Which of the following statements concerning nitrate mechanism of action is True?

Correct Answer: D

Rationale: The correct answer is D: All of the above. Rationale: A: Therapeutically active nitrates release NO, which activates guanylyl cyclase in vascular smooth muscle, leading to vasodilation. B: Nitric oxide activates soluble guanylyl cyclase, promoting cGMP production, causing vasodilation and reducing blood pressure. C: Nitrates decrease myocardial oxygen demand by reducing preload and afterload, while also increasing oxygen delivery by dilating coronary arteries. Summary: Option A highlights the release of NO, contributing to vasodilation. Option B explains NO's role in activating guanylyl cyclase. Option C describes the dual mechanism of nitrates in decreasing oxygen demand and increasing oxygen delivery. Therefore, the correct answer includes all valid statements regarding nitrate mechanism of action.

Correct Answer: A

Rationale: The correct answer is A because hypothyroidism is indeed a syndrome caused by a deficiency of thyroid hormones, leading to a slowdown of body functions. This is supported by clinical manifestations such as fatigue, weight gain, and cold intolerance. Choice B is incorrect as it describes hyperthyroidism, not hypothyroidism. Choice C refers to severe hypothyroidism in adults and is not a statement. Choice D is a form of severe congenital hypothyroidism, not a statement about hypothyroidism in general. Therefore, choice A is the only accurate statement among the options.

Correct Answer: C

Rationale: Sure. Tamoxifen is classified as an antiestrogen because it competitively binds to estrogen receptors, blocking the effects of estrogen. It is commonly used in breast cancer treatment to inhibit estrogen-stimulated tumor growth. Antiprogestins (choice A) block progesterone effects, not estrogen. Antiandrogens (choice B) block androgen effects, not estrogen. Androgens (choice D) are male sex hormones, unrelated to tamoxifen's mechanism of action.

Correct Answer: C

Rationale: The correct answer is C: Zafirlukast (Accolate). Zafirlukast is a leukotriene receptor antagonist that specifically blocks the action of leukotriene D4 (LTD4) at its receptor. This drug helps in reducing inflammation in conditions like asthma by blocking the effects of LTD4. Ibuprofen (A) and Diclofenac (D) are nonsteroidal anti-inflammatory drugs (NSAIDs) that work by inhibiting cyclooxygenase enzymes. Zileuton (B) is a 5-lipoxygenase inhibitor that blocks the formation of leukotrienes but does not specifically target the LTD4 receptor. Therefore, the correct choice is C as it directly blocks the LTD4 receptor, unlike the other options.

Correct Answer: D

Rationale: Rationale: Interferon alpha is indicated for treating viral infections and certain cancers, making it suitable for Hepatitis C, Kaposi's sarcoma, and Condyloma acuminatum. Therefore, the correct answer is D. Choice A is correct as interferon alpha is used in Hepatitis C treatment. Choice B is also correct as it is used in treating Kaposi's sarcoma. Choice C is correct as it is used in treating Condyloma acuminatum. Therefore, choosing all of the above (D) is the correct answer as interferon alpha is indicated for all these conditions.