An alternative hybrid lipid nanosystem combining cytotoxic and magnetic properties as a tool to potentiate antitumor effect of 5-fluorouracil.

AIMS: Colorectal cancer is the third most frequent type of cancer and the second leading cause of cancer-related deaths worldwide. The majority of cases are diagnosed at a later stage, leading to the need for more aggressive treatments such as chemotherapy. 5-Fluorouracil (5-FU), known for its high cytotoxic properties has emerged as a chemotherapeutic agent. However, it presents several drawbacks such as lack of specificity and short half-life. To reduce these drawbacks, several strategies have been designed namely chemical modification or association to drug delivery systems. MATERIALS AND METHODS: Current research was focused on the design, physicochemical characterization and in vitro evaluation of a lipid-based system loaded with 5-FU. Furthermore, aiming to maximize preferential targeting and release at tumour sites, a hybrid lipid-based system, combining both therapeutic and magnetic properties was developed and validated. For this purpose, liposomes co-loaded with 5-FU and iron oxide (II, III) nanoparticles were accomplished. KEY FINDINGS: The characterization of the developed nanoformulation was performed in terms of incorporation parameters, mean size and surface charge. In vitro studies assessed in a murine colon cancer cell line confirmed that 5-FU antiproliferative activity was preserved after incorporation in liposomes. In same model, iron oxide (II, III) nanoparticles did not exhibit cytotoxic properties. Additionally, the presence of these nanoparticles was shown to confer magnetic properties to the liposomes, allowing them to respond to external magnetic fields. SIGNIFICANCE: Overall, a lipid nanosystem loading a chemotherapeutic agent displaying magnetic characteristics was successfully designed and physicochemically characterized, for further in vivo applications.

Genetic and taxonomical aspects of Biomphalaria glabrata ABO agglutinins

Foram realizadas titulaçöes de posturas dos dois genótipos pigmentários, albinos totais e pigmentados, de caramujos Biomphalaria glabrata. Ambas as cepas reagiram negativamente com hemácias O normais e nenhuma hemolisina foi detectada. Ambos os genótipos de Santa Luzia (Minas Gerais) tinham similares títulos médios frente a eritrócitos A1, A2 e B normais e nenhuma diferença foi observada entre os genótipos em relaçäo com cada um dos grupos sanguíneos ABO. O padräo sorológico da linhagem albino de Porecatú (Paraná) é similar `aquela de Santa Luzia, mais mostra títulos mais baixos. Por outro lado, os dois genótipos de Rio Capibaribe (Pernambuco) mostraram diferenças significantes e um gradiente marcante nos seus títulos médios frente a hemácias dos diversos grupos ABO. Os caramujos albinos desta localidade näo apresentam atividade anti-B. A ausência de anti-B foi significantemente associada com o genótipo albino da amostra em conjunto (Método exato de Fisher, p = 0,0058). A aglutinina anti-A de esta cepa deu reaçöes semelhantes com a lectina anti-A hel contra um antígeno A fraco de um doador de grupo AB Negroide Brasileiro. Absorçöes seletivas de extratos de caramujos pigmentados permitiram separar aglutininas salinas anti-A e anti-B e aglutininas incompletas anti-A, anti-A,B e anti-O. Títulos mais elevados, em geral, foram obtidos através do uso de células tratadas com enzimas. A açäo da neuraminidase näo segue a tendências de outras enzimas desde que ela näo altera os títulos com as células A1, B e O. As posturas das três espécies do género Biomphalaria, hospedeiro intermediário da Schistossomose mansoni, poderiam ser distinguidas pela presença ou ausência dos seguintes critérios: 1) Aglutinaçäo...