2 Clinical Trials for Various Conditions
This study will collect blood samples for use in laboratory studies of malaria. The World Health Organization reports that 40 percent of the world's population is at risk for malaria, mostly in the poorest countries. It is a serious disease caused by parasites. Each year, 300-500 million infections lead to more than a million deaths. However, there are traits in red blood cells (erythrocyte) that protect people against malaria. In this study, polymorphism refers to the various kinds of red blood cell traits. The sickle cell trait is an example of one that seems to offer a natural survival advantage in children where malaria is common. Researchers at the Laboratory of Malaria and Vector Research are investigating ways in which the blood cell traits can offer such protection, and new knowledge gained can bring about medical advances. Of particular importance is studying how the malaria organism, Plasmodium, survives inside different red blood cells. A steady, consistent, and reliable supply of fresh whole blood is necessary for testing. Patients 18 to 65, weighing more than 110 lbs. and who do not have anemia or known HIV, Hepatitis C, or Hepatitis B may be eligible for this study. Patients will undergo a medical history and general assessment including vital signs of temperature, heart rate, and blood pressure. Blood will be collected from a vein in the arm, or rarely a vein in the hand. A complete blood count, or CBC, will be done to ensure that blood levels are sufficient and that blood donation is safe for a patient to do. Patients need to have enough hemoglobin, the part of red blood cells that transports oxygen throughout the body. The blood will also be tested to confirm the type of red blood cell traits of patients. About 1 to 8 tablespoons may be collected, but most blood samples will be small, that is, 1 to 4 teaspoons. After the patients' first visit, sessions will take 5-20 minutes. Blood collection will total no more than 2 cups from a donor during any 6-week period. Although the frequency of blood donations is not known at this time, it is unlikely that a patient will be asked to donate blood more than four times a year. It may be important for patients to undergo a repeat CBC or tests for blood chemistry if results are needed for research. Risks associated with blood collection are considered minimal. They include discomfort, occasional bruising or bleeding at the puncture site, and faintness. In this study, it is possible that a small amount of blood may be stored for future research, to help the researchers to learn more about malaria. There are no plans for the results from the various research laboratory tests to be made available to patients or to their private doctors. However, patients in this study may discuss the results of routine medical tests with the study investigators. Some of the blood collected will be tested for genetic conditions. Through genetic testing, researchers can learn more about how health or illness may be passed on to people by their parents, or from people to their children. All results of tests will remain confidential. Blood samples will be labeled by code, and reference to patients' identities will be protected. Participants will receive $50 for each blood donation. This study will not have a direct benefit for participants. Future research that uses their blood samples will help researchers to learn about malaria as well as how to prevent or treat the disease.
Background: Some people with the same disorder on a genetic level have more complications than others. Researchers want to look for a link between the PKLR gene and sickle cell disease (SCD) symptoms. The PKLR gene helps create a protein, called pyruvate kinase that is essential in normal functioning of the red blood cell. Differences in the PKLR gene, called genetic variants, may cause some changes in the pyruvate kinase protein and other proteins, that can affect functioning of the red blood cell adding to the effect of SCD. Researchers can study these differences by looking at DNA (the material that determines inherited characteristics). Objective: To study how the PKLR gene affects sickle cell disease. Eligibility: Adults ages 18-80 of African descent. They may have sickle cell disease or not. They must not have had a transfusion recently or have a known deficiency of pyruvate kinase. They cannot be pregnant. Design: Participants will be screened with questions. Participants will have blood drawn by needle in an arm vein. The blood will be genetically tested. Not much is known about how genes affect SCD, so the test results will not be shared with participants or their doctors. ...