57 research outputs found
The importance of measuring body composition in professional football players: A commentary
Professional football players are not considered to be excessively fat, but there is continuous
pressure made by managers, coaches and physiotherapists to monitor player’s body
composition to help reach optimal performance potential. Consequently, it is not uncommon
for sport scientists to assume responsibility for monitoring and managing their players’ body
composition over the playing season. As body fat is one of the main factors affecting body
composition, the knowledge and understanding of whole body density and how it inluences
the body could be useful to quantify the effectiveness of a prescribed training programme and/
or optimal performance potential
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Redox Regulation of Cardiac ASK1 (Apoptosis Signal-Regulating Kinase 1) Controls p38-MAPK (Mitogen-Activated Protein Kinase) and Orchestrates Cardiac Remodeling to Hypertension.
Systemic hypertension increases cardiac workload causing cardiomyocyte hypertrophy and increased cardiac fibrosis. An underlying feature is increased production of reactive oxygen species. Redox-sensitive ASK1 (apoptosis signal-regulating kinase 1) activates stress-regulated protein kinases (p38-MAPK [mitogen-activated protein kinases] and JNKs [c-Jun N-terminal kinases]) and promotes fibrosis in various tissues. Here, we determined the specificity of ASK1 signaling in the heart, with the hypothesis that ASK1 inhibitors may be used to manage fibrosis in hypertensive heart disease. Using immunoblotting, we established that moderate levels of H2O2 activate ASK1 in neonatal rat cardiomyocytes and perfused rat hearts. ASK1 was activated during ischemia in adult rat hearts, but not on reperfusion, consistent with activation by moderate (not high) reactive oxygen species levels. In contrast, IL (interleukin)-1β activated an alternative kinase, TAK1 (transforming growth factor-activated kinase 1). ASK1 was not activated by IL1β in cardiomyocytes and activation in perfused hearts was due to increased reactive oxygen species. Selonsertib (ASK1 inhibitor) prevented activation of p38-MAPKs (but not JNKs) by oxidative stresses in cultured cardiomyocytes and perfused hearts. In vivo (C57Bl/6J mice with osmotic minipumps for drug delivery), selonsertib (4 mg/[kg·d]) alone did not affect cardiac function/dimensions (assessed by echocardiography). However, it suppressed hypertension-induced cardiac hypertrophy resulting from angiotensin II (0.8 mg/[kg·d], 7d), with inhibition of Nppa/Nppb mRNA upregulation, reduced cardiomyocyte hypertrophy and, notably, significant reductions in interstitial and perivascular fibrosis. Our data identify a specific reactive oxygen species→ASK1→p38-MAPK pathway in the heart and establish that ASK1 inhibitors protect the heart from hypertension-induced cardiac remodeling. Thus, targeting the ASK1→p38-MAPK nexus has potential therapeutic viability as a treatment for hypertensive heart disease
Measurement reliability and precision of anthropometric measures for the estimation of whole body density in professional football players
Introduction: It is not uncommon to encounter measurement reliability issues, yet when they are required to develop practical
calibration models to estimate whole body density the reliability of anthropometric measures is imperative.
Materials and Methods: Data was gathered from n=206 male professional footballers ( ±s; age = 24.1±5.4 years, body mass =
78.8±8.4 kg and stretched stature = 180.1±7.0 cm). Reliability of n=28 anthropometric variables (skinfolds, girths, breadths, depths,
widths, residual lung volume, air displacement plethysmography and hydrostatic weighing) was investigated by applying Technical
Error of Measurement (TEM%) and the Limits of Agreement (LoA) method.
Results: TEM% indicated a range of 6.5-1.0% and 3.8-0.6% and the study’s a priori criterion was set at ±3.8% for LoA and were
statistically significant (P < 0.001). The contentious measurements of the iliac crest, supraspinale and anterior thigh skinfold, chest
and hip girth and biiliocristal breadth indicated z scores values for R2 between 0.006-0.022% and exhibited significant bias (P=<
0.05) and possible heteroscedasticity issues with highest r values of 0.611 and R2
(%) coefficients of 37.3%.
Discussion: Test-retest values demonstrated agreement and reliability to be of practical use with this population
Agreement and validity of existing anthropometric calibration models to estimate whole body density in male professional football players
Introduction
To date no calibration models exist to estimate whole body density (Db) of professional footballers, as such the development of
practical anthropometric calibration models to make sound body composition judgements is imperative. The aim of this study was
to investigate the agreement and validity of estimating Db from 15 existing calibration models through comparison to a criterion
method of hydrostatic weighing (HW) in male professional footballers.
Materials and Methods
Data were gathered from a total of n=206 professional football participants (x±s; age=24.1±5.4-years, body mass=78.8±8.4 kg,
stature=180.1±7.0 cm, Db 1.075±0.01 g.ml-1). Bland and Altman limits of agreement (LoA) approaches were used to determine
bias and random variation derived from the calibration models.
Results
Bias and random errors for the published calibration models ranged from -0.005 to +0.015 g.ml-1 and 1.012 to 1.090 g.ml-1 respectively. A priori criterion (±3.8% p=<0.05 (g.ml-1)) was set as acceptable limits for the LoA method of which 13 calibration models
found that (on average) estimated Db derived from HW was greater than Db derived from the models.
Discussion
A rank order of LoA identified the best model to use, however, LoA were not narrow enough for measurements to be of practical
use and in most instances, selected models are not appropriate for estimating Db in male professional footballers
Agreement and validity of existing anthropometric calibration models to estimate whole body density in male professional football players
Introduction
To date no calibration models exist to estimate whole body density (Db) of professional footballers, as such the development of
practical anthropometric calibration models to make sound body composition judgements is imperative. The aim of this study was
to investigate the agreement and validity of estimating Db from 15 existing calibration models through comparison to a criterion
method of hydrostatic weighing (HW) in male professional footballers.
Materials and Methods
Data were gathered from a total of n=206 professional football participants (x±s; age=24.1±5.4-years, body mass=78.8±8.4 kg,
stature=180.1±7.0 cm, Db 1.075±0.01 g.ml-1). Bland and Altman limits of agreement (LoA) approaches were used to determine
bias and random variation derived from the calibration models.
Results
Bias and random errors for the published calibration models ranged from -0.005 to +0.015 g.ml-1 and 1.012 to 1.090 g.ml-1 respectively. A priori criterion (±3.8% p=<0.05 (g.ml-1)) was set as acceptable limits for the LoA method of which 13 calibration models
found that (on average) estimated Db derived from HW was greater than Db derived from the models.
Discussion
A rank order of LoA identified the best model to use, however, LoA were not narrow enough for measurements to be of practical
use and in most instances, selected models are not appropriate for estimating Db in male professional footballers
The Dilemma of Medical Marijuana Use by Rheumatology Patients
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/107384/1/acr22267.pd
ExoMol line lists - XLIV. IR and UV line list for silicon monoxide (SiO)
A new silicon monoxide (28Si16O) line list covering infrared, visible and ultraviolet regions called SiOUVenIR is presented. This line list extends the infrared EBJT ExoMol line list by including vibronic transitions to the A 1Πand E 1Σ+ electronic states. Strong perturbations to the A 1Πband system are accurately modelled through the treatment of 6 dark electronic states: C 1Σ−, D 1Δ, a 3Σ+, b 3Π, e 3Σ− and d 3Δ. Along with the X 1Σ+ ground state, these 9 electronic states were used to build a comprehensive spectroscopic model of SiO using a combination of empirical and ab initio curves, including the potential energy (PE), spin-orbit (SO), electronic angular momentum (EAM) and (transition) dipole moment curves. The ab initio PE and coupling curves, computed at the multireference configuration interaction (MRCI) level of theory, were refined by fitting their analytical representations to 2617 experimentally derived SiO energy levels determined from 97 vibronic bands belonging to the X–X, E–X and A–X electronic systems through the MARVEL procedure. 112 observed forbidden transitions from the C–X, D–X, e–X, and d–X bands were assigned using our predictions, and these could be fed back into the MARVEL procedure. The SiOUVenIR line list was computed using published ab initio transition dipole moments for the E–X and A–X bands; the line list is suitable for temperatures up to 10 000 K and for wavelengths longer than 140 nm. SiOUVenIR is available from www.exomol.com and the CDS database
ExoMol line lists - XLIV. IR and UV line list for silicon monoxide (SiO)
A new silicon monoxide (28Si16O) line list covering infrared, visible and ultraviolet regions called SiOUVenIR is presented. This line list extends the infrared EBJT ExoMol line list by including vibronic transitions to the A 1Πand E 1Σ+ electronic states. Strong perturbations to the A 1Πband system are accurately modelled through the treatment of 6 dark electronic states: C 1Σ−, D 1Δ, a 3Σ+, b 3Π, e 3Σ− and d 3Δ. Along with the X 1Σ+ ground state, these 9 electronic states were used to build a comprehensive spectroscopic model of SiO using a combination of empirical and ab initio curves, including the potential energy (PE), spin-orbit (SO), electronic angular momentum (EAM) and (transition) dipole moment curves. The ab initio PE and coupling curves, computed at the multireference configuration interaction (MRCI) level of theory, were refined by fitting their analytical representations to 2617 experimentally derived SiO energy levels determined from 97 vibronic bands belonging to the X–X, E–X and A–X electronic systems through the MARVEL procedure. 112 observed forbidden transitions from the C–X, D–X, e–X, and d–X bands were assigned using our predictions, and these could be fed back into the MARVEL procedure. The SiOUVenIR line list was computed using published ab initio transition dipole moments for the E–X and A–X bands; the line list is suitable for temperatures up to 10 000 K and for wavelengths longer than 140 nm. SiOUVenIR is available from www.exomol.com and the CDS database
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The anti-cancer drug dabrafenib is not cardiotoxic and inhibits cardiac remodelling and fibrosis in a murine model of hypertension.
Raf kinases signal via extracellular signal-regulated kinases 1/2 (ERK1/2) to drive cell division. Since activating mutations in BRAF (B-Raf proto-oncogene, serine/threonine kinase) are highly oncogenic, BRAF inhibitors including dabrafenib have been developed for cancer. Inhibitors of ERK1/2 signalling used for cancer are cardiotoxic in some patients, raising the question of whether dabrafenib is cardiotoxic. In the heart, ERK1/2 signalling promotes not only cardiomyocyte hypertrophy and is cardioprotective but also promotes fibrosis. Our hypothesis is that ERK1/2 signalling is not required in a non-stressed heart but is required for cardiac remodelling. Thus, dabrafenib may affect the heart in the context of, for example, hypertension. In experiments with cardiomyocytes, cardiac fibroblasts and perfused rat hearts, dabrafenib inhibited ERK1/2 signalling. We assessed the effects of dabrafenib (3 mg/kg/d) on male C57BL/6J mouse hearts in vivo. Dabrafenib alone had no overt effects on cardiac function/dimensions (assessed by echocardiography) or cardiac architecture. In mice treated with 0.8 mg/kg/d angiotensin II (AngII) to induce hypertension, dabrafenib inhibited ERK1/2 signalling and suppressed cardiac hypertrophy in both acute (up to 7 d) and chronic (28 d) settings, preserving ejection fraction. At the cellular level, dabrafenib inhibited AngII-induced cardiomyocyte hypertrophy, reduced expression of hypertrophic gene markers and almost completely eliminated the increase in cardiac fibrosis both in interstitial and perivascular regions. Dabrafenib is not overtly cardiotoxic. Moreover, it inhibits maladaptive hypertrophy resulting from AngII-induced hypertension. Thus, Raf is a potential therapeutic target for hypertensive heart disease and drugs such as dabrafenib, developed for cancer, may be used for this purpose
Aristophanes and De Ste. Croix: The value of old comedy as evidence for Athenian popular culture
De Ste. Croix famously argued that Aristophanes had a conservative political outlook and attempted to use his comedies to win over lower-class audiences to this minority point of view. The ongoing influence of his interpretation has meant that old comedy has been largely ignored in the historiography of Athenian popular culture. This article extends earlier critiques of de Ste. Croix by systematically comparing how Aristophanes and the indisputably popular genre of fourth-century oratory represented the social classes of the Athenians and political leaders. The striking parallels between the two suggest that Aristophanes, far from advocating a minority position, exploited the rich and, at times, contradictory views of lower-class citizens for comic and ultimately competitive ends. As a consequence his plays are valuable evidence for Athenian popular culture and help to correct the markedly fourth-century bias in the writing of Athenian cultural history
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