Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 25
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Molecules ; 24(22)2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31703405

RESUMO

A simple, sensitive and effective magnetic solid-phase extraction (MSPE) technique was developed for the extraction of pyrethroid pesticides from environmental water samples, followed by gas chromatography tandem triple quadrupole mass spectrometry determination. An adsorbent of magnetic zeolitic imidazolate framework-8@deep eutectic solvent (M-ZIF-8@DES) was prepared using deep eutectic solvent coated on the surface of M-ZIF-8. The features of M-ZIF-8@DES were confirmed by material characterizations, and the results indicated that M-ZIF-8@DES has a good magnetism (61.3 emu g-1), a decent surface area (96.83 m2 g-1) and pore volume (0.292 mL g-1). Single factor experiments were carried out to investigate the effect of different conditions on the performance of MSPE. Under the optimal conditions, the developed method performs good linearity (R2 ≥ 0.9916) in the concentration range of 1-500 µg L-1. The limits of detection were in the range of 0.05-0.21 µg L-1 (signal/noise = 3/1). The intraday relative standard deviation (RSD) and interday RSD were less than 9.40%. Finally, the proposed technique was applied for the determination of pyrethroid pesticides in environmental water samples. This work shows the potential of DES-modified metal-organic frameworks for different sample pretreatment techniques.

2.
EBioMedicine ; 47: 563-577, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31501076

RESUMO

BACKGROUND: This study aims to evaluate the quality of preclinical data, determine the effect sizes, and identify experimental measures that inform efficacy using mesenchymal stromal (or stem) cells (MSC) therapy in animal models of rheumatoid arthritis (RA). METHODS: Literature searches were performed on MSC preclinical studies to treat RA. MSC treatment effect sizes were determined by the most commonly used outcome measures, including paw thickness, clinical score, and histological score. FINDINGS: A total of 48 studies and 94 treatment arms were included, among which 42 studies and 79 treatment arms reported that MSC improved outcomes. The effect sizes of RA treatments using MSC, when compared to the controls, were: paw thickness was ameliorated by 53.6% (95% confidence interval (CI): 26.7% -80.4%), histological score was decreased by 44.9% (95% CI: 33.3% -56.6%), and clinical score was decreased by 29.9% (95% CI: 16.7% -43.0%). Specifically, our results indicated that human umbilical cord derived MSC led to large improvements of the clinical score (-42.1%) and histological score (-51.4%). INTERPRETATION: To the best of our knowledge, this meta-analysis is to quantitatively answer whether MSC represent a robust RA treatment in animal models. It suggests that in preclinical studies, MSC have consistently exhibited therapeutic benefits. The findings demonstrate a need for considering variations in different animal models and treatment protocols in future studies using MSC to treat RA in humans to maximise the therapeutic gains in the era of precision medicine. FUNDS: NIH [1DP2CA195763], Baylx Inc.: BI-206512, NINDS/NIH Training Grant [Award# NS082174].

3.
Crit Rev Anal Chem ; : 1-13, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31423806

RESUMO

Developing a rapid sample pretreatment method with high enrichment capability and selectivity is important for developing novel analytical techniques in food and environmental safety monitoring. Metal-organic frameworks (MOFs) are multifunctional three-dimensional materials that can be self-assembly prepared from organic ligands and inorganic metal ions or a metal cluster. MOFs have high specific surface areas, good adsorption performance, tunable porosity, and modifiable structures that can be deliberately modulated. They have been widely applied in photoelectrocatalysis, adsorption/separation, drug delivery, sensor detection, and more, because of their superparamagnetism, rapid adsorption/separation, and reusability. As effective adsorbents, magnetic MOFs (MMOFs) have attracted enomous attentions in analytical chemistry and have been used in sample collection and pre-enrichment, solid-phase extraction, and solid-phase microextraction in recent years. In this review, we summarize recent developments in the preparation of MMOFs, understanding of their structural characteristics and adsorption mechanisms, and their applications in food quality/safety and pretreatment. Future prospects in research and development are also discussed.

4.
Ecotoxicol Environ Saf ; 183: 109546, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31437727

RESUMO

A ß-cyclodextrin-functionalized magnetic zinc-metal organic framework (M-MOF/ß-CD) was synthesized via a facile one-pot reaction. M-MOF/ß-CD was used as a magnetic porous absorbent for the extraction and determination of prochloraz and three triazole fungicides in vegetable samples. M-MOF/ß-CD was prepared by creating MOF layers on the surface of a Fe3O4-graphene oxide (GO) nanocomposite and bonding them with ß-CD molecules. Characterization suggested that a 3D porous structure was formed, with M-MOF/ß-CD exhibiting high superparamagnetism and a large surface area. As a new strategy, integrating MOFs with Fe3O4-GO could improve their water-resistance and mechanical strength by providing a rigid nanosupport interface. Combining M-MOF and ß-CD resulted in excellent selective adsorption capacities for prochloraz and three triazole fungicides. The static adsorption process was evaluated and the results were in good agreement with the Freundlich model. Subsequently, M-MOF/ß-CD was applied to extracting prochloraz and triazole fungicides from tomato and lettuce vegetables, followed by HPLC-MS/MS determination. The limits of detection for the above fungicides were found to be 0.25-1.0 µg/L at a signal-to-noise ratio of 3, with spiked recoveries of 74.13%-119.83%, indicating that M-MOF/ß-CD was promising for application to the extraction and determination of fungicides in complex matrices.


Assuntos
Fungicidas Industriais/análise , Imidazóis/análise , Nanopartículas de Magnetita/química , Estruturas Metalorgânicas/química , Triazóis/análise , Verduras/química , beta-Ciclodextrinas/química , Adsorção , Grafite/química , Limite de Detecção , Nanocompostos/química , Porosidade , Reprodutibilidade dos Testes , Propriedades de Superfície
5.
Molecules ; 24(15)2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31362458

RESUMO

As persistent organic pollutants, dichlorodiphenyltrichloroethanes (DDTs) and their metabolites pose considerable risks to human health and the environment. Therefore, monitoring DDTs in the environment is essential. Here, we developed a green, simple, and effective magnetic solid-phase extraction (MSPE) method coupled with gas chromatography tandem triple-quadrupole mass spectrometry to determine the DDT content of environmental water samples. A magnetic ionic liquid (IL) adsorbent was developed based on a modified magnetic multiwalled carbon nanotube/zeolitic imidazolate framework-8 (MM/ZIF-8/IL), synthesized by immobilizing the IL on the surface of MM/ZIF-8. We confirmed successful synthesis of MM/ZIF-8/IL by material characterization, and our results suggested that the MM/ZIF-8/IL had a high Brunauer-Emmett-Teller surface area (159.9 m2 g-1), good thermostability (<800 °C), and a high degree of superparamagnetism (52.9 emu g-1). Several experimental conditions affecting the MSPE efficiency were optimized. Under the best conditions, good detection linearity was achieved (0.5-500 µg L-1) with determination coefficients ranging from 0.9927 to 0.9971. The lower limits of detection (0.0016-0.0072 µg L-1) also had good precision, having an intraday relative standard deviation (RSD) ≤ 6.5% and an interday RSD ≤ 8.9%. Finally, we used the as-developed method to determine DDT levels in environmental water samples.


Assuntos
DDT/química , DDT/isolamento & purificação , Líquidos Iônicos , Magnetismo , Nanotubos de Carbono , Extração em Fase Sólida , Poluentes Químicos da Água , Nanotubos de Carbono/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Zeolitas/química
6.
Nanomaterials (Basel) ; 9(7)2019 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-31323858

RESUMO

Molecular imprinting technology (MIT), also known as molecular template technology, is a new technology involving material chemistry, polymer chemistry, biochemistry, and other multi-disciplinary approaches. This technology is used to realize the unique recognition ability of three-dimensional crosslinked polymers, called the molecularly imprinted polymers (MIPs). MIPs demonstrate a wide range of applicability, good plasticity, stability, and high selectivity, and their internal recognition sites can be selectively combined with template molecules to achieve selective recognition. A molecularly imprinted fluorescence sensor (MIFs) incorporates fluorescent materials (fluorescein or fluorescent nanoparticles) into a molecularly imprinted polymer synthesis system and transforms the binding sites between target molecules and molecularly imprinted materials into readable fluorescence signals. This sensor demonstrates the advantages of high sensitivity and selectivity of fluorescence detection. Molecularly imprinted materials demonstrate considerable research significance and broad application prospects. They are a research hotspot in the field of food and environment safety sensing analysis. In this study, the progress in the construction and application of MIFs was reviewed with emphasis on the preparation principle, detection methods, and molecular recognition mechanism. The applications of MIFs in food and environment safety detection in recent years were summarized, and the research trends and development prospects of MIFs were discussed.

7.
Cell Tissue Res ; 378(2): 155-162, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31209568

RESUMO

In recent years, human umbilical cord blood has emerged as a rich source of stem, stromal and immune cells for cell-based therapy. Among the stem cells from umbilical cord blood, CD45+ multipotent stem cells and CD90+ mesenchymal stem cells have the potential to treat type I diabetes mellitus (T1DM), to correct autoimmune dysfunction and replenish ß-cell numbers and function. In this review, we compare the general characteristics of umbilical cord blood-derived multipotent stem cells (UCB-SCs) and umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) and introduce their applications in T1DM. Although there are some differences in surface marker expression between UCB-SCs and UCB-MSCs, the two cell types display similar functions such as suppressing function of stimulated lymphocytes and imparting differentiation potential to insulin-producing cells (IPCs) in the setting of low immunogenicity, thereby providing a promising and safe approach for T1DM therapy.

8.
Sci Rep ; 9(1): 8919, 2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31222032

RESUMO

A magnetic graphene/polydopamine (MG/PDA) nanocomposite has been prepared and used as sorbent for magnetic dispersive solid-phase extraction (MDSPE) of four benzoylurea insecticides in environmental water samples. The obtained nanocomposites were characterized by transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometry, powder X-ray diffraction, fourier transform infrared spectroscopy, surface area and porosity analysis and thermogravimetric analysis. To investigate the adsorption performance of MG/PDA for target analytes, various parameters affecting the MG/PDA-based MDSPE procedure were optimized. Under the optimal conditions, the established method exhibits good linearity (R2 ≥ 0.9988) in the concentration range 2.5-500 µg L-1. A low limit of detection (0.75 µg L-1, signal/noise = 3:1), a low limit of quantification (2.50 µg L-1, signal/noise = 10:1), and good precision (intraday relative standard deviation ≤3.6%, interday relative standard deviation ≤4.5%) are also achieved. Finally, the simple, fast, and sensitive sample preparation technique was successfully used to determine benzoylurea insecticides in environmental water samples.

9.
J Sep Sci ; 42(7): 1451-1458, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30677235

RESUMO

We present a simple method for the fabrication of a magnetic amino-functionalized zinc metal-organic framework based on a magnetic graphene oxide composite. The resultant framework exhibited a porous 3D structure, high surface area and good adsorption properties for nitrogen-containing heterocyclic fungicides. The adsorption process and capacity indicated that the primary adsorption mechanism might be hydrogen bonding and π-π conjugation. In addition, an optimized protocol for magnetic solid phase extraction was developed (such as adsorbent content, pH, and desorption solvent), and utilized for the extraction of nitrogen-containing heterocyclic fungicides from vegetable samples. Quantitation by high performance liquid chromatography coupled with tandem mass spectrometry offered a detection limit of 0.21-1.0 µg/L (S/N = 3) with correlation coefficients larger than 0.9975. These results demonstrate that magnetic amino-functionalized zinc metal-organic framewor is a promising adsorbent for the extraction and quantitation of nitrogen-containing heterocyclic fungicides.


Assuntos
Fungicidas Industriais/isolamento & purificação , Compostos Heterocíclicos/isolamento & purificação , Alface/química , Estruturas Metalorgânicas/química , Nitrogênio/isolamento & purificação , Extração em Fase Sólida , Adsorção , Cromatografia Líquida de Alta Pressão , Fungicidas Industriais/química , Grafite/química , Compostos Heterocíclicos/química , Fenômenos Magnéticos , Estruturas Metalorgânicas/síntese química , Nitrogênio/química , Tamanho da Partícula , Propriedades de Superfície , Espectrometria de Massas em Tandem , Zinco/química
10.
Stem Cells Dev ; 28(3): 186-195, 2019 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-30511904

RESUMO

Hematological patients who accept chemotherapy always develop secondary tumor or even die of severe infections. As an important central lymphoid organ, the thymus is frequently damaged during chemotherapy. Previous studies showed that the mesenchymal stem cells (MSCs) can promote the proliferation and repair of epithelial cells in thymus. The purpose of our study is to investigate the reparative effects of human adipose-derived mesenchymal stem cells (hADMSCs) in chemotherapy-treated damaged thymus. Eighty mice were randomly divided into four groups: normal group, model control group, hADMSCs untreated group, and hADMSCs treated group. The mice were injected intraperitoneally with dexamethasone sodium phosphate (Dex 20 mg/kg), except the normal group. Then, the chemotherapy models were obtained after 1 week; the treated group was infused intraperitoneally with hADMSCs, whereas the model control group was injected with equal volumes of normal saline. The hADMSC's infusion day was regarded as day 0. The mice were sacrificed at different time points (days 3, 7, 10, and 14). The pathological structure and the function of the thymus, the recovery of T-lymphocyte subpopulation, and the proportion of regulatory T (Treg) cells in spleen and peripheral blood were detected. Additionally, we transfected hADMSCs by lentivirus with green fluorescent protein (GFP) to confirm whether they home to thymus and detected the expressions of cytokines that are associated with the development of thymus in hADMSCs and thymus. The results of the study showed that the hADMSCs treated group had a more rapid recovery in terms of thymic pathological structure and function. The hADMSCs could home to the damaged thymus and secrete cytokines that played important roles in repairing damaged thymus. The results indicated that hADMSCs could repair the damaged thymus caused by chemotherapy and improve the immune microenvironment, which may be a potential treatment for hematological patients.

11.
Sensors (Basel) ; 18(12)2018 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-30486466

RESUMO

Due to their unique optical properties, narrow size distributions, and good biological affinity, gold nanoparticles have been widely applied in sensing analysis, catalytic, environmental monitoring, and disease therapy. The color of a gold nanoparticle solution and its maximum characteristic absorption wavelength will change with the particle size and inter-particle spacing. These properties are often used in the detection of hazardous chemicals, such as pesticide residues, heavy metals, banned additives, and biotoxins, in food. Because the gold nanoparticles-colorimetric sensing strategy is simple, quick, and sensitive, this method has extensive applications in real-time on-site monitoring and rapid testing of food quality and safety. Herein, we review the preparation methods, functional modification, photochemical properties, and applications of gold nanoparticle sensors in rapid testing. In addition, we elaborate on the colorimetric sensing mechanisms. Finally, we discuss the advantages and disadvantages of colorimetric sensors based on gold nanoparticles, and directions for future development.


Assuntos
Inocuidade dos Alimentos , Ouro/química , Nanopartículas Metálicas/química , Técnicas Biossensoriais/métodos , Colorimetria/métodos
12.
Nanomaterials (Basel) ; 8(7)2018 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-29986430

RESUMO

Monitoring of low levels of chlorsulfuron in environmental water samples is important. Although several detection methods have been developed, they all have some drawbacks, such as being time-consuming, requiring expensive instruments and experienced operators, and consuming large volumes of organic solvents. There is an urgent need for a simple, rapid, and inexpensive detection method for chlorsulfuron. Herein, such a method was developed using anti-aggregation of gold nanoparticles (AuNPs) in the presence of acetamiprid in agricultural irrigation water samples. Aggregation of the AuNPs was induced by acetamiprid, and this produced a distinct color change from Bordeaux red to blue. However, the strong hydrogen bonding interaction between chlorsulfuron and acetamiprid could inhibit AuNP aggregation. The effect of chlorsulfuron on the anti-agglomeration behavior of AuNPs was monitored by ultraviolet⁻visiblespectroscopy (UV-Vis) and the naked eye over a concentration range 0.1⁻100 mg/L. The detection limit for chlorsulfuron was 0.025 mg/L (signal-to-noise ratio of three). This colorimetric method was successfully applied to the determination of chlorsulfuron in spiked tap water and agricultural irrigation water with satisfactory recoveries (76.3%⁻94.2%).

13.
Sensors (Basel) ; 18(5)2018 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-29772778

RESUMO

Various highly sensitive and selective analytical methods have been used to monitor metsulfuron-methyl residue in the environment. However, these methods involve costly instruments and complex, time-consuming operations performed in laboratories. Here, a rapid, convenient, and sensitive colorimetric sensor based on anti-aggregation of gold nanoparticles (AuNPs) is demonstrated for the rapid detection of metsulfuron-methyl in agricultural irrigation water. The AuNPs could be induced to aggregate in the presence of melamine and exhibited a distinct color change from wine-red to blue. The aggregation was suppressed by a strong hydrogen-bonding interaction between metsulfuron-methyl and melamine. The differences of the absorbance at 523 nm (ΔA523) and the color change was linearly related to metsulfuron-methyl concentration over the range 0.1⁻100 mg/L, as observed visually and by UV-vis (Ultraviolet-visible) spectrometry. The detection limit of the sensor was as low as 0.05 mg/L (signal/noise = 3), and was used to determine metsulfuron-methyl in spiked water and in agricultural irrigation water samples. Recoveries were in the range of 71.2⁻100.4%, suggesting that the colorimetric sensor was suitable for the determination of metsulfuron-methyl in agricultural water samples.

14.
J Food Prot ; 81(3): 377-385, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29419334

RESUMO

The present study investigated the concentrations of residues of four groups of pesticides in the People's Republic of China: organophosphorus, carbamate, pyrethroid, and triazine pesticides. Twenty-six pesticides were examined using gas chromatography-tandem mass spectrometry and liquid chromatography-tandem mass spectrometry in 2,169 samples of 12 typical vegetables collected from 15 provinces in China. The results showed that 908 (41.9%) samples were positive, with 133 (6.1%) samples exceeding the limit legal in China. Leafy vegetables showed higher positive rates than fruits and root vegetables. Organophosphorus, carbamate, pyrethroid, and triazine pesticides were found in 11.8, 7.7, 13.9, and 10.9% of the samples, respectively, which provided important information on current concentrations of cumulative assessment group pesticide residues for vegetables in China. Of the positive samples, a slight violation rate of 1.9% for the organophosphorus pesticide category exceeded China's maximum residue limits. Positive rates for chlorpyrifos in celery, pak-choi, and leeks were higher, but fewer exceeded China's maximum residue limits.


Assuntos
Resíduos de Praguicidas/análise , Verduras/química , China , Cromatografia Líquida , Contaminação de Alimentos/análise , Frutas/química , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Folhas de Planta/química , Inquéritos e Questionários
15.
Carbohydr Polym ; 175: 584-591, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-28917904

RESUMO

A novel magnetic copper-based metal-organic framework (M-MOF) was prepared using a Fe4O3-graphene oxide (GO)-ß-cyclodextrin (ß-CD) nanocomposite as the magnetic core and support, and used for adsorption and removal of neonicotinoid insecticide pollutants from aqueous solution. M-MOF characterization suggested that 1Fe4O3-GO-ß-CD consisted of a thin single layer with anchored Fe3O4. The M-MOF was coated on the Fe4O3-GO-ß-CD surface. The M-MOF had a large Brunauer-Emmett-Teller surface area (250.33m2g-1) and high super-paramagnetism with saturation magnetization of 10.47emug-1. Adsorption model analysis showed that the equilibrium data for thiacloprid fitted Langmuir monolayer adsorption and the other insecticides tested showed Freundlich bimolecular layer adsorption. The results show that M-MOF is a promising hybrid adsorbent for rapid removal of neonicotinoid insecticide pollutants from environmental waters.


Assuntos
Grafite/química , Estruturas Metalorgânicas/química , Neonicotinoides/isolamento & purificação , Praguicidas/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , beta-Ciclodextrinas/química , Adsorção , Óxidos
16.
Stem Cells Transl Med ; 5(9): 1162-70, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27381991

RESUMO

UNLABELLED: : Adipose-derived mesenchymal stem cells (AD-MSCs) have been shown to ameliorate hyperglycemia in diabetic animals and individuals. However, little is known about whether AD-MSCs affect lipid metabolism. Here we have demonstrated for the first time that AD-MSC infusion can significantly suppress the increase in body weight and remarkably improve dyslipidemia in db/db obese mice and diet-induced obesity mice. Induction of white fat tissue "browning" and activation of adenosine monophosphate-activated protein kinase and its downstream hormone-sensitive lipase in adipose tissue contribute to the antiobesity and lipid-lowering effects. Thus, AD-MSC infusion holds great therapeutic potential for dyslipidemia and associated cardiovascular diseases. SIGNIFICANCE: Mesenchymal stem cells (MSCs) are considered one of the most promising types of stem cells for translational application because of their rich tissue sources, multilineage differentiation capacity, and easy amplification in vitro and unique immunobiological properties. This study demonstrated that adipose-derived MSCs (AD-MSCs) infusion can significantly suppress the increase in body weight and remarkably improve dyslipidemia in obese mice. Induction of white fat tissue "browning" and activation of adenosine monophosphate-activated protein kinase and its downstream hormone-sensitive lipase in adipose tissue were demonstrated to contribute to the antiobesity and lipid-lowering effects. Thus, AD-MSC infusion holds great therapeutic potential for dyslipidemia.


Assuntos
Tecido Adiposo/citologia , Dislipidemias/metabolismo , Transplante de Células-Tronco Mesenquimais , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Glicemia , Western Blotting , Modelos Animais de Doenças , Imuno-Histoquímica , Lipídeos/sangue , Masculino , Células-Tronco Mesenquimais , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Reação em Cadeia da Polimerase em Tempo Real , Esterol Esterase/metabolismo
17.
Cell Mol Immunol ; 13(3): 369-78, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-25942600

RESUMO

Mesenchymal stem/stromal cells (MSCs) possess some characteristics of immune cells, including a pro-inflammatory phenotype, an immunosuppressive phenotype, antibacterial properties and the expression of Toll-like receptor proteins. Here we show that, similar to immune cells, MSCs retain information from danger signals or environmental stimuli for a period of time. When treated with the pro-inflammatory factors lipopolysaccharide (LPS) or tumor necrosis factor-α (TNF-α), MSCs display increased expression of IL-6, IL-8 and MCP-1. Following re-plating and several rounds of cell division in the absence of stimulating factors, the expression of IL-6, IL-8 and MCP-1 remained higher than in untreated cells for over 7 days. A spike in cytokine secretion occurred when cells were exposed to a second round of stimulation. We primed MSCs with LPS and LPS-primed MSCs had better therapeutic efficacy at promoting skin flap survival in a diabetic rat model than did unprimed MSCs. Finally, we found that several microRNAs, including miR146a, miR150 and miR155, along with the modification of DNA by 5-hydroxymethylcytosine (5hmC), mediate the MSC response to LPS and TNF-α stimulation. Collectively, our data suggest that MSCs have a short-term memory of environmental signals, which may impact their therapeutic potential.


Assuntos
Memória Imunológica , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/metabolismo , Transdução de Sinais , 5-Metilcitosina/análogos & derivados , 5-Metilcitosina/metabolismo , Tecido Adiposo/citologia , Animais , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Quimiocina CCL2/metabolismo , Metilação de DNA/efeitos dos fármacos , Diabetes Mellitus Experimental/patologia , Ensaio de Imunoadsorção Enzimática , Memória Imunológica/efeitos dos fármacos , Imunofenotipagem , Interleucina-6/metabolismo , Interleucina-8/metabolismo , Lipopolissacarídeos/farmacologia , Masculino , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , MicroRNAs/genética , MicroRNAs/metabolismo , Ratos Wistar , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais/efeitos dos fármacos , Retalhos Cirúrgicos/fisiologia , Sobrevivência de Tecidos/efeitos dos fármacos , Fator de Necrose Tumoral alfa/farmacologia
18.
Food Chem ; 190: 1174-1181, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26213092

RESUMO

Chitosan and chitosan oligosaccharides (COS) have been reported to possess various biomedical properties, including antimicrobial activities, immuno-enhancing effects, and anti-tumour activities. COS have attracted considerable interest due to their physicochemical properties, and potential applications in the food and pharmaceutical industries, especially in cancer therapies. This paper describes the preparation of COS and their physicochemical properties, and modification, which aids understanding of their biological activities. Based on the latest reports, several biological and anti-tumour activities of COS will be discussed. The proposed anti-tumour mechanisms of COS are summarised, to provide comprehensive insights into research on the molecular level. Finally, the potential applications and future development of the biopolymer will be discussed.


Assuntos
Quitosana/química , Oligossacarídeos/química , Humanos
19.
Carbohydr Polym ; 137: 75-81, 2016 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-26686107

RESUMO

A novel fluorescence sensing strategy for determination of atrazine in tap water involving direct competition between atrazine and 5-(4,6-dichlorotriazinyl) aminofluorescein (5-DTAF), and which exploits magnetic molecularly imprinted polymer (MMIP), has been developed. The MMIP, based on Fe3O4-chitosan nanoparticles, was synthesized to recognize specific binding sites of atrazine. The recognition capability and selectivity of the MMIP for atrazine and other triazine herbicides was investigated. Under optimal conditions, the competitive reaction between 5-DTAF and atrazine was performed to permit quantitation. Fluorescence intensity changes at 515 nm was linearly related to the logarithm of the atrazine concentration for the range 2.32-185.4 µM. The detection limit for atrazine was 0.86µM (S/N=3) and recoveries were 77.6-115% in spiked tap water samples.


Assuntos
Atrazina/química , Quitosana/química , Óxido Ferroso-Férrico/química , Impressão Molecular/métodos , Polímeros/química , Fluorescência
20.
Food Chem ; 181: 347-53, 2015 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-25794760

RESUMO

A simple method based on high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the simultaneous determination of organotins-tri-n-butyltin chloride (TBT), triphenyltin chloride (TPT), dibutyltin dichloride (DBT), and diphenyltin dichloride (DPT)-in plastic food packaging. Samples were prepared by ultrasonic extraction with dichloromethane, followed by dissolution in acetonitrile containing 0.1% formic acid, and purification by an MCX column. The extracts were analyzed by LC-MS/MS in multiple reaction monitoring and positive modes with a C18 column; elution was carried out with a gradient of 0.1% formic acid and methanol containing 0.1% formic acid. The limits of detection for TBT, TPT, DBT, and DPT were 0.1, 0.6, 0.8, and 0.3 µg kg(-1), respectively. The recovery of organotins in spiked samples ranged from 68% to 113% (relative standard deviation: 0.4-4.2%). The proposed method was successfully employed to identify the target analytes in plastic packaging used for milk and cake.


Assuntos
Cromatografia Líquida de Alta Pressão , Embalagem de Alimentos , Compostos Orgânicos de Estanho/análise , Espectrometria de Massas em Tandem , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes , Compostos de Trialquitina/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA