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Levofloxacin is a synthetic broad-spectrum antibacterial agent for oral or intravenous administration. Chemically, levofloxacin is the levorotatory isomer (L-isomer) of racemate ofloxacin, a fluoroquinolone antibacterial agent. Quinolone derivatives rapidly and specifically inhibit the synthesis of bacterial DNA. Levofloxacin has in vitro activity against a broad range of aerobic and anaerobic Gram-positive and Gram-negative bacteria. However, formulation of combined poloxamers thermoregulated (as Pluronic® F127) and levofloxacin for use in multiresistant bacterial treatment were poorly described in the current literature. Thus, the aim of the present work is to characterize poloxamers for levofloxacin controlled release and their use in the treatment of multidrug bacterial resistance. Micelles were produced in colloidal dispersions, with a diameter between 5 and 100 nm, which form spontaneously from amphiphilic molecules under certain conditions as concentration and temperature. Encapsulation of levofloxacin into nanospheres showed efficiency and enhancement of antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae when compared with only levofloxacin. Furthermore, all formulations were not cytotoxic for NIH/3T3 cell lineage. In conclusion, poloxamers combined with levofloxacin have shown promising results, better than alone, decreasing the minimal inhibitory concentration of the studied bacterial multiresistance strains. In the future, this new formulation will be used after being tested in animal models in patients with resistant bacterial strains.

In this work, we investigated the effects of the proteic aggregated polymer of magnesium ammonium phospholi-noleate-palmitoleate anhydride (MAPA) isolated from Aspergillus oryzae on the growth and differentiation ofbone marrow granulocyte-macrophage progenitor cells (CFU-GM) inListeriamonocytogenes-infectedmice.Asignificant reduction in the CFU-GM numberwas observed in the initial phase of infection with a sublethal dose of Listeria. Treatment of mice with 0.5, 2.0 and 5.0 mg/kg MAPA for 7 days prior to infection significantly stimulated myelopoiesis in a dose-dependent manner. Moreover, treatment with 0.5 and 5.0 mg/kg MAPA resulted in 30%/6 and 40% cures of mice lethally infected with Listeria, respectively. MAPA added directly to the culture dishes hardly affected colony formation by bone marrow cells, suggesting an indirect effect ofthis compound on myelopoiesis in vivo. In summary, the data show that MAPA can modulate the CFU-GM generation and antibacterial resistance in listeriosis. As the ability of hematopoietic tissues to produce phagocytes is of particular significance to mediate resistance to Listeria, the promotion ofbone marrow CFU-GM by MAPA may contribute to a rapid restoration of phagocyte numbers in infected sites, thus mitigating the course of infection.

Filmes de poli(estireno) (PS), poli(metacrilato de metila) (PMMA), blenda de PS/PMMA (1:1) e copolímero PS-b-PMMA foram preparados e avaliados quanto à adesão celular usando fibroblastos de camundongos L929. Embora todos os filmes poliméricos tenham se mostrado bons substratos para o crescimento e proliferação celular, estes processos foram levemente favorecidos na blenda PS:PMMA. O número e a morfologia foram idênticos para cultura de células nos filmes e na lamínula de vidro ou na placa de plástico. A característica química dos filmes poliméricos é adequada para suportar o ataque e proliferação das células, sugerindo que esses filmes são bons candidatos para usos biomédicos.Films of pure poly(styrene) (PS), pure poly(methyl methacrylate) (PMMA), a 1:1 PS/PMMA blend and a PS-b-PMMA copolymer, were prepared and tested for cell adhesion using L929 mouse fibroblasts. All polymer films were found to be good substrates for cell adhesion and proliferation, and both processes were slightly favored on films of the 1:1 PS/PMMA blend. The same results were obtained in terms of cell number and morphology for cells cultured on films, glass coverslips or plastic plates. The chemical characteristics of polymer films make them suitable supports for cell attachment and proliferation, indicating that these films are good candidates for biomedical uses.

ALEA | Rio de Janeiro | vol. 16

O artigo se propõe a pensar a literatura brasileira a partir do paradigma comparativista da “inserção”. Para fixar suas características, faço contraponto ao paradigma hegemônico da formação. Argumento que os dois paradigmas partem de pressupostos muito diferentes no que se refere à presença da cultura brasileira no mundo. A ideia de formação presume uma relação derivativa diante da Europa, vista como modelo a ser emulado. Outra dinâmica de poder surge com a  inserção da literatura brasileira em países africanos, produzindo representações dentre os letrados africanos que igualavam o Brasil ao país deles. O artigo procura tirar consequências das diferenças entre os dois paradigmas.