Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 167
Filtrar
1.
Chem Commun (Camb) ; 2020 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-32067022

RESUMO

A novel nanoarchitecture (MSN-Tb-UbR) was prepared by modifying rhodamine B-labelled Ubs (Ub-Rs) on the surface of mesoporous silica nanoparticles (MSNs) loaded with Tb3+-complexes. The MSN-Tb-UbR exhibits ratiometric sensing ability for DUB (UCH-L1) with good sensitivity and selectivity.

2.
Int Immunopharmacol ; 78: 105953, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31784401

RESUMO

Osteoarthritis(OA) is one of the most common diseases in orthopedics. It is characterized by degeneration of articular cartilage and chronic inflammation. In this study, we aim to elucidate the mechanism of Loureirin A's therapeutic effect in OA progression. In vitro, Loureirin A pretreatment can significantly inhibit production of NO, PGE2, COX-2, TNF-α, iNOS andIL-6 induced by IL-1ß in mouse articular chondrocytes. Moreover, Loureirin A suppressed the expression of matrix metalloproteinase-9(MMP-9), which leads to degradation of the extracellular matrix. The degradation of aggrecan and type II collagen protein in the extracellular matrix (ECM) stimulated by IL-1ß was reversed. For signal pathway research, Loureirin A dramatically inhibited the phosphorylation of AKT and subsequent NF-κB entering into the nucleus caused by IL-1ß in chondrocytes. Besides, a number of related indicators suggested that Loureirin A has a strong antioxidant activity in the treatment of osteoarthritis via increasing content of SOD2 and suppressing MDA and ROS. In addition, in vivo study demonstrated that Loureirin A could ameliorated the progression of OA in mice DMM model In conclusion, all results showed that Loureirin A may be a potential therapeutic candidate for the OA.

3.
Cell Discov ; 5: 40, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31636953

RESUMO

Isotope-labeling-based mass spectrometry (MS) is widely used in quantitative proteomic studies. With this technique, the relative abundance of thousands of proteins can be efficiently profiled in parallel, greatly facilitating the detection of proteins differentially expressed across samples. However, this task remains computationally challenging. Here we present a new approach, termed Model-based Analysis of Proteomic data (MAP), for this task. Unlike many existing methods, MAP does not require technical replicates to model technical and systematic errors, and instead utilizes a novel step-by-step regression analysis to directly assess the significance of observed protein abundance changes. We applied MAP to compare the proteomic profiles of undifferentiated and differentiated mouse embryonic stem cells (mESCs), and found it has superior performance compared with existing tools in detecting proteins differentially expressed during mESC differentiation. A web-based application of MAP is provided for online data processing at http://bioinfo.sibs.ac.cn/shaolab/MAP.

4.
Int J Ophthalmol ; 12(10): 1561-1566, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31637191

RESUMO

AIM: To compare the prediction error between Barrett Toric calculator and the new online AcrySof Toric calculator which incorporated Barrett astigmatism algorithm in Chinese cataract eyes with normal axial length and anterior chamber depth (ACD). METHODS: Prospective case-control study. All the cases had axial length (21-26 mm) with ACD no less than 2.4 mm. Keratometric values were measured by LenSTAR 900. The Barrett Toric calculator was used in group 1. In group 2, SRK-T formula was used to determine the spherical power of the Toric lens, and subsequent calculation of the cylinder type was performed using the new online Alcon Toric calculator. At 1 and 3mo after surgery, a comprehensive subjective optometry was performed. The predicted residual astigmatism calculated by the two calculators was compared with that obtained by postoperative refraction, and the difference was defined as the astigmatism correction error [error of refractive astigmatism (ERA)]. The error magnitude (EM) refers to the algebraic deviation of ERA, and the error vector (EV) indicates the vector deviation of ERA. The influence of the two calculation methods on the correction accuracy of toric IOL was quantitatively analyzed. RESULTS: The |EM| obtained at 1mo after surgery were 0.21±0.12 D, 0.22±0.18 D in group 1 and group 2 respectively, and correspondingly turned to be 0.19±0.13 D, 0.20±0.19 D at 3mo after surgery, with no statistical difference (P=0.633, P=0.877). The vector analysis showed that |EV| values in two groups at 1mo after surgery were 0.29±0.14@105 (D@angle) and 0.35±0.20@113 (D@angle), respectively, whereas |EV| values 3mo after surgery were 0.27±0.16@86 (D@angle) and 0.32±0.23@102 (D@angle), respectively. The differences between the groups were not statistically significant (P=0.119, P=0.261). CONCLUSION: The clinical effect of Barrett Toric calculator has a much more accurate tendency than that of new online AcrySof Toric calculator, but is not evident in cases with normal axial length and normal anterior posterior ratio.

5.
ACS Appl Mater Interfaces ; 11(40): 37247-37255, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31508934

RESUMO

Hexagonal boron nitride has displayed increased potential in heat dissipation applications due to its desirable high thermal conductivity and remarkable thermal stability. However, the large-yield and high-quality preparation of boron nitride nanosheets (BNNSs) has been still an enormous challenge. In present work, we developed a universal exfoliation strategy to synthesize few-layer and defect-free BNNSs, which involved the intercalation of hexafluorosilicates/sodium hydroxide into BN crystals followed by exfoliation through a mild stirring process. The yield and concentration of as-obtained BNNS reached up to 78.5% and 12.78 mg/mL, respectively. More importantly, this method has been proven to exfoliate other layered materials like graphene (G), MoS2, and WS2. These as-obtained BNNSs can be directly used for constructing freestanding papers with high thermal conductivities. Typically, the thermal conductivities of the BNNS-G hybrid paper were up to 63.5 W/mK along the in-plane direction and 7.4 W/mK along the through-plane direction. According to the thermal interface materials performance measures, BNNS-G hybrid paper shows great promising applications for heat transfer in integrated circuit packaging.

6.
ACS Appl Mater Interfaces ; 11(35): 31755-31762, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31393692

RESUMO

Nanoscale metal-organic frameworks (NMOFs) have been proved to be effective quenching platforms for fluorescent detection of DNA via fluorophore-quencher pairs. Zeolitic imidazolate framework-8 (ZIF-8) is one type of the most promising NMOFs because of its excellent biocompatibility and easy preparation. However, ZIF-8 is rarely used as platforms for fluorescence sensing of DNA because of its bad fluorescence quenching property. In this study, lanthanide ions were doped into ZIF-8 to regulate its fluorescence quenching behavior. The La3+ doped ZIF-8 (ZIF-8-La) showed the best quenching efficiency on dye-labeled DNA. The signal-to-background ratio was around 3 times higher than ZIF-8. Furthermore, a core-shell La3+-doped ZIF-8 (CS-ZIF-8-La) was designed to modify more La3+ on the surface of ZIF-8. Compared with ZIF-8-La, the CS-ZIF-8-La exhibited the same fluorescence sensing behavior toward positive-dye-labeled DNA, but showed completely contrary quenching property on the negative-dye-labeled DNA. On the basis of this phenomenon, CS-ZIF-8-La was successfully used as quenching platform for designing a ratiometric sensor for DNA and microRNA.


Assuntos
Aptâmeros de Nucleotídeos/química , DNA/análise , Lantânio/química , Estruturas Metalorgânicas/química , MicroRNAs/análise , Zeolitas/química , Fluorescência , Células HeLa , Humanos
7.
BMC Med Inform Decis Mak ; 19(1): 173, 2019 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-31455389

RESUMO

BACKGROUND: Feelings of depression can be caused by negative life events (NLE) such as the death of a family member, a quarrel with one's spouse, job loss, or strong criticism from an authority figure. The automatic and accurate identification of negative life event language patterns (NLE-LP) can help identify individuals potentially in need of psychiatric services. An NLE-LP combines a person (subject) and a reasonable negative life event (action), e.g. or < boyfriend:break_up>. METHODS: This paper proposes an analogical reasoning framework which combines a word representation approach and a pattern inference method to mine/extract NLE-LPs from psychiatric consultation documents. Word representation approaches such as skip-gram (SG) and continuous bag-of-words (CBOW) are used to generate word embeddings. Pattern inference methods such as cosine similarity (COSINE) and cosine multiplication similarity (COSMUL) are used to infer patterns. RESULTS: Experimental results show our proposed analogical reasoning framework outperforms the traditional methods such as positive pairwise mutual information (PPMI) and hyperspace analog to language (HAL), and can effectively mine highly precise NLE-LPs based on word embeddings. CBOW with COSINE of analogical reasoning is the best word representation and inference engine. In addition, both word embeddings and the inference engine provided by the analogical reasoning framework can further be used to improve the HAL model. CONCLUSIONS: Our proposed framework is a very simple matching function based on these word representation approaches and is applied to significantly improve HAL model mining performance.

8.
J R Soc Interface ; 16(156): 20190258, 2019 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-31362619

RESUMO

Migrating cells constantly experience geometrical confinements in vivo, as exemplified by cancer invasion and embryo development. In this paper, we investigate how intrinsic cellular properties and extrinsic channel confinements jointly regulate the two-dimensional migratory dynamics of collective cells. We find that besides external confinement, active cell motility and cell crowdedness also shape the migration modes of collective cells. Furthermore, the effects of active cell motility, cell crowdedness and confinement size on collective cell migration can be integrated into a unified dimensionless parameter, defined as the cellular motility number (CMN), which mirrors the competition between active motile force and passive elastic restoring force of cells. A low CMN favours laminar-like cell flows, while a high CMN destabilizes cell motions, resulting in a series of mode transitions from a laminar phase to an ordered vortex chain, and further to a mesoscale turbulent phase. These findings not only explain recent experiments but also predict dynamic behaviours of cell collectives, such as the existence of an ordered vortex chain mode and the mode selection under non-straight confinements, which are experimentally testable across different epithelial cell lines.

9.
Int Immunopharmacol ; 75: 105817, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31446161

RESUMO

Artesunate (ART), a derivative of artemisinin, is a medication to treat malaria. Beyond that, the anti-inflammatory and immunoregulatory activities of ART have been identified in autoimmune diseases. However, whether ART functions in psoriasis-like dermatitis induced by imiquimod (IMQ, a TLR7/8 agonist) is currently unkown. There, we found that the cumulative score, epidermal thickening and expression of Ki-67 of ART-treated BALB/c mice were significantly lower than those in the IMQ psoriatic model group. In addition, ART treatment ameliorated mice from systemic inflammation. Mechanistically, ART reduced γδ T cells in draining lymph nodes, which might be benefit the improvement of dermatitis. These findings suggested that ART could be a promising drug of psoriasis in clinic.

10.
Curr Med Chem ; 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31237195

RESUMO

The ocular surface structure and extraocular accessory organs constitute the ocular surface system, which includes the cornea, conjunctiva, eyelids, lacrimal organs, and lacrimal passages. This system is composed of, and stabilized by, the corneal epithelium, conjunctival cells, conjunctival goblet cells, lacrimal acinar cells and Tenon's fibroblasts, all of which maintain the healthy eyeball surface system. Ocular surface diseases are commonly referred to corneal and conjunctival disease and external ocular disease, resulting from damage to the ocular surface structure. A growing body of evidence has indicated that abnormal activation of the KCa3.1 channel and Ca2+/ calmodulin-dependent kinase initiates ocular injury. Signaling pathways downstream of the irregular Ca2+ influx induce cell progression and migration, and impair cell tight junctions, epithelial transport and secretory function. In this overview, we summarize the current knowledge regarding ocular surface disease in terms of physical and pathological alteration of the ocular system. We dissect in-depth the mechanisms underlying disease progression, and we describe the current calcium transport therapeutics and the obstacles that remain to be solved. Finally, we summarize how to integrate the research results into clinical practice in the future.

11.
Development ; 146(13)2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31189663

RESUMO

Epigenetic regulation, including histone-to-protamine exchanges, controls spermiogenesis. However, the underlying mechanisms of this regulation are largely unknown. Here, we report that PHF7, a testis-specific PHD and RING finger domain-containing protein, is essential for histone-to-protamine exchange in mice. PHF7 is specifically expressed during spermiogenesis. PHF7 deletion results in male infertility due to aberrant histone retention and impaired protamine replacement in elongated spermatids. Mechanistically, PHF7 can simultaneously bind histone H2A and H3; its PHD domain, a histone code reader, can specifically bind H3K4me3/me2, and its RING domain, a histone writer, can ubiquitylate H2A. Thus, our study reveals that PHF7 is a novel E3 ligase that can specifically ubiquitylate H2A through binding H3K4me3/me2 prior to histone-to-protamine exchange.

12.
J Org Chem ; 84(13): 8423-8439, 2019 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-31136177

RESUMO

Various functional secondary and tertiary phosphines, or their derivatives, containing stationary chiral phosphorus and flexible chiral axis were prepared, which could be further modified to afford diversely chelating ligands. The flexible axial chirality was fixed by stereogenic phosphorus via a cyclic linkage of chemical bonds or coordination with a metallic ion.

13.
Nat Microbiol ; 4(5): 813-825, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30833724

RESUMO

Human immunodeficiency virus (HIV) actively modulates the protein stability of host cells to optimize viral replication. To systematically examine this modulation in HIV infection, we used isobaric tag-based mass spectrometry to quantify changes in the abundance of over 14,000 proteins during HIV-1 infection of human primary CD4+ T cells. We identified P-selectin glycoprotein ligand 1 (PSGL-1) as an HIV-1 restriction factor downregulated by HIV-1 Vpu, which binds to PSGL-1 and induces its ubiquitination and degradation through the ubiquitin ligase SCFß-TrCP2. PSGL-1 is induced by interferon-γ in activated CD4+ T cells to inhibit HIV-1 reverse transcription and potently block viral infectivity by incorporating in progeny virions. This infectivity block is antagonized by Vpu via PSGL-1 degradation. We further show that PSGL-1 knockdown can significantly abolish the anti-HIV activity of interferon-γ in primary CD4+ T cells. Our study identifies an HIV restriction factor and a key mediator of interferon-γ's anti-HIV activity.


Assuntos
Linfócitos T CD4-Positivos/virologia , Infecções por HIV/metabolismo , HIV-1/fisiologia , Interações Hospedeiro-Patógeno , Glicoproteínas de Membrana/metabolismo , Linfócitos T CD4-Positivos/metabolismo , Infecções por HIV/genética , Infecções por HIV/fisiopatologia , Infecções por HIV/virologia , HIV-1/genética , Proteínas do Vírus da Imunodeficiência Humana/genética , Proteínas do Vírus da Imunodeficiência Humana/metabolismo , Humanos , Interferon gama/genética , Interferon gama/metabolismo , Glicoproteínas de Membrana/genética , Proteólise , Proteômica , Proteínas Ligases SKP Culina F-Box/genética , Proteínas Ligases SKP Culina F-Box/metabolismo , Ubiquitinação , Proteínas Virais Reguladoras e Acessórias/genética , Proteínas Virais Reguladoras e Acessórias/metabolismo
15.
J Am Chem Soc ; 141(7): 3006-3013, 2019 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-30735362

RESUMO

In this Article, we expand upon the catalytic hydrothiolation of 1,3-dienes to afford either allylic or homoallylic sulfides with high regiocontrol. Mechanistic studies support a pathway in which regioselectivity is dictated by the choice of counterion associated with the Rh center. Non-coordinating counterions, such as SbF6-, allow for η4-diene coordination to Rh complexes and result in allylic sulfides. In contrast, coordinating counterions, such as Cl-, favor neutral Rh complexes in which the diene binds η2 to afford homoallylic sulfides. We propose mechanisms that rationalize a fractional dependence on thiol for the 1,2-Markovnikov hydrothiolation while accounting for an inverse dependence on thiol in the 3,4- anti-Markovnikov pathway. Through the hydrothiolation of an essential oil (ß-farnesene), we achieve the first enantioselective synthesis of (-)-agelasidine A.

16.
J Biomech ; 84: 234-242, 2019 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-30661732

RESUMO

Collective cell migration is an essential process in embryo development, wound healing, inflammatory response, and cancer invasion. Although cell motions in two-dimensional (2D) monolayers have been studied previously, three-dimensional (3D) collective cell migration, which constantly occurs during embryogenesis such as the establishment of ducts and acini in vivo, remains elusive. In this paper, we develop a cell-based model incorporating cell mechanics and cell motility to address coherent cell motions in a spherical acinus-like lumen with different cell populations. It is found that the interplays between cell persistence, random fluctuation, and geometrical confinement may engender rich and novel migratory modes. In a 3D spherical lumen, two cells may undergo stripe-like or cross-circular coherent rotations, whereas multiple cells can form dynamic twisting or circulating bands, leaving sparse cells at the center or even a hollow cavity in the cell aggregate. The cell density is found to profoundly influence the collective cell migration modes. Our model can reproduce the fundamental features observed in experiments and highlight the role of mechanics in steering 3D collective cell dynamics during mammary acinar morphogenesis.

17.
Curr Gene Ther ; 19(1): 7-19, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30543166

RESUMO

BACKGROUND: As one of the main blinding ocular diseases, corneal blindness resulted from neovascularization that disrupts the angiogenic privilege of corneal avascularity. Following neovascularization, inflammatory cells are infiltrating into cornea to strengthen corneal injury. How to maintain corneal angiogenic privilege to treat corneal disease has been investigated for decades. METHODOLOGY: Local administration of viral and non-viral-mediated anti-angiogenic factors reduces angiogenic protein expression in situ with limited or free of off-target effects upon gene delivery. Recently, Mesenchymal Stem Cells (MSCs) have been studied to treat corneal diseases. Once MSCs are manipulated to express certain genes of interest, they could achieve superior therapeutic efficacy after transplantation. DISCUSSION: In the text, we first introduce the pathological development of corneal disease in the aspects of neovascularization and inflammation. We summarize how MSCs become an ideal candidate in cell therapy for treating injured cornea, focusing on cell biology, property and features. We provide an updated review of gene-based therapies in animals and preclinical studies in the aspects of controlling target gene expression, safety and efficacy. Gene transfer vectors are potent to induce candidate protein expression. Delivered by vectors, MSCs are equipped with certain characters by expressing a protein of interest, which facilitates better for MSC-mediated therapeutic intervention for the treatment of corneal disease. CONCLUSION: As the core of this review, we discuss how MSCs could be engineered to be vector system to achieve enhanced therapeutic efficiency after injection.

18.
World Neurosurg ; 122: e48-e58, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30236812

RESUMO

BACKGROUND: Cervical sagittal imbalance compromises health-related quality of life and can lead to myriad incapacitating symptoms through compression of the spinal cord. Questions regarding which parameters play primary roles in the progression of cervical sagittal imbalance and which might be compensatory factors remain unanswered. METHODS: This study enrolled 246 asymptomatic volunteers from July 2016 to June 2018. After demographic and radiologic parameters were measured, the data were analyzed using correlation coefficient test and multiple regression analysis. A predictive equation was assessed with variance analysis, residual analysis, collinearity analysis, and a paired t test. RESULTS: Average values are as follows: orbital tilt, 64 ± 6°; orbital slope (OS), 15 ± 6°; C0-C2 lordosis (C0C2), 28 ± 8°; cervical lordosis (CL), 5 ± 11°; C2-C7 sagittal vertical axis (C2C7SVA), 15 ± 8 mm; T1 slope (TS), 17 ± 6°; thoracic inlet angle, 69 ± 8°; thoracic kyphosis, 34 ± 9°; lumbar lordosis, 50 ± 10°; sacral slope, 38 ± 7°; pelvic index, 48 ± 9°; sagittal vertical axis, 10 ± 19 mm. Correlations of C2C7SVA were observed with body mass index (BMI), OS, C0C2, CL, and TS. The validated predictive equation was: C2C7SVA = 0.38 × BMI - 0.73 × OS + 0.73 × C0C2 + 0.15 × CL + 0.18 × TS - 6.53. CONCLUSIONS: BMI, OS, C0C2, CL, and TS were primary influencers in the progression of cervical sagittal imbalance and established a predictive equation of asymptomatic population, which can provide clinical advice and remind surgeons of the primary influencers of reconstructive surgery for better prognoses.


Assuntos
Vértebras Cervicais/diagnóstico por imagem , Curvaturas da Coluna Vertebral/diagnóstico por imagem , Idoso , Índice de Massa Corporal , Progressão da Doença , Feminino , Humanos , Masculino , Dados Preliminares , Análise de Regressão , Curvaturas da Coluna Vertebral/epidemiologia
19.
J Am Chem Soc ; 140(48): 16450-16454, 2018 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-30451496

RESUMO

We report a Pd-catalyzed intermolecular hydrophosphinylation of 1,3-dienes to afford chiral allylic phosphine oxides. Commodity dienes and air stable phosphine oxides couple to generate organophosphorus building blocks with high enantio- and regiocontrol. This method constitutes the first asymmetric hydrophosphinylation of dienes.


Assuntos
Alcadienos/química , Compostos Alílicos/síntese química , Fosfinas/química , Catálise , Técnicas de Química Sintética/métodos , Complexos de Coordenação/química , Paládio/química , Fosfinas/síntese química , Estereoisomerismo
20.
Biophys J ; 115(9): 1826-1835, 2018 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-30297134

RESUMO

Collective cell migration occurs in a diversity of physiological processes such as wound healing, cancer metastasis, and embryonic morphogenesis. In the collective context, cohesive cells may move as a translational solid, swirl as a fluid, or even rotate like a disk, with scales ranging from several to dozens of cells. In this work, an active vertex model is presented to explore the regulatory roles of social interactions of neighboring cells and environmental confinements in collective cell migration in a confluent monolayer. It is found that the competition between two kinds of intercellular social interactions-local alignment and contact inhibition of locomotion-drives the cells to self-organize into various dynamic coherent structures with a spatial correlation scale. The interplay between this intrinsic length scale and the external confinement dictates the migration modes of collective cells confined in a finite space. We also show that the local alignment-contact inhibition of locomotion coordination can induce giant density fluctuations in a confluent cell monolayer without gaps, which triggers the spontaneous breaking of orientational symmetry and leads to phase separation.


Assuntos
Movimento Celular , Animais , Contagem de Células , Cães , Células Madin Darby de Rim Canino , Modelos Biológicos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA