Sulphonylureas act by:

Correct Answer: D

Rationale: Step 1: Sulphonylureas are a class of drugs that stimulate insulin release. Step 2: They act by binding to the sulphonylurea receptor on beta islet cells of the pancreas. Step 3: This binding triggers a cascade of events leading to insulin release. Step 4: Insulin then helps lower blood glucose levels. Conclusion: Choice D is correct as it accurately describes the mechanism of action of sulphonylureas. Choices A, B, and C are incorrect as they do not reflect the primary mode of action of sulphonylureas.

Correct Answer: B

Rationale: Step 1: Histamine H1 antagonists are commonly used to treat allergic reactions by blocking histamine release. Step 2: Nausea and vomiting in pregnancy can be treated with H1 antagonists like doxylamine. Step 3: Sleep disorders are not typically treated with H1 antagonists, but rather with medications targeting other pathways. Step 4: Seizure states are not a common indication for H1 antagonists and have no direct relation to histamine pathways. Step 5: Therefore, choice B is the correct answer as it does not align with the typical indications for histamine H1 antagonists.

Correct Answer: B

Rationale: The correct answer is B because vitamin B1, also known as thiamine, is indeed an essential coenzyme for the oxidative decarboxylation of alpha-keto acids, including the conversion of pyruvate to acetyl coenzyme A in the citric acid cycle. This process is crucial for energy production in the form of ATP. Choice A is incorrect because vitamin B1 is not primarily an antioxidant but rather a coenzyme involved in energy metabolism. Choice C is incorrect because vitamin B1 is not required for the synthesis of prothrombin or clotting factors. Choice D is incorrect because flavoproteins, FMN, and FAD are associated with vitamin B2 (riboflavin), not vitamin B1.

Correct Answer: A

Rationale: The correct answer is A: TRUE. Probufol can stay in the body for a long time, and waiting 6 months after stopping the medication before becoming pregnant is crucial to prevent potential harm to the fetus. This waiting period allows the drug to be eliminated from the body, reducing the risk of any adverse effects on the pregnancy. Choice B (FALSE) is incorrect because it is important for women to wait before becoming pregnant after stopping probucol therapy. Choices C (All) and D (None) are also incorrect as they do not accurately represent the specific guideline related to probucol use and pregnancy.

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.