Choose the characteristics of chloramphenicol:

Correct Answer: D

Rationale: The correct answer is D because Chloramphenicol is a broad-spectrum antibiotic that inhibits protein synthesis in bacteria, making it bacteriostatic. It affects both Gram-positive and Gram-negative microorganisms. Choice A is incorrect because chloramphenicol is bacteriostatic, not bactericidal. Choice B is incorrect because it influences both Gram-positive and Gram-negative bacteria. Choice C is incorrect because it also influences both types of bacteria and it is bacteriostatic, not bactericidal.

Correct Answer: A

Rationale: The correct answer is A: Didanosine. Nucleoside reverse transcriptase inhibitors (NRTIs) are a class of antiretroviral drugs used to treat HIV/AIDS. Didanosine is an NRTI that inhibits the reverse transcriptase enzyme, crucial for HIV replication. Gancyclovir is a nucleoside analog used to treat viral infections but not specifically NRTIs. Nevirapine is a non-nucleoside reverse transcriptase inhibitor. Vidarabine is a nucleoside analog antiviral drug, but it is not classified as an NRTI. Overall, only Didanosine belongs to the NRTI class of drugs.

Correct Answer: C

Rationale: The correct answer is C: Decreased myocardial remodeling. Beta-blockers decrease the workload of the heart by reducing heart rate and contractility, which in turn decreases myocardial oxygen demand and reduces the risk of further damage to the heart muscle post-myocardial infarction. This leads to a decrease in adverse remodeling of the heart, improving overall cardiac function and reducing mortality. Incorrect Choices: A: Increased myocardial oxygen supply - Beta-blockers do not directly increase myocardial oxygen supply but rather decrease oxygen demand. B: Decreased atrioventricular conduction - While beta-blockers can slow atrioventricular conduction, this is not the primary mechanism for mortality reduction in myocardial infarction. D: Increased systemic vascular resistance - Beta-blockers actually decrease systemic vascular resistance, which can be beneficial in certain conditions but is not the primary reason for mortality reduction in myocardial infarction.

Correct Answer: B

Rationale: The correct answer is B: Propranolol. Propranolol is a beta-blocker that can be used for rate control in atrial fibrillation. It works by blocking the effects of adrenaline on the heart, slowing the heart rate and reducing the force of contraction. In this case, the patient has atrial fibrillation with a rapid ventricular response, and propranolol can help slow the heart rate to a more appropriate level. A: Digoxin is primarily used for rate control in patients with heart failure, not as the first-line agent for atrial fibrillation with a rapid ventricular response. C: Verapamil is a calcium channel blocker that can also be used for rate control in atrial fibrillation, but beta-blockers are generally preferred in patients with concomitant peripheral artery disease. D: Lidocaine is a local anesthetic and antiarrhythmic agent used for ventricular arrhythmias, not appropriate for atrial fibrillation.

Correct Answer: B

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