Figure 13.
Biophysical properties of surfactant from BALF under dynamic compression cycling. Minimum (A) and maximum (B) surface tension of control and MPS IIIA BALF surfactant samples expressed as mN/m. MPS IIIA animals have higher minimum surface tension, p < 0.003 (A), and higher maximum surface tension, p < 0.0115 (B). (C) Relative area of compression required to reach γmin was calculated as the percentage of area reduction needed to decrease the surface tension to the minimum value. Change in relative area in the 1st, 10th and 20th cycles was increased in MPS IIIA samples, * p = 0.0003, ** p < 0.0001. (D) Compressibility (ΔP/ΔA) was calculated as the slope value of the line passing through the minimum and maximum points of compression (minimum and maximum areas of the bubble) in the dynamic cycling curve (the steeper the slope, i.e., the higher the value, the lower the surfactant compressibility). * p = 0.0006, ** p = 0.0001, *** p < 0.0001. (E) Hysteresis was calculated as the enclosed area between the compression and expansion segments of the isotherms. * p = 0.0015, ** p = 0.0076. Data plotted as mean ± SD; two-tailed Students t-tests used for all analyses; n = 10 control and 6 MPS IIIA samples.