Defining histopathologic cell for Hodgkin lymphoma?

Correct Answer: C

Rationale: The correct answer is C: Reed-Sternberg cell. These large, abnormal cells are characteristic of Hodgkin lymphoma. They originate from B cells but have lost most B cell markers. They express CD30 and CD15. A is incorrect as Hodgkin lymphoma is not derived from cytotoxic T cells. B is incorrect as it is not a malignancy involving NK cells. D is incorrect as Hodgkin lymphoma does not involve CD33+ clonal B cells.

Correct Answer: A

Rationale: Correct Answer: A - Low TIBC Rationale: - Pallor, fatigue, koilonychias, and cheilosis are symptoms of iron deficiency anemia. - Low TIBC is not an expected lab finding in iron deficiency anemia. - TIBC measures the total amount of iron that can be carried in the blood by transferrin. In iron deficiency anemia, TIBC is typically elevated, not low. - High serum transferrin, low iron:TIBC ratio, and low serum ferritin are all expected lab findings in iron deficiency anemia indicating low iron stores and increased iron-binding capacity.

Correct Answer: A

Rationale: The correct answer is A: Acute myeloid leukemia. The key clues are the presence of 15% myeloblasts and reduced erythropoiesis. In AML, there is an abnormal increase in myeloblasts in the bone marrow, leading to reduced production of normal blood cells, including erythrocytes. Myelofibrosis (C) is characterized by fibrotic changes in the bone marrow, not an increase in blasts. ALL (B) primarily affects lymphoid cells, not myeloblasts. MDS (D) involves ineffective hematopoiesis and dysplastic changes, but not necessarily a high blast count.

Correct Answer: D

Rationale: The correct answer is D: Schizonticidal activity. Artemisinin targets and kills the asexual blood stage of the malaria parasite Plasmodium falciparum, known as schizonts. This action helps in treating resistant falciparum malaria. Gametocidal activity (A) targets sexual stage parasites, preventing transmission but not directly treating the infection. Preventing hypnozoites (B) is specific to Plasmodium vivax and ovale, not falciparum. Sporontocidal activity (C) targets mosquito-stage parasites, which is not relevant for treating resistant falciparum malaria.

Correct Answer: B

Rationale: Step-by-step rationale: 1. IgM is the first immunoglobulin produced in primary immune response. 2. It is released by plasma cells when an antigen is encountered. 3. IgM is efficient in agglutination and complement activation. Summary of incorrect choices: A: IgA is mainly found in mucosal areas. C: IgE is involved in allergic reactions. D: IgG is the most abundant immunoglobulin in the bloodstream.