1,720,995 research outputs found
Characterization of patients with severe bacterial infections and sepsis in large population cohorts. Studies of risk factors, genetics and biomarkers
Full text linkSevere bacterial infections leading to sepsis is one of the leading causes of hospitalization and death worldwide. While improved health care has led to reduced mortality, it has also led to a marked increase in the number of sepsis-survivors which has enormous consequences both on quality of life and cost to the society. The World Health Organization (WHO) has called for initiatives aimed at increasing our knowledge to contribute to reduce this burden.
Research on severe bacterial infections leading to sepsis has traditionally been focusing on the different causative microbes, however, increasing focus is now on the host, including assessment of different risk factors. Identifying and understanding these is mandatory when deciding which measures to implement and which resources to prioritize.
Epidemiology and identification of these risk factors requires the ability to make retrospective diagnosis of sepsis in large populations cohorts or in electronic health records. This heavily relies on the quality and our understanding of and access to these sources of information. This is a particular challenge in sepsis, as the disease is heterogenous and has no specific diagnostic test.
The HUNT population (Trøndelag Health Study) is a unique population cohort with >70,000 participants and over 1 million person-years follow up. This project´s overall aim was to use this population cohort to get an overview of the different sources of bacterial infections leading to sepsis, and then further on use this knowledge and include other patient cohorts, to identify high-risk groups by searching for and identifying important risk-factors associated with different bacterial infections.
In this work we discuss the difficulties of identifying people with sepsis, both bedside, clinically and in retrospect. We then use this knowledge to present different aspects of sepsis epidemiology in four different papers. First, we describe the burden of severe bacterial infections by investigating incidence-, mortality-, and readmission rates and proportions of positive blood cultures in the different foci of infection (paper 1). Then we investigate and explore different possible important risk factors such as common genetic variants and 3 potentially modifiable lifestyle factors in skin- and soft tissue infections (SSTIs) (paper 2), the influence of chronic kidney disease on the risk for bloodstream infections (BSI) and sepsis (paper 3), and finally, the potential role for uromodulin as a biomarker for risk of urinary tract infections (UTIs) (paper 4). The different epidemiological methods used, including descriptive epidemiology, classical epidemiology and genetic epidemiology using the fact that the participants in the HUNT population and other cohorts are genotyped, are also discussed.
In summary we identify important risk factors for bacterial infections and sepsis using various epidemiological methods. This could play a part on the ongoing work of dividing this heterogenous disease into different subclasses and can improve the chances of future clinical research being of use to the increasing number of sepsis patients
Causes and Consequences of Small Size at Birth: Maternal Glucose Tolerance and Vitamin B12 Levels in Pregnancy, and Later Brain Volumes and Cognitive Function in the Offspring
No full textSmall size at birth may be caused by restricted fetal growth or preterm birth. Each year, preterm birth and low birth weight (LBW) cause roughly half of the 2.9 million neonatal deaths globally. Additionally, small birth size has been associated with long-term outcomes such as all-cause mortality and reduced cognitive function. But when is a newborn too small? Some newborns may be physiologically small (e.g. small parents), while others are born small due to a pathological process. The latter is often referred to as fetal growth restriction (FGR). The aim of this thesis was to explore some potential causes and consequences of small birth size. We studied two potential causes of small birth size: maternal glucose tolerance and vitamin B12 (B12) levels in pregnancy. We also studied the association between fetal growth pattern and offspring cognitive function and regional brain volumes.
The first paper in this thesis was based on a large, long-term follow-up study in Scandinavia. The population was enriched with women at an increased risk of giving birth to a child with LBW. Ultrasound measurements were used to estimate fetal growth in the second and third trimesters, and an oral glucose tolerance test was performed in the third trimester. The difference between the two-hour and fasting blood glucose values was labeled delta (Δ) glucose. A total of 855 women were included in the study. We found that the most glucose tolerant women, identified by a low Δ glucose, were associated with an increased risk of carrying fetuses with suboptimal growth. These women also gave birth to thinner newborns, but of similar weight, compared with the other women.
Offspring of the women followed in the Scandinavian study were followed after birth. Cognitive function was assessed at five and nine years of age, and regional brain volumes were estimated at age 15 years. The second paper included 83 children born small-for-gestationalage (SGA; birth weight <10th percentile) at term and 105 non-SGA children. Based on serial ultrasound measurements, 13 children in the SGA-group were classified as FGR (SGA-FGR) and 36 were classified as non-FGR (SGA non-FGR). We found that children born SGA due to FGR (SGA-FGR) – but not those born constitutionally small (SGA non-FGR) – had impaired performance intelligence quotient scores and smaller thalamic and cerebellar white matter volumes compared with controls.
The last paper in this thesis is a systematic review where we evaluated the association between maternal vitamin B12 blood levels in pregnancy and newborn birth weight and length of gestation. Eligible studies provided individual patient data (IPD), and when IPD could not be provided, relevant estimates from individual studies were included in the analyses. Twentytwo eligible studies were identified, of which 18 were included in the meta-analysis (11,216 pregnancies; 94% of all eligible pregnancies). B12-deficiency in pregnancy was associated with an increased risk of preterm birth and LBW, but not SGA. The increased risk of preterm birth among B12-deficient women was similar in high-income countries and low- and middleincome countries.
This thesis suggests that pregnant women who have a high glucose tolerance may have an increased risk for carrying fetuses with suboptimal growth. Vitamin B12, however, seems to be associated with the length of gestation, but not fetal growth. The risk of reduced cognitive function and smaller regional brain volumes in childhood and adolescence seems to be higher among children born small due to restricted fetal growth than in other children born small
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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