61 Clinical Trials for Various Conditions
Sleep at altitude is often poor. The purpose of this study is to evaluate the effects of a single dose of the opioid antagonist, naltrexone, on sleep quality and periodic breathing after rapid ascent to \~3800m altitude.
The aim of this randomized, crossover clinical trial is to determine the efficacy of a gut microbiota-targeted nutritional intervention containing a blend of fermentable fibers and polyphenols (FP) for mitigating increases in GI permeability, and decrements in immune function and neuropsychologic performance following rapid ascent to simulated high altitude. Fifteen healthy young adults will participate in each of three study phases that include a 14-day supplementation period in which participants will consume 1 of 2 supplement bars: placebo (PL, will be consumed during 2 phases) and FP supplementation (will be consumed during one phase only). During the final 2-d of each phase, participants will live in a hypobaric chamber under sea level or high altitude conditions.
The specific aim of this study is to evaluate whether acetazolamide 125mg daily is no worse than acetazolamide 250mg daily in decreasing the incidence of acute mountain sickness (AMS) in travelers to high altitude. The study population is hikers who are ascending at their own rate under their own power in a true hiking environment at the White Mountain Research Station, Owen Valley Lab (OVL) and Bancroft Station (BAR), Bancroft Peak, White Mountain, California
Low oxygen at altitude causes pauses in breathing during sleep, called central sleep apnea. Central sleep apnea causes repeated awakenings and poor sleep. Low oxygen itself and the induced oxidative stress can damage mental function which is likely worsened by poor sleep. Reduced mental function due to low oxygen can pose a serious danger to mountain climbers. However there is also mounting evidence that even in populations of people that live at high altitudes and are considered adapted, low oxygen contributes to reductions in learning and memory. Therefore there is a serious need for treatments which may improve sleep, control of breathing and mental function during low oxygen. Melatonin is a hormone produced in the brain during the night which regulates sleep patterns with strong antioxidant and anti-inflammatory properties. A study previously reported that melatonin taken 90 mins before bed at 4,300 m (14,200 ft) induced sleep earlier, reduced awakenings and improved mental performance the following day. However how melatonin caused these effects was not determined. Therefore this study aims to determine how melatonin effects control of breathing, sleep and mental performance during exposure to low oxygen.
The purpose of this study is to further understand the effects of altitude on the physiology of gas exchange in the pulmonary microcirculation in normal subjects and in people with chronic obstructive pulmonary disease (COPD) measured as the single-breath diffusing capacity for carbon monoxide (DLCOsb). The study will determine a mathematical formula to allow for altitude corrections in both study populations to be used clinically in pulmonary labs.
Ibuprofen is often taken by travelers to high altitude to treat the symptoms of acute mountain sickness such as headache and malaise. However, the blunting of inflammation by ibuprofen may slow the process of acclimatization to altitude, which relies on mediators of inflammation for adjustments in breathing. The study randomizes healthy subjects to receive ibuprofen or placebo and then ascend to altitude (12,500 feet). Blood cytokines and non-invasive measurements of blood and tissue oxygen levels will be made for 48 hours at altitude. The hypothesis being tested is that subjects receiving ibuprofen will have lower blood and tissue oxygen levels after 48 hours at altitude than will placebo subjects.
In low oxygen environments, such as altitude, some adults may become ill and suffer from acute mountain sickness. Further, all adults will find that exercising becomes much more difficult when compared with exercise at lower altitudes (e.g. sea-level). The purpose of this investigation is to study the effects of two drugs that may help people adjust to high-altitude quickly, prevent them from becoming ill and improve their exercise performance. The drugs are Methazolamide and Aminophylline.
This study will compare the ability of pulsed-dose oxygen from a concentrator to reverse altitude-induced hypoxemia compared to compressed gas from a standard oxygen cylinder.
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.
This study is to determine whether bosentan will alter exercise capacity after rapid ascent to high altitude. We hypothesize that bosentan administration will improve arterial oxygenation and exercise capacity.
To compare the effects of IV iron versus placebo (saline) injection on arterial oxygen saturation, submaximal exercise responses, and 2-mile treadmill time-trial performance during acute exposure to hypobaric hypoxia (430 mmHg, simulating \~4800m) assessed 1 and 14 days after treatment. Primary Hypothesis 1: IV iron treatment will improve arterial oxygen saturation at rest and during exercise in acute hypobaric hypoxia and this effect will persist for 2 weeks Primary Hypothesis 2) IV iron treatment will improve 2-mile treadmill time trial performance in acute hypobaric hypoxia and this effect will persist for 2 weeks
The goal of this study is to learn if the probiotic SLAB51 (Sivomixx800®) works to enhance acclimatization to high altitude in humans. The main questions it aims to answer are: Does SLAB51 improve oxygen saturation during high-altitude exposure? Researchers will compare SLAB51 to a placebo (a substance that contains no probiotic) to see if SLAB51 works to enhance high-altitude acclimatization. Participants will: Take SLAB51 or a placebo three times daily during two separate three-night acclimatization periods at high altitude, spaced at least six weeks apart. Complete baseline measurements at sea level. Visit the high-altitude Barcroft Station (3,801 m) at the University of California White Mountain Research Center for physiological measurements and assessments. Undergo assessments including oxygen saturation, ventilation, heart rate, blood pressure, sleep studies, cognitive assessments, exercise capacity, Acute Mountain Sickness scores, and provide blood, fecal, and urine samples for advanced analyses.
The purpose of the present study is to investigate the feasibility, accessibility, and potential clinical benefits of implementing a moderated online social media platform with therapeutic content, Altitudes, to parents, caregivers, and supporters of young people with psychosis across the state of North Carolina, including in Coordinated Specialty Care (CSC) programs, Specialized Treatment Early in Psychosis (STEP) programs, and other community services where caregivers or supporters of young persons experiencing psychosis receive care. The investigators will evaluate acceptability and feasibility with up to 50 caregivers and supporters over the course of 6 months. Acceptability and usability will be assessed with various acceptability measures with the Altitudes caregivers and supporters, and caregivers and supporters' engagement with the digital platform. The investigators will additionally evaluate the impact of the platform on caregiver and supporter's psychological status, well-being, and social support, as measured via self-report questionnaires.
Creatine supplementation has been shown to increase exercise performance at sea level. The goal of this study is to determine the effects of creatine supplementation on exercise performance at simulated altitude.
To understand alterations in glycogen and molecular regulation of skeletal muscle glucose uptake, glycogen synthesis, and muscle protein recovery when consuming CHO (glucose) or CHO+PRO (glucose + whey) post-exercise during unacclimatized high altitude exposure, randomized crossover double blinded studies will be conducted in the hypobaric/hypoxic chamber at USARIEM Table 1. Briefly, the study consists of a 2 day baseline period at SL followed by two, 3 day trial periods (with the 3rd day being a testing day) at HA. The baseline is separated from trial 1 for a least a day, and trial 1 \& 2 separated by at least 4 days. Volunteers will consume CHO (glucose) or CHO+PRO (glucose + whey) drinks post-exercise during unacclimatized high altitude exposure during the two trial periods. The order of the drinks will be randomized (using a random number generator such as randomizer.org) and kept by a study staff not directly involved in data collection to maintain blinding.
The primary purpose of this study is to evaluate the efficacy of sabirnetug infusions administered once every four weeks (Q4W) in slowing cognitive and functional decline as compared to placebo in participants with early Alzheimer's disease.
Apparent hypoxia-induced insulin insensitivity along with alterations in glucose kinetics suggests reduction in glucose uptake by the peripheral tissue is a primary factor contributing to reductions in exogenous glucose oxidation at HA. As such, the primary objective of this study is to determine the ability of an insulin sensitizer (Pioglitazone, PIO) to enhance exogenous glucose oxidation and metabolic clearance rate during metabolically-matched, steady-state exercise during acute HA exposure compared to placebo (PLA) in native lowlanders. Secondary objective of this study will be to assess the impact of PIO on markers of inflammation and iron status compared to PLA. This randomized crossover placebo control double blinded study will examine substrate oxidation and glucose kinetic responses to ingesting supplemental carbohydrate (glucose) during metabolically-matched, steady-state exercise with acute (\~5 h) exposure to HA (460 mmHg, or 4300m, barometric pressure similar to Pike's Peak) after receiving PIO (HA+PIO), or after receiving a matched placebo (HA+PLA). Eight healthy, recreationally active males between the ages of 18-39 yrs will be required to complete this study. Following a 4 day glycogen normalization period receiving PIO or PLA daily, volunteers will complete two 80-min trials, performing metabolically-matched, steady-state aerobic (same absolute workload corresponding to \~55 ± 5% of V̇O2peak at HA) exercise on a treadmill, and consuming 145 g of glucose (1.8 g/min); one trial with HA+PIO and the other with HA+PLA. A dual glucose tracer (13C-glucose oral ingestion and \[6,6-2H2\]-glucose primed, continuous infusion) technique and indirect calorimetry will be used to selectively analyze endogenous and exogenous glucose oxidation, as well as glucose rate of appearance (Ra), disappearance (Rd) and metabolic clearance rate (MCR). Serial blood samples will be collected during each trial to assess endocrine and circulating substrate responses to exercise, carbohydrate, and hypoxia with or without PIO. All trials will occur at the same time of day in the USARIEM hypobaric/hypoxic chamber and be separated by a minimum 10-d washout period. The primary risks associated with this study include those associated with acute hypobaric hypoxia, exercise, and blood sampling.
The objective of this study is to assess the acceptability and feasibility of Altitudes, a novel digital behavioral health and psychoeducational intervention for caregivers and supporters of individuals experiencing first episode psychosis. The investigators will evaluate acceptability and feasibility with up to 30 caregivers and supporters over the course of 6 months. Acceptability and usability will be assessed with various acceptability measures with the Altitudes caregivers and supporters, caregivers and supporters' engagement with the digital platform, and qualitative interviews with the Altitudes caregivers and supporters. The investigators will additional evaluate the impact of the platform on caregiver and supporter's psychological status, wellbeing, and social support, as measured via self-report questionnaires.
Dyspnea and exercise intolerance are well known to travelers who have experienced time at high elevations, greater than 2500 meters (8200 feet). As individuals ascend to higher elevations, oxygen saturations significantly decrease as the partial pressure of oxygen decreases. Additionally, many individuals develop subclinical cases of high altitude pulmonary edema (HAPE), which may worsen hypoxemia and decrease exercise performance. While dyspnea and exercise intolerance are usually self-limiting and improve with rest, some individuals experience severe symptoms that prevent safe evacuation to lower elevation. Individuals experiencing high altitude dyspnea, subclinical HAPE, or clinical HAPE will see improvements in symptoms and SpO2 when receiving supplemental oxygen, however this requires heavy and unwieldy tanks that make it difficult to carry across irregular terrain. Additionally, given the often-remote conditions where supplemental oxygen is needed, it is often difficult to replenish supplies. Other devices, such as the portable hyperbaric chamber (often referred to as Gamow bag), can temporarily improve dyspnea and oxygen saturation at high and extreme altitudes without the use of oxygen tanks. This device also carries some of the same disadvantages as supplemental oxygen, however, as the bag is also heavy and patients are not ambulatory while using the device. Similar to supplemental oxygen and the portable hyperbaric chamber, there is some evidence that CPAP may improve SpO2 and dyspnea at high and extreme altitudes. CPAP has already demonstrated significant efficacy in reducing symptoms of acute mountain sickness (AMS) when used in the field. At the time these small studies were conducted, CPAP therapy carried similar disadvantages in weight and portability. In recent years, however, CPAP devices have become increasingly lightweight and portable, with recent models weighing less than 1 kilogram (2.2 pounds). These devices are often powered by batteries, which themselves are light and easy to carry, and can be charged in the field using either a generator or foldable solar panels. These newer features of CPAP devices overcome some of the previous disadvantages that have limited its potential uses. CPAP devices can easily be carried across difficult terrain directly to individuals suffering from altitude-related symptoms, to be used as a rescue device until definitive care is available. Its portability not only allows for easy delivery to a patient, but also may allow for a patient to experience enough symptom relief to walk themselves down to lower elevation, greatly improving speed and resource utilization involved in high altitude rescues. In previous studies, CPAP devices have been found to be effective and safe to use in high and extreme altitude locations. While a few pilot studies have assessed CPAP's utility in treating dyspnea and SpO2 at altitude, these studies were done at rest. While one study showed improved symptoms and SpO2 in normobaric and hypobaric hypoxia, the study was limited by its lack of real-world condition, and its authors suggested further study in field and extreme environmental conditions. Additional investigation is needed to determine whether or not CPAP is an effective tool in the field to improve SpO2, dyspnea, and exercise tolerance in individuals traveling at high elevations.
Investigating the utility of prophylactic treatment with iron sucrose and/or erythropoietin on the prevention of acute mountain sickness in fit, young, healthy individuals.
This phase I/II trial tests the safety, side effects, and best dose of venetoclax, daratumumab, and dexamethasone for the treatment of systemic light-chain amyloidosis in patients with a deoxyribonucleic acid (DNA) abnormality called a translocation involving chromosomes 11 and 14, or "t(11;14)". Venetoclax works by attaching to a protein called Bcl-2, in order to kill cancer cells. Daratumumab works by binding to a target on the surface of cancer cells called Cluster of differentiation 38 (CD38). When daratumumab binds to CD38, it enables the immune system to find the cancer cell and kill it. Dexamethasone is a type of drug called a corticosteroid. A corticosteroid is a drug made of artificial steroid hormones, that are used to treat symptoms such as inflammation (swelling and irritation to a part of the body). The combination of these medications may more effectively treat patients with systemic light-chain amyloidosis and t(11;14).
The aim of this randomized, double-blind study is to determine whether erythropoietin (Procrit) and acetazolamide: 1) mitigates altitude-induced decrements in performance at moderate altitude (3,000 m) and 2) mitigates altitude-induced decrements in performance and reduce acute mountain sickness during prolonged exposure to high altitude (4,300 m; 15 days). Volunteers will complete 5 study phases: Phase 1) sea level baseline testing and a moderate altitude exposure; Phase 2) 4 week study intervention - randomly assigned to receive erythropoietin or placebo); Phase 3) 3 1/2 days of acetazolamide and a moderate altitude exposure; Phase 4) high altitude acclimatization - 15 days at Pikes Peak; and Phase 5) two week deacclimatization. Test battery include VO2peak, 3.2 km treadmill time trial, measures of gas exchange and ventilation during rest and exercise, and blood collection.
This is a randomized, placebo-controlled, crossover study of Trans Sodium Crocetinate (TSC) in healthy volunteers, age 18-40 (inclusive), exercising at altitude. The primary objective is to determine the effect of (TSC) on partial pressure of oxygen (PaO2) and maximal oxygen consumption (VO2 max); the secondary objective is to assess the effect of TSC on oxygen saturation (SpO2).
Near-infrared spectroscopy (NIRS), is a technology that can provide continuous, non-invasive monitoring of oxygenation in tissue. The objective of this study is to obtain the cerebral regional oxygen saturation (cRSO2) in a preterm population that is born at altitude to determine if the range of "normal" values is different than those obtained at sea level.
The primary objective is to evaluate the efficacy of continuous positive pressure on resolution of high-altitude pulmonary edema vs high flow oxygen. The secondary objective is to derive an incidence of high-altitude pulmonary edema based on the elevation and timing from which the subject arrives. Additionally, in a convenience sample of the base study population, an ultrasound evaluation for the presence of B lines in the lungs will be conducted after 2 hours.
Recent studies have reported that oxidation of exogenous carbohydrate is reduced under acute hypobaric hypoxic (high altitude; HA) conditions compared to normoxia (sea level; SL) in native lowlanders. However, the mechanisms by which HA suppresses exogenous carbohydrate oxidation are not known. This study will seek to confirm that acute HA exposure decreases exogenous carbohydrate oxidation during steady-state aerobic exercise compared to SL, and explore if the mechanism inhibiting plasma glucose uptake is insulin dependent or independent.
The investigators expect to find that different intensity and altitude exposure levels will show what kind of intermittent exposure protocol is more beneficial to athletes and healthy individuals that experience acute exposure to altitude during exercise. This may furthermore be related to acute altitude exposure for recreational exercise use as well.
Low oxygen at altitude causes pauses in breathing during sleep, called central sleep apnea. Central sleep apnea causes repeated awakenings and poor sleep. Low oxygen itself and the induced oxidative stress can damage mental function which is likely worsened by poor sleep. Reduced mental function due to low oxygen can pose a serious danger to mountain climbers. However there is also mounting evidence that even in populations of people that live at high altitudes and are considered adapted, low oxygen contributes to reductions in learning and memory. Therefore there is a serious need for treatments which may improve sleep, control of breathing and mental function during low oxygen.Therefore this study aims to determine how melatonin effects control of breathing, sleep and mental performance during exposure to low oxygen.
Individuals traveling to altitudes above 8,000 feet may suffer from impaired exercise and cognitive performance, and acute mountain sickness (AMS). Decreased barometric pressure, which leads to low blood oxygen levels, is the primary cause of these disorders. Symptoms of AMS are characterized by headache, nausea, vomiting, dizziness, fatigue, and difficulty sleeping. The goal of this research is to identify whether Respiratory Muscle Training will improve physical and cognitive performance, and reduce the symptoms of AMS, at simulated high altitude.
The goals of the present study are to evaluate whether the most common, and effective, treatment for acute mountain sickness (AMS), acetazolamide (AZ), has a negative, positive, or no influence on exercise performance, cognitive performance, or manual dexterity in young healthy subjects during simulated altitude exposure. AMS represents a serious challenge to the health and performance of the Warfighter who may need to rapidly deploy to high altitude. However, there have been concerns that AZ might alter or impair endurance exercise performance, and possibly fine motor skills. These would represent major limitations to the use of this drug in a Warfighter who has a specific timeframe in which to accomplish mission tasks. In the present project, we will use exposure to simulated altitude in the USARIEM hypobaric chamber to quantify the impact, if any, of AZ on endurance exercise performance following rapid ascent to 3500 meters (m) in unacclimatized lowlander volunteers. The study will be conducted using a randomized, single-blind, placebo-controlled crossover study design. Ten male and female volunteers will complete one orientation day, one VO2peak day, three days of familiarization testing at sea level (SL), then two rounds of experimental testing. Each round of experimental testing consists of six days including four days to establish baseline euhydration, followed by a 30 hour (hr) exposure to 3500 m. Volunteers will have a two week break between experimental testing rounds for washout of any effects of altitude acclimation. During one experimental round, volunteers will take two doses of AZ each day (Phase 1: 250 mg/dose,500 mg/day, Phase 2: 125 mg/dose, 250 mg/day) starting 48 hr prior to their altitude exposure and continuing for the 30 hr stay at high altitude. During the other experimental condition, volunteers will be given a placebo at the same time points as the doses of AZ. Prior to altitude exposure, AMS will be evaluated and volunteers will then ascend to a simulated altitude of 3500 m, where they will remain for 30 hr. Volunteers will rest at altitude for an hr, after which they will complete an AMS questionnaire, resting ventilation measurements, provide a blood sample and complete cognitive and finger dexterity testing. Subjects will then perform 15 minutes (min) of steady state (SS) treadmill exercise at 40-45% of SL VO2peak and a 2 mile treadmill time trial (TT). Volunteers will stay overnight in the hypobaric chamber with research staff supervision. The following morning, metabolic and blood measurements will again be completed, after which volunteers will perform the exercise testing for a second time. Cognitive and finger dexterity testing will be performed before volunteers return to sea level (i.e., "descend" from the simulated altitude). The results of the proposed study will, for the first time, provide quantitative evidence regarding whether AZ treatment impairs endurance exercise performance in the context of a Warfighter-relevant endurance exercise task.