Tolerance to this inotropic drug develops after a few days:

Correct Answer: C

Rationale: Rationale: 1. Dobutamine is a beta-1 adrenergic receptor agonist used as an inotropic drug. 2. Continuous use of dobutamine leads to receptor desensitization, causing tolerance. 3. Tolerance develops within a few days due to downregulation of beta-1 receptors. 4. Amrinone and amiodarone are not inotropic drugs and do not cause tolerance. 5. Adenosine is not an inotropic drug and has a rapid onset and short duration of action.

Correct Answer: B

Rationale: The correct answer is B: Vasoconstrictors. Vasoconstrictors are used to increase blood pressure in chronic hypotension by constricting blood vessels, thus raising blood pressure. Positive inotropic drugs (A) increase the strength of the heart's contractions, which is not the primary concern in hypotension. Plasmoexpanders (C) are used to increase blood volume, not necessarily blood pressure. Analeptics and tonics (D) are more commonly used for conditions like fatigue or depression, not specifically for chronic hypotension.

Correct Answer: A

Rationale: The correct answer is A: Elderly patients (over 45 years). Radioiodines are suitable for elderly patients due to their slower metabolism, which allows for better uptake and retention of the radioiodine in the thyroid gland. This results in more effective treatment of conditions like hyperthyroidism or thyroid cancer. Pregnant women, nursing mothers, and younger patients should avoid radioiodine therapy due to potential risks to the fetus, infant, and developing thyroid gland, respectively. Overall, the slower metabolism in elderly patients makes them the most suitable candidates for radioiodine therapy.

Correct Answer: A

Rationale: Rationale: 1. During acute inflammation, the initial response is vasodilation and increased capillary permeability. 2. This leads to increased blood flow, redness, heat, and swelling at the site of injury. 3. The purpose is to deliver immune cells and proteins to the affected area to fight off pathogens. 4. Infiltration of leukocytes and phagocytic cells occurs after vasodilation in the exudation phase. 5. Tissue degeneration and fibrosis occur in the later stages of chronic inflammation, not in the acute phase. 6. Choice A is correct as it specifically describes the characteristics of the acute, transient phase of inflammation. Summary: - Choice A is correct as it accurately describes the characteristics of acute inflammation. - Choices B, C, and D are incorrect as they describe phases or processes that occur in chronic inflammation or are not specific to the acute phase.

Correct Answer: B

Rationale: The correct answer is B because H2 histamine receptor subtype is mainly distributed in gastric mucosa, cardiac muscle, mast cells, and brain. This receptor subtype plays a crucial role in gastric acid secretion and cardiovascular functions. Choice A is incorrect because smooth muscle and endothelium are primarily associated with H1 receptors, not H2 receptors. Choice C is incorrect because presynaptic H3 receptors are found in the brain and other neurons, not H2 receptors. Choice D is incorrect because H2 receptors are not distributed in smooth muscle, endothelium, or presynaptic regions as mentioned in choices A and C.