Nitric oxide and aids dementia

To the Editor: Lipton and Gendelman ascribe a key role to macrophages and reactive oxygen intermediates in the pathogenesis of dementia associated with human immunodeficiency virus (HIV) infection (April 6 issue).¹Since inhibi-tors of nitric oxide synthase were found to prevent gp120-induced neurotoxic effects in vitro, the authors speculate that nitric oxide triggers neurologic damage. However, it is questionable whether macrophages from humans, unlike those from other species, can produce relevant amounts of nitric oxide. Other cells in the brain, such as astrocytes, could be a source of nitric oxide, but there is no evidence of enhanced formation of nitric. . .