As células-tronco podem ser isoladas tanto de tecidos embrionários quanto de tecidos provenientes de um organismo adulto. Este projeto teve por objetivo caracterizar, descrever as células derivadas da região uterina e da cinta placentária junção materno/fetal da placenta de carnívoros domésticos (cães e gatos), e verificar a sua capacidade de pluripotência. Os úteros gestantes e não gestantes foram obtidos em campanhas de castrações e de controle populacional de cães e gatos, na cidade de Pirassununga/SP. Foram coletados 24 úteros gravídicos de animais hígidos, em diferentes idades gestacionais. O material foi dividido em três fases distintas da gestação, ou seja inicio que compreende de 8 a 20 dias de gestação; meio de 21 a 30 dias de gestação e final de 31 a 60 dias de gestação. O material foi coletado de fêmeas caninas e felinas, quatro úteros de cada fase, totalizando 12 úteros de cães e 12 de felinos. Coletamos também 8 úteros de fêmeas nulíparas (4 de cadelas e 4 de gatas) e 8 úteros com um mês pós parto (4 de cadelas e 4 de gatas). As amostras foram fixadas em paraformoldeido tamponado a 4% para a análise histológica e de imunohistoquimica. Para a padronização da imunohistoquimica inúmeros testes de marcação e diluição dos anticorpos utilizados nesta pesquisa foram realizados, todo protocolo aqui descrito foi padronizado pela primeira vez. Nas análises de imunohistoquimica avaliamos a expressão de marcadores associados a células-tronco pluripotentes Nanog, Oct4 e Sox2. Nas cadelas, as marcações foram positivas em todas as fases, gestacionais e não gestacionais. A detecção dessas proteínas nesta espécie ficaram padronizadas, destacando algumas diferenças quantitativas durante alguns períodos da gestação. Foi observado que o Oct4 na cadela, mostra uma diferença significativa (p=0,0064), entre as fases de início e meio da gestação e entra o início e a fase de termo. Quando comparados os resultados das análises imunohistoquimicas utilizando os três anticorpos entre si, nos três períodos gestacionais ficou evidente uma diferença (p=0,0005) somente relativa a proteína Nanog com Oct4. Nas gatas apenas foi possível padronizar o protocolo do Nanog e do Sox2, sendo a marcação feita com Oct4 negativa. Nesta espécie foi possível observar uma diferença da proteína Nanog (p=0,0006) quando comparada na fase inicial para a fase do meio e início da gestação para a fase termo. No que se refere as fêmeas nulíparas e fêmeas pós-parto destaca-se a ausência de diferenças quando comparados os anticorpos na fase pós parto tanto em cadelas quanto em gatas. Na fase nulípara foram observadas diferenças somente na cadela (p=0,0018) para os três anticorpos. Desta forma, a caracterização de células de origem placentária com característica de células tronco pode abrir um leque de possibilidades para obtenção destas células de forma mais ética, uma vez que este material é descartado na castrações. Foi possível a identificação das células que expressão proteínas pluripotentes em diferentes idades gestacionais, tanto na região de cinta placentária como no útero. Apesar de semelhantes, as espécies aqui estudadas apresentaram diferenças na realização do protocolo da imunihistoquímica. Pesquisas relacionadas com as células-tronco do endométrio vêm crescendo, principalmente porque estas células podem ser facilmente obtidas, a partir de fontes descartadas, sem entraves éticos. Desta forma tem o potencial de serem uma nova fonte para o desenvolvimento na terapêutica como terapia celular / The stem cells can be isolated both embryonic tissues as much tissues from an adult organism. This project had from objective characterize and describe cells derived from uterine region and placental girdle - maternal junction / fetal placenta of domestics carnivores (dogs and cats), and check their capacity of pluripotency. The uterus pregnant and non-pregnants were obtained in castrations campaigns and population control of dogs and cats in the city of Pirassununga/SP. Were collected 24 uterus gravidic of healthy animals at different gestational ages. The material was split into three separate stages of pregnancy,that is, the Startconsist of 8 to 20 days of gestation;between21-30 days of gestation and end 31-60 days of gestation. The material was colleted from canine and feline females, four uterus each phase 12 uterus of dogs and 12 uterus of cats. We also collect 8 nulliparous female uterus (4 of dogs and 4 of cats) and 8 uterus with a postpartum month (4 of dogs and 4 of cats). The samples were fixed in paraformoldeido at 4% for histological analysis and immunohistochemical. For the standardization of immunohistochemical, were made numerous tests of marking and dilution of antibodies all the protocol described here has been standardized for the first time. In immunohistochemical analysis, we evaluated the expression of markers associated with pluripotent stem cells Nanog, Oct4 and Sox2. In cats, it was only possible to standardize the protocol of the Nanog and of the Sox2, and marking made with negative Oct4. This species was possible was possible to observe a difference in the Nanog protein (p = 0.0006) compared with the initial phase to the medium and early pregnancy to the term phase. As regards the nulliparous females and postpartum females there is the absence of differences when compared to the antibodies in postpartum stage, both in dogs and in cats. In nulliparous phase differences were only observed in dogs (p = 0.0018) for the three antibodies. Thus, the characterization of placental origin cells with stem cell characteristic can open up a range of possibilities for obtaining such cells more ethical, since this material is discarded in castration. The identification of pluripotent cells expressing proteins at different gestational ages was possible in both placental belt region as in utero. Although similar, the species studied here showed differences in the realization of immunohistochemical protocol. Searches related to the endometrial stem cells are growing, mainly because these cells can be easily obtained from sources discarded without ethical barriers. This way has the potential to be a new source for development in the therapeutic cell therapy

Made available in DSpace on 2014-08-20T14:37:54Z (GMT). No. of bitstreams: 1 dissertacao_carlos_anselmo_dos_santos.pdf: 1427076 bytes, checksum: 1086b1dabfc021879cc96d4ab3af80a8 (MD5) Previous issue date: 2013-01-17 / The cardiovascular changes in horses with laminitis are described since the 70's, however few studies have been conducted to demonstrate such changes in pregnant mares with chronic laminitis. The present study aims to evaluate blood pressure, heart rate, serum cortisol levels, gestational age and placental changes of pregnant mares with chronic laminitis and its consequences for fetal morphometry. A prospective longitudinal case-control was conducted in 6 Thoroughbred horse farms in southern Rio Grande do Sul - Brazil. Were used a total of 20 multiparous mares (10 control animals and 10 animals with chronic laminitis). The selected animals were subjected to clinical examination, blood sample collection and blood pressure measurement on alternate days in the last month of pregnancy. Serum levels of cortisol were obtained by chemiluminescence, and blood pressure measurement by indirect method and apparatus for noninvasive oscillometric sphygmomanometer at the base of the tail. Assessment of placental was effected by using the histological method of Schlafer (2004) and morphometric using ImageJ® software. Mean control group regarding measurements of systolic blood pressure were 98,3 ± 1,41 mmHg. The average diastolic blood pressure was 62,2 ± 1,14 mmHg. The mean heart rate was 44 ± 0,53 bpm and the mean serum cortisol levels were 5,06 ± 0,14 &#956;g/dL. The group of pregnant mares with chronic laminitis kept the mean systolic blood pressure and heart rate higher than the control group, being respectively 116 ± 6,73 mmHg and 52 ± 4 bpm. The average values of diastolic blood pressure was 70 ± 7,3 mmHg and mean serum cortisol was 5,07 ± 0,19 &#956;g/dL with no difference compared to the control group. The placentas of pregnant mares with laminitis had higher number of chronic histological changes and higher wall thickness / lumen than the control group (p <0,05). The foals born from mares of the control group had higher birth weight than foals born from chronic laminitis s group mares (p <0,05). / As alterações cardiovasculares em cavalos com laminite são descritas desde a década de 70, porem poucos estudos foram realizados para demonstrar tais alterações em éguas gestantes com laminite crônica. O presente estudo tem como objetivo avaliar a pressão arterial, frequência cardíaca, níveis de cortisol séricos, tempo gestacional e alterações placentárias de éguas gestantes com laminite crônica e suas consequências sobre a morfometria fetal. Foi realizado um estudo prospectivo longitudinal de caso controle em 6 criatórios de equinos Puro Sangue Inglês na região sul do Rio Grande do Sul Brasil. Foram utilizados um total de 20 éguas multíparas (10 animais do grupo controle e 10 animais com laminite crônica). Os animais selecionados foram submetidos ao exame clínico, coletas de sangue e mensurações da pressão arterial em dias alternados no último mês de gestação. Os níveis séricos de cortisol foram obtidos pelo método de quimiluminescência, e a aferição da pressão arterial através do método indireto e não invasivo por aparelho de esfigmomanômetro oscilométrico na base da cauda. A avaliação placentária foi efetuada por meio histológico utilizando o método de Schlafer (2004) e morfométrico utilizando o programa de domínio público ImageJ. Os valores médios do grupo controle referentes às aferições da pressão arterial sistólica foram de 98,3 ±1,41mmHg. O valor médio da pressão arterial diastólica foi de 62,2 ±1,14mmHg. A frequência cardíaca média foi de 44 ±0,53 bpm e as médias dos níveis séricos de cortisol foram de 5,06 ±0,14 &#956;g/dL. O grupo de éguas gestantes com laminite crônica manteve as médias de pressão arterial sistólica e frequência cardíaca mais altas que ao grupo controle, sendo respectivamente, 116 ±6,73 mmHg e 52 ±4 bpm. Os valores médios obtidos da pressão arterial diastólica foi de 70 ±7,3 mmHg e a media dos níveis séricos de cortisol foi de 5,07± 0,19 &#956;g/dL não havendo diferença em relação ao grupo controle. As placentas do grupo de éguas gestantes com laminite crônica obtiveram maior número de alterações histológicas e maior relação de espessura parede/luz arterial que o grupo controle (p<0,05). Os potros provenientes das gestações de éguas do grupo controle obtiveram peso ao nascimento superior aos potros nascidos do grupo de éguas com laminite crônica (p<0,05).

Abstract Abnormal placentation is associated with preeclampsia and placental insufficiency, both of which increase the risk for fetal growth restriction. So far the early recognition of the risk population for preeclampsia has been problematic. The first hypothesis of this study was that in preeclampsia, the maternal serum proteomic profile is different from that in uncomplicated pregnancies, and this difference is detectable already in early pregnancy. The findings of this study demonstrate that in clinical preeclampsia the maternal serum proteomic profile is different from that in uncomplicated pregnancies with increased levels of placental proteins and antiangiogenic factors in pregnancies with clinical preeclampsia. Furthermore, the early pregnancy maternal serum proteomic profile in women who later develop preeclampsia revealed a distinct and different pattern compared with the profile in clinical preeclampsia. In early pregnancy, the differentially expressed proteins belong to placental proteins, vascular and/or transport proteins and matrix and/or acute phase proteins, while angiogenic and antiangiogenic proteins were not significantly expressed in early pregnancy. Preeclampsia, placental insufficiency, fetal growth restriction and type-1 diabetes may have an impact on fetal cardiovascular hemodynamics. The second hypothesis in this thesis was that in placental insufficiency, abnormalities in fetal cardiovascular status correlate with biochemical markers of cardiac dysfunction and chronic hypoxia. In placental insufficiency, increases in fetal N-terminal pro-atrial (NT-proANP) and pro-B-type natriuretic peptide (NT-proBNP) and in fetal erythropoietin concentrations were related to increased pulsatility in the fetal umbilical artery and descending aorta. In addition, these fetuses demonstrated increased pulsatility in their systemic venous blood velocity waveforms. Thus, in placental insufficiency, biochemical markers of cardiac dysfunction and chronic hypoxia are associated with signs of increased fetal cardiac afterload and systemic venous pressure. Increased NT-proANP and NT-proBNP levels were also detected in fetuses of type-1 diabetic mothers with normal umbilical artery velocimetry. In these pregnancies, NT-proANP and NT-proBNP levels were related to poor maternal glycemic control during early pregnancy.

Des modifications physiologiques importantes interviennent au cours de la grossesse. Ces modifications ont un impact sur la pharmacocinétique et/ou la pharmacodynamique des traitements administrés. Chez la femme infectée par le virus du VIH, un traitement antirétroviral adéquat et efficace est indispensable pour la santé de la mère et pour assurer la prévention de la transmission du virus au nouveau-né. Pour un traitement optimal, en termes d’efficacité et de non-toxicité, la connaissance de l’effet de la grossesse sur les concentrations des antirétroviraux chez la mère ainsi que leur passage transplacentaire est primordiale. Dans cette thèse nous avons utilisé une méthodologie adaptée pour cette population : la modélisation non linéaire à effets mixtes. Des données de suivi thérapeutique pharmacologique, ainsi que les données d’un essai clinique multicentrique (TEmAA) ont été analysées grâce à deux logiciel : NONMEM et Monolix.Dans la première étude présentée, nous nous sommes intéressés à la pharmacocinétique dutenofovir chez la femme enceinte. Nous avons mis en évidence un effet relativement important de la grossesse, en effet une augmentation de 39% de la clairance est observée chezla femme enceinte et la femme parturiente. Une augmentation de la dose serait donc souhaitable chez ces femmes. Dans la deuxième étude, nous avons mis en évidence une légère augmentation de l’exposition à la lamivudine au cours de la grossesse, ne nécessitant pas d’adaptation de posologie. Dans la troisième étude, les concentrations de névirpaine chez la mère et son nouveau-né ont été analysées et le schéma d’administration a été évalué.Dans la dernière étude, à partir des concentrations de tenofovir et d’emtricitabine dans le lait maternel qui sont ici reportées pour la première fois chez l’homme, nous avons simulé les profils de concentrations obtenus chez le nourrisson. / Important physiological changes occur during pregnancy. These changes may affect the pharmacokinetics and/or pharmacodynamics of the administered medication. In HIV infected women, antiretroviral treatment adequacy and effectiveness is essential for the health of the mother and for the prevention of HIV transmission to the newborn. For optimal treatment interms of efficacy and tolerance, the effect of pregnancy on antiretroviral concentrations in themother and their transplacental passage have to be assessed.In this work we used the appropriate methodology in this population: non linear mixed effects modeling. Data from therapeutic drug monitoring, as well as data from a multicenter clinical trial (TEmAA) were analyzed using: NONMEM or Monolix. In the first study presented, we investigated the pharmacokinetics of tenofovir in pregnant women. We observed a relatively large effect of pregnancy, a 39% increase of the apparent clearance in pregnant and parturient woman. A dose increase should be therefore investigated in these women. In the second study, we demonstrated a slight increase in lamivudine exposure during pregnancy. This increase does not require dose adjustment. In the third study, the concentration of nevirapinein the mother and her newborn were analyzed and the administration scheme was evaluated.In the last study, based on concentrations of tenofovir and emtricitabine in breast milk that arereported here for the first time in humans, we simulated the concentration profiles obtained ininfants.

Radioimmunotherapy (RIT) and radioimmunolocalisation (RIL) are developing and promising technologies to diagnose and treat tumours by use of radiolabelled antibodies targeting tumour specific antigens. The major reason why RIL and RIT not are efficient enough, is the comparatively low accumulation of radiolabelled antibodies in the tumours. Irrespective of the antigen - antibody system used, the maximal tumour uptake in humans is often limited to below 0.1 % of the total injected dose, with significant radionuclide remaining in the blood pool and extravascular fluid. In the present thesis, the following putative improvement techniques for radioimmunotargeting have been evaluated in an experimental model using HeLa cell-xenografted nude mice: 1) Repetitive, simultaneous targeting of different antigens, 2) Removal of non-targeting antibodies using secondary antiidiotypic antibodies, 3) Preinjection of unlabelled antibody to remove shedded antigen and 4) Use of fractionated antibody administration. By use of multiple injections of mixtures of two different 131I-labelled monoclonal antibodies targeting placental alkaline phosphatase (H7) and cytokeratin 8 (TS1), respectively, a significant tumour growth inhibition compared to controls, was obtained. In the treated group, a negligible increase in tumour volume was seen compared to the control group, in which a 20-fold increase was observed. Quantitative determinations of volume densities of viable tumour cells, necrotic cells and connective tissue demonstrated no significant differences in the relative proportions between the groups, indicating that the irradiation caused decelerated growth. Using hybridoma technology, monoclonal antiidiotypic antibodies were generated against both TS1 and H7. The in vitro and in vivo effects of these antibodies, aH7 and aTSl, were investigated. Both these antiidiotypes were found to generate stable complexes with the radiolabelled idiotypic antibody, as revealed by gel-electrophoresis and autoradiography. Using biosensor technology (BIAcore, Pharmacia) the interactions were followed in real time and the association rate-, dissociation rate-, and affinity constants between the reactants were determined. In vivo, the antiidiotypes promoted a rapid dose dependent clearance of the 125I-labelled idiotypes with a decrease in total body radioactivity and concomitant dramatic increase in non-protein bound 125I excreted in the urine. The syngeneic monoclonal antiidiotypic antibody αTSl, was furthermore evaluated as a secondary clearing antibody at radioimmunolocalisation. Injection of αTSl in a molar ratio of 0.5-0.75:1 to TS1, 24 hours after the 125I-labelled TS1 improved the tumour to normal tissue ratio 2-3 fold. This was due to a decreased level of total body radioactivity as well as a slight decrease in tumour-radioactivity. A model describing the kinetics of the involved components, i.e. the antigen, the idiotype and the antiidiotype was presented. It is concluded that high affinity monoclonal antiidiotypes can be used as tools to regulate the levels of idiotypic antibodies in vivo. This strategy, combined with preinjection of non­labelled idiotypic antibodies, caused accumulated doses of 3 Gy to the tumour and 0.9 Gy to non tumour tissues as calculated for 125I-labelled antibodies (80 MBq/mg) by MIRD formalism based on repetitive quantitative radioimmunoscintigraphies. By approaching the maximal tolerated whole body radiation dose for mice (i.e. 6 Gy), it can be estimated that doses up to 20 Gy are possible to obtain following one single injection of labelled antibody. It was furthermore demonstrated that a single bolus injection of antibody is to be preferred, compared to exactly the same dose divided into three or ten fractions. Thus, not only the dose of radioactivity, but also the amount of antibody should be considered for fractionated RIT. In summary, the thesis demonstrates that several techniques can be used to improve radioimmunolocalisation and to approach the proposed 70 Gy required to sterilise tumours at radioimmunotherapy. / digitalisering@umu.se

Abstract Knowledge of the effects of maternally administered vasopressors on human fetal and placental haemodynamics is sparse and limited to elective Caesarean deliveries in uncomplicated pregnancies. We hypothesized that, after short-term fetal hypoxaemia, which activates fetal cardiovascular compensatory mechanisms, treatment of maternal hypotension with ephedrine or phenylephrine results in divergent responses in fetal and placental haemodynamics. Chronically instrumented near-term sheep fetuses with either normal placental function or increased placental vascular resistance following placental embolization were exposed to two subsequent periods of decreased fetal oxygenation caused by maternal hypoxaemia and epidural-induced hypotension. The fetuses that underwent placental embolization were also chronically hypoxaemic. Fetal and placental haemodynamics were assessed by invasive techniques and by noninvasive Doppler ultrasonography. Our results show that umbilical artery blood flow velocity waveforms cannot be used to derive information of fetal cardiac function. Furthermore, the changes in placental volume blood flows and vascular resistances caused by maternal vasopressor treatment cannot be reliably recognized based on uterine and umbilical artery pulsatility index values. In response to acute hypoxaemia, a fetus with normal placental function redistributes its right ventricular cardiac output from the pulmonary to the systemic circulation and is able to increase its combined cardiac output, with a concomitant relative decrease in the net forward flow through the aortic isthmus. However, fetal haemodynamic responses to subsequent hypoxaemic insults may vary. Furthermore, the compensatory responses of fetuses with increased placental vascular resistance differ from those of normal fetuses. In these fetuses, repeated episodes of a further decrease in oxygenation lead to lactataemia. The effects of ephedrine on uteroplacental and umbilicoplacental circulations were more favourable than those of phenylephrine. Ephedrine restored the changes in fetal cardiovascular haemodynamics caused by maternal hypotension to the baseline conditions in both embolized and nonembolized fetuses. Phenylephrine did not reverse fetal pulmonary vasoconstriction or the relative decrease in the net forward flow through the aortic isthmus. Moreover, fetal left ventricular function was impaired by phenylephrine. Although no significant differences in fetal acid-base status were observed in fetuses with normal placental function, the lactate concentrations of the embolized fetuses increased further when maternal hypotension was treated with phenylephrine.

Le tabagisme actif par la mère expose le fœtus en développement à des agents qui peuvent traverser la barrière placentaire et interférer avec les fonctions placentaires. Un large éventail de fonctions immunologiques, pourrait être compromises. Dans cette étude, nous avons évalué l'effet de l'extrait de la fumée de cigarette (CSE) sur les macrophages isolés à partir de placentas humains (pMφs), qui sont les principaux partenaires de l'immunité de fœto-maternelle innée. J’ai pu montrer que le CSE inhibe la formation des cellules géantes multinucléées (MGC). Cette propriété du CSE est spécifique aux macrophages car la fusion des macrophages dérivés des monocytes est inhibée lors de la formation de granulomes in vitro. J’ai également étudié l'absorption de particules et la production de cytokines par pMφs exposés au CSE. Le CSE a inhibé l'absorption des particules de zymosan, mais pas celle du zymosan opsonisé, ce qui suggère qu’il interfère avec les récepteurs phagocytaires et non phagocytaires. Le CSE augmente la libération de TNF et d'IL-33, et une diminue celle de l'IL-10, ce qui montre que l'équilibre entre les cytokines est affecté par le CSE. En outre, l’expression des métalloprotéinases telles que les MMP-1, MMP-10 et MMP-12, connues pour être impliquées dans le remodelage des tissus et la fusion des macrophages est dérégulée. Enfin, j’ai montré que la nicotine, l'un des principaux composés de tabac, n'a pas affecté les propriétés fonctionnelles des pMφs. / Active smoking by the mother exposes the developing fetus to agents that can cross the placental barrier and interfere with placental functions. A wide range of immunological functions, including innate and adaptive immune responses, might be impaired. In this study, we assessed the effect of cigarette smoke extract (CSE) on macrophages isolated from human placentas (pMφs), which are major partners of innate feto-maternal immunity. I showed that CSE significantly inhibited the formation of multinucleated giant cells (MGCs). This property of CSE is specific to macrophages because the fusion of monocyte-derived macrophages is inhibited during the in vitro formation of granulomas. I also investigated particle uptake and cytokine production by pMφs exposed to CSE. CSE inhibited the uptake of zymosan, but not that of opsonized zymosan, suggesting that it interferes with phagocytic receptors, not with the phagocytic machinery of pMφs. CSE increased the release of Tumor Necrosis Factor and interleukin-33, and decreased that of interleukin-10, demonstrating that the balance between inflammatory and anti-inflammatory cytokines is affected by CSE. Furthermore, CSE enhanced the expression of metalloproteinase (MMPs) genes such as MMP-1, MMP-10 and MMP-12, known to be involved in tissue remodeling including macrophage fusion. Finally, I showed that nicotine, one of the major compounds of tobacco, did not affect the functional properties of pMφs.

OBJECTIVE: Our purpose was to determine the effects of insulin and glucose on glucose transport and expression of GLUT1 glucose transporter messenger ribonucleic acid in first-trimester human trophoblast-like cells. STUDY DESIGN: First-trimester human trophoblast-like cells were maintained as a continuous cell line. For 2[3H]deoxy-d-glucose uptake and messenger ribonucleic acid studies the cells were incubated in the presence or absence of insulin (10-7 to 10-11 mol/L) or d-glucose (0 to 50 mmol/L) for 0 to 24 hours. Glucose transport was measured by incubating cells with 0.1 mmol/L,2[3H]deoxy-d-glucose for 5 minutes. Specific uptake was determined by incubating companion cultures with 10 μmol/L cytochalasin B. The cells were then solubilized with sodium hydroxide and the radioactivity counted. Data were expressed as nanomoles of 2[3H]deoxy-d-glucose transported per milligram of protein per 5 minutes and analyzed by one-way analysis of variance with post hoc testing by the method of Tukey. GLUT1 messenger ribonucleic acid was measured by Northern blotting of total ribonucleic acid samples hybridized to a phosphorus 32-labeled complementary deoxyribonucleic encoding the rat GLUT1 glucose transporter. As a control for loading efficiency, blots were stripped and rehybridized to a 40-mer phosphorus 32-labeled β-actin oligonucleotide probe. RESULTS: Insulin treatment resulted in a dose-dependent increase in the transport of 2[3H]deoxy-d-glucose at 24 hours (p < 0.001 at 10-7 mol/L). This change was first detected at 12 hours of incubation. These data closely paralled the insulin-induced increase in GLUT1 messenger ribonucleic acid seen in Northern blots. In contrast to insulin, increasing concentrations of d-glucose did not change the transport of 2[3H]deoxy-d-glucose. However, when cells were incubated in low concentrations of d-glucose (0 or 1 mmol/L), an enhancement in the uptake of 2[3H]deoxy-d-glucose (p < 0.001) was observed. Kinetic studies indicated that d-glucose augmentation of 2[3H]deoxy-d-glucose uptake was significant at 9 hours (p < 0.05). The effects of d-glucose on GLUT1 messenger ribonucleic acid expression paralleled the uptake of 2[3H]deoxy-d-glucose, although the modulation of GLUT1 messenger ribonucleic acid levels by glucose was much less pronounced than in insulin-treated cells. CONCLUSION: Although it has been assumed that the placenta has a limited role in influencing glucose transport to the fetus, our in vitro data demonstrate that both insulin and glucose can modulate glucose transport at the cellular level of the placental trophoblast. Thus maternal insulin and glycemic status may influence the expression of GLUT1, the major trophoblast glucose transporter protein, therefore directly affecting first-trimester placental glucose transport. These in vitro data may help explain the association between maternal glucose abnormalities and impaired fetal development during the first trimester when placental GLUT1 messenger ribonucleic acid expression is at its peak.

Umbilical flow velocity waveforms (FVW' s) can be measured non-invasively using Doppler ultrasound. Changes in the FVW's occur long before the warning signs from other conventional monitoring methods. Correct interpretation of the changes in the FVW has the potential of providing the clinician with an early warning of foetal distress. A number of indices have been described in the literature to characterise the FVW including the Pulsatility Index (PI), the Resistance Index (RI) and more recently, the High Resistance State Index (HRSI). Researchers have shown a dependence of the FVW, and thus the indices which describe it, on factors such as the placental resistance (Muijsers et al 1990a) blood pressure pulsatility (Mulders et al 1986), and the foetal heart rate (Downing et al 1991). In order to model the foetal circulation, the dimensions of the foetal vessels were required. These were taken from the literature when available, but had to be supplemented by measurements on post mortem specimens. This information, together with blood pressures and flow rates taken from the literature, was used to design electrical analogous models of the foetal arterial circulation (model 1 and model 2), which were implemented using PSpice, which is an electronic circuit simulator package. The Flow Velocity Waveforms (FVW's) simulated were stored and then analyzed using MATLAB, which is a mathematical package to calculate the waveform indices and both the blood pressure and percentage blood flow to the different anatomical regions of the foetus. Model 1 is a simple model of the umbilical placental unit only, which assumes a rectified sine wave with a D.C. offset as an input waveform while Model 2 is a distributed element model of the complete foetal arterial system, including a realistic representation of the foetal heart. AIM: Simulations of the FVW were used to examine the effects of placental obliteration (raised placental resistance), placental size, foetal heart rate (FHR), blood pressure pulsatility (BPPI), mean blood pressure (BP), and site of measurement of the FVW along the umbilical artery and thus on the waveform indices which are used to describe it (RI, PI and HRSI). RESULTS/ DISCUSSION: The investigations using models 1 and 2 showed that the indices were significantly dependent on the placental resistance, the size of the placenta and the type of placental obliteration. Model 1 was also used to investigate the effect of FHR variations on the indices under the original assumption that the input waveform to the umbilical/placental unit was a rectified sinusoid offset by a constant voltage (D.C.) (Thompson and Trudinger 1990). The result obtained, that is, the FHR does not affect the indices (in particular the PI) needed further investigation because the assumption for the input waveform is not true under all conditions. For this reason, the simulations were repeated using model 2, with the interesting result that there is a difference between short term FHR variations and long-term FHR variation. Short term FHR variations had a pronounced effect on the indices. The blood pressure pulsatility and the indices concerned varied by large amounts in this case, which indicated a link between the blood pressure pulsatility and all the indices. Long term FHR variations had an inconsistent but small effect on the blood pressure pulsatility and in turn had a small effect on the RI and PI. The mean blood pressure in these simulations decreased with increasing FHR which resulted in a pronounced increase in the HRSI which indicated the dependency of this index on the mean blood pressure rather than on the blood pressure pulsatility. It was found that the HRSI is a good index of placental resistance and may be particularly useful in evaluating high placental resistance in cases of absent flow during diastole, since, in these cases it is only slightly affected by the FHR. A value of greater than 34 percent is the recommended HRSI value to indicate severe foetal distress. The results also indicate that the FVW shape varies along the umbilical artery and is far more pulsatile at the aortic (proximal) end than the placental end. This is reflected in the indices which thus have worst case values at the placental end. It is thus recommended that, where possible, the indices are measured at the placental end of the umbilical artery.

No description available.