28 Clinical Trials for Various Conditions
The purpose of this project is to determine if hyperinsulinemia attenuates sympathetic nervous system-mediated vasoconstriction in the human leg.
Cardiovascular disease (CVD) afflicts nearly one-third of the adult population with all races and ethnicities represented in CVD prevalence. Unfortunately, a disparity exists such that the black population (BL) is disproportionately affected compared to other groups, including the white population (WH). While the underlying cause of this disparity is multifactorial, vascular dysfunction (i.e., impaired vasodilation and/or augmented vasoconstriction) is a key contributor. As has been previously observed, BL exhibit a heightened vasoconstrictor response to both pharmacological (e.g., alpha-adrenergic receptor agonists) and environmental (e.g., cold pressor test) stimuli compared to their WH counterparts. Additionally, reactive oxygen species (ROS) and the subsequent reduction in nitric oxide (NO) bioavailability may partially mediate this response. Our laboratory has recently observed (UTA IRB 2016-0268) that the small blood vessels in the skin (cutaneous microvasculature) in BL, but otherwise healthy individuals, produce an impaired blood flow response to local heating when compared to age-, body mass index (BMI)-, and gender-matched WH. However, pre-treatment of the cutaneous microvasculature with various antioxidants abolishes this skin blood flow difference. These antioxidant drugs inhibit possible sources of ROS, which, as mentioned, maybe mediating the heightened vasoconstrictor response in BL. However, this has not been investigated in this population and thus remains unknown. Therefore, the purpose of this study proposal is to test the following hypotheses: 1) BL will have a greater reduction in cutaneous blood flow in response to local administration of Norepinephrine (alpha1-adrenergic and alpha 2-adrenergic receptor agonist) relative to WH. 2) This greater reduction in the BL population will be related to elevated oxidative stress and subsequent reduction in bioavailability of the potent vasodilator Nitric oxide.
The goal of this study is to examine possible mechanisms of heightened vasoconstriction in 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.
The goal of the study is to examine the possible mechanisms of impaired cutaneous microvascular function through local heating along with administration of vasoconstrictors.
The objective of this study is to determine if single dose administration of inhaled iloprost will reduce pulmonary artery pressure, reduce hypoxic pulmonary vasoconstriction and improve arterial oxygenation at rest and during exercise at high altitude.
To compare pharmacodynamic vasoconstriction response profile of Clocortolone Pivalate 0.1% Cream and Cloderm® (Clocortolone Pivalate) 0.1% Cream in normal skin of healthy male and female adults
The purpose of this study is to determine if the events leading to smoking-associated centrilobular and paraseptal emphysema are caused by a failure of the lungs' inherent mechanisms to block hypoxic pulmonary vasoconstriction (HPV) in areas of smoking-induced inflammation.
The purpose of this study is to better understand the contribution of sympathetic vasoconstriction to impaired insulin-mediated vasodilation and subsequently insulin-mediated glucose uptake. The investigators will test the hypothesis that removal of sympathetic vasoconstriction can result in improvement in insulin-mediated vasodilation and subsequently sensitivity to insulin-mediated glucose uptake.
The purpose of this study is to understand how dipeptidyl peptidase IV (DPP4) inhibition in diabetics affects hemodynamic parameters and sympathetic activation in the setting of increasing concentrations of neuropeptide Y, an endogenous peptide. The central hypothesis is that DPP4 inhibition decreases degradation of neuropeptide Y, resulting in increased vasoconstriction and sympathetic activation.
The investigators study will determine how often blood flow regulation abnormalities and abnormalities of sympathetic regulation produced by nitric oxide, angiotensin-II, and oxidative stress occur in POTS and the mechanism(s) of POTS in individual patients. Specific causes for POTS may vary from patient to patient. Patients will be compared to healthy control subjects. There is a treatment arm with a medication (losartan) that reduces the binding of angiotensin and increases NO. If the investigators know the specific biochemical mechanism the investigators may be able to offer further specific treatments to specific patients.
The purpose of this study is to evaluate the effects of Dexmedetomidine when used during thoracic surgery. The primary outcome will be changes in oxygenation as measured the PaO2 during one lung ventilation.
The objective of this study is to determine if single dose administration of inhaled iloprost will reduce pulmonary artery pressure, reduce hypoxic pulmonary vasoconstriction and improve arterial oxygenation at rest and during exercise at high altitude.
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.
This is a randomized clinical trial of short-acting nimodipine versus twice daily extended release verapamil to treat patients presenting with Reversible Cerebral Vasoconstriction Syndrome (RCVS).
The purpose of this study is to improve the scientific understanding of the cardiovascular actions of cocaine, in particular the ability of cocaine to increase blood pressure.
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.
Obstetric hemorrhage is one of the leading causes of maternal death worldwide. One of the challenges in management of hemorrhage is that young, healthy women compensate for blood loss via peripheral vasoconstriction, so they maintain their blood pressure and heart rate at normal levels even after experiencing significant blood loss. By the time vital sign abnormalities appear, interventions must be performed extremely rapidly to avoid organ damage and maternal death. Clinical methods of estimating blood loss in real time, such as visual estimation, are notoriously unreliable, and changes in laboratory testing such as hemoglobin levels lag hours behind actual blood loss. A tool which can detect and quantify blood loss in real time, before vital sign changes occur, has the potential to allow for earlier mobilization of resources and intervention in these cases, thus saving lives. This device is meant to detect changes in skin blood flow which reflect vasoconstriction. The investigators believe that this device, therefore, has the potential to be able to detect and quantify blood loss in real-time. However, as this novel device has never been used for this purpose, before undertaking a large clinical trial, the investigators feel it is necessary to perform a pilot study to assess the feasibility and tolerability of this device. The investigators plan to test this by asking 50 patients undergoing planned cesarean section to wear the device during their surgery. The device will collect skin perfusion measurements during the surgery, which will not be available to the operating team. The patients will also be asked to complete a survey regarding their experience wearing the device. The investigators will use this information to ensure that the device is transmitting interpretable data, that patients feel the device is tolerable during surgery, and to ensure that the device can be used in the operating room without any unforeseen logistical challenges which would need to be addressed in planning a larger trial. The investigators will perform a preliminary comparison of sensor readings to laboratory findings, to assist in planning a larger trial.
The goal of this study is to examine possible mechanisms of heightened vasoconstriction in 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
This is the second part of a research study in order to determine if using a specialized pulse oximetry probe with external heat pack will help obtain oxygen saturation (SaO2) and heart rate (HR) during monitoring for patients with peripheral vascular disease (PVD), vasoconstriction, and hypothermic extremities. The inability to obtain accurate SaO2 and pulse readings can lead to misdiagnosis, incorrect treatment, or procedures to be canceled. SaO2 and pulse readings are important to maintain patient stability during diagnostic testing, surgical procedures and monitoring while in critical care areas. Changes in SaO2 and pulse are important to monitor in order to be able to compensate for any decrease in patient oxygen saturations during hemodynamic monitoring. The primary aim of this study is to determine if using a specialized pulse oximetry probe with external heat pack will improve oxygenation readings in order to obtain SaO2 and pulse readings in patients with PVD, vasoconstriction, and hypothermic extremities as compared to readings obtained from an arterial blood gas. The hypothesis is using a specialized pulse oximetry probe with external heat pack will help obtain more accurate pulse oximetry readings consistent with values obtained with an arterial blood gas.
The purpose of this study is to create a state-wide biorepository and resource center for cerebrovascular diseases in Florida, which will include collecting medical history information and blood from subjects affected by cerebrovascular disease. The information and blood samples collected may be used in future research for the study of cerebrovascular disease and to learn about, prevent or treat other health problems.
Individuals who operate in cold weather are at risk of developing cold injuries, for example, frostbite. They also often experience a loss of hand function and joint mobility due to a decrease in skin temperature and blood flow. In addition, the risk of getting a cold injury is higher in the Black population compared to other racial and ethnic groups. Increases in oxidant compounds can cause the blood vessels in the skin to narrow and decrease skin temperature in the cold. However, it is unknown whether the higher risk of cold injury in Black individuals is because of a greater amount of oxidant compounds in the blood vessels. The purpose of this research is to see if an antioxidant supplement called MitoQ can help to improve skin temperature and blood flow in the cold and if the improvement is greater in Black individuals.
Double-blind, sham- and placebo-controlled randomized study of effects of freshly-generated diluted diesel exhaust inhalation on vascular function. To examine role of adrenergic system a trial of alpha-blocker terazosin is also used. Each participant completes four study sessions, separated by at least three weeks: 1) Diesel exhaust inhalation (DE, controlled at 300 micrograms/cubic meter for two hours) and terazosin (2 mg prior to inhalation exposure); 2) DE plus placebo (matched for terazosin); 3) filtered air plus terazosin; and 4) filter air plus placebo. The investigators assess outcomes of blood pressure, forearm brachial artery ultrasound, and plasma measures of endothelial activation. The investigators hypothesize that DE exposure will be associated with increased blood pressure, decreased brachial artery diameter, and increased circulating endothelins, and that these effects will be attenuated by terazosin administration.
The purpose of this study is to compare the vasoconstriction response profile and bioequivalence between one innovator lot of Ultravate® 0.05% ointment and one test/generic lot of Halobetasol propionate 0.05% ointment (Alpharma USPD, Inc.).
The purpose of this study is to determine the duration of application of halobetasol propionate 0.05% ointment to be used in a definitive study of bioequivalence of to formulations of this ointment. Part A: To validate vasoconstrictor assay precision. Part B: To evaluate the dose response vasoconstriction profile of Ultravate® 0.05% ointment at different dose durations over a short period of time (0.17 - 4 hrs).
To compare the relative vasoconstrictive effects of two topical clobetasol propionate 0.05% lotions in asymptomatic subjects.
To determine the dose-response relationship for Clobex TM (clobetasol propionate) Lotion, 0.05%. This information will be used to estimate the ED50, D1, D2 parameters for use in a full bioequivalence study.
Previous studies have shown that insulin may stimulate the release of endothelin (ET) from endothelial cells. This mechanism may contribute to the adverse vascular effects determined by chronic hyperinsulinemia. The aim of this study will be to evaluate the effect of local hyperinsulinemia on ET activity in the forearm circulation. To this purpose, we will assess the forearm blood flow response to ET receptor antagonism in control conditions and during intraarterial infusion of insulin. We will also measure changes in plasma ET-1 levels in response to the different pharmacological stimuli.