891
Five cases (four from the literature and one new case) are presented in which patients unsuspected of having vitamin B12 deficiency developed subacute combined degeneration of the spinal cord following nitrous oxide anesthesia.
 Five cases (four from the literature and one new case) are presented in which patients unsuspected of having vitamin B12 deficiency: Subject; Five: Subject.Population; subacute combined degeneration of the spinal cord: Effect; nitrous oxide anesthesia: Treatment; nitrous oxide: Treatment.Drug; vitamin B12 deficiency: Treatment.Disorder
Given event type and trigger, please tell me the arguments of all the listed option. Output format is "name1: role1; name2: role2". 
Event type: adverse event 
  Option: Treatment.Freq, Subject.Population, Combination.Drug, Subject.Gender, Treatment.Duration, Subject, Effect, Treatment, Treatment.Disorder, Subject.Disorder, Treatment.Route, Subject.Race, Treatment.Time_elapsed, Treatment.Dosage, Subject.Age, Treatment.Drug 
Text: {0} 
Answer:
 Five cases (four from the literature and one new case) are presented in which patients unsuspected of having vitamin B12 deficiency: Subject; Five: Subject.Population; subacute combined degeneration of the spinal cord: Effect; nitrous oxide anesthesia: Treatment; nitrous oxide: Treatment.Drug; vitamin B12 deficiency: Treatment.Disorder