Nokea
Many immune cells listed below are found in the absence of infection in the lamina propria of the gut with the exception of:
- A. Neutrophils
- B. Macrophages
- C. Plasma cells
- D. T cells
Correct Answer: A
Rationale: Neutrophils are typically not found in the lamina propria of the gut in the absence of infection because they are primarily involved in the acute inflammatory response to infections. Macrophages, plasma cells, and T cells are commonly present in the gut lamina propria to maintain immune homeostasis and respond to antigens. Neutrophils are more abundant in tissues during active infection due to their role in phagocytosis and inflammation. Therefore, the correct answer is A: Neutrophils.
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What are the recommended measures to prevent the transmission of health care–associated infections (HAIs) (select all that apply)?
- A. Empty bedpans as soon as possible
- B. Use personal protective equipment
- C. Hand washing or alcohol-based sanitizing
- D. Have patients wear sandals in the shower
Correct Answer: B
Rationale: The correct answer includes options B and C. Using personal protective equipment and practicing proper hand hygiene are critical measures to prevent HAIs. Emptying bedpans promptly and having patients wear sandals in the shower are not directly related to preventing HAIs.
A cell type capable of killing virus-infected cells that provides early protection against viral infection is
- A. Eosinophils
- B. NK cells
- C. Neutrophils
- D. Mast cells
Correct Answer: B
Rationale: The correct answer is B: NK cells. NK cells are part of the innate immune system and can directly kill virus-infected cells, providing early protection against viral infections. They do not require prior exposure to the virus to initiate their killing mechanism, making them crucial for early defense. Eosinophils (A), Neutrophils (C), and Mast cells (D) are not primarily involved in killing virus-infected cells. Eosinophils are more associated with parasitic infections, Neutrophils are primarily involved in bacterial infections, and Mast cells are involved in allergic reactions.
Viral antigenic shift
- A. Is caused by multiple random mutations
- B. Is caused by a single mutation
- C. It affects only internal viral proteins not recognized by preexisting antibodies
- D. It refers to the appearance of new HA variants not recognized by preexisting antibodies
Correct Answer: D
Rationale: Step 1: Viral antigenic shift involves major changes in the surface proteins of the virus, particularly the hemagglutinin (HA) protein.
Step 2: These changes result in the emergence of new variants that are not recognized by preexisting antibodies.
Step 3: This process is distinct from antigenic drift, which involves minor changes due to random mutations.
Step 4: Choice D correctly states that viral antigenic shift refers to the appearance of new HA variants not recognized by preexisting antibodies.
Summary: Choice A is incorrect because viral antigenic shift is not caused by multiple random mutations. Choice B is incorrect as antigenic shift involves major changes, not a single mutation. Choice C is incorrect as it affects surface proteins like HA, not just internal proteins.
An HIV-positive patient who has been started on antiretroviral therapy (ART) is seen in the clinic for follow-up. Which test will be most helpful in determining the response to therapy?
- A. Lymphocyte count
- B. ELISA testing
- C. Western blot analysis
- D. Viral load testing
Correct Answer: D
Rationale: Viral load testing measures the amount of HIV RNA in the blood and is the most direct way to assess the effectiveness of antiretroviral therapy. A decrease in viral load indicates that the therapy is working. The other tests provide useful information but are not as directly related to the effectiveness of ART.
What type of cell is responsible for carrying oxygen and carbon dioxide in the body?
- A. Red blood cell
- B. White blood cell
- C. Platelet
- D. Hematocrit
Correct Answer: A
Rationale: The correct answer is A: Red blood cell. Red blood cells, also known as erythrocytes, contain hemoglobin that binds to oxygen and carbon dioxide for transport in the bloodstream. They are specifically designed for gas exchange. White blood cells (B) are part of the immune system and fight infections. Platelets (C) are responsible for blood clotting. Hematocrit (D) refers to the proportion of red blood cells in the blood, not a specific type of cell responsible for gas transport.