View clinical trials related to Anemia, Sickle Cell.
Filter by:This study will develop a national cord blood bank for siblings of patients with hemoglobinopathies and thalassemia.
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....
This study will determine the best ways to collect, process and store umbilical cord blood from babies with sickle cell disease, sickle cell trait and unaffected babies. Sickle cell disease is an abnormality of the hemoglobin in red blood cells that causes the cells to change shape and clump together, preventing their normal flow in the bloodstream. This impairs blood flow to various organs, and the resulting oxygen deprivation causes organ damage. Cord blood is rich in stem cells (cells produced in the bone marrow that mature to different types of blood cells), which may prove useful in new sickle cell therapies. However, cord blood from babies with sickle cell trait, sickle cell disease and normal babies may act differently under laboratory conditions, so it is important to learn how best to work with blood from all three groups of babies for future use in possible treatments. Pregnant women between 18 and 45 years of age who are at risk of having an infant with sickle cell disease and normal volunteers who are pregnant and not at risk for this disease may be eligible for this study. Potential participants will be counseled about donating her infant s blood in order to make an informed choice. All women who participate in the study will provide a medical history and have blood collected from the umbilical cord and placenta (afterbirth) after the baby s delivery. The blood will be tested for various infectious diseases, processed, frozen and stored for research purposes. In addition, blood from women with babies at risk for sickle cell disease will be tested for the presence of the sickle cell gene, tissue typed, and used for research as follows: - Sickle cell disease - If cord blood tests show the baby has sickle cell disease, the blood will be frozen for an indefinite period of time for possible use in future treatment of the child. This treatment could include stem cell transplantation or gene therapy, treatments are not currently considered routine for sickle cell disease. - Sickle cell trait or normal hemoglobin - If cord blood tests show the baby has sickle cell trait or is unaffected, the blood will be processed and stored for up to 3 years, during which time it may possibly be used to treat a currently living or future sibling with sickle cell disease. After 3 years, the participant may agree to either have the blood discarded, given to research or moved to another facility for continued storage at the participant s expense, if there is a storage fee. Alternatively, if there is no anticipated future need for the collected blood, or if it does not meet standards needed for future treatment, it will be used in NIH-approved research studies. Participants and their family doctor or the baby s pediatrician will be contacted twice a year for information about changes in the baby s health. Participants may also be asked permission to perform new tests developed by researchers. ...
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.
Nitric oxide is important in regulating blood vessel dilation, and consequently, blood flow. This gas is continuously produced by cells that line the blood vessels. It is also transported from the lungs by hemoglobin in red blood cells. This study will examine how this gas regulates blood vessels and blood flow in people with sickle cell anemia. It will also look at a possible benefit of using certain genetic information to compare the white blood cells of people with sickle cell anemia to those without the disease. Patients with sickle cell anemia and healthy normal volunteers 18 to 65 years of age may be eligible for this study. Candidates will be screened with a medical history, cardiovascular physical examination, electrocardiogram and routine blood tests. Participation of volunteers without sickle cell anemia will be limited to a single blood draw for genetic study. Sickle cell disease patients will undergo the following procedures: Patients will lie in a reclining chair during the study. After administration of a local anesthetic, small tubes will be inserted through a needle into the artery and vein of the patient's forearm. These are used to measure blood pressure and draw blood samples during the study. Forearm blood flow will be measured using pressure cuffs placed on the wrist and upper arm, and a strain gauge (a rubber band device) placed around the forearm. When the cuffs are inflated, blood flows into the arm, stretching the strain gauge, and the flow measurement is recorded. A small lamp will be positioned over the hand. Light reflected back from the hand provides information about nitric oxide and hemoglobin in the blood of the skin. A squeezing device called a dynamometer will be used to measure handgrip strength. Baseline blood flow, nitric oxide, hemoglobin, and handgrip will be measured after an infusion of glucose (sugar) and water. These measurements will be repeated at various times before, during and after administration of small doses of the following drugs: - Sodium nitroprusside - causes blood vessels to dilate and increases blood flow to the heart - Acetylcholine - causes blood vessels to dilate and slows heart rate - LNMMA - decreases blood flow by blocking the production of nitric oxide There will be a 20- to 30-minute rest period between injections of the different drugs. When the above tests are completed, the patient will breathe a mixture of room air and nitric oxide for 1 hour through a facemask placed over the face, after which forearm blood flow and light reflected from the hand will be measured. Then the patient will do the handgrip exercise for 5 minutes, after which blood flow and hand lamp measurements will be taken. After a 20-minute rest period (with continued breathing of room air/nitric oxide), L-NMMA will be infused again. The handgrip exercise, blood flow and hand lamp measurements will be repeated. The face mask will then be removed, and the tubes will be removed 20 minutes later. Blood samples will be collected at various times during the 5- to 6-hour study through the tubes in the arm. Some of the blood will be used to look at genes that make proteins involved in cell-to-cell communication, inflammation, and in making red and white blood cells stick to the lining of blood vessels.
The purpose of this study is to determine if hydroxyurea therapy is effective in the prevention of chronic end organ damage in pediatric patients with sickle cell anemia.
To determine how long blood transfusions are needed for primary stroke prevention. Also, to determine the duration of risk associated with abnormal transcranial Doppler ultrasound (TCD) and to determine the specificity of the stroke risk model developed in STOP 1 in patients with abnormal TCD measurements.
OBJECTIVES: I. Phase II trial to determine surgical morbidity of decompression coring, including any adverse events in the perioperative period and the rate of secondary medical or surgical interventions. II. Collect preliminary data to determine if decompression coring results in a substantial improvement in pain and mobility compared to conservative therapy in patients with avascular necrosis of the hip related to sickle cell disease.
OBJECTIVES: I. Determine the efficacy of bone marrow transplantation using matched related donors in patients with nonmalignant hematologic disorders. II. Determine the quality of life, absence of adverse effects (e.g., graft versus host disease and B cell lymphoproliferative disease), and completeness of recovery of their underlying condition in these patients with this treatment regimen.
Sickle cell anemia is a genetic disorder that results from a single nucleotide substitution in codon 6 of the beta-globin gene which, in the homozygous state, produces an abnormal hemoglobin that is prone to polymer formation when deoxygenated. The polymerized hemoglobin leads to impaired deformability and sickling of red blood cells which subsequently lodge in end-arterioles producing the classic and most prominent feature of the disorder, repeated vasoocclusive crises. Despite knowledge of the precise genetic defect for decades, only recently has there been therapeutic impact based upon this knowledge when a clear benefit from treatment with hydroxyurea, a cell cycle-specific agent administered to induce production of fetal hemoglobin (HbF) by stimulating gamma-globin synthesis, was reported in patients with sickle cell disease (SCD). The reduction in the frequency and severity of vasoocclusive crises seen has been attributed to the increase in HbF levels in responsive patients. While the majority of patients demonstrate a rise in HbF, not all such patients benefit from treatment. Given these results, alternative agents that also stimulate the production of HbF warrant investigation in the treatment of SCD. Recombinant-methionyl human stem cell factor (SCF) is a hematopoietic growth factor with activity on immature hematopoietic progenitor cells. SCF stimulates the production of HbF in vitro and in vivo, and this effect is attainable without the myelosuppression associated with hydroxyurea. In this phase I/II trial, we will administer SCF in a dose escalating fashion to patients with sickling disorders. Parameters to be measured are HbF levels, F cell levels, peripheral blood CD34 levels, frequency, duration, and severity of vasoocclusive crises, and toxicity.