A 43-Year-Old Man Is Being Evaluated for Occasional Retrosternal Chest

question 169

Multiple Choice

A 43-year-old man is being evaluated for occasional retrosternal chest pressure that develops with moderate exertion and sometimes occurs when resting.  He does not use alcohol, tobacco, or illicit drugs.  The patient has an extensive family history of coronary artery disease.  His temperature is 36.7 C (98 F) , blood pressure is 124/72 mm Hg, pulse is 81/min, and respirations are 14/min.  Physical examination shows no abnormalities.  Coronary angiography shows mild luminal irregularities but no significant obstructive lesions.  Acetylcholine infusion during the procedure results in dilation of epicardial coronary vessels.  A reaction involving which of the following amino acids is most likely responsible for the observed dilation?

• A)Arginine
• B)Aspartate
• C)Glutamate
• D)Tryptophan
• E)Tyrosine

---

Definitions:

Midpoint Method

A technique used in economics to calculate the elasticity of demand or supply by using the midpoint between two points on a curve instead of relying on the initial or final point alone.

Price Elasticity

An indicator of the degree to which the demand for a product reacts to shifts in its price, showing how susceptible demand is to price fluctuations.

Equation

A mathematical statement that asserts the equality of two expressions, usually written with an equals sign ("=").

Midpoint Method

A technique used in economics to calculate the elasticity of demand or supply by taking the average of the starting and ending prices and quantities.