The clinical and diagnostic features of catecholamine secreting glomus tumors are reviewed. Three cases are reported, including the first documented case of a dopamine secreting glomus jugulare tumor. Based on this experience, the authors have outlined the indications for selective venous catheterterization studies and for pharmacologic blockage in the management of these patients. In addition to routine urinary screening, a high index of clinical suspicion is needed to avoid the complications associated with catecholamine secreting tumors.
Pulmonary surfactant replacement has previously been shown to be effective in the human neonatal respiratory distress syndrome. The value of surfactant replacement in models of acute lung injury other than quantitative surfactant deficiency states is, however, uncertain. In this study an acute lung injury model using rats with chronic indwelling arterial catheters, injured with N-nitroso-N-methylurethane (NNNMU), has been developed. The NNNMU injury was found to produce hypoxia, increased mortality, an alveolitis, and alterations in the pulmonary surfactant system. Alterations of surfactant obtained by bronchoalveolar lavage included a reduction in the phospholipid-to-protein ratio, reduced surface activity, and alterations in the relative percentages of the individual phospholipids compared with controls. Treatment of the NNNMU-injured rats with instilled exogenous surfactant (Survanta) improved oxygenation; reduced mortality to control values; and returned the surfactant phospholipid-to-protein ratio, surface activity, and, with the exception of phosphatidylglycerol, the relative percentages of individual surfactant phospholipids to control values.
Subcutaneous injection of N-nitroso-N-methylurethane (NNNMU) produces an acute lung injury mimicking the adult respiratory distress syndrome. NNNMU-injured rats treated with intratracheal Survanta, 100 mg phospholipid/kg body weight, air, or normal saline were observed for 24 h. Twenty-four hours after treatment survival among Survanta-treated rats was significantly greater than for air- and saline-treated rats (9/15 vs. 2/15 and 3/15, respectively). The alveolar-to-arterial O2 gradient was lower in Survanta-treated than in either air- or saline-treated rats during the 24-h period. Analysis of bronchoalveolar lavage fluid revealed a higher phospholipid: protein ratio (1.73 +/- 0.31 Survanta-treated, 0.20 +/- 0.05 air control, and 0.41 +/- 0.17 saline control) and a more normal phospholipid composition among treated than control rats. Minimum dynamic surface tension was significantly lower among treated rats (10.9 +/- 2.9 dyn/cm) than air and saline control rats (36.0 +/- 0.6 and 35.8 +/- 1.0 dyn/com, respectively). In vitro mixing of surfactant with pulmonary edema proteins significantly raised the minimum surface tension of surfactant from a group of Survanta-treated, NNNMU-injured rats (8.7 +/- 3.5 dyn/cm before and 32.0 +/- 0.5 dyn/cm after mixing). Intratracheal Survanta shows a beneficial effect on physiologic parameters and biochemical and functional characteristics of alveolar surfactant for 24 h in rats with NNNMU-induced acute lung injury.
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