title: Pulmonary hypertension and the search for the selective pulmonary vasodilator.
mesh_terms: D000284:Administration, Oral; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000188:drug therapy*; D008297:Male; D009569:Nitric Oxide / Q000502:physiology* / Q000627:therapeutic use; D010879:Piperazines / Q000627:therapeutic use*; D011687:Purines; D000068677:Sildenafil Citrate; D013450:Sulfones; D014665:Vasodilator Agents / Q000627:therapeutic use*
chemical_list: D010879:Piperazines; D011687:Purines; D013450:Sulfones; D014665:Vasodilator Agents; D009569:Nitric Oxide; D000068677:Sildenafil Citrate