A 49-year-old man is brought to the emergency department after being discovered unconscious in a field near the county fair. Several empty bottles of vodka were found near him. On arrival, he is mumbling incoherently. He appears malodorous and disheveled. Serum studies show: Na+ 150 mEq/L K+ 3.3 mEq/L Cl- 115 mEq/L HCO3- 13 mEq/L Urea nitrogen 30 mg/dL Glucose 75 mg/dL Creatinine 1.4 mg/dL Lactic acid 6 mmol/L (N < 2) Which of the following changes to enzyme activity best explains this patient's laboratory findings?
AIncreased activity of phenylalanine hydroxylase
BDecreased activity of glucose-6-phosphate dehydrogenase
CDecreased activity of phosphofructokinase-2
DDecreased activity of pyruvate dehydrogenase
EIncreased activity of α-ketoglutarate dehydrogenase
An investigator is studying nutritional deficiencies in humans. A group of healthy volunteers are started on a diet deficient in pantothenic acid. After 4 weeks, several of the volunteers develop irritability, abdominal cramps, and burning paresthesias of their feet. These symptoms are fully reversed after reintroduction of pantothenic acid to their diet. The function of which of the following enzymes was most likely impaired in the volunteers during the study?
AGamma-glutamyl carboxylase
BAlpha-ketoglutarate dehydrogenase
CDopamine beta-hydroxylase
DMethionine synthase
EGlutathione reductase
A 4-month-old boy is brought to the physician because of a seizure. He was delivered at term after an uncomplicated pregnancy. He is currently at the 10th percentile for height, 5th percentile for weight, and 15th percentile for head circumference. Examination shows muscle hypotonia. His serum lactic acid and alanine are elevated. A functional assay of pyruvate dehydrogenase complex in serum leukocytes shows decreased enzyme activity. Supplementation with which of the following substances should be avoided in this patient?
AArachidonic acid
BRiboflavin
CThiamine
DLysine
EValine
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