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- Sun, B, et al.
(författare)
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Biophysical and physiological properties of a modified porcine surfactant enriched with surfactant protein A
- 1997
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Ingår i: The European respiratory journal. - : European Respiratory Society (ERS). - 0903-1936 .- 1399-3003. ; 10:9, s. 1967-1974
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Tidskriftsartikel (refereegranskat)abstract
- Surfactant protein A (SP-A), a major protein component of natural pulmonary surfactant, is absent in exogenous surfactants currently used in clinical practice. We investigated the physical and physiological properties of one of these modified natural surfactants (Curosurf) after enrichment with 5% SP-A (SP-A-Curosurf). A pulsating bubble system was used for in vitro assessments and ventilated newborn rabbits for evaluation of in vivo effects. In the presence of various potential inhibitors (meconium 5 mg.mL-1, fibrinogen 5 mg.mL-1, albumin 25 mg.mL-1, or whole serum proteins 25 mg.mL-1), Curosurf at a concentration of 5 mg.mL-1 was inactivated while SP-A-Curosurf and natural porcine surfactant at the same concentration had normal maximum and minimum surface tension. This protective effect of SP-A was calcium dependent. In immature newborn rabbits, the improvement of lung-thorax compliance observed after treatment with 100 mg.kg-1 of SP-A-Curosurf was equivalent to that obtained with 200 mg.kg-1 of Curosurf. Similarly, in near-term newborn rabbits with respiratory failure induced by instillation of fibrinogen via the airways, the increase in compliance after administration of 100 mg.kg-1 of SP-A-Curosurf corresponded to that seen after treatment with 200 mg.kg-1 of Curosurf, whereas Curosurf at a dose of 100 mg.kg-1 had no substantial effect. Our data thus indicate that surfactant protein A increases the resistance of Curosurf to inactivation under in vivo conditions.
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- ROBERTSON, B, et al.
(författare)
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Alveolar-to-vascular leakage of surfactant protein A in ventilated immature newborn rabbits
- 1995
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Ingår i: Biology of the neonate. - : S. Karger AG. - 0006-3126. ; 68:3, s. 185-190
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Tidskriftsartikel (refereegranskat)abstract
- We measured alveolar-to-vascular leakage of surfactant protein A (SP-A) in immature newborn rabbits delivered at a gestational age of 27 days. Experimental animals received, via a tracheal cannula, 2 ml/kg of a mixture of modified porcine surfactant (Curosurf, 80 mg/ml) and human recombinant SP-A (4 mg/ml). Littermate controls received the same volume of human SP-A in saline (4 mg/ml). After 30 min of artificial ventilation with a frequency of 40/min and an inspiration time of either 0.75 or 0.45 s, blood was sampled from the right ventricle and the lungs were lavaged. The content of human SP-A in serum and lung lavage fluid was determined with ELISA kits, and the alveolar-to-vascular leak expressed as the quotient of total SP-A in serum and lavage fluid. The leak in control animals amounted to about 2% of SP-A in lung wash and was several times higher in these animals than in those receiving surfactant. The leak was of the same order irrespective of whether the animals were ventilated with long or short inspiration time. We speculate that serum levels of SP-A may reflect the degree of lung injury in various forms of respiratory failure.
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