TOPICS: Protein catabolism, liver, urea, urea cycle, urine, alanine cycle, muscle, amino acids, nitrogen waste, neurotoxicity, carbamoyl phosphate synthetase I, ornithine transcarbamylase deficiency, ornithine transcarbamylase deficiency, hyperammonemia, orotic acid, pyrimidine pathway, pyridoxine (B6), liver disease, urea cycle disorders, neurological symptoms, encephalopathy, glutamine, astrocytes, glutamate, lactulose, rifaximin