Which of the following molecular actions most likely mediated the therapeutic effect of amphotericin B in the patient's disease?

Correct Answer: B

Rationale: The correct answer is B: Pore formation in fungal cell membrane. Amphotericin B is a polyene antifungal medication that works by binding to ergosterol in the fungal cell membrane, leading to the formation of pores. This disrupts membrane integrity, causing leakage of intracellular components and ultimately cell death. This mechanism of action is specific to fungal cells, as mammalian cells contain cholesterol instead of ergosterol. Choice A is incorrect because amphotericin B does not activate fungal cytochrome P-450 enzymes; instead, it disrupts the fungal cell membrane. Choice C is incorrect because amphotericin B does not inhibit fungal cytochrome P-450 enzymes. Choice D is incorrect because amphotericin B does not inhibit fungal mitosis; its primary mechanism of action is through membrane disruption.

Correct Answer: B

Rationale: The correct answer is B: Albuterol. Albuterol is a bronchodilator that works by relaxing bronchial muscles, making it easier to breathe. It is commonly prescribed for the treatment of asthma to provide quick relief of symptoms. Prednisone (A) is a corticosteroid used for long-term control of asthma but does not directly relax bronchial muscles. Ipratropium (C) is an anticholinergic medication that helps open the airways but does not primarily target bronchial muscle relaxation. Methotrexate (D) is an immunosuppressant used for conditions like rheumatoid arthritis, not for asthma treatment.

Correct Answer: B

Rationale: The correct answer is B: Activating peroxisome proliferator-activated receptor alpha (PPAR-alpha). Fenofibrate is a fibrate medication that works by activating PPAR-alpha receptors. PPAR-alpha activation leads to increased expression of genes involved in lipid metabolism, resulting in decreased triglyceride levels and increased HDL cholesterol levels. This mechanism of action is specific to fenofibrate and other fibrates. Now, let's analyze why the other choices are incorrect: A: Inhibiting HMG-CoA reductase in the liver - This is the mechanism of action of statins, not fibrates like fenofibrate. C: Blocking calcium channels in the blood vessels - This is unrelated to the mechanism of action of fenofibrate and is more commonly associated with calcium channel blockers used in hypertension management. D: Increasing the absorption of cholesterol in the intestines - This is the mechanism of action of bile acid sequestrants, not fibrates like fenofibrate

Correct Answer: B

Rationale: The correct answer is B: Improving insulin sensitivity in peripheral tissues. Metformin works by decreasing insulin resistance in peripheral tissues, making them more responsive to insulin. This helps to lower blood glucose levels by improving glucose uptake and utilization. Choice A is incorrect because metformin does not directly increase insulin secretion from the pancreas. Choice C is incorrect as metformin does not inhibit glucose absorption in the intestines. Choice D is incorrect as metformin primarily reduces blood glucose levels by improving insulin sensitivity rather than increasing renal glucose excretion.

Correct Answer: A

Rationale: The correct answer is A: Hair loss. Chemotherapy drugs target fast-growing cells, including hair follicles, leading to hair loss. This is a well-known side effect of chemotherapy. Increased appetite (B) is not a common side effect; in fact, many patients experience loss of appetite. Dehydration (C) can occur due to other reasons like nausea and vomiting, not directly from chemotherapy. Drowsiness (D) is more associated with certain medications or the cancer itself, not a direct side effect of chemotherapy.