Time Course of Changes in Surface Tension and Morphology of Alveolar Epithelial Cells in CO2-induced Hyaline Membrane Disease *

the relationship between changes in lung surfac- tant and transformation of lamellar bodies in al- veolar cells during the uncompensated phase of C02-induced acidosis. MethodsMale guinea pigs of the Hartley strain weighing be- tween 400 and 600 g were exposed to 15% CO2 and 3% CO2 in air (21% 02) to follow up previous studies (4).* Based on examination with the light and electron microscope, the over-all number of granular pneumocytes did not appear to change through- out the experiment, although it is not possible to estimate the number of these cells per gram lung tissue.Data are means and standard deviations.t The number in parentheses represents the number of animals when different from the number listed in the first column.$ Film compressibility is [2 (y maximum --y minimum)]/[-y maximum + -y minimum].§ The number in brackets represents the number of sections counted.If Normal lamellar bodies contain very electron opaque material arranged in bars, clumps, or a myeloid pattern.If Abnormal lamellar bodies were without clearly defined electron opaque structures but may contain lipid droplets.** Statistically different from control at the 5% level and better.,