Quantitative Determination of Pulmonary Surfactant with Pulsating Bubble

Abstract

Surface-active lipids in alveolar wash were concentrated by centrifugation for 1 h, at 4 °C and 1000 X g. The resulting pellet was resuspended in a series of dilutions, and the surface properties of these suspensions were analysed with pulsating bubble. The pressure amplitude across the air-liquid interface of the pulsating bubble showed a statistically significant correlation with the phospholipid content of the sample at concentrations ≤ 0.27 mmol/P/l. The correlation between these two variables was negative, although statistically not significant, at higher phospholipid concentrations, probably due to overcrowding of the bubble wall with surface-active molecules.

Key Words:

• Alveolar wash
• phospholipids
• pulmonary surfactant
• pulsating bubble
• rat
• surface tension