HUMAN PLACENTAL PERMEABILITY TO HYDROPHILIC MATERIALS

    Project: Research project

    Description

    Previous work from this laboratory has shown that the hemochorial placentas
    of the rabbit and the guinea pig do not strongly discriminate molecular
    size. It is also known that the epitheliochorial placenta of the sheep so
    strongly discriminates size that the placenta is essentially opaque to
    hydrophilic materials of greater than 200 molecular weight. It is the
    purpose of this proposal to prove our hypothesis that the permeability
    characteristics of the human placenta will be like those of the other
    hemochorial placentas and not like those of the placenta of the sheep.
    Nontoxic, nonradioactive, and metabolically inert tracers will be given
    i.v. to pregnant women shortly before their scheduled elective cesarean
    sections. At the time of birth, fetal tracer contents will be estimated
    from fetal plasma concentrations and an approximation of the distribution
    volume of the tracer and/or from the integral collection of fetal urine
    until all tracer has been excreted. The timing of the injections will be
    such that at birth fetal plasma concentrations will be less than 10% of the
    final maternal plasma concentrations. The transplacental concentration
    difference is therefore essentially equal to the maternal plasma
    concentration. The quantitative results from this study should be of help
    in calculating fetal drug exposures when hydrophilic drugs are present in
    maternal plasma in known concentrations. They should also allow the
    construction of a more accurate theoretic model for prenatal water
    transfer, and thus help elucidate the pathophysiology of hydrops fetalis.
    StatusFinished
    Effective start/end date9/30/828/31/88

    Funding

    • National Institutes of Health
    • National Institutes of Health

    Fingerprint

    tracers
    permeability
    sheep
    drugs
    guinea pigs
    rabbits
    proposals
    molecular weight
    time measurement
    injection
    approximation

    ASJC

    • Medicine(all)