In vivo permeability of the human placenta to inulin and mannitol.

Bain, Murray D.; Copas, D K; Landon, Michael; Stacey, T. E.

doi:10.1113/jphysiol.1988.sp017082

Cited by 32 publications

(19 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The study population, procedures for maternal infusion, sample preparation and neonatal urine collection have been described previously (Bain et al 1988). In brief, a bolus followed by a constant infusion was started 1-2 h before the scheduled time of delivery in a group of women for whom delivery was to be by elective Caesarean section at term for reasons unrelated to fetal or maternal disease.…”

Section: Clinicalmentioning

confidence: 99%

“…There are very few data on the in vivo passive permeability characteristics of the human placenta. The studies with inulin and mannitol (Bain, Copas, Landon & Stacey, 1988) on the one hand and cyanocobalamin (Willis, O'Grady, Faber & Thornburg, 1986) or inulin (Thornburg, Burry, Adams, Kirk & Faber, 1988) on the other used two different experimental methods and slightly different results were obtained. Though a 'notional pore radius' could be derived (Bain et al 1988) there were too few permeants to determine whether or not the pores were uniporous.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Permeability of the human placenta in vivo to four non‐metabolized hydrophilic molecules.

Bain¹,

Copas²,

Taylor³

et al. 1990

The Journal of Physiology

Self Cite

View full text Add to dashboard Cite

SUMMARY1. Permeability of the human placenta to four permeants of different molecular size was measured at Caesarean section in seven normal full-term pregnancies.2. Placental clearance for mannitol was 8-7+1I1 ml min-' (mean+s.E.M.), lactulose 6-3 + 0-8, chromium ethylenediaminetetraacetic acid (CrEDTA) 3-7 + 0 5, and inulin 0-98+041.3. The permeability data were analysed in terms of restricted diffusion through 'notional' water-filled pores and found to be incompatible with a single population of uniform pores.

show abstract

Section: Clinicalmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Permeability of the human placenta in vivo to four non‐metabolized hydrophilic molecules.

Bain¹,

Copas²,

Taylor³

et al. 1990

The Journal of Physiology

Self Cite

View full text Add to dashboard Cite

show abstract

“…The human placenta lacks a lymph drainage system and in other species this has been associated with the fetal endothelium providing most of the resistance to the transplacental transfer of large molecules (Thornburg & Faber, 1976;Boyd, Canning, Stacey, Ward & Weedon, 1983). In vivo transfer data in human placenta (Bain, Copas, Landon & Stacey, 1988;Bain, Copas, Taylor, Landon & Stacey, 1990) would lend support to the conclusion that the endothelium exerts a major regulatory role in transplacental transfer.…”

Section: Discussionmentioning

confidence: 96%

Permeability of the fetal villous microvasculature in the isolated perfused term human placenta.

Eaton

Leach

Firth

1993

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. Capillary permeability-surface area (PS) products for the low molecular weight radioactive tracers, 22Na, 5"Cr-EDTA (relative molecular mass 357) and 57Co-cyanocobalamin (relative molecular mass 1353) were measured in the fetal circulation of isolated dually perfused lobules of normal term human placentae using the single circulation, multiple-tracer dilution technique.2. In lobules perfused with M199 medium, containing dextran and 5 g I`bovine albumin, the extractions of all three tracers decreased as the flow was increased over the range of 2-8 ml min-', and PS products for 5"Cr-EDTA and 57Co-cyanocobalamin, but not for 22Na, reached constant values at flows above 01 ml min-' g-1.3. Flow-independent PS products in the presence of albumin were 0-025 + 0-002 ml min-' g-1 (mean±+ S.E.M., n = 25) for 57Co-cyanocobalamin and 0057 + 0003 ml min-' g-1 (n = 25) for 51Cr-EDTA. The ratio of PS values (51Cr-EDTA/57Co-cyanocobalamin) was 2 28, while the ratio of the corresponding free diffusion coefficients was 179, indicating substantial restriction to the diffusion of the 57Co-cyanocobalamin. 4. In another series of lobules perfused in the absence of albumin, extraction values for all three test tracers were constant over the same flow range. Values at high flow rates were therefore about twice those measured in the presence of albumin, and PS products for all three tracers failed to reach diffusion-limited values.6. Lobules perfused with and without albumin were fixed using a glutaraldehyde fixative containing 1 % Alcian Blue dye. An ultrastructural examination of the endothelium showed no significant changes in cell or cleft morphology, or in the glycocalyx, in the absence of albumin which might account for the observed permeability change.7. These data are the first physiological measurements specifically characterizing fetal microvascular permeability in the human placenta. The results suggest that permeability resembles that found in skeletal muscle and, as such, the endothelium presents a significant barrier to the diffusion of large solutes. The observed 'protein effect' indicates that albumin can interact with elements of the solute pathway to increase its restrictiveness.

show abstract

“…69000 Da) and bovine IgG (mol. wt 169000 Da) only cross the placenta in traces (Dancis et a1 1976;Contractor & Stannard 1983;Contractor et a1 1984;Bain et al 1988). On the other hand substances of lower mol.…”

Section: Discussionmentioning

confidence: 99%

Transfer of Heparin Across the Human Perfused Placental Lobule

Bajoria

Contractor

1992

Journal of Pharmacy and Pharmacology

View full text Add to dashboard Cite

A system of dual perfusion of an isolated lobule of term human placenta was used as a model to study the transfer of heparin from maternal to foetal circulation. The metabolic viability of the system was assessed by measuring beta-HCG and alkaline phosphatase levels in both maternal and foetal perfusates. Creatinine and antipyrine were used as markers to determine juxtaposition of the maternal and foetal circulations. Results of this study indicate that following administration of a single bolus dose of heparin into the maternal circulation, its concentration declined slowly from 99.01 +/- 2.98 at 15 min to 97.23 +/- 4.12% and transfer of heparin in the foetal circulation was linear and increased from 0.10% +/- 0.05% at 15 min to 0.46 +/- 0.19% over a period of 120 min. The maternal (MAUC) and foetal (FAUC) concentration-time integrals were found to be 70160 +/- 1332 and 340 +/- 30 int. units min mL-1, respectively. Placental permeability of heparin and creatinine, calculated as the ratio of foetal concentration to the integral maternal-foetal concentration difference, was 8.65 x 10(-5) +/- 0.80 x 10(-5) and 0.033 +/- 0.006 mL min-1 g-1 of perfused placental weight, respectively. These data suggest that heparin was transferred from the maternal to the foetal circulation in small quantities.

show abstract

In vivo permeability of the human placenta to inulin and mannitol.

Cited by 32 publications

References 10 publications

Permeability of the human placenta in vivo to four non‐metabolized hydrophilic molecules.

Permeability of the human placenta in vivo to four non‐metabolized hydrophilic molecules.

Permeability of the fetal villous microvasculature in the isolated perfused term human placenta.

Transfer of Heparin Across the Human Perfused Placental Lobule

Contact Info

Product

Resources

About