Encontrados 17 documentos, a visualizar página 1 de 2
Biomimetic sensor based on hemin/carbon nanotubes/chitosan modified microelectr...
Santos, Ricardo M.; Rodrigues, Marcelo S.; Laranjinha, João; Barbosa, Rui M.A novel biomimetic microsensor for measuring nitric oxide (NO) in the brain in vivo was developed. The sensor consists of hemin and functionalized multi-wall carbon nanotubes covalently attached to chitosan via the carbodiimide crosslinker EDC followed by chitosan electrodeposition on the surface of carbon fiber microelectrodes. Cyclic voltammetry supported direct electron transfer from the FeIII/FeII couple of...
3,4-Dihydroxyphenylacetic acid (DOPAC) modulates the toxicity induced by nitric...
Nunes, Carla; Almeida, Leonor; Laranjinha, Joãohttp://www.sciencedirect.com/science/article/B6W81-4T3DCPW-1/2/1471e87c319c0cc405a12b700ec15c89
The potent vasodilator ethyl nitrite is formed upon reaction of nitrite and eth...
Gago, Bruno; Nyström, Thomas; Cavaleiro, Carlos; Rocha, Bárbara S.; Barbosa, Rui M.; Laranjinha, João; Lundberg, Jon O.By acting as a bioreactor, affording chemical and mechanical conditions for the reaction between dietary components, the stomach may be a source of new bioactive molecules. Using gas chromatography-mass spectrometry we here demonstrate that, under acidic gastric conditions, ethyl nitrite is formed in µM concentrations from the reaction of red wine or distilled alcoholic drinks with physiological amounts of nitr...
Diphenyl diselenide, a simple glutathione peroxidase mimetic, inhibits human LD...
Bem, Andreza Fabro de; Farina, Marcelo; Portella, Rafael de Lima; Nogueira, Cristina Wayne; Dinis, Teresa C. P.; Laranjinha, João A. N.Oxidative modification of low-density lipoprotein (LDL) represents an important factor in atherogenesis. In the present study, we have investigated the antioxidant capability of diphenyl diselenide (PhSe)2, a simple organoseleno compound, against copper (Cu2+) and peroxyl radical-induced human LDL oxidation in vitro. In initial studies using human serum, (PhSe)2 caused a dose-dependent inhibition of Cu2+-induce...
LDL Isolated from Plasma-Loaded Red Wine Procyanidins Resist Lipid Oxidation an...
Lourenço, Cátia F.; Gago, Bruno; Barbosa, Rui M.; Freitas, Víctor de; Laranjinha, JoãoDietary phenolic compounds may act as antioxidants in vitro, but because of structural modifications during absorption, its role based on concentrations high enough to afford an antioxidant protection needs to be re-evaluated. We have explored the hypothesis that red wine procyanidins interact with low density lipoproteins (LDL) and that, at this location, the phenolic compounds efficiently protect LDL from oxi...
Red wine-dependent reduction of nitrite to nitric oxide in the stomach
Gago, Bruno; Lundberg, Jon O.; Barbosa, Rui M.; Laranjinha, JoãoNitrite may be a source for nitric oxide (NO), particularly in highly acidic environments, such as the stomach. Diet products contribute also with reductants that dramatically increase the production of NO from nitrite. Red wine has been attributed health promoting properties largely on basis of the reductive antioxidant properties of its polyphenolic fraction. We show in vitro that wine, wine anthocyanin fract...
Electrochemical measurement of endogenously produced nitric oxide in brain slic...
Ferreira, Nuno R.; Ledo, Ana; Frade, João G.; Gerhardt, Greg A.; Laranjinha, João; Barbosa, Rui M.The role of nitric oxide (NO) as a regulatory diffusible molecule in the brain requires the evaluation of its concentration dynamics. In this work, we have developed microelectrodes suitable for real time electrochemical measurements of NO in vitro. Nafion and o-phenylenediamine were used to modify the surface of carbon fiber microelectrodes (8 [mu]m diameter; [approximate]100 [mu]m tip length). Coating with Na...
Redox interactions of nitric oxide with dopamine and its derivatives
Antunes, Fernando; Nunes, Carla; Laranjinha, João; Cadenas, EnriqueNitric oxide (NO) is a ubiquitous diffusible messenger in the central nervous system. NO and derived nitrogen species may interact with catecholamines, thus, modifying not only its regulatory actions but also producing oxidants and free radicals that are likely to trigger toxic pathways in the nervous system. Oxidative pathways and chain oxidation reactions triggered by catecholamines may be broken by ascorbate...
Concentration Dynamics of Nitric Oxide in Rat Hippocampal Slices
Ledo, Ana; Barbosa, Rui M.; Cadenas, Enrique; Gerhardt, Greg; Laranjinha, JoãoNitric oxide () production in response to stimulation of the NMDA glutamate receptor is implicated not only in the synaptic plasticity in hippocampus but may also participate in excitotoxic cell death. Using -selective microssensors inserted into the diffusional field of in acute hippocampal slices, we describe the concentration dynamics evoked by NMDA receptor activation and report profound differences along...
Concentration dynamics of nitric oxide in rat hippocampal subregions evoked by ...
Ledo, Ana; Barbosa, Rui M.; Gerhardt, Greg A.; Cadenas, Enrique; Laranjinha, JoãoNitric oxide (*NO) production in response to stimulation of the NMDA glutamate receptor is implicated not only in the synaptic plasticity in hippocampus but may also participate in excitotoxic cell death. Using *NO-selective microssensors inserted into the diffusional field of *NO in acute hippocampal slices, we describe the *NO concentration dynamics evoked by NMDA receptor activation and report profound diffe...
| Financiadores do RCAAP | |||||||
|
|
|
|
|
|
||