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1.
Sensors (Basel) ; 23(3)2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36772399

RESUMO

Recent developments in robotics have heightened the need for visual SLAM. Dynamic objects are a major problem in visual SLAM which reduces the accuracy of localization due to the wrong epipolar geometry. This study set out to find a new method to address the low accuracy of visual SLAM in outdoor dynamic environments. We propose an adaptive feature point selection system for outdoor dynamic environments. Initially, we utilize YOLOv5s with the attention mechanism to obtain a priori dynamic objects in the scene. Then, feature points are selected using an adaptive feature point selector based on the number of a priori dynamic objects and the percentage of a priori dynamic objects occupied in the frame. Finally, dynamic regions are determined using a geometric method based on Lucas-Kanade optical flow and the RANSAC algorithm. We evaluate the accuracy of our system using the KITTI dataset, comparing it to various dynamic feature point selection strategies and DynaSLAM. Experiments show that our proposed system demonstrates a reduction in both absolute trajectory error and relative trajectory error, with a maximum reduction of 39% and 30%, respectively, compared to other systems.

2.
Exp Cell Res ; 386(2): 111732, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31770531

RESUMO

Acquisition of features of mesenchymal cells represents a key step of metastatic progression of cancer cells and searching for mechanisms underlying the acquisition will help design novel clinical strategies for suppressing the metastatic progression. The Deleted in Liver Cancer-1 (DLC-1) gene is a p122/RhoGAP tumor/metastatic suppressor gene. However, the mechanism underlying DLC-1's inhibition of metastasis still remains largely unknown. In this study, we revealed that the DLC-1-deficient, but not the DLC-1-competent, human non-small cell lung carcinoma cells (NSCLCs) could acquire the TGF-ß1-induced expression of CD105, a common surface marker of mesenchymal stem cells, with consequent increase in CD105-associated cell motility. Interestingly, the induced CD105 expression and cell motility were subjected to the inhibition by the DLC-1-RhoA-Rock1 signaling through inhibiting the serine phosphorylation at a linker region, but not at the C-terminus, of the Smad3 protein and Smad3 protein nuclear translocation down the canonical TGF-ß1 signaling. In addition, the evidence suggested that DLC-1 very likely exerted its inhibitory effects on the TGF-ß1 signaling and the associated CD105 acquisition in both the cytoplasm and the nucleus. Consistent to the in vitro findings, a reverse correlation between CD105 and DLC-1 in protein expression was identified in primary NSCLC tissues and their surrounding non-tumor tissues. In summary, this study revealed a novel anti-metastasis mechanism governed by the DLC-1 tumor/metastasis suppressor, thus helping design new diagnostic and therapeutic approaches for NSCLCs.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/genética , Endoglina/genética , Proteínas Ativadoras de GTPase/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias Pulmonares/genética , Fator de Crescimento Transformador beta1/genética , Proteínas Supressoras de Tumor/genética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Linhagem Celular Tumoral , Movimento Celular , Núcleo Celular/metabolismo , Proliferação de Células , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Citosol/metabolismo , Endoglina/metabolismo , Proteínas Ativadoras de GTPase/metabolismo , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Metástase Linfática , Células-Tronco Mesenquimais/metabolismo , Células-Tronco Mesenquimais/patologia , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Fosforilação , Transporte Proteico , Transdução de Sinais , Proteína Smad3/genética , Proteína Smad3/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Quinases Associadas a rho/genética , Quinases Associadas a rho/metabolismo , Proteína rhoA de Ligação ao GTP/genética , Proteína rhoA de Ligação ao GTP/metabolismo
3.
BMC Cancer ; 20(1): 1064, 2020 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-33148199

RESUMO

BACKGROUND: Immunomodulatory activities of human mesenchymal stromal /stem cells (hMSCs) has been widely recognized as the most critical function of hMSCs for exerting its therapeutic effects. However, the detailed mechanisms responsible for regulating the immunomodulation of hMSCs still remain largely unknown. Previous studies revealed that the Notch1 protein exerted a pro-immunomodulatory function probably through interacting with the protein(s) subjective to proteasome-mediated protein degradation. The DLC-1 protein represents a well characterized tumor suppressor subjective to proteasome-mediated degradation. However, the detailed signaling pathway of Notch1 and the involvement of DLC-1 in regulating the immunomodulation of hMSCs have not been studied before. METHODS: The transfection with cDNA or siRNA into hMSCs assisted by co-culture of hMSCs with peripheral blood mononuclear cells and small molecule inhibitors of signaling proteins, followed by immunoprecipitation, Western blotting, RT-PCR, and flowcytometry, were employed to characterize the Notch1 signaling, to identify DLC-1 as a candidate proteasome-targeted protein, and to characterize DLC-1 signaling pathway and its interaction with the Notch1 signaling, in the regulation of immunomodulation of hMSCs, specifically, the inhibition of pro-inflammatory CD4+-Th1 lymphocytes, and the release of immunomodulatory molecule IDO1. STATISTICAL ANALYSIS: One-way ANOVA was utilized as a statistical tool to analyze the data presented as means ± SEM of at least three separate experiments. RESULTS: The present study revealed that the Notch1-Hey1 axis, but not the Notch1-Hes1 axis, was likely responsible for mediating the pro-immunomodulatory function of the Notch1 signaling. The DLC-1 protein was found subjective to proteasome-mediated protein degradation mediated by the DDB1 and FBXW5 E3 ligases and served as an inhibitor of the immunomodulation of hMSCs through inhibiting Rock1, but not Rock2, downstream the DLC-1 signaling. The Notch1 signaling in the Notch1-Hey1 pathway and the DLC-1 signaling in the DLC-1-Rock1-FBXW5 pathway exhibited a mutual exclusion interaction in the regulation of immunomodulation of hMSCs. CONCLUSIONS: The present study uncovers a novel function of DLC-1 tumor suppressor in regulating the immunomodulation of hMSCs. It also proposes a novel mutual exclusion mechanism between the DLC-1 signaling and the Notch1 signaling that is possibly responsible for fine-tuning the immunomodulation of hMSCs with different clinical implications in hMSCs therapy.


Assuntos
Proteínas F-Box/metabolismo , Proteínas Ativadoras de GTPase/metabolismo , Imunomodulação , Leucócitos Mononucleares/imunologia , Células-Tronco Mesenquimais/imunologia , Receptor Notch1/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Quinases Associadas a rho/metabolismo , Células Cultivadas , Técnicas de Cocultura , Proteínas F-Box/genética , Proteínas Ativadoras de GTPase/genética , Genes Supressores de Tumor , Humanos , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/metabolismo , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Receptor Notch1/genética , Transdução de Sinais , Proteínas Supressoras de Tumor/genética , Quinases Associadas a rho/genética
4.
Electrophoresis ; 37(10): 1367-75, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26829671

RESUMO

Graphene oxide (GO) has been considered as a promising stationary phase for chromatographic separation. However, the very strong adsorption of the analytes on the GO surface lead to the severe peak tailing, which in turn resulting in decreased separation performance. In this work, GO and silica nanoparticles hybrid nanostructures (GO/SiO2 NPs@column) were coated onto the capillary inner wall by passing the mixture of GO and silica sol through the capillary column. The successful of coating of GO/SiO2 NPs onto the capillary wall was confirmed by SEM and electroosmotic flow mobilities test. By partially covering the GO surface with silica nanoparticles, the peak tailing was decreased greatly while the unique high shape selectivity arises from the surface of remained GO was kept. Consequently, compared with the column modified with GO (GO@column), the column modified with GO and silica nanoparticles through layer-by-layer method (GO-SiO2 NPs@column), or the column modified with silica nanoparticles (SiO2 NPs@column), GO/SiO2 NPs@column possessed highest resolutions. The GO/SiO2 NPs@column was applied to separate egg white and both acidic and basic proteins as well as three glycoisoforms of ovalbumin were separated in a single run within 36 min. The intra-day, inter-day, and column-to-column reproducibilities were evaluated by calculating the RSDs of the retention of naphthalene and biphenyl in open-tubular capillary electrochromatography. The RSD values were found to be less than 7.1%.


Assuntos
Eletrocromatografia Capilar/métodos , Nanocompostos/química , Proteínas/isolamento & purificação , Clara de Ovo/química , Grafite/química , Nanopartículas/química , Óxidos/química , Tamanho da Partícula , Dióxido de Silício/química , Propriedades de Superfície
5.
Electrophoresis ; 37(15-16): 2175-80, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27174427

RESUMO

In this work, open-tubular capillary column coated with zeolite imidazolate framework-8 (ZIF-8) nanocrystals was prepared by a layer-by-layer method. The coating was formed by growing ZIF-8 nanocrystals on either bare fused silica capillary wall or the capillary column premodified with amino groups. The shape and the thickness of the coating formed by using these two methods were almost the same. However, the coverage of the ZIF-8 crystals on the bare fused silica capillary wall was higher than that on the capillary column premodified with amino groups. The ZIF-8 coated capillary column was evaluated for open-tubular capillary electrochromatography. The effect of pH value, buffer concentration, and applied voltage on the separation of phenols was investigated. Good separation of nine phenolic isomers was achieved because of the strong interaction between unsaturated Zn sites and phenols. The column performance for o-nitrophenol was as high as 208 860 plates m(-1) . The run-to-run, day-to-day, and column-to-column reproducibility of retention time and resolution for p-nitrophenol and o-nitrophenol were very good with RSDs of less than 6.5%.


Assuntos
Eletrocromatografia Capilar/instrumentação , Nanopartículas/química , Nitrofenóis/isolamento & purificação , Zeolitas/química , Eletrocromatografia Capilar/métodos , Imidazóis/química
6.
J Pharm Biomed Anal ; 240: 115886, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38184916

RESUMO

The generation of an immune response in neoantigen-based products relies on antigen presentation, which is closely analyzed by bioassays for T-cell functions such as tetramer or cytokine release. Mass spectrometry (MS) has the potential to directly assess the antigen-presenting capability of antigen-presenting cells (APCs), offering advantages such as speed, multi-target analysis, robustness, and ease of transferability. However, it has not been used for quality control of these products due to challenges in sensitivity, including the number of cells and peptide diversity. In this study, we describe the development and validation of an improved targeted LC-MS/MS method with high sensitivity for characterizing antigen presentation, which could be applied in the quality control of neoantigen-based products. The parameters for the extraction were carefully optimized by different short peptides. Highly sensitive targeted triple quadrupole mass spectrometry combined with ultra-high performance liquid chromatography (UHPLC) was employed using a selective ion monitoring mode (Multiple Reaction Monitoring, MRM). Besides, we successfully implemented robust quality control peptides to ensure the reliability and consistency of this method, which proved invaluable for different APCs. With reference to the guidelines from ICH Q2 (R2), M10, as well as considering the specific attributes of the product itself, we validated the method for selectivity, specificity, sensitivity, limit of detection (LOD), recovery rate, matrix effect, repeatability, and application in dendritic cells (DCs) associated with neoantigen-based products. The validation process yields satisfactory results. Combining this approach with T cell assays will comprehensively assess cell product quality attributes from physicochemical and biological perspectives.


Assuntos
Apresentação de Antígeno , Espectrometria de Massas em Tandem , Espectrometria de Massas em Tandem/métodos , Cromatografia Líquida/métodos , Reprodutibilidade dos Testes , Espectrometria de Massa com Cromatografia Líquida , Cromatografia Líquida de Alta Pressão/métodos , Peptídeos
7.
Exp Anim ; 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38987201

RESUMO

Experimental autoimmune encephalomyelitis (EAE) serves as a model for studying multiple sclerosis, with immunization strategies utilizing MOG35-55 peptide, emulsified in adjuvant enriched with mycobacterium tuberculosis (Mtb). This study examined the effects of Bacillus Calmette-Guérin (BCG) as an adjuvant, alongside the impact of MOG35-55 peptide doses and their residual counter ions on EAE development. We found that BCG can be effectively used to induce EAE with similar incidence and severity as heat-killed H37Ra, contingent upon the appropriate MOG35-55 peptide dose. Different immunization doses of MOG35-55 peptide significantly affect EAE development, with higher doses leading to a paradoxical reduction in disease activity, probably due to peripheral tolerance mechanisms. Furthermore, doses of MOG35-55 peptides with acetate showed a more pronounced effect on disease development compared to those containing trifluoroacetic acid (TFA), suggesting the potential influence of residual counter ions on EAE activity. We highlighted the feasibility of applying BCG to the establishment of EAE for the first time. Our findings emphasized the importance of MOG peptide dosage and composition in modulating EAE development, offering insights into the mechanisms of autoimmunity and tolerance. This could have implications for autoimmune disease research and the design of therapeutic strategies.

8.
Zhonghua Yi Xue Za Zhi ; 93(17): 1335-40, 2013 May 07.
Artigo em Zh | MEDLINE | ID: mdl-24029485

RESUMO

OBJECTIVE: To explore whether a tissue-engineered construct composed of autogenous endothelial cells, osteoblasts and a new bioresorbable nano-hydroxyapatite/recombinant human-like collagen/polylactic acid (nHA/RHLC/PLA) would enhance bone regeneration and repair femoral head defects in canine models. METHODS: The bone marrow stem cells (BMSCs) were isolated from bone marrow of canine ilium and cultured in Dulbecco's modified eagle medium:nutrient mixture F-12 culture media for 1 week and the second-generation BMSCs were further induced by osteogenic medium (1×10(-8) mol/L dexamethasone, 10 mmol/L B-sodium glycerophosphate and 50 µg/ml vitamin C) and by endothelial cell grow medium (vascular endothelial growth factor and basic fibroblast growth factor) for 14 days in vitro. Thus BMSCs were induced into ECs and OBs. After the second passage, cells were digested and collected.And cell density was adjusted to 1.0×10(6)/ml.The cells and nHA/RHLC/PLA scaffold were co-cultured for 2-4 hours then nHA/RHLC/PLA scaffold composites prepared. Cavity defects of 8 mm in diameter and 10 mm in height were made in femoral heads.The nHA/RHLC/PLA scaffold composited with ECs and osteoblasts (OBs) (group A) and composited with OBs (group B) were inserted into different defects while cell-free nHA/RHLC/PLA scaffold served as controls (group C). New bone formation and defect repair were evaluated at 3 and 6 months by radiographic examination, histology and bone histomorphometry. RESULTS: New bone formation was evident as early as 3 months in groups A, B and C.At 6 months, abundant bone tissue within defects was observed in group A. The control animals with cell-free scaffold showed less bone formation at both timepoints.The scaffold of nHA/RHLC/PLA was degraded and absorbed gradually with the formation of new bone tissues.Histology and bone histomorphometry further revealed significantly increased trabecular bones in group A compared with groups B and C at 6 months postimplantation (P < 0.01). CONCLUSION: More abundant new bone tissue may be found in the bone defect areas implanted with osteoblast-endotheliocyte composite than osteoblasts composite and scaffold materials only.ECs and osteoblasts derived from BMSC are ideal seed cells for repairing femoral head defects.


Assuntos
Regeneração Óssea , Necrose da Cabeça do Fêmur/cirurgia , Alicerces Teciduais , Animais , Materiais Biocompatíveis , Células Cultivadas , Técnicas de Cocultura , Colágeno , Cães , Durapatita , Células Endoteliais/citologia , Osteoblastos/citologia , Engenharia Tecidual , Cicatrização
9.
Eur J Clin Invest ; 42(7): 751-9, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22324744

RESUMO

BACKGROUND: Colorectal cancer is one of the most rapidly increasing cancers in the world, and accumulation of alterations in oncogenes, tumour suppressor genes and mismatch repair (MMR) genes contributes to colorectal tumorigenesis. Thus, we investigated the alterations of 14 microsatellite loci adjacent to MMR genes, p53, adenomatous polyposis coli (APC) and K-ras in 52 Chinese patients with colorectal cancer. MATERIALS AND METHODS: We performed fluorescent polymerase chain reaction and capillary electrophoresis to analyse microsatellite instability (MSI) and loss of heterozygosity (LOH) in microsatellite loci, which included a panel of nine dinucleotide repeats and the Bethesda consensus panel. Additionally, we screened for mutations in exons 4-9 of p53 and the mutation cluster region (MCR) in APC by DHPLC. Codons 12, 13 and 61 in K-ras were analysed using direct sequencing. All variations were confirmed using clone sequencing. RESULTS: The alteration frequency of microsatellite DNA was 55·8% (29/52). Among the microsatellites, five loci exhibited MSI and another nine loci exhibited LOH. The mutation rates of p53, APC and K-ras were 42·3%, 38·5% and 36·5%, respectively. All patients (n = 7) with liver metastasis had a mutation in p53, APC or K-ras. APC mutation was correlated with clinical stage and the presence of lymph node metastasis (P = 0·001 and P = 0·006, respectively). CONCLUSIONS> A total of 80·8% of Chinese patients with colorectal cancer show variations in microsatellite DNA, p53, APC or K-ras. It appears that these microsatellite DNA alterations could be a new biomarker for colorectal cancer.


Assuntos
Proteína da Polipose Adenomatosa do Colo/genética , Neoplasias Colorretais/genética , DNA de Neoplasias/genética , Repetições de Microssatélites/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteína Supressora de Tumor p53/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Povo Asiático/genética , Neoplasias Colorretais/patologia , Eletroforese Capilar , Feminino , Fluorescência , Humanos , Perda de Heterozigosidade , Masculino , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase
10.
Molecules ; 17(5): 5339-45, 2012 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-22565483

RESUMO

Acridinediones were synthesized by the one-pot Hantzsch condensation of an aromatic aldehyde, 5,5-dimethyl-1,3-cyclohexanedione, and aniline/4-methylaniline in refluxing water. This method has then been extended to the four-component reaction of an aromatic aldehyde, 5,5-dimethyl-1,3-cyclohexanedione, ethyl acetoacetate and ammonium acetate for the synthesis of polyhydroquinoline derivatives. This is an environmentally friendly and efficient procedure providing  good to excellent yields.


Assuntos
Acridinas/síntese química , Aldeídos/química , Compostos de Anilina/química , Cicloexanonas/química , Quinolinas/síntese química , Água/química , Acetatos/química , Acetoacetatos/química , Catálise , Espectroscopia de Ressonância Magnética , Estrutura Molecular
11.
J Colloid Interface Sci ; 614: 12-23, 2022 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-35078082

RESUMO

The conversion of N2 to NH3 is one of the most promising processes in maintaining natural life and chemical production. Photocatalytic nitrogen reduction reaction (NRR) has the advantage of clean and sustainable, which is considered to be an ideal synthesis technology. In this work, we report the successful synthesis of Bi12O17Br2 ultrathin nanosheets through simple alkali treatment and solvothermal method. The Bi12O17Br2 ultrathin nanosheets can improve the separation of carriers and the transfer of photogenerated electrons to N2 molecules, thus improving the photocatalytic efficiency. Of note, the higher Bi/Br atomic ratio in Bi12O17Br2 is beneficial to broaden the light absorption edge, and the high concentration of O atoms is easy to produce oxygen vacancies on the surface during the synthesis process of Bi12O17Br2. The abundant oxygen vacancies and high specific surface area enable N2 molecules and water to have powerful chemical adsorption and activation. In addition, the photocatalytic reduction of N2 to NH3 in pure water shows excellent and stable performance, and the average generation rate of NH3 reaches up to 620.5 µmol·L-1·h-1. This study discovers that rich oxygen vacancies and ultrathin morphology may have a significant part in the process of the photocatalytic nitrogen reduction reaction.


Assuntos
Luz , Oxigênio , Catálise , Nitrogênio , Oxigênio/química , Água
12.
J Tissue Eng Regen Med ; 16(10): 934-944, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35929499

RESUMO

Efficient and large-scale expansion of mesenchymal stem/stromal cells (MSCs) has always been a formidable challenge to researchers in cell-based therapies and regenerative medicine. To reconcile major drawbacks of 2D planar culturing system, we innovatively developed an automated closed industrial scale cell production (ACISCP) platform based on GMP-grade microcarrier for culture of umbilical cord-mesenchymal stem/stromal cells (UCMSCs), in accordance with the criteria of stem cell bank. ACISCP system is a fully closed system, which employs different models of vivaSPIN bioreactors (CytoNiche Biotech, China) for scale-up cell culture and vivaPREP (CytoNiche Biotech, China) for automated cell harvesting and cell dosage preparation. To realize industrial scale expansion of UCMSCs, a three-stage expansion was conducted with 1 L, 5 and 15 L vivaSPIN bioreactors. Using 3D TableTrix® and ACISCP system, we inoculated 1.5 × 107 of UCMSCs into 1 L vivaSPIN bioreactor and finally scaled to two 15 L bioreactor. A final yield of 2.09 × 1010 cells with an overall expansion factor of 1975 within 13 days. The cells were harvested, concentrated, washed and prepared automatically with vivaPREP. The entire process was realized with ACISCP platform and was totally enclosed. Critical quality attributes (CQA) assessments and release tests of MSCs, including sterility, safety, purity, viability, identity, stability and potency were performed accordingly. The quality of cells harvested from 3D culture on the ACISCP and conventional 2D planar culture counterpart has no significant difference. This study provides a bioprocess engineering platform, harnessing GMP-grade 3D TableTrix® microcarriers and ACISCP to achieve industrial-scale manufacturing of clinical-grade hMSCs.


Assuntos
Células-Tronco Mesenquimais , Reatores Biológicos , Técnicas de Cultura de Células , Diferenciação Celular , Proliferação de Células , Terapia Baseada em Transplante de Células e Tecidos , Cordão Umbilical
13.
Cell Prolif ; 55(4): e13182, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35083805

RESUMO

'Requirements for Human-Induced Pluripotent Stem Cells' is the first set of guidelines on human-induced pluripotent stem cells in China, jointly drafted and agreed upon by experts from the Chinese Society for Stem Cell Research. This standard specifies the technical requirements, test methods, and instructions for use, labeling, packaging, storage, transportation, and waste handling for human-induced pluripotent stem cells, which apply to the production and quality control of human-induced pluripotent stem cells. It was released by the Chinese Society for Cell Biology on 9 January 2021 and came into effect on 9 April 2021. We hope that the publication of these guidelines will promote institutional establishment, acceptance, and execution of proper protocols and accelerate the international standardization of human-induced pluripotent stem cells for applications.


Assuntos
Células-Tronco Pluripotentes Induzidas , Diferenciação Celular , China , Humanos
14.
Teach Learn Med ; 23(3): 231-7, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21745057

RESUMO

BACKGROUND: Student mistreatment in medical school is a persistent problem with both known and unexplored consequences [corrected]. PURPOSE: The purpose of this study was to determine whether a perception of having been mistreated in medical school had an association with planning a full-time career in academic medicine. METHOD: Using Association of American Medical Colleges' 2000-2004 Medical School Graduation Questionnaire data, we evaluated the relationship between students' mistreatment experience and their career choice, academic versus nonacademic setting. Meta-analysis and regression were used to evaluate this relationship. RESULTS: At medical schools where relatively high percentages of graduating seniors were planning academic careers, students reporting mistreatment experiences were less likely at graduation to be planning careers in academic medicine. CONCLUSION: A perception of having been mistreated in medical school is related to students' career choices, a finding that may be useful to medical school administrators/faculty and students as mistreatment is addressed in program planning, counseling, and faculty recruitment.


Assuntos
Agressão/psicologia , Escolha da Profissão , Relações Interprofissionais , Faculdades de Medicina , Estudantes de Medicina/psicologia , Adulto , Docentes de Medicina , Feminino , Humanos , Masculino , Análise de Regressão , Inquéritos e Questionários , Adulto Jovem
15.
Stem Cell Res Ther ; 12(1): 53, 2021 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-33422149

RESUMO

BACKGROUND: Mesenchymal stromal cell (MSC)-based therapies are being actively investigated in various inflammatory disorders. However, functional variability among MSCs cultured in vitro will lead to distinct therapeutic efficacies. Until now, the mechanisms behind immunomodulatory functional variability in MSCs are still unclear. METHODS: We systemically investigated transcriptomic variations among MSC samples derived from multiple tissues to reveal their effects on immunomodulatory functions of MSCs. We then analyzed transcriptomic changes of MSCs licensed with INFγ to identify potential molecular mechanisms that result in distinct MSC samples with different immunomodulatory potency. RESULTS: MSCs were clustered into distinct groups showing different functional enrichment according to transcriptomic patterns. Differential expression analysis indicated that different groups of MSCs deploy common regulation networks in response to inflammatory stimulation, while expression variation of genes in the networks could lead to different immunosuppressive capability. These different responsive genes also showed high expression variability among unlicensed MSC samples. Finally, a gene panel was derived from these different responsive genes and was able to regroup unlicensed MSCs with different immunosuppressive potencies. CONCLUSION: This study revealed genes with expression variation that contribute to immunomodulatory functional variability of MSCs and provided us a strategy to identify candidate markers for functional variability assessment of MSCs.


Assuntos
Células-Tronco Mesenquimais , Diferenciação Celular , Células Cultivadas , Humanos , Imunomodulação , Transdução de Sinais
16.
Nat Prod Res ; 35(14): 2360-2364, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31621417

RESUMO

A novel structure of sinomenine isoxazole derivatives is synthesised from sinomenine hydrochloride and aromatic aldehydes and requires six steps. 19 target compounds have been obtained in good yields. The sinomenine hydrochloride transforms to 4-alkynyl sinomenine, which is a key intermediate product to synthesise the target sinomenine isoxazole compounds, after a neutralisation reaction with ammonia and substitution reaction with 3-chloropropyne. Another key intermediate product is 1,3-dipole, which can be obtained from aromatic aldehyde. After treatment with hydroxylamine hydrochloride and then sodium carbonate solution, aromatic aldehyde is converted to aldehyde oxime, which reacts with N-chlorosuccinimide (NCS) to afford aryl hydroximino chloride. 1,3-Dipole is eventually formed in situ while triethylamine (TEA) in DMF is added dropwise. Then 4-alkynyl sinomenine is added to provide the sinomenine isoxazole derivative via 1,3-dipolar cycloaddition reaction as the key step. All the target compounds are characterised by melting point, 1H NMR, 13C NMR, HRMS and FT-IR spectroscopy.


Assuntos
Reação de Cicloadição , Isoxazóis/síntese química , Morfinanos/síntese química , Aldeídos/química , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Morfinanos/química , Espectroscopia de Prótons por Ressonância Magnética , Espectroscopia de Infravermelho com Transformada de Fourier
17.
Biochim Biophys Acta ; 1794(10): 1387-97, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19450710

RESUMO

Transforming growth factor-beta (TGF-beta) can induce G2/M phase-dependent apoptosis and G1/S phase-dependent epithelial-mesenchymal transition (EMT) in hepatocytes, but the underlying mechanism remains poorly understood. In this study, we investigated alterations in the global proteome using two dimensional gel electrophoresis of AML-12 murine hepatocyte cells after treatment with TGF-beta at several time points after synchronization in the G2/M or G1/S phase. Upon TGF-beta treatment, the expression levels of 44 proteins were found to be significantly changed in cells synchronized in the G2/M phase. These proteins were identified by MALDI-TOF/TOF and classified into seven categories according to function. In addition, TGF-beta induced downregulation of glutamine synthetase in cells in G2/M but not G1/S phase, and this was further confirmed by immunoblotting. Moreover, exogenous glutamine completely blocked TGF-beta-induced apoptosis in G2/M and non-synchronized cells, whereas it had no effect on EMT, suggesting that the downregulation of glutamine synthetase is involved in G2/M phase-dependent apoptosis. These results provide new insight into the mechanism of the multifunctional effects of TGF-beta and how apoptosis and EMT are regulated in the same type of cells.


Assuntos
Apoptose/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Proteoma/efeitos dos fármacos , Fator de Crescimento Transformador beta/farmacologia , Animais , Apoptose/fisiologia , Ciclo Celular/fisiologia , Linhagem Celular , DNA/metabolismo , Regulação para Baixo/efeitos dos fármacos , Eletroforese em Gel Bidimensional , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Glutamato-Amônia Ligase/metabolismo , Hepatócitos/citologia , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Potencial da Membrana Mitocondrial , Mesoderma/citologia , Mesoderma/efeitos dos fármacos , Mesoderma/metabolismo , Camundongos , Proteoma/isolamento & purificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrometria de Massas em Tandem
18.
Biol Cell ; 102(1): 1-12, 2009 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-19566485

RESUMO

BACKGROUND INFORMATION: STAT3 (signal transducer and activator of transcription 3) is an important transcription factor involved in many biological events, including apoptosis, tumorigenesis, angiogenesis and epithelial-to-mesenchymal transition. However, no direct evidence for a role of STAT3 in 3T3-L1 adipocyte differentiation has been reported. RESULTS: In the present study, we found that rapid activation of STAT3, lasting for more than 48 h, was elicited upon induction of adipogenesis. Both the STAT3-selective inhibitor stattic and the JAK2 (Janus kinase 2)/STAT3-selective inhibitors AG490 and Gö6976 inhibited STAT3 activation, leading to the suppression of adipocyte differentiation. Adipocyte differentiation was also suppressed by STAT3 siRNA (small interfering RNA) or dominant-negative STAT3. Interestingly, the PPARgamma (peroxisome-proliferator-activated receptor gamma) agonist TAZ (troglitazone) abolished the STAT3-inhibitor- and RNAi (RNA interference)-mediated suppression of adipogenesis. However, TAZ treatment had no effect on the stattic- and AG490-mediated down-regulation of STAT3 activation, suggesting that STAT3 regulates adipocyte differentiation through signalling that occurs upstream of PPARgamma. CONCLUSION: These data indicate that STAT3 functions as a critical factor for adipogenesis via a mechanism involving the PPARgamma activation pathway.


Assuntos
Adipócitos/citologia , Diferenciação Celular , PPAR gama/metabolismo , Fator de Transcrição STAT3/metabolismo , Células 3T3 , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Animais , Carbazóis/farmacologia , Células Cultivadas , Cromanos/farmacologia , Óxidos S-Cíclicos/farmacologia , Inibidores Enzimáticos/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Camundongos , Interferência de RNA , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fator de Transcrição STAT3/antagonistas & inibidores , Tiazolidinedionas/farmacologia , Troglitazona , Tirfostinas/farmacologia
19.
Acta Biochim Biophys Sin (Shanghai) ; 41(10): 839-45, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19779649

RESUMO

Cortactin is an F-actin binding protein, regulating cell movement and adhesive junction assembly. However, the function of cortactin in epithelial-mesenchymal transition (EMT) remains elusive. Here we found that during transforming growth factor-beta1 (TGF-beta1)- induced EMT in AML-12 murine hepatocytes, cortactin underwent tyrosine dephosphorylation. Inhibition of the dephosphorylation of cortactin by sodium vanadate blocked TGF-beta1-induced EMT. Knockdown of cortactin by RNAi led to decrease of intercellular junction proteins E-cadherin and Zonula occludens-1 and induced expression of mesenchymal protein fibronectin. Additionally, knockdown of cortactin further promoted TGF-beta1-induced EMT in AML-12 cells, as determined by EMT markers and cell morphological changes. Moreover, migration assay showed that cortactin knockdown promoted the migration of AML-12 cells, and also enhanced TGF-beta1-induced migration. Our study showed the involvement of cortactin in the TGFbeta1- induced EMT.


Assuntos
Diferenciação Celular/fisiologia , Transdiferenciação Celular/fisiologia , Cortactina/fisiologia , Rim/citologia , Fator de Crescimento Transformador beta1/fisiologia , Células Epiteliais/fisiologia , Histona Acetiltransferases/fisiologia , Humanos , Mesoderma/fisiologia , Proteínas do Tecido Nervoso/fisiologia , Células Tumorais Cultivadas
20.
J Chromatogr A ; 1540: 31-37, 2018 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-29426717

RESUMO

Monodispersed core-shell silica spheres with fibrous shell structure and tunable pore size were prepared by using a one-pot oil-water biphase method. The pore size could be tuned from 7 nm to 37 nm by using organic solvents with different polarities as oil phase. The spheres synthesized by using benzene as organic solvent had the maximum pore size of 37 nm and possessed a surface area of 61 m2 g-1. The obtained wide pore core-shell silica spheres were applied for rapidly separating small molecules, peptides, small proteins, and large proteins with molecular weight up to 200 kDa. Since the pore size of the core-shell silica spheres was sufficiently large for the free access of all the solutes, sharp and symmetric peaks were obtained. The separation performance was as high as 264,531 plates m-1 for fluorene. The great efficient separation demonstrates that the wide pore core-shell silica spheres have a great potential for rapid analysis of both small and large solutes with high performance liquid chromatography.


Assuntos
Cromatografia Líquida de Alta Pressão/instrumentação , Dióxido de Silício/química , Tamanho da Partícula , Peptídeos/isolamento & purificação , Porosidade , Proteínas/isolamento & purificação
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