title: A method for the isolation and preparation of surfactant from tracheobronchial aspirates in infants and children for quantitative and pulsating bubble analysis.
abstract: A method is presented for the investigation of surfactant function after isolation and preparation of pulmonary surfactant from tracheobronchial aspirates of mechanically ventilated infants and children. This method involved purification of surfactant from contaminating non-surfactant phospholipids and mucus by sodium bromide density gradient centrifugation. The surfactant concentration in undiluted fluids (3.5 +/- 0.8 mg mL-1; mean +/- SD) was calculated by extrapolating from the urea concentration in aspirates and serum. Phospholipid concentration was adjusted to approximately 3 mg mL-1 and the surface activity was determined by means of a pulsating bubble surfactometer. Mean minimal and maximal tension values of all cycles were calculated after reaching steady state. Measurements obtained from surfactant isolated with this method showed a high reproducibility: the coefficient of variation for minimal surface tension was 6.1%. Therefore this method enables functional surfactant analysis in tracheobronchial aspirates.
authors.affiliation: Department of Pediatric Pneumology, Medical School Hannover, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Raymondos
authors.forename: I
authors.initials: I
authors.lastname: Martin-Carrera
authors.forename: W
authors.initials: W
authors.lastname: Bernhard
authors.forename: C
authors.initials: C
authors.lastname: Poets
authors.forename: H
authors.initials: H
authors.lastname: von der Hardt
mesh_terms: D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry*; D002648:Child; D002675:Child, Preschool; D005122:Exudates and Transudates / Q000737:chemistry*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D010743:Phospholipids / Q000032:analysis; D010827:Physiology / Q000379:methods; D011663:Pulmonary Surfactants / Q000302:isolation & purification*; D013500:Surface Tension; D014132:Trachea / Q000737:chemistry; D014508:Urea / Q000032:analysis
chemical_list: D010743:Phospholipids; D011663:Pulmonary Surfactants; D014508:Urea