30 Clinical Trials for Various Conditions
The proposed research is a pilot study assessing kidney oxidative metabolism and insulin sensitivity after a 2-year weight loss intervention in those with autosomal dominant polycystic kidney disease who are overweight or obese.
A randomized,double-blind, active controlled,15 week study to evaluate the effects of nebivolol and valsartan alone and in combination on 24-hour ambulatory cardiac work and variability of heart rate-mean central systolic pressure product.
High-intensity interval training (HIIT) is an effective tool to improve cardiovascular fitness and maximal anaerobic power. Different methods of HIIT have been studied but the effect of a maximal effort cycling and very short exercise time (i.e., 4-s) with short recovery time (15-30 s) and a high number of repetitions (i.e., 30 bouts) is unknown.
Autosomal dominant polycystic kidney disease (ADPKD) is the most common monogenic cause of end-stage kidney disease (ESKD). The disorder is characterized by development and continued growth of multiple cysts requiring renal replacement therapy in 50% of patients by age 60 years. However, ADPKD is also a complex metabolic disorder defined by insulin resistance (IR) and mitochondrial dysfunction which may be causally related to cyst expansion, kidney function decline and contribute to reduced life expectancy. Renal hypoxia, stemming from a potential metabolic mismatch between increased renal energy expenditure and impaired substrate utilization, is proposed as a novel unifying early pathway in the development and expansion of renal cysts in ADPKD. By examining the interplay between renal O2 consumption and energy utilization in young adults with and without ADPKD, the investigators hope to identify novel therapeutic targets to impede development of cyst expansion in future trials. The investigators propose to address the specific aims in a cross-sectional study with 20 adults with ADPKD (50% female, ages 18-40 years). Comparative data will be provided from healthy adults from an ongoing study with similar study design and methods (CROCODILE Study: Control of Renal Oxygen Consumption, Mitochondrial Dysfunction, and Insulin Resistance). For this protocol, participants will complete a one day study visit at Children's Hospital Colorado. Patients will undergo a dual energy x-ray absorptiometry (DXA) to assess body composition, and a 11C-acetate positron emission tomography (PET/CT) scan to quantify renal O2 consumption. After the PET/CT, participants will undergo a hyperinsulinemic-euglycemic clamp while fasting to quantify insulin sensitivity. Glomerular Filtration Rate (GFR) and Effective Renal Plasma Flow (ERPF) will be measured by iohexol and PAH clearances during the hyperinsulinemic-euglycemic clamp.
Type 1 diabetes (T1D) is a complex metabolic disorder with many pathophysiological disturbances including insulin resistance (IR) and mitochondrial dysfunction which are causally related to the development of diabetic kidney disease (DKD) and which contribute to reduced life expectancy. Renal hypoxia, stemming from a potential metabolic mismatch between increased renal energy expenditure and impaired substrate utilization, is increasingly proposed as a unifying early pathway in the development of DKD. By examining the interplay between factors responsible for increased renal adenosine triphosphate (ATP) consumption and decreased ATP generation in young adults with and without T1D, this study hopes to identify novel therapeutic targets to impede the development of DKD in future trials. The investigators propose to address the specific aims in a cross-sectional study with 30 adults with T1D and 20 controls without a diagnosis of diabetes. For this protocol, participants will complete a one day study visit at Children's Hospital Colorado. Patients will undergo a Dual-energy X-Ray Absorptiometry (DXA) scan to assess body composition, renal Magnetic Resonance Imaging (MRI) to quantify renal oxygenation and perfusion, and a Positron Emission Tomography/Computed Tomography (PET/CT) scan to quantify renal O2 consumption. After the PET and MRI, participants will undergo a hyperinsulinemic-euglycemic clamp to quantify insulin sensitivity. Glomerular Filtration Rate (GFR) and Effective Renal Plasma Flow (ERPF) will be measured by iohexol and PAH clearances during the hyperinsulinemic-euglycemic clamp. To further investigate the mechanisms of renal damage in T1D, two optional procedures are included in the study: 1) kidney biopsy procedure and 2) induction of induced pluripotent stem cells (iPSCs) to assess morphometrics and genetic expression of renal tissue.
The purpose of this study is to determine if enhanced endothelial arterial distensibility observed with heat therapy translates into improved cardiorespiratory fitness. The following aims are proposed: Aim 1: to determine if chronic heat therapy results in improvements in cardiovascular function. Aim 2: To examine potential mechanism(s) of action of heat therapy in cardiovascular function.
This is a non randomized study to determine the effects of Gentle Jogger(GJ), a passive jogging device on oxygen consumption in 2 postures supine and seated. Oxygen consumption measurements will be performed via indirect calorimetry in duplicate at rest ( supine and seated posture) , and repeated in duplicate during GJ (in supine and seated posture)
The measurement of how much oxygen a baby consumes provides important information about the health of the baby, and of how much energy they are consuming. Currently, there is no device which measures either oxygen consumption, or another variable that depends on oxygen consumption - resting energy expenditure - in neonates or infants. Our group has developed a new device which can attach to any ventilator and measures these two variables with accuracy in the preclinical setting, including in rodents as small as severely preterm infants. The purpose of this study is to compare measurements of oxygen consumption and energy expenditure in neonates using this device and comparing it with a gold standard which is rarely used, a Douglas bag method in which expired gas is collected and later analyzed.
This study is to evaluate whether thiamine can increase oxygen consumption and lower lactate in patients who initially survive an in-hospital cardiac arrest. Patients who are successfully resuscitated after an in-hospital cardiac arrest and who are on mechanical ventilation in the intensive care unit will be enrolled, and will get either thiamine or placebo. Their oxygen consumption and lactate will be measured at serial time points and compared between groups. The investigators' hypothesis is that thiamine will help restore the body's ability to metabolize oxygen normally (aerobic metabolism), leading to an increase in oxygen consumption and a decrease in lactate.
The purpose of the Oxy-CAHN study is to improve the monitoring capabilities of newborn infants recovering from congenital heart surgery. Currently, we utilize important but unsophisticated measures, such as vital signs and lactate measurements, to monitor these patients. Although they are useful in categorizing patients as well or unwell, these signs currently lack the power quantify a patient's risk for cardiac arrest. More to the point, they are mostly indirect measures of what we really are assessing, which is tissue oxygen delivery. Our group has significant expertise with devices which quantify the amount of oxygen that a baby consumes every minute. Historically, these values are more commonly used in combination with other measures to assess nutritional and metabolism status. In critically ill patients, however, the volume of oxygen consumed by a patient may be limited by the amount of oxygen their circulation delivers. This may represent a critical relationship, which has been previously described, but not exploited for the purpose of identifying patients with critically low oxygen delivery. The aims of this study are therefore (1) to demonstrate that oxygen consumption can be safely and precisely measured continuously in newborns undergoing one of two common congenital heart surgeries, (2) to determine whether postoperative circulatory failure is associated with a precedent change in oxygen consumption, and (3) to determine whether the addition of the oxygen-based measurements (including oxygen consumption and venous oxygen saturations) to standardly measured parameters will add power in predicting which patients will experience postoperative circulatory failure. If successful, this study may improve our capacity to non-invasively and continuously monitor patients following the highest risk congenital heart surgeries, and in the future,to create an algorithm which quantifies a patients risk for having a cardiac arrest. This may permit providers to intervene on these patients earlier, improving the morbidity and mortality associated with congenital heart disease.
Maximal consumption of oxygen (VO2max) during exercise is used in patients with chronic obstructive pulmonary disease (COPD) to stratify perioperative risk. However, the impact of supplemental oxygen to prevent hypoxemia during exercise on maximal oxygen consumption and other ventilatory parameters during maximal exercise in the resting normoxic Chronic Obstructive Pulmonary Disease population is poorly defined. The investigators performed a randomized controlled trial in patients with COPD who underwent cardiopulmonary exercise tests on room air and supplemental oxygen. The investigators compared maximal oxygen consumption and other ventilatory parameters in each individual subject under the two conditions.
The goal of this observational study is to find out if researchers can measure oxygen consumption in the body without having to draw blood from lines in arteries and central veins. Participants will undergo measurements of arterial blood oxygen saturation using both finger and neck pulse oximeters.
The overarching aim of this proposal is to examine the feasibility of the Q-NRG+ indirect calorimetry device and its agreement with (Vmax) Encore indirect calorimetry device in mechanically ventilated children. The overall hypothesis of this study is that the Q-NRG+ will provide minute-to-minute oxygen consumption (VO2) and carbon dioxide production (CO2) measurements that are in agreement with those obtained by the standard indirect calorimetry device currently used at our institution (Vmax Encore).
The primary aim of this study is to investigate the impact of incorporating shortened resistance bands (SRB) into leggings on cardiovascular responses and caloric expenditure during exercise in young, healthy women. This study will employ a randomized, controlled, and double-blind crossover design involving four types of exercise: walking, climbing, rowing, and cycling. Participants will perform each type of exercise for 10 minutes while wearing either SRB leggings or leggings without SRB, with sessions on separate days and about 3 days apart. The cardiovascular and metabolic responses will be measured during and after the exercise.
This study will evaluate the clinical efficacy and safety of udenafil, an orally administered, potent and selective inhibitor of PDE5, versus placebo for the treatment of adolescent who have had the Fontan procedure.
The goal of this study is to test the feasibility of guiding as-needed pharmacological rate control of atrial fibrillation (AF) by implantable cardiac monitors and to assess the impact of continuous beta-blocker therapy versus as-needed rate control on the following outcomes: (1) exercise capacity, (2) AF burden, (3) symptomatic heart failure, (4) biomarker assessment of cardiac filling pressures and cardio-metabolic health, and (5) quality of life in patients with atrial fibrillation and stage II or III heart failure with preserved ejection fraction.
The prevalence of obstructive sleep apnea (OSA) is high in the United States and is a major health concern. This disorder is linked to numerous heart, blood vessel and nervous system abnormalities, along with increased tiredness while performing exercise likely because of a reduced blood supply to skeletal muscles. The gold standard treatment of OSA with continuous positive airway pressure (CPAP) in many cases does not lead to significant improvements in health outcomes because the recommended number of hours of treatment per night is often not achieved. Thus, development of novel treatments to eliminate apnea and lessen the occurrence of associated health conditions is important. The investigators will address this mandate by determining if repeated exposure to mild intermittent hypoxia (MIH) reduces heart and blood vessel dysfunction and tiredness/ fatigue experienced while exercise performance. The investigators propose that exposure to MIH has a multipart effect. MIH directly targets heart and blood vessel associated conditions, while simultaneously increasing upper airway stability and improving sleep quality. These modifications may serve to directly decrease breathing episodes and may also serve to improve usage of CPAP. Independent of its effect, MIH may serve as an adjunctive therapy which provides another path to reducing heart and blood vessel abnormalities that might ultimately result in improvements in exercise capacity and reverse performance fatigue in individuals with OSA.
In a prospective, observational pilot study of patients scheduled for an atrial fibrillation (AF) ablation at the University of Vermont Medical Center the investigators will compare exercise capacity before and four months after AF ablation.
The purpose of this study is to find out if taking the drug Buspar will increase breathing capacity in individuals with spinal cord injuries.
Blood-flow restriction training (BFR) is a technique utilized to provide the benefits of high intensity exercise (strength, power, hypertrophy) when applied to exercise intensities that are insufficient to produce these benefits without BFR. The technique involves the application of an occlusive cuff (similar in design to a blood pressure cuff) over the limb of an individual that is set to occlude arterial blood flow at a given percentage during exercise. BFR has demonstrated increased strength and muscle hypertrophy compared to control interventions in various populations including: healthy subjects, athletes, post-surgery, clinical rehabilitation, and older adults. Most research on BFR has been conducted on single joint exercises and not exercises that exhibit more complex movements typically associated with daily activities. The early evidence of complex exercises combined with BFR suggests that strength and hypertrophy both improve, however more research needs to be conducted. The purpose of this project is to determine if four weeks of BFR training combined with approach rowing and deadlifts increases strength, power, aerobic capacity, and muscle size. These results will be compared to an isovolumetric control.
This is a randomized, double-blind, placebo-controlled trial to determine if administration of intravenous thiamine will lead to quicker resolution of acidosis in patients admitted to the hospital with diabetic ketoacidosis. The investigators will secondarily investigate whether thiamine improves cellular oxygen consumption, shortens intensive care unit (ICU) and hospital stay or decreases hospital resource utilization.
This study will evaluate the clinical efficacy and safety of udenafil, an orally administered, potent and selective inhibitor of PDE5, versus placebo for the treatment of adolescent subjects who have undergone the Fontan procedure.
The purpose of this study is to find out if spironolactone added to ambrisentan for Pulmonary Arterial Hypertension (PAH) will increase exercise capacity. We also want to find out if spironolactone and ambrisentan effect the cardiac output (amount of blood the heart pumps every minute), right ventricle function and quality of life.
To determine the pharmacokinetic profile and safety of udenafil in adolescents with Fontan physiology and to assess the short-term pharmacodynamic effect of udenafil on pharmacodynamic measures of exercise capacity, ventricular performance, and vascular function.
The objective of this study is to determine the effect of thiamine therapy on oxygen consumption (VO2) in critically-ill patients. We will evaluate this by measuring VO2 before and after thiamine or placebo administration in patients admitted to the ICU and requiring mechanical ventilation. A secondary aim is to evaluate the effect of thiamine vs. placebo on the metabolic profile of the patients.
The purpose of this study is to determine if nitrates in a food, in this case - beetroot juice (BRJ) - is efficacious in improving exercise tolerance and/or peak power in patients with heart failure. The investigators will also determine if BRJ improves blood pressure, exercise efficiency, vascular and muscle function, and whether blood levels of nitrates increase hourly for a total of 4 hours after BRJ ingestion. A secondary aim is to determine if BRJ-derived nitrates are still effective at 1, 2 and 4 weeks after starting treatment. A tertiary aim is to determine the variation in the 6 minute walk test. Subjects will answer a basic medical information sheet and undergo a 6-minute walk test. After at least a 48 hours rest, subjects will be asked to repeat the 6 minutes' walk. The investigators will (1) determine if BRJ (as compared to placebo) improves peak power output in heart failure patients and controls (at \~ 1½ to 2 hours after ingestion); (2) compare the changes in cardiac muscle (on average \~ 8-12 hours after) BRJ or placebo ingestion in patients who will be undergoing an left ventricle (LV) assist device placement for clinical purposes. (a cross-sectional study); (3) determine if BRJ decreases elevated pulmonary artery (PA) pressures or improves vascular and/or microvascular function (at \~ 1½ - 2 hours after ingestion) in patients who are already coming in for a PA catheter placement for clinical purposes; (4) compare the physiological changes after BRJ ingestion in non-heart failure control subjects with those of patients with heart failure. Endpoints measured at the same time points after ingestion. The investigators hypothesize (1) that patients with heart failure and controls will have improved exercise capacity and power at lower oxygen cost (and thereby greater efficiency) \~ 1½- 2 hours after ingesting beet juice (BRJ) than after ingesting placebo (beet juice without nitrates); (2) that patients with heart failure will have a greater physiologic response to BRJ than non-heart failure controls since the former have worse physiological function to start with; (3) that patients with high pulmonary artery pressures will have an improvement in the pressures after ingestion with BRJ; (4) that myocardial perfusion will be higher after BRJ ingestion than after placebo; (5) that cyclic guanosine monophosphate (cGMP) levels will be increased in left ventricle assist device (LVAD) samples after BRJ ingestion compared with placebo.
The objective of this study is to determine the effect of thiamine therapy on oxygen consumption in critically-ill patients. The investigators will evaluate this by measuring VO2 before and after thiamine administration in patients admitted to the ICU and requiring mechanical ventilation.
The investigators propose a pilot randomized controlled trial to determine the safety and potential benefits of moderate intensity exercise in patients with hypertrophic cardiomyopathy. The investigators hypotheses are that exercise parameters derived from a baseline cardiopulmonary exercise test will target an appropriately safe level of exercise intensity that will not cause significant arrhythmias or exacerbate symptoms and that exercise training for 4 months will result in significant improvements in peak oxygen consumption (peak VO2) and quality of life, with neutral effects on the clinical characteristics.
During clinical anesthesia, it is astonishing that CO2 monitoring consists mainly of end-tidal PCO2 to confirm endotracheal intubation and to estimate ventilation, and O2 monitoring consists of a single PO2 measurement to detect a hypoxic gas mixture. Better understanding of how O2 and CO2 kinetics monitoring can define systems pathophysiology will greatly enhance safety in anesthesia by detecting critical events such as abrupt decrease in cardiac output (Q.T) by vena-caval compression during abdominal surgery, occurrence of CO2 pulmonary embolism during laparoscopy, rising tissue O2 consumption (V.O2) during light anesthesia, and onset of anaerobic metabolism (V.CO2 is disproportionately higher than V.O2).
The purposes of this study are: 1. To examine molecular and biochemical changes, associated with the relaxation response (RR) that can counteract the effects of stress in healthy adults. 2. To compare genomic, molecular and biochemical parameters between healthy adults with a long term meditative practice and those with no experience in meditation. Since stress is a factor in the development of many health conditions, a further understanding of the mechanisms of the RR should be developed. The project is designed to determine how the RR can improve the quality of life that has been adversely affected by stress.