The effect of high-fat meals and exercise on endothelial function and triacylglycerol concentrations in adolescent boys

The thesis investigated the effect of exercise on endothelial function (measured as flow-mediated dilation (FMD)) and triacylglycerol concentrations following the ingestion of a high-fat breakfast and lunch in adolescent boys. The validity of measuring lipid and lipoprotein concentrations from a capillary blood sample, and the reproducibility of the postprandial FMD and triacylglycerol concentration responses to the high-fat meals, was established. The effects of prior continuous moderate-intensity exercise (60 min walking at 60% V ̇O2peak), repeated very short duration sprints (40 x 6 s maximal effort cycle sprints) and accumulated moderate-intensity exercise (6 x 10 min running at 70% V ̇O2peak) on endothelial function and triacylglycerol concentrations in adolescent boys were then established across three studies, each consisting of two, 2-day main trials (control and exercise). On day 1, participants were either inactive or completed the prescribed exercise. On day 2, FMD and triacylglycerol concentrations were measured prior to, and following, ingestion of a high-fat breakfast and lunch. In each control trial FMD was reduced (signifying endothelial dysfunction), compared to fasting, by 20-32% and 24-33% following the high-fat breakfast and lunch. Following continuous moderate-intensity exercise, repeated very-short duration sprints and accumulated moderate-intensity exercise these reductions were only 8% and 10% (main effect trial, P = 0.002; main effect time, P = 0.023; interaction effect trial x time, P = 0.088), 2% and 5% (main effect trial, P = 0.012; main effect time, P = 0.004; interaction effect trial x time, P = 0.003) and 1% and 3% (main effect trial, P = 0.020; main effect time, P < 0.001; interaction effect trial x time, P = 0.014) respectively. The continuous moderate-intensity exercise and repeated very short duration sprints also significantly reduced the total area under the triacylglycerol concentration versus time curve by 22% (Control vs. Exercise; 12.68 (sem 1.37) vs. 9.84 (sem 0.75) mmol L-1 6.5h, P = 0.018) and 13% (Exercise vs. Control: 8.65 (sem 0.97) vs. 9.92 (sem 1.16) mmol L-1 6.5h, P = 0.023). The accumulated moderate-intensity exercise also reduced the total area under the triacylglycerol concentration versus time curve by 11%, but this reduction was not significant (Control vs. Exercise: 10.71 (sem 0.94) vs. 9.56 (sem 0.67) mmol L-1 6.5h, respectively, P = 0.183). The experimental evidence from these studies emphasise that exercise might offer an acceptable, non-pharmacological means of influencing CHD risk when individuals are young. The results of these studies can help shape future physical activity guidelines

The accumulation of exercise and postprandial endothelial function in boys

The purpose of this study was to investigate the effect of accumulating 60min of exercise on endothelial function and triacylglycerol concentrations following the ingestion of a high-fat breakfast and lunch in 14 adolescent boys (aged 12 to 14 years). Two, 2-day main trials (control and exercise) were completed in a counter-balanced, cross-over design. Participants were inactive on day 1 of the control trial but on day 1 of the exercise trial completed 6×10min runs at 70% of peak oxygen uptake, spread over the day. On day 2, triacylglycerol concentrations and flow-mediated dilation (FMD) were measured prior to, and following, ingestion of the high-fat meals. In the control trial, FMD was reduced by 30% and 33% (P0.05). These results support the concept of accumulating physical activity for health in adolescents as the accumulated exercise attenuated the decline in FMD seen following the consumption of high-fat meals. © 2013 John Wiley & Sons A/S

Acute high-intensity interval rowing increases thrombin generation in healthy men

PURPOSE: High-intensity exercise induces several health benefits, but may acutely and transiently increase the risk of cardiovascular events due to thrombotic changes promoting blood coagulation and thrombin formation. This study examined the effects of high-intensity exercise on plasma thrombin generation and triacylglycerol concentrations. METHODS: Sixteen healthy men completed two, 2-day conditions separated by 1 week. On day 1, participants rested (control) or completed four, 3-min high-intensity rowing intervals at an average rating of perceived exertion of 17 (exercise). Venous blood samples were collected pre- and post-intervention to determine plasma thrombin generation. On day 2, participants rested and consumed a glucose load (0 h) and high-fat meal (2 h). Fifteen venous blood samples were collected between 0 and 8 h to measure plasma thrombin generation and triacylglycerol concentrations. RESULTS: On day 1, lag time was shorter and peak thrombin and endogenous thrombin potential were greater in the exercise than control condition (ES ≥ 0.37, main effect condition P ≤ 0.03), and post-intervention compared with pre-intervention (ES ≥ 0.49, main effect time P ≤ 0.003). The magnitude of the post-intervention change was greater in the exercise than control condition for all thrombin generation parameters (condition by time interaction P ≤ 0.05). On day 2, no differences in postprandial thrombin generation parameters were seen between conditions (P ≥ 0.21). The total area under the curve for triacylglycerol was lower in the exercise than control condition (ES = 0.34, P = 0.02). CONCLUSION: An acute bout of high-intensity interval rowing increased plasma thrombin generation immediately after exercise, but these differences were eliminated 16–24 h after exercise

Effect of exercise on postprandial endothelial function in adolescent boys

The ingestion of high-fat meals induces a state of endothelial dysfunction in adults. This dysfunction is attenuated by prior exercise. The response of young people to these nutritional and physiological stressors has not been established. Thus, the purpose of the present study was to investigate if a bout of moderate-intensity exercise influenced endothelial function (as indicated by flow-mediated dilation (FMD)) following the ingestion of a high-fat breakfast and lunch in adolescent boys (aged 12·6–14·3 years). Two, 2 d main trials (control and exercise) were completed by thirteen adolescent boys in a counter-balanced, cross-over design. Participants were inactive on day 1 of the control trial, but completed 60 min of walking at 60% peak oxygen uptake in the exercise trial. On day 2, endothelial function was assessed via FMD prior to, and following, ingestion of a high-fat breakfast and lunch. There was no difference in fasting FMD between the control and exercise trial (P¼0·449). In the control trial, FMD was reduced by 32% following consumption of the high-fat breakfast and by 24% following lunch. In the exercise trial, the corresponding reductions were 6 and 10 %, respectively (main effect trial, P¼0·002). These results demonstrate that moderate-intensity exercise can attenuate the decline in FMD seen following the consumption of high-fat meals in adolescent boys

Effect of repeated sprints on postprandial endothelial function and triacylglycerol concentrations in adolescent boys

This study investigated if repeated, very short duration sprints influenced endothelial function (indicated by flow-mediated dilation) and triacylglycerol concentrations following the ingestion of high-fat meals in adolescent boys. Nine adolescent boys completed two, 2-day main trials (control and exercise), in a counter-balanced, cross-over design. Participants were inactive on day 1 of the control trial but completed 40 x 6 s maximal cycle sprints on day 1 of the exercise trial. On day 2 capillary blood samples were collected and flow-mediated dilation measured prior to, and following, ingestion of a high-fat breakfast and lunch. Fasting flow-mediated dilation and plasma triacylglycerol concentration were similar in the control and exercise trial (P>0.05). In the control trial flow-mediated dilation was reduced by 20% and 27% following the high-fat breakfast and lunch; following exercise these reductions were negated (main effect trial, P<0.05; interaction effect trial x time, P<0.05). The total area under the plasma triacylglycerol concentration versus time curve was 13% lower on day 2 in the exercise trial, compared to the control trial (8.65 (0.97) vs. 9.92 (1.16) mmol·L-1·6.5h, P<0.05). These results demonstrate that repeated 6 s maximal cycle sprints can have beneficial effects on postprandial endothelial function and triacylglycerol concentrations in adolescent boys

Long-wavelength TCF-based fluorescence probes for the detection and intracellular imaging of biological thiols

Two ‘turn on’ TCF-based fluorescence probes were developed for the detection of biological thiols (TCF-GSH and TCFCl-GSH). TCF-GSH was shown to have a high sensitivity towards glutathione (GSH) with a 0.28 μM limit of detection. Unfortunately, at higher GSH concentrations the fluorescence intensity of TCF-GSH decreased and toxicity was observed for TCF-GSH in live cells. However, TCFCl-GSH was shown to be able to detect GSH at biologically relevant concentrations with a 0.45 μM limit of detection. No toxicity was found for TCFCl-GSH and a clear ‘turn on’ with good photostability was observed for the exogenous addition of GSH, Cys and HCys. Furthermore, TCFCl-GSH was used to evaluate the effects of drug treatment on the levels of GSH in live cells

Design and validation of a questionnaire about the perceptions of dual career student-athletes (ESTPORT)

Abstract The purpose of this paper was to design and validate a questionnaire about the perceptions of elite studentathletes at university relating to their dual career. In the initial creation of the instrument, constructs were defined and three dimensions were established: academic life, sporting life and sports tutor. After a process of ‘back translation’, experts (n = 8) agreed the construct to ensure content validity, the dimensions and the questionnaire questions. Statistical analysis of the items showed adequate comprehension to confirm content validity of participants (n = 30). In construct validity (n = 73), the results showed correct psychometric quality, internal consistency, reliability and adequacy of the structural model. The instrument had evidence of external validity, since the results were congruent with the main findings of the research. This questionnaire was found to be a valid and reliable assessment instrument, consisting of 84 questions (in Spanish and English language), that enables the perception of elite student-athletes to be known about their dual career whilst at university

Unknowable bodies, unthinkable sexualities: lesbian and transgender legal invisibility in the Toronto women's bathhouse raid

Although litigation involving sexual orientation and gender identity discrimination claims has generated considerable public attention in recent years, lesbian and transgender bodies and sexualities still remain largely invisible in Anglo-American courts. While such invisibility is generally attributed to social norms that fail to recognize lesbian and transgender experiences, the capacity to 'not see' or 'not know' queer bodies and sexualities also involves wilful acts of ignorance. Drawing from R. v Hornick (2002) a Canadian case involving the police raid of a women's bathhouse, this article explores how lesbian and transgender bodies and sexualities are actively rendered invisible via legal knowledge practices, norms and rationalities. It argues that limited knowledge and limited thinking not only regulate the borders of visibility and belonging, but play an active part in shaping identities, governing conduct and producing subjectivity

Diseño y validación del cuestionario de percepción de los estudiantes universitarios-deportistas de alto nivel sobre la carrera dual (ESTPORT).

El objetivo de la presente investigación fue diseñar y validar un instrumento de evaluación para conocer la percepción de los estudiantes universitarios-deportistas de alto nivel sobre la carrera dual. En la creación inicial del instrumento se definió el constructo y se establecieron tres dimensiones: carrera académica, carrera deportiva y tutor deportivo. En la validez de contenido, tras un proceso de traducción inversa, los expertos (n = 8) valoraron positivamente el constructo, las dimensiones y las preguntas cuestionario. Los resultados estadísticos de los ítems mostraron la adecuada validez de comprensión de los participantes (n = 30). En la validez de constructo (n = 73), las propiedades psicométricas mostraron la adecuada calidad psicométrica, consistencia interna, fiabilidad y bondad de ajuste. El instrumento también contó con evidencias externas de validez, dado que los resultados fueron en la línea de lo que demuestra la literatura. Por ello, este trabajo ofrece un cuestionario válido y fiable de 84 preguntas (en español y en inglés) que permite medir la percepción de los estudiantes universitarios-deportistas de alto nivel sobre la carrera dual.Actividad Física y Deport