Which drug can increase intracellular levels of cAMP by inhibiting cyclic nucleotide phosphodiesterase? 1. Sildenafil 2. Ticlopidine 3. Clopidogrel 4. Dipyridamole

Correct Answer: C

Rationale: The correct answer is C: 1,4. Sildenafil inhibits phosphodiesterase type 5, leading to increased cAMP levels. Dipyridamole also inhibits phosphodiesterase, increasing cAMP. Ticlopidine and clopidogrel do not affect cAMP levels. Therefore, choices A, B, and D are incorrect because they include drugs that do not inhibit phosphodiesterase to increase cAMP.

Correct Answer: D

Rationale: The correct answer is D: Eosinophils. Eosinophils are involved in allergic reactions due to their role in fighting parasitic infections and regulating inflammatory responses. During an allergic reaction, eosinophils increase in number to help combat the allergen. Lymphocytes (A) are involved in immune responses but are not specifically associated with allergic reactions. Neutrophils (B) are the most abundant type of white blood cells and are typically involved in bacterial infections, not allergic reactions. Monocytes (C) are involved in the immune response against pathogens but are not specifically related to allergic reactions. Eosinophils are the key players in allergic responses due to their specialized functions in combating allergens and modulating inflammation.

Correct Answer: B

Rationale: The correct answer is B: Lymphocyte. Lymphocytes can develop in sites other than the bone marrow, such as the thymus and lymph nodes. Monocytes, Megakaryocytes, and Neutrophils develop exclusively in the bone marrow. Monocytes differentiate into macrophages and dendritic cells, while Megakaryocytes produce platelets. Neutrophils are a type of white blood cell involved in the immune response. Therefore, only lymphocytes have the ability to develop outside the bone marrow, making choice B the correct answer.

Correct Answer: B

Rationale: The correct answer is B: Proper handwashing. This is the most important practice in preventing the spread of disease because it effectively removes germs and bacteria from hands, reducing the risk of transmission. Handwashing is crucial in healthcare settings to prevent infections. A: Wearing masks during patient contact is important, but handwashing is more effective in preventing disease spread as it directly addresses the transmission of germs through hands. C: Wearing disposable lab coats is important for infection control but not as crucial as proper handwashing, which directly removes germs from hands. D: Identifying specimens with red labels is important for handling potentially infectious materials, but handwashing is still the most essential practice in preventing disease spread as it addresses the primary mode of transmission through hands.

Correct Answer: A

Rationale: The correct answer is A (t(11;14)) as this translocation is specifically associated with multiple myeloma, involving the cyclin D1 gene on chromosome 11. This translocation leads to overexpression of cyclin D1, promoting cell cycle progression and contributing to the pathogenesis of multiple myeloma. Choice B (t(9;22)) is associated with chronic myeloid leukemia, not multiple myeloma. Choice C (t(15;17)) is related to acute promyelocytic leukemia. Choice D (t(8;14)) is seen in Burkitt lymphoma, not multiple myeloma. Thus, the correct answer is A due to its direct association with multiple myeloma.