This drug inhibits breakdown of cAMP in vascular smooth muscle:

Correct Answer: C

Rationale: Amrinone inhibits breakdown of cAMP by inhibiting phosphodiesterase enzyme in vascular smooth muscle. This leads to increased cAMP levels, causing vasodilation. Digoxin, dobutamine, and dopamine have no direct effect on cAMP breakdown in vascular smooth muscle. Digoxin increases intracellular calcium, dobutamine is a beta-adrenergic agonist, and dopamine acts on dopamine receptors.

Correct Answer: D

Rationale: The correct answer is D because all the listed drug groups influence cerebral blood flow. Ca-channel blockers dilate blood vessels, enhancing cerebral perfusion. GABA derivatives can modulate blood flow by affecting neurotransmission. Vinca minor derivatives like vincamine can improve cerebral circulation. Therefore, all choices have a direct impact on cerebral flow, making D the correct answer.

Correct Answer: A

Rationale: The correct answer is A: Radioiodines in the body emit mainly β radiations. This is because radioiodines typically decay by β- decay, releasing β particles. β radiation consists of electrons or positrons, which are emitted during the decay process. This type of radiation is commonly observed with radioiodines. Option B is incorrect because γ radiation is a type of electromagnetic radiation emitted by the nucleus, not by radioiodines in this case. Option C is incorrect because radioiodines predominantly emit β radiation, not an equal amount of β and γ. Option D is incorrect because radioiodines do emit radiation, particularly β radiation, and therefore are not completely safe in terms of radiation exposure.

Correct Answer: B

Rationale: The correct answer is B: Infiltration of leucocytes and phagocytic cells (phase of exudation). During the delayed, subacute phase of inflammation, infiltrating leukocytes, such as neutrophils and macrophages, play a crucial role in removing debris and pathogens. This phase is characterized by the migration of these cells to the site of injury, where they engulf and digest foreign substances. This process helps to clear the area of infection and promote tissue repair. Other choices are incorrect: A: Local vasodilatation and increased capillary permeability (phase of damage) - This describes the initial phase of inflammation, not the delayed subacute phase. C: Tissue degeneration and fibrosis occurrence (phase of proliferation) - This describes the later stages of inflammation involving tissue repair and remodeling, not the delayed subacute phase. D: All of the above - This is incorrect as choices A and C do not accurately describe the delayed, subacute

Correct Answer: A

Rationale: The correct answer is A: Granules in mast cells or basophils. Mast cells and basophils are well-known for storing histamine in their granules. Upon stimulation, these cells release histamine into the surrounding tissues. Histaminergic neurons (choice B) primarily release histamine in the brain and are not the main reservoir of tissue histamine. Enterochromaffin-like cells (choice C) are found in the stomach and release histamine into the bloodstream, not sequestering it in tissues. Therefore, the correct choice is A as most tissue histamine is indeed sequestered and bound in granules in mast cells or basophils.