Introdução: A predição do prognóstico neonatal de fetos com hérnia diafragmática congênita (HDC) é um dos principais desafios na Medicina Fetal. A estimativa do volume pulmonar fetal pela ressonância nuclear magnética (RNM) correlaciona-se significativamente com o prognóstico neonatal. Recentemente, foi introduzida a técnica de rotação da imagem multiplanar (VOCALTM) de ultra-sonografia em três dimensões (US-3D), a qual tornou possível estimar o volume pulmonar fetal em casos com HDC. Objetivos: Estimar o volume pulmonar, pela US-3D através da técnica rotacional, em fetos com HDC isolada e comparar com a curva previamente descrita pelo mesmo autor; correlacionar o volume pulmonar fetal total com o prognóstico neonatal; avaliar a acurácia da técnica de rotação em medir o volume pulmonar fetal; e, avaliar outros marcadores ultra-sonográficos clássicos de prognóstico neonatal. Métodos: Este estudo prospectivo foi realizado no período de fevereiro de 2002 a Outubro de 2003 na Maternidade Necker-Enfants Malades, Université de Paris V-Paris, França, em 30 fetos com HDC entre 23 e 36 semanas de gestação. Cada gestante era submetida a um único exame de US-3D, sendo utilizada a técnica de rotação da imagem multiplanar (VOCALTM) para estimar o volume pulmonar fetal. Oito fetos nasceram pós interrupção terapêutica da gestação de acordo com as leis francesas. O volume pulmonar de cada feto (volume observado) foi comparado com a curva padão de nromalidade descrita previamente, sendo calculada a relação entre volumes observado/esperado, a qual foi comparada com a evolução neonatal. Além disso, foram avaliados outros fatores prognósticos clássicos, como: presença de fígado herniado, gravidade do desvio do mediastino, presença de polihidrâmnio, lado da lesão, relação ventrículo esquerdo/ventrículo direito e a relação área do pulmão contralateral/circunferência cefálica (SPC/CC). Foram comparadas também as variações intra- e inter-operador, e a acurácia da ultra-sonografia em estimar o volume pulmonar fetal após a autópsia dos 8 casos em que a gestação foi interrompida. Resultados: Redução importante do volume pulmonar foi observada em fetos com HDC quando esses valores foram distribuídos na curva padrão de normalidade previamente descrita. A relação entre volumes observado/esperado foi significativamente menor nos 12 casos que evoluíram a óbito (mediana= 0,30; variação= 0,12-0,66) em comparação com os 10 sobreviventes (mediana= 0,40; variação= 0,33-0,66; p= 0,017). Dentre outros fatores prognósticos, apenas a relação SPC/CC associou-se significativamente com os resultados neonatais. A predição de óbito neonatal e de sobrevida foi de 90% (9/10) e 75% (9/12) pelo volume pulmonar estimado pela US-3D e de 80% (8/10) e 66,7% (4/8) pela relação SPC/CC estimada pela US-2D, respectivamente. As variações intra- e inter-operadoras foram respectivamente de 0,78cm³ e 0,41cm³. Boa acurácia do método foi observada no presente estudo (84,86%). Conclusões: Em casos com HDC isolada, a estimativa do volume pulmonar fetal pela US-3D, utilizando a técnica rotacional, correlacionou-se significativamente com a evolução neonatal. A relação SPC/CC também se associou significativamente com os resultados neonatais / Introduction: Predicting neonatal outcome in fetuses with congenital diaphragmatic hernia (CDH) is one of the main challenges in Fetal Medicine. Fetal lung volume estimated by magnetic resonance imaging (MRI) associated significantely with neonatal outcome. Recently, the rotationa technique (VOCALTM) on threedimensional ultrasonography (3DUS) was introduced, which allows estimating fetal lung in fetuses with CDH. Objectives: To assess fetal lung volumes by 3DUS using the rotational technique (VOCALTM) in fetuses with isolated CDH, and to plot these values in the nomogram previously described by the same author; to correlate fetal lung volumes with neonatal outcome in cases with CDH; to evaluate the accuracy of 3DUS in estimating fetal lung volumes; and, to evaluate the classical prognostic factors in cases with CDH. Patients and Methods: From Febuary 2002 to October 2003, a prospective study was conducted in Maternité-Hôpital Necker Enfants Malades - Université de Paris V - France, in which 3D- ultrasonographic lung volumes were estiamted in 30 fetuses with isolated CDH 23 and 36 weeks of gestation. Each case was submitted to 3D-ultrasound examination once and 3Dvolumetric measurements were obstained by the technique of rotation of the multiplanar imaging (VOCALTM). Termination of pregnancy was perfromed in 8 cases according to the French law. Observed lung volume in each fetus with isolated CDH was compared to the expected fetal lung for specific gestational age determinated by the nomogram previously described. The observed/expected fetal lung volume was then calculated for each case and correlated with neonatal outcome. Besides,other classical sonographic prognostic were evaluated such as: hydramnios, herniated liver, herniated stomach, lung-over- head ratio, severe mediastinal shift and decreased left/right ventricles ratio. Intra- and inter-operator variabilities were also evaluated, as well as the accuracy of 3D- ultrasound in estimating fetal lung volumes. Results: Observed fetal lung volumes were extremely lower in fetuses with CDH when these values were ptotted in the nomogram of fetal lung volume against gestational age. The observed / expected fetal lung volume ratio was significantly downshifted in 12 cases with CDH who died (median: 0.30, range: 0.12-0.66) compared with 10 suvivors (median: 0.40, range: 0.33-0.66, p= 0,017). Among the other prognostic factors, only the LOHR associated significantly with neonatal outcome. Predicting neonatal deaths and neonatal survivals was 90% (9/10) and 75% (9/12) by fetal lung volume on 3DUS whilst it was 80% (8/10) and 66.7% (4/8) on 2DUS, respectivelly. Intra- and inter-variabilities were 0.78cm³ and 0.41cm³ in cases with CDH, respectively. Good accuracy of this method in estimating fetal lung volume was observed (84.86%). Conclusions: In cases with isolated CDH, fetal lung volume estimated by 3D-ultrasonography using the rotational technique corretated significantly with neonatal outcome. LOHR also associated significantly with neonatal outcome

Ausgehend von einer unspezifischen bakteriellen Infektion kann es während der Schwangerschaft zu einer Infektion der Fruchthöhle kommen. Das volle Bild dieser Art von Infektionen wird Amnioninfektionssyndrom genannt. Die Infektion der Fruchthöhle bedroht Mutter und Kind und die sofortige Entbindung würde ein rasches Abklingen der Infektion des Uterus herbeiführen. Auf der anderen Seite würde häufig eine Entbindung zu einem Zeitpunkt induziert, da das Kind zusätzlich zur Infektion durch die Unreife bedroht ist. Aus der Diagnostik heraus wird die Entscheidung über konservatives oder progressives Vorgehen getroffen. Es stellen sich folgende Fragen: 1. Sind die präpartal erhobenen klinischen Zeichen eines Amnioninfektionssyndromes relevant in der Diagnostik einer konnatal erworbenen neonatalen Infektion? 2. Sind die immunkompetenten Zellen des Neugeborenen in der Lage, inflammatorische Zytokine zu produzieren? 3. Gibt es lösliche Faktoren im Nabelschnurblut, die die Diagnostik einer Infektion des Neugeborenen entscheidend verbessern und die einen Zusammenhang mit einer Infektion der Plazenta aufweisen? 4. Besteht ein Zusammenhang zwischen der präpartalen klinischen Symptomatik eines Amnioninfektionssyndromes und den infektionsabhängigen löslichen Parametern im Nabelblut? Es wurden zwei prospektive Studien zur Beantwortung der Fragestellung durchgeführt. Im Rahmen der ersten Studie wurden 511 Fälle analysiert. Es fand eine Evaluierung der präpartalen klinischen Parameter bezogen auf das Ereignis neonatale Infektion und histologisch gesicherte Infektion der Plazenta statt. Die Konzentrationen der Zytokine Interleukin-6, Interleukin-8, Tumornekrosefaktor-a, G-CSF und der laborchemischen Parameter C-reaktives Protein und Procalcitonin wurde im Nabelschnurblut direkt nach der Geburt bestimmt. Diese Konzentrationen wurden in Bezug gesetzt zu klinischen Anzeichen einer Infektion des Neugeborenen und histologischen Zeichen einer Infektion der Plazenta. Außerdem wurden sie in Bezug gesetzt zu den präpartalen Symptomen eines Amnioninfektionssyndromes. In einer zweiten Studie wurden 42 Fälle analysiert. Mittels Durchflußzytometrie wurden Zellen aus Vollblut isoliert. Isoliert wurde die T-Zellpopulation CD 4 und CD 8 der Lymphozyten untersucht Eine intrazytoplasmatische Zytokinbestimmung nach Stimulation mit Ionomycin und Phorbol-12,13-Dibutyrat unter Verwendung von Monensin wurde durchgeführt. Bestimmt wurde die intrazytoplasmatische Zytokinfreisetzung der Zytokine Interleukin-6 und Interleukin-8. Die präpartalen Symptome mütterliche Temperaturerhöhung, mütterliche CRP-Erhöhung und fetale Tachykardie haben nur eine begrenzte Aussagekraft im Hinblick auf das Ereignis Neonatale Infektion. Während für die präpartal festgestellte fetale Tachykardie und die mütterliche Temperaturerhöhung eine Sensitivität für die "Neonatale Infektion" von 28,6 % bestimmt wurde, liegt dieser Wert für die präpartale mütterliche CRP-Erhöhung bei 45,5% deutlich höher. Die aus dem Nabelblut isolierten Lymphozyten sind in der Lage, auf eine unspezifische Stimulation hin, Interleukin-8 und Interleukin-6 zu produzieren. Signifikant höher liegt die Sekretion an Interleukin-6 dann, wenn die Kinder mit dem Verdacht auf eine peripartale Infektion geboren wurden oder wenn infektionsrelevante Ereignisse vor der Geburt aufgetreten waren. Von den im Nabelschnurblut untersuchten löslichen Parametern fällt auf, daß Procalcitonin mit einer Sensitivität von 93,3% und einer Spezifität von 73,1% ein sehr zuverlässiger Parameter zur Diagnostik einer neonatalen Infektion darstellt. Mit einer Sensitivität von 58,3% und einer Spezifität von 90,4% hebt sich auch der hochsensitive Nachweis des CRP im Nabelblut noch deutlich von den herkömmlich verwendeten Parametern ab. Nur eingeschränkte Aussagekraft auf das Ereignis "Neonatale Infektion" hat die Bestimmung des Interleukin-6. Die kombinierte Betrachtung der präpartal erhobenen klinischen Parameter fetale Tachykardie, mütterliche Temperaturerhöhung und mütterliche CRP-Erhöhung verbessert die vorgeburtliche Diagnostik einer intrauterin bestehenden Infektion deutlich. Der Nachweis der intrazellulären Interleukin-6- und Interleukin-8-Produktion durch neonatale Lymphozyten zeigt die Fähigkeit der zellvermittelten Immunität des Neugeborenen schon vor der Geburt auf bakterielle Infektionen reagieren zu können. Die differenzierte Reaktionsfähigkeit zeigt sich in der gesteigerten Interleukin-6-Syntheseleistung in all den Fällen, die in die "Infektionsgruppe" eingeschlossen waren. Von den löslichen Infektparametern im Nabelblut sticht das Procalcitonin als sehr zuverlässiger Marker sowohl einer Infektion des Neugeborenen als auch der histologisch gesicherten Infektion der Plazenta hervor. Auch Interleukin-6 sollte bestimmt werden. Die nachgewiesene Möglichkeit des Neugeborenen, inflammatorische Zytokine in hohen Konzentrationen als Antwort auf eine bakterielle Invasion produzieren zu können, scheint auch die Gefahr in sich zu bergen, durch eben dieses Interleukin-6 eine cerebral schädigende Reaktion zu erfahren. Zur Abschätzung dieses Risikos ist eine Bestimmung des Interleukin-6 im Nabelschnurblut empfehlenswert. / Starting with a nonspecific bacterial infection, during the pregnancy an infection of the amnion can occur. The full expression of this kind of infections is called chorioamnionitis. The infection of the amnion endangers mother and child, and the immediate delivery would produce a quick subsidence of the uterine infection. On the other hand a delivery would frequently be induced at a time when in addition to the infection the child is endangered by prematurity. Out of the diagnostic investigation the decision on conservative or progressive procedure is made. Following questions arise: 1. Are the prepartally ascertained clinical signs of a chorioamnionitis relevant in the diagnosis of a connatally acquired neonatal infection? 2. Are the immunocompetent cells of the neonate able to produce inflammatory cytokines? 3. Are there soluble factors in the cord blood which decisively improve the diagnosis of an infection of the neonate and show a correlation with an infection of the placenta? 4. Is there a correlation between the prepartal clinical symptoms of an amniotic infection syndrome and the infection-dependent soluble parameters in cord blood? Two prospective studies were carried out in order to answer the question. Within the scope of the first study 511 cases were analyzed. An evaluation of the prepartal clinical parameters related to the occurence neonatal infection and histologically established infection of the placenta took place. The concentrations of the cytokines interleukin-6, interleukin-8, tumor necrosis factor-a, G-CSF and the lab-chemical parameters C-reactive protein and procalcitonin were measured in the cord blood directly after birth. These concentrations were related to clinical signs of an infection of the neonate and histological signs of an amniotic infection. In addition they were related to the prepartal symptoms of an amniotic infection syndrome. In a second study 42 cases were analyzed. Using flow cytometry cells were isolated from whole blood. The T cell population CD 4 and CD 8 of lymphocytes was isolatedly examined. An intracytoplasmic cytokine analysis after stimulation with Ionomycin and phorbol-12,13-dibutyrate using Monensin was performed. The intracytoplasmic cytokine release of interleukin-6 and interleukin-8 was determined. The prepartal symptoms maternal elevation of temperature, maternal CRP increase and fetal tachycardia are only poor prognostic predictors with regard to the occurence neonatal infection. While for the prepartally ascertained fetal tachycardia and the maternal rise of temperature a sensitivity for the "neonatal infection" of 28.6% was determined, for the prepartal maternal CRP increase this value is clearly higher with 45.5%. The lymphocytes isolated from cord blood are able to produce interleukin-8 and interleukin-6 on account of a nonspecific stimulation. The interleukin-6 secretion is significantly higher if the children were born with the suspicion of a peripartal infection or if infection-relevant occurences were arisen before birth. Regarding the soluble parameters examined from the cord blood, it is remarkable that with a sensitivity of 93.3% and a specificity of 73.1% procalcitonin shows to be a very reliable parameter for diagnosis of a neonatal infection. With a sensitivity of 58.3% and a specificity of 90.4% also the high sensitive detection of CRP in cord blood stands out clearly from the conventionally used parameters. The determination of interleukin-6 has only a limited meaningfulness with regard to the occurence "neonatal infection". The combined contemplation of the prepartally measured clinical parameters fetal tachycardia, maternal rise of temperature and maternal CRP elevation clearly improves the antenatal diagnosis of an intrauterine infection. The detection of intracellular interleukin-6 and interleukin-8 production through neonatal lymphocytes shows the capability of cell-mediated immunity of neonate to react to a bacterial infection before birth. The differentiated reactivity is shown in the increased interleukin-6 synthesis in all those cases which were included in the "infection group". Among the soluble infection parameters in cord blood the procalcitonin stands out as a very reliable marker of neonatal infection as well as the histologically established infection of the placenta. Interleukin-6 should also be determined. The proved possibility of the neonate to produce inflammatory cytokines in high concentrations as an answer to a bacterial invasion seems also to involve the risk to experience a cerebrally damaging reaction through exactly this interleukin-6. For estimation of this risk, an interleukin-6 analysis in cord blood is recommendable.

Die dreidimensionale Sonographie ermöglicht die Beobachtung der menschlichen Morphogenese in utero. Ziel der vorliegenden Untersuchung war die Evaluierung der Darstellung der embryonalen und frühen fetalen Oberflächenmorphogenese mittels transvaginaler 3D-Sonographie unter Anwendung eines neuen Verfahrens (3D-Cut) zur Sichtoptimierung. Fünf Schwangere mit datierten Embryonen wurden longitudinal zwischen der 4. und 12. Woche p.m. transvaginal sonographiert. Die Untersuchungen wurden mit einem 3D-Ultraschallgerät der Firma Kretztechnik (VoluSonâ 530D MT) unter Verwendung einer 3D-Transvaginalsonde (5-8 MHz) durchgeführt. Die 3D-Daten wurden unter Einsatz des 3D-Cut-Verfahrens zu dreidimensionalen Oberflächenmodellen der Embryonen und Feten verarbeitet und mit embryologischen Präparaten gleichen Gestationsalters sowie den Ergebnissen bisheriger 3D-sonoembryologischer Studien verglichen. Die Darstellung der embryonalen und fetalen Oberflächenmorphologie gelang kontinuierlich ab der 6. Woche p.m.. Im chronologischen Verlauf zeigten die beobachteten Embryonen und Feten einen umfangreichen Gestaltwandel von einer C-förmigen Struktur ohne sonographisch fassbare Oberflächendetails hin zu einem Individuum von menschlicher Gestalt. Unter Berücksichtigung der sonographischen Auflösungsgrenzen war eine hohe Übereinstimmung zwischen den sonographischen Oberflächenmodellen und den korrespondierenden embryologischen Präparaten zu verzeichnen. Mit den Ergebnissen 3D-sonoembryologischer Voruntersuchungen ergab sich ebenfalls eine gute Korrelation. Die angewandte sonographische Methode ermöglicht auf nichtinvasive Weise eine detaillierte, systematische dreidimensionale Darstellung von Embryonen und frühen Feten in utero und vermittelt so wertvolle Informationen, die der embryologischen Forschung in dieser Weise bisher nicht zugänglich waren. / Three-dimensional sonography allows the observation of the human morphogenesis in utero. The objective of the presented study was the evaluation of the demonstration of embryonic and early fetal surface morphogenesis by means of transvaginal 3D-sonography using a new procedure (3D-Cut) for the optimization of image quality. Five pregnant women with dated embryos were examined longitudinally by transvaginal 3D-sonography between 3 and 11 completed weeks p.m.. The examinations were performed with a 3D-Ultrasoundmachine (VoluSonâ 530D MT) developed by Kretztechnik (Zipf/Austria) using a transvaginal 5-8 MHz-3D-transducer. The 3D-data were processed to three-dimensional surface models of the embryos and fetuses using the 3D-Cut-procedure and compared with embryologic specimens of corresponding gestational age as well as with the results of prior 3D-sonoembryological studies. Embryonic and early fetal surface morphology could be demonstrated continuously starting from 5 completed weeks p.m.. The observed embryos and fetuses showed an extensive morphological change from a C-shaped structure without sonographically detectable surface details to an individual of human shape. With consideration of the limited sonographic resolution a high agreement between sonographic surface models and the corresponding embryologic specimens was registered. A good correlation was also found with the results of prior 3D-sonoembryological studies. The applied sonographic method allows in a noninvasive way a detailed systematic three-dimensional demonstration of embryos and early fetuses in utero and provides thus valuable information, which was not accessible to embryological research in this way so far.

目前廣泛應用于胎兒醫學的唐氏綜合症篩查法，即結合早孕期胎兒頸項透明層的超聲檢查，及母體血清生化指標的綜合篩查法。頸項透明層是指在早孕期利用超聲檢測到的胎兒頸后的皮下積水，其作為預測胎兒異常的一項重要“軟指標，其臨床意義，尤其是與胎兒染色體異常及器官結構異常之間的關係，逐漸得到深入的認識，但其形成機制尚未明確。現在已知有一百餘種畸形及遺傳綜合征與胎兒頸項透明層增厚相關，但其染色體異常譜系，尤其是亞顯微的染色體異常仍有待明確。大部分頸項透明層增厚但核型正常的胎兒預後良好，但約3-10%的這部分胎兒會伴有畸形或出生后的神經智力發育缺陷。而傳統核型分析無法檢測到亞顯微的染色體異常，從而無法判斷這部分核型正常卻伴有缺陷的胎兒是否因為這類染色體異常而致病。 / 微陣列比較基因組雜交芯片作為檢測兒童發育遲緩者及器官結構異常原因的重要手段已廣泛應用于臨床。在染色體核型正常的胎兒中，若伴有器官結構異常的胎兒，5-12%被檢出與該畸形相關的微缺失及微重複；若僅伴有孕婦高齡或唐氏篩查高危，則微缺失及微重複檢出率約1%。 / 該課題旨在研究頸項透明層增厚但核型正常的胎兒中，染色體拷貝數變異發生的頻率及頻譜；評估微陣列比較基因組雜交芯片在協助臨床判斷胎兒預後中的作用。因此，我們開展該多中心隊列研究，通過納入449例頸項透明層厚度≧3.5 mm但正常核型胎兒的，檢測其染色體拷貝數變異，監測并記錄其圍產、產後及新生兒期情況。微陣列比較基因組雜交芯片總共檢出2.8%的異常拷貝數變異，其大小範圍為0.1 kb至18Mb。在伴有器官結構異常的胎兒組中，異常拷貝數變異檢出率達7.8%。對於頸項透明層厚度≧4.0 mm的胎兒，異常拷貝數變異檢出率可達7.3%。 / 對於頸項透明層增厚的胎兒，致病拷貝數變異暫未發現特定的頻譜。但，該研究中發現重複的致病拷貝數變異，如22號染色體長臂1區1帶的微重複或微缺失，2號染色體長臂2區2帶的微缺失。未在3號、7號、12號、13號、18號、20號、21號或Y染色體上發現與胎兒頸項透明層增厚相關的致病拷貝數變異。 / 頸項透明層增厚的胎兒79.3%預後良好；若經微陣列比較基因組雜交芯片未檢出致病拷貝數變異，則81.2%預後良好。如果僅頸項透明層增厚不伴有結構異常的胎兒，經微陣列比較基因組雜交芯片未檢出致病拷貝數變異，則93.5%預後良好。 / 綜上所述，微陣列比較基因組雜交芯片顯著提高了致病拷貝數變異的檢出率。可考慮將微陣列比較基因組雜交芯片作為頸項透明層厚度≧4.0 mm的胎兒染色體異常檢查的首要方法。對於僅頸項透明層增厚不伴有結構異常的胎兒，且經微陣列比較基因組雜交芯片未檢出致病拷貝數變異，絶大部分預後良好。對於頸項透明層增厚的胎兒，致病拷貝數變異暫未發現特定的頻譜，但發現重複出現的致病拷貝數變異。通過初步的基因本體分析及基因通路分析，神經嵴細胞的分化遷徙功能異常可作為今後研究頸項透明層增厚的病理生理機制的方向。 / Measurement of nuchal translucency (NT) has been recognized as a sensitive marker for fetal chromosomal disorders for more than a decade, and is presently used as a routine first-trimester screening test. Although over 100 abnormalities and genetic syndromes have been reported to be associated with increased NT, these associations have not been fully explored and the relevant spectrum of associated submicroscopic chromosomal abnormalities has not been sufficiently investigated. The majority of euploid fetuses with increased NT have a good outcome, but around 3-10% of fetuses present with structural or neurodevelopmental abnormalities postnatally. A range of genetic syndromes has been reported, many of which are linked to submicroscopic chromosomal abnormalities that are typically missed by conventional karyotyping. / Microarray-based comparative genomic hybridization (arrayCGH) has been applied as the first-tier diagnostic tool for the evaluation of developmental delay and structural malformations in children. In fetuses with a normal karyotype, microarray analysis revealed clinically relevant deletions or duplications in 5-12% with a structural anomaly and in about 1% of those whose indications were advanced maternal age or positive screening results. / The objectives of this study were to delineate the frequency and spectrum of pathogenic chromosome copy number variants (CNVs) among fetuses with increased NT and normal karyotype; to evaluate the role of arrayCGH to predict the prognosis of the high NT fetuses; to explore the genotype-phenotype correlations of increased NT. Therefore, a multi-centre cohort of 449 fetuses with NT ≧3.5 mm and normal karyotype were further investigated by arrayCGH. Antenatal surveillance, pregnancy outcome and paediatric follow up were documented. ArrayCGH detected abnormal CNVs in 2.8% (14 of 449) of the fetuses with high NT; the size of CNVs ranged from 0.1 kb to 18Mb. Among fetuses with major congenital abnormalities the incidence of abnormal CNV reached 7.8% (4 of 51). By adjusting the NT to ≧4.0 mm as the referral indication, 7.3% (14 of 192) of the fetuses would have abnormal arrayCGH results. The spectrum of pathogenic CNVs found associated with increased NT was diverse. However, there were recurrent ones such as the deletions or duplications at chromosomal region 22q11, and deletions in ZEB2. There was no pathogenic CNV related with increased NT found in chromosomes 3, 7, 12, 13, 18, 20, 21, or Y. The total normal outcome rate of euploid fetuses with an increased NT was 79.3%; for fetuses with normal arrayCGH results 81.2% had a normal outcome. In fetuses with isolated increased NT, normal arrayCGH results predict a favorable prognosis of 93.5%. / In conclusion, arrayCGH significantly increased the diagnostic yield of pathogenic CNVs. In clinical practice arrayCGH may be considered as the first tier investigation in fetuses with an increased NT more than 4.0 mm. In cases with an isolated increased NT with normal arrayCGH results the pregnancy outcome is likely to be favorable. The spectrum of abnormal CNVs found by arrayCGH is diverse but there are recurrent cases such as del/dup 22q11 and del ZEB2. Our preliminary gene ontology and pathway analysis showed that gene pathways related to neural crest cells may be considered as a future study for physiopathologic mechanisms of NT. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Huang, Jin. / Thesis (Ph.D.) Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 106-120). / Abstracts also in Chinese.

Chan, Wing Lung. / Thesis (M.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 111-130). / Abstracts in English and Chinese. / Title --- p.i / Acknowledgements --- p.ii / Table of Content --- p.iii / List of Tables --- p.viii / List of Figures --- p.xi / List of Graphs --- p.xii / Abbreviations --- p.xiv / Abstract --- p.xv / Abstract (Chinese) --- p.xvii / Chapter Chapter 1: --- General Introduction / Chapter 1.1 --- Diabetes Mellitus --- p.2 / Chapter 1.1.1 --- Type 1 diabetes mellitus --- p.3 / Chapter 1.1.2 --- Type 2 diabetes mellitus --- p.4 / Chapter 1.1.3 --- Gestational diabetes mellitus --- p.5 / Chapter 1.2 --- Diabetic Pregnancy --- p.6 / Chapter 1.2.1 --- Incidence of congenital malformations in diabetic pregnancy --- p.6 / Chapter 1.2.2 --- Long term complications in the infant of diabetic mother --- p.7 / Chapter 1.3 --- Hyperglycemia --- p.7 / Chapter 1.4 --- Oxidative Stress --- p.8 / Chapter 1.4.1 --- Oxidative stress and antioxidant enzymes --- p.8 / Chapter 1.4.2 --- Cellular function of oxidative stress --- p.9 / Chapter 1.4.3 --- Adverse effects of excess oxidative stress during embryogenesis --- p.9 / Chapter 1.5 --- Retinoic Acid --- p.10 / Chapter 1.5.1 --- Function of RA during embryonic development --- p.10 / Chapter 1.5.2 --- RA synthesis and degradation --- p.10 / Chapter 1.5.3 --- Mechanisms of retinoic acid signaling : --- p.12 / Chapter 1.5.4 --- Developmental genes regulated by RA --- p.12 / Chapter 1.6 --- Strategy of the Thesis --- p.14 / Chapter Chapter 2: --- General Materials and Methods / Chapter 2.1 --- Animals --- p.17 / Chapter 2.2 --- Induction of Diabetes --- p.17 / Chapter 2.3 --- Mating Methods --- p.18 / Chapter 2.3.1 --- Mice --- p.18 / Chapter 2.3.2 --- Rats --- p.18 / Chapter 2.4 --- Whole Mount In Situ Hybridization --- p.19 / Chapter 2.4.1 --- Synthesis of DNA plasmids and riboprobes --- p.19 / Chapter 2.4.1.1 --- Mini-scale preparation of plasmid DNA --- p.19 / Chapter 2.4.1.2 --- Linearization of DNA plasmid --- p.20 / Chapter 2.4.1.3 --- In vitro transcription and labeling --- p.21 / Chapter 2.4.2 --- Fixation and dehydration of embryos --- p.22 / Chapter 2.4.3 --- Hybridization with RNA probes --- p.23 / Chapter 2.4.4 --- Post-hybridization wash --- p.24 / Chapter 2.4.4.1 --- Pre-absorption of anti-DIG antibody --- p.25 / Chapter 2.4.4.2 --- Embryo powder preparation --- p.25 / Chapter 2.4.5 --- Post antibody wash and signal development --- p.25 / Chapter 2.5 --- Real-time Quantitative Reverse Transcription-Polymerase Chain Reaction (RT-PCR) --- p.26 / Chapter 2.5.1 --- Sample collection and storage --- p.26 / Chapter 2.5.2 --- Total RNA extraction --- p.27 / Chapter 2.5.3 --- Reverse transcription --- p.28 / Chapter 2.5.4 --- Quantitative real-time PCR --- p.28 / Chapter 2.5.5 --- Preparation of cDNA standards for real-time PCR --- p.29 / Chapter 2.6 --- RA-responsive Cell Line --- p.29 / Chapter 2.6.1 --- Cell culture --- p.30 / Chapter 2.6.2 --- Seeding 96-well plate with RA-responsive cells --- p.31 / Chapter 2.6.3 --- Applying samples to 96-well plate coated with RA-responsive cells --- p.31 / Chapter 2.6.4 --- β-galactosidase staining --- p.32 / Chapter 2.7 --- Separation of Protein Isoforms by Isoelectric Focusing (IEF) --- p.33 / Chapter 2.7.1 --- Preparing protein samples for IEF --- p.33 / Chapter 2.7.2 --- Isoelectric focusing --- p.33 / Chapter 2.7.3 --- IEF native gel staining --- p.34 / Chapter 2.7.4 --- Locating three retinaldehyde dehydrogenase (Raldh) isoforms --- p.35 / Chapter 2.8 --- In Vitro RA Synthesizing Reaction --- p.36 / Chapter Chapter 3: --- Effect of Maternal Diabetes on Retinoic Acid Synthesis in the Mouse Embryo / Chapter 3.1 --- Introduction --- p.38 / Chapter 3.2 --- Experimental Design --- p.41 / Chapter 3.3 --- Materials and Methods --- p.42 / Chapter 3.3.1 --- Sample collection --- p.42 / Chapter 3.3.1.1 --- Criteria for selecting embryos at the same developmental stage --- p.42 / Chapter 3.3.1.2 --- Sample collection for in situ hybridization --- p.42 / Chapter 3.3.1.3 --- Sample collection for real-time quantitative RT-PCR --- p.43 / Chapter 3.3.1.4 --- Sample collection for in vitro RA synthesizing reaction --- p.44 / Chapter 3.3.2 --- Statistical analyses --- p.45 / Chapter 3.4 --- Results --- p.46 / Chapter 3.4.1 --- "Comparison of the in situ expression pattern of Raldh 1, Raldh2 and Raldh3 between embryos of diabetic and non-diabetic mice" --- p.46 / Chapter 3.4.1.1 --- In situ hybridization patterns of Raldh 1 --- p.46 / Chapter 3.4.1.2 --- In situ hybridization patterns of Raldhl --- p.46 / Chapter 3.4.1.3 --- In situ hybridization patterns of Raldh3 --- p.47 / Chapter 3.4.2 --- "Comparison of the relative expression level of Raldh 1, Raldh2 and Raldh3 between embryos of diabetic and non-diabetic mice at different developmental stages" --- p.48 / Chapter 3.4.2.1 --- Relative expression levels of Raldh 1 --- p.50 / Chapter 3.4.2.2 --- Relative expression levels of Raldh2 --- p.50 / Chapter 3.4.2.3 --- Relative expression levels of Raldh3 --- p.51 / Chapter 3.4.3 --- Comparison of the in vitro RA synthesizing activity of Raldh 1 Raldh2 and Raldh3 enzymes between embryos of diabetic and non-diabetic mice at different developmental stages --- p.52 / Chapter 3.5 --- Discussion --- p.55 / Chapter Chapter 4: --- Effect of Hyperglycemia on Retinoic Acid Synthesis / Chapter 4.1 --- Introduction --- p.59 / Chapter 4.2 --- Experimental Design --- p.61 / Chapter 4.3 --- Materials and Methods --- p.64 / Chapter 4.3.1 --- Phlorizin treatment --- p.64 / Chapter 4.3.2 --- Whole rat embryo culture --- p.64 / Chapter 4.3.3 --- Preparation of rat serum --- p.65 / Chapter 4.3.4 --- In situ hybridization --- p.66 / Chapter 4.3.5 --- Real-time quantitative RT-PCR --- p.66 / Chapter 4.3.6 --- In vitro RA synthesizing reaction --- p.68 / Chapter 4.3.7 --- Statistical analyses --- p.68 / Chapter 4.4 --- Results --- p.70 / Chapter 4.4.1 --- "Comparison of the relative expression level of Raldh 1, Raldh2 and Raldh3 between embryos of diabetic and non-diabetic mice injected with phlorizin or suspension vehicle as control" --- p.70 / Chapter 4.4.2 --- Comparison of the in vitro RA synthesizing activity of different isoforms of Raldh enzymes between embryos of diabetic and non-diabetic mice injected with phlorizin or suspension vehicle as control --- p.73 / Chapter 4.4.3 --- In situ expression pattern of Raldh2 in rat embryos cultured in medium containing varying concentrations of D-glucose --- p.77 / Chapter 4.4.4 --- Relative expression levels of Raldh2 in rat embryos cultured in medium supplemented with varying concentrations of D-glucose --- p.78 / Chapter 4.4.5 --- In vitro RA synthesizing activity ofRaldh2 in rat embryos cultured in medium supplemented with varying concentrations of D-glucose --- p.79 / Chapter 4.5 --- Discussion : --- p.82 / Chapter Chapter 5: --- In Vitro Supplementation with RA Rescued Rat Embryos from Hyperglycemia-induced Congenital Malformations / Chapter 5.1 --- Introduction --- p.86 / Chapter 5.2 --- Experimental Design --- p.88 / Chapter 5.3 --- Materials and Methods --- p.89 / Chapter 5.3.1 --- Preparation of RA --- p.89 / Chapter 5.3.2 --- Supplementation of RA to rat embryos in culture --- p.89 / Chapter 5.3.3 --- Morphological scoring system --- p.90 / Chapter 5.3.4 --- Statistical analyses --- p.90 / Chapter 5.4 --- Results --- p.92 / Chapter 5.4.1 --- Supplementation with RA rescued embryos from hyperglyce- miainduced malformations --- p.92 / Chapter 5.5 --- Discussion --- p.101 / Chapter Chapter 6: --- Conclusion and Future Perspectives / Chapter 6.1 --- Conclusion and Future Perspectives --- p.106 / References --- p.111

Introdução: A predição do prognóstico neonatal de fetos com hérnia diafragmática congênita (HDC) é um dos principais desafios na Medicina Fetal. A estimativa do volume pulmonar fetal pela ressonância nuclear magnética (RNM) correlaciona-se significativamente com o prognóstico neonatal. Recentemente, foi introduzida a técnica de rotação da imagem multiplanar (VOCALTM) de ultra-sonografia em três dimensões (US-3D), a qual tornou possível estimar o volume pulmonar fetal em casos com HDC. Objetivos: Estimar o volume pulmonar, pela US-3D através da técnica rotacional, em fetos com HDC isolada e comparar com a curva previamente descrita pelo mesmo autor; correlacionar o volume pulmonar fetal total com o prognóstico neonatal; avaliar a acurácia da técnica de rotação em medir o volume pulmonar fetal; e, avaliar outros marcadores ultra-sonográficos clássicos de prognóstico neonatal. Métodos: Este estudo prospectivo foi realizado no período de fevereiro de 2002 a Outubro de 2003 na Maternidade Necker-Enfants Malades, Université de Paris V-Paris, França, em 30 fetos com HDC entre 23 e 36 semanas de gestação. Cada gestante era submetida a um único exame de US-3D, sendo utilizada a técnica de rotação da imagem multiplanar (VOCALTM) para estimar o volume pulmonar fetal. Oito fetos nasceram pós interrupção terapêutica da gestação de acordo com as leis francesas. O volume pulmonar de cada feto (volume observado) foi comparado com a curva padão de nromalidade descrita previamente, sendo calculada a relação entre volumes observado/esperado, a qual foi comparada com a evolução neonatal. Além disso, foram avaliados outros fatores prognósticos clássicos, como: presença de fígado herniado, gravidade do desvio do mediastino, presença de polihidrâmnio, lado da lesão, relação ventrículo esquerdo/ventrículo direito e a relação área do pulmão contralateral/circunferência cefálica (SPC/CC). Foram comparadas também as variações intra- e inter-operador, e a acurácia da ultra-sonografia em estimar o volume pulmonar fetal após a autópsia dos 8 casos em que a gestação foi interrompida. Resultados: Redução importante do volume pulmonar foi observada em fetos com HDC quando esses valores foram distribuídos na curva padrão de normalidade previamente descrita. A relação entre volumes observado/esperado foi significativamente menor nos 12 casos que evoluíram a óbito (mediana= 0,30; variação= 0,12-0,66) em comparação com os 10 sobreviventes (mediana= 0,40; variação= 0,33-0,66; p= 0,017). Dentre outros fatores prognósticos, apenas a relação SPC/CC associou-se significativamente com os resultados neonatais. A predição de óbito neonatal e de sobrevida foi de 90% (9/10) e 75% (9/12) pelo volume pulmonar estimado pela US-3D e de 80% (8/10) e 66,7% (4/8) pela relação SPC/CC estimada pela US-2D, respectivamente. As variações intra- e inter-operadoras foram respectivamente de 0,78cm³ e 0,41cm³. Boa acurácia do método foi observada no presente estudo (84,86%). Conclusões: Em casos com HDC isolada, a estimativa do volume pulmonar fetal pela US-3D, utilizando a técnica rotacional, correlacionou-se significativamente com a evolução neonatal. A relação SPC/CC também se associou significativamente com os resultados neonatais / Introduction: Predicting neonatal outcome in fetuses with congenital diaphragmatic hernia (CDH) is one of the main challenges in Fetal Medicine. Fetal lung volume estimated by magnetic resonance imaging (MRI) associated significantely with neonatal outcome. Recently, the rotationa technique (VOCALTM) on threedimensional ultrasonography (3DUS) was introduced, which allows estimating fetal lung in fetuses with CDH. Objectives: To assess fetal lung volumes by 3DUS using the rotational technique (VOCALTM) in fetuses with isolated CDH, and to plot these values in the nomogram previously described by the same author; to correlate fetal lung volumes with neonatal outcome in cases with CDH; to evaluate the accuracy of 3DUS in estimating fetal lung volumes; and, to evaluate the classical prognostic factors in cases with CDH. Patients and Methods: From Febuary 2002 to October 2003, a prospective study was conducted in Maternité-Hôpital Necker Enfants Malades - Université de Paris V - France, in which 3D- ultrasonographic lung volumes were estiamted in 30 fetuses with isolated CDH 23 and 36 weeks of gestation. Each case was submitted to 3D-ultrasound examination once and 3Dvolumetric measurements were obstained by the technique of rotation of the multiplanar imaging (VOCALTM). Termination of pregnancy was perfromed in 8 cases according to the French law. Observed lung volume in each fetus with isolated CDH was compared to the expected fetal lung for specific gestational age determinated by the nomogram previously described. The observed/expected fetal lung volume was then calculated for each case and correlated with neonatal outcome. Besides,other classical sonographic prognostic were evaluated such as: hydramnios, herniated liver, herniated stomach, lung-over- head ratio, severe mediastinal shift and decreased left/right ventricles ratio. Intra- and inter-operator variabilities were also evaluated, as well as the accuracy of 3D- ultrasound in estimating fetal lung volumes. Results: Observed fetal lung volumes were extremely lower in fetuses with CDH when these values were ptotted in the nomogram of fetal lung volume against gestational age. The observed / expected fetal lung volume ratio was significantly downshifted in 12 cases with CDH who died (median: 0.30, range: 0.12-0.66) compared with 10 suvivors (median: 0.40, range: 0.33-0.66, p= 0,017). Among the other prognostic factors, only the LOHR associated significantly with neonatal outcome. Predicting neonatal deaths and neonatal survivals was 90% (9/10) and 75% (9/12) by fetal lung volume on 3DUS whilst it was 80% (8/10) and 66.7% (4/8) on 2DUS, respectivelly. Intra- and inter-variabilities were 0.78cm³ and 0.41cm³ in cases with CDH, respectively. Good accuracy of this method in estimating fetal lung volume was observed (84.86%). Conclusions: In cases with isolated CDH, fetal lung volume estimated by 3D-ultrasonography using the rotational technique corretated significantly with neonatal outcome. LOHR also associated significantly with neonatal outcome

Lam, Yuk Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 142-157). / Abstracts in English and Chinese. / ABSTRACT --- p.i / 摘要 --- p.iv / ACKNOWLEDGEMENTS --- p.vi / CONTRIBUTORS --- p.viii / PUBLICATIONS --- p.ix / LIST OF TABLES --- p.x / LIST OF FIGURES --- p.xi / LIST OF ABBREVIATIONS --- p.xiii / TABLE OF CONTENTS --- p.xiv / Chapter SECTION I: --- BACKGROUND --- p.1 / Chapter CHAPTER 1: --- PRENATAL DIAGNOSIS OF FETAL ANEUPLOIDIES --- p.2 / Chapter 1.1 --- The need for prenatal screening and diagnosis --- p.2 / Chapter 1.2 --- Patau Syndrome (Trisomy 13) --- p.2 / Chapter 1.3 --- Current methods for fetal aneuploidy detection --- p.4 / Chapter 1.3.1 --- Routine prenatal screening tests --- p.4 / Chapter 1.3.2 --- Definitive prenatal diagnosis by invasive procedures --- p.7 / Chapter 1.4 --- New approach for noninvasive prenatal diagnosis --- p.11 / Chapter 1.4.1 --- Circulating fetal cells --- p.11 / Chapter 1.4.2 --- Cell-free fetal nucleic acids in maternal circulation --- p.12 / Chapter 1.4.3 --- Diagnostic applications of cell-free fetal nucleic acids in maternal plasma --- p.12 / Chapter CHAPTER 2: --- DEVELOPMENT OF FETAL EPIGENETIC MARKERS IN MATERNAL PLASMA --- p.17 / Chapter 2.1 --- Limitations of fetal DNA markers --- p.17 / Chapter 2.2 --- DNA methylation is an actively-researched area under the field of epigenetics --- p.18 / Chapter 2.3 --- Genome-scale DNA methylation analysis brings new insight into epigenetics --- p.20 / Chapter 2.4 --- The first demonstration of using an epigenetic method for detecting maternally-inherited fetal DNA in maternal plasma --- p.22 / Chapter 2.5 --- The first universal marker for fetal DNA in maternal plasma --- p.24 / Chapter 2.6 --- Discovery of more fetal epigenetic markers --- p.25 / Chapter 2.6.1 --- Methylated fetal epigenetic markers are more desirable --- p.25 / Chapter 2.6.2 --- Discovery of hypermethylated fetal epigenetic markers by studying tumor suppressor genes --- p.26 / Chapter 2.6.3 --- Discovery of hypermethylated fetal epigenetic markers on chromosome 21 --- p.28 / Chapter 2.7 --- Noninvasive detection of fetal aneuploidies using fetal epigenetic markers --- p.29 / Chapter 2.7.1 --- Noninvasive detection of fetal trisomy 18 by the epigenetic allelic ratio (EAR) approach --- p.29 / Chapter 2.7.2 --- Noninvasive detection of fetal trisomy 21 by the epigenetic-genetic (EGG) approach --- p.30 / Chapter 2.8 --- Aim of thesis --- p.32 / Chapter SECTION II: --- MATERIALS AND METHODS --- p.34 / Chapter CHAPTER 3: --- METHODS FOR QUANTITATIVE ANALYSIS OF DNA METHYLATION --- p.35 / Chapter 3.1 --- Subject recruitment and sample collection --- p.35 / Chapter 3.2 --- Sample processing --- p.38 / Chapter 3.3 --- DNA extraction --- p.38 / Chapter 3.3.1 --- Placental tissues --- p.38 / Chapter 3.3.2 --- Maternal blood cells --- p.39 / Chapter 3.3.3 --- Maternal plasma --- p.40 / Chapter 3.4 --- Methylated DNA immunoprecipitation and tiling array analysis (MeDIP-chip) --- p.41 / Chapter 3.4.1 --- Principles --- p.41 / Chapter 3.4.2 --- DNA sample and array processing --- p.43 / Chapter 3.4.2.1 --- DNA preparation and target hybridization --- p.43 / Chapter 3.4.2.2 --- Data analysis --- p.44 / Chapter 3.5 --- DNA methylation analysis on randomly-chosen regions on chromosome / Chapter 3.6 --- Bisulfite conversion --- p.46 / Chapter 3.6.1 --- Principles of bisulfite conversion --- p.46 / Chapter 3.6.2 --- Procedures of bisulfite conversion --- p.46 / Chapter 3.7 --- Quantitative analysis of DNA methylation --- p.47 / Chapter 3.7.1 --- Bisulfite PCR and genomic sequencing --- p.47 / Chapter 3.7.1.1 --- Primer design for bisulfite polymerase chain reaction (PCR) --- p.47 / Chapter 3.7.1.2 --- Bisulfite PCR --- p.49 / Chapter 3.7.1.3 --- Cloning --- p.50 / Chapter 3.7.1.4 --- Bisulfite genomic sequencing --- p.52 / Chapter 3.7.1.5 --- Data acquisition and interpretation --- p.53 / Chapter 3.7.2 --- EpiTYPER，a mass-spectrometry-based method --- p.54 / Chapter 3.7.2.1 --- Principles of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) --- p.54 / Chapter 3.7.2.2 --- Primer design of the EpiTYPER assay --- p.55 / Chapter 3.7.2.3 --- The EpiTYPER assay and its principle --- p.56 / Chapter 3.8 --- Methylation-sensitive restriction enzyme (MSRE)-mediated real-time quantitative PCR (qPCR) --- p.61 / Chapter 3.9 --- Digital PCR --- p.66 / Chapter 3.9.1 --- Principles of digital PCR --- p.66 / Chapter 3.9.2 --- Poisson distribution --- p.68 / Chapter 3.10 --- Statistical analyses --- p.69 / Chapter SECTION III: --- SYSTEMATIC IDENTIFICATION OF A FETAL DNA METHYLATION MARKER ON CHROMOSOME 13 FOR DETECTION OF FETAL TRISOMY 13 --- p.70 / Chapter CHAPTER 4: --- SYSTEMATIC IDENTIFICATION OF POTENTIAL FETAL EPIGENETIC MARKERS BY MEDIP-CHIP ANALYSIS --- p.71 / Chapter 4.1 --- Systematic discovery of fetal epigenetic markers on chromosome 13 by MeDIP-chip analysis --- p.71 / Chapter 4.2 --- Experimental design --- p.73 / Chapter 4.3 --- Results --- p.76 / Chapter 4.3.1 --- Identification of differentially methylated DNA regions by MeDIP-chip or non-MeDIP-chip approaches followed by EpiTYPER analysis --- p.76 / Chapter 4.3.2 --- Confirmation of differential methylation patterns and exclusion of regions with high inter-individual variations by EpiTYPER analysis --- p.82 / Chapter 4.3.3 --- Confirmation of differential DNA methylation patterns with higher resolution by bisulfite sequencing --- p.85 / Chapter 4.4 --- Discussion --- p.95 / Chapter CHAPTER 5: --- THE APPLICATION OF FETAL EPIGENETIC MARKER ON CHROMSOME 13 FOR DETECTION OF FETAL TRISOMY 13 --- p.98 / Chapter 5.1 --- Identification of a fetal epigenetic marker on chromosome 13 for the detection of fetal trisomy 13 by the epigenetic-genetic (EGG) chromosome dosage approach --- p.98 / Chapter 5.2 --- Experimental design --- p.101 / Chapter 5.3 --- Results --- p.105 / Chapter 5.3.1 --- Optimization of the digestion protocol --- p.105 / Chapter 5.3.2 --- Detection of digestion-resistant EFNB2-3'UTR moleculesin maternal plasma --- p.109 / Chapter 5.3.3 --- Evaluation of the fetal specificity of digestion-resistant EFNB2´ؤ3 'UTR DNA molecules in maternal plasma --- p.111 / Chapter 5.3.4 --- Comparison of EFNB2-3'UTR methylation profiles between the euploid and trisomy 13 placental tissue samples --- p.115 / Chapter 5.3.5 --- Chromosome dosage analysis by the EGG analysis using placental tissue samples --- p.118 / Chapter 5.4 --- Discussion --- p.122 / Chapter SECTION IV: --- CONCLUDING REMARKS --- p.125 / Chapter CHAPTER 6: --- CONCLUSION AND FUTURE PERSPECTIVES --- p.126 / Chapter 6.1 --- Development of fetal epigenetic markers for noninvasive prenatal diagnosis --- p.126 / Chapter 6.2 --- Systematic identification of fetal epigenetic markers on chromosome13 --- p.127 / Chapter 6.3 --- Detection of fetal trisomy 13 by the epigenetic-genetic (EGG) relative chromosome dosage analysis --- p.129 / Chapter 6.4 --- Future perspectives --- p.132 / Appendix I --- p.134 / Appendix II --- p.136 / REFERENCES --- p.142

In dieser Arbeit werden die intratrachealen Doppler-Fluáparameter w?hrend der FAB bei 47 gesunden menschliche Feten im zweiten und dritten Trimenon analysiert. Die Dauer der Inspiration, die Dauer der Exspiration sowie die Atemfrequenz unterlagen zwischen den einzelnen Gruppen nur geringen Ver?nderungen. Wir konnten zwischen der 24. und der 35. SSW einen signifikanten Anstieg des medianen intratrachealen Fluávolumens w?hrend der regelm?áigen FAB mit zunehmendem Gestationsalter nachweisen. Das fetale Atemzugvolumen fiel dagegen nach der 36. SSW ab. Die Differenz zwischen dem inspiratorischen Fluávolumen und dem exspiratorischen zeigte einen interessanten Verlauf mit einer positiven Bilanz in den ersten vier Gruppen (20.-35. SSW) und eine negative Bilanz in der letzten Gruppe (36.-40. SSW). Dies k?nnte bedeuten, daá nach der 36. SSW w?hrend der ausgew?hlten Atemepisoden tendenziell mehr Fl?ssigkeit aus- als eingeatmet wurde. Unsere Untersuchungen zeigen, daá in den letzten Wochen vor der Geburt eine wichtige Umstellung der fetalen Ventilation stattfindet, die einen Abfall der Lungenfl?ssigkeit bewirkt. Ferner konnten wir zeigen, daá die Trachea beim Schafsfeten sonographisch darstellbar ist. Es konnte ferner gezeigt werden, daá die mittels hochaufl?sender Sonographie durchgef?hrten Trachealmessungen mit den pathologischen Messungen ?bereinstimmten. / Assessment of tracheal fluid flow was obtained in 47 healthy human fetuses (GA 20-40 weeks) in which FBM were seen by B-Mode scan. Color Doppler was applied to visualise the tracheal fluid flow, followed by spectral Doppler to record the velocity waveforms. The breathing rate, the inspiration and expiration time and the volume obtained by integration of the tracheal fluid flow displaced during fetal breathing were calculated. The fetal breathing rate was not different between the groups. Both the time of inspiration and expiration showed a significant increase at 24 weeks followed by a constant course until Term. The volume of tracheal fluid flow moved during inspiration (Vi) and expiration (Ve) increased until 35 weeks followed by a flattening until term suggesting either a reduction of lung liquid production or a diminished lung liquid volume. The median difference between Vi and Ve was positive in the first four age groups and negative in the last one, suggesting that mature fetuses have the tendency to expire more than to inspire. We furthermore showed that in the ovine fetus at mid-gestation shows that optimal views of the fetal trachea allowing accurate measurements can be obtained in almost all the cases.

Thesis (doctoral)--Universiteit Leiden, 2005. / Title from e-book title screen (viewed Aug. 10, 2009). Description based on print version record. Includes bibliographical references and index.

Another attempt was made to identify CpG-rich paralogues on chromosome 21 for dosage analysis. Methylation profiles of 14 paralogous CpG-rich clusters were screened by bisulfite genomic sequencing and/or combined bisulfite restriction analysis. One of the paralogue pairs showed similar differential methylation patterns, and three other CpG-rich clusters located on chromosome 21 were hypomethylated in the placentas and completely methylated in the maternal blood cells. Detection methods for these novel epigenetic markers were described and discussed, and potential applications were also suggested. / In the second part of this thesis, a technique called digital PCR was used for detecting and quantifying cell-free fetal DNA in maternal plasma. DNA templates are first diluted to a single molecule level and partitioned to separate compartments before subjecting to polymerase chain reaction amplification. Quantification is then made by counting the number of positive reactions directly. Such a technique has allowed the reliable detection of fetal DNA from a high background of maternal plasma DNA, and allows absolute quantification of fetal DNA without using a calibration curve. As a proof-of-principle project, a non-polymorphism-based approach called digital relative chromosome dosage (RCD) method was developed to detect chromosomal imbalance in trisomic cases. The implementation of digital PCR was further facilitated with the technology of integrated fluidics circuits (IFCs), by which nanolitre volumes of reaction mixtures could be manipulated in a high-throughput manner. Such a microfluidics digital PCR system was evaluated systematically and shown to be highly accurate, precise and sensitive compared to other existing detection platforms. The technology has been applied with the RCD approach for rapid detection of trisomy 21 from amniotic fluid samples and 100% accuracy was attained. With the development of new universal markers and robust detection platforms, it is envisioned that circulating fetal DNA in maternal plasma can be applied to an expanding range of clinical applications in the near future. / The first part of my thesis focused on the discovery of new epigenetic markers for fetal DNA detection. Methylation profiles of 7 selected CpG islands on chromosome 21 were revealed by bisulfite sequencing, in the hope of identifying regions with differential methylation patterns between placentas and maternal blood cells. Out of the 14 sub-regions of these CpG islands, five displayed significant difference between the two tissue type and were promising marker candidates. / The presence of circulating fetal DNA in maternal plasma provides a non-invasive source of fetal genetic materials for prenatal diagnosis. Reliance on Y-chromosomal sequences for detecting fetal-specific signals from the background of maternal plasma DNA, however, has restricted the applications to 50% of pregnancies. For a wider extent of diagnostic applications, sex- and polymorphism-independent fetal markers would be necessary. Recently, an epigenetic approach has been adopted to discriminate between the fetal and maternal DNA circulating in maternal plasma. Based on the differential DNA methylation status between the fetus and mother, universal fetal DNA markers have been developed and applied to detect fetal signals in maternal plasma. Identification of more of such markers is important for the development of the field. / Lun, Miu Fan. / Adviser: Yuk Ming Dennis Lo. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3292. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 233-256). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.