60 Clinical Trials for Various Conditions
The purpose of this project is to examine key mechanisms contributing to sex-differences in hypoxic vasodilation and the impact of obesity, with particular emphasis on the sympathetic nervous system.
The purpose of this project is to examine the impact of increases in brain insulin on sympathetic nervous system activity, as well as peripheral and cerebral blood flow in humans.
The purpose of this study is to collect data about the efficacy of utilizing distal topical heat application for dilatation of the radial artery. Transradial arterial access is widely accepted as the standard of care for cardiac catheterization procedures due to its increased patient comfort and significantly decreased risk of major vascular complications, and has been recently utilized in increasing volume by the interventional radiology community throughout the world. Due to the small size of the radial artery, catheterization may sometimes be technically difficult. Pre-procedure dilatation can make catheterization significantly easier, and studies have demonstrated the successful ability to dilate the radial artery with the use of topical nitroglycerin and lidocaine. However, the investigators hypothesize that utilizing topical heat applied distally can create a physiologic vasodilatation similar to that created with nitroglycerin and lidocaine, but at a significantly lower cost and with less risk due to no need for application of a medication which has a systemic effect with known side effects. The purpose of this study is to test the efficacy of radial artery vasodilatation with distal topical heat application.
The growing population of obese adults is predicted to create a large public health burden in the next few decades. This study examines function of small blood vessels providing blood flow to skeletal muscles, to test if younger obese individuals (≤40 years old, BMI \>30) are already displaying reductions in blood vessel function. This study will test if the signals blood vessels use to increase blood flow are changing in these same subjects. Findings from this study may help create treatments to delay or prevent some of the negative effects of obesity on vascular health.
The goal of this clinical trial is to compare lidocaine without epinephrine to papaverine a known vasodilatory agent, in creating improved motor strength in patients with drop foot involving an entrapment of the Common Peroneal Nerve. This phenomenon has been named the Phoenix Sign and is a very specific peripheral nerve block. Researchers will compare the effects of the above agent for pre and post infiltration changes in motor strength. Participants will: * Will be randomized to one of either agents already listed * After receiving the ultrasound guided injection, motor testing will be evaluated in 4-6 minutes with manual motor strength testing of the anterior compartment muscles. * No additional follow will be required
The increase in skin blood flow in response to rapid local heating of the skin (i.e., cutaneous vasodilation) is commonly used to assess nitric oxide (NO)-dependent dilation and overall microvascular function. Historically, rapid local heating to 42°C was considered the standard approach for these assessments. More recently, many investigators have adopted rapid local to 39°C instead, based on its larger dependency on NO and therefore improved ability to quantify NO-dependent dilation without the use of pharmacological techniques. However, to date, only one direct methodological comparison between these protocols has been performed. In this study, the investigators use the blood vessels in the skin as a representative vascular bed for examining mechanisms of microvascular dysfunction in humans. Using a minimally invasive technique (intradermal microdialysis for the local delivery of pharmaceutical agents) they examine the blood vessels in a nickel-sized area of the skin in young adults ages 18 - 30 years old. Local heating of the skin at the microdialysis sites is used to explore differences in mechanisms governing microvascular control. As a compliment to these measurements, the investigators also have participants fill out a variety of surveys to assess things such as sleep quality, physical activity, daily stressors, etc.
The goal of this clinical trial is to test the effects of MitoQ supplementation in older adults and frail older adults with physical dysfunction and/or cognitive dysfunction. The main question\[s\] it aims to answer are: * To compare vascular function, oxidative stress levels, and physical and cognitive function among older adults and frail older adults with physical and cognitive dysfunction * To determine whether MitoQ supplementation has the potential to improve vascular function in central and cerebral vessels * To determine whether MitoQ supplementation can enhance physical and cognitive capabilities.
The Vendys II, an FDA-approved device, uses finger digital thermal monitoring (DTM) after a period of blood flow restriction to evaluate vascular health. This study will evaluate the feasibility of using this device to measure the Vascular Reactivity Index (VRI) in children and adolescents/young adults (AYA) undergoing hematopoietic cell transplantation (HCT).
This is a prospective pilot study in which the effects of ascorbic acid administration are investigated in adult patients undergoing cardiac surgical procedures requiring cardiopulmonary bypass (CPB). Ascorbic acid (Vitamin C) is an essential cofactor in the biosynthesis of catecholamines, and critically ill patients are known to be ascorbate-deficient. In addition, cardiopulmonary bypass (CPB) decreases ascorbic acid concentrations. Cardiac vasoplegia is the loss of vascular tone despite adequate volume status and cardiac output, occurring commonly in patients after CPB. This necessitates the administration of vasopressors and alternative agents which can have deleterious effects. The administration of ascorbic acid to cardiac surgical patients may improve microcirculatory function, enhance endogenous catecholamine levels and decrease the need for exogenous vasopressor support.
Previous research has identified adenosine triphosphate (ATP) as an important vasodilator that is released from red blood cells during exercise and exposure to hypoxic environments in adult humans. Further, older adults appear to have lower blood flow during both of these stressors and also have lower amounts of ATP released from their red blood cells. However, the contribution of ATP to vasodilation in response to exercise and hypoxia is currently unknown due to the lack of an effective ATP receptor antagonist. We aim to determine whether Vitamin B6 or its metabolite, Pyridoxal-5-Phosphate (PLP) is an effective ATP receptor antagonist.
The EAGLE study is a Phase 3, open-label, multi-center, two-part, single-arm study of GeNOsyl(R) delivery system(s) to evaluate if inhaled nitric oxide-induced vasodilation predicts successful wean from parenteral prostacyclin (PGI) in subjects with World Health Organization (WHO) Group 1 pulmonary arterial hypertension (PAH) undergoing a medically necessary right heart catheterization (RHC). All subjects enrolled in the study will undergo an attempt to wean from parenteral PGI per standard of care.
Nitrous oxide (N2O) is a gas that is normally used to take away pain and anxiety during painful medical procedures. However, one of its effects is to also make veins appear larger and more visible. This is useful when there is a patient who needs to have an intravenous (IV) needle put in their skin to give them medicine or fluids, but may have veins that are very hard to see or feel. The mechanism of this observed effect is not entirely clear. The purpose of this study is to use an ultrasound to directly measure whether there is an actual change size of veins or change in blood flow in healthy adult volunteers when you give them 50% nitrous oxide, and see whether or not this change in size, or change in flow, is what causes the changes in visibility or palpability of the vein.
The study involves documenting the effects of inhaled nitric oxide upon ventricular-arterial coupling in patients with congenital heart disease and passive pulmonary blood flow. Consenting patients undergoing a clinically-indicated cardiac catheterization will be given inhaled nitric oxide for 10 minutes while intraventricular pressure-volume analysis will be make via conduction catheters.
The aim of the study is to facilitate radial artery access for cardiac catheterization. The investigators hypothesize that topical nitroglycerin and lidocaine will reduce radial artery spasm. Patients undergoing cardiac catheterization via the radial artery will be randomized to topical nitroglycerin + lidocaine versus placebo.
Fabry's disease a genetic disorder (X-linked recessive) due to the absence of the enzyme alpha-galactosidase A. The disease is characterized by abnormal collections of glycolipids in cells (histiocytes) within blood vessel walls, tumors on the thighs, buttocks, and genitalia, decreased sweating, tingling sensations in the extremities, and cataracts. Patients with Fabry 's disease die from complications of the kidney, heart, or brain. The objective of this study is to test the belief that patients with Fabry's disease have a problem with blood vessels becoming larger. The walls of blood vessels contain muscles that when they relax the vessel becomes larger. This process is referred to as vasodilation. It is controlled by a substance released by cells in blood vessels called EDRF (endothelium-derived relaxing factor). Several drugs can affect vasodilation. Researchers believe some drugs may work by blocking the affect of EDRF. Researchers would like to test the effects of these drugs on the blood vessels of normal volunteers and patients with Fabry's disease.
The purpose of this project is to identify sex-related differences in the effect of hypoxia on sympathetic vascular transduction.
Aging and obesity are both risk factors for cardiovascular disease (CVD). One process that links both of these conditions to CVD is vascular dysfunction. Data from animal studies indicate that endoplasmic reticulum (ER) stress may play an important role in the development of endothelial dysfunction in aging and obesity. Therefore, the goal of this study is to investigate the relative contributions of aging and obesity on vascular dysfunction and ER stress. Additionally, this study will determine if taking an oral supplement for 8 weeks will improve vascular dysfunction and ER stress. Results from this study have the potential to identify a safe treatment option for improving vascular function in aging and obese populations.
The main purpose of this study is to evaluate the effects of an acute dose of dietary nitrate in the form of beetroot juice on skeletal muscle blood flow in response to dynamic knee extension exercise in healthy older adults. All subjects will receive active (rich in dietary nitrate) or placebo (devoid of nitrate) supplementation.
The purpose of this study is to examine hypoxic vasodilation and the role of beta-adrenergic receptors in younger premenopausal, perimenopausal, and older postmenopausal women.
Examining two strategies as potential adjuvant therapies for Duchenne muscular dystrophy (DMD); aerobic exercise training (to induce adaptations in skeletal muscle and improve cardiovascular health) and tadalafil, an FDA-approved vasodilator (to optimize blood flow and muscle perfusion which is impaired and often overlooked in DMD). Target: improved muscle function, vascular health, and DMD treatment.
The objectives of this clinical trial are to 1) determine the effect of the TP compared to placebo on blood flow and platelet aggregation, 2) to determine the effect of the TP on cardiovascular health compared to a placebo and 3) to assess the safety and tolerability of the TP in healthy adults.
This study has two phases: Phase 1 is to examine blood pressure, microvascular function, and sympathetic nerve activity in mid-life adult binge drinkers vs. alcohol abstainers/moderate drinkers. Phase 2 is to examine the effect of 8-week aerobic exercise training on blood pressure, microvascular function, and sympathetic nerve activity in mid-life adult binge drinkers
The overall goal of this project is to better understand the effect of intermittent hypoxia (IH) on sympathetic neuronal discharge patterns in humans, as well as mechanisms that mediate persistent sympathoexcitation with IH.
Patients with sleep apnea are at increased risk of developing cardiovascular disease - with women at potentially greater risk than men. Contributing mechanisms are not well understood, but may be related to how women respond to low oxygen and, given over 70% of patients with sleep apnea are obese, the impact of obesity. This project seeks to increase our understanding of mechanisms that may contribute to sex differences in the cardiovascular response to low oxygen with the hope that this knowledge will improve the efficacy of current therapies and support the discovery of novel therapeutics.
The purpose of this study is to identify the impact of estradiol (E2) on the mechanisms that regulate vascular endothelial function in peri-menopausal (PERI) women. This study is the first step in understanding factors contributing to endothelial dysfunction in women with advancing reproductive age and in response to E2 administration.
The overall goal of this study is to address fundamental questions regarding how the molecule acetylcholine interacts with the sympathetic nervous system to regulate blood flow and oxygen delivery to working skeletal muscle in young and older adults. With advancing age, blood vessels supplying active muscle lose their ability to override sympathetic constriction, which limits delivery of oxygen and results in fatigue. Findings from these studies will serve as the foundation for new strategies to improve regional blood flow regulation in older adults and clinical populations, which will increase quality of life and help to preserve functional independence.
The goal of this study is to examine possible mechanisms of impaired vasodilaton in obese and Black/African American men and women as possible links to the elevated prevalence of cardiovascular dysfunction and disease. The main targets in this study are sources of oxidative stress.
Subjects with a known diagnosis of peripheral artery disease as measured by an abnormal ankle brachial index (\<.9 or \>1.1) will undergo a single 5 min exposure of 670 nm light, 1 cm above the gastrocnemius muscle. Blood flow will be measured by infusion of ultrasound contrast and subsequent acquisition of ultrasound images. 2 blood samples will be collected for measurement of nitric oxide metabolites.
Sleep is now recognized as important for disease prevention. Too little or too much sleep contributes to cardiovascular disease. Leading health organizations recommend adults sleep 7-9 hours per night for optimal health. This recommendation is based on research that finds reductions in sleep duration elevate blood pressure and impair vasodilation of blood vessels. One question raised in a recent NIH Workshop report (PMID:36448463) is whether stable sleep patterns, irrespective of a person's sleep duration, could mitigate the adverse effects of insufficient sleep on vascular function. This project will address this question in midlife adults using a randomized, crossover designed study.
The goal of this clinical trial is to see how small blood vessels respond to the stress of high intensity exercise, and if a safe and simple intervention called ischemic conditioning can protect blood vessels from the stress of exercise. Participants will come in for 3 study visits and get home-based ischemic conditioning. At Study Visit 1, participants will be assessed for their frailty and physical function. Afterwards, they will perform an exercise test. At Study Visit 2, patients will undergo 2 microvascular assessments, perform a high-intensity exercise, then undergo the same 2 microvascular assessments again. Participants will be given a handheld sphygmomanometer and a blood pressure cuff to take home. Depending on which group the participants get randomized into, participants will place the blood pressure cuff around their non-dominant upper arm and inflate to either a low or high pressure for 2 weeks at home. Participants will repeat the same steps in Study Visit 2 for Study Visit 3. In addition, participants will also be assessed for their frailty and physical function.