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|Effects of Miconazole on Blood Flow
|National Heart, Lung, and Blood Institute (NHLBI)
|This study will investigate the effect of the drug miconazole on blood vessel dilation. Miconazole stops production of EDHF, a substance that causes arteries to dilate. EDHF is produced by the cells that line blood vessels. Normal volunteers between the ages of 21 to 60 may participate in this study. Candidates will be screened for eligibility with a medical history, physical examination, electrocardiogram and routine laboratory tests. Those enrolled will be injected with miconazole to study its effects on blood vessels. Study participants will take three aspirin tablets. After administration of a local anesthetic, small tubes will be inserted through a needle into the artery and vein of the forearm. These will be used to measure blood pressure and to 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 will flow into the arm, stretching the strain gauge, and the flow measurement will be recorded. Small doses of four drugs-bradykinin, sodium nitroprusside, miconazole, and LNMMA-will be given through the arterial catheter. Bradykinin stimulates the release of EDHF and can lower blood pressure. Sodium nitroprusside causes blood vessels to dilate and is used to treat high blood pressure and heart failure. Miconazole is commonly prescribed to treat various infections, including vaginal yeast infections, jock itch and athlete's foot. In much higher doses, it is used to treat fungal infections that have spread to the lungs, brain, kidneys, or bladder. LNMMA inhibits production of nitric oxide, another substance produced by the lining cells of blood vessels. Blood flow will be measured throughout the study, which will last approximately 3 hours.
|Nitric Oxide to Improve Blood Flow in Sickle Cell Disease
|National Institutes of Health Clinical Center (CC)
|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.
|Atorvastatin Therapy to Improve Endothelial Function in Sickle Cell Disease
|National Institutes of Health Clinical Center (CC)
|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 Effect of Lopinavir/Ritonavir on Endothelial Function
|National Institutes of Health Clinical Center (CC)
|This study will examine how the anti-HIV protease inhibitor lopinavir/ritonavir (Kaletra® (Registered Trademark)) affects the function of the endothelium (lining of the arteries). Medications such as protease inhibitors can dramatically change the course of HIV infection in many patients; however, among their side effects is development of abnormal lipid levels resulting in high cholesterol and insulin resistance. These side effects may damage the lining of the arteries that supply blood to the heart, leading to premature coronary artery disease. The study will determine whether lopinavir/ritonavir directly affects endothelial function and whether it alters cholesterol levels, glucose tolerance, and markers of inflammation in people who take the drug for 4 weeks. Healthy normal volunteers between 18 and 40 years of age may be eligible for this study. Candidates must be HIV-negative and have no history of heart disease, hypertension, or diabetes mellitus. They must not have smoked for at least 6 weeks before entering the study. Volunteers will be screened with a medical history, physical examination, blood tests (including a pregnancy test for women of childbearing potential), and electrocardiogram. In addition, candidates will have an oral glucose tolerance test (see description below). Participants will undergo the following procedures: - Lopinavir/ritonavir: 4 weeks (3 capsules twice a day) beginning study day 1 - Flow-mediated vasodilatation test (study days 0 and 29) - An ultrasound device for measuring the size of the brachial artery (artery in the upper arm) is placed just above the elbow. The size of the artery is measured before and 5 minutes after blood flow to the arm is stopped for 5 minutes, using a blood pressure cuff. The artery is also measured before and after taking nitroglycerin, a medicine that dilates blood vessels. These measurements tell how well the drug treatment works on the cells lining the brachial artery, which is an indicator of coronary artery function. This test takes about 1.5 hours. - Forearm blood-flow test (study days 1 and 30): Small tubes are inserted into an artery and vein in the forearm at the inside of the elbow. Blood pressure cuffs are placed around the upper arm and wrist, and a strain gauge (a rubber band-like device) is placed around the forearm. When the blood pressure cuffs are inflated, blood flows into the forearm, stretching the strain gauge at a rate proportional to the blood flow. When the devices are in place, a salt water solution is injected in the small tube in the artery. After 20 minutes, small doses of the following drugs are given through the catheter at various intervals: 1) L-NMMA (blocks production of nitric oxide, a substance produced by the blood vessels that causes them to dilate); 2) sodium nitroprusside (dilates blood vessels, increasing blood flow); 3) acetylcholine (lowers blood pressure); and 4) acetylcholine plus L-NMMA. The effect of the different drugs on blood flow in the forearm is measured. The study takes about 2 hours to complete. - Blood tests (screening and study days 1,15, 30, and 44) - Electrocardiogram (at screening and on study day 30) - Oral glucose tolerance test (at screening and on study day 30) - A blood sample is collected. Then, the subject drinks 300 milliliters of a glucose solution (a liquid that contains sugar dissolved in water). Two hours after drinking the solution, blood is drawn again to examine how the body responds to the increase blood sugar levels.
|Clevidipine in the Perioperative Treatment of Hypertension (ECLISPE-SNP)
|The Medicines Company
|The purpose of this study is to establish the safety of clevidipine in the treatment of perioperative hypertension. Approximately 250-500 patients with perioperative hypertension undergoing coronary artery bypass grafting (CABG), off-pump coronary artery bypass (OPCAB) or minimally invasive direct coronary artery bypass (MIDCAB) surgery and/or valve replacement/repair procedures were anticipated to be randomly assigned to one of two treatment groups: clevidipine or sodium nitroprusside.
|Therapeutic Application of Intravascular Nitrite for Sickle Cell Disease
|National Heart, Lung, and Blood Institute (NHLBI)
|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.
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