Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Nat Protoc ; 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38755447

RESUMO

Making research data findable, accessible, interoperable and reusable (FAIR) is typically hampered by a lack of skills in technical aspects of data management by data generators and a lack of resources. We developed a Template Wizard for researchers to easily create templates suitable for consistently capturing data and metadata from their experiments. The templates are easy to use and enable the compilation of machine-readable metadata to accompany data generation and align them to existing community standards and databases, such as eNanoMapper, streamlining the adoption of the FAIR principles. These templates are citable objects and are available as online tools. The Template Wizard is designed to be user friendly and facilitates using and reusing existing templates for new projects or project extensions. The wizard is accompanied by an online template validator, which allows self-evaluation of the template (to ensure mapping to the data schema and machine readability of the captured data) and transformation by an open-source parser into machine-readable formats, compliant with the FAIR principles. The templates are based on extensive collective experience in nanosafety data collection and include over 60 harmonized data entry templates for physicochemical characterization and hazard assessment (cell viability, genotoxicity, environmental organism dose-response tests, omics), as well as exposure and release studies. The templates are generalizable across fields and have already been extended and adapted for microplastics and advanced materials research. The harmonized templates improve the reliability of interlaboratory comparisons, data reuse and meta-analyses and can facilitate the safety evaluation and regulation process for (nano) materials.

2.
J Funct Biomater ; 13(4)2022 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-36547545

RESUMO

In this work, the micro-arc oxidation method is used to fabricate surface-modified complex-structured titanium implant coatings to improve biocompatibility. Depending on the utilized electrolyte solution and micro-arc oxidation process parameters, three different types of coatings (one of them-oxide, another two-calcium phosphates) were obtained, differing in their coating thickness, crystallite phase composition and, thus, with a significantly different biocompatibility. An analytical approach based on X-ray computed tomography utilizing software-aided coating recognition is employed in this work to reveal their structural uniformity. Electrochemical studies prove that the coatings exhibit varying levels of corrosion protection. In vitro and in vivo experiments of the three different micro-arc oxidation coatings prove high biocompatibility towards adult stem cells (investigation of cell adhesion, proliferation and osteogenic differentiation), as well as in vivo biocompatibility (including histological analysis). These results demonstrate superior biological properties compared to unmodified titanium surfaces. The ratio of calcium and phosphorus in coatings, as well as their phase composition, have a great influence on the biological response of the coatings.

3.
NanoImpact ; 25: 100385, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35559891

RESUMO

Expectations for safer and sustainable chemicals and products are growing to comply with the United Nations and European strategies for sustainability. The application of Safe(r) by Design (SbD) in nanotechnology implies an iterative process where functionality, human health and safety, environmental and economic impact and cost are assessed and balanced as early as possible in the innovation process and updated at each step. The EU H2020 NanoReg2 project was the first European project to implement SbD in six companies handling and/or manufacturing nanomaterials (NMs) and nano-enabled products (NEP). The results from this experience have been used to develop these guidelines on the practical application of SbD. The SbD approach foresees the identification, estimation, and reduction of human and environmental risks as early as possible in the development of a NM or NEP, and it is based on three pillars: (i) safer NMs and NEP; (ii) safer use and end of life and (iii) safer industrial production. The presented guidelines include a set of information and tools that will help deciding at each step of the innovation process whether to continue, apply SbD measures or carry out further tests to reduce uncertainty. It does not intend to be a prescriptive protocol where all suggested steps have to be followed to achieve a SbD NM/NEP or process. Rather, the guidelines are designed to identify risks at an early state and information to be considered to identify those risks. Each company adapts the approach to its specific needs and circumstances as company decisions influence the way forward.


Assuntos
Nanoestruturas , Nanotecnologia , Humanos , Indústrias , Nanoestruturas/efeitos adversos , Incerteza
4.
Materials (Basel) ; 16(1)2022 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-36614523

RESUMO

To fix the bone in orthopedics, it is almost always necessary to use implants. Metals provide the needed physical and mechanical properties for load-bearing applications. Although widely used as biomedical materials for the replacement of hard tissue, metallic implants still confront challenges, among which the foremost is their low biocompatibility. Some of them also suffer from excessive wear, low corrosion resistance, infections and shielding stress. To address these issues, various coatings have been applied to enhance their in vitro and in vivo performance. When merged with the beneficial properties of various bio-ceramic or polymer coatings remarkable bioactive, osteogenic, antibacterial, or biodegradable composite implants can be created. In this review, bioactive and high-performance coatings for metallic bone implants are systematically reviewed and their biocompatibility is discussed. Updates in coating materials and formulations for metallic implants, as well as their production routes, have been provided. The ways of improving the bioactive coating performance by incorporating bioactive moieties such as growth factors, osteogenic factors, immunomodulatory factors, antibiotics, or other drugs that are locally released in a controlled manner have also been addressed.

5.
Pharmaceuticals (Basel) ; 14(12)2021 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-34959731

RESUMO

Here, we describe the synthesis, characterization, and biological activities of a series of 26 new styryl-2(3H)-benzothiazolone analogs of combretastatin-A4 (CA-4). The cytotoxic activities of these compounds were tested in several cell lines (EA.hy926, A549, BEAS-2B, MDA-MB-231, HT-29, MCF-7, and MCF-10A), and the relations between structure and cytotoxicity are discussed. From the series, compound (Z)-3-methyl-6-(3,4,5-trimethoxystyryl)-2(3H)-benzothiazolone (26Z) exhibits the most potent cytotoxic activity (IC50 0.13 ± 0.01 µM) against EA.hy926 cells. 26Z not only inhibits vasculogenesis but also disrupts pre-existing vasculature. 26Z is a microtubule-modulating agent and inhibits a spectrum of angiogenic events in EA.hy926 cells by interfering with endothelial cell invasion, migration, and proliferation. 26Z also shows anti-proliferative activity in CA-4 resistant cells with the following IC50 values: HT-29 (0.008 ± 0.001 µM), MDA-MB-231 (1.35 ± 0.42 µM), and MCF-7 (2.42 ± 0.48 µM). Cell-cycle phase-specific experiments show that 26Z treatment results in G2/M arrest and mitotic spindle multipolarity, suggesting that drug-induced centrosome amplification could promote cell death. Some 26Z-treated adherent cells undergo aberrant cytokinesis, resulting in aneuploidy that perhaps contributes to drug-induced cell death. These data indicate that spindle multipolarity induction by 26Z has an exciting chemotherapeutic potential that merits further investigation.

6.
Mater Sci Eng C Mater Biol Appl ; 128: 112289, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474840

RESUMO

Successful osseointegration, i.e. the fully functional connection of patient's bone and artificial implant depends on the response of the cells to the direct contact with the surface of the implant. The surface properties of the implant which trigger cell responses leading to its integration into the surrounding bone can be tailored by surface modifications or coating with thin layers. One potential material for such applications is ultrananocrystalline diamond (UNCD). It combines the exceptional mechanical properties of diamond with good biocompatibility and possibility of coating as thin uniform films on different substrates of biological interest. In the current work we firstly deposited UNCD films on titanium-coated substrates and applied oxygen or ammonia plasma to modify their surface properties. The as-grown and modified UNCD exhibited relatively smooth surfaces with topography dominated by rounded features. The modifications induced oxygen- or amino-terminated surfaces with increased hydrophilicity. In addition, the UNCD coatings exhibited very low coefficient of friction when diamond was used as a counterpart. As-grown and modified UNCD samples were applied to study the responses of human osteoblast MG63 cells triggered by surfaces with various terminations assessed by proteomic analysis. The results revealed that the coating of Ti with UNCD as well as the plasma modifications resulting in O- or NH2-terminated UNCD induced upregulation of proteins specific for cytoskeleton, cell membrane, and extracellular matrix (ECM) involved in the cell-ECM-surface interactions. Proteins from each of these groups, namely, vimentin, cadherin and fibronectin were further studied immunocytochemically and the results confirmed their increased abundance leading to improved cell-to-surface adhesion and cell-to-cell interactions. These findings demonstrate the potential of implant coating with UNCD and its surface modifications for better osseointegration and bone formation.


Assuntos
Proteoma , Titânio , Diamante , Humanos , Osteoblastos , Proteômica , Propriedades de Superfície
7.
Int J Mol Sci ; 22(12)2021 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-34198700

RESUMO

Vacuum cathodic arc TiN coatings with overlaying TiO2 film were deposited on polished and surface roughened by electron beam modification (EBM) Ti6Al4V alloy. The substrate microtopography consisted of long grooves formed by the liner scan of the electron beam with appropriate frequencies (500 (AR500) and 850 (AR850) Hz). EBM transformed the α + ß Ti6Al4V mixed structure into a single α'-martensite phase. Тhe gradient TiN/TiO2 films deposited on mechanically polished (AR) and EBM (AR500 and AR850) alloys share the same surface chemistry and composition (almost stoichiometric TiN, anatase and rutile in different ratios) but exhibit different topographies (Sa equal to approximately 0.62, 1.73, and 1.08 µm, respectively) over areas of 50 × 50 µm. Although the nanohardness of the coatings on AR500 and AR850 alloy (approximately 10.45 and 9.02 GPa, respectively) was lower than that measured on the film deposited on AR alloy (about 13.05 GPa), the hybrid surface treatment offered improvement in critical adhesive loads, coefficient of friction, and wear-resistance of the surface. In phosphate buffer saline, all coated samples showed low corrosion potentials and passivation current densities, confirming their good corrosion protection. The coated EBM samples cultured with human osteoblast-like MG63 cells demonstrated increased cell attachment, viability, and bone mineralization activity especially for the AR500-coated alloy, compared to uncoated polished alloy. The results underline the synergetic effect between the sub-micron structure and composition of TiN/TiO2 coating and microarchitecture obtained by EBM.


Assuntos
Ligas/química , Materiais Biocompatíveis/química , Eletroquímica , Elétrons , Titânio/química , Calcificação Fisiológica/fisiologia , Adesão Celular , Linhagem Celular Tumoral , Sobrevivência Celular , Módulo de Elasticidade , Fricção , Dureza , Humanos , Microscopia de Força Atômica , Difração de Raios X
8.
Nat Nanotechnol ; 16(6): 644-654, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34017099

RESUMO

Nanotechnology is a key enabling technology with billions of euros in global investment from public funding, which include large collaborative projects that have investigated environmental and health safety aspects of nanomaterials, but the reuse of accumulated data is clearly lagging behind. Here we summarize challenges and provide recommendations for the efficient reuse of nanosafety data, in line with the recently established FAIR (findable, accessible, interoperable and reusable) guiding principles. We describe the FAIR-aligned Nanosafety Data Interface, with an aggregated findability, accessibility and interoperability across physicochemical, bio-nano interaction, human toxicity, omics, ecotoxicological and exposure data. Overall, we illustrate a much-needed path towards standards for the optimized use of existing data, which avoids duplication of efforts, and provides a multitude of options to promote safe and sustainable nanotechnology.

9.
Eur J Med Chem ; 120: 121-33, 2016 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-27187864

RESUMO

In order to design and synthesize a new class of heterocyclic analogues of natural combretastatin A-4 and its synthetic derivative AVE8062, the benzoxazolone ring was selected as a scaffold for a bioisosteric replacement of the ring B of both molecules. A library of 28 cis- and trans-styrylbenzoxazolones was obtained by a modified Wittig reaction under Boden's conditions. Structures of the newly synthesized compounds bearing the 3,4,5-trimethoxy-, 3,4-dimethoxy-, 3,5-dimethoxy-, and 4-methoxystyryl fragment at position 4, 5, 6 or 7 of benzoxazolone core were determined on the basis of spectral and X ray data. The in vitro cytotoxicity of styrylbenzoxazolones against different cell lines was examined. Stilbene derivative 16Z, (Z)-3-methyl-6-(3,4,5-trimethoxystyryl)-2(3H)-benzoxazolone, showed highest antiproliferative potential of the series, with IC50 of 0.25 µM against combretastatin resistant cell line HT-29, 0.19 µM against HepG2, 0.28 µM against EA.hy926 and 0.73 µM against K562 cells. Furthermore, the results of flow cytometric analysis confirmed that 16Z induced cell cycle arrest in G2/M phase in the cell lines like combretastatin A-4. This arrest is followed by an abnormal exit of cells from mitosis without cytokinesis into a pseudo G1-like multinucleate state leading to late apoptosis and cell death. Accordingly, synthetic analogue 16Z was identified as the most promising potential anticancer agent in present study, and was selected as lead compound for further detailed investigations.


Assuntos
Antineoplásicos/química , Benzoxazóis/química , Bibenzilas/farmacologia , Bibliotecas de Moléculas Pequenas/síntese química , Antineoplásicos/farmacologia , Bibenzilas/química , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Resistência a Medicamentos/efeitos dos fármacos , Humanos , Estrutura Molecular
10.
Genet Test Mol Biomarkers ; 20(2): 67-73, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26670794

RESUMO

AIM: The purpose of this study was to evaluate the association of common polymorphisms in endothelial nitric oxide synthesis (eNOS; G894T) and renin-angiotensin-aldosterone system (angiotensin converting enzyme [ACE]-I/D, angiotensinogen-T704C, and angiotensin II receptor type 1-A1166C) as risk factors in the pathogenesis of coronary artery disease (CAD) in Bulgarian patients. METHODS: This study included 171 patients with CAD and 123 control subjects. Polymerase chain reaction-restriction fragment length polymorphism was used for studying the single-nucleotide polymorphisms. Statistical analysis was performed using statistical software PASW for Windows. RESULTS: A significantly higher percentage of the eNOS T894 allele was found in patients with acute coronary syndrome (ACS), compared to controls (p = 0.006) and patients with stable angina pectoris (SAP, p = 0.005). Results from a binary regression analysis suggested that eNOS T allele and ACE D allele carriers were more likely to develop ACS than controls (T allele odds ratio [OR] 2.585, p = 0.024; D allele OR 3.585, p = 0.046) and patients with SAP (T allele OR 2.955, p = 0.009; D allele OR 2.703, p = 0.05). Exploratory evaluation of gene-gene combinations showed a significant association between eNOS-G894T/ACE-I/D and ACS compared to controls (p = 0.022) and patients with SAP (p = 0.017). CONCLUSIONS: The eNOS G894T and ACE I/D polymorphisms are associated with an increased risk of developing ACS after adjusting for classical risk factors for atherosclerosis in the Bulgarian cohort.


Assuntos
Doença da Artéria Coronariana/genética , Óxido Nítrico Sintase Tipo III/genética , Peptidil Dipeptidase A/genética , Polimorfismo de Fragmento de Restrição , Sistema Renina-Angiotensina/genética , Adulto , Idoso , Bulgária , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
11.
Biomacromolecules ; 15(12): 4377-95, 2014 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-25320910

RESUMO

A novel approach for the preparation of nano- and microcapsules in aqueous solutions by using thermoresponsive polymer (TRP) templates (mesoglobules) is described. The method comprised three steps: formation of mesoglobules, coating the templates by seeded radical copolymerization, followed by core dissolution and core removal upon cooling. When mesoglobule entraps biomacromolecules during the process of their formation, it makes it possible to load a controlled amount of bioactive compounds without covalent attachment. Special attention is paid to the mesoglobule dissolution upon cooling, as well as their loading efficiency. Details on the outer shell formation and the possibilities for targeting ligands incorporation and control of the shell porosity are discussed. Finally, the seeded radical copolymerization was used for covering DNA complexes with cationic copolymers bearing TRP blocks. This Review is an attempt to convince researchers of the promising perspectives for using mesoglobules as potential reservoirs, carriers, and transferring agents for biologically active substances.


Assuntos
Técnicas de Transferência de Genes , Nanopartículas/química , Polímeros/química , Cápsulas/química , DNA , Humanos , Temperatura
12.
Bioorg Med Chem Lett ; 23(14): 4080-4, 2013 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-23768908

RESUMO

Stable, nanosized polyelectrolyte complexes between rationally designed thermally sensitive block copolymers and plasmid DNA (polyplexes) were formed and their in vitro transfection efficiency was tested. The polyplexes were further stabilized through encapsulation into a biodegradable polymer shell. Although reduced as compared to that of the corresponding polyplexes, the encapsulated systems still show acceptable transfection efficiency. That opens the possibility to tune the balance between the safe transport and efficient delivery of DNA into the cells.


Assuntos
Vetores Genéticos/metabolismo , Polímeros/química , Acrilamidas/química , Resinas Acrílicas , Células HEK293 , Humanos , Nanopartículas/química , Tamanho da Partícula , Polilisina/química , Transfecção
13.
J Mater Sci Mater Med ; 23(5): 1225-34, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22415360

RESUMO

The paper reports on a simple method of synthesizing [PEO(PCL)(2)] triarm star-shaped copolymers by a combination of Michael-addition type reaction and ring-opening polymerization. A Michael-addition reaction yielded a PEO end-capped by two hydroxyl groups-a [PEO(OH)(2)] macroinitiator-which was used for sequential building of PCL blocks. The macroinitiator and copolymers were analyzed by FTIR, (1)H NMR spectroscopy and SEC. The self-assembly behavior of the copolymers in aqueous media was studied by UV-Vis spectroscopy. The size and morphology of the obtained micelles were determined by TEM. None of the polymers had cytotoxic effects in vitro. Cellular uptake studies showed the accumulation of neutral red loaded micelles in the perinuclear area of human hepatocellular carcinoma cells revealing a cellular uptake associated with macropinocytosis and caveolae mediated endocytosis. The accumulation had a sustained effect over 3 days pointing at the potential application of the copolymers micelles as a drug delivery system.


Assuntos
Sistemas de Liberação de Medicamentos , Poliésteres/síntese química , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacocinética , Células Hep G2 , Humanos , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Espectroscopia de Ressonância Magnética , Micelas , Modelos Biológicos , Conformação Molecular , Poliésteres/química , Poliésteres/farmacocinética , Polimerização , Espectroscopia de Infravermelho com Transformada de Fourier , Tensoativos/síntese química , Tensoativos/química , Tensoativos/farmacocinética
14.
Folia Med (Plovdiv) ; 53(1): 19-27, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21644401

RESUMO

AIM: To study differences and prognostic effect of some factors on brain (B-type) natriuretic peptide (BNP) levels at discharge of patients with chronic heart failure (CHF) treated in accord with current treatment guidelines. PATIENTS AND METHODS: Eighty-five consecutive patients hospitalized for CHF were recruited into the study. A standardized study protocol was used for them including collection of blood samples for measurement of electrolytes, creatinine at baseline and BNP at discharge. High BNP levels were determined at values above the threshold value for the highest BNP quartile (> or = 463 pg/ml). Linear regression analyses were performed using the SPSS 16.0. RESULTS: High BNP levels at discharge were measured in 21 (24.7%) of the patients. Patients with persisting high BNP levels, despite the administered correct therapy, had significantly more frequently worse clinical and instrumental characteristics: pulmonary congestion (76.2% vs. 40.6%), IV NYHA functional class (23.8% vs. 4.7%), atrial fibrillation (AF) (71.4% vs. 35.9%) and ischemic etiology of HF (47.6% vs. 15.6%). Multivariate linear regression analysis (F = 7.1, p < 0.001) identified systolic blood pressure (SBP), AF and instrumental data for pulmonary congestion as significant and independent predictors of high BNP at discharge. CONCLUSIONS: There were statistically significant differences in the distribution and prognostic effect of the studied factors across the BNP levels. CHF patients with hypotension, AF and instrumental evidence for pulmonary congestion at admission are at higher risk of high BNP levels at discharge and require special care and clinical approach.


Assuntos
Insuficiência Cardíaca/sangue , Insuficiência Cardíaca/terapia , Peptídeo Natriurético Encefálico/sangue , Idoso , Biomarcadores/sangue , Distribuição de Qui-Quadrado , Comorbidade , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Alta do Paciente , Guias de Prática Clínica como Assunto , Valor Preditivo dos Testes , Prognóstico , Fatores de Risco , Resultado do Tratamento
15.
J Inherit Metab Dis ; 34(4): 917-21, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21499719

RESUMO

EXT1/EXT2-CDG (Multiple cartilagineous exostoses, hereditary multiple osteochondroma (MO); OMIM 133700/133701) are common defects of O-xylosylglycan glycosylation. The diagnostic criteria are at least two osteochondromas of the juxta-epiphyseal region of long bones with in the majority of cases a positive family history and/or mutation in one of the EXT genes. The authors report data on clinical symptoms and complications of 23 patients (from 16 families), discussing the family history, age of diagnosis, new clinical and molecular data. Fifteen mutations and large deletions, of which nine are new, were detected in the EXT1 and EXT2 gene by sequence analysis, FISH and MLPA analysis.


Assuntos
Exostose Múltipla Hereditária/genética , N-Acetilglucosaminiltransferases/genética , Adolescente , Adulto , Bulgária , Criança , Pré-Escolar , Defeitos Congênitos da Glicosilação/complicações , Defeitos Congênitos da Glicosilação/genética , Análise Mutacional de DNA/métodos , Exostose Múltipla Hereditária/complicações , Exostose Múltipla Hereditária/diagnóstico , Feminino , Predisposição Genética para Doença/genética , Humanos , Masculino , Pessoa de Meia-Idade , N-Acetilglucosaminiltransferases/fisiologia , Adulto Jovem
16.
BMC Genomics ; 11: 41, 2010 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-20082691

RESUMO

BACKGROUND: Chronic myelogenous leukemia (CML) results from the neoplastic transformation of a haematopoietic stem cell. The hallmark genetic abnormality of CML is a chimeric BCR/ABL1 fusion gene resulting from the Philadelphia chromosome rearrangement t(9;22)(q34;q11). Clinical and laboratory studies indicate that the BCR/ABL1 fusion protein is essential for initiation, maintenance and progression of CML, yet the event(s) driving the transformation from chronic phase to blast phase are poorly understood. RESULTS: Here we report multiple genome aberrations in a collection of 78 CML and 14 control samples by oligonucleotide array comparative genomic hybridization. We found a unique signature of genome deletions within the immunoglobulin heavy chain (IGH) and T cell receptor regions (TCR), frequently accompanied by concomitant loss of sequences within the short arm regions of chromosomes 7 and 9, including IKZF1, HOXA7, CDKN2A/2B, MLLT3, IFNA/B, RNF38, PAX5, JMJD2C and PDCD1LG2 genes. CONCLUSIONS: None of these genome losses were detected in any of the CML samples with myeloid transformation, chronic phase or controls, indicating that their presence is obligatory for the development of a malignant clone with a lymphoid phenotype. Notably, the coincidental deletions at IGH and TCR regions appear to precede the loss of IKZF1 and/or p16 genes in CML indicating a possible involvement of RAG in these deletions.


Assuntos
Crise Blástica/genética , Genes Codificadores dos Receptores de Linfócitos T , Cadeias Pesadas de Imunoglobulinas/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Deleção de Sequência , Crise Blástica/imunologia , Cromossomos Humanos Par 7 , Cromossomos Humanos Par 9 , Hibridização Genômica Comparativa , Biologia Computacional , Genes p16 , Humanos , Fator de Transcrição Ikaros/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/imunologia , Análise de Sequência com Séries de Oligonucleotídeos
17.
Acta Crystallogr Sect E Struct Rep Online ; 66(Pt 6): o1273, 2010 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-21579374

RESUMO

In the title compound, C(7)H(8)BNO(3), the mol-ecule lies on an inversion center leading to a statistical disorder of the B(OH)(2) and CONH(2) groups. In the crystal structure, mol-ecules are linked by N-H⋯O and O-H⋯O hydrogen bonds, forming sheets parallel to the bc plane. The B(OH)(2) and CONH(2) groups are twisted out of the mean plane of the benzene ring by 23.9 (5) and 24.6 (6)°, respectively.

18.
Toxicol Sci ; 89(2): 465-74, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16280379

RESUMO

Cadmium (Cd2+) is known to cause a selective disruption of the filamentous actin cytoskeleton in the smooth muscle-like renal mesangial cell. We examined the effect of Cd2+ on the distribution of the actin-severing protein, gelsolin. Over 8 h, CdCl2 (10 microM) caused a progressive shift of gelsolin from a diffuse perinuclear and cytoplasmic distribution to a pattern decorating F-actin filaments. Over this time filaments were decreased in number in many cells, and membrane ruffling was initiated. Western blotting and 125I-F-actin gel overlays demonstrated an increase in actin-binding gelsolin activity in the cytoskeletal fraction of cell extracts following Cd2+ treatment. In in vitro polymerization assays, gelsolin acted as a nucleating factor and increased the rate of polymerization. Cytosolic extracts also increased the polymerization rate. Addition of Cd2+ together with gelsolin further increased the rate of polymerization. Gelsolin enhanced depolymerization of purified actin, and Cd2+ partially suppressed this effect. However, cytoskeletal extracts from Cd2+-treated cells also markedly increased depolymerization, suggesting further that Cd2+ may activate cellular component(s) such as gelsolin for actin binding. We conclude that a major effect of Cd2+ on the mesangial cell cytoskeleton is manifest through activating the association of gelsolin with actin, with gelsolin's severing properties predominating under conditions found in Cd2+-treated cells.


Assuntos
Cloreto de Cádmio/toxicidade , Citoesqueleto/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Gelsolina/metabolismo , Células Mesangiais/efeitos dos fármacos , Animais , Western Blotting , Células Cultivadas , Citoesqueleto/metabolismo , Imuno-Histoquímica , Células Mesangiais/metabolismo , Ratos
19.
J Inorg Biochem ; 95(4): 321-33, 2003 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-12818803

RESUMO

During the last 2 decades it was proposed that atherogenesis was closely related to the homeostasis of homocysteine (hCys) and/or copper. We hypothesized that the physiological action of hCys may be connected with its ability to form complexes with Cu. Our results showed the presence of two different Cu-hCys complexes. At a molar ratio Cu:hCys 1:1, a blue complex most probably consistent with a tentative dimeric Cu(II)(2)(hCys)(2)(H(2)O)(2) formula was formed, with tetrahedral Cu coordination and anti-ferromagnetic properties. The redox processes between Cu(II) and hCys, in a molar ratio > or =1:3 led to formation of a second yellow Cu(I)hCys complex. Both Cu-hCys complexes affected the metabolism of extracellular thiols more than hCys alone and inhibited glutathione peroxidase-1 activity and mRNA abundance. The biological action of hCys and Cu-hCys complexes involved remodeling and phosphorylation of focal adhesion complexes and paxillin. The adhesive interactions of monocytes with an endothelial monolayer led to the redistribution of both paxillin and F-actin after all treatments, but the diapedesis of monocytes through endothelial cell monolayer was both greater and faster in the presence of the tentative Cu(II)(2)(hCys)(2)(H(2)O)(2) complex. Together, these observations suggest that Cu-hCys complexes actively participate in the biochemical responses of endothelial cells that are involved in the aethiopathogenesis of atherosclerosis.


Assuntos
Cobre/metabolismo , Cobre/farmacologia , Homocisteína/metabolismo , Homocisteína/farmacologia , Calorimetria , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Espectroscopia de Ressonância de Spin Eletrônica , Endotélio/citologia , Endotélio/efeitos dos fármacos , Endotélio/enzimologia , Endotélio/metabolismo , Adesões Focais/efeitos dos fármacos , Glutationa Peroxidase/metabolismo , Humanos , Espectroscopia de Ressonância Magnética , Magnetismo , Estrutura Molecular , Monócitos/citologia , Monócitos/efeitos dos fármacos , Compostos Organometálicos/química , Compostos Organometálicos/farmacologia , Fosforilação/efeitos dos fármacos , Fosfotirosina/metabolismo , Espectrofotometria Infravermelho
20.
J Biol Chem ; 277(37): 34471-9, 2002 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-12089160

RESUMO

Epidermal keratinocyte differentiation is accompanied by differential regulation of E2F genes, including up-regulation of E2F-5 and its concomitant association with the retinoblastoma family protein p130. This complex appears to play a role in irreversible withdrawal from the cell cycle in differentiating keratinocytes. We now report that keratinocyte differentiation is also accompanied by changes in E2F-5 subcellular localization, from the cytoplasm to the nucleus. To define the molecular determinants of E2F-5 nuclear import, we tested its ability to enter the nucleus in import assays in vitro using digitonin-permeabilized cells. We found that E2F-5 enters the nucleus through mediated transport processes that involve formation of nuclear pore complexes. It has been proposed that E2F-4 and E2F-5, which lack defined nuclear localization signal (NLS) consensus sequences, enter the nucleus in association with NLS-containing DP-2 or pRB family proteins. However, we show that nuclear import of E2F-5 only requires the first N-terminal 56 amino acid residues and is not dependent on interaction with DP or pRB family proteins. Because E2F-5 is predominantly cytoplasmic in undifferentiated keratinocytes and in other intact cells, we also examined whether this protein is subjected to active nuclear export. Indeed, E2F-5 is exported from the nucleus through leptomycin B-sensitive, CRM1-mediated transport, through a region corresponding to amino acid residues 130-154. This region excludes the DNA- and the p130-binding domains. Thus, the subcellular distribution of E2F-5 is tightly regulated in intact cells, through multiple functional domains that direct nucleocytoplasmic shuttling of this protein.


Assuntos
Transporte Ativo do Núcleo Celular , Núcleo Celular/metabolismo , Receptores Citoplasmáticos e Nucleares , Fatores de Transcrição/metabolismo , Sequência de Aminoácidos , Citoplasma/metabolismo , Proteínas de Ligação a DNA/metabolismo , Fator de Transcrição E2F2 , Fator de Transcrição E2F4 , Fator de Transcrição E2F5 , Humanos , Carioferinas , Queratinócitos/química , Dados de Sequência Molecular , Proteína do Retinoblastoma/metabolismo , Fatores de Transcrição/análise , Fatores de Transcrição/química , Células Tumorais Cultivadas , Proteína Exportina 1
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...