Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 96
Filtrar
Mais filtros

Bases de dados
Tipo de documento
Intervalo de ano de publicação
1.
Artigo em Inglês | MEDLINE | ID: mdl-39501471

RESUMO

BACKGROUND: Antithyroid drugs (ATDs) are the preferred treatment option for Graves' disease (GD), yet there is a lack of systematic evaluations studying the relationship between treatment duration and therapeutic outcomes. This study aims to assess the remission rate (RR) in children with GD under ATDs therapy and to conduct an analysis of associated factors. METHOD: Systematically searched PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure and Wanfang database, with a search time limit from the establishment of the database to 23 November 2023. The primary outcome was the RR. The pooled RR was calculated and subgroup comparisons were performed. Meta-analysis was conducted using R Studio 2023.09.0 + 463 software. RESULTS: The study incorporated a total of 19 research projects, which collectively involved 3359 paediatric patients diagnosed with GD (comprising 2600 girls and 759 boys). The overall RR for paediatric GD treated with ATDs was 25.4% (95% Confidence Interval [CI]: 20.7%, 30.1%). The pooled RR following treatment durations of < 2 years, 2-5 years, and > 5 years were respectively 15.5%, 24.1% and 33.0%. Meta-regression results indicated that the duration of treatment and follow-up duration were significant sources of high heterogeneity among the studies. Specifically, for every additional year of ATDs treatment, there was an increase in the RR by 3.8% (Coefficient = 3.8%, 95% CI: 0.6%, 7.0%, p < 0.01). CONCLUSION: The overall RR for the treatment of paediatric GD with ATDs is 25.4%, and prolonging the treatment course can indeed lead to an increased RR.

2.
Mol Pharm ; 21(4): 2012-2024, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38497779

RESUMO

The nonviral delivery systems that combine genes with photosensitizers for multimodal tumor gene/photodynamic therapy (PDT) have attracted much attention. In this study, a series of ROS-sensitive cationic bola-lipids were applied for the gene/photosensitizer codelivery. Zn-DPA was introduced as a cationic headgroup to enhance DNA binding, while the hydrophobic linking chains may facilitate the formation of lipid nanoparticles (LNP) and the encapsulation of photosensitizer Ce6. The length of the hydrophobic chain played an important role in the gene transfection process, and 14-TDZn containing the longest chains showed better DNA condensation, gene transfection, and cellular uptake. 14-TDZn LNPs could well load photosensitizer Ce6 to form 14-TDC without a loss of gene delivery efficiency. 14-TDC was used for codelivery of p53 and Ce6 to achieve enhanced therapeutic effects on the tumor cell proliferation inhibition and apoptosis. Results showed that the codelivery system was more effective in the inhibition of tumor cell proliferation than individual p53 or Ce6 monotherapy. Mechanism studies showed that the production of ROS after Ce6 irradiation could increase the accumulation of p53 protein in tumor cells, thereby promoting caspase-3 activation and inducing apoptosis, indicating some synergistic effect. These results demonstrated that 14-TDC may serve as a promising nanocarrier for gene/PDT combination therapy.


Assuntos
Lipossomos , Nanopartículas , Fotoquimioterapia , Porfirinas , Fármacos Fotossensibilizantes/química , Fotoquimioterapia/métodos , Espécies Reativas de Oxigênio/metabolismo , Proteína Supressora de Tumor p53/genética , Linhagem Celular Tumoral , Nanopartículas/química , DNA , Porfirinas/química
3.
Bioorg Med Chem ; 100: 117635, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38340641

RESUMO

Although many types of cationic lipids have been developed as efficient gene vectors, the construction of lipid molecules with simple procedures remains challenging. Passerini reaction, as a classic multicomponent reaction, could directly give the α-acyloxycarboxamide products with biodegradable ester and amide bonds. Herein, two series of novel cationic lipids with heterocyclic pyrrolidine and piperidine as headgroups were synthesized through Passerini reaction (P-series) and amide condensation (A-series), and relevant structure-activity relationships on their gene delivery capability was studied. It was found that although both of the two series of lipids could form lipid nanoparticles (LNPs) which could effectively condense DNA, the LNP derived from P-series lipids showed higher transfection efficiency, serum tolerance, cellular uptake, and lower cytotoxicity. Unlike the A-series LNPs, the P-series LNPs showed quite different structure-activity relationship, in which the relative site of the secondary amine had significant effect on the transfection performance. The othro-isomers of the P-series lipids had lower cytotoxicity, but poor transfection efficiency, which was probably due to their unstable nature. Taken together, this study not only validated the feasibility of Passerini reaction for the construction of cationic lipids for gene delivery, but also afforded some clues for the rational design of effective non-viral lipidic gene vectors.


Assuntos
Técnicas de Transferência de Genes , Lipídeos , Humanos , Lipídeos/farmacologia , Lipídeos/química , Relação Estrutura-Atividade , Transfecção , Cátions/química , Amidas
4.
Biomed Chromatogr ; 38(5): e5838, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38342982

RESUMO

Strobilanthes sarcorrhiza (CTS) is a medicinal plant with various pharmacological effects such as tonifying kidney and anti-inflammatory. However, the chemical composition and difference of its four parts (leaves, stems, rhizomes, and root tubers) have been rarely reported. In this study, ultrafast flow liquid chromatography coupled with quadrupole-time-of-flight MS was applied to analyze the chemical profile of CTS and identify 55 compounds, including terpenoids, phenylethanol glycosides, fatty acid derivatives, chain glycosides, flavonoid glycosides, and others. Among these compounds, 34 compounds were first identified in CTS. They were mainly terpenoids, phenylethanol glycosides, fatty acid derivatives, and so forth. Multivariate statistical analysis, such as principal component analysis and orthogonal partial least squares-discriminant analysis were also used to evaluate the difference in chemical compounds from the four parts of CTS. The results showed that phenylethanol glycosides were the main compounds of the underground parts, while terpenoids were the main compounds of the aboveground parts. This study revealed the chemical diversity and similarity of CTS and suggested that the rhizomes could be used as an alternative medicinal part to improve the resource utilization of CTS.


Assuntos
Espectrometria de Massas , Análise Multivariada , Espectrometria de Massas/métodos , Cromatografia Líquida/métodos , Extratos Vegetais/química , Terpenos/análise , Terpenos/química , Glicosídeos/análise , Glicosídeos/química , Cromatografia Líquida de Alta Pressão/métodos
5.
Hepatobiliary Pancreat Dis Int ; 23(3): 272-287, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37407412

RESUMO

BACKGROUND: Hepatocellular carcinoma (HCC) has a poor long-term prognosis. The competition of circular RNAs (circRNAs) with endogenous RNA is a novel tool for predicting HCC prognosis. Based on the alterations of circRNA regulatory networks, the analysis of gene modules related to HCC is feasible. METHODS: Multiple expression datasets and RNA element targeting prediction tools were used to construct a circRNA-microRNA-mRNA network in HCC. Gene function, pathway, and protein interaction analyses were performed for the differentially expressed genes (DEGs) in this regulatory network. In the protein-protein interaction network, hub genes were identified and subjected to regression analysis, producing an optimized four-gene signature for prognostic risk stratification in HCC patients. Anti-HCC drugs were excavated by assessing the DEGs between the low- and high-risk groups. A circRNA-microRNA-hub gene subnetwork was constructed, in which three hallmark genes, KIF4A, CCNA2, and PBK, were subjected to functional enrichment analysis. RESULTS: A four-gene signature (KIF4A, CCNA2, PBK, and ZWINT) that effectively estimated the overall survival and aided in prognostic risk assessment in the The Cancer Genome Atlas (TCGA) cohort and International Cancer Genome Consortium (ICGC) cohort was developed. CDK inhibitors, PI3K inhibitors, HDAC inhibitors, and EGFR inhibitors were predicted as four potential mechanisms of drug action (MOA) in high-risk HCC patients. Subsequent analysis has revealed that PBK, CCNA2, and KIF4A play a crucial role in regulating the tumor microenvironment by promoting immune cell invasion, regulating microsatellite instability (MSI), and exerting an impact on HCC progression. CONCLUSIONS: The present study highlights the role of the circRNA-related regulatory network, identifies a four-gene prognostic signature and biomarkers, and further identifies novel therapy for HCC.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , MicroRNAs , Humanos , RNA Circular/genética , Prognóstico , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/terapia , RNA Endógeno Competitivo , Fosfatidilinositol 3-Quinases , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/terapia , MicroRNAs/genética , Microambiente Tumoral , Cinesinas
6.
J Am Chem Soc ; 2023 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-37922444

RESUMO

The assembly of single-core molybdate into hundreds of cores of giant molybdenum blue (Mo-blue) clusters has remained a long-standing unresolved scientific puzzle. To reveal this fascinating self-assembly behavior, we demonstrate an aqueous flowing in-operando Raman characterization system to capture the building blocks' evolution from the "black box" reaction process. We successfully visualized the sequential transformation of Na2MoO4 into Mo7O246- ({Mo7}), high nuclear Mo36O1128- ({Mo36}) cluster, and finally polymerization product of [H6K2Mo3O12(SO4)]n ({Mo3(SO4)}n) during the H2SO4 acidification. Notably, the facile conversion of {Mo3(SO4)}n back to the {Mo36} cluster by simple dilution is also discovered. Furthermore, we identified {Mo36} and {Mo3(SO4)}n as exclusive precursors responsible for driving the electrochemical self-assembly of {Mo154} and {Mo102}, respectively. The study also unravels a pivotal intermediate, the pentagonal reduced state fragment [H18MoVI4MoVO24]-, originating from {Mo36}, which catalyzes the autocatalytic self-assembly of {Mo154} with electron and proton injection during electrochemical processes. Concurrently, {Mo3(SO4)}n serves as the indispensable precursor for {Mo102} formation, generating sulfation pentagon building blocks of [H2Na2O2(H4MoVMoVI4O16SO4)4]4- that facilitate the consecutive assembly of giant {Mo102} sphere clusters. As a result, a complete elucidation of the assembly pathway of giant Mo-blue clusters derived from single-core molybdate was obtained, and H+/e- redox couple is revealed to play a critical role in catalyzing the deassembly of the precursor, leading to the formation of thermodynamically stable intermediates essential for further self-assembly of reduced state giant clusters.

7.
Plant Dis ; 2023 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-36611243

RESUMO

Pecan (Carya illinoinensis K. Koch) is an important and widely planted nut tree species in Jiangsu Province, China (Mo et al. 2018). In July 2020, leaf spot symptoms were frequently observed on pecan in Jurong, Jiangsu Province (119°15'36"E, 32°1'6"N). Disease incidences ranged from 40 to 65% among 150 mature pecan trees from three nurseries. The disease severity index (DSI, Jiang et al. 2019) reached 58.4. Symptoms began as small brown spots scattered on leaves that gradually expanded to large, circular to irregular black and brown necrotic lesions. In severe cases, lesions developed on large portions of a single leaf, and eventually the dead leaves fell from the trees. Three monoconidial isolates (Chen2346, Chen2347, Chen2348) were isolated from lesion margins and cultured on potato dextrose agar (PDA) medium. Colonies on PDA were white and cottony, later becoming light gray with abundant reproductive structures. Sporangiophores were aseptate, hyaline, unbranched, and apically dilated to form a clavate vesicle, which produced sporangia. Sporangia were globular to ellipsoid, brown to dark brown, 103 to 128 µm in length, and 88 to 114 µm in width (n = 30). Sporangiola were brown, ellipsoid to ovoid, with longitudinal striae, and measured 13.9 to 18.8 × 7.9 to 10.8 µm (n = 60). The morphological characteristics of these isolates agreed with descriptions of Choanephora cucurbitarum (Kirk 1984). Genomic DNA of these three monoconidial isolates was extracted, and the partial sequences of the internal transcribed spacer (ITS) and large subunit (LSU) of rDNA were amplified using primer pairs ITS1/ITS4 (White et al. 1990) and LR0R/LR7 (Vilgalys and Hester 1990), respectively. The consensus sequences (GenBank accession nos.: OP315248 to OP315250 for ITS and OP315251 to OP315253 for LSU) were aligned using BLASTn and showed100% identity with the sequences from C. cucurbitarum found in GenBank (accession nos.: MF942131 for ITS and ON025788 for LSU). To further confirm the identity, a phylogenetic analysis was performed with MEGA (v.7.0) and MrBayes (v.3.1.2) software, using the maximum likelihood and Bayesian inference methods, respectively. The multigene phylogeny revealed that the three isolates in this study, as well as, C. cucurbitarum specimen, clustered as a strongly supported monophyletic group (99 bootstrap value; 0.95 posterior probabilities). Based on the morphological and molecular data, the isolates were identified as C. cucurbitarum. To confirm pathogenicity, healthy pecan seedlings (2 years old) were each inoculated with a mycelial block (3 × 3 mm) excised from the margin of a colony on the vein of each leaf. Seedlings treated with non-colonized PDA blocks were used as controls. The inoculated seedlings were maintained in sterile plastic boxes with moistened sheets of filter paper at 25 ± 1°C and a 12-h photoperiod. Fifteen leaves per isolate were tested for each treatment. The experiment was repeated twice. Three days after inoculation, symptoms similar to those in the field appeared, whereas the control leaves remained symptomless. Subsequently, C. cucurbitarum was reisolated from the lesions and morphologically identified, confirming Koch's postulates. To the best of our knowledge, this is the first report of C. cucurbitarum causing leaf spot on C. illinoinensis in China. This study provides the foundation to further investigate the biology, epidemiology, and management of this disease.

8.
J Am Chem Soc ; 144(20): 8951-8960, 2022 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-35536652

RESUMO

Aqueous solutions of polyoxometalates (POMs) have been shown to have potential as high-capacity energy storage materials due to their potential for multi-electron redox processes, yet the mechanism of reduction and practical limits are currently unknown. Herein, we explore the mechanism of multi-electron redox processes that allow the highly reduced POM clusters of the form {MO3}y to absorb y electrons in aqueous solution, focusing mechanistically on the Wells-Dawson structure X6[P2W18O62], which comprises 18 metal centers and can uptake up to 18 electrons reversibly (y = 18) per cluster in aqueous solution when the countercations are lithium. This unconventional redox activity is rationalized by density functional theory, molecular dynamics simulations, UV-vis, electron paramagnetic resonance spectroscopy, and small-angle X-ray scattering spectra. These data point to a new phenomenon showing that cluster protonation and aggregation allow the formation of highly electron-rich meta-stable systems in aqueous solution, which produce H2 when the solution is diluted. Finally, we show that this understanding is transferrable to other salts of [P5W30O110]15- and [P8W48O184]40- anions, which can be charged to 23 and 27 electrons per cluster, respectively.

9.
Nature ; 538(7626): 528-532, 2016 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-27760115

RESUMO

Mammalian genomes undergo epigenetic modifications, including cytosine methylation by DNA methyltransferases (DNMTs). Oxidation of 5-methylcytosine by the Ten-eleven translocation (TET) family of dioxygenases can lead to demethylation. Although cytosine methylation has key roles in several processes such as genomic imprinting and X-chromosome inactivation, the functional significance of cytosine methylation and demethylation in mouse embryogenesis remains to be fully determined. Here we show that inactivation of all three Tet genes in mice leads to gastrulation phenotypes, including primitive streak patterning defects in association with impaired maturation of axial mesoderm and failed specification of paraxial mesoderm, mimicking phenotypes in embryos with gain-of-function Nodal signalling. Introduction of a single mutant allele of Nodal in the Tet mutant background partially restored patterning, suggesting that hyperactive Nodal signalling contributes to the gastrulation failure of Tet mutants. Increased Nodal signalling is probably due to diminished expression of the Lefty1 and Lefty2 genes, which encode inhibitors of Nodal signalling. Moreover, reduction in Lefty gene expression is linked to elevated DNA methylation, as both Lefty-Nodal signalling and normal morphogenesis are largely restored in Tet-deficient embryos when the Dnmt3a and Dnmt3b genes are disrupted. Additionally, a point mutation in Tet that specifically abolishes the dioxygenase activity causes similar morphological and molecular abnormalities as the null mutation. Taken together, our results show that TET-mediated oxidation of 5-methylcytosine modulates Lefty-Nodal signalling by promoting demethylation in opposition to methylation by DNMT3A and DNMT3B. These findings reveal a fundamental epigenetic mechanism featuring dynamic DNA methylation and demethylation crucial to regulation of key signalling pathways in early body plan formation.


Assuntos
Metilação de DNA , Proteínas de Ligação a DNA/metabolismo , Dioxigenases/metabolismo , Gastrulação , Fatores de Determinação Direita-Esquerda/metabolismo , Proteína Nodal/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Transdução de Sinais , 5-Metilcitosina/metabolismo , Animais , DNA (Citosina-5-)-Metiltransferases/metabolismo , Metilação de DNA/genética , DNA Metiltransferase 3A , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Dioxigenases/deficiência , Dioxigenases/genética , Embrião de Mamíferos/embriologia , Embrião de Mamíferos/enzimologia , Embrião de Mamíferos/metabolismo , Elementos Facilitadores Genéticos/genética , Epigênese Genética , Feminino , Gastrulação/genética , Masculino , Mesoderma/embriologia , Mesoderma/metabolismo , Camundongos , Oxirredução , Regiões Promotoras Genéticas/genética , Proteínas Proto-Oncogênicas/deficiência , Proteínas Proto-Oncogênicas/genética , Transdução de Sinais/genética , DNA Metiltransferase 3B
10.
Hepatobiliary Pancreat Dis Int ; 20(6): 535-541, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34303609

RESUMO

BACKGROUND: Hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) has a high short-term mortality. However, the treatment progression for HBV-ACLF in China in the past decade has not been well characterized. The present study aimed to determine whether the HBV-ACLF treatment has significantly improved during the past decade. METHODS: This study retrospectively compared short-term (28/56 days) survival rates of two different nationwide cohorts (cohort I: 2008-2011 and cohort II: 2012-2015). Eligible HBV-ACLF patients were enrolled retrospectively. Patients in the cohorts I and II were assigned either to the standard medical therapy (SMT) group (cohort I-SMT, cohort II-SMT) or artificial liver support system (ALSS) group (cohort I-ALSS, cohort II-ALSS). Propensity score matching analysis was conducted to eliminate baseline differences, and multivariate logistic regression analysis was used to explore the independent factors for 28-day survival. RESULTS: Short-term (28/56 days) survival rates were significantly higher in the ALSS group than those in the SMT group (P < 0.05) and were higher in the cohort II than those in the cohort I (P < 0.001). After propensity score matching, short-term (28/56 days) survival rates were higher in the cohort II than those in the cohort I for both SMT (60.7% vs. 53.0%, 50.0% vs. 39.8%, P < 0.05) and ALSS (66.1% vs. 56.5%, 53.0% vs. 44.4%, P < 0.05) treatments. The 28-day survival rate was higher in patients treated with nucleos(t)ide analogs than in patients without such treatments (P = 0.046). Multivariate logistic regression analysis revealed that ALSS (OR = 0.962, 95% CI: 0.951-0.973, P = 0.038), nucleos(t)ide analogs (OR = 0.927, 95% CI: 0.871-0.983, P = 0.046), old age (OR = 1.028, 95% CI: 1.015-1.041, P < 0.001), total bilirubin (OR = 1.002, 95% CI: 1.001-1.003, P = 0.004), INR (OR = 1.569, 95% CI: 1.044-2.358, P < 0.001), COSSH-ACLF grade (OR = 2.683, 95% CI: 1.792-4.017, P < 0.001), and albumin (OR = 0.952, 95% CI: 0.924-0.982, P = 0.002) were independent factors for 28-day mortality. CONCLUSIONS: The treatment for patients with HBV-ACLF has improved in the past decade.


Assuntos
Insuficiência Hepática Crônica Agudizada , Hepatite B Crônica , Hepatite B , Insuficiência Hepática Crônica Agudizada/diagnóstico , Insuficiência Hepática Crônica Agudizada/terapia , China/epidemiologia , Estudos de Coortes , Hepatite B/complicações , Hepatite B/diagnóstico , Hepatite B/tratamento farmacológico , Vírus da Hepatite B , Hepatite B Crônica/complicações , Hepatite B Crônica/diagnóstico , Hepatite B Crônica/tratamento farmacológico , Humanos , Prognóstico , Pontuação de Propensão , Estudos Retrospectivos
11.
Zhongguo Zhong Yao Za Zhi ; 45(6): 1272-1278, 2020 Mar.
Artigo em Zh | MEDLINE | ID: mdl-32281336

RESUMO

Molecular biology is a new subject that clarifies the phenomena and nature of life at the molecular level. Its development provides new biotechnology and methods for the study of traditional pharmacognosy. The formation of molecular biology has brought the development of pharmacognosy into a new era of gene research. Lonicerae Japonicae Flos is a classical Chinese medicine. Many scholars of home and abroad have carried out relevant studies on its molecular biology on the basis of the in-depth study with traditional methods, and have achieved certain results. In order to provide references on the method, technical for promoting the modernization of Lonicerae Japonicae Flos, and the development, protection, and utilization of other traditional Chinese medicine resources. This article summarized the application status of molecular biology methods and techniques on the identification, biosynthesis of active constituents, and molecular mechanism of secondary metabolite under stress conditions of Lonicerae Japonicae Flos in recent years. In hybridization technology of tag(RFLP), molecular markers based on PCR(RAPD, AFLP, SSR and ISSR), based on DNA sequence analysis of SNP and DNA barcode for the variety identification, diagnosis, identification of Lonicerae Japonicae Flos, and so forth in detail. At the same time, it is proposed that multi-omics technology can be used to build systems biology technology and platforms, and establish related models of secondary metabolite biosynthesis, so as to deepen acknowledge the molecular mechanism of the active component biosynthesis of Lonicerae Japonicae Flos and the accumulation of metabolites, life activities of other medicinal plants under adverse environment, then to regulate them.


Assuntos
Medicamentos de Ervas Chinesas/farmacologia , Lonicera/química , Análise do Polimorfismo de Comprimento de Fragmentos Amplificados , Cromatografia Líquida de Alta Pressão , Código de Barras de DNA Taxonômico , Medicina Tradicional Chinesa , Repetições de Microssatélites , Plantas Medicinais/química , Polimorfismo de Fragmento de Restrição , Polimorfismo de Nucleotídeo Único , Técnica de Amplificação ao Acaso de DNA Polimórfico , Metabolismo Secundário
12.
New Phytol ; 224(1): 188-201, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31230359

RESUMO

Tissue regeneration upon wounding in plants highlights the developmental plasticity of plants. Previous studies have described the morphological and molecular changes of secondary vascular tissue (SVT) regeneration after large-scale bark girdling in trees. However, how phytohormones regulate SVT regeneration is still unknown. Here, we established a novel in vitro SVT regeneration system in the hybrid aspen (Populus tremula × Populus tremuloides) clone T89 to bypass the limitation of using field-grown trees. The effects of phytohormones on SVT regeneration were investigated by applying exogenous hormones and utilizing various transgenic trees. Vascular tissue-specific markers and hormonal response factors were also examined during SVT regeneration. Using this in vitro regeneration system, we demonstrated that auxin and cytokinin differentially regulate phloem and cambium regeneration. Whereas auxin is sufficient to induce regeneration of phloem prior to continuous cambium restoration, cytokinin only promotes the formation of new phloem, not cambium. The positive role of cytokinin on phloem regeneration was further confirmed in cytokinin overexpression trees. Analysis of a DR5 reporter transgenic line further suggested that cytokinin blocks the re-establishment of auxin gradients, which is required for the cambium formation. Investigation on the auxin and cytokinin signalling genes indicated these two hormones interact to regulate SVT regeneration. Taken together, the in vitro SVT regeneration system allows us to make use of various molecular and genetic tools to investigate SVT regeneration. Our results confirmed that complementary auxin and cytokinin domains are required for phloem and cambium reconstruction.


Assuntos
Citocininas/metabolismo , Ácidos Indolacéticos/metabolismo , Feixe Vascular de Plantas/fisiologia , Populus/fisiologia , Regeneração/fisiologia , Árvores/fisiologia , Câmbio/fisiologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Modelos Biológicos , Floema/fisiologia , Populus/genética , Árvores/genética
13.
Chemistry ; 25(49): 11432-11436, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31309625

RESUMO

We present strategies to tune the redox properties of polyoxometalate clusters to enhance the electron-coupled proton-buffer-mediated water splitting process, in which the evolution of hydrogen and oxygen can occur in different forms and is separated in time and space. By substituting the heteroatom template in the Keggin-type polyoxometalate cluster, H6 ZnW12 O40 , it is possible to double the number of electrons and protonation in the redox reactions (from two to four). This increase can be achieved with better matching of the energy levels as indicated by the redox potentials, compared to the ones of well-studied H3 PW12 O40 and H4 SiW12 O40 . This means that H6 ZnW12 O40 can act as a high-performance redox mediator in an electrolytic cell for the on-demand generation of hydrogen with a high decoupling efficiency of 95.5 % and an electrochemical energy efficiency of 83.3 %. Furthermore, the H6 ZnW12 O40 cluster also exhibits an excellent cycling behaviour and redox reversibility with almost 100 % H2 -mediated capacity retention during 200 cycles and a high coulombic efficiency >92 % each cycle at 30 mA cm-2 .

14.
BMC Infect Dis ; 19(1): 1000, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31775654

RESUMO

BACKGROUND: The prevalence of HIV among men who have sex with men (MSM) has become a significant public health challenge. The aim was to comprehensively estimate the national prevalence of HIV among MSM and its time trends through a large-scale systematic analysis. METHODS: Systematic search of Cochrane Library, PubMed, EMBASE, CNKI, VIP, and Wanfang Data databases without language restriction for studies on the prevalence of HIV among MSM published before Dec.31, 2018. Studies were eligible for inclusion if they were published in the peer-reviewed literature and used validated assessment methods to assess the prevalence of HIV among MSM. Estimates were pooled using random-effects analysis. RESULTS: Data were extracted from 355 cross-sectional studies (571,328 individuals) covered 59 cities from 30 provinces and municipalities of China. The overall national prevalence of HIV among MSM from 2001 to 2018 was estimated to be 5.7% (95% CI: 5.4-6.1%), with high between-study heterogeneity (I2 = 98.0%, P <  0.001). Our study showed an increased tendency in the HIV prevalence as time progressed by meta-regression analysis (I2 = 95.9%, P <  0.0001). HIV prevalence was the highest in those aged 50 years and older with HIV prevalence of 19.3% (95%CI: 13.1-27.4%, N = 13). HIV was more prevalent in the illiterate population (16.8%), than in those who had received an education. Although the internet was a major venue for Chinese MSM seeking male sex partners (35.6, 95%CI: 32.3-39.9%, N = 101), seeking MSM in bathhouses/saunas had the highest associated prevalence of HIV (13.4, 95%CI: 10.3-17.1%, N = 22). The HIV prevalence among MSM varied by location: compared with other regions in China, HIV was highly prevalent among MSM in the southwest (10.7, 95%CI: 9.3-12.2%, N = 91). Compared to participants who sometimes or always used condoms, participants who had never used a condom in the past 6 months had a higher risk of HIV infection, with odds ratios of 0.1 (95%CI: 0.08-0.14). CONCLUSIONS: Our analysis provided reliable estimates of China's HIV burden among MSM, which appears to present an increasing national public health challenge. Effective government responses are needed to address this challenge and include the implementation of HIV prevention.


Assuntos
Infecções por HIV/epidemiologia , Saúde Pública/métodos , Minorias Sexuais e de Gênero , Adolescente , Adulto , Fatores Etários , China/epidemiologia , Cidades/epidemiologia , Preservativos , Estudos Transversais , Infecções por HIV/prevenção & controle , Homossexualidade Masculina , Humanos , Internet , Alfabetização , Masculino , Pessoa de Meia-Idade , Razão de Chances , Prevalência , Parceiros Sexuais , Adulto Jovem
15.
J Am Chem Soc ; 140(8): 3134-3138, 2018 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-29425034

RESUMO

Investigations of the Ag (I)-substituted Keggin K3[H3AgIPW11O39] as a bifunctional Lewis acidic and basic catalyst are reported that explore the stabilization of Li2Sn moieties so that reversible redox reactions in S-based electrodes would be possible. Spectroscopic investigations showed that the Li2Sn-moieties can be strongly adsorbed on the {AgIPW11O39} cluster, where the Ag(I) ion can act as a Lewis acid site to further enhance the adsorption of the S-moieties, and these interactions were investigated and rationalized using DFT. These results were used to construct an electrode for use in a Li-S battery with a very high S utilization of 94%, and a coulometric capacity of 1580 mAh g-1. This means, as a result of using the AgPOM, both a high active S content, as well as a high areal S mass loading, is achieved in the composite electrode giving a highly stable battery with cycling performance at high rates (1050 and 810 mAh g-1 at 1C and 2C over 100 to 300 cycles, respectively).

16.
J Am Chem Soc ; 140(7): 2595-2601, 2018 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-29359931

RESUMO

Heteroanion (HA) moieties have a key role in templating of heteropolyoxometalate (HPA) architectures, but clusters templated by two different templates are rarely reported. Herein, we show how a cross-shaped HPA-based architecture can self-sort the HA templates by pairing two different guests into a divacant {XYW15O54} building block, with four of these building block units being linked together to complete the cross-shaped architecture. We exploited this observation to incorporate HA templates into well-defined positions within the clusters, leading to the isolation of a collection of mixed-HA templated cross-shaped polyanions [(XYW15O54)4(WO2)4]32-/36- (X = H-P, Y = Se, Te, As). The template positions have been unambiguously determined by single crystal X-ray diffraction, NMR spectroscopy, and high-resolution electrospray ionization mass spectrometry; these studies demonstrated that the mixed template containing HPA clusters are the preferred products which crystallize from the solution. Theoretical studies using DFT calculations suggest that the selective self-sorting originates from the coordination of the template in solution. The cross-shaped polyoxometalate clusters are redox-active, and the ability of molecules to accept electrons is slightly modulated by the HA incorporated as shown by differential pulse voltammetry experiments. These results indicate that the cross-shaped HPAs can be used to select templates from solution, and themselves have interesting geometries, which will be useful in developing functional molecular architectures based upon HPAs with well-defined structures and electronic properties.

17.
J Pharmacol Exp Ther ; 362(1): 67-77, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28450469

RESUMO

Overactivation of microglia contributes to the induction of neuroinflammation, which is highly involved in the pathology of many neurodegenerative diseases. Phosphodiesterase 4 (PDE4) represents a promising therapeutic target for anti-inflammation; however, the dose-limiting side effects, such as nausea and emesis, have impeded their clinic application. FCPR03, a novel selective PDE4 inhibitor synthesized in our laboratory, shows little or no emetic potency; however, the anti-inflammatory activities of FCPR03 in vitro and in vivo and the molecular mechanisms are still not clearly understood. This study was undertaken to delineate the anti-inflammatory effects of FCPR03 both in vitro and in vivo and explore whether these effects are regulated by PDE4-mediated signaling pathway. BV-2 microglial cells stimulated by lipopolysaccharide (LPS) and mice injected i.p. with LPS were established as in vitro and in vivo models of inflammation. Our results showed that FCPR03 dose dependently suppressed the production of tumor necrosis factor α, interleukin-1ß, and iinterleukin-6 in BV-2 microglial cells treated with LPS. The role of FCPR03 in the production of proinflammatory factors was reversed by pretreatment with protein kinase A (PKA) inhibitor H89. In addition, FCPR03 reduced the levels of proinflammatory factors in the hippocampus and cortex of mice injected with LPS. Our results further demonstrated that FCPR03 effectively increased the production of cAMP, promoted cAMP response element binding protein (CREB) phosphorylation, and inhibited nuclear factor κB (NF-κB) activation both in vitro and in vivo. Our findings suggest that FCPR03 inhibits the neuroinflammatory response through the activation of cAMP/PKA/CREB signaling pathway and NF-κB inhibition.


Assuntos
Benzamidas/uso terapêutico , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/fisiologia , Proteínas Quinases Dependentes de AMP Cíclico/fisiologia , AMP Cíclico/fisiologia , Mediadores da Inflamação/metabolismo , NF-kappa B/metabolismo , Inibidores da Fosfodiesterase 4/uso terapêutico , Animais , Benzamidas/química , Benzamidas/farmacologia , Linhagem Celular Transformada , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Relação Dose-Resposta a Droga , Feminino , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Inflamação/induzido quimicamente , Inflamação/metabolismo , Inflamação/prevenção & controle , Mediadores da Inflamação/antagonistas & inibidores , Lipopolissacarídeos/toxicidade , Masculino , Camundongos , Camundongos Endogâmicos C57BL , NF-kappa B/antagonistas & inibidores , Inibidores da Fosfodiesterase 4/química , Inibidores da Fosfodiesterase 4/farmacologia , Distribuição Aleatória , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia
18.
Mycologia ; 109(1): 27-34, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28402795

RESUMO

Onnia includes white rotting polypores with annual basidiocarps, a duplex context, monomitic hyphal structure, hymenial setae, and hyaline, thin-walled, smooth basidiospores. Specimens of Onnia, originating mainly from East Asia, Europe, and North America, were studied using both morphology and phylogenetic analyses. Our concatenated data set was derived from 25 collections and included (i) 25 nuc rDNA internal transcribed spacer region sequences (ITS1-5.8S-ITS2 = ITS), 17 generated in this study; and (ii) 14 nuc rDNA 28S rDNA sequences, including the D1-D2 domains, 11 of them generated in this study. The resulting maximum likelihood and Bayesian phylogenies recovered all sampled collections of Onnia as a well-supported clade. In this clade, three previously accepted species, viz., Onnia leporina, O. tomentosa, and O. triquetra, received strong support, whereas three additional lineages with strong support represent the new species described in this paper, O. subtriquetra, O. microspora, and O. tibetica. Of the six Onnia species occurring on gymnosperms, O. tomentosa and O. leporina grow mainly on Picea and have circumboreal distribution in the Northern Hemisphere. In contrast, other species that mostly grow on Pinus are geographically restricted to limited regions, viz., O. triquetra in Europe, O. subtriquetra in North America, and O. microspora and O. tibetica in Asia.


Assuntos
Basidiomycota/classificação , Basidiomycota/genética , Variação Genética , Filogeografia , Basidiomycota/citologia , Basidiomycota/isolamento & purificação , Análise por Conglomerados , DNA Fúngico/química , DNA Fúngico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Europa (Continente) , Ásia Oriental , Microscopia , América do Norte , Picea/microbiologia , Pinus/microbiologia , RNA Ribossômico 28S/genética , RNA Ribossômico 5,8S/genética , Análise de Sequência de DNA
19.
Cell Physiol Biochem ; 38(3): 939-49, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26938054

RESUMO

AIMS: Circulating microRNAs (miRNAs) as biomarkers for leukemia have been validated by emerging studies. This meta-analysis aims to estimate the overall diagnostic accuracy of blood-based circulating miRNAs for leukemia. METHODS: We searched multiple databases (PubMed, EMBASE, Cochrane Library, CNKI, Wan Fang Data and CQVIP) up to June 18, 2015. RESULTS: 32 studies from 10 publications were included in this meta-analysis. Diagnostic capacity was evaluated by pooled sensitivity, specifIcity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the curve (AUC) through random-effects model. Sensitivity analyses were sequentially performed to find potential sources of heterogeneity. The quality of included studies was assessed by QUADAS (quality assessment for studies of diagnostic accuracy). Meta-Disc 1.4 and Stata 12.0 software were used to perform the meta-analysis. A high diagnostic accuracy was displayed, with a sensitivity of 0.84, a specificity of 0.88, a PLR of 7.20, a NLR of 0.18, a DOR of 52, and an AUC of 0.94. Subgroup analyses revealed better performance for combined miRNAs, acute myeloid leukemia patients and Asian population than other subgroups. CONCLUSION: Our analyses suggested that blood-based circulating miRNAs are promising diagnostic biomarkers for leukemia, especially combined miRNAs. Its clinical application awaits further study.


Assuntos
Leucemia/diagnóstico , Leucemia/genética , MicroRNAs/sangue , Área Sob a Curva , Biomarcadores Tumorais/sangue , Biomarcadores Tumorais/genética , Detecção Precoce de Câncer , Regulação Leucêmica da Expressão Gênica , Humanos , Curva ROC
20.
Opt Express ; 24(11): 11531-8, 2016 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-27410080

RESUMO

The multiplexing transmission has always been a focus of attention for communication technology. In this paper, the radiation characteristics of circular microstrip patch antenna was firstly analyzed based on cavity model theory, and then spiral beams carrying orbital angular momentum (OAM) were generated, using elliptical microstrip patch antenna, with a single feed probe instead of a standard circular patch with two feedpoints. Moreover, by combining the proposed elliptic microstrip patch antenna with Universal Software Radio Peripheral (USRP), a wireless OAM transmission system was established and the real-time transmission of text, image and video in a real channel environment was realized. Since the wireless OAM transmission has the advantage of good safety and high spectrum utilization efficiency, this work has theoretical significance and potential application.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA