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Kessler N, Viehmann SF, Krollmann C, Mai K, Kirschner KM, Luksch H, Kotagiri P, Böhner AMC, Huugen D, de Oliveira Mann CC, Otten S, Weiss SAI, Zillinger T, Dobrikova K, Jenne DE, Behrendt R, Ablasser A, Bartok E, Hartmann G, Hopfner KP, Lyons PA, Boor P, Rösen-Wolff A, Teichmann LL, Heeringa P, Kurts C, Garbi N. Correction: Monocyte-derived macrophages aggravate pulmonary vasculitis via cGAS/STING/IFN-mediated nucleic acid sensing. J Exp Med 2022; 219:213681. [PMID: 36367753 PMCID: PMC9663832 DOI: 10.1084/jem.2022075911022022c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Kessler N, Viehmann SF, Krollmann C, Mai K, Kirschner KM, Luksch H, Kotagiri P, Böhner AM, Huugen D, de Oliveira Mann CC, Otten S, Weiss SA, Zillinger T, Dobrikova K, Jenne DE, Behrendt R, Ablasser A, Bartok E, Hartmann G, Hopfner KP, Lyons PA, Boor P, Rösen-Wolff A, Teichmann LL, Heeringa P, Kurts C, Garbi N. Monocyte-derived macrophages aggravate pulmonary vasculitis via cGAS/STING/IFN-mediated nucleic acid sensing. J Exp Med 2022; 219:213416. [PMID: 35997679 PMCID: PMC9402992 DOI: 10.1084/jem.20220759] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 07/07/2022] [Accepted: 08/03/2022] [Indexed: 11/04/2022] Open
Abstract
Autoimmune vasculitis is a group of life-threatening diseases, whose underlying pathogenic mechanisms are incompletely understood, hampering development of targeted therapies. Here, we demonstrate that patients suffering from anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) showed increased levels of cGAMP and enhanced IFN-I signature. To identify disease mechanisms and potential therapeutic targets, we developed a mouse model for pulmonary AAV that mimics severe disease in patients. Immunogenic DNA accumulated during disease onset, triggering cGAS/STING/IRF3-dependent IFN-I release that promoted endothelial damage, pulmonary hemorrhages, and lung dysfunction. Macrophage subsets played dichotomic roles in disease. While recruited monocyte-derived macrophages were major disease drivers by producing most IFN-β, resident alveolar macrophages contributed to tissue homeostasis by clearing red blood cells and limiting infiltration of IFN-β-producing macrophages. Moreover, pharmacological inhibition of STING, IFNAR-I, or its downstream JAK/STAT signaling reduced disease severity and accelerated recovery. Our study unveils the importance of STING/IFN-I axis in promoting pulmonary AAV progression and identifies cellular and molecular targets to ameliorate disease outcomes.
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Affiliation(s)
- Nina Kessler
- Institute of Molecular Medicine and Experimental Immunology, Medical Faculty, University of Bonn, Bonn, Germany,Nina Kessler:
| | - Susanne F. Viehmann
- Institute of Molecular Medicine and Experimental Immunology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Calvin Krollmann
- Medical Clinic and Polyclinic III, University Hospital Bonn, Bonn, Germany
| | - Karola Mai
- Institute of Molecular Medicine and Experimental Immunology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Katharina M. Kirschner
- Institute of Molecular Medicine and Experimental Immunology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Hella Luksch
- Department of Pediatrics, Universitätsklinikum Carl Gustav Carus TU Dresden, Dresden, Germany
| | - Prasanti Kotagiri
- Department of Medicine, University of Cambridge School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Alexander M.C. Böhner
- Institute of Molecular Medicine and Experimental Immunology, Medical Faculty, University of Bonn, Bonn, Germany,Department of Radiation Oncology, University Hospital Bonn, Bonn, Germany
| | - Dennis Huugen
- Department of Internal Medicine, Division of Clinical and Experimental Immunology, University of Maastricht, Maastricht, Netherlands
| | | | - Simon Otten
- Institute of Pathology, University Hospital Aachen, RWTH Aachen University, Aachen, Germany
| | - Stefanie A.I. Weiss
- Comprehensive Pneumology Center, Institute of Lung Biology and Disease, Helmholtz Zentrum München and University Hospital of the Ludwig-Maximilians University, Munich, Germany
| | - Thomas Zillinger
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | - Kristiyana Dobrikova
- Institute of Molecular Medicine and Experimental Immunology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Dieter E. Jenne
- Comprehensive Pneumology Center, Institute of Lung Biology and Disease, Helmholtz Zentrum München and University Hospital of the Ludwig-Maximilians University, Munich, Germany,Max Planck Institute of Neurobiology, Planegg-Martinsried, Planegg, Germany
| | - Rayk Behrendt
- Institute for Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | - Andrea Ablasser
- Global Health Institute, Swiss Federal Institute of Technology, Lausanne, Switzerland
| | - Eva Bartok
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | - Gunther Hartmann
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | | | - Paul A. Lyons
- Department of Medicine, University of Cambridge School of Clinical Medicine, University of Cambridge, Cambridge, UK,Cambridge Institute for Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge, UK
| | - Peter Boor
- Institute of Pathology, University Hospital Aachen, RWTH Aachen University, Aachen, Germany
| | - Angela Rösen-Wolff
- Department of Pediatrics, Universitätsklinikum Carl Gustav Carus TU Dresden, Dresden, Germany
| | - Lino L. Teichmann
- Medical Clinic and Polyclinic III, University Hospital Bonn, Bonn, Germany
| | - Peter Heeringa
- Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Christian Kurts
- Institute of Molecular Medicine and Experimental Immunology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Natalio Garbi
- Institute of Molecular Medicine and Experimental Immunology, Medical Faculty, University of Bonn, Bonn, Germany,Correspondence to Natalio Garbi:
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Daeggelmann J, Otten S, Prokop A, Maas V, Streckmann F, Bloch W, Oschwald V. Correction to: Feasibility of a combined supervised and home‑based whole‑body vibration intervention in children after inpatient oncological treatment. Sport Sci Health 2021. [DOI: 10.1007/s11332-021-00807-x] [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: 11/24/2022]
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Daeggelmann J, Otten S, Prokop A, Maas V, Streckmann F, Bloch W, Oschwald V. Feasibility of a combined supervised and home-based whole-body vibration intervention in children after inpatient oncological treatment. Sport Sci Health 2021. [DOI: 10.1007/s11332-021-00770-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Abstract
Purpose
Reduced physical performance due to therapy-related dysfunctions in children diagnosed with cancer contributes to insufficient physical activity levels. It is therefore essential that relevant functions are restored. Whole-body vibration (WBV) training, a neuromuscular stimulating exercise intervention, could have the potential to target those functions adequately. Therefore, the aim of this study was to evaluate the feasibility of a combined supervised and home-based WBV intervention with children after inpatient oncological treatment.
Methods
Eight children aged 6–21 years were included after cessation of their inpatient oncological treatment. They performed a 12-week WBV training including one supervised and two home-based sessions per week according to a standardized training protocol. Feasibility, adherence and compliance to the vibration protocol were documented. Subjective benefits and satisfaction were assessed using a questionnaire.
Results
Study participants attended 84.03 ± 13.09% of WBV sessions. No serious adverse events occurred. Some patients reported side effects partially resulting in modifications of the vibration protocol by therapists. Almost all children regarded the intervention as beneficial.
Conclusion
A combined supervised and home-based WBV intervention with children after inpatient oncological treatment is feasible and safe. The beneficial potential regarding relevant sensory and motor dysfunctions is now to be investigated.
Trial registration number and date of registration
DRKS00014713 15.05.2018
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Broekstra R, Maeckelberghe ELM, Aris-Meijer JL, Stolk RP, Otten S. Motives of contributing personal data for health research: (non-)participation in a Dutch biobank. BMC Med Ethics 2020; 21:62. [PMID: 32711531 PMCID: PMC7382031 DOI: 10.1186/s12910-020-00504-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 07/14/2020] [Indexed: 01/13/2023] Open
Abstract
Background Large-scale, centralized data repositories are playing a critical and unprecedented role in fostering innovative health research, leading to new opportunities as well as dilemmas for the medical sciences. Uncovering the reasons as to why citizens do or do not contribute to such repositories, for example, to population-based biobanks, is therefore crucial. We investigated and compared the views of existing participants and non-participants on contributing to large-scale, centralized health research data repositories with those of ex-participants regarding the decision to end their participation. This comparison could yield new insights into motives of participation and non-participation, in particular the behavioural change of withdrawal. Methods We conducted 36 in-depth interviews with ex-participants, participants, and non-participants of a three-generation, population-based biobank in the Netherlands. The interviews focused on the respondents’ decision-making processes relating to their participation in a large-scale, centralized repository for health research data. Results The decision of participants and non-participants to contribute to the biobank was motivated by a desire to help others. Whereas participants perceived only benefits relating to their participation and were unconcerned about potential risks, non-participants and ex-participants raised concerns about the threat of large-scale, centralized public data repositories and public institutes, such as social exclusion or commercialization. Our analysis of ex-participants’ perceptions suggests that intrapersonal characteristics, such as levels of trust in society, participation conceived as a social norm, and basic societal values account for differences between participants and non-participants. Conclusions Our findings indicate the fluidity of motives centring on helping others in decisions to participate in large-scale, centralized health research data repositories. Efforts to improve participation should focus on enhancing the trustworthiness of such data repositories and developing layered strategies for communication with participants and with the public. Accordingly, personalized approaches for recruiting participants and transmitting information along with appropriate regulatory frameworks are required, which have important implications for current data management and informed consent procedures.
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Affiliation(s)
- R Broekstra
- Department of Epidemiology, University Medical Center Groningen, University of Groningen, PO Box 30.001, FA 40, 9700, RB, Groningen, The Netherlands. .,Department of Social Psychology, Faculty of Behavioral and Social Sciences, University of Groningen, Groningen, The Netherlands.
| | - E L M Maeckelberghe
- University Medical Center Groningen, Institute for Medical Education, University of Groningen, Groningen, The Netherlands
| | - J L Aris-Meijer
- Department of Epidemiology, University Medical Center Groningen, University of Groningen, PO Box 30.001, FA 40, 9700, RB, Groningen, The Netherlands
| | - R P Stolk
- Department of Epidemiology, University Medical Center Groningen, University of Groningen, PO Box 30.001, FA 40, 9700, RB, Groningen, The Netherlands
| | - S Otten
- Department of Social Psychology, Faculty of Behavioral and Social Sciences, University of Groningen, Groningen, The Netherlands
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Venema E, Otten S, Vlaskamp C. The efforts of direct support professionals to facilitate inclusion: the role of psychological determinants and work setting. J Intellect Disabil Res 2015; 59:970-979. [PMID: 26190561 DOI: 10.1111/jir.12209] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 06/10/2015] [Accepted: 06/24/2015] [Indexed: 06/04/2023]
Abstract
BACKGROUND Various studies have found that direct support professionals (DSPs) play an important role in determining the degree to which people with intellectual disabilities (ID) are included in society. However, less research has been conducted on the psychological processes that may influence the behavioural intentions of DSPs to actually engage with and invest effort in supporting their clients' inclusion. Five possible psychological variables are identified in the literature: attitudes, social norms, experienced competencies, identity and meta-evaluation. In our research, we tested whether these processes influence the (intended) efforts DSPs make to facilitate their clients' inclusion. METHOD A structured questionnaire was sent to 927 DSPs working in one of three different locations (an ordinary non-segregated setting, a reversed non-segregated setting and a residential facility). Of these, 336 DSPs completed the questionnaire. RESULTS Several variables revealed differences between the three locations, specifically in efforts to facilitate inclusion, attitudes, social norms, experienced competencies and professional identity. Looking at the overall means, we found (relatively) high scores for the experienced competencies, role identity and meta-evaluation. In contrast, the means were relatively negative regarding the DSPs' attitudes to inclusion and their assumed social norms. CONCLUSIONS Direct support professionals' efforts to facilitate inclusion depend on their attitude towards inclusion, the experienced competencies, their role identity, the DSPs' meta-evaluation and, indirectly through attitudes, also on the assumed social norms of the relevant stakeholders. Organizations responsible for supporting people with ID and which may want their DSPs to make greater efforts to facilitate inclusion should pay attention to these psychological variables.
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Affiliation(s)
- E Venema
- Department of Special Needs Education and Child Care, Faculty of Behavioral and Social Sciences, University of Groningen, Groningen, The Netherlands
| | - S Otten
- Department of Social Psychology, Faculty of Behavioral and Social Sciences, University of Groningen, Groningen, The Netherlands
| | - C Vlaskamp
- Department of Special Needs Education and Child Care, Faculty of Behavioral and Social Sciences, University of Groningen, Groningen, The Netherlands
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Klinkhammer BM, Kramann R, Mallau M, Makowska A, van Roeyen CR, Rong S, Buecher EB, Boor P, Kovacova K, Zok S, Denecke B, Stuettgen E, Otten S, Floege J, Kunter U. Mesenchymal stem cells from rats with chronic kidney disease exhibit premature senescence and loss of regenerative potential. PLoS One 2014; 9:e92115. [PMID: 24667162 PMCID: PMC3965415 DOI: 10.1371/journal.pone.0092115] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 02/17/2014] [Indexed: 12/14/2022] Open
Abstract
Mesenchymal stem cell (MSC) transplantation has the potential for organ repair. Nevertheless, some factors might lessen the regenerative potential of MSCs, e.g. donor age or systemic disease. It is thus important to carefully assess the patient's suitability for autologous MSC transplantation. Here we investigated the effects of chronic kidney disease (CKD) on MSC function. We isolated bone marrow MSCs from remnant kidney rats (RK) with CKD (CKD-RK-MSC) and found signs of premature senescence: spontaneous adipogenesis, reduced proliferation capacity, active senescence-associated-β-galactosidase, accumulation of actin and a modulated secretion profile. The functionality of CKD-RK-MSCs in vivo was tested in rats with acute anti-Thy1.1-nephritis, where healthy MSCs have been shown to be beneficial. Rats received healthy MSCs, CKD-RK-MSC or medium by injection into the left renal artery. Kidneys receiving healthy MSCs exhibited accelerated healing of glomerular lesions, whereas CKD-RK-MSC or medium exerted no benefit. The negative influence of advanced CKD/uremia on MSCs was confirmed in a second model of CKD, adenine nephropathy (AD). MSCs from rats with adenine nephropathy (CKD-AD-MSC) also exhibited cellular modifications and functional deficits in vivo. We conclude that CKD leads to a sustained loss of in vitro and in vivo functionality in MSCs, possibly due to premature cellular senescence. Considering autologous MSC therapy in human renal disease, studies identifying uremia-associated mechanisms that account for altered MSC function are urgently needed.
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Affiliation(s)
| | - Rafael Kramann
- Division of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Monika Mallau
- Division of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Anna Makowska
- Division of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | | | - Song Rong
- Division of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Eva Bettina Buecher
- Division of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Peter Boor
- Division of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany
- Institute of Pathology, RWTH Aachen University Hospital, Aachen, Germany
- Institute of Molecular Biomedicine, Comenius University, Bratislava, Slovakia
| | - Katarina Kovacova
- Division of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Stephanie Zok
- Division of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Bernd Denecke
- Interdisciplinary Centre for Clinical Research, RWTH Aachen University Hospital, Aachen, Germany
| | - Esther Stuettgen
- Division of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Simon Otten
- Division of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Juergen Floege
- Division of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Uta Kunter
- Division of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany
- * E-mail:
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9
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Becker M, Altiok E, Lente C, Otten S, Friedman Z, Adam D, Hoffmann R, Koos R, Krombach G, Marx N, Hoffmann R. Layer-specific analysis of myocardial function for accurate prediction of reversible ischaemic dysfunction in intermediate viability defined by contrast-enhanced MRI. Heart 2011; 97:748-56. [DOI: 10.1136/hrt.2010.210906] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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Okken VS, Niemeijer MG, Dijkstra A, Baars MW, Said S, Hoogenberg K, Orfgen H, Otten S, Cleophas TJ. The effect of physical, social and psychological factors on drug compliance in patients with mild hypertension. Neth Heart J 2008; 16:197-200. [PMID: 18665204 PMCID: PMC2442662 DOI: 10.1007/bf03086145] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [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: 10/19/2022] Open
Abstract
BACKGROUND In patients with hypertension noncompliance with drug treatment is between 15 to 54%, and has been recognised as a relevant contributor to the burden of cardiovascular morbidity. Up to 92% of patients experience unpleasant symptoms with their condition and, particularly in these patients, the symptoms experienced may enhance compliance. OBJECTIVE To simultaneously assess the effects of physical, social and psychological factors on noncompliance. METHODS Patients with mild hypertension despite drug treatment, from the departments of cardiology and internal medicine, were requested to answer a self-administered questionnaire addressing the presence of physical symptoms as well as psychosocial factors. The questionnaire was based on previously used test batteries and consisted of two lists of physical complaints and four lists addressing the four domains of planned behaviour regarding medical non-adherence according to Baron and Byrne. These domains mainly assess psychosocial factors. Each list consisted of three or more items and each item was scored on fiveto seven-point scales. Mean scores were used for assessment. The lists were also separately assessed for internal consistency and reliability using Cronbach's alphas. One-way analysis of variance and multivariate analysis of variance (MANOVA) with compliance as outcome variable and the physical, social and psychological variables as indicator variables were used for data analysis. MANOVA was adjusted for multiple testing. RESULTS Many patients experienced physical symptoms due to hypertension, such as tiredness (31%), hot flushes (28%), headache (24%), reduced daily life energy (23%), palpitations (22%), with 95% confidence intervals between 16 to 38%. Scores for physical symptoms and social factors did not differ between self-reported adherers (n=165) and nonadherers (n=11). However, the score for psychological factors was significantly larger in the adherers than in the non-adherers, 5.05 versus 3.06, p<0.018. The MANOVA showed a significant overall difference between the adherers and non-adherers in the data at p<0.012, which was mainly due to the score for psychological factors. Conclusion. The effect of physical symptoms on non-compliance in mildly hypertensive patients is negligible. So is the effect of social factors. Psychological factors such as lacking a sense of guilt, regret and shame are major determinants of non-compliance. Physicians may play an educational role in improving their patients' compliance by addressing these determinants. We should add that the conclusions should be made with reservations, given the small number of non-adherers in our sample. (Neth Heart J 2008;16:197-200.).
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Affiliation(s)
- V S Okken
- Department of Social and Organisational Psychology, University of Groningen, Groningen, the Netherlands
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Ziegler K, Görl R, Effing J, Ellermann J, Mappes M, Otten S, Kapp H, Zoellner P, Spaeth D, Smola H. Reduced Cellular Toxicity of a New Silver-Containing Antimicrobial Dressing and Clinical Performance in Non-Healing Wounds. Skin Pharmacol Physiol 2006; 19:140-6. [PMID: 16612141 DOI: 10.1159/000092594] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2005] [Accepted: 07/21/2005] [Indexed: 11/19/2022]
Abstract
Bacterial colonisation of wounds may delay wound healing. Modern silver-containing dressings are antimicrobial, yet cellular toxicity is a serious side-effect. We provide data for a newly formulated silver-containing ointment dressing, Atrauman Ag, for antimicrobial activity and cytotoxicity. Atrauman Ag effectively killed a panel of commensal skin as well as pathogenic bacterial strains while cytotoxicity for HaCaT keratinocytes was only around 10%. With these favourable in vitro tests, Atrauman Ag was analysed in 86 patients with traumatic and non-healing wounds of different aetiologies. The wound state was evaluated for 3 subsequent dressing changes. The slough score was reduced from 59.2 to 35.8%, granulation tissue increased from 27 to 40% and epithelialisation went up from 12.1 to 24%. We conclude that Atrauman Ag has a superior profile of antimicrobial activity over cellular toxicity and the low silver ion release rate may prevent interference with wound-healing mechanisms.
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Affiliation(s)
- K Ziegler
- Paul Hartmann AG, Heidenheim, Germany
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Abstract
The relationship between tRNA structure and function has been widely investigated by site-directed mutagenesis. This method has been a very useful tool to reveal the critical bases in tRNAs that are important for recognition and aminoacylation, but has been limited by the large number of possible base combinations in tRNA molecules. We have devised a new method that uses tRNA knockout cells for selection of functional tRNAs from a mutant tRNA gene library to overcome this limitation. To explore the mechanism of tRNA(Ala) recognition, the bases of the acceptor-stem region were randomized and active mutants were selected in a tRNA(Ala) knockout strain. Mutants of tRNA(Ala) having diverse sequence combinations in the acceptor-stem region and a broad range of functional activity to support knockout cell growth were isolated. The mutant tRNAs selected by the method included molecules containing novel base substitutions as well as extensively altered base combinations that would not be readily generated by rationally designed site-directed mutagenesis. Our results emphasize the importance of the acceptor stem as a structural unit in which some nucleotides may carry more weight than others, but in summation every nucleotide contributes to the interaction with the enzyme.
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Affiliation(s)
- H Choi
- Department of Bacteriology, University of Wisconsin, WI Madison 53706-1567, USA
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Machner MP, Urbanke C, Barzik M, Otten S, Sechi AS, Wehland J, Heinz DW. ActA from Listeria monocytogenes can interact with up to four Ena/VASP homology 1 domains simultaneously. J Biol Chem 2001; 276:40096-103. [PMID: 11489888 DOI: 10.1074/jbc.m104279200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The facultative intracellular human pathogenic bacterium Listeria monocytogenes actively recruits host actin to its surface to achieve motility within infected cells. The bacterial surface protein ActA is solely responsible for this process by mimicking fundamental steps of host cell actin dynamics. ActA, a modular protein, contains an N-terminal actin nucleation site and a central proline-rich motif of the 4-fold repeated consensus sequence FPPPP (FP(4)). This motif is specifically recognized by members of the Ena/VASP protein family. These proteins additionally recruit the profilin-G-actin complex increasing the local concentration of G-actin close to the bacterial surface. By using analytical ultracentrifugation, we show that a single ActA molecule can simultaneously interact with four Ena/VASP homology 1 (EVH1) domains. The four FP(4) sites have roughly equivalent affinities with dissociation constants of about 4 microm. Mutational analysis of the FP(4) motifs indicate that the phenylalanine is mandatory for ActA-EVH1 interaction, whereas in each case exchange of the third proline was tolerated. Finally, by using sedimentation equilibrium centrifugation techniques, we demonstrate that ActA is a monomeric protein. By combining these results, we formulate a stoichiometric model to describe how ActA enables Listeria to utilize efficiently resources of the host cell microfilament for its own intracellular motility.
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Affiliation(s)
- M P Machner
- Department of Structural Biology, German Research Center for Biotechnology (GBF), Mascheroder Weg 1, D-38124 Braunschweig, Germany
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Abstract
Listeria monocytogenes is a facultative intracellular pathogen responsible for both invasive and non-invasive food-borne illness in animals and humans. In this study, macrorestriction analysis following pulsed-field gel electrophoresis was used to show that Listeria monocytogenes serovar 1/2a strain EGD has a single chromosome containing eight NotI fragments of 1100, 850, 365, 320, 275, 40, 30 and 20 kb in size and 11 AscI fragments of 860, 470, 410, 360, 320, 250, 110, 80, 50, 30 and 20 kb. The total genome therefore comprises 3000 +/- 50 kb. The creation of a physical and genetic map of the Listeria genome was achieved by generating NotI linking clones and their use in subsequent hybridisation analysis. Using isogenic mutants harbouring additional artificial NotI restriction sites, we were able to precisely map the positions of all currently known virulence genes on the chromosome.
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Affiliation(s)
- U von Both
- Institut für Medizinische Mikrobiologie, Justus-Liebig-Universität, Giessen, Germany.
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Abstract
Serospecific antigens isolated by EDTA extraction from four serogroups of Legionella pneumophila were analyzed for their chemical composition, molecular heterogeneity by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and immunological properties. The antigens were shown to be lipopolysaccharides and to differ from the lipopolysaccharides of other gram-negative bacteria. The serospecific antigens contained rhamnose, mannose, glucosamine, and two unidentified sugars together with 2-keto-3-deoxyoctonate, phosphate, and fatty acids. The fatty acid composition was predominantly branched-chain acids with smaller amounts of 3-hydroxymyristic acid. The antigens contain periodate-sensitive groups; mannosyl residues were completely cleaved by periodate oxidation. Hydrolysis of the total lipopolysaccharide by acetic acid resulted in the separation of a lipid A-like material that cross-reacted with the antiserum to lipid A from Salmonella minnesota but did not comigrate with it on sodium dodecyl sulfate gels. None of the four antigens contained heptose. All of the antigen preparations showed endotoxicity when tested by the Limulus amebocyte lysate assay. The results of this study indicate that the serogroup-specific antigens of L. pneumophila are lipopolysaccharides containing an unusual lipid A and core structure and different from those of other gram-negative bacteria.
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Otten S, Rosazza JP. Microbial transformations of natural antitumor agents: conversion of lapachol to dehydro-alpha-lapachone by Curvularia lunata. Appl Environ Microbiol 1979; 38:311-3. [PMID: 574750 PMCID: PMC243482 DOI: 10.1128/aem.38.2.311-313.1979] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Microbial transformation of lapachol, a naturally occurring naphthoquinone, was carried out by Curvularia lunata (NRRL 2178). The fungus brings about oxidative cyclization of the substrate to dehydro-alpha-lapachone, which was isolated and characterized by nuclear magnetic resonance and mass spectral analyses; its structure was verified by chemical synthesis. The metabolite is a naturally occurring chromene possessing antibacterial and antitumor activities.
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Abstract
The naphthoquinone lapachol (1) is readily metabolized by several fungi and streptomycetes. Preparative-scale fermentations with Penicillium notatum (UI 1602) provided a major polar metabolite (4), which was isolated and identified as an intermediate of the Hooker oxidation. The metabolite was synthesized by reacting lapachol with hydrogen peroxide under alkaline conditions.
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