View clinical trials related to Healthy Volunteers.
Filter by:Chronic obstructive pulmonary disease (COPD for short) involves inflammation inside the air passages of the lungs. This inflammation might be partly responsible for the shortness of breath, cough and susceptibility to chest infections that form part of COPD. Inflammation is caused, in part, by white blood cells that are attracted from the blood into the air passages. Once inside the air passages, the white blood cells may change (or 'differentiate') and release substances that produce inflammation and attract more white cells. The hypothesis is that the lifespan of these cells may also be prolonged such that they produce more inflammatory mediators and in turn perpetuate inflammation. The cycle of inflammation may damage the lungs, so we want to see what mediators are released by white blood cells and determine if we can inhibit this effect with existing and new drugs. We would also like to see the effect of these drugs on the life-span and function of white blood cells. We will compare the behaviour and characteristics of white cells with those from healthy smokers and healthy non-smokers to find out if there is anything different about cells from COPD patients.
The purpose of this study is to explore the possible cognitive effects of darifenacin modified release and long-acting oxybutynin.
The ability to metabolize drugs varies greatly among individuals. Major fraction of this variability lies in genetic polymorphisms of genes encoding for enzymes responsible for both phase I and phase II reactions. The purpose of this study ws to evaluate the phenotypic activity and the frequency of genetic polymorphisms in different phase II and phase I enzymes among various populations residing in Israel.
Microvascular dysfunctions are critical events in several diseases including diabetes. This study will develop a methodology for microvascular investigation in human skin. The purpose of the study is to investigate the physiological response of the cutaneous microcirculation to physical, thermal, mechanical or chemical stimulations.
This study will collect blood plasma and white blood cells from individuals using a procedure called apheresis. Apheresis is a method of collecting larger quantities of certain blood components that can safely be collected through a simple blood draw. The blood components will be used in laboratory research studies. Patients 18 years of age and older who are currently enrolled in a NIH clinical research protocol may participate in this study. Relatives of patients and normal healthy volunteers will also be enrolled. Individuals will undergo one of the following two apheresis procedures: - Automated pheresis Blood is drawn through a needle placed in an arm vein and circulated through a cell separator machine. The plasma (liquid part of the blood) and white cells are extracted, and the red cells are re-infused into the donor through the same needle or a needle in the other arm. An anticoagulant (medication to prevent blood from clotting) is usually added to the blood while in the machine to prevent it from clotting during processing. - Manual pheresis One unit (1 pint) of blood is drawn through a needle placed in an arm vein, similar to donating a pint of whole blood. The red blood cells, with or without plasma, are separated from the rest of the blood and returned to the donor through the same needle. Manual pheresis will be done only when a person s estimated total blood volume or red cell count is too low to safely permit removal of blood through a pheresis machine. An adult small in size or markedly anemic, for example, may fall into this category. Some of the blood collected through apheresis may be stored for future studies of HIV disease and immune function and for HLA testing, a genetic test of markers of the immune system. Some of the blood may be used to screen for different types of viral liver infections, such as hepatitis A, B, C, D, E, F, or G. ...
The purpose of this study is to determine the levels of testosterone and/or estradiol at which changes in bone turnover, body composition, strength, sexual function etc. begin to occur in older men. This information may help determine when to intervene with hormone replacement therapy in aging men.
This study will examine abnormalities in mitochondria (energy-producing machinery of cells) and in genes related to mitochondria in the blood cells, muscle, and fat of HIV-positive patients who are taking nucleoside reverse transcriptase inhibitors (NRTIs) and in patients not currently taking HIV medications, and compare the results to healthy volunteers. Many patients with HIV infection take NRTIs to help control the infection. These medications may damage cell mitochondria, possibly causing side effects such as fatigue. This study will explore the relationship between changes in mitochondria and related genes and patient reports of energy level, mood and quality of life. Healthy volunteers and HIV-infected patients between 18 and 55 years of age may be eligible for this study. Healthy volunteers must test negative for the HIV antibody. HIV-positive patients must have been diagnosed positive for at least 1 year. Patients who are taking antiretroviral therapy must have been taking the same drug regimen (with at least two NTRIs and no protease inhibitors) for at least 3 months. HIV positive patients not taking antiretroviral medication must not have had antiretroviral therapy for at least 1 year. Candidates are screened with a medical history, brief physical examination, blood and urine tests, and questionnaires related to mood and energy. Qualified volunteers will undergo the following procedures during three or four study visits: Visit 1 Complete history and physical examination, blood tests, and questionnaires about energy level, mood, and quality of life. Visit 2 Muscle and fat biopsy: Before the biopsy, blood is drawn to check blood counts and to test for pregnancy in women who can become pregnant. The biopsy is done on an outpatient basis in the operating room. The site of the biopsy (an area on the upper arm or upper leg) is numbed with an injection under the skin. A 1-inch incision is made over the muscle to be biopsied and a small sample of muscle tissue and small sample of fat are removed. The incision is then closed and bandaged. Following the biopsy, you will be monitored for about 4 hours in the clinic. Strenuous physical activity should be restricted in the week following biopsy to allow healing. Visit 3 Examination of biopsy site and possible apheresis: The biopsy site is examined for healing. Apheresis may be scheduled for this visit or for an extra visit between the biopsy and the final visit. This procedure for obtaining white blood cells for study is optional. For apheresis, blood is withdrawn from a needle placed in a vein in the arm and the white cells are separated from the rest of the blood. The white cells are extracted and the red cells and plasma are then returned to the body through a second needle.
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 examine how nitrite infusions affect exercise tolerance (how much a person can exercise before having to stop). Exercise ability is limited by how fast oxygen can be delivered to the body and how fast the body can produce energy. Both of these processes are affected by nitric oxide (NO), a gas produced by cells that line blood vessels. NO is important in regulating blood vessel dilation, and consequently, blood flow. Nitrite may act as a storehouse for nitric oxide and be able to improve exercise tolerance. Healthy normal volunteers between 21 and 45 years of age who can use an exercise bicycle may be eligible for this study. Candidates are screened with a medical history, physical examination, electrocardiogram, breathing tests, blood tests, and a pregnancy test for women who are able to bear children. Pregnant women are excluded from the study. The screening session includes practice exercise on the bicycle. Participants exercise on a stationery exercise bicycle for about 30 minutes on each of two study days. During the test, they breathe in and out of a mouthpiece that allows inhaled and exhaled respiratory gases to be measured. Before subjects begin to exercise, a small tube is placed in the artery of their forearm inside the elbow. A longer tube called a central line is placed in a deeper vein in the neck after the area has been numbed. A thinner tube, called a pulmonary artery catheter, is placed through the central line and advanced into the chambers of the heart, through the heart valve, and into the lung artery. This catheter measures various pressures directly in the heart and lungs. Blood samples are drawn through the catheter also, to avoid the need for multiple needle sticks. Another tube is placed in the vein of the other arm to deliver medications. Thirty minutes after all the tubes are placed, a blood sample is drawn for baseline measurements. Then, either saline (sterile salt water) or nitrite is injected into the tube in the arm vein. Thirty minutes after the injection, the subject starts exercising on the bicycle. The work setting on the bicycle is increased every minute, and the subject pedals until he or she is too tired to continue. During the test, a small blood sample is collected every 2 minutes. Heart rate, blood pressure, and heart rhythms are continuously monitored. After the test on the first day, participants are admitted to the hospital to rest for the remainder of the afternoon and evening. The tubes are kept in place for the following morning, when the procedure is repeated exactly as before, except that subjects who received saline the first day are given nitrite the second day, and vice versa.