513 research outputs found

    Comparison of implant stability after different implant surface treatments in dog bone

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    OBJECTIVES: The purpose of this investigation was to evaluate the effects of different implant surface treatments on implant stability in dog mandibles. MATERIAL AND METHODS: A total of 30 implants (Dentium Co, Seoul, Korea) were placed in 5 dog mandibles. Bone quality was assessed at each site. Implant stability was evaluated using 2 different methods. An OsstellTM resonance frequency analyzer (RFA) was used to determine the stability at baseline (day 1), and 3, 6 and 10 weeks after surgery. Animals were euthanized 10 weeks after implant installation. Specimens were obtained and submitted to the laboratory processing. Sections were stained with hematoxylin and eosin for histologic and histomorphometric analyses. All implantation sites in dog mandibles demonstrated bone types II and III. RESULTS AND CONCLUSIONS: All implants showed good primary stability at baseline in terms of insertion torque. The results of this study suggest that surface treatment may have significant effects on biological stability 3 weeks after implant placement. Further studies are needed to confirm these initial observations in poor quality bone

    Controlled manipulation of oxygen vacancies using nanoscale flexoelectricity

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    Oxygen vacancies, especially their distribution, are directly coupled to the electromagnetic properties of oxides and related emergent functionalities that have implication in device applications. Here using a homoepitaxial strontium titanate thin film, we demonstrate a controlled manipulation of the oxygen vacancy distribution using the mechanical force from a scanning probe microscope tip. By combining Kelvin probe force microscopy imaging and phase-field simulations, we show that oxygen vacancies can move under a stress-gradient-induced depolarisation field. When tailored, this nanoscale flexoelectric effect enables a controlled spatial modulation. In motion, the scanning probe tip thereby deterministically reconfigures the spatial distribution of vacancies. The ability to locally manipulate oxygen vacancies on-demand provides a tool for the exploration of mesoscale quantum phenomena, and engineering multifunctional oxide devices.Comment: 35 pages, Main text and the supplementary information combine

    Grape seed proanthocyanidin extract inhibits glutamate-induced cell death through inhibition of calcium signals and nitric oxide formation in cultured rat hippocampal neurons

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    <p>Abstract</p> <p>Background</p> <p>Proanthocyanidin is a polyphenolic bioflavonoid with known antioxidant activity. Some flavonoids have a modulatory effect on [Ca<sup>2+</sup>]<sub>i</sub>. Although proanthocyanidin extract from blueberries reportedly affects Ca<sup>2+ </sup>buffering capacity, there are no reports on the effects of proanthocyanidin on glutamate-induced [Ca<sup>2+</sup>]<sub>i </sub>or cell death. In the present study, the effects of grape seed proanthocyanidin extract (GSPE) on glutamate-induced excitotoxicity was investigated through calcium signals and nitric oxide (NO) in cultured rat hippocampal neurons.</p> <p>Results</p> <p>Pretreatment with GSPE (0.3-10 μg/ml) for 5 min inhibited the [Ca<sup>2+</sup>]<sub>i </sub>increase normally induced by treatment with glutamate (100 μM) for 1 min, in a concentration-dependent manner. Pretreatment with GSPE (6 μg/ml) for 5 min significantly decreased the [Ca<sup>2+</sup>]<sub>i </sub>increase normally induced by two ionotropic glutamate receptor agonists, N-methyl-D-aspartate and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA). GSPE further decreased AMPA-induced response in the presence of 1 μM nimodipine. However, GSPE did not affect the 50 mM K<sup>+</sup>-induced increase in [Ca<sup>2+</sup>]<sub>i</sub>. GSPE significantly decreased the metabotropic glutamate receptor agonist (<it>RS</it>)-3,5-Dihydroxyphenylglycine-induced increase in [Ca<sup>2+</sup>]<sub>i</sub>, but it did not affect caffeine-induced response. GSPE (0.3-6 μg/ml) significantly inhibited synaptically induced [Ca<sup>2+</sup>]<sub>i </sub>spikes by 0.1 mM [Mg<sup>2+</sup>]<sub>o</sub>. In addition, pretreatment with GSPE (6 μg/ml) for 5 min inhibited 0.1 mM [Mg<sup>2+</sup>]<sub>o</sub>- and glutamate-induced formation of NO. Treatment with GSPE (6 μg/ml) significantly inhibited 0.1 mM [Mg<sup>2+</sup>]<sub>o</sub>- and oxygen glucose deprivation-induced neuronal cell death.</p> <p>Conclusions</p> <p>All these data suggest that GSPE inhibits 0.1 mM [Mg<sup>2+</sup>]<sub>o</sub>- and oxygen glucose deprivation-induced neurotoxicity through inhibition of calcium signals and NO formation in cultured rat hippocampal neurons.</p

    Epidemiology and Assessment of Traumatic Spinal Cord Injury With Concomitant Brain Injury: An Observational Study in a Regional Trauma Center

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    Objective To analyze the epidemiological information of patients with traumatic spinal cord injury (SCI) and concomitant traumatic brain injury (TBI) and to suggest points to be aware of during the initial physical examination of patients with SCI. Methods This study was a retrospective, observational study conducted in a regional trauma center. All the records of patients diagnosed with traumatic SCI between 2016 and 2020 were reviewed. A total of 627 patients with confirmed traumatic SCI were hospitalized. A retrospective study was conducted on 363 individuals. Results The epidemiological data of 363 individuals were investigated. Changes in American Spinal Injury Association Impairment Scale (AIS) scores in patients with SCI were evaluated. The initial evaluation was performed on average 11 days after the injury, and a follow-up examination was performed 43 days after. Fourteen of the 24 patients identified as having AIS A and SCI with concomitant TBI in the initial evaluation showed neurologic level of injury (NLI) recovery with AIS B or more. The conversion rate in patients with SCI and concomitant TBI exceeded that reported in previous studies in individuals with SCI. Conclusions Physical, cognitive, and emotional impairments caused by TBI present significant challenges in rehabilitating patients with SCI. In this study, the influence of concomitant TBI lesions could have caused the initial AIS assessment to be incorrect

    Tolerability and Outcomes of First-Line Pemetrexed-Cisplatin Followed by Gefitinib Maintenance Therapy Versus Gefitinib Monotherapy in Korean Patients with Advanced Nonsquamous Non-small Cell Lung Cancer: A Post Hoc Descriptive Subgroup Analysis of a Randomized, Phase 3 Trial

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    Purpose We recently reported on a randomized, open-label, phase 3 trial comparing pemetrexedcisplatin chemotherapy followed by gefitinib maintenance therapy (PC/G) with gefitinib monotherapy in patients with non-small cell lung cancer (NSCLC). Here, we report on a post hoc subgroup analysis of that study assessing the demographics and disposition of the Korean patient subgroup, and comparing the tolerability of PC/G and gefitinib monotherapy and the tumor response with respect to epidermal growth factor receptor (EGFR) status. Materials and Methods Patients, who were 18 years, chemonalve, Korean, light ex-smokers/never-smokers with advanced NSCLC, were randomly assigned (1:1) to PC/G or gefitinib monotherapy. Treatment-emergent adverse events (TEAEs) were graded, and tumor response was measured as change in lesion sum from baseline at best response. The study was registered with ClinicalTrials.gov, NCT01017874. Results Overall, 111 Korean patients were treated (PC/G, 51; gefitinib, 60). Between-arm characteristics were balanced and similar to those of the overall population. Treatment discontinuations due to adverse events were low (PC/G: 1, 2.0%; gefitinib: 7, 11.7%). Overall, 92 patients (82.9%) reported >= 1 TEAE (PC/G, 44; gefitinib, 48); few patients (PC/G, 16; gefitinib, 7) reported severe TEAEs; the most frequent was neutropenia (PC/G arm) and elevated alanine aminotransferase (gefitinib arm). The lesion sum was decreased by PC/G treatment in most patients, regardless of EGFR mutation status, while gefitinib monotherapy reduced the lesion sum in EGFR-positive patients but had no effect in EGFR-negative patients. Conclusion Our results confirm that both PC/G and gefitinib were well tolerated in Korean patients, regardless of EGFR status; however, patients with EGFR wild-type NSCLC may not benefit from gefitinib monotherapy.
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