Hemoglobin and Nitric Oxide

To the Editor: The article by Schechter and Gladwin (April 10 issue) 1 is flawed by a fundamental error. The conclusions that the authors draw from reports of measured S-nitrosohemoglobin levels and decomposition rates are not disciplined by quantitative standards of efficacy: “lower” does not imply “too low,” nor does “rapid” imply “too rapid.” The authors cite studies in which S-nitrosohemoglobin levels (approximately 50 nmol per liter) are lower than those in previous reports (micromolar levels). They fail to mention, however, that Pawloski et al. demonstrated bioactivity of red cells with S-nitrosohemoglobin at 50 nmol per liter, 2 and McMahon et al. . . .