View clinical trials related to Sickle Cell Anemia.
Filter by:The purpose of this research is to evaluate the effects of L-glutamine as a therapy for sickle cell anemia and sickle ß0-thalassemia. as evaluated by the number of occurrences of sickle cell crises.
This study will explore what may cause people with sickle cell anemia to have heart problems and an increased risk of sudden death. People 18 years of age and older with sickle cell anemia may be eligible for this study. Candidates are screened with a medical history and physical examination, electrocardiogram (EKG), echocardiogram (heart ultrasound), and blood tests. Participants undergo the following tests and procedures: - Holter monitoring: The patient wears a small, battery-operated device to record heart rate and rhythm over 24 to 48 hours. - QRST surface mapping: An EKG using 64 electrodes is done at rest and during exercise to provide a detailed look at the heart and its conduction system. - Chest x-rays are taken to examine the lungs. - Bicycle exercise echocardiography test: Blood pressure, pulse, heart rhythm and oxygen use are monitored while the patient exercises on a stationary bicycle. Ultrasound pictures are also obtained during the exercise. - Echocardiogram: A heart ultrasound is done to check how well the heart is pumping blood. - Pulmonary artery catheterization: A catheter (plastic tube) is inserted into a vein and advanced to the chambers of the heart, through the heart valve and into the lung artery. The pressures in the heart and lung blood vessels are measured while the patient is resting and during exercise, with the bed tilted up and down, and after giving 500 mls of fluid into a vein. - Blood tests are done to measure a hormone called brain natriuretic peptide, which can increase with the development of heart failure, and nitrite, a substance that can affect blood vessel dilation. Some blood is stored to test for inflammatory markers and for possible future gene and protein analysis. - Cardiac magnetic resonance imaging (cMRI): The patient lies in a donut-shaped magnet while pictures of the heart are obtained using a magnetic field and radio waves. Earplugs are worn to muffle the loud sounds that occur with electrical switching of the magnetic fields. A contrast agent called gadolinium may be injected to enhance the quality of the images. - Invasive electrocardiographic (reveal) monitoring: This procedure permits study of the heart rhythms over a long time period. A small device is placed just under the skin on the left side of the chest. It can be left in for up to 14 months to monitor the heartbeat continuously during this time.
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.
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.
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.
ICA-17043 is being developed for the chronic treatment of patients with sickle cell disease (SCD) in both adults and children. ICA-17043 is a potent and specific inhibitor of a channel in human red blood cells (RBCs) that blocks RBC dehydration. ICA-17043 is expected to inhibit RBC dehydration and thus should prevent or delay the sickling process. By reducing sickled cells, an improvement in anemia, a reduction in painful crises, and ultimately, less end-organ disease is anticipated.
The major goal of this study is to determine the risks and benefits of bone marrow transplants in patients with severe thalassemia or sickle cell disease. Participation in this project will be for two years.
The major goal of this study is to determine the risks and benefits of stem cell transplants in combination with a newer, less toxic conditioning chemotherapy treatment in patients with severe sickle cell disease (SCD) or sickle hemoglobin variants (hemoglobin SC or hemoglobin SB0/+), or homozygous b0/+ thalassemia or severe B0/+ thalassemia variants. Participation in this project will be for one year, with follow up evaluations done every 6 months thereafter for 10 years or until participants are 18 years old.
This study will test whether inhaling nitric oxide (NO) gas mixed with room air can improve pulmonary hypertension (high blood pressure in the lungs) in patients with sickle cell anemia. Patients with sickle cell disease 18 years of age or older may be eligible to participate in one or more parts of this three-stage study, as follows: Stage 1 Patients undergo the following tests to determine the cause of their pulmonary hypertension: blood tests; echocardiogram (heart ultrasound); asthma test; oxygen breathing study with measurement of arterial blood oxygen levels; chest X-ray; lung scans; MRI of the heart; 6-minute walk test; night-time oxygen measurement while sleeping; and exercise studies. Stage 2 Patients have a detailed MRI evaluation of the heart and are admitted to the NIH Clinical Center intensive care unit (ICU) for the following test: A plastic tube is placed in a vein in the patient's arm and another tube is placed in a deeper neck or leg vein. A third tube is inserted through the vein into the heart and the lung artery to measure blood pressures in the heart and lungs directly. Following baseline measurements, three medications (inhaled oxygen, infused prostaglandin, and inhaled NO) are delivered for 2 hours each, separated by a 30-minute washout period. A small blood sample is drawn during the NO administration. Patients who cannot be treated with nitric oxide or for whom the treatment does not work may receive monthly exchange transfusions for 3 months. For this procedure, 3 to 5 five units of the patient's blood is removed and replaced with 3 to 5 units that do not have sickle hemoglobin. Some patients who do not respond to NO or exchange transfusions may receive an alternative therapy, such as oxygen, prostacyclin, L-arginine, bosentan or sidenafil. Stage 3 Patients remain in the ICU with catheters in place for another 24 hours. During this time they breathe NO. Lung pressures are measured every 4 hours and blood is drawn every 8 hours. They then stay in the hospital 1 more day for observation. Patients then breathe nitric oxide continuously for 2 months using a tank of gas that delivers the NO through tubes placed in the nose. They may do this at home on an outpatient basis or may remain in the hospital for the 2 months. Patients have an echocardiogram and blood tests every week and do a 6-minute walk test every 2 weeks....
The purpose of this study is to determine how often people with sickle cell anemia develop pulmonary hypertension a serious disease in which blood pressure in the artery to the lungs is elevated. Men and women 18 years of age and older with sickle cell anemia may be eligible for this study. Participants will undergo an evaluation at Howard University s Comprehensive Sickle Cell Center in Washington, D.C. or at the National Institutes of Health in Bethesda, Maryland. It will include the following: - medical history - physical examination - blood collection (no more than 50 ml., or about 1/3 cup) to confirm the diagnosis of sickle cell anemia, sickle cell trait or beta-thalassemia (Some blood will be stored for future research testing on sickle cell anemia.) - echocardiogram (ultrasound test of the heart) to check the pumping action of the heart and the rate at which blood travels through the tricuspid valve. Following this evaluation, a study nurse will contact participants twice a month for 2 months and then once every 3 months for the next 3 years for a telephone interview. The interview will include questions about general health and recent health-related events, such as hospitalizations or emergency room visits.