A patient in Russell traction with a Pearson attachment for a fracture of the tibia complains of intense pain at the fracture site. The nurse assesses a temperature of 102° F and increased swelling at the fracture site. Which complication do these findings suggest?

Correct Answer: A

Rationale: The correct answer is A: Osteomyelitis. The combination of intense pain, increased swelling, elevated temperature, and presence of traction indicates an infection in the bone, suggesting osteomyelitis. This serious complication requires prompt treatment with antibiotics. Incorrect choices: B: Fat embolism - This typically presents with respiratory distress, petechiae, and neurological changes, not with localized pain and swelling. C: Traction misalignment - This would cause a change in the alignment of the fracture but would not typically present with fever and localized signs of infection. D: Nonunion of the fracture - Nonunion is a failure of the bone to heal, which would not typically present with the acute signs of infection seen in this case.

Correct Answer: A

Rationale: The correct answer is A: HEV (High Endothelial Venules). PNAd is a ligand expressed on high endothelial venules, which helps in the recruitment of lymphocytes from the bloodstream into secondary lymphoid organs. PNAd is not primarily expressed on lymphocytes themselves (B) or dendritic cells (C). While PNAd can be involved in thymocyte migration to the thymus, it is not expressed on the thymus itself (D). Thus, the correct answer is A as it directly relates to the function and location of PNAd expression.

Correct Answer: C

Rationale: Step-by-step rationale for why choice C (Anti-TNF-α) is correct: 1. Anti-TNF-α drugs target specific molecules involved in autoimmune responses. 2. By inhibiting TNF-α, these drugs reduce inflammation and slow disease progression. 3. This makes them disease-modifying, as they alter the course of the autoimmune disease. Summary of why other choices are incorrect: A: Corticosteroids are anti-inflammatory but not disease-modifying in autoimmune diseases. B: Aspirin is primarily used for pain relief and reducing inflammation, not modifying the disease. D: C-cell depleting agents are not commonly used for autoimmune diseases and do not target TNF-α.

Correct Answer: C

Rationale: The correct answer is C: gp120. This is because gp120 is a key HIV antigen that plays a crucial role in binding to CD4 receptors on T cells, facilitating viral entry. By targeting gp120, vaccines can induce antibodies that block this interaction, preventing HIV from infecting CD4+ T cells. Conversely, choices A, B, and D (gp41, Reverse transcriptase, Matrix proteins) are not as effective targets for interfering with the CD4+ T cell interaction, as they do not directly impact the initial binding and entry process of HIV into the cells.

Correct Answer: C

Rationale: The correct answer is C: TNF-alpha and TNF-beta. Tumor necrosis factors (TNF) are a specific category of cytokines known for their role in promoting inflammation and inducing cell death in tumor cells. TNF-alpha and TNF-beta are two key members of this cytokine category. Interleukins (choice A) are a different group of cytokines involved in immune responses. Interferons (choice B) are cytokines that help regulate the immune system's response to viral infections. TGF-beta (choice D) is a cytokine involved in regulating cell growth and differentiation, but not specifically associated with tumor necrosis factors.