All of the following statements concerning the bile acid-binding resins are true, EXCEPT:

Correct Answer: C

Rationale: The correct answer is C because bile acid-binding resins, such as cholestyramine, can actually slow the progression of atherosclerotic lesions when used alone. These resins work by binding bile acids in the intestine, leading to increased bile acid excretion, which in turn results in increased LDL receptor expression on hepatocytes. This promotes the clearance of LDL from the bloodstream, thus reducing total cholesterol and LDL levels (Choice A). Bile acid-binding resins are not contraindicated in hypertriglyceridemia; in fact, they can be beneficial in reducing triglyceride levels. Lastly, while they are effective in type II hyperlipidemia, they are not always the first-line agents of choice and are often used in combination with other lipid-lowering drugs (Choice D).

Correct Answer: D

Rationale: The correct answer is D because plicamycin is indicated for testicular cancers refractory to standard treatment, Paget’s disease, and hypercalcemia of malignancy. Plicamycin inhibits bone resorption and reduces serum calcium levels in patients with hypercalcemia of malignancy. It also has cytotoxic effects on certain types of cancer cells, including testicular cancers. Therefore, it is used for all of the mentioned conditions. Choices A, B, and C are incorrect because plicamycin is not limited to only one specific condition, but rather can be used for multiple indications.

Correct Answer: A

Rationale: The correct answer is A: TRUE. Some microorganisms can indeed develop alternative metabolic pathways to bypass the inhibition caused by a drug. This is a common phenomenon known as drug resistance in microbial populations. Other choices are incorrect: B is false because drug resistance through alternative pathways is a known fact; C (All) is incorrect as not all microorganisms exhibit this behavior; and D (None) is incorrect as some microorganisms do develop alternative pathways to counter drug inhibition.

Correct Answer: B

Rationale: The correct answer is B: Inhibition of dihydropteroate synthase. Sulfonamides work by inhibiting dihydropteroate synthase, an enzyme involved in the folate synthesis pathway in bacteria. This disruption leads to a decrease in production of essential nucleotides, ultimately inhibiting bacterial growth. A: Inhibition of dihydropteroate reductase is incorrect as sulfonamides target dihydropteroate synthase, not reductase. C: Inhibition of cyclooxygenase is incorrect as this mechanism is related to NSAIDs, not sulfonamides. D: Activation of DNA gyrase is incorrect as this mechanism is associated with antibiotics like fluoroquinolones, not sulfonamides.

Correct Answer: A

Rationale: The correct answer is A: Metronidazole and diloxanide. Metronidazole is effective against the invasive form of Entamoeba histolytica, the parasite causing amebiasis. Diloxanide is used to eliminate the non-invasive cyst form of the parasite in the intestine. Streptomycin (choice B) is not effective against amebiasis. Iodoquinol (choice C) is used for non-invasive amebiasis but not the intestinal form. Emetine (choice D) is reserved for extraintestinal disease and is not commonly used due to its toxicity.