Since little is known about the contribution of endothelial nitric oxide sy
nthase (e-NOS) to the mechanism of pulmonary vasospasm and the development
of pulmonary vascular occlusive disease, we elucidate how e-NOS is expresse
d in lung biopsy specimens obtained from operative patients with pulmonary
hypertension. Lung biopsy specimens were obtained from 17 patients who unde
rwent open-heart operations for various heart diseases. A piece of normal l
ung specimen was also obtained from the resected lungs of three lung cancer
patients as a control. e-NOS expression was visualized with a monoclonal a
ntibody against e-NOS, and the level of expression was partially quantified
. Significantly high levels of e-NOS expression were seen in adult patients
. whose preoperative mean pulmonary arterial pressures were greater than 20
mm HE. In contrast, e-NOS expression in pediatric patients with the same l
evels of mean pulmonary arterial pressure was the same as that in the contr
ols and in low pulmonary arterial pressure. There was a statistically signi
ficant positive correlation between the level of eNOS expression and Heath-
Edwards grading. These data suggest that the e-NOS expression in lung tissu
e is induced when pulmonary vascular obstructive diseases progress. (C) 200
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