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1.
Eur Rev Med Pharmacol Sci ; 25(2): 779-786, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33577032

RESUMO

OBJECTIVE: The aim of this study was to analyze the biological effects of circ-0079593 and its potential mechanism in the progression of melanoma. PATIENTS AND METHODS: Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was carried out to detect circ-0079593 expression in melanoma tissue samples and cell lines, and the relationship between circ-0079593 expression and prognosis of patients with melanoma was analyzed based on collected clinical information. Then, the melanoma cell line stably overexpressing circ-0079593 was constructed using lentiviral stable transfection technique, and then, Cell Counting Kit-8 (CCK-8) and transwell assays were carried out to detect the proliferation rate, migration, as well as invasion abilities of melanoma cells, respectively. In addition, the potential binding targets of circ-0079593 were searched through bioinformatics analysis, and the results were verified by Dual-Luciferase assay. RESULTS: It was found that, in comparison with the normal control group, circ-0079593 showed a significantly high expression in melanoma tissues and cell lines, which predicted a poor prognosis of melanoma patients. In vitro experiments showed that the overexpression of circ-0079593 remarkably enhanced proliferation rate, as well as invasion ability of melanoma cells. Moreover, bioinformatics data analysis revealed that there exist binding sites of microRNA-433 both in circ-0079593 and EGFR. Meanwhile, the results of the Luciferase assay confirmed that circ-0079593 probably bound to microRNA-433, as an endogenous competitive RNA (ceRNA), to regulate EGFR expression. At last, cell reverse experiments demonstrated that the overexpression of microRNA-433 could attenuate the capacity of melanoma cells to proliferate and migrate, while simultaneous overexpression of circ-0079593 partially restored those cell functions. CONCLUSIONS: In melanoma, circ-0079593 may serve as a cancer-promoting gene to accelerate the rates of cell proliferation and migration, which may exert its effects by elevating EGFR expression by binding to microRNA-433.


Assuntos
Melanoma/metabolismo , MicroRNAs/metabolismo , RNA Circular/metabolismo , Neoplasias Cutâneas/metabolismo , Movimento Celular , Proliferação de Células , Células Cultivadas , Receptores ErbB/genética , Receptores ErbB/metabolismo , Humanos , Melanoma/patologia , MicroRNAs/genética , RNA Circular/genética , Neoplasias Cutâneas/patologia
2.
J Mech Behav Biomed Mater ; 103: 103590, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32090919

RESUMO

In recent years, mesh structures have attracted significant interest for structural and functional applications. However, the mechanical strength and energy absorption ability of uniform mesh structured materials degrade with density. To address this challenge, we propose the concept of functionally graded mesh structures. The objective of the proposed research is to fundamentally understand the compressive behavior of graded mesh structures. The compression-compression fatigue behavior of functionally graded Ti-6Al-4V mesh structure under identical bulk stress condition is studied here. During cyclic deformation, it was observed that the local stress distribution in the struts was not uniform because of inhomogeneous mechanical properties of the constituents. Fatigue cracks first initiated in the lowest strength constituent, and then propagated until structural failure occurred. However, no obvious damage was observed in other constituents during the entire process. In contrast with iso-strain state, the fatigue life of graded structure is mainly determined by the constituent with the lowest strength.


Assuntos
Telas Cirúrgicas , Titânio , Elétrons , Teste de Materiais , Próteses e Implantes
3.
Nat Commun ; 10(1): 1227, 2019 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-30862795

RESUMO

The original version of this Article omitted the author Kuan Wang, who is from the 'College of Biomedical Engineering, Taipei Medical University, Taipei 11031, Taiwan' and 'Nanyang Environment & Water Research Institute, Nanyang Technological University, Singapore 637141, Singapore.'Also, the author S.H. Lim was incorrectly given as L.S. Hoi and A. Larsson was incorrectly given as A. Larson.The "Author contributions" was amended to reflect the authorship changes. It previously read 'Y.Z.S., C.-W.Q., and A.Q.L. jointly conceived the idea. Y.Z.S., S.X., Y.Z., J.B.Z., W.S., J.H.W., T.N.C., Z.C.Y., Y.L.H., B.L., P.H.Y., D.P.T., and C.-W.Q. performed the numerical simulations and theoretical analysis. Y.Z.S., S.X., and L.K.C. did the fabrication and experiments of particle hopping, biomolecule binding and flow cytometry. A.L. and L.S.H. did the SPR experiments. S.X., Y.Z.S., Y.Z., C.-W.Q., Y.-Y.C., L.K.C., T.H.Z., and A.Q.L. prepared the manuscript. S.X., Y.Z., C.-W.Q., and A.Q.L. supervised and coordinated all the work. All authors commented on the manuscript.' The correct version states 'B.L., K. W., P.H.Y.' instead of 'B.L., P.H.Y.' and 'S.H.L.' in place of 'L.S.H.'This has been corrected in both the PDF and HTML versions of the Article.

4.
Eur Rev Med Pharmacol Sci ; 23(3): 1203-1213, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30779090

RESUMO

OBJECTIVE: Deregulated expression of miRNAs contributes to the development of acute myeloid leukemia (AML). miR-504-3p, one of these miRNAs, has been found have upregulated expression in various human malignancies. Our present study aimed to detect the expression of miR-504-3p and its biological effect in AML. PATIENTS AND METHODS: Real-time quantitative PCR was applied to evaluate the expression level of miR-504-3p in AML cell lines and the serum from AML cases. The correlations between miR-504-3p and AML patients' clinicopathological characteristics, as well as AML patients' overall survival, were statistically assessed. Moreover, we investigated the effect of miR-504-3p knockdown on AML cells by CCK-8, Transwell assays and flow cytometry, in vitro. The Western blot, RT-PCR and luciferase reporter assay were performed to evaluate the relationship between miR-504-3p and its downstream target genes. Finally, the biological function of MTHFD2 was also analyzed. RESULTS: The expression levels of miR-504-3p were significantly down-regulated in the serum of AML patients and cell lines, and its low expression was positively associated with advanced clinical stages and poor prognosis of AML patients. Functional assays indicated that overexpression of miR-504-3p leads to AML cell growth arrest, invasion and migration inhibition, and elevated rates of apoptosis. We also found that miR-504-3p regulated the expression of MTHFD2 by binding to its 3'-UTR, and knockdown of MTHFD2 significantly suppressed AML cells proliferation, migration and invasion, and promoted apoptosis. CONCLUSIONS: Our findings provide important evidence that supports the role of miR-504-3p as a tumor suppressor in AML via the inhibition of MTHFD2 expression.


Assuntos
Aminoidrolases/economia , Regulação Neoplásica da Expressão Gênica , Genes Supressores de Tumor , Leucemia Mieloide Aguda/genética , Metilenotetra-Hidrofolato Desidrogenase (NADP)/economia , MicroRNAs/genética , Enzimas Multifuncionais/economia , Regiões 3' não Traduzidas , Apoptose/genética , Estudos de Casos e Controles , Linhagem Celular Tumoral , Proliferação de Células/genética , Células HL-60 , Humanos , Leucemia Mieloide Aguda/mortalidade , Leucemia Mieloide Aguda/patologia , Análise de Sobrevida , Células THP-1 , Regulação para Cima
5.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 53(8): 566-571, 2018 Aug 09.
Artigo em Chinês | MEDLINE | ID: mdl-30078274

RESUMO

Chemotherapy is one of the effective methods to treat cancer. However, the chemotherapy agents may cause a series of adverse reactions due to the nonselective characteristics that affect not only tumor cells, but also normal cells. Oral mucositis induced by chemotherapy is a common oral complication caused by chemotherapy in clinic. It brings great suffering to the patients and also interferes with the procedure of chemotherapy. Because of its high incidence in patients receiving chemotherapy and the significant influence, there are more researches on oral mucositis induced by chemotherapy which let us have further understanding of it. This review article will introduce the pathogenesis, risk factors, clinical manifestations, assessments, treatment and prevention of oral mucositis induced by chemotherapy.


Assuntos
Antineoplásicos/efeitos adversos , Estomatite/induzido quimicamente , Humanos , Neoplasias/tratamento farmacológico , Fatores de Risco , Estomatite/complicações , Estomatite/prevenção & controle
6.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 53(3): 191-194, 2018 Mar 09.
Artigo em Chinês | MEDLINE | ID: mdl-29972978

RESUMO

Objective: To investigate the clinical manifestations and pathological changes of benign lymphoadenosis of oral mucosa. Methods: The clinical data of 98 cases of benign lymphoadenosis of oral mucosa were analyzed. Results: The clinical manifestations of benign lymphoadenosis of oral mucosa included erosive ulcer (64%) and nodule (9%) and the rate of misdiagnosis was 98%. Neutrophil infiltration occurred in the epithelium of 51% cases and the lymphocyte was diffusely infiltrated in lamina propria of 83% cases. Conclusions: When the mucous membrane of the lamina propria is characterized by complex cell components, diffuse infiltrating lymphocytes and infiltration of neutrophils in mucosal epithelium without erosion and ulceration, it is necessary to highly suspect benign lymphoadenosis of oral mucosa. Finding the focal aggregation of lymphoid follicles or lymphocytes is helpful for the correct diagnosis.


Assuntos
Doenças Linfáticas/patologia , Doenças da Boca/patologia , Movimento Celular , Epitélio/patologia , Humanos , Doenças Linfáticas/diagnóstico , Doenças da Boca/diagnóstico , Mucosa Bucal/patologia , Neutrófilos
7.
Nat Commun ; 9(1): 815, 2018 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-29483548

RESUMO

Particle trapping and binding in optical potential wells provide a versatile platform for various biomedical applications. However, implementation systems to study multi-particle contact interactions in an optical lattice remain rare. By configuring an optofluidic lattice, we demonstrate the precise control of particle interactions and functions such as controlling aggregation and multi-hopping. The mean residence time of a single particle is found considerably reduced from 7 s, as predicted by Kramer's theory, to 0.6 s, owing to the mechanical interactions among aggregated particles. The optofluidic lattice also enables single-bacteria-level screening of biological binding agents such as antibodies through particle-enabled bacteria hopping. The binding efficiency of antibodies could be determined directly, selectively, quantitatively and efficiently. This work enriches the fundamental mechanisms of particle kinetics and offers new possibilities for probing and utilising unprecedented biomolecule interactions at single-bacteria level.


Assuntos
Bactérias , Nanopartículas/química , Cinética , Técnicas Analíticas Microfluídicas/métodos
8.
J Biomater Appl ; 32(8): 1032-1048, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29249195

RESUMO

The objective of the study described here is to fundamentally elucidate the biological response of 3D printed Ti-6Al-4V alloy mesh structures that were surface modified to introduce titania nanotubes with an average pore size of ∼80 nm via an electrochemical anodization process from the perspective of enhancing bioactivity. The bioactivity of the mesh structures were analyzed through immersion test in simulated body fluid, which confirmed the nucleation and growth of fine globular nanoscale apatite on the nanoporous titania-modified (anodized) mesh structure surface, and agglomerated apatite with fine flakes of apatite crystals on as-fabricated mesh structure surface, that were rich in calcium and phosphorous. The cellular activity of bioactive anodized mesh structure was explored in terms of cell-material interactions involving adhesion, proliferation, synthesis of extracellular and intracellular proteins, differentiation, and mineralization. Cells adhered with a sheet-like morphology on as-fabricated mesh structure, whereas, on anodized mesh structure, numerous filopodia-like cellular extensions interacting with nanotube pores were observed. The formation of a bioactive nanoscale apatite, cell-nanotube interactions as imaged via electron microscopy, higher expression of proteins (actin, vinculin, fibronectin, and alkaline phosphatase (ALP)), and calcium content points toward the determining role of anodized mesh structure in modulating osteoblasts functions. The unique combination of nanoporous bioactive titania and interconnected porous architecture of anodized titanium alloy mesh structure provided a multimodal roughness surface ranging from nano to micro to macroscale, which helps in attaining strong primary and secondary fixation of the implant device along with the pathway for supply of nutrients and oxygen to cells and tissue.


Assuntos
Materiais Biocompatíveis/química , Regeneração Óssea , Nanotubos/química , Titânio/química , Ligas , Animais , Materiais Biocompatíveis/farmacologia , Regeneração Óssea/efeitos dos fármacos , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Eletrodos , Camundongos , Nanotubos/ultraestrutura , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Porosidade , Impressão Tridimensional , Propriedades de Superfície , Titânio/farmacologia
9.
Lab Chip ; 17(14): 2443-2450, 2017 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-28634603

RESUMO

An optofluidic chip is demonstrated in experiments for high-resolution and multi-range particle separation through the optically-induced microscopic vibration effect, where nanoparticles are trapped in loosely overdamped optical potential wells created with combined optical and fluidic constraints. It is the first demonstration of separating single nanoparticles with diameters ranging from 60 to 100 nm with a resolution of 10 nm. Nanoparticles vibrate with an amplitude of 3-7 µm in the loosely overdamped potential wells in the microchannel. The proposed optofluidic device is capable of high-resolution particle separation at both nanoscale and microscale without reconfiguring the device. The separation of bacteria from other larger cells is accomplished using the same chip and operation conditions. The unique trapping mechanism and the superb performance in high-resolution and multi-range particle separation of the proposed optofluidic chip promise great potential for a diverse range of biomedical applications.

10.
J Biomed Mater Res A ; 105(3): 859-870, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27885781

RESUMO

Titanium alloys (Ti-6Al-4V and Ti-6Al-7Nb) are widely used for implants, which are characterized by high elastic modulus (∼110 GPa) with (α + ß) structure and that may induce undesirable stress shielding effect and immune responses associated with the presence of toxic elements. In this regard, we have combined the attributes of a new alloy design and the concept of additive manufacturing to fabricate 3D scaffolds with an interconnected porous structure. The new alloy is a ß-type Ti-24Nb-4Zr-8Sn (Ti2448) alloy with significantly reduced modulus. In the present study, we explore the biological response of electron beam melted low modulus Ti2448 alloy porous mesh structure through the elucidation of bioactivity and osteoblast functions. The cellular activity was explored in terms of cell-to-cell communication involving proliferation, spreading, synthesis of extracellular and intracellular proteins, differentiation, and mineralization. The formation of fine apatite-like crystals on the surface during immersion test in simulated body fluid confirmed the bioactivity of the scaffold surface, which provided the favorable osteogenic microenvironment for cell-material interaction. The combination of unique surface chemistry and interconnected porous architecture provided the desired pathway for supply of nutrients and oxygen to cells and a favorable osteogenic micro-environment for incorporation (on-growth and in-growth) of osteoblasts. The proliferation and differentiation of pre-osteoblasts and their ability to form a well mineralized bone-like extracellular matrix (ECM) by secreting bone markers (ALP, calcium, etc.) over the struts of the scaffold point toward the determining role of unique surface chemistry and 3D architecture of the Ti2448 alloy mesh structure in modulating osteoblasts functions. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 859-870, 2017.


Assuntos
Ligas , Calcificação Fisiológica/efeitos dos fármacos , Implantes Experimentais , Teste de Materiais , Osteoblastos/metabolismo , Telas Cirúrgicas , Ligas/química , Ligas/farmacologia , Animais , Linhagem Celular , Matriz Extracelular/metabolismo , Camundongos , Osteoblastos/citologia , Porosidade
11.
Colloids Surf B Biointerfaces ; 150: 78-88, 2017 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-27888725

RESUMO

We elucidate here the osteoblasts functions and cellular activity in 3D printed interconnected porous architecture of functionally gradient Ti-6Al-4V alloy mesh structures in terms of cell proliferation and growth, distribution of cell nuclei, synthesis of proteins (actin, vinculin, and fibronectin), and calcium deposition. Cell culture studies with pre-osteoblasts indicated that the interconnected porous architecture of functionally gradient mesh arrays was conducive to osteoblast functions. However, there were statistically significant differences in the cellular response depending on the pore size in the functionally gradient structure. The interconnected porous architecture contributed to the distribution of cells from the large pore size (G1) to the small pore size (G3), with consequent synthesis of extracellular matrix and calcium precipitation. The gradient mesh structure significantly impacted cell adhesion and influenced the proliferation stage, such that there was high distribution of cells on struts of the gradient mesh structure. Actin and vinculin showed a significant difference in normalized expression level of protein per cell, which was absent in the case of fibronectin. Osteoblasts present on mesh struts formed a confluent sheet, bridging the pores through numerous cytoplasmic extensions. The gradient mesh structure fabricated by electron beam melting was explored to obtain fundamental insights on cellular activity with respect to osteoblast functions.


Assuntos
Ligas/química , Materiais Biocompatíveis/química , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Titânio/química , Células 3T3 , Actinas/biossíntese , Animais , Regeneração Óssea , Substitutos Ósseos , Cálcio/química , Adesão Celular , Núcleo Celular/metabolismo , Proliferação de Células , Células Cultivadas , Fibronectinas/biossíntese , Teste de Materiais/métodos , Camundongos , Porosidade , Pós , Próteses e Implantes , Propriedades de Superfície , Vinculina/biossíntese
12.
Dent Mater ; 33(2): 152-165, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27889088

RESUMO

OBJECTIVES: Low modulus ß-titanium alloys with non-toxic alloying elements are envisaged to provide good biocompatibility and alleviate the undesired stress shielding effect. The objective of this study is to fundamentally elucidate the biological response of novel high strength-low elastic modulus Ti2448 alloy through the study of bioactivity and osteoblast cell functions. METHODS: Characterization techniques such as SEM, EDX, XRD, and fluorescence microscopy were utilized to analyze the microstructure, morphology, chemical composition, and cell adhesion. The cellular activity was explored in terms of cell-to-cell communication involving proliferation, spreading, synthesis of extracellular and intracellular proteins, differentiation, and mineralization. RESULTS: The formation of fine apatite-like crystals on the surface during immersion test in simulated body fluid confirmed the bioactivity of the surface, which provided the favorable osteogenic microenvironment for cell-material interaction. The proliferation and differentiation of pre-osteoblasts and their ability to form a well mineralized bone-like extracellular matrix (ECM) by secreting bone markers (ALP, calcium, etc.) over the surface point toward the determining role of unique surface chemistry and surface properties of the Ti-24Nb-4Zr-8Sn (Ti2448) alloy in modulating osteoblasts functions. SIGNIFICANCE: These results demonstrated that the low modulus (∼49GPa) Ti2448 alloy with non-toxic alloying elements can be used as a potential dental or orthopedic load-bearing implant material.


Assuntos
Ligas , Módulo de Elasticidade , Osteoblastos , Materiais Biocompatíveis , Teste de Materiais , Propriedades de Superfície , Titânio
13.
J Biomed Mater Res A ; 104(10): 2488-501, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27225062

RESUMO

The objective of the study is to fundamentally elucidate the biological response of 3D printed mesh structures subjected to plasma electrolytic oxidation process through the study of osteoblast functions. The cellular activity of plasma electrolytic-oxidized mesh structure was explored in terms of cell-to-cell communication involving proliferation, synthesis of extracellular and intracellular proteins, and mineralization. Upon plasma electrolytic oxidation of the mesh structure, a thin layer of bioactive titania with pore size 1-3 µm was nucleated on the surface. The combination of microporous bioactive titania and interconnected porous architecture provided the desired pathway for supply of nutrients and oxygen to cells and tissue and a favorable osteogenic microenvironment for tissue on-growth and in-growth, in relation to the unmodified mesh structure. The formation of a confluent layer as envisaged via electron microscopy and quantitative assessment of the expression level of proteins (actin, vinculin, and fibronectin) point toward the determining role of surface-modified mesh structure in modulating osteoblasts functions. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2488-2501, 2016.


Assuntos
Ligas/metabolismo , Alumínio/metabolismo , Materiais Biocompatíveis/metabolismo , Osteoblastos/citologia , Titânio/metabolismo , Vanádio/metabolismo , Ligas/química , Alumínio/química , Animais , Materiais Biocompatíveis/química , Comunicação Celular , Linhagem Celular , Proliferação de Células , Matriz Extracelular/metabolismo , Camundongos , Osteoblastos/metabolismo , Oxirredução , Porosidade , Titânio/química , Vanádio/química
14.
Zhonghua Xin Xue Guan Bing Za Zhi ; 44(5): 416-20, 2016 May 24.
Artigo em Chinês | MEDLINE | ID: mdl-27220577

RESUMO

OBJECTIVE: In this study, the sreening of candidate pathogenic gene is done among family members of an dilated cardiomyopathy(DCM)and hypertrophic cardiomyopathy (HCM) coexistence, and find the relationship between the genotype and the phenotype. METHODS: The inheritance atlas was drawn, analysis of genetic characteristics and clinical phenotype.Peripheral venous blood samples of proband and family members were candidated gene exon high-throughput sequencing sub target capture, make the result compares with related database, ultimately screening the target area of the exon and mutations of candidate genes and then using bidirectional sequencing of Sanger to sequence other family members and the health group which were matching with gender and age to testify whether there is the above mutations. RESULTS: In this family, the proband and his father carry three missense mutations, about TTNc.604 A>G(p.Lys202Glu)、TAZ c. 580A>G(p.Ile194Val)and MYH7c.730 T>C(p.Phe244Leu). The heart function of proband was failure, and accompanied malignant arrhythmia.But his father has no obvious clinical symptoms.In this family, the same genetic mutation of disease causing gene lead to different clinical phenotype, but different genetic mutation of disease causing gene lead to the same clinical phenotype.None of the mutations found in this family was found in the health group. CONCLUSION: The patient of this family carries the genetic mutation of MYH7, TTN and TAZ.The patient of this family carries the composite mutation of MYH7(+) /TTN(+) heterozygous missense mutation and TAZ(+) /TTN(+) heterozygous missense mutation may be show the performance of the genetic characteristics of early onset, severe phenotype.


Assuntos
Cardiomiopatia Dilatada/genética , Cardiomiopatia Hipertrófica/genética , Testes Genéticos , Aciltransferases , Miosinas Cardíacas/genética , China , Conectina/genética , Éxons , Genótipo , Humanos , Masculino , Mutação de Sentido Incorreto , Cadeias Pesadas de Miosina/genética , Linhagem , Fenótipo , Fatores de Transcrição/genética
15.
J Mech Behav Biomed Mater ; 59: 251-264, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26878293

RESUMO

Additive manufacturing technique is a promising approach for fabricating cellular bone substitutes such as trabecular and cortical bones because of the ability to adjust process parameters to fabricate different shapes and inner structures. Considering the long term safe application in human body, the metallic cellular implants are expected to exhibit superior fatigue property. The objective of the study was to study the influence of cell shape on the compressive fatigue behavior of Ti-6Al-4V mesh arrays fabricated by electron beam melting. The results indicated that the underlying fatigue mechanism for the three kinds of meshes (cubic, G7 and rhombic dodecahedron) is the interaction of cyclic ratcheting and fatigue crack growth on the struts, which is closely related to cumulative effect of buckling and bending deformation of the strut. By increasing the buckling deformation on the struts through cell shape design, the cyclic ratcheting rate of the meshes during cyclic deformation was decreased and accordingly, the compressive fatigue strength was increased. With increasing bending deformation of struts, fatigue crack growth in struts contributed more to the fatigue damage of meshes. Rough surface and pores contained in the struts significantly deteriorated the compressive fatigue strength of the struts. By optimizing the buckling and bending deformation through cell shape design, Ti-6Al-4V alloy cellular solids with high fatigue strength and low modulus can be fabricated by the EBM technique.


Assuntos
Teste de Materiais , Próteses e Implantes , Titânio/química , Ligas , Força Compressiva , Elétrons , Humanos , Propriedades de Superfície
16.
J Biomater Appl ; 30(8): 1182-204, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26637443

RESUMO

We describe here the combined efforts of engineering and biological sciences as a systemic approach to fundamentally elucidate osteoblast functions in functionally graded Ti-6Al-4 V mesh structures in relation to uniform/monolithic mesh arrays. First, the interconnecting porous architecture of functionally graded mesh arrays was conducive to cellular functions including attachment, proliferation, and mineralization. The underlying reason is that the graded fabricated structure with cells seeded from the large pore size side provided a channel for efficient transfer of nutrients to other end of the structure (small pore size), leading to the generation of mineralized extracellular matrix by differentiating pre-osteoblasts. Second, a comparative and parametric study indicated that gradient mesh structure had a pronounced effect on cell adhesion and mineralization, and strongly influenced the proliferation phase. High intensity and near-uniform distribution of proteins (actin and vinculin) on struts of the gradient mesh structure (cells seeded from large pore side) implied signal transduction during cell adhesion and was responsible for superior cellular activity, in comparison to the uniform mesh structure and non-porous titanium alloy. Cells adhered to the mesh struts by forming a sheet, bridging the pores through numerous cytoplasmic extensions, in the case of porous mesh structures. Intercellular interaction in porous structures provided a pathway for cells to communicate and mature to a differentiated phenotype. Furthermore, the capability of cells to migrate through the interconnecting porous architecture on mesh structures led to colonization of the entire structure. Cells were embedded layer-by-layer in the extracellular matrix as the matrix mineralized. The outcomes of the study are expected to address challenges associated with the treatment of segmental bone defects and bone-remodeling through favorable modulation of cellular response. Moreover, the study provides a foundation for a new branch of functionally graded materials with interconnected porous architecture.


Assuntos
Substitutos Ósseos/química , Osteoblastos/citologia , Titânio/química , Ligas , Animais , Substitutos Ósseos/metabolismo , Adesão Celular , Movimento Celular , Proliferação de Células , Matriz Extracelular/metabolismo , Teste de Materiais , Camundongos , Osteoblastos/metabolismo , Porosidade , Propriedades de Superfície , Titânio/metabolismo
17.
Acta Biomater ; 10(10): 4537-47, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24969664

RESUMO

Ti-6Al-4V reticulated meshes with different elements (cubic, G7 and rhombic dodecahedron) in Materialise software were fabricated by additive manufacturing using the electron beam melting (EBM) method, and the effects of cell shape on the mechanical properties of these samples were studied. The results showed that these cellular structures with porosities of 88-58% had compressive strength and elastic modulus in the range 10-300MPa and 0.5-15GPa, respectively. The compressive strength and deformation behavior of these meshes were determined by the coupling of the buckling and bending deformation of struts. Meshes that were dominated by buckling deformation showed relatively high collapse strength and were prone to exhibit brittle characteristics in their stress-strain curves. For meshes dominated by bending deformation, the elastic deformation corresponded well to the Gibson-Ashby model. By enhancing the effect of bending deformation, the stress-strain curve characteristics can change from brittle to ductile (the smooth plateau area). Therefore, Ti-6Al-4V cellular solids with high strength, low modulus and desirable deformation behavior could be fabricated through the cell shape design using the EBM technique.


Assuntos
Força Compressiva , Teste de Materiais , Telas Cirúrgicas , Titânio/química , Ligas
18.
Acta Biomater ; 10(6): 2866-75, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24583159

RESUMO

The use of nanostructuring to improve the stability of passive thin films on biomaterials can enhance their effectiveness in corrosion resistance and reduce the release of ions. The thickness of the ultrathin films that cover Ti and Ti alloys (only several nanometers) has prevented researchers from establishing systematic methods for their characterization. This study employed a multifunctional biomedical titanium alloy Ti-24Nb-4Zr-8Sn (wt.%) as a model material. Coarse-grained (CG) and nanostructured (NS) alloys were analyzed in 0.9% NaCl solution at 37°C. To reveal the details of the passive film, a method of sample preparation producing a passive layer suitable for transmission electron microscope analysis was developed. Electrochemical corrosion behavior was evaluated by potentiodynamic polarization tests and Mott-Schottky measurements. Surface depth chemical profile and morphology evolution were performed by X-ray photoelectron spectroscopy and in situ atomic force microscopy, respectively. A mechanism was proposed on the basis of the point defect model to compare the corrosion resistance of the passive film on NS and CG alloys. Results showed that the protective amorphous film on NS alloy is thicker, denser and more homogeneous with fewer defects than that on CG alloy. The film on NS alloy contains more oxygen and corrosion-resistant elements (Ti and Nb), as well as their suboxides, compared with the film on CG alloy. These characteristics can be attributed to the rapid, uniform growth of the passive film facilitated by nanostructuring.


Assuntos
Ligas , Modelos Biológicos , Nanoestruturas , Microscopia de Força Atômica , Microscopia Eletrônica de Transmissão , Espectroscopia Fotoeletrônica , Propriedades de Superfície
19.
J Intern Med ; 276(5): 512-24, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24528288

RESUMO

OBJECTIVE: Acquired aplastic anaemia (AA) is a T-cell-mediated, organ-specific autoimmune disease characterized by haematopoietic stem cell destruction in the bone marrow. The exact molecular mechanism of T-cell trafficking into the bone marrow is unclear in AA. Very late activation antigen-4 (VLA-4) and CX3C chemokine receptor 1 (CX3CR1) play active roles in many autoimmune diseases. Therefore, we investigated whether VLA-4 and CX3CR1 also contribute to T-cell migration into the bone marrow in acquired AA. DESIGN, SETTING AND SUBJECTS: Expression levels of CX3CR1 and VLA-4 and their ligands [fractalkine (CX3CL1) and vascular cell adhesion molecule-1 (VCAM-1)] were examined in 63 patients with AA and 21 healthy control subjects. T-cell chemotaxis and adhesion were analysed in 17 patients with severe AA. We also prospectively evaluated the expression pattern of CX3CR1 during treatment with antithymocyte globulin plus cyclosporine in 11 patients with severe AA. RESULTS: The proportion of peripheral and bone marrow CD4(+) and CD8(+) T cells expressing CX3CR1 and the level of CX3CL1 was increased in patients with AA. However, there was no significant difference in VLA-4 expression or VCAM-1 levels. Functional studies demonstrated that chemotaxis towards autologous bone marrow plasma or soluble CX3CL1 was significantly higher in T cells from AA patients and could be blocked by CX3CR1 inhibitors. CX3CR1-mediated T-cell adhesion was also upregulated in these patients. The expression of CX3CR1 was associated with the efficacy of immunosuppressive therapy. CONCLUSION: The present findings demonstrate that CX3CR1 plays a pivotal role in recruitment of T cells into the bone marrow in acquired AA and is a potential therapeutic target for treatment of this disorder.


Assuntos
Anemia Aplástica/imunologia , Medula Óssea/imunologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Quimiotaxia de Leucócito , Integrina alfa4beta1/metabolismo , Receptores de Quimiocinas/metabolismo , Anemia Aplástica/tratamento farmacológico , Anemia Aplástica/metabolismo , Soro Antilinfocitário/uso terapêutico , Medula Óssea/metabolismo , Receptor 1 de Quimiocina CX3C , Adesão Celular , Ciclosporina/uso terapêutico , Humanos , Imunossupressores/uso terapêutico , Integrina alfa4beta1/sangue , Estudos Prospectivos , Receptores de Quimiocinas/sangue , Molécula 1 de Adesão de Célula Vascular/sangue , Molécula 1 de Adesão de Célula Vascular/metabolismo
20.
Braz J Med Biol Res ; 47(2): 157-65, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24519132

RESUMO

Epidemiological studies of short and long sleepers have not been conducted previously. We collected socioeconomic, psychological, and polysomnographic characteristics of 6501 parents (3252 men and 3249 women) of 4036 primary school children in Guangzhou city. The study data were collected in three phases. The overall prevalence of short (5 h or less) and long (10 h or more) sleep duration was 0.52 and 0.64%, respectively. Long sleepers had higher Eysenck Personality Questionnaire neuroticism scores [odds ratio (OR)=1.224, 95% confidence interval (CI)=1.047-1.409] and lower education levels (OR=0.740, 95%CI=0.631-0.849) than short sleepers. In the polysomnographic assessment, short, long, and normal sleepers (7-8 h) shared similar durations of Stage 3 sleep (short=25.7±10.7, long=20.3±7.9, and normal=28.0±12.8 min, F=1.402, P=0.181). In daytime multiple sleep latency tests, short sleepers (10/19, 52.6%) were more prone to have a short sleep latency (≤ 8 min) than long sleepers (2/23, 8.7%). In addition to different sleep durations, neuroticism might also contribute to differences between short and long sleepers in social achievements. Stage 3 sleep might be essential for humans. The short sleep latency (≤ 8 min) of short sleepers in multiple sleep latency tests should be interpreted cautiously, since it was of the same severity as required for a diagnosis of narcolepsy or idiopathic hypersomnia.


Assuntos
Fases do Sono/fisiologia , Adulto , Criança , China , Estudos Epidemiológicos , Feminino , Humanos , Masculino , Polissonografia , Prevalência , Valores de Referência , Fatores Socioeconômicos , Inquéritos e Questionários
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