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[PMID]:28471354
[Au] Autor:Li D; Jacobsen MM; Gyune Rim N; Backman D; Kaplan DL; Wong JY
[Ad] Endereço:Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, MA 02215, United States of America.
[Ti] Título:Introducing biomimetic shear and ion gradients to microfluidic spinning improves silk fiber strength.
[So] Source:Biofabrication;9(2):025025, 2017 May 31.
[Is] ISSN:1758-5090
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Silkworm silk is an attractive biopolymer for biomedical applications due to its high mechanical strength and biocompatibility; as a result, there is increasing interest in scalable devices to spin silk and recombinant silk so as to improve and customize their properties for diverse biomedical purposes (Vepari and Kaplan 2007 Prog. Polym. Sci. 32 ). While artificial spinning of regenerated silk fibroins adds tunability to properties such as degradation rate and surface functionalization, the resulting fibers do not yet approach the mechanical strength of native silkworm silk. These drawbacks reduce the applicability and attractiveness of artificial silk (Kinahan et al 2011 Biomacromolecules 12 ). Here, we used computational fluid dynamic simulations to incorporate shear in tandem with biomimetic ion gradients by coupling a modular novel glass microfluidic device to our previous co-axial flow device. Fibers spun with this combined apparatus demonstrated a significant increase in mechanical strength compared to fibers spun with the basic apparatus alone, with a three-fold increase in Young's modulus and extensibility and a twelve-fold increase in toughness. These results thus demonstrate the critical importance of ionic milieu and shear stress in spinning strong fibers from solubilized silk fibroin.
[Mh] Termos MeSH primário: Biomimética/métodos
Microfluídica/métodos
Seda/química
Resistência à Tração
[Mh] Termos MeSH secundário: Animais
Fenômenos Biomecânicos
Biomimética/instrumentação
Simulação por Computador
Hidrodinâmica
Íons
Metais/química
Microfluídica/instrumentação
Espectroscopia de Infravermelho com Transformada de Fourier
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Ions); 0 (Metals); 0 (Silk)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170505
[St] Status:MEDLINE
[do] DOI:10.1088/1758-5090/aa711b


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[PMID]:29267670
[Au] Autor:Bellan MC; Cunha PFJSD; Tavares JG; Spohr AM; Mota EG
[Ad] Endereço:Pontifícia Universidade Católica da Universidade Federal do Rio Grande do Sul - PUC-RS, School of Dentistry, Graduate Program, Porto Alegre, RS, Brazil.
[Ti] Título:Microtensile bond strength of CAD/CAM materials to dentin under different adhesive strategies.
[So] Source:Braz Oral Res;31:e109, 2017 Dec 18.
[Is] ISSN:1807-3107
[Cp] País de publicação:Brazil
[La] Idioma:eng
[Ab] Resumo:The present study aimed to evaluate the microtensile bond strength (µTBS) of novel computer-aided design/computer-aided manufacturing (CAD/CAM) restorative materials to dentin using different adhesive strategies. Thirty-two crowns were milled using CAD/CAM materials (Vita Mark II as control, Vita Suprinity, Vita Enamic and Lava Ultimate) and luted to dentin using different resin cements (RelyX ARC, RelyX Unicem 2 and RelyX Ultimate). The specimens were stored in 100% relative humidity at 37°C for 24 h and sectioned. The samples (n = 16) with cross-sectional areas of approximately 0.90 mm2, were submitted to a µTBS test in a universal testing machine with a crosshead speed of 0.5 mm/min. The samples were analyzed with SEM to determinate the failure mode. According to 2-way ANOVA and Tukey's test (α=0.05), the interaction effect (material x luting strategy) was significant (p=0.001). Regardless of the luting strategy, a higher µTBS was obtained with Lava Ultimate and Vita Enamic, which were significantly different from Vita Mark II and Vita Suprinity (p<0.05). For Vita Mark II, Vita Suprinity, Vita Enamic, and Lava Ultimate, the µTBS obtained with RelyX Unicem 2 was not significantly different from that obtained with RelyX ARC or RelyX Ultimate. All groups obtained at least three types of failure. The adhesive strategy with self-adhesive resin cement was comparable to conventional resin cement with total-etch or self-etch adhesive techniques in the bond of novel CAD/CAM materials to dentin.
[Mh] Termos MeSH primário: Cerâmica/química
Projeto Auxiliado por Computador
Colagem Dentária/métodos
Dentina/efeitos dos fármacos
Cimentos de Resina/química
[Mh] Termos MeSH secundário: Análise de Variância
Falha de Restauração Dentária
Dentina/química
Seres Humanos
Teste de Materiais
Microscopia Eletrônica de Varredura
Reprodutibilidade dos Testes
Propriedades de Superfície/efeitos dos fármacos
Resistência à Tração
Fatores de Tempo
[Pt] Tipo de publicação:EVALUATION STUDIES; JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Resin Cements)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180308
[Lr] Data última revisão:
180308
[Sb] Subgrupo de revista:D; IM
[Da] Data de entrada para processamento:171222
[St] Status:MEDLINE


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[PMID]:29412223
[Au] Autor:Genari B; Leitune VCB; Jornada DS; Aldrigui BR; Pohlmann AR; Guterres SS; Samuel SMW; Collares FM
[Ad] Endereço:Universidade Federal do Rio Grande do Sul - UFRGS, School of Dentistry, Dental Materials Laboratory, Porto Alegre, RS, Brazil.
[Ti] Título:Effect on adhesion of a nanocapsules-loaded adhesive system.
[So] Source:Braz Oral Res;32:e008, 2018 Feb 01.
[Is] ISSN:1807-3107
[Cp] País de publicação:Brazil
[La] Idioma:eng
[Ab] Resumo:This study aimed to evaluate the in situ degree of conversion, contact angle, and immediate and long-term bond strengths of a commercial primer and an experimental adhesive containing indomethacin- and triclosan-loaded nanocapsules (NCs). The indomethacin- and triclosan-loaded NCs, which promote anti-inflammatory and antibacterial effects through controlled release, were incorporated into the primer at a concentration of 2% and in the adhesive at concentrations of 1, 2, 5, and 10%. The in situ degree of conversion (DC, n=3) was evaluated by micro-Raman spectroscopy. The contact angle of the primer and adhesive on the dentin surface (n = 3) was determined by an optical tensiometer. For the microtensile bond strength µTBS test (12 teeth per group), stick-shaped specimens were tested under tensile stress immediately after preparation and after storage in water for 1 year. The data were analyzed using two-way ANOVA, three-way ANOVA and Tukey's post hoc tests with α=0.05. The use of the NC-loaded adhesive resulted in a higher in situ degree of conversion. The DC values varied from 75.07 ± 8.83% to 96.18 ± 0.87%. The use of NCs in only the adhesive up to a concentration of 5% had no influence on the bond strength. The contact angle of the primer remained the same with and without NCs. The use of both the primer and adhesive with NCs (for all concentrations) resulted in a higher contact angle of the adhesive. The longitudinal µTBS was inversely proportional to the concentration of NCs in the adhesive system, exhibiting decreasing values for the groups with primer containing NCs and adhesives with increasing concentrations of NCs. Adhesives containing up to 5% of nanocapsules and primer with no NCs maintained the in situ degree of conversion, contact angle, and immediate and long-term bond strengths. Therefore, the NC-loaded adhesive can be an alternative method for combining the bond performance and therapeutic effects. The use of an adhesive with up to 5% nanocapsules containing indomethacin and triclosan and a primer with no nanocapsules maintained the long-term bond performance.
[Mh] Termos MeSH primário: Colagem Dentária/métodos
Indometacina/química
Nanocápsulas/química
Cimentos de Resina/química
Triclosan/química
[Mh] Termos MeSH secundário: Análise de Variância
Animais
Bovinos
Falha de Restauração Dentária
Dentina/efeitos dos fármacos
Teste de Materiais
Transição de Fase/efeitos dos fármacos
Polimerização/efeitos dos fármacos
Valores de Referência
Reprodutibilidade dos Testes
Análise Espectral Raman
Propriedades de Superfície/efeitos dos fármacos
Resistência à Tração
Fatores de Tempo
[Pt] Tipo de publicação:EVALUATION STUDIES; JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Nanocapsules); 0 (Resin Cements); 4NM5039Y5X (Triclosan); 90881-69-9 (Scotchbond); XXE1CET956 (Indomethacin)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180307
[Lr] Data última revisão:
180307
[Sb] Subgrupo de revista:D; IM
[Da] Data de entrada para processamento:180208
[St] Status:MEDLINE


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[PMID]:27775924
[Au] Autor:Im SH; Jung Y; Jang Y; Kim SH
[Ad] Endereço:KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Korea. Biomaterials Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.
[Ti] Título:Poly(L-lactic acid) scaffold with oriented micro-valley surface and superior properties fabricated by solid-state drawing for blood-contact biomaterials.
[So] Source:Biofabrication;8(4):045010, 2016 10 24.
[Is] ISSN:1758-5090
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Most biomaterials composed of biodegradable polymers will contact either accidentally or consistently with blood and this commonly requires both good  mechanical strength and blood compatibility. Despite this demand, current processing methods still make it difficult and complex to simultaneously improve the two properties. To overcome present limitations, the aim of this work is to develop a solid-state drawing which is a novel method for blood-contact biomaterials that can simultaneously improve the two essential factors of mechanical strength and blood compatibility, as well as induce a micro-patterned surface. Solid-state drawn (SSD) poly(L-lactic acid) (PLLA) film significantly maximally increased tensile strength and elastic modulus about ninefold and sixfold, respectively, compared to undrawn film. Furthermore, it was determined that SSD-PLLA film had highly developed molecular orientation, higher crystallinity and surface hydrophobicity. Additionally, the SSD method could greatly reduce roughness of the surface and induce the formation of aligned valleys, forming microstructures on the film surface. The topographical cue delayed hydrolytic degradation and prevented damage on the surface by NaOH of alkali compounds are compared with undrawn film. In energy-dispersive x-ray spectroscopy analysis, the surface of SSD film treated by NaOH was not detected on any ions whereas undrawn film held foreign ions on surface defects. The hemolysis rate of SSD film was considerably decreased with an increase of draw ratio up to 0.2% maximally and SSD film has shown greatly lower platelet adhesion compared to undrawn film in blood-compatibility analysis. Interestingly, one-directional alignment of micro-valley structure on SSD film could promote initial adhesion of human umbilical vein endothelial cells (HUVEC) compared with undrawn film and guide the direction of HUVEC. In conclusion, the newly designed SSD method has shown potential for developing blood-contact biomaterials simply due to great mechanical properties, blood compatibility and an aligned micro-patterned surface.
[Mh] Termos MeSH primário: Materiais Biocompatíveis/química
Poliésteres/química
[Mh] Termos MeSH secundário: Materiais Biocompatíveis/farmacologia
Plaquetas/citologia
Varredura Diferencial de Calorimetria
Adesão Celular/efeitos dos fármacos
Módulo de Elasticidade
Eritrócitos/citologia
Eritrócitos/efeitos dos fármacos
Hemólise/efeitos dos fármacos
Células Endoteliais da Veia Umbilical Humana
Seres Humanos
Microscopia de Força Atômica
Espectrometria por Raios X
Propriedades de Superfície
Resistência à Tração
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Biocompatible Materials); 0 (Polyesters); 459TN2L5F5 (poly(lactide))
[Em] Mês de entrada:1711
[Cu] Atualização por classe:180308
[Lr] Data última revisão:
180308
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161025
[St] Status:MEDLINE


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[PMID]:28749741
[Au] Autor:Edgar CM; Singh H; Obopilwe E; Voss A; Divenere J; Tassavor M; Comer B; Sanchez G; Mazzocca AD; Provencher MT
[Ad] Endereço:Department of Orthopaedic Surgery, New England Musculoskeletal Institute, University of Connecticut School of Medicine, Farmington, Connecticut, USA.
[Ti] Título:Pectoralis Major Repair: A Biomechanical Analysis of Modern Repair Configurations Versus Traditional Repair Configuration.
[So] Source:Am J Sports Med;45(12):2858-2863, 2017 Oct.
[Is] ISSN:1552-3365
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Pectoralis major (PM) ruptures are increasingly common, and a variety of surgical techniques have been described. However, tested techniques have demonstrated diminished strength with inadequate restoration of the footprint and suture failure at relatively low loads. Purpose/Hypothesis: The purpose was to biomechanically compare PM transosseous suture repair (current gold standard) to modern PM repair techniques that use larger caliber sutures, suture tape, and unicortical button fixation (UBF). The null hypothesis was that there would be no mechanical difference between repair techniques and no difference in the amount of footprint restoration. STUDY DESIGN: Controlled laboratory study. METHODS: Twenty-four fresh-frozen cadaveric shoulders controlled for age and bone mineral density were randomized equally to 4 groups: (1) UBF, suture tape; (2) UBF, No. 5 suture, suture tape; (3) bone trough with No. 2 suture; and (4) native PM tendon group; all groups were tested to failure. The specimens were tested under cycling loads (10 N to 125 N) with a final load-to-failure test at 1 mm/s. Failure modes were classified by location and cause of rupture based on optical markers, while tendon footprint length was measured to determine amount of footprint restoration. RESULTS: For fixation strength, the mean peak load was significantly greater in the native tendon (1816 ± 706 N) versus UBF/No. 5 suture/suture tape (794 ± 168 N), UBF/suture tape (502 ± 201 N), and bone trough (492 ± 151 N) ( P < .001 for all). UBF/No. 5 suture/suture tape featured the lowest displacement superiorly (1.09 ± 0.47 mm) and inferiorly (1.14 ± 0.39 mm) with a significant difference compared with bone trough. With regard to tendon footprint reapproximation, cortical button fixation best approximated native tendon footprint length versus bone trough. CONCLUSION: Based on peak failure load, the UBF/No. 5 suture/suture tape construct demonstrated 61% greater construct strength than a traditional bone trough technique. Moreover, displacement after cyclic loading was by far smallest in the UBF/No. 5 suture/suture tape construct. Therefore, repair constructs with larger caliber suture and suture tape provide a measurable improvement in construct strength versus traditional PM repair techniques in a biomechanical model and may be advantageous for repair. CLINICAL RELEVANCE: Cortical button fixation with larger caliber suture and suture tape allows for a significantly better PM repair than more traditional techniques at the time of surgery, which may ultimately result in improved clinical outcomes if implemented in surgical practice.
[Mh] Termos MeSH primário: Procedimentos Ortopédicos/métodos
Músculos Peitorais/fisiologia
Músculos Peitorais/cirurgia
Ruptura/cirurgia
[Mh] Termos MeSH secundário: Idoso
Fenômenos Biomecânicos
Cadáver
Feminino
Seres Humanos
Masculino
Meia-Idade
Músculos Peitorais/lesões
Ruptura/fisiopatologia
Âncoras de Sutura
Técnicas de Sutura
Resistência à Tração
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180306
[Lr] Data última revisão:
180306
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170728
[St] Status:MEDLINE
[do] DOI:10.1177/0363546517716175


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[PMID]:29324868
[Au] Autor:Choi HMC; Cheing AKK; Ng GYF; Cheing GLY
[Ad] Endereço:Department of Rehabilitation Sciences, Faculty of Health and Social Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
[Ti] Título:Effects of pulsed electromagnetic field (PEMF) on the tensile biomechanical properties of diabetic wounds at different phases of healing.
[So] Source:PLoS One;13(1):e0191074, 2018.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The present study investigated the effects of pulsed electromagnetic field (PEMF) on the tensile biomechanical properties of diabetic wounds at different phases of healing. Two intensities of PEMF were adopted for comparison. We randomly assigned 111 10-week-old male streptozotocin-induced diabetic Sprague-Dawley rats to two PEMF groups and a sham control group. Six-millimetre biopsy punched full thickness wounds were made on the lateral side of their hindlimbs. The PEMF groups received active PEMF delivered at 25 Hz with intensity of either 2 mT or 10 mT daily, while the sham group was handled in a similar way except they were not exposed to PEMF. Wound tissues were harvested for tensile testing on post-wounding days 3, 5, 7, 10, 14 and 21. Maximum load, maximum stress, energy absorption capacity, Young's modulus and thickness of wound tissue were measured. On post-wounding day 5, the PEMF group that received 10-mT intensity had significantly increased energy absorption capacity and showed an apparent increase in the maximum load. However, the 10-mT PEMF group demonstrated a decrease in Young's modulus on day 14. The 10-mT PEMF groups showed a significant increase in the overall thickness of wound tissue whereas the 2-mT group showed a significant decrease in the overall maximum stress of the wounds tissue. The present findings demonstrated that the PEMF delivered at 10 mT can improve energy absorption capacity of diabetic wounds in the early healing phase. However, PEMF (both 2-mT and 10-mT) seemed to impair the material properties (maximum stress and Young's modulus) in the remodelling phase. PEMF may be a useful treatment for promoting the recovery of structural properties (maximum load and energy absorption capacity), but it might not be applied at the remodelling phase to avoid impairing the recovery of material properties.
[Mh] Termos MeSH primário: Diabetes Mellitus Experimental/fisiopatologia
Campos Eletromagnéticos
Resistência à Tração
Ferimentos e Lesões/fisiopatologia
[Mh] Termos MeSH secundário: Animais
Fenômenos Biomecânicos
Masculino
Ratos
Ratos Sprague-Dawley
Estreptozocina
Ferimentos e Lesões/complicações
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
5W494URQ81 (Streptozocin)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180223
[Lr] Data última revisão:
180223
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180112
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0191074


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[PMID]:29339160
[Au] Autor:Raudsepp A; Kent LM; Hall SB; Williams MAK
[Ad] Endereço:Institute of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand.
[Ti] Título:Overstretching partially alkyne functionalized dsDNA using near infrared optical tweezers.
[So] Source:Biochem Biophys Res Commun;496(3):975-980, 2018 02 12.
[Is] ISSN:1090-2104
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The force-extension behaviour of synthesized double-stranded DNAs (dsDNAs) designed to have 2.1% or 6.6% of the thymine bases alkyne functionalized was studied using near infrared (NIR) optical tweezers. Measurements were carried out on substrates with and without flurophores covalently attached to the alkyne moiety over an extended force range (F=0-70 pN) and results were compared to those obtained from an unmodified control. In accordance with earlier work [1] (measured over a force range F=0-5 pN), the force-extension of the dsDNA containing 2.1% modified-bases agreed well with that of the control. By contrast, the force-extension of the dsDNA containing 6.6% modified-bases showed an increasing deviation from that of the control as the dsDNA extension approached the molecule's contour length. These results indicate that incorporating alkyne functionalized bases can modify the mechanical properties of the dsDNA and that degree of functionalization should be carefully considered if a fluorescent mechanical analogue is required. A discrepancy between 1) the control dsDNA force-extension measured in Ref. [1] and that measured here and 2) dsDNA extensions carried out on the same duplex at different laser powers was noted; this was attributed to beam heating by the NIR trapping laser which was estimated to raise the local temperature at the optical traps by ΔT≈10-15°C.
[Mh] Termos MeSH primário: Alquinos/química
DNA/química
Pinças Ópticas
[Mh] Termos MeSH secundário: Módulo de Elasticidade
Raios Infravermelhos
Conformação de Ácido Nucleico
Estresse Mecânico
Resistência à Tração
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Alkynes); 9007-49-2 (DNA)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180222
[Lr] Data última revisão:
180222
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180118
[St] Status:MEDLINE


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[PMID]:29037702
[Au] Autor:Benbettaïeb N; Tanner C; Cayot P; Karbowiak T; Debeaufort F
[Ad] Endereço:Univ. Bourgogne Franche-Comté/Agrosup Dijon, UMR PAM A02-102, Food and Wine Physical-Chemistry Lab, 1 esplanade Erasme, 21000 Dijon, France; IUT-Dijon-Auxerre, Dpt BioEngineering, 7 blvd Docteur Petitjean, 20178 Dijon Cedex, France.
[Ti] Título:Impact of functional properties and release kinetics on antioxidant activity of biopolymer active films and coatings.
[So] Source:Food Chem;242:369-377, 2018 Mar 01.
[Is] ISSN:0308-8146
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:This work deals with the study of the release kinetics of some natural antioxidants (ferulic acid, caffeic acid and tyrosol) from chitosan-fish gelatin edible films immersed ethanol at 96%, as well as the kinetics of their antioxidant activity using the DPPH assay. The aim was to determine how film functional properties influence the release kinetic and antioxidant activity. The addition of antioxidants to chitosan-fish gelatin matrix decreased the water vapour permeability by more than 30%. The tensile strength (TS) increased up to 50% after the incorporation of antioxidants. Some molecular interactions between polymer chains and antioxidants were confirmed by FTIR where spectra displayed a shift of the amide-III peak. Films containing caffeic acid or a caffeic-ferulic acid mixture exhibited the highest radical scavenging activity, leading to a 90% antioxidant activity at equilibrium but the release rate controlled the efficacy of the system.
[Mh] Termos MeSH primário: Antioxidantes/análise
Biopolímeros/química
Quitosana/química
Gelatina/química
[Mh] Termos MeSH secundário: Antioxidantes/química
Ácidos Cafeicos/análise
Ácidos Cafeicos/química
Ácidos Cumáricos/análise
Ácidos Cumáricos/química
Produtos Pesqueiros
Cinética
Permeabilidade
Álcool Feniletílico/análogos & derivados
Álcool Feniletílico/análise
Álcool Feniletílico/química
Resistência à Tração
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Antioxidants); 0 (Biopolymers); 0 (Caffeic Acids); 0 (Coumaric Acids); 1AK4MU3SNX (4-hydroxyphenylethanol); 9000-70-8 (Gelatin); 9012-76-4 (Chitosan); AVM951ZWST (ferulic acid); ML9LGA7468 (Phenylethyl Alcohol); U2S3A33KVM (caffeic acid)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180222
[Lr] Data última revisão:
180222
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171018
[St] Status:MEDLINE


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[PMID]:29274784
[Au] Autor:Miyazawa A; Ito S; Asano S; Tanaka I; Sato M; Kondo M; Hasegawa Y
[Ad] Endereço:Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan.
[Ti] Título:Regulation of PD-L1 expression by matrix stiffness in lung cancer cells.
[So] Source:Biochem Biophys Res Commun;495(3):2344-2349, 2018 01 15.
[Is] ISSN:1090-2104
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Expression of programmed death-ligand 1 (PD-L1) in tumor cells such as lung cancer cells plays an important role in mechanisms underlying evasion of an immune check point system. Lung cancer tissue with increased deposition of extracellular matrix is much stiffer than normal lung tissue. There is emerging evidence that the matrix stiffness of cancer tissue affects the phenotypes and properties of cancer cells. Nevertheless, the effects of substrate rigidity on expression of PD-L1 in lung cancer cells remain elusive. We evaluated the effects of substrate stiffness on PD-L1 expression in HCC827 lung adenocarcinoma cells by using polyacrylamide hydrogels with stiffnesses of 2 and 25 kPa. Expression of PD-L1 protein was higher on the stiffer substrates (25 kPa gel and plastic dish) than on the soft 2 kPa gel. PD-L1 expression was reduced by detachment of cells adhering to the substrate. Interferon-γ enhanced expression of PD-L1 protein cultured on stiff (25 kPa gel and plastic dishes) and soft (2 kPa gel) substrates and in the cell adhesion-free condition. As the stiffness of substrates increased, formation of actin stress fiber and cell growth were enhanced. Transfection of the cells with short interfering RNA for PD-L1 inhibited cell growth without affecting stress fiber formation. Treatment of the cells with cytochalasin D, an inhibitor of actin polymerization, significantly reduced PD-L1 protein levels. Taken together, a stiff substrate enhanced PD-L1 expression via actin-dependent mechanisms in lung cancer cells. It is suggested that stiffness as a tumor environment regulates PD-L1 expression, which leads to evasion of the immune system and tumor growth.
[Mh] Termos MeSH primário: Antígeno B7-H1/metabolismo
Matriz Extracelular/metabolismo
Neoplasias Pulmonares/fisiopatologia
Fibras de Estresse/metabolismo
[Mh] Termos MeSH secundário: Linhagem Celular Tumoral
Força Compressiva
Módulo de Elasticidade
Matriz Extracelular/patologia
Regulação Neoplásica da Expressão Gênica
Dureza
Seres Humanos
Neoplasias Pulmonares/patologia
Fibras de Estresse/fisiologia
Estresse Mecânico
Resistência à Tração
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (B7-H1 Antigen); 0 (CD274 protein, human)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180214
[Lr] Data última revisão:
180214
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171225
[St] Status:MEDLINE


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[PMID]:28470459
[Au] Autor:Smolen C; Quenneville CE
[Ad] Endereço:Department of Mechanical Engineering, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4L7, Canada.
[Ti] Título:A Finite Element Model of the Foot/Ankle to Evaluate Injury Risk in Various Postures.
[So] Source:Ann Biomed Eng;45(8):1993-2008, 2017 08.
[Is] ISSN:1573-9686
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The foot/ankle complex is frequently injured in many types of debilitating events, such as car crashes. Numerical models used to assess injury risk are typically minimally validated and do not account for ankle posture variations that frequently occur during these events. The purpose of this study was to evaluate a finite element model of the foot and ankle accounting for these positional changes. A model was constructed from computed tomography scans of a male cadaveric lower leg and was evaluated by comparing simulated bone positions and strain responses to experimental results at five postures in which fractures are commonly reported. The bone positions showed agreement typically within 6° or less in all anatomical directions, and strain matching was consistent with the range of errors observed in similar studies (typically within 50% of the average strains). Fracture thresholds and locations in each posture were also estimated to be similar to those reported in the literature (ranging from 6.3 kN in the neutral posture to 3.9 kN in combined eversion and external rotation). The least vulnerable posture was neutral, and all other postures had lower fracture thresholds, indicating that examination of the fracture threshold of the lower limb in the neutral posture alone may be an underestimation. This work presents an important step forward in the modeling of lower limb injury risk in altered ankle postures. Potential clinical applications of the model include the development of postural guidelines to minimize injury, as well as the evaluation of new protective systems.
[Mh] Termos MeSH primário: Fraturas do Tornozelo/fisiopatologia
Traumatismos do Pé/fisiopatologia
Modelos Biológicos
Postura
Medição de Risco/métodos
Ossos do Tarso/lesões
Ossos do Tarso/fisiopatologia
[Mh] Termos MeSH secundário: Cadáver
Força Compressiva
Simulação por Computador
Módulo de Elasticidade
Análise de Elementos Finitos
Seres Humanos
Masculino
Meia-Idade
Amplitude de Movimento Articular
Estresse Mecânico
Resistência à Tração
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180215
[Lr] Data última revisão:
180215
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170505
[St] Status:MEDLINE
[do] DOI:10.1007/s10439-017-1844-2



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