A 65-year-old man comes to the physician because of a 1-month history of progressive back pain. He has also had a 5-kg (11-lb) weight loss over the past 3 months. His only medications are a daily multivitamin and ibuprofen, which he takes daily for the back pain. Physical examination shows tenderness to palpation over the lower spine and the left iliac crest. His hemoglobin concentration is 9.3 g/dL, his serum calcium concentration is 12 mg/dL, and his serum creatinine concentration is 2.1 mg/dL. A bone marrow biopsy shows 21% plasma cells. A diagnosis of multiple myeloma is established. In preparation for an autologous hematopoietic stem cell transplantation, the patient receives a myeloablative treatment regimen that includes busulfan. Which of the following drugs acts via a similar mechanism of action to busulfan?
AEtoposide
BVemurafenib
CVincristine
DCytarabine
ELomustine
An investigator studying epigenetic mechanisms isolates histone proteins, the structural motifs involved in DNA binding and regulation of transcription. The peptide bonds of histone proteins are hydrolyzed and one type of amino acid is isolated. At normal body pH, this amino acid has a net charge of +1 . The investigator performs titration of this amino acid and obtains the graph shown. The isolated amino acid is most likely which of the following?
AProline
BLysine
CAspartate
DSerine
EHistidine
A 5-year-old African-American boy is brought to the physician because of fatigue and night sweats for the past month. During this time, he has also lost 3 kg (6.6 lbs). Before the onset of symptoms, he had been healthy except for a febrile seizure as an infant. His brother had chickenpox 2 months ago. He is at the 75th percentile for height and 50th percentile for weight. He appears markedly fatigued. His temperature is 38°C (100.4°F), pulse is 95/min, respirations are 19/min, and blood pressure is 100/60 mm Hg. Lung and cardiac examination is normal. There are enlarged, nontender lymph nodes bilaterally in the neck. The abdomen is soft and nontender. A complete blood count shows: Leukocyte count 8,000/mm³ Hemoglobin 9.1 g/dL Hematocrit 26.9% Platelet count 34,000/mm³ Serum Na+ 135 mEq/L K+ 4.5 mEq/L Cl- 101 mEq/L HCO3- 27 mEq/L Urea nitrogen 9 mg/dL Creatinine 0.7 mg/dL Ca2+ 8.8 mg/dL PCR testing demonstrates a 9:22 chromosomal translocation. The patient is diagnosed with Philadelphia chromosome-positive acute lymphoblastic leukemia. Which of the following is the most appropriate targeted therapy component?
ACladribine
BImatinib
CHydroxyurea
DAll-trans retinoic acid
ETransfuse platelets
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