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At least 19 recordsLinked to original sources
PubMed2001

Human placenta as a 'dual' biomarker for monitoring fetal and maternal environment with special reference to potentially toxic trace elements. Part 3: toxic trace elements in placenta and placenta as a biomarker for these elements.

The human placenta as a body component is exposed to several harmful substances, depending upon the environmental conditions encountered. In the case of toxic metals, placental tissue can be regarded as a dual biomarker to assess maternal and fetal health. The average range of concentrations for toxic trace elements in placenta based on wet weight are found to be: cadmium 1-6 ng/g; total mercury 2-13 ng/g; methyl mercury 1-14 microg/g; and lead 5-60 ng/g. The placenta appears to be at least a partial barrier for Cadmium. Cadmium transport includes a broad variety of mechanisms. Once in circulation, it mainly interferes with Ca and Zn transportation. On the other hand, placenta appears to be a weaker harrier for Pb than for Cd. In the case of Hg, predominantly the organic form is absorbed and readily crosses the placenta. In fetal blood, the organic mercury content is equal or even greater than in maternal blood, raising questions on normal fetal development. Placenta as a biomarker could be taken as an alternative to repeated maternal blood sampling for assessing lead exposure in utero. Placenta samples are usually obtained at the time of parturition, a one-time event. Hence, each pregnancy has to be looked upon as an RTM (real time monitoring) process since the affected species is exposed to the placental source of pollutants only during the course of that particular pregnancy.

Adult↗
PubMed1997

Clinical risk factors for placenta previa-placenta accreta.

OBJECTIVE: Our purpose was to define the clinical risk factors associated with placenta previa-placenta accreta. STUDY DESIGN: Hospital records were reviewed of all cases of placenta accreta confirmed histologically between January 1985 and December 1994. Additionally, we reviewed the records of all women with placenta previa and all those undergoing cesarean hysterectomy during the same period. Multiple logistic regression analysis was used to identify independent clinical risk factors for placenta accreta. RESULTS: Among 155,670 deliveries, 62 (1/2510) were complicated by histologically confirmed placenta accreta. Placenta accreta occurred in 55 of 590 (9.3%) women with placenta previa and in 7 of 155,080 (1/22,154) without placenta previa (relative risk 2065, 95% confidence interval 944 to 4516, p < 0.0001). Among women with placenta previa, advanced maternal age (> or = 35 years) and previous cesarean delivery were independent risk factors for placenta accreta. Placenta accreta was present in 36 of 124 (29%) cases in which the placenta was implanted over the uterine scar and in 4 of 62 (6.5%) cases in which it was not (relative risk 4.5, 95% confidence interval 1.68 to 12.07). Among women with placenta previa, the risk of placenta accreta ranged from 2% in women < 35 years old with no previous cesarean deliveries to almost 39% in women with two or more previous cesarean deliveries and an anterior or central placenta previa. CONCLUSION: Placenta accreta occurs in approximately 1 of 2500 deliveries. Among women with placenta previa, the incidence is nearly 10%. In this high-risk group advanced maternal age and previous cesarean section are independent risk factors.

Adult↗
PubMed1999

[Ultrasonography of placenta previa at the third trimester of pregnancy: research for signs of placenta accreta/percreta and vasa previa. Prospective color and pulsed Doppler ultrasonography study of 45 cases].

OBJECTIVES: In a population of 45 placenta previa observed at third trimester of gestation we have tried to make the prenatal diagnosis of placenta percreta and vasa previa with color and pulsed Doppler ultrasonography. MATERIALS AND METHODS: We used a transabdominal sonography with full bladder and a transvaginal sonography with empty bladder. The first images obtained showed 20 placenta previa over the internal cervical os, 3 marginal and 22 low-lying placenta previa. We tried to find evidence of placenta percreta with gray-scale ultrasonography (loss of normal hypoechoic retroplacental myometrial zone, focal disruption of the uterine serosa and surrounding tissues, presence of intra placental lacunae) and with color and pulsed Doppler (arterial vessels with a diastolic flow value less than the flow value of a spiral artery behind the placenta, arterial vessels crossing from the placenta to surrounding tissues, intraplacental lacunae with arterial flow). We tried to find evidence of vasa previa in color and pulsed Doppler (a fetal vessel in seen above the lower segment of the uterus and below the fetal head. There is no change in the location of the vessel despite positional changes in both mother and fetus). The positivity of one sign in gray-scale ultrasonography or in color and pulsed Doppler led us to believe that the patient was affected by the anomaly. The final diagnosis of abnormal adherence of the placenta and of vasa previa was made on histological examination. RESULTS: Among the 20 placenta previa over the internal cervical os, we found 1 placenta percreta, 1 placenta accreta and 3 cases of vasa previa. In spite of our limited sample of cases of abnormal adherences, our results showed that gray-scale ultrasonography was sufficient to make a prenatal diagnosis of placenta accreta/percreta. Negative predictive value is 100% on a sample of 43 patients with no abnormal placental adherence. Color and pulsed Doppler brought no further evidence. In our population, color and pulsed Doppler had 100% positive predictive value for diagnosis of vasa previa. CONCLUSION: We found the only 2 cases of abnormal adherent placental fragments and the 3 cases of vasa previa present in our population. The study of the lower segment of the uterus should be thorough as abnormal zones may be small-sized. Color Doppler is the reference technique for sighting vasa previa and gray-scale ultrasonography for abnormal adherences of the placenta.

Female↗
PubMed1998

Risk factors and morbidity in patients with placenta previa accreta compared to placenta previa non-accreta.

BACKGROUND: Placenta accreta is associated with high morbidity and most cases occur with placenta previa. This study was carried out in an attempt to define risk factors for placenta accreta in cases of placenta previa and to quantify the increased morbidity of placenta previa accreta in comparison to placenta previa alone. METHODS: The records of all patients delivered by cesarean section (CS) for placenta previa and accreta during the seven-year period from 1990 to 1996, inclusive, were reviewed. Data regarding the demographic features, previous CS, the incidence of hysterectomy and postpartum morbidity were analyzed. RESULTS: Out of 23070 deliveries 110 (0.48%) had placenta previa, twelve (0.05%) of whom had placenta previa accreta. There was no significant difference in age and parity. Patients with a history of previous CS showed a significant increase in the incidence of placenta previa accreta (p=0.001). The percentage of accreta increased linearly from 4.1% in patients with no CS to 60% in patients who had had three or more CS. Postpartum hemorrhage and emergency hysterectomy were significantly higher among the previa accreta patients compared with the previa patients alone (p<0.001; p<0.001, respectively). CONCLUSION: In the presence of a previous history of CS, patients with antepartum diagnosis of placenta previa are considered to be at a greater risk for having placenta accreta. The risk increases with the increase in the number of previous CS. Patients with placenta previa accreta have a significantly higher incidence of PPH and are more likely to undergo emergency hysterectomy.

Adolescent↗
PubMedDate not supplied

The potential of collagenase as a new therapy for separation of human retained placenta: hydrolytic potency on human, equine and bovine placentae.

The purpose of this study was to determine to what degree bacterial collagenase may digest human placentae compared to equine and bovine placentae. Placenta samples from human, equine and bovine were incubated with bacterial collagenase solution at various concentrations. The degree of hydrolysis and collagen breakdown was measured by the release of total proteins and hydroxyproline into the incubation media. Also, whole placentae were injected via umbilical cord arteries with collagenase solution (200 U/ml, 200 ml total volume in human and 1000 ml in equine) and hydrolysis determined chemically and subjectively. Human and equine placental collagens were the most sensitive to collagenase digestion. Overall mean collagenase activity determined by the release of hydroxyproline from human placenta was 1.6 times and in equine placenta three times greater than in bovine placenta, while the breakdown of non-collagenous proteins remained negligible. When injected into whole placenta, the collagenase digested placentae evenly within 6-12 h. At 24 h, placentae were liquefied, although, umbilical blood vessels resisted collagenase digestion. Bacterial collagenase was highly effective in breaking down human placenta collagen. Intraplacental injections of collagenase via umbilical cord arteries may help to detach retained placenta in women as it does in mares and cows.

Animals↗
PubMed2002

Reproductive performance of Friesian mares after retained placenta and manual removal of the placenta.

Because the incidence of retained placenta in Friesian mares is estimated to be high, and no reports have been published on the reproductive performance of Friesian mares after retained placenta, we studied postpartum reproductive performance in Friesian brood mares with (n = 54) and without (n = 50) retained placenta. We defined a retained placenta as the failure to expel all fetal membranes within 3 h after the delivery of a foal. We subdivided the group of mares with retained placenta into mares in which the placenta had been removed manually (n = 30) and mares in which it had not (n = 24). Within each group, we compared reproductive performance after breeding in the foal heat and breeding in a subsequent heat. We also recorded the age of the mares, number of mares treated with antibiotics after insemination, and number of mares treated with prostaglandins. The interval between delivery and conception, efficacy rate (number of served cycles divided by the number of mares that had a positive pregnancy diagnosis), seasonal pregnancy rate, pregnancy rate after first insemination, pregnancy loss rate, and foaling rate did not differ between mares with and without retained placenta or between mares with and without manual removal of the retained placenta. Within each group, the pregnancy rate after first insemination did not differ between breeding for the first time in the foal heat and breeding for the first time in a subsequent heat. We concluded that reproductive performance did not differ between (1) Friesian mares with and without retained placenta and (2) Friesian mares with and without manual removal of the placenta. With regard to reproductive performance, retained placenta and manual removal of the placenta are not valid reasons to avoid foal heat breeding in Friesian mares.

Animals↗
PubMed2000

Interventions for suspected placenta praevia.

BACKGROUND: Because placenta praevia is implanted unusually low in the uterus, it may cause major, and/or repeated, antepartum haemorrhage. The traditional policy of care of women with symptomatic placenta praevia includes prolonged stay in hospital and delivery by caesarean section. OBJECTIVES: To assess the impact of any clinical intervention applied specifically because of a perceived likelihood that a pregnant woman might have placenta praevia. SEARCH STRATEGY: A comprehensive electronic search was performed to identify relevant literature. Searched databases included the Trials Register maintained by the Cochrane Pregnancy and Childbirth Group, and the Cochrane Controlled Clinical Trials Register. SELECTION CRITERIA: Any controlled clinical trial that has assessed the impact of an intervention in women diagnosed as having, or being likely to have, placenta praevia. DATA COLLECTION AND ANALYSIS: Data were extracted from the three identified trial reports, unblinded, by the author without consideration of results. MAIN RESULTS: Two comparisons could be made - home versus hospitalisation and cervical cerclage versus no cerclage. Both were associated with reduced lengths of stay in hospital antenatally. Otherwise, there was little evidence of any clear advantage or disadvantage to a policy of home versus hospital care. Cervical cerclage may reduce the risk of delivery before 34 weeks, or the birth of a baby weighing less than 2 kg or having a low 5 minute Apgar score. In general, these possible benefits were more evident in the trial of lesser methodological quality. REVIEWER'S CONCLUSIONS: There are insufficient data from trials to recommend any change in clinical practice. Available data should, however, should encourage further work to address the safety of more conservative policies of hospitalisation for women with suspected placenta praevia, and the possible value of insertion of a cervical suture.

Female↗
PubMed2000

[Placenta accreta with placenta previa after previous cesarean sections--a growing danger in modern obstetrics].

The increased rate of cesarean sections in recent decades has brought with it an increase in the frequency of placenta accreta. There are direct correlations between previous cesarean deliveries and also maternal age, with the risk of placenta accreta. There is also a direct correlation between placenta accreta and placenta previa. The risk of placenta accreta in women who have had placenta previa is 2% for those younger than 35 years and with no history of uterine surgery. The risk increases to 39% for those over 35 who have had 2 or more cesarean sections. We present 3 cases of placenta accreta admitted in 15 months, all of whom had a history of cesarean sections. The frequency of placenta accreta in our hospital is 1:1,579 deliveries, in line with the 1:1,420 in the literature. We consider hysterectomy the treatment of choice for this serious complication. When performing a cesarean in cases of placenta previa with a history of cesarean sections, the possibility of placenta accreta should be considered.

Adult↗
PubMed1999

MRI appearance of placenta percreta and placenta accreta.

The purpose of this paper is to describe the magnetic resonance imaging (MR) features of placenta accreta and percreta. We retrospectively reviewed MRI findings in four cases of placenta accreta/percreta to determine features which assist in identifying the presence and extent of placental implantation abnormality. All patients had ultrasound (US) examinations. Pathologic correlation was available in all cases. There were two cases of placenta percreta and two cases of placenta accreta. All cases were treated by hysterectomy. In the two cases of placenta percreta, the placenta demonstrated transmural extension through the uterus (percreta) on MRI. In the two cases of placenta accreta, the location of thinning in the uterine wall correlated with the location of placental invagination into the myometrium at pathology. US correlation was available in all four cases. Gray scale US did not demonstrate placental invasion in any of the four cases of placenta accreta/percreta, however, in two of three cases in which color Doppler was performed, there was flow at the uterine margin suspicious for implantation abnormality. In conclusion, MRI is useful for identifying the presence and extent of placenta accreta/percreta.

Adult↗
PubMed1999

PGE2 induces its own secretion in vitro by bovine 270-day placenta but not by 200-day placenta.

Two separate experiments were conducted to determine whether prostaglandin (PG) E2 stimulates the secretion of progesterone by 270- or 200-day Brahman placentas in vitro. Secretion of progesterone, PGF2alpha, pregnancy specific protein B, or estradiol-17beta by 270-day Brahman placentas was not affected (p > or = 0.05) by PGE2, during the 4-h incubation period at the doses tested. Indomethacin or meclofenamic acid decreased (p < or = 0.05) 270-day Brahman placental secretion of PGE and PGF2alpha by 98 and 60%, respectively. However, PGE2 induced (p < or = 0.05) its own secretion, but not the secretion of PGF2alpha (p > or = 0.05), by 270-day Brahman placentas, even in the presence of indomethacin or meclofenamic acid at a dose of 100 ng/mL. Also, secretion of 8-Epi-PGE2 by Day 270 Brahman placentas was increased (p < or = 0.05) by PGE2. Secretion of progesterone, estradiol-17beta, or pregnancy specific protein B by 200-day Brahman placentas was not affected by PGE2, 8-Epi-PGE2, PGF2alpha, estradiol-17beta, or trichosanthin during the 4- or 8-h incubation period (p > or = 0.05). Secretion of estradiol-17beta at 8 h was lower (p < or = 0.05) in all treatment groups and did not differ (p > or = 0.05) among the 8-h incubation treatment groups. Secretion of PGE by 200-day Brahman placentas was reduced (p < 0.05) by indomethacin 72 and 82% and by meclofenamic acid 72 and 96%, respectively, at 4 and 8 h when compared to controls. Secretion of PGF2alpha was reduced (p < or = 0.05) 71 and 86% by indomethacin or 89 and 89% by meclofenamic acid at 4 and 8 h, respectively, and did not differ (p > or = 0.05) between 4 and 8 h of incubation. PGE2 did not (p > or = 0.05) induce secretion of PGE above what was added in any treatment group. PGE in culture media was increased (p < or = 0.05) by 8-Epi-PGE2, pregnancy specific protein B, and the 100 ng/mL PGF2alpha dose (p < or = 0.05), but not by PGE2, progesterone, estradiol-17beta, 8-Epi-PGF2alpha, or trichosanthin. Secretion of PGF2alpha by 200-day Brahman placentas was not affected (p > or = 0.05) by 8-Epi-PGE2, progesterone, or estradiol-17beta, but PGF2alpha secretion was increased (p < or = 0.05) by trichosanthin or PGE2, even in the presence of indomethacin or meclofenamic acid. It is concluded that PGE does not affect secretion of progesterone by 200- or 270-day bovine placentas, but, pregnancy specific protein B may regulate placental secretion of PGE. Also, indomethacin and meclofenamic may affect enzymes converting PGH to PGE rather than acting only on cyclooxygenase because indomethacin and meclofenamic acid lowered PGE secretion by 270-day Brahman placentas more than they lowered PGF2alpha. In addition, it is concluded that PGE2 can induce bovine placental secretion of PGE, but this is dependent upon the stage of gestation.

Abortifacient Agents, Nonsteroidal↗
PubMed2000

Hyperexpression of ICAM-1 and CD36 in placentas infected with Plasmodium falciparum: a possible role of these molecules in sequestration of infected red blood cells in placentas.

AIMS: During pregnancy, Plasmodium falciparum malaria is frequent and associated with maternofetal complications. This could be the consequence of sequestration by several adhesion molecules of parasite-infected red blood cells in syncytiotrophoblast. To investigate the expression of ICAM-1 and CD36, two of the adhesion molecules for Plasmodium falciparum, an immunohistochemical study was carried out in malaria-infected placentas. METHODS AND RESULTS: Thirty-five infected and 35 noninfected samples were chosen randomly. According to the histological classification of Bulmer, the infected placentas were separated in three groups: active, active chronic and past-chronic infection. CD36 was localized in the cytoplasm of stromal cells of terminal villi of infected or noninfected placentas, but not in syncytiotrophoblast. ICAM-1 was detected in the cytoplasm of stromal and endothelial villous cells in both infected and noninfected placentas and in syncytiotrophoblast of eight infected placentas showing more frequently active than active chronic or past-chronic infection (P < 0.001). The percentage of cells immunostained for CD36 or ICAM-1 was evaluated in the terminal villi. The proportion of villous cells, with ICAM-1 and CD36 immunostaining, was significantly higher in infected vs. noninfected placentas (P < 0.0001) and CD36 was detected more in acute inflammatory vs. past-chronic inflammatory placentas (P < 0.05). CONCLUSIONS: The higher expression of ICAM-1 in infected placentas and its localization in syncytiotrophoblast particularly during acute infection, suggest ICAM-1 can act directly in the sequestration of parasite-infected red blood cells (IRBCs). On the other hand, the expression of CD36 is influenced by the presence of IRBCs without being directly implicated in sequestration of IRBCs. The hyperexpression of these two molecules could explain the high frequency of malaria during pregnancy.

Adult↗