title: Letter: Lecithin/sphingomyelin ratios in oropharyngeal fluid.
mesh_terms: D001826:Body Fluids / Q000032:analysis*; D006801:Humans; D007231:Infant, Newborn; D009055:Mouth / Q000378:metabolism; D010614:Pharynx / Q000378:metabolism; D010713:Phosphatidylcholines / Q000032:analysis*; D012127:Respiratory Distress Syndrome, Newborn / Q000175:diagnosis*; D013109:Sphingomyelins / Q000032:analysis
chemical_list: D010713:Phosphatidylcholines; D013109:Sphingomyelins