This drug is used in treating supraventricular tachycardias:

Correct Answer: A

Rationale: Step-by-step rationale for why A (Digoxin) is the correct answer: 1. Digoxin is a cardiac glycoside that slows conduction through the AV node, making it effective in controlling supraventricular tachycardias. 2. It increases the refractory period of the AV node, reducing the heart rate. 3. Digoxin is not a vasopressor like Dobutamine or Dopamine, which are used for different indications. 4. Amrinone is a phosphodiesterase inhibitor, primarily used in heart failure, not specifically for supraventricular tachycardias.

Correct Answer: A

Rationale: The correct answer is A because hormones are indeed products of endocrine gland secretion. Endocrine glands release hormones directly into the bloodstream to regulate various physiological processes. Choice B is incorrect as hormones are not mediators of the inflammatory process. Choice C is wrong because hormones are not by-products of tissue metabolism but rather specific signaling molecules. Choice D is incorrect as hormones are not products of exocrine gland secretion but rather endocrine glands.

Correct Answer: A

Rationale: The correct answer is A because thiazolidinediones work by activating peroxisome proliferator-activated receptor gamma (PPAR-γ), which leads to increased glucose uptake and metabolism in muscle and adipose tissues, thereby reducing insulin resistance. It does not reduce carbohydrate absorption from the gut (choice B) or stimulate beta islet cells to produce insulin (choice C). Therefore, the correct answer is A as it directly addresses the mechanism of action of thiazolidinediones.

Correct Answer: D

Rationale: Rationale: Glucocorticoids are indicated for a wide range of conditions due to their anti-inflammatory and immunosuppressive effects. A: Glucocorticoids are used in both chronic (Addison's disease) and acute adrenocortical insufficiency to replace deficient cortisol levels. B: Glucocorticoids are essential for preventing rejection in organ transplant recipients by suppressing the immune response. C: Glucocorticoids are effective in managing inflammatory conditions of bones and joints by reducing inflammation and pain. Therefore, the correct answer is D because glucocorticoids are indicated for all the mentioned conditions due to their diverse mechanisms of action.

Correct Answer: D

Rationale: The correct answer is D. Glucocorticoids exert their immunosuppressive effect through multiple mechanisms. A: Glucocorticoids reduce lymphocyte (T and B cells) concentration and inhibit the function of tissue macrophages and other antigen-presenting cells, leading to decreased immune response. B: Glucocorticoids suppress cyclooxygenase II expression, reducing prostaglandin synthesis, which is involved in inflammation. C: Glucocorticoids activate phospholipase A2, reducing prostaglandin and leukotriene synthesis, further dampening the immune response. Therefore, all of the choices (A, B, and C) contribute to the immunosuppressive effect of glucocorticoids.