Sports Science and Efforts towards Sub-Two Hour Marathon Performance

Performance in different athletic activities has continued to improve over time, with some athletes from diverse parts of the world registering new world records from time to time. With stiff competition from athletes from different parts of the world, constant upgrading of sports science based approaches to training and competition are employed to achieve more success. However, some approaches used to improve sports performance may pose ethical concerns and may challenge sports as a concept of celebrating natural human abilities. This book chapter interrogates the factors associated with efforts towards improvement of performance in endurance sports events, with a specific focus on marathon races, and the future implications for training, competition, and the nature of sports. While the interplay between nature and nurture determines the unique psychophysiological responses to training and competition, technological exploits leading to advanced sports products coupled with favourable natural and/or manipulated internal (body) and external environmental conditions will ensure continued improvement in performance. However, there is a need to censor commercial interest as well as safeguard safety and the nature of sports as a medium to celebrate natural human abilities

Omentin Prevents Myocardial Ischemic Injury Through AMP-Activated Protein Kinase- and Akt-Dependent Mechanisms

ObjectivesThis study examined the impact of omentin on myocardial injury in a mouse model of ischemia/reperfusion (I/R) and explored its underlying mechanisms.BackgroundObesity is a major risk factor for ischemic heart disease. Omentin is a circulating adipokine that is down-regulated by obesity.MethodsIn patients who underwent successful reperfusion treatment after acute myocardial infarction, cardiac function and perfusion defect were assessed by using scintigraphic images. Mice were subjected to myocardial ischemia followed by reperfusion.ResultsThis study found that high levels of plasma omentin were associated with improvement of heart damage and function after reperfusion therapy in patients with acute myocardial infarction. Systemic administration of human omentin to mice led to a reduction in myocardial infarct size and apoptosis after I/R, which was accompanied by enhanced phosphorylation of AMP-activated protein kinase (AMPK) and Akt in the ischemic heart. Fat-specific overexpression of human omentin also resulted in reduction of infarct size after I/R. Blockade of AMPK or Akt activity reversed omentin-induced inhibition of myocardial ischemic damage and apoptosis in mice. In cultured cardiomyocytes, omentin suppressed hypoxia/reoxygenation-induced apoptosis, which was blocked by inactivation of AMPK or Akt.ConclusionsOur data indicate that omentin functions as an adipokine that ameliorates acute ischemic injury in the heart by suppressing myocyte apoptosis through both AMPK- and Akt-dependent mechanisms

Surgical treatment for secondary aortoesophageal fistula after prosthetic aortic replacement: A report of four cases.

Introduction:With the increase of thoracic aortic aneurysm surgery and thoracic endovascular aortic repair, secondary aortoesophageal fistula (AEF) has been reported. However, the treatment strategy for AEF remains controversial.Presentation of cases:Four patients who had undergone prosthetic aortic replacement for thoracic aortic aneurysm 4-36 months previously, were hospitalized with sepsis-like symptoms. They were diagnosed with aortic prosthetic graft infection after computed tomography revealed ectopic gas around the prosthesis. After that, esophagogastroduodenoscopy revealed an esophageal perforation, so we diagnosed AEF. They received medication and stepwise surgery; 1 patient was discharged, 2 remain hospitalized, and 1 died.Discussion:Some reports have suggested that combined surgery provides better outcomes for AEF. Infection may be controlled by esophagectomy and antibiotic treatment, so prosthesis replacement is not always necessary. However, we should note that infection between a prosthetic graft and the native aorta brings a danger of pseudoaneurysm of the anastomosis.With the increase of thoracic aortic aneurysm surgery and thoracic endovascular aortic repair, secondary aortoesophageal fistula (AEF) has been reported. However, the treatment strategy for AEF remains controversial.Four patients who had undergone prosthetic aortic replacement for thoracic aortic aneurysm 4-36 months previously, were hospitalized with sepsis-like symptoms. They were diagnosed with aortic prosthetic graft infection after computed tomography revealed ectopic gas around the prosthesis. After that, esophagogastroduodenoscopy revealed an esophageal perforation, so we diagnosed AEF. They received medication and stepwise surgery; 1 patient was discharged, 2 remain hospitalized, and 1 died.Some reports have suggested that combined surgery provides better outcomes for AEF. Infection may be controlled by esophagectomy and antibiotic treatment, so prosthesis replacement is not always necessary. However, we should note that infection between a prosthetic graft and the native aorta brings a danger of pseudoaneurysm of the anastomosis.Conclusion:Based on our experience we conclude that surgery performed stepwise along with infection control and general health improvement is a valid treatment strategy for secondary AEF after prosthetic aortic replacement

Rice immediately adapts the dynamics of photosynthates translocation to roots in response to changes in soil water environment

Rice is susceptible to abiotic stresses such as drought stress. To enhance drought resistance, elucidating the mechanisms by which rice plants adapt to intermittent drought stress that may occur in the field is an important requirement. Roots are directly exposed to changes in the soil water condition, and their responses to these environmental changes are driven by photosynthates. To visualize the distribution of photosynthates in the root system of rice plants under drought stress and recovery from drought stress, we combined X-ray computed tomography (CT) with open type positron emission tomography (OpenPET) and positron-emitting tracer imaging system (PETIS) with 11C tracer. The short half-life of 11C (20.39 min) allowed us to perform multiple experiments using the same plant, and thus photosynthate translocation was visualized as the same plant was subjected to drought stress and then re-irrigation for recovery. The results revealed that when soil is drier, 11C-photosynthates mainly translocated to the seminal roots, likely to promote elongation of the root with the aim of accessing water stored in the lower soil layers. The photosynthates translocation to seminal roots immediately stopped after rewatering then increased significantly in crown roots. We suggest that when rice plant experiencing drought is re-irrigated from the bottom of pot, the destination of 11C-photosynthates translocation immediately switches from seminal root to crown roots. We reveal that rice roots are responsive to changes in soil water conditions and that rice plants differentially adapts the dynamics of photosynthates translocation to crown roots and seminal roots depending on soil conditions

Murine CD4+ T Cell Responses Are Inhibited by Cytotoxic T Cell-Mediated Killing of Dendritic Cells and Are Restored by Antigen Transfer

Cytotoxic T lymphocytes (CTL) provide protection against pathogens and tumors. In addition, experiments in mouse models have shown that CTL can also kill antigen-presenting dendritic cells (DC), reducing their ability to activate primary and secondary CD8+ T cell responses. In contrast, the effects of CTL-mediated killing on CD4+ T cell responses have not been fully investigated. Here we use adoptive transfer of TCR transgenic T cells and DC immunization to show that specific CTL significantly inhibited CD4+ T cell proliferation induced by DC loaded with peptide or low concentrations of protein antigen. In contrast, CTL had little effect on CD4+ T cell proliferation induced by DC loaded with high protein concentrations or expressing antigen endogenously, even if these DC were efficiently killed and failed to accumulate in the lymph node (LN). Residual CD4+ T cell proliferation was due to the transfer of antigen from carrier DC to host APC, and predominantly involved skin DC populations. Importantly, the proliferating CD4+ T cells also developed into IFN-γ producing memory cells, a property normally requiring direct presentation by activated DC. Thus, CTL-mediated DC killing can inhibit CD4+ T cell proliferation, with the extent of inhibition being determined by the form and amount of antigen used to load DC. In the presence of high antigen concentrations, antigen transfer to host DC enables the generation of CD4+ T cell responses regardless of DC killing, and suggests mechanisms whereby CD4+ T cell responses can be amplified