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Chen CH, Pei X, Tulu U, Aghvami M, Chen CT, Gaudillière D, Arioka M, Maghazeh Moghim M, Bahat O, Kolinski M, Crosby T, Felderhoff A, Brunski J, Helms J. A Comparative Assessment of Implant Site Viability in Humans and Rats. J Dent Res 2018; 97:451-459. [PMID: 29202640 PMCID: PMC5863872 DOI: 10.1177/0022034517742631] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Our long-term objective is to devise methods to improve osteotomy site preparation and, in doing so, facilitate implant osseointegration. As a first step in this process, we developed a standardized oral osteotomy model in ovariectomized rats. There were 2 unique features to this model: first, the rats exhibited an osteopenic phenotype, reminiscent of the bone health that has been reported for the average dental implant patient population. Second, osteotomies were produced in healed tooth extraction sites and therefore represented the placement of most implants in patients. Commercially available drills were then used to produce osteotomies in a patient cohort and in the rat model. Molecular, cellular, and histologic analyses demonstrated a close alignment between the responses of human and rodent alveolar bone to osteotomy site preparation. Most notably in both patients and rats, all drilling tools created a zone of dead and dying osteocytes around the osteotomy. In rat tissues, which could be collected at multiple time points after osteotomy, the fate of the dead alveolar bone was followed. Over the course of a week, osteoclast activity was responsible for resorbing the necrotic bone, which in turn stimulated the deposition of a new bone matrix by osteoblasts. Collectively, these analyses support the use of an ovariectomy surgery rat model to gain insights into the response of human bone to osteotomy site preparation. The data also suggest that reducing the zone of osteocyte death will improve osteotomy site viability, leading to faster new bone formation around implants.
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Affiliation(s)
- C.-H. Chen
- Craniofacial Research Center, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Chang Gung University School of Medicine, Taoyuan, Taiwan
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - X. Pei
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - U.S. Tulu
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - M. Aghvami
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - C.-T. Chen
- Craniofacial Research Center, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Chang Gung University School of Medicine, Taoyuan, Taiwan
- Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital at Keelung, Keelung, Taiwan
| | - D. Gaudillière
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - M. Arioka
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
- Department of Clinical Pharmacology, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - M. Maghazeh Moghim
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
- University College London Medical School, University College London, London, UK
| | - O. Bahat
- Private practice, Beverly Hills, CA, USA
| | | | | | | | - J.B. Brunski
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - J.A. Helms
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
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Kolinski M, Plazinska A, Jozwiak K. Recent progress in understanding of structure, ligand interactions and the mechanism of activation of the β₂-adrenergic receptor. Curr Med Chem 2012; 19:1155-63. [PMID: 22300047 DOI: 10.2174/092986712799320547] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 01/16/2012] [Accepted: 01/17/2012] [Indexed: 11/22/2022]
Abstract
The understanding of β₂-adrenergic receptor (β₂AR) interactions with ligands as well as the mechanism of receptor activation changed radically from 2007, when the first crystallographic structure of the receptor was reported. Since then numerous crystallographic studies described interactions with all main classes of β₂AR ligands and with G proteins, which provided a great insight into the molecular structure of the receptor. However, molecular mechanisms of receptor activations remain to be determined. Functional research supported the concept of ligand-directed signaling at β-adrenoceptors. Agonist can activate alternative signaling pathways with different capacities and trigger cellular effects. It indicates that agonists nominally belonging to the same class may bind to and/or stabilize different active conformations of the receptor which are selectively recognized by signaling proteins in the allosteric manner.
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Affiliation(s)
- M Kolinski
- Laboratory of Medicinal Chemistry and Neuroengineering, Medical University of Lublin, ul. W. Chodzki 4a, 20-093 Lublin, Poland
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Bhatia P, Kolinski M, Moaddel R, Jozwiak K, Wainer IW. Determination and modelling of stereoselective interactions of ligands with drug transporters: a key dimension in the understanding of drug disposition. Xenobiotica 2008; 38:656-75. [PMID: 18668426 DOI: 10.1080/00498250802109207] [Citation(s) in RCA: 11] [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: 10/21/2022]
Abstract
1. Stereochemistry is an important dimension in pharmacology and plays a role in every aspect of the pharmacological fate of chiral xenobiotics. This includes small molecule-drug transporter binding. 2. This paper reviews the reported stereoselectivities of substrate and inhibitor interactions with P-glycoprotein and the organic cation transporter obtained using standard functional and binding studies, as well as data obtained from online cellular membrane affinity chromatography studies. 3. The use of stereochemical data in quantitative structure-activity relationship (QSAR) and pharmacophore modelling is also addressed as is the effect of ignoring the fact that small molecule-drug transporter interactions take place in three-dimensional and asymmetric space.
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Affiliation(s)
- P Bhatia
- Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224-6825, USA
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