[Earliest appearance and morphologic picture of lamellar bodies in the amniotic fluid]

The alveolar lamellar bodies (LB), being the main source of the Surfactant-phospholipids, are produced by the alveolar cells of type II and excreted, during the development of the fetal lungs, in the alveolar space. Hence the LB move free, isolated or in groups, to the amniotic fluid, where they could be found as multilamellar structures. It is already being observed that the LB may be present in the amniotic fluid at the 32th or at the 26th week of pregnancy at the earliest. The method of centrifugation, which is very important for the evaluation of the LB, should always be considered. According to TEM research on the morphological development of the fetal alveolar epithel, there is also disagreement about the first production of Surfactant or LB from the alveolar cells of typ II. Our TEM-observations on two sediments of amniotic fluid from the 19th week of pregnancy (after centrifugation of the AF in 6000 revs/min) showed the presence of the alveolar lamellar bodies already in this week. A lot of different types of LB were observed, ranging of the most "immature" to types being empty at the interior with some peripheral membranes ("mature"). Occasionally osmiophilous nucleus was noticed inside the LB.