title: Biophysical and physiological properties of porcine surfactant enriched with polymyxin B.
abstract: OBJECTIVE
  We examined whether the biophysical and physiological properties of Curosurf were improved by the cyclic amphipathic decapeptide polymyxin B (PxB).
  
  
  METHODS
  Curosurf was diluted to 1-5 mg/ml with PxB added at 1, 2 or 3% (w/w). Albumin was added at 40 mg/ml. Minimum surface tension (gammamin) during surface compression was determined for each mixture with pulsating bubble. Immature newborn rabbits were treated with 2.5 ml/kg of Curosurf 80 mg/ml, or Curosurf 32 mg/ml with or without 2% PxB and ventilated for up to 5 h.
  
  
  RESULTS
  At surfactant concentration 2 mg/ml, gammamin was high (17 +/- 8.9 mN/m) but remained low (2.7 +/- 0.8 mN/m) when PxB was added. Albumin inactivated Curosurf at both 2 and 3.5 mg/ml; this inactivation was prevented by 2% PxB. Treatment of newborn rabbits with Curosurf 80 mg/kg + 2% PxB significantly decreased incidence of pneumothorax in comparison with controls but had no significant effect on lung-thorax compliance or alveolar expansion.
  
  
  CONCLUSIONS
  Addition of 2% PxB improves surface activity of Curosurf at low concentration, increases its resistance to inactivation by albumin, and reduces the incidence of pneumothorax in immature newborn rabbits undergoing prolonged ventilation.
authors.affiliation: Laboratory for Surfactant Research, Department of Clinical Chemistry, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Calkovska
authors.forename: M
authors.initials: M
authors.lastname: Some
authors.forename: B
authors.initials: B
authors.lastname: Linderholm
authors.forename: J
authors.initials: J
authors.lastname: Johansson
authors.forename: T
authors.initials: T
authors.lastname: Curstedt
authors.forename: B
authors.initials: B
authors.lastname: Robertson
mesh_terms: D000280:Administration, Inhalation; D000418:Albumins / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D001688:Biological Products / Q000008:administration & dosage*; D008170:Lung Compliance / Q000187:drug effects; D008171:Lung Diseases / Q000188:drug therapy / Q000209:etiology / Q000517:prevention & control; D010743:Phospholipids / Q000008:administration & dosage*; D011112:Polymyxin B / Q000008:administration & dosage*; D011663:Pulmonary Surfactants / Q000008:administration & dosage*; D011817:Rabbits; D012121:Respiration, Artificial / Q000009:adverse effects; D013499:Surface Properties / Q000187:drug effects*; D013501:Surface-Active Agents / Q000008:administration & dosage*
chemical_list: D000418:Albumins; D001688:Biological Products; D010743:Phospholipids; D011663:Pulmonary Surfactants; D013501:Surface-Active Agents; D011112:Polymyxin B; C068291:poractant alfa