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[PMID]:28463576
[Au] Autor:Li K; Zhang C; Qiu L; Gao L; Zhang X
[Ad] Endereço:Tianjin Key Laboratory of Design and Intelligent Control of the Advanced Mechatronical System, School of Mechanical Engineering, Tianjin University of Technology , Tianjin, China .
[Ti] Título:Advances in Application of Mechanical Stimuli in Bioreactors for Cartilage Tissue Engineering.
[So] Source:Tissue Eng Part B Rev;23(4):399-411, 2017 Aug.
[Is] ISSN:1937-3376
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Articular cartilage (AC) is the weight-bearing tissue in diarthroses. It lacks the capacity for self-healing once there are injuries or diseases due to its avascularity. With the development of tissue engineering, repairing cartilage defects through transplantation of engineered cartilage that closely matches properties of native cartilage has become a new option for curing cartilage diseases. The main hurdle for clinical application of engineered cartilage is how to develop functional cartilage constructs for mass production in a credible way. Recently, impressive hyaline cartilage that may have the potential to provide capabilities for treating large cartilage lesions in the future has been produced in laboratories. The key to functional cartilage construction in vitro is to identify appropriate mechanical stimuli. First, they should ensure the function of metabolism because mechanical stimuli play the role of blood vessels in the metabolism of AC, for example, acquiring nutrition and removing wastes. Second, they should mimic the movement of synovial joints and produce phenotypically correct tissues to achieve the adaptive development between the micro- and macrostructure and function. In this article, we divide mechanical stimuli into three types according to forces transmitted by different media in bioreactors, namely forces transmitted through the liquid medium, solid medium, or other media, then we review and summarize the research status of bioreactors for cartilage tissue engineering (CTE), mainly focusing on the effects of diverse mechanical stimuli on engineered cartilage. Based on current researches, there are several motion patterns in knee joints; but compression, tension, shear, fluid shear, or hydrostatic pressure each only partially reflects the mechanical condition in vivo. In this study, we propose that rolling-sliding-compression load consists of various stimuli that will represent better mechanical environment in CTE. In addition, engineers often ignore the importance of biochemical factors to the growth and development of engineered cartilage. In our point of view, only by fully considering synergistic effects of mechanical and biochemical factors can we find appropriate culture conditions for functional cartilage constructs. Once again, rolling-sliding-compression load under appropriate biochemical conditions may be conductive to realize the adaptive development between the structure and function of engineered cartilage in vitro.
[Mh] Termos MeSH primário: Reatores Biológicos
[Mh] Termos MeSH secundário: Cartilagem
Cartilagem Articular
Condrócitos
Estresse Mecânico
Engenharia Tecidual
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180307
[Lr] Data última revisão:
180307
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE
[do] DOI:10.1089/ten.TEB.2016.0427


  2 / 59501 MEDLINE  
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[PMID]:28453731
[Au] Autor:Demolli S; Doddaballapur A; Devraj K; Stark K; Manavski Y; Eckart A; Zehendner CM; Lucas T; Korff T; Hecker M; Massberg S; Liebner S; Kaluza D; Boon RA; Dimmeler S
[Ad] Endereço:Institute for Cardiovascular Regeneration, Centre of Molecular Medicine, Goethe University, Theodor Stern Kai 7, 60590 Frankfurt, Germany.
[Ti] Título:Shear stress-regulated miR-27b controls pericyte recruitment by repressing SEMA6A and SEMA6D.
[So] Source:Cardiovasc Res;113(6):681-691, 2017 May 01.
[Is] ISSN:1755-3245
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Aims: Vessel maturation involves the recruitment of mural cells such as pericytes and smooth muscle cells. Laminar shear stress is a major trigger for vessel maturation, but the molecular mechanisms by which shear stress affects recruitment of pericytes are unclear. MicroRNAs (miRs) are small non-coding RNAs, which post-transcriptionally control gene expression. The aim of the present study was to unveil the mechanism by which shear stress-regulated microRNAs contribute to vessel maturation. Methods and results: Here, we show that laminar shear stress increased miR-27a and miR-27b expression in vitro and in ex vivo in mouse femoral artery explants. Overexpression of miR-27b in endothelial cells increased pericyte adhesion and pericyte recruitment in vitro. In vitro barrier function of endothelial-pericyte co-cultures was augmented by miR-27b overexpression, whereas inhibition of miR-27a/b reduced adhesion and pericyte coverage and decreased barrier functions. In vivo, pharmacological inhibition of miR-27a/b by locked nucleic acid antisense oligonucleotides significantly reduced pericyte coverage and increased water content in the murine uterus. MiR-27b overexpression repressed semaphorins (SEMA), which mediate repulsive signals, and the vessel destabilizing human but not mouse Angiopoietin-2 (Ang-2). Silencing of SEMA6A and SEMA6D rescued the reduced pericyte adhesion by miR-27 inhibition. Furthermore, inhibition of SEMA6D increased barrier function of an endothelial-pericyte co-culture in vitro. Conclusion: The present study demonstrates for the first time that shear stress-regulated miR-27b promotes the interaction of endothelial cells with pericytes, partly by repressing SEMA6A and SEMA6D.
[Mh] Termos MeSH primário: Encéfalo/irrigação sanguínea
Comunicação Celular
Movimento Celular
Células Endoteliais/metabolismo
Mecanotransdução Celular
Microvasos/metabolismo
Pericitos/metabolismo
Semaforinas/metabolismo
[Mh] Termos MeSH secundário: Animais
Células Cultivadas
Técnicas de Cocultura
Células Endoteliais da Veia Umbilical Humana/metabolismo
Seres Humanos
Camundongos
Camundongos Endogâmicos C57BL
MicroRNAs/genética
MicroRNAs/metabolismo
Interferência de RNA
Semaforinas/genética
Estresse Mecânico
Transfecção
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (MIRN27 microRNA, human); 0 (MicroRNAs); 0 (Mirn27 microRNA, mouse); 0 (SEMA6A protein, human); 0 (Sema6a protein, mouse); 0 (Sema6d protein, mouse); 0 (Semaphorins)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180308
[Lr] Data última revisão:
180308
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170429
[St] Status:MEDLINE
[do] DOI:10.1093/cvr/cvx032


  3 / 59501 MEDLINE  
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[PMID]:27771340
[Au] Autor:Ambrosini A; Gracia M; Proag A; Rayer M; Monier B; Suzanne M
[Ad] Endereço:LBCMCP UMR5088, Centre de Biologie Integrative (CBI), Université de Toulouse, CNRS, UPS, France.
[Ti] Título:Apoptotic forces in tissue morphogenesis.
[So] Source:Mech Dev;144(Pt A):33-42, 2017 04.
[Is] ISSN:1872-6356
[Cp] País de publicação:Ireland
[La] Idioma:eng
[Ab] Resumo:It is now well established that apoptosis is induced in response to mechanical strain. Indeed, increasing compressive forces induces apoptosis in confined spheroids of tumour cells, whereas releasing stress reduces apoptosis in spheroids cultivated in free suspension (Cheng et al., 2009). Apoptosis can also be induced by applying a 100 to 250MPa pressure, as shown in different cultured cells (for review, see (Frey et al., 2008)). During epithelium development, the pressure caused by a fast-growing clone can trigger apoptosis at the vicinity of the clone, mediating mechanical cell competition (Levayer et al., 2016). While the effect of strain has long been known for its role in apoptosis induction, the reciprocal mechanism has only recently been highlighted. First demonstrated at the cellular level, the effect of an apoptotic cell on its direct neighbours has been analysed in different kinds of monolayer epithelium (Gu et al., 2011; Rosenblatt et al., 2001; Kuipers et al., 2014; Lubkov & Bar-Sagi, 2014). More recently, the concept of a broader impact of apoptotic cell behaviours on tissue mechanical strain has emerged from the characterisation of tissue remodelling during Drosophila development (Toyama et al., 2008; Monier et al., 2015). In the present review, we summarize our current knowledge on the mechanical impact of apoptosis during tissue remodelling.
[Mh] Termos MeSH primário: Apoptose/genética
Drosophila melanogaster/crescimento & desenvolvimento
Células Epiteliais/citologia
Regulação da Expressão Gênica no Desenvolvimento
Morfogênese/genética
[Mh] Termos MeSH secundário: Abdome/crescimento & desenvolvimento
Animais
Divisão Celular
Proteínas de Ligação a DNA/genética
Proteínas de Ligação a DNA/metabolismo
Proteínas de Drosophila/genética
Proteínas de Drosophila/metabolismo
Drosophila melanogaster/genética
Drosophila melanogaster/metabolismo
Células Epiteliais/metabolismo
Matriz Extracelular/metabolismo
Larva/genética
Larva/crescimento & desenvolvimento
Larva/metabolismo
Modelos Biológicos
Pupa/genética
Pupa/crescimento & desenvolvimento
Pupa/metabolismo
Estresse Mecânico
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (DNA-Binding Proteins); 0 (Drosophila Proteins); 0 (dwg protein, Drosophila); 0 (reaper protein, Drosophila)
[Em] Mês de entrada:1712
[Cu] Atualização por classe:180302
[Lr] Data última revisão:
180302
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161025
[St] Status:MEDLINE


  4 / 59501 MEDLINE  
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[PMID]:29390319
[Au] Autor:Wang Y; Yi XD; Li CD
[Ad] Endereço:Department of Orthopedics, Peking University First Hospital, Beijing, China.
[Ti] Título:The influence of artificial nucleus pulposus replacement on stress distribution in the cartilaginous endplate in a 3-dimensional finite element model of the lumbar intervertebral disc.
[So] Source:Medicine (Baltimore);96(50):e9149, 2017 Dec.
[Is] ISSN:1536-5964
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:OBJECTIVE: This study aimed to investigate the effects involved with the artificial nucleus pulposus (NP) replacement on stress distribution of the cartilaginous endplate (CEP) in a 3-dimensional lumbar intervertebral disc (IVD) model using a finite element (FE) analysis. METHODS: A healthy male volunteer was recruited for the purposes of the study and a spiral computed tomography scan was subsequently conducted to obtain the data information in relation to the L4/5 motion segment. An FE model of the L4/5 motion segment constructed, on the basis of which degenerative IVD, IVD with NP removal, and IVD with NP replacement were in turn built. The stress distribution of the CEP and bulging of IVD were estimated using various motion states, including axial loading, forward flexion, backward extension, left axial rotation, and right axial rotation. RESULTS: Under different motion states, the vertebral stress was higher in the degenerative IVD, the IVD with NP removal, and the IVD with NP replacement, in comparison to that of the normal IVD. Furthermore, a higher vertebral stress was detected in the degenerative IVD than the IVD with NP removal and the IVD with NP replacement. An even distribution of vertebral stress was observed in the IVD model with an artificial NP replacement, while the vertebral stress and bulging displacement were lower than after NP removal. Our findings provided confirmation that stress of the CEP was consistent with the vertebral stress. CONCLUSION: This study provided evidence suggesting that NP replacement, vertebral stress, and bulging displacement are lower than that of degenerative IVD and IVD with NP removal under different motion states.
[Mh] Termos MeSH primário: Degeneração do Disco Intervertebral/cirurgia
Núcleo Pulposo/cirurgia
[Mh] Termos MeSH secundário: Fenômenos Biomecânicos
Simulação por Computador
Discotomia
Análise de Elementos Finitos
Voluntários Saudáveis
Seres Humanos
Imagem por Ressonância Magnética
Masculino
Modelos Anatômicos
Estresse Mecânico
Tomografia Computadorizada Espiral
Adulto Jovem
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180301
[Lr] Data última revisão:
180301
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:180203
[St] Status:MEDLINE
[do] DOI:10.1097/MD.0000000000009149


  5 / 59501 MEDLINE  
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[PMID]:29343708
[Au] Autor:Peck VL; Oakes RL; Harper EM; Manno C; Tarling GA
[Ad] Endereço:British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 0ET, UK. vlp@bas.ac.uk.
[Ti] Título:Pteropods counter mechanical damage and dissolution through extensive shell repair.
[So] Source:Nat Commun;9(1):264, 2018 01 17.
[Is] ISSN:2041-1723
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The dissolution of the delicate shells of sea butterflies, or pteropods, has epitomised discussions regarding ecosystem vulnerability to ocean acidification over the last decade. However, a recent demonstration that the organic coating of the shell, the periostracum, is effective in inhibiting dissolution suggests that pteropod shells may not be as susceptible to ocean acidification as previously thought. Here we use micro-CT technology to show how, despite losing the entire thickness of the original shell in localised areas, specimens of polar species Limacina helicina maintain shell integrity by thickening the inner shell wall. One specimen collected within Fram Strait with a history of mechanical and dissolution damage generated four times the thickness of the original shell in repair material. The ability of pteropods to repair and maintain their shells, despite progressive loss, demonstrates a further resilience of these organisms to ocean acidification but at a likely metabolic cost.
[Mh] Termos MeSH primário: Exoesqueleto/fisiologia
Ecossistema
Gastrópodes/fisiologia
Estresse Mecânico
[Mh] Termos MeSH secundário: Exoesqueleto/anatomia & histologia
Exoesqueleto/ultraestrutura
Animais
Gastrópodes/anatomia & histologia
Gastrópodes/ultraestrutura
Concentração de Íons de Hidrogênio
Microscopia Eletrônica de Varredura
Água do Mar/química
Microtomografia por Raio-X
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180227
[Lr] Data última revisão:
180227
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180119
[St] Status:MEDLINE
[do] DOI:10.1038/s41467-017-02692-w


  6 / 59501 MEDLINE  
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[PMID]:28455220
[Au] Autor:Lee HT; Kim HJ; Kim CS; Gomi K; Taya M; Nomura S; Ahn SH
[Ad] Endereço:Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 08826, Republic of Korea.
[Ti] Título:Site-specific characterization of beetle horn shell with micromechanical bending test in focused ion beam system.
[So] Source:Acta Biomater;57:395-403, 2017 Jul 15.
[Is] ISSN:1878-7568
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Biological materials are the result of years of evolution and possess a number of efficient features and structures. Researchers have investigated the possibility of designing biomedical structures that take advantage of these structural features. Insect shells, such as beetle shells, are among the most promising types of biological material for biomimetic development. However, due to their intricate geometries and small sizes, it is challenging to measure the mechanical properties of these microscale structures. In this study, we developed an in-situ testing platform for site-specific experiments in a focused ion beam (FIB) system. Multi-axis nano-manipulators and a micro-force sensor were utilized in the testing platform to allow better results in the sample preparation and data acquisition. The entire test protocol, consisting of locating sample, ion beam milling and micro-mechanical bending tests, can be carried out without sample transfer or reattachment. We used our newly devised test platform to evaluate the micromechanical properties and structural features of each separated layer of the beetle horn shell. The Young's modulus of both the exocuticle and endocuticle layers was measured. We carried out a bending test to characterize the layers mechanically. The exocuticle layer bent in a brick-like manner, while the endocuticle layer exhibited a crack blunting effect. STATEMENT OF SIGNIFICANCE: This paper proposed an in-situ manipulation/test method in focused ion beam for characterizing micromechanical properties of beetle horn shell. The challenge in precise and accurate fabrication for the samples with complex geometry was overcome by using nano-manipulators having multi-degree of freedom and a micro-gripper. With the aid of this specially designed test platform, bending tests were carried out on cantilever-shaped samples prepared by focused ion beam milling. Structural differences between exocuticle and endocuticle layers of beetle horn shell were explored and the results provided insight into the structural advantages of each biocomposite structure.
[Mh] Termos MeSH primário: Estruturas Animais/química
Coleópteros/química
Módulo de Elasticidade
Estresse Mecânico
[Mh] Termos MeSH secundário: Animais
[Pt] Tipo de publicação:JOURNAL ARTICLE
[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:170430
[St] Status:MEDLINE


  7 / 59501 MEDLINE  
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[PMID]:28454723
[Au] Autor:Ma Y; Fu S; Lu L; Wang X
[Ad] Endereço:School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China.
[Ti] Título:Role of androgen receptor on cyclic mechanical stretch-regulated proliferation of C2C12 myoblasts and its upstream signals: IGF-1-mediated PI3K/Akt and MAPKs pathways.
[So] Source:Mol Cell Endocrinol;450:83-93, 2017 Jul 15.
[Is] ISSN:1872-8057
[Cp] País de publicação:Ireland
[La] Idioma:eng
[Ab] Resumo:OBJECTS: To detect the effects of androgen receptor (AR) on cyclic mechanical stretch-modulated proliferation of C2C12 myoblasts and its pathways: roles of IGF-1, PI3K and MAPK. METHODS: C2C12 were randomly divided into five groups: un-stretched control, six or 8 h of fifteen percent stretch, and six or 8 h of twenty percent stretch. Cyclic mechanical stretch of C2C12 were completed using a computer-controlled FlexCell Strain Unit. Cell proliferation and IGF-1 concentration in medium were detected by CCK8 and ELISA, respectively. Expressions of AR and IGF-1R, and expressions and activities of PI3K, p38 and ERK1/2 in stretched C2C12 cells were determined by Western blot. RESULTS: â‘ The proliferation of C2C12 cells, IGF-1 concentration in medium, expressions of AR and IGF-1R, and activities of PI3K, p38 and ERK1/2 were increased by 6 h of fifteen percent stretch, while decreased by twenty percent stretch for six or 8 h â‘¡The fifteen percent stretch-increased proliferation of C2C12 cells was reversed by AR inhibitor, Flutamide. â‘¢The increases of AR expression, activities of PI3K, p38 and ERK1/2 resulted from fifteen percent stretch were attenuated by IGF-1 neutralizing antibody, while twenty percent stretch-induced decreases of the above indicators were enhanced by recombinant IGF-1. â‘£Specific inhibitors of p38, ERK1/2 and PI3K all decreased the expression of AR in fifteen percent and twenty percent of stretched C2C12 cells. CONCLUSIONS: Cyclic mechanical stretch modulated the proliferation of C2C12 cells, which may be attributed to the alterations of AR via IGF-1-PI3K/Akt and IGF-1-MAPK (p38, ERK1/2) pathways in C2C12 cells.
[Mh] Termos MeSH primário: Fator de Crescimento Insulin-Like I/metabolismo
Proteínas Quinases Ativadas por Mitógeno/metabolismo
Mioblastos/citologia
Fosfatidilinositol 3-Quinases/metabolismo
Proteínas Proto-Oncogênicas c-akt/metabolismo
Receptores Androgênicos/metabolismo
Estresse Mecânico
[Mh] Termos MeSH secundário: Animais
Anticorpos Neutralizantes/farmacologia
Linhagem Celular
Proliferação Celular/efeitos dos fármacos
MAP Quinases Reguladas por Sinal Extracelular/metabolismo
Camundongos
Mioblastos/efeitos dos fármacos
Mioblastos/enzimologia
Mioblastos/metabolismo
Inibidores de Proteínas Quinases/farmacologia
Receptor IGF Tipo 1/metabolismo
Proteínas Recombinantes/farmacologia
Transdução de Sinais/efeitos dos fármacos
Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Antibodies, Neutralizing); 0 (Protein Kinase Inhibitors); 0 (Receptors, Androgen); 0 (Recombinant Proteins); 67763-96-6 (Insulin-Like Growth Factor I); EC 2.7.1.- (Phosphatidylinositol 3-Kinases); EC 2.7.10.1 (Receptor, IGF Type 1); EC 2.7.11.1 (Proto-Oncogene Proteins c-akt); EC 2.7.11.24 (Extracellular Signal-Regulated MAP Kinases); EC 2.7.11.24 (Mitogen-Activated Protein Kinases); EC 2.7.11.24 (p38 Mitogen-Activated Protein Kinases)
[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:170430
[St] Status:MEDLINE


  8 / 59501 MEDLINE  
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[PMID]:29370213
[Au] Autor:Borg SA; Buckley H; Owen R; Marin AC; Lu Y; Eyles D; Lacroix D; Reilly GC; Skerry TM; Bishop NJ
[Ad] Endereço:Academic Unit of Child Health Department of Oncology & Metabolism, University of Sheffield, Sheffield, United Kingdom.
[Ti] Título:Early life vitamin D depletion alters the postnatal response to skeletal loading in growing and mature bone.
[So] Source:PLoS One;13(1):e0190675, 2018.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:There is increasing evidence of persistent effects of early life vitamin D exposure on later skeletal health; linking low levels in early life to smaller bone size in childhood as well as increased fracture risk later in adulthood, independently of later vitamin D status. A major determinant of bone mass acquisition across all ages is mechanical loading. We tested the hypothesis in an animal model system that early life vitamin D depletion results in abrogation of the response to mechanical loading, with consequent reduction in bone size, mass and strength during both childhood and adulthood. A murine model was created in which pregnant dams were either vitamin D deficient or replete, and their offspring moved to a vitamin D replete diet at weaning. Tibias of the offspring were mechanically loaded and bone structure, extrinsic strength and growth measured both during growth and after skeletal maturity. Offspring of vitamin D deplete mice demonstrated lower bone mass in the non loaded limb and reduced bone mass accrual in response to loading in both the growing skeleton and after skeletal maturity. Early life vitamin D depletion led to reduced bone strength and altered bone biomechanical properties. These findings suggest early life vitamin D status may, in part, determine the propensity to osteoporosis and fracture that blights later life in many individuals.
[Mh] Termos MeSH primário: Desenvolvimento Ósseo
Osso e Ossos/fisiopatologia
Deficiência de Vitamina D/fisiopatologia
[Mh] Termos MeSH secundário: Animais
Densidade Óssea
Feminino
Análise de Elementos Finitos
Seres Humanos
Camundongos
Camundongos Endogâmicos C57BL
Gravidez
Estresse Mecânico
Vitamina D/administração & dosagem
Microtomografia por Raio-X
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
1406-16-2 (Vitamin D)
[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:180126
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0190675


  9 / 59501 MEDLINE  
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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


  10 / 59501 MEDLINE  
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[PMID]:28467360
[Au] Autor:Herzfeld E; Speh L; Strauss C; Scheller C
[Ad] Endereço:Department of Neurosurgery, Martin-Luther University of Halle-Wittenberg, Ernst-Grube-Str. 40, 06120 Halle (Saale), Germany. eva.herzfeld@uk-halle.de.
[Ti] Título:Nimodipine but Not Nifedipine Promotes Expression of Fatty Acid 2-Hydroxylase in a Surgical Stress Model Based on Neuro2a Cells.
[So] Source:Int J Mol Sci;18(5), 2017 May 03.
[Is] ISSN:1422-0067
[Cp] País de publicação:Switzerland
[La] Idioma:eng
[Ab] Resumo:Nimodipine is well characterized for the management of aneurysmal subarachnoid hemorrhage and has been shown to promote a better outcome and less delayed ischemic neurological deficits. Animal and clinical trials show neuroprotective efficacy following nerve injuries. We showed a neuroprotective effect on Neuro2a cells. Subsequent microarray analysis revealed-among others-fatty acid 2-hydroxylase (FA2H) upregulated by nimodipine in vitro, which is a component of myelin synthesis. Differentiated Neuro2a cells were analyzed for nimodipine-mediated survival considering stress treatment in comparison to nifedipine-treatment. Cell survival was determined by measurement of LDH activity in the culture medium. Nimodipine decreased surgery-like stress-induced cell death of differentiated Neuro2a cells. Neuro2a cell culture was analyzed for changes in FA2H expression induced by nimodipine or nifedipine in surgery-like stress conditions. We analyzed expression levels of FA2H mRNA and protein by qPCR using specific primers or a FA2H-specific antibody in nimodipine or nifedipine non- and pre-treated Neuro2a cell culture, respectively. Nimodipine but not nifedipine increases FA2H protein levels and also significantly increases mRNA levels of FA2H in both undifferentiated and differentiated Neuro2a cells. Our findings indicate that higher expression of FA2H induced by nimodipine may cause higher survival of Neuro2a cells stressed with surgery-like stressors.
[Mh] Termos MeSH primário: Bloqueadores dos Canais de Cálcio/farmacologia
Resposta ao Choque Térmico/efeitos dos fármacos
Oxigenases de Função Mista/metabolismo
Fármacos Neuroprotetores/farmacologia
Procedimentos Neurocirúrgicos/efeitos adversos
Nifedipino/farmacologia
Nimodipino/farmacologia
Estresse Oxidativo/efeitos dos fármacos
[Mh] Termos MeSH secundário: Animais
Morte Celular/efeitos dos fármacos
Diferenciação Celular/efeitos dos fármacos
Linhagem Celular
Sobrevivência Celular/efeitos dos fármacos
Expressão Gênica
Camundongos
Oxigenases de Função Mista/genética
Bainha de Mielina/metabolismo
Nimodipino/uso terapêutico
RNA Mensageiro/genética
Estresse Mecânico
Regulação para Cima
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Calcium Channel Blockers); 0 (Neuroprotective Agents); 0 (RNA, Messenger); 57WA9QZ5WH (Nimodipine); EC 1.- (Mixed Function Oxygenases); EC 1.- (fatty acid alpha-hydroxylase); I9ZF7L6G2L (Nifedipine)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180221
[Lr] Data última revisão:
180221
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170504
[St] Status:MEDLINE



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