Graft versus host disease is a complication of transfusion in patients of bone marrow transplantation. This can be best avoided by

Correct Answer: B

Rationale: The correct answer is B: Irradiating the blood components before transfusion. Graft versus host disease occurs when donor immune cells attack the recipient's tissues. Irradiating blood components helps to eliminate donor T cells, reducing the risk of this complication. Choice A (Transfusion of packed cells) does not address the issue of donor T cells. Choice C (Transfusing fresh whole blood) may actually increase the risk as it contains more viable donor immune cells. Choice D (Replacement by crystalloids) is not a suitable alternative for blood transfusion.

Correct Answer: D

Rationale: The correct answer is D: Rapid schizonticidal activity. Artemisinin and its derivatives target the asexual stage of the malaria parasite's life cycle, specifically the schizont stage. By quickly destroying the schizonts, they effectively kill the parasites in the blood, leading to a rapid reduction in parasite load and alleviating symptoms. The other choices are incorrect because A (Rapid gametocidal activity) targets sexual stage parasites, B (Ability to prevent further development of hypnozoites) refers to relapse prevention in Plasmodium vivax and Plasmodium ovale infections, and C (Rapid sporontocidal activity) targets the mosquito stage of the parasite's life cycle.

Correct Answer: B

Rationale: The correct answer is B: submandibular glands. Waldeyer's ring consists of the pharyngeal tonsil (adenoids), tubal tonsils, palatine tonsils (faucal tonsils), and lingual tonsils. The submandibular glands are salivary glands located outside of Waldeyer's ring. The other choices are incorrect because they are all part of Waldeyer's ring, which is a ring of lymphoid tissue located in the pharynx.

Correct Answer: C

Rationale: The correct answer is C: rheumatoid arthritis. In rheumatoid arthritis, there is chronic inflammation leading to elevated levels of ferritin (Fe) due to increased iron storage and a normal total iron-binding capacity (TIBC). This is because despite the increased iron stores, the body is unable to utilize it fully due to chronic inflammation. Incorrect choices: A: Thalassemia major would typically present with decreased TIBC due to increased iron absorption to compensate for the chronic anemia. B: Haemosiderosis would show elevated Fe but a decreased TIBC due to iron overload. D: Disseminated malignancy may show elevated Fe levels but typically with a decreased TIBC due to anemia of chronic disease.

Correct Answer: C

Rationale: The correct answer is C: clubbing. Plummer Vinson syndrome is characterized by the triad of dysphagia, iron deficiency anemia, and esophageal webs. Clubbing is not a typical feature of this syndrome. Angular stomatitis (A), splenomegaly (B), and post cricoid web (D) are all associated with Plummer Vinson syndrome. Angular stomatitis is due to iron deficiency anemia, splenomegaly can be present due to chronic anemia, and post cricoid web is a characteristic finding in the esophagus of patients with this syndrome.