92 research outputs found
The Postprocessed Mixed Finite-Element Method for the Navier--Stokes Equations
A postprocessing technique for mixed finite-element methods for the incompressible
Navier–Stokes equations is studied. The technique was earlier developed for spectral and standard
finite-element methods for dissipative partial differential equations. The postprocessing amounts to
solving a Stokes problem on a finer grid (or higher-order space) once the time integration on the
coarser mesh is completed. The analysis presented here shows that this technique increases the
convergence rate of both the velocity and the pressure approximations. Numerical experiments are
presented that confirm both this increase in the convergence rate and the corresponding improvement
in computational efficiency.DGICYT BFM2003-0033
Clinical aspects of usher syndrome and the USH2A gene in a cohort of 433 patients
IMPORTANCE A new statistical approach is needed to describe the clinical differences
between type I and type II Usher syndrome and between the 2 most frequent mutations in
the USH2A gene.
OBJECTIVES To describe the primary phenotypic characteristics and differences between
type I and type II Usher syndrome and to establish a phenotype-genotype correlation for the
2 most frequent mutations in the USH2A gene.
DESIGN, SETTING, AND PARTICIPANTS Cross-sectional study at a genetics department, in
which clinical evaluations were performed for 433 patients (297 unrelated families) who were
classified as having type I, II, III, atypical, or unclassified Usher syndrome according to their
clinical history, pedigree data, results from ophthalmological studies, and audiological,
neurophysiological, and vestibular test results. Molecular studies were performed for 304
patients (256 unrelated families). The Mann-Whitney U test or the χ2 test was used for
calculating the differences between mean values for the analyzed parameters.
MAIN OUTCOMES AND MEASURES Age at diagnosis; age at onset of night blindness, visual field
loss, visual acuity loss, and cataracts; and severity and age at diagnosis of hearing loss.
RESULTS The comparison between patients with type I Usher syndrome and those with type
II Usher syndrome revealed P < .001 for most items analyzed. The most frequent mutations in
the USH2A gene were the p.Glu767Serfs*21 and p.Cys759Phe mutations, with an allelic
frequency of 23.2%(63 of 272 alleles) and 8.1% (22 of 272 alleles), respectively. The
phenotypic analysis for patients carrying p.Cys759Phe showed P < .001 for most items
analyzed when compared with patients carrying p.Glu767Serfs*21 and when compared with
patients carrying other mutations in the USH2A gene. None of the p.Cys759Phe patients
exhibited a severe hearing loss phenotype, and more than 60%had only mild hearing loss.
Most patients carrying the p.Glu767Serfs*21 mutation (72.1%) were moderately deaf.
CONCLUSIONS AND RELEVANCE Our study presents the clinical differences between type I and
type II Usher syndrome and between the 2 most frequent mutations in the USH2A gene.
Detailed genotype-phenotype correlations, as presented in our study, allow for a better
correlation of clinical signs with a known genotype and can improve the clinical management,
genetic counseling, and risk assessment of patients with Usher syndrome because an
estimated prognosis of their disease can be madeThis work was supported by
grant PI13/00226 (to Servicio de Genética, Instituto
de Investigación–Fundación Jiménez Díaz, Madrid,
Spain), by grant PI13/00638 (to Unidad de
Genética y Diagnóstico Prenatal, Hospital
Universitario y Politécnico La Fe, Valencia, Spain),
and by grant 06/07/0036 (to Centro de
Investigación Biomédica en Red de Enfermedades
Raras, Madrid, Spain) from Fundaluce and
Organización Nacional de Ciegos Españole
Genotype–phenotype correlation in patients with Usher syndrome and pathogenic variants in MYO7A: implications for future clinical trials
Purpose: We aimed to establish correlations between the clinical features of a cohort of Usher syndrome (USH) patients with pathogenic variants in MYO7A, type of pathogenic variant, and location on the protein domain. Methods: Sixty-two USH patients from 46 families with biallelic variants in MYO7A were examined for visual and audiological features. Participants were evaluated based on self-reported ophthalmological history and ophthalmological investigations (computerized visual field testing, best-corrected visual acuity, and ophthalmoscopic and electrophysiological examination). Optical coherence tomography and fundus autofluorescence imaging were performed when possible. Auditory and vestibular functions were evaluated. Patients were classified according to the type of variant and the protein domain where the variants were located. Results: Most patients displayed a typical USH1 phenotype, that is, prelingual severe-profound sensorineural hearing loss, prepubertal retinitis pigmentosa (RP) and vestibular dysfunction. No statistically significant differences were observed for the variables analysed except for the onset of hearing loss due to the existence of two USH2 cases, defined as postlingual sensorineural hearing loss, postpubertal onset of RP, and absence of vestibular dysfunction, and one atypical case of USH. Conclusion: We were unable to find a correlation between genotype and phenotype for MYO7A. However, our findings could prove useful for the assessment of efficacy in clinical trials, since the type of MYO7A variant does not seem to change the onset, severity or course of visual disease.This project was financially supported by the Center for Biomedical Network Research on Rare Diseases (CIBERER), FIS (PI16/00425, PI16/00539 and IIS‐FJD Biobank PT13/0010/0012). LG‐M and IPR were supported by the Río Hortega and predoctoral Programs (CM16/00126 and FI17/00192, respectively) from Institute of Health Carlos III (ISCIII, Spanish Ministry of the Economy, Industry and Competitiveness), Regional Government of Madrid (CAM, B2017/BMD37), and Regional Government of the Valencian Community (PROMETEU/2018/135), with partial support from the European Regional Development Fund (ERDF). Additional support was received from the Ramon Areces Foundation, the University Chair UAM‐IIS‐FJD of Genomic Medicine, ONCE Foundation and the Spanish National Organization of the Blind (ONCE). Drafting of this manuscript was possible thanks to the UshTher project (Clinical trial of gene therapy with dual AAV vectors for retinitis pigmentosa in patients with Usher syndrome type IB), which has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 754848. The authors are grateful to the families that participated in this study and to the colleagues who referred patients to us. We also thank the Genetics and Ophthalmology Departments of Fundación Jimenez Diaz University Hospital (FJD, Madrid) and Asunción Giménez, Cristina Villaverde, and Ignacio Mahillo for their technical assistance
Nonuniqueness of best rational Chebyshev approximations on the unit disk
AbstractIn the past it has been unknown whether complex rational best Chebyshev approximations (BAs) on the unit disk need be unique. This paper answers this and related questions by exhibiting examples in which: (a) the BA is not unique, (b) the number of distinct BAs is arbitrarily large, (c) the BA to a real analytic function f (i.e., f(z) = f(z)) among rational functions with real coefficients is not unique, and (d) the complex BAs to such a function are better than any approximation with real coefficients. Except in case (d), our constructions hold for approximation of arbitrary type (m, n) with n ⩾ 1. Finally, by the same methods we also establish the new result that if a function is approximated on a small disk about 0 of radius ε (or on an interval of length ε), then as ε → 0, the BA need not in general approach the corresponding Padé approximant in a sense considered by J. L. Walsh
A nonsynonymous FCER1B SNP is associated with risk of developing allergic rhinitis and with IgE levels
Allergic rhinitis is associated with elevated serum IgE levels. IgE response is mediated by the highaffinity IgE receptor (FcεRI), which is polymorphic. Studies analyzing the association between allergic rhinitis and FcεRI variants have been conducted with controversial results. The objective of this study is to analyze, in 1,041 individuals, the putative clinical association of allergic rhinitis with common polymorphisms in FcεRI subunits genes. These SNPs included FECR1A rs2494262, rs2427837 and rs2251746; FECR1B rs1441586, rs569108 and rs512555; FCER1G rs11587213, rs2070901 and rs11421. Statistically significant differences were observed for the FCER1B rs569108 and rs512555 polymorphisms frequencies when comparing patients with allergic rhinitis without asthma and controls. The OR (95% CI) value for the 237Gly allele (rs569108) is equal to 0.26 (0.08–0.86, P = 0.017) and for the G allele (rs512555) it is equal to 0.27 (0.08–0.88, P = 0.020). These two SNPs are linked (D’ = 1.0, LOD = 56.05). Also observed was a statistically significant trend towards lower IgE values among allergic rhinitis patients with variant alleles for both SNPs. In conclusion, in patients with allergic rhinitis without asthma, the FCER1B rs569108 and rs512555 polymorphisms are associated with increased risk of developing allergic rhinitis and with lower IgE levels.Trabajo financiado por:
Instituto de Salud Carlos III. Fondo de Investigación Sanitaria. Becas PI12/00241, PI12/00324 y RETICS RD12/0013/0002
Junta de Extremadura y Fondos FEDER. Ayuda GR15026peerReviewe
Measurement invariance of the day reconstruction method: Results from the COURAGE in Europe Project
The final publication is available at Springer via http://dx.doi.org/10.1007/s10902-015-9669-xGiven the growing interest in the study of subjective well-being as a measure of social progress, instruments that produce valid and reliable scores and that can be used within and across countries are needed. The aim of the present study was to analyze the measurement equivalence of the Day Reconstruction Method in its brief version, using nationally representative samples from Finland, Poland, and Spain obtained within the COURAGE in Europe project. The goodness-of-fit of a two-correlated-factors model and the reliability of the scores obtained were assessed. Cross-country invariance was tested employing a multiple group confirmatory factor analysis, through sequential constraint imposition. In each country, measurement invariance was tested across time frames (morning, afternoon and evening) and days of the week (weekday and weekend). The results found support for the hypothesis of a two-correlated-factors (positive and negative affect) structure; the reliability of the positive, the negative and the net affect scores showed appropriate values. A high equivalence across the three national samples was found: all items except one showed strong measurement invariance indicating that respondents from Finland, Poland, and Spain attribute the same meaning to the latent construct under study, and the levels of the underlying items are equal in all three countries. Similar results were found for the measurement equivalence across time frames and days of the week. Our findings support the assumption of comparability across the different samples considered; in general, higher positive affect and lower negative affect were found in Finland, in the evening and at the weekendThe research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement number 223071 (COURAGE in Europe), from the Instituto de Salud Carlos III-FIS research grants number PS09/00295 and PS09/01845, and from the Spanish Ministry of Science and Innovation ACI-Promociona (ACI2009-1010). The study was supported by the Instituto de Salud Carlos III, Centro de Investigación Biomédica Red de Salud Mental (CIBERSAM), and the AGES-CM Programme (AGES-S2010/BMD-2422), B.O. is grateful to the Sara Borrell postdoctoral programme (reference no. CD12/00429) supported by the Instituto de Salud Carlos III, Spain
Relationship among Streptococcus gallolyticus Subsp. gallolyticus, Enterococcus faecalis and Colorectal Neoplasms in Recurrent Endocarditis: A Historical Case Series.
Objectives: The role of colorectal neoplasms (CRN) as a common potential source of recurrent Streptococcus gallolyticus subsp. gallolyticus (SGG) and Enterococcus faecalis (EF) endocarditis remains unstudied. We aimed to investigate what proportion of episodes of recurrent endocarditis are caused by a succession of SGG and EF, or vice versa, and to assess the role of a colonic source in such recurrent episodes. Methods: we conducted a retrospective analysis of two prospective endocarditis cohorts (1979-2019) from two Spanish hospitals, providing descriptive analyses of the major features of the endocarditis episodes, colonoscopy findings, and histologic results. Results: among 1552 IE episodes, 204 (13.1%) were caused by EF and 197 (12.7%) by SGG, respectively. There were 155 episodes (10%) of recurrent IE, 20 of which (12.9%) were due to a succession of SGG/EF IE in 10 patients (the first episode caused by SGG in eight cases, and by EF in two cases). The median follow-up was 86 (interquartile range 34-156) months. In 8/10 initial episodes, the causative microorganism was SGG, and all patients were diagnosed with CRN either during the initial episode or during follow-up. During the second episode of IE or follow-up, colonoscopies revealed CRN in six patients. Conclusions: There seems to be an association between SGG and EF in recurrent endocarditis that warrants further investigation. Our findings reinforce the need for systematically performing colonoscopy in the event of endocarditis caused by both microorganisms
Whole-exome sequencing reveals ZNF408 as a new gene associated with autosomal recessive retinitis pigmentosa with vitreal alterations
Retinitis pigmentosa (RP) is a group of progressive inherited retinal dystrophies that cause visual impairment as a result of photoreceptor cell death. RP is heterogeneous, both clinically and genetically making difficult to establish precise genotype–phenotype correlations. In a Spanish family with autosomal recessive RP (arRP), homozygosity mapping and whole-exome sequencing led to the identification of a homozygous mutation (c.358_359delGT; p.Ala122Leufs*2) in the ZNF408 gene. A screening performed in 217 additional unrelated families revealed another homozygous mutation (c.1621C>T; p.Arg541Cys) in an isolated RP case. ZNF408 encodes a transcription factor that harbors 10 predicted C2H2-type fingers thought to be implicated in DNA binding. To elucidate the ZNF408 role in the retina and the pathogenesis of these mutations we have performed different functional studies. By immunohistochemical analysis in healthy human retina, we identified that ZNF408 is expressed in both cone and rod photoreceptors, in a specific type of amacrine and ganglion cells, and in retinal blood vessels. ZNF408 revealed a cytoplasmic localization and a nuclear distribution in areas corresponding with the euchromatin fraction. Immunolocalization studies showed a partial mislocalization of the p.Arg541Cys mutant protein retaining part of the WT protein in the cytoplasm. Our study demonstrates that ZNF408, previously associated with Familial Exudative Vitreoretinopathy (FEVR), is a new gene causing arRP with vitreous condensations supporting the evidence that this protein plays additional functions into the human retina.This work is supported by CIBERER (06/07/0036), FIS (PI013/00226), Ministry of Economy and Competitiveness-FEDER (BFU2012-36845), RETICS (RD12/0034/0010), Fundación ONCE, Fundaluce and grants BIO2011-27069 from the Spanish Ministry of Economy and Competitiveness, and PROMETEOII/2014/025 from the Conselleria de Educacio of the Valencia Community. PC is supported by Fundación Conchita Rábago (FCR), MC by Miguel Servet ISCIII (CP/03256) and dS by CAPES Foundation, Ministry of Education of Brazil
CPAMD8 loss-of-function underlies non-dominant congenital glaucoma with variable anterior segment dysgenesis and abnormal extracellular matrix
Abnormal development of the ocular anterior segment may lead to a spectrum of clinical phenotypes ranging from primary congenital glaucoma (PCG) to variable anterior segment dysgenesis (ASD). The main objective of this study was to identify the genetic alterations underlying recessive congenital glaucoma with ASD (CG-ASD). Next-generation DNA sequencing identified rare biallelic CPAMD8 variants in four patients with CG-ASD and in one case with PCG. CPAMD8 is a gene of unknown function and recently associated with ASD. Bioinformatic and in vitro functional evaluation of the variants using quantitative reverse transcription PCR and minigene analysis supported a loss-of-function pathogenic mechanism. Optical and electron microscopy of the trabeculectomy specimen from one of the CG-ASD cases revealed an abnormal anterior chamber angle, with altered extracellular matrix, and apoptotic trabecular meshwork cells. The CPAMD8 protein was immunodetected in adult human ocular fluids and anterior segment tissues involved in glaucoma and ASD (i.e., aqueous humor, non-pigmented ciliary epithelium, and iris muscles), as well as in periocular mesenchyme-like cells of zebrafish embryos. CRISPR/Cas9 disruption of this gene in F0 zebrafish embryos (96 hpf) resulted in varying degrees of gross developmental abnormalities, including microphthalmia, pharyngeal maldevelopment, and pericardial and periocular edemas. Optical and electron microscopy examination of these embryos showed iridocorneal angle hypoplasia (characterized by altered iris stroma cells, reduced anterior chamber, and collagen disorganized corneal stroma extracellular matrix), recapitulating some patients’ features. Our data support the notion that CPAMD8 loss-of-function underlies a spectrum of recessive CG-ASD phenotypes associated with extracellular matrix disorganization and provide new insights into the normal and disease roles of this gene
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