Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Annu Int Conf IEEE Eng Med Biol Soc ; 2017: 4297-4300, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29060847

RESUMO

Inpainting-based compression and reconstruction methodology can be applied to systems with limited resources to enable continuously monitor neurological activity. In this work, an approach based on sparse representations and K-SVD is augmented to a video processing in order to improve the recovery quality. That was mainly achieved by using another direction of spatial correlation and the extraction of cuboids across frames. The implementation of overlapping frames between the recorded data blocks avoids rising errors at the boundaries during the inpainting-based recovery. Controlling the electrode states per frame plays a key role for high data compression and precise recovery. The proposed 3D inpainting approach can compete with common methods like JPEG, JPEG2000 or MPEG-4 in terms of the degree of compression and reconstruction accuracy, which was applied on real measured local field potentials of a human patient.


Assuntos
Neurônios , Algoritmos , Compressão de Dados , Humanos
2.
Cancer Lett ; 404: 79-88, 2017 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-28716523

RESUMO

The ruthenium drug and GRP78 inhibitor KP1339/IT-139 has already demonstrated promising anticancer activity in a phase I clinical trial. This study aimed to identify mechanisms underlying increased sensitivity to KP1339 treatment. Based on a screen utilizing 23 cell lines, a small panel was selected to compare KP1339-sensitive and low-responsive models. KP1339 sensitivity was neither based on differences in ruthenium accumulation, nor sensitivity to oxidative stress or constituents of KP1339 (ruthenium chloride and indazole). Subsequently, the biochemical response to KP1339 was analyzed using whole genome expression arrays indicating that, while sensitive cell lines were characterized by "response to chemical stimuli" and "regulation of cell death", low-responsive cells preferentially activated pathways controlling cell cycle, DNA repair, and metabolism. Cell culture experiments confirmed that, while low-responsive cells executed cell cycle arrest in G2 phase, pronounced apoptosis induction via activation of caspase 8 was found in sensitive cells. Cell death induction is based on a unique disruption of the ER homeostasis by depletion of key cellular chaperones including GRP78 in combination with enhanced KP1339-mediated protein damage.


Assuntos
Antineoplásicos/farmacologia , Caspase 8/metabolismo , Retículo Endoplasmático/efeitos dos fármacos , Proteínas de Choque Térmico/antagonistas & inibidores , Compostos Organometálicos/farmacologia , Apoptose/efeitos dos fármacos , Western Blotting , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Reparo do DNA/efeitos dos fármacos , Retículo Endoplasmático/metabolismo , Chaperona BiP do Retículo Endoplasmático , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Homeostase/efeitos dos fármacos , Humanos , RNA Mensageiro/metabolismo , Rutênio/metabolismo
3.
Sensors (Basel) ; 17(4)2017 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-28375161

RESUMO

Implantable neuronal interfaces to the brain are an important keystone for future medical applications. However, entering this field of research is difficult since such an implant requires components from many different areas of technology. Since the complete avoidance of wires is important due to the risk of infections and other long-term problems, means for wirelessly transmitting data and energy are a necessity which adds to the requirements. In recent literature, many high-tech components for such implants are presented with remarkable properties. However, these components are typically not freely available for such a system. Every group needs to re-develop their own solution. This raises the question if it is possible to create a reusable design for an implant and its external base-station, such that it allows other groups to use it as a starting point. In this article, we try to answer this question by presenting a design based exclusively on commercial off-the-shelf components and studying the properties of the resulting system. Following this idea, we present a fully wireless neuronal implant for simultaneously measuring electrocorticography signals at 128 locations from the surface of the brain. All design files are available as open source.


Assuntos
Eletrocorticografia , Encéfalo , Interfaces Cérebro-Computador , Próteses e Implantes , Tecnologia sem Fio
4.
J Inorg Biochem ; 159: 37-44, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26908285

RESUMO

Overall binding affinity of sodium or indazolium cis/trans-[MCl4(1H-indazole)(NO)] (M = Ru, Os) complexes towards human serum albumin (HSA) and high molecular mass components of the blood serum was monitored by ultrafiltration. HSA was found to be mainly responsible for the binding of the studied ruthenium and osmium complexes. In other words, this protein can provide a depot for the compounds and can affect their biodistribution and transport processes. In order to elucidate the HSA binding sites tryptophan fluorescence quenching studies and displacement reactions with the established site markers warfarin and dansylglycine were performed. Conditional stability constants for the binding to sites I and II on HSA were computed showing that the studied ruthenium and osmium complexes are able to bind into both sites with moderately strong affinity (logK' = 4.4-5.1). Site I is slightly more favored over site II for all complexes. No significant differences in the HSA binding properties were found for these metal complexes demonstrating negligible influence of the type of counterion (sodium vs indazolium), the metal ion center identity (Ru vs. Os) or the position of the nitrosyl group on the binding event. Electron paramagnetic resonance spin labeling of HSA revealed that indazolium trans-[RuCl4(1H-indazole)(NO)] and long-chain fatty acids show competitive binding to HSA. Moreover, this complex has a higher affinity for site I, but when present in excess, it is able to bind to site II as well, and displace fatty acids.


Assuntos
Indazóis/química , Compostos Organometálicos/química , Osmio/química , Rutênio/química , Albumina Sérica/química , Humanos
5.
Chemistry ; 21(39): 13703-13, 2015 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-26260662

RESUMO

A series of heteropentanuclear oxalate-bridged Ru(NO)-Ln (4d-4f) metal complexes of the general formula (nBu4N)5[Ln{RuCl3(µ-ox)(NO)}4], where Ln=Y (2), Gd (3), Tb (4), Dy (5) and ox=oxalate anion, were obtained by treatment of (nBu4N)2[RuCl3(ox)(NO)] (1) with the respective lanthanide salt in 4:1 molar ratio. The compounds were characterized by elemental analysis, IR spectroscopy, electrospray ionization (ESI) mass spectrometry, while 1, 2, and 5 were in addition analyzed by X-ray crystallography, 1 by Ru K-edge XAS and 1 and 2 by (13)C NMR spectroscopy. X-ray diffraction showed that in 2 and 5 four complex anions [RuCl3(ox)(NO)](2-) are coordinated to Y(III) and Dy(III), respectively, with formation of [Ln{RuCl3(µ-ox)(NO)}4](5-) (Ln=Y, Dy). While Y(III) is eight-coordinate in 2, Dy(III) is nine-coordinate in 5, with an additional coordination of an EtOH molecule. The negative charge is counterbalanced by five nBu4N(+) ions present in the crystal structure. The stability of complexes 2 and 5 in aqueous medium was monitored by UV/Vis spectroscopy. The antiproliferative activity of ruthenium-lanthanide complexes 2-5 were assayed in two human cancer cell lines (HeLa and A549) and in a noncancerous cell line (MRC-5) and compared with those obtained for the previously reported Os(NO)-Ln (5d-4f) analogues (nBu4N)5[Ln{OsCl3(ox)(NO)}4] (Ln=Y (6), Gd (7), Tb (8), Dy (9)). Complexes 2-5 were found to be slightly more active than 1 in inhibiting the proliferation of HeLa and A549 cells, and significantly more cytotoxic than 5d-4f metal complexes 6-9 in terms of IC50 values. The highest antiproliferative activity with IC50 values of 20.0 and 22.4 µM was found for 4 in HeLa and A549 cell lines, respectively. These cytotoxicity results are in accord with the presented ICP-MS data, indicating five- to eightfold greater accumulation of ruthenium versus osmium in human A549 cancer cells.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Complexos de Coordenação/química , Complexos de Coordenação/farmacologia , Óxidos de Nitrogênio/química , Antineoplásicos/química , Linhagem Celular Tumoral , Cristalografia por Raios X , Células HeLa , Humanos , Concentração Inibidora 50 , Ligantes , Estrutura Molecular , Rutênio/química
6.
Inorg Chem ; 53(20): 11130-9, 2014 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-25290960

RESUMO

A one-electron reduction of osmium(IV) complexes trans-[Os(IV)Cl4(Hazole)2], where Hazole = 1H-pyrazole ([1](0)), 2H-indazole ([2](0)), 1H-imidazole ([3](0)), and 1H-benzimidazole ([4](0)), afforded a series of eight new complexes as osmium analogues of KP1019, a lead anticancer drug in clinical trials, with the general formula (cation)[trans-Os(III)Cl4(Hazole)2], where cation = H2pz(+) (H2pz[1]), H2ind(+) (H2ind[2]), H2im(+) (H2im[3]), Ph4P(+) (Ph4P[3]), nBu4N(+) (nBu4N[3]), H2bzim(+) (H2bzim[4]), Ph4P(+) (Ph4P[4]), and nBu4N(+) (nBu4N[4]). All complexes were characterized by elemental analysis, (1)H NMR spectroscopy, electrospray ionization mass spectrometry, UV-vis spectroscopy, cyclic voltammetry, while H2pz[1], H2ind[2], and nBu4[3], in addition, by X-ray diffraction. The reduced species [1](-) and [4](-) are stable in aqueous media in the absence of air oxygen and do not react with small biomolecules such as amino acids and the nucleotide 5'-dGMP. Cell culture experiments in five different human cancer cell lines (HeLa, A549, FemX, MDA-MB-453, and LS-174) and one noncancerous cell line (MRC-5) were performed, and the results were discussed and compared to those for KP1019 and cisplatin. Benzannulation in complexes with similar structure enhances antitumor activity by several orders of magnitude, implicating different mechanisms of action of the tested compounds. In particular, complexes H2ind[2] and H2bzim[4] exhibited significant antiproliferative activity in vitro when compared to H2pz[1] and H2im[3].


Assuntos
Antineoplásicos/farmacologia , Técnicas Eletroquímicas , Indazóis/farmacologia , Compostos Organometálicos/farmacologia , Osmio/química , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células HeLa , Humanos , Hidrólise , Indazóis/síntese química , Indazóis/química , Modelos Moleculares , Estrutura Molecular , Compostos Organometálicos/síntese química , Compostos Organometálicos/química , Compostos de Rutênio , Espectrofotometria Ultravioleta , Relação Estrutura-Atividade
7.
Inorg Chem ; 52(11): 6260-72, 2013 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-23675748

RESUMO

Synthesis and X-ray diffraction structures of cis and trans isomers of ruthenium and osmium metal complexes of general formulas (nBu4N)[cis-MCl4(NO)(Hind)], where M = Ru (1) and Os (3), and (nBu4N)[trans-MCl4(NO)(Hind)], where M = Ru (2) and Os (4) and Hind = 1H-indazole are reported. Interconversion between cis and trans isomers at high temperatures (80-130 °C) has been observed and studied by NMR spectroscopy. Kinetic data indicate that isomerizations correspond to reversible first order reactions. The rates of isomerization reactions even at 110 °C are very low with rate constants of 10(-5) s(-1) and 10(-6) s(-1) for ruthenium and osmium complexes, respectively, and the estimated rate constants of isomerization at room temperature are of ca. 10(-10) s(-1). The activation parameters, which have been obtained from fitting the reaction rates at different temperatures to the Eyring equation for ruthenium [ΔH(cis-trans)‡ = 122.8 ± 1.3; ΔH(trans-cis)‡ = 138.8 ± 1.0 kJ/mol; ΔS(cis-trans)‡ = -18.7 ± 3.6; ΔS(trans-cis)‡ = 31.8 ± 2.7 J/(mol·K)] and osmium [ΔH(cis-trans)‡ = 200.7 ± 0.7; ΔH(trans-cis)‡ = 168.2 ± 0.6 kJ/mol; ΔS(cis-trans)‡ = 142.7 ± 8.9; ΔS(trans-cis)‡ = 85.9 ± 3.9 J/(mol·K)] reflect the inertness of these systems. The entropy of activation for the osmium complexes is highly positive and suggests the dissociative mechanism of isomerization. In the case of ruthenium, the activation entropy for the cis to trans isomerization is negative [-18.6 J/(mol·K)], while being positive [31.0 J/(mol·K)] for the trans to cis conversion. The thermodynamic parameters for cis to trans isomerization of [RuCl4(NO)(Hind)]-, viz. ΔH° = 13.5 ± 1.5 kJ/mol and ΔS° = -5.2 ± 3.4 J/(mol·K) indicate the low difference between the energies of cis and trans isomers. The theoretical calculation has been carried out on isomerization of ruthenium complexes with DFT methods. The dissociative, associative, and intramolecular twist isomerization mechanisms have been considered. The value for the activation energy found for the dissociative mechanism is in good agreement with experimental activation enthalpy. Electrochemical investigation provides further evidence for higher reactivity of ruthenium complexes compared to that of osmium counterparts and shows that intramolecular electron transfer reactions do not affect the isomerization process. A dissociative mechanism of cis↔trans isomerization has been proposed for both ruthenium and osmium complexes.


Assuntos
Azóis/química , Compostos Nitrosos/química , Compostos Organometálicos/química , Osmio/química , Rutênio/química , Cristalografia por Raios X , Modelos Moleculares , Estrutura Molecular , Compostos Organometálicos/síntese química , Teoria Quântica , Estereoisomerismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...