996 resultados para pre-column derivatization
Resumo:
Pregnancy is characterized by a state of heightened coagulation, which is exacerbated in pathological conditions such as pre-eclampsia (PET). PET is further associated with abnormal maternal inflammation and increased circulating microparticles (MP); however, a mechanistic link between these pathological features has never been established. It is proposed in this thesis that abnormal maternal inflammation is causally linked to pro-coagulant trophoblast MP shedding via a mechanism mediated by the pro-inflammatory cytokine tumour necrosis factor alpha (TNF), thereby contributing to maternal coagulopathies associated with PET. Using thromboelastography (TEG) and standard laboratory tests, haemostatic function was evaluated in PET and normotensive subjects at delivery and post-partum. Furthermore, the effects of the menstrual cycle and oral contraceptive (OC) use on haemostatic function were assessed in non-pregnant subjects in order to understand their influence on post-partum haemostasis. Plasma TNF and pro-coagulant MP levels were evaluated in the pregnant subjects. Using chorionic villi explants from human term placentas, MPs were quantified after TNF administration. The pro-coagulant potential of placental MPs was evaluated by TEG by spiking whole-blood with medium containing MPs from chorionic villi. TEG identified increased whole-blood coagulability in PET subjects at delivery, demonstrating its increased sensitivity over standard laboratory tests at identifying haemostatic alterations associated with PET. Haemostatic alterations were normalized by six weeks post-partum. TEG also identified cyclic haemostatic variations associated with OC use. Chorionic villi treated with TNF (1 ng/ml) shed significantly more MPs than untreated placentas. MPs from chorionic villi increased the coagulability of whole-blood. Together, results provide evidence supporting the concept that abnormal maternal inflammation is causally linked to the development of maternal coagulopathies in pregnancy complications. Moreover, TEG may be superior to standard laboratory tests in evaluating haemostasis in pregnant and non-pregnant subjects.
Resumo:
Pre-eclampsia (PE) is a hypertensive disorder of pregnancy characterized by maternal systemic endothelial dysfunction. While the clinical manifestations resolve soon after delivery, a large body of epidemiological evidence indicates significant long-term maternal risk for cardiovascular disease (CVD) after PE. The mechanisms by which PE and future CVD are associated are unclear, although shared constitutional risk factors likely contribute to the features of endothelial dysfunction characteristic to both. We postulate that PE offers a window of opportunity for the identification of unique markers of dysfunction in the earliest stages of disease that may be used to validate cardiovascular risk screening in the early postpartum period. The studies presented in this thesis provide evidence of changes in circulating factors in women with a recent history of PE. Using blood samples collected within the first year of pregnancy, unique patterns of microRNA expression, enrichment of coagulation system proteins and endothelial progenitor cell dysfunction were described. Many of the described changes appear to be independent of cardiovascular risk. In addition to alterations in circulating factors however, longitudinal postpartum assessments demonstrated that microvascular and cardiac abnormalities were evident in the early periods postpartum after a pre-eclamptic pregnancy. Collectively, the data presented in this thesis reveal that physiological alterations in women with a recent history of PE are not necessarily dependent on clinical parameters of cardiovascular risk, and that resulting dysfunction may be demonstrated within the first year postpartum. Importantly, the biomarkers presented herein are all demonstrated elsewhere in the literature to benefit from lifestyle modification and risk reduction. In closing, the findings of this thesis support a need for cardiovascular risk screening based on obstetrical history, namely after pregnancies complicated by PE.
Resumo:
This article presents an educational experiment carried out in the Primary School Teaching Degree at the University of Barcelona. Specifically, the article analyses the application of the “Work Corners” approach in a core subject. In a three-year action research process, trainers put into practice an innovation which enabled them to boost cooperative work and reflexive learning among trainees. Firstly, the theoretical model underpinning the project and guiding many of the actions carried out by the training team is presented. After providing detailed information on the practical development of the experiment, the data-gathering process and its results are shown. Various information-gathering strategies were used in assessing the project, such as a questionnaire, participant observation, and teachers’ diaries. The results demonstrate, amongst other things, that “work corners” offer viable and appropriate educational conditions for the articulation of theoretical and practical knowledge, for building professional knowledge, and therefore, the beginnings of a reflexive teaching practice.
Resumo:
The recombinant production of a respiratory syncytial virus (RSV) candidate vaccine BBG2Na in baby hamster kidney cells (BHK-21 cells) was investigated. BBG2Na consists of a serum-albumin-binding region (BB) fused to a 101-amino-acid fragment of the RSV G-protein. Semliki Forest virus-based expression vectors encoding both intracellular and secreted forms of BBG2Na were constructed and found to be functional. Affinity recovery of BBG2Na employing human serum albumin columns was found to be inefficient due to the abundance of BSA in the applied samples. Instead, a strategy using a tailor-made affinity ligand based on a combinatorially engineered Staphylococcus aureus protein A domain, showing specific binding to the G-protein part of the product, was evaluated. In conclusion, a strategy for production and successful recovery of BBG2Na in mammalian cells was created, through the development of a product-specific affinity column.
Resumo:
An example of a sigma -compact infinite-dimensional pre-Hilbert space H is constructed such that any continuous linear operator T: H --> H is of the form T = lambdaI + F for some lambda is an element of R and for a finite-dimensional continuous linear operator F. A class of simple examples of pre-Hilbert spaces nonisomorphic to their closed hyperplanes is given. A sigma -compact pre-Hilbert space H isomorphic to H x R x R and nonisomorphic to H x R is also constructed.