Sulfated fucan from marine alga inhibits HeLa cells infection by HTLV-1 free particles: semi-quantitative analysis

A sulfated fucan from Laminaria abyssalis marine alga prevented the interaction of HTLV-1 particles, purified from the MT-2 cell line, with HeLa cells. The infection obtained using a concentrated virus suspension was detected only by amplification of the newly synthesized HTLV-1 proviral cDNA by the nested-polymerase chain reaction (PCR). The sulfated polysaccharide was not toxic to the cells at a concentration of 100 µg/mL and prevented infection by the viral particles when added to the cell monolayers. The proviral cDNA was only detected when the sulfated polysaccharide was added to the cells three hours post-infection, indicating that the inhibitory activity occurred in the initial stages of virus-cell interaction. Our results demonstrate, for the first time, the ability of a sulfated fucan from marine algae to inhibit virus transmission through free virus particles.

Efeito citotóxico de alginatos odontológicos sobre células fibroblastóides / Cytotoxic effects of a dentstry alginates applied on fibroblast-like cells

O alginato ou hidrocolóide irreversível é um dos materiais de moldagem mais aceitos e utilizados na Odontologia. Algumas substâncias presentes nesses pode levar toxicidade. O estuto foi avaliar a citotoxicidade de alginatos de uso odontológico. Foram avaliados quatro diferentes alginatos divididos em 4 grupos, assim denominados: Ava Gel, New Print, Kromopan e Hydrogum. Três grupos controle também participaram Controle positivo (C+) constituido pelo detergente celular Tween 80, controle negativo (C-) PBS, e controle de célula (CC) onde as células não foram expostas a nenhum material. Após manipulação dos materiais seguindo as orientações do fabricante foi confeccionado corpos de prova utilizando-se anéis de silicone. Em seguida os mesmos foram imersos em meio mínimo essencial de Eagle (MEM) por 2 min, onde então procedeu-se a remoção do sobrenadante e colocação em contato com fibroblastos L929. Após contato com o meio as células foram incubadas por mais 24 h onde então foram adicionados 100ml do corante vermelho neutro a 0,01%. Novamente as células foram incubadas por 3 h para que as mesmas incorporassem o corante. Passado esse período as mesmas foram fixadas e então, realizada contagem de células viáveis em espectrofotômetro (BioTek, Winooski, Vermont, USA) em um comprimento de onda de 492nm. Os resultados demonstraram diferenças estatísticas entre os grupos CC e C-com os demais (P<0.05). Ausência de diferença estatística ocorreu entre os grupos Ava Gel, New Print, Kromopan e Hydrogum (P>0.05). Pode-se concluir com a realização desse trabalho que todos os alginatos testados mostraram caráter citotoxico.

Alginate or irreversible hydrocolloid is one of the most accepted and used impression materials in dentstry. Some substances present in these can lead toxicity. The aim of this study was to evaluate the cytotoxicity of dental alginate of use. Was evaluated four different alginate divided into 4 groups, so called: Ava Gel, New Print, Kromopan e Hydrogum. Three control groups were also included: Group C+ (positive control), consisting of detergent Tween 80; Group C -(negative control), consisting of PBS, and Group CC (cell control), consisting of cells not exposed to any material. After manipulating the materials according to the manufacturer's instructions, samples were made by using silicon rings. Next, the samples were immersed into Eagle minimum essential medium (MEM) for 2 minutes, where the supernatants were removed and brought into direct contact with L929 fibroblasts. Following exposure to the medium, the cells were incubated for further 24 hours and then 100 ml of 0.01% neutral red dye were added. The cells were incubated again for 3 hours so that the dye could be absorbed. After this 3-hour period, the cells were fixed in order to count the viable ones by using a spectrophotometer (BioTek, Winooski, Vermont, USA) at a wavelength of 492nm. The results showed statistical differences between groups CC and C- with the others (P <0.05). Lack of statistical difference occurred between groups and between Ava Gel, New Print, Kromopan e Hydrogum (P> 0.05). Based on the results obtained in this work, one can conclude that all four alginate impression materials are potentially cytotoxic.