300,000+ clinical trials. Find the right one.

229 active trials for Healthy Volunteers

Study of Human Non-Shivering Thermogenesis and Basal Metabolic Rate

Background: - Changes in how a person s body burns energy or calories can affect their weight over time. The lowest level of energy the body needs to function is called basal metabolic rate. In the cold, we burn extra energy, even before we start to shiver. This is called non-shivering thermogenesis and it occurs in different types of tissue such as muscle and fat. Researchers want to learn more about this type of energy burning and how it is regulated. They hope this will help treat obesity in the future. Objectives: Sub-study 1: to better understand how non-shivering thermogenesis works. Sub-study 2: to measure the effects of anti-obesity drugs on basal metabolic rate. Sub-study 3: to better understand the effects of mirabegron, a beta-3 adrenergic receptor agonist, on brown fat activity. Eligibility: - Healthy, lean adult males ages 18 to 35. Design: Participants will be screened with medical history, physical exam, blood test, and EKG. For sub-studies 1 and 2: Participants will receive one X-ray scan. Each day, all participants will: <TAB>- Have height and weight measured, and have urine collected. Spend 4 hours in a temperature-controlled room with furniture, toilet area, phone, and computer. They will wear small non-invasive devices to monitor activity, heart rate, temperature, and shivering. <TAB>- Walk for 30 minutes. -For sub-study 3: Participants will receive one DXA scan and up to 4 PET/CT scans and 4 MRIs Each stay, all participants will: <TAB>- Have height and weight measured, and have urine collected. Spend 6 hours in a temperature-controlled room with furniture, toilet area, phone, and computer. They will wear small non-invasive devices to monitor activity, heart rate, temperature, and shivering. Participants will be compensated for their time and participation at the end of the study

Start: February 2014
GSNOR Phenotyping/GSNO Challenge in Severe Asthma

Asthma is caused by or worsened by different things in different people. It is because of these differences that not all people with asthma respond the same to all treatments and medicines. If the investigators can better identify the changes in the airways or breathing pipes in patients with asthma, the investigators may be able to help patients make better choices about the medicines or treatments that are most likely to work best for each patient. This research study is about one specific factor that is known to affect asthma in some patients. It involves an increase in the activity of an enzyme that is in people's airways. An enzyme is something that helps a chemical reaction to occur. The enzyme the investigators are studying in this research study is called GSNOR (S-nitrosoglutathione reductase) , and when the activity of this enzyme is increased, the result is that there is less GSNO (S-nitrosoglutathione) . GSNO is a chemical that protects people's airways. The initials stand for S-nitrosoglutathione, (pronounced s-nahy-troh-soh-gloo-tuh-thahy-ohn), and it is naturally produced by the body. It has an important role in regulating respiratory function (breathing) and preventing inflammation (swelling) in the respiratory tract (throat, airways, and lungs). The amount of GSNO found in the body is controlled by the enzyme GSNOR (S-nitrosoglutathione reductase). GSNOR breaks down GSNO. Too much GSNOR leads to low levels of GSNO, and that can cause inflammation (swelling) and loss of airway function in some asthma patients. The only way to measure GSNOR levels currently is with a bronchoscopy procedure where a scope is inserted into the patient's airways, often under sedation. This research study is being done to test the accuracy of another type of test that can be done in the doctor's office, rather than in a procedure area. This non-invasive diagnostic test, called a GSNO Challenge test, may be able to identify which asthma patients have increased activity of the airway enzyme GSNOR. The investigators are also studying the phenotypes (observable traits) in asthma patients with increased levels of GSNOR. If this research study is successful, in the future (after this research study is done). The investigators may be able to offer a cost-effective and non-invasive way to identify patients who have higher GSNOR activity levels and offer personalized treatments. The GSNO Challenge test includes giving an investigational drug to breathe in (inhale). The investigational drug is GSNO. "Investigational" means the drug is not approved by any regulatory agencies including the Food and Drug Administration (FDA), and is still being tested for safety and effectiveness. The research is registered with the FDA, but again the GSNO treatment in this study (administered during the GSNO challenge testing) is not an approved treatment or diagnostic test for asthma.

Start: April 2019
Language and Brain Rhythms

For humans and other animals, predicting the timing of sensory events is essential for their daily behavior. Importantly, natural sensory stimulation (such as movements, music, or speech) can present temporal regularities allowing for temporal prediction of incoming sensory information. For instance, individuals can easily predict in time the next step of a walker, or the next beat of a song based on the rhythm. The phenomenon of temporal prediction has for now only been investigated experimentally in deterministic scenarios, i.e. when the duration between two sensory events is fixed, or when stimuli present a regular beat. The objective of this project is to understand how we process more natural, hence more complex forms of temporal regularities, and how individuals make inferences on the timing of sensory events based on past temporal statistics of sensory information. This is particularly important for speech processing, considering that speech is an acoustic signal that is known to possess some form of temporal regularity, and yet is not purely rhythmic nor does have a deterministic temporal structure. Temporal regularities are specific to each spoken language, and both native and non-native language listeners are known to use temporal acoustic cues during speech listening. This affects speech comprehension and has a strong impact during language learning. Hence, understanding the processing of temporal regularities in speech can help improve language abilities in first and second language learners. The project is composed of three experiments. The first behavioral experiment will investigate how auditory perception is affected by the temporal statistics of past sensory information using artificial stimuli. The second axis will investigate the neural mechanisms underlying auditory timing processing with electroencephalography (EEG). The last Magnetoencephalography (MEG) experiment will test the role of temporal statistics in an ecological setting, namely speech listening. The project will thus provide strong theoretical advances as it will give new insights on brain mechanisms for the processing of complex temporal information in audition and speech, and their role in language comprehension. It will also provide methodological advances. Specifically, the project will contribute to the development and validation of cutting-edge methods in MEG. Namely, it will aim at creating new tools to investigate the neural correlates of auditory and speech processing with an unprecedented temporal and spatial resolution.

Start: February 2021
Impact of Weekly Administration of Rifapentine and Isoniazid on Steady State Pharmacokinetics of Tenofovir Alafenamide in Healthy Volunteers (YODA)

Background: Human immunodeficiency virus (HIV) is treated with antiretroviral drugs. Many people with HIV also have the lung infection tuberculosis (TB). Most TB treatments are complicated. A simpler treatment of two TB drugs can be taken once a week. Researchers want to study how the HIV and TB drugs affect each other so people who take both can be treated safely. Objective: To study if rifapentine and isoniazid affect blood levels of the common antiretroviral TAF. Eligibility: Healthy adults ages 18-65 without HIV, TB, or hepatitis Design: Participants will fast before the screening visit. They will have a medical history, physical exam, and blood tests. Women may have a pregnancy test. During the study, participants must: Use effective birth control Not take most medicine Not drink alcohol At the baseline visit, participants will repeat screening tests and get TAF tablets. Participants will take TAF once a day for 31 days. They will keep track of doses and side effects. Over 32 days, participants will have 4 long visits and 4 short. At all visits, participants will: Fast the night before Get food Take that day s TAF Review their TAF supply Have pregnancy and blood tests Report side effects At 3 visits, participants will also take the 2 TB drugs and vitamin B6. At 3 long visits, participants will also have blood collected 8 times over 8 hours by plastic tube in an arm vein. Around Day 46, participants will fast and have blood and pregnancy tests. Two weeks later, they will get a call to see how they are feeling....

Start: June 2018