1,720,987 research outputs found
Single-nucleotide polymorphisms in genes involved in placental function and unexplained stillbirth.
No full textOBJECTIVE: The purpose of this study was to evaluate the association between unexplained stillbirth (SB) and single-nucleotide polymorphisms (SNPs) in genes involved in placental function using a well-characterized cohort.
STUDY DESIGN: Placentas were obtained from 50 unexplained SB and 46 live birth controls. Classification of stillbirth was by Wigglesworth criteria. SBs were stratified by weight: appropriate (AGA-SB) and small for gestational age (SGA-SB, less than the 10th percentile) and gestational age: before 32 and after 32 weeks. Placental DNA was extracted and various SNPs in the endothelial nitric oxide synthase (eNOS), Klotho, hypoxic inducible factor-1α, and and tumor necrosis factor-α genes were evaluated.
RESULTS: None of the SNPs were associated with SB overall. Significantly different genotype distribution emerged for eNOS-SNP rs1800783 when comparing AGA-SB with SGA-SB and control (P = .004). Its allele-A was more frequent in AGA-SB compared with both controls (P = .03) and SGA-SB (P = .001). No differences were seen accordingly to gestational age.
CONCLUSION: Unexplained stillbirth in the setting of adequate growth is associated with carrier of allele A of rs1800783 eNOS gene in the placenta
Regional and racial/ethnic differences in perinatal interventions among periviable gestations
No full textOBJECTIVE: To examine whether there are: 1) regional differences in three perinatal interventions that reflect active treatment among periviable gestations and 2) racial–ethnic differences in the receipt of these perinatal interventions after accounting for hospital region.
METHODS: We conducted a retrospective study on neonates born at 776 U.S. centers that participated in the Vermont Oxford Network (2006–2017) with a gestational age of 22–25 weeks. The primary outcome was postnatal life support. Secondary outcomes included maternal administration of antenatal corticosteroids and cesarean delivery. We examined rates and 99% CI of the three outcomes by region. We also calculated the adjusted relative risks (aRRs) and 99% CIs for the three outcomes by race and ethnicity within each region using modified Poisson regression models with robust variance estimation.
RESULTS: Major regional variation exists in the use of the three interventions at 22 and 23 weeks of gestation but not at 24 and 25 weeks. For example, at 22 weeks of gestation, rates of life support in the South (38.3%; 99% CI 36.3–40.2) and the Midwest (32.7%; 99% CI 30.4–35.0) were higher than in the Northeast (20.2%; 99% CI 17.6–22.8) and the West (22.2%; 99% CI 20.0–24.4). Particularly in the Northeast, black and Hispanic neonates born at 22 or 23 weeks of gestation had a higher provision of postnatal life support than white neonates (at 22 weeks: black: aRR 1.84 [99% CI 1.33–2.56], Hispanic: aRR 1.80 [1.23–2.64]; at 23 weeks: black: aRR 1.14 [99% CI 1.08–1.20], Hispanic: aRR 1.12 [1.05–1.19]). In the West, black and Hispanic neonates born at 23 weeks of gestation also had a higher provision of life support (black: aRR 1.11 [99% CI 1.03–1.19]; Hispanic: aRR 1.10 [1.04–1.16]).
CONCLUSION: Major regional variation exists in perinatal interventions when managing 22- and 23-week neonates. In the Northeast and the West regions, minority neonates born at 22 and 23 weeks of gestation had higher provision of postnatal life support
L-arginine supplementation in patients with gestational hypertension: A pilot study
No full textObjective: To evaluate the effects of L-arginine (L-Arg) supplementation on clinical outcomes and blood pressure (BP) changes in patients with gestational hypertension. Methods: Patients with gestational hypertension and proteinuria (n = 28, > 300 mg/ 24 h) and those without proteinuria (n = 46) were randomized in a double-blind design to receive either L-Arg (20g/500 mL intravenously daily, for 5 days followed by 4g/day orally for 2 weeks) or placebo (PL). The primary outcome variable was time from randomization to delivery (Latency). Automated BP readings were obtained every 2 hours, between 8.00 am and 8.00 pm daily, untill the sixth day after treatment. Results: At inclusion, gestational age and proportions of patients with proteinuria did not differ significantly between the PL and L-Arg group, Latency was significantly longer in the L-Arg group compared with the PL group (19.5 +/- 16.9 vs. 31.7 +/- 25.2 days; p = 0.008). Compared with baseline, both systolic and diastolic BP 6 days after treatment were significantly reduced in the L-Arg group but not in the PL group. The subgroup of patients without proteinuria randomized to the group receiving L-Arg showed a trend to prolong pregnancy, to attenuate the evolution to PE, and to reduce the rate of low birth weight. Conclusions: The treatment with L-Arg seems promising in prolonging pregnancy and reducing blood pressure, particularly in patients with gestational hypertension and without proteinuria. This benefit should be confirmed in larger studies with the power to evaluate the effectiveness of L-Arg in preventing the development to preeclampsia
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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