['Excess nitric oxide (NO) and its reactive derivatives cause oxidative reactions that lead to cell death. Propofol, an intravenous anesthetic, exhibits antioxidant properties. Diprivan is a widely used commercial preparation of propofol that is emulsified in 10% intralipids. We sought to test the hypothesis that clinically encountered concentrations of Diprivan attenuate the toxicity of NO in a cell culture model.', 'Prospective, randomized, controlled trial.', 'University research laboratory.', 'Cultured human bronchial epithelial (IB-3) cells.', 'Human bronchial epithelial cell cultures were randomly assigned to one of the following six groups: no additives (negative control), NO alone (positive control), NO with either 1 micro M, 10 micro M or 100 micro M Diprivan, and 100 micro M Diprivan alone (Diprivan control). S-nitroso-N-acetylpenicillamine (SNAP) was used to generate NO.', 'Hemacytometry with trypan blue staining was used to measure cell survival. To assess direct NO toxicity, immunoblot assays for nitrotyrosine-containing proteins in cell homogenates were performed. Exogenous NO significantly decreased live cell numbers and increased intracellular nitrotyrosine-containing protein concentrations (p<0.001). Diprivan significantly attenuated these changes in a concentration-independent manner (p<0.001). At concentrations as low as 1 micro M, Diprivan exhibited cytoprotective effects.'] Does diprivan attenuate the cytotoxicity of nitric oxide in cultured human bronchial epithelial cells?