951 resultados para Vagal Tone
Resumo:
The purpose of the present thesis was to explore different aspects of decision making and expertise in investigations of child sexual abuse (CSA) and subsequently shed some light on the reasons for shortcomings in the investigation processes. Clinicians’ subjective attitudes as well as scientifically based knowledge concerning CSA, CSA investigation and interviewing were explored. Furthermore the clinicians’ own view on their expertise and what enhances this expertise was investigated. Also, the effects of scientific knowledge, experience and attitudes on the decision making in a case of CSA were explored. Finally, the effects of different kinds of feedback as well as experience on the ability to evaluate CSA in the light of children’s behavior and base rates were investigated. Both explorative and experimental methods were used. The purpose of Study I was to investigate whether clinicians investigating child sexual abuse (CSA) rely more on scientific knowledge or on clinical experience when evaluating their own expertise. Another goal was to check what kind of beliefs the clinicians held. The connections between these different factors were investigated. A questionnaire covering items concerning demographic data, experience, knowledge about CSA, selfevaluated expertise and beliefs about CSA was given to social workers, child psychiatrists and psychologists working with children. The results showed that the clinicians relied more on their clinical experience than on scientific knowledge when evaluating their expertise as investigators of CSA. Furthermore, social workers possessed stronger attitudes in favor of children than the other groups, while child psychiatrists had more negative attitudes towards the criminal justice system. Male participants held less strong beliefs than female participants. The findings indicate that the education of CSA investigators should focus more on theoretical knowledge and decision making processes as well as the role of beliefs In Study II school and family counseling psychologists completed a Child Sexual Abuse Attitude and Belief Scale. Four CSA related attitude and belief subscales were identified: 1. The Disclosure subscale reflecting favoring a disclosure at any cost, 2. The Pro-Child subscale reflecting unconditional belief in children's reports, 3. The Intuition subscale reflecting favoring an intuitive approach to CSA investigations, and 4. The Anti Criminal Justice System subscale reflecting negative attitudes towards the legal system. Beliefs that were erroneous according to empirical research were analyzed separately. The results suggest that some psychologists hold extreme attitudes and many erroneous beliefs related to CSA. Some misconceptions are common. Female participants tended to hold stronger attitudes than male participants. The more training in interviewing children the participants have, the more erroneous beliefs and stronger attitudes they hold. Experience did not affect attitudes and beliefs. In Study III mental health professionals’ sensitivity to suggestive interviewing in CSA cases was explored. Furthermore, the effects of attitudes and beliefs related to CSA and experience with CSA investigations on the sensitivity to suggestive influences in the interview were investigated. Also, the effect of base rate estimates of CSA on decisions was examined. A questionnaire covering items concerning demographic data, different aspects of clinical experience, self-evaluated expertise, beliefs and knowledge about CSA and a set of ambiguous material based on real trial documents concerning an alleged CSA case was given to child mental health professionals. The experiment was based on a 2 x 2 x 2 x 2 (leading questions: yes vs no) x (stereotype induction: yes vs no) x (emotional tone: pressure to respond vs no pressure to respond) x (threats and rewards: yes vs no) between-subjects factorial design, in which the suggestiveness of the methods with which the responses of the child were obtained were varied. There was an additional condition in which the material did not contain any interview transcripts. The results showed that clinicians are sensitive only to the presence of leading questions but not to the presence of other suggestive techniques. Furthermore, the clinicians were not sensitive to the possibility that suggestive techniques could have been used when no interview transcripts had been included in the trial material. Experience had an effect on the sensitivity of the clinicians only regarding leading questions. Strong beliefs related to CSA lessened the sensitivity to leading questions. Those showing strong beliefs on the belief scales used in this study were even more prone to prosecute than other participants when other suggestive influences than leading questions were present. Controversy exists regarding effects of experience and feedback on clinical decision making. In Study IV the impact of the number of handled cases and of feedback on the decisions in cases of alleged CSA was investigated. One-hundred vignettes describing cases of suspected CSA were given to students with no experience with investigating CSA. The vignettes were based on statistical data about symptoms and prevalence of CSA. According to the theoretical likelihood of CSA the children described were categorized as abused or not abused. The participants were asked to decide whether abuse had occurred. They were divided into 4 groups: one received feedback on whether their decision was right or wrong, one received information about cognitive processes involved in decision making, one received both, and one did not receive feedback at all. The results showed that participants who received feedback on their performance made more correct positive decisions and participants who got information about decision making processes made more correct negative decisions. Feedback and information combined decreased the number of correct positive decisions but increased the number of correct negative decisions. The number of read cases had in itself a positive effect on correct positive decision.
Resumo:
Neuropeptide Y (NPY) is a widely expressed neurotransmitter in the central and peripheral nervous systems. Thymidine 1128 to cytocine substitution in the signal sequence of the preproNPY results in a single amino acid change where leucine is changed to proline. This L7P change leads to a conformational change of the signal sequence which can have an effect on the intracellular processing of NPY. The L7P polymorphism was originally associated with higher total and LDL cholesterol levels in obese subjects. It has also been associated with several other physiological and pathophysiological responses such as atherosclerosis and T2 diabetes. However, the changes on the cellular level due to the preproNPY signal sequence L7P polymorphism were not known. The aims of the current thesis were to study the effects of the [p.L7]+[p.L7] and the [p.L7]+[p.P7] genotypes in primary cultured and genotyped human umbilical vein endothelial cells (HUVEC), in neuroblastoma (SK-N-BE(2)) cells and in fibroblast (CHO-K1) cells. Also, the putative effects of the L7P polymorphism on proliferation, apoptosis and LDL and nitric oxide metabolism were investigated. In the course of the studies a fragment of NPY targeted to mitochondria was found. With the putative mitochondrial NPY fragment the aim was to study the translational preferences and the mobility of the protein. The intracellular distribution of NPY between the [p.L7]+[p.L7] and the [p.L7]+[p.P7] genotypes was found to be different. NPY immunoreactivity was prominent in the [p.L7]+[p.P7] cells while the proNPY immunoreactivity was prominent in the [p.L7]+[p.L7] genotype cells. In the proliferation experiments there was a difference in the [p.L7]+[p.L7] genotype cells between early and late passage (aged) cells; the proliferation was raised in the aged cells. NPY increased the growth of the cells with the [p.L7]+[p.P7] genotype. Apoptosis did not seem to differ between the genotypes, but in the aged cells with the [p.L7]+[p.L7] genotype, LDL uptake was found to be elevated. Furthermore, the genotype seemed to have a strong effect on the nitric oxide metabolism. The results indicated that the mobility of NPY protein inside the cells was increased within the P7 containing constructs. The existence of the mitochondria targeted NPY fragment was verified, and translational preferences were proved to be due to the origin of the cells. Cell of neuronal origin preferred the translation of mature NPY (NPY1-36) when compared to the non neuronal cells that translated both, NPY and the mitochondrial fragment of NPY. The mobility of the mitochondrial fragment was found to be minimal. The functionality of the mitochondrial NPY fragment remains to be investigated. L7P polymorphism in the preproNPY causes a series of intracellular changes. These changes may contribute to the state of cellular senescence, vascular tone and lead to endothelial dysfunction and even to increased susceptibility to diseases, like atherosclerosis and T2 diabetes.
Resumo:
Työn tavoitteena on selvittää erilaisten työaikamallien ja henkilöstön määrän vaikutuksia Finnsteven henkilöstökustannuksiin ja ylitöiden määrään. Selvitystyö toteutetaan simuloimalla vaihtoehtoisia työaikamalleja ja henkilöstömääriä tilastollisten menetelmien avulla. Työn toisena tavoitteena on ehdottaa yritykselle toimintatapaa suorittaa lopullinen henkilöstöresurssien optimointi. Työn teoriaosuudessa esitellään aluksi yritystä ja sen toimintaympäristöä. Tämän jälkeen tarkastellaan nykyisen TE-sopimuksen mahdollistamia työaikamalleja. Seuraavaksi perustellaan käytettävät tilastolliset menetelmät ja tiedonkeruumenetelmät. Edetessään työ syventyy tarkastelemaan yrityksen tekemän työn kohdentumista aikatyöhön ja ylityöhön sekä viikonpäiville että työvuoroille. Lopuksi kuvataan työn optimoinnissa käytetty logiikka, analysoidaan saatuja tuloksia ja esitellään optimointityökalun toteutussuunnitelma. Diplomityössä tehdyn selvityksen mukaan satamatyössä tehdään nykyisellään erittäin paljon ylitöitä. Siten työaikamallien optimointi on perusteltua. Optimoinnilla saavutettavat potentiaaliset kustannussäästöt ovat erittäin huomattavia. Lopullinen optimointi on haastava tehtävä, jota henkilöstöhallinto ei pysty ratkaisemaan pelkkään kokemukseensa luottaen. Tuotannonsuunnittelun avuksi tarvitaan täten työkalu, joka palvelee paitsi mallien luontia, toimii suunnittelun apuna jatkossakin.
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This project addresses methodological and technological challenges in the development of multi-modal data acquisition and analysis methods for the representation of instrumental playing technique in music performance through auditory-motor patterning models. The case study is violin playing: a multi-modal database of violin performances has been constructed by recording different musicians while playing short exercises on different violins. The exercise set and recording protocol have been designed to sample the space defined by dynamics (from piano to forte) and tone (from sul tasto to sul ponticello), for each bow stroke type being played on each of the four strings (three different pitches per string) at two different tempi. The data, containing audio, video, and motion capture streams, has been processed and segmented to facilitate upcoming analyses. From the acquired motion data, the positions of the instrument string ends and the bow hair ribbon ends are tracked and processed to obtain a number of bowing descriptors suited for a detailed description and analysis of the bow motion patterns taking place during performance. Likewise, a number of sound perceptual attributes are computed from the audio streams. Besides the methodology and the implementation of a number of data acquisition tools, this project introduces preliminary results from analyzing bowing technique on a multi-modal violin performance database that is unique in its class. A further contribution of this project is the data itself, which will be made available to the scientific community through the repovizz platform.
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Print quality and the printability of paper are very important attributes when modern printing applications are considered. In prints containing images, high print quality is a basic requirement. Tone unevenness and non uniform glossiness of printed products are the most disturbing factors influencing overall print quality. These defects are caused by non ideal interactions of paper, ink and printing devices in high speed printing processes. Since print quality is a perceptive characteristic, the measurement of unevenness according to human vision is a significant problem. In this thesis, the mottling phenomenon is studied. Mottling is a printing defect characterized by a spotty, non uniform appearance in solid printed areas. Print mottle is usually the result of uneven ink lay down or non uniform ink absorption across the paper surface, especially visible in mid tone imagery or areas of uniform color, such as solids and continuous tone screen builds. By using existing knowledge on visual perception and known methods to quantify print tone variation, a new method for print unevenness evaluation is introduced. The method is compared to previous results in the field and is supported by psychometric experiments. Pilot studies are made to estimate the effect of optical paper characteristics prior to printing, on the unevenness of the printed area after printing. Instrumental methods for print unevenness evaluation have been compared and the results of the comparison indicate that the proposed method produces better results in terms of visual evaluation correspondence. The method has been successfully implemented as ail industrial application and is proved to be a reliable substitute to visual expertise.
Resumo:
The home as ethos, an ethical dimension of human beings, is this study’s focus of interest. Can the home as ethos comprise motive and driving force for a human being? This dissertation has a mainly hermeneutic approach with a Caring Science interpretive horizon. Firstly, the purpose of this study is to develop the concept “home” through etymological and semantic analysis. The concept’s Caring Science content is also investigated. Secondly, the purpose of this study is to investigate, through the use of a history of ideas method, how the home as ethos is made visible and evident in public health nurses’ caring during the first half of the 20th century. Which motives compromise the driving force behind public health nurses’ caring? Which idea patterns are stressed? Material for the study’s concept determination consists of tymological dictionaries as well as Swedish language dictionaries published from 1850 – 2001. The results of the concept determination provide a preliminary idea-model, where dimensions such as ethos as a human being’s innermost room, human beings’ manner of being, and the metaphor “my home is my castle” are stressed. These results comprise the background of the history of ideas portion of the study. The study’s history of ideas investigation occurs through the evaluation and interpretation of historical sources focusing on the caring provided by public health nurses. Public health nurses comprise both the context and prevalent traditions during the time-period studied. The historical sources consist of three different types of sources, namely textbooks, archived material, and the professional nursing journals Epione and Sairaanhoitajatarlehti. The purpose is to rediscover fundamental idea-patterns through the thematic structuring of the patterns appearing in the historical sources. Three main idea-patterns and underlying themes are rediscovered: love- a fire which burns inside human beings; reverence for human beings and home; and the honor of responsibility. The emerging patterns are tightly interwoven and form a pattern. A new interpretation occurs, widening the study’s horizon and leading to the emergence of the theory-model’s contours. The study’s theory-model is formed from three different levels. Ethos as a human being’s innermost room- the spirit, encompasses a human being’s value base and the spirit that he/she is permeated with. Fundamental values are converted into an internal ethic, becoming visible in human beings’ manner of being- the manner of conduct. The metaphor “my home is my castle”- the tone, symbolizes the room where a human being’s abstract or concrete being lives. The spirit, the ethos, is expressed in a home’s culture and atmosphere, that is to say the tone of a home or how one lives in a room. Communion is a significant component in the creation of a culture and atmosphere. This study’s theory-model gives rise to a new perspective that can generate new patterns of action. The study’s theory-model results in a new historically-based view that create new patterns of action in care and Caring Science today.
Resumo:
Neuromuscular blocking agents (NMBAs) are widely used in clinical anaesthesia and emergency medicine. Main objectives are to facilitate endotracheal intubation and to allow surgery by reducing muscle tone and eliminating sudden movements, which may otherwise lead to trauma and complications. The most commonly used NMBAs are non-depolarizing agents with a medium duration of action, such as rocuronium and cisatracurium. They bind to the acetylcholine receptors in the neuromuscular junction, thus inhibiting the depolarization of the postsynaptic (muscular) membrane, which is a prerequisite for muscle contraction to take place. Previously, it has been assumed that nitrous oxide (N2O), which is commonly used in combination with volatile or intravenous anaesthetics during general anaesthesia, has no effect on NMBAs. Several studies have since claimed that N2O in fact does increase the effect of NMBAs when using bolus administration of the relaxant. The effect of N2O on the infusion requirements of two NMBAs (rocuronium and cisatracurium) with completely different molecular structure and pharmacological properties was assessed. A closed-loop feedback controlled infusion of NMBA with duration of at least 90 minutes at a 90% level of neuromuscular block was used. All patients received total intravenous anaesthesia (TIVA) with propofol and remifentanil. In both studies the study group (n=35) received N2O/Oxygen and the control group (n=35) Air/Oxygen. There were no significant differences in the mean steady state infusion requirements of NMBA (rocuronium in Study I; cisatracurium in Study II) between the groups in either study. In Study III the duration of the unsafe period of recovery after reversal of rocuronium-induced neuromuscular block by using neostigmine or sugammadex as a reversal agent was analyzed. The unsafe period of recovery was defined as the time elapsed from the moment of no clinical (visual) fade in the train-of-four (TOF) sequence until an objectively measured TOF-ratio of 0.90 was achieved. The duration of these periods were 10.3 ± 5.5 and 0.3 ± 0.3 min after neostigmine and sugammadex, respectively (P < 0.001). Study IV investigated the possible effect of reversal of a rocuronium NMB by sugammadex on depth of anaesthesia as indicated by the bispectral index and entropy levels in thirty patients. Sugammadex did not affect the level of anaesthesia as determined by EEG-derived indices of anaesthetic depth such as the bispectral index and entropy.
Resumo:
The paper supports a dialectical interpretation of Wittgenstein's method focusing on the analysis of the conditions of experience presented in his Philosophical Remarks. By means of a close reading of some key passages dealing with solipsism I will try to lay bare their self-subverting character: the fact that they amount to miniature dialectical exercises offering specific directions to pass from particular pieces of disguised nonsense to corresponding pieces of patent nonsense. Yet, in order to follow those directions one needs to allow oneself to become simultaneously tempted by and suspicious of their all-too-evident "metaphysical tone" - a tone which, as we shall see, is particularly manifest in those claims purporting to state what can or cannot be the case, and, still more particularly, those purporting to state what can or cannot be done in language or thought, thus leading to the view that there are some (determinate) things which are ineffable or unthinkable. I conclude by suggesting that in writing those remarks Wittgenstein was still moved by an ethical project, which gets conspicuously displayed in these reiterations of his attempts to cure the readers (and himself) from some of the temptations expressed by solipsism.
Resumo:
OBJETIVO: A obesidade mórbida é uma doença crônica que se acompanha de várias complicações médicas e de uma menor esperança de vida, prejudicando o aspecto físico, emocional, econômico e social. As pesquisas clínicas e experimentais são amplamente justificadas nesta doença, considerando-se que a opção de tratamento operatório é recente. As gastroplastias e as derivações gástricas são algumas das modalidades terapêuticas propostas e produzem uma grande câmara gástrica remanescente, que em algumas técnicas fica totalmente excluída do trânsito alimentar. As possíveis alterações deste segmento, transformado em apêndice do sistema digestório, representam um vasto campo para pesquisa. Tivemos como objetivo avaliar o peso e as alterações da dosagem de gastrina sérica do rato, após denervação vagal troncular subdiafragmática, com exclusão da câmara gástrica e duodeno do trânsito alimentar do animal. MÉTODO: Foi realizada vagotomia troncular e exclusão gastroduodenal em cem ratos, dos quais trinta puderam ser estudados. Eram ratos machos adultos (Rattus Norvegicus Albinus), da linhagem Wistar, com peso médio de 378,67 g. Este estudo foi complementado pela dosagem sérica de gastrina por radioimunoensaio com I125 e duplo anticorpo para gastrina. RESULTADOS: O peso de todos os ratos estudados diminuiu em média de 378,67 g para 285,83 g. Os trinta animais perderam em média 92,83 g (-24,52%). Houve diferenças significativas entre o peso inicial dos animais e o peso final (p< 0,001). A gastrina sérica também diminuiu em vinte e um dos trinta ratos operados, caindo de 59,68 pg/ml para 46,77 pg/ml em média, correspondendo a uma diminuição de 12,91 pg (-19,73%) entre as duas médias (p< 0,001). A análise estatística teve como objetivo avaliar se houve diminuição nas médias das variáveis: peso e gastrina, medidas antes e depois da operação proposta. Para avaliar as diferenças entre as médias, utilizou-se o teste estatístico do T-Student. CONCLUSÕES: Houve uma diminuição significativa do peso e da dosagem de gastrina sérica do animal.
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OBJETIVOS: avaliar a acurácia diagnóstica da biópsia direcional assistida à vácuo (mamotomia), guiada por ultra-sonografia, no diagnóstico das lesões mamárias não palpáveis, comparando-a com a biópsia excisional, e estimar o valor terapêutico da mamotomia em lesões benignas não palpáveis. MÉTODOS: foram incluídas 114 pacientes, as quais apresentavam lesões mamárias não palpáveis, visíveis à ultra-sonografia. As pacientes foram encaminhadas devido mastalgia ou alteração mamográfica detectada previamente, com solicitação de avaliação ultra-sonográfica complementar. Todas foram submetidas à mamotomia guiada por ultra-sonografia com Mammotome® (Biopsys, Irvine, Califórnia), com sonda gauge 11. A biópsia excisional foi realizada com agulhamento prévio daquelas pacientes que apresentaram lesão residual após a mamotomia, ou seja, em 88 pacientes. Para comparar os resultados do material obtido por mamotomia com os da biópsia excisional foram calculados os índices de sensibilidade e especificidade, valores preditivos positivo e negativo, e a proporção de concordância. As sensibilidades, assim como as especificidades e as proporções de concordância dos dois exames, foram comparadas por meio da estatística de Wald, utilizando um modelo para dados categorizados. RESULTADOS: das 114 pacientes, 88 submeteram-se a biópsia excisional. As 26 restantes não apresentaram lesões pós-mamotomia, visíveis à ultra-sonografia, sendo seguidas por um ano sem alterações nos exames semestrais, tanto mamográficos quanto ultra-sonográficos. Tratava-se de lesões menores do que 1,5 cm de diâmetro. Dentre as 88 pacientes submetidas à biópsia excisional 69 apresentaram lesões benignas (78,4%) e, 19 (21,6%), malignas. A mamotomia diagnosticou 16 das lesões malignas, com três resultados falso-negativos e nenhum falso-positivo. Os resultados falsos ocorreram: nos primeiros casos realizados, mostrando a existência de curva de aprendizagem do método ou por dificuldade técnica, como o borramento da imagem ultra-sonográfica por sangramento. A sensibilidade e especificidade foram de 84,2 e 100%, respectivamente, com valores preditivos positivo de 100%, e negativo de 95,8%. A acurácia da mamotomia foi de 96,6%. As complicações foram raras, como, dois casos de hematomas, dos quais nenhum necessitou de drenagem cirúrgica; um caso de reflexo vaso-vagal, impedindo a conclusão do exame. Os resultados cosméticos foram bastante favoráveis devido às pequenas incisões (3 mm) e menor quantidade de tecido excisado. CONCLUSÃO: a mamotomia guiada por ultra-sonografia mostrou-se método diagnóstico com alta acurácia, podendo ser usado como terapêutico para as lesões benignas, com diâmetro menor do que 1,5 cm.
Resumo:
The melanocortin peptides, including melanocyte-stimulating hormones, α-, β- and γ-MSH, are derived from the precursor peptide proopiomelanocortin and mediate their biological actions via five different melanocortin receptors, named from MC1 to MC5. Melanocortins have been implicated in the central regulation of energy balance and cardiovascular functions, but their local effects, via yet unidentified sites of action, in the vasculature, and their therapeutic potential in major vascular pathologies remain unclear. Therefore, the main aim of this thesis was to characterise the role of melanocortins in circulatory regulation, and to investigate whether targeting of the melanocortin system by pharmacological means could translate into therapeutic benefits in the treatment of cardiovascular diseases such as hypertension. In experiments designed to elucidate the local effects of α-MSH on vascular tone, it was found that α-MSH improved blood vessel relaxation via a nitric oxide (NO)-dependent mechanism without directly contracting or relaxing blood vessels. Furthermore, α-MSH was shown to regulate the expression and function of endothelial NO synthase in cultured human endothelial cells via melanocortin 1 receptors. In keeping with the vascular protective role, pharmacological treatment of mice with α-MSH analogues displayed therapeutic efficacy in conditions associated with vascular dysfunction such as obesity. Furthermore, α-MSH analogues elicited marked diuretic and natriuretic responses, which together with their vascular effects, seemed to provide protection against sodium retention and blood pressure elevation in experimental models of hypertension. In conclusion, the present results identify novel effects for melanocortins in the local control of vascular function, pointing to the potential future use of melanocortin analogues in the treatment of cardiovascular pathologies.
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Apesar de forragens grosseiras e secas serem empregadas comumente na alimentação de vacas em várias regiões, especialmente durante o período seco, a compactação primária do abomaso tem sido pouco relatada no Brasil, provavelmente pela dificuldade de diagnóstico dos veterinários de campo. Este trabalho objetivou realizar um estudo retrospectivo sobre a compactação primária do abomaso em 14 bovinos no Estado de Pernambuco. Oito casos considerados moderados, sem grave distensão abdominal e sem compactação do rúmen, foram tratados conservativamente e quatro casos graves, com severa distensão abdominal e compactação do rúmen, foram tratados cirurgicamente. Um touro foi encaminhado para abate e uma vaca morreu antes de receber qualquer tratamento. O maior número de casos de compactação do abomaso ocorreu em bovinos da raça Holandesa com seis casos (42,9%), seguido por animais mestiços com cinco casos (35,8%) e as raças Pardo-Suiça, Nelore e Marchigiana com um caso cada (21,3%). A composição da alimentação oferecida caracterizou-se por conter fibra de baixa qualidade e variou bastante dentre os casos. Os sinais clínicos mais frequentes foram comportamento apático, desidratação, timpanismo ruminal associado à hipomotilidade, distensão abdominal, hipomotilidade intestinal e fezes escassas ou ausentes com presença de muco. Os achados hematológicos revelaram, na maioria dos casos, leucocitose por neutrofilia e hiperfibrinogenemia. Na análise do fluido ruminal havia comprometimento da dinâmica da flora e fauna microbiana, e elevação no teor de cloreto. O índice de recuperação clínica (4/8) e cirúrgica (2/4) observado neste estudo foi de 50%. As condutas clínica e cirúrgica permanecem como opções viáveis para o tratamento das compactações leves e severas, entretanto o prognóstico é considerado reservado, principalmente quando associado à gestação avançada.
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Background: Maternal diabetes affects many fetal organ systems, including the vasculature and the lungs. The offspring of diabetic mothers have respiratory adaptation problems after birth. The mechanisms are multifactorial and the effects are prolonged during the postnatal period. An increasing incidence of diabetic pregnancies accentuates the importance of identifying the pathological mechanisms, which cause the metabolic and genetic changes that occur in offspring, born to diabetic mothers. Aims and methods: The aim of this thesis was to determine changes both in human umbilical cord exposed to maternal type 1 diabetes and in neonatal rat lungs after streptozotocin-induced maternal hyperglycemia, during pregnancy. Rat lungs were used as a model for the potential disease mechanisms. Gene expression alterations were determined in human umbilical cords at birth and in rat pup lungs at two week of age. During the first two postnatal weeks, rat lung development was studied morphologically and histologically. Further, the effect of postnatal hyperoxia on hyperglycemia-primed rat lungs was investigated at one week of age to mimic the clinical situation of supplemental oxygen treatment. Results: In the umbilical cord, maternal diabetes had a major negative effect on the expression of genes involved in blood vessel development. The genes regulating vascular tone were also affected. In neonatal rat lungs, intrauterine hyperglycemia had a prolonged effect on gene expression during late alveolarization. The most affected pathway was the upregulation of extracellular matrix proteins. Newborn rat lungs exposed to intrauterine hyperglycemia had thinner saccular walls without changes in airspace size, a smaller relative lung weight and lung total tissue area, and increased cellular apoptosis and proliferation compared to control lungs, possibly reflecting an aberrant maturational adaptation. At one and two weeks of age, cell proliferation and secondary crest formation were accelerated in hyperglycemia-exposed lungs. Postnatal hyperoxic exposure, alone caused arrested alveolarization with thin-walled and enlarged alveoli. In contrast, the dual exposure of intrauterine hyperglycemia and postnatal hyperoxia resulted in the phenotype of thick septa together with arrested alveolarization and decreased number of small pulmonary arteries. Conclusions: Maternal diabetic environment seems to alter the umbilical cord gene expression profile of the regulation of vascular development and function. Fetal hyperglycemia may additionally affect the genetic regulation of the postnatal lung development and may actually induce prolonged structural alterations in neonatal lungs together with a modifying effect on the deleterious pulmonary exposure of postnatal hyperoxia. This, combined with the novel human umbilical cord gene data could serve as stepping stones for future therapies to curb developmental aberrations.
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The melanocortin system is an important regulator of feeding, energy metabolism,and cardiovascular function and it consists of the pro-opiomelanocortin (POMC) derived melanocyte stimulating hormones (α-, β- and γ-MSH) and their endogenous melanocortin receptors, MC1R to MC5R. In the hypothalamus, α-MSH reduces food intake, and increases energy expenditure and sympathetic tone by binding to MC4R. Mutations affecting the MC4R gene lead to obesity in mammals. On the other hand, the metabolic effects of MC3R stimulation using agonists such as the endogenously expressed γ-MSH have been less extensively explored. The main objective of this study was to investigate the long-term effects of increased melanocortin tone in key areas of metabolic regulation in the central nervous system (CNS) in order to investigate the sitespecific roles of both α-MSH and γ-MSH. The aim was to stereotaxically induce local overexpression of single melanocortin peptides using lentiviral vectors expressing α-MSH (LVi-α-MSH-EGFP) and γ-MSH (LVi-γ-MSH-EGFP). The lentiviral vectors were shown to produce a long-term overexpression and biologically active peptides in cell-based assays. The LVi-α-MSHEGFP was targeted to the arcuate nucleus in the hypothalamus of diet induced obese mice where it reduced weight gain and adiposity independently of food intake. When the nucleus tractus solitarus in the brainstem was targeted, the LVi-α-MSH-EGFP treatment was shown to cause a small decrease in adiposity, which did not impact weight development. However, the α-MSH treatment increased heart rate, which was attenuated by adrenergic receptor blockade indicative of increased sympathetic activity. The LVi-γ-MSH-EGFP was targeted to the hypothalamus where it decreased fat mass in mice eating the standard diet, but the effect was abated if animals consumed a high-fat Western type diet. When the diet induced obese mice were subjected again to the standard diet, the LVi-γ-MSH-EGFP treated animals displayed increased weight loss and reduced adiposity. These results indicate that the long-term central anti-obesity effects of α-MSH are independent of food intake. In addition, overexpression of α-MSH in the brain stem efficiently blocked the development of adiposity, but increased sympathetic tone. The evidence presented in this thesis also indicates that selective MC3R agonists such as γ-MSH could be potential therapeutics in combination with low fat diets.
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Ouabain is an endogenous substance occurring in the plasma in the nanomolar range, that has been proposed to increase vascular resistance and induce hypertension. This substance acts on the a-subunit of Na+,K+-ATPase inhibiting the Na+-pump activity. In the vascular smooth muscle this effect leads to intracellular Na+ accumulation that reduces the activity of the Na+/Ca2+ exchanger and to an increased vascular tone. It was also suggested that circulating ouabain, even in the nanomolar range, sensitizes the vascular smooth muscle to vasopressor substances. We tested the latter hypothesis by studying the effects of ouabain in the micromolar and nanomolar range on phenylephrine (PE)-evoked pressor responses. The experiments were performed in normotensive and hypertensive rats in vivo, under anesthesia, and in perfused rat tail vascular beds. The results showed that ouabain pretreatment increased the vasopressor responses to PE in vitro and in vivo. This sensitization after ouabain treatment was also observed in hypertensive animals which presented an enhanced vasopressor response to PE in comparison to normotensive animals. It is suggested that ouabain at nanomolar concentrations can sensitize vascular smooth muscle to vasopressor stimuli possibly contributing to increased tone in hypertension