Nokea
Which mutated tumor suppressor gene is most likely to contribute to many types of cancer, including bladder, breast, colorectal, and lung?
- A. p53
- B. APC
- C. BRCA1
- D. BRCA2
Correct Answer: A
Rationale: The p53 gene is a critical tumor suppressor gene involved in preventing cancer by regulating the cell cycle and initiating apoptosis. Mutations in this gene are associated with many types of cancer.
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A clinical indicator of inflammation is:
- A. Decreased concentration of C3b
- B. Increased concentration of C-reactive protein
- C. Decreased concentration of MBL
- D. All of the above
Correct Answer: B
Rationale: The correct answer is B: Increased concentration of C-reactive protein. This is because C-reactive protein is a well-established clinical indicator of inflammation, produced by the liver in response to inflammation. Choice A is incorrect because a decreased concentration of C3b is not a typical indicator of inflammation. Choice C is incorrect because mannose-binding lectin (MBL) is an acute-phase reactant that increases in response to inflammation, so a decreased concentration of MBL would not be indicative of inflammation. Choice D is incorrect as it includes all options, but only B is a valid clinical indicator of inflammation.
Patients with septic shock are treated, among other drugs, with activated protein C. The purpose of this treatment is to
- A. Dampen the cytokine storm
- B. Raise the blood pressure
- C. Resolve DIC (disseminated intravascular coagulation)
- D. Boost the immune response
Correct Answer: C
Rationale: The correct answer is C: Resolve DIC. Activated protein C is used in septic shock to address the coagulopathy associated with DIC, a common complication. Activated protein C inhibits clotting factors and promotes fibrinolysis, helping to restore normal coagulation function. This treatment does not directly dampen the cytokine storm (choice A), raise blood pressure (choice B), or boost the immune response (choice D) in septic shock patients. It specifically targets the coagulation abnormalities seen in DIC, making choice C the most appropriate answer.
Where do B cells mature?
- A. Bone marrow
- B. Thymus
- C. Spleen
- D. Lymph nodes
Correct Answer: A
Rationale: The correct answer is A: Bone marrow. B cells mature in the bone marrow where they develop from hematopoietic stem cells. This process involves gene rearrangement and selection for self-tolerance. The bone marrow provides a microenvironment necessary for B cell development. Choices B, C, and D are incorrect because the thymus is where T cells mature, the spleen is involved in immune responses but not B cell maturation, and lymph nodes are sites for immune cell activation and proliferation but not B cell maturation.
The release of IL-8 at an infection site specifically induces
- A. Increase of adhesion molecules on local endothelial cells
- B. Local recruitment of neutrophils
- C. Systemic effects, including fever
- D. Increase of acute-phase proteins
Correct Answer: B
Rationale: The correct answer is B because IL-8 is a chemokine that specifically functions to recruit neutrophils to the site of infection. Neutrophils are crucial for fighting off pathogens. A: Increase of adhesion molecules on local endothelial cells is not directly induced by IL-8. C: Systemic effects, including fever, are typically mediated by other cytokines like IL-1 and IL-6. D: Increase of acute-phase proteins is not the primary role of IL-8 in the immune response.
The major histocompatibility complex was given its name because the genes in this complex influence:
- A. T cell receptor gene rearrangement
- B. Acceptance or rejection of transplanted organs and cells
- C. Polarization of T helper cells
- D. The ratio of CD4+ and CD8+ T cells in an individual
Correct Answer: B
Rationale: The correct answer is B because the major histocompatibility complex (MHC) plays a crucial role in the immune system by determining whether transplanted organs or cells will be accepted or rejected. MHC molecules present antigens to T cells, which then trigger an immune response leading to acceptance or rejection. Choice A is incorrect because T cell receptor gene rearrangement is not directly influenced by the MHC. Choice C is incorrect as MHC does not directly polarize T helper cells. Choice D is incorrect because MHC does not directly regulate the ratio of CD4+ and CD8+ T cells in an individual.