Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 49
Filtrar
Más filtros

Bases de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Anal Bioanal Chem ; 414(18): 5217-5237, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35469098

RESUMEN

Triplex DNA nanostructures are one of the most emerging and fascinating self-assembled nanostructures due to their unique nanoparticle-like organization and inherit characteristics. They have attracted numerous interests recently because of their versatile and powerful utility in diverse areas of science and technology, such as clinical or disease diagnosis and stimuli-based drug delivery. This review addresses particularly the utilization of DNA triplexes in the development of biosensors for detecting nucleic acid; strategies in sensing pH, protein activity, ions, or molecules. Finally, an outlook for potential applications of triplex DNA nanoswitches is provided.


Asunto(s)
Técnicas Biosensibles , Nanoestructuras , ADN/química , Nanoestructuras/química , Conformación de Ácido Nucleico
2.
Biochem Biophys Res Commun ; 557: 69-76, 2021 06 11.
Artículo en Inglés | MEDLINE | ID: mdl-33862462

RESUMEN

Remifentanil is a potent, short-acting opioid analgesic drug that can protect tissues from ischemia and reperfusion injury though anti-inflammatory effects. However, the utility of remifentanil in liver regeneration after hepatectomy is not known. Using a 70% hepatectomy mouse model (PHx), we found that preconditioning animals with 4 µg/kg remifentanil enhanced liver regeneration through supporting hepatocyte proliferation but not through anti-inflammatory effects. These effects were also phenocopied in vitro where 40 mM remifentanil promoted the proliferation of primary mouse hepatocyte cultures. We further identified that remifentanil treatment increased the expression of ß-arrestin 2 in vivo and in vitro. Demonstrating specificity, remifentanil preconditioning failed to promote liver regeneration in liver-specific ß-arrestin 2 knockout (CKO) mice subjected to PHx. While remifentanil increased the expression of activated (phosphorylated)-ERK and cyclin D1 in PHx livers, their levels were not significantly changed in remifentanil-treated CKO mice nor in WT mice pretreated with the ERK inhibitor U0126. Our findings suggest that remifentanil promotes liver regeneration via upregulation of a ß-arrestin 2/ERK/cyclin D1 axis, with implications for improving regeneration process after hepatectomy.


Asunto(s)
Ciclina D1/metabolismo , Regeneración Hepática , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Remifentanilo/farmacología , Daño por Reperfusión/terapia , Arrestina beta 2/metabolismo , Analgésicos Opioides/farmacología , Animales , Proliferación Celular/fisiología , Células Cultivadas , Modelos Animales de Enfermedad , Hepatectomía , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Daño por Reperfusión/metabolismo , Daño por Reperfusión/patología , Regulación hacia Arriba
3.
Cancer Sci ; 108(5): 897-909, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28208216

RESUMEN

Recent studies have demonstrated that mesenchymal stem cells (MSC) exhibit a tropism to tumors and form the tumor stroma. In addition, we found that MSC can secrete different types of factors. However, the involvement of MSC-derived factors in human tongue squamous cell carcinoma (TSCC) growth has not been clearly addressed. The CCN family includes multifunctional signaling molecules that affect the initiation and development events of various tumors. In our study, we report that CCN2/connective tissue growth factor (CTGF) was the most highly induced among the CCN family members in MSC that were co-cultured with TSCC cells. To evaluate the relationship between CCN2 and TSCC growth, we downregulated MSC-derived CCN2 expression with shRNA targeting CCN2 and found that MSC-secreted CCN2 promotes TSCC cell proliferation, migration and invasion. We also confirmed that MSC-derived CCN2 partially accelerated tumor growth in vitro. Taken together, these results suggest that MSC-derived CCN2 contributes to the promotion of proliferation, migration and invasion of TSCC cells and may be a possible therapy target in the future.


Asunto(s)
Carcinoma de Células Escamosas/genética , Movimiento Celular/genética , Proliferación Celular/genética , Factor de Crecimiento del Tejido Conjuntivo/genética , Células Madre Mesenquimatosas/metabolismo , Invasividad Neoplásica/genética , Neoplasias de la Lengua/genética , Carcinoma de Células Escamosas/patología , Línea Celular Tumoral , Regulación hacia Abajo/genética , Regulación Neoplásica de la Expresión Génica/genética , Humanos , Invasividad Neoplásica/patología , Neoplasias de la Lengua/patología
4.
J Transl Med ; 14: 26, 2016 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-26818837

RESUMEN

BACKGROUND: Metastasis to long distance organs is the main reason leading to morality of tongue squamous cell carcinoma (TSCC); however, the molecular mechanisms are still unknown. High mobility group AT-hook 2 (HMGA2) is highly expressed in multiple metastatic carcinomas, in which it contributes to cancer progression, metastasis and poor prognosis by upregulating Snail expression and inducing epithelial mesenchymal transition (EMT). This study focuses on investigating the role and mechanism of regulation of HMGA2 in the metastasis of TSCC. METHODS: HMGA2 mRNA and protein expression were examined in TSCC specimens by quantitative real-time polymerase chain reaction, western blotting and immunohistochemistry (IHC). Western blotting, IHC and immunofluorescence were also used to measure the expression and localization of EMT marker E-Cadherin and Vimentin both in TSCC cells and tissues. Knockdown assay was performed in vitro in TSCC cell lines using small interfering RNAs and the functional assay was carried out to determine the role of HMGA2 in TSCC cell migration and invasion. RESULTS: TSCC mRNA and protein expression were significantly up-regulated in tumor tissues when compared to adjacent non-tumor tissues, and the overexpression of HMGA2 was closely correlated with lymph nodes metastasis. Clinicopathological analysis indicated that HMGA2 expression was associated with clinical stage (P = 0.001), lymph node metastasis (P = 0.000), histological differentiation (P = 0.002) and survival (P = 0.000). Silencing the HMGA2 expression in Cal27 and UM1 resulted in the inhibition of cell migration and invasion, meanwhile down-regulation of HMGA2 impaired the phenotype of EMT in TSCC cell lines and tissues. The Multivariate survival analysis indicates that HMGA2 can be an independent prognosis biomarker in TSCC. CONCLUSION: Our findings demonstrate that HMGA2 promotes TSCC invasion and metastasis; additionally, HMGA2 is an independent prognostic factor which implied that HMGA2 can be a biomarker both for prognosis and therapeutic target of TSCC.


Asunto(s)
Transición Epitelial-Mesenquimal/genética , Proteína HMGA2/genética , Neoplasias de la Lengua/genética , Neoplasias de la Lengua/patología , Carcinogénesis/genética , Carcinogénesis/patología , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patología , Línea Celular Tumoral , Movimiento Celular/genética , Regulación hacia Abajo , Femenino , Regulación Neoplásica de la Expresión Génica , Técnicas de Silenciamiento del Gen , Proteína HMGA2/metabolismo , Humanos , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Análisis Multivariante , Invasividad Neoplásica , Fenotipo , Pronóstico , Factores de Riesgo , Factores de Transcripción de la Familia Snail , Factores de Transcripción/metabolismo , Regulación hacia Arriba/genética
5.
J Asian Nat Prod Res ; 16(4): 418-21, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24597720

RESUMEN

A new periplogenin cardenolide, periplogulcoside (1), together with three known cardenolides, was isolated from the seeds of Antiaris toxicaria. The structure of the new compound was characterized as periplogenin-3-O-ß-D-glucopyranosyl-(1 → 4)-ß-D-glucopyranoside (1) by spectroscopic methods including 1D and 2D NMR, HR-TOF-MS, and CD spectrometry, and the known compounds were identified by comparison of their NMR and HR-TOF-MS data with those reported in the literature. Compound 1 showed significant cytotoxicity against Hela and HepG-2 cell lines.


Asunto(s)
Antiaris/química , Antineoplásicos Fitogénicos/aislamiento & purificación , Cardenólidos/aislamiento & purificación , Medicamentos Herbarios Chinos/aislamiento & purificación , Antineoplásicos Fitogénicos/química , Antineoplásicos Fitogénicos/farmacología , Cardenólidos/química , Cardenólidos/farmacología , Ensayos de Selección de Medicamentos Antitumorales , Medicamentos Herbarios Chinos/química , Medicamentos Herbarios Chinos/farmacología , Células HeLa , Células Hep G2 , Humanos , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Extractos Vegetales/química , Semillas/química
6.
Hu Li Za Zhi ; 61(4): 26-34, 2014 Aug.
Artículo en Zh | MEDLINE | ID: mdl-25116312

RESUMEN

BACKGROUND: Skin care is an important responsibility of nurse aides in long-term care facilities, and the nursing knowledge, attitudes, and skills of these aides significantly affects quality of care. However, the work schedule of nurse aides often limits their ability to obtain further education and training. Therefore, developing appropriate and effective training programs for nurse aides is critical to maintaining and improving quality of care in long-term care facilities. PURPOSE: This study investigates the effects of multimedia assisted instruction on the skin care learning of nurse aides working in long-term care facilities. METHODS: A quasi-experimental design and convenient sampling were adopted in this study. Participants included 96 nurse aides recruited from 5 long-term care facilities in Taoyuan County, Taiwan. The experimental group received 3 weeks of multimedia assisted instruction. The control group did not receive this instruction. The Skin Care Questionnaire for Nurse Aides in Long-term Care Facilities and the Skin Care Behavior Checklist were used for assessment before and after the intervention. RESULTS: (1) Posttest scores for skin care knowledge, attitudes, behavior, and the skin care checklist were significantly higher than pretest scores for the intervention group. There was no significant difference between pretest and posttest scores for the control group. (2) A covariance analysis of pretest scores for the two groups showed that the experimental group earned significantly higher average scores than their control group peers for skin care knowledge, attitudes, behavior, and the skin care checklist. CONCLUSIONS: The multimedia assisted instruction demonstrated significant and positive effects on the skin care leaning of nurse aides in long-term care facilities. This finding supports the use of multimedia assisted instruction in the education and training of nurse aides in long-term care facilities in the future.


Asunto(s)
Evaluación Educacional/estadística & datos numéricos , Multimedia , Asistentes de Enfermería/educación , Cuidados de la Piel/enfermería , Humanos , Aprendizaje , Cuidados a Largo Plazo , Asistentes de Enfermería/psicología , Investigación en Educación de Enfermería , Investigación en Evaluación de Enfermería , Taiwán
7.
Pediatr Neonatol ; 65(3): 298-302, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38453564

RESUMEN

BACKGROUND: The endoscopic surgery for persistent muscular torticollis has been well-described and most are subcutaneous working caverns. As the sternocleidomastoid muscle is located beneath the deep cervical fascia that corresponds to the pectoral fascia, this study aimed to review our results of the transaxillary approach under the pectoral fascia and the deep cervical fascia. METHODS: Between November 2009 and January 2022, pediatric patients with persistent muscular torticollis receiving transaxillary endoscopic subfascial operation were retrospectively reviewed and analyzed. RESULTS: There were thirty-three consecutive patients with median age of 6.5 years (range, 5.5 months-15.7 years). The median operating time was 90.0 min. With a median follow-up of 14.8 months (range, 5.0-127.7), the final outcomes showed excellent-to-good results in 90.9%, fair results in 6.1%, and poor results in 3.0%. Univariate analysis revealed that the long-term outcomes of the operation were independent of gender, age, involved side and previously open myotomy (p = 0.662, 0.818, 0.740 and 0.596, respectively). CONCLUSIONS: The subfascial working cavern would be technically achievable for the transaxillary endoscopic approach with good functional and cosmetic outcomes.


Asunto(s)
Endoscopía , Tortícolis , Humanos , Estudios Retrospectivos , Masculino , Femenino , Niño , Tortícolis/cirugía , Preescolar , Adolescente , Lactante , Endoscopía/métodos , Taiwán , Resultado del Tratamiento , Axila , Miotomía/métodos
8.
J Clin Med ; 13(6)2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38541914

RESUMEN

(1) Background: Either pre-operative physical status or unstable hemodynamic changes has been reported to play a potential role in causing vital organ dysfunction. Therefore, we intended to investigate the impact of the American Society of Anesthesiologist (ASA) classification and intraoperative hemodynamic instability on non-surgical complications following orthopedic surgery. (2) Methods: We collected data on 6478 patients, with a mean age of 57.3 ± 16, who underwent orthopedic surgeries between 2018 and 2020. The ASA classification and hemodynamic data were obtained from an anesthesia database. Non-surgical complications were defined as a dysfunction of the vital organs. (3) Results: ASA III/IV caused significantly higher odds ratios (OR) of 17.49 and 40.96, respectively, than ASA I for developing non-surgical complications (p < 0.001). Non-surgical complications were correlated with a 20% reduction in systolic blood pressure (SBP), which was intraoperatively compared to the pre-operative baseline ((OR) = 1.38, p = 0.02). The risk of postoperative complications increased with longer durations of SBP < 100 mmHg, peaking at over 20 min ((OR) = 1.33, p = 0.34). (4) Conclusions: Extended intraoperative hypotension and ASA III/IV caused a significantly higher risk of adverse events occurring within the major organs. The maintenance of hemodynamic stability prevents non-surgical complications after orthopedic surgeries.

9.
Am J Chin Med ; 52(4): 1173-1193, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38938156

RESUMEN

Heat shock proteins (HSPs), which function as chaperones, are activated in response to various environmental stressors. In addition to their role in diverse aspects of protein production, HSPs protect against harmful protein-related stressors. Calycosin exhibits numerous beneficial properties. This study aims to explore the protective effects of calycosin in the heart under heat shock and determine its underlying mechanism. H9c2 cells, western blot, TUNEL staining, flow cytometry, and immunofluorescence staining were used. The time-dependent effects of heat shock analyzed using western blot revealed increased HSP expression for up to 2[Formula: see text]h, followed by protein degradation after 4[Formula: see text]h. Hence, a heat shock damage duration of 4[Formula: see text]h was chosen for subsequent investigations. Calycosin administered post-heat shock demonstrated dose-dependent recovery of cell viability. Under heat shock conditions, calycosin prevented the apoptosis of H9c2 cells by upregulating HSPs, suppressing p-JNK, enhancing Bcl-2 activation, and inhibiting cleaved caspase 3. Calycosin also inhibited Fas/FasL expression and activated cell survival markers (p-PI3K, p-ERK, p-Akt), indicating their cytoprotective properties through PI3K/Akt activation and JNK inhibition. TUNEL staining and flow cytometry confirmed that calycosin reduced apoptosis. Moreover, calycosin reversed the inhibitory effects of quercetin on HSF1 and Hsp70 expression, illustrating its role in enhancing Hsp70 expression through HSF1 activation during heat shock. Immunofluorescence staining demonstrated HSF1 translocation to the nucleus following calycosin treatment, emphasizing its cytoprotective effects. In conclusion, calycosin exhibits pronounced protective effects against heat shock-induced damages by modulating HSP expression and regulating key signaling pathways to promote cell survival in H9c2 cells.


Asunto(s)
Apoptosis , Supervivencia Celular , Proteínas de Choque Térmico , Isoflavonas , Apoptosis/efectos de los fármacos , Isoflavonas/farmacología , Supervivencia Celular/efectos de los fármacos , Animales , Ratas , Proteínas de Choque Térmico/metabolismo , Proteínas de Choque Térmico/genética , Respuesta al Choque Térmico/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Línea Celular , Células Cultivadas , Caspasa 3/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo
10.
J Funct Biomater ; 14(3)2023 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-36976048

RESUMEN

This in vitro experiment aimed to understand the difference in preload acting on an abutment screw under different angles of angulated screw-retained crown and the performance after cyclic loading. In total, thirty implants with angulated screw channel (ASC) abutments were divided into two parts. The first part consisted of three groups: a 0° access channel with a zirconia crown (ASC-0) (n = 5), a 15° access channel with a specially designed zirconia crown (sASC-15) (n = 5), and a 25° access channel with a specially designed zirconia crown (sASC-25) (n = 5). The reverse torque value (RTV) was measured at 0° for each specimen. The second part consisted of three groups: a 0° access channel with a zirconia crown (ASC-0) (n = 5); a 15° access channel with a zirconia crown (ASC-15) (n = 5), and a 25° access channel with a zirconia crown (ASC-25) (n = 5). The manufacturer's recommended torque was applied to each specimen, and baseline RTV was measured before cyclic loading. Each ASC implant assembly was cyclically loaded at 0 to 40 N with 1 million cycles at 10 Hz. RTV was measured after cyclic loading. Kruskal-Wallis test and Jonckheere-Terpstra test were used for statistical analysis. All specimens were examined under a digital microscope and scanning electron microscope (SEM) to observe the wear of the screw head before and after the whole experiment. A significant difference in the different percentages of straight RTV (sRTV) between the three groups was found (p = 0.027). The angle of ASC to the different percentages of sRTV showed a significant linear trend (p = 0.003). No significant differences were found in RTV difference after cyclic loading among the ASC-0, ASC-15, and ASC-25 groups (p = 0.212). The ASC-25 group had the most serious degree of wear based on a digital microscope and SEM examination. The ASC angle will affect the actual preload acting on a screw: the larger the ASC angle, the smaller the preload. The performance of the angled ASC groups in RTV difference was comparable to that of 0° ASC after cyclic loading.

11.
J Funct Biomater ; 14(10)2023 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-37888180

RESUMEN

The type of implant-abutment connection is one of the factors influencing the distribution of occlusal forces. This study aims to investigate the biomechanical performance of the mandibular all-on-4 treatment with different implant-abutment connections. Two connection types with 30° abutments and 18-mm implant fixtures were chosen for the posterior implants of the all-on-4 assembly. For the external hexagon connection (EHC) group, the implants with 4 mm in diameter were used. For the internal hexagon connection (IHC) group, we selected implants with 4.3 mm in diameter. A vertical force of 190 N was applied to the cantilever region. The FEA results indicated that the most stressed region in the two groups was prosthetic screws, followed by multi-unit abutments (MUAs). The lowest values of von Mises stress were both observed on the bone. The peak stress value of the implant screw and implant fixture in the EHC group were 37.75% and 33.03% lower than the IHC group, respectively. For stress distribution patterns, the load force tended to be concentrated at locations where components were interconnected. The EHC and IHC are clinically durable under the tested loading conditions, but the prosthetic screws and MUAs can be the weak point on the posterior implant within the mandibular all-on-four assembly. The peak stress values of implant screw and implant fixture in the EHC groups were lower than the IHC group.

12.
Cell Biosci ; 13(1): 184, 2023 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-37784089

RESUMEN

BACKGROUND: CD24+CK19+/CD24+SOX9+ resident liver cells are activated and expanded after chronic liver injury in a ductular reaction. However, the sources and functions of these cells in liver damage remain disputed. RESULTS: The current study combined genetic lineage tracing with in vitro small-molecule-based reprogramming to define liver progenitor cells (LPCs) derived from hepatic parenchymal and non-parenchymal tissues. tdTom+ hepatocytes were isolated from ROSA26tdTomato mice following AAV8-Tbg-Cre-mediated recombination, EpCAM+ biliary epithelial cells (BECs) from wild-type intrahepatic bile ducts and ALB/GFP-EpCAM- cells were isolated from AlbCreERT/R26GFP mice. A cocktail of small molecules was used to convert the isolated cells into LPCs. These in vitro cultured LPCs with CD24 and SOX9 expression regained the ability to proliferate. Transcriptional profiling showed that the in-vitro cultured LPCs derived from the resident LPCs in non-parenchymal tissues expressed Lipocalin-2 (Lcn2) at high levels. Accordingly, endogenous Cd24a+Lcn2+ LPCs were identified by integration of sc-RNA-sequencing and pathological datasets of liver dysfunction which indicates that LPCs produced by ductular reactions might also originate from the resident LPCs. Transplantation of in-vitro cultured Cd24a+Lcn2+ LPCs into CCl4-induced fibrotic livers exacerbated liver damage and dysfunction, possibly due to LCN2-dependent macrophage inflammatory response. CONCLUSIONS: CD24+LCN2+ LPCs constituted the expanding ductular reaction and contributed to macrophage-mediated inflammation in chronic liver damage. The current findings highlight the roles of LPCs from distinct origins and expose the possibility of targeting LPCs in the treatment of chronic hepatic diseases.

13.
Proc Natl Acad Sci U S A ; 106(26): 10564-9, 2009 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-19541643

RESUMEN

Shear-induced melting and crystallization were investigated by confocal microscopy in concentrated colloidal suspensions of hard-sphere-like particles. Both silica and polymethylmethacrylate suspensions were sheared with a constant rate in either a countertranslating parallel plate shear cell or a counterrotating cone-plate shear cell. These instruments make it possible to track particles undergoing shear for extended periods of time in a plane of zero velocity. Although on large scales, the flow profile deviated from linearity, the crystal flowed in an aligned sliding layer structure at low shear rates. Higher shear rates caused the crystal to shear melt, but, contrary to expectations, the transition was not sudden. Instead, although the overall order decreased with shear rate, this was due to an increase in the nucleation of localized domains that temporarily lost and regained their ordered structure. Even at shear rates that were considered to have melted the crystal as a whole, ordered regions kept showing up at times, giving rise to very large fluctuations in 2D bond-orientational order parameters. Low shear rates induced initially disordered suspensions to crystallize. This time, the order parameter increased gradually in time without large fluctuations, indicating that shear-induced crystallization of hard spheres does not proceed via a nucleation and growth mechanism. We conclude that the dynamics of melting and crystallization under shear differ dramatically from their counterparts in quiescent suspensions.


Asunto(s)
Microscopía Confocal/métodos , Polimetil Metacrilato/química , Dióxido de Silicio/química , Suspensiones/química , Coloides/química , Cristalización , Congelación , Cinética , Tamaño de la Partícula , Transición de Fase , Resistencia al Corte , Estrés Mecánico , Termodinámica , Viscosidad
15.
World J Gastrointest Oncol ; 14(4): 935-946, 2022 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-35582104

RESUMEN

BACKGROUND: DNA methylation is a part of epigenetic modification, that is closely related to the growth and development of colorectal cancer (CRC). Specific methylated genes and methylated diagnostic models of tumors have become current research focuses. The methylation status of circulating DNA in plasma might serve as a potential biomarker for CRC. AIM: To investigate genome-wide methylation pattern in early CRC using the Illumina Infinium Human Methylation 850K BeadChip. METHODS: The 850K Methylation BeadChip was used to analyze the genome-wide methylation status of early CRC patients (n = 5) and colorectal adenoma patients (n = 5). Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enrichment analyses were performed on the selected differentially methylated sites to further discover candidate methylation biomarkers in plasma. RESULTS: A total of 1865 methylated CpG sites with significant differences were detected, including 676 hypermethylated sites and 1189 hypomethylated sites. The distribution of these sites covered from the 1st to 22nd chromosomes and are mainly distributed on the gene body and gene promoter region. GO and KEGG enrichment analysis showed that the functions of these genes were related to biological regulation, molecular binding, transcription factor activity and signal transduction pathway. CONCLUSION: The study demonstrated that the Illumina Infinium Human Methylation 850K BeadChip can be used to investigate genome-wide methylation status of plasma DNA in early CRC and colorectal adenoma patients.

16.
Materials (Basel) ; 15(9)2022 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-35591628

RESUMEN

Residual alveolar ridge resorption often occurs after tooth extraction, which causes issues requiring further prothesis rehabilitation. A treatment concept referred to as all-on-four, involving fixed dentures supported with four implants, was recently developed. The current study aimed to determine the effect of changing bone atrophy and implant length in all-on-four treatments on stress and strain in the surrounding bone of the implant. A three-dimensional finite element method was used in this research. The stress analysis was conducted with von Mises stress values. Two types of synthetic jawbone models with mild and moderate atrophy were used. Furthermore, two different implant lengths with a similar implant design and diameter were selected, and they were classified into eight models. Then, the bone model was assessed via a computed tomography (CT) scan and was transformed into a virtual model in Geomagic and SolidWorks with implant rebuilding. After modifying bone atrophy, the von Mises stresses in the surrounding bone of the implant were as follows: mild type 2 < mild type 3 < moderate type 3 < moderate type 4. The bone quantity change rate increased more than when bone conditions were limited. Compared with changes in implant lengths, the stresses in the peri-implant surrounding bone were generally higher in the 9 mm implant length group than in the 11.5 mm group. However, the results did not significantly differ. In conclusion, the von Mises stress and strain increased in the models with moderate atrophy and low-density trabecular bone. Hence, bone atrophy and its presurgical diagnosis in long-term implant prognosis are crucial.

17.
Antioxidants (Basel) ; 11(7)2022 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-35883884

RESUMEN

Unlike other nuclear factor erythroid-2-related factor 2 (Nrf2) activators, the mechanism of action of curcumin analog, ASC-JM17 (JM17), in regulating oxidative homeostasis remains unknown. Spinocerebellar ataxia type 3 (SCA3) is an inherited polyglutamine neurodegenerative disease caused mainly by polyglutamine neurotoxicity and oxidative stress. Presently, we compared actions of JM17 with those of known Nrf2 activators, omaveloxolone (RTA-408) and dimethyl fumarate (DMF), using human neuroblastoma SK-N-SH cells with stable transfection of full-length ataxin-3 protein with 78 CAG repeats (MJD78) to clarify the resulting pathological mechanism by assaying mitochondrial function, mutant ataxin-3 protein toxicity, and oxidative stress. JM17, 1 µM, comprehensively restored mitochondrial function, decreased mutant protein aggregates, and attenuated intracellular/mitochondrial reactive oxygen species (ROS) levels. Although JM17 induced dose-dependent Nrf2 activation, a low dose of JM17 (less than 5 µM) still had a better antioxidant ability compared to the other Nrf2 activators and specifically increased mitochondrial superoxide dismutase 2 in an Nrf2-dependent manner as shown by knockdown experiments with siRNA. It showed that activation of Nrf2 in response to ROS generated in mitochondria could play an import role in the benefit of JM17. This study presents the diversified regulation of JM17 in a pathological process and helped develop more effective therapeutic strategies for SCA3.

18.
Materials (Basel) ; 15(17)2022 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-36079334

RESUMEN

Bone resorption around implants is quite common, and the maturity and popularization of computer-aided design and computer-aided manufacturing (CAD/CAM) technology have made the use of aftermarket abutment screws more widespread. This study aimed to explore the biomechanical influence of these two common factors on the internal stress of an implant system using three-dimensional finite element analysis (3D FEA). The FEA results indicated that under the same loading conditions, the use of an aftermarket screw had the greatest impact on the screw itself among the three components of the implant system, while the maximum stress increased by 6.3% and 10.5% in the bone integrity and bone loss models, respectively. Moreover, the marginal bone loss models had the greatest impact on the implant fixture, with a maximum stress increase of 51.8% on average. Evidently, the influence of bone loss might be far greater than that of the aftermarket screw; however, any factor could be enough to cause clinical failure. Therefore, we should pay more attention to the maintenance of the long-term peri-implant marginal bone integrity.

19.
Materials (Basel) ; 15(7)2022 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-35407988

RESUMEN

Three groups of zirconia abutments (n = 5) consisting of different connection designs or manufacturers were investigated (All-Zr, ASC-Zr, and AM-Zr groups). All-electric dynamic test instruments were used to place static loading on a specimen with a crosshead speed set at 1 mm/min. A Kruskal-Wallis test and a post hoc Mann-Whitney U test were used for statistical evaluation. The mean fracture resistance was 252.37 ± 82.79 N for the All-Zr group, 384.62 ± 45.24 N for ASC-Zr group, and 361.83 ± 90.31 N for the AM-Zr group. The difference of fracture resistance between the three groups was marginally significant (Kruskal-Wallis test, p = 0.054), with the ASC zirconia abutment tending to have higher fracture resistance than the full zirconia abutment. The modes of failure among the three types of abutments are different. The All-Zr group showed an oblique fracture line starting from the buccal aspect at the region of the implant platform. While the ASC-Zr and AM-Zr groups showed a relatively horizontal fracture line with a greater distance from the implant platform. The titanium inserts cannot significantly improve the fracture resistance of the zirconia abutment. However, they may alter the modes of failure, allowing buccal fracture surfaces of the zirconia abutments to be placed away from the implant platform, thereby protecting the implant-abutment connection.

20.
Int J Oral Maxillofac Implants ; 37(3): 485-493, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35727239

RESUMEN

PURPOSE: Poor alveolar bone quality and quantity may cause low insertion torque during implant placement; therefore, a delicate occlusal design is important for the immediate loading procedure. This retrospective clinical study aimed to investigate (1) the proportion of implants with a low insertion torque between the maxilla and mandible, (2) factors affecting implants with a low insertion torque, and (3) survival rates of implants with a low insertion torque value (< 35 Ncm) using different occlusal designs with full-arch fixed prostheses supported by immediately loaded implants. MATERIALS AND METHODS: Between 2013 and 2017, patients who received full-arch reconstructions were treated with immediately loaded one-piece fixed prostheses supported by four to six implants. Full-arch fixed prostheses with at least one immediately loaded regular implant with a low insertion torque value were included in this study. The fixed provisional acrylic prosthesis with a rigid framework was delivered within 3 to 5 days after surgery. According to the distribution of implants with low insertion torque, provisional prostheses were divided into three groups with different occlusal schemes. Definitive prostheses were fabricated after 3 months of loading. RESULTS: A total of 144 patients were treated; 608 and 304 regular implants were inserted in 118 maxillae and 76 mandibles, respectively. Moreover, 42 patients (11 men and 31 women) with 39 maxillae and 4 mandibles were included in this study. The proportion of implants with low insertion torque values in the maxilla was significantly greater than that in the mandible (10.5% vs 1.6%, respectively, P < .001). Implant length and low insertion torque value had no significant correlation (P = .948). Implants with a 3.3-mm diameter (narrow platform) had a greater proportion of low insertion torque values than 4-mm-wide implants (P = .002). Implants placed in a fresh socket had a greater proportion of insertion torque values ≥ 35 Ncm (P = .023). The overall cumulative implant survival rate was 98.6%. Groups 1, 2, and 3 had 14, 23, and 6 provisional prostheses, respectively. The survival rates for implants with insertion torque values < 35 Ncm and ≥ 35 Ncm were 98.4% and 98.7%, respectively, and were not significantly different (P = .866). All prostheses were still functioning during the mean follow-up of 3.7 ± 1.2 years. CONCLUSION: The high cumulative implant survival rate indicated that implants with a low insertion torque in immediately loaded full-arch provisional prostheses did not jeopardize the outcomes after a corresponding occlusal scheme was used.


Asunto(s)
Implantes Dentales , Carga Inmediata del Implante Dental , Implantación Dental Endoósea/métodos , Prótesis Dental de Soporte Implantado , Fracaso de la Restauración Dental , Femenino , Estudios de Seguimiento , Humanos , Carga Inmediata del Implante Dental/métodos , Masculino , Estudios Retrospectivos , Torque , Resultado del Tratamiento
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA