The action of insulin is potentiated by:

Correct Answer: C

Rationale: The correct answer is C: Biguanides. Biguanides, such as metformin, potentiate the action of insulin by improving insulin sensitivity in tissues, reducing hepatic glucose production, and enhancing peripheral glucose uptake. Sulphonylureas (A) stimulate insulin secretion, glucagon (B) increases blood glucose levels, and D is incorrect as biguanides do potentiate insulin action.

Correct Answer: D

Rationale: The correct answer is D: Idiopathic nephrotic syndrome. Cyclosporine A is indicated for the treatment of idiopathic nephrotic syndrome due to its immunosuppressive properties that help reduce proteinuria and preserve renal function. In contrast, choices A, B, and C are incorrect because cyclosporine A is not typically used for secondary immunodeficiency, hairy cell leukemia, or primary immunodeficiency. These conditions require different treatment approaches not involving cyclosporine A.

Correct Answer: A

Rationale: The correct answer is A. Pellagra is caused by a deficiency of niacin, leading to symptoms like skin eruptions, digestive and nervous system disturbances, and mental deterioration. Choice B refers to beriberi, caused by thiamin deficiency. Option C describes pernicious anemia, caused by a lack of vitamin B12. Option D is incorrect as it includes all the above conditions, which is not the case. Overall, the key points to remember are the specific symptoms of pellagra and the deficiency of niacin as the cause.

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: Osteomalacia. Vitamin D3 is indicated for the treatment of osteomalacia, a condition characterized by softening of the bones due to a deficiency of vitamin D. It helps in the absorption of calcium and phosphorus, leading to proper bone mineralization. A: Hypercalcemia is not an indication for vitamin D3 as it can worsen the condition by increasing calcium levels further. B: Paget's disease is not a primary indication for vitamin D3 therapy. Treatment usually involves bisphosphonates. C: Hypophosphatemia is a condition where there is low phosphate levels, and treatment involves phosphate supplementation, not just vitamin D3.