during two sessions with each of 10 human subjects. Measurements were made on the right eye for the normal open eye (air) and after 5 minutes of static and dynamic wear of polymethylmethacrylate and five rigid gas-permeable contact lens materials: Fluoroperm 92 (paflufocon A, Dk = 92), Fluoroperm 151 (paflufocon D, Dk = 151), 1992 Menicon SF-P (melafocon A, Dk = 102), 1995 Menicon SF-P (melafocon A, Dk = 159), and Menicon Z (tisilfocon A, Dk = 163-250). Lenses were manufactured in three different center thicknesses (0.12, 0.16, and 0.20 mm), with all other parameters remaining constant. Repeated-measures analysis of variance was used and included lens material (five levels), blinking condition (two levels), and lens thickness (three levels) as within-subject effects. Significant differences were found in corneal oxygen responses to lens material (p Dk rigid lens materials studied here, moderate changes in lens thickness or material permeability may result in modest differences in corneal hypoxic relief, whereas blinking results in no significant improvement to corneal oxygenation.

  7. Oxygen uptake and body composition after aquatic physical training in women with fibromyalgia: a randomized controlled trial.

    Science.gov (United States)

    Andrade, Carolina P; Zamunér, Antonio R; Forti, Meire; França, Thalita F; Tamburús, Nayara Y; Silva, Ester

    2017-10-01

    Aquatic physical training (APT) has been strongly recommended to improve symptoms in fibromyalgia syndrome (FMS). However, its effects on body composition and whether lean body mass (LBM) directly influences the aerobic functional capacity of this population are still not clear. To investigate whether APT can help improve body composition and increase the aerobic functional capacity in women with FMS, and whether oxygen uptake (VO2) related to LBM can better quantify the functional capacity of this population. Randomized controlled trial. The Federal University of São Carlos, São Paulo, Brazil. Fifty-four women with FMS were randomly assigned to trained group (TG, N.=27) or control group (CG, N.=27). All women underwent cardiopulmonary exercise test (CPET) to assess oxygen consumption at ventilatory anaerobic threshold (VAT) and at peak exercise, and also to assess body composition. The TG was submitted to APT program, held twice a week for 16 weeks. The exercise intensity was adapted throughout the sessions in order to keep heart rate and ratings of perceived exertion achieved at VAT. After APT, body composition was not significantly different between groups (TG and CG). In VAT only TG showed increased VO2 related to LBM, since in peak CPET, VO2 in absolute units, VO2 related to total body mass (TBM), VO2 related to LBM and power showed significant differences. Significant difference between VO2 related to TBM and VO2 related to baseline LBM and after 16 weeks of follow-up, both in VAT as in peak CPET in both groups. Significant difference between VO2 related to TBM and VO2 related to LBM at VAT and at peak CPET in both groups at baseline and after 16 weeks of follow-up was observed. APT with standardized intensities did not cause significant changes in body composition, but was effective in promoting increased VO2 at peak CPET in women with FMS. However, VO2 related to LBM more accurately reflected changes in aerobic functional capacity at VAT level after to

  8. Seasonal variations in body composition, maximal oxygen uptake, and gas exchange threshold in cross-country skiers.

    Science.gov (United States)

    Polat, Metin; Korkmaz Eryılmaz, Selcen; Aydoğan, Sami

    2018-01-01

    In order to ensure that athletes achieve their highest performance levels during competitive seasons, monitoring their long-term performance data is crucial for understanding the impact of ongoing training programs and evaluating training strategies. The present study was thus designed to investigate the variations in body composition, maximal oxygen uptake (VO 2max ), and gas exchange threshold values of cross-country skiers across training phases throughout a season. In total, 15 athletes who participate in international cross-country ski competitions voluntarily took part in this study. The athletes underwent incremental treadmill running tests at 3 different time points over a period of 1 year. The first measurements were obtained in July, during the first preparation period; the second measurements were obtained in October, during the second preparation period; and the third measurements were obtained in February, during the competition period. Body weight, body mass index (BMI), body fat (%), as well as VO 2max values and gas exchange threshold, measured using V-slope method during the incremental running tests, were assessed at all 3 time points. The collected data were analyzed using SPSS 20 package software. Significant differences between the measurements were assessed using Friedman's twoway variance analysis with a post hoc option. The athletes' body weights and BMI measurements at the third point were significantly lower compared with the results of the second measurement ( p exchange threshold, running speed at the gas exchange threshold, VO 2max , amount of oxygen consumed at gas exchange threshold level (VO 2GET ), maximal heart rate (HR max ), and heart rate at gas exchange threshold level (HR GET ) values did not significantly differ between the measurement time points ( p >0.05). VO 2max and gas exchange threshold values recorded during the third measurements, the timing of which coincided with the competitive season of the cross-country skiers

  9. Non-linear relationship between oxygen uptake and power output in the Astrand nomogram-old data revisited.

    Science.gov (United States)

    Zoladz, J A; Szkutnik, Z; Majerczak, J; Duda, K; Pedersen, P K

    2007-06-01

    For the last decade there have been considerable discussion concerning the linearity / non-linearity of the oxygen uptake (V(O2)) - power output (W) relationship with strong experimental evidence of non-linearity provided mainly by breath-by-breath measurements. In this study, we attempted to answer the question whether the V(O2) - W relationship in the Astrand nomogram, as presented in the Textbook of Work Physiology, P.-O. Astrand et al. (2003), page 281, based on the Douglas bag method, is indeed linear, as stated by the authors before, or if a change point in V(O2), described by Zoladz et al. (1998) Eur J Appl Physiol 78: 369-377, can possibly be detected in those data. The V(O2) - W data were taken from the Astrand nomogram referenced above and from the Table 9.5 on page 282 in the same reference and tested for the presence of the change point in V(O2), using our two-phase model (see the reference above). In the first phase, a linear V(O2) - W relationship was assumed, whereas in the second one (above the so-called change point) an additional increase in V(O2) above the values expected from the linear model was allowed. It was found that in the data taken from the Astrand nomogram (data for men), as well as in the data taken from the Table 9.5, statistically significant change points in V(O2) were present at the power output of 150 W. The documentation of the presence of a change point in the V(O2) - W relationship in the Astrand data provides further evidence for the existence of a non-linearity in the V(O2) - W relationship in incremental exercise tests of humans, also in V(O2) data based upon the Douglas bag method.

  10. The correlation between running economy and maximal oxygen uptake: cross-sectional and longitudinal relationships in highly trained distance runners.

    Science.gov (United States)

    Shaw, Andrew J; Ingham, Stephen A; Atkinson, Greg; Folland, Jonathan P

    2015-01-01

    A positive relationship between running economy and maximal oxygen uptake (V̇O2max) has been postulated in trained athletes, but previous evidence is equivocal and could have been confounded by statistical artefacts. Whether this relationship is preserved in response to running training (changes in running economy and V̇O2max) has yet to be explored. This study examined the relationships of (i) running economy and V̇O2max between runners, and (ii) the changes in running economy and V̇O2max that occur within runners in response to habitual training. 168 trained distance runners (males, n = 98, V̇O2max 73.0 ± 6.3 mL∙kg-1∙min-1; females, n = 70, V̇O2max 65.2 ± 5.9 mL kg-1∙min-1) performed a discontinuous submaximal running test to determine running economy (kcal∙km-1). A continuous incremental treadmill running test to volitional exhaustion was used to determine V̇O2max 54 participants (males, n = 27; females, n = 27) also completed at least one follow up assessment. Partial correlation analysis revealed small positive relationships between running economy and V̇O2max (males r = 0.26, females r = 0.25; Peconomy and V̇O2max in response to habitual training (r = 0.35; Peconomy and V̇O2max in highly trained distance runners. With >85% of the variance in these parameters unexplained by this relationship, these findings reaffirm that running economy and V̇O2max are primarily determined independently.

  11. Reversible uptake of molecular oxygen by heteroligand Co(II)-L-α-amino acid-imidazole systems: equilibrium models at full mass balance.

    Science.gov (United States)

    Pająk, Marek; Woźniczka, Magdalena; Vogt, Andrzej; Kufelnicki, Aleksander

    2017-09-19

    The paper examines Co(II)-amino acid-imidazole systems (where amino acid = L-α-amino acid: alanine, asparagine, histidine) which, when in aqueous solutions, activate and reversibly take up dioxygen, while maintaining the structural scheme of the heme group (imidazole as axial ligand and O 2 uptake at the sixth, trans position) thus imitating natural respiratory pigments such as myoglobin and hemoglobin. The oxygenated reaction shows higher reversibility than for Co(II)-amac systems with analogous amino acids without imidazole. Unlike previous investigations of the heteroligand Co(II)-amino acid-imidazole systems, the present study accurately calculates all equilibrium forms present in solution and determines the [Formula: see text]equilibrium constants without using any simplified approximations. The equilibrium concentrations of Co(II), amino acid, imidazole and the formed complex species were calculated using constant data obtained for analogous systems under oxygen-free conditions. Pehametric and volumetric (oxygenation) studies allowed the stoichiometry of O 2 uptake reaction and coordination mode of the central ion in the forming oxygen adduct to be determined. The values of dioxygen uptake equilibrium constants [Formula: see text] were evaluated by applying the full mass balance equations. Investigations of oxygenation of the Co(II)-amino acid-imidazole systems indicated that dioxygen uptake proceeds along with a rise in pH to 9-10. The percentage of reversibility noted after acidification of the solution to the initial pH ranged within ca 30-60% for alanine, 40-70% for asparagine and 50-90% for histidine, with a rising tendency along with the increasing share of amino acid in the Co(II): amino acid: imidazole ratio. Calculations of the share of the free Co(II) ion as well as of the particular complex species existing in solution beside the oxygen adduct (regarding dioxygen bound both reversibly and irreversibly) indicated quite significant values for the

  12. Measuring Steady-State Oxygen Uptake during the 6-Min Walk Test in Adults with Cerebral Palsy: Feasibility and Construct Validity

    Science.gov (United States)

    Maltais, Desiree B.; Robitaille, Nancy-Michelle; Dumas, Francine; Boucher, Normand; Richards, Carol L.

    2012-01-01

    This study evaluated the feasibility of measuring steady-state oxygen uptake (V[Combining Dot Above]O[subscript 2]) during the 6-min walk test (6MWT) in adults with cerebral palsy (CP) who walk without support and whether there is construct validity for net 6MWT V[Combining Dot Above]O[subscript 2] as a measure of their walking ability.…

  13. Maximum Plant Uptakes for Water, Nutrients, and Oxygen Are Not Always Met by Irrigation Rate and Distribution in Water-based Cultivation Systems.

    Science.gov (United States)

    Blok, Chris; Jackson, Brian E; Guo, Xianfeng; de Visser, Pieter H B; Marcelis, Leo F M

    2017-01-01

    Growing on rooting media other than soils in situ -i.e., substrate-based growing- allows for higher yields than soil-based growing as transport rates of water, nutrients, and oxygen in substrate surpass those in soil. Possibly water-based growing allows for even higher yields as transport rates of water and nutrients in water surpass those in substrate, even though the transport of oxygen may be more complex. Transport rates can only limit growth when they are below a rate corresponding to maximum plant uptake. Our first objective was to compare Chrysanthemum growth performance for three water-based growing systems with different irrigation. We compared; multi-point irrigation into a pond (DeepFlow); one-point irrigation resulting in a thin film of running water (NutrientFlow) and multi-point irrigation as droplets through air (Aeroponic). Second objective was to compare press pots as propagation medium with nutrient solution as propagation medium. The comparison included DeepFlow water-rooted cuttings with either the stem 1 cm into the nutrient solution or with the stem 1 cm above the nutrient solution. Measurements included fresh weight, dry weight, length, water supply, nutrient supply, and oxygen levels. To account for differences in radiation sum received, crop performance was evaluated with Radiation Use Efficiency (RUE) expressed as dry weight over sum of Photosynthetically Active Radiation. The reference, DeepFlow with substrate-based propagation, showed the highest RUE, even while the oxygen supply provided by irrigation was potentially growth limiting. DeepFlow with water-based propagation showed 15-17% lower RUEs than the reference. NutrientFlow showed 8% lower RUE than the reference, in combination with potentially limiting irrigation supply of nutrients and oxygen. Aeroponic showed RUE levels similar to the reference and Aeroponic had non-limiting irrigation supply of water, nutrients, and oxygen. Water-based propagation affected the subsequent

  14. Skeletal muscle bioenergetics during all-out exercise: mechanistic insight into the oxygen uptake slow component and neuromuscular fatigue.

    Science.gov (United States)

    Broxterman, Ryan M; Layec, Gwenael; Hureau, Thomas J; Amann, Markus; Richardson, Russell S

    2017-05-01

    and skeletal muscle bioenergetics underlying all-out exercise performance are unclear. This study revealed an increase in oxidative ATP synthesis rate gain and the ATP cost of contraction during all-out exercise. Furthermore, peripheral fatigue was related to the perturbation in pH and deprotonated phosphate ion. These findings support the concept that the oxygen uptake slow component arises from within active skeletal muscle and that skeletal muscle force generating capacity is linked to the intramuscular metabolic milieu.

  15. 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...

  16. Muscle injury after low-intensity downhill running reduces running economy.

    Science.gov (United States)

    Baumann, Cory W; Green, Michael S; Doyle, J Andrew; Rupp, Jeffrey C; Ingalls, Christopher P; Corona, Benjamin T

    2014-05-01

    Contraction-induced muscle injury may reduce running economy (RE) by altering motor unit recruitment, lowering contraction economy, and disturbing running mechanics, any of which may have a deleterious effect on endurance performance. The purpose of this study was to determine if RE is reduced 2 days after performing injurious, low-intensity exercise in 11 healthy active men (27.5 ± 5.7 years; 50.05 ± 1.67 VO2peak). Running economy was determined at treadmill speeds eliciting 65 and 75% of the individual's peak rate of oxygen uptake (VO2peak) 1 day before and 2 days after injury induction. Lower extremity muscle injury was induced with a 30-minute downhill treadmill run (6 × 5 minutes runs, 2 minutes rest, -12% grade, and 12.9 km·h(-1)) that elicited 55% VO2peak. Maximal quadriceps isometric torque was reduced immediately and 2 days after the downhill run by 18 and 10%, and a moderate degree of muscle soreness was present. Two days after the injury, steady-state VO2 and metabolic work (VO2 L·km(-1)) were significantly greater (4-6%) during the 65% VO2peak run. Additionally, postinjury VCO2, VE and rating of perceived exertion were greater at 65% but not at 75% VO2peak, whereas whole blood-lactate concentrations did not change pre-injury to postinjury at either intensity. In conclusion, low-intensity downhill running reduces RE at 65% but not 75% VO2peak. The results of this study and other studies indicate the magnitude to which RE is altered after downhill running is dependent on the severity of the injury and intensity of the RE test.

  17. CHANGES IN PAIN PERCEPTION IN WOMEN DURING AND FOLLOWING AN EXHAUSTIVE INCREMENTAL CYCLING EXERCISE

    Directory of Open Access Journals (Sweden)

    Daniel G. Drury

    2005-09-01

    Full Text Available Exercise has been found to alter pain sensitivity with a hypoalgesic response (i.e., diminished sensitivity to pain typically reported during and/or following high intensity exercise. Most of this research, however, has involved the testing of men. Thus, the purpose of the following investigation was to examine changes in pain perception in women during and following exercise. Seventeen healthy female subjects (age 20.47±.87; VO2 peak 36.77± 4.95 volunteered to undergo pain assessment prior to, during, and after a graded exhaustive VO2 peak cycling challenge. Heart Rate (HR and Oxygen Uptake (VO2 were monitored along with electro-diagnostic assessments of Pain Threshold (PT and Pain Tolerance (PTOL at: 1 baseline (B, 2 during exercise (i.e., 120 Watts, 3 at exhaustive intensity (VO2 peak, and 4 10 minutes into recovery (R. Data were analyzed using repeated measures ANOVA to determine differences across trials. Significant differences in PT and PTOL were found across trials (PT, p = 0.0043; PTOL p = 0.0001. Post hoc analyses revealed that PT were significantly elevated at VO2 peak in comparison to B (p = 0.007, 120 Watts (p = 0.0178 and R (p = 0.0072. PTOL were found to be significantly elevated at 120 Watts (p = 0.0247, VO2 peak (p < 0.001, and R (p = 0.0001 in comparison to B. In addition, PTOL were found to be significantly elevated at VO2 peak in comparison to 120 Watts (p = 0.0045. It is concluded that exercise-induced hypoalgesia occurs in women during and following exercise, with the hypoalgesic response being most pronounced following exhaustive exercise

  18. Abolition of reflex bradycardia by cardiac vagotomy has no effect on the regulation of oxygen uptake by Atlantic cod in progressive hypoxia

    DEFF Research Database (Denmark)

    McKenzie, David; Skov, Peter Vilhelm; Taylor, E.W.T.

    2009-01-01

    The functional significance of chemoreflexive hypoxic bradycardia was explored in Atlantic cod Gadus morhua L. (mean mass similar to 800 g, acclimated to a seawater temperature of 11 degrees C) by investigating responses to progressive hypoxia following section of the cardiac branches of cranial...... nerve X Cardiac denervation had no effect on oxygen uptake rate (M-O2), gill ventilation rate (f(G)) or opercular pressure amplitude (P-OP) under normoxic conditions, but caused a significant increase in heart rate (f(H)), to 50 +/- 1 beats min(-1) by comparison to 40 +/- 2 beats min(-1) in sham...

  19. Fish embryos on land: terrestrial embryo deposition lowers oxygen uptake without altering growth or survival in the amphibious fish Kryptolebias marmoratus.

    Science.gov (United States)

    Wells, Michael W; Turko, Andy J; Wright, Patricia A

    2015-10-01

    Few teleost fishes incubate embryos out of water, but the oxygen-rich terrestrial environment could provide advantages for early growth and development. We tested the hypothesis that embryonic oxygen uptake is limited in aquatic environments relative to air using the self-fertilizing amphibious mangrove rivulus, Kryptolebias marmoratus, which typically inhabits hypoxic, water-filled crab burrows. We found that adult mangrove rivulus released twice as many embryos in terrestrial versus aquatic environments and that air-reared embryos had accelerated developmental rates. Surprisingly, air-reared embryos consumed 44% less oxygen and possessed larger yolk reserves, but attained the same mass, length and chorion thickness. Water-reared embryos moved their opercula ∼2.5 more times per minute compared with air-reared embryos at 7 days post-release, which probably contributed to the higher rates of oxygen uptake and yolk utilization we observed. Genetically identical air- and water-reared embryos from the same parent were raised to maturity, but the embryonic environment did not affect growth, reproduction or emersion ability in adults. Therefore, although aspects of early development were plastic, these early differences were not sustained into adulthood. Kryptolebias marmoratus embryos hatched out of water when exposed to aerial hypoxia. We conclude that exposure to a terrestrial environment reduces the energetic costs of development partly by reducing the necessity of embryonic movements to dispel stagnant boundary layers. Terrestrial incubation of young would be especially beneficial to amphibious fishes that occupy aquatic habitats of poor water quality, assuming low terrestrial predation and desiccation risks. © 2015. Published by The Company of Biologists Ltd.

  20. Effect of an insect juvenile hormone analogue, Fenoxycarb on development and oxygen uptake by larval lobsters Homarus gammarus (L.).

    Science.gov (United States)

    Arnold, Katie E; Wells, Colin; Spicer, John I

    2009-04-01

    Little attention has been focused on the effect of anthropogenic compounds that disrupt the endocrine systems in crustaceans. Consequently, this study investigated the effects of the juvenile hormone analogue (JHA), Fenoxycarb on selected physiological and developmental processes of the zoeal stages in the European lobster, Homarus gammarus. Chronic exposure to Fenoxycarb (50microg L(-1)) resulted in a significant (p < 0.05) reduction in moult frequency and size at moult. Fenoxycarb exposure extended zoeal duration between zoea I to II (p<0.05) and resulted in total inhibition of the moult from zoea II to III. Significantly greater rates of O2 uptake were observed in Fenoxycarb-exposed larvae in comparison with controls (p<0.05). All rates of O2 uptake decreased significantly between 7 and 12d of exposure (p<0.05). At 12d, exposure to the solvent control no longer influenced rates of O2 uptake, but it was not possible to attribute increased O2 uptake to Fenoxycarb exposure directly, as treated individuals did not moult beyond zoea III. The low exposure concentrations of Fenoxycarb, comparable to those used in plant protection, resulted in endocrine disrupted responses in H. gammarus (albeit with little clear, demonstrable effect on metabolism) a finding that could have important ecological and commercial implications.

  1. Oxygen uptake kinetics during and after exercise are useful markers of coronary artery disease in patients with exercise electrocardiography suggesting myocardial ischemia

    International Nuclear Information System (INIS)

    Tajima, Akihiko; Ohkoshi, Nobuyuki; Kawara, Tokuhiro; Aizawa, Tadanori; Itoh, Haruki; Maeda, Tomoko; Osada, Naohiko; Omiya, Kazuto; Wasserman, K.

    2009-01-01

    The aim of the current study was to determine if the slowed exercise oxygen uptake (VO 2 ) kinetics, which is developed by myocardial ischemia, would be accompanied by delayed recovery VO 2 kinetics in patients with coronary artery disease (CAD). Thirty-seven patients with significant ST depression during treadmill exercise underwent cardiopulmonary exercise testing with cycle ergometer. Measurements performed are the ratios of change in increase in oxygen (O 2 ) uptake relative to increase in work rate (ΔVO 2 /ΔWR) across anaerobic threshold (AT) and 1 mm ST depression point (ST-dep), the time constants of VO 2 during recovery (T 1/2 VO 2 ), stress radio-isotope scintigraphy and coronary angiography. Patients were divided into CAD positive (CAD+) and CAD negative (CAD-) groups, based on coronary angiography. In CAD+, ΔVO 2 /ΔWR decreased above AT and ST-dep, in contrast to CAD- patients. The T 1/2 VO 2 in CAD+ (103.1±13.0 s) was greater than that of CAD- (76.5±8.7 s) and showed negative correlations to the ratios of ΔVO 2 /ΔWR across AT and ST-dep. These parameters improved in the patients who underwent coronary bypass surgery. Exercise and recovery VO 2 kinetics were slowed when myocardial ischemia was provoked by exercise. Measurement of exercise and recovery VO 2 kinetics improve the accuracy of the exercise electrocardiogram diagnosis of CAD. (author)

  2. Functional High-Intensity Circuit Training Improves Body Composition, Peak Oxygen Uptake, Strength, and Alters Certain Dimensions of Quality of Life in Overweight Women.

    Science.gov (United States)

    Sperlich, Billy; Wallmann-Sperlich, Birgit; Zinner, Christoph; Von Stauffenberg, Valerie; Losert, Helena; Holmberg, Hans-Christer

    2017-01-01

    The effects of circuit-like functional high-intensity training (Circuit HIIT ) alone or in combination with high-volume low-intensity exercise (Circuit combined ) on selected cardio-respiratory and metabolic parameters, body composition, functional strength and the quality of life of overweight women were compared. In this single-center, two-armed randomized, controlled study, overweight women performed 9-weeks (3 sessions·wk -1 ) of either Circuit HIIT ( n = 11), or Circuit combined ( n = 8). Peak oxygen uptake and perception of physical pain were increased to a greater extent ( p body mass, body-mass-index, waist-to-hip ratio, fat mass, and enhanced fat-free mass; decreased ratings of perceived exertion during submaximal treadmill running; improved the numbers of push-ups, burpees, one-legged squats, and 30-s skipping performed, as well as the height of counter-movement jumps; and improved physical and social functioning, role of physical limitations, vitality, role of emotional limitations, and mental health to a similar extent (all p training can be employed to improve body composition, selected variables of functional strength, and certain dimensions of quality of life in overweight women. However, Circuit HIIT improves peak oxygen uptake to a greater extent, but with more perception of pain, whereas Circuit combined results in better perception of general health.

  3. Peak oxygen uptake and left ventricular ejection fraction, but not depressive symptoms, are associated with cognitive impairment in patients with chronic heart failure

    Directory of Open Access Journals (Sweden)

    Steinberg G

    2011-12-01

    Full Text Available Gerrit Steinberg1,2*, Nicole Lossnitzer2*, Dieter Schellberg2, Thomas Mueller-Tasch2, Carsten Krueger3, Markus Haass4, Karl Heinz Ladwig5, Wolfgang Herzog2, Jana Juenger21University Hospital of Psychiatry, University of Bern, Bern, Switzerland; 2Department of Psychosomatic and General Internal Medicine, Medical Hospital, University of Heidelberg, Heidelberg, 3Department of Cardiology, Josefs Hospital, Heidelberg, 4Department of Cardiology, Theresien Hospital, Mannheim, 5Institute of Epidemiology, German Research Center for Environmental Health, Munich, Germany*both authors contributed equally to this paperBackground: The aim of the present study was to assess cognitive impairment in patients with chronic heart failure (CHF and its associations with depressive symptoms and somatic indicators of illness severity, which is a matter of controversy.Methods and results: Fifty-five patients with CHF (mean age 55.3 ± 7.8 years; 80% male; New York Heart Association functional class I–III underwent assessment with an expanded neuropsychological test battery (eg, memory, complex attention, mental flexibility, psychomotor speed to evaluate objective and subjective cognitive impairment. Depressive symptoms were assessed using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (SCID and a self-report inventory (Hospital Anxiety and Depression Scale [HADS]. A comprehensive clinical dataset, including left ventricular ejection fraction, peak oxygen uptake, and a 6-minute walk test, was obtained for all patients. Neuropsychological functioning revealed impairment in 56% of patients in at least one measure of our neuropsychological test battery. However, the Mini Mental State Examination (MMSE could only detect cognitive impairment in 1.8% of all patients, 24% had HADS scores indicating depressive symptoms, and 11.1% met SCID criteria for a depressive disorder. No significant association was found

  4. Evaluation of Optimum Moisture Content for Composting of Beef Manure and Bedding Material Mixtures Using Oxygen Uptake Measurement

    OpenAIRE

    Eunjong Kim; Dong-Hyun Lee; Seunggun Won; Heekwon Ahn

    2016-01-01

    Moisture content influences physiological characteristics of microbes and physical structure of solid matrices during composting of animal manure. If moisture content is maintained at a proper level, aerobic microorganisms show more active oxygen consumption during composting due to increased microbial activity. In this study, optimum moisture levels for composting of two bedding materials (sawdust, rice hull) and two different mixtures of bedding and beef manure (BS, Beef cattle manure+sawdu...

  5. Effects of modified multistage field test on performance and physiological responses in wheelchair basketball players.

    Science.gov (United States)

    Weissland, Thierry; Faupin, Arnaud; Borel, Benoit; Berthoin, Serge; Leprêtre, Pierre-Marie

    2015-01-01

    A bioenergetical analysis of manoeuvrability and agility performance for wheelchair players is inexistent. It was aimed at comparing the physiological responses and performance obtained from the octagon multistage field test (MFT) and the modified condition in "8 form" (MFT-8). Sixteen trained wheelchair basketball players performed both tests in randomized condition. The levels performed (end-test score), peak values of oxygen uptake (VO2peak), minute ventilation (VEpeak), heart rate (HRpeak), peak and relative blood lactate (Δ[Lact(-)] = peak--rest values), and the perceived rating exertion (RPE) were measured. MFT-8 induced higher VO2peak and VEpeak values compared to MFT (VO2peak: 2.5 ± 0.6 versus 2.3 ± 0.6 L · min(-1) and VEpeak: 96.3 ± 29.1 versus 86.6 ± 23.4 L · min(-1); P < 0.05) with no difference in other parameters. Significant relations between VEpeak and end-test score were correlated for both field tests (P < 0.05). At exhaustion, MFT attained incompletely VO2peak and VEpeak. Among experienced wheelchair players, MFT-8 had no effect on test performance but generates higher physiological responses than MFT. It could be explained by demands of wheelchair skills occurring in 8 form during the modified condition.

  6. Arm cranking versus wheelchair propulsion for testing aerobic fitness in children with spina bifida who are wheelchair dependent.

    Science.gov (United States)

    Bloemen, Manon A T; de Groot, Janke F; Backx, Frank J G; Westerveld, Rosalyne A; Takken, Tim

    2015-05-01

    To determine the best test performance and feasibility using a Graded Arm Cranking Test vs a Graded Wheelchair Propulsion Test in young people with spina bifida who use a wheelchair, and to determine the reliability of the best test. Validity and reliability study. Young people with spina bifida who use a wheelchair. Physiological responses were measured during a Graded Arm Cranking Test and a Graded Wheelchair Propulsion Test using a heart rate monitor and calibrated mobile gas analysis system (Cortex Metamax). For validity, peak oxygen uptake (VO2peak) and peak heart rate (HRpeak) were compared using paired t-tests. For reliability, the intra-class correlation coefficients, standard error of measurement, and standard detectable change were calculated. VO2peak and HRpeak were higher during wheelchair propulsion compared with arm cranking (23.1 vs 19.5 ml/kg/min, p = 0.11; 165 vs 150 beats/min, p propulsion showed high intra-class correlation coefficients (ICCs) for both VO2peak (ICC = 0.93) and HRpeak (ICC = 0.90). This pilot study shows higher HRpeak and a tendency to higher VO2peak in young people with spina bifida who are using a wheelchair when tested during wheelchair propulsion compared with arm cranking. Wheelchair propulsion showed good reliability. We recommend performing a wheelchair propulsion test for aerobic fitness testing in this population.

  7. Myosin heavy chain composition in the vastus lateralis muscle in relation to oxygen uptake and heart rate during cycling in humans.

    Science.gov (United States)

    Majerczak, J; Nieckarz, Z; Karasinski, J; Zoladz, J A

    2014-04-01

    In this study we examined the relationship between fast myosin heavy chain (MyHC2) content in the vastus lateralis and the rate of oxygen uptake (VO2) and heart rate (HR) increase during an incremental exercise in 38, young, healthy men. Prior to the exercise test, muscle biopsies were taken in order to evaluate the MyHC composition. It was found that during cycling performed below the lactate threshold (LT), a positive relationship between MyHC2 and the intercept of the oxygen uptake and power output (VO2-PO) relationship existed (r=0.49, P=0.002), despite no correlation between MyHC2 and the slope value of the VO2-PO relationship (r= -0.18, P=0.29). During cycling performed above the LT, MyHC2 correlated positively with the magnitude of the nonlinearity in the VO2-PO relationship; i.e. with the accumulated VO2'excess' (r=0.44, P=0.006) and peak VO2'excess' (r=0.44, P=0.006), as well as with the slope of the HR-PO relationship (r=0.49, P=0.002). We have concluded that a greater MyHC2 content in the vastus lateralis is accompanied by a higher oxygen cost of cycling during exercise performed below the LT. This seems to be related to the higher energy cost of the non-cross-bridge activities in the muscles possessing a greater proportion of MyHC2 content. In the case of heavy-intensity exercise, a higher MyHC2 content in the vastus lateralis is accompanied by greater non-linearity in the VO2-PO relationship, as well as a steeper increase in HR in the function of an increase of PO. This relationship can be explained by greater disturbances in metabolic stability in type II muscle fibres during exercise, resulting in a decrease of muscle mechanical efficiency and greater increase of heart rate at a given power output. Therefore, MyHC composition has an impact on the oxygen cost of cycling both below and above the LT.

  8. Peak oxygen uptake and left ventricular ejection fraction, but not depressive symptoms, are associated with cognitive impairment in patients with chronic heart failure.

    Science.gov (United States)

    Steinberg, Gerrit; Lossnitzer, Nicole; Schellberg, Dieter; Mueller-Tasch, Thomas; Krueger, Carsten; Haass, Markus; Ladwig, Karl Heinz; Herzog, Wolfgang; Juenger, Jana

    2011-01-01

    The aim of the present study was to assess cognitive impairment in patients with chronic heart failure (CHF) and its associations with depressive symptoms and somatic indicators of illness severity, which is a matter of controversy. Fifty-five patients with CHF (mean age 55.3 ± 7.8 years; 80% male; New York Heart Association functional class I-III) underwent assessment with an expanded neuropsychological test battery (eg, memory, complex attention, mental flexibility, psychomotor speed) to evaluate objective and subjective cognitive impairment. Depressive symptoms were assessed using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (SCID) and a self-report inventory (Hospital Anxiety and Depression Scale [HADS]). A comprehensive clinical dataset, including left ventricular ejection fraction, peak oxygen uptake, and a 6-minute walk test, was obtained for all patients. Neuropsychological functioning revealed impairment in 56% of patients in at least one measure of our neuropsychological test battery. However, the Mini Mental State Examination (MMSE) could only detect cognitive impairment in 1.8% of all patients, 24% had HADS scores indicating depressive symptoms, and 11.1% met SCID criteria for a depressive disorder. No significant association was found between depressive symptoms and cognitive impairment. Left ventricular ejection fraction was related to subjective cognitive impairment, and peak oxygen uptake was related to objective cognitive impairment. Cognitive functioning was substantially reduced in patients with CHF and should therefore be diagnosed and treated in routine clinical practice. Caution is advised when the MMSE is used to identify cognitive impairment in patients with CHF.

  9. Effects of hyperoxia on 18F-fluoro-misonidazole brain uptake and tissue oxygen tension following middle cerebral artery occlusion in rodents: Pilot studies.

    Directory of Open Access Journals (Sweden)

    Tim D Fryer

    Full Text Available Mapping brain hypoxia is a major goal for stroke diagnosis, pathophysiology and treatment monitoring. 18F-fluoro-misonidazole (FMISO positron emission tomography (PET is the gold standard hypoxia imaging method. Normobaric hyperoxia (NBO is a promising therapy in acute stroke. In this pilot study, we tested the straightforward hypothesis that NBO would markedly reduce FMISO uptake in ischemic brain in Wistar and spontaneously hypertensive rats (SHRs, two rat strains with distinct vulnerability to brain ischemia, mimicking clinical heterogeneity.Thirteen adult male rats were randomized to distal middle cerebral artery occlusion under either 30% O2 or 100% O2. FMISO was administered intravenously and PET data acquired dynamically for 3hrs, after which magnetic resonance imaging (MRI and tetrazolium chloride (TTC staining were carried out to map the ischemic lesion. Both FMISO tissue uptake at 2-3hrs and FMISO kinetic rate constants, determined based on previously published kinetic modelling, were obtained for the hypoxic area. In a separate group (n = 9, tissue oxygen partial pressure (PtO2 was measured in the ischemic tissue during both control and NBO conditions.As expected, the FMISO PET, MRI and TTC lesion volumes were much larger in SHRs than Wistar rats in both the control and NBO conditions. NBO did not appear to substantially reduce FMISO lesion size, nor affect the FMISO kinetic rate constants in either strain. Likewise, MRI and TTC lesion volumes were unaffected. The parallel study showed the expected increases in ischemic cortex PtO2 under NBO, although these were small in some SHRs with very low baseline PtO2.Despite small samples, the apparent lack of marked effects of NBO on FMISO uptake suggests that in permanent ischemia the cellular mechanisms underlying FMISO trapping in hypoxic cells may be disjointed from PtO2. Better understanding of FMISO trapping processes will be important for future applications of FMISO imaging.

  10. Changes in cardiac activity, oxygen uptake and perfusion indices in Carcinus maenas (L. ) exposed to crude oil and dispersant

    Energy Technology Data Exchange (ETDEWEB)

    Depledge, M.H.

    1984-01-01

    Cardiac activity and oxygen consumption increased when C. maenas were exposed to a 20% solution of the water-soluble fraction of Fortes crude oil, a 10% solution of the dispersant BP1100WD or a combination of both. Normal feeding behaviour was disrupted. Perfusion indices (Q/VO2) decreased as locomotor activity increased following exposure to crude oil. However, exposure to dispersant or dispersant + crude oil resulted in elevation of perfusion index despite crabs becoming active. All test animals survived for at least 6 weeks following exposure to the pollutants. The acute, sublethal effects of dispersant and dispersant + crude oil were more severe than the effects of crude oil alone.

  11. Comparison of the Danish step test and the watt-max test for estimation of maximal oxygen uptake

    DEFF Research Database (Denmark)

    Aadahl, Mette; Zacho, Morten; Linneberg, Allan René

    2013-01-01

    . Altogether, 795 eligible participants (response rate 35.8%) performed the watt max and the Danish step test. Correlation and agreement between the two VO(2max) test results was explored by Pearson's rho, Bland-Altman plots, Kappa(w), and gamma coefficients.Results: The correlation between VO(2max) (ml......Introduction: There is a need for simple and feasible methods for estimation of cardiorespiratory fitness (CRF) in large study populations, as existing methods for valid estimation of maximal oxygen consumption are generally time consuming and relatively expensive to administer. The Danish step...

  12. Asymmetry of quadriceps muscle oxygenation during elite short-track speed skating.

    Science.gov (United States)

    Hesford, Catherine Mary; Laing, Stewart J; Cardinale, Marco; Cooper, Chris E

    2012-03-01

    It has been suggested that, because of the low sitting position in short-track speed skating, muscle blood flow is restricted, leading to decreases in tissue oxygenation. Therefore, wearable wireless-enabled near-infrared spectroscopy (NIRS) technology was used to monitor changes in quadriceps muscle blood volume and oxygenation during a 500-m race simulation in short-track speed skaters. Six elite skaters, all of Olympic standard (age = 23 ± 1.8 yr, height = 1.8 ± 0.1 m, mass = 80.1 ± 5.7 kg, midthigh skinfold thickness = 7 ± 2 mm), were studied. Subjects completed a 500-m race simulation time trial (TT). Whole-body oxygen consumption was simultaneously measured with muscle oxygenation in right and left vastus lateralis as measured by NIRS. Mean time for race completion was 44.8 ± 0.4 s. VO2 peaked 20 s into the race. In contrast, muscle tissue oxygen saturation (TSI%) decreased and plateaued after 8 s. Linear regression analysis showed that right leg TSI% remained constant throughout the rest of the TT (slope value = 0.01), whereas left leg TSI% increased steadily (slope value = 0.16), leading to a significant asymmetry (P skating has implications for training and performance.

  13. Relationship of bronchodilator response with oxygen pulse and ventilatory threshold in children with asthma: the effect of body composition and progressive aerobic activity in an environment with low humidity

    Directory of Open Access Journals (Sweden)

    Samera Puyan majd

    2015-11-01

    Full Text Available Background: Asthma is a leading cause of chronic illness in children, impacting heavily on their daily complications. The purpose of the present study was to relationship bronchodilator response (BDR with oxygen pulse (OP and ventilatory threshold (VT in asthma children with various body compositions during progressive aerobic activities. Material and Methods: 25 obese children (BMI>25 and %fat>30with asthma(10 subjects, and healthy children (15 subjects  and 25 lean children(BMI<20 and %fat<20 with asthma(13 subjects, and healthy children (7 subjects performed an exercise protocol in a constant temperature environment 2 ± 22 ° C and humidity (5 ± 35%. During exercise, the steady-state levels of cardio-respiratory parameters were measured using gas analyzer (K4B2. Results: The results showed that after a progressive aerobic activity, values peak oxygen consumption(vo2peak ​​, bronchodilator(BDR, oxygen pulse(OP and ventilatory threshold(VT  in lean and obese asthmatic children were lower than in healthy lean and obese children. In addition, lean children with asthma had lower VT and higher VO2peak , OP and BDR values​​, as compared obese asthmatic children. Between BDR and VT in lean and obese asthmatic children an inverse relationship between BDR and OP and a direct link to asthma in obese children and obese asthmatic children, there was a negative relationship non-significant. Conclusion: Compared with lean children, asthma, obesity as an additional load will affect lung function and increase the pressure on childhood asthma. Therefore, we can accept that obesity may limit performance of exercise in childhood asthma.

  14. Effect of pedal rate on primary and slow-component oxygen uptake responses during heavy-cycle exercise.

    Science.gov (United States)

    Pringle, Jamie S M; Doust, Jonathan H; Carter, Helen; Tolfrey, Keith; Jones, Andrew M

    2003-04-01

    We hypothesized that a higher pedal rate (assumed to result in a greater proportional contribution of type II motor units) would be associated with an increased amplitude of the O(2) uptake (Vo(2)) slow component during heavy-cycle exercise. Ten subjects (mean +/- SD, age 26 +/- 4 yr, body mass 71.5 +/- 7.9 kg) completed a series of square-wave transitions to heavy exercise at pedal rates of 35, 75, and 115 rpm. The exercise power output was set at 50% of the difference between the pedal rate-specific ventilatory threshold and peak Vo(2), and the baseline power output was adjusted to account for differences in the O(2) cost of unloaded pedaling. The gain of the Vo(2) primary component was significantly higher at 35 rpm compared with 75 and 115 rpm (mean +/- SE, 10.6 +/- 0.3, 9.5 +/- 0.2, and 8.9 +/- 0.4 ml. min(-1). W(-1), respectively; P exercise at the same relative intensity, presumably by altering motor unit recruitment patterns.

  15. Partial neuromuscular blockade in humans enhances muscle blood flow during exercise independently of muscle oxygen uptake and acetylcholine receptor blockade

    DEFF Research Database (Denmark)

    Hellsten, Ylva; Krustrup, Peter; Iaia, F Marcello

    2009-01-01

    This study examined the role of acetylcholine for skeletal muscle blood flow during exercise by use of the competitive neuromuscular blocking agent cisatracurium in combination with the acetylcholine receptor blocker glycopyrrone. Nine healthy male subjects performed a 10-min bout of one-legged k......This study examined the role of acetylcholine for skeletal muscle blood flow during exercise by use of the competitive neuromuscular blocking agent cisatracurium in combination with the acetylcholine receptor blocker glycopyrrone. Nine healthy male subjects performed a 10-min bout of one...... conductance during exercise, events that are not associated with either acetylcholine or an increased oxygen demand. The results do not support an essential role for acetylcholine, released form the neuromuscular junction, in exercise hyperaemia or for the enhanced blood flow during neuromuscular blockade....... The enhanced exercise hyperemia during partial neuromuscular blockade may be related to a greater recruitment of fast-twitch muscle fibres. Key words: blood flow, neuromuscular blockade, exercise, skeletal muscle....

  16. Oxygen-Dependent Transcriptional Regulator Hap1p Limits Glucose Uptake by Repressing the Expression of the Major Glucose Transporter Gene RAG1 in Kluyveromyces lactis▿

    Science.gov (United States)

    Bao, Wei-Guo; Guiard, Bernard; Fang, Zi-An; Donnini, Claudia; Gervais, Michel; Passos, Flavia M. Lopes; Ferrero, Iliana; Fukuhara, Hiroshi; Bolotin-Fukuhara, Monique

    2008-01-01

    The HAP1 (CYP1) gene product of Saccharomyces cerevisiae is known to regulate the transcription of many genes in response to oxygen availability. This response varies according to yeast species, probably reflecting the specific nature of their oxidative metabolism. It is suspected that a difference in the interaction of Hap1p with its target genes may explain some of the species-related variation in oxygen responses. As opposed to the fermentative S. cerevisiae, Kluyveromyces lactis is an aerobic yeast species which shows different oxygen responses. We examined the role of the HAP1-equivalent gene (KlHAP1) in K. lactis. KlHap1p showed a number of sequence features and some gene targets (such as KlCYC1) in common with its S. cerevisiae counterpart, and KlHAP1 was capable of complementing the hap1 mutation. However, the KlHAP1 disruptant showed temperature-sensitive growth on glucose, especially at low glucose concentrations. At normal temperature, 28°C, the mutant grew well, the colony size being even greater than that of the wild type. The most striking observation was that KlHap1p repressed the expression of the major glucose transporter gene RAG1 and reduced the glucose uptake rate. This suggested an involvement of KlHap1p in the regulation of glycolytic flux through the glucose transport system. The ΔKlhap1 mutant showed an increased ability to produce ethanol during aerobic growth, indicating a possible transformation of its physiological property to Crabtree positivity or partial Crabtree positivity. Dual roles of KlHap1p in activating respiration and repressing fermentation may be seen as a basis of the Crabtree-negative physiology of K. lactis. PMID:18806211

  17. A hybrid multibreath wash-in wash-out lung function quantification scheme in human subjects using hyperpolarized 3 He MRI for simultaneous assessment of specific ventilation, alveolar oxygen tension, oxygen uptake, and air trapping.

    Science.gov (United States)

    Hamedani, Hooman; Kadlecek, Stephen; Xin, Yi; Siddiqui, Sarmad; Gatens, Heather; Naji, Joseph; Ishii, Masaru; Cereda, Maurizio; Rossman, Milton; Rizi, Rahim

    2017-08-01

    To present a method for simultaneous acquisition of alveolar oxygen tension (P A O 2 ), specific ventilation (SV), and apparent diffusion coefficient (ADC) of hyperpolarized (HP) gas in the human lung, allowing reinterpretation of the P A O 2 and SV maps to produce a map of oxygen uptake (R). An imaging scheme was designed with a series of identical normoxic HP gas wash-in breaths to measure ADC, SV, P A O 2 , and R in less than 2 min. Signal dynamics were fit to an iterative recursive model that regionally solved for these parameters. This measurement was successfully performed in 12 subjects classified in three healthy, smoker, and chronic obstructive pulmonary disease (COPD) cohorts. The overall whole lung ADC, SV, P A O 2 , and R in healthy, smoker, and COPD subjects was 0.20 ± 0.03 cm 2 /s, 0.39 ± 0.06,113 ± 2 Torr, and 1.55 ± 0.35 Torr/s, respectively, in healthy subjects; 0.21 ± 0.03 cm 2 /s, 0.33 ± 0.06, 115.9 ± 4 Torr, and 0.97 ± 0.2 Torr/s, respectively, in smokers; and 0.25 ± 0.06 cm 2 /s, 0.23 ± 0.08, 114.8 ± 6.0Torr, and 0.94 ± 0.12 Torr/s, respectively, in subjects with COPD. Hetrogeneity of SV, P A O 2 , and R were indicators of both smoking-related changes and disease, and the severity of the disease correlated with the degree of this heterogeneity. Subjects with symptoms showed reduced oxygen uptake and specific ventilation. High-resolution, nearly coregistered and quantitative measures of lung function and structure were obtained with less than 1 L of HP gas. This hybrid multibreath technique produced measures of lung function that revealed clear differences among the cohorts and subjects and were confirmed by correlations with global lung measurements. Magn Reson Med 78:611-624, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  18. A preliminary study

    DEFF Research Database (Denmark)

    Rostgaard Andersen, Thomas; Schmidt, Jakob Friis; Thomassen, Martin

    2014-01-01

    The effects of regular football training on glycemic control, body composition, and peak oxygen uptake (VO2 peak) were investigated in men with type 2 diabetes mellitus (T2DM). Twenty-one middle-aged men (49.8 ± 1.7 years ± SEM) with T2DM were divided into a football training group (FG; n = 12) a...

  19. Photodynamic Inactivation of Candida albicans with Imidazoacridinones: Influence of Irradiance, Photosensitizer Uptake and Reactive Oxygen Species Generation.

    Directory of Open Access Journals (Sweden)

    Aleksandra Taraszkiewicz

    Full Text Available The increasing applicability of antifungal treatments, the limited range of available drug classes and the emergence of drug resistance in Candida spp. suggest the need for new treatment options. To explore the applicability of C. albicans photoinactivation, we examined nine structurally different imidazoacridinone derivatives as photosensitizing agents. The most effective derivatives showed a >10(4-fold reduction of viable cell numbers. The fungicidal action of the three most active compounds was compared at different radiant powers (3.5 to 63 mW/cm2, and this analysis indicated that 7 mW/cm2 was the most efficient. The intracellular accumulation of these compounds in fungal cells correlated with the fungicidal activity of all 9 derivatives. The lack of effect of verapamil, an inhibitor targeting Candida ABC efflux pumps, suggests that these imidazoacridinones are not substrates for ABC transporters. Thus, unlike azoles, a major class of antifungals used against Candida, ABC transporter-mediated resistance is unlikely. Electron paramagnetic resonance (EPR-spin trapping data suggested that the fungicidal light-induced action of these derivatives might depend on the production of superoxide anion. The highest generation rate of superoxide anion was observed for 1330H, 1610H, and 1611. Singlet oxygen production was also detected upon the irradiation of imidazoacridinone derivatives with UV laser light, with a low to moderate yield, depending on the type of compound. Thus, imidazoacridinone derivatives examined in the present study might act via mixed type I/type II photodynamic mechanism. The presented data indicate lack of direct correlation between the structures of studied imidazoacridinones, cell killing ability, and ROS production. However, we showed for the first time that for imidazoacridinones not only intracellular accumulation is necessary prerequisite of lethal photosensitization of C. albicans, but also localization within particular

  20. Increased Tumor Oxygenation and Drug Uptake During Anti-Angiogenic Weekly Low Dose Cyclophosphamide Enhances the Anti-Tumor Effect of Weekly Tirapazamine

    Science.gov (United States)

    Doloff, J.C.; Khan, N.; Ma, J.; Demidenko, E.; Swartz, H.M.; Jounaidi, Y.

    2010-01-01

    Metronomic cyclophosphamide treatment is associated with anti-angiogenic activity and is anticipated to generate exploitable hypoxia using hypoxia-activated prodrugs. Weekly administration of tirapazamine (TPZ; 5 mg/kg body weight i.p.) failed to inhibit the growth of 9L gliosarcoma tumors grown s.c. in scid mice. However, the anti-tumor effect of weekly cyclophosphamide (CPA) treatment (140 mg/kg BW i.p.) was substantially enhanced by weekly TPZ administration. An extended tumor free period and increased frequency of tumor eradication without overt toxicity were observed when TPZ was given 3, 4 or 5 days after each weekly CPA treatment. Following the 2nd CPA injection, Electron Paramagnetic Resonance (EPR) Oximetry indicated significant increases in tumor pO2, starting at 48 hr, which further increased after the 3rd CPA injection. pO2 levels were, however, stable in growing untreated tumors. A strong negative correlation (−0.81) between tumor pO2 and tumor volume during 21 days of weekly CPA chemotherapy was observed, indicating increasing tumor pO2 with decreasing tumor volume. Furthermore, CPA treatment resulted in increased tumor uptake of activated CPA. CPA induced increases in VEGF RNA, which reached a maximum on day 1, and in PLGF RNA which was sustained throughout the treatment, while anti-angiogenic host thrombospondin-1 increased dramatically through day 7 post-CPA treatment. Weekly cyclophosphamide treatment was anticipated to generate exploitable hypoxia. However, our findings suggest that weekly CPA treatment induces a functional improvement of tumor vasculature, which is characterized by increased tumor oxygenation and drug uptake in tumors, thus counter-intuitively, benefiting intratumoral activation of TPZ and perhaps other bioreductive drugs. PMID:19754361

  1. Assessment of peak oxygen uptake during handcycling: Test-retest reliability and comparison of a ramp-incremented and perceptually-regulated exercise test.

    Science.gov (United States)

    Hutchinson, Michael J; Paulson, Thomas A W; Eston, Roger; Goosey-Tolfrey, Victoria L

    2017-01-01

    To examine the reliability of a perceptually-regulated maximal exercise test (PRETmax) to measure peak oxygen uptake ([Formula: see text]) during handcycle exercise and to compare peak responses to those derived from a ramp-incremented protocol (RAMP). Twenty recreationally active individuals (14 male, 6 female) completed four trials across a 2-week period, using a randomised, counterbalanced design. Participants completed two RAMP protocols (20 W·min-1) in week 1, followed by two PRETmax in week 2, or vice versa. The PRETmax comprised five, 2-min stages clamped at Ratings of Perceived Exertion (RPE) 11, 13, 15, 17 and 20. Participants changed power output (PO) as often as required to maintain target RPE. Gas exchange variables (oxygen uptake, carbon dioxide production, minute ventilation), heart rate (HR) and PO were collected throughout. Differentiated RPE were collected at the end of each stage throughout trials. For relative [Formula: see text], coefficient of variation (CV) was equal to 4.1% and 4.8%, with ICC(3,1) of 0.92 and 0.85 for repeated measures from PRETmax and RAMP, respectively. Measurement error was 0.15 L·min-1 and 2.11 ml·kg-1·min-1 in PRETmax and 0.16 L·min-1 and 2.29 ml·kg-1·min-1 during RAMP for determining absolute and relative [Formula: see text], respectively. The difference in [Formula: see text] between PRETmax and RAMP was tending towards statistical significance (26.2 ± 5.1 versus 24.3 ± 4.0 ml·kg-1·min-1, P = 0.055). The 95% LoA were -1.9 ± 4.1 (-9.9 to 6.2) ml·kg-1·min-1. The PRETmax can be used as a reliable test to measure [Formula: see text] during handcycle exercise in recreationally active participants. Whilst PRETmax tended towards significantly greater [Formula: see text] values than RAMP, the difference is smaller than measurement error of determining [Formula: see text] from PRETmax and RAMP.

  2. Skeletal muscle-specific expression of PGC-1α-b, an exercise-responsive isoform, increases exercise capacity and peak oxygen uptake.

    Directory of Open Access Journals (Sweden)

    Miki Tadaishi

    Full Text Available Maximal oxygen uptake (VO(2max predicts mortality and is associated with endurance performance. Trained subjects have a high VO(2max due to a high cardiac output and high metabolic capacity of skeletal muscles. Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α, a nuclear receptor coactivator, promotes mitochondrial biogenesis, a fiber-type switch to oxidative fibers, and angiogenesis in skeletal muscle. Because exercise training increases PGC-1α in skeletal muscle, PGC-1α-mediated changes may contribute to the improvement of exercise capacity and VO(2max. There are three isoforms of PGC-1α mRNA. PGC-1α-b protein, whose amino terminus is different from PGC-1α-a protein, is a predominant PGC-1α isoform in response to exercise. We investigated whether alterations of skeletal muscle metabolism by overexpression of PGC-1α-b in skeletal muscle, but not heart, would increase VO(2max and exercise capacity.Transgenic mice showed overexpression of PGC-1α-b protein in skeletal muscle but not in heart. Overexpression of PGC-1α-b promoted mitochondrial biogenesis 4-fold, increased the expression of fatty acid transporters, enhanced angiogenesis in skeletal muscle 1.4 to 2.7-fold, and promoted exercise capacity (expressed by maximum speed by 35% and peak oxygen uptake by 20%. Across a broad range of either the absolute exercise intensity, or the same relative exercise intensities, lipid oxidation was always higher in the transgenic mice than wild-type littermates, suggesting that lipid is the predominant fuel source for exercise in the transgenic mice. However, muscle glycogen usage during exercise was absent in the transgenic mice.Increased mitochondrial biogenesis, capillaries, and fatty acid transporters in skeletal muscles may contribute to improved exercise capacity via an increase in fatty acid utilization. Increases in PGC-1α-b protein or function might be a useful strategy for sedentary subjects to perform exercise

  3. Dopamine in human follicular fluid is associated with cellular uptake and metabolism-dependent generation of reactive oxygen species in granulosa cells: implications for physiology and pathology.

    Science.gov (United States)

    Saller, S; Kunz, L; Berg, D; Berg, U; Lara, H; Urra, J; Hecht, S; Pavlik, R; Thaler, C J; Mayerhofer, A

    2014-03-01

    Is the neurotransmitter dopamine (DA) in the human ovary involved in the generation of reactive oxygen species (ROS)? Human ovarian follicular fluid contains DA, which causes the generation of ROS in cultured human granulosa cells (GCs), and alterations of DA levels in follicular fluid and DA uptake/metabolism in GCs in patients with polycystic ovary syndrome (PCOS) are linked to increased levels of ROS. DA is an important neurotransmitter in the brain, and the metabolism of DA results in the generation of ROS. DA was detected in human ovarian homogenates, but whether it is present in follicular fluid and plays a role in the follicle is not known. We used human follicular fluid from patients undergoing in vitro fertilization (IVF), GCs from patients with or without PCOS and also employed mathematical modeling to investigate the presence of DA and its effects on ROS. DA in follicular fluid and GCs was determined by enzyme-linked immunosorbent assay. GC viability, apoptosis and generation of ROS were monitored in GCs upon addition of DA. Inhibitors of DA uptake and metabolism, an antioxidant and DA receptor agonists, were used to study cellular uptake and the mechanism of DA-induced ROS generation. Human GCs were examined for the presence and abundance of transcripts of the DA transporter (DAT; SLC6A3), the DA-metabolizing enzymes monoamine oxidases A/B (MAO-A/B) and catechol-O-methyltransferase and the vesicular monoamine transporter. A computational model was developed to describe and predict DA-induced ROS generation in human GCs. We found DA in follicular fluid of ovulatory follicles of the human ovary and in GCs. DAT and MAO-A/B, which are expressed by GCs, are prerequisites for a DA receptor-independent generation of ROS in GCs. Blockers of DAT and MAO-A/B, as well as an antioxidant, prevented the generation of ROS (P human follicular compartment, functions of DA could only be studied in IVF-derived GCs, which can be viewed as a cellular model for the

  4. Interactive effect of body posture on exercise-induced atrial natriuretic peptide release.

    Science.gov (United States)

    Ray, C A; Delp, M D; Hartle, D K

    1990-05-01

    The purpose of this investigation was to test the hypothesis that supine exercise elicits a greater atrial natriuretic peptide (ANP) response than upright exercise because of higher atrial filling pressure attained in the supine posture. Plasma ANP concentration ([ANP]) was measured during continuous graded supine and upright exercise in eight healthy men at rest after 4 min of cycling exercise at 31, 51, and 79% of posture-specific peak oxygen uptake (VO2 peak), after 2 min of cycling at posture-specific VO2 peak, and 5 and 15 min postexercise. [ANP] was significantly increased (P less than 0.05) above rest by 64, 140, and 228% during supine cycling at 51 and 79% and VO2 peak, respectively. During upright cycling, [ANP] was significantly increased (P less than 0.05) at 79% (60%) and VO2 peak (125%). After 15 min of postexercise rest, [ANP] remained elevated (P less than 0.05) only in the supine subjects. [ANP] was 63, 79, and 75% higher (P less than 0.05) in the supine than in the upright position during cycling at 51 and 79% and VO2 peak. Systolic, diastolic, and mean blood pressures were not significantly (P greater than 0.05) different between positions in all measurement periods. Heart rates were lower (P less than 0.05) in the supine position compared with the upright position. In conclusion, these results suggest that supine exercise elicits greater ANP release independent of blood pressure and heart rate but presumably caused by greater venous return, central blood volume, and concomitant atrial filling pressure and stretch.

  5. Cardiopulmonary fitness correlates with regional cerebral grey matter perfusion and density in men with coronary artery disease.

    Directory of Open Access Journals (Sweden)

    Bradley J MacIntosh

    Full Text Available Physical activity is associated with positive effects on the brain but there is a paucity of clinical neuroimaging data in patients with coronary artery disease (CAD, a cardiovascular condition associated with grey matter loss. The purpose of this study was to determine which brain regions are impacted by cardiopulmonary fitness and with the change in fitness after 6 months of exercise-based cardiac rehabilitation.CAD patients underwent magnetic resonance imaging at baseline, and peak volume of oxygen uptake during exercise testing (VO2Peak was measured at baseline and after 6 months of training. T1-weighted structural images were used to perform grey matter (GM voxel-based morphometry (VBM. Pseudo-continuous arterial spin labeling (pcASL was used to produce cerebral blood flow (CBF images. VBM and CBF data were tested voxel-wise using VO2Peak and age as explanatory variables.In 30 men with CAD (mean age 65±7 years, VBM and CBF identified 7 and 5 respective regions positively associated with baseline VO2Peak. These included the pre- and post-central, paracingulate, caudate, hippocampal regions and converging findings in the putamen. VO2Peak increased by 20% at follow-up in 29 patients (t = 9.6, df = 28, p<0.0001. Baseline CBF in the left post-central gyrus and baseline GM density in the right putamen predicted greater change in VO2Peak.Perfusion and GM density were associated with fitness at baseline and with greater fitness gains with exercise. This study identifies new neurobiological correlates of fitness and demonstrates the utility of multi-modal MRI to evaluate the effects of exercise in CAD patients.

  6. Response of the oxygen uptake efficiency slope to orthotopic heart transplantation: lack of correlation with changes in central hemodynamic parameters and resting lung function.

    Science.gov (United States)

    Van Laethem, Christophe; Goethals, Marc; Verstreken, Sofie; Walravens, Maarten; Wellens, Francis; De Proft, Margot; Bartunek, Jozef; Vanderheyden, Marc

    2007-09-01

    Recently, a new linear measure of ventilatory response to exercise, the oxygen uptake efficiency slope (OUES), was proposed in the evaluation of heart failure patients. No data are available on the response of the OUES after orthotopic heart transplantation (HTx). Thirty patients who underwent HTx between 1999 and 2003 were included in the study. Data from maximal cardiopulmonary exercise test, resting pulmonary function and hemodynamic assessment were collected before the transplant at time of screening and 1 year after HTx. During the first year after HTx, OUES and normalized OUES for body weight (OUES/kg) increased significantly from 15.6 +/- 4.9 to 19.7 +/- 4.8 (p volumes or capacities and measures of central hemodynamic function after HTx. OUES improved significantly after HTx, but, similar to other exercise parameters, remained considerably impaired. The changes in OUES were highly correlated with the improvements in other exercise variables, but did not correlate with marked improvements in central hemodynamics or resting lung function.

  7. Maximum oxygen uptake and objectively measured physical activity in Danish children 6-7 years of age: the Copenhagen school child intervention study

    DEFF Research Database (Denmark)

    Eiberg, Stig; Hasselstrøm, Henriette; Grønfeldt, Vivian

    2005-01-01

    Objectives: To provide normative data on maximum oxygen uptake (V·O2MAX) and physical activity in children 6-7 years of age and analyse the association between these variables. Methods: VO2MAX was measured in 366 boys (mean (SD) 6.8 (0.4) years of age) and 332 girls (6.7 (0.4) years of age) from.......5 (6.0) v 44.8 (5.6) ml/kg/min (+8%); pgirls. The difference in VO2MAX between boys and girls decreased to +2% when expressed relative to lean body mass (LBM). Absolute VO2MAX was related to LBM, body mass, and stature (all pBoys were more physically active than girls (mean counts...... +9.4%, pboys and girls with the same VO2MAX were compared, boys were more active. The difference in physical activity between the sexes was higher when sustained activity of higher intensity was compared. Conclusions: VO2MAX is higher in boys than girls (+11%), even when...

  8. Oxygen uptake during peak graded exercise and single-stage fatigue tests of wheelchair propulsion in manual wheelchair users and the able-bodied.

    Science.gov (United States)

    Keyser, R E; Rodgers, M M; Gardner, E R; Russell, P J

    1999-10-01

    To determine if a single-stage, submaximal fatigue test on a wheelchair ergometer would result in higher than expected energy expenditure. An experimental survey design contrasting physiologic responses during peak graded exercise tests and fatigue tests. A rehabilitation science laboratory that included a prototypical wheelchair ergometer, open-circuit spirometry system, and heart rate monitor. Nine able-bodied non-wheelchair users (the NWC group: 6 men and 3 women, mean +/- SD age 30 +/- 7yrs) and 15 manual wheelchair users (the WC group: 12 men and 3 women, age 40 +/- 9yrs, time in wheelchair 16 +/- 9yrs). No subject had any disease, medication regimen, or upper body neurologic, orthopedic, or other condition that would limit wheelchair exercise. Peak oxygen uptake (VO2) for graded exercise testing and during fatigue testing, using a power output corresponding to 75% peak aerobic capacity on graded exercise test. In the WC group, VO2 at 6 minutes of fatigue testing was not significantly different from peak VO2. In the NWC group, VO2 was similar to the expected level throughout fatigue testing. Energy expenditure was higher than expected in the WC group but not in the NWC group. Fatigue testing may provide a useful evaluation of cardiorespiratory status in manual wheelchair users.

  9. Effects of prior short multiple-sprint exercises with different intersprint recoveries on the slow component of oxygen uptake during high-intensity exercise.

    Science.gov (United States)

    Lanzi, Stefano; Borrani, Fabio; Wolf, Martin; Gojanovic, Boris; Malatesta, Davide

    2012-12-01

    This study compares the effects of two short multiple-sprint exercise (MSE) (6 × 6 s) sessions with two different recovery durations (30 s or 180 s) on the slow component of oxygen uptake ([Formula: see text]O(2)) during subsequent high-intensity exercise. Ten male subjects performed a 6-min cycling test at 50% of the difference between the gas exchange threshold and [Formula: see text]O(2peak) (Δ50). Then, the subjects performed two MSEs of 6 × 6 s separated by two intersprint recoveries of 30 s (MSE(30)) and 180 s (MSE(180)), followed 10 min later by the Δ50 (Δ50(30) and Δ50(180), respectively). Electromyography (EMG) activities of the vastus medialis and lateralis were measured throughout each exercise bout. During MSE(30), muscle activity (root mean square) increased significantly (p ≤ 0.04), with a significant leftward-shifted median frequency of the power density spectrum (MDF; p ≤ 0.01), whereas MDF was significantly rightward-shifted during MSE(180) (p = 0.02). The mean [Formula: see text]O(2) value was significantly higher in MSE(30) than in MSE(180) (p motor units recruitment profile (i.e., change in the type of muscle fibers recruited) and (or) an improved muscle O(2) delivery during subsequent exercise.

  10. Oxygen uptake and haemocyanin oxygen affinity

    African Journals Online (AJOL)

    1990-04-17

    Apr 17, 1990 ... reni showed that the two different gas exchange processes operating in water and in .... CaCl2 20 mmol rl; MgC~ 10 mmol rl; flow rate 7 ml h-I) at different pH values. ... on the moving canvas. In their behaviour on the treadmill,.

  11. High intensity interval training improves VO2peak, maximal lactate production, time trial and competition performance in 9-11 year old swimmers

    OpenAIRE

    Sperlich, Billy; Zinner, Christoph; Helleman, Ilka; Kjendlie, Per-Ludvik; Holmberg, H. C.; Mester, Joachim

    2010-01-01

    Open Access - This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the source is credited. Training volume in swimming is usually very high when compared to the relatively short competition time. High-intensity interval training (HIIT) has been demonstrated to improve performance in a relatively short training period. The main purpose of the present s...

  12. Low- and high-volume of intensive endurance training significantly improves maximal oxygen uptake after 10-weeks of training in healthy men.

    Directory of Open Access Journals (Sweden)

    Arnt Erik Tjønna

    Full Text Available Regular exercise training improves maximal oxygen uptake (VO2max, but the optimal intensity and volume necessary to obtain maximal benefit remains to be defined. A growing body of evidence suggests that exercise training with low-volume but high-intensity may be a time-efficient means to achieve health benefits. In the present study, we measured changes in VO2max and traditional cardiovascular risk factors after a 10 wk. training protocol that involved three weekly high-intensity interval sessions. One group followed a protocol which consisted of 4×4 min at 90% of maximal heart rate (HRmax interspersed with 3 min active recovery at 70% HRmax (4-AIT, the other group performed a single bout protocol that consisted of 1×4 min at 90% HRmax (1-AIT. Twenty-six inactive but otherwise healthy overweight men (BMI: 25-30, age: 35-45 y were randomized to either 1-AIT (n = 11 or 4-AIT (n = 13. After training, VO2max increased by 10% (∼5.0 mL⋅kg(-1⋅min(-1 and 13% (∼6.5 mL⋅kg(-1⋅min(-1 after 1-AIT and 4-AIT, respectively (group difference, p = 0.08. Oxygen cost during running at a sub-maximal workload was reduced by 14% and 13% after 1-AIT and 4-AIT, respectively. Systolic blood pressure decreased by 7.1 and 2.6 mmHg after 1-AIT and 4-AIT respectively, while diastolic pressure decreased by 7.7 and 6.1 mmHg (group difference, p = 0.84. Both groups had a similar ∼5% decrease in fasting glucose. Body fat, total cholesterol, LDL-cholesterol, and ox-LDL cholesterol only were significantly reduced after 4-AIT. Our data suggest that a single bout of AIT performed three times per week may be a time-efficient strategy to improve VO2max and reduce blood pressure and fasting glucose in previously inactive but otherwise healthy middle-aged individuals. The 1-AIT type of exercise training may be readily implemented as part of activities of daily living and could easily be translated into programs designed to improve public health

  13. Nicotinic receptors modulate the onset of reactive oxygen species production and mitochondrial dysfunction evoked by glutamate uptake block in the rat hypoglossal nucleus.

    Science.gov (United States)

    Tortora, Maria; Corsini, Silvia; Nistri, Andrea

    2017-02-03

    In several neurodegenerative diseases, glutamate-mediated excitotoxicity is considered to be a major process to initiate cell degeneration. Indeed, subsequent to excessive glutamate receptor stimulation, reactive oxygen species (ROS) generation and mitochondrial dysfunction are regarded as two major gateways leading to neuron death. These processes are mimicked in an in vitro model of rat brainstem slice when excitotoxicity is induced by DL-threo-β-benzyloxyaspartate (TBOA), a specific glutamate-uptake blocker that increases extracellular glutamate. Our recent study has demonstrated that brainstem hypoglossal motoneurons, which are very vulnerable to this damage, were neuroprotected from excitotoxicity with nicotine application through the activation of nicotinic acetylcholine receptors (nAChRs) and subsequent inhibition of ROS and mitochondrial dysfunction. The present study examined if endogenous cholinergic activity exerted any protective effect in this pathophysiological model and how ROS production (estimated with rhodamine fluorescence) and mitochondrial dysfunction (measured as methyltetrazolium reduction) were time-related during the early phase of excitotoxicity (0-4h). nAChR antagonists did not modify TBOA-evoked ROS production (that was nearly doubled over control) or mitochondrial impairment (25% decline), suggesting that intrinsic nAChR activity was insufficient to contrast excitotoxicity and needed further stimulation with nicotine to become effective. ROS production always preceded mitochondrial dysfunction by about 2h. Nicotine prevented both ROS production and mitochondrial metabolic depression with a delayed action that alluded to a complex chain of events targeting these two lesional processes. The present data indicate a relatively wide time frame during which strong nAChR activation can arrest a runaway neurotoxic process leading to cell death. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. The role of postural control in the association between aerobic capacity and walking capacity in chronic stroke: a cross-sectional analysis.

    Science.gov (United States)

    Outermans, Jacqueline C; van de Port, Ingrid; Kwakkel, Gert; Visser-Meily, Johanna M; Wittink, Harriet

    2018-03-12

    Reports on the association between aerobic capacity and walking capacity in people after stroke show disparate results. To determine (1) if the predictive validity of peak oxygen uptake (VO2peak) for walking capacity post stroke is different from that of maximal oxygen uptake (VO2max) and (2) if postural control, hemiplegic lower extremity muscle strength, age and gender distort the association between aerobic capacity and walking capacity. Cross-sectional study. General community in Utrecht, the Netherlands. Community-dwelling people more than three months after stroke. Measurement of aerobic capacity were performed with cardiopulmonary exercise testing (CPET) and differentiated between the achievement of VO2peak or VO2max. Measurement of walking capacity with the Six Minute Walk Test (6MWT), postural control with the Performance Oriented Mobility Assessment (POMA) and hemiplegic lower extremity muscle strength with the Motricity Index (MI-LE). Fifty-one out of 62 eligible participants, aged 64.7 (±12.5) years were included. Analysis of covariance (ANCOVA) showed a nonsignificant difference between the predictive validities of VO2max (N = 22, β = 0.56; 95%CI 0.12 - 0.97) and VO2peak (N = 29, β = 0.72; 95%CI 0.38 - 0.92). Multiple regression analysis of the pooled sample showed a significant decrease in the β value of VO2peak (21.6%) for the 6MWT when adding the POMA as a covariate in the association model. VO2peak remained significantly related to 6MWT after correcting for the POMA (β = 0.56 (95%CI 0.39 - 0.75)) CONCLUSIONS: The results suggest similar predictive validity of aerobic capacity for walking capacity in participants achieving VO2max compared to those only achieving VO2peak. Postural control confounds the association between aerobic capacity and walking capacity. Aerobic capacity remains a valid predictor of walking capacity. Aerobic capacity is an important factor associated with walking capacity after stroke. However, to understand this

  15. Objectively measured daily physical activity related to aerobic fitness in young children

    DEFF Research Database (Denmark)

    Dencker, Magnus; Bugge, Anna; Hermansen, Bianca

    2010-01-01

    The purpose of this study was to investigate by direct measurement the cross-sectional relationship between accelerometer-measured physical activity and peak oxygen uptake (VO(2peak): ml x min(-1) x kg(-1)), in a population-based cohort of young children, since such data are scarce. The study...... analyses indicated that the various physical activity variables explained between 2 and 8% of the variance in VO(2peak) in boys. In this population-based cohort, most daily activity variables were positively related to aerobic fitness in boys, whereas less clear relationships were observed in girls. Our...... finding that physical activity was only uniformly related to aerobic fitness in boys partly contradicts previous studies in older children and adolescents....

  16. Perioperative rehabilitation in operation for lung cancer (PROLUCA) – rationale and design

    DEFF Research Database (Denmark)

    Sommer, Maja S; Trier, Karen; Vibe-Petersen, Jette

    2014-01-01

    postoperative rehabilitation (starting six weeks after surgery); (3) early postoperative rehabilitation alone; (4) today's standard care which is postoperative rehabilitation initiated six weeks after surgery. The preoperative rehabilitation program consists of an individually designed, 30-minute home......-based exercise program performed daily. The postoperative rehabilitation program consists of a supervised group exercise program comprising cardiovascular and resistance training two-hour weekly for 12 weeks combined with individual counseling. The primary study endpoint is VO2peak and secondary endpoints...... (Maximal Oxygen Uptake (VO2peak)), 380 patients with non-small cell lung cancer (NSCLC) stage I-IIIa referred for surgical resection will be randomly assigned to one of four groups: (1) preoperative and early postoperative rehabilitation (starting two weeks after surgery); (2) preoperative and late...

  17. High intensity interval training in a real world setting: a randomized controlled feasibility study in overweight inactive adults, measuring change in maximal oxygen uptake.

    Directory of Open Access Journals (Sweden)

    Helen Lunt

    Full Text Available BACKGROUND: In research clinic settings, overweight adults undertaking HIIT (high intensity interval training improve their fitness as effectively as those undertaking conventional walking programs but can do so within a shorter time spent exercising. We undertook a randomized controlled feasibility (pilot study aimed at extending HIIT into a real world setting by recruiting overweight/obese, inactive adults into a group based activity program, held in a community park. METHODS: Participants were allocated into one of three groups. The two interventions, aerobic interval training and maximal volitional interval training, were compared with an active control group undertaking walking based exercise. Supervised group sessions (36 per intervention were held outdoors. Cardiorespiratory fitness was measured using VO2max (maximal oxygen uptake, results expressed in ml/min/kg, before and after the 12 week interventions. RESULTS: On ITT (intention to treat analyses, baseline (N = 49 and exit (N = 39 [Formula: see text]O2 was 25.3±4.5 and 25.3±3.9, respectively. Participant allocation and baseline/exit VO2max by group was as follows: Aerobic interval training N =  16, 24.2±4.8/25.6±4.8; maximal volitional interval training N = 16, 25.0±2.8/25.2±3.4; walking N = 17, 26.5±5.3/25.2±3.6. The post intervention change in VO2max was +1.01 in the aerobic interval training, -0.06 in the maximal volitional interval training and -1.03 in the walking subgroups. The aerobic interval training subgroup increased VO2max compared to walking (p = 0.03. The actual (observed, rather than prescribed time spent exercising (minutes per week, ITT analysis was 74 for aerobic interval training, 45 for maximal volitional interval training and 116 for walking (p =  0.001. On descriptive analysis, the walking subgroup had the fewest adverse events. CONCLUSIONS: In contrast to earlier studies, the improvement in cardiorespiratory fitness in a

  18. A REVIEW OF STATURE, BODY MASS AND MAXIMAL OXYGEN UPTAKE PROFILES OF U17, U20 AND FIRST DIVISION PLAYERS IN BRAZILIAN SOCCER

    Directory of Open Access Journals (Sweden)

    Cristiano Diniz Da Silva

    2008-09-01

    Full Text Available Investigations in the physiological demands of soccer have identified that a significant percentage of energy production in match performance is provided through the aerobic pathways. It is therefore important to assess maximal oxygen uptake (VO2Max of players in order to evaluate their aerobic fitness status and optimize their physical conditioning. However, it is also important to consider the variation of (VO2Max profiles for soccer players, with differences having been identified in terms of playing position as well as playing style. This paper reviews the academic literature between 1996 and 2006 and reports on the methodologies employed and the values obtained for stature, body mass and (VO2Max profiles of soccer players of different positions in professional Brazilian clubs at U-17, U-20 and First Division levels. Indirect measurements accounted for the majority of tests conducted at U-17 (70% and U-20 (84.6% levels whereas at First Division level almost half of the (VO2Max evaluations were performed by direct measurements (47.8%. The mean (VO2Max profiles obtained for outfield players in U-17 was 56.95 ± 3.60 ml·kg-1·min-1, 58.13 ± 3.21 ml·kg-1·min-1 for U-20 players and 56.58 ± 5.03 ml·kg-1·min-1 for First Division players. In Brazil, the U-20 players appear to have highest VO2Max values, however the profiles reported for all outfield positions in U-17 and First Division levels are often lower than those reported for the same category of players from other countries. This may be a reflection of the style of play used in Brazilian soccer. This is further emphasized by the fact that the playing position with the highest VO2Max values was the external defenders whereas most findings from studies performed in European soccer indicate that midfielders require the highest VO2Max values.

  19. Análisis de la relación entre el Yo-Yo Test y el consumo máximo de oxígeno en jóvenes jugadores de fútbol. [Analysis of the relationship between Yo-Yo Test and maximum oxygen uptake in young football players].

    Directory of Open Access Journals (Sweden)

    David Sánchez-Oliva

    2014-07-01

    Full Text Available This work aimed to examine the validity of the Yo-Yo Endurance Test Level 1 to estimate the maximum oxygen uptake in football players. Participants were 15 male football players, ranging in age from 17 to 19 years old (M = 17,9; DT = 0,67, who developed a laboratory test until exhaustion and Yo-Yo Test Level 1. Results showed significant differences in the values directly and indirectly obtained, being the values lower in the oxygen uptake estimated with Yo-Yo Test. Furthermore, Yo-Yo Test performance was not related with maximum oxygen uptake relative to weight on laboratory, showing that Yo-Yo Endurance Test Level 1, through the equation described by Bangsbo, Iaia, and Krustrup (2008 is not a valid test to estimate maximum oxygen uptake in young football players.

  20. Exercise physiology in heart failure and preserved ejection fraction.

    Science.gov (United States)

    Haykowsky, Mark J; Kitzman, Dalane W

    2014-07-01

    Recent advances in the pathophysiology of exercise intolerance in patients with heart failure with preserved ejection fraction (HFPEF) suggest that noncardiac peripheral factors contribute to the reduced peak V(o2) (peak exercise oxygen uptake) and to its improvement after endurance exercise training. A greater understanding of the peripheral skeletal muscle vascular adaptations that occur with physical conditioning may allow for tailored exercise rehabilitation programs. The identification of specific mechanisms that improve whole body and peripheral skeletal muscle oxygen uptake could establish potential therapeutic targets for medical therapies and a means to follow therapeutic response. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Assessing peak aerobic capacity in Dutch law enforcement officers

    NARCIS (Netherlands)

    Wittink, Harriet; Takken, Tim; de Groot, Janke; Reneman, Michiel; Peters, Roelof; Vanhees, Luc

    2015-01-01

    Objectives: To cross-validate the existing peak rate of oxygen consumption (VO2peak) prediction equations in Dutch law enforcement officers and to determine whether these prediction equations can be used to predict VO2peak for groups and in a single individual. A further objective was to report

  2. Assessing peak aerobic capacity in Dutch law enforcement officers.

    NARCIS (Netherlands)

    Wittink, H.; Takken, T.; Groot, J.F. de; Reneman, M.; Peters, R.; Vanhees, L.

    2015-01-01

    Objectives: To cross-validate the existing peak rate of oxygen consumption (VO2peak) prediction equations in Dutch law enforcement officers and to determine whether these prediction equations can be used to predict VO2peak for groups and in a single individual. A further objective was to report

  3. Rates of oxygen uptake increase independently of changes in heart rate in late stages of development and at hatching in the green iguana, Iguana iguana.

    Science.gov (United States)

    Sartori, Marina R; Abe, Augusto S; Crossley, Dane A; Taylor, Edwin W

    2017-03-01

    Oxygen consumption (VO 2 ), heart rate (f H ), heart mass (M h ) and body mass (M b ) were measured during embryonic incubation and in hatchlings of green iguana (Iguana iguana). Mean f H and VO 2 were unvarying in early stage embryos. VO 2 increased exponentially during the later stages of embryonic development, doubling by the end of incubation, while f H was constant, resulting in a 2.7-fold increase in oxygen pulse. Compared to late stage embryos, the mean inactive level of VO 2 in hatchlings was 1.7 fold higher, while f H was reduced by half resulting in a further 3.6 fold increase in oxygen pulse. There was an overall negative correlation between mean f H and VO 2 when data from hatchlings was included. Thus, predicting metabolic rate as VO 2 from measurements of f H is not possible in embryonic reptiles. Convective transport of oxygen to supply metabolism during embryonic incubation was more reliably indicated as an index of cardiac output (CO i ) derived from the product of f H and M h . However, a thorough analysis of factors determining rates of oxygen supply during development and eclosion in reptiles will require cannulation of blood vessels that proved impossible in the present study, to determine oxygen carrying capacity by the blood and arteriovenous oxygen content difference (A-V diff), plus patterns of blood flow. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Aerobic metabolism and cardioventilatory responses in paraplegic athletes during an incremental wheelchair exercise.

    Science.gov (United States)

    Vinet, A; Le Gallais, D; Bernard, P L; Poulain, M; Varray, A; Mercier, J; Micallef, J P

    1997-01-01

    The aims of the present study were: (1) to assess aerobic metabolism in paraplegic (P) athletes (spinal lesion level, T4-L3) by means of peak oxygen uptake (VO2peak) and ventilatory threshold (VT), and (2) to determine the nature of exercise limitation in these athletes by means of cardioventilatory responses at peak exercise. Eight P athletes underwent conventional spirographic measurements and then performed an incremental wheelchair exercise on an adapted treadmill. Ventilatory data were collected every minute using an automated metabolic system: ventilation (l x min[-1]), oxygen uptake (VO2, l x min[-1], ml x min[-1] x kg[-1]), carbon dioxide production (VCO2, ml x min[-1]), respiratory exchange ratio, breathing frequency and tidal volume. Heart rate (HR, beats x min[-1]) was collected with the aid of a standard electrocardiogram. VO2peak was determined using conventional criteria. VT was determined by the breakpoint in the VCO2 - VO2 relationship, and is expressed as the absolute VT (VO2, ml x min[-1] x kg[-1]) and relative VT (percentage of VO2peak). Spirometric values and cardioventilatory responses at rest and at peak exercise allowed the measurement of ventilatory reserve (VR), heart rate reserve (HRr), heart rate response (HRR), and O2 pulse (O2 P). Results showed a VO2peak value of 40.6 (2.5) ml x min(-1) x kg(-1), an absolute VT detected at 23.1 (1.5) ml x min(-1) x kg(-1) VO2 and a relative VT at 56.4 (2.2)% VO2peak. HRr [15.8 (3.2) beats min(-1)], HRR [48.6 (4.3) beat x l(-1)], and O2 P [0.23 (0.02) ml x kg(-1) x beat(-1)] were normal, whereas VR at peak exercise [42.7 (2.4)%] was increased. As wheelchair exercise excluded the use of an able-bodied (AB) control group, we compared our VO2peak and VT results with those for other P subjects and AB controls reported in the literature, and we compared our cardioventilatory responses with those for respiratory and cardiac patients. The low VO2peak values obtained compared with subject values obtained during

  5. In Nonobese Children, Fitness and BMI are Independent Predictors of Fasting Insulin.

    Science.gov (United States)

    Watson, Andrew M; Eickhoff, Jens; Nemeth, Blaise A; Carrel, Aaron L

    2015-05-01

    Although fitness and obesity have been shown to be independent predictors of cardiometabolic disease risk in obese children, this interaction is not well defined in nonobese children. The purpose of this study was to define the relationships between peak aerobic capacity, body composition, and fasting insulin levels in nonobese middle school children. 148 middle school children (mean age 11.0 ± 2.1 years, 49% male) underwent determination of body mass index (BMI) z-score, fasting glucose, fasting insulin, body composition by DXA scan (lean body mass and body fat percentage), and peak oxygen uptake per kg of lean body mass (VO2peak). Univariate correlations and multivariate regression analysis were used to identify independent predictors of fasting insulin using age, sex, percent body fat, body mass index z-score, and VO2peak. fasting insulin was significantly related to VO2peak (r =-0.37, p fasting insulin, while age (p = .39), sex (p = .49), and percent body fat (p = .72) did not. Among nonobese middle school children, fasting insulin is independently related to aerobic fitness after accounting for age, sex, and body composition. Public health efforts to reduce cardiometabolic disease risk among all adolescents should include exercise programs to increase cardiovascular fitness.

  6. Exercise Affects Cardiopulmonary Function in Patients with Chronic Kidney Disease: A Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Hongchang Yang

    2017-01-01

    Full Text Available This study aimed to comprehensively assess the effects of exercise on cardiopulmonary function indices in patients with chronic kidney disease (CKD. A literature review was performed by searching literatures in PubMed and Embase before June 2016. Studies were selected based on predefined inclusion and exclusion criteria, followed by data extraction and a quality assessment of the included studies using the Cochrane Collaboration’s tool. Correlations between exercise and cardiopulmonary function indices [pulse wave velocity, respiratory exchange ratio, and peak oxygen uptake (VO2 peak] were then evaluated using mean differences and 95% confidence intervals. All meta-analyses were conducted using R 3.12 software. Finally, five eligible studies involving 179 CKD patients were included. After intervention, a heterogeneity test showed that the VO2 peak values of the treatment group were greater than those of the control group, whereas no significant differences were found for the other indices. However, a sensitivity analysis showed inconsistent results both before and after intervention. Thus, we concluded that exercise might play an important role in improving the VO2 peak values in CKD patients. Additional studies are needed to verify this conclusion.

  7. No differences in cycling efficiency between world-class and recreational cyclists.

    Science.gov (United States)

    Moseley, L; Achten, J; Martin, J C; Jeukendrup, A E

    2004-07-01

    The aim of this experiment was to compare the efficiency of elite cyclists with that of trained and recreational cyclists. Male subjects (N = 69) performed an incremental exercise test to exhaustion on an electrically braked cycle ergometer. Cadence was maintained between 80 - 90 rpm. Energy expenditure was estimated from measures of oxygen uptake (VO (2)) and carbon dioxide production (VCO(2)) using stoichiometric equations. Subjects (age 26 +/- 7 yr, body mass 74.0 +/- 6.3 kg, Wpeak 359 +/- 40 W and VO(2)peak 62.3 +/- 7.0 mL/kg/min) were divided into 3 groups on the basis of their VO (2)peak ( 70 (High, N = 16) mL/kg/min). All data are mean +/- SE. Despite the wide range in aerobic capacities gross efficiency (GE) at 165 W (GE (165)), GE at the same relative intensity (GE (final)), delta efficiency (DE) and economy (EC) were similar between all groups. Mean GE (165) was 18.6 +/- 0.3 %, 18.8 +/- 0.4 % and 17.9 +/- 0.3 % while mean DE was 22.4 +/- 0.4 %, 21.6 +/- 0.4 % and 21.2 +/- 0.5 % (for Low, Medium and High, respectively). There was no correlation between GE (165), GE (final), DE or EC and VO(2)peak. Based on these data, we conclude that there are no differences in efficiency and economy between elite cyclists and recreational level cyclists.

  8. Effects of Modified Multistage Field Test on Performance and Physiological Responses in Wheelchair Basketball Players

    Science.gov (United States)

    Weissland, Thierry; Faupin, Arnaud; Borel, Benoit; Berthoin, Serge; Leprêtre, Pierre-Marie

    2015-01-01

    A bioenergetical analysis of manoeuvrability and agility performance for wheelchair players is inexistent. It was aimed at comparing the physiological responses and performance obtained from the octagon multistage field test (MFT) and the modified condition in “8 form” (MFT-8). Sixteen trained wheelchair basketball players performed both tests in randomized condition. The levels performed (end-test score), peak values of oxygen uptake (VO2peak), minute ventilation (VEpeak), heart rate (HRpeak), peak and relative blood lactate (Δ[Lact−] = peak – rest values), and the perceived rating exertion (RPE) were measured. MFT-8 induced higher VO2peak and VEpeak values compared to MFT (VO2peak: 2.5 ± 0.6 versus 2.3 ± 0.6 L·min−1 and VEpeak: 96.3 ± 29.1 versus 86.6 ± 23.4 L·min−1; P physiological responses than MFT. It could be explained by demands of wheelchair skills occurring in 8 form during the modified condition. PMID:25802841

  9. 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.

  10. Polarized training has greater impact on key endurance variables than threshold, high intensity or high volume training

    Directory of Open Access Journals (Sweden)

    Thomas eStöggl

    2014-02-01

    Full Text Available Endurance athletes integrate four conditioning concepts in their training programs: high-volume training (HVT, ‘threshold-training’ (THR, high-intensity interval training (HIIT and a combination of these aforementioned concepts known as polarized training (POL. The purpose of this study was to explore which of these four training concepts provides the greatest response on key components of endurance performance in well-trained endurance athletes. Methods: Forty eight runners, cyclists, triathletes and cross-country skiers (peak oxygen uptake: (VO2peak: 62.6±7.1 mL∙min-1∙kg-1 were randomly assigned to one of four groups performing over nine weeks. An incremental test, work economy and a VO2peak tests were performed. Training intensity was heart rate controlled. Results: POL demonstrated the greatest increase in VO2peak (+6.8 ml∙min∙kg-1 or 11.7%, P0.05. Conclusion: POL resulted in the greatest improvements in most key variables of endurance performance in well-trained endurance athletes. THR or HVT did not lead to further improvements in performance related variables.

  11. The effect of high-intensity training on mitochondrial fat oxidation in skeletal muscle and subcutaneous adipose tissue

    DEFF Research Database (Denmark)

    Larsen, Steen; Danielsen, J H; Søndergård, Stine Dam

    2015-01-01

    High-intensity interval training (HIT) is known to increase mitochondrial content in a similar way as endurance training [60-90% of maximal oxygen uptake (VO2peak )]. Whether HIT increases the mitochondria's ability to oxidize lipids is currently debated. We investigated the effect of HIT...... of HIT (three times per week at 298 ± 21 W). HIT significantly increased VO2peak from 2.9 ± 0.2 to 3.1 ± 0.2 L/min. No differences were seen in maximal fat oxidation in either skeletal muscle or adipose tissue. Km (app) for octanoyl carnitine or palmitoyl carnitine were similar after training in skeletal...... muscle and adipose tissue. Maximal OXPHOS capacity with complex I- and II-linked substrates was increased after training in skeletal muscle but not in adipose tissue. In conclusion, 6 weeks of HIT increased VO2peak . Mitochondrial content and mitochondrial OXPHOS capacity were increased in skeletal...

  12. Maximum Plant Uptakes for Water, Nutrients, and Oxygen Are Not Always Met by Irrigation Rate and Distribution in Water-based Cultivation Systems

    NARCIS (Netherlands)

    Blok, Chris; Jackson, Brian E.; Guo, Xianfeng; Visser, De Pieter H.B.; Marcelis, Leo F.M.

    2017-01-01

    Growing on rooting media other than soils in situ -i.e., substrate-based growing- allows for higher yields than soil-based growing as transport rates of water, nutrients, and oxygen in substrate surpass those in soil. Possibly water-based growing allows for even higher yields as transport rates of

  13. An attempt to quantify the placebo effect from a three-week simulated altitude training camp in elite race walkers.

    Science.gov (United States)

    Saunders, Philo U; Ahlgrim, Christoph; Vallance, Brent; Green, Daniel J; Robertson, Eileen Y; Clark, Sally A; Schumacher, Yorck O; Gore, Christopher J

    2010-12-01

    To quantify physiological and performance effects of hypoxic exposure, a training camp, the placebo effect, and a combination of these factors. Elite Australian and International race walkers (n = 17) were recruited, including men and women. Three groups were assigned: 1) Live High:Train Low (LHTL, n = 6) of 14 h/d at 3000 m simulated altitude; 2) Placebo (n = 6) of 14 h/d of normoxic exposure (600 m); and 3) Nocebo (n = 5) living in normoxia. All groups undertook similar training during the intervention. Physiological and performance measures included 10-min maximal treadmill distance, peak oxygen uptake (VO2peak), walking economy, and hemoglobin mass (Hbmass). Blinding failed, so the Placebo group was a second control group aware of the treatment. All three groups improved treadmill performance by approx. 4%. Compared with Placebo, LHTL increased Hbmass by 8.6% (90% CI: 3.5 to 14.0%; P = .01, very likely), VO2peak by 2.7% (-2.2 to 7.9%; P = .34, possibly), but had no additional improvement in treadmill distance (-0.8%, -4.6 to 3.8%; P = .75, unlikely) or economy (-8.2%, -24.1 to 5.7%; P = .31, unlikely). Compared with Nocebo, LHTL increased Hbmass by 5.5% (2.5 to 8.7%; P = .01, very likely), VO2peak by 5.8% (2.3 to 9.4%; P = .02, very likely), but had no additional improvement in treadmill distance (0.3%, -1.9 to 2.5%; P = .75, possibly) and had a decrease in walking economy (-16.5%, -30.5 to 3.9%; P = .04, very likely). Overall, 3-wk LHTL simulated altitude training for 14 h/d increased Hbmass and VO2peak, but the improvement in treadmill performance was not greater than the training camp effect.

  14. Effects of high-intensity interval training on cardiometabolic risk factors in overweight/obese women.

    Science.gov (United States)

    Smith-Ryan, Abbie E; Trexler, Eric T; Wingfield, Hailee L; Blue, Malia N M

    2016-11-01

    The purpose of this study was to evaluate two practical interval training protocols on cardiorespiratory fitness, lipids and body composition in overweight/obese women. Thirty women (mean ± SD; weight: 88.1 ± 15.9 kg; BMI: 32.0 ± 6.0 kg · m(2)) were randomly assigned to ten 1-min high-intensity intervals (90%VO2 peak, 1 min recovery) or five 2-min high-intensity intervals (80-100% VO2 peak, 1 min recovery) or control. Peak oxygen uptake (VO2 peak), peak power output (PPO), body composition and fasting blood lipids were evaluated before and after 3 weeks of training, completed 3 days per week. Results from ANCOVA analyses demonstrated no significant training group differences for any primary variables (P > 0.05). When training groups were collapsed, 1MIN and 2MIN resulted in a significant increase in PPO (∆18.9 ± 8.5 watts; P = 0.014) and time to exhaustion (∆55.1 ± 16.4 s; P = 0.001); non-significant increase in VO2 peak (∆2.36 ± 1.34 ml · kg(-)(1) · min(-)(1); P = 0.185); and a significant decrease in fat mass (FM) (-∆1.96 ± 0.99 kg; P = 0.011). Short-term interval exercise training may be effective for decreasing FM and improving exercise tolerance in overweight and obese women.

  15. Study of phase development and thermal stability in as synthesized TiO2 nanoparticles by laser pyrolysis: ethylene uptake and oxygen enrichment

    Science.gov (United States)

    Ilie, Alina Georgiana; Scarisoreanu, Monica; Dutu, Elena; Dumitrache, Florian; Banici, Ana-Maria; Fleaca, Claudiu Teodor; Vasile, Eugenia; Mihailescu, Ion

    2018-01-01

    Laser pyrolysis has proven a viable and trustworthy method of TiO2 nanoparticles fabrication, ensuring good quality and wide variety of nanoparticle morphologies and sizes. This work is aimed to phase control, experimentally studied, by parameter modulation, during one step laser pyrolysis synthesis or in combination with thermal annealing. High phase purity anatase and rutile TiO2 nanoparticles, oxygen abundant, are synthesized from TiCl4 and C2H4 gas mixtures, in the presence of air as oxygen donor, under CO2 laser radiation. The nano-titania samples are analyzed by X-ray Diffraction, EDAX, TEM and Raman spectroscopy and reveal good phase stability and distinct morphology. This study extends the method applicability onto rutile majoritarian TiO2 synthesis and generation of thermally stable anatase titania, a well-known catalyst.

  16. Metabolic changers in oxygen transport in patients with diabetes mellitus type 2. Possibilities for correction

    Directory of Open Access Journals (Sweden)

    I Z Bondarenko

    2009-06-01

    Full Text Available Diabetes mellitus type 2 (DM2 - is an independent predictor of development of heart failure (HF. Spiroergometry - is a method for studying blood gas exchange parameters, commonly used for specification of HF. The purpose: 1. To study features of gas exchange at patients with DM2 without cardiovascular diseases in comparison with healthy control. 2. To estimate efficiency of metoprolol for correction of metabolic disturbances in patients with DM2. Materials and methods: 12 patients with DM2, aged 48,4±8, without history of cardiovascular diseases and 15 control subjects, aged 43,6±8 underwent cardio-pulmonary exercise test on treadmill, according to Bruce protocol. Exercise energy, VO2 peak, MET, VE max, VCO2 production were observed. Results: Patients with DM2 had a reduced exercise duration (p<0,001, lower peak oxygen consumption (p<0,001, VCO2 production and MET (p<0,005, than controls, representing the same state of hypoxia as in patients with ischemic heart disease (IHD of functional class 2. The introduction of metoprolol to patients with DM2 significantly increased exercise duration time and VCO2 production (p<0,005. Conclusions: 1. VO2 consumption in patients with DM2 is decreased to the same levels as in persons without DM2, who have IHD and HF. 2. Changes in oxygen-transport in persons with DM2 may serve as a marker of negative influence of the disease on cardiovascular system status. 3. Metoprolol improves parameters of cardio-respiratory system in patients with DM2.

  17. Alterations of serum concentrations of thyroid hormones and sex hormone-binding globulin, nuclear binding of tri-iodothyronine and thyroid hormone-stimulated cellular uptake of oxygen and glucose in mononuclear blood cells from patients with non-thyroidal illness

    DEFF Research Database (Denmark)

    Kvetny, J; Matzen, L

    1990-01-01

    Nuclear tri-iodothyronine (T3) binding and thyroid hormone-stimulated oxygen consumption and glucose uptake were examined in mononuclear blood cells from patients with non-thyroidal illness (NTI) in which serum T3 was significantly (P less than 0.05) depressed (0.62 +/- 0.12 (S.D.) nmol/l) compared...

  18. Influence of mechanical disintegration on the microbial growth of aerobic sludge biomass: A comparative study of ultrasonic and shear gap homogenizers by oxygen uptake measurements.

    Science.gov (United States)

    Divyalakshmi, P; Murugan, D; Sivarajan, M; Saravanan, P; Lajapathi Rai, C

    2015-11-01

    Wastewater treatment plant incorporates physical, chemical and biological processes to treat and remove the contaminants. The main drawback of conventional activated sludge process is the huge production of excess sludge, which is an unavoidable byproduct. The treatment and disposal of excess sludge costs about 60% of the total operating cost. The ideal way to reduce excess sludge production during wastewater treatment is by preventing biomass formation within the aerobic treatment train rather than post treatment of the generated sludge. In the present investigation two different mechanical devices namely, Ultrasonic and Shear Gap homogenizers have been employed to disintegrate the aerobic biomass. This study is intended to restrict the multiplication of microbial biomass and at the same time degrade the organics present in wastewater by increasing the oxidative capacity of microorganisms. The disintegrability on biomass was determined by biochemical methods. Degree of inactivation provides the information on inability of microorganisms to consume oxygen upon disruption. The soluble COD quantifies the extent of release of intra cellular compounds. The participation of disintegrated microorganism in wastewater treatment process was carried out in two identical respirometeric reactors. The results show that Ultrasonic homogenizer is very effective in the disruption of microorganisms leading to a maximum microbial growth reduction of 27%. On the other hand, Shear gap homogenizer does not favor the sludge growth reduction rather it facilitates the growth. This study also shows that for better microbial growth reduction, floc size reduction alone is not sufficient but also microbial disruption is essential. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Coordination polymers of Fe(iii) and Al(iii) ions with TCA ligand: distinctive fluorescence, CO2 uptake, redox-activity and oxygen evolution reaction.

    Science.gov (United States)

    Dhara, Barun; Sappati, Subrahmanyam; Singh, Santosh K; Kurungot, Sreekumar; Ghosh, Prasenjit; Ballav, Nirmalya

    2016-04-28

    Fe and Al belong to different groups in the periodic table, one from the p-block and the other from the d-block. In spite of their different groups, they have the similarity of exhibiting a stable 3+ oxidation state. Here we have prepared Fe(iii) and Al(iii) based coordination polymers in the form of metal-organic gels with the 4,4',4''-tricarboxyltriphenylamine (TCA) ligand, namely Fe-TCA and Al-TCA, and evaluated some important physicochemical properties. Specifically, the electrical conductivity, redox-activity, porosity, and electrocatalytic activity (oxygen evolution reaction) of the Fe-TCA system were noted to be remarkably higher than those of the Al-TCA system. As for the photophysical properties, almost complete quenching of the fluorescence originating from TCA was observed in case of the Fe-TCA system, whereas for the Al-TCA system a significant retention of fluorescence with red-shifted emission was observed. Quantum mechanical calculations based on density functional theory (DFT) were performed to unravel the origin of such discriminative behaviour of these coordination polymer systems.

  20. High Intensity Interval Training Leads to Greater Improvements in Acute Heart Rate Recovery and Anaerobic Power as High Volume Low Intensity Training

    OpenAIRE

    Thomas L. Stöggl; Glenn Björklund; Glenn Björklund

    2017-01-01

    The purpose of the current study was to explore if training regimes utilizing diverse training intensity distributions result in different responses on neuromuscular status, anaerobic capacity/power and acute heart rate recovery (HRR) in well-trained endurance athletes.Methods: Thirty-six male (n = 33) and female (n = 3) runners, cyclists, triathletes and cross-country skiers [peak oxygen uptake: (VO2peak): 61.9 ± 8.0 mL·kg−1·min−1] were randomly assigned to one of three groups (blocked high ...

  1. Repeated Excessive Exercise Attenuates the Anti-Inflammatory Effects of Exercise in Older Men

    Directory of Open Access Journals (Sweden)

    Ronni E. Sahl

    2017-06-01

    Full Text Available Introduction/Purpose: A number of studies have investigated the effect of training with a moderate exercise dose (3–6 h/weekly on the inflammatory profile in blood, and the data are inconsistent. Cross-sectional studies indicate a positive effect of physical activity level on inflammation levels and risk of metabolic disease. However, it is not clear whether this may be dose dependent and if very prolonged repeated exercise therefore may be beneficial for low-grade inflammation. Based on this we studied how excessive repeated prolonged exercise influenced low-grade inflammation and adipose tissue anti-inflammatory macrophage content in six older male recreationally trained cyclists. Low-grade inflammation and adipose tissue macrophage content were investigated in six older trained men (age: 61 ± 4 years; VO2peak: 48 ± 2 mL kg−1 min−1 following repeated prolonged exercise.Methods: Cycling was performed daily for 14 days covering in total 2,706 km (1,681 miles. Maximal oxygen uptake (VO2peak was measured before and after the cycling. Duration and intensity of the exercise were determined from heart rates sampled during cycling. An adipose tissue biopsy from subcutaneous abdominal fat and a blood sample were obtained at rest in the overnight fasted state before and after the cycling. Anti-inflammatory adipose tissue macrophages (ATM were immunohistochemically stained in cross sectional sections using a CD163 binding antibody. The ATM and adipocyte sizes were analyzed blindly.Results: The cyclists exercised daily for 10 h and 31 ± 37 min and average intensity was 53 ± 1% of VO2peak. Body weight remained unchanged and VO2peak decreased by 6 ± 2% (P = 0.04. Plasma inflammatory cytokines, TNFα and IL-18 remained unchanged, as did hsCRP, but plasma IL-6 increased significantly. CD163 macrophage content remained unchanged, as did adipocyte cell size. The HbA1c was not significantly decreased, but there was a trend (P < 0.07 toward an

  2. CFTR Genotype and Maximal Exercise Capacity in Cystic Fibrosis: A Cross-sectional Study.

    Science.gov (United States)

    Radtke, Thomas; Hebestreit, Helge; Gallati, Sabina; Schneiderman, Jane E; Braun, Julia; Stevens, Daniel; Hulzebos, Erik Hj; Takken, Tim; Boas, Steven R; Urquhart, Don S; Lands, Larry C; Tejero, Sergio; Sovtic, Aleksandar; Dwyer, Tiffany; Petrovic, Milos; Harris, Ryan A; Karila, Chantal; Savi, Daniela; Usemann, Jakob; Mei-Zahav, Meir; Hatziagorou, Elpis; Ratjen, Felix; Kriemler, Susi

    2018-02-01

    Cystic fibrosis transmembrane conductance regulator (CFTR) is expressed in human skeletal muscle cells. Variations of CFTR dysfunction among patients with cystic fibrosis may be an important determinant of maximal exercise capacity in cystic fibrosis. Previous studies on the relationship between CFTR genotype and maximal exercise capacity are scarce and contradictory. This study was designed to explore factors influencing maximal exercise capacity, expressed as peak oxygen uptake (V.O2peak), with a specific focus on CFTR genotype in children and adults with cystic fibrosis. In an international, multicenter, cross-sectional study, we collected data on CFTR genotype and cardiopulmonary exercise tests in patients with cystic fibrosis who were ages 8 years and older. CFTR mutations were classified into functional classes I–V. The final analysis included 726 patients (45% females; age range, 8–61 yr; forced expiratory volume in 1 s, 16 to 123% predicted) from 17 cystic fibrosis centers in North America, Europe, Australia, and Asia, all of whom had both valid maximal cardiopulmonary exercise tests and complete CFTR genotype data. Overall, patients exhibited exercise intolerance (V.O2peak, 77.3 ± 19.1% predicted), but values were comparable among different CFTR classes. We did not detect an association between CFTR genotype functional classes I–III and either V.O2peak (percent predicted) (adjusted β = −0.95; 95% CI, −4.18 to 2.29; P = 0.57) or maximum work rate (Wattmax) (adjusted β = −1.38; 95% CI, −5.04 to 2.27; P = 0.46) compared with classes IV–V. Those with at least one copy of a F508del-CFTR mutation and one copy of a class V mutation had a significantly lower V.O2peak (β = −8.24%; 95% CI, −14.53 to −2.99; P = 0.003) and lower Wattmax (adjusted β = −7.59%; 95% CI, −14.21 to −0.95; P = 0.025) than those with two copies of a class II mutation. On the basis of linear regression analysis adjusted for

  3. Effects of a high-intensity interval training program versus a moderate-intensity continuous training program on maximal oxygen uptake and blood pressure in healthy adults: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Arboleda Serna, Víctor Hugo; Arango Vélez, Elkin Fernando; Gómez Arias, Rubén Darío; Feito, Yuri

    2016-08-18

    Participation in aerobic exercise generates increased cardiorespiratory fitness, which results in a protective factor for cardiovascular disease and all-cause mortality. High-intensity interval training might cause higher increases in cardiorespiratory fitness in comparison with moderate-intensity continuous training; nevertheless, current evidence is not conclusive. To our knowledge, this is the first study to test the effect of high-intensity interval training with total load duration of 7.5 min per session. A randomized controlled trial will be performed on two groups of healthy, sedentary male volunteers (n = 44). The study protocol will include 24 exercise sessions, three times a week, including aerobic training on a treadmill and strength training exercises. The intervention group will perform 15 bouts of 30 s, each at an intensity between 90 % and 95 % of maximal heart rate. The control group will complete 40 min of continuous exercise, ranging between 65 % and 75 % of maximal heart rate. The primary outcome measure to be evaluated will be maximal oxygen uptake (VO2max), and systolic and diastolic blood pressure will be evaluated as secondary outcome measures. Waist circumference, body mass index, and body composition will also be evaluated. Epidemiological evidence shows the link between VO2max and its association with chronic conditions that trigger CVD. Therefore, finding ways to improve VO2max and reduce blood pressure it is of vital importance to public health. NCT02288403 . Registered on 4 November 2014.

  4. Assessing peak aerobic capacity in Dutch law enforcement officers

    Directory of Open Access Journals (Sweden)

    Harriet Wittink

    2015-06-01

    Full Text Available Objectives: To cross-validate the existing peak rate of oxygen consumption (VO2peak prediction equations in Dutch law enforcement officers and to determine whether these prediction equations can be used to predict VO2peak for groups and in a single individual. A further objective was to report normative absolute and relative VO2peak values of a sample of law enforcement officers in the Netherlands. Material and Methods: The peak rate of oxygen consumption (ml×kg–1×min–1 was measured using a maximal incremental bicycle test in 1530 subjects, including 1068 male and 461 female police officers. Validity of the prediction equations for groups was assessed by comparing predicted VO2peak with measured VO2peak using paired t-tests. For individual differences limits of agreement (LoA were calculated. Equations were considered valid for individuals when the difference between measured and predicted VO2peak did not exceed ±1 metabolic equivalent (MET in 95% of individuals. Results: None of the equations met the validity criterion of 95% of individuals having ±1 MET difference or less than the measured value. Limits of agreement (LoAs were large in all predictions. At the individual level, none of the equations were valid predictors of VO2peak (ml×kg–1×min–1. Normative values for Dutch law enforcement officers were presented. Conclusions: Substantial differences between measured and predicted VO2peak (ml×kg–1×min–1 were found. Most tested equations were invalid predictors of VO2peak at group level and all were invalid at individual levels.

  5. Oxygen Uptake - Live Hauling of Fish

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In certain markets, live fish can be sold for substantially higher prices than fresh dressed fish. A significant live-haul industry has developed in the U.S. and...

  6. Peak oxygen uptake in swimmers and pupils

    Directory of Open Access Journals (Sweden)

    Emilson Colantonio

    2008-01-01

    The objectives of this study were: a to analyze the behavior of VO2MAX (absolute and relative of males of different age groups sex; b to compare VO2MAX (absolute and relative, of swimmers (SWM and schoolchildren (SCH in the same age groups. Seventy-one boys aged 7-17 years were evaluated (35 SWM and 36 SCH and distributed into the age groups 7-10, 11-14 and 15-17 years. Anthropometric measurements were taken (height, body mass and sum of skin folds and the metabolic (VO2MAX tests were carried out using VO2000® gas analysis and an Inbrasport ATL® treadmill, using a modified version of the Bruce protocol. Statistical analysis: ANOVA for repeated measures, followed by Tukey’s post hoc test (p<0.05. Absolute VO2MAX: there were statistically significant differences between all age groups and between SWM (0.99 + 0.20 and 1.27 + 0.21 L.min-1 and SCH (0.98 + 0.36 and 0.80 + 0.12 L.min-1. Relative VO2MAX: there were statistically significant differences between SWM1 and SWM2 (10.88 + 0.09 and 0.75 + 0.47 ml.kg-1.min-1 and between SCH1 and SCH3 (6.96 + 1.23 and 0.98 + 2.29 ml.kg-1.min-1, although SWM and SCH were different. The results indicate that VO2MAX increased as the subjects got older, which is the result of natural development. However, the effect of swimming training predominated. Although the behavior of the variable was similar for the 11-14 and 15-17 age groups, the figures for SWM and SCH are different at these ages, with the swimmers having higher VO2MAX.

  7. empirical modeling of oxygen modeling of oxygen uptake of flow

    African Journals Online (AJOL)

    eobe

    structure. Keywords: stepped chute, skimming flow, aeration l. 1. INTRODUCTION ..... [3] Toombes, L. and Chanson, H., “Air-water flow and gas transfer at aeration ... of numerical model of the flow behaviour through smooth and stepped.

  8. Oxygen uptake and haemocyanin oxygen affinity of Potamonautes ...

    African Journals Online (AJOL)

    The MO2 values for exhaustively exercised crabs in water medium or air medium are nearly twice the values found for pre-exercised crabs. The l-lactate concentration in the haemolymph increases from 0,75 ± 0,37 mmol to 9,63 ± 2,1 mmol in P. warreni after air exercise, a value similar to those for other terrestrial and ...

  9. Oxygen uptake and baemocyanin oxygen affinity of Potamonautes ...

    African Journals Online (AJOL)

    1988-11-01

    Nov 1, 1988 ... water as respiratory media with those of resting control crabs. Data on such ... and neutralization with a fully enzymatic kit (no. 256773) ..... times lower at resting conditions and twice as low for ..... Plenum Press, New York.

  10. Relationships Between Glycemic Control and Cardiovascular Fitness.

    Science.gov (United States)

    Moxley, Elizabeth W; Smith, Donald; Quinn, Lauretta; Park, Chang

    2018-07-01

    Diabetes is a serious health problem affecting approximately 29.1 million individuals in the United States. Another 86 million have prediabetes. The development and implementation of lifestyle modifications such as physical activity for these persons are among the most effective methods for prevention and treatment. The aim of this study was to examine relationships between glycemic control (HbA1c) and cardiovascular fitness (peak maximal oxygen uptake [VO 2 peak] and ventilatory threshold [VT]) in overweight/obese subjects with and without type 2 diabetes (T2DM). In addition, the influences of body mass index (BMI) and insulin sensitivity (homeostasis model assessment [HOMA %S]) on the relationship between glycemic control and cardiovascular fitness were explored. Data were abstracted from a completed study that included 51 overweight or obese subjects with T2DM ( n = 18), impaired glucose tolerance ( n = 8), or normal glucose tolerance ( n = 25). Relationships between glycemic control (HbA1c) and cardiovascular fitness (VO 2 peak and VT) were determined using correlational analysis and multiple linear regression analyses. A statistically significant relationship was observed between HbA1c and cardiovascular fitness. However, BMI and HOMA %S did not influence the relationship between glycemic control and cardiovascular fitness. HbA1c contributes to VO 2 peak and VT in obese and overweight subjects across glucose tolerance categories. Significant results were achieved despite the fact that there was a limited range of HbA1c based on the study inclusion criteria. This finding suggests that even a mild decrease in glycemic control can negatively influence cardiovascular fitness.

  11. Longitudinal relationship between wheelchair exercise capacity and life satisfaction in patients with spinal cord injury: A cohort study in the Netherlands

    Science.gov (United States)

    van Koppenhagen, Casper Floris; Post, Marcel; de Groot, Sonja; van Leeuwen, Christel; van Asbeck, Floris; Stolwijk-Swüste, Janneke; van der Woude, Lucas; Lindeman, Eline

    2014-01-01

    Objective To examine the relationship between wheelchair exercise capacity and life satisfaction in persons with spinal cord injury from the start of active inpatient rehabilitation up to 5 years after discharge. Design Prospective cohort study. Subjects Persons with spinal cord injury, aged 18–65 years, and wheelchair dependent at least for long distances. Method Measurements at the start of active rehabilitation, after 3 months, at discharge from inpatient rehabilitation, and 1 and 5 years after discharge. A peak wheelchair exercise test was performed to record peak oxygen uptake (VO2peak) and peak power output (POpeak). Life satisfaction was measured as current life satisfaction and change of life satisfaction in comparison with life after spinal cord injury. Relationships between (changes in) exercise capacity and (changes in) life satisfaction were analyzed random coefficient analysis, corrected for possible confounders (age, gender, level of lesion, functional status, secondary impairments, pain, and sports activity) if necessary. Results Of 225 persons included, 130 attended two or more peak exercise tests, who were include in the analyses. Mean age at start was 39 years, 75% were male, 73% had paraplegia, and 76% had a traumatic lesion. Mean POpeak increased during the study from 32.9 to 55.9 Watts, mean VO2peak from 1.02  to 1.38 l/minute, and mean life satisfaction from 5.7 to 7.8. An increase of POpeak with 10 W was associated with a 0.3-point increase of life satisfaction (P = 0.01). An increase of VO2peak with 0.1 l/minute was associated with a 0.1-point increase of life satisfaction (P = 0.049). Conclusion High(er) wheelchair exercise capacity is related to high(er) life satisfaction in spinal cord injury patients. PMID:24621019

  12. Acute effect of exercise intensity and duration on acylated ghrelin and hunger in men.

    Science.gov (United States)

    Broom, David R; Miyashita, Masashi; Wasse, Lucy K; Pulsford, Richard; King, James A; Thackray, Alice E; Stensel, David J

    2017-03-01

    Acute exercise transiently suppresses the orexigenic gut hormone acylated ghrelin, but the extent to which exercise intensity and duration determine this response is not fully understood. The effects of manipulating exercise intensity and duration on acylated ghrelin concentrations and hunger were examined in two experiments. In experiment one, nine healthy males completed three, 4-h conditions (control, moderate-intensity running (MOD) and vigorous-intensity running (VIG)), with an energy expenditure of ~2.5 MJ induced in both MOD (55-min running at 52% peak oxygen uptake (V.O 2peak )) and VIG (36-min running at 75% V.O 2peak ). In experiment two, nine healthy males completed three, 9-h conditions (control, 45-min running (EX45) and 90-min running (EX90)). Exercise was performed at 70% V.O 2peak In both experiments, participants consumed standardised meals, and acylated ghrelin concentrations and hunger were quantified at predetermined intervals. In experiment one, delta acylated ghrelin concentrations were lower than control in MOD (ES = 0.44, P = 0.01) and VIG (ES = 0.98, P Hunger ratings were similar across the conditions (P = 0.35). In experiment two, delta acylated ghrelin concentrations were lower than control in EX45 (ES = 0.77, P Hunger ratings were lower than control in EX45 (ES = 0.20, P = 0.01) and EX90 (ES = 0.27, P = 0.001); EX45 and EX90 were similar (ES = 0.07, P = 0.34). Hunger and delta acylated ghrelin concentrations remained suppressed at 1.5 h in EX90 but not EX45. In conclusion, exercise intensity, and to a lesser extent duration, are determinants of the acylated ghrelin response to acute exercise. © 2017 Society for Endocrinology.

  13. Effects of a short-term personalized Intermittent Work Exercise Program (IWEP) on maximal cardio-respiratory function and endurance parameters among healthy young and older seniors.

    Science.gov (United States)

    Vogel, T; Leprêtre, P-M; Brechat, P-H; Lonsdorfer, E; Benetos, A; Kaltenbach, G; Lonsdorfer, J

    2011-12-01

    The aim of this study was to evaluate the efficiency of a short-term Intermittent Work Exercise Program (IWEP) among healthy elderly subjects. This longitudinal prospective study took place at the Strasbourg University Hospital geriatric department. One hundred and fifty older volunteers, previously determined as being free from cardiac and pulmonary disease, were separated into two age groups: the "young senior" (60.2 ± 3.1 yr) and the "older senior" groups (70.8 ± 5.2 yr). These groups were then subdivided by gender into the "young female senior", "young male senior" "older female senior" and "older male senior" groups. Before and after the IWEP, all subjects were asked to perform an incremental cycle exercise to obtain their first ventilatory threshold (VT1), maximal tolerated power (MTP), peak oxygen uptake (VO2peak) and maximal minute ventilation (MMV). The IWEP consisted of a 30-min cycling exercise which took place twice a week, and was divided into six 5-min stages consisting of 4 min at VT1 intensity and 1 min at 90% MTP. An assessment was made of the effects of the IWEP on maximal cardio-respiratory function (MTP, VO2peak, MMV) and endurance parameters (VT1, heart rate [HR] measured at pretraining VT1 and lactate concentrations at pre-training MTP). This short-term training program resulted in a significant increase of MTP (from 13.2% to 20.6%), VO2peak (from 8.9% to 16.6%) and MMV (from 11.1% to 21.8%) in all groups (pseniors" were not significantly different (p>0.05) from the "young seniors" pre-training values for the same parameters. The most striking finding in this study is that after only 9 weeks, our short-term "individually-tailored" IWEP significantly improved both maximal cardio-respiratory function and endurance parameters in healthy, previously untrained seniors.

  14. AEROBIC POWER IN CHILD, CADET AND SENIOR JUDO ATHLETES

    Directory of Open Access Journals (Sweden)

    Elena Pocecco

    2012-07-01

    Full Text Available The aim of the present study was to compare performance and physiological responses during arm and leg aerobic power tests of combat duration in male child, cadet and senior judo athletes. Power output and physiological parameters, i.e., peak oxygen uptake ( ·VO2peak, peak ventilation, peak heart rate, lactate, and rate of perceived exertion, of 7 child (under 15 years: age class U15, 12.7 ± 1.1 yrs, 10 cadet (U17, 14.9 ± 0.7 yrs and 8 senior ( 20, 29.3 ± 9.2 yrs male judo athletes were assessed during incremental tests of combat duration on an arm crank and a cycle ergometer. Children as well as cadets demonstrated higher upper body relative VO2peak than seniors (37.3 ± 4.9, 39.2 ± 5.0 and 31.0 ± 2.1 ml∙kg-1∙min-1, respectively; moreover, upper and lower body relative VO2peak decreased with increasing age (r = -0.575, p < 0.003 and r = -0.580, p < 0.002, respectively. Children showed lower blood lactate concentrations after cranking as well as after cycling when compared to seniors (7.8 ± 2.4 vs. 11.4 ± 2.1 mmol∙l-1 and 7.9 ± 3.0 vs. 12.0 ± 1.9 mmol���l-1, respectively; furthermore, blood lactate values after cranking increased with age (r = 0.473, p < 0.017. These differences should be considered in planning the training for judo athletes of different age classes.

  15. Longitudinal relationship between wheelchair exercise capacity and life satisfaction in patients with spinal cord injury: A cohort study in the Netherlands.

    Science.gov (United States)

    van Koppenhagen, Casper Floris; Post, Marcel; de Groot, Sonja; van Leeuwen, Christel; van Asbeck, Floris; Stolwijk-Swüste, Janneke; van der Woude, Lucas; Lindeman, Eline

    2014-05-01

    To examine the relationship between wheelchair exercise capacity and life satisfaction in persons with spinal cord injury from the start of active inpatient rehabilitation up to 5 years after discharge. Prospective cohort study. Persons with spinal cord injury, aged 18-65 years, and wheelchair dependent at least for long distances. Measurements at the start of active rehabilitation, after 3 months, at discharge from inpatient rehabilitation, and 1 and 5 years after discharge. A peak wheelchair exercise test was performed to record peak oxygen uptake (VO2peak) and peak power output (POpeak). Life satisfaction was measured as current life satisfaction and change of life satisfaction in comparison with life after spinal cord injury. Relationships between (changes in) exercise capacity and (changes in) life satisfaction were analyzed random coefficient analysis, corrected for possible confounders (age, gender, level of lesion, functional status, secondary impairments, pain, and sports activity) if necessary. Of 225 persons included, 130 attended two or more peak exercise tests, who were include in the analyses. Mean age at start was 39 years, 75% were male, 73% had paraplegia, and 76% had a traumatic lesion. Mean POpeak increased during the study from 32.9 to 55.9 Watts, mean VO2peak from 1.02 to 1.38 l/minute, and mean life satisfaction from 5.7 to 7.8. An increase of POpeak with 10 W was associated with a 0.3-point increase of life satisfaction (P = 0.01). An increase of VO2peak with 0.1 l/minute was associated with a 0.1-point increase of life satisfaction (P = 0.049). Conclusion High(er) wheelchair exercise capacity is related to high(er) life satisfaction in spinal cord injury patients.

  16. Individual responses to combined endurance and strength training in older adults.

    Science.gov (United States)

    Karavirta, Laura; Häkkinen, Keijo; Kauhanen, Antti; Arija-Blázquez, Alfredo; Sillanpää, Elina; Rinkinen, Niina; Häkkinen, Arja

    2011-03-01

    A combination of endurance and strength training is generally used to seek further health benefits or enhanced physical performance in older adults compared with either of the training modes alone. The mean change within a training group, however, may conceal a wide range of individual differences in the responses. The purpose, therefore, was to examine the individual trainability of aerobic capacity and maximal strength, when endurance and strength training are performed separately or concurrently. For this study, 175 previously untrained volunteers, 89 men and 86 women between the ages of 40 and 67 yr, completed a 21-wk period of either strength training (S) twice a week, endurance training (E) twice a week, combined training (ES) four times per week, or served as controls. Training adaptations were quantified as peak oxygen uptake (VO2peak) in a bicycle ergometer test to exhaustion and maximal isometric bilateral leg extension force (MVC) in a dynamometer. A large range in training responses, similar to endurance or strength training alone, was also observed with combined endurance and strength training in both ΔVO2peak (from -8% to 42%) and ΔMVC (from -12% to 87%). There were no significant correlations between the training responses in VO2peak and MVC in the E, S, or especially in the ES group, suggesting that the same subjects did not systematically increase both aerobic capacity and maximal strength. The goal of combined endurance and strength training--increasing both aerobic capacity and maximal strength simultaneously--was only achieved by some of the older subjects. New means are needed to personalize endurance, strength, and especially combined endurance and strength training programs for optimal individual adaptations.

  17. Physiological characteristics of badminton match play.

    Science.gov (United States)

    Faude, Oliver; Meyer, Tim; Rosenberger, Friederike; Fries, Markus; Huber, Günther; Kindermann, Wilfried

    2007-07-01

    The present study aimed at examining the physiological characteristics and metabolic demands of badminton single match play. Twelve internationally ranked badminton players (eight women and four men) performed an incremental treadmill test [VO(2peak = )50.3 +/- 4.1 ml min(-1) kg(-1) (women) and 61.8 +/- 5.9 ml min(-1) kg(-1) (men), respectively]. On a separate day, they played a simulated badminton match of two 15 min with simultaneous gas exchange (breath-by-breath) and heart rate measurements. Additionally, blood lactate concentrations were determined before, after 15 min and at the end of the match. Furthermore, the duration of rallies and rests in between, the score as well as the number of shots per rally were recorded. A total of 630 rallies was analysed. Mean rally and rest duration were 5.5 +/- 4.4 s and 11.4 +/- 6.0 s, respectively, with an average 5.1 +/- 3.9 shots played per rally. Mean oxygen uptake (VO(2)), heart rate (HR), and blood lactate concentrations during badminton matches were 39.6 +/- 5.7 ml min(-1) kg(-1) (73.3% VO(2peak)), 169 +/- 9 min(-1) (89.0% HR(peak)) and 1.9 +/- 0.7 mmol l(-1), respectively. For a single subject 95% confidence intervals for VO(2) and HR during match play were on average 45.7-100.9% VO(2peak) and 78.3-99.8% HR(peak). High average intensity of badminton match play and considerable variability of several physiological variables demonstrate the importance of anaerobic alactacid and aerobic energy production in competitive badminton. A well-developed aerobic endurance capacity seems necessary for fast recovery between rallies or intensive training workouts.

  18. Maximal exercise capacity in patients with obstructive sleep apnoea syndrome: A systematic review and meta-analysis.

    Science.gov (United States)

    Mendelson, Monique; Marillier, Mathieu; Bailly, Sébastien; Flore, Patrice; Borel, Jean-Christian; Vivodtzev, Isabelle; Doutreleau, Stéphane; Tamisier, Renaud; Pépin, Jean-Louis; Verges, Samuel

    2018-04-26

    Maximal aerobic capacity is a strong health predictor and peak oxygen consumption (VO 2peak ) is considered a reflection of total body health. No systematic reviews or meta-analysis' to date have synthesised the existing data regarding VO 2peak in patients with obstructive sleep apnoea (OSA).A systematic review of English and French articles using Pubmed/Medline and Embase included studies assessing VO 2peak of OSA patients in mL·kg -1 ·min -1 compared with controls or in % predicted. Two independent reviewers analysed the studies, extracted the data and assessed the quality of evidence.Mean VO 2peak expressed in mL·kg -1 ·min -1 was significantly lower in patients with OSA when compared with controls (mean difference=-2.7 mL·kg -1 ·min -1 ; p<0.001; n=850). This reduction in VO 2peak was found to be larger in non-obese patients (BMI<30 kg·m -2 ). Mean VO 2peak in % predicted was 90.7±21.0% in OSA patients (n=643).OSA patients present reduced maximal aerobic capacity, which can be associated with increased cardiovascular risks and reduced survival in certain patient subgroups. Maximal exercise testing can be useful to characterise functional limitation and to evaluate health status in OSA patients. Registration # CRD42017057319. Copyright ©ERS 2018.

  19. Analysis of swimming performance from physical, physiological, and biomechanical parameters in young swimmers.

    Science.gov (United States)

    Jürimäe, Jaak; Haljaste, Kaja; Cicchella, Antonio; Lätt, Evelin; Purge, Priit; Leppik, Aire; Jürimäe, Toivo

    2007-02-01

    The purpose of this study was to examine the influence of the energy cost of swimming, body composition, and technical parameters on swimming performance in young swimmers. Twenty-nine swimmers, 15 prepubertal (11.9 +/- 0.3 years; Tanner Stages 1-2) and 14 pubertal (14.3 +/- 1.4 years; Tanner Stages 3-4) boys participated in the study. The energy cost of swimming (Cs) and stroking parameters were assessed over maximal 400-m front-crawl swimming in a 25-m swimming pool. The backward extrapolation technique was used to evaluate peak oxygen consumption (VO2peak). A stroke index (SI; m2 . s(-1) . cycles(-1)) was calculated by multiplying the swimming speed by the stroke length. VO2peak results were compared with VO2peak test in the laboratory (bicycle, 2.86 +/- 0.74 L/min, vs. in water, 2.53 +/- 0.50 L/min; R2 = .713; p = .0001). Stepwise-regression analyses revealed that SI (R2 = .898), in-water VO2peak (R2 = .358), and arm span (R2 = .454) were the best predictors of swimming performance. The backward-extrapolation method could be used to assess VO2peak in young swimmers. SI, arm span, and VO2peak appear to be the major determinants of front-crawl swimming performance in young swimmers.

  20. Daily physical activity and its relation to aerobic fitness in children aged 8-11 years

    DEFF Research Database (Denmark)

    Dencker, Magnus; Thorsson, Ola; Karlsson, Magnus K.

    2006-01-01

    and fitness in children has been published, where fitness has been assessed by direct measurement of maximum oxygen uptake and related to daily physical activity intensities by accelerometers. We examined 248 children (140 boys and 108 girls), aged 7.9-11.1 years. Maximum workload and maximal oxygen uptake...... in vigorous physical activity were calculated. VO2PEAK was correlated with mean accelerometer counts (r=0.23 for boys and r=0.23 for girls, both Pactivity (r=0.32 for boys, r=0.30 for girls, both P...Abstract  A positive relationship between daily physical activity and aerobic fitness exists in adults. Studies in children have given conflicting results, possibly because of differences in methods used to assess daily physical activity and fitness. No study regarding daily physical activity...

  1. Uptake of crude petroleum hydrocarbons by mudflat bacteria ...

    African Journals Online (AJOL)

    SERVER

    2007-08-06

    Aug 6, 2007 ... bacteria exposed to nitrogenous fertilizer plant ... accompanied by a rapid decline in the level of crude petroleum in the amended .... conductivity, turbidity, salinity, dissolved oxygen (fresh sample only) ... Nutrient uptake was.

  2. 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.

  3. Oxygen Deficit: The Bio-energetic Pathophysiology

    Directory of Open Access Journals (Sweden)

    ABHAY KUMAR PANDEY

    2014-09-01

    Full Text Available Scarcity of oxygen in humans arises via three modes. The environment may have low oxygen to breath. There can be disease in respiratory system causing hindrance to uptake of oxygen from environment and the circulatory system may be sluggish to supply to body parts that starve for oxygen. Thirdly the chemico-cellular components of blood which carry oxygen may be lowered or defective. In reference to body cells several limiting sites and mechanisms affect the amount of oxygen delivered to them, and these are under regulatory control of several functional and metabolic systems.

  4. Intensive lifestyle intervention improves cardiometabolic and exercise parameters in metabolically healthy obese and metabolically unhealthy obese individuals.

    Science.gov (United States)

    Dalzill, Claudie; Nigam, Anil; Juneau, Martin; Guilbeault, Valérie; Latour, Elise; Mauriège, Pascale; Gayda, Mathieu

    2014-04-01

    The effects of an intensive lifestyle intervention including Mediterranean diet nutritional counselling and high-intensity interval training (HIIT) on body composition, cardiometabolic, and exercise parameters were studied in metabolically unhealthy obese (NMHO) and metabolically healthy but obese (MHO) subjects. Fifty-five MHO (51 ± 8 years; waist circumference, 109 ± 13 cm) and 79 NMHO subjects (54 ± 9 years; waist circumference, 112 ± 13 cm) participated in an intensive lifestyle modification program based on Mediterranean diet nutritional counselling and HIIT 2-3 times per week. Body composition, cardiometabolic, and exercise parameters were measured at baseline and after 9 months. Initially, MHO patients had a lower blood pressure (BP), fasting glycemia, triglycerides, and a higher high-density lipoprotein cholesterol and peak oxygen uptake (VO2 peak) (P lifestyle program including Mediterranean diet nutritional counselling and HIIT is an appropriate intervention in MHO and NMHO subjects with similar potential clinical health benefits including an improved body composition, BP, fasting glycemia, insulin sensitivity, VO2 peak, and muscle endurance. Copyright © 2014 Canadian Cardiovascular Society. All rights reserved.

  5. Cardiorespiratory Fitness is a Strong Predictor of the Cardio-ankle Vascular Index in Hypertensive Middle-aged and Elderly Japanese Men.

    Science.gov (United States)

    Tanisawa, Kumpei; Ito, Tomoko; Sun, Xiaomin; Kawakami, Ryoko; Oshima, Satomi; Gando, Yuko; Cao, Zhen-Bo; Sakamoto, Shizuo; Higuchi, Mitsuru

    2015-01-01

    This study aimed to examine whether cardiorespiratory fitness (CRF) is associated with arterial stiffening, evaluated using the cardio-ankle vascular index (CAVI), independent of visceral fat (VF) in middle-aged and elderly Japanese men. We also examined whether the relationship between CRF and the CAVI is modified by age and/or hypertension. The CAVI was determined in 157 Japanese men (age range, 30-79 years), including 96 hypertensive subjects (61.1%). CRF was assessed by measuring the peak oxygen uptake (VO2peak). The subjects were divided into low- and high-CRF groups, and the VF area was assessed using magnetic resonance imaging. The VO2peak correlated with the CAVI following adjustment for age and body mass index in the middle-aged and elderly groups (all the subjects: r=-0.285, p<0.001; middle-aged: r=-0.240, p=0.040; elderly: r=-0.225, p=0.049). VF also correlated with the CAVI (r=0.230, p=0.004). A multiple linear regression analysis revealed that age (β=0.406, pmen.

  6. A non-exercise prediction model for estimation of cardiorespiratory fitness in adults. DOI: http://dx.doi.org/10.5007/1980-0037.2012v14n3p287

    Directory of Open Access Journals (Sweden)

    Magnus Benetti

    2012-05-01

    Full Text Available The most accurate tool for assessment of cardiorespiratory fitness is cardiopulmonary exercise testing (CPET. However, CPET requires expensive equipment, trained technicians and time, which limits their use in population studies. In view of this issue, the present study aims to develop regression equations for predicting the cardiorespiratory fitness of adults using simple measurement variables. The study used data from 8,293 subjects, 5,291 male and 3,235 female (age range, 18 to 65 years. The sample was recruited in Florianopolis, Santa Catarina. To develop equations for prediction of peak oxygen uptake (VO2peak, the data associated were: fitness, age, body mass, height, resting heart rate, hypertension, diabetes, dyslipidemia and smoking. After statistical analyses, two equations for men and two for women were developed. The complete equations showed an adjusted R2 = 0.531 and a standard error of estimate (SEE = 7.15 ml-1∙kg-1∙min for men and R2 = 0.436 and SEE = 5.68 ml-1∙kg-1∙min for women. We conclude that the model developed for prediction of cardiorespiratory fitness is feasible and practical for prediction of VO2peak in epidemiological studies or when CPET cannot be performed.

  7. Cardiorespiratory and cardiac autonomic responses to 30-15 intermittent fitness test in team sport players.

    Science.gov (United States)

    Buchheit, Martin; Al Haddad, Hani; Millet, Grégoire Paul; Lepretre, Pierre Marie; Newton, Michael; Ahmaidi, Said

    2009-01-01

    The 30-15 Intermittent Fitness Test (30-15IFT) is an attractive alternative to classic continuous incremental field tests for defining a reference velocity for interval training prescription in team sport athletes. The aim of the present study was to compare cardiorespiratory and autonomic responses to 30-15IFT with those observed during a standard continuous test (CT). In 20 team sport players (20.9 +/- 2.2 years), cardiopulmonary parameters were measured during exercise and for 10 minutes after both tests. Final running velocity, peak lactate ([La]peak), and rating of perceived exertion (RPE) were also measured. Parasympathetic function was assessed during the postexercise recovery phase via heart rate (HR) recovery time constant (HRR[tau]) and HR variability (HRV) vagal-related indices. At exhaustion, no difference was observed in peak oxygen uptake VO2peak), respiratory exchange ratio, HR, or RPE between 30-15IFT and CT. In contrast, 30-15IFT led to significantly higher minute ventilation, [La]peak, and final velocity than CT (p HRV vagal-related indices (i.e., the root mean square of successive R-R intervals differences [rMSSD]: 4.1 +/- 2.4 and 7.0 +/- 4.9 milliseconds, p < 0.05). In conclusion, the 30-15IFT is accurate for assessing VThs and VO2peak, but it alters postexercise parasympathetic function more than a continuous incremental protocol.

  8. Effects of adjunctive exercise on physiological and psychological parameters in depression: a randomized pilot trial.

    Science.gov (United States)

    Kerling, Arno; Tegtbur, Uwe; Gützlaff, Elke; Kück, Momme; Borchert, Luise; Ates, Zeynep; von Bohlen, Anne; Frieling, Helge; Hüper, Katja; Hartung, Dagmar; Schweiger, Ulrich; Kahl, Kai G

    2015-05-15

    Major depressive disorder (MDD) is associated with decreased physical activity and increased rates of the metabolic syndrome (MetS), a risk factor for the development of type 2 diabetes and cardiovascular disorders. Exercise training has been shown to improve cardiorespiratory fitness and metabolic syndrome factors. Therefore, our study aimed at examining whether patients receiving an exercise program as an adjunct to inpatient treatment will benefit in terms of physiological and psychological factors. Fourty-two inpatients with moderate to severe depression were included. Twenty-two patients were randomized to additional 3x weekly exercise training (EXERCISE) and compared to treatment as usual (TAU). Exercise capacity was assessed as peak oxygen uptake (VO2peak), ventilatory anaerobic threshold (VAT) and workload expressed as Watts (W). Metabolic syndrome was defined according to NCEP ATPIII panel criteria. After 6 weeks of treatment, cardiorespiratory fitness (VO2peak, VAT, Watt), waist circumference and HDL cholesterol were significantly improved in EXERCISE participants. Treatment response expressed as ≥50% MADRS reduction was more frequent in the EXERCISE group. Adjunctive exercise training in depressed inpatients improves physical fitness, MetS factors, and psychological outcome. Given the association of depression with cardiometablic disorders, exercise training is recommended as an adjunct to standard antidepressant treatment. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Short-term moderate intensive high volume training program provides aerobic endurance benefit in wheelchair basketball players.

    Science.gov (United States)

    Skucas, Kestutis; Pokvytyte, Vaida

    2017-04-01

    The aim of this paper was to investigate the effect of short-term period, moderate intensity and high volume endurance training on physiological variables in elite wheelchair basketball players. Eight wheelchair basketball players were examined. The subjects participated in a two-week intervention program of mainly two training types: wheelchair basketball and wheelchair driving endurance training. The subjects performed the continuously increasing cycling exercise (CCE) at the constant 60 rpm arm cranking speed at the beginning of the program and after two weeks of the program. The initial workload was 20 W, then the workload was increased by 2 W every 5 seconds until fatigue. The post training of the wheelchair basketball group in the study showed a significant improvement in the peak oxygen uptake (VO2peak) and the peak power output (POpeak). VO2peak increased by 9% from 2.32±0.16 L/min to 2.53±0.2 L/min (Pbasketball squad had relatively high levels of aerobic fitness prior to participating in the endurance training program. Nevertheless, the high-volume, moderate-intensity, short-term training program, which evolved over the two-weeks period, resulted in the improvement of the athlete's aerobic endurance. The ventilatory threshold (VT) and the second ventilatory threshold (VT2) are good markers for aerobic capacity of wheelchair athletes.

  10. Short-term cardiorespiratory adaptation to high altitude in children compared with adults.

    Science.gov (United States)

    Kriemler, S; Radtke, T; Bürgi, F; Lambrecht, J; Zehnder, M; Brunner-La Rocca, H P

    2016-02-01

    As short-term cardiorespiratory adaptation to high altitude (HA) exposure has not yet been studied in children, we assessed acute mountain sickness (AMS), hypoxic ventilatory response (HVR) at rest and maximal exercise capacity (CPET) at low altitude (LA) and HA in pre-pubertal children and their fathers. Twenty father-child pairs (11 ± 1 years and 44 ± 4 years) were tested at LA (450 m) and HA (3450 m) at days 1, 2, and 3 after fast ascent (HA1/2/3). HVR was measured at rest and CPET was performed on a cycle ergometer. AMS severity was mild to moderate with no differences between generations. HVR was higher in children than adults at LA and increased at HA similarly in both groups. Peak oxygen uptake (VO2 peak) relative to body weight was similar in children and adults at LA and decreased significantly by 20% in both groups at HA; maximal heart rate did not change at HA in children while it decreased by 16% in adults (P < 0.001). Changes in HVR and VO2 peak from LA to HA were correlated among the biological child-father pairs. In conclusion, cardiorespiratory adaptation to altitude seems to be at least partly hereditary. Even though children and their fathers lose similar fractions of aerobic capacity going to high altitude, the mechanisms might be different. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. Isometric strength training lowers the O2 cost of cycling during moderate-intensity exercise.

    Science.gov (United States)

    Zoladz, Jerzy A; Szkutnik, Zbigniew; Majerczak, Joanna; Grandys, Marcin; Duda, Krzysztof; Grassi, Bruno

    2012-12-01

    The effect of maximal voluntary isometric strength training of knee extensor muscles on pulmonary V'O(2) on-kinetics, the O(2) cost of cycling and peak oxygen uptake (V'O(2peak)) in humans was studied. Seven healthy males (mean ± SD, age 22.3 ± 2.0 years, body weight 75.0 ± 9.2 kg, V'O(2peak) 49.5 ± 3.8 ml kg(-1) min(-1)) performed maximal isometric strength training lasting 7 weeks (4 sessions per week). Force during maximal voluntary contraction (MVC) increased by 15 % (P Strength training resulted in a significant decrease (by ~7 %; P Isometric strength training rapidly (i.e., after 1 week) decreases the O(2) cost of cycling during moderate-intensity exercise, whereas it does not affect the amplitude of the slow component of the V'O(2) on-kinetics during heavy-intensity exercise. Isometric strength training can have beneficial effects on performance during endurance events.

  12. Prolonged static stretching does not influence running economy despite changes in neuromuscular function.

    Science.gov (United States)

    Allison, Sarah J; Bailey, David M; Folland, Jonathan P

    2008-12-01

    The aim of this study was to examine the acute effects of prolonged static stretching (SS) on running economy. Ten male runners (VO2(peak) 60.1 +/- 7.3 ml x kg(-1) x min(-1)) performed 10 min of treadmill running at 70% VO2(peak) before and after SS and no stretching interventions. For the stretching intervention, each leg was stretched unilaterally for 40 s with each of eight different exercises and this was repeated three times. Respiratory gas exchange was measured throughout the running exercise with an automated gas analysis system. On a separate day, participants were tested for sit and reach range of motion, isometric strength and countermovement jump height before and after SS. The oxygen uptake, minute ventilation, energy expenditure, respiratory exchange ratio and heart rate responses to running were unaffected by the stretching intervention. This was despite a significant effect of SS on neuromuscular function (sit and reach range of motion, +2.7 +/- 0.6 cm; isometric strength, -5.6% +/- 3.4%; countermovement jump height -5.5% +/- 3.4%; all P influence running economy despite changes in neuromuscular function.

  13. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... for a thyroid scan is 30 minutes or less. Thyroid Uptake You will be given radioactive iodine ( ... for each thyroid uptake is five minutes or less. top of page What will I experience during ...

  14. Thyroid Scan and Uptake

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    Full Text Available ... uptake measurements are obtained at different times. For example, you may have uptake measurements at four to ... medicine procedures can be time consuming. It can take several hours to days for the radiotracer to ...

  15. Thyroid Scan and Uptake

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    Full Text Available ... Scan and Uptake Thyroid scan and uptake uses small amounts of radioactive materials called radiotracers, a special ... is a branch of medical imaging that uses small amounts of radioactive material to diagnose and determine ...

  16. Thyroid Scan and Uptake

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    Full Text Available ... radioactive iodine uptake test (RAIU) is also known as a thyroid uptake. It is a measurement of ... potential to identify disease in its earliest stages as well as a patient’s immediate response to therapeutic ...

  17. Thyroid Scan and Uptake

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    Full Text Available ... known as a thyroid uptake. It is a measurement of thyroid function, but does not involve imaging. ... eating can affect the accuracy of the uptake measurement. Jewelry and other metallic accessories should be left ...

  18. Thyroid Scan and Uptake

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    Full Text Available ... Uptake? A thyroid scan is a type of nuclear medicine imaging. The radioactive iodine uptake test (RAIU) ... of thyroid function, but does not involve imaging. Nuclear medicine is a branch of medical imaging that ...

  19. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... for a thyroid scan is 30 minutes or less. Thyroid Uptake You will be given radioactive iodine (I-123 or I-131) in liquid or capsule form to swallow. The thyroid uptake will begin several hours to 24 hours later. Often, two separate uptake ...

  20. 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.

  1. 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 ...

  2. 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.

  3. Feedback-controlled robotics-assisted treadmill exercise to assess and influence aerobic capacity early after stroke: a proof-of-concept study.

    Science.gov (United States)

    Stoller, Oliver; Schindelholz, Matthias; Bichsel, Lukas; Schuster, Corina; de Bie, Rob A; de Bruin, Eling D; Hunt, Kenneth J

    2014-07-01

    The majority of post-stroke individuals suffer from low exercise capacity as a secondary reaction to immobility. The aim of this study was to prove the concept of feedback-controlled robotics-assisted treadmill exercise (RATE) to assess aerobic capacity and guide cardiovascular exercise in severely impaired individuals early after stroke. Subjects underwent constant load and incremental exercise testing using a human-in-the-loop feedback system within a robotics-assisted exoskeleton (Lokomat, Hocoma AG, CH). Inclusion criteria were: stroke onset ≤8 weeks, stable medical condition, non-ambulatory status, moderate motor control of the lower limbs and appropriate cognitive function. Outcome measures included oxygen uptake kinetics, peak oxygen uptake (VO2peak), gas exchange threshold (GET), peak heart rate (HRpeak), peak work rate (Ppeak) and accuracy of reaching target work rate (P-RMSE). Three subjects (18-42 d post-stroke) were included. Oxygen uptake kinetics during constant load ranged from 42.0 to 60.2 s. Incremental exercise testing showed: VO2peak range 19.7-28.8 ml/min/kg, GET range 11.6-12.7 ml/min/kg, and HRpeak range 115-161 bpm. Ppeak range was 55.2-110.9 W and P-RMSE range was 3.8-7.5 W. The concept of feedback-controlled RATE for assessment of aerobic capacity and guidance of cardiovascular exercise is feasible. Further research is warranted to validate the method on a larger scale. Aerobic capacity is seriously reduced in post-stroke individuals as a secondary reaction to immobility. Robotics-assisted walking devices may have substantial clinical relevance regarding assessment and improvement of aerobic capacity early after stroke. Feedback-controlled robotics-assisted treadmill exercise represents a new concept for cardiovascular assessment and intervention protocols for severely impaired individuals.

  4. 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.

  5. Thyroid uptake test

    International Nuclear Information System (INIS)

    Ganatra, R.D.

    1992-01-01

    The uptake of radioiodine by the thyroid gland is altered by the iodine content of diet or drugs. American diet has a high iodine content because each slice of the white bread contains nearly 150μg of iodine due to the bleaching process employed in the production of the bread. This carrier content of iodine reduces the uptake so much, that the normal American uptakes are usually three to four times lower than the uptakes in the developing countries. The other drawback of the thyroid uptake test is that it is affected by the iodine containing drugs. Anti-diarrhoea medications are quire common in the developing countries and many of them contain iodine moiety. Without a reliable drug history, a low thyroid uptake value may lead to a misleading conclusion

  6. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... of nuclear medicine imaging. The radioactive iodine uptake test (RAIU) is also known as a thyroid uptake. ...

  7. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Thyroid Scan and Uptake Thyroid scan and uptake uses ...

  8. Effects of High-Intensity Interval Training versus Continuous Training on Physical Fitness, Cardiovascular Function and Quality of Life in Heart Failure Patients.

    Directory of Open Access Journals (Sweden)

    Nathalie M M Benda

    Full Text Available Physical fitness is an important prognostic factor in heart failure (HF. To improve fitness, different types of exercise have been explored, with recent focus on high-intensity interval training (HIT. We comprehensively compared effects of HIT versus continuous training (CT in HF patients NYHA II-III on physical fitness, cardiovascular function and structure, and quality of life, and hypothesize that HIT leads to superior improvements compared to CT.Twenty HF patients (male:female 19:1, 64±8 yrs, ejection fraction 38±6% were allocated to 12-weeks of HIT (10*1-minute at 90% maximal workload-alternated by 2.5 minutes at 30% maximal workload or CT (30 minutes at 60-75% of maximal workload. Before and after intervention, we examined physical fitness (incremental cycling test, cardiac function and structure (echocardiography, vascular function and structure (ultrasound and quality of life (SF-36, Minnesota living with HF questionnaire (MLHFQ.Training improved maximal workload, peak oxygen uptake (VO2peak related to the predicted VO2peak, oxygen uptake at the anaerobic threshold, and maximal oxygen pulse (all P<0.05, whilst no differences were present between HIT and CT (N.S.. We found no major changes in resting cardiovascular function and structure. SF-36 physical function score improved after training (P<0.05, whilst SF-36 total score and MLHFQ did not change after training (N.S..Training induced significant improvements in parameters of physical fitness, although no evidence for superiority of HIT over CT was demonstrated. No major effect of training was found on cardiovascular structure and function or quality of life in HF patients NYHA II-III.Nederlands Trial Register NTR3671.

  9. Consumo máximo de oxigênio e limiar anaeróbio de jogadores de futebol: comparação entre as diferentes posições Maximal oxygen uptake and anaerobic threshold in professional soccer players: comparison between different positions

    Directory of Open Access Journals (Sweden)

    Pedro Balikian

    2002-04-01

    Full Text Available O grau de desenvolvimento das capacidades físicas no futebol é fator determinante do nível desportivo do jogador. O objetivo do presente estudo foi comparar valores de limiar anaeróbio e consumo máximo de oxigênio entre jogadores profissionais de futebol de diferentes posições. Para tanto, 25 atletas (idade = 22,08 ± 8,28 anos, peso = 76,12 ± 9,8kg, altura = 179,8 ± 7,1cm e relação corporal = 12,21 ± 3,67% de gordura corporal foram divididos em cinco grupos, como se segue: goleiros (GO, zagueiros (ZA, laterais (LA, meio-campistas (MC e atacantes (AT. O VO2max foi determinado em esteira ergométrica através de análise direta e a velocidade de corrida correspondente ao limiar anaeróbio fixo de 4mM (V4mM, em teste de campo (2 x 1.000m a 90 e 95% da velocidade máxima para a distância através de interpolação linear. A V4mM foi menor (p The development of physical capacities in soccer determines the player's level of performance. The aim of this study was to compare anaerobic threshold and maximal oxygen uptake values between professional soccer players playing in different positions. Twenty-five male athletes (age = 22.08 ± 8.82 years, weight = 76.12 ± 9.8 kg, height = 179.8 ± 7.1 cm and body composition = 12.21 ± 3.67% body fat were divided into five groups as follows: goalkeepers (GO, full backs (FB, sideways (SW, midfield (MF and forwards (FO and evaluated twice in two to three days period. For direct maximal oxygen uptake (VO2max determination, subjects were submitted to an incremental continuous treadmill exercise until fatigue occurred. Two-speeds track test (2 x 1,000 m at 90 and 95% of maximal speed and linear interpolation were employed for 4mM blood lactate running speed (V4mM or anaerobic threshold assessment. Main results are present below. V4mM for GO group was significantly lower (p 0.05 from one another. Since these athletes were under the same training program, the differences above may be explained by

  10. Effect of moderate- versus high-intensity exercise on vascular function, biomarkers and quality of life in heart transplant recipients

    DEFF Research Database (Denmark)

    Dall, Christian H; Gustafsson, Finn; Christensen, Stefan B

    2015-01-01

    BACKGROUND: Growing evidence in long-term treatment of heart transplant (HTx) recipients indicates effects of high-intensity interval training (HIIT) on several parameters, including oxygen uptake, vascular function and psychological distress. In this study we compare the effect of HIIT vs...... continued moderate training (CON) on vascular function, biomarkers and health-related quality of life (HRQoL) in HTx recipients. METHODS: A randomized, controlled crossover trial of stable HTx recipients >12 months after transplantation was done on patients with 12 weeks of HIIT or 12 weeks of CON, followed...... by a 5-month washout and crossover. Outcomes included endothelial function, arterial stiffness, biomarkers, HRQoL and markers of anxiety and depression. RESULTS: Sixteen HTx recipients (mean age 52 years, 75% male) completed the study. HIIT increased VO2peak more than CON (between-group difference, p

  11. Hollow Nanospheres with Fluorous Interiors for Transport of Molecular Oxygen in Water

    KAUST Repository

    Vu, Khanh B.; Chen, Tianyou; Almahdali, Sarah; Bukhriakov, Konstantin; Rodionov, Valentin

    2016-01-01

    are gas-permeable and feature reactive functional groups for easy modification of the exterior. These features make the SFC-filled nanospheres promising vehicles for respiratory oxygen storage and transport. Uptake of molecular oxygen into nanosphere

  12. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... information about your thyroid’s size, shape, position and function that is often unattainable using other imaging procedures. ... thyroid uptake. It is a measurement of thyroid function, but does not involve imaging. Nuclear medicine is ...

  13. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... which are encased in metal and plastic and most often shaped like a box, attached to a ... will I experience during and after the procedure? Most thyroid scan and thyroid uptake procedures are painless. ...

  14. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... eat for several hours before your exam because eating can affect the accuracy of the uptake measurement. ... often unattainable using other imaging procedures. For many diseases, nuclear medicine scans yield the most useful information ...

  15. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... A thyroid scan is a type of nuclear medicine imaging. The radioactive iodine uptake test (RAIU) is ... thyroid function, but does not involve imaging. Nuclear medicine is a branch of medical imaging that uses ...

  16. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... Because nuclear medicine procedures are able to pinpoint molecular activity within the body, they offer the potential ... or imaging device that produces pictures and provides molecular information. The thyroid scan and thyroid uptake provide ...

  17. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... Actual scanning time for each thyroid uptake is five minutes or less. top of page What will ... diagnostic procedures have been used for more than five decades, and there are no known long-term ...

  18. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... top of page Additional Information and Resources RTAnswers.org Radiation Therapy for Head and Neck Cancer top ... Scan and Uptake Sponsored by Please note RadiologyInfo.org is not a medical facility. Please contact your ...

  19. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... When radiotracer is taken by mouth, in either liquid or capsule form, it is typically swallowed up ... radioactive iodine (I-123 or I-131) in liquid or capsule form to swallow. The thyroid uptake ...

  20. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... RAIU) is also known as a thyroid uptake. It is a measurement of thyroid function, but does ... they offer the potential to identify disease in its earliest stages as well as a patient’s immediate ...

  1. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... for several hours before your exam because eating can affect the accuracy of the uptake measurement. Jewelry ... small hand-held device resembling a microphone that can detect and measure the amount of the radiotracer ...

  2. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... of page What will I experience during and after the procedure? Most thyroid scan and thyroid uptake ... you otherwise, you may resume your normal activities after your nuclear medicine scan. If any special instructions ...

  3. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... scan and thyroid uptake provide information about the structure and function of the thyroid. The thyroid is ... computer, create pictures offering details on both the structure and function of organs and tissues in your ...

  4. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... eat for several hours before your exam because eating can affect the accuracy of the uptake measurement. ... its radioactivity over time. It may also pass out of your body through your urine or stool ...

  5. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... procedures within the last two months that used iodine-based contrast material. Your doctor will instruct you ... a type of nuclear medicine imaging. The radioactive iodine uptake test (RAIU) is also known as a ...

  6. Physical training in children with osteogenesis imperfecta.

    Science.gov (United States)

    Van Brussel, Marco; Takken, Tim; Uiterwaal, Cuno S P M; Pruijs, Hans J; Van der Net, Janjaap; Helders, Paul J M; Engelbert, Raoul H H

    2008-01-01

    To study the effects of a physical training program on exercise capacity, muscle force, and subjective fatigue levels in patients with mild to moderate forms of osteogenesis imperfecta (OI). Thirty-four children with OI type I or IV were randomly assigned to either a 12-week graded exercise program or care as usual for 3 months. Exercise capacity and muscle force were studied; subjective fatigue, perceived competence, and health-related quality of life were secondary outcomes. All outcomes were measured at baseline (T = 0), after intervention (T = 1), and after 6 and 9 months (T = 2 and T = 3, respectively). After intervention (T = 1), peak oxygen consumption (VO2peak), relative VO2peak (VO2peak/kg), maximal working capacity (Wmax), and muscle force were significantly improved (17%, 18%, 10%, and 12%, respectively) compared with control values. Subjective fatigue decreased borderline statistically significantly. Follow-up at T = 2 showed a significant decrease of the improvements measured at T = 1 of VO2peak, but VO2peak/kg, Wmax, and subjective fatigue showed no significant difference. At T = 3, we found a further decrease of the gained improvements. A supervised training program can improve aerobic capacity and muscle force and reduces levels of subjective fatigue in children with OI type I and IV in a safe and effective manner.

  7. Oxidation and microstrucure of V-Cr-Ti alloys exposed to oxygen-containing environments

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K. [Argonne National Lab., IL (United States); Uz, M. [Lafayette College, Easton, PA (United States); Ulie, T.

    1997-08-01

    The objectives of this task are to (a) evaluate the oxygen uptake of several V-Cr-Ti alloys as a function of temperature and oxygen partial pressure in the exposure environment, (b) examine the microstructural characteristics of oxide scales and oxygen trapped at the grain boundaries in the substrate alloys, and (c) evaluate the influence of alloy composition on oxygen uptake and develop correlation(s) between alloy composition, exposure environment, and temperature.

  8. 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....

  9. Oxidation and microstrucure of V-Cr-Ti alloys exposed to oxygen-containing environments

    International Nuclear Information System (INIS)

    Natesan, K.; Uz, M.; Ulie, T.

    1997-01-01

    The objectives of this task are to (a) evaluate the oxygen uptake of several V-Cr-Ti alloys as a function of temperature and oxygen partial pressure in the exposure environment, (b) examine the microstructural characteristics of oxide scales and oxygen trapped at the grain boundaries in the substrate alloys, and (c) evaluate the influence of alloy composition on oxygen uptake and develop correlation(s) between alloy composition, exposure environment, and temperature

  10. Regular Aerobic Training Combined with Range of Motion Exercises in Juvenile Idiopathic Arthritis

    Directory of Open Access Journals (Sweden)

    Mine Doğru Apti

    2014-01-01

    Full Text Available Objective. To assess the effects of regular aerobic training combined with range of motion (ROM exercises on aerobic capacity, quality of life, and function in children with juvenile idiopathic arthritis (JIA. Methods. Thirty patients with JIA and 20 healthy age-matched controls (mean age ± SD, 11.3 ± 2.4 versus 11.0 ± 2.3, resp.; P>0.05 were included. All patients performed aerobic walking (4 days a week for 8 weeks and active and passive ROM exercises of involved joints. All patients completed the childhood health assessment questionnaire (CHAQ and the child health questionnaire. ROM measurements of joints were performed by using universal goniometer. Aerobic capacity was determined by measuring peak oxygen uptake (VO2peak during an incremental treadmill test. Results. Peak oxygen uptake and exercise duration were significantly lower in JIA group than in controls (32.5 ± 6.6 versus 35.9 ± 5.8 and 13.9 ± 1.9 versus 15.0 ± 2.0, resp.; P<0.05 for both. Eight-week combined exercise program significantly improved exercise parameters of JIA patients (baseline versus postexercise VO2peak and exercise duration, 32.5 ± 6.6 to 35.3 ± 7.9 and 13.9 ± 1.9 to 16.3 ± 2.2, resp.; P<0.001 for both. Exercise intervention significantly improved CHAQ scores in JIA patients (0.77 ± 0.61 to 0.20 ± 0.28, P<0.001. Conclusion. We suggest that regular aerobic exercise combined with ROM exercises may be an important part of treatment in patients with JIA.

  11. Comparison of Aerobic Performance Testing Protocols in Elite Male Wheelchair Basketball Players

    Directory of Open Access Journals (Sweden)

    Molik Bartosz

    2017-12-01

    Full Text Available In wheelchair sports, aerobic performance is commonly assessed with the use of an arm crank ergometer (ACE, a wheelchair ergometer (WCE or a wheelchair treadmill (WCT. There are different protocols to identify peak oxygen uptake in wheelchair sports; however, only a few protocols have been applied to evaluate these conditions in wheelchair basketball players. The purpose of this study was to compare physiological responses during maximal exercise testing with the use of ACE and WCT in wheelchair basketball players. Twelve elite male wheelchair basketball players participated in this study. The research was performed during a training camp of the Polish National Wheelchair Basketball Team. The study participants were divided into two functional categories: A (players with class 1.0 - 2.5 and B (players with class 3.0 - 4.5. Two main maximal exercise tests, i.e. wheelchair treadmill stress test (WCT test and arm crank ergometer stress test (ACE test were used to evaluate aerobic performance of the players. There were no statistically significant differences in aerobic tests between the players from both groups. The comparison of results achieved in two aerobic tests performed on WCT and ACE did not reveal any significant differences between the analyzed variables (peak heart rate (HRpeak, peak oxygen uptake (VO2peak, minute ventilation (VE, anaerobic threshold (AT, lactate concentration (LApeak, and a drop in lactate concentration (%LA. Strong correlations between results achieved in WCT and ACE tests were found for VO2peak, VE and LApeak. The main conclusion of the study is that both WCT and ACE tests may be useful when determining aerobic capacity of wheelchair basketball players. Moreover, both protocols can be used by athletes regardless of their functional capabilities and types of impairment.

  12. The impact of acute bouts of interval and continuous walking on energy-intake and appetite regulation in subjects with type 2 diabetes

    DEFF Research Database (Denmark)

    Müller, Ida A; Wedell-Neergaard, Anne-Sophie; Solomon, Thomas P J

    2017-01-01

    In healthy subjects, it has been suggested that exercise may acutely suppress energy-intake and appetite, with peak intensity being an important determinant for this effect. In subjects with type 2 diabetes (T2D), the effect of exercise on appetite-related variables is, however, virtually unknown....... We aimed to assess the effects of two exercise interventions, differing with regards to peak intensity, on energy-intake, satiety and appetite-related hormones in subjects with T2D. Thirteen subjects with T2D completed three 60-min interventions with continuous measurement of oxygen consumption...... in a randomized and counterbalanced order: (1) Control, (2) Continuous walking (CW; intended 73% of VO2peak), (3) Interval-walking (IW; repeated cycles of 3 min slow [54% of VO2peak] and 3 min fast walking [89% of VO2peak]). Forty-five minutes after completion of the intervention, a 3-h liquid mixed meal...

  13. 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 ...

  14. 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 ...

  15. Thyroid uptake software

    International Nuclear Information System (INIS)

    Alonso, Dolores; Arista, Eduardo

    2003-01-01

    The DETEC-PC software was developed as a complement to a measurement system (hardware) able to perform Iodine Thyroid Uptake studies. The software was designed according to the principles of Object oriented programming using C++ language. The software automatically fixes spectrometric measurement parameters and besides patient measurement also performs statistical analysis of a batch of samples. It possesses a PARADOX database with all information of measured patients and a help system with the system options and medical concepts related to the thyroid uptake study

  16. Work capacity and oxygen uptake abnormalities in hyperthyroidism.

    Science.gov (United States)

    Irace, L; Pergola, V; Di Salvo, G; Perna, B; Tedesco, M A; Ricci, C; Tuccillo, B; Iacono, A

    2006-06-01

    The aim of our study was to evaluate the haemodynamic and the respiratory response to exercise in patients with hyperthyroidism before and 30 days after normalized thyroid hormones levels. These findings were compared with those of 10 control patients. Thirty patients (23 women, aged 34.3 +/- 12 years) with untreated hyperthyroidism were studied. Twenty-four patients were treated with methimazole, 13 of which were also treated with propranolol. Six patients underwent surgery. A symptom-limited cardiopulmonary exercise test and an echocardiography were performed in all patients. At rest patients with hyperthyroidism showed at echocardiography an increased cardiac index (P = 0.006 vs euthyroid, P = 0.007 vs normal) and a higher ejection fraction (P = 0.008 vs euthyroid, P = 0.007 vs normal). The duration of the exercise was lower in hyperthyroid patients (P = 0.006 vs euthyroid; P = 0.0068 vs normal). Anaerobic threshold was reached at 49.6% of peak VO2 during hyperthyroidism, at 60.8% during euthyroidism (P = 0.01) and at 62% in normal (P = 0.01). Work rate was lower in patients with hyperthyroidism at anaerobic threshold (P = 0.01 vs euthyroid, P = 0.03 vs normal) and at maximal work (P = 0.001 vs euthyroid, P = 0.01 vs normal). Patients in hyperthyroidism showed a lower increment of heart rate between rest and anaerobic threshold (P = 0.021 vs euthyroid, P hyperthyroidism (P = 0.04 vs euthyroid, P = 0.005 vs normal). The mean result is that after only 30 days of appropriate antithyroid treatment there was an appreciable improvement of exertion capacity.

  17. Empirical Modeling of Oxygen Uptake of Flow Over Stepped Chutes ...

    African Journals Online (AJOL)

    The present investigation evaluates the influence of three different step chute geometry when skimming flow was allowed over them with the aim of determining the aerated flow length which is a significant factor when developing empirical equations for estimating aeration efficiency of flow. Overall, forty experiments were ...

  18. Oxygen uptake kinetics Of Pseudomonas sp. strain VB grown under ...

    African Journals Online (AJOL)

    Fred

    2004-07-22

    Jul 22, 2004 ... 1996). Its diverse uses makes the substance ubiquitous as an environmental xenobiotic which has considerable implications within the global biosphere. The microbial mixed cultural degradation of 2- methoxyethanol under anaerobic conditions has been reported (Tanaka et al., 1986; Tanaka and Pfennig,.

  19. Impact of training status on maximal oxygen uptake criteria ...

    African Journals Online (AJOL)

    Peak treadmill running speed was significantly faster and total test time significantly longer in the trained group. In contrast, peak lactate, although maximal for both groups, was significantly higher in the untrained group (13.5 mmol.l-1 compared with 10.3 mmol.l-1). The other responses were not different between the groups ...

  20. Efeitos do treinamento de resistência de força com alto número de repetições no consumo máximo de oxigênio e limiar ventilatório de mulheres Effects of strength resistance training with high number of repetitions on maximal oxygen uptake and ventilatory threshold in women

    Directory of Open Access Journals (Sweden)

    Thiago Mattos Frota de Souza

    2008-12-01

    Full Text Available Os efeitos do treinamento com pesos na aptidão cardiorrespiratória de mulheres não estão amplamente definidos. O estudo teve como objetivo investigar os efeitos do treinamento de resistência de força com alto número de repetições no consumo máximo de oxigênio e limiar ventilatório em mulheres jovens. Participaram deste estudo 20 mulheres, com idade de 21,2 ± 2,7 anos, agrupadas em: I - grupo de treinamento de resistência de força com alto número de repetições (GT, n = 10 e II - controle (GC, n = 10. Todas as voluntárias foram submetidas ao seguinte protocolo: antropometria, teste cardiopulmonar em esteira rolante e testes de 1RM nos exercícios: leg-press 45º, cadeira extensora, mesa flexora, supino reto, puxador costas, desenvolvimento com a barra, rosca direta e tríceps com a barra. Os testes foram realizados antes e após 12 semanas. No período proposto, os grupos realizaram: I - GT: exercícios resistidos, os mesmos dos testes de 1RM, com três séries de 25 repetições, com aproximadamente 30% de 1RM; II - GC: não realizou nenhum treinamento físico. Após 12 semanas, o GC não apresentou alterações nas variáveis estudadas (p > 0,05. O GT apresentou aumento significante da massa magra (p 0,05. Conclui-se que o treinamento de resistência de força com alto número de repetições proporcionou melhora da potência aeróbia das voluntárias, evidenciado pelo aumento do consumo máximo de oxigênio, embora não tenha modificado o limiar ventilatório.The effects of strength training on women's cardiorespiratory capacity have not been widely established. The purpose of this study was to investigate the effects of resistance strength training with high number of repetitions on maximum oxygen uptake and ventilatory threshold in young women during 12 weeks. Twenty women, aged 21.2 + 2.7 years, were included in the study and assigned to two groups: I - resistance strength training with high number of repetitions group (TG

  1. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Thyroid Scan and Uptake ...

  2. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... information. The thyroid scan and thyroid uptake provide information about the structure and function of the thyroid. The thyroid is a gland in the neck that controls metabolism , a chemical process that regulates the rate at which the body ...

  3. Radioactive uptake by plants

    Energy Technology Data Exchange (ETDEWEB)

    Horak, O

    1986-01-01

    The fundamentals of radionuclide uptake by plants, both by leaves and roots are presented. Iodine, cesium, strontium and ruthenium are considered and a table of the measured concentrations in several agricultural plants shortly after the Chernobyl accident is presented. Another table gives the Cs and Sr transfer factors soil plants for some plants. By using them estimates of future burden can be obtained.

  4. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... type your comment or suggestion into the following text box: Comment: E-mail: Area code: Phone no: ... of a typical probe counter used for thyroid uptake exams. The patient sits with the camera directed at the neck for five minutes, and then the leg for ...

  5. Thyroid Scan and Uptake

    Science.gov (United States)

    ... type your comment or suggestion into the following text box: Comment: E-mail: Area code: Phone no: ... of a typical probe counter used for thyroid uptake exams. The patient sits with the camera directed at the neck for five minutes, and then the leg for ...

  6. Oxygen uptake of overweight and obese children at different stages of a progressive treadmill test: Consumo de oxígeno de niños y niñas con sobrepeso y obesos en los diferentes estadios de una prueba progresiva en un tapiz rodante.

    Science.gov (United States)

    Meléndez-Ortega, Agustín; Lucy Davis, Catherine; Barbeau, Paule; Boyle, Colleen Ann

    2010-01-01

    INTRODUCTION: Maximal oxygen uptake (VO2 max) is associated with cardiovascular and metabolic risks but it is difficult to assess in obese children. The objective of this study was to develop an equation to estimate VO2 (mL/kg/min) and to check the % of tests that were maximal according to recommended criteria. METHODS: Stress tests were analyzed of 222 subjects (94 male and 128 female with a BMI above the 85 percentile for age and sex), and repeated 4 months later. Mean age was 9.4 ± 1.1 years and weighed 52.4 ± 13.3 kg. Body fat % (40.5 + 6.2) was determined by DXA (Hologic QDR 4500W). The protocol on the treadmill started with a warm up at 2.5 and 3 mph with a slope of 0% and 2%. The speed was kept at 3 mph for all the stages and the slope was increased 2% every 2 minutes. Statistical analysis (descriptive, t-test and ANOVAS 2×2×2) was done with SPSS 15.0. RESULTS: Only 35% of the tests were maximal. The equation calculates was Y = 2.6x + 22.3 (x = protocol stage). Data pre and post treatment were not statistically different DISCUSSION: Increments in VO2 were consistent despite subject diversity (sex, % body fat, physical fitness, treatment). CONCLUSION: To be able to estimate VO2 at the different stages of the test without complex equipment or specialized staff, will facilitate the performance of stress tests on a daily basis.

  7. OXYGEN TRANSPORT CERAMIC MEMBRANES

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2000-10-01

    This is the third quarterly report on oxygen Transport Ceramic Membranes. In the following, the report describes the progress made by our university partners in Tasks 1 through 6, experimental apparatus that was designed and built for various tasks of this project, thermodynamic calculations, where applicable and work planned for the future. (Task 1) Design, fabricate and evaluate ceramic to metal seals based on graded ceramic powder/metal braze joints. (Task 2) Evaluate the effect of defect configuration on ceramic membrane conductivity and long term chemical and structural stability. (Task 3) Determine materials mechanical properties under conditions of high temperatures and reactive atmospheres. (Task 4) Evaluate phase stability and thermal expansion of candidate perovskite membranes and develop techniques to support these materials on porous metal structures. (Task 5) Assess the microstructure of membrane materials to evaluate the effects of vacancy-impurity association, defect clusters, and vacancy-dopant association on the membrane performance and stability. (Task 6) Measure kinetics of oxygen uptake and transport in ceramic membrane materials under commercially relevant conditions using isotope labeling techniques.

  8. 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, ...

  9. Cardiorespiratory adaptations induced by aerobic training in middle-aged men: the importance of a decrease in sympathetic stimulation for the contribution of dynamic exercise tachycardia

    Directory of Open Access Journals (Sweden)

    Chacon-Mikahil M.P.T.

    1998-01-01

    Full Text Available We investigated the effects of aerobic training on the efferent autonomic control of heart rate (HR during dynamic exercise in middle-aged men, eight of whom underwent exercise training (T while the other seven continued their sedentary (S life style. The training was conducted over 10 months (three 1-h sessions/week on a field track at 70-85% of the peak HR. The contribution of sympathetic and parasympathetic exercise tachycardia was determined in terms of differences in the time constant effects on the HR response obtained using a discontinuous protocol (4-min tests at 25, 50, 100 and 125 watts on a cycle ergometer, and a continuous protocol (25 watts/min until exhaustion allowed the quantification of the parameters (anaerobic threshold, VO2 AT; peak O2 uptake, VO2 peak; power peak that reflect oxygen transport. The results obtained for the S and the T groups were: 1 a smaller resting HR in T (66 beats/min when compared to S (84 beats/min; 2 during exercise, a small increase in the fast tachycardia (D0-10 s related to vagal withdrawal (P<0.05, only at 25 watts was observed in T at all powers; at middle and higher powers a significant decrease (P<0.05 at 50, 100 and 125 watts in the slow tachycardia (D1-4 min related to a sympathetic-dependent mechanism was observed in T; 3 the VO2 AT (S = 1.06 and T = 1.33 l/min and VO2 peak (S = 1.97 and T = 2.47 l/min were higher in T (P<0.05. These results demonstrate that aerobic training can induce significant physiological adaptations in middle-aged men, mainly expressed as a decrease in the sympathetic effects on heart rate associated with an increase in oxygen transport during dynamic exercise.

  10. Oxygen diffusion in zircon

    Science.gov (United States)

    Watson, E. B.; Cherniak, D. J.

    1997-05-01

    Oxygen diffusion in natural, non-metamict zircon was characterized under both dry and water-present conditions at temperatures ranging from 765°C to 1500°C. Dry experiments were performed at atmospheric pressure by encapsulating polished zircon samples with a fine powder of 18O-enriched quartz and annealing the sealed capsules in air. Hydrothermal runs were conducted in cold-seal pressure vessels (7-70 MPa) or a piston cylinder apparatus (400-1000 MPa) on zircon samples encapsulated with both 18O-enriched quartz and 18O water. Diffusive-uptake profiles of 18O were measured in all samples with a particle accelerator, using the 18O(p, α) 15N reaction. For dry experimental conditions at 1100-1500°C, the resulting oxygen diffusivities (24 in all) are well described by: D dry (m 2/s) = 1.33 × 10 -4exp(-53920/T) There is no suggestion of diffusive anisotropy. Under wet conditions at 925°C, oxygen diffusion shows little or no dependence upon P H 2O in the range 7-1000 MPa, and is insensitive to total pressure as well. The results of 27 wet experiments at 767-1160°C and 7-1000 MPa can be described a single Arrhenius relationship: D wet (m 2/s) = 5.5 × 10 -12exp(-25280/T) The insensitivity of oxygen diffusion to P H 2O means that applications to geologic problems can be pursued knowing only whether the system of interest was 'wet' (i.e., P H 2O > 7MPa ) or 'dry'. Under dry conditions (presumably rare in the crust), zircons are extremely retentive of their oxygen isotopic signatures, to the extent that δ 18O would be perturbed at the center of a 200 μm zircon only during an extraordinarily hot and protracted event (e.g., 65 Ma at 900°C). Under wet conditions, δ 18O may or may not be retained in the central regions of individual crystals, cores or overgrowth rims, depending upon the specific thermal history of the system.

  11. Clinical and experimental analysis of 201thallium uptake of the heart

    International Nuclear Information System (INIS)

    Strauer, B.E.; Buell, U.; Buerger, S.; Klinikum Grosshadern, Muenchen

    1978-01-01

    Studies were carried out in order to determine the factors influencing myocardial 201 Tl uptake. A total of 158 patients was examined with regard to both 201 Tl uptake and the assessment of left ventricular and coronary function. Moreover, 42 animal experiments were performed. The results demonstrate that: 1) 201 Tl uptake in the normal and hypertrophied human heart is linearly correlated with the muscle mass of the left ventricle (LVMM); 2) 201 Tl uptake is enhanced in the inner layer and is decreased in the outer layer of the left ventricular wall. The 201 Tl uptake of the right ventricle is 40% lower in comparison to the left ventricle; 3) the basic correlation between 201 Tl uptake and LVMM is influenced by alterations of both myocardial flow and myocardial oxygen consumption; and 4) inotropic interventions (isoproterenol, calcium, norepinephrine) as well as coronary dilatation (dipyridamole) may considerably augment 201 Tl uptake in accordance with changes in myocardial oxygen consumption and/or myocardial flow. It is concluded that myocardial 201 Tl uptake is determined by multiple factors. The major determinants have been shown to include muscle mass, myocardial flow and myocardial oxygen consumption. The clinical data obtained from patient groups with normal ventricular function, with coronary artery disease, with left ventricular wall motion abnormalities and with different degree of left ventricular hypertrophy are correlated with quantitated myocardial 201 Tl uptake. (orig./MG) [de

  12. Cardiorespiratory responses of a dance session designed for older women: A cross sectional study.

    Science.gov (United States)

    Rodrigues-Krause, Josianne; Farinha, Juliano Boufleur; Ramis, Thiago Rozales; Boeno, Francesco Pinto; Dos Santos, Gabriela Cristina; Krause, Mauricio; Reischak-Oliveira, Alvaro

    2018-06-04

    Dancing has been increasingly used as a type of exercise intervention to improve cardiovascular fitness of older people. However, it is unclear which may be the exercise intensity of the dance sessions. To describe cardiorespiratory responses of a dance session for older women, and to identify intensity zones in relation to peak oxygen consumption (VO 2 peak), first and second ventilatory thresholds (VT1 and VT2). Ten women (66 ± 5 yrs., BMI 27 ± 4) were examined on three occasions: Familiarization, maximum effort and dance sessions. Incremental treadmill test: 5 km/h, 2% slope each min, until maximum effort. Dance class (60 min): warm-up (20 min), across-the-floor (10 min), choreography (15 min), show (10 min) and cool-down (5 min). Ventilatory parameters were measured continuously (breath-by-breath). VO 2 (mL·kg -1 ·min -1 ): Maximum effort: VO 2 peak (23.3 ± 4.3), VT1 (17.2 ± 3.5) and VT2 (20.9 ± 3.4). Dancing: warm-up (12.8 ± 2.4, ~55%VO 2 peak), across-the-floor (14.2 ± 2.4 ~62%VO 2 peak), choreography (14.6 ± 3.2 ~63%VO 2 peak) and show (16.1 ± 3.3, ~69% VO 2 peak). Show was similar to VT1. Cardiorespiratory demands of a dance class for older women are at low aerobic intensity. Show was similar to VT1, indicating that a dance class may be modulated to improve aerobic fitness, at least at initial stages of training. Copyright © 2018 Elsevier Inc. All rights reserved.

  13. Mechanisms of Attenuation of Pulmonary V'O2 Slow Component in Humans after Prolonged Endurance Training.

    Directory of Open Access Journals (Sweden)

    Jerzy A Zoladz

    Full Text Available In this study we have examined the effect of prolonged endurance training program on the pulmonary oxygen uptake (V'O2 kinetics during heavy-intensity cycling-exercise and its impact on maximal cycling and running performance. Twelve healthy, physically active men (mean±SD: age 22.33±1.44 years, V'O2peak 3198±458 mL ∙ min-1 performed an endurance training composed mainly of moderate-intensity cycling, lasting 20 weeks. Training resulted in a decrease (by ~5%, P = 0.027 in V'O2 during prior low-intensity exercise (20 W and in shortening of τp of the V'O2 on-kinetics (30.1±5.9 s vs. 25.4±1.5 s, P = 0.007 during subsequent heavy-intensity cycling. This was accompanied by a decrease of the slow component of V'O2 on-kinetics by 49% (P = 0.001 and a decrease in the end-exercise V'O2 by ~5% (P = 0.005. An increase (P = 0.02 in the vascular endothelial growth factor receptor 2 mRNA level and a tendency (P = 0.06 to higher capillary-to-fiber ratio in the vastus lateralis muscle were found after training (n = 11. No significant effect of training on the V'O2peak was found (P = 0.12. However, the power output reached at the lactate threshold increased by 19% (P = 0.01. The power output obtained at the V'O2peak increased by 14% (P = 0.003 and the time of 1,500-m performance decreased by 5% (P = 0.001. Computer modeling of the skeletal muscle bioenergetic system suggests that the training-induced decrease in the slow component of V'O2 on-kinetics found in the present study is mainly caused by two factors: an intensification of the each-step activation (ESA of oxidative phosphorylation (OXPHOS complexes after training and decrease in the ''additional" ATP usage rising gradually during heavy-intensity exercise.

  14. Improvements in Key Cardiopulmonary Exercise Testing Variables Following Cardiac Rehabilitation in Patients With Coronary Artery Disease.

    Science.gov (United States)

    Popovic, Dejana; Kumar, Nikhil; Chaudhry, Sundeep; Bagai, Akshay; Arena, Ross; Kumar, Naresh

    2018-05-11

    Improvements in cardiorespiratory fitness (VO2peak) post-cardiac rehabilitation (post-CR) are used to gauge therapeutic efficacy. The aim of the present study was to assess the effect of supervised CR on other cardiopulmonary exercise testing (CPX) variables, specifically those that reflect ventilatory efficiency and VO2 changes in relation to changes in work rate (WR). Patients (n = 142; mean age 63 ± 9 y; 23% female) with coronary artery disease (CAD) participated in supervised CR for 3 to 6 mo completing 60 ± 17 sessions (range: 32-96 sessions), with intensity derived from the baseline CPX. CPX was completed at baseline and post-CR on a cycle ergometer. The minimum heart rate (HR) during cycling was set 5 to 10 beats/min above the HR at ventilatory anaerobic threshold (VAT) while the maximum HR remained below the ischemic threshold observed during CPX, and this intensity was maintained for 25 min. VO2peak, peak O2 pulse, the minute ventilation/carbon dioxide production (VE/VCO2) slope, the oxygen uptake efficiency slope (OUES), and the ΔVO2/ΔWR slope were determined at baseline and post-CR. Following CR, there were significant improvements (all P < .001) in VO2peak (17.7 ± 4.7 mL/kg/min vs 20.9 ± 5.4 mL/kg/min), peak O2 pulse (11.6 ± 3.2 mL/beat vs 13.4 ± 3.6 mL/beat), VE/VCO2 slope (28.4 ± 5.3 vs 27.5 ± 4.7), OUES (1.8 ± 0.5 vs 2.0 ± 0.6), and ΔVO2/ΔWR slope (9.1 ± 1.2 mL/min/W vs 9.6 ± 1.1 mL/min/W). Key markers of ventilatory efficiency and VO2 kinetics during CPX significantly improve following CR. Expanding the list of variables assessed via CPX may provide better resolution in validation of CR therapeutic efficacy in patients with CAD.

  15. Effects of high intensity training and continuous endurance training on aerobic capacity and body composition in recreationally active runners.

    Science.gov (United States)

    Hottenrott, Kuno; Ludyga, Sebastian; Schulze, Stephan

    2012-01-01

    The aim of the study was to examine the effects of two different training programs (high-intensity-training vs. continuous endurance training) on aerobic power and body composition in recreationally active men and women and to test whether or not participants were able to complete a half marathon after the intervention period. Thirty-four recreational endurance runners were randomly assigned either to a Weekend-Group (WE, n = 17) or an After-Work- Group (AW, n = 17) for a 12 week-intervention period. WE weekly completed 2 h 30 min of continuous endurance running composed of 2 sessions on the weekend. In contrast, AW performed 4 30 min sessions of high intensity training and an additional 30 min endurance run weekly, always after work. During an exhaustive treadmill test aerobic power was measured and heart rate was continuously recorded. Body composition was assessed using bio-impedance. Following the intervention period all subjects took part in a half-marathon. AW significantly improved peak oxygen uptake (VO2 peak) from 36.8 ± 4.5 to 43.6 ± 6.5 [mL.min(-1).kg(-1)], velocity at lactate threshold (VLT) from 9.7 ± 2.2 to 11.7 ± 1.8 [km.h(-1)] and visceral fat from 5.6 ± 2.2 to 4.7 ± 1.9 In WE VO2 peak signifi-cantly increased from 38.8 ± 5.0 to 41.5 ± 6.0 [mL.min(-1).kg(-1)], VLT from 9.9 ± 1.3 to 11.2 ± 1.7 [km.h(-1)] and visceral fat was reduced from 5.7 ± 2.1 to 5.4 ± 1.9 (p marathon with no significant differences in performance (p = 0.63). Short, intensive endurance training sessions of about 30 min are effective in improving aerobic fitness in recreationally active runners. Key pointsContinuous endurance training and high intensity training lead to significant improvements of aerobic capacity and body compositionBoth training methods enable recreationally active runners to finish a half-marathonHigh intensity training is favorable to improve VO2 peak.

  16. EFFECTS OF HIGH INTENSITY TRAINING AND CONTINUOUS ENDURANCE TRAINING ON AEROBIC CAPACITY AND BODY COMPOSITION IN RECREATIONALLY ACTIVE RUNNERS

    Directory of Open Access Journals (Sweden)

    Kuno Hottenrott

    2012-09-01

    Full Text Available The aim of the study was to examine the effects of two different training programs (high-intensity-training vs. continuous endurance training on aerobic power and body composition in recreationally active men and women and to test whether or not participants were able to complete a half marathon after the intervention period. Thirty-four recreational endurance runners were randomly assigned either to a Weekend-Group (WE, n = 17 or an After-Work- Group (AW, n = 17 for a 12 week-intervention period. WE weekly completed 2 h 30 min of continuous endurance running composed of 2 sessions on the weekend. In contrast, AW performed 4 30 min sessions of high intensity training and an additional 30 min endurance run weekly, always after work. During an exhaustive treadmill test aerobic power was measured and heart rate was continuously recorded. Body composition was assessed using bio-impedance. Following the intervention period all subjects took part in a half-marathon. AW significantly improved peak oxygen uptake (VO2 peak from 36.8 ± 4.5 to 43.6 ± 6.5 [mL.min-1.kg-1], velocity at lactate threshold (VLT from 9.7 ± 2.2 to 11.7 ± 1.8 [km.h-1] and visceral fat from 5.6 ± 2.2 to 4.7 ± 1.9 In WE VO2 peak signifi-cantly increased from 38.8 ± 5.0 to 41.5 ± 6.0 [mL.min-1.kg-1], VLT from 9.9 ± 1.3 to 11.2 ± 1.7 [km.h-1] and visceral fat was reduced from 5.7 ± 2.1 to 5.4 ± 1.9 (p < 0.01. Only the improvements of VO2 peak were significantly greater in AW compared with WE (pre/post group interaction: F=15.4, p = 0.01, η2 = 0.36. Both groups completed a half marathon with no significant differences in performance (p = 0.63. Short, intensive endurance training sessions of about 30 min are effective in improving aerobic fitness in recreationally active runners

  17. Neuroticism personality trait is associated with Quality of Life in patients with Chronic Heart Failure

    Institute of Scientific and Technical Information of China (English)

    Lampros; Samartzis; Stavros; Dimopoulos; Christos; Manetos; Varvara; Agapitou; Athanasios; Tasoulis; Eleni; Tseliou; Iraklis; Pozios; Elisavet; Kaldara; John; Terrovitis; Serafim; Nanas

    2014-01-01

    AIM: To evaluate Quality of life(QoL) in chronic heart failure(CHF) in relation to Neuroticism personality trait and CHF severity.METHODS: Thirty six consecutive, outpatients with Chronic Heart Failure(6 females and 30 males, mean age: 54 ± 12 years), with a left ventricular ejection fraction ≤ 45% at optimal medical treatment at the time of inclusion, were asked to answer the Kansas City Cardiomyopathy Questionnaire(KCCQ) for Quality ofLife assessment and the NEO Five-Factor Personality Inventory for personality assessment. All patients un-derwent a symptom limited cardiopulmonary exercise testing on a cycle-ergometer, in order to access CHF severity. A multivariate linear regression analysis us-ing simultaneous entry of predictors was performed to examine which of the CHF variables and of the person-ality variables were correlated independently to QoL scores in the two summary scales of the KCCQ, namely the Overall Summary Scale and the Clinical Summary Scale.RESULTS: The Neuroticism personality trait score had a significant inverse correlation with the Clinical Sum-mary Score and Overall Summary Score of the KCCQ(r =-0.621, P < 0.05 and r =-0.543, P < 0.001, respec-tively). KCCQ summary scales did not show significant correlations with the personality traits of Extraversion, Openness, Conscientiousness and Agreeableness. Mul-tivariate linear regression analysis using simultaneous entry of predictors was also conducted to determine the best linear combination of statistically significant univari-ate predictors such as Neuroticism, VE/VCO2 slope and VO2 peak, for predicting KCCQ Clinical Summary Score. The results show Neuroticism(β =-0.37, P < 0.05), VE/VCO2 slope(β =-0.31, P < 0.05) and VO2 peak(β = 0.37, P < 0.05) to be independent predictors of QoL. In multivariate regression analysis Neuroticism(b =-0.37, P < 0.05), the slope of ventilatory equivalent for carbon dioxide output during exercise,(VE/VCO2 slope)(b =-0.31, P < 0.05) and peak oxygen uptake(VO

  18. Mechanisms of Attenuation of Pulmonary V'O2 Slow Component in Humans after Prolonged Endurance Training.

    Science.gov (United States)

    Zoladz, Jerzy A; Majerczak, Joanna; Grassi, Bruno; Szkutnik, Zbigniew; Korostyński, Michał; Gołda, Sławomir; Grandys, Marcin; Jarmuszkiewicz, Wiesława; Kilarski, Wincenty; Karasinski, Janusz; Korzeniewski, Bernard

    2016-01-01

    In this study we have examined the effect of prolonged endurance training program on the pulmonary oxygen uptake (V'O2) kinetics during heavy-intensity cycling-exercise and its impact on maximal cycling and running performance. Twelve healthy, physically active men (mean±SD: age 22.33±1.44 years, V'O2peak 3198±458 mL ∙ min-1) performed an endurance training composed mainly of moderate-intensity cycling, lasting 20 weeks. Training resulted in a decrease (by ~5%, P = 0.027) in V'O2 during prior low-intensity exercise (20 W) and in shortening of τp of the V'O2 on-kinetics (30.1±5.9 s vs. 25.4±1.5 s, P = 0.007) during subsequent heavy-intensity cycling. This was accompanied by a decrease of the slow component of V'O2 on-kinetics by 49% (P = 0.001) and a decrease in the end-exercise V'O2 by ~5% (P = 0.005). An increase (P = 0.02) in the vascular endothelial growth factor receptor 2 mRNA level and a tendency (P = 0.06) to higher capillary-to-fiber ratio in the vastus lateralis muscle were found after training (n = 11). No significant effect of training on the V'O2peak was found (P = 0.12). However, the power output reached at the lactate threshold increased by 19% (P = 0.01). The power output obtained at the V'O2peak increased by 14% (P = 0.003) and the time of 1,500-m performance decreased by 5% (P = 0.001). Computer modeling of the skeletal muscle bioenergetic system suggests that the training-induced decrease in the slow component of V'O2 on-kinetics found in the present study is mainly caused by two factors: an intensification of the each-step activation (ESA) of oxidative phosphorylation (OXPHOS) complexes after training and decrease in the ''additional" ATP usage rising gradually during heavy-intensity exercise.

  19. Reliability and Validity of the Dutch Physical Activity Questionnaires for Children (PAQ-C) and Adolescents (PAQ-A).

    Science.gov (United States)

    Bervoets, Liene; Van Noten, Caroline; Van Roosbroeck, Sofie; Hansen, Dominique; Van Hoorenbeeck, Kim; Verheyen, Els; Van Hal, Guido; Vankerckhoven, Vanessa

    2014-01-01

    This study was designed to validate the Dutch Physical Activity Questionnaires for Children (PAQ-C) and Adolescents (PAQ-A). After adjustment of the original Canadian PAQ-C and PAQ-A (i.e. translation/back-translation and evaluation by expert committee), content validity of both PAQs was assessed and calculated using item-level (I-CVI) and scale-level (S-CVI) content validity indexes. Inter-item and inter-rater reliability of 196 PAQ-C and 95 PAQ-A filled in by both children or adolescents and their parent, were evaluated. Inter-item reliability was calculated by Cronbach's alpha (α) and inter-rater reliability was examined by percent observed agreement and weighted kappa (κ). Concurrent validity of PAQ-A was examined in a subsample of 28 obese and 16 normal-weight children by comparing it with concurrently measured physical activity using a maximal cardiopulmonary exercise test for the assessment of peak oxygen uptake (VO2 peak). For both PAQs, I-CVI ranged 0.67-1.00. S-CVI was 0.89 for PAQ-C and 0.90 for PAQ-A. A total of 192 PAQ-C and 94 PAQ-A were fully completed by both child and parent. Cronbach's α was 0.777 for PAQ-C and 0.758 for PAQ-A. Percent agreement ranged 59.9-74.0% for PAQ-C and 51.1-77.7% for PAQ-A, and weighted κ ranged 0.48-0.69 for PAQ-C and 0.51-0.68 for PAQ-A. The correlation between total PAQ-A score and VO2 peak - corrected for age, gender, height and weight - was 0.516 (p = 0.001). Both PAQs have an excellent content validity, an acceptable inter-item reliability and a moderate to good strength of inter-rater agreement. In addition, total PAQ-A score showed a moderate positive correlation with VO2 peak. Both PAQs have an acceptable to good reliability and validity, however, further validity testing is recommended to provide a more complete assessment of both PAQs.

  20. 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.

  1. Validation and Refinement of Prediction Models to Estimate Exercise Capacity in Cancer Survivors Using the Steep Ramp Test

    NARCIS (Netherlands)

    Stuiver, Martijn M.; Kampshoff, Caroline S.; Persoon, Saskia; Groen, Wim; van Mechelen, Willem; Chinapaw, Mai J. M.; Brug, Johannes; Nollet, Frans; Kersten, Marie-José; Schep, Goof; Buffart, Laurien M.

    2017-01-01

    Objective: To further test the validity and clinical usefulness of the steep ramp test (SRT) in estimating exercise tolerance in cancer survivors by external validation and extension of previously published prediction models for peak oxygen consumption (Vo2(peak)) and peak power output (W-peak).&

  2. Exosomes: Mechanisms of Uptake

    Directory of Open Access Journals (Sweden)

    Kelly J. McKelvey

    2015-07-01

    Full Text Available Exosomes are 30–100 nm microvesicles which contain complex cellular signals of RNA, protein and lipids. Because of this, exosomes are implicated as having limitless therapeutic potential for the treatment of cancer, pregnancy complications, infections, and autoimmune diseases. To date we know a considerable amount about exosome biogenesis and secretion, but there is a paucity of data regarding the uptake of exosomes by immune and non-immune cell types (e.g., cancer cells and the internal signalling pathways by which these exosomes elicit a cellular response. Answering these questions is of paramount importance.

  3. Exosomes: Mechanisms of Uptake

    Directory of Open Access Journals (Sweden)

    Kelly J. McKelvey

    2015-07-01

    Full Text Available Exosomes are 30–100 nm microvesicles which contain complex cellular signals of RNA, protein and lipids. Because of this, exosomes are implicated as having limitless therapeutic potential for the treatment of cancer, pregnancy complications, infections, and autoimmune diseases. To date we know a considerable amount about exosome biogenesis and secretion, but there is a paucity of data regarding the uptake of exosomes by immune and non- immune cell types (e.g., cancer cells and the internal signalling pathways by which these exosomes elicit a cellular response. Answering these questions is of para‐ mount importance.

  4. Thyroid hormone stimulated glucose uptake in human mononuclear blood cells from normal persons and from patients with non-insulin-dependent diabetes mellitus

    DEFF Research Database (Denmark)

    Kvetny, J; Matzen, L

    1989-01-01

    Thyroxine and T3 induced oxygen consumption and glucose uptake were studied in vitro in mononuclear blood cells isolated from patients with non-insulin-dependent diabetes mellitus (NIDDM) and from non-diabetic control persons. Cellular oxygen consumption and glucose uptake were promptly increased...

  5. 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....

  6. Thyroid Uptake Measurement System

    International Nuclear Information System (INIS)

    Nguyen Duc Tuan; Nguyen Thi Bao My; Nguyen Van Sy

    2007-01-01

    The NED-UP.M7 is a complete thyroid uptake and analysis system specifically designed for nuclear medicine. Capable of performing a full range of studies this system provides fast, accurate results for Uptake Studies. The heart of the NED-UP.M7 is a microprocessor-controlled 2048 channel Compact Multi-Channel Analyzer, coupled to a 2 inch x 2 inch NaI(Tl) detector with a USB personal computer interface. The system offers simple, straight-forward operation using pre-programmed isotopes, and menudriven prompts to guide the user step by step through each procedure. The pre-programmed radionuclides include I-123, I-125, I-131, Tc-99m and Cs-137. The user-defined radionuclides also allow for isotope identification while the printer provides hard copy printouts for patient and department record keeping. The included software program running on PC (Windows XP-based) is a user friendly program with menudriven and graphic interface for easy controlling the system and managing measurement results of patient on Excel standard form. (author)

  7. Effects of eHealth physical activity encouragement in adolescents with complex congenital heart disease: The PReVaiL randomized clinical trial.

    Science.gov (United States)

    Klausen, Susanne Hwiid; Andersen, Lars L; Søndergaard, Lars; Jakobsen, Janus Christian; Zoffmann, Vibeke; Dideriksen, Kasper; Kruse, Anne; Mikkelsen, Ulla Ramer; Wetterslev, Jørn

    2016-10-15

    To assess benefit and harms of adding an eHealth intervention to health education and individual counseling in adolescents with congenital heart disease. Randomized clinical trial. Denmark. A total of 158 adolescents aged 13-16years with no physical activity restrictions after repaired complex congenital heart disease. PReVaiL consisted of individually tailored eHealth encouragement physical activity for 52weeks. All patients received 45min of group-based health education and 15min of individual counseling involving patients' parents. The primary outcome was maximal oxygen uptake (VO2 peak) at 52weeks after randomization. The secondary outcome was physical activity. Exploratory outcomes were generic and disease-specific questionnaires. In the intervention group, 58 patients (72%) completed the final test, but of those, only 46 (57%) fulfilled the compliance criteria of using the eHealth application for at least 2 consecutive weeks. In the control group, 61 patients (79%) completed both exercise tests. Adjusted for baseline values, the difference between the intervention group and the control group in mean VO2 peak at 1year was -0.65ml·kg(-1)·min(-1) (95% CI -2.66 to 1.36). Between-group differences at 1year in physical activity, generic health-related quality of life, and disease-specific quality of life were not statistically significant. Adding a tailored eHealth intervention to health education and individual counseling did not affect outcomes among adolescents with congenital heart disease. Our results do not support the use of this eHealth intervention in adolescents with complex congenital heart disease. Clinical trials.gov identifier: NCT01189981. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  8. Exercise Metabolism in Nonobese Patients with Type 2 Diabetes Following the Acute Restoration of Normoglycaemia

    Directory of Open Access Journals (Sweden)

    Christopher J. Gaffney

    2017-01-01

    Full Text Available This study investigated how acute restoration of normoglycaemia affected energy metabolism during exercise in nonobese patients with type 2 diabetes. Six subjects (mean ± SEM aged 56.2 ± 2.7 years, with a BMI of 24.5 ± 1.5 kg/m2 and a VO2 peak of 28.7 ml/kg/min, attended the lab on two randomised occasions for a four-hour resting infusion of insulin or saline, followed by 30 minutes cycling at 50% VO2 peak. During the 4 h resting infusion, there was a greater (P<0.0001 reduction in blood glucose in insulin treatment (INS (from 11.2 ± 0.6 to 5.6 ± 0.1 mmol/l than in saline treatment/control (CON (from 11.5 ± 0.7 to 8.5 ± 0.6 mmol/l. This was associated with a lower (P<0.05 resting metabolic rate in INS (3.87 ± 0.17 than in CON (4.39 ± 0.30 kJ/min. During subsequent exercise, blood glucose increased significantly in INS from 5.6 ± 0.1 at 0 min to 6.3 ± 0.3 mmol/l at 30 min (P<0.01, which was accompanied by a lower blood lactate response (P<0.05. Oxygen uptake, rates of substrate utilization, heart rate, and ratings of perceived exertion were not different between trials. Insulin-induced normoglycaemia increased blood glucose during subsequent exercise without altering overall substrate utilization.

  9. Total body fat, abdominal fat, body fat distribution and surrogate markers for health related to adipocyte fatty acid-binding protein (FABP4) in children.

    Science.gov (United States)

    Dencker, Magnus; Danielson, Anton; Karlsson, Magnus K; Wollmer, Per; Andersen, Lars B; Thorsson, Ola

    2017-04-01

    The aim of the study was to assess possible relationships between adipocyte fatty acid-binding protein (FABP4) and total body fat (TBF), abdominal fat, body fat distribution, aerobic fitness, blood pressure, cardiac dimensions and the increase in body fat over 2 years in a community sample of children. A cross-sectional study was used in a community sample of 170 (92 boys and 78 girls) children aged 8-11 years. TBF and abdominal fat (AFM) were measured by dual-energy X-ray absorptiometry (DXA). TBF was also expressed as percentage of total body mass (BF%), and body fat distribution was calculated as AFM/TBF. Maximal oxygen uptake (VO2PEAK) was assessed by indirect calorimetry during a maximal exercise test and scaled to body mass. Systolic and diastolic blood pressure (SBP and DBP) and pulse pressure (PP) were measured. Echocardiography was performed. Left atrial (LA) size was measured, and left ventricular mass (LVM) was calculated. A follow-up DXA scan was available in 152 children (84 boys and 68 girls). Frozen serum samples were analyzed for FABP4. Partial correlations, with adjustment for sex, between FABP4 vs. ln TBF, ln BF%, ln AFM, AFM/TBF and VO2PEAK were (r=0.69, 0.68, 0.69, 0.49 and -0.39, pfat or change in fat distribution were not correlated.) Conclusions: Findings from this community-based cohort of young children show that increased body fat and abdominal fat, more abdominal body fat distribution, low fitness, more LVM and increased LA, increased SBP and PP were all associated with increased levels of FABP4. Increase in TBF and abdominal fat over 2 years were also associated with increased levels of FABP4.

  10. Effects of four-month handbike training under free-living conditions on physical fitness and health in wheelchair users.

    Science.gov (United States)

    Hoekstra, Sven; Valent, Linda; Gobets, David; van der Woude, Lucas; de Groot, Sonja

    2017-08-01

    Recognizing the encouraging effect of challenging events, the HandbikeBattle (HBB) was created to promote exercise among wheelchair users. The purpose of this study was to reveal the effects on physical fitness and health outcomes of four-month handbike training under free-living conditions in preparation for the event. In this prospective cohort study, 59 relatively inexperienced handyclists participated in the HBB of 2013 or 2014. Incremental exercise tests were conducted, respiratory function was tested and anthropometrics were measured before and after the preparation period. Main outcome measures were peak power output (POpeak), peak oxygen uptake (VO2peak) and waist circumference, of which the changes were tested using repeated measures ANOVA. To detect possible determinants of changes in physical fitness, a linear regression analysis was conducted with personal characteristics, executed training volume and upper-extremity complaints during the training period as independent variables. POpeak, VO2peak and waist circumference improved significantly with 17%, 7% and 4.1%, respectively. None of the included variables were significant determinants for the changes in POpeak found as a result of the training. A challenging event such as the HBB provokes training regimes among participants of sufficient load to realize substantial improvements in physical fitness and health outcomes. Implications for Rehabilitation Due to the often impaired muscle function in the lower-limbs and an inactive lifestyle, wheelchair users generally show considerably lower levels of fitness compared to able-bodied individuals. This prospective cohort study showed that four months of handbike training under free-living conditions in preparation for this event resulted in substantial improvements in physical fitness and health outcomes in wheelchair users. The creation of a challenging event such as the HandbikeBattle as part of a follow-up rehabilitation practice can therefore be a useful

  11. Physiological correlates of skating performance in women's and men's ice hockey.

    Science.gov (United States)

    Gilenstam, Kajsa M; Thorsen, Kim; Henriksson-Larsén, Karin B

    2011-08-01

    The purpose of the current investigation was to identify relationships between physiological off-ice tests and on-ice performance in female and male ice hockey players on a comparable competitive level. Eleven women, 24 ± 3.0 years, and 10 male ice hockey players, 23 ± 2.4 years, were tested for background variables: height, body weight (BW), ice hockey history, and lean body mass (LBM) and peak torque (PT) of the thigh muscles, VO2peak and aerobic performance (Onset of Blood Lactate Accumulation [OBLA], respiratory exchange ratio [RER1]) during an incremental bicycle ergometer test. Four different on-ice tests were used to measure ice skating performance. For women, skating time was positively correlated (p skating time was positively correlated to VO2peak (L O2·min(-1)) in the Acceleration test. The male group had significantly higher physiological test values in all variables (absolute and relative to BW) but not in relation to LBM. Selected off-ice tests predict skating performance for women but not for men. The group of women was significantly smaller and had a lower physiological performance than the group of men and were slower in the on-ice performance tests. However, gender differences in off-ice variables were reduced or disappeared when values were related to LBM, indicating a similar capacity of producing strength and aerobic power in female and male hockey players. Skating performance in female hockey players may be improved by increasing thigh muscle strength, oxygen uptake, and relative muscle mass.

  12. Cardio-respiratory and plasma lactate responses to exercise with low draught resistances in standardbred trotters.

    Science.gov (United States)

    Gottlieb-Vedi, M; Essén-Gustavsson, B; Lindholm, A

    1996-12-01

    Five Standardbred trotters performed treadmill exercise with incrementally increasing trotting velocities for 2 min intervals in three different tests until fatigue. Each test was performed with draught loads of either 10, 20 or 30 kilopond (kp). Each trotting interval was followed by 2 min periods at a walk without draught load. Recordings were made of heart rate (HR), respiratory rate (RR), plasma lactate (PLA) and stride frequency (SF) at the end of each trotting interval. The HR increased to average values of 191 +/- 10,203 +/- 10 and 214 +/- 7 bpm and PLA increased to 3.8 +/- 0.7, 7.3 +/- 3.8 and 10.8 +/- 6.4 mmol/l at 9 m/s in the three tests, respectively. The HR response to exercise was significantly higher with increasing draught loads, and PLA was significantly higher with 30 kp compared to 10 kp draught resistance. The lowest respiratory rate was seen in the test with 30 kp loading. Peak oxygen uptake (VO2peak) was measured in a separate test on a sloped treadmill with increasing velocities without draught load and averaged 70.4 +/- 9.11/min. Muscle biopsies were taken from the gluteus muscle. Individual variations were seen in VO2peak, muscle fibre composition and HR and PLA responses to exercise. In conclusion, at a certain velocity a small increase in draught resistance from 10 to 30 kp significantly increases both the HR and PLA responses. At comparable work intensities the horses differed in circulatory and metabolic responses to exercise.

  13. Skeletal muscle neuronal nitric oxide synthase micro protein is reduced in people with impaired glucose homeostasis and is not normalized by exercise training.

    Science.gov (United States)

    Bradley, Scott J; Kingwell, Bronwyn A; Canny, Benedict J; McConell, Glenn K

    2007-10-01

    Skeletal muscle inducible nitric oxide synthase (NOS) protein is greatly elevated in people with type 2 diabetes mellitus, whereas endothelial NOS is at normal levels. Diabetic rat studies suggest that skeletal muscle neuronal NOS (nNOS) micro protein expression may be reduced in human insulin resistance. The aim of this study was to determine whether skeletal muscle nNOSmicro protein expression is reduced in people with impaired glucose homeostasis and whether exercise training increases nNOSmicro protein expression in these individuals because exercise training increases skeletal muscle nNOSmicro protein in rats. Seven people with type 2 diabetes mellitus or prediabetes (impaired fasting glucose and/or impaired glucose tolerance) and 7 matched (sex, age, fitness, body mass index, blood pressure, lipid profile) healthy controls aged 36 to 60 years participated in this study. Vastus lateralis muscle biopsies for nNOSmicro protein determination were obtained, aerobic fitness was measured (peak pulmonary oxygen uptake [Vo(2) peak]), and glucose tolerance and insulin homeostasis were assessed before and after 1 and 4 weeks of cycling exercise training (60% Vo(2) peak, 50 minutes x 5 d wk(-1)). Skeletal muscle nNOSmicro protein was significantly lower (by 32%) in subjects with type 2 diabetes mellitus or prediabetes compared with that in controls before training (17.7 +/- 1.2 vs 26.2 +/- 3.4 arbitrary units, P glucose homeostasis have reduced skeletal muscle nNOSmicro protein content. However, because exercise training improves insulin sensitivity without influencing skeletal muscle nNOSmicro protein expression, it seems that changes in skeletal muscle nNOSmicro protein are not central to the control of insulin sensitivity in humans and therefore may be a consequence rather than a cause of diabetes.

  14. OXYGEN TRANSPORT CERAMIC MEMBRANES

    International Nuclear Information System (INIS)

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2001-01-01

    Conversion of natural gas to liquid fuels and chemicals is a major goal for the Nation as it enters the 21st Century. Technically robust and economically viable processes are needed to capture the value of the vast reserves of natural gas on Alaska's North Slope, and wean the Nation from dependence on foreign petroleum sources. Technologies that are emerging to fulfill this need are all based syngas as an intermediate. Syngas (a mixture of hydrogen and carbon monoxide) is a fundamental building block from which chemicals and fuels can be derived. Lower cost syngas translates directly into more cost-competitive fuels and chemicals. The currently practiced commercial technology for making syngas is either steam methane reforming (SMR) or a two-step process involving cryogenic oxygen separation followed by natural gas partial oxidation (POX). These high-energy, capital-intensive processes do not always produce syngas at a cost that makes its derivatives competitive with current petroleum-based fuels and chemicals. This project has the following 6 main tasks: Task 1--Design, fabricate and evaluate ceramic to metal seals based on graded ceramic powder/metal braze joints. Task 2--Evaluate the effect of defect configuration on ceramic membrane conductivity and long term chemical and structural stability. Task 3--Determine materials mechanical properties under conditions of high temperatures and reactive atmospheres. Task 4--Evaluate phase stability and thermal expansion of candidate perovskite membranes and develop techniques to support these materials on porous metal structures. Task 5--Assess the microstructure of membrane materials to evaluate the effects of vacancy-impurity association, defect clusters, and vacancy-dopant association on the membrane performance and stability. Task 6--Measure kinetics of oxygen uptake and transport in ceramic membrane materials under commercially relevant conditions using isotope labeling techniques

  15. Oxygen dynamics around buried lesser sandeels Ammodytes tobianus (Linnaeus 1785): mode of ventilation and oxygen requirements

    DEFF Research Database (Denmark)

    Behrens, Jane W; Stahl, Henrik J; Steffensen, John F

    2007-01-01

    The oxygen environment around buried sandeels (Ammodytes tobianus) was monitored by planar optodes. The oxygen penetration depth at the sediment interface was only a few mm. Thus fish, typically buried at 1-4 cm depth, were generally in anoxic sediment. However, they induced an advective transport...... down along the body, referred to as ;plume ventilation'. Yet, within approximately 30 min the oxic plume was replenished by oxygen-depleted water from the gills. The potential for cutaneous respiration by the buried fish was thus of no quantitative importance. Calculations derived by three independent...... methods (each with N=3) revealed that the oxygen uptake of sandeel buried for 6-7 h was 40-50% of previous estimates on resting respirometry of non-buried fish, indicating lower O(2) requirements during burial on a diurnal timescale. Buried fish exposed to decreasing oxygen tensions gradually approached...

  16. The indium-oxygen system, ch. 5

    International Nuclear Information System (INIS)

    Dillen, A.J. van

    1977-01-01

    This chapter is divided into three sections: 1) a survey of the literature concerning the indiumoxygen system, 2) the adsorption of oxygen at pure and partially oxidized indium surfaces in the temperature range 20-180degC, and 3) the oxidation of indium at temperatures above 180degC. The oxygen uptake is determined volumetrically and gravimetrically. The influence of the melting point is considered and the results are compared with data from the literature. The oxide layer is amorphous at lower temperatures but above 350degC, crystallisation of In 2 O 3 takes place

  17. Radioiodine uptake measurements in thyroid

    International Nuclear Information System (INIS)

    Kadireshn, A.; Kapur, S.C.; Samuel, J.R.; Mahajan, M.K.

    1988-01-01

    Evaluation of thyroid function can be carried out by measuring the uptake of orally administered radioactive iodine. The results of the thyroid uptake measurements for the period 1982-1987 in Christian Medical College, Ludhiana are presented here. About 3000 patients were screened during the analysis period. (author)

  18. Aquaporins and root water uptake

    Science.gov (United States)

    Water is one of the most critical resources limiting plant growth and crop productivity, and root water uptake is an important aspect of plant physiology governing plant water use and stress tolerance. Pathways of root water uptake are complex and are affected by root structure and physiological res...

  19. Uptake of nuclides by plants

    International Nuclear Information System (INIS)

    Greger, Maria

    2004-04-01

    This review on plant uptake of elements has been prepared to demonstrate how plants take up different elements. The work discusses the nutrient elements, as well as the general uptake and translocation in plants, both via roots and by foliar absorption. Knowledge of the uptake by the various elements within the periodic system is then reviewed. The work also discusses transfer factors (TF) as well as difficulties using TF to understand the uptake by plants. The review also focuses on species differences. Knowledge necessary to understand and calculate plant influence on radionuclide recirculation in the environment is discussed, in which the plant uptake of a specific nuclide and the fate of that nuclide in the plant must be understood. Plants themselves determine the uptake, the soil/sediment determines the availability of the nuclides and the nuclides themselves can interact with each other, which also influences the uptake. Consequently, it is not possible to predict the nuclide uptake in plants by only analysing the nuclide concentration of the soil/substrate

  20. Uptake of nuclides by plants

    Energy Technology Data Exchange (ETDEWEB)

    Greger, Maria [Stockholm Univ. (Sweden). Dept. of Botany

    2004-04-01

    This review on plant uptake of elements has been prepared to demonstrate how plants take up different elements. The work discusses the nutrient elements, as well as the general uptake and translocation in plants, both via roots and by foliar absorption. Knowledge of the uptake by the various elements within the periodic system is then reviewed. The work also discusses transfer factors (TF) as well as difficulties using TF to understand the uptake by plants. The review also focuses on species differences. Knowledge necessary to understand and calculate plant influence on radionuclide recirculation in the environment is discussed, in which the plant uptake of a specific nuclide and the fate of that nuclide in the plant must be understood. Plants themselves determine the uptake, the soil/sediment determines the availability of the nuclides and the nuclides themselves can interact with each other, which also influences the uptake. Consequently, it is not possible to predict the nuclide uptake in plants by only analysing the nuclide concentration of the soil/substrate.

  1. Oxygen uptake of overweight and obese children at different stages of a progressive treadmill test. (Consumo de oxígeno de niños y niñas con sobrepeso y obesos en los diferentes estadios de una prueba progresiva en un tapiz rodante.

    Directory of Open Access Journals (Sweden)

    Colleen Ann Boyle

    2010-01-01

    Full Text Available AbstractIntroduction: Maximal oxygen uptake (VO2 max is associated with cardiovascular and metabolic risks but it is difficult to assess in obese children. The objective of this study was to develop an equation to estimate VO2 (mL/kg/min and to check the % of tests that were maximal according to recommended criteria. Methods: Stress tests were analyzed of 222 subjects (94 male and 128 female with a BMI above the 85 percentile for age and sex, and repeated 4 months later. Mean age was 9.4 + 1.1 years and weighed 52.4 + 13.3 kg. Body fat % (40.5 + 6.2 was determined by DXA (Hologic QDR 4500W. The protocol on the treadmill started with a warm up at 2.5 and 3 mph with a slope of 0% and 2%. The speed was kept at 3 mph for all the stages and the slope was increased 2% every 2 minutes. Statistical analysis (descriptive, t-test and ANOVAS 2x2x2 was done with SPSS 15.0. Results: Only 35% of the tests were maximal. The equation calculates was Y = 2.6x + 22.3 (x = protocol stage. Data pre and post treatment were not statistically different. Discussion: Increments in VO2 were consistent despite subject diversity (sex, % body fat, physical fitness, treatment. Conclusion: To be able to estimate VO2 at the different stages of the test without complex equipment or specialized staff, will facilitate the performance of stress tests on a daily basis.ResumenIntroducción: El consumo máximo de oxígeno (VO2 max está asociado con riesgos cardiovasculares y metabólicos pero resulta difícil valorarlo en niños y niñas obesos. El objetivo de este trabajo fue desarrollar una ecuación para estimar su VO2 (mL/kg/min y comprobar el porcentaje de pruebas máximas según los criterios recomendados. Métodos: Se analizaron las pruebas de esfuerzo de 222 sujetos (94 varones y 128 mujeres con un IMC superior al percentil 85 para su edad y sexo, y las repetidas a los 4 meses. Su edad era 9,4 + 1,1 años y pesaban 52,4 + 13,3 kg. El % de grasa corporal (40,5 + 6,2 se

  2. Cadmium uptake by plants

    Energy Technology Data Exchange (ETDEWEB)

    Haghiri, F.

    1973-01-01

    Absorption of /sup 115m/Cd by soybean (Gylcine max l.) plants via foliar and root systems and translocation into the seed was determined. The uptake of /sup 115m/Cd by soybeans via the root system was more efficient than that of the foliar placement. Growth and Cd concentrations of soybean and wheat (Triticum aestivum l.) tops were influenced by soil-applied Cd. In both crops, the Cd concentration of plant tops increased while yield decreased with increasing levels of applied Cd. Cadmium toxicitiy began to occur in both crops at the lowest level of soil applied Cd (2.5 ppM). With soybean plants, Cd toxicity symptoms resembled fe chlorosis. For wheat plants there were no visual symptoms other than the studied growth. The relative concentration of Cd found in several vegetable crops varied depending on the plant species. The relative Cd concentration in descending order for various vegetables was lettuce (Lactuca sativa l.) > radish top (Raphanus sativus l.) > celery stalk (Apium graveolens l.) > celery leaves greater than or equal to green pepper (Capsicum frutescens l.) > radish roots.

  3. Graded Exercise Testing in a Pediatric Weight Management Center: The DeVos Protocol.

    Science.gov (United States)

    Eisenmann, Joey C; Guseman, Emily Hill; Morrison, Kyle; Tucker, Jared; Smith, Lucie; Stratbucker, William

    2015-12-01

    In this article, we describe a protocol used to test the functional capacity of the obese pediatric patient and describe the peak oxygen consumption (VO2peak) of patients seeking treatment at a pediatric weight management center. One hundred eleven (mean age, 12.5 ± 3.0 years) patients performed a multistage exercise test on a treadmill, of which 90 (81%) met end-test criteria and provided valid VO2peak data. Peak VO2 was expressed: (1) in absolute terms (L·min(-1)); (2) as the ratio of the volume of oxygen consumed per minute relative to total body mass (mL·kg(-1)·min(-1)); and (3) as the ratio of the volume of oxygen consumed per minute relative to fat-free mass (mL·FFM·kg(-1)·min(-1)). Mean BMI z-score was 2.4 ± 0.3 and the mean percent body fat was 36.5 ± 9.7%. Absolute VO2peak (L·min(-1)) was significantly different between sexes; however, relative values were similar between sexes. Mean VO2peak was 25.7 ± 4.8 mL·kg(-1)·min(-1) with a range of 13.5-36.7 mL·kg(-1)·min(-1). Obese youth seeking treatment at a stage 3 pediatric weight management center exhibit low VO2peak. The protocol outlined here should serve as a model for similar programs interested in the submaximal and peak responses to exercise in obese pediatric patients.

  4. 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.

  5. Respiratory, cardiovascular and metabolic responses during different modes of overground bionic ambulation in persons with motor-incomplete spinal cord injury: A case series

    Directory of Open Access Journals (Sweden)

    Jochen Kressler

    2017-09-01

    Full Text Available Objective: To investigate the effects of overground bionic ambulation with variable assistance on cardiorespiratory and metabolic responses in persons with motor-incomplete spinal cord injury. Design: Case series. Subjects: Four participants with chronic, motor-incomplete spinal cord injury. Methods: Subjects completed a maximal graded exercise test on an arm-ergometer and 3 6-min bouts of overground bionic ambulation using different modes of assistance, i.e. Maximal, Adaptive, Fixed. Cardiorespiratory (oxygen consumption and metabolic (caloric expenditure and substrate utilization measures were taken using a mobile metabolic cart at each overground bionic ambulation assistance. Results: Cardiorespiratory responses ranged from low (24% VO2peak for the least impaired and fittest individual to supramaximal (124% VO2peak for the participant with the largest impairments and the lowest level of fitness. Different overground bionic ambulation assistive modes elicited small (3–8% VO2peak differences in cardiorespiratory responses for 3 participants. One participant had a large (28% VO2peak difference in cardiorespiratory responses to different modes of overground bionic ambulation. Metabolic responses mostly tracked closely with cardiorespiratory responses. Total energy expenditure ranged from 1.39 to 7.17 kcal/min. Fat oxidation ranged from 0.00 to 0.17 g/min across participants and different overground bionic ambulation modes. Conclusion: Overground bionic ambulation with variable assistance can substantially increase cardiorespiratory and metabolic responses; however, these responses vary widely across participants and overground bionic ambulation modes.

  6. Demonstration of the need for cardiovascular and pulmonary normative data for cancer survivors.

    Science.gov (United States)

    Schneider, C M; Repka, C P; Brown, J M; Lalonde, T L; Dallow, K T; Barlow, C E; Hayward, R

    2014-12-01

    Despite evidence that cancer and its treatments severely reduce cardiorespiratory fitness (CRF), normative data for cancer survivors do not exist. The present study identifies age and gender-specific CRF distributions in a cancer population. The use of cancer-specific normative CRF data may help stratify initial fitness status and assess improvements in response to exercise interventions in cancer survivors. Data from 703 cancer survivors were analyzed for this study. Quintiles were compiled for peak oxygen consumption (VO2peak), forced vital capacity (FVC), and forced expiratory volume (FEV1) for males and females in 5 age groups (19-39, 40-49, 50-59, 60-69, and ≥70 years of age). VO2peak values for the cancer population were significantly lower than the general US population. The cancer population average in each age group fell within the "very poor" classification of VO2peak values for the general population. FVC values in the cancer population were similar to the general population. Cancer survivors had very low age group-specific VO2peak values compared to the apparently healthy general US population. Previously, CRF values of cancer survivors were compared to normative values for the apparently healthy general population, which yielded imprecise classifications of initial fitness and changes in fitness, resulting in patient discouragement. © Georg Thieme Verlag KG Stuttgart · New York.

  7. Body acceleration distribution and O2 uptake in humans during running and jumping

    Science.gov (United States)

    Bhattacharya, A.; Mccutcheon, E. P.; Shvartz, E.; Greenleaf, J. E.

    1980-01-01

    The distribution of body acceleration and associated oxygen uptake and heart rate responses are investigated in treadmill running and trampoline jumping. Accelerations in the +Gz direction were measured at the lateral ankle, lumbosacral region and forehead of eight young men during level treadmill walking and running at four speeds and trampoline jumping at four heights, together with corresponding oxygen uptake and heart rate. With increasing treadmill speed, peak acceleration at the ankle is found always to exceed that at the back and forehead, and acceleration profiles with higher frequency components than those observed during jumping are observed. Acceleration levels are found to be more uniformly distributed with increasing height in jumping, although comparable oxygen uptake and heat rates are obtained. Results indicate that the magnitude of the biomechanical stimuli is greater in trampoline jumping than in running, which finding could be of use in the design of procedures to avert deconditioning in persons exposed to weightlessness.

  8. Rapid adaptation of activated sludge bacteria into a glycogen accumulating biofilm enabling anaerobic BOD uptake.

    Science.gov (United States)

    Hossain, Md Iqbal; Paparini, Andrea; Cord-Ruwisch, Ralf

    2017-03-01

    Glycogen accumulating organisms (GAO) are known to allow anaerobic uptake of biological oxygen demand (BOD) in activated sludge wastewater treatment systems. In this study, we report a rapid transition of suspended activated sludge biomass to a GAO dominated biofilm by selective enrichment using sequences of anaerobic loading followed by aerobic exposure of the biofilm to air. The study showed that within eight weeks, a fully operational, GAO dominated biofilm had developed, enabling complete anaerobic BOD uptake at a rate of 256mg/L/h. The oxygen uptake by the biofilm directly from the atmosphere had been calculated to provide significant energy savings. This study suggests that wastewater treatment plant operators can convert activated sludge systems readily into a "passive aeration" biofilm that avoids costly oxygen transfer to bulk wastewater solution. The described energy efficient BOD removal system provides an opportunity to be coupled with novel nitrogen removal processes such as anammox. Copyright © 2016. Published by Elsevier Ltd.

  9. Biological Oxygen Demand in Soils and Litters

    Science.gov (United States)

    Smagin, A. V.; Smagina, M. V.; Sadovnikova, N. B.

    2018-03-01

    Biological oxygen demand (BOD) in mineral and organic horizons of soddy-podzolic soils in the forest-park belt of Moscow as an indicator of their microbial respiration and potential biodestruction function has been studied. The BOD of soil samples has been estimated with a portable electrochemical analyzer after incubation in closed flasks under optimum hydrothermal conditions. A universal gradation scale of this parameter from very low (140 g O2/(m3 h)) has been proposed for mineral and organic horizons of soil. A physically substantiated model has been developed for the vertical distribution of BOD in the soil, which combines the diffusion transport of oxygen from the atmosphere and its biogenic uptake in the soil by the first-order reaction. An analytical solution of the model in the stationary state has been obtained; from it, the soil oxygen diffusivity and the kinetic constants of O2 uptake have been estimated, and the profile-integrated total BOD value has been calculated (0.4-1.8 g O2/(m2 h)), which is theoretically identical to the potential oxygen flux from the soil surface due to soil respiration. All model parameters reflect the recreation load on the soil cover by the decrease in their values against the control.

  10. Carbon mineralization and oxygen dynamics in sediments with deep oxygen penetration, Lake Superior

    DEFF Research Database (Denmark)

    Li, Jiying; Crowe, Sean Andrew; Miklesh, David

    2012-01-01

    To understand carbon and oxygen dynamics in sediments with deep oxygen penetration, we investigated eight locations (160–318-m depth) throughout Lake Superior. Despite the 2–4 weight percent organic carbon content, oxygen penetrated into the sediment by 3.5 to > 12 cm at all locations. Such deep ...... volume-specific carbon degradation rates were 0.3–1.5 µmol cm−3 d−1; bioturbation coefficient near the sediment surface was 3–8 cm2 yr−1. These results indicate that carbon cycling in large freshwater systems conforms to many of the same trends as in marine systems.......To understand carbon and oxygen dynamics in sediments with deep oxygen penetration, we investigated eight locations (160–318-m depth) throughout Lake Superior. Despite the 2–4 weight percent organic carbon content, oxygen penetrated into the sediment by 3.5 to > 12 cm at all locations. Such deep......, suggesting that temporal variability in deeply oxygenated sediments may be greater than previously acknowledged. The oxygen uptake rates (4.4–7.7 mmol m−2 d−1, average 6.1 mmol m−2 d−1) and carbon mineralization efficiency (∼ 90% of deposited carbon) were similar to those in marine hemipelagic and pelagic...

  11. Oxygen bubbling can improve the labelling of pentavalent technetium-99m dimercaptosuccinic acid

    International Nuclear Information System (INIS)

    Kobayashi, Hisataka; Suzuki, K.H.; Sakahara, Harumi; Yao Zhengsheng; Yokoyama, Akira; Konishi, Junji

    1995-01-01

    We performed studies in animals (mice) and humans to investigate the effect of such oxygen bubbling on the labelling efficiency of and on the renal uptake of 99m Tc. The method of labelling of 99m Tc (V) DMSA was that of Hirano. It was found that oxygen bubbling oxidized the contaminated 99m Tc (III) DMSA into 99m Tc (V) DMSA in vitro and decreased the uptake of radioactivity in the kidney in both amimals and humans. (orig.)

  12. Hollow Nanospheres with Fluorous Interiors for Transport of Molecular Oxygen in Water

    KAUST Repository

    Vu, Khanh B.

    2016-08-11

    A dispersion system for saturated fluorocarbon (SFC) liquids based on permeable hollow nanospheres with fluorous interiors is described. The nanospheres are well dispersible in water and are capable of immediate uptake of SFCs. The nanosphere shells are gas-permeable and feature reactive functional groups for easy modification of the exterior. These features make the SFC-filled nanospheres promising vehicles for respiratory oxygen storage and transport. Uptake of molecular oxygen into nanosphere-stabilized SFC dispersions is demonstrated.

  13. Technetium uptake by Sinapis Alba

    International Nuclear Information System (INIS)

    Mueller, H.; Ter Meer-Bekk, Ch.

    1986-01-01

    Transfer factors for pertechnetate uptake was determined for Sinapis Alba cultured hydroponically. For the freshly harvested, undried plants transfer factors were found between 13 and 40 depending on the growth period. (author)

  14. 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....

  15. Diselenolane-mediated cellular uptake.

    Science.gov (United States)

    Chuard, Nicolas; Poblador-Bahamonde, Amalia I; Zong, Lili; Bartolami, Eline; Hildebrandt, Jana; Weigand, Wolfgang; Sakai, Naomi; Matile, Stefan

    2018-02-21

    The emerging power of thiol-mediated uptake with strained disulfides called for a move from sulfur to selenium. We report that according to results with fluorescent model substrates, cellular uptake with 1,2-diselenolanes exceeds uptake with 1,2-dithiolanes and epidithiodiketopiperazines with regard to efficiency as well as intracellular localization. The diselenide analog of lipoic acid performs best. This 1,2-diselenolane delivers fluorophores efficiently to the cytosol of HeLa Kyoto cells, without detectable endosomal capture as with 1,2-dithiolanes or dominant escape into the nucleus as with epidithiodiketopiperazines. Diselenolane-mediated cytosolic delivery is non-toxic (MTT assay), sensitive to temperature but insensitive to inhibitors of endocytosis (chlorpromazine, methyl-β-cyclodextrin, wortmannin, cytochalasin B) and conventional thiol-mediated uptake (Ellman's reagent), and to serum. Selenophilicity, the extreme CSeSeC dihedral angle of 0° and the high but different acidity of primary and secondary selenols might all contribute to uptake. Thiol-exchange affinity chromatography is introduced as operational mimic of thiol-mediated uptake that provides, in combination with rate enhancement of DTT oxidation, direct experimental evidence for existence and nature of the involved selenosulfides.

  16. Factors influencing the in vitro uptake of mercury vapour in blood

    Energy Technology Data Exchange (ETDEWEB)

    Kudsk, F.N.

    1969-01-01

    The influence of a number of factors on the in vitro uptake of mercury vapour in blood has been investigated in order to clarify the mechanism by which mercury is oxidized in blood. The rate of mercury uptake in blood in a pure oxygen atmosphere is moderately increased, but somewhat decreased in a nitrogen atmosphere when compared with the rate of uptake in an atmospheric air phase. Increasing concentrations of methylene blue induce a very pronounced acceleration of the rate of mercury uptake in blood up to a maximum of about 10 times the normal uptake in an atmospheric air phase. Menadione shows a similar, but even more pronounced effect. The menadione-stimulated uptake is markedly inhibited by low concentrations of ethyl alcohol. Concentrations of potassium cyanide from 1/8 x 10/sup -3/ to 4 x 10/sup -3/ M cause a progressive inhibition of the mercury uptake in the blood up to a maximum of about 60%, which is very similar to the effect produced by ethyl alcohol. The investigations point to hydrogen peroxide and oxidized glutathione as agents of importance in the oxidation and uptake of mercury vapour in blood. The way in which ethyl alcohol inhibits the uptake is still unknown. Some possible mechanisms are discussed. 24 references, 4 figures, 3 tables.

  17. Relationship between oxygen concentration, respiration and filtration rate in blue mussel Mytilus edulis

    Science.gov (United States)

    Tang, Baojun; Riisgård, Hans Ulrik

    2018-03-01

    The large water-pumping and particle-capturing gills of the filter-feeding blue mussel Mytilus edulis are oversized for respiratory purposes. Consequently, the oxygen uptake rate of the mussel has been suggested to be rather insensitive to decreasing oxygen concentrations in the ambient water, since the diffusion rate of oxygen from water flowing through the mussel determines oxygen uptake. We tested this hypothesis by measuring the oxygen uptake in mussels exposed to various oxygen concentrations. These concentrations were established via N2-bubbling of the water in a respiration chamber with mussels fed algal cells to stimulate fully opening of the valves. It was found that mussels exposed to oxygen concentrations decreasing from 9 to 2 mg O2/L resulted in a slow but significant reduction in the respiration rate, while the filtration rate remained high and constant. Thus, a decrease of oxygen concentration by 78% only resulted in a 25% decrease in respiration rate. However, at oxygen concentrations below 2 mg O2/L M. edulis responded by gradually closing its valves, resulting in a rapid decrease of filtration rate, concurrent with a rapid reduction of respiration rate. These observations indicated that M. edulis is no longer able to maintain its normal aerobic metabolism at oxygen concentration below 2 mg O2/L, and there seems to be an energy-saving mechanism in bivalve molluscs to strongly reduce their activity when exposed to low oxygen conditions.

  18. Comparação entre diferentes métodos de análise do componente lento do consumo de oxigênio: uma abordagem no domínio muito intenso de exercício Comparison between different methods of analysis of slow component of oxygen uptake: a view in severe exercise domain

    Directory of Open Access Journals (Sweden)

    Marcos G. Santana

    2007-08-01

    Full Text Available O objetivo do presente estudo foi comparar, em domínio muito intenso de exercício, diferentes técnicas utilizadas para medir a amplitude do componente lento (CL da cinética do consumo de oxigênio. Dez ciclistas treinados, do gênero masculino [média ± DP (idade: 25 ± 3,6 anos, massa corporal: 67,2 ± 4,5kg, altura: 174,8 ± 6,5cm e VO2max: 62,4 ± 3,1ml.kg¹.min¹], realizaram duas idênticas transições de carga constante (intensidade de 75%delta: 75% da diferença entre o VO2 no limiar de lactato e o VO2max em dias diferentes. O CL foi calculado a partir de diferentes métodos: (1 modelo biexponencial [VO2(t = VO2base + A1 (1 e-(t-TA1/t1 + A2 (1 e(tTA2/t2], (2 intervalos predeterminados (o deltaVO26-2: diferença do VO2 entre o segundo e o sexto minuto de exercício e o deltaVO263: diferença do VO2 entre o terceiro e o sexto minuto de exercício e (3 diferença entre o VO2 obtido no final do exercício e o valor obtido a partir de um ajuste monoexponencial do "componente primário" (tempo predeterminado de 120s (CL6"CP". Todos os métodos foram comparados entre si. Os resultados demonstraram significante subestimação do CL obtido pelo método de intervalos predeterminados (deltaVO26-2: 432 ± 126ml.min¹ e deltaVO263: 279 ± 88ml.min¹ quando comparado com o modelo biexponencial (676 ± 136ml.min¹ e ao CL6"CP" [(719 ± 265ml.min¹ (p The objective of the present study was to compare in severe exercise domain, different techniques used for measuring the amplitude of the slow component (SC of oxygen uptake kinetics. Ten trained cyclists, male (age: 25 ± 3.6 years, body mass: 67.2 ± 4.5 kg, height: 174.8 ± 6.5 cm and VO2max: 62.4 ± 3.1 mL.kg¹.min¹, performed two identical bouts transitions at constant load [mean ± SD (intensity 75%delta: 75% of the difference between the VO2 lactate threshold and the VO2max] in different days. The SC was calculated from different methods: (1 bi-exponential model [VO2(t = VO2base + A1 (1 e(tTA1

  19. Respiratory physiology of vertebrates: life with and without oxygen

    National Research Council Canada - National Science Library

    Nilsson, Göran E

    2010-01-01

    ... sensing, uptake and transport in a textbook style. Subsequently, the reader is shown important examples of extreme respiratory performance, such as diving and high-altitude survival in mammals and birds, air breathing in fish, and those few vertebrates that can survive without any oxygen at all for several months, showing how evolution has s...

  20. Oxygen penetration around burrows and roots in aquatic sediments

    DEFF Research Database (Denmark)

    Meysman, Filip J.R.; Galaktionov, O.S.; Glud, Ronnie N.

    2010-01-01

    Diffusion is the dominant physical mechanism for the transfer of oxygen into fine-grained aquatic sediments. This diffusive uptake occurs at the sediment-water interface, but also at internal interfaces, such as along ventilated burrows or O2 releasing plant roots. Here, we present a systematic...

  1. Root uptake of transuranic elements

    International Nuclear Information System (INIS)

    Schulz, R.K.

    1977-01-01

    The uptake of elements by plant roots is one of the important pathways of entry of many elements into the food chain of man. Data are cited showing plutonium concentration ratios, plant/soil, ranging from 10 -10 to 10 -3 . Concentration ratios for americium range from 10 -7 to 10 +1 . Limited experiments with curium and neptunium indicate that root uptake of curium is similar to that of americium and that plant uptake of neptunium is substantially larger than that of curium and americium. The extreme ranges of concentration ratios cited for plutonium and americium are due to a number of causes. Experimental conditions such as very intensive cropping will lead to abnormally high concentration ratios. In some experiments, addition of chelating agents markedly increased plant root uptake of transuranic elements. Particle size and composition of the source material influenced uptake of the transuranics by plants. Translocation within the plant, and soil factors such as pH and organic matter content, all affect concentration ratios

  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. Validation and Refinement of Prediction Models to Estimate Exercise Capacity in Cancer Survivors Using the Steep Ramp Test.

    Science.gov (United States)

    Stuiver, Martijn M; Kampshoff, Caroline S; Persoon, Saskia; Groen, Wim; van Mechelen, Willem; Chinapaw, Mai J M; Brug, Johannes; Nollet, Frans; Kersten, Marie-José; Schep, Goof; Buffart, Laurien M

    2017-11-01

    To further test the validity and clinical usefulness of the steep ramp test (SRT) in estimating exercise tolerance in cancer survivors by external validation and extension of previously published prediction models for peak oxygen consumption (Vo 2peak ) and peak power output (W peak ). Cross-sectional study. Multicenter. Cancer survivors (N=283) in 2 randomized controlled exercise trials. Not applicable. Prediction model accuracy was assessed by intraclass correlation coefficients (ICCs) and limits of agreement (LOA). Multiple linear regression was used for model extension. Clinical performance was judged by the percentage of accurate endurance exercise prescriptions. ICCs of SRT-predicted Vo 2peak and W peak with these values as obtained by the cardiopulmonary exercise test were .61 and .73, respectively, using the previously published prediction models. 95% LOA were ±705mL/min with a bias of 190mL/min for Vo 2peak and ±59W with a bias of 5W for W peak . Modest improvements were obtained by adding body weight and sex to the regression equation for the prediction of Vo 2peak (ICC, .73; 95% LOA, ±608mL/min) and by adding age, height, and sex for the prediction of W peak (ICC, .81; 95% LOA, ±48W). Accuracy of endurance exercise prescription improved from 57% accurate prescriptions to 68% accurate prescriptions with the new prediction model for W peak . Predictions of Vo 2peak and W peak based on the SRT are adequate at the group level, but insufficiently accurate in individual patients. The multivariable prediction model for W peak can be used cautiously (eg, supplemented with a Borg score) to aid endurance exercise prescription. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  7. [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.

  8. 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

  9. Denitrifying bacterial community composition changes associated with stages of denitrification in oxygen minimum zones

    Digital Repository Service at National Institute of Oceanography (India)

    Jayakumar, D.A; O'Mullan, G.D.; Naqvi, S.W.A.; Ward, B.B.

    in the ocean. Nature 445:163–167 11. Devol AH (1978) Bacterial oxygen uptake kinetics as related to biological processes in oxygen deficient zones of the oceans. Deep-Sea Res 25:137–146 12. Devol AH, Uhlenhopp AG, Naqvi SWA, Brandes JA, Jayakumar DA, Naik H...

  10. Muscle oxygen kinetics at onset of intense dynamic exercise in humans

    DEFF Research Database (Denmark)

    Bangsbo, J; Krustrup, P; González-Alonso, J

    2000-01-01

    The present study examined the onset and the rate of rise of muscle oxidation during intense exercise in humans and whether oxygen availability limits muscle oxygen uptake in the initial phase of intense exercise. Six subjects performed 3 min of intense one-legged knee-extensor exercise [65.3 +/-...

  11. Inferring foliar water uptake using stable isotopes of water.

    Science.gov (United States)

    Goldsmith, Gregory R; Lehmann, Marco M; Cernusak, Lucas A; Arend, Matthias; Siegwolf, Rolf T W

    2017-08-01

    A growing number of studies have described the direct absorption of water into leaves, a phenomenon known as foliar water uptake. The resultant increase in the amount of water in the leaf can be important for plant function. Exposing leaves to isotopically enriched or depleted water sources has become a common method for establishing whether or not a plant is capable of carrying out foliar water uptake. However, a careful inspection of our understanding of the fluxes of water isotopes between leaves and the atmosphere under high humidity conditions shows that there can clearly be isotopic exchange between the two pools even in the absence of a change in the mass of water in the leaf. We provide experimental evidence that while leaf water isotope ratios may change following exposure to a fog event using water with a depleted oxygen isotope ratio, leaf mass only changes when leaves are experiencing a water deficit that creates a driving gradient for the uptake of water by the leaf. Studies that rely on stable isotopes of water as a means of studying plant water use, particularly with respect to foliar water uptake, must consider the effects of these isotopic exchange processes.

  12. Interaction between age and aerobic fitness in determining heart rate dynamics

    International Nuclear Information System (INIS)

    McNarry, M A; Lewis, M J

    2012-01-01

    Heart rate variability (HRV) and phase-rectified signal averaging (PRSA) estimates of heart rate dynamics are diminished in older people compared with younger people. However, it is not fully elucidated whether these differences are related to age per se or to the concomitant influence of aerobic fitness. Aerobic fitness (peak oxygen uptake, gas exchange threshold, oxygen uptake kinetics, exercise economy) was assessed in 70 healthy adults (41 male) aged 18–57 years. Participants also underwent a 24 h, ambulatory ECG for the derivation of HRV and PRSA variables. HRV was most sensitive to age and aerobic fitness when measured during the morning period (6 am–12 pm). HRV and PRSA were both diminished with age and were higher in aerobically superior participants. The decline in HRV with age was predominantly attributable to age itself (33%), with aerobic fitness representing an additional modulating factor. The present study also provides tentative evidence that assessment of the influence of aerobic fitness should not rely on .VO 2peak alone. These findings demonstrate that age per se is an important factor in determining HRV. However, given the clinical importance of diminished HRV and the immutable nature of aging, the potential significance of physical activity/training to enhance cardiac regulatory function should not be underestimated. (paper)

  13. Nonparetic Knee Extensor Strength Is the Determinant of Exercise Capacity of Community-Dwelling Stroke Survivors

    Directory of Open Access Journals (Sweden)

    Wei-Te Wang

    2014-01-01

    Full Text Available Objective. To investigate the relationship among walking speed, exercise capacity, and leg strength in community dwelling stroke subjects and to evaluate which one was the leading determinant factor of them. Design. This is a descriptive, cross-sectional study. Thirty-five chronic stroke patients who were able to walk independently in their community were enrolled. Walking speed was evaluated by using the 12-meter walking test. A maximal exercise test was used to determine the stroke subjects’ exercise capacity. Knee extensor strength, measured as isokinetic torque, was assessed by isokinetic dynamometer. Results. The main walking speed of our subjects was 0.52 m/s. Peak oxygen uptake (VO2 peak was 1.21±0.43 L/min. Knee extensor strength, no matter whether paretic or nonparetic side, was significantly correlated to 12-meter walking speed and exercise capacity. Linear regression also showed the strength of the affected knee extensor was the determinant of walking speed and that of the nonparetic knee extensor was the determinant of exercise capacity in community dwelling stroke subjects. Conclusions. Walking speed and peak oxygen uptake were markedly decreased after stroke. Knee extensor strength of nonparetic leg was the most important determinant of exercise capacity of the community-dwelling stroke subjects. Knee extensor strengthening should be emphasized to help stroke patient to achieve optimal community living.

  14. 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

  15. Hg uptake in ureteral obstructions

    International Nuclear Information System (INIS)

    Desgrez, J.P.; Bourguignon, M.; Raynaud, C.; CEA, 91 - Orsay

    1976-01-01

    In the presence of a total obstruction the results obtained with the Hg uptake test, as indeed with other functional tests, inform on the value of the kidney function at the time but have no prognostic value where repair possibilities are concerned. Some preliminary results seem to show however that very soon after the obstacle is removed, by the 10th or 15th day perhaps, quantitative functional tests may once more be used to evaluate the functional prognosis. This would mean that by waiting about two weeks after the disappearance of a total obstruction the Hg uptake test may again be used in all confidence. In order to check this deduction, which is based on slender evidence but which nevertheless has important practical implications, the measurement of the Hg uptake rate during the days following removal of the obstacle appears essential. In long-standing partial obstructions the Hg uptake rate gives an accurate assessment of the functional balance and helps considerably in the choice of therapy [fr

  16. Cellular uptake of metallated cobalamins

    DEFF Research Database (Denmark)

    Tran, Mai Thanh Quynh; Stürup, Stefan; Lambert, Ian Henry

    2016-01-01

    Cellular uptake of vitamin B12-cisplatin conjugates was estimated via detection of their metal constituents (Co, Pt, and Re) by inductively coupled plasma mass spectrometry (ICP-MS). Vitamin B12 (cyano-cob(iii)alamin) and aquo-cob(iii)alamin [Cbl-OH2](+), which differ in the β-axial ligands (CN...

  17. Tumor uptake of radioruthenium compounds

    International Nuclear Information System (INIS)

    Srivastava, S.C.; Richards, P.; Meinken, G.E.; Larson, S.M.; Grunbaum, Z.

    1980-01-01

    The use of ruthenium-97 as a scintigraphic agent, particularly for tumor localization, is investigated. The tumor uptake of ruthenium chloride and ruthenium-labelled transferrin is evaluated and their application as tumor-imagine agents is compared to gallium-67 citrate

  18. Octreotide Uptake in Parathyroid Adenoma

    Directory of Open Access Journals (Sweden)

    Seyhan Karaçavuş

    2012-08-01

    Full Text Available The patient with a history of bone pain and muscle weakness, was thought to have oncogenic osteomalacia as a result of biochemical investigations and directed to Nuclear Medicine Department for a whole-body bone scintigraphy and 111In-octreotide scintigraphy. There was no focal pathologic tracer uptake, but generalized marked increase in skeletal uptake on bone scintigraphy. Octreotide scintigraphy showed accumulation of octreotide in the region of the left lobe of the thyroid gland in the neck. Thereafter, parathyroid scintigraphy was performed with technetium-99m labeled metroxy-isobutyl-isonitryl (99mTc-MIB and MIBI scan demonstrated radiotracer uptake at the same location with octreotide scintigraphy. The patient underwent left inferior parathyroidectomy and histopathology confirmed a parathyroid adenoma. Somatostatin receptor positive parathyroid adenoma may show octreotide uptake. Octreotide scintigraphy may be promising and indicate a possibility of using somatostatin analogues for the medical treatment of somatostatin receptor positive parathyroid tumors. (MIRT 2012;21:77-79

  19. Ocean carbon uptake and storage

    International Nuclear Information System (INIS)

    Tilbrook, Bronte

    2007-01-01

    Full text: The ocean contains about 95% of the carbon in the atmosphere, ocean and land biosphere system, and is of fundamental importance in regulating atmospheric carbon dioxide concentrations. In the 1990s an international research effort involving Australia was established to determine the uptake and storage of anthropogenic C02 for all major ocean basins. The research showed that about 118 of the 244 + 20 billion tons of the anthropogenic carbon emitted through fossil fuel burning and cement production has been stored in the ocean since preindustrial times, thus helping reduce the rate of increase in atmospheric C02. The research also showed the terrestrial biosphere has been a small net source of C02 (39 ± 28 billion tons carbon) to the atmosphere over the same period. About 60% of the total ocean inventory of the anthropogenic C02 was found in the Southern Hemisphere, with most in the 30 0 S to 50 0 S latitude band. This mid-latitude band is where surface waters are subducted as Mode and Intermediate waters, which is a major pathway controlling ocean C02 uptake. High storage (23% of the total) also occurs in the North Atlantic, associated with deep water formation in that basin. The ocean uptake and storage is expected to increase in the coming decades as atmospheric C02 concentrations rise. However, a number of feedback mechanisms associated with surface warming, changes in circulation, and biological effects are likely to impact on the uptake capacity. The accumulation or storage-of the C02 in the ocean is also the major driver of ocean acidification with potential to disrupt marine ecosystems. This talk will describe the current understanding of the ocean C02 uptake and storage and a new international research strategy to detect how the ocean uptake and storage will evolve on interannual through decadal scales. Understanding the ocean response to increasing atmospheric C02 will be a key element in managing future C02 increases and establishing

  20. Impacts of EDTA on Uptake and Accumulation of Cu2+ by Spinach ...

    African Journals Online (AJOL)

    MBI

    2017-06-05

    Jun 5, 2017 ... INTRODUCTION. Copper is an essential micronutrient in plants. It plays a significant ... reactive oxygen species (ROS) and free radicals. (Erdei et al., 2002; .... higher levels of applied Cu2+ enhanced the uptake of the ion by ...

  1. Batch culture of Azotobacter vinelandii under oxygen limitation conditionS

    Energy Technology Data Exchange (ETDEWEB)

    Camacho Rubio, F.; Martinez Nieto, L.; Fernandez Serrano, M.; Jimenez Moleon, M.C. [Departamento de Ingenieria Quimica, Universidad de Granada, Granada (Spain)

    1996-12-01

    The batch culture of Azotobacter vinealandii on glucose under nitrogen-fixing conditions, seeking oxygen limitation conditions, has been studied in order to use it as a Biological Test System for the experimental study of oxygen transfer enhancement methods in aerobic fermenters. overall kinetic parameters for exponential growth and for linear growth (under oxygen limitation) have been determined. It was noted an appreciable influence of the oxygen transfer rate on glucose and oxygen uptake, which seems to be due to alginate production, excreted as a nitrogenase protection mechanisms. (Author) 12 refs.

  2. Singlet Oxygen Sensor Green: Photochemical Behavior in Solution and in a Mammalian Cell

    DEFF Research Database (Denmark)

    Gollmer, Anita; Arnbjerg, Jacob; Blaikie, Frances Helen

    2011-01-01

    The development of efficient and selective luminescent probes for reactive oxygen species, particularly for singlet molecular oxygen, is currently of great importance. In this study, the photochemical behavior of Singlet Oxygen Sensor Green® (SOSG), a commercially available fluorescent probe...... of the reaction between SOSG and singlet oxygen is, itself, an efficient singlet oxygen photosensitizer. Second, SOSG appears to efficiently bind to proteins which, in turn, can influence uptake by a cell as well as behavior in the cell. As such, incorrect use of SOSG can yield misleading data on yields...

  3. FDG uptake in the stomach

    International Nuclear Information System (INIS)

    Yun, M. J.; Cho, H. J.; Cho, E. H.; Kim, T. S.; Kang, W. J.; Lee, J. D.

    2007-01-01

    This study was performed to evaluate histopathologic features of advanced gastric cancer (AGC) to predict FDG uptake on PET. 153 patients(102 men; mean age, 55 y) were diagnosed with AGC by surgery were included in this study. PET images were evaluated by visual and semi-quantitative analysis of FDG uptake in primary tumors. Primary tumors size were measured and divided according to Borrmann classification. Tumor histology was classified under WHO classification, depth of invasion and Iymphovascular invasion. The tumors were also grouped by high cellular(cellularity = 50%) and low cellular group (<50%). Microscopic growth type was based on Lauren classification. Stromal fibrosis degree and inflammatory cell infiltration amount was graded as low(none∼mild), or high(moderate∼severe). Lymph node metastases was assessed in all patients. Statistical analyses were performed to evaluate differences in SUV as to histopathologic factors. Of the 153 patients, 21 patients(14%) had primary tumor invisible on initial whole body images. After water ingestion, the tumors became visible in 15 of the 21 patients due to disappearance of physiologic stomach uptake. Polypoid or ulcerofungating tumors, high cellularity, intestinal growth pattern, and larger tumors significantly predicted increased tumor SUVs. Well or moderately differentiated adenocarcinoma tended to show high cellularity and intestinal growth pattern. Poorly differentiated adenocarcinoma had diverse spectrum of histopathology. Signet ring cell carcinomas were mostly ulceroinfiltrative or diffusely infiltrative in macroscopic type and diffuse in microscopic tumor growth. Mucinous adenocarcinomas were mostly low in cellularity. FDG uptake patterns are useful in representing histopathologic characteristics of the entire tumor in gastric cancers. The degree of FDG uptake depends on tumor size, macroscopic type, cellularity, and microscopic growth pattern and it shows no association with well known important prognostic

  4. Integrated turbomachine oxygen plant

    Science.gov (United States)

    Anand, Ashok Kumar; DePuy, Richard Anthony; Muthaiah, Veerappan

    2014-06-17

    An integrated turbomachine oxygen plant includes a turbomachine and an air separation unit. One or more compressor pathways flow compressed air from a compressor through one or more of a combustor and a turbine expander to cool the combustor and/or the turbine expander. An air separation unit is operably connected to the one or more compressor pathways and is configured to separate the compressed air into oxygen and oxygen-depleted air. A method of air separation in an integrated turbomachine oxygen plant includes compressing a flow of air in a compressor of a turbomachine. The compressed flow of air is flowed through one or more of a combustor and a turbine expander of the turbomachine to cool the combustor and/or the turbine expander. The compressed flow of air is directed to an air separation unit and is separated into oxygen and oxygen-depleted air.

  5. Ambient oxygen promotes tumorigenesis.

    Directory of Open Access Journals (Sweden)

    Ho Joong Sung

    2011-05-01

    Full Text Available Oxygen serves as an essential factor for oxidative stress, and it has been shown to be a mutagen in bacteria. While it is well established that ambient oxygen can also cause genomic instability in cultured mammalian cells, its effect on de novo tumorigenesis at the organismal level is unclear. Herein, by decreasing ambient oxygen exposure, we report a ∼50% increase in the median tumor-free survival time of p53-/- mice. In the thymus, reducing oxygen exposure decreased the levels of oxidative DNA damage and RAG recombinase, both of which are known to promote lymphomagenesis in p53-/- mice. Oxygen is further shown to be associated with genomic instability in two additional cancer models involving the APC tumor suppressor gene and chemical carcinogenesis. Together, these observations represent the first report directly testing the effect of ambient oxygen on de novo tumorigenesis and provide important physiologic evidence demonstrating its critical role in increasing genomic instability in vivo.

  6. Preliminary Study of Oxygen-Enhanced Longitudinal Relaxation in MRI: A Potential Novel Biomarker of Oxygenation Changes in Solid Tumors

    International Nuclear Information System (INIS)

    O'Connor, James P.B.; Naish, Josephine H.; Parker, Geoff J.M.; Waterton, John C.; Watson, Yvonne; Jayson, Gordon C.; Buonaccorsi, Giovanni A.; Cheung, Sue; Buckley, David L.; McGrath, Deirdre M.; West, Catharine M.L.; Davidson, Susan E.; Roberts, Caleb; Mills, Samantha J.; Mitchell, Claire L.; Hope, Lynn; Ton, N. Chan; Jackson, Alan

    2009-01-01

    Purpose: There is considerable interest in developing non-invasive methods of mapping tumor hypoxia. Changes in tissue oxygen concentration produce proportional changes in the magnetic resonance imaging (MRI) longitudinal relaxation rate (R 1 ). This technique has been used previously to evaluate oxygen delivery to healthy tissues and is distinct from blood oxygenation level-dependent (BOLD) imaging. Here we report application of this method to detect alteration in tumor oxygenation status. Methods and materials: Ten patients with advanced cancer of the abdomen and pelvis underwent serial measurement of tumor R 1 while breathing medical air (21% oxygen) followed by 100% oxygen (oxygen-enhanced MRI). Gadolinium-based dynamic contrast-enhanced MRI was then performed to compare the spatial distribution of perfusion with that of oxygen-induced ΔR 1 . Results: ΔR 1 showed significant increases of 0.021 to 0.058 s -1 in eight patients with either locally recurrent tumor from cervical and hepatocellular carcinomas or metastases from ovarian and colorectal carcinomas. In general, there was congruency between perfusion and oxygen concentration. However, regional mismatch was observed in some tumor cores. Here, moderate gadolinium uptake (consistent with moderate perfusion) was associated with low area under the ΔR 1 curve (consistent with minimal increase in oxygen concentration). Conclusions: These results provide evidence that oxygen-enhanced longitudinal relaxation can monitor changes in tumor oxygen concentration. The technique shows promise in identifying hypoxic regions within tumors and may enable spatial mapping of change in tumor oxygen concentration.

  7. Arsenic uptake in bacterial calcite

    Science.gov (United States)

    Catelani, Tiziano; Perito, Brunella; Bellucci, Francesco; Lee, Sang Soo; Fenter, Paul; Newville, Matthew; Rimondi, Valentina; Pratesi, Giovanni; Costagliola, Pilario

    2018-02-01

    Bio-mediated processes for arsenic (As) uptake in calcite were investigated by means of X-ray Diffraction (XRD) and X-ray Absorption Spectroscopy (XAS) coupled with X-ray Fluorescence measurements. The environmental bacterial strain Bacillus licheniformis BD5, sampled at the Bullicame Hot Springs (Viterbo, Central Italy), was used to synthesize calcite from As-enriched growth media. Both liquid and solid cultures were applied to simulate planktonic and biofilm community environments, respectively. Bacterial calcite samples cultured in liquid media had an As enrichment factor (Kd) 50 times higher than that from solid media. The XRD analysis revealed an elongation of the crystal lattice along the c axis (by 0.03 Å) for biogenic calcite, which likely resulted from the substitution of larger arsenate for carbonate in the crystal. The XAS data also showed a clear difference in the oxidation state of sorbed As between bacterial and abiotic calcite. Abiotic chemical processes yielded predominantly As(V) uptake whereas bacterial precipitation processes led to the uptake of both As(III) and As(V). The presence of As(III) in bacterial calcite is proposed to result from subsequent reduction of arsenate to arsenite by bacterial activities. To the best of our knowledge, this is the first experimental observation of the incorporation of As(III) in the calcite crystal lattice, revealing a critical role of biochemical processes for the As cycling in nature.

  8. Arsenic uptake in bacterial calcite

    Energy Technology Data Exchange (ETDEWEB)

    Catelani, Tiziano; Perito, Brunella; Bellucci, Francesco; Lee, Sang Soo; Fenter, Paul; Newville, Matthew G.; Rimondi, Valentina; Pratesi, Giovanni; Costagliola, Pilario

    2018-02-01

    Bio-mediated processes for arsenic (As) uptake in calcite were investigated by means of X-ray Diffraction (XRD) and Xray Absorption Spectroscopy (XAS) coupled with X-ray Fluorescence measurements. The environmental bacterial strain Bacillus licheniformis BD5, sampled at the Bullicame Hot Springs (Viterbo, Central Italy), was used to synthesize calcite from As-enriched growth media. Both liquid and solid cultures were applied to simulate planktonic and biofilm community environments, respectively. Bacterial calcite samples cultured in liquid media had an As enrichment factor (Kd) 50 times higher than that from solid media. The XRD analysis revealed an elongation of the crystal lattice along the c axis (by 0.03Å) for biogenic calcite, which likely resulted from the substitution of larger arsenate for carbonate in the crystal. The XAS data also showed a clear difference in the oxidation state of sorbed As between bacterial and abiotic calcite. Abiotic chemical processes yielded predominantly As(V) uptake whereas bacterial precipitation processes led to the uptake of both As(III) and As(V). The presence of As(III) in bacterial calcite is proposed to result from subsequent reduction of arsenate to arsenite by bacterial activities. To the best of our knowledge, this is the first experimental observation of the incorporation of As(III) in the calcite crystal lattice, revealing a critical role of biochemical processes for the As cycling in nature.

  9. Radiation increases the cellular uptake of exosomes through CD29/CD81 complex formation

    International Nuclear Information System (INIS)

    Hazawa, Masaharu; Tomiyama, Kenichi; Saotome-Nakamura, Ai; Obara, Chizuka; Yasuda, Takeshi; Gotoh, Takaya; Tanaka, Izumi; Yakumaru, Haruko; Ishihara, Hiroshi; Tajima, Katsushi

    2014-01-01

    Highlights: • Radiation increases cellular uptake of exosomes. • Radiation induces colocalization of CD29 and CD81. • Exosomes selectively bind the CD29/CD81 complex. • Radiation increases the cellular uptake of exosomes through CD29/CD81 complex formation. - Abstract: Exosomes mediate intercellular communication, and mesenchymal stem cells (MSC) or their secreted exosomes affect a number of pathophysiologic states. Clinical applications of MSC and exosomes are increasingly anticipated. Radiation therapy is the main therapeutic tool for a number of various conditions. The cellular uptake mechanisms of exosomes and the effects of radiation on exosome–cell interactions are crucial, but they are not well understood. Here we examined the basic mechanisms and effects of radiation on exosome uptake processes in MSC. Radiation increased the cellular uptake of exosomes. Radiation markedly enhanced the initial cellular attachment to exosomes and induced the colocalization of integrin CD29 and tetraspanin CD81 on the cell surface without affecting their expression levels. Exosomes dominantly bound to the CD29/CD81 complex. Knockdown of CD29 completely inhibited the radiation-induced uptake, and additional or single knockdown of CD81 inhibited basal uptake as well as the increase in radiation-induced uptake. We also examined possible exosome uptake processes affected by radiation. Radiation-induced changes did not involve dynamin2, reactive oxygen species, or their evoked p38 mitogen-activated protein kinase-dependent endocytic or pinocytic pathways. Radiation increased the cellular uptake of exosomes through CD29/CD81 complex formation. These findings provide essential basic insights for potential therapeutic applications of exosomes or MSC in combination with radiation

  10. Hyperoxia increases the uptake of 5-fluorouracil in mammary tumors independently of changes in interstitial fluid pressure and tumor stroma

    Directory of Open Access Journals (Sweden)

    Salvesen Gerd S

    2009-12-01

    Full Text Available Abstract Background Hypoxia is associated with increased resistance to chemo- and radiation-therapy. Hyperoxic treatment (hyperbaric oxygen has previously been shown to potentiate the effect of some forms of chemotherapy, and this has been ascribed to enhanced cytotoxicity or neovascularisation. The aim of this study was to elucidate whether hyperoxia also enhances any actual uptake of 5FU (5-fluorouracil into the tumor tissue and if this can be explained by changes in the interstitium and extracellular matrix. Methods One group of tumor bearing rats was exposed to repeated hyperbaric oxygen (HBO treatment (2 bar, pO2 = 2 bar, 4 exposures à 90 min, whereas one group was exposed to one single identical HBO treatment. Animals housed under normal atmosphere (1 bar, pO2 = 0.2 bar served as controls. Three doses of 5FU were tested for dose response. Uptake of [3H]-5FU in the tumor was assessed, with special reference to factors that might have contributed, such as interstitial fluid pressure (Pif, collagen content, oxygen stress (measured as malondialdehyd levels, lymphatics and transcapillary transport in the tumors. Results The uptake of the cytostatic agent increases immediately after a single HBO treatment (more than 50%, but not 24 hours after the last repeated HBO treatment. Thus, the uptake is most likely related to the transient increase in oxygenation in the tumor tissue. Factors like tumor Pif and collagen content, which decreased significantly in the tumor interstitium after repeated HBO treatment, was without effect on the drug uptake. Conclusion We showed that hyperoxia increases the uptake of [3H]-5FU in DMBA-induced mammary tumors per se, independently of changes in Pif, oxygen stress, collagen fibril density, or transendothelial transport alone. The mechanism by which such an uptake occur is still not elucidated, but it is clearly stimulated by elevated pO2.

  11. Plant uptake of dual-labeled organic N biased by inorganic C uptake

    DEFF Research Database (Denmark)

    Rasmussen, Jim; Sauheitl, Leopold; Eriksen, Jørgen

    2010-01-01

    glycine or CO2-3 , but found no differences in uptake rates between these C-sources. The uptake of inorganic C to the shoot tissue was higher for maize grown in full light compared to shading, which indicates a passive uptake of inorganic C with water. We conclude that uptake of inorganic C produced...

  12. Oxygen enrichment incineration

    International Nuclear Information System (INIS)

    Kim, Jeong Guk; Yang, Hee Chul; Park, Geun Il; Kim, Joon Hyung

    2000-10-01

    Oxygen enriched combustion technology has recently been used in waste incineration. To apply the oxygen enrichment on alpha-bearing waste incineration, which is being developed, a state-of-an-art review has been performed. The use of oxygen or oxygen-enriched air instead of air in incineration would result in increase of combustion efficiency and capacity, and reduction of off-gas product. Especially, the off-gas could be reduced below a quarter, which might reduce off-gas treatment facilities, and also increase an efficiency of off-gas treatment. However, the use of oxygen might also lead to local overheating and high nitrogen oxides (NOx) formation. To overcome these problems, an application of low NOx oxy-fuel burner and recycling of a part of off-gas to combustion chamber have been suggested

  13. Oxygen enrichment incineration

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong Guk; Yang, Hee Chul; Park, Geun Il; Kim, Joon Hyung

    2000-10-01

    Oxygen enriched combustion technology has recently been used in waste incineration. To apply the oxygen enrichment on alpha-bearing waste incineration, which is being developed, a state-of-an-art review has been performed. The use of oxygen or oxygen-enriched air instead of air in incineration would result in increase of combustion efficiency and capacity, and reduction of off-gas product. Especially, the off-gas could be reduced below a quarter, which might reduce off-gas treatment facilities, and also increase an efficiency of off-gas treatment. However, the use of oxygen might also lead to local overheating and high nitrogen oxides (NOx) formation. To overcome these problems, an application of low NOx oxy-fuel burner and recycling of a part of off-gas to combustion chamber have been suggested.

  14. Implementing oxygen control in chip-based cell and tissue culture systems.

    Science.gov (United States)

    Oomen, Pieter E; Skolimowski, Maciej D; Verpoorte, Elisabeth

    2016-09-21

    Oxygen is essential in the energy metabolism of cells, as well as being an important regulatory parameter influencing cell differentiation and function. Interest in precise oxygen control for in vitro cultures of tissues and cells continues to grow, especially with the emergence of the organ-on-a-chip and the desire to emulate in vivo conditions. This was recently discussed in this journal in a Critical Review by Brennan et al. (Lab Chip (2014). DOI: ). Microfluidics can be used to introduce flow to facilitate nutrient supply to and waste removal from in vitro culture systems. Well-defined oxygen gradients can also be established. However, cells can quickly alter the oxygen balance in their vicinity. In this Tutorial Review, we expand on the Brennan paper to focus on the implementation of oxygen analysis in these systems to achieve continuous monitoring. Both electrochemical and optical approaches for the integration of oxygen monitoring in microfluidic tissue and cell culture systems will be discussed. Differences in oxygen requirements from one organ to the next are a challenging problem, as oxygen delivery is limited by its uptake into medium. Hence, we discuss the factors determining oxygen concentrations in solutions and consider the possible use of artificial oxygen carriers to increase dissolved oxygen concentrations. The selection of device material for applications requiring precise oxygen control is discussed in detail, focusing on oxygen permeability. Lastly, a variety of devices is presented, showing the diversity of approaches that can be employed to control and monitor oxygen concentrations in in vitro experiments.

  15. DNA Uptake by Transformable Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Lacks, Sanford A.

    1999-03-31

    The various processes of DNA uptake by cells can be categorized as: viral DNA entry, conjugation, or transformation. Within each category, a variety of mechanisms have been found. However, considerable similarities occur among the different mechanisms of conjugation and, especially, transformation. All of these natural mechanisms of DNA transfer are quite elaborate and involve multiple protein components, as the case may be, of the virus, the donor cell, and the recipient cell. The mechanisms of viral infection and conjugation will be discussed mainly with respect to their relevance to transformation.

  16. DNA UPTAKE BY TRANSFORMABLE BACTERIA

    Energy Technology Data Exchange (ETDEWEB)

    LACKS,S.A.

    1999-09-07

    The various processes of DNA uptake by cells can be categorized as: viral DNA entry, conjugation, or transformation. Within each category, a variety of mechanisms have been found. However, considerable similarities occur among the different mechanisms of conjugation and, especially, transformation. All of these natural mechanisms of DNA transfer are quite elaborate and involve multiple protein components, as the case may be, of the virus, the donor cell, and the recipient cell. The mechanisms of viral infection and conjugation will be discussed mainly with respect to their relevance to transformation.

  17. 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

  18. High-intensity interval training and β-hydroxy-β-methylbutyric free acid improves aerobic power and metabolic thresholds

    OpenAIRE

    Robinson, Edward H; Stout, Jeffrey R; Miramonti, Amelia A; Fukuda, David H; Wang, Ran; Townsend, Jeremy R; Mangine, Gerald T; Fragala, Maren S; Hoffman, Jay R

    2014-01-01

    Background Previous research combining Calcium β-hydroxy-β-methylbutyrate (CaHMB) and running high-intensity interval training (HIIT) have shown positive effects on aerobic performance measures. The purpose of this study was to examine the effect of β-hydroxy-β-methylbutyric free acid (HMBFA) and cycle ergometry HIIT on maximal oxygen consumption (VO2peak), ventilatory threshold (VT), respiratory compensation point (RCP) and time to exhaustion (Tmax) in college-aged men and women. Methods Thi...

  19. Ocean uptake of carbon dioxide

    International Nuclear Information System (INIS)

    Peng, Tsung-Hung; Takahashi, Taro

    1993-01-01

    Factors controlling the capacity of the ocean for taking up anthropogenic C0 2 include carbon chemistry, distribution of alkalinity, pCO 2 and total concentration of dissolved C0 2 , sea-air pCO 2 difference, gas exchange rate across the sea-air interface, biological carbon pump, ocean water circulation and mixing, and dissolution of carbonate in deep sea sediments. A general review of these processes is given and models of ocean-atmosphere system based on our understanding of these regulating processes axe used to estimate the magnitude of C0 2 uptake by the ocean. We conclude that the ocean can absorb up to 35% of the fossil fuel emission. Direct measurements show that 55% Of C0 2 from fossil fuel burning remains in the atmosphere. The remaining 10% is not accounted for by atmospheric increases and ocean uptake. In addition, it is estimated that an amount equivalent to 30% of recent annual fossil fuel emissions is released into the atmosphere as a result of deforestation and farming. To balance global carbon budget, a sizable carbon sink besides the ocean is needed. Storage of carbon in terrestrial biosphere as a result of C0 2 fertilization is a potential candidate for such missing carbon sinks

  20. High Selectivity Oxygen Delignification

    Energy Technology Data Exchange (ETDEWEB)

    Lucian A. Lucia

    2005-11-15

    Project Objective: The objectives of this project are as follows: (1) Examine the physical and chemical characteristics of a partner mill pre- and post-oxygen delignified pulp and compare them to lab generated oxygen delignified pulps; (2) Apply the chemical selectivity enhancement system to the partner pre-oxygen delignified pulps under mill conditions (with and without any predetermined amounts of carryover) to determine how efficiently viscosity is preserved, how well selectivity is enhanced, if strength is improved, measure any yield differences and/or bleachability differences; and (3) Initiate a mill scale oxygen delignification run using the selectivity enhancement agent, collect the mill data, analyze it, and propose any future plans for implementation.

  1. 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...

  2. Pathology of oxygen

    National Research Council Canada - National Science Library

    Autor, Anne Pomeroy

    1982-01-01

    This volume has been designed to provide those interested in oxygen toxicity with a working knowledge of advancement in the field with the intention that the topics described in each chapter will be immediately useful...

  3. Using oxygen at home

    Science.gov (United States)

    ... at Home Tell your local fire department, electric company, and telephone company that you use oxygen in your home. They ... M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health ...

  4. Pathology of oxygen

    National Research Council Canada - National Science Library

    Autor, Anne Pomeroy

    1982-01-01

    .... The book is divided into three general sections. The first and smallest section of the book explains the molecular and biochemical basis of our current understanding of oxygen radical toxicity as well as the means by which normal aerobic cells...

  5. Optic nerve oxygen tension

    DEFF Research Database (Denmark)

    la Cour, M; Kiilgaard, Jens Folke; Eysteinsson, T

    2000-01-01

    To investigate the influence of acute changes in intraocular pressure on the oxygen tension in the vicinity of the optic nerve head under control conditions and after intravenous administration of 500 mg of the carbonic anhydrase inhibitor dorzolamide.......To investigate the influence of acute changes in intraocular pressure on the oxygen tension in the vicinity of the optic nerve head under control conditions and after intravenous administration of 500 mg of the carbonic anhydrase inhibitor dorzolamide....

  6. Ekstrakorporal oxygenering ved legionellapneumoni

    DEFF Research Database (Denmark)

    Uslu, Bülent; Steensen, Morten

    2009-01-01

    We present a case report with a 49-year-old woman with legionella pneumonia and fulminant respiratory failure. Despite maximal conventional respirator treatment with positive pressure ventilation, 100% oxygen and pharmacological treatment in an intensive care unit, further deterioration with hypo......We present a case report with a 49-year-old woman with legionella pneumonia and fulminant respiratory failure. Despite maximal conventional respirator treatment with positive pressure ventilation, 100% oxygen and pharmacological treatment in an intensive care unit, further deterioration...

  7. 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.

  8. Singlet oxygen quenching by oxygen in tetraphenyl-porphyrin solutions

    International Nuclear Information System (INIS)

    Dedic, Roman; Korinek, Miloslav; Molnar, Alexander; Svoboda, Antonin; Hala, Jan

    2006-01-01

    Time-resolved measurement of singlet oxygen infrared phosphorescence is a powerful tool for determination of quantum yields and kinetics of its photosensitization. This technique was employed to investigate in detail the previously observed effect of singlet oxygen quenching by oxygen. The question whether the singlet oxygen is quenched by oxygen in ground or in excited state was addressed by study of two complementary dependencies of singlet oxygen lifetimes: on dissolved oxygen concentration and on excitation intensity. Oxygen concentration dependence study of meso-tetra(4-sulphonato)phenylporphyrin (TPPS 4 ) phosphorescence kinetics showed linearity of the dependence of TPPS 4 triplet state rate-constant. Corresponding bimolecular quenching constant of (1.5±0.1)x10 9 l/mol s was obtained. On the other hand, rate constants of singlet oxygen depopulation exhibit nonlinear dependence on oxygen concentration. Comparison of zero oxygen concentration-extrapolated value of singlet oxygen lifetime of (6.5±0.4) μs to (3.7±0.1) μs observed under air-saturated conditions indicates importance of the effect of quenching of singlet oxygen by oxygen. Upward-sloping dependencies of singlet oxygen depopulation rate-constant on excitation intensity evidence that singlet oxygen is predominantly quenched by oxygen in excited singlet state

  9. Increased muscle glucose uptake during contractions

    DEFF Research Database (Denmark)

    Ploug, Thorkil; Galbo, Henrik; Richter, Erik

    1984-01-01

    We reinvestigated the prevailing concept that muscle contractions only elicit increased muscle glucose uptake in the presence of a so-called "permissive" concentration of insulin (Berger et al., Biochem. J. 146: 231-238, 1975; Vranic and Berger, Diabetes 28: 147-163, 1979). Hindquarters from rats...... in severe ketoacidosis were perfused with a perfusate containing insulin antiserum. After 60 min perfusion, electrical stimulation increased glucose uptake of the contracting muscles fivefold. Also, subsequent contractions increased glucose uptake in hindquarters from nondiabetic rats perfused for 1.5 h......-methylglucose uptake increased during contractions and glucose uptake was negative at rest and zero during contractions. An increase in muscle transport and uptake of glucose during contractions does not require the presence of insulin. Furthermore, glucose transport in contracting muscle may only increase if glycogen...

  10. Cell uptake survey of pegylated nanographene oxide.

    Science.gov (United States)

    Vila, M; Portolés, M T; Marques, P A A P; Feito, M J; Matesanz, M C; Ramírez-Santillán, C; Gonçalves, G; Cruz, S M A; Nieto, A; Vallet-Regi, M

    2012-11-23

    Graphene and more specifically, nanographene oxide (GO) has been proposed as a highly efficient antitumoral therapy agent. Nevertheless, its cell uptake kinetics, its influence in different types of cells and the possibility of controlling cellular internalization timing, is still a field that remains unexplored. Herein, different cell types have been cultured in vitro for several incubation periods in the presence of 0.075 mg ml(-1) pegylated GO solutions. GO uptake kinetics revealed differences in the agent's uptake amount and speed as a function of the type of cell involved. Osteoblast-like cells GO uptake is higher and faster without resulting in greater cell membrane damage. Moreover, the dependence on the commonly used PEG nature (number of branches) also influences the viability and cell uptake speed. These facts play an important role in the future definition of timing parameters and selective cell uptake control in order to achieve an effective therapy.

  11. Cell uptake survey of pegylated nanographene oxide

    International Nuclear Information System (INIS)

    Vila, M; Nieto, A; Vallet-Regi, M; Portolés, M T; Feito, M J; Matesanz, M C; Ramírez-Santillán, C; Marques, P A A P; Gonçalves, G; Cruz, S M A

    2012-01-01

    Graphene and more specifically, nanographene oxide (GO) has been proposed as a highly efficient antitumoral therapy agent. Nevertheless, its cell uptake kinetics, its influence in different types of cells and the possibility of controlling cellular internalization timing, is still a field that remains unexplored. Herein, different cell types have been cultured in vitro for several incubation periods in the presence of 0.075 mg ml −1 pegylated GO solutions. GO uptake kinetics revealed differences in the agent’s uptake amount and speed as a function of the type of cell involved. Osteoblast-like cells GO uptake is higher and faster without resulting in greater cell membrane damage. Moreover, the dependence on the commonly used PEG nature (number of branches) also influences the viability and cell uptake speed. These facts play an important role in the future definition of timing parameters and selective cell uptake control in order to achieve an effective therapy. (paper)

  12. Gastric gallium-67 uptake in gastritis

    International Nuclear Information System (INIS)

    Yeh, E.L.; Tisdale, P.L.; Zielonka, J.S.

    1983-01-01

    Even though Ga-67 imaging has been used widely in the diagnosis of malignant as well as inflammatory lesions, its uptake in the stomach has been reported in the literature mainly in gastric lymphoma and carcinoma. As shown in this case, intense gastric uptake of the radionuclide may be seen in common gastritis without malignancy. Perhaps the benign gastric uptake of Ga-67 deserves more emphasis

  13. Changes in calcium uptake rate by rat cardiac mitochondria during postnatal development.

    Science.gov (United States)

    Bassani, R A; Fagian, M M; Bassani, J W; Vercesi, A E

    1998-10-01

    Ca2+ uptake, transmembrane electrical potential (Deltapsim) and oxygen consumption were measured in isolated ventricular mitochondria of rats from 3 days to 5 months of age. Estimated values of ruthenium red-sensitive, succinate-supported maximal rate of Ca2+ uptake (Vmax, expressed as nmol Ca2+/min/mg protein) were higher in neonates and gradually fell during postnatal development (from 435+/-24 at 3-6 days, to 156+/-10 in adults,Palpha-ketoglutarate as substrates) and state 3ADP (alpha-ketoglutarate-supported) respiration rates, as well as Deltapsim values (approximately-150 mV). Respiration-independent Deltapsim and Ca2+ uptake, supported by valinomycin-induced K+ efflux were also investigated at these ages. A transient Deltapsim (approximately -30 mV) was evoked by valinomycin in both neonatal and adult mitochondria. Respiration-independent Ca2+ uptake was also transient, but its initial rate was significantly higher in neonates than in adults (49. 4+/-10.0v 28.0+/-5.7 mmol Ca2+/min/mg protein,P<0.01). These results indicate that Ca2+ uptake capacity of rat cardiac mitochondria is remarkably high just after birth and declines over the first weeks of postnatal life, without change in apparent affinity of the transporter. Increased mitochondrial Ca2+ uptake rate in neonates appears to be related to the uniporter itself, rather than to modification of the driving force of the transport. Copyright 1998 Academic Press

  14. Radioiodine uptake by plants from soils

    International Nuclear Information System (INIS)

    Sabova, T.

    1976-01-01

    The uptake and accumulation of radioiodine by wheat, maize and peas from various types of soil have been studied. The uptake depends on the type of soil, on its content of organic matter and on the amount of fertilizer. Radioiodine is mainly accumulated in the roots. Accumulation in above-ground plant parts decreases in the following order: wheat, maize, peas. Uptake was highest from humus and clay soils and lowest from black and meadow soils. Application of chloride fertilizer or carrier iodine lead to an increase of radioiodine uptake in the whole plant. (author)

  15. Physiological FDG uptake in the palatine tonsils

    International Nuclear Information System (INIS)

    Kawabe, Joji; Okamura, Terue; Shakudo, Miyuki

    2001-01-01

    In clinical F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) studies of the head and neck region, remarkable symmetric tonsillar FDG uptake is sometimes observed. We determined the incidence and degree of tonsillar FDG uptake and investigated the significance of tonsillar FDG uptake. Between June 1998 and August 1998, we obtained informed consent from 17 patients who were scheduled to undergo a FDG-PET study for their own disease (11 men and 6 women; aged 22 to 77 yr) and who did not have head and neck disease to perform FDG-PET scanning of the head and neck region in addition to their target organs. The incidence and degree of tonsillar FDG uptake were determined. Remarkable tonsillar FDG uptake was found in 9 patients. The SUVs of these FDG uptakes ranged from 2.48 to 6.75, with a mean of 4.29±1.20 (SD). Tonsillar FDG uptakes in the remaining 8 patients were not remarkable, and their SUVs ranged from 1.93 to 3.31, with a mean of 2.46±0.45. Head and neck disease does not appear to have been responsible for the increase in tonsillar FDG uptake. Differences among tonsillar FDG uptake in these 17 patients without head and neck disease appear to reflect differences in activity of ''physiological'' inflammation of the palatine tonsils. (author)

  16. Radioiodine uptake in inactive pulmonary tuberculosis

    International Nuclear Information System (INIS)

    Bakheet, S.M.; Powe, J.; Al Suhaibani, H.; Hammami, M.M.; Bazarbashi, M.

    1999-01-01

    Radioiodine may accumulate at sites of inflammation or infection. We have seen such accumulation in six thyroid cancer patients with a history of previously treated pulmonary tuberculosis. We also review the causes of false-positive radioiodine uptake in lung infection/inflammation. Eight foci of radioiodine uptake were seen on six iodine-123 diagnostic scans. In three foci, the uptake was focal and indistinguishable from thyroid cancer pulmonary metastases from thyroid cancer. In the remaining foci, the uptake appeared nonsegmental, linear or lobar, suggesting a false-positive finding. The uptake was unchanged, variable in appearance or non-persistent on follow-up scans and less extensive than the fibrocystic changes seen on chest radiographs. In the two patients studied, thyroid hormone level did not affect the radioiodine lung uptake and there was congruent gallium-67 uptake. None of the patients had any evidence of thyroid cancer recurrence or of reactivation of tuberculosis and only two patients had chronic intermittent chest symptoms. Severe bronchiectasis, active tuberculosis, acute bronchitis, respiratory bronchiolitis, rheumatoid arthritis-associated lung disease and fungal infection such as Allescheria boydii and aspergillosis can lead to different patterns of radioiodine chest uptake mimicking pulmonary metastases. Pulmonary scarring secondary to tuberculosis may predispose to localized radioiodine accumulation even in the absence of clinically evident active infection. False-positive radioiodine uptake due to pulmonary infection/inflammation should be considered in thyroid cancer patients prior to the diagnosis of pulmonary metastases. (orig.)

  17. Aerobic capacity of Peruvian Quechua: a test of the developmental adaptation hypothesis.

    Science.gov (United States)

    Kiyamu, Melisa; Rivera-Chira, María; Brutsaert, Tom D

    2015-03-01

    High altitude natives are reported to have outstanding work capacity in spite of the challenge of oxygen transport and delivery in hypoxia. To evaluate the developmental effect of lifelong exposure to hypoxia on aerobic capacity, VO2peak was measured on two groups of Peruvian Quechua subjects (18-35 years), who differed in their developmental exposure to altitude. Male and female volunteers were recruited in Lima, Peru (150 m), and were divided in two groups, based on their developmental exposure to hypoxia, those: a) Born at sea-level individuals (BSL), with no developmental exposure to hypoxia (n = 34) and b) Born at high-altitude individuals (BHA) with full developmental exposure to hypoxia (n = 32), but who migrated to sea-level as adults (>16-years-old). Tests were conducted both in normoxia (BP = 750 mm Hg) and normobaric hypoxia at sea-level (BP = 750 mm Hg, FiO2  = 0.12, equivalent to 4,449 m), after a 2-month training period (in order to control for initial differences in physical fitness) at sea-level. BHA had a significantly higher VO2peak at hypoxia (40.31 ± 1.0 ml/min/kg) as compared to BSL (35.78 ± 0.96 ml/min/kg, P = 0.001), adjusting for sex. The decrease of VO2peak at HA relative to SL (ΔVO2peak ) was not different between groups, controlling for baseline levels (VO2peak at sea-level) and sex (BHA = 0.35 ± 0.04 l/min, BSL = 0.44 ± 0.04 l/min; P = 0.12). Forced vital capacity (controlling for height) and the residuals of VO2peak (controlling for weight) had a significant association in the BHA group only (r = 0.155; P = 0.031). In sum, results indicate that developmental exposure to altitude constitutes an important factor to determine superior exercise performance. © 2014 Wiley Periodicals, Inc.

  18. Reactive oxygen species-driven HIF1α triggers accelerated glycolysis in endothelial cells exposed to low oxygen tension

    International Nuclear Information System (INIS)

    Paik, Jin-Young; Jung, Kyung-Ho; Lee, Jin-Hee; Park, Jin-Won; Lee, Kyung-Han

    2017-01-01

    Endothelial cells and their metabolic state regulate glucose transport into underlying tissues. Here, we show that low oxygen tension stimulates human umbilical vein endothelial cell 18 F–fluorodeoxyglucose ( 18 F–FDG) uptake and lactate production. This was accompanied by augmented hexokinase activity and membrane Glut-1, and increased accumulation of hypoxia-inducible factor-1α (HIF1α). Restoration of oxygen reversed the metabolic effect, but this was blocked by HIF1α stabilization. Hypoxia-stimulated 18 F–FDG uptake was completely abrogated by silencing of HIF1α expression or by a specific inhibitor. There was a rapid and marked increase of reactive oxygen species (ROS) by hypoxia, and ROS scavenging or NADPH oxidase inhibition completely abolished hypoxia-stimulated HIF1α and 18 F–FDG accumulation, placing ROS production upstream of HIF1α signaling. Hypoxia-stimulated HIF1α and 18 F–FDG accumulation was blocked by the protein kinase C (PKC) inhibitor, staurosporine. The phosphatidylinositol 3-kinase (PI3K) inhibitor, wortmannin, blocked hypoxia-stimulated 18 F–FDG uptake and attenuated hypoxia-responsive element binding of HIF1α without influencing its accumulation. Thus, ROS-driven HIF1α accumulation, along with PKC and PI3K signaling, play a key role in triggering accelerated glycolysis in endothelial cells under hypoxia, thereby contributing to 18 F–FDG transport.

  19. OXYGEN DEPLETION IN THE INTERSTELLAR MEDIUM: IMPLICATIONS FOR GRAIN MODELS AND THE DISTRIBUTION OF ELEMENTAL OXYGEN

    International Nuclear Information System (INIS)

    Whittet, D. C. B.

    2010-01-01

    This paper assesses the implications of a recent discovery that atomic oxygen is being depleted from diffuse interstellar gas at a rate that cannot be accounted for by its presence in silicate and metallic oxide particles. To place this discovery in context, the uptake of elemental O into dust is considered over a wide range of environments, from the tenuous intercloud gas and diffuse clouds sampled by the depletion observations to dense clouds where ice mantles and gaseous CO become important reservoirs of O. The distribution of O in these contrasting regions is quantified in terms of a common parameter, the mean number density of hydrogen (n H ). At the interface between diffuse and dense phases (just before the onset of ice-mantle growth) as much as ∼160 ppm of the O abundance is unaccounted for. If this reservoir of depleted oxygen persists to higher densities it has implications for the oxygen budget in molecular clouds, where a shortfall of the same order is observed. Of various potential carriers, the most plausible appears to be a form of O-bearing carbonaceous matter similar to the organics found in cometary particles returned by the Stardust mission. The 'organic refractory' model for interstellar dust is re-examined in the light of these findings, and it is concluded that further observations and laboratory work are needed to determine whether this class of material is present in quantities sufficient to account for a significant fraction of the unidentified depleted oxygen.

  20. Chromium isotope uptake in carbonates

    DEFF Research Database (Denmark)

    Rodler, Alexandra

    related to the rise of oxygen and the evolution of the biosphere. However, before the Cr isotopesystem can be applied to faithfully delineate paleo-environmental changes, careful assessment of the signal robustness and a thorough understanding of the Cr cycle in Earth system processes is necessary...... composition of contemporaneous seawater. Marine carbonates are ubiquitous throughout Earth’s rock record rendering them a particularly interesting archive for constraining past changes in ocean chemistry. This thesis includes an investigation of the fractionation behavior of Cr isotopesduring coprecipitation...

  1. 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.

  2. Closed Loop Control of Oxygen Delivery and Oxygen Generation

    Science.gov (United States)

    2017-08-01

    were used for this study and were connected via a USB cable to allow communication. The ventilator was modified to allow closed loop control of oxygen...connected via a USB cable to allow communication. The ventilator was modified to allow closed loop control of oxygen based on the oxygen saturation...2017-4119, 28 Aug 2017. oximetry (SpO2) and intermittent arterial blood sampling for arterial oxygen tension (partial pressure of oxygen [PaO2]) and

  3. Characterization of Activity and Cardiovascular Responses During Surfing in Recreational Male Surfers Between the Ages of 18 and 75 Years Old.

    Science.gov (United States)

    LaLanne, Christine L; Cannady, Michael S; Moon, Joseph F; Taylor, Danica L; Nessler, Jeff A; Crocker, George H; Newcomer, Sean C

    2017-04-01

    Participation in surfing has evolved to include all age groups. Therefore, the purpose of this study was to determine whether activity levels and cardiovascular responses to surfing change with age. Surfing time and heart rate (HR) were measured for the total surfing session and within each activity of surfing (paddling, sitting, wave riding, and miscellaneous). Peak oxygen consumption (VO 2peak ) was also measured during laboratory-based simulated surfboard paddling on a modified swim bench ergometer. VO 2peak decreased with age during simulated paddling (r = -.455, p surfing (p = .837) and time spent within each activity of surfing did not differ with age (n = 160). Mean HR during surfing significantly decreased with age (r = -.231, p = .004). However, surfing HR expressed as a percent of age-predicted maximum increased significantly with age. Therefore, recreational surfers across the age spectrum are achieving intensities and durations that are consistent with guidelines for cardiovascular health.

  4. Normal cerebral FDG uptake during childhood

    International Nuclear Information System (INIS)

    London, Kevin; Howman-Giles, Robert

    2014-01-01

    Current understanding of cerebral FDG uptake during childhood originates from a small number of studies in patients with neurological abnormalities. Our aim was to describe cerebral FDG uptake in a dataset of FDG PET scans in children more likely to represent a normal population. We reviewed cerebral FDG PET scans in children up to 16 years of age with suspected/proven extracranial malignancies and the following exclusions: central nervous system metastases, previous malignancies, previous chemotherapy or radiotherapy, development of cerebral metastases during therapy, neurological conditions, taking antiepileptic medication or medications likely to interfere with cerebral metabolism, and general anaesthesia within 24 h. White matter, basal ganglia, thalamus and the cerebellar cortex were analysed using regional SUV max , and the cerebral cortex, basal ganglia, thalamus and cerebellum were analysed using a regional relative uptake analysis in comparison to maximal cortical uptake. Scans from 30 patients (age range 11 months to 16 years, mean age 10 years 5 months) were included. All regions showed increasing SUV max with age. The parietal, occipital, lateral temporal and medial temporal lobes showed lower rates of increasing FDG uptake causing changing patterns of regional FDG uptake during childhood. The cortical regions showing the most intense uptake in early childhood were the parietal and occipital lobes. At approximately 7 years of age these regions had relatively less uptake than the frontal lobes and at approximately 10 years of age these regions had relatively less uptake than the thalamus. Relative FDG uptake in the brain has not reached an adult pattern by 1 year of age, but continues to change up to 16 years of age. The changing pattern is due to different regional rates of increasing cortical FDG uptake, which is less rapid in the parietal, occipital and temporal lobes than in the frontal lobes. (orig.)

  5. Normal cerebral FDG uptake during childhood

    Energy Technology Data Exchange (ETDEWEB)

    London, Kevin [The Children' s Hospital at Westmead, Department of Nuclear Medicine, Sydney, NSW (Australia); University of Sydney, Discipline of Paediatrics and Child Health, Sydney Medical School, Sydney, NSW (Australia); Howman-Giles, Robert [The Children' s Hospital at Westmead, Department of Nuclear Medicine, Sydney, NSW (Australia); University of Sydney, Disciplines of Imaging and Paediatrics and Child Health, Sydney Medical School, Sydney, NSW (Australia)

    2014-04-15

    Current understanding of cerebral FDG uptake during childhood originates from a small number of studies in patients with neurological abnormalities. Our aim was to describe cerebral FDG uptake in a dataset of FDG PET scans in children more likely to represent a normal population. We reviewed cerebral FDG PET scans in children up to 16 years of age with suspected/proven extracranial malignancies and the following exclusions: central nervous system metastases, previous malignancies, previous chemotherapy or radiotherapy, development of cerebral metastases during therapy, neurological conditions, taking antiepileptic medication or medications likely to interfere with cerebral metabolism, and general anaesthesia within 24 h. White matter, basal ganglia, thalamus and the cerebellar cortex were analysed using regional SUV{sub max}, and the cerebral cortex, basal ganglia, thalamus and cerebellum were analysed using a regional relative uptake analysis in comparison to maximal cortical uptake. Scans from 30 patients (age range 11 months to 16 years, mean age 10 years 5 months) were included. All regions showed increasing SUV{sub max} with age. The parietal, occipital, lateral temporal and medial temporal lobes showed lower rates of increasing FDG uptake causing changing patterns of regional FDG uptake during childhood. The cortical regions showing the most intense uptake in early childhood were the parietal and occipital lobes. At approximately 7 years of age these regions had relatively less uptake than the frontal lobes and at approximately 10 years of age these regions had relatively less uptake than the thalamus. Relative FDG uptake in the brain has not reached an adult pattern by 1 year of age, but continues to change up to 16 years of age. The changing pattern is due to different regional rates of increasing cortical FDG uptake, which is less rapid in the parietal, occipital and temporal lobes than in the frontal lobes. (orig.)

  6. Oxygen Dependent Biocatalytic Processes

    DEFF Research Database (Denmark)

    Pedersen, Asbjørn Toftgaard

    Enzyme catalysts have the potential to improve both the process economics and the environ-mental profile of many oxidation reactions especially in the fine- and specialty-chemical industry, due to their exquisite ability to perform stereo-, regio- and chemo-selective oxida-tions at ambient...... to aldehydes and ketones, oxyfunctionalization of C-H bonds, and epoxidation of C-C double bonds. Although oxygen dependent biocatalysis offers many possibilities, there are numerous chal-lenges to be overcome before an enzyme can be implemented in an industrial process. These challenges requires the combined...... far below their potential maximum catalytic rate at industrially relevant oxygen concentrations. Detailed knowledge of the en-zyme kinetics are therefore required in order to determine the best operating conditions and design oxygen supply to minimize processing costs. This is enabled...

  7. Oxygen therapy reduces postoperative tachycardia

    DEFF Research Database (Denmark)

    Stausholm, K; Kehlet, H; Rosenberg, J

    1995-01-01

    Concomitant hypoxaemia and tachycardia in the postoperative period is unfavourable for the myocardium. Since hypoxaemia per se may be involved in the pathogenesis of postoperative tachycardia, we have studied the effect of oxygen therapy on tachycardia in 12 patients randomly allocated to blinded...... air or oxygen by facemask on the second or third day after major surgery. Inclusion criteria were arterial hypoxaemia (oxygen saturation 90 beat.min-1). Each patient responded similarly to oxygen therapy: an increase in arterial oxygen saturation and a decrease...... in heart rate (p oxygen has a positive effect on the cardiac oxygen delivery and demand balance....

  8. Hyperbaric oxygen and radiotherapy

    International Nuclear Information System (INIS)

    Mayer, R.; Hamilton-Farrell, M.R.; Kleij, A.J. van der

    2005-01-01

    Background: Hyperbaric oxygen (HBO) therapy is the inhalation of 100% oxygen at a pressure of at least 1.5 atmospheres absolute (150 kPa). It uses oxygen as a drug by dissolving it in the plasma and delivering it to the tissues independent of hemoglobin. For a variety of organ systems, HBO is known to promote new vessel growth into areas with reduced oxygen tension due to poor vascularity, and therewith promotes wound healing and recovery of radiation-injured tissue. Furthermore, tumors may be sensitized to irradiation by raising intratumoral oxygen tensions. Methods: A network of hyperbaric facilities exists in Europe, and a number of clinical studies are ongoing. The intergovernmental framework COST B14 action 'Hyperbaric Oxygen Therapy' started in 1999. The main goal of the Working Group Oncology is preparation and actual implementation of prospective study protocols in the field of HBO and radiation oncology in Europe. Results: In this paper a short overview on HBO is given and the following randomized clinical studies are presented: (a) reirradiation of recurrent squamous cell carcinoma of the head and neck after HBO sensitization; (b) role of HBO in enhancing radiosensitivity on glioblastoma multiforme; (c) osseointegration in irradiated patients; adjunctive HBO to prevent implant failures; (d) the role of HBO in the treatment of late irradiation sequelae in the pelvic region. The two radiosensitization protocols (a, b) allow a time interval between HBO and subsequent irradiation of 10-20 min. Conclusion: Recruitment of centers and patients is being strongly encouraged, detailed information is given on www.oxynet.org. (orig.)

  9. Novel nanostructured oxygen sensor

    Science.gov (United States)

    Boardman, Alan James

    New government regulations and industry requirements for medical oxygen sensors require the development of alternate materials and process optimization of primary sensor components. Current oxygen sensors are not compliant with the Restriction of Hazardous Substances (RoHS) Directive. This work focused on two areas. First, was finding suitable readily available materials for the sensor anodes. Second was optimizing the processing of the sensor cathode membrane for reduced delamination. Oxygen sensors were made using tin (Sn) and bismuth (Bi) electrodes, potassium hydroxide (KOH) and acetic acid (CH3COOH) electrolytes with platinum (Pt) and gold (Au) reference electrodes. Bi electrodes were fabricated by casting and pressing processes. Electrochemical characterization of the Sn and Bi electrodes was performed by Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and sensing characterization per BSEN ISO 21647:2009 at various oxygen percentages, 0%, 20.9% and 100% oxygen levels with an automated test apparatus. The Sn anode with both electrolyte solutions showed good oxygen sensing properties and performance in a sensor. This system shows promise for replacement of Pb electrodes as required by the RoHS Directive. The Bi anode with Au cathode in both KOH and CH3COOH electrolytes showed acceptable performance and oxygen sensing properties. The Bi anodes fabricated by separate manufacturing methods demonstrated effectiveness for use in medical oxygen sensors. Gold thin films were prepared by magnetron sputtering on Flouroethylene Polymer (FEP) films. The FEP substrate temperature ranged from -77°C to 50°C. X-Ray Diffraction (XRD) and 4-point resistivity characterized the effects of substrate temperature to Au thin film particle size. XRD peak broadening and resistivity measurements showed a strong correlation of particle size to FEP substrate temperature. Particle size at 50°C was 594A and the -77°C particle size was 2.4 x 103A. Substrate

  10. Uptake of organic nitrogen by plants

    Science.gov (United States)

    Torgny Nasholm; Knut Kielland; Ulrika. Ganeteg

    2009-01-01

    Languishing for many years in the shadow of plant inorganic nitrogen (N) nutrition research, studies of organic N uptake have attracted increased attention during the last decade. The capacity of plants to acquire organic N, demonstrated in laboratory and field settings, has thereby been well established. Even so, the ecological significance of organic N uptake for...

  11. Gallium 67 uptake in thymic rebound

    International Nuclear Information System (INIS)

    Hurst, R.; Sabio, H.; Teates, C.D.

    1988-01-01

    We have reported a case of localized thymic enlargement and uptake of gallium 67 in a child who had received antineoplastic chemotherapy. The enlarged thymus showed normal histology, a picture consistent with thymic rebound after nonspecific stress. This case further demonstrates the need to consider thymic rebound as a cause of gallium 67 uptake in children with neoplastic diseases

  12. Uptake of inorganic contaminants by pteridophytes

    International Nuclear Information System (INIS)

    Zheng Jiemin; Chen Ziyuan; Tang Shirong; Guangzhou Univ., Guangzhou; Ding Bingyang

    2005-01-01

    The review covers results at home and abroad in terms of uptake of inorganic contaminants by pteridophytes, and suggests pteridophytes' significance in phytoremediation; the mechanisms related to uptake of inorganic contaminants by pteridophytes and some methods and means used for research on the mechanism are also introduced; the authors' viewpoints on future development trends are presented in this paper. (authors)

  13. Nitrogen uptake kinetics of freshly isolated zooxanthellae

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar, M.V.M.; Wafar, S.; Rajkumar, R.

    that for nitrate [2.8 nmol. ( mu chl-a)./1h/1] and urea [0.37 nmol. ( mu chl-a)./1h/1]. Half-saturation constants for uptake of the three nitrogen compounds were in the range of 10-15 mu mol.l/1. Generally, uptake of any one nitrogen substrate appears to be inhibit...

  14. Radio-active iodine uptake in vitiligo

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, V.; Shankar, V.; Chaudhary, S.; Bhatia, K.K.; Mehta, L.K.; Arora, D.R. (Medical College and Hospital, Rohtak-124001 (India))

    1990-01-01

    Vitiligo and thyroid disease are commonly associated disorders. Twenty-two clinically euthyroid vitiligo patients were studied for functional assessment of thyroid by radioactive iodine uptake assay. Half of them showed abnormal uptake values at 24 hours. Of these patients, 90% had lower values indicating a tendency towards developing hypothyroid state. Subclinical thyroid dysfunction in vitiligo appears to be an adaptive change. (author).

  15. Radio-active iodine uptake in vitiligo

    International Nuclear Information System (INIS)

    Kumar, V.; Shankar, V.; Chaudhary, S.; Bhatia, K.K.; Mehta, L.K.; Arora, D.R.

    1990-01-01

    Vitiligo and thyroid disease are commonly associated disorders. Twenty-two clinically euthyroid vitiligo patients were studied for functional assessment of thyroid by radioactive iodine uptake assay. Half of them showed abnormal uptake values at 24 hours. Of these patients, 90% had lower values indicating a tendency towards developing hypothyroid state. Subclinical thyroid dysfunction in vitiligo appears to be an adaptive change. (author)

  16. OXYGEN MANAGEMENT DURING ALCOHOLIC FERMENTATION

    OpenAIRE

    MOENNE VARGAS, MARÍA ISABE

    2013-01-01

    Oxygen additions are a common practice in winemaking, as oxygen has a positive effect in fermentative kinetics, biomass synthesis and improvement of color, structure and :flavor in treated wines. However, most oxygen additions are carried out heuristically through pump-over operations solely on a know-how basis, which is difficult to manage in terms of the exact quantity of oxygen transferred to the fermenting must. It is important to estímate the amount of oxygen added because...

  17. Uptake and transport of chromium in plants

    International Nuclear Information System (INIS)

    Ramachandran, V.; D'souza, T.J.; Mistry, K.B.

    1980-01-01

    The uptake of chromium, an important soil and water pollutant, by five different plant species was examined in nutrient culture experiments using chromium-51 as a tracer. The concentration in aerial tissues of both trivalent and hexavalent forms of chromium was the greatest in peas followed by beans, tomato and the cereals over identical uptake periods. The uptake of 51 Cr 3+ was, in general, greater than 51 CrO 4 2- . Studies with bean plants indicated that shoot uptake of both forms of chromium decreased with increasing pH and salt concentration of the external solution. Concentrations of 10 -4 M and 10 -5 M DNP inhibited 51 Cr uptake by bean shoots. (author)

  18. Impaired Economy of Gait and Decreased Six-Minute Walk Distance in Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    Leslie I. Katzel

    2012-01-01

    Full Text Available Changes in the biomechanics of gait may alter the energy requirements of walking in Parkinson's Disease (PD. This study investigated economy of gait during submaximal treadmill walking in 79 subjects with mild to moderate PD and the relationship between gait economy and 6-minute walk distance (6 MW. Oxygen consumption (VO2 at the self-selected treadmill walking speed averaged 64% of peak oxygen consumption (VO2 peak. Submaximal VO2 levels exceeded 70% of VO2 peak in 30% of the subjects. Overall the mean submaximal VO2 was 51% higher than VO2 levels expected for the speed and grade consistent with severe impairment in economy of gait. There was an inverse relationship between economy of gait and 6MW (r=−0.31, P<0.01 and with the self-selected walking speed (r=−0.35, P<0.01. Thus, the impairment in economy of gait and decreased physiologic reserve result in routine walking being performed at a high percentage of VO2 peak.

  19. Singlet Oxygen Sensor Green: Photochemical Behavior in Solution and in a Mammalian Cell

    DEFF Research Database (Denmark)

    Gollmer, Anita; Arnbjerg, Jacob; Blaikie, Frances Helen

    2011-01-01

    The development of efficient and selective luminescent probes for reactive oxygen species, particularly for singlet molecular oxygen, is currently of great importance. In this study, the photochemical behavior of Singlet Oxygen Sensor Green® (SOSG), a commercially available fluorescent probe...... for singlet oxygen, was examined. Despite published claims to the contrary, the data presented herein indicate that SOSG can, in fact, be incorporated into a living mammalian cell. However, for a number of reasons, caution must be exercised when using SOSG. First, it is shown that the immediate product...... of the reaction between SOSG and singlet oxygen is, itself, an efficient singlet oxygen photosensitizer. Second, SOSG appears to efficiently bind to proteins which, in turn, can influence uptake by a cell as well as behavior in the cell. As such, incorrect use of SOSG can yield misleading data on yields...

  20. Effects of a Physical Activity Program on Cardiorespiratory Fitness and Pulmonary Function in Obese Women after Bariatric Surgery: a Pilot Study.

    Science.gov (United States)

    Onofre, Tatiana; Carlos, Renata; Oliver, Nicole; Felismino, Amanda; Fialho, Davi; Corte, Renata; da Silva, Eliane Pereira; Godoy, Eudes; Bruno, Selma

    2017-08-01

    In severely obese individuals, reducing body weight induced by bariatric surgery is able to promote a reduction in comorbidities and improve respiratory symptoms. However, cardiorespiratory fitness (CRF) reflected by peak oxygen uptake (VO 2peak ) may not improve in individuals who remain sedentary post-surgery. The objective of this study was to evaluate the effects of a physical training program on CRF and pulmonary function in obese women after bariatric surgery, and to compare them to a control group. Twelve obese female candidates for bariatric surgery were evaluated in the preoperative, 3 months postoperative (3MPO), and 6 months postoperative (6MPO) periods through anthropometry, spirometry, and cardiopulmonary exercise testing (CPX). In the 3MPO period, patients were divided into control group (CG, n = 6) and intervention group (IG, n = 6). CG received only general guidelines while IG underwent a structured and supervised physical training program involving aerobic and resistance exercises, lasting 12 weeks. All patients had a significant reduction in anthropometric measurements and an increase in lung function after surgery, with no difference between groups. However, only IG presented a significant increase (p bariatric surgery could promote a significant increase in CRF only in the trained group, yet also showing that bariatric surgery alone caused an improvement in the lung function of both groups.

  1. Cardiorespiratory fitness, pulmonary function and C-reactive protein levels in nonsmoking individuals with diabetes

    International Nuclear Information System (INIS)

    Francisco, C.O.; Catai, A.M.; Moura-Tonello, S.C.G.; Lopes, S.L.B.; Benze, B.G.; Del Vale, A.M.; Leal, A.M.O.

    2014-01-01

    The objective of this study was to evaluate cardiorespiratory fitness and pulmonary function and the relationship with metabolic variables and C-reactive protein (CRP) plasma levels in individuals with diabetes mellitus (DM). Nineteen men with diabetes and 19 age- and gender-matched control subjects were studied. All individuals were given incremental cardiopulmonary exercise and pulmonary function tests. In the exercise test, maximal workload (158.3±22.3 vs 135.1±25.2, P=0.005), peak heart rate (HR peak : 149±12 vs 139±10, P=0.009), peak oxygen uptake (VO 2peak : 24.2±3.2 vs 18.9±2.8, P<0.001), and anaerobic threshold (VO 2VT : 14.1±3.4 vs 12.2±2.2, P=0.04) were significantly lower in individuals with diabetes than in control subjects. Pulmonary function test parameters, blood pressure, lipid profile (triglycerides, HDL, LDL, and total cholesterol), and CRP plasma levels were not different in control subjects and individuals with DM. No correlations were observed between hemoglobin A1C (HbA1c), CRP and pulmonary function test and cardiopulmonary exercise test performance. In conclusion, the results demonstrate that nonsmoking individuals with DM have decreased cardiorespiratory fitness that is not correlated with resting pulmonary function parameters, HbA1c, and CRP plasma levels

  2. Health-related physical fitness and weight status in 13- to 15-year-old Latino adolescents. A pooled analysis.

    Science.gov (United States)

    García-Hermoso, Antonio; Correa-Bautista, Jorge E; Olloquequi, Jordi; Ramírez-Vélez, Robinson

    2018-05-05

    The aim of this study was to investigate the relation between health-related physical fitness and weight status in 13- to 15-year-old Latino adolescents. The final sample consisted of 73,561 adolescents aged 13-15 years (35,175 girls) from Chile (n=48,771) and Colombia (n=24,790). Cardiorespiratory and musculoskeletal fitness were measured using 20-m shuttle run (relative peak oxygen uptake - VO 2peak ) and standing broad jump test (lower body explosive strength), respectively. The International Obesity Task Force definition was used to define weight status (i.e., underweight, normal weight, overweight, and obese). The present study found an inverted J-shape relationship between body mass index, cardiorespiratory fitness, and musculoskeletal fitness in both genders and all age groups (pfitness (based on new international criterion-referenced standards) profile when compared with their normal weight peers, except in girls aged 14 (p=0.268) and 15 years (p=0.280). The present results indicate low cardiorespiratory fitness and musculoskeletal fitness levels in underweight, overweight, and obese adolescents when compared with their normal weight peers. The findings appear to suggest that exercise programs should to decrease fat mass in overweight/obese adolescents and increase muscle mass in underweight adolescents. Copyright © 2018 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  3. Effects of 16-week high-intensity interval training using upper and lower body ergometers on aerobic fitness and morphological changes in healthy men: a preliminary study.

    Science.gov (United States)

    Osawa, Yusuke; Azuma, Koichiro; Tabata, Shogo; Katsukawa, Fuminori; Ishida, Hiroyuki; Oguma, Yuko; Kawai, Toshihide; Itoh, Hiroshi; Okuda, Shigeo; Matsumoto, Hideo

    2014-01-01

    It is unclear whether combined leg and arm high-intensity interval training (HIIT) improves fitness and morphological characteristics equal to those of leg-based HIIT programs. The aim of this study was to compare the effects of HIIT using leg-cycling (LC) and arm-cranking (AC) ergometers with an HIIT program using only LC. Effects on aerobic capacity and skeletal muscle were analyzed. Twelve healthy male subjects were assigned into two groups. One performed LC-HIIT (n=7) and the other LC- and AC-HIIT (n=5) twice weekly for 16 weeks. The training programs consisted of eight to 12 sets of >90% VO2 (the oxygen uptake that can be utilized in one minute) peak for 60 seconds with a 60-second active rest period. VO2 peak, watt peak, and heart rate were measured during an LC incremental exercise test. The cross-sectional area (CSA) of trunk and thigh muscles as well as bone-free lean body mass were measured using magnetic resonance imaging and dual-energy X-ray absorptiometry. The watt peak increased from baseline in both the LC (23%±38%; PHIIT program improves aerobic capacity and muscle hypertrophy in both leg and trunk muscles.

  4. PADDLING PERFORMANCE AND RANKING POSITION IN JUNIOR SURFERS COMPETING AT THE ASSOCIATION OF SURFING PROFESSIONALS: A PILOT STUDY

    Directory of Open Access Journals (Sweden)

    Jesús Cámara

    2011-11-01

    Full Text Available Abstract  The aims of this pilot study are on one hand, to evaluate the upper body aerobic characteristics of junior surfers competing at the European branch of the Association of Surfing Professionals (ASP and on the other, to assess the relationship between the junior surfers' upper body aerobic characteristics and their ranking position. Ten surfers competing at the European junior branch of the ASP took part in the study. The maximal oxygen uptake (VO2MAX, the maximum power output (WMAX, the maximum lactate concentration [La]MAX, the maximum heart rate (HRMAX and the power output at the intensity where the lactate threshold and the onset of blood lactate accumulation are produced (WLT and WOBLA were determined during an incremental maximal test in a swim bench ergometer. It was observed a lack of a significant relationship between the ranking position and the parameters at maximal intensity (VO2PEAK, WMAX, HRMAX y [La]MAX. The WLT (W · kg-1 and the WOBLA (W · kg-1 were significantly related to ranking position (r= -0.69, p= 0.02; r= -0.72, p= 0.01, respectively.

  5. The importance of the training-induced decrease in basal cortisol concentration in the improvement in muscular performance in humans.

    Science.gov (United States)

    Grandys, M; Majerczak, J; Kulpa, J; Duda, K; Rychlik, U; Zoladz, J A

    2016-01-01

    Acute exercise-induced changes in cortisol concentration (C) and training related adaptation within hypothalamic-pituitary-adrenal (HPA) axis has been widely examined, but their influence on muscle strength performance is at best uncertain. Twenty four young healthy men were randomly assigned to an endurance training group (ET, n=12) or to a non-exercising controls (CON, n=12). ET performed supervised endurance training on cycle ergometer for 20 weeks. Endurance training program improved exercise capacity (14 % increase in power output generated at peak oxygen uptake - VO(2peak)), muscle strength performance (increase in MVC - maximal voluntary contraction - by 9 % and in TTF 50 % MVC - time to fatigue at 50 % MVC - by 21 %) and led to a decrease in basal serum C concentration (P=0.006) and an increase in basal testosterone to cortisol (T/C) and free testosterone to cortisol (fT/C) ratios (P=0.01 and P=0.02, respectively). It was found that the decrease in C concentration (deltaC) was positively correlated to the increase in local muscular endurance (deltaTTF 50 % MVC). No significant hormonal changes were seen in CON group. It is concluded that greater decrease in cortisol concentration after the endurance training is accompanied by poorer improvement in skeletal muscle performance in previously untrained subjects.

  6. Physical Activity Questionnaire for children and adolescents: English norms and cut-off points.

    Science.gov (United States)

    Voss, Christine; Ogunleye, Ayodele A; Sandercock, Gavin R H

    2013-08-01

    The Physical Activity Questionnaire for Children and Adolescents (PAQ-C/-A) provides general estimates of physical activity levels. Following recent expert recommendations for using the PAQ for population surveillance, the aim of this paper was twofold: first, to describe normative PAQ data for English youth; and second, to determine a criterion-referenced PAQ-score cut-off point. Participants (n = 7226, 53% boys, 10-15 years) completed an anglicized version of the PAQ. Peak oxygen uptake (VO2peak ) was predicted from PACER lap count according to latest FITNESSGRAM standards and categorized into "at-risk" and "no-risk" for metabolic syndrome. ROC curves were drawn for each age-sex group to identify PAQ scores, which categorized youth into "sufficiently active" versus "low-active" groups, using cardiorespiratory fitness as the criterion-referenced standard. PAQ scores were higher in boys than in girls and declined with age. Mean PAQ score was a significant, albeit relatively weak (area under the curve PAQ scores of ≥2.9 for boys and ≥2.7 for girls were identified as cut-off points, although it may be more appropriate to use lower, age-specific PAQ scores for girls of 13, 14 and 15 years (2.6, 2.4, 2.3, respectively). The normative and criterion-referenced PAQ values may be used to standardize and categorize PAQ scores in future youth population studies. © 2013 The Authors. Pediatrics International © 2013 Japan Pediatric Society.

  7. Muscle irisin response to aerobic vs HIIT in overweight female adolescents.

    Science.gov (United States)

    Archundia-Herrera, Carolina; Macias-Cervantes, Maciste; Ruiz-Muñoz, Bernardo; Vargas-Ortiz, Katya; Kornhauser, Carlos; Perez-Vazquez, Victoriano

    2017-01-01

    Exercise stimulates the production of fibronectin type III domain-containing protein 5 (FNDC5), which is cleaved to release a protein called irisin. This protein induces browning of white adipose tissue resulting in increased thermogenesis. Different studies have measured circulating irisin at baseline and in response to exercise among a wide variety of individuals; yet, regarding the effect of different exercise intensities in obese adolescent girls, limited insight is available. This study compares the effect of acute aerobic exercise of moderate intensity and high-intensity interval training (HIIT) on irisin levels in skeletal muscle and plasma of sedentary overweight or obese female adolescents. The aerobic group (n = 15) and HIIT group (n = 15) underwent anthropometric and metabolic measurements, electrocardiogram, peak oxygen uptake (VO 2peak ), and two vastus lateralis muscle biopsies before and after session of workout. The session of aerobic exercise included cycling at 65% of their peak heart rate (HRpeak) for 40 min. In the HIIT group, exercise included six bouts of 1 min at 85-95% HRpeak separated by 1 min of recovery. Irisin levels were evaluated in samples of skeletal muscle (western blot) and plasma (ELISA). The levels of expression of irisin in skeletal muscle increased significantly after a session of HIIT (p HIIT session. No increases in plasma irisin concentration were observed.

  8. High Intensity Interval Training Leads to Greater Improvements in Acute Heart Rate Recovery and Anaerobic Power as High Volume Low Intensity Training

    Science.gov (United States)

    Stöggl, Thomas L.; Björklund, Glenn

    2017-01-01

    The purpose of the current study was to explore if training regimes utilizing diverse training intensity distributions result in different responses on neuromuscular status, anaerobic capacity/power and acute heart rate recovery (HRR) in well-trained endurance athletes. Methods: Thirty-six male (n = 33) and female (n = 3) runners, cyclists, triathletes and cross-country skiers [peak oxygen uptake: (VO2peak): 61.9 ± 8.0 mL·kg−1·min−1] were randomly assigned to one of three groups (blocked high intensity interval training HIIT; polarized training POL; high volume low intensity oriented control group CG/HVLIT applying no HIIT). A maximal anaerobic running/cycling test (MART/MACT) was performed prior to and following a 9-week training period. Results: Only the HIIT group achieved improvements in peak power/velocity (+6.4%, P 0.05). Acute HRR was improved in HIIT (11.2%, P = 0.002) and POL (7.9%, P = 0.023) with no change in the HVLIT oriented control group. Conclusion: Only a training regime that includes a significant amount of HIIT improves the neuromuscular status, anaerobic power and the acute HRR in well-trained endurance athletes. A training regime that followed more a low and moderate intensity oriented model (CG/HVLIT) had no effect on any performance or HRR outcomes. PMID:28824457

  9. Acute physiological responses to recreational in-line skating in young adults.

    Science.gov (United States)

    Orepic, Paula; Mikulic, Pavle; Soric, Maroje; Ruzic, Lana; Markovic, Goran

    2014-01-01

    We examined the physiological responses to in-line skating exercise at self-selected paces in recreationally trained adults. Seven men and 10 women performed in-line skating exercise during which oxygen uptake (VO2) and heart rate (HR) were recorded continuously. Ratings of perceived exertion (RPE) and blood lactate concentration were also obtained at the end of exercise. Furthermore, subjects' peak VO2, peak HR, RPE and gas-exchange thresholds were determined in laboratory settings. The average exercise intensity during in-line skating was 90% of peak HR, 67% of peak VO2, 84% of HR reserve and 64% of VO2 reserve. When expressed as RPE and as metabolic equivalents (METs), the average exercise intensity was 13.1 RPE and 9.4 METs. Overall, these indicators of exercise intensity categorise in-line skating at self-selected paces as a vigorous physical activity. Notably, at similar VO2 values, significantly higher HR (174 ± 16 vs. 156 ± 6 bpm; pskating compared with treadmill running. We conclude that 1. recreational in-line skating induces physiological responses that are sufficient for improving and maintaining cardiovascular fitness in healthy adults, 2. HR- and RPE-based methods for quantifying the exercise intensity during in-line skating may overestimate the actual metabolic load and 3. the derivation of exercise prescriptions for in-line skating should be preferably based on specific (i.e. in-line skating) graded exhaustive exercise test.

  10. Metabolic rate and gross efficiency at high work rates in world class and national level sprint skiers.

    Science.gov (United States)

    Sandbakk, Øyvind; Holmberg, Hans-Christer; Leirdal, Stig; Ettema, Gertjan

    2010-06-01

    The present study investigated metabolic rate (MR) and gross efficiency (GE) at moderate and high work rates, and the relationships to gross kinematics and physical characteristics in elite cross-country skiers. Eight world class (WC) and eight national level (NL) male sprint cross-country skiers performed three 5-min stages using the skating G3 technique, whilst roller skiing on a treadmill. GE was calculated by dividing work rate by MR. Work rate was calculated as the sum of power against gravity and frictional rolling forces. MR was calculated using gas exchange and blood lactate values. Gross kinematics, i.e. cycle length (CL) and cycle rate (CR) were measured by video analysis. Furthermore, the skiers were tested for time to exhaustion (TTE), peak oxygen uptake (VO(2peak)), and maximal speed (V(max)) on the treadmill, and maximal strength in the laboratory. Individual performance level in sprint skating was determined by FIS points. WC skiers did not differ in aerobic MR, but showed lower anaerobic MR and higher GE than NL skiers at a given speed (all P higher V(max) and TTE (all P better technique and to technique-specific power.

  11. Optic nerve oxygen tension

    DEFF Research Database (Denmark)

    Kiilgaard, Jens Folke; Pedersen, D B; Eysteinsson, T

    2004-01-01

    The authors have previously reported that carbonic anhydrase inhibitors such as acetazolamide and dorzolamide raise optic nerve oxygen tension (ONPO(2)) in pigs. The purpose of the present study was to investigate whether timolol, which belongs to another group of glaucoma drugs called beta...

  12. Home Oxygen Therapy

    Science.gov (United States)

    ... cold it can hurt your skin. Keep a fire extinguisher close by, and let your fire department know that you have oxygen in your ... any symptoms of illness. Medicare, Medicaid, and Commercial Insurance Certain insurance policies may pay for all your ...

  13. Central oxygen pipeline failure

    African Journals Online (AJOL)

    surgical intensive care unit (ICU), with two patients on full ventilation and ... uncertainty around the cause of the failure and the restoration, .... soon as its level also falls below three tons. Should ... (properly checked and closed prior to each anaesthetic). ... in use at the time of the central oxygen pipeline failure at Tygerberg.

  14. Extracorporeal membrane oxygenation (ECMO)

    African Journals Online (AJOL)

    Extracorporeal membrane oxygenation (ECMO) is not a novel therapy in the true sense of the ... Intention-to-treat analysis showed benefit for ECMO, with a relative risk ... no doubt that VV-ECMO is an advance in medical technology, and that.

  15. Oxygen Extraction from Minerals

    Science.gov (United States)

    Muscatello, Tony

    2017-01-01

    Oxygen, whether used as part of rocket bipropellant or for astronaut life support, is a key consumable for space exploration and commercialization. In Situ Resource Utilization (ISRU) has been proposed many times as a method for making space exploration more cost effective and sustainable. On planetary and asteroid surfaces the presence of minerals in the regolith that contain oxygen is very common, making them a potential oxygen resource. The majority of research and development for oxygen extraction from minerals has been for lunar regolith although this work would generally be applicable to regolith at other locations in space. This presentation will briefly survey the major methods investigated for oxygen extraction from regolith with a focus on the current status of those methods and possible future development pathways. The major oxygen production methods are (1) extraction from lunar ilmenite (FeTiO3) with either hydrogen or carbon monoxide, (2) carbothermal reduction of iron oxides and silicates with methane, and (3) molten regolith electrolysis (MRE) of silicates. Methods (1) and (2) have also been investigated in a two-step process using CO reduction and carbon deposition followed by carbothermal reduction. All three processes have byproducts that could also be used as resources. Hydrogen or carbon monoxide reduction produce iron metal in small amounts that could potentially be used as construction material. Carbothermal reduction also makes iron metal along with silicon metal and a glass with possible applications. MRE produces iron, silicon, aluminum, titanium, and glass, with higher silicon yields than carbothermal reduction. On Mars and possibly on some moons and asteroids, water is present in the form of mineral hydrates, hydroxyl (-OH) groups on minerals, andor water adsorbed on mineral surfaces. Heating of the minerals can liberate the water which can be electrolyzed to provide a source of oxygen as well. The chemistry of these processes, some key

  16. Ocean Ridges and Oxygen

    Science.gov (United States)

    Langmuir, C. H.

    2014-12-01

    The history of oxygen and the fluxes and feedbacks that lead to its evolution through time remain poorly constrained. It is not clear whether oxygen has had discrete steady state levels at different times in Earth's history, or whether oxygen evolution is more progressive, with trigger points that lead to discrete changes in markers such as mass independent sulfur isotopes. Whatever this history may have been, ocean ridges play an important and poorly recognized part in the overall mass balance of oxidants and reductants that contribute to electron mass balance and the oxygen budget. One example is the current steady state O2 in the atmosphere. The carbon isotope data suggest that the fraction of carbon has increased in the Phanerozoic, and CO2 outgassing followed by organic matter burial should continually supply more O2 to the surface reservoirs. Why is O2 not then increasing? A traditional answer to this question would relate to variations in the fraction of burial of organic matter, but this fraction appears to have been relatively high throughout the Phanerozoic. Furthermore, subduction of carbon in the 1/5 organic/carbonate proportions would contribute further to an increasingly oxidized surface. What is needed is a flux of oxidized material out of the system. One solution would be a modern oxidized flux to the mantle. The current outgassing flux of CO2 is ~3.4*1012 moles per year. If 20% of that becomes stored organic carbon, that is a flux of .68*1012 moles per year of reduced carbon. The current flux of oxidized iron in subducting ocean crust is ~2*1012 moles per year of O2 equivalents, based on the Fe3+/Fe2+ ratios in old ocean crust compared to fresh basalts at the ridge axis. This flux more than accounts for the incremental oxidizing power produced by modern life. It also suggests a possible feedback through oxygenation of the ocean. A reduced deep ocean would inhibit oxidation of ocean crust, in which case there would be no subduction flux of oxidized

  17. Determination of maximum physiologic thyroid uptake and correlation with 24-hour RAI uptake value

    International Nuclear Information System (INIS)

    Duldulao, M.; Obaldo, J.

    2007-01-01

    Full text: In hyperthyroid patients, thyroid uptake values are overestimated, sometimes approaching or exceeding 100%. This is physiologically and mathematically impossible. This study was undertaken to determine the maximum physiologic thyroid uptake value through a proposed simple method using a gamma camera. Methodology: Twenty-two patients (17 females and 5 males), with ages ranging from 19-61 y/o (mean age ± SD; 41 ± 12), with 24-hour uptake value of >50%, clinically hyperthyroid and referred for subsequent radioactive iodine therapy were studied. The computed maximum physiologic thyroid uptake was compared with the 24-hour uptake using the paired Student t-test and evaluated using linear regression analysis. Results: The computed physiologic uptake correlated poorly with the 24-hour uptake value. However, in the male subgroup, there was no statistically significant difference between the two (p=0.77). Linear regression analysis gives the following relationship: physiologic uptake (%) = 77.76 - 0.284 (24-hour RAI uptake value). Conclusion: Provided that proper regions of interest are applied with correct attenuation and background subtraction, determination of physiologic thyroid uptake may be obtained using the proposed method. This simple method may be useful prior to I-131 therapy for hyperthyroidism especially when a single uptake determination is performed. (author)

  18. Transcriptional regulation by Ferric Uptake Regulator (Fur) in pathogenic bacteria.

    Science.gov (United States)

    Troxell, Bryan; Hassan, Hosni M

    2013-01-01

    In the ancient anaerobic environment, ferrous iron (Fe(2+)) was one of the first metal cofactors. Oxygenation of the ancient world challenged bacteria to acquire the insoluble ferric iron (Fe(3+)) and later to defend against reactive oxygen species (ROS) generated by the Fenton chemistry. To acquire Fe(3+), bacteria produce low-molecular weight compounds, known as siderophores, which have extremely high affinity for Fe(3+). However, during infection the host restricts iron from pathogens by producing iron- and siderophore-chelating proteins, by exporting iron from intracellular pathogen-containing compartments, and by limiting absorption of dietary iron. Ferric Uptake Regulator (Fur) is a transcription factor which utilizes Fe(2+) as a corepressor and represses siderophore synthesis in pathogens. Fur, directly or indirectly, controls expression of enzymes that protect against ROS damage. Thus, the challenges of iron homeostasis and defense against ROS are addressed via Fur. Although the role of Fur as a repressor is well-documented, emerging evidence demonstrates that Fur can function as an activator. Fur activation can occur through three distinct mechanisms (1) indirectly via small RNAs, (2) binding at cis regulatory elements that enhance recruitment of the RNA polymerase holoenzyme (RNAP), and (3) functioning as an antirepressor by removing or blocking DNA binding of a repressor of transcription. In addition, Fur homologs control defense against peroxide stress (PerR) and control uptake of other metals such as zinc (Zur) and manganese (Mur) in pathogenic bacteria. Fur family members are important for virulence within bacterial pathogens since mutants of fur, perR, or zur exhibit reduced virulence within numerous animal and plant models of infection. This review focuses on the breadth of Fur regulation in pathogenic bacteria.

  19. Oxygen diffusion in monazite

    Science.gov (United States)

    Cherniak, D. J.; Zhang, X. Y.; Nakamura, M.; Watson, E. B.

    2004-09