AIRE is expressed in
- A. Bone marrow
- B. Thymic cortical region
- C. Thymic medullary region
- D. LN cortex
Correct Answer: C
Rationale: The correct answer is C: Thymic medullary region. AIRE (Autoimmune Regulator) is expressed in the thymic medullary region. This region is crucial for central tolerance by deleting self-reactive T cells to prevent autoimmune reactions. AIRE regulates the expression of tissue-specific antigens in medullary thymic epithelial cells, leading to negative selection of autoreactive T cells. Choices A, B, and D are incorrect as AIRE is not primarily expressed in bone marrow, thymic cortical region, or LN cortex.
You may also like to solve these questions
A naïve lymphocyte:
- A. Does not yet express antigen receptors
- B. Is not yet considered mature
- C. Has not yet been activated by antigen
- D. Is found only in primary lymphoid tissues
Correct Answer: C
Rationale: Step-by-step rationale:
1. Naïve lymphocytes have antigen receptors but have not been activated by antigen.
2. Activation is necessary for their differentiation into effector cells.
3. Naïve lymphocytes are considered mature as they have completed development.
4. They circulate in secondary lymphoid tissues, not just primary lymphoid tissues.
Summary:
Choice C is correct because naïve lymphocytes have antigen receptors but have not been activated by antigen. Choices A, B, and D are incorrect because naïve lymphocytes do express antigen receptors, are considered mature, and can be found in both primary and secondary lymphoid tissues.
What is a characteristic feature of Goodpasture's syndrome?
- A. Granuloma formation
- B. Pulmonary hemorrhage and glomerulonephritis
- C. Contact dermatitis
- D. Bronchoconstriction and vasodilation
Correct Answer: B
Rationale: The correct answer is B: Pulmonary hemorrhage and glomerulonephritis. Goodpasture's syndrome is an autoimmune disease characterized by the presence of anti-glomerular basement membrane antibodies, leading to damage in the kidneys (glomerulonephritis) and lungs (pulmonary hemorrhage). Granuloma formation (A), contact dermatitis (C), and bronchoconstriction and vasodilation (D) are not characteristic features of Goodpasture's syndrome. Granulomas are more commonly seen in conditions like sarcoidosis, contact dermatitis is an inflammatory skin condition, and bronchoconstriction and vasodilation are features of allergic reactions or asthma, not typically seen in Goodpasture's syndrome.
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.
What is the outcome of clonal selection after a lymphocyte is activated?
- A. Cytokine suppression
- B. Formation of memory and effector cells
- C. Antigen elimination without cellular proliferation
- D. Destruction of the lymphocyte
Correct Answer: B
Rationale: The correct answer is B because clonal selection during lymphocyte activation leads to the formation of memory and effector cells. This process involves the proliferation and differentiation of the activated lymphocyte into these specialized cells, which play crucial roles in immune responses upon encountering the same antigen in the future. Cytokine suppression (choice A) is not the direct outcome of clonal selection but may be a regulatory mechanism during immune responses. Antigen elimination without cellular proliferation (choice C) is not accurate as clonal selection involves the expansion of specific lymphocyte clones. Destruction of the lymphocyte (choice D) is not the outcome of clonal selection, as activated lymphocytes undergo proliferation and differentiation rather than destruction.
A patient has come to the ambulatory care clinic with a sprain. The nurse correctly differentiates a grade 2 sprain from a grade 3 sprain with the assessment of which finding?
- A. Pain
- B. Swelling
- C. Bleeding into the joint
- D. Minor loss of function
Correct Answer: D
Rationale: The correct answer is D: Minor loss of function. A grade 2 sprain involves partial tearing of the ligament, leading to moderate pain, swelling, and a significant loss of function. In contrast, a grade 3 sprain involves complete tearing of the ligament, resulting in severe pain, significant swelling, and major loss of function. By assessing for minor loss of function, the nurse can differentiate between the two grades of sprains. Choices A, B, and C are incorrect because they do not specifically differentiate between a grade 2 and grade 3 sprain based on the level of functional impairment.