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{{WBRQuestion
{{WBRQuestion
|QuestionAuthor={{Rim}}
|QuestionAuthor= {{YD}} (Reviewed by  {{YD}})
|ExamType=USMLE Step 1
|ExamType=USMLE Step 1
|MainCategory=Physiology
|MainCategory=Physiology
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|MainCategory=Physiology
|MainCategory=Physiology
|SubCategory=Cardiology
|SubCategory=Cardiology
|MainCategory=Physiology
|MainCategory=Physiology
|MainCategory=Physiology
|MainCategory=Physiology
|MainCategory=Physiology
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|MainCategory=Physiology
|MainCategory=Physiology
|SubCategory=Cardiology
|SubCategory=Cardiology
|Prompt=A researcher is studying the role of a new medication for the prophylaxis against myocardial infarction. He explains that the medication acts on the arachidonic acid pathway and counteracts atherosclerosis by increasing compounds that inhibit platelet aggregation that is known to play a major role in the pathogenesis of coronary artery disease. According to the diagram below, the new medication most likely promotes which part of the  pathway to achieve its therapeutic effect?
|Prompt=A researcher is studying the role of a new drug for the prophylaxis against myocardial infarction. He explains that the medication acts on the arachidonic acid pathway and counteracts atherosclerosis by increasing compounds that inhibit platelet aggregation, a process proven to play a major role in the pathogenesis of coronary artery disease. According to the diagram below, the new drug most likely promotes which part of the  pathway to achieve its therapeutic effect?


[[Image:WBR_Arachidonic_Acid_Pathway_Adapted.png|600px]]
[[Image:WBR_Arachidonic_Acid_Pathway_Adapted.png|600px]]
|Explanation=The medication described must have properties that lower platelet aggregation to counteract the process of myocardial infarction that promotes platelet aggregation. Prostacyclin (PGI2) is a potent inhibitor of platelet aggregation; it also promotes vasodilation, bronchodilation, and decreases uterine tone.  
|Explanation=The medication described must have properties that reduce platelet aggregation to counteract the process of myocardial infarction. Prostacyclin (PGI2) is a potent inhibitor of platelet aggregation. Also, it plays a role in promoting vasodilation and bronchodilation, along with decreasing uterine tone. Since the drug increases compounds that inhibit platelet aggregation, the new compound must increase PGI2 levels, and thus promote inhibition of platelet aggregation.
 
Since the medication increases compounds that inhibit platelet aggregation, the new compound must thus increase PGI2 and thus promote inhibition of platelet aggregation.


Educational Objective: Prostacyclin inhibits platelet aggregation.
|AnswerA=A
|AnswerA=A
|AnswerAExp=LTB4 is a neutrophil chemotactic agent. It does not play a major role in preventing platelet aggregation.
|AnswerAExp=LTB4 is a neutrophil chemotactic agent. It does not play a major role in reducing platelet aggregation.
|AnswerB=B
|AnswerB=B
|AnswerBExp=LTC4 and LTD4 are pro-inflammatory agents that play a role in bronchoconstriction.
|AnswerBExp=LTC4 and LTD4 are pro-inflammatory agents that play a role in bronchoconstriction.
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|AnswerCExp=Prostacyclin is a major inhibitor of platelet aggregation.
|AnswerCExp=Prostacyclin is a major inhibitor of platelet aggregation.
|AnswerD=D
|AnswerD=D
|AnswerDExp=Prostaglandins increase uterine tone, which may be utilized in pregnancy to induce labor. Prostaglandins also lower vascular and bronchial tone.
|AnswerDExp=Prostaglandins increase uterine tone. Prostaglandins may be administered to pregnant patients to induce labor. Prostaglandins also decrease vascular and bronchial tone.
|AnswerE=E
|AnswerE=E
|AnswerEExp=Thromboxane A2 has an opposing effect to prostacyclin. It increases platelet aggregation and plays a role in worsening atherosclerosis.
|AnswerEExp=Thromboxane A2 has an effect that opposes that of prostacyclin. It increases platelet aggregation and plays a role in worsening atherosclerosis.
|EducationalObjectives=Prostacyclin inhibits platelet aggregation.
|References=First Aid 2014 page 439
|RightAnswer=C
|RightAnswer=C
|WBRKeyword=arachidonic, acid, pathway, lipoxygenase, cycloxygenase, platelet, aggregation, prostacyclin, PGI2, thromboxane, inhibitor, inhibition, therapeutic, effect, effects, increase, decrease, atherosclerosis, myocardial, infarction, MI
|WBRKeyword=Arachidonic, Acid, Pathway, Arachidonic acid pathway, Lipoxygenase, Cyclooxygenase, Platelet, Aggregation, Prostacyclin, PGI2, Thromboxane, Inhibitor, Inhibition, Therapeutic, Platelet aggregation, Therapeutic effect, Atherosclerosis, Myocardial, Infarction, MI
|Approved=No
|Approved=Yes
}}
}}

Latest revision as of 01:32, 28 October 2020

 
Author [[PageAuthor::Yazan Daaboul, M.D. (Reviewed by Yazan Daaboul, M.D.)]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Physiology
Sub Category SubCategory::Cardiology
Prompt [[Prompt::A researcher is studying the role of a new drug for the prophylaxis against myocardial infarction. He explains that the medication acts on the arachidonic acid pathway and counteracts atherosclerosis by increasing compounds that inhibit platelet aggregation, a process proven to play a major role in the pathogenesis of coronary artery disease. According to the diagram below, the new drug most likely promotes which part of the pathway to achieve its therapeutic effect?

]]

Answer A AnswerA::A
Answer A Explanation AnswerAExp::LTB4 is a neutrophil chemotactic agent. It does not play a major role in reducing platelet aggregation.
Answer B AnswerB::B
Answer B Explanation AnswerBExp::LTC4 and LTD4 are pro-inflammatory agents that play a role in bronchoconstriction.
Answer C AnswerC::C
Answer C Explanation AnswerCExp::Prostacyclin is a major inhibitor of platelet aggregation.
Answer D AnswerD::D
Answer D Explanation AnswerDExp::Prostaglandins increase uterine tone. Prostaglandins may be administered to pregnant patients to induce labor. Prostaglandins also decrease vascular and bronchial tone.
Answer E AnswerE::E
Answer E Explanation AnswerEExp::Thromboxane A2 has an effect that opposes that of prostacyclin. It increases platelet aggregation and plays a role in worsening atherosclerosis.
Right Answer RightAnswer::C
Explanation [[Explanation::The medication described must have properties that reduce platelet aggregation to counteract the process of myocardial infarction. Prostacyclin (PGI2) is a potent inhibitor of platelet aggregation. Also, it plays a role in promoting vasodilation and bronchodilation, along with decreasing uterine tone. Since the drug increases compounds that inhibit platelet aggregation, the new compound must increase PGI2 levels, and thus promote inhibition of platelet aggregation.

Educational Objective: Prostacyclin inhibits platelet aggregation.
References: First Aid 2014 page 439]]

Approved Approved::Yes
Keyword WBRKeyword::Arachidonic, WBRKeyword::Acid, WBRKeyword::Pathway, WBRKeyword::Arachidonic acid pathway, WBRKeyword::Lipoxygenase, WBRKeyword::Cyclooxygenase, WBRKeyword::Platelet, WBRKeyword::Aggregation, WBRKeyword::Prostacyclin, WBRKeyword::PGI2, WBRKeyword::Thromboxane, WBRKeyword::Inhibitor, WBRKeyword::Inhibition, WBRKeyword::Therapeutic, WBRKeyword::Platelet aggregation, WBRKeyword::Therapeutic effect, WBRKeyword::Atherosclerosis, WBRKeyword::Myocardial, WBRKeyword::Infarction, WBRKeyword::MI
Linked Question Linked::
Order in Linked Questions LinkedOrder::