5 Clinical Trials for Various Conditions
Prolonged, high intensity work in a hot environment results in significant strain on the body, known as heat strain. Heat strain in hot occupational settings such as agriculture, fire suppression, and military work can lead to \~20% of workers exceeding the glomerular filtration rate indicated thresholds for acute kidney injury (AKI). However, it is unclear whether these individuals truly experienced AKI or if these were normal, healthy physiologic responses. To better determine if AKI occurs in the staggering number of workers previously reported, AKI biomarkers are needed in addition to kidney function markers (e.g., glomerular filtration rate) to characterize this response. The product of urinary tissue inhibitor of metalloproteinase 2 (TIMP-2) and insulin-like growth factor binding protein 7 (IGFBP7) is a promising Food and Drug Administration approved biomarker indicating risk of AKI and is currently used in hospitalized individuals. The usefulness of this biomarker in determining AKI in healthy individuals during heat strain is now beginning to be understood. Consecutive days of heat strain can result in repeated AKI, which is hypothesized to lead to chronic kidney disease. There is an epidemic of chronic kidney disease of non-traditional causes occurring in workers who undergo repeated days heat strain, including approximately 15% of outdoor workers in Central America. Of the few studies that investigated consecutive days of work in the heat, we demonstrated that participants exceed the glomerular filtration rate indicated threshold for AKI during consecutive days of heat strain. This project will determine whether \[TIMP-2 x IGFBP7\] increases during occupational relevant heat exposures in a healthy, active population. Additionally, this project will compare the impact of repeated exposures to a hot environment on risk of AKI.
The goal of this clinical trial is to learn about the processes occurring in the kidneys while under heat stress in healthy volunteers. The main questions it aims to answer are: * How do the chemicals produced by the body change under conditions of higher versus lower heat stress? * What role does a specific area of the body's metabolism, known as NAD+ metabolism, play in the body's response to heat stress, and can this response be modified by taking vitamin B3?
Life in space is completely void of physical and environmental stress. It is well known that living things need regular physical stress (e.g. exercise) to remain strong, functional and healthy. More and more research is showing that regular environmental stress, for example heat and hypoxia, can further improve physical health. Astronauts aboard the international space station (ISS) exercise for 1-2 hours every day to avoid physical deconditioning that would otherwise cause them to age rapidly in space. Although physical exercise is very effective in remedying this deconditioning, today's astronauts still have physiological changes that indicate accelerated aging. This is a cause for concern given NASA's priority to travel to mars within the next decade; a mission that will require at least double the duration in space for our astronauts. The investigators think that the complete absence of environmental stress, i.e., heat, may be contributing to the accelerated aging that occurs during spaceflight. Our study will assess the health effects of adding heat stress to exercise that could be performed in space by astronauts. The goal is to inform best practice for astronauts to avoid physical deconditioning during long-duration spaceflight. This information will also be relevant to life on earth as spaceflight is a model of inactivity here on earth. Therefore, the potential benefits of adding heat stress will likely translate to life in space and on earth.
Extreme heat causes a disproportionate number of hospitalizations and deaths in older adults relative to any other age group. Importantly, many hospitalizations and deaths are primarily due to cardiovascular events such as myocardial infarction. Previous data indicate that older adults have attenuated skin blood flow and sweating responses when exposed to heat, resulting greater increase in core body temperature. Despite these observations, relatively little is known about the risk for myocardial ischemia potentially contributing to the aforementioned higher morbidity and mortality in older adults during heat waves. The broad objective of this work is to determine the impact of ambient heat exposure on myocardial blood flow and flow reserve in young and older adults. Aim 1 will test the hypothesis that older adults exhibit attenuated myocardial flow reserve compared to young adults during heat stress. Aim 2 will determine if the percent of maximal myocardial flow reserve (assess via vasodilator stress) during heat exposure is higher in older adults compared to young adults. The expected outcome from this body of work will improve our understanding of the consequences of aging on cardiovascular responses to ambient heat stress.
Muscle sprains of the back and neck are very common. In addition to pain and antiinflammatory medications the use of either cold or hot packs has been recommended. In the current study we will compare ice packs and heat packs to see which is more effective at relieving pain from back and neck sprains while in the Emergency Department.