Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 30
Filtrar
1.
Comput Biol Med ; 169: 107898, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38176210

RESUMO

Accurate segmentation of the thyroid gland in ultrasound images is an essential initial step in distinguishing between benign and malignant nodules, thus facilitating early diagnosis. Most existing deep learning-based methods to segment thyroid nodules are learned from only a single view or two views, which limits the performance of segmenting nodules at different scales in complex ultrasound scanning environments. To address this limitation, this study proposes a multi-view learning model, abbreviated as MLMSeg. First, a deep convolutional neural network is introduced to encode the features of the local view. Second, a multi-channel transformer module is designed to capture long-range dependency correlations of global view between different nodules. Third, there are semantic relationships of structural view between features of different layers. For example, low-level features and high-level features are endowed with hidden relationships in the feature space. To this end, a cross-layer graph convolutional module is proposed to adaptively learn the correlations of high-level and low-level features by constructing graphs across different layers. In addition, in the view fusion, a channel-aware graph attention block is devised to fuse the features from the aforementioned views for accurate segmentation of thyroid nodules. To demonstrate the effectiveness of the proposed method, extensive comparative experiments were conducted with 14 baseline methods. MLMSeg achieved higher Dice coefficients (92.10% and 83.84%) and Intersection over Union scores (86.60% and 73.52%) on two different thyroid datasets. The exceptional segmentation capability of MLMSeg for thyroid nodules can greatly assist in localizing thyroid nodules and facilitating more precise measurements of their transverse and longitudinal diameters, which is of significant clinical relevance for the diagnosis of thyroid nodules.


Assuntos
Nódulo da Glândula Tireoide , Humanos , Ultrassonografia , Redes Neurais de Computação , Semântica , Processamento de Imagem Assistida por Computador
2.
Artigo em Inglês | MEDLINE | ID: mdl-37224361

RESUMO

The construction of undetectable adversarial examples with few perturbances remains a difficult problem in adversarial attacks. At present, most solutions use the standard gradient optimization algorithm to build adversarial examples by applying global perturbations to benign samples and then launch attacks on the targets (e.g., face recognition systems). However, when the perturbance size is limited, the performance of these approaches suffers substantially. The content of crucial places in an image, on the other hand, will impact the final prediction; if these areas can be investigated and limited perturbances introduced, an acceptable adversarial example will be constructed. Based on the foregoing research, this article offers a dual attention adversarial network (DAAN) to produce adversarial examples with limited perturbations. DAAN initially searches for effective areas in an input image using the spatial attention network and channel attention network, and then creates space and channel weights. Following that, these weights direct an encoder and a decoder to generate effective perturbation, which is then combined with the input to produce an adversarial example. Finally, the discriminator determines if the created adversarial examples are true or false, and the attacked model is utilized to determine whether the generated samples fit the attack targets. Extensive studies on various datasets show that DAAN not only delivers the best attack performance across all comparison algorithms with few perturbations, but it can also significantly improve the defensiveness of the attacked models.

3.
Artigo em Inglês | MEDLINE | ID: mdl-37015581

RESUMO

In prenatal examinations, the fetal head circumference (HC) measurement is essential for assessing fetal weight and health conditions. The sonographers obtain the fetal HC manually by fitting peripheral skull ellipse in clinical practice, which is highly subjective, time-consuming, and experience-dependent. Recently, many fetal HC automatic measurement algorithms have been proposed to improve workflow efficiency in prenatal examination. But most automatic measurement algorithms focus on using fetal head segmentation as an intermediate processing step, and HC estimation relies heavily on segmentation results, which causes the accumulation of errors in the above two stages. Independent of the segmentation method, we design a regression network to generate the oriented bounding box to detect the head contour, and directly obtain the fetal head parameters with a pixel-based ellipse regression (PER) loss. Moreover, an effective 3D attention mechanism is integrated into the network to estimate HC more precisely without adding parameters in complex ultrasound images. The extensive experimental results on the public HC18 and our clinical dataset show that the proposed network provides a feasible scheme for end-to-end estimating fetal HC, and avoids the mistake brought by the intermediary processes.

4.
RSC Adv ; 11(18): 10996-11003, 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-35423576

RESUMO

A new noble metal-free Ni-Co-P/HAP (hydroxyapatite) amorphous alloy catalyst was synthesized by an impregnation-chemical reduction method; the structure and properties of the catalysts were characterized by XRD, SEM, BET, XPS and DSC. Based on the model of the hydrodeoxygenation (HDO) of vanillin to 2-methoxy-4-methylphenol (MMP) with formic acid as a hydrogen source, the catalytic performance of the catalyst was studied. The results found that the Ni-Co-P/HAP catalyst exhibited excellent catalytic activity for the in situ HDO reaction of vanillin compared with Ni-P and Ni-Co-P. The conversion of vanillin could be high to 97.86% with MMP selectivity of 93.97% under optimized reaction conditions. In addition, mechanism studies have shown that the side reaction of carbocation and vanillyl alcohol (HMP) condensation can be effectively reduced with increasing the hydrogenation rate, thereby the selectivity of MMP was effectively increased.

5.
IEEE Trans Neural Netw Learn Syst ; 30(11): 3360-3369, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30716052

RESUMO

Zeroing neural network (ZNN), as a powerful calculating tool, is extensively applied in various computation and optimization fields. Convergence and noise-tolerance performance are always pursued and investigated in the ZNN field. Up to now, there are no unified ZNN models that simultaneously achieve the finite-time convergence and inherent noise tolerance for computing time-varying quadratic optimization problems, although this superior property is highly demanded in practical applications. In this paper, for computing time-varying quadratic optimization within finite-time convergence in the presence of various additive noises, a new framework for ZNN is designed to fill this gap in a unified manner. Specifically, different from the previous design formulas either possessing finite-time convergence or possessing noise-tolerance performance, a new design formula with finite-time convergence and noise tolerance is proposed in a unified framework (and thus called unified design formula). Then, on the basis of the unified design formula, a unified ZNN (UZNN) is, thus, proposed and investigated in the unified framework of ZNN for computing time-varying quadratic optimization problems in the presence of various additive noises. In addition, theoretical analyses of the unified design formula and the UZNN model are given to guarantee the finite-time convergence and inherent noise tolerance. Computer simulation results verify the superior property of the UZNN model for computing time-varying quadratic optimization problems, as compared with the previously proposed ZNN models.

6.
IEEE Trans Neural Netw Learn Syst ; 29(6): 2337-2351, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-28436893

RESUMO

As data sets become larger and more complicated, an extreme learning machine (ELM) that runs in a traditional serial environment cannot realize its ability to be fast and effective. Although a parallel ELM (PELM) based on MapReduce to process large-scale data shows more efficient learning speed than identical ELM algorithms in a serial environment, some operations, such as intermediate results stored on disks and multiple copies for each task, are indispensable, and these operations create a large amount of extra overhead and degrade the learning speed and efficiency of the PELMs. In this paper, an efficient ELM based on the Spark framework (SELM), which includes three parallel subalgorithms, is proposed for big data classification. By partitioning the corresponding data sets reasonably, the hidden layer output matrix calculation algorithm, matrix decomposition algorithm, and matrix decomposition algorithm perform most of the computations locally. At the same time, they retain the intermediate results in distributed memory and cache the diagonal matrix as broadcast variables instead of several copies for each task to reduce a large amount of the costs, and these actions strengthen the learning ability of the SELM. Finally, we implement our SELM algorithm to classify large data sets. Extensive experiments have been conducted to validate the effectiveness of the proposed algorithms. As shown, our SELM achieves an speedup on a cluster with ten nodes, and reaches a speedup with 15 nodes, an speedup with 20 nodes, a speedup with 25 nodes, a speedup with 30 nodes, and a speedup with 35 nodes.

7.
Biomed Res Int ; 2014: 793879, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24995328

RESUMO

To improve the bioavailability of orally administered lipophilic coenzyme Q10 (CoQ10), we formulated a novel lipid-free nano-CoQ10 system stabilized by various surfactants. Nano-CoQ10s, composed of 2.5% (w/w) CoQ10, 1.67% (w/w) surfactant, and 41.67% (w/w) glycerol, were prepared by hot high-pressure homogenization. The resulting formulations were characterized by particle size, zeta potential, differential scanning calorimetry, and cryogenic transmission electron microscopy. We found that the mean particle size of all nano-CoQ10s ranged from 66.3 ± 1.5 nm to 92.7 ± 1.5 nm and the zeta potential ranged from -12.8 ± 1.4 mV to -41.6 ± 1.4 mV. The CoQ10 in nano-CoQ10s likely existed in a supercooled state, and nano-CoQ10s stored in a brown sealed bottle were stable for 180 days at 25 °C. The bioavailability of CoQ10 was evaluated following oral administration of CoQ10 formulations in Sprague-Dawley rats. Compared to the values observed following administration of CoQ10-Suspension, nano-CoQ10 modified with various surfactants significantly increased the maximum plasma concentration and the area under the plasma concentration-time curve. Thus, the lipid-free system of a nano-CoQ10 stabilized with a surfactant may be an effective vehicle for improving oral bioavailability of CoQ10.


Assuntos
Disponibilidade Biológica , Sistemas de Liberação de Medicamentos , Ubiquinona/análogos & derivados , Administração Oral , Animais , Humanos , Nanopartículas/administração & dosagem , Nanopartículas/química , Ratos , Ratos Sprague-Dawley , Solubilidade , Ubiquinona/administração & dosagem , Ubiquinona/química
8.
J Wildl Dis ; 50(1): 109-12, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24171575

RESUMO

We investigated an outbreak of acute pneumonia among adult Chinese hares (Lepus sinensis) and diarrhea among juvenile hares in Hebei Province, China, in 2012. Diagnosis was based on necropsy examination, microbial characteristics, biochemical identification, and nucleotide sequence analysis. The isolated bacteria from tissue samples of dead hares were identified as Klebsiella pneumoniae ssp. pneumoniae (K. pneumoniae). This K. pneumoniae was resistant to the antimicrobials imipenem, meropenem, penicillin, and vancomycin, but was highly sensitive to cefepime, cotrimoxazole, and enrofloxacin. Klebsiella pneumoniae is an important opportunistic pathogen, which often causes nosocomial infections in immunocompromised patients. However, the emergence of drug-resistant K. pneumoniae in hares indicates the existence of increasing risk of pathogen transmission between humans and wildlife. Given the close association between wildlife, livestock, and humans, it is important to identify epidemiologic factors associated with infection in these hares to minimize the risk of K. pneumoniae transmission.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla , Lebres/microbiologia , Infecções por Klebsiella/veterinária , Klebsiella pneumoniae/efeitos dos fármacos , Animais , China , Contagem de Colônia Microbiana/veterinária , Infecção Hospitalar , Reservatórios de Doenças/microbiologia , Reservatórios de Doenças/veterinária , Relação Dose-Resposta a Droga , Humanos , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/transmissão , Klebsiella pneumoniae/isolamento & purificação , Testes de Sensibilidade Microbiana/veterinária , Saúde Pública
9.
J Nanosci Nanotechnol ; 13(1): 706-10, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23646802

RESUMO

Coenzyme Q10-loaded lecithin nanocapsules (CoQ10-LNCs), composed of a CoQ10/lecithin/ GTCC/glycerol aqueous solution, were prepared by high-pressure homogenization. The zeta potential of the CoQ10-LNCs above -60 mV was determined on a Malvern Zetasize 2000 (Malvern Instruments, UK). The spherical shape of the CoQ10-LNCs was observed by using freeze-fracture transmission electron microscopy (FF-TEM), and the particle size was found to be below 100 nm. The supercooled state of the CoQ10-LNCs was observed by differential scanning calorimetry (DSC). In an oral bioavailability study, the CoQ10 plasma level after administering CoQ10-LNCs was higher than that after administering a CoQ10 tablet over 24 hours, and the relative bioavailability of CoQ10 was improved to 176.6% in mice. Based on the above results, the LNC delivery system might be a potential vehicle for improving the oral bioavailability of CoQ10.


Assuntos
Lecitinas/química , Boca/metabolismo , Nanocápsulas/administração & dosagem , Nanocápsulas/química , Ubiquinona/análogos & derivados , Animais , Disponibilidade Biológica , Teste de Materiais , Camundongos , Ubiquinona/administração & dosagem , Ubiquinona/química , Ubiquinona/farmacocinética
10.
PLoS One ; 8(2): e56201, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23418535

RESUMO

The 2009 influenza pandemic had a tremendous social and economic impact. To study the genetic diversity and evolution of the 2009 H1N1 virus, a mutation network for the non-structural (NS) gene of the virus was constructed. Strains of the 2009 H1N1 pandemic influenza A virus could be divided into two categories based on the V123I mutation in the NS1 gene: G1 (characterized as 123 Val) and G2 (characterized as 123 Ile). Sequence homology analysis indicated that one type of NS sequence, primarily isolated from Mexico, was likely the original type in this pandemic. The two genotypes of the virus presented distinctive clustering features in their geographic distributions. These results provide additional insight into the genetics and evolution of human pandemic influenza H1N1.


Assuntos
Evolução Molecular , Vírus da Influenza A Subtipo H1N1/genética , Mutação , Proteínas não Estruturais Virais/genética , Frequência do Gene , Redes Reguladoras de Genes , Variação Genética , Genótipo , Geografia , Humanos , Vírus da Influenza A Subtipo H1N1/classificação , Influenza Humana/epidemiologia , Influenza Humana/virologia , Modelos Genéticos , Pandemias , Filogenia , Seleção Genética , Especificidade da Espécie , Proteínas não Estruturais Virais/classificação
11.
PLoS One ; 6(9): e25808, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21980538

RESUMO

H9N2 influenza A viruses have become endemic in different types of terrestrial poultry and wild birds in Asia, and are occasionally transmitted to humans and pigs. To evaluate the role of black-billed magpies (Pica pica) in the evolution of influenza A virus, we conducted two epidemic surveys on avian influenza viruses in wild black-billed magpies in Guangxi, China in 2005 and characterized three isolated black-billed magpie H9N2 viruses (BbM viruses). Phylogenetic analysis indicated that three BbM viruses were almost identical with 99.7 to 100% nucleotide homology in their whole genomes, and were reassortants containing BJ94-like (Ck/BJ/1/94) HA, NA, M, and NS genes, SH/F/98-like (Ck/SH/F/98) PB2, PA, and NP genes, and H5N1-like (Ck/YN/1252/03, clade 1) PB1 genes. Genetic analysis showed that BbM viruses were most likely the result of multiple reassortments between co-circulating H9N2-like and H5N1-like viruses, and were genetically different from other H9N2 viruses because of the existence of H5N1-like PB1 genes. Genotypical analysis revealed that BbM viruses evolved from diverse sources and belonged to a novel genotype (B46) discovered in our recent study. Molecular analysis suggested that BbM viruses were likely low pathogenic reassortants. However, results of our pathogenicity study demonstrated that BbM viruses replicated efficiently in chickens and a mammalian mouse model but were not lethal for infected chickens and mice. Antigenic analysis showed that BbM viruses were antigenic heterologous with the H9N2 vaccine strain. Our study is probably the first report to document and characterize H9N2 influenza viruses isolated from black-billed magpies in southern China. Our results suggest that black-billed magpies were susceptible to H9N2 influenza viruses, which raise concerns over possible transmissions of reassortant H9N2 viruses among poultry and wild birds.


Assuntos
Virus da Influenza A Subtipo H5N1/genética , Vírus da Influenza A Subtipo H9N2/genética , Vírus da Influenza A Subtipo H9N2/isolamento & purificação , Passeriformes/virologia , Vírus Reordenados/genética , Vírus Reordenados/isolamento & purificação , Proteínas Virais/genética , Animais , Galinhas/virologia , China , Epidemias , Evolução Molecular , Feminino , Genótipo , Humanos , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Virus da Influenza A Subtipo H5N1/patogenicidade , Virus da Influenza A Subtipo H5N1/fisiologia , Vírus da Influenza A Subtipo H9N2/patogenicidade , Vírus da Influenza A Subtipo H9N2/fisiologia , Camundongos , Filogenia , Vírus Reordenados/patogenicidade , Vírus Reordenados/fisiologia , Análise de Sequência , Replicação Viral
12.
Int J Pharm ; 420(1): 172-9, 2011 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-21888960

RESUMO

rhPTH1-34 is clinically used for osteoporosis treatment. However, this peptide drug has no oral bioavailability because of proteolysis and low membrane permeability in gastrointestinal gut. This study explored the possibility of absorption enhancement for rhPTH1-34 through the oral delivery of the microemulsion. The microemulsion (85:15, oil/water) consisting of Labrasol, Crodamol GTCC, Solutol HS 15, d-α-tocopheryl acetate (6:2:1:1, w/w) and saline water was developed and characterized, including particle size, morphology, drug loading efficiency and permeability, stability and pharmacokinetics. The microemulsion showed high drug loading efficiency (83%) and permeability, and significantly higher resistance to proteolysis in vitro study. The relative oral bioavailability was 5.4% and 12.0% when delivered to gastric and ileum. Besides, osteoporosis rats were induced and treated with oral rhPTH1-34 microemulsion (0.05 mg/kg), injection (0.01 mg/kg) and vehicle, respectively, for 8 weeks. The proximal tibia bone mineral content and density in oral rats (0.188 ± 0.008 g, 0.283 ± 0.014 g/cm(2)) was significantly increased compared to the control rats (0.169 ± 0.006 g, 0.266 ± 0.011 g/cm(2)), reaching to the sham rats. And the proximal tibia microstructure of oral rats was improved greatly, approaching sham level too. These findings revealed that oral microemulsion may represent an effective oral delivery system for rhPTH1-34.


Assuntos
Conservadores da Densidade Óssea/administração & dosagem , Portadores de Fármacos , Teriparatida/administração & dosagem , Administração Oral , Animais , Disponibilidade Biológica , Densidade Óssea/efeitos dos fármacos , Conservadores da Densidade Óssea/química , Células CACO-2 , Química Farmacêutica , Modelos Animais de Doenças , Composição de Medicamentos , Estabilidade de Medicamentos , Emulsões , Feminino , Mucosa Gástrica/metabolismo , Humanos , Íleo/metabolismo , Absorção Intestinal , Masculino , Nanotecnologia , Osteoporose/tratamento farmacológico , Osteoporose/patologia , Ovariectomia , Tamanho da Partícula , Peptídeo Hidrolases/metabolismo , Permeabilidade , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes/administração & dosagem , Solubilidade , Tecnologia Farmacêutica/métodos , Teriparatida/química , Tíbia/efeitos dos fármacos , Tíbia/patologia
13.
PLoS One ; 6(2): e17212, 2011 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-21386964

RESUMO

H9N2 influenza A viruses have become established worldwide in terrestrial poultry and wild birds, and are occasionally transmitted to mammals including humans and pigs. To comprehensively elucidate the genetic and evolutionary characteristics of H9N2 influenza viruses, we performed a large-scale sequence analysis of 571 viral genomes from the NCBI Influenza Virus Resource Database, representing the spectrum of H9N2 influenza viruses isolated from 1966 to 2009. Our study provides a panoramic framework for better understanding the genesis and evolution of H9N2 influenza viruses, and for describing the history of H9N2 viruses circulating in diverse hosts. Panorama phylogenetic analysis of the eight viral gene segments revealed the complexity and diversity of H9N2 influenza viruses. The 571 H9N2 viral genomes were classified into 74 separate lineages, which had marked host and geographical differences in phylogeny. Panorama genotypical analysis also revealed that H9N2 viruses include at least 98 genotypes, which were further divided according to their HA lineages into seven series (A-G). Phylogenetic analysis of the internal genes showed that H9N2 viruses are closely related to H3, H4, H5, H7, H10, and H14 subtype influenza viruses. Our results indicate that H9N2 viruses have undergone extensive reassortments to generate multiple reassortants and genotypes, suggesting that the continued circulation of multiple genotypical H9N2 viruses throughout the world in diverse hosts has the potential to cause future influenza outbreaks in poultry and epidemics in humans. We propose a nomenclature system for identifying and unifying all lineages and genotypes of H9N2 influenza viruses in order to facilitate international communication on the evolution, ecology and epidemiology of H9N2 influenza viruses.


Assuntos
Variação Genética , Genoma Viral , Vírus da Influenza A Subtipo H9N2/genética , Filogenia , Análise de Sequência de DNA , Animais , Sequência de Bases , Doenças das Aves/virologia , Aves/virologia , Variação Genética/fisiologia , Genótipo , Interações Hospedeiro-Patógeno/genética , Humanos , Vírus da Influenza A Subtipo H9N2/classificação , Influenza Aviária/transmissão , Influenza Aviária/virologia , Influenza Humana/transmissão , Influenza Humana/virologia , Dados de Sequência Molecular , Doenças das Aves Domésticas/virologia
14.
J Integr Plant Biol ; 53(5): 347-57, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21348939

RESUMO

Plant annexins represent a multigene family involved in cellular elongation and development. A cDNA encoding a novel annexin was isolated from a cotton (Gossypium hirsutum) fiber cDNA library and designated GhAnx1. This gene encodes a 316 amino acid protein with a theoretical molecular mass of 36.06 kDa and a theoretical pI of 6.19. At the amino acid level, it shares high sequence similarity and has evolutionary relationships with annexins from higher plants. The purified recombinant protein expressed in Escherichia coli was used to investigate its physicochemical properties. Circular dichroism spectrum analyses showed a positive peak rising to the maximum at 196 nm and a broad negative band rounding 215 nm, suggesting that the GhAnx1 protein was prominently α-helical. The fluorescence measurements indicated that it could bind to Ca(2+) in vitro. These results demonstrated that GhAnx1 was a typical annexin protein in cotton. A bioassay experiment was conducted to analyze its potential function and showed that E. coli cells expressing GhAnx1 were protected from tert-butyl hydroperoxide (tBH) stress, suggesting that it had a potential antioxidative role. Northern blot analyses revealed that GhAnx1 was highly expressed in fibers, especially during the elongation stage, suggesting that it might be important for fiber elongation.


Assuntos
Anexinas/genética , Gossypium/genética , Proteínas de Plantas/genética , Sequência de Aminoácidos , Anexinas/metabolismo , Antioxidantes/metabolismo , Northern Blotting , Expressão Gênica , Gossypium/metabolismo , Dados de Sequência Molecular , Proteínas de Plantas/isolamento & purificação , Proteínas de Plantas/metabolismo , Proteínas Recombinantes/isolamento & purificação , Análise de Sequência de DNA
15.
Nanoscale Res Lett ; 5(10): 1561-9, 2010 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-21076708

RESUMO

The purpose of this study was to investigate the influence of the inner lipid ratio on the physicochemical properties and skin targeting of surfactant-free lecithin-based coenzyme Q10-loaded lipid nanocapsules (CoQ10-LNCs). The smaller particle size of CoQ10-LNCs was achieved by high pressure and a lower ratio of CoQ10/GTCC (Caprylic/capric triglyceride); however, the zeta potential of CoQ10-LNCs was above /- 60 mV/ with no distinct difference among them at different ratios of CoQ10/GTCC. Both the crystallisation point and the index decreased with the decreasing ratio of CoQ10/GTCC and smaller particle size; interestingly, the supercooled state of CoQ10-LNCs was observed at particle size below about 200 nm, as verified by differential scanning calorimetry (DSC) in one heating-cooling cycle. The lecithin monolayer sphere structure of CoQ10-LNCs was investigated by cryogenic transmission electron microscopy (Cryo-TEM). The skin penetration results revealed that the distribution of Nile red-loaded CoQ10-LNCs depended on the ratio of inner CoQ10/GTCC; moreover, epidermal targeting and superficial dermal targeting were achieved by the CoQ10-LNCs application. The highest fluorescence response was observed at a ratio of inner CoQ10/GTCC of 1:1. These observations suggest that lecithin-based LNCs could be used as a promising topical delivery vehicle for lipophilic compounds.

16.
Vaccine ; 29(2): 323-8, 2010 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-21029808

RESUMO

The aim of this work was to evaluate efficiency as well as the type of immune response, Th1 or Th2, induced by multivalent DNA vaccinations in C57BL/6 interleukin-12p40 (IL-12p40) knockout (KO) mice. A recombinant pVAX-15-23 plasmid DNA was constructed by inserting surface glycoprotein (cp15- and p23)-encoding DNA into the pVAX1 expression vector. Various parameters including antibody and cytokine responses, proliferation assay and oocyst shedding were used to evaluate the type of immune response and the level of protection against challenge infection. Obtained results indicated that plasmid pVAX-15-23 induced strong protective immune response against C. parvum characterized by dominance of IgG2a, high level of INF-γ and lower level of the oocysts shedding after challenge infection. Moreover, co-immunization with the multivalent DNA and pMEM12R plasmid encoding IL-12 can further enhance these responses compared with the multivalent DNA alone. The obtained results suggest that multivalent pVAX-15-23 DNA vaccine may be a candidate as a generic approach to C. parvum immunization applicable to clinical practice.


Assuntos
Criptosporidiose/prevenção & controle , Cryptosporidium parvum/imunologia , Vacinas Protozoárias/imunologia , Vacinas de DNA/imunologia , Adjuvantes Imunológicos/administração & dosagem , Animais , Anticorpos Antiprotozoários/sangue , Criptosporidiose/imunologia , Cryptosporidium parvum/genética , Feminino , Expressão Gênica , Vetores Genéticos , Glicoproteínas/genética , Glicoproteínas/imunologia , Interferon gama/metabolismo , Subunidade p40 da Interleucina-12/deficiência , Subunidade p40 da Interleucina-12/imunologia , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Plasmídeos , Proteínas de Protozoários/genética , Proteínas de Protozoários/imunologia , Vacinas Protozoárias/genética , Células Th1/imunologia , Células Th2/imunologia , Vacinas de DNA/genética
17.
J Infect Dis ; 202(3): 452-8, 2010 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-20575658

RESUMO

Highly pathogenic H5N1 avian influenza is considered an avian disease, although there is some evidence of limited human-to-human transmission of the virus. A global effort is underway to control or eradicate the highly pathogenic H5N1 avian influenza virus in poultry and prevent human exposure, both of which may also reduce the risk of pandemic emergence. Hemagglutinin gene sequences from 215 human H5N1 influenza viruses were used to trace the source and dispersal pattern of human H5N1 influenza viruses on a global scale. A mutation network and phylogenetic analyses of the hemagglutinin gene show that human H5N1 influenza viruses can be clearly divided among 4 clusters across geographic space. On the basis of analysis of the N-glycosylation sites at positions 100 and 170 in the hemagglutinin protein, human H5N1 influenza viruses were also divided into 3 types. When we combined these analyses with geographic information system data analyses, we found that Southern China is often a common source of multiple clusters of H5N1 influenza viruses and that each cluster has different dispersal patterns and individual evolutionary features. In summary, the genetic evidence presented here provides clear evidence for multiple clusters of human H5N1 influenza viruses that initially originated in Southern China.


Assuntos
Virus da Influenza A Subtipo H5N1/classificação , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Influenza Humana/epidemiologia , Influenza Humana/virologia , Polimorfismo Genético , Motivos de Aminoácidos , Animais , China/epidemiologia , Análise por Conglomerados , Genótipo , Geografia , Glicosilação , Hemaglutininas Virais/genética , Humanos , Virus da Influenza A Subtipo H5N1/genética , Modelos Moleculares , Epidemiologia Molecular , Filogenia , Estrutura Terciária de Proteína , Análise de Sequência de DNA , Homologia de Sequência
18.
Int J Pharm ; 392(1-2): 57-63, 2010 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-20302925

RESUMO

Skin photo-ageing induced by ultraviolet (UV) radiation is mainly ascribed to oxidative stress and reactive oxygen species (ROS). Coenzyme Q10 (CoQ10) has been reported as a powerful antioxidant in plasma. However, CoQ10 was barely satisfactory in topical drug delivery because of its lipid solubility. To improve the anti-oxidative efficiency of CoQ10 in skin photo-ageing, the present research prepared a novel CoQ10 nano-structured lipid carrier (CoQ10-NLC) and characterised it by size and freeze-fracture transmission electron microscopy (FF-TEM). In UVA-irradiated fibroblasts, the protection of CoQ10-NLC was more effective than the CoQ10-emulsion as demonstrated by cell viability and morphological changes of the cell body and nucleus. In addition, malondialdehyde (MDA, the product of lipid peroxidation) concentration decreased by 61.5% in the group treated with CoQ10-NLC compared to the group subjected to general CoQ10-emulsion. In the presence of CoQ10-NLC, the activities of the anti-oxidative enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) were reinstated to 81% and 75%, respectively, of the control group. In vivo, the CoQ10-NLC displayed a stronger capability to penetrate the stratum corneum and permeate the dermis after a topical skin application. These results reveal that CoQ10-NLC has greater antioxidant properties and topical skin penetration than the CoQ10-emulsion.


Assuntos
Portadores de Fármacos/química , Lipídeos/química , Nanoestruturas/química , Envelhecimento da Pele , Protetores Solares/administração & dosagem , Ubiquinona/análogos & derivados , Animais , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Células Cultivadas , Feminino , Fibroblastos/efeitos dos fármacos , Fibroblastos/enzimologia , Fibroblastos/metabolismo , Fibroblastos/patologia , Fibroblastos/efeitos da radiação , Glutationa Peroxidase/metabolismo , Humanos , Peróxidos Lipídicos/metabolismo , Microscopia Eletrônica de Transmissão , Modelos Biológicos , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/efeitos da radiação , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Pele/efeitos dos fármacos , Pele/enzimologia , Pele/metabolismo , Pele/efeitos da radiação , Absorção Cutânea/efeitos dos fármacos , Envelhecimento da Pele/efeitos dos fármacos , Envelhecimento da Pele/efeitos da radiação , Solubilidade , Protetores Solares/química , Protetores Solares/farmacocinética , Superóxido Dismutase/metabolismo , Propriedades de Superfície , Ubiquinona/administração & dosagem , Ubiquinona/química , Ubiquinona/farmacocinética , Raios Ultravioleta/efeitos adversos
19.
BMB Rep ; 42(10): 648-54, 2009 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-19874709

RESUMO

Overexpression of phospholipid hydroperoxide glutathione peroxidase (PHGPx) genes has been reported to play an important role in protecting host cells from oxidative injury in several model systems. A radish phospholipid hydroperoxide glutathione peroxidase (RsPHGPx) known to have high catalytic activity was applied to mouse 3T3 fibroblasts to determine the protective effects of PHGPx against oxidative injury triggered by hydroperoxides such as hydrogen peroxide (H(2)O(2)), tert-butyl hydroperoxide (t-BHP) and phosphatidylcholine hydroperoxide (PCOOH). We observed that preincubation of cells with RsPHGPx significantly increased cell viability, reduced levels of malondialdehyde (MDA), inhibited generation of reactive oxygen species (ROS), and maintained natural cell shapes after treatment with H(2)O(2), t-BHP or PCOOH, indicating that the exogenous RsPHGPx can act as an effective hydroperoxide-scavenger and may also protect target cells from oxidative damage. These results suggest the possibility for use of RsPHGPx as a therapeutic protectant.


Assuntos
Citoproteção/efeitos dos fármacos , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Glutationa Peroxidase/farmacologia , Peróxido de Hidrogênio/toxicidade , Raphanus/enzimologia , Células 3T3 , Animais , Sobrevivência Celular/efeitos dos fármacos , Fibroblastos/metabolismo , Espaço Intracelular/efeitos dos fármacos , Espaço Intracelular/metabolismo , Camundongos , Fosfolipídeo Hidroperóxido Glutationa Peroxidase , Espécies Reativas de Oxigênio/metabolismo , Proteínas Recombinantes/farmacologia
20.
BMC Immunol ; 10: 55, 2009 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-19852827

RESUMO

BACKGROUND: Susceptibility or resistance to infection with Listeria monocytogenes correlates with Selenium (Se) deficiency in response to infection. RESULTS: Se-deficient mouse models of listeriosis were used to study the innate immune response during the course of L. monocytogenes infection. Blood samples from mouse models were used for Se status. The concentration of MDA, SOD, GPx and CAT in blood has revealed that lower Se level exist in Se-deficient mice. Intestine, mesenteric lymph node, liver, spleen and brain from each mouse were to study the bacterial burden in organs. The analysis of cell types of spleen from Se-deficient mice revealed that the ability of the host to elicit a rapid recruitment and activation of systemic innate immune response to infection was to a certain extent compromised under conditions of Se deficiency. The cytokine levels in the serum and cytokine expression levels in the livers from Se-deficient mice revealed that the innate immune response of Se-deficient mice was impaired throughout the course of infection. These results suggest that innate immune response is altered by Se deficiency after infection with L. monocytogenes. CONCLUSION: In conclusion, induced susceptibility of host resistance is associated with an impaired innate immune response following infection with L. monocytogenes in C57BL/6 Se-deficient mice.


Assuntos
Citocinas/metabolismo , Sistema Imunitário/imunologia , Listeria monocytogenes/imunologia , Listeriose/imunologia , Selênio/imunologia , Animais , Contagem de Células , Células Cultivadas , Citocinas/sangue , Citocinas/genética , Citocinas/imunologia , Suscetibilidade a Doenças , Comportamento Alimentar , Feminino , Glutationa Peroxidase/metabolismo , Sistema Imunitário/metabolismo , Sistema Imunitário/microbiologia , Sistema Imunitário/patologia , Imunidade Inata , Listeria monocytogenes/crescimento & desenvolvimento , Listeria monocytogenes/patogenicidade , Listeriose/sangue , Listeriose/enzimologia , Listeriose/genética , Listeriose/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Gravidez , Selênio/deficiência , Selênio/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA