View clinical trials related to Anemia, Sickle Cell.
Filter by:This study examines ways in which nitric oxide (NO), an important molecule that controls how blood flows through the body's vessels, might be restored with a compound called sodium nitrite. It is hoped that the result will reverse the effect of decreased flow of blood due to sickled cells-that is, cells that have changed into the shape of a crescent or sickle. Sickle cell disease is the most common genetic disease affecting African Americans. About 8% of that population has the sickle cell trait. The changed cells can become attached to blood vessels, decreasing blood flow to vital organs. There can be the loss of needed proteins, including hemoglobin, that deliver oxygen throughout the body. Adults at least 18 years of age who have the SS form of sickle cell disease or S-beta-thalassemia, are in either a steady state or crisis, give informed and written consent for participation, and have had a negative pregnancy test may be eligible for this study. Adults with any other disease that puts them at risk for reduced circulation are not eligible. Women who are breastfeeding are not eligible. Participants will undergo a medical history, including family medical history, and a detailed physical evaluation, to take about 1 hour. There will be a collection of blood; echocardiogram, which involves taking a picture of the heart and its four chambers; and measurement of exhaled carbon monoxide, carbon dioxide, and NO. A procedure called orthogonal polarization spectral imaging will be performed. A small object the size of a Popsicle stick will be placed under the tongue or on a fingertip. This procedure presents a picture of blood flow and how the red blood cells appear as they circulate through blood vessels. The study will be conducted in the Vascular Laboratory/Cardiovascular Floor or Intensive Care and will last about 4 hours. During the study, patients will lie in an adjustable reclining bed and chair. Small tubes will be placed in the artery and vein of the forearm at the inside of the elbow. A small pressure cuff will be applied to the wrist and a larger one to the upper arm. Both cuffs will be inflated with air. A strain gauge, resembling a rubber band, will go around the widest part of the forearm. When the pressure cuffs fill with air, blood will flow into the arm, and information from the strain gauge will be recorded. Between administrations of each medicine, there will be 30-minute rests. Normal saline will be put into the small tube in the artery. Measurements of the blood flow in the forearm will be taken, and a small blood sample will be taken to measure blood counts, proteins, and other natural body chemicals. Then a medicine called sodium nitroprusside, which causes blood vessels to expand and increase blood flow, will be placed into the forearm. It will be given at three different doses for 3 minutes each, with measurements recorded after each dose. Then a medicine called L-NMMA will be placed into the forearm. L-NMMA generally decreases local blood flow by preventing nitric oxide from being produced in the cells lining the blood vessels. It will be given at two different doses for 5 minutes each, with blood flow measured after each dose. Next, nitrite will be placed in the forearm at three different doses for 5 minutes each. Before and after nitrite is given, the researchers will measure the amount of the NO, carbon monoxide, and carbon dioxide that the patients breathe out. Then the procedure for administering normal saline, sodium nitroprusside, and L-NMMA will be repeated, as will a blood test. This study will not have a direct benefit for participants. However, it is hoped that the information gained from the study will help to develop treatment options for patients with sickle cell disease.
This study will examine whether nitric oxide (NO) gas can reduce the time it takes for pain to go away in patients who are in sickle cell crisis. NO is important in regulating blood vessel dilation, and consequently, blood flow. The gas is continuously produced by cells that line the blood vessels. It is also transported from the lungs by hemoglobin in red blood cells. Patients 10 years of age or older with sickle cell disease (known SS, S-beta-thalassemia or other blood problems causing sickle cell disease) may be eligible for this study. Patients whose disease is due to hemoglobin (Hgb) SC are excluded. Candidates are screened with blood tests and a chest x-ray to look at the lungs and heart. Participants are admitted to the hospital in a pain crisis. They are evaluated and then randomly assigned to receive one of two treatments: 1) standard treatment plus NO, or 2) standard treatment plus placebo. The placebo used in this study is nitrogen, a gas that makes up most of the air we breathe and is not known to help in sickle cell disease. For the first 8 hours of the study, patients receive placebo or NO through a facemask. The mask may be taken off for 5 minutes every hour and for not more than 20 minutes to eat a meal. After the first 8 hours, the gas is delivered through a nasal cannula (small plastic tubing that rests under the nose) that may be taken off only while showering or using the restroom. Patients are questioned about the severity of their pain when they start the study and then every few hours while they are in the hospital. Their vital signs (temperature, breathing rate, and blood pressure) and medicines are checked. Patients will breathe the gas for a maximum of 3 days, but will stay hospitalized until the patient feels well enough to go home. Patients are followed up about 1 month after starting the study by a return visit to the hospital or by a phone call.
This study is not a treatment protocol and no experimental treatments are involved. Study participants may be seen as needed for clinical, translational and basic research studies, or as medically indicated. Subjects will receive their general medical care outside the NIH and will be seen at our clinic or at CNHS with varying frequency. Subjects may be seen for multiple visits. Subjects may be asked to return for additional testing as needed. Clinical care for patients with sickle cell disease will be provided as appropriate through the Sickle Cell Clinic and the inpatient clinical center.
This study will examine the effects of oral atorvastatin on the linings of blood vessels in patients with sickle cell disease, plus the agent's effect on blood markers of inflammation and blood vessel function. Sickle cell disease is a recessive genetic disorder and the most common genetic disease affecting African Americans. Inherited are abnormal genes that make hemoglobin, the substance within red blood cells that carries oxygen from the lungs to the body. In the disease, sickle hemoglobin leads to rigidity or hardness of the red cells, causing obstruction in small blood vessels, inflammation, and injury to organs when the flow of blood to them is blocked. Some medications already prescribed for other diseases, such as atorvastatin, which is used for lowering cholesterol levels, can improve blood flow. Patients 18 to 65 years of age who have sickle cell disease, who have not had an acute pain episode within the previous week, and who are not pregnant or lactating may be eligible for this study. They will undergo a complete medical history; physical examination; baseline blood tests; and echocardiogram, in which an ultrasound wand is placed against the chest wall to get images inside the heart and blood vessels. In addition, patients will have blood flow studies. During the procedure, they will lie in an adjustable reclining chair for 5 to 6 hours. There will be 20- to 30-minute rests between specific activities and blood samples will be drawn intermittently for testing. Small tubes will be placed in the artery of the forearm at the inside of the elbow. Normal saline will be infused into one tube. A small pressure cuff will be applied to the wrist and a larger cuff to the upper arm. Both cuffs will be attached to an inflation device. A device like a rubber band, a strain gauge, will be placed around the widest part of the forearm. When the pressure cuffs are inflated, blood will flow into the arm, stretching the gauge proportion to blood flow, and information will be recorded. Then light reflected from the patients' hand and the blood flow in the forearm will be measured. Activity of the genes in the white blood cells will be measured as well. Small amounts of sodium nitroprusside, widely used to reduce blood pressure in people with dangerously high blood pressure, will be injected and blood flow will be measured. Later, small amounts of acetylcholine will be injected. It usually causes blood vessels to expand. After that, small amounts of L-NMMA will be injected. It usually decreases local blood flow by blocking the production of nitric oxide in the cells lining the arm's blood vessels. Then acetylcholine combined with L-NMMA will be injected. After that, oxypurinol, an agent taken by many patients to prevent gout, will be injected. The procedures will be repeated, with oxypurinol given along with each of the agents, and the measurement of blood flow in the forearm will be measured after each drug combination. Afterward, patients will be treated for 4 weeks at home with oral atorvastatin. They will be asked to visit the Clinical Center every 2 weeks for collection of blood samples and an examination. After 4 weeks of taking atorvastatin orally, they will be asked to return to repeat the blood flow studies, but only the first half will be conducted. The part using oxypurinol will not be needed. Regarding some of the blood samples collected during the study, there will be an examination of the genes found in the white blood cells. Specific attention will go to those genes that make proteins for cell-to-cell interaction and inflammation, plus those that cause blood cells to stick to the lining of blood vessels.
The goal of this study is to determine the effectiveness of blood transfusion therapy for prevention of silent cerebral infarct (stroke) in children with sickle cell anemia.
The purpose of this study is to determine if the new orally active iron chelator, ICL670, is as safe as deferoxamine in preventing accumulation of iron in the body while a patient is undergoing repeated blood transfusions.
The purpose of this study is to compare the effects of in-home, family-administered massage and in-home relaxation training on measures of physical status and health care utilization in a sample of African American adolescents age 15 years and older and adults with chronic pain associated with sickle cell disease who have been randomly assigned to six sessions of either family-administered massage or progressive muscle relaxation training.
People with severe congenital anemias, such as sickle cell anemia and beta-thalassemia, have been cured with bone marrow transplantation (BMT). The procedure, however, is limited to children younger than the age of 16 because the risks are lower for children than for adults. The purpose of this study is to explore the use of a BMT regimen that, instead of chemotherapy, uses a low dose of radiation, combined with two immunosuppressive drugs. This type BMT procedure is described as nonmyeloablative, meaning that it does not destroy the patient s bone marrow. It is hoped that this type of BMT will be safe for patients normally excluded from the procedure because of their age and other reasons. To participate in this study, patients must be between the ages of 18 and 65 and have a sibling who is a well-matched stem-cell donor. Beyond the standard BMT protocol, study participants will undergo additional procedures. The donor will receive G-CSF by injection for five days; then his or her stem cells will be collected and frozen one month prior to BMT. Approximately one month later, the patient will be given two immune-suppressing drugs, Campath 1-H and Sirolimus, as well as a single low dose of total body irradiation and then the cells from the donor will be infused. Prior to their participation in this study, patients will undergo the following evaluations: a physical exam, blood work, breathing tests, heart-function tests, chest and sinus x-rays, and bone-marrow sampling. ...
To use transcranial Doppler (TCD) ultrasound to detect stroke risk in children with sickle cell disease.
Patients with sickle cell disease have abnormal hemoglobin (the protein in red blood cells that carries oxygen to the body). This abnormality causes red blood cells to take on a sickle shape, producing disease symptoms. Fetal hemoglobin, a type of hemoglobin present in fetuses and babies, can prevent red cells from sickling. The drug hydroxyurea increases fetal hemoglobin production in patients with sickle cell disease by making a molecule called nitric oxide. The drugs L-arginine and Sildenafil (Viagra) increase the amount or the effect of nitric oxide. This study will evaluate: - The safety of giving L-arginine or Sildenafil together with hydroxyurea in patients with sickle cell disease; - The effectiveness of L-arginine plus hydroxyurea or Sildenafil plus hydroxyurea in increasing fetal hemoglobin in patients with sickle cell disease; and - The effectiveness of L-arginine plus hydroxyurea or Sildenafil and hydroxyurea in lowering blood pressure in the lungs of patients with sickle cell disease. (Pulmonary blood pressure is elevated in about one-third of patients with sickle cell disease, and this condition increases the risk of dying from the disease.) Patients with hemoglobin S-only, S-beta-thalassemia, or other sickle cell disease genotype may be eligible for this study. Before starting treatment, patients will have a complete medical history and physical examination. All patients will take hydroxyurea once a day every day by mouth for at least 2 months. They will be admitted to the NIH Clinical Center to take their first dose of hydroxyurea, and will have blood drawn through a catheter (plastic tube placed in a vein) every hour for 6 hours for tests to determine nitric oxide levels. After discharge, they will return to the clinic once every 2 weeks to check for treatment side effects and for blood tests to monitor hemoglobin and fetal hemoglobin levels. After fetal hemoglobin levels have been stable for 2 months, patients will be admitted to the Clinical Center for their first dose of L-arginine (for men) or Sildenafil (for women). Again, blood samples will be collected through a catheter once an hour for 6 hours. If there are no complications, patients will be discharged and will continue taking hydroxyurea once a day and L-arginine or Sildenafil three times a day for at least 3 months until fetal hemoglobin levels have been stable for at least 2 months. Patients will return to the clinic for blood tests every week for 2 weeks and then every 2 weeks to monitor hemoglobin and fetal hemoglobin levels and to check for treatment side effects. Patients will have eye examinations before and during treatment. Some patients with sickle cell disease develop abnormalities in the blood vessels of the eye. Also, Sildenafil can cause temporary changes in color vision. Rarely, more serious eye problems can occur, such as bleeding from the eye blood vessels or damage to the retina a layer of tissue that lines the back of the eye. Patients will also have an echocardiogram (ultrasound of the heart) before beginning treatment, after hydroxyurea treatment, and after 1 and 3 months of combined treatment with hydroxyurea and L-arginine or Sildenafil to help measure blood pressure in the lungs. Patients who develop complications from L-arginine or Sildenafil may continue in the study on hydroxyurea alone. Patients whose fetal hemoglobin levels increase with the combination therapy of hydroxyurea and L-arginine or Sildenafil may continue to take them.