Healthy Volunteers

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.

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.

The main purpose of this study is to evaluate the safety and tolerability of single and multiple ascending doses of RO7806881 in healthy participants.

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....

The diet is assumed to contribute to many of our present non-communicable diseases. Vegetarian products are instead considered to be health promoting, However, it is not verified that the modern vegetarian and vegan products are healthier than the ones they are meant to replace. Products based on vegetables are nowadays often produced with advanced techniques and can therefore differ substantially from the original vegetables. The epithelium in the gut is protected by a mucus layer that efficiently prevents bacteria to encounter the epithelium and even to translocate into the gut and the blood stream. In several inflammatory conditions such as e.g., inflammatory bowel disease (IBD) the barrier integrity is disrupted, and translocation will occur. Fibers are important for the gut microbiota enabling the production of short chain fatty acids (SCFA) that is necessary as nutrition for the epithelial cells, Fibers also promote the development of mucus. The aim of the present study is to evaluate components in the diet that is claimed to be health promoting even though they sometimes can be a hazard to your health. Both fibers and antinutrients can be found in these dietary regimens. The health effects of these products will be studied by analysis of the gut microbiota and the barrier integrity as markers of the health status. Gut microbiota will be analyzed with next generation sequencing and q-PCR (polymerase chain reaction). Diversity and the occurrence of different species will be determined. The barrier integrity will be estimated by analysis of bacterial DNA in blood and presence of live bacteria. The study consists of two different parts: 1a. 60 health volunteers are divided into two groups. One group consumes ordinary dairy based yogurt and the other a yogurt based on vegan products for four weeks to enable a change in the gut microbiota. At start and after four weeks fecal samples and questionnaires about the general health and gastrointestinal symptoms will be retrieved. It should be noted that the compounds offered can be bought in the ordinary shops. 1. b. The same design as above but with IBD patients instead. Their disease activity will be monitored by scoring sheets and regular blood tests as a part of their regular check-up. 2. a. The same design as in 1a but with comparison between a regular meat-based diet and a diet with vegetarian meat substitutes instead. 2b. The same design as I 2a but with IBD patients. Healthy volunteers will be invited wit advertisements. The IBD patients will be recruited at the out-patient clinic at the Dept of Gastroenterology at Skåne university hospital, Sweden. Before inclusion their disease activity will be monitored. The study is a prospective non-randomized intervention study including both men and women. Each individual will serve as their own control. The meals based on meat substitutes will be composed in cooperation with a dietitian. The estimated amount of yogurt is 200-250 gram/day, and the amount of meat is 150-200 gram/day.

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....

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.

The study aims to evaluate an egg-based H5N8 influenza vaccine up to 3 dose levels (low, medium, and high dose) given with or without adjuvant to see if the adjuvant improves vaccine effectiveness. The study will enroll healthy adults aged 18 years and over. Participants will receive 2 injections in their arm of either one of the 3 dose levels of the study vaccine (low, medium, or high dose) with the adjuvant or the unadjuvanted vaccine (high dose). Study duration per participant: approximately 14 months (including screening visit).

The main purpose of this study is to evaluate how well LY4178256 is tolerated and what side effects may occur in healthy participants. Blood tests will be performed to check how much LY4178256 gets into the bloodstream and how long it takes the body to eliminate it. For each participant, the study will last about 7 months and will include either 7 or 12 visits depending on the assigned treatment.

The main purpose of this study is to learn about safety, tolerability and how well the body processes two different eloralintide solutions. Participation in this study will last about 13 weeks, including screening, inpatient treatment, and follow-up.

This is a phase 1, single dose, randomized, open-label, parallel-group study to evaluate the pharmacokinetics (PK), safety, tolerability and immunogenicity of ZL-1503 and to explore its PD biomarkers following a single subcutaneous (SC) or intravenous (IV) administration in healthy volunteers.

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)....

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.

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.

This pilot study will test how Fermented Papaya Preparation (FPP) impacts overall TEWL of areas that commonly display diminished barrier function, such as the skin from face, arms, and hands. Areas of diminished barrier function are defined as those not visible to the eye but identified as areas of high transepidermal water loss (TEWL) as measured by a non-invasive pen-like device. A TEWL value of 20 or higher at a location would be considered high TEWL. Participants will attend 5 visits over 20 weeks, with 12-weeks of FPP treatment, and 8-weeks of follow-up.

The purpose of this study is to evaluate the safety and tolerability, pharmacokinetics and pharmacodynamics, pH and food effect, and preliminary efficacy of BMS-986470 in healthy volunteers and participants with sickle cell disease.

This first-in-human study will establish the human safety and radiation dosimetry of the system A amino acid transport substrate, (R)-3-\[F-18\]fluoro-2-methyl-2-(methylamino)propanoic acid (\[F-18\]MeFAMP), for positron emission tomography (PET) imaging of primary and metastatic brain tumors. This study will include 3 cohorts: healthy volunteers for whole body dosimetry estimates (n=6-8, Dosimetry Cohort), patients undergoing evaluation for recurrent high grade glioma after radiation therapy (n=10, high grade glioma (HGG) Cohort), and patients with brain metastases from extra-cranial solid tumors before and after radiation therapy (n=10, Metastasis Cohort). Exploratory assessment of the diagnostic accuracy of MeFAMP for distinguishing recurrent/progressive brain tumors from radiation-related treatment effects will also be performed for subsequent trial design. The study will complete accrual and safety assessment in the Dosimetry Cohort before recruiting for the HGG and Metastasis Cohorts.

Background: Alcohol use disorder (AUD) is a leading cause of disease and death worldwide. New treatments for AUD are needed. Dopamine, a chemical that carries signals between brain cells, is thought to play a role in alcohol addiction. Researchers want to learn how Suvorexant, a drug used to treat sleep disorders, affects dopamine receptors in the brain. Objective: To see how Suvorexant affects dopamine receptors in people with AUD and in healthy people. Eligibility: People aged 18 to 75 years seeking treatment for AUD. Healthy volunteers are also needed. Design: Participants with AUD will stay in the clinic for at least 10-28 days for alcohol detoxification. They will receive normal treatment for AUD. Suvorexant is a medicine used to treat sleep problem that is taken taken by mouth, once a day. Some participants will take the study drug. Others will take a placebo. The placebo looks like the study drug but does not contain any medicine. Participants will not know which they are taking. Participants will wear a device that looks like a wristwatch to track their movements during their clinic stay. Participants will have blood tests and 3 brain imaging scans before starting on the study drug: 2 positron emission tomography (PET) and 1 magnetic resonance imaging (MRI) scan. They will be injected with a radioactive tracer during each PET scan. Participants will have tests to assess their thinking, memory, and attention. They will have sleep studies. Imaging scans and other tests will be repeated at the end of the study. Healthy volunteers will have 1 MRI and 2 PET scans. They will have tests to assess of their thinking, memory, and attention. They will wear a wristwatch like movement monitor for 1 week. ...

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.

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.

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. ...

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)

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.

The purpose of this study is to evaluate novel KarX and KarT prototypes versus the KarXT and KarX-EC reference following single doses, to explore the effect of food after multiple doses of selected prototypes, and to evaluate alternative formulations of KarX and KarXT following single and multiple ascending doses in healthy adult participants.

This study examines how voluntary fast, deep breathing (hyperventilation) affects the way healthy adults perceive their own body. Participants wear a virtual-reality (VR) headset and see a virtual body; a glowing halo around it either pulses exactly in time with their own breathing or is time-shifted. During the study, breathing, heart activity, blood-oxygen level, the carbon-dioxide content of exhaled air, and brain activity (EEG, measured non-invasively from the scalp) are recorded continuously, and participants complete questionnaires about their experience. The aim is to understand whether and how altered breathing changes the interplay between what people see and what they feel inside their body, and thereby the sense of being located within one's own body. The study uses a 2×2 within-subjects design crossing Breathing (normal vs. hyperventilation) with Visual synchrony (synchronous vs. asynchronous), with the asynchronous and normal-breathing conditions serving as within-subject controls. No medication is administered and no medical device is being tested; the instruments used serve only for monitoring and measurement. Participation involves a screening visit (including a short, \~5-minute guided-hyperventilation tolerance test) and an experimental visit.