Thermoregulatory function during the marathon

Marathon races are performed over a broad range of environmental conditions. Hyperthermia is a primary challenge for runners in temperate and warm weather, but hypothermia can be a concern during cool-wet or cold conditions. Body temperature during the marathon is a balance between metabolic heat production and exchange with the environment described by the heat balance equation. During exercise, core temperature is proportional to the metabolic rate and largely independent of a wide range of environmental conditions. In temperate or cool conditions, a large skin-to-ambient temperature gradient facilitates radiant and convective heat loss, and reduces skin blood flow requirements, which may explain the tolerance for high core temperature observed during marathons in cool conditions. However, in warmer environments, skin temperatures and sweating rates increase. In addition, greater skin blood flow is required for heat loss, magnifying thermoregulatory and circulatory strain. The combined challenge of exercise and environment associated with marathon running can substantially challenge the human thermoregulatory system.     

Acquired pMHC I Complexes Greatly Enhance CD4~+ Th Cell’s Stimulatory Effect on CD8~+ T Cell-Mediated Diabetes in Transgenic RIP-mOVA Mice

CD4+ helper T (Th) cells play pivotal roles in induction of CD8+ CTL immunity. However, the mechanism of CD4+ T cell help delivery to CD8+ T cells in vivo is still elusive. In this study, we used ovalbumin (OVA)-pulsed dendritic cells (DCOVA) to activate OT-II mouse CD4+ T cells, and then studied the help effect of these CD4+ T cells on CD8+ cytotoxic T lymphocyte (CTL) responses. We also examined CTL mediated islet β cell destruction which led to diabetes in wild-type C57BL/6 mice and transgenic rat insuli...     

On the variability of QRS time-duration in magnetocardiographic recordings

High resolution electrocardiography (HRECG) recordings have already shown an increased beat-to-beat microvariability of the QRS duration of the terminal QRS in patients with a history of ventricular tachycardia (VT). The purpose of this study is to detect QRS-duration microvariability with magnetocardiographic (MCG) recordings in normals, patients with coronary heart disease (CHD), patients with a history of myocardial infarction (MI), and VT patients. QRS microvariability is calculated as the variance of time-shifts of single beats respectively to the average of all beats. The average over all channels of the MCG is performed. QRS microvariability was evaluated from 55-channel MCG in 15 normal persons, in 12 patients with CHD, in 13 patients with MI, and in 10 patients with VT. We found a significantly higher microvariability in patients with MI compared to normals. The highest microvariability was found in VT patients.