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Sample records for placental oxygen transfer

  1. Evolution of factors affecting placental oxygen transfer

    DEFF Research Database (Denmark)

    Carter, A M

    2009-01-01

    states, are more amenable to analysis. This is exemplified by factors contributing, respectively, to blood oxygen affinity and placental diffusing capacity. Comparative genomics has given fresh insight into the evolution of the beta-globin gene complex. In higher primates, duplication of an embryonic...

  2. Image-Based Modeling of Blood Flow and Oxygen Transfer in Feto-Placental Capillaries

    Science.gov (United States)

    Brownbill, Paul; Janáček, Jiří; Jirkovská, Marie; Kubínová, Lucie; Chernyavsky, Igor L.; Jensen, Oliver E.

    2016-01-01

    During pregnancy, oxygen diffuses from maternal to fetal blood through villous trees in the placenta. In this paper, we simulate blood flow and oxygen transfer in feto-placental capillaries by converting three-dimensional representations of villous and capillary surfaces, reconstructed from confocal laser scanning microscopy, to finite-element meshes, and calculating values of vascular flow resistance and total oxygen transfer. The relationship between the total oxygen transfer rate and the pressure drop through the capillary is shown to be captured across a wide range of pressure drops by physical scaling laws and an upper bound on the oxygen transfer rate. A regression equation is introduced that can be used to estimate the oxygen transfer in a capillary using the vascular resistance. Two techniques for quantifying the effects of statistical variability, experimental uncertainty and pathological placental structure on the calculated properties are then introduced. First, scaling arguments are used to quantify the sensitivity of the model to uncertainties in the geometry and the parameters. Second, the effects of localized dilations in fetal capillaries are investigated using an idealized axisymmetric model, to quantify the possible effect of pathological placental structure on oxygen transfer. The model predicts how, for a fixed pressure drop through a capillary, oxygen transfer is maximized by an optimal width of the dilation. The results could explain the prevalence of fetal hypoxia in cases of delayed villous maturation, a pathology characterized by a lack of the vasculo-syncytial membranes often seen in conjunction with localized capillary dilations. PMID:27788214

  3. Image-based modeling of blood flow and oxygen transfer in feto-placental capillaries

    Science.gov (United States)

    Pearce, Philip; Jensen, Oliver

    2016-11-01

    During pregnancy, oxygen diffuses from maternal to fetal blood through the placenta. At the smallest scale of the feto-placental vasculature are the "terminal villi", bulbous structures that are thought to be the main sites for oxygen transfer in the final trimester of pregnancy. The objective of this study is to investigate blood flow and oxygen transfer in the terminal villi of the placenta. Three-dimensional representations of villous and capillary surfaces, obtained from confocal laser scanning microscopy, are converted to finite-element meshes. Simulations of blood flow and oxygen transfer are performed to calculate the vascular flow resistance of the capillaries and the total oxygen transfer rate from the maternal blood. Scaling arguments, which predict the oxygen transfer across a range of Peclet numbers, are shown to be an efficient tool for quantifying the effect of statistical variability and experimental uncertainty. The effect of commonly observed localised dilations in the fetal vasculature on oxygen transfer is quantified using an idealised model in a simplified geometry. The model predicts how, for a fixed pressure drop through a capillary, oxygen transfer is maximised by an optimal shape of the dilation, leading to an increase in oxygen transfer of up to 15%.

  4. Transferência placentária de drogas Placental drug transfer

    Directory of Open Access Journals (Sweden)

    Ricardo de Carvalho Cavalli

    2006-09-01

    Full Text Available Grávidas podem depender do uso de medicações para minimizar os agravos da doença preexistente. A gravidez, por si só, pode causar situações que comprometem o bem-estar materno, como náuseas e vômitos, as quais necessitam de tratamento. O obstetra deve estar atento à transferência placentária de drogas e à exposição do feto a agentes teratogênicos ou tóxicos, que podem comprometer o seu desenvolvimento ou mesmo sua vida futura.O transporte através da placenta envolve o movimento de moléculas entre três compartimentos: sangue materno, citoplasma do sinciciotrofoblasto e sangue fetal. Esse movimento pode ocorrer pelos seguintes mecanismos: difusão simples, difusão facilitada, transporte ativo, bombas classe P, V, F e grande família ABC e endocitose. Com o uso de anticonvulsivantes a incidência de malformações maiores em recém-nascidos expostos é de 4 a 6%, comparado com 2 a 4% na população geral. A politerapia é mais lesiva, especialmente se o ácido valpróico e a hidantoína fazem parte da associação. Para as pacientes epilépticas clinicamente assintomáticas há dois anos recomenda-se a suspensão da drogas em uso, porém se apresentam crises, torna-se prudente consultar neurologista para discussão da terapia anticonvulsivante com melhores benefícios e menores efeitos colaterais. Os anestésicos locais e os opióides são largamente utilizados durante a resolução da gestação. A lidocaína utilizada como anestésico por via perineal para episiotomia, na dose fixa de 400 mg, apresenta alta concentração plasmática materna e alta taxa de transferência placentária no momento do nascimento, que vem alertar para o cuidado no uso de doses repetidas. A bupivacaína administrada por via epidural representa anestésico seguro, apresentando-se na forma racêmica e com transferência placentária em torno de 30%. A fentanila, anestésico opióide, utilizado por via epidural na resolução por cesariana, na dose

  5. Important aspects of placental-specific gene transfer.

    Science.gov (United States)

    Kaufman, Melissa R; Albers, Renee E; Keoni, Chanel; Kulkarni-Datar, Kashmira; Natale, David R; Brown, Thomas L

    2014-10-15

    The placenta is a unique and highly complex organ that develops only during pregnancy and is essential for growth and survival of the developing fetus. The placenta provides the vital exchange of gases and wastes, the necessary nutrients for fetal development, acts as immune barrier that protects against maternal rejection, and produces numerous hormones and growth factors that promote fetal maturity to regulate pregnancy until parturition. Abnormal placental development is a major underlying cause of pregnancy-associated disorders that often result in preterm birth. Defects in placental stem cell propagation, growth, and differentiation are the major factors that affect embryonic and fetal well-being and dramatically increase the risk of pregnancy complications. Understanding the processes that regulate placentation is important in determining the underlying factors behind abnormal placental development. The ability to manipulate genes in a placenta-specific manner provides a unique tool to analyze development and eliminates potentially confounding results that can occur with traditional gene knockouts. Trophoblast stem cells and mouse embryos are not overly amenable to traditional gene transfer techniques. Most viral vectors, however, have a low infection rate and often lead to mosaic transgenesis. Although the traditional method of embryo transfer is intrauterine surgical implantation, the methodology reported here, combining lentiviral blastocyst infection and nonsurgical embryo transfer, leads to highly efficient and placental-specific gene transfer. Numerous advantages of our optimized procedures include increased investigator safety, a reduction in animal stress, rapid and noninvasive embryo transfer, and higher a rate of pregnancy and live birth.

  6. Transferência placentária de drogas Placental drug transfer

    OpenAIRE

    Ricardo de Carvalho Cavalli; Cláudia de Oliveira Baraldi; Sérgio Pereira da Cunha

    2006-01-01

    Grávidas podem depender do uso de medicações para minimizar os agravos da doença preexistente. A gravidez, por si só, pode causar situações que comprometem o bem-estar materno, como náuseas e vômitos, as quais necessitam de tratamento. O obstetra deve estar atento à transferência placentária de drogas e à exposição do feto a agentes teratogênicos ou tóxicos, que podem comprometer o seu desenvolvimento ou mesmo sua vida futura.O transporte através da placenta envolve o movimento de moléculas e...

  7. Factors affecting the placental transfer of actinides

    Energy Technology Data Exchange (ETDEWEB)

    Sikov, M.R.; Kelman, B.J. (Pacific Northwest Laboratory, Richland, WA (USA))

    1989-01-01

    The primary goal of this paper is to consider factors that affect the availability and transport of actinides from maternal blood, through the placenta, to the conceptus. These factors, of particular importance in scaling results from animals to man, include the route and temporal pattern of administration, the mass and physicochemical state of material administered, metabolism of the pregnant animal and fetal organs or tissue, and species-specific changes in placental structure relative to stage of gestation at exposure. Preliminary concepts for descriptive and kinetic models are proposed to integrate these results, to identify additional information required for developing more comprehensive models, and to provide a basis for scaling to human pregnancies for purposes of radiation dosimetry.

  8. Placental oxygen transport estimated by the hyperoxic placental BOLD MRI response

    DEFF Research Database (Denmark)

    Sørensen, Anne Nødgaard; Sinding, Marianne; Peters, David A;

    2015-01-01

    cases of severe early onset FGR, placental BOLD MRI was performed in a 1.5 Tesla MRI system (TR:8000 msec, TE:50 msec, Flip angle:90). Placental histological examination was performed in the FGR cases. In normal pregnancies, the average hyperoxic placental BOLD response was 12.6 ± 5.4% (mean ± SD...

  9. Bidirectional Transfer Study of Polystyrene Nanoparticles across the Placental Barrier in an ex Vivo Human Placental Perfusion Model

    Science.gov (United States)

    Grafmueller, Stefanie; Manser, Pius; Diener, Liliane; Diener, Pierre-André; Maeder-Althaus, Xenia; Maurizi, Lionel; Jochum, Wolfram; Krug, Harald F.; Buerki-Thurnherr, Tina; von Mandach, Ursula

    2015-01-01

    Background Nanoparticle exposure in utero might not be a major concern yet, but it could become more important with the increasing application of nanomaterials in consumer and medical products. Several epidemiologic and in vitro studies have shown that nanoparticles can have potential toxic effects. However, nanoparticles also offer the opportunity to develop new therapeutic strategies to treat specifically either the pregnant mother or the fetus. Previous studies mainly addressed whether nanoparticles are able to cross the placental barrier. However, the transport mechanisms underlying nanoparticle translocation across the placenta are still unknown. Objectives In this study we examined which transport mechanisms underlie the placental transfer of nanoparticles. Methods We used the ex vivo human placental perfusion model to analyze the bidirectional transfer of plain and carboxylate modified polystyrene particles in a size range between 50 and 300 nm. Results We observed that the transport of polystyrene particles in the fetal to maternal direction was significantly higher than for the maternal to fetal direction. Regardless of their ability to cross the placental barrier and the direction of perfusion, all polystyrene particles accumulated in the syncytiotrophoblast of the placental tissue. Conclusions Our results indicate that the syncytiotrophoblast is the key player in regulating nanoparticle transport across the human placenta. The main mechanism underlying this translocation is not based on passive diffusion, but is likely to involve an active, energy-dependent transport pathway. These findings will be important for reproductive toxicology as well as for pharmaceutical engineering of new drug carriers. Citation Grafmueller S, Manser P, Diener L, Diener PA, Maeder-Althaus X, Maurizi L, Jochum W, Krug HF, Buerki-Thurnherr T, von Mandach U, Wick P. 2015. Bidirectional transfer study of polystyrene nanoparticles across the placental barrier in an ex vivo human

  10. Adenoviral-mediated placental gene transfer of IGF-1 corrects placental insufficiency via enhanced placental glucose transport mechanisms.

    Directory of Open Access Journals (Sweden)

    Helen N Jones

    Full Text Available Previous work in our laboratory demonstrated that over-expression of human insulin-like growth factor -1 (hIGF-1 in the placenta corrects fetal weight deficits in mouse, rat, and rabbit models of intrauterine growth restriction without changes in placental weight. The underlying mechanisms of this effect have not been elucidated. To investigate the effect of intra-placental IGF-1 over-expression on placental function we examined glucose transporter expression and localization in both a mouse model of IUGR and a model of human trophoblast, the BeWo Choriocarcinoma cell line.At gestational day 18, animals were divided into four groups; sham-operated controls, uterine artery branch ligation (UABL, UABL+Ad-hIGF-1 (10(8 PFU, UABL+Ad-LacZ (10(8 PFU. At gestational day 20, pups and placentas were harvested by C-section. For human studies, BeWo choriocarcinoma cells were grown in F12 complete medium +10%FBS. Cells were incubated in serum-free control media ± Ad-IGF-1 or Ad-LacZ for 48 hours. MOIs of 10∶1 and 100∶1 were utilized. The RNA, protein expression and localization of glucose transporters GLUT1, 3, 8, and 9 were analyzed by RT-PCR, Western blot and immunohistochemistry.In both the mouse placenta and BeWo, GLUT1 regulation was linked to altered protein localization. GLUT3, localized to the mouse fetal endothelial cells, was reduced in placental insufficiency but maintained with Ad-I GF-1 treatment. Interestingly, GLUT8 expression was reduced in the UABL placenta but up-regulated following Ad-IGF-1 in both mouse and human systems. GLUT9 expression in the mouse was increased by Ad-IGF-1 but this was not reflected in the BeWo, where Ad-IGF-1 caused moderate membrane relocalization.Enhanced GLUT isoform transporter expression and relocalization to the membrane may be an important mechanism in Ad-hIGF-1mediated correction of placental insufficiency.

  11. Real-Time Monitoring of Placental Oxygenation during Maternal Hypoxia and Hyperoxygenation Using Photoacoustic Imaging

    Science.gov (United States)

    Arthuis, Chloé J.; Novell, Anthony; Raes, Florian; Escoffre, Jean-Michel; Lerondel, Stéphanie; Le Pape, Alain; Bouakaz, Ayache; Perrotin, Franck

    2017-01-01

    Purpose This preclinical study aimed to evaluate placental oxygenation in pregnant rats by real-time photoacoustic (PA) imaging on different days of gestation and to specify variations in placental oxygen saturation under conditions of maternal hypoxia and hyperoxygenation. Material and methods Placentas of fifteen Sprague-Dawley rats were examined on days 14, 17, and 20 of pregnancy with a PA imaging system coupled to high-resolution ultrasound imaging. Pregnant rats were successively exposed to hyperoxygenated and hypoxic conditions by changing the oxygen concentration in inhaled gas. Tissue oxygen saturation was quantitatively analyzed by real-time PA imaging in the skin and 3 regions of the placenta. All procedures were performed in accordance with applicable ethical guidelines and approved by the animal care committee. Results Maternal hypoxia was associated with significantly greater decrease in blood oxygen saturation (ΔO2 Saturation) in the skin (70.74% ±7.65) than in the mesometrial triangle (32.66% ±5.75) or other placental areas (labyrinth: 18.58% ± 6.61; basal zone: 13.13% ±5.72) on different days of pregnancy (P<0.001). ΔO2 Saturation did not differ significantly between the labyrinth, the basal zone, and the decidua. After the period of hypoxia, maternal hyperoxygenation led to a significant rise in oxygen saturation, which returned to its initial values in the different placental regions (P<0.001). Conclusions PA imaging enables the variation of blood oxygen saturation to be monitored in the placenta during maternal hypoxia or hyperoxygenation. This first preclinical study suggests that the placenta plays an important role in protecting the fetus against maternal hypoxia. PMID:28081216

  12. Somatic cell nuclear transfer in the sheep induces placental defects that likely precede fetal demise.

    Science.gov (United States)

    Fletcher, C J; Roberts, C T; Hartwich, K M; Walker, S K; McMillen, I C

    2007-01-01

    The efficiency of cloning by somatic cell nuclear transfer (SCNT) is poor in livestock with approximately 5% of transferred cloned embryos developing to term. SCNT is associated with gross placental structural abnormalities. We aimed to identify defects in placental histology and gene expression in failing ovine cloned pregnancies to better understand why so many clones generated by SCNT die in utero. Placentomes from SCNT pregnancies (n = 9) and age matched, naturally mated controls (n = 20) were collected at two gestational age ranges (105-134 days and 135-154 days; term = 147 days). There was no effect of cloning on total placental weight. However, cloning reduced the number of placentomes at both gestational ages (105-134 days: control 55.0 +/- 4.2, clone 44.7 +/- 8.0 and 135-154 days: control 72.2 +/- 5.1, clone 36.6 +/- 5.1; P clone 18.6 +/- 2.8 g and 135-154 days: control 6.6 +/- 0.6 g, clone 7.0 +/- 2.0 g; P cloned pregnancies had a significant volume of shed trophoblast and fetal villous hemorrhage, absent in controls, at both gestational age ranges (P clones. In addition, cloning reduced placental expression of key genes in placental differentiation and function. Thus, cloning by SCNT results in both gross and microscopic placental abnormalities. We speculate that trophoblast apoptosis, shedding, and hemorrhage may be causal in fetal death in ovine clones.

  13. Placental transfer of enfuvirtide in the ex vivo human placenta perfusion model.

    Science.gov (United States)

    Ceccaldi, Pierre-Francois; Ferreira, Claudia; Gavard, Laurent; Gil, Sophie; Peytavin, Gilles; Mandelbrot, Laurent

    2008-04-01

    The objective of the study was to determine the placental transfer of the antiretroviral fusion inhibitor, enfuvirtide (Fuzeon). Human cotyledons were perfused for 90 minutes in an open dual circuit with enfuvirtide, and fetal venous samples were collected every 5 minutes. Three perfusion experiments were validated using antipyrine. Enfuvirtide was not detected in the fetal compartment in any of the 3 experiments. The mean concentration of the drug measured in the maternal compartment was 12,400 ng/mL (range, 6500-16,200 ng/mL), which is 2.5 times the maximum concentration recommended for patients treated with enfuvirtide. Even at maternal concentrations twice above therapeutic levels, no placental transfer of enfuvirtide was observed. The high molecular weight of the molecule (4492 kDa) and its ionized state may account for the lack of placental transfer. This result suggests that enfuvirtide could be used in HIV-infected pregnant women without causing fetal exposure.

  14. Placental Gas Exchange and the Oxygen Supply to the Fetus

    DEFF Research Database (Denmark)

    Carter, Anthony M

    2015-01-01

    of these several factors as well as responses to acute or sustained hypoxia has been explored in the sheep model. In addition, much has been learned in the context of hypobaric hypoxia by studying human populations that have resided at high altitude for varying periods of time. Embryonic development occurs under...... anaerobic conditions and even the fetus is adapted to a low oxygen environment. Nevertheless, there is a reserve capacity, and during acute hypoxia the fetus can counter a 50% reduction in oxygen delivery by increasing fractional extraction. During sustained hypoxia, on the other hand, fetal growth...

  15. Placental transfer of radiopharmaceuticals and dosimetry in pregnancy

    Energy Technology Data Exchange (ETDEWEB)

    Russell, J.R. [Univ. of Maryland, Baltimore, MD (United States); Stabin, M.G.; Sparks, R.B. [Oak Ridge Inst. for Science and Education, TN (United States)

    1999-01-01

    The calculation of radiation dose estimates to the fetus is often important in nuclear medicine. To obtain the best estimates of radiation dose to the fetus, the best biological and physical models should be employed. In this paper, after identification of radiopharmaceuticals often administered to women of childbearing age, the most recent data available on the placental crossover of these radiopharmaceuticals was used (with standard kinetic models describing the maternal distribution and retention and with the best available physical models) to obtain fetal dose estimates for these radiopharmaceuticals were identified as those most commonly administered to women of childbearing years. The literature yielded information on placental crossover of 15 radiopharmaceuticals, from animal or human data. Radiation dose estimates are presented in early pregnancy and at 3-, 6-, and 9-months gestation for these radiopharmaceuticals, as well as for many others used in nuclear medicine (the latter considering only maternal organ contributions to fetal dose). 46 refs., 1 fig., 5 tabs.

  16. The impact of cocaine and heroin on the placental transfer of methadone

    Directory of Open Access Journals (Sweden)

    Wenzinger Silvana

    2009-06-01

    Full Text Available Abstract Background Methadone is the therapeutic agent of choice for the treatment of opiate addiction in pregnancy. The co-consumption (heroin, cocaine which may influence the effects of methadone is frequent. Therefore, the impact of cocaine and heroin on the placental transfer of methadone and the placental tissue was investigated under in vitro conditions. Methods Placentae (n = 24 were ex-vivo perfused with medium (m (control, n = 6, m plus methadone (n = 6, m plus methadone and cocaine (n = 6 or m plus methadone and heroin (n = 6. Placental functionality parameters like antipyrine permeability, glucose consumption, lactate production, hormone production (hCG and leptin, microparticles release and the expression of P-glycoprotein were analysed. Results Methadone accumulated in placental tissue. Methadone alone decreased the transfer of antipyrine from 0.60 +/- 0.07 to 0.50 +/- 0.06 (fetal/maternal ratio, mean +/- SD, P Conclusion The combination of cocaine or heroin with methadone increase antipyrine permeability. Changes of MPs resemble findings seen in oxidative stress of syncytiotrophoblast.

  17. Placental transfer and fetal metabolic effects of phenylephrine and ephedrine during spinal anesthesia for cesarean delivery.

    Science.gov (United States)

    Ngan Kee, Warwick D; Khaw, Kim S; Tan, Perpetua E; Ng, Floria F; Karmakar, Manoj K

    2009-09-01

    Use of ephedrine in obstetric patients is associated with depression of fetal acid-base status. The authors hypothesized that the mechanism underlying this is transfer of ephedrine across the placenta and stimulation of metabolism in the fetus. A total of 104 women having elective Cesarean delivery under spinal anesthesia randomly received infusion of phenylephrine (100 microg/ml) or ephedrine (8 mg/ml) titrated to maintain systolic blood pressure near baseline. At delivery, maternal arterial, umbilical arterial, and umbilical venous blood samples were taken for measurement of blood gases and plasma concentrations of phenylephrine, ephedrine, lactate, glucose, epinephrine, and norepinephrine. In the ephedrine group, umbilical arterial and umbilical venous pH and base excess were lower, whereas umbilical arterial and umbilical venous plasma concentrations of lactate, glucose, epinephrine, and norepinephrine were greater. Umbilical arterial Pco2 and umbilical venous Po2 were greater in the ephedrine group. Placental transfer was greater for ephedrine (median umbilical venous/maternal arterial plasma concentration ratio 1.13 vs. 0.17). The umbilical arterial/umbilical venous plasma concentration ratio was greater for ephedrine (median 0.83 vs. 0.71). Ephedrine crosses the placenta to a greater extent and undergoes less early metabolism and/or redistribution in the fetus compared with phenylephrine. The associated increased fetal concentrations of lactate, glucose, and catecholamines support the hypothesis that depression of fetal pH and base excess with ephedrine is related to metabolic effects secondary to stimulation of fetal beta-adrenergic receptors. Despite historical evidence suggesting uteroplacental blood flow may be better maintained with ephedrine, the overall effect of the vasopressors on fetal oxygen supply and demand balance may favor phenylephrine.

  18. Pregnancy Complications: Placental Abruption

    Science.gov (United States)

    ... wall of the uterus (womb) and supplies the baby with food and oxygen through the umbilical cord. Placental abruption ... wall of the uterus (womb) and supplies the baby with food and oxygen through the umbilical cord. Placental abruption ...

  19. The Role of Secretory Autophagy in Zika Virus Transfer through the Placental Barrier

    Science.gov (United States)

    Zhang, Zhong-Wei; Li, Zi-Lin; Yuan, Shu

    2017-01-01

    Recent studies indicated that the Zika virus genome could be detected in the amniotic fluid and the fetal brain, which confirms that the virus can cross the placental barrier. Secretory autophagy or exosome pathways may participate in this virus transfer. Autophagy modulators regulate autophagosome formation or membrane fusion with lysosomal vesicles and therefore inhibit viral nucleocapsid releasing or virus transfer to the fetus hypothetically. However, some autophagy modulators may enhance virus replication. Autophagy inhibitors may arrest placental development; while exaggeration of autophagy in human placenta may be associated with the fetal growth restriction. Therefore, autophagy modulators should be used carefully due to their complex clinical effects. Alternatively, exosome-specific inhibitors might be also considered, although their safety of both maternal and fetal conditions must be carefully assessed before any advancement to human clinical trials. PMID:28119857

  20. Placental transfer of rilpivirine in an ex vivo human cotyledon perfusion model.

    Science.gov (United States)

    Mandelbrot, Laurent; Duro, Dominique; Belissa, Emilie; Peytavin, Gilles

    2015-05-01

    Placental transfers of the HIV nonnucleoside reverse transcriptase inhibitor rilpivirine were investigated in 8 term human cotyledons perfused with rilpivirine (400 ng/ml) in the maternal-to-fetal direction. The mean fetal transfer rate (FTR) (fetal/maternal concentration at steady state from 15 to 90 min) was 26% ± 8% (mean ± standard deviation), and the clearance index (rilpivirine FTR/antipyrine FTR) was 61% ± 20%. This shows that rilpivirine crosses the placenta at a relatively high rate, suggesting that the fetus is exposed to the compound during treatment of the mother. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  1. Placental transfer of darunavir in an ex vivo human cotyledon perfusion model.

    Science.gov (United States)

    Mandelbrot, Laurent; Duro, Dominique; Belissa, Emilie; Peytavin, Gilles

    2014-09-01

    Placental transfer of the HIV protease inhibitor darunavir was investigated in 5 term human cotyledons perfused with darunavir (1,000 ng/ml) in the maternal to fetal direction. The mean (± the standard deviation [SD]) fetal transfer rate (FTR) (fetal/maternal concentration at steady state from 30 to 90 min) was 15.0%±2.1%, and the mean (±SD) clearance index (darunavir FTR/antipyrine FTR) was 40.3%±5.8%. This shows that darunavir crosses the placenta at a relatively low rate, resulting in fetal exposure. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  2. The impact of cocaine and heroin on the placental transfer of methadone

    Science.gov (United States)

    Malek, Antoine; Obrist, Cristina; Wenzinger, Silvana; von Mandach, Ursula

    2009-01-01

    Background Methadone is the therapeutic agent of choice for the treatment of opiate addiction in pregnancy. The co-consumption (heroin, cocaine) which may influence the effects of methadone is frequent. Therefore, the impact of cocaine and heroin on the placental transfer of methadone and the placental tissue was investigated under in vitro conditions. Methods Placentae (n = 24) were ex-vivo perfused with medium (m) (control, n = 6), m plus methadone (n = 6), m plus methadone and cocaine (n = 6) or m plus methadone and heroin (n = 6). Placental functionality parameters like antipyrine permeability, glucose consumption, lactate production, hormone production (hCG and leptin), microparticles release and the expression of P-glycoprotein were analysed. Results Methadone accumulated in placental tissue. Methadone alone decreased the transfer of antipyrine from 0.60 +/- 0.07 to 0.50 +/- 0.06 (fetal/maternal ratio, mean +/- SD, P < 0.01), whereas the combination with cocaine or heroin increased it (0.56 +/- 0.08 to 0.68 +/- 0.13, P = 0.03 and 0.58 +/- 0.21 to 0.71 +/- 0.24; P = 0.18). Microparticles (MPs) released from syncytiotrophoblast into maternal circuit increased by 30% after cocaine or heroin (P < 0.05) and the expression of P-glycoprotein in the tissue increased by ≥ 49% after any drug (P < 0.05). All other measured parameters did not show any significant effect when methadone was combined with cocaine or heroine. Conclusion The combination of cocaine or heroin with methadone increase antipyrine permeability. Changes of MPs resemble findings seen in oxidative stress of syncytiotrophoblast. PMID:19519880

  3. Oxygen transfer in human carotid artery bifurcation

    Institute of Scientific and Technical Information of China (English)

    Z.G.Zhang; Y.B.Fan; X.Y.Deng

    2007-01-01

    Arterial bifurcations are places where blood flow may be disturbed and slow recirculation flow may occur.To reveal the correlation between local oxygen transfer and atherogenesis, a finite element method was employed to simulate the blood flow and the oxygen transfer in the human carotid artery bifurcation. Under steady-state flow conditions, the numerical simulation demonstrated a variation in local oxygen transfer at the bifurcation, showing that the convective condition in the disturbed flow region may produce uneven local oxygen transfer at the blood/wall interface.The disturbed blood flow with formation of slow eddies in the carotid sinus resulted in a depression in oxygen supply to the arterial wall at the entry of the sinus, which in turn may lead to an atherogenic response of the arterial wall, and contribute to the development of atherosclerotic stenosis there.

  4. Micronucleated Erythrocytes in Newborn Rats Exposed to Raltegravir Placental Transfer

    Science.gov (United States)

    Torres-Mendoza, Blanca Miriam; Coronado-Medina, Damharis Elizabeth; Vázquez-Valls, Eduardo; Zamora-Perez, Ana Lourdes; Lemus-Varela, María de Lourdes

    2014-01-01

    The use of raltegravir in treating HIV/AIDS has been proposed due to its effectiveness in suppressing high loads of HIV RNA in pregnant women, thus preventing infection of the fetus. However, administration of raltegravir during pregnancy produces a compound which is transferred to high concentrations to the offspring. The objective of this study is to evaluate the transplacental genotoxic effect of raltegravir in newborn rats. We evaluated the number of micronucleated erythrocytes (MNE), micronucleated polychromatic erythrocytes (MNPCE), and polychromatic erythrocytes (PCE) in the peripheral blood samples of the offspring of Wistar rats treated 6 days before birth with oral administration of raltegravir. The animals were randomly assigned to five groups as follows: raltegravir at doses of 15, 30, or 60 mg/day, cyclophosphamide 10 mg/kg (positive control), or 0.5 ml of sterile water (negative control). In addition, the effect of these drugs on the weight and height of newborns was assessed. There were no differences in the number of MNE, MNPCE, and PCE, and a slight decrease in the weight and height was observed in the offspring of the rat mothers treated with raltegravir. Genotoxicity studies are required in pregnant women to determine the risk of using raltegravir to the fetuses. PMID:24977162

  5. Micronucleated Erythrocytes in Newborn Rats Exposed to Raltegravir Placental Transfer

    Directory of Open Access Journals (Sweden)

    Blanca Miriam Torres-Mendoza

    2014-01-01

    Full Text Available The use of raltegravir in treating HIV/AIDS has been proposed due to its effectiveness in suppressing high loads of HIV RNA in pregnant women, thus preventing infection of the fetus. However, administration of raltegravir during pregnancy produces a compound which is transferred to high concentrations to the offspring. The objective of this study is to evaluate the transplacental genotoxic effect of raltegravir in newborn rats. We evaluated the number of micronucleated erythrocytes (MNE, micronucleated polychromatic erythrocytes (MNPCE, and polychromatic erythrocytes (PCE in the peripheral blood samples of the offspring of Wistar rats treated 6 days before birth with oral administration of raltegravir. The animals were randomly assigned to five groups as follows: raltegravir at doses of 15, 30, or 60 mg/day, cyclophosphamide 10 mg/kg (positive control, or 0.5 ml of sterile water (negative control. In addition, the effect of these drugs on the weight and height of newborns was assessed. There were no differences in the number of MNE, MNPCE, and PCE, and a slight decrease in the weight and height was observed in the offspring of the rat mothers treated with raltegravir. Genotoxicity studies are required in pregnant women to determine the risk of using raltegravir to the fetuses.

  6. Studying placental transfer of highly purified non-dioxin-like PCBs in two models of the placental barrier

    DEFF Research Database (Denmark)

    Correia Carreira, S; Cartwright, L; Mathiesen, L

    2011-01-01

    Currently, toxicology and toxicokinetics of purified non-dioxin-like polychlorinated biphenyls (NDL-PCBs) are poorly characterised. Transplacental kinetics of NDL-PCBs can be studied in a variety of models, but careful validation of each model is crucial. We aimed to develop a standard operating...... procedure for establishing an in vitro model of the human placental barrier. Using this model, we sought to investigate placental transport kinetics of two NDL-PCB congeners. Firstly, we compared the BeWo cell line of the American Type Culture Collection with the BeWo b30 clone and determined parameters...... for monolayer formation. Secondly, we performed placental perfusions to validate the in vitro model. To that end, the transport of radiolabelled PCB52 and 180 was investigated in both models. We were not able to grow the ATCC cell line to confluency, but determined monolayer formation using BeWo b30...

  7. Epidural ropivacaine hydrochloride during labour: protein binding, placental transfer and neonatal outcome.

    LENUS (Irish Health Repository)

    Porter, J M

    2012-02-03

    This study was undertaken: (i) to quantify the effects of labour and epidural analgesia on plasma alpha1-acid glycoprotein concentration, (ii) to examine the effects of changes in plasma alpha1-acid glycoprotein concentration on plasma protein binding and placental transfer of ropivacaine, and (iii) to examine the association between umbilical venous ropivacaine concentration and neurobehavioural function in the neonate. Multiparous patients undergoing induction of labour received a continuous epidural infusion of 0.1% ropivacaine following an epidural bolus. A significant association was demonstrated between maternal plasma alpha1-acid glycoprotein concentration and 1\\/free fraction of ropivacaine 60 min after starting ropivacaine administration (r(2) = 0.77) but not at delivery. No significant correlation was demonstrable between maternal unbound ropivacaine concentration and either neonatal (cord) ropivacaine concentration or UV\\/MV (a measure of placental transfer). Thirty minutes after delivery, 9\\/10 neonates had neurological and adaptive capacity scores < 35, whereas only three infants had scores < 35 at 2 h. All scores exceeded 35 16 h after delivery. No association between mean (SD) umbilical venous ropivacaine concentration [0.09 (0.08) mg x l(-1)] and neurological and adaptive capacity scores was demonstrated.

  8. Placental transfer and fetal distribution of /sup 3/H-retinoic acid in rats

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, R.R.; Kumar, V.; Banerjee, R.; Misra, U.K.

    1986-01-01

    The placental transfer of /sup 3/H-retinoic acid in vitamin A deprived and vitamin A supplemented pregnant female rats was studied on 20th day of gestation and compared with /sup 3/H-retinyl acetate. Radiolabelled compounds were administered to pregnant mothers orally in groundnut oil six hours before sacrifice. The distribution of radioactivity of the two compounds was studied in maternal intestine, liver and plasma and fetal brain, heart liver lung and placenta. The transfer of /sup 3/H-retinoic acid across placenta was restricted as compared to that of /sup 3/H-retinyl acetate which may explain the reason why retinoic acid does not support fetal growth.

  9. High Maternal HIV-1 Viral Load During Pregnancy Is Associated With Reduced Placental Transfer of Measles IgG Antibody

    Science.gov (United States)

    Farquhar, Carey; Nduati, Ruth; Haigwood, Nancy; Sutton, William; Mbori-Ngacha, Dorothy; Richardson, Barbra; John-Stewart, Grace

    2012-01-01

    Background Studies among HIV-1–infected women have demonstrated reduced placental transfer of IgG antibodies against measles and other pathogens. As a result, infants born to women with HIV-1 infection may not acquire adequate passive immunity in utero and this could contribute to high infant morbidity and mortality in this vulnerable population. Methods To determine factors associated with decreased placental transfer of measles IgG, 55 HIV-1–infected pregnant women who were enrolled in a Nairobi perinatal HIV-1 transmission study were followed. Maternal CD4 count, HIV-1 viral load, and HIV-1–specific gp41 antibody concentrations were measured antenatally and at delivery. Measles IgG concentrations were assayed in maternal blood and infant cord blood obtained during delivery to calculate placental antibody transfer. Results Among 40 women (73%) with positive measles titers, 30 (75%) were found to have abnormally low levels of maternofetal IgG transfer (<95%). High maternal HIV-1 viral load at 32 weeks’ gestation and at delivery was associated with reductions in placental transfer (P < 0.0001 and P = 0.0056, respectively) and infant measles IgG concentrations in cord blood (P < 0.0001 and P = 0.0073, respectively). High maternal HIV-1–specific gp41 antibody titer was also highly correlated with both decreased placental transfer (P = 0.0080) and decreased infant IgG (P < 0.0001). Conclusions This is the first study to evaluate the relationship between maternal HIV-1 viremia, maternal HIV-1 antibody concentrations, and passive immunity among HIV-1–exposed infants. These data support the hypothesis that high HIV-1 viral load during the last trimester may impair maternofetal transfer of IgG and increases risk of measles and other serious infections among HIV-1–exposed infants. PMID:16280707

  10. Placental transfer of medical radionuclides in the guinea pig and mouse

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, A.M.; Preece, A.W

    1998-07-01

    Data on the fetal dose, following administration of radiopharmaceuticals, is required for patient counselling and assessing the risks of nuclear medical investigations during pregnancy. The placental transfer and fetal accumulation of {sup 99}Tc{sup m}, {sup 67}Ga and {sup 131}I has been measured in the guinea pig. {sup 99}Tc{sup m} and {sup 131}I were studied in the mouse to assess interspecies variation. Radionuclides were administered in early and late gestation. At intervals after administration the radioactive concentration of major maternal organs, fetuses, placentas and amniotic fluid were determined. The pattern of uptake into the fetus and placenta was similar for {sup 99}Tc{sup m} and {sup 131}I in both animal models, with fetal uptake higher than placental, and levels in both greater in late gestation. {sup 67}Ga preferentially localised into the placenta with levels peaking later than for {sup 99}Tc{sup m} and {sup 131}I. Fetal dose estimates ranged from 0.012 mGy for {sup 99}Tc{sup m} in late gestation to 87 mGy for {sup 131}I in early gestation. (author)

  11. Utero-placental transfer of alternate energy substrates and glucose homeostasis in the newborn pig

    Energy Technology Data Exchange (ETDEWEB)

    Thulin, A.J.

    1985-01-01

    In the first experiment, three sows in late gestation were infused with (/sup 14/C)..beta..-hydroxybutyrate to evaluate utero-placental transfer of ketones. ..beta..-Hydroxy-butyrate (BOHB) concentrations were low in both the mother and fetus throughout the experiments (0.0189, 0.0197, 0.0054, and 0.0063 mmole/liter blood for UV, UA, FV, and FA, respectively). Radioactive BOHB was detected in fetal blood within two minutes post-injection. Lipid extracts of liver and adipose tissue exhibited the greatest relative incorporation of (/sup 14/C)..beta..-hydroxybutyrate followed by lung and heart tissues (3540, 3674, 1214, and 528 dpm/g wet weight, respectively). In a second study, five gravid gilts during late gestation were used to determine utero-placental transfer of maternal free fatty acids (FFA). Using similar techniques as Exp. 1, injections were given containing (/sup 14/C) linoleic acid and (/sup 3/H) palmitic acid or (/sup 14/C) octanoic acid. In a third experiment, gravid gilts were fed supplemental energy as starch (C), soybean oil (SO) or medium-chain triglycerides (MCT) during late gestation to determine the influence on colostrum composition and neonatal pig glucose homeostasis. Energy content of colostrum was increased (P = 0.05 by feeding SO and MCT. After a 36 h fast, mean piglet glucose concentrations were higher (P < 0.05) for MCT pigs. Glucose and creatinine levels showed quadratic effects, while FFA and blood urea nitrogen (BUN) exhibited cubic patterns during the fasting period. Although creatine levels were similar, BUN concentrations were higher (P < 0.01) for MCT progeny.

  12. Oxygen transfer in a pressurized airlift bioreactor.

    Science.gov (United States)

    Campani, Gilson; Ribeiro, Marcelo Perencin Arruda; Horta, Antônio Carlos Luperni; Giordano, Roberto Campos; Badino, Alberto Colli; Zangirolami, Teresa Cristina

    2015-08-01

    Airlift bioreactors (ALBs) offer advantages over conventional systems, such as simplicity of construction, reduced risk of contamination, and efficient gas-liquid dispersion with low power consumption. ALBs are usually operated under atmospheric pressure. However, in bioprocesses with high oxygen demand, such as high cell density cultures, oxygen limitation may occur even when operating with high superficial gas velocity and air enriched with oxygen. One way of overcoming this drawback is to pressurize the reactor. In this configuration, it is important to assess the influence of bioreactor internal pressure on the gas hold-up, volumetric oxygen transfer coefficient (k(L)a), and volumetric oxygen transfer rate (OTR). Experiments were carried out in a concentric-tube airlift bioreactor with a 5 dm(3) working volume, equipped with a system for automatic monitoring and control of the pressure, temperature, and inlet gas flow rate. The results showed that, in disagreement with previous published results for bubble column and external loop airlift reactors, overpressure did not significantly affect k(L)a within the studied ranges of pressure (0.1-0.4 MPa) and superficial gas velocity in the riser (0.032-0.065 m s(-1)). Nevertheless, a positive effect on OTR was observed: it increased up to 5.4 times, surpassing by 2.3 times the oxygen transfer in a 4 dm(3) stirred tank reactor operated under standard cultivation conditions. These results contribute to the development of non-conventional reactors, especially pneumatic bioreactors operated using novel strategies for oxygen control.

  13. Influence of cloning by chromatin transfer on placental gene expression at Day 45 of pregnancy in cattle.

    Science.gov (United States)

    Mesquita, Fernando S; Machado, Sergio A; Drnevich, Jenny; Borowicz, Pawel; Wang, Zhongde; Nowak, Romana A

    2013-01-30

    Poor success rates in somatic cell cloning are often attributed to abnormal early embryonic development as well as late abnormal fetal growth and placental development. Although promising results have been reported following chromatin transfer (CT), a novel cloning method that includes the remodeling of the donor nuclei in vitro prior to their transfer into enucleated oocytes, animals cloned by CT show placental abnormalities similar to those observed following conventional nuclear transfer. We hypothesized that the placental gene expression pattern from cloned fetuses was ontologically related to the frequently observed placental phenotype. The aim of the present study was to compare global gene expression by microarray analysis of Day 44-47 cattle placentas derived from CT cloned fetuses with those derived from in vitro fertilization (i.e. control), and confirm the altered mRNA and protein expression of selected molecules by qRT-PCR and immunohistochemistry, respectively. The differentially expressed genes identified in the present study are known to be involved in a range of activities associated with cell adhesion, cell cycle control, intracellular transport and proteolysis. Specifically, an imprinted gene, involved with cell proliferation and placentomegaly in humans (CDKN1C) and a peptidase that serves as a marker for non-invasive trophoblast cells in human placentas (DPP4), had mRNA and protein altered in CT placentas. It was concluded that the altered pattern of gene expression observed in CT samples may contribute to the abnormal placental development phenotypes commonly identified in cloned offspring, and that expression of imprinted as well as trophoblast invasiveness-related genes is altered in cattle cloned by CT.

  14. Correlation between human maternal-fetal placental transfer and molecular weight of PCB and dioxin congeners/isomers.

    Science.gov (United States)

    Mori, Chisato; Nakamura, Noriko; Todaka, Emiko; Fujisaki, Takeyoshi; Matsuno, Yoshiharu; Nakaoka, Hiroko; Hanazato, Masamichi

    2014-11-01

    Establishing methods for the assessment of fetal exposure to chemicals is important for the prevention or prediction of the child's future disease risk. In the present study, we aimed to determine the influence of molecular weight on the likelihood of chemical transfer from mother to fetus via the placenta. The correlation between molecular weight and placental transfer rates of congeners/isomers of polychlorinated biphenyls (PCBs) and dioxins was examined. Twenty-nine sample sets of maternal blood, umbilical cord, and umbilical cord blood were used to measure PCB concentration, and 41 sample sets were used to analyze dioxins. Placental transfer rates were calculated using the concentrations of PCBs, dioxins, and their congeners/isomers within these sample sets. Transfer rate correlated negatively with molecular weight for PCB congeners, normalized using wet and lipid weights. The transfer rates of PCB or dioxin congeners differed from those of total PCBs or dioxins. The transfer rate for dioxin congeners did not always correlate significantly with molecular weight, perhaps because of the small sample size or other factors. Further improvement of the analytical methods for dioxin congeners is required. The findings of the present study suggested that PCBs, dioxins, or their congeners with lower molecular weights are more likely to be transferred from mother to fetus via the placenta. Consideration of chemical molecular weight and transfer rate could therefore contribute to the assessment of fetal exposure. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Glucose, Insulin, and Oxygen Interplay in Placental Hypervascularisation in Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Silvija Cvitic

    2014-01-01

    Full Text Available The placental vasculature rapidly expands during the course of pregnancy in order to sustain the growing needs of the fetus. Angiogenesis and vascular growth are stimulated and regulated by a variety of growth factors expressed in the placenta or present in the fetal circulation. Like in tumors, hypoxia is a major regulator of angiogenesis because of its ability to stimulate expression of various proangiogenic factors. Chronic fetal hypoxia is often found in pregnancies complicated by maternal diabetes as a result of fetal hyperglycaemia and hyperinsulinemia. Both are associated with altered levels of hormones, growth factors, and proinflammatory cytokines, which may act in a proangiogenic manner and, hence, affect placental angiogenesis and vascular development. Indeed, the placenta in diabetes is characterized by hypervascularisation, demonstrating high placental plasticity in response to diabetic metabolic derangements. This review describes the major regulators of placental angiogenesis and how the diabetic environment in utero alters their expression. In the light of hypervascularized diabetic placenta, the focus was placed on proangiogenic factors.

  16. Electron transfer pathways in microbial oxygen biocathodes

    Energy Technology Data Exchange (ETDEWEB)

    Freguia, Stefano, E-mail: stefano@kais.kyoto-u.ac.j [Bio-analytical and Physical Chemistry Laboratory, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8205 (Japan); Tsujimura, Seiya, E-mail: seiya@kais.kyoto-u.ac.j [Bio-analytical and Physical Chemistry Laboratory, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8205 (Japan); Kano, Kenji, E-mail: kkano@kais.kyoto-u.ac.j [Bio-analytical and Physical Chemistry Laboratory, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8205 (Japan)

    2010-01-01

    The ability of some bacteria to enhance the rate of cathodic oxygen reduction to water has been recently discovered, opening the way to an entirely renewable and environmentally friendly concept of biocathode. In this study we reveal that several mechanisms may induce catalytic effects by bacteria. These comprise mechanisms that are putatively beneficial to the bacteria as well as mechanisms which are merely side effects, including quinone autoxidation and direct O{sub 2} reduction by heme compounds. Here we showed that 1 muM of ACNQ is able to generate a significant catalytic wave for oxygen reduction, with onset at approximately 0 V vs. SHE. Similarly, adsorption of hemin on a carbon surface catalyses O{sub 2} reduction to H{sub 2}O{sub 2} with an onset of +0.2 V vs. SHE. To evaluate the catalytic pathways of live cells on cathodic oxygen reduction, two species of electrochemically active bacteria were selected as pure cultures, namely Acinetobacter calcoaceticus and Shewanella putrefaciens. The former appears to exploit a self-excreted redox compound with redox characteristics matching those of pyrroloquinoline quinone (PQQ) for extracellular electron transfer. The latter appears to utilise outer membrane-bound redox compounds. Interaction of quinones and cytochromes with the membrane-bound electron transfer chain is yet to be proven.

  17. Cadmium chronic administration to lactating ewes. Reproductive performance, cadmium tissue accumulation and placental transfer

    Energy Technology Data Exchange (ETDEWEB)

    Floris, B.; Bomboi, G.; Sechi, P.; Marongiu, M. L. [Sassari Univ., Sassari (Italy). Dipt. di Biologia Animale; Pirino, S. [Sassari Univ., Sassari (Italy). Ist. di Patologia Generale, Anatomia Patologica e Clinica Ostetrico-chirurgica Veterinaria

    2000-12-01

    20 lactating ewes were allotted to two groups: 10 subjects received orally 100 mg/day of CdCl{sub 2} for 108 consecutive days, and the remaining 10 acted as control. Reproductive performance in ewes and cadmium tissue accumulation, both in ewes and their lambs, were investigated. The results showed that in ewes: 1) the regular cadmium intestinal intake negatively influences all reproductive parameters; 2) cadmium is particularly accumulated in kidney and liver, bur also in mammary gland, although at distinctly lower level; 3) chronic administration does not increase cadmium placental transfer in lactating pregnant subjects. [Italian] 20 pecore in lattazione sono state suddivise in 2 gruppi: 10 soggetti ricevettero per os 100 mg/giorno di CdCl{sub 2} per 108 giorni consecutivi, e i restanti 10 funsero da controllo. Sono stati studiati i parametri riproduttivi delle pecore e l'accumulo di cadmio nei tessuti, sia delle pecore che dei loro agnelli. I risultati hanno mostrato che negli ovini: 1) il regolare assorbimento intestinale di cadmio influenza negativamente tutti i parametri riproduttivi; 2) il cadmio viene accumulato principalmente nei reni e nel fegato, ma anche dalla ghiandola mammaria, sebbene in misura nettamente inferiore; 3) la somministrazione cronica di cadmio nei soggetti gravidi non incrementa il suo passaggio transplacentare.

  18. Virus-Free Human Placental Cell Lines To Study Genetic Functions | NCI Technology Transfer Center | TTC

    Science.gov (United States)

    The National Institute of Child Health and Human Development's Section on Cellular Differentiation is seeking statements of capability or interest from parties interested in collaborative research to further develop, evaluate, or commercialize immortalized virus-free human placental cell lines.The National Institute of Child Health and Human Development's Section on Cellular Differentiation is seeking statements of capability or interest from parties interested in collaborative research to further develop, evaluate, or commercialize immortalized virus-free human placental cell lines.

  19. Measurement of oxygen transfer from air into organic solvents

    DEFF Research Database (Denmark)

    Ramesh, Hemalata; Mayr, Torsten; Hobisch, Mathias

    2016-01-01

    applications). Subsequently, we measured the oxygen transfer rates from air into these organic solvents. Conclusion The measurement of oxygen transfer rates from air into organic solvents using the dynamic method was established using the solvent resistant optical sensor. The feasibility of online oxygen...... biological reactions require the supply of oxygen, most normally from air. However, reliable on-line measurements of oxygen concentration in organic solvents (and hence oxygen transfer rates from air to the solvent) has to date proven impossible due limitations in the current analytical methods. Results...

  20. Placental Transfer of Persistent Organic Pollutants: A Preliminary Study on Mother-Newborn Pairs

    Directory of Open Access Journals (Sweden)

    Elena De Felip

    2013-02-01

    Full Text Available The aim of this study was to characterize the placental transfer of some environmental pollutants, and to explore the possibility of quantitatively predicting in utero exposure to these contaminants from concentrations assessed in maternal blood. Levels of toxic substances such as pesticides (p,p’-DDE, β-HCH, and HCB, polychlorinated biphenyls (PCBs, perfluorooctane sulfonate (PFOS, and perfluorooctanoic acid (PFOA were determined in serum samples of 38 pregnant women living in Rome and in samples of cord blood from their respective newborns. The study was carried out in the years 2008–2009. PCB mean concentrations in maternal serum and cord serum ranged from 0.058 to 0.30, and from 0.018 to 0.064 ng/g·fw respectively. Arithmetic means of PFOS and PFOA concentrations in mothers and newborns were 3.2 and 1.4 ng/g·fw, and 2.9 and 1.6 ng/g·fw. A strong correlation was observed between concentrations in the maternal and the foetal compartment for PFOS (Spearman r = 0.74, p < 0.001, PFOA (Spearman r = 0.70, p < 0.001, PCB 153 (Spearman r = 0.60, p < 0.001, HCB (Spearman r = 0.68, p < 0.001, PCB 180 (Spearman r = 0.55, p = 0.0012, and p,p’-DDE (Spearman r = 0.53, p = 0.0099. A weak correlation (p < 0.1 was observed for PCBs 118 and 138.

  1. Multiple SLC and ABC Transporters Contribute to the Placental Transfer of Entecavir.

    Science.gov (United States)

    Ma, Zhiyuan; Yang, Xi; Jiang, Ting; Bai, Mengru; Zheng, Caihong; Zeng, Su; Sun, Dongli; Jiang, Huidi

    2017-03-01

    Entecavir (ETV), a nucleoside analog with high efficacy against hepatitis B virus, is recommended as a first-line antiviral drug for the treatment of chronic hepatitis B. However, scant information is available on the use of ETV in pregnancy. To better understand the safety of ETV in pregnant women, we aimed to demonstrate whether ETV could permeate placental barrier and the underlying mechanism. Our study showed that small amount of ETV could permeate across placenta in mice. ETV accumulation in activated or nonactivated BeWo cells (treated with or without forskolin) was sharply reduced in the presence of 100 µM of adenosine, cytidine, and in Na(+) free medium, indicating that nucleoside transporters possibly mediate the uptake of ETV. Furthermore, ETV was proved to be a substrate of concentrative nucleoside transporter (CNT) 2 and CNT3, of organic cation transporter (OCT) 3, and of breast cancer resistance protein (BCRP) using transfected cells expressing respective transporters. The inhibition of ETV uptake in primary human trophoblast cells further confirmed that equilibrative nucleoside transporter (ENT) 1/2, CNT2/3, OCT3, and organic cation/carnitine transporter (OCTN) 2 might be involved in ETV transfer in human placenta. Therefore, ETV uptake from maternal circulation to trophoblast cells was possibly transported by CNT2/3, ENT1/2, and OCTN2, whereas ETV efflux from trophoblast cells to fetal circulation was mediated by OCT3, and efflux from trophoblast cells to maternal circulation might be mediated by BCRP, multidrug resistance-associated protein 2, and P-glycoprotein. The information obtained in the present study may provide a basis for the use of ETV in pregnancy. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

  2. Antibody-dependent transplacental transfer of malaria blood-stage antigen using a human ex vivo placental perfusion model.

    Directory of Open Access Journals (Sweden)

    Karen May

    Full Text Available Prenatal exposure to allergens or antigens released by infections during pregnancy can stimulate an immune response or induce immunoregulatory networks in the fetus affecting susceptibility to infection and disease later in life. How antigen crosses from the maternal to fetal environment is poorly understood. One hypothesis is that transplacental antigen transfer occurs as immune complexes, via receptor-mediated transport across the syncytiotrophoblastic membrane and endothelium of vessels in fetal villi. This hypothesis has never been directly tested. Here we studied Plasmodium falciparum merozoite surface protein 1 (MSP1 that is released upon erythrocyte invasion. We found MSP1 in cord blood from a third of newborns of malaria-infected women and in >90% following treatment with acid dissociation demonstrating MSP1 immune complexes. Using an ex vivo human placental model that dually perfuses a placental cotyledon with independent maternal and fetal circuits, immune-complexed MSP1 transferred from maternal to fetal circulation. MSP1 alone or with non-immune plasma did not transfer; pre-incubation with human plasma containing anti-MSP1 was required. MSP1 bound to IgG was detected in the fetal perfusate. Laser scanning confocal microscopy demonstrated MSP1 in the fetal villous stroma, predominantly in fetal endothelial cells. MSP1 co-localized with IgG in endothelial cells, but not with placental macrophages. Thus we show, for the first time, antibody-dependent transplacental transfer of an antigen in the form of immune complexes. These studies imply frequent exposure of the fetus to certain antigens with implications for management of maternal infections during pregnancy and novel approaches to deliver vaccines or drugs to the fetus.

  3. Nanoparticulate-catalyzed oxygen transfer processes

    Science.gov (United States)

    Hunt, Andrew T.; Breitkopf, Richard C.

    2009-12-01

    Nanoparticulates of oxygen transfer materials that are oxides of rare earth metals, combinations of rare earth metals, and combinations of transition metals and rare earth metals are used as catalysts in a variety of processes. Unexpectedly large thermal efficiencies are achieved relative to micron sized particulates. Processes that use these catalysts are exemplified in a multistage reactor. The exemplified reactor cracks C6 to C20 hydrocarbons, desulfurizes the hydrocarbon stream and reforms the hydrocarbons in the stream to produce hydrogen. In a first reactor stage the steam and hydrocarbon are passed through particulate mixed rare earth metal oxide to crack larger hydrocarbon molecules. In a second stage, the steam and hydrocarbon are passed through particulate material that desulfurizes the hydrocarbon. In a third stage, the hydrocarbon and steam are passed through a heated, mixed transition metal/rare earth metal oxide to reform the lower hydrocarbons and thereby produce hydrogen. Stages can be alone or combined. Parallel reactors can provide continuous reactant flow. Each of the processes can be carried out individually.

  4. Oxygen tension and normalisation pressure modulate nifedipine-sensitive relaxation of human placental chorionic plate arteries.

    Science.gov (United States)

    Cooper, E J; Wareing, M; Greenwood, S L; Baker, P N

    2006-01-01

    Fetoplacental blood vessel constriction in response to reduced oxygenation has been demonstrated in placenta perfused in vitro. In pulmonary vessels, hypoxic vasoconstriction involves Ca2+ influx into smooth muscle through membrane ion channels including voltage-gated Ca2+ channels (VGCCs). We hypothesised that VGCCs are involved in agonist-induced constriction of fetoplacental resistance vessels and that their contribution is modulated by oxygen. Chorionic plate small arteries were studied using wire myography. Arteries were normalised at high (0.9 of L(13.3 kPa)) or low (0.9 of L(5.1 kPa)) stretch and experiments performed at 156, 38 or 15 mmHg oxygen. At low stretch, U46619 (thromboxane-mimetic) or KCl (smooth muscle depolarisation) constriction was greater at 38 than 156 or 15 mmHg oxygen. An L-type VGCC blocker nifedipine, inhibited KCl constriction by >85% but was less effective in U46619 constrictions (43-67%). At high stretch, nifedipine inhibition of KCl- and U46619-induced constriction was less at 15 than 38 or 156 mmHg oxygen. Oxygen did not affect constriction to U46619 or nifedipine-induced relaxation when vessels were normalised at high stretch. In conclusion, oxygen modulates chorionic plate arterial constriction at low stretch but regulation is lost at high stretch. U46619 constriction is underlain by VGCCs and nifedipine-insensitive processes; their relative contribution is influenced by oxygen.

  5. First trimester alcohol exposure alters placental perfusion and fetal oxygen availability affecting fetal growth and development in a non-human primate model.

    Science.gov (United States)

    Lo, Jamie O; Schabel, Matthias C; Roberts, Victoria H J; Wang, Xiaojie; Lewandowski, Katherine S; Grant, Kathleen A; Frias, Antonio E; Kroenke, Christopher D

    2017-03-01

    Prenatal alcohol exposure leads to impaired fetal growth, brain development, and stillbirth. Placental impairment likely contributes to these adverse outcomes, but the mechanisms and specific vasoactive effects of alcohol that links altered placental function to impaired fetal development remain areas of active research. Recently, we developed magnetic resonance imaging techniques in nonhuman primates to characterize placental blood oxygenation through measurements of T2* and perfusion using dynamic contrast-enhanced magnetic resonance imaging. The objective of this study was to evaluate the effects of first-trimester alcohol exposure on macaque placental function and to characterize fetal brain development in vivo. Timed-pregnant Rhesus macaques (n=12) were divided into 2 groups: control (n=6) and ethanol exposed (n=6). Animals were trained to self-administer orally either 1.5 g/kg/d of a 4% ethanol solution (equivalent to 6 drinks/d) or an isocaloric control fluid from preconception until gestational day 60 (term is G168). All animals underwent Doppler ultrasound scanning followed by magnetic resonance imaging that consisted of T2* and dynamic contrast-enhanced measurements. Doppler ultrasound scanning was used to measure uterine artery and umbilical vein velocimetry and diameter to calculate uterine artery volume blood flow and placental volume blood flow. After noninvasive imaging, animals underwent cesarean delivery for placenta collection and fetal necropsy at gestational day 110 (n=6) or 135 (n=6). Fetal weight and biparietal diameter were significantly smaller in ethanol-exposed animals compared with control animals at gestational day 110. By Doppler ultrasound scanning, placental volume blood flow was significantly lower (P=.04) at gestational day 110 in ethanol-exposed vs control animals. A significant reduction in placental blood flow was evident by dynamic contrast-enhanced magnetic resonance imaging. As we demonstrated recently, T2* values vary

  6. Impact of equine assisted reproductive technologies (standard embryo transfer or intracytoplasmic sperm injection (ICSI) with in vitro culture and embryo transfer) on placenta and foal morphometry and placental gene expression.

    Science.gov (United States)

    Valenzuela, Orlando A; Couturier-Tarrade, Anne; Choi, Young-Ho; Aubrière, Marie-Christine; Ritthaler, Justin; Chavatte-Palmer, Pascale; Hinrichs, Katrin

    2017-07-24

    Assisted reproductive technologies (ARTs) such as intracytoplasmic sperm injection (ICSI), in vitro embryo culture and embryo transfer (ET) may be associated with alterations in fetal and placental development. In horses, ET has been used for decades. More recently, in vitro embryo production by ICSI and in vitro culture, followed by embryo transfer (ICSI-C) has become an accepted method for clinical foal production. However, no information is available on the effects of ICSI-C or even of standard ET itself on placental and neonatal parameters in horses. We therefore evaluated placental and neonatal morphology and placental gene expression in reining- and cutting-type American Quarter Horse foals produced using different technologies. Thirty foals and placentas (naturally conceived (NC), ET and ICSI-C; 10 in each group) were examined morphometrically. The only parameter that differed significantly between groups was the length of the foal upper hindlimb, which was longer in ET and ICSI-C than in NC foals. Evaluation of placental mRNA expression for 17 genes related to growth and vascularisation showed no difference in gene expression between groups. These data indicate that within this population, use of ARTs was not associated with meaningful changes in foal or placental morphometry or in expression of the placental genes evaluated.

  7. Changes in the metabolic footprint of placental explant-conditioned medium cultured in different oxygen tensions from placentas of small for gestational age and normal pregnancies.

    LENUS (Irish Health Repository)

    Horgan, R P

    2012-01-31

    Being born small for gestational age (SGA) confers significantly increased risks of perinatal morbidity and mortality. Accumulating evidence suggests that an SGA fetus results from a poorly perfused and abnormally developed placenta. Some of the placental features seen in SGA, such as abnormal cell turnover and impaired nutrient transport, can be reproduced by culture of placental explants in hypoxic conditions. Metabolic footprinting offers a hypothesis-generating strategy to investigate factors absorbed by and released from this tissue in vitro. Previously, metabolic footprinting of the conditioned culture media has identified differences in placental explants cultured under normoxic and hypoxic conditions and between normal pregnancies and those complicated by pre-eclampsia. In this study we aimed to examine the differences in the metabolic footprint of placental villous explants cultured at different oxygen (O(2)) tensions between women who deliver an SGA baby (n = 9) and those from normal controls (n = 8). Placental villous explants from cases and controls were cultured for 96 h in 1% (hypoxic), 6% (normoxic) and 20% (hyperoxic) O(2). Metabolic footprints were analysed by Ultra Performance Liquid Chromatography coupled to an electrospray hybrid LTQ-Orbitrap Mass Spectrometry (UPLC-MS). 574 metabolite features showed significant difference between SGA and normal at one or more of the oxygen tensions. SGA explant media cultured under hypoxic conditions was observed, on a univariate level, to exhibit the same metabolic signature as controls cultured under normoxic conditions in 49% of the metabolites of interest, suggesting that SGA tissue is acclimatised to hypoxic conditions in vivo. No such behaviour was observed under hyperoxic culture conditions. Glycerophospholipid and tryptophan metabolism were highlighted as areas of particular interest.

  8. Oxygen mass transfer in fermentation of bacillus thuringiensis

    Directory of Open Access Journals (Sweden)

    R. Ríos

    2011-12-01

    Full Text Available The purpose of this work was to obtain a correlation based on literature, depicting the relationships betwen the physical oxygen transfer rate (OTR and microbial oxygen uptake rate (OUR in order to determine the conditions (mass transfer coefficient, resulting on diferents combinations of aereations and agitations rates, under which growth will not be limited by oxygen. This correlation was adapted to culture with B. thuringiensis in order to estimate what biomass concentration are feasible for the physical limits set by operations conditions before microbial activity becomes limited by oxygen.

  9. Effects of gestational stage and injection route on the corporeal distribution and placental transfer of selenium in pregnant mice

    Energy Technology Data Exchange (ETDEWEB)

    Nishikido, N.; Suzuki, T.

    1985-01-01

    Corporeal distribution and placental transfer of selenium after a single injection of sodium selenite (SS) were investigated over a period of 24 h with regard to the gestational stages of mice and the injection routes of SS. On day 16 of gestation, feto-placental accumulation of selenium was remarkably increased compared with that on day 12 following subcutaneous (sc) injection of SS. Selenium concentrations in the maternal liver, kidneys and lungs were higher on day 16 than on day 12. These results explain the occurrence of the enhanced abortion or maternal death due to SS injection (sc) on day 16 compared with that on day 12, in the previous study. Intravenous (iv) injection of SS caused increased selenium concentrations in most of the maternal organs and tissues but not in the placenta or the fetus compared with sc injection. This may explain the disappearance of the abortion-inducing effect of SS when iv injection is used. 12 references, 1 figure, 5 tables.

  10. Nuclear transfer alters placental gene expression and associated histone modifications of the placental-specific imprinted gene pleckstrin homology-like domain, family A, member 2 (PHLDA2) in cattle.

    Science.gov (United States)

    Arnold, Daniel R; Gaspar, Roberta C; da Rocha, Carlos V; Sangalli, Juliano R; de Bem, Tiago H C; Corrêa, Carolina A P; Penteado, João C T; Meirelles, Flavio V; Lopes, Flavia L

    2017-03-01

    Abnormal placental development is frequent in nuclear transfer (NT) pregnancies and is likely to be associated with altered epigenetic reprogramming. In the present study, fetal and placental measurements were taken on Day 60 of gestation in cows with pregnancies produced by AI, IVF and NT. Placentas were collected and subjected to histological evaluation, the expression of genes important in trophoblast differentiation and expression of the placental imprinted gene pleckstrin homology-like domain, family A, member 2 (PHLDA2), as well as chromatin immunoprecipitation (ChIP) for histone marks within the promoter of PHLDA2. Fewer binucleated cells were observed in NT cotyledons, followed by IVF and AI cotyledons (P<0.05). Expression of heart and neural crest derivatives expressed 1 (HAND1), placental lactogen (PL), pregnancy-associated glycoprotein 9 (PAG-9) and PHLDA2 was elevated in NT cotyledons compared with AI cotyledons. Expression of PHLDA2 was higher in IVF than AI samples (P<0.05). ChIP revealed an increase in the permissive mark dimethylation of lysine 4 on histone H3 (H3K4me2), surprisingly associated with the silent allele of PHLDA2, and a decrease in the inhibitory mark H3K9me2 in NT samples. Thus, genes critical for placental development were altered in NT placentas, including an imprinted gene. Allele-specific changes in the permissive histone mark in the PHLDA2 promoter indicate misregulation of imprinting in clones. Abnormal trophoblast differentiation could have resulted in lower numbers of binucleated cells following NT. These results suggest that the altered expression of imprinted genes associated with NT are also caused by changes in histone modifications.

  11. Lactate production and absence of gluconeogenesis from placental transferred substrates in fetuses from fed and 48-H starved rats

    Energy Technology Data Exchange (ETDEWEB)

    Palacin, M.; Lasuncion, M.A.; Herrera, E.

    1987-07-01

    Fed and 48-h starved rats were infused on day 21.5 of gestation for 20 min through the left uterine artery with (U-/sup 14/C-)-D-glucose, (U-/sup 14/C)-glycerol, or (U-/sup 14/C)-L-alanine. The mother and fetuses from both uterine horns were processed separately for radioactivity measurements in plasma and liver. Differences in radioactivity values between fetuses from the left and the right sides are used as indexes of placental transference of the infused tracers prior to their distribution and transformation in the maternal circulation. After infusion of (U-/sup 14/C)-D-glucose, (U-/sup 14/C)-glycerol, or (U-/sup 14/C)-L-alanine, plasma radioactivity values and specific activities corresponding to the respective infused tracer appeared much higher in fetuses from the left than the right uterine side. Plasma /sup 14/C-lactate values also were higher in the left than the right fetuses indicating that fetoplacental structures produced lactate from those placentally transferred /sup 14/C-metabolites. No difference in plasma /sup 14/C-glucose between left and right uterine horn fetuses was observed after maternal infusion with either (U-/sup 14/C)-glycerol or (U-/sup 14/C)-L-alanine, either in fed or 48-h starved rats. In the mother both (U-/sup 14/C)-glycerol and (U-/sup 14/C)-L-alanine were efficiently converted to /sup 14/C-glucose, and this process was significantly enhanced with starvation. /sup 14/C-fatty acids present in fetal liver after maternal infusions with either (U-/sup 14/C)-D-glucose or (U-/sup 14/C)-glycerol were decreased by starvation whereas no fatty acid synthesis from (U-/sup 14/C)-L-alanine was detected.

  12. Oxygen plasma-treatment effects on Si transfer.

    Science.gov (United States)

    Langowski, Bryan A; Uhrich, Kathryn E

    2005-07-05

    Oxygen plasma-treatment is commonly used to increase the hydrophilicity of poly(dimethylsiloxane) (PDMS) stamps used for microcontact printing (muCP) aqueous-based inks. Review of the literature reveals that a wide range of plasma parameters are currently employed to modify stamp surfaces. However, little is known about the effect of these parameters (e.g., power, chamber pressure, duration) on the undesirable transfer of low-molecular-weight silicon-containing fragments from the stamps that commonly occurs during muCP. To study the effect of oxygen plasma-treatment on Si transfer, unpatterned PDMS stamps were treated with oxygen plasma under various conditions and used to stamp deionized water on plasma-activated poly(methyl methacrylate) (PMMA) substrates. Once stamped, the PMMA substrates were analyzed with X-ray photoelectron spectroscopy (XPS) to quantify and characterize silicon present on the substrate surface. In addition, used PDMS stamps were analyzed with scanning electron microscopy (SEM) to observe topographical changes that occur during oxygen plasma-treatment. XPS results show that all plasma treatments studied significantly reduced the amount of Si transfer from the treated stamps during muCP as compared to untreated PDMS stamps and that the source of transfer is residual PDMS fragments not removed by oxygen plasma. SEM results show that, although the treated stamps undergo a variety of topographical changes, no correlation exists between stamp topography and extent of Si transfer from the stamps.

  13. A new method to measure oxygenator oxygen transfer performance during cardiopulmonary bypass: clinical testing using the Medtronic Fusion oxygenator.

    Science.gov (United States)

    Hamilton, Carole; Marin, Denise; Weinbrenner, Frank; Engelhardt, Branka; Rosenzweig, Dow; Beck, Ulrich; Borisov, Pavel; Hohe, Stephen

    2017-03-01

    There is no acceptable method of testing oxygen transfer performance in membrane oxygenators quickly and easily during cardiopulmonary bypass. Pre-clinical testing of oxygenators is performed under controlled situations in the laboratory, correlating oxygen transfer to blood flow using 100% oxygen. This laboratory method cannot be used clinically as oxygen transfer values vary significantly at each blood flow and the FiO2 is not kept at 1. Therefore, a formula was developed which corrects the existing FiO2 to attain a PaO2 of 150 mmHg: the corrected FiO2 at 150 mmHg. In graph form, this corrected FiO2 (x-axis) is correlated to the patient's oxygen consumption levels (y-axis), which determines the membrane oxygenator oxygen transfer performance. Blood gas and hemodynamic parameters taken during cardiopulmonary bypass using the Medtronic Fusion were used to calculate the oxygen consumption (inlet conditions to the oxygenator) and the corrected FiO2 for a PaO2 of 150 mmHg. Validation of the formula "FiO2-PaO2/(Pb-pH2O)+0.21" was carried out by plotting the calculated values on a graph using PaO2 values between 145 to 155 mmHg and then, using the corrected FiO2 for PaO2s outside of this range. All trend-lines correlated significantly to confirm that the Medtronic Fusion had an extrapolated oxygen transfer of 419 milliliters O2/min at an FiO2 of 1 to achieve a PaO2 of 150 mmHg. Use of the corrected FiO2 correlated to the oxygen transfer conditions of the membrane oxygenator can easily be used on a routine basis, providing valuable information clinically. When used by the manufacturer under laboratory conditions, further clinically relevant data is provided in terms of FiO2 and resultant PaO2s instead of the present limitations using blood flow. In this way, a clinically justifiable method has been developed to finally establish a standard in testing membrane oxygenator performance.

  14. Peroxidase-catalyzed S-oxygenation: Mechanism of oxygen transfer for lactoperoxidase

    Energy Technology Data Exchange (ETDEWEB)

    Doerge, D.R.; Cooray, N.M. (Univ. of Hawaii, Honolulu (United States)); Brewster, M.E. (Pharmatec Inc., Alachua, FL (United States))

    1991-09-17

    The mechanism of organosulfur oxygenation by peroxidases (lactoperoxidase (LPX), chloroperoxidase, thyroid peroxidase, and horseradish peroxidase) and hydrogen peroxide was investigated by use of para-substituted thiobenzamides and thioanisoles. The rate constants for thiobenzamide oxygenation by LPX/H{sub 2}O{sub 2} were found to correlate with calculated vertical ionization potentials, suggesting rate-limiting single-electron transfer between LPX compound I and the organosulfur substrate. The incorporation of oxygen from {sup 18}O-labeled hydrogen peroxide, water, and molecular oxygen into sulfoxides during peroxidase-catalyzed S-oxygenation reactions was determined by LC- and GC-MS. All peroxidases tested catalyzed essentially quantitative oxygen transfer from {sup 18}O-labeled hydrogen peroxide into thiobenzamide S-oxide, suggesting that oxygen rebound from the oxoferryl heme is tightly coupled with the initial electron transfer in the active site. Experiments using H{sub 2}{sup 18}O{sub 2}, and H{sub 2}{sup 18}O showed the LPX catalyzed approximately 85,22, and 0% {sup 18}O-incorporation into thioanisole sulfoxide oxygen, respectively. These results are consistent with an active site controlled mechanism in which the protein radical form of LPX compound I is an intermediate in LPX-mediated sulfoxidation reactions.

  15. Placental transfer of the polybrominated diphenyl ethers BDE-47, BDE-99 and BDE-209 in a human placenta perfusion system: an experimental study

    Directory of Open Access Journals (Sweden)

    Frederiksen Marie

    2010-07-01

    Full Text Available Abstract Background Polybrominated diphenyl ethers (PBDEs have been widely used as flame retardants in consumer products. PBDEs may affect thyroid hormone homeostasis, which can result in irreversible damage of cognitive performance, motor skills and altered behaviour. Thus, in utero exposure is of very high concern due to critical windows in fetal development. Methods A human ex vivo placenta perfusion system was used to study the kinetics and extent of the placental transfer of BDE-47, BDE-99 and BDE-209 during four-hour perfusions. The PBDEs were added to the maternal circulation and monitored in the maternal and fetal compartments. In addition, the perfused cotyledon, the surrounding placental tissue as well as pre-perfusion placental tissue and umbilical cord plasma were also analysed. The PBDE analysis included Soxhlet extraction, clean-up by adsorption chromatography and GC-MS analysis. Results and Discussion Placental transfer of BDE-47 was faster and more extensive than for BDE-99. The fetal-maternal ratios (FM-ratio after four hours of perfusion were 0.47 and 0.25 for BDE-47 and BDE-99, respectively, while the indicative permeability coefficient (IPC measured after 60 minutes of perfusion was 0.26 h-1 and 0.10 h-1, respectively. The transport of BDE-209 seemed to be limited. These differences between the congeners may be related to the degree of bromination. Significant accumulation was observed for all congeners in the perfused cotyledon as well as in the surrounding placental tissue. Conclusion The transport of BDE-47 and BDE-99 indicates in utero exposure to these congeners. Although the transport of BDE-209 was limited, however, possible metabolic debromination may lead to products which are both more toxic and transportable. Our study demonstrates fetal exposure to PBDEs, which should be included in risk assessment of PBDE exposure of women of child-bearing age.

  16. Polybrominated diphenyl ethers (PBDEs) in human samples of mother-newborn pairs in South China and their placental transfer characteristics.

    Science.gov (United States)

    Chen, Zhuo-Jia; Liu, Han-Yan; Cheng, Zhang; Man, Yu-Bon; Zhang, Kun-Shui; Wei, Wei; Du, Jun; Wong, Ming-Hung; Wang, Hong-Sheng

    2014-12-01

    There are limited data concerning the placenta transfer characteristics and accumulation of polybrominated diphenyl ethers (PBDEs) in infants. However, PBDEs received increasing health concerns due to their endocrine disrupt and neurodevelopment toxicity effects. The present study assessed the accumulation of PBDEs in 30 paired placenta, breast milk, fetal cord blood, and neonatal urine samples collected from five major cities of the South China. The age of mothers ranged from 21 to 39 (mean 27.6±4.56). The ∑PBDE concentrations were 15.8±9.88 ng g(-1) lipid in placenta, 13.2±7.64 ng g(-1) lipid in breast milk, 16.5±19.5 ng g(-1) lipid in fetal cord blood, and 1.80±1.99 ng ml(-1) in neonatal urine. BDE-47 was the predominant congener in all types of human sample. Octa-BDEs such as BDE-196/-197 were detected highly in placenta and cord blood while moderately in breast milk and neonatal urine. Significant (pPBDEs in cord blood-maternal placenta and breast milk-urine paired individual samples. The extent of placental transfer of higher brominated BDEs such as BDE-196/-197 was greater than that of BDE-47. The estimated daily intake (EDI) analysis for breast-fed infants revealed that newborns in these areas were exposed to relatively high levels of PBDEs via breast milk. Our study not only provided systematic fundamental data for PBDE distribution but also revealed the placenta transfer characteristics of PBDE congeners in South China.

  17. Functional Role of P-Glycoprotein and Binding Protein Effect on the Placental Transfer of Lopinavir/Ritonavir in the Ex Vivo Human Perfusion Model

    Directory of Open Access Journals (Sweden)

    Pierre-Francois Ceccaldi

    2009-01-01

    Methods. Cotyledons were perfused with lopinavir, ritonavir, and the internal control antipyrin, at various albumin concentrations (10, 30, 40 g/L. After the control phase of each experiment, the P-glycoprotein inhibitor ciclosporin A was added at middle perfusion (45 minutes. Fetal Transfer Rate (FTR and Clearance Index (CLI were compared between the 2 phases. Results. In the control phase, the clearance index of lopinavir decreased from 0.401 ± 0.058 to 0.007 ± 0.027, as albumin concentrations increased from 10 g/L to higher concentrations (30, 40 g/L. When adding ciclosporin A at physiological albumin concentrations, the clearance index of lopinavir increased significantly 10.3 fold (95% of CI difference [−0.156, −0.002], P=.046 and became positive for ritonavir. Conclusions. Even at high albumin concentrations, inhibition of placental P-glycoprotein increased placental transfer of lopinavir, suggesting that this efflux pump actively reduces placental transfer of the drug. This mechanism may play a role in fetal exposure to maternal antiretroviral therapy.

  18. Twin pregnancy and partial hydatidiform mole following in vitro fertilization and embryos transfer: a novel case of placental mosaicism

    Institute of Scientific and Technical Information of China (English)

    SUN Cheng-juan; ZHAO You-ping; YU Song; FAN Ling; WU Qing-qing; LI Guang-hui; ZHANG Wei-yuan

    2012-01-01

    Twin pregnancy with mosaic partial hydatidiform mole (PHM) and survival of two healthy fetuses following in vitro fertilization and embryos transfer (IVF-ET) is a rare situation and is considered a challenge for management.A 32-year-old Chinese woman conceived twin pregnancy following IVF-ET.At 22 weeks' gestation,an additional intrauterine echogenic mass with features of PHM were shown by successive ultrasound examinations.At 35 weeks'gestation,two live male infants and two placentas were delivered by caesarean section (CS).Histologic examination of the abnormal placenta confirmed mosaic PHM.Genetic study showed the abnormal placental mosaicism (expressed in molar-69XXY and normal vili-46XY),co-existing with a hypospadia new-born (46XY) in one amniotic sac.However,the other one was normal.Serial serum β-hCG levels showed a declining trend and serum 3-human chorionic gonadotropin (hCG) were undetectable at 6 months after delivery.The case demonstrated that it is possible to prolonged gestation by PHM under close surveillance during the entire pregnancy.

  19. Twin pregnancy and partial hydatidiform mole following in vitro fertilization and embryos transfer: a novel case of placental mosaicism.

    Science.gov (United States)

    Sun, Cheng-juan; Zhao, You-ping; Yu, Song; Fan, Ling; Wu, Qing-qing; Li, Guang-hui; Zhang, Wei-yuan

    2012-12-01

    Twin pregnancy with mosaic partial hydatidiform mole (PHM) and survival of two healthy fetuses following in vitro fertilization and embryos transfer (IVF-ET) is a rare situation and is considered a challenge for management. A 32-year-old Chinese woman conceived twin pregnancy following IVF-ET. At 22 weeks' gestation, an additional intrauterine echogenic mass with features of PHM were shown by successive ultrasound examinations. At 35 weeks' gestation, two live male infants and two placentas were delivered by caesarean section (CS). Histologic examination of the abnormal placenta confirmed mosaic PHM. Genetic study showed the abnormal placental mosaicism (expressed in molar-69XXY and normal vili-46XY), co-existing with a hypospadia new-born (46XY) in one amniotic sac. However, the other one was normal. Serial serum β-hCG levels showed a declining trend and serum β-human chorionic gonadotropin (hCG) were undetectable at 6 months after delivery. The case demonstrated that it is possible to prolonged gestation by PHM under close surveillance during the entire pregnancy.

  20. Exposure levels of environmental endocrine disruptors in mother-newborn pairs in China and their placental transfer characteristics.

    Directory of Open Access Journals (Sweden)

    Lu-Xi Li

    Full Text Available There is a growing concern about the potential health effects of exposure to various environmental chemicals during pregnancy and infancy. The placenta is expected to be an effective barrier protecting the developing embryo against some endocrine disruptors (EDs circulating in maternal blood. The current study was designed to assess in utero exposure levels of non-persistent organic pollutants (non-POPs and persistent organic pollutants (POPs in Chinese newborns and potential role of placenta barrier against fetal exposure to these commonly-used environmental endocrine disruptors. A total of 230 newborn-mother pairs were enrolled during 2010-2011, 201 pairs of which were recruited from Shanghai, and the other 29 pairs came from Wenzhou. Maternal blood, cord blood, and meconium specimens were collected in the subject population from Shanghai and analyzed for non-POPs, including mono-2-ethylhexyl phthalate (MEHP, octylphenol (OP and 4-nonylphenol (4-NP. A total of 19 polybrominated diphenyl ethers (PBDEs congeners, which belong to POPs, were detected in maternal and cord blood specimens from the other 29 pairs. Fetal-maternal ratios (F-M ratios and regression coefficients were presented to assess potential function of placenta on barricading the mother/fetal transfer of these EDs. Concentrations of the detected non-POPs in cord blood samples were approximately 20% lower than those in maternal blood, and regression coefficients of which were all over 0.80. In contrast, PBDEs levels in cord blood samples were significantly higher than those in maternal blood. MEHP levels in meconium were much higher than those in cord blood samples, and highly correlated. Therefore, observations demonstrated that the placental barrier slightly decreased the fetal exposure to most non-POPs, while PBDEs seemed to be totally transferred across the placenta and finally reached the fetus. For in utero exposure assessment of Di-2-ethylhexyl phthalate (DEHP, MEHP level in

  1. Nonylphenol in pregnant women and their matching fetuses: Placental transfer and potential risks of infants

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yu-Fang [Institute of Environmental and Occupational Health Sciences, National Yang Ming University, No. 155, Sec. 2, Li-Nong St., Beitou, Taipei, Taiwan (China); Department of Education and Research, Taipei City Hospital, Taipei, Taiwan (China); Wang, Pei-Wei [Department of Pediatrics, Taipei City Hospital, Taipei, Taiwan (China); Huang, Li-Wei [Department of OBS and GYN, Taipei City Hospital, Women and Children' s Campus, Taipei, Taiwan (China); Yang, Winnie [Department of Pediatrics, Taipei City Hospital, Taipei, Taiwan (China); Yu, Ching-Jung; Yang, Shang-Han; Chiu, Hsin-Hao [Institute of Environmental and Occupational Health Sciences, National Yang Ming University, No. 155, Sec. 2, Li-Nong St., Beitou, Taipei, Taiwan (China); Chen, Mei-Lien, E-mail: mlchen@ym.edu.tw [Institute of Environmental and Occupational Health Sciences, National Yang Ming University, No. 155, Sec. 2, Li-Nong St., Beitou, Taipei, Taiwan (China)

    2014-10-15

    As the predominant environmental biodegradation product of nonylphenol (NP) ethoxylates and with proven estrogenic effects, NP is formed during the alkylation process of phenols. The purposes of this study were (1) to examine maternal and prenatal exposure to NP in Taiwan, (2) to determine the level of placental protection against NP exposure as well as the level of NP in breast milk, and (3) to assess the potential risk for breastfed newborns exposed to NP through the milk. Thirty pairs of maternal and fetal blood samples, placenta, and breast milk during the 1st and the 3rd months of lactation were collected. External NP exposures of these specimens were then analyzed by using high-performance liquid chromatography coupling with fluorescence detection. Next, the socio-demographics, lifestyle, delivery method, dietary and work history were collected using a questionnaire. In addition, the daily intake of NP from consuming breast milk in the 1st and 3rd months for newborns was studied through deterministic and probabilistic risk assessment methods. The geometric means and geometric standard deviation of NP levels in maternal blood, fetal cord blood, placenta, and breast milk in the 1st and 3rd months were 14.6 (1.7) ng/ml, 18.8 (1.8) ng/ml, 19.8 (1.9) ng/g, 23.5 (3.2) ng/ml, and 57.3 (1.4) ng/ml, respectively. The probabilistic percentiles (50th, 75th, and 95th) of daily intake NP in breast milk were 4.33, 7.79, and 18.39 μg/kg-bw/day in the 1st month, respectively, and were 8.11, 10.78, 16.08 μg/kg-bw/day in the 3rd month, respectively. The probabilistic distributions (5th, 25th, and 50th) of risk for infants aged 1 month old were 0.27, 0.64, and 1.15, respectively, and that for infants aged 3 month old were 0.31, 0.46, and 0.62, respectively. Through repeated exposure from the dietary intake of expectant mothers, fetuses could encounter a high NP exposure level due to transplacental absorption, partitioning between the maternal and fetal compartments. Daily NP

  2. Lewis Acid Coupled Electron Transfer of Metal-Oxygen Intermediates.

    Science.gov (United States)

    Fukuzumi, Shunichi; Ohkubo, Kei; Lee, Yong-Min; Nam, Wonwoo

    2015-12-01

    Redox-inactive metal ions and Brønsted acids that function as Lewis acids play pivotal roles in modulating the redox reactivity of metal-oxygen intermediates, such as metal-oxo and metal-peroxo complexes. The mechanisms of the oxidative CH bond cleavage of toluene derivatives, sulfoxidation of thioanisole derivatives, and epoxidation of styrene derivatives by mononuclear nonheme iron(IV)-oxo complexes in the presence of triflic acid (HOTf) and Sc(OTf)3 have been unified as rate-determining electron transfer coupled with binding of Lewis acids (HOTf and Sc(OTf)3 ) by iron(III)-oxo complexes. All logarithms of the observed second-order rate constants of Lewis acid-promoted oxidative CH bond cleavage, sulfoxidation, and epoxidation reactions of iron(IV)-oxo complexes exhibit remarkably unified correlations with the driving forces of proton-coupled electron transfer (PCET) and metal ion-coupled electron transfer (MCET) in light of the Marcus theory of electron transfer when the differences in the formation constants of precursor complexes were taken into account. The binding of HOTf and Sc(OTf)3 to the metal-oxo moiety has been confirmed for Mn(IV) -oxo complexes. The enhancement of the electron-transfer reactivity of metal-oxo complexes by binding of Lewis acids increases with increasing the Lewis acidity of redox-inactive metal ions. Metal ions can also bind to mononuclear nonheme iron(III)-peroxo complexes, resulting in acceleration of the electron-transfer reduction but deceleration of the electron-transfer oxidation. Such a control on the reactivity of metal-oxygen intermediates by binding of Lewis acids provides valuable insight into the role of Ca(2+) in the oxidation of water to dioxygen by the oxygen-evolving complex in photosystem II. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Placental transfer of metals of coal fly ash into various fetal organs of rat

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, V.K.; Chauhan, S.S.; Srivastava, P.K.; Shukla, R.R.; Kumar, V.; Misra, U.K. (Delhi Univ. (India). Dept. of Biochemistry)

    1990-03-01

    Fly ash (100 mg/kg body weight) was administered intratracheally to 14-day pregnant rats for 6 consecutive days. On day 20 of gestation the translocation of metals present in the fly ash to various maternal and fetal organs was studied. Fly ash administration to pregnant mothers retarded the growth of fetal heart and kidney as determined by their weights. Fly ash instillation increased organ levels of nearly all the metals studied in both mother and fetus. Most of the metals present in coal fly ash were transferred in significant amounts through placenta to several fetal organs. However, the pattern of their distribution into various fetal organs was different for different metals.

  4. Oxygen-transfer performance of a newly designed, very low-volume membrane oxygenator.

    Science.gov (United States)

    Burn, Felice; Ciocan, Sorin; Carmona, Natalia Mendez; Berner, Marion; Sourdon, Joevin; Carrel, Thierry P; Tevaearai Stahel, Hendrik T; Longnus, Sarah L

    2015-09-01

    Oxygenation of blood and other physiological solutions are routinely required in fundamental research for both in vitro and in vivo experimentation. However, very few oxygenators with suitable priming volumes (parallel-oriented microporous polypropylene hollow fibres, placed inside a hollow shell with a lateral-luer outlet, and sealed at both extremities. With this design, perfusate is delivered via the core-tube to the centre of the mini-oxygenator, and exits via the luer port. A series of mini-oxygenators were constructed and tested in an in vitro perfusion circuit by monitoring oxygen transfer using modified Krebs-Henseleit buffer or whole porcine blood. Effects of perfusion pressure and temperature over flows of 5-60 ml × min(-1) were assessed. Twelve mini-oxygenators with a mean priming volume of 1.5 ± 0.3 ml were evaluated. With buffer, oxygen transfer reached a maximum of 14.8 ± 1.0 ml O2 × l(-1) (pO2: 450 ± 32 mmHg) at perfusate flow rates of 5 ml × min(-1) and decreased with an increase in perfusate flow to 7.8 ± 0.7 ml ml O2 × l(-1) (pO2: 219 ± 24 mmHg) at 60 ml × min(-1). Similarly, with blood perfusate, oxygen transfer also decreased as perfusate flow increased, ranging from 33 ± 5 ml O2 × l(-1) at 5 ml × min(-1) to 11 ± 2 ml O2 × l(-1) at 60 ml × min(-1). Furthermore, oxygen transfer capacity remained stable with blood perfusion over a period of at least 2 h. We have developed a new miniaturized membrane oxygenator with an ultra-low priming volume (circuits, such as small animal extracorporeal circulation and ex vivo organ perfusion. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  5. Placental Aromatase Is Deficient in Placental Ischemia and Preeclampsia.

    Directory of Open Access Journals (Sweden)

    Alejandra Perez-Sepulveda

    Full Text Available Preeclampsia is a maternal hypertensive disorder with uncertain etiology and a leading cause of maternal and fetal mortality worldwide, causing nearly 40% of premature births delivered before 35 weeks of gestation. The first stage of preeclampsia is characterized by reduction of utero-placental blood flow which is reflected in high blood pressure and proteinuria during the second half of pregnancy. In human placenta androgens derived from the maternal and fetal adrenal glands are converted into estrogens by the enzymatic action of placental aromatase. This implies that alterations in placental steroidogenesis and, subsequently, in the functionality or bioavailability of placental aromatase may be mechanistically involved in the pathophysiology of PE.Serum samples were collected at 32-36 weeks of gestation and placenta biopsies were collected at time of delivery from PE patients (n = 16 and pregnant controls (n = 32. The effect of oxygen tension on placental cells was assessed by incubation JEG-3 cells under 1% and 8% O2 for different time periods, Timed-mated, pregnant New Zealand white rabbits (n = 6 were used to establish an in vivo model of placental ischemia (achieved by ligature of uteroplacental vessels. Aromatase content and estrogens and androgens concentrations were measured.The protein and mRNA content of placental aromatase significantly diminished in placentae obtained from preeclamptic patients compared to controls. Similarly, the circulating concentrations of 17-β-estradiol/testosterone and estrone/androstenedione were reduced in preeclamptic patients vs. controls. These data are consistent with a concomitant decrease in aromatase activity. Aromatase content was reduced in response to low oxygen tension in the choriocarcinoma JEG-3 cell line and in rabbit placentae in response to partial ligation of uterine spiral arteries, suggesting that reduced placental aromatase activity in preeclamptic patients may be associated with chronic

  6. Regional placental blood oxygen level dependent (BOLD) changes with gestational age in normally developing pregnancies using long duration R2* mapping in utero

    Science.gov (United States)

    Dighe, Manjiri; Kim, Yun Jung; Seshamani, Sharmishtaa; Blazejewska, Ania I.; Mckown, Susan; Caucutt, Jason; Gatenby, Christopher; Studholme, Colin

    2016-03-01

    The aim of this study was to examine the use of R2* mapping in maternal and fetal sub-regions of the placenta with the aim of providing a reference for blood oxygenation levels during normative development. There have been a number of MR relaxation studies of placental tissues in-utero, but none have reported R2* value changes with age, or examined differences in sub-regions of the placenta. Here specialized long-duration Multi-frame R2* imaging was used to create a stable estimate for R2* values in different placental regions in healthy pregnant volunteers not imaged for clinical reasons. 27 subjects were recruited and scanned up to 3 times during their pregnancy. A multi-slice dual echo EPI based BOLD acquisition was employed and repeated between 90 and 150 times over 3 to 5 minutes to provide a high accuracy estimate of the R2* signal level. Acquisitions were also repeated in 13 cases within a visit to evaluate reproducibility of the method in a given subject. Experimental results showed R2* measurements were highly repeatable within a visit with standard deviation of (0.76). Plots of all visits against gestational age indicated clear correlations showing decreases in R2* with age. This increase was consistent was also consistent over time in multiple visits of the same volunteer during their pregnancy. Maternal and fetal regional changes with gestational age followed the same trend with increase in R2* over the gestational age.

  7. Bidirectional placental transfer of Bisphenol A and its main metabolite, Bisphenol A-Glucuronide, in the isolated perfused human placenta.

    Science.gov (United States)

    Corbel, T; Gayrard, V; Puel, S; Lacroix, M Z; Berrebi, A; Gil, S; Viguié, C; Toutain, P-L; Picard-Hagen, N

    2014-08-01

    The widespread human exposure to Bisphenol A (BPA), an endocrine disruptor interfering with developmental processes, raises the question of the risk for human health of BPA fetal exposure. In humans, highly variable BPA concentrations have been reported in the feto-placental compartment. However the human fetal exposure to BPA still remains unclear. The aim of the study was to characterize placental exchanges of BPA and its main metabolite, Bisphenol A-Glucuronide (BPA-G) using the non-recirculating dual human placental perfusion. This high placental bidirectional permeability to the lipid soluble BPA strongly suggests a transport by passive diffusion in both materno-to-fetal and feto-to-maternal direction, leading to a calculated ratio between fetal and maternal free BPA concentrations of about 1. In contrast, BPA-G has limited placental permeability, particularly in the materno-to-fetal direction. Thus the fetal exposure to BPA conjugates could be explained mainly by its limited capacity to extrude BPA-G.

  8. The evolution of epitheliochorial placentation.

    Science.gov (United States)

    Carter, Anthony M; Enders, Allen C

    2013-01-01

    Epitheliochorial placentation is a derived condition and has evolved separately in strepsirrhine primates and laurasiatherians (pangolins, whales, and hoofed mammals). Usually it is associated with a long gestation period, small litters, and precocial young. Oxygen transfer is facilitated by indenting of the uterine and trophoblast epithelia by maternal and fetal capillaries, respectively. Histotrophic nutrition is important, and adaptations include areolas and hemophagous regions. In pigs and horses, for example, iron is transported as uteroferrin secreted from the uterine glands and taken up by areolas. In the horse, invasive trophoblast cells form cups within the endometrium that are the source of equine chorionic gonadotropin. In ruminants, binucleate trophoblast cells fuse with uterine epithelial cells to form trinucleate cells or plaques that secrete pregnancy hormones. There is evidence of immunosuppression in connection with these more invasive types of trophoblasts. The epitheliochorial condition may be advantageous for long pregnancies in large animals.

  9. Influence of pluronic F68 on oxygen mass transfer.

    Science.gov (United States)

    Sieblist, Christian; Jenzsch, Marco; Pohlscheidt, Michael

    2013-01-01

    Pluronic F68 is one of the most used shear protecting additives in cell culture cultivations. It is well known from literature that such surface-active surfactants lower the surface tension at the gas-liquid interface, which influences the mass transfer. In this study, the effect of Pluronic F68 on oxygen mass transfer in aqueous solutions was examined. Therefore, the gassing in/gassing out method and bubble size measurements were used. At low concentrations of 0.02 g/L, a 50% reduction on mass transfer was observed for all tested spargers and working conditions. An explanation of the observed effects by means of Higbie's penetration or Dankwerts surface renewal theory was applied. It could be demonstrated that the suppressed movement of the bubble surface layer is the main cause for the significant drop down of the kL a-values. For Pluronic F68 concentrations above 0.1 g/L, it was observed that it comes to changes in bubble appearance and bubble size strongly dependent on the sparger type. By using the bubble size measurement data, it could be shown that only small changes in mass transfer coefficient (kL ) take place above the critical micelle concentration. Further changes on overall mass transfer at higher Pluronic F68 concentrations are mainly based on increasing of gas holdup and, more importantly, by increasing of the surface area available for mass transfer. © 2013 American Institute of Chemical Engineers.

  10. Catalytic electron-transfer oxygenation of substrates with water as an oxygen source using manganese porphyrins.

    Science.gov (United States)

    Fukuzumi, Shunichi; Mizuno, Takuya; Ojiri, Tetsuya

    2012-12-03

    Manganese(V)-oxo-porphyrins are produced by the electron-transfer oxidation of manganese-porphyrins with tris(2,2'-bipyridine)ruthenium(III) ([Ru(bpy)(3)](3+); 2 equiv) in acetonitrile (CH(3)CN) containing water. The rate constants of the electron-transfer oxidation of manganese-porphyrins have been determined and evaluated in light of the Marcus theory of electron transfer. Addition of [Ru(bpy)(3)](3+) to a solution of olefins (styrene and cyclohexene) in CH(3)CN containing water in the presence of a catalytic amount of manganese-porphyrins afforded epoxides, diols, and aldehydes efficiently. Epoxides were converted to the corresponding diols by hydrolysis, and were further oxidized to the corresponding aldehydes. The turnover numbers vary significantly depending on the type of manganese-porphyrin used owing to the difference in their oxidation potentials and the steric bulkiness of the ligand. Ethylbenzene was also oxidized to 1-phenylethanol using manganese-porphyrins as electron-transfer catalysts. The oxygen source in the substrate oxygenation was confirmed to be water by using (18)O-labeled water. The rate constant of the reaction of the manganese(V)-oxo species with cyclohexene was determined directly under single-turnover conditions by monitoring the increase in absorbance attributable to the manganese(III) species produced in the reaction with cyclohexene. It has been shown that the rate-determining step in the catalytic electron-transfer oxygenation of cyclohexene is electron transfer from [Ru(bpy)(3)](3+) to the manganese-porphyrins.

  11. Mammalian Placentation

    DEFF Research Database (Denmark)

    Carter, Anthony Michael; Mess, A. M.

    2014-01-01

    This guide to animal models of human placentation assesses the strengths and weaknesses of species in common use. We argue that structural differences from human placenta, though important in some contexts, are less of a drawback than differences in reproductive strategy. Many laboratory rodents...... to consider animal models with longer gestations and well-developed neonates. Placentation in different orders of mammal is surveyed and their proximity to humans described in an evolutionary context. Animal models are then compared with the human in terms of the functional anatomy, physiology, and immunology...... have brief gestations resulting in the birth of poorly developed young. They can provide useful insights on placental development and function relevant to early human pregnancy. However, to model the events of a 9-month gestation, which imposes added requirements on the placenta, it is necessary...

  12. Evolution of the placenta during the early radiation of placental mammals.

    Science.gov (United States)

    Mess, Andrea; Carter, Anthony M

    2007-12-01

    The chorioallantoic placenta is an organ of gaseous exchange that exhibits a high degree of structural diversity. One factor determining oxygen transfer across the placenta, the diffusion distance, is in part dependent on the number of cell layers separating maternal from fetal blood. This interhaemal barrier occurs in three principal variants. The focus of this review is on determining how the barrier evolved in placental mammals. The analysis was based on current knowledge of placental structure, as far as possible using ultrastructural data, and on current views about the evolution of placental mammals, derived from molecular phylogenetics. We show that epitheliochorial placentation, the least invasive type, is a derived state and discuss factors that may have determined its evolution with reference to conflict theory, as applied to the allocation of resources between mother and fetus. It is not yet possible to determine which of the two more invasive types of placentation occurred in the last common ancestor of crown placentals. Depending on tree topology and taxon sampling, the result achieved is either endotheliochorial, haemochorial or unresolved. Finally we discuss other factors important to placental gas exchange and point to physiological variables that might become amenable to phylogenetic analysis.

  13. Computer-assisted numerical analysis for oxygen and carbon dioxide mass transfer in blood oxygenators.

    Science.gov (United States)

    Turri, Fabio; Yanagihara, Jurandir Itizo

    2011-06-01

    A two-dimensional numeric simulator is developed to predict the nonlinear, convective-reactive, oxygen mass exchange in a cross-flow hollow fiber blood oxygenator. The numeric simulator also calculates the carbon dioxide mass exchange, as hemoglobin affinity to oxygen is affected by the local pH value, which depends mostly on the local carbon dioxide content in blood. Blood pH calculation inside the oxygenator is made by the simultaneous solution of an equation that takes into account the blood buffering capacity and the classical Henderson-Hasselbach equation. The modeling of the mass transfer conductance in the blood comprises a global factor, which is a function of the Reynolds number, and a local factor, which takes into account the amount of oxygen reacted to hemoglobin. The simulator is calibrated against experimental data for an in-line fiber bundle. The results are: (i) the calibration process allows the precise determination of the mass transfer conductance for both oxygen and carbon dioxide; (ii) very alkaline pH values occur in the blood path at the gas inlet side of the fiber bundle; (iii) the parametric analysis of the effect of the blood base excess (BE) shows that (.)V(CO₂) is similar in the case of blood metabolic alkalosis, metabolic acidosis, or normal BE, for a similar blood inlet P(CO₂), although the condition of metabolic alkalosis is the worst case, as the pH in the vicinity of the gas inlet is the most alkaline; (iv) the parametric analysis of the effect of the gas flow to blood flow ratio (QG/QB) shows that (.)V(CO₂) variation with the gas flow is almost linear up to QG/QB = 2.0. (.)V(O₂) is not affected by the gas flow as it was observed that by increasing the gas flow up to eight times, the (.)V(O₂) grows only 1%. The mass exchange of carbon dioxide uses the full length of the hollow-fiber only if Q(G) /Q(B)> 2.0, as it was observed that only in this condition does the local variation of pH and blood P(CO₂) comprise the whole

  14. Revisiting direct electron transfer in nanostructured carbon laccase oxygen cathodes.

    Science.gov (United States)

    Adam, Catherine; Scodeller, Pablo; Grattieri, Matteo; Villalba, Matías; Calvo, Ernesto J

    2016-06-01

    The biocatalytic electroreduction of oxygen has been studied on large surface area graphite and Vulcan® carbon electrodes with adsorbed Trametes trogii laccase. The electrokinetics of the O2 reduction reaction (ORR) was studied at different electrode potentials, O2 partial pressures and concentrations of hydrogen peroxide. Even though the overpotential at 0.25 mA·cm(-2) for the ORR at T1Cu of the adsorbed laccase on carbon is 0.8 V lower than for Pt of similar geometric area, the rate of the reaction and thus the operative current density is limited by the enzyme reaction rate at the T2/T3 cluster site for the adsorbed enzyme. The transition potential for the rate determining step from the direct electron transfer (DET) to the enzyme reaction shifts to higher potentials at higher oxygen partial pressure. Hydrogen peroxide produced by the ORR on bare carbon support participates in an inhibition mechanism, with uncompetitive predominance at high H2O2 concentration, non-competitive contribution can be detected at low inhibitor concentration.

  15. Placental economies

    DEFF Research Database (Denmark)

    Lee, Jieun

    2016-01-01

    and sustained through the relations and practices of care that animate the placenta in different forms. On the basis of an ethnographic fieldwork conducted in Korea, this article focuses on two different forms of care (lab workers’ care of cells, and pregnant women’s care of fetuses) that enable the (re......Thinking with the vital materiality of placentas as it is evinced in a placental stem cell research lab in Korea, this article explores the relations and practices of care that are essential to the circulation of biological matters as infrastructure of tissue economies. I attend to the flows...... of care that sustain tissue economies with the notion of ‘placental economies’. Shifting attention from donor subjects and tissue objects to practices and relations of care as an infrastructure for the circulation of tissues, I explore how the vitality of biological matters is an achievement made...

  16. Mammalian Placentation

    DEFF Research Database (Denmark)

    Carter, Anthony Michael; Mess, A. M.

    2014-01-01

    This guide to animal models of human placentation assesses the strengths and weaknesses of species in common use. We argue that structural differences from human placenta, though important in some contexts, are less of a drawback than differences in reproductive strategy. Many laboratory rodents...... to consider animal models with longer gestations and well-developed neonates. Placentation in different orders of mammal is surveyed and their proximity to humans described in an evolutionary context. Animal models are then compared with the human in terms of the functional anatomy, physiology, and immunology...... of the placenta. This information is collated both to assess common animal models such as mouse, sheep, and primates and to introduce some alternatives that we consider worthy of attention....

  17. Placental transfer of the polybrominated diphenyl ethers BDE-47, BDE-99 and BDE-209 in a human placenta perfusion system: an experimental study

    DEFF Research Database (Denmark)

    Frederiksen, Marie; Vorkamp, Katrin; Mathiesen, Line

    2010-01-01

    BACKGROUND: Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants in consumer products. PBDEs may affect thyroid hormone homeostasis, which can result in irreversible damage of cognitive performance, motor skills and altered behaviour. Thus, in utero exposure is of very...... high concern due to critical windows in fetal development. METHODS: A human ex vivo placenta perfusion system was used to study the kinetics and extent of the placental transfer of BDE-47, BDE-99 and BDE-209 during four-hour perfusions. The PBDEs were added to the maternal circulation and monitored....... CONCLUSION: The transport of BDE-47 and BDE-99 indicates in utero exposure to these congeners. Although the transport of BDE-209 was limited, however, possible metabolic debromination may lead to products which are both more toxic and transportable. Our study demonstrates fetal exposure to PBDEs, which...

  18. PLACENTAL PATHOLOGY IN INTRA UTERINE GROWTH RETARDATION

    Directory of Open Access Journals (Sweden)

    Vijaya Sheela

    2015-04-01

    Full Text Available INTRODUCTION: The placental development is an essential step in developing effective strategies or the prediction of various maternal and fetal medical and developmental problems . Oxygen transfer and nutrients to the fetus will be actively regulated by the placenta . AIM AND OBJECTIVE: To study morphological changes of placenta in Intrauterine growth Retardation and to correlate morphological changes of placenta with fetal outcome . MATERIALS AND METHODS: Placental tissue samples were obtained from 50 pregnancies complicated by IUGR and 50 normal uncomplicated pregnancies with gestational age between 28 to 42 weeks attending King George hospital Visakhapatnam . INCLUSIVE CRITERIA : An IUGR fetuses whose estimated fetal weight less than those in 10 th percentile are included in the study . Birth weight percentiles were determined by previously published normal curves . EXCLUSIVE CRITERIA: fetuses with known syndromes , chromosomal anomalies and twins . For all patients included in the data set gestational age was estimated from the last menstrual period or early ultra - sonogram before the 12 th week of gestation . The final data set was composed of 50pregnancies complicated by IUGR and APGAR scores . Because preeclampsia is an important maternal factor associated with IUGR , these cases were further divided into t wo subgroups according to presence of hypertension . Samples were taken both from vaginal deliveries and caesarean sections . All the placentas were examined by pathologists . The placentas were weighed . For each case one or two samples from the umbilical cor ds , extra placental membrane , and parenchyma were taken . Gross pathological findings were confirmed by histology . Histological data included are ischemic necrosis , decidual vascularity , acute chorioamni oni tis , fibrinoid necrosis and choriangiosis . Appropriate statistical parameters were used . Chi - square test was conducted to compare placental pathological changes

  19. Theoretical analysis and experimental study of oxygen transfer under regular and non-breaking waves

    Institute of Scientific and Technical Information of China (English)

    尹则高; 梁丙臣; 王乐

    2013-01-01

    The dissolved oxygen concentration is an important index of water quality, and the atmosphere is one of the important sources of the dissolved oxygen. In this paper, the mass conservation law and the dimensional analysis method are employed to study the oxygen transfer under regular and non-breaking waves, and a unified oxygen transfer coefficient equation is obtained with consi-deration of the effect of kinetic energy and wave period. An oxygen transfer experiment for the intermediate depth water wave is per-formed to measure the wave parameters and the dissolved oxygen concentration. The experimental data and the least squares method are used to determine the constant in the oxygen transfer coefficient equation. The experimental data and the previous reported data are also used to further validate the oxygen transfer coefficient, and the agreement is satisfactory. The unified equation shows that the oxygen transfer coefficient increases with the increase of a parameter coupled with the wave height and the wave length, but it de-creases with the increase of the wave period, which has a much greater influence on the oxygen transfer coefficient than the coupled parameter.

  20. Polyoxometalate-mediated electron transfer-oxygen transfer oxidation of cellulose and hemicellulose to synthesis gas.

    Science.gov (United States)

    Sarma, Bidyut Bikash; Neumann, Ronny

    2014-08-01

    Terrestrial plants contain ~70% hemicellulose and cellulose that are a significant renewable bioresource with potential as an alternative to petroleum feedstock for carbon-based fuels. The efficient and selective deconstruction of carbohydrates to their basic components, carbon monoxide and hydrogen, so called synthesis gas, is an important key step towards the realization of this potential, because the formation of liquid hydrocarbon fuels from synthesis gas are known technologies. Here we show that by using a polyoxometalate as an electron transfer-oxygen transfer catalyst, carbon monoxide is formed by cleavage of all the carbon-carbon bonds through dehydration of initially formed formic acid. In this oxidation-reduction reaction, the hydrogen atoms are stored on the polyoxometalate as protons and electrons, and can be electrochemically released from the polyoxometalate as hydrogen. Together, synthesis gas is formed. In a hydrogen economy scenario, this method can also be used to convert carbon monoxide to hydrogen.

  1. Certolizumab pegol does not bind the neonatal Fc receptor (FcRn): Consequences for FcRn-mediated in vitro transcytosis and ex vivo human placental transfer.

    Science.gov (United States)

    Porter, Charlene; Armstrong-Fisher, Sylvia; Kopotsha, Tim; Smith, Bryan; Baker, Terry; Kevorkian, Lara; Nesbitt, Andrew

    2016-08-01

    Antibodies to tumor necrosis factor (anti-TNF) are used to treat inflammatory diseases, which often affect women of childbearing age. The active transfer of these antibodies across the placenta by binding of the Fc-region to the neonatal Fc receptor (FcRn) may result in adverse fetal or neonatal effects. In contrast to other anti-TNFs, certolizumab pegol lacks an Fc-region. The objective of this study was to determine whether the structure of certolizumab pegol limits active placental transfer. Binding affinities of certolizumab pegol, infliximab, adalimumab and etanercept to human FcRn and FcRn-mediated transcytosis were determined using in vitro assays. Human placentas were perfused ex vivo to measure transfer of certolizumab pegol and positive control anti-D IgG from the maternal to fetal circulation. FcRn binding affinity (KD) was 132nM, 225nM and 1500nM for infliximab, adalimumab and etanercept, respectively. There was no measurable certolizumab pegol binding affinity, similar to that of the negative control. FcRn-mediated transcytosis across a cell layer (mean±SD; n=3) was 249.6±25.0 (infliximab), 159.0±20.2 (adalimumab) and 81.3±13.1ng/mL (etanercept). Certolizumab pegol transcytosis (3.2±3.4ng/mL) was less than the negative control antibody (5.9±4.6ng/mL). No measurable transfer of certolizumab pegol from the maternal to the fetal circulation was observed in 5 out of 6 placentas that demonstrated positive-control IgG transport in the ex vivo perfusion model. Together these results support the hypothesis that the unique structure of certolizumab pegol limits its transfer through the placenta to the fetus and may be responsible for previously reported differences in transfer of other anti-TNFs from mother to fetus.

  2. Oxygen-Reducing Biocathodes Operating with Passive Oxygen Transfer in Microbial Fuel Cells

    KAUST Repository

    Xia, Xue

    2013-02-19

    Oxygen-reducing biocathodes previously developed for microbial fuel cells (MFCs) have required energy-intensive aeration of the catholyte. To avoid the need for aeration, the ability of biocathodes to function with passive oxygen transfer was examined here using air cathode MFCs. Two-chamber, air cathode MFCs with biocathodes produced a maximum power density of 554 ± 0 mW/m 2, which was comparable to that obtained with a Pt cathode (576 ± 16 mW/m2), and 38 times higher than that produced without a catalyst (14 ± 3 mW/m2). The maximum current density with biocathodes in this air-cathode MFC was 1.0 A/m2, compared to 0.49 A/m2 originally produced in a two-chamber MFC with an aqueous cathode (with cathode chamber aeration). Single-chamber, air-cathode MFCs with the same biocathodes initially produced higher voltages than those with Pt cathodes, but after several cycles the catalytic activity of the biocathodes was lost. This change in cathode performance resulted from direct exposure of the cathodes to solutions containing high concentrations of organic matter in the single-chamber configuration. Biocathode performance was not impaired in two-chamber designs where the cathode was kept separated from the anode solution. These results demonstrate that direct-air biocathodes can work very well, but only under conditions that minimize heterotrophic growth of microorganisms on the cathodes. © 2013 American Chemical Society.

  3. Determinants of oxygen and carbon dioxide transfer during extracorporeal membrane oxygenation in an experimental model of multiple organ dysfunction syndrome.

    Science.gov (United States)

    Park, Marcelo; Costa, Eduardo Leite Vieira; Maciel, Alexandre Toledo; Silva, Débora Prudêncio E; Friedrich, Natalia; Barbosa, Edzangela Vasconcelos Santos; Hirota, Adriana Sayuri; Schettino, Guilherme; Azevedo, Luciano Cesar Pontes

    2013-01-01

    Extracorporeal membrane oxygenation (ECMO) has gained renewed interest in the treatment of respiratory failure since the advent of the modern polymethylpentene membranes. Limited information exists, however, on the performance of these membranes in terms of gas transfers during multiple organ failure (MOF). We investigated determinants of oxygen and carbon dioxide transfer as well as biochemical alterations after the circulation of blood through the circuit in a pig model under ECMO support before and after induction of MOF. A predefined sequence of blood and sweep flows was tested before and after the induction of MOF with fecal peritonitis and saline lavage lung injury. In the multivariate analysis, oxygen transfer had a positive association with blood flow (slope = 66, PMOF from 7.19[6.92,7.32] to 7.41[7.13,7.5] (PMOF from 59 [47,91] to 34 [28,45] mmHg (P<0.001). In conclusion, both oxygen and carbon dioxide transfers were significantly determined by blood flow. Oxygen transfer was modulated by the pre-membrane SatO(2) and CO(2), while carbon dioxide transfer was affected by the gas flow, pre-membrane CO(2) and hemoglobin.

  4. Hypoxia and the anticoagulants dalteparin and acetylsalicylic acid affect human placental amino acid transport.

    Directory of Open Access Journals (Sweden)

    Marc-Jens Kleppa

    Full Text Available BACKGROUND: Anticoagulants, e.g. low-molecular weight heparins (LMWHs and acetylsalicylic acid (ASA are prescribed to women at risk for pregnancy complications that are associated with impaired placentation and placental hypoxia. Beyond their role as anticoagulants these compounds exhibit direct effects on trophoblast but their impact on placental function is unknown. The amino acid transport systems A and L, which preferably transfer essential amino acids, are well-described models to study placental nutrient transport. We aimed to examine the effect of hypoxia, LMWHs and ASA on the activity of the placental amino acid transport systems A and L and associated signalling mechanisms. METHODS: The uptake of C14-MeAIB (system A or H3-leucin (system L was investigated after incubation of primary villous fragments isolated from term placentas. Villous tissue was incubated at 2% O2 (hypoxia, 8% O2 and standard culture conditions (21% O2 or at 2% O2 and 21% O2 with dalteparin or ASA. Activation of the JAK/STAT or mTOR signalling pathways was determined by Western analysis of total and phosphorylated STAT3 or Raptor. RESULTS: Hypoxia decreased system A mediated MeAIB uptake and increased system L mediated leucine uptake compared to standard culture conditions (21% O2. This was accompanied by an impairment of STAT3 and a stimulation of Raptor signalling. System L activity increased at 8% O2. Dalteparin treatment reduced system A and system L activity under normoxic conditions and ASA (1 mM decreased system A and L transporter activity under normoxic and hypoxic conditions. CONCLUSIONS: Our data underline the dependency of placental function on oxygen supply. LMWHs and ASA are not able to reverse the effects of hypoxia on placental amino acid transport. These findings and the uncovering of the signalling mechanisms in more detail will help to understand the impact of LMWHs and ASA on placental function and fetal growth.

  5. Oxygen transfer rates and requirements in oxidative biocatalysis

    DEFF Research Database (Denmark)

    Pedersen, Asbjørn Toftgaard; Rehn, Gustav; Woodley, John M.

    2015-01-01

    Biocatalytic oxidation reactions offer several important benefits such as regio- and stereoselectivity, avoiding the use of toxic metal based catalysts and replacing oxidizing reagents by allowing the use of oxygen. In this contribution the oxygen requirements are analysed for different process s...... without oxygen supply being limiting. Also, membrane contactors can provide a feasible oxygen supply method when bubble-less aeration is desired. However, in order to support high productivity the oxygen flux using air may be insufficient, thus requiring the use of oxygen....... scenarios, considering different biocatalyst formats and variation of the desired productivity. Also, the applicability of two different oxygen supply methods (bubbling and membrane aeration) is considered. The results indicate that growing cells could be used to reach productivities up to 3.5 g L-1h-1...

  6. The placental exposome: Placental determinants of fetal adiposity and postnatal body composition

    NARCIS (Netherlands)

    R.M. Lewis (R.); H. Demmelmair (Hans); R. Gaillard (Romy); N. Godfrey; S. Hauguel-De Mouzon (S.); B. Huppertz (B.); E. Larque (E.); R. Saffery (R.); M.E. Symonds (M.); G. Desoye (G.)

    2013-01-01

    textabstractOffspring of obese and diabetic mothers are at increased risk of being born with excess adiposity as a consequence of their intrauterine environment. Excessive fetal fat accretion reflects additional placental nutrient transfer, suggesting an effect of the maternal environment on placent

  7. The placental exposome: Placental determinants of fetal adiposity and postnatal body composition

    NARCIS (Netherlands)

    R.M. Lewis (R.); H. Demmelmair (Hans); R. Gaillard (Romy); N. Godfrey; S. Hauguel-De Mouzon (S.); B. Huppertz (B.); E. Larque (E.); R. Saffery (R.); M.E. Symonds (M.); G. Desoye (G.)

    2013-01-01

    textabstractOffspring of obese and diabetic mothers are at increased risk of being born with excess adiposity as a consequence of their intrauterine environment. Excessive fetal fat accretion reflects additional placental nutrient transfer, suggesting an effect of the maternal environment on placent

  8. Effect of oxygen transfer rate on cellulases production in stirred tank and internal-loop airlift bioreactors

    OpenAIRE

    Michelin, Michele; Mota,André; Silva,Daniel Pereira da; A.A. Vicente; Teixeira, J. A; Polizeli, Maria de Lourdes T. M.

    2013-01-01

    In an aerobic process, such as enzymes production by fungi, the oxygen supply into fermentation medium is an important factor in order to achieve good productivities. Oxygen has an important role in metabolism and microorganism growth, being of extreme importance the control of both the dissolved oxygen transfer rate into the bioreactor and the oxygen consumption by the microorganism [1,2]. Dissolved oxygen transfer rate can be analyzed and described by means of the mass transfer coefficient,...

  9. Measurement of oxygen transfer from air into organic solvents

    DEFF Research Database (Denmark)

    Ramesh, Hemalata; Mayr, Torsten; Hobisch, Mathias;

    2016-01-01

    For the first time, we demonstrate on-line oxygen measurements in non-aqueous media using a novel optical sensor. The sensor was used to measure oxygen concentration in various organic solvents including toluene, THF, isooctane, DMF, heptane and hexane (which have all been shown suitable for several biological...

  10. Oxygen transfer in marsh-pond-marsh constructed wetlands treating swine wastewater.

    Science.gov (United States)

    Ro, Kyoung S; Hunt, Patrick G; Johnson, Melvin H; Matheny, Terry A; Forbes, Dean; Reddy, Gudigopuram B

    2010-01-01

    Oxygen transfer efficiencies of various components of the marsh-pond-marsh (M-P-M) and marsh-floating bed-marsh (M-FB-M) wetlands treating swine wastewater were determined by performing oxygen mass balance around the wetlands. Biological oxygen demand (BOD) and total nitrogen (TN) loading and escaping rates from each wetland were used to calculate carbonaceous and nitrogenous oxygen demands. Ammonia emissions were measured using a wind tunnel. Oxygen transfer efficiencies of the aerated ponds were estimated by conducting the ASCE standard oxygen transfer test in a tank using the same aeration device. Covering pond water surface with the floating bed slightly decreased oxygen transfer efficiency. The diffused membrane aeration (26.7 kg O2 ha-1 d-1) of M-P-M was surprisingly not as effective as plant aeration in the marsh (38.9 to 42.0 kg O2 ha-1 d-1). This unusually low oxygen transfer efficiency of the diffused aeration was attributed to its low submergence depth of 0.8 m compared to typical depth of 4.5 m. The wetlands consisting entirely of marsh removed similar amounts of C and N without investing additional equipment and energy costs of aerating ponds in the middle of wetlands.

  11. Effects of Oxygen Transfer Limitation and Kinetic Control on Biomimetic Catalytic Oxidation of Toluene

    Institute of Scientific and Technical Information of China (English)

    罗伟平; 刘大为; 孙俊; 邓伟; 盛文兵; 刘强; 郭灿城

    2014-01-01

    Under oxygen transfer limitation and kinetic control, liquid-phase catalytic oxidation of toluene over metalloporphyrin was studied. An improved technique of measuring dissolved oxygen levels for gas-liquid reaction at the elevated temperature and pressure was used to take the sequential data in the oxidation of toluene catalyzed by metalloporphyrin. By this technique the corresponding control step of toluene oxidation could be obtained by varying reaction conditions. When the partial pressure of oxygen in the feed is lower than or equal to 0.070 MPa at 463 K, the oxidation of toluene would be controlled by oxygen transfer, otherwise the reaction would be controlled by kinetics. The effects of both oxygen transfer and kinetic control on the toluene conversion and the selectivity of benzaldehyde and benzyl alcohol in biomimetic catalytic oxidation of toluene were systematically investigated. Three conclusions have been made from the experimental results. Firstly, under the oxygen transfer limitation the toluene conversion is lower than that under kinetic control at the same oxidation conditions. Secondly, under the oxygen transfer limitation the total selectivity of benzaldehyde and benzyl alcohol is lower than that under kinetic control with the same conversion of toluene. Finally, under the kinetics control the oxidation rate of toluene is zero-order with respect to oxygen. The experimental results are identical with the biomimetic catalytic mechanism of toluene oxidation over metalloporphyrins.

  12. Fluorobenzo[a]pyrenes as probes of the mechanism of cytochrome P450-catalyzed oxygen transfer in aromatic oxygenations

    NARCIS (Netherlands)

    Mulder, P.P.J.; Devanesan, P.; Alem, van K.; Lodder, G.; Rogan, E.G.; Cavalieri, E.L.

    2003-01-01

    Fluoro substitution of benzo[a]pyrene (BP) has been very useful in determining the mechanism of cytochrome P450-catalyzed oxygen transfer in the formation of 6-hydroxyBP (6-OHBP) and its resulting BP 1,6-, 3,6-, and 6,12-diones. We report here the metabolism of 1-FBP and 3-FBP, and PM3 calculations

  13. Oxygen transfer rates and requirements in oxidative biocatalysis

    DEFF Research Database (Denmark)

    Pedersen, Asbjørn Toftgaard; Rehn, Gustav; Woodley, John

    different oxygen supply methods (bubbling and membrane aeration) investigated. Hollow fibre membrane contactors present an interesting alternative for reactor aeration, creating large specific areas (area/volume) of the gas/liquid interface. The modular design of membrane contactors, scaling...

  14. Estimation of placental and lactational transfer and tissue distribution of atrazine and its main metabolites in rodent dams, fetuses, and neonates with physiologically based pharmacokinetic modeling

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Zhoumeng [Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602 (United States); Interdisciplinary Toxicology Program, University of Georgia, Athens, GA 30602 (United States); Fisher, Jeffrey W. [Division of Biochemical Toxicology, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079 (United States); Wang, Ran [Center for Environmental Health Sciences, Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762 (United States); Institute of Food Safety, Jiangsu Academy of Agricultural Sciences, Nanjing 210014 (China); Ross, Matthew K. [Center for Environmental Health Sciences, Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762 (United States); Filipov, Nikolay M., E-mail: filipov@uga.edu [Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602 (United States); Interdisciplinary Toxicology Program, University of Georgia, Athens, GA 30602 (United States)

    2013-11-15

    Atrazine (ATR) is a widely used chlorotriazine herbicide, a ubiquitous environmental contaminant, and a potential developmental toxicant. To quantitatively evaluate placental/lactational transfer and fetal/neonatal tissue dosimetry of ATR and its major metabolites, physiologically based pharmacokinetic models were developed for rat dams, fetuses and neonates. These models were calibrated using pharmacokinetic data from rat dams repeatedly exposed (oral gavage; 5 mg/kg) to ATR followed by model evaluation against other available rat data. Model simulations corresponded well to the majority of available experimental data and suggest that: (1) the fetus is exposed to both ATR and its major metabolite didealkylatrazine (DACT) at levels similar to maternal plasma levels, (2) the neonate is exposed mostly to DACT at levels two-thirds lower than maternal plasma or fetal levels, while lactational exposure to ATR is minimal, and (3) gestational carryover of DACT greatly affects its neonatal dosimetry up until mid-lactation. To test the model's cross-species extrapolation capability, a pharmacokinetic study was conducted with pregnant C57BL/6 mice exposed (oral gavage; 5 mg/kg) to ATR from gestational day 12 to 18. By using mouse-specific parameters, the model predictions fitted well with the measured data, including placental ATR/DACT levels. However, fetal concentrations of DACT were overestimated by the model (10-fold). This overestimation suggests that only around 10% of the DACT that reaches the fetus is tissue-bound. These rodent models could be used in fetal/neonatal tissue dosimetry predictions to help design/interpret early life toxicity/pharmacokinetic studies with ATR and as a foundation for scaling to humans. - Highlights: • We developed PBPK models for atrazine in rat dams, fetuses, and neonates. • We conducted pharmacokinetic (PK) study with atrazine in pregnant mice. • Model predictions were in good agreement with experimental rat and mouse PK data

  15. Microparasites and Placental Invasiveness in Eutherian Mammals.

    Directory of Open Access Journals (Sweden)

    Isabella Capellini

    Full Text Available Placental invasiveness-the number of maternal tissue layers separating fetal tissues from maternal blood-is variable across mammalian species. Although this diversity is likely to be functionally important, variation in placental invasiveness remains unexplained. Here we test the hypothesis that increased risk of transplacental transmission of pathogens from the mother to the fetus promotes the evolution of non-invasive placentation, the most likely derived condition in eutherian mammals. Specifically, we predict that non-invasive placentation is associated with increased microparasite species richness relative to more invasive placental types, based on the assumption that higher numbers of microparasites in a population reflects greater risk of transplacental transmission to fetuses. As predicted, higher bacteria species richness is associated with non-invasive placentation. Protozoa species richness, however, shows the opposite pattern. Because invasive placentae facilitate the transfer of maternal antibodies to the fetus, we propose that the ancestral condition of invasive placentation is retained under selection for protection of newborns from higher risk of postnatal protozoan infection. Hence, our findings suggest that a tradeoff exists between protection against bacterial infection prenatally and protozoan infection postnatally. Future studies are needed to investigate how maternal prevalence of infection and the relative pre- versus postnatal risk of fetal infection by different microparasite groups vary among mammalian hosts in relation to placental invasiveness.

  16. Comparison of three commercially available hollow fiber oxygenators : Gas transfer performance and biocompatibility

    NARCIS (Netherlands)

    De Vroege, R; Wagemakers, M; Te Velthuis, H; Bulder, E; Paulus, R; Huybregts, R; Wildevuur, W; Eijsman, L; Van Oeveren, W; Wildevuur, C

    2001-01-01

    The new generation of oxygenators have improved blood flow pathways that enable reduction in priming volume and, thus, hemodilution during cardiopulmonary bypass (CPB). We evaluated three oxygenators and two sizes of venous reservoirs in relation to priming volume, gas transfer, and blood

  17. Liquid films on shake flask walls explain increasing maximum oxygen transfer capacities with elevating viscosity.

    Science.gov (United States)

    Giese, Heiner; Azizan, Amizon; Kümmel, Anne; Liao, Anping; Peter, Cyril P; Fonseca, João A; Hermann, Robert; Duarte, Tiago M; Büchs, Jochen

    2014-02-01

    In biotechnological screening and production, oxygen supply is a crucial parameter. Even though oxygen transfer is well documented for viscous cultivations in stirred tanks, little is known about the gas/liquid oxygen transfer in shake flask cultures that become increasingly viscous during cultivation. Especially the oxygen transfer into the liquid film, adhering on the shake flask wall, has not yet been described for such cultivations. In this study, the oxygen transfer of chemical and microbial model experiments was measured and the suitability of the widely applied film theory of Higbie was studied. With numerical simulations of Fick's law of diffusion, it was demonstrated that Higbie's film theory does not apply for cultivations which occur at viscosities up to 10 mPa s. For the first time, it was experimentally shown that the maximum oxygen transfer capacity OTRmax increases in shake flasks when viscosity is increased from 1 to 10 mPa s, leading to an improved oxygen supply for microorganisms. Additionally, the OTRmax does not significantly undermatch the OTRmax at waterlike viscosities, even at elevated viscosities of up to 80 mPa s. In this range, a shake flask is a somehow self-regulating system with respect to oxygen supply. This is in contrary to stirred tanks, where the oxygen supply is steadily reduced to only 5% at 80 mPa s. Since, the liquid film formation at shake flask walls inherently promotes the oxygen supply at moderate and at elevated viscosities, these results have significant implications for scale-up.

  18. Microbial activity catalyzes oxygen transfer in membrane-aerated nitritating biofilm reactors

    DEFF Research Database (Denmark)

    Pellicer i Nàcher, Carles; Domingo Felez, Carlos; Lackner, Susanne

    2013-01-01

    of the liquid boundary layer developed at the membrane-liquid interface during clean water tests accounted for two thirds of the total mass transfer resistance, suggesting a strong underestimation of the oxygen transfer rates when it is absent (e.g. after biofilm growth). Reactor operation to attain partial...

  19. Oxygen Transfer Model for a Flow-Through Hollow-Fiber Membrane Biofilm Reactor

    DEFF Research Database (Denmark)

    Gilmore, K. R.; Little, J. C.; Smets, Barth F.

    2009-01-01

    A mechanistic oxygen transfer model was developed and applied to a flow-through hollow-fiber membrane-aerated biofilm reactor. Model results are compared to conventional clean water test results as well as performance data obtained when an actively nitrifying biofilm was present on the fibers....... With the biofilm present, oxygen transfer efficiencies between 30 and 55% were calculated from the measured data including the outlet gas oxygen concentration, ammonia consumption stoichiometry, and oxidized nitrogen production stoichiometry, all of which were in reasonable agreement. The mechanistic model...

  20. Rapid hydrogen and oxygen atom transfer by a high-valent nickel-oxygen species

    NARCIS (Netherlands)

    Corona, Teresa; Draksharapu, Apparao; Padamati, Sandeep K; Gamba, Ilaria; Martin-Diaconescu, Vlad; Acuña-Parés, Ferran; Browne, Wesley R; Company, Anna

    2016-01-01

    Terminal high-valent metal-oxygen species are key reaction intermediates in the catalytic cycle of both enzymes (e.g., oxygenases) and synthetic oxidation catalysts. While tremendous efforts have been directed towards the characterization of the biologically relevant terminal manganese-oxygen and

  1. Rapid hydrogen and oxygen atom transfer by a high-valent nickel-oxygen species

    NARCIS (Netherlands)

    Corona, Teresa; Draksharapu, Apparao; Padamati, Sandeep K; Gamba, Ilaria; Martin-Diaconescu, Vlad; Acuña-Parés, Ferran; Browne, Wesley R; Company, Anna

    2016-01-01

    Terminal high-valent metal-oxygen species are key reaction intermediates in the catalytic cycle of both enzymes (e.g., oxygenases) and synthetic oxidation catalysts. While tremendous efforts have been directed towards the characterization of the biologically relevant terminal manganese-oxygen and ir

  2. Placental transfer of (125)Iodinated humanized immunoglobulin G2Δa in the Sprague Dawley rat.

    Science.gov (United States)

    Coder, P S; Thomas, J A; Stedman, D B; Bowman, C J

    2013-07-01

    Antibody-like biopharmaceuticals cross the placenta by utilizing transport pathways available for transfer of maternal antibodies to the conceptus. To characterize the timing and magnitude of this transfer in the rat, embryo/fetal biodistribution of maternally administered radiolabeled humanized IgG2 was quantified over the course of gestation using gamma counting and whole body autoradiography. The result was humanized IgG2 found in rat embryo/fetal tissues as early as gestation day 11 with a >1000-fold increase in the amount of total IgG2 by day 21. The concentration of IgG2 in rat embryo/fetal tissues generally remained unchanged from gestation day 11 to 17 with a slight increase from day 17 to 21. In addition, fetal-maternal tissue concentration ratios remained stable during organogenesis with a slight increase from gestation day 17 to 21. Based on the empirical amount of antibody present in the embryo/fetus during specific developmental windows, direct antibody binding to biological targets could potentially result in adverse developmental outcomes.

  3. About the Role of the Bottleneck/Cork Interface on Oxygen Transfer.

    Science.gov (United States)

    Lagorce-Tachon, Aurélie; Karbowiak, Thomas; Paulin, Christian; Simon, Jean-Marc; Gougeon, Régis D; Bellat, Jean-Pierre

    2016-09-01

    The transfer of oxygen through a corked bottleneck was investigated using a manometric technique. First, the effect of cork compression on oxygen transfer was evaluated without considering the glass/cork interface. No significant effect of cork compression (at 23% strain, corresponding to the compression level of cork in a bottleneck for still wines) was noticeable on the effective diffusion coefficient of oxygen. The mean value of the effective diffusion coefficient is equal to 10(-8) m(2) s(-1), with a statistical distribution ranging from 10(-10) to 10(-7) m(2) s(-1), which is of the same order of magnitude as for the non-compressed cork. Then, oxygen transfer through cork compressed in a glass bottleneck was determined to assess the effect of the glass/cork interface. In the particular case of a gradient-imposed diffusion of oxygen through our model corked bottleneck system (dry cork without surface treatment; 200 and ∼0 hPa of oxygen on both sides of the sample), the mean effective diffusion coefficient is of 5 × 10(-7) m(2) s(-1), thus revealing the possible importance of the role of the glass/stopper interface in the oxygen transfer.

  4. Distribution and mass transfer of dissolved oxygen in a multi-habitat membrane bioreactor.

    Science.gov (United States)

    Tang, Bing; Qiu, Bing; Huang, Shaosong; Yang, Kanghua; Bin, Liying; Fu, Fenglian; Yang, Huiwen

    2015-04-01

    This work investigated the DO distribution and the factors influencing the mass transfer of DO in a multi-habitat membrane bioreactor. Through the continuous measurements of an on-line automatic system, the timely DO values at different zones in the bioreactor were obtained, which gave a detailed description to the distribution of oxygen within the bioreactor. The results indicated that the growth of biomass had an important influence on the distribution of oxygen. As the extension of operational time, the volumetric oxygen mass transfer coefficient (kLa) was generally decreased. With the difference in DO values, a complex environment combining anoxic and oxic state was produced within a single bioreactor, which provided a fundamental guarantee for the total removal of TN. Aeration rate, the concentration and apparent viscosity of MLSS have different influences on kLa, but adjusting the viscosity is a feasible method to improve the mass transfer of oxygen in the bioreactor.

  5. Oxygen transfer rate during the production of alginate by Azotobacter vinelandii under oxygen-limited and non oxygen-limited conditions

    Directory of Open Access Journals (Sweden)

    Peña Carlos F

    2011-02-01

    Full Text Available Abstract Background The oxygen transfer rate (OTR and dissolved oxygen tension (DOT play an important role in determining alginate production and its composition; however, no systematic study has been reported about the independent influence of the OTR and DOT. In this paper, we report a study about alginate production and the evolution of the molecular mass of the polymer produced by a wild-type A. vinelandii strain ATCC 9046, in terms of the maximum oxygen transfer rate (OTRmax in cultures where the dissolved oxygen tension (DOT was kept constant. Results The results revealed that in the two dissolved oxygen conditions evaluated, strictly controlled by gas blending at 0.5 and 5% DOT, an increase in the agitation rate (from 300 to 700 rpm caused a significant increase in the OTRmax (from 17 to 100 mmol L-1 h-1 for DOT of 5% and from 6 to 70 mmol L-1 h-1 for DOT of 0.5%. This increase in the OTRmax improved alginate production, as well as the specific alginate production rate (SAPR, reaching a maximal alginate concentration of 3.1 g L-1 and a SAPR of 0.031 g alg g biom-1 h-1 in the cultures at OTRmax of 100 mmol L-1 h-1. In contrast, the mean molecular mass (MMM of the alginate isolated from cultures developed under non-oxygen limited conditions increased by decreasing the OTRmax, reaching a maximal of 550 kDa at an OTRmax of 17 mmol L-1 h-1 . However, in the cultures developed under oxygen limitation (0.5% DOT, the MMM of the polymer was practically the same (around 200 kDa at 300 and 700 rpm, and this remained constant throughout the cultivation. Conclusions Overall, our results showed that under oxygen-limited and non oxygen-limited conditions, alginate production and its molecular mass are linked to the OTRmax, independently of the DOT of the culture.

  6. Characterization of placental cholesterol transport

    DEFF Research Database (Denmark)

    Lindegaard, Marie L; Wassif, Christopher A; Vaisman, Boris

    2008-01-01

    Patients with Smith-Lemli-Opitz syndrome (SLOS) are born with multiple congenital abnormalities. Postnatal cholesterol supplementation is provided; however, it cannot correct developmental malformations due to in utero cholesterol deficit. Increased transport of cholesterol from maternal to fetal...... circulation might attenuate congenital malformations. The cholesterol transporters Abca1, Abcg1, and Sr-b1 are present in placenta; however, their potential role in placental transport remains undetermined. In mice, expression analyses showed that Abca1 and Abcg1 transcripts increased 2-3-fold between...... embryonic days 13.5 and 18.5 in placental tissue; whereas, Sr-b1 expression decreased. To examine the functional role of Abca1, Abcg1 and Sr-b1 we measured the maternal-fetal transfer of (14)C-cholesterol in corresponding mutant embryos. Disruption of either Abca1 or Sr-b1 decreased cholesterol transfer...

  7. Investigation of the contact charge transfer absorption of organic solvents with oxygen for use in oxygen determination.

    Science.gov (United States)

    Choi, M F; Hawkins, P

    1995-07-01

    The contact charge transfer (CCT) absorption spectra of dimethylsulphoxide (DMSO), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), ethanol, methanol, water, benzene (Bz), N,N'-diethylaniline (DEA), N,N'-dimethyl-p-toluidine (DMT) and N,N'-diethyl-p-toluidine with molecular oxygen have been investigated. These solvents form strong ultraviolet/visible CCT absorption spectra with intensities that are related to the partial pressure of the applied oxygen. DMSO, DMF, DMA, Bz, DEA and DMT are shown to form 1:1 molecular contact complexes with molecular oxygen. A simple oxygen sensing system is described using CCT absorption spectroscopy of DMT at a wavelength of 400 nm, with a gas flow rate of 60 cm(3) min(-1) through the solvent in a cuvette with a pathlength of 1 cm. Inexpensive plastic fibres are used to relay the light from a xenon lamp source to the cuvette and back to a photo-detector. The response of the sensing system to changes in oxygen concentration is reversible, non-linear and in good agreement with the Beer-Lambert law. The most sensitive response region is from 0 to 20% O(2) with a change in signal level of about 35%. The solvent used shows no deterioration in performance over a long period and can be used to determine gaseous oxygen concentrations from 0 to 100%. It does not respond to carbon dioxide.

  8. Charge transfer mediator based systems for electrocatalytic oxygen reduction

    Energy Technology Data Exchange (ETDEWEB)

    Stahl, Shannon S.; Gerken, James B.; Anson, Colin W.

    2017-07-18

    Disclosed are systems for the electrocatalytic reduction of oxygen, having redox mediator/redox catalyst pairs and an electrolyte solution in contact with an electrode. The redox mediator is included in the electrolyte solution, and the redox catalyst may be included in the electrolyte solution, or alternatively, may be in contact with the electrolyte solution. In one form a cobalt redox catalyst is used with a quinone redox mediator. In another form a nitrogen oxide redox catalyst is used with a nitroxyl type redox mediator. The systems can be used in electrochemical cells wherein neither the anode nor the cathode comprise an expensive metal such as platinum.

  9. Revisiting mobilisation of skeletal lead during pregnancy based on monthly sampling and cord/maternal blood lead relationships confirm placental transfer of lead.

    Science.gov (United States)

    Gulson, Brian; Mizon, Karen; Korsch, Michael; Taylor, Alan

    2016-04-01

    those in the maternal blood samples taken prior to parturition with an R (2) 0.94 for the migrant subjects and R (2) 0.74 for Australian subjects for (206)Pb/(204)Pb ratios, supporting the concept of placental transfer of mobilised skeletal stores of Pb.

  10. Placental vascular responses are dependent on surrounding tissue

    DEFF Research Database (Denmark)

    Brøgger, Torbjørn Halle

    Background: The placenta is the base for the exchange of nutrients, oxygen and waste products for the fetus. The placental vessels hold a crucial role in regulation the blood flow, and a compromised placental function leads to serious complications such as fetal death or growth retardation. An in...

  11. Placental vascular responses are dependent on surrounding tissue

    DEFF Research Database (Denmark)

    Brøgger, Torbjørn Halle

    Background. The placenta is the base for the exchange of nutrients, oxygen and waste products for the fetus.The placental vessels hold a crucial role in regulation the blood flow, and a compromised placental function leads to serious complications such as fetal death or growth retardation...

  12. Improvement of AD Biosynthesis Response to Enhanced Oxygen Transfer by Oxygen Vectors in Mycobacterium neoaurum TCCC 11979.

    Science.gov (United States)

    Su, Liqiu; Shen, Yanbing; Gao, Tian; Luo, Jianmei; Wang, Min

    2017-08-01

    In steroid biotransformation, soybean oil can improve the productivity of steroids by increasing substrate solubility and strengthen the cell membrane permeability. However, little is known of its role as oxygen carrier and its mechanism of promoting the steroid biotransformation. In this work, soybean oil used as oxygen vector for the enhancement of androst-4-ene-3,17-dione (AD) production by Mycobacterium neoaurum TCCC 11979 (MNR) was investigated. Upon the addition of 16% (v/v) soybean oil, the volumetric oxygen transfer coefficient (K L a) value increased by 44%, and the peak molar yield of AD (55.76%) was achieved. Analysis of intracellular cofactor levels showed high NAD(+), ATP level, and a low NADH/NAD(+) ratio. Meanwhile, the two key enzymes of the tricarboxylic acid (TCA) cycle, namely, isocitrate dehydrogenase and α-ketoglutarate dehydrogenase, were upregulated after incubation with soybean oil. These enhancements induced by the increasing of oxygen supply showed positive effects on phytosterol (PS) bioconversion. Results could contribute to the understanding of effects of soybean oil as oxygen vector on steroid biotransformation and provided a convenient method for enhancing the efficiency of aerobic steroid biocatalysis.

  13. Studies on the rheology and oxygen mass transfer in the clavulanic acid production by Streptomyces clavuligerus

    Directory of Open Access Journals (Sweden)

    E. R. Gouveia

    2000-12-01

    Full Text Available In the present work rheological characteristics and volumetric oxygen transfer coefficient (kLa were investigated during batch cultivations of Streptomyces clavuligerus NRRL 3585 for production of clavulanic acid. The experimental rheological data could be adequately described in terms of the power law model and logistic equation. Significant changes in the rheological parameters consistency index (K and flow behavior index (n were observed with the fermentation evolution. Interesting correlations between the consistency index (K/biomass concentration (C X and the flow behavior index (n/biomass concentration were proposed. Volumetric oxygen mass transfer coefficient (kLa was determined by the gas balance method. Classical correlation relating the volumetric oxygen mass transfer coefficient to the operating conditions, physical and to transport properties, including apparent viscosity (muap, could be applied to the experimental results.

  14. Promotion of multi-electron transfer for enhanced photocatalysis: A review focused on oxygen reduction reaction

    Science.gov (United States)

    Wang, Changhua; Zhang, Xintong; Liu, Yichun

    2015-12-01

    Semiconductor photocatalysis has attracted significant interest for solar light induced environmental remediation and solar fuel generation. As is well known, photocatalytic performance is determined by three steps: photoexcitation, separation and transport of photogenerated charge carriers, and surface reactions. To achieve higher efficiency, significant efforts have been made on improvement of efficiency of above first two steps, which have been well documented in recent review articles. In contrast, this review intends to focus on strategies moving onto the third step of improvement for enhanced photocatalysis wherein active oxygen species including superoxide radical, hydrogen peroxide, hydroxyl radical are in situ detected. Particularly, surface electron-transfer reduction of oxygen over single component photocatalysts is reviewed and systems enabling multi-electron transfer induced oxygen reduction reaction (ORR) are highlighted. It is expected this review could provide a guideline for readers to better understand the critical role of ORR over photocatalyst in charge carrier separation and transfer and obtain reliable results for enhanced aerobic photocatalysis.

  15. Construction of cyclic enones via gold-catalyzed oxygen transfer reactions

    Directory of Open Access Journals (Sweden)

    Gerald B. Hammond

    2011-05-01

    Full Text Available During the last decade, gold-catalyzed reactions have become a tour de force in organic synthesis. Recently, the gold-, Brønsted acid- or Lewis acid-catalyzed oxygen transfer from carbonyl to carbon–carbon triple bond, the so-called alkyne–carbonyl metathesis, has attracted much attention because this atom economical transformation generates α,β-unsaturated carbonyl derivatives which are of great interest in synthetic organic chemistry. This mini-review focuses on the most recent achievements on gold-catalyzed oxygen transfer reactions of tethered alkynones, diynes or alkynyl epoxides to cyclic enones. The corresponding mechanisms for the transformations are also discussed.

  16. Oxygen supply in disposable shake-flasks: prediction of oxygen transfer rate, oxygen saturation and maximum cell concentration during aerobic growth.

    Science.gov (United States)

    Schiefelbein, Sarah; Fröhlich, Alexander; John, Gernot T; Beutler, Falco; Wittmann, Christoph; Becker, Judith

    2013-08-01

    Dissolved oxygen plays an essential role in aerobic cultivation especially due to its low solubility. Under unfavorable conditions of mixing and vessel geometry it can become limiting. This, however, is difficult to predict and thus the right choice for an optimal experimental set-up is challenging. To overcome this, we developed a method which allows a robust prediction of the dissolved oxygen concentration during aerobic growth. This integrates newly established mathematical correlations for the determination of the volumetric gas-liquid mass transfer coefficient (kLa) in disposable shake-flasks from the filling volume, the vessel size and the agitation speed. Tested for the industrial production organism Corynebacterium glutamicum, this enabled a reliable design of culture conditions and allowed to predict the maximum possible cell concentration without oxygen limitation.

  17. Placental transfusion: a review

    Science.gov (United States)

    Katheria, A C; Lakshminrusimha, S; Rabe, H; McAdams, R; Mercer, J S

    2017-01-01

    Recently there have been a number of studies and presentations on the importance of providing a placental transfusion to the newborn. Early cord clamping is an avoidable, unphysiologic intervention that prevents the natural process of placental transfusion. However, placental transfusion, although simple in concept, is affected by multiple factors, is not always straightforward to implement, and can be performed using different methods, making this basic procedure important to discuss. Here, we review three placental transfusion techniques: delayed cord clamping, intact umbilical cord milking and cut-umbilical cord milking, and the evidence in term and preterm newborns supporting this practice. We will also review several factors that influence placental transfusion, and discuss perceived risks versus benefits of this procedure. Finally, we will provide key straightforward concepts and implementation strategies to ensure that placental-to-newborn transfusion can become routine practice at any institution. PMID:27654493

  18. Adenovirus-mediated gene transfer of placental growth factor to perivascular tissue induces angiogenesis via upregulation of the expression of endogenous vascular endothelial growth factor-A

    NARCIS (Netherlands)

    Roy, H; Bhardwaj, S; Babu, M; Jauhiainen, S; Herzig, KH; Bellu, AR; Haisma, HJ; Carmeliet, P; Alitalo, K; Yla-Herttuala, S

    2005-01-01

    Placental growth factor (PIGF) is a member of the vascular endothelial growth factor (VEGF) family that binds specifically to VEGF receptor (VEGFR)-1. However, the mechanism of PIGF- and VEGFR-1-mediated angiogenesis has remained unclear and some in vitro studies suggest that VEGF-A/VEGFR-2

  19. Oxygen transfer dynamics and activated sludge floc structure under different sludge retention times at low dissolved oxygen concentrations.

    Science.gov (United States)

    Fan, Haitao; Liu, Xiuhong; Wang, Hao; Han, Yunping; Qi, Lu; Wang, Hongchen

    2017-02-01

    In activated sludge systems, the aeration process consumes the most energy. The energy cost can be dramatically reduced by decreasing the operating dissolved oxygen (DO) concentration. However, low DO may lead to incomplete nitrification and poor settling performance of activated sludge flocs (ASFs). This study investigates oxygen transfer dynamics and settling performances of activated sludge under different sludge retention times (SRTs) and DO conditions using microelectrodes and microscopic techniques. Our experimental results showed that with longer SRTs, treatment capacity and settling performances of activated sludge improved due to smaller floc size and less extracellular polymeric substances (EPS). Long-term low DO conditions produced larger flocs and more EPS per unit sludge, which produced a more extensive anoxic area and led to low oxygen diffusion performance in flocs. Long SRTs mitigated the adverse effects of low DO. According to the microelectrode analysis and fractal dimension determination, smaller floc size and less EPS in the long SRT system led to high oxygen diffusion property and more compact floc structure that caused a drop in the sludge volume index (SVI). In summary, our results suggested that long SRTs of activated sludge can improve the operating performance under low DO conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Rapid Hydrogen and Oxygen Atom Transfer by a High-Valent Nickel-Oxygen Species.

    Science.gov (United States)

    Corona, Teresa; Draksharapu, Apparao; Padamati, Sandeep K; Gamba, Ilaria; Martin-Diaconescu, Vlad; Acuña-Parés, Ferran; Browne, Wesley R; Company, Anna

    2016-10-05

    Terminal high-valent metal-oxygen species are key reaction intermediates in the catalytic cycle of both enzymes (e.g., oxygenases) and synthetic oxidation catalysts. While tremendous efforts have been directed toward the characterization of the biologically relevant terminal manganese-oxygen and iron-oxygen species, the corresponding analogues based on late-transition metals such as cobalt, nickel or copper are relatively scarce. This scarcity is in part related to the "Oxo Wall" concept, which predicts that late transition metals cannot support a terminal oxido ligand in a tetragonal environment. Here, the nickel(II) complex (1) of the tetradentate macrocyclic ligand bearing a 2,6-pyridinedicarboxamidate unit is shown to be an effective catalyst in the chlorination and oxidation of C-H bonds with sodium hypochlorite as terminal oxidant in the presence of acetic acid (AcOH). Insight into the active species responsible for the observed reactivity was gained through the study of the reaction of 1 with ClO(-) at low temperature by UV-vis absorption, resonance Raman, EPR, ESI-MS, and XAS analyses. DFT calculations aided the assignment of the trapped chromophoric species (3) as a nickel-hypochlorite species. Despite the fact that the formal oxidation state of the nickel in 3 is +4, experimental and computational analysis indicate that 3 is best formulated as a Ni(III) complex with one unpaired electron delocalized in the ligands surrounding the metal center. Most remarkably, 3 reacts rapidly with a range of substrates including those with strong aliphatic C-H bonds, indicating the direct involvement of 3 in the oxidation/chlorination reactions observed in the 1/ClO(-)/AcOH catalytic system.

  1. Development of a model to determine mass transfer coefficient and oxygen solubility in bioreactors

    Directory of Open Access Journals (Sweden)

    Johnny Lee

    2017-02-01

    where T is in degree Kelvin, and the subscripts refer to degree Celsius; E, ρ, σ are properties of water. Furthermore, using data from published data on oxygen solubility in water, it was found that solubility bears a linear and inverse relationship with the mass transfer coefficient.

  2. An Experiment to Introduce Mass Transfer Concepts Using a Commercial Hollow Fiber Blood Oxygenator

    Science.gov (United States)

    McIver, Keith; Merrill, Thomas; Farrell, Stephanie

    2017-01-01

    A commercial hollow fiber blood oxygenation laboratory experiment was used to introduce lower level engineering students to mass balances in a two-phase system. Using measured values of concentration and flow rate, students calculated the rate of mass transfer from the gas phase and into the liquid phase, and compared the two values to determine…

  3. Synthesis, characterisation, and oxygen atom transfer reactions involving the first gold(I)-alkylperoxo complexes.

    Science.gov (United States)

    Collado, Alba; Gómez-Suárez, Adrián; Oonishi, Yoshihiro; Slawin, Alexandra M Z; Nolan, Steven P

    2013-11-25

    The synthesis of a new class of organogold species containing a peroxo moiety is reported. Complexes [Au(IPr)(OO(t)Bu)] and [Au(SIPr)(OO(t)Bu)] have been synthesised via a straightforward methodology using the parent gold(I) hydroxide complexes as synthons. These complexes have been successfully used in oxygen-transfer reactions to triphenylphosphine.

  4. Modelling of the heat transfer during oxygen atoms recombination on metallic surfaces in a plasma reactor

    NARCIS (Netherlands)

    Cavadias, S; Cauquot, P; Amouroux, J

    1997-01-01

    Space shuttle overheating during the re-entry phase, due to catalytic oxygen recombination on the thermal protection system, is a problem of practical and theoretical interest. The energy transfer is characterised by the product of the accommodation and the recombination coefficients. Previous measu

  5. Effects of CeCl3 on Energy Transfer and Oxygen Evolution in Spinach Photosystem Ⅱ

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Due to 4f electron characteristics and alternation valence, cerium involved in an oxidation-reduction reaction in plant, closely relating to photosynthesis. Our studies proved that cerium could promote photosynthesis and greatly improve spinach growth. However, the mechanism of promoting energy transfer and conversion by cerium remains unclear. Here we reported that the effects of Ce3+ on energy transfer and oxygen evolution in photosystem Ⅱ(PSⅡ) isolated from spinach, which was related to 4f electron characteristics and alternation valence in Ce molecule. The methods of absorption spectrum, fluorescence spectrum were used in the research. Results showed that Ce3+ treatment at low concentration could suitably change PSⅡ microenvironment, increase the absorbance of visible light, improve the energy transfer among amino acids within PSⅡ protein-pigment complex, and accelerate energy transport from tyrosine residue to chlorophyll a. In summary, the photochemical activity of PSⅡ(fluorescence quantum yield) and its oxygen evolving rate were enhanced by Ce3+.

  6. Providing a Placental Transfusion in Newborns Who Need Resuscitation

    Science.gov (United States)

    Katheria, Anup C.; Brown, Melissa K.; Rich, Wade; Arnell, Kathy

    2017-01-01

    Over the past decade, there have been several studies and reviews on the importance of providing a placental transfusion to the newborn. Allowing a placental transfusion to occur by delaying the clamping of the umbilical cord is an extremely effective method of enhancing arterial oxygen content, increasing cardiac output, and improving oxygen delivery. However, premature and term newborns who require resuscitation have impaired transitional hemodynamics and may warrant different methods to actively provide a placental transfusion while still allowing for resuscitation. In this review, we will provide evidence for providing a placental transfusion in these circumstances and methods for implementation. Several factors including cord clamping time, uterine contractions, umbilical blood flow, respirations, and gravity play an important role in determining placental transfusion volumes. Finally, while many practitioners agree that a placental transfusion is beneficial, it is not always straightforward to implement and can be performed using different methods, making this basic procedure important to discuss. We will review three placental transfusion techniques: delayed cord clamping, intact umbilical cord milking, and cut-umbilical cord milking. We will also review resuscitation with an intact cord and the evidence in term and preterm newborns supporting this practice. We will discuss perceived risks versus benefits of these procedures. Finally, we will provide key straightforward concepts and implementation strategies to ensure that placental-to-newborn transfusion can become routine practice at any institution. PMID:28180126

  7. Oxygen atom transfer to a half-sandwich iridium complex: clean oxidation yielding a molecular product.

    Science.gov (United States)

    Turlington, Christopher R; White, Peter S; Brookhart, Maurice; Templeton, Joseph L

    2014-03-12

    The oxidation of [Ir(Cp*)(phpy)(NCAr(F))][B(Ar(F))4] (1; Cp* = η(5)-pentamethylcyclopentadienyl, phpy = 2-phenylene-κC(1')-pyridine-κN, NCAr(F) = 3,5-bis(trifluoromethyl)benzonitrile, B(Ar(F))4 = tetrakis[3,5-bis(trifluoromethyl)phenyl]borate) with the oxygen atom transfer (OAT) reagent 2-tert-butylsulfonyliodosobenzene (sPhIO) yielded a single, molecular product at -40 °C. New Ir(Cp*) complexes with bidentate ligands derived by oxidation of phpy were synthesized to model possible products resulting from oxygen atom insertion into the iridium-carbon and/or iridium-nitrogen bonds of phpy. These new ligands were either cleaved from iridium by water or formed unreactive, phenoxide-bridged iridium dimers. The reactivity of these molecules suggested possible decomposition pathways of Ir(Cp*)-based water oxidation catalysts with bidentate ligands that are susceptible to oxidation. Monitoring the [Ir(Cp*)(phpy)(NCAr(F))](+) oxidation reaction by low-temperature NMR techniques revealed that the reaction involved two separate OAT events. An intermediate was detected, synthesized independently with trapping ligands, and characterized. The first oxidation step involves direct attack of the sPhIO oxidant on the carbon of the coordinated nitrile ligand. Oxygen atom transfer to carbon, followed by insertion into the iridium-carbon bond of phpy, formed a coordinated organic amide. A second oxygen atom transfer generated an unidentified iridium species (the "oxidized complex"). In the presence of triphenylphosphine, the "oxidized complex" proved capable of transferring one oxygen atom to phosphine, generating phosphine oxide and forming an Ir-PPh3 adduct in 92% yield. The final Ir-PPh3 product was fully characterized.

  8. Oxygen mass transfer and scale-up studies in baffled roller bioreactors.

    Science.gov (United States)

    Nikakhtari, H; Song, W; Nemati, M; Hill, G A

    2014-02-01

    Oxygen mass transfer was studied in conventional, bead mill and baffled roller bioreactors. Using central composite rotational design, impacts of size, rotation speed and working volume on the oxygen mass transfer were evaluated. Baffled roller bioreactor outperformed its conventional and bead mill counterparts, with the highest k(L)a obtained in these configurations being 0.58, 0.19, 0.41 min(-1), respectively. Performances of the bead mill and baffled roller bioreactor were only comparable when a high bead loading (40%) was applied. Regardless of configuration increase in rotation speed and decrease in working volume improved the oxygen mass transfer rate. Increase in size led to enhanced mass transfer and higher k(L)a in baffled roller bioreactor (0.49 min(-1) for 2.2 L and 1.31 min(-1) for 55 L bioreactors). Finally, the experimentally determined k(L)a in the baffled roller bioreactors of different sizes fit reasonably well to an empirical correlation describing the k(L)a in terms of dimensionless numbers.

  9. Evaluation of oxygen transfer parameters of fine-bubble aeration system in plug flow aeration tank of wastewater treatment plant

    Institute of Scientific and Technical Information of China (English)

    Xiaohong Zhou; Yuanyuan Wu; Hanchang Shi; Yanqing Song

    2013-01-01

    Knowledge of the oxygen mass transfer of aerators under operational conditions in a full-scale wastewater treatment plant (WWTP) is meaningful for the optimization of WWTP,however,scarce to best of our knowledge.Through analyzing a plug flow aeration tank in the Lucun WWTP,in Wuxi,China,the oxygenation capacity of fine-bubble aerators under process conditions have been measured insitu using the off-gas method and the non-steady-state method.The off-gas method demonstrated that the aerators in different corridors in the aeration tank of WWTP had significantly different oxygen transfer performance; furthermore,the aerators in the same corridor shared almost equal oxygen transfer performance over the course of a day.Results measured by the two methods showed that the oxygen transfer performance of fine-bubble aerators in the aeration tank decreased dramatically compared with that in the clean water.The loss of oxygen transfer coefficient was over 50% under low-aeration conditions (aeration amount < 0.67 Nm3/hr).However,as the aeration amount reached 0.96 Nm3/hr,the discrepancy of oxygen transfer between the process condition and clean water was negligible.The analysis also indicated that the non-steady-state and off-gas methods resulted in comparable estimates of oxygen transfer parameters for the aerators under process conditions.

  10. Triplet-triplet energy transfer and protection mechanisms against singlet oxygen in photosynthesis

    Science.gov (United States)

    Kihara, Shigeharu

    individual BChl pigments within that photosynthetic antenna complex are accessed via their triplet state dynamics. It is found that the currently used exciton model of FMO needs to be revised. It is also shown that triplet excited states can be readily transferred between the molecules. It is proposed that the triplet energy transfer between the BChl molecules can also serve as a protection mechanism. Finally, it is inferred that at least one of the BChl molecules within the FMO has a triplet state energy that is lower than that of singlet oxygen. This effectively prevents the formation of singlet oxygen and protects the complex from oxidative damage. The energy of BChl is apparently lowered by the specific protein environment, as in solution its energy is measured to be somewhat higher than the energy of singlet oxygen. Finally, the results of the triplet energy transfer within the cytochrome b6f complex are presented. This part of the work is not conclusive, and some of the problems encountered in experiments are described, as well as a new method of sample degassing developed for this type of study is presented.

  11. Studies on oxygen mass transfer in stirred bioreactors 2: Suspensions of bacteria, yeasts and fungis

    Directory of Open Access Journals (Sweden)

    Galaction Anca-Irina

    2003-01-01

    Full Text Available The aim of these experiments is to study the oxygen mass transfer rate by means of the mass transfer coefficient, for a stirred bioreactor and different fermentation broths, using a large domain of operating variables. For quantifying the effects of the considered factors (concentration and morphology of the biomass, specific power input, superficial air velocity surface aeration on ka, the experiments were carried out for non-respirating biomass suspensions of Propionibacterium shermanii Saccharomyces cerevisiae and Penicillium chrysogenum, mycelial aggregates (pellets and free mycelia morphological structures.

  12. Using eddy covariance to estimate air-sea gas transfer velocity for oxygen

    Science.gov (United States)

    Andersson, Andreas; Rutgersson, Anna; Sahlée, Erik

    2016-07-01

    Air-sea gas transfer velocity for O2 is calculated using directly measured fluxes with the eddy covariance technique. It is a direct method and is frequently used to determine fluxes of heat, humidity, and CO2, but has not previously been used to estimate transfer velocities for O2, using atmospheric eddy covariance data. The measured O2 fluxes are upward directed, in agreement with the measured air-sea gradient of the O2 concentration, and opposite to the direction of the simultaneously measured CO2 fluxes. The transfer velocities estimated from measurements are compared with prominent wind speed parameterizations of the transfer velocity for CO2 and O2, previously established from various measurement techniques. Our result indicates stronger wind speed dependence for the transfer velocity of O2 compared to CO2 starting at intermediate wind speeds. This stronger wind speed dependence appears to coincide with the onset of whitecap formation in the flux footprint and the strong curvature of a cubic wind-dependent function for the transfer velocity provides the best fit to the data. Additional data using the measured O2 flux and an indirect method (based on the Photosynthetic Quotient) to estimate oxygen concentration in water, support the stronger wind dependence for the transfer velocity of O2 compared to CO2.

  13. Evaluation of oxygen transfer parameters of fine-bubble aeration system in plug flow aeration tank of wastewater treatment plant.

    Science.gov (United States)

    Zhou, Xiaohong; Wu, Yuanyuan; Shi, Hanchang; Song, Yanqing

    2013-02-01

    Knowledge of the oxygen mass transfer of aerators under operational conditions in a full-scale wastewater treatment plant (WWTP) is meaningful for the optimization of WWTP, however, scarce to best of our knowledge. Through analyzing a plug flow aeration tank in the Lucun WWTP, in Wuxi, China, the oxygenation capacity of fine-bubble aerators under process conditions have been measured in-situ using the off-gas method and the non-steady-state method. The off-gas method demonstrated that the aerators in different corridors in the aeration tank of WWTP ha d significantly different oxygen transferperformance; furthermore, the aerators in the samecorridor shared almost equal oxygen transfer performance over the course of a day. Results measured by the two methods showed that the oxygen transfer performance of fine-bubble aerators in the aeration tank decreased dramatically compared with that in the clean water. The loss of oxygen transfer coefficient was over 50% under low-aeration conditions (aeration amount aeration amount reached 0.96 Nm3/hr, the discrepancy of oxygen transfer between the process condition and clean water was negligible. The analysis also indicated that the non-steady-state and off-gas methods resulted in comparable estimates of oxygen transfer parameters for the aerators under process conditions.

  14. Charge transfer and weak bonding between molecular oxygen and graphene zigzag edges at low temperatures

    CERN Document Server

    Boukhvalov, D W; Shames, A I; Takai, K; Hayashi, T; Enoki, T

    2016-01-01

    Electron paramagnetic resonance (EPR) study of air-physisorbed defective carbon nano-onions evidences in favor of microwave assisted formation of weakly-bound paramagnetic complexes comprising negatively-charged O2- ions and edge carbon atoms carrying pi-electronic spins. These complexes being located on the graphene edges are stable at low temperatures but irreversibly dissociate at temperatures above 50-60 K. These EPR findings are justified by density functional theory (DFT) calculations demonstrating transfer of an electron from the zigzag edge of graphene-like material to oxygen molecule physisorbed on the graphene sheet edge. This charge transfer causes changing the spin state of the adsorbed oxygen molecule from S = 1 to S = 1/2 one. DFT calculations show significant changes of adsorption energy of oxygen molecule and robustness of the charge transfer to variations of the graphene-like substrate morphology (flat and corrugated mono- and bi-layered graphene) as well as edges passivation. The presence of...

  15. Modeling of Oxygen Transfer Correlations for Stirred Tank Bioreactor Agitated with Atypical Helical Ribbon Impeller

    Directory of Open Access Journals (Sweden)

    Mohd S. Mohamed

    2009-01-01

    Full Text Available Problem Statement: Mixing filamentous fungi entails delicate balance between promoting high volumetric oxygen transfer coefficient (kLa while keeping low hydrodynamic stresses in the microenvironment of cultures. This study examined the oxygen transfer capability of a prototype low shear helical impeller as a potential replacement for the standard Rushton turbine. Approach: The dependence of kLa upon specific power uptake, superficial gas velocity and apparent viscosity were examined under coalescent, non-coalescent and viscous pseudoplastic fluids scenario using dynamic gassing out technique. Subsequently, collected data were treated under historical data design of response surface methodology. Results: Three empirical power law kLa correlations were developed for each fluid. Correlation comparison with literature models for single turbine agitation suggest higher kLa augmentation within 1.5-3.6 folds for helical impeller in distilled water and as high as 78% improvement in electrolytes fluid. However impeller performance is comparatively 10% lower against theoretical kLa of triple turbines arrangement for power uptake between 0-1600 W m-3. In case of carboxymethylcellulose, better oxygen transfer is expected for design with higher proportionality of impeller-to-tank internal diameter. Conclusions: Helical impeller performance as gas-liquid contactor is comparable to single and triple Rushtons turbines, with superficial gas velocity proved to be more influential than power uptake in non-viscous liquids and vice versa in viscous pseudoplastic fluids.

  16. Oxygen mass transfer for an immobilised biofilm of Phanerochaete chrysosporium in a membrane gradostat reactor

    Directory of Open Access Journals (Sweden)

    S. K. O. Ntwampe

    2008-12-01

    Full Text Available A novel system, the membrane gradostat reactor (MGR, designed for the continuous production of secondary metabolites, has been shown to have higher production per reactor volume than batch culture systems. The MGR system mimics the natural environment in which wild occurring microorganism biofilms flourish. The biofilms are immobilised on the external surface of an ultrafiltration membrane where substrate distribution gradients are established across the biofilm. The hypothesis that, dissolved oxygen (DO mass transfer parameters obtained in submerged pellets can be used to describe and model DO mass transfer parameters in the MGR, was refuted. Phanerochaete chrysosporium biofilms, immobilised on ultrafiltration capillary membranes in the MGR systems were used to quantify DO distribution using a Clark-type microsensor. The DO penetration depth decreased with increasing biofilm thickness, which resulted in the formation of anaerobic zones in the biofilms. Oxygen flux values of 0.27 to 0.7 g/(m².h were obtained during the MGR operation. The consumption of oxygen and the Monod saturation constants used in the modelling of oxygen distribution in immobilised biofilms were in the range of 894.53 to 2739.70 g/(m³.h and 0.041 to 0.999 g/m³, respectively.

  17. The effect of bubbles on air-water oxygen transfer in the breaker zone

    Science.gov (United States)

    Kakuno, Shohachi; Moog, Douglas B.; Tatekawa, Tetsuya; Takemura, Kenji; Yamagishi, Tatsuya

    The effect of bubbles entrained in the breaker zone on air-water oxygen transfer is examined. First, the area of bubbles entrained by breakers generated on a sloping bottom in a wave tank is analyzed using a color image sensor which can count the pixel number of a specific color in a frame. It was found that the time-averaged pixel number over a wave period has a strong relationship to the energy dissipation rate per unit mass of the breaker. The time-averaged pixel number is then incorporated with some modification into an equation proposed by Eckenfelder for the calculation of the mass transfer coefficient from bubble surfaces in an aeration tank. The coefficient resulting from the modified equation shows a strong relationship between the mass transfer coefficient and the dissipation rate.

  18. Placental gene therapy

    OpenAIRE

    David, A. L.; Ashcroft, R

    2009-01-01

    Gene therapy uses genetic material as a drug delivery vehicle to express therapeutic proteins. Placental gene therapy may be useful for correction of two important obstetric conditions, foetal growth restriction and pre-eclampsia in which there is a failure of the physiological trophoblast remodelling of the uterine spiral arteries in early pregnancy. The patient in this scenario is the foetus. Placental gene therapy might be justifiable when: there is reasonable certainty that the foetus wil...

  19. Heterogeneous electron transfer and oxygen reduction reaction at nanostructured iron(II) phthalocyanine and its MWCNTs nanocomposites

    CSIR Research Space (South Africa)

    Mamuru, SA

    2010-05-01

    Full Text Available Electron transfer and oxygen reduction dynamics at nanostructured iron(II) phthalocyanine/multi-walled carbon nanotubes composite supported on an edge plane pyrolytic graphite electrode (EPPGE-MWCNT-nanoFePc) platform have been reported. All...

  20. Accelerated Oxygen Atom Transfer and C-H Bond Oxygenation by Remote Redox Changes in Fe3 Mn-Iodosobenzene Adducts.

    Science.gov (United States)

    de Ruiter, Graham; Carsch, Kurtis M; Gul, Sheraz; Chatterjee, Ruchira; Thompson, Niklas B; Takase, Michael K; Yano, Junko; Agapie, Theodor

    2017-03-24

    We report the synthesis, characterization, and reactivity of [LFe3 (PhPz)3 OMn((s) PhIO)][OTf]x (3: x=2; 4: x=3), where 4 is one of very few examples of iodosobenzene-metal adducts characterized by X-ray crystallography. Access to these rare heterometallic clusters enabled differentiation of the metal centers involved in oxygen atom transfer (Mn) or redox modulation (Fe). Specifically, (57) Fe Mössbauer and X-ray absorption spectroscopy provided unique insights into how changes in oxidation state (Fe(III)2 Fe(II) Mn(II) vs. Fe(III)3 Mn(II) ) influence oxygen atom transfer in tetranuclear Fe3 Mn clusters. In particular, a one-electron redox change at a distal metal site leads to a change in oxygen atom transfer reactivity by ca. two orders of magnitude.

  1. Rheology, oxygen transfer, and molecular weight characteristics of poly(glutamic acid) fermentation by Bacillus subtilis.

    Science.gov (United States)

    Richard, Andrew; Margaritis, Argyrios

    2003-05-01

    Poly(glutamic acid) (PGA) is a water-soluble, biodegradable biopolymer that is produced by microbial fermentation. Recent research has shown that PGA can be used in drug delivery applications for the controlled release of paclitaxel (Taxol) in cancer treatment. A fundamental understanding of the key fermentation parameters is necessary to optimize the production and molecular weight characteristics of poly(glutamic acid) by Bacillus subtilis for paclitaxel and other applications of pharmaceuticals for controlled release. Because of its high molecular weight, PGA fermentation broths exhibit non-Newtonian rheology. In this article we present experimental results on the batch fermentation kinetics of PGA production, mass transfer of oxygen, specific oxygen uptake rate, broth rheology, and molecular weight characterization of the PGA biopolymer.

  2. A validated CFD model to predict O₂ and CO₂ transfer within hollow fiber membrane oxygenators.

    Science.gov (United States)

    Hormes, Marcus; Borchardt, Ralf; Mager, Ilona; Rode, Thomas Schmitz; Behr, Marek; Steinseifer, Ulrich

    2011-03-01

    Hollow fiber oxygenators provide gas exchange to and from the blood during heart surgery or lung recovery. Minimal fiber surface area and optimal gas exchange rate may be achieved by optimization of hollow fiber shape and orientation (1). In this study, a modified CFD model is developed and validated with a specially developed micro membrane oxygenator (MicroMox). The MicroMox was designed in such a way that fiber arrangement and bundle geometry are highly reproducible and potential flow channeling is avoided, which is important for the validation. Its small size (V(Fluid)=0.04 mL) allows the simulation of the entire bundle of 120 fibers. A non-Newtonian blood model was used as simulation fluid. Physical solubility and chemical bond of O₂ and CO₂ in blood was represented by the numerical model. Constant oxygen partial pressure at the pores of the fibers and a steady state flow field was used to calculate the mass transport. In order to resolve the entire MicroMox fiber bundle, the mass transport was simulated for symmetric geometry sections in flow direction. In vitro validation was achieved by measurements of the gas transfer rates of the MicroMox. All measurements were performed according to DIN EN 12022 (2) using porcine blood. The numerical simulation of the mass transfer showed good agreement with the experimental data for different mass flows and constant inlet partial pressures. Good agreement could be achieved for two different fiber configurations. Thus, it was possible to establish a validated model for the prediction of gas exchange in hollow fiber oxygenators.

  3. Influence of medium composition on oxygen transfer rate in animal cell culture

    OpenAIRE

    Toye, Dominique; Galifi, Alain; Salmon, Thierry; Verdin, Emeline; Crine, Michel

    2009-01-01

    Experiments were conducted in a 0.25 m diameter bubble column to investigate the effect of animal cell culture medium composition on oxygen transfer rate. Air is used as the dispersed phase. The gas superficial velocity is varied between 0.4 and 2 cm/s (aeration rate ranging between 0.05 and 0.25 vvm) and the bubble column is thus operated in the homogenous regime. Aqueous solutions the composition (electrolyte, protein concentrations) of which mimics a mammalian cell culture medium) are us...

  4. The placental exposome: Placental determinants of fetal adiposity and postnatal body composition

    NARCIS (Netherlands)

    R.M. Lewis (R.); H. Demmelmair (Hans); R. Gaillard (Romy); N. Godfrey; S. Hauguel-De Mouzon (S.); B. Huppertz (B.); E. Larque (E.); R. Saffery (R.); M.E. Symonds (M.); G. Desoye (G.)

    2013-01-01

    textabstractOffspring of obese and diabetic mothers are at increased risk of being born with excess adiposity as a consequence of their intrauterine environment. Excessive fetal fat accretion reflects additional placental nutrient transfer, suggesting an effect of the maternal environment on

  5. Risk factors of placental abruption

    OpenAIRE

    2013-01-01

    Background: Placental abruption is one of the most common causes of bleeding during pregnancy. Multiple factors are known to be associated with increase of risk of placental abruption such as alcohol, cocaine use and cigarette smoking. The objective of this study was to identify risk factors for placental abruption in an Iranian women population. Materials and Methods: In a retrospective case - control study birth records included 78 cases with placental abruption and 780 randomly selected co...

  6. Oxygen mass transfer and hydrodynamic behaviour in wastewater: determination of local impact of surfactants by visualization techniques.

    Science.gov (United States)

    Jimenez, Mélanie; Dietrich, Nicolas; Grace, John R; Hébrard, Gilles

    2014-07-01

    Powerful techniques, based on the Planar Laser Induced Fluorescence (PLIF) technique, are deployed to locally visualize and quantify the impact of surfactants in wastewaters on hydrodynamics and oxygen mass transfer. Bubble diameter, aspect ratio, rise velocity, contamination angle, as well as flux, flux density, liquid side mass transfer and diffusion coefficients of transferred oxygen are determined based on these techniques applied in the wake of rising bubbles of diameter 1 mm and through planar gas/liquid interfaces. The initial experiments were performed in demineralized water containing small amounts of surfactant. Different concentrations of surfactant were added to finally reach the Critical Micelle Concentration (CMC). Bubbles have classically been found to be more spherical with a reduced rise velocity in the presence of surfactants up to the CMC. Above the CMC, these hydrodynamic characteristics were found to be almost constant, although the oxygen mass transfer decreased due to the presence of surfactants. Experimental results were markedly lower than predicted by the well-known Frössling equation with rigid surfaces. This is believed to be caused by a barrier of surfactants hindering the oxygen mass transfer at the interface. Similar hindrance of oxygen mass transfer applies to waters from sewage plants (filtered raw water and treated water), making accurate design of aeration tanks difficult.

  7. Time efficient way to calculate oxygen transfer areas and power input in cylindrical disposable shaken bioreactors.

    Science.gov (United States)

    Klöckner, Wolf; Lattermann, Clemens; Pursche, Franz; Büchs, Jochen; Werner, Sören; Eibl, Dieter

    2014-01-01

    Disposable orbitally shaken bioreactors are a promising alternative to stirred or wave agitated systems for mammalian and plant cell cultivation, because they provide a homogeneous and well-defined liquid distribution together with a simple and cost-efficient design. Cultivation conditions in the surface-aerated bioreactors are mainly affected by the size of the volumetric oxygen transfer area (a) and the volumetric power input (P∕VL ) that both result from the liquid distribution during shaking. Since Computational Fluid Dynamics (CFD)-commonly applied to simulate the liquid distribution in such bioreactors-needs high computing power, this technique is poorly suited to investigate the influence of many different operating conditions in various scales. Thus, the aim of this paper is to introduce a new mathematical model for calculating the values of a and P∕VL for liquids with water-like viscosities. The model equations were derived from the balance of centrifugal and gravitational forces exerted during shaking. A good agreement was found among calculated values for a and P∕VL , CFD simulation values and empirical results. The newly proposed model enables a time efficient way to calculate the oxygen transfer areas and power input for various shaking frequencies, filling volumes and shaking and reactor diameters. All these parameters can be calculated fast and with little computing power.

  8. A conceptual design of catalytic gasification fuel cell hybrid power plant with oxygen transfer membrane

    Science.gov (United States)

    Shi, Wangying; Han, Minfang

    2017-09-01

    A hybrid power generation system integrating catalytic gasification, solid oxide fuel cell (SOFC), oxygen transfer membrane (OTM) and gas turbine (GT) is established and system energy analysis is performed. In this work, the catalytic gasifier uses steam, recycled anode off-gas and pure oxygen from OTM system to gasify coal, and heated by hot cathode off-gas at the same time. A zero-dimension SOFC model is applied and verified by fitting experimental data. Thermodynamic analysis is performed to investigate the integrated system performance, and system sensitivities on anode off-gas back flow ratio, SOFC fuel utilization, temperature and pressure are discussed. Main conclusions are as follows: (1) System overall electricity efficiency reaches 60.7%(HHV) while the gasifier operates at 700 °C and SOFC at 850 °C with system pressure at 3.04 bar; (2) oxygen enriched combustion simplify the carbon-dioxide capture process, which derives CO2 of 99.2% purity, but results in a penalty of 6.7% on system electricity efficiency; (3) with SOFC fuel utilization or temperature increasing, the power output of SOFC increases while GT power output decreases, and increasing system pressure can improve both the performance of SOFC and GT.

  9. Dissolved oxygen transfer to sediments by sweep and eject motions in aquatic environments

    Science.gov (United States)

    O'Connor, B.L.; Hondzo, Miki

    2008-01-01

    Dissolved oxygen (DO) concentrations were quantified near the sediment-water interface to evaluate DO transfer to sediments in a laboratory recirculating flume and open channel under varying fluid-flow conditions. DO concentration fluctuations were observed within the diffusive sublayer, as defined by the time-averaged DO concentration gradient near the sediment-water interface. Evaluation of the DO concentration fluctuations along with detailed fluid-flow characterizations were used to quantify quasi-periodic sweep and eject motions (bursting events) near the sediments. Bursting events dominated the Reynolds shear stresses responsible for momentum and mass fluctuations near the sediment bed. Two independent methods for detecting bursting events using DO concentration and velocity data produced consistent results. The average time between bursting events was scaled with wall variables and was incorporated into a similarity model to describe the dimensionless mass transfer coefficient (Sherwood number, Sh) in terms of the Reynolds number, Re, and Schmidt number, Sc, which described transport in the flow. The scaling of bursting events was employed with the similarity model to quantify DO transfer to sediments and results showed a high degree of agreement with experimental data. ?? 2008, by the American Society of Limnology and Oceanography, Inc.

  10. Electrocatalysis of anodic oxygen-transfer reactions at modified lead dioxide electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Hsiao, Yun-Lin.

    1990-09-21

    The electrocatalytic activities were compared for pure and chloride-doped beta-PbO{sub 2} (Cl-PbO{sub 2}) films on gold and platinum substrates. Rate constants were increased significantly for oxidations of Mn{sup 2+}, toluene, benzyl alcohol, dimethylsulphoxide (DMSO) and benzaldehyde in acidic media by the incorporation of Cl{sup {minus}} into the oxide films. These reactions are concluded to occur by the electrocatalytic transfer of oxygen from H{sub 2}O to the reaction products. Results of x-ray diffraction studies indicate the Cl-PbO{sub 2} film continues to have the slightly distorted rutile structure of pure beta-PbO{sub 2}. The observed electrocatalytic phenomena are concluded to be the beneficial consequence of surface defects generated when Cl{sup {minus}} serves for charge compensation within the surface matrix and, thereby, increases the number of surface sites capable of adsorbing hydroxyl radicals which are transferred in the electrocatalytic O-transfer reactions. 91 refs., 44 figs., 10 tabs.

  11. Effect of mass transfer on the oxygen reduction reaction catalyzed by platinum dendrimer encapsulated nanoparticles.

    Science.gov (United States)

    Dumitrescu, Ioana; Crooks, Richard M

    2012-07-17

    Here we report on the effect of the mass transfer rate (k(t)) on the oxygen reduction reaction (ORR) catalyzed by Pt dendrimer-encapsulated nanoparticles (DENs) comprised of 147 and 55 atoms (Pt(147) and Pt(55)). The experiments were carried out using a dual-electrode microelectrochemical device, which enables the study of the ORR under high k(t) conditions with simultaneous detection of H(2)O(2). At low k(t) (0.02 to 0.12 cm s(-1)) the effective number of electrons involved in ORR, n(eff), is 3.7 for Pt(147) and 3.4 for Pt(55). As k(t) is increased, the mass-transfer-limited current for the ORR becomes significantly lower than the value predicted by the Levich equation for a 4-electron process regardless of catalyst size. However, the percentage of H(2)O(2) detected remains constant, such that n(eff) barely changes over the entire k(t) range explored (0.02 cm s(-1)). This suggests that mass transfer does not affect n(eff), which has implications for the mechanism of the ORR on Pt nanoparticles. Interestingly, there is a significant difference in n(eff) for the two sizes of Pt DENs (n(eff) = 3.7 and 3.5 for Pt(147) and Pt(55), respectively) that cannot be assigned to mass transfer effects and that we therefore attribute to a particle size effect.

  12. A direct electron transfer-based glucose/oxygen biofuel cell operating in human serum

    Energy Technology Data Exchange (ETDEWEB)

    Coman, V.; Gorton, L. [Department of Analytical Chemistry/Biochemistry, Lund University, 22100 Lund (Sweden); Ludwig, R. [Research Centre Applied Biocatalysis, 8010 Graz (Austria); Department of Food Sciences and Technology, BOKU-University of Natural Resources and Applied Life Sciences, 1190 Wien (Austria); Harreither, W.; Haltrich, D. [Department of Food Sciences and Technology, BOKU-University of Natural Resources and Applied Life Sciences, 1190 Wien (Austria); Ruzgas, T. [Biomedical Laboratory Science, Health and Society, Malmoe University, 20506 Malmoe (Sweden); Laboratory of Chemical Enzymology, A.N. Bach Institute of Biochemistry, 119071 Moscow (Russian Federation); Shleev, S.

    2010-02-15

    We report on the fabrication and characterisation of the very first direct electron transfer-based glucose/oxygen biofuel cell (BFC) operating in neutral glucose-containing buffer and human serum. Corynascus thermophilus cellobiose dehydrogenase and Myrothecium verrucaria bilirubin oxidase were used as anodic and cathodic bioelements, respectively. The following characteristics of the mediator-, separator- and membrane-less, a priori, non-toxic and simple miniature BFC, was obtained: an open-circuit voltage of 0.62 and 0.58 V, a maximum power density of ca. 3 and 4 {mu}W cm{sup -2} at 0.37 and 0.19 V of cell voltage, in phosphate buffer and human serum, respectively. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  13. The effect of bubble plume on oxygen transfer for moving bed biofilm reactor

    Institute of Scientific and Technical Information of China (English)

    CHENG Wen; LIU Hu; WANG Meng; WANG Min

    2014-01-01

    The movement of the bubble plume plays an important role in the operation of a moving bed biofilm reactor (MBBR), and it directly affects the contact and the mixture of the gas-liquid-solid phases in the aeration tank and also the oxygen transfer from the gas phase to the liquid phase. In this study, the velocity field is determined by a 4-frame PTV as well as the time-averaged and time- dependent velocity distributions. The velocity distribution of the bubble plume is analyzed to evaluate the operating efficiency of the MBBR. The results show that the aeration rate is one of the main factors that sway the velocity distribution of the bubble plumes and affect the operating efficiency of the reactor.

  14. Effect of intramolecular charge transfer on fluorescence and singlet oxygen production of phthalocyanine analogues.

    Science.gov (United States)

    Vachova, Lenka; Novakova, Veronika; Kopecky, Kamil; Miletin, Miroslav; Zimcik, Petr

    2012-10-14

    Intramolecular charge transfer (ICT) was studied on a series of magnesium, metal-free and zinc complexes of unsymmetrical tetrapyrazinoporphyrazines and tribenzopyrazinoporphyrazines bearing two dialkylamino substituents (donors) and six alkylsulfanyl or aryloxy substituents (non-donors). The dialkylamino substituents were responsible for ICT that deactivated excited states and led to considerable decrease of fluorescence and singlet oxygen quantum yields. Photophysical and photochemical properties were compared to corresponding macrocycles that do not bear any donor centers. The data showed high feasibility of ICT in the tetrapyrazinoporphyrazine macrocycle and significantly lower efficiency of this deactivation process in the tribenzopyrazinoporphyrazine type molecules. Considerable effect of non-donor peripheral substituents on ICT was also described. The results imply that tetrapyrazinoporphyrazines may be more suitable for development of new molecules investigated in applications based on ICT.

  15. New ruthenium nitrosyl pincer complexes bearing an O2 ligand. Mono-oxygen transfer.

    Science.gov (United States)

    Fogler, Eran; Efremenko, Irena; Gargir, Moti; Leitus, Gregory; Diskin-Posner, Yael; Ben-David, Yehoshoa; Martin, Jan M L; Milstein, David

    2015-03-02

    We report on Ru((II))(μ(2)-O2) nitrosyl pincer complexes that can return to their original Ru(0) state by reaction with mono-oxygen scavengers. Potential intermediates were calculated by density functional theory (DFT) and a mechanism is proposed, revealing a new type of metal-ligand cooperation consisting of activation of the O2 moiety by both the metal center and the NO ligand. Reaction of the Ru(0) nitrosyl complex 1 with O2 quantitatively yielded the crystallographically characterized Ru((II)) (μ(2)-O2) nitrosyl complex 2. Reaction of 2 with the mono-oxygen scavengers phosphines or CO gave the Ru(0) complex 1 and phosphine oxides, or the carbonyl complex 3 (1 trapped by CO) and CO2, respectively. Reaction of 2 with 1 equiv of phosphine at room temperature or -40 °C resulted in immediate formation of half an equivalent of 1 and 1 equiv of phosphine oxide, while half an equivalent of 2 remained unchanged. Overnight reaction at room temperature of 2 with excess CO (≥3 equiv) resulted in 3 and CO2 gas as the only products. Reaction of 1 with 1 equiv of mono-oxygen source (dioxirane) at -78 °C yielded the Ru((II))(μ(2)-O2) complex 2. Similarly, reaction of the Ru(0) dearomatized complex 4 with O2 led to the crystallographicaly characterized Ru((II))(μ(2)-O2) complex 5. Further reaction of 5 with mono-oxygen scavengers (phosphines or CO) led to the Ru(0) complex 4 and phosphine oxides or complex 6 (4 trapped by CO) and CO2. When instead only 1 equiv of 5 was reacted with 1 equiv of phosphine at room temperature, immediate formation of half an equivalent of 4 and 1 equiv of phosphine oxide took place, while half an equivalent of 5 remained unchanged. When 5 reacted with an excess of CO (≥3 equiv), complex 6 and CO2 gas were the only products obtained. DFT studies indicate a new mode of metal-ligand cooperation involving the nitrosyl ligand in the oxygen transfer process.

  16. Faster oxygen atom transfer catalysis with a tungsten dioxo complex than with its molybdenum analog.

    Science.gov (United States)

    Arumuganathan, T; Mayilmurugan, Ramasamy; Volpe, Manuel; Mösch-Zanetti, Nadia C

    2011-08-21

    The synthesis and characterization of a series of molybdenum ([MoO(2)Cl(L(n))]; L(1) (1), L(2) (3)) and tungsten ([WO(2)Cl(L(n))]; L(1) (2), L(2) (4)) dioxo complexes (L(1) = 1-methyl-4-(2-hydroxybenzyl)-1,4-diazepane and L(2) = 1-methyl-4-(2-hydroxy-3,5-di-tert-butylbenzyl)-1,4-diazepane) of tridentate aminomonophenolate ligands HL(1) and HL(2) are reported. The ligands were obtained by reductive amination of 1-methyl-1,4-diazepane with the corresponding aldehyde. Complexes 3 and 4 were obtained by the reaction of [MO(2)Cl(2)(dme)(n)] (M = Mo, n = 0; W, n = 1) with the corresponding ligand in presence of a base, whereas for the preparation of 1 and 2 the ligands were deprotonated by KH prior to the addition to the metal. They were characterized by NMR and IR spectroscopy, by cyclic voltammetry, mass spectrometry, elemental analysis and by single-crystal X-ray diffraction analysis. Solid-state structures of the molybdenum and tungsten cis-dioxo complexes reveal hexa-coordinate metal centers surrounded by two oxo groups, a chloride ligand and by the tridentate monophenolate ligand which coordinates meridionally through its [ONN] donor set. In the series of compounds 1-4, complexes 3 and 4 have been used as catalysts for the oxygen atom transfer reaction between dimethyl sulfoxide (DMSO) and trimethyl phosphine (PMe(3)). Surprisingly, faster oxygen atom transfer (OAT) reactivity has been observed for the tungsten complex [WO(2)Cl(L(2))] (4) in comparison to its molybdenum analog [MoO(2)Cl(L(2))] (3) at room temperature. The kinetic results are discussed and compared in terms of their reactivity. This journal is © The Royal Society of Chemistry 2011

  17. High cell density fed-batch fermentations for lipase production: feeding strategies and oxygen transfer.

    Science.gov (United States)

    Salehmin, M N I; Annuar, M S M; Chisti, Y

    2013-11-01

    This review is focused on the production of microbial lipases by high cell density fermentation. Lipases are among the most widely used of the enzyme catalysts. Although lipases are produced by animals and plants, industrial lipases are sourced almost exclusively from microorganisms. Many of the commercial lipases are produced using recombinant species. Microbial lipases are mostly produced by batch and fed-batch fermentation. Lipases are generally secreted by the cell into the extracellular environment. Thus, a crude preparation of lipases can be obtained by removing the microbial cells from the fermentation broth. This crude cell-free broth may be further concentrated and used as is, or lipases may be purified from it to various levels. For many large volume applications, lipases must be produced at extremely low cost. High cell density fermentation is a promising method for low-cost production: it allows a high concentration of the biomass and the enzyme to be attained rapidly and this eases the downstream recovery of the enzyme. High density fermentation enhances enzyme productivity compared with the traditional submerged culture batch fermentation. In production of enzymes, a high cell density is generally achieved through fed-batch operation, not through perfusion culture which is cumbersome. The feeding strategies used in fed-batch fermentations for producing lipases and the implications of these strategies are discussed. Most lipase-producing microbial fermentations require oxygen. Oxygen transfer in such fermentations is discussed.

  18. Gas hold-up and oxygen mass transfer in three pneumatic bioreactors operating with sugarcane bagasse suspensions.

    Science.gov (United States)

    Esperança, M N; Cunha, F M; Cerri, M O; Zangirolami, T C; Farinas, C S; Badino, A C

    2014-05-01

    Sugarcane bagasse is a low-cost and abundant by-product generated by the bioethanol industry, and is a potential substrate for cellulolytic enzyme production. The aim of this work was to evaluate the effects of air flow rate (QAIR), solids loading (%S), sugarcane bagasse type, and particle size on the gas hold-up (εG) and volumetric oxygen transfer coefficient (kLa) in three different pneumatic bioreactors, using response surface methodology. Concentric tube airlift (CTA), split-cylinder airlift (SCA), and bubble column (BC) bioreactor types were tested. QAIR and %S affected oxygen mass transfer positively and negatively, respectively, while sugarcane bagasse type and particle size (within the range studied) did not influence kLa. Using large particles of untreated sugarcane bagasse, the loop-type bioreactors (CTA and SCA) exhibited higher mass transfer, compared to the BC reactor. At higher %S, SCA presented a higher kLa value (0.0448 s−1) than CTA, and the best operational conditions in terms of oxygen mass transfer were achieved for %S 27.0 L min−1. These results demonstrated that pneumatic bioreactors can provide elevated oxygen transfer in the presence of vegetal biomass, making them an excellent option for use in three-phase systems for cellulolytic enzyme production by filamentous fungi.

  19. Cloned pigs derived from somatic cell nuclear transfer embryos cultured in vitro at low oxygen tension

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Pig cloning has great potential to human xenotransplantation. The present study was designed to establish a more efficient system for producing cloned pigs by somatic cell nuclear transfer (SCNT). Our approach was as follows: SCNT embryos were reconstructed by using fetal fibroblasts of Chinese miniature pig as donors and in vitro matured oocytes of prepubertal gilts as recipients. Reconstructed embryos were induced by electrical fusion/activation and cultured in BSA-containing North Carolina State University 23 medium (NCSU-23) or Porcine Zygote Medium (PZM-3) at the gas condition of 5% CO2, 7% O2, 88% N2. A total of 230 cloned embryos were transferred to three surrogate sows, producing three piglets. One of them is apparently healthy. The clonal provenance of the piglet was indicated by its coat color and confirmed by DNA microsatellite analysis. These results indicate that the use of in vitro matured oocytes from prepubertal gilts as recipient, combined with cloned embryos cultured at low oxygen tension is an effective way to produce cloned pigs.

  20. Hyperspherical elliptic coordinates treatment of muon transfer from muonic hydrogen to atomic oxygen

    CERN Document Server

    Dupays, A; Beswick, J A; Rizzo, C; Bakalov, D; Dupays, Arnaud; Lepetit, Bruno; Rizzo, Carlo; Bakalov, Dimitar

    2003-01-01

    Quantum-mechanical calculations of muon transfer between muonic hydrogen and an oxygen nuclei for $s$ waves and collision energies in the range $10^{-3} - 10^3$ eV, are presented. Close-coupling time-independent Schr\\"odinger equations, written in terms of hyperspherical elliptic coordinates were integrated along the hyper-radius to obtain the partial and total muon-transfer probabilities. The results show the expected Wigner-Bethe threshold behavior up to collision energies of the order of $10^{-2}$ eV and pronounced maxima at $10^2$ eV which can be interpreted in terms of crossings between potential energy curves corresponding to the entrance channel state $(\\mu p)_{1s} + \\mO$ and two product channels which asymptotically correlate to $p + (\\mO\\mu)_{n=5,6}$. The population of the final states with different orbital angular momenta is found to be essentially independent of energy in the range considered in this work. This can be attributed to a strong selection rule for the conservation of the quantum number...

  1. Mammary excretion and placental transfer of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolane] platinum(II) in rats.

    Science.gov (United States)

    Cho, Y B; Kim, K H; Kim, D K; Miyamoto, G

    1996-09-01

    The mammary excretion and placental transfer of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolan e] platinum(II) (CAS 146665-77-2, SKI 2053R), a new potential anticancer agent, were investigated in the lactating or pregnant rats after a single intravenous administration of 14C-SKI 2053R (20 mg/kg, 100 microCi/kg). The radioactivity of the milk declined in a biexponential fashion with an initial half-life of 0.39 h and with a terminal half-life of 14.05 h in the lactating rats. The radioactivity of the milk was lower than that of plasma until 1 h after dosing, but was higher than that of plasma from 4 h after dosing. 14C-SKI 2053R was well distributed to most tissues including uterus and placenta in the pregnant rats, but the levels of radioactivity in the amniotic fluid and fetuses were markedly lower than that in the maternal plasma. Therefore, it is concluded that SKI 2053R scarcely passes the blood-placenta barrier, which was confirmed by the whole-body autoradiography study.

  2. Placental Origins of Adverse Pregnancy Outcomes: Potential Molecular Targets- An Executive Workshop Summary of the Eunice Kennedy Shriver National Institute of Child Health and Human Development

    Science.gov (United States)

    Ilekis, John V.; Tsilou, Ekaterini; Fisher, Susan; Abrahams, Vikki M.; Soares, Michael J.; Cross, James C.; Zamudio, Stacy; Illsley, Nicholas P.; Myatt, Leslie; Colvis, Christine; Costantine, Maged M.; Haas, David M.; Sadovsky, Yoel; Weiner, Carl; Rytting, Erik; Bidwell, Gene

    2016-01-01

    Although much progress is being made in understanding the molecular pathways in the placenta involved in the pathophysiology of pregnancy related disorders, a significant gap exists in utilizing this information for developing new drug therapies to improve pregnancy outcome. On March 5–6, 2015, the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health sponsored a two day workshop titled Placental Origins of Adverse Pregnancy Outcomes: Potential Molecular Targets to begin to address this gap. Particular emphasis was given in the identification of important molecular pathways that could serve as drug targets and the advantages and disadvantages of targeting these particular pathways. This article is a summary of the proceedings of this workshop. A broad number of topics were covered ranging from basic placental biology to clinical trials. This included research in the basic biology of placentation, such as trophoblast migration and spiral artery remodeling, and trophoblast sensing and response to infectious and non-infectious agents. Research findings in these areas will be critical for formulating developing future treatments and developing therapies for the prevention of a number of pregnancy disorders of placental origin including preeclampsia, fetal growth restriction, and uterine inflammation. Research was also presented summarizing ongoing clinical efforts in the U.S. and in Europe testing novel interventions for preeclampsia and fetal growth restriction, including agents such as oral arginine supplementation, sildenafil, pravastatin, gene therapy using virally-delivered vascular endothelial growth factor, and oxygen supplementation therapy. Strategies were also proposed to improve fetal growth by enhancing nutrient transport to the fetus by modulating their placental transporters, as well as targeting placental mitochondrial dysfunction and oxidative stress to improve placental health. The roles

  3. Placental apoptosis in recurrent miscarriage

    Directory of Open Access Journals (Sweden)

    Tarek A. Atia

    2017-09-01

    Full Text Available Apoptosis is an interactive and dynamic biological process involved in all phases of embryogenesis. We aimed to study the effect of placental apoptosis on recurrent miscarriage (RM. Placental tissue samples were collected from 40 women with RM (study group and 30 women with sporadic spontaneous abortion (control group. Samples were prepared and stained immunohistochemically with markers for both the apoptotic protein (p53 and anti-apoptotic Bcl-2 antibodies. Our results showed that expression of the apoptotic (p53 protein was significantly increased in the placental tissues of the RM group (p = 0.003. By contrast, the expression of anti-apoptotic (Bcl-2 antibodies was significantly increased in the placental tissues of the control group (p = 0.025. We concluded that placental apoptosis plays a crucial role in pregnancy continuation. However, increased p53 expression in placental tissue in early pregnancy could negatively affect pregnancy continuation.

  4. Optimization of perfluorocarbon emulsion properties for enhancing oxygen mass transfer in a bio-artificial liver support system

    CSIR Research Space (South Africa)

    Moolman, FS

    2004-07-29

    Full Text Available : With increase in the dispersed phase volume fraction (phi(p)) both the oxygen holding capacity and the viscosity increases. These issues are addressed here using simplified mass transfer models, amenable to analytical solution, for both gas-sparged and membrane...

  5. Oxidation of ferrous nitrilotriacetic acid with oxygen : A model for oxygen mass transfer parallel to reaction kinetics

    NARCIS (Netherlands)

    Demmink, JF; Beenackers, AACM

    1997-01-01

    The kinetics of the reaction of ferrous chelate of nitrilotriacetic acid (NTA) and gaseous oxygen were studied in a stirred-cell reactor. The initial concentration of ferrous chelate was 0.100 kmol/m(3). Other reaction conditions include 293

  6. Oxidation of ferrous nitrilotriacetic acid with oxygen : A model for oxygen mass transfer parallel to reaction kinetics

    NARCIS (Netherlands)

    Demmink, J.F; Beenackers, A.A C M

    1997-01-01

    The kinetics of the reaction of ferrous chelate of nitrilotriacetic acid (NTA) and gaseous oxygen were studied in a stirred-cell reactor. The initial concentration of ferrous chelate was 0.100 kmol/m(3). Other reaction conditions include 293

  7. Enhanced kinetics of hole transfer and electrocatalysis during photocatalytic oxygen evolution by cocatalyst tuning

    KAUST Repository

    Nurlaela, Ela

    2016-05-23

    Understanding photophysical and electrocatalytic processes during photocatalysis in a powder suspension system is crucial for developing efficient solar energy conversion systems. We report a substantial enhancement by a factor of 3 in photocatalytic effi-ciency for the oxygen evolution reaction (OER) by adding trace amounts (~0.05 wt%) of noble metals (Rh or Ru) to a 2 wt% cobalt oxide-modified Ta3N5 photocatalyst particulate. The optimized system exhibited high quantum efficiencies (QEs) of up to 28 and 8.4% at 500 and 600 nm in 0.1 M Na2S2O8 at pH 14. By isolating the electrochemical components to generate doped cobalt oxide electrodes, the electrocatalytic activity of cobalt oxide when doped with Ru or Rh was improved compared with cobalt oxide, as evidenced by the onset shift for electrochemical OER. Density functional theory (DFT) calculation shows that the ef-fects of a second metal addition perturbs the electronic structure and redox properties in such a way that both hole transfer kinetics and electrocatalytic rates improve. Time resolved terahertz spectroscopy (TRTS) measurement provides evidence of long-lived electron populations (>1 ns; with mobilities μe ~0.1-3 cm2 V-1 s-1), which are not perturbed by the addition of CoOx-related phases. Furthermore, we find that Ta3N5 phases alone suffer ultrafast hole trapping (within 10 ps); the CoOx and M-CoOx decorations most likely induce a kinetic competition between hole transfer toward the CoOx-related phases and trapping in the Ta3N5 phase, which is consistent with the improved OER rates. The present work not only provides a novel way to improve electrocatalytic and photocatalytic performance but also gives additional tools and insight to understand the characteristics of photocatalysts that can be used in a suspension system.

  8. Lateral transfer of tetrahymanol-synthesizing genes has allowed multiple diverse eukaryote lineages to independently adapt to environments without oxygen

    Directory of Open Access Journals (Sweden)

    Takishita Kiyotaka

    2012-02-01

    Full Text Available Abstract Sterols are key components of eukaryotic cellular membranes that are synthesized by multi-enzyme pathways that require molecular oxygen. Because prokaryotes fundamentally lack sterols, it is unclear how the vast diversity of bacterivorous eukaryotes that inhabit hypoxic environments obtain, or synthesize, sterols. Here we show that tetrahymanol, a triterpenoid that does not require molecular oxygen for its biosynthesis, likely functions as a surrogate of sterol in eukaryotes inhabiting oxygen-poor environments. Genes encoding the tetrahymanol synthesizing enzyme squalene-tetrahymanol cyclase were found from several phylogenetically diverged eukaryotes that live in oxygen-poor environments and appear to have been laterally transferred among such eukaryotes. Reviewers This article was reviewed by Eric Bapteste and Eugene Koonin.

  9. Metallized Gelled Propellants: Oxygen/RP-1/Aluminum Rocket Heat Transfer and Combustion Measurements

    Science.gov (United States)

    Palaszewski, Bryan; Zakany, James S.

    1996-01-01

    A series of rocket engine heat transfer experiments using metallized gelled liquid propellants was conducted. These experiments used a small 20- to 40-lb/f thrust engine composed of a modular injector, igniter, chamber and nozzle. The fuels used were traditional liquid RP-1 and gelled RP-1 with 0-, 5-, and 55-percentage by weight loadings of aluminum particles. Gaseous oxygen was used as the oxidizer. Three different injectors were used during the testing: one for the baseline O(2)/RP-1 tests and two for the gelled and metallized gelled fuel firings. Heat transfer measurements were made with a rocket engine calorimeter chamber and nozzle with a total of 31 cooling channels. Each chamber used a water flow to carry heat away from the chamber and the attached thermocouples and flow meters allowed heat flux estimates at each of the 31 stations. The rocket engine Cstar efficiency for the RP-1 fuel was in the 65-69 percent range, while the gelled 0 percent by weight RP-1 and the 5-percent by weight RP-1 exhibited a Cstar efficiency range of 60 to 62% and 65 to 67%, respectively. The 55-percent by weight RP-1 fuel delivered a 42-47% Cstar efficiency. Comparisons of the heat flux and temperature profiles of the RP-1 and the metallized gelled RP-1/A1 fuels show that the peak nozzle heat fluxes with the metallized gelled O2/RP-1/A1 propellants are substantially higher than the baseline O2/RP-1: up to double the flux for the 55 percent by weight RP-1/A1 over the RP-1 fuel. Analyses showed that the heat transfer to the wall was significantly different for the RP-1/A1 at 55-percent by weight versus the RP-1 fuel. Also, a gellant and an aluminum combustion delay was inferred in the 0 percent and 5-percent by weight RP-1/A1 cases from the decrease in heat flux in the first part of the chamber. A large decrease in heat flux in the last half of the chamber was caused by fuel deposition in the chamber and nozzle. The engine combustion occurred well downstream of the injector face

  10. Oxygen atom transfer reactions from Mimoun complexes to sulfides and sulfoxides. A bonding evolution theory analysis.

    Science.gov (United States)

    González-Navarrete, Patricio; Sensato, Fabricio R; Andrés, Juan; Longo, Elson

    2014-08-07

    In this research, a comprehensive theoretical investigation has been conducted on oxygen atom transfer (OAT) reactions from Mimoun complexes to sulfides and sulfoxides. The joint use of the electron localization function (ELF) and Thom's catastrophe theory (CT) provides a powerful tool to analyze the evolution of chemical events along a reaction pathway. The progress of the reaction has been monitored by structural stability domains from ELF topology while the changes between them are controlled by turning points derived from CT which reveal that the reaction mechanism can be separated in several steps: first, a rupture of the peroxo O1-O2 bond, then a rearrangement of lone pairs of the sulfur atom occurs and subsequently the formation of S-O1 bond. The OAT process involving the oxidation of sulfides and sulfoxides is found to be an asynchronous process where O1-O2 bond breaking and S-O1 bond formation processes do not occur simultaneously. Nucleophilic/electrophilic characters of both dimethyl sulfide and dimethyl sulfoxide, respectively, are sufficiently described by our results, which hold the key to unprecedented insight into the mapping of electrons that compose the bonds while the bonds change.

  11. Formation of cysteine sulfenic acid by oxygen atom transfer from nitrite.

    Science.gov (United States)

    Heinecke, Julie; Ford, Peter C

    2010-07-14

    Cysteine sulfenic acid CysS(O)H is shown to be formed for the reaction of cysteine (CysSH) with aqueous nitrite and the water-soluble ferriheme models Fe(III)(TPPS) (TPPS = meso-tetra(4-sulfonatophenyl)porphyrinato) or Fe(III)(TMPS) (TMPS = meso-tetra(sulfonatomesityl)porphyrinato) at pH 5.8 and 7.4. The other product is the respective ferrous nitrosyl complex Fe(II)(Por)(NO) (Por = TPPS or TMPS). Analogous oxygen atom transfers (OAT) were seen when glutathione (GSH) was used as the substrate. The sulfenic acids, CysS(O)H and GS(O)H, are transient species since they react rapidly with excess thiol to give the respective disulfides, so their presence as reactive intermediates was demonstrated by trapping with dimedone and detecting the resulting adduct using LC/MS. Preliminary kinetics studies are consistent with rate-limiting OAT from a ferric nitro complex Fe(III)(Por)(NO(2)(-)) to CysSH, although this reaction is complicated by a competing dead-end equilibrium to form the thiolate complex (Fe(III)(TPPS)(CysS(-)).

  12. The surrounding tissue modifies the placental stem villous vascular responses

    DEFF Research Database (Denmark)

    Brøgger, Torbjørn; Forman, Axel; Aalkjær, Christian;

    2014-01-01

    Background: The placenta is the base for the exchange of nutrients, oxygen and waste products for the fetus. The placental vessels hold a crucial role in regulation of blood flow, and compromised function may lead to complications like growth retardation and preeclampsia where no specific treatment...... is available. In-depth understanding of the mechanisms involved in control of placental vascular tone are needed to develop new tissue targets for therapeutic intervention. Method: From fresh born placentas segments of stem villous arteries were carefully dissected. The artery branches were divided...

  13. Oxygen transport membrane system and method for transferring heat to catalytic/process reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Sean M.; Kromer, Brian R.; Litwin, Michael M.; Rosen, Lee J.; Christie, Gervase Maxwell; Wilson, Jamie R.; Kosowski, Lawrence W.; Robinson, Charles

    2016-01-19

    A method and apparatus for producing heat used in a synthesis gas production process is provided. The disclosed method and apparatus include a plurality of tubular oxygen transport membrane elements adapted to separate oxygen from an oxygen containing stream contacting the retentate side of the membrane elements. The permeated oxygen is combusted with a hydrogen containing synthesis gas stream contacting the permeate side of the tubular oxygen transport membrane elements thereby generating a reaction product stream and radiant heat. The present method and apparatus also includes at least one catalytic reactor containing a catalyst to promote the steam reforming reaction wherein the catalytic reactor is surrounded by the plurality of tubular oxygen transport membrane elements. The view factor between the catalytic reactor and the plurality of tubular oxygen transport membrane elements radiating heat to the catalytic reactor is greater than or equal to 0.5

  14. Oxygen transport membrane system and method for transferring heat to catalytic/process reactors

    Science.gov (United States)

    Kelly, Sean M; Kromer, Brian R; Litwin, Michael M; Rosen, Lee J; Christie, Gervase Maxwell; Wilson, Jamie R; Kosowski, Lawrence W; Robinson, Charles

    2014-01-07

    A method and apparatus for producing heat used in a synthesis gas production is provided. The disclosed method and apparatus include a plurality of tubular oxygen transport membrane elements adapted to separate oxygen from an oxygen containing stream contacting the retentate side of the membrane elements. The permeated oxygen is combusted with a hydrogen containing synthesis gas stream contacting the permeate side of the tubular oxygen transport membrane elements thereby generating a reaction product stream and radiant heat. The present method and apparatus also includes at least one catalytic reactor containing a catalyst to promote the stream reforming reaction wherein the catalytic reactor is surrounded by the plurality of tubular oxygen transport membrane elements. The view factor between the catalytic reactor and the plurality of tubular oxygen transport membrane elements radiating heat to the catalytic reactor is greater than or equal to 0.5.

  15. Non-placental causes of intrauterine growth restriction.

    Science.gov (United States)

    Hendrix, Nancy; Berghella, Vincenzo

    2008-06-01

    Placental insufficiency, in some form or fashion, is associated with the majority of cases of intrauterine growth restriction (IUGR). There are numerous causes of IUGR which are not caused primarily by placental insufficiency, but indirectly lead to it. The causes of IUGR can be subdivided into fetal and maternal etiologies. The fetal etiologies consist of genetic diseases, congenital malformations, infections, multiple gestations, and placental/cord abnormalities. The maternal etiologies are categorized as follows: (1) decreased uteroplacental blood flow, (2) reduced blood volume, (3) decreased oxygen carrying capacity, (4) nutrition status, (5) teratogens, and (6) miscellaneous causes such as short interpregnancy intervals, race, maternal age, and low socioeconomic status. Knowledge of the etiologies of fetal growth restriction is essential, so that future care can be targeted at prevention. There are several primary and secondary prevention strategies that can be adopted.

  16. Clinical use of placental hormones in pregnancy management.

    Science.gov (United States)

    De Bonis, M; Vellucci, F L; Di Tommaso, M; Voltolini, C; Torricelli, M; Petraglia, F

    2012-09-01

    Across human pregnancy, placenta represents a transit of oxygen and nutrients from the mother to the fetus and actively produces a large number of hormones that serve to regulate and balance maternal and fetal physiology. An abnormal secretion of placental hormones may be part of the pathogenesis of the main obstetric syndrome, from early to late pregnancy, in particular chromosomopathies, miscarriage, gestational trophoblastic diseases, preeclampsia, gestational diabetes, and pre-term delivery. The possibility to measure placental hormones represents an important tool not only for the diagnosis and management of gestational disorders, but it is also fundamental in the early identification of women at risk for these pregnancy complications. In the last decades, the use of ultrasound examination has provided additional biophysical markers, improving the early diagnosis of gestational diseases. In conclusion, while few placental hormones have sufficient sensitivity for clinical application, there are promising new biochemical and biophysical markers that, if used in combination, may provide a valid screening tool.

  17. Singlet oxygen triplet energy transfer-based imaging technology for mapping protein-protein proximity in intact cells.

    Science.gov (United States)

    To, Tsz-Leung; Fadul, Michael J; Shu, Xiaokun

    2014-01-01

    Many cellular processes are carried out by large protein complexes that can span several tens of nanometres. Whereas forster resonance energy transfer has a detection range of technology with a detection range of up to several tens of nanometres: singlet oxygen triplet energy transfer. We demonstrate that our method confirms the topology of a large protein complex in intact cells, which spans from the endoplasmic reticulum to the outer mitochondrial membrane and the matrix. This new method is thus suited for mapping protein proximity in large protein complexes.

  18. Risk factors of placental abruption

    Directory of Open Access Journals (Sweden)

    Hooria Seyedhosseini Ghaheh

    2013-01-01

    Full Text Available Background: Placental abruption is one of the most common causes of bleeding during pregnancy. Multiple factors are known to be associated with increase of risk of placental abruption such as alcohol, cocaine use and cigarette smoking. The objective of this study was to identify risk factors for placental abruption in an Iranian women population. Materials and Methods: In a retrospective case - control study birth records included 78 cases with placental abruption and 780 randomly selected controls were investigated. Statistical analysis for comparing the studied risk factors between groups was performed using Pearson ′ s Chi-square test along with presenting relevant odds ratio (OR. Results: From 7301 deliveries included in the study, 78 (1% was complicated placental abruption. Women aged 35 or more likely for experiencing (OR = 3.650, 95% confidence interval [CL] = 1.57-6.83 and those who had a previous cesarean section (OR = 2.65, 95% CL = 3.91- 33.41 were in higher risk for placental abruption ([50 cases] 64% vs. [28 cases] 36% P < 0.01. Conclusion: The results indicate that among the placental abruption is one of the most common causes of bleeding during the pregnancy and one of the major obstetrical emergency.

  19. Risk factors of placental abruption

    Science.gov (United States)

    Ghaheh, Hooria Seyedhosseini; Feizi, Awat; Mousavi, Maryam; Sohrabi, Davood; Mesghari, Leila; Hosseini, Zahra

    2013-01-01

    Background: Placental abruption is one of the most common causes of bleeding during pregnancy. Multiple factors are known to be associated with increase of risk of placental abruption such as alcohol, cocaine use and cigarette smoking. The objective of this study was to identify risk factors for placental abruption in an Iranian women population. Materials and Methods: In a retrospective case – control study birth records included 78 cases with placental abruption and 780 randomly selected controls were investigated. Statistical analysis for comparing the studied risk factors between groups was performed using Pearson's Chi-square test along with presenting relevant odds ratio (OR). Results: From 7301 deliveries included in the study, 78 (1%) was complicated placental abruption. Women aged 35 or more likely for experiencing (OR = 3.650, 95% confidence interval [CL] = 1.57-6.83) and those who had a previous cesarean section (OR = 2.65, 95% CL = 3.91- 33.41) were in higher risk for placental abruption ([50 cases] 64% vs. [28 cases] 36% P < 0.01). Conclusion: The results indicate that among the placental abruption is one of the most common causes of bleeding during the pregnancy and one of the major obstetrical emergency. PMID:24174950

  20. Regional changes of placental vascularization in preeclampsia: a review.

    Science.gov (United States)

    Sahay, Akriti S; Sundrani, Deepali P; Joshi, Sadhana R

    2015-08-01

    Preeclampsia is characterized by vascular dysfunction and results in maternal and fetal morbidity and mortality. The placenta plays a critical role in the growth and development of the fetus, and recent studies indicate that placental architecture, oxygen availability, and oxidative stress indices vary across different regions of the placenta. Our earlier studies have reported altered maternal angiogenesis and differential placental gene expression and methylation patterns of angiogenic factors in women with preeclampsia when compared with normotensive women. We have also demonstrated lower maternal and placental neurotrophin (NT) levels in women with preeclampsia. Studies suggest that oxidative stress is associated with proteases like matrix metalloproteinases (MMPs) and growth factors like NTs and angiogenic factors known to be involved in the process of angiogenesis. Recently, we have reported regionwise differential oxidative stress, antioxidant enzyme activity, and NT levels in placenta from normotensive control women and women with preeclampsia. The current review describes the regional changes in the placenta and highlights the role of placental oxidative stress in influencing regional differences in the expression of angiogenic factors, MMPs, and NTs. This review discusses the need for further research on various growth factors and proteins involved in the process of placental development across different regions of the placenta. This would help to understand whether regional differences in these factors affect the growth and development of the fetus.

  1. Placental perfusion - a human alternative

    DEFF Research Database (Denmark)

    Mose, Tina; Knudsen, Lisbeth E

    2006-01-01

    Foetal exposures to environmental and medicinal products have impact on the growth of the foetus (e.g. cigarette smoke) and development of organs (e.g. methylmercury and Thalidomide). Perfusion studies of the human term placenta enable investigation of placental transport of chemical substances...... between the mother and foetus. Dual perfusion of a single cotyledon in the human placenta can contribute to a better understanding of the placental barrier, transport rate and mechanisms of different substances and placental metabolism. The perfusion system has recently been established in Copenhagen...

  2. Prediction of Oxygen Mass Transfer Coefficients in Stirred Bioreactor with Rushton Turbine Impeller for Simulated (Non-Microbial Medias

    Directory of Open Access Journals (Sweden)

    Ameel Mohammed Rahman Al-Mayah

    2014-06-01

    Full Text Available The study of oxygen mass transfer was conducted in a laboratory scale 5 liter stirred bioreactor equipped with one Rushton turbine impeller. The effects of superficial gas velocity, impeller speed, power input and liquid viscosity on the oxygen mass transfer were considered. Air/ water and air/CMC systems were used as a liquid media for this study. The concentration of CMC was ranging from 0.5 to 3 w/v. The experimental results show that volumetric oxygen mass transfer coefficient increases with the increase in the superficial gas velocity and impeller speed and decreases with increasing liquid viscosity. The experimental results of kla were correlated with a mathematical correlation describing the influences of the considered factors (the overall power input and the superficial gas velocity over the studied rages. The predicted kla values give acceptable results compared with the experimental values. The following correlations were obtained: Air/water system Air/CMC system (0.5w/v Air/CMC system (1w/v Air/CMC system (2w/v Air/CMC system (3w/v

  3. Adaptation of the "Dynamic Method" for measuring the specific respiration rate in oxygen transfer systems through diffusion membrane.

    Science.gov (United States)

    Pamboukian, Marilena Martins; Pereira, Carlos Augusto; Augusto, Elisabeth de Fatima Pires; Tonso, Aldo

    2011-12-01

    Monitoring the specific respiration rate (Q(O2)) is a valuable tool to evaluate cell growth and physiology. However, for low Q(O2) values the accuracy may depend on the measurement methodology, as it is the case in animal cell culture. The widely used "Dynamic Method" imposes serious difficulties concerning oxygen transfer cancellation, especially through membrane oxygenation. This paper presents an improved procedure to this method, through an automated control of the gas inlet composition that can minimize the residual oxygen transfer driving force during the Q(O2) measurement phase. The improved technique was applied to animal cell cultivation, particularly three recombinant S2 (Drosophila melanogaster) insect cell lines grown in a membrane aeration bioreactor. The average measurements of the proposed method reached 98% of stationary liquid phase balance method, taken as a reference, compared to 21% when the traditional method was used. Furthermore, this methodology does not require knowledge of the volumetric transfer coefficient k(L)a, which may vary during growth.

  4. Transfer and consumption of oxygen during the cultivation of the ectomycorrhizal fungus Rhizopogon nigrescens in an airlift bioreactor.

    Science.gov (United States)

    Rossi, Márcio José; Nascimento, Francisco Xavier; Giachini, Admir José; Oliveira, Vetúria Lopes; Furigo, Agenor

    2017-02-01

    The study had the objective of examining the aspects involved in the cultivation of ectomycorrhizal fungi for the production of commercially sustainable inoculant to attend the demands of the seedling nursery industry. It focused on certain parameters, such as the oxygen consumption levels, during the cultivation of the ectomycorrhizal fungus Rhizopogon nigrescens CBMAI 1472, which was performed in a 5-L airlift bioreactor. The dynamic method was employed to determine the volumetric coefficient for the oxygen transfer (k L a) and the specific oxygen uptake rate (Q O2 ). The results indicate that specific growth rates (μ X ) and oxygen consumption decline rapidly with time, affected mainly by increases in biomass concentration (X). Increases in X are obtained primarily by increases in the size of pellets that are formed, altering, consequently, the cultivation dynamics. This is the result of natural increases in transferring resistance that are observed in these environments. Therefore, to avoid critical conditions that affect viability and the productivity of the process, particular settings are discussed.

  5. Theoretical Studies of Oxygen Reduction and Proton Transfer in SOFCs and Nerve Agents on Selected Surfaces

    Science.gov (United States)

    2015-11-19

    PART A: Oxygen Reduction in SOFCs I. Computational Methods All calculations were performed in Gaussian09 suite of quantum programs. Local minimum...C TECH REPORT 2012-2014 2.1 Structure of CO4 2- , CO5 2- and carbonate clusters The structures of CO4 2- and CO5 2- were optimized at the...each picture, each alkali metal atom (M) is bonded to three carbonate oxygen atoms, while each carbonate oxygen atom is connected to two M atoms

  6. Placental Transmogrification of the lung

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Woo; Park, Il Hwan; Kwon, Woo Cheol; Eom, Min Seob; Kim, Young Ju; Hwan, Joong Hwan [Yonsei University Wonju College of Medicine, Wonju (Korea, Republic of)

    2013-12-15

    Placental transmogrification is a very rare lung disease, where the alveoli resemble the chorionic villi of placenta, and this change is a characteristic finding. A 31-year-old female patient presented with cough and dyspnea that had begun 2 weeks prior to admission. Along with giant bulla found in the left upper lung field, subsegmental consolidation was also identified in the lingular segment on plain chest radiograph and CT scan. Wedge resection was performed to remove the bulla. Pathologic examination of the resected bulla revealed destruction of the normal structures and characteristic villous and papillary changes. These changes led to a diagnosis of placental transmogrification. We made an encounter of an unusual placental transmogrification which had different image findings from other reported transmogrification cases. Thus, we report an atypical placental transmogrification case where both consolidation and giant bulla coexist.

  7. Placental abruption: a persisting killer

    Directory of Open Access Journals (Sweden)

    Shakuntala Amirchand Chhabra

    2014-06-01

    Full Text Available Background: Placental abruption, common disorder in obstetric practice, enigma too, is uniquely fraught with dangers to mother baby. Objectives of study were to study trends of placental abruption, risk factors, management strategies to learn more for reduction in morbidity-mortality of mother-baby, even with low resources, also get insight for future research. Methods: Records of cases of placental abruption managed over 27 years (between 1985 to 2011 were divided into three yearly blocks, A to I and analysed. Details including operative procedures like dilatation-curettage, Caesarean Section (CS or Ante-Partum Haemorrhage (APH in past, disorders like chronic hypertension, threatened abortion, pregnancy specific hypertension, diabetes, anaemia in index pregnancy, management done maternal-neonatal outcome were analysed using stata 6 software. Results: There were 66,459 births during analysis period with 667 cases of placental abruption, 1% births, increasing trends from, 0.73% between 1985-1987 to, 1.11% in 2009-2011. In these 667 cases of placental abruption, 211 (32.5% perinatal deaths occurred. Ratio of perinatal deaths due to placental abruption to overall perinatal deaths increased from 2.12% (8 cases between 1985-1987 (Block A to 5.12% (37 cases between 2009-2011 (Block I. Case fatality in cases of placental abruption has been fluctuating between 3 to 5% till 2004, contributing to around 12-15%, maternal mortality, with no fatality in last 7 years. Conclusions: Cases of placental abruption have been increasing with no obvious reason. In recent past maternal deaths could be prevented but perinatal deaths, have been persisting actually more in last decade. [Int J Reprod Contracept Obstet Gynecol 2014; 3(3.000: 604-609

  8. Unifying mechanism for toxicity and addiction by abused drugs: electron transfer and reactive oxygen species.

    Science.gov (United States)

    Kovacic, Peter; Cooksy, Andrew L

    2005-01-01

    Abused drugs are of grave concern throughout the world for a variety of reasons. Although impressive advances have been made, there are many unknown mechanistic aspects. This report presents a novel hypothesis based on a unifying theme for action of the major classes of abused drugs, in addition to commonly abused therapeutic drugs. The approach is based on electron transfer (ET), reactive oxygen species (ROS), and oxidative stress (OS). It is significant that physiologically active substances generally incorporate ET functionalities, either per se, or more usually in their metabolites. In order to achieve ET in vivo, the reduction potential must be more positive than -0.5 V, which is the case for metabolites of abused drugs, except for special cases. Since the ET process is catalytic, only small quantities of agent are needed for generation of large amounts of ROS during redox cycyling. Bioaction with cellular materials could entail ET alone or participation of ROS. In the abused category, among the main classes of ET functionalities are quinones and iminiums, with alpha-dicarbonyl and nitroxyl radical being rarer. Nicotine yields nicotine iminium, myosmine iminium, and DNA base iminium via alkylation by a metabolic nitrosamine. In the case of alcohol, diacetyl (an alpha-dicarbonyl) is formed, which can lead to conjugated imine (or iminium) by condensation with pri-amine of protein. Phencyclidine is unusual since the iminium product is non-conjugated. However, data indicate that the conformation present at the binding site can accommodate delocalization of the derived radical. For cocaine, various metabolites may play a role: iminium, nitroxyl radical, nitrosonium and formaldehyde. Dealkylation of the ether moiety of ecstasy provides a catechol function capable of redox cycling with the o-quinone partner. Amphetamine and methamphetamine also appear to function by way of the catechol route, as well as morphine and heroin. Tetrahydrocannabinol produces an epoxide, a

  9. Development of Novel Electrode Materials for the Electrocatalysis of Oxygen-Transfer and Hydrogen-Transfer Reactions

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, Brett Kimball [Iowa State Univ., Ames, IA (United States)

    2002-01-01

    Throughout this thesis, the fundamental aspects involved in the electrocatalysis of anodic O-transfer reactions and cathodic H-transfer reactions have been studied. The investigation into anodic O-transfer reactions at undoped and Fe(III)[doped MnO2 films] revealed that MnO2 film electrodes prepared by a cycling voltammetry deposition show improved response for DMSO oxidation at the film electrodes vs. the Au substrate. Doping of the MnO2 films with Fe(III) further enhanced electrode activity. Reasons for this increase are believed to involve the adsorption of DMSO by the Fe(III) sites. The investigation into anodic O-transfer reactions at undoped and Fe(III)-doped RuO2 films showed that the Fe(III)-doped RuO2-film electrodes are applicable for anodic detection of sulfur compounds. The Fe(III) sites in the Fe-RuO2 films are speculated to act as adsorption sites for the sulfur species while the Ru(IV) sites function for anodic discharge of H2O to generate the adsorbed OH species. The investigation into cathodic H-transfer reactions, specifically nitrate reduction, at various pure metals and their alloys demonstrated that the incorporation of metals into alloy materials can create a material that exhibits bifunctional properties for the various steps involved in the overall nitrate reduction reaction. The Sb10Sn20Ti70, Cu63Ni37 and Cu25Ni75 alloy electrodes exhibited improved activity for nitrate reduction as compared to their pure component metals. The Cu63Ni37 alloy displayed the highest activity for nitrate reduction. The final investigation was a detailed study of the electrocatalytic activity of cathodic H-transfer reactions (nitrate reduction) at various compositions of Cu-Ni alloy electrodes. Voltammetric response for NO3- at the Cu-Ni alloy electrode is superior to

  10. Placental Growth Factor Administration Abolishes Placental Ischemia-Induced Hypertension.

    Science.gov (United States)

    Spradley, Frank T; Tan, Adelene Y; Joo, Woo S; Daniels, Garrett; Kussie, Paul; Karumanchi, S Ananth; Granger, Joey P

    2016-04-01

    Preeclampsia is a pregnancy-specific disorder of new-onset hypertension. Unfortunately, the most effective treatment is early delivery of the fetus and placenta. Placental ischemia appears central to the pathogenesis of preeclampsia because placental ischemia/hypoxia induced in animals by reduced uterine perfusion pressure (RUPP) or in humans stimulates release of hypertensive placental factors into the maternal circulation. The anti-angiogenic factor soluble fms-like tyrosine kinase-1 (sFlt-1), which antagonizes and reduces bioavailable vascular endothelial growth factor and placental growth factor (PlGF), is elevated in RUPP rats and preeclampsia. Although PlGF and vascular endothelial growth factor are both natural ligands for sFlt-1, vascular endothelial growth factor also has high affinity to VEGFR2 (Flk-1) causing side effects like edema. PlGF is specific for sFlt-1. We tested the hypothesis that PlGF treatment reduces placental ischemia-induced hypertension by antagonizing sFlt-1 without adverse consequences to the mother or fetus. On gestational day 14, rats were randomized to 4 groups: normal pregnant or RUPP±infusion of recombinant human PlGF (180 μg/kg per day; AG31, a purified, recombinant human form of PlGF) for 5 days via intraperitoneal osmotic minipumps. On day 19, mean arterial blood pressure and plasma sFlt-1 were higher and glomerular filtration rate lower in RUPP than normal pregnant rats. Infusion of recombinant human PlGF abolished these changes seen with RUPP along with reducing oxidative stress. These data indicate that the increased sFlt-1 and reduced PlGF resulting from placental ischemia contribute to maternal hypertension. Our novel finding that recombinant human PlGF abolishes placental ischemia-induced hypertension, without major adverse consequences, suggests a strong therapeutic potential for this growth factor in preeclampsia.

  11. Epithelial membrane protein 2 (EMP2) deficiency alters placental angiogenesis, mimicking features of human placental insufficiency.

    Science.gov (United States)

    Williams, Carmen J; Chu, Alison; Jefferson, Wendy N; Casero, David; Sudhakar, Deepthi; Khurana, Nevil; Hogue, Claire P; Aryasomayajula, Chinmayi; Patel, Priya; Sullivan, Peggy; Padilla-Banks, Elizabeth; Mohandessi, Shabnam; Janzen, Carla; Wadehra, Madhuri

    2017-03-14

    Epithelial membrane protein-2 (EMP2) is a tetraspan protein predicted to regulate placental development. Highly expressed in secretory endometrium and trophectoderm cells, previous studies suggest that it may regulate implantation by orchestrating the surface expression of integrins and other membrane proteins. In order to test the role of EMP2 in pregnancy, mice lacking EMP2 (Emp2(-/-) ) were generated. Emp2(-/-) females are fertile but have reduced litter sizes when carrying Emp2(-/-) but not Emp2(+/-) fetuses. Placentas of Emp2(-/-) fetuses exhibit dysregulation in pathways related to neoangiogenesis, coagulation, and oxidative stress, and have increased fibrin deposition and altered vasculature. Given that these findings often occur due to placental insufficiency resulting in an oxygen-poor environment, the expression of hypoxia-inducible factor-1 alpha (HIF-1α) was examined. Placentas from Emp2(-/-) fetuses had increased total HIF-1α expression in large part through an increase in uterine NK (uNK) cells, demonstrating a unique interplay between uNK cells and trophoblasts modulated through EMP2. To determine if these results translated to human pregnancy, placentas from normal, term deliveries or those complicated by placental insufficiency resulting in intrauterine growth restriction (IUGR) were stained for EMP2. EMP2 was significantly reduced in both villous and extravillous trophoblast populations in IUGR placentas. Experiments in vitro using human trophoblast cells lines indicate that EMP2 modulates angiogenesis by altering HIF-1α expression. Our results reveal a novel role for EMP2 in regulating trophoblast function and vascular development in mice and humans and suggest it may be a new biomarker for placental insufficiency.

  12. Direct generation of oxygen-stabilized radicals by H• transfer from transition metal hydrides.

    Science.gov (United States)

    Kuo, Jonathan L; Hartung, John; Han, Arthur; Norton, Jack R

    2015-01-28

    Transition-metal hydrides generate α-alkoxy radicals by H• transfer to enol ethers. We have measured the rate constant for transfer from CpCr(CO)3H to n-butyl vinyl ether and have examined the chemistry of radicals generated by such transfers. Radicals from appropriate substrates undergo 5-exo cyclization, with higher diastereoselectivity than the analogous all-carbon radicals. From such radicals it is straightforward to make substituted tetrahydrofurans.

  13. An international network (PlaNet) to evaluate a human placental testing platform for chemicals safety testing in pregnancy

    DEFF Research Database (Denmark)

    Brownbill, Paul; Chernyavsky, Igor; Bottalico, Barbara;

    2016-01-01

    in pregnancy and how ex vivo and in vitro human placental models might be advanced to reproducible human placental test systems (HPTSs), refining a weight of evidence to the guidance given around compound risk assessment during pregnancy. The placental pharmacokinetics of xenobiotic transfer, dysregulated...... placental function in pregnancy-related pathologies and influx/efflux transporter polymorphisms are a few caveats that could be addressed by HPTSs, not the specific focus of current mammalian reproductive toxicology systems. An international consortium, “PlaNet”, will bridge academia, industry...... and regulators to consider screen ability and standardisation issues surrounding these models, with proven reproducibility for introduction into industrial and clinical practice....

  14. Imaging and assessment of placental function.

    LENUS (Irish Health Repository)

    Moran, Mary

    2011-09-01

    The placenta is the vital support organ for the developing fetus. This article reviews current ultrasound (US) methods of assessing placental function. The ability of ultrasound to detect placental pathology is discussed. Doppler technology to investigate the fetal, placental, and maternal circulations in both high-risk and uncomplicated pregnancies is discussed and the current literature on the value of three-dimensional power Doppler studies to assess placental volume and vascularization is also evaluated. The article highlights the need for further research into three-dimensional ultrasound and alternative methods of placental evaluation if progress is to be made in optimizing placental function assessment.

  15. Placental mitochondrial content and function in intrauterine growth restriction and preeclampsia.

    Science.gov (United States)

    Mandò, C; De Palma, C; Stampalija, T; Anelli, G M; Figus, M; Novielli, C; Parisi, F; Clementi, E; Ferrazzi, E; Cetin, I

    2014-02-15

    Intrauterine growth restriction (IUGR) and pregnancy hypertensive disorders such as preeclampsia (PE) associated with IUGR share a common placental phenotype called "placental insufficiency", originating in early gestation when high availability of energy is required. Here, we assess mitochondrial content and the expression and activity of respiratory chain complexes (RCC) in placental cells of these pathologies. We measured mitochondrial (mt)DNA and nuclear respiratory factor 1 (NRF1) expression in placental tissue and cytotrophoblast cells, gene and protein expressions of RCC (real-time PCR and Western blotting) and their oxygen consumption, using the innovative technique of high-resolution respirometry. We analyzed eight IUGR, six PE, and eight uncomplicated human pregnancies delivered by elective cesarean section. We found lower mRNA levels of complex II, III, and IV in IUGR cytotrophoblast cells but no differences at the protein level, suggesting a posttranscriptional compensatory regulation. mtDNA was increased in IUGR placentas. Both mtDNA and NRF1 expression were instead significantly lower in their isolated cytotrophoblast cells. Finally, cytotrophoblast RCC activity was significantly increased in placentas of IUGR fetuses. No significant differences were found in PE placentas. This study provides genuine new data into the complex physiology of placental oxygenation in IUGR fetuses. The higher mitochondrial content in IUGR placental tissue is reversed in cytotrophoblast cells, which instead present higher mitochondrial functionality. This suggests different mitochondrial content and activity depending on the placental cell lineage. Increased placental oxygen consumption might represent a limiting step in fetal growth restriction, preventing adequate oxygen delivery to the fetus.

  16. Oxygen transfer characteristics of water and bubble mixture pipe flow through two sudden contractions and expansions

    Institute of Scientific and Technical Information of China (English)

    尹则高; 解绍华; 程东升; 龙翔宇

    2014-01-01

    The dissolved oxygen (DO) concentration is an important index of water quality. This paper studies the dissolved oxygen recovery of the water and bubble mixture pipe flow through two sudden contractions and expansions. A 3-D computational fluid dy- namics model is established to simulate the water and bubble mixture flow with a DO transport model. An experiment is conducted to validate the mathematical model. The mathematical model is used to evaluate the effect of geometric parameters on the head loss coefficient, the relative saturation coefficient and the oxygen absorption efficiency. It is found that the contraction ratio is a signi- ficant influencing factor, other than the relative length and the relative distance. Given the same relative length and relative distance, the head loss coefficient, the relative saturation coefficient and the oxygen absorption efficiency increase with the decrease of the contraction ratio, respectively. Given the same relative length and contraction ratio, the head loss coefficient increases with the in- crease of the relative distance firstly, and then decreases gradually, in contrast, the relative saturation coefficient and the oxygen ab- sorption efficiency decrease with the increase of the relative distance firstly, and then increase gradually, the relative saturation coefficient and the oxygen absorption efficiency are inversely proportional to the head loss coefficient, respectively.

  17. The effect of oxygen transfer mechanism on the cathode performance based on proton-conducting solid oxide fuel cells

    KAUST Repository

    Hou, Jie

    2015-01-01

    Two types of proton-blocking composites, La2NiO4+δ-LaNi0.6Fe0.4O3-δ (LNO-LNF) and Sm0.2Ce0.8O2-δ-LaNi0.6Fe0.4O3-δ (SDC-LNF), were evaluated as cathode materials for proton-conducting solid oxide fuel cells (H-SOFCs) based on the BaZr0.1Ce0.7Y0.2O3-δ (BZCY) electrolyte, in order to compare and investigate the influence of two different oxygen transfer mechanism on the performance of the cathode for H-SOFCs. The X-ray diffraction (XRD) results showed that the chemical compatibility of the components in both compounds was excellent up to 1000°C. Electrochemical studies revealed that LNO-LNF showed lower area specific polarization resistances in symmetrical cells and better electrochemical performance in single cell tests. The single cell with LNO-LNF cathode generated remarkable higher maximum power densities (MPDs) and lower interfacial polarization resistances (Rp) than that with SDC-LNF cathode. Correspondingly, the MPDs of the single cell with the LNO-LNF cathode were 490, 364, 266, 180 mW cm-2 and the Rp were 0.103, 0.279, 0.587, 1.367 Ω cm2 at 700, 650, 600 and 550°C, respectively. Moreover, after the single cell with LNO-LNF cathode optimized with an anode functional layer (AFL) between the anode and electrolyte, the power outputs reached 708 mW cm-2 at 700°C. These results demonstrate that the LNO-LNF composite cathode with the interstitial oxygen transfer mechanism is a more preferable alternative for H-SOFCs than SDC-LNF composite cathode with the oxygen vacancy transfer mechanism.

  18. Dynamics of Proton Transfer to Internal Water during the Photosynthetic Oxygen-Evolving Cycle.

    Science.gov (United States)

    Brahmachari, Udita; Barry, Bridgette A

    2016-11-10

    In photosynthesis, the light-driven oxidation of water is a sustainable process, which converts solar to chemical energy and produces protons and oxygen. To enable biomimetic strategies, the mechanism of photosynthetic oxygen evolution must be elucidated. Here, we provide information concerning a critical step in the oxygen-evolving, or S-state, cycle. During this S3-to-S0 transition, oxygen is produced, and substrate water binds to the manganese-calcium catalytic site. Our spectroscopic and H2(18)O labeling experiments show that this S3-to-S0 step is associated with the protonation of an internal water cluster in a hydrogen-bonding network, which contains calcium. When compared to the protonated water cluster, formed during a preceding step, the S1-to-S2 transition, the S3-to-S0 hydronium ion is likely to be coordinated by additional water molecules. This evidence shows that internal water and the hydrogen bonding network act as a transient proton acceptor at multiple points in the oxygen-evolving cycle.

  19. Determination of Local Experimental Heat-Transfer Coefficients on Combustion Side of an Ammonia-Oxygen Rocket

    Science.gov (United States)

    Liebert, Curt H.; Ehlers, Robert C.

    1961-01-01

    Local experimental heat-transfer coefficients were measured in the chamber and throat of a 2400-pound-thrust ammonia-oxygen rocket engine with a nominal chamber pressure of 600 pounds per square inch absolute. Three injector configurations were used. The rocket engine was run over a range of oxidant-fuel ratio and chamber pressure. The injector that achieved the best performance also produced the highest rates of heat flux at design conditions. The heat-transfer data from the best-performing injector agreed well with the simplified equation developed by Bartz at the throat region. A large spread of data was observed for the chamber. This spread was attributed generally to the variations of combustion processes. The spread was least evident, however, with the best-performing injector.

  20. Estimating of gas transfer velocity using triple isotopes of dissolved oxygen.

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.; Abe, O.; Honda, M.; Saino, T.

    The atmosphere-ocean exchange of climatically important gases is determined by the transfer velocity (k) and concentration gradient across the interface. Based on observations in the northwestern subarctic Pacific and Sagami Bay, we report here...

  1. Molecules consolidate the placental mammal tree

    NARCIS (Netherlands)

    Springer, M.S.; Stanhope, M.J.; Madsen, O.; Jong, W.W.W. de

    2004-01-01

    Deciphering relationships among the orders of placental mammals remains an important problem in evolutionary biology and has implications for understanding patterns of morphological character evolution, reconstructing the ancestral placental genome, and evaluating the role of plate tectonics and dis

  2. Molecules consolidate the placental mammal tree

    NARCIS (Netherlands)

    Springer, M.S.; Stanhope, M.J.; Madsen, O.; Jong, W.W.W. de

    2004-01-01

    Deciphering relationships among the orders of placental mammals remains an important problem in evolutionary biology and has implications for understanding patterns of morphological character evolution, reconstructing the ancestral placental genome, and evaluating the role of plate tectonics and

  3. Placental lactogen levels in diabetic pregnancy.

    Science.gov (United States)

    Ursell, W; Brudenell, M; Chard, T

    1973-04-14

    A prospective study has been carried out of placental lactogen levels in pregnancy complicated by diabetes mellitus. The levels were higher than those in normal pregnant subjects; the higher levels were related to increased placental and fetal weight but more closely to the former; and lower levels were found when there was clinical evidence of placental dysfunction. Those patients requiring the largest insulin increment for the control of their diabetes in the pregnancy have placental lactogen levels in the higher range.

  4. Intrapritoneal Hemorrhage after Placental Abruption

    Directory of Open Access Journals (Sweden)

    Nahid Sakhavar

    2012-06-01

    Full Text Available A placental abruption or abruptio placentae (where in the placental lining has separated from the uterus of the mother is one of the complications caused by trauma during pregnancy. It lets the blood flow to infiltrate in the uterine lining and to develop Couvelaire uterus (also known as uteroplacental apoplexy and uterine atony (a condition in which a woman's uterine muscles lose the ability to contract after childbirth; however, it rarely develops considerable hemoperitoneum which needs hysterectomy. In this report, a unique case of placental abruption caused by trauma in a 28-year-old Afghan woman is introduced in which severity and duration of trauma because of delay in reaching health equipped center led to developing massive hemoperitoneum (infiltration of great amount of blood into the abdominal cavity and its complications.

  5. Plasma placental lactogen in pregnancy.

    Science.gov (United States)

    Raghuramulu, N

    1978-01-01

    Plasma placental lactogen (HPL) and urinary oestrogen levels were investigated in pregnant women belonging to low and high socio-economic groups. Plasma HPL levels increased progressively with increasing gestation in women of both the socio-economic groups. The mean values in the two groups were not statistically different at any period of gestation. No correlation was observed between the birth weight of the infant and the maternal plasma placental lactogen levels at term. A positive correlation was observed between urinary oestrogen excretion and plasma HPL concentration.

  6. Seasonal transfer of oxygen isotopes from precipitation and soil to the tree ring: source water versus needle water enrichment.

    Science.gov (United States)

    Treydte, Kerstin; Boda, Sonja; Graf Pannatier, Elisabeth; Fonti, Patrick; Frank, David; Ullrich, Bastian; Saurer, Matthias; Siegwolf, Rolf; Battipaglia, Giovanna; Werner, Willy; Gessler, Arthur

    2014-05-01

    For accurate interpretation of oxygen isotopes in tree rings (δ(18) O), it is necessary to disentangle the mechanisms underlying the variations in the tree's internal water cycle and to understand the transfer of source versus leaf water δ(18) O to phloem sugars and stem wood. We studied the seasonal transfer of oxygen isotopes from precipitation and soil water through the xylem, needles and phloem to the tree rings of Larix decidua at two alpine sites in the Lötschental (Switzerland). Weekly resolved δ(18) O records of precipitation, soil water, xylem and needle water, phloem organic matter and tree rings were developed. Week-to-week variations in needle-water (18) O enrichment were strongly controlled by weather conditions during the growing season. These short-term variations were, however, not significantly fingerprinted in tree-ring δ(18) O. Instead, seasonal trends in tree-ring δ(18) O predominantly mirrored trends in the source water, including recent precipitation and soil water pools. Modelling results support these findings: seasonal tree-ring δ(18) O variations are captured best when the week-to-week variations of the leaf water signal are suppressed. Our results suggest that climate signals in tree-ring δ(18) O variations should be strongest at temperate sites with humid conditions and precipitation maxima during the growing season.

  7. CD4+ T cells are important mediators of oxidative stress that cause hypertension in response to placental ischemia.

    Science.gov (United States)

    Wallace, Kedra; Cornelius, Denise C; Scott, Jeremy; Heath, Judith; Moseley, Janae; Chatman, Krystal; LaMarca, Babbette

    2014-11-01

    Preeclampsia is associated with oxidative stress, which is suspected to play a role in hypertension, placental ischemia, and fetal demise associated with the disease. Various cellular sources of oxidative stress, such as neutrophils, monocytes, and CD4(+) T cells have been suggested as culprits in the pathophysiology of preeclampsia. The objective of this study was to examine a role of circulating and placental CD4(+) T cells in oxidative stress in response to placental ischemia during pregnancy. CD4(+) T cells and oxidative stress were measured in preeclamptic and normal pregnant women, placental ischemic and normal pregnant rats, and normal pregnant recipient rats of placental ischemic CD4(+) T cells. Women with preeclampsia had significantly increased circulating (P=0.02) and placental CD4(+) T cells (P=0.0001); lymphocyte secretion of myeloperoxidase (P=0.004); and placental reactive oxygen species (P=0.0004) when compared with normal pregnant women. CD4(+) T cells from placental ischemic rats cause many facets of preeclampsia when injected into normal pregnant recipient rats on gestational day 13. On gestational day 19, blood pressure increased in normal pregnant recipients of placental ischemic CD4(+) T cells (P=0.002) compared with that in normal pregnant rats. Similar to preeclamptic patients, CD4(+) T cells from placental ischemic rats secreted significantly more myeloperoxidase (P=0.003) and induced oxidative stress in cultured vascular cells (P=0.003) than normal pregnant rat CD4(+)Tcells. Apocynin, a nicotinamide adenine dinucleotide phosphate inhibitor, attenuated hypertension and all oxidative stress markers in placental ischemic and normal pregnant recipient rats of placental ischemic CD4(+)Tcells (P=0.05). These data demonstrate an important role for CD4(+) T cells in mediating another factor, oxidative stress, to cause hypertension during preeclampsia. © 2014 American Heart Association, Inc.

  8. Altered placental development in undernourished rats: role of maternal glucocorticoids

    Directory of Open Access Journals (Sweden)

    Chen Chun-Hung

    2011-08-01

    Full Text Available Abstract Maternal undernutrition (MUN during pregnancy may lead to fetal intrauterine growth restriction (IUGR, which itself predisposes to adult risk of obesity, hypertension, and diabetes. IUGR may stem from insufficient maternal nutrient supply or reduced placental nutrient transfer. In addition, a critical role for maternal stress-induced glucocorticoids (GCs has been suggested to contribute to both IUGR and the ensuing risk of adult metabolic syndrome. While GC-induced fetal organ defects have been examined, there have been few studies on placental responses to MUN-induced maternal stress. Therefore, we hypothesize that 50% MUN associates with increased maternal GC levels and decreased placental HSD11B. This in turn leads to decreased placental and fetal growth, hence the need to investigate nutrient transporters. We measured maternal serum levels of corticosterone, and the placental basal and labyrinth zone expression of glucocorticoid receptor (NR3C1, 11-hydroxysteroid dehydrogenase B 1 (HSD11B-1 predominantly activates cortisone to cortisol and 11-dehydrocorticosterone (11-DHC to corticosterone, although can sometimes drive the opposing (inactivating reaction, and HSD11B-2 (only inactivates and converts corticosterone to 11-DHC in rodents in control and MUN rats at embryonic day 20 (E20. Moreover, we evaluated the expression of nutrient transporters for glucose (SLC2A1, SLC2A3 and amino acids (SLC38A1, 2, and 4. Our results show that MUN dams displayed significantly increased plasma corticosterone levels compared to control dams. Further, a reduction in fetal and placental weights was observed in both the mid-horn and proximal-horn positions. Notably, the placental labyrinth zone, the site of feto-maternal exchange, showed decreased expression of HSD11B1-2 in both horns, and increased HSD11B-1 in proximal-horn placentas, but no change in NR3C1. The reduced placental GCs catabolic capacity was accompanied by downregulation of SLC2A3, SLC

  9. Intramolecular electron transfer in ascorbate oxidase is enhanced in the presence of oxygen

    DEFF Research Database (Denmark)

    Farver, O; Wherland, S; Pecht, I

    1994-01-01

    Intramolecular electron transfer from the type 1 copper center to the type 3 copper(II) pair is induced in the multi-copper enzyme, ascorbate oxidase, following pulse radiolytic reduction of the type 1 Cu(II) ion. In the presence of a slight excess of dioxygen over ascorbate oxidase, interaction...... between the trinuclear copper center and O2 is observed even with singly reduced ascorbate oxidase molecules. Under these conditions, the rate constant for intramolecular electron transfer from type 1 Cu(I) to type 3 Cu(II) increases 5-fold to 1100 +/- 300 s-1 (20 degrees C, pH 5.8) as compared...

  10. Oxygen-atom transfer chemistry and thermolytic properties of a di-tert-butylphosphate-ligated Mn4O4 cubane.

    Science.gov (United States)

    Van Allsburg, Kurt M; Anzenberg, Eitan; Drisdell, Walter S; Yano, Junko; Tilley, T Don

    2015-03-16

    [Mn4O4{O2P(OtBu)2}6] (1), an Mn4O4 cubane complex combining the structural inspiration of the photosystem II oxygen-evolving complex with thermolytic precursor ligands, was synthesized and fully characterized. Core oxygen atoms within complex 1 are transferred upon reaction with an oxygen-atom acceptor (PEt3), to give the butterfly complex [Mn4O2{O2P(OtBu)2}6(OPEt3)2]. The cubane structure is restored by reaction of the latter complex with the O-atom donor PhIO. Complex 1 was investigated as a precursor to inorganic Mn metaphosphate/pyrophosphate materials, which were studied by X-ray absorption spectroscopy to determine the fate of the Mn4O4 unit. Under the conditions employed, thermolyses of 1 result in reduction of the manganese to Mn(II) species. Finally, the related butterfly complex [Mn4O2{O2P(pin)}6(bpy)2] (pin = pinacolate) is described.

  11. Multiple electron transfer systems in oxygen reducing biocathodes revealed by different conditions of aeration/agitation.

    Science.gov (United States)

    Rimboud, Mickaël; Bergel, Alain; Erable, Benjamin

    2016-08-01

    Oxygen reducing biocathodes were formed at -0.2V/SCE (+0.04V/SHE) from compost leachate. Depending on whether aeration was implemented or not, two different redox systems responsible for the electrocatalysis of oxygen reduction were evidenced. System I was observed at low potential (-0.03V/SHE) on cyclic voltammetries (CVs). It appeared during the early formation of the biocathode (few hours) and resisted the hydrodynamic conditions induced by the aeration. System II was observed at higher potential on CV (+0.46V/SHE); it required a longer lag time (up to 10days) and quiescent conditions to produce an electrochemical signal. The hydrodynamic effects produced by the forced aeration led to its extinction. From their different behaviors and examples in the literature, system I was identified as being a membrane-bound cytochrome-related molecule, while system II was identified as a soluble redox mediator excreted by the biofilm. This study highlighted the importance of controlling the local hydrodynamics to design efficient oxygen reducing biocathodes able to operate at high potential.

  12. Oxygen transfer materials with catalytic properties for biomass gasification[Dissertation 17302

    Energy Technology Data Exchange (ETDEWEB)

    Pecho, J.

    2007-06-15

    By application of olivine as bed material in a biomass gasifier such as the FICFB type (Fast Internal Circulating Fluidized Bed) in Guessing, Austria, an improvement of the gasification process was observed. Reduction of tars was measured and oxygen increase in the process was calculated. However, it took a while before these properties became clear. Aim of the project was to elucidate the mechanism with which olivine influences the system and to find a new material with improved properties for the gasification process. There were some factors which had be taken into account, e.g., amount of free lattice oxygen, reaction enthalpy, selectivity, mechanical and chemical stability, costs, desulphurization and decarbonisation. Several studies have shown that natural olivine ((Fe{sub x}Mg{sub 1-x}){sub 2}SiO{sub 4}) lowers tar formation in fluidized bed gasification of biomass. According to most authors, the phenomenon is related to the presence of iron oxide (Fe{sub 2}O{sub 3}) which is, e.g., formed during the calcination of olivine in air. To elucidate the role of the iron oxide, synthetic olivine with a molar ratio of Fe:Mg equal to unity has been exposed to gases that contained either wet methane or wet toluene as the only carbon source in a thermobalance interfaced to on-line gas analysis. The results provide strong evidence that the conversion of the carbon species is dominated by the stoichiometric reaction of binary iron oxide with hydrocarbons in the beginning of the reaction while catalytic reactions such as steam reforming contribute little to the observed tar reduction. This reaction path straightforwardly explains the influence of the olivine's origin or the pre-treatment on its chemical reactivity as it was reported by the various authors. To improve the catalytic properties and oxygen capacity of bed materials, we put our focus on perovskite type oxides La{sub x}Sr{sub 1-x}Cr{sub y}Mn{sub 1-y}O{sub 3} and Ba{sub 0.3}Sr{sub 0.7}Fe{sub 0.9}Mn{sub 0.1}O

  13. Placental diversity in malagasy tenrecs

    DEFF Research Database (Denmark)

    Enders, A C; Blankenship, T N; Goodman, S M;

    2007-01-01

    Placentation in tenrecs of the subfamily Oryzorictinae, family Tenrecidae, has not been described previously. The structure of the placenta of this group and especially of the genus Microgale was investigated to determine its similarity or dissimilarity to previously described placentas of the te...

  14. PLACENTAL SIZE AND PERINATAL OUTCOMES

    Directory of Open Access Journals (Sweden)

    Nagamani

    2015-03-01

    Full Text Available BACKGROUND : The human placenta, a transient organ or pregnancy provides information about fetal well - being and pregnancy outcome . AIMS: To study the placental ultrasound characters in relation to perinatal outcomes . SETTINGS: Tertiary care hospital in southern India . METHODS AND MATERIAL S: The study sample comprised 500 consecutive women who presented to the Depart ment of Obstetrics and Gynecology at the King George Hospital who met the inclusion criteria. Ultrasonographic study was performed using a transabdominal 3.5 MHz volume transducer. Post natally the weight of the baby and of the placenta was recorded. Perina tal outcome was assessed by birth weight, APGAR score and the need for admission in neonatal intensive care unit. STATISTICAL ANALYSIS : Pearson’s correlation analysis and Chi square test was used. Statistical significance was considered at a p value <0.05 . RESULTS: The mean placental thickness was 3.10 cm; 76% (n:380 had normal thickness. Mean placental diameter was 21.306 cm, and its weight varied from 310 women 62% (n:310. Correlation of placental thickness (normal and abnormal, with birth weight, the difference was significant ( <0.001. CONCLUSION: Ultrasound forms a readily available, fairly safe, effective non - invasive method to identify and prevent fetal malnutrition in a cost - effective way.

  15. The effect of solvent polarity on the balance between charge transfer and non-charge transfer pathways in the sensitization of singlet oxygen by pipi triplet states.

    Science.gov (United States)

    Schmidt, Reinhard

    2006-05-11

    A large set of literature kinetic data on triplet (T(1)) sensitization of singlet oxygen by two series of biphenyl and naphthalene sensitizers in solvents of strongly different polarity has been analyzed. The rate constants and the efficiencies of singlet oxygen formation are quantitatively reproduced by a model that assumes the competition of a non-charge transfer (nCT) and a CT deactivation channel. nCT deactivation occurs from a fully established spin-statistical equilibrium of (1)(T(1)(3)Sigma) and (3)(T(1)(3)Sigma) encounter complexes by internal conversion (IC) to lower excited complexes that dissociate to yield O(2)((1)Sigma(g)(+)), O(2)((1)Delta(g)), and O(2)((3)Sigma(g)(-)). IC of (1,3)(T(1)(3)Sigma) encounter complexes is controlled by an energy gap law that is generally valid for the transfer of electronic energy to and from O(2). (1,3)(T(1)(3)Sigma) nCT complexes form in competition to IC (1)(T(1)(3)Sigma) and (3)(T(1)(3)Sigma) exciplexes if CT interactions between T(1) and O(2) are important. The rate constants of exciplex formation depend via a Marcus type parabolic model on the corresponding free energy change DeltaG(CT), which varies with sensitizer triplet energy, oxidation potential, and solvent polarity. O(2)((1)Sigma(g)(+)), O(2)((1)Delta(g)), and O(2)((3)Sigma(g)(-)) are formed in the product ratio (1/6):(1/12):(3/4) in the CT deactivation channel. The balance between nCT and CT deactivation is described by the relative contribution p(CT) of CT induced deactivation calculated for a sensitizer of known triplet energy from its quenching rate constant. It is shown how the change of p(CT) influences the quenching rate constant and the efficiency of singlet oxygen formation in both series of sensitizers. p(CT) is sensitive to differences of solvent polarity and varies for the biphenyls and the naphthalenes as sigmoidal with DeltaG(CT). This quantitative model represents a realistic and general mechanism for the quenching of pipi triplet states by O

  16. Oxygen transfer coefficient and the kinetic parameters of exo-polygalacturonase production by Aspergillus flavipes FP-500 in shake flasks and bioreactor.

    Science.gov (United States)

    Gómez Sánchez, C E; Martínez-Trujillo, A; Aguilar Osorio, G

    2012-12-01

    To evaluate and compare the sensitivity of Exo-PG production and kinetic parameters of Aspergillus flavipes FP-500 to oxygen transfer condition in shake flasks and bioreactor. Aspergillus flavipes FP-500 was grown on pectin as carbon source in shake flasks and bioreactor at different oxygen transfer conditions. The volumetric coefficient of oxygen transfer (kLa) was modified by changing both, the flask size/medium volume ratio and the agitation speed. Higher biomass concentration, Exo-PG activity, maximum specific growth rate and yield coefficient were obtained in bioreactor at higher kLa value. A strong correlation was found between biomass, Exo-PG activity and growth-associated product coefficient to kLa in bioreactor but does not in shake flasks. The mathematical model provided a good description of growth, pectin consumption and Exo-PG production in submerged batch cultures carried out in bioreactor. Biomass concentration, Exo-PG activity and their kinetics of Aspergillus flavipes FP-500 were strongly influenced by oxygen transfer condition and cultivation system. Significance and Impact of Study The production of enzymes by fungal fermentation is strictly aerobic and understanding the influence of oxygen transfer condition on the production kinetic is of vital importance in order to design, optimize and translate bioprocesses to industrial scale. © 2012 The Society for Applied Microbiology.

  17. Mechanism of Anesthetic Toxicity: Metabolism, Reactive Oxygen Species, Oxidative Stress, and Electron Transfer

    OpenAIRE

    2011-01-01

    There is much literature on the toxic effects of anesthetics. This paper deals with both the volatiles and locals. Adverse effects appear to be multifaceted, with the focus on radicals, oxidative stress (OS), and electron transfer (ET). ET functionalities involved are quinone, iminoquinone, conjugated iminium, and nitrone. The non-ET routes involving radicals and OS apparently pertain to haloalkanes and ethers. Beneficial effects of antioxidants, evidently countering OS, are reported. Knowled...

  18. Quality of placental RNA: Effects of explant size and culture duration.

    Science.gov (United States)

    Brew, O; Nikolopoulou, E; Hughes, A; Christian, M; Lee, Y; Oduwole, O; Sullivan, M H F; Woodman, A

    2016-10-01

    We evaluated the impact of placental micro (≤50 mg) and macro (∼200 mg) explants, oxygen concentration and culture method on placental RNA quality after long-term culture. Our findings show that micro explants cultured at 8% oxygen have the best RNA quality and tissue structure. Macro explants were less viable after long-term culture. Macro explants and explants undergoing syncytial degeneration produced poor quality RNA and should be avoided. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Placental exosomes in normal and complicated pregnancy.

    Science.gov (United States)

    Mitchell, Murray D; Peiris, Hassendrini N; Kobayashi, Miharu; Koh, Yong Q; Duncombe, Gregory; Illanes, Sebastian E; Rice, Gregory E; Salomon, Carlos

    2015-10-01

    While there is considerable contemporary interest in elucidating the role of placenta-derived extracellular vesicles in normal and complicated pregnancies and their utility as biomarkers and therapeutic interventions, progress in the field is hindered by a lack of standardized extracellular vesicle taxonomy and isolation protocols. The term "extracellular vesicle" is nonspecific and refers to all membrane-bound vesicles from nanometer to micrometer diameters and of different biogenic origins. To meaningfully ascribe biological function and/or diagnostic and therapeutic utility to extracellular vesicles, and in particular exosomes, greater specificity and vesicle characterization is required. The current literature relating to exosome biology must be interpreted in this context. Exosomes are a subtype of extracellular vesicle that are specifically defined by an endosomal biogenesis and particle size (40-120 nm) and density (1.13-1.19 g/mL(-1)). Exosomes are specifically package with signaling molecules (including protein, messenger RNA, microRNA, and noncoding RNA) and are released by exocytosis into biofluid compartments. Exosomes regulate the activity of both proximal and distal target cells, including translational activity, angiogenesis, proliferation, metabolism, and apoptosis. As such, exosomal signaling represents an integral pathway mediating intercellular communication. During pregnancy, the placenta releases exosomes into the maternal circulation from as early as 6 weeks of gestation. Release is regulated by factors that include both oxygen tension and glucose concentration and correlates with placental mass and perfusion. The concentration of placenta-derived exosomes in maternal plasma increases progressively during gestation. Exosomes isolated from maternal plasma are bioactive in vitro and are incorporated into target cells by endocytosis. While the functional significance of placental exosomes in pregnancy remains to be fully elucidated, available

  20. Proton coupled electron transfer and redox-active tyrosine Z in the photosynthetic oxygen-evolving complex.

    Science.gov (United States)

    Keough, James M; Jenson, David L; Zuniga, Ashley N; Barry, Bridgette A

    2011-07-27

    Proton coupled electron transfer (PCET) reactions play an essential role in many enzymatic processes. In PCET, redox-active tyrosines may be involved as intermediates when the oxidized phenolic side chain deprotonates. Photosystem II (PSII) is an excellent framework for studying PCET reactions, because it contains two redox-active tyrosines, YD and YZ, with different roles in catalysis. One of the redox-active tyrosines, YZ, is essential for oxygen evolution and is rapidly reduced by the manganese-catalytic site. In this report, we investigate the mechanism of YZ PCET in oxygen-evolving PSII. To isolate YZ(•) reactions, but retain the manganese-calcium cluster, low temperatures were used to block the oxidation of the metal cluster, high microwave powers were used to saturate the YD(•) EPR signal, and YZ(•) decay kinetics were measured with EPR spectroscopy. Analysis of the pH and solvent isotope dependence was performed. The rate of YZ(•) decay exhibited a significant solvent isotope effect, and the rate of recombination and the solvent isotope effect were pH independent from pH 5.0 to 7.5. These results are consistent with a rate-limiting, coupled proton electron transfer (CPET) reaction and are contrasted to results obtained for YD(•) decay kinetics at low pH. This effect may be mediated by an extensive hydrogen-bond network around YZ. These experiments imply that PCET reactions distinguish the two PSII redox-active tyrosines.

  1. Placental ABC transporters, cellular toxicity and stress in pregnancy.

    Science.gov (United States)

    Aye, Irving L M H; Keelan, Jeffrey A

    2013-04-25

    The human placenta, in addition to its roles as a nutrient transfer and endocrine organ, functions as a selective barrier to protect the fetus against the harmful effects of exogenous and endogenous toxins. Members of the ATP-binding cassette (ABC) family of transport proteins limit the entry of xenobiotics into the fetal circulation via vectorial efflux from the placenta to the maternal circulation. Several members of the ABC family, including proteins from the ABCA, ABCB, ABCC and ABCG subfamilies, have been shown to be functional in the placenta with clinically significant roles in xenobiotic efflux. However, recent findings suggest that these transporters also protect placental tissue by preventing the cellular accumulation of cytotoxic compounds such as lipids, sterols and their derivatives. Such protective functions are likely to be particularly important in pregnancies complicated by inflammatory or oxidative stress, where the generation of toxic metabolites is enhanced. For example, ABC transporters have been shown to protect against the harmful effects of hypoxia and oxidative stress through increased expression and efflux of oxysterols and glutathione conjugated xenobiotics. However, this protective capacity may be diminished in response to the same stressors. Several studies in primary human trophoblast cells and animal models have demonstrated decreased expression and activity of placental ABC transporters with inflammatory, oxidative or metabolic stress. Several clinical studies in pregnancies complicated by inflammatory conditions such as preeclampsia and gestational diabetes support these findings, although further studies are required to determine the clinical relevance of the relationships between placental ABC transporter expression and activity, and placental function in stressed pregnancies. Such studies are necessary to fully understand the consequences of pregnancy disorders on placental function and viability in order to optimise pregnancy

  2. Xanthohumol induces generation of reactive oxygen species and triggers apoptosis through inhibition of mitochondrial electron transfer chain complex I.

    Science.gov (United States)

    Zhang, Bo; Chu, Wei; Wei, Peng; Liu, Ying; Wei, Taotao

    2015-12-01

    Xanthohumol is a prenylflavonoid extracted from hops (Humulus lupulus). It possesses anti-cancer and anti-inflammatory activities in vitro and in vivo, and offers therapeutic benefits for treatment of metabolic syndromes. However, the precise mechanisms underlying its pharmacological effects remain to be elucidated, together with its cellular target. Here, we provide evidence that xanthohumol directly interacts with the mitochondrial electron transfer chain complex I (NADH dehydrogenase), inhibits the oxidative phosphorylation, triggers the production of reactive oxygen species, and induces apoptosis. In addition, we show that as a result of the inhibition of the mitochondrial oxidative phosphorylation, xanthohumol exposure causes a rapid decrease of mitochondrial transmembrane potential. Furthermore, we showed that xanthohumol up-regulates the glycolytic capacity in cells, and thus compensates cellular ATP generation. Dissection of the multiple steps of aerobic respiration by extracellular flux assays revealed that xanthohumol specifically inhibits the activity of mitochondrial complex I, but had little effect on that of complex II, III and IV. Inhibition of complex I by xanthohumol caused the overproduction of reactive oxygen species, which are responsible for the induction of apoptosis in cancer cells. We also found that isoxanthohumol, the structural isomer of xanthohumol, is inactive to cells, suggesting that the reactive 2-hydroxyl group of xanthohumol is crucial for its targeting to the mitochondrial complex I. Together, the remodeling of cell metabolism revealed here has therapeutic potential for the use of xanthohumol.

  3. Light-independent reactive oxygen species (ROS) formation through electron transfer from carboxylated single-walled carbon nanotubes in water.

    Science.gov (United States)

    Hsieh, Hsin-Se; Wu, Renren; Jafvert, Chad T

    2014-10-07

    Promising developments in application of carbon nanotubes (CNTs) have raised concern regarding potential biological and environmental effects upon their inevitable release to the environment. Although some CNTs have been reported to generate reactive oxygen species (ROS) under light, limited information exists on ROS generation by these materials in the dark. In this study, generation of ROS was examined, initiated by electron transfer from biological electron donors through carboxylated single-walled carbon nanotubes (C-SWCNT) to molecular oxygen in water in the dark. In the presence of C-SWCNT, the oxidation of NADH (β-nicotinamide adenine dinucleotide, reduced form) and DTTre (DL-dithiothreitol, reduced form) was confirmed by light absorbance shifts (340 nm to 260 nm during oxidation of NADH to NAD(+), and increased light absorbance at 280 nm during oxidation of DTTre). Production of superoxide anion (O2(•-)) was detected by its selective reaction with a tetrazolium salt (NBT(2+)), forming a formazan product that is visible at 530 nm. A modified acid-quenched N,N-diethyl-p-phenylenediamine (DPD) assay was used to measure the accumulation of H2O2 in C-SWCNT suspensions containing O2 and NADH. In the same suspensions (i.e., containing C-SWCNT, NADH, and O2), pBR322 DNA plasmid was cleaved, although •OH was not detected when using •OH scavenging molecular probes. These results indicate that the oxidation of electron donors by C-SWCNT can be a light-independent source of ROS in water, and that electron shuttling through CNTs to molecular oxygen may be a potential mechanism for DNA damage by this specific CNT and potentially other carbon-based nanomaterials.

  4. Experimental and CFD-PBM Study of Oxygen Mass Transfer Coefficient in Different Impeller Configurations and Operational Conditions of a Two-Phase Partitioning Bioreactor.

    Science.gov (United States)

    Moradkhani, Hamed; Izadkhah, Mir-Shahabeddin; Anarjan, Navideh

    2017-02-01

    In this work, gas dispersion in a two-phase partitioning bioreactor is analyzed by calculating volumetric oxygen mass transfer coefficient which is modeled using a commercial computational fluid dynamics (CFD), code FLUENT 6.2. Dispersed oxygen bubbles dynamics is based on standard "k-ε" Reynolds-averaged Navier-Stokes (RANS) model. This paper describes a three-dimensional CFD model coupled with population balance equations (PBE) in order to get more confirming results of experimental measurements. Values of k L a are obtained using dynamic gassing-out method. Using the CFD simulation, the volumetric mass transfer coefficient is calculated based on Higbie's penetration theory. Characteristics of mass transfer coefficient are investigated for five configurations of impeller and three different aeration flow rates. The pitched six blade type, due to the creation of downward flow direction, leads to higher dissolved oxygen (DO) concentrations, thereby, higher values of k L a compared with other impeller compositions. The magnitude of dissolved oxygen percentage in the aqueous phase has direct correlation with impeller speed and any increase of the aeration magnitude leads to faster saturation in shorter periods of time. Agitation speeds of 300 to 800 rpm are found to be the most effective rotational speeds for the mass transfer of oxygen in two-phase partitioning bioreactors (TPPB).

  5. The cumulative effect of assisted reproduction procedures on placental development and epigenetic perturbations in a mouse model.

    Science.gov (United States)

    de Waal, Eric; Vrooman, Lisa A; Fischer, Erin; Ord, Teri; Mainigi, Monica A; Coutifaris, Christos; Schultz, Richard M; Bartolomei, Marisa S

    2015-12-15

    Assisted reproductive technologies (ART) are associated with several complications including low birth weight, abnormal placentation and increased risk for rare imprinting disorders. Indeed, experimental studies demonstrate ART procedures independent of existing infertility induce epigenetic perturbations in the embryo and extraembryonic tissues. To test the hypothesis that these epigenetic perturbations persist and result in adverse outcomes at term, we assessed placental morphology and methylation profiles in E18.5 mouse concepti generated by in vitro fertilization (IVF) in two different genetic backgrounds. We also examined embryo transfer (ET) and superovulation procedures to ascertain if they contribute to developmental and epigenetic effects. Increased placental weight and reduced fetal-to-placental weight ratio were observed in all ART groups when compared with naturally conceived controls, demonstrating that non-surgical embryo transfer alone can impact placental development. Furthermore, superovulation further induced overgrowth of the placental junctional zone. Embryo transfer and superovulation defects were limited to these morphological changes, as we did not observe any differences in epigenetic profiles. IVF placentae, however, displayed hypomethylation of imprinting control regions of select imprinted genes and a global reduction in DNA methylation levels. Although we did not detect significant differences in DNA methylation in fetal brain or liver samples, rare IVF concepti displayed very low methylation and abnormal gene expression from the normally repressed allele. Our findings suggest that individual ART procedures cumulatively increase placental morphological abnormalities and epigenetic perturbations, potentially causing adverse neonatal and long-term health outcomes in offspring.

  6. Determination of Reactive Intermediates During Anodic Oxygen-transfer Reactions at Lead Dioxide

    Institute of Scientific and Technical Information of China (English)

    AI Shi-yun; ZHANG Wen; GAO Meng-nan; GU Fen-lin; WANG Qing-jiang; JIN Li-tong

    2004-01-01

    The anodic discharge of water to produce adsorbed hydroxyl free radicals(*OH) is considered to be a prerequisite to anodic O-transfer reactions at a PbO2 electrode. In this work, a method was studied by means of high-performance liquid chromatography(HPLC) combined with electrochemical detection(ED) so as to investigate the production of hydroxyl free radicals(*OH) in the process of the anodic discharge of H2O at a PbO2 electrode. The voltammetric data obtained at the PbO2 electrode for the oxidation of salicylic acid to salicylate hydroxylation products(DHBAs) and the detection of DHBAs by means of HPLC-ED confirm the proposed mechanism.

  7. Erasmus Darwin's enlightened views on placental function.

    Science.gov (United States)

    Pijnenborg, R; Vercruysse, L

    2007-01-01

    In his major work "Zoonomia", Erasmus Darwin (1731-1802) devoted one chapter to the placenta, in which the new knowledge of the recently discovered element oxygen was applied to the functioning of this organ. He considered the "cavities" or "lacunae" in the placenta as the main areas for oxygenation of the fetal blood, as he thought them to be structurally comparable to the lungs and the gills of fish. He obviously was aware of species differences in the uterine arterial blood supply to the placenta between humans and cows, assuming a higher contractility of the vasculature in the latter species. The new evidence for a primarily respiratory role overshadowed ideas of a possible nutritive function of the placenta. Since Hunter's definitive demonstration of separate maternal and fetal blood circulations, nutritive functions of the placenta needed to be explained by transmembrane transport processes, which were unknown at that time. Instead Erasmus Darwin erroneously considered the amniotic fluid as the main source of nutrients for the fetus. His understanding of placental respiration found expression in his long poem on the history of life on earth.

  8. Optoacoustic measurements of human placenta and umbilical blood oxygenation

    Science.gov (United States)

    Nanovskaya, T. N.; Petrov, I. Y.; Petrov, Y.; Patrikeeva, S. L.; Ahmed, M. S.; Hankins, G. D. V.; Prough, D. S.; Esenaliev, R. O.

    2016-03-01

    Adequate oxygenation is essential for normal embryogenesis and fetal growth. Perturbations in the intrauterine oxidative environment during pregnancy are associated with several pathophysiological disorders such as pregnancy loss, preeclampsia, and intrauterine growth restriction. We proposed to use optoacoustic technology for monitoring placental and fetal umbilical blood oxygenation. In this work, we studied optoacoustic monitoring of oxygenation in placenta and umbilical cord blood ex vivo using technique of placenta perfusion. We used a medical grade, nearinfrared, tunable, optoacoustic system developed and built for oxygenation monitoring in blood vessels and in tissues. First, we calibrated the system for cord blood oxygenation measurements by using a CO-Oximeter (gold standard). Then we performed validation in cord blood circulating through the catheters localized on the fetal side of an isolated placental lobule. Finally, the oxygenation measurements were performed in the perfused placental tissue. To increase or decrease blood oxygenation, we used infusion of a gas mixture of 95% O2 + 5% CO2 and 95% N2 + 5% CO2, respectively. In placental tissue, up to four cycles of changes in oxygenation were performed. The optoacoustically measured oxygenation in circulating cord blood and in placental lobule closely correlated with the actual oxygenation data measured by CO-Oximeter. We plan to further test the placental and cord blood oxygenation monitoring with optoacoustics in animal and clinical studies.

  9. Structural and magnetic features of oxygen inserted [Co-O/Pt]n multi-layer matrix for spin transfer torque memory applications.

    Science.gov (United States)

    Lee, Ja Bin; An, Gwang Guk; Yang, Seung Mo; Hong, Jin Pyo

    2013-11-01

    We describe the influence of inserted oxygen atoms on the structural and magnetic properties of a [Co/Pt]n multi-layer matrix. The correlation of magnetic properties with oxygen gas flow rate was studied as an alternative perpendicular medium in spin transfer torque magnetic random access memory applications. Experimental analysis suggests that the addition of a small amount of oxygen atoms into the [Co/Pt]n multi-layer matrix leads to a high coercivity and proper magnetization performance, together with high thermal stability. Finally, the nature of the improved perpendicular medium behaviors is also discussed.

  10. The study on the heat transfer characteristics of oxygen fuel combustion boiler

    Science.gov (United States)

    Wu, Haibo; Liu, Zhaohui; Liao, Haiyan

    2016-10-01

    According to 350MW and 600MW boilers, under oxygen fuel condition, through the reasonable control of the primary and secondary flow and the correct option and revision of mathematical model, the temperature distribution, heat flux distribution and absorption heat distribution, etc. was obtained which compared with those under air condition. Through calculation, it is obtained that the primary and secondary flow mixed well, good tangentially fired combustion in furnace was formed, the temperature under air condition obviously higher than the temperature under O26 condition. The adiabatic flame temperature of wet cycle was slightly higher than that of dry cycle. The maximum heat load appeared on the waterwall around the burner area. The heat load gradually decreased along the furnace height up and down in burner area. The heat absorption capacity of the furnace under O26 was lower than that under the air condition. The heat absorption capacity of the platen heating surface under O26 was equal to that under air condition. And the heat absorbing capacity of waterwall under O26 was about7%~12% less than that under air condition.

  11. Intestinal and placental zinc transport pathways.

    Science.gov (United States)

    Ford, Dianne

    2004-02-01

    Mammalian members of the cation diffusion facilitator (CDF) and zrt-, irt-like protein (ZIP) families of Zn transporters, initially identified in Saccharomyces cerevisiae and Arabidopsis thalania spp., have been cloned during the last 8 years and have been classified as families SLC30 and SLC39 respectively. The cloning of human Zn transporters ZnT-like transporter 1 (hZTL1)/ZnT5 (SLC30A5) and hZIP4 (SLC39A4) were major advances in the understanding of the molecular mechanisms of dietary Zn absorption. Both transporters are localised at the enterocyte apical membrane and are, therefore, potentially of fundamental importance in dietary Zn uptake. hZTL1 mediates Zn uptake when expressed in Xenopus laevis oocytes and hZIP4 is mutated in most cases of the inherited Zn deficiency disease acrodermatitis enteropathica. Localisation of hZTL1/ZnT5 at the apical membrane of the placental syncytiotrophoblast indicates a fundamental role in the transfer of Slc30 Zn to the foetus. Observations in rodent models indicate that in the intestine increased Zn availability increases expression of Zn transporters. Human intestinal Caco-2 cells show a similar response to increasing the Zn2+ concentration of the nutrient medium in relation to the expression of mRNA corresponding to several Zn transporters and that of ZnT1 (SLC30A1) and hZTL1/ZnT5 proteins. In the human placental cell line JAR, however, expression at the mRNA level of a number of Zn transporters is not modified by Zn availability, whilst ZnT1 and hZTL1/ZnT5 proteins are reduced under Zn-supplemented conditions. These differences between Caco-2 and JAR cells in Zn transporter gene responses to Zn supply may reflect the different extracellular Zn concentrations encountered by the corresponding cell types in vitro.

  12. Placental chimerism in early human pregnancy

    Directory of Open Access Journals (Sweden)

    Ashutosh Halder

    2005-01-01

    Full Text Available Background0 : Human chimerism is rare and usually uncovered through investigations of ambiguous genitalia or blood grouping or prenatal diagnosis. Most of the publications on placental chimerism are mainly case reports. There is no systematic search with sensitive techniques for placental chimerism in human. Aim0 : This study was aimed to asses placental chimerism through two sensitive molecular techniques i.e., interphase fluorescent in situ hybridization and quantitative fluorescent PCR. Material and methods0 : Placental chimerism was analyzed using X & Y dual color fluorescent in-situ hybridization onto 154 placentae from natural conceptions, obtained at termination of pregnancy between 7 to 16 weeks of gestation. Results0 : Three cases of placental sex chromosome chimerism were observed (1.95%. Exclusion of maternal contamination and diagnosis was confirmed later by quantitative fluorescent PCR. Conclusion0 : This finding indicates that placental chimerism in early human pregnancy is not rare.

  13. Organization of the electron transfer chain to oxygen in the obligate human pathogen Neisseria gonorrhoeae: roles for cytochromes c4 and c5, but not cytochrome c2, in oxygen reduction.

    Science.gov (United States)

    Li, Ying; Hopper, Amanda; Overton, Tim; Squire, Derrick J P; Cole, Jeffrey; Tovell, Nicholas

    2010-05-01

    Although Neisseria gonorrhoeae is a prolific source of eight c-type cytochromes, little is known about how its electron transfer pathways to oxygen are organized. In this study, the roles in the respiratory chain to oxygen of cytochromes c(2), c(4), and c(5), encoded by the genes cccA, cycA, and cycB, respectively, have been investigated. Single mutations in genes for either cytochrome c(4) or c(5) resulted in an increased sensitivity to growth inhibition by excess oxygen and small decreases in the respiratory capacity of the parent, which were complemented by the chromosomal integration of an ectopic, isopropyl-beta-d-thiogalactopyranoside (IPTG)-inducible copy of the cycA or cycB gene. In contrast, a cccA mutant reduced oxygen slightly more rapidly than the parent, suggesting that cccA is expressed but cytochrome c(2) is not involved in electron transfer to cytochrome oxidase. The deletion of cccA increased the sensitivity of the cycB mutant to excess oxygen but decreased the sensitivity of the cycA mutant. Despite many attempts, a double mutant defective in both cytochromes c(4) and c(5) could not be isolated. However, a strain with the ectopically encoded, IPTG-inducible cycB gene with deletions in both cycA and cycB was constructed: the growth and survival of this strain were dependent upon the addition of IPTG, so gonococcal survival is dependent upon the synthesis of either cytochrome c(4) or c(5). These results define the gonococcal electron transfer chain to oxygen in which cytochromes c(4) and c(5), but not cytochrome c(2), provide alternative pathways for electron transfer from the cytochrome bc(1) complex to the terminal oxidase cytochrome cbb(3).

  14. Altered fetal growth, placental abnormalities, and stillbirth.

    Science.gov (United States)

    Bukowski, Radek; Hansen, Nellie I; Pinar, Halit; Willinger, Marian; Reddy, Uma M; Parker, Corette B; Silver, Robert M; Dudley, Donald J; Stoll, Barbara J; Saade, George R; Koch, Matthew A; Hogue, Carol; Varner, Michael W; Conway, Deborah L; Coustan, Donald; Goldenberg, Robert L

    2017-01-01

    Worldwide, stillbirth is one of the leading causes of death. Altered fetal growth and placental abnormalities are the strongest and most prevalent known risk factors for stillbirth. The aim of this study was to identify patterns of association between placental abnormalities, fetal growth, and stillbirth. Population-based case-control study of all stillbirths and a representative sample of live births in 59 hospitals in 5 geographic areas in the U.S. Fetal growth abnormalities were categorized as small (90th percentile) for gestational age at death (stillbirth) or delivery (live birth) using a published algorithm. Placental examination by perinatal pathologists was performed using a standardized protocol. Data were weighted to account for the sampling design. Among 319 singleton stillbirths and 1119 singleton live births at ≥24 weeks at death or delivery respectively, 25 placental findings were investigated. Fifteen findings were significantly associated with stillbirth. Ten of the 15 were also associated with fetal growth abnormalities (single umbilical artery; velamentous insertion; terminal villous immaturity; retroplacental hematoma; parenchymal infarction; intraparenchymal thrombus; avascular villi; placental edema; placental weight; ratio birth weight/placental weight) while 5 of the 15 associated with stillbirth were not associated with fetal growth abnormalities (acute chorioamnionitis of placental membranes; acute chorioamionitis of chorionic plate; chorionic plate vascular degenerative changes; perivillous, intervillous fibrin, fibrinoid deposition; fetal vascular thrombi in the chorionic plate). Five patterns were observed: placental findings associated with (1) stillbirth but not fetal growth abnormalities; (2) fetal growth abnormalities in stillbirths only; (3) fetal growth abnormalities in live births only; (4) fetal growth abnormalities in stillbirths and live births in a similar manner; (5) a different pattern of fetal growth abnormalities in

  15. Placental responses to changes in the maternal environment determine fetal growth

    Directory of Open Access Journals (Sweden)

    Kris Genelyn eDimasuay

    2016-01-01

    Full Text Available Placental responses to maternal perturbations are complex and remain poorly understood. Altered maternal environment during pregnancy such as hypoxia, stress, obesity, diabetes, toxins, altered nutrition, inflammation, and reduced utero-placental blood flow may influence fetal development, which can predispose to diseases later in life. The placenta being a metabolically active tissue responds to these perturbations by regulating the fetal supply of nutrients and oxygen and secretion of hormones into the maternal and fetal circulation. We have proposed that placental nutrient sensing integrates maternal and fetal nutritional cues with information from intrinsic nutrient sensing signaling pathways to balance fetal demand with the ability of the mother to support pregnancy by regulating maternal physiology, placental growth, and placental nutrient transport. Emerging evidence suggests that the nutrient-sensing signaling pathway mechanistic target of rapamycin (mTOR plays a central role in this process. Thus, placental nutrient sensing plays a critical role in modulating maternal-fetal resource allocation, thereby affecting fetal growth and the life-long health of the fetus.

  16. Placental origins of adverse pregnancy outcomes: potential molecular targets: an Executive Workshop Summary of the Eunice Kennedy Shriver National Institute of Child Health and Human Development.

    Science.gov (United States)

    Ilekis, John V; Tsilou, Ekaterini; Fisher, Susan; Abrahams, Vikki M; Soares, Michael J; Cross, James C; Zamudio, Stacy; Illsley, Nicholas P; Myatt, Leslie; Colvis, Christine; Costantine, Maged M; Haas, David M; Sadovsky, Yoel; Weiner, Carl; Rytting, Erik; Bidwell, Gene

    2016-07-01

    Although much progress is being made in understanding the molecular pathways in the placenta that are involved in the pathophysiology of pregnancy-related disorders, a significant gap exists in the utilization of this information for the development of new drug therapies to improve pregnancy outcome. On March 5-6, 2015, the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health sponsored a 2-day workshop titled Placental Origins of Adverse Pregnancy Outcomes: Potential Molecular Targets to begin to address this gap. Particular emphasis was given to the identification of important molecular pathways that could serve as drug targets and the advantages and disadvantages of targeting these particular pathways. This article is a summary of the proceedings of that workshop. A broad number of topics were covered that ranged from basic placental biology to clinical trials. This included research in the basic biology of placentation, such as trophoblast migration and spiral artery remodeling, and trophoblast sensing and response to infectious and noninfectious agents. Research findings in these areas will be critical for the formulation of the development of future treatments and the development of therapies for the prevention of a number of pregnancy disorders of placental origin that include preeclampsia, fetal growth restriction, and uterine inflammation. Research was also presented that summarized ongoing clinical efforts in the United States and in Europe that has tested novel interventions for preeclampsia and fetal growth restriction, including agents such as oral arginine supplementation, sildenafil, pravastatin, gene therapy with virally delivered vascular endothelial growth factor, and oxygen supplementation therapy. Strategies were also proposed to improve fetal growth by the enhancement of nutrient transport to the fetus by modulation of their placental transporters and the targeting of placental

  17. Animal Models of Human Placentation - A Review

    DEFF Research Database (Denmark)

    Carter, Anthony Michael

    2007-01-01

    This review examines the strengths and weaknesses of animal models of human placentation and pays particular attention to the mouse and non-human primates. Analogies can be drawn between mouse and human in placental cell types and genes controlling placental development. There are, however...... and endometrium is similar in macaques and baboons, as is the subsequent lacunar stage. The absence of interstitial trophoblast cells in the monkey is an important difference from human placentation. However, there is a strong resemblance in the way spiral arteries are invaded and transformed in the macaque...

  18. Replacement of an oxo by an imido group in oxotransferase model compounds: influence on the oxygen atom transfer.

    Science.gov (United States)

    Mösch-Zanetti, Nadia C; Wurm, Dietmar; Volpe, Manuel; Lyashenko, Ganna; Harum, Bastian; Belaj, Ferdinand; Baumgartner, Judith

    2010-10-04

    Treatment of [MoO(N-t-Bu)Cl(2)(dme)] (dme = dimethoxyethane) with 2 equiv of the potassium salts of Schiff base ligands of the type KArNC(CH(3))CHC(CH(3))O afforded oxo imido molybdenum(VI) compounds [MoO(N-t-Bu)L(2)] {1, with Ar = phenyl (L(Ph)), 2 with Ar = 2-tolyl (L(MePh)), 3 with Ar = 2,6-dimethylphenyl (L(Me2Ph)) and 4 with Ar = 2,6-diisopropylphenyl (L(iPr2Ph))}. We have also prepared related bisimido complexes [Mo(N-t-Bu)(2)L(2) (5 with L = L(Ph), 6 with L = L(MePh), and 7 with L = L(Me2Ph)) by treatment of [Mo(N-t-Bu)(2)Cl(2)(dme)] with 2 equiv of the potassium salt of the respective ligand. 1, 3, 5, and 6 were characterized via single crystal X-ray diffraction. The oxo imido complexes exhibit oxygen atom transfer (OAT) reactivity toward trimethyl phosphine. Kinetic data were obtained for 1 and 3 by UV/vis spectroscopy revealing decreased OAT reactivity in comparison to related dioxo complexes with the same Schiff base ligands and decreased reactivity of 1 versus 3. Cyclic voltammetry was used to probe the electronic situation at the molybdenum center showing reversible reduction waves for 3 and [MoO(2)(L(Me2Ph))(2)] at comparable potentials while 1 exhibits a significant lower potential. Density functional theory (DFT) calculations showed a higher electron density on oxygen in the oxo imido complexes.

  19. Maternal and fetal factors and placentation: implications for pre-eclampsia.

    Science.gov (United States)

    Huppertz, Berthold

    2014-07-01

    The etiology of preeclampsia is still mysterious and a source of a variety of hypotheses. Accordingly, there is a number of theories present today describing different pathways how this disorder may develop. The most cited hypothesis on the etiology of preeclampsia is based on an inadequate remodeling of uterine spiral arteries in the placental bed due to superficial trophoblast invasion followed by placental hypoxia. Since maternal blood into the placenta is only established after week 12 of gestation, an effect of a failure in arterial remodeling can only affect the placenta starting with the second trimester of pregnancy. Recent studies on early predictive biomarkers for preeclampsia (such as PP13, fetal hemoglobin and PIGF) have indicated that there are changes of the villous trophoblast already weeks before the onset of maternal blood flow into the placenta, i.e. during mid first trimester. Moreover, a number of studies has shown that in cases with impaired trophoblast invasion resulting in inadequate remodeling of uterine spiral arteries placental hypoxia does not occur. In all these studies where mostly indirect assessments of placental oxygen have been performed, a higher oxygen partial pressure within the placenta has been measured. This is in clear contrast to the old hypothesis where placental hypoxia is essential for the etiology of preeclampsia. New biomarkers from the maternal and/or fetal compartment for the early prediction of preeclampsia may help in identifying the real etiology of preeclampsia. We need to use this momentum to decipher the real causes of this syndrome.

  20. Proton transfer reactions associated with the reaction of the fully reduced, purified cytochrome C oxidase with molecular oxygen and ferricyanide.

    Science.gov (United States)

    Capitanio, Nazzareno; Capitanio, Giuseppe; De Nitto, Emanuele; Boffoli, Domenico; Papa, Sergio

    2003-04-29

    A study is presented on proton transfer associated with the reaction of the fully reduced, purified bovine heart cytochrome c oxidase with molecular oxygen or ferricyanide. The proton consumption associated with aerobic oxidation of the four metal centers changed significantly with pH going from approximately 3.0 H(+)/COX at pH 6.2-6.3 to approximately 1.2 H(+)/COX at pH 8.0-8.5. Rereduction of the metal centers was associated with further proton uptake which increased with pH from approximately 1.0 H(+)/COX at pH 6.2-6.3 to approximately 2.8 H(+)/COX at pH 8.0-8.5. Anaerobic oxidation of the four metal centers by ferricyanide resulted in the net release of 1.3-1.6 H(+)/COX in the pH range 6.2-8.2, which were taken up by the enzyme on rereduction of the metal centers. The proton transfer elicited by ferricyanide represents the net result of deprotonation/protonation reactions linked to anaerobic oxidoreduction of the metal centers. Correction for the ferricyanide-induced pH changes of the proton uptake observed in the oxidation and rereduction phase of the reaction of the reduced oxidase with oxygen gave a measure of the proton consumption in the reduction of O(2) to 2H(2)O. The results show that the expected stoichiometric proton consumption of 4H(+) in the reduction of O(2) to 2H(2)O is differently associated, depending on the actual pH, with the oxidation and reduction phase of COX. Two H(+)/COX are initially taken up in the reduction of O(2) to two OH(-) groups bound to the binuclear Fe a(3)-Cu(B) center. At acidic pHs the third and fourth protons are also taken up in the oxidative phase with formation of 2H(2)O. At alkaline pHs the third and fourth protons are taken up with formation of 2H(2)O only upon rereduction of COX.

  1. Co-adsorption of water and oxygen on GaN: Effects of charge transfer and formation of electron depletion layer

    Science.gov (United States)

    Wang, Qi; Puntambekar, Ajinkya; Chakrapani, Vidhya

    2017-09-01

    Species from ambient atmosphere such as water and oxygen are known to affect electronic and optical properties of GaN, but the underlying mechanism is not clearly known. In this work, we show through careful measurement of electrical resistivity and photoluminescence intensity under various adsorbates that the presence of oxygen or water vapor alone is not sufficient to induce electron transfer to these species. Rather, the presence of both water and oxygen is necessary to induce electron transfer from GaN that leads to the formation of an electron depletion region on the surface. Exposure to acidic gases decreases n-type conductivity due to increased electron transfer from GaN, while basic gases increase n-type conductivity and PL intensity due to reduced charge transfer from GaN. These changes in the electrical and optical properties, as explained using a new electrochemical framework based on the phenomenon of surface transfer doping, suggest that gases interact with the semiconductor surface through electrochemical reactions occurring in an adsorbed water layer present on the surface.

  2. Oxygen transfer as a tool for fine-tuning recombinant protein production by Pichia pastoris under glyceraldehyde-3-phosphate dehydrogenase promoter.

    Science.gov (United States)

    Güneş, Hande; Çalık, Pınar

    2016-07-01

    Effects of oxygen transfer on recombinant protein production by Pichia pastoris under glyceraldehyde-3-phosphate dehydrogenase promoter were investigated. Recombinant glucose isomerase was chosen as the model protein. Two groups of oxygen transfer strategies were applied, one of which was based on constant oxygen transfer rate where aeration rate was Q O/V = 3 and 10 vvm, and agitation rate was N = 900 min(-1); while the other one was based on constant dissolved oxygen concentrations, C DO = 5, 10, 15, 20 and 40 % in the fermentation broth, by using predetermined exponential glucose feeding with μ o = 0.15 h(-1). The highest cell concentration was obtained as 44 g L(-1) at t = 9 h of the glucose fed-batch phase at C DO = 20 % operation while the highest volumetric and specific enzyme activities were obtained as 4440 U L(-1) and 126 U g(-1) cell, respectively at C DO = 15 % operation. Investigation of specific enzyme activities revealed that keeping C DO at 15 % was more advantageous with an expense of relatively higher by-product formation and lower specific cell growth rate. For this strategy, the highest oxygen transfer coefficient and oxygen uptake rate were K L a = 0.045 s(-1) and OUR = 8.91 mmol m(-3) s(-1), respectively.

  3. Placental transport of large molecules –a study using human ex vivo placental perfusion

    DEFF Research Database (Denmark)

    Mathiesen, Line

    2011-01-01

    To maintain a healthy pregnancy, the exchange of substances between mother and fetus is vital. All transport of these substances takes place through the placenta, which is a temporary organ that serves its purpose from the implantation of the blastula to the birth of the term fetus, supplying...... nutrients, gas and waste transport between the maternal blood and the developing fetus and maintaining pregnancy by producing hormones. The placenta consists of cells of both maternal and fetal origin and forms a complex barrier between the maternal and fetal blood that allows for passage of different...... within two hours of perfusion with a fetal flow rate of 3 mL/min. Negative controls are added to ensure that substance transfer is not due to leakage, e.g. high molecular weight substances that only pass the placental barrier with bulk flow through a leakage in the fetal system. Dextran (40kD) can...

  4. Maternal Outcomes According to Placental Position in Placental Previa

    Directory of Open Access Journals (Sweden)

    Dong Gyu Jang, Ji Sun We, Jae Un Shin, Yun Jin Choi, Hyun Sun Ko, In Yang Park, Jong Chul Shin

    2011-01-01

    Full Text Available Purpose: The purpose of this retrospective cohort study was to elucidate whether the location of placenta below uterine incision in cesarean section is important in the development of maternal complications in placenta previa patients.Methods: The study was conducted on 409 patients 414 parturition at 3 hospitals in affiliation with the Catholic Medical Center, Seoul, Korea from May 1999 to December 2009. The subjects were divided to two groups: the group whose placenta was located in the anterior portion of the uterus (anterior group and the group whose placenta was located in the posterior portion of the uterus (posterior group. And then they are compared to each other. Logistic regression was used to control for confounding factors.Results: In the anterior group, regardless of confounding factors, the incidence of excessive blood loss (OR 2.97; 95% CI: 1.64-5.37, massive transfusion (OR 3.31; 95% CI: 1.33-8.26, placental accreta (OR 2.60, 95% CI: 1.40-4.83, and hysterectomy (OR 3.47, 95% CI: 1.39-8.68 was higher.Conclusion: Sonographic determination of the placental position where its location beneath the uterine incision is very important to predict maternal outcomes in placenta previa patients, and such cases, close attention should be paid for massive hemorrhage.

  5. Placental urocortins and CRF in late gestation.

    NARCIS (Netherlands)

    Pepels, P.P.L.M.; Spaanderman, M.E.A.; Bulten, J.; Smits, P.; Hermus, A.R.M.M.; Lotgering, F.K.; Sweep, C.G.J.

    2009-01-01

    Placental corticotropin-releasing factor (CRF) are thought to induce labor via activation of CRF receptor type 1 (CRF-R1) leading to several feed forward mechanisms in the placental, fetal and maternal compartments. Recently, receptor type 2 (CRF-R2) selective ligands called urocortin 2 and 3 (Ucn

  6. Placental iron uptake and its regulation

    NARCIS (Netherlands)

    M. Bierings (Marc)

    1989-01-01

    textabstractIron transport in pregnancy is an active one-way process, from mother to fetus. Early in gestation fetal iron needs are low, and so is trans-placental transport, but as erythropoiesis develops, rising fetal iron needs are met by trans-placental iron transport. Apparently, the fetus is pr

  7. Placental development during early pregnancy in sheep: Effects of embryo origin on vascularization

    Science.gov (United States)

    Grazul-Bilska, Anna T.; Johnson, Mary Lynn; Borowicz, Pawel P.; Bilski, Jerzy J.; Cymbaluk, Taylor; Norberg, Spencer; Redmer, Dale A.; Reynolds, Lawrence P.

    2014-01-01

    Utero-placental growth and vascular development are critical for pregnancy establishment that may be altered by various factors including assisted reproductive technologies (ART), nutrition, or others, leading to compromised pregnancy. We hypothesized that placental vascularization and expression of angiogenic factors are altered early in pregnancies after transfer of embryos created using selected ART methods. Pregnancies were achieved through natural mating (NAT), or transfer of embryos from natural mating (NAT-ET), or in vitro fertilization (IVF) or activation (IVA). Placental tissues were collected on day 22 of pregnancy. In maternal caruncles (CAR), vascular cell proliferation was less (P<0.05) for IVA than other groups. Compared to NAT, density of blood vessels was less (P<0.05) for IVF and IVA in fetal membranes (FM), and for NAT-ET, IVF and IVA in CAR. In FM, mRNA expression was decreased (P<0.01–0.08) in NAT-ET, IVF and IVA compared to NAT for vascular endothelial growth factor (VEGF) and its receptor FLT-1, placental growth factor (PGF), neuropilin (NP) 1 and 2, angiopoietin (ANGPT) 1 and 2, endothelial nitric oxide synthase (NOS3), hypoxia inducible factor-1A (HIF1A), fibroblast growth factor (FGF) 2 and its receptor FGFR2. In CAR, mRNA expression was decreased (P<0.01–0.05) in NAT-ET, IVF and IVA compared to NAT for VEGF, FLT-1, PGF, ANGPT1 and TEK. Decreased mRNA expression for 12 of 14 angiogenic factors across FM and CAR in NAT-ET, IVF and IVA pregnancies was associated with reduced placental vascular development, which would lead to poor placental function and compromised fetal and placental growth and development. PMID:24472816

  8. Structure-based modelling in reproductive toxicology: (Q)SARs for the placental barrier.

    Science.gov (United States)

    Hewitt, M; Madden, J C; Rowe, P H; Cronin, M T D

    2007-01-01

    The replacement of animal testing for endpoints such as reproductive toxicity is a long-term goal. This study describes the possibilities of using simple (quantitative) structure-activity relationships ((Q)SARs) to predict whether a molecule may cross the placental membrane. The concept is straightforward, if a molecule is not able to cross the placental barrier, then it will not be a reproductive toxicant. Such a model could be placed at the start of any integrated testing strategy. To develop these models the literature was reviewed to obtain data relating to the transfer of molecules across the placenta. A reasonable number of data were obtained and are suitable for the modelling of the ability of a molecule to cross the placenta. Clearance or transfer indices data were sought due to their ability to eliminate inter-placental variation by standardising drug clearance to the reference compound antipyrine. Modelling of the permeability data indicates that (Q)SARs with reasonable statistical fit can be developed for the ability of molecules to cross the placental barrier membrane. Analysis of the models indicates that molecular size, hydrophobicity and hydrogen-bonding ability are molecular properties that may govern the ability of a molecule to cross the placental barrier.

  9. A microphysiological model of the human placental barrier.

    Science.gov (United States)

    Blundell, Cassidy; Tess, Emily R; Schanzer, Ariana S R; Coutifaris, Christos; Su, Emily J; Parry, Samuel; Huh, Dongeun

    2016-08-02

    During human pregnancy, the fetal circulation is separated from maternal blood in the placenta by two cell layers - the fetal capillary endothelium and placental trophoblast. This placental barrier plays an essential role in fetal development and health by tightly regulating the exchange of endogenous and exogenous materials between the mother and the fetus. Here we present a microengineered device that provides a novel platform to mimic the structural and functional complexity of this specialized tissue in vitro. Our model is created in a multilayered microfluidic system that enables co-culture of human trophoblast cells and human fetal endothelial cells in a physiologically relevant spatial arrangement to replicate the characteristic architecture of the human placental barrier. We have engineered this co-culture model to induce progressive fusion of trophoblast cells and to form a syncytialized epithelium that resembles the syncytiotrophoblast in vivo. Our system also allows the cultured trophoblasts to form dense microvilli under dynamic flow conditions and to reconstitute expression and physiological localization of membrane transport proteins, such as glucose transporters (GLUTs), critical to the barrier function of the placenta. To provide a proof-of-principle for using this microdevice to recapitulate native function of the placental barrier, we demonstrated physiological transport of glucose across the microengineered maternal-fetal interface. Importantly, the rate of maternal-to-fetal glucose transfer in this system closely approximated that measured in ex vivo perfused human placentas. Our "placenta-on-a-chip" platform represents an important advance in the development of new technologies to model and study the physiological complexity of the human placenta for a wide variety of applications.

  10. Nomenclature and placental mammal phylogeny

    Directory of Open Access Journals (Sweden)

    Helgen Kristofer M

    2010-04-01

    Full Text Available Abstract An issue arising from recent progress in establishing the placental mammal Tree of Life concerns the nomenclature of high-level clades. Fortunately, there are now several well-supported clades among extant mammals that require unambiguous, stable names. Although the International Code of Zoological Nomenclature does not apply above the Linnean rank of family, and while consensus on the adoption of competing systems of nomenclature does not yet exist, there is a clear, historical basis upon which to arbitrate among competing names for high-level mammalian clades. Here, we recommend application of the principles of priority and stability, as laid down by G.G. Simpson in 1945, to discriminate among proposed names for high-level taxa. We apply these principles to specific cases among placental mammals with broad relevance for taxonomy, and close with particular emphasis on the Afrotherian family Tenrecidae. We conclude that no matter how reconstructions of the Tree of Life change in years to come, systematists should apply new names reluctantly, deferring to those already published and maximizing consistency with existing nomenclature.

  11. Textured Nanoporous Mo:BiVO4 Photoanodes with High Charge Transport and Charge Transfer Quantum Efficiencies for Oxygen Evolution

    Energy Technology Data Exchange (ETDEWEB)

    Nair, Vineet; Perkins, Craig L.; Lin, Qiyin; Law, Matt

    2016-04-01

    We have developed a simple spin coating method to make high-quality nanoporous photoelectrodes of monoclinic BiVO4 and studied the ability of these electrodes to transport photogenerated carriers to oxidize sulfite and water. Samples containing molybdenum and featuring [001] out-of-plane crystallographic texture show a photocurrent and external quantum efficiency (EQE) for sulfite oxidation as high as 3.1 mA cm-2 and 60%, respectively, at 1.23 V versus reversible hydrogen electrode. By using an optical model of the electrode stack to accurately determine the fraction of electrode absorptance due to the BiVO4 active layer, we estimate that on average 70 +/- 5% of all photogenerated carriers escape recombination. A comparison of internal quantum efficiency as a function of film processing, illumination direction, and film thickness shows that electron transport is efficient and hole transport limits the photocurrent (hole diffusion length <40 nm). We find that Mo addition primarily improves electron transport and texturing mostly improves hole transport. Mo enhances electron transport by thinning the surface depletion layer or passivating traps and recombination centers at grain boundaries and interfaces, while improved hole transport in textured films may result from more efficient lateral hole extraction due to the texturing itself or the reduced density of deep gap states observed in photoemission measurements. Photoemission data also reveal that the films have bismuth-rich, vanadium- and oxygen-deficient surface layers, while ion scattering spectroscopy indicates a Bi-V-O surface termination. Without added catalysts, the plain BiVO4 electrodes oxidized water with an initial photocurrent and peak EQE of 1.7 mA cm-2 and 30%, respectively, which equates to a hole transfer efficiency to water of >64% at 1.23 V. The electrodes quickly photocorrode during water oxidation but show good stability during sulfite oxidation and indefinite stability in the dark. By improving

  12. Teaching the fundamentals of electron transfer reactions in mitochondria and the production and detection of reactive oxygen species.

    Science.gov (United States)

    Mailloux, Ryan J

    2015-01-01

    Mitochondria fulfill a number of biological functions which inherently depend on ATP and O2(-•)/H2O2 production. Both ATP and O2(-•)/H2O2 are generated by electron transfer reactions. ATP is the product of oxidative phosphorylation whereas O2(-•) is generated by singlet electron reduction of di-oxygen (O2). O2(-•) is then rapidly dismutated by superoxide dismutase (SOD) producing H2O2. O2(-•)/H2O2 were once viewed as unfortunately by-products of aerobic respiration. This characterization is fitting considering over production of O2(-•)/H2O2 by mitochondria is associated with range of pathological conditions and aging. However, O2(-•)/H2O2 are only dangerous in large quantities. If produced in a controlled fashion and maintained at a low concentration, cells can benefit greatly from the redox properties of O2(-•)/H2O2. Indeed, low rates of O2(-•)/H2O2 production are required for intrinsic mitochondrial signaling (e.g. modulation of mitochondrial processes) and communication with the rest of the cell. O2(-•)/H2O2 levels are kept in check by anti-oxidant defense systems that sequester O2(-•)/H2O2 with extreme efficiency. Given the importance of O2(-•)/H2O2 in cellular function, it is imperative to consider how mitochondria produce O2(-•)/H2O2 and how O2(-•)/H2O2 genesis is regulated in conjunction with fluctuations in nutritional and redox states. Here, I discuss the fundamentals of electron transfer reactions in mitochondria and emerging knowledge on the 11 potential sources of mitochondrial O2(-•)/H2O2 in tandem with their significance in contributing to overall O2(-•)/H2O2 emission in health and disease. The potential for classifying these different sites in isopotential groups, which is essentially defined by the redox properties of electron donator involved in O2(-•)/H2O2 production, as originally suggested by Brand and colleagues is also surveyed in detail. In addition, redox signaling mechanisms that control O2(-•)/H2O2

  13. Teaching the fundamentals of electron transfer reactions in mitochondria and the production and detection of reactive oxygen species

    Directory of Open Access Journals (Sweden)

    Ryan J. Mailloux

    2015-04-01

    Full Text Available Mitochondria fulfill a number of biological functions which inherently depend on ATP and O2−•/H2O2 production. Both ATP and O2−•/H2O2 are generated by electron transfer reactions. ATP is the product of oxidative phosphorylation whereas O2−• is generated by singlet electron reduction of di-oxygen (O2. O2−• is then rapidly dismutated by superoxide dismutase (SOD producing H2O2. O2−•/H2O2 were once viewed as unfortunately by-products of aerobic respiration. This characterization is fitting considering over production of O2−•/H2O2 by mitochondria is associated with range of pathological conditions and aging. However, O2−•/H2O2 are only dangerous in large quantities. If produced in a controlled fashion and maintained at a low concentration, cells can benefit greatly from the redox properties of O2−•/H2O2. Indeed, low rates of O2−•/H2O2 production are required for intrinsic mitochondrial signaling (e.g. modulation of mitochondrial processes and communication with the rest of the cell. O2−•/H2O2 levels are kept in check by anti-oxidant defense systems that sequester O2−•/H2O2 with extreme efficiency. Given the importance of O2−•/H2O2 in cellular function, it is imperative to consider how mitochondria produce O2−•/H2O2 and how O2−•/H2O2 genesis is regulated in conjunction with fluctuations in nutritional and redox states. Here, I discuss the fundamentals of electron transfer reactions in mitochondria and emerging knowledge on the 11 potential sources of mitochondrial O2−•/H2O2 in tandem with their significance in contributing to overall O2−•/H2O2 emission in health and disease. The potential for classifying these different sites in isopotential groups, which is essentially defined by the redox properties of electron donator involved in O2−•/H2O2 production, as originally suggested by Brand and colleagues is also surveyed in detail. In addition, redox signaling mechanisms that control O2

  14. Prediction of low birth weight: the placental T2* estimated by MRI versus the uterine artery pulsatility index

    DEFF Research Database (Denmark)

    Sinding, Marianne Munk; Peters, David Alberg; Frøkjær, Jens Brøndum;

    CONTROL ID: 2516296 ABSTRACT FINAL ID: P22.05 TITLE: Prediction of low birth weight: the placental T2* estimated by MRI versus the uterine artery pulsatility index AUTHORS (FIRST NAME, LAST NAME): Marianne Sinding1, David Peters2, Jens B. Frøkjær3, 4, Ole B. Christiansen1, 4, Astrid Petersen5...... (MRI) variable T2* reflects the placental oxygenation and thereby placental function. Therefore, we aimed to evaluate the performance of placental T2* in the prediction of low birth weight using the uterine artery (UtA) pulsatility index (PI) as gold standard. Methods: The study population...... was a selected, mixed population regarding the risk of low birth weight. According to our national guidelines, pregnancies with ultrasound estimated fetal weight (EFW) birth weight. We included 96 pregnancies at 20-40 weeks' gestation, of which 68 had an EFW ≥ -15% and 28...

  15. Determining the effect of solid and liquid vectors on the gaseous interfacial area and oxygen transfer rates in two-phase partitioning bioreactors

    Energy Technology Data Exchange (ETDEWEB)

    Quijano, Guillermo [Departmento de Ingenieria Quimica y Tecnologia del Medio Ambiente, Universidad de Valladolid, Paseo del Prado de la Magdalena, s/n, 47005 Valladolid (Spain); Departamento de Biotecnologia y Bioingenieria, Centro de Investigacion y de Estudios, Avanzados del IPN (Cinvestav), Apdo. Postal 14-740, 07360 Mexico, D.F. (Mexico); Rocha-Rios, Jose [Departmento de Ingenieria Quimica y Tecnologia del Medio Ambiente, Universidad de Valladolid, Paseo del Prado de la Magdalena, s/n, 47005 Valladolid (Spain); Departamento de Ingenieria de Procesos e Hidraulica (IPH), Universidad Autonoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco No. 186, 09340 Mexico, D.F. (Mexico); Hernandez, Maria; Villaverde, Santiago [Departmento de Ingenieria Quimica y Tecnologia del Medio Ambiente, Universidad de Valladolid, Paseo del Prado de la Magdalena, s/n, 47005 Valladolid (Spain); Revah, Sergio [Departamento de Procesos y Tecnologia, Universidad Autonoma Metropolitana-Cuajimalpa, c/o IPH, UAM-Iztapalapa, Av. San Rafael Atlixco No. 186, 09340 Mexico, D.F. (Mexico); Munoz, Raul, E-mail: mutora@iq.uva.es [Departmento de Ingenieria Quimica y Tecnologia del Medio Ambiente, Universidad de Valladolid, Paseo del Prado de la Magdalena, s/n, 47005 Valladolid (Spain); Thalasso, Frederic [Departamento de Biotecnologia y Bioingenieria, Centro de Investigacion y de Estudios, Avanzados del IPN (Cinvestav), Apdo. Postal 14-740, 07360 Mexico, D.F. (Mexico)

    2010-03-15

    The effect of liquid and solid transfer vectors (silicone oil and Desmopan, respectively) on the gaseous interfacial area (a{sub g}) was evaluated in a two-phase partitioning bioreactor (TPPB) using fresh mineral salt medium and the cultivation broth of a toluene degradation culture (Pseudomonas putida DOT-T1E cultures continuously cultivated with and without silicone oil at low toluene loading rates). Higher values of a{sub g} were recorded in the presence of both silicone oil and Desmopan compared to the values obtained in the absence of a vector, regardless of the aqueous medium tested (1.6 and 3 times higher, respectively, using fresh mineral salt medium). These improvements in a{sub g} were well correlated to the oxygen mass transfer enhancements supported by the vectors (1.3 and 2.5 for liquid and solid vectors, respectively, using fresh medium). In this context, oxygen transfer rates of 2.5 g O{sub 2} L{sup -1} h{sup -1} and 1.3 g O{sub 2} L{sup -1} h{sup -1} were recorded in the presence of Desmopan and silicone oil, respectively, which are in agreement with previously reported values in literature. These results suggest that mass transfer enhancements in TPPBs might correspond to an increase in a{sub g} rather than to the establishment of a high-performance gas/vector/water transfer pathway.

  16. Induction of Heme Oxygenase-1 Attenuates Placental-Ischemia Induced Hypertension

    Science.gov (United States)

    George, Eric M.; Cockrell, Kathy; Aranay, Marietta; Csongradi, Eva; Stec, David E.; Granger, Joey P.

    2011-01-01

    Recent in vitro studies have reported that heme oxygenase-1 (HO-1) downregulates the angiostatic protein sFlt-1 from placental villous explants and that the HO-1 metabolites CO and bilirubin negatively regulates endothelin-1 and reactive oxygen species (ROS). Although sFlt-1, ET-1, and ROS have been implicated in the pathophysiology of hypertension during preeclampsia and in response to placental ischemia in pregnant rats, it is unknown whether chronic induction of HO-1 alters the hypertensive response to placental ischemia. The present study examined the hypothesis that HO-1 induction in a rat model of placental ischemia would beneficially affect blood pressure, angiogenic balance, superoxide, and ET-1 production in the ischemic placenta. To achieve this goal we examined the effects of cobalt protoporphyrin (CoPP), an HO-1 inducer, in the reduced uterine perfusion pressure (RUPP) placental ischemia model and in normal pregnant rats. In response to RUPP treatment, MAP increases 29mmHg (136 ± 7 vs. 106 ± 5 mmHg) which is significantly attenuated by CoPP (118 ± 5 mmHg). While RUPP treatment causes placental sFlt-1/VEGF ratios to alter significantly to an angiostatic balance (1 ± 0.1 vs 1.27 ± 0.2,), treatment with CoPP causes a significant shift in the ratio to an angiogenic balance (0.68 ± 0.1). Placental superoxide increased in RUPP (952.5 ± 278.8 vs 243.9 ± 70.5 RLU/min/mg), but was significantly attenuated by HO-1 induction (482.7 ± 117.4 RLU/min/mg). Also, preproendothelin message was significantly increased in RUPP, which was prevented by CoPP. These data indicate that HO-1, or its metabolites, are potential therapeutics for the treatment of preeclampsia. PMID:21383306

  17. Oxidative stress status and placental implications in diabetic rats undergoing swimming exercise after embryonic implantation.

    Science.gov (United States)

    Volpato, Gustavo Tadeu; Damasceno, Débora Cristina; Sinzato, Yuri Karen; Ribeiro, Viviane Maria; Rudge, Marilza Vieira Cunha; Calderon, Iracema Mattos Paranhos

    2015-05-01

    The potential benefits and risks of physical exercise on fetal development during pregnancy remain unclear. The aim was to analyze maternal oxidative stress status and the placental morphometry to relate to intrauterine growth restriction (IUGR) from diabetic female rats submitted to swimming program after embryonic implantation. Pregnant Wistar rats were distributed into 4 groups (11 animals/group): control-nondiabetic sedentary rats, control exercised-nondiabetic exercised rats, diabetic-diabetic sedentary rats, and diabetic exercised-diabetic exercised rats. A swimming program was used as an exercise model. At the end of pregnancy, the maternal oxidative stress status, placental morphology, and fetal weight were analyzed. The swimming program was not efficient to reduce the hyperglycemia-induced oxidative stress. This fact impaired placental development, resulting in altered blood flow and energy reserves, which contributed to a deficient exchange of nutrients and oxygen for the fetal development, leading to IUGR. © The Author(s) 2014.

  18. Increased Umbilical Cord PAI-1 Levels in Placental Insufficiency Are Associated with Fetal Hypoxia and Angiogenesis.

    Science.gov (United States)

    Seferovic, Maxim D; Gupta, Madhulika B

    2016-01-01

    In intrauterine growth restriction (IUGR), a subset of pregnancies undergoes placental vascular dysregulation resulting in restricted blood flow and fetal hypoxemia. Altered transcription of hypoxic regulated plasminogen activator inhibitor 1 (PAI-1) has been associated with pregnancy complications and angiogenic regulation. Here we assessed circulating PAI-1 as an indicator of placental insufficiency. Venous umbilical PAI-1 of hypoxemic (VpO2 20 versus 35 mmHg, p PAI-1 was increased (~10-fold, p PAI-1 levels correlated to blood oxygen (r = -0.68, p PAI-1 levels (r = 0.65, p PAI-1 inhibiting antibody (p PAI-1 as a potential marker of placental insufficiency and identify its close association with pathological hypoxia and angiogenesis in a subset of growth restricted pregnancies.

  19. Redox-inactive metal ions promoted the catalytic reactivity of non-heme manganese complexes towards oxygen atom transfer.

    Science.gov (United States)

    Choe, Cholho; Yang, Ling; Lv, Zhanao; Mo, Wanling; Chen, Zhuqi; Li, Guangxin; Yin, Guochuan

    2015-05-21

    Redox-inactive metal ions can modulate the reactivity of redox-active metal ions in a variety of biological and chemical oxidations. Many synthetic models have been developed to help address the elusive roles of these redox-inactive metal ions. Using a non-heme manganese(II) complex as the model, the influence of redox-inactive metal ions as a Lewis acid on its catalytic efficiency in oxygen atom transfer was investigated. In the absence of redox-inactive metal ions, the manganese(II) catalyst is very sluggish, for example, in cyclooctene epoxidation, providing only 9.9% conversion with 4.1% yield of epoxide. However, addition of 2 equiv. of Al(3+) to the manganese(II) catalyst sharply improves the epoxidation, providing up to 97.8% conversion with 91.4% yield of epoxide. EPR studies of the manganese(II) catalyst in the presence of an oxidant reveal a 16-line hyperfine structure centered at g = 2.0, clearly indicating the formation of a mixed valent di-μ-oxo-bridged diamond core, Mn(III)-(μ-O)2-Mn(IV). The presence of a Lewis acid like Al(3+) causes the dissociation of this diamond Mn(III)-(μ-O)2-Mn(IV) core to form monomeric manganese(iv) species which is responsible for improved epoxidation efficiency. This promotional effect has also been observed in other manganese complexes bearing various non-heme ligands. The findings presented here have provided a promising strategy to explore the catalytic reactivity of some di-μ-oxo-bridged complexes by adding non-redox metal ions to in situ dissociate those dimeric cores and may also provide clues to understand the mechanism of methane monooxygenase which has a similar diiron diamond core as the intermediate.

  20. A stochastic model for early placental development.

    KAUST Repository

    Cotter, Simon L

    2014-08-01

    In the human, placental structure is closely related to placental function and consequent pregnancy outcome. Studies have noted abnormal placental shape in small-for-gestational-age infants which extends to increased lifetime risk of cardiovascular disease. The origins and determinants of placental shape are incompletely understood and are difficult to study in vivo. In this paper, we model the early development of the human placenta, based on the hypothesis that this is driven by a chemoattractant effect emanating from proximal spiral arteries in the decidua. We derive and explore a two-dimensional stochastic model, and investigate the effects of loss of spiral arteries in regions near to the cord insertion on the shape of the placenta. This model demonstrates that disruption of spiral arteries can exert profound effects on placental shape, particularly if this is close to the cord insertion. Thus, placental shape reflects the underlying maternal vascular bed. Abnormal placental shape may reflect an abnormal uterine environment, predisposing to pregnancy complications. Through statistical analysis of model placentas, we are able to characterize the probability that a given placenta grew in a disrupted environment, and even able to distinguish between different disruptions.

  1. TRANSFER

    African Journals Online (AJOL)

    “Chemistry Department, Kenyatta University, P. 0. Box 43844 ... harvester (X) [L 2] in a manner consistent with the following Forster equation for long range energy transfer [3-7]. .... sensitive foods, chemical reactors and essences. Recently we ...

  2. Interhospital transfer of seriously sick ARDS patients using veno-venous Extracorporeal Membrane Oxygenation (ECMO): Concept of an ECMO transport team

    OpenAIRE

    Starck, C T; Hasenclever, P; Falk, V; Wilhelm, M.J.

    2013-01-01

    Background: Extracorporeal membrane oxygenation (ECMO) therapy constitutes the last option for patients with acute respiratory distress syndrome (ARDS) refractory to conservative treatment. Since primary care centers are unable to provide this therapy, such patients need a transfer to a tertiary care center, which may be life-threatening without extracorporeal support. Methods: An ECMO transport team implanted an ECMO at the site of the primary care center with subsequent transport of the pat...

  3. Power Consumption, Mixing Time, and Oxygen Mass Transfer in a Gas-Liquid Contactor Stirred with a Dual Impeller for Different Spacing

    Directory of Open Access Journals (Sweden)

    Hayder Mohammed Issa

    2016-01-01

    Full Text Available Multiple or dual impellers are widely implemented in stirred contactors used in various biological processes like fermentation, water treatment, and pharmaceutical production. The spacing between impellers is considered as a crucial factor in designing of these types of contactors resulting in variation of oxygen mass transfer, mixing time, or power consumption for such biological system. A study of three parts was conducted to characterize the effect of the spacing between impellers on the most important parameters that related to biological contactor performance: oxygen mass transfer coefficient kla from the gas phase (air to the liquid phase (water, mixing time, and power consumption for different operating rotational speeds (1.67–3.33 rps and for three different spacing positions. The used impellers system in the study is a dual impeller system which consists of an inverted and bladed rotated cone (IBRC and a pitched-blade up-flow propeller (PBPU. The experimental results showed that the shorter spacing (the lower PBPU in a higher position is more convenient, as the achieved oxygen mass transfer coefficient has showed an improvement in its values with lower mixing time and with a slight alteration in power consumption.

  4. Three-dimensional three-phase model for simulation of hydrodynamics, oxygen mass transfer, carbon oxidation, nitrification and denitrification in an oxidation ditch.

    Science.gov (United States)

    Lei, Li; Ni, Jinren

    2014-04-15

    A three-dimensional three-phase fluid model, supplemented by laboratory data, was developed to simulate the hydrodynamics, oxygen mass transfer, carbon oxidation, nitrification and denitrification processes in an oxidation ditch. The model provided detailed phase information on the liquid flow field, gas hold-up distribution and sludge sedimentation. The three-phase model described water-gas, water-sludge and gas-sludge interactions. Activated sludge was taken to be in a pseudo-solid phase, comprising an initially separated solid phase that was transported and later underwent biological reactions with the surrounding liquidmedia. Floc parameters were modified to improve the sludge viscosity, sludge density, oxygen mass transfer rate, and carbon substrate uptake due to adsorption onto the activated sludge. The validation test results were in very satisfactory agreement with laboratory data on the behavior of activated sludge in an oxidation ditch. By coupling species transport and biological process models, reasonable predictions are made of: (1) the biochemical kinetics of dissolved oxygen, chemical oxygen demand (COD) and nitrogen variation, and (2) the physical kinematics of sludge sedimentation.

  5. ULTRASONOGRAPHIC CORRELATION OF PLACENTAL THICKNESS WITH FETAL GESTATIONAL AGE AND GRADING OF PLACENTAL MATURIT

    Directory of Open Access Journals (Sweden)

    Nagesh

    2016-03-01

    Full Text Available AIMS AND OBJECTIVES Comparative correlation of placental thickness with foetal gestational age, and evaluation of placental maturity by ultrasonography. MATERIALS AND METHODS The study includes 100 normal singleton gestations between 10 to 40 weeks of gestation referred to our centre for routine antenatal ultrasound examination. All the women were evaluated by transabdominal ultrasonography. Foetal gestational age in weeks was determined by crown rump length, biparietal diameter, head circumference, abdominal circumference and femoral length. Placental thickness was measured in millimeters. All the placentae were graded using ultrasonographic grading system. RESULTS Our observations revealed that the placental thickness gradually increased from 11.8 mm at 12 weeks to 38.5 mm at 39 weeks. Placental thickness almost corresponds to advancing gestational age exhibiting a linear and direct growth. Progressive maturity changes were noted in placenta with advancing gestational age. CONCLUSION Placental thickness measured at cord insertion site can be used as one of the parameter for estimating foetal gestational age. Placental thickness measurement can also be used to differentiate certain abnormal conditions related to thick and thin placenta. Ultrasonographic placental grading helps to rule out certain conditions associated with premature or delayed placental maturation

  6. An international network (PlaNet) to evaluate a human placental testing platform for chemicals safety testing in pregnancy.

    Science.gov (United States)

    Brownbill, Paul; Chernyavsky, Igor; Bottalico, Barbara; Desoye, Gernot; Hansson, Stefan; Kenna, Gerry; Knudsen, Lisbeth E; Markert, Udo R; Powles-Glover, Nicola; Schneider, Henning; Leach, Lopa

    2016-09-01

    The human placenta is a critical life-support system that nourishes and protects a rapidly growing fetus; a unique organ, species specific in structure and function. We consider the pressing challenge of providing additional advice on the safety of prescription medicines and environmental exposures in pregnancy and how ex vivo and in vitro human placental models might be advanced to reproducible human placental test systems (HPTSs), refining a weight of evidence to the guidance given around compound risk assessment during pregnancy. The placental pharmacokinetics of xenobiotic transfer, dysregulated placental function in pregnancy-related pathologies and influx/efflux transporter polymorphisms are a few caveats that could be addressed by HPTSs, not the specific focus of current mammalian reproductive toxicology systems. An international consortium, "PlaNet", will bridge academia, industry and regulators to consider screen ability and standardisation issues surrounding these models, with proven reproducibility for introduction into industrial and clinical practice. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Hydrodynamics and oxygen mass transfer characteristics of petroleum based micro-emulsions in a packed bed split-cylinder airlift reactor

    Directory of Open Access Journals (Sweden)

    M. Keshavarz Moraveji

    2013-09-01

    Full Text Available The effects of aeration velocity and liquid properties on the pertinent hydrodynamic and mass transfer parameters in a split-cylinder airlift reactor (with and without packing were examined. Four different oil-in-water micro-emulsion systems containing kerosene, heavy naphtha, light naphtha and diesel as the oil at the concentration of 7% (v/v were used in the experiments and the results were compared with pure water. The experimental results showed that the gas (air hold-up and the volumetric gas-liquid oxygen transfer coefficient values for the micro-emulsion systems were usually greater than those of pure water. The packing installation increased the overall gas-liquid volumetric mass transfer coefficient by increasing the flow turbulence and Reynolds number, compared to the unpacked column. The packing increased the gas hold-up and decreased the bubble size and liquid circulation velocity. Furthermore, two empirical correlations were developed to predict the overall gas hold-up and volumetric oxygen transfer coefficient. A good agreement was observed between the experimental and correlated data.

  8. Hyperemesis gravidarum and placental dysfunction disorders

    NARCIS (Netherlands)

    Koudijs, Heleen M; Savitri, Ary I; Browne, Joyce L; Amelia, Dwirani; Baharuddin, Mohammad; Grobbee, Diederick E; Uiterwaal, Cuno S P M

    2016-01-01

    BACKGROUND: Evidence about the consequence of hyperemesis gravidarum (HG) on pregnancy outcomes is still inconclusive. In this study, we evaluated if occurrence of hyperemesis gravidarum is associated with placental dysfunction disorders and neonatal outcomes. METHODS: A prospective cohort study was

  9. Postpartum deaths: piglet, placental, and umbilical characteristics.

    Science.gov (United States)

    Rootwelt, V; Reksen, O; Farstad, W; Framstad, T

    2013-06-01

    The fetal growth of the piglet is highly dependent on its placenta, and the newborn piglet birth weight is highly associated with postpartum death. However, there is little information available in the literature on the assessment of the placenta in relation to postpartum death in piglets. The aim of this study was to evaluate the impact of the placental area and placental weight, status of the umbilical cord, and piglet birth characteristics, such as blood parameters, vitality score, and birth weight on postpartum death. All live born piglets in litters from 26 Landrace-Yorkshire sows were monitored during farrowing and the status of each was recorded, including placental area and placental weight and blood variables obtained from the piglets and umbilical veins. Out of the 386 live-born piglets, 16.8% died before weaning at 5 wk. Among these, 78.5% died within the first 3 d of life. Mean blood concentration of lactate was increased in piglets that did not survive to weaning (P = 0.003). Concentrations of hemoglobin and hematocrit were decreased (P Piglets born with a broken umbilical cord had a reduced vitality score vs. piglets born with an intact umbilical cord (P = 0.021), and they had an increased probability of dying before weaning (P = 0.050). Mean birth weight, body mass index, placental area (P piglets that died before weaning vs. those that survived. Birth weight and placental area were furthermore negatively associated with live litter size. Blood concentrations of IgG and albumin recorded at d 1 were decreased in piglets that died before weaning (P < 0.01), and blood concentration of albumin was positively associated with placental area (P < 0.001). We conclude that placental area and placental weight, status of the umbilical cord, birth weight, body mass index, blood concentrations of lactate, hemoglobin, and hematocrit recorded at birth, and blood concentrations of IgG and albumin recorded at d 1 were associated with postpartum death in this study

  10. Prediction of fetal acidemia in placental abruption

    OpenAIRE

    MATSUDA, Yoshio; OGAWA, Masaki; KONNO, Jun; MITANI, Minoru; MATSUI, Hideo

    2013-01-01

    Background To determine the major predictive factors for fetal acidemia in placental abruption. Methods A retrospective review of pregnancies with placental abruption was performed using a logistic regression model. Fetal acidemia was defined as a pH of less than 7.0 in umbilical artery. The severe abruption score, which was derived from a linear discriminant function, was calculated to determine the probability of fetal acidemia. Results Fetal acidemia was seen in 43 survivors (43/222, 19%)....

  11. Comparative aspects of trophoblast development and placentation

    Directory of Open Access Journals (Sweden)

    Enders Allen C

    2004-07-01

    Full Text Available Abstract Based on the number of tissues separating maternal from fetal blood, placentas are classified as epitheliochorial, endotheliochorial or hemochorial. We review the occurrence of these placental types in the various orders of eutherian mammals within the framework of the four superorders identified by the techniques of molecular phylogenetics. The superorder Afrotheria diversified in ancient Africa and its living representatives include elephants, sea cows, hyraxes, aardvark, elephant shrews and tenrecs. Xenarthra, comprising armadillos, anteaters and sloths, diversified in South America. All placentas examined from members of these two oldest superorders are either endotheliochorial or hemochorial. The superorder Euarchontoglires includes two sister groups, Glires and Euarchonta. The former comprises rodents and lagomorphs, which typically have hemochorial placentas. The most primitive members of Euarchonta, the tree shrews, have endotheliochorial placentation. Flying lemurs and all higher primates have hemochorial placentas. However, the lemurs and lorises are exceptional among primates in having epitheliochorial placentation. Laurasiatheria, the last superorder to arise, includes several orders with epitheliochorial placentation. These comprise whales, camels, pigs, ruminants, horses and pangolins. In contrast, nearly all carnivores have endotheliochorial placentation, whilst bats have endotheliochorial or hemochorial placentas. Also included in Laurasiatheria are a number of insectivores that have many conserved morphological characters; none of these has epitheliochorial placentation. Consideration of placental type in relation to the findings of molecular phylogenetics suggests that the likely path of evolution in Afrotheria was from endotheliochorial to hemochorial placentation. This is also a likely scenario for Xenarthra and the bats. We argue that a definitive epitheliochorial placenta is a secondary specialization and that it

  12. The roles of polycarboxylates in Cr(VI)/sulfite reaction system: Involvement of reactive oxygen species and intramolecular electron transfer

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Bo, E-mail: bjiang86upc@163.com [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, Shandong (China); School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033 (China); Wang, Xianli; Liu, Yukun [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, Shandong (China); Wang, Zhaohui [College of Environmental Science and Engineering, Donghua University, Shanghai 201620 (China); Southern Cross GeoScience, Southern Cross University, Lismore, NSW 2480 (Australia); Zheng, Jingtang, E-mail: jtzheng03@163.com [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, Shandong (China); Wu, Mingbo, E-mail: wumb@upc.edu.cn [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, Shandong (China)

    2016-03-05

    Highlights: • The formations of SO{sub 4}·{sup −} and OH·, involve in Cr(VI) reduction induced by S(IV). • Affinity of polycarboxylate to Cr(VI) accelerates Cr(VI) reduction rate. • Polycarboxylates can act as electron donors for Cr(VI) reduction retrenching S(IV). • Only oxalate can enhance the formations of SO{sub 4}·{sup −} and OH· in Cr(VI)/S(IV) system. - Abstract: In this study, the effects of polycarboxylates on both Cr(VI) reduction and S(IV) consumption in Cr(VI)/S(IV) system was investigated in acidic solution. Under aerobic condition, the productions of reactive oxygen species (ROS), i.e., SO{sub 4}·{sup −} and OH·, have been confirmed in S(IV) reducing Cr(VI) process by using electron spin resonance and fluorescence spectrum techniques, leading to the excess consumption of S(IV). However, when polycarboxylates (oxalic, citric, malic and tartaric acid) were present in Cr(VI)/S(IV) system, the affinity of polycarboxylates to CrSO{sub 6}{sup 2−} can greatly promote the reduction of Cr(VI) via expanding the coordination of Cr(VI) species from tetrahedron to hexahedron. Besides, as alternatives to S(IV), these polycarboxylates can also act as electron donors for Cr(VI) reduction via intramolecular electron transfer reaction, which is dependent on the energies of the highest occupied molecular orbital of these polycarboxylates. Notably, the variant electron donating capacity of these polycarboxylates resulted in different yield of ROS and therefore the oxidation efficiencies of other pollutants, e.g., rhodamine B and As(III). Generally, this study does not only shed light on the mechanism of S(IV) reducing Cr(VI) process mediated by polycarboxylates, but also provides an escalated, cost-effective and green strategy for the remediation of Cr(VI) using sulfite as a reductant.

  13. SEX STEROIDS MODULATE UTERINE-PLACENTAL VASCULATURE: IMPLICATIONS FOR OBSTETRICS AND NEONATAL OUTCOMES

    Directory of Open Access Journals (Sweden)

    Manuel eMaliqueo

    2016-04-01

    Full Text Available Adequate blood supply to the uterine-placental region is crucial to ensure the transport of oxygen and nutrients to the growing fetus. Multiple factors intervene to achieve appropriate uterine blood flow and the structuring of the placental vasculature during the early stages of pregnancy. Among these factors, oxygen concentrations, growth factors, cytokines and steroid hormones are the most important. Sex steroids are present in extremely high concentrations in the maternal circulation and are important paracrine and autocrine regulators of a wide range of maternal and placental functions. In this regard, progesterone and estrogens act as modulators of uterine vessels and decrease the resistance of the spiral uterine arteries. On the other hand, androgens have the opposite effect, increasing the vascular resistance of the uterus. Moreover, progesterone and estrogens modulate the synthesis and release of angiogenic factors by placental cells, which regulates trophoblastic invasion and uterine artery remodeling. In this scenario, it is not surprising that women with pregnancy-related pathologies, such as early miscarriages, preterm delivery, preeclampsia and fetal growth restriction, exhibit altered sex steroid concentrations.

  14. The distinct proteome of placental malaria parasites.

    Energy Technology Data Exchange (ETDEWEB)

    Fried, Michal; Hixson, Kim K.; Anderson, Lori; Ogata, Yuko; Mutabingwa, Theonest K.; Duffy, Patrick E.

    2007-09-01

    Malaria proteins expressed on the surface of Plasmodium falciparum infected erythrocytes (IE) mediate adhesion and are targeted by protective immune responses. During pregnancy, IE sequester in the placenta. Placental IE bind to the molecule chondroitin sulfate A (CSA) and preferentially transcribe the gene that encodes VAR2CSA, a member of the PfEMP1 variant surface antigen family. Over successive pregnancies women develop specific immunity to CSA-binding IE and antibodies to VAR2CSA. We used tandem mass spectrometry together with accurate mass and time tag technology to study IE membrane fractions of placental parasites. VAR2CSA peptides were detected in placental IE and in IE from children, but the MC variant of VAR2CSA was specifically associated with placental IE. We identified six conserved hypothetical proteins with putative TM or signal peptides that were exclusively expressed by the placental IE, and 11 such proteins that were significantly more abundant in placental IE. One of these hypothetical proteins, PFI1785w, is a 42kDa molecule detected by Western blot in parasites infecting pregnant women but not those infecting children.

  15. Oxidation of phenyl and hydride ligands of bis(pentamethylcyclopentadienyl)hafnium derivatives by nitrous oxide via selective oxygen atom transfer reactions: insights from quantum chemistry calculations.

    Science.gov (United States)

    Xie, Hujun; Liu, Chengcheng; Yuan, Ying; Zhou, Tao; Fan, Ting; Lei, Qunfang; Fang, Wenjun

    2016-01-21

    The mechanisms for the oxidation of phenyl and hydride ligands of bis(pentamethylcyclopentadienyl)hafnium derivatives (Cp* = η(5)-C5Me5) by nitrous oxide via selective oxygen atom transfer reactions have been systematically studied by means of density functional theory (DFT) calculations. On the basis of the calculations, we investigated the original mechanism proposed by Hillhouse and co-workers for the activation of N2O. The calculations showed that the complex with an initial O-coordination of N2O to the coordinatively unsaturated Hf center is not a local minimum. Then we proposed a new reaction mechanism to investigate how N2O is activated and why N2O selectively oxidize phenyl and hydride ligands of . Frontier molecular orbital theory analysis indicates that N2O is activated by nucleophilic attack by the phenyl or hydride ligand. Present calculations provide new insights into the activation of N2O involving the direct oxygen atom transfer from nitrous oxide to metal-ligand bonds instead of the generally observed oxygen abstraction reaction to generate metal-oxo species.

  16. EXERCISE EFFECT ON PLACENTAL COMPONENTS: SYSTEMATIC REVIEW AND META-ANALYSIS

    Directory of Open Access Journals (Sweden)

    Walter Krause Neto

    2015-12-01

    Full Text Available Physical exercise has been demonstrated a positive effect on many pregnancy outcomes. Placental components are important for exchanging oxygen and nutrients between mother and fetus. This study aimed to systematic review and meta-analysis whether physical exercise could induce a morphological adjustment on placenta components. We systematically searched PubMed database until October 30th, 2014. We included randomized and non-randomized studies with control group, which aimed to investigate the effect of the physical exercise (water, aerobic and resistance on placental components (placental weight and volume, villous volume and vascular volume, intervillous space and stem villi. Initially, we identified 222 articles, of which 9 articles were used for full text analysis. Finally, four articles were included in the systematic review and meta-analysis. Meta-analysis demonstrated that exercise appeared to affect placental weight (95% CI, 39.73g [4.66-74.80], placental volume (95% CI, 47.11 cm3 [37.99-56.23], intervillous space (95% CI, 16.76 cm3 [12.66-20.68], villous volume (95% CI, 46.01 cm3 [40.21-51.81], villous vascular volume (95% CI, 15.95 cm3 [7.83-24.07] and stem villi (95% CI, 6.00 cm3[4.25-7.75]. Apparently, physical exercise has a positive effect on placental components. However, this conclusion is based on a limited number of studies. Clearly, it stands the necessity of larger samples and better methodology quality.

  17. Human placental expression of SLIT/ROBO signaling cues: effects of preeclampsia and hypoxia.

    Science.gov (United States)

    Liao, Wu-Xiang; Laurent, Louise C; Agent, Sally; Hodges, Jennifer; Chen, Dong-Bao

    2012-04-01

    Preeclampsia is characterized by dysfunctional endothelium and impaired angiogenesis. Recent studies suggest that the neuronal guidance SLIT/ROBO system regulates tumor angiogenesis. This study investigated if SLIT and ROBO are differentially expressed in healthy term and preeclamptic placentas and if hypoxia regulates SLIT and ROBO expression in placental trophoblast and endothelial cells. Total RNA and protein were extracted from placental tissues of healthy term (n = 5) and preeclamptic (n = 6) pregnancies and used for SLIT/ROBO expression analyses with reverse transcription-polymerase chain reaction (RT-PCR), real-time quantitative-PCR, and immunoblotting. Paraffin-embedded tissues were processed to localize SLIT/ROBO proteins in placental villi by immunohistochemistry. BeWo choriocarcinoma cells and human umbilical vein endothelial cells (HUVEC) were treated with 2% or 10% oxygen or the hypoxia mimetic deferoxamine mesylate (100 μM) to test if hypoxia regulates SLIT/ROBO expression. SLIT2, SLIT3, ROBO1, and ROBO4 mRNA and proteins were detected in the placenta. SLIT2 and ROBO1 proteins localized in the syncytiotrophoblast, and SLIT3, ROBO1, and ROBO4 in capillary endothelium of the placental villi. Levels of ROBO1 and ROBO4 as well as sFLT1 (soluble fms-like tyrosine kinase-1) proteins were significantly greater in preeclamptic placentas compared to normal controls. Hypoxia significantly increased both mRNA and protein levels of SLIT2 in BeWo cells and of SLIT3, ROBO1, and ROBB4 in HUVEC. Thus, trophoblast and endothelial coexpression of SLIT/ROBO suggests an autocrine/paracrine regulatory system for regulating placental function. Differential expression of SLITs and ROBOs in healthy term and preeclamptic placentas and hypoxia regulation of their expressions in placental cells implicate a potential pathophysiological role for this system in preeclampsia.

  18. The placental RCAS1 expression during stillbirth

    Directory of Open Access Journals (Sweden)

    Tetlak Tomasz

    2005-06-01

    Full Text Available Abstract Background Independently of the fetal death cause the beginning and course of stillbirth is closely related with the growing cytotoxic activity at the maternal-fetal interface. RCAS1 participates in the inhibition of maternal immune response during pregnancy. The alterations of RCAS1 protein expression in placental cells seem to determine the beginning of the labor and participate in the placental abruption. The aim of the present study was to investigate RCAS1 expression in placentas obtained following stillbirths or normal term births. Methods: RCAS1 expression was evaluated by Western blot method with the use of monoclonal anti-RCAS1 antibody in 67 placental tissue samples. Pregnant women were divided into four groups according to the mode of labor onset – spontaneous or induced, and the type of labor, stillbirth or labor at term. Placental beta-Actin expression was chosen as a control protein. Relative amounts of placental RCAS1 were compared with the use of Student's t-test, whereas beta-Actin control data were compared with the use of Mann-Whitney U test. Results: The average relative amount of RCAS1 was significantly lower in women with induced stillbirths than in women with induced labor at term. Similarly, significantly lower RCAS1 placental levels were observed in patients with spontaneous stillbirths than in women with spontaneous labor at term. Significant differences in RCAS1 expression were also observed with the respect to the beginning of the stillbirth: spontaneous and induced. Lowest RCAS1 placental levels were observed in women with spontaneous stillbirth. Conclusions: These preliminary results indicate that the alterations of RCAS1 expression in the human placenta may be involved in the changes of maternal immune system that take place during stillbirth.

  19. Influence of methanol/sorbitol co-feeding rate on pAOX1 induction in a Pichia pastoris Mut+ strain in bioreactor with limited oxygen transfer rate.

    Science.gov (United States)

    Carly, F; Niu, H; Delvigne, F; Fickers, P

    2016-04-01

    High Pichia pastoris biomass density could be obtained using high co-feeding rate of methanol and sorbitol in a fed-batch or continuous culture, while further higher feeding rate finally leads to oxygen limitation in bioreactor. In the literature, there is lack of report about AOX1 promoter regulation with regard to dissolved oxygen level (DO). Therefore, in this work, chemostat cultures were performed to investigate the cell growth, metabolism and regulation of the AOX1 promoter (pAOX1) regarding co-feeding rate of optimized methanol/sorbitol mixture (methanol fraction 0.60 C-mol/C-mol) using a P. pastoris Mut+/pAOX1-lacZ strain. The oxygen transfer rates (OTR) in bioreactor were kept in the range of typical values of large bioreactor, i.e., 4-8 g/(L h) if DO equals 30 % saturation or 5-10 g/(L h) if DO nears zero. For DO >0, an increase of the carbon fed led to an increase of pAOX1 induction. By contrast, when dissolved oxygen was completely depleted, methanol accumulated, causing a 30 % decrease of pAOX1 induction. However, this decrease is more likely to be lined to methanol accumulation than to low level of dissolved oxygen (Methanol/sorbitol co-feeding allowed cells to adapt to oxygen transient limitations that often occur at industrial scale with reduced effect on pAOX1 induction. The optimal feeding rate tested here was 6.6 mmol C (DCW h)(-1) at an OTR of 8.28 g O2(L h)(-1) with over fivefold pAOX1 induction (probably directly associated with target protein productivity) compared with previous work.

  20. 用于污水处理的柔性纤维膜反应器氧传递及动力学研究%Oxygen Transfer and Hydrodynamics in a Flexible Fibre Biofilm Reactor for Wastewater Treatment

    Institute of Scientific and Technical Information of China (English)

    陈育如; 虞启明; 徐红卫; 陈雁

    2009-01-01

    A flexible fibre biofilm reactor was developed for treatment of organic wastewaters. The hydrodynamic characteristics and mass transfer coefficients of oxygen were studied and compared with those of the conventional activated sludge processes. Tracer experiments were performed to obtain the residence time distributions of the reactors. The results indicated that both reactors could be treated as mixed flow reactors. The effects of flow rates of water and air on the overall mass transfer coefficient of oxygen were investigated, and the correlations between the mass transfer coefficient and the ratio of flow rates were obtained. Compared to the conventional activated sludge reactor, the mass transfer coefficients in the flexible fibre reactor were similar to but slightly lower, and less sensitive to the variation in the ratio of flow rates. It indicated that the fibre packing in the reactor hindered the oxygen transfer to some extent.

  1. Endocrine activity of extraembryonic membranes extends beyond placental amniotes.

    Directory of Open Access Journals (Sweden)

    Lori C Albergotti

    Full Text Available BACKGROUND: During development, all amniotes (mammals, reptiles, and birds form extraembryonic membranes, which regulate gas and water exchange, remove metabolic wastes, provide shock absorption, and transfer maternally derived nutrients. In viviparous (live-bearing amniotes, both extraembryonic membranes and maternal uterine tissues contribute to the placenta, an endocrine organ that synthesizes, transports, and metabolizes hormones essential for development. Historically, endocrine properties of the placenta have been viewed as an innovation of placental amniotes. However, an endocrine role of extraembryonic membranes has not been investigated in oviparous (egg-laying amniotes despite similarities in their basic structure, function, and shared evolutionary ancestry. In this study, we ask whether the oviparous chorioallantoic membrane (CAM of chicken (Gallus gallus has the capability to synthesize and receive signaling of progesterone, a major placental steroid hormone. METHODOLOGY/PRINCIPAL FINDINGS: We quantified mRNA expression of key steroidogenic enzymes involved in progesterone synthesis and found that 3beta-hydroxysteroid dehydrogenase, which converts pregnenolone to progesterone exhibited a 464 fold increase in the CAM from day 8 to day 18 of embryonic development (F(5, 68 = 89.282, p<0.0001. To further investigate progesterone synthesis, we performed explant culture and found that the CAM synthesizes progesterone in vitro in the presence of a steroid precursor. Finally, we quantified mRNA expression and performed protein immunolocalization of the progesterone receptor in the CAM. CONCLUSIONS/SIGNIFICANCE: Collectively, our data indicate that the chick CAM is steroidogenic and has the capability to both synthesize progesterone and receive progesterone signaling. These findings represent a paradigm shift in evolutionary reproductive biology by suggesting that endocrine activity of extraembryonic membranes is not a novel characteristic of

  2. Orbital-selective charge transfer at oxygen-deficient LaAlO3/SrTiO3(001) interfaces

    Science.gov (United States)

    Ong, P. V.; Lee, Jaichan

    2013-05-01

    Density-functional theory within the local density approximation + Hubbard U approach was used to study interface electronic structures in stoichiometric and oxygen-deficient LaAlO3/SrTiO3 (LAO/STO) superlattices with regularly spaced n-type and p-type interfaces. Asymmetric behaviors between complementary n-type and p-type interfaces were revealed in terms of orbital-selective charge transfer. Extra electrons induced by oxygen vacancies at the p-type interface easily spread to the n-type interface and occupy the Ti 3dxyorbitals, while those induced by the vacancies at the n-type interface are strictly confined and reside in Ti 3dx2-y2 and/or 3d3z2-r2 orbtials. The electronic behavior of oxygen vacancies at the LAO/STO interfaces and the possibility of distinguishing between intrinsic electronic states, which are induced by the polar catastrophe, and extrinsic states due to oxygen vacancies are discussed in detail.

  3. [Mass-transfer, utilization, and diffusion of oxygen in skeletal muscles of the stenohaline goby Gobius cobitus Pallas under conditions of hypoosmotic medium].

    Science.gov (United States)

    Soldatov, A A

    2012-01-01

    Effect of hypoosmotic conditions of medium on oxygen regime of skeletal muscles of the stenohalin goby Gobius cobitus Pallas was studied under conditions of experiment. The control fish group was maintained at 12-14 %o, the experimental one - at 4.8-5.6 per thousand. Duration of the experiment - 44-45 days, water temperature - 15 +/- 1 degrees C, photoperiod - 12 day/12 night. It was established that under conditions of external hypoosmia there occurred hydration of the goby skeletal muscles and a decrease of their diffusion capability with respect to oxygen. The latter was accompanied by the tissue P(O2) decrease, which is indicated by low values of P(O2) in the venous blood outflowing from muscles. For the first 14-16 days of adaptation to the hypoosmotic medium there were restricted processes of mass transfer and oxygen utilization, which was associated with a decrease of the voluminous tissue blood flow and the blood oxygen concentration. These changes occurred on the background of the blood plasma hydration and a decrease of the number of circulated erythrocytes, and then they were completely compensated.

  4. Scale-up of naringinase production process based on the constant oxygen transfer rate for a novel strain of Bacillus methylotrophicus.

    Science.gov (United States)

    Raval, Keyur; Gehlot, Kartik; B D, Prasanna

    2017-02-07

    Naringinase bioprocess based on Bacillus methylotrophicus was successfully scaled up based on constant oxygen transfer rate (OTR) as the scale-up criterion from 5-L bioreactor to 20-L bioreactor. OTR was measured in 5 and 20-L bioreactor under various operating conditions using dynamic method. The operating conditions, where complete dispersion was observed were identified. The highest OTR of 0.035 and 0.04 mMol/L/s was observed in 5 and 20-L bioreactor, respectively. Critical dissolved oxygen concentration of novel isolated strain B. methylotrophicus was found to be 20% of oxygen saturation in optimized medium. The B. methylotrophicus cells grown on sucrose had maximum oxygen uptake rate of 0.14 mMol/L/s in optimized growth medium. The cells produced the maximum naringinase activity of 751 and 778 U/L at 34 hr in 5 and 20-L bioreactors, respectively. The maximum specific growth rate of about 0.178/hr was observed at both the scales of operations. The maximum naringinase yield of 160 and 164 U/g biomass was observed in 5 and 20-L bioreactors, respectively. The growth and production profiles at both scales were similar indicating successful scale-up strategy for B. methylotrophicus culture.

  5. Generation of Triplet Excited States via Photoinduced Electron Transfer in meso-anthra-BODIPY: Fluorogenic Response toward Singlet Oxygen in Solution and in Vitro

    KAUST Repository

    Filatov, Mikhail A.

    2017-04-14

    Heavy atom-free BODIPY-anthracene dyads (BADs) generate locally excited triplet states by way of photoinduced electron transfer (PeT), followed by recombination of the resulting charge-separated states (CSS). Subsequent quenching of the triplet states by molecular oxygen produces singlet oxygen (1O2), which reacts with the anthracene moiety yielding highly fluorescent species. The steric demand of the alkyl substituents in the BODIPY subunit defines the site of 1O2 addition. Novel bis- and tetraepoxides and bicyclic acetal products, arising from rearrangements of anthracene endoperoxides were isolated and characterized. 1O2 generation by BADs in living cells enables visualization of the dyads distribution, promising new imaging applications.

  6. Discovery of Carbon/Oxygen depleted Blue Straggler Stars in 47 Tucanae: the chemical signature of a mass-transfer formation process

    CERN Document Server

    Ferraro, F R; Gratton, R; Piotto, G; Lanzoni, B; Carretta, E; Rood, R T; Sills, A; Pecci, F F; Möhler, S; Beccari, G; Lucatello, S; Compagni, N

    2006-01-01

    We use high-resolution spectra obtained with the ESO Very Large Telescope to measure surface abundance patterns of 43 Blue Stragglers stars (BSS) in 47 Tuc. We discovered that a sub-population of BSS shows a significant depletion of Carbon and Oxygen with respect to the dominant population. This evidence would suggest the presence of CNO burning products on the BSS surface coming from a deeply peeled parent star, as expected in the case of mass-transfer process. This is the first detection of a chemical signature clearly pointing to a specific BSS formation process in a globular cluster.

  7. Oxygen transfer from an intramolecularly coordinated diaryltellurium oxide to acetonitrile. Formation and combined AIM and ELI-D analysis of a novel diaryltellurium acetimidate.

    Science.gov (United States)

    Mallow, Ole; Bolsinger, Jens; Finke, Pamela; Hesse, Malte; Chen, Yu-Sheng; Duthie, Andrew; Grabowsky, Simon; Luger, Peter; Mebs, Stefan; Beckmann, Jens

    2014-08-01

    The reaction of the intramolecularly coordinated diaryltellurium(IV) oxide (8-Me2NC10H6)2TeO with acetonitrile proceeds with oxygen transfer and gives rise to the formation of the novel zwitterionic diaryltelluronium(IV) acetimidate (8-Me2NC10H6)2TeNC(O)CH3 (1) in 57% yield. Hydrolysis of 1 with hydrochloric acid affords acetamide and the previously known diarylhydroxytelluronium(IV) chloride [(8-Me2NC10H6)2Te(OH)]Cl.

  8. The Unique Gas-Phase Chemistry of the [AuO](+) /CH4 Couple: Selective Oxygen-Atom Transfer to, Rather than Hydrogen-Atom Abstraction from, Methane.

    Science.gov (United States)

    Zhou, Shaodong; Li, Jilai; Schlangen, Maria; Schwarz, Helmut

    2016-08-26

    The thermal reaction of [AuO](+) with methane has been explored using FT-ICR mass spectrometry complemented by high-level quantum chemical calculations. In contrast to the previously studied congener [CuO](+) , and to [AgO](+) , [AuO](+) reacts with CH4 exclusively via oxygen-atom transfer to form CH3 OH, and a novel mechanistic scenario for this selective oxidation process has been revealed. Also, the origin of the inertness of the [AgO](+) /CH4 couple has been addressed computationally.

  9. Oxygen uncouples light absorption by the chlorosome antenna and photosynthetic electron transfer in the green sulfur bacterium Chlorobium tepidum

    DEFF Research Database (Denmark)

    Frigaard, N-U; Matsuura, K

    1999-01-01

    conditions decreased to approx. 3% of that under anaerobic conditions when BChl c was excited under light-limiting conditions. Photooxidation obtained by excitation of BChl a was similar under aerobic and anaerobic conditions. We interpret this drastic decrease in energy transfer from BChl c to the reaction......In photosynthetic green sulfur bacteria excitation energy is transferred from large bacteriochlorophyll (BChl) c chlorosome antennas via small BChl a antennas to the reaction centers which then transfer electrons from cytochrome c to low-potential iron-sulfur proteins. Under oxidizing conditions...... aurantiacus also contains chlorosomes but energy transfer from the BChl c and BChl a antennas to the reaction center in this species was not affected by O2....

  10. First half-reaction mechanism of nitric oxide synthase: the role of proton and oxygen coupled electron transfer in the reaction by quantum mechanics/molecular mechanics.

    Science.gov (United States)

    Cho, Kyung-Bin; Carvajal, Maria Angels; Shaik, Sason

    2009-01-08

    The first half-reaction of nitric oxide synthase (NOS) is investigated by means of quantum mechanical/molecular mechanical (QM/MM) calculations. An energetically feasible arginine hydroxylation path was found only when the iron-oxy complex accepted one proton from an external source. The so formed species has not been considered in heme chemistry; it is described as Por(+*)Fe(III)-OOH and is characterized by the same molecular constituency as the more known ferric-hydroperoxide species, compound 0, but has a cation-radical porphyrin moiety. The reaction itself is found to involve proton coupled electron transfer (PCET) and oxygen coupled electron transfer (OCET) steps en route to the formation of compound I and the ultimate monooxygenation of arginine. The cofactor H(4)B turns out to be a key player in the mechanism acting alternatively as an electron donor (when neutral) and an electron sink (when in its radical-cation state) and, thereby, providing the electron transfer component in the various coupled proton and oxygen transfer steps (see Scheme 4 ). The various pieces of this mechanism account for many of the experimental observations, such as the following: (a) the origins of the second proton supplied to the heme, (b) the elusiveness of compound I, (c) the inactivity of peroxide-shunt pathways in NOS first half-reaction, (d) the inhibition of the H(4)B analogue 4-amino-H(4)B due to protonation at the N3 position, (e) the roles of Trp188 (iNOS numbering) and the crystal water at the active site (W115), and so on. Alternative mechanistic hypotheses are tested and excluded, and a new mechanism for the NOS second half-reaction is proposed.

  11. Relation between utero-placental and feto-placental circulations: a longitudinal study.

    Science.gov (United States)

    Flo, Kari; Wilsgaard, Tom; Acharya, Ganesh

    2010-10-01

    To explore the relation between total utero-placental (TQ(uta)) and feto-placental (Q(uv)) blood flows and establish longitudinal reference ranges for the TQ(uta)/Q(uv) ratio and the mean uterine artery and umbilical artery pulsatility (UtaPI/UAPI) and resistance index (UtaRI/UARI) ratios. Prospective longitudinal observational study. University hospital in Norway. Fifty-three low-risk pregnant women. Uterine artery and umbilical vein blood flow was measured using Doppler ultrasonography at 4-weekly intervals from 22(+0) to 39(+6) weeks of gestation. Ratios between utero-placental and feto-placental volume blood flows and between indices of uterine and umbilical artery impedance. The TQ(uta)/Q(uv) ratio had a significant association with the gestational age (p feto-placental circulations do not appear to be affected by each other under physiological conditions. We have established longitudinal reference ranges for the utero-placental and feto-placental blood flow and impedance ratios during the second half of pregnancy.

  12. PPAR Signaling in Placental Development and Function.

    Science.gov (United States)

    Barak, Yaacov; Sadovsky, Yoel; Shalom-Barak, Tali

    2008-01-01

    With the major attention to the pivotal roles of PPARs in diverse aspects of energy metabolism, the essential functions of PPARgamma and PPARbeta/delta in placental development came as a surprise and were often considered a nuisance en route to their genetic analysis. However, these findings provided an opportune entrée into placental biology. Genetic and pharmacological studies, primarily of knockout animal models and cell culture, uncovered networks of PPARgamma and PPARdelta, their heterodimeric RXR partners, associated transcriptional coactivators, and target genes, that regulate various aspects of placental development and function. These studies furnish both specific information about trophoblasts and the placenta and potential hints about the functions of PPARs in other tissues and cell types. They reveal that the remarkable versatility of PPARs extends beyond the orchestration of metabolism to the regulation of cellular differentiation, tissue development, and trophoblast-specific functions. This information and its implications are the subject of this review.

  13. Confined placental mosaicism in short term culture

    Directory of Open Access Journals (Sweden)

    Petrović Bojana

    2016-01-01

    Full Text Available Finding of fetal chromosomal mosaicism complicates genetic counseling, as well as pregnancy management. The aim of this study was to determine the risk of confined placental mosaicism in short term culture of chorionic villous samples. We conducted a retrospective review of karyotype analysis results obtained after chorionic villous sampling (CVS in two years period. A 420 samples of chorionic villi were taken transabdominally and obtained by a semidirect method (overnight incubating culture. All fetuses with CVS mosaicism were under the intensive perinatal care. In all cases of chromosome mosaicism the additional karyotyping was performed from fetal blood samples after 22nd gestational week in order to exclude true fetal mosaicism. After delivery newborns were examined by experienced pediatrician. From 420 analyzed samples in 11 (2,6% cases we found placental mosaicism. No anomalies were seen in genetic sonogram of this fetuses and mosaicism was confirmed only in one case. Confined placental mosaicism (CPM was found in 2,1% (9/420 of all analyzed cases, and it made 90% of all placental mosaicism. In 60% (6/10 of placental mosaicism cases we found mosaicism with single aberrant cell. Trisomy 21 mosaicism was the most frequent aberration found in 30% of cases. Finding of mosaicism in chorionic villi sample is at special importance for genetic counseling, because every case has to be reveled individually regarding the type and level of mosaicism. Anyway, in every case of placental mosaicism intensive antenatal monitoring is necessary, with additional chromosome analysis from different tissue in consideration of previous findings.

  14. Short-term and long-term ethanol administration inhibits the placental uptake and transport of valine in rats

    Energy Technology Data Exchange (ETDEWEB)

    Patwardhan, R.V.; Schenker, S.; Henderson, G.I.; Abou-Mourad, N.N.; Hoyumpa, A.M. Jr.

    1981-08-01

    Ethanol ingestion during pregnancy causes a pattern of fetal/neonatal dysfunction called the FAS. The effects of short- and long-term ethanol ingestion on the placental uptake and maternal-fetal transfer of valine were studied in rats. The in vivo placental uptake and fetal uptake were estimated after injection of 0.04 micromol of /sub 14/C-valine intravenously on day 20 of gestation in Sprague-Dawley rats. Short-term ethanol ingestion (4 gm/kg) caused a significant reduction in the placental uptake of /sub 14/C-valine by 33%, 60%, and 30%, and 31% at 2.5, 5, 10, and 15 min after valine administration, respectively (p less than 0.01), and a similar significant reduction occurred in the fetal uptake of /sub 14/C-valine (p less than 0.01). Long-term ethanol ingestion prior to and throughout gestation resulted in a 47% reduction in placental valine uptake (p less than 0.01) and a 46% reduction in fetal valine uptake (p less than 0.01). Long-term ethanol feeding from day 4 to day 20 of gestation caused a 32% reduction in placental valine uptake (p less than 0.01) and a 26% reduction in fetal valine uptake (p less than 0.01). We conclude that both short- and long-term ingestion of ethanol inhibit the placental uptake and maternal-fetal transfer of an essential amino acid--valine. An alteration of placental function may contribute to the pathogenesis of the FAS.

  15. Determination of the oxygen transfer under clean water conditions and under operation conditions in membrane activated sludge systems; Messung und Auswertung des Sauerstoffeintrags in Reinwasser und unter Betriebsbedingungen in Membranbelebungsanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, M.; Cornel, P.; Krause, S. [Technische Hochschule Darmstadt (Germany). Inst. fuer Wasserversorgung, Abwasserbeseitigung und Raumplanung

    2001-04-01

    Because of the high quality of the effluent membranebioreactors are considered as alternative of conventional activated sludge treatment plants. In context concerning the {alpha}-value in membranebioreactors the article describes methods of measurement to determinate the oxygen transfer in clean and dirty water. There are no differences between membranebioreactors and activated sludge treatment plants in clean water tests. Because of the high biomass concentration and the difficulties in determination of the respiration rate differences to determine the oxygen transfer in activated sludge test are given compared to clean water conditions. In order to take influences of the oxygen saturation concentration into acount the proportion of oxygen transfer rate OTE{sub 20} should be taken for {alpha}-value determinations instead of the aeration coefficient k{sub L}a{sub 20}. (orig.)

  16. Placental ontogeny in Tasmanian snow skinks (genus Niveoscincus) (Lacertilia: Scincidae).

    Science.gov (United States)

    Stewart, James R; Thompson, Michael B

    2009-04-01

    Lizards of the viviparous genus Niveoscincus contributed importantly to a classic model for the evolution of placentation of squamate reptiles. This model predicts that: (1) placental function is correlated with placental structural complexity and (2) the type of chorioallantoic placenta attributed to three species of Niveoscincus (N. metallicus, N. ocellatus, N. pretiosus) is intermediate in complexity to a highly placentotrophic type of placenta. Recent studies of two of these species (N. metallicus, N. ocellatus) revealed additional variation in placental structure, as well as variation in the level of placentotrophy; N. metallicus is predominantly lecithotrophic, while N. ocellatus is highly placentotrophic. We used light microscopy to study placental ontogeny in two biennially reproducing species of Niveoscincus (N. greeni, N. microlepidotus) and placental morphology in late stage embryos of N. pretiosus. These data, in combination with prior studies, provide descriptions of placental structure for six of the eight species assigned to this lineage. The genus Niveoscincus has greater variation in placental structure than any other squamate lineage. We recognize four distinct groupings among these six species based on placental structure. The most highly placentotrophic species, N. ocellatus, has a complex placental morphology, yet shares these structures with a predominantly lecithotrophic species, N. microlepidotus. Thus, among species of Niveoscincus, placental structural complexity is not an infallible predictor of overall placental function.

  17. Quality assessment of a placental perfusion protocol

    DEFF Research Database (Denmark)

    Mathiesen, Line; Mose, Tina; Mørck, Thit Juul;

    2010-01-01

    the placental perfusion model in Copenhagen including control substances. The positive control substance antipyrine shows no difference in transport regardless of perfusion media used or of terms of delivery (n=59, pmarked dextran correspond with leakage criteria (...mlh(-1) from the fetal reservoir) when adding 2 (n=7) and 20mg (n=9) FITC-dextran/100ml fetal perfusion media. Success rate of the Copenhagen placental perfusions is provided in this study, including considerations and quality control parameters. Three checkpoints suggested to determine success rate...

  18. Ground-state oxygen holes and the metal-insulator transition in the negative charge-transfer rare-earth nickelates

    Science.gov (United States)

    Bisogni, Valentina; Catalano, Sara; Green, Robert J.; Gibert, Marta; Scherwitzl, Raoul; Huang, Yaobo; Strocov, Vladimir N.; Zubko, Pavlo; Balandeh, Shadi; Triscone, Jean-Marc; Sawatzky, George; Schmitt, Thorsten

    2016-10-01

    The metal-insulator transition and the intriguing physical properties of rare-earth perovskite nickelates have attracted considerable attention in recent years. Nonetheless, a complete understanding of these materials remains elusive. Here we combine X-ray absorption and resonant inelastic X-ray scattering (RIXS) spectroscopies to resolve important aspects of the complex electronic structure of rare-earth nickelates, taking NdNiO3 thin film as representative example. The unusual coexistence of bound and continuum excitations observed in the RIXS spectra provides strong evidence for abundant oxygen holes in the ground state of these materials. Using cluster calculations and Anderson impurity model interpretation, we show that distinct spectral signatures arise from a Ni 3d8 configuration along with holes in the oxygen 2p valence band, confirming suggestions that these materials do not obey a conventional positive charge-transfer picture, but instead exhibit a negative charge-transfer energy in line with recent models interpreting the metal-insulator transition in terms of bond disproportionation.

  19. A study of boiling heat transfer as applied to the cooling of ball bearings in the high pressure oxygen turbopump of the space shuttle main engine

    Science.gov (United States)

    Schreiber, Will

    1986-01-01

    Two sets of ball bearings support the main shaft within the High Pressure Oxygen Turbopump (HPOTP) in the Space Shuttle Main Engine (SSME). In operation, these bearings are cooled and lubricated with high pressure liquid oxygen (LOX) flowing axially through the bearing assembly. Currently, modifications in the assembly design are being contemplated in order to enhance the lifetime of the bearings and to allow the HPOTP to operate under larger loads. An understanding of the fluid dynamics and heat transfer characteristics of the flowing LOX is necessary for the implementation of these design changes. The proposed computational model of the LOX fluid dynamics, in addition to dealing with a turbulent flow in a complex geometry, must address the complication associated with boiling and two-phase flow. The feasibility of and possible methods for modeling boiling heat transfer are considered. The theory of boiling as pertains to this particular problem is reviewed. Recommendations are given for experiments which would be necessary to establish validity for correlations needed to model boiling.

  20. Redox control and hydrogen bonding networks: proton-coupled electron transfer reactions and tyrosine Z in the photosynthetic oxygen-evolving complex.

    Science.gov (United States)

    Keough, James M; Zuniga, Ashley N; Jenson, David L; Barry, Bridgette A

    2013-02-07

    In photosynthetic oxygen evolution, redox active tyrosine Z (YZ) plays an essential role in proton-coupled electron transfer (PCET) reactions. Four sequential photooxidation reactions are necessary to produce oxygen at a Mn(4)CaO(5) cluster. The sequentially oxidized states of this oxygen-evolving cluster (OEC) are called the S(n) states, where n refers to the number of oxidizing equivalents stored. The neutral radical, YZ•, is generated and then acts as an electron transfer intermediate during each S state transition. In the X-ray structure, YZ, Tyr161 of the D1 subunit, is involved in an extensive hydrogen bonding network, which includes calcium-bound water. In electron paramagnetic resonance experiments, we measured the YZ• recombination rate, in the presence of an intact Mn(4)CaO(5) cluster. We compared the S(0) and S(2) states, which differ in Mn oxidation state, and found a significant difference in the YZ• decay rate (t(1/2) = 3.3 ± 0.3 s in S(0); t(1/2) = 2.1 ± 0.3 s in S(2)) and in the solvent isotope effect (SIE) on the reaction (1.3 ± 0.3 in S(0); 2.1 ± 0.3 in S(2)). Although the YZ site is known to be solvent accessible, the recombination rate and SIE were pH independent in both S states. To define the origin of these effects, we measured the YZ• recombination rate in the presence of ammonia, which inhibits oxygen evolution and disrupts the hydrogen bond network. We report that ammonia dramatically slowed the YZ• recombination rate in the S(2) state but had a smaller effect in the S(0) state. In contrast, ammonia had no significant effect on YD•, the stable tyrosyl radical. Therefore, the alterations in YZ• decay, observed with S state advancement, are attributed to alterations in OEC hydrogen bonding and consequent differences in the YZ midpoint potential/pK(a). These changes may be caused by activation of metal-bound water molecules, which hydrogen bond to YZ. These observations document the importance of redox control in proton

  1. Thermodynamics of electron transfer in oxygenic photosynthetic reaction centers: volume change, enthalpy, and entropy of electron-transfer reactions in manganese-depleted photosystem II core complexes.

    Science.gov (United States)

    Hou, J M; Boichenko, V A; Diner, B A; Mauzerall, D

    2001-06-19

    We have previously reported the thermodynamic data of electron transfer in photosystem I using pulsed time-resolved photoacoustics [Hou et al. (2001) Biochemistry 40, 7109-7116]. In the present work, using preparations of purified manganese-depleted photosystem II (PS II) core complexes from Synechocystis sp. PCC 6803, we have measured the DeltaV, DeltaH, and estimated TDeltaS of electron transfer on the time scale of 1 micros. At pH 6.0, the volume contraction of PS II was determined to be -9 +/- 1 A3. The thermal efficiency was found to be 52 +/- 5%, which corresponds to an enthalpy change of -0.9 +/- 0.1 eV for the formation of the state P680+Q(A-) from P680*. An unexpected volume expansion on pulse saturation of PS II was observed, which is reversible in the dark. At pH 9.0, the volume contraction, the thermal efficiency, and the enthalpy change were -3.4 +/- 0.5 A3, 37 +/- 7%, and -1.15 +/- 0.13 eV, respectively. The DeltaV of PS II, smaller than that of PS I and bacterial centers, is assigned to electrostriction and analyzed using the Drude-Nernst equation. To explain the small DeltaV for the formation of P680+Q(A-) or Y(Z*)Q(A-), we propose that fast proton transfer into a polar region is involved in this reaction. Taking the free energy of charge separation of PS II as the difference between the energy of the excited-state P680* and the difference in the redox potentials of the donor and acceptor, the apparent entropy change (TDeltaS) for charge separation of PS II is calculated to be negative, -0.1 +/- 0.1 eV at pH 6.0 (P680+Q(A-)) and -0.2 +/- 0.15 eV at pH 9.0 (Y(Z*)Q(A-)). The thermodynamic properties of electron transfer in PS II core reaction centers thus differ considerably from those of bacterial and PS I reaction centers, which have DeltaV of approximately -27 A3, DeltaH of approximately -0.4 eV, and TDeltaS of approximately +0.4 eV.

  2. Placental lesions and outcome in preterm born children : the relation between placental lesions, neonatal morbidity and neurological development

    NARCIS (Netherlands)

    Roescher, Annemiek

    2014-01-01

    The placenta is the link between the mother and her fetus during pregnancy and plays a crucial role in fetal growth and development. A less than optimal placental function as a result of placental lesions, may lead to maternal and or fetal problems. It is known that placental lesions are an importan

  3. Recombinant expression of placental growth factor in baculovirus expression system

    Directory of Open Access Journals (Sweden)

    Narges Arbabi

    2016-12-01

    Full Text Available Background: Angiogenesis or formation of new blood vessels is the most important factor in physiological and pathological conditions. Human Placental growth factor (hPLGF protein in is one of the most important proteins which stimulate angiogenesis. Baculovirus expression system has been used successfully to over express eukaryotic proteins in insect cells. This system uses a very strong viral promoter, AcNPV polyhedrin, for high level of protein expression. Methods: hPLGF gene cloned in pFastBac-HT vector and transformed in DH10Bac.The recombinant bacmid was extracted and used in SF9 insect cells and transfected by cellfectin method. Target protein expression was confirmed with Western blot. Results: Transferring of the recombinant vector into Bacmid was successful and the PLGF gene sequence was confirmed. PLGF and recombinant protein expression by Western blotting was confirmed. Conclusion: Baculovirus protein expression system expresses PLGF strongly and recombinant protein can be used in different tests.

  4. Oxygenation of the placenta and its role in pre-eclampsia.

    Science.gov (United States)

    Huppertz, Berthold

    2014-07-01

    Proper oxygenation of the placenta and hence the embryo/fetus is essential for a successful pregnancy. During the first trimester of pregnancy the partial pressure of oxygen in the placenta and the embryo is very low and does not exceed 20mmHg. At the end of the first trimester maternal blood flow towards the placenta is established leading to a sudden increase in placental oxygenation to about 50-60mmHg. This level of oxygenation is keptuntil delivery. One of the numerous hypotheses to describe the etiology of preeclampsia, which is still the most cited hypothesis today, is based on a failure of extravillous trophoblast to invade the uterine spiral arteries in the placental bed. This in turn is believed to result in placental hypoxia and subsequently to damage of the villous trophoblast. Following this hypothesis, there is a series of events following these hypoxic conditions of the placenta. There is a large number of articles published that have investigated the effect of different oxygen concentrations on the phenotype of trophoblasts in vitro and have used this data to corroborate the hypothesis above. Unfortunately, one important aspect has not been addressed until recently: What is the placental oxygen concentration in placental pathologies such as preeclampsia in vivo? All studies that have tried to elucidate the placental oxygen concentration have done this indirectly, since direct measurements of placental oxygen in the third trimester of pregnancy have been defined as unethical. Not a single of such studies has revealed that oxygenation of the placenta in pregnancy pathologies is decreased. At the same time a number of studies have shown that in intra-uterine growth restriction (IUGR) placental oxygenation is increased rather than decreased. This has been shown to be true in the presence and absence of preeclampsia. This data clearly disprove the above hypothesis and should open our minds to decipherthe realcauses of preeclampsia.

  5. Placental Development in Ongoing Pregnancy and Miscarriage

    NARCIS (Netherlands)

    A.D. Reus (Averil)

    2015-01-01

    markdownabstract__Abstract__ In this thesis three-dimensional ultrasound, three-dimensional power Doppler ultrasound, virtual reality and histologic examination of the chorionic villous vascularization were used to investigate early placental development in normal ongoing pregnancy as well as misca

  6. A RADIOIMMUNOASSAY FOR PLACENTAL PROTEIN PP5

    Institute of Scientific and Technical Information of China (English)

    WANGShui-Long; DUGuo-Guang; ZHENGShu-Rong; LIUXin-Jun; YANRen-Ying

    1989-01-01

    A radioimmunoasay of high sendtivity end smbility was developed For placental proteinPP5 (PP5), a syncytiotrophoblast product oF the human placenta. We measured 94 samples from 17 normal nonpregnant women, 47 normal pregnant women, and 30 samples

  7. Placental specializations in lecithotrophic viviparous squamate reptiles.

    Science.gov (United States)

    Stewart, James R

    2015-09-01

    Squamate reptiles have been thought to be predisposed to evolution of viviparity because embryos of most oviparous species undergo considerable development in the uterus prior to oviposition. A related hypothesis proposes that prolonged intrauterine gestation, an intermediate condition leading to viviparity, requires little or no physiological adjustment, other than reduction in thickness of the eggshell. This logical framework is often accompanied by an assumption that mode of parity (oviparity, viviparity) and pattern of embryonic nutrition (lecithotrophy, placentotrophy) are independent traits that evolve in sequence. Thus, specializations for viviparity should be absent in some lecithotrophic viviparous species. Studies of species of lizards with geographic variation in mode of parity challenge this scenario by demonstrating that placental specializations are correlated with viviparity. Uterine specializations for placental transport of calcium to viviparous embryos alter uterine physiology compared to oviparous females. In addition, comparative studies of oviparous and viviparous species, i.e., in which gene flow is disrupted, reveal that both uterine and embryonic structural modifications are commonly associated with viviparity, suggesting relatively rapid evolution of placental specializations. Studies of squamate reproductive biology support two hypotheses: 1) evolution of viviparity requires physiological adjustments of the uterine environment, and 2) evolution of viviparity promotes relatively rapid adaptations for placentation. Models for the evolution of viviparity from oviparity, or for reversals from viviparity to oviparity, should reflect current understanding of squamate reproductive biology and future studies should be designed to challenge these models.

  8. Pregnancy Complications: Placental Accreta, Increta and Percreta

    Science.gov (United States)

    ... Being 35 or older Being pregnant before Having placenta previa How can you reduce your risk for placental conditions? One way to reduce your chances for having these ... In some cases, the placenta doesn’t develop correctly or work as well ...

  9. Placental Malaria: From Infection to Malfunction

    OpenAIRE

    2013-01-01

    Malaria during pregnancy is a major factor in infant morbidity and mortality. In this issue of Cell Host and Microbe, Conroy et al. (2013) propose that C5a, a product of complement cascade activation, counteracts the placental vascular remodeling response induced by Plasmodium infection and contributes to fetal growth restriction. Fundação para a Ciência e Tecnologia.

  10. Placental Mesenchymal Dysplasia: A Case Report

    Directory of Open Access Journals (Sweden)

    Rachna Agarwal

    2012-01-01

    Full Text Available Introduction. A rare case of histologically proven placental mesenchymal dysplasia (PMD with fetal omphalocele in a 22-year-old patient is reported. Material and Methods. Antenatal ultrasound of this patient showed hydropic placenta with a live fetus of 17 weeks period of gestation associated with omphalocele. Cordocentesis detected the diploid karyotype of the fetus. Patient, when prognosticated, choose to terminate the pregnancy in view of high incidence of fetal and placental anomalies. Subsequent histopathological examination of placenta established the diagnosis to be placental mesenchymal dysplasia. Conclusion. On clinical and ultrasonic grounds, suspicion of P.M.D. arises when hydropic placenta with a live fetus presents in second trimester of pregnancy. Cordocentesis can detect the diploid karyotype of the fetus in such cases. As this condition is prognostically better than triploid partial mole, continuation of pregnancy can sometimes be considered after through antenatal screening and patient counseling. However, a definite diagnosis of P.M.D. is made only on placental histology by absence of trophoblast hyperplasia and trophoblastic inclusions.

  11. Invasión trofoblástica en el embarazo normal (II: Placentación profunda (Trophoblastic invasion in normal pregnancy (II: Deep placentation

    Directory of Open Access Journals (Sweden)

    Eduardo Reyna-Villasmil

    2015-01-01

    Full Text Available Deep placentation in human pregnancy is done by deep invasion of the placental bed by the extravillous trophoblast, involving the decidua and the inner (junctional zone myometrium. Interstitial invasion of the stroma and endovascular trophoblast invasion of the spiral arteries both occur. Deep endovascular trophoblast invasion into the myometrial segments of spiral arteries is important for proper placental functioning. Decidua-associated vascular remodeling, which includes swelling and disorganization of the vascular smooth muscle, occurs during a period of rising placental oxygen. This early remodeling step may accommodate the progressively increasing maternal blood flow to the developing placenta. The subsequent trophoblast-associated remodeling step enhances and stabilizes the widening of the vessels, whereas the vascular smooth muscle and elastic lamina are replaced by a fibrinoid matrix with embedded trophoblast

  12. Successful 2,000-Kilometer International Transfer of an Infant Receiving Extracorporeal Membrane Oxygenation for Severe Respiratory Failure.

    Science.gov (United States)

    Brown, Kilian; Dunne, Ben; Festa, Marino; La Hei, Erik; Karpelowsky, Jonathan; Dando, Hayden; Orr, Yishay

    2016-08-01

    There is minimal reported experience with long-range retrieval of pediatric patients receiving extracorporeal membrane oxygenation (ECMO) support. We report the case of a 10-month old boy with necrotizing staphylococcal pneumonia complicated by a bronchopleural fistula, who was successfully retrieved and transported while receiving ECMO to our unit in Sydney, Australia, from a referring hospital 2,000 kilometers away in the Pacific Islands. He was successfully weaned from ECMO to receive single-lung ventilation after 13 days, and he underwent surgical repair of his bronchopleural fistula through a thoracotomy 3 days after decannulation. He has made a full recovery.

  13. Hypoxia and Reoxygenation: a Possible Mechanism for Placental Oxidative Stress in Preeclampsia

    Directory of Open Access Journals (Sweden)

    Tai-Ho Hung

    2006-09-01

    Full Text Available Preeclampsia is a human pregnancy-specific disorder that is diagnosed by the new appearance of hypertension and proteinuria after 20 weeks' gestation. It is a leading cause of perinatal morbidity and mortality, and the only intervention that effectively reverses the syndrome is delivery. Oxidative stress of the placenta is considered to be a key intermediary step in the pathogenesis of preeclampsia, but the cause for the stress remains unknown. Hypoxia-reoxygenation (H/R injury, as a result of intermittent placental perfusion secondary to deficient trophoblast invasion of the endometrial arteries, is a possible mechanism. In this review, we present evidence to show that there is a plausible basis from which to assume that blood flow in the intervillous space will be intermittent in all normal pregnancies. The intermittency will be exacerbated by impaired conversion of the spiral arteries, or by the presence of atherotic changes that reduce their caliber as seen in preeclampsia. Placental oxidative stress can be the consequences of fluctuations in oxygen concentrations after H/R through the actions of reactive oxygen species. On this basis, there will be a complete spectrum of placental changes among the normal, the late onset and the early onset preeclamptic states. Viewing the syndrome as a continuum of H/R insults provides new insight into the pathophysiology of pregnancy that will hopefully lead to improved clinical interventions.

  14. High-yield production of biologically active recombinant protein in shake flask culture by combination of enzyme-based glucose delivery and increased oxygen transfer

    Directory of Open Access Journals (Sweden)

    Ukkonen Kaisa

    2011-12-01

    Full Text Available Abstract This report describes the combined use of an enzyme-based glucose release system (EnBase® and high-aeration shake flask (Ultra Yield Flask™. The benefit of this combination is demonstrated by over 100-fold improvement in the active yield of recombinant alcohol dehydrogenase expressed in E. coli. Compared to Terrific Broth and ZYM-5052 autoinduction medium, the EnBase system improved yield mainly through increased productivity per cell. Four-fold increase in oxygen transfer by the Ultra Yield Flask contributed to higher cell density with EnBase but not with the other tested media, and consequently the product yield per ml of EnBase culture was further improved.

  15. Oxygen mass transfer in moving bed biofilm reactor%移动床生物膜反应器中的氧传质性能

    Institute of Scientific and Technical Information of China (English)

    花吉锋; 李文英; 荆洁颖; 孙梦君; 李静

    2012-01-01

    Aimed at enhancing oxygen mass transfer efficiency in moving bed biofilm reactor,the influences of effect factors on oxygen mass transfer coefficient(KLa) have been studied by dynamic oxygen dissolution method,including intensity of aeration(0.84-4.2 m3/h),carrier stuffing rate(0-30%),reactor height(0-0.5 m),added surfactant(sodium dodecyl sulfate) and electrolyte(NaCl).The result shows that KLa increases from 0.002 5 to 0.066/s with the increase of aeration intensity and oxygen mass transfer performs the best in 10% carrier stuffing rate.Reactor height affects the gas-liquid transfer area through the change of pressure,leading to KLa gradually decreasing from 0.011 to 0.009 6 s-1 when gas bubble rises to liquid surface.Adding surfactant into distilled water,KLa decreases during its concentration range,0-0.015 g/L.NaCl added plays a significant role in variation of gas bubble's ζ potential and surface tension,as a result of KLa increasing in NaCl concentration range of 0-20 g/L.%为提高移动床生物膜反应器中氧传质效率,利用动态溶氧法测定曝气量(0.84~4.2m3/h)、填料填充率(0~30%)、反应器高度(0~0.5m)、溶液中添加表面活性剂十二烷基硫酸钠和电解质NaCl等因素对氧传质系数的影响,结果表明随着曝气量的增大,氧传质系数从0.002 5/s增加到0.066/s,填料固含率在10%时氧传质效果最好;反应器高度主要影响气泡的压力进而影响气液接触面积,随着气泡的上升,氧传质系数从0.011逐渐降低为0.009 6/s;表面活性剂在0~0.015g/L浓度范围内氧传质系数逐渐降低;NaCl通过改变气泡表面的ζ电势和表面张力进而影响氧传质效果,在0~20g/L范围内,氧传质系数随着NaCl浓度的增大而增大.

  16. A manganese(V)-oxo π-cation radical complex: influence of one-electron oxidation on oxygen-atom transfer.

    Science.gov (United States)

    Prokop, Katharine A; Neu, Heather M; de Visser, Sam P; Goldberg, David P

    2011-10-12

    One-electron oxidation of Mn(V)-oxo corrolazine 2 affords 2(+), the first example of a Mn(V)(O) π-cation radical porphyrinoid complex, which was characterized by UV-vis, EPR, LDI-MS, and DFT methods. Access to 2 and 2(+) allowed for a direct comparison of their reactivities in oxygen-atom transfer (OAT) reactions. Both complexes are capable of OAT to PPh(3) and RSR substrates, and 2(+) was found to be a more potent oxidant than 2. Analysis of rate constants and activation parameters, together with DFT calculations, points to a concerted OAT mechanism for 2(+) and 2 and indicates that the greater electrophilicity of 2(+) likely plays a dominant role in enhancing its reactivity. These results are relevant to comparisons between Compound I and Compound II in heme enzymes.

  17. Inhibition of photosynthetic oxygen evolution and electron transfer from the quinone acceptor QA- to QB by iron deficiency.

    Science.gov (United States)

    Msilini, Najoua; Zaghdoudi, Maha; Govindachary, Sridharan; Lachaâl, Mokhtar; Ouerghi, Zeineb; Carpentier, Robert

    2011-03-01

    The effect of iron deficiency on photosynthetic electron transport in Photosystem II (PS II) was studied in leaves and thylakoid membranes of lettuce (Lactuca sativa, Romaine variety) plants. PS II electron transport was characterized by oxygen evolution and chlorophyll fluorescence parameters. Iron deficiency in the culture medium was shown to affect water oxidation and the advancement of the S-states. A decrease of maximal quantum yield of PS II and an increase of fluorescence intensity at step J and I of OJIP kinetics were also observed. Thermoluminescence measurements revealed that charge recombination between the quinone acceptor of PS II, Q(B), and the S(2) state of the Mn-cluster was strongly perturbed. Also the dark decay of Chl fluorescence after a single turnover white flash was greatly retarded indicating a slower rate of Q(A)(-) reoxidation.

  18. A flexible well-mixed milliliter-scale reactor with high oxygen transfer rate for microbial cultivations

    DEFF Research Database (Denmark)

    Bolic, Andrijana; Larsson, Hilde Kristina; Hugelier, Siewert;

    2016-01-01

    In order to choose the best strain and subsequently develop an optimal bioprocess many experiments need to be performed. Usually this process is expensive and labor intensive with a limited amount of data available. Small-scale bioreactors and high-throughput platforms are becoming an attractive...... solution and replacement for existing microtiter plates, shaken flasks and bench scale bioreactors. In this work, a new design of a milliliter-scale bioreactor system is presented and characterized. The entire system consists of a platform with gas connections, heater, temperature sensor and optical fibers...... on the one side and a bioreactor with special designed magnetic stirrer and non-invasive optical sensors for measurement of pH, dissolved oxygen and optical density on the other side. The system has a high level of flexibility in terms of volume (0.5–2 mL), aeration (sparging and surface aeration) and mixing...

  19. Evaluation of gene expression and alginate production in response to oxygen transfer in continuous culture of Azotobacter vinelandii.

    Directory of Open Access Journals (Sweden)

    Alvaro Díaz-Barrera

    Full Text Available Alginates are polysaccharides used as food additives and encapsulation agents in biotechnology, and their functional properties depend on its molecular weight. In this study, different steady-states in continuous cultures of A. vinelandii were established to determine the effect of the dilution rate (D and the agitation rate on alginate production and expression of genes involved in alginate polymerization and depolymerization. Both, the agitation and dilution rates, determined the partitioning of the carbon utilization from sucrose into alginate and CO2 under oxygen-limiting conditions. A low D (0.07 h(-1 and 500 rpm resulted in the highest carbon utilization into alginate (25%. Quantitative real-time polymerase chain reaction was used to determine the transcription level of six genes involved in alginate polymerization and depolymerization. In chemostat cultures at 0.07 h(-1, the gene expression was affected by changes in the agitation rate. By increasing the agitation rate from 400 to 600 rpm, the algE7 gene expression decreased tenfold, whereas alyA1, algL and alyA2 gene expression increased between 1.5 and 2.8 times under similar conditions evaluated. Chemostat at 0.07 h(-1 showed a highest alginate molecular weight (580 kDa at 500 rpm whereas similar molecular weights (480 kDa were obtained at 400 and 600 rpm. The highest molecular weight was not explained by changes in the expression of alg8 and alg44 (genes involved in alginate polymerization. Nonetheless, a different expression pattern observed for lyases could explain the highest alginate molecular weight obtained. Overall, the results suggest that the control of alginate molecular weight in A. vinelandii cells growing in continuous mode is determined by a balance between the gene expression of intracellular and extracellular lyases in response to oxygen availability. These findings better our understanding of the biosynthesis of bacterial alginate and help us progress toward obtain

  20. Evaluation of Gene Expression and Alginate Production in Response to Oxygen Transfer in Continuous Culture of Azotobacter vinelandii

    Science.gov (United States)

    Díaz-Barrera, Alvaro; Martínez, Fabiola; Guevara Pezoa, Felipe; Acevedo, Fernando

    2014-01-01

    Alginates are polysaccharides used as food additives and encapsulation agents in biotechnology, and their functional properties depend on its molecular weight. In this study, different steady-states in continuous cultures of A. vinelandii were established to determine the effect of the dilution rate (D) and the agitation rate on alginate production and expression of genes involved in alginate polymerization and depolymerization. Both, the agitation and dilution rates, determined the partitioning of the carbon utilization from sucrose into alginate and CO2 under oxygen-limiting conditions. A low D (0.07 h−1) and 500 rpm resulted in the highest carbon utilization into alginate (25%). Quantitative real-time polymerase chain reaction was used to determine the transcription level of six genes involved in alginate polymerization and depolymerization. In chemostat cultures at 0.07 h−1, the gene expression was affected by changes in the agitation rate. By increasing the agitation rate from 400 to 600 rpm, the algE7 gene expression decreased tenfold, whereas alyA1, algL and alyA2 gene expression increased between 1.5 and 2.8 times under similar conditions evaluated. Chemostat at 0.07 h−1 showed a highest alginate molecular weight (580 kDa) at 500 rpm whereas similar molecular weights (480 kDa) were obtained at 400 and 600 rpm. The highest molecular weight was not explained by changes in the expression of alg8 and alg44 (genes involved in alginate polymerization). Nonetheless, a different expression pattern observed for lyases could explain the highest alginate molecular weight obtained. Overall, the results suggest that the control of alginate molecular weight in A. vinelandii cells growing in continuous mode is determined by a balance between the gene expression of intracellular and extracellular lyases in response to oxygen availability. These findings better our understanding of the biosynthesis of bacterial alginate and help us progress toward obtain tailor

  1. Quenching of electron transfer reactions through coadsorption: A study of oxygen photodesorption from TiO2(110)

    Science.gov (United States)

    Petrik, Nikolay G.; Kimmel, Greg A.; Shen, Mingmin; Henderson, Michael A.

    2016-10-01

    Using temperature programmed desorption (TPD) and photon-stimulated desorption (PSD), we show that coadsorbates of varying binding energies on the rutile TiO2(110) surface exert a commensurate inhibiting influence on the hole-mediated photodesorption of adsorbed O2. A variety of coadsorbates (Ar, Kr, Xe, N2, CO, CO2, CH4, N2O, acetone, methanol or water) were shown to quench O2 photoactivity, with the extent correlating with the coadsorbate's gas phase basicity, which in turn determines the strength of the coadsorbate-Ti4 + bond. Coadsorbed rare gases inhibited the photodesorption of O2 by ~ 10-25%, whereas strongly bound species (water, methanol, and acetone) nearly completely inhibited O2 PSD. We suggest that coadsorption of these molecules inhibit the arrival probability of holes to the surface. Band-bending effects, which vary with the extent of charge transfer between the coadsorbate and the TiO2(110) surface, are not expected to be significant in the cases of the rare gases and physisorbed species. These results indicate that neutral coadsorbates can exert a significant influence on charge transfer events by altering the interfacial dipole in the vicinity of the target molecule.

  2. Doppler indicates of uterine artery Doppler velocimetry by placental location

    Energy Technology Data Exchange (ETDEWEB)

    Han, Sung Shik; Park, Yong Won; Cho, Jae Sung; Kwon, Hye Kyeung; Kim, Jae Wook [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2001-09-15

    Our purpose was to investigate the relation between the vascular resistance of uterine artery and placental location and to establish the reference value of Doppler index in uterine artery by placental location. Placental location and flow velocity waveforms of both uterine arteries in 7,016 pregnant women after 18 weeks gestation were examined using color Doppler ultrasonography. Placental location was classified as central and lateral placental and the uterine artery with lateral placental were divided into ipsilateral uterine artery (same side of the placental) and contralateral uterine artery (opposite side of the placenta). The uterine artery with central placental was classified as the central uterine artery. Systolic-Diastolic ratio (S/D ratio) of uterine arteries by gestational weeks were calculated and compared with the placental location and perinatal outcomes. In the lateral placental group, the S/D ratio of the contralateral uterine artery was higher than the ipsilateral one (mean=2.08+0.34 vs 1.89+0.34, p=0.0001). S/D ratio of the uterine artery decreased during second trimester and the ratio after 27 weeks was a tendency to have a constant values(ipsilateral: 1.85+ 0.34, central : 1.96+ 0.40, contralateral: 2.01+0.54). S/D ratio of the uterine artery was affected by placental location. So when we evaluate Doppler spectrum of uterine artery, placental location should be considered and we established the reference value of Doppler index of uterine artery by placental location.

  3. Mono-2-ethylhexyl phthalate induces oxidative stress responses in human placental cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Tetz, Lauren M., E-mail: ltetz@umich.edu [Department of Environmental Health Sciences, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109-2029 (United States); Cheng, Adrienne A.; Korte, Cassandra S. [Department of Environmental Health Sciences, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109-2029 (United States); Giese, Roger W.; Wang, Poguang [Department of Pharmaceutical Sciences, Northeastern University, 360 Huntingon Ave, Boston, MA 02115 (United States); Harris, Craig; Meeker, John D.; Loch-Caruso, Rita [Department of Environmental Health Sciences, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109-2029 (United States)

    2013-04-01

    Di-2-ethylhexyl phthalate (DEHP) is an environmental contaminant commonly used as a plasticizer in polyvinyl chloride products. Exposure to DEHP has been linked to adverse pregnancy outcomes in humans including preterm birth, low birth-weight, and pregnancy loss. Although oxidative stress is linked to the pathology of adverse pregnancy outcomes, effects of DEHP metabolites, including the active metabolite, mono-2-ethylhexyl phthalate (MEHP), on oxidative stress responses in placental cells have not been previously evaluated. The objective of the current study is to identify MEHP-stimulated oxidative stress responses in human placental cells. We treated a human placental cell line, HTR-8/SVneo, with MEHP and then measured reactive oxygen species (ROS) generation using the dichlorofluorescein assay, oxidized thymine with mass-spectrometry, redox-sensitive gene expression with qRT-PCR, and apoptosis using a luminescence assay for caspase 3/7 activity. Treatment of HTR-8 cells with 180 μM MEHP increased ROS generation, oxidative DNA damage, and caspase 3/7 activity, and resulted in differential expression of redox-sensitive genes. Notably, 90 and 180 μM MEHP significantly induced mRNA expression of prostaglandin-endoperoxide synthase 2 (PTGS2), an enzyme important for synthesis of prostaglandins implicated in initiation of labor. The results from the present study are the first to demonstrate that MEHP stimulates oxidative stress responses in placental cells. Furthermore, the MEHP concentrations used were within an order of magnitude of the highest concentrations measured previously in human umbilical cord or maternal serum. The findings from the current study warrant future mechanistic studies of oxidative stress, apoptosis, and prostaglandins as molecular mediators of DEHP/MEHP-associated adverse pregnancy outcomes. - Highlights: ► MEHP increased reactive oxygen species, oxidative DNA damage, and caspase activity. ► MEHP induced expression of PTGS2, a gene

  4. Simultaneous determination of acrylamide, its metabolite glycidamide and antipyrine in human placental perfusion fluid and placental tissue by liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Annola, Kirsi; Keski-Rahkonen, Pekka; Vähäkangas, Kirsi; Lehtonen, Marko

    2008-12-15

    A rapid and sensitive method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the simultaneous determination of acrylamide (AA) and its genotoxic metabolite glycidamide (GA) with a test marker antipyrine (AP) in placental tissue and perfusion medium used in human placental perfusion studies. An internal standard ((13)C-acrylamide) was added to the samples which were then deproteinized with acetonitrile. Chromatographic separation was performed on a reversed phase column with a gradient elution of acetonitrile and 0.01% formic acid at a flow rate of 0.3 mL/min. Detection and quantification of the analytes were carried out with a triple quadrupole mass spectrometer using positive electrospray ionization (ESI) and multiple reaction monitoring (MRM). The method was validated and linear over a concentration range of 0.5-20 microg/mL for acrylamide and glycidamide and 5-200 microg/mL for antipyrine. The lower limit of quantification for acrylamide and glycidamide was 0.5 microg/mL and for antipyrine 5 microg/mL. The method was selective, and good accuracy, precision, recovery, and stability were obtained for concentrations within the standard curve. The method was successfully used to analyze the placental perfusion medium and tissue samples in a toxicokinetic study for transplacental transfer of acrylamide and glycidamide. This is the first time that acrylamide, glycidamide and antipyrine are measured simultaneously.

  5. Quenching of electron transfer reactions through coadsorption: A study of oxygen photodesorption from TiO2(110)

    Energy Technology Data Exchange (ETDEWEB)

    Petrik, Nikolay G.; Kimmel, Gregory A.; Shen, Mingmin; Henderson, Michael A.

    2016-10-01

    Using temperature programmed desorption (TPD) and photon stimulated desorption (PSD), we show that coadsorbates of varying binding energies on the rutile TiO2(110) surface exert a commensurate inhibiting influence on the hole-mediated photodesorption of adsorbed O2. A variety of coadsorbates (Ar, Kr, Xe, N2, CO, CO2, CH4, N2O, acetone, methanol or water) were shown to quench O2 photoactivity, with the extent correlating with the coadsorbate’s gas phase basicity, which in turn determines the strength of the coadsorbate-Ti4+ bond. Coadsorbed rare gases inhibited the photodesorption of O2 by ~10-25%, whereas strongly bound species (water, methanol and acetone) nearly completely inhibited O2 PSD. We suggest that coadsorption of these molecules inhibit the arrival probability of holes to the surface. Band bending effects, which vary with the extent of charge transfer between the coadsorbate and the TiO2(110) surface, are not expected to be significant in the cases of the rare gases and physisorbed species. These results indicate that neutral coadsorbates can exert a significant influence on charge transfer events by altering the interfacial dipole in the vicinity of the target molecule. This work was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. The work was performed using EMSL, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is a multiprogram national laboratory operated for DOE by Battelle under Contract DE-AC05-76RL01830.

  6. Human placental lactogen and intrauterine growth retardation.

    Science.gov (United States)

    Spellacy, W N; Buhi, W C; Birk, S A

    1976-04-01

    Serum human placental lactogen levels were measured after 36 weeks' gestation in 264 serum samples from 109 women with normal pregnancies and in 137 serum samples from 70 women with pregnancies complicated by fetal intrauterine growth retardation (IGR). The fetal and placental weights were significantly lower in the IGR groups while the maternal ages were not different. There was a significantly lower hPL value at each week from 36 to 41 (except for the 39th) in the IGR group. Sixty percent of the women with IGR had hPL values less than 6 mug/ml, and 18.6% were less than 4 mug/ml. It is suggested that a low serum hPL value obtained during the last month of pregnancy should alert the physician to the possibility of intrauterine problems, including IGR.

  7. Neurotrophins: Role in Placental Growth and Development.

    Science.gov (United States)

    Sahay, A S; Sundrani, D P; Joshi, S R

    2017-01-01

    Neurotrophins, a family of closely related proteins, were originally identified as growth factors for survival, development, and function of neurons in both the central and peripheral nervous systems. Subsequently, neurotrophins have been shown to have functions in immune and reproductive systems. Neurotrophins like nerve growth factor and brain-derived neurotrophic factor (BDNF) are known to play an important role during pregnancy in the process of placental angiogenesis and maturation. Several studies have demonstrated the presence of neurotrophins in the human placenta. The current chapter reviews studies demonstrating the role of neurotrophins during pregnancy particularly in placental development. This chapter also focuses on the regional changes in neurotrophins in the human placenta and its interactions with other growth factors. Future research is needed to understand the mechanisms through which neurotrophins influence the growth and development of the placenta and pregnancy outcome.

  8. Placentation in the Amazonian manatee (Trichechus inunguis)

    DEFF Research Database (Denmark)

    Carter, A M; Miglino, M A; Ambrosio, C E;

    2008-01-01

    Evidence from several sources supports a close phylogenetic relationship between elephants and sirenians. To explore whether this was reflected in similar placentation, we examined eight delivered placentae from the Amazonian manatee using light microscopy and immunohistochemistry. In addition......, the fetal placental circulation was described by scanning electron microscopy of vessel casts. The manatee placenta was zonary and endotheliochorial, like that of the elephant. The interhaemal barrier comprised maternal endothelium, cytotrophoblasts and fetal endothelium. We found columnar trophoblast...... beneath the chorionic plate and lining lacunae in this region, but there was no trace in the term placenta of haemophagous activity. The gross anatomy of the cord and fetal membranes was consistent with previous descriptions and included a four-chambered allantoic sac, as also found in the elephant...

  9. Placental transfer of ruthenium in rat and guinea-pig

    Energy Technology Data Exchange (ETDEWEB)

    Levack, V.M.; Pottinger, H.; Harrison, J.D. [National Radiological Protection Board, Chilton (United Kingdom)

    1994-12-01

    Ruthenium-106 in citrate solution was administered intravenously to rat at different stages of pregnancy and to guinea-pig either before conception or in late pregnancy. The results for rat showed that retention in the embryo/foetus measured at 3-5 days after administration increased from about 0.0002% of injected activity per embryo/foetus on day 12 of gestation to about 0.05% at birth. The relative concentrations of {sup 106}Ru in embryo/foetus and mother (C{sub f}/C{sub m} ratio) were about 0.1 in each case. Concentrations in the yolk sac on day 12 were about 1% g{sup -1} compared with 0.01% g{sup -1} kin the foetus/ Retention in the guinea-pig foetus in late gestation at 7 days after administration (days 50-57) was about 0.2% injected activity per foetus, corresponding to a C{sub f}/C{sub m} = 0.2. Retention in each foetoplacental unit was 2% of injected {sup 106}Ru with 50% in the yolk sac, 35% in the placenta and 10% in the foetus. For administration 4 weeks prior to conception, the level of {sup 106}Ru retained in the foetus on day 57 of gestation was two orders of magnitude lower than after short-term administration, with a C{sub f}/C{sub m} about 0.004. (author).

  10. Proving the Efficiency of Placental Transfer of Maternal Measles ...

    African Journals Online (AJOL)

    [1] Small molecules. <600 Da are known to transit the human placenta to the fetus, while the passage of ... macromolecules in mother-infant pairs at birth in the University of Maiduguri .... the basis of these recommendations, protective titers for MMA ... newborn infants would start out with rather low MMA relative to that of their ...

  11. Preeclampsia, biomarkers, syncytiotrophoblast stress, and placental capacity.

    Science.gov (United States)

    Redman, Christopher W G; Staff, Anne Cathrine

    2015-10-01

    The maternal syndrome of preeclampsia is mediated by dysfunctional syncytiotrophoblast (STB). When this is stressed by uteroplacental malperfusion, its signaling to the mother changes, as part of a highly coordinated stress response. The STB signals are both proinflammatory and dysangiogenic such that the preeclamptic mother has a stronger vascular inflammatory response than normal, with an antiangiogenic bias. Angiogenic factors have limitations as preeclampsia biomarkers, especially for prediction and diagnosis of preeclampsia at term. However, if they are recognized as markers of STB stress, their physiological changes at term demonstrate that STB stress develops in all pregnancies. The biomarkers reveal that the duration of pregnancies is restricted by placental capacity, such that there is increasing placental dysfunction, at and beyond term. This capacity includes limitations imposed by the size of the uterus, the capacity of the uteroplacental circulation and, possibly, the supply of villous progenitor trophoblast cells. Limited placental capacity explains the increasing risks of postmaturity, including preeclampsia. Early-onset preeclampsia is predictable because STB stress and changes in its biomarkers are intrinsic to poor placentation, an early pregnancy pathology. Prediction of preeclampsia at term is not good because there is no early STB pathology. Moreover, biomarkers cannot accurately diagnose term preeclampsia against a background of universal STB dysfunction, which may or may not be clinically revealed before spontaneous or induced delivery. In this sense, postterm pregnancy is, at best, a pseudonormal state. However, the markers may prove useful in screening for women with more severe problems of postmaturity. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Placental lactogen levels in rhesus isoimmunization.

    Science.gov (United States)

    Ward, R H; Letchworth, A T; Niven, P A; Chard, T

    1974-03-02

    A prospective study of the plasma levels of human placental lactogen (HPL) in pregnancies complicated by rhesus isoimmunization showed that in mild and moderately affected cases the levels were normal, while in severely affected cases they were raised. Serial levels of HPL before the 26th week provide a valuable indication of fetal outcome, and we suggest that this estimation should be used routinely as an adjunct to other tests in the management of rhesus isoimmunization.

  13. Placentation in mammals once grouped as insectivores.

    Science.gov (United States)

    Carter, Anthony M; Enders, Allen C

    2010-01-01

    Interest in insectivoran grade mammals has been reawakened by taxonomic changes that place tenrecs and golden moles in a new order and separate hedgehogs from moles, shrews and solenodons. This survey of their placentation shows there is great variation even within families. As an example three subfamilies of tenrec have been examined. The interhemal region is cellular hemomonochorial in Echinops and Microgale but endotheliochorial in Micropotamogale. Golden moles, which are placed in the same order, have hemodichorial placentation. Many insectivores have complex arrangements for histotrophic nutrition involving columnar trophoblast cells. These range from areolae in moles through complexly folded hemophagous regions in tenrecs to the trophoblastic annulus in shrews. Of these placental characters, few offer support to current phylogenies. However, the case for placing hedgehogs and gymnures in a separate order (Erinaceomorpha) is bolstered by the presence of interstitial implantation, amniogenesis by cavitation, a hemochorial barrier and a prominent spongy zone; these features do not occur in shrews, moles or solenodons (Soricomorpha). Three insectivoran grade mammals deserve close attention as they have been selected for genome sequencing. One of these, the European hedgehog (Erinaceus europaeus), has not been studied with current methodology and renewed investigation of this or the closely related genus Atelerix should be a priority.

  14. PLACENTAL PATHOLOGY IN PREGNANCY INDUCED HYPERTENSION

    Directory of Open Access Journals (Sweden)

    Sreechithra

    2014-08-01

    Full Text Available BACKGROUND: Hypertensive disorders complicating pregnancy are common and form one of the deadly triad along with hemorrhage and infection, that results in a large number of maternal deaths and there of fetal deaths. Since all anabolites needed for foetal metabolism come from the mothers blood and foetal catabolites are passed back into the mothers circulation through the placenta, the examination of placenta gives a clear idea of what had happened with it, when it was in the mother, s womb and what is going to happen with the foetus in future. With this objective the present study was carried out. MATERIALS AND METHODS: Retrospective study was done for a period of 21 months from April1st 2008 to December 31st 2009..Fifty mothers with uncomplicated pregnancy (control group and 100 mothers (test group diagnosed as having pregnancy induced hypertension were selected from patients of our institution of the age range from 20-40 years, and parity –primi, para2 and 3.Placental morphometric parameters, gross and histopathological features were examined in both test and control groups. STATISTICAL ANALYSIS USED: Fishers exact test RESULTS: Placental morphometric parameters were significantly reduced in the control group. Acute atherosis, endothelial proliferation and fibrinoid necrosis were the significant histological findings noted in our study. CONCLUSION: Placental findings can be confirmatory of PIH, but its absence does not exclude the diseases. These findings will become more evident only when there is significant reduction in the uteroplacental bloodflow

  15. Preliminary interlaboratory comparison of the ex vivo dual human placental perfusion system

    DEFF Research Database (Denmark)

    Myllynen, Päivi; Mathiesen, Line; Weimer, Marc

    2010-01-01

    As a part of EU-project ReProTect, a comparison of the dual re-circulating human placental perfusion system was carried out, by two independent research groups. The detailed placental transfer data of model compounds [antipyrine, benzo(a)pyrene, PhIP (2-amino-1-methyl-6-phenylimidazo(4,5-b......)pyridine) and IQ (2-amino-3-methylimidazo(4,5-f)quinoline] has been/will be published separately. For this project, a comparative re-analysis was done, by curve fitting the data and calculating two endpoints: AUC(120), defined as the area under the curve between time 0 and time 120min and as t(0.5), defined...

  16. Placental dysfunction and fetal programming: the importance of placental size, shape, histopathology, and molecular composition.

    Science.gov (United States)

    Longtine, Mark S; Nelson, D Michael

    2011-05-01

    Normal function of the placenta is pivotal for optimal fetal growth and development. Fetal programming commonly is associated with placental dysfunction that predisposes to obstetric complications and suboptimal fetal outcomes. We consider several clinical phenotypes for placental dysfunction that likely predispose to fetal programming. Some of these reflect abnormal development of the chorioallantoic placenta in size, shape, or histopathology. Others result when exogenous stressors in the maternal environment combine with maladaptation of the placental response to yield small placentas with limited reserve, as typical of early-onset intrauterine growth restriction and preeclampsia. Still others reflect epigenetic changes, including altered expression of imprinted genes, altered enzymatic activity, or altered efficiencies in nutrient transport. Although the human placenta is a transient organ that persists only 9 months, the effects of this organ on the offspring remain for a lifetime.

  17. The placental mammal ancestor and the post-K-Pg radiation of placentals.

    Science.gov (United States)

    O'Leary, Maureen A; Bloch, Jonathan I; Flynn, John J; Gaudin, Timothy J; Giallombardo, Andres; Giannini, Norberto P; Goldberg, Suzann L; Kraatz, Brian P; Luo, Zhe-Xi; Meng, Jin; Ni, Xijun; Novacek, Michael J; Perini, Fernando A; Randall, Zachary S; Rougier, Guillermo W; Sargis, Eric J; Silcox, Mary T; Simmons, Nancy B; Spaulding, Michelle; Velazco, Paúl M; Weksler, Marcelo; Wible, John R; Cirranello, Andrea L

    2013-02-01

    To discover interordinal relationships of living and fossil placental mammals and the time of origin of placentals relative to the Cretaceous-Paleogene (K-Pg) boundary, we scored 4541 phenomic characters de novo for 86 fossil and living species. Combining these data with molecular sequences, we obtained a phylogenetic tree that, when calibrated with fossils, shows that crown clade Placentalia and placental orders originated after the K-Pg boundary. Many nodes discovered using molecular data are upheld, but phenomic signals overturn molecular signals to show Sundatheria (Dermoptera + Scandentia) as the sister taxon of Primates, a close link between Proboscidea (elephants) and Sirenia (sea cows), and the monophyly of echolocating Chiroptera (bats). Our tree suggests that Placentalia first split into Xenarthra and Epitheria; extinct New World species are the oldest members of Afrotheria.

  18. Placental Protein 13 (PP13 – a placental immunoregulatory galectin protecting pregnancy

    Directory of Open Access Journals (Sweden)

    Nandor Gabor Than

    2014-08-01

    Full Text Available Galectins are glycan-binding proteins that regulate innate and adaptive immune responses, and some confer maternal-fetal immune tolerance in eutherian mammals. A chromosome 19 cluster of galectins has emerged in anthropoid primates, species with deep placentation and long gestation. Three of the five human cluster galectins are solely expressed in the placenta, where they may confer additional immunoregulatory functions to enable deep placentation. One of these is galectin-13, also known as Placental Protein 13 (PP13. It has a jelly-roll fold, carbohydrate-recognition domain and sugar-binding preference resembling to other mammalian galectins. PP13 is predominantly expressed by the syncytiotrophoblast and released from the placenta into the maternal circulation. Its ability to induce apoptosis of activated T cells in vitro, and to divert and kill T cells as well as macrophages in the maternal decidua in situ suggests important immune functions. Indeed, mutations in the promoter and an exon of LGALS13 presumably leading to altered or non-functional protein expression are associated with a higher frequency of preeclampsia and other obstetrical syndromes, which involve immune dysregulation. Moreover, decreased placental expression of PP13 and its low first trimester maternal serum concentrations are associated with elevated risk of preeclampsia. Indeed, PP13 turned to be a good early biomarker to assess maternal risk for the subsequent development of pregnancy complications caused by impaired placentation. Due to the ischemic placental stress in preterm preeclampsia, there is an increased trophoblastic shedding of PP13 immunopositive microvesicles starting in the second trimester, which leads to high maternal blood PP13 concentrations. Our meta-analysis suggests that this phenomenon may enable the potential use of PP13 in directing patient management near to or at the time of delivery. Recent findings on the beneficial effects of PP13 on decreasing

  19. Elevated placental adenosine signaling contributes to the pathogenesis of preeclampsia.

    Science.gov (United States)

    Iriyama, Takayuki; Sun, Kaiqi; Parchim, Nicholas F; Li, Jessica; Zhao, Cheng; Song, Anren; Hart, Laura A; Blackwell, Sean C; Sibai, Baha M; Chan, Lee-Nien L; Chan, Teh-Sheng; Hicks, M John; Blackburn, Michael R; Kellems, Rodney E; Xia, Yang

    2015-02-24

    Preeclampsia is a prevalent hypertensive disorder of pregnancy and a leading cause of maternal and neonatal morbidity and mortality worldwide. This pathogenic condition is speculated to be caused by placental abnormalities that contribute to the maternal syndrome. However, the specific factors and signaling pathways that lead to impaired placentas and maternal disease development remain elusive. Using 2 independent animal models of preeclampsia (genetically engineered pregnant mice with elevated adenosine exclusively in placentas and a pathogenic autoantibody-induced preeclampsia mouse model), we demonstrated that chronically elevated placental adenosine was sufficient to induce hallmark features of preeclampsia, including hypertension, proteinuria, small fetuses, and impaired placental vasculature. Genetic and pharmacological approaches revealed that elevated placental adenosine coupled with excessive A₂B adenosine receptor (ADORA2B) signaling contributed to the development of these features of preeclampsia. Mechanistically, we provided both human and mouse evidence that elevated placental CD73 is a key enzyme causing increased placental adenosine, thereby contributing to preeclampsia. We determined that elevated placental adenosine signaling is a previously unrecognized pathogenic factor for preeclampsia. Moreover, our findings revealed the molecular basis underlying the elevation of placental adenosine and the detrimental role of excess placental adenosine in the pathophysiology of preeclampsia, and thereby, we highlight novel therapeutic targets. © 2014 American Heart Association, Inc.

  20. Placental localization by scanning with indium 113m

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Seung Wook; Choe, Yong Kyu; Choi, Byung Sook [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1972-09-15

    The application of radioactive tracers for placental localization has been introduced as the worthwhile diagnostic method in placenta previa. Recently {sup 113m}In has been applied as the broad spectrum agent for the visualization of various organs. The advantage of {sup 113m}In are a short half-life with 1.7 hours and no beta particle emission. During the period from May 1970 to August 1971, the placental scanning with {sup 113m}In was carried out at Yonsei Medical Center on 19 cases of Korean pregnant females who had painless vaginal bleeding with suspicious placenta previa or other placental lesions, clinically. Followings are the results of placental scanning with Indium-113m. 1) Eight cases out of 19 cases were suggested as placenta previa and the remaining 11 cases were turned out to be normal placental location. 2) Among these 8 case of positive scanning, placenta previa totalis was 6 cases, placental previa partialis was 1 case and placenta previa marginalis was also 1 case. 3) Among 11 cases of normal placental localization, right side placenta was 7 cases and left side, 4 cases. The placental scanning with Indium-113m is thought to be one of the simple, safe and rapid method with high accuracy for clinical diagnosis of the placenta previa and placental localization.

  1. Placental Abnormalities and Preeclampsia in Trisomy 13 Pregnancies

    Directory of Open Access Journals (Sweden)

    Chih-Ping Chen

    2009-03-01

    Full Text Available Women who are carrying a trisomy 13 fetus are prone to have an abnormal placenta as well as to develop preeclampsia in the second and third trimesters. This article provides a comprehensive review of placental abnormalities, such as small placental volume, reduced placental vascularization, a partial molar appearance of the placenta and placental mesenchymal dysplasia, and preeclampsia associated with trisomy 13 pregnancies. The candidate preeclampsia-causing genes on chromosome 13, such as sFlt1, COL4A2 and periostin, are discussed.

  2. Cesarean Delivery for a Life-threatening Preterm Placental Abruption

    Science.gov (United States)

    Okafor, II; Ugwu, EO

    2015-01-01

    Placental abruption is one of the major life-threatening obstetric conditions. The fetomaternal outcome of a severe placental abruption depends largely on prompt maternal resuscitation and delivery. A case of severe preterm placental abruption with intrauterine fetal death. Following a failed induction of labor with a deteriorating maternal condition despite resuscitation, emergency cesarean delivery was offered with good maternal outcome. Cesarean delivery could avert further disease progression and possible maternal death in cases of severe preterm placental abruption where vaginal delivery is not imminent. However, further studies are necessary before this could be recommended for routine clinical practice. PMID:27057388

  3. Clinical development of placental malaria vaccines and immunoassays harmonization

    DEFF Research Database (Denmark)

    Chêne, Arnaud; Houard, Sophie; Nielsen, Morten A;

    2016-01-01

    Placental malaria caused by Plasmodium falciparum infection constitutes a major health problem manifesting as severe disease and anaemia in the mother, impaired fetal development, low birth weight or spontaneous abortion. Prevention of placental malaria currently relies on two key strategies...... that are losing efficacy due to spread of resistance: long-lasting insecticide-treated nets and intermittent preventive treatment during pregnancy. A placental malaria vaccine would be an attractive, cost-effective complement to the existing control tools. Two placental malaria vaccine candidates are currently...

  4. Circulating placental proteins in pregnancies complicated by RH isoimmunization.

    Science.gov (United States)

    Lee, J N; Huang, S C; Ouyang, P C; Chard, T

    1984-07-01

    Nine pregnant women with Rh isoimmunization who delivered newborns with hydrops fetalis were studied. The placental proteins, pregnancy specific beta 1-glycoprotein (SP1), human placental lactogen, and placental protein 5 (PP5) were measured in maternal serum by radioimmunoassays. The results indicate that both the serum human placental lactogen and PP5 levels were significantly higher than those observed in normal pregnancy. The strikingly higher circulating PP5 levels found in all nine patients with Rh isoimmunization studied suggests that serum PP5 may be specifically elevated in pregnant patients with Rh isoimmunization and hydrops fetalis.

  5. Prevention of Defective Placentation and Pregnancy Loss by Blocking Innate Immune Pathways in a Syngeneic Model of Placental Insufficiency.

    Science.gov (United States)

    Gelber, Shari E; Brent, Elyssa; Redecha, Patricia; Perino, Giorgio; Tomlinson, Stephen; Davisson, Robin L; Salmon, Jane E

    2015-08-01

    Defective placentation and subsequent placental insufficiency lead to maternal and fetal adverse pregnancy outcome, but their pathologic mechanisms are unclear, and treatment remains elusive. The mildly hypertensive BPH/5 mouse recapitulates many features of human adverse pregnancy outcome, with pregnancies characterized by fetal loss, growth restriction, abnormal placental development, and defects in maternal decidual arteries. Using this model, we show that recruitment of neutrophils triggered by complement activation at the maternal/fetal interface leads to elevation in local TNF-α levels, reduction of the essential angiogenic factor vascular endothelial growth factor, and, ultimately, abnormal placentation and fetal death. Blockade of complement with inhibitors specifically targeted to sites of complement activation, depletion of neutrophils, or blockade of TNF-α improves spiral artery remodeling and rescues pregnancies. These data underscore the importance of innate immune system activation in the pathogenesis of placental insufficiency and identify novel methods for treatment of pregnancy loss mediated by abnormal placentation.

  6. Pomegranate juice and punicalagin attenuate oxidative stress and apoptosis in human placenta and in human placental trophoblasts.

    Science.gov (United States)

    Chen, Baosheng; Tuuli, Methodius G; Longtine, Mark S; Shin, Joong Sik; Lawrence, Russell; Inder, Terrie; Michael Nelson, D

    2012-05-15

    The human placenta is key to pregnancy outcome, and the elevated oxidative stress present in many complicated pregnancies contributes to placental dysfunction and suboptimal pregnancy outcomes. We tested the hypothesis that pomegranate juice, which is rich in polyphenolic antioxidants, limits placental trophoblast injury in vivo and in vitro. Pregnant women with singleton pregnancies were randomized at 35∼38 wk gestation to 8 oz/day of pomegranate juice or apple juice (placebo) until the time of delivery. Placental tissues from 12 patients (4 in the pomegranate group and 8 in the control group) were collected for analysis of oxidative stress. The preliminary in vivo results were extended to oxidative stress and cell death assays in vitro. Placental explants and cultured primary human trophoblasts were exposed to pomegranate juice or glucose (control) under defined oxygen tensions and chemical stimuli. We found decreased oxidative stress in term human placentas from women who labored after prenatal ingestion of pomegranate juice compared with apple juice as control. Moreover, pomegranate juice reduced in vitro oxidative stress, apoptosis, and global cell death in term villous explants and primary trophoblast cultures exposed to hypoxia, the hypoxia mimetic cobalt chloride, and the kinase inhibitor staurosporine. Punicalagin, but not ellagic acid, both prominent polyphenols in pomegranate juice, reduced oxidative stress and stimulus-induced apoptosis in cultured syncytiotrophoblasts. We conclude that pomegranate juice reduces placental oxidative stress in vivo and in vitro while limiting stimulus-induced death of human trophoblasts in culture. The polyphenol punicalagin mimics this protective effect. We speculate that antenatal intake of pomegranate may limit placental injury and thereby may confer protection to the exposed fetus.

  7. Chronic tempol prevents hypertension, proteinuria, and poor feto-placental outcomes in BPH/5 mouse model of preeclampsia.

    Science.gov (United States)

    Hoffmann, Darren S; Weydert, Christine J; Lazartigues, Eric; Kutschke, William J; Kienzle, Martha F; Leach, Jenny E; Sharma, Jennifer A; Sharma, Ram V; Davisson, Robin L

    2008-04-01

    Recently we described a mouse model, BPH/5, that spontaneously develops the hallmark clinical features of preeclampsia. BPH/5 exhibit impaired placentation before the onset of hypertension and proteinuria, supporting a causal role for the placenta in the pathogenesis of preeclampsia. Here we tested the hypothesis that an increase in reactive oxygen species (ROS) early in pregnancy results in placental abnormalities leading to the maternal symptoms of preeclampsia. We further hypothesized that chronic antioxidant therapy would ameliorate both feto-placental abnormalities and maternal symptoms. ROS levels measured by dihydroethidium revealed significant increases in oxidative stress in BPH/5 placentas at midgestation compared with C57 controls. This increase in ROS was correlated with reduced expression and activity of cytoplasmic superoxide dismutase in early and midgestation BPH/5 placentas. These abnormalities in placental oxidant factors occurred before the onset of maternal symptoms, suggesting a possible causal link between increased ROS and maternal and feto-placental pathology in this model. In support of this, chronic treatment of BPH/5 with the superoxide dismutase-mimetic Tempol throughout gestation significantly improved fetal growth and survival. Furthermore, Tempol ameliorated pregnancy-induced increases in blood pressure and proteinuria in BPH/5 mothers. We confirmed that Tempol radical was present in plasma, and it normalized ROS levels in all placental zones in BPH/5. These data for the first time demonstrate an important causative role for increased ROS in the placenta in the pathogenesis of preeclampsia in a model that spontaneously develops the disease. The results also strongly suggest the potential utility of antioxidant therapy in treating preeclampsia.

  8. Altered development and function of the placental regions in preeclampsia and its association with long-chain polyunsaturated fatty acids.

    Science.gov (United States)

    Rani, Alka; Wadhwani, Nisha; Chavan-Gautam, Preeti; Joshi, Sadhana

    2016-09-01

    The placenta is an essential organ formed during pregnancy that mainly transfers nutrients from the mother to the fetus. Nutrients taken up by the placenta are required for its own growth and development and to optimize fetal growth. Hence, placental function is an important determinant of pregnancy outcome. Among various nutrients, fatty acids, especially long-chain polyunsaturated fatty acids (LCPUFAs), including omega 3 and omega 6 fatty acids, are essential for placental development from the time of implantation. Studies have associated these LCPUFAs with placental development through their roles in regulating oxidative stress, angiogenesis, and inflammation, which may in turn influence their transfer to the fetus. The placenta has a heterogeneous morphology with variable regional vasculature, oxidative stress, and LCPUFA levels in healthy pregnancies depending upon the location within the placenta. However, these regional structural and functional parameters are found to be disturbed in pathological conditions, such as preeclampsia (PE), thereby affecting pregnancy outcome. Hence, the alterations in LCPUFA metabolism and transport in different regions of the PE placenta as compared with normal placenta could potentially be contributing to the pathological features of PE. The regional variations in development and function of the placenta and its possible association with placental LCPUFA metabolism and transport in normal and PE pregnancies are discussed in this review. WIREs Dev Biol 2016, 5:582-597. doi: 10.1002/wdev.238 For further resources related to this article, please visit the WIREs website.

  9. Water-Soluble Iron(IV)-Oxo Complexes Supported by Pentapyridine Ligands: Axial Ligand Effects on Hydrogen Atom and Oxygen Atom Transfer Reactivity.

    Science.gov (United States)

    Chantarojsiri, Teera; Sun, Yujie; Long, Jeffrey R; Chang, Christopher J

    2015-06-15

    We report the photochemical generation and study of a family of water-soluble iron(IV)-oxo complexes supported by pentapyridine PY5Me2-X ligands (PY5Me2 = 2,6-bis(1,1-bis(2-pyridyl)ethyl)pyridine; X = CF3, H, Me, or NMe2), in which the oxidative reactivity of these ferryl species correlates with the electronic properties of the axial pyridine ligand. Synthesis of a systematic series of [Fe(II)(L)(PY5Me2-X)](2+) complexes, where L = CH3CN or H2O, and characterizations by several methods, including X-ray crystallography, cyclic voltammetry, and Mössbauer spectroscopy, show that increasing the electron-donating ability of the axial pyridine ligand tracks with less positive Fe(III)/Fe(II) reduction potentials and quadrupole splitting parameters. The Fe(II) precursors are readily oxidized to their Fe(IV)-oxo counterparts using either chemical outer-sphere oxidants such as CAN (ceric ammonium nitrate) or flash-quench photochemical oxidation with [Ru(bpy)3](2+) as a photosensitizer and K2S2O8 as a quencher. The Fe(IV)-oxo complexes are capable of oxidizing the C-H bonds of alkane (4-ethylbenzenesulfonate) and alcohol (benzyl alcohol) substrates via hydrogen atom transfer (HAT) and an olefin (4-styrenesulfonate) substrate by oxygen atom transfer (OAT). The [Fe(IV)(O)(PY5Me2-X)](2+) derivatives with electron-poor axial ligands show faster rates of HAT and OAT compared to their counterparts supported by electron-rich axial donors, but the magnitudes of these differences are relatively modest.

  10. Prenatal endotoxemia and placental drug transport in the mouse: placental size-specific effects.

    Directory of Open Access Journals (Sweden)

    Enrrico Bloise

    Full Text Available Lipopolysaccharide (LPS in high doses inhibits placental multidrug resistance P-glycoprotein (P-gp--Abcb1a/b and breast cancer resistance protein (BCRP--Abcg2. This potentially impairs fetal protection against harmful factors in the maternal circulation. However, it is unknown whether LPS exposure, at doses that mimic sub-lethal clinical infection, alters placental multidrug resistance. We hypothesized that sub-lethal (fetal LPS exposure reduces placental P-gp activity. Acute LPS (n = 19;150 µg/kg; ip or vehicle (n = 19 were given to C57BL/6 mice at E15.5 and E17.5. Placentas and fetal-units were collected 4 and 24 h following injection. Chronic LPS (n = 6; 5 µg/kg/day; ip or vehicle (n = 5 were administered from E11.5-15.5 and tissues were collected 4 h after final treatment. P-gp activity was assessed by [³H]digoxin accumulation. Placental Abcb1a/b, Abcg2, interleukin-6 (Il-6, Tnf-α, Il-10 and toll-like receptor-4 (Tlr-4 mRNA were measured by qPCR. Maternal plasma IL-6 was determined. At E15.5, maternal IL-6 was elevated 4 h after single (p<0.001 and chronic (p<0.05 LPS, but levels had returned to baseline by 24 h. Placental Il-6 mRNA was also increased after acute and chronic LPS treatments (p<0.05, whereas Abcb1a/b and Abcg2 mRNA were unaffected. However, fetal [³H]digoxin accumulation was increased (p<0.05 4 h after acute LPS, and maternal [³H]digoxin myocardial accumulation was increased (p<0.05 in mice exposed to chronic LPS treatments. There was a negative correlation between fetal [³H]digoxin accumulation and placental size (p<0.0001. Acute and chronic sub-lethal LPS exposure resulted in a robust inflammatory response in the maternal systemic circulation and placenta. Acute infection decreased placental P-gp activity in a time- and gestational age-dependent manner. Chronic LPS decreased P-gp activity in the maternal myocardium and there was a trend for fetuses with smaller placentas to accumulate more P

  11. Placental glucose dehydrogenase polymorphism in Koreans.

    Science.gov (United States)

    Kim, Y J; Paik, S G; Park, H Y

    1994-12-01

    The genetic polymorphism of placental glucose dehydrogenase (GDH) was investigated in 300 Korean placentae using horizontal starch gel electrophoresis. The allele frequencies for GDH1, GDH2 and GDH3 were 0.537, 0.440 and 0.005, respectively, which were similar to those in Japanese. We also observed an anodal allele which was similar to the GDH4 originally reported in Chinese populations at a low frequency of 0.015. An additional new cathodal allele (named GDH6) was observed in the present study with a very low frequency of 0.003.

  12. Hans Strahl's pioneering studies in comparative placentation

    DEFF Research Database (Denmark)

    Carter, Anthony Michael; Mess, A

    2010-01-01

    and relationship to maternal tissues. This greatly influenced the work of Otto Grosser, who became better known in part because his work was more accessible to other scientists and clinicians. Strahl described the development of the fetal membranes across a broad range of mammalian orders extending his...... observations beyond parturition to the post partum involution of the uterus. He paid close attention to structures designed for histotrophic nutrition including the areolae of moles, haemophagous organs of carnivores and tenrecs and chorionic vesicles of lemurs and lorises. We here provide a summary of some...... of the most important findings made by Strahl including work on placentation in carnivores and higher primates that remains unsurpassed....

  13. Placentation in mammals once grouped as insectivores

    DEFF Research Database (Denmark)

    Carter, Anthony; Enders, Allen

    2009-01-01

    Interest in insectivoran grade mammals has been reawakened by taxonomic changes that place tenrecs and golden moles in a new order and separate hedgehogs from moles, shrews and solenodons. This survey of their placentation shows there is great variation even within families. As an example three...... in a separate order (Erinaceomorpha) is bolstered by the presence of interstitial implantation, amniogenesis by cavitation, a hemochorial barrier and a prominent spongy zone; these features do not occur in shrews, moles or solenodons (Soricomorpha). Three insectivoran grade mammals deserve close attention...

  14. Placental characteristics in women with polycystic ovary syndrome

    NARCIS (Netherlands)

    Koster, Maria P H; de Wilde, Marlieke A; Veltman-Verhulst, Susanne M; Houben, ML; Nikkels, Peter G J; van Rijn, Bas B; Fauser, Bart C J M

    2015-01-01

    STUDY QUESTION: Are macroscopic and microscopic placental characteristics in a heterogeneous group of women diagnosed with polycystic ovary syndrome (PCOS) different from those of a low-risk general population? SUMMARY ANSWER: Women with PCOS have significantly different microscopic placental charac

  15. Placental transport and in vitro effects of Bisphenol A

    DEFF Research Database (Denmark)

    Mørck, Thit J; Sorda, Giuseppina; Bechi, Nicoletta

    2010-01-01

    Bisphenol A (BPA), an estrogen-like chemical, leaches from consumer products potentially causing human exposure. To examine the effects of BPA exposure during pregnancy, we performed studies using the BeWo trophoblast cell line, placental explant cultures, placental perfusions and skin diffusion...

  16. Of mice and women: rodent models of placental malaria

    DEFF Research Database (Denmark)

    Hviid, Lars; Marinho, Claudio R F; Staalsoe, Trine

    2010-01-01

    Pregnant women are at increased malaria risk. The infections are characterized by placental accumulation of infected erythrocytes (IEs) with adverse consequences for mother and baby. Placental IE sequestration in the intervillous space is mediated by variant surface antigens (VSAs) selectively ex...

  17. Arrangement of collagen fibers in human placental stem villi

    NARCIS (Netherlands)

    Sati, Leyla; Demir, Ayse Yasemin; Sarikcioglu, Levent; Demir, Ramazan

    2008-01-01

    The aim of the study was to investigate the arrangements and related localization patterns of different collagen types in the stroma of placental stem villi by immunohistochemistry and electron microscopy. A total of 14 normal human term placental tissue samples were studied. Immunohistochemistry wa

  18. Arrangement of collagen fibers in human placental stem villi

    NARCIS (Netherlands)

    Sati, Leyla; Demir, Ayse Yasemin; Sarikcioglu, Levent; Demir, Ramazan

    2008-01-01

    The aim of the study was to investigate the arrangements and related localization patterns of different collagen types in the stroma of placental stem villi by immunohistochemistry and electron microscopy. A total of 14 normal human term placental tissue samples were studied. Immunohistochemistry

  19. Longitudinal study of serum placental GH in 455 normal pregnancies

    DEFF Research Database (Denmark)

    Chellakooty, Marla; Skibsted, Lillian; Skouby, Sven Olaf

    2002-01-01

    Placental GH is thought to be responsible for the rise in maternal IGF-I during pregnancy and is considered to be important for fetal growth. In this prospective longitudinal study of healthy pregnant women, we investigated determinants of placental GH in maternal serum. Serum was obtained from 4...

  20. Effects of soot absorption coefficient-Planck function correlation on radiative heat transfer in oxygen-enriched propane turbulent diffusion flame

    Science.gov (United States)

    Consalvi, J. L.; Nmira, F.

    2016-03-01

    The main objective of this article is to quantify the influence of the soot absorption coefficient-Planck function correlation on radiative loss and flame structure in an oxygen-enhanced propane turbulent diffusion flame. Calculations were run with and without accounting for this correlation by using a standard k-ε model and the steady laminar flamelet model (SLF) coupled to a joint Probability Density Function (PDF) of mixture fraction, enthalpy defect, scalar dissipation rate, and soot quantities. The PDF transport equation is solved by using a Stochastic Eulerian Field (SEF) method. The modeling of soot production is carried out by using a flamelet-based semi-empirical acetylene/benzene soot model. Radiative heat transfer is modeled by using a wide band correlated-k model and turbulent radiation interactions (TRI) are accounted for by using the Optically-Thin Fluctuation Approximation (OTFA). Predicted soot volume fraction, radiant wall heat flux distribution and radiant fraction are in good agreement with the available experimental data. Model results show that soot absorption coefficient and Planck function are negatively correlated in the region of intense soot emission. Neglecting this correlation is found to increase significantly the radiative loss leading to a substantial impact on flame structure in terms of mean and rms values of temperature. In addition mean and rms values of soot volume fraction are found to be less sensitive to the correlation than temperature since soot formation occurs mainly in a region where its influence is low.

  1. In vitro fertilization and embryo culture strongly impact the placental transcriptome in the mouse model.

    Directory of Open Access Journals (Sweden)

    Patricia Fauque

    Full Text Available BACKGROUND: Assisted Reproductive Technologies (ART are increasingly used in humans; however, their impact is now questioned. At blastocyst stage, the trophectoderm is directly in contact with an artificial medium environment, which can impact placental development. This study was designed to carry out an in-depth analysis of the placental transcriptome after ART in mice. METHODOLOGY/PRINCIPAL FINDINGS: Blastocysts were transferred either (1 after in vivo fertilization and development (control group or (2 after in vitro fertilization and embryo culture. Placentas were then analyzed at E10.5. Six percent of transcripts were altered at the two-fold threshold in placentas of manipulated embryos, 2/3 of transcripts being down-regulated. Strikingly, the X-chromosome harbors 11% of altered genes, 2/3 being induced. Imprinted genes were modified similarly to the X. Promoter composition analysis indicates that FOXA transcription factors may be involved in the transcriptional deregulations. CONCLUSIONS: For the first time, our study shows that in vitro fertilization associated with embryo culture strongly modify the placental expression profile, long after embryo manipulations, meaning that the stress of artificial environment is memorized after implantation. Expression of X and imprinted genes is also greatly modulated probably to adapt to adverse conditions. Our results highlight the importance of studying human placentas from ART.

  2. Use of magnetic resonance imaging in evaluation of placental invasion

    Energy Technology Data Exchange (ETDEWEB)

    Teo, T.H. [Department of Diagnostic Radiology, Singapore General Hospital (Singapore)], E-mail: thteo76@gmail.com; Law, Y.M.; Tay, K.H.; Tan, B.S.; Cheah, F.K. [Department of Diagnostic Radiology, Singapore General Hospital (Singapore)

    2009-05-15

    Aim: To review and describe the magnetic resonance imaging (MRI) features in patients with suspected placental invasion and correlate the findings with surgery and pathology findings. Materials and Methods: A retrospective review was undertaken of the MRI images of seven consecutive patients with ultrasound findings suspicious for placental invasion. Two experienced MRI radiologists, blinded to the pathology and surgery findings, reviewed the MRI. The pathology or surgical findings were used as the reference standard to establish accuracy and concordance with the MRI findings. Results: Three MRI features described in an earlier series were consistently present in the patients with placental invasion: lower uterine bulging, heterogeneous placenta, and dark intraplacental linear bands on T2-weighted images. Conclusion: MRI features, which were described in patients with placental invasion in an earlier series, were useful in establishing the presence and depth of placental invasion.

  3. Clinical development of placental malaria vaccines and immunoassays harmonization

    DEFF Research Database (Denmark)

    Chêne, Arnaud; Houard, Sophie; Nielsen, Morten A

    2016-01-01

    Placental malaria caused by Plasmodium falciparum infection constitutes a major health problem manifesting as severe disease and anaemia in the mother, impaired fetal development, low birth weight or spontaneous abortion. Prevention of placental malaria currently relies on two key strategies...... that are losing efficacy due to spread of resistance: long-lasting insecticide-treated nets and intermittent preventive treatment during pregnancy. A placental malaria vaccine would be an attractive, cost-effective complement to the existing control tools. Two placental malaria vaccine candidates are currently...... in Phase Ia/b clinical trials. During two workshops hosted by the European Vaccine Initiative, one in Paris in April 2014 and the other in Brussels in November 2014, the main actors in placental malaria vaccine research discussed the harmonization of clinical development plans and of the immunoassays...

  4. Multimodality imaging of placental masses: a pictorial review.

    Science.gov (United States)

    Jha, Priyanka; Paroder, Viktoriya; Mar, Winnie; Horowtiz, Jeanne M; Poder, Liina

    2016-12-01

    Placental masses are uncommonly identified at the time of obstetric ultrasound evaluation. Understanding the pathologies presenting as placental masses is key for providing a differential diagnosis and guiding subsequent management, which may include additional imaging with magnetic resonance (MR) imaging. Potential benign entities include chorioangiomas and teratomas. Larger chorioangiomas can cause fetal cardiovascular issues from volume overload. Placental mesenchymal dysplasia has an association with fetal anomalies and detailed fetal evaluation should be performed when it is suspected. Identifying other cystic masses such as partial and complete moles is crucial to prevent erroneous pregnancy termination. This review addresses normal imaging appearance of the placenta on ultrasound and MR imaging and describes various trophoblastic and nontrophoblastic placental masses. Potential placental mass mimics including uterine contractions and thrombo-hematomas are also presented.

  5. Placental Growth during Normal Pregnancy - A Magnetic Resonance Imaging Study

    DEFF Research Database (Denmark)

    Langhoff, Lasse; Grønbeck, Lene; von Huth, Sebastian

    2017-01-01

    was 640 g (range 500-787 g). All pregnancies were carried to term, resulting in the delivery of healthy infants with good correlation between placental size and birth weight (R = 0.56, p = 0.009). CONCLUSION: Placental growth was measured systematically in a longitudinal study through the second and third......OBJECTIVE: To investigate normal human placental growth longitudinally throughout the second and third trimesters using MRI. METHODS: Twenty normal, first-time singleton pregnancies were scanned 7 times between the 14th and 38th week of gestation, at 4-week intervals, using MRI. Placental volumes...... were measured in both sagittal and transversal slices. All placentas were weighed after delivery to make a comparative study. RESULTS: Sixteen of the 20 women had increasing placental volumes from the 14th to 38th week of gestation. The 6th and 7th scan showed that 4 women had placentas of the same...

  6. Determination of the Transport Rate of Xenobiotics and Nanomaterials Across the Placenta using the ex vivo Human Placental Perfusion Model

    Science.gov (United States)

    Grafmüller, Stefanie; Manser, Pius; Krug, Harald F.; Wick, Peter; von Mandach, Ursula

    2013-01-01

    Decades ago the human placenta was thought to be an impenetrable barrier between mother and unborn child. However, the discovery of thalidomide-induced birth defects and many later studies afterwards proved the opposite. Today several harmful xenobiotics like nicotine, heroin, methadone or drugs as well as environmental pollutants were described to overcome this barrier. With the growing use of nanotechnology, the placenta is likely to come into contact with novel nanoparticles either accidentally through exposure or intentionally in the case of potential nanomedical applications. Data from animal experiments cannot be extrapolated to humans because the placenta is the most species-specific mammalian organ 1. Therefore, the ex vivo dual recirculating human placental perfusion, developed by Panigel et al. in 1967 2 and continuously modified by Schneider et al. in 1972 3, can serve as an excellent model to study the transfer of xenobiotics or particles. Here, we focus on the ex vivo dual recirculating human placental perfusion protocol and its further development to acquire reproducible results. The placentae were obtained after informed consent of the mothers from uncomplicated term pregnancies undergoing caesarean delivery. The fetal and maternal vessels of an intact cotyledon were cannulated and perfused at least for five hours. As a model particle fluorescently labelled polystyrene particles with sizes of 80 and 500 nm in diameter were added to the maternal circuit. The 80 nm particles were able to cross the placental barrier and provide a perfect example for a substance which is transferred across the placenta to the fetus while the 500 nm particles were retained in the placental tissue or maternal circuit. The ex vivo human placental perfusion model is one of few models providing reliable information about the transport behavior of xenobiotics at an important tissue barrier which delivers predictive and clinical relevant data. PMID:23851364

  7. Determination of the transport rate of xenobiotics and nanomaterials across the placenta using the ex vivo human placental perfusion model.

    Science.gov (United States)

    Grafmüller, Stefanie; Manser, Pius; Krug, Harald F; Wick, Peter; von Mandach, Ursula

    2013-06-18

    Decades ago the human placenta was thought to be an impenetrable barrier between mother and unborn child. However, the discovery of thalidomide-induced birth defects and many later studies afterwards proved the opposite. Today several harmful xenobiotics like nicotine, heroin, methadone or drugs as well as environmental pollutants were described to overcome this barrier. With the growing use of nanotechnology, the placenta is likely to come into contact with novel nanoparticles either accidentally through exposure or intentionally in the case of potential nanomedical applications. Data from animal experiments cannot be extrapolated to humans because the placenta is the most species-specific mammalian organ (1). Therefore, the ex vivo dual recirculating human placental perfusion, developed by Panigel et al. in 1967 (2) and continuously modified by Schneider et al. in 1972 (3), can serve as an excellent model to study the transfer of xenobiotics or particles. Here, we focus on the ex vivo dual recirculating human placental perfusion protocol and its further development to acquire reproducible results. The placentae were obtained after informed consent of the mothers from uncomplicated term pregnancies undergoing caesarean delivery. The fetal and maternal vessels of an intact cotyledon were cannulated and perfused at least for five hours. As a model particle fluorescently labelled polystyrene particles with sizes of 80 and 500 nm in diameter were added to the maternal circuit. The 80 nm particles were able to cross the placental barrier and provide a perfect example for a substance which is transferred across the placenta to the fetus while the 500 nm particles were retained in the placental tissue or maternal circuit. The ex vivo human placental perfusion model is one of few models providing reliable information about the transport behavior of xenobiotics at an important tissue barrier which delivers predictive and clinical relevant data.

  8. Protein Profiling of Preeclampsia Placental Tissues

    Science.gov (United States)

    Shu, Chang; Liu, Zitao; Cui, Lifeng; Wei, Chengguo; Wang, Shuwen; Tang, Jian Jenny; Cui, Miao; Lian, Guodong; Li, Wei; Liu, Xiufen; Xu, Hongmei; Jiang, Jing; Lee, Peng; Zhang, David Y.

    2014-01-01

    Preeclampsia is a multi-system disorder involved in pregnancy without an effective treatment except delivery. The precise pathogenesis of this complicated disorder is still not completely understood. The objective of this study is to evaluate the alterations of protein expression and phosphorylations that are important in regulating placental cell function in preterm and term preeclampsia. Using the Protein Pathway Array, 38 proteins in placental tissues were found to be differentially expressed between preterm preeclampsia and gestational age matched control, while 25 proteins were found to be expressed differentially between term preeclampsia and matched controls. Among these proteins, 16 proteins and their associated signaling pathways overlapped between preterm and term preeclampsia, suggesting the common pathogenesis of two subsets of disease. On the other hand, many proteins are uniquely altered in either preterm or term preeclampsia and correlated with severity of clinical symptoms and outcomes, therefore, providing molecular basis for these two subsets of preeclampsia. Furthermore, the expression levels of some of these proteins correlated with neonatal small for gestational age (PAI-1 and PAPP-A) and adverse outcomes (Flt-1) in women with preterm preeclampsia. These proteins could potentially be used as candidate biomarkers for predicting outcomes of preeclampsia. PMID:25392996

  9. Confined placental mosaicisms and uniparental disomy

    Energy Technology Data Exchange (ETDEWEB)

    Kalousek, D.K.; Langlois, S.; Harrison, K.J. [Univ. of British Columbia, Vancouver (Canada)] [and others

    1994-09-01

    Approximately 2% of pregnancies studied with chorionic villous sampling (CVS) show confined placental mosaicism (CPM) which persists to term in 50-70% of cases. An increased frequency of complications, such as intrauterine fetal growth restriction or intrauterine death, is observed in these pregnancies. As trisomic zygote rescue is a common mechanism responsible for CPM, fetal uniparental disomy (UPD), resulting from the loss of the extra trisomic chromosome in the embryonic stem cells, would be expected to occur in a proportion of pregnancies with CPM. We have studied 27 pregnancies with CPM involving trisomies for chromosomes 2, 7, 9, 10, 12, and 16 for involvement of specific cell lineage(s) and levels of mosaicism in term placentas. Also, DNA from the parents and infant was analyzed for UPD or biparental disomy (BPD). Five infants with UPD for chromosome 16 and one infant with UPD for chromosome 7 were detected. All other infants showed BPD for the chromosome involved in CPM. For trisomy 16 mosaic gestations, a close correlation between high levels of trisomic cells in placenta and intrauterine fetal growth restriction has been found irrespective of the type of disomy present in the infant. The effect of other trisomies (2, 7, 9, 10, 12) on placental function appears to be similar, but the low numbers of pregnancies studied and lack of detection of UPD for chromosomes 2, 9, 10 and 12 does not allow a definitive conclusion.

  10. Protein profiling of preeclampsia placental tissues.

    Science.gov (United States)

    Shu, Chang; Liu, Zitao; Cui, Lifeng; Wei, Chengguo; Wang, Shuwen; Tang, Jian Jenny; Cui, Miao; Lian, Guodong; Li, Wei; Liu, Xiufen; Xu, Hongmei; Jiang, Jing; Lee, Peng; Zhang, David Y; He, Jin; Ye, Fei

    2014-01-01

    Preeclampsia is a multi-system disorder involved in pregnancy without an effective treatment except delivery. The precise pathogenesis of this complicated disorder is still not completely understood. The objective of this study is to evaluate the alterations of protein expression and phosphorylations that are important in regulating placental cell function in preterm and term preeclampsia. Using the Protein Pathway Array, 38 proteins in placental tissues were found to be differentially expressed between preterm preeclampsia and gestational age matched control, while 25 proteins were found to be expressed differentially between term preeclampsia and matched controls. Among these proteins, 16 proteins and their associated signaling pathways overlapped between preterm and term preeclampsia, suggesting the common pathogenesis of two subsets of disease. On the other hand, many proteins are uniquely altered in either preterm or term preeclampsia and correlated with severity of clinical symptoms and outcomes, therefore, providing molecular basis for these two subsets of preeclampsia. Furthermore, the expression levels of some of these proteins correlated with neonatal small for gestational age (PAI-1 and PAPP-A) and adverse outcomes (Flt-1) in women with preterm preeclampsia. These proteins could potentially be used as candidate biomarkers for predicting outcomes of preeclampsia.

  11. The Role of Placental Tryptophan Catabolism

    Science.gov (United States)

    Sedlmayr, Peter; Blaschitz, Astrid; Stocker, Roland

    2014-01-01

    This review discusses the mechanisms and consequences of degradation of tryptophan (Trp) in the placenta, focusing mainly on the role of indoleamine 2,3-dioxygenase-1 (IDO1), one of three enzymes catalyzing the first step of the kynurenine pathway of Trp degradation. IDO1 has been implicated in regulation of feto-maternal tolerance in the mouse. Local depletion of Trp and/or the presence of metabolites of the kynurenine pathway mediate immunoregulation and exert antimicrobial functions. In addition to the decidual glandular epithelium, IDO1 is localized in the vascular endothelium of the villous chorion and also in the endothelium of spiral arteries of the decidua. Possible consequences of IDO1-mediated catabolism of Trp in the endothelium encompass antimicrobial activity and immunosuppression, as well as relaxation of the placental vasotonus, thereby contributing to placental perfusion and growth of both placenta and fetus. It remains to be evaluated whether other enzymes mediating Trp oxidation, such as indoleamine 2,3-dioxygenase-2, Trp 2,3-dioxygenase, and Trp hydroxylase-1 are of relevance to the biology of the placenta. PMID:24904580

  12. Transport of nanoparticles through the placental barrier.

    Science.gov (United States)

    Kulvietis, Vytautas; Zalgeviciene, Violeta; Didziapetriene, Janina; Rotomskis, Ricardas

    2011-12-01

    Nanoparticles (NP) are organic or inorganic substances, the size of which ranges from 1 to 100 nm, and they possess specific properties which are different from those of the bulk materials in the macroscopic scale. In a recent decade, NP were widely applied in biomedicine as potential probes for imaging, drug-delivery systems and regenerative medicine. However, rapid development of nanotechnologies and their applications in clinical research have raised concerns about the adverse effects of NP on human health and environment. In the present review, special attention is paid to the fetal exposure to NP during the period of pregnancy. The ability to control the beneficial effects of NP and to avoid toxicity during treatment requires comprehensive knowledge about the distribution of NP in maternal body and possible penetration through the maternal-fetal barrier that might impair the embryogenesis. The initial in vivo and ex vivo studies imply that NP are able to cross the placental barrier, but the passage to the fetus depends on the size and the surface coating of NP as well as on the experimental model. The toxicity assays indicate that NP might induce adverse physiological effects and impede embryogenesis. The molecular transport mechanisms which are responsible for the transport of nanomaterials across the placental barrier are still poorly understood, and there is a high need for further studies in order to resolve the NP distribution patterns in the organism and to control the beneficial effects of NP applications during pregnancy without impeding the embryogenesis.

  13. Placental thrombomodulin expression in recurrent miscarriage

    Directory of Open Access Journals (Sweden)

    Turi Angelo

    2010-01-01

    Full Text Available Abstract Background Early pregnancy loss can be associated with trophoblast insufficiency and coagulation defects. Thrombomodulin is an endothelial-associated anticoagulant protein involved in the control of hemostasis and inflammation at the vascular beds and it's also a cofactor of the protein C anticoagulant pathway. Discussion We evaluate the Thrombomodulin expression in placental tissue from spontaneous recurrent miscarriage and voluntary abortion as controls. Thrombomodulin mRNA was determined using real-time quantitative polymerase chain reaction. Reduced expression levels of thrombomodulin were found in recurrent miscarriage group compared to controls (1.82-fold of reduction, that corresponds to a reduction of 45% (from control group Delta CT of thrombomodulin expression in spontaneous miscarriage group respect the control groups. Summary We cannot state at present the exact meaning of a reduced expression of Thrombomodulin in placental tissue. Further studies are needed to elucidate the biological pathway of this important factor in the physiopathology of the trophoblast and in reproductive biology.

  14. A Case of Placental Mesenchymal Dysplasia

    Directory of Open Access Journals (Sweden)

    Shigeki Taga

    2013-01-01

    Full Text Available Placental mesenchymal dysplasia (PMD rarely complicates with pregnancy. A 30-year-old woman, gravida 3, para 3, presenting with placentomegaly, was referred to our department at 18 weeks of gestation. An ultrasonography revealed a normal fetus with a large multicystic placenta, measuring 125 × 42 × 80 mm. The border between the lesion and normal region was not clear. Color doppler revealed little blood flow in the lesion. Magnetic resonance imaging revealed normal fetus and a large multicystic placenta. Serum human chorionic gonadotropin level was 20124.97 U/L, which was normal at 20 weeks of gestation. Thus, placental mesenchymal dysplasia rather than hydatidiform mole with coexistent fetus was suspected. Then, routine checkup was continued. Because she had the history of Cesarean section, an elective Cesarean section was performed at 37 weeks of gestation, and 2520 g female infant with apgar score 8/9 was delivered. The baby was normal with no evidence of Beckwith-Wiedemann syndrome. Placenta of 20 × 16 × 2 cm, weighing 720 g, was bulky with grape like vesicles involving whole placenta. Microscopic examination revealed dilated villi and vessels with thick wall which was lacking trophoblast proliferation. Large hydropic stem villi with myxomatous struma and cistern formation were seen. PMD was histopathologically confirmed.

  15. HSPC117 deficiency in cloned embryos causes placental abnormality and fetal death

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yingying [Department of Reproduction and Development, Kunming Institute of Zoology and Kunming Primate Research Center, Chinese Academy of Sciences, Kunming 650223 (China); State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Hai, Tang; Liu, Zichuan; Zhou, Shuya; Lv, Zhuo [State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Ding, Chenhui; Liu, Lei [State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080 (China); Niu, Yuyu [Department of Reproduction and Development, Kunming Institute of Zoology and Kunming Primate Research Center, Chinese Academy of Sciences, Kunming 650223 (China); Zhao, Xiaoyang; Tong, Man [State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Wang, Liu [State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080 (China); Jouneau, Alice [INRA, UMR 1198, ENVA, CNRS, FRE 2857, Biologie du Developpement et Reproduction, Jouy en Josas F-78350 (France); Zhang, Xun [Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114 (United States); Ji, Weizhi, E-mail: wji@mail.kiz.ac.cn [Department of Reproduction and Development, Kunming Institute of Zoology and Kunming Primate Research Center, Chinese Academy of Sciences, Kunming 650223 (China); Zhou, Qi, E-mail: qzhou@ioz.ac.cn [State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080 (China)

    2010-07-02

    Somatic cell nuclear transfer (SCNT) has been successfully used in many species to produce live cloned offspring, albeit with low efficiency. The low frequency of successful development has usually been ascribed to incomplete or inappropriate reprogramming of the transferred nuclear genome. Elucidating the genetic differences between normal fertilized and cloned embryos is key to understand the low efficiency of SCNT. Here, we show that expression of HSPC117, which encodes a hypothetical protein of unknown function, was absent or very low in cloned mouse blastocysts. To investigate the role of HSPC117 in embryo development, we knocked-down this gene in normal fertilized embryos using RNA interference. We assessed the post-implantation survival of HSPC117 knock-down embryos at 3 stages: E9 (prior to placenta formation); E12 (after the placenta was fully functional) and E19 (post-natal). Our results show that, although siRNA-treated in vivo fertilized/produced (IVP) embryos could develop to the blastocyst stage and implanted without any difference from control embryos, the knock-down embryos showed substantial fetal death, accompanied by placental blood clotting, at E12. Furthermore, comparison of HSPC117 expression in placentas of nuclear transfer (NT), intracytoplasmic sperm injection (ICSI) and IVP embryos confirmed that HSPC117 deficiency correlates well with failures in embryo development: all NT embryos with a fetus, as well as IVP and ICSI embryos, had normal placental HSPC117 expression while those NT embryos showing reduced or no expression of HSPC117 failed to form a fetus. In conclusion, we show that HSPC117 is an important gene for post-implantation development of embryos, and that HSPC117 deficiency leads to fetal abnormalities after implantation, especially following placental formation. We suggest that defects in HSPC117 expression may be an important contributing factor to loss of cloned NT embryos in vivo.

  16. Calibrating transition-metal energy levels and oxygen bands in first-principles calculations: Accurate prediction of redox potentials and charge transfer in lithium transition-metal oxides

    Science.gov (United States)

    Seo, Dong-Hwa; Urban, Alexander; Ceder, Gerbrand

    2015-09-01

    Transition-metal (TM) oxides play an increasingly important role in technology today, including applications such as catalysis, solar energy harvesting, and energy storage. In many of these applications, the details of their electronic structure near the Fermi level are critically important for their properties. We propose a first-principles-based computational methodology for the accurate prediction of oxygen charge transfer in TM oxides and lithium TM (Li-TM) oxides. To obtain accurate electronic structures, the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional is adopted, and the amount of exact Hartree-Fock exchange (mixing parameter) is adjusted to reproduce reference band gaps. We show that the HSE06 functional with optimal mixing parameter yields not only improved electronic densities of states, but also better energetics (Li-intercalation voltages) for LiCo O2 and LiNi O2 as compared to the generalized gradient approximation (GGA), Hubbard U corrected GGA (GGA +U ), and standard HSE06. We find that the optimal mixing parameters for TM oxides are system specific and correlate with the covalency (ionicity) of the TM species. The strong covalent (ionic) nature of TM-O bonding leads to lower (higher) optimal mixing parameters. We find that optimized HSE06 functionals predict stronger hybridization of the Co 3 d and O 2 p orbitals as compared to GGA, resulting in a greater contribution from oxygen states to charge compensation upon delithiation in LiCo O2 . We also find that the band gaps of Li-TM oxides increase linearly with the mixing parameter, enabling the straightforward determination of optimal mixing parameters based on GGA (α =0.0 ) and HSE06 (α =0.25 ) calculations. Our results also show that G0W0@GGA +U band gaps of TM oxides (M O ,M =Mn ,Co ,Ni ) and LiCo O2 agree well with experimental references, suggesting that G0W0 calculations can be used as a reference for the calibration of the mixing parameter in cases when no experimental band gap has been

  17. Waking the undead: Implications of a soft explosive model for the timing of placental mammal diversification.

    Science.gov (United States)

    Springer, Mark S; Emerling, Christopher A; Meredith, Robert W; Janečka, Jan E; Eizirik, Eduardo; Murphy, William J

    2017-01-01

    The explosive, long fuse, and short fuse models represent competing hypotheses for the timing of placental mammal diversification. Support for the explosive model, which posits both interordinal and intraordinal diversification after the KPg mass extinction, derives from morphological cladistic studies that place Cretaceous eutherians outside of crown Placentalia. By contrast, most molecular studies favor the long fuse model wherein interordinal cladogenesis occurred in the Cretaceous followed by intraordinal cladogenesis after the KPg boundary. Phillips (2016) proposed a soft explosive model that allows for the emergence of a few lineages (Xenarthra, Afrotheria, Euarchontoglires, Laurasiatheria) in the Cretaceous, but otherwise agrees with the explosive model in positing the majority of interordinal diversification after the KPg mass extinction. Phillips (2016) argues that rate transference errors associated with large body size and long lifespan have inflated previous estimates of interordinal divergence times, and further suggests that most interordinal divergences are positioned after the KPg boundary when rate transference errors are avoided through the elimination of calibrations in large-bodied and/or long lifespan clades. Here, we show that rate transference errors can also occur in the opposite direction and drag forward estimated divergence dates when calibrations in large-bodied/long lifespan clades are omitted. This dragging forward effect results in the occurrence of more than half a billion years of 'zombie lineages' on Phillips' preferred timetree. By contrast with ghost lineages, which are a logical byproduct of an incomplete fossil record, zombie lineages occur when estimated divergence dates are younger than the minimum age of the oldest crown fossils. We also present the results of new timetree analyses that address the rate transference problem highlighted by Phillips (2016) by deleting taxa that exceed thresholds for body size and lifespan

  18. Aerobic characteristics of red kangaroo skeletal muscles: is a high aerobic capacity matched by muscle mitochondrial and capillary morphology as in placental mammals?

    Science.gov (United States)

    Dawson, Terence J; Mifsud, Brock; Raad, Matthew C; Webster, Koa N

    2004-07-01

    Marsupials and placentals together comprise the Theria, the advanced mammals, but they have had long independent evolutionary histories, with the last common ancestor occurring more than 125 million years ago. Although in the past the marsupials were considered to be metabolically 'primitive', the red kangaroo Macropus rufus has been reported to have an aerobic capacity (VO2max) comparable to that of the most 'athletic' of placentals such as dogs. However, kangaroos travel at moderate speeds with lower relative cost than quadrupedal placentals. Given the long independent evolution of the two therian groups, and their unusual locomotor energetics, do kangaroos achieve their high aerobic capacity using the same structural and functional mechanisms used by (athletic) placentals? Red kangaroo skeletal muscle morphometry matched closely the general aerobic characteristics of placental mammals. The relationship between total mitochondrial volume in skeletal muscle and VO2max during exercise was identical to that in quadrupedal placentals, and differed from that in bipedal humans. As for placentals generally, red kangaroo mitochondrial oxygen consumption at VO2max was 4.7 ml O2 min(-1) ml(-1) of mitochondria. Also, the inner mitochondrial membrane densities were 35.8 +/- 0.7 m2 ml(-1) of mitochondria, which is the same as for placental mammals, and the same pattern of similarity was seen for capillary densities and volumes. The overall data for kangaroos was equivalent to that seen in athletic placentals such as dogs and pronghorns. Total skeletal muscle mass was high, being around 50% of body mass, and was concentrated around the pelvis and lower back. The majority of the muscles sampled had relatively high mitochondrial volume densities, in the range 8.8-10.6% in the major locomotor muscles. Again, capillary densities and capillary blood volumes followed the pattern seen for mitochondria. Our results indicate that the red kangaroo, despite its locomotion and extreme

  19. Electron transfer number control of the oxygen reduction reaction on nitrogen-doped reduced graphene oxides for the air electrodes of zinc-air batteries and organic degradation

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Sheng-Hui; Li, Po-Chieh; Hu, Chi-Chang, E-mail: cchu@che.nthu.edu.tw

    2016-11-01

    The mean electron transfer number (n) of the oxygen reduction reaction (ORR) on reduced graphene oxide (rGO) is controlled by nitrogen doping for the air electrodes of Zn-air batteries and electrochemical organic degradation. Melamine and pyrrole are employed as the nitrogen sources for fabricating N-doped rGO (N-rGO) by microwave-assisted hydrothermal synthesis (MAHS). The n value of the ORR is determined by the rotating ring-disk electrode (RRDE) voltammetry and is successfully controlled from 2.34 to 3.93 by preparation variables. The N-doped structures are examined by the x-ray photoelectron spectroscopic (XPS) analysis. The morphology and the defect degree of N-rGOs are characterized by high resolution transmission electron microscopy (HR-TEM) and Raman spectroscopy. N-rGOs with high and low n values are employed as the air electrode catalysts of zinc-air batteries and in-situ hydrogen peroxide (H{sub 2}O{sub 2}) generation, respectively. The highest discharge cell voltage of 1.235 V for a Zn-air battery is obtained at 2 mA cm{sup −2} meanwhile the current efficiency of H{sub 2}O{sub 2} generation in 1-h electrolysis at 0 V (vs. RHE) reaches 43%. The electrocatalytic degradation of orange G (OG), analyzed by UV-VIS absorption spectra, reveals a high decoloration degree from the relative absorbance of 0.38 for the azo π-conjugation structure of OG. - Highlights: • The mean electron transfer number (n) is controlled by nitrogen doping. • Melamine and pyrrole are used as the nitrogen sources for fabricating N-rGO. • The n value is successfully controlled from 2.34 to 3.93 by preparation variables. • The highest discharge cell voltage of 1.235 V for a Zn-air battery. • The current efficiency of H{sub 2}O{sub 2} generation 1-h electrolysis reaches 43%.

  20. IFPA meeting 2015 workshop report I: placental mitochondrial function, transport systems and epigenetics.

    Science.gov (United States)

    Bianco-Miotto, T; Blundell, C; Buckberry, S; Chamley, L; Chong, S; Cottrell, E; Dawson, P; Hanna, C; Holland, O; Lewis, R M; Moritz, K; Myatt, L; Perkins, A V; Powell, T; Saffery, R; Sferruzzi-Perri, A; Sibley, C; Simmons, D; O'Tierney-Ginn, P F

    2016-12-01

    Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialized topics. At IFPA meeting 2015 there were twelve themed workshops, three of which are summarized in this report. These workshops covered areas of placental regulation and nutrient handling: 1) placental epigenetics; 2) placental mitochondrial function; 3) placental transport systems.

  1. Associations between intrapartum death and piglet, placental, and umbilical characteristics.

    Science.gov (United States)

    Rootwelt, V; Reksen, O; Farstad, W; Framstad, T

    2012-12-01

    Intrapartum death in multiparous gestations in sows (Sus scrofa) is often caused by hypoxia. There is little information in the literature on the assessment of the placenta in relation to intrapartum death in piglets. The aim of this study was to evaluate the impact of the placental area and weight upon piglet birth characteristics and intrapartum death. Litters from 26 Landrace-Yorkshire sows were monitored during farrowing and the status of each piglet was recorded, including blood parameters of piglets and their umbilical veins. Of 413 piglets born, 6.5% were stillborn. Blood concentrations of glucose, lactate, and CO(2) partial pressure were increased in the stillborn piglets (P piglets, whereas pH and base excess were decreased (P piglets born dead vs. live (P piglets born dead was not different from live-born piglets (P = 0.631), whereas mean body mass index was reduced (P piglets were not different from live-born piglets (P = 0.662 and P = 0.253, respectively). Blood concentrations of lactate, hemoglobin, and hematocrit recorded in all piglets pooled were associated with placental area (P 0.2). Piglet BW was positively correlated with placental area and placental weight (P piglet birth weight, but not with the probability of being born dead. Placental area was a better predictor of piglet vitality than placental weight. Because umbilical cord rupture and prolonged birth time were associated with being born dead, umbilical cord rupture and placental detachment seem to be probable causes of intrapartum death.

  2. Nanostructured Ti(0.7)Mo(0.3)O2 support enhances electron transfer to Pt: high-performance catalyst for oxygen reduction reaction.

    Science.gov (United States)

    Ho, Van Thi Thanh; Pan, Chun-Jern; Rick, John; Su, Wei-Nien; Hwang, Bing-Joe

    2011-08-03

    The slow rate of the oxygen reduction reaction (ORR) and the instability of Pt-based catalysts are two of the most important issues that must be solved in order to make proton exchange membrane fuel cells (PEMFCs) a reality. Additionally, the serious carbon corrosion on the cathode side is a critical problem with respect to the durability of catalyst that limits its wide application. Here, we present a new approach by exploring robust noncarbon Ti(0.7)Mo(0.3)O(2) used as a novel functionalized cocatalytic support for Pt. This approach is based on the novel nanostructure Ti(0.7)Mo(0.3)O(2) support with "electronic transfer mechanism" from Ti(0.7)Mo(0.3)O(2) to Pt that can modify the surface electronic structure of Pt, owing to a shift in the d-band center of the surface Pt atoms. Furthermore, another benefit of Ti(0.7)Mo(0.3)O(2) is the extremely high stability of Pt/Ti(0.7)Mo(0.3)O(2) during potential cycling, which is attributable to the strong metal/support interaction (SMSI) between Pt and Ti(0.7)Mo(0.3)O(2). This also enhances the inherent structural and chemical stability and the corrosion resistance of the TiO(2)-based oxide in acidic and oxidative environments. We also demonstrate that the ORR current densities generated using cocatalytic Pt/Ti(0.7)Mo(0.3)O(2) are respectively ~7- and 2.6-fold higher than those of commercial Pt/C and PtCo/C catalysts with the same Pt loading. This new approach opens a reliable path to the discovery advanced concept in designing new catalysts that can replace the traditional catalytic structure and motivate further research in the field.

  3. Developmental programing: impact of testosterone on placental differentiation.

    Science.gov (United States)

    Beckett, E M; Astapova, O; Steckler, T L; Veiga-Lopez, A; Padmanabhan, V

    2014-08-01

    Gestational testosterone treatment causes maternal hyperinsulinemia, intrauterine growth retardation (IUGR), low birth weight, and adult reproductive and metabolic dysfunctions. Sheep models of IUGR demonstrate placental insufficiency as an underlying cause of IUGR. Placental compromise is probably the cause of fetal growth retardation in gestational testosterone-treated sheep. This study tested whether testosterone excess compromises placental differentiation by its androgenic action and/or via altered insulin sensitivity. A comparative approach of studying gestational testosterone (aromatizable androgen) against dihydrotestosterone (non-aromatizable androgen) or testosterone plus androgen antagonist, flutamide, was used to determine whether the effects of testosterone on placental differentiation were programed by its androgenic actions. Co-treatment of testosterone with the insulin sensitizer, rosiglitazone, was used to establish whether the effects of gestational testosterone on placentome differentiation involved compromised insulin sensitivity. Parallel cohorts of pregnant females were maintained for lambing and the birth weight of their offspring was recorded. Placental studies were conducted on days 65, 90, or 140 of gestation. Results indicated that i) gestational testosterone treatment advances placental differentiation, evident as early as day 65 of gestation, and culminates in low birth weight, ii) placental advancement is facilitated at least in part by androgenic actions of testosterone and is not a function of disrupted insulin homeostasis, and iii) placental advancement, while helping to increase placental efficiency, was insufficient to prevent IUGR and low-birth-weight female offspring. Findings from this study may be of relevance to women with polycystic ovary syndrome, whose reproductive and metabolic phenotype is captured by the gestational testosterone-treated offspring. © 2014 Society for Reproduction and Fertility.

  4. Risk of placental abruption in relation to migraines and headaches

    Directory of Open Access Journals (Sweden)

    Ananth Cande V

    2010-10-01

    Full Text Available Abstract Background Migraine, a common chronic-intermittent disorder of idiopathic origin characterized by severe debilitating headaches and autonomic nervous system dysfunction, and placental abruption, the premature separation of the placenta, share many common pathophysiological characteristics. Moreover, endothelial dysfunction, platelet activation, hypercoagulation, and inflammation are common to both disorders. We assessed risk of placental abruption in relation to maternal history of migraine before and during pregnancy in Peruvian women. Methods Cases were 375 women with pregnancies complicated by placental abruption, and controls were 368 women without an abruption. During in-person interviews conducted following delivery, women were asked if they had physician-diagnosed migraine, and they were asked questions that allowed headaches and migraine to be classified according to criteria established by the International Headache Society. Logistic regression procedures were used to calculate odds ratios (aOR and 95% confidence intervals (CI adjusted for confounders. Results Overall, a lifetime history of any headaches or migraine was associated with an increased odds of placental abruption (aOR = 1.60; 95% CI 1.16-2.20. A lifetime history of migraine was associated with a 2.14-fold increased odds of placental abruption (aOR = 2.14; 95% CI 1.22-3.75. The odds of placental abruption was 2.11 (95% CI 1.00-4.45 for migraineurs without aura; and 1.59 (95% 0.70-3.62 for migraineurs with aura. A lifetime history of tension-type headache was also increased with placental abruption (aOR = 1.61; 95% CI 1.01-2.57. Conclusions This study adds placental abruption to a growing list of pregnancy complications associated with maternal headache/migraine disorders. Nevertheless, prospective cohort studies are needed to more rigorously evaluate the extent to which migraines and/or its treatments are associated with the occurrence of placental abruption.

  5. Longitudinal study of serum placental GH in 455 normal pregnancies

    DEFF Research Database (Denmark)

    Chellakooty, Marla; Skibsted, Lillian; Skouby, Sven O

    2002-01-01

    women with normal singleton pregnancies at approximately 19 and 28 wk gestation. Serum placental GH concentrations were measured by a highly specific immunoradiometric assay, and fetal size was measured by ultrasound. Data on birth weight, gender, prepregnancy body mass index (BMI), parity, and smoking.......002). Placental GH at second examination was positively correlated with gestational age (P = 0.002) and negatively correlated with prepregnancy BMI (P = 0.039). Placental GH correlated with fetal weight at approximately 28 wk gestation (P = 0.002) but did not predict birth weight at term. Our study supports...

  6. [How to stimulate the placental function (author's transl)].

    Science.gov (United States)

    Fanard, A; Picazo, J J

    1976-01-01

    Imminent abortion, habitual abortion and threatened premature labor, all constitute difficult clinical problems. Those cases require on every occasion a diagnosis as acurate as possible, and unfortunately our present methods of biochemical determinations only represent a means to evaluate placental function. On those cases where a faulty placental function is detected thru the tests presently available, the authors recommend the utilization of a placentotropic substance, Gestanon, that is capable to stimulate and normalize the placental function, a is demostrated by the statistical results published in the international medical bibliography.

  7. Functional characterization of fetal and adult yak hemoglobins: an oxygen cascade and its molecular basis

    DEFF Research Database (Denmark)

    Weber, Roy E.; Braunitzer, Gerhard; Lalthantluanga, Ralte

    1988-01-01

    In contrast to most other mammals, the yak, which is native to high altitudes, has two major fetal and two or four major adult hemoglobin (Hb) components. We report the oxygen affinities and sensitivities to pH and 2,3-diphosphoglycerate of the two fetal and two adult Hbs commonly found in calves......, compared to those of adult cow Hb A, and relate these findings to their primary structures and to placental maternal-fetal oxygen transfer at altitude. Arranged in order of decreasing oxygen affinity the Hbs are F1 (alpha I2 gamma 2), F2 (alpha II2 gamma 2), A1 (alpha II2 beta II2), and cow Hb A....... The higher affinity of the fetal than the adult yak Hbs correlates with the beta 15Trp -->Phe substitution, whereas the higher affinity in yak than in cow Hb correlates with the beta 135Ala-->Val substitution. The difference in oxygen affinities between yak Hbs A1 and A2, which have identical beta chains...

  8. Placental lipases in pregnancies complicated by gestational diabetes mellitus (GDM.

    Directory of Open Access Journals (Sweden)

    Helen L Barrett

    Full Text Available Infants of women with gestational diabetes mellitus (GDM are more likely to be born large for gestational age with a higher percentage body fat. Elevated maternal lipids may contribute to this. Placental lipases such as lipoprotein lipase (LPL, endothelial lipase (EL and hormone sensitive lipase (HSL are involved in transferring lipids from mother to fetus. Previous studies of expression of these lipases in placentae in women with diabetes in pregnancy have reported divergent results. Intracellular lipases such as adipose triglyceride lipase (ATGL, and HSL are central to lipid droplet metabolism. The activities of these lipases are both influenced by Perilipin 1, and ATGL is also activated by a co-factor comparative gene identification-58 (CGI-58 and inhibited by G0/G1 switch gene 2 (GS02. None of these modifying factors or ATGL have been examined previously in placenta. The purpose of this study was therefore to examine the expression of ATGL, HSL, LPL, EL, as well as Perilipin 1, GS02 and CGI-58 in term pregnancies complicated by GDM. mRNA and protein expression of the lipases were measured in placentae from 17 women with GDM and 17 normoglycaemic pregnancies, matched for maternal BMI and gestational age of delivery. ATGL mRNA expression was increased and HSL mRNA expression reduced in placentae from GDM although there was no differences in protein expression of any of the lipases. All lipases were localised to trophoblasts and endothelial cells. The expression of Perilipin 1 and CGI-58 mRNA was increased and GS02 not altered in GDM. These results suggest that there is no difference in expression in these four lipases between GDM and normoglycaemic placentae, and therefore altered lipid transfer via these lipases does not contribute to large for gestational age in infants of women with GDM.

  9. Plasmodium vivax adherence to placental glycosaminoglycans.

    Directory of Open Access Journals (Sweden)

    Kesinee Chotivanich

    Full Text Available BACKGROUND: Plasmodium vivax infections seldom kill directly but do cause indirect mortality by reducing birth weight and causing abortion. Cytoadherence and sequestration in the microvasculature are central to the pathogenesis of severe Plasmodium falciparum malaria, but the contribution of cytoadherence to pathology in other human malarias is less clear. METHODOLOGY: The adherence properties of P. vivax infected red blood cells (PvIRBC were evaluated under static and flow conditions. PRINCIPAL FINDINGS: P. vivax isolates from 33 patients were studied. None adhered to immobilized CD36, ICAM-1, or thrombospondin, putative ligands for P. falciparum vascular cytoadherence, or umbilical vein endothelial cells, but all adhered to immobilized chondroitin sulphate A (CSA and hyaluronic acid (HA, the receptors for adhesion of P. falciparum in the placenta. PvIRBC also adhered to fresh placental cells (N = 5. Pre-incubation with chondroitinase prevented PvIRBC adherence to CSA, and reduced binding to HA, whereas preincubation with hyaluronidase prevented adherence to HA, but did not reduce binding to CSA significantly. Pre-incubation of PvIRBC with soluble CSA and HA reduced binding to the immobilized receptors and prevented placental binding. PvIRBC adhesion was prevented by pre-incubation with trypsin, inhibited by heparin, and reduced by EGTA. Under laminar flow conditions the mean (SD shear stress reducing maximum attachment by 50% was 0.06 (0.02 Pa but, having adhered, the PvIRBC could then resist detachment by stresses up to 5 Pa. At 37 °C adherence began approximately 16 hours after red cell invasion with maximal adherence at 30 hours. At 39 °C adherence began earlier and peaked at 24 hours. SIGNIFICANCE: Adherence of P. vivax-infected erythrocytes to glycosaminoglycans may contribute to the pathogenesis of vivax malaria and lead to intrauterine growth retardation.

  10. Placental insulin-like growth factor II (IGF-II) and its relation to litter size in the common marmoset monkey (Callithrix jacchus).

    Science.gov (United States)

    Rutherford, Julienne N; Eklund, Amy; Tardif, Suzette

    2009-12-01

    The primate placenta produces a wide variety of hormones throughout gestation that regulate placental function and fetal growth. One such hormone is insulin-like growth factor-II (IGF-II), a peptide implicated in cell division, differentiation, and amino acid transport. IGF-II concentrations were measured in 23 common marmoset (Callithrix jacchus) term placentas from twin and triplet litters in order to determine whether previously described differences in fetoplacental phenotype such as placental and litter mass and placental surface area were related to differences in endocrine function. IGF-II was extracted from frozen tissue samples and measured using an enzyme-linked immunosorbent assay kit designed for human tissue, which was validated for marmoset placenta. IGF-II concentrations were not related to placental or litter mass, and twin and triplet placentas did not differ in total concentration. However, per individual fetus, triplets were associated with a significant 42% reduction in IGF-II concentration (P = 0.03), and IGF-II concentration per gram of fetal mass was a third lower in triplet litters. The triplet placenta exhibits a global expansion of the surface area which was contrasted by a per unit area reduction in IGF-II concentration (r = -0.75, P = 0.01), a pattern that explains why twin and triplet placentas overall did not differ in concentration. Per fetus, triplet pregnancies are associated with relatively less maternal mass, placental mass and microscopic surface area suggesting that the intrauterine growth of triplets is supported by systems that increase the efficiency of nutrient transfer. The finding that individual triplet fetuses are also associated with significantly lower IGF-II concentrations is consistent with the view that the marmoset fetoplacental unit exhibits a flexible pattern of placental allocation and metabolism. Plasticity in placental endocrine and metabolic function is likely to play an important role in the ability of the

  11. Nitrogen transfers and air-sea N2O fluxes in the upwelling off Namibia within the oxygen minimum zone: a 3-D model approach

    Directory of Open Access Journals (Sweden)

    A. Paulmier

    2011-04-01

    Full Text Available As regions of high primary production and being often associated to Oxygen Minimum Zones (OMZs, Eastern Boundary Upwelling Systems (EBUS represent key regions for the oceanic nitrogen (N cycle. Indeed, by exporting the Organic Matter (OM and nutrients produced in the coastal region to the open ocean, EBUS can play an important role in sustaining primary production in subtropical gyres. Losses of fixed inorganic N, through denitrification and anammox processes and through nitrous oxide (N2O emissions to the atmosphere, take place in oxygen depleted environments such as EBUS, and alleviate the role of these regions as a source of N. In the present study, we developed a 3-D coupled physical/biogeochemical (ROMS/BioBUS model for investigating the full N budget in the Namibian sub-system of the Benguela Upwelling System (BUS. The different state variables of a climatological experiment have been compared to different data sets (satellite and in situ observations and show that the model is able to represent this biogeochemical oceanic region. The N transfer is investigated in the Namibian upwelling system using this coupled model, especially in the Walvis Bay area between 22° S and 24° S where the OMZ is well developed (O2 2 l−1. The upwelling process advects 24.2 × 1010 mol N yr−1 of nitrate enriched waters over the first 100 m over the slope and over the continental shelf. The meridional advection by the alongshore Benguela current brings also nutrient-rich waters with 21.1 × 1010 mol N yr−1. 10.5 × 1010 mol N yr−1 of OM are exported outside of the continental shelf (between 0 and 100-m depth. 32.4% and 18.1% of this OM are exported by advection in the form of Dissolved and Particulate Organic Matters (DOM and POM, respectively, however vertical sinking of POM represents the main contributor (49.5% to OM export outside of the first 100-m depth of the water column on the continental shelf. The continental slope also represents a net N

  12. Loss of Thrombomodulin in Placental Dysfunction in Preeclampsia

    NARCIS (Netherlands)

    Turner, Rosanne J; Bloemenkamp, Kitty W M; Bruijn, Jan A; Baelde, Hans J

    OBJECTIVE: Preeclampsia is a pregnancy-specific syndrome characterized by placental dysfunction and an angiogenic imbalance. Systemically, levels of thrombomodulin, an endothelium- and syncytiotrophoblast-bound protein that regulates coagulation, inflammation, apoptosis, and tissue remodeling, are

  13. Placental polyp: a rare cause of iron deficiency anemia

    Directory of Open Access Journals (Sweden)

    Fernando Peixoto Ferraz de Campos

    2011-12-01

    Full Text Available Placental polyps are defined as pedunculated or polypoid fragments of placentaor ovular membranes retained for an indefinite period of time into the uterus afterabortion or child birth. An important cause of retention is placental accretism, anabnormal adherence of the placenta into the uterine wall. Chronic cases are rarelyreported in the literature. In these cases, the placental retention in the immediatepostpartum is not followed by heavy bleeding what makes the diagnosischallenging. We report a rare case of iron-deficiency anemia in a multiparous29-year-old female patient two years after the last delivery. She sought medicalcare with clinical symptoms of anemia and recent menses alterations. Therewas no history of abortion. On gynecological examination, there was a twofoldenlarged uterus, and the pelvic ultrasound revealed an image compatible with anendometrial polyp. She underwent open hysterectomy because of uncontrollablebleeding followed by hypotension after curettage. The histolopathologicexamination revealed a partially hyalinized and necrotic placental polyp.

  14. Loss of Thrombomodulin in Placental Dysfunction in Preeclampsia

    NARCIS (Netherlands)

    Turner, Rosanne J; Bloemenkamp, Kitty W M; Bruijn, Jan A; Baelde, Hans J

    2016-01-01

    OBJECTIVE: Preeclampsia is a pregnancy-specific syndrome characterized by placental dysfunction and an angiogenic imbalance. Systemically, levels of thrombomodulin, an endothelium- and syncytiotrophoblast-bound protein that regulates coagulation, inflammation, apoptosis, and tissue remodeling, are i

  15. The effect of smoking on serum human placental lactogen levels.

    Science.gov (United States)

    Spellacy, W N; Buhi, W C; Birk, S A

    1977-02-01

    Serial serum samples (162) were drawn weekly from normal pregnant women (53) during the last month of gestation and measurements were made of the human placental lactogen (HPL) content. The women were interviewed as to their smoking habits and divided into nonsmokers (32) and smokers of from one to two packages of cigarettes per day (21). The infant birth weight and placental weights were not significantly different. The HPL levels were elevated in the women who smoked and the differences were significant at the thirty-sixth and thirty-eighth weeks. The importance of this in interpreting HPL as a placental function test and in terms of the biology of placental function and the control of protein hormone synthesis is emphasized.

  16. Placental loctogen levels associated with gross fetal abnormality.

    Science.gov (United States)

    Gau, G S; Cadle, G

    1977-02-01

    Four cases of severe congenital abnormality associated with persistently low maternal serum human placental lactogen levels are described. It is thought that this pattern might act as a warning of severe fetal abnormality.

  17. Comparative Placentation: Some Interesting Modifications for Histotrophic Nutrition - A Review

    DEFF Research Database (Denmark)

    Enders; Carter, Anthony M.

    2006-01-01

    In considering the diversity of Eutherian mammalian placental structure, it is helpful to keep in mind that both phylogenetically and ontogenetically a functional yolk sac placenta precedes development of the chorioallantoic placenta. Usually the chorioallantoic placenta progressively displaces t...

  18. Placental fetal vascular thrombosis lesions and maternal thrombophilia

    NARCIS (Netherlands)

    Beeksma, F. A.; Erwich, J. J. H. M.; Khong, T. Y.

    Aims: Following intrauterine fetal death (IUFD), the placental fetal vessels undergo regressive changes. These changes are virtually indistinguishable from lesions that are the result of fetal vascular thrombosis (FVT). This study investigated the relation between these lesions and maternal

  19. The new framework for understanding placental mammal evolution.

    Science.gov (United States)

    Asher, Robert J; Bennett, Nigel; Lehmann, Thomas

    2009-08-01

    An unprecedented level of confidence has recently crystallized around a new hypothesis of how living placental mammals share a pattern of common descent. The major groups are afrotheres (e.g., aardvarks, elephants), xenarthrans (e.g., anteaters, sloths), laurasiatheres (e.g., horses, shrews), and euarchontoglires (e.g., humans, rodents). Compared with previous hypotheses this tree is remarkably stable; however, some uncertainty persists about the location of the placental root, and (for example) the position of bats within laurasiatheres, of sea cows and aardvarks within afrotheres, and of dermopterans within euarchontoglires. A variety of names for sub-clades within the new placental mammal tree have been proposed, not all of which follow conventions regarding priority and stability. More importantly, the new phylogenetic framework enables the formulation of new hypotheses and testing thereof, for example regarding the possible developmental dichotomy that seems to distinguish members of the newly identified southern and northern radiations of living placental mammals.

  20. Maternal serum placental growth hormone, but not human placental lactogen or insulin growth factor-1, is positively associated with fetal growth in the first half of pregnancy

    DEFF Research Database (Denmark)

    Pedersen, N G; Juul, A; Christiansen, M

    2010-01-01

    To investigate if maternal levels of human placental lactogen (hPL), placental growth hormone (PGH) and insulin-like growth factor-1 (IGF-1) are associated with growth rate of the biparietal diameter (BPD) in the first half of pregnancy.......To investigate if maternal levels of human placental lactogen (hPL), placental growth hormone (PGH) and insulin-like growth factor-1 (IGF-1) are associated with growth rate of the biparietal diameter (BPD) in the first half of pregnancy....

  1. Maternal Prenatal Mental Health and Placental 11β-HSD2 Gene Expression: Initial Findings from the Mercy Pregnancy and Emotional Wellbeing Study

    Directory of Open Access Journals (Sweden)

    Sunaina Seth

    2015-11-01

    Full Text Available High intrauterine cortisol exposure can inhibit fetal growth and have programming effects for the child’s subsequent stress reactivity. Placental 11beta-hydroxysteroid dehydrogenase (11β-HSD2 limits the amount of maternal cortisol transferred to the fetus. However, the relationship between maternal psychopathology and 11β-HSD2 remains poorly defined. This study examined the effect of maternal depressive disorder, antidepressant use and symptoms of depression and anxiety in pregnancy on placental 11β-HSD2 gene (HSD11B2 expression. Drawing on data from the Mercy Pregnancy and Emotional Wellbeing Study, placental HSD11B2 expression was compared among 33 pregnant women, who were selected based on membership of three groups; depressed (untreated, taking antidepressants and controls. Furthermore, associations between placental HSD11B2 and scores on the State-Trait Anxiety Inventory (STAI and Edinburgh Postnatal Depression Scale (EPDS during 12–18 and 28–34 weeks gestation were examined. Findings revealed negative correlations between HSD11B2 and both the EPDS and STAI (r = −0.11 to −0.28, with associations being particularly prominent during late gestation. Depressed and antidepressant exposed groups also displayed markedly lower placental HSD11B2 expression levels than controls. These findings suggest that maternal depression and anxiety may impact on fetal programming by down-regulating HSD11B2, and antidepressant treatment alone is unlikely to protect against this effect.

  2. Oxygen Therapy

    Science.gov (United States)

    Oxygen therapy is a treatment that provides you with extra oxygen. Oxygen is a gas that your body needs to function. Normally, your lungs absorb oxygen from the air you breathe. But some conditions ...

  3. Placental Vascular Tree as Biomarker of Autism/ASD Risk

    Science.gov (United States)

    2013-09-01

    Carolyn M. Salafia, MD, MS, NYS Institute for Basic Research in Developmental Disabilities (IBR), 1050 Forest Hill Road, Staten Island, NY, 10314. Co...Carolyn M Salafia, MD, Institute for Basic Research (IBR), 1050 Forest Hill Road, Staten Island, NY, 10314. Co-Investigators: Michael Yampolsky, PhD...computer platforms; and Maplesoft Maple 9.0 Math & Engineering software. Placental histopathology diagnoses Placental disease was characterized by gross

  4. Multiscale modelling of the feto–placental vasculature

    Science.gov (United States)

    Clark, A. R.; Lin, M.; Tawhai, M.; Saghian, R.; James, J. L.

    2015-01-01

    The placenta provides all the nutrients required for the fetus through pregnancy. It develops dynamically, and, to avoid rejection of the fetus, there is no mixing of fetal and maternal blood; rather, the branched placental villi ‘bathe’ in blood supplied from the uterine arteries. Within the villi, the feto–placental vasculature also develops a complex branching structure in order to maximize exchange between the placental and maternal circulations. To understand the development of the placenta, we must translate functional information across spatial scales including the interaction between macro- and micro-scale haemodynamics and account for the effects of a dynamically and rapidly changing structure through the time course of pregnancy. Here, we present steps towards an anatomically based and multiscale approach to modelling the feto–placental circulation. We assess the effect of the location of cord insertion on feto–placental blood flow resistance and flow heterogeneity and show that, although cord insertion does not appear to directly influence feto–placental resistance, the heterogeneity of flow in the placenta is predicted to increase from a 19.4% coefficient of variation with central cord insertion to 23.3% when the cord is inserted 2 cm from the edge of the placenta. Model geometries with spheroidal and ellipsoidal shapes, but the same volume, showed no significant differences in flow resistance or heterogeneity, implying that normal asymmetry in shape does not affect placental efficiency. However, the size and number of small capillary vessels is predicted to have a large effect on feto–placental resistance and flow heterogeneity. Using this new model as an example, we highlight the importance of taking an integrated multi-disciplinary and multiscale approach to understand development of the placenta. PMID:25844150

  5. Multiscale modelling of the feto-placental vasculature.

    Science.gov (United States)

    Clark, A R; Lin, M; Tawhai, M; Saghian, R; James, J L

    2015-04-06

    The placenta provides all the nutrients required for the fetus through pregnancy. It develops dynamically, and, to avoid rejection of the fetus, there is no mixing of fetal and maternal blood; rather, the branched placental villi 'bathe' in blood supplied from the uterine arteries. Within the villi, the feto-placental vasculature also develops a complex branching structure in order to maximize exchange between the placental and maternal circulations. To understand the development of the placenta, we must translate functional information across spatial scales including the interaction between macro- and micro-scale haemodynamics and account for the effects of a dynamically and rapidly changing structure through the time course of pregnancy. Here, we present steps towards an anatomically based and multiscale approach to modelling the feto-placental circulation. We assess the effect of the location of cord insertion on feto-placental blood flow resistance and flow heterogeneity and show that, although cord insertion does not appear to directly influence feto-placental resistance, the heterogeneity of flow in the placenta is predicted to increase from a 19.4% coefficient of variation with central cord insertion to 23.3% when the cord is inserted 2 cm from the edge of the placenta. Model geometries with spheroidal and ellipsoidal shapes, but the same volume, showed no significant differences in flow resistance or heterogeneity, implying that normal asymmetry in shape does not affect placental efficiency. However, the size and number of small capillary vessels is predicted to have a large effect on feto-placental resistance and flow heterogeneity. Using this new model as an example, we highlight the importance of taking an integrated multi-disciplinary and multiscale approach to understand development of the placenta.

  6. [Fetal circulation in normal pregnancy and in placental insufficiency].

    Science.gov (United States)

    Ivanov, B; Malinova, M

    2010-01-01

    The fetal circulation is different from the adult circulation. One of the quite common conditions that are challenging to the developing fetus is placental hypoxia. Regardless of its cause, placental vascular insufficiency is commonly assumed to be an important factor in the development of intrauterine growth retardation. Several mechanisms are involved in the fetal adaptation to the decompensation during hypoxemia. Doppler Ultrasound technologies can help to evaluate of the fetal wellbeing.

  7. Organic Anion Transporter 4-Mediated Transport of Olmesartan at Basal Plasma Membrane of Human Placental Barrier.

    Science.gov (United States)

    Noguchi, Saki; Nishimura, Tomohiro; Fujibayashi, Ayasa; Maruyama, Tetsuo; Tomi, Masatoshi; Nakashima, Emi

    2015-09-01

    Mechanisms regulating fetal transfer of olmesartan, an angiotensin-II receptor type 1 antagonist, are important as potential determinants of life-threatening adverse fetal effects. The purpose of this study was to examine the olmesartan transport mechanism through the basal plasma membrane (BM) of human syncytiotrophoblasts forming the placental barrier. Uptake of olmesartan by human placental BM vesicles was potently inhibited by dehydroepiandrosterone sulfate (DHEAS), estrone 3-sulfate, and bromosulfophthalein, which are all typical substrates of organic anion transporter (OAT) 4 localized at the BM of syncytiotrophoblasts, and was increased in the absence of chloride. In tetracycline-inducible OAT4-expressing cells, [(3) H]olmesartan uptake was increased by tetracycline treatment. Olmesartan uptake via OAT4 was concentration dependent with a Km of 20 μM, and was increased in the absence of chloride. [(3) H]Olmesartan efflux via OAT4 was also observed and was trans-stimulated by extracellular chloride and DHEAS. Thus, OAT4 mediates bidirectional transport of olmesartan and appears to regulate fetal transfer of olmesartan at the BM of syncytiotrophoblasts. Efflux transport of olmesartan via OAT4 from syncytiotrophoblasts to the fetal circulation might be facilitated in the presence of an inwardly directed physiological chloride gradient and extracellular DHEAS. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  8. PLACENTAL LOCATION AT SECOND TRIMESTER AND PREGNANCY OUTCOMES

    Directory of Open Access Journals (Sweden)

    Seadati N

    2013-04-01

    Full Text Available The aimed of this study was to find association between location of placental at second trimester and pregnancy outcomes. It was a descriptive -analytic epidemiological study which has performed on 250 pregnant women by simple random sampling in Razi hospital and Imam Khomeini hospital during July 2011 – October 2012 in Ahvaz city, Iran. Placental location was determined by sonography at 18 - 22 weeks of gestation, and it was classified to high / low category and anterior / posterior category. In this study has been assessed placental location with incidence of preeclampsia, intrauterine growth restriction and preterm birth. The incidence of preeclampsia and intrauterine growth restriction was 5.6%, 1.6% respectively, these parameters were not associated with placental location (p=0.84, p=0.69. The incidence of preterm birth was 7.2% and it was associated with low placental location (p=0.01.There was no significant difference between anterior and posterior placenta in all of outcomes. Low placental location was associated with increased risk of preterm labor and preterm delivery.

  9. Metabolism of bupropion by baboon hepatic and placental microsomes.

    Science.gov (United States)

    Wang, Xiaoming; Abdelrahman, Doaa R; Fokina, Valentina M; Hankins, Gary D V; Ahmed, Mahmoud S; Nanovskaya, Tatiana N

    2011-08-01

    The aim of this investigation was to determine the biotransformation of bupropion by baboon hepatic and placental microsomes, identify the enzyme(s) catalyzing the reaction(s) and determine its kinetics. Bupropion was metabolized by baboon hepatic and placental microsomes to hydroxybupropion (OH-BUP), threo- (TB) and erythrohydrobupropion (EB). OH-bupropion was the major metabolite formed by hepatic microsomes (Km 36±6 μM, Vmax 258±32 pmol mg protein(-1) min(-1)), however the formation of OH-BUP by placental microsomes was below the limit of quantification. The apparent Km values of bupropion for the formation of TB and EB by hepatic and placental microsomes were similar. The selective inhibitors of CYP2B6 (ticlopidine and phencyclidine) and monoclonal antibodies raised against human CYP2B6 isozyme caused 80% inhibition of OH-BUP formation by baboon hepatic microsomes. The chemical inhibitors of aldo-keto reductases (flufenamic acid), carbonyl reductases (menadione), and 11β-hydroxysteroid dehydrogenases (18β-glycyrrhetinic acid) significantly decreased the formation of TB and EB by hepatic and placental microsomes. Data indicate that CYP2B of baboon hepatic microsomes is responsible for biotransformation of bupropion to OH-BUP, while hepatic and placental short chain dehydrogenases/reductases and to a lesser extent aldo-keto reductases are responsible for the reduction of bupropion to TB and EB.

  10. Progesterone and testosterone production by dispersed rat placental cells.

    Science.gov (United States)

    Matt, D W; Gibney, J A; Malamed, S; Macdonald, G J

    1986-04-01

    Isopycnic separation and unit gravity sedimentation were employed to identify the rat placental cell types capable of producing progesterone and testosterone. Subdivision of Day 12-dispersed placental cells in Percoll gradients revealed that fractions (less than 1.048 g/ml) containing giant cytotrophoblast cells produced greater quantities of progesterone (p less than 0.01) than did fractions (greater than 1.048 g/ml) with equal numbers of placental cells but void of giant cytotrophoblasts. Unit gravity sedimentation of Day 16-dispersed placental cells revealed that when incubated, isolated giant cytotrophoblast cells were capable of producing both progesterone and testosterone. Both of the separation studies strongly suggested that other cell types also produce steroids. However, the biosynthetic capacity of the giant cytotrophoblast cell appeared to be 1000-fold greater than that of the other cell types. Incubation of Day 12-dispersed placental cells with human chorionic gonadotropin or 3',5'-cyclic adenosine monophosphate did not further increase progesterone production as compared to untreated control incubates, suggesting rat placental steroidogenesis is not under trophic hormone control. Electron microscopic observations of giant cytotrophoblast cells revealed a complex ultrastructure suggesting a variety of physiological functions.

  11. Microvessel density in the placental bed among preeclampsia patients

    Directory of Open Access Journals (Sweden)

    Tarcisio Mota Coelho

    Full Text Available CONTEXT AND OBJECTIVE: Morphological changes in the spiral arteries of the placental bed have been studied in patients with preeclampsia, one of the largest causes of maternal and perinatal morbidity and mortality. The reports show that vasospasm and vascular endothelial injury were two major pathological conditions for preeclampsia. The aim of this study was to investigate the microvessel density of spiral arteries in the placental bed, in pregnancies complicated by hypertension and proteinuria, and in normal pregnancies. DESIGN AND SETTING: This was a cross-sectional survey of immunohistochemical studies on biopsies from the spiral arteries of the placental bed, among women undergoing cesarean sections for clinical and obstetrical reasons at Universidade Federal de São Paulo, São Paulo, Brazil. METHODS: Placental bed biopsies were obtained during cesarean section after placenta removal, with direct viewing of the central area of placenta insertion. The microvessel density of spiral arteries was measured by immunohistochemical methods in decidual and myometrial segments, using CD34 antibody. RESULTS: Biopsies containing spiral arteries were obtained from 34 hypertensive pregnant women with proteinuria, and 26 normotensive pregnant women. The microvessel densities in decidual and myometrial segments of the placental bed were compared between the groups. It was observed that, with increasing blood pressure and proteinuria, the microvessel density gradually decreased. CONCLUSION: The presence of high levels of hypertension and proteinuria may be associated with a progressive decrease in microvessel density in the placental bed.

  12. Transfer in vitro of three benzodiazepines across the human placenta.

    Science.gov (United States)

    Guerre-Millo, M; Rey, E; Challier, J C; Turquais, J M; d'Athis, P; Olive, G

    1979-04-17

    A comparative study of the placental transfer to the foetus of three benzodiazepines was performed using a dual perfusion system of the human placental lobule. A transport fraction was calculated for each benzodiazepine and was compared with reference substances. Relative to antipyrine, the transport fraction of diazepam was 85%, and that of nordiazepam was 84%. The transport fraction of clorazepate represented only 20% of that of tritiated water. The relatively high transfer of diazepam and nordiazepam can be attributed to their high lipid solubility, and the lower transfer of clorazepate is due to its polar nature. It is suggested that in certain instances this benzodiazepine may be of especial value to obstetricians.

  13. What do placental function tests predict? Observations on placental lactogen levels in growth retardation and fetal distress.

    Science.gov (United States)

    Obiekwe, B C; Chard, T

    1982-11-01

    Single blood samples were obtained from an unselected population of 527 women between 36 and 40 wk gestation. Serum placental lactogen levels were lower than normal in patients whose infants were growth retarded or developed fetal distress in labor. These associations were independent; the fetal distress group did not contain an excess of subjects with growth retardation. Thus, the results of a biochemical test reflect dynamic aspects of placental function and not simply the overall growth of fetus and placenta.

  14. Placentation in the colugos Cynocephalus volans and Galeopterus variegatus (Dermoptera) and the transition from labyrinthine to villous placentation in primates

    DEFF Research Database (Denmark)

    Carter, A. M.; Mess, A. M.

    2017-01-01

    Introduction Phylogenetics and genomics place colugos as the sister group to primates. Therefore their placentation is of interest in an evolutionary perspective. Previous accounts are fragmentary, not readily accessible and sometimes contradictory. Methods We have examined archival material...... covering the early development of fetal membranes and placenta, the fate of the yolk sac and definitive placentation. Results Initially the trophoblast extended over a rather broad but shallow area, enclosing maternal blood spaces. After expansion of the exocoelom it became covered by somatic mesoderm...

  15. Transfer of maternal psychosocial stress to the fetus.

    Science.gov (United States)

    Rakers, Florian; Rupprecht, Sven; Dreiling, Michelle; Bergmeier, Christoph; Witte, Otto W; Schwab, Matthias

    2017-02-22

    Psychosocial maternal stress experienced during different vulnerable periods throughout gestation is thought to increase the individual's risk to develop neuropsychiatric, cardiovascular and metabolic disease in later life. Cortisol has generally been identified as the major mediator of maternal stress transfer to the fetus. Its lipophilic nature allows a trans-placental passage and thus excessive maternal cortisol could persistently impair the development of the fetal hypothalamic-pituitary-adrenal axis (HPAA). However, cortisol alone cannot fully explain all effects of maternal stress especially during early to mid pregnancy before maturation of the fetal HPAA has even begun and expression of fetal glucocorticoid receptors is limited. This review focuses on mediators of maternal fetal stress transfer that in addition to cortisol have been proposed as transmitters of maternal stress: catecholamines, cytokines, serotonin/tryptophan, reactive-oxygen-species and the maternal microbiota. We propose that the effects of psychosocial maternal stress on fetal development and health and disease in later life are not a consequence of a single pathway but are mediated by multiple stress-transfer mechanisms acting together in a synergistic manner.

  16. Toward a Full Simulation of the Basic Oxygen Furnace: Deformation of the Bath Free Surface and Coupled Transfer Processes Associated with the Post-Combustion in the Gas Region

    Science.gov (United States)

    Doh, Y.; Chapelle, P.; Jardy, A.; Djambazov, G.; Pericleous, K.; Ghazal, G.; Gardin, P.

    2013-06-01

    The present article treats different phenomena taking place in a steelmaking converter through the development of two separate models. The first model describes the cavity produced at the free surface of the metal bath by the high-speed impinging oxygen jet. The model is based on a zonal approach, where gas compressibility effects are taken into account only in the high velocity jet region, while elsewhere the gas is treated as incompressible. The volume of fluid (VOF) method is employed to follow the deformation of the bath free surface. Calculations are presented for two- and three-phase systems and compared against experimental data obtained in a cold model experiment presented in the literature. The influence on the size and shape of the cavity of various parameters and models (including the jet inlet boundary conditions, the VOF advection scheme, and the turbulence model) is studied. Next, the model is used to simulate the interaction of a supersonic oxygen jet with the surface of a liquid steel bath in a pilot-scale converter. The second model concentrates on fluid flow, heat transfer, and the post-combustion reaction in the gas phase above the metal bath. The model uses the simple chemical reaction scheme approach to describe the transport of the chemical species and takes into account the consumption of oxygen by the bath and thermal radiative transfer. The model predictions are in reasonable agreement with measurements collected in a laboratory experiment and in a pilot-scale furnace.

  17. Evolutionary perspectives into placental biology and disease

    Directory of Open Access Journals (Sweden)

    Edward B. Chuong

    2013-12-01

    Full Text Available In all mammals including humans, development takes place within the protective environment of the maternal womb. Throughout gestation, nutrients and waste products are continuously exchanged between mother and fetus through the placenta. Despite the clear importance of the placenta to successful pregnancy and the health of both mother and offspring, relatively little is understood about the biology of the placenta and its role in pregnancy-related diseases. Given that pre- and peri-natal diseases involving the placenta affect millions of women and their newborns worldwide, there is an urgent need to understand placenta biology and development. Here, we suggest that the placenta is an organ under unique selective pressures that have driven its rapid diversification throughout mammalian evolution. The high divergence of the placenta complicates the use of non-human animal models and necessitates an evolutionary perspective when studying its biology and role in disease. We suggest that diversifying evolution of the placenta is primarily driven by intraspecies evolutionary conflict between mother and fetus, and that many pregnancy diseases are a consequence of this evolutionary force. Understanding how maternal–fetal conflict shapes both basic placental and reproductive biology – in all species – will provide key insights into diseases of pregnancy.

  18. Human placental lactogen levels in multiple pregnancies.

    Science.gov (United States)

    Spellacy, W N; Buhi, W C; Birk, S A

    1978-08-01

    Serum human placental lactogen (hPL) levels were measured in duplicate with a radioimmunoassay in 206 serum samples at 30 and 36 weeks' gestation from women with normal singleton pregnancies (75) or pregnancies with twins (37). One triplet pregnancy was also studied. The results show a significant elevation of hPL in the women with twin pregnancies at both the 30th (7.0 vs 6.0 microgram/ml) and the 36th (9.2 vs 7.4 microgram/ml) weeks. One-third of the twin pregnancies had values of hPL in excess of 8.0 microgram/ml at 30 weeks and more than half had values in excess of 9.0 microgram/ml at 36 weeks. The triplet pregnancy had an hPL value of 11.0 microgram/ml at 36 weeks' gestation. These data support the potential usefulness of serum hPL measurements in the screening profile for the detection of high-risk pregnancies.

  19. Placental Cadmium Levels Are Associated with Increased Preeclampsia Risk.

    Science.gov (United States)

    Laine, Jessica E; Ray, Paul; Bodnar, Wanda; Cable, Peter H; Boggess, Kim; Offenbacher, Steven; Fry, Rebecca C

    2015-01-01

    Environmental exposure to heavy metals is a potentially modifiable risk factor for preeclampsia (PE). Toxicologically, there are known interactions between the toxic metal cadmium (Cd) and essential metals such as selenium (Se) and zinc (Zn), as these metals can protect against the toxicity of Cd. As they relate to preeclampsia, the interaction between Cd and these essential metals is unknown. The aims of the present study were to measure placental levels of Cd, Se, and Zn in a cohort of 172 pregnant women from across the southeast US and to examine associations of metals levels with the odds of PE in a nested case-control design. Logistic regressions were performed to assess odds ratios (OR) for PE with exposure to Cd controlling for confounders, as well as interactive models with Se or Zn. The mean placental Cd level was 3.6 ng/g, ranging from 0.52 to 14.5 ng/g. There was an increased odds ratio for PE in relationship to placental levels of Cd (OR = 1.5; 95% CI: 1.1-2.2). The Cd-associated OR for PE increased when analyzed in relationship to lower placental Se levels (OR = 2.0; 95% CI: 1.1-3.5) and decreased with higher placental Se levels (OR = 0.98; 95% CI: 0.5-1.9). Similarly, under conditions of lower placental Zn, the Cd-associated OR for PE was elevated (OR = 1.8; 95% CI: 0.8-3.9), whereas with higher placental Zn it was reduced (OR = 1.3; 95% CI: 0.8-2.0). Data from this pilot study suggest that essential metals may play an important role in reducing the odds of Cd-associated preeclampsia and that replication in a larger cohort is warranted.

  20. [The role of oxidative stress in placental-related diseases of pregnancy].

    Science.gov (United States)

    Jauniaux, E; Burton, G J

    2016-10-01

    In normal pregnancies, the earliest stages of development take place in a low oxygen (O2) environment. This physiological hypoxia of the early gestational sac protects the developing fetus against the deleterious and teratogenic effects of O2free radicals. Oxidative stress is manifested at the maternal-fetal interface from early pregnancy onwards. In early pregnancy, a well-controlled oxidative stress plays a role in modulating placental development, functions and remodelling. Focal trophoblastic oxidative damage and progressive villous degeneration trigger the formation of the fetal membranes, which is an essential developmental step enabling vaginal delivery. Our data have demonstrated that the first trimester placenta in humans is histiotrophic and not haemochorial. The development and maintenance of a physiological O2 gradient between the uterine and fetal circulations is also essential for placental functions, such as transport and hormonal synthesis. Pathological oxidative stress arises when the production of reactive O2 species overwhelms the intrinsic anti-oxidant defences causing indiscriminate damage to biological molecules, leading to loss of function and cell death. We here review the role of oxidative stress in the pathophysiology of miscarriage, pre-eclampsia and fetal growth restriction. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  1. Maternal risk factors for abnormal placental growth: The national collaborative perinatal project

    Directory of Open Access Journals (Sweden)

    Nicholson Wanda K

    2008-09-01

    Full Text Available Abstract Background Previous studies of maternal risk factors for abnormal placental growth have focused on placental weight and placental ratio as measures of placental growth. We sought to identify maternal risk factors for placental weight and two neglected dimensions of placental growth: placental thickness and chorionic plate area. Methods We conducted an analysis of 24,135 mother-placenta pairs enrolled in the National Collaborative Perinatal Project, a prospective cohort study of pregnancy and child health. We defined growth restriction as th percentile and hypertrophy as > 90th percentile for three placental growth dimensions: placental weight, placental thickness and chorionic plate area. We constructed parallel multinomial logistic regression analyses to identify (a predictors of restricted growth (vs. normal and (b predictors of hypertrophic growth (vs. normal. Results Black race was associated with an increased likelihood of growth restriction for placental weight, thickness and chorionic plate area, but was associated with a reduced likelihood of hypertrophy for these three placental growth dimensions. We observed an increased likelihood of growth restriction for placental weight and chorionic plate area among mothers with hypertensive disease at 24 weeks or beyond. Anemia was associated with a reduced likelihood of growth restriction for placental weight and chorionic plate area. Pre-pregnancy BMI and pregnancy weight gain were associated with a reduced likelihood of growth restriction and an increased likelihood of hypertrophy for all three dimensions of placental growth. Conclusion Maternal risk factors are either associated with placental growth restriction or placental hypertrophy not both. Our findings suggest that the placenta may have compensatory responses to certain maternal risk factors suggesting different underlying biological mechanisms.

  2. Bioactive factors in uteroplacental and systemic circulation link placental ischemia to generalized vascular dysfunction in hypertensive pregnancy and preeclampsia.

    Science.gov (United States)

    Shah, Dania A; Khalil, Raouf A

    2015-06-15

    Preeclampsia is a pregnancy-associated disorder characterized by hypertension, and could lead to maternal and fetal morbidity and mortality; however, the pathophysiological mechanisms involved are unclear. Predisposing demographic, genetic and environmental risk factors could cause localized abnormalities in uteroplacental cytoactive factors such as integrins, matrix metalloproteinases, cytokines and major histocompatibility complex molecules leading to decreased vascular remodeling, uteroplacental vasoconstriction, trophoblast cells apoptosis, and abnormal development of the placenta. Defective placentation and decreased trophoblast invasion of the myometrium cause reduction in uteroplacental perfusion pressure (RUPP) and placental ischemia/hypoxia, an important event in preeclampsia. RUPP could stimulate the release of circulating bioactive factors such as the anti-angiogenic factors soluble fms-like tyrosine kinase-1 and soluble endoglin that cause imbalance with the pro-angiogenic factors vascular endothelial growth factor and placental growth factor, or cause the release of inflammatory cytokines, reactive oxygen species, hypoxia-induced factor-1 and AT1 angiotensin receptor agonistic autoantibodies. The circulating bioactive factors target endothelial cells causing generalized endotheliosis, endothelial dysfunction, decreased vasodilators such as nitric oxide and prostacyclin and increased vasoconstrictors such as endothelin-1 and thromboxane A2, leading to increased vasoconstriction. The bioactive factors also stimulate the mechanisms of VSM contraction including Ca(2+), protein kinase C, and Rho-kinase and induce extracellular matrix remodeling leading to further vasoconstriction and hypertension. While therapeutic options are currently limited, understanding the underlying mechanisms could help design new interventions for management of preeclampsia.

  3. Histopathological placental lesions in mild gestational hyperglycemic and diabetic women

    Directory of Open Access Journals (Sweden)

    Rudge Marilza VC

    2011-08-01

    Full Text Available Abstract Objective To investigate and compare the incidence of histopathological placental lesions in mild gestational hyperglycemia, gestational diabetes and overt diabetes at term and preterm gestation. Research design and methods One-hundred-and-thirty-one placental samples were collected from Diabetes mellitus (DM positive screened patients. Two diagnostic tests, glycemic profile and 100 g oral glucose tolerance test (OGTT in parallel identified 4 groups normoglycemic, mild gestational hyperglycemia (MGH, gestational DM (GDM or overt DM (DM. Placental tissue specimens and sections from 4 groups were obtained by uniform random sampling and stained with hematoxylin-eosin. Results Placentas from MGH group presented 17 types of histopathological change and higher rates of syncytial nodes and endarteritis. GDM placentas presented only nine types of histopathological change, high rates of dysmaturity, low rates of calcification and no syncytial nodes. Overt DM placentas showed 22 types of histopathological change, 21 of which were present in the preterm period. There were histopathological similarities between MGH and DM placentas, but the former exhibited a higher incidence of endarteritis, which has been described as a "post-mortem" phenomenon. Conclusion Our results confirmed that the distinct placental changes associated with DM and MGH depend on gestational period during which the diabetic insult occurs. It may reasonably be inferred that subclinical maternal hyperglycemia during pregnancy, as showed in MGH group, is responsible for increased placental endarteritis, a postmortem lesion in the live fetus.

  4. Adenylate kinase locus 1 polymorphism and feto-placental development.

    Science.gov (United States)

    Fulvia, Gloria-Bottini; Antonio, Pietroiusti; Anna, Neri; Patrizia, Saccucci; Ada, Amante; Egidio, Bottini; Andrea, Magrini

    2011-12-01

    Recently our group has found that the correlation between birth weight and placental weight - an index of a balanced feto-placental unit development - is influenced by genetic factors. Since adenylate kinase locus 1 (AK₁) is a polymorphic enzyme that plays an important role in the synthesis of nucleotides required for many metabolic functions, we have investigated the possible role of its genetic variability in the correlation between birth weight and placental weight. 342 consecutive healthy newborn infants from the population of Rome (Italy) and 286 puerperae from another population from Central Italy were studied. The correlation coefficient between birth weight and placental weight is much higher in infants with low activity AK₁2-1 phenotype than in those with high activity AK₁1 phenotype. The difference between AK₁ and AK₁2-1 is well marked only in newborns with a gestational age greater than 38 weeks and it is not influenced by sex, maternal age and maternal smoking. A similar pattern is observed with maternal AK₁ phenotype. These results suggest that the difference in enzymatic activity between AK₁ phenotypes influencing the equilibrium among ATP, ADP, AMP and adenosine could have an important role in a balanced development of feto-placental unit. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  5. Compensatory placental growth after restricted maternal nutrition in early pregnancy.

    Science.gov (United States)

    Lumey, L H

    1998-01-01

    This study examined the effects of undernutrition in pregnancy on fetal and placental growth among infants born in 1944-1946 in The Netherlands, including infants born during the war-induced Dutch famine of 1944-1945. There was an increase in placental weight, but not in birthweight, in infants whose mothers' nutrition was compromised around conception or in the first trimester of pregnancy. Therefore, the placental index was also increased. Compared to pre-famine controls, the relative increase after first trimester exposure to undernutrition was larger in the northern part of the country (5.2 per cent, 95 per cent confidence interval 1.4, 9.0) where nutritional deprivation was presumably moderate compared to the west (3.5 per cent, 95 per cent confidence interval 0.2, 7.2) where nutritional deprivation was severe. The increase in placental weight is interpreted as compensatory for the reduction in maternal caloric intake. Whereas this suggests that pregnancy undernutrition can stimulate compensatory placental growth, the latter was only seen after first trimester undernutrition, which does not affect infant size at birth. For these infants, therefore, birthweight is not an appropriate proxy measure of undernutrition in pregnancy. These factors need to be considered in future studies relating pregnancy nutrition to adult health outcomes.

  6. Placental pathologies in fetal MRI with pathohistological correlation.

    Science.gov (United States)

    Linduska, N; Dekan, S; Messerschmidt, A; Kasprian, G; Brugger, P C; Chalubinski, K; Weber, M; Prayer, D

    2009-06-01

    The purpose of this study was to evaluate whether currently available fetal Magnetic Resonance Imaging (MRI/MR) techniques are sufficient for the assessment of placental pathologies. We hypothesized that placental pathologies as detected and evaluated by MRI, would correlate with histological findings. In a retrospective study, 45 singleton pregnancies from 19 to 35 gestational weeks, with placental pathologies on MR scans, were included. MRI was performed on a 1.5T unit using T2-, T1-, and diffusion-weighted and echo-planar sequences. Pathologies were categorized into infarction with/without hemorrhagic components, subchorionic/intervillous thrombi/hemorrhages, retroplacental hematoma, massive perivillous fibrin deposition, and chorioamnionitis. Pathohistological examination was performed postnatally within a median of seven days between MR examination and delivery. Pathologically, 26 placentas showed infarctions (96.2% on MR scans), two retroplacental hematomas were detected by MRI and confirmed by pathology, and 9 of 14 subchorionic hematomas were confirmed. Six of eight intervillous hemorrhages were seen on MRI, and three of six cases of severe chorioamnionitis were diagnosed prenatally. Placental hemorrhages (retroplacental hematoma, intervillous thrombi, subchorionic hematoma), and ischemic lesions could be detected with fetal MRI, while chorioamnionitis and even massive perivillous fibrin deposition showed few signal changes, probably reflecting small macroscopic changes in the placenta. Fetal MRI, therefore, seems to be a promising tool for the assessment of placental insufficiency.

  7. A higher-level MRP supertree of placental mammals

    Directory of Open Access Journals (Sweden)

    Bininda-Emonds Olaf RP

    2006-11-01

    Full Text Available Abstract Background The higher-level phylogeny of placental mammals has long been a phylogenetic Gordian knot, with disagreement about both the precise contents of, and relationships between, the extant orders. A recent MRP supertree that favoured 'outdated' hypotheses (notably, monophyly of both Artiodactyla and Lipotyphla has been heavily criticised for including low-quality and redundant data. We apply a stringent data selection protocol designed to minimise these problems to a much-expanded data set of morphological, molecular and combined source trees, to produce a supertree that includes every family of extant placental mammals. Results The supertree is well-resolved and supports both polyphyly of Lipotyphla and paraphyly of Artiodactyla with respect to Cetacea. The existence of four 'superorders' – Afrotheria, Xenarthra, Laurasiatheria and Euarchontoglires – is also supported. The topology is highly congruent with recent (molecular phylogenetic analyses of placental mammals, but is considerably more comprehensive, being the first phylogeny to include all 113 extant families without making a priori assumptions of suprafamilial monophyly. Subsidiary analyses reveal that the data selection protocol played a key role in the major changes relative to a previously published higher-level supertree of placentals. Conclusion The supertree should provide a useful framework for hypothesis testing in phylogenetic comparative biology, and supports the idea that biogeography has played a crucial role in the evolution of placental mammals. Our results demonstrate the importance of minimising poor and redundant data when constructing supertrees.

  8. Heterogeneous models place the root of the placental mammal phylogeny.

    Science.gov (United States)

    Morgan, Claire C; Foster, Peter G; Webb, Andrew E; Pisani, Davide; McInerney, James O; O'Connell, Mary J

    2013-09-01

    Heterogeneity among life traits in mammals has resulted in considerable phylogenetic conflict, particularly concerning the position of the placental root. Layered upon this are gene- and lineage-specific variation in amino acid substitution rates and compositional biases. Life trait variations that may impact upon mutational rates are longevity, metabolic rate, body size, and germ line generation time. Over the past 12 years, three main conflicting hypotheses have emerged for the placement of the placental root. These hypotheses place the Atlantogenata (common ancestor of Xenarthra plus Afrotheria), the Afrotheria, or the Xenarthra as the sister group to all other placental mammals. Model adequacy is critical for accurate tree reconstruction and by failing to account for these compositional and character exchange heterogeneities across the tree and data set, previous studies have not provided a strongly supported hypothesis for the placental root. For the first time, models that accommodate both tree and data set heterogeneity have been applied to mammal data. Here, we show the impact of accurate model assignment and the importance of data sets in accommodating model parameters while maintaining the power to reject competing hypotheses. Through these sophisticated methods, we demonstrate the importance of model adequacy, data set power and provide strong support for the Atlantogenata over other competing hypotheses for the position of the placental root.

  9. Differential Loss of Embryonic Globin Genes during the Radiation of Placental Mammals

    National Research Council Canada - National Science Library

    Juan C. Opazo; Federico G. Hoffmann; Jay F. Storz

    2008-01-01

    ...-globin gene family of placental mammals. By analyzing genomic sequence data from representatives of each of the main superordinal clades of placental mammals, we were able to reconstruct pathways of gene family evolution during the basal...

  10. Formation of a ruthenium(IV)-oxo complex by electron-transfer oxidation of a coordinatively saturated ruthenium(II) complex and detection of oxygen-rebound intermediates in C-H bond oxygenation.

    Science.gov (United States)

    Kojima, Takahiko; Nakayama, Kazuya; Ikemura, Kenichiro; Ogura, Takashi; Fukuzumi, Shunichi

    2011-08-03

    A coordinatively saturated ruthenium(II) complex having tetradentate tris(2-pyridylmethyl)amine (TPA) and bidentate 2,2'-bipyridine (bpy), [Ru(TPA)(bpy)](2+) (1), was oxidized by a Ce(IV) ion in H(2)O to afford a Ru(IV)-oxo complex, [Ru(O)(H(+)TPA)(bpy)](3+) (2). The crystal structure of the Ru(IV)-oxo complex 2 was determined by X-ray crystallography. In 2, the TPA ligand partially dissociates to be in a facial tridentate fashion and the uncoordinated pyridine moiety is protonated. The spin state of 2, which showed paramagnetically shifted NMR signals in the range of 60 to -20 ppm, was determined to be an intermediate spin (S = 1) by the Evans' method with (1)H NMR spectroscopy in acetone-d(6). The reaction of 2 with various oraganic substrates in acetonitrile at room temperature afforded oxidized and oxygenated products and a solvent-bound complex, [Ru(H(+)TPA)(bpy)(CH(3)CN)], which is intact in the presence of alcohols. The oxygenation reaction of saturated C-H bonds with 2 proceeds by two-step processes: the hydrogen abstraction with 2, followed by the dissociation of the alcohol products from the oxygen-rebound complexes, Ru(III)-alkoxo complexes, which were successfully detected by ESI-MS spectrometry. The kinetic isotope effects in the first step for the reaction of dihydroanthrathene (DHA) and cumene with 2 were determined to be 49 and 12, respectively. The second-order rate constants of C-H oxygenation in the first step exhibited a linear correlation with bond dissociation energies of the C-H bond cleavage.

  11. Effect of drug efflux transporters on placental transport of antiretroviral agent abacavir.

    Science.gov (United States)

    Neumanova, Zuzana; Cerveny, Lukas; Greenwood, Susan L; Ceckova, Martina; Staud, Frantisek

    2015-11-01

    Abacavir is as a frequent part of combination antiretroviral therapy used in pregnant women. The aim of this study was to investigate, using in vitro, in situ and ex vivo experimental approaches, whether the transplacental pharmacokinetics of abacavir is affected by ATP-binding cassette (ABC) efflux transporters functionally expressed in the placenta: P-glycoprotein (ABCB1), breast cancer resistance protein (ABCG2), multidrug resistance-associated protein 2 (ABCC2) and multidrug resistance-associated protein 5 (ABCC5). In vitro transport assays revealed that abacavir is a substrate of human ABCB1 and ABCG2 transporters but not of ABCC2 or ABCC5. In addition, in situ experiments using dually perfused rat term placenta confirmed interactions of abacavir with placental Abcb1/Abcg2. In contrast, uptake studies in human placental villous fragments did not reveal any interaction of abacavir with efflux transporters suggesting a large contribution of passive diffusion and/or influx mechanisms to net transplacental abacavir transfer.

  12. Placental abnormalities associated with post-natal mortality in sheep somatic cell clones.

    Science.gov (United States)

    Loi, Pasqualino; Clinton, Michael; Vackova, Irena; Fulka, Josef; Feil, Robert; Palmieri, Chiara; Della Salda, Leonardo; Ptak, Grazyna

    2006-04-01

    We report on cloning experiments designed to explore the causes of peri- and post-natal mortality of cloned lambs. A total of 93 blastocysts obtained by nuclear transfer of somatic cells (granulosa cells) were transferred into 41 recipient ewes, and pregnancies were monitored by ultrasound scanning. In vitro derived, fertilized embryos (IVF, n=123) were also transferred to assess oocyte competence, and naturally mated ewes (n=120) were analysed as well. Cloned embryos developed to the blastocyst stage and implanted at the same rate as IVF embryos. After day 30 of gestation, however, dramatic losses occurred, and only 12 out of 93 (13%) clones reached full-term development, compared to 51 out of 123 (41.6%) lambs born from the IVF control embryos. Three full-term lamb clones were delivered stillborn, as a result of placental degeneration. A further five clone recipients developed hydroallantois. Their lambs died within 24h following delivery by caesarian section, and displayed degenerative lesions in liver and kidney resulting from the severe hydroallantois. One set of twins was delivered by assisted parturition at day 150, but died 24h later due to respiratory distress syndrome. The remaining two clone recipients underwent caesarian section, and the corresponding two lambs displayed signs of respiratory dysfunction and died at approximately 1 month of age due to a bacterial complication. Blood samples collected from the cloned lambs after birth revealed a wide range of abnormalities indicative of kidney and liver dysfunction. Macroscopical and histopathological examination of the placentae revealed a marked reduction in vascularization, particularly at the apex of the villous processes, as well as a loss of differentiation of the trophoblastic epithelium. Our results strongly suggest that post-mortality in cloned lambs is mainly caused by placental abnormalities.

  13. Social disparity affects the incidence of placental abruption among multiparous but not nulliparous women

    DEFF Research Database (Denmark)

    Räisänen, Sari; Gissler, Mika; Nielsen, Henriette Svarre

    2013-01-01

    To identify risk factors for placental abruption and to evaluate associations between adverse perinatal outcomes and placental abruption stratified by parity among women with singleton births from 1991 to 2010 in Finland.......To identify risk factors for placental abruption and to evaluate associations between adverse perinatal outcomes and placental abruption stratified by parity among women with singleton births from 1991 to 2010 in Finland....

  14. Role of the endothelium in placental dysfunction after fetal cardiac bypass.

    Science.gov (United States)

    Reddy, V M; McElhinney, D B; Rajasinghe, H A; Liddicoat, J R; Hendricks-Munoz, K; Fineman, J R; Hanley, F L

    1999-02-01

    Fetal cardiac bypass causes placental dysfunction, characterized by increased placental vascular resistance, decreased placental blood flow, hypoxia, and acidosis. Vasoactive factors produced by the vascular endothelium, such as nitric oxide and endothelin 1, are important regulators of placental vascular tone and may contribute to this placental dysfunction. To investigate the role of the vascular endothelium in placental dysfunction related to fetal cardiac bypass, we studied 3 groups of fetal sheep. In the first group (n = 7) we determined placental hemodynamic responses before and after bypass to an endothelium-dependent vasodilator (acetylcholine), an endothelium-independent vasodilator (nitroprusside), and endothelin 1. In the second group (n = 8) a nonspecific endothelin receptor blocker (PD 145065) was administered and placental hemodynamic values were measured before and after bypass. In the third group (n = 5) endothelin 1 levels were measured before and after bypass. Before fetal cardiac bypass exogenous endothelin 1 decreased placental blood flow by 9% and increased placental resistance by 9%. After bypass endothelin 1 decreased placental flow by 47% and increased resistance by 106%. There was also a significant attenuation of the placental vascular relaxation response to acetylcholine after bypass, whereas the response to nitroprusside was not significantly altered. In fetuses that received the PD 145065, placental vascular resistance increased significantly less than in control fetuses (28% versus 62%). Similarly, placental blood flow decreased significantly more (from 6. 3 +/- 3.1 to 28.3 +/- 10.4 pg/mL; P =.01) in control fetuses than in fetuses receiving PD 145065 (33% versus 20%). Umbilical venous endothelin 1 levels increased significantly in fetuses exposed to fetal bypass but did not change in control fetuses. The basal endothelial regulatory mechanisms of placental vascular tone were deranged after fetal cardiac bypass. Endothelin receptor

  15. Blocking Endogenous Leukemia Inhibitory Factor During Placental Development in Mice Leads to Abnormal Placentation and Pregnancy Loss.

    Science.gov (United States)

    Winship, Amy; Correia, Jeanne; Krishnan, Tara; Menkhorst, Ellen; Cuman, Carly; Zhang, Jian-Guo; Nicola, Nicos A; Dimitriadis, Evdokia

    2015-08-14

    The placenta forms the interface between the maternal and fetal circulation and is critical for the establishment of a healthy pregnancy. Specialized trophoblast cells derived from the embryonic trophectoderm play a pivotal role in the establishment of the placenta. Leukemia inhibitory factor (LIF) is one of the predominant cytokines present in the placenta during early pregnancy. LIF has been shown to regulate trophoblast adhesion and invasion in vitro, however its precise role in vivo is unknown. We hypothesized that LIF would be required for normal placental development in mice. LIF and LIFRα were immunolocalized to placental trophoblasts and fetal vessels in mouse implantation sites during mid-gestation. Temporally blocking LIF action during specific periods of placental development via intraperitoneal administration of our specific LIFRα antagonist, PEGLA, resulted in abnormal placental trophoblast and vascular morphology and reduced activated STAT3 but not ERK. Numerous genes regulating angiogenesis and oxidative stress were altered in the placenta in response to LIF inhibition. Pregnancy viability was also significantly compromised in PEGLA treated mice. Our data suggest that LIF plays an important role in placentation in vivo and the maintenance of healthy pregnancy.

  16. Indications of anti-HY immunity in recurrent placental abruption

    DEFF Research Database (Denmark)

    Nielsen, Henriette Svarre; Mogensen, Marie; Steffensen, Rudi

    2007-01-01

    PROBLEM: Placental abruption is a potential life-threatening condition for both the fetus and the mother, being significantly more common in pregnancies with male fetuses. The pathogenesis of placental abruption remains unknown. However, some recent reports point toward a maternal immune response...... the fetus died. Seven patients (88%) had first-born boys, and 15 abruptions (68%) involved male fetuses. All patients with a first-born boy, except one, had HLA-class II alleles known to restrict CD4+ T-cell responses against male-specific minor histocompatibility (HY)-antigens (HLA-DRB1*15, HLA-DRB3...... abruption is exclusively almost preceded by the birth of a boy and the majority of patients have HLA-class II known to restrict CD4 T-cell reactions against HY-antigens. This indicates that maternal immunological responses against HY-antigens play a role in recurrent placental abruption. Udgivelsesdato...

  17. Placental leptin gene methylation and macrosomia during normal pregnancy.

    Science.gov (United States)

    Xu, Xinyun; Yang, Xinjun; Liu, Ziwei; Wu, Kele; Liu, Zheng; Lin, Chong; Wang, Yuhuan; Yan, Hongtao

    2014-03-01

    The present study examined the placental leptin (LEP) DNA methylation and mRNA levels in macrosomic infants from normal pregnancies. In total, 49 neonates with macrosomia, i.e., high birth weights of ≥ 4,000 g, and 52 neonates with normal birth weights between 2,500 g and 4,000 g were recruited from The Second Affiliated Hospital of Wenzhou Medical University (Wenzhou, Zhejiang) in China. Placental LEP promoter methylation and LEP transcript levels were determined by Sequenom MassARRAY and quantitative PCR, respectively. LEP promoter methylation and mRNA levels were not significantly different between the individuals with macrosomia and the controls. However, stratification revealed that individual CpG dinucleotides were hypermethylated in macrosomia (Pmacrosomia following a normal pregnancy and under certain conditions. However, placental LEP expression was not affected.

  18. The feto-placental endothelium in pregnancy pathologies.

    Science.gov (United States)

    Wadsack, Christian; Desoye, Gernot; Hiden, Ursula

    2012-05-01

    This review aims to provide a comprehensive summary of the aspects of endothelial and vascular dysfunction in the feto-placental vasculature occurring in pregnancy pathologies. This endothelium is continuous with the fetal circulation. Its function and potential dysfunction in pathologies will have a profound impact on fetal development. Gestational diabetes mellitus represents one of these pathologies, in which its associated metabolic derangements will alter feto-placental endothelial functions. These, in turn, may result in functional changes of the placenta, which may entail impaired fetal development. By contrast, changes in the feto-placental vasculature observed in cases of fetal growth restriction and preeclampsia may be causative (fetal growth restriction) or secondary (preeclampsia) for the pathology.

  19. Placental pseudo-malignancy from a DNA methylation perspective: unanswered questions and future directions

    Directory of Open Access Journals (Sweden)

    Boris eNovakovic

    2013-12-01

    Full Text Available The growing fetus is dependent on adequate placental function for delivery of essential nutrients and oxygen, and for waste removal. The placenta also plays an important protective role; shielding the developing baby from the maternal immune system and adverse environmental exposures. Fundamental to these processes is correct invasion of the decidua and remodelling of maternal vasculature, each of which show remarkable parallels to tumourogenesis, with the obvious exception that the former is usually a tightly controlled process. It is not surprising that these physiological similarities are mirrored in gene expression and epigenetic parallels, many not found in any other aspect of human development. In this perspective, we summarise known DNA methylation similarities between placenta and human tumours, and discuss the implications and knowledge gaps associated with these findings. We also speculate on the potential origin of common DNA methylation features in these two disparate aspects of human physiology.

  20. Embryonic rather than extraembryonic tissues have more impact on the development of placental hyperplasia in cloned mice.

    Science.gov (United States)

    Miki, H; Wakisaka, N; Inoue, K; Ogonuki, N; Mori, M; Kim, J-M; Ohta, A; Ogura, A

    2009-06-01

    Somatic cell cloning by nuclear transfer (NT) in mice is associated with hyperplastic placentas at term. To dissect the effects of embryonic and extraembryonic tissues on this clone-associated phenotype, we constructed diploid (2n) fused with () tetraploid (4n) chimeras from NT- and fertilization-derived (FD) embryos. Generally, the 4n cells contributed efficiently to all the extraembryonic tissues but not to the embryo itself. Embryos constructed by 2n NT4n FD aggregation developed hyperplastic placentas (0.33+/-0.22 g) with a predominant contribution by NT-derived cells. Even when the population of FD-derived cells in placentas was increased using multiple FD embryos (up to four) for aggregation, most placentas remained hyperplastic (0.36+/-0.13 g). By contrast, placentas of the reciprocal combination, 2n FD4n NT, were less hyperplastic (0.15+/-0.02 g). These nearly normal-looking placentas had a large proportion of NT-derived cells. Thus, embryonic rather than extraembryonic tissues had more impact on the onset of placental hyperplasia, and that the abnormal placentation in clones occurs in a noncell-autonomous manner. These findings suggest that for improvement of cloning efficiency we should understand the mechanisms regulating placentation, especially those of embryonic origin that might control the proliferation of trophoblastic lineage cells.

  1. Loss of Thrombomodulin in Placental Dysfunction in Preeclampsia.

    Science.gov (United States)

    Turner, Rosanne J; Bloemenkamp, Kitty W M; Bruijn, Jan A; Baelde, Hans J

    2016-04-01

    Preeclampsia is a pregnancy-specific syndrome characterized by placental dysfunction and an angiogenic imbalance. Systemically, levels of thrombomodulin, an endothelium- and syncytiotrophoblast-bound protein that regulates coagulation, inflammation, apoptosis, and tissue remodeling, are increased. We aimed to investigate placental thrombomodulin dysregulation and consequent downstream effects in the pathogenesis of preeclampsia. Placentas from 28 preeclampsia pregnancies, 30 uncomplicated pregnancies, and 21 pregnancies complicated by growth restriction as extra controls were included. Immunohistochemical staining of thrombomodulin, caspase-3, and fibrin was performed. Placental mRNA expression of thrombomodulin, inflammatory markers, matrix metalloproteinases 2 and 9, and soluble Flt-1 were measured with quantitative polymerase chain reaction. Thrombomodulin mRNA expression was determined in vascular endothelial growth factor-transfected trophoblast cell lines. Thrombomodulin protein and mRNA expression were decreased in preeclampsia as compared with both control groups (P=0.001). Thrombomodulin mRNA expression correlated with maternal body mass index (Ppreeclampsia. An increase in placental apoptotic cells was associated with preeclampsia (Ppreeclampsia, but not with fibrin deposits or inflammatory markers. Placental soluble Flt-1 expression correlated with decreased thrombomodulin expression. Vascular endothelial growth factor induced upregulation of thrombomodulin expression in trophoblast cells. Decreased thrombomodulin expression in preeclampsia may play a role in placental dysfunction in preeclampsia and is possibly caused by an angiogenic imbalance. Hypertension and obesity are associated with thrombomodulin downregulation. These results set the stage for further basic and clinical research on thrombomodulin in the pathogenesis of preeclampsia and other syndromes characterized by endothelial dysfunction. © 2016 American Heart Association, Inc.

  2. Macrosomia has its roots in early placental development.

    Science.gov (United States)

    Schwartz, N; Quant, H S; Sammel, M D; Parry, S

    2014-09-01

    We sought to determine if early placental size, as measured by 3-dimensional ultrasonography, is associated with an increased risk of delivering a macrosomic or large-for-gestational age (LGA) infant. We prospectively collected 3-dimensional ultrasound volume sets of singleton pregnancies at 11-14 weeks and 18-24 weeks. Birth weights were collected from the medical records. After delivery, the ultrasound volume set were used to measure the placental volume (PV) and placental quotient (PQ = PV/gestational age), as well as the mean placental and chorionic diameters (MPD and MCD, respectively). Placental measures were analyzed as predictors of macrosomia (birth weight ≥4000 g) and LGA (birth weight ≥90th percentile). The 578 pregnancies with first trimester volumes included 44 (7.6%) macrosomic and 43 (7.4%) LGA infants. 373 subjects also had second trimester volumes available. A higher PV and PQ were both significantly associated with macrosomia and LGA in both the first and second trimesters. Second trimester MPD was significantly associated with both outcomes as well, while second trimester MCD was only associated with LGA. The above associations remained significant after adjusting for maternal demographic variables such as race, ethnicity, age and diabetes. Adjusted models yielded moderate prediction of macrosomia and LGA (AUC: 0.71-0.77). Sonographic measurement of the early placenta can identify pregnancies at greater risk of macrosomia and LGA. Macrosomia and LGA are already determined in part by early placental growth and development. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Association between PAPP-A and placental thickness

    Directory of Open Access Journals (Sweden)

    Elaheh Mesdaghi-nia

    2016-06-01

    Full Text Available Background: Measuring of maternal serum pregnancy-associated plasma protein-A (PAPP-A in first trimester can be a way for early detection of adverse prenatal outcome due to faulty placenta. Objective: The aim was to Determination of association between placental thickness in second trimester with low level of PAPP-A in first trimester. Materials and Methods: In this cohort study, serum PAPP-A of 187 pregnant women was measured in the first trimester of pregnancy. Patients who had PAPP-A ≤0.8 MOM were in exposed and others who had PAPP-A >0.8 defined as unexposed group. The criteria of placental thickness in ultrasound study was thickness of 4 cm or more than 50% of placental length. Results: Of 187 patients, 87 patients had PAPP-A >0.8 and 93 patients had PAPP-A ≤0.8. Women with low levels of PAPP-A in the first trimester, had an increased incidence placental thickness of 34.4%, whereas another group had about 15% (p=0.002. Also, PAPP-A levels had acceptable sensitivity and specificity for placental thickness detection (71.1% and 54.8%, respectively. Conclusion: Our study showed that serum level of PAPP-A generally was low (≤0.8 in women with a thick placenta (>4 cm or >50% of placental length. The first trimester of pregnancy measurement of PAPP-A will be more predictable for healthy placenta.

  4. HIV-1 Nef breaches placental barrier in rat model.

    Science.gov (United States)

    Singh, Poonam; Agnihotri, Saurabh Kumar; Tewari, Mahesh Chandra; Kumar, Sadan; Sachdev, Monika; Tripathi, Raj Kamal

    2012-01-01

    The vertical transmission of HIV-1 from the mother to fetus is known, but the molecular mechanism regulating this transmission is not fully characterized. The fetus is highly protected by the placenta, which does not permit microbial pathogens to cross the placental barrier. In the present study, a rat model was established to observe the effect of HIV-1 protein Nef on placental barrier. Evans blue dye was used to assay permeability of placental barrier and fourteen day pregnant Sprague Dawley rats were injected intravenously with 2% Evans blue dye along with various concentrations of recombinant Nef. After an hour, animals were sacrificed and dye migration was observed through the assimilation of peripheral blood into fetus. Interestingly, traces of recombinant Nef protein were detected in the embryo as well as amniotic fluid and amniotic membrane along with placenta and uterus. Our study indicates that recombinant HIV-1-Nef protein breaches the placental barrier and allows the migration of Evans blue dye to the growing fetus. Further the concentration of Nef protein in blood is directly proportional to the intensity of dye migration and to the amount of Nef protein detected in uterus, placenta, amniotic membrane, amniotic fluid and embryo. Based on this study, it can be concluded that the HIV-1 Nef protein has a direct effect on breaching of the placental barrier in the model we have established in this study. Our observations will be helpful to understand the molecular mechanisms related to this breach of placental barrier by Nef in humans and may be helpful to identify specific Nef inhibitors.

  5. Analytical theory of oxygen transport in the human placenta.

    Science.gov (United States)

    Serov, A S; Salafia, C M; Filoche, M; Grebenkov, D S

    2015-03-07

    We propose an analytical approach to solving the diffusion-convection equations governing oxygen transport in the human placenta. We show that only two geometrical characteristics of a placental cross-section, villi density and the effective villi radius, are needed to predict fetal oxygen uptake. We also identify two combinations of physiological parameters that determine oxygen uptake in a given placenta: (i) the maximal oxygen inflow of a placentone if there were no tissue blocking the flow and (ii) the ratio of transit time of maternal blood through the intervillous space to oxygen extraction time. We derive analytical formulas for fast and simple calculation of oxygen uptake and provide two diagrams of efficiency of oxygen transport in an arbitrary placental cross-section. We finally show that artificial perfusion experiments with no-hemoglobin blood tend to give a two-orders-of-magnitude underestimation of the in vivo oxygen uptake and that the optimal geometry for such setup alters significantly. The theory allows one to adjust the results of artificial placenta perfusion experiments to account for oxygen-hemoglobin dissociation. Combined with image analysis techniques, the presented model can give an easy-to-use tool for prediction of the human placenta efficiency.

  6. Placental histopathological changes associated with Plasmodium vivax infection during pregnancy.

    Directory of Open Access Journals (Sweden)

    Rodrigo M Souza

    Full Text Available Histological evidence of Plasmodium in the placenta is indicative of placental malaria, a condition associated with severe outcomes for mother and child. Histological lesions found in placentas from Plasmodium-exposed women include syncytial knotting, syncytial rupture, thickening of the placental barrier, necrosis of villous tissue and intervillositis. These histological changes have been associated with P. falciparum infections, but little is known about the contribution of P. vivax to such changes. We conducted a cross-sectional study with pregnant women at delivery and assigned them to three groups according to their Plasmodium exposure during pregnancy: no Plasmodium exposure (n = 41, P. vivax exposure (n = 59 or P. falciparum exposure (n = 19. We evaluated their placentas for signs of Plasmodium and placental lesions using ten histological parameters: syncytial knotting, syncytial rupture, placental barrier thickness, villi necrosis, intervillous space area, intervillous leucocytes, intervillous mononucleates, intervillous polymorphonucleates, parasitized erythrocytes and hemozoin. Placentas from P. vivax-exposed women showed little evidence of Plasmodium or hemozoin but still exhibited more lesions than placentas from women not exposed to Plasmodium, especially when infections occurred twice or more during pregnancy. In the Brazilian state of Acre, where diagnosis and primary treatment are readily available and placental lesions occur in the absence of detected placental parasites, relying on the presence of Plasmodium in the placenta to evaluate Plasmodium-induced placental pathology is not feasible. Multivariate logistic analysis revealed that syncytial knotting (odds ratio [OR], 4.21, P = 0.045, placental barrier thickness (OR, 25.59, P = 0.021 and mononuclear cells (OR, 4.02, P = 0.046 were increased in placentas from P. vivax-exposed women when compared to women not exposed to Plasmodium during pregnancy. A

  7. Placental mesenchymal dysplasia associated with hepatic and pulmonary hamartoma.

    Science.gov (United States)

    Tortoledo, Maria; Galindo, A; Ibarrola, C

    2010-01-01

    This report describes a 31-week stillborn female infant with placental mesenchymal dysplasia (PMD) in association with hepatic mesenchymal hamartoma (HMH) and pulmonary hamartoma. Placental mesenchymal dysplasia was initially misdiagnosed as a partial mole. However, histologically, no trophoblastic proliferation or inclusions were observed. Differential diagnosis of the hepatic mass with similar tumors is discussed. To our knowledge, this is the first case of lung hamartoma reported in a fetus and the first case related to PMD and HMH. A common anomalous development of the mesoderm, a reparative post-injury process and a genetic mechanism, have been proposed to explain their pathogenesis.

  8. Metabolism of bupropion by baboon hepatic and placental microsomes

    OpenAIRE

    2011-01-01

    The aim of this investigation was to determine the biotransformation of bupropion by baboon hepatic and placental microsomes, identify the enzyme(s) catalyzing the reaction(s) and determine its kinetics. Bupropion was metabolized by baboon hepatic and placental microsomes to hydroxybupropion (OH-BUP), threo- (TB) and erythrohydrobupropion (EB). OH-bupropion was the major metabolite formed by hepatic microsomes (Km 36 ± 6 µM, Vmax 258 ± 32 pmol mg protein−1 min−1), however the formation of OH-...

  9. Developmental genes during placentation: insights from mouse mutants

    Institute of Scientific and Technical Information of China (English)

    Jinhu a LU; Qiang WANG; Bingyan WANG; Fengchao WANG; Haibin WANG

    2011-01-01

    Placenta,a temporary organ first formed during the development of a new life is essential for the survival and growth of the fetus in eutherian mammals.It serves as an interface for the exchange of nutrients,gases and wastes between the maternal and fetal compartments.During the past decades,studies employing gene-engineered mouse mutants have revealed a wide range of signaling molecules governing the trophoblast development and function during placentation under various pathophysiological conditions.Here,we summarize the recent progress with particular respect to the involvement of developmental genes during placentation.

  10. Influence of placental position on obstetric morbidity in placenta previa

    Directory of Open Access Journals (Sweden)

    Shripad S. Hebbar

    2014-06-01

    Conclusions: It is difficult to assign a maternal or perinatal morbidity risk to a particular type of placental location. The need for specialized surgical intervention such as uterine / internal iliac artery ligation, peripartum hysterectomy can arise irrespective of placental location, whether underneath the surgical incision (anterior, proximity to main uterine trunks (lateral or encountered after the delivery of the baby (posterior. Pregnancies complicated by placenta previa must be delivered in the hospitals having expertise of senior and skilled surgeons and well equipped blood bank and good neonatal intensive care unit. [Int J Reprod Contracept Obstet Gynecol 2014; 3(3.000: 585-591

  11. Metallothionein expression in placental tissue in Menkes' disease

    DEFF Research Database (Denmark)

    Hærslev, T.; Krag Jacobsen, G.; Horn, N.

    1995-01-01

    Menkes' disease is a recessive X-linked disturbance of copper metabolism, resulting in accumulation of copper in several extra-hepatic tissues including the placenta. Metallothionein (MT) is a low-molecular weight protein with a high affinity for group II metal ions, such as copper. Its synthesis....... The avidin-biotin-complex (ABC)-technique was used. The copper content was measured by neutron activation analysis (NAA). In all placental tissue sections positive MT immunostaining appeared only in the trophoblast and only in proliferating cells. In placental tissue sections obtained from foetuses...

  12. Infant sex-specific placental cadmium and DNA methylation associations

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, April F., E-mail: april.mohanty@va.gov [Cardiovascular Health Research Unit, University of Washington, 1730 Minor Ave, Seattle, WA 98101 (United States); Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA (United States); Farin, Fred M., E-mail: freddy@u.washington.edu [Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, 4225 Roosevelt Way N.E., Suite #100, Seattle, WA 98105 (United States); Bammler, Theo K., E-mail: tbammler@u.washington.edu [Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, 4225 Roosevelt Way N.E., Suite #100, Seattle, WA 98105 (United States); MacDonald, James W., E-mail: jmacdon@uw.edu [Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, 4225 Roosevelt Way N.E., Suite #100, Seattle, WA 98105 (United States); Afsharinejad, Zahra, E-mail: zafshari@u.washington.edu [Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, 4225 Roosevelt Way N.E., Suite #100, Seattle, WA 98105 (United States); Burbacher, Thomas M., E-mail: tmb@uw.edu [Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Box: 357234, 1705 N.E. Pacific Street, Seattle, WA 98195 (United States); Siscovick, David S., E-mail: dsiscovick@nyam.org [Cardiovascular Health Research Unit, University of Washington, 1730 Minor Ave, Seattle, WA 98101 (United States); Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA (United States); Department of Medicine, University of Washington, Seattle, WA (United States); and others

    2015-04-15

    Background: Recent evidence suggests that maternal cadmium (Cd) burden and fetal growth associations may vary by fetal sex. However, mechanisms contributing to these differences are unknown. Objectives: Among 24 maternal-infant pairs, we investigated infant sex-specific associations between placental Cd and placental genome-wide DNA methylation. Methods: We used ANOVA models to examine sex-stratified associations of placental Cd (dichotomized into high/low Cd using sex-specific Cd median cutoffs) with DNA methylation at each cytosine-phosphate-guanine site or region. Statistical significance was defined using a false discovery rate cutoff (<0.10). Results: Medians of placental Cd among females and males were 5 and 2 ng/g, respectively. Among females, three sites (near ADP-ribosylation factor-like 9 (ARL9), siah E3 ubiquitin protein ligase family member 3 (SIAH3), and heparin sulfate (glucosamine) 3-O-sulfotransferase 4 (HS3ST4) and one region on chromosome 7 (including carnitine O-octanoyltransferase (CROT) and TP5S target 1 (TP53TG1)) were hypomethylated in high Cd placentas. Among males, high placental Cd was associated with methylation of three sites, two (hypomethylated) near MDS1 and EVI1 complex locus (MECOM) and one (hypermethylated) near spalt-like transcription factor 1 (SALL1), and two regions (both hypomethylated, one on chromosome 3 including MECOM and another on chromosome 8 including rho guanine nucleotide exchange factor (GEF) 10 (ARHGEF10). Differentially methylated sites were at or close to transcription start sites of genes involved in cell damage response (SIAH3, HS3ST4, TP53TG1) in females and cell differentiation, angiogenesis and organ development (MECOM, SALL1) in males. Conclusions: Our preliminary study supports infant sex-specific placental Cd-DNA methylation associations, possibly accounting for previously reported differences in Cd-fetal growth associations across fetal sex. Larger studies are needed to replicate and extend these

  13. Human placental alkaline phosphatase electrophoretic alleles: Quantitative studies

    Science.gov (United States)

    Lucarelli, Paola; Scacchi, Renato; Corbo, Rosa Maria; Benincasa, Alberto; Palmarino, Ricciotti

    1982-01-01

    Human placental alkaline phosphatase (ALP) activity has been determined in specimens obtained from 562 Italian subjects. The mean activities of the three common homozygotes (Pl 2 = 4.70 ± 0.24, Pl 1 = 4.09 ± 0.08, and Pl 3 = 2.15 ± 0.71 μmol of p-nitrophenol produced) were significantly different. The differences among the various allelic forms account for 10% of the total quantitative variation of the human placental alkaline phosphatase. PMID:7072721

  14. The mechanism by which oxygen and cytochrome c increase the rate of electron transfer from cytochrome a to cytochrome a3 of cytochrome c oxidase.

    Science.gov (United States)

    Bickar, D; Turrens, J F; Lehninger, A L

    1986-11-05

    When cytochrome c oxidase is isolated from mitochondria, the purified enzyme requires both cytochrome c and O2 to achieve its maximum rate of internal electron transfer from cytochrome a to cytochrome a3. When reductants other than cytochrome c are used, the rate of internal electron transfer is very slow. In this paper we offer an explanation for the slow reduction of cytochrome a3 when reductants other than cytochrome c are used and for the apparent allosteric effects of cytochrome c and O2. Our model is based on the conventional understanding of cytochrome oxidase mechanism (i.e. electron transfer from cytochrome a/CuA to cytochrome a3/CuB), but assumes a relatively rapid two-electron transfer between cytochrome a/CuA and cytochrome a3/CuB and a thermodynamic equilibrium in the "resting" enzyme (the enzyme as isolated) which favors reduced cytochrome a and oxidized cytochrome a3. Using the kinetic constants that are known for this reaction, we find that the activating effects of O2 and cytochrome c on the rate of electron transfer from cytochrome a to cytochrome a3 conform to the predictions of the model and so provide no evidence of any allosteric effects or control of cytochrome c oxidase by O2 or cytochrome c.

  15. Neonatal cerebral oxygenation is not linked to foetal vasculitis and predicts intraventricular haemorrhage in preterm infants

    DEFF Research Database (Denmark)

    Sorensen, Line C; Maroun, Lisa L; Borch, Klaus;

    2008-01-01

    Aim: The aim of the study was to compare the cerebral tissue oxygenation index (c-TOI) measured by near infrared spectroscopy (NIRS) in infants with and without foetal vasculitis. Methods: Twenty-four infants with placental signs of a foetal inflammatory response (FIR), foetal vasculitis, were.......002). Conclusion: Cerebral oxygenation was not affected in the first day of life in preterm infants born with foetal vasculitis, while cerebral oxygenation in infants that later developed intraventricular haemorrhage was impaired....

  16. Neonatal cerebral oxygenation is not linked to foetal vasculitis and predicts intraventricular haemorrhage in preterm infants

    DEFF Research Database (Denmark)

    Sørensen, Line Carøe; Maroun, Lisa Leth; Borch, K.;

    2008-01-01

    AIM: The aim of the study was to compare the cerebral tissue oxygenation index (c-TOI) measured by near infrared spectroscopy (NIRS) in infants with and without foetal vasculitis. METHODS: Twenty-four infants with placental signs of a foetal inflammatory response (FIR), foetal vasculitis, were.......002). CONCLUSION: Cerebral oxygenation was not affected in the first day of life in preterm infants born with foetal vasculitis, while cerebral oxygenation in infants that later developed intraventricular haemorrhage was impaired Udgivelsesdato: 2008/11...

  17. Aflatoxin B1 transfer and metabolism in human placenta.

    Science.gov (United States)

    Partanen, Heidi A; El-Nezami, Hani S; Leppänen, Jukka M; Myllynen, Päivi K; Woodhouse, Heather J; Vähäkangas, Kirsi H

    2010-01-01

    Aflatoxin B1 (AFB1), a common dietary contaminant, is a major risk factor of hepatocellular carcinoma (HCC). Early onset of HCC in some countries in Africa and South-East Asia indicates the importance of early life exposure. Placenta is the primary route for various compounds, both nutrients and toxins, from the mother to the fetal circulation. Furthermore, placenta contains enzymes for xenobiotic metabolism. AFB1, AFB1-metabolites, and AFB1-albumin adducts have been detected in cord blood of babies after maternal exposure during pregnancy. However, the role that the placenta plays in the transfer and metabolism of AFB1 is not clear. In this study, placental transfer and metabolism of AFB1 were investigated in human placental perfusions and in in vitro studies. Eight human placentas were perfused with 0.5 or 5microM AFB1 for 2-4 h. In vitro incubations with placental microsomal and cytosolic proteins from eight additional placentas were also conducted. Our results from placental perfusions provide the first direct evidence of the actual transfer of AFB1 and its metabolism to aflatoxicol (AFL) by human placenta. In vitro incubations with placental cytosolic fraction confirmed the capacity of human placenta to form AFL. AFL was the only metabolite detected in both perfusions and in vitro incubations. Since AFL is less mutagenic, but putatively as carcinogenic as AFB1, the formation of AFL may not protect the fetus from the toxicity of AFB1.

  18. Placental Hypoxia During Early Pregnancy Causes Maternal Hypertension and Placental Insufficiency in the Hypoxic Guinea Pig Model.

    Science.gov (United States)

    Thompson, Loren P; Pence, Laramie; Pinkas, Gerald; Song, Hong; Telugu, Bhanu P

    2016-12-01

    Chronic placental hypoxia is one of the root causes of placental insufficiencies that result in pre-eclampsia and maternal hypertension. Chronic hypoxia causes disruption of trophoblast (TB) development, invasion into maternal decidua, and remodeling of maternal spiral arteries. The pregnant guinea pig shares several characteristics with humans such as hemomonochorial placenta, villous subplacenta, deep TB invasion, and remodeling of maternal arteries, and is an ideal animal model to study placental development. We hypothesized that chronic placental hypoxia of the pregnant guinea pig inhibits TB invasion and alters spiral artery remodeling. Time-mated pregnant guinea pigs were exposed to either normoxia (NMX) or three levels of hypoxia (HPX: 16%, 12%, or 10.5% O2) from 20 day gestation until midterm (39-40 days) or term (60-65 days). At term, HPX (10.5% O2) increased maternal arterial blood pressure (HPX 57.9 ± 2.3 vs. NMX 40.4 ± 2.3, P < 0.001), decreased fetal weight by 16.1% (P < 0.05), and increased both absolute and relative placenta weights by 10.1% and 31.8%, respectively (P < 0.05). At midterm, there was a significant increase in TB proliferation in HPX placentas as confirmed by increased PCNA and KRT7 staining and elevated ESX1 (TB marker) gene expression (P < 0.05). Additionally, quantitative image analysis revealed decreased invasion of maternal blood vessels by TB cells. In summary, this animal model of placental HPX identifies several aspects of abnormal placental development, including increased TB proliferation and decreased migration and invasion of TBs into the spiral arteries, the consequences of which are associated with maternal hypertension and fetal growth restriction.

  19. Deoxynivalenol transport across the human placental barrier

    DEFF Research Database (Denmark)

    Nielsen, Jeanette K S; Vikström, Anna C; Turner, Paul

    2011-01-01

    with the ex vivo dual perfusion model. The concentration of DON on the foetal side after 4h was about 21% of that on the maternal side at t=0. These results support the data from the BeWo monolayer model in respect to the transport rate of DON, and are consistent with our hypothesis of foetal exposure to DON...... revealed frequent human exposure. This study reports on DON transfer across the human placenta. Firstly, in vitro studies with the BeWo b30 clone were used as a rapid screening model showing transfer of DON through a stable confluent cell monolayer. Five term placentas were then used to study DON transfer...

  20. Deoxynivalenol transport across the human placental barrier.

    Science.gov (United States)

    Nielsen, Jeanette K S; Vikström, Anna C; Turner, Paul; Knudsen, Lisbeth E

    2011-09-01

    Deoxynivalenol (DON) is the most commonly detected mycotoxin contaminant of cereal crops and cereal based food products in temperate regions of the world. DON causes adverse health effects in animals, passes through to the foetus and causes foetal abnormalities in animals. Biomonitoring for DON has revealed frequent human exposure. This study reports on DON transfer across the human placenta. Firstly, in vitro studies with the BeWo b30 clone were used as a rapid screening model showing transfer of DON through a stable confluent cell monolayer. Five term placentas were then used to study DON transfer with the ex vivo dual perfusion model. The concentration of DON on the foetal side after 4h was about 21% of that on the maternal side at t=0. These results support the data from the BeWo monolayer model in respect to the transport rate of DON, and are consistent with our hypothesis of foetal exposure to DON during pregnancy.

  1. Performance Testing of Molten Regolith Electrolysis with Transfer of Molten Material for the Production of Oxygen and Metals on the Moon

    Science.gov (United States)

    Sibille, Laurent; Sadoway, Donald; Tripathy, Prabhat; Standish, Evan; Sirk, Aislinn; Melendez, Orlando; Stefanescu, Doru

    2010-01-01

    Previously, we have demonstrated the production of oxygen by electrolysis of molten regolith simulants at temperatures near 1600 C. Using an inert anode and suitable cathode, direct electrolysis (no supporting electrolyte) of the molten silicate is carried out, resulting in the production of molten metallic products at the cathode and oxygen gas at the anode. Initial direct measurements of current efficiency have confirmed that the process offer potential advantages of high oxygen production rates in a smaller footprint facility landed on the moon, with a minimum of consumables brought from Earth. We now report the results of a scale-up effort toward the goal of achieving production rates equivalent to 1 metric ton O2/year, a benchmark established for the support of a lunar base. We previously reported on the electrochemical behavior of the molten electrolyte as dependent on anode material, sweep rate and electrolyte composition in batches of 20-200g and at currents of less than 0.5 A. In this paper, we present the results of experiments performed at currents up to 10 Amperes) and in larger volumes of regolith simulant (500 g - 1 kg) for longer durations of electrolysis. The technical development of critical design components is described, including: inert anodes capable of passing continuous currents of several Amperes, container materials selection, direct gas analysis capability to determine the gas components co-evolving with oxygen. To allow a continuous process, a system has been designed and tested to enable the withdrawal of cathodically-reduced molten metals and spent molten oxide electrolyte. The performance of the withdrawal system is presented and critiqued. The design of the electrolytic cell and the configuration of the furnace were supported by modeling the thermal environment of the system in an effort to realize a balance between external heating and internal joule heating. We will discuss the impact these simulations and experimental findings have

  2. Catalytic transfer hydrogenation for stabilization of bio-oil oxygenates: reduction of p-cresol and furfural over bimetallic Ni-Cu catalysts using isopropanol

    Science.gov (United States)

    Transfer hydrogenation and hydrodeoxygenation of model bio-oil compounds (p-cresol and furfural) and bio-oils derived from biomass via traditional pyrolysis and tail-gas reactive pyrolysis (TGRP) were conducted. Mild batch reaction conditions were employed, using isopropanol as a hydrogen donor over...

  3. Genetic, maternal and placental factors in the association between birth weight and physical fitness: a longitudinal twin study.

    Directory of Open Access Journals (Sweden)

    Robbert N H Touwslager

    Full Text Available BACKGROUND: Adult cardiorespiratory fitness and muscle strength are related to all-cause and cardiovascular mortality. Both are possibly related to birth weight, but it is unclear what the importance is of genetic, maternal and placental factors in these associations. DESIGN: Peak oxygen uptake and measures of strength, flexibility and balance were obtained yearly during adolescence (10-18 years in 114 twin pairs in the Leuven Longitudinal Twin Study. Their birth weights had been collected prospectively within the East Flanders Prospective Twin Survey. RESULTS: We identified linear associations between birth weight and adolescent vertical jump (b = 1.96 cm per kg birth weight, P = 0.02, arm pull (b = 1.85 kg per kg birth weight P = 0.03 and flamingo balance (b = -1.82 attempts to stand one minute per kg birth weight, P = 0.03. Maximum oxygen uptake appeared to have a U-shaped association with birth weight (the smallest and largest children had the lowest uptake, P = 0.01, but this association was no longer significant after adjustment for parental BMI. Using the individual twin's deviation from his own twin pair's average birth weight, we found positive associations between birth weight and adolescent vertical jump (b = 3.49, P = 0.0007 and arm pull (b = 3.44, P = 0.02. Δ scores were calculated within the twin pairs as first born twin minus second born twin. Δ birth weight was associated with Δ vertical jump within MZ twin pairs only (b = 2.63, P = 0.009, which indicates importance of placental factors. CONCLUSIONS: We found evidence for an association between adolescent physical performance (strength, balance and possibly peak oxygen uptake and birth weight. The associations with vertical jump and arm pull were likely based on individual, more specifically placental (in the case of vertical jump factors. Our results should be viewed as hypothesis-generating and need confirmation, but potentially support preventive strategies to optimize

  4. Immunoinformatics of Placental Malaria Vaccine Development

    DEFF Research Database (Denmark)

    Jessen, Leon Eyrich

    Malaria is an infectious disease caused by a protozoan parasite of the genus Plasmodium, which is transferred by female Anopheles mosquitos. WHO estimates that in 2012 there were 207 million cases of malaria, of which 627,000 were fatal. People living in malaria-endemic areas, gradually acquire...

  5. Absence of Y chromosome in human placental site trophoblastic tumor.

    Science.gov (United States)

    Hui, Pei; Wang, Hanlin L; Chu, Peiguo; Yang, Bin; Huang, Jiaoti; Baergen, Rebecca N; Sklar, Jeffrey; Yang, Ximing J; Soslow, Robert A

    2007-10-01

    Placental site trophoblastic tumor is a neoplasm of extravillous intermediate trophoblast at the implantation site, preceded in the majority of cases by a female gestational event. Our pilot investigation suggested that the development of this tumor might require a paternally derived X chromosome and the absence of a Y chromosome. Twenty cases of placental site trophoblastic tumor were included in this study. Genotyping at 15 polymorphic loci and one sex determination locus was performed by multiplex PCR followed by capillary electrophoresis. X chromosome polymorphisms were determined by PCR amplification of exon 1 of the human androgen receptor gene using primers flanking the polymorphic CAG repeats within this region. Genotyping at 15 polymorphic loci was informative and paternal alleles were present in all tumors, confirming the trophoblastic origin of the tumors. The presence of an X chromosome and the absence of a Y chromosome were observed in all tumors. Among 13 cases in which analysis of the X chromosome polymorphism was informative, all but one demonstrated at least two X alleles and seven cases showed one identifiable paternal X allele. These results confirm a unique pathogenetic mechanism in placental site trophoblastic tumor, involving an exclusion of the Y chromosome from the genome and, therefore, a tumor arising from the trophectoderm of a female conceptus. As epigenetic regulations of imprinting during X chromosome inactivation are of significant biological implications, placental site trophoblastic tumor may provide an important model for studying the sex chromosome biology and the proliferative advantage conferred by the paternal X chromosome.

  6. Early studies of placental ultrastructure by electron microscopy

    DEFF Research Database (Denmark)

    Carter, A M; Enders, A C

    2016-01-01

    many other scientists to Washington University in St. Louis. Work on human placental ultrastructure was initiated at Cambridge and Kyoto whilst domestic animals were initially studied by Björkman in Stockholm and electron micrographs of bat placenta were published by Wimsatt of Cornell University...

  7. Placentation in dolphins from the Amazon River Basin

    DEFF Research Database (Denmark)

    da Silva, Vera M F; Carter, Anthony M; Ambrosio, Carlos E

    2007-01-01

    A recent reassessment of the phylogenetic affinities of cetaceans makes it timely to compare their placentation with that of the artiodactyls. We studied the placentae of two sympatric species of dolphin from the Amazon River Basin, representing two distinct families. The umbilical cord branched...

  8. Pathologic evaluation of normal and perfused term placental tissue

    DEFF Research Database (Denmark)

    Maroun, Lisa Leth; Mathiesen, Line; Hedegaard, Morten

    2014-01-01

    This study reports for the 1st time the incidence and interobserver variation of morphologic findings in a series of 34 term placentas from pregnancies with normal outcome used for perfusion studies. Histologic evaluation of placental tissue is challenging, especially when it comes to defining "n...

  9. Prevalence and predictors of placental malaria in human ...

    African Journals Online (AJOL)

    2016-02-16

    Feb 16, 2016 ... immunity that increase the risks to placental malaria infection. ... Materials and Methods: It was a longitudinal cohort study of pregnant women receiving ... their infants antenatally and peripartum. ... Plasmodium falciparum is stable. ..... immune responses during HIV‑malaria co‑infection in pregnancy. Trends.

  10. Oxidative stress and maternal obesity: feto-placental unit interaction.

    Science.gov (United States)

    Malti, N; Merzouk, H; Merzouk, S A; Loukidi, B; Karaouzene, N; Malti, A; Narce, M

    2014-06-01

    To determine oxidative stress markers in maternal obesity during pregnancy and to evaluate feto-placental unit interaction, especially predictors of fetal metabolic alterations. 40 obese pregnant women (prepregnancy BMI > 30 kg/m²) were compared to 50 control pregnant women. Maternal, cord blood and placenta samples were collected at delivery. Biochemical parameters (total cholesterol and triglycerides) and oxidative stress markers (malondialdehyde, carbonyl proteins, superoxide anion expressed as reduced Nitroblue Tetrazolium, nitric oxide expressed as nitrite, reduced glutathione, catalase, superoxide dismutase) were assayed by biochemical methods. Maternal, fetal and placental triglyceride levels were increased in obese group compared to control. Maternal malondialdehyde, carbonyl proteins, nitric oxide and superoxide anion levels were high while reduced glutathione concentrations and superoxide dismutase activity were low in obesity. In the placenta and in newborns of these obese mothers, variations of redox balance were also observed indicating high oxidative stress. Maternal and placental interaction constituted a strong predictor of fetal redox variations in obese pregnancies. Maternal obesity compromised placental metabolism and antioxidant status which strongly impacted fetal redox balance. Oxidative stress may be one of the key downstream mediators that initiate programming of the offspring. Maternal obesity is associated with metabolic alterations and dysregulation of redox balance in the mother-placenta - fetus unit. These perturbations could lead to maternal and fetal complications and should be carefully considered. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Polyaromatic compounds alter placental protein synthesis in pregnant rats

    Energy Technology Data Exchange (ETDEWEB)

    Shiverick, K.T.; Ogilvie, S.; Medrano, T. (Univ. of Florida, Gainesville (United States))

    1991-03-15

    The administration of the polyaromatic compounds {beta}-naphthoflavone ({beta}NF) and 3-methylcholanthrene (3MC) to pregnant rats during mid-gestation has been shown to produce marked feto-placental growth retardation. This study examined secretory protein synthesis in placental tissue from rats following administration of {beta}NF on gestation days (gd) 11-14 or 3MC on gd 12-14. Explants of placental basal zone tissue were cultured for 24 hours in serum-free medium in the presence of ({sup 3}H)leucine. Secreted proteins were analyzed by two-dimensional SDS-polyacrylamide gel electrophoresis followed by either fluorography or immunostaining. Total incorporation of ({sup 3}H)leucine into secreted proteins was not altered in BZ explants from {beta}NF or 3MC-treated animals. However a selective decrease was observed in ({sup 3}H)leucine incorporation into a major complex of proteins with apparent molecular weight of 25-30,000 and isoelectric point between 5.3 to 5.7. This group of proteins has been further identified as being related to rat pituitary growth hormone (GH) using N-terminal amino acid microsequencing of individual spots from 2-D SDS-PA gels. This is the first report that synthesis of GH-related proteins by rat placenta is decreased following {beta}NF and 3MC administration, a change which may underlie the feto-placental growth retardation associated with these polyaromatic compounds.

  12. Placentation in the Hottentot golden mole, Amblysomus hottentotus (Afrosoricida: Chrysochloridae)

    DEFF Research Database (Denmark)

    Jones, C J P; Carter, A M; Bennett, N C;

    2009-01-01

    The placentation of the Hottentot golden mole (Amblysomus hottentotus) has been examined using light and electron microscopy and lectin histochemistry of nine specimens at both mid and late gestation. The placentae were lobulated towards the allantoic surface and the lobules contained roughly par...

  13. Notch signalling in placental development and gestational diseases.

    Science.gov (United States)

    Haider, S; Pollheimer, J; Knöfler, M

    2017-01-16

    Activation of Notch signalling upon cell-cell contact of neighbouring cells controls a plethora of cellular processes such as stem cell maintenance, cell lineage determination, cell proliferation, and survival. Accumulating evidence suggests that the pathway also critically regulates these events during placental development and differentiation. Herein, we summarize our present knowledge about Notch signalling in murine and human placentation and discuss its potential role in the pathophysiology of gestational disorders. Studies in mice suggest that Notch controls trophectoderm formation, decidualization, placental branching morphogenesis and endovascular trophoblast invasion. In humans, the particular signalling cascade promotes formation of the extravillous trophoblast lineage and regulates trophoblast proliferation, survival and differentiation. Expression patterns as well as functional analyses indicate distinct roles of Notch receptors in different trophoblast subtypes. Altered effects of Notch signalling have been detected in choriocarcinoma cells, consistent with its role in cancer development and progression. Moreover, deregulation of Notch signalling components were observed in pregnancy disorders such as preeclampsia and fetal growth restriction. In summary, Notch plays fundamental roles in different developmental processes of the placenta. Abnormal signalling through this pathway could contribute to the pathogenesis of gestational diseases with aberrant placentation and trophoblast function.

  14. Oxygen atom transfer from {mu}-Oxo-bis[1,4,8,11,15,18,22,25-octakis(trifluoromethyl)ph-thalocya ninato]diiron(III) : evidence for an Fe(IV)=O intermediate.

    Energy Technology Data Exchange (ETDEWEB)

    Chen, M. J.; Rathke, J. W.; Chemical Engineering

    1998-01-01

    The dimeric [(FPc)Fe]2({mu}-O) (1) (FPc is the dianion of 1,4,8,11,15,18,22,25-octakis(trifluoromethyl)phthalocyanine) has been shown to transfer its -oxo atom quantitatively to trimethylphosphine and triphenylphosphine. In the case of triphenylphosphine a base such as 1-methylimidazole (MeIm) or pyridine (py) is needed to induce the oxygen atom transfer. The reaction of 1 with MeIm at -40 C and below gives [(MeIm)(FPc)Fe]2({mu}-O) (4), which disproportionates to give (MeIm)2(FPc)Fe (5) and (FPc)Fe=O (6) at higher temperatures. The oxo atom of 6 has been shown to transfer to triphenylphosphine. Similarly, 6 is generated by the disproportionation of 1 with py. It has also been generated by the oxidation of 1 with t-butyl hydroperoxide. [(FPc)Fe]2({mu}-O) catalyzes the oxidation of hydrocarbons by iodosylbenzene. With stilbenes, styrenes, cyclohexenes and butenes as substrates, both epoxidations and alkyl C-H bond oxidations have been observed. The epoxidation of cis-stilbene leads to a mixture of cis- and trans-stilbene oxides, indicating that epoxidation of cis-stilbene, and possibly other olefins as well, proceeds through a non-concerted mechanism.

  15. Brain size, life history, and metabolism at the marsupial/placental dichotomy.

    Science.gov (United States)

    Weisbecker, Vera; Goswami, Anjali

    2010-09-14

    The evolution of mammalian brain size is directly linked with the evolution of the brain's unique structure and performance. Both maternal life history investment traits and basal metabolic rate (BMR) correlate with relative brain size, but current hypotheses regarding the details of these relationships are based largely on placental mammals. Using encephalization quotients, partial correlation analyses, and bivariate regressions relating brain size to maternal investment times and BMR, we provide a direct quantitative comparison of brain size evolution in marsupials and placentals, whose reproduction and metabolism differ extensively. Our results show that the misconception that marsupials are systematically smaller-brained than placentals is driven by the inclusion of one large-brained placental clade, Primates. Marsupial and placental brain size partial correlations differ in that marsupials lack a partial correlation of BMR with brain size. This contradicts hypotheses stating that the maintenance of relatively larger brains requires higher BMRs. We suggest that a positive BMR-brain size correlation is a placental trait related to the intimate physiological contact between mother and offspring during gestation. Marsupials instead achieve brain sizes comparable to placentals through extended lactation. Comparison with avian brain evolution suggests that placental brain size should be constrained due to placentals' relative precociality, as has been hypothesized for precocial bird hatchlings. We propose that placentals circumvent this constraint because of their focus on gestation, as opposed to the marsupial emphasis on lactation. Marsupials represent a less constrained condition, demonstrating that hypotheses regarding placental brain size evolution cannot be generalized to all mammals.

  16. Using oxygen at home

    Science.gov (United States)

    Oxygen - home use; COPD - home oxygen; Chronic obstructive airways disease - home oxygen; Chronic obstructive lung disease - home oxygen; Chronic bronchitis - home oxygen; Emphysema - home oxygen; Chronic respiratory ...

  17. Gas transfer velocities for quantifying methane, oxygen and other gas fluxes through the air-water interface of wetlands with emergent vegetation

    Science.gov (United States)

    Poindexter, C.; Variano, E. A.

    2012-12-01

    Empirical models for the gas transfer velocity, k, in the ocean, lakes and rivers are fairly well established, but there are few data to predict k for wetlands. We have conducted experiments in a simulated emergent marsh in the laboratory to explore the relationship between k, wind shear and thermal convection. Now we identify the implications of these results for gas transfer in actual wetlands by (1) quantifying the range of wind conditions in emergent vegetation canopies and the range of thermal convection intensities in wetland water columns, and (2) describing the non-linear interaction of these two stirring forces over their relevant ranges in wetlands. We measured mean wind speeds and wind speed variance within the shearless region of a Schoenoplectus-Typha marsh canopy in the Sacramento-San Joaquin Delta (Northern California, USA). The mean wind speed within this region, , is significantly smaller than wind above the canopy. Based on our laboratory experiments, for calm or even average wind conditions in this emergent marsh k600 is only on the order 0.1 cm hr-1 (for neutrally or stably stratified water columns). We parameterize unstable thermal stratification and the resulting thermal convection using the heat flux through the air-water interface, q. We analyzed a water temperature record for the Schoenoplectus-Typha marsh to obtain a long-term heat flux record. We used these heat flux data along with short-term heat flux data from other wetlands in the literature to identify the range of the gas transfer velocity associated with thermal convection in wetlands. The typical range of heat fluxes through water columns shaded by closed emergent canopies (-200 W m-2 to +200 W m-2) yields k600 values of 0.5 - 2.5 cm hr-1 according to the model we developed in the laboratory. Thus for calm or average wind conditions, the gas transfer velocity associated with thermal convection is significantly larger than the gas transfer velocity associated with wind shear

  18. Does malaria affect placental development? Evidence from in vitro models.

    Directory of Open Access Journals (Sweden)

    Alexandra J Umbers

    Full Text Available BACKGROUND: Malaria in early pregnancy is difficult to study but has recently been associated with fetal growth restriction (FGR. The pathogenic mechanisms underlying malarial FGR are poorly characterized, but may include impaired placental development. We used in vitro methods that model migration and invasion of placental trophoblast into the uterine wall to investigate whether soluble factors released into maternal blood in malaria infection might impair placental development. Because trophoblast invasion is enhanced by a number of hormones and chemokines, and is inhibited by pro-inflammatory cytokines, many of which are dysregulated in malaria in pregnancy, we further compared concentrations of these factors in blood between malaria-infected and uninfected pregnancies. METHODOLOGY/PRINCIPAL FINDINGS: We measured trophoblast invasion, migration and viability in response to treatment with serum or plasma from two independent cohorts of Papua New Guinean women infected with Plasmodium falciparum or Plasmodium vivax in early pregnancy. Compared to uninfected women, serum and plasma from women with P. falciparum reduced trophoblast invasion (P = .06 and migration (P = .004. P. vivax infection did not alter trophoblast migration (P = .64. The P. falciparum-specific negative effect on placental development was independent of trophoblast viability, but associated with high-density infections. Serum from P. falciparum infected women tended to have lower levels of trophoblast invasion promoting hormones and factors and higher levels of invasion-inhibitory inflammatory factors. CONCLUSION/SIGNIFICANCE: We demonstrate that in vitro models of placental development can be adapted to indirectly study the impact of malaria in early pregnancy. These infections could result in impaired trophoblast invasion with reduced transformation of maternal spiral arteries due to maternal hormonal and inflammatory disturbances, which may contribute to FGR by

  19. In-vitro study of the effect of anti-hypertensive drugs on placental hormones and angiogenic proteins synthesis in pre-eclampsia.

    Directory of Open Access Journals (Sweden)

    Subrata Gangooly

    Full Text Available INTRODUCTION: Antihypertensive drugs lower the maternal blood pressure in pre-eclampsia (PE by direct or central vasodilatory mechanisms but little is known about the direct effects of these drugs on placental functions. OBJECTIVE: The aim of our study is to evaluate the effect of labetolol, hydralazine, α-methyldopa and pravastatin on the synthesis of placental hormonal and angiogenic proteins know to be altered in PE. DESIGN: Placental villous explants from late onset PE (n = 3 and normotensive controls (n = 6 were cultured for 3 days at 10 and 20% oxygen (O2 with variable doses anti-hypertensive drugs. The levels of activin A, inhibin A, human Chorionic Gonadotrophin (hCG, soluble fms-like tyrosine kinase-1 (sFlt-1 and soluble endoglin (sEng were measured in explant culture media on day 1, 2 and 3 using standard immunoassays. Data at day 1 and day 3 were compared. RESULTS: Spontaneous secretion of sEndoglin and sFlt-1 were higher (p < 0.05 in villous explants from PE pregnancies compared to controls. There was a significant time dependent decrease in the secretion of sFlt-1 and sEndoglin in PE cases, which was seen only for sFlt-1 in controls. In both PE cases and controls the placental protein secretions were not affected by varying doses of anti-hypertensive drugs or the different O2 concentration cultures, except for Activin, A which was significantly (p < 0.05 higher in controls at 10% O2. INTERPRETATION: Our findings suggest that the changes previously observed in maternal serum hormones and angiogenic proteins level after anti-hypertensive treatment in PE could be due to a systemic effect of the drugs on maternal blood pressure and circulation rather than a direct effect of these drugs on placental biosynthesis and/or secretion.

  20. Prenatal diagnosis of a placental infarction hematoma associated with fetal growth restriction, preeclampsia and fetal death: clinicopathological correlation.

    Science.gov (United States)

    Aurioles-Garibay, Alma; Hernandez-Andrade, Edgar; Romero, Roberto; Qureshi, Faisal; Ahn, Hyunyoung; Jacques, Suzanne M; Garcia, Maynor; Yeo, Lami; Hassan, Sonia S

    2014-01-01

    The lesion termed 'placental infarction hematoma' is associated with fetal death and adverse perinatal outcome. Such a lesion has been associated with a high risk of fetal death and abruption placentae. The fetal and placental hemodynamic changes associated with placental infarction hematoma have not been reported. This paper describes a case of early and severe growth restriction with preeclampsia, and progressive deterioration of the fetal and placental Doppler parameters in the presence of a placental infarction hematoma.

  1. Effects of transcutaneous electrical nerve stimulation on fetal and placental development in an experimental model of placental insufficiency.

    Science.gov (United States)

    Guimarães, Camila S O; Gomes, Bruno B F; Oliveira, Rafael A; Yamamoto, Leandro R; Rocha, Laura P; Glória, Maria A; Machado, Juliana R; Câmara, Niels O S; Reis, Marlene A; Corrêa, Rosana R M

    2016-01-01

    To elucidate the effects of transcutaneous electrical nerve stimulation (TENS) in pregnancies with placental insufficiency. Pregnant rats were subjected to uterine artery ligation and to TENS according to the following groups: ligated stimulated (LS); ligated non-stimulated (LN), control stimulated (CS); and control non-stimulated (CN). Fetal external measurements, such as crown-rump length (CRL), fronto-occipital distance (FOD), thoracic ventral-dorsal (TVDD) and abdominal ventral-dorsal (AVDD) distances were analyzed together with the area occupied by fetal internal organs. Glucose transporter 1 (GLUT-1) expression was evaluated by immunohistochemistry in fetal organs. Thickness of junctional, labyrinth and intermediate placental zones was analyzed by morphometric evaluation in HE-stained slides, and placental hypoxia-inducible factor 1 alfa expression was measured by real-time polymerase chain reaction. In LN and CS groups compared to the CN group, CRL was reduced (27.51/28.95 versus 30.16 mm), as well as FOD (6.63/6.63 versus 7.36 mm), AVDD (7.38/8.00 versus 8.61 mm) and TVDD (6.46/6.87 versus 7.23 mm). Brain GLUT-1 expression was higher in LS (1.3%) and CS (1.8%). The area occupied by placental vessels in the labyrinth zone (29.67 ± 3.51 versus 20.83 ± 7.63) and intermediate zone (26.46 ± 10.21 versus 10.86 ± 8.94) was larger in the LS group than in the LN group. Our results suggest a negative effect of TENS on placental development, thus compromising the maintenance of adequate blood flow to the fetus.

  2. Modeling Oxygen Transport in the Human Placenta

    Science.gov (United States)

    Serov, Alexander; Filoche, Marcel; Salafia, Carolyn; Grebenkov, Denis

    Efficient functioning of the human placenta is crucial for the favorable pregnancy outcome. We construct a 3D model of oxygen transport in the placenta based on its histological cross-sections. The model accounts for both diffusion and convention of oxygen in the intervillous space and allows one to estimate oxygen uptake of a placentone. We demonstrate the existence of an optimal villi density maximizing the uptake and explain it as a trade-off between the incoming oxygen flow and the absorbing villous surface. Calculations performed for arbitrary shapes of fetal villi show that only two geometrical characteristics - villi density and the effective villi radius - are required to predict fetal oxygen uptake. Two combinations of physiological parameters that determine oxygen uptake are also identified: maximal oxygen inflow of a placentone and the Damköhler number. An automatic image analysis method is developed and applied to 22 healthy placental cross-sections demonstrating that villi density of a healthy human placenta lies within 10% of the optimal value, while overall geometry efficiency is rather low (around 30-40%). In a perspective, the model can constitute the base of a reliable tool of post partum oxygen exchange efficiency assessment in the human placenta. Also affiliated with Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA 90095, USA.

  3. Elevated Adenosine Induces Placental DNA Hypomethylation Independent of A2B Receptor Signaling in Preeclampsia.

    Science.gov (United States)

    Huang, Aji; Wu, Hongyu; Iriyama, Takayuki; Zhang, Yujin; Sun, Kaiqi; Song, Anren; Liu, Hong; Peng, Zhangzhe; Tang, Lili; Lee, Minjung; Huang, Yun; Ni, Xin; Kellems, Rodney E; Xia, Yang

    2017-07-01

    Preeclampsia is a prevalent pregnancy hypertensive disease with both maternal and fetal morbidity and mortality. Emerging evidence indicates that global placental DNA hypomethylation is observed in patients with preeclampsia and is linked to altered gene expression and disease development. However, the molecular basis underlying placental epigenetic changes in preeclampsia remains unclear. Using 2 independent experimental models of preeclampsia, adenosine deaminase-deficient mice and a pathogenic autoantibody-induced mouse model of preeclampsia, we demonstrate that elevated placental adenosine not only induces hallmark features of preeclampsia but also causes placental DNA hypomethylation. The use of genetic approaches to express an adenosine deaminase minigene specifically in placentas, or adenosine deaminase enzyme replacement therapy, restored placental adenosine to normal levels, attenuated preeclampsia features, and abolished placental DNA hypomethylation in adenosine deaminase-deficient mice. Genetic deletion of CD73 (an ectonucleotidase that converts AMP to adenosine) prevented the elevation of placental adenosine in the autoantibody-induced preeclampsia mouse model and ameliorated preeclampsia features and placental DNA hypomethylation. Immunohistochemical studies revealed that elevated placental adenosine-mediated DNA hypomethylation predominantly occurs in spongiotrophoblasts and labyrinthine trophoblasts and that this effect is independent of A2B adenosine receptor activation in both preeclampsia models. Extending our mouse findings to humans, we used cultured human trophoblasts to demonstrate that adenosine functions intracellularly and induces DNA hypomethylation without A2B adenosine receptor activation. Altogether, both mouse and human studies reveal novel mechanisms underlying placental DNA hypomethylation and potential therapeutic approaches for preeclampsia. © 2017 American Heart Association, Inc.

  4. [Apneic oxygenation].

    Science.gov (United States)

    Alekseev, A V; Vyzhigina, M A; Parshin, V D; Fedorov, D S

    2013-01-01

    Recent technological advances in thoracic and tracheal surgery make the anaesthesiologist use different respiratory techniques during the operation. Apneic oxygenation is a one of alternative techniques. This method is relatively easy in use, does not require special expensive equipment and is the only possible technique in several clinical situations when other respiratory methods are undesirable or cannot be used. However there is no enough information about apneic oxygenation in Russian. This article reviews publications about apneic oxygenation. The review deals with experiments on diffusion respiration in animals, physiological changes during apneic oxygenation in man and defines clinical cases when apneic oxygenation can be used.

  5. Transplacental transfer of monomethyl phthalate and mono(2-ethylhexyl) phthalate in a human placenta perfusion system

    DEFF Research Database (Denmark)

    Mose, Tina; Knudsen, Lisbeth E; Hedegaard, Morten;

    2007-01-01

    and after perfusion were also analyzed. Placentas were obtained immediately after elective cesarean section and dually perfused in a recirculation system. mMP or mEHP was added to maternal perfusion medium to obtain concentrations at 10 and 25 microg/L, respectively. The placental transfer was followed...... plasma samples. mMP and possibly other short-chained phthalate monoesters in maternal blood can cross the placenta by slow transfer, whereas the results indicate no placental transfer of mEHP. Further studies are recommended....

  6. Ultrasound assessment of placental function: the effectiveness of placental biometry in a low-risk population as a predictor of a small for gestational age neonate.

    LENUS (Irish Health Repository)

    McGinty, Patricia

    2012-07-01

    The aims of the study were to establish reference ranges for placental length and thickness in a low-risk obstetric population and to assess the likelihood of a small for gestational age (SGA) neonate on the basis of placental length at 18-24 weeks\\' gestation.

  7. Second-Trimester 3-Dimensional Placental Sonography as a Predictor of Small-for-Gestational-Age Birth Weight.

    Science.gov (United States)

    Quant, Hayley S; Sammel, Mary D; Parry, Samuel; Schwartz, Nadav

    2016-08-01

    We previously reported the association between first-trimester 3-dimensional (3D) placental measurements and small-for-gestational-age (SGA) neonates. In this study, we sought to determine whether second-trimester measurements further contribute to the antenatal detection of SGA and preeclampsia. We prospectively collected 3D sonographic volume sets and uterine artery pulsatility indices of singleton pregnancies at 18 to 24 weeks. Placental volume, placental quotient (placental volume/gestational age), mean placental diameter and chorionic diameter, placental morphologic index (mean placental diameter/placental quotient), placental chorionic index (mean chorionic diameter/placental quotient), and placental growth (volume per week) were assessed and evaluated as predictors of SGA and preeclampsia as a composite and alone. Of 373 pregnancies, the composite outcome occurred in 67 (18.0%): 36 (9.7%) manifested SGA alone; 27 (7.2%) developed preeclampsia alone, and 4 (1.1%) developed both. The placental volume, placental quotient, mean placental diameter, mean chorionic diameter, and volume per week were significantly smaller, whereas the placental morphologic index and chorionic index were significantly larger in pregnancies with the composite outcome (P < .01). Further analyses revealed that the significant associations with placental parameters were limited to the SGA outcome. Each placental measure remained significantly associated with SGA after adjusting for confounders. The mean uterine artery pulsatility index was not associated with either outcome. Placental parameters were moderately predictive of SGA, with adjusted areas under the curve ranging from 0.72 to 0.76. Sensitivity for detection of SGA ranged from 32.5% to 45.0%, with positive predictive values ranging from 17.3% to 22.7%. Second-trimester 3D placental measurements can identify pregnancies at risk of SGA. However, there appears to be no significant improvement compared to those obtained in the first

  8. Toxicokinetics of the food-toxin IQ in human placental perfusion is not affected by ABCG2 or xenobiotic metabolism

    DEFF Research Database (Denmark)

    Immonen, E; Kummu, M; Petsalo, A

    2010-01-01

    Metabolizing enzymes and transporters affect toxicokinetics of foreign compounds (e.g. drugs and carcinogens) in human placenta. The heterocyclic amine, 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) is a food-borne carcinogen being metabolically activated by cytochrome P450 (CYP) enzymes, especially...... by CYP1A1/2. IQ is also a substrate for ABCG2 transporter. Placental transfer of (14)C-IQ was evaluated in 4-6 h ex vivo human placental perfusions in Finland and Denmark. In Finland placentas were perfused with (14)C-IQ alone (0.5 muM, n = 6) or in combination with GF120918 (inhibitor of ABCG2, 1 muM, n...... = 6) or Ko143 (specific inhibitor of ABCG2, 2 muM, n = 4) to study the role of ABCG2 inhibition in transfer while in Denmark perfusions were performed with (14)C-IQ alone. Critical parameters (leak from fetal to maternal circulation, pH values, blood gases, glucose consumption, the production of h...

  9. Massive dysregulation of genes involved in cell signaling and placental development in cloned cattle conceptus and maternal endometrium.

    Science.gov (United States)

    Biase, Fernando H; Rabel, Chanaka; Guillomot, Michel; Hue, Isabelle; Andropolis, Kalista; Olmstead, Colleen A; Oliveira, Rosane; Wallace, Richard; Le Bourhis, Daniel; Richard, Christophe; Campion, Evelyne; Chaulot-Talmon, Aurélie; Giraud-Delville, Corinne; Taghouti, Géraldine; Jammes, Hélène; Renard, Jean-Paul; Sandra, Olivier; Lewin, Harris A

    2016-12-20

    A major unresolved issue in the cloning of mammals by somatic cell nuclear transfer (SCNT) is the mechanism by which the process fails after embryos are transferred to the uterus of recipients before or during the implantation window. We investigated this problem by using RNA sequencing (RNA-seq) to compare the transcriptomes in cattle conceptuses produced by SCNT and artificial insemination (AI) at day (d) 18 (preimplantation) and d 34 (postimplantation) of gestation. In addition, endometrium was profiled to identify the communication pathways that might be affected by the presence of a cloned conceptus, ultimately leading to mortality before or during the implantation window. At d 18, the effects on the transcriptome associated with SCNT were massive, involving more than 5,000 differentially expressed genes (DEGs). Among them are 121 genes that have embryonic lethal phenotypes in mice, cause defects in trophoblast and placental development, and/or affect conceptus survival in mice. In endometria at d 18, genes were affected by the presence of a cloned conceptus, whereas at d 34, ∼36% and genes were differentially expressed in intercaruncular and caruncular tissues, respectively. Functional analysis of DEGs in placental and endometrial tissues suggests a major disruption of signaling between the cloned conceptus and the endometrium, particularly the intercaruncular tissue. Our results support a "bottleneck" model for cloned conceptus survival during the periimplantation period determined by gene expression levels in extraembryonic tissues and the endometrial response to altered signaling from clones.

  10. The role of blood flow distribution in the regulation of cerebral oxygen availability in fetal growth restriction.

    Science.gov (United States)

    Luria, Oded; Bar, Jacob; Kovo, Michal; Malinger, Gustavo; Golan, Abraham; Barnea, Ofer

    2012-04-01

    Fetal growth restriction (FGR) elicits hemodynamic compensatory mechanisms in the fetal circulation. These mechanisms are complex and their effect on the cerebral oxygen availability is not fully understood. To quantify the contribution of each compensatory mechanism to the fetal cerebral oxygen availability, a mathematical model of the fetal circulation was developed. The model was based on cardiac-output distribution in the fetal circulation. The compensatory mechanisms of FGR were simulated and their effects on cerebral oxygen availability were analyzed. The mathematical analysis included the effects of cerebral vasodilation, placental resistance to blood flow, degree of blood shunting by the ductus venosus and the effect of maternal-originated placental insufficiency. The model indicated a unimodal dependency between placental blood flow and cerebral oxygen availability. Optimal cerebral oxygen availability was achieved when the placental blood flow was mildly reduced compared to the normal flow. This optimal ratio was found to increase as the hypoxic state of FGR worsens. The model indicated that cerebral oxygen availability is increasingly dependent on the cardiac output distribution as the fetus gains weight. Copyright © 2011 IPEM. Published by Elsevier Ltd. All rights reserved.

  11. Oxidized/reduced graphene nanoribbons facilitate charge transfer to the Fe(CN)63-/Fe(CN)64- redox couple and towards oxygen reduction

    Science.gov (United States)

    de Lima, Fábio; Maia, Gilberto

    2015-03-01

    This study investigated the synthesis of graphene oxide nanoribbons (GONRs) and graphene nanoribbons (GNRs) from multiwalled carbon nanotubes (MWCNTs), and the behavior of thin films of MWCNTs, GONRs, and GNRs on a glassy carbon surface in the presence of two redox probes (Fe(CN)63-/Fe(CN)64- and O2) employing cyclic voltammetry, electrochemical impedance spectroscopy, and hydrodynamic voltammetry (HV) as a simple procedure for characterizing these films. The feasibility of using these electrochemical techniques for this purpose opens up the possibility of applying them to biosensors and electrocatalysts using surface-supported MWCNT, GONR, and GNR materials. GNR1 resembles an internodal segment of bamboo cut lengthwise, with a shallow troughing at its center, while GNR2 resembles stacked ribbons, each ~16 nm wide, with points of structural damage and points of four-ribbon connection measuring 60 nm or wider, sufficiently catalytic for the oxygen reduction reaction to occur, unlike the other modified electrodes investigated in acidic, 0.1 M KH2PO4 (pH 7.0), and 0.1 M KOH solutions (HV results). Transmission electron microscopy and thermogravimetric analysis were employed to characterize the MWCNTs, GONRs, and GNRs.This study investigated the synthesis of graphene oxide nanoribbons (GONRs) and graphene nanoribbons (GNRs) from multiwalled carbon nanotubes (MWCNTs), and the behavior of thin films of MWCNTs, GONRs, and GNRs on a glassy carbon surface in the presence of two redox probes (Fe(CN)63-/Fe(CN)64- and O2) employing cyclic voltammetry, electrochemical impedance spectroscopy, and hydrodynamic voltammetry (HV) as a simple procedure for characterizing these films. The feasibility of using these electrochemical techniques for this purpose opens up the possibility of applying them to biosensors and electrocatalysts using surface-supported MWCNT, GONR, and GNR materials. GNR1 resembles an internodal segment of bamboo cut lengthwise, with a shallow troughing at its

  12. Parvovirus infection: an immunohistochemical study using fetal and placental tissue.

    Science.gov (United States)

    Li, Jing Jing; Henwood, Tony; Van Hal, Sebastian; Charlton, Amanda

    2015-01-01

    Parvovirus B19 infection causes 5% to 15% of cases of nonimmune hydrops fetalis. The aim of our study was to evaluate the use of immunohistochemistry in diagnosing parvovirus infection in fetal and placental tissue during routine fetal and perinatal autopsies. Histology slides of 20 cases of confirmed parvovirus infection were reviewed, and immunohistochemistry was applied to selected blocks of fetal and placental tissue. Immunohistochemistry was positive in all 20 cases, and histologic viral inclusions were seen in 19 cases. Immunohistochemical staining was closely correlated with histology and was more sensitive than histology in detecting virally infected cells, especially in autolyzed tissue. All cases also had confirmatory evidence of parvovirus infection by polymerase chain reaction of fetal liver and positive maternal serology, where it was available. We conclude that parvovirus immunohistochemistry is a reliable method for diagnosing parvovirus infection, especially in autolyzed tissue where histologic assessment may be suboptimal.

  13. Placental lactogen levels as guide to outcome of threatened abortion.

    Science.gov (United States)

    Niven, P A; Landon, J; Chard, T

    1972-09-30

    The clinical value has been assessed of circulating placental lactogen levels as a pointer to the outcome in a patient with vaginal bleeding in early pregnancy. By using a semiautomated radioimmunoassay the normal range of values for the first and second trimesters has been established. In patients admitted with vaginal bleeding after the eighth week of gestation estimation of plasma human placental lactogen showed that patients with low levels were those in whom the abortion was completed during the first admission. Women whose pregnancies continued normally or who aborted after their first discharge from hospital had normal levels. In a small group sampled before the onset of bleeding but who later aborted the mean levels were lower than normal. This simple and inexpensive test can indicate those women in whom abortion is inevitable and could be used to reduce substantially the length of hospital stay in this common complication of early pregnancy.

  14. Placental extracellular vesicles and feto-maternal communication.

    Science.gov (United States)

    Tong, M; Chamley, L W

    2015-01-29

    The human placenta is an anatomically unique structure that extrudes a variety of extracellular vesicles into the maternal blood (including syncytial nuclear aggregates, microvesicles, and nanovesicles). Large quantities of extracellular vesicles are produced by the placenta in both healthy and diseased pregnancies. Since their first description more than 120 years ago, placental extracellular vesicles are only now being recognized as important carriers for proteins, lipids, and nucleic acids, which may play a crucial role in feto-maternal communication. Here, we summarize the current literature on the cargos of placental extracellular vesicles and the known effects of such vesicles on maternal cells/systems, especially those of the maternal immune and vascular systems. Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.

  15. Radioimmunoassay of human placental protein 14 (PP14)

    Energy Technology Data Exchange (ETDEWEB)

    Bolton, A.E.; Stoker, R.J. (North East London Polytechnic (UK)); Chapman, M.G.; Wass, D. (Queen Charlotte' s Maternity Hospital, London (UK)); Andrew, C.E. (Edgware General Hospital (UK)); Bohn, H. (Behringwerke AG, Marburg/Lahn (Germany, F.R.). Research Labs.)

    1983-12-30

    The development and validation of a radioimmunoassay for the measurement of human placental protein 14 in maternal serum is described. The mean concentration of this protein in serum from 22 normal pregnant women showed a decline during the third trimester from 120 ..mu..g/l at 27 weeks gestation to 65 ..mu..g/l at term. Serum samples from 16 patients with intra-uterine growth retardation tended to contain lower concentrations of placental protein 14, these results reaching significance at weeks 36-38 of gestation. Of seven patients with pre-eclampsia from whom two or more blood samples were taken, four showed increases in concentration of this protein as pregnancy proceeded, compared with the normal pattern of decreasing values.

  16. Triazole fungicide tebuconazole disrupts human placental trophoblast cell functions

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jinghua [Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Education, Zhejiang University, Hangzhou 310058 (China); Zhang, Jianyun [Research Center for Air Pollution and Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Li, Feixue [Zhejiang Key Laboratory of Organ Development and Regeneration, Institute of Developmental and Regenerative Biology, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036 (China); Liu, Jing, E-mail: jliue@zju.edu.cn [Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Education, Zhejiang University, Hangzhou 310058 (China); Research Center for Air Pollution and Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China)

    2016-05-05

    Highlights: • Tebuconazole (TEB) inhibited the proliferation of human placental trophoblasts. • TEB changed cell cycle distribution of G1 and G2 phases of trophoblasts. • TEB induced apoptosis of trophoblasts via mitochondrial pathway. • TEB decreased the invasive and migratory capacities of trophoblasts. • TEB altered the mRNA levels of key regulatory genes in trophoblasts - Abstract: Triazole fungicides are one of the top ten classes of current-use pesticides. Although exposure to triazole fungicides is associated with reproductive toxicity in mammals, limited information is available regarding the effects of triazole fungicides on human placental trophoblast function. Tebuconazole (TEB) is a common triazole fungicide that has been extensively used for fungi control. In this work, we showed that TEB could reduce cell viability, disturb normal cell cycle distribution and induce apoptosis of human placental trophoblast cell line HTR-8/SVneo (HTR-8). Bcl-2 protein expression decreased and the level of Bax protein increased after TEB treatment in HTR-8 cells. The results demonstrated that this fungicide induced apoptosis of trophoblast cells via mitochondrial pathway. Importantly, we found that the invasive and migratory capacities of HTR-8 cells decreased significantly after TEB administr