The patient in a long arm cast (from below the shoulder to the wrist, with a 90-degree elbow flexion) complains of a burning sensation over the elbow. The nurse's initial intervention should be:

Correct Answer: B

Rationale: The correct answer is B: Check to see if the cast is properly supported. The burning sensation over the elbow could indicate nerve compression due to improper cast positioning. By checking if the cast is properly supported, the nurse can ensure that there is no pressure on the nerves causing the burning sensation. Elevating the casted arm (choice A) may not address the root cause of the burning sensation. Notifying the charge nurse of developing pressure ulcer (choice C) is premature without confirming the cause of the burning sensation. Cutting a "window" in the cast (choice D) should be a last resort after ruling out other issues.

Correct Answer: a

Rationale: The correct answer is A: Mediated by IgE. Leishmania infection is not primarily mediated by IgE antibodies. The immune response against Leishmania involves T cells, macrophages, and cytokines. IgE is not a major player in the defense against Leishmania. Choices B, C, and D are incorrect because Leishmania is indeed a unicellular parasite, activation of macrophages is essential for killing the parasite, and Leishmania can hide inside neutrophils to escape the host immune attack.

Correct Answer: A

Rationale: Rationale: A. T regulatory cells can produce TGF-β, which is a key immunosuppressive cytokine regulating immune responses. B. T regulatory cells do not express AIRE, a transcription factor mainly involved in central tolerance. C. T regulatory cells can control both TH1 and TH2 responses, maintaining immune homeostasis. D. T regulatory cells do not act by killing other T cell subsets, but rather through suppressive cytokines and cell-cell interactions.

Correct Answer: A

Rationale: The correct answer is A. Integration is a stage of HIV life cycle that involves the insertion of viral DNA into the host cell's genome, facilitated by the enzyme integrase. To explain why A is incorrect, integrase is a viral enzyme, not a host enzyme. B is correct as some anti-HIV drugs target the integration stage to prevent viral replication. C is correct as integrated proviral DNA allows for duplication during cell division. D is correct as integration requires the formation of double-stranded viral DNA.

Correct Answer: C

Rationale: The correct answer is C: Natural killer cells. Natural killer cells are part of the innate immune system and play a crucial role in identifying and destroying infected or abnormal cells. They are able to recognize and target cells that lack specific markers, providing a rapid response to infections. Explanation for incorrect choices: A: B lymphocytes are part of the adaptive immune system, not innate immunity. B: T lymphocytes are also part of the adaptive immune system, not involved in innate immunity. D: Plasma cells are differentiated B cells that produce antibodies in the adaptive immune response, not part of innate immunity.