Elemental composition of lamellar bodies from fetal and adult XXXX lung.

@entity1 @entity38249 @entity1568 @entity141 @entity5987 @entity619 @entity35 @entity3151 @entity599 @entity1954
Previous studies in the @entity35 using electron probe microanalysis have suggested that most of the @entity141 in alveolar space is probably derived from secreted lamellar bodies (LB). However, the LB @entity141 content in cultured @entity35 type II cells is low and unaltered by @entity619 supplementation. In this study, we examined LB @entity141 content in adult @entity1 lung and cultured explants of fetal lung treated with hormones to promote type II cell differentiation. Lung tissue of 20 to 24 wk of gestation was cultured for 4 to 6 days without hormone and with @entity619 (10 nM), @entity1954 (2 nM), @entity5987 (0.1 mM), or their combinations. The cultured tissue samples were processed for light and electron microscopy or rapidly frozen and stored in @entity38249 under liquid @entity1568 . Thin cryosections from the frozen samples were prepared and examined using the electron probe microanalysis. @entity1 lung tissue up to 24 wk of gestational age had no detectable LB before explant culture. Explants cultured for 4 days without hormone supplementation (control) had no detectable LB, single-hormone treatments resulted in small LB, and combination treatments resulted in the formation of many large LB in explant type II cells. Despite such morphologic changes, LB @entity141 in both control and hormone-treated explants was low (overall mean, 4.1 +/- 0.6; P < 0.05) compared with LB of in situ @entity35 and adult @entity1 lung (30 +/- 2 and 27 +/- 1.5 mmol/kg dry wt, respectively) and was similar to that found in cultured @entity35 type II cells. LB @entity3151 and @entity599 under all explant culture conditions were comparable. These observations indicate that @entity1 and @entity35 LB elemental compositions are similar and that optimal in vitro conditions with respect to LB @entity141 metabolism have not been established.
