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PubMed1978

Quantitative morphology of the placenta. II. The growth of the placenta and the problem of postmaturity.

The morphological changes in the placenta concomitant with the transition from maturity to postmaturity were investigated by stereology under early clamping of the umbilical cord. 37 placentas from nonpathological pregnancies delivered after a period of 224-303 days of amenorrhea were examined. It appeared that after 267-288 days of amenorrhea, 8 out of 9 placental components showed no further growth and even showed regression. Only the volume of the trophoblast continued to grow in postmaturity. It is suggested that during postmaturity the villous capacity to produce steroids is continuing at a normal rate (as judged by the increase of the volume of the trophoblast), whereas the capability to transfer is deteriorating (as testified by the decreasing surface of the trophoblast).

Chorionic Villi↗
PubMed1978

Quantitative morphology of the placenta. III. The growth of the placenta and its relationship to birth weight.

The relationship of placental components to birth weight was investigated by stereology. 37 placentas from nonpathological pregnancies delivered after a period of 224-303 days of amenorrhea were examined. The umbilical cord was clamped immediately after birth. The ratios of the volume, the surface, the length of the villous vessels and the surface of the villi with birth weight showed a decrease after 277 days of amenorrhea. In contrast to this decrease, the ratio of the volume of the trophoblast with birth weight seems to increase. No difference could be found for the ratios of the placental volume (placental index), the volume of the villous tissue, the volume of the intervillous space and the volume of the nonfunctional tissue with birth weight. These ratios reveal a quantitative morphological base for the clinical experience that postmature fetuses are at a higher risk through deterioration of the placenta.

Birth Weight↗
PubMed2006

Phthalate monoesters in perfusate from a dual placenta perfusion system, the placenta tissue and umbilical cord blood.

Fetal exposure to phthalates may be associated with adverse reproductive effects, including cryptorchidism and decreased semen quality. Information about human placental transfer is needed to qualify the hypotheses. A dual recirculating placenta perfusion system to monitor concentrations of eight phthalate monoesters in fetal and maternal perfusates was established. In addition to perfusate background measures of phthalate monoesters, the concentrations in umbilical cord plasma and placenta tissue were measured. Monomethyl phthalate (mMP), monoethyl phthalate (mEP), monobutyl phthalate (mBP), and mono (2-ethyl-hexyl) phthalate (mEHP) were detected in both maternal and fetal perfusate, demonstrating a release of compounds from tissue or blood to perfusates. The distribution of compounds between perfusate, umbilical cord plasma, and tissue was in accordance with the physical-chemical properties of the compounds. Results from the present study of compounds residing in the tissue are essential before studying human transplacental transfer, storage, and metabolism of selected phthalate monoesters.

Adult↗
PubMed2001

Human placenta as a 'dual' biomarker for monitoring fetal and maternal environment with special reference to potentially toxic trace elements. Part 2: essential minor, trace and other (non-essential) elements in human placenta.

A survey of elemental composition of the human placenta was undertaken to evaluate reference values for minor and trace elements (essential and non-essential). The new data collection was narrowed down to results generated between the period of 1975-2000, since analytical methodology was becoming increasingly reliable with time for many elements. The search revealed the following results (microg/g, based on wet weight): Ca = 770; Cl = 1900; K = 1685; Mg = 100; Na = 360; P = 1700; and S = 350. However, Na, P and S need further confirmation. For a group of essential trace elements following average values were evaluated (microg/g, based on wet weight): Co = 0.007; Cr = 0.03; Cu = 0.9; Fe = 69; I = 0.005; Mn = 0.08; Mo = 0.02; Se = 0.2; and Zn = 10. However, the iodine value needs further confirmation. In addition, information values have been identified for a number of so-called non-essential elements such as Ag, Au, B, Ba, Br, Cs, F, La, Rb, Sb, Sc, Si, Sn, Sr, Ti, V and W. The survey results for toxic trace elements As, Cd, Hg, Ni and Pb are discussed in part 3 of this paper along with placenta as a biomonitor for toxic trace elements.

Adult↗
PubMedDate not supplied

Histidine transfer across the human placenta: characteristics in the isolated perfused human placenta and the effect of ethanol.

Histidine is essential to normal fetal growth. In vivo, the fetal-to-maternal (F-to-M) plasma concentration ratio for histidine is the highest of any amino acid. Previously, we have shown that histidine uptake by human placental microvillous membrane vesicles (MMV) occurs by a specific, Na(+)-dependent system. In this study, we have examined the maternal-to-fetal (M-to-F) transfer characteristics of histidine, using the isolated perfused human placental cotyledon. In addition, the effect of ethanol on net transfer of histidine in this human tissue model has been assessed. During 4 h of perfusion a 1.8:1 fetal-to-maternal perfusate ratio formed for histidine. In the perfused placentae, net M-to-F transfer of histidine was saturable with an apparent Km of 0.09 mM. The perfusion experiments suggest that the F-to-M histidine gradient observed in vivo is due primarily to active transport across the placenta. The presence of 300 per cent (65 mM) ethanol in the maternal perfusate did not alter the transfer characteristics of histidine, nor that of the diffusion markers, antipyrine and L-glucose.

Antipyrine↗
PubMed1977

Oncornavirus-like particles in squirrel monkey (Saimiri sciureus) placenta and placenta culture.

Oncornavirus-like particles similar in morphology to type D particles were observed in 1 of 2 squirrel monkey (Saimiri sciureus) placentas. Intracytoplasmic type A particles, immature virus particles, and mature viruses with eccentric or occasionally centric nucleoids were associated with placental syncytiotrophoblasts. A spike layer typical of type B viruses was not detected in viral envelopes. Onvornaviruses, identical to those previously isolated from squirrel monkey tissues and similar to Mason-Pfizer monkey virus, were seen in cultures derived from the virus-positive squirrel monkey placenta cocultivated with a mink lung culture. The major morphologic difference between the in vivo and the in vitro squirrel monkey virus was in the nucleoid position of mature virus particles.

Animals↗
PubMed2001

Expression profiles of interleukin-15 in early and late gestational human placenta and in pre-eclamptic placenta.

The presence of interleukin-15 (IL-15) mRNA in human placenta has been demonstrated previously. The present study was undertaken to investigate the expression profiles of IL-15 mRNA and protein in early and late gestational placental tissues, and also the effect of labour on its production. Levels of placental IL-15 expression were also determined in patients presenting with pre-eclampsia. An explant culture system was used to study the release of immunoreactive IL-15 by the placental tissues. Enzyme-linked immunosorbent assays were employed to quantify concentrations in the culture medium. The results showed that placental tissues from all groups released immunoreactive IL-15 into the culture medium. Moreover, the level of secretion by the term placental tissues was much higher than that by first trimester tissues. The presence of labour at term resulted in a further increase in placental IL-15 production. Reverse transcription-polymerase chain reaction (RT-PCR) was used to demonstrate the expression of IL-15 mRNA in these tissues. The results confirmed the expression of IL-15 in placenta from all the groups and the mRNA levels in the samples was highly correlated with the respective protein concentrations. Levels of both IL-15 mRNA and protein were significantly reduced in the pre-eclamptic placental tissue compared with the normal controls. The present study suggests an important role for this novel cytokine in human pregnancy.

Culture Media↗
PubMed2001

Heme oxygenase expression in human placenta and placental bed: reduced expression of placenta endothelial HO-2 in preeclampsia and fetal growth restriction.

In this study we tested the hypothesis that expression of heme oxygenases HO-1 and HO-2, which are responsible for the production of carbon monoxide, are reduced in the placenta and placental bed of pregnancies complicated by preeclampsia (PE) and fetal growth restriction (FGR) compared with control third-trimester pregnancies. Placental protein expression was determined by Western blotting (n=10 in each group) and immunohistochemistry (controls n=18, PE n=19, FGR n=10). Extravillous trophoblast expression was determined by immunohistochemistry of placental bed biopsy samples (controls n=17, PE n=19, FGR n=10). Western blot analysis of placental homogenates showed no overall differences in HO-2 among groups. However, immunohistochemical analysis showed a reduction in HO-2 expression in endothelial cells in both abnormal groups (PE P<0.01; FGR P<0.0005 vs. control group) but no differences in villous trophoblast staining. HO-1 was undetectable by Western blotting in control and abnormal pregnancies and immunoreactivity was very low, suggesting that there is little HO-1 in the placenta. Within the placental bed, HO-2 but not HO-1 was detected on all populations of extravillous trophoblast, but expression of HO-2 or HO-1 did not change in PE or FGR. The reduced expression of HO-2 on endothelial cells in PE and FGR may be responsible for reduced placental blood flow in these conditions. The data do not show changes in HO in the placental bed in PE or FGR.

Adult↗
PubMed1993

Characterization of cardiac fatty-acid-binding protein from human placenta. Comparison with placenta hepatic types.

When a 105,000 x g supernatant of human placenta was incubated with [1-14C]oleate and subjected to Sephadex G-75 gel filtration and HPLC, two fatty-acid-binding protein (FABP) peaks were obtained. One of these, when further purified by carboxymethyl-cellulose, gave one 15.3-kDa FABP with pI5.3. The other, when chromatographed on DEAE cellulose, separated into two 14.2-kDa FABP with pI6.9 and 5.4. Purity of the proteins was checked by SDS/PAGE. Molecular mass, pI, immunochemical properties and amino acid compositions all indicated that 15.3-kDa FABP was of the cardiac type, whereas both 14.2-kDa FABP were of the hepatic type. Cardiac FABP did not cross-react with hepatic proteins. When tested for the acceptor/donor properties of these FABP, hepatic types were found to be better candidates than cardiac in uptaking fatty acids from liposomes. Cardiac FABP, on the other hand, acted in a more efficient way as a donor, indicating a distinct role of these proteins in human placenta, which furnishes a multiorgan system for the developing fetus.

Amino Acids↗
PubMed1998

Intra-umbilical vein injection and retained placenta: evidence from a collaborative large randomised controlled trial. Grupo Argentino de Estudio de Placenta Retenida.

OBJECTIVE: To determine whether intra-umbilical vein injection with saline solution, with or without oxytocin, reduces the need for manual removal of placenta compared with expectant management. DESIGN: Multicenter, randomised controlled trial. SETTING: Eleven hospitals in four cities of Argentina: Buenos Aires, Corrientes, Rosario, and Salta. PARTICIPANTS: Two hundred and ninety-one women showing no evidence of placental separation thirty minutes after vaginal delivery. INTERVENTIONS: Three different management strategies: 1. intra-umbilical vein injection of saline solution plus oxytocin; 2. intra-umbilical vein injection of saline solution alone; and 3. expectant management. MAIN OUTCOME MEASURES: Primary: manual removal of the placenta. Secondary: blood loss after trial entry, haemoglobin level at 24 to 48 hours and at 40 to 45 days after delivery, blood transfusion, curettage, infection, and days of hospital stay. RESULTS: Rates of subsequent manual removal were similar: intra-umbilical vein injection of saline solution plus oxytocin (58%; RR 0.92; 95% CI 0.73-1.15), or saline alone (63%; RR 1.00; 95% CI 0.80-1.24), compared with expectant management (63%). There were also no detectable effects of the active managements on any of the secondary measures of outcome. CONCLUSIONS: Based on evidence available from randomised controlled trials, including this trial, it is unlikely that intra-umbilical injection with or without oxytocin, is clinically useful. We recommend that this intervention should not be used in third stage management of labour.

Female↗
PubMed1985

Immunoactive products of placenta: VIII. Translation products of messenger RNA extracted from murine placenta or A6B9IC5 teratocarcinoma are immunosuppressive in vitro.

RNA was extracted from placentae of synpregnant C3H mice (day 14 of gestation) and from A6B9IC5 teratocarcinoma. After isolation of poly-(A)+ RNA on an oligo d(T) cellulose column, putative messenger RNA was injected into Xenopus laevi oocytes. Supernatants and homogenates from the oocytes were assayed for immunoregulatory activity in MLR, CML, and NK assays and found to be immunosuppressive. These data indicate that immunomodulators could be obtained from the placenta by molecular biology technology in sufficient quantities for eventual clinical applications.

Animals↗
PubMed1999

Goat fetuses disconnected from the placenta, but reconnected to an artificial placenta, display intermittent breathing movements.

To investigate whether placental factors are involved in the intermittent breathing movements in goat fetuses, we assessed electrocortical activity (ECoA) and tracheal pressure in 5 fetuses (124-135 days) separated from the placenta and connected for 48 h to an extrauterine fetal incubation system that provided umbilical arteriovenous extracorporeal membrane oxygenation. The fetal physiological condition on this system was almost the same as that in utero for at least 48 h after the preparation. All fetuses showed intermittent low-voltage ECoA and breathing movements. The breathing movements occurred almost exclusively during periods of low- voltage ECoA. The proportions of time spent in low-voltage ECoA and breathing movements were 48-57% and 46-56%, respectively. In conclusion, breathing movements of fetuses on the extrauterine incubation system were episodic, suggesting that intermittent breathing movements are intrinsic to fetuses, independent of placenta-derived factors.

Animals↗
PubMed2005

Distribution of PCDDs/PCDFs and Co-PCBs in human maternal blood, cord blood, placenta, milk, and adipose tissue: dioxins showing high toxic equivalency factor accumulate in the placenta.

To assess levels of dioxin background contamination and transfer of dioxins from mothers to unborn children and infants, concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar-polychlorinated biphenyls (Co-PCBs) were measured in human samples from expectant and nursing mothers living in Nara, Japan. The average toxic equivalency quantities (TEQs) of PCDDs/PCDFs and Co-PCBs from circulating maternal blood, cord blood, placenta, milk taken 3-10 d after delivery, milk taken one month after delivery, and adipose tissue were 26 and 9.3, 15 and 2.3, 31 and 1.2, 16 and 5.4, 18 and 8.8, and 16 and 7.7 pg-TEQ/g-fat, respectively. Among the various PCDD/PCDF congeners, 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF contributed most heavily to the TEQs of all maternal samples. Among the various Co-PCB congeners, 3,3',4,4',5-PeCB (#126), 2,3,3',4,4',5-HxCB (#156), and 2,3',4,4',5-PeCB (#118) contributed most heavily to the TEQs of all maternal samples. But, the concentrations and relative percentages of congeners differed among the various samples, suggesting that congeners showing high toxic equivalency factor accumulate in the placenta.

Adipose Tissue↗
PubMed1977

Ultrastructure of the human placenta at term. Observations on placentas from newborn children of smoking and non-smoking mothers.

The placenta was chosen as a possible model for evaluating the vascular injury and tissue injury provoked by tobacco smoking in the human body. Full term placentas from 4 smokers and 3 non-smokers were studied in the transmission electron microscope. Pronounced changes were found in the group of smokers. The characteristic findings were broadening of the basement membrane of the placental villus, increase in collagen content of the villus, decrease in vascularisation and intimal changes in the villous capillaries and arterioles, with pronounced intimal oedema. Since similar changes have been reported previously from human umbilical arteries, and since these changes also can be induced in animal arteries by exposure to carbon monoxide or perfusion with nicotine, this study supports the concept that tobacco smoking is harmful to the human vascular system and tissues.

Adolescent↗
PubMed1980

Water and ion metabolism in placenta (III). Net movement of water, monovalent and divalent cations in slices from rabbit placenta, at different periods of gestation, incubated under metabolically favorable conditions.

Rabbit placenta slices incubated at 38 degrees C in oxygenated medium, in the presence of endogenous substrates +5 mM glucose, after a period of preincubation of 120 min at 0--1 degrees C, show a net accumulation of potassium and extrusion of water, sodium and calcium. The movement of potassium, sodium and calcium appears to be related to the rate of oxygen consumption of the slices and to be inversely proportional to the age of the tissue. The efficiency of cations movement is also dependent on the nature and composition of the incubation medium. In this respect the potassium concentration of the medium plays a major role. The movement of water, on the other hand, seems to be completely independent from both the rate of respiration and the age of the tissue. The results are discussed in terms of relation between placenta age and senescence, and efficiency of the mechanisms devoted to the cell regulation of water and ions content.

Animals↗
PubMed1991

[Comparative study of dopplerometry and morphological study of placenta and uterine arteries in the evaluation of hemodynamic disorders in the "mother-placenta-fetus" system].

The paper gives the comparative results of Doppler examination of blood flow in the mother-placenta-fetus system and morphological examination of the vessels of the funis, placenta, and placental bed. The latter examination allowed all the cases of placentomaternal and placentofetal circulatory diseases to be divided into 3 groups. There was a clear-cut correlation between the Doppler metric and morphological findings.

Adult↗
PubMed1990

[Pathology of the placenta. II. Malformations of the umbilical cord and the placenta].

Malformations of both the umbilical cord and placenta are covered in the second part of this account of placental pathology. Disorders in placental development are subdivided on the basis of the classification published by Vogel (1984). Particular importance is attributed, in this context, to purely morphological differentiation between hydatid and partial mole. Also discussed is the problem of early placental angiomatosis (chorioangiosis, chorioangiomatosis). However, its association with malformations of the placenta seems to be questionable.

Angiomatosis↗
PubMed1986

Growth and function of the placenta--with special reference to various enzymes involved in the biosynthesis of steroids in the human placenta.

To study the function of the placenta from the viewpoint of placental aging, we measured the activity of various enzymes, sulfatase, 3 beta-hydroxysteroid dehydrogenase + isomerase (3 beta-HSD) and aromatizing enzyme, which are involved in the synthesis of estrogen in the placenta, as well as placental RNA and DNA levels during gestation. Our results are as follow; Enzymes involved in estrogen synthesis in human placental villi. Sulfatase activity (n mole/flask/10 min) in each trimester was not significantly different (4.10 +/- 0.10 in the first, 3.40 +/- 0.49 in the second and 4.33 +/- 0.67 in the third). 3 beta-HSD activity (n mole/flask/10 min) in each trimester was not significantly different (2.57 +/- 0.55 in the first, 2.70 +/- 0.30 in the second and 2.90 +/- 0.53 in the third). Aromatizing enzyme activity (n mole/flask/30 min) in cytosome fraction in each trimester was not significantly different (1.80 +/- 0.28 in the first, 1.60 +/- 0.28 in the second and 2.40 +/- 0.28 in the third). However, in the total homogenate, it was significantly higher in the third trimester (6.27 +/- 0.25) than in the first (3.83 +/- 0.85) or second (3.40 +/- 0.14). RNA and DNA concentrations in human placental villi. The RNA concentration (mg/g tissue) in each trimester was insignificantly different (2.48 +/- 0.20 in the first, 2.57 +/- 0.58 in the second and 2.63 +/- 0.42 in the third). However, the DNA concentration was significantly higher in the second (2.49 +/- 0.34) and third (2.42 +/- 0.45) trimesters than in the first (1.62 +/- 0.32).(ABSTRACT TRUNCATED AT 250 WORDS)

3-Hydroxysteroid Dehydrogenases↗