1,720,990 research outputs found
Genetic syndromes involving hearing
No full textObjective: The fundamental processes involved in the mechanism of hearing seem to be controlled by hundreds of genes and hereditary hearing impairment may be caused by a large variety of genetic mutations in different genes. Approximately 150 loci for monogenic disorders (for which hearing loss is the only manifestation and therefore is nonsyndromic) and for syndromic disorders, have been mapped to the human
genome. The identification of these genes and unctional analysis of the proteins they encode, are paving the way towards a better understanding of the physiology and pathophysiology of the auditory system. To date,approximately50 causative genes have been identified.
Methods: The clinicaland neuroradioldical findings of syndromal hearing impairment areanalysed.
Results: This paper presents an updated report on genetic syndromes in which a hearing impairment is involved, with a particular attention to the ones associated with external ear and craniofacial malformations.
Conclusions: Concepts in human genetics are rapidly evolving together with technologies. The concept itself of gene is changing. A genetic diagnosis of syndromal hearing impairment has many practical consequences: it can implies specific prognosis,specific management, specific recurrence risk in relatives and,if the diagnosis
is confirmed at the molecular level,possibility of a specific early prenatal diagnosis for severe syndromes.It is important to highlight the necessity that the pediatric otolaryngologist must have a close collaboration with a clinical geneticist and a neuroradiologist
Clinical and radiological evaluation in children with microtia
No full textThe management of a child with congenital ear malformation, in particular if the external ear is severely involved, is difficult because of the complexity of the therapeutic problem, and that of parental anxiety. It is very important to plan a complete therapeutic/habilitative programme as soon as possible, even if surgical procedures are delayed. Diagnostic imaging plays an important role in the global assessment of a child with microtia, in order to diagnose possible associated external auditory canal, middle and inner ear malformations. For these reasons our diagnostic protocol for children with microtia includes otological and audiological evaluation, clinical genetics and radiological imaging, from the neonatal period. Here, data are reported on 27 children with microtia who completed the diagnostic protocol. In eight of 27 cases microtia was bilateral: in unilateral cases the right side was affected more frequently. Other congenital malformations were diagnosed in 41% of cases. A high correlation between the degree of microtia and the frequency of external and middle ear dysplasias was found, in accordance with larger studies of the literature. Inner ear malformations were found less frequently, but without apparent correlation with the degree of microtia. The fact that children with microtia may also have severe inner ear malformations is emphasized
In vitro short-term test evaluation of catecholestrogens genotoxicity
No full textEstrogens are indicated as being the most important etiological factors for the development and progression of breast cancer. The implication of estrogen in breast cancer has been associated mostly with the estrogen receptors that mediate cell proliferation. Evidence also exists to support the hypothesis of a direct role of estrogens as tumor initiators. However, the role of estrogen genotoxicity in breast cancer is still questionable. In this study the genotoxic activity of catecholestrogens and 16alpha-hydroxy estrone has been investigated by performing Salmonella strain TA98 and TA100 Ames tests, sister chromatide exchange assays (SCE) and micronucleus assays on human peripheral lymphocytes (CBMN and ARA/CBMN). We found a lack of positive results with micronucleus assays, except for 2-hydroxy estradiol (2-OHE(2)), which shows a peculiar "bell shaped" trend of micronucleus number versus concentrations. SCE assay suggests weak genotoxic activity of all tested catechol metabolites, except 4-hydroxy estrone (4-OHE(1)), which also showed negative results by ARA/CBMN. In this open debate, our results support the hypothesis of a weak genotoxicity, not correlated with the carcinogenetic potential of estrogens
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
A 931 + 2T-->C transition in one COL1A2 allele causes exon 16 skipping in PRO alpha 2(I) mRNA and produces moderately severe OI.
No full textA familial case of NOG-related symphalangism spectrum disorder due to a novel NOG variant
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