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| MUÑOZ,PABLO; ZAVALA,GABRIELA; CASTILLO,KAREN; AGUIRRE,PABLA; HIDALGO,CECILIA; NÚÑEZ,MARCO T. |
| Recent evidence suggests that reactive oxygen species function as second messenger molecules in normal physiological processes. For example, activation of N-Methyl-D-Aspartate receptor results in the production of ROS, which appears to be critical for synaptic plasticity, one of the cellular mechanisms that underlie learning and memory. In this work, we studied the effect of iron in the activation of MAPK/ERK pathway and on Ca2+ signaling in neuronal PC12 cells. We found that iron-dependent generation of hydroxyl radicals is likely to modulate Ca2+ signaling through RyR calcium channel activation, which, in turn, activates the MAPK/ERK pathway. These findings underline the relevance of iron in normal neuronal function. |
| Tipo: Journal article |
Palavras-chave: NMDA receptor; Calcium; Iron; Oxidative stress; MAPK/ERK; Hippocampal slices; Long-term potentiation. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000100021 |
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| MENA,NATALIA P; ESPARZA,ANDRÉS L; NÚÑEZ,MARCO T. |
| Hepcidin (Hepc) is a 25 amino acid cationic peptide with broad antibacterial and antifungal actions. A likely role for Hepc in iron metabolism was suggested by the observation that mice having disruption of the gene encoding the transcription factor USF2 failed to produce Hepc mRNA and developed spontaneous visceral iron overload. Lately, Hepc has been considered the "stores regulator," a putative factor that signals the iron content of the body to intestinal cells. In this work, we characterized the effect of Hepc produced by hepatoma cells on iron absorption by intestinal cells. To that end, human Hepc cDNA was cloned and overexpressed in HepG2 cells and conditioned media from Hepc-overexpressing cells was used to study the effects of Hepc on intestinal... |
| Tipo: Journal article |
Palavras-chave: Hepcidin; Iron absorption; DMT1; Caco-2 cells. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000100022 |
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| ARREDONDO,MIGUEL; MARTÍNEZ,RONNY; NÚÑEZ,MARCO T; RUZ,MANUEL; OLIVARES,MANUEL. |
| Interactions of micronutrients can affect absorption and bioavailability of other nutrients by a number of mechanisms. In aqueous solutions, and at higher uptake levels, competition between elements with similar chemical characteristics and uptake process can take place. The consequences of these interactions may depend on the relative concentrations of the nutrients. In this work, we measure the effects of increasing concentrations of iron, zinc, and copper on iron and copper uptake in Caco-2 cells. Intracellular Fe or Cu levels were affected by incubating with increased concentrations of metals. However, when the cells already had different intracellular metal concentration, the uptake of Fe or Cu was nor affected. In competition studies, we showed that... |
| Tipo: Journal article |
Palavras-chave: Competition; Interaction; Metals; Uptake. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000100011 |
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| EZQUER,FERNANDO; NÚÑEZ,MARCO T; ROJAS,ALEJANDRO; ASENJO,JUAN; ISRAEL,YEDY. |
| Levels of body iron should be tightly controlled to prevent the formation of oxygen radicals, lipoperoxidation, genotoxicity, and the production of cytotoxic cytokines, which result in damage to a number of organs. Enterocytes in the intestinal villae are involved in the apical uptake of iron from the intestinal lumen; iron is further exported from the cells into the circulation. The apical divalent metal transporter-1 (DMT1) transports ferrous iron from the lumen into the cells, while the basolateral transporter ferroportin extrudes iron from the enterocytes into the circulation. Patients with hereditary hemochromatosis display an accelerated transepithelial uptake of iron, which leads to body iron accumulation that results in cirrhosis, hepatocellular... |
| Tipo: Journal article |
Palavras-chave: Iron; Intestine; Hemochromatosis; Gene therapy; HFE; DMT1; Cirrhosis. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000100014 |
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