Linked Life Data

615509

Source:http://linkedlifedata.com/resource/pubmed/id/615509

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1978-9-15
pubmed:abstractText
Fetal growth in utero demands a continuous flow of water and solutes across the placental barrier. We investigated the membrane parameters that control the influx of solutes that are not actively transported and the influx of water. The osmotic conductivity, and the Na+ and Cl- permeabilities of the membrane were measured in chronically instrumented fetal sheep. Transplacental salt flow and water flow were augmented by drainage of fetal urine to the exterior over extended periods of time. Calculation showed that the membrane parameters are: deltaNaCl = 0.83, P.SNaCl = 8.0 10-3 ml.sec-1 kg-1, and LPS = 4.7 10-8 cm5.dyne-1.sec-1.kg-1 (placental surface area S being expressed per kg fetal weight). The chronic infusion of vasopressin into the fetuses at 8 to 11 units per day per kg fetal weight reduced the reflection coefficient deltaNaCl to a mean of 0.63 (P less than 0.03). We concluded that the characteristics of the influx of NaCl and water are compatible with those of a diffusion filtration process, that fetal growth is constrained by the diffusional permeability of the placenta for inert electrolyte and that in the long run fetal growth can only accelerate because placental electrolyte permeability increases. Vasopressin appears to reduce the salt reflection coefficient of the placenta thus enabling the fetus to exert some short term control over its acquisition of water and electrolyte.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0003-4193
pubmed:author
pubmed:issnType
Print
pubmed:volume
8
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
353-61
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1977
pubmed:articleTitle
Fetal homeostasis in relation to placental water exchange.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.