The aim of this thesis was to investigate the effect of antihypertensive therapy on vascular function and placental markers in hypertensive disorders in pregnancy (HTD). We prospectively studied 208 women at the Homerton and University College London Hospitals. Vascular and serum markers were measured in 80 with HTD [51 pre-eclampsia (PE), 29 gestational hypertension (GH)] and 80 normotensive controls. The same markers were measured in placental samples from another 48 women (14 PE, 10 GH, 24 controls). Pulse wave analysis indices [augmentation pressure (AP) and augmentation index at heart rate 75/minute (Aix-75)], serum and placental concentrations of soluble fms-like tyrosine-kinase-1 (sFlt-1), soluble endoglin (sEng), placental growth factor (PIGF), vascular endothelial growth factor (VEGF), inhibin A, activin A, and uterine artery Doppler were measured before, and 24-48 hours after, initiating antihypertensive therapy. The three study groups were compared using ANOVA multiple comparisons with Bonferroni post hoc testing. Marker levels before and after antihypertensives were compared using paired t-test. In both pre-eclampsia (P < 0.0001) and gestational hypertension (P < 0.05), serum sFlt-1 was increased and PIGF reduced (P < 0.001) compared to controls. Serum sEng levels were also increased in pre-eclampsia. Placental sFlt-1 and sEng were significantly higher (P < 0.0001), and PIGF lower (P = 0.008), in pre-eclampsia compared to controls and gestational hypertension. Antihypertensive therapy was associated with a significant fall in serum and placental sFlt-1 and sEng in pre-eclampsia only (P < 0.05). In pre-eclampsia, but not gestational hypertension, treatment was associated with significantly (P < 0.05) lower serum and placental inhibin A and activin A. In women with pre-eclampsia or gestational hypertension, both AP (P < 0.0001 and P < 0.05) and Aix-75 (P < 0.0001 and P < 0.001) were significantly higher than controls. Antihypertensive therapy resulted in a significant fall in both AP and Aix-75 in pre-eclampsia only (P < 0.0001). Anti hypertensive drugs may have an effect on the pathophysiology of pre-eclampsia other than their known anti hypertensive action.

A fluoxetina, um fármaco quiral disponível para uso clínico, como uma mistura racêmica de (S)-(+)-fluoxetina e (R)-(-)-fluoxetina, é a droga mais utilizada no tratamento de estados depressivos durante a gravidez. N-desmetilação de fluoxetina por CYP2D6, CYP2C9 e CYP3A4 produz o seu metabólito ativo, norfluoxetina com os enantiômeros (S)-(+)-e (R)-(-)- norfluoxetina. Os objetivos deste estudo foram avaliar a farmacocinética, distribuição transplacentária e metabolismo da fluoxetina e norfluoxetina, em gestantes saudáveis. Foram avaliadas nove gestantes sem comorbidades. Todas receberam dose única de 20 mg de fluoxetina via oral em duas ocasiões distintas, sendo a primeira com 32 semanas e a segunda no dia do parto. Após a administração do fármaco, foram coletadas amostras seriadas de sangue materno para avaliação da concentração dos enantiômeros da fluoxetina, nos tempos de zero a 672 horas. No dia do parto, após receber a medicação, foram coletadas amostras sanguíneas materna no momento do nascimento, de sangue de vasos umbilicais, espaço interviloso, líquido amniótico para avaliação da transferência placentária. Vinte e quatro horas após o parto, foi coletada uma amostra de 3 mL de leite materno para avaliação de excreção. A análise dos enantiômeros da fluoxetina e norfluoxetina em plasma humano foi realizada por cromatografia líquida de alta eficiência (LC-MS/MS). O método de análise foi desenvolvido e validado de acordo com a RDC 27, ANVISA. As medianas dos parâmetros farmacocinéticos dos enantiômeros (S)-(+)- e (R)-(-)- da fluoxetina foram, respectivamente: Cmax 6,05 vs 5,94 ng/mL, t1/2 ? 1,94 vs 2,33 h, AUC0-? 97,81 vs 209,20 ng.h/mL, Cl/f 1,45 vs 0,66 L/h/kg, Vd/f 19,00 vs 23,25 L/kg. E dos parâmetros farmacocinéticos dos (S)-(+)- e (R)-(-)-norfluoxetina foram, respectivamente: Cmax 6,29 vs 3,29 ng/mL, t1/2 ? 83,48 vs 95,15 h, AUC0-? 942,70 vs 498,6 ng.h/mL. O método para análise dos enantiômeros da fluoxetina e norfluoxetina mostraram limites compatíveis com a aplicação de um estudo clínico envolvendo a administração de uma dose única. Foi observada enantiosseletividade em alguns parâmetros na farmacocinética e transferência placentária da fluoxetina e norfluoxetina em gestantes. / Fluoxetine, a chiral drug available for clinical use as a racemic mixture of (S)-(+)-fluoxetine and (R)-(-)-fluoxetine, is the most widely used drug in the treatment of depressive states during pregnancy. N-demethylation of fluoxetine by CYP2D6, CYP2C9 and CYP3A4 produce its active metabolite norfluoxetine as the enantiomers S-(+) and (R)-(-)-norfluoxetine. The objectives of this study were to evaluate the pharmacokinetics, transplacental distribution and metabolism of fluoxetine and norfluoxetine in healthy pregnant women. A total of nine pregnant women without comorbidities received a single oral dose of 20 mg fluoxetine on two separate occasions, the first in the 32 gestation weeks and the second at the day of delivery. After drug administration during the first sequential samples of maternal blood were collected at time zero until 672 hours. On the day of delivery, after receiving the medication maternal blood sample was collected at birth, umbilical blood vessels, intervillous space, and amniotic fluid sample for evaluation of placental drug transfer. Twenty-four hours after delivery was collected a sample of 3 ml of breast milk for analysis of excretion by this way. The analysis of the enantiomers of fluoxetine and norfluoxetine in human plasma was performed by high-performance liquid chromatography (LC-MS/MS) .The analytical method was developed and validated in accordance with the RDC 27, ANVISA. Median pharmacokinetic parameters of (S)-(+)- and (R)-(-)-fluoxetine enantiomers were: Cmax 6.05 vs 5.94 ng/mL, t1/2 ? 1.94 vs 2.33 h, AUC 0-? 97.81 vs 209.20 ng.hr/mL, Cl/f 1.45 vs 0.66 L/h/kg, Vd/f 19.00 vs 23.25 L/kg. The values of (S)-(+)- and (R)-(-)-norfluoxetine enantiomers were: Cmax 6.29 vs 3.29 ng/mL, t1/2 ? 83.48 vs 95.15 h, AUC 0-? 942.70 vs 498.6 ng.h/mL. Confidence method for sequence analysis of the enantiomers of fluoxetine and its active metabolites showed limits compatible with the application of a clinical study involving the administration of a single dose of pregnant women. Enantioselectivity was observed in some parameters of pharmacokinetics and placental fluoxetine and norfluoxetine transfer in healthy pregnant women.

A Ipomoea carnea é uma planta tóxica amplamente distribuída no Brasil e em outros países tropicais. Durante os períodos de seca esta planta se mantém verde, podendo servir como fonte de alimento para os animais de produção. A intoxicação natural é de caráter crônico e ocorre quando ruminantes particularmente, caprinos ingerem a planta, estes animais desenvolvem, principalmente, sintomatologia de origem nervosa. Dois tipos de princípios ativos tóxicos foram isolados desta planta, um alcalóide nortropânico, as calisteginas B1, B2, B3 e C1 e principalmente o alcalóide indolizidínico, a suainsonina, cujo mecanismo de ação tóxico se estabelece por inibição de duas enzimas a &alpha;-manosidase lisossomal, levando ao acúmulo de oligossacarídeos não metabolizados no interior de lisossomos, promovendo a degeneração vacuolar intracitoplasmática, perda de função e até mesmo morte celular e a manosidase II do Complexo de Golgi, causando alterações na síntese, no processamento e no transporte de glicoproteínas. Histologicamente esta intoxicação é caracterizada pela presença de vacúolos lisossomais no sistema nervoso central (SNC), tireóide, fígado, pâncreas e rins. Recentemente, pesquisas, relativas à toxicidade perinatal desta planta, vêm mostrando que a Ipomoea carnea possui efeitos teratogênicos, em ratos, caprinos e coelhos, porém até o momento não se sabe se a placenta poderia estar envolvida na gênese desta patologia ou se os efeitos deletérios no feto seriam devidos diretamente à passagem transplacentária do princípio ativo tóxico. Portanto o principal objetivo desta pesquisa foi verificar o possível efeito placentotóxico da planta. Assim, o resíduo aquoso final da planta (RAF) foi administrado, via oral, por gavage para ratas Wistar gestantes, nas doses de 1,0; 3,0 e 7,0 g/kg no período do 6º ao 19º dias de gestação, já os animais do grupo controle e peer-feeding, receberam apenas água pela mesma via e período que os animais tratados. Durante o período de tratamento estes animais foram inspecionados diariamente e o consumo de água e ração, bem como o ganho de peso mensurados à cada 3 dias. No final da gestação parte dos animais foram, destinados a secção cesariana, para principalmente avaliação do tecido placentário e os outros animais seguiram a gestação até o nascimento a termo para análise das proles. Dos animais provenientes da secção cesariana, foram coletados os fetos e suas respectivas placentas, sendo estas encaminhadas para análise anatomopatológica, histoquímica (lectinas e TUNEL) e morfométrica, assim como os fetos mensurados quanto ao seu tamanho e peso e avaliados para malformações externas e análise óssea e visceral e realizado o desempenho reprodutivo destas fêmeas. As gestantes que seguiram até o nascimento de suas prole, as quais foram avaliadas quanto ao seu desenvolvimento físico e reflexológico diariamente e nos dias 4, 8, 15 e 22 de lactação, um filhote de cada mãe foi eutanasiado para coleta de fragmentos representativos do fígado, rim, SNC e pâncreas para avaliação histopatológica, este procedimento também foi realizado naquelas mães submetidas a secção cesariana no 20º dia de gestação, bem como nas mães lactantes no 22º dia de lactação. Os resultados obtidos evidenciam claramente o potencial teratogênico produzido pela Ipomoea carnea, visto que tanto os fetos quanto os filhotes apresentaram algumas anomalias congênitas, diminuição do peso ao nascimento e também o retardo na geotaxia negativa. No fígado e nos rins das mães e dos filhotes foi observada a degeneração vacuolar, evidenciando a toxicidade materna e fetal promovida pela planta expostos durante o período gestacional. Um dado importante aqui observado se refere à avaliação do tecido placentário, o qual apresentou algumas alterações histopatológicas, como o espessamento da zona de labirinto e a redução de espessura da zona juncional, porém a degeneração vacuolar não fora observada neste órgão, porém quando realizada a técnica de lectina-histoquímica, foi possível observar o acúmulo de alguns açúcares nas células em diversas regiões da placenta, evidenciando desta forma que este tecido também sofreu injúria promovida pela ação da planta, não sendo mais possível considerar este órgão apenas como um local de passagem para estes princípios ativos tóxicos. / Ipomoea carnea is a toxic plant widely distributed in Brazil and other tropical countries. During periods of drought, animals graze on this plant which grows even in the presence of adverse climatic conditions. After prolonged periods of plant intake, the animals exhibit a variety of clinical signs as depression, general weakness, body weight loss, staggering gait, muscle tremors, ataxia, posterior paresis, and paralysis. Two kinds of toxic principles were isolated from the plant, the nortropane alkaloids calystegines B1, B2, B3 and C1 and mainly the indolizidine alkaloid swainsonine. The latter alkaloid is a potent inhibitor of two distinct intracellular enzymes, the lysosomal &alpha;-mannosidase which results in lysosomal accumulation of incompletely processed oligosaccharides moieties inside vacuoles, which progresses to cellular function loss and, ultimately, to cell death and the Golgi mannosidase II enzyme causes alteration of the N-linked glycoprotein process, modifying the glycoprotein synthesis, processing and carrier. Histologically, cellular vacuolization of Purkinje cells, thyroid follicles, exocrine pancreas, liver and kidney cells have been observed. Recently, many studies in our laboratory have shown that Ipomoea carnea have teratogenic effects in rats, goats and rabbits. However, it is not known yet if the alterations observed in the fetuses are due to alterations in the placenta or if they can be directly related to the transplacental transfer of the active principle. The present study was performed to evaluate the effects of Ipomoea carnea in the placental tissue and in the litter of female rats treated during. Pregnant rats of the experimental groups were treated orally by gavage, once a day from GD6 to GD19, with 1,0; 3,0; 7,0 g/kg of Ipomoea carnea AF. The control and peer-feeding group received tap water by gavage. Total body weight gain, water and food consumption were measured each three days during the experimental period. At the end of pregnancy period some animals were, for cesarean section, mainly for evaluation of placental tissue and the other animals followed the pregnancy until the birth to the term analysis of offspring. From the animals that came from the cesarean section, were collected the fetuses and their placental, those being collected for anatomopathological, histochemistry (lectins and TUNEL) and morphometric analysis, as the fetuses measured about their sizes and weight and assessed to external malformation and bone and visceral analysis and performed the reproductive performance of those females. The pregnants that followed up to the birth of their offspring, which were assessed regarding their physical and reflexology development daily and at days 4, 8, 15 e 22 of lactation, an offspring of each mother was euthanized so representatives fragments of the liver, kidney, SNC and pancreas could be collected for a histopathological assessment, this procedure was also performed at those mothers submitted to the cesarean section at the 20th pregnancy day, as well as at the breastfeeding at the 22nd lactation day. The obtained results clearly show the teratogenic potential produced by the Ipomoea carnea, because both the fetuses as the pups had some congenital anomalies, decrease in birth weight and the delayed negative geotaxis. At both the mother and offsprings liver and kidneys was observed a vacuolar degeneration, showing the maternal and fetal toxicity promoted by the plant exposed during the pregnancy period. An important data noted here refers to the placental tissue assessment, which showed some histopathological alterations, as the labirinth zone thickening and the reduction of the junctional zone thickness, however the vacuolar degeneration was not observed in this organ, although when performed the lectin-histochemistry technique, it was possible to observe the accumulation of some sugars in some cells located at several regions of the placenta, this way showing that this tissue has also suffered some injury promoted by the plant action, not being possible anymore to consider this organs just as a plac of passage for these toxic active principle.

Humans are continuously exposed to complex mixtures of anthropogenic chemicals. This thesis focus on human exposure to persistent organic pollutants (POPs). POPs ability to bioaccumulate and biomagnify together with the extensive historical use of POPs in e.g. agriculture and industry have resulted in detection of these compounds in humans and animals from all over the world. Adverse health effects caused by POPs are of particular concern for newborns and young individuals. The objective of this thesis is to assess human exposure to a selected set of POPs and their metabolites. More specifically, one aim of my thesis is to determine the exposure to polychlorinated biphenyls (PCBs) and in particular their methylsulfonyl and hydroxylated metabolites in humans from a “hot-spot” area of PCB contamination in eastern Slovakia. The maternal transfer of these chemicals is studied. Further, another specific aim is to determine occurrence, levels and, when possible, temporal trends of POPs in children and adults from three developing countries, Nicaragua, Guinea-Bissau and Bangladesh. High concentrations of PCBs and their metabolites are shown in men and women from Michalovce in eastern Slovakia. Placental transfer of methylsulfonyl-metabolites of PCBs and 4,4’-DDE was observed for the first time. Decreasing temporal trends of the majority of POPs are shown in serum from a cohort of policemen from Guinea-Bissau. In contrast, the levels of polybrominated diphenyl ethers (PBDEs) show an increasing time trend. Within five years, decreasing levels of POPs were also shown in children working and living at a waste disposal site in Nicaragua. Children working and living at waste disposal sites in Bangladesh have considerably lower levels of POPs compared to the children from Nicaragua except for 4,4’-DDT and 4,4’-DDE that are present at very high concentrations, indicating ongoing use of technical DDT. There are many studies on levels and trends of environmental pollutants from the developed industrial countries in the world, whereas data from developing countries is still scarce. This thesis contributes to partly fill this data gap since it includes assessments of POPs in children and adults from four countries on four continents. / At the time of doctoral defense, the following papers were unpublished and had a status as follows: Paper 5: Manuscript. Paper 6: Manuscript.

Different species are separated by pre-zygotic reproductive barriers which impede gene flow between them. Rarely, when pre-zygotic barriers break down, interspecific hybrids are produced that display abnormal phenotypes, collectively called hybrid dysgenesis effects. Interspecies hybrid placental dysplasia (IHPD) in the genus Mus is a very consistent X-linked hybrid dysgenesis effect. Reproductive cloning and mutation of the gene Esx1 lead to placental hyperplasias with phenotypic similarities to IHPD. Comparative gene expression analysis of these three different models of placental hyperplasia showed that different mechanisms underlie these placental hyperplasias. We also identified several genes for which roles in placentation had not been studied earlier. We screened five of these genes, Car2, Ncam1, Fbln1, Cacnb3 and Cpe for their functions in placentation. Analysis of the spatio-temporal expression patterns of these genes during mouse placental development showed that they are ectopically expressed in IHPD placentas. Placental phenotype and gene expression was then studied in mice mutant for these genes. Our results show that complicated by the expression of functional counterparts, deletion of these genes failed to produce any consistent phenotype. Incompletely penetrant phenotypes were found in Cacnb3 and Cpe mutants. The Cpe mutant placentas recapitulated some IHPD phenotypes, despite co-expression of Cpd, a functionally redundant gene. Deregulated expression of Cpe and Cpd prior to manifestation of IHPD phenotype indicated that these are causally involved in IHPD and might be speciation genes in the genus Mus. We found that AT24 placentas also exhibit deregulated expression of these genes and could be used as a model to study IHPD. We tried rescuing the AT24 placental phenotype, by decreasing the expression of the over expressed genes. Normalization of transcript levels of these genes did not rescue the AT24 phenotype, thus indicating that up-regulation of these genes is a down-stream event in the generation of IHPD.

A vital factor for foetal development is the nutrient transport at placental level. This is because any disturbances in the maternal compartments, for example due to maternal stress or nutritional status, which will affect foetal development, will involve the foetal-placental barrier. Moreover, numerous studies have linked other factors such as preterm labour as the leading cause of perinatal morbidity and mortality in the developed world. To this date, despite a numerous epidemiological and clinical studies that identify potential risk factors for the mother as well as the foetus, there is no comprehensive analysis at all these levels taken from the same cohort of patients. Our working hypothesis is that for a successful pregnancy certain events at nutritional, biochemical, genetic and molecular level could be tightly linked. Therefore, in this study we followed a “holistic” approach investigating how maternal stress, nutrition, placental mTOR and glucocorticoid receptor (GR) signalling can influence pregnancy outcome. We have decided to map in detail the components of these two signalling pathways as they appear to cross-talk as well as been implicated in stress responses. The largest part of the questionnaire was focused on the nutritional status with questions targeting the maternal dietary habits before, as well as during, pregnancy. The collection of data took place at the Department of Obstetrics and Gynecology, University of Crete Medical School. With regards to this profile, key findings included the significant reduction in the intake of alcohol, caffeine-containing and sugar-containing refreshments, whereas passive smoking during pregnancy stayed the same. Another major finding of this part of the study was the effects of maternal stress on foetal weight and how pregnancy planning was implicated in this complex relation. In our cohort, women with negative attitudes during pregnancy gave birth to infants with significantly lower birth weights (2.5Kg) than those women showing positive or neutral attitudes towards their pregnancy (2.9Kg). We then assessed how maternal stress might affect this signalling cascade using two placental models (BeWo and JEG-3 cell lines) mimicking a stress milieu in vitro. Treatment of these cell lines with cortisol (100nM and 1000nM) significantly downregulated Deptor and upregulated GAS5 at mRNA level. In an attempt to dissect further a potential gene-environment interaction, we have assessed how 4 well-characterised polymorphisms (ThtIII 1, Bcl I, ER22/23EK, N363S) of the GR gene might affect foetal and placental weight. We have demonstrated that only the maternal ThtIII 1 polymorphism was suggestive of a nature-nurture interaction since only in ThtIII 1 II (CC), maternal stress attitude predicts foetal weight-reduction, but not in ThtIII 1 (GC) independent of confounders such as BMI, pregnancy planning or fast food eating during pregnancy. This is the first time that a gene-environment interaction between a common GR polymorphism and foetal weight was noted. Finally, one of the most important findings of our study came from the preclinical studies using placental tissues. Quantitative PCR revealed that the major transcripts in the human placenta are GRα, GAS5 (decoy for GR DNA binding) and Deptor. We have shown for first time that there are marked differences in the relative mRNA abundance of these components between term and preterm labour as well as colocalisation of GRα with GAS5. With regards to placental regulation these data conclusively demonstrate that: a) there is evidence of gene-environment interaction between maternal stress, pregnancy planning, glucocorticoid receptor polymorphisms and foetal weight and b) potential cross-talk of mTOR and glucocorticoid signalling. We propose that measuring maternal stress levels in addition to circulating cortisol and mapping for known GR polymorphisms could become a useful non-invasive tool of diagnostic and prognostic value, with implications for preterm labour.

No description available.

Background: The aim of this thesis was to study the relationship of pre-diagnostic circulating concentrations of sex steroid hormones (androgens, estradiol, 17-hydroxyprogesterone, and progesterone), growth factors (insulin-like growth factor-I (IGF-I), placental growth hormone (GH)), sex hormone binding globulin (SHBG), and anti-Müllerian hormone (AMH) with risk of epithelial ovarian cancer (EOC) overall, and by tumor invasiveness and histology. A longitudinal study was used to assess patterns of hormonal changes during a single pregnancy, and in two consecutive pregnancies. Materials &amp; Methods: A case-control study was nested within the Finnish Maternity Cohort and the Northern Sweden Maternity Cohort. A total of 1 052 EOC cases were identified through linkages with the cancer registries in both countries. For each case, 2-3 controls were selected. Cases and controls were matched on cohort, age and date at blood draw, as well as for parity at blood draw and at diagnosis (n=2 695). Odds ratios (OR) and corresponding 95% confidence intervals [CI] were estimated using conditional logistic regression. The longitudinal study was based on 71 pregnant Finnish women, who donated blood samples in each trimester of pregnancy. Results: Higher androgen concentrations were associated with an increased risk of overall EOC (e.g., testosterone ORT3 vs. T1: 1.56 [1.30-1.87], ptrend&lt;0.0001), while the risk of endometrioid tumors increased with higher estradiol concentrations (ORT3 vs. T1: 2.76 [1.04-7.33], ptrend=0.03). Higher IGF-I was associated with a non-significant decrease in risk for invasive (ORT3 vs. T1: 0.79 [0.62-1.02], ptrend=0.07) and endometrioid tumors (ORT3 vs. T1: 0.55 [0.28-1.07], ptrend=0.07). The inverse association between IGF-I levels and risk of invasive EOC was stronger in analyses limited to women aged &lt;55 years at diagnosis (ORT3 vs. T1: 0.74 [0.57-0.96], ptrend=0.03). No associations were observed between pre-diagnostic progesterone, SHBG, placental GH, and AMH with EOC risk overall, or by tumor invasiveness and histology. The longitudinal study showed that hormone concentrations were more strongly correlated between consecutive trimesters of a pregnancy than between the 1st and 3rd trimesters. Further, 3rd trimester hormone concentrations can be estimated from 1st or 2nd trimester measurements. Conclusion: Higher pre-diagnostic androgens, estradiol, and IGF-I are associated with EOC risk, and associations differ by tumor invasiveness and histology.

The aim was to explore the possibility to diagnose retained placental tissue and other placental complications with 3D ultrasound and to investigate the impact of previous caesarean section on placentation in forthcoming pregnancies. 3D ultrasound was used to measure the volumes of the uterine body and cavity in 50 women with uncomplicated deliveries throughout the postpartum period. These volumes were then used as reference, to diagnose retained placental tissue in 25 women with secondary postpartum haemorrhage. All but three of the 25 women had retained placental tissue confirmed at histopathology. The volume of the uterine cavity in women with retained placental tissue was larger than the reference in most cases, but even cavities with no retained placental tissue were enlarged (Studies I and II). Women with their first and second birth, recorded in the Swedish medical birth register, were studied in order to find an association between previous caesarean section and retained placenta. The risk of retained placenta with heavy bleeding (&gt;1,000 mL) and normal bleeding (≤1,000 mL) was estimated for 19,459 women with first caesarean section delivery, using 239,150 women with first vaginal delivery as controls. There was an increased risk of retained placenta with heavy bleeding in women with previous caesarean section (adjusted OR 1.61; 95% CI 1.44-1.79). There was no increased risk of retained placenta with normal bleeding (Study III). Placental location, myometrial thickness and Vascularisation Index were recorded on 400 women previously delivered by caesarean section. The outcome was retained placenta and postpartum haemorrhage (≥1,000 mL). There was a trend towards increased risk of postpartum haemorrhage for women with anterior placentae. Women with placenta praevia had an increased risk of retained placenta and postpartum haemorrhage. Vascularisation Index and myometrial thickness did not associate (Study IV). In conclusion: 3D ultrasound can be used to measure the volume of the uterine body and cavity postpartum, but does not increase the diagnostic accuracy of retained placental tissue. Previous caesarean section increases the risk of retained placenta in subsequent pregnancy, and placenta praevia in women with previous caesarean section increases the risk for retained placenta and postpartum haemorrhage.

This thesis aims to assess the human health impact of exposure to estrogenic compounds from the diet. A multi-disciplinary approach is taken to address various aspects of this issue. An introduction to xenoestrogens, including international research priorities, wildlife and human health effects, mechanisms of action, structure activity relationships and additivity of estrogenic effects is provided as background information. An assessment of exposure to a range of naturally occurring and synthetic estrogenic compounds found in food is derived in Chapter 2. The assessment combines new and existing data on food concentration, food consumption and serum levels for each xenoestrogen. Exposure is combined with relative estrogenic potency data from published bioassasy data to estimate risk relative to normal circulating levels of estradiol. Assuming additivity of xenoestrogens, for an average New Zealand male and for post-menopausal women, xenoestrogens in the diet contribute an additional 12-90% of estrogenicity above normal circulating levels. For a pre-menopausal female, the contribution from the diet represents in the order of an additional 2%. The level of exposure determined in this thesis would seem to be of pharmacological relevance, especially for men with low levels of estrogen and for post-menopausal women. Bisphenol A (BPA) is an important monomer used in the manufacture of epoxy resins for internal food can linings. A survey of the BPA content of a range of 80 canned foods available to the New Zealand consumer was undertaken and the results used in the exposure and risk assessments. BPA was detected in all foods analysed except soft drinks, at concentrations ranging from <10-29 µg/kg, except for individual samples of tuna, corned beef and coconut cream that were 109, 98 and 191 µg/kg respectively. None, of over 4000 individual exposure scenarios, exceeded the temporary Tolerable Daily Intake (TDI) of 10 µg/kg body weight per day set by the Scientific Committee on Food in 2002. Intestinal microflora influence the bioavailability of the naturally occurring xenoestrogens genistein and daidzein that contribute significantly to total estrogenicity from the diet. The degradation of genistein and daidzein by the faecal microfloral of 5 human subjects was variable and unpredictable between individuals and within an individual. These findings have important implications for the promotion and prescription of soy foods and supplements for disease prevention and health benefits. The "yeast assay" is one of a number of methods available to measure estrogenicity. This assay was established and validated. In utero exposure to estrogenic compounds at critical periods of sexual differentiation and endocrine development may imprint for health effects observed later in life. Placental transfer of estrogenicity, from 17β-estradiol was studied using the human placental perfusion model and the yeast assay. The placenta provides a protective barrier to the transfer of estrogenicity. Experiments with genistein showed that 5-15% placental transfer occurred, suggesting that in utero exposure might be in the order of 10% of maternal exposure. The thesis concludes with consideration of a genomic approach to substantiate, or refute, the mechanistic link between exposure to xenoestrogens and claimed human health effect. Such an approach offers exciting opportunity to clarify the mode of action of the synthetic versus the naturally occurring xenoestrogens, to confirm or dispute additivity of effect that is an important premise of the exposure assessment, to identify key genes involved in the many possible health effects and thence risk to the individual from dietary exposure to xenoestrogens.