The human placenta. Anatomy and morphology.
ABSTRACT This review presents basic aspects of placental morphology with particular reference to the regional specialization of human placental tissues. Intrauterine visualization of the placenta is now possible with new non-invasive methods. Echotomographic ultrasound images of the placenta in vivo and in vitro are of the greatest value for clinical and pathological diagnosis. X-ray computed tomography, though it cannot be applied to pregnant women, is invaluable for the study of circulatory and pathologic changes in the placenta isolated post partum. Nuclear magnetic resonance imaging is another useful adjunct not only for placental localization but also to detect changes of placental morphology with an accuracy almost as good as ultrasonography. Fourier-transform spectroscopy now offers a unique opportunity to obtain computed biochemical data on the metabolic evolution of the human placenta.
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ABSTRACT: Pregnant mothers are exposed to a wide variety of foreign chemicals. This exposure is most commonly due to maternal medication, lifestyle factors, such as smoking, drug abuse, and alcohol consumption, or occupational and environmental sources. Foreign compounds may interfere with placental functions at many levels e.g. signaling, production and release of hormones and enzymes, transport of nutrients and waste products, implantation, cellular growth and maturation, and finally, at the terminal phase of placental life, i.e. delivery. Placental responses may also be due to pharmaco-/toxicodynamic responses to foreign chemicals, e.g. hypoxia. On the other hand, placental xenobiotic-metabolizing enzymes can detoxify or activate foreign chemicals, and transporters either enhance or prevent cellular accumulation and transfer across the placenta. The understanding of what xenobiotics do to the placenta and what the placenta does to the xenobiotics should provide the basis for the use of placenta as a tool to investigate and predict some aspects of developmental toxicity. This review aims to give an update of the fate and behavior of xenobiotics in the placenta from the viewpoint of xenobiotic-metabolizing enzymes and transporters. Their response levels will be described according to gestational status and methods used. The effects of foreign chemicals on placental metabolizing enzymes will be discussed. Also, interactions in the transporter protein level will be covered. The role of the placenta in contributing to developmental effects and fetotoxicity will be examined. The toxicological effects of maternal medications, smoking, and environmental exposures (dioxins, pesticides) as well as some possibilities for biomonitoring will be highlighted.Placenta 06/2005; 26(5):361-71. · 3.12 Impact Factor
- Arquivos de neuro-psiquiatria 01/2009; 66(4):876-8. · 0.55 Impact Factor
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ABSTRACT: Our objective was to study the endothelial status of the luminal lining of uteroplacental vessels in the human placental bed in normal and abnormal pregnancy in the third trimester. Six placental basal plates from uncomplicated pregnancies and five from pregnancies complicated by preeclampsia (n = 3), preeclampsia and a small-for-gestational-age infant (n = 1), and diabetes mellitus (n = 1) were accessioned from the archives because of documentation of their containing uteroplacental vessels. Five placental bed biopsy specimens with intraluminal endovascular trophoblast in the third trimester were also studied. Sections were subjected to immunohistochemical analysis with monoclonal and polyclonal antibodies labeling endothelium and trophoblast. In third-trimester normal uncomplicated pregnancies the uteroplacental arteries and veins were completely endothelialized with no disruption of the endothelium. In third-trimester abnormal pregnancies the uteroplacental veins were also completely endothelialized. However, intraluminal endovascular trophoblast was seen within the uteroplacental arteries in eight of the 10 complicated pregnancies; this finding was associated with disruption of the endothelium. In preeclampsia there is an aberrant wave of endovascular trophoblast migration in the third trimester, resulting in focal disruption of the endothelium. This may be responsible for the endothelial cell dysfunction thought to be of pathogenetic importance in preeclampsia.American Journal of Obstetrics and Gynecology 10/1992; 167(3):751-6. · 3.88 Impact Factor