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Clot formation is limited by the opposing effects of PGI2 and TXA2. Linear molecules known as LT, which are produced from arachidonic acid through the 5-lipoxygenase (5-LOX) pathway, play a role in mediating allergic responses. The synthesis of LT is inhibited by cortisol but not by aspirin. The substances involved in clot formation include glycosphingolipids, eicosanoids, and phospholipase A2 (PLA2). Nonsteroidal anti-inflammatory drugs (NSAID) are abbreviated as NSAID and sulfate ion as = sulfate ion.

Choose the ONE best answer.
7.1. Aspirin-exacerbated respiratory disease (AERD) is a severe reaction to nonsteroidal anti-inflammatory drugs (NSAID) that causes bronchoconstriction within 30 minutes to several hours after ingestion. What is the best explanation for the symptoms observed in patients with AERD? NSAID:
A. Thickens mucus, leading to airway blockage by inhibiting the activity of the cystic fibrosis transmembrane conductance regulator protein.
B. Diverts arachidonic acid to leukotriene synthesis by inhibiting cyclooxygenase but not lipoxygenase.
C. Increases the synthesis of vasodilatory prostaglandins by activating the cyclooxygenase activity of prostaglandin H2 synthase.
D. Causes alveolar collapse (atelectasis) by activating phospholipases, resulting in decreased levels of dipalmitoylphosphatidylcholine.

Correct answer = B. NSAID inhibit cyclooxygenase but not lipoxygenase, leading to the utilization of arachidonic acid for the production of bronchoconstricting leukotrienes. NSAID do not affect the cystic fibrosis (CF) transmembrane conductance regulator protein, which is responsible for CF when defective. Phospholipase A2 is inhibited by steroids, not NSAID. NSAID inhibit cyclooxygenase, rather than activating it. NSAID do not have an impact on phospholipases.

7.2. An infant born at 28 weeks' gestation rapidly developed respiratory distress. Diagnostic results from clinical laboratory and imaging studies supported the diagnosis of infant respiratory distress syndrome. Which statement regarding this syndrome is correct?
A. It is unrelated to the premature birth of the baby.
B. It occurs due to a deficiency of type II pneumocytes.
C. The lecithin/sphingomyelin ratio in the amniotic fluid is likely to be high (>2).
D. The concentration of dipalmitoylphosphatidylcholine in the amniotic fluid is expected to be lower than that in a full-term baby.
E. It is a easily treatable disorder with low mortality.
F. Administering surfactant to the mother shortly before birth is the treatment for this syndrome.

Correct answer = D. Dipalmitoylphosphatidylcholine (DPPC or dipalmitoyl lecithin) is the specific lung surfactant found in mature and healthy lungs. Insufficient production of this compound can lead to respiratory distress syndrome (RDS). A lecithin/sphingomyelin (L/S) ratio of ≥2 in the amniotic fluid indicates adequate lung maturation in a newborn (a ratio of <2 is expected in premature lungs). RDS is not caused by a deficiency of type II pneumocytes, which would result in the secretion of sphingomyelin instead of DPPC at 28 weeks' gestation. Prior to delivery, the mother is given a glucocorticoid, not surfactant. Surfactant administration to the newborn after birth helps reduce surface tension.

7.3. A 10-year-old boy presented with burning sensations in his feet and clusters of small, red-purple spots on his skin. Laboratory tests revealed proteinuria. Enzyme analysis showed a deficiency of α-galactosidase, and enzyme replacement therapy was recommended. What is the most likely diagnosis?

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Opposing effects of PGI2 and TXA2 limit clot formation. LT are linear molecules produced from arachidonic acid by the 5-lipoxygenase (5-LOX) pathway. They mediate allergic response. Their synthesis is inhibited by cortisol and not by aspirin.
glycosphingolipids, and eicosanoids. PLA2 = phospholipase A2; = sulfate ion; NSAID = nonsteroidal anti-inflammatory drugs.
Choose the ONE best answer.
7.1. Aspirin-exacerbated respiratory disease (AERD) is a severe reaction to nonsteroidal anti-inflammatory drugs (NSAID) characterized by bronchoconstriction 30 minutes to several hours after ingestion. Which of the following statements best explains the symptoms seen in patients with AERD? NSAID:
A. inhibit the activity of the cystic fibrosis transmembrane conductance regulator protein, resulting in thickened mucus that block airways.
B. inhibit cyclooxygenase but not lipoxygenase, resulting in the flow of arachidonic acid to leukotriene synthesis.
C. activate the cyclooxygenase activity of prostaglandin H2 synthase, resulting in increased synthesis of prostaglandins that promote vasodilation.
D. activate phospholipases, resulting in decreased amounts of dipalmitoylphosphatidylcholine and alveolar collapse (atelectasis).
Correct answer = B. NSAID inhibit cyclooxygenase but not lipoxygenase, so any arachidonic acid available is used for the synthesis of bronchoconstricting leukotrienes. NSAID have no effect on the cystic fibrosis (CF) transmembrane conductance regulator protein, defects in which are the cause of CF. Steroids, not NSAID, inhibit phospholipase A2. Cyclooxygenase is inhibited by NSAID, not activated. NSAID have no effect on phospholipases.
7.2. An infant, born at 28 weeks’ gestation, rapidly gave evidence of respiratory distress. Clinical laboratory and imaging results supported the diagnosis of infant respiratory distress syndrome. Which of the following statements about this syndrome is true?
A. It is unrelated to the baby’s premature birth.
B. It is a consequence of too few type II pneumocytes.
C. The lecithin/sphingomyelin ratio in the amniotic fluid is likely to be high (>2).
D. The concentration of dipalmitoylphosphatidylcholine in the amniotic fluid would be expected to be lower than that of a full-term baby.
E. It is an easily treated disorder with low mortality.
F. It is treated by administering surfactant to the mother just before she gives birth.
Correct answer = D. Dipalmitoylphosphatidylcholine (DPPC or, dipalmitoyl lecithin) is the lung surfactant found in mature, healthy lungs. Respiratory distress syndrome (RDS) can occur in lungs that make too little of this compound. If the lecithin/sphingomyelin (L/S) ratio in amniotic fluid is ≥2, a newborn’s lungs are considered to be sufficiently mature (premature lungs would be expected to have a ratio <2). The RDS would not be due to too few type II pneumocytes, which would simply be secreting sphingomyelin rather than DPPC at 28 weeks’ gestation. The mother is given a glucocorticoid, not surfactant, prior to giving birth (antenatally). Surfactant would be administered to the baby postnatally to reduce surface tension.
7.3. A 10-year-old boy was evaluated for burning sensations in his feet and clusters of small, red-purple spots on his skin. Laboratory studies revealed protein in his urine. Enzymatic analysis revealed a deficiency of αgalactosidase, and enzyme replacement therapy was recommended. The most likely diagnosis is: