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1.
Langmuir ; 40(15): 8115-8125, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38563662

RESUMO

Core-shell composite abrasive particles are a topic of great interest in surface finishing. It is important to explore the preparation technology and performance parameters associated with them. In this paper, a core-shell composite abrasive particle made of polystyrene and cerium oxide (PS&CeO2, CSPC), which is rigid on the outside and flexible on the inside, is proposed. The microstructure, physical phase characteristics, and mechanical properties of the inner core and composite abrasive particles are investigated. PS microspheres and CSPC composite abrasive particles with different structural features were prepared through a series of experiments, morphological observations, and physical and chemical characterization experiments. Their microstructures and physical phase properties were investigated. The indentation load curves of the PS microspheres and CSPC composite abrasive samples were measured by using an atomic force microscope. The analysis focused on the effects of various dimensional and structural parameters on the modulus of elasticity of both PS microspheres and CSPC composite abrasive particles. The analysis shows that the experimentally prepared PS microspheres have good dispersion, a smooth surface, and a uniform particle size distribution. The prepared CSPC composite abrasive particles are regular spheres with rough, rice-like surfaces, low modulus of elasticity, and overall nonrigid and soft elastic properties. The results of this paper can provide a guide for the preparation technology, performance regulation, and application of polymer microspheres and core-shell composite abrasive particles in CMP.

2.
Inorg Chem ; 63(38): 17955-17966, 2024 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-39258813

RESUMO

Insight into the modulation effect of oxygen reduction reaction (ORR) active centers is of profound significance but remains a great challenge. Here, we designed Co, Fe dual-metal single-atom sites (CoFe-DSAs/NC) uniformly anchored on nitrogen-doped multiwalled carbon nanotubes for boosting ORR performance through regulating the 4d electronic orbitals of the Co-N4 active site. Mechanism studies revealed that for the first time the neighboring Fe-N4 atomic sites were able to regulate the d-band center of Co-N4 single-atom active centers while maintaining the balance of adsorption-desorption affinity for O2 and oxygen-containing species on Co-N4, thereby resulting in a superior ORR performance with a positive half-wave potential (0.90 V vs RHE). The assembled zinc-air battery based on CoFe-DSAs/NC exhibited an increased open-circuit voltage (1.48 V) and an elevated specific capacity (782.33 mAh·g-1). The work provides a new clue for reasonably designing high-performance ORR catalysts through adjusting the d-band center of active sites.

3.
Mikrochim Acta ; 190(12): 469, 2023 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-37971627

RESUMO

A novel, simple, and rapid method is demonstrated for measuring the pore size and pore size distribution of filtration membranes (FMs) used in aqueous applications with fluorescence probes. Because the selected fluorescent probes are mixable and have strong signals, combined with the operation of dead-end filtration, this method only requires small amounts of reagents; additionally, it is time-efficient by avoiding multiple rounds of filtration. This method detects the size of a FM pore throat (i.e., the narrowest position of a pore tunnel), which is more consistent with the actual filtration situation. The conditions, such as probe concentration, temperature, transmembrane pressure difference, and types of surfactants, have been optimized. The experimental results show that the fluorescence probe method has good accuracy and reproducibility for measuring the pore size and pore size distribution of both organic and inorganic FMs. The method is particularly suitable for rapid testing of the filtration performance (nominal pore size≥0.02 µm) of purchased or synthetic membranes in the laboratory.

4.
BMC Cancer ; 21(1): 938, 2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34416861

RESUMO

BACKGROUND: Lung adenocarcinoma (LUAD) is a major subtype of lung cancer and closely associated with poor prognosis. N6-methyladenosine (m6A), one of the most predominant modifications in mRNAs, is found to participate in tumorigenesis. However, the potential function of m6A RNA methylation in the tumor immune microenvironment is still murky. METHODS: The gene expression profile cohort and its corresponding clinical data of LUAD patients were downloaded from TCGA database and GEO database. Based on the expression of 21 m6A regulators, we identified two distinct subgroups by consensus clustering. The single-sample gene-set enrichment analysis (ssGSEA) algorithm was conducted to quantify the relative abundance of the fraction of 28 immune cell types. The prognostic model was constructed by Lasso Cox regression. Survival analysis and receiver operating characteristic (ROC) curves were used to evaluate the prognostic model. RESULT: Consensus classification separated the patients into two clusters (clusters 1 and 2). Those patients in cluster 1 showed a better prognosis and were related to higher immune scores and more immune cell infiltration. Subsequently, 457 differentially expressed genes (DEGs) between the two clusters were identified, and then a seven-gene prognostic model was constricted. The survival analysis showed poor prognosis in patients with high-risk score. The ROC curve confirmed the predictive accuracy of this prognostic risk signature. Besides, further analysis indicated that there were significant differences between the high-risk and low-risk groups in stages, status, clustering subtypes, and immunoscore. Low-risk group was related to higher immune score, more immune cell infiltration, and lower clinical stages. Moreover, multivariate analysis revealed that this prognostic model might be a powerful prognostic predictor for LUAD. Ultimately, the efficacy of this prognostic model was successfully validated in several external cohorts (GSE30219, GSE50081 and GSE72094). CONCLUSION: Our study provides a robust signature for predicting patients' prognosis, which might be helpful for therapeutic strategies discovery of LUAD.


Assuntos
Adenocarcinoma de Pulmão/patologia , Adenosina/análogos & derivados , Biomarcadores Tumorais/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias Pulmonares/patologia , Processamento Pós-Transcricional do RNA , Microambiente Tumoral/imunologia , Adenocarcinoma de Pulmão/classificação , Adenocarcinoma de Pulmão/genética , Adenocarcinoma de Pulmão/imunologia , Adenosina/química , Epigênese Genética , Humanos , Neoplasias Pulmonares/classificação , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/imunologia , Metilação , Prognóstico , Taxa de Sobrevida , Transcriptoma
5.
Sensors (Basel) ; 21(16)2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34450980

RESUMO

Copper (II) ions have been shown to greatly improve the chemical stability and peroxidase-like activity of gold nanoclusters (AuNCs). Since the affinity between Cu2+ and pyrophosphate (PPi) is higher than that between Cu2+ and AuNCs, the catalytic activity of AuNCs-Cu2+ decreases with the introduction of PPi. Based on this principle, a new colorimetric detection method of PPi with high sensitivity and selectivity was developed by using AuNCs-Cu2+ as a probe. Under optimized conditions, the detection limit of PPi was 0.49 nM with a linear range of 0.51 to 30,000 nM. The sensitivity of the method was three orders of magnitude higher than that of a fluorescence method using AuNCs-Cu2+ as the probe. Finally, the AuNCs-Cu2+ system was successfully applied to directly determine the concentration of PPi in human urine samples.


Assuntos
Ouro , Nanopartículas Metálicas , Colorimetria , Cobre , Difosfatos , Corantes Fluorescentes , Humanos , Limite de Detecção , Peroxidase , Peroxidases , Espectrometria de Fluorescência
6.
Phys Chem Chem Phys ; 22(30): 17229-17235, 2020 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-32685948

RESUMO

Compared with the conventional magnetic means (such as ferromagnetic contacts), controlling a spin current by electrical methods could largely reduce the energy consumption and dimensions of nano-devices, which has become a focus of research in spintronics. Inspired by recent progress in the synthesis of an iron-based metal-organic nanostructure, we investigate the spin-dependent electronic transport of the molecule of Fe3-terpyridine-phenyl-phenyl-terpyridine-Fe3 (Fe3-TPPT-Fe3) through first-principles calculations, and propose a three-terminal device without ferromagnetics. By applying a gate voltage, not only the spin polarization can be switched between 100% and -100% to achieve a dual-spin filter, but also its fine regulation can be realized, where the transmission with any ratio of spin-up to spin-down electron numbers is achievable. Analysis shows that the particular transmission spectra are the key mechanism, where two peaks reside discretely on both sides of the Fermi level with opposite spins. Such a feature is found to be robust to the number of Fe atoms and TPPT chain length, suggesting that it is an intrinsic feature of such systems and very conducive to practical applications. The electrical control (such as an electric field) of spin polarization is realized at the single-molecule level, showing great application potential.

7.
Mikrochim Acta ; 186(5): 271, 2019 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-30963315

RESUMO

A method is described for the preparation of copper(II)-modified keratin-capped gold nanoclusters (AuNCs) with adjustable Au/Cu molar ratio through a two-step synthetic route. The introduction of Cu(II) is known to cause quenching of the fluorescence of such AuNCs. It is found, however, that the Cu(II) loaded AuNC (AuNC-Cu2+) display strongly enhanced peroxidase-like activity and improved chemical stability. This is assumed to be due to the synergistic effect of the gold and copper atoms and in contrast to the single components (pure AuNCs and copper ions). The kinetic parameters of the new peroxidase mimic show a higher Kcat value (12.1 × 10-4 s-1) and a lower Km value (53 µM) for H2O2 (compared to those of conventional AuNCs). The catalytic activity is stable and remains essentially unchanged after two months. The interactions of AuNCs with Cu(II) were characterized by fluorescence spectroscopy, UV-vis spectroscopy and X-ray photoelectron spectroscopy. Based on these findings, a glucose colorimetric assay at 452 nm was developed that has a detection range from 1.6 to 800 µM and a 0.26 µM detection limit. Graphical abstract Copper ion-modified keratin-capped gold nanoclusters (AuNC-Cu2+) exhibit enhanced peroxidase-like activity owing to the synergistic effect of the gold and copper atoms which is in contrast to pure AuNCs.


Assuntos
Materiais Biomiméticos/química , Colorimetria/métodos , Cobre/química , Glucose/análise , Ouro/química , Queratinas/química , Peroxidase/metabolismo , Humanos , Cinética , Limite de Detecção , Nanopartículas Metálicas/química
8.
Int J Mol Sci ; 20(14)2019 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-31323736

RESUMO

OBJECTIVE: Familial hypercholesterolemia (FH) is a dominant inherited disease caused mainly by low-density lipoprotein receptor (LDLR) gene mutations. To different extents, both heterozygous and homozygous FH patients develop premature coronary heart disease (CHD). However, most of the experimental animal models with LDLR deficiency could not fully recapitulate FH because they develop hyperlipidemia and atherosclerosis only in homozygous, but not in heterozygous, form. In the current study, we investigated the responsiveness of the LDLR+/- hamster to dietary cholesterol and whether plasma cholesterol levels were positively associated with the severity of atherosclerosis. Approach and Methods: wild type WT and LDLR+/- hamsters were fed a high fat diet with different cholesterol contents (HCHF) for 12 or 16 weeks. Plasma lipids, (apo)lipoproteins, and atherosclerosis in both the aorta and coronary arteries were analyzed. After a HCHF diet challenge, the levels of total cholesterol (TC) in WT and LDLR+/- hamsters were significantly elevated, but the latter showed a more pronounced lipoprotein profile, with higher cholesterol levels that were positively correlated with dietary cholesterol contents. The LDLR+/- hamsters also showed accelerated atherosclerotic lesions in the aorta and coronary arteries, whereas only mild aortic lesions were observed in WT hamsters. CONCLUSIONS: Our findings demonstrate that, unlike other rodent animals, the levels of plasma cholesterol in hamsters can be significantly modulated by the intervention of dietary cholesterol, which were closely associated with severity of atherosclerosis in LDLR+/- hamsters, suggesting that the LDLR+/- hamster is an ideal animal model for FH and has great potential in the study of FH and atherosclerosis-related CHD.


Assuntos
Aterosclerose/sangue , Aterosclerose/patologia , Colesterol na Dieta , Hiperlipidemias/sangue , Hiperlipidemias/patologia , Hiperlipoproteinemia Tipo II/sangue , Hiperlipoproteinemia Tipo II/patologia , Animais , Aterosclerose/metabolismo , Colesterol/sangue , Cricetinae , Feminino , Hiperlipidemias/metabolismo , Hiperlipoproteinemia Tipo II/metabolismo , Masculino , Receptores de LDL/deficiência , Receptores de LDL/metabolismo
9.
Int J Mol Sci ; 20(23)2019 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-31779098

RESUMO

Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a key role in cholesterol homeostasis and atherogenesis. However, there are only limited rodent models, with a functional low-density lipoprotein receptor (LDLR) pathway and cholesteryl ester transfer protein (CETP) to evaluate the drug candidates targeting the PCSK9/LDLR pathway, that are translatable to humans. Here, by using our recently generated LDLR heterozygote (Ldlr+/-) hamster model with functional LDLR pathway and CETP function, we seek to evaluate the effect of a PCSK9 antibody, evolocumab, on dyslipidemia and atherosclerosis compared with ezetimibe, an effective inhibitor of cholesterol absorption, as a positive therapeutic control. We show that the plasma levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglyceride (TG) were significantly increased in Ldlr+/- hamsters fed a high-fat high-cholesterol (HFHC) diet; therefore, areas of atherosclerotic lesion in the aorta were obviously increased and positively correlated with plasma LDL-C and TC. Circulating free PCSK9 was downregulated by the HFHC diet and was undetectable in the evolocumab treated group, as expected. Most importantly, either evolocumab or ezetimibe treatment prevented HFHC diet-induced hyperlipidemia and subsequent atherosclerotic plaque formation. The results indicate that Ldlr+/- hamsters fed an HFHC diet represent an ideal rodent model to evaluate drug candidates that affect LDLR pathways.


Assuntos
Anticorpos Monoclonais Humanizados/administração & dosagem , Aterosclerose/tratamento farmacológico , Ezetimiba/administração & dosagem , Hiperlipidemias/tratamento farmacológico , Receptores de LDL/deficiência , Animais , Anticorpos Monoclonais Humanizados/farmacologia , Aterosclerose/induzido quimicamente , Aterosclerose/genética , LDL-Colesterol/sangue , Cricetinae , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Ezetimiba/farmacologia , Heterozigoto , Humanos , Hiperlipidemias/induzido quimicamente , Hiperlipidemias/genética , Masculino , Inibidores de PCSK9 , Resultado do Tratamento , Triglicerídeos
10.
Anal Chem ; 89(10): 5230-5237, 2017 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-28436659

RESUMO

In this work, we propose fluorescence and scattering light cross-correlation spectroscopy (FSCCS) based on laser confocal configuration using silver nanoparticle (SNPs) and Alexa Fluor 488 (Alexa) as probe pairs. FSCCS is a single molecule (particle) method, and its principle is similar to that of fluorescence cross-correlation spectroscopy (FCCS). We established the setup of FSCCS using single wavelength laser and developed an immunoassay model of FSCCS. The reliability and adaptability of FSCCS method were evaluated by homogeneous sandwich immunoassay mode. In the study, liver cancer biomarker alpha-fetoprotein (AFP) was used as an assay model, two different antibodies were labeled with SNPs and fluorophore Alexa Fluor 488, respectively. In the optimal conditions, the linear range of AFP covers 5 pM to 580 pM and the detection limit is 3.1 pM. This method was successfully applied for direct determination of AFP levels in human serum samples, and the obtained results were in good agreement with data obtained via ELISAs. The advantage of this method lies in its simplicity, attractive SNPs probes, high sensitivity and selectivity and high efficiency. We believe that FSCCS method exhibits promising potential applications in homogeneous bioassays and study on the molecular interaction and nanoparticle-molecule interaction.


Assuntos
Espectrometria de Fluorescência/métodos , alfa-Fetoproteínas/análise , Biomarcadores Tumorais/sangue , Humanos , Hidrazinas/química , Imunoensaio , Limite de Detecção , Neoplasias Hepáticas/diagnóstico , Nanopartículas Metálicas/química , Prata/química , alfa-Fetoproteínas/imunologia
11.
Plant Dis ; 101(5): 726-733, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-30678568

RESUMO

A new partitivirus named Lentinula edodes partitivirus 1 (LePV1) was isolated from a diseased L. edodes strain with severe degeneration of the mycelium and imperfect browning in bag cultures. The nucleotide sequences of LePV1 dsRNA-1 and dsRNA-2 were determined; they were 2,382 bp and 2,245 bp in length, and each contained a single ORF encoding RNA-dependent RNA polymerase (RdRp) and coat protein (CP), respectively. The purified virus preparation contained isometric particles 34 nm in diameter encapsidating these dsRNAs. Phylogenetic analyses showed LePV1 to be a new member of Betapartitivirus, with the RdRp sequence most closely related to Grapevine partitivirus. RT-PCR analysis showed that 27 of the 56 Chinese L. edodes core collection strains carry LePV1, with the virus being more common in wild strains than cultivated strains. In addition, qPCR analysis suggested that coinfection with L. edodes mycovirus HKB (LeV-HKB) could increase replication of the RdRp gene of LePV1. This study may be essential for the development of more accurate disease diagnostics and the formulation of control strategies for viral diseases in L. edodes.

12.
Analyst ; 140(4): 1207-14, 2015 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-25526365

RESUMO

In this paper, a sensitive and microscale method for drug screening is described using single molecule spectroscopy fluorescence correlation spectroscopy (FCS). The principle of this method is mainly based on the competition of candidate drugs to the fluorescent probe-target complexes and the excellent capacity of FCS for sensitively distinguishing the free fluorescent probes and the fluorescent probe-target complexes in solution. In this study, the screening of protein kinase inhibitors was used as a model, tyrosine-protein kinase ABL1 was used as a target and a known inhibitor dasatinib derivative labeled with a fluorescent dye was used as a fluorescent affinity probe. We firstly established the theoretical model of drug screening based on the binding process of fluorescent probes and targets, the competition of candidate drugs to the fluorescent probe-target complexes and FCS theory. Then, the dasatinib derivatives were synthesized and labeled with the fluorescent dye Alexa 488, and the binding and dissociation processes of Alexa 488-dasatinib and ABL1 were systematically investigated. The dissociation constant and the dissociation rate for the Alexa 488-dasatinib-ABL1 complex were determined. Finally, the established method was used to screen candidate drugs. The dissociation constants of ABL1 kinase to six known drugs for treating chronic myeloid leukemia (CML) were evaluated and the results obtained are well consistent with the reported values. Furthermore, a homemade chip with micro-wells was successfully utilized in FCS measurements as the carrier of samples, and the sample requirements were only 1-2 µL in this case. Our results demonstrated that the drug screening method described here is universal, sensitive and shows small sample and reagent quantity requirements. We believe that this method will become a high throughput platform for screening of small molecule drugs.


Assuntos
Ensaios de Seleção de Medicamentos Antitumorais/métodos , Corantes Fluorescentes/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-abl/antagonistas & inibidores , Pirimidinas/metabolismo , Tiazóis/metabolismo , Antineoplásicos/farmacologia , Dasatinibe , Corantes Fluorescentes/química , Humanos , Hidrazinas/química , Hidrazinas/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Proteínas Proto-Oncogênicas c-abl/metabolismo , Pirimidinas/química , Espectrometria de Fluorescência/métodos , Tiazóis/química
13.
Gastric Cancer ; 18(4): 729-39, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25240408

RESUMO

BACKGROUND: MiR-125b functions as an oncogene in many cancers; however, its clinical significance and molecular mechanism in gastric cancers have never been sufficiently investigated. Here, we elucidated the functions and molecular regulated pathways of MiR-125b in gastric cancer. METHODS: We investigated MiR-125b expression in fresh tissues from 50 gastric cancer patients and 6 gastric cancer cell lines using RT-PCR, and explored its prognostic value by hybridizing MiR-125b in situ for 300 clinical gastric tumor tissues with pathological diagnosis and clinical parameters. The effects of MiR-125b on gastric cancer cells and downstream target genes and proteins were analyzed by MTT, transwell assay, RT-PCR, and western blot on the basis of silencing MiR-125b in vitro. Luciferase reporter plasmid was constructed to demonstrate MiR-125b's direct target. RESULTS: MiR-125b was upregulated in gastric cancer tissues and cell lines, and significantly promoted cellular proliferation, migration, and invasion by downregulating the expression of PPP1CA and upregulating Rb phosphorylation. MiR-125b expression was significantly correlated with tumor size and depth of invasion, lymph nodes, distant metastasis, and TNM stage. The high-MiR-125b-expression group had a significantly poorer prognosis than the low-expression group (P < 0.05) in stages I, II, and III, and the 5-year survival rate in of the high-expression group was significantly lower than that of the low-expression group. CONCLUSIONS: MiR-125b functions as an oncogene by targeting downregulated PPP1CA and upregulated Rb phosphorylation in gastric cancer. MiR-125b not only promotes cellular proliferation, migration, and invasion in vitro, but also acts as an independent prognostic factor in gastric cancer.


Assuntos
Movimento Celular , Regulação Neoplásica da Expressão Gênica/genética , MicroRNAs/genética , Proteína Fosfatase 1/metabolismo , Proteína do Retinoblastoma/metabolismo , Transdução de Sinais , Neoplasias Gástricas/patologia , Adulto , Idoso , Western Blotting , Linhagem Celular , Proliferação de Células/genética , Feminino , Humanos , Hibridização In Situ , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Prognóstico , RNA Interferente Pequeno , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Neoplasias Gástricas/genética , Neoplasias Gástricas/mortalidade , Análise Serial de Tecidos , Transfecção
14.
Haematologica ; 99(12): 1834-45, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25193962

RESUMO

Germinal center lymphoma is a heterogeneous human lymphoma entity. Here we report that constitutive activity of SHP2 (PTPN11) and its downstream kinase ERK is essential for the viability of germinal center lymphoma cells and disease progression. Mechanistically, SHP2/ERK inhibition impedes c-Myc transcriptional activity, which results in the repression of proliferative phenotype signatures of germinal center lymphoma. Furthermore, SHP2/ERK signaling is required to maintain the CD19/c-Myc loop, which preferentially promotes survival of a distinct subtype of germinal center lymphoma cells carrying the MYC/IGH translocation. These findings demonstrate a critical function for SHP2/ERK signaling upstream of c-Myc in germinal center lymphoma cells and provide a rationale for targeting SHP2 in the therapy of germinal center lymphoma.


Assuntos
Centro Germinativo/patologia , Cadeias Pesadas de Imunoglobulinas/genética , Linfoma/patologia , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 11/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Translocação Genética/genética , Apoptose , Western Blotting , Ciclo Celular , Proliferação de Células , Citometria de Fluxo , Imunofluorescência , Centro Germinativo/metabolismo , Humanos , Técnicas Imunoenzimáticas , Imunoprecipitação , Linfoma/genética , Linfoma/metabolismo , Proteína Quinase 1 Ativada por Mitógeno/genética , Proteína Quinase 3 Ativada por Mitógeno/genética , Proteína Tirosina Fosfatase não Receptora Tipo 11/antagonistas & inibidores , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , RNA Mensageiro/genética , RNA Interferente Pequeno/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais , Células Tumorais Cultivadas
15.
Zhonghua Bing Li Xue Za Zhi ; 43(8): 516-21, 2014 Aug.
Artigo em Zh | MEDLINE | ID: mdl-25346120

RESUMO

OBJECTIVE: To investigate promoter methylation status of LITAF gene in B-cell lymphoma and to explore transcription regulation of 5-Aza-2'-deoxycytidine (5-Aza-CdR) on LITAF gene. METHODS: One hundred and five paraffin specimens including 54 cases of diffuse large B cell lymphoma (DLBCL), 15 small lymphocytic lymphoma (SLL), 8 mucosa-associated lymphoid tissue lymphoma (MALT) and 6 follicular lymphoma (FL) were included. Five reactive lymphoid hyperplasia samples were collected as control. Methylation status of CpG island in LITAF gene in the specimens and in Raji, Pfeiffer and Daudi cell lines were detected by methylation-specific PCR (MSP). LITAF expression in Raji, Pfeiffer and Daudi cell lines with or without 5-Aza-CdR treatment was detected by Western blot and immunohistochemistry. The inhibitory ratio in the three cell lines was measured by MTT assay. RESULTS: The frequency of LITAF gene methylation in B-cell lymphoma was 89.5% (94/105) . Among them, 3.8% (4/105) showed complete hypermethylation. In control group, however, there was no methylation in CpG island of LITAF gene promoter. The expression of LITAF was recovered or increased along with the cell growth inhibition when the cells exposed to demethylating reagent. CONCLUSIONS: LITAF gene silencing with aberrant CpG methylation is probably one of the critical events to the oncogenesis of B-cell lymphoma, which may have important implications as a candidate marker for diagnosis and target gene therapy.


Assuntos
Ilhas de CpG , Inativação Gênica , Linfoma de Células B/genética , Proteínas Nucleares/genética , Fatores de Transcrição/genética , Adulto , Azacitidina/análogos & derivados , Azacitidina/metabolismo , Linhagem Celular Tumoral , Metilação de DNA , Decitabina , Humanos , Linfoma de Células B/metabolismo , Linfoma de Zona Marginal Tipo Células B/genética , Linfoma Difuso de Grandes Células B/genética , Proteínas Nucleares/metabolismo , Reação em Cadeia da Polimerase , Regiões Promotoras Genéticas , Fatores de Transcrição/metabolismo
16.
Eur J Prev Cardiol ; 31(6): 658-666, 2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-37966902

RESUMO

AIMS: Cardiovascular health (CVH) has been proven to reduce cardiovascular disease burden and mortality, but data are lacking regarding cardiac arrhythmias. The aim of this study was to assess the association between CVH metrics and atrial fibrillation/flutter (AF), ventricular arrhythmias, and bradyarrhythmias. METHODS AND RESULTS: This study analysed data from the Atherosclerosis Risk in Communities (ARIC) cohort, with participants recruited from four different communities across the United States. Cardiovascular health metrics were scored at baseline (1987-89) following the American Heart Association's recommendations and categorized as poor, intermediate, or ideal. Arrhythmia episodes were diagnosed by International Classification of Diseases (ICD)-9 code. Adjusted associations were estimated using Cox models and event rates and population attributable fractions were calculated by CVH metrics category. The study population consisted of 13 078 participants, with 2548 AF, 1363 ventricular arrhythmias, and 706 bradyarrhythmias occurred. The adjusted hazard ratios (HRs) for ideal (vs. poor) CVH metrics were 0.59 [95% confidence interval (CI): 0.50-0.69] for AF, 0.38 (95% CI: 0.28-0.51) for ventricular arrhythmias, and 0.70 (95% CI: 0.51-0.97) for bradyarrhythmia. The risk of incident arrhythmias decreased steadily as the CVH metrics improved from 0 to 14 scores. The adjusted population attributable fractions were calculated to be 29.9% for AF, 54.4% for ventricular arrhythmias, and 21.9% for bradyarrhythmia, respectively. The association between CVH metrics and incident arrhythmias was also seen in people who remained free of coronary heart disease over the follow-up. CONCLUSION: Achieving ideal CVH metrics recommendations by AHA in midlife was associated with a lower risk of incident arrhythmias later in life.


Intermediate and ideal levels of cardiovascular health (CVH) metrics are associated with a markedly reduced risk of developing incident arrhythmias, including atrial fibrillation/flutter, ventricular arrhythmias, and bradyarrhythmia, independent of coronary heart disease. A majority of incident arrhythmias could be prevented if the risk profile of the entire population was optimized. These findings emphasize the significance of public health policies that improve CVH to reduce the social and economic burden of arrhythmias.


Assuntos
Fibrilação Atrial , Doenças Cardiovasculares , Sistema Cardiovascular , Humanos , Estados Unidos , Bradicardia , Fatores de Risco , Indicadores de Qualidade em Assistência à Saúde , Doenças Cardiovasculares/epidemiologia , Nível de Saúde
17.
Electrophoresis ; 34(12): 1764-71, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23609013

RESUMO

The bioconjugation of fluorescent quantum dots (QDs) and purification of QDs bioconjugates are of vital importance in bioapplications. In this paper, we systematically investigated the purification efficiency of QDs bioconjugates and their stability during separation process by using size exclusion chromatography (SEC) technique, fluorescence spectroscopy, and fluorescence correlation spectroscopy (FCS). In this study, commercial QDs and fluorescein isothiocyanate (FITC) were used as labeling probes, and bovine serum albumin (BSA) and antibody (Erbitux) were used as mode samples. The covalently linkage and the electrostatic interaction were used in bioconjugation procedures. We systematically studied the effects of certain factors such as the scales of column, loading volume, elution buffer, and separation media on the purification efficiency of QDs bioconjugates by a home-built SEC device. And highly pure and monodisperse QDs bioconjugates could be obtained by SEC purification twice under the optimized conditions. Furthermore, we investigated the stability of QDs bioconjugates in different conjugation ways and purification conditions by FCS, and found that the stability of bioconjugates were poor when electrostatic binding mode was used. We also observed that Sephacryl S300 HR (separation range for globular proteins: 1 × 10(4) -1.5 × 10(6) Da) was the best choice for purifying the vast majority of QDs-bioconjugates. Our work described here will be constructive to popularization and applications of QDs in life science.


Assuntos
Cromatografia em Gel/métodos , Nanoconjugados/química , Pontos Quânticos , Estabilidade de Medicamentos , Nanoconjugados/análise , Porosidade , Proteínas/química , Ultrafiltração
18.
Luminescence ; 28(3): 392-400, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-22696455

RESUMO

In this study, we report for the first time a one-pot approach for the synthesis of new CdSeTeS quaternary-alloyed quantum dots (QDs) in aqueous phase by microwave irradiation. CdCl2 was used as a Cd precursor during synthesis, NaHTe and NaHSe were used as Te and Se precursors and mercaptopropionic acid (MPA) was used as a stabilizer and source of sulfur. A series of quaternary-alloyed QDs of different sizes were prepared. CdSeTeS QDs exhibited a wide emission range from 549 to 709 nm and high quantum yield (QY) up to 57.7 %. Most importantly, the quaternary-alloyed QDs possessed significantly long fluorescence lifetimes > 100 ns as well as excellent photostability. Results of high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDX) and powder X-ray diffraction (XRD) spectroscopy showed that the nanocrystals possessed a quaternary alloy structure with good crystallinity. Fluorescence correlation spectroscopy (FCS) showed that QDs possessed good water solubility and monodispersity in aqueous solution. Furthermore, CdSeTeS QDs were modified with alpha-thio-omega-carboxy poly(ethylene glycol) (HS-PEG-COOH) and the modified QDs were linked to anti-epidermal growth factor receptor (EGFR) antibodies. QDs with the EGFR antibodies as labeling probes were successfully applied to targeted imaging for EGFR on the surface of SiHa cervical cancer cells. We believe that CdSeTeS QDs can become useful probes for in vivo targeted imaging and clinical diagnosis.


Assuntos
Ligas/química , Neoplasias/química , Pontos Quânticos/química , Ligas/síntese química , Linhagem Celular Tumoral , Humanos , Micro-Ondas , Neoplasias/diagnóstico , Espectrometria por Raios X , Difração de Raios X
19.
Heliyon ; 9(8): e18607, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37576192

RESUMO

Aimed at the preparation of bimetallic composites by using a liquid-liquid compound casting method with a sound interface, this study focused on the interface evolution with an increase in the pouring time interval. The results revealed that the melt mixing occurred when the pouring interval was 3 s. The transition zone appeared at the interface when the pouring interval was 10 s, and a good metallurgical bond was obtained. When the pouring interval was 20 s, a discontinuous oxide layer appeared at the interface. The oxide layer gap formed a channel for the transport of the SiC particles.

20.
Virology ; 582: 71-82, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37030155

RESUMO

Incidence and banding patterns of virus-like dsRNA elements in 215 Chinese genetically diverse Lentinula edodes strains collected from wide geographic distribution (or producing areas) were first investigated, and 17 viruses were identified including eight novel viruses. The results revealed a 63.3% incidence of dsRNA elements in the cultivated strains and a 67.2% incidence in the wild strains. A total of 10 distinguishable dsRNAs ranging from 0.6 to 12 kbp and 12 different dsRNA patterns were detected in the positive strains. The molecular information of these dsRNA elements was characterized, and the molecular information of the other 12 different viral sequences with (+) ssRNA genome was revealed in four L. edodes strains with complex dsRNA banding patterns. RT-PCR was also done to verify the five dsRNA viruses and 12 (+) ssRNA ones. The results presented may enrich our understanding of L. edodes virus diversity, and will promote further research on virus-host interactions. IMPORTANCE: Viral infections involve complicated interactions including benign, harmful or possibly beneficial to hosts. Sometimes environment could lead to a transition in lifestyles from persistent to acute, resulting in a disease phenotype. The quality of spawn, such as the vulnerability to infection of viruses, is therefore important for mushroom production. Lentinula edodes, a wood rot basidiomycete fungus, was widely cultivated in the world for its edible and medicinal properties. In this study, the profile of dsRNA elements from Chinese genetically diverse L. edodes strains collected from wide geographic distribution or producing areas was first investigated. The molecular information of the dsRNA elements was characterized. Additionally, 12 different viral sequences with (+) ssRNA genome from four L. edodes strains with complex dsRNA banding patterns were identified. The results presented here will broaden our knowledge about mushroom viruses, and promote further studies of L. edodes production and the interaction between viruses and L. edodes.


Assuntos
Micovírus , Cogumelos Shiitake , Micovírus/genética , Micovírus/isolamento & purificação , Fenótipo , Prevalência , RNA de Cadeia Dupla/genética , Cogumelos Shiitake/genética , Cogumelos Shiitake/virologia , China
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