High-density lipoprotein (HDL) is:

Correct Answer: A

Rationale: The correct answer is A. HDL is a lipoprotein associated with a decreased risk of atherosclerosis and coronary artery disease due to its small amounts of cholesterol and triglycerides. It is also known as alpha-lipoprotein. Choice B is incorrect as it describes LDL, not HDL. Choice C is incorrect because high amounts of cholesterol are associated with LDL, not HDL. Choice D is incorrect as it describes chylomicrons, not HDL.

Correct Answer: D

Rationale: The correct answer is D, as hypocalcemia in adults can result from various causes. Hypoparathyroidism leads to decreased parathyroid hormone and calcium levels. Vitamin D deficiency impairs calcium absorption. Renal failure and malabsorption can disrupt calcium balance. Therefore, all options A, B, and C contribute to hypocalcemia in adults. Other choices are incorrect because they do not comprehensively cover the major causes of hypocalcemia in adults.

Correct Answer: A

Rationale: The correct answer is A: Osmotic diuretics. Osmotic diuretics are the least potent diuretics as they work by creating an osmotic force that prevents water reabsorption in the nephron, leading to increased urine output. Loop diuretics (B) are more potent as they act on the ascending loop of Henle. Thiazide diuretics (C) are also more potent as they act on the distal convoluted tubule. Potassium-sparing diuretics (D) are relatively less potent than loop and thiazide diuretics but are still more potent than osmotic diuretics.

Correct Answer: B

Rationale: The correct answer is B: Pancytopenia. Chloramphenicol is known to cause bone marrow suppression, leading to a decrease in red blood cells, white blood cells, and platelets. This results in pancytopenia, which can manifest as anemia, increased risk of infections, and easy bruising or bleeding. Nephrotoxicity (A), hepatotoxicity (C), and ototoxicity (D) are not common side effects of chloramphenicol. Pancytopenia is a well-documented adverse effect of this antibiotic due to its impact on bone marrow function.

Correct Answer: B

Rationale: The correct answer is B: Headache, dizziness, insomnia. Fluoroquinolones are known to cause central nervous system side effects such as headache, dizziness, and insomnia. These unwanted effects are commonly reported with the use of fluoroquinolones. Hallucinations (choice A) are not typically associated with fluoroquinolones. Hypertension (choice C) is not a common side effect of fluoroquinolones. Immunetoxicity (choice D) is a general term and not a specific unwanted effect of fluoroquinolones. Therefore, choice B is the correct answer due to the known side effects of fluoroquinolones on the central nervous system.