controlled study nonhuman Article 119 human 80 male 80 animal experiment 75 Animals 61 article 58 female 55 animal 54 Humans 53 animal model 48 animal tissue 44 adult 43 mouse 41 unclassified drug 37 rat 34 animal cell 32 Male 31 metabolism 31 Female 28 drug effect 27 genetics 23 Rats 22 chemistry 20 Mice 19 in vitro study 18 protein expression 18 gene expression 17 in vivo study 17