View clinical trials related to Healthy Volunteers.
Filter by:This study will test the safety of an experimental vaccine intended to prevent West Nile virus (WNV) infection and determine if it causes side effects. WNV symptoms may vary from fever and headache, to a polio-like syndrome with paralysis. Infection rarely results in death. The vaccine used in this study contains DNA that instructs the body to produce a small amount of a protein found in WNV. If the body creates resistance or immunity to these proteins, then the vaccine may protect against WNV. Study participants cannot get WNV from the vaccine. Healthy volunteers between 18 years and 50 years of age may be eligible for this study. Candidates are screened with a medical history, physical examination, and blood and urine tests, including a pregnancy test for women who can become pregnant. Patients undergo the following tests and procedures: - Vaccine injections: Vaccines are given as injections in the upper arm, using a needleless system called the Biojector 2000. The first injection is on study day 0, the second on day 28 (+/-) 7 days, and the third on day 56 (+/-) 7 days. There must be at least 21 days between injections. The pregnancy test for women of childbearing potential is repeated the day of each vaccine injection. - Diary card: Participants are given a 5-day diary card after each injection to record their temperature and any symptoms and side effects they may experience for up to 5 days after the injection. The diary cards are returned to the clinic at visits scheduled 2 weeks after each injection. Side effects and symptoms also must be reported immediately to a study nurse or doctor, and a clinic visit may be required for an examination. - Clinic visits: At day 0 and weeks 2, 4, 6, 8, 10, 12, 24 and 32, participants have a medical history, physical examination (if needed) and blood tests. Vital signs and weight are also recorded. Lymph nodes are examined at day 0 and weeks 2, 4, 6, 8, 10 and 12, and urine samples are collected at day 0 and weeks 2, 4, 6, 8 and 10. Some of the blood drawn during this study is used for genetic tests to see if different types of immune response to a vaccine are related to genetic differences in people.
This study will examine whether a new drug called acamprosate can be helpful for alcohol withdrawal, a result of drinking high amounts of alcohol for long periods of time. Alcohol withdrawal can cause various symptoms, including nausea or vomiting, anxiety or depression, tremor, high blood pressure, and others. During withdrawal, brain chemicals called neurotransmitters change, with some rising to abnormally high levels. These changes may contribute to alcohol craving, drinking relapse and impaired mental performance. This study will see if taking acamprosate for 4 weeks can lower the levels of neurotransmitters, such as glutamate, lessen withdrawal symptoms and decrease alcohol craving and brain damage associated with withdrawal. Healthy normal volunteers and alcohol-dependent patients between 21 and 65 years of age may be eligible for this study. Participants are admitted to the hospital for 28 days. They receive standard inpatient care for alcohol detoxification, including a medical history and physical examination, neurological evaluation, laboratory tests, nursing, nutrition, discharge planning and referrals for treatment of concomitant conditions, if needed. In addition, they are randomly assigned to take either two acamprosate or two placebo pills three times a day for 28 days and undergo the following tests and procedures: - Days 1-28: Drug treatment. Patients take acamprosate or placebo daily. Patients with severe withdrawal symptoms may also receive diazepam (Valium). Throughout their hospitalization, patients fill out questionnaires about their emotional state and personality and are interviewed by staff about their mental health, use of alcohol, cigarettes, and illicit drugs, employment, support systems and family and social relationships, and their legal status. - Days 2 and 3: Blood tests. Blood is tested for levels of the stress hormones cortisol and ACTH, which are released to excess during alcohol withdrawal. For this test, a heparin lock (thin, flexible plastic tube with a rubber stopper on the end) is placed in an arm vein for blood collections each day at 6 AM, 12 noon, 6 PM and 12 midnight. Patients rest in bed for 30 minutes before each collection. - Day 4: Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). These procedures are done at the same time. They use a strong magnetic field and radio waves to show structural and chemical changes in the brain. The patient lies on a table in a space enclosed by a metal cylinder (the scanner) for about 20 to 30 minutes during the test. - Day 5: Lumbar puncture (spinal tap). A local anesthetic is given to numb the area for the procedure. Then, a needle is inserted in the space between the bones in the lower back where the cerebrospinal fluid circulates below the spinal cord. A small amount of fluid is collected through the needle. - Days 5 and 6: Dexamethasone-corticotropin releasing factor (CRF) test. This test measures the effect of alcohol withdrawal on ACTH and cortisol. The patient takes a standard dose of the steroid dexamethasone at 11 PM on day 5. At noon the next day, they are given lunch and then stay in bed and rest. A plastic tube is put in an arm vein. A salt water solution is slowly infused through the catheter and a blood sample is withdrawn through it. At 3 p.m., the patient is given 100 micrograms of the hormone CRF. Repeated blood samples are obtained to measure ACTH and cortisol. - Days 23-27: All of the tests done on days 2-6 are repeated, except the MRI. MRS is repeated to measure neurotransmitters.
This study will explore the risks and causes of Parkinson's disease, a chronic progressive nervous system disorder. Patients typically have tremors, muscle weakness and a shuffling gait. Patients with Parkinson's disease, their relatives and healthy volunteers may be eligible for this study. Candidates must be 18 years of age or older. Patients whose parkinsonism is due to a secondary cause, such as infection or injury, and healthy volunteers who have a first degree family member (parent, grandparent, child, sibling) with Parkinson's disease are excluded from enrollment. Participants are asked about possible symptoms they may have and about their general health. They provide a blood sample to obtain DNA for genetic analysis to look for genetic differences that might be related to risks for Parkinson's disease. White blood cells may be treated in the laboratory to grow a cell line, which provides a source of substances in the blood without having to draw samples repeatedly.
This study will examine the effect of transcranial magnetic stimulation (TMS) on short-term memory in healthy adults. Healthy people use their brains to answer short-term memory questions in a different way than do patients with schizophrenia. Attention and memory deficits in schizophrenia patients significantly hamper their recovery and rehabilitation, yet there are no effective treatments for these impairments. TMS is a method of brain stimulation that may be able to change the electrical activity of the nerve cells of the brain and improve certain brain functions. This study will explore the effect of TMS on memory and perhaps discover brain processes that may be helpful in developing new ways to treat schizophrenia. Healthy volunteers between 18 and 55 years of age, excluding pregnant women, may be eligible for this study. Participants undergo the following tests and procedures: - Medical history, physical examination, blood tests, electrocardiogram (EKG), and urine pregnancy test for women of childbearing age. - Magnetic resonance imaging (MRI) and functional MRI (fMRI). These tests are done in participants who have not had structural and functional MRIs as participants in NIMH's 2-day schizophrenia study within 90 days of entering the current study. MRI is done to locate the place in the brain to simulate with TMS and fMRI is done to look at brain activity while the subject solves short-term memory tasks. Both tests are done at the same session. Before the scan, four vitamin E capsules are taped to the subject's scalp. After the capsules are in place, the subject lies on a stretcher that is moved into the scanner - a narrow cylinder with a strong magnetic field. During the scan, subjects are asked to do some simple tests, such as watching pictures on a screen or pressing buttons in response to numbers they were shown a few seconds earlier. Scanning may take up to 2 hours, but usually lasts between 45 and 90 minutes. - TMS. For this procedure, subjects receive either active TMS or a sham procedure (placebo) that imitates TMS but does not use real electrical stimulation. For TMS, an insulated wire coil is placed on the scalp and a brief electrical current is passed through it. This generates magnetic pulses that travel through the scalp and skull and cause small electrical currents in the cortex, or outer part of the brain. The stimulation may cause muscle twitching in the scalp or face and may also cause small movement of the limbs. During the procedure, electrodes are taped to the scalp to record the electrical activity of the brain while short-term memory is tested. Two tests make up a set. There are a total of six test sets; each set takes about 3 minutes. Five periods of electrical stimulation are delivered before each test set. Each period of stimulation lasts 5 seconds, followed by a 10-second rest period. The stimulation-rest intervals continue until five periods of TMS have been applied. For the memory test, subjects press a key on a computer keyboard as quickly and accurately as possible in a test of their ability to remember a string of numbers, or letters. - Questionnaires. At the beginning and end of the TMS session, participants fill out questionnaires that assess their mood, ability to concentrate, and level of anxiety.
This study has several parts. One part will examine the influence of factors such as personality and past experience on reactions to unpleasant stimuli. Others will examine the effect of personality and emotional and attentional states on learning and memory. When confronted with fearful or unpleasant events, people can develop fear of specific cues that were associated with these events as well as to the environmental context in which the events occurred via a process called classical conditioning. Classical conditioning has been used to model anxiety disorders, but the relationship between stress and anxiety and conditioned responses remains unclear. This study will examine the relationship between cued conditioning and context conditioning . This study will also explore the acquisition and retention of different types of motor, emotional, and cognitive associative processes during various tasks that range from mildly arousing to stressful.
This study will investigate mast cell precursors that circulate in the blood. In a group of diseases collectively known as mastocytosis, mast cells accumulate in abnormal amounts in the skin, lymphoid tissues, bone marrow, liver and spleen. Some forms of mastocytosis have a generally good prognosis; for others, the prognosis is poorer. There is no known cure for any form of the disease. A better understanding of mast cells and how they respond to certain substances may provide insights that will lead to effective treatments for mastocytosis. Patients with systemic mastocytosis and normal healthy volunteers between the ages of 20 and 60 may be eligible for this 8-day study. Participants will undergo the following procedures: - Day 1 Medical history, physical examination, and blood tests to assess general health status - Days 2 through 6 Daily injections under the skin of G-CSF a hormone that stimulates white blood cell production - Day 7 Leukapheresis a procedure for collecting large numbers of white blood cells. In leukapheresis, blood is drawn through a needle placed in an arm and channeled into a cell separator machine. The white cells are collected and the rest of the blood is returned to the body through a needle in the other arm. The procedure takes up to 3 hours. - Days 7 and 8 Blood draw (about 1 teaspoon) to monitor white blood cell counts.
This study is designed to provide bone marrow and/or blood cells for other research studies. Patients participating in this study will be asked to provide small amounts of medical information and undergo a limited physical examination designed to detect the presence of any obvious blood disease. A blood and bone marrow sample will be obtained to verify that the patient has normal blood cell production. Researchers plan to obtain bone marrow samples to be used in laboratory studies directed toward understanding the formation of blood cells. Bone marrow samples will be taken from the hip bone of patients and healthy volunteers. These samples are valuable to many research studies within the Hematology Branch of the National Heart, Lung, and Blood Institute, including studies of normal and abnormal production of blood cells, the viral causes of blood diseases, and the role of the immune system in bone marrow failure and related conditions....
Patients with lung disease experiencing difficulty breathing can be treated with oxygen therapy. This involves the delivery of "extra" oxygen by a face-mask or through small tubes placed in the nose called nasal prongs. This extra oxygen can have concentrations as high as 100% pure oxygen. The concentration of oxygen in normal air is only 21%. The high concentration of oxygen can help to provide enough oxygen for all of the organs in the body. Unfortunately, breathing 100% oxygen for long periods of time can cause changes in the lungs, which are potentially harmful. Researchers believe that by lowering the concentration of oxygen therapy to 40% patients can receive it for longer periods of time without the risk of side effects. This study is designed to evaluate the effects of oxygen therapy at 100% and 40% for 12 18 hours on the lungs of normal volunteers. Results of this study will help to determine if levels of oxygen therapy currently accepted as being "safe" may actually be damaging to the lungs.
This study evaluates the effects of estrogen and progesterone on mood, the stress response, and brain function in healthy women. The purpose of this study is to evaluate how low levels of estrogen and progesterone (that occur during treatment with leuprolide acetate) compare to menstrual cycle levels of estrogen and progesterone (given during individual months of hormone add-back) on a variety of physiologic measures (brain imaging, stress testing, etc.) in healthy volunteer women without PMS. This study will investigate effects of reproductive hormones by temporarily stopping the menstrual cycle with leuprolide acetate and then giving, in sequence, the menstrual cycle hormones progesterone and estrogen. Tests (such as brain imaging or stress testing, etc.) will be performed during the different hormonal conditions (low estrogen and progesterone, progesterone add-back, estrogen add-back). The results of these studies will be compared between women without PMS and women with PMS (see also protocol 90-M-0088). At study entry, participants will undergo a physical examination. Blood, urine, and pregnancy tests will be performed. Cognitive functioning and stress response will be evaluated during the study along with brain imaging and genetic studies.
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.