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1.
Biomacromolecules ; 23(3): 779-788, 2022 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-35238555

RESUMO

The gradually depleting fossil resources and the biosafety of bisphenol A have always restricted the green development of the traditional epoxy resin field. In this Article, biomass macromolecule lignin sulfonates are selected as the raw material instead of traditional bisphenol A to prepare lignin-based epoxy resin adhesives. Lignin sulfonates are chemically modified and combined with a cross-linking agent to form lignin-based epoxy resin adhesives with double-interpenetrating-network structures. The resulting lignin-based epoxy adhesive exhibits a maximum tensile shear strength of 11.29 MPa, which is 213% higher than the strength before chemical modification. The tensile shear strength of the adhesive is still 10.13 MPa after 12 h of immersion in water (20 °C), and its tensile shear strength is 9.30 MPa after 12 h of immersion in boiling water (100 °C). The high-temperature and high-humidity environment has no significant effect on the properties of the resulting lignin-based epoxy adhesive.


Assuntos
Adesivos , Resinas Epóxi , Adesivos/química , Resinas Epóxi/química , Ambientes Extremos , Lignina/química , Água
2.
J Transl Med ; 19(1): 323, 2021 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-34330301

RESUMO

BACKGROUND: Pancreatic cancer is a fatal malignancy of the digestive system and the 5-year survival rate remains low. Therefore, new molecular therapeutic targets are required to improve treatments, prognosis, and the survival of patients. N6-methyladenosine (m6A) is the most prevalent reversible methylation in mammalian messenger RNA (mRNA) and has critical roles in the tumorigenesis and metastasis of various malignancies. However, the role of m6A in pancreatic cancer is still unclear. Exploring genetic alterations and functional networks of m6A regulators in pancreatic cancer may provide new strategies for its treatment. METHODS: In this study, we used data from the Cancer Genome Atlas (TCGA) database and other public databases through cBioPortal, LinkedOmics, UALCAN, GEPIA, STRING, and the database for annotation, visualization, and integrated discovery (DAVID) to systematically analyze the molecular alterations and functions of 20 main m6A regulators in pancreatic cancer. RESULTS: We found that m6A regulators had widespread genetic alterations, and that their expression levels were significantly correlated with pancreatic cancer malignancy. Moreover, m6A regulators were associated with the prognosis of pancreatic cancer patients. CONCLUSIONS: m6A regulators play a crucial part in the occurrence and development of pancreatic cancer. Our study will guide further studies of m6A RNA modification in pancreatic cancer and could potentially provide new strategies for pancreatic cancer treatment.


Assuntos
Regulação Neoplásica da Expressão Gênica , Neoplasias Pancreáticas , Animais , Mineração de Dados , Humanos , Metilação , Neoplasias Pancreáticas/genética , RNA Mensageiro/metabolismo
3.
Artigo em Inglês | MEDLINE | ID: mdl-30803968

RESUMO

This study aimed to investigate the genetic characteristics, antibiotic resistance patterns, and novel mechanisms involved in fluoroquinolone (FQ) resistance in commensal Escherichia coli isolates. The E. coli isolates were recovered from a previous clinical study and subjected to antimicrobial susceptibility testing and molecular typing. Known mechanisms of FQ resistance (target site mutations, plasmid-mediated quinolone resistance [PMQR] genes, relative expression levels of efflux pumps and porins) were detected using DNA sequencing of PCR products and real-time quantitative PCR. Whole-genome shotgun sequencing was performed on 11 representative strains to screen for single nucleotide polymorphisms (SNPs). The function of a key SNP (A1541G) was investigated by site-directed mutagenesis and allelic exchange. The results showed that long-term enrofloxacin treatment selected multidrug-resistant (MDR) E. coli isolates in the chicken gut and that these E. coli isolates had diverse genetic backgrounds. Multiple genetic alterations, including double mutations on GyrA (S83L and D87N), a single mutation on ParC (S80I) and ParE (S458E), activation of efflux pumps, and the presence of the QnrS1 protein, contributed to the high-level FQ resistance (enrofloxacin MIC [MICENR] ≥ 128 µg/ml), while the relatively low-level FQ resistance (MICENR = 8 or 16 µg/ml) was commonly mediated by decreased expression of the porin OmpF, besides enhancement of the efflux pumps. No significant relationship was observed between resistance mechanisms and virulence genes. Introduction of the A1541G mutation on aegA was able to increase FQ susceptibility by 2-fold. This study contributes to a better understanding of the development of MDR and the differences underlying the mechanisms of high-level and low-level FQ resistance in E. coli.


Assuntos
Enrofloxacina/farmacologia , Escherichia coli/efeitos dos fármacos , Animais , Galinhas , Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli/genética , Testes de Sensibilidade Microbiana , Mutação/genética , Plasmídeos/genética , Polimorfismo de Nucleotídeo Único/genética , Virulência
4.
Biochem Biophys Res Commun ; 515(4): 558-564, 2019 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-31178144

RESUMO

Radioresistance remains the most challenging issue leading to radiotherapy failure in the treatment of non-small cell lung cancer (NSCLC). The nuclear factor IA (NFIA) is associated with tumor response to treatments in many cancers, but its role in NSCLC radioresistance remains unclear. Here, we established two radioresistant NSCLC cell lines, H226R and H460R, by dose-gradient irradiation to investigate the function of NFIA in NSCLC radioresistance. The results showed a dramatically reduced expression of NFIA in radioresistant cells accompanied with elevated phosphorylation of AKT and ERK, when compared with their parental cells. Overexpression of NFIA restored the sensitivity of radioresistant cells to radiation through increased ionizing radiation (IR)-induced apoptosis and DNA damage by downregulating p-AKT and p-ERK, whereas knockdown of NFIA promoted radioresistance of the parental cells. Our findings suggested that NFIA enhanced cell radiosensitivity by downregulating p-AKT and p-ERK in NSCLC. Our study fills a gap in the field of NFIA and radioresistance, and establishes a mechanistic foundation to improve radiotherapy efficiency in NSCLC patients.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Neoplasias Pulmonares/metabolismo , Fatores de Transcrição NFI/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Tolerância a Radiação , Apoptose , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Proliferação de Células , Reparo do DNA , Relação Dose-Resposta à Radiação , Regulação Neoplásica da Expressão Gênica , Histonas/metabolismo , Humanos , Aceleradores de Partículas , Fosforilação , Radiação Ionizante , Transdução de Sinais , Raios X
5.
BMC Cancer ; 18(1): 611, 2018 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-29848294

RESUMO

BACKGROUND: Activation of c-Met, a receptor tyrosine kinase, induces radiation therapy resistance in non-small cell lung cancer (NSCLC). The activated residual of c-Met is located in lipid rafts (Duhon et al. Mol Carcinog 49:739-49, 2010). Therefore, we hypothesized that disturbing the integrity of lipid rafts would restrain the activation of the c-Met protein and reverse radiation resistance in NSCLC. In this study, a series of experiments was performed to test this hypothesis. METHODS: NSCLC A549 and H1993 cells were incubated with methyl-ß-cyclodextrin (MßCD), a lipid raft inhibitor, at different concentrations for 1 h before the cells were X-ray irradiated. The following methods were used: clonogenic (colony-forming) survival assays, flow cytometry (for cell cycle and apoptosis analyses), immunofluorescence microscopy (to show the distribution of proteins in lipid rafts), Western blotting, and biochemical lipid raft isolation (purifying lipid rafts to show the distribution of proteins in lipid rafts). RESULTS: Our results showed that X-ray irradiation induced the aggregation of lipid rafts in A549 cells, activated c-Met and c-Src, and induced c-Met and c-Src clustering to lipid rafts. More importantly, MßCD suppressed the proliferation of A549 and H1993 cells, and the combination of MßCD and radiation resulted in additive increases in A549 and H1993 cell apoptosis. Destroying the integrity of lipid rafts inhibited the aggregation of c-Met and c-Src to lipid rafts and reduced the expression of phosphorylated c-Met and phosphorylated c-Src in lipid rafts. CONCLUSIONS: X-ray irradiation induced the aggregation of lipid rafts and the clustering of c-Met and c-Src to lipid rafts through both lipid raft-dependent and lipid raft-independent mechanisms. The lipid raft-dependent activation of c-Met and its downstream pathways played an important role in the development of radiation resistance in NSCLC cells mediated by c-Met. Further studies are still required to explore the molecular mechanisms of the activation of c-Met and c-Src in lipid rafts induced by radiation.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/radioterapia , Neoplasias Pulmonares/radioterapia , Microdomínios da Membrana/metabolismo , Proteínas Proto-Oncogênicas c-met/metabolismo , Quinases da Família src/metabolismo , Células A549 , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Proteína Tirosina Quinase CSK , Carcinoma Pulmonar de Células não Pequenas/patologia , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/efeitos da radiação , Humanos , Neoplasias Pulmonares/patologia , Microdomínios da Membrana/efeitos dos fármacos , Microdomínios da Membrana/efeitos da radiação , Fosforilação/efeitos dos fármacos , Fosforilação/efeitos da radiação , Tolerância a Radiação/efeitos dos fármacos , Radiossensibilizantes/farmacologia , beta-Ciclodextrinas/farmacologia
6.
Biomed Chromatogr ; : e4268, 2018 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-29722050

RESUMO

A simple and reliable LC-MS/MS method was established for simultaneous determination of 12 components from acetylkitasamycin and kitasamycin in swine plasma. The analytes were separated on a Shim-pack VP-ODS column with a 25 min gradient elution using 5 mmol/L ammonium acetate and acetonitrile as the mobile phase at a flow rate of 0.2 mL/min. Identification and quantification were accomplished by electrospray ionization) in positive mode using multiple reaction monitoring. The limits of quantitation of acetylkitasamycin A1 A3 , A13 and kitasamycin A3 , A13 were 3 µg/L, and that of the other eight components was 5 µg/L. The mean recoveries of kitasamycin and acetylkitasamycin ranged from 85.3 to 103.5%. The developed method was successfully applied to a pharmacokinetic study in swine after intravenous (i.v.) and oral (p.o.) administration of acetylkitasamycin. The result showed that the plasma concentrations of acetylkitsamycin components were much higher than that of kitasamycin in swine after i.v. and p.o., in which acetylkitsamycin A4 A5 was the highest component at each time point.

7.
Stem Cells ; 29(10): 1589-600, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21805534

RESUMO

Global analysis of stem/progenitor cells promises new insight into mechanisms that govern self-renewal and cellular potential, an unresolved question of stem/progenitor cell biology. Despite rapid advance of genome-wide profiling methods, the difficulty in cell purification remains a major challenge for global analysis of somatic stem/progenitor cells. Genetic tagging with a reporter provides a powerful tool for identification and isolation of a specific mature cell type; however, for stem/progenitor cells, reporter retention by progeny may be a concern for impurity. Here, we describe a genetic system combining a progenitor cell specific label with a second tag for marking differentiation. We present evidence that differential labeling of neural progenitor cells and their progeny enables prospective purification of these two cell types, whereas isolation based on a single marker compromises the purity of the intended progenitor population. Comparative expression profiling between the purified progenitors and progeny documents a neural progenitor cell transcriptome and uncovers an important role of Tyro3/Axl/Mer receptor tyrosine kinases in the maintenance of neural progenitor cells. This study establishes a general strategy for isolation of somatic stem/progenitor cells and provides a transcriptome database of neural progenitor cells useful for identification of causal factors of neural progenitor cell state, global dissection of epigenetic control of cellular potential, as well as for developing biomarkers or targets of brain cancer stem/initiating cells for therapeutic interventions.


Assuntos
Perfilação da Expressão Gênica , Genes Reporter , Células-Tronco Neurais/citologia , Animais , Proliferação de Células , Córtex Cerebral/citologia , Córtex Cerebral/metabolismo , Proteínas do Olho/genética , Proteínas do Olho/metabolismo , Feminino , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Proteínas de Filamentos Intermediários/genética , Proteínas de Filamentos Intermediários/metabolismo , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Nestina , Células-Tronco Neurais/metabolismo , Neurônios/citologia , Neurônios/metabolismo , Fator de Transcrição PAX6 , Fatores de Transcrição Box Pareados/genética , Fatores de Transcrição Box Pareados/metabolismo , Gravidez , Regiões Promotoras Genéticas , Receptores Proteína Tirosina Quinases/genética , Receptores Proteína Tirosina Quinases/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Proteína Vermelha Fluorescente
8.
Cancer Cell Int ; 12(1): 41, 2012 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-22995409

RESUMO

BACKGROUND: The cancer stem cell (CSC) hypothesis posits that deregulated neural stem cells (NSCs) form the basis of brain tumors such as glioblastoma multiforme (GBM). GBM, however, usually forms in the cerebral white matter while normal NSCs reside in subventricular and hippocampal regions. We attempted to characterize CSCs from a rare form of glioblastoma multiforme involving the neurogenic ventricular wall. METHODS: We described isolating CSCs from a GBM involving the lateral ventricles and characterized these cells with in vitro molecular biomarker profiling, cellular behavior, ex vivo and in vivo techniques. RESULTS: The patient's MRI revealed a heterogeneous mass with associated edema, involving the left subventricular zone. Histological examination of the tumor established it as being a high-grade glial neoplasm, characterized by polygonal and fusiform cells with marked nuclear atypia, amphophilic cytoplasm, prominent nucleoli, frequent mitotic figures, irregular zones of necrosis and vascular hyperplasia. Recurrence of the tumor occurred shortly after the surgical resection. CD133-positive cells, isolated from the tumor, expressed stem cell markers including nestin, CD133, Ki67, Sox2, EFNB1, EFNB2, EFNB3, Cav-1, Musashi, Nucleostemin, Notch 2, Notch 4, and Pax6. Biomarkers expressed in differentiated cells included Cathepsin L, Cathepsin B, Mucin18, Mucin24, c-Myc, NSE, and TIMP1. Expression of unique cancer-related transcripts in these CD133-positive cells, such as caveolin-1 and -2, do not appear to have been previously reported in the literature. Ex vivo organotypic brain slice co-culture showed that the CD133+ cells behaved like tumor cells. The CD133-positive cells also induced tumor formation when they were stereotactically transplanted into the brains of the immune-deficient NOD/SCID mice. CONCLUSIONS: This brain tumor involving the neurogenic lateral ventricular wall was comprised of tumor-forming, CD133-positive cancer stem cells, which are likely the driving force for the rapid recurrence of the tumor in the patient.

10.
Stem Cells ; 28(9): 1581-9, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20629171

RESUMO

Proper development of the mammalian brain requires that neural progenitor cells balance self-renewal and differentiation under precise temporal and spatial regulation, but the underlying mechanisms are not well understood. In this study, we identify Gα subunit as a positive regulator of mammalian neurogenesis, working with the regulator of G protein signaling (RGS)-mediated ephrin-B signaling pathway as two opposing forces to maintain a balance between self-renewal and differentiation in the developing mouse cerebral cortex. Multiple Gα(i) subunits are expressed by cortical neural progenitor cells during the course of cortical neurogenesis. Activation of Gα(i) signaling, through in utero electroporation-mediated expression of wild-type and constitutively active Gα(i) subunits, counteracts the function of ephrin-B in cortical neural progenitors to induce differentiation. Genetic knock-in of an RGS-insensitive G184SGα(i2) causes early cell cycle exit and a reduction of cortical neural progenitor cells and leads to a defect in the production of late born cortical neurons, similar to what is observed in mutant mice with deficiency in ephrin-B reverse signaling pathway. This study reveals a role of Gα subunit in mammalian neurogenesis and uncovers a developmental mechanism, coordinated by the Gα and ephrin-B signaling pathways, for control of the balance between self-renewal and differentiation in neural progenitor cells.


Assuntos
Proliferação de Células , Córtex Cerebral/metabolismo , Células-Tronco Embrionárias/metabolismo , Efrinas/metabolismo , Subunidade alfa Gi2 de Proteína de Ligação ao GTP/metabolismo , Neurogênese , Neurônios/metabolismo , Animais , Ciclo Celular , Células Cultivadas , Córtex Cerebral/embriologia , Eletroporação , Subunidade alfa Gi2 de Proteína de Ligação ao GTP/genética , Camundongos , Camundongos Transgênicos , Proteínas RGS/metabolismo , Transdução de Sinais , Fatores de Tempo
11.
Int J Biol Sci ; 17(2): 635-650, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33613118

RESUMO

Objectives: Radiotherapy has played a limited role in the treatment of non-small cell lung cancer (NSCLC) due to the risk of tumour radioresistance. We previously established the radioresistant non-small cell lung cancer (NSCLC) cell line H460R. In this study, we identified differentially expressed genes between these radioresistant H460R cells and their radiosensitive parent line. We further evaluated the role of a differentially expressed gene, ITGB1, in NSCLC cell radioresistance and as a potential target for improving radiosensitivity. Materials and Methods: The radiosensitivity of NSCLC cells was evaluated by flow cytometry, colony formation assays, immunofluorescence, and Western blotting. Bioinformatics assay was used to identify the effect of ITGB1 and YAP1 expression in NSCLC tissues. Results: ITGB1 mRNA and protein expression levels were higher in H460R than in the parental H460 cells. We observed lower clonogenic survival and cell viability and a higher rate of apoptosis of ITGB1-knockdown A549 and H460R cells than of wild type cells post-irradiation. Transfection with an ITGB1 short hairpin (sh) RNA enhanced radiation-induced DNA damage and G2/M phase arrest. Moreover, ITGB1 induced epithelial-mesenchymal transition (EMT) of NSCLC cells. Silencing ITGB1 suppressed the expression and intracellular translocation of Yes-associated protein 1 (YAP1), a downstream effector of ITGB1. Conclusions: ITGB1 may induce radioresistance via affecting DNA repair and YAP1-induced EMT. Taken together, our data suggest that ITGB1 is an attractive therapeutic target to overcome NSCLC cell radioresistance.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/metabolismo , Integrina beta1/metabolismo , Neoplasias Pulmonares/metabolismo , Tolerância a Radiação , Proteínas de Sinalização YAP/metabolismo , Células A549 , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Reparo do DNA , Transição Epitelial-Mesenquimal , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/radioterapia
12.
Mol Ther Nucleic Acids ; 25: 277-292, 2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34484859

RESUMO

Pancreatic cancer is the deadliest malignancy of the digestive system and is the seventh most common cause of cancer-related deaths worldwide. The incidence and mortality of pancreatic cancer continue to increase, and its 5-year survival rate remains the lowest among all cancers. N6-methyladenine (m6A) is the most abundant reversible RNA modification in various eukaryotic messenger and long noncoding RNAs and plays crucial roles in the occurrence and development of cancers. However, the role of m6A in pancreatic cancer remains unclear. The present study aimed to explore the role of m6A and its regulators in pancreatic cancer and assess its underlying molecular mechanism associated with pancreatic cancer cell proliferation, invasion, and metastasis. Reduced expression of the m6A demethylase, fat mass and obesity-associated protein (FTO), was responsible for the high levels of m6A RNA modification in pancreatic cancer. Moreover, FTO demethylated the m6A modification of praja ring finger ubiquitin ligase 2 (PJA2), thereby reducing its mRNA decay, suppressing Wnt signaling, and ultimately restraining the proliferation, invasion, and metastasis of pancreatic cancer cells. Altogether, this study describes new, potential molecular therapeutic targets for pancreatic cancer that could pave the way to improve patient outcome.

13.
Eur J Med Chem ; 223: 113657, 2021 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-34217060

RESUMO

As a continuation of our research on antimycobacterial agents, a series of novel quinoxaline-1,4-di-N-oxides (QdNOs) containing various nitrogenous heterocyclic moieties at the R6 position were designed and synthesized. Antimycobacterial activities, as well as the cytotoxic effects, of the compounds were assayed. Four compounds (6b, 6f, 6n, and 6o), characterized by 2-carboxylate ethyl or benzyl ester, 6-imidazolyl or 1,2,4-triazolyl, and a 7-fluorine group, exhibited the most potent antimycobacterial activity against M.tb strain H37Rv (MIC ≤ 0.25 µg/mL) with low toxicity in VERO cells (SI = 169.3-412.1). Compound 6o also exhibited excellent antimycobacterial activity in an M.tb-infected macrophage model and was selected for further exploration of the mode of antimycobacterial action of QdNOs. The results showed that compound 6o was capable of disrupting membrane integrity and disturbing energy homeostasis in M.tb. Furthermore, compound 6o noticeably increased cellular ROS levels and, subsequently, induced autophagy in M.tb-infected macrophages, possibly indicating the pathways of QdNOs-mediated inhibition of intracellular M.tb replication. The in vivo pharmacokinetic (PK) profiles indicated that compounds 6o was acceptably safe and possesses favorable PK properties. Altogether, these findings suggest that compound 6o is a promising antimycobacterial candidate for further research.


Assuntos
Antituberculosos/farmacologia , Autofagia/efeitos dos fármacos , Macrófagos/microbiologia , Mycobacterium tuberculosis/efeitos dos fármacos , Quinoxalinas/química , Animais , Antituberculosos/química , Antituberculosos/farmacocinética , Sobrevivência Celular/efeitos dos fármacos , Chlorocebus aethiops , Avaliação Pré-Clínica de Medicamentos , Meia-Vida , Testes de Sensibilidade Microbiana , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Mycobacterium tuberculosis/fisiologia , Óxidos/química , Quinoxalinas/farmacocinética , Quinoxalinas/farmacologia , Ratos , Espécies Reativas de Oxigênio/metabolismo , Relação Estrutura-Atividade , Células Vero
14.
Front Vet Sci ; 8: 638358, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33969036

RESUMO

The depletion profiles of olaquindox and its six major metabolites, including O1 (N 1-deoxyolaquindox), O2 (deoxyolaquindox), O3 (2-carboxamide-3-methylquinoxaline-N 4-oxide), O4 (2-carboxymethylaminocarbonyl-3-methylquinoxaline-N 4-oxide), O5 (2-carboxymethylaminocarbonyl-3-methylquinoxaline), and O6 [3-methyl-quinoxaline-2-carboxylic acid (MQCA)] were studied with a sensitive and accurate HPLC-UV method in pigs and broilers after oral administration of olaquindox at the rate of 50 mg kg-1 feed for 14 consecutive days. Five medicated pigs and six medicated broilers and one control animal for each time point were anesthetized and killed at different time points (6 h and 1, 3, 7, and 14 days for pigs and 6 h and 1, 3, 5, and 7 days for broilers) after ingestion of the medicated feed ceased and samples of muscle, liver, kidney, and fat were collected. The samples were assayed using a liquid chromatographic method. Mean concentrations of O2 (deoxyolaquindox) metabolite residues in all tissues of pigs were higher than other metabolite residues at each time point. MQCA was detected at lower concentrations and eliminated more rapidly than deoxyolaquindox (calculated t 1/2 1.78-2.28 days vs. t 1/2 2.04-2.46 days). The elimination half-lives of deoxyolaquindox residue in broilers' liver and kidney tissues (t 1/2 >4 days) were much longer than those in pigs. Thus, the use of olaquindox in poultry is clearly inappropriate, as significant drug residues will occur without a withdrawal time. The results that deoxyolaquindox occurs at higher concentrations in kidney tissue and is more persistent than other residues in edible tissues of pigs which indicate that deoxyolaquindox is the most relevant marker residue and should be monitored in the routine surveillance of olaquindox-related residues in foods of animal origin.

15.
Lab Chip ; 21(12): 2453-2463, 2021 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-33978043

RESUMO

High-molecular-weight polymeric nanoparticles are critical to increasing the loading efficacy and tuning the release profile of targeted molecules for medical diagnosis, imaging, and therapeutics. Although a number of microfluidic approaches have attained reproducible nanoparticle synthesis, it is still challenging to fabricate nanoparticles from high-molecular-weight polymers in a size and structure-controlled manner. In this work, an acoustofluidic platform is developed to synthesize size-tunable, high-molecular-weight (>45 kDa) poly(lactic-co-glycolic acid)-b-poly(ethylene glycol) (PLGA-PEG) nanoparticles without polymer aggregation by exploiting the characteristics of complete and ultrafast mixing. Moreover, the acoustofluidic approach achieves two features that have not been achieved by existing microfluidic approaches: (1) multi-step (≥2) sequential nanoprecipitation in a single device, and (2) synthesis of core-shell structured PLGA-PEG/lipid nanoparticles with high molecular weights. The developed platform expands microfluidic potential in nanomaterial synthesis, where high-molecular-weight polymers, multiple reagents, or sequential nanoprecipitations are needed.


Assuntos
Nanopartículas , Polímeros , Lipídeos , Microfluídica , Tamanho da Partícula , Polietilenoglicóis
16.
J Neurosci ; 29(23): 7404-12, 2009 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-19515908

RESUMO

Neural progenitor cells in the ventricular zone of the developing mammalian cerebral cortex give rise to specialized cortical cell types via consecutive rounds of proliferation and differentiation, but the mechanisms by which progenitor cell self-renewal and differentiation are regulated during cortical development are not well understood. Here, we show that zinc-finger and homeodomain protein 2 (ZHX2) is specifically expressed in neural progenitor cells during cortical neurogenesis. ZHX2 binds to the cytoplasmic domain of ephrin-B1, which is expressed in cortical neural progenitors and plays a role in neural progenitor cell maintenance. ZHX2 acts as a transcriptional repressor in cell, and its repressor activity is enhanced by coexpression of an ephrin-B1 intracellular domain. Blocking ZHX2 function in cultured neural progenitor cells or in the embryonic cortex causes neuronal differentiation, whereas overexpression of ZHX2 and an ephrin-B1 intracellular domain disrupts the normal differentiation of cortical neural progenitor cells. This study identifies ZHX2 as a novel regulator of neural progenitor cell maintenance and suggests a potential nuclear mechanism of the ephrin-B function in the cortex.


Assuntos
Córtex Cerebral/fisiologia , Efrina-B1/metabolismo , Proteínas de Homeodomínio/metabolismo , Neurogênese , Neurônios/fisiologia , Células-Tronco/fisiologia , Sequência de Aminoácidos , Animais , Células COS , Linhagem Celular , Córtex Cerebral/embriologia , Chlorocebus aethiops , Efrina-B1/genética , Efrina-B2/genética , Humanos , Camundongos , Dados de Sequência Molecular , Neurônios/citologia , Homologia de Sequência de Aminoácidos , Células-Tronco/citologia , Transfecção
17.
Int J Biol Macromol ; 164: 1832-1839, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32758609

RESUMO

The gradual depletion of petroleum is a main challenge restricting the development for the fine chemicals, such as epoxy resin adhesive. In this study, a novel lignin-containing high-performance epoxy resin adhesive is synthesized using lignin as precursor material. Lignin is a unique biomacromolecule with three dimensional network structure, large molecular weight, and aromatic structure. The lignin is simply hydrolyzed and modified by epichlorohydrin to obtain lignin-based epoxy prepolymer. The hydrolysis process effectively reduces the molecular weight and improves the chemical reactivity of lignin, thus increasing the number of modified functional groups and the dispersibility of lignin concurrently. With the introduction of the lignin-based epoxy prepolymers, the shear strength of the adhesive increases obviously and reaches 10.42 MPa, which displays 228% of the shear strength of commercial epoxy resin adhesives. Furthermore, the lignin-containing epoxy resin adhesive still displays excellent mechanical properties in extreme environments, including extreme temperature and high humidity environment.


Assuntos
Adesivos/química , Resinas Epóxi/síntese química , Lignina/química , Resinas Epóxi/química , Ambientes Extremos , Teste de Materiais , Resistência ao Cisalhamento , Propriedades de Superfície , Temperatura
18.
Front Chem ; 8: 598, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32850634

RESUMO

Tuberculosis and fungal infections can pose serious threats to human health. In order to find novel antimicrobial agents, 26 novel quinoxaline-1,4-di-N-oxides containing a thiazolidinone moiety were designed and synthesized, and their antimycobacterial activities were evaluated. Among them, compounds 2t, 2u, 2y, and 2z displayed the most potent antimycobacterial activity against Mycobacterium tuberculosis strain H37Rv (minimal inhibitory concentration [MIC] = 1.56 µg/mL). The antifungal activity of all the compounds was also evaluated against Candida albicans, Candida tropicalis, Aspergillus fumigatus, and Cryptococcus neoformans. Compounds 2t, 2u, 2y, and 2z exhibited potential antifungal activities, with an MIC between 2 and 4 µg/mL. Comparative molecular field analysis (CoMFA: q 2 = 0.914, r 2 = 0.967) and comparative molecular similarity index analysis (CoMSIA: q 2 = 0.918, r 2 = 0.968) models were established to investigate the structure and antimycobacterial activity relationship. The results of contour maps revealed that electronegative and sterically bulky substituents play an important role in the antimycobacterial activity. Electronegative and sterically bulky substituents are preferred at the C7 position of the quinoxaline ring and the C4 position of the phenyl group to increase the antimycobacterial activity. Additionally, more hydrogen bond donor substituents should be considered at the C2 side chain of the quinoxaline ring to improve the activity.

19.
PeerJ ; 8: e8816, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32219034

RESUMO

BACKGROUND: The nuclear factor I (NFI) is a family of transcription factors consisting of four distinct but closely related genes, NFIA, NFIB, NFIC and NFIX, which are important in the development of various tissues and organs in mammals. Recent study results have shown that NFI family may play a critical role in the progression of various human tumors and have been identified as key tumor suppressors and oncogenes for many cancers. However, the expression levels and distinctive prognostic values of the NFI family remain poorly explored in most cancers. MATERIALS AND METHODS: In the present study, the differences in mRNA expression of the NFI family in various cancers were investigated using the Oncomine and TCGA databases, and the mRNA expression, genetic alteration and DNA methylation of the NFI family members in various cancers were examined using cBioPortal for Cancer Genomics. In addition, the prognostic significance of the NFI family was assessed in multiple cancers using the Kaplan-Meier plotter (KM plotter) and SurvExpress databases. RESULTS: The mRNA expression levels in the NFI family were significantly downregulated in most cancers compared with normal tissues and DNA hypermethylation might downregulate the NFI family expression. Although NFIX expression was not downregulated in kidney, colorectal and prostate cancers. Furthermore, NFIB expression was upregulated in gastric cancer. Further survival analyses based on the KM plotter and SurvExpress databases showed dysregulations of the NFI genes were significantly correlated with survival outcomes in breast, lung, and head and neck cancers. Decreased expression levels of NFIA, NFIB and NFIC were associated with poor overall survival (OS) in head and neck cancer. Low mRNA expression of NFIA and NFIB was significantly associated with OS and first progression in lung adenocarcinoma, but not in lung squamous cell carcinoma. In addition, potential correlations between NFI family members and survival outcomes were also observed in liver, esophageal, kidney and cervical cancer. CONCLUSION: The results from the present study indicated certain members of the NFI family could be promising therapeutic targets and novel prognostic biomarkers for human cancers.

20.
Lab Chip ; 20(7): 1298-1308, 2020 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-32195522

RESUMO

Separation of nano/microparticles based on surface acoustic waves (SAWs) has shown great promise for biological, chemical, and medical applications ranging from sample purification to cancer diagnosis. However, the permanent bonding of a microchannel onto relatively expensive piezoelectric substrates and excitation transducers renders the SAW separation devices non-disposable. This limitation not only requires cumbersome cleaning and increased labor and material costs, but also leads to cross-contamination, preventing their implementation in many biological, chemical, and medical applications. Here, we demonstrate a high-performance, disposable acoustofluidic platform for nano/microparticle separation. Leveraging unidirectional interdigital transducers (IDTs), a hybrid channel design with hard/soft materials, and tilted-angle standing SAWs (taSSAWs), our disposable acoustofluidic devices achieve acoustic radiation forces comparable to those generated by existing permanently bonded, non-disposable devices. Our disposable devices can separate not only microparticles but also nanoparticles. Moreover, they can differentiate bacteria from human red blood cells (RBCs) with a purity of up to 96%. Altogether, we developed a unidirectional IDT-based, disposable acoustofluidic platform for micro/nanoparticle separation that can achieve high separation efficiency, versatility, and biocompatibility.


Assuntos
Acústica , Som , Humanos , Dispositivos Lab-On-A-Chip , Transdutores
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