2 resultados para Recém-nascidos Teses
em Repositório Institucional da Universidade de Aveiro - Portugal
Resumo:
Chapter 1 introduces the scope of the work by identifying the clinically relevant prenatal disorders and presently available diagnostic methods. The methodology followed in this work is presented, along with a brief account of the principles of the analytical and statistical tools employed. A thorough description of the state of the art of metabolomics in prenatal research concludes the chapter, highlighting the merit of this novel strategy to identify robust disease biomarkers. The scarce use of maternal and newborn urine in previous reports enlightens the relevance of this work. Chapter 2 presents a description of all the experimental details involved in the work performed, comprising sampling, sample collection and preparation issues, data acquisition protocols and data analysis procedures. The proton Nuclear Magnetic Resonance (NMR) characterization of maternal urine composition in healthy pregnancies is presented in Chapter 3. The urinary metabolic profile characteristic of each pregnancy trimester was defined and a 21-metabolite signature found descriptive of the metabolic adaptations occurring throughout pregnancy. 8 metabolites were found, for the first time to our knowledge, to vary in connection to pregnancy, while known metabolic effects were confirmed. This chapter includes a study of the effects of non-fasting (used in this work) as a possible confounder. Chapter 4 describes the metabolomic study of 2nd trimester maternal urine for the diagnosis of fetal disorders and prediction of later-developing complications. This was achieved by applying a novel variable selection method developed in the context of this work. It was found that fetal malformations (FM) (and, specifically those of the central nervous system, CNS) and chromosomal disorders (CD) (and, specifically, trisomy 21, T21) are accompanied by changes in energy, amino acids, lipids and nucleotides metabolic pathways, with CD causing a further deregulation in sugars metabolism, urea cycle and/or creatinine biosynthesis. Multivariate analysis models validation revealed classification rates (CR) of 84% for FM (87%, CNS) and 85% for CD (94%, T21). For later-diagnosed preterm delivery (PTD), preeclampsia (PE) and intrauterine growth restriction (IUGR), it is found that urinary NMR profiles have early predictive value, with CRs ranging from 84% for PTD (11-20 gestational weeks, g.w., prior to diagnosis), 94% for PE (18-24 g.w. pre-diagnosis) and 94% for IUGR (2-22 g.w. pre-diagnosis). This chapter includes results obtained for an ultraperformance liquid chromatography-mass spectrometry (UPLC-MS) study of pre-PTD samples and correlation with NMR data. One possible marker was detected, although its identification was not possible. Chapter 5 relates to the NMR metabolomic study of gestational diabetes mellitus (GDM), establishing a potentially predictive urinary metabolic profile for GDM, 2-21 g.w. prior to diagnosis (CR 83%). Furthermore, the NMR spectrum was shown to carry information on individual phenotypes, able to predict future insulin treatment requirement (CR 94%). Chapter 6 describes results that demonstrate the impact of delivery mode (CR 88%) and gender (CR 76%) on newborn urinary profile. It was also found that newborn prematurity, respiratory depression, large for gestational age growth and malformations induce relevant metabolic perturbations (CR 82-92%), as well as maternal conditions, namely GDM (CR 82%) and maternal psychiatric disorders (CR 91%). Finally, the main conclusions of this thesis are presented in Chapter 7, highlighting the value of maternal or newborn urine metabolomics for pregnancy monitoring and disease prediction, towards the development of new early and non-invasive diagnostic methods.
Resumo:
As farinhas infantis, alimentos que se destinam a recém-nascidos e crianas at idade pr-escolar, devem satisfazer todas as necessidades nutricionais que se verificam durante o perodo de crescimento e desenvolvimentos fsico e mental desta faixa etria. Desta forma, so frequentemente adicionadas prmisturas de vitaminas e minerais durante a sua produo (fortificao), de maneira a que a quantidade adicionada e a composio do produto final sejam concordantes com a legislao comunitria em vigor. A implementao, na linha de produo, de mtodos alternativos de anlise amigos do ambiente e passveis de obter resultados rpidos acerca da composio nutricional dos produtos alimentares, mesmo antes destes serem embalados, permite redues de tempo, custos e um melhor controlo do processo de produo. A espectroscopia FT-NIR e a espectroscopia de XRF so tcnicas que permitem a quantificao de micronutrientes e possuem caractersticas fundamentais ao controlo rpido de processos. Neste trabalho foram desenvolvidos modelos de calibrao para quantificao de zinco, por espectroscopia de XRF, em trs receitas de pr-misturas de vitaminas e minerais. Construram-se dois modelos de calibrao, um com um R2 de 0,990 e um SEC de 26,624 mg/100g e outro com um R2 de 0,927 e um SEC de 18,838 mg/100g. Estes resultados indicam que os modelos de calibrao construdos so adequados e podem ser usados na determinao rpida do teor de zinco em pr-misturas de vitaminas e minerais. Foram tambm verificadas as rectas de calibrao existentes para quantificao de clcio e ferro por espectroscopia de XRF e quantificao de vitamina C por espectroscopia FT-NIR para aplicao nas novas receitas de pr-misturas de vitaminas e minerais.