18 research outputs found

    Screening of esophageal varices by esophageal capsule endoscopy: results of a French multicenter prospective study

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    BACKGROUND AND STUDY AIM: Esophageal video capsule endoscopy (ECE) is a new technique that allows examination of the esophagus using a noninvasive approach. The aim of this study was to compare ECE with esophagogastroduodenoscopy (EGD) for the diagnosis of esophageal varices in patients with cirrhosis. PATIENTS AND METHODS: A total of 330 patients with cirrhosis and with no known esophageal varices were prospectively enrolled. Patients underwent ECE first, followed by EGD (gold standard). The endoscopists who performed EGD were blind to the ECE result. Patient satisfaction was assessed using a visual analog scale (maximum score 100). RESULTS: A total of 30 patients were excluded from the analysis because they did not undergo any endoscopic examinations. Patients (mean age 56 years; 216 male) had mainly alcoholic (45 %) or viral (27 %) cirrhosis. The diagnostic indices of ECE to diagnose and correctly stage esophageal varices were: sensitivity 76 % and 64 %, specificity 91 % and 93 %, positive predictive value 88 % and 88 %, and negative predictive value 81 % and 78 %, respectively. ECE patient satisfaction scored significantly higher than EGD (87 ± 22 vs. 58 ± 35; P < 0.0001). CONCLUSIONS: ECE was well tolerated and safe in patients with liver cirrhosis and suspicion of portal hypertension. The sensitivity of ECE is not currently sufficient to replace EGD as a first exploration in these patients. However, due to its excellent specificity and positive predictive value, ECE may have a role in cases of refusal or contraindication to EGD. ECE might also improve compliance to endoscopic follow-up and aid important therapeutic decision making in the prophylaxis of bleeding. TRIAL REGISTRATION: EudraCT (ID RCB 2009-A00532-55) and ClinicalTrials.gov (NCT00941421)

    A structural model of a P450-ferredoxin complex from orientation-selective double electron-electron resonance spectroscopy

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    This research was supported by the Engineering & Physical Sciences Research Council (EPSRC) and the Biotechnology & Biological Sciences Research Council (BBSRC), UK (EP/D048559). AMB and EOJD were supported by graduate studentships from the BBSRC (BB/F01709X/1) and NJH and JEL were supported by graduate studentships from the EPSRC, and JEL after her DPhil by EP/D048559. AMB gratefully acknowledges her current fellowship support from the Royal Society and EPSRC for a Dorothy Hodgkin Fellowship (DH160004). JRH acknowledges support from the ARC (FT120100421) and the Centre for Advanced Imaging, The University of Queensland.Cytochrome P450 (CYP) monooxygenases catalyze the oxidation of chemically inert carbon-hydrogen bonds in diverse endogenous and exogenous organic compounds by atmospheric oxygen. This C–H bond oxy-functionalization activity has huge potential in biotechnological applications. Class I CYPs receive the two electrons required for oxygen activation from NAD(P)H via a ferredoxin reductase and ferredoxin. The interaction of Class I CYPs with their cognate ferredoxin is specific. In order to reconstitute the activity of diverse CYPs, structural characterization of CYP-ferredoxin complexes is necessary, but little structural information is available. Here we report a structural model of such a complex (CYP199A2-HaPux) in frozen solution derived from distance and orientation restraints gathered by the EPR technique of orientation-selective double electron-electron resonance (os-DEER). The long-lived oscillations in the os-DEER spectra were well modeled by a single orientation of the CYP199A2-HaPux complex. The structure is different from the two known Class I CYP-Fdx structures: CYP11A1-Adx and CYP101A1-Pdx. At the protein interface, HaPux residues in the [Fe2S2] cluster-binding loop and the α3 helix, and the C-terminus residue interact with CYP199A2 residues in the proximal loop and the C helix. These residue contacts are consistent with biochemical data on CYP199A2-ferredoxin binding and electron transfer. Electron-tunneling calculations indicate an efficient electron-transfer pathway from the [Fe2S2] cluster to the heme. This new structural model of a CYP-Fdx complex provides the basis for tailoring CYP enzymes for which the cognate ferredoxin is not known, to accept electrons from HaPux and display monooxygenase activity.PostprintPeer reviewe

    Human papillomavirus does not play a role in the Barrett esophagus: a French cohort

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    International audienceThe role of human papillomavirus (HPV) in Barrett's esophagus (BE) has been examined but remains unclear. The purpose of the study is to dispute the connection between HPV and BE in a prospective case-control study. Biopsies were performed above and inside the Barrett's segment for BE patients and in the distal third of the esophagus for control patients for histological interpretation and for virological analysis. Biopsies for virological analysis were placed in a virus transport medium and immediately frozen in liquid nitrogen. Virological analysis involved real-time PCR using the SyBr® green protocol with modified SPF10 general primers. A total of 180 patients (119 control and 61 BE, respectively) were included. In BE patients, 31, 18, and 12 patients had, respectively, no dysplasia, low-grade dysplasia, and high grade dysplasia. Overall, nine were found to be HPV positive: five were control patients and four BE patients. HPV positive status was not associated with BE. No factors were associated with HPV, in particular the degree of BE dysplasia. HPV infection appears unlikely to be significant in the etiology of BE compared with control patients. (ClinicalTrials.gov, Number NCT02549053)

    A structural model of a P450-ferredoxin complex from orientation-selective double electron-electron resonance spectroscopy

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    Cytochrome P450 (CYP) monooxygenases catalyze the oxidation of chemically inert carbon-hydrogen bonds in diverse endogenous and exogenous organic compounds by atmospheric oxygen. This C–H bond oxy-functionalization activity has huge potential in biotechnological applications. Class I CYPs receive the two electrons required for oxygen activation from NAD(P)H via a ferredoxin reductase and ferredoxin. The interaction of Class I CYPs with their cognate ferredoxin is specific. In order to reconstitute the activity of diverse CYPs, structural characterization of CYP-ferredoxin complexes is necessary, but little structural information is available. Here we report a structural model of such a complex (CYP199A2-HaPux) in frozen solution derived from distance and orientation restraints gathered by the EPR technique of orientation-selective double electron-electron resonance (os-DEER). The long-lived oscillations in the os-DEER spectra were well modeled by a single orientation of the CYP199A2-HaPux complex. The structure is different from the two known Class I CYP-Fdx structures: CYP11A1-Adx and CYP101A1-Pdx. At the protein interface, HaPux residues in the [Fe2S2] cluster-binding loop and the α3 helix, and the C-terminus residue interact with CYP199A2 residues in the proximal loop and the C helix. These residue contacts are consistent with biochemical data on CYP199A2-ferredoxin binding and electron transfer. Electron-tunneling calculations indicate an efficient electron-transfer pathway from the [Fe2S2] cluster to the heme. This new structural model of a CYP-Fdx complex provides the basis for tailoring CYP enzymes for which the cognate ferredoxin is not known, to accept electrons from HaPux and display monooxygenase activity
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