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Ali Deeb A, Settmacher U, Fritsch J, Dondorf F, Rohland O, Rauchfuß F. Sarcopenic obesity may predict worse liver regeneration after right graft living donor liver transplantation. Liver Transpl 2024; 30:412-420. [PMID: 37548548 DOI: 10.1097/lvt.0000000000000238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 07/31/2023] [Indexed: 08/08/2023]
Abstract
Sarcopenic obesity impairs the outcome after liver transplantation. The effect of this on liver regeneration has not yet been studied. The aim of this study was to evaluate the potential effect of body composition changes on liver volume gain after living donor liver transplantation. We observed liver regeneration in 100 patients who underwent living donor liver transplantation using right lobe grafts (Segments V-VIII). Liver volumetry and body composition analysis were performed based on CT images with special software. The gain of liver volume was calculated between 2 points in time considering the absolute and percentage values: before surgery and early after surgery, with a median time of 10 days. Pearson's correlation and multivariate analysis using stepwise multiple regression were used to examine the potential correlation between body composition and liver volume gain. The liver volume increase was significantly negatively correlated with adipose tissue in the body stem ( r = -0.4, p < 0.001) and positively correlated with psoas mass ( r = 0.24, p = 0.02). These results correspond with those of the multiple regression analysis, which indicated adipose tissue (ß = -1.0, p < 0.001) and psoas mass (ß = 0.12, p < 0.001). The presence of malignancy as an indication for liver transplantation was another significant independent factor negatively affecting liver growth (ß = -13.1, p = 0.046). Sarcopenic obesity predicts an impaired liver volume increase after living donation. This could worsen the postoperative outcome. The role of alimentary interventions and exercises in improving body composition and thus postoperative outcome should be evaluated through prospective interventional studies.
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Affiliation(s)
- Aladdin Ali Deeb
- Department of General, Visceral and Vascular Surgery, Jena University Hospital, Jena, Germany
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Rath A, Kieninger B, Fritsch J, Caplunik-Pratsch A, Blaas S, Ochmann M, Pfeifer M, Hartl J, Holzmann T, Schneider-Brachert W. Whole-genome sequencing reveals two prolonged simultaneous outbreaks involving Pseudomonas aeruginosa high-risk strains ST111 and ST235 with resistance to quaternary ammonium compounds. J Hosp Infect 2024; 145:155-164. [PMID: 38286239 DOI: 10.1016/j.jhin.2024.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/09/2024] [Accepted: 01/15/2024] [Indexed: 01/31/2024]
Abstract
OBJECTIVE Water-bearing systems are known as frequent Pseudomonas aeruginosa (PA) outbreak sources. However, many older buildings continue to have sanitary facilities in high-risk departments such as the ICU. We present two simultaneous prolonged multi-drug-resistant (MDR) PA outbreaks detected at the ICU of a pulmonology hospital, which were resolved by whole-genome sequencing (WGS). METHODS Outbreak management and investigations were initiated in August 2019 after detecting two patients with nosocomial VIM-2-positive MDR PA. The investigations involved weekly patient screenings for four months and extensive environmental sampling for 15 months. All patient and environmental isolates were collected and analysed by WGS. RESULTS From April to September 2019, we identified 10 patients with nosocomial MDR PA, including five VIM-2-positive strains. VIM-2-positive strains were also detected in nine sink drains, two toilets, and a cleaning bucket. WGS revealed that of 16 VIM-2-positive isolates, 14 were ST111 that carried qacE, or qacEΔ1 genes, whereas 13 isolates clustered (difference of ≤11 alleles by cgMLST). OXA-2 (two toilets), and OXA-2, OXA-74, PER-1 (two patients, three toilets) qacEΔ1-positive ST235 isolates dominated among VIM-2-negative isolates. The remaining seven PA strains were ST17, ST233, ST273, ST309 and ST446. Outbreak containment was achieved by replacing U-bends, and cleaning buckets, and switching from quaternary ammonium compounds (QUATs) to oxygen-releasing disinfectant products. CONCLUSION Comprehension and management of two simultaneous MDR PA outbreaks involving the high-risk strains ST111 and ST235 were facilitated by precise control due to identification of different outbreak sources per strain, and by the in-silico detection of high-level QUATs resistance in all isolates.
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Affiliation(s)
- A Rath
- Department of Infection Prevention and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany.
| | - B Kieninger
- Department of Infection Prevention and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany
| | - J Fritsch
- Department of Infection Prevention and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany
| | - A Caplunik-Pratsch
- Department of Infection Prevention and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany
| | - S Blaas
- Donaustauf Hospital, Centre for Pneumology, Donaustauf, Germany
| | - M Ochmann
- Donaustauf Hospital, Centre for Pneumology, Donaustauf, Germany
| | - M Pfeifer
- Donaustauf Hospital, Centre for Pneumology, Donaustauf, Germany; Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany; Hospital of the Merciful Brother Regensburg, Regensburg, Germany
| | - J Hartl
- Department of Infection Prevention and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany; Hospital of the Merciful Brother "St. Barbara", Schwandorf, Germany
| | - T Holzmann
- Department of Infection Prevention and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany
| | - W Schneider-Brachert
- Department of Infection Prevention and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany
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Rath A, Kieninger B, Caplunik-Pratsch A, Fritsch J, Mirzaliyeva N, Holzmann T, Bender JK, Werner G, Schneider-Brachert W. Concerning emergence of a new vancomycin-resistant Enterococcus faecium strain ST1299/CT1903/vanA at a tertiary university centre in South Germany. J Hosp Infect 2024; 143:25-32. [PMID: 37852539 DOI: 10.1016/j.jhin.2023.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/22/2023] [Accepted: 10/08/2023] [Indexed: 10/20/2023]
Abstract
BACKGROUND vanB-carrying vancomycin-resistant Enterococcus faecium (VREfm) of the sequence types 80 (ST80) and ST117 have dominated Germany in the past. In 2020, our hospital witnessed a sharp increase in the proportion of vanA-positive VREfm. AIM To attempt to understand these dynamics through whole-genome sequencing (WGS) and analysis of nosocomial transmissions. METHODS At our hospital, the first VREfm isolate per patient, treated during 2020, was analysed retrospectively using specific vanA/vanB PCR, WGS, multi-locus sequence typing (MLST), and core-genome (cg) MLST. Epidemiologic links between VRE-positive patients were assessed using hospital occupancy data. FINDINGS Isolates from 319 out of 356 VREfm patients were available for WGS, of which 181 (56.7%) fulfilled the ECDC definition for nosocomial transmission. The high load of nosocomial cases is reflected in the overall high clonality rate with only three dominating sequence (ST) and complex types (CT), respectively: the new emerging strain ST1299 (100% vanA, 77.4% CT1903), and the well-known ST80 (90.0% vanB, 81.0% CT1065) and ST117 (78.0% vanB, 65.0% CT71). The ST1299 isolates overall, and the subtype CT1903 in particular, showed high isolate clonality, which demonstrates impressively high spreading potential. Overall, 152 out of 319 isolates had an allelic cgMLST difference of ≤3 to another, including 91 (59.6%) ST1299. Occupancy data identified shared rooms (3.7%), shared departments (6.2%), and VRE-colonized prior room occupants (0.6%) within 30 days before diagnosis as solid epidemiological links. CONCLUSION A new emerging VREfm clone, ST1299/CT1903/vanA, dominated our institution in 2020 and has been an important driver of the increasing VREfm rates.
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Affiliation(s)
- A Rath
- Department of Infection Prevention and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany.
| | - B Kieninger
- Department of Infection Prevention and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany
| | - A Caplunik-Pratsch
- Department of Infection Prevention and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany
| | - J Fritsch
- Department of Infection Prevention and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany
| | - N Mirzaliyeva
- Department of Infection Prevention and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany
| | - T Holzmann
- Department of Infection Prevention and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany
| | - J K Bender
- Department of Infectious Diseases, Division of Nosocomial Pathogens and Antibiotic Resistances, Robert Koch Institute, Wernigerode, Germany
| | - G Werner
- Department of Infectious Diseases, Division of Nosocomial Pathogens and Antibiotic Resistances, Robert Koch Institute, Wernigerode, Germany
| | - W Schneider-Brachert
- Department of Infection Prevention and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany
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Schmidt A, Kalms J, Lorent C, Katz S, Frielingsdorf S, Evans RM, Fritsch J, Siebert E, Teutloff C, Armstrong FA, Zebger I, Lenz O, Scheerer P. Stepwise conversion of the Cys 6[4Fe-3S] to a Cys 4[4Fe-4S] cluster and its impact on the oxygen tolerance of [NiFe]-hydrogenase. Chem Sci 2023; 14:11105-11120. [PMID: 37860641 PMCID: PMC10583674 DOI: 10.1039/d3sc03739h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 09/20/2023] [Indexed: 10/21/2023] Open
Abstract
The membrane-bound [NiFe]-hydrogenase of Cupriavidus necator is a rare example of a truly O2-tolerant hydrogenase. It catalyzes the oxidation of H2 into 2e- and 2H+ in the presence of high O2 concentrations. This characteristic trait is intimately linked to the unique Cys6[4Fe-3S] cluster located in the proximal position to the catalytic center and coordinated by six cysteine residues. Two of these cysteines play an essential role in redox-dependent cluster plasticity, which bestows the cofactor with the capacity to mediate two redox transitions at physiological potentials. Here, we investigated the individual roles of the two additional cysteines by replacing them individually as well as simultaneously with glycine. The crystal structures of the corresponding MBH variants revealed the presence of Cys5[4Fe-4S] or Cys4[4Fe-4S] clusters of different architecture. The protein X-ray crystallography results were correlated with accompanying biochemical, spectroscopic and electrochemical data. The exchanges resulted in a diminished O2 tolerance of all MBH variants, which was attributed to the fact that the modified proximal clusters mediated only one redox transition. The previously proposed O2 protection mechanism that detoxifies O2 to H2O using four protons and four electrons supplied by the cofactor infrastructure, is extended by our results, which suggest efficient shutdown of enzyme function by formation of a hydroxy ligand in the active site that protects the enzyme from O2 binding under electron-deficient conditions.
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Affiliation(s)
- Andrea Schmidt
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics (CC2), Group Structural Biology of Cellular Signaling Charitéplatz 1 10117 Berlin Germany
| | - Jacqueline Kalms
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics (CC2), Group Structural Biology of Cellular Signaling Charitéplatz 1 10117 Berlin Germany
| | - Christian Lorent
- Institut für Chemie, Biophysical Chemistry, Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
| | - Sagie Katz
- Institut für Chemie, Biophysical Chemistry, Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
| | - Stefan Frielingsdorf
- Institut für Chemie, Biophysical Chemistry, Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
| | | | - Johannes Fritsch
- Institut für Chemie, Biophysical Chemistry, Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
| | - Elisabeth Siebert
- Institut für Chemie, Biophysical Chemistry, Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
| | - Christian Teutloff
- Department of Physics, Freie Universität Berlin Arnimallee 14 14195 Berlin Germany
| | | | - Ingo Zebger
- Institut für Chemie, Biophysical Chemistry, Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
| | - Oliver Lenz
- Institut für Chemie, Biophysical Chemistry, Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
| | - Patrick Scheerer
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics (CC2), Group Structural Biology of Cellular Signaling Charitéplatz 1 10117 Berlin Germany
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Fritsch J, Settmacher U, Ali Deeb A. [34/f-Heartburn and nocturnal cough : Preparation for the medical specialist examination: part 36]. Chirurgie (Heidelb) 2023; 94:39-42. [PMID: 37347288 DOI: 10.1007/s00104-023-01912-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/24/2023] [Indexed: 06/23/2023]
Affiliation(s)
- Johannes Fritsch
- Klinik für Allgemein‑, Viszeral- und Gefäßchirurgie, Universitätsklinikum Jena, Am Klinikum1, 07747, Jena, Deutschland
| | - Utz Settmacher
- Klinik für Allgemein‑, Viszeral- und Gefäßchirurgie, Universitätsklinikum Jena, Am Klinikum1, 07747, Jena, Deutschland
| | - Aladdin Ali Deeb
- Klinik für Allgemein‑, Viszeral- und Gefäßchirurgie, Universitätsklinikum Jena, Am Klinikum1, 07747, Jena, Deutschland.
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Ali Deeb A, Settmacher U, Fritsch J, Dondorf F, Rohland O, Rauchfuß F. Postoperative Outcomes in 415 Patients Following Liver Transplantation Using Extended Donor Criteria: A Study from a Single Center in Germany. Ann Transplant 2023; 28:e939060. [PMID: 37025050 PMCID: PMC10088457 DOI: 10.12659/aot.939060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023] Open
Abstract
BACKGROUND Because of the massive organ shortage worldwide, marginal organs are increasingly being considered. The aim of this study was to present a comprehensive analysis of donor-related factors clinically supposed to influence the outcome after liver transplantation. This study from a single center in Germany aimed to evaluate postoperative outcomes in 415 patients following liver transplantation using extended donor criteria. MATERIAL AND METHODS Extended donor criteria (EDC) were considered according to the official guidelines issued through the German Medical Association. Other factors and the Eurotransplant Donor Risk Index (ET-DRI) were also considered. Correlation studies, logistic regression, and Kaplan-Meier-estimator were used to evaluate the outcome. RESULTS The postoperative outcomes with or without EDC were comparable. Other factors had an impact on early allograft failure (EAD), including male donors (χ²=14.135, P=0.0001). Other donor-unrelated factors, like cold ischemia time, also had an impact on EAD (r=0.135, P=0.010), especially in patients with model for end-stage liver disease (MELD) <25 (ß=0.001, P=0.008). ET-DRI was a crucial factor in estimating overall and allograft survival after liver transplantation. CONCLUSIONS The findings from this study support the possibility of liver transplantation using organs obtained by EDC. Other factors, like donor sex and cold ischemic time, are not part of the EDC, although they have an impact on EAD. Organs obtained by EDC continue to be an option to address the organ shortage.
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Affiliation(s)
- Aladdin Ali Deeb
- Department of General, Visceral and Vascular Surgery, Jena University Hospital, Jena, Germany
| | - Utz Settmacher
- Department of General, Visceral and Vascular Surgery, Jena University Hospital, Jena, Germany
| | - Johannes Fritsch
- Department of General, Visceral and Vascular Surgery, Jena University Hospital, Jena, Germany
| | - Felix Dondorf
- Department of General, Visceral and Vascular Surgery, Jena University Hospital, Jena, Germany
| | - Oliver Rohland
- Department of General, Visceral and Vascular Surgery, Jena University Hospital, Jena, Germany
| | - Falk Rauchfuß
- Department of General, Visceral and Vascular Surgery, Jena University Hospital, Jena, Germany
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Fritsch J, Ardelt M, Settmacher U. [Recurrence-free survival versus overall survival as a primary endpoint after resection of colorectal liver metastases]. Chirurgie (Heidelb) 2023; 94:272-273. [PMID: 36745200 DOI: 10.1007/s00104-023-01837-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Affiliation(s)
| | - M Ardelt
- Klinik für Allgemein‑, Viszeral‑ und Gefäßchirurgie, Universitätsklinikum Jena, Am Klinikum 1, 07747, Jena, Deutschland.
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Fritsch J, Ardelt M, Settmacher U. [Prediction of 10-year survival after colorectal liver metastases based on patient, tumor and treatment characteristics]. Chirurgie (Heidelb) 2022; 93:1103-1104. [PMID: 36205753 DOI: 10.1007/s00104-022-01746-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Affiliation(s)
- J Fritsch
- Klinik für Allgemein‑, Viszeral- und Gefäßchirurgie, Am Klinikum 1, 07747, Jena, Deutschland
| | - M Ardelt
- Klinik für Allgemein‑, Viszeral- und Gefäßchirurgie, Am Klinikum 1, 07747, Jena, Deutschland.
| | - U Settmacher
- Klinik für Allgemein‑, Viszeral- und Gefäßchirurgie, Am Klinikum 1, 07747, Jena, Deutschland
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Heck AL, Mishra S, Prenzel T, Feulner L, Achhammer E, Särchen V, Blagg BSJ, Schneider-Brachert W, Schütze S, Fritsch J. Selective HSP90β inhibition results in TNF and TRAIL mediated HIF1α degradation. Immunobiology 2021; 226:152070. [PMID: 33639524 DOI: 10.1016/j.imbio.2021.152070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/23/2020] [Accepted: 01/31/2021] [Indexed: 12/17/2022]
Abstract
Signaling via TNF-R1 mediates pleiotropic biological outcomes ranging from inflammation and proliferation to cell death. Previous reports demonstrated that pro-survival signaling emanates from membrane resident TNF-R1 complexes (complex I) while only internalized TNF-R1 complexes are capable for DISC formation (complex II) and thus, apoptosis induction. Internalized TNF-R1 containing endosomes undergo intracellular maturation towards lysosomes, resulting in activation and release of Cathepsin D (CtsD) into the cytoplasm. We recently revealed HSP90 as target for proteolytic cleavage by CtsD, resulting in cell death amplification. In this study, we show that extrinsic cell death activation via TNF or TRAIL results in HSP90β degradation. Co-incubation of cells with either TNF or TRAIL in combination with the HSP90β inhibitor KUNB105 but not HSP90α selective inhibition promotes apoptosis induction. In an attempt to reveal further downstream targets of combined TNF-R1 or TRAIL-R1/-R2 activation with HSP90β inhibition, we identify HIF1α and validate its ligand:inhibitor triggered degradation. Together, these findings suggest that selective inhibition of HSP90 isoforms together with death ligand stimulation may provide novel strategies for therapy of inflammatory diseases or cancer, in future.
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Affiliation(s)
- A L Heck
- Institute of Immunology, Christian-Albrechts-University of Kiel, 24105 Kiel, Germany
| | - S Mishra
- Department of Chemistry and Biochemistry, The University of Notre Dame, Notre Dame, IN 46556, United States
| | - T Prenzel
- Department of Infection Prevention and Infectious Diseases, University of Regensburg, 93053 Regensburg, Germany
| | - L Feulner
- Department of Infection Prevention and Infectious Diseases, University of Regensburg, 93053 Regensburg, Germany
| | - E Achhammer
- Department of Infection Prevention and Infectious Diseases, University of Regensburg, 93053 Regensburg, Germany
| | - V Särchen
- Institute of Immunology, Christian-Albrechts-University of Kiel, 24105 Kiel, Germany
| | - B S J Blagg
- Department of Chemistry and Biochemistry, The University of Notre Dame, Notre Dame, IN 46556, United States
| | - W Schneider-Brachert
- Department of Infection Prevention and Infectious Diseases, University of Regensburg, 93053 Regensburg, Germany
| | - S Schütze
- Institute of Immunology, Christian-Albrechts-University of Kiel, 24105 Kiel, Germany
| | - J Fritsch
- Institute of Immunology, Christian-Albrechts-University of Kiel, 24105 Kiel, Germany; Department of Infection Prevention and Infectious Diseases, University of Regensburg, 93053 Regensburg, Germany.
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Fritsch J, Ardelt M, Settmacher U. [Liver transplantation after tumor downstaging in hepatocellular carcinoma]. Chirurg 2020; 91:891. [PMID: 32930818 DOI: 10.1007/s00104-020-01282-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
| | - Michael Ardelt
- Klinik für Allgemein‑, Viszeral- und Gefäßchirurgie, Am Klinikum 1, 07747, Jena, Deutschland.
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Abstract
ZusammenfassungDie kardiorespiratorische Fitness gilt als unabhängiger Prognosefaktor für Morbidität und Mortalität unterschiedlicher Genese. Patientenrelevante Symptome wie latente Belastungsdyspnoe, körperliche Leistungsdefizite und Erschöpfung korrelieren oft schlecht mit der kardiopulmonalen und bildgebenden „Ruhediagnostik“. Die Spiroergometrie als Goldstandard der Belastungsanalyse dient der Früherkennung, Differenzialdiagnostik, Verlaufs- und Therapiekontrolle von kardiopulmonalen Erkrankungen und deren Prognose. Als integrative Untersuchungsmethode des Lungen-Herz-Kreislauf-Muskel-Systems ist sie bei geringem zeitlichem Mehraufwand deutlich aussagekräftiger und informativer als alternative Messmethoden und ermöglicht auch Aussagen im submaximalen Belastungsbereich. Trotz dieser enormen Bedeutung wird die Spiroergometrie aus verschiedenen Gründen (z. B. Aufwand, Budget, Expertise) auch hierzulande zu selten durchgeführt. Die Methode ist komplex, aber nicht unbedingt kompliziert. Ziel dieser Übersicht ist es daher, allen Interessierten diesen häufig wegweisenden Globaltest leichter zugänglich zu machen. Inhaltlich werden sowohl die physiologischen Grundlagen, die Indikationen und praktischen Aspekte der Messung als auch die strukturierte Auswertung spiroergometrischer Befunde übersichtlich vorgestellt. Damit soll auch das Interesse und der eigene Anspruch geweckt werden, diese fachspezifische Referenzuntersuchung in indizierten Fällen selbst häufiger durchzuführen.
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Affiliation(s)
- T. Glaab
- Medizinische Klinik III, Abteilung Pneumologie, Universitätsmedizin Mainz, Mainz
- Pneumologische Gemeinschaftspraxis, Koblenz
| | - O. Schmidt
- Pneumologische Gemeinschaftspraxis, Koblenz
| | - J. Fritsch
- Facharztzentrum am Heilig-Geist-Gesundheitszentrum, Kardiologische Gemeinschaftspraxis, Köln
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Bissinger T, Fritsch J, Mihut A, Wu Y, Liu X, Genzel Y, Tan WS, Reichl U. Semi-perfusion cultures of suspension MDCK cells enable high cell concentrations and efficient influenza A virus production. Vaccine 2019; 37:7003-7010. [DOI: 10.1016/j.vaccine.2019.04.054] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 04/10/2019] [Accepted: 04/18/2019] [Indexed: 12/13/2022]
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Fritsch J. [Ethics committees in security-relevant research according to the recommendations of Leopoldina and the German Research Foundation]. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2019; 62:744-750. [PMID: 31069418 DOI: 10.1007/s00103-019-02954-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The scientific freedom protected by the German Basic Law is a prerequisite for the progress and prosperity of society. However, free research is also associated with risks resulting from the fact that useful research results and methods can be abused, for example as weapons of war or as a means of criminal or terrorist activities.According to the German National Academy of Sciences Leopoldina and the German Research Foundation (DFG), meaningful control of these risks cannot be achieved through further legislation but only through appropriate awareness raising and self-governance tools within the scientific community. In order to make this more concrete, both organizations jointly published the "Recommendations for Handling Security-Relevant Research" in 2014. For the effective and sustainable implementation of these recommendations, the DFG and Leopoldina established the Joint Committee on the Handling Security-Relevant Research.In Germany, there are already numerous commissions with different names that deal with ethical issues in science. For some years now, in addition to the most numerous medical ethics committees primarily responsible for medical research on human beings and those committees supporting the authorities in deciding on the approval of animal experiments to protect animal welfare, an increasing number of so-called committees for ethics in security-relevant research have been set up. Following the recommendations of the joint committee of the DFG and Leopoldina, these committees advise researchers on site on questions concerning security-relevant aspects of research.
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Affiliation(s)
- Johannes Fritsch
- Gemeinsamer Ausschuss zum Umgang mit sicherheitsrelevanter Forschung, Nationale Akademie der Wissenschaften Leopoldina, c/o ABC Business Center, Friedrichstr. 79, 10117, Berlin, Deutschland.
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Hartmann S, Frielingsdorf S, Ciaccafava A, Lorent C, Fritsch J, Siebert E, Priebe J, Haumann M, Zebger I, Lenz O. O2-Tolerant H2 Activation by an Isolated Large Subunit of a [NiFe] Hydrogenase. Biochemistry 2018; 57:5339-5349. [DOI: 10.1021/acs.biochem.8b00760] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sven Hartmann
- Department of Chemistry, Sekr. PC14, Technische Universität Berlin, 10623 Berlin, Germany
| | - Stefan Frielingsdorf
- Department of Chemistry, Sekr. PC14, Technische Universität Berlin, 10623 Berlin, Germany
| | - Alexandre Ciaccafava
- Department of Chemistry, Sekr. PC14, Technische Universität Berlin, 10623 Berlin, Germany
| | - Christian Lorent
- Department of Chemistry, Sekr. PC14, Technische Universität Berlin, 10623 Berlin, Germany
| | - Johannes Fritsch
- Department of Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
| | - Elisabeth Siebert
- Department of Chemistry, Sekr. PC14, Technische Universität Berlin, 10623 Berlin, Germany
| | - Jacqueline Priebe
- Department of Chemistry, Sekr. PC14, Technische Universität Berlin, 10623 Berlin, Germany
| | - Michael Haumann
- Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Ingo Zebger
- Department of Chemistry, Sekr. PC14, Technische Universität Berlin, 10623 Berlin, Germany
| | - Oliver Lenz
- Department of Chemistry, Sekr. PC14, Technische Universität Berlin, 10623 Berlin, Germany
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Bongartz H, Hessenkemper W, Müller C, Fensky M, Fritsch J, Mandel K, Behrmann I, Haan C, Fischer T, Feller SM, Schaper F. The multi-site docking protein Gab1 is constitutively phosphorylated independent from its recruitment to the plasma membrane in Jak2-V617F-positive cells and mediates proliferation of human erythroleukaemia cells. Cell Signal 2017; 35:37-47. [PMID: 28365441 DOI: 10.1016/j.cellsig.2017.03.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 02/28/2017] [Accepted: 03/26/2017] [Indexed: 10/19/2022]
Abstract
The constitutively active Janus kinase 2 mutant Jak2-V617F is responsible for cytokine-independent growth of hematopoietic cells and the development of myeloproliferative neoplasms, such as polycythaemia vera and essential thrombocythaemia. Cells expressing Jak2-V617F exhibit constitutive STAT, MAPK, and PI3K signalling, and constitutive association of the multi-site docking protein Gab1 to PIP3 at the plasma membrane. Here, we demonstrate the crucial role of Gab1 for the proliferation of Jak2-V617F-positive human erythroleukaemia (HEL) cells. In Jak2-V617F-expressing cells Gab1 is constitutively phosphorylated by Erk1/2 on serine residue 552, which regulates binding to PIP3. Additionally, Gab1 is constitutively phosphorylated on tyrosine residue 627. Tyrosine 627 is a SHP2 binding site and required for Gab1-dependent Erk1/2 activation. As previously shown, Jak2-V617F-dependent Erk1/2 and PI3K activation act synergistically on the proliferation of Jak2-V617F-positive cells. Here, we examined whether constitutive membrane association of Gab1 explains cytokine-independent Gab1 phosphorylation in Jak2-V617F-expressing cells. Although we could demonstrate Jak2-V617F-dependent constitutive serine 552 and tyrosine 627 phosphorylation of Gab1, interestingly, both phosphorylations do not require binding of Gab1 to PIP3 at the plasma membrane. Instead, we observed a constitutive interaction of Gab1 with the erythropoietin receptor in Jak2-V617F-expressing cells, which depends on Janus kinase activity. Thus, constitutive Gab1-dependent signalling in Jak2-V617F-expressing cells does not occur due to the constitutive association of Gab1 with PIP3 at the plasma membrane.
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Affiliation(s)
- Hannes Bongartz
- Institute of Biology, Department of Systems Biology, Otto-von-Guericke University, Universitätsplatz 2, 39106 Magdeburg, Germany.
| | - Wiebke Hessenkemper
- Institute of Biology, Department of Systems Biology, Otto-von-Guericke University, Universitätsplatz 2, 39106 Magdeburg, Germany.
| | - Christian Müller
- Department of Hematology and Oncology, Medical Center, Otto-von-Guericke University, Leipziger Straße 44, 39120 Magdeburg, Germany.
| | - Melissa Fensky
- Institute of Biology, Department of Systems Biology, Otto-von-Guericke University, Universitätsplatz 2, 39106 Magdeburg, Germany.
| | - Johannes Fritsch
- Institute of Biology, Department of Systems Biology, Otto-von-Guericke University, Universitätsplatz 2, 39106 Magdeburg, Germany.
| | - Katharina Mandel
- Institute of Molecular Medicine, Martin-Luther-University Halle-Wittenberg, ZAMED, Heinrich-Damerow-Straße 1, 06120 Halle, Germany.
| | - Iris Behrmann
- University of Luxembourg, Signal Transduction Laboratory, Life Sciences Research Unit, 6, avenue du Swing, L-4367 Belvaux, Luxembourg.
| | - Claude Haan
- University of Luxembourg, Signal Transduction Laboratory, Life Sciences Research Unit, 6, avenue du Swing, L-4367 Belvaux, Luxembourg.
| | - Thomas Fischer
- Department of Hematology and Oncology, Medical Center, Otto-von-Guericke University, Leipziger Straße 44, 39120 Magdeburg, Germany; Health Campus Immunology, Infectiology and Inflammation, Otto-von-Guericke-University, Leipziger Straße 44, 39120 Magdeburg, Germany.
| | - Stephan M Feller
- Institute of Molecular Medicine, Martin-Luther-University Halle-Wittenberg, ZAMED, Heinrich-Damerow-Straße 1, 06120 Halle, Germany.
| | - Fred Schaper
- Institute of Biology, Department of Systems Biology, Otto-von-Guericke University, Universitätsplatz 2, 39106 Magdeburg, Germany.
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Chhuon C, Pranke I, Borot F, Tondelier D, Lipecka J, Fritsch J, Chanson M, Edelman A, Ollero M, Guerrera I. Changes in lipid raft proteome upon TNF-α stimulation of cystic fibrosis cells. J Proteomics 2016; 145:246-253. [DOI: 10.1016/j.jprot.2016.07.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 05/20/2016] [Accepted: 07/03/2016] [Indexed: 01/22/2023]
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Fritsch J, Neumeyer C. Colour Constancy in Goldfish—The Role of Surround Reflectance. Perception 2016. [DOI: 10.1068/v96l0405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Simultaneous colour contrast as well as colour constancy have been shown quantitatively for the goldfish. In behavioural experiments we investigated colour constancy in goldfish for green and purple colours. Two fish were trained with food rewards to select one of ten test-fields in hues ranging, in small steps of saturation, from deep green, through grey, to deep purple. In the training situation the whole disk was illuminated by white light, whereas in the test situation it was changed to green and purple light, respectively. The role of surround reflectance was investigated by presenting the test fields either on a black or on a white surround. With a black surround (low reflectance) in purple illumination the fish chose test fields that were more green than the training field indicating imperfect colour constancy. With a white surround (high reflectance), however, the fish chose testfields that were more purple. This ‘overcompensation’ indicates that a white surround induces a hue complementary to that of the illumination. A similar phenomenon is known as the Helson — Judd effect in human colour vision. For green illumination the phenomenon was similar. The effect could be decreased by reducing the white surround to small white annuli around the test fields. A decrease was also achieved by separating the white surround from the test fields by black annuli. Perfect colour constancy could thus be obtained with a certain size of a white surround as well as with a certain size of separation. We therefore assume that lateral interactions play an important role in colour constancy.
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Hessenkemper W, Bongartz H, Fritsch J, Wolf A, Eulenfeld R, Simister PC, Feller SM, Schaper F. ID: 58. Cytokine 2015. [DOI: 10.1016/j.cyto.2015.08.088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Siebert E, Rippers Y, Frielingsdorf S, Fritsch J, Schmidt A, Kalms J, Katz S, Lenz O, Scheerer P, Paasche L, Pelmenschikov V, Kuhlmann U, Mroginski MA, Zebger I, Hildebrandt P. Resonance Raman Spectroscopic Analysis of the [NiFe] Active Site and the Proximal [4Fe-3S] Cluster of an O2-Tolerant Membrane-Bound Hydrogenase in the Crystalline State. J Phys Chem B 2015. [DOI: 10.1021/acs.jpcb.5b04119] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Elisabeth Siebert
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Yvonne Rippers
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Stefan Frielingsdorf
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Johannes Fritsch
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Andrea Schmidt
- Charité − Universitätsmedizin Berlin, Institut für Medizinische Physik und Biophysik (CC2), Group
Protein X-ray Crystallography and Signal Transduction, Charitéplatz 1, D-10117 Berlin, Germany
| | - Jacqueline Kalms
- Charité − Universitätsmedizin Berlin, Institut für Medizinische Physik und Biophysik (CC2), Group
Protein X-ray Crystallography and Signal Transduction, Charitéplatz 1, D-10117 Berlin, Germany
| | - Sagie Katz
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Oliver Lenz
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Patrick Scheerer
- Charité − Universitätsmedizin Berlin, Institut für Medizinische Physik und Biophysik (CC2), Group
Protein X-ray Crystallography and Signal Transduction, Charitéplatz 1, D-10117 Berlin, Germany
| | - Lars Paasche
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Vladimir Pelmenschikov
- Technische
Universität Berlin, Institut für Chemie, Sekr. C7, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Uwe Kuhlmann
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Maria Andrea Mroginski
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Ingo Zebger
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Peter Hildebrandt
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
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Fritsch J, Fouillet T, Charles P, Fargier-Puech P, Ramponi-Bur C, Descamps S, Du Fretay G, Myrta A. FRENCH EXPERIENCES WITH DIMETHYL DISULFIDE (DMDS) AS A NEMATICIDE IN VEGETABLE CROPS. ACTA ACUST UNITED AC 2014. [DOI: 10.17660/actahortic.2014.1044.59] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Frielingsdorf S, Fritsch J, Schmidt A, Hammer M, Löwenstein J, Siebert E, Pelmenschikov V, Jaenicke T, Kalms J, Rippers Y, Lendzian F, Zebger I, Teutloff C, Kaupp M, Bittl R, Hildebrandt P, Friedrich B, Lenz O, Scheerer P. Reversible [4Fe-3S] cluster morphing in an O2-tolerant [NiFe] hydrogenase. Nat Chem Biol 2014; 10:378-85. [DOI: 10.1038/nchembio.1500] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 03/13/2014] [Indexed: 12/27/2022]
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Fritsch J, Siebert E, Priebe J, Zebger I, Lendzian F, Teutloff C, Friedrich B, Lenz O. Rubredoxin-related maturation factor guarantees metal cofactor integrity during aerobic biosynthesis of membrane-bound [NiFe] hydrogenase. J Biol Chem 2014; 289:7982-93. [PMID: 24448806 DOI: 10.1074/jbc.m113.544668] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The membrane-bound [NiFe] hydrogenase (MBH) supports growth of Ralstonia eutropha H16 with H2 as the sole energy source. The enzyme undergoes a complex biosynthesis process that proceeds during cell growth even at ambient O2 levels and involves 14 specific maturation proteins. One of these is a rubredoxin-like protein, which is essential for biosynthesis of active MBH at high oxygen concentrations but dispensable under microaerobic growth conditions. To obtain insights into the function of HoxR, we investigated the MBH protein purified from the cytoplasmic membrane of hoxR mutant cells. Compared with wild-type MBH, the mutant enzyme displayed severely decreased hydrogenase activity. Electron paramagnetic resonance and infrared spectroscopic analyses revealed features resembling those of O2-sensitive [NiFe] hydrogenases and/or oxidatively damaged protein. The catalytic center resided partially in an inactive Niu-A-like state, and the electron transfer chain consisting of three different Fe-S clusters showed marked alterations compared with wild-type enzyme. Purification of HoxR protein from its original host, R. eutropha, revealed only low protein amounts. Therefore, recombinant HoxR protein was isolated from Escherichia coli. Unlike common rubredoxins, the HoxR protein was colorless, rather unstable, and essentially metal-free. Conversion of the atypical iron-binding motif into a canonical one through genetic engineering led to a stable reddish rubredoxin. Remarkably, the modified HoxR protein did not support MBH-dependent growth at high O2. Analysis of MBH-associated protein complexes points toward a specific interaction of HoxR with the Fe-S cluster-bearing small subunit. This supports the previously made notion that HoxR avoids oxidative damage of the metal centers of the MBH, in particular the unprecedented Cys6[4Fe-3S] cluster.
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Affiliation(s)
- Johannes Fritsch
- From the Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Chausseestrasse 117, 10115 Berlin
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Siebert E, Horch M, Rippers Y, Fritsch J, Frielingsdorf S, Lenz O, Velazquez Escobar F, Siebert F, Paasche L, Kuhlmann U, Lendzian F, Mroginski M, Zebger I, Hildebrandt P. Back Cover: Resonance Raman Spectroscopy as a Tool to Monitor the Active Site of Hydrogenases (Angew. Chem. Int. Ed. 19/2013). Angew Chem Int Ed Engl 2013. [DOI: 10.1002/anie.201302121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Elisabeth Siebert
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Marius Horch
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Yvonne Rippers
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Johannes Fritsch
- Institut für Biologie/Mikrobiologie, Humboldt Universität zu Berlin, Chausseestrasse 117, 10115 Berlin (Germany)
| | - Stefan Frielingsdorf
- Institut für Biologie/Mikrobiologie, Humboldt Universität zu Berlin, Chausseestrasse 117, 10115 Berlin (Germany)
| | - Oliver Lenz
- Institut für Biologie/Mikrobiologie, Humboldt Universität zu Berlin, Chausseestrasse 117, 10115 Berlin (Germany)
| | - Francisco Velazquez Escobar
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Friedrich Siebert
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Lars Paasche
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Uwe Kuhlmann
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Friedhelm Lendzian
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Maria‐Andrea Mroginski
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Ingo Zebger
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Peter Hildebrandt
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
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Siebert E, Horch M, Rippers Y, Fritsch J, Frielingsdorf S, Lenz O, Velazquez Escobar F, Siebert F, Paasche L, Kuhlmann U, Lendzian F, Mroginski MA, Zebger I, Hildebrandt P. Rücktitelbild: Resonanz-Raman-Spektroskopie als Methode zur Untersuchung des aktiven Zentrums von Hydrogenasen (Angew. Chem. 19/2013). Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201302121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Siebert E, Horch M, Rippers Y, Fritsch J, Frielingsdorf S, Lenz O, Velazquez Escobar F, Siebert F, Paasche L, Kuhlmann U, Lendzian F, Mroginski M, Zebger I, Hildebrandt P. Resonance Raman Spectroscopy as a Tool to Monitor the Active Site of Hydrogenases. Angew Chem Int Ed Engl 2013; 52:5162-5. [DOI: 10.1002/anie.201209732] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/22/2013] [Indexed: 11/06/2022]
Affiliation(s)
- Elisabeth Siebert
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Marius Horch
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Yvonne Rippers
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Johannes Fritsch
- Institut für Biologie/Mikrobiologie, Humboldt Universität zu Berlin, Chausseestrasse 117, 10115 Berlin (Germany)
| | - Stefan Frielingsdorf
- Institut für Biologie/Mikrobiologie, Humboldt Universität zu Berlin, Chausseestrasse 117, 10115 Berlin (Germany)
| | - Oliver Lenz
- Institut für Biologie/Mikrobiologie, Humboldt Universität zu Berlin, Chausseestrasse 117, 10115 Berlin (Germany)
| | - Francisco Velazquez Escobar
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Friedrich Siebert
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Lars Paasche
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Uwe Kuhlmann
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Friedhelm Lendzian
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Maria‐Andrea Mroginski
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Ingo Zebger
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Peter Hildebrandt
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
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Siebert E, Horch M, Rippers Y, Fritsch J, Frielingsdorf S, Lenz O, Velazquez Escobar F, Siebert F, Paasche L, Kuhlmann U, Lendzian F, Mroginski MA, Zebger I, Hildebrandt P. Resonanz-Raman-Spektroskopie als Methode zur Untersuchung des aktiven Zentrums von Hydrogenasen. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201209732] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
Ceramic filters, working on the depth filtration principle, are known to improve drinking water quality by removing human pathogenic microorganisms from contaminated water. However, these microfilters show no sufficient barrier for viruses having diameters down to 20 nm. Recently, it was shown that the addition of positively charged materials, for example, iron oxyhydroxide, can improve virus removal by adsorption mechanisms. In this work, we modified a common ceramic filter based on diatomaceous earth by introducing a novel virus adsorbent material, magnesium oxyhydroxide, into the filter matrix. Such filters showed an improved removal of about 4-log in regard to bacteriophages MS2 and PhiX174. This is explained with the electrostatic enhanced adsorption approach that is the favorable adsorption of negatively charged viruses onto positively charged patches in an otherwise negatively charged filter matrix. Furthermore, we provide theoretical evidence applying calculations according to Derjaguin-Landau-Verwey-Overbeek theory to strengthen our experimental results. However, modified filters showed a significant variance in virus removal efficiency over the course of long-term filtration experiments with virus removal increasing with filter operation time (or filter aging). This is explained by transformational changes of MgO in the filter upon contact with water. It also demonstrates that filter history is of great concern when filters working on the adsorption principles are evaluated in regard to their retention performance as their surface characteristics may alter with use.
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Affiliation(s)
- Benjamin Michen
- Laboratory for High Performance Ceramics, EMPA, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, CH-8600 Duebendorf, Switzerland.
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Gillitzer R, Farasaty-Ghazwiny M, Fritsch J, Schede J, Hampel C. V1892 EARLY RESULTS WITH A TOTALLY EXTRAPERITONEAL ILEAL CONDUIT. J Urol 2012. [DOI: 10.1016/j.juro.2012.02.2047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Jeanson L, Kelly M, Coste A, Guerrera IC, Fritsch J, Nguyen-Khoa T, Baudouin-Legros M, Papon JF, Zadigue P, Prulière-Escabasse V, Amselem S, Escudier E, Edelman A. Oxidative stress induces unfolding protein response and inflammation in nasal polyposis. Allergy 2012; 67:403-12. [PMID: 22188019 DOI: 10.1111/j.1398-9995.2011.02769.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2011] [Indexed: 12/12/2022]
Abstract
BACKGROUND Nasal polyposis, a chronic inflammatory disease affecting the upper airways, is a valuable and accessible model to investigate the mechanisms underlying chronic inflammation. The main objective of this study was to investigate a potential involvement of the unfolded protein response (UPR) in the context of oxidative stress and inflammation in nasal epithelial cells from nasal polyps (NP). METHODS Epithelial cells from NP (n = 20) and normal mucosa (Controls, n = 15) in primary culture were analyzed by global proteomic approach and cell biology techniques for the glucose-regulated protein 78 (GRP78), the spliced X-box-binding protein 1 (sXBP-1), the glucose-regulated protein 94 (GRP94), and the calreticulin (immunoblot, mass spectrometry, immunocytochemistry). RESULTS Proteomics analysis of human nasal epithelial cells in culture revealed the activation of the unfolded protein response in NP. Systematic cell biology and biochemical analysis of two markers (GRP78, sXBP-1) in the presence and absence of oxidative stress in NP showed a susceptibility of the unfolded protein response to oxidative stress compared to controls at least partially linked to an abnormal redox state of the protein disulfide-isomerase 4. This unfolded protein response was correlated with mitochondrial depolarization and secretion of interleukin 8 (IL-8) and leukotriene B4 (LTB4) and was prevented by mitochondrial antioxidant. CONCLUSIONS We show the existence of UPR in nasal epithelial cells that is linked to oxidative stress leading to IL-8 and LTB4 secretions. These mechanisms may participate in chronic inflammation in nasal polyposis.
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Affiliation(s)
| | - M. Kelly
- INSERM; U845; Université Paris Descartes; Paris; France
| | | | | | - J. Fritsch
- INSERM; U845; Université Paris Descartes; Paris; France
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Michen B, Meder F, Rust A, Fritsch J, Aneziris C, Graule T. Virus removal in ceramic depth filters based on diatomaceous earth. Environ Sci Technol 2012; 46:1170-7. [PMID: 22191487 DOI: 10.1021/es2030565] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Ceramic filter candles, based on the natural material diatomaceous earth, are widely used to purify water at the point-of-use. Although such depth filters are known to improve drinking water quality by removing human pathogenic protozoa and bacteria, their removal regarding viruses has rarely been investigated. These filters have relatively large pore diameters compared to the physical dimension of viruses. However, viruses may be retained by adsorption mechanisms due to intermolecular and surface forces. Here, we use three types of bacteriophages to investigate their removal during filtration and batch experiments conducted at different pH values and ionic strengths. Theoretical models based on DLVO-theory are applied in order to verify experimental results and assess surface forces involved in the adsorptive process. This was done by calculation of interaction energies between the filter surface and the viruses. For two small spherically shaped viruses (MS2 and PhiX174), these filters showed no significant removal. In the case of phage PhiX174, where attractive interactions were expected, due to electrostatic attraction of oppositely charged surfaces, only little adsorption was reported in the presence of divalent ions. Thus, we postulate the existence of an additional repulsive force between PhiX174 and the filter surface. It is hypothesized that such an additional energy barrier originates from either the phage's specific knobs that protrude from the viral capsid, enabling steric interactions, or hydration forces between the two hydrophilic interfaces of virus and filter. However, a larger-sized, tailed bacteriophage of the family Siphoviridae was removed by log 2 to 3, which is explained by postulating hydrophobic interactions.
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Affiliation(s)
- Benjamin Michen
- Laboratory for High Performance Ceramics, EMPA, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600 Duebendorf, Switzerland.
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Fritsch J, Scheerer P, Frielingsdorf S, Kroschinsky S, Friedrich B, Lenz O, Spahn CMT. The crystal structure of an oxygen-tolerant hydrogenase uncovers a novel iron-sulphur centre. Nature 2011; 479:249-52. [PMID: 22002606 DOI: 10.1038/nature10505] [Citation(s) in RCA: 255] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 08/23/2011] [Indexed: 11/10/2022]
Abstract
Hydrogenases are abundant enzymes that catalyse the reversible interconversion of H(2) into protons and electrons at high rates. Those hydrogenases maintaining their activity in the presence of O(2) are considered to be central to H(2)-based technologies, such as enzymatic fuel cells and for light-driven H(2) production. Despite comprehensive genetic, biochemical, electrochemical and spectroscopic investigations, the molecular background allowing a structural interpretation of how the catalytic centre is protected from irreversible inactivation by O(2) has remained unclear. Here we present the crystal structure of an O(2)-tolerant [NiFe]-hydrogenase from the aerobic H(2) oxidizer Ralstonia eutropha H16 at 1.5 Å resolution. The heterodimeric enzyme consists of a large subunit harbouring the catalytic centre in the H(2)-reduced state and a small subunit containing an electron relay consisting of three different iron-sulphur clusters. The cluster proximal to the active site displays an unprecedented [4Fe-3S] structure and is coordinated by six cysteines. According to the current model, this cofactor operates as an electronic switch depending on the nature of the gas molecule approaching the active site. It serves as an electron acceptor in the course of H(2) oxidation and as an electron-delivering device upon O(2) attack at the active site. This dual function is supported by the capability of the novel iron-sulphur cluster to adopt three redox states at physiological redox potentials. The second structural feature is a network of extended water cavities that may act as a channel facilitating the removal of water produced at the [NiFe] active site. These discoveries will have an impact on the design of biological and chemical H(2)-converting catalysts that are capable of cycling H(2) in air.
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Affiliation(s)
- Johannes Fritsch
- Mikrobiologie, Institut für Biologie, Humboldt-Universität zu Berlin, Chausseestraße 117, 10115 Berlin, Germany
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Affiliation(s)
- Rolf Gillitzer
- Urologische Klinik, Klinikum Darmstadt GmbH, Darmstadt, Germany
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Fritsch J, Mansfeld D, Mehring M, Wursche R, Grothe J, Kaskel S. Refractive index tuning of highly transparent bismuth containing polymer composites. POLYMER 2011. [DOI: 10.1016/j.polymer.2011.05.046] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Michen B, Diatta A, Fritsch J, Aneziris C, Graule T. Removal of colloidal particles in ceramic depth filters based on diatomaceous earth. Sep Purif Technol 2011. [DOI: 10.1016/j.seppur.2011.07.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Fritsch J, Löscher S, Sanganas O, Siebert E, Zebger I, Stein M, Ludwig M, De Lacey AL, Dau H, Friedrich B, Lenz O, Haumann M. [NiFe] and [FeS] Cofactors in the Membrane-Bound Hydrogenase of Ralstonia eutropha Investigated by X-ray Absorption Spectroscopy: Insights into O2-Tolerant H2 Cleavage. Biochemistry 2011; 50:5858-69. [DOI: 10.1021/bi200367u] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Johannes Fritsch
- Humboldt-Universität zu Berlin, Institut für Biologie/Mikrobiologie, 10115 Berlin, Germany
| | - Simone Löscher
- Freie Universität Berlin, Institut für Experimentalphysik, 14195 Berlin, Germany
| | - Oliver Sanganas
- Freie Universität Berlin, Institut für Experimentalphysik, 14195 Berlin, Germany
| | - Elisabeth Siebert
- Technische Universität Berlin, Max-Volmer Institut, 10623 Berlin, Germany
| | - Ingo Zebger
- Technische Universität Berlin, Max-Volmer Institut, 10623 Berlin, Germany
| | - Matthias Stein
- Max-Planck-Institut für Dynamik komplexer technischer Systeme, 39106 Magdeburg, Germany
| | - Marcus Ludwig
- Humboldt-Universität zu Berlin, Institut für Biologie/Mikrobiologie, 10115 Berlin, Germany
| | | | - Holger Dau
- Freie Universität Berlin, Institut für Experimentalphysik, 14195 Berlin, Germany
| | - Bärbel Friedrich
- Humboldt-Universität zu Berlin, Institut für Biologie/Mikrobiologie, 10115 Berlin, Germany
| | - Oliver Lenz
- Humboldt-Universität zu Berlin, Institut für Biologie/Mikrobiologie, 10115 Berlin, Germany
| | - Michael Haumann
- Freie Universität Berlin, Institut für Experimentalphysik, 14195 Berlin, Germany
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Friedrich B, Fritsch J, Lenz O. Oxygen-tolerant hydrogenases in hydrogen-based technologies. Curr Opin Biotechnol 2011; 22:358-64. [DOI: 10.1016/j.copbio.2011.01.006] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Revised: 01/20/2011] [Accepted: 01/21/2011] [Indexed: 12/30/2022]
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Kelly-Aubert M, Trudel S, Fritsch J, Nguyen-Khoa T, Baudouin-Legros M, Moriceau S, Jeanson L, Djouadi F, Matar C, Conti M, Ollero M, Brouillard F, Edelman A. GSH monoethyl ester rescues mitochondrial defects in cystic fibrosis models. Hum Mol Genet 2011; 20:2745-59. [DOI: 10.1093/hmg/ddr173] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Goris T, Wait AF, Saggu M, Fritsch J, Heidary N, Stein M, Zebger I, Lendzian F, Armstrong FA, Friedrich B, Lenz O. A unique iron-sulfur cluster is crucial for oxygen tolerance of a [NiFe]-hydrogenase. Nat Chem Biol 2011; 7:310-8. [PMID: 21390036 DOI: 10.1038/nchembio.555] [Citation(s) in RCA: 196] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Accepted: 03/01/2011] [Indexed: 12/11/2022]
Abstract
Hydrogenases are essential for H(2) cycling in microbial metabolism and serve as valuable blueprints for H(2)-based biotechnological applications. However, most hydrogenases are extremely oxygen sensitive and prone to inactivation by even traces of O(2). The O(2)-tolerant membrane-bound [NiFe]-hydrogenase of Ralstonia eutropha H16 is one of the few examples that can perform H(2) uptake in the presence of ambient O(2). Here we show that O(2) tolerance is crucially related to a modification of the internal electron-transfer chain. The iron-sulfur cluster proximal to the active site is surrounded by six instead of four conserved coordinating cysteines. Removal of the two additional cysteines alters the electronic structure of the proximal iron-sulfur cluster and renders the catalytic activity sensitive to O(2) as shown by physiological, biochemical, spectroscopic and electrochemical studies. The data indicate that the mechanism of O(2) tolerance relies on the reductive removal of oxygenic species guided by the unique architecture of the electron relay rather than a restricted access of O(2) to the active site.
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Affiliation(s)
- Tobias Goris
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Berlin, Germany
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Tuvignon N, Liguory C, Ponchon T, Meduri B, Fritsch J, Sahel J, Boyer J, Legoux JL, Escourrou J, Boustiere C, Arpurt JP, Barthet M, Tuvignon P, Bommelaer G, Ducot B, Prat F. Long-term follow-up after biliary stent placement for postcholecystectomy bile duct strictures: a multicenter study. Endoscopy 2011; 43:208-16. [PMID: 21365514 DOI: 10.1055/s-0030-1256106] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
BACKGROUND AND STUDY AIMS Endoscopic stenting is a recognized treatment of postcholecystectomy biliary strictures. Large multicenter reports of its long-term efficacy are lacking. Our aim was to analyze the long-term outcomes after stenting in this patient population, based on a large experience from several centers in France. METHODS Members of the French Society of Digestive Endoscopy were asked to identify patients treated for a common bile duct postcholecystectomy stricture. Patients with successful stenting and follow-up after removal of stent(s) were subsequently included and analyzed. Main outcome measures were long-term success of endoscopic stenting and related predictors for recurrence (after one stenting period) or failure (at the end of follow-up). RESULTS A total of 96 patients were eligible for inclusion. The mean number of stents inserted at the same time was 1.9±0.89 (range 1-4). Stent-related morbidity was 22.9% (n=22). The median duration of stenting was 12 months (range 2-96 months). After a mean follow-up of 6.4±3.8 years (range 0-20.3 years) the overall success rate was 66.7% (n=64) after one period of stenting and 82.3% (n=79) after additional treatments. The mean time to recurrence was 19.7±36.6 months. The most significant independent predictor of both recurrence and failure was a pathological cholangiography at the time of stent removal. CONCLUSION Endoscopic stenting helps to avoid surgery in more than 80% of patients bearing postcholecystectomy common bile duct strictures. However, a persistent anomaly on cholangiography at the time of stent removal is a strong predictor of recurrence and may lead to consideration of surgery.
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Affiliation(s)
- N Tuvignon
- Gastroenterology Department, Cochin Hospital, Paris, France
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Edelman A, Fritsch J, Ollero M. Twenty years after cystic fibrosis gene identification: Where are we and what are we up to? ACTA ACUST UNITED AC 2009; 59:131-3. [PMID: 19896304 DOI: 10.1016/j.patbio.2009.05.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Accepted: 05/15/2009] [Indexed: 11/25/2022]
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Trudel S, Kelly M, Thérond P, Nguyen-Khoa T, Dadlez M, Ollero M, Roussel D, Fritsch J, Edelman A, Brouillard F. Evaluation of oxidant and antioxidant status in CFTR-KO mice: role of Peroxiredoxin 6. J Cyst Fibros 2009. [DOI: 10.1016/s1569-1993(09)60212-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Colas J, Faure G, Trudel S, Fritsch J, Guerrera C, Davezac N, Brouillard F, Herrmann H, Ollero M, Edelman A. Increased interaction of F508del-CFTR with K8/K18 cytokeratin network by direct binding of K8 to NBD1. J Cyst Fibros 2009. [DOI: 10.1016/s1569-1993(09)60087-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Fritsch J, Moraru CI. Development and optimization of a carbon dioxide-aided cold microfiltration process for the physical removal of microorganisms and somatic cells from skim milk. J Dairy Sci 2009; 91:3744-60. [PMID: 18832196 DOI: 10.3168/jds.2007-0899] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Physical removal of microorganisms from skim milk by microfiltration (MF) is becoming increasingly attractive to the dairy industry. Typically, this process is performed at temperatures of approximately 50 degrees C. Additional shelf-life and quality benefits might be gained by conducting the MF process at low temperatures. Cold MF could also minimize microbial fouling of the membrane and prevent the germination of thermophilic spores. The objective of this study was to optimize a cold MF process for the effective removal of microbial and somatic cells from skim milk. An experimental MF setup containing a tubular Tami ceramic membrane with a nominal pore size of 1.4 microm was used for MF of raw skim milk at a temperature of 6 +/- 1 degrees C. The processing conditions used were cross-flow velocities of 5 to 7 m/s, and transmembrane pressures of 52 to 131 kPa. All MF experiments were performed in triplicate. The permeate flux was determined gravimetrically. Microbiological, chemical, and somatic cell analyses were performed to evaluate the effect of MF on the composition of skim milk. The permeate flux increased drastically when velocity was increased from 5 to 7 m/s. The critical transmembrane pressure range conducive to maximum fluxes was 60 to 85 kPa. When MF was conducted under optimal conditions, very efficient removal of vegetative bacteria, spores, and somatic cells, as well as near complete transmission of proteins into the MF milk, was achieved. To further enhance the flux, a CO(2) backpulsing system was developed. This technique is able both to increase the flux and to maintain it steadily for an extended period of time. The CO(2)-aided cold MF process has the potential to become economically attractive to the dairy industry, with direct benefits for the quality and shelf life of dairy products.
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Affiliation(s)
- J Fritsch
- Department of Food Science, Cornell University, Ithaca, NY 14853, USA
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Sermet-Gaudelus I, Nove-Josserand R, Loeille GA, Dacremont G, Souberbielle JC, Fritsch J, Laurans M, Moulin P, Cortet B, Salles JP, Ginies JL, Guillot M, Perez-Martin S, Ruiz JC, Montagne V, Cohen-Solal M, Cormier C, Garabédian M, Mallet E. Recommandations pour la prise en charge de la déminéralisation osseuse dans la mucoviscidose. Arch Pediatr 2008; 15:301-12. [DOI: 10.1016/j.arcped.2007.12.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Revised: 11/30/2007] [Accepted: 12/11/2007] [Indexed: 11/26/2022]
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Wegmann M, Michen B, Luxbacher T, Fritsch J, Graule T. Modification of ceramic microfilters with colloidal zirconia to promote the adsorption of viruses from water. Water Res 2008; 42:1726-34. [PMID: 17996271 DOI: 10.1016/j.watres.2007.10.030] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Revised: 10/22/2007] [Accepted: 10/22/2007] [Indexed: 05/08/2023]
Abstract
The purpose of this study was to test the feasibility of modifying commercial microporous ceramic bacteria filters to promote adsorption of viruses. The internal surface of the filter medium was coated with ZrO(2) nanopowder via dip-coating and heat-treatment in order to impart a filter surface charge opposite to that of the target viruses. Streaming potential measurements revealed a shift in the isoelectric point from pH <3 to between pH 5.5 and 9, respectively. While the base filter elements generally exhibited only 75% retention with respect to MS2 bacteriophages, the modified elements achieved a 7log removal (99.99999%) of these virus-like particles. The coating process also increased the specific surface area of the filters from approximately 2m(2)/g to between 12.5 and 25.5m(2)/g, thereby also potentially increasing their adsorption capacity. The results demonstrate that, given more development effort, the chosen manufacturing process has the potential to yield effective virus filters with throughputs superior to those of current virus filtration techniques.
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Affiliation(s)
- Markus Wegmann
- Swiss Federal Laboratories for Materials Testing and Research, CH-8600 Dübendorf, Switzerland
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Dill T, Klute A, Fritsch J, Kleinschmidt K. Ergebnisse nach adjuvanter Chemotherapie mit Carboplatin beim Seminom im Stadium I. Aktuelle Urol 2006. [DOI: 10.1055/s-2006-947405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Fritsch J, Stille W, Strobl G. Investigation of polymer crystallization kinetics with time dependent light attenuation measurements. Colloid Polym Sci 2006. [DOI: 10.1007/s00396-005-1408-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Borot F, Hinzpeter A, Brouillard F, Bensalem N, Tondelier D, Fritsch J, Edelman A, Ollero M. 035 Localisation du CFTR dans les microdomaines lipidiques membranaires de cellules Calu3. Rev Mal Respir 2005. [DOI: 10.1016/s0761-8425(05)92447-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Prat F, Cosson C, Domingo N, Chapat O, Fompeydie D, Nassar N, Fritsch J, Choury AD, Pelletier G, Buffet C. Study of the mechanisms of biliary stent occlusion: an analysis of occluded and nonoccluded stents, with emphasis on the role of antinucleating biliary anionic Peptide factor. Endoscopy 2004; 36:322-8. [PMID: 15057682 DOI: 10.1055/s-2004-814411] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- F Prat
- Dept. of Hepatogastroenterology, Centre Hospitalier Universitaire Bicêtre, Le Kremlin-Bicêtre, France.
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