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Calibre vascular retiniano e a pressão arterial medida por monitoramento ambulatorial da pressão arterial
Full text linkÉ bem conhecido que alterações vasculares iniciam como um processo silencioso e assintomático. A identificação precoce de anormalidades vasculares na retina em pacientes assintomáticos pode permitir a detecção de pacientes em risco de desenvolver DCV. Por prover visualização direta do leito vascular, a retina pode ser estudada não invasivamente mostrando o grau de acometimento da microcirculação. Avanços nas técnicas de fotografia retiniana e de análise digital de imagem tem permitido a mensuração objetiva de alterações vasculares da retina. Com isso, é possível quantificar anormalidades na microvasculatura retiniana, imprescindível para o estudo da fisiopatologia da hipertensão arterial sistêmica, bem como para a avaliação da associação com doença cardiovascular. Um software desenvolvido pela autora desta tese e colaboradores é capaz de medir calibre de arteríolas e vênulas de retinografias digitalizadas. Esse software, nomeado Retinal Analyser System (RAS), foi atualizado e houve a inclusão e testagem de um fator de escala ou calibração, apresentado no Artigo 1 dessa tese. Os métodos de análise de imagens da retina utilizados para medir calibre dos vasos retinianos não determinam exatamente o que está sendo medido. Assim, havia necessidade de investigar se o calibre medido no software RAS corresponde ao lúmen vascular somente ou se inclui a parede vascular. O Artigo 2 dessa tese apresenta a comparação de medidas de calibre de vasos retinianos, em retinografias coloridas com angiografias fluoresceínicas. Nesse artigo concluímos que, como as diferenças encontradas entre os dois métodos foram muito pequenas, o método microdensitométrico mede o lúmen vascular. Os calibres vasculares retinianos avaliados quantitativamente por métodos digitalizados tem mostrado uma associação significativa com incidência e gravidade da hipertensão arterial casual. No entanto, nas últimas décadas, tem sido discutido o valor da medida casual da pressão arterial para fins prognósticos. Em função da variação contínua da pressão arterial, de momento a momento, de acordo com as atividades do indivíduo, novos métodos podem complementar a avaliação através de medidas repetidas da pressão arterial, permitindo a detecção da pressão arterial usual. Tendo em vista essas considerações, o Artigo 3 dessa tese avaliou a associação entre os diferentes parâmetros da pressão arterial, medida pela MAPA, e os calibres vasculares retinianos. A relação entre pressão arterial e calibre arteriolar e venular da retina no momento da obtenção retinografia também foi estudada. Demonstramos que a pressão diastólica média das 24 horas, da vigília e do sono teve associação inversa e significativa com calibre arteriolar e razão arterio-venosa, mas não com calibre venular. A pressão arterial medida na hora da retinografia não mostrou associação com o calibre dos vasos retinianos. Assim concluímos que a associação entre o calibre arteriolar dos vasos retinianos e a pressão arterial não é influenciada pela variação instantânea da pressão arterial e, provavelmente, depende de lesões histológicas da parede arteriolar secundária à hipertensão sustentada. Através da MAPA também é possível avaliarmos a variação temporal da pressão arterial ao longo de um período de 24 horas, e assim estudar o ritmo circadiano e a ritimicidade da pressão arterial. Uma maneira de analisar a ritimicidade da pressão arterial é através do método Cosinor, um método de análise de regressão periódica, baseada na adaptação da função do coseno, para valores da pressão arterial com período de 24 horas. O método Cosinor gera, em cada elemento (indivíduo ou população), os seguintes parâmetros de validação do ritmo circadiano: MESOR (sigla em inglês para média do ritmo ajustada estatísticamente), acrofase e amplitude. O estudo do ritmo circadiano da pressão arterial, avaliado pela da análise de cosinor, e sua associação com os calibres vasculares retinianos, resultou no artigo 4 dessa tese. Nesse artigo, mostramos que o MESOR associa-se significativa e inversamente com calibre arteriolar, com uma magnitude de 0.8 a 1 micron de redução no calibre para um aumento de 10 mmHg do MESOR da pressão arterial. O calibre venular não mostrou associação com o MESOR. Também usamos a análise de Cosinor para população e avaliamos as diferenças nos ritmos da pressão arterial entre as populações do primeiro e dos demais quintis de calibre vascular. Através desta análise observamos que amplitude e acrofase da pressão arterial são estatisticamente diferente entre as populações do primeiro e demais quintis de calibre venoso, mas não arteriolar. Em resumo, enquanto o MESOR está associado ao calibre arteriolar, a amplitude e a acrofase estão associadas ao calibre venular. Concluindo, essa tese mostra, através de seus 4 artigos, a aplicação do software RAS para medida de calibres vasculares retinianos e a associação dessas medidas com pressão arterial, em uma população de pacientes hipertensos. A associação entre o calibre vascular retiniano, a pressão arterial medida 24 horas e o seu ritmo, demonstrada nessa tese, fortalece a hipótese que a avaliação da microvasculatura retiniana pode ser um marcador clínico importante de lesão em órgão.It is well known that vascular changes begin as a silent and asymptomatic process. Early identification of retinal vascular abnormalities in asymptomatic patients may allow the detection of patients at risk. By providing unique visualization of the vascular bed, the retina can be studied no invasively and show the degree of microcirculation involvement. Advances in techniques of retinal photography and digital image analysis have allowed objective measurement of retinal vascular changes. Thus, it is possible to quantify abnormalities in the retinal microvasculature, essentially to study hypertension pathophysiology, and to assess its association to cardiovascular disease. Software developed by our research group is able to measure the caliber of arterioles and venules of digitized fundus. This software, named Retinal Analyzer System (RAS), has been updated by including and testing a scale factor, presented in Article 1 of this thesis. The current methods of image analysis used to measure the caliber of retinal vessels do not determine exactly what is being measured. Thus there was need to investigate whether the caliber measured in RAS software corresponds to the vascular lumen only or whether it includes the vascular wall. Article 2 of this thesis presents a comparison of the measurements of retinal vessels calibers in color fundus photography to those in fluorescein angiography. In this article we show that the differences found between the two methods were very small, and concluded that the microdensitometry method measures mainly the vascular lumen. The retinal vascular calibers measured quantitatively by microdensitometric methods have shown a significant association with incidence and severity of hypertension. However, studies evaluating these associations are based on casual blood pressure and, in recent decades, it has been discussed the value of casual blood pressure measurement. In light of continuous variation in blood pressure from moment to moment, according to the individual's activities, new methods can complement the assessments through repeated measurements of blood pressure, allowing the detection of usual blood pressure. Given these considerations, Article 3 of this thesis examined the association between different parameters of the blood pressure measured by ABPM, and retinal vascular caliber. The relationship between blood pressure at the time of retinography acquisition and retinal arteriolar and venular caliber was also studied. We show that the mean 24 hours, daytime and night time diastolic blood pressure were significantly and inversely associated with arteriolar caliber and arteriovenous ratio, but not with venular caliber. The pressure measured at the time of acquisition of the fundus showed no association with the caliber of retinal vessels, thus the association between arteriolar retinal vessels caliber and blood pressure is not influenced by instantaneous variation of blood pressure and probably depends of histological damage of arteriolar wall secondary to sustained hypertension. Using ABPM is also possible to evaluate the temporal variation of blood pressure over a period of 24 hours, and then study the circadian rhythm of blood pressure. One way to analyze the blood pressure rhythm is using the Cosinor method, a method of periodic regression analysis, based on the adaptation of the cosine function, for values of blood pressure with 24-hour period. The method Cosinor generates the following validation parameters of the circadian rhythm: MESOR (acronym for "Midline Estimated Statistic Of Rhythm"), acrophase and amplitude. The study of circadian rhythm of blood pressure, as assessed by analysis COSINOR and its association with retinal vascular caliber, resulted in Article 4 of this thesis. In this paper we show that MESOR is associated significantly and inversely with arteriolar caliber, with a magnitude of 0.8 to 1 micron reduction to an increase of 10 mmHg of blood pressure MESOR. The venular caliber was not associated with MESOR. We also use the Cosinor analysis to study differences in the rhythms of blood pressure among populations in the first quintile and the rest quintiles of vascular caliber. Through this analysis we found that amplitude and acrophase of blood pressure were statistically different between the populations of the first and the other quintiles of venous caliber, but not arterioles. In conclusion, this thesis shows, through its four articles, the application of RAS software to measure retinal vascular caliber and the association of these measurements with blood pressure in a population of hypertensive patients. The association between retinal vascular calibers, blood pressure measured 24 hours and rhythm, as demonstrated in this thesis, strengthens the hypothesis that assessment of the retinal microvasculature may be an important clinical marker of organ damage
Trabeculoplastia seletiva a laser guiada por computador (PSLT) no tratamento da hipertensão ocular e do glaucoma de ângulo aberto comparado a colírios análogos de prostaglandina: um ensaio clínico randomizado de não inferioridade
Full text linkAvaliação automatizada de estreitamento arteriolar em retinografias digitalizadas : desenvolvimento e validação do método
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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