View clinical trials related to Healthy Volunteers.
Filter by:The purpose of this investigation is to develop improved magnetic resonance imaging (MRI) techniques and hardware for studying brain function. MRI is a diagnostic tool that provides information about brain chemistry and physiology. This study will evaluate new MRI methods for monitoring blood flow to regions of the brain in response to simple tasks. The MRI machine used in this study is more powerful than those in most hospitals, permitting a higher visual resolution. Normal healthy volunteers over 18 years old may be eligible for this study. Candidates will be screened with a medical history and questionnaire, and a neurological examination. Study participants will have a yearly MRI scan. For this procedure, the subject lies on a stretcher that is moved into a donut-shaped machine with a strong magnetic field. A lightweight circular or rectangular coil a device that improves the quality of the images may be placed on the head. The scan time varies from 20 minutes to 3 hours; most scans last between 45 and 90 minutes. During the scan, the subject may perform simple tasks, such as listening to tapes, tapping a finger, moving a hand, watching a screen, or smelling a fragrance. More complex tasks may require thinking about tones or pictures and responding to them by pressing buttons. Information from this study will be used to develop better imaging methods that will, in turn, permit a greater understanding of normal and abnormal brain behaviors.
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.
Magnetic resonance is an imaging technique that uses magnetic fields and radio waves to create images of the body. The technology used in magnetic resonance imaging continues to improve. Advancements in magnetic resonance imaging (MRI) requires researchers to study new techniques in normal volunteers in order to understand how to use them in patients with diseases. In this study researchers plan to do a variety of diagnostic tests including magnetic resonance imaging on normal volunteers. The studies may involve injections of contrast media, substances injected into the blood of participant that improves the image created by the MRI scanner. The study is not expected to benefit the participants. However, information gathered from the study may be used to improve diagnostic techniques and develop new research studies.
This study will examine how quickly white blood cells called CD4 lymphocytes replicate (divide) and how long they live in both HIV-infected and non-infected people by measuring how quickly the genetic material (DNA) of cells is replicated. To do this, participants will receive infusions of glucose, a non-radioactive form of a type of sugar. Cells normally use glucose to make various products needed for cell growth and replication, including cell DNA. Measuring how much glucose cells incorporate into their DNA can provide important information about cell replication. This rate of incorporation will be examined and compared in HIV-infected people and in healthy, normal volunteers. HIV-infected patients and non-infected healthy volunteers 18 years of age and older may be eligible for this study. Candidates will be screened with a medical history, physical examination, chest X-ray, electrocardiogram (EKG) and blood tests. Participants will be given a continuous infusion of glucose at a dose of up to 60 grams (about 2 ounces) per day for up to 5 days. The glucose will be delivered through a catheter (thin plastic tube) placed in an arm vein. Blood samples will be collected as often as daily in the first week following the infusion and then from twice a week to once a month for up to 4 years. Alternatively, patients may undergo leukapheresis a procedure for collecting quantities of lymphocytes up to 10 times during the first month after the infusion, and possibly later as well, but no more often than once every 2 weeks. For this procedure, whole blood is collected through a needle in an arm vein. The blood circulates through a machine that separates it into its components. The white cells are removed and the rest of the blood is returned to the body either through the same needle or through a second needle in the other arm. Participants may be asked to receive up to four glucose infusions. There will be at least a 2-week interval between infusions. Participants who have more than three leukapheresis procedures within 3 weeks will have at least 6 weeks between infusions. Participants will be followed periodically in the outpatient clinic for evaluation and tests. This study may provide a better understanding of how HIV causes disease and progressive weakening of the immune system and how therapies affect immunity.
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....
This study allows the evaluation of subjects in order to determine their ability to safely participate in other active research studies. After subjects complete the screening process, they will be offered the opportunity to participate in an active research study, or if no appropriate studies are available information and recommendations will be provided for other treatment options.
Background: -This protocol is concerned with the acquisition of blood, skin, or mucosal samples from healthy volunteers or patients with selected skin diseases to support the basic science and clinical research activities of the Dermatology Branch and other intramural Laboratories and Branches at the NIH Clinical Research Center. Objectives: (Primary) -To allow collection of blood, skin, or mucosal samples from healthy volunteers or patients with selected skin or systemic diseases as needed to support the research activities of our Branch and other Laboratories and Branches. Eligibility: - Healthy individuals (including employees and other patients) and patients with selected skin or other diseases, including individuals of both genders and all racial/ethnic groups. - Patient volunteers must be willing to undergo blood drawing and/or skin/mucosal biopsies. Design: -This is dependent upon the particular investigation for which these samples are needed....
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.
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 protocol is a screening and natural history protocol, which allows for evaluation of patients and families where neurological conditions are present for enrollment into other studies and will also be used to screen healthy volunteers to create a pool of potential future HV matches for HMCS protocols. Through diagnostic evaluations, data will be collected for research use in this study.