PURPOSE: In this study, we investigated the effect of silk scaffolds on one-wall periodontal intrabony defects. We conjugated nano-hydroxyapatite (nHA) onto a silk scaffold and then seeded periodontal ligament cells (PDLCs) or dental pulp cells (DPCs) onto the scaffold. METHODS: Five dogs were used in this study. Bilateral 4 mmx2 mm (depthxmesiodistal width), one-wall intrabony periodontal defects were surgically created on the distal side of the mandibular second premolar and the mesial side of the mandibular fourth premolar. In each dog, four of the defects were separately and randomly assigned to the following groups: the PDLC-cultured scaffold transplantation group (PDLC group), the DPC-cultured scaffold transplantation group (DPC group), the normal saline-soaked scaffold transplantation group, and the control group. The animals were euthanized following an 8-week healing interval for clinical, scanning electron microscopy (SEM), and histologic evaluations. RESULTS: There was no sign of inflammation or other clinical signs of postoperative complications. The examination of cell-seeded constructs by SEM provided visual confirmation of the favorable characteristics of nHA-coated silk scaffolds for tissue engineering. The scaffolds exhibited a firm connective porous structure in cross section, and after PDLCs and DPCs were seeded onto the scaffolds and cultured for 3 weeks, the attachment of well-spread cells and the formation of extracellular matrix (ECM) were observed. The histologic analysis revealed that a well-maintained grafted volume was present at all experimental sites for 8 weeks. Small amounts of inflammatory cells were seen within the scaffolds. The PDLC and DPC groups did not have remarkably different histologic appearances. CONCLUSIONS: These observations indicate that nHA-coated silk scaffolds can be considered to be potentially useful biomaterials for periodontal regeneration.
Animals ; Bicuspid ; Biocompatible Materials ; Dental Pulp ; Dogs* ; Extracellular Matrix ; Inflammation ; Microscopy, Electron, Scanning ; Periodontal Ligament ; Postoperative Complications ; Regeneration* ; Silk* ; Tissue Engineering ; Tissue Scaffolds ; Transplants

PURPOSE: Recent interest has focused on intentional replantation to restore an original tooth. Some studies have shown successful results with intentional replantation for periodontally involved teeth. For long-term success of replantation, a healthy periodontal status of the recipient site is required so that delayed replantation is more suitable for periodontally involved teeth. To reveal the ideal timing for delayed replantation of periodontally involved teeth, the healing process of extraction sockets after extraction of periodontitis-induced teeth in rats was evaluated. METHODS: Twenty-eight rats were randomly divided into two groups: a control group (n=8) and test group (n=20). In the test group, periodontitis was induced by a ligature around the cervix of the mandibular first molar of all of the rats. Two weeks later, the mandibular first molars were extracted in all of the animals. The animals were sacrificed on days 0, 3, 7, and 10 after extraction and histological and immunohistochemical analysis was performed. RESULTS: In histological analysis of the test group, inflammatory cell infiltrate was found abundantly in the remaining periodontium 3 days after tooth extraction and decreased gradually at later time points. In immunohistochemical analysis of the test group, both interleukin-6 (IL-6) and, tumor necrosis factor-alpha (TNF-alpha) were numerous in the furcation area at each postextraction day. IL-6 was stained more heavily between 3 and 7 days after extraction; at day 10 after extraction, little staining was observed. TNF-alpha staining was more intense at 3 days after extraction and gradually weakened at later points in time. CONCLUSIONS: Within the limits of this study, it takes at least 10 days to resolve periodontal inflammation in rat extraction sockets.
Animals ; Cervix Uteri ; Female ; Immunohistochemistry ; Inflammation ; Interleukin-6 ; Ligation ; Molar ; Periodontitis ; Periodontium ; Rats ; Replantation ; Tooth ; Tooth Extraction ; Tooth Socket ; Tumor Necrosis Factor-alpha

BACKGROUND AND PURPOSE: To compare the efficacy and safety of antiplatelet agents for the secondary prevention of ischemic stroke based on cytochrome P450 2C19 (CYP2C19) polymorphisms. METHODS: This study was a prospective, multicenter, randomized, parallel-group, open-label, blind genotype trial. First time non-cardiogenic ischemic stroke patients were enrolled and screened within 30 days. Participants were randomized to receive either triflusal or clopidogrel for secondary stroke prevention. The primary outcome was the time from randomization to first recurrent ischemic stroke or hemorrhagic stroke. RESULTS: The required sample size was 1,080 but only 784 (73%) participants were recruited. In patients with a poor CYP2C19 genotype for clopidogrel metabolism (n=484), the risk of recurrent stroke among those who received triflusal treatment was 2.9% per year, which was not significantly different from those who received clopidogrel treatment (2.2% per year; hazard ratio [HR], 1.23; 95% confidence interval [CI], 0.60–2.53). In the clopidogrel treatment group (n=393), 38% had good genotypes and 62% poor genotypes for clopidogrel metabolism. The risk of recurrent stroke in patients with a good CYP2C19 genotype was 1.6% per year, which was not significantly different from those with a poor genotype (2.2% per year; HR, 0.69; 95% CI, 0.26–1.79). CONCLUSIONS: Whilst there were no significant differences between the treatment groups in the rates of stroke recurrence, major vascular events, or coronary revascularization, the efficacy of antiplatelet agents for the secondary prevention of stroke according to CYP2C19 genotype status remains unclear.
Cytochrome P-450 CYP2C19 ; Cytochrome P-450 Enzyme System* ; Cytochromes* ; Genotype ; Humans ; Metabolism ; Platelet Aggregation Inhibitors ; Prospective Studies ; Random Allocation ; Recurrence ; Sample Size ; Secondary Prevention* ; Stroke*

Animals ; Antineoplastic Agents, Alkylating/pharmacology* ; Breast Neoplasms/drug therapy* ; Cell Line ; Cell Line, Tumor ; Cyclophosphamide/pharmacology* ; Ginkgo biloba/chemistry* ; Mammary Neoplasms, Animal/drug therapy* ; Mice ; Plant Extracts/administration & dosage*