Which of the following vitamins is also known as an antisterility factor?

Correct Answer: A

Rationale: The correct answer is A: Vitamin E. Vitamin E is known as the antisterility factor because it plays a crucial role in fertility and reproduction. It helps protect reproductive organs and improve fertility in both men and women. Vitamin B6 (choice B) is important for metabolism but not specifically related to fertility. Vitamin B1 (choice C) is essential for energy production but not known as an antisterility factor. Vitamin K (choice D) is important for blood clotting and bone health, not fertility. Thus, the correct answer is Vitamin E due to its specific role in promoting fertility and reproductive health.

Correct Answer: D

Rationale: The correct answer is D: Elevated skeletal turnover. 1,25-dihydroxyvitamin D3 (calcitriol) is administered for hypocalcemia in chronic renal failure, vitamin D-dependent rickets, and malabsorption of vitamin D. Elevated skeletal turnover is not an indication for calcitriol as it can exacerbate bone resorption. Administering calcitriol in such cases can lead to increased calcium release from bones and worsen the condition. Therefore, D is the correct answer.

Correct Answer: D

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

Correct Answer: B

Rationale: The correct answer is B: Macrolides. Macrolides exert a bacteriostatic effect by inhibiting bacterial protein synthesis. They do not directly kill bacteria but rather prevent their growth and reproduction. Carbapenems (A), aminoglycosides (C), and cephalosporins (D) are examples of antibiotics that typically exhibit bactericidal effects, meaning they directly kill bacteria. Therefore, Macrolides are the only group among the options that demonstrate a bacteriostatic effect.

Correct Answer: B

Rationale: Rationale: Trimethoprim inhibits dihydropteroate reductase, an enzyme in the folate synthesis pathway in bacteria, disrupting DNA and protein synthesis. This leads to bacterial cell death. Cyclooxygenase (Choice A) is targeted by NSAIDs, not trimethoprim. Dihydropteroate synthase (Choice C) is targeted by sulfonamides, not trimethoprim. DNA gyrase (Choice D) is targeted by fluoroquinolones, not trimethoprim. Therefore, Choice B is correct for trimethoprim's mechanism of action.