Clinical Research Directory
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Tundra lists 402 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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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: 2026-09-01
1 state
NCT01915212
Study of the Safety of a Particular Herpes Vaccine in Adults With or Without Herpes Infection
Background: \- Herpes simplex virus type 2 (HSV-2) is a major cause of genital herpes. It can also cause serious infection in newborns and in people with weakened immune systems. It increases the risk of getting an HIV infection and of spreading HIV to someone else. Therefore, a vaccine that could prevent genital herpes could improve the general health of the world s population. Researchers want to study whether a new vaccine, HSV529, which may be used in the future to prevent herpes infections, is safe. Objectives: \- To test whether a new herpes vaccine is safe. Eligibility: \- Healthy adults 18 40 years old. Design: * Participants will have 3 vaccination visits, 7 follow-up visits, and 3 follow-up phone calls over 1 year. * Each vaccination visit will last about 4 hours. * Participants will be screened with a medical history and physical exam. * Participants will have a blood sample taken. * Participants will be given the vaccine or a placebo, by injection from a needle. They will be monitored for 30 minutes to check for any allergic reaction. * Participants will be given a diary card to record any symptoms they may feel later. * At follow-up visits, participants will give a blood sample and answer health questions. * In the phone calls, participants will answer health questions.
Gender: All
Ages: 18 Years - 40 Years
Updated: 2026-09-01
1 state
NCT03407079
Effects of Sucralose on Drug Absorption and Metabolism (The SweetMeds Study)
Background: Artificial sweeteners like sucralose are found in many foods and drinks. Sucralose might affect hormones and cause health changes. Objective: To see if sucralose changes how medicines are absorbed and processed, how hormones are secreted, gut bacteria, and how fat cells are metabolized. Eligibility: People ages 18-60 who: * Are black or Hispanic * Weigh more than 110 pounds * Have a body mass index of 25-40 * Do not have a condition that requires drug treatment Design: Participants will be screened with: * Medical history * Physical exam * Blood, heart, and urine tests Participants must not eat or drink anything with artificial sweeteners throughout the study. Over 7 days, Participants will answer questions, and give daily urine samples and 1 stool sample. Participants will repeat these throughout the study. Overnight Visit 1: participants will fast starting the night before. They will get breakfast at the visit. The visit includes: * An IV will be placed in the arm. Participants will get 2 tablets of medicines. Blood will be drawn several times over 24 hours. * A piece of fat tissue may be taken from the abdomen (biopsy). * Participants will have a sweet drink. Blood samples will be taken over 2 hours. Then participants will be randomly assigned to take either a sucralose capsule or placebo. They will take it twice a day for 2 weeks. They will complete two 24-hour food diaries. Overnight Visit 2 repeats Visit 1 except the biopsy. Then participants will take the capsules for another 2 weeks. Overnight Visit 3 repeats Visit 1. Participants may be contacted by phone within 4 weeks after they finish.
Gender: FEMALE
Ages: 18 Years - 60 Years
Updated: 2026-09-01
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: 2026-09-01
1 state
NCT00353158
A Pilot of Pediatric/Adult Study of Gene Expression Profiling and Clinical Characterization of Phototoxicity
This study will examine the phototoxicity, a reaction to light that is like exaggerated sunburn, which occurs in people who take medications such as voriconazole, a medication used to fight fungus. Sunscreens might protect the skin from the reaction. Although phototoxicity from voriconazole is not completely understood, it may be related to how that medication is metabolized in the liver by enzymes called cytochrome P450 enzymes-and mainly by one known as 2C19. A way to evaluate phototoxicity is through microarrays, which measure how much each gene is expressed in cells from tissues such as skin. Patients ages 8 and older who are scheduled to begin taking or who currently take voriconazole may be eligible for this study. Also, patients ages 18 to 45 in good health who have skin tone known as Type 2, which usually burns and tans only slightly following sun exposure, may be eligible. All patients will visit the Dermatology Clinic. They will complete two questionnaires, on medical history and medications, as well as the skin response to sunlight, and donate about 3 teaspoons of blood. Patients who are scheduled to take voriconazole will visit the clinic four times, that is, two visits 2 consecutive days before beginning the medication and two visits on 2 consecutive days after taking it for at least 7 days. Each visit will take 1 to 2 hours. Patients about to take voriconazole will have a blood test and undergo a physical exam of the skin test site, on the buttocks. Researchers will take photographs of the specific site and do tests to measure skin reaction to ultraviolet (UV) light. UV light will be shined on 15 small areas of the skin, each 1 x 1 centimeters. After 24 hours, any redness that occurs on the skin will be checked. Afterward, patients will begin taking voriconazole according to directions by the researchers. At 10 or more days later, patients will visit the clinic. Sunscreen will be applied and 1 hour later after administration of voriconazole, a blood sample will be drawn to check the level of medication. Then UV light will be shined on 23 areas of skin 1 x 1 centimeters. More photographs will be taken of test sites to record changes in skin redness. On the next day, the skin response will be evaluated. Participants in the control group will be asked to avoid UV radiation by wearing hats and clothing, and using sunscreen. They will be given the doxycycline, an antibiotic, and undergo procedures with UV light shined on small areas of the skin, on the buttocks. Control participants will have 7 study days, with visits lasting from 1 to 3 hours and probably not exceeding 8 hours. They will have two shave biopsies on Study Day 2 and on Study Day 7 to determine how the skin has responded to UV light exposures.
Gender: All
Ages: 8 Years - 100 Years
Updated: 2026-09-01
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: 2026-09-01
1 state
NCT03538600
Sample Collection From Healthy Volunteers for Assay Optimization
Background: The Laboratory of Immune System Biology (LISB) works with other labs at the National Institutes of Health. They study how parts of living things come together to make a whole. LISB designs and improves research tests on human samples like blood and cells. In order to do its work, LISB needs to have a lot of these samples available. Objective: To collect biological specimens to use for designing and improving research tests. Specimens include blood, stool, saliva, and skin/mucosal swabs. Eligibility: Healthy people ages 3-80 Design: Participants will be screened with an interview about their general health and their medical history. They will have a physical exam and blood tests. If the results of the screening are normal, participants will be asked to give one or more of these samples: Blood will be drawn from an arm vein with a needle and syringe. Mucus and skin will be collected by rubbing the area with a cotton swab. The areas may include the top of the tongue, inside the cheek, nostrils, behind the ear, elbow pit, or vagina. Participants will spit into a tube to collect saliva. Participants will pass stool into a plastic container that fits in the toilet under the seat. They will get sampling kits and instructions. Over the next 5 years, if more samples are needed, participants will be contacted to set up another visit to the NIH. These visits will each take about 1 hour. About every 2 years, when participants come to NIH for a visit, extra blood will be collected. It will be tested for HIV and hepatitis B and C. ...
Gender: All
Ages: 3 Years - 80 Years
Updated: 2026-09-01
1 state
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: 2026-09-01
1 state
NCT06299410
PET Study to Evaluate Brain Receptor Occupancy, Safety and Pharmacokinetics of ITI-1284 in Healthy Subjects
The study will be conducted as an open-label and single-center study to evaluate the occupancy of ITI-1284 to the dopamine D2 receptor, serotonin 2A (5-HT2A) receptor, and serotonin transporter (SERT) in healthy subjects.
Gender: All
Ages: 18 Years - 55 Years
Updated: 2026-09-01
1 state
NCT02390765
Children s Growth and Behavior Study
Background: \- Studies show that many factors affect children's eating behavior and health. These include sleep, mood, thinking skills, and genetics. Studying children over time may identify children at higher risk for eating-related health concerns. Objective: \- To understand how genes and environment influence eating behavior and health over time. Eligibility: \- Children ages 8-17 in good general health. Design: * Screening visit 1: Medical history, physical exam, body measurements, and questions. * 14 days: Participants will wear a wrist monitor and answer smartphone prompts about eating and mood. They may give a stool sample. * Screening visit 2: * Body measurements. * Saliva, urine, and blood samples. * Heart tests. * Meals provided (after fasting overnight). * Questionnaires and interview. * Behavior, thinking, and exercise tests. * X-ray of left wrist and full body.\<TAB\> * Some parents may have medical history, physical exam, and questions at screening visits. They may answer questions at the yearly visits. * Participants will have up to 6 yearly visits. They will give a urine sample and body measurements, and repeat the X-rays. They will have questions and behavior and thinking tasks. They may give stool samples. Visits will range from 3 to 8 hours. * Participants may choose to participate in other studies: * Stress and Hormones, 1 visit: While resting, participants will give saliva samples and have their heart monitored. Then they will do math. They will repeat the resting part, then do a computer task. * Brain Imaging, 2 visits: Twice, participants will perform tasks with a magnetic cone on their head then answer questions. Once, they will have an MRI, lying still in a scanner with a coil on their head. Before the first visit, participants will collect at-home saliva samples once a day for three days. During both visits, participants will perform tasks and answer questions that gauge their thinking skills and mood. * Experiment 3 (sleep/fatigue): Participants will complete 2 additional visits. During these visits, participants will complete a task on the computer for 2 hours, or watch a movie for two hours. After completion of the task/movie, they will answer questions and be provided with food. Participants will be compensated for the time and inconvenience involved with completing study procedures.
Gender: All
Ages: 8 Years - 100 Years
Updated: 2026-09-01
1 state
NCT00084305
Analysis of Specimens From Individuals With Pulmonary Fibrosis
The etiology of pulmonary fibrosis is unknown. Analyses of blood, genomic DNA, and specimens procured by bronchoscopy, lung biopsy, lung transplantation, clinically-indicated extra-pulmonary biopsies, or post-mortem examination from individuals with this disorder may contribute to our understanding of the pathogenic mechanisms of pulmonary fibrosis. The purpose of this protocol is to procure and analyze blood, genomic DNA, and specimens by bronchoscopy, lung biopsy, lung transplantation, extra-pulmonary biopsies, or post-mortem examination from subjects with pulmonary fibrosis. In addition, blood, genomic DNA, clinically-indicated extra-pulmonary biopsies, as well as bronchoscopy and post-mortem examination specimens may be procured and analyzed from relatives of subjects with hereditary forms of pulmonary fibrosis; blood, genomic DNA, and bronchoscopy specimens may be procured from healthy research volunteers....
Gender: All
Ages: 18 Years - 115 Years
Updated: 2026-09-01
1 state
NCT03253705
Samples From Human Subjects to Facilitate Basic, Translational and Clinical Research
Background: This study is designed to provide samples to help us study the genes your blood cells are making as well as the proteins, sugars, fats, vitamins and other metabolites found in your blood or urine. Blood samples may also be collected to make special cells. These are called induced pluripotent stem cells or iPSCs. Pluripotent stem cells are cells that can be converted into any type of cell. Researchers want to study in the lab iPSCs that are derived from blood samples. Objective: To collect samples to help study genes, proteins, sugars, fats, vitamins, and other metabolites found in blood or urine. Eligibility: Healthy volunteers and patients ages 18 and older Design: First-time research study participants at NIH will have an initial visit for this study that should last no more than 1 hour. All other visits should last 20 30 minutes. Participants will undergo a limited history and physical exam. Participants may have routine blood and urine tests. If participants are giving a blood sample, they must have a hemoglobin level checked in the past 12 months to make sure it is safe for them to give a blood sample for research. Participants may have a venous blood collection. They may do this at several visits. They will lie on a recliner or couch or sit in a chair. A needle will be placed into a vein in the hand or arm, using sterile techniques. Blood will be withdrawn into multiple syringes or tubes. Participants may be asked to provide urine in an appropriate container
Gender: All
Ages: 18 Years - 100 Years
Updated: 2026-09-01
1 state
NCT07797478
A Study of RO7890597 in Healthy Adult Volunteers
This study will evaluate the safety, pharmacokinetics (PK), and activity of single and multiple doses of RO7890597 compared with placebo in healthy volunteers. The study includes single ascending dose (SAD) stage, multiple ascending dose (MAD) stage, food-effect and proton pump inhibitor (PPI) stages, and a supplemental drug-drug interaction (DDI) stage.
Gender: All
Ages: 18 Years - 65 Years
Updated: 2026-09-01
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: 2026-09-01
1 state
NCT00428987
Physical and Behavioral Traits of Overweight and Obese Adults
This study will describe the phenotype (physical and behavioral traits) of overweight and obese people. It will characterize the hormones, metabolism, food preferences, fitness and physical activity levels, sleep patterns and thought processes in people with and without weight problems. Genetic material will be collected for studies of the internal codes that influence body weight. People over 18 years of age from all weight categories (lean, overweight, obese) who are reasonably healthy may be eligible for this study. Participants undergo the following tests and procedures: * Physical exam, electrocardiogram, blood and urine tests, instructions for recording food intake for 7 days * Metabolic studies for menstruating women. * Resting metabolic rate to study how many calories the body burns at rest. * Mixed meal test to measure hormones such as insulin that regulate blood sugar. * Glucose tolerance test to determine how sensitive the body is to insulin. * 24-hour energy expenditure to measure the amount of oxygen breathed in and the amount of carbon dioxide breathed out. * Repeat 24-hour energy expenditure. * Diurnal blood sampling and temperature assessment to study the body s internal clock. * Air-displacement plethysmography (Bod Pod) to measure body composition. * Dual energy x-ray absortiometry (DEXA) to measure body fat and bone density. * Repeat Bod Pod and DEXA. * Anthropometric measurements and bioelectrical impedance to measure height, weight, and circumferences, skinfold thickness, fluid status and percentage body fat. * Bromide dilution to measure the amount of water not in cells in the body. * Doubly labeled water to measure the amount of calories burned in a 7-day period. * 24-hour diet reports. * Endothelial reactivity to measure how the blood vessels stretch or dilate for assessing cardiovascular health. * Treadmill or bicycle exercise capacity test. * Physical activity monitor. * Unicorder to detect any breathing difficulties that may interfere with sleep. * Fat and muscle biopsy to look for variations in gene expression in fat tissue and muscle. * Neurocognitive testing to check memory, decision-making, hand-eye coordination, and reasoning. * Evaluation of mood problems and assess personality type. * Evaluation to assess the quantity and quality of pain experienced. * Taste testing to determine the response to bitter, salty, sweet and sour substances. * Occupational therapy evaluation to explore the subject's adaptations, if any, for performing personal, social or professional activities; the subject's views on his or her weight, body size and shape, and strategies to control weight.
Gender: All
Ages: 18 Years - 100 Years
Updated: 2026-09-01
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: 2026-09-01
1 state
NCT01191853
Cellular and Molecular Characterization of the Immune Response in Healthy NIH Employees atBaseline, and After Immunization With the H1N1 or Seasonal Influenza Vaccines
Background: \- Seasonal influenza is a major health problem whose impact is typically reduced by vaccination. The H1N1 (swine flu) influenza virus is an emerging pathogen that has the potential to cause devastating illness and even death in the coming months. Currently, there are limited data on the cellular and molecular immune responses in adult recipients of either the seasonal or the H1N1 influenza vaccines. Objectives: \- To obtain blood and nasal wash samples and perform laboratory studies to characterize the immune response in healthy adult volunteers at baseline and after immunization with the seasonal or H1N1 influenza vaccines. Eligibility: \- Adult employees at least 18 years of age of the NIH Clinical Center who are deemed healthy by a brief medical history and physical examination and routine blood testing. Design: * Before the start of the influenza season, volunteers will receive either the seasonal influenza vaccine or the H1N1 vaccine when it becomes available. If the H1N1 vaccine is available at the start of the season, volunteers will receive both the seasonal vaccine and the H1N1 vaccine. * Blood will be drawn over an 8-week period. Volunteers must not eat anything for 8 hours prior to the blood draw. The sequence of the blood draws is as follows: 2 weeks before vaccination; right before vaccination; and 1, 7, 14, 28, and 60 days after vaccination. * Two to four nasal washings will be collected by a nurse before volunteers receive the vaccination(s) and 28 days after the vaccination. * Prevaccine and postvaccine blood and nasal wash samples will be compared to determine volunteers immune responses. * Research samples will be stored indefinitely and will be used strictly for laboratory experiments.
Gender: All
Ages: 18 Years - Any
Updated: 2026-09-01
1 state
NCT00663611
Growth Hormone Administration and the Human Immune System
Background: \- In elderly individuals, an age-associated decline in the immune system s ability to function is believed to contribute to increased incidence of infection, autoimmune disorders, and cancer. This decline in immune system function may be related to the decline in the body s production of growth hormone, which helps regulate human development and may contribute to the health of the immune system. Researchers are interested in studying whether growth hormone, given as an infusion over time, can improve the function of the immune system and other body systems associated with good health. Objectives: \- To study the effects of growth hormone administration on the immune systems of healthy men. Eligibility: \- Healthy men between 25 and 50 years of age. Design: * This protocol will involve three separate studies: Study I, Study IB, and Study II. Participants in Study I and Study IB may participate in Study II as directed by the researchers. * Participants will be screened with a full medical history and physical examination, and will provide blood, urine, and stool samples; have a glucose tolerance test; and have other tests as required by the researchers. * Participants will have an infusion pump with a small catheter inserted beneath the skin to administer the study chemicals (either growth hormone or placebo). * Study I and Study IB participants will receive pulses of growth hormone through the infusion pump at regular intervals to monitor the body s response to the hormone. Study IB participants will receive a higher dose of growth hormone than Study I participants. * Throughout the study period, all participants will have frequent blood and urine tests, as well as tests of glucose tolerance and metabolism, imaging studies, and other tests as required by the researchers. * Study II participants will be divided into two groups. The first group will receive pulses of either growth hormone or placebo infusion at intervals throughout the day for 4 weeks, followed by an 8-week period without infusions. The second group will receive conventional once-a-day infusion of growth hormone or placebo for 4 weeks, followed by an 8-week period without infusions. * Throughout the study period, all participants will have frequent blood and urine tests, as well as tests of glucose tolerance and metabolism, imaging studies, and other tests as required by the researchers.
Gender: MALE
Ages: 25 Years - 50 Years
Updated: 2026-09-01
1 state
NCT00104325
Cytapheresis of Volunteer Donors
Background: \- National Institute on Aging researchers are looking at studies that require large numbers of white blood cells for lab use. Standard blood samples do not provide enough white blood cells for these studies. Researchers want to use cytapheresis to collect white blood cells from volunteer donors. This procedure can collect larger amounts of white blood cells and reduce the amount of fluid and other cells that are lost. Objectives: \- To use cytapheresis to collect white blood cells for study. Eligibility: \- Healthy blood donors at least 18 years of age. Design: * Participants will be screened according to the usual blood donation procedures. * Participants will provide white blood cells through cytapheresis. The blood cells will be collected in a machine that separates the white blood cells from the rest of the blood. The rest of the blood will be returned to the donor. * Participants may have this type of donation every 56 days (six times per year). They will be asked to become a repeat donor. A donation schedule may be set up. * Once a year, participants will have blood tests to continue to be eligible as a donor.
Gender: All
Ages: 18 Years - 120 Years
Updated: 2026-09-01
1 state
NCT03258580
Sociocultural & Biobehavioral Influences on Pain Expression and Assessment
Objective The current proposal investigates behavioral, psychophysiological, and social processes that may help explain biases and disparate outcomes in pain. Health disparities, or health outcomes that adversely affect disadvantaged populations, are pervasive and apparent in many diseases and symptoms, including pain. Pain is the number one reason individuals seek medical treatment. Health disparities in pain encompass both differences in pain experience and treatment for pain. For instance, research indicates that Black individuals report increased pain and have reduced pain tolerance relative to White individuals, yet doctors are less likely to treat minority patients pain and underestimate their pain experience. This project aims to address this systemic discrepancy by focusing on interpersonal processes that may contribute to these disparities, including socially-relevant responses to pain (i.e. pain expression) and pain assessment (e.g. visual attention). The proposed research aims to determine whether the study of pain expressions and their assessment can yield insights on how social factors shape pain and its treatment. Further, we test the efficacy of potential interventions designed to improve accuracy and reduce biases in pain assessment. If successful, this work will form the foundation of a new research program that will link the field of pain research with the field of social neuroscience, and forge new insights on the critical problem of health disparities in pain. Study population We will accrue up to 700 total healthy volunteers to target 240 completers Design Our overall aim is to understand how social factors influence the assessment and management of pain, and to gain insight into psychosocial processes that may underlie health disparities in pain. We propose a series of studies designed to test these links. First, we will measure pain perception and physiological responses to painful stimuli in a diverse group of individuals to test for sociocultural and biological influences on pain and pain-related responses. In subsequent studies, new participants ("perceivers") will view images of these initial participants ("targets") and will provide estimates of 'targets' pain experience. We will measure a) whether perceivers can accurately estimate 'targets' pain experience; b) whether accuracy differs as a function of similarity between target and perceiver (ingroup vs outgroup); and c) whether individuals can improve accuracy through feedback. Outcome measures Primary outcome measures for all experiments will be decisions about pain (experienced by self or other) measured with visual analogue scales, reaction time, and/or categorical judgments (pain/no pain). We will also measure physiological responses (e.g., facial muscle response, skin conductance, pupil dilation) and brain responses using functional magnetic resonance imaging (fMRI) as secondary outcome measures. We will test whether pain and pain-related responses varies as a function of sociocultural/demographic factors (e.g. race, ethnicity, sex) and whether accuracy in assessing others' pain is influenced by group similarity (i.e. ingroup vs. outgroup) and training (e.g. performance-related feedback).
Gender: All
Ages: 18 Years - 60 Years
Updated: 2026-09-01
1 state
NCT00442195
Collection and Analysis of Blood, Bone Marrow, and Buccal Mucosa Samples From Healthy Volunteers
The Hematology Branch of the National Heart, Lung, and Blood Institute is doing a variety of laboratory research experiments that require blood and tissue samples from healthy volunteers. This protocol provides a mechanism for collecting these tissue samples. Research includes studies of normal and abnormal formation of blood cells, viral blood diseases, the role of the immune system in marrow failure and genetic risk factors for aplastic anemia. Healthy normal volunteers 8 years of age and older may be eligible for this study. Samples are collected as follows: * Blood samples: Participants 8 years of age and older donate up to 4 tablespoons of blood, which is obtained from a needle placed in an arm vein. * Participants 8 years of age and older donate a buccal mucosa sample (cells from the inside of the cheek). The inside of the cheek is scraped gently with a nylon brush. * Participants 18 years of age and older donate a bone marrow sample. The bone marrow is obtained from the hip bone. The skin over the area is wiped clean with alcohol and iodine, and then a local anesthetic is injected under the skin and also into the bone. When the area is numb, a bone marrow aspiration needle is introduced through the bone surface into the marrow. The marrow cells are collected using a syringe connected to the needle.
Gender: All
Ages: 8 Years - 99 Years
Updated: 2026-09-01
1 state
NCT05653037
A Single Ascending Doses Phase I Study to Evaluate the Safety and Pharmacokinetics of RBD4059 in Healthy Subjects
This is a Randomized, Single-blind, Placebo-Controlled Phase I Study to Evaluate the Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of Single Ascending Doses of Subcutaneously Administered RBD4059 in Healthy Subjects. The study will be performed in single ascending dose (SAD) phase in healthy subjects. The decision to escalate to subsequent dose levels will be made by the SRC based on the review of all available safety information and PK/PD data in each cohort. RBD4059, a GalNAc conjugated siRNA, is an FXI-targeted new molecular entity independently developed by Ribo using its proprietary siRNA delivery system - RIBO-GalSTARTM.
Gender: All
Ages: 18 Years - 65 Years
Updated: 2026-09-01
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: 2026-09-01
1 state
NCT02543983
Neurobiology of Suicide
Background: There are no good treatments for people considering suicide. Researchers want to study suicide with questions, blood tests, brain imaging, and sleep studies. They hope to better understand suicide, so they can help suicidal people. Objective: To understand what happens in the brain when someone has thought about or attempted suicide. Eligibility: Group 1: Adults ages 18 70 who have thought about or attempted suicide recently Group 2: Adults ages 18 70 who have thought about or attempted suicide in the past Group 3: Adults ages 18 70 who have depression or anxiety, but have never thought about suicide Group 4: Healthy volunteers the same ages. Design: Participants will be screened in another protocol. Adults who have recently thought about or attempted suicide must be referred by a doctor. They may do up to 3 phases of this study. Groups 2, 3 and 4 will do only Phase 1 and will not get ketamine. Phase 1: 1 week in hospital. Participants will have: Physical exam. Questions about thoughts and feelings. Thinking and memory tests and simple tasks. Blood and urine tests. Two MRI scans. Participants will lie on a table that slides into a metal cylinder that takes pictures. They will have a coil over their head and earplugs and do a computer task. Sleep test. Disks and bands will be placed on the body to monitor it during sleep. Magnetic detectors on their head while they perform tasks. A wrist monitor for activity and sleep. Lumbar puncture (optional). A needle will collect fluid from the back. Shock experiments (optional). Participants will observe pictures and sounds and feel a small shock on the hand. Phase 2: 4 days in hospital. A thin plastic tube will be placed in each arm, one for blood draws, the other to get the drug ketamine once. Participants will repeat most of the Phase 1 tests. Phase 3: up to 4 more ketamine doses over 2 weeks. Participants will have follow-up calls or visits at 6 months and then maybe yearly for 5 years.
Gender: All
Ages: 18 Years - 70 Years
Updated: 2026-09-01
1 state