Which of the following statements about calcitonin is true:

Correct Answer: D

Rationale: Rationale: A: True. Calcitonin is indeed secreted by parafollicular cells of the thyroid and consists of 32 amino acids. B: True. Calcitonin lowers serum calcium and phosphate levels by acting on bones and kidneys. C: True. Calcitonin inhibits osteoclastic bone resorption, thereby protecting bone density. Therefore, the correct answer is D, as all statements are accurate and collectively describe the functions and characteristics of calcitonin.

Correct Answer: A

Rationale: The correct answer is A: Furosemide (Lasix). Furosemide is a loop diuretic that competitively blocks chloride channels in the ascending loop of Henle, preventing the reabsorption of sodium, potassium, and chloride in the renal tubules. This mechanism leads to increased excretion of these ions and water, resulting in diuresis. Acetazolamide (B) inhibits carbonic anhydrase, Triamterene (C) blocks sodium channels, and Mannitol (D) is an osmotic diuretic. Therefore, these choices do not competitively block chloride channels like Furosemide does in the renal tubular cells.

Correct Answer: C

Rationale: The correct answer is C: Myconazol. Myconazol is not an antibiotic; it is an antifungal drug that belongs to the class of azole antifungals. Antibiotics target bacteria, while antifungal drugs target fungi. Amphotericin B, Nystatin, and Griseofulvin are antifungal drugs that are also considered antibiotics because they inhibit the growth of fungi by various mechanisms. Amphotericin B disrupts fungal cell membrane function, Nystatin binds to ergosterol in fungal cell membranes, and Griseofulvin interferes with fungal cell division. Therefore, Myconazol is the correct answer as it does not belong to the antibiotic class.

Correct Answer: C

Rationale: Step-by-step rationale for choice C: 1. Sodium stibogluconate is a first-line treatment for leishmaniasis. 2. It is an antimonial compound effective against Leishmania parasites. 3. It is administered intravenously for visceral leishmaniasis. 4. Has been used for decades with proven efficacy. Summary of other choices: A: Pyrimethamine - used for malaria, not leishmaniasis. B: Albendazole - used for helminthic infections, not leishmaniasis. D: Tinidazole - used for protozoal infections like Giardiasis, not leishmaniasis.

Correct Answer: A

Rationale: The correct answer is A: Provide synergism resulting from the use of anticancer drugs with different mechanisms combination. Rational combination of anticancer drugs with different mechanisms can target multiple pathways in cancer cells, leading to enhanced efficacy and reduced chances of drug resistance. This synergy can result in improved treatment outcomes. Choices B, C, and D are incorrect: B: Providing synergism from using anticancer drugs with the same mechanisms combination would not enhance the effectiveness of treatment. C: Stimulating the immune system is a different approach to cancer treatment and is not related to rational drug combinations. D: Stimulation of cell proliferation would be counterproductive in cancer treatment as the goal is to inhibit cancer cell growth, not promote it.