arginine priority journal 76 article 72 nonhuman 68 controlled study 52 unclassified drug 44 Animals 38 human 34 Arginine 32 metabolism 28 Humans 26 serine 26 Trypanosoma cruzi 24 amino acid sequence 18 enzyme activity 18 nucleotide sequence 18 protein expression 18 genetics 16 nitric oxide 16 Nitric Oxide 14 Nitric oxide 14 animal cell 14 cysteine 14 gene expression 14 male 14 messenger RNA 14 physiology 14 Female 12 Male 12 Recombinant Proteins 12