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Browsing by Issue Date, starting with "2010-10-16"

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  • Anti-Candida activity of a chitosan hydrogel: mechanism of action and cytotoxicity profile
    Publication . Oliveira, Ana Palmeira de; Ribeiro, MP.; Oliveira, Rita Manuela Palmeira de; Gaspar, Carlos; Oliveira, Sofia Costa de; Correia, I.J.; Vaz, Cidália Pina; Oliveira, José António Martinez Souto de; Queiroz, João; Rodrigues, Acácio
    Candida spp. are common causative agents of mucocutaneous infections. New therapeutic antifungal drugs are needed to treat chronic disease as these are frequently clinically resistant to azols. Chitosan, among other possible vehicles for active compounds, shows an added value as it appears to have intrinsic antimicrobial properties. The aim of the present study was to evaluate the anti-Candida activity of a medium-molecular-weight chitosan hydrogel (CH), to clarify its possible mechanism of action and to evaluate its cytotoxicity on human fibroblasts. CH antifungal activity was assessed according to CLSI reference M27-A3 protocol; its mechanism of action was investigated by flow cytometry, and its cytotoxicity was studied by MTT assay. CH demonstrated a full inhibition of C. tropicalis, C. krusei, C. guilliermondii and C. parapsilosis growth while impairing C. albicans and C. glabrata viability. Flow cytometry tests showed that CH acts by inducing primary lesion of the cytoplasmic membrane. However, CH showed no cytotoxic effect upon human fibroblasts cells. Resistant strains will require new therapeutic approaches. Chitosan being a good carrier and having itself anti-Candida activity seems to be a promising vehicle to be used for the treatment of mucocutaneous candidosis.
    2010-10-16Journal article Restricted access Show more
  • Preparation and chemical and biological characterization of a pectin/chitosan polyelectrolyte complex scaffold for possible bone tissue engineering applications
    Publication . Coimbra, Patrícia; Ferreira, Paula; Sousa, Hermínio C. de; Batista, Patrícia Sofia Pinhanços; Rodrigues, Miguel; Correia, Ilídio Joaquim Sobreira; Gil, Maria
    In this work, porous scaffolds obtained from the freeze-drying of pectin/chitosan polyelectrolyte complexes were prepared and characterized by FTIR, SEM and weight loss studies. Additionally, the cytotoxicity of the prepared scaffolds was evaluated in vitro, using human osteoblast cells. The results obtained showed that cells adhered to scaffolds and proliferated. The study also confirmed that the degradation by-products of pectin/chitosan scaffold are noncytotoxic.
    2010-10-16Journal article Restricted access Show more