Effect of liposomal encapsulation of chloramphenicol on its transfer across the human placenta in a dual in vitro perfusion system

The transfer rates and placental retention of a series of steroids were measured using an in vitro perfusion system of an isolated cotyledon of human placenta. The steroids were added to the maternal inflow and rates of appearance in maternal and fetal outflows were measured, from which data were calculated the transfer rate and placental retention. With a low concentration of albumin (0.01 g/dl) in the maternal and fetal perfusates, transfer rates of diethylstilbestrol and ethynylestradiol were initially low, with considerable retention of the steroids within the placenta. Transfer rates increased with duration of perfusion. With high concentrations of albumin (1 g/dl), placental retention was greatly reduced and transfer rates very rapidly reached high levels. Albumin in the fetal circulation was the effective factor in increasing transfer rate; maternal albumin reduced it. The results with estrone and progesterone were qualitatively similar but not as striking, posssibly because of the large endogenous concentrations of these two hormones. Placental retention of dexamethasone, a more polar steroid that does not bind to placenta and binds poorly to albumin, was low and there was little difference between transfer from low- and high-protein perfusates.

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Apoprotein C effect on triglyceride transport in tandem-perfused rat hind end and liver

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1984.247.3.g305 ◽

1984 ◽

Vol 247 (3) ◽

pp. G305-G310

Author(s):

W. J. Kortz ◽

J. R. Nashold ◽

M. R. Greenfield ◽

H. Hilderman ◽

S. H. Quarfordt

Keyword(s):

Fatty Acid ◽

Free Fatty Acid ◽

Fatty Acyl ◽

Liver Fat ◽

Molar Ratio ◽

Perfusion System ◽

In Vitro Perfusion ◽

Arterial Inflow ◽

High Concentrations

The metabolism of double-labeled triglyceride in a synthetic emulsion was defined in an in vitro perfusion system of rat hind end and liver described previously [Am. J. Physiol. 245 (Gastrointest. Liver Physiol. 8): G106-G112, 1983]. The metabolism of [3H]glycerol-[14C]triolein was defined in the absence of added apoproteins and with additions of human CII and both CII and CIII. Without apoprotein, a pronounced lipolysis of the triglyceride was recognized by high concentrations of radiolabeled glycerol and free fatty acid in the perfusate. The removal of an aliquot of hind-end venous effluent 5 min after adding the labeled triglyceride emulsion to the arterial inflow demonstrated a brisk lipolysis of the substrate when incubated outside the perfusion system. The addition of CII protein to the emulsion before its introduction into the tandem system eliminated perfusate lipolysis, both within the perfusion system and in incubations of aliquots withdrawn from the system. Intravascular lipolysis was not seen with triglyceride emulsions containing both CII and CIH or when an aliquot of hind-end venous effluent was incubated with triglycerides that had not been exposed to the perfusion system. The intravascular lipolysis observed for the [14C]triglyceride added to the tandem system without apoproteins was associated with relatively greater recoveries of 14C-fatty acyl in liver, fat, and muscle and relatively greater recoveries of 14CO2 than when CII alone or both CII and CIII were added with the triglyceride. The addition of CIII to CII in a 1:1 molar ratio increased the recovery of 14C-fatty acyl in muscle and the recovery as 14CO2.(ABSTRACT TRUNCATED AT 250 WORDS)

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