Clinical Research Directory
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401 clinical studies listed.
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Tundra lists 401 Healthy Volunteers clinical trials. Each listing includes eligibility criteria, study locations, and direct links to research sites in the Tundra directory.
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NCT07599761
A Phase 1 Study to Assess the Effect of Itraconazole on ABBV-722 in Healthy Adult Participants
The objective of this study is to assess the effect of repeated doses of itraconazole on the single dose pharmacokinetics (PK) of ABBV-722.
Gender: All
Ages: 18 Years - 65 Years
Updated: 2026-08-28
1 state
NCT00001309
The Body's Affect on Vitamin C
Pharmacokinetics is the term used for how the body affects a drug once it is taken. Vitamin C, also known as ascorbic acid, is an essential water soluble vitamin. Meaning, the body does not make Vitamin C it must be taken in through the diet. In this study researchers will attempt to determine how the amount of water consumed affects the level of vitamin C in the blood (specifically the plasma component of the blood). In this study researchers will take 13 subjects and place them on a Vitamin C restricted diet. Vitamin C levels will be measured twice a week on an outpatient basis until all subjects reach a desired low level of Vitamin C (12-15 micromolar plasma ascorbic acid concentration). Subjects will then be admitted and undergo 24 hour blood and urine collection. Following the collection of samples, subjects will then begin to receive Vitamin C orally (by mouth) and intravenously (injected into the vein). The dosage of Vitamin C will gradually increase from 30 mg-2500 mg divided into two daily doses. Blood and urine samples will be collected each time the dose is increased. The study will take approximately 18 weeks after which the subjects will be discharged in healthy condition....
Gender: All
Ages: 18 Years - 35 Years
Updated: 2026-08-28
1 state
NCT00114647
Apheresis to Obtain Plasma or White Blood Cells for Laboratory Studies
This study will collect blood plasma and white blood cells from individuals using a procedure called apheresis. Apheresis is a method of collecting larger quantities of certain blood components that can safely be collected through a simple blood draw. The blood components will be used in laboratory research studies. Patients 18 years of age and older who are currently enrolled in a NIH clinical research protocol may participate in this study. Relatives of patients and normal healthy volunteers will also be enrolled. Individuals will undergo one of the following two apheresis procedures: * Automated pheresis Blood is drawn through a needle placed in an arm vein and circulated through a cell separator machine. The plasma (liquid part of the blood) and white cells are extracted, and the red cells are re-infused into the donor through the same needle or a needle in the other arm. An anticoagulant (medication to prevent blood from clotting) is usually added to the blood while in the machine to prevent it from clotting during processing. * Manual pheresis One unit (1 pint) of blood is drawn through a needle placed in an arm vein, similar to donating a pint of whole blood. The red blood cells, with or without plasma, are separated from the rest of the blood and returned to the donor through the same needle. Manual pheresis will be done only when a person s estimated total blood volume or red cell count is too low to safely permit removal of blood through a pheresis machine. An adult small in size or markedly anemic, for example, may fall into this category. Some of the blood collected through apheresis may be stored for future studies of HIV disease and immune function and for HLA testing, a genetic test of markers of the immune system. Some of the blood may be used to screen for different types of viral liver infections, such as hepatitis A, B, C, D, E, F, or G. ...
Gender: All
Ages: 18 Years - 100 Years
Updated: 2026-08-28
1 state
NCT07504601
Investigating the Analgesic Potential of (2R,6R)-HNK in Acute Pain in Healthy Volunteers
Background: Opioid drugs are often prescribed for acute and chronic pain. But these drugs are addictive, and they lead to more than 14,000 overdose deaths in the United States each year. Researchers want to find new drugs that relieve pain but are not addictive. This study will test whether a single dose of an experimental drug called (2R,6R)-hydroxynorketamine (HNK) can help reduce short term pain in healthy adults. HNK is related to ketamine. Studies suggest HNK might be as effective as ketamine at reducing pain but that it might have fewer side effects. In this study we will test how HNK affects pain and emotion. The results of this study may help us understand whether HNK has pain relieving effects and how it works in the brain, which could inform future pain treatments. Objective: To test the study drug \[(2R,6R)-hydroxynorketamine (HNK)\] for treating acute pain in healthy people. Eligibility: Healthy people aged 18 to 60 years. Design; Up to 92 healthy volunteers between 18 and 60 years old without chronic pain or psychiatric conditions will participate in the study. The study will take place at the NIH Clinical Center in Bethesda, Maryland. Each participant s involvement will last up to two months. The overall study is expected to last about three years (36 months). The study has 2 parts. In part 1, participants will have up to 2 clinic visits. They will be screened and have blood draws to make sure they're eligible for the study. They will complete sensory testing and have MRI brain scans. Sensory testing involves feeling and rating painful and non-painful sensations. These may include hot or cold temperatures, pinches or squeezes, and being touched with brushes or pinpricks. Eligible participants will have an imaging scan that shows brain activity: During the scan, they will rate heat, hear pleasant or unpleasant sounds, and view unpleasant or pleasant pictures. After completing part 1, eligible participants will be invited to part 2, which includes overnight stays at NIH. In part 2, participants will be assigned to either a treatment group or a no-treatment group. The treatment group will have 2 overnight visits of 2 nights each. The visits will be 1 to 3 weeks apart. For one of the visits, treatment group participants will receive the study drug HNK. For the other visit, they will receive a placebo. A placebo looks just like the study drug but contains no medicine. HNK and placebo are given through a tube inserted into a vein in the arm. The sensory tests, blood draws, and MRI scans will be repeated at each visit. Participants will not be told whether they got the drug or placebo on each visit. The nontreatment group will have 1 overnight visit. They will not receive the drug or placebo. The sensory tests, blood draws, and MRI scans will be repeated. Participants cannot drink alcohol, use recreational drugs, or take certain other kinds of medicine or supplements during the study.
Gender: All
Ages: 18 Years - 60 Years
Updated: 2026-08-28
1 state
NCT02446262
Neural and Psychological Mechanisms of Pain Perception
Background: \- Painful stimuli cause changes in a network of brain regions called the "Pain Matrix." But most of these regions respond to many other stimuli, not just pain. Researchers want to understand how different factors influence pain. They want to test what happens when people expect different levels of pain and receive treatments that can modify pain. They want to see if these factors influence decisions about pain and how the body responds to it. They also want to compare pain with responses like taste and vision. Objectives: \- To better understand how pain and emotions are processed and influenced by psychological factors. Eligibility: \- Healthy volunteers ages 18-50. Design: * This study requires 1 to 2 clinic visits that last 1 to 3 hours. * Participants will be screened with medical history and physical exam. * Some participants will have one or more magnetic resonance imaging (MRI) scans of their brain. For MRI, participants will lie on a table that slides in and out of a cylinder. The scanner makes loud knocking noises. They will get earplugs. * Participants' heart activity will be recorded with electrocardiogram. Their pulse, sweating, and breathing will be monitored. * Some participants will take a taste test. Others may perform simple tasks. Others may receive pain in their arm, leg, or hand. The pain will come from heat or electric shocks. Others may judge pain using a topical pain-relieving cream. Some of these tests may be given during MRI. * Participants will fill out questionnaires. * The study will last 3 years.
Gender: All
Ages: 18 Years - 50 Years
Updated: 2026-08-28
1 state
NCT04936685
Study on an Investigational Quadrivalent Meningococcal Conjugate Vaccine (MenACYW Conjugate Vaccine) Administered as a 5- and/or 10-year Booster Doses in Children and Adolescents Vaccinated 5 or 10 Years Earlier as Toddlers
The purpose of the MEQ00073 study is to describe the immunogenicity and safety of a booster dose and persistence of a priming dose of MenACYW conjugate vaccine (MenQuadfi®) in adolescents who had been vaccinated approximately 10 years earlier as toddlers as part of the MET51 study and to describe the immunogenicity and safety of a second booster dose (as adolescents approximately 5 years after the first booster dose) and the persistence of a first booster dose of MenACYW in adolescents who had been primed with MenACYW conjugate vaccine as toddlers as part of the MET51 study and had received a first booster dose as children approximately 5 years after the priming dose.
Gender: All
Ages: 6 Years - 7 Years
Updated: 2026-08-28
2 states
NCT00001471
Tissue Biopsy and Imaging Studies in HIV-Infected Patients
This study will examine tissue from the tonsils, lymph nodes and large bowel of HIV-infected patients to investigate changes in viral load and certain white blood cells during treatment. Normal volunteers and HIV-infected patients 18 years of age or older may be eligible for this study. Candidates will be screened with a medical history, physical examination, blood and urine tests and possibly an electrocardiogram (EKG). Blood tests may include HLA typing, a genetic test of immune system markers. Participants may undergo the following procedures: * Blood tests (patients and volunteers) * Biopsies The frequency of biopsies for given patients may vary, depending on their specific therapy. Typically, biopsies are done at a single time, or for patients starting a new therapy, biopsies could be performed before starting therapy, during therapy and possibly after completion of therapy. * Tonsil biopsies (patients and volunteers) Volunteers will have one tonsil biopsy. Patients will have no more than six tonsil biopsies, with no more than three in a 10-day period. The biopsy is done by an ear, nose and throat specialist as an outpatient procedure. The tonsils are numbed with a local anesthetic, and one to four pieces of tissue are extracted. * Lymph node biopsies (patients only) Patients will have no more than four lymph node biopsies, performed no more frequently than once a month. The biopsy is done by a surgeon and may require a 2- to 3-day hospital stay. The skin above the lymph nodes is numbed with a local anesthetic, an incision is made and the tissue is removed. Alternatively, a needle biopsy may be done, in which a small amount of lymph tissue is withdrawn through a special needle injected into the site. * Intestinal biopsies (patients and volunteers) Volunteers will have one intestinal biopsy procedure. Patients may have up to six intestinal biopsy procedures, each separated by at least 10 days. This is done by a gastroenterologist as an outpatient procedure. A flexible tube (sigmoidoscope or colonoscope) with a light and special lens at the tip is inserted into the rectum and large bowel. Wire instruments passed through the tube are used to extract small tissue samples. * Bronchoalveolar lavage (BAL; patients and volunteers) Volunteers and patients will undergo bronchoscopy in which a flexible tube (bronchoscope) with a light and special lens at the tip is inserted through the nose or mouth into the lungs, and the lining of the lung is sampled by washing the airways with small amounts of saline. The procedure is performed by a pulmonologist or critical care specialist, usually as an outpatient.
Gender: All
Ages: 18 Years - 100 Years
Updated: 2026-08-28
1 state
NCT01237093
Developing Biomarkers of Dietary Intake
Background: \- Researchers who study health and nutrition are interested in developing more accurate methods of determining what people eat from day to day and how it affects their general health. In particular, better methods are needed to determine if people are accurately remembering what they ate. One possible method involves the use of biomarkers, or indicators in urine, blood, saliva, fat, and hair, which are related to the intake of a particular food in a consistent way. One set of biomarkers in blood samples and hair may be used to determine the relative amount of meat, fish, and soda (corn/sugar cane) in a person s diet. However, more research is needed to study the effectiveness of using these biomarkers to accurately track dietary intake. Objectives: \- To validate the use of biomarkers as representative of specific dietary intake patterns (meat/fish/soda). Eligibility: \- Healthy, nondiabetic men between 18 and 65 years of age. Design: * This study involves an initial screening visit and a 12-13 week inpatient dietary study period. * Participants will be screened with a medical history and physical examination, as well as blood and urine samples and a glucose tolerance test to exclude individuals who have diabetes. * After 3 days of a standard weight-maintaining diet, participants will have a glucose tolerance test and a body fat scan; provide hair, blood, and fat tissue samples; and complete questionnaires and performance tests. * Participants will spend one day in a metabolic chamber to measure their energy expenditure and general metabolism. * Participants will then be randomized into one of eight carefully designed diets for 12 weeks. The diets will differ in the amount of meat, fish, and soda, including one diet where none of the three biomarker-related foods will be permitted. Blood samples will be collected throughout the study diet period. * At the end of the 12-week study diet period, participants will provide additional hair, blood, and fat tissue samples, and will have a second metabolism assessment in the metabolic chamber....
Gender: MALE
Ages: 18 Years - 65 Years
Updated: 2026-08-28
1 state
NCT07792876
Endurance Trial: Ketone and Carbohydrate Supplementation
This randomized, double-blind, crossover study investigates the effects of exogenous ketone supplementation on physical and cognitive performance in amateur endurance athletes during exhaustive exercise. Participants will complete three 3-hour cycling sessions under different nutritional conditions: carbohydrate alone (CHO), carbohydrate plus ketone (CHO-KET), and placebo (PLA). The study will assess cognitive function through validated computerized tests, physical performance via distance covered, and metabolic responses through blood biomarkers. Additionally, peripheral blood mononuclear cells (PBMCs) will be collected and cultured with LPS or not. Other PBMCs co-cultured with neuronal cells (SH-SY5Y) to investigate neuro-immune interactions. The primary hypothesis is that ketone supplementation will preserve cognitive function and enhance physical performance during prolonged exhaustive exercise compared to carbohydrate supplementation alone, potentially through anti-inflammatory mechanisms and alternative energy substrate provision.
Gender: MALE
Ages: 20 Years - 50 Years
Updated: 2026-08-28
1 state
NCT07751731
Survey to Determine Incarcerated Persons' Views on Surrogate Decision Making
Background: About 180,000 of the people in US prisons are over 55 years old. Aging people often cannot make medical decisions on their own. People who cannot make their own decisions must rely on a "surrogate." A surrogate is someone who helps the person's doctor make decisions for them. Researchers want to conduct a survey to ask people in prison who they would like to be their surrogates. But first, they need to find out if their survey questions are clear and easy to understand. Objective: To get imprisoned people's feedback on survey questions about surrogate decision making. Eligibility: People currently imprisoned in a US facility with access to Edovo. They must be able to read and write in English. Design: Participants will answer 26 survey questions. The questions will be on the Edovo Learn software platform. After each question, they will be asked: "Was this question clear? If not, please explain in the box below what you found unclear. Also, if you have any suggestions for how we might make the question clearer, please include them." Participants will be asked to imagine themselves in a situation where they cannot make their own medical decisions. They may skip questions or stop the survey if they want. No information that identifies them will be collected. The survey will take about 15 minutes.
Gender: All
Ages: 18 Years - 120 Years
Updated: 2026-08-28
1 state
NCT06577454
Measuring the Effects of Neurostimulation on Risky and Ambiguous Decision-Making Capacity in People With and Without Substance Use Disorder
Background: The purpose of this study is to understand how a type of brain stimulation, transcranial magnetic stimulation (TMS), may help those who use opioids such as heroin or methadone. TMS uses brief magnetic pulses to affect brain activity, and is approved by the FDA to treat some mental health problems and substance use. We will evaluate how TMS may help make it easier to make certain kinds of decisions that could help one manage their opioid use. Our findings may provide support for the use of brain stimulation as a treatment to reduce opioid use. Objective: To understand how TMS affects brain activity associated with decision making in people who do and do not use opioids. Eligibility: People aged 18 to 60 years with an OUD. Healthy volunteers are also needed. Design: Participants will have up to 3 clinic visits over 1 to 3 months. All participants will be screened to check if they are eligible to take part in this study. This study is completed in two parts. All eligible participants will complete the first part of the study. In the first part, you will receive one baseline magnetic resonance imaging (MRI) scan so we can take pictures of your brain while you complete computer tasks in the scanner. In these tasks, you will be asked to identify colors of words, view different images and play a game in which you can win money. If you can safely receive TMS, you will be invited to complete the second part of the study. In this part of the study, you will receive TMS and MRI over 2 sessions. For TMS, a coil will be placed on your head and a short electrical current will pass through the coil to create a magnetic pulse that stimulates your brain. You will also repeat the MRI scan and computer tasks. During one of the TMS visits you will receive active or real TMS. In the other, you will receive sham or placebo TMS, which feels like real TMS but does not affect the brain. You will receive both types of TMS. In all sessions, your urine and breath will be tested for drugs and alcohol, and you will complete questionnaires about mood and health....
Gender: All
Ages: 18 Years - 60 Years
Updated: 2026-08-28
1 state
NCT02471352
Studies of Dermatologic Diseases Biospecimen Acquisition Protocol
Background: \- Skin disease can have many causes. It can have widespread consequences, and in rare cases can lead to death. Researchers want to determine the causes of various types of skin diseases and find a way to treat them. Objectives: \- To determine the causes of various skin diseases and find ways to treat them. Eligibility: * People ages 2 and older who have: * A skin disease or at risk of developing a skin disease OR * A family member of persons with a skin disease * Healthy volunteers ages 2 and older Design: * Participants will be screened under a separate protocol. * Participants may take a survey about how their skin condition affects their quality of life. * Participants will have a medical history and a physical exam including a detailed skin exam. Pictures will be taken of their skin to document any skin disease. * Participants will have specimens collected. This may include: * Several teaspoons of blood taken at each visit * Stool samples * Nail and body fluid (like saliva) samples * Cheek swabs. The inside of the cheek will be scraped for about a minute in each direction to collect cells. * Collection of skin samples with: * A swab (like a Q-tip) * Gently scraping skin to remove the outer layers of cells * Applying and removing 1-inch pieces of tape * Participants may have up to 4 skin biopsies in 12 months, with 4 separate biopsies taken each time. * An area of skin will be numbed with an injection. * A piece of skin the size of a pencil eraser will be removed using a small instrument. * A flat scar usually develops at the biopsy site.
Gender: All
Ages: 1 Day - 100 Years
Updated: 2026-08-28
1 state
NCT02339012
Genetic and Epigenetic Signatures of Translational Aging Laboratory Testing (GESTALT)
Background: \- Biomarkers are substances in people's blood and tissues. They help researchers understand diseases and signs of aging. Scientists want to do more research on biomarkers to find ways to improve quality of life in old age. Objective: \- To learn more about biomarkers and their relationship to aging. Eligibility: \- Adults at least 20 years old who weigh at least 110 pounds and have a body mass index below 30. They must agree that their genetic samples can be collected, studied, and stored. Design: * Participants will be screened with medical history, physical exam, EKG and blood and urine tests. * Participants will have 3-day visits. They will return every 2 years. * All visits include: * Blood and urine collection * Physical performance tests * Health questionnaires * Memory and problem-solving tests * Magnetic Resonance Imaging (MRI) and Computerized Tomography (CT) scans. * Muscle metabolism/ exercise tests * Taste strips * Muscle and/or skin biopsies/ red light therapy * Retinal imaging/ eye tracking * Sleep study * ODD visits also include: * Cytapheresis * Bone marrow aspirate * EVEN visits also include: * Hyperglycemic CLAMP * Lumbar Puncture (LP) * Continuous Glucose Monitor (CGM)
Gender: All
Ages: 20 Years - 120 Years
Updated: 2026-08-28
1 state
NCT01130545
Imaging Techniques in MRI
Background: \- Magnetic resonance imaging (MRI) scans must be performed according to specified sets of parameters that provide optimal images of each organ and each area of the body. These scanning parameters are often specific to the institution or organization at which they are employed, and may also depend on the manufacturer of the MRI scanning equipment. Because MRI scanning equipment is always being updated and upgraded, researchers are interested in developing new and optimized scanning parameters for MRI scans. Objectives: \- To improve current methods and develop new techniques for magnetic resonance imaging. Eligibility: * Individuals 18 years of age and older who are either volunteers or current NIH protocol participants. * Participants must not have any medical history factors (e.g., extreme claustrophobia, history of metal implants) that would prevent them from receiving MRI scans. Design: * Participants will have at least one MRI scan that will last from 20 minutes to 2 hours (most scans will last between 45 and 90 minutes). The total time commitment for most visits will be approximately 4 hours from start to finish. * Some MRI techniques require standard monitoring equipment or specific procedures during the scanning, such as an electrocardiogram. * Participants will have blood samples taken at the time of the scan. Some MRI studies will require the use of a contrast agent that will be administered during the scan. * Volunteers may be asked to return for additional MRI scans over the course of a few years. Follow-up scans may be done on the same part of the body or on different parts of the body. No more than one MRI scan will be performed in any 4-week period for this protocol....
Gender: All
Ages: 18 Years - 100 Years
Updated: 2026-08-28
1 state
NCT00862433
Vitamin E Pharmacokinetics and Biomarkers in Normal and Obese Women
Background: * Vitamin E is an antioxidant that reduces the damaging effects of oxygen in the body. Most American men (90%) and women (96%) do not get enough vitamin E from their diets; however, the amount of vitamin E needed by the body has been studied only in men, not women. In addition, it is unknown whether another antioxidant, vitamin C, helps vitamin E in protecting the body. Because vitamin E is a fat-soluble vitamin, how much body fat a person has could affect the amount of vitamin E needed for protection. Objectives: This study has three arms to examine vitamin E requirements: * To determine the amount of fat required to get the best vitamin E absorption from a meal. * To determine the amount (i.e., best dose) of vitamin E that must be consumed before it can be measured in the blood. * To examine how vitamin E and vitamin C work together in the body, in conjunction with diet and vitamin supplements. Eligibility: * Arms 1 and 2: Women between the ages of 18 and 40 years who have a normal weight and body mass index (BMI) of 27 or less. * Arm 3: Women between the ages of 18 and 40 years who have a normal weight (BMI 27), who are overweight (BMI \> 27), or who are overweight (BMI \> 27) and have non insulin-dependent diabetes. Design: * Arm 1: Five studies, each lasting 1 month with 1 month off between studies (total study = 10 months). Participants will take 500 1,000 mg of vitamin C twice daily for 2 weeks before admission to the clinical center for 1 week. * Study 1: Participants will eat breakfast containing a known amount of fat, after which they will take a vitamin E pill as well as receive an IV injection of vitamin E. Other foods contain only negligible amounts of vitamin E. Blood and urine samples will measure levels of vitamin E and other substances. * Studies 2 5: Outpatient visits will consist of the same tests as in Study 1; however, the amount of fat in the breakfast will range from 0% to 40% in random order. During one of the studies, an adipose tissue biopsy will be collected to determine how much vitamin E is in the tissues. * Arm 2: Five studies, each lasting 1 month with 1 month off between studies (total study = 10 months). Preparation for Arm 2 is the same as in Arm 1. The proportion of fat, muscle, and water in the body will also be measured. * Study 1: Participants will eat breakfast containing 30% fat, after which they will take a vitamin E pill as well as receive an IV injection of vitamin E. Conditions and procedures are the same as in Arm 1. * Studies 2 5: Outpatient visits will consist of the same tests as in Study 1; however, the amount of vitamin E in the breakfast will range from 2 to 30 mg in random order. * Arm 3: Outpatient (2 to 6 weeks) and inpatient studies (4 to 6 weeks). * Outpatient study: Participants will take 500 1,000 mg of vitamin C daily and provide blood and urine samples, as well as an adipose tissue sample. * Inpatient studies: Two vitamin E inpatient studies. Before these begin, participants vitamin C blood levels will be reduced by means of a diet low in vitamin C. Blood tests will determine how quickly vitamin C leaves the body. Once the vitamin C level is reduced, the first vitamin E study will begin. Study A: The procedure for this study is the same as in Arm 2, Study 1. Study B: The procedure for this study is the same as in Study A, except that the participants blood vitamin C levels will be higher.
Gender: FEMALE
Ages: 18 Years - 55 Years
Updated: 2026-08-28
1 state
NCT03394066
Mechanism of Non-invasive Magnetic Stimulation
Background: Transcranial magnetic stimulation (TMS) is form of non-invasive brain stimulation. It is approved to treat depression. TMS may help decrease drug craving. It is important to understand how TMS affects the brain. Such a better understanding would help to design ways to treat drug addiction. Objectives: To learn how TMS affects the brain when it stimulates an area in the front of the brain. Also, to see how the stimulation affects the area stimulated and other connected areas. Eligibility: Healthy, right-handed adults ages 18-60 who are non-drug users. Design: Participants will be screened under protocol 06-DA-N415. Participants will have at least 3 visits. The first visit will last about 3 hours. All other visits will last up to 6 hours. Participants cannot use drugs or alcohol at least 24 hours before a visit. They cannot have more than half a cup of a caffeinated drink at least 12 hours before a visit. Each visit will include a brief medical history update, urine test for drugs and pregnancy (if female), a breath test for alcohol and smoking, and questionnaires. Participants will have a TMS orientation visit. A wire coil will be placed on the head. An electrical current will pass through the coil to create a magnetic pulse that stimulates the brain. The other visits will include 2 sessions of TMS-MRI. Participants will lie on a table that slides into a cylinder. The TMS coil and the MRI coil will be placed over the head. Pictures will be taken of the brain with and without stimulation. Participants will complete a questionnaire about how they feel before and after each TMS session and in a follow-up call 1-3 days after their last session.
Gender: All
Ages: 18 Years - 60 Years
Updated: 2026-08-28
1 state
NCT06552754
Cybersickness Prevention and Mitigation in Virtual Reality for Healthy Volunteers
Background: People use virtual reality (VR) technology to play games, socialize, work, or receive medical care. Some people have "cybersickness" after using VR. Cybersickness is similar to motion sickness. Symptoms include eye strain, nausea, dizziness, or headache. The symptoms are usually mild and go away after the person stops using VR. New software called Motion Reset is being designed to reduce symptoms of cybersickness during VR use. Objective: To see if Motion Reset software can reduce cybersickness in people using VR. Eligibility: Healthy adults aged 18 to 60 years. Design: Participants will have 1 clinic visit that will last about 1 hour. They will answer questions about how they are feeling. They will learn how to use the VR headset and the handheld game controllers. The study will be broken into 2 parts. For the first part, participants will be assigned to 1 of 3 groups: Group 1 will participate in a VR experience designed to prevent cybersickness. They will view screens and move around while they press buttons on a controller. Group 2 will participate in a VR experience that is not designed to prevent cybersickness. They will view screens and move around while they press buttons on a controller. Group 3 will have no VR experience. Participants will complete 2 questionnaires about their experiences in the first part of the study. For the second part, all participants will spend up to 20 minutes playing a commercial VR game called Jurassic World Aftermath. Every few minutes, they will be asked if they are experiencing discomfort. After playing the game, participants will complete 12 questionnaires about their experience....
Gender: All
Ages: 18 Years - 60 Years
Updated: 2026-08-28
2 states
NCT04799301
Developing Biomarkers of Dietary Intake: Dose Dependent Measurement of Sugar Intake
Background: Diet is one of the most modifiable behaviors affecting health. But diet assessment measures that are based on self-report can be inaccurate. Researchers want better ways to address the role of diet in chronic disease. They want to see if stable isotopes can be used to better assess what people eat. Objective: To see if stable isotopes can help scientists identify things people eat. Eligibility: Healthy adults ages 18 to 65 Design: Participants will be screened with a medical history and physical exam. They will have blood and urine tests. These tests will be repeated during the study. Participants will stay in the inpatient unit of the NIH in Phoenix, Arizona, for 13 weeks. For 7 days, participants will eat a diet prepared by the NIH kitchen. They will get balanced meals that are 50% carbohydrates, 20% protein, and 30% fat. Then participants will be randomly placed on one of 3 diets containing different percentages of carbohydrates from soda. Participants height and weight will be measured. The amount of fat and muscle in their body will be measured by body scans that are similar to x-rays. Participants will have oral glucose tolerance tests. They will consume a sugar drink and then give blood samples over 3 hours. Participants will give hair and stool samples. Participants will complete a diet questionnaire. It assesses their food intake over 24 hours. Participants will complete behavioral questionnaires and computer performance tests. Participants will have fat biopsies taken from their stomach and thigh. Participants will have three 24-hour stays in a metabolic chamber. It is used to measure metabolism.
Gender: All
Ages: 18 Years - 65 Years
Updated: 2026-08-28
1 state
NCT00071045
Collection of Tissue Specimens From Patients With Solid Tumors or Blood Disorders and Their HLA-Compatible Family Members
This study will collect biological samples for use in research experiments aimed at better understanding the clinical features of certain diseases. The specimens may be used to evaluate the effectiveness of known therapies, refine treatment approaches, identify potential new therapies, and explore opportunities for disease prevention. The following individuals 2 years of age or older may be eligible for this study: * Patients with a cancerous solid tumor or a cancerous or non-cancerous blood disorder who are being screened for or who are enrolled in a treatment study at the NIH Clinical Center * HLA-compatible donor family members (18 years of age or older) of the above patients who are being evaluated for or are enrolled in an NIH study as a stem cell transplant donor * Patients with a cancerous solid tumor or a cancerous or non-cancerous blood disorder or a bone marrow failure condition who cannot participate in an NIH treatment protocol or travel to the NIH Clinical Center and who are referred for participation through their home health care provider. Research samples will be collected from participants when blood is drawn or bone marrow, urine, or stool is collected, or tumor or other tissue is biopsied as part of their general medical care. Investigators may periodically request an additional sample of blood, stool, or urine. Participants who are 18 years of age or older may donate a large number of white blood cells through a procedure called leukapheresis. This procedure is not part of general medical care and would be done for research purposes only. For apheresis, a catheter (plastic tube) is placed in a vein in the subject's arm. Blood flows from the vein into a cell separator machine, where the white cells are separated from the red cells, platelets, and plasma by a spinning process. The white cells are removed and collected, and the rest of the blood is returned to the subject through a second tube placed in the other arm. ...
Gender: All
Ages: 2 Years - 100 Years
Updated: 2026-08-28
1 state
NCT01747213
Bisnorcymserine in Healthy Adult Volunteers
Background: \- Alzheimer s disease (AD) is a brain disease that impairs memory, cognitive abilities and the ability to function independently. It is the most common cause of dementia in older people. It is caused by abnormal proteins in the brain that affect how neurons communicate with each other. Researchers are looking for drugs that can slow down the disease or treat its symptoms. One drug, called bisnorcymserine (BNC), may help improve brain function and symptoms in people with AD. BNC is designed to block a chemical that affects how neurons communicate with each other. Researchers want to see how BNC works in healthy older volunteers. Objectives: \- To look at how the body processes bisnorcymserine taken by mouth and how safe it is for healthy older volunteers. Eligibility: \- Healthy volunteers at least 55 years of age. Design: * Participants will be screened with a physical exam, medical history, and blood and urine tests. * Within 3 weeks from the screening visit, participants will come to the National Institute on Aging clinical unit for a 2-night stay. On the morning of the second day, they will take either a BNC capsule or a placebo. They will not know which tablet they are taking. * Blood samples will be collected frequently throughout the second and third days of the study visit. The last blood sample will be collected about 32 hours after taking the study capsule. Participants will have heart function tests and other exams during the visit. Once the tests are done, they will leave the clinical center. * Participants will have a final follow-up visit about 1 week after leaving the clinical center.
Gender: All
Ages: 55 Years - Any
Updated: 2026-08-28
1 state
NCT02379429
Care of the Urothelial Cancer Patient and Prospective Procurement of Urothelial Cancer Tissue
Background: Urothelial cancer is cancer of the bladder, ureter, and urethra. Researchers want to better understand what changes in a person s cells and genes cause this cancer to form. This may help them find new ways to treat it. Objective: \- To perform DNA sequencing to help researchers learn the differences between normal tissue and tumor tissue. Also, to learn how molecular changes - including gene changes - might help predict the course of disease and how people respond to therapy. Eligibility: \- Adults age 18 and older who have or are suspected of having urothelial cancer or an inherited disorder that raises their risk of getting bladder cancer. Design: * Participants will be screened with a physical exam. Their medical records and tissue samples will be reviewed. * Eligible participants will give tissue blocks of their original tumor. The blocks will be put in a tissue bank. * Participants medical records may be reviewed. * Participants may have a medical history and physical exam. * Participants may have blood and urine tests. They may have imaging scans. They may give urine, blood, and saliva samples. These samples may be used in future research. * If participants need surgery for their cancer, researchers will keep some of the tissue (both tumor and normal tissue). The tissue may be used in future research. * Participants will go back to the Clinical Center in 6 months. They may give saliva, urine, and blood samples. After 6 months, they will be seen by their local doctor for standard post-surgical visits. * Participants will be called every 6 months to give health updates.
Gender: All
Ages: 18 Years - 120 Years
Updated: 2026-08-28
1 state
NCT07706686
Phase 1 Challenge Study Using rDEN2delta30-7169 to Evaluate Host-Pathogen Interactions in Primary, Homotypic, and Heterotypic Dengue Virus Infection
Background: Dengue is a viral disease spread by mosquitoes. Most people bitten by mosquitoes carrying dengue viruses do not get sick, but severe cases can cause shock, internal bleeding, and death. There are no treatments for dengue. To develop treatments, researchers need to understand more about what dengue viruses do in the body. Objective: To infect healthy people with a mild dengue virus to study how their body responds. Eligibility: People ages 18 to 50 years with or without a history of dengue virus infection. Design: Participants will be screened. They will have a physical exam with blood tests. The tests will show whether they have ever been infected with dengue or related viruses in the past. At their first study visit, participants will receive an injection of dengue virus into the arm. The injected virus is weaker than the natural virus, so any symptoms should be milder. Participants will have a total of 11 study visits over 6 months; 8 of those visits will be in the first month. Blood will be drawn at each visit. Some visits will include ultrasound exams of their internal organs. They will discuss any symptoms they are having. Any rashes they develop may be photographed. Two procedures are optional: Participants may have up to 5 lymph node aspirations and 3 bone marrow biopsies during the study. For both procedures, a needle will be inserted into the tissues to draw out immune cells. Two more visits are optional: 1 visit up to 2 months before receiving the virus, for lymph node or bone marrow samples, and 1 about a year after for a blood draw....
Gender: All
Ages: 18 Years - 50 Years
Updated: 2026-08-28
1 state
NCT06868914
Phase I Trial of High-Density Theta Burst Stimulation (hdTBS)
Background: Transcranial magnetic stimulation (TMS) uses magnetic pulses to affect brain activity. A type of TMS called theta burst stimulation (TBS) is approved to treat people with major depression. Researchers have developed a new form of TBS called high-density TBS (hdTBS). They hope hdTBS will work better than TBS. But first they need to test the new treatment in healthy adults. Objective: To test hdTBS in healthy adults. Also, to compare the aftereffects of hdTBS and TBS. Eligibility: Healthy adults aged 22 to 60 years. Design: Participants will have 4 clinic visits over about 3 to 4 weeks. They must abstain from drugs and alcohol and limit caffeine before visits. At their first visit, participants will be oriented to TBS. They will wear a cap and earplugs. A device with round coils will be placed near their head. When a brief electric current passes through the coil, it generates a magnetic pulse that stimulates the brain. Participants may feel a pulling sensation on the skin under the coil. Their fingers may move involuntarily. At their next 3 visits, participants will receive either TBS or sham TBS. A sham TBS uses a low magnetic field to minimize the effects of the treatment. Participants will have up to 9 electrodes placed on 1 arm. These electrodes will measure the electrical activity in their muscles. Each TBS session will be videotaped. At every visit, participants will answer questions about their health, including substance use. They will perform 2 tasks to test their thinking skills. They will perform a test on a computer to test their reaction time....
Gender: All
Ages: 22 Years - 60 Years
Updated: 2026-08-28
1 state
NCT05545306
The Effects of Increasing Caloric Intake on Diet-Induced Thermogenesis and 24h Energy Expenditure
Background: Diet-induced thermogenesis (DIT) is the amount of energy one's body uses to eat food, absorb the nutrients from the food, and process those nutrients. Researchers would like to understand more about how changing the balances of protein, fat, carbohydrates, and total calories in the diet can affect DIT. Objective: To learn how different diets can change a person's DIT. Eligibility: Healthy people aged 18 to 60 years who have not intentionally lost weight in the past 6 months. Design: Participants will stay in a clinic for about 35 days. They will eat only the food provided. They will receive 8 different diets during the study, including 7 test diets. Participants will undergo multiple tests. They will be screened with blood and urine tests and a test of their heart function. During the first few days: Their waist, thigh, and neck circumference will be measured. They will have a DXA scan: They will lie on a padded table for about 20 minutes while an instrument measures the amount of fat in their body. They will be tested for diabetes. They will answer questionnaires about topics including eating behavior, hunger, and stress. Throughout the study: Their weight will be measured daily. Blood tests will be repeated. They will stay in a metabolic chamber a total of 9 times. They will remain in a closed room for 24 hours while researchers monitor the room temperature and levels of oxygen and carbon dioxide. Participants will collect all their urine for each 24-hour period. ...
Gender: All
Ages: 18 Years - 60 Years
Updated: 2026-08-28
1 state