Nokea
L-Selectin is
- A. Expressed on effector T cells
- B. Expressed on HEV
- C. Expressed on naïve T cells
- D. Required to extravasate into tissues
Correct Answer: C
Rationale: The correct answer is C: Expressed on naïve T cells. L-Selectin is a cell adhesion molecule expressed on the surface of naïve T cells. It plays a crucial role in the initial attachment of T cells to high endothelial venules (HEV) in lymphoid tissues, facilitating T cell entry into lymph nodes. It specifically binds to ligands on HEV, allowing T cells to extravasate into lymphoid tissues. Choice A is incorrect because L-Selectin is primarily expressed on naïve T cells rather than effector T cells. Choice B is incorrect as L-Selectin is expressed on HEV, not by them. Choice D is incorrect because L-Selectin is involved in the initial attachment of T cells to endothelial cells, rather than being required for extravasation into tissues.
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Prophylactic measures that are routinely used as early as possible in HIV infection to prevent opportunistic and debilitating secondary problems include administration of
- A. isoniazid (INH) to prevent tuberculosis
- B. trimethoprim/sulfamethoxazole (TMP/SMX) for toxoplasmosis
- C. vaccines for pneumococcal pneumonia, influenza, and hepatitis A and B
- D. varicella-zoster immune globulin (VZIG) to prevent chickenpox or shingles
Correct Answer: C
Rationale: Vaccination protects against preventable infections that can become severe in immunocompromised individuals.
In a patient with leukocytosis with a shift to the left, what does the nurse recognize as causing this finding?
- A. The complement system has been activated to enhance phagocytosis.
- B. Monocytes are released into the blood in larger-than-normal amounts.
- C. The response to cellular injury is not adequate to remove damaged tissue and promote healing.
- D. The demand for neutrophils causes the release of immature neutrophils from the bone marrow.
Correct Answer: D
Rationale: A 'shift to the left' refers to an increase in immature neutrophils in circulation, which occurs when there is a high demand for neutrophils due to infection or inflammation. This phenomenon indicates that the bone marrow is releasing immature neutrophils to meet the body's needs.
What structure is recognized by TLR4 in mammals?
- A. Peptidoglycan
- B. Lipopolysaccharide (LPS)
- C. Double-stranded RNA
- D. Mannose-binding lectin
Correct Answer: B
Rationale: The correct answer is B: Lipopolysaccharide (LPS). TLR4 recognizes LPS, a component of the outer membrane of Gram-negative bacteria, triggering an immune response. This recognition is crucial in detecting bacterial infections. Peptidoglycan (A) is recognized by other TLRs, not TLR4. Double-stranded RNA (C) is recognized by TLR3, not TLR4. Mannose-binding lectin (D) is a pattern recognition receptor that binds to carbohydrate structures, not specifically recognized by TLR4.
Smack' is a drug obtained from the:
- A. latex of Papaver somniferum
- B. leaves of Cannabis sativa
- C. flowers of Dhatura
- D. fruits of Erythroxylum coca
Correct Answer: A
Rationale: The correct answer is A. Smack is a street name for heroin, which is derived from the latex of Papaver somniferum, commonly known as the opium poppy. The latex of this plant contains morphine and codeine, which are the main components of heroin. Cannabis sativa (B) refers to marijuana, not smack. Dhatura (C) and Erythroxylum coca (D) are sources of other drugs like scopolamine and cocaine, respectively, not heroin. Therefore, A is the correct answer as it corresponds to the actual source of smack/heroin.
A patient prescribed corticosteroids for arthritis is surprised to learn of an immune disorder. What should the nurse explain as the reason for the patient not demonstrating typical signs of immune dysfunction?
- A. The arthritis is masking the normal immune response.
- B. The corticosteroids are causing the thymus gland to malfunction.
- C. The arthritis is interfering with the function of immunoglobulins.
- D. Corticosteroids are impacting normal immune response functioning.
Correct Answer: D
Rationale: The correct answer is D because corticosteroids are known to suppress the immune system by inhibiting the production of pro-inflammatory cytokines and preventing the activation of immune cells. This suppression can lead to a decreased immune response, making it less likely for the patient to exhibit typical signs of immune dysfunction.
A: The arthritis masking the immune response is not a plausible explanation as arthritis does not directly affect immune function.
B: Corticosteroids do not cause the thymus gland to malfunction; they mainly impact immune response at the cellular level.
C: Arthritis affecting immunoglobulin function is not a common mechanism of immune dysfunction in this context.