What is the main action of GABA derivatives in disorders of brain circulation?

Correct Answer: B

Rationale: The correct answer is B: Stimulation of the metabolic processes in neurons. GABA derivatives act by enhancing neuronal metabolism, which helps improve brain circulation and function. This action supports the neurons' energy production and overall function. A: Decrease of vessel permeability is incorrect because GABA derivatives do not directly affect vessel permeability in brain circulation disorders. C: Brain vessel constriction is incorrect as GABA derivatives do not cause constriction of brain vessels but rather support neuronal function. D: Intracranial pressure increase is incorrect as GABA derivatives do not lead to an increase in intracranial pressure; instead, they support neuronal metabolic processes.

Correct Answer: B

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: B

Rationale: Step-by-step rationale for choice B (Cyproheptadine) as the correct answer: 1. Cyproheptadine is a potent H1 receptor antagonist. 2. It is also known for its significant serotonin-blocking effect. 3. This dual mechanism of action makes it effective for treating conditions involving both histamine and serotonin imbalances. 4. Brompheniramine (A), Suprastine (C), and Dimedrol (D) do not exhibit significant serotonin-blocking effects, making them incorrect choices.

Correct Answer: A

Rationale: The correct answer is A: Extreme dryness of the conjunctiva resulting from a disease localized in the eye or from systemic deficiency of vitamin A. Xerophthalmia refers to extreme dryness of the eyes due to vitamin A deficiency. It affects the conjunctiva, leading to dry eyes. This condition can be localized in the eye or due to systemic deficiency of vitamin A. Choice B is incorrect because it describes a condition known as keratomalacia, which involves softening, ulceration, and perforation of the cornea, not extreme dryness of the conjunctiva. Choice C is also incorrect as it describes night blindness, a condition where vision is weak in dim light due to vitamin A deficiency, not extreme dryness of the conjunctiva. Choice D is incorrect because it includes all the statements, but xerophthalmia specifically refers to extreme dryness of the conjunctiva due to vitamin A deficiency, not the other conditions mentioned.

Correct Answer: A

Rationale: Hypercholesterolemia is indeed an abnormally high concentration of cholesterol in the blood, making choice A true. Choice B is incorrect as hypercholesterolemia is a recognized medical condition. Choice C, stating "All," is incorrect as it is too vague and does not provide a clear answer. Choice D, stating "None," is also incorrect because hypercholesterolemia is a valid medical term and condition.