RESUMO
Microlipid vesicles (MLV) have a broad spectrum of applications for the delivery of molecules, ranging from chemical compounds to proteins, in both in vitro and in vivo conditions. In the present study, we developed a new set of nanosize multilayer lipid vesicles (NMVs) containing a unique combination of lipids. The NMVs enable the adsorption of histidine-tagged proteins at the vesicle surface and were demonstrated to be suitable for the in vivo delivery of antigens. The NMVs contained a combination of neutral (DOPC) and anionic (DPPG) lipids in the inner membrane and an external layer composed of DOPC, cholesterol, and a nickel-containing lipid (DGS-NTA [Ni]). NMVs combined with a recombinant form of the B subunit of the Shiga toxin (rStx2B) produced by certain enterohemorragic Escherichia coli (EHEC) strains enhanced the immunogenicity of the antigen after parenteral administration to mice. Mice immunized with rStx2B-loaded NMVs elicited serum antibodies capable of neutralizing the toxic activities of the native toxin; this result was demonstrated both in vitro and in vivo. Taken together, these results demonstrated that the proposed NMVs represent an alternative for the delivery of antigens, including recombinant proteins, generated in different expression systems.
Assuntos
Anticorpos Antibacterianos/imunologia , Sistemas de Liberação de Medicamentos/métodos , Escherichia coli Êntero-Hemorrágica/imunologia , Infecções por Escherichia coli/imunologia , Lipídeos/química , Toxina Shiga/imunologia , Animais , Formação de Anticorpos , Antígenos de Bactérias/administração & dosagem , Antígenos de Bactérias/química , Antígenos de Bactérias/imunologia , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos/instrumentação , Escherichia coli Êntero-Hemorrágica/genética , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/prevenção & controle , Feminino , Humanos , Imunização , Camundongos , Camundongos Endogâmicos BALB C , Nanopartículas/administração & dosagem , Nanopartículas/química , Toxina Shiga/administração & dosagem , Toxina Shiga/químicaRESUMO
PURPOSE: Radiation-induced oral mucositis is the most common side effect of radiotherapy in head and neck cancer; however, effective modalities for its prevention have not been established. In this study, we evaluated the effectiveness of Hangeshashinto (TJ-14), a Japanese herbal medicine, for preventing radiation-induced mucositis and elucidated its effect on inflammatory responses, including inflammatory cell chemotaxis and cyclooxygenase-2 (COX2) expression, in an animal model. METHODS: Syrian hamsters, 8-9 weeks old, were enrolled in this study. Animals were irradiated with a single 40 Gy dose to the buccal mucosa. Hamsters freely received a treatment diet mixed with 2% TJ-14 or a normal diet daily. The therapeutic effect was determined based on the visual mucositis score, body weight, and histological examination of infiltrated neutrophils and COX2 expression. RESULTS: TJ-14 significantly reduced the severity of mucositis. The percentage with severe mucositis (score ≥3) was 100% in the untreated group and 16.7% in the TJ-14 group (P < 0.05). There was no difference in body weight change between the groups; however, weight gain in the untreated group tended to be suppressed compared to that in the TJ-14 group during the peak period of mucositis. In addition, TJ-14 inhibited the infiltration of neutrophils and COX2 expression in irradiated mucosa (P < 0.05). CONCLUSIONS: TJ-14 reduced the severity of mucositis in an animal model by suppressing the inflammatory response. Because TJ-14 is inexpensive and its safety is established, it is a promising candidate for the standard treatment of radiation-induced mucositis in cancer patients.
Assuntos
Quimiotaxia/efeitos dos fármacos , Ciclo-Oxigenase 2/química , Medicamentos de Ervas Chinesas/uso terapêutico , Raios gama/efeitos adversos , Inflamação/tratamento farmacológico , Mucosite/tratamento farmacológico , Lesões Experimentais por Radiação/prevenção & controle , Animais , Células Cultivadas , Cricetinae , Modelos Animais de Doenças , Feminino , Inflamação/etiologia , Inflamação/patologia , Mesocricetus , Mucosa Bucal/metabolismo , Mucosa Bucal/patologia , Mucosa Bucal/efeitos da radiação , Mucosite/etiologia , Mucosite/patologiaRESUMO
Colloidal clay in water suspensions are known to exhibit a multitude of bulk phases depending on initial colloidal concentration and ionic strength, and examples of this include repulsive Wigner colloidal glasses at low ionic strength and attractive gels at higher ionic strength due to screened electrostatic forces by the electrolyte. From confocal Raman microscopy combined with elasticity measurements, we infer that clay trapped at quasi two-dimensional interfaces between oil and water also exhibit confined glass-like or gel-like states. The results can be important for the preparation of particles stabilized colloidal emulsions or colloidal capsules, and a better understanding of this phenomenon may lead to new emulsion or encapsulation technologies.
RESUMO
Conversion of Pomacea lineate shells into hydroxyapatite (HA) bioceramic materials was investigated by their in vitro treatment with phosphate solutions, at room temperature. Confocal Raman microscopy revealed that the conversion proceeds at distinct rates through the nacreous or periostracum sides of the shell. The conversion can be accelerated using powdered samples, yielding biocompatible materials of great interest in biomedicine.
Assuntos
Carbonato de Cálcio/metabolismo , Durapatita/metabolismo , Gastrópodes/química , Fosfatos/metabolismo , Animais , Gastrópodes/metabolismo , Microscopia Confocal , Microscopia Eletrônica , Análise Espectral RamanRESUMO
The cis-doubly N-confused porphyrin, H2N2CP, containing two adjacent confused pyrrole rings has been investigated from the point of view of its acid-base and electrochemical behavior in dichloromethane. This novel porphyrin isomer can form two metal-carbon bonds in the central core, stabilizing metal ions in unusually high oxidation states. Furthermore, the two outside N-pyrrole atoms remain available for acid-base and specific solvent interactions. Protonation of the pyrrole N atoms proceeds according to two successive steps, while only a single deprotonation step has been observed in the presence of bases. Similarly, in the case of the silver and copper complexes the protonation and deprotonation of the outer pyrrole rings have been detected, confirming the structure of the metalated species as M(III)-HN2CP. The electrochemical reduction of the metal ions (III/II redox process) and oxidation of the macrocycle ring have been detected respectively at -0.9 and 1.4 V based on spectroelectrochemical measurements in conjunction with the acid/base equilibrium studies. Additional waves observed around -0.5 and 1.3 V have been assigned to redox processes involving water molecules associated with the doubly N-confused porphyrins.
RESUMO
A relevant series of symmetric supramolecular porphyrins has been obtained by attaching four [RuII(bipy)2Cl] groups to the pyridyl substituents of meso-tetra(4-pyridyl)porphyrin and its metallated derivatives. These compounds display a rich electrochemistry and versatile catalytic, electrocatalytic and photochemical properties, associated with the ruthenium-bipyridine and the porphyrin complexes. These properties can be transferred to the electrodes by attaching thin molecular films of the compounds, by dip-coating, electrostatic assembly or electropolymerization. In this way, the interesting properties of those supermolecules and supramolecular assemblies can be used to prepare molecular devices and sensors.
Assuntos
Técnicas Biossensoriais/métodos , Porfirinas/química , Substâncias Macromoleculares , Espectrometria de Massas , Compostos de Rutênio/químicaRESUMO
The photooxidation of calf-thymus DNA has been investigated in the presence of a supramolecular tetraruthenated zincporphyrin (ZnTRP) sensitizer. A strong interaction of ZnTRP with DNA has been observed, exhibiting a gradual transition from a non-specific electrostatic binding mode to a more specific one at high DNA concentrations. Formation of O2(1delta(g)) has been detected from its near-infrared emission, after the excitation of ZnTRP in dioxygen-containing solutions. In the presence of DNA and dioxygen, ZnTRP promotes efficient photocatalytic oxidation of the 2'-deoxyguanosine sites, via their direct reaction with O2(1delta(g)), as in a previous work on the ZnTRP-photoinduced oxidation of the free nucleosides.
Assuntos
DNA/metabolismo , Compostos Organometálicos/metabolismo , Porfirinas/metabolismo , Timo/metabolismo , Zinco/metabolismo , Animais , Bovinos , Cromatografia Líquida de Alta Pressão , DNA/efeitos dos fármacos , DNA/efeitos da radiação , Relação Dose-Resposta a Droga , Cinética , Luz , Modelos Químicos , Oxigênio/metabolismo , Ligação Proteica , Espectrometria de Fluorescência , Fatores de TempoRESUMO
The mutagenic activity of bile was compared between Chilean and Japanese female patients having cholelithiasis by the Ames assay using Salmonella typhimurium tester strain TA98 in the presence of S9 mix with blue rayon adsorption technique. A reason for conducting the present investigation is that Chile and Japan have the highest mortality rates for the gallbladder cancer (GBC) in the world. Of 24 bile samples collected in Chile, 20 (83.3%) samples showed mutagenicity. In the case of Japanese bile, 21 (80.8%) of 26 and 5 (19.2%) of 26 cases were mutagenic in samples from high- and low-risk areas for GBC, respectively. Therefore, both the Chilean and the Japanese samples collected in high-risk areas showed higher mutagenic rates than the Japanese ones in a low-risk area, with a statistical significance (p < 0.001), chi-square test). The average number of revertant colonies were 128 +/- 92 (mean +/- SD), 62 +/- 14 and 66 +/- 13, respectively, when the blue rayon extracts of 200 microliters bile were applied to the Ames test. Thus, Chilean bile had a tendency to show a higher mutagenic activity than Japanese.
Assuntos
Bile/química , Colelitíase/etnologia , Mutagênicos/toxicidade , Adulto , Idoso , Animais , Biotransformação , Chile , Colelitíase/fisiopatologia , Feminino , Humanos , Japão , Pessoa de Meia-Idade , Mutagênicos/farmacocinética , RatosRESUMO
The aim of this investigation is the evaluation of DNA interaction of with tetraruthenated porphyrin (TRP) and of DNA damage in the presence of light. Direct-fluorescence and electronic absorption measurements after incubation of DNA with TRP indicate strong binding between pBR322 DNA or calf thymus DNA with the modified porphyrin. Exposure of pBR322 DNA to TRP (up to 3 microM) and light leads to single-strand break formation as determined by the conversion of the supercoiled form (form I) of the plasmid into the nicked circular form (form II). Oxidative DNA base damage was evaluated by the detection of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) after irradiation of calf thymus DNA in the presence of the TRP. The data demonstrated a dose and time dependence with each type of DNA damage. These data indicate (1) a specificity of the binding mode and (2) type I and II photoinduced mechanisms leading to strand scission activity and 8-oxodGuo formation. Accordingly, singlet molecular oxygen formation, after TRP excitation, was confirmed by near-infrared emission. From these investigations a potential application of TRP in photodynamic therapy is proposed.