Nokea
Which classification of chemotherapy drugs is cell cycle phase–nonspecific, breaks the DNA helix which interferes with DNA replication, and crosses the blood-brain barrier?
- A. Nitrosureas
- B. Antimetabolites
- C. Mitotic inhibitors
- D. Antitumor antibiotics
Correct Answer: A
Rationale: Nitrosureas are cell cycle phase–nonspecific, disrupt DNA replication, and cross the blood-brain barrier.
You may also like to solve these questions
What was the important contribution to microbiology of Anton Van Leeuwenhoek in the 1600s?
- A. He was the first to observe microorganisms
- B. He disproved the theory of spontaneous generation of microorganisms
- C. He was the first to show that a disease could be caused by a microorganism
- D. He was the first to describe the process of fermentation
Correct Answer: A
Rationale: The correct answer is A: He was the first to observe microorganisms. Van Leeuwenhoek's important contribution to microbiology was his discovery of microorganisms using his own handcrafted microscopes. This observation revolutionized the field by providing the first direct evidence of the existence of microorganisms.
Choice B is incorrect because Leeuwenhoek's observations actually supported the idea of spontaneous generation. Choice C is incorrect because he did not link microorganisms to diseases. Choice D is incorrect because the process of fermentation was described by others before Leeuwenhoek.
What antibody mediates Type I hypersensitivity?
- A. IgA
- B. IgE
- C. IgG
- D. IgM
Correct Answer: B
Rationale: The correct answer is B: IgE. In Type I hypersensitivity reactions, IgE antibodies are involved. Firstly, upon initial exposure to an allergen, B cells produce IgE antibodies specific to that allergen. IgE antibodies then bind to mast cells and basophils. Upon subsequent exposure to the same allergen, it cross-links the IgE antibodies on mast cells and basophils, leading to degranulation and release of inflammatory mediators like histamine. This results in the symptoms of Type I hypersensitivity reactions.
Choice A (IgA) is incorrect because IgA is mainly involved in mucosal immunity. Choice C (IgG) is incorrect because while IgG can be involved in Type II and Type III hypersensitivity reactions, it is not the primary antibody in Type I hypersensitivity. Choice D (IgM) is incorrect because IgM is typically involved in the primary immune response, not in Type I hypersensitivity reactions.
Priority Decision: On assessment of a central venous access device (CVAD) site, the nurse observes that the transparent dressing is loose along two sides. What should the nurse do immediately?
- A. Wait and change the dressing when it is due
- B. Tape the two loose sides down and document
- C. Apply a gauze dressing over the transparent dressing and tape securely
- D. Remove the dressing and apply a new transparent dressing using sterile technique
Correct Answer: D
Rationale: Loose dressings increase infection risk; replacing the dressing with sterile technique ensures safety.
Attenuated vaccines can be obtained by
- A. Passage through cultured cells
- B. Formaldehyde treatment
- C. The use of viral vectors carrying pathogen subunits
- D. All of the above treatments would lead to attenuated vaccines
Correct Answer: A
Rationale: The correct answer is A: Passage through cultured cells. Attenuated vaccines are produced by weakening the pathogen through serial passages in cultured cells, reducing virulence while maintaining immunogenicity. Formaldehyde treatment (B) disrupts the pathogen's structure and is used for inactivated vaccines. The use of viral vectors carrying pathogen subunits (C) is a method for creating subunit vaccines, not attenuated vaccines. Therefore, D is incorrect as not all treatments lead to attenuated vaccines.
The patient is experiencing fibrosis and glomerulopathy a year after a kidney transplant. Which type of rejection is occurring?
- A. Acute
- B. Chronic
- C. Delayed
- D. Hyperacute
Correct Answer: B
Rationale: Chronic rejection occurs over time and involves fibrosis and structural changes in the transplanted organ.