Choose the drug belonging to membranestabilizing agents:

Correct Answer: B

Rationale: The correct answer is B: Sodium cromoglycate. Membrane-stabilizing agents stabilize cell membranes and prevent the release of inflammatory mediators. Sodium cromoglycate is a mast cell stabilizer that works by inhibiting the release of histamine and other inflammatory substances. Zileutin (A) is a 5-lipoxygenase inhibitor, Zafirlucast (C) and Montelukast (D) are leukotriene receptor antagonists, which work by blocking the action of leukotrienes, not by stabilizing cell membranes.

Correct Answer: B

Rationale: The correct answer is B. ACE inhibitors do not increase plasma cholesterol levels. ACE inhibitors improve hemodynamics by decreasing afterload, slow the progression of heart failure by preventing myocardial remodeling, and reduce secretion of aldosterone. Choice A is correct because ACE inhibitors reduce systemic vascular resistance, decreasing afterload. Choice C is correct because ACE inhibitors can prevent myocardial remodeling and slow the progression of heart failure. Choice D is correct because ACE inhibitors can reduce aldosterone secretion, leading to decreased sodium and water retention. Therefore, the incorrect statement among the choices is B.

Correct Answer: B

Rationale: The correct answer is B: Clonidine. Clonidine acts on vasomotor centers in the central nervous system (CNS) by stimulating alpha-2 adrenergic receptors, leading to decreased sympathetic outflow, resulting in reduced peripheral vascular resistance and ultimately lowering blood pressure. Labetalol (A) is a non-selective beta and alpha blocker, Enalapril (C) is an ACE inhibitor, and Nifedipine (D) is a calcium channel blocker, all of which work by different mechanisms to reduce blood pressure compared to Clonidine.

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: C

Rationale: The correct answer is C: All of the above. Recombinant DNA techniques involve inserting the proinsulin gene into E. coli or yeast to produce human insulin. This is a common method used in commercial insulin production. Postmortem insulin extraction from human autopsy pancreas is also a valid source of human insulin, although it is less common due to ethical and practical considerations. Therefore, both A and B are valid sources of human insulin production, making option C the correct choice. Option D is incorrect because we have established that both A and B are valid methods for human insulin production.