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A barreira placentária em cães (Canis familiaris, Linnaeus, 1758): fluxo sanguíneo materno-fetal; The placental barrier in dogs (Canis familiaris, Linnaeus, 1758): maternal-fetal blood flow

Ambrósio, Carlos Eduardo
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 09/06/2004 Português
Relevância na Pesquisa
46.23%
Este estudo define a inter-relação microvascular materno-fetal e o desenvolvimento dos hematomas placentários durante diferentes períodos gestacionais em cães SRD. Placentas de 20, 35, 45 e 55 dias da prenhez foram perfundidas e fixadas para a investigação histológica e confecção de moldes vasculares, injetados com Mercox, e submetidos a corrosão para análise ao microscópio eletrônico de varredura. Os componentes fetais da placenta endoteliocorial e zonária anular do cão são irrigadas por dois ramos arteriais do cordão umbilical, um endereçado à cinta placentária, e outro ao hematoma marginal. Da artéria principal central, originam-se colaterais destinados às lamelas e vilos do labirinto no sentido feto-uterino. O desenvolvimento lamelar mostrou-se progressivo com o avançar da prenhez. Os complexos capilares na periferia dos vilos têm a forma de tufos de pêlos, cujos capilares são contínuos com o sistema venoso. Da artéria hematomal organizam-se os lóbulos microvasculares circulares, que aparecem no septo ou barreiras entre o hematoma marginal e o labirinto. Os capilares placentários maternos dispõem-se de maneira a cruzar os capilares fetais. Conseqüentemente, o fluxo sangüíneo placentário de cães Sem Raça Definida é caracterizado por um tipo de sentido único de corrente cruzada simples. O desenvolvimento dos hematomas marginais foi quantificado por morfometria. Os primeiros traços dos hematomas apareceram entre o 18º a 20º dia da prenhez como áreas hemorrágicas...

Identification of pro-thymocytes in murine fetal blood: T lineage commitment can precede thymus colonization.

Rodewald, H R; Kretzschmar, K; Takeda, S; Hohl, C; Dessing, M
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 15/09/1994 Português
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46.3%
Phenotype and commitment of thymus-colonizing precursors are unknown. Here we report the identification of T lineage-committed precursors (designated prothymocytes) in murine fetal blood at day 15.5 of development. Fetal blood pro-thymocytes are Thy-1+c-kit(low)CD3- in contrast to fetal blood-derived pluripotent hematopoietic progenitors which are Thy-1-c-kit+. Upon transfer into the thymus, fetal blood pro-thymocytes generate a single wave of CD4+CD8+ thymocytes and subsequently mature TCR alpha beta+ peripheral T cells. However, fetal blood pro-thymocytes lack multipotent progenitor potential since they fail to reconstitute B lymphocytes and myeloid and erythroid lineages. In contrast, T and B lymphocytes as well as myeloid and erythroid lineages are reconstituted from fetal blood-derived pluripotent progenitors. Pro-thymocytes are equally present in peripheral blood of athymic fetal mice, suggesting that this novel precursor population is T lineage-committed prior to thymus colonization and represents the earliest T lineage precursor identified.

Method of Breech Management Incorporating Use of Fetal Blood Sampling

Eliot, B. W.; Hill, J. G.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 23/12/1972 Português
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46.21%
We have developed a method of breech management based on the use of fetal blood sampling. Twenty-five cases were studied throughout labour, and fetal blood samples taken throughout the first and second stages. These showed that the Apgar score at one minute correlated closely with the fetal pH just before delivery. We believe that cord compression is an important variable factor which can be assessed only by fetal blood sampling. If this shows that fetal anoxia is becoming severe then immediate delivery is mandatory.

Uterine and fetal blood flow indexes and fetal growth assessment after chronic estrogen suppression in the second half of baboon pregnancy

Aberdeen, Graham W.; Baschat, Ahmet A.; Harman, Chris R.; Weiner, Carl P.; Langenberg, Patricia W.; Pepe, Gerald J.; Albrecht, Eugene D.
Fonte: American Physiological Society Publicador: American Physiological Society
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.28%
Although estrogen regulates important aspects of maternal cardiovascular physiology, the role of estrogen on uteroplacental and fetal blood flow is incompletely understood. This study tested the hypothesis that chronically suppressing endogenous estrogen production during the second half of baboon pregnancy alters uterine and fetal blood flow dynamics assessed by ultrasonography. Pregnant baboons were untreated or treated daily with the aromatase inhibitor letrozole or letrozole plus estradiol on days 100–160 of gestation (term = 184 days). Blood flow dynamics were determined by Doppler ultrasonography on day 60 and longitudinally between days 110 and 160 of gestation. Letrozole decreased maternal serum estradiol and estrone concentrations by 95% (P < 0.001). Fetal growth biometrical parameters increased (P < 0.001) between days 110 and 160 of gestation and were similar in untreated and letrozole-treated animals. Uterine, umbilical, and fetal middle cerebral artery pulsatility index and resistance index declined (P < 0.01) by 30–50% and uterine artery volume flow increased sixfold (P < 0.001) between days 60 and 160, but values were similar in untreated, letrozole-treated, and letrozole plus estradiol-treated baboons. Thus uterine and fetal artery blood flow indexes...

Discriminative imaging of maternal and fetal blood flow within the placenta using ultrafast ultrasound

Osmanski, Bruno-Felix; Lecarpentier, Edouard; Montaldo, Gabriel; Tsatsaris, Vassilis; Chavatte-Palmer, Pascale; Tanter, Mickael
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 16/09/2015 Português
Relevância na Pesquisa
46.21%
Being able to map accurately placental blood flow in clinics could have major implications in the diagnosis and follow-up of pregnancy complications such as intrauterine growth restriction (IUGR). Moreover, the impact of such an imaging modality for a better diagnosis of placental dysfunction would require to solve the unsolved problem of discriminating the strongly intricated maternal and fetal vascular networks. However, no current imaging modality allows both to achieve sufficient sensitivity and selectivity to tell these entangled flows apart. Although ultrasound imaging would be the clinical modality of choice for such a problem, conventional Doppler echography both lacks of sensibility to detect and map the placenta microvascularization and a concept to discriminate both entangled flows. In this work, we propose to use an ultrafast Doppler imaging approach both to map with an enhanced sensitivity the small vessels of the placenta (~100 μm) and to assess the variation of the Doppler frequency simultaneously in all pixels of the image within a cardiac cycle. This approach is evaluated in vivo in the placenta of pregnant rabbits: By studying the local flow pulsatility pixel per pixel, it becomes possible to separate maternal and fetal blood in 2D from their pulsatile behavior. Significance Statement: The in vivo ability to image and discriminate maternal and fetal blood flow within the placenta is an unsolved problem which could improve the diagnosis of pregnancy complications such as intrauterine growth restriction or preeclampsia. To date...

Haematopoietic indicators of fetal metabolic acidosis

Spencer, M.; Khong, T.; Matthews, B.; MacLennan, A.
Fonte: Blackwell Publishing Asia Publicador: Blackwell Publishing Asia
Tipo: Artigo de Revista Científica
Publicado em //2000 Português
Relevância na Pesquisa
46.23%
We aimed to study the haematopoietic response in normal and acidotic deliveries following vaginal and abdominal delivery and to compare this to the surrogate markers of perinatal acidosis. Blood gas analyses, complete blood pictures and erythropoietin assays were performed on umbilical or early neonatal blood samples. Placental sections were examined for the presence of nucleated red blood cells. Perinatal clinical risk factors and major neonatal outcomes were collected. The control population was 78 deliveries where the cord arterial pH was > 7.10. Controls born after labour were compared to those born prior to the onset of labour and to 14 acidotic infants born after labour. Nucleated red blood cells did not increase with labour in the control groups but were significantly higher (p < 0.05) in the acidotic group. Erythropoietin did not significantly change with either labour or acidosis. The predictive values from nucleated red blood cell counts were higher than those from low Apgar scores, atypical cardiotocograph traces, meconium-stained amniotic fluid, erythropoietin and the presence of nucleated red blood cells in placental sections. Nucleated red blood cell counts may be a useful surrogate marker of acidosis where blood gas analysis is unavailable. Further studies are required to examine the timing of the increase of erythropoiesis to help define the onset of the stimulus.

Determinants of fetal leptin synthesis, fat mass, and circulating leptin concentrations in well-nourished ewes in late pregnancy

Muhlhausler, B.; Roberts, C.; Yuen, B.; Marrocco, E.; Budge, H.; Symonds, M.; McFarlane, J.; Kauter, K.; Stagg, P.; Pearse, J.; McMillen, I.
Fonte: Endocrine Soc Publicador: Endocrine Soc
Tipo: Artigo de Revista Científica
Publicado em //2003 Português
Relevância na Pesquisa
46.19%
We have investigated the factors regulating leptin synthesis, fat deposition, and circulating leptin concentrations in fetuses of well nourished ewes in late pregnancy. Vascular catheters were surgically inserted in 17 pregnant ewes and their fetuses at 103–120 d gestation (term = 147 ± 3 d). Ewes were fed a diet providing either 100% (control; n = 9) or approximately 155% (well fed; n = 8) of the maintenance energy requirements and fetal perirenal and interscapular fat depots were collected at 139–141 d gestation. There was a significant relationship between the relative mass of fetal unilocular fat and fetal glucose (relative mass of unilocular fat, 1.14; fetal glucose, +0.16; r = 0.50; P < 0.04; n = 17), but not insulin, concentrations in the control and well-fed groups. In contrast to the controls, there was a positive relationship between the relative abundance of leptin mRNA and fetal insulin, but not glucose, concentrations in fetal perirenal adipose tissue in the well-fed group. A moderate increase in maternal nutrition also resulted in a strong reciprocal relationship between uncoupling protein 1 and leptin expression in fetal perirenal adipose tissue in late gestation (well-fed group: uncoupling protein 1 mRNA:18S rRNA...

Treatment of underfed pigs with GH throughout the second quarter of pregnancy increases fetal growth

Gatford, K.; Owens, J.; Campbell, R.; Boyce, J.; Grant, P.; De Blasio, M.; Owens, P.
Fonte: Soc Endocrinology Publicador: Soc Endocrinology
Tipo: Artigo de Revista Científica
Publicado em //2000 Português
Relevância na Pesquisa
46.2%
Circulating growth hormone (GH) concentrations increase in pregnancy and administration of GH during early-mid pregnancy increases fetal growth in well-fed pigs. To determine whether increased maternal GH could promote fetal growth when feed availability is restricted, fifteen cross-bred primiparous sows (gilts) were fed at approximately 30% of ad libitum intake, from mating onwards and were injected daily i.m. with recombinant porcine GH (pGH) at doses of 0, 13.4+/-0.3 and 25.6+/-0.5 microg/kg live weight from day 25 to day 51 of pregnancy (term approximately 115 days). Treatment with pGH increased maternal backfat loss between day 25 and day 51 of pregnancy, and increased maternal plasma IGF-I concentrations measured at day 51 of pregnancy. Fetal body weight, length and skull width at day 51 of pregnancy were increased by maternal treatment with pGH. Fetal plasma glucose concentrations were increased and maternal/fetal plasma glucose concentration gradients were decreased by maternal pGH treatment at 13.4, but not 25.6 microg/kg.day. Fetal plasma concentrations of urea were decreased by both levels of pGH treatment. Overall, fetal weight was negatively correlated with fetal plasma concentrations of urea, positively correlated with maternal plasma alpha-amino nitrogen concentrations and unrelated to glucose concentrations in either maternal or fetal plasma. This suggests that the availability of amino acids...

Restriction of placental and fetal growth in sheep alters fetal blood pressure responses to angiotension II and captopril

Edwards, L.; Simonetta, G.; Owens, J.; Robinson, J.; McMillen, I.
Fonte: WILEY-BLACKWELL Publicador: WILEY-BLACKWELL
Tipo: Artigo de Revista Científica
Publicado em //1999 Português
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46.34%
1. We have measured arterial blood pressure between 115 and 145 days gestation in normally grown fetal sheep (control group; n = 16) and in fetal sheep in which growth was restricted by experimental restriction of placental growth and development (PR group; n = 13). There was no significant difference in the mean gestational arterial blood pressure between the PR (42.7 +/- 2.6 mmHg) and control groups (37.7 +/- 2.3 mmHg). Mean arterial blood pressure and arterial PO2 were significantly correlated in control animals (r = 0.53, P < 0.05, n = 16), but not in the PR group. 2. There were no changes in mean arterial blood pressure in either the PR or control groups in response to captopril (7.5 microg captopril min-1; PR group n = 7, control group n = 6) between 115 and 125 days gestation. After 135 days gestation, there was a significant decrease (P < 0.05) in the fetal arterial blood pressure in the PR group but not in the control group during the captopril infusion (15 microg captopril min-1; PR group n = 7, control group n = 6). 3. There was a significant effect (F = 14.75; P < 0.001) of increasing doses of angiotensin II on fetal diastolic blood pressure in the PR and control groups. The effects of angiotensin II were different (F = 8.67; P < 0.05) in the PR and control groups at both gestational age ranges. 4. These data indicate that arterial blood pressure may be maintained by different mechanisms in growth restricted fetuses and normally grown counterparts and suggests a role for the fetal renin-angiotensin system in the maintenance of blood pressure in growth restricted fetuses.

Insulin-like growth factor I alters renal function and stimulates renin secretion in late gestation fetal sheep

Marsh, A.; Gibson, K.; Wu, J.; Owens, P.; Owens, J.; Lumbers, E.
Fonte: Cambridge Univ Press Publicador: Cambridge Univ Press
Tipo: Artigo de Revista Científica
Publicado em //2001 Português
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46.24%
1 While it is known that treatment with insulin-like growth factor I (IGF-I) stimulates growth of the fetal kidney, nothing is known about the short term or long term effects of IGF-I on fetal renal function. To investigate the acute effects of IGF-I on fetal renal function and on the activity of the fetal renin-angiotensin system, studies were carried out in 12 chronically catheterized fetal sheep aged 120 ± 1 days, before and during a 4 h I.V. infusion of IGF-I at 80 μg h1. Seven control fetuses were infused over the same period with vehicle (0.1% bovine serum albumin in 0.15 M saline). 2 IGF-I infusion increased plasma IGF-I concentrations by about 80%. There was a small fall in arterial PO2 (P < 0.01), arterial PCO2 increased (P < 0.05), plasma lactate levels increased (P < 0.01) and arterial pH fell (P < 0.05). Fractional bicarbonate reabsorption increased and bicarbonate excretion decreased (P < 0.05). 3 Infusions of IGF-I had no sustained effect on fetal arterial pressure. Glomerular filtration rate (GFR) did not change significantly during IGF-I infusion, but renal blood flow (RBF) fell (P < 0.05). Therefore filtration fraction relative to control values increased (P < 0.05), suggesting that efferent arteriolar vasoconstriction had occurred. 4 IGF-I infusion led to an antidiuresis (P < 0.01)...

Maternal undernutrition and fetal blood pressure and the hypothalamo-pituitary adrenal axis in the late gestation fetal sheep / Lisa Jane Edwards.

Edwards, Lisa Jane
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado Formato: 109179 bytes; application/pdf
Publicado em //2001 Português
Relevância na Pesquisa
56.12%
Aims to determine the impact of maternal undernutrition during late gestation and during the periconceptional and gestational periods on fetal growth, fetal blood pressure and the fetal hypothalamo-pituitary adrenal axis in the sheep.; Thesis (Ph.D.)--University of Adelaide, Dept. of Physiology, 2001; Includes bibliographical references (leaves 228-257).; xxii, 257 leaves : ill. ; 30 cm.

Circulating insulin-like growth factors-I and -II and substrates in fetal sheep following restriction of placental growth

Owens, J.A.; Kind, K.L.; Carbone, F.; Robinson, J.S.; Owens, P.C.
Fonte: BioScientifica Publicador: BioScientifica
Tipo: Artigo de Revista Científica
Publicado em //1994 Português
Relevância na Pesquisa
46.34%
To determine the relationship between placental delivery of oxygen and glucose, circulating insulin-like growth factors (IGFs) and fetal growth, the effect of variable restriction of placental growth was determined in sheep in late gestation. Arterial blood was obtained via indwelling catheters at 120 and 127 days of gestation, prior to necropsy at 130 days to measure fetal and placental weights. Plasma was acidified and subjected to size-exclusion high-performance liquid chromatography at pH 2.8 to dissociate and separate IGFs from their binding proteins. The acid-dissociated IGF fraction was analysed by sensitive and highly specific radioligand assays for IGF-I and IGF-II, previously defined using ovine IGFs. Fetal weight and blood pO2 and glucose at 120 and 127 days of gestation correlated positively with placental weight. Plasma IGF-I was positively associated with fetal weight and fetal liver weight, and with blood pO2 and glucose at both ages. Plasma IGF-II levels also correlated positively with fetal weight, fetal liver weight and with blood glucose and pO2, but only at 127 days of gestation. In the most severely growth-retarded fetal sheep, blood glucose and pO2 and plasma IGF-I were significantly reduced when compared with normal fetuses at 120 days. All decreased further by 127 days of gestation as did plasma IGF-II in severely growth-retarded fetal sheep compared with normal fetuses. These observations are consistent with the hypothesis that both IGF-I and IGF-II are chronically regulated by oxygen and nutrition in utero and mediate part of the influence of placental supply of substrate over fetal growth.; J A Owens...

Effectiveness of electronic fetal monitoring with additional ST analysis in vertex singleton pregnancies at >36 weeks of gestation: an individual participant data metaanalysis

Schuit, E.; Amer-Wahlin, I.; Ojala, K.; Vayssiere, C.; Westerhuis, M.; Marsal, K.; Tekay, A.; Saade, G.; Visser, G.; Groenwold, R.; Moons, K.; Mol, B.; Kwee, A.
Fonte: Mosby Publicador: Mosby
Tipo: Artigo de Revista Científica
Publicado em //2013 Português
Relevância na Pesquisa
56.18%
OBJECTIVE: The purpose of this study was to assess the effectiveness of electronic fetal monitoring (EFM) alone and with additional ST analysis (EFM+ST) in laboring women with a singleton term pregnancy that is in cephalic presentation in the prevention of metabolic acidosis by the application of individual patient data metaanalysis. STUDY DESIGN: We conducted an individual patient data metaanalysis using data from 4 randomized trials, which enabled us to account for missing data and investigate relevant subgroups. The primary outcome was metabolic acidosis, which was defined as an umbilical cord-artery pH <7.05 and a base deficit that had been calculated in the extra cellular fluid compartment >12 mmol/L. We performed 8 explanatory subgroup analyses for 8 different endpoints. RESULTS: We analyzed data from 12,987 women and their newborn infants. Metabolic acidosis was present in 57 women (0.9%) in the EFM+ST group and 73 women (1.1%) in the EFM alone group (relative risk [RR], 0.76; 95% CI, 0.53–1.10). Compared with EFM alone, the use of EFM+ST resulted in a reduction in the frequency of instrumental vaginal deliveries (RR, 0.90; 95% CI, 0.83– 0.99) and fetal blood samples (RR, 0.49; 95% CI, 0.44–0.55). Cesarean delivery rates were comparable between both groups (RR...

Fetal blood sampling in addition to intrapartum ST-analysis of the fetal electrocardiogram: evaluation of the recommendations in the Dutch STAN® trial; Fetal blood sampling in addition to intrapartum ST-analysis of the fetal electrocardiogram: evaluation of the recommendations in the Dutch STAN(R) trial

Becker, J.; Westerhuis, M.; Sterrenburg, K.; Van den Akker, E.; van Beek, E.; Bolte, A.; Van Dessel, T.; Drogtrop, A.; van Geijn, H.; Graziosi, G.; van Lith, J.; Mol, B.; Moons, K.; Nijhuis, J.; Oei, S.; Oosterbaan, H.; Porath, M.; Rijnders, R.; Schuitema
Fonte: Wiley Publicador: Wiley
Tipo: Artigo de Revista Científica
Publicado em //2011 Português
Relevância na Pesquisa
66.29%
Objectives:  To evaluate the recommendations for additional fetal blood sampling (FBS) when using ST-analysis of the fetal electrocardiogram. Design:  Prospective cohort study. Setting:  Three academic and six non-academic teaching hospitals in the Netherlands. Population:  Labouring women with a high-risk singleton pregnancy in cephalic position beyond 36 weeks of gestation. Methods:  In labouring women allocated to the STAN® arm of a previously published randomised controlled trial who underwent one or more FBS during delivery, we assessed whether FBS was performed according to the trial protocol and how fetal acidosis, defined as an FBS pH < 7.20, was related to ST-waveform analysis. Main outcome measures:  The number of FBS showing fetal acidosis, related to the different STAN® criteria where additional FBS is recommended. Results:  Among 2827 women monitored with STAN®, 297 underwent FBS, of whom 171 (57.6%) were performed according to the predefined criteria and 126 were performed in absence of these criteria. In the first group, rates of fetal acidosis (pH < 7.20) were two of 18, none of nine, 12 of 111 and three of 33 when FBS was taken for abnormal cardiotocogram (CTG) at the start, intermediary CTG at the start...

Effect of restriction of placental growth on umbilical and uterine blood flows

Owens, J.A.; Falconer, J.; Robinson, J.S.
Fonte: American Physiological Society Publicador: American Physiological Society
Tipo: Artigo de Revista Científica
Publicado em //1986 Português
Relevância na Pesquisa
46.24%
Endometrial caruncles were excised from sheep (caruncle sheep) before pregnancy. The effect of this on umbilical and uterine blood flows in a subsequent pregnancy was examined. Thirteen caruncle and twelve control sheep with indwelling vascular catheters were studied at 121 and 130 days pregnancy. In caruncle sheep, fetal, placental, and total uterine content weights were significantly lower than in control sheep. Six caruncle sheep carried normal-sized fetuses (weight within +/- 2 SD of mean weight for control fetuses) and seven carried small fetuses (weight greater than +/- 2 SD below mean weight for control fetuses). Mean weights of placentas in these groups were 0.290 +/- 0.067 and 0.156 +/- 0.069 kg, respectively, compared with 0.459 +/- 0.157 kg in control sheep. In small caruncle fetuses, umbilical and uterine blood flows and placental antipyrine clearance were significantly lower than in controls at 121 and 130 days gestation. Only umbilical blood flow was reduced in normal-sized caruncle fetuses. Umbilical blood flow and placental antipyrine clearance increased with gestational age in control sheep but not in sheep with normal-sized or small caruncle fetuses. In all sheep, umbilical and uterine blood flows and antipyrine clearance correlated with placental weight. Umbilical blood flow per kilogram of placenta but not uterine blood flow per kilogram of placenta correlated inversely with placental weight. Fetal weight at 130 days generally correlated with placental weight...

Techniques of intrauterine fetal transfusion for women with red-cell isoimmunisation for improving health outcomes.

Dodd, J.; Windrim, R.; vanKamp, I.
Fonte: Update Software Ltd Publicador: Update Software Ltd
Tipo: Artigo de Revista Científica
Publicado em //2012 Português
Relevância na Pesquisa
46.3%
BACKGROUND Red-cell alloimmunisation can occur when there are incompatibilities between a woman's blood type and that of her unborn baby. This can cause the baby to become anaemic (low red blood cell count), which may require treatment during the pregnancy by blood transfusion while the baby remains within the uterus (called an intrauterine blood transfusion). OBJECTIVES To compare, using the best available evidence, the benefits and harms of different techniques of intrauterine fetal blood transfusion for women with red-cell alloimmunisation. SEARCH METHODS We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (13 June 2012). SELECTION CRITERIA We considered randomised controlled trials comparing different techniques of intrauterine fetal blood transfusion (either alone or in combination with another technique) for inclusion. DATA COLLECTION AND ANALYSIS Two authors evaluated trials under consideration for appropriateness for inclusion and methodological quality, without consideration of their results according to the prestated eligibility criteria. We planned to use a fixed-effect meta-analysis for combining study data if we judged the trials to be sufficiently similar. We planned to investigate statistical heterogeneity using the I² statistic; if this indicated a high degree of statistical heterogeneity...

Polybrominated diphenyl ethers in maternal and fetal blood samples.

Mazdai, Anita; Dodder, Nathan G; Abernathy, Mary Pell; Hites, Ronald A; Bigsby, Robert M
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/2003 Português
Relevância na Pesquisa
46.28%
Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants in consumer goods, such as plastics, electronics, textiles, and construction material. PBDEs have been found in human milk, fat, and blood samples. Rodent studies indicate that PBDEs may be detrimental to neurodevelopment, possibly by lowering thyroid hormone concentrations in blood. In the present study, we determined concentrations of PBDEs and thyroid hormones in human fetal and maternal serum. Patients presenting in labor to Indiana University and Wishard Memorial County hospitals in Indianapolis, who were older than 18 years, were recruited to participate. Twelve paired samples of maternal and cord blood were obtained and analyzed using gas chromatographic mass spectrometry; thyroid hormone concentrations were determined by radioimmunoassay. Six congeners of PBDE were measured in maternal and fetal serum samples. The concentrations of total PBDEs found in maternal sera ranged from 15 to 580 ng/g lipid, and the concentrations found in fetal samples ranged from 14 to 460 ng/g lipid. Individual fetal blood concentrations did not differ from the corresponding maternal concentrations, indicating that measurement of maternal PBDE blood levels is useful in predicting fetal exposure; similarly...

Sampling pure fetal blood by fetoscopy in second trimester of pregnancy.

Rodeck, C H; Campbell, S
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 09/09/1978 Português
Relevância na Pesquisa
46.29%
A technique for fetal blood-sampling in the second trimester of pregnancy (between 16 and 22 weeks' gestation) combining fetoscopy with real-time ultrasound was used in 48 attempts at fetal blood-sampling. Specimens containing fetal red cells with or without amniotic fluid or maternal blood, and adequate for diagnosing haemoglobinopathies, were obtained in 45 of the 48 fetoscopies. Sampling was successful in all 18 patients with a posterior placenta, and in 27 of the 30 with an anterior placenta. In 22 of the last 27 consecutive fetoscopies pure fetal blood was taken; the placenta was anterior in 16 and posterior in six. Out of 17 cases sampled between 18 and 22 weeks' gestation pure fetal blood was obtained in 16. The volume of the samples varied from 50 to 500 microliter. The ability to obtain pure fetal blood consistently even when the placenta is anterior will increase knowledge of fetal physiology and the scope of prenatal diagnosis.

Fetal in vivo continuous cardiovascular function during chronic hypoxia; Fetal brain sparing during chronic hypoxia

Allison, B. J.; Brain, K. L.; Niu, Y.; Kane, A. D.; Herrera, E. A.; Thakor, A. S.; Botting, K. J.; Cross, C. M.; Itani, N.; Skeffington, K. L.; Beck, C.; Giussani, D. A.
Fonte: Wiley Publicador: Wiley
Tipo: Article; accepted version
Português
Relevância na Pesquisa
46.3%
This is the accepted manuscript. It is currently embargoed pending publication.; Although the fetal cardiovascular defence to acute hypoxia and the physiology underlying it have been established for decades, how the fetal cardiovascular system responds to chronic hypoxia has been comparatively understudied. We designed and created isobaric hypoxic chambers able to maintain pregnant sheep for prolonged periods of gestation under controlled significant (10% O2) hypoxia, yielding fetal mean PaO2 levels (11.5?0.6 mmHg) similar to those measured in human fetuses of hypoxic pregnancy. We also created a wireless data acquisition system able to record fetal blood flow signals in addition to fetal blood pressure and heart rate from free moving ewes as the hypoxic pregnancy is developing. We determined in vivo longitudinal changes in fetal cardiovascular function including parallel measurement of fetal carotid and femoral blood flow and oxygen and glucose delivery during the last third of gestation. The ratio of oxygen (from 2.7?0.2 to 3.8?0.8; P<0.05) and of glucose (from 2.3?0.1 to 3.3?0.6; P<0.05) delivery to the fetal carotid, relative to the fetal femoral circulation increased during and shortly after the period of chronic hypoxia. In contrast...

Signiture analysis of fetal blood velocity waveforms

Soule, Ronald
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
56.21%
Doppler blood velocity waveform analysis is conducted to affect clinical diagnosis. Current analysis codes developed at RIT posses the capability to assess gross hemodynamic parameters such as heart rate, mean pulse velocity, peak systolic velocity and also the beat to beat variability of these parameters. These computer algorithms have, however, lacked the ability to determine hemodynamic indices such as the pulsatility and resistance index as well as the AB ratio. This latter deficiency stems from an algorithmic need to accurately determine end diastolic velocity in every cardiac cycle. The current thesis specifically augments current algorithms to accurately compute end diastolic velocity. The end diastolic velocity, peak systolic velocity and mean pulse velocity determined in each cardiac cycle are then used to compute the various pulsevelocity waveform indices noted above. In addition, the use of end diastolic velocity in conjunction with peak systolic velocity allows the velocity waveform to be dissected into diastolic subsections, which resemble decaying exponential curves. These exponential decay curves will be characterized via curve fitting. The goal of this thesis is to assess whether traditional pulsatility indices and/or the decay curve parameters are adequate to assess fetal developmental age between 10-13 weeks gestation. Discrimination assessment is conducted using neural network analysis techniques. Whether entire pulsevelocity waveforms extracted between successive end-diastolic velocities provides a more robust data set for gestational age discrimination is also explored. The results suggest that hemodynamic indices computed for fetuses between 10 to 13 weeks gestation provide insufficient data for effective neural network classification. Use of the entire pulse-velocity waveform data in neural network analysis showed better fetal gestational age classification than use of waveform indices. However...