Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Introdução: A craniossinostose é causada pela fusão prematura de uma ou mais suturas cranianas, levando à deformidade do crânio. Formas sindrômicas ocorrem quando a craniossinostose é associada a características dismorfológicas adicionais. A fusão precoce das suturas pode ser causada por fatores ambientais e genéticos. No presente trabalho, pretende-se reconhecer os diagnósticos clínicos e características fenotípicas da craniossinostose em pacientes atendidos nos ambulatórios de Genética Médica do Hospital de Clinicas de Porto Alegre no período de 2006 a 2016. O protocolo de investigação incluiu anamnese, exame dismorfológico e revisão de prontuário, incluindo exames de investigação realizados. Resultados: Entre 2006 e 2016, foram avaliados 133 indivíduos com craniossinostose, sendo que 121 reuniram critérios para inclusão neste estudo. A idade média de diagnóstico da craniossinostose foi de 38,4 meses. A sutura mais frequentemente acometida foi a sutura metópica. Houve maior proporção de casos sindrômicos (69,4%). Em 25 desses pacientes, foram identificadas as síndromes de Apert, Crouzon, Pfeiffer, Muenke, Craniofrontonasal ou Saethre-Chotzen. Síndromes não tipicamente relacionadas a craniossinostose foram também identificadas, como distrofia miotônica tipo 1 (n=2), síndrome de Gorlin, síndrome de Beckwith-Wiedemann e galactosemia. Os sinais clínicos não eram típicos de qualquer síndrome particular em 32 indivíduos (38,1% dos casos sindrômicos). Características fenotípicas frequentes incluíram malformações de extremidades (35,5%), do sistema nervoso central (32,1%), cardiovasculares (21,4%) e genito-urinárias (16,6%). Foram observadas malformações raras como espinha bífida (n=3), hérnia diafragmática congênita (n=3) e hipoplasia congênita de parede abdominal (n=2). Anormalidades citogenéticas ou moleculares foram identificadas em 18 indivíduos sindrômicos, sendo a síndrome de Muenke o diagnóstico mais frequente (n=7). Discussão: A maior proporção de casos sindrômicos em relação a outras séries é possivelmente relacionada ao fato de tratar-se de casos atendidos em um serviço de Genética clínica. Observou-se diagnóstico significativamente tardio na presente casuística, reforçando a necessidade de estratégias de saúde pública envolvendo treinamento de recursos humanos e otimização da referência aos centros terciários. O acometimento multissistêmico reforça a importância do acompanhamento multidisciplinar. Conclusão: O estudo demonstra uma amostra amplamente heterogênea em termos clínicos, genéticos e terapêuticos. É fundamental o desenvolvimento de estratégias de educação contínua não apenas dentro da equipe, mas também ao acessar pacientes e familiares, através do aconselhamento genético e de ferramentas de comunicação. Para isso, propõe-se uma cartilha informativa sobre craniossinostoses para pacientes e familiares. Faltam estudos em países em desenvolvimento para análise comparativa dos dados em contextos sociais semelhantes. / Introduction: Craniosynostosis is caused by premature fusion of one or more cranial sutures, leading to deformity of the skull. Syndromic forms occur when craniosynostosis is associated with additional dysmorphological features. Early suture fusion can be caused by environmental and genetic factors. In this study, it is intended to recognize the clinical diagnosis and phenotypic characteristics of craniosynostosis in patients attending Medical Genetics outpatient clinics of Hospital de Clínicas de Porto Alegre from 2006 to 2016. The research protocol included anamnesis, dysmorphological examination, review of medical records and investigations carried out. Results: Between 2006 and 2016, 133 individuals with craniosynostosis were evaluated, and 121 met inclusion criteria for this study. The mean age at diagnosis of craniosynostosis was 38.4 months. Metopic suture was the most commonly involved. There was a higher proportion of syndromic cases (69.4%). In 25 of these patients, Apert, Crouzon, Pfeiffer, Muenke, Craniofrontonasal or Saethre-Chotzen syndromes were identified. Syndromes not typically associated to craniosynostosis were also identified, such as myotonic dystrophy type 1 (n = 2), Gorlin syndrome, Beckwith-Wiedemann syndrome and galactosemia. Clinical signs were not typical of any particular syndrome in 32 individuals (38.1% of syndromic cases). Frequent phenotypic features included extremities (35.5%), central nervous system (32.1%), cardiovascular (21.4%) and genitourinary malformations (16.6%). Rare malformations such as spina bifida (n = 3), diaphragmatic hernia (n = 3) and congenital abdominal wall hypoplasia (n = 2) were observed. Cytogenetic or molecular abnormalities were identified in 18 syndromic patients, and Muenke syndrome was the most frequent diagnosis (n = 7). Discussion: The higher proportion of syndromic cases than in other series is possibly due to the fact that these cases are treated in a clinical genetics service. Significantly late diagnosis was observed in the present series, reinforcing the need for public health strategies involving training of human resources, optimization of referral to tertiary centers and active search strategies. Multisystemic involvement reinforces the importance of multidisciplinary follow-up. Conclusion: This study demonstrates a widely heterogeneous clinical, genetic and therapeutic sample. Strategies for continuous education within the team, patients and family members, through genetic counseling and communication tools are important, so it is proposed an information booklet for patients and families. There is a scarcity of case series from developing countries for comparative analysis in similar social contexts.

Hypofractionated conformal stereotactic radiotherapy (HCSRT) has been used for the treatment of AVMs at the Umeå University Hospital since 1986. From this year and onwards an increasing number of patients with single or oligo brain metastases have also been treated using this technique. In paper I we have retrospectively evaluated our treatment results of AVMs in terms of obliteration and complications. The rates of obliteration and complications seem to be comparable with SRS even if the AVM volumes in our series were larger than in most series with SRS. In paper II we have retrospectively evaluated the results in terms of local control, survival and complications in two groups of patients with single or oligo brain metastases. One group was treated with HCSRT alone and the other group was treated with whole brain radiotherapy in combination with a stereotactic boost. Controversy still exists concerning the benefit of additional use of WBRT in combination with stereotactic irradiation. The survival times were equal in the two groups and no significant difference in local control was observed. The omission of WBRT seems to carry a higher risk for development new brain metastases distant from the irradiated area. In paper III we report the treatment results in a subgroup of AVMs treated with a combination of embolisation and HCSRT. We also focus on the reduction of vascular density within the nidus of an AVM and propose a method to digitally compare images and more objectively assess a reduction in vascular density following embolisation. Obliteration rates seem comparable with other series using a combination of SRS and embolisation even if our rate of complications was higher than what is usually reported. Using luminescence as measure of vascular density all AVMs seemed to be less dense after embolisation. Treatment accuracy in terms of reproducibility of the isocenter in consecutive treatment sessions is crucial in fractionated radiotherapy. In paper IV we have radiologically evaluated the reproducibility of the isocenter in successive treatment sessions using the non invasive relocatable Fixster frame. There was a high degree of reproducibility and only small errors that most likely is of no clinical importance. A reliable dose plan is equally important as a tool to predict the dose delivered inside and outside the target volume. In paper V we have evaluated the reliability of treatment plans in HCSRT for targets of different geometry and size. A liquid ion chamber and gel dosimeter was used for assessment of dose distribution and absorbed dose. The doseplanning system proved to be accurate in predicting the absorbed dose and dose distribution for the different targets.

Caffeine, a mild central nervous system stimulant, is a natural component of common hot and cold beverages like coffee, tea, sodas and cocoa. Animal studies have demonstrated caffeine’s teratogenic effects when administered at high concentrations; however, epidemiologic studies have yielded inconsistent results in humans. Because caffeine containing beverages are commonly consumed by pregnant women, we examined the prevalence of use and explored possible associations of maternal caffeine consumption with cardiovascular malformations in 3,274 cases matched with 3,519 controls enrolled in the 1981-89 “Baltimore-Washington Infant Study,” a population-based case-control investigation. We explored several key aspects of the quality of and distribution of measurements of caffeine consumption among mothers in the study population. We concluded with recommendations for refining data collection to reduce potential bias associated with assessing both caffeine content and changes in caffeine consumption during pregnancy in order to inform future research studies and birth defects/adverse birth outcomes surveillance programs.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 4 uppsatser.

Orientadores: Iscia Teresinha Lopes Cendes, Fábio Rossi Torres / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-23T06:33:25Z (GMT). No. of bitstreams: 1 Souza_DanielaAguiar_D.pdf: 4993968 bytes, checksum: b0d9bcf5acf25db217c9dedcd7aa4bbc (MD5) Previous issue date: 2013 / Resumo: As malformações do desenvolvimento cortical (MDC) são distúrbios resultantes de defeitos na embriogênese do córtex cerebral e estão entre as principais causas conhecidas de atraso do desenvolvimento e epilepsia. Dentre os principais tipos de MDC podemos citar a heterotopia nodular periventricular (HNP), o espectro lissencefalia/heterotopia subcortical em banda (LIS/HSB) e a esquizencefalia. Alterações moleculares em genes que atuam em mecanismos que vão desde o controle da divisão celular até a migração neuronal foram identificadas como responsáveis pela etiologia de vários tipos de MDC. Tais descobertas, além de auxiliar na compreensão dos mecanismos envolvidos no desenvolvimento do córtex cerebral e doenças relacionadas, fornecem informações importantes para um melhor diagnóstico e tratamento dos pacientes. Neste contexto, o principal objetivo deste trabalho foi analisar do ponto de vista molecular um grande grupo de pacientes com MDC. A casuística foi composta por um grupo de 107 pacientes: 27 possuem HNP, 33 são afetados por LIS/HSB e 47 possuem esquizencefalia. Em um primeiro momento, foi realizada triagem de mutações de ponto em genes candidatos (FLNA, DCX, LIS1, EMX2, TUBA1A, TUBB2B e TUBA8) por sequenciamento (Sanger). Posteriormente, a técnica de MLPA (Multiplex Ligation-dependent Probe Amplification) foi utilizada para detectar variações estruturais em regiões candidatas, incluindo os genes FLNA, DCX e LIS1. Finalmente, a técnica de SNP-Array foi utilizada para análise das variações no número de cópias alélicas em regiões genômicas de alguns pacientes (copy number variation - CNV). Todas as mutações de ponto encontradas nas sequencias de DNA foram verificadas em um grupo de 200 indivíduos controles. Através do sequenciamento, foram identificadas três alterações patogênicas localizadas nos genes FLNA e DCX, através do MLPA foram encontradas seis alterações estruturais patogênicas nos genes FLNA, DCX e LIS1. Os ensaios de SNP-Array permitiram a identificação de vários CNVs com potencial deletério, incluindo 12 pacientes com 17 novas CNVs ainda não descritas na literatura. Tais CNVs envolvem vários potenciais genes candidatos para as MDC, incluindo os genes TSNARE, DAAM1, ARX, PLXNA1 e HAUS7. Concluindo, nossos resultados mostram uma baixa frequência de mutações em genes candidatos previamente relacionados às MDC, somente 2.8% (n=3/107) dos pacientes possuem variantes deletérias nas sequencias dos genes analisados e 18% (n=6/33 testados) dos pacientes analisados possuem alterações estruturais em regiões candidatas. Porém, através da abordagem genômica para identificação de variações estruturais, foram identificadas vá-rias regiões/genes candidatos potencialmente envolvidos com a etiologia das MDC (12/40= 30%). Nossos dados mostram que as MDC apresentam grande heterogeneidade genética, porém uma proporção significativa dos pacientes possuem variações estruturais que podem ser identificadas pela técnica de SNP-Array / Abstract: Malformations of cortical development (MCD) are disorders resulting from defects in the embryogenesis of the cerebral cortex and are one of the most important causes of developmental delay and epilepsy. The main types of MCDs are periventricular nodular heterotopia (PNH), lissencephaly/subcortical band heterotopia spectrum (LIS/SBH) and schizen-cephaly. Mutations in genes acting in mechanisms ranging from control of cell division to neuronal migration were identified as responsible for several types of MCDs. These advances not only improved our understanding about the mechanisms involved in the development of the cerebral cortex but have also provided relevant information that can be used for better diagnosis and management of patients. In this scenario, the main objective of this study was to access and perform a comprehensive molecular genetics study in a large cohort of patients with MCD. We have studied a total of 107 patients with MCDs divided in the following groups: 27 with PNH, 33 with LIS/SBH and 47 with schizencephaly. We first searched for sequence variations in candidate genes (FNLA, DCX, LIS1, EMX2, TU-BA1A, TUBB2B and TUBA8) using the Sanger sequencing method. Subsequently, we checked for structural variants in FLNA, DCX and LIS1 using Multiplex Ligation-dependent Probe Amplification (MLPA) technique. Finally, we took a genomic approach by using single nucleotide polymorphism (SNP)-array technology to studied copy number variations (CNV) in some patients. All sequence variants found were subsequently verified in a group of 200 control individuals. Our results showed 3 pathogenic sequence variants in FNLA and DCX, as well as 6 pathogenic structural variants detected by MLPA in FLNA, LIS1 and DCX. SNP-array technique detected 17 genomic regions, in 12 patients, containing new CNVs. These CNVs involve a number of potential new candidate genes for MCDs, including: TSNARE, DAAM1, ARX, PLXNA1 and HAUS7. In conclusion, our results show a low frequency of mutations in candidate genes previously associated with MCDs, only 2.8% (n=3/107) of our patients have deleterious sequence variants and 18% (n=6/33) have abnormal structural variants in candidate regions. However, by using a genomic approach to look for CNVs we were able to identify several candidate regions/genes that have the potential to be involved in MCDs (12/40= 30%). Our data show that MCDs are genetic heterogeneous; however, it seems that a significant proportion of patients have structural abnormalities that can be identified by SNP-array technology / Doutorado / Fisiopatologia Médica / Doutora em Ciências

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Les Polluants Organiques Persistants (POPs) sont des contaminants environnementaux composés des produits chimiques, mobiles, persistants, bioaccumulables, et toxiques. Les avancées dans la recherche au cours de ces dernières décennies ont montré que ces polluants présentent un grand risque de potentiel de toxicité, notamment chez les ours polaires où ils sont responsables d’une faible densité osseuse minérale du bacculum, chez les poissons des malformations de la colonne vertébrale, et un amincissement de la coquille d’oeuf chez les oiseaux. Le rapport entre les os et la coquille de l’oeuf est qu’ils ont le calcium comme composé principal, et sa concentration dans l’organisme est régulée par deux hormones endocriniennes telles que la parathormone et la calcitonine pouvant subir des perturbations endocriniennes. La densité minérale (calcium) de l’os ou la quantité du calcium dans l’oeuf détermine leurs résistances. En vue de comprendre, l’impact des POPs sur développement foetal du système squelettique chez les mammifères, cette étude a été conduite en émettant l’hypothèse qu’une exposition in utero à une mixture de POPs mimant les contaminants retrouvés dans la chaîne alimentaire en Arctique, induirait des malformations osseuses chez les foetus de rat, lesquelles seraient transmises aux générations suivantes via les pères. Une supplémentation en acide folique (AF) a également été investiguée pour contrecarrer les effets potentiels des POPs, car l’AF était supplémentée chez les femmes enceinte pour remédier à la malformation du tube neural. À cet effet, quatre groupes de rates Sprague-Dawley (F0) ont été gavées avec un mélange de POPs ou d’huile de maïs (contrôle). Elles ont été soumises à un régime alimentaire contenant soit une dose physiologique d’AF ou une dose supplémentée en AF. Les femelles ont été accouplées à des mâles non traités pour créer la génération F1. Les mâles F1 ont à leur tour été accouplés avec des femelles non traitées pour produire la génération F2 et ainsi de suite jusqu’à la génération F4. À chaque génération, les femelles ont été sacrifiées à 19,5 jours de gestation. Les foetus ont été prélevés et leurs squelettes ont été colorés pour observer le degré d’ossification et la longueur des os longs. Les résultats ont montré que dans les générations F1 et F2, ces POPs ont provoqué des retards d’ossification et une diminution de la longueur des os longs (p ≤ 0,05). Cet effet était absent dans la génération F3, mais la longueur des os était augmentée en F4 dans les lignées exposées à des POPs (p ≤ 0,05). Cependant, la supplémentation en AF utilisée n’a pas pallié les effets suivant une exposition à des POPs. Toutefois, l’impact de l’AF pour contrecarrer l’effet potentiel de ces polluants chez le foetus devrait être investigué davantage puisqu’elle n’a pas porté ses fruits chez le modèle de rat. En conclusion, une exposition des mâles in utero aux POPs a impacté l’ossification de la F1 jusqu’à la F4. / Persistent Organic Pollutants (POPs) are environmental contaminants composed of chemicals that are mobile, persistent, bioaccumulative, and toxic. Advances in research in recent decades have shown that these pollutants present a high risk of toxic potential, particularly in polar bears where they are responsible for low bacculum mineral bone density, in fish for spinal deformities, and eggshell thinning in birds. The relationship between bones and eggshells is that they have calcium as the main compound, and its concentration in the body is regulated by two endocrine hormones such as parathormone and calcitonin which can undergo endocrine disruption. The mineral density (calcium) of the bone or the amount of calcium in the egg determines their resistance. In order to understand the impact of POPs on fetal development of the skeletal system in mammals,this study was conducted under the hypothesis that in utero exposure to a mixture of POPs mimicking contaminants found in the Arctic food chain would induce bone malformations in rat fetuses, which would be transmitted to subsequent generations via the fathers. Folic acid (FA) supplementation has also been investigated to counteract the potential effects of POPs, as FA was supplemented in pregnant women to correct neural tube defects. For this purpose, four groups of Sprague-Dawley (F0) rats were gavaged with a mixture of POPs or corn oil (control). They were fed a diet containing either a physiological dose of AF or a dose supplemented with AF. Females were mated to untreated males to create the F1 generation. The F1 males were in turn mated with untreated females to produce the F2 generation and so on until the F4 generation. In each generation, females were sacrificed at 19.5 days gestation. Fetuses were collected and their skeletons were stained to observe the degree of ossification and the length of long bones. Results showed that in the F1 and F2 generations, these POPs caused delayed ossification and a decrease in long bone length (p ≤ 0.05). This effect was absent in generation F3, but bone length was increased in F4 in lines exposed to POPs (p ≤ 0.05). However, the AF supplementation used did not alleviate the effects following exposure to POPs. However, the impact of FA to counteract the potential effect of these pollutants in the fetus should be further investigated since it was not successful in the rat model. In conclusion, exposure of males in utero to POPs impacted ossification from F1 to F4.