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N‐Acetylcysteine Reduces Methemoglobin in an In‐vitro Model of Glucose‐6‐phosphate Dehydrogenase Deficiency
Author(s) -
Wright Robert O.,
Woolf Alan D.,
Shan Michael W.,
Magnani Barbarajean
Publication year - 1998
Publication title -
academic emergency medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.221
H-Index - 124
eISSN - 1553-2712
pISSN - 1069-6563
DOI - 10.1111/j.1553-2712.1998.tb02617.x
Subject(s) - methemoglobin , medicine , acetylcysteine , antidote , methylene blue , hemoglobin , saline , glucose 6 phosphate dehydrogenase , in vitro , hydroxylamine , zoology , andrology , dehydrogenase , biochemistry , enzyme , toxicity , chemistry , biology , antioxidant , photocatalysis , catalysis
Objective: To determine whether N‐acetylcysteine (NAC) reduces methemoglobin (MHB) in an in‐vitro model of glucose‐6‐phosphate dehydrogenase (G6PD) deficiency, given that methylene blue is an ineffective MHB antidote in G6PD deficiency. Methods: Five volunteers donated blood, which was divided equally into 2 test tubes, centrifuged, and washed with Tris‐Mopps buffer (pH 7.4, 15 mmol/L glucose). Both tubes were incubated with epiandrosterone (EA) (400 μmol), a specific inhibitor of G6PD. After 75 μL of 0.18 mol hydroxylamine (HA) was added to induce MHB formation, 150 μL of NAC (20 mg/mL) was added to tube 1 and 150 μL of phosphate‐buffered saline (PBS) was added to tube 2 as a volume control. Serial MHB levels are reported as a percentage of total hemoglobin (Hb). G6PD activity was measured at baseline, 15 minutes after EA, and at 5 hours. Results: Mean G6PD activity at baseline was 9.2 ± 2.9 U/g Hb (normal >4.6 U/g Hb); 15 minutes after EA was 3.0 ± 1.0 U/g Hb; and at experiment's end was 2.3 ± 0.7 U/g Hb. The mean (±SD) areas under the concentration‐time curves (AUCs) of NAC‐EA‐HA and PBS‐EA‐HA samples were compared using an unpaired t‐test and were significantly different: PBS‐EA‐HA, 20,400 ± 1,100 % min, vs NAC‐EA‐HA, 10,400 ± 1,000 % min, respectively (p < 0.05). Conclusion: In this in‐vitro model of G6PD deficiency, NAC efficiently reduced MHB.