The intra and extrapulmonary distributions of inspired nitrogen dioxide (NO 2) were studied by exposing rhesus monkeys to air mixtures containing concentrations slightly greater than ambient (0.56 to 1.71 mg per m 3, or 0.30 to 0.91 ppm) of NO 2 labeled with tracer quantities of NO 2 containing nitrogen 13 dioxide ( 13NO 2). The 13NO 2 (half time, 10 min) was synthesized by the oxygen 16 (p, α) 13N nuclear reaction in an isochronous cyclotron. The intrapulmonary location and concentration of the inspired 13NO 2 was detected continously by external monitoring of the annihilation radiation consequent to positron emissions from disintegrating 13N. The 13N concentration of arterial blood was also measured at intervals, and the blood values were correlated with those from the lung. Chemical measurements of NO 2 concentration in inspired and expired air were performed by the Saltzman method. Control studies were performed with xenon 125 ( 125Xe) (half time, 17 hours). The results demonstrated that 50 to 60 percent of the inspired pollutant was retained by the primate during quiet respiration; the gas was distributed throughout the lungs. Once absorbed, NO 2 or chemical intermediates remained within the lungs for prolonged periods after cessation of exposure, and dissemination of the pollutant or its derivaties to extrapulmonary sites occurred via the blood stream. Indirect evidence indicated the probable reaction of NO 2 with water in the nasopharynx and lungs to form nitric and nitrous acids. The reaction of these acids with pulmonary and extrapulmonary tissues probably accounts for the biologic toxicity of NO 2.
|Original language||English (US)|
|Number of pages||10|
|Journal||American Review of Respiratory Disease|
|State||Published - Nov 21 1977|
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine