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Luka B, Duerrschnabel A, Neumaier S, Schlueter N, Vach K. Interaction between Hexametaphosphate, Other Active Ingredients of Toothpastes, and Erosion-Abrasion in Enamel in vitro. Caries Res 2023; 57:265-275. [PMID: 37725923 PMCID: PMC10641800 DOI: 10.1159/000534057] [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: 03/15/2023] [Accepted: 09/06/2023] [Indexed: 09/21/2023] Open
Abstract
Sodium hexametaphosphate (HMP) as toothpaste additive is claimed to reduce erosive tooth wear and to stabilize stannous ions. However, little is known about the impact of concentration and its interactions with fluoride (F) or stannous+fluoride ions (F/Sn) on enamel erosion and erosion-abrasion. In a 10 day cyclic in vitro erosion-abrasion model, 320 flat human enamel specimens were divided into ten groups (n = 32 each) and daily subjected to six erosive challenges (0.5% citric acid, 2 min) and two toothpaste suspension applications (2 min, 1:3 F-free toothpaste:mineral-salt solution, 0.23% sodium gluconate). Half of specimens per group were additionally brushed twice/day (200 g, 15 s) during suspension immersion. Nine suspensions contained HMP (0.25%, 1.75%, 3.25%), either on its own or combined with F (373 ppm F-) or F/Sn (800 ppm Sn2+, 373 ppm F-). One suspension contained sodium gluconate only (NegContr). After 10 days, specimens' surfaces were analysed with profilometry, energy dispersive X-ray spectroscopy, and scanning electron microscopy. Tissue loss (µm, mean ± standard deviation) in NegContr was 10.9 ± 2.0 (erosion), 22.2 ± 1.6 (erosion-abrasion). Under erosive conditions, only 0.25% HMP in any combination and 1.75% HMP with F/Sn reduced loss significantly (-28% to -54%); 3.25% HMP without F and F/Sn increased loss significantly (+35%). With additional abrasion, no suspension reduced loss significantly compared to NegContr, instead, in groups without F and F/Sn or with 3.25% HMP loss was increased (+15% to +30%). Conclusively, at higher concentrations, HMP increased erosive tooth wear and seemed to reduce anti-erosive effects of fluoride and stannous ions.
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Affiliation(s)
- Benedikt Luka
- Hannover Medical School (MHH), Department of Conservative Dentistry, Periodontology and Preventive Dentistry, Hannover, Germany
| | - Andrea Duerrschnabel
- Division for Cariology, Department of Operative Dentistry and Periodontology, Center for Dental Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Sina Neumaier
- Division for Cariology, Department of Operative Dentistry and Periodontology, Center for Dental Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Nadine Schlueter
- Hannover Medical School (MHH), Department of Conservative Dentistry, Periodontology and Preventive Dentistry, Hannover, Germany
| | - Kirstin Vach
- Hannover Medical School (MHH), Department of Conservative Dentistry, Periodontology and Preventive Dentistry, Hannover, Germany
- Department of Operative Dentistry and Periodontology, Center for Dental Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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Subedi P, Huber K, Sterr C, Dietz A, Strasser L, Kaestle F, Hauck SM, Duchrow L, Aldrian C, Monroy Ordonez EB, Luka B, Thomsen AR, Henke M, Gomolka M, Rößler U, Azimzadeh O, Moertl S, Hornhardt S. Towards unravelling biological mechanisms behind radiation-induced oral mucositis via mass spectrometry-based proteomics. Front Oncol 2023; 13:1180642. [PMID: 37384298 PMCID: PMC10298177 DOI: 10.3389/fonc.2023.1180642] [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] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 05/22/2023] [Indexed: 06/30/2023] Open
Abstract
Objective Head and neck cancer (HNC) accounts for almost 890,000 new cases per year. Radiotherapy (RT) is used to treat the majority of these patients. A common side-effect of RT is the onset of oral mucositis, which decreases the quality of life and represents the major dose-limiting factor in RT. To understand the origin of oral mucositis, the biological mechanisms post-ionizing radiation (IR) need to be clarified. Such knowledge is valuable to develop new treatment targets for oral mucositis and markers for the early identification of "at-risk" patients. Methods Primary keratinocytes from healthy volunteers were biopsied, irradiated in vitro (0 and 6 Gy), and subjected to mass spectrometry-based analyses 96 h after irradiation. Web-based tools were used to predict triggered biological pathways. The results were validated in the OKF6 cell culture model. Immunoblotting and mRNA validation was performed and cytokines present in cell culture media post-IR were quantified. Results Mass spectrometry-based proteomics identified 5879 proteins in primary keratinocytes and 4597 proteins in OKF6 cells. Amongst them, 212 proteins in primary keratinocytes and 169 proteins in OKF6 cells were differentially abundant 96 h after 6 Gy irradiation compared to sham-irradiated controls. In silico pathway enrichment analysis predicted interferon (IFN) response and DNA strand elongation pathways as mostly affected pathways in both cell systems. Immunoblot validations showed a decrease in minichromosome maintenance (MCM) complex proteins 2-7 and an increase in IFN-associated proteins STAT1 and ISG15. In line with affected IFN signalling, mRNA levels of IFNβ and interleukin 6 (IL-6) increased significantly following irradiation and also levels of secreted IL-1β, IL-6, IP-10, and ISG15 were elevated. Conclusion This study has investigated biological mechanisms in keratinocytes post-in vitro ionizing radiation. A common radiation signature in keratinocytes was identified. The role of IFN response in keratinocytes along with increased levels of pro-inflammatory cytokines and proteins could hint towards a possible mechanism for oral mucositis.
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Affiliation(s)
- Prabal Subedi
- Bundesamt für Strahlenschutz/Federal Office for Radiation Protection, Neuherberg, Germany
| | - Katharina Huber
- Bundesamt für Strahlenschutz/Federal Office for Radiation Protection, Neuherberg, Germany
| | - Christoph Sterr
- Bundesamt für Strahlenschutz/Federal Office for Radiation Protection, Neuherberg, Germany
| | - Anne Dietz
- Bundesamt für Strahlenschutz/Federal Office for Radiation Protection, Neuherberg, Germany
| | - Lukas Strasser
- Bundesamt für Strahlenschutz/Federal Office for Radiation Protection, Neuherberg, Germany
| | - Felix Kaestle
- Bundesamt für Strahlenschutz/Federal Office for Radiation Protection, Neuherberg, Germany
| | - Stefanie M. Hauck
- Helmholtz Zentrum München, German Research Centre for Environmental Health, Metabolomics and Proteomics Core, Munich, Germany
| | - Lukas Duchrow
- Bundesamt für Strahlenschutz/Federal Office for Radiation Protection, Neuherberg, Germany
| | - Christine Aldrian
- Department of Radiation Oncology, Medical Center, Faculty of Medicine, University of Freiburg, German Cancer Consortium (DKTK) partner site Freiburg, Freiburg, Germany
| | - Elsa Beatriz Monroy Ordonez
- Department of Radiation Oncology, Medical Center, Faculty of Medicine, University of Freiburg, German Cancer Consortium (DKTK) partner site Freiburg, Freiburg, Germany
| | - Benedikt Luka
- Department of Conservative Dentistry Periodontology and Preventive Dentistry, Hannover Medical School (MHH), Hannover, Germany
| | - Andreas R. Thomsen
- Department of Radiation Oncology, Medical Center, Faculty of Medicine, University of Freiburg, German Cancer Consortium (DKTK) partner site Freiburg, Freiburg, Germany
- German Cancer Consortium (DKTK) Partner Site Freiburg, German Cancer Research Center (dkfz), Heidelberg, Germany
| | - Michael Henke
- Department of Radiation Oncology, Medical Center, Faculty of Medicine, University of Freiburg, German Cancer Consortium (DKTK) partner site Freiburg, Freiburg, Germany
- German Cancer Consortium (DKTK) Partner Site Freiburg, German Cancer Research Center (dkfz), Heidelberg, Germany
| | - Maria Gomolka
- Bundesamt für Strahlenschutz/Federal Office for Radiation Protection, Neuherberg, Germany
| | - Ute Rößler
- Bundesamt für Strahlenschutz/Federal Office for Radiation Protection, Neuherberg, Germany
| | - Omid Azimzadeh
- Bundesamt für Strahlenschutz/Federal Office for Radiation Protection, Neuherberg, Germany
| | - Simone Moertl
- Bundesamt für Strahlenschutz/Federal Office for Radiation Protection, Neuherberg, Germany
| | - Sabine Hornhardt
- Bundesamt für Strahlenschutz/Federal Office for Radiation Protection, Neuherberg, Germany
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Thomsen A, Aldrian C, Luka B, Hornhardt S, Gomolka M, Moertl S, Hess J, Zitzelsberger H, Heider T, Schlueter N, Rau S, Monroy Ordonez B, Schäfer H, Rücker G, Henke M. Biopsy-Derived Oral Keratinocytes – a Model to Potentially Test for Oral Mucosa Radiation Sensitivity. Clin Transl Radiat Oncol 2022; 34:51-56. [PMID: 35345866 PMCID: PMC8956846 DOI: 10.1016/j.ctro.2022.03.007] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/13/2022] [Accepted: 03/14/2022] [Indexed: 11/29/2022] Open
Abstract
Human oral keratinocytes – the key players in radiation mucositis in head and neck cancer treatment – are established ex vivo from patient-derived micro-biopsies. Individual radiosensitivity of primary oral keratinocytes is measured by a novel assay for cellular proliferation and spreading. The keratinocyte model also supports classical functional assays such as clonogenic survival and DNA double strand repair.
Purpose To establish stable in vitro growth of keratinocytes from very small biopsy specimens and successfully apply new test systems to determine their radiosensitivity. Materials and Methods Oral mucosa biopsies (diameter: 1.7 mm) from 15 subjects were immobilized with custom-made cups onto culture plates. Outgrowing cells were tested for cytokeratin 5/14 and Ki67, expanded, radiated at different doses, and seeded onto circumscribed areas before being allowed to spread centrifugally. In this newly developed spreading assay, cell-covered areas were measured by image analysis. For statistical analysis, a linear mixed regression model was used; additionally, results were correlated to the radiation dose applied. Colony forming efficiency (CFE) was used to validate the results. DNA damage repair was analysed by gammaH2AX and 53BP1 foci quantification using immunofluorescence microscopy 24 h and 96 h after irradiation. Results Stable keratinocyte growth continued for up to 7 weeks in 14 biopsies. Cells spread reliably from an initial 16.6 mm2 up to a median of 119.2 mm2 (range: 54.4–290). Radiated cells spread to only 100.7 mm2 (2 Gy; range: 55.3–266.7); 73.2 mm2 (4 Gy; 15–240.4); 47 mm2 (6 Gy; 2–111.9), and 22.7 mm2 (8 Gy; 0–80). Similarly, CFE decreased from 0.223 (0 Gy) to 0.0028 (8 Gy). Using an individual donor as a random factor, cell spread correlated with CFE, where radiation dose was the main driver (decrease by 0.50, adjusted for area). Upon irradiation with 6 Gy, radiation-induced DNA damage was increased after 24 h in all samples, and even after 96 h in 5 out of 7 samples, as detected by a higher number of gammaH2AX/53BP1 foci in irradiated cells (mean 3.7 for 24 h; mean 0.6 for 96 h). Conclusion In vitro propagation of keratinocytes derived from a small biopsy is feasible. Radiation impairs cellular migration and proliferation, and the newly described spreading assay allows ranking for cellular radioresistance. The keratinocyte model also supports classical functional assays such as clonogenic survival and DNA double strand repair. The clinical relevance awaits upcoming investigations.
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Affiliation(s)
- A.R. Thomsen
- Department of Radiation Oncology, University Medical Center, University of Freiburg, Freiburg/Breisgau, Germany
- German Cancer Consortium (DKTK) Partner Site Freiburg, German Cancer Research Center (dkfz), Heidelberg, Germany
- Corresponding author at: Department of Radiation Oncology, University Medical Center, University of Freiburg, Freiburg/Breisgau, Germany.
| | - C. Aldrian
- Department of Radiation Oncology, University Medical Center, University of Freiburg, Freiburg/Breisgau, Germany
- German Cancer Consortium (DKTK) Partner Site Freiburg, German Cancer Research Center (dkfz), Heidelberg, Germany
| | - B. Luka
- Division for Cariology, Department of Operative Dentistry and Periodontology, Center for Dental Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - S. Hornhardt
- Federal Office for Radiation Protection, Ingolstädter Landstr. 1, 85764 Oberschleißheim, Germany
| | - M. Gomolka
- Federal Office for Radiation Protection, Ingolstädter Landstr. 1, 85764 Oberschleißheim, Germany
| | - S. Moertl
- Federal Office for Radiation Protection, Ingolstädter Landstr. 1, 85764 Oberschleißheim, Germany
| | - J. Hess
- Research Unit Radiation Cytogenetics, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Neuherberg, Germany
- Clinical Cooperation Group “Personalized Radiotherapy in Head and Neck Cancer”, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Neuherberg, Germany
- Department of Radiation Oncology, University Hospital, LMU Munich, Munich, Germany
| | - H. Zitzelsberger
- Research Unit Radiation Cytogenetics, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Neuherberg, Germany
| | - T. Heider
- Department of Radiation Oncology, University Hospital, LMU Munich, Munich, Germany
| | - N. Schlueter
- Division for Cariology, Department of Operative Dentistry and Periodontology, Center for Dental Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - S. Rau
- Division for Cariology, Department of Operative Dentistry and Periodontology, Center for Dental Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - B. Monroy Ordonez
- Department of Radiation Oncology, University Medical Center, University of Freiburg, Freiburg/Breisgau, Germany
- German Cancer Consortium (DKTK) Partner Site Freiburg, German Cancer Research Center (dkfz), Heidelberg, Germany
| | - H. Schäfer
- Department of Radiation Oncology, University Medical Center, University of Freiburg, Freiburg/Breisgau, Germany
- German Cancer Consortium (DKTK) Partner Site Freiburg, German Cancer Research Center (dkfz), Heidelberg, Germany
| | - G. Rücker
- Institute for Medical Biometry and Statistics, Medical Center – University of Freiburg, Germany
| | - M. Henke
- Department of Radiation Oncology, University Medical Center, University of Freiburg, Freiburg/Breisgau, Germany
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Schoetz U, Klein D, Hess J, Shnayien S, Spoerl S, Orth M, Mutlu S, Hennel R, Sieber A, Ganswindt U, Luka B, Thomsen AR, Unger K, Jendrossek V, Zitzelsberger H, Blüthgen N, Belka C, Unkel S, Klinger B, Lauber K. Early senescence and production of senescence-associated cytokines are major determinants of radioresistance in head-and-neck squamous cell carcinoma. Cell Death Dis 2021; 12:1162. [PMID: 34911941 PMCID: PMC8674332 DOI: 10.1038/s41419-021-04454-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [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: 06/11/2021] [Revised: 11/12/2021] [Accepted: 11/30/2021] [Indexed: 12/18/2022]
Abstract
Resistance against radio(chemo)therapy-induced cell death is a major determinant of oncological treatment failure and remains a perpetual clinical challenge. The underlying mechanisms are manifold and demand for comprehensive, cancer entity- and subtype-specific examination. In the present study, resistance against radiotherapy was systematically assessed in a panel of human head-and-neck squamous cell carcinoma (HNSCC) cell lines and xenotransplants derived thereof with the overarching aim to extract master regulators and potential candidates for mechanism-based pharmacological targeting. Clonogenic survival data were integrated with molecular and functional data on DNA damage repair and different cell fate decisions. A positive correlation between radioresistance and early induction of HNSCC cell senescence accompanied by NF-κB-dependent production of distinct senescence-associated cytokines, particularly ligands of the CXCR2 chemokine receptor, was identified. Time-lapse microscopy and medium transfer experiments disclosed the non-cell autonomous, paracrine nature of these mechanisms, and pharmacological interference with senescence-associated cytokine production by the NF-κB inhibitor metformin significantly improved radiotherapeutic performance in vitro and in vivo. With regard to clinical relevance, retrospective analyses of TCGA HNSCC data and an in-house HNSCC cohort revealed that elevated expression of CXCR2 and/or its ligands are associated with impaired treatment outcome. Collectively, our study identifies radiation-induced tumor cell senescence and the NF-κB-dependent production of distinct senescence-associated cytokines as critical drivers of radioresistance in HNSCC whose therapeutic targeting in the context of multi-modality treatment approaches should be further examined and may be of particular interest for the subgroup of patients with elevated expression of the CXCR2/ligand axis.
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Affiliation(s)
- Ulrike Schoetz
- Department of Radiation Oncology, University Hospital, LMU München, Munich, Germany.,Department of Radiotherapy and Radiooncology, Philipps-University Marburg, University Hospital Gießen and Marburg, Marburg, Germany
| | - Diana Klein
- Institute of Cell Biology (Cancer Research), University of Duisburg-Essen, University Hospital, Essen, Germany
| | - Julia Hess
- Research Unit Radiation Cytogenetics, Helmholtz Center Munich, German Research Center for Environmental Health GmbH, Neuherberg, Germany.,Clinical Cooperation Group 'Personalized Radiotherapy in Head and Neck Cancer' Helmholtz Center Munich, German Research Center for Environmental Health GmbH, Neuherberg, Germany
| | - Seyd Shnayien
- Department of Radiation Oncology, University Hospital, LMU München, Munich, Germany
| | - Steffen Spoerl
- Department of Radiation Oncology, University Hospital, LMU München, Munich, Germany
| | - Michael Orth
- Department of Radiation Oncology, University Hospital, LMU München, Munich, Germany
| | - Samet Mutlu
- Department of Radiation Oncology, University Hospital, LMU München, Munich, Germany.,German Cancer Consortium (DKTK), Partner site Munich, Munich, Germany.,German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Roman Hennel
- Department of Radiation Oncology, University Hospital, LMU München, Munich, Germany
| | - Anja Sieber
- Institute of Pathology, Charite-Universitätsmedizin Berlin, Berlin, Germany.,IRI Life Sciences, Humboldt University of Berlin, Berlin, Germany
| | - Ute Ganswindt
- Department of Radiation Oncology, University Hospital, LMU München, Munich, Germany.,Department of Therapeutic Radiology and Oncology, Medical University of Innsbruck, Innsbruck, Austria
| | - Benedikt Luka
- Division for Cariology, Department of Operative Dentistry and Periodontology, Center for Dental Medicine, Medical Center - University of Freiburg, Freiburg im Breisgau, Germany
| | - Andreas R Thomsen
- Department of Radiation Oncology, Medical Center - University of Freiburg, Freiburg im Breisgau, Germany.,German Cancer Consortium (DKTK), Partner site Freiburg, Freiburg im Breisgau, Germany
| | - Kristian Unger
- Research Unit Radiation Cytogenetics, Helmholtz Center Munich, German Research Center for Environmental Health GmbH, Neuherberg, Germany.,Clinical Cooperation Group 'Personalized Radiotherapy in Head and Neck Cancer' Helmholtz Center Munich, German Research Center for Environmental Health GmbH, Neuherberg, Germany
| | - Verena Jendrossek
- Institute of Cell Biology (Cancer Research), University of Duisburg-Essen, University Hospital, Essen, Germany
| | - Horst Zitzelsberger
- Research Unit Radiation Cytogenetics, Helmholtz Center Munich, German Research Center for Environmental Health GmbH, Neuherberg, Germany.,Clinical Cooperation Group 'Personalized Radiotherapy in Head and Neck Cancer' Helmholtz Center Munich, German Research Center for Environmental Health GmbH, Neuherberg, Germany
| | - Nils Blüthgen
- Institute of Pathology, Charite-Universitätsmedizin Berlin, Berlin, Germany.,IRI Life Sciences, Humboldt University of Berlin, Berlin, Germany.,German Cancer Consortium (DKTK), Partner Site Berlin, Berlin, Germany
| | - Claus Belka
- Department of Radiation Oncology, University Hospital, LMU München, Munich, Germany.,Clinical Cooperation Group 'Personalized Radiotherapy in Head and Neck Cancer' Helmholtz Center Munich, German Research Center for Environmental Health GmbH, Neuherberg, Germany.,German Cancer Consortium (DKTK), Partner site Munich, Munich, Germany
| | - Steffen Unkel
- Department of Medical Statistics, University Medical Center Goettingen, Goettingen, Germany
| | - Bertram Klinger
- Institute of Pathology, Charite-Universitätsmedizin Berlin, Berlin, Germany.,IRI Life Sciences, Humboldt University of Berlin, Berlin, Germany.,German Cancer Consortium (DKTK), Partner Site Berlin, Berlin, Germany
| | - Kirsten Lauber
- Department of Radiation Oncology, University Hospital, LMU München, Munich, Germany. .,Clinical Cooperation Group 'Personalized Radiotherapy in Head and Neck Cancer' Helmholtz Center Munich, German Research Center for Environmental Health GmbH, Neuherberg, Germany. .,German Cancer Consortium (DKTK), Partner site Munich, Munich, Germany.
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Luka B, Arbter V, Sander K, Duerrschnabel A, Schlueter N. Impact of mucin on the anti-erosive/anti-abrasive efficacy of chitosan and/or F/Sn in enamel in vitro. Sci Rep 2021; 11:5285. [PMID: 33674643 PMCID: PMC7936000 DOI: 10.1038/s41598-021-84791-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [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: 09/25/2020] [Accepted: 02/17/2021] [Indexed: 11/09/2022] Open
Abstract
The application of stannous ions in combination with fluoride (F/Sn) is one of the central strategies in reducing erosive tooth wear. F/Sn efficacy can be enhanced by adding chitosan, a positively charged biopolymer. For patients with low saliva flow, this efficacy, however, is not sufficient, making further improvement desirable. This could be achieved by combining chitosan with other molecules like mucin, which together might form multilayers. This in-vitro study aimed to investigate the effect of chitosan, mucin, F/Sn and combinations thereof on enamel erosion and erosion-abrasion. Human enamel samples (n = 448, 28 groups) were cyclically eroded or eroded-abraded (10 days; 6 × 2 min erosion and 2 × 15 s/200 g abrasion per day). Samples were treated 2 × 2 min/day with solutions containing either, chitosan (50 or 500 mPas), porcine gastric mucin, F/Sn or combinations thereof after abrasive challenge. Tissue loss was measured profilometrically, interaction between hard tissue and active agents was assessed with energy dispersive spectroscopy and scanning electron microscopy. Chitosan and F/Sn showed the expected effect in reducing tissue loss under erosive and under erosive-abrasive conditions. Neither mucin alone nor the combinations with mucin showed any additional beneficial effect.
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Affiliation(s)
- Benedikt Luka
- Division for Cariology, Department of Operative Dentistry and Periodontology, Center for Dental Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany.
| | - Vivien Arbter
- Division for Cariology, Department of Operative Dentistry and Periodontology, Center for Dental Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany
| | - Kathrin Sander
- Division for Cariology, Department of Operative Dentistry and Periodontology, Center for Dental Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany
| | - Andrea Duerrschnabel
- Division for Cariology, Department of Operative Dentistry and Periodontology, Center for Dental Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany
| | - Nadine Schlueter
- Division for Cariology, Department of Operative Dentistry and Periodontology, Center for Dental Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany
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Pini NIP, Lima DANL, Luka B, Ganss C, Schlueter N. Viscosity of chitosan impacts the efficacy of F/Sn containing toothpastes against erosive/abrasive wear in enamel. J Dent 2020; 92:103247. [DOI: 10.1016/j.jdent.2019.103247] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 11/09/2019] [Accepted: 11/14/2019] [Indexed: 11/29/2022] Open
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Schlueter N, Luka B. Erosive tooth wear – a review on global prevalence and on its prevalence in risk groups. Br Dent J 2018; 224:364-370. [DOI: 10.1038/sj.bdj.2018.167] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2017] [Indexed: 11/09/2022]
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Schläfke ME, Zumfelde C, Luka B, Schäfer T, Greulich W. Control of breathing in patients with brainstem lesions. Akt Neurol 2007. [DOI: 10.1055/s-2007-987806] [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: 10/21/2022]
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Abstract
PURPOSE To determine the value of perfusion computed tomography (CT) in a clinical study of patients with stroke and compare the results with single photon emission CT (SPECT) findings. MATERIALS AND METHODS Perfusion CT was performed within 6 hours of symptom onset in 32 patients with possible stroke. Cerebral blood volume (CBV), cerebral blood flow (CBF), and time to peak contrast material enhancement were calculated on the basis of the CT results. Cerebral SPECT was also performed in a subgroup of 18 patients. Perfusion CT and SPECT findings were compared in a lesion-by-lesion analysis. Perfusion CT results were compared with follow-up CT and magnetic resonance imaging findings. RESULTS Areas of reduced CBF were detected with the aid of perfusion CT in 25 of 28 patients with a proved infarct (sensitivity, 89%). The results of the CBF maps corresponded well to SPECT findings in 13 (81%) of 16 patients, but ischemia was located outside the scanning level in the other three patients and was therefore missed. Perfusion CT revealed various changes in CBF, CBV, and time to peak enhancement in ischemic territories. CONCLUSION Perfusion CT not only allows early detection of cerebral ischemia but also yields valuable information about the extent of perfusion disturbances.
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Affiliation(s)
- M Koenig
- Department of Radiology, Ruhr-University Bochum, Germany
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Luka B, Brechtelsbauer D, Gellrich NC, König M. 2D and 3D CT reconstructions of the facial skeleton: an unnecessary option or a diagnostic pearl? Int J Oral Maxillofac Surg 1995; 24:76-83. [PMID: 7782648 DOI: 10.1016/s0901-5027(05)80866-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [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: 01/27/2023]
Abstract
The introduction of spiral computed tomography (CT) has been a major advance in CT scanning, particularly considering the reduction in acquisition time and improvements in 2-dimensional (2D) and 3D reconstructions. 314 out of 1262 CT examinations of the midface and jaws executed from September 1993 to September 1994 were performed in the spiral mode. Our experience is critically reviewed and a guideline for the use of spiral CT scanning of the midface and jaws for various diagnostic purposes is established: Complex midface fractures require axial spiral CT scanning with secondary coronal reconstructions Because of the long processing time 3D reconstructions are reserved for planning surgical repair of craniofacial malformations. Dental CT scans with calculation of panoramic images provide important information prior to dental implant surgery and repair of alveolar clefts.
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Affiliation(s)
- B Luka
- Department of Radiology and Nuclear Medicine, University Hospital, Knappschaftskrankenhaus, Bochum, Germany
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