540 research outputs found

    N Engl J Med

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    CC999999/Intramural CDC HHS/United States2015-12-07T00:00:00Z23190229PMC467119

    Clin Pharmacol Ther

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    As evidence accumulates on the use of genomic tests and other health-related applications of genomic technologies, decision makers may increasingly seek support in identifying which applications have sufficiently robust evidence to suggest they might be considered for action. As an interim working process to provide such support, we developed a horizon-scanning method that assigns genomic applications to tiers defined by availability of synthesized evidence. We illustrate an application of the method to pharmacogenomics tests.CC999999/Intramural CDC HHS/United States2015-12-23T00:00:00Z24398597PMC468913

    Native Ion Mobility Mass Spectrometry: When Gas-Phase Ion Structures Depend on the Electrospray Charging Process

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    International audienceIon mobility spectrometry (IMS) has become popular to characterize biomolecule folding. Numerous studies have shown that proteins that are folded in solution remain folded in the gas phase, whereas proteins that are unfolded in solution adopt more extended conformations in the gas phase. Here, we discuss how general this tenet is. We studied single-stranded DNAs (human telomeric cytosine-rich sequences with CCCTAA repeats), which fold into an intercalated motif (i-motif) structure in a pH-dependent manner, thanks to the formation of C-H +-C base pairs. As i-motif formation is favored at low ionic strength, we could investigate the ESI-IMS-MS behavior of i-motif structures at pH ~5.5 over a wide range of ammonium acetate concentrations (15 mM to 100 mM). The control experiments consisted of either the same sequence at pH ~7.5, wherein the sequence is unfolded, or sequence variants that cannot form i-motifs (CTCTAA repeats). The surprising results came from the control experiments. We found that the ionic strength of the solution had a greater effect on the compactness of the gas-phase structures than the solution folding state. This means that electrosprayed ions keep a memory of the charging process, which is influenced by the electrolyte concentration. We discuss these results in light of the analyte partitioning between the droplet interior and droplet surface, which in turn influences the probability of being ionized via a charged residue-type pathway or a chain extrusion-type pathway.La spectrométrie de mobilité ionique (IMS) est devenue populaire pour caractériser le pliage des biomolécules. De nombreuses études ont montré que les protéines repliées en solution restent repliées en phase gazeuse, alors que les protéines dépliées en solution adoptent des conformations plus étendues en phase gazeuse. Ici, nous discutons du caractère général de ce principe. Nous avons étudié les ADN simple brins (séquences télomériques humaines riches en cytosine avec répétitions CCCTAA), qui se replient en une structure de motif intercalé (i-motif) d'une manière dépendant du pH, grâce à la formation de paires de bases C-H +-C. Comme la formation de motifs i-motifs est favorisée à faible force ionique, nous avons pu étudier le comportement des structures i-motifs ESI-IMS-MS à pH ~5,5 sur une large gamme de concentrations en acétate d'ammonium (15 mM à 100 mM). Les expériences de contrôle consistent soit en la même séquence à pH ~7,5 (à ce pH la séquence est dépliée), soit en des variantes de séquence qui ne peuvent pas former d'i-motifs (répétitions CTCTAA). Les résultats surprenants proviennent des expériences de contrôle. Nous avons constaté que la force ionique de la solution avait un effet plus important sur la compacité des structures en phase gazeuse que l'état de repliement de la solution. Cela signifie que les ions produits par électrospray gardent une mémoire du processus d'acquisition de la charge, et que celui-ci est influencé par la concentration de l'électrolyte. Nous discutons de ces résultats à la lumière de la répartition de l'analyte entre l'intérieur des gouttelettes et la surface des gouttelettes, réaprtition qui à son tour influence la probabilité pour la molécule d'être ionisée par une voie de type résidu chargé ou par une voie d'extrusion de la chaîne

    Tumor Necrosis Factor Alpha Antagonists and Occurrence of Autoantibodies in Inflammatory Bowel Disease Patients: A Single Center Experience

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    Background & Aims: Appearance of auto antibodies have been described during anti-tumor necrosis factor (TNF) alpha therapy; however, their prevalence and clinical relevance are still unclear. We investigated prevalence of autoantibodies in inflammatory bowel diseases (IBD) patients on anti-TNFα treatment and occurrence of clinical symptoms. Methods: Titers of ANA, anti-dsDNA, SMA, AMA, LKM were evaluated from blood samples in patients receiving anti-TNFα inhibitor (adalimumab, infliximab). Results: Among 39 patients treated with anti-TNFα therapy, twenty of them developed ANA, mostly induced by infliximab. 55% ANA positive patients developed peripheral polyarthralgias with no need for intervention. No patients with positive autoantibodies developed a drug-induced lupus. The incidence of dsDNA, SMA and AMA was low and was not associated with autoimmune disease. Conclusions: Immune response induced by anti-TNFα is restricted to ANA, with lower prevalence of dsDNA antibodies, SMA and AMA. Further studies are needed to clarify the role of autoantibodies during anti-TNFα therapy

    Thrombin–aptamer recognition: a revealed ambiguity

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    Aptamers are structured oligonucleotides that recognize molecular targets and can function as direct protein inhibitors. The best-known example is the thrombin-binding aptamer, TBA, a single-stranded 15-mer DNA that inhibits the activity of thrombin, the key enzyme of coagulation cascade. TBA folds as a G-quadruplex structure, as proved by its NMR structure. The X-ray structure of the complex between TBA and human α-thrombin was solved at 2.9-Å resolution, but did not provide details of the aptamer conformation and the interactions with the protein molecule. TBA is rapidly processed by nucleases. To improve the properties of TBA, a number of modified analogs have been produced. In particular, a modified TBA containing a 5′-5′ polarity inversion site, mTBA, has higher stability and higher affinity toward thrombin with respect to TBA, although it has a lower inhibitory activity. We present the crystal structure of the thrombin–mTBA complex at 2.15-Å resolution; the resulting model eventually provides a clear picture of thrombin–aptamers interaction, and also highlights the structural bases of the different properties of TBA and mTBA. Our findings open the way for a rational design of modified aptamers with improved potency as anticoagulant drugs

    Liver function test abnormalities in patients with inflammatory bowel diseases: A hospital-based survey

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    BACKGROUND AND AIMS: Inflammatory bowel diseases (IBD) are frequently associated with altered liver function tests (LFTs). The causal relationship between abnormal LFTs and IBD is unclear. The aim of our study was to evaluate the prevalence and etiology of LFTs abnormalities and their association with clinical variables in a cohort of IBD patients followed up in a single center. MATERIALS AND METHODS: A retrospective review was undertaken of all consecutive IBD in-and outpatients routinely followed up at a single referral center. Clinical and demographic parameters were recorded. Subjects were excluded if they had a previous diagnosis of chronic liver disease. LFT abnormality was defined as an increase in aspartate aminotransferase, (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), gammaglutamyl transpeptidase (GGT), or total bilirubin. RESULTS: A cohort of 335 patients (179 males, mean age 46.0±15.6 years) was analyzed. Abnormal LFTs were detected in 70 patients (20.9%). In most cases, the alterations were mild and spontaneously returned to normal values in about 60% of patients. Patients with abnormal LFTs were less frequently on treatment with aminosalicylates (22.8 vs. 36.6%, P=0.04). The most frequent cause for transient abnormal LFTs was drug-induced cholestasis (34.1%), whereas fatty liver was the most frequent cause of persistent liver damage (65.4%). A cholestatic pattern was found in 60.0% of patients and was mainly related to older age, longer duration of disease, and hypertension. CONCLUSIONS: The prevalence of LFT abnormalities is relatively high in IBD patients, but the development of severe liver injury is exceptional. Moreover, most alterations of LFTs are mild and spontaneously return to normal values. Drug-induced hepatotoxicity and fatty liver are the most relevant causes of abnormal LFTs in patients with IB

    High pressure treatment and green tea extract synergistically control enteric virus contamination in beverages

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    Consumers are driving food production toward the use of natural preservatives and minimal processing technologies. Green tea extract (GTE) at low concentration could be combined with high pressure processing (HPP) for reduced treatment times and quality impact on foods in a hurdle concept for synergistic effects on foodborne viral pathogens, specifically human norovirus and hepatitis A virus (HAV). Viral inactivation by HPP (at 300, 400, and 500 MPa for 5 min) combined with 3.3 mg/mL aged-GTE was initially evaluated in buffer (PBS) against murine norovirus (MNV), a culturable human norovirus surrogate, and HAV. Furthermore, human norovirus inactivation was evaluated by the novel human intestinal enteroid system (HIE) and a capsid integrity binding assay (ISC-RT-qPCR). HPP treatment completely inhibits human norovirus GII.4 infectivity when applied at 500 MPa alone and at 400 MPa combined with aged-GTE. Additional experiments investigated the reduction of MNV and HAV infectivity in apple and horchata juices exposed to combined aged-GTE and HPP treatments. Results demonstrated that the addition of aged-GTE to the juices exposed to HPP significantly inactivated MNV and HAV at reduced holding pressure time. This synergistic effect of aged-GTE combined with HPP treatments represents a hurdle technology that could be exploited as a control measure to improve the food safety of beverages

    Molecular basis of phospholipase A2 inhibition by petrosaspongiolide M.

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    Petrosaspongiolide M (PM) is an anti-inflammatory marine metabolite that displays a potent inhibitory activity toward group II and III secretory phospholipase A2 (PLA2) enzymes. The details of the mechanism, which leads to a covalent adduct between PLA2 and γ-hydroxybutenolide-containing molecules such as PM, are still a matter of debate. In this paper the covalent binding of PM to bee venom PLA2 has been investigated by mass spectrometry and molecular modeling. The mass increment observed for the PM-PLA2 adduct is consistent with the formation of a Schiff base by reaction of a PLA2 amino group with the hemiacetal function (masked aldehyde) at the C-25 atom of the PM γ-hydroxybutenolide ring. Proteolysis of the modified PLA2 by the endoprotease LysC followed by HPLC MS analysis allowed us to establish that the PLA2 α-amino terminal group of the lle-1 residue was the only covalent binding site for PM. The stoichiometry of the reaction between PM and PLA2 was also monitored and results showed that even with excess inhibitor, the prevalent product is a 1:1 (inhibitor:enzyme) adduct, although a 2:1 adduct is present as a minor component. The 2:1 adduct was also characterized, which showed that the second site of reaction is located at the ε-amino group of the Lys-85 residue. Similar results in terms of the reaction profile, mass increments, and location of the PLA2 binding site were obtained for manoalide, a paradigm for irreversible PLA2 inhibitors, which suggests that the present results may be considered of more general interest within the field of anti-inflammatory sesterterpenes that contain the γ-hydroxybutenolide pharmacophore. Finally, a 3D model, constrained by the above experimental results, was obtained by docking the inhibitor molecule into the PLA2 binding site through AFFINITY calculations. The model provides an interesting insight into the PM-PLA2 inhibition process and may prove useful in the design of new anti-inflammatory agents that target PLA2 secretory enzymes

    Jaminaea phylloscopi sp. Nov. (microstromatales), a basidiomycetous yeast isolated from migratory birds in the mediterranean basin

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    During a survey of yeasts vectored by migratory birds in the Mediterranean basin, isolations from the cloacae of members of the order Passeriformes collected in Ustica (Italy) were performed. Based on phylogenetic analysis of the D1/D2 domain of the 26S rRNA gene and the internal transcribed spacer ITS1-5.8S rRNA gene-ITS2 region, five yeast isolates clustered in a new lineage within the Microstromatales clade. The DNA sequences of these isolates differed from those of their closest relatives, Jaminaea angkorensis and Jaminaea lanaiensis, by 20 and 25 nt substitutions in the D1/D2 domain and 119 and 131 nt substitutions in the complete ITS region, respectively. In addition, the five isolates showed phenotypic characteristics not observed in their closest relatives, such as the ability to grow at 44 °C and at pH 2.5, which suggests a possible adaptation to the bird gastrointestinal tract. On the basis of the isolation source, phenotypic features and molecular strain typing carried out with randomly amplified polymorphic DNA (RAPD)-PCR and mini-satellite-primed (MSP)-PCR analysis, the five isolates were characterized as five distinct strains of a novel species formally described as Jaminaea phylloscopi sp. nov., with 551B6T (=PYCC 6783T=CBS 14087T) as the type strain. The Mycobank accession number is MB811984
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