Browsing by Author "Castro, Matilde F."
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- Biodegradation of acrylic based resins: a reviewPublication . Bettencourt, Ana F.; Neves, Cristina B.; Almeida, Marise S. de; Pinheiro, Lídia M.; Oliveira, Sofia Arantes e; Lopes, Luís P.; Castro, Matilde F.Objectives. The development of different types of materials with application in dentistry is an area of intense growth and research, due to its importance in oral health. Among the different materials there are the acrylic based resins that have been extensively used either in restorations or in dentures. The objective of this manuscript was to review the acrylic based resins biodegradation phenomena. Specific attention was given to the causes and consequences of materials degradation under the oral environment. Data and sources. Information from scientific full papers, reviews or abstracts published from 1963 to datewere included in the review. Published materialwas searched in dental literature using general and specialist databases, like the PubMED database. Study selection. Published studies regarding the description of biodegradation mechanisms, in vitro and in vivo release experiments and cell based studies conducted on acrylic based resins or their components were evaluated. Studies related to the effect of biodegradation on the physical and mechanical properties of the materials were also analyzed. Conclusions. Different factors such as saliva characteristics, chewing or thermal and chemical dietary changes may be responsible for the biodegradation of acrylic based resins. Release of potential toxic compounds from the material and change on their physical and mechanical properties are the major consequences of biodegradation. Increasing concern arises from potential toxic effects of biodegradation products under clinical application thus justifying an intensive research in this área.
- Contents of conjugated linoleic acid isomers in ruminant-derived foods and estimation of their contribution to daily intake in PortugalPublication . Martins, Susana V.; Lopes, Paula A.; Alfaia, Cristina M.; Ribeiro, Veronica S.; Guerreiro, Teresa V.; Fontes, Carlos M. G. A.; Castro, Matilde F.; Soveral, Graca; Prates, Jose A. M.The present study provides a detailed overview of the contents of conjugated linoleic acid (CLA) isomers in the most consumed Portuguese CLA-rich foods (milk, butter, yoghurt, cheese, beef and lamb meat), by using silver ion-HPLC. In addition, the contribution of these ruminant-derived foods to the daily intake of CLA isomers was estimated based on Portuguese consumption habits. The total CLA concentration in milk and dairy products ranged from 4.00 mg/g fat in yoghurt to 7.22 mg/g fat in butter, and, regarding meats, from 4-45 mg/g fat in intensively produced beef to 11.29 mg/g fat in lamb meat. The predominant CLA isomers identified in these products were cis-9,trans-11 (59.89-79.21 %) and trans-7,cis-9 (8.04-20.20%). The average estimated total CLA intake for the Portuguese population was 73.70mg/d. Milk and cheese are probably the two products with the highest contribution to the final CLA intake, as a result of their high fat content and consumption values. The results also suggested that cis-9,trans-11 and trans-7,cis-9 are the isomers most represented, with, respectively, 76.10 and 12.56 % of the total CLA intake. Being the first detailed report on the contents of total and individual CLA isomers in Portuguese commercial ruminant-derived foods, we further discuss the implication of the results for diet characteristics and human health.
- Diet supplementation with the cis-9,trans-11 conjugated linoleic acid isomer affects the size of adipocytes in Wistar ratsPublication . Lopes, Paula A.; Martins, Susana V.; Pinho, Mario S.; Alfaia, Cristina M.; Fontes, Carlos M. G. A.; Rodrigues, Pedro O.; Morais, Graqa S. L.; Castro, Matilde F.; Pinto, Rui; Prates, Jose A. M.Previous reports have demonstrated that conjugated linoleic acid (CLA) acts on body fat accumulation in a variety of animal models. The aim of the present study was to investigate the effect of cis (c)-9,trans (t)-11 and t10,c12 CLA isomers on the number and size of adipocytes from the inguinal and retroperitoneal fats in Wistar male rats. A 5.1% palm oil-based diet was supplemented with CLA isomers as follows: 0.6% of c9,t11, 0.6% of t10,c12, 1.3% of c9,t11 and t10,c12 isomers in mixture, and a control nonsupplemented group for comparative purposes. Fat tissues were prepared on microscope slides for histologic examination using an image-analysis software to count the number of adipocytes and measure cell sizes. The results showed that CLA isomers did not affect (P .05) either final body and fat depot weights or serum lipids (with the exception of triacylglycerols) and adipocytokines (leptin and adiponectin). Animals fed the c9, t11 CLA isomer diet showed larger adipocytes when compared to other groups. Independently of the CLA dietary treatment, retroperitoneal fat showed larger adipocytes (3319 mu m(2)) and therefore a smaller number of adipocytes per unit of area, compared to inguinal fat (3055 mu m(2)) Taken together, the data suggest that a palm oil-based diet supplemented with the c9,t11 CLA isomer in Wistar rats, in contrast to the t10,c12 isomer and the mixture of both isomers, increases adipocyte dimensions in inguinal and retroperitoneal fat depots, while having a minor effect in serum lipids and adipocytokines. (c) 2008 Elsevier Inc. All rights reserved.