title: Pupil diameters and the action of phenylephrine in twins.
mesh_terms: D000328:Adult; D000367:Age Factors; D005260:Female; D006801:Humans; D007498:Iris / Q000033:anatomy & histology; D008297:Male; D008875:Middle Aged; D010656:Phenylephrine / Q000494:pharmacology*; D011247:Pregnancy; D011680:Pupil / Q000033:anatomy & histology / Q000187:drug effects*; D012737:Sex Factors; D014427:Twins
chemical_list: D010656:Phenylephrine