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A 24-year-old African American male with sickle cell disease has been followed by a hematologist since infancy. Two years ago, he was started on hydroxyurea for frequent pain crises but has not achieved good control. The addition of a Gardos channel blocking agent is being considered. What is the mechanism of action of this class of medications?
Prevents RBC dehydration by inhibiting K+ efflux
Increases production of hemoglobin F
Prevents dehydration of RBCs by inhibiting Ca2+ efflux
Encourages alkalinization of the blood by facilitating H+/K+ antiporter activity
Increases water diffusion by increasing activity of aquaporin-1 receptors
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A 5-year-old African American boy presents with extreme abdominal pain. He has a history of several such episodes, as well as acute episodes of extreme bone pain. He has previously presented with the findings illustrated in Figure A. A peripheral blood smear is obtained, and is shown in Figure B. What is the most likely mechanism responsible for this patient's disorder?
Tri-nucleotide repeat amplification
Mutation in the gene coding for hemoglobin-alpha
Point mutation at the 6th position of the ß-hemoglobin chain
Increased levels of hemoglobin-F
Reduced levels of folic acid
A 4-year-old African American boy presents with extreme abdominal pain. He has had similar episodes in the past. A peripheral smear is obtained, and shows the findings illustrated in Figure A. Which of the following is a mechanism which can precipitate this condition?
Elevated cellular pH
Elevated arterial oxygen concentration
Elevated hemoglobin F levels
Travel from high to low elevation geographical area
Patients with the diagnosis of sickle cell anemia make a specific type of hemoglobin known as HgbS. This mutation results in the sickling of their red blood cells when exposed to inciting factors such as hypoxic conditions. Patients are often treated with hydroxyurea, which has which of the following direct effects on their hemoglobin physiology?
Increases oxygen carrying capacity of hemoglobin
Decreases oxygen carrying capacity of hemoglobin
Increases levels of fetal hemoglobin (HgbF)
Decreases levels of HgbS
Decreases levels of fetal hemoglobin (HgbF)
A 17-year-old African-American male presents to his family physician after noticing red-tinged urine the week before, when he was suffering from a cold. The patient states that he had experienced that before. His father is with him and says that this happens to him on occasion as well. What is the most likely diagnosis for this patient?
Acute interstitial nephritis
Sickle cell trait
A 7-year-old girl with a history of painful crises and impaired growth presents for evaluation of sickle cell disease. You perform hemoglobin gel electrophoresis, and diagnose her with homozygous sickle cell disease. Which of the gel electrophoresis lanes in Figure A is hers (Lanes 1 and 5 contain the reference marker samples including Hemoglobin variants A, F, S, C)?
An 8-year-old boy complains of extremity pain and difficulty "catching his breath" while running on the playground. His mother also reports that he complains of intermittent abdominal pain. Physical examination reveals splenomegaly. The patient's blood smear is shown in Figure A. What is the most likely mutation present?
Glutamic acid to valine
Glutamine to valine