Browsing by Author "Pereira, D."
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- Ceruloplasmin expression by human peripheral blood lymphocytes: a new link between immunity and iron metabolismPublication . Banha, J.; Marques, L.; Oliveira, R.; Martins, M. de F.; Paixão, E.; Pereira, D.; Malhó, R.; Penque, D.; Costa, L.Ceruloplasmin (CP) is a multicopper oxidase involved in the acute phase reaction to stress. Although the physiological role of CP is uncertain, its role in iron (Fe) homeostasis and protection against free radical-initiated cell injury has been widely documented. Previous studies showed the existence of two molecular isoforms of CP: secreted CP (sCP) and a membrane glycosylphosphatidylinositol (GPI)-anchored form of CP (GPI-CP). sCP is produced mainly by the liver and is abundant in human serum whereas GPI-CP is expressed in mammalian astrocytes, rat leptomeningeal cells, and Sertolli cells. Herein, we show using RT-PCR that human peripheral blood lymphocytes (huPBL) constitutively express the transcripts for both CP molecular isoforms previously reported. Also, expression of CP in huPBL is demonstrated by immunofluorescence with confocal microscopy and flow cytometry analysis using cells isolated from healthy blood donors with normal Fe status. Importantly, the results obtained show that natural killer cells have a significantly higher CP expression compared to all other major lymphocyte subsets. In this context, the involvement of lymphocyte-derived CP on host defense processes via its anti/prooxidant properties is proposed, giving further support for a close functional interaction between the immune system and the Fe metabolism.
- Characterization of chitosan meant for antimicrobial food packagingPublication . Sendón, R.; Rodríguez Bernaldo de Quirós, A.; Bueno, C.; Pereira, D.; Sanches-Silva, A.; Costa, H.S.; Sánchez-Machado, D.I.; Soto Valdez, H.; Angulo, I.; Aurrekoetxea, G.P.; López-Cervantes, J.; Paseiro, P.Chitosan (CAS nº 9012-76-4) is a natural polysaccharide obtained by the partial deacetylation of chitin. It is a linear polymer of β (1-4) 2-acetamido-2-deoxy-D-glucose and 2-amino-2-deoxy-D-glucose in different proportions. Chitin is the most abundant polysaccharide after cellulose and the main source is the shells of crustaceans. It has been demonstrated that some important properties are directly related to the antimicrobial activity of chitosan. Some of these properties are the molecular weight (Mw), the degree of polymerisation (DP) and the degree of deacetylation (DD). In this work several analytical techniques (FTIR (Fourier-transform Infrared Spectroscopy), NMR (Nuclear Magnetic Resonance Spectroscopy) and SEM (Scanning Electron Microscopy)) were attempted to characterize two different samples obtained from shrimp waste. It can be concluded that sample 1 should be more suitable to be added as an active agent to a film.
- Crosstalk between inflammation, iron metabolism and endothelial function in Behçet’s diseasePublication . Oliveira, R.; Napoleão, P.; Banha, J.; Paixão, E.; Bettencourt, A.; M da Silva, B.; Pereira, D.; Barcelos, F.; Teixeira, A.; Vaz Patto, J.; Viegas-Crespo, A.M.; Costa, L.Behçet's disease (BD) is a rare chronic vasculitis of unclear etiology. It has been suggested that inflammatory response has an important role in BD pathophysiology. Herein, we aimed to study the interplay between inflammation, iron metabolism and endothelial function in BD and search for its putative association with disease activity. Twenty five patients clinically diagnosed with BD were selected and twenty four healthy age-sex matched individuals participated as controls. Results showed an increase of total number of circulating white blood cells and neutrophils, serum transferrin, total iron binding capacity, mieloperoxidase (MPO), ceruloplasmin (Cp), C reactive protein, β2 microglobulin and Cp surface expression in peripheral blood monocytes in BD patients comparatively to healthy individuals (p < 0,05). Of notice, the alterations observed were associated to disease activity status. No significant differences between the two groups were found in serum nitric oxide concentration. The results obtained suggest an important contribution from innate immunity in the pathogenesis of this disease. In particular, surface expression of leukocyte-derived Cp may constitute a new and relevant biomarker to understand BD etiology.
- Lymphocyte ceruloplasmin and Behçet's diseasePublication . Oliveira, R.; Banha, J.; Martins, F.; Paixão, E.; Pereira, D.; Barcelos, F.; Teixeira, A.; Patto, J.V.; Costa, L.Behçet's disease (BD) is a rare chronic inflammatory disorder of unknown aetiology. However, it has been postulated that a dysregulation of the prooxidant/antioxidant balance may be important to its pathogenesis. Ceruloplasmin (CP) is an acute phase protein expressed at the surface of peripheral blood lymphocytes (PBL) with antioxidant properties and with a relevant role in iron (Fe) metabolism.