Nokea
Which of the following is a key feature of Factor XIII?
- A. Its half-life is about 10 days.
- B. It is an important activator of thrombin.
- C. Its levels are normal in newborns.
- D. It is part of the contact activation system.
Correct Answer: A
Rationale: The correct answer is A: Its half-life is about 10 days. Factor XIII has a long half-life due to its stable tetrameric structure, allowing it to circulate in the blood for about 10-14 days. This extended half-life is crucial for its role in stabilizing fibrin clots.
Explanation for why other choices are incorrect:
B: Factor XIII is not an activator of thrombin; rather, it crosslinks fibrin strands to strengthen clots.
C: Factor XIII levels are low in newborns and gradually increase during the first few months of life.
D: Factor XIII is not part of the contact activation system, which involves factors XII, XI, and prekallikrein.
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A 16-year-old female presents to the emergency room with a new complaint of chest pain. When performing a review of systems and physical examination, which of the following would substantially decrease your suspicion for a diagnosis of pulmonary embolism?
- A. Cough
- B. Fever
- C. Rib tenderness
- D. Shortness of breath
Correct Answer: C
Rationale: The correct answer is C: Rib tenderness. Rib tenderness would decrease suspicion for pulmonary embolism because it suggests a musculoskeletal origin of chest pain rather than a vascular one. Pulmonary embolism typically presents with symptoms such as shortness of breath, pleuritic chest pain, and sometimes cough, but rib tenderness is not a common finding in this condition. Fever is non-specific and can be present in various conditions, including pulmonary embolism. Shortness of breath is a key symptom of pulmonary embolism and would increase suspicion for this diagnosis.
A client is having a radioisotopic imaging scan. What action by the nurse is most important?
- A. Assess the client for shellfish allergies.
- B. Place the client on radiation precautions.
- C. Sedate the client before the scan.
- D. Teach the client about the procedure.
Correct Answer: D
Rationale: The correct answer is D because educating the client about the procedure is crucial for informed consent, reducing anxiety, and promoting cooperation during the scan. This empowers the client to understand what to expect and how to prepare. Assessing for shellfish allergies (A) is not directly related to the scan. Placing the client on radiation precautions (B) is unnecessary as the exposure is minimal, and sedating the client (C) should only be considered if medically indicated, not as a routine practice.
RBCs break into fragments, they are referred to as schistocytes. These type of cells are seen in
- A. Sickle cell trait
- B. Thalassemia
- C. Microangiopathic hemolytic anemia
- D. Idiopathic thrombocytopenic purpura
Correct Answer: C
Rationale: The correct answer is C: Microangiopathic hemolytic anemia. Schistocytes are fragmented red blood cells seen in conditions where RBCs are physically sheared or damaged as they pass through small blood vessels. In microangiopathic hemolytic anemia, abnormal or damaged blood vessels cause mechanical destruction of RBCs, leading to the formation of schistocytes. Sickle cell trait (A) and Thalassemia (B) are genetic disorders that do not typically cause schistocytes. Idiopathic thrombocytopenic purpura (D) is a condition characterized by low platelet count, not associated with schistocytes.
Several gene mutations have been associated with juvenile myelomonocytic leukemia (JMML), and they may or may not have prognostic implications. A gene expression–based classification system has been found to be an independent predictor of clinical outcome in these patients. What is the disease signature that predicts a poor outcome?
- A. Tyrosine kinase inhibitors
- B. Acute myeloid leukemia–like
- C. Chronic myeloid leukemia-like
- D. BRAF pathway abnormalities
Correct Answer: B
Rationale: The correct answer is B: Acute myeloid leukemia-like. This is because JMML shares similarities with acute myeloid leukemia in terms of aggressive progression and poor outcomes. Children with JMML who exhibit an acute myeloid leukemia-like gene expression signature have been shown to have a worse prognosis compared to those with other gene expression profiles. The other choices (A, C, D) are incorrect because tyrosine kinase inhibitors are not directly related to predicting clinical outcomes in JMML, chronic myeloid leukemia-like gene expression profile does not necessarily predict poor outcomes in JMML, and BRAF pathway abnormalities are not specifically associated with predicting poor outcomes in JMML.
A 9-year-old boy presents to the emergency department with emesis and headache of 3 weeks' duration. MRI reveals a large heterogeneous mass in the cerebellum. He undergoes a resection, and the pathology is most consistent with a classic medulloblastoma. Which of the following findings would classify the patient as a high-risk medulloblastoma?
- A. Elevated serum and CSF AFP and beta-HCG tumor markers
- B. WNT subgrouping on molecular classification
- C. A presurgical spine MRI that reveals bulky tumor in the spine
- D. A postoperative brain MRI with no signs of residual tumor
Correct Answer: C
Rationale: The correct answer is C. A presurgical spine MRI revealing bulky tumor in the spine classifies the patient as high-risk due to leptomeningeal spread. This indicates dissemination of the tumor cells beyond the primary site, leading to a poorer prognosis. Choice A is incorrect as AFP and beta-HCG markers are associated with germ cell tumors, not medulloblastomas. Choice B is incorrect as WNT subgrouping is associated with better outcomes. Choice D is incorrect because the absence of residual tumor postoperatively does not necessarily indicate high-risk disease.