scholarly journals Biomarker of burden: Feather corticosterone reflects energetic expenditure and allostatic overload in captive waterfowl

2017 ◽  
Vol 32 (2) ◽  
pp. 345-357 ◽  
Author(s):  
David W. Johns ◽  
Tracy A. Marchant ◽  
Graham D. Fairhurst ◽  
John R. Speakman ◽  
Robert G. Clark
Keyword(s):  
Energetic Expenditure ◽  
Feather Corticosterone

scholarly journals Assessing costs of carrying geolocators using feather corticosterone in two species of aerial insectivore

2015 ◽  
Vol 2 (5) ◽  
pp. 150004 ◽  
Author(s):  
Graham D. Fairhurst ◽  
Lisha L. Berzins ◽  
David W. Bradley ◽  
Andrew J. Laughlin ◽  
Andrea Romano ◽  
...  
Keyword(s):  
Tree Swallows ◽  
Migratory Connectivity ◽  
Fitness Costs ◽  
Negative Effects ◽  
Individual Tree ◽  
Future Studies ◽  
Aerial Insectivore ◽  
Barn Swallows ◽  
Energetic Expenditure ◽  
Feather Corticosterone

Despite benefits of using light-sensitive geolocators to track animal movements and describe patterns of migratory connectivity, concerns have been raised about negative effects of these devices, particularly in small species of aerial insectivore. Geolocators may act as handicaps that increase energetic expenditure, which could explain reported effects of geolocators on survival. We tested this ‘Energetic Expenditure Hypothesis’ in 12 populations of tree swallows ( Tachycineta bicolor ) and barn swallows ( Hirundo rustica ) from North America and Europe, using measurements of corticosterone from feathers (CORT f ) grown after deployment of geolocators as a measure of physiology relevant to energetics. Contrary to predictions, neither among- (both species) nor within-individual (tree swallows only) levels of CORT f differed with respect to instrumentation. Thus, to the extent that CORT f reflects energetic expenditure, geolocators apparently were not a strong handicap for birds that returned post-deployment. While this physiological evidence suggests that information about migration obtained from returning geolocator-equipped swallows is unbiased with regard to levels of stress, we cannot discount the possibility that corticosterone played a role in reported effects of geolocators on survival in birds, and suggest that future studies relate corticosterone to antecedent factors, such as reproductive history, and to downstream fitness costs.

scholarly journals Pharmacological inhibition of tumor anabolism and host catabolism as a cancer therapy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alejandro Schcolnik-Cabrera ◽  
Alma Chavez-Blanco ◽  
Guadalupe Dominguez-Gomez ◽  
Mandy Juarez ◽  
Ariana Vargas-Castillo ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Drug Combination ◽  
Cell Cycle Progression ◽  
De Novo ◽  
In Vivo Evaluation ◽  
Fat Loss ◽  
Normal Tissues ◽  
Animal Metabolism ◽  
Energetic Expenditure

AbstractThe malignant energetic demands are satisfied through glycolysis, glutaminolysis and de novo synthesis of fatty acids, while the host curses with a state of catabolism and systemic inflammation. The concurrent inhibition of both, tumor anabolism and host catabolism, and their effect upon tumor growth and whole animal metabolism, have not been evaluated. We aimed to evaluate in colon cancer cells a combination of six agents directed to block the tumor anabolism (orlistat + lonidamine + DON) and the host catabolism (growth hormone + insulin + indomethacin). Treatment reduced cellular viability, clonogenic capacity and cell cycle progression. These effects were associated with decreased glycolysis and oxidative phosphorylation, leading to a quiescent energetic phenotype, and with an aberrant transcriptomic landscape showing dysregulation in multiple metabolic pathways. The in vivo evaluation revealed a significant tumor volume inhibition, without damage to normal tissues. The six-drug combination preserved lean tissue and decreased fat loss, while the energy expenditure got decreased. Finally, a reduction in gene expression associated with thermogenesis was observed. Our findings demonstrate that the simultaneous use of this six-drug combination has anticancer effects by inducing a quiescent energetic phenotype of cultured cancer cells. Besides, the treatment is well-tolerated in mice and reduces whole animal energetic expenditure and fat loss.

Novel active magnetorheological knee prosthesis presents low energy consumption during ground walking

2021 ◽  
pp. 1045389X2098392
Author(s):  
Rafhael Milanezi de Andrade ◽  
Jordana Simões Ribeiro Martins ◽  
Marcos Pinotti ◽  
Antônio Bento Filho ◽  
Claysson Bruno Santos Vimieiro
Keyword(s):  
Energy Consumption ◽  
Stance Phase ◽  
Gait Cycle ◽  
Dynamic Models ◽  
Knee Prosthesis ◽  
Regenerative Braking ◽  
Harmonic Drive ◽  
Low Energy Consumption ◽  
Energetic Expenditure ◽  
Over Ground Walking

This study analyses the energy consumption of an active magnetorheological knee (AMRK) actuator that was designed for transfemoral prostheses. The system was developed as an operational motor unit (MU), which consists of an EC motor, a harmonic drive and a magnetorheological (MR) clutch, that operates in parallel with an MR brake. The dynamic models of the MR brake and MU were used to simulate the system’s energetic expenditure during over-ground walking under three different working conditions: using the complete AMRK; using just its motor-reducer, to operate as a common active knee prosthesis (CAKP), and using just the MR brake, to operate as a common semi-active knee prosthesis (CSAKP). The results are used to compare the MR devices power consumptions with that of the motor-reducer. As previously hypothesized, to use the MR brake in the swing phase is more energetically efficient than using the motor-reducer to drive the joint. Even if using the motor-reducer in regenerative braking mode during the stance phase, the differences in power consumption among the systems are remarkable. The AMRK expended 16.3 J during a gait cycle, which was 1.6 times less than the energy expenditure of the CAKP (26.6 J), whereas the CSAKP required just 6.0 J.

Physiological responses and energy expenditure during competitive fencing

2014 ◽  
Vol 39 (3) ◽  
pp. 324-328 ◽  
Author(s):  
Raffaele Milia ◽  
Silvana Roberto ◽  
Marco Pinna ◽  
Girolamo Palazzolo ◽  
Irene Sanna ◽  
...  
Keyword(s):  
Heart Rate ◽  
Energy Expenditure ◽  
Oxygen Uptake ◽  
Blood Lactate ◽  
Carbon Dioxide Production ◽  
Maximum Value ◽  
Average Group ◽  
Aerobic Energy Metabolism ◽  
Olympic Sport ◽  
Energetic Expenditure

Fencing is an Olympic sport in which athletes fight one against one using bladed weapons. Contests consist of three 3-min bouts, with rest intervals of 1 min between them. No studies investigating oxygen uptake and energetic demand during fencing competitions exist, thus energetic expenditure and demand in this sport remain speculative. The aim of this study was to understand the physiological capacities underlying fencing performance. Aerobic energy expenditure and the recruitment of lactic anaerobic metabolism were determined in 15 athletes (2 females and 13 males) during a simulation of fencing by using a portable gas analyzer (MedGraphics VO2000), which was able to provide data on oxygen uptake, carbon dioxide production and heart rate. Blood lactate was assessed by means of a portable lactate analyzer. Average group energetic expenditure during the simulation was (mean ± SD) 10.24 ± 0.65 kcal·min−1, corresponding to 8.6 ± 0.54 METs. Oxygen uptakeand heart rate were always below the level of anaerobic threshold previously assessed during the preliminary incremental test, while blood lactate reached its maximum value of 6.9 ± 2.1 mmol·L−1 during the final recovery minute between rounds. Present data suggest that physical demand in fencing is moderate for skilled fencers and that both aerobic energy metabolism and anaerobic lactic energy sources are moderately recruited. This should be considered by coaches when preparing training programs for athletes.

scholarly journals Feather corticosterone levels are not correlated with health or plumage coloration in juvenile house finches

2018 ◽  
Vol 124 (2) ◽  
pp. 157-164 ◽  
Author(s):  
Tuul Sepp ◽  
Steve Desaivre ◽  
Adam Z Lendvai ◽  
József Németh ◽  
Kevin J McGraw ◽  
...  
Keyword(s):  
Plumage Coloration ◽  
House Finches ◽  
Feather Corticosterone

scholarly journals Effect of muscle mass and intensity of isometric contraction on heart rate

2000 ◽  
Vol 88 (2) ◽  
pp. 487-492 ◽  
Author(s):  
José M. Gálvez ◽  
Juan P. Alonso ◽  
Luis A. Sangrador ◽  
Gonzalo Navarro
Keyword(s):  
Heart Rate ◽  
Muscle Mass ◽  
Rate Increase ◽  
Isometric Exercise ◽  
Heart Rate Increase ◽  
Maximal Force ◽  
Wheel Turn ◽  
Obese Subjects ◽  
Energetic Expenditure ◽  
Handgrip Contractions

The purpose of this study was to determine the effect of muscle mass and the level of force on the contraction-induced rise in heart rate. We conducted an experimental study in a sample of 28 healthy men between 20 and 30 yr of age (power: 95%, α: 5%). Smokers, obese subjects, and those who performed regular physical activity over a certain amount of energetic expenditure were excluded from the study. The participants exerted two types of isometric contractions: handgrip and turning a 40-cm-diameter wheel. Both were sustained to exhaustion at 20 and 50% of maximal force. Twenty-five subjects finished the experiment. Heart rate increased a mean of 15.1 beats/min [95% confidence interval (CI): 5.5–24.6] from 20 to 50% handgrip contractions, and 20.7 beats/min (95% CI: 11.9–29.5) from 20 to 50% wheel-turn contractions. Heart rate also increased a mean of 13.3 beats/min (95% CI: 10.4–16.1) from handgrip to wheel-turn contractions at 20% maximal force, and 18.9 beats/min (95% CI: 9.8–28.0) from handgrip to wheel-turn contractions at 50% maximal force. We conclude that the magnitude of the heart rate increase during isometric exercise is related to the intensity of the contraction and the mass of the contracted muscle.

scholarly journals Mechanical evidence that flamingos can support their body on one leg with little active muscular force

2017 ◽  
Vol 13 (5) ◽  
pp. 20160948 ◽  
Author(s):  
Young-Hui Chang ◽  
Lena H. Ting
Keyword(s):  
Body Weight ◽  
Joint Torque ◽  
Body Sway ◽  
Active Muscle ◽  
Reduced Body ◽  
Weight Support ◽  
Energetic Expenditure ◽  
Distal Joint ◽  
Support Body Weight ◽  
Muscle Contractile

Flamingos (Phoenicopteridae) often stand and sleep on one leg for long periods, but it is unknown how much active muscle contractile force they use for the mechanical demands of standing on one leg: body weight support and maintaining balance. First, we demonstrated that flamingo cadavers could passively support body weight on one leg without any muscle activity while adopting a stable, unchanging, joint posture resembling that seen in live flamingos. By contrast, the cadaveric flamingo could not be stably held in a two-legged pose, suggesting a greater necessity for active muscle force to stabilize two-legged versus one-legged postures. Our results suggest that flamingos engage a passively engaged gravitational stay apparatus (proximally located) for weight support during one-legged standing. Second, we discovered that live flamingos standing on one leg have markedly reduced body sway during quiescent versus alert behaviours, with the point of force application directly under the distal joint, reducing the need for muscular joint torque. Taken together, our results highlight the possibility that flamingos stand for long durations on one leg without exacting high muscular forces and, thus, with little energetic expenditure.

scholarly journals Physiological and cognitive consequences of a daily 26 h photoperiod in a primate : exploring the underlying mechanisms of the circadian resonance theory

2020 ◽  
Vol 287 (1931) ◽  
pp. 20201079 ◽  
Author(s):  
Clara Hozer ◽  
Fabien Pifferi
Keyword(s):  
Body Temperature ◽  
Cycle Length ◽  
Biological Clock ◽  
Resonance Theory ◽  
Marginal Costs ◽  
Natural Photoperiod ◽  
Underlying Mechanisms ◽  
Energetic Expenditure ◽  
First Time ◽  
Human Primate

The biological clock expresses circadian rhythms, whose endogenous period (tau) is close to 24 h. Daily resetting of the circadian clock to the 24 h natural photoperiod might induce marginal costs that would accumulate over time and forward affect fitness. It was proposed as the circadian resonance theory. For the first time, we aimed to evaluate these physiological and cognitive costs that would partially explain the mechanisms of the circadian resonance hypothesis. We evaluated the potential costs of imposing a 26 h photoperiodic regimen compared to the classical 24 h entrainment measuring several physiological and cognitive parameters (body temperature, energetic expenditure, oxidative stress, cognitive performances) in males of a non-human primate ( Microcebus murinus ), a nocturnal species whose endogenous period is about 23.5 h. We found significant higher resting body temperature and energy expenditure and lower cognitive performances when the photoperiodic cycle length was 26 h. Together these results suggest that a great deviation of external cycles from tau leads to daily greater energetic expenditure, and lower cognitive capacities. To our knowledge, this study is the first to highlight potential mechanisms of circadian resonance theory.

scholarly journals Effects of Dark Brooder Rearing and Age on Hypothalamic Vasotocin and Feather Corticosterone Levels in Laying Hens

2020 ◽  
Vol 7 ◽  
Author(s):  
Rebecca E. Nordquist ◽  
Elisabeth C. Zeinstra ◽  
Alyssa Dougherty ◽  
Anja B. Riber
Keyword(s):  
Laying Hens ◽  
Feather Corticosterone
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