A system is described for the extracorporeal perfusion of the human foeto-placental unit at midgestation. The same system is used for the perfusion of isolated midgestation foetuses and midgestation or term placentas.
Various gas mixtures were used for the oxygenation of the blood to be perfused, and the pH, pO2 and pCO2 values were monitored at frequent intervals in the perfused blood as well as in the various perfusates. Compared with the values reported for maternal arterial blood, oxygenation of the blood to be perfused with an air + CO2 mixture (23.1 % O2 + 3.5–3.7 % CO2) yielded a normal pH and almost normal pO2 and pCO2 values, whereas oxygenation with carbogen (93.7 % O2 + 6.3 % CO2) resulted in low pH, highly elevated pO2 and almost normal pCO2 values.
In all foetal, placental and foeto-placental perfusions conducted at 36°C, the use of blood oxygenated with the air + CO2 mixture resulted in significantly better pH, pO2 and pCO2 values of the perfusates than when blood oxygenated with carbogen was employed. However, the pH, pO2 and pCO2 values in the perfusates obtained in the former series of experiments were still outside the range of normal values reported in the literature.
As the first part of a series of investigations on acetate and cholesterol metabolism, the conversion of acetate to cholesterol was studied in the various compartments of the midgestation foeto-placental unit in perfusion experiments carried out for 90 min at 35–36°C.
Following their removal at laparotomy two complete foeto-placental units were perfused each with 5.0 mCi of uniformly labelled sodium acetate-14C + 5.0 mCi of cholesterol-7α-3H. The study was completed by the separate perfusion of two isolated midgestation foetuses and two midgestation placentas. The doses administered in each of these four last experiments were 2.5 mCi of 14C-labelled acetate and 2.5 mCi of 3H-labelled cholesterol.
Cholesterol was isolated in a radiochemically homogeneous form from each of the tissues studied.
The cholesterol isolated from the placentas, placental perfusates and from the blood bathing the placenta from the maternal side (»maternal perfusates«) contained exclusively 3H-label. On the other hand, the cholesterol isolated from all foetal livers, adrenals, testicles, 3 of 4 residual foetal tissues and 1 out of 4 foetal perfusates also contained significant quantities of 14C-label.
It is concluded, that the midgestation human placenta is not capable of synthesizing cholesterol from acetate, but that the conversion of acetate to cholesterol is a quantitatively significant metabolic pathway in the human foetus at midgestation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.