title: Studies on the haemopoietic toxicity of nitrous oxide in man.
abstract: Nitrous oxide inactivates vitamin B12 and in man can produce a megaloblastic anaemia. Haematological and biochemical changes were studied in nine surgical patients ventilated with 70% N2O for up to 24 h and in three control patients. There was a rise in the numbers of hypersegmented neutrophils in peripheral blood following N2O. Serial bone marrow aspirates showed gross megaloblastic change after 24 h of N2O which had reverted to normoblastic but dyserythropoietic haemopoiesis by 1 week. Giant forms of early myeloid precursors were also seen after 24 h ventilation with N2O but by 1 week abnormalities were evident in more mature cells, metamyelocytes and segmented neutrophils. Megaloblastosis was associated with abnormal dU suppression which showed a correction pattern similar to that seen in vitamin B12 deficiency. Administration of N2O was also associated with a progressive rise in serum folate and fall in serum methionine levels. No similar patterns were seen in the three control patients.
mesh_terms: D000768:Anesthesia, General; D001853:Bone Marrow / Q000378:metabolism; D003857:Deoxyuridine / Q000378:metabolism; D005492:Folic Acid / Q000097:blood; D006410:Hematopoiesis / Q000187:drug effects*; D006801:Humans; D008534:Megaloblasts / Q000187:drug effects; D008715:Methionine / Q000097:blood; D009504:Neutrophils / Q000187:drug effects*; D009609:Nitrous Oxide / Q000009:adverse effects*; D010976:Platelet Count / Q000187:drug effects; D013997:Time Factors; D014805:Vitamin B 12 / Q000097:blood
chemical_list: D005492:Folic Acid; D008715:Methionine; D009609:Nitrous Oxide; D014805:Vitamin B 12; D003857:Deoxyuridine