1,721,034 research outputs found
Preterm Birth
Full text linkThe preterm parturition syndrome is one of the major obstetrical complications of our time. Understanding the mechanisms leading to prematurity may assist the clinician to tailor the desired treatment that is suitable to the mechanisms leading to preterm birth in a specific patient. In the first section of this book we present an update on the association of periodontal disease, maternal stress, and activation of the hemostatic system and preterm parturition. The second section of the book deals with short and long term effects of prematurity, with a long term aspect of late preterm birth. This book will expand the dialogue between obstetricians, pediatricians and other disciplines regarding the diagnosis, treatment and prevention of prematurity
Preterm Birth
No full textThe preterm parturition syndrome is one of the major obstetrical complications of our time. Understanding the mechanisms leading to prematurity may assist the clinician to tailor the desired treatment that is suitable to the mechanisms leading to preterm birth in a specific patient. In the first section of this book we present an update on the association of periodontal disease, maternal stress, and activation of the hemostatic system and preterm parturition. The second section of the book deals with short and long term effects of prematurity, with a long term aspect of late preterm birth. This book will expand the dialogue between obstetricians, pediatricians and other disciplines regarding the diagnosis, treatment and prevention of prematurity
Preeclampsia/eclampsia: the conceptual evolution of a syndrome
No full textPreeclampsia, one of the most enigmatic complications of pregnancy, is considered a pregnancy-specific disorder caused by the placenta and cured only by delivery. This article traces the condition from its origin—once thought to be a disease of the central nervous system, recognized by the occurrence of seizures (ie eclampsia)—to the present time when preeclampsia is conceptualized primarily as a vascular disorder. We review the epidemiologic data that led to the recommendation to use diastolic hypertension and proteinuria as diagnostic criteria, given that their combined presence was associated with an increased risk of fetal death and the birth of small-for-gestational-age neonates. However, preeclampsia is a multi-systemic disorder with protean manifestations, and the condition can be present even in the absence of hypertension and proteinuria. Toxin(s) that gain access to the maternal circulation have been proposed to mediate the clinical manifestations—hence, the term “toxemia of pregnancy,” which was used for several decades. The search for putative toxins has challenged investigators for more than a century, and a growing body of evidence suggests that products of an ischemic or a stressed placenta are responsible for the vascular changes that characterize the syndrome. The discovery that the placenta can produce anti-angiogenic factors, which regulate endothelial cell function and induce intravascular inflammation, has been a major step forward in the understanding of preeclampsia. We view the release of anti-angiogenic factors by the placenta as an adaptive response to improve uterine perfusion by modulating endothelial function and maternal blood pressure. However, this homeostatic response can become maladaptive and lead to the damage of target organs during pregnancy or the postpartum period. Early-onset preeclampsia has many features in common with atherosclerosis, while late-onset disease appears to result from a mismatch of fetal demands and maternal supply: in other words, a metabolic crisis. Preeclampsia, as it is understood today, is essentially vascular dysfunction unmasked, or caused, by pregnancy that results in a multi-systemic disorder. A subset of patients diagnosed with preeclampsia are at greater risk for the subsequent development of hypertension, ischemic heart diseases, heart failure, vascular dementia, and end-stage renal disease. However, these adverse events may be the result of a preexisting vascular pathologic process; it is not known if the occurrence of preeclampsia by itself increases the baseline risk. The understanding of preeclampsia is a healthcare priority
Ultrasonographic approach to diagnosis of fetal inflammatory response syndrome: a tool for at-risk fetuses?
No full textPreterm parturition is a syndrome that may result from many underlying mechanisms. Infection and inflammation are the prominent ones. Intrauterine infection and inflammation have an effect akin to sepsis, and that is similar to systemic inflammatory response in adults. Indeed, there is evidence to support the association of a fetal inflammatory response syndrome (FIRS) to systemic infection and inflammation. The utilization of invasive procedures for the prenatal diagnosis of FIRS is associated with a risk for complications resulting from the invasive method. The progress in the imaging quality of obstetrical ultrasound and the development of novel methods for functional anatomical assessment of the fetal organs may help to identify, noninvasively, fetuses at risk for FIRS in patients presenting with preterm labor. We review the studies describing advanced sonographic modalities and the imaging findings in the heart, thymus, kidney, adrenal glands, and spleen of these fetuses
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
Maternal plasma cytokines and the subsequent risk of uterine atony and postpartum hemorrhage
No full textObjectives: To determine whether the maternal plasma concentrations of cytokines are higher in pregnant women with postpartum hemorrhage (PPH) compared to pregnant women without PPH.Methods: A retrospective case-control study included 36 women with PPH and 72 matched controls. Cases and controls were matched for gestational age at delivery, labor status, delivery route, parity, and year of sample collection. Maternal plasma samples were collected up to 3 days prior to delivery. Comparison of the plasma concentrations of 29 cytokines was performed by using linear mixed-effects models and included adjustment for covariates and multiple testing. A false discovery rate adjusted p-value <0.1 was used to infer significance. Random forest models with evaluation by leave-one-out and 9-fold cross-validation were used to assess the combined value of the proteins in predicting PPH.Results: Concentrations of interleukin (IL)-16, IL-6, IL-12/ IL-23p40, monocyte chemotactic protein 1 (MCP-I), and IL-1 beta were significantly higher in PPH than in the control group. This difference remained significant after adjustment for maternal age, clinical chorioamnionitis, and preeclampsia. Multi-protein random forest proteomics models had moderate cross-validated accuracy for prediction of PPH [area under the ROC curve, 0.69 (0.58-0.81) by leave-one-out cross validation and 0.73 (0.65-0.81) by 9-fold cross-validation], and the inclusion of clinical and demographic information did not increase the prediction performance.Conclusions: Pregnant women with severe PPH had higher median maternal plasma concentrations of IL-16, IL-6, IL-12/IL-23p40, MCP-1, and IL-1 beta than patients without PPH. These cytokines could serve as biomarkers or their pathways may be therapeutic targets
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
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