Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Math Biosci Eng ; 16(5): 4692-4707, 2019 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-31499684

RESUMO

Extreme learning machine (ELM) is a kind of learning algorithm for single hidden-layer feedforward neural network (SLFN). Compared with traditional gradient-based neural network learning algorithms, ELM has the advantages of fast learning speed, good generalization performance and easy implementation. But due to the random determination of input weights and hidden biases, ELM demands more hidden neurons and cannot guarantee the optimal network structure. Here, we report a new learning algorithm to overcome the disadvantages of ELM by tuning the input weights and hidden biases through an improved electromagnetism-like mechanism (EM) algorithm called DAEM and Moore-Penrose (MP) generalized inverse to analytically determine the output weights of ELM. In DAEM, three different solution updating strategies inspired by dragonfly algorithm (DA) are implemented. Experimental results indicate that the proposed algorithm DAEM-ELM has better generalization performance than traditional ELM and other evolutionary ELMs.

3.
Sci Total Environ ; 696: 134007, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31465919

RESUMO

The "targeted ecopharmacovigilance (EPV)" strategy emphasizes the control of environmental pollution by high-priority hazardous pharmaceuticals from principal pollution sources especially in areas that are high risk as a result of drug administration. We conducted a prospective empirical study to explore the possibility of using a targeted EPV intervention as an optimized management tool for the control of aquatic pollution by antibiotics, a common type of pharmaceutical residue, in a rural area in China. Because of the notably high levels of ofloxacin in the studied aquatic environment and the well-accepted environmental risks posed by fluoroquinolone residues, ofloxacin was selected as the targeted high-priority antibiotic pollutant. Based on the main sources of antibiotic pollution in the studied rural aquatic environment, which had been traced previously, a five-step targeted EPV intervention was designed and conducted from Feb 2018 to Jan 2019. The results showed that the residual levels of ofloxacin in the studied Chinese rural aquatic environment significantly decreased during the targeted EPV intervention. Importantly, the EPV measures targeting ofloxacin were found to effectively reduce the environmental pollution by other non-targeted antibiotics. The data from a survey of 45 participants (42 residents and 3 clinicians) and 12 program committee members revealed that the targeted EPV intervention was acceptable to both participants and organizers and could be used as an economical and feasible solution for addressing antibiotic pollution in aquatic environments.

4.
Food Funct ; 10(7): 4361-4371, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31276149

RESUMO

The anti-cancer activities of brown algae and some active extracts or components from brown algae have been demonstrated. But the anti-tumor activities of eckol, a new natural phlorotannin derived from marine brown algae, are poorly understood. In order to investigate the in vivo anti-tumor effect and its potential mechanisms of eckol in a sarcoma 180 (S180) xenograft-bearing animal model, S180 xenograft-bearing mice were randomly divided into 4 groups: model control, and eckol low-dose (0.25 mg kg-1), middle-dose (0.5 mg kg-1) and high-dose (1.0 mg kg-1) groups. After eckol administration, the tumor inhibition, tumor tissue histology, thymus index and spleen index were measured. The apoptotic tumor cells were detected using the terminal deoxynucleotidyl transferase mediated dUTP nick end labelling (TUNEL) assay. The protein expression levels of cleaved Caspase-3 and Caspase-9 (two key apoptotic proteins), Bcl-2 and Bax (two key anti-apoptosis-related genes), as well as epidermal growth factor receptor (EGFR, a well-known cell proliferation-stimulating molecule in tumorigenesis) and p-EGFR in tumor tissues were determined by western blot. A carbon particle clearance test, measurement of serum cytokine levels, a splenic T lymphocyte proliferation test, and T lymphocyte subpopulation analysis were used to evaluate the effect of eckol on the immune function of tumor-bearing mice. Moreover, CD11c+-dendritic cell (DC) infiltration in tumor tissues was detected by immunohistochemistry, and the surface molecules on bone marrow-derived DCs were analyzed using flow cytometry. The pro-apoptosis and anti-proliferation activities of eckol were manifested by the increased TUNEL-positive apoptotic cells, the upregulated Caspase-3 and Caspase-9 expression, and the downregulated expression of Bcl-2, Bax, EGFR and p-EGFR in eckol-treated transplanted S180 tumors. Most importantly, eckol stimulated the mononuclear phagocytic system, recruited and activated DCs, promoted the tumor-specific Th1 responses, increased the CD4+/CD8+ T lymphocyte ratio, and enhanced cytotoxic T lymphocyte responses in the eckol-treated animals, suggesting its potent stimulatory property on innate and adaptive immune responses. This study suggested that eckol might act as a functional food constituent derived from marine brown algae with a potential in vivo anti-tumor effect achieved by improving the immune response.

5.
Math Biosci Eng ; 16(3): 1190-1209, 2019 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-30947415

RESUMO

Particle swarm optimizer was proposed in 1995, and since then, it has become an extremely popular swarm intelligent algorithm with widespread applications. Many modified versions of it have been developed, in which, comprehensive learning particle swarm optimizer is a very powerful one. In order to enhance its performance further, a local search based on Latin hypercube sampling is combined with it in this work. Due to that a hypercube should become smaller and smaller for better local search ability during the search process, a control method is designed to set the size of the hypercube. Via numerical experiments, it can be observed that the comprehensive learning particle swarm optimizer with the local search based on Latin hypercube sampling has a strong ability on both global and local search. The hybrid algorithm is applied in cylindricity error evaluation problem and it outperforms several other algorithms.


Assuntos
Simulação por Computador , Aprendizado de Máquina , Algoritmos , Modelos Teóricos , Reconhecimento Automatizado de Padrão/métodos , Reprodutibilidade dos Testes , Software
6.
Biomed Pharmacother ; 109: 2145-2154, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30551472

RESUMO

Although dietary flavonoid quercetin alleviates diabetes-associated cognitive decline in rodents, the mechanisms are not clearly clarified. This study was designed to investigate whether quercetin showed neuroprotection on central neurons against chronic high glucose through the enhancement of Nrf2/ARE/glyoxalase 1 (Glo-1) pathway. SH-SY5Y cells were divided into 8 groups: normal glucose, high glucose (HG), osmotic pressure control, solvent control, HG plus low, middle, high concentrations of quercetin, or Nrf2 activator (sulforaphane). After treatment for 72 h, the associated parameters were measured. We found quercetin and sulforaphane increased cell viability, and enhanced Glo-1 functions (Glo-1 activity, the reduced glutathione and advanced glycation end-products levels) as well as Glo-1 protein and mRNA levels in SH-SY5Y cells cultured with HG. Meanwhile, quercetin and sulforaphane activated Nrf2/ARE pathway, reflected by the raised Nrf2 and p-Nrf2 levels, and the elevated protein and mRNA levels of γ-glutamycysteine synthase (γ-GCS), a known target gene of Nrf2/ARE signaling. Moreover, Nrf2/ARE pathway was activated after pretreatment with a PKC activator, p38 MAPK inhibitor, or GSK-3ß inhibitor under the condition of HG, and quercetin addition further strengthened this pathway; however, PKC inhibition or GSK-3ß activation pretreatment reversed the effects of quercetin on the protein expression of γ-GCS in the HG condition. In summary, quercetin exerts the neuroprotection by enhancing Glo-1 functions in central neurons under chronic HG condition, which may be mediated by activation of Nrf2/ARE pathway; furthermore, the increased Nrf2 phosphorylation mediated by PKC activation and/or GSK-3ß inhibition may involve in the activation of Nrf2/ARE pathway.


Assuntos
Hidrolases de Éster Carboxílico/metabolismo , Glucose/toxicidade , Lactoilglutationa Liase/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Neuroproteção/efeitos dos fármacos , Quercetina/farmacologia , Antioxidantes/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Relação Dose-Resposta a Droga , Humanos , Fator 2 Relacionado a NF-E2/agonistas , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neuroproteção/fisiologia , Fosforilação/efeitos dos fármacos , Fosforilação/fisiologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia
7.
Artigo em Inglês | MEDLINE | ID: mdl-30251823

RESUMO

Black phosphorus (BP) nanosheets with unique biocompatibility and superior optical performance have attracted enormous attention in material science. However, their instability and poor solution-processability severely limit their clinical applications. In this work, we demonstrate the use of silk fibroin (SF) as an exfoliating agent to produce thin-layer BP nanosheets with long-term stability and facile solution-processability. Presence of SF prevents rapid oxidation and degradation of the resultant BP nanosheets, enhancing their performance in physiological environment. The SF-modified BP nanosheets exhibit subtle solution-processability and are fabricated into various BP-based material formats. As superior photothermal agents, BP-based wound dressings effectively prevent bacterial infection and promote wound repair. Therefore, this work opens new avenues for unlocking current challenges of BP nanosheet applications for practical biomedical purposes.

8.
Clin Breast Cancer ; 18(5): e985-e995, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29983379

RESUMO

BACKGROUND: Contrast-enhanced spectral mammography (CESM) is a new image examination technology that has developed over the past few years. As CESM technology keeps improving, a current meta-analysis review is needed to systematically evaluate the potential diagnostic value of CESM. METHODS: A total of 18 studies were included in the review. Sensitivity, specificity, and other important parameters of CESM accuracy for breast cancer diagnosis were pooled and analyzed using random-effects models. Summary receiver operating characteristic curves were calculated for overall accuracy estimation. RESULTS: The summary estimates for CESM in the diagnosis of breast cancer were as follows: the pooled sensitivity and specificity were 0.89 (95% confidence interval [CI], 0.88-0.91) and 0.84 (95% CI, 0.82-0.85), respectively. Positive likelihood ratio was 3.73 (95% CI, 2.68-5.20), negative likelihood ratio was 0.10 (95% CI, 0.06-0.15), and diagnostic odds ratio was 71.36 (95% CI, 36.28-140.39). The area under the curve was 0.96 (standard error = 0.011). CONCLUSION: CESM has a high diagnostic accuracy for evaluating breast cancer and can be considered as a useful test for initial assessment of breast lesions.

9.
Phytother Res ; 32(8): 1574-1582, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29682805

RESUMO

Rhizome of Anemarrhena asphodeloides Bunge (AA, family Liliaceae) has been widely used in China for thousands of years to treat febrile diseases and diabetes. Steroidal saponins from AA show good antidiabetes effects and ameliorate diabetic complications. This study was designed to investigate the effects of sarsasapogenin (Sar), a major sapogenin from AA, on diabetic nephropathy (DN) in rats, and to explore the possible mechanisms. Diabetic rats were divided into 3 groups treated orally with Sar (0, 20, or 60 mg/kg) and carboxymethylcellulose sodium, whereas normal rats for Sar (0 or 60 mg/kg) and carboxymethylcellulose sodium. We found that chronic treatment with Sar for 9 weeks significantly ameliorated renal dysfunction of diabetic rats, as evidenced by decreases in albuminuria, kidney weight index, serum uric acid, and morphologic changes such as extracellular matrix expansion and accumulation (fibronectin and collagen IV levels, etc.). Meanwhile, Sar treatment resulted in decreases in interleukin-18, NLRP3, and activated caspase 1 levels as well as advanced glycation endproducts (AGEs) and their receptor (RAGE) levels in the renal cortex of diabetic rats. However, Sar has no effects on the above indices in the normal rats. Therefore, Sar can markedly ameliorate diabetic nephropathy in rats via inhibition of NLRP3 inflammasome activation and AGEs-RAGE interaction.


Assuntos
Nefropatias Diabéticas/tratamento farmacológico , Espirostanos/farmacologia , Anemarrhena/química , Animais , China , Diabetes Mellitus Experimental/complicações , Medicamentos de Ervas Chinesas/farmacologia , Produtos Finais de Glicação Avançada , Interleucina-18/metabolismo , Rim/efeitos dos fármacos , Masculino , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Ratos , Ratos Sprague-Dawley , Rizoma/química , Saponinas/farmacologia , Ácido Úrico/sangue
10.
Chemosphere ; 194: 450-462, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29227893

RESUMO

Implementing "targeted" eco-pharmacovigilance(EPV) which focuses on individual or specific pharmaceuticals on a prioritised basis is a feasible, economical and customized approach to reduce the environmental concentrations and risks of pharmaceuticals. Non-steroidal anti-inflammatory drugs(NSAIDs) remaining in environment are a kind of priority hazard substances, due to a notable case that diclofenac residues caused the loss of more than 99% of vultures across the Indian sub-continent. Ketoprofen, as another widely used NSAID with comparable or even higher global consumption than diclofenac, in the environment has been shown to present a potential risk to non-target terrestrial and aquatic species. Based on the review of 85 articles reporting the analyses of ketoprofen residues in environment since 2010, we found that this NSAID frequently present in various environmental compartments around the world. Therefore, it is urgent to implement EPV targeting ketoprofen pollution. Here, we provide some recommendations for implementing the targeted EPV for ketoprofen, including: Closely monitoring ketoprofen in the natural environment; Reducing the residues of ketoprofen through source control; Encouraging urine source separation and treatment; Limiting the application of veterinary ketoprofen; Designing and constituting a framework system of targeted EPV. But some challenges, such as ambiguity in the accountability of the main bodies responsible for continued monitoring of ketoprofen residues, the lack of optimized urine source separation scenarios and procedure, the need for detailed design and application schemes of the framework system of targeted EPV, etc. should be addressed.


Assuntos
Anti-Inflamatórios não Esteroides/análise , Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Cetoprofeno/análise , Farmacovigilância , Anti-Inflamatórios não Esteroides/toxicidade , Poluentes Ambientais/toxicidade , Cetoprofeno/toxicidade
11.
Naunyn Schmiedebergs Arch Pharmacol ; 391(2): 159-168, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29275517

RESUMO

The aim of this study is to investigate effects and potential mechanisms of sarsasapogenin (Sar), an active component purified from Rhizoma Anemarrhenae, on high glucose-induced amyloid-beta (Aß) peptide overproduction in HT-22 cells. HT-22 cells were divided into normal glucose; high glucose (HG); HG co-treated with low, middle, and high concentration of Sar (1, 5, 25 µmol/L); and peroxisome proliferator-activated receptor γ (PPARγ) agonist (10 µmol/L pioglitazone). After treatment for 24 h, protein expression of Aß and ß-site Aß precursor protein cleaving enzyme 1 (BACE1) and activated PPARγ level were determined by Western blot; Aß42 levels were also measured by using both immunofluorescence and ELISA methods. BACE1 activity and mRNA level were assessed by fluorospectrophotometry and quantitative PCR, respectively. Cell viability was assayed with a CCK-8 kit. Elevated Aß expression and Aß42 level were found in HG-treated HT-22 cells, accompanied by increased BACE1 protein and mRNA levels as well as enzymatic activity, which was markedly attenuated by three concentrations of Sar and pioglitazone. Moreover, HG reduced nuclear PPARγ levels, which was reversed by middle and high concentrations of Sar as well as pioglitazone. PPARγ antagonist GW9662 (20 µmol/L) pretreatment reversed the effect of Sar on BACE1 protein expression in HG-cultured HT-22 cells. Additionally, Sar suppressed HG-induced decreases in cell viability of HT-22 cells. High glucose can induce an increase in Aß levels and a decrease in cell viability in HT-22 cells, while co-treatment with Sar improves these results, which is mediated likely through activation of PPARγ and subsequent downregulation of BACE1.


Assuntos
Peptídeos beta-Amiloides/antagonistas & inibidores , Peptídeos beta-Amiloides/biossíntese , Medicamentos de Ervas Chinesas/farmacologia , Glucose/toxicidade , Fragmentos de Peptídeos/antagonistas & inibidores , Fragmentos de Peptídeos/biossíntese , Espirostanos/farmacologia , Animais , Linhagem Celular Transformada , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Camundongos
12.
Cell Cycle ; 12(7): 1119-27, 2013 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-23466707

RESUMO

In previous studies from other labs it has been well demonstrated that the ectopic expression of c-Myc in mammary epithelial cells can induce epithelial-mesenchymal transition (EMT), whereas in our pilot experiment, epithelial-like morphological changes were unexpectedly observed in c-Myc-expressing pig fibroblasts [i.e., porcine embryonic fibroblasts (PEFs) and porcine dermal fibroblasts (PDFs)] and pig mesenchymal stem cells, suggesting that the same c-Myc gene is entitled to trigger EMT in epithelial cells and mesenchymal-epithelial transition (MET) in fibroblasts. This prompted us to characterize the existence of a MET in c-Myc-expressing PEFs and PDFs at the molecular level. qRT-PCR, immunofluorescence and western blot analysis illustrated that epithelial-like morphological changes were accompanied by the increased expression of epithelial markers [such as cell adhesion proteins (E-cadherin, α-catenin and Bves), tight junction protein occludin and cytokeratins (Krt8 and Krt18)], the reduced expression of mesenchymal markers [vimentin, fibronectin 1 (FN1), snail1, collagen family of proteins (COL1A1, COL5A2) and matrix metalloproteinase (MMP) family (MMP12 and MMP14)] and the decreased cell motility and increased cell adhesion in c-Myc-expressing PEFs and PDFs. Furthermore, the ectopic expression of c-Myc in pig fibroblasts disrupted the stress fiber network, suppressed the formation of filopodia and lamellipodia, and resulted in RhoA/Rock pathway inactivation, which finally participates in epithelial-like morphological conversion. Taken together, these findings demonstrate, for the first time, that the enforced expression of c-Myc in fibroblasts can trigger MET, to which cytoskeleton depolymerization and RhoA/Rock pathway inactivation contribute.


Assuntos
Actinas/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Quinases Associadas a rho/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismo , Animais , Adesão Celular , Movimento Celular , Células Cultivadas , Derme/citologia , Transição Epitelial-Mesenquimal , Fibroblastos/citologia , Fibroblastos/metabolismo , Células HEK293 , Humanos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , RNA Mensageiro/metabolismo , Suínos , Transfecção
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA