Nokea
Which of the following best describes the mechanism of action of alprostadil?
- A. Alprostadil increases cAMP
- B. Alprostadil increases cGMP
- C. Alprostadil increases PDE-5
- D. Alprostadil blocks NO (nitric oxide)
Correct Answer: A
Rationale: Alprostadil is a prostaglandin E1 analog that works by binding to specific receptors and activating adenylate cyclase, leading to increased levels of cAMP. This results in smooth muscle relaxation and vasodilation. Therefore, choice A is correct. Choices B and C are incorrect as alprostadil does not directly affect cGMP levels or PDE-5 activity. Choice D is also incorrect as alprostadil does not block nitric oxide, but rather enhances its effects through the cAMP pathway.
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Which of the following activities is not related to kidney function?
- A. control of hydrogen ion and pH in the blood
- B. control of wastes in the blood
- C. lipid digestion
- D. regulation of blood pressure
Correct Answer: C
Rationale: The correct answer is C: lipid digestion. Kidneys are not involved in the process of lipid digestion. Kidneys primarily function in filtering blood, controlling water and electrolyte balance, regulating blood pressure, and removing waste products. Lipid digestion occurs in the gastrointestinal system, specifically in the small intestine, where bile from the liver aids in breaking down fats. Choices A, B, and D are all functions directly related to kidney function, as the kidneys play a crucial role in maintaining proper pH balance, filtering waste products from the blood, and regulating blood pressure.
Cloxacillin is indicated in infections caused by the following organism(s):
- A. Staphylococci
- B. Streptococci
- C. Gonococci
- D. All of the above
Correct Answer: A
Rationale: Cloxacillin is a beta-lactam antibiotic effective against Staphylococci. Staphylococci commonly cause skin and soft tissue infections. Streptococci are not typically treated with cloxacillin. Gonococci are not susceptible to cloxacillin. Therefore, the correct answer is A, as it is the only organism listed that is indicated for treatment with cloxacillin.
During an examination, the nurse notices that a male patient has a red, round, superficial ulcer with a yellowish serous discharge on his penis. On palpation, the nurse finds a nontender base that feels like a small button between the thumb and fingers. At this point the nurse suspects that this patient has:
- A. COM
- B. Genital warts.
- C. Herpes infection.
- D. Syphilitic chancr
Correct Answer: D
Rationale: The correct answer is D: Syphilitic chancre. The description of a red, round, superficial ulcer with a yellowish serous discharge on the penis, along with a nontender base that feels like a small button, is indicative of a primary syphilitic chancre. This lesion is typically painless and can be mistaken for other genital ulcers, but the specific characteristics described point towards syphilis. Genital warts (choice B) present as cauliflower-like growths, herpes infection (choice C) typically causes painful blisters, and chancroid (choice A) is characterized by soft, painful ulcers. Syphilitic chancre is the most likely diagnosis based on the presentation described.
Which antibiotic is primarily bacteriostatic but becomes bactericidal at higher concentrations?:
- A. Erythromycin
- B. Tetracycline
- C. Chloramphenicol
- D. Ampicillin
Correct Answer: A
Rationale: Erythromycin is primarily bacteriostatic by inhibiting protein synthesis in bacteria. At higher concentrations, it can disrupt bacterial cell membranes, making it bactericidal. Tetracycline inhibits protein synthesis, Chloramphenicol blocks peptide bond formation, and Ampicillin disrupts bacterial cell wall synthesis. Therefore, A is correct because of its dual mechanism of action.
Which of the following drug which directly inhibits HIV-reverse transcriptase * without the need for intracellular activation by phosphorylation:
- A. Nelnavir
- B. Nevirapine
- C. Stavudine
- D. Didanosine
Correct Answer: B
Rationale: The correct answer is B: Nevirapine. Nevirapine is a non-nucleoside reverse transcriptase inhibitor (NNRTI) that directly inhibits HIV-reverse transcriptase without needing intracellular activation. It binds directly to the enzyme's active site, preventing the conversion of viral RNA to DNA.
Rationale:
1. Nelnavir (A) is a protease inhibitor that works by blocking the protease enzyme needed for viral replication, not reverse transcriptase inhibition.
2. Stavudine (C) and Didanosine (D) are nucleoside reverse transcriptase inhibitors (NRTIs) that require intracellular phosphorylation to become active, unlike Nevirapine.
In summary, Nevirapine is the correct answer as it directly inhibits HIV-reverse transcriptase without needing intracellular activation, distinguishing it from the other choices which belong to different drug classes or require intracellular phosphorylation.