The Human Placenta

Boyd, John; Hamilton, W. J.

doi:10.1007/978-1-349-02807-8

Cited by 621 publications

(75 citation statements)

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“…These extravillous trophoblast cells continue to invade the endometrial stroma and uterine vasculature in macaques, baboons, and humans (Boyd and Hamilton, 1970;Ramsey et al, 1976;Ramsey and Donner, 1980;Enders and King, 1991;Blankenship et al, 1993a,b). We have previously shown in macaques that the maternal vascular system is invaded by trophoblast very early in gestation (Enders and King, 1991).…”

Section: Discussionmentioning

confidence: 99%

“…In their extensive monograph on human placentas, Boyd and Hamilton (1970) begin their discussion on mechanisms of placental growth (page 138) by writing "The mechanism of placental growth, if not altogether a n intransigent problem, is one to which much further attention will have to be given before a fully satisfactory explanation is forthcoming. Sufficient information is not currently available to permit an adequate analysis of all the factors concerned."…”

Section: Discussionmentioning

confidence: 99%

“…The villi are covered by a layer of syncytiotrophoblast, which is subtended by a single layer of cytotrophoblast cells that are apposed to the villous mesenchymal core. The intervillous space, delimited by these placental compartments, contains the maternal blood which circulates through the placenta (for reviews of placental structure see Boyd and Hamilton, 1970;Benirschke and Kaufmann, 1990;King and Blankenship, 1993). The elaboration of this complex structure and its continued growth throughout pregnancy is a poorly understood process.…”

Section: Introductionmentioning

confidence: 99%

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Developmental expression of Ki‐67 antigen and proliferating cell nuclear antigen in macaque placentas

Blankenship

King

1994

Developmental Dynamics

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Placental growth is largely determined by the proliferation of cytotrophoblast cells. However, the distribution of cytotrophoblast cells engaged in the cell cycle during placental development is poorly understood. Recently, antibodies have been developed that identify two proteins directly involved with DNA synthesis: Ki-67 protein and proliferating cell nuclear antigen (PCNA). Immunolocalization of Ki-67 and PCNA provides a measure of the proliferating cells in tissues. We examined, in macaque placentas, the spatiotemporal pattern of expression of these proteins during gestation. Tissues from 24 macaque placentas collected from 22-153 days of pregnancy were prepared for paraffin sections. Standard immunoperoxidase techniques were used to identify Ki-67 and PCNA. The proteins generally co-localized, although PCNA was usually represented in more cells than Ki-67. Early in gestation the cell columns contained many labeled cells. The cytotrophoblastic shell was occupied by numerous cells with PCNA positive nuclei, but few were reactive for Ki-67. By 45 days of pregnancy the immunolabeled cells in the cell columns were concentrated in the proximal regions, adjacent to the anchoring villus tips. The number of positive cells decreased by 100 days when the cell columns were diminished, leaving the anchoring villus tips buried in the shell. Labeled cells were rarely present in the shell at late pregnancy. The single layer of cytotrophoblast cells in the chorionic plate contained numerous reactive cells throughout early and mid-gestation. After approximately 100 days the cytotrophoblast layer of the chorionic plate was stratified over large areas. Soon thereafter few cells of the chorionic plate were labeled. The chorionic villi contained reactive cytotrophoblastic cells throughout gestation. Extravillous cytotrophoblast cells invading spiral arteries were sometimes labeled for PCNA but not Ki-67. We conclude that compartments of the placenta are distinguished by specific patterns of cytotrophoblast cell proliferation. Moreover, these patterns correspond to macroscopic growth parameters of the placenta. Evidence suggests that the macaque placenta slows its rate of diametrical growth at approximately 100 days of gestation. It is at about this time that the cell columns are absorbed into the trophoblastic shell and this pool ofproliferating cells is diminished. The growth in diameter of the chorionic plate matches that of the shell. In this compartment also the architecture changes at about 100 days as the cytotrophoblast layer stratifies. This stratification may result from continued proliferation of cytotrophoblast cells when the diametrical rate of growth is decreasing. Soon thereafter, proliferation decreases in this compartment also. By contrast, labeled cells were found in chorionic villi throughout gestation. Continued villous growth and branching probably accounts for most of the increases in placental thickness and weight that occurs during late gestation. 0 1994 Wiley-Liss, Inc.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Developmental expression of Ki‐67 antigen and proliferating cell nuclear antigen in macaque placentas

Blankenship

King

1994

Developmental Dynamics

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“…A correct distribution and amount of these carbohydrate moieties might have an important role in maintaining the integrity of the components of the jelly as well as in metabolic processes, thus permitting the jelly to play its physiological functions, as the protection of the vessels from inelasticity and compression and the diffusion of substances in particular from the vein to the arteries [22,23]. Moreover, the stromal cells seem to play a role in regulating of the umbilical cord blood flow, since these cells have characteristics of fibroblasts and smooth muscle cells [24].…”

Section: Discussionmentioning

confidence: 99%

“…As it occurred in the jelly, the oligosaccharides present in the vessels might have a role in maintaining the structure and the metabolic processes of their components and thus permitting to play their physiological functions as the diffusion of substances and the regulation of the blood flow, due to the smooth muscle cells [23]. Moreover, the endothelial cells seem to play a role in transmitting signals coming from the blood flow to the muscle cells, for the regulation of the contractions and the remodelling of the vessels [34].…”

Section: Discussionmentioning

confidence: 99%

Lectin binding in the umbilical cord in altered glycemia

Sgambati

Marini

Thyrion

et al. 2007

European Journal of Obstetrics & Gynecology and Reproductiv

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Objective: Content and distribution of the oligosaccharides in the umbilical cord from pregnancies with altered glycemia were investigated. Study design: A prospective cohort study was conducted in the Florence Policlinic of Careggi, Italy. Samples of cord from physiological pregnancies (n = 20), from pregnancies with minor degree of glucose intolerance (n = 20) and from pregnancies with gestational diabetes mellitus (GDM) treated with insulin (n = 20) were collected. Eleven lectins were used (ConA, WGA, PNA, SBA, DBA, LTA, UEA I, OOA, GSL II, MAL II and SNA) in combination with chemical and enzymatic treatments. Results: Increase of N-acetyl-D-glucosamine and a loss of sialic acid in the umbilical cord of the cases with minor degree of glucose intolerance with respect to the other study groups was observed. D-Galactose(b1 ! 3)-N-acetyl-D-galactosamine, N-acetyl-D-galactosamine and L-fucose were in less amount in both the pathological groups with respect to the control one. Conclusion: The increase of some glycoconjugates carbohydrates and the loss of others in the umbilical cord from pregnancies with minor degree of glucose intolerance might be related to its morphofunctional alterations in a not diabetic altered glycemia. Moreover, the treatment with insulin in the GDM might play a role in restoring partially the normal glycosilation in the cord components in the attempt to renew some their functions. #

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Prenatal Diagnosis of Trisomy 18

Hsu¹

1973

Am J Dis Child

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The Human Placenta

Cited by 621 publications

References 0 publications

Developmental expression of Ki‐67 antigen and proliferating cell nuclear antigen in macaque placentas

Developmental expression of Ki‐67 antigen and proliferating cell nuclear antigen in macaque placentas

Lectin binding in the umbilical cord in altered glycemia

Prenatal Diagnosis of Trisomy 18

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