Gold nanorods induce early embryonic developmental delay and lethality in zebrafish (Danio rerio)

Due to their unique electronic and optical features, gold nanoparticles (AuNP) have received a great deal of attention for application in different fields such as catalysis, electronics, and biomedicine. The large-volume manufacturing predicted for future decades and the inevitable release of these substances into the environment necessitated an assessment of potential adverse human and ecological risks due to exposure to AuNP. Accordingly, this study aimed to examine the acute and developmental toxicity attributed to a commercial suspension of Au nanorods stabilized with cetyltrimethylammonium bromide (CTAB-AuNR) using early embryonic stages of zebrafish (Danio rerio), a well-established model in ecotoxicology. Zebrafish embryos were exposed to CTAB-AuNR (0–150 µg/L) to determine for developmental assessment until 96 hr post fertilization (hpf) and lethality. Uptake of CTAB-AuNR by embryos and nanoparticles potential to induce DNA damage was also measured at 48 and 96 hpf. Analysis of the concentration-response curves with cumulative mortality at 96 hpf revealed a median lethal concentration (LC50,96h) of 110.2 μg/L. At sublethal concentrations, CTAB-AuNR suspensions were found to produce developmental abnormalities such as tail deformities, pericardial edema, decreased body length, and delayed eye, head, and tail elongation development. Further, less than 1% of the initial concentration of CTAB-AuNR present in the exposure media was internalized by zebrafish embryos prior to (48 hpf) and after hatching (96 hpf). In addition, no marked DNA damage was detected in embryos after exposure to CTAB-AuNR. Overall, CTAB-AuNR suspensions produced lethal and sublethal effects on zebrafish embryos with possible repercussions in fitness of adult stages. However, these results foresee a low risk for fish since the observed effects occurred at concentrations above the levels expected to find in the aquatic environment.This work was supported by FEDER funds through the program COMPETE—Programa Operacional Factores de Competitividade,” and by the Portuguese Foundation for Science and Technology (FCT), within the CESAM’s strategic program (UID/AMB/50017/2013), the research project Synchrony (PTDC/AAG-MAA/2140/2012). This research was also partially supported by FCT and the European Regional Development Fund (ERDF), in the framework of the program PT2020 and of ERA-NET SIINN through project NanoToxClass (ERA-SIINN/0001/2013). The materials characterization performed was also developed in the scope of the project CICECO—Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (Ref. FCT UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when applicable co-financed by FEDER under the PT2020 Partnership Agreement, and also the project MAGICOAT (PTDC/CTM-BIO/2170/2014). JT thanks FCT for the research grant IF/00347/2013

Surface studies on acrylic bone cement

Poly(methyl methacrylate) (PMMA) is used to fill the gap between the prosthesis and the surrounding bone in cemented arthroplasties. Biocompatibility problems related to bone cement application limit the clinical success of these cemented arthroplasties. Being the cement surface in close connection with the living bone, it is reasonable to assume that surface properties such as, surface composition and surface energy, will play a role in the biomaterial performance. X-ray photoelectron spectroscopy (XPS) analysis and surface energy studies were carried out during 4 months, in order to assess a possible correlation between aging time and surface changes. The aging of PMMA, in a biological model fluid, strongly influences the composition and wettability of the cement surface. These changes may be explained through the hydrolysis of PMMA ester groups and the subsequent hydrogen bonding. Although our study does not exactly reproduce the in vivo environment surrounding a prosthesis, it suggests that the changes in the composition and wettability of the surface may modulate the host response towards the implant, thus contributing to its loosening. (C) 2004 Elsevier B.V. All rights reserved

The effect of ethanol on acrylic bone cement

Prosthesis loosening is a major problem associated with the use of poly(methyl methacrylate) (PMMA) bone cement that may be related to a peri-implant vacuolisation commonly observed at bone-cement interface. Methyl methacrylate (MMA) monomer may be one of the cement components partly responsible for the mentioned vacuolisation due to a cytotoxic effect associated to this compound. Alcoholism has been related to bone necrosis in predisposed individuals. Furthermore, ethanol has been shown to clean material with adherent cement debris during cleaning procedure in laboratory. Consequently, we have decided to study whether ethanol will also be related to an increased liberation of MMA from the polymer matrix. 'In vitro' release studies using PMMA plates were conducted to access the role of ethanol on the liberation of the monomer. Contact angle measurements and surface tension estimation were also carried out in order to find a possible effect of ethanol on surface cement properties. Results suggest that ethanol, even in small quantities, enhances the leaching of the monomer from the polymer matrix, but does not considerably change the wettability properties of the cement surface. (C) 2002 Elsevier Science B.V. All rights reserved

Música e Identidade: relatos de autobiografias musicais em pacientes com esclerose múltipla Music and identity: musical autobiographies in multiple sclerosis patients

Autobiografias musicais constituem um recurso terapêutico eloqüente a respeito de como os indivíduos definem a si mesmos, auxiliando a (re)construção da identidade e contribuindo para a melhoria da qualidade de vida de portadores de Esclerose Múltipla. Oito pacientes adultos sob acompanhamento no Centro de Investigação em Esclerose Múltipla (CIEM) - UFMG, selecionaram entre 10 a 15 músicas significativas em sua vida, a respeito das quais discorreram em entrevista aberta. Os dados foram analisados qualitativamente segundo categorias criadas pelo musicoterapeuta norueguês Even RUDD (1998), que visam revelar como o indivíduo expressa suas identidades pessoal, social, temporal e transpessoal. Submetidos a tratamento quantitativo, os dados indicaram que, através da sua história musical, os pacientes aumentaram a percepção dos sentimentos e sensações corporais, expressaram-se de maneiras alternativas e ativaram memórias afetivas, contextualizando-as e adquirindo um senso de continuidade da vida.<br>Musical autobiographies consist a powerful therapeutic tool through which individuals define themselves, helping in the (re)construction of their identities and in enhancing quality of life of Multiple Sclerosis patients. Eight adult patients under treatment in the Research Centre for Multiple Sclerosis (CIEM) - UFMG, selected 10 to 15 significant pieces of music in their lives, after which they narrated in open interview. The data collected were submitted to the music therapist Even RUDD (1998) categories, which reveal how the person expresses his personal, social, temporal and transpersonal identities. The quantitative treatment indicate that, through their musical history, patients could better the perception of their feelings and body awareness, they could express themselves through alternative ways and activated affective memories, contextualizing them and achieving a sense of continuity of life