1,720,959 research outputs found
Response to Stanich et al.: Correspondence regarding-PTEN hamartoma tumor syndromes in childhood-Description of two cases and a proposal for follow-up protocol
No full textThe follow-up protocol, which we describe in this study can serve as a practical proposal for clinicians, and as a basis for future studies. We strongly urge the clinician to start an early surveillance of the gastrointestinal tract including regular endoscopy. The main management goals in PHTS patients are to detect colon cancer early, and to prevent polyp-related complications (bowel obstruction from intussusception). The presence of multiple nonmalignant polyps in patients with PTEN mutations may complicate noninvasive methods of colon evaluation [Tan et al., 2012]. In addition, there is a high variability in severity of polyps progression, and the malignant potential of these lesions is not well characterized. More frequent colonoscopy should be considered for patients with a heavy polyp burden [Tan et al., 2012]. Some patients may require more frequent endoscopy if they show an accelerated rate of polyps development [Septer et al., 2013]. It is clear that an appropriate surveillance plan is influenced by the patient's endoscopic and histologic findings, as well as the personal medical and family history features, and physical manifestations. Nevertheless, further prospective studies are needed to assess the timing and the appropriateness of colorectal cancer screening in these patients
12q14.3 microdeletion involving HMGA2 gene cause a Silver-Russell syndrome-like phenotype: A case report and review of the literature
Full text linkBackground: Silver-Russell Syndrome (SRS) is a genetic disorder characterized by intrauterine and postnatal growth restriction and normal head circumference with consequent relative macrocephaly. Addictional findings are protruding forehead in early life, body asymmetry (of upper and lower limbs) and substantial feeding difficulties. Although several genetic mechanisms that cause the syndrome are known, more than 40% of patients with a SRS-like phenotype remain without an etiological diagnosis. In the last few years, different clinical reports have suggested that mutations or deletions of the HMGA2 gene can be responsible for a SRS-like phenotype in patients with negative results of the common diagnostic tests for this syndrome. Case presentation: We present a 3-year-old male patient with clinical diagnosis of Silver-Russell Syndrome (SRS) associated with a de novo heterozygous deletion of the long arm of the chromosome 12 (12q14.3) encompassing the HMGA2 gene. Conclusions: Our report confirms the etiological role of HMGA2 as a disease gene in the development of a SRS-like phenotype
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
PTEN hamartoma tumor syndromes in childhood: description of two cases and a proposal for follow-up protocol
Full text linkPTEN hamartoma tumor syndromes (PHTS) are a spectrum of
hamartomatous overgrowth syndromes associated with germline
mutations in the tumor suppressor PTEN gene located on
10q23.3. It is widely accepted that two of these disorders,Cowden
syndrome and Bannayan–Riley–Ruvalcaba syndrome, are allelic
conditions. BecausePTENmutations are not identifiable in every
case of the PHTS phenotype, the inability to detect a mutation
within thePTENgene does not invalidate the clinical diagnosis of
Cowden syndrome, or Bannayan–Riley–Ruvalcaba syndrome, in
patients who meet diagnostic criteria for these disorders. PTEN
mutations are associated with an increased risk for developing
breast, thyroid, endometrial, and sometimes renal cancers. Thus,
cancer surveillance is the cornerstone of PHTS patient management.
Although a consensus cancer surveillance protocol has not
been formally instituted, all PTEN mutation carriers should
adopt the cancer surveillance strategies proposed for patients
with Cowden syndrome. In addition, because gastrointestinal
and vascular complications can be more severe in Bannayan–
Riley–Ruvalcaba syndrome than in Cowden syndrome, patients
with Bannayan–Riley–Ruvalcaba syndrome should be monitored
from this point of view too. In this study, we report on
two cases with Bannayan–Riley–Ruvalcaba phenotype that
showed two different PTEN mutations.Wealso propose practice
recommendations for management of PHTS patient
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
Susceptibility to heart defects in down syndrome is associated with single nucleotide polymorphisms in has 21 interferon receptor cluster and vegfa genes
Full text linkBackground: Congenital heart defects (CHDs) are present in about 40–60% of newborns with Down syndrome (DS). Patients with DS can also develop acquired cardiac disorders. Mouse models suggest that a critical 3.7 Mb region located on human chromosome 21 (HSA21) could explain the association with CHDs. This region includes a cluster of genes (IFNAR1, IFNAR2, IFNGR2, IL10RB) encoding for interferon receptors (IFN-Rs). Other genes located on different chromosomes, such as the vascular endothelial growth factor A (VEGFA), have been shown to be involved in cardiac defects. So, we investigated the association between single nucleotide polymorphisms (SNPs) in IFNAR2, IFNGR2, IL10RB and VEGFA genes, and the presence of CHDs or acquired cardiac defects in patients with DS. Methods: Individuals (n = 102) with DS, and age-and gender-matched controls (n = 96), were genotyped for four SNPs (rs2229207, rs2834213, rs2834167 and rs3025039) using KASPar assays. Results: We found that the IFNGR2 rs2834213 G homozygous genotype and IL10RB rs2834167G-positive genotypes were more common in patients with DSand significantly associated with heart disorders, while VEGFA rs3025039T-positive genotypes (T/*) were less prevalent in patients with CHDs. Conclusions: We identified some candidate risk SNPs for CHDs and acquired heart defects in DS. Our data suggest that a complex architecture of risk alleles with interplay effects may contribute to the high variability of DS phenotypes
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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