Question 1

A 23-year-old woman has a severe viral respiratory infection. Her temperature is 38.9°C (102°F) , but decreases after she takes aspirin. Which of the following is the most likely mechanism of action of aspirin in decreasing the fever?

Accepted Answer

A)   activation of adenylate cyclase
B)   blockade of the action of exogenous viral pyrogens
C)   inactivation of lipoxygenase
D)   inhibition of cyclooxygenase
E)   prevention of mast cell degranulation DEXPLANATION: The antipyretic (fever reducing) effects of aspirin are due to the ability of this drug to block the synthesis of pro-inflammatory and pyretic prostaglandins from arachidonic acid. The synthesis of the prostaglandins is initiated via the activity of PGS. This enzyme possesses 2 activities, COX and peroxidase. One of the actions of aspirin (acetylsalicylic acid) is the inhibition of the COX activity of PGS.

Question 2

You are examining the effects of an experimental compound on the synthesis of series-2 prostaglandins. You find that addition of the compound to endothelial cells in culture results in the same level of inhibition as that observed for acetylsalicylate. These results indicate that the compound is inhibiting which of the following reactions of prostaglandin synthesis?

Accepted Answer

A)   acetyltransferase reaction
B)   desaturation reaction
C)   hydrolytic reaction
D)   hydroxylation reaction
E)   oxygenation reaction

Question 3

You are studying the effects of a novel compound in a variety of vascular and immune system assays. Your results demonstrate that the compound exhibits actitivies very similar to a previously identified eicosanoid. These activities include inhibition of platelet and leukocyte aggregation, induction of smooth muscle relaxation, decreased proliferation of T cells, decreased lymphocyte migration, and decreased secretion of IL-1a and IL-2. Which of the following eicosanoids exhibits biological activities most closely resembling those of your test compound?

Accepted Answer

A)   LTB4
B)   LTC4
C)   PGE2
D)   PGI2
E)   TXA2

Question 4

In a healthy newborn soon after delivery, there is constriction of the ductus arteriosus. This process is most likely influenced by which of the following changes?

Accepted Answer

A)   decreased serum calcium concentration
B)   decreased serum glucose concentration
C)   decreased serum prostaglandin concentration
D)   increased serum calcium concentration
E)   increased venous blood flow

Question 5

Cells isolated from the lungs of experimental mice via alveolar lavage are being studied for their responses to various lipid molecules.
Results indicate that addition of arachidonic acid leads to increased production of PGE2 but that LTA4 is not detected. Which of the following enzymes is most likely defective explaining the observed results?

Accepted Answer

A)   COX-1
B)   5-LOX
C)   LTC4 synthase
D)   prostacylin synthase
E)   thromboxane synthase

Question 6

You are investigating a novel series 1 prostaglandin inhibitor on the activity of a section of femoral artery in culture. You have shown that the inhibitory compound directly interferes with the action of PGE
1)  Which of the following activies is most likely reduced or absent in your organ culture system in the presence of this inhibitor?

Accepted Answer

A)   activation of 5-LOX for leukotriene synthesis
B)   enhancement of neutrophil adhesion
C)   induction of slow cardiac contraction
D)   platelet aggregation and activation
E)   relaxation of vascular smooth muscle cells EEXPLANATION: PGE1 is a series 1 eicosanoid derived from linoleic acid or g-linolenic acid (GLA). This lipid induces vasodilation through relaxation of smooth muscle cells, exhibits anti-inflammatory activity, and inhibits platelet aggregation.

Question 7

A 71-year old man was admitted to the hospital after getting very dizzy upon rising from the toilet seat. At that time, his pulse was racing and he remembers that his stool looked very different than usual. Over the last 4 or 5 weeks before the incident, the patient self-medicated with highdose ibuprofen TID to control some pain in his hips. What is the mechanism of action for nonsteroidal anti-inflammatory drugs (NSAIDs)  to cause gastrointestinal bleeding?

Accepted Answer

A)   they inhibit arachidonic acid synthesis
B)   they inhibit bradykinin synthesis
C)   they inhibit cyclooxygenase
D)   they inhibit histamine synthesis
E)   they promote prostaglandin synthesis

Question 8

You are carrying out clinical studies aimed at determining the optimal nutritional requirements for the production of the series-2 prostaglandins. Your studies determine that this production can be met by the daily ingestion of approximately 10 g of which of the following fatty acids?

Accepted Answer

A)   adipic
B)   linoleic
C)   palmitic
D)   stearic
E)   suberic BEXPLANATION: Prostaglandins are synthesized from the 20-carbon polyunsaturated fatty acid, arachidonic acid, which itself is synthesized from the essential fatty acid, linoleic acid. Linoleic acid is termed an essential fatty acid because it contains sites of unsaturation that human tissues cannot introduce and the lipid must, therefore, be acquired in the diet.

Question 9

You are examining the effects of an experimental compound on the activities of cultured sections of rat coronary artery. You determine that the compound exerts an effect identical to the natural prostaglandin, PGE2 indicating that the compound is exerting which of the folllowing activities?

Accepted Answer

A)   enhanced endothelial permeability
B)   increased neutrophil adhesion
C)   inhibited platelet adhesion
D)   smooth muscle contraction
E)   smooth muscle relaxation

Exam 22: Lipids: the Eicosanoids: Prostaglandins, Leukotrienes, and Thromboxanes

A 23-year-old woman has a severe viral respiratory infection. Her temperature is 38.9°C (102°F) , but decreases after she takes aspirin. Which of the following is the most likely mechanism of action of aspirin in decreasing the fever?

Correct Answer
verified

Correct Answer
verified

In a healthy newborn soon after delivery, there is constriction of the ductus arteriosus. This process is most likely influenced by which of the following changes?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
E
EXPLANATION: PGE₁ is a series 1 eicosanoid derived from linoleic acid or g-linolenic acid (GLA). This lipid induces vasodilation through relaxation of smooth muscle cells, exhibits anti-inflammatory activity, and inhibits platelet aggregation.

Correct Answer
verified

You are carrying out clinical studies aimed at determining the optimal nutritional requirements for the production of the series-2 prostaglandins. Your studies determine that this production can be met by the daily ingestion of approximately 10 g of which of the following fatty acids?

You are examining the effects of an experimental compound on the activities of cultured sections of rat coronary artery. You determine that the compound exerts an effect identical to the natural prostaglandin, PGE₂ indicating that the compound is exerting which of the folllowing activities?

Correct Answer
verified

Exam 22: Lipids: the Eicosanoids: Prostaglandins, Leukotrienes, and Thromboxanes

A 23-year-old woman has a severe viral respiratory infection. Her temperature is 38.9°C (102°F) , but decreases after she takes aspirin. Which of the following is the most likely mechanism of action of aspirin in decreasing the fever?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

In a healthy newborn soon after delivery, there is constriction of the ductus arteriosus. This process is most likely influenced by which of the following changes?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedEEXPLANATION: PGE1 is a series 1 eicosanoid derived from linoleic acid or g-linolenic acid (GLA). This lipid induces vasodilation through relaxation of smooth muscle cells, exhibits anti-inflammatory activity, and inhibits platelet aggregation.

Correct AnswerverifiedShow Answer

You are carrying out clinical studies aimed at determining the optimal nutritional requirements for the production of the series-2 prostaglandins. Your studies determine that this production can be met by the daily ingestion of approximately 10 g of which of the following fatty acids?

You are examining the effects of an experimental compound on the activities of cultured sections of rat coronary artery. You determine that the compound exerts an effect identical to the natural prostaglandin, PGE2 indicating that the compound is exerting which of the folllowing activities?

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
E
EXPLANATION: PGE₁ is a series 1 eicosanoid derived from linoleic acid or g-linolenic acid (GLA). This lipid induces vasodilation through relaxation of smooth muscle cells, exhibits anti-inflammatory activity, and inhibits platelet aggregation.

Correct Answer
verified

You are examining the effects of an experimental compound on the activities of cultured sections of rat coronary artery. You determine that the compound exerts an effect identical to the natural prostaglandin, PGE₂ indicating that the compound is exerting which of the folllowing activities?

Correct Answer
verified