24 research outputs found

    Opérateur-réseau et approche relationnelle : l'industrie du fret aérien au Canada

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    Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

    Clinical reappraisal of SHORT syndrome with PIK3R1 mutations: towards recommendation for molecular testing and management

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    International audienceSHORT syndrome has historically been defined by its acronym: short stature (S), hyperextensibility of joints and/or inguinal hernia (H), ocular depression (O), Rieger abnormality (R) and teething delay (T). More recently several research groups have identified PIK3R1 mutations as responsible for SHORT syndrome. Knowledge of the molecular etiology of SHORT syndrome has permitted a reassessment of the clinical phenotype. The detailed phenotypes of 32 individuals with SHORT syndrome and PIK3R1 mutation, including eight newly ascertained individuals, were studied to fully define the syndrome and the indications for PIK3R1 testing. The major features described in the SHORT acronym were not universally seen and only half (52%) had 4 or more of the classic features. The commonly observed clinical features of SHORT syndrome seen in the cohort included IUGR \textless 10(th) percentile, postnatal growth restriction, lipoatrophy and the characteristic facial gestalt. Anterior chamber defects and insulin resistance or diabetes were also observed but were not as prevalent. The less specific, or minor features of SHORT syndrome include teething delay, thin wrinkled skin, speech delay, sensorineural deafness, hyperextensibility of joints and inguinal hernia. Given the high risk of diabetes mellitus, regular monitoring of glucose metabolism is warranted. An echocardiogram, ophthalmological and hearing assessments are also recommended

    Cyclodextrin Polymer Nanoassemblies: Strategies for Stability Improvement

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    International audienceThe main goal of this work was to develop two strategies for stabilization of nanoassemblies made of beta-cyclodextrin polymer and amphiphilic dextran associated through host-guest complexes. The first strategy was to coat the nanoassemblies with a dextran derivative bearing adamantyl anchoring groups and hydrophilic poly(ethylene oxide-co-propylene oxide) side chains to increase the steric repulsion between the nanoassemblies. The second strategy developed was to post-reticulate the nanoassemblies upon UV irradiation. Photo-cross-linkable nanoassemblies have been prepared from new host or guest polymers bearing allylether or methacrylate groups. The modified nanoassemblies have been characterized by dynamic light scattering as a function of time and for various salt and competitor concentrations The results of the first strategy show an improvement of shelf stability and resistance at relatively low concentrations of competitors. The second strategy is the most efficient in providing good shelf stability, much larger than with the first strategy, together with a large resistance to dissociation in presence of competitors

    Cyclodextrin Polymer Nanoassemblies: Strategies for Stability Improvement

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    The main goal of this work was to develop two strategies for stabilization of nanoassemblies made of β-cyclodextrin polymer and amphiphilic dextran associated through host–guest complexes. The first strategy was to coat the nanoassemblies with a dextran derivative bearing adamantyl anchoring groups and hydrophilic poly­(ethylene oxide-<i>co</i>-propylene oxide) side chains to increase the steric repulsion between the nanoassemblies. The second strategy developed was to post-reticulate the nanoassemblies upon UV irradiation. Photo-cross-linkable nanoassemblies have been prepared from new host or guest polymers bearing allylether or methacrylate groups. The modified nanoassemblies have been characterized by dynamic light scattering as a function of time and for various salt and competitor concentrations. The results of the first strategy show an improvement of shelf stability and resistance at relatively low concentrations of competitors. The second strategy is the most efficient in providing good shelf stability, much larger than with the first strategy, together with a large resistance to dissociation in presence of competitors

    Tipranavir-Ritonavir Genotypic Resistance Score in Protease Inhibitor-Experienced Patients▿

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    To identify mutations associated with the virological response (VR) to a tipranavir-ritonavir (TPV/r)-based regimen, 143 patients previously treated with protease inhibitor (PI) were studied. VR was defined by a decrease of at least 1 log10 in, or undetectable, human immunodeficiency virus (HIV) RNA at month 3. The effect of each mutation in the protease, considering all variants at a residue as a single variable, on the VR to TPV/r was investigated. Mutations at six residues were associated with a lower VR (E35D/G/K/N, M36I/L/V, Q58E, Q61D/E/G/H/N/R, H69I/K/N/Q/R/Y, and L89I/M/R/T/V), and one mutation was associated with a higher VR (F53L/W/Y). The genotypic score M36I/L/V − F53L/W/Y + Q58E + H69I/K/N/Q/R/Y + L89I/M/R/T/V was selected as providing a strong association with VR. For the seven patients with a genotypic score of −1 (viruses with only mutation at codon 53), the percentage of responders was 100% and the percentages were 79%, 56%, 33%, 21%, and 0% for those with scores of 0, 1, 2, 3, and 4, respectively. The percentage of patients showing a response to TPV/r was lower for patients infected with non-clade B viruses (n = 16, all non-B subtypes considered together) than for those infected with clade B viruses (n = 127) (25% and 59%, respectively; P = 0.015). Most mutations associated with VR to TPV/r had not previously been associated with PI resistance. This is consistent with phenotypic analysis showing that TPV has a unique resistance profile. Mutations at five positions (35, 36, 61, 69, and 89) were observed significantly more frequently in patients infected with a non-B subtype than in those infected with the B subtype, probably explaining the lower VR observed in these patients

    PIK3R1 Mutations Cause Syndromic Insulin Resistance with Lipoatrophy

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    International audienceShort stature, hyperextensibility of joints and/or inguinal hernia, ocular depression, Rieger anomaly, and teething delay (SHORT) syndrome is a developmental disorder with an unknown genetic cause and hallmarks that include insulin resistance and lack of subcutaneous fat. We ascertained two unrelated individuals with SHORT syndrome, hypothesized that the observed phenotype was most likely due to de novo mutations in the same gene, and performed whole-exome sequencing in the two probands and their unaffected parents. We then confirmed our initial observations in four other subjects with SHORT syndrome from three families, as well as 14 unrelated subjects presenting with syndromic insulin resistance and/or generalized lipoatrophy associated with dysmorphic features and growth retardation. Overall, we identified in nine affected individuals from eight families de novo or inherited PIK3R1 mutations, including a mutational hotspot (c.1945C>T [p.Arg649Trp]) present in four families. PIK3R1 encodes the p85 alpha, p55 alpha, and p50 alpha regulatory subunits of class IA phosphatidylinositol 3 kinases (PI3Ks), which are known to play a key role in insulin signaling. Functional data from fibroblasts derived from individuals with PIK3R1 mutations showed severe insulin resistance for both proximal and distal PI3K-dependent signaling. Our findings extend the genetic causes of severe insulin-resistance syndromes and provide important information with respect to the function of PIK3R1 in normal development and its role in human diseases, including growth delay, Rieger anomaly and other ocular affections, insulin resistance, diabetes, paucity of fat, and ovarian cysts
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