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Foxton R, San Diego JP, Lu E, Rajadurai S, Bartlett A, McIlwane C, Austin R, Srisontisuk P, Sagoo AK, Piper K. Scaffolding competence-based learning design in the dental simulation curriculum. Eur J Dent Educ 2023. [PMID: 38147462 DOI: 10.1111/eje.12985] [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] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 10/10/2023] [Accepted: 11/21/2023] [Indexed: 12/28/2023]
Abstract
INTRODUCTION Learning in a clinical domain in dentistry is complex and learners may face uncertain clinical scenarios. A simulation curriculum can be designed to have simple clinical scenarios and learning activities which progress in complexity and employ competence assessments of simulated clinical practice before students can undertake authentic practice on patients. This paper presents how scaffolding of competence can be used for designing learning with simulators (haptics and phantom head) demonstrated in a specific domain in restorative dentistry. METHODS A collaborative workshop as a research approach was undertaken to inform the iterative analysis, development, and discussion on scaffolding the learning design with respect to competence assessments of learning cavity preparation with simulation-based learning technologies. A workshop was conducted, which was collaborative and involved design negotiations between researchers, technologists, and teachers/practitioners in developing the simulation curriculum. RESULTS A competence assessment with feedback in a specific domain in preparing interproximal caries was used as a context to describe how the learning activities and outcomes were designed to meet assessment of competence with varied levels of simple to complex learning activities and structured sessions. CONCLUSION Simulation curriculum can be designed and implemented by scaffolding the level of competence that can be learned using simulation between haptics and phantom-head. This brings impetus to the need in meeting the relevant competence criteria in context to a specific affordance of the simulation-based learning technologies to provide optimal patient-centred holistic care.
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Affiliation(s)
- Richard Foxton
- Centre for Dental Education, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, London, UK
| | - Jonathan P San Diego
- Centre for Dental Education, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, London, UK
| | - Emily Lu
- Centre for Dental Education, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, London, UK
| | - Susha Rajadurai
- Centre for Dental Education, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, London, UK
| | - Anitha Bartlett
- Centre for Dental Education, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, London, UK
| | - Clare McIlwane
- Centre for Dental Education, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, London, UK
| | - Rupert Austin
- Centre for Dental Education, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, London, UK
| | - Pinsuda Srisontisuk
- Centre for Dental Education, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, London, UK
| | - Anika K Sagoo
- Centre for Dental Education, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, London, UK
| | - Kim Piper
- Centre for Dental Education, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, London, UK
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Suzuki K, Iwata D, Namba K, Hase K, Hiraoka M, Murata M, Kitaichi N, Foxton R, Ishida S. Involvement of Angiopoietin 2 and vascular endothelial growth factor in uveitis. PLoS One 2023; 18:e0294745. [PMID: 38015876 PMCID: PMC10683998 DOI: 10.1371/journal.pone.0294745] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 11/08/2023] [Indexed: 11/30/2023] Open
Abstract
PURPOSE Angiopoietin (Ang) 2 is released from vascular endothelial cells by the stimulation of vascular endothelial growth factor (VEGF)A. Ang2 increases the expression of leukocyte adhesion molecules on endothelial cells via nuclear factor κB. The aim of this study was to evaluate the effects of Ang2 and VEGFA on ocular autoimmune inflammation. METHODS We measured the concentrations of Ang2 and VEGFA in vitreous samples among patients with uveitis. Vitreous samples were collected from 16 patients with idiopathic uveitis (uveitis group) and 16 patients with non-inflammatory eye disease (control group). Experimental autoimmune uveoretinitis (EAU) was induced in B10.BR mice with a human interphotoreceptor retinoid-binding protein-derived peptide. The retinochoroidal tissues of the EAU mice were removed, and the mRNA levels of Ang2 and VEGFA were examined. EAU mice treated with anti-Ang2, anti-VEGFA, a combination of anti-Ang2 and anti-VEGFA, anti-Ang2/VEGFA bispecific, or IgG control antibodies were clinically and histopathologically evaluated. RESULTS The protein levels of Ang2 and VEGFA were significantly higher in the vitreous samples of patients with uveitis than in controls (P<0.05). The retinochoroidal mRNA levels of Ang2 and VEGFA were significantly upregulated in EAU mice compared to controls (n = 6, P<0.05). Although there was no significant difference, treatment with anti-VEGFA antibody reduced the clinical and histopathological scores. However, treatment with anti-Ang2 antibody reduced the clinical and histopathological scores (n = 18-20, P<0.05). Furthermore, these scores were further decreased when treated by inhibiting both Ang2 and VEGFA. CONCLUSIONS Based on these results, VEGFA and Ang2 were shown to be upregulated locally in the eye of both uveitis patients and models of uveitis. Dual inhibition of Ang2 and VEGFA is suggested to be a new therapeutic strategy for uveitis.
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Affiliation(s)
- Kayo Suzuki
- Faculty of Medicine and Graduate School of Medicine, Department of Ophthalmology, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Daiju Iwata
- Faculty of Medicine and Graduate School of Medicine, Department of Ophthalmology, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Kenichi Namba
- Faculty of Medicine and Graduate School of Medicine, Department of Ophthalmology, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Keitaro Hase
- Faculty of Medicine and Graduate School of Medicine, Department of Ophthalmology, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Miki Hiraoka
- Department of Ophthalmology, Health Sciences University of Hokkaido, Sapporo, Hokkaido, Japan
| | - Miyuki Murata
- Faculty of Medicine and Graduate School of Medicine, Department of Ophthalmology, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Nobuyoshi Kitaichi
- Department of Ophthalmology, Health Sciences University of Hokkaido, Sapporo, Hokkaido, Japan
| | - Richard Foxton
- Roche Pharma Research and Early Development, Roche Innovation Center, Basel, Switzerland
| | - Susumu Ishida
- Faculty of Medicine and Graduate School of Medicine, Department of Ophthalmology, Hokkaido University, Sapporo, Hokkaido, Japan
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Hosaka K, Tichy A, Yamauti M, Watanabe K, Kamoi K, Yonekura K, Foxton R, Nakajima M. Digitally Guided Direct Composite Injection Technique with a Bi-layer Clear Mini-Index for the Management of Extensive Occlusal Caries in a Pediatric Patient: A Case Report. J Adhes Dent 2023; 25:211-218. [PMID: 37843503 DOI: 10.3290/j.jad.b4515527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
PURPOSE This case report presents a direct composite inverse injection technique using a bi-layer clear mini-index fabricated with a digital workflow to restore extensive posterior occlusal cavities in a 13-year-old patient. MATERIALS AND METHODS After a root canal treatment in the right mandibular first molar and step-wise excavation of deep caries in the left mandibular first molar, the extensive occlusal restorations were digitally designed using CAD software, upon which digital wax-ups were 3D-printed. Bi-layer clear mini-indices consisting of a hard outer plastic layer and an elastic inner silicone layer were prepared from the 3D-printed cast. The bonding surfaces were deproteinized using a 6% sodium hypochlorite solution, and an antioxidant (Clearfil DC Activator; Kuraray Noritake) was utilized to improve the dentin bonding durability of a 2-step self-etch adhesive (Clearfil SE Bond 2; Kuraray Noritake). Subsequently, a highly filled universal-shade flowable resin composite (RC) was incrementally placed into the cavities. To create the final occlusal morphology, the same RC was inversely injected through the opening of the bi-layer indices. RESULTS The workflow was feasible, and the occlusal cavities were efficiently restored using the injection technique. Occlusal carving and adjustments of the morphology were not necessary, leading to less chair time. At the 1-year follow-up, the clinical outcome was excellent. CONCLUSION The injection technique with a bi-layer clear mini-index accurately translated the digital wax-ups into large, final restorations. Precise morphology and shortened chair time enhanced patient satisfaction, but at the expense of multiple visits.
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ThanNaing S, Hiraishi N, Chen X, Foxton R, Shimada Y. In vitro remineralization assessment of enamel subsurface lesions using different percentages of surface reaction-type pre-reacted glass-ionomer containing gum-based material. J Dent 2023; 135:104602. [PMID: 37391026 DOI: 10.1016/j.jdent.2023.104602] [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: 03/25/2023] [Revised: 06/23/2023] [Accepted: 06/26/2023] [Indexed: 07/02/2023] Open
Abstract
OBJECTIVE To identify the remineralization activity of enamel subsurface lesions using different percentages of surface pre-reacted glass-ionomer (S-PRG) filler containing gum-base material. METHODS Gum extracts from gum-base materials containing 0wt%, 5wt%, and 10wt% S-PRG filler were prepared as GE0, GE5, and GE10, respectively. A total of 50 bovine enamel specimens were used, and the polished enamel surface of a 3 × 3 mm2 window area was exposed. The specimens were then subjected to a demineralization solution for seven days to create a subsurface enamel lesion. Remineralization was then conducted for seven days using a protocol whereby the specimens were immersed three times a day in prepared gum extracts (0wt%, 5wt%, and 10wt%) and artificial saliva of pH 7 (Control) for 20 min at 37 °C. Thereafter, remineralization assessment was performed by using Swept Source Optical Coherence Tomography (SS-OCT) and micro-computed tomography (μCT). Surface morphology and elemental analysis were conducted by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS). RESULTS The depths of the demineralized lesions in the GE5 and GE10 groups were significantly lower than those of the Control and the GE0 groups. SEM observations of the enamel surface morphology of the GE5 and GE10 groups indicated remineralization with S-PRG filler-related elements present. CONCLUSION The GE5 and GE10 S-PRG filler containing gum-base materials showed significantly improved surface remineralization and reduced demineralization of the enamel lesions. EDS analysis suggested that the released ions from the S-PRG filler might be responsible for surface remineralization. CLINICAL SIGNIFICANCE The S-PRG filler containing gum-base material may have a significant remineralization effect and improve the surface morphology of enamel subsurface lesions.
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Affiliation(s)
- SoeKayThwe ThanNaing
- Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45, Yushima, Bunkyo-Ku, Tokyo 113-8549, Japan; Department of Conservative Dentistry, University of Dental Medicine Mandalay, Chanmyathazi, Mandalay 05041, Myanmar
| | - Noriko Hiraishi
- Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45, Yushima, Bunkyo-Ku, Tokyo 113-8549, Japan.
| | - Xuefei Chen
- Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45, Yushima, Bunkyo-Ku, Tokyo 113-8549, Japan
| | - Richard Foxton
- Kings College London, Dental Institute, Guys Hospital, London, UK
| | - Yasushi Shimada
- Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45, Yushima, Bunkyo-Ku, Tokyo 113-8549, Japan
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Canonica J, Foxton R, Garrido MG, Lin CM, Uhles S, Shanmugam S, Antonetti DA, Abcouwer SF, Westenskow PD. Delineating effects of angiopoietin-2 inhibition on vascular permeability and inflammation in models of retinal neovascularization and ischemia/reperfusion. Front Cell Neurosci 2023; 17:1192464. [PMID: 37377777 PMCID: PMC10291265 DOI: 10.3389/fncel.2023.1192464] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [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: 03/23/2023] [Accepted: 05/26/2023] [Indexed: 06/29/2023] Open
Abstract
Introduction Clinical trials demonstrated that co-targeting angiopoietin-2 (Ang-2) and vascular endothelial growth factor (VEGF-A) with faricimab controls anatomic outcomes and maintains vision improvements, with strong durability, through 2 years in patients with neovascular age-related macular degeneration and diabetic macular edema. The mechanism(s) underlying these findings is incompletely understood and the specific role that Ang-2 inhibition plays requires further investigation. Methods We examined the effects of single and dual Ang-2/VEGF-A inhibition in diseased vasculatures of JR5558 mice with spontaneous choroidal neovascularization (CNV) and in mice with retinal ischemia/reperfusion (I/R) injuries. Results In JR5558 mice, Ang-2, VEGF-A, and dual Ang-2/VEGF-A inhibition reduced CNV area after 1 week; only dual Ang-2/VEGF-A inhibition decreased neovascular leakage. Only Ang-2 and dual Ang-2/VEGF-A inhibition maintained reductions after 5 weeks. Dual Ang-2/VEGF-A inhibition reduced macrophage/microglia accumulation around lesions after 1 week. Both Ang-2 and dual Ang-2/VEGF-A inhibition reduced macrophage/microglia accumulation around lesions after 5 weeks. In the retinal I/R injury model, dual Ang-2/VEGF-A inhibition was statistically significantly more effective than Ang-2 or VEGF-A inhibition alone in preventing retinal vascular leakage and neurodegeneration. Discussion These data highlight the role of Ang-2 in dual Ang-2/VEGF-A inhibition and indicate that dual inhibition has complementary anti-inflammatory and neuroprotective effects, suggesting a mechanism for the durability and efficacy of faricimab in clinical trials.
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Affiliation(s)
- Jérémie Canonica
- Roche Pharma Research and Early Development, Roche Innovation Center, Basel, Switzerland
| | - Richard Foxton
- Roche Pharma Research and Early Development, Roche Innovation Center, Basel, Switzerland
| | - Marina Garcia Garrido
- Roche Pharma Research and Early Development, Roche Innovation Center, Basel, Switzerland
| | - Cheng-Mao Lin
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan Medicine, Ann Arbor, MI, United States
| | - Sabine Uhles
- Roche Pharma Research and Early Development, Roche Innovation Center, Basel, Switzerland
| | - Sumathi Shanmugam
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan Medicine, Ann Arbor, MI, United States
| | - David A. Antonetti
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan Medicine, Ann Arbor, MI, United States
| | - Steven F. Abcouwer
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan Medicine, Ann Arbor, MI, United States
| | - Peter D. Westenskow
- Roche Pharma Research and Early Development, Roche Innovation Center, Basel, Switzerland
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Seki N, Sireerat K, Foxton R, Liao SR, Morio I. Critical thinking education for dental schools in Asia: Perceptions of educators. J Dent Sci 2023; 18:443-447. [PMID: 36643276 PMCID: PMC9831816 DOI: 10.1016/j.jds.2022.08.024] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/22/2022] [Indexed: 01/18/2023] Open
Abstract
Teaching competence in critical thinking is an important element of undergraduate dental curricula. The pedagogy for critical thinking education in Asia requires further discussion and neither the current situation nor the possible challenges are widely known from the perspectives of dental educators. Therefore, seven educators from four countries gathered online in the summer of 2021 to share the current situation and possible challenges. All the participants considered "critical thinking" was "important" (43%) or "very important" (57%), however, 86% mentioned that they faced challenges in delivering education in critical thinking. The challenges to delivering critical thinking education were insufficient time in the curriculum and lack of human resources; lack of information on appropriate teaching methods for the student population; and no established methods of assessment. How to teach and assess critical thinking therefore requires more brainstorming, and raising the awareness of educators to implement this education might be necessary.
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Affiliation(s)
- Naoko Seki
- Dental Education Development, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
- Institute of Global Affairs, Tokyo Medical and Dental University, Tokyo, Japan
- Corresponding author. Institute of Global Affairs, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan.
| | - Kittichai Sireerat
- Dental Education Development, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Richard Foxton
- Institute of Global Affairs, Tokyo Medical and Dental University, Tokyo, Japan
- Centre for Dental Education, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, London, UK
| | - Shin-Ru Liao
- Dental Education Development, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Ikuko Morio
- Dental Education Development, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
- Institute of Global Affairs, Tokyo Medical and Dental University, Tokyo, Japan
- Corresponding author. Institute of Global Affairs, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan.
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Canonica J, Shanmugam S, Lin C, Antonetti D, Foxton R, Uhles S, Westenkow P, Abcouwer S, Garcia Garrido M. Dual angiopoietin‐2/VEGF‐A neutralisation prevents vascular leakage, cell death and subretinal macrophage infiltration in mouse models of retinal ischaemia/reperfusion injury and spontaneous CNV. Acta Ophthalmol 2022. [DOI: 10.1111/j.1755-3768.2022.199] [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: 11/27/2022]
Affiliation(s)
- Jérémie Canonica
- Roche Pharma Research and Early Development Roche Innovation Center Basel Switzerland
| | - Sumathi Shanmugam
- Department of Ophthalmology and Visual Sciences Kellogg Eye Center University of Michigan Medical School Ann Arbor MI USA
| | - Cheng‐mao Lin
- Department of Ophthalmology and Visual Sciences Kellogg Eye Center University of Michigan Medical School Ann Arbor MI USA
| | - David Antonetti
- Department of Ophthalmology and Visual Sciences Kellogg Eye Center University of Michigan Medical School Ann Arbor MI USA
| | - Richard Foxton
- Roche Pharma Research and Early Development Roche Innovation Center Basel Switzerland
| | - Sabine Uhles
- Roche Pharma Research and Early Development Roche Innovation Center Basel Switzerland
| | - Peter Westenkow
- Roche Pharma Research and Early Development Roche Innovation Center Basel Switzerland
| | - Steve Abcouwer
- Department of Ophthalmology and Visual Sciences Kellogg Eye Center University of Michigan Medical School Ann Arbor MI USA
| | - Marina Garcia Garrido
- Roche Pharma Research and Early Development Roche Innovation Center Basel Switzerland
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Canonica J, Uhles S, Foxton R, Revelant F, Cole N, Westenkow P, Scheidl S, Ullmer C. New data in a mouse model of spontaneous choroidal neovascularisation support the role of angiopoietin‐2 inhibition in driving sustained vascular stabilisation and reduced fibrosis progression. Acta Ophthalmol 2021. [DOI: 10.1111/aos.0082] [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: 10/22/2022]
Affiliation(s)
- Jérémie Canonica
- Roche Pharma Research and Early Development Roche Innovation Center Basel Switzerland
| | - Sabine Uhles
- Roche Pharma Research and Early Development Roche Innovation Center Basel Switzerland
| | - Richard Foxton
- Roche Pharma Research and Early Development Roche Innovation Center Basel Switzerland
| | - Franco Revelant
- Roche Pharma Research and Early Development Roche Innovation Center Basel Switzerland
| | - Nadine Cole
- Roche Pharma Research and Early Development Roche Innovation Center Basel Switzerland
| | - Peter Westenkow
- Roche Pharma Research and Early Development Roche Innovation Center Basel Switzerland
| | | | - Christoph Ullmer
- Roche Pharma Research and Early Development Roche Innovation Center Basel Switzerland
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Noda M, Omori S, Nemoto R, Sukumoda E, Takita M, Foxton R, Nozaki K, Miura H. Strain analysis of anterior resin-bonded fixed dental prostheses with different thicknesses of high translucent zirconia. J Dent Sci 2020; 16:628-635. [PMID: 33854712 PMCID: PMC8025231 DOI: 10.1016/j.jds.2020.10.002] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/07/2020] [Indexed: 12/05/2022] Open
Abstract
Background/purpose High translucent zirconia has been used as a new monolithic zirconia prosthesis, which has the potential to make anterior resin-bonded fixed dental prostheses (RBFDPs) without veneering porcelain. However, it is unclear whether the RBFDPs retainer can be thinned as much as conventional zirconia RBFDPs. The aim of this study was to assess the usability of high translucent zirconia RBFDPs with a thin retainer thickness by evaluating differences in retainer thickness on the surface strain. Materials and methods A model with a missing upper lateral incisor was used. The abutment teeth were upper central incisor and canine. Three types of RBFDPs were fabricated as follows: metal RBFDPs with a retainer thickness of 0.8 mm (0.8M), and high translucent zirconia RBFDPs with a retainer thicknesses of 0.8 and 0.5 mm (0.8Z, 0.5Z) (n = 10). The fitness of the margins was evaluated by the silicone replica technique. The surface strain of each retainer under static loading was measured and statistically analyzed using a t-test with Bonferroni correction. Results The marginal fitness of all RBFDPs was under 76.1 μm, which was clinically acceptable. Each strain of the 0.8Z and 0.5Z groups was significantly lower than that of the 0.8M (p < 0.05). There was no difference in strain of the zirconia RBFDPs even if the retainer thickness was changed. Conclusion Our results suggest that the high translucent zirconia RBFDPs can be manufactured with a retainer thickness of 0.5 mm, which reduces the amount of tooth preparation compared to the metal RBFDPs.
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Affiliation(s)
- Michiko Noda
- Department of Fixed Prosthodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Satoshi Omori
- Department of Fixed Prosthodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Reina Nemoto
- Department of Fixed Prosthodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Erika Sukumoda
- Department of Fixed Prosthodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Mina Takita
- Department of Fixed Prosthodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Richard Foxton
- Restorative Dentistry, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, London, UK
| | - Kosuke Nozaki
- Department of Fixed Prosthodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Hiroyuki Miura
- Department of Fixed Prosthodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
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Regula JT, Lundh von Leithner P, Foxton R, Barathi VA, Chui Ming GC, Tun SBB, Wey YS, Iwata D, Dostalek M, Moelleken J, Stubenrauch KG, Nogoceke E, Widmer G, Strassburger P, Koss MJ, Klein C, Shima DT, Hartmann G. Targeting key angiogenic pathways with a bispecific CrossMAb optimized for neovascular eye diseases. EMBO Mol Med 2019; 11:emmm.201910666. [PMID: 31040127 DOI: 10.15252/emmm.201910666] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Ben Gassem A, Foxton R, Bister D, Newton JT. Patients' Acceptability of Computer-Based Information on Hypodontia: A Randomized Controlled Trial. JDR Clin Trans Res 2019; 3:246-255. [PMID: 30938602 DOI: 10.1177/2380084418773992] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [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: 11/16/2022] Open
Abstract
OBJECTIVES To compare patients' acceptability of a hypodontia-specific interactive computer-based education material (ICB-EM) versus a British Orthodontic Society (BOS) hypodontia leaflet. TRIAL DESIGN Two-arm parallel randomized controlled trial, 1:1 allocation ratio. METHODS The study was conducted at a specialized secondary care facility in the Greater London area. Ninety-six new hypodontia patients aged 14 y and older were randomly assigned to the control group ( n = 49) receiving the BOS leaflet or the intervention group ( n = 47) receiving the ICB-EM. The main outcome measure was patients' evaluation of the intervention measured by the treatment evaluation inventory. RESULTS The analyzed sample comprised 76 participants: control group ( n = 38) and intervention group ( n = 38). The mean age of the sample was 19 y (SD = 7.24) and 20.3 y (SD = 6.9) for the control and intervention group, respectively. The intervention group was significantly more satisfied with the ICB-EM than individuals who received the BOS leaflet ( t = -3.53, P = 0.001). CONCLUSION Patients preferred the computer-based information. KNOWLEDGE TRANSFER STATEMENT Patients attending dental care in the 21st century are adept in the use of computerised facilities for obtaining information. The results of the study will provide valuable evidence for clinicians on the level of acceptability of the patients toward interactive computer based health education as opposed to traditional paper leaflets.
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Affiliation(s)
- A Ben Gassem
- 1 Taibah University, Dental College, Madinah, Saudi Arabia
| | - R Foxton
- 2 Kings College London, Dental Institute, Guys Hospital, London, UK
| | - D Bister
- 2 Kings College London, Dental Institute, Guys Hospital, London, UK
| | - J T Newton
- 3 Kings College London, Dental Institute, Denmark Hill, London, UK
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Alqarni D, Nakajima M, Hosaka K, Ide K, Nagano D, Wada T, Ikeda M, Mamanee T, Thanatvarakorn O, Prasansuttiporn T, Foxton R, Tagami J. The repair bond strength to resin matrix in cured resin composites after water aging. Dent Mater J 2018; 38:233-240. [PMID: 30449829 DOI: 10.4012/dmj.2018-044] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [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: 11/23/2022]
Abstract
The repair microshear bond strengths (µSBSs) to resin matrices in 4 different cured-composites after water storage (0, 60 s, 1 week, 1 month) were evaluated. Three different adhesive application methods to the cured-composites were performed; (1) none, (2) onestep self-etch adhesive application, and (3) one-step self-etch adhesive application with a silane coupling agent. Degree of conversion (DC) of the composite discs was determined using ATR/FT-IR with a time-based spectrum analysis. Initially, the amount of un-reacted resin monomers in the repaired cured-composite contributed to the bonding performance of newly-filled uncured-composite to resin matrix of the cured-composite. Adhesive application could not improve their repair µSBS. After 1-month of water-storage, the repair µSBS was dependent on material, which either reduced or did not and was not influenced by their amount of un-reacted resin monomers. When repairing aged composite resin, the appropriate adhesive application procedures were different among resin composites.
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Affiliation(s)
- Dhaifallah Alqarni
- Department of Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Masatoshi Nakajima
- Department of Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Keiichi Hosaka
- Department of Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Kurumi Ide
- Department of Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Daiki Nagano
- Department of Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Takehiro Wada
- Department of Advanced Biomaterials, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Masaomi Ikeda
- Department of Oral Prosthetic Engineering, Graduate School, Tokyo Medical and Dental University
| | - Teerapong Mamanee
- Department of Restorative Dentistry and Periodontology, Faculty of Dentistry, Chiangmai University
| | | | - Taweesak Prasansuttiporn
- Department of Restorative Dentistry and Periodontology, Faculty of Dentistry, Chiangmai University.,Center of Excellence in Materials Science and Technology, Chiang Mai University
| | - Richard Foxton
- Restorative Dentistry, King's College London Dental Institute, King's College London
| | - Junji Tagami
- Department of Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
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13
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Araoka D, Hosaka K, Nakajima M, Foxton R, Thanatvarakorn O, Prasansuttiporn T, Chiba A, Sato K, Takahashi M, Otsuki M, Tagami J. The strategies used for curing universal adhesives affect the micro-bond strength of resin cement used to lute indirect resin composites to human dentin. Dent Mater J 2018; 37:506-514. [PMID: 29491200 DOI: 10.4012/dmj.2017-240] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We evaluated the effect of different curing strategies for universal adhesives on micro-tensile bond strength (μTBS) between resin cement and dentin and/or between resin cement and indirect resin composite. Flat coronal dentin surfaces and composite resin disks were pretreated with silane-containing universal adhesives, with or without light-curing on the dentin-side and/or composite resin disk-side. Resin disks were luted onto the pretreated dentin surfaces with the corresponding dual-cure adhesive resin cements and light-cured, and cut into beams after 24-h water storage. After 0 or 10,000 thermocycles (5ºC/55ºC) in a water bath, the μTBS of the composite resin disk-dentin beam was tested. The μTBS was highest when universal adhesives were applied to both the dentin- and the indirect composite resin disk-side, followed by light-curing. Thermocycling decreased μTBS in all but the Scotchbond Universaltreated group, with light-curing on both sides. The effect of curing strategies is dependent upon the materials.
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Affiliation(s)
- Daisuke Araoka
- Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Keiichi Hosaka
- Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Masatoshi Nakajima
- Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Richard Foxton
- Restorative Dentistry, King's College London Dental Institute, King's College London
| | | | - Taweesak Prasansuttiporn
- Department of Restorative Dentistry and Periodontology, Faculty of Dentistry, Chiangmai University
| | - Ayaka Chiba
- Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Kento Sato
- Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Masahiro Takahashi
- Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Masayuki Otsuki
- Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Junji Tagami
- Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
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14
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Taguchi K, Hosaka K, Ikeda M, Kishikawa R, Foxton R, Nakajima M, Tagami J. The effect of warm air-blowing on the microtensile bond strength of one-step self-etch adhesives to root canal dentin. J Prosthodont Res 2018; 62:330-336. [PMID: 29397352 DOI: 10.1016/j.jpor.2017.12.006] [Citation(s) in RCA: 4] [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: 04/26/2017] [Revised: 12/19/2017] [Accepted: 12/21/2017] [Indexed: 10/18/2022]
Abstract
PURPOSE The use of warm air-blowing to evaporate solvents of one-step self-etch adhesive systems (1-SEAs) has been reported to be a useful method. The purpose of this study was to evaluate the effect of warm air-blowing on root canal dentin. METHODS Four 1-SEAs (Clearfil Bond SE ONE, Unifil Core EM self-etch bond, Estelink, BeautiDualbond EX) were used. Each 1-SEA was applied to root canal dentin according to the manufacturers' instructions. After the adhesives were applied, solvent was evaporated using either normal air (23±1°C) or warm air (80±1°C) for 20s, and resin composite was placed in the post spaces. The air from the dryer, which could be used in normal- or hot-air-mode, was applied at a distance of 5cm above the root canal cavity in the direction of tooth axis. The temperature of the stream of air from the dryer in the hot-air-mode was 80±1°C, and in the normal mode, 23±1°C. After water storage of the specimens for 24h, the μTBS were evaluated at the coronal and apical regions. The μTBSs were statistically analyzed using three-way ANOVA and Student's t-test with Bonferroni correction (α=0.05). RESULTS The warm air-blowing significantly increased the μTBS of all 1-SEAs at the apical regions, and also significantly increased the μTBS of two adhesives (Estelink and BeautiDualBond EX) at coronal regions. CONCLUSIONS The μTBS of 1-SEAs to root canal dentin was improved by using warm air-blowing.
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Affiliation(s)
- Keita Taguchi
- Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Keiichi Hosaka
- Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
| | - Masaomi Ikeda
- Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Ryuzo Kishikawa
- Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Richard Foxton
- King's College London Dental Institute at Guy's, King's and St Thomas' Hospitals, King's College London, London, UK
| | - Masatoshi Nakajima
- Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Junji Tagami
- Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
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15
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Feng L, Ju M, Lee KYV, Mackey A, Evangelista M, Iwata D, Adamson P, Lashkari K, Foxton R, Shima D, Ng YS. A Proinflammatory Function of Toll-Like Receptor 2 in the Retinal Pigment Epithelium as a Novel Target for Reducing Choroidal Neovascularization in Age-Related Macular Degeneration. Am J Pathol 2017; 187:2208-2221. [PMID: 28739342 DOI: 10.1016/j.ajpath.2017.06.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 05/16/2017] [Accepted: 06/08/2017] [Indexed: 11/28/2022]
Abstract
Current treatments for choroidal neovascularization, a major cause of blindness for patients with age-related macular degeneration, treat symptoms but not the underlying causes of the disease. Inflammation has been strongly implicated in the pathogenesis of choroidal neovascularization. We examined the inflammatory role of Toll-like receptor 2 (TLR2) in age-related macular degeneration. TLR2 was robustly expressed by the retinal pigment epithelium in mouse and human eyes, both normal and with macular degeneration/choroidal neovascularization. Nuclear localization of NF-κB, a major downstream target of TLR2 signaling, was detected in the retinal pigment epithelium of human eyes, particularly in eyes with advanced stages of age-related macular degeneration. TLR2 antagonism effectively suppressed initiation and growth of spontaneous choroidal neovascularization in a mouse model, and the combination of anti-TLR2 and antivascular endothelial growth factor receptor 2 yielded an additive therapeutic effect on both area and number of spontaneous choroidal neovascularization lesions. Finally, in primary human fetal retinal pigment epithelium cells, ligand binding to TLR2 induced robust expression of proinflammatory cytokines, and end products of lipid oxidation had a synergistic effect on TLR2 activation. Our data illustrate a functional role for TLR2 in the pathogenesis of choroidal neovascularization, likely by promoting inflammation of the retinal pigment epithelium, and validate TLR2 as a novel therapeutic target for reducing choroidal neovascularization.
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Affiliation(s)
- Lili Feng
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Meihua Ju
- University College of London Institute of Ophthalmology, London, United Kingdom; Department of Ocular Biology and Therapeutics, University College of London Institute of Ophthalmology, London, United Kingdom
| | - Kei Ying V Lee
- University College of London Institute of Ophthalmology, London, United Kingdom; Department of Ocular Biology and Therapeutics, University College of London Institute of Ophthalmology, London, United Kingdom
| | - Ashley Mackey
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Mariasilvia Evangelista
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Daiju Iwata
- University College of London Institute of Ophthalmology, London, United Kingdom; Department of Ocular Biology and Therapeutics, University College of London Institute of Ophthalmology, London, United Kingdom
| | - Peter Adamson
- University College of London Institute of Ophthalmology, London, United Kingdom
| | - Kameran Lashkari
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Richard Foxton
- University College of London Institute of Ophthalmology, London, United Kingdom; Department of Ocular Biology and Therapeutics, University College of London Institute of Ophthalmology, London, United Kingdom
| | - David Shima
- University College of London Institute of Ophthalmology, London, United Kingdom; Department of Ocular Biology and Therapeutics, University College of London Institute of Ophthalmology, London, United Kingdom
| | - Yin Shan Ng
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts.
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16
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Sato K, Hosaka K, Takahashi M, Ikeda M, Tian F, Komada W, Nakajima M, Foxton R, Nishitani Y, Pashley DH, Tagami J. Dentin Bonding Durability of Two-step Self-etch Adhesives with Improved of Degree of Conversion of Adhesive Resins. J Adhes Dent 2017; 19:31-37. [PMID: 28195277 DOI: 10.3290/j.jad.a37726] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
PURPOSE To evaluate (1) the initial and long-term microtensile bond strengths of two-step self-etch adhesives with different degrees of conversion (DC); (2) the elastic modulus of the respective adhesive resins; (3) the water sorption of the respective adhesive resins. MATERIALS AND METHODS Two two-step self-etch adhesives, Clearfil SE Bond (CSE) and Clearfil SE Bond 2 (CSE2) were used in this study. The DC was determined using ATR/FT-IR with a time-based spectrum analysis. Midcoronal flat dentin surfaces of 24 human molars were prepared with 600-grit SiC paper for microtensile bond strength (µTBS) testing. CSE and CSE2 were applied to the dentin surfaces according to the manufacturer's instructions, followed by composite buildups. The µTBS was measured after water storage for 24 h, 6 months, and 1 year. The elastic modulus (before and after 1 month of water immersion) was determined by the three-point flexural bending test and water sorption values by the water sorption test. RESULTS CSE2 showed significantly higher DC than CSE. The µTBS of CSE2 was significantly higher than that of CSE in all water storage periods. One-year water storage decreased the µTBS of CSE; however, it did not decrease that of CSE2. Regarding the polymerized adhesive resins, the elastic modulus of CSE2 was significantly higher than that of CSE before and after water immersion (p < 0.001), and the water sorption of CSE was higher than that of CSE2. CONCLUSIONS The higher DC of adhesive resins of two-step self-etch adhesives resists water aging and improves the initial bond strengths and durability of the resin-dentin bond.
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17
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Regula JT, Lundh von Leithner P, Foxton R, Barathi VA, Gemmy Cheung CM, Bo Tun SB, Wey YS, Iwata D, Dostalek M, Moelleken J, Stubenrauch KG, Nogoceke E, Widmer G, Strassburger P, Koss MJ, Klein C, Shima DT, Hartmann G. Targeting key angiogenic pathways with a bispecific CrossMAb optimized for neovascular eye diseases. EMBO Mol Med 2017; 9:985. [PMID: 28533211 DOI: 10.15252/emmm.201707895] [Citation(s) in RCA: 4] [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] [Indexed: 11/09/2022] Open
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18
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Gassem AB, Foxton R, Bister D, Newton T. Development of a measure of hypodontia patients’ expectations of the process and outcome of combined orthodontic and restorative treatment. J Dent 2016; 55:114-120. [DOI: 10.1016/j.jdent.2016.10.011] [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: 04/27/2016] [Revised: 10/10/2016] [Accepted: 10/19/2016] [Indexed: 10/20/2022] Open
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19
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Regula JT, Lundh von Leithner P, Foxton R, Barathi VA, Cheung CMG, Bo Tun SB, Wey YS, Iwata D, Dostalek M, Moelleken J, Stubenrauch KG, Nogoceke E, Widmer G, Strassburger P, Koss MJ, Klein C, Shima DT, Hartmann G. Targeting key angiogenic pathways with a bispecific CrossMAb optimized for neovascular eye diseases. EMBO Mol Med 2016; 8:1265-1288. [PMID: 27742718 PMCID: PMC5090659 DOI: 10.15252/emmm.201505889] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Anti‐angiogenic therapies using biological molecules that neutralize vascular endothelial growth factor‐A (VEGF‐A) have revolutionized treatment of retinal vascular diseases including age‐related macular degeneration (AMD). This study reports preclinical assessment of a strategy to enhance anti‐VEGF‐A monotherapy efficacy by targeting both VEGF‐A and angiopoietin‐2 (ANG‐2), a factor strongly upregulated in vitreous fluids of patients with retinal vascular disease and exerting some of its activities in concert with VEGF‐A. Simultaneous VEGF‐A and ANG‐2 inhibition was found to reduce vessel lesion number, permeability, retinal edema, and neuron loss more effectively than either agent alone in a spontaneous choroidal neovascularization (CNV) model. We describe the generation of a bispecific domain‐exchanged (crossed) monoclonal antibody (CrossMAb; RG7716) capable of binding, neutralizing, and depleting VEGF‐A and ANG‐2. RG7716 showed greater efficacy than anti‐VEGF‐A alone in a non‐human primate laser‐induced CNV model after intravitreal delivery. Modification of RG7716's FcRn and FcγR binding sites disabled the antibodies' Fc‐mediated effector functions. This resulted in increased systemic, but not ocular, clearance. These properties make RG7716 a potential next‐generation therapy for neovascular indications of the eye.
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Affiliation(s)
- Jörg T Regula
- Roche Pharma Research and Early Development, Roche Innovation Center München, Penzberg, Germany
| | - Peter Lundh von Leithner
- Department of Ocular Biology and Therapeutics, UCL London Institute of Ophthalmology, London, UK
| | - Richard Foxton
- Department of Ocular Biology and Therapeutics, UCL London Institute of Ophthalmology, London, UK.,Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Veluchamy A Barathi
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute The Academia, Singapore, Singapore.,The Ophthalmology & Visual Sciences Academic Clinical Program, DUKE-NUS Graduate Medical School, Singapore, Singapore
| | - Chui Ming Gemmy Cheung
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute The Academia, Singapore, Singapore
| | - Sai Bo Bo Tun
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute The Academia, Singapore, Singapore
| | - Yeo Sia Wey
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute The Academia, Singapore, Singapore
| | - Daiju Iwata
- Department of Ocular Biology and Therapeutics, UCL London Institute of Ophthalmology, London, UK
| | - Miroslav Dostalek
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Jörg Moelleken
- Roche Pharma Research and Early Development, Roche Innovation Center München, Penzberg, Germany
| | - Kay G Stubenrauch
- Roche Pharma Research and Early Development, Roche Innovation Center München, Penzberg, Germany
| | - Everson Nogoceke
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Gabriella Widmer
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Pamela Strassburger
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Michael J Koss
- Department of Ophthalmology, Goethe University, Frankfurt am Main, Germany.,Department of Ophthalmology, Ruprecht Karls University, Heidelberg, Germany
| | - Christian Klein
- Roche Pharma Research and Early Development, Roche Innovation Center Zürich, F. Hoffmann-La Roche Ltd, Zürich, Switzerland
| | - David T Shima
- Department of Ocular Biology and Therapeutics, UCL London Institute of Ophthalmology, London, UK
| | - Guido Hartmann
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
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20
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Foxton R, Osborne A, Martin KR, Ng YS, Shima DT. Distal retinal ganglion cell axon transport loss and activation of p38 MAPK stress pathway following VEGF-A antagonism. Cell Death Dis 2016; 7:e2212. [PMID: 27148685 PMCID: PMC4917649 DOI: 10.1038/cddis.2016.110] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [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: 11/05/2015] [Revised: 03/04/2016] [Accepted: 03/16/2016] [Indexed: 01/10/2023]
Abstract
There is increasing evidence that VEGF-A antagonists may be detrimental to neuronal health following ocular administration. Here we investigated firstly the effects of VEGF-A neutralization on retinal neuronal survival in the Ins2Akita diabetic and JR5558 spontaneous choroidal neovascularization (CNV) mice, and then looked at potential mechanisms contributing to cell death. We detected elevated apoptosis in the ganglion cell layer in both these models following VEGF-A antagonism, indicating that even when vascular pathologies respond to treatment, neurons are still vulnerable to reduced VEGF-A levels. We observed that retinal ganglion cells (RGCs) seemed to be the cells most susceptible to VEGF-A antagonism, so we looked at anterograde transport in these cells, due to their long axons requiring optimal protein and organelle trafficking. Using cholera toxin B-subunit tracer studies, we found a distal reduction in transport in the superior colliculus following VEGF-A neutralization, which occurred prior to net RGC loss. This phenomenon of distal transport loss has been described as a feature of early pathological changes in glaucoma, Alzheimer's and Parkinson's disease models. Furthermore, we observed increased phosphorylation of p38 MAPK and downstream Hsp27 stress pathway signaling in the retinas from these experiments, potentially providing a mechanistic explanation for our findings. These experiments further highlight the possible risks of using VEGF-A antagonists to treat ocular neovascular disease, and suggest that VEGF-A may contribute to the maintenance and function of axonal transport in neurons of the retina.
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Affiliation(s)
- R Foxton
- Department of Ocular Biology and Therapeutics, University College London, Institute of Ophthalmology, London, UK
| | - A Osborne
- John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, UK
| | - K R Martin
- John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, UK.,Wellcome Trust Medical Research Council Cambridge Stem Cell Institute, Cambridge, UK.,Cambridge NIHR Biomedical Research Centre, Cambridge, UK.,Eye Department, Addenbrooke's Hospital, Cambridge, UK
| | - Y-S Ng
- Department of Ocular Biology and Therapeutics, University College London, Institute of Ophthalmology, London, UK.,The Schepens Eye Research Institute and Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - D T Shima
- Department of Ocular Biology and Therapeutics, University College London, Institute of Ophthalmology, London, UK
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21
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Sukumaran P, Foxton R, Wilson R, Mallet R, Fenlon M. The Effect of Disinfectant Solutions on the Durability of the Bond between Resin Based Cement and Non-Precious Metal Alloy. SAINS MALAYS 2015. [DOI: 10.17576/jsm-2015-4403-13] [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: 11/17/2022]
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22
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Bunker S, Holeniewska J, Vijay S, Dahlmann-Noor A, Khaw P, Ng YS, Shima D, Foxton R. Experimental glaucoma induced by ocular injection of magnetic microspheres. J Vis Exp 2015. [PMID: 25742031 PMCID: PMC4354616 DOI: 10.3791/52400] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [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] [Indexed: 01/13/2023] Open
Abstract
Progress in understanding the pathophysiology, and providing novel treatments for glaucoma is dependent on good animal models of the disease. We present here a protocol for elevating intraocular pressure (IOP) in the rat, by injecting magnetic microspheres into the anterior chamber of the eye. The use of magnetic particles allows the user to manipulate the beads into the iridocorneal angle, thus providing a very effective blockade of fluid outflow from the trabecular meshwork. This leads to long-lasting IOP rises, and eventually neuronal death in the ganglion cell layer (GCL) as well as optic nerve pathology, as seen in patients with the disease. This method is simple to perform, as it does not require machinery, specialist surgical skills, or many hours of practice to perfect. Furthermore, the pressure elevations are very robust, and reinjection of the magnetic microspheres is not usually required unlike in some other models using plastic beads. Additionally, we believe this method is suitable for adaptation for the mouse eye.
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Affiliation(s)
- Shannon Bunker
- Ocular Biology and Therapeutics, University College London Institute of Ophthalmology
| | - Joanna Holeniewska
- Ocular Biology and Therapeutics, University College London Institute of Ophthalmology
| | | | | | - Peng Khaw
- University College London Institue of Ophthalmology; NIHR Biomedical Research Centre, Moorfields Eye Hospital
| | - Yin-Shan Ng
- Schepens Eye Research Institute, Harvard Medical School
| | - David Shima
- Ocular Biology and Therapeutics, University College London Institute of Ophthalmology; Hoffman-La Roche
| | - Richard Foxton
- Ocular Biology and Therapeutics, University College London Institute of Ophthalmology;
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23
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Kainose K, Nakajima M, Foxton R, Wakabayashi N, Tagami J. Stress distribution in root filled teeth restored with various post and core techniques: effect of post length and crown height. Int Endod J 2014; 48:1023-32. [DOI: 10.1111/iej.12397] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 10/10/2014] [Indexed: 11/29/2022]
Affiliation(s)
- K. Kainose
- Cariology and Operative Dentistry; Oral Restitution Department; Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Tokyo Japan
| | - M. Nakajima
- Cariology and Operative Dentistry; Oral Restitution Department; Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Tokyo Japan
| | - R. Foxton
- Division of Conservative Dentistry; King's College London Dental Institute at Guy's; King's and St Thomas' Hospitals; King's College London; London UK
| | - N. Wakabayashi
- Removable Partial Prosthodontics Department; Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Tokyo Japan
| | - J. Tagami
- Cariology and Operative Dentistry; Oral Restitution Department; Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Tokyo Japan
- Global Center of Excellence (GCOE) Program; International Research Center for Molecular Science in Tooth and Bone Diseases; Tokyo Medical and Dental University; Tokyo Japan
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24
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Argolo S, Mathias P, Aguiar T, Lima A, Santos S, Foxton R, Cavalcanti A. Effect of agitation and storage temperature on water sorption and solubility of adhesive systems. Dent Mater J 2014; 34:1-6. [PMID: 24998169 DOI: 10.4012/dmj.2014-033] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The purpose of this study was to evaluate the influence of storage temperature and flask agitation on the water sorption (WS) and solubility (SL) of simplified adhesive systems. Seventy-two disc-shaped specimens were prepared according to the adhesive system (water/ethanol-based: Adper Single Bond 2; and water-based: One Coat Bond SL) and experimental conditions tested (mechanical agitation and storage temperature). Statistical analysis (3-way ANOVA, alpha=5%) found significantly greater WS and SL means for the water/ethanol-based system when compared to the water-based. Irrespective of factors studied, significant differences in WS and SL were noted between cold and room temperatures, with greater values been obtained at 1°C, and lower ones at 20°C. Agitation provided increased WS for both materials at all temperatures, but did not affect their SL. The mechanical agitation of the flask may negatively affect the dynamics of diffusion of simplified adhesive systems, even at extremely cold or warm temperatures.
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Affiliation(s)
- Saryta Argolo
- Dentistry Course, Northeast Independent School (FAINOR)
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25
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Hashem DF, Foxton R, Manoharan A, Watson TF, Banerjee A. The physical characteristics of resin composite-calcium silicate interface as part of a layered/laminate adhesive restoration. Dent Mater 2014; 30:343-9. [PMID: 24418628 DOI: 10.1016/j.dental.2013.12.010] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [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: 09/05/2013] [Accepted: 12/17/2013] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To compare in-vitro micro-shear bond strengths (μSBS) of resin composite to calcium silicate cement (Biodentine™) vs. glass ionomer cement vs. resin modified glass ionomer cement (RM-GIC) using an adhesive in self-etch (SE)/total etch (TE) mode after aging three substrates and bond and characterizing their failure modes. METHODS Resin composite was SE/TE bonded to 920 standardized disks of Biodentine™, GIC & RM-GIC. Dividing samples into two groups, the first underwent early (t=0min, 5min, 20min, 24h) or delayed (t=2wk, 1 month, 3 months, 6 months) substrate aging before bonding and μSBS (t=24h) testing. In the second, adhesive was applied after either early (t=5min) or delayed (t=2wk) substrate aging and then tested after bond aging (t=2wk, 1 month, 3 months, 6 months). The failure modes were identified using stereomicroscope. SEM images of selected samples were analyzed. RESULTS No significant differences were observed between (SE)/(TE) bonding modes (P=0.42). With substrate aging, a significant reduction in μSBS occurred between early and delayed time intervals for Biodentine™ (P=0.001), but none for the GIC/RM-GIC (P=0.465, P=0.512 respectively). With bond aging, there was no significant difference between time intervals for all groups, except at 6 months for the GIC (P<0.05). Modes of failure were primarily cohesive within all the substrates (68.82%) followed by adhesive failure at the resin-substrate interface (21.71%). SIGNIFICANCE Biodentine™ is a weak restorative material in its early setting phase. Placing the overlying resin composite as part of the laminate/layered definitive restoration is best delayed for >2wk to allow sufficient intrinsic maturation to withstand contraction forces from the resin composite. A total-etch or self-etch adhesive may be used.
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Affiliation(s)
- Danya F Hashem
- Unit of Conservative Dentistry, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK; Unit of Biomaterials, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK.
| | - Richard Foxton
- Unit of Conservative Dentistry, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK
| | - Andiappan Manoharan
- Biostatistics & Research Methods Centre, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK
| | - Timothy F Watson
- Unit of Conservative Dentistry, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK; Unit of Biomaterials, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK
| | - Avijit Banerjee
- Unit of Conservative Dentistry, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK; Unit of Biomaterials, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK
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Alhashimi R, Mannocci F, Foxton R, Deb S. Fabrication and characterization of polymer composites for endodontic use. Int Endod J 2013; 47:574-82. [PMID: 24164059 DOI: 10.1111/iej.12192] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [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: 06/11/2013] [Accepted: 08/31/2013] [Indexed: 11/28/2022]
Abstract
AIM To develop a low-density polyethylene-hydroxyapatite (HA-PE) composite with properties tailored to function as a potential root canal filling material. METHODOLOGY Hydroxyapatite and polyethylene mixed with strontium oxide as a radiopacifier were extruded from a single screw extruder fitted with an appropriate die to form fibres. The composition of the composite was optimized with clinical handling and placement in the canal being the prime consideration. The fibres were characterized using infrared spectroscopy (FTIR), and their thermal properties determined using differential scanning calorimetry (DSC). The tensile strength and elastic modulus of the composite fibres and gutta-percha were compared, dry and after 1 month storage in simulated body fluid (SBF), using a universal testing machine. The radiopacity of the fibres was determined using digital radiography. The interaction of the composites with eugenol was evaluated and compared with gutta-percha. Data of the tensile test were submitted to two-way anova and Bonferroni tests (P < 0.05). RESULTS The endothermic peaks obtained from the DSC studies showed that the melting point of the HA/PE composites ranged between 110.5 and 111.2 °C, whereas gutta-percha exhibited a melting point at 52 °C. The tensile strength and elastic modulus of the silanated HA/PE composites were significantly higher than those of gutta-percha (P < 0.0001) under dry conditions and 1 month storage in SBF. The gutta-percha in eugenol showed a significant increase in the polymer molar mass, whereas the silanated HA/PE composites were unchanged. Radiological evaluations demonstrated that silanated HA/PE fibres were sufficiently radiopaque. CONCLUSION Promising materials for endodontic applications have been developed, offering relevant benefits over the traditional materials in terms of mechanical and chemical properties.
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Affiliation(s)
- R Alhashimi
- Department of Biomaterial, King's College London Dental Institute, London, UK; Department of Conservative Dentistry, King's College London Dental Institute, London, UK
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Profeta A, Mannocci F, Foxton R, Watson T, Feitosa V, De Carlo B, Mongiorgi R, Valdré G, Sauro S. Experimental etch-and-rinse adhesives doped with bioactive calcium silicate-based micro-fillers to generate therapeutic resin–dentin interfaces. Dent Mater 2013; 29:729-41. [DOI: 10.1016/j.dental.2013.04.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 03/17/2013] [Accepted: 04/04/2013] [Indexed: 01/31/2023]
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Dawson LA, Cato KJ, Scott C, Watson JM, Wood MD, Foxton R, de la Flor R, Jones GA, Kew JN, Cluderay JE, Southam E, Murkitt GS, Gartlon J, Pemberton DJ, Jones DN, Davies CH, Hagan J. In vitro and in vivo characterization of the non-peptide NK3 receptor antagonist SB-223412 (talnetant): potential therapeutic utility in the treatment of schizophrenia. Neuropsychopharmacology 2008; 33:1642-52. [PMID: 17728699 DOI: 10.1038/sj.npp.1301549] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [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] [Indexed: 11/09/2022]
Abstract
Neurokinin-3 (NK3) receptors are concentrated in forebrain and basal ganglia structures within the mammalian CNS. This distribution, together with the modulatory influence of NK3 receptors on monoaminergic neurotransmission, has led to the hypothesis that NK3 receptor antagonists may have therapeutic efficacy in the treatment of psychiatric disorders. Here we describe the in vitro and in vivo characterization of the highly selective NK3 receptor antagonist talnetant (SB-223412). Talnetant has high affinity for recombinant human NK3 receptors (pKi 8.7) and demonstrates selectivity over other neurokinin receptors (pKi NK2 = 6.6 and NK1<4). In native tissue-binding studies, talnetant displayed high affinity for the guinea pig NK3 receptor (pKi 8.5). Functionally, talnetant competitively antagonized neurokinin B (NKB)-induced responses at the human recombinant receptor in both calcium and phosphoinositol second messenger assay systems (pA2 of 8.1 and 7.7, respectively). In guinea pig brain slices, talnetant antagonized NKB-induced increases in neuronal firing in the medial habenula (pKB = 7.9) and senktide-induced increases in neuronal firing in the substantia nigra pars compacta (pKB = 7.7) with no diminution of maximal agonist efficacy, suggesting competitive antagonism at native NK3 receptors. Talnetant (3-30 mg/kg i.p.) significantly attenuated senktide-induced 'wet dog shake' behaviors in the guinea pig in a dose-dependent manner. Microdialysis studies demonstrated that acute administration of talnetant (30 mg/kg i.p.) produced significant increases in extracellular dopamine and norepinephrine in the medial prefrontal cortex and attenuated haloperidol-induced increases in nucleus accumbens dopamine levels in the freely moving guinea pigs. Taken together, these data demonstrate that talnetant is a selective, competitive, brain-penetrant NK3 receptor antagonist with the ability to modulate mesolimbic and mesocortical dopaminergic neurotransmission and hence support its potential therapeutic utility in the treatment of schizophrenia.
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Affiliation(s)
- Lee A Dawson
- Psychiatry Centre of Excellence for Drug Discovery, GlaxoSmithKline, Essex, UK.
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Abstract
OBJECTIVE Lost dentures can be a frustrating scenario for both patients and clinicians. This study aimed to find out where dentures were being lost and the level of assistance patients received with denture care. RESULTS The results showed most dentures were lost in the hospital environment, and in many cases patients were not provided with pots in which to store their dentures or offered help or advice on denture care. The provision of new dentures to this patient group is complicated by the fact that in many cases the dentures were over ten years old and many of the patients were over eighty five years old. This makes adaptation to new dentures difficult. CONCLUSIONS It is imperative that protocols are developed and staff trained to minimise the risk of lost dentures and improve the standard of denture care.
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Affiliation(s)
- Leila Michaeli
- Department of Restorative Dentistry, Kings College London Dental Institute at Guy's, King's and St Thomas' Hospitals, London, UK.
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Nikaido T, Nakaoki Y, Ogata M, Foxton R, Tagami J. The resin-coating technique. Effect of a single-step bonding system on dentin bond strengths. J Adhes Dent 2003; 5:293-300. [PMID: 15008336] [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] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
PURPOSE An experimental single-step bonding system, RZ-II, has been developed as a resin coating material for crown preparation. The purpose of this study was to compare the dentin microtensile bond strengths (MTBSs) of RZ-II in direct and indirect use. MATERIALS AND METHODS Human molar dentin was used. The specimens were divided into three groups of n = 20 each. Group 1: RZ-II was applied to the dentin surface once or twice, and built up with a direct composite. Group 2: The dentin surface was provisionally covered and stored in water for 1 day. The provisional material was removed and an indirect composite was then bonded to the dentin surface. Group 3: RZ-II was applied to the dentin surface once or twice for "resin coating" before the placement and removal of provisional material. An indirect composite was then bonded to the coated dentin. After 1 day, MTBSs were measured at a crosshead speed of 1 mm/min. The data were analyzed using one-way ANOVA and Fisher's PLSD test (p < 0.05). The interface between the indirect composite and resin-coated dentin was also observed using a SEM. RESULTS The MTBSs of RZ-II in Groups 1 and 3 were significantly higher than those of Group 2 (p < 0.05). The thickness of the resin-coating layer and the hybrid layer were 5 to 6 microm and less than 1 microm, respectively. CONCLUSION The single-step bonding system, RZ-II, could be useful as a resin coating material for crown preparation.
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Affiliation(s)
- Toru Nikaido
- Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
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Hows MEP, Organ AJ, Murray S, Dawson LA, Foxton R, Heidbreder C, Hughes ZA, Lacroix L, Shah AJ. High-performance liquid chromatography/tandem mass spectrometry assay for the rapid high sensitivity measurement of basal acetylcholine from microdialysates. J Neurosci Methods 2002; 121:33-9. [PMID: 12393159 DOI: 10.1016/s0165-0270(02)00228-5] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [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: 10/27/2022]
Abstract
A high-throughput liquid chromatography tandem mass spectrometry (LC/MS/MS) method has been developed for the analysis of acetylcholine (ACh) in brain dialysates. This separation of ACh is based on cation exchange chromatography with elution buffer consisting of a mixture of ammonium acetate, ammonium formate and acetonitrile. Using isocratic separation conditions, ACh was resolved within a minute and detected using tandem mass spectrometry in the positive ion electrospray mode. The limit of detection for ACh was found to be 1 fmol on column with a S/N ratio of 3:1. The assay has been used routinely for the measurement of ACh in brain dialysates from awake freely moving rats. Furthermore, separation conditions were modified to allow simultaneous measurement of ACh and the acetylcholine esterase inhibitor, neostigmine.
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Affiliation(s)
- Mark E P Hows
- Computational Analytical and Structural Sciences, GlaxoSmithKline, New Frontiers Science Park, Third Avenue, Harlow, CM19 5AW, Essex, UK.
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Heidbreder CA, Foxton R, Cilia J, Hughes ZA, Shah AJ, Atkins A, Hunter AJ, Hagan JJ, Jones DN. Increased responsiveness of dopamine to atypical, but not typical antipsychotics in the medial prefrontal cortex of rats reared in isolation. Psychopharmacology (Berl) 2001; 156:338-51. [PMID: 11549234 DOI: 10.1007/s002130100760] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [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] [Indexed: 10/27/2022]
Abstract
Dopaminergic hypofunction in the medial prefrontal cortex (mPFC) has been associated with the aetiology of negative symptoms and cognitive dysfunction of schizophrenia, which are both alleviated by clozapine and other atypical antipsychotics such as olanzapine. In rodents, early life exposure to stressful experiences such as social isolation produces a spectrum of symptoms emerging in adult life, which can be restored by antipsychotic drugs. The present series of experiments sought to investigate the effect of clozapine (5-10 mg/kg s.c.), olanzapine (5 mg/kg s.c.), and haloperidol (0.5 mg/kg s.c.) on dopamine (DA) and amino acids in the prelimbic/infralimbic subregion of the mPFC in group- and isolation-reared rats. Rats reared in isolation showed significant and robust deficits in prepulse inhibition of the acoustic startle. In group-reared animals, both clozapine and olanzapine produced a significant increase in DA outflow in the mPFC. Isolation-reared rats showed a significant increase in responsiveness to both atypical antipsychotics compared with group-reared animals. In contrast, the administration of haloperidol failed to modify dialysate DA levels in mPFC in either group- or isolation-reared animals. The results also show a positive relationship between the potency of the tested antipsychotics to increase the release of DA in the mPFC and their respective affinities for 5-HT1A relative to DA D2 or D3 receptors. Finally, isolation-reared rats showed enhanced neurochemical responses to the highest dose of clozapine as indexed by alanine, aspartate, GABA, glutamine, glutamate, histidine, and tyrosine. The increased DA responsiveness to the atypical antipsychotic drugs clozapine and olanzapine may explain, at least in part, clozapine- and olanzapine-induced reversal of some of the major behavioral components of the social isolation syndrome, namely hyperactivity and attention deficit.
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Affiliation(s)
- C A Heidbreder
- Centre of Excellence for Drug Discovery in Psychiatry, GlaxoSmithKline Pharmaceuticals, Harlow, Essex, UK.
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