Influence of omeprazol on the antiplatelet action of clopidogrel associated to aspirin.
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Aged↗
Biomedical subjects
B Arnaud
Publications and source records attributed to B Arnaud.
Huge excitonic effects in layered hexagonal boron nitride.
The all-electron GW approximation energy band gap of bulk hexagonal boron nitride is shown to be of indirect type. The resulting computed in-plane polarized optical spectrum, obtained by solving the Bethe-Salpeter equation for the electron-hole two-particle Green function, is in excellent agreement with experiment and has a strong anisotropy compared to out-of-plane polarized spectrum. A detailed analysis of the excitonic structures within the band gap shows that the low-lying excitons belong to the Frenkel class and are tightly confined within the layers. The calculated exciton binding energy is much larger than that obtained by Watanabe et al. [Nat. Mater. 3, 404 (2004).] based on a Wannier model assuming h-BN to be a direct-band-gap semiconductor.
Journal Article↗
[Accuracy of videokeratographic quantitative criteria for detection of keratoconus suspects in families with keratoconus].
AIM: We statistically assessed the videokeratographic data obtained from families with keratoconus in order to determine reliable criteria for detecting keratoconus suspects. MATERIAL AND METHODS: Fourteen keratoconus patients from 12 families were enlisted. We investigated 55 relatives (110 eyes). Standard videokeratographic data were obtained by screening 30 individuals (60 eyes) with clinically normal eyes, with no history of ocular disorders, contact lens wear, or keratoconus individuals in their family. Videokeratographic qualitative and quantitative analyses were performed on every subject. The videokeratographic threshold values obtained from the control group were used as a reference. RESULTS: Two criteria based on the Klyce/Maeda indices proved their statistical significance in detecting keratoconus suspects. When considering the significant criteria ascertained by the statistical analysis, building pedigrees favored the autosomal dominant mode of inheritance. Two of the pedigrees corresponded to either a recessive mode of transmission or the potential occurrence of a de novo mutation. CONCLUSION: We have determined videokeratographic criteria of statistical significance for detecting keratoconus suspects. The knowledge of the status of each member of families with keratoconus is a prerequisite to performing genetic linkage analyses, which may allow a precise locus linked with this disorder to be refined.
Adolescent↗
[Amiodarone and disk edema: physiopathological debate based on a case report].
We describe the case of a patient showing bilateral disk edema linked to amiodarone intake and discuss the controversial physiopathology of this condition. The clinical investigation as well as the follow-up of this case established the diagnosis of amiodarone-induced papillary disease. Pseudotumor cerebri and alteration of optic disk vascularization were also involved in the optic neuropathy displayed by this patient. This case illustrates the multifactorial character of this entity whose heterogeneous clinical expression is linked both to the direct toxic effect of amiodarone and the likely occurrence of pseudotumor cerebri, as well as to the disorders for which this type of medication is frequently used. Amiodarone is widely used and its implication as a cause of disk swelling should be systematically investigated.
Aged↗
[Optic nerve sheath decompression in optic neuropathy complicating idiopathic intracranial hypertension: a new focus].
Optic nerve sheath decompression is a surgical procedure only used in optic neuropathy complicating idiopathic intracranial hypertension. We describe this technique and compare it with the classic technique of cerebrospinal liquid derivation. Several points contrast optic nerve sheath decompression and cerebrospinal fluid derivation: there is no biomaterial, it is limited to the orbital area, and intracranial pressure remains unchanged. The complications are different, yet analysis of the literature shows the same efficacy in terms of visual function. We recommend a practical management of optic neuropathy complicating idiopathic intracranial hypertension, depending on the functional severity and the therapeutic efficacy. The surgical indication should only concern serious optic neuropathy not responding to medical therapy, with the choice of the surgical technique belonging to the surgeon.
Decompression, Surgical↗
[Clinically isolated Morning glory syndrome].
The Morning glory syndrome is an uncommon congenital optic disk anomaly. It is characterized by a funnel-shaped and enlarged dysplasic optic disk with white tissue, and retinal vessels arising from the periphery of the disk and running an abnormally straight course over the peripapillary retina. We report here the case of a 7-year-old girl with a delayed diagnosis of Morning glory syndrome discovered at a regular examination that showed amblyopia. The optic disk anomaly was isolated. The search for other associated morphological and/or functional abnormalities is mandatory (retinal and/or cerebral malformation, frontonasal dysplasia, endocrine irregularities, neurofibromatosis type 2). Periodic ophthalmological examinations are recommended due to the frequency of retinal detachment.
Amblyopia↗
[Spontaneous hyphema caused by Ginkgo biloba extract].
We report the first case of a patient in whom Ginkgo biloba extract proved to be the unique cause of spontaneous hyphema. Extensive ophthalmological and biological investigations were undertaken in order to assess the role of Ginkgo biloba: platelet numbering, hemostasis factors, Willebrand antigen, ristocetin cofactor, platelet glycoprotein immunophenotyping, glycoprotein expression after activation by thrombin, inflammatory markers, B-scan ultrasonography, and fluorescent iridography. No putative causes of hyphema were recorded other than Gingko biloba intake. The bleeding originated from the 12-o'clock position of the iris margin. Anamnesis identified Ginkgo biloba extract ingestion from 2 weeks before the appearance of the patient's visual trouble. Ginkgo biloba intake was stopped and the hemorrhage resolved with no recurrence during the 18 months of follow-up. Ginkgo biloba is known for platelet inhibition and is extensively used in the elderly because of its beneficial effects as a vascular protector. The clinical progression of the present case strongly suggests that Ginkgo biloba may cause hemorrhage and hyphema, even in the absence of any other predisposing factor.
Aged↗
Segregation of a mutation in CNGB1 encoding the beta-subunit of the rod cGMP-gated channel in a family with autosomal recessive retinitis pigmentosa.
Retinitis pigmentosa (RP) is a clinically and genetically heterogeneous group of retinal diseases leading to blindness. By performing full genome linkage analysis in a consanguineous French family affected with severe autosomal recessive RP, we have excluded linkage to known loci involved in RP and mapped a novel locus to chromosome 16q13-q21 (Zmax=2.83 at theta=0 at the D16S3089 locus). Two candidate genes KIFC3 and CNGB1 mapping to this critical interval have been screened for mutations. The CNGB1 gene, which encodes the beta-subunit of the rod cGMP-gated channel, is mutated in the family presented in this study.
Amino Acid Sequence↗
Retinal dystrophies caused by mutations in RPE65: assessment of visual functions.
AIMS: To characterise the disease in patients with mutations in RPE65. METHODS: Individuals from two families were studied clinically. RESULTS: 13 and 20 year old compound heterozygote individuals from one family with R234X and 1121delA mutations showed nystagmus, macular dystrophy and low contrasted spots in the fundus. Some heterozygotes had macular drusen. A 40 year old compound heterozygote individual from another family with L22P and H68Y mutations had few bone spicule pigment deposits and macular atrophy. CONCLUSION: Compound heterozygote individuals had severe rod-cone dystrophies featuring few pigment deposits in the fundus, pigment epithelium atrophy, and early involvement of the macula, with variations in severity leading to the diagnosis of Leber's congenital amaurosis or retinitis pigmentosa. Macular drusen in heterozygotes carrying a null allele may reflect the decreased capacity in the RPE65 function.
Adolescent↗
In vitro creation of amyloid fibrils from native and Arg124Cys mutated betaIGH3((110-131)) peptides, and its relevance for lattice corneal amyloid dystrophy type I.
BetaIGH3 protein has been recently involved in the pathogenesis of blinding corneal diseases, some of which have characteristic amyloid corneal deposits. The 124 codon of the betaig-h3 gene seems to be crucial for the amyloidogenicity of the protein product. We presently report an in vitro system that reproducibly forms amyloid fibrils from betaIGH3((110-131)) derived peptides. We also assessed the differences in fibril formation of two 22-amino acid peptides centered on the 124 residue: the native form and the Arg124Cys peptide (mutation linked to lattice corneal amyloid dystrophy type 1). After dialysis of Arg124Cys peptide against PBS 1/15 M pH 7.4 for 72 hours, Congo red staining and electron microscopy demonstrated the presence of abundant material fulfilling the criteria of amyloid. Quantitative analysis with thioflavine T fluorescence studies confirmed the high capacity of Arg124Cys peptide to form amyloid fibrils when compared to the native form.
Amino Acid Sequence↗
W179R: a novel missense mutation in the peripherin/RDS gene in a family with autosomal dominant retinitis pigmentosa.
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Arginine↗
Keratographic analysis of a family with keratoconus in identical twins.
We screened family members of monozygotic twins with keratoconus to search for a corneal thinning disorder using clinical, videokeratographic, and pachymetric analyses. The parents had bilateral astigmatism of a symmetric bow-tie pattern with normal videokeratographic and pachymetric indices. The 8-year-old sister had slightly asymmetric astigmatism in both eyes with normal pachymetry values. No family member was suspected of a corneal thinning disorder. We discuss the mode of inheritance of keratoconus in this family.
Adolescent↗
Nuclear gene OPA1, encoding a mitochondrial dynamin-related protein, is mutated in dominant optic atrophy.
Optic atrophy type 1 (OPA1, MIM 165500) is a dominantly inherited optic neuropathy occurring in 1 in 50,000 individuals that features progressive loss in visual acuity leading, in many cases, to legal blindness. Phenotypic variations and loss of retinal ganglion cells, as found in Leber hereditary optic neuropathy (LHON), have suggested possible mitochondrial impairment. The OPA1 gene has been localized to 3q28-q29 (refs 13-19). We describe here a nuclear gene, OPA1, that maps within the candidate region and encodes a dynamin-related protein localized to mitochondria. We found four different OPA1 mutations, including frameshift and missense mutations, to segregate with the disease, demonstrating a role for mitochondria in retinal ganglion cell pathophysiology.
Amino Acid Sequence↗
A syndrome combining severe hypotrichosis and macular dystrophy: absence of mutations in TIMP genes.
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Adult↗
BIGH3 exon 14 mutations lead to intermediate type I/IIIA of lattice corneal dystrophies.
PURPOSE: To screen the BIGH3 gene in three unrelated families with lattice corneal dystrophy (LCD), two of which disclosed a particular phenotype. METHODS: Genomic DNA was extracted from peripheral leukocytes of the affected patients and their family members. The entire coding sequence of the BIGH3 gene was screened for mutations by means of transcript analysis on total RNA isolated from peripheral leukocytes by reverse transcription-polymerase chain reaction performed with primers designed for this study. Each mutation was confirmed at the genomic level, by using published primers. RESULTS: One family that had a typical form of LCD, had the described R124C mutation in the BIGH3 gene. Two families with atypical forms of LCD were negative for the previously known mutations of the gene. Direct sequencing of the BIGH3 mRNA in the latter two families allowed us to identify two mutations located in exon 14. They consist of a 9-bp insertion at position 18851886 and one missense mutation at position 1877 of the BIGH3 gene. Three new polymorphisms were also observed. CONCLUSIONS: Two mutations different from those linked to LCD have been found in clinically distinguishable forms of this disease, intermediate between LCDs types I and IIIA. The DNA segment comprising both alterations normally encodes for a highly conserved region of the fourth internal domain of the Betaig-h3 protein, suggesting that this region may be of functional and/or structural importance. The identification of new mutations by screening of the complete BIGH3 gene and the comparative analysis of the induced modifications in betaig-h3 protein should shed light in the understanding of the molecular mechanisms underlying LCDs resulting from mutations in the BIGH3 gene, and may help to explain their phenotypic heterogeneity.
Adult↗
[Molecular genetics of pigmentary retinopathies: identification of mutations in CHM, RDS, RHO, RPE65, USH2A and XLRS1 genes].
PURPOSE: To evaluate the occurrence and inheritance of various types of pigmentary retinopathy in patients followed at the outpatient clinic in the university hospital, Montpellier, France. To characterize genes and mutations causing these conditions. METHODS: Ophthalmic examination and various visual tests were performed. Mutations were sought from genomic DNA by PCR amplification of exons associated with single-strand conformation analysis and/or direct sequencing. RESULTS: Among 315 patients over an 8-year period, cases of retinitis pigmentosa (63.2%), Usher's syndrome (10.2%), Stargardt's disease (5.4%), choroideremia (3.2%), Leber's congenital amaurosis (3.2%), congenital stationary night blindness (2.9%), cone dystrophy (2.5%), dominant optic atrophy (1.9%), X-linked juvenile retinoschisis (1.6%), Best's disease (1.6%), and others (4.3%) were diagnosed. In retinitis pigmentosa, inheritance could be determined in 54.2% of the cases including dominant autosomic (26.6%), recessive autosomic (22.6%), and X-linked cases (5%) while it could not be confirmed in 45.7% of the cases (simplex cases in the majority). For the 6 examined genes, mutations were found in 22 out of 182 propositus (12.1%). Analysis of phenotype-genotype correlations indicates that in retinitis pigmentosa, RDS is more frequently associated with macular involvement and retinal flecks, RHO with regional disease, and RPE65 with the great severity of the disease with some cases of Leber's congenital amaurosis. CONCLUSIONS: Identification of genes may help in diagnosis and in genetic counseling, especially in simplex cases with retinitis pigmentosa. In this latter condition, molecular diagnosis will be necessary to rationalize future treatments.
Adaptor Proteins, Signal Transducing↗
[Ocular toxocariasis. Value of local immunodiagnosis].
Toxocara canis is a nematode that may be involved in human ocular toxocariasis. Specific immunotesting is of importance but may be negative as toxocara antigens may localize exclusively in vitreous humor. We report here the case of one patient with optic disc toxocariasis granuloma negative for toxocara canis immunodiagnostic on serum. Clinical diagnosis was confirmed by toxocara canis specific enzyme-linked immunosorbent assay (ELISA) on aqueous humor showing elevated titers of antibodies. Systemic steroids associated to specific treatment of toxocariasis were initiated. Follow-up displayed regression of uveitis but development of vitreous bands leading to posterior retinal detachment. Toxocara posterior granuloma is of poor visual prognosis. Moreover, diagnosis may be of late setting, as clinical features are often unrecognized and specific immunodiagnostic on serum negative. Specific immunotesting on aqueous humor is of particular importance to rule out severe clinical differential diagnosis such as retinoblastoma in children. Ultrasound biomicroscopy (UBM) seems to be specific and sensitive in patients with a presumed diagnosis of peripheral toxocariasis. Granuloma surgery appears to yield good clinical results and allows histological confirmation of the diagnosis.
Adult↗